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Epizyme Inc

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FY2021 Annual Report · Epizyme Inc
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2 0 2 1
R E W R I T I N G
TREATMENT
for cancer through novel 
epigenetic medicines
ANNUAL REPORT

For Epizyme, we made continued progress toward the ambitious 
long-term goals we set forth in our March 2021 vision call; however, 
we could not deny that certain aspects of our business needed to 
change to meet this new reality. As I reflect on the events of the 
past year, inclusive of both my tenure as a board member and my 
transition into the role of Epizyme’s President and CEO in August 
2021, I am incredibly proud of our company’s evolution. We have 
strengthened the foundation of our business and revised our 
playbook – both commercially and clinically – to support our long-
term growth strategy. Amidst many organizational changes in the 
past year, we made progress in realizing our mission of re-writing 
treatment 
for 
cancer 
through 
the 
development 
and 
commercialization of novel epigenetic medicines, and we did so 
while we, along with many of our biotechnology peers, navigated 
significant challenges posed by the financial markets and 
COVID-19. I am incredibly proud of how we have adapted to 
those hurdles, and I believe we are now more focused on what 
matters most.
We have often spoken of our four strategic imperatives, or the four 
“pillars” of our five-year corporate strategy, which we refer to as 
The Next EPIsode: Rewriting Oncology Treatment with Epigenetics. 
In 2021, I believe we made meaningful progress toward each one 
of these pillars:
DEAR FELLOW STAKEHOLDERS,
2021 was another unprecedented year for the biotechnology 
industry. From new variants to vaccines, the COVID-19 
pandemic continued to transfix the world and transform our 
industry. We also navigated significant financial market 
turbulence, particularly within the biotech sector, with the XBI 
(biotech index) down 20% in 2021, in comparison to the S&P 500 
and Nasdaq, which were up 27% and 21%, respectively. 
1. Maximizing our effectiveness as a commercial organization
2021 marked the first full year of TAZVERIK® (tazemetostat) 
commercialization and we generated net product revenues of
$30.9 million for the full year 2021. Total end user demand 
increased from quarter to quarter in 2021, driven primarily by a 
rise in follicular lymphoma (FL) patient sales. We continued to 
make progress on our commercial efforts to educate providers 
and align systems of care to drive prescription growth for 
TAZVERIK as a monotherapy, consistent with our label. As our 
combination studies continue to enroll patients and the data 
mature and read out, we believe TAZVERIK has the potential to 
become a backbone of therapy in FL and other hematological 
malignancies and solid tumors.
2. Building on TAZVERIK’s pipeline-in-a-drug potential
We advanced our tazemetostat development program in both 
hematological malignancies and solid tumors in combination 
with other therapies, both approved and experimental. We 
believe that the core product attributes of tazemetostat, when 
combined with other therapies, have the potential to provide 
new treatment options for patients and the physicians we serve, 
and in so doing, provide greater value for shareholders.
3. Expanding our pipeline and portfolio
Our EZM0414 program, Epizyme’s novel, first-in-class, oral SETD2 
inhibitor, is a prime example of how we have leveraged our 
research and development capabilities to bring new, novel 
oncology therapeutics into the clinic and strengthened our 
position as a leader in epigenetic research. In July 2021, we 
received 
clearance 
from 
the 
U.S. 
Food 
and 
Drug 
Administration (FDA) for our EZM0414 Investigational New Drug 
application. In the fourth quarter of 2021, we initiated our first-in-
human 
SET-101 
study 
of 
EZM0414 
in 
patients 
with 
relapsed/refractory (R/R) multiple myeloma (MM) and diffuse 
large B-cell lymphoma (DLBCL) and received FDA Fast Track 
designation for the treatment of adult patients with R/R DLBCL. 
And in January 2022, 
we 
received 
FDA 
Orphan 
Drug 
designation for the treatment of MM.
4. Collaborating to expand our reach and build value
Collaborations continue to be a strong area of focus for 
Epizyme. 
In 
August 
2021, 
we 
announced 
a 
strategic 
collaboration 
with 
HUTCHMED 
to 
bring 
TAZVERIK 
to 
patients in greater China and to accelerate the global 
development and investigation of TAZVERIK combinations 
with HUTCHMED’s novel oncology medicines portfolio. As part 
of this agreement with HUTCHMED, Epizyme received an 
upfront payment of $25 million, and is eligible to receive up 
to an aggregate of $285 million over the life of the 
collaboration in potential additional future development, 
regulatory and sales milestone payments, in addition to 
royalties on net sales of TAZVERIK in greater China. We plan to 
continue to leverage our existing collaborations and seek to 
identify potential strategic collaborations to further expand 
our reach to patients and grow our business.

•
Preliminary data from our Phase 1b/2 tazemetostat 
hematological basket study (EZH-1501) evaluating 
tazemetostat combinations in patients with hematological 
malignancies; and
•
Key enrollment milestones and preliminary data from the 
Phase 1 portion of SET-101, our first-in-human Phase 1/1b study 
of EZM0414 in patients with R/R MM and DLBCL.
At Epizyme, we aspire to change the standard-of-care for patients 
and physicians by developing targeted, oral medicines with 
fundamentally new mechanisms of action directed at specific 
causes of hematological malignancies and solid tumors. Our plans 
for 2022 are intended to drive prescription growth for TAZVERIK as a 
monotherapy while advancing our key combination clinical 
studies, which we believe have the potential to significantly 
expand the value and reach of TAZVERIK among physicians and 
patients. 
I am deeply grateful for our team’s persistence and commitment to 
executing across our corporate strategy. Given the breadth of our 
clinical development program with two molecules in the clinic, I 
believe Epizyme is entering a new phase in our mission of delivering 
transformative therapies for people with cancer. 
Thank you for your support.
Sincerely,
While advancing against our strategic imperatives, we have also 
been disciplined in making changes to our operating plan, including 
prioritizing our pipeline programs and reducing expenses. As part of 
this process, we made tough decisions, some of which impacted 
members of our team. I want to recognize the contributions of the 
Epizyme employees who were separated from the organization and 
thank them for all of their efforts to advance our company’s mission 
and vision. For those Epizymers who remain with the company, I 
would also like to thank them for their commitment and support as 
we continue to focus and streamline the organization for the benefit 
of all stakeholders, for the future of our company and, most 
importantly, for patients in need of new cancer therapies.
Looking ahead to 2022, we plan to continue to educate providers 
and to align systems of care to support the growth of TAZVERIK 
monotherapy utilization. In addition, with the refined focus on our 
clinical trial programs for both tazemetostat and EZM0414, we 
anticipate several important milestones in the year ahead, including:
•
Enrolling patients in the Phase 3 portion of SYMPHONY-1
(EZH-302), our confirmatory, global Phase 1b/3 study assessing
tazemetostat in combination with rituximab + lenalidomide (R2)
in second-line+ FL patients in addition to sharing updated safety
run-in data from the Phase 1b portion;
•
Interim results from the Lymphoma Study Association (LYSA)
Phase 1b/2 combination study of tazemetostat with R-CHOP in
high-risk, front-line FL and DLBCL patients;
•
Updated safety run-in data as well as interim data from the
Phase 2 efficacy portion of our CELLO-1 (EZH-1101) study
evaluating tazemetostat plus enzalutamide compared to
enzalutamide monotherapy in metastatic castration-resistant
prostate cancer patients;
Grant Bogle
President and Chief Executive Officer
BUILD ON TAZVERIK’S 
PIPELINE-IN-A-DRUG  
POTENTIAL
•  TAZVERIK approved in additional heme and solid
tumor indications
• Robust flow of data read-outs
EXPAND PIPELINE &  
PORTFOLIO TO OVERCOME 
UNDRUGGABLE TARGETS
• Three new clinical-stage programs
• Evolving oncology portfolio company
MAXIMIZE COMMERCIAL 
EFFECTIVENESS
• TAZVERIK adopted as a backbone therapy for FL
• TAZVERIK utilized in multiple combination regimens
COLLABORATE TO EXPAND 
PATIENT REACH & BUILD  
VALUE
• TAZVERIK partnered to reach ex-US markets
• Multiple clinical and scientific collaborations
FOUR PILLARS OF EPIZYME'S CORPORATE STRATEGY

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UNITED STATES 
SECURITIES AND EXCHANGE COMMISSION 
Washington, D.C. 20549 
FORM 10-K 
☒
ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 
For the fiscal year ended December 31, 2021  
or 
☐
TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 
For the transition period from                      to                      
Commission File Number 001-35945 
EPIZYME, INC. 
(Exact name of registrant as specified in its charter) 
 
Delaware
26-1349956
(State or other jurisdiction of
(I.R.S. Employer
incorporation or organization)
Identification No.)
400 Technology Square, 4th Floor
Cambridge, Massachusetts
02139
(Address of principal executive offices)
(Zip code)
617-229-5872 
(Registrant’s telephone number, including area code) 
Securities registered pursuant to Section 12(b) of the Act:
 
Title of each class
Trading symbol(s)
Name of each exchange on which registered
Common stock, $0.0001 par value
EPZM
Nasdaq Global Select Market
Securities registered pursuant to Section 12(g) of the Act: None 
Indicate by check mark if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act.    ☒  Yes    ☐ No 
Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Exchange Act.    ☐ Yes    ☒ No 
Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 
during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing 
requirements for the past 90 days.    ☒ Yes    ☐ No 
Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of 
Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit such files).    
☒ Yes    ☐ No 
Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company, or an 
emerging growth company. See definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company” and “emerging growth company” in 
Rule 12b-2 of the Exchange Act. 
 
Large accelerated filer
☒
Accelerated filer
☐
Non-accelerated filer
☐  
Smaller reporting company
☐
Emerging growth company
☐
If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or 
revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐
Indicate by check mark whether the registrant has filed a report on and attestation to its management’s assessment of the effectiveness of its internal control 
over financial reporting under Section 404(b) of the Sarbanes Oxley-Act (15 U.S.C. 7262(b)) by the registered public accounting firm that prepared or issued 
its audit report   ☒
Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act).    ☐ Yes    ☒ No 
The aggregate market value of the registrant’s common stock, par value $0.0001 per share, held by non-affiliates of the registrant on June 30, 2020, the last 
business day of the registrant’s most recently completed second fiscal quarter, was approximately $794.6 million based on the closing price of the registrant’s 
common stock on the Nasdaq Global Select Market on that date. 
The number of outstanding shares of the registrant’s common stock, par value $0.0001 per share, as of February 24, 2022 was 164,482,036. 
DOCUMENTS INCORPORATED BY REFERENCE 
Portions of the registrant’s definitive proxy statement that the registrant intends to file with the Securities and Exchange Commission pursuant to Regulation 
14A in connection with the registrant’s 2021 Annual Meeting of Stockholders are incorporated by reference into Part III of this Annual Report on Form 10-K 
to the extent stated herein. 

This Page Intentionally Left Blank

Epizyme, Inc.
Annual Report on Form 10-K for the Fiscal Year Ended December 31, 2021
Table of Contents 
Page
Item 
No.
 
PART I 
 
Item 1.
 Business.......................................................................................................................................  
5
Item 1A.  Risk Factors .................................................................................................................................  
45
Item 1B.  Unresolved Staff Comments........................................................................................................  
89
Item 2.
 Properties.....................................................................................................................................  
89
Item 3.
 Legal Proceedings........................................................................................................................  
89
Item 4.
 Mine Safety Disclosures..............................................................................................................  
89
 
PART II
 
Item 5.
 
Market for Registrant’s Common Equity, Related Stockholder Matters and Issuer Purchases 
of Equity Securities .....................................................................................................................  
90
Item 6.
 [Reserved]....................................................................................................................................  
91
Item 7.
 Management’s Discussion and Analysis of Financial Condition and Results of Operations .....  
92
Item 7A.  Quantitative and Qualitative Disclosures about Market Risk .....................................................  
112
Item 8.
 Financial Statements and Supplementary Data ...........................................................................  
112
Item 9.
 Changes in and Disagreements with Accountants on Accounting and Financial Disclosure .....  
114
Item 9A.  Controls and Procedures..............................................................................................................  
114
Item 9B.  Other Information........................................................................................................................  
116
Item 9C. Disclosure Regarding Foreign Jurisdictions That Prevent Inspections.......................................
 
PART III
 
Item 10.  Directors, Executive Officers and Corporate Governance ..........................................................  
117
Item 11.  Executive Compensation .............................................................................................................  
117
Item 12.
 
Security Ownership of Certain Beneficial Owners and Management and Related Stockholder 
Matters.........................................................................................................................................  
117
Item 13.  Certain Relationships and Related Transactions, and Director Independence............................  
117
Item 14.  Principal Accounting Fees and Services .....................................................................................  
117
 
PART IV
 
Item 15.  Exhibits, Financial Statement Schedules.....................................................................................  
118
Item 16.
Form 10-K Summary
123
 Signatures ....................................................................................................................................  
124
Epizyme® and TAZVERIK® are registered trademarks of Epizyme, Inc. in the United States and other countries.  
Epizyme, Inc. has also submitted trademark applications for Epizyme™ and for TAZVERIK™ in other countries. 
All other trademarks, service marks or other tradenames appearing in this Annual Report on Form 10-K are the 
property of their respective owners. 

This Page Intentionally Left Blank

1
Forward-looking Information 
This Annual Report on Form 10-K contains forward-looking statements that involve substantial risks and 
uncertainties. These statements may be identified by such forward-looking terminology as “anticipate,” “believe,” 
“estimate,” “expect,” “intend,” “may,” “plan,” “predict,” “project,” “target,” “potential,” “will,” “would,” “could,” 
“should,” “continue,” and similar statements or variations of such terms. Our forward-looking statements are based 
on a series of expectations, assumptions, estimates and projections about our company, are not guarantees of future 
results or performance and involve substantial risks and uncertainty. We may not actually achieve the plans, 
intentions or expectations disclosed in our forward-looking statements. Actual results or events could differ 
materially from the plans, intentions and expectations disclosed in these forward-looking statements. Our business 
and our forward-looking statements involve substantial known and unknown risks and uncertainties, including the 
risks and uncertainties inherent in our statements regarding: 

our plans to research, develop and commercialize novel epigenetic therapies for patients with cancer; 

the ongoing commercialization of TAZVERIK;

our sales, marketing and distribution capabilities and strategies, including for the commercialization and 
manufacturing of TAZVERIK and any future products;  

the rate and degree of market acceptance and clinical utility of TAZVERIK and any future products; 

our ongoing and planned clinical trials, including the timing of initiation and enrollment in the trials, the 
timing of availability of data from the trials and the anticipated results of the trials; 

the timing of and our ability to apply for, obtain and maintain regulatory approvals for tazemetostat in 
epithelioid sarcoma, follicular lymphoma and other indications, EZM0414 and any future product 
candidates;

our ability to achieve anticipated milestones under our collaborations or to enter into additional 
collaborations; 

the impact of the COVID-19 pandemic on our business, results of operations, and financial condition;

our intellectual property position; 

our ability to successfully implement and execute on our changes to our commercial strategy and 
organization, adjustments to our operating plans, including operating expense reductions, and leadership 
transitions; and 

our estimates regarding expenses, future revenue, capital requirements and needs for additional 
financing. 
All of our forward-looking statements are made as of the date of this Annual Report on Form 10-K only. In each 
case, actual results may differ materially from such forward-looking information as a result of various important 
factors. We can give no assurance that such expectations or forward-looking statements will prove to be correct. An 
occurrence of or any material adverse change in one or more of the risk factors or risks and uncertainties referred to 
in this Annual Report on Form 10-K or included in our other public disclosures or our other periodic reports or other 
documents or filings filed with or furnished to the Securities and Exchange Commission could materially and 
adversely affect our business, prospects, financial condition and results of operations. Except as required by law, we 
do not undertake or plan to update or revise any such forward-looking statements to reflect actual results, changes in 
plans, assumptions, estimates or projections or other circumstances affecting such forward-looking statements 
occurring after the date of this Annual Report on Form 10-K, even if such results, changes or circumstances make it 
clear that any forward-looking information will not be realized. Any public statements or disclosures by us 
following this Annual Report on Form 10-K which modify or impact any of the forward-looking statements 

2
contained in this Annual Report on Form 10-K will be deemed to modify or supersede such statements in this 
Annual Report on Form 10-K.  
Note regarding certain references in this Annual Report on Form 10-K 
Unless otherwise stated or the context indicates otherwise, all references herein to “Epizyme,” “Epizyme, Inc.,” 
“we,” “us,” “our,” “our company,” “the Company” and similar references refer to Epizyme, Inc. and its wholly 
owned subsidiary, Epizyme Securities Corporation. 
In addition, unless otherwise stated or the context indicates otherwise, all references in this Annual Report on Form 
10-K to “TAZVERIK (tazemetostat),” “TAZVERIK” and “TAZVERIK” refer to tazemetostat in the context of the 
commercially-available product for which we received accelerated approval from the United States Food and Drug 
Administration in January 2020 for epithelioid sarcoma and in June 2020 for follicular lymphoma, as more fully 
described herein; whereas, unless otherwise stated or the context indicates otherwise, all references herein to 
“tazemetostat” refer to tazemetostat in the context of the product candidate for which we are exploring further 
applications and indications, as more fully described herein.  
Risk Factors Summary
Our business is subject to a number of risks of which you should be aware in evaluating our company and our 
business. These risks are discussed more fully below in the “Risk Factors” section of this Annual Report on Form 
10-K for the year ended December 31, 2021. These risks include the following:

We are dependent on the successful development and commercialization of tazemetostat. If we do not 
successfully commercialize TAZVERIK for the indications for which TAZVERIK is approved or are unable 
to develop, obtain marketing approval of, and commercialize tazemetostat for additional indications, either 
alone or through collaborations, or if we experience significant delays in doing so, our business could be 
harmed.

In connection with the accelerated approval of our epithelioid sarcoma, or ES, new drug application and our 
follicular lymphoma, or FL, supplemental NDA, continued approval of TAZVERIK for these approved 
indications is contingent upon verification and description of clinical benefit in a confirmatory program in 
each indication. We are conducting Phase 1b/3 trials to confirm the clinical benefit of TAZVERIK in each 
indication. These trials are expensive and time-consuming and may not confirm such benefit. If a confirmatory 
program does not verify clinical benefit for an indication, we may have to withdraw our accelerated approval 
for that indication, which could significantly harm our business.

The marketing approval process is expensive, time-consuming and uncertain and we may be unable to obtain 
approvals for the commercialization of tazemetostat in the United States for any additional indication or in any 
foreign jurisdiction, or of EZM0414 or any other future product candidates we may develop. If we are not able 
to obtain, or if there are delays in obtaining, required marketing approvals of tazemetostat in the United States 
for any additional indication or in any foreign jurisdiction, or of EZM0414 or any other future product 
candidates we may develop, we will not be able to commercialize tazemetostat for such indications or in such 
foreign jurisdiction or such other future product candidates, and our ability to generate revenue will be 
materially impaired.

The COVID-19 pandemic has impacted and may continue to impact our commercial launch efforts for 
TAZVERIK in FL and ES and has led to some delays in clinical trial startup, may affect our ability to initiate 
and complete preclinical studies and our ongoing and planned clinical trials, disrupt regulatory activities, 
further disrupt commercialization of TAZVERIK, or have other adverse effects on our business and 
operations.

Tazemetostat,EZM0414 or any other future product candidate that we commercialize may fail to achieve the 
degree of market acceptance by physicians, patients, third-party payors and others in the medical community 
necessary for commercial success. If tazemetostat, EZM0414 or any other future product candidate does not 

3
achieve an adequate level of acceptance, we may not generate significant product revenues and we may not 
become profitable.

If we are unable to maintain effective sales, marketing and distribution capabilities, we may not be successful 
in commercializing tazemetostat or any other future product candidates that we commercialize.

We face substantial competition, which may result in others discovering, developing or commercializing 
products before or more successfully than we do. Our commercial opportunity could be reduced or eliminated 
if our competitors develop and commercialize products that are safer, more effective, have fewer or less 
severe side effects, are more convenient or are less expensive than tazemetostat for ES, FL or any other 
indication for which we may develop tazemetostat or any other future product candidates that we may 
commercialize.

Tazemetostat and any other future product candidate that we commercialize may become subject to 
unfavorable pricing regulations, third-party reimbursement practices or healthcare reform initiatives, which 
could adversely impact the product revenues we may generate from tazemetostat or such other future product 
candidate and harm our business. 

Our research and development is focused on the creation of novel epigenetic therapies for patients with 
cancer, which is a rapidly evolving area of science, and the approach we are taking to discover and develop 
drugs is novel. 

Clinical drug development is a lengthy and expensive process, with an uncertain outcome. We are conducting 
multiple clinical trials of tazemetostat in different potential indications as a monotherapy and in combination 
with other products. A failure of one or more of these clinical trials can occur at any stage of testing. The 
outcome of preclinical testing and early clinical trials may not be predictive of the success of later clinical 
trials, the outcome of a clinical trial for an indication may not be predictive of the success of clinical trials for 
other indications, and interim results of a clinical trial do not necessarily predict final results. Moreover, 
preclinical and clinical data are often susceptible to varying interpretations and analyses, and many companies 
that have believed their product candidates performed satisfactorily in preclinical studies and clinical trials 
have nonetheless failed to obtain marketing approval of their products.

If we are required by the U.S. Food and Drug Administration, or FDA, to obtain approval of a companion or 
complementary diagnostic in connection with approval of a therapeutic product, and there are delays in 
obtaining such FDA approval of a diagnostic device, we will not be able to commercialize the product 
candidate and our ability to generate revenue will be materially impaired.

We may not be successful in our efforts to use and expand our proprietary drug discovery platform to build or 
advance a pipeline of future product candidates.

Our existing therapeutic collaborations are important to our business and provide us with resources and 
capabilities we may not otherwise have. If we are unable to enter into additional therapeutic collaborations on 
acceptable terms or at all or maintain any of these collaborations, or if these collaborations are not successful, 
our business could be adversely affected.

We contract with third parties for the manufacture of tazemetostat for commercialization and clinical testing, 
and expect to contract with third parties for the manufacture of any other future product candidates that we 
develop for preclinical and clinical testing and commercialization. This reliance on third parties increases the 
risk that we will not have sufficient quantities of tazemetostat or other future product candidates or such 
quantities at an acceptable cost or quality, which could delay, prevent or impair our development or 
commercialization efforts.

Our success depends in large part on our ability to obtain and maintain patent protection in the United States 
and other countries with respect to our proprietary technology and products. If we are unable to obtain and 
maintain patent protection for our technology and products or if the scope of the patent protection obtained is 
not sufficiently broad, our competitors could develop and commercialize technology and products similar or 
identical to ours, and our ability to successfully commercialize our technology and products may be impaired.

We have incurred significant losses since our inception. We expect to incur significant expenses and operating 
losses over the next several years and may never achieve or maintain profitability.

4

We will need substantial additional funding to maintain and grow our operations. If we are unable to raise 
capital when needed or on acceptable terms, we could be forced to delay, reduce or eliminate our research and 
development programs or our commercialization efforts.

Our changes to our commercial strategy and organization, adjustments to our operating plans, including 
operating expense reductions, prioritization of development activities and leadership transitions may not be 
successful, may not result in accelerated commercial adoption of TAZVERIK and greater product revenues or 
anticipated savings, could result in total costs and expenses that are greater than expected, could result in us 
forgoing business opportunities and could disrupt our business.

We have incurred secured indebtedness of $220.0 million under our amended and restated loan agreement 
with BioPharma Credit Investments V (Master) LP, BPCR Limited Partnership and BioPharma Credit PLC. 
Our debt service obligations could limit cash flow available for our operations and expose us to risks that 
could adversely affect our business, financial condition and results of operations. In the event of a default of 
our obligations under the loan agreement, we may not have sufficient funds or the ability to raise capital to 
repay our indebtedness.

5
PART I 
Item 1. Business 
Note on the COVID-19 Pandemic
The ongoing COVID-19 pandemic continues to have widespread, evolving, and unpredictable impacts on global 
economies, financial markets, business practices and societies. We are closely monitoring the impact of the COVID-
19 pandemic and related developments on our business, operations and financial performance. Our focus remains on 
continuing to advance our efforts with respect to the commercialization of TAZVERIK® and to continue to advance 
the development of our pipeline, while making the health and safety of our employees and their families, healthcare 
providers, patients and communities a top priority. We believe that the COVID-19 pandemic has had an adverse 
impact on sales of TAZERIK and the initiation of clinical trials since the June 2020 FDA approval of TAZVERIK 
for follicular lymphoma, or FL. Due to the evolving and uncertain global impacts of the COVID-19 pandemic, 
however, we cannot precisely determine or quantify the impact that this pandemic has had on our business, 
operations and financial performance to date or the impact that this pandemic will have in 2022 and beyond. Please 
see “Risk Factors” in Part I, Item 1A and “Management’s Discussion and Analysis of Financial Condition and 
Results of Operations” in Part II, Item 7 of this Annual Report on Form 10-K for further discussion regarding the 
impact and the risk of the COVID-19 pandemic on our business, operations and financial performance.
Overview 
We are a commercial-stage biopharmaceutical company that is committed to rewriting treatment for people with 
cancer through the discovery, development, and commercialization of novel epigenetic medicines. We aspire to 
change the standard of care for patients and physicians by developing targeted medicines with fundamentally new 
mechanisms of action directed at specific causes of hematological malignancies and solid tumors. 
We have one approved product, TAZVERIK (tazemetostat), which was granted accelerated approval by the U.S. 
Food and Drug Administration, or FDA, in 2020 for epithelioid sarcoma, or ES, and FL. Our focus is on 
maximizing our effectiveness as a commercial organization to achieve adoption of TAZVERIK among as many 
appropriate patients as possible, including in earlier treatment lines and in combination regimens with the data to 
support this expanded use; building on TAZVERIK’s pipeline-in-a-drug potential; and expanding our pipeline and 
evolving oncology portfolio, including with SET-101, our first-in-human Phase 1/1b trial of EZM0414, our novel, 
first-in-class, oral SETD2 inhibitor. We are leveraging our drug discovery platform and expertise as a leader in 
epigenetics, as well as our team’s deep experience across clinical development and commercialization to execute on 
our strategy.
In January 2020, the FDA granted accelerated approval of TAZVERIK (tazemetostat), an oral, first in class, 
selective small molecule inhibitor of the EZH2 histone methyltransferase, or HMT, for the treatment of adult and 
pediatric patients aged 16 years and older with metastatic or locally advanced ES not eligible for complete 
resection. This approval was based on overall response rate and duration of response data shown in the ES cohort of 
our Phase 2 trial in patients with INI1-negative tumors. We continue to make TAZVERIK available to eligible 
patients and their physicians in the United States. 
As part of the accelerated approval for ES, continued approval for this indication is contingent upon verification and 
description of clinical benefit in a confirmatory trial. To provide this confirmatory evidence to support a full 
approval of TAZVERIK for this indication, we are conducting a single, randomized, controlled Phase 1b/3 
confirmatory trial in the United States (EZH-301) assessing tazemetostat in combination with doxorubicin 
compared with doxorubicin plus placebo as a front-line treatment for ES. The trial is expected to enroll 
approximately 152 patients. We have completed the planned enrollment in the Phase 1b safety run-in portion of the 
trial, and the Phase 3 efficacy portion of the trial is open for accrual. We reported safety and preliminary activity 
data from the patients in the safety run-in portion of the EZH-301 trial at the American Society of Clinical 
Oncology (ASCO) Annual Meeting in June 2021. 
In June 2020, the FDA approved a supplemental New Drug Application, or sNDA, for TAZVERIK for adult 
patients with relapsed or refractory (R/R) FL whose tumors are positive for an EZH2 mutation as detected by an 
FDA-approved test and who have received at least two prior systemic therapies, and adult patients with R/R FL who 
have no satisfactory alternative treatment options. These indications were approved under accelerated approval with 

6
a priority review, based on overall response rate and duration of response data shown in the FL cohorts of our Phase 
2 clinical trial in patients with EZH2 mutations and wild-type EZH2. We continue to make TAZVERIK available to 
eligible patients and their physicians in the United States. 
As part of the accelerated approval for FL, continued approval for these R/R FL indications is contingent upon 
verification and description of clinical benefit in a confirmatory trial. To provide this confirmatory evidence to 
support a full approval of TAZVERIK for these indications, we are conducting a single global, randomized, 
adaptive Phase 1b/3 confirmatory trial (EZH-302, SYMPHONY-1) assessing the combination of tazemetostat with 
“R2” (lenalidomide and rituximab), an approved chemotherapy-free treatment regimen, compared with R2 plus 
placebo for R/R FL patients in the second-line or later treatment setting. We plan to leverage the confirmatory trial 
and also conduct post-marketing commitments to expand the TAZVERIK label into the second-line treatment 
setting. 
In December 2021 we presented updated safety and activity data from the Phase 1b safety run-in portion of this 
confirmatory trial at the 2021 American Society of Hematology (ASH) Annual Meeting. We continue to follow the 
40 patients in the Phase 1b safety run-in portion of the trial, and we expect to present follow-up data from the safety 
run-in portion of the trial at a medical conference later in 2022. 
We expect that the Phase 3 portion of the SYMPHONY-1 trial will be a global, randomized and adaptive 
confirmatory trial in 500 patients. Based on the Phase 1b safety run-in results, in December 2021 we submitted a 
protocol amendment to the FDA with 800 mg twice-daily as the recommended tazemetostat dose (RP3D) for the 
Phase 3 portion of the trial. After completing the 30-day voluntary waiting period following submission of the 
protocol amendment for 800 mg RP3D without any objection from the FDA, and as we continue to conduct the 
Phase 1b safety run-in portion of the trial, we have accelerated global start-up activities and are activating as many 
study sites as possible, globally, for the Phase 3 portion of the trial. The primary endpoint for the Phase 3 portion of 
the trial will be based on progression free survival as determined by investigator. Based on discussions with the 
FDA, this portion of the trial will include two interim analyses, the first of which is for futility only and the second 
of which will be conducted for futility, and if 65% of progression free survival events have occurred, the trial will 
also include an efficacy evaluation. In July 2021 China’s Center for Drug Evaluation, or CDE, approved the 
Investigational New Drug Application, or IND, we filed in China for SYMPHONY-1. We are currently screening 
patients in the Phase 3 portion of this trial and we expect to enroll the first patient in the Phase 3 portion of this trial 
in the first quarter of 2022.
Through our planned development efforts, including the following trials, our intention is to eventually make 
TAZVERIK available in all lines of treatment for patients with FL. 

In collaboration with The Lymphoma Study Association, or LYSA, and based on clinical activity 
observed with tazemetostat in combination with R-CHOP (rituximab, cyclophosphamide, doxorubicin, 
vincristine and prednisolone) as a front-line treatment for patients with high risk diffuse large B-cell 
lymphoma, or DLBCL, LYSA is conducting a Phase 1b/2 clinical trial to evaluate this combination as a 
front-line treatment for high-risk patients with FL and DLBCL. Patient enrollment in the Phase 2 
portion of this trial is now nearly complete with 111 patients out of a target of approximately 122 
patients in DLBCL and 61 patients out of a target of approximately 62 patients in FL enrolled as of 
February 23, 2022. We expect that interim results from the Phase 2 portion of this trial will be presented 
at a medical conference in the second half of 2022.

In addition, we are finalizing plans for investigator-sponsored studies to evaluate tazemetostat in 
combination with venetoclax or BTK inhibitors for the treatment of patients with FL in the third-line or 
later treatment settings.
We are also developing tazemetostat for the treatment of a broad range of other cancer types in multiple treatment 
settings. Tazemetostat has shown meaningful clinical activity as an investigational monotherapy in multiple cancer 
indications and has been generally well-tolerated across clinical trials to date. We believe tazemetostat is a “pipeline 
in a product” opportunity and plan to explore its potential utility in additional indications and combinations.
There are four areas where we see the greatest potential for tazemetostat, all of which are based on a strong 
scientific hypothesis and are for patients suffering from diseases that would benefit from a new effective and safe 
treatment option, including:

7

Lymphomas and B-cell malignancies, such as DLBCL, mantle cell lymphoma, or MCL, multiple 
myeloma and others; 

Molecularly defined solid tumors, such as chordoma, melanoma, mesothelioma, and tumors harboring 
an EZH2 or SWI/SNF alteration;

PARPi-resistant tumors, such as castration-resistant prostate cancer, small cell lung cancer, and others; 
and 

Immuno-oncology sensitive tumors, such as small cell lung cancer, prostate cancer, and others. 
As part of these broader tazemetostat development efforts, we are evaluating tazemetostat for the treatment of 
prostate cancer. We are conducting a global, multi-center, open-label, randomized Phase 1b/2 trial (EZH-1101, 
CELLO-1) evaluating tazemetostat in combination with enzalutamide or abiraterone plus prednisone, the standard of 
care treatments for metastatic castration-resistant prostate cancer, or mCRPC. As of February 2021, we had 
completed enrollment in the Phase 1b safety run-in portion of CELLO-1 with a total of 21 men with mCRPC. In 
September 2021, at the European Society for Medical Oncology (ESMO) Congress, we announced preliminary data 
from the Phase 1b safety run-in portion of the trial with a data cutoff date of July 22, 2021. We continue to follow 
patients from the Phase 1b portion of the study, and we expect to present updated data from these patients in the 
second half of 2022. Based on early safety and activity findings observed in the Phase 1b safety run-in portion of 
CELLO-1, in the first quarter of 2021 we initiated enrollment in the Phase 2 efficacy portion of CELLO-1 
evaluating tazemetostat in combination with enzalutamide compared to enzalutamide alone, and we expect to 
include 80 men with mCRPC in this Phase 2 portion of the trial. The primary endpoint for CELLO-1 is radiographic 
progression free survival. The Phase 2 efficacy portion of the trial is approximately 75% enrolled toward the target 
of 80 patients, and we expect to complete enrollment in the Phase 2 portion of the trial in 2022. We plan to provide 
updated data from the safety run-in portion of the trial as well as interim data from the Phase 2 portion of the trial in 
the second half of 2022.
To efficiently evaluate tazemetostat’s potential safety and efficacy across multiple types of hematological 
malignancies, we initiated a signal-finding Phase 1b/2 basket study (EZH-1501) evaluating tazemetostat with 
multiple combinations in hematological malignancies in December 2021 and we are actively screening patients for 
enrollment in this study. In the conduct of EZH-1501, we plan to study multiple combinations with standard of care 
therapies and novel mechanisms of action as we seek to expand the potential of TAZVERIK to patients with 
hematological malignancies and the physicians who treat them. We plan to provide updates as EZH-1501 reaches 
key enrollment milestones and we plan to provide preliminary data from EZH-1501 in the second half of 2022. 
On March 1, 2022, we announced a pipeline reprioritization. Given the breadth of our current tazemetostat clinical 
development program, we have discontinued enrollment in our Phase 2 study of tazemetostat in combination with 
rituximab with FL in the third-line or later treatment settings (SYMPHONY-2, EZH-1401), as well as in our Phase 
1/1b basket study evaluating tazemetostat combinations in patients with solid tumors (EZH-1301). We have enrolled 
five patients in the EZH-1401 study and one patient in the EZH-1301 study and plan to continue to follow the 
patients currently enrolled in each of these two studies. The decision to discontinue these studies was based on 
evolving market dynamics and a continued focus on optimizing our investments and eliminating potentially 
overlapping studies. We continue to study tazemetostat in combination with other therapies for both hematologic 
and solid tumor malignancies, both in ongoing Company-sponsored studies as well as investigator-initiated studies.
We own the global development and commercialization rights to tazemetostat outside of Japan and greater China. 
Eisai Co. Ltd, or Eisai, holds the rights to develop and commercialize tazemetostat in Japan, and Hutchison China 
MediTech Investment Limited, or HutchMed, holds certain rights to develop and commercialize tazemetostat in 
greater China. 
TAZVERIK is available to eligible patients in the United States via a specialty distribution network. Through this 
specialty distribution network, we sell TAZVERIK principally to a limited number of specialty pharmacies, which 
dispense the product directly to patients, and specialty distributors, which in turn sell the product to hospital 
pharmacies and community practice pharmacies for the treatment of patients. To commercialize TAZVERIK for the 
approved ES and FL indications in the United States, we have built a focused field presence and marketing 
capabilities.

8
On August 7, 2021, we entered into a strategic collaboration pursuant to a license agreement with HutchMed 
through which we granted a license to HutchMed for the co-exclusive (with us) development and exclusive 
commercialization of tazemetostat, either as monotherapy or as a part of combinations with other therapies, 
including HutchMed proprietary compounds, agreed by us and HutchMed for the treatment of ES, FL and DLBCL 
in humans, and any additional indications agreed to by us and HutchMed in mainland China, Taiwan, Hong Kong 
and Macau, or the HutchMed Territory.
For other geographies outside the United States, we are evaluating the most efficient path to obtain marketing 
approval, commercialize and distribute TAZVERIK to reach patients, including pursuing potential strategic 
collaborations. Based on comparators and the regulatory landscape, we have decided not to pursue marketing 
approval of tazemetostat as monotherapy from the European Medicines Agency, or EMA at this time. 
Tazemetostat is covered by claims of U.S. and European composition of matter patents, which are expected to 
expire in 2032, exclusive of any patent term or other extensions. Tazemetostat has been granted Fast Track 
designation by the FDA in patients with relapsed or refractory FL, relapsed or refractory DLBCL with EZH2 
activating mutations and metastatic or locally advanced ES who have progressed on or following an anthracycline-
based treatment regimen. The FDA has also granted orphan drug designation to tazemetostat for the treatment of 
patients with malignant rhabdoid tumors, soft tissue sarcoma, and mesothelioma, and a seven-year orphan drug 
exclusivity period from the dates of our respective approvals of TAZVERIK for the treatment of patients with ES 
and for the treatment of patients with FL. 
Beyond tazemetostat, we are utilizing our drug discovery platform to progress preclinical efforts and discover and 
identify additional product candidates to expand our pipeline of inhibitors against several classes of chromatin 
modifying proteins, or CMPs, including HMTs, histone acetyltransferases, or HATs, and helicases. 
Our most advanced product candidate, EZM0414, is a novel first-in-class oral inhibitor of the SETD2 HMT.
SETD2 is an HMT that plays multiple important roles in oncogenesis. Based on the potential of SETD2 inhibition 
demonstrated in multiple preclinical settings, including multiple myeloma, and in particular high risk t(4;14) 
multiple myeloma and in other B-cell malignancies such as DLBCL, as well as in combination with existing and 
emerging therapies including tazemetostat, we submitted an IND for EZM0414 to the FDA in July 2021. We 
received “study may proceed” from the FDA with respect to our IND for EZM0414 in July 2021. In October 2021, 
EZM0414 was granted Fast Track designation by the FDA in adult patients with relapsed or refractory DLBCL and 
in January 2022 we received orphan drug designation from the FDA for EZM0414 for the treatment of multiple 
myeloma. In the fourth quarter of 2021, we initiated a Phase 1/1b trial (SET-101) intended to evaluate the safety and 
optimize the dose and schedule of EZM0414 in R/R multiple myeloma and DLBCL patients. The Phase 1 portion of 
our SET-101 trial is a 3 + 3 dose escalation design and includes six planned dose levels ranging from 100 mg to 900 
mg once daily. Once we have optimized the dose, we then expect to expand the trial to two patient cohorts in 
multiple myeloma: t(4;14) multiple myeloma and non t(4;14) multiple myeloma. Based on dose optimization data 
from the trial, we may add a third patient cohort in DLBCL. We are screening patients with one site open for the 
Phase 1 dose escalation portion of the SET-101 trial, which we expect will enroll between 30-36 patients. We plan 
to provide updates as the trial reaches key enrollment milestones along with preliminary data from the trial in 2022. 
To date we have entered into various strategic collaborations, including with Eisai, HutchMed, Roche and other 
third parties. As one of several key aspects of our strategy, we plan to continue to leverage our existing 
collaborations and to seek to identify new potential strategic collaborations to further support and grow our business 
in and outside of the United States.
Our Corporate Strategy 
We are a commercial-stage biopharmaceutical company that is committed to rewriting treatment for people with 
cancer through the discovery, development and commercialization of novel epigenetic medicines. We aspire to 
change the standard of care for patients and physicians by developing targeted medicines with fundamentally new 
mechanisms of action directed at specific causes of hematological malignancies and solid tumors. 
Our corporate strategy is focused on four critical imperatives that we refer to as The Next EPIsode: Rewriting 
Oncology Treatment with Epigenetics: 

9

Maximize our effectiveness as a commercial organization to achieve adoption of TAZVERIK among as 
many FL and ES patients as possible, including in earlier treatment lines and in combination regimens 
with the data to support this potential expanded use; 

 Build on TAZVERIK’s pipeline-in-a-drug potential, demonstrating tazemetostat’s benefit in additional 
hematological malignancies and solid tumors; 

 Expand our pipeline and evolving oncology portfolio, bringing novel oncology therapeutics into 
clinical development to maintain our position as a leader in epigenetics; and 

Leverage options to expand patient reach, including through commercial, clinical and research 
collaborations. 
TAZVERIK (tazemetostat) for Epithelioid Sarcoma 
In January 2020, the FDA granted accelerated approval of TAZVERIK (tazemetostat) for the treatment of adults and 
pediatric patients aged 16 years and older with metastatic or locally advanced ES not eligible for complete resection. 
This approval was based on overall response rate and duration of response shown in an open-label, single-arm 
cohort of a multi-cohort, global Phase 2 trial of tazemetostat in adults with INI1-negative tumors. The cohort was 
conducted in 62 patients with histologically confirmed, metastatic or locally advanced ES. Patients were required to 
have INI1 loss, detected using local tests, and an Eastern Cooperative Oncology Group performance status, or 
ECOG PS, of 0-2. Patients in the cohort received TAZVERIK 800 mg orally twice daily until disease progression or 
unacceptable toxicity. Tumor response assessments were performed every eight weeks. The major efficacy outcome 
measures were confirmed overall response rate, or ORR, according to Response Evaluation Criteria in Solid 
Tumors, or RECIST, v1.1, as assessed by blinded independent central review, and duration of response. Median 
duration of follow-up was 14 months (range 0.4 to 31).
Among the 62 patients who received TAZVERIK, the median age was 34 years (range 16 to 79); 63% were male, 
76% were White, 11% were Asian, 44% had proximal disease, 92% had an ECOG PS of 0 or 1, and 8% had an 
ECOG PS of 2. Prior surgery occurred in 77% of patients; 61% received prior systemic chemotherapy.
In the total of 62 patients treated, the overall response rate (95% confidence interval) was 15% (7%, 26%), with 
1.6% of patients achieving a complete response and 13% achieving a partial response. Among responders in the 
trial, 67% had a duration of response of six months or longer as of the data cutoff date of September 17, 2018. 
Serious adverse reactions occurred in 37% of patients receiving TAZVERIK. The serious adverse reactions in ≥3% 
of patients who received TAZVERIK were hemorrhage, pleural effusion, skin infection, dyspnea, pain, and 
respiratory distress.
One patient (2%) permanently discontinued TAZVERIK due to an adverse reaction of altered mood.
Dosage interruptions due to an adverse reaction occurred in 34% of patients who received TAZVERIK. The most 
frequent adverse reactions requiring dosage interruptions in ≥3% of patients were hemorrhage, increased alanine 
aminotransferase (ALT), and increased aspartate aminotransferase (AST). Dose reduction due to an adverse reaction 
occurred in one (2%) patient who received TAZVERIK due to decreased appetite.
The most common adverse reactions (≥20%, any grade) were pain, fatigue, nausea, decreased appetite, vomiting, 
and constipation.
The label for TAZVERIK includes warning and precautions for the increase in risk of developing secondary 
malignancies following treatment with TAZVERIK and the risk of embryo fetal toxicity when administered to 
pregnant women.
The Lancet Oncology published results of our Phase 2 trial evaluating TAZVERIK for the treatment of ES in 
October 2020.
We continue to make TAZVERIK available to eligible patients and their physicians in the United States.

10
Background on ES: Epithelioid sarcoma is an ultra-rare and aggressive type of soft tissue sarcoma, comprising less 
than 1 percent of all soft tissue sarcoma cases, and is characterized by a loss of the INI1 protein. It is most 
commonly diagnosed in young adults (20-40 years old) and is often fatal. There is no established standard-of-care 
for treating these patients, who are typically resistant to chemotherapy. Patients diagnosed with metastatic disease 
typically have a 5-year overall survival rate of zero percent and there are no approved treatment options specifically 
indicated for ES other than TAZVERIK. Typically, once patients have been deemed appropriate for systemic 
therapy, most are treated with chemotherapy. There are an estimated 800 patients in the United States living with ES 
with approximately 300 patients with metastatic or locally advanced disease that are eligible for systemic therapy.
TAZVERIK for Epithelioid Sarcoma Post-Marketing Requirements
Confirmatory Trial.  As part of the accelerated approval for ES, continued approval for this indication is contingent 
upon verification and description of clinical benefit in a confirmatory trial. To provide this confirmatory evidence to 
support a full approval of TAZVERIK for this indication, we are conducting a 1:1 randomized, controlled Phase 
1b/3 clinical trial in the United States in the front-line treatment setting comparing tazemetostat in combination with 
doxorubicin, a commonly used systemic treatment in this setting, versus placebo plus doxorubicin. The trial is 
expected to enroll approximately 152 ES patients. The primary efficacy endpoint of the Phase 3 portion of the trial is 
progression-free survival, and secondary efficacy endpoints include overall survival, disease control rate, overall 
response rate, duration of response and health-related quality of life. We have completed the planned enrollment in 
the Phase 1b safety run-in portion of the trial, and the Phase 3 efficacy portion of the trial is open for accrual. We 
reported safety and preliminary activity data from patients in the safety run-in portion of the trial at the ASCO 
annual meeting in June 2021. 
We have several additional post-marketing activities underway, intended to address aspects of the label in the future. 
These include clinical pharmacology evaluations to assess the effect of TAZVERIK on liver function and the effect 
of CYP3A inhibitors and inducers on TAZVERIK for patients with ES. We have also expanded enrollment in a 
cohort of our Phase 2 study in adults with INI1-negative tumors, to enroll a total of at least 60 ES patients. The 
cohort is a paired biopsy cohort designed to assess potential immune biomarkers, and the expansion is intended to 
provide more experience in patients with ES.
TAZVERIK for Follicular Lymphoma
In June 2020, the FDA approved an sNDA for TAZVERIK for the following FL indications: (1) adult patients with 
relapsed or refractory FL whose tumors are positive for an EZH2 mutation as detected by an FDA-approved test and 
who have received at least two prior systemic therapies, and (2) adult patients with relapsed or refractory FL who 
have no satisfactory alternative treatment options. These indications were approved under accelerated approval with 
a priority review, based on overall response rate and duration of response shown in the FL cohorts of our Phase 2 
clinical trial in patients with EZH2 mutations and wild-type EZH2. 
TAZVERIK was evaluated in an open-label, single-arm, multi-center Phase 2 clinical trial in patients with 
histologically confirmed FL whose disease had progressed following at least two prior systemic treatment regimens. 
Patients were enrolled into two cohorts: one cohort enrolled 45 patients with EZH2 activating mutations and a 
second cohort enrolled 54 patients with wild-type EZH2. All patients were treated with 800 mg of tazemetostat, 
administered orally twice a day. The major efficacy outcome measures were overall response rate (ORR) and 
duration of response (DOR) according to the International Working Group Non-Hodgkin Lymphoma (IWG-NHL) 
criteria (Cheson 2007) as assessed by Independent Review Committee. Median duration of follow-up was 22 
months for patients with EZH2 activating mutations and 36 months for patients with wild-type EZH2.
Among the 45 FL patients with an EZH2 activating mutation who received TAZVERIK, the median age was 62 
years (range 38 to 80); 42% were male; 42% had early progression following front-line therapy (POD24); and all 
had an ECOG PS of 0 or 1. The median number of lines of prior systemic therapy was 2.0 (range 1 to 11); 49% were 
refractory to rituximab and 49% were refractory to their last therapy. In the 42 patients treated with at least two prior 
systemic therapies, the ORR (95% confidence interval) was 69% (53%, 82%), with 12% of patients achieving a 
complete response and 57% achieving a partial response. The median DOR was 10.9 months and ongoing.

11
Among the 54 FL patients with wild-type EZH2 who received TAZVERIK, the median age was 61 years (range 36 
to 87); 63% were male; 59% had POD24; and 91% had an ECOG PS of 0 or 1. The median number of lines of prior 
systemic therapy was 3.0 (range 1 to 8); 59% were refractory to rituximab and 41% were refractory to their last 
therapy. In the 53 patients treated with at least two prior systemic therapies, the ORR (95% confidence interval) was 
34% (22%, 48%), with 4% of patients achieving a complete response and 30% achieving a partial response. The 
median DOR was 13.0 months.
Serious adverse reactions, irrespective of attribution, occurred in 30% of patients receiving TAZVERIK. Serious 
adverse reactions in ≥2% of patients who received TAZVERIK were general physical health deterioration, 
abdominal pain, pneumonia, sepsis, and anemia. The most common (≥20%) adverse reactions were fatigue, upper 
respiratory tract infection, musculoskeletal pain, nausea and abdominal pain.
Eight patients (8%) discontinued due to adverse reaction during the trial. There were no reported deaths on study, 
and no black box warnings or contraindications.
The Lancet Oncology published in October 2020 results of our Phase 2 trial evaluating TAZVERIK for the treatment 
of FL.
We continue to make TAZVERIK available to eligible patients and their physicians in the United States.
Background on FL: Follicular lymphoma is the most common indolent lymphoma and the second most common 
non-Hodgkin lymphoma – accounting for about 10-20% of all lymphomas in Western countries. FL is considered to 
be incurable with existing treatments and is characterized by cycles of relapse that become increasingly difficult to 
treat with each disease progression. We estimate that approximately 14,000 patients are diagnosed with FL in the 
United States annually, of whom the majority have advanced disease at diagnosis. We estimate that there are 
approximately 10,000 patients with relapsed and/or refractory disease in the United States. Based on literature and 
an extensive natural history study that we conducted, we believe that approximately 20% of FL tumors carry an 
EZH2 activating mutation. Common treatments for FL include multi-agent chemotherapy, usually combined with 
rituximab (Rituxan), including R-CHOP and R-Bendamustine. Upon clinical progression, treatment regimens are 
typically other combinations of rituximab, and other chemotherapy regimens, utilization of off-label agents, clinical 
trials, or one of the two approved PI3k inhibitors: copanlisib or umbralisib, or one approved CAR-T therapy: 
YESCARTA.
TAZVERIK for Follicular Lymphoma Post-Marketing Requirements
As part of the accelerated approval for FL, continued approval for these indications is contingent upon verification 
and description of clinical benefit in a confirmatory trial. To provide this confirmatory evidence to support a full 
approval of TAZVERIK for these indications, we are conducting a single global, randomized, adaptive Phase 1b/3 
confirmatory trial (EZH-302, SYMPHONY-1) assessing the combination of tazemetostat with “R2” (lenalidomide 
plus rituximab), an approved chemotherapy-free treatment regimen, compared with R2 plus placebo for FL patients 
in the second-line or later treatment setting. 
In December 2021 we presented updated safety and activity data from the Phase 1b safety run-in portion of this 
confirmatory trial at the 2021 ASH Annual Meeting, which included 40 FL patients who had received treatment 
with tazemetostat and R2, including patients at the 400 mg tazemetostat twice daily dosing regimen [n=4], the 600 
mg tazemetostat twice daily dosing regimen [n=18] and the 800 mg tazemetostat twice daily dosing regimen [n=18], 
as of a September 29, 2021 data cutoff date. Through the September 29, 2021 data cutoff date, the safety profile 
observed in the patients in the 400 mg, 600 mg and 800 mg dose cohorts was consistent with safety information in 
the prescribing information for the individual tazemetostat and R2 package inserts, respectively. Additionally, there 
was no clear dose response for treatment-emergent adverse events, or TEAEs, or dose modifications. Thirty-five 
(35) of the 40 patients were evaluable for tumor assessments as of the data cutoff date. Thirty-two (32) patients 
responded to treatment, with 13 patients, or 37.1 percent, having a complete response, and 19 patients, or 54.3 
percent, having a partial response, for an overall response rate of 91.4 percent. The duration of response data 
continue to mature as the Phase 1b safety run-in portion of the trial is ongoing. We continue to follow the 40 patients 
in the Phase 1b safety run-in portion of the trial and we expect to present follow-up data from the safety run-in 
portion of the trial at a medical conference later in 2022. 

12
We expect that the Phase 3 portion of the SYMPHONY-1 trial will be a global, randomized and adaptive 
confirmatory trial in approximately 500 FL patients, stratified based on their EZH2 mutation status. Based on the 
Phase 1b safety run-in results, in December 2021 we submitted a protocol amendment to the FDA with 800 mg 
twice-daily as the recommended tazemetostat dose for the Phase 3 portion of the trial. After completing the 30-day 
voluntary waiting period following submission of the protocol amendment for the 800 mg RP3D without any 
objection from the FDA, and as we continue to conduct the Phase 1b safety run-in portion of the trial, we have 
accelerated global start-up activities and are activating as many study sites as possible, globally, for the Phase 3 
portion of the trial. The primary endpoint for the Phase 3 portion of the trial will be based on progression free 
survival as determined by investigator. Based on discussions with the FDA, this portion of the trial will include two 
interim analyses, the first of which is for futility only and the second of which will be conducted for futility, and if 
65% of progression free survival events have occurred, the trial will also include an efficacy evaluation. In July 
2021 China’s Center for Drug Evaluation, or CDE, approved the IND we filed in China for SYMPHONY-1. We are 
currently screening patients in the Phase 3 portion of this trial and we expect to enroll the first patient in the Phase 3 
portion of this trial in the first quarter of 2022.
In addition, we continue to engage with the FDA regarding the conduct of additional post-marketing commitments, 
including with respect to the design of clinical trials in FL patients with wild-type EZH2 to evaluate tazemetostat as 
a monotherapy in patients who have been treated with at least one prior systemic treatment, in order to inform the 
label and potentially expand in the relapsed and refractory setting in the future. 
FL Development Expansion: Through our planned development efforts, our intention is to make TAZVERIK 
available in all lines of treatment for patients with FL. We plan to leverage the confirmatory trial and post-marketing 
commitments to expand TAZVERIK into the second-line treatment setting. 
In collaboration with LYSA and based on clinical activity observed with tazemetostat in a combination Phase 1b/2 
study with R-CHOP as a front-line treatment for patients with high risk DLBCL, in the fourth quarter of 2016 LYSA 
commenced a multi-center Phase 1b/2 trial of tazemetostat in combination with R-CHOP in front-line, elderly high-
risk patients with DLBCL. Primary endpoints in the trial include complete response rate, safety and tolerability of 
the combination. Secondary endpoints include ORR and progression-free survival, or PFS. At ASH 2018, LYSA 
reported interim data from 17 patients in the trial as of March 2018 showing that the combination of the two agents 
had been generally well-tolerated and confirming the recommended tazemetostat dose for the combination to be 800 
mg twice-daily. Clinical activity was observed, with 87 percent of patients experiencing a metabolic complete 
response. We agreed in 2020 to expand the trial to also include an expansion cohort for the front-line treatment of 
high-risk patients with FL. The Phase 1b part of the study has completed. Patient enrollment in the Phase 2 portion 
of this trial is now nearly complete with 111 patients out of a target of approximately 122 patients in DLBCL and 61 
patients out of a target of approximately 62 patients in FL enrolled as of February 23, 2022. We expect that interim 
results from the Phase 2 portion of this trial will be presented at a medical conference in the second half of 2022.
In addition, we are finalizing plans for investigator-sponsored studies to evaluate tazemetostat in combination with 
venetoclax or BTK inhibitors for the treatment of patients with FL in the third-line or later treatment settings. 
Tazemetostat Life-Cycle Development 
Tazemetostat has shown meaningful clinical activity as an investigational monotherapy in multiple cancer 
indications and has been generally well-tolerated across clinical trials to date. We believe tazemetostat is a “pipeline 
in a product” opportunity and plan to explore its utility in additional indications and combinations through both 
Company- and investigator-sponsored studies. There are four areas where we see the greatest potential for 
tazemetostat, all of which are based on a strong scientific hypothesis and are for patients suffering from diseases that 
would benefit from a new effective and safe treatment option.
Lymphomas and B-Cell Malignancies
We are developing tazemetostat for lymphomas and B-cell malignancies, including DLBCL, MCL, multiple 
myeloma and others, because of the role EZH2 plays in B-cell biology. When oncogenic mutations occur, they can 
“lock” B-cells in the germinal center state, leading to a variety of hematologic cancers. Regardless of the oncogenic 
mutation, these cancer cells are governed by EZH2 expression, which enables their growth and proliferation. By 
inhibiting EZH2, we believe we can inhibit tumor proliferation, leading to anti-tumor activity, as seen in FL patients 
with wild-type EZH2.

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Molecularly Defined Solid Tumors 
We are exploring the use of tazemetostat to treat multiple molecularly defined solid tumors, such as chordoma, 
melanoma, mesothelioma and tumors with a SWI/SNF alteration or other mutations. In these tumors, a loss of 
certain proteins or the presence of a certain mutation have been shown to result in abnormal EZH2 activity or 
exaggerated dependence on EZH2, which typically leads to cancer cell growth. By inhibiting EZH2 with 
tazemetostat, we believe we can inhibit that abnormal function, thereby indirectly restoring cells to their natural 
state, which we believe has the potential to result in a therapeutic benefit.
PARPi-Resistant Tumors
We are assessing the use of tazemetostat for PARPi-resistant solid tumors that are resistant to chemotherapy or other 
treatments, such as castration-resistant prostate cancer, small cell lung cancer, and others. EZH2 plays a role in the 
resistance to poly adenosine diphosphate ribose polymerase, or PARP, inhibitors. When PARP inhibitors are given, 
DNA is damaged, which leads to increased EZH2 activity and limits the responsiveness to the PARP inhibitor. By 
blocking EZH2 with tazemetostat, we believe we can also re-sensitize tumors to PARP inhibition treatment.
Castration-Resistant Prostate Cancer: Prostate cancer is the most frequently diagnosed and second most frequent 
cause of cancer deaths among men in the United States. We believe that treatment with an EZH2 inhibitor after 
resistance to the standards-of-care may result in recovery of sensitivity to these agents because, based on published 
literature, EZH2 protein expression has been correlated with progression of metastatic castration-resistant prostate 
cancer, or mCRPC, and moderate to high EZH2 expression has been associated with worse survival. We are 
conducting a global, multi-center, randomized Phase 1b/2 trial (EZH-1101, CELLO-1) evaluating tazemetostat in 
combination with enzalutamide or abiraterone plus prednisone, the standard of care treatments for mCRPC. As of 
February 2021, we had completed enrollment in the Phase 1b safety run-in portion of CELLO-1 with a total of 21 
men with mCRPC. Based on early safety and activity findings observed in the Phase 1b safety run-in portion of 
CELLO-1, in the first quarter of 2021 we initiated enrollment in the Phase 2 efficacy portion of CELLO-1 
evaluating tazemetostat in combination with enzalutamide compared to enzalutamide alone, and we expect to 
include 80 men with mCRPC in this Phase 2 portion of the trial. The primary endpoint for CELLO-1 is radiographic 
progression free survival. The Phase 2 efficacy portion of the trial is approximately 75% enrolled toward the target 
of 80 patients, and we expect to complete enrollment in the Phase 2 portion of the trial in 2022. We plan to provide 
updated data from the safety run-in portion of the trial as well as interim data from the Phase 2 portion of the trial in 
the second half of 2022.
In September 2021, at the European Society for Medical Oncology (ESMO) Congress, we announced preliminary 
data from the Phase 1b safety run-in portion of the trial using a data cutoff date of July 22, 2021. The safety run-in 
portion of CELLO-1 is being conducted using a standard dose escalation design. Among the 21 patients enrolled in 
the safety run-in portion, as of the data cutoff date no dose limiting toxicities, or DLTs, were observed at any dose of 
tazemetostat up to a maximum dose of 1600 mg twice daily for patients receiving tazemetostat plus enzalutamide 
and 800 mg twice daily for patients receiving tazemetostat plus abiraterone. As of the July 22, 2021 cutoff date, 
preliminary data from the trial also showed: 

Median PFS had not been reached at cutoff for the tazemetostat plus enzalutamide arm; six-month PFS 
was 61.7%. 

11 of 21 patients experienced prostate-specific antigen, or PSA, decline from baseline; seven out of 21 
patients had a PSA response of ≥50%; one additional patient had a PSA response of ≥30%.

Six of the PSA50 responses were in the tazemetostat + enzalutamide cohort (n=13) and one was in the 
tazemetostat + abiraterone/prednisone cohort (n=8).

One patient with a PSA50 response achieved a radiographic partial response. 

All PSA50 and PSA30 responses were in ARV7 negative and neuroendocrine subtype negative patients 
identified using the EPIC platform. Only one ARV7 positive patient was enrolled in the safety run-in 
portion of the trial.
PARP-Resistant Solid Tumors: We are continuing with an ongoing investigator-sponsored trial that is intended to 
investigate the therapeutic potential of tazemetostat as a combination therapy with a PARP inhibitor for the 

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treatment of PARP-resistant tumors. In PARP-resistant cancers, PARP inhibitors have shown modest monotherapy 
activity, and we continue to believe tazemetostat may have the potential to enhance the clinical response to PARP 
inhibitors.
Immuno-oncology-sensitive Tumors
We are assessing the use of tazemetostat for immuno-oncology-sensitive tumors, such as small cell lung cancer, 
prostate cancer and others. We believe tazemetostat has the potential to enhance the antitumor immune response by 
interfering with multiple EZH2 functions in the cell. EZH2 inhibition results in tumor-intrinsic and tumor-extrinsic 
effects that reshape the tumor microenvironment to favor antitumor immunity, including increasing antigen 
presentation, increasing effector T cell trafficking, modulating the adaptive anti-tumor response, impairing 
regulatory T cells, inducing the expression of tumor antigens and endogenous retroviruses, and increasing NK cell 
maturation and killing. By inhibiting EZH2, we believe tazemetostat may be able to influence biologic activity in the 
tumor microenvironment, which could enable tumors to be more sensitive or re-sensitized to immune-oncology 
therapies. 
EZM0414, Our SETD2 Inhibitor Program and SET-101, Our Phase 1/1b Trial of EZM0414 
We are developing a novel first-in-class oral inhibitor of SETD2 (EZM0414). SETD2 is an HMT that plays multiple 
important roles in oncogenesis. We submitted an IND for EZM0414 to the FDA in July 2021 based on the potential 
of SETD2 inhibition demonstrated in multiple preclinical settings, including multiple myeloma, and in particular 
high risk t(4;14) multiple myeloma and in other B-cell malignancies such as DLBCL, as well as in combination with 
existing and emerging therapies including tazemetostat. 
We received “study may proceed” from the FDA with respect to our IND for EZM0414 in July 2021. In October 
2021, EZM0414 was granted Fast Track designation by the FDA in adult patients with relapsed or refractory 
DLBCL and in January 2022 we received orphan drug designation from the FDA for EZM0414 for the treatment of 
multiple myeloma. This trial (SET-101), which we initiated in the fourth quarter of 2021, is a Phase 1/1b trial 
intended to evaluate the safety and optimize the dose and schedule of EZM0414 in relapsed or refractory multiple 
myeloma and DLBCL patients. The Phase 1 portion of our SET-101 trial is a 3 + 3 dose escalation design and 
includes six planned dose levels ranging from 100 mg to 900 mg once daily. Once we have optimized the dose, we 
then expect to expand the trial to two patient cohorts in multiple myeloma: t(4;14) multiple myeloma and non 
t(4;14) multiple myeloma. Based on dose optimization data from the trial, we may add a third patient cohort in 
DLBCL. We are screening patients with one site open for the Phase 1 dose escalation portion of the SET-101 trial, 
which we expect will enroll between 30-36 patients. We plan to provide updates as the trial reaches key enrollment 
milestones, along with preliminary data from the trial in 2022.
Our Research Focus 
Beyond tazemetostat and EZM0414, we are utilizing our proprietary drug discovery platform to progress preclinical 
efforts and discover and identify additional product candidates to expand our pipeline of inhibitors against several 
classes of CMPs, including HMTs, HATs, and helicases. These programs are directed against both hematological 
malignancies and solid tumors and include biomarker approaches to patient stratification.
Our Epigenetic Approach 
Epigenetics refers to a broad regulatory system that controls gene expression without altering the sequence of the 
genes themselves. Genes are composed of DNA, and in nature, this DNA is wrapped around a core of proteins 
known as histones. Together, the DNA and histone proteins form a complex known as chromatin that is the basic 
structural component of chromosomes. 
Gene regulation is determined by chromatin structure. The dynamics of chromatin structure are regulated through 
multiple mechanisms by CMPs. Some CMPs place chemical groups onto specific sites on histones or DNA, some 
remove these marks in site-specific ways, others recognize the uniquely marked sites on histones and bind to these 
marked sites, and still other CMPs drive topological changes to histone-DNA interactions within chromatin. Where, 
when and how such chromatin structure changes occur determines which genes in a cell are turned “on” or “off” at 

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any particular time. When the function of these CMPs is altered, the program of gene expression is changed in ways 
that can lead to disease. 
To further support our leadership position in epigenetics, we are discovering and developing inhibitors of CMPs as 
novel therapeutics for patients with cancer. Our focus is on the discovery, development and commercialization of 
small molecule inhibitors of CMPs for applications in diseases that are uniquely dependent on the enzyme activity of 
a specific CMP. Among the CMP target classes, we have had a particular emphasis on the HMTs, which have been 
shown to play pathogenic roles in a number of human diseases. Today, we have programs in HMTs as well as 
additional target classes, including HATs, and helicases. We believe that targeting pathogenic CMPs affords us 
multiple opportunities to create, develop and commercialize novel therapeutics.
Our Collaborations 
We have entered into several key strategic collaborations, including therapeutic collaborations and other 
collaborations. Since our inception, the therapeutic collaborations have provided us with $268.8 million in non-
equity funding through December 31, 2021. Key terms of our ongoing collaborations are summarized below. 
Eisai 
Overview. In March 2015, we entered into an amended and restated collaboration and license agreement with Eisai, 
under which we reacquired worldwide rights, excluding Japan, to our EZH2 program, including tazemetostat. Under 
the amended and restated collaboration and license agreement, we will be responsible for global development, 
manufacturing and commercialization outside of Japan of tazemetostat and any other EZH2 product candidates, with 
Eisai retaining development and commercialization rights in Japan, as well as a right to elect to manufacture 
tazemetostat and any other EZH2 product candidates in Japan, including the right of first negotiation for the rest of 
Asia. Eisai waived its right of first negotiation for the rest of Asia in 2018. Under the original collaboration and 
license agreement, we had granted Eisai an exclusive worldwide license to our small molecule HMT inhibitors 
directed to EZH2, including tazemetostat, while retaining an opt-in right to co-develop, co-commercialize and share 
profits with Eisai as to licensed products in the United States. 
Upon the execution of the amended and restated collaboration agreement in March 2015, we agreed to pay Eisai a 
$40.0 million upfront payment. We also agreed to pay Eisai up to $20.0 million in clinical development milestone 
payments, including a $10.0 million milestone payment upon the earlier of initiation of a first phase 3 clinical trial of 
any EZH2 product or the first submission of an NDA or Market Authorization Application, or MAA, and a $10.0 
million milestone upon the earlier of initiation of a first phase 3 clinical trial of any EZH2 product or the first 
submission of an NDA or MAA for a second indication, and up to $50.0 million in regulatory milestone payments, 
including a $25.0 million milestone payment upon regulatory approval of the first NDA or MAA, and a $25.0 
million milestone payment upon regulatory approval of the NDA or MAA for the second indication. We are 
obligated to pay royalties at a percentage in the mid-teens on worldwide net sales of any EZH2 product, excluding 
net sales in Japan. In 2019, Eisai sold its rights to these royalties to RPI Finance Trust, which has agreed to certain 
reductions in these royalties in the event certain net sales thresholds are achieved. We are eligible to receive from 
Eisai royalties at a percentage in the mid-teens on net sales of any EZH2 product in Japan. In November 2019, we 
sold our rights to these royalties to RPI Finance Trust. In 2019, we triggered the payment of the two $10.0 million 
milestone payments upon the submission of the NDAs for accelerated approval of tazemetostat for epithelioid 
sarcoma and follicular lymphoma. In January 2020, we triggered the payment of the $25.0 million milestone 
payment upon regulatory approval in the United States of tazemetostat for epithelioid sarcoma and in June 2020 we 
triggered the payment of an additional $25.0 million milestone payment upon regulatory approval in the United 
States of tazemetostat for follicular lymphoma.
Under the original agreement, Eisai was solely responsible for funding all research, development and 
commercialization costs for licensed compounds. Under the amended and restated agreement, we are solely 
responsible for funding global development, manufacturing and commercialization costs for EZH2 compounds 
outside of Japan, and Eisai is solely responsible for funding Japan-specific development and commercialization 
costs for EZH2 compounds. In connection with the amended and restated agreement, we and Eisai agreed to the 
transition to us of ongoing development and manufacturing activities that were being conducted by or on behalf of 
Eisai. In January 2017, as part of Eisai’s obligations under the amended and restated collaboration agreement, Eisai 

16
enrolled and dosed the first patient in a Phase 1 study of tazemetostat in patients with relapsed or refractory B-cell 
NHL in Japan.
In the event that we are awarded a priority review voucher from the FDA with respect to an EZH2 product, Eisai is 
entitled to specified compensation if we use the voucher on a non-EZH2 program or sell the voucher to a third party. 
Governance. Under the amended and restated collaboration and license agreement, development will be guided by a 
joint steering committee, with our company retaining final decision-making authority with respect to global 
development other than with respect to Japan-specific development and commercialization. 
Exclusivity Restrictions. Subject to exceptions specified in the agreement, for an exclusivity period extending until 
eight years after the first commercial sale of a product covered by the agreement, neither we nor Eisai may research, 
develop or commercialize HMT inhibitors directed to EZH2, other than pursuant to the agreement. 
Term and Termination. Our agreement with Eisai will remain in effect until the expiration of all payment obligations 
under the agreement with respect to all licensed products. The royalty term for each licensed product in each country 
commences on the first commercial sale of the applicable licensed product in the applicable country and ends on the 
latest of expiration of specified patent coverage, expiration of specified regulatory exclusivity or ten years following 
the first commercial sale. We or Eisai may terminate the agreement for convenience as to our respective territories, 
upon 90 days’ prior written notice. The agreement will also terminate as to our territory if we cease all development 
and commercialization activities for the United States and specified major countries in Europe and as to Eisai’s 
territory if Eisai ceases all development and commercialization activities for Japan. The agreement may also be 
terminated by either party in the event of an uncured material breach by the other party or by us in the event Eisai, or 
an affiliate or sublicensee, participates or actively assists in an action or proceeding challenging or denying the 
validity of one of our patents. If we terminate the agreement for our convenience, the agreement terminates as a 
result of our cessation of development and commercialization activities or Eisai terminates the agreement for our 
uncured material breach, Eisai may elect to have worldwide development and commercialization rights revert to 
Eisai, and if Eisai so elects, Eisai will be required to pay us specified royalties on net sales of the licensed products 
and reimburse certain development expenses incurred by us. If Eisai terminates the agreement for its convenience, 
the agreement terminates as a result of Eisai’s cessation of development and commercialization activities or we 
terminate the agreement for Eisai’s uncured material breach or Eisai’s, or its affiliate’s or sublicensee’s, 
participation in, or assistance with, an action or proceeding challenging or denying the validity of one of our patents, 
Japanese development and commercialization rights to the licensed products revert to us, and we will be required to 
pay Eisai specified royalties on net sales of licensed products in Japan. 
HutchMed
Overview.  In August 2021, we entered into a strategic collaboration pursuant to a license agreement, or the 
HutchMed License Agreement, with HutchMed for the development, manufacture and commercialization of 
tazemetostat, either as a monotherapy or as a part of combinations with other therapies, including HutchMed 
proprietary compounds, agreed by the parties under the HutchMed License Agreement for the treatment of ES, FL, 
DLBCL in humans, and any additional indications agreed by the parties in accordance with the terms of the 
HutchMed License Agreement in mainland China, Taiwan, Hong Kong and Macau, each a Jurisdiction and 
collectively, the HutchMed Territory.
We have granted HutchMed licenses under patent rights and know-how that we control to enable HutchMed to 
develop and commercialize licensed products for the treatment of ES, FL, DLBCL and any additional indications 
agreed by the parties in the HutchMed Territory. The licenses granted to HutchMed are co-exclusive with us with 
respect to the development of licensed products for the treatment of ES, FL, DLBCL and any additional indications 
agreed by the parties in the HutchMed Territory and exclusive with respect to the commercialization of licensed 
products for the treatment of ES, FL, DLBCL and any additional indications agreed by the parties in the HutchMed 
Territory. We also granted HutchMed a license under patent rights and know-how controlled that we control to 
enable HutchMed to manufacture tazemetostat drug substance and drug product for the purpose of developing and 
commercializing licensed products for the treatment of ES, FL, DLBCL and any additional indications agreed by the 
parties in the HutchMed Territory. We retain development and commercialization rights with respect to licensed 
products in the rest of the world outside of the HutchMed Territory except for Japan. During the term of the 

17
HutchMed License Agreement, each party and its affiliates is prohibited from developing or commercializing any 
other compound or product that inhibits, modulates or degrades EZH1, EZH2, or any other member of the polycomb 
repressive complex 2, including the EED protein for the treatment of ES, FL, DLBCL and any additional indications 
agreed by the parties in the HutchMed Territory, provided that, subject to limitations specified in the HutchMed 
License Agreement, HutchMed may develop its existing preclinical compound that inhibits EZH1 and EZH2 
without the use of know-how or patent rights that we licensed to HutchMed. 
We have agreed to conduct a technology transfer of manufacturing technology to HutchMed to enable HutchMed to 
manufacture clinical and commercial quantities of tazemetostat drug substance and drug product to carry out its 
obligations and exercise its rights under the HutchMed License Agreement. Subject to the execution of a clinical 
supply agreement or commercial supply agreement, as applicable, and until the completion of the technology 
transfer to HutchMed, we have agreed to manufacture and supply HutchMed with tazemetostat drug substance and 
drug product in sufficient quantities for HutchMed’s development or commercialization activities for licensed 
products for the treatment of ES, FL, DLBCL and any additional indications agreed by the parties in the HutchMed 
Territory. 
HutchMed has agreed to use commercially reasonable efforts to carry out development activities in the HutchMed 
Territory as agreed by the parties and to seek to obtain and maintain regulatory approval of the licensed products in 
the HutchMed Territory. HutchMed agreed to use commercially reasonable efforts to commercialize licensed 
products for the treatment of ES, FL, DLBCL and any additional indications agreed by the parties in the HutchMed 
Territory. HutchMed is responsible for all costs it incurs in developing, obtaining regulatory approval of, and 
commercializing licensed products in the HutchMed Territory, including costs incurred by HutchMed in conducting 
clinical trials that only include clinical sites in the HutchMed Territory. For global studies that we conduct and in 
which HutchMed elects to participate by conducting any such study in the HutchMed Territory, HutchMed will be 
responsible for enrolling and treating in the HutchMed Territory 20% of the total number of study patients of such 
global study and will be responsible for costs for those patients enrolled and treated in such trials. HutchMed will 
also be responsible for 20% of the costs of such global studies that are not specific to any territory and we will be 
responsible for all other costs of such global studies. HutchMed has agreed to participate in our EZH-301 and EZH-
302 global studies, however under certain circumstances where the EZH-302 global study is not considered a 
confirmatory trial for regulatory approval in China, we shall be responsible for the costs of the trial in the HutchMed 
Territory.
Pursuant to the HutchMed License Agreement, we received a nonrefundable upfront payment of $25.0 million in 
September 2021. We are also entitled to milestone payments of up to $110.0 million in the aggregate for 
achievement of specified development and regulatory milestones with respect to licensed products in the HutchMed 
Territory, and up to $175.0 million in the aggregate for achievement of specified sales milestones in the HutchMed 
Territory with respect to the licensed products. We will also be entitled to receive tiered royalties, ranging from a 
mid-teens percentage to a low twenties percentage based on HutchMed’s cumulative annual net sales, if any, of 
licensed products in the HutchMed Territory. Royalties are payable for each licensed product commencing on the 
first commercial sale of the applicable licensed product and ending, on a Jurisdiction-by-Jurisdiction basis, on the 
latest of expiration of specified patent coverage, expiration of specified regulatory exclusivity or a specified period 
following the first commercial sale in such Jurisdiction and may be reduced in various circumstances.
Under the HutchMed License Agreement, we issued a warrant to HutchMed, or the “HutchMed Warrant, 
exercisable at any time prior to August 7, 2025 for up to 5,653,000 shares of our common stock at an exercise price 
of $11.50 per share. On September 21, 2021 we filed with the SEC a registration statement on Form S-3 registering 
for resale the shares of our common stock issuable upon exercise of the HutchMed Warrant in accordance with the 
HutchMed Warrant. Such registration statement on Form S-3 was declared effective by the SEC on September 29, 
2021.
Term and Termination.  Unless earlier terminated, the HutchMed License Agreement will expire upon the expiration 
of the last royalty term for the last licensed product for the treatment of ES, FL, DLBCL and any additional 
indications agreed by the parties in the HutchMed Territory. HutchMed may terminate the HutchMed License 
Agreement in its entirety for any or no reason upon 12 months’ prior written notice to us. Either party may, subject 
to specified cure periods, terminate the HutchMed License Agreement in the event of the other party’s uncured 
material breach, and under specified circumstances relating to the other party’s insolvency or if the other party or its 

18
affiliates challenges the validity, patentability, or enforceability of patent rights that are owned by or licensed to such 
party or its affiliates and that are subject to the licenses granted in the HutchMed License Agreement.
LYSA 
In May 2016, we entered into a collaboration agreement with the Lymphoma Academic Research Organization, or 
LYSARC, to conduct a combination trial of tazemetostat. LYSARC is the operational arm of LYSA, a premier 
cooperative group in France dedicated to clinical and translational research for lymphoma. Based on clinical activity 
observed with tazemetostat in a combination Phase 1b/2 trial with R-CHOP as a front-line treatment for patients 
with high risk diffuse large B-cell lymphoma, or DLBCL, we agreed in 2020 to expand the trial to also include an 
expansion cohort for the front-line treatment of high-risk patients with FL. LYSA is conducting the Phase 2 clinical 
expansion trial and the Phase 1b part of the trial has completed. LYSA is managing the study operations for the trial, 
and we are recognizing our share of the related expenses as those costs are incurred over the duration of the trial. 
Primary endpoints in the trial include complete response rate, safety and tolerability of the combination. Secondary 
endpoints include ORR and PFS. Patient enrollment in the Phase 2 portion of this trial is now nearly complete with 
111 patients out of a target of approximately 122 patients in DLBCL and 61 patients out of a target of approximately 
62 patients in FL enrolled as of February 23, 2022. We expect that interim results from the Phase 2 portion of this 
trial will be presented at a medical conference in the second half of 2022.
GSK 
On December 16, 2021, we received written notice from Glaxo Group Limited, or GSK, that GSK had elected to 
terminate the collaboration and license agreement entered into in January 2011, as amended. GSK terminated the 
agreement without cause, and in accordance with the terms of the agreement and the notice of termination, the 
termination will be effective on March 16, 2022, or the GSK Agreement Termination Effective Date. The agreement 
provided that the parties would discover, develop and commercialize novel small molecule histone 
methyltransferase, or HMT, inhibitors directed to available targets from our product platform. Under the terms of the 
agreement, we granted GSK exclusive, worldwide license rights to HMT inhibitors directed to three targets. As part 
of the collaboration, we agreed to provide research and development services related to the licensed targets pursuant 
to agreed-upon research plans during a research term that ended January 8, 2015. We completed substantially all 
research obligations under the agreement by the end of the first quarter of 2015 and completed the transfer of the 
remaining data and material for these programs to GSK in the second quarter of 2015. GSK was then responsible for 
all future development and commercialization. Subsequent to a GSK strategic portfolio prioritization, we received 
notice in October 2017 that GSK terminated the agreement with respect to the third target, effective December 31, 
2017, which returned all rights to that target to us. The two other targets, PRMT5 and PRMT1, continued to be 
subject to the agreement and were not impacted by the termination with respect to the third target. As a result of the 
termination of the agreement, as of the GSK Agreement Termination Effective Date, the license rights granted by us 
to GSK will terminate, GSK will cease to accrue any financial obligations to us and we will be entitled to pursue the 
PRMT5 and PRMT1 targets in all fields worldwide without further obligation to GSK.
Companion Diagnostics 
Roche Sequencing Solutions 
In December 2012, Eisai and we entered into a companion diagnostics agreement with Roche Molecular under 
which Eisai and we engaged Roche Molecular to develop a companion diagnostic to identify patients who possess 
certain activating mutations of EZH2. In October 2013, this agreement was amended to include additional mutations 
in EZH2. The development costs due under the amended agreement with Roche Molecular were the responsibility of 
Eisai until the execution of the amended and restated collaboration and license agreement with Eisai in March 2015, 
at which time we assumed responsibility for the remaining development costs due under the agreement. In 
December 2015, we and Eisai entered into a second amendment to the companion diagnostics agreement with Roche 
Molecular. The agreement was further amended in March 2018. Under the amended agreement, we were responsible 
for remaining development costs of $10.4 million due under the agreement as of March 2018 and Eisai agreed to 
reimburse us $0.9 million of this amount related to a regulatory milestone for Japan, which Eisai paid to us in the 
fourth quarter of 2020. In July 2019, we entered into a fourth amendment to the companion diagnostics agreement. 
Under the amended agreement, we and Roche Molecular agreed to divide a $1.0 million regulatory milestone for the 
United States into two separate milestone payments, of which $0.5 million was paid by us as part of the signed 

19
amendment, and the remaining $0.5 million was paid by us in December 2019 upon the satisfaction of certain 
conditions set forth in the fourth amendment to the companion diagnostics agreement. As part of this fourth 
amendment, Roche Molecular also assigned all of its rights and obligations under the companion diagnostics 
agreement to Roche Sequencing Solutions, or RSS, effective as of January 1, 2020. As of December 31, 2021, we 
are responsible for the remaining development costs of $1.0 million due under the agreement. In addition, we paid 
$1.0 million for the achievement of a development milestone in the fourth quarter of 2020. 
Under the agreement with RSS, RSS is obligated to use commercially reasonable efforts to develop and to make 
commercially available the companion diagnostic kit. RSS has exclusive rights to commercialize the companion 
diagnostic kit developed pursuant to this agreement. On June 18, 2020 the FDA approved the companion diagnostic 
kit that is intended to identify FL patients with an EZH2 mutation for treatment with tazemetostat.
The agreement with RSS will expire when we and Eisai are no longer developing or commercializing tazemetostat. 
We and Eisai may terminate the agreement by giving RSS 90 days’ written notice if we and Eisai discontinue 
development and commercialization of tazemetostat or determine, in conjunction with RSS, that the companion 
diagnostic is not needed for use with tazemetostat. Any party may also terminate the agreement in the event of a 
material breach by any other party, in the event of material changes in circumstances that are contrary to key 
assumptions specified in the agreement or in the event of specified bankruptcy or similar circumstances. Under 
specified termination circumstances, RSS may become entitled to specified termination fees. 
Intellectual Property 
We strive to protect the proprietary compounds and technologies that we believe are important to our business, 
including seeking and maintaining patent protection intended to cover the composition of matter of our product 
candidates, their methods of use, related technologies, diagnostics and other inventions. Our patent portfolio is 
currently composed of over 300 issued patents and allowed patent applications and over 550 pending patent 
applications in the major pharmaceutical markets, that we own as well as license from other parties. In addition to 
patent protection, we also rely on trade secrets and careful monitoring of our proprietary information to protect 
aspects of our business that are not amenable to, or that we do not consider appropriate for, patent protection. 
Our success will depend significantly on our ability to obtain and maintain patent and other proprietary protection 
for commercially important technology, inventions and know-how related to our business, defend and enforce our 
patents, maintain our licenses to use intellectual property owned by third parties, preserve the confidentiality of our 
trade secrets and operate without infringing the valid and enforceable patents and other proprietary rights of third 
parties. We also rely on know-how, continuing technological innovation and in-licensing opportunities to develop, 
strengthen, and maintain our proprietary position in the field of HMTs, as well as to develop a proprietary position 
for new target classes, such as HATs and helicases. 
We plan to continue to expand our intellectual property estate by filing patent applications directed to dosage forms, 
methods of treatment and additional CMP and HMT inhibitor compounds and their derivatives, and to other new 
target classes. Specifically, we seek patent protection in the United States and internationally for novel compositions 
of matter covering the compounds, the chemistries and processes for manufacturing these compounds and the use of 
these compounds in a variety of therapies. 
The patent portfolios for our most advanced programs are summarized below. 
EZH2. Our EZH2 patent portfolio includes U.S. Patent No. 8,410,088 covering the composition of matter of 
tazemetostat. This patent issued on April 2, 2013 and is expected to expire in 2032, not including extensions. Our 
EZH2 portfolio also includes 54 additional U.S. patents and more than 250 foreign patents, expected to expire 
between 2031 and 2037, not including extensions. The claims of these patents cover the composition of matter of 
EZH2 inhibitor compounds and various methods of their making and use. Patent applications in the same families as 
these patents are pending in a variety of worldwide jurisdictions, including the United States. The EZH2 program 
portfolio encompasses more than 40 patent families with pending patent applications relating to compositions of 
matter and methods of making and use of EZH2 inhibitors. The patent families in this portfolio are in various stages 
of prosecution and include patent applications filed in a variety of worldwide jurisdictions, including the United 
States; Patent Cooperation Treaty, or PCT, applications that are eligible for filing in most worldwide jurisdictions, 

20
including the United States, and at least one U.S. provisional application that may be used as the basis for non-
provisional U.S. applications, PCT applications and other national filings worldwide. Our patent applications in the 
EZH2 portfolio, if issued, would be expected to expire between 2031 and 2041, not including extensions. 
SETD2. Our SETD2 patent portfolio includes six patent families directed to various product candidates and methods 
of use, with applications filed in the United States and internationally. Patents, if issued from currently pending 
applications in the SETD2 portfolio, are expected to expire between 2038 and 2042, not including extensions.
EHMT2. Our EHMT2 patent portfolio includes more than eight patent families directed to various product 
candidates and methods of use, with applications filed in the United States and internationally. Patents, if issued 
from currently pending applications in the EHMT2 portfolio, are expected to expire between 2037 and 2038, not 
including extensions.
Other Targets. We also have patent portfolios directed to targets other than EZH2, SETD2 and EHMT2, including 
the HMT targets DOT1L, PRMT1, PRMT3, CARM1 (also known as PRMT4), PRMT5, PRMT6, PRMT8, SMYD2 
and SMYD3. These patent portfolios have more than 35 patent families directed to various product candidates with 
applications filed in the United States, PCT applications that are eligible for filing in most worldwide jurisdictions, 
including the United States, and U.S. provisional applications that may be used to establish non-provisional U.S. 
applications, PCT applications and other national filings worldwide. Patents, if issued in these portfolios are 
expected to expire between 2033 and 2041. We have more than 20 granted U.S. patents that cover PRMT5 inhibitors 
and their methods of use. These patents are expected to expire in 2033, not including extensions. 
The term of individual patents depends upon the legal term of the patents in the countries in which they are obtained. 
In most countries in which we file, the patent term is 20 years from the earliest date of filing a non-provisional 
patent application. 
In the United States, the patent term of a patent that covers an FDA-approved drug may also be eligible for patent 
term extension, which permits patent term restoration as compensation for the patent term lost during the FDA 
regulatory review process. The Hatch-Waxman Act permits a patent term extension of up to five years beyond the 
expiration of the patent. The length of the patent term extension is related to the length of time the drug is under 
regulatory review. Patent extension cannot extend the remaining term of a patent beyond a total of 14 years from the 
date of product approval and only one patent applicable to an approved drug may be extended. Similar provisions 
are available in Europe and other non-United States jurisdictions to extend the term of a patent that covers an 
approved drug. We have applied for patent term extension on a patent that covers the TAZVERIK drug substance 
(tazemetostat) based on the regulatory review of TAZVERIK for the treatment of adult and pediatric patients aged 
16 years and older with metastatic or locally advanced ES not eligible for complete resection. In the future, if and 
when any additional pharmaceutical products receive FDA approval, we expect to apply for patent term extensions 
on patents covering those products. We intend to seek patent term extensions to any of our issued patents in any 
jurisdiction where these are available, however there is no guarantee that the applicable authorities, including the 
FDA in the United States, will agree with our assessment of whether such extensions should be granted, and even if 
granted, the length of such extensions. 
We also rely on trade secret protection for our confidential and proprietary information. Although we take steps to 
protect our proprietary information and trade secrets, including through contractual means with our employees and 
consultants, third parties may independently develop substantially equivalent proprietary information and techniques 
or otherwise gain access to our trade secrets or disclose our technology. Thus, we may not be able to meaningfully 
protect our trade secrets. It is our policy to require our employees, consultants, outside scientific collaborators, 
sponsored researchers and other advisors to execute confidentiality agreements upon the commencement of 
employment or consulting relationships with us. These agreements provide that all confidential information 
concerning our business or financial affairs developed or made known to the individual during the course of the 
individual’s relationship with us is to be kept confidential and not disclosed to third parties except in specific 
circumstances. In the case of employees, the agreements also provide that all inventions conceived by the individual, 
and which are related to our current or planned business or research and development or made during normal 
working hours, on our premises or using our equipment or proprietary information, are our exclusive property. 

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Manufacturing 
We do not have any manufacturing facilities and currently rely, and expect to continue to rely, on third parties for 
the manufacture of our development-stage product candidates including EZM0414 as well as our commercial 
product, tazemetostat. We have entered into clinical and commercial supply agreements with contract manufacturers 
for the clinical development and commercialization of tazemetostat. 
Tazemetostat and EZM0414 are small molecules and are manufactured in third-party facilities that are equipped, 
staffed, and experienced in the manufacture of such pharmaceutical products. All such facilities have successful 
track-records manufacturing products for the United States, European Union, and rest of world markets, meeting 
regulatory and compliance requirements as appropriate. 
We expect that any product candidates that we may develop will be small molecules that may be produced cost-
effectively at contract manufacturing facilities. 
We rely on third parties for the manufacture of any diagnostics we may need or if required and may continue to 
enter into similar agreements for the manufacture of other diagnostics. We are currently collaborating with RSS for 
a diagnostic for its use with tazemetostat. As described above, under the agreement with RSS, RSS is obligated to 
use commercially reasonable efforts to develop and to make commercially available the companion diagnostic kit. 
In June 2020 the FDA approved the companion diagnostic kit that is intended to identify follicular lymphoma 
patients with an EZH2 mutation for treatment with tazemetostat. 
Commercialization 
TAZVERIK is available to eligible patients in the United States via a specialty distribution network. Through this 
specialty distribution network, we sell TAZVERIK principally to a limited number of specialty pharmacies, which 
dispense the product directly to patients, and specialty distributors, which in turn sell the product to hospital 
pharmacies and community practice pharmacies for the treatment of patients. To commercialize TAZVERIK for the 
ES and FL indications in the United States, we have built a focused field presence and marketing capabilities. This 
includes an efficiently sized field-based organization focused on Academic Centers of Excellence, Integrated 
Delivery Networks (IDNs) and targeted community clinics. This includes an efficiently sized field-based 
organization of approximately 45 individuals.
We are pursuing three strategic commercialization imperatives that we believe are integral to success for 
TAZVERIK in the United States:

ensure eligible ES and FL patients have access to TAZVERIK by educating healthcare providers, 
patients and payers on the TAZVERIK data in approved indications,

ensure that TAZVERIK is readily accessible by physicians as an essential treatment option for each 
labeled indication through incorporation into systems of care, consistent with the label and guidelines, 
and 

ensure our company sponsored programs for patients and healthcare providers (EpizymeNOW and 
EZH2NowSM) support a positive experience when TAZVERIK is prescribed. EpizymeNOW facilitates 
patient access to new TAZVERIK prescriptions, and the EZH2Now program provides access to EZH2 
testing free of charge to patients with FL for providers who wish to know the mutation status of their 
patients.
Subject to receiving marketing approvals for additional indications or products, we expect to use our existing sales 
organization in the United States or to seek to expand our sales organization in the United States to sell our products. 
We believe that such an organization will be able to address the hematologists and oncologists who are the key 
specialists in treating the patient populations for which tazemetostat is currently approved and for which it is being 
developed and for which any future product candidates may be developed. Outside the United States, we may 
choose to enter into distribution and other marketing arrangements with third parties for any of our product 
candidates that obtain marketing approval, or may choose to commercialize our products in certain markets, 

22
depending upon many factors, including the target market size, availability of reimbursement, and our financial 
resources at the time. 
We own the global development and commercialization rights to tazemetostat outside of Japan and greater China. 
Eisai holds the rights to develop and commercialize tazemetostat in Japan. On August 7, 2021, pursuant to a license 
agreement with HutchMed, we granted a license to HutchMed for the co-exclusive (with us) development and 
exclusive commercialization of tazemetostat, either as monotherapy or as a part of combinations with other 
therapies, including HutchMed proprietary compounds, agreed by us and HutchMed for the treatment of ES, FL and 
DLBCL in humans, and any additional indications agreed to by us and HutchMed in the HutchMed Territory. For 
other geographies outside the United States, we are evaluating the most efficient path to reaching patients, including 
through leveraging existing and identifying new strategic collaborations that can contribute to our ability to rapidly 
develop and commercialize tazemetostat outside of the United States.
We expect that our collaborators for any companion or complementary diagnostics we may develop in the future for 
use with our therapeutic products will hold the commercial rights to these diagnostic products, as is the case for our 
collaboration with RSS. We expect to coordinate closely with any diagnostic collaborators in connection with the 
marketing and sale of any related therapeutic products. 
Competition 
The biotechnology and pharmaceutical industries are characterized by rapidly advancing technologies, intense 
competition and a strong emphasis on proprietary products. While we believe that our technology, knowledge, 
experience and scientific resources provide us with competitive advantages, we face potential competition from 
many different sources, including major pharmaceutical, specialty pharmaceutical and biotechnology companies, 
academic institutions and governmental agencies and public and private research institutions. Any product 
candidates that we successfully develop and commercialize will compete with existing therapies and new therapies 
that may become available in the future. 
There are a large number of companies developing or marketing treatments for cancer, including many major 
pharmaceutical and biotechnology companies. Companies that are developing new epigenetic treatments for cancer 
that target histone methyltransferases, or HMTs, and protein arginine methyltransferases, or PRMTs, include GSK, 
Johnson & Johnson, Pfizer, Inc., Daiichi Sankyo Company Limited, and MorphoSys AG. Further, companies which 
are known to have EZH2 inhibitor programs or related programs include: Constellation Pharmaceuticals, developing 
an EZH2 inhibitor CPI-0209, Phase 1/2, solid tumors and lymphoma, including DLBCL, Novartis AG, developing 
an EED inhibitor which indirectly blocks EZH2 (MAK683, Phase 1/2, advanced malignancies), Daiichi Sankyo, 
developing a EZH1/EZH2 dual inhibitor (valemetostat, DS-3201, Phase 1, relapsed or refractory non-Hodgkin 
lymphomas, AML, ALL as well as Phase 2 for small cell lung cancer), and Pfizer, developing EZH2 inhibitor PF-
06821497, Phase 1, relapsed or refractory SCLC, castration-resistant prostate cancer, FL and diffuse large B-cell 
lymphoma. In addition, many companies are developing cancer therapeutics that work by targeting epigenetic 
mechanisms other than HMTs, and some including Celgene (now part of Bristol-Myers Squibb), Merck & Co., Inc., 
Secura Bio, Spectrum Pharmaceuticals Otsuka Pharmaceuticals, Foghorn Therapeutics, Forma Therapeutics and 
CellCentric are now marketing cancer treatments that work by targeting epigenetic mechanisms other than HMTs. 
Many of the companies against which we are competing or against which we may compete in the future have 
significantly greater financial resources and expertise in research and development, manufacturing, preclinical 
testing, conducting clinical trials, obtaining regulatory approvals and marketing approved products than we do. 
Mergers and acquisitions in the pharmaceutical, biotechnology and diagnostic industries may result in even more 
resources being concentrated among a smaller number of our competitors. Smaller or early stage companies may 
also prove to be significant competitors, particularly through collaborative arrangements with large and established 
companies. These competitors also compete with us in recruiting and retaining qualified scientific and management 
personnel and establishing clinical trial sites and patient registration for clinical trials, as well as in acquiring 
technologies complementary to, or necessary for, our programs. 
The key competitive factors affecting the success of all of our therapeutic product candidates, if approved, are likely 
to be their efficacy, safety, convenience, price, the effectiveness of companion diagnostics in guiding the use of 

23
related therapeutics, the level of generic competition and the availability of reimbursement from government and 
other third-party payors. 
Our commercial opportunity could be reduced or eliminated if our competitors develop and commercialize products 
that are safer, more effective, have fewer or less severe side effects, are more convenient or are less expensive than 
any products that we may develop. Our competitors also may obtain FDA or other regulatory approval for their 
products more rapidly than we may obtain approval for ours, which could result in our competitors establishing a 
strong market position before we are able to enter the market. In addition, our ability to compete may be affected in 
many cases by insurers or other third-party payors seeking to encourage the use of generic products. Generic 
products that broadly address these indications are currently on the market for the indications that we are pursuing, 
and additional products are expected to become available on a generic basis over the coming years. If our product 
candidates achieve marketing approval, we expect that they will be priced at a significant premium over competitive 
generic products. 
The most common methods of treating patients with cancer are surgery, radiation and drug therapy. There are a 
number of products in late-stage clinical development to treat cancer. These products in development may provide 
efficacy, safety, convenience and other benefits that are not provided by currently marketed therapies. As a result, 
they may provide significant competition for any of our product candidates for which we obtain marketing approval. 
Tazemetostat. The most common treatments for FL are chemotherapies, usually combined with the monoclonal 
antibody Rituxan, or Gazyva, which is an antibody that acts against the same target as Rituxan, CD20. While 
Rituxan and a number of other widely used anti-cancer agents are labeled broadly for follicular lymphoma, no 
therapies are approved specifically for the treatment of tumors associated with EZH2 activating mutations. There are 
a number of companies currently evaluating investigational agents in the relapsed and refractory follicular 
lymphoma patient setting.
In the relapsed and refractory follicular lymphoma patient setting, both current and near-term competition exists. 
Current competition includes CD20 combinations, several PI3K inhibitors, and CAR-T therapies. However, 
recently, two companies have announced that there have been voluntary withdrawals of accelerated approvals for FL 
indications for two PI3K inhibitors, Zydelig (idelalisib), and Copiktra (duvelisib) in the U.S. market. Additionally, 
parsaclisib’s NDA has been voluntarily withdrawn for the treatment of patients with relapsed/refractory FL. Near-
term competition includes companies currently evaluating investigational agents with varying mechanisms of action, 
with a CAR-T therapy (KYMRIAH) and a PI3K inhibitor/CD20 combination (Aliqopa (copanlisib) + rituximab) 
currently undergoing review with the FDA. In the first quarter of 2021, Kite Pharma, a subsidiary of Gilead 
Sciences, received FDA approval for its CAR-T therapy, YESCARTA, for the treatment of relapsed or refractory FL 
patients. Novartis is also developing its CAR-T therapy, KYMRIAH, for relapsed or refractory FL patients. In the 
third quarter of 2021 the FDA accepted Novartis’ Supplemental Biologics License Application for KYMRIAH in 
adult patients with relapsed or refractory FL after two prior lines of treatment. The EMA also accepted Novartis’ 
Type II Variation for KYMRIAH in adult patients with relapsed or refractory FL after two prior lines of treatment in 
the third quarter of 2021. KYMRIAH is also undergoing priority review by the FDA for relapsed or refractory FL 
patients. The bispecific antibody furthest along in development in relapsed or refractory FL is Roche’s CD3/CD20 
bispecific mosunetuzumab.
Other than TAZVERIK, there are no therapies which have been approved specifically for the treatment of 
epithelioid sarcoma. Epithelioid sarcoma, an INI1-negative tumor, is typically treated with surgical resection when it 
presents as localized disease. When epithelioid sarcoma recurs or metastasizes, it may be treated with systemic 
chemotherapy or investigational agents because, other than TAZVERIK, there are no approved systemic therapies 
specifically indicated for this disease. To the best of our knowledge there are no competitive products in 
development specifically for epithelioid sarcoma. However, we are aware of several clinical trials run by 
competitors that recruit patients with soft tissue sarcoma, which is inclusive of epithelioid sarcoma.
EZM0414. Our current intention for EZM0414, through our SET-101 clinical trial, is to focus on patients with 
t(4;14) multiple myeloma and non t(4;14) multiple myeloma once we reach the Phase 1b expansion portion of the 
trial. However, based on dose optimization data from the multiple myeloma and DLBCL patients in the Phase 1 
dose escalation portion of the trial, we may initiate a third patient cohort in DLBCL in the Phase 1b.

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The most common treatments of multiple myeloma include ImiD (include Revlimid (lenalidomide), Pomalyst 
(pomalidomide), and Thalidomide (thalomid)), proteasome inhibitors (including Velcade (bortezomib), Kyprolis 
(xarfilzomib), and Ninlaro (ixazomib)), and anti-CD38 mAb (including Darzalex (daratumumab) and Sarclisa 
(isatuximab-irfc)) combinations. Current therapies for the relapsed or refractory population also include BCMA 
targeting CAR-Ts and ADCs. The multiple myeloma pipeline is robust, and includes BCMA CAR-T therapies, 
bispecific antibodies, BiTEs, and CELMoDs. Additionally, there are assets in development for high risk MM and 
the t(4;14) subpopulation, including K36’s MMSET inhibitor KTX-1001.
For DLBCL, the most common treatments are chemotherapies, often in combination with the monoclonal antibody 
Rituxan (rituximab) as well as autologous stem cell transplants. In the relapsed or refractory patient setting, current 
therapies include CAR-T therapies (Kymriah (tisagenlecleucel), Yescarta (axicabtagene ciloleucel), Breyanzi 
(lisocabtagene maraleucel)), a CD19 mAb (Monjuvi (tafasitamab)), and ADCs (Policy (polatuzumab vedotin) and 
Zynlonta (loncastuximab tesirine)). DLBCL pipeline therapies include bispecific antibodies, ADCs, and CAR-T 
therapies. 
While there are many assets in development for both multiple myeloma and DLBCL including those with novel 
mechanisms of action, other than EZM0414, there are no therapies in development that are SETD2 inhibitors.
Government Regulation and Product Approval 
Government authorities in the United States, at the federal, state and local level, and in other countries and foreign 
jurisdictions, including the European Union, extensively regulate, among other things, the research, development, 
testing, manufacture, quality control, packaging, storage, record-keeping, labeling, advertising, promotion, 
distribution, marketing, pricing, reimbursement, import and export of pharmaceutical products such as those we are 
developing. The processes for obtaining regulatory approvals in the United States and in foreign countries and 
jurisdictions, along with subsequent compliance with applicable statutes and regulations, require the expenditure of 
substantial time and financial resources. 
United States Government Regulation 
In the United States, the FDA regulates drugs under the Federal Food, Drug, and Cosmetic Act, or FDCA, and its 
implementing regulations. It is the responsibility of the company seeking to market a drug to test it and submit 
evidence that the drug is safe and effective. Failure to comply with applicable United States regulatory requirements 
at any time during the product development process, approval process or after approval, may subject an applicant to 
a variety of administrative or judicial sanctions, such as the FDA’s refusal to approve pending NDAs, withdrawal of 
an approval, imposition of a clinical hold, issuance of warning or untitled letters, product recalls, product seizures, 
total or partial suspension of production or distribution, injunctions, fines, refusals of government contracts, 
restitution, disgorgement or civil or criminal penalties. 
The process required by the FDA before a drug may be marketed in the United States generally involves the 
following: 

completion of preclinical laboratory tests and animal studies in compliance with the FDA’s good 
laboratory practice regulations; 

design of a clinical protocol and submission to the FDA of an IND which must become effective before 
human clinical trials may begin; 

manufacture of drug substance and drug product to support clinical trials in compliance with FDA’s 
cGMP regulations;

approval by an independent institutional review board, or IRB, at each clinical site before each trial may 
be initiated; 

performance of human clinical trials, including adequate and well-controlled clinical trials, in 
accordance with good clinical practices, or GCP, to establish the safety and efficacy of the proposed 
drug product for each indication; 

25

submission to the FDA of an NDA or sNDA requesting marketing approval for one or more proposed 
indications; 

satisfactory completion of an FDA advisory committee review, if applicable; 

satisfactory completion of an FDA inspection of the manufacturing facility or facilities at which the 
product is produced to assess compliance with current good manufacturing practices, or cGMP, and to 
assure that the facilities, methods and controls are adequate to preserve the drug’s identity, strength, 
quality and purity; 

satisfactory completion of an FDA inspection of selected clinical sites and/or clinical CROs to 
determine GCP compliance and the integrity of the clinical data submitted in support of the application;

satisfactory completion of an FDA inspection of the NDA sponsor to assess compliance with GxPs;

payment of user fees per published Prescription Drug User Fee Act, or PDUFA, guidelines for that year, 
if applicable; 

FDA review and approval of the NDA or sNDA; and 

commitment to comply with any post-approval requirements, including the potential requirements, to 
implement a Risk Evaluation and Mitigation Strategy, or REMS, and the potential requirement to 
conduct post-approval studies. 
Preclinical Studies and an IND. Before an applicant begins testing a compound with potential therapeutic value in 
humans, the product candidate enters the preclinical testing stage. Preclinical studies include laboratory evaluation 
of product chemistry, toxicity and formulation, as well as animal studies to assess its potential safety and 
effectiveness. The conduct of the preclinical tests and formulation of the compounds for testing must comply with 
federal regulations and requirements, including Good Laboratory Practices regulations and standards and the United 
States Department of Agriculture’s Animal Welfare Act, if applicable.
An IND sponsor must submit the results of the preclinical tests, together with manufacturing information, analytical 
data and any available clinical data or literature, among other things, to the FDA as part of an IND. An IND is an 
exemption from the FDCA that allows an unapproved product candidate to be shipped in interstate commerce for 
use in an investigational clinical trial and a request for FDA authorization to administer such investigational product 
to humans. An IND automatically becomes effective 30 days after submission and receipt by the FDA unless, before 
that time, the FDA either provides a “safe to proceed” letter or raises concerns or questions related to one or more 
proposed clinical trials and places the clinical trial on a clinical hold or partial hold. In such a case, the IND sponsor 
and the FDA must resolve any outstanding concerns before the clinical trial can begin. As a result, submission of an 
IND may not result in the FDA allowing a clinical trial to commence. Following commencement of a clinical trial 
under an IND, the FDA may also place a clinical hold or partial clinical hold on a trial.
Clinical Trials. Clinical trials involve the administration of the investigational new drug to human subjects under the 
supervision of qualified investigators in accordance with GCP requirements, which include the requirement that all 
research subjects provide their informed consent in writing for their participation in any clinical trial. Clinical trials 
are conducted under protocols detailing, among other things, the objectives of the trial, the parameters to be used in 
monitoring safety and the efficacy criteria to be evaluated, if appropriate. A protocol for each clinical trial and any 
subsequent protocol amendments must be submitted to the FDA as part of the IND. In addition, an IRB at each 
institution participating in the clinical trial must review and approve the protocol for any clinical trial before it 
commences at that institution, and the IRB must continue to oversee the clinical trial while it is being conducted. 
Additionally, some trials are overseen by an independent group of qualified experts organized by the trial sponsor, 
often known as a data safety monitoring board or committee, or DSMB. 
Human clinical trials are typically conducted in four sequential phases, which may overlap or be combined. In Phase 
1, the candidate drug is initially introduced into healthy human subjects or patients with the target disease or 
condition and tested for safety, dosage tolerance, absorption, metabolism, distribution, excretion and, if possible, to 
gain an initial indication of its effectiveness. In Phase 2, the investigational drug typically is administered to a 
limited patient population to identify possible adverse effects and safety risks, to preliminarily evaluate the efficacy 
of the product for specific targeted diseases and to determine dosage tolerance and optimal dosage. In Phase 3, the 

26
candidate drug is administered to an expanded patient population, generally at geographically dispersed clinical trial 
sites, in well-controlled clinical trials to generate enough data to statistically evaluate the efficacy and safety of the 
product for approval, to establish the overall risk-benefit profile of the product and to provide adequate information 
for the labeling of the product. In Phase 4, post-approval studies may be conducted to gain additional experience 
from the treatment of patients in the intended therapeutic indication. A clinical trial may combine the elements of 
more than one phase and a company’s designation of a clinical trial as a particular phase is not necessarily indicative 
that the study will be sufficient to satisfy FDA requirements.
Progress reports detailing the results of the clinical trials must be submitted at least annually to the FDA and more 
frequently if serious adverse events occur. Clinical trials may not be completed successfully within any specified 
period, or at all. Furthermore, the FDA or the sponsor may suspend or terminate a clinical trial at any time on 
various grounds, including a finding that the research subjects are being exposed to an unacceptable health risk. 
Similarly, an IRB can suspend or terminate approval of a clinical trial at its institution if the clinical trial is not being 
conducted in accordance with the IRB’s requirements or if the drug has been associated with unexpected serious 
harm to patients. 
In general, the FDA accepts foreign safety and efficacy studies that were not conducted under an IND provided that 
they are well designed, well conducted, performed by qualified investigators, and conducted in accordance with 
ethical principles acceptable to the international community. The conduct of these studies must meet at least 
minimum standards for assuring human subject protection. Therefore, for studies submitted in support of an NDA 
that were conducted outside the United States and not under an IND, the agency requires demonstration that such 
studies were conducted in accordance with GCP, including receiving approval by an independent ethics committee, 
or IEC, and seeking and receiving informed consent from subjects. 
In August 2018, the FDA released a draft guidance entitled “Expansion Cohorts: Use in First-In-Human Clinical 
Trials to Expedite Development of Oncology Drugs and Biologics,” which outlines how sponsors can utilize an 
adaptive trial design in the early stages of oncology product development (i.e., the first-in-human clinical trial) to 
compress the traditional three phases of trials into one continuous trial called an expansion cohort trial. Information 
to support the design of individual expansion cohorts are included in IND applications and assessed by the FDA. 
Expansion cohort trials can potentially bring efficiency to product development and reduce developmental costs and 
time. 
Sponsors of clinical trials are required to register and disclose certain clinical trial information on a public registry 
(clinicaltrials.gov) maintained by the U.S. National Institutes of Health, or NIH. Both NIH and the FDA have 
recently signaled the government’s willingness to begin enforcing those requirements against non-compliant clinical 
trial sponsors.
Expanded Access to an Investigational Drug for Treatment Use. 
Expanded access, sometimes called “compassionate use,” is the use of investigational new drug products outside of 
clinical trials to treat patients with serious or immediately life-threatening diseases or conditions when there are no 
comparable or satisfactory alternative treatment options. The rules and regulations related to expanded access are 
intended to improve access to investigational drugs for patients who may benefit from investigational therapies who 
do not otherwise qualify for an ongoing clinical trial. FDA regulations allow access to investigational drugs under an 
IND by the company or the treating physician for treatment purposes on a case-by-case basis for: individual patients 
(single-patient IND applications for treatment in emergency settings and non-emergency settings); intermediate-size 
patient populations; and larger populations for use of the drug under a treatment protocol or Treatment IND 
Application. 
When considering an IND application for expanded access to an investigational product with the purpose of treating 
a patient or a group of patients, the sponsor and treating physicians or investigators will determine suitability when 
all of the following criteria apply: patient(s) have a serious or immediately life-threatening disease or condition, and 
there is no comparable or satisfactory alternative therapy to diagnose, monitor, or treat the disease or condition; the 
potential patient benefit justifies the potential risks of the treatment and the potential risks are not unreasonable in 
the context or condition to be treated; and the expanded use of the investigational drug for the requested treatment 

27
will not interfere initiation, conduct, or completion of clinical investigations that could support marketing approval 
of the product or otherwise compromise the potential development of the product.
There is no obligation for a sponsor to make its investigational products available for expanded access, but sponsors 
are required to make their expanded access policies publicly available upon the earlier of initiation of a Phase 2 or 
Phase 3 study; or 15 days after the drug or biologic receives designation as a breakthrough therapy, fast track 
product, or regenerative medicine advanced therapy. 
In addition to and separate from expanded access, on May 30, 2018, the Right to Try Act, was signed into law. The 
law, among other things, provides a federal framework for certain patients to access certain investigational new drug 
products that have completed a Phase 1 clinical trial and that are undergoing investigation for FDA approval. Under 
certain circumstances, eligible patients can seek treatment without enrolling in clinical trials and without obtaining 
FDA permission under the expanded access program. There is no obligation for a drug manufacturer to make its 
drug products available to eligible patients as a result of the Right to Try Act, but the manufacturer must develop an 
internal policy and respond to patient requests according to that policy. 
Pediatric Studies. Under the Pediatric Research Equity Act, or PREA, an NDA or supplement to an NDA must 
contain data that are adequate to assess the safety and effectiveness of the drug for the claimed indications in all 
relevant pediatric subpopulations, and to support dosing and administration for each pediatric subpopulation for 
which the product is safe and effective. The FDA may, on its own initiative or at the request of the applicant, grant 
deferrals for submission of some or all pediatric data until after approval of the product for use in adults, or full or 
partial waivers from the pediatric data requirements. The FDA maintains a list of diseases that are exempt from 
PREA requirements due to low prevalence of disease in the pediatric population. Congress amended the FDA 
Reauthorization Act of 2017, or FDARA. Previously, drugs that had been granted orphan drug designation were 
exempt from the requirements of the Pediatric Research Equity Act. Under the amended section 505B, beginning on 
August 18, 2020, the submission of a pediatric assessment, waiver or deferral will be required for certain 
molecularly targeted cancer indications with the submission of an NDA application or supplement to an NDA 
application. FL qualifies for an automatic full pediatric waiver by the FDA because it rarely or never occurs in 
pediatric patients. 
The FDA requires that a sponsor who is planning to submit a marketing application for a drug or biological product 
that includes a new active ingredient, new indication, new dosage form, new dosing regimen or new route of 
administration submit an initial Pediatric Study Plan, or PSP, within sixty days of an end-of-phase 2 meeting or as 
may be agreed between the sponsor and FDA. The initial PSP must include an outline of the pediatric study or 
studies that the sponsor plans to conduct, including study objectives and design, age groups, relevant endpoints and 
statistical approach, or a justification for not including such detailed information, and any request for a deferral of 
pediatric assessments or a full or partial waiver of the requirement to provide data from pediatric studies along with 
supporting information. FDA and the sponsor must reach agreement on the PSP. A sponsor can submit amendments 
to an agreed-upon initial PSP at any time if changes to the pediatric plan need to be considered based on data 
collected from nonclinical studies, early phase clinical trials, or other clinical development programs.
Submission and Filing of an NDA. Assuming successful completion of the required clinical testing, the results of 
the preclinical and clinical studies, together with detailed information relating to the product’s chemistry, 
manufacture, controls and proposed labeling, among other things, are submitted to the FDA as part of an NDA 
requesting approval to market the product for one or more indications. Under federal law, the submission of most 
NDAs is subject to an application user fee, which for federal fiscal year 2022 is $3,117,218 for an application 
requiring clinical data. The sponsor of an approved NDA is also subject to an annual program fee, which for fiscal 
year 2022 is $369,413. Certain exceptions and waivers are available for some of these fees, such as an exception 
from the application fee for products with orphan drug designation and a waiver for certain small businesses. 
The FDA also may require submission of a REMS plan to mitigate any identified or suspected serious risks. The 
REMS plan could include medication guides, physician communication plans, assessment plans, and elements to 
assure safe use, such as restricted distribution methods, patient registries or other risk minimization tools. 
Under PDUFA guidelines that are currently in effect, the FDA has agreed to certain performance goals regarding the 
timing of its review and disposition of an application. The FDA conducts a preliminary review of all NDAs within 

28
the first 60 days after submission, before accepting them for filing, to determine whether they are sufficiently 
complete to permit substantive review. The FDA must inform the sponsor at that time or before whether the 
application is sufficiently complete to permit substantive review. In the event that the FDA determines that an 
application does not satisfy this standard, it will issue a Refuse to File, or RTF, determination to the applicant. The 
FDA may request additional information rather than accept an NDA for filing. In this event, the application must be 
resubmitted with the additional information. The resubmitted application is also subject to review before the FDA 
accepts it for filing. 
If the submission is accepted for filing, the FDA begins an in-depth substantive review. The FDA reviews an NDA 
to determine, among other things, whether the drug is safe and effective and whether the facility in which it is 
manufactured, processed, packaged or held meets standards designed to assure the product’s continued safety, 
quality and purity. Under the goals and policies agreed to by the FDA under PDUFA, the FDA has ten months from 
the filing date in which to complete its initial review of a standard application that is a new molecular entity, and six 
months from the filing date for an application with “priority review.” The review process may be extended by the 
FDA for three additional months to consider new information or in the case of a clarification provided by the 
sponsor to address an outstanding deficiency identified by the FDA following the original submission. Despite these 
review goals, it is not uncommon for FDA review of an application to extend beyond the PDUFA goal date.
In connection with its review of an NDA, the FDA typically will inspect the facility or facilities where the product is 
manufactured. The FDA will not approve an application unless it determines that the manufacturing processes and 
facilities are in compliance with cGMP requirements and are adequate to assure consistent production of the product 
within required specifications. Additionally, the FDA will typically inspect one or more clinical trial sites to assure 
compliance with GCPs, may inspect the clinical CRO(s) to assure compliance with GCPs, and the FDA may also 
perform a sponsor inspection.
The FDA has the option to refer questions regarding their review of a marketing application for a New Molecular 
Entity, or NME, to an external advisory committee. An advisory committee is a panel of independent experts, 
including clinicians and other scientific experts, that reviews, evaluates and provides a recommendation as to 
whether the application should be approved and under what conditions. The FDA uses approximately 50 advisory 
committees and panels to obtain independent expert advice on scientific, technical, and policy matters. The FDA is 
not bound by the recommendations of an advisory committee, but it considers such recommendations carefully 
when making decisions. 
Decisions on an NDA
The FDA reviews an application to determine, among other things, whether the product is safe and whether it is 
effective for its intended use(s), with the latter determination being made on the basis of substantial evidence. 
The FDA has interpreted this evidentiary standard to require at least two adequate and well-controlled clinical 
investigations to establish effectiveness of a new product. Under certain circumstances, however, the FDA has 
indicated that a single trial with certain characteristics and additional information may satisfy this standard. 
Ultimately, the FDA will determine whether the expected benefits of the drug product outweigh its potential risks to 
patients.
After evaluating the NDA and all related information, including the advisory committee recommendation, if any, 
and inspection reports regarding the manufacturing facilities and clinical trial sites, the FDA may issue a complete 
response letter or an approval letter. A complete response letter generally contains a statement of specific conditions 
that must be met in order to secure final approval of the NDA and may require additional clinical or preclinical 
testing in order for FDA to reconsider the application. Even with submission of this additional information, the FDA 
ultimately may decide that the application does not satisfy the regulatory criteria for approval. 
An approval letter authorizes commercial marketing of the drug with specific prescribing information for specific 
indications. Even if the FDA approves a product, it may limit the approved indications for use of the product, 
require that contraindications, warnings or precautions be included in the product labeling, including a boxed 
warning, require that post-approval studies, including Phase 4 clinical trials, be conducted to further assess a drug’s 
safety after approval, require testing and surveillance programs to monitor the product after commercialization, or 
impose other conditions, including distribution restrictions or other risk management mechanisms under a REMS 

29
which can materially affect the potential market and profitability of the product. The FDA may prevent or limit 
further marketing of a product based on the results of post-marketing studies or surveillance programs. After 
approval, some types of changes to the approved product, such as adding new indications, manufacturing changes, 
and additional labeling claims, are subject to further testing requirements and FDA review and approval. 
Orphan Drug Designation. Under the Orphan Drug Act, the FDA may grant orphan drug designation to a drug 
(including a biologic) intended to treat a rare disease or condition, which is generally a disease or condition that 
affects fewer than 200,000 individuals in the United States, or more than 200,000 individuals in the United States 
and for which there is no reasonable expectation that the cost of developing and making available in the United 
States a drug for this type of disease or condition will be recovered from sales in the United States for that drug. 
Orphan drug designation must be requested before submitting an NDA or biologics license application, or BLA. 
After the FDA grants orphan drug designation, the identity of the therapeutic agent and its potential orphan use are 
disclosed publicly by the FDA.
Orphan drug designation qualifies the sponsor of the drug for various development incentives. For example, a 
marketing application for a prescription drug product that has received orphan drug designation is not subject to a 
prescription drug user fee unless the application includes an indication other than for the rare disease or condition 
for which the drug was designated. Furthermore, federal law establishes certain tax credits designed to encourage 
the development of orphan drugs. With passage of the Tax Cuts and Jobs Act of 2017, that tax credit was halved 
from 50% to 25%. The granting of an orphan drug designation request does not alter the standard regulatory 
requirements and process for obtaining marketing approval. Safety and effectiveness of a drug must be established 
through adequate and well-controlled studies.
Special FDA Expedited Review and Approval Programs. The FDA has various programs, including Fast Track 
Designation, Accelerated Approval, Priority Review and Breakthrough Therapy Designation, that are intended to 
expedite or simplify the process for the development and FDA review of drugs that are intended for the treatment of 
serious or life threatening diseases or conditions and demonstrate the potential to address unmet medical needs. The 
purpose of these programs is to provide important new drugs to patients earlier than under standard FDA review 
procedures. Even if a product qualifies for one or more of these programs, the FDA may later decide that the product 
no longer meets the conditions for qualification or decide that the time period for FDA review or approval will not 
be shortened. None of these expedited programs changes the standards for approval but they may help expedite the 
development or approval process of product candidates.
Breakthrough Therapy Designation. Under the provisions of the Food and Drug Administration Safety and 
Innovation Act, or FDASIA, enacted in 2012, a sponsor can request designation of a product candidate as a 
“breakthrough therapy.” The FDA may grant breakthrough therapy designation to a drug that is intended, alone or in 
combination with one or more other drugs, to treat a serious or life-threatening disease or condition, and preliminary 
clinical evidence indicates that the drug may demonstrate substantial improvement over existing therapies on one or 
more clinically significant endpoints, such as substantial treatment effects observed early in clinical development. 
The FDA must take certain actions, such as holding timely meetings and providing advice, intended to expedite the 
development and review of an application for approval of a breakthrough therapy. For drugs and biologics that have 
been designated as breakthrough therapies, interaction and communication between the FDA and the sponsor of the 
trial can help to identify the most efficient path for clinical development while minimizing the number of patients 
placed in ineffective control regimens. Drugs designated as breakthrough therapies by the FDA are also eligible for 
accelerated approval. 
Fast Track Designation. To be eligible for a Fast Track Designation, the FDA must determine, based on the request 
of a sponsor, that a product is intended to treat a serious or life-threatening disease or condition and demonstrates the 
potential to address an unmet medical need. The FDA will determine that a product will fill an unmet medical need 
if it will provide a therapy where none exists or provide a therapy that may be potentially superior to existing 
therapy based on efficacy or safety factors. For Fast Track products, sponsors may have greater interactions with the 
FDA regarding drug development and may submit sections of a Fast Track product’s NDA on a rolling basis before 
the entire application is complete. 
Priority Review. The FDA may give a priority review designation to drugs that offer major advances in treatment, or 
provide a treatment where no adequate therapy exists. A priority review means that the goal for the FDA to review 

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an application is six months, rather than the standard review of ten months under current PDUFA guidelines. These 
six- and ten-month review periods are measured from the “filing” date rather than the receipt date for NDAs for new 
molecular entities, which typically adds approximately two months to the timeline for review and decision from the 
date of submission. Most products that are eligible for Fast Track designation are also likely to be considered 
appropriate to receive a priority review. 
Accelerated Approval. In addition, products studied for their safety and effectiveness in treating serious or life-
threatening illnesses and that provide meaningful therapeutic benefit over existing treatments may receive 
accelerated approval and may be approved on the basis of well-conducted clinical trials establishing that the drug 
product has an effect on a surrogate endpoint that is reasonably likely to predict clinical benefit, or on a clinical 
endpoint that can be measured earlier than irreversible morbidity or mortality, that is reasonably likely to predict an 
effect on irreversible morbidity or mortality or other clinical benefit, taking into account the severity, rarity or 
prevalence of the condition and the availability or lack of alternative treatments. As a condition of accelerated 
approval, the FDA may require a sponsor to perform post-marketing confirmatory study(ies) to verify and describe 
the predicted effect on irreversible morbidity or mortality or other clinical endpoints, and the drug may be subject to 
accelerated withdrawal procedures. Although a drug may be designated as “breakthrough” or “fast track”, the 
determination of accelerated approval is based on the clinical endpoint and not on the expeditious manner in which 
it is being developed. 
FDA Regulation of Companion Diagnostics. Safe and effective use of a drug may rely upon an in vitro companion 
diagnostic for use in selecting the patients that will be more likely to respond to the treatment. FDA officials have 
issued guidance that addresses issues critical to developing in vitro companion diagnostics, such as when the FDA 
will require that the diagnostic and the drug be approved simultaneously. The guidance issued in August 2014 states 
that if safe and effective use of a therapeutic product depends on an in vitro diagnostic, then the FDA generally will 
require approval or clearance of the diagnostic at the same time that the FDA approves the therapeutic product. In 
April 2020, the FDA issued additional guidance which describes considerations for the development and labeling of 
companion diagnostic devices to support the indicated uses of multiple drug or biological oncology products, when 
appropriate.
Under the FDCA, in vitro diagnostics, including companion diagnostics, are regulated as medical devices. The FDA 
generally requires that devices, or in vitro companion diagnostics, intended to select the patients who will respond to 
the cancer treatment to obtain Pre-Market Approval, or PMA, simultaneously with approval of the drug. Based on 
the guidance, and the FDA’s past treatment of companion diagnostics, the FDA will typically require PMA approval 
of one or more in vitro companion diagnostics to identify patient populations suitable for these cancer therapies. 
The PMA process, including the gathering of clinical and preclinical data and the submission to and review by the 
FDA involves a rigorous premarket review during which the applicant must prepare and provide the FDA with 
reasonable assurance of the device’s safety and effectiveness and information about the device and its components 
regarding, among other things, device design, manufacturing and labeling. PMA applications are subject to an 
application fee. For federal fiscal year 2021, the standard fee is $374,858 and the small business fee is $93,714. 
After a device is placed on the market, it remains subject to significant regulatory requirements. Medical devices 
may be marketed only for the uses and indications for which they are cleared or approved. Device manufacturers 
must also establish registration and device listings with the FDA. A medical device manufacturer’s manufacturing 
processes and those of its suppliers are required to comply with the applicable portions of the Quality System 
Regulation, or QSR, which cover the methods and documentation of the design, testing, production, processes, 
controls, quality assurance, labeling, packaging and shipping of medical devices. Domestic facility records and 
manufacturing processes are subject to periodic unscheduled inspections by the FDA. The FDA also may inspect 
foreign facilities that export products to the U.S.
Post-Approval Commitments and Requirements. Drugs manufactured or distributed pursuant to FDA approvals are 
subject to pervasive and continuing regulation by the FDA, including, among other things, requirements relating to 
recordkeeping, periodic reporting, product sampling and distribution, advertising and promotion and reporting of 
adverse experiences with the product. After approval, most changes to the approved product, such as adding new 
indications or other labeling claims are subject to prior FDA review and approval. There also are continuing, annual 

31
user fee requirements for any marketed products and the establishments at which such products are manufactured, as 
well as new application fees for supplemental applications with clinical data. 
The FDA may impose a number of post-approval requirements as a condition of approval of an NDA. For example, 
the FDA may require post-marketing testing, including Phase 4 clinical trials and surveillance to further assess and 
monitor the product’s safety and effectiveness after commercialization. 
In addition, drug manufacturers and other entities involved in the manufacture and distribution of approved drugs 
are required to register their establishments with the FDA and state agencies, and are subject to periodic 
unannounced inspections by the FDA and these state agencies for compliance with cGMP requirements. Changes to 
the manufacturing process are strictly regulated and often require prior FDA approval before being implemented. 
FDA regulations also require investigation and correction of any deviations from cGMP and impose reporting and 
documentation requirements upon the sponsor and any third-party manufacturers that the sponsor may decide to use. 
Accordingly, manufacturers must continue to expend time, money and effort in the area of production and quality 
control to maintain cGMP compliance. 
Once an approval is granted, the FDA may withdraw the approval if compliance with regulatory requirements and 
standards is not maintained or if problems occur after the product reaches the market. 
Later discovery of previously unknown problems with a product, including adverse events of unanticipated severity 
or frequency, or with manufacturing processes, or failure to comply with regulatory requirements, may result in 
mandatory revisions to the approved labeling to add new safety information; imposition of post-market studies or 
clinical trials to assess new safety risks; or imposition of distribution or other restrictions under a REMS program. 
Other potential consequences include, among other things: 

restrictions on the marketing or manufacturing of the product, complete withdrawal of the product from 
the market or product recalls; 

fines, warning letters or holds on post-approval clinical trials; 

refusal of the FDA to approve pending NDAs or supplements to approved NDAs, or suspension or 
revocation of product license approvals; 

product seizure or detention, or refusal to permit the import or export of products; or 

injunctions or the imposition of civil or criminal penalties. 
The FDA strictly regulates marketing, labeling, advertising and promotion of products that are placed on the market. 
Drugs may be promoted only for the approved indications and in accordance with the provisions of the approved 
label. The FDA and other agencies actively enforce the laws and regulations prohibiting the promotion of off label 
uses, and a company that is found to have improperly promoted off label uses may be subject to significant liability. 
If a company is found to have promoted off label uses, it may become subject to adverse public relations and 
administrative and judicial enforcement by the FDA, the Department of Justice, or the Office of the Inspector 
General of the Department of Health and Human Services, as well as state authorities. This could subject a company 
to a range of penalties that could have a significant commercial impact, including civil and criminal fines and 
agreements that materially restrict the manner in which a company promotes or distributes drug products. In 
September 2021, the FDA published final regulations which describe the types of evidence that the agency will 
consider in determining the intended use of a drug product.
In addition, the distribution of prescription pharmaceutical products is subject to the Prescription Drug Marketing 
Act, or PDMA, and its implementing regulations, as well as the Drug Supply Chain Security Act, or DSCA, which 
regulate the distribution and tracing of prescription drugs and prescription drug samples at the federal level, and set 
minimum standards for the regulation of drug distributors by the states. The PDMA, its implementing regulations 
and state laws limit the distribution of prescription pharmaceutical product samples, and the DSCA imposes 
requirements to ensure accountability in distribution and to identify and remove counterfeit and other illegitimate 
products from the market. 

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Federal and State Fraud and Abuse and Data Privacy and Security Laws and Regulations. In addition to FDA 
restrictions on marketing of pharmaceutical products, federal and state fraud and abuse laws restrict business 
practices in the biopharmaceutical industry. These laws include anti-kickback and false claims laws and regulations 
as well as data privacy and security laws and regulations. 
The federal Anti-Kickback Statute prohibits, among other things, knowingly and willfully offering, paying, 
soliciting or receiving remuneration to induce or in return for purchasing, leasing, ordering, or arranging for or 
recommending the purchase, lease, or order of any item or service reimbursable under Medicare, Medicaid or other 
federal healthcare programs. The term “remuneration” has been broadly interpreted to include anything of value. 
The Anti-Kickback Statute has been interpreted to apply to arrangements between pharmaceutical manufacturers on 
one hand and prescribers, purchasers, and formulary managers on the other. Although there are a number of 
statutory exemptions and regulatory safe harbors protecting some common activities from prosecution, the 
exemptions and safe harbors are drawn narrowly. Practices that involve remuneration that may be alleged to be 
intended to induce prescribing, purchases, or recommendations may be subject to scrutiny if they do not qualify for 
an exemption or safe harbor. Several courts have interpreted the statute’s intent requirement to mean that if any one 
purpose of an arrangement involving remuneration is to induce referrals of federal healthcare covered business, the 
statute has been violated. 
The reach of the Anti-Kickback Statute was also broadened by the Patient Protection and Affordable Care Act of 
2010, as amended by the Health Care and Education Reconciliation Act of 2010, or collectively PPACA, which, 
among other things, amended the intent requirement of the federal Anti-Kickback Statute such that a person or entity 
no longer needs to have actual knowledge of this statute or specific intent to violate it in order to have committed a 
violation. In addition, PPACA provides that the government may assert that a claim including items or services 
resulting from a violation of the federal Anti-Kickback Statute constitutes a false or fraudulent claim for purposes of 
the civil False Claims Act or the civil monetary penalties statute, which imposes penalties against any person who is 
determined to have presented or caused to be presented a claim to a federal health program that the person knows or 
should know is for an item or service that was not provided as claimed or is false or fraudulent. PPACA also created 
new federal requirements for reporting, by applicable manufacturers of covered drugs, payments and other transfers 
of value to physicians and teaching hospitals. 
The federal False Claims Act prohibits any person from knowingly presenting, or causing to be presented, a false 
claim for payment to the federal government or knowingly making, using, or causing to be made or used a false 
record or statement material to a false or fraudulent claim to the federal government. A claim includes “any request 
or demand” for money or property presented to the U.S. government. Several pharmaceutical and other healthcare 
companies have been prosecuted under these laws for allegedly providing free product to customers with the 
expectation that the customers would bill federal programs for the product. Other companies have been prosecuted 
for causing false claims to be submitted because of the companies’ marketing of products for unapproved, and thus 
non-reimbursable, uses. The federal Health Insurance Portability and Accountability Act of 1996, or HIPAA, 
created new federal criminal statutes that prohibit knowingly and willfully executing a scheme to defraud any 
healthcare benefit program, including private third-party payors and knowingly and willfully falsifying, concealing 
or covering up a material fact or making any materially false, fictitious or fraudulent statement in connection with 
the delivery of or payment for healthcare benefits, items or services. Also, many states have similar fraud and abuse 
statutes or regulations that apply to items and services reimbursed under Medicaid and other state programs, or, in 
several states, apply regardless of the payor. 
We may also be subject to data privacy and security regulation by both the federal government and the states in 
which we conduct our business. HIPAA, as amended by the Health Information Technology and Clinical Health 
Act, or HITECH, and its implementing regulations, imposes specified requirements relating to the privacy, security 
and transmission of individually identifiable health information. Among other things, HITECH makes HIPAA’s 
privacy and security standards directly applicable to “business associates,” defined as independent contractors or 
agents of covered entities that receive or obtain protected health information in connection with providing a service 
on behalf of a covered entity. HITECH also increased the civil and criminal penalties that may be imposed against 
covered entities, business associates and possibly other persons, and gave state attorneys general new authority to 
file civil actions for damages or injunctions in federal courts to enforce the federal HIPAA laws and seek attorney’s 
fees and costs associated with pursuing federal civil actions. In addition, state laws govern the privacy and security 

33
of health information in certain circumstances, many of which differ from each other in significant ways and may 
not have the same effect, thus complicating compliance efforts. 
In addition, federal transparency requirements known as the federal Physician Payments Sunshine Act, under the 
Patient Protection and Affordable Care Act, as amended by the Health Care Education Reconciliation Act, or the 
Affordable Care Act, require certain manufacturers of drugs, devices, biologics and medical supplies to report 
annually to the Centers for Medicare & Medicaid Services, within the United States Department of Health and 
Human Services, information related to payments and other transfers of value made by that entity to physicians, 
other healthcare providers and teaching hospitals, as well as ownership and investment interests held by physicians, 
other healthcare providers and their immediate family members. Some state laws require pharmaceutical companies 
to comply with the pharmaceutical industry’s voluntary compliance guidelines and the relevant compliance guidance 
promulgated by the federal government in addition to requiring drug manufacturers to report information related to 
payments and other transfers of value to physicians and other health care providers, and restrict marketing practices 
or require disclosure of marketing expenditures. 
To the extent that any of our products are sold in a foreign country, we may be subject to similar foreign laws and 
regulations, which may include, for instance, applicable post-marketing requirements, including safety surveillance, 
anti-fraud and abuse laws, and implementation of corporate compliance programs and reporting of payments or 
transfers of value to healthcare professionals. 
Coverage and Reimbursement. Government authorities and third-party payors, such as private health insurers and 
health maintenance organizations, decide which medications they will pay for and establish corresponding 
reimbursement levels. In particular, in the United States, private health insurers and other third-party payors often 
provide reimbursement for products and services based on the level at which the government (through the Medicare 
or Medicaid programs) provides reimbursement for such treatments. In the United States, the European Union and 
other potentially significant markets for our product candidates, government authorities and third-party payors are 
increasingly attempting to limit or regulate the price of medical products and services, particularly for new and 
innovative products and therapies, which often has resulted in average selling prices lower than they would 
otherwise be. Further, the increased emphasis on managed healthcare in the United States and on country and 
regional pricing and reimbursement controls in the European Union will put additional pressure on product pricing, 
reimbursement and usage, which may adversely affect our future product sales and results of operations. These 
pressures can arise from rules and practices of managed care groups, judicial decisions and governmental laws and 
regulations related to Medicare, Medicaid and healthcare reform, pharmaceutical reimbursement policies and pricing 
in general. 
Third-party payors are increasingly imposing additional requirements and restrictions on coverage and limiting 
reimbursement levels for medical products. For example, federal and state governments reimburse covered 
prescription drugs at varying rates generally below average wholesale price. These restrictions and limitations 
influence the purchase of healthcare services and products. Legislative proposals to reform healthcare or reduce 
costs under government insurance programs may result in lower reimbursement for our products and product 
candidates or exclusion of our products and product candidates from coverage. The cost containment measures that 
healthcare payors and providers are instituting and any healthcare reform could significantly reduce our revenues 
from the sale of any approved product candidates. We cannot provide any assurances that we will be able to obtain 
and maintain third-party coverage or adequate reimbursement for our product candidates in whole or in part. 
Impact of Healthcare Reform on Coverage, Reimbursement, and Pricing. The Medicare Prescription Drug, 
Improvement, and Modernization Act of 2003, or the MMA, imposed new requirements for the distribution and 
pricing of prescription drugs for Medicare beneficiaries. Under Part D, Medicare beneficiaries may enroll in 
prescription drug plans offered by private entities that provide coverage of outpatient prescription drugs. Part D 
plans include both standalone prescription drug benefit plans and prescription drug coverage as a supplement to 
Medicare Advantage plans. Unlike Medicare Part A and B, Part D coverage is not standardized. Part D prescription 
drug plan sponsors are not required to pay for all covered Part D drugs, and each drug plan can develop its own drug 
formulary that identifies which drugs it will cover and at what tier or level. However, Part D prescription drug 
formularies must include drugs within each therapeutic category and class of covered Part D drugs, though not 
necessarily all the drugs in each category or class. Any formulary used by a Part D prescription drug plan must be 
developed and reviewed by a pharmacy and therapeutic committee. Government payment for some of the costs of 

34
prescription drugs may increase demand for any products for which we receive marketing approval. However, any 
negotiated prices for our future products covered by a Part D prescription drug plan will likely be lower than the 
prices we might otherwise obtain. Moreover, while the MMA applies only to drug benefits for Medicare 
beneficiaries, private payors often follow Medicare coverage policy and payment limitations in setting their own 
payment rates. Any reduction in payment that results from Medicare Part D may result in a similar reduction in 
payments from non-governmental payors. 
The American Recovery and Reinvestment Act of 2009 provides funding for the federal government to compare the 
effectiveness of different treatments for the same illness. A plan for the research will be developed by the 
Department of Health and Human Services, the Agency for Healthcare Research and Quality and the National 
Institutes for Health, and periodic reports on the status of the research and related expenditures will be made to 
Congress. Although the results of the comparative effectiveness studies are not intended to mandate coverage 
policies for public or private payors, it is not clear what effect, if any, the research will have on the sales of any 
product, if any such product or the condition that it is intended to treat is the subject of a study. It is also possible 
that comparative effectiveness research demonstrating benefits in a competitor’s product could adversely affect the 
sales of our product candidates. If third-party payors do not consider our product candidates to be cost-effective 
compared to other available therapies, they may not cover our product candidates, once approved, as a benefit under 
their plans or, if they do, the level of payment may not be sufficient to allow us to sell our products on a profitable 
basis. 
The United States and some foreign jurisdictions are considering enacting or have enacted a number of additional 
legislative and regulatory proposals to change the healthcare system in ways that could affect our ability to sell our 
products profitably. Among policy makers and payors in the United States and elsewhere, there is significant interest 
in promoting changes in healthcare systems with the stated goals of containing healthcare costs, improving quality 
and expanding access. In the United States, the pharmaceutical industry has been a particular focus of these efforts 
and has been significantly affected by major legislative initiatives, including, most recently, PPACA, which became 
law in March 2010 and substantially changed the way healthcare is financed by both governmental and private 
insurers. Among the provisions of the Affordable Care Act of importance to potential product candidates are:

an annual, nondeductible fee on any entity that manufactures or imports specified branded prescription 
drugs and biologic agents, apportioned among these entities according to their market share in certain 
government healthcare programs, although this fee would not apply to sales of certain products 
approved exclusively for orphan indications; 

expansion of eligibility criteria for Medicaid programs by, among other things, allowing states to offer 
Medicaid coverage to certain individuals with income at or below 133% of the federal poverty level, 
thereby potentially increasing a manufacturer’s Medicaid rebate liability; 

expanded manufacturers’ rebate liability under the Medicaid Drug Rebate Program by increasing the 
minimum rebate for both branded and generic drugs and revising the definition of “average 
manufacturer price,” or AMP, for calculating and reporting Medicaid drug rebates on outpatient 
prescription drug prices and extending rebate liability to prescriptions for individuals enrolled in 
Medicare Advantage plans; 

addressed a new methodology by which rebates owed by manufacturers under the Medicaid Drug 
Rebate Program are calculated for drugs that are inhaled, infused, instilled, implanted or injected; 

expanded the types of entities eligible for the 340B drug discount program; 

established the Medicare Part D coverage gap discount program by requiring manufacturers to provide a 
50% point-of-sale-discount off the negotiated price of applicable brand drugs to eligible beneficiaries 
during their coverage gap period as a condition for the manufacturers’ outpatient drugs to be covered 
under Medicare Part D; 

a new Patient-Centered Outcomes Research Institute to oversee, identify priorities in, and conduct 
comparative clinical effectiveness research, along with funding for such research; 

the Independent Payment Advisory Board, or IPAB, which has authority to recommend certain changes 
to the Medicare program to reduce expenditures by the program that could result in reduced payments 

35
for prescription drugs. However, the IPAB implementation has not been clearly defined. PPACA 
provided that under certain circumstances, IPAB recommendations will become law unless Congress 
enacts legislation that will achieve the same or greater Medicare cost savings; and 

established the Center for Medicare and Medicaid Innovation within CMS to test innovative payment 
and service delivery models to lower Medicare and Medicaid spending, potentially including 
prescription drug spending. Funding has been allocated to support the mission of the Center for 
Medicare and Medicaid Innovation from 2011 to 2019. 
Other legislative changes have been proposed and adopted in the United States since the Affordable Care Act was 
enacted. For example, in August 2011, the Budget Control Act of 2011, among other things, created measures for 
spending reductions by Congress. A Joint Select Committee on Deficit Reduction, tasked with recommending a 
targeted deficit reduction of at least $1.2 trillion for the years 2012 through 2021, was unable to reach required 
goals, thereby triggering the legislation’s automatic reduction to several government programs. This includes 
aggregate reductions of Medicare payments to providers of up to 2% per fiscal year, which went into effect in April 
2013 and will remain in effect through 2031, pursuant to the Coronavirus Aid, Relief and Economic Security Act. 
These Medicare sequester reductions have been suspended through the end of March 2022. From April 2022 
through June 2022 a 1% sequester cut will be in effect, with the full 2% cut resuming thereafter. Further, in January 
2013, the American Taxpayer Relief Act of 2012 became law, which, among other things, further reduced Medicare 
payments to several providers, including hospitals, imaging centers and cancer treatment centers, and increased the 
statute of limitations period for the government to recover overpayments to providers from three to five years. 
These healthcare reforms, as well as other healthcare reform measures that may be adopted in the future, may result 
in additional reductions in Medicare and other healthcare funding, more rigorous coverage criteria, new payment 
methodologies and additional downward pressure on the price for any approved product and/or the level of 
reimbursement physicians receive for administering any approved product. Reductions in reimbursement levels may 
negatively impact the prices or the frequency with which products are prescribed or administered. Any reduction in 
reimbursement from Medicare or other government programs may result in a similar reduction in payments from 
private payors. Since enactment of the PPACA, there have been numerous legal challenges and Congressional 
actions to repeal and replace provisions of the law.
Since enactment of the PPACA, there have been, and continue to be, numerous legal challenges and Congressional 
actions to repeal and replace provisions of the law. For example, with enactment of the Tax Cuts and Jobs Act of 
2017, which was signed by President Trump on December 22, 2017, Congress repealed the “individual mandate.” 
The repeal of this provision, which requires most Americans to carry a minimal level of health insurance, became 
effective in 2019. Additionally, the 2020 federal spending package permanently eliminated, effective January 1, 
2020, the PPACA-mandated “Cadillac” tax on high-cost employer-sponsored health coverage and medical device 
tax and, effective January 1, 2021, also eliminates the health insurer tax. Further, the Bipartisan Budget Act of 2018, 
among other things, amended the PPACA, effective January 1, 2019, to increase from 50 percent to 70 percent the 
point-of-sale discount that is owed by pharmaceutical manufacturers who participate in Medicare Part D and to close 
the coverage gap in most Medicare drug plans, commonly referred to as the “donut hole.”
Since enactment of the PPACA, there have been, and continue to be, numerous legal challenges and Congressional 
actions to repeal and replace provisions of the law. For example, with enactment of the Tax Cuts and Jobs Act of 
2017, or the Tax Act, which was signed by President Trump on December 22, 2017, Congress repealed the 
“individual mandate.” The repeal of this provision, which requires most Americans to carry a minimal level of 
health insurance, became effective in 2019. On December 14, 2018, a U.S. District Court judge in the Northern 
District of Texas ruled that the individual mandate portion of the PPACA is an essential and inseverable feature of 
the PPACA, and therefore because the mandate was repealed as part of the Tax Act, the remaining provisions of the 
PPACA are invalid as well. The U.S. Supreme Court heard this case on November 10, 2020 and, on June 17, 2021, 
dismissed this action after finding that the plaintiffs do not have standing to challenge the constitutionality of the 
ACA. Litigation and legislation over the PPACA are likely to continue, with unpredictable and uncertain results.
The Trump Administration also took executive actions to undermine or delay implementation of the PPACA, 
including directing federal agencies with authorities and responsibilities under the PPACA to waive, defer, grant 
exemptions from, or delay the implementation of any provision of the PPACA that would impose a fiscal or 

36
regulatory burden on states, individuals, healthcare providers, health insurers, or manufacturers of pharmaceuticals 
or medical devices. On January 28, 2021, however, President Biden rescinded those orders and issued a new 
executive order that directs federal agencies to reconsider rules and other policies that limit access to healthcare, and 
consider actions that will protect and strengthen that access. Under this order, federal agencies are directed to re-
examine: policies that undermine protections for people with pre-existing conditions, including complications 
related to COVID-19; demonstrations and waivers under Medicaid and the PPACA that may reduce coverage or 
undermine the programs, including work requirements; policies that undermine the Health Insurance Marketplace or 
other markets for health insurance; policies that make it more difficult to enroll in Medicaid and under the PPACA; 
and policies that reduce affordability of coverage or financial assistance, including for dependents.
The costs of prescription pharmaceuticals have also been the subject of considerable discussion in the United States 
To date, there have been several recent U.S. congressional inquiries, as well as proposed and enacted state and 
federal legislation designed to, among other things, bring more transparency to drug pricing, review the relationship 
between pricing and manufacturer patient programs, reduce the costs of drugs under Medicare and reform 
government program reimbursement methodologies for drug products. In 2020, President Trump issued several 
executive orders intended to lower the costs of prescription products and certain provisions in these orders have been 
incorporated into regulations. These regulations include an interim final rule implementing a most favored nation 
model for prices that would tie Medicare Part B payments for certain physician-administered pharmaceuticals to the 
lowest price paid in other economically advanced countries, effective January 1, 2021. That rule, however, has been 
subject to a nationwide preliminary injunction and, on December 29, 2021, CMS issued a final rule to rescind it. 
With issuance of this rule, CMS stated that it will explore all options to incorporate value into payments for 
Medicare Part B pharmaceuticals and improve beneficiaries’ access to evidence-based care.
In addition, in October 2020, the Department of Health and Human Services, or HHS, and the FDA published a final 
rule allowing states and other entities to develop a Section 804 Importation Program, or SIP, to import certain 
prescription drugs from Canada into the United States. The final rule is currently the subject of ongoing litigation, 
but at least six states (Vermont, Colorado, Florida, Maine, New Mexico, and New Hampshire) have passed laws 
allowing for the importation of drugs from Canada with the intent of developing SIPs for review and approval by the 
FDA. Further, on November 20, 2020, HHS finalized a regulation removing safe harbor protection for price 
reductions from pharmaceutical manufacturers to plan sponsors under Part D, either directly or through pharmacy 
benefit managers, unless the price reduction is required by law. The implementation of the rule has been delayed by 
the Biden administration from January 1, 2022 to January 1, 2023 in response to ongoing litigation. The rule also 
creates a new safe harbor for price reductions reflected at the point-of-sale, as well as a new safe harbor for certain 
fixed fee arrangements between pharmacy benefit managers and manufacturers, the implementation of which have 
also been delayed by the Biden administration until January 1, 2023.
On July 9, 2021, President Biden signed Executive Order 14063, which focuses on, among other things, the price of 
pharmaceuticals. The order directs HHS to create a plan within 45 days to combat “excessive pricing of prescription 
pharmaceuticals and enhance domestic pharmaceutical supply chains, to reduce the prices paid by the federal 
government for such pharmaceuticals, and to address the recurrent problem of price gouging.” On September 9, 
2021, HHS released its plan to reduce pharmaceutical prices. The key features of that plan are to: (a) make 
pharmaceutical prices more affordable and equitable for all consumers and throughout the health care system by 
supporting pharmaceutical price negotiations with manufacturers; (b) improve and promote competition throughout 
the prescription pharmaceutical industry by supporting market changes that strengthen supply chains, promote 
biosimilars and generic drugs, and increase transparency; and (c) foster scientific innovation to promote better 
healthcare and improve health by supporting public and private research and making sure that market incentives 
promote discovery of valuable and accessible new treatments. 
At the state level, individual states are increasingly aggressive in passing legislation and implementing regulations 
designed to control pharmaceutical product pricing, including price or patient reimbursement constraints, discounts, 
restrictions on certain product access and marketing cost disclosure and transparency measures, and, in some cases, 
designed to encourage importation from other countries and bulk purchasing. A number of states, for example, 
require drug manufacturers and other entities in the drug supply chain, including health carriers, pharmacy benefit 
managers, wholesale distributors, to disclose information about pricing of pharmaceuticals. In addition, regional 
healthcare organizations and individual hospitals are increasingly using bidding procedures to determine what 
pharmaceutical products and which suppliers will be included in their prescription pharmaceutical and other 

37
healthcare programs. These measures could reduce the ultimate demand for our products, once approved, or put 
pressure on our product pricing. We expect that additional state and federal healthcare reform measures will be 
adopted in the future, any of which could limit the amounts that federal and state governments will pay for 
healthcare products and services, which could result in reduced demand for our product candidates or additional 
pricing pressures.
Exclusivity and Approval of Competing Products 
Patent Term Restoration and Extension. A patent claiming a new drug product may be eligible for a limited patent 
term extension under the Hatch-Waxman Act, which permits a patent restoration of up to five years for patent term 
lost during product development and the FDA regulatory review. The restoration period granted is typically one-half 
the time between the effective date of an IND and the submission date of an NDA, plus the time between the 
submission date of an NDA and the ultimate approval date. Patent term restoration cannot be used to extend the 
remaining term of a patent past a total of 14 years from the product’s approval date. Only one patent applicable to an 
approved drug product is eligible for the extension, and the application for the extension must be submitted prior to 
the expiration of the patent in question. A patent that covers multiple drugs for which approval is sought can only be 
extended in connection with one of the approvals. The United States Patent and Trademark Office, or USPTO, 
reviews and approves the application for any patent term extension or restoration in consultation with the FDA. 
Hatch-Waxman Patent Exclusivity. In seeking approval for a drug through an NDA, applicants are required to list 
with the FDA each patent with claims that cover the applicant’s product or a method of using the product. Upon 
approval of a drug, each of the patents listed in the application for the drug is then published in the FDA’s Approved 
Drug Products with Therapeutic Equivalence Evaluations, commonly known as the Orange Book. Drugs listed in the 
Orange Book can, in turn, be cited by potential competitors in support of approval of an abbreviated new drug 
application, or ANDA, or 505(b)(2) NDA. The FDA’s regulations governing patient listings were largely codified 
into law with enactment of the Orange Book Modernization Act in January 2021. 
Generally, an ANDA provides for marketing of a drug product that has the same active ingredients in the same 
strengths, dosage form and route of administration as the listed drug and has been shown to be bioequivalent through 
in vitro or in vivo testing or otherwise to the listed drug. ANDA applicants are not required to conduct or submit 
results of preclinical or clinical tests to prove the safety or effectiveness of their drug product, other than the 
requirement for bioequivalence testing. Drugs approved in this way are commonly referred to as “generic 
equivalents” to the listed drug, and can often be substituted by pharmacists under prescriptions written for the 
original listed drug. 
A 505(b)(2) application applies to a drug for which the investigations made to show whether or not the drug is safe 
for use and effective in use and relied upon by the applicant for approval of the application “were not conducted by 
or for the applicant and for which the applicant has not obtained a right of reference or use from the person by or for 
whom the investigations were conducted.” As with an ANDA, Section 505(b)(2) authorizes the FDA to approve an 
NDA based on safety and effectiveness data that were not developed by the applicant. 505(b)(2) NDAs generally are 
submitted for changes to a previously approved drug product, such as a new dosage form or indication. 
The ANDA or 505(b)(2) NDA applicant is required to certify to the FDA concerning any patents listed for the 
approved product in the FDA’s Orange Book, except for patents covering methods of use for which the ANDA 
applicant is not seeking approval. Specifically, the applicant must certify with respect to each patent that: 

the required patent information has not been filed; 

the listed patent has expired; 

the listed patent has not expired, but will expire on a particular date and approval is sought after patent 
expiration; or 

the listed patent is invalid, unenforceable, or will not be infringed by the new product. 
Generally, the ANDA or 505(b)(2) NDA cannot be approved until all listed patents have expired, except when the 
ANDA or 505(b)(2) NDA applicant challenges a listed drug. A certification that the proposed product will not 

38
infringe the already approved product’s listed patents or that such patents are invalid or unenforceable is called a 
Paragraph IV certification. If the applicant does not challenge the listed patents or indicate that it is not seeking 
approval of a patented method of use, the ANDA or 505(b)(2) NDA application will not be approved until all the 
listed patents claiming the referenced product have expired. 
If the ANDA or 505(b)(2) NDA applicant has provided a Paragraph IV certification to the FDA, the applicant must 
also send notice of the Paragraph IV certification to the NDA and patent holders once the application has been 
accepted for filing by the FDA. The NDA and patent holders may then initiate patent infringement litigation in 
response to the notice of the Paragraph IV certification. The filing of a patent infringement lawsuit within 45 days 
after the receipt of notice of the Paragraph IV certification automatically prevents the FDA from approving the 
ANDA or 505(b)(2) NDA until the earlier of 30 months, expiration of the patent, settlement of the lawsuit or a 
decision in the infringement case that is favorable to the ANDA applicant. 
Hatch-Waxman Non-Patent Exclusivity. Market and data exclusivity provisions under the FDCA also can delay the 
submission or the approval of ANDAs and 505(b)(2) NDAs for competing products. The FDCA provides a five-year 
period of non-patent data exclusivity within the United States to the first applicant to gain approval of an NDA for a 
new chemical entity. A drug is a new chemical entity if the FDA has not previously approved any other new drug 
containing the same active moiety, which is the molecule or ion responsible for the activity of the drug substance. 
This interpretation was confirmed with enactment of the Ensuring Innovation Act in April 2021. During the 
exclusivity period, the FDA may not accept for review an ANDA or a 505(b)(2) NDA submitted by another 
company that contains the previously approved active moiety. However, an ANDA or 505(b)(2) NDA may be 
submitted after four years if it contains a certification of patent invalidity or non-infringement. 
The FDCA also provides three years of marketing exclusivity for an NDA, 505(b)(2) NDA, or supplement to an 
existing NDA or 505(b)(2) NDA if new clinical investigations, other than bioavailability studies, that were 
conducted or sponsored by the applicant, are deemed by the FDA to be essential to the approval of the application or 
supplement. Three-year exclusivity may be awarded for changes to a previously approved drug product, such as new 
indications, dosages, strengths or dosage forms of an existing drug. This three-year exclusivity covers only the 
conditions of use associated with the new clinical investigations and, as a general matter, does not prohibit the FDA 
from approving ANDAs or 505(b)(2) NDAs for generic versions of the original, unmodified drug product. Five-year 
and three-year exclusivity will not delay the submission or approval of a full NDA; however, an applicant 
submitting a full NDA would be required to conduct or obtain a right of reference to all of the preclinical studies and 
adequate and well-controlled clinical trials necessary to demonstrate safety and effectiveness.
The FDA must establish a priority review track for certain generic drugs, requiring the FDA to review a drug 
application within eight months for a drug that has three or fewer approved drugs listed in the Orange Book and is 
no longer protected by any patent or regulatory exclusivities, or is on the FDA’s drug shortage list. The new 
legislation also authorizes FDA to expedite review of ‘‘competitor generic therapies’’ or drugs with inadequate 
generic competition, including holding meetings with or providing advice to the drug sponsor prior to submission of 
the application. 
Orphan Drug Exclusivity. Under the Orphan Drug Act, a drug that is approved for the orphan drug designated 
indication is granted seven years of orphan drug exclusivity. Orphan drug exclusivity means that the FDA may not 
approve another sponsor’s marketing application for the same drug for the same indication for seven years, except in 
certain limited circumstances. Orphan exclusivity does not block the approval of a different product for the same 
rare disease or condition, nor does it block the approval of the same product for different indications. If a drug or 
biologic designated as an orphan drug ultimately receives marketing approval for an indication broader than what 
was designated in its orphan drug application, it may not be entitled to exclusivity. 
Orphan drug exclusivity will also not bar approval of another product under certain circumstances, including if a 
subsequent product with the same drug or biologic for the same indication is shown to be clinically superior to the 
approved product on the basis of greater efficacy or safety, or providing a major contribution to patient care, or if the 
company with orphan drug exclusivity is not able to meet market demand. This is the case despite an earlier court 
opinion holding that the Orphan Drug Act unambiguously required the FDA to recognize orphan exclusivity 
regardless of a showing of clinical superiority. 

39
In September 2021, the Court of Appeals for the 11th Circuit held that, for the purpose of determining the scope of 
market exclusivity, the term “same disease or condition” in the statute means the designated “rare disease or 
condition” and could not be interpreted by the FDA to mean the “indication or use.” Thus, the court concluded, 
orphan drug exclusivity applies to the entire designated disease or condition rather than the “indication or use.” It is 
unclear how this court decision will be implemented by the FDA.
Pediatric Exclusivity. Pediatric exclusivity is another type of non-patent marketing exclusivity in the United States 
and, if granted, provides for the attachment of an additional six months of marketing protection to the term of any 
existing regulatory exclusivity, including the non-patent and orphan drug exclusivity periods described above, and 
any listed patent. This six-month exclusivity may be granted if an NDA sponsor submits pediatric data that fairly 
respond to a written request from the FDA for such data. The data do not need to show the product to be effective in 
the pediatric population studied; rather, if the clinical trial is deemed to fairly respond to the FDA’s request, the 
additional protection is granted. If reports of requested pediatric studies are submitted to and accepted by the FDA 
within the statutory time limits, whatever statutory or regulatory periods of exclusivity or Orange Book listed patent 
protection cover the drug are extended by six months. This is not a patent term extension, but it effectively extends 
the regulatory period during which the FDA cannot approve an ANDA or 505(b)(2) application owing to regulatory 
exclusivity or listed patents. When any of our products is approved, we anticipate seeking pediatric exclusivity when 
it is appropriate.
European Union Drug Approval Process 
In order to market any product outside of the United States, we would need to comply with numerous and varying 
regulatory requirements of other countries regarding safety and efficacy and governing, among other things, clinical 
trials, marketing authorization, commercial sales and distribution of our products. Whether or not we obtain FDA 
approval for a product, we would need to obtain the necessary approvals by the comparable regulatory authorities of 
foreign countries before we can commence clinical trials or marketing of the product in those countries. The 
approval process varies from country to country and can involve additional product testing and additional 
administrative review periods. The time required to obtain approval in other countries might differ from and be 
longer than that required to obtain FDA approval. Regulatory approval in one country does not ensure regulatory 
approval in another, but a failure or delay in obtaining regulatory approval in one country may negatively impact the 
regulatory process in others. 
Clinical Trial Approval in the EU. On January 31, 2022, the new Clinical Trials Regulation (EU) No 536/2014 
became effective in the European Union and replaced the prior Clinical Trials Directive 2001/20/EC. The new 
regulation aims at simplifying and streamlining the authorization, conduct and transparency of clinical trials in the 
European Union. Under the new coordinated procedure for the approval of clinical trials, the sponsor of a clinical 
trial to be conducted in more than one Member State of the European Union, or EU Member State, will only be 
required to submit a single application for approval. The submission will be made through the Clinical Trials 
Information System, a new clinical trials portal overseen by the European Medicines Agency, or the EMA, and 
available to clinical trial sponsors, competent authorities of the EU Member States and the public.
The new regulation did not change the preexisting requirement that a sponsor must obtain prior approval from the 
competent national authority of the EU Member State in which the clinical trial is to be conducted. If the clinical 
trial is conducted in different EU Member States, the competent authorities in each of these EU Member States must 
provide their approval for the conduct of the clinical trial. Furthermore, the sponsor may only start a clinical trial at a 
specific study site after the applicable ethics committee has issued a favorable opinion. As in the United States, 
information about certain clinical trials must be submitted within specific timeframes to the European Union 
(EudraCT) website: https://eudract.ema.europa.eu/ and other countries.
Marketing Authorization. To obtain marketing approval of a drug under European Union regulatory systems, we 
may submit marketing authorization applications, or MAAs, either under a centralized or decentralized procedure. 
The centralized procedure provides for the grant of a single marketing authorization that is valid for all EU member 
states. The centralized procedure is compulsory for medicines produced by specified biotechnological processes, 
products designated as orphan medicinal products, and products with a new active substance indicated for the 
treatment of specified diseases, and optional for those products that are highly innovative or for which a centralized 
process is in the interest of patients. Under the centralized procedure in the European Union, the maximum 

40
timeframe for the evaluation of an MAA is 210 days, excluding clock stops, when additional written or oral 
information is to be provided by the applicant in response to questions asked by the Scientific Advice Working Party 
of the Committee of Medicinal Products for Human Use, or the CHMP. Accelerated evaluation might be granted by 
the CHMP in exceptional cases, when a medicinal product is expected to be of a major public health interest, 
defined by three cumulative criteria: the seriousness of the disease, such as heavy disabling or life-threatening 
diseases, to be treated; the absence or insufficiency of an appropriate alternative therapeutic approach; and 
anticipation of high therapeutic benefit. In this circumstance, the EMA ensures that the opinion of the CHMP is 
given within 150 days. 
The decentralized procedure provides for approval by one or more other, or concerned, member states of an 
assessment of an application performed by one-member state, known as the reference member state. Under this 
procedure, an applicant submits an application, or dossier, and related materials, including a draft summary of 
product characteristics, and draft labeling and package leaflet, to the reference member state and concerned member 
states. The reference member state prepares a draft assessment and drafts of the related materials within 120 days 
after receipt of a valid application. Within 90 days of receiving the reference member state’s assessment report, each 
concerned member state must decide whether to approve the assessment report and related materials. If a member 
state cannot approve the assessment report and related materials on the grounds of potential serious risk to public 
health, the disputed points may eventually be referred to the European Commission, whose decision is binding on all 
member states. For the EMA, an agreed Pediatric Investigation Plan, which could include a request for waiver or 
deferral, is required prior to submitting an MAA for use for drugs in pediatric populations. 
Priority Medicines, or PRIME, Drug Designation. The EMA may grant PRIME drug designation to medicine 
developers to treat an unmet medical need upon selection. Medicines eligible for PRIME must address an unmet 
medical need, have data available showing the potential to address this need and bring a major therapeutic advantage 
to patients. PRIME designation provides early and enhanced support from the EMA to optimize the development of 
eligible medicines, speeds up their evaluation, and contributes to timely patients’ access. Once a candidate is 
selected for PRIME designation, the EMA will provide scientific advice at key development milestones and confirm 
potential for accelerated assessment at the time of an application for marketing authorization. These medicines are 
considered priority medicines by the EMA.
Data and Market Exclusivity. In the European Union, new chemical entities qualify for eight years of data 
exclusivity upon marketing authorization and an additional two years of market exclusivity. This data exclusivity, if 
granted, prevents regulatory authorities in the European Union from assessing a generic (abbreviated) application for 
eight years, after which generic marketing authorization can be submitted but not approved for two years. The 
overall ten-year period will be extended to a maximum of eleven years if, during the first eight years of those ten 
years, the marketing authorization holder obtains an authorization for one or more new therapeutic indications 
which, during the scientific evaluation prior to their authorization, are held to bring a significant clinical benefit in 
comparison with existing therapies. Even if a compound is considered to be a new chemical entity and the sponsor is 
able to gain the prescribed period of data exclusivity, another company nevertheless could also market another 
version of the drug if such company can complete a full MAA with a complete human clinical trial database and 
obtain marketing approval of its product. 
Orphan Drug Exclusivity. The EMA grants orphan drug designation to promote the development of products that 
may offer therapeutic benefits for life-threatening or chronically debilitating conditions affecting not more than five 
in 10,000 people in the European Union. In addition, orphan drug designation can be granted if the drug is intended 
for a life threatening, seriously debilitating or serious and chronic condition in the European Union and without 
incentives it is unlikely that sales of the drug in the European Union would be sufficient to justify developing the 
drug. Orphan drug designation is only available if there is no other satisfactory method approved in the European 
Union of diagnosing, preventing or treating the condition, or if such a method exists, the proposed orphan drug will 
be of significant benefit to patients. Orphan drug designation provides opportunities for free protocol assistance, fee 
reductions for access to the centralized regulatory procedures before and during the first year after marketing 
authorization and 10 years of market exclusivity of the designated indication following drug approval. Fee 
reductions are not limited to the first year after authorization for small and medium enterprises. The exclusivity 
period may be reduced to six years if the designation criteria are no longer met, including where it is shown that the 
product is sufficiently profitable not to justify maintenance of market exclusivity. 

41
Approval of Companion Diagnostic Devices. In the European Union, medical devices such as companion 
diagnostics must comply with the General Safety and Performance Requirements, or SPRs, detailed in Annex I of 
the EU Medical Devices Regulation (Regulation (EU) 2017/745), or MDR which came into force on May 26, 2021 
and replaced the previously applicable EU Medical Devices Directive (Council Directive 93/42/EEC). Compliance 
with SPRs and additional requirements applicable to companion medical devices is a prerequisite to be able to affix 
the CE Mark of Conformity to medical devices, without which they cannot be marketed or sold. To demonstrate 
compliance with the SPRs, a manufacturer must undergo a conformity assessment procedure, which varies 
according to the type of medical device and its classification. The MDR is meant to establish a uniform, transparent, 
predictable, and sustainable regulatory framework across the EU for medical devices.
Separately, the regulatory authorities in the EU also adopted a new In Vitro Diagnostic Regulation, or IVDR, (EU) 
2017/746, which will become effective in May 2022. The new regulation will replace the In Vitro Diagnostics 
Directive (IVDD) 98/79/EC. Manufacturers wishing to apply to a notified body for a conformity assessment of their 
in vitro diagnostic medical device have until May 2022 to update their Technical Documentation to meet the 
requirements and comply with the new, more stringent Regulation. Once applicable, the regulation will, among 
other things: strengthen the rules on placing devices on the market and reinforce surveillance once they are 
available; establish explicit provisions on manufacturers’ responsibilities for the follow-up of the quality, 
performance, and safety of devices placed on the market; improve the traceability of medical devices throughout the 
supply chain to the end-user or patient through a unique identification number; set up a central database to provide 
patients, healthcare professionals and the public with comprehensive information on products available in the 
European Union; and strengthen rules for the assessment of certain high-risk devices, such as implants, which may 
have to undergo an additional check by experts before they are placed on the market.
Reimbursement and Pricing of Prescription Pharmaceuticals. In the EU, similar political, economic and 
regulatory developments to those in the United States may affect our ability to profitably commercialize our product 
candidates, if approved. In markets outside of the U.S. and the EU, reimbursement and healthcare payment systems 
vary significantly by country and many countries have instituted price ceilings on specific products and therapies. In 
many countries, including those of the EU, the pricing of prescription pharmaceuticals is subject to governmental 
control and access. In these countries, pricing negotiations with governmental authorities can take considerable time 
after the receipt of marketing approval for a product. To obtain reimbursement or pricing approval in some 
countries, pharmaceutical firms may be required to conduct a clinical trial that compares the cost-effectiveness of 
the product to other available therapies. 
General Data Protection Regulation. The collection, use, disclosure, transfer, or other processing of personal data 
regarding individuals in the EU, including personal health data, is subject to the EU General Data Protection 
Regulation, or GDPR, which became effective on May 25, 2018. The GDPR is wide-ranging in scope and imposes 
numerous requirements on companies that process personal data, including requirements relating to processing 
health and other sensitive data, obtaining consent of the individuals to whom the personal data relates, providing 
information to individuals regarding data processing activities, implementing safeguards to protect the security and 
confidentiality of personal data, providing notification of data breaches, and taking certain measures when engaging 
third-party processors. 
The GDPR also imposes strict rules on the transfer of personal data to countries outside the EU, including the 
United States and permits data protection authorities to impose large penalties for violations of the GDPR, including 
potential fines of up to €20 million or 4% of annual global revenues, whichever is greater. The GDPR also confers a 
private right of action on data subjects and consumer associations to lodge complaints with supervisory authorities, 
seek judicial remedies, and obtain compensation for damages resulting from violations of the GDPR. Compliance 
with the GDPR will be a rigorous and time-intensive process that may increase the cost of doing business or require 
companies to change their business practices to ensure full compliance.
Compliance with the GDPR is a rigorous and time-intensive process that may increase the cost of doing business or 
require companies to change their business practices to ensure full compliance. In July 2020, the Court of Justice of 
the European Union, or the CJEU, invalidated the EU-U.S. Privacy Shield framework, one of the mechanisms used 
to legitimize the transfer of personal data from the EEA to the United States. The CJEU decision also drew into 
question the long-term viability of an alternative means of data transfer, the standard contractual clauses, for 
transfers of personal data from the EEA to the United States. 

42
Brexit and the Regulatory Framework in the United Kingdom. 
The United Kingdom’s withdrawal from the EU took place on January 31, 2020. The EU and the U.K. reached an 
agreement on their new partnership in the Trade and Cooperation Agreement, or the Brexit Agreement, which was 
applied provisionally beginning on January 1, 2021 and which entered into force on May 1, 2021. The Brexit 
Agreement focuses primarily on free trade by ensuring no tariffs or quotas on trade in goods, including healthcare 
products such as medicinal products. Thereafter, the EU and the U.K. will form two separate markets governed by 
two distinct regulatory and legal regimes. As such, the Brexit Agreement seeks to minimize barriers to trade in 
goods while accepting that border checks will become inevitable as a consequence that the U.K. is no longer part of 
the single market. As of January 1, 2021, the Medicines and Healthcare products Regulatory Agency, or the MHRA, 
became responsible for supervising medicines and medical devices in Great Britain, comprising England, Scotland 
and Wales under domestic law whereas Northern Ireland continues to be subject to EU rules under the Northern 
Ireland Protocol. The MHRA will rely on the Human Medicines Regulations 2012 (SI 2012/1916) (as amended), or 
the HMR, as the basis for regulating medicines. The HMR has incorporated into the domestic law the body of EU 
law instruments governing medicinal products that pre-existed prior to the U.K.’s withdrawal from the EU.
Furthermore, while the Data Protection Act of 2018 in the United Kingdom that “implements” and complements the 
European Union’s General Data Protection Regulation, or GDPR, has achieved Royal Assent on May 23, 2018 and 
is now effective in the United Kingdom, it is still unclear whether transfer of data from the European Economic 
Area, or EEA, to the United Kingdom will remain lawful under GDPR. The Brexit Agreement provides for a 
transitional period during which the United Kingdom will be treated like an European Union member state in 
relation to processing and transfers of personal data for four months from January 1, 2021. This may be extended by 
two further months. After such period, the United Kingdom will be a “third country” under the GDPR unless the 
European Commission adopts an adequacy decision in respect of transfers of personal data to the United Kingdom. 
The United Kingdom has already determined that it considers all of the EU 27 and EEA member states to be 
adequate for the purposes of data protection, ensuring that data flows from the United Kingdom to the EU/EEA 
remain unaffected.
Employees and Human Capital Resources 
As of March 1, 2022, we had approximately 250 full-time and part-time employees. After taking into account the 
cross-functional headcount reduction announced on March 1, 2022, we expect that we will have approximately 215 
full-time and part-time employees, approximately 95 of whom will be primarily engaged in research and 
development activities. To provide us with flexibility in meeting varying workflow demands, we also engage 
temporary workers and consultants when needed.
Our human capital is integral in helping us achieve our mission to rewrite treatment for cancer through novel 
epigenetic medicines. We believe that we have built a culture of community, along with our EpiExcellence cultural 
attributes, and many of these qualities are foundational. Our EpiExcellence cultural attributes include: 

Camaraderie: connectedness, humor, liking each other, fun, in it together, mutual respect

Collaboration: integrated decision-making, teamwork, internal/external partnerships, interdependent, 
“right people, right time, right involvement”

Discipline: execution, prioritization, focus, accountability, consistency, quality

Innovation: risk-tolerant, creativity, evidence-based, curiosity, continuous learning

Openness: honesty, constructive dissent, transparency, courageous conversations, assumption of good 
intent, trust

Patient-focus: shared purpose, inspired, passionate, motivated, sense of urgency

Resilience: nimble, optimistic, embracing change, evolutionary, adaptable 
We have been intentional in ensuring that we are creating a culture and company that offers a vibrant community to 
our employees where we can fully be ourselves at work. We strive to ensure that Epizyme is a place where all 

43
people experience equality, where we value diversity in all its forms, and that we are modeling these behaviors in 
the world outside Epizyme as corporate citizens. 
Information about our Executive Officers 
The following table sets forth the name, age and position of each of our executive officers as of February 25, 2022.
Name
Age
Position
Grant Bogle
64
President, Chief Executive Officer and Director
Shefali Agarwal
48
Executive Vice President, Chief Medical and Development 
Officer
Jeffery L. Kutok
55
Chief Scientific Officer
Grant Bogle has served as a director since September 2019 and our President and Chief Executive Officer since 
August 2021. Mr. Bogle served as Senior Vice President and Chief Commercial Officer for Tesaro, Inc, a 
biopharmaceutical company, or Tesaro, from July 2015 to June 2019. Prior to joining Tesaro, Mr. Bogle served as 
Senior Vice President, Pharmaceutical and Biotech Solutions at McKesson Specialty Health (formerly U.S. 
Oncology) from July 2007 to June 2015. Previously, he was Senior Vice President of Sales and Marketing for 
Millennium Pharmaceuticals. Mr. Bogle holds a B.A. in economics from Dartmouth College, an M.B.A. from 
Columbia University and is a Senior Fellow of the Advanced Leadership Initiative at Harvard University.
Dr. Shefali Agarwal has served as our Executive Vice President, Chief Medical and Development Officer since 
February 2021 and served as our Chief Medical Officer from June 2018 to February 2021. Prior to joining us, Dr. 
Agarwal held leadership positions across medical research, clinical development, clinical operations and medical 
affairs. She most recently served as chief medical officer at SQZ Biotech, a biotechnology company developing cell 
therapies for patients with a wide range of diseases, from July 2017 to May 2018 and as a non-executive advisor 
from May 2018 to July 2018, where she built and led the clinical development organization, which included clinical 
research operations and the regulatory function. Before SQZ Biotech, Dr. Agarwal also held leadership positions at 
Curis, Inc. a biotechnology company developing therapeutics for the treatment of cancer, from July 2016 to July 
2017 and Tesaro from July 2013 to July 2017. Dr. Agarwal also held positions of increasing responsibility at AVEO 
Pharmaceuticals, Inc., a biopharmaceutical company, from December 2011 to July 2013, Covidien, a medical 
devices and health care products company, from April 2010 to December 2011, and Pfizer Inc., a pharmaceutical 
company with a wide range of treatments, from June 2005 to April 2010. She has served as a member of the board 
of directors of Gritstone bio, Inc., a publicly traded clinical-stage biotechnology company, since June 2021; Fate 
Therapeutics, Inc., a publicly traded clinical-stage biopharmaceutical company, since July 2019; and Onxeo SA, a 
publicly traded clinical-stage biopharmaceutical company, since April 2021. Dr. Agarwal received her MBBS 
medical degree from Karnataka University’s Mahadevappa Rampure Medical School in India, Master’s Degree in 
Public Health from Johns Hopkins University, where she led clinical research in the Department of Anesthesiology 
and Critical Care Medicine, and a Master of Science degree in Business from the University of Baltimore’s Merrick 
School of Business.
Jeffery L. Kutok, M.D., Ph.D., has served as our Chief Scientific Officer since joining us in April 2020. Dr. Kutok 
previously served as Chief Scientific Officer of Infinity Pharmaceuticals, Inc., or Infinity, a biotechnology company 
that develops cancer medication, from February 2017 to March 2020. Dr. Kutok previously served as Infinity’s Vice 
President of Biology and Translational Science from August 2013 to February 2017, and in other roles with 
increasing responsibility from January 2011 to August 2013. Prior to joining Infinity, Dr. Kutok was an associate 
professor of pathology at Harvard Medical School and Brigham and Women’s Hospital. Dr. Kutok’s laboratory 
focused on translational medicine research and biomarker identification in cancer, and he is an author on over 200 
journal articles, reviews and book chapters. Dr. Kutok is board certified in Anatomic Pathology and Hematology and 
had clinical duties in Hematopathology and Molecular Diagnostics at Brigham and Women’s Hospital. Dr. Kutok 
received his B.S. in biology and his M.D., Ph.D. in medicine and molecular pathology from the State University of 
New York at Stony Brook. He was also a post-doctoral fellow at Harvard University in the laboratory of Dr. Gary 
Gilliland, M.D., Ph.D.

44
Our Corporate Information 
We were incorporated under the laws of the state of Delaware on November 1, 2007 under the name Epizyme, Inc. 
Our principal executive offices are located at 400 Technology Square, 4th Floor, Cambridge, Massachusetts 02139. 
Our telephone number is (617) 229-5872, and our website is located at www.epizyme.com. References to our 
website are inactive textual references only and the content of our website should not be deemed incorporated by 
reference into this Annual Report on Form 10-K.
Available Information 
Our Annual Reports on Form 10-K, Quarterly Reports on Form 10-Q, Current Reports on Form 8-K and any 
amendments to these reports filed or furnished pursuant to Section 13(a) or 15(d) of the Securities Exchange Act of 
1934, are available free of charge on our website located at www.epizyme.com as soon as reasonably practicable 
after they are electronically filed with or furnished to the SEC. These reports are also available at the SEC’s Internet 
website at www.sec.gov. 
A copy of our Corporate Governance Guidelines, Code of Business Conduct and Ethics and the charters of the Audit 
Committee, Organizational Health and Compensation Committee, and Nominating and Corporate Governance 
Committee are posted on our website, www.epizyme.com, under “Investors & Media” and are available in print to 
any person who requests copies by contacting Epizyme by calling (617) 229-5872 or by writing to Epizyme, Inc., 
400 Technology Square, 4th Floor, Cambridge, Massachusetts 02139.

45
Item 1A. Risk Factors 
Risk Factors
Careful consideration should be given to the following risk factors, in addition to the other information set forth in 
this Annual Report on Form 10-K and in other documents that we file with the SEC, in evaluating our company and 
our business. Investing in our common stock involves a high degree of risk. If any of the following risks and 
uncertainties actually occurs, our business, prospects, financial condition and results of operations could be 
materially and adversely affected. The risks described below are not intended to be exhaustive and are not the only 
risks facing our company. New risk factors can emerge from time to time, and it is not possible to predict the impact 
that any factor or combination of factors may have on our business, prospects, financial condition and results of 
operations. 
In addition, the COVID-19 pandemic has impacted, continues to impact and in the future may exacerbate or further 
impact risks discussed in this Annual Report on Form 10-K, any of which could have a material effect on us. This 
situation is changing rapidly and additional impacts may arise.
Risks Related to Product Development and Commercialization 
We are dependent on the successful development and commercialization of tazemetostat. If we do not successfully 
commercialize TAZVERIK for the indications for which TAZVERIK is approved or are unable to develop, obtain 
marketing approval of, and commercialize tazemetostat for additional indications, either alone or through a 
collaboration, or if we experience significant delays in doing so, our business could be harmed. 
Our EZH2 inhibitor, TAZVERIK, is approved in the United States for the treatment of epithelioid sarcoma, or ES, 
and for follicular lymphoma, or FL. We have no other products approved for sale. We are investing a significant 
portion of our efforts and financial resources to fund the development and commercialization of tazemetostat.  
Commercial sales of TAZVERIK for the treatment of ES commenced in the first quarter of 2020 and commercial 
sales of TAZVERIK for the treatment of FL commenced near the end of the second quarter of 2020. 
In connection with the accelerated approval of our ES new drug application, or NDA and our FL supplemental 
NDA, or sNDA, continued approval is contingent upon verification and description of clinical benefit in a 
confirmatory program in each indication. We are conducting Phase 1b/3 trials to assess TAZVERIK in combination 
with doxorubicin compared with doxorubicin plus placebo as a front-line treatment for ES and to evaluate the 
combination of TAZVERIK with “R2” (Revlimid plus rituximab), an approved chemotherapy-free treatment 
regimen, for FL patients in the second-line or later treatment setting. These trials are expensive and time-consuming 
and may not confirm such benefit and subject the NDAs to withdrawal. If a confirmatory program does not verify 
clinical benefit for an indication, we may have to withdraw our accelerated approval for that indication. If any of 
these outcomes occurs, either to TAZVERIK or to any future product candidate for which we may seek marketing 
approval, we may be forced to abandon our development efforts for tazemetostat or such future product candidates, 
which could significantly harm our business.
We and our collaborators are conducting clinical trials of tazemetostat in other indications and in combination with 
other products. Our EZM0414 product candidate is in early clinical development and all of our product candidates 
are still in preclinical development. As a result, our prospects are substantially dependent on our ability, or the 
ability of any future collaborator, to successfully commercialize tazemetostat for ES and FL in the approved 
indications and to develop, obtain marketing approval for and successfully commercialize tazemetostat in one or 
more additional disease indications. 

46
The success of tazemetostat will depend on several factors, including the following: 

success of the ongoing commercialization of TAZVERIK for ES and FL in the approved indications, 
whether alone or in combination with other products;

successful confirmatory trials of TAZVERIK in the approved indications that are satisfactory to the 
FDA and maintenance of the continued acceptable safety profiles of the products following approval;

continued implementation and maintenance of effective sales, marketing and distribution capabilities 
and strategies for commercialization of TAZVERIK;

acceptance of TAZVERIK for ES, FL, and any other indication for which it may be approved by 
physicians, patients, third-party payors and others in the medical community;

timely submission of a marketing authorization application to and timely receipt of marketing approval 
from the European Medicines Agency, or EMA, for ES, FL or any future indications; 

the extent of any required post-marketing approval commitments to applicable regulatory authorities;

successful enrollment in and completion of clinical trials for the treatment of additional indications; 

safety, tolerability and efficacy profiles that are satisfactory to the FDA, the EMA, or any comparable 
foreign regulatory authority for marketing approval for additional indications and maintenance of 
continued acceptable safety profile following approval;

effectively competing with other therapies;

obtaining and maintaining healthcare insurance coverage and adequate reimbursement; 

making arrangements with third-party manufacturers for, or establishing, clinical and commercial 
manufacturing capabilities; 

obtaining and maintaining patent and trade secret protection and regulatory exclusivity for our products 
and product candidates; 

protecting our rights in our intellectual property portfolio; and 

effectively and successfully navigating the commercial and operational challenges and impacts resulting 
from the COVID-19 pandemic. 
Many of these factors are beyond our control, including clinical development, the regulatory review process, 
potential threats to our intellectual property rights and the manufacturing, marketing and sales efforts of any 
collaborator. If any of these factors adversely affects the development or commercialization of tazemetostat, we may 
not be able to successfully develop or commercialize tazemetostat on a timely basis or at all, which would materially 
harm our business. 
The COVID-19 pandemic has impacted and may continue to impact our commercial launch efforts for 
TAZVERIK in FL and ES and has led to some delays in clinical trial startup, and may affect our ability to initiate 
and complete preclinical studies and our ongoing and planned clinical trials, disrupt regulatory activities, further 
disrupt commercialization of TAZVERIK, or have other adverse effects on our business and operations. In 
addition, the COVID-19 pandemic has caused substantial disruption in the global financial markets, global 
supply chains and may adversely impact economies worldwide, which could result in adverse effects on our 
business and operations.
The COVID-19 pandemic, which began in late 2019 and has spread worldwide, is causing many governments to 
implement measures intended to slow the spread of the outbreak through quarantines, travel restrictions, heightened 
border scrutiny, and other measures. The outbreak and government measures taken in response have also had a 
significant impact, both direct and indirect, on businesses and commerce, as worker shortages have occurred; supply 
chains have been disrupted; facilities have been disrupted and production has been suspended; and demand for 
certain goods and services, such as medical services and supplies, has spiked, while demand for other goods and 
services, such as travel, has fallen. The future progression of the outbreak and its effects on our business and 
operations are uncertain.

47
We and our contract manufacturing organizations, or CMOs, and contract research organizations, or CROs, may 
face disruptions that may affect our ability to initiate and conduct preclinical studies and our planned and ongoing 
clinical trials, including disruptions in procuring items that are essential for our research and development activities, 
such as access to raw materials used in the manufacture of tazemetostat, EZM0414 and/or our future product 
candidates, laboratory supplies used in our preclinical studies and ongoing clinical trials, or animals that are used for 
preclinical testing for which there are shortages because of ongoing efforts to address the outbreak, and resulting 
disruptions to many global supply chains. We and our CROs and CMOs, as well as clinical trial sites, may face 
disruptions related to the conduct of our ongoing clinical trials, planned clinical trials or future clinical trials arising 
from manufacturing disruptions, staffing disruptions and limitations in regard to our internal activities and the 
activities of our CROs and CMOs, and delays in the ability to obtain necessary institutional review board or other 
necessary site approvals or delays in site initiations or site monitoring visits, as well as other delays at clinical trial 
sites. We may also face limitations on enrollment and patients withdrawing from our clinical trials or not complying 
with the protocol procedures, which could delay completion of our clinical trials or adversely affect the data 
generated by our clinical trials. For example, we have experienced some delays in clinical trial startup activities due 
to what we believe to be mostly related to COVID-19 related capacity constraints and resulting delays in the 
packaging and labeling of clinical drug supply at a third-party manufacturer. The response to the COVID-19 
pandemic may redirect resources with respect to regulatory and intellectual property matters in a way that could 
adversely impact our ability to progress regulatory approvals and protect our intellectual property. In addition, we 
may face impediments to regulatory meetings and approvals due to measures intended to limit in-person 
interactions. 
We commenced commercial sales of TAZVERIK in January 2020, and the pandemic and related government 
imposed measures have limited our ability to readily access accounts and healthcare professionals, in person or at 
all, to provide medical information in support of TAZVERIK utilization. For example, the COVID-19 pandemic has 
negatively impacted ES and FL patient visits to physicians, new patient starts across all lines of treatment as well as 
the ability of our field-based teams to fully access ES and FL prescribers. While our field-based teams continue to 
use virtual formats as well as in-person interactions, where possible, to allow us to serve the needs of healthcare 
providers, patients and other stakeholders, access to prescribers remains restrictive, and we expect these challenges 
to continue through the first half of 2022. Additionally, we expect that some of these challenges posed by some of 
the changes brought about by the COVID-19 pandemic, such as ongoing restrictions to access prescribers by 
traditional sales personnel, will likely persist even after the resolution of the pandemic. The pandemic has 
significantly impacted economies worldwide, which could result in adverse effects on our business and operations. 
Moreover, the pandemic has caused substantial disruption in the global financial markets and supply chains and may 
continue to adversely impact economies worldwide, which could result in adverse effects on our business and 
operations as well as the volatility of our stock price and trading in our stock. 
We are implementing a multi-stage return to office plan based on guidance from federal, state and local government 
authorities, and in October 2021 we opened our facilities to all employees who expressed interest in participating in 
a return-to-office pilot program. In the meantime, many of our employees continue to work in a remote operating 
model. Our laboratory scientists who engage in bench research activities now have full access to our laboratories. 
We are using our pilot program to further evaluate this hybrid model and will use that evaluation to formulate how 
we will move forward. We expect that some form of a hybrid model will continue to exist for us in the future. 
Changes in guidance from federal, state and local government authorities could impact our return to office plan, and 
require us to increasingly rely on personnel working remotely. For example, changes to guidance from federal, state 
and local government authorities to restrict or limit in-person interactions could result in our laboratory staff that is 
presently engaged in research and development activities to have restricted access to laboratories. Such restricted 
access could delay timely completion of preclinical activities and the initiation of additional clinical trials for other 
of our development programs.
A remote or hybrid operating model may negatively impact productivity, or disrupt, delay, or otherwise adversely 
impact our business. In addition, this could increase our cyber security risk, create data accessibility concerns, and 
make us more susceptible to communication disruptions, any of which could adversely impact our business 

48
operations or delay necessary interactions with state, local and federal regulators, ethics committees, manufacturing 
sites, research or clinical trial sites and other important agencies and contractors, including our CROs and CMOs.
Due to the evolving and uncertain global impacts of the COVID-19 pandemic, we cannot precisely determine or 
quantify the impact that the COVID-19 pandemic has had or will have on our business, financial condition, results 
of operations, and prospects for the fiscal year ending December 31, 2022 and beyond. 
Tazemetostat, EZM0414 or any other product candidate that we develop may fail to achieve the degree of market 
acceptance by physicians, patients, third-party payors and others in the medical community necessary for 
commercial success. 
Tazemetostat, EZM0414 or any other product candidates that we develop may fail to gain sufficient market 
acceptance by physicians, patients, third-party payors and others in the medical community. If tazemetostat, 
EZM0414 or any other such product candidate that we develop does not achieve an adequate level of acceptance, we 
may not generate significant product revenues and we may not become profitable. The degree of market acceptance 
of tazemetostat, EZM0414 or any other product candidates that we develop will depend on a number of factors, 
including: 

the efficacy and potential advantages compared to alternative treatments; 

our ability to offer our products for sale at competitive prices; 

the convenience and ease of administration compared to alternative treatments; 

the willingness of the patient population to try new therapies and of physicians to prescribe these 
therapies; 

the strength of marketing and distribution support; 

the availability of third-party coverage and adequate reimbursement; 

the prevalence and severity of any side effects; 

any safety events that may have occurred in connection with the development of the product candidate; 
and 

any restrictions on the use of our products together with other medications. 
In addition, the potential market opportunity for tazemetostat is difficult to precisely estimate. Our estimates of the 
potential market opportunity for tazemetostat include several key assumptions based on our industry knowledge, 
industry publications, third-party research reports and other surveys. While we believe that our internal assumptions 
are reasonable, no independent source has verified such assumptions. If any of these assumptions proves to be 
inaccurate, then the actual market for tazemetostat could be smaller than our estimates of our potential market 
opportunity. If the actual market for tazemetostat, EZM0414 or any other product candidate is smaller than we 
expect, our product revenue may be limited and it may be more difficult for us to achieve or maintain profitability.
If we are unable to maintain effective sales, marketing and distribution capabilities, we may not be successful in 
commercializing tazemetostat or any other product candidates that we may develop if and when such product 
candidate is approved. 
To achieve commercial success for any product for which we obtain marketing approval, we will need to maintain 
an effective sales and marketing organization. 
We have established, and plan to continue to build and refine, the infrastructure that we believe is necessary and 
appropriate to support the ongoing commercialization and marketing of TAZVERIK for the approved indications in 
the United States and the successful commercial launch and marketing of tazemetostat for other indications and in 
other jurisdictions and of other product candidates and future product candidates that may receive marketing 
approval. There are risks involved with maintaining our own sales, marketing and distribution capabilities. For 
example, recruiting, training and retaining a sales force is expensive and time consuming and any failure to do so 
successfully could negatively affect sales or any commercial launch of a product. If the commercial launch of a 
product candidate for which we recruit a sales force and establish marketing capabilities is delayed or does not occur 

49
for any reason, we would have prematurely or unnecessarily incurred these commercialization expenses. These 
efforts may be costly, and our investment would be lost if we cannot retain or reposition our sales and marketing 
personnel. 
Factors that may inhibit our efforts to successfully commercialize our products on our own include: 

our inability to recruit, train and retain adequate numbers of effective sales and marketing personnel; 

the inability of sales personnel to obtain access to physicians or persuade adequate numbers of 
physicians to prescribe any current or future products; 

the lack of complementary products to be offered by sales personnel, which may put us at a competitive 
disadvantage relative to companies with more extensive product lines; and 

unforeseen costs and expenses associated with creating an independent sales and marketing 
organization. 
If we are unable to effectively maintain our own sales, marketing and distribution capabilities and as a result we 
determine to enter into arrangements with third parties to perform these services, our product revenues and our 
profitability, if any, could be lower than if we were to market, sell and distribute any products that we develop 
ourselves. In addition, we may determine to seek to enter into arrangements with third parties to perform these 
services in certain geographies outside the United States or for additional indications. However, we may not be 
successful in entering into arrangements with third parties to sell, market and distribute TAZVERIK or any current 
or future product candidates or may be unable to do so on terms that are acceptable to us. We likely will have little 
control over such third parties, and any of them may fail to devote the necessary resources and attention to sell, 
market or distribute our products effectively. If we do not establish and maximize sales, marketing and distribution 
capabilities successfully, either on our own or in collaboration with third parties, we will not be successful in 
commercializing TAZVERIK or any current or future product candidates. 
Our changes to our commercial strategy and organization, adjustments to our operating plans, including 
operating expense reductions, prioritization of development activities and leadership transitions may not be 
successful, may not result in accelerated commercial adoption of TAZVERIK and greater product revenues or 
anticipated savings, could result in total costs and expenses that are greater than expected, could result in us 
forgoing business opportunities and could disrupt our business.
In August 2021, we announced changes to our leadership team with the resignation of our President and Chief 
Executive Officer, Robert Bazemore, and the appointment of Grant Bogle, a member of our board of directors since 
September 2019, as President and Chief Executive Officer, each effective as of August 9, 2021. In addition, in 
August 2021, we made the decision to eliminate the Chief Commercial Officer position, effective at the end of 
October 2021, and in October 2021 we announced the elimination of the role and departure of our now-former 
Executive Vice President, Chief Strategy and Business Officer. 
In addition, in August 2021, we announced changes to our commercial strategy and organization in an effort to 
accelerate commercial adoption of TAZVERIK as well as a broader operational cost reduction plan. As part of our 
cost reduction plan, we implemented a cross-functional reduction of approximately 11% of our then-current 
workforce.
In March 2022, we announced the implementation of a further reduction of operating expenses, including additional 
workforce reductions and changes to our broader organization, as well as the re-prioritization of our pipeline and 
investment of company resources. We further reduced our workforce by approximately 12% of our then-current 
employees under these March 2022 expense reductions. We plan to continue to implement our broader operational 
expense reduction effort, and to monitor and seek opportunities to further reduce our operating expenses.
We may not realize, in full or in part, the anticipated benefits, savings and improvements from these changes or 
from any future changes we may decide to make. For instance, the changes to our commercial strategy and 
organization may not result in accelerated commercial adoption of TAZVERIK or greater product revenues. We 
believe that the commercial launch has been adversely affected by the COVID-19 pandemic and may continue to be 

50
adversely affected by the pandemic. In addition, market acceptance of TAZVERIK and product revenues have been 
adversely impacted by other factors, including competitive therapies and the use of our patient assistance program, 
which our changes may not address. The reduction in the size of our field organization and the prior departure of our 
Chief Commercial Officer may also limit the success of our refined strategy. 
Our organizational changes, operating plan adjustments and operating expense reductions also may not be 
successful. If we are unable to realize the expected operational efficiencies and cost savings from these changes, our 
operating results and financial condition would be adversely affected. We also cannot ensure that we will not have to 
undertake additional workforce reductions or other cost-cutting measures in the future. Furthermore, these changes 
as well as the leadership transitions, pipeline reprioritization, and any future additional workforce reductions or other 
cost-cutting measures may be disruptive to our operations. For example, our workforce reductions, leadership 
changes and pipeline reprioritization could yield unanticipated consequences, such as attrition beyond planned staff 
reductions and negative impact on employee morale or could make it more difficult to fulfill our day-to-day 
operations. Our workforce reductions, leadership changes and pipeline reprioritization could also harm our ability to 
attract and retain qualified management, scientific, clinical, manufacturing and sales and marketing personnel who 
are critical to our business. In 2021, our annualized turnover rate was higher than in prior years and these changes 
could further or exacerbate that trend. Any failure to attract or retain qualified personnel could prevent us from 
successfully commercializing TAZVERIK, developing tazemetostat and discovering and developing EZM0414 and 
any future product candidates.
We face substantial competition, which may result in others discovering, developing or commercializing products 
before or more successfully than we do. 
The development and commercialization of new drug products is highly competitive. We face competition with 
respect to tazemetostat, and will likely face competition with respect to our EZM0414 product candidate or any 
other product candidates that we may seek to develop or commercialize in the future, from major pharmaceutical 
companies, specialty pharmaceutical companies and biotechnology companies worldwide. There are a number of 
large pharmaceutical and biotechnology companies that currently market and sell products or are pursuing the 
development of products for the treatment of many of the indications for which we are selling TAZVERIK and for 
which we are developing tazemetostat. Some of these competitive products and therapies are based on scientific 
approaches that are the same as or similar to our approach, and others are based on entirely different approaches. 
Potential competitors also include academic institutions, government agencies and other public and private research 
organizations that conduct research, seek patent protection and establish collaborative arrangements for research, 
development, manufacturing and commercialization of pharmaceutical products that may compete with our products 
or product candidates. Tazemetostat, EZM0414 and any future product candidates that we successfully develop and 
commercialize will compete with existing therapies and new therapies that may become available in the future.
In the relapsed and refractory FL patient setting, both current and near-term competition for tazemetostat exists. The 
most common current treatments for FL are chemotherapies, usually combined with the CD-20 antibodies Rituxan 
or Gazyva. Multiple PI3K therapies, such as copanlisib (ALIQOPA) and umbralisib (UKONIQ) are approved for 
patients with relapsed/refractory FL. These therapies are utilized predominantly in the third line or later treatment. 
Recently, two companies have announced that there have been voluntary withdrawals of accelerated approvals for 
FL indications for two PI3K inhibitors, idelalisib (ZYDELIG) and duvelisib (COPIKTRA) in the U.S. market. 
Additionally, parsaclisib’s NDA has been voluntarily withdrawn for the treatment of patients with 
relapsed/refractory FL. The CAR-T therapy YESCARTA is also approved for the treatment of patients with 
relapsed/refractory FL. While CD20, PI3K and CAR-T therapies are approved in FL, there are no therapies that are 
approved specifically for the treatment of tumors associated with EZH2 activating mutations. There are a number of 
companies currently evaluating investigational agents in the relapsed and refractory follicular lymphoma patient 
setting including the development of additional PI3K inhibitors, CAR-T therapies and bispecific monoclonal 
antibodies. Zandelisib is in development by MEI Pharma for FL patients that are refractory to treatment or relapsed 
after two prior lines of therapy. Novartis is also developing its CAR-T therapy, KYMRIAH, for the treatment of 
relapsed or refractory FL patients and is undergoing priority review by the FDA. The EMA also accepted Novartis’ 
Type II Variation for KYMRIAH in adult patients with relapsed or refractory FL after two prior lines of treatment in 
the third quarter of 2021. The bispecific antibody furthest along in development in relapsed or refractory FL is 
Roche’s CD3/CD20 bispecific mosunetuzumab.
In the ES patient setting, there are no therapies approved specifically for epithelioid sarcoma, other than 
TAZVERIK. Most of the approved therapies utilized in ES are more broadly approved for soft tissue sarcoma in 

51
general. Furthermore, the only therapies in late stage clinical trials are being developed for the treatment of soft 
tissue sarcoma as well. 
In the multiple myeloma patient setting, the most common treatments, which compete with EZM0414, include IMiD 
(include Revlimid (lenalidomide), Pomalyst (pomalidomide), and Thalidomide (thalomid)), proteasome inhibitors 
(including Velcade (bortezomib), Kyprolis (xarfilzomib), and Ninlaro (ixazomib)), and anti-CD38 mAb (including 
Darzalex (daratumumab) and Sarclisa (isatuximab-irfc)) combinations. Current therapies for the relapsed or 
refractory population also include BCMA targeting CAR-Ts and ADCs. The multiple myeloma pipeline is robust, 
and includes BCMA CAR-T therapies, bispecific antibodies, BiTEs, and CELMoDs. Additionally, there are assets 
in development for high risk MM and the t(4;14) subpopulation, including K36’s MMSET inhibitor KTX-1001.
For DLBCL, the most common treatments are chemotherapies, often in combination with the monoclonal antibody 
Rituxan (rituximab) as well as autologous stem cell transplants. In the relapsed or refractory patient setting, current 
therapies include CAR-T therapies (Kymriah (tisagenlecleucel), Yescarta (axicabtagene ciloleucel), Breyanzi 
(lisocabtagene maraleucel)), a CD19 mAb (Monjuvi (tafasitamab)), and ADCs (Policy (polatuzumab vedotin) and 
Zynlonta (loncastuximab tesirine)). DLBCL pipeline therapies include bispecific antibodies, ADCs, and CAR-T 
therapies. 
While there are many assets in development for both multiple myeloma and DLBCL including those with novel 
mechanisms of action, other than our EZM0414 product candidate which is in early clinical development, there are 
no therapies in clinical development that are SETD2 inhibitors.
There are a large number of companies developing or marketing treatments for cancer, including many major 
pharmaceutical and biotechnology companies. Companies that are developing new epigenetic treatments for cancer 
that target histone methyltransferases, or HMTs, and protein arginine methyltransferases, or PRMTs, include 
GlaxoSmithKline plc, or GSK, Johnson & Johnson, Pfizer, Inc., Daiichi Sankyo Company Limited, and 
Constellation Pharmaceuticals. Further, companies which are known to have EZH2 inhibitor programs or related 
programs include: Constellation Pharmaceuticals, developing an EZH2 inhibitor (CPI-0209, Phase 1/2 for solid 
tumors and lymphomas including DLBCL); Novartis AG, developing an EED inhibitor which indirectly blocks 
EZH2 (MAK683, Phase 1/2, advanced malignancies); Daiichi Sankyo, developing a EZH1/EZH2 dual inhibitor 
(valemetostat, DS-3201, Phase 1, relapsed or refractory non-Hodgkin lymphomas, AML, ALL as well as Phase 2 for 
small cell lung cancer); Pfizer, developing an EZH2 inhibitor (PF-06821497, Phase 1, relapsed or refractory small 
cell lung cancer, castration-resistant prostate cancer and FL); and Jiangsu Hengrui Pharmaceutical, developing an 
EZH2 inhibitor (SHR2554, Phase 2 for B-cell malignancies) in China. In addition, many companies are developing 
cancer therapeutics that work by targeting epigenetic mechanisms other than HMTs, including Celgene Corporation 
(now part of Bristol-Myers Squibb), or Celgene, Merck & Co., Inc., Secura Bio, Spectrum Pharmaceuticals, Otsuka 
Pharmaceuticals Co., Ltd, Foghorn Therapeutics, Forma Therapeutics and CellCentric, which are marketing cancer 
treatments that work by targeting epigenetic mechanisms other than HMTs. 
Our commercial opportunity could be reduced or eliminated if our competitors develop and commercialize products 
that are safer, more effective, have fewer or less severe side effects, are more convenient or are less expensive than 
tazemetostat for ES, FL or any other indication for which we may develop tazemetostat or any other products that 
we may develop. Our competitors also may obtain FDA or other regulatory approval for their products more rapidly 
than we may obtain approval for tazemetostat for any future indication for which we may develop tazemetostat or 
any other product we may develop, which could result in our competitors establishing a strong market position 
before we are able to enter the market. In addition, our ability to compete may be affected in many cases by insurers 
or other third-party payors seeking to encourage the use of generic products. Generic products are currently on the 
market for many of the indications that we are pursuing, and additional products are expected to become available 
on a generic basis over the coming years. We expect that tazemetostat will continue to be priced at a significant 
premium over competitive generic products.
Many of the companies against which we are competing or against which we may compete in the future have 
significantly greater financial resources and expertise in research and development, manufacturing, preclinical 
testing, conducting clinical trials, obtaining regulatory approvals and marketing approved products than we do. 
Mergers and acquisitions in the pharmaceutical and biotechnology industries may result in even more resources 
being concentrated among a smaller number of our competitors. Smaller and other early-stage companies may also 
prove to be significant competitors, particularly through collaborative arrangements with large and established 
companies. These third parties compete with us in recruiting and retaining qualified scientific and management 
personnel, establishing clinical trial sites and patient registration for clinical trials, as well as in acquiring 
technologies complementary to, or necessary for, our programs. 

52
Tazemetostat, EZM0414 and any other future product candidate that we commercialize may become subject to 
unfavorable pricing regulations, third-party reimbursement practices or healthcare reform initiatives, which 
could harm our business. 
The regulations that govern marketing approvals, pricing, coverage and reimbursement for new drug products vary 
widely from country to country. Current and future legislation may significantly change the approval requirements 
in ways that could involve additional costs and cause delays in obtaining approvals. Some countries require approval 
of the sale price of a drug before it can be marketed. In many countries, the pricing review period begins after 
marketing or product licensing approval is granted. In some foreign markets, prescription pharmaceutical pricing 
remains subject to continuing governmental control even after initial approval is granted. As a result, we might 
obtain marketing approval for a product in a particular country, but then be subject to price regulations that delay 
our commercial launch and market acceptance of the product, possibly for lengthy time periods, and negatively 
impact the revenues we are able to generate from the sale of the product in that country. Adverse pricing limitations 
may hinder our ability to recoup our investment in one or more product candidates, even if our product candidates 
obtain marketing approval. 
Our ability to successfully commercialize tazemetostat, EZM0414 or any future product candidates that we develop 
successfully also will depend in part on the extent to which insurance coverage and adequate reimbursement for 
these products and related treatments will be available from government health administration authorities, private 
health insurers and other organizations. Government authorities and third-party payors, such as private health 
insurers and health maintenance organizations, decide which medications they will pay for and establish 
corresponding reimbursement levels. A significant trend in the U.S. healthcare industry and elsewhere is cost 
containment. Government authorities and third-party payors continue to attempt to control costs by limiting 
coverage and the amount of reimbursement for particular medications. Increasingly, third-party payors are requiring 
that drug companies provide them with predetermined discounts from list prices and are challenging the prices 
charged for medical products. Coverage and reimbursement may not be available for any product that we 
commercialize and, even if these are available, the level of reimbursement may not be satisfactory to recoup our 
investment. Reimbursement may affect the demand for, or the price of, any product candidate for which we obtain 
marketing approval. Obtaining and maintaining adequate reimbursement for our products may be difficult. We may 
be required to conduct expensive pharmacoeconomic studies to justify coverage and reimbursement or the level of 
reimbursement relative to other therapies. If coverage and adequate reimbursement are not available or 
reimbursement is available only to limited levels, we may not be able to successfully commercialize any product 
candidate for which we obtain marketing approval. 
There may be significant delays in obtaining reimbursement for newly approved drugs, and coverage may be more 
limited than the purposes for which the drug is approved by the FDA or similar regulatory authorities outside of the 
United States. Moreover, eligibility for reimbursement does not imply that a drug will be paid for in all cases or at a 
rate that covers our costs, including research, development, manufacture, sale and distribution. Interim 
reimbursement levels for new drugs, if applicable, may also not be sufficient to cover our costs and may not be 
made permanent. Reimbursement rates may vary according to the intended use of the drug and the clinical setting in 
which it is used, may be based on reimbursement levels already set for lower cost drugs and may be incorporated 
into existing payments for other services. Net prices for drugs may be reduced by mandatory discounts or rebates 
required by government healthcare programs or private payors and by any future relaxation of laws that presently 
restrict imports of drugs from countries where they may be sold at lower prices than in the United States. Third-
party payors often rely upon Medicare coverage policy and payment limitations in setting their own reimbursement 
policies. Our inability to promptly obtain coverage and adequate reimbursement rates from both government-funded 
and private payors for any approved products that we develop could have a material adverse effect on our operating 
results, our ability to raise capital needed to commercialize products and our overall financial condition. 

53
Clinical drug development is a lengthy and expensive process, with an uncertain outcome. We may incur 
additional costs or experience delays in completing, or ultimately be unable to complete, the development and 
commercialization of tazemetostat, EZM0414 and any future product candidates. 
We are conducting multiple clinical trials of tazemetostat. In addition, we have initiated a first-in-human study of 
EZM0414 for the treatment of adult patients with relapsed or refractory multiple myeloma or relapsed or refractory 
DLBCL. The risk of failure is high. It is impossible to predict when or if any product candidates that we may 
develop will prove effective or safe in humans or will receive regulatory approval. Before obtaining marketing 
approval from regulatory authorities for the sale of any product candidate, we must complete preclinical 
development, manufacture, and then conduct extensive clinical trials to demonstrate the safety and efficacy of any 
product candidates in humans. 
Product candidates are subject to preclinical safety studies, which may be conducted prior to or concurrently with 
clinical testing, as well as continued clinical safety assessment throughout clinical testing. The outcomes of these 
safety studies or assessments may delay the launch of or patient enrollment in clinical studies. For example, in the 
course of our preclinical safety studies of tazemetostat, we observed the development of lymphoma in Sprague-
Dawley rats. As a result of these findings, coupled with our limited clinical experience in FL, at the time of the 
Investigational New Drug Application submission in December 2015, we were unable to conduct our Phase 2 trial 
of tazemetostat in FL patients in the United States until the beginning of 2017. In addition, in the second quarter of 
2018, following a safety report of a pediatric patient who developed a secondary T-cell lymphoma in our ongoing 
Phase 1 clinical trial of tazemetostat in pediatric patients, the FDA, the French National Agency for Medicines and 
Health Products Safety and Germany’s Federal Institute for Drugs and Medical Devices each placed a partial 
clinical hold on new patient enrollment in our ongoing clinical trials of tazemetostat. That partial clinical hold was 
lifted in September 2018 by the FDA, in November 2018 by Germany’s Federal Institute for Drugs and Medical 
Devices, and in January 2019 by the French National Agency for Medicines and Health Products Safety. In 
pharmaceutical development, many compounds that initially show promise in early-stage testing for treating cancer 
are later found to cause side effects that prevent further development of the compound. If we or our collaborators are 
unable to fully and adequately address matters such as these when they arise, we may be unable to conduct clinical 
trials of tazemetostat, EZM0414 or any future product candidates, our trials may be limited to certain patient 
populations or our ability to conduct other trials in the United States or in other countries may be delayed. 
Clinical testing is expensive, difficult to design and implement, can take many years to complete and is uncertain as 
to outcome. A failure of one or more clinical trials can occur at any stage of testing. The outcome of preclinical 
testing and early clinical trials may not be predictive of the success of later clinical trials, and interim results of a 
clinical trial do not necessarily predict final results. Moreover, preclinical and clinical data are often susceptible to 
varying interpretations and analyses, and many companies that have believed their product candidates performed 
satisfactorily in preclinical studies and clinical trials have nonetheless failed to obtain marketing approval of their 
products. 
We may experience numerous unforeseen events during, or as a result of, clinical trials that could delay or prevent 
our ability to receive marketing approval or commercialize tazemetostat, EZM0414 or any future product 
candidates, including: 

regulators or institutional review boards may not authorize us or our investigators to commence a 
clinical trial or conduct a clinical trial at a prospective trial site; 

we may experience delays in reaching, or fail to reach, agreement on acceptable clinical trial contracts 
or clinical trial protocols with prospective trial sites; 

clinical trials of our product candidates may produce negative or inconclusive results, and we may 
decide, or regulators may require us, to conduct additional clinical trials or abandon product 
development programs; 

preclinical testing may produce results based on which we may decide, or regulators may require us, to 
conduct additional preclinical studies before we proceed with certain clinical trials, limit the scope of 
our clinical trials, halt ongoing clinical trials or abandon product development programs; 

54

the number of patients required for clinical trials of our product candidates may be larger than we 
anticipate, enrollment in these clinical trials may be slower than we anticipate, or patients may drop out 
of these clinical trials at a higher rate than we anticipate; 

our third-party contractors may fail to comply with regulatory requirements or meet their contractual 
obligations to us in a timely manner, or at all; 

we may have to limit the scope of, suspend or terminate clinical trials of our product candidates for 
various reasons, including as a result of a finding that the patients are being exposed to unacceptable 
health risks; 

regulators or institutional review boards may require that we or our investigators suspend or terminate 
clinical research for various reasons, including noncompliance with regulatory requirements or a finding 
that the patients are being exposed to unacceptable health risks; 

the cost of clinical trials of our product candidates may be greater than we anticipate; 

the supply or quality of our product candidates or other materials necessary to conduct clinical trials of 
our product candidates may be insufficient, inadequate or delayed, including as a result of ongoing 
impacts of the COVID-19 pandemic; and 

our product candidates may have undesirable or unexpected side effects or other unexpected 
characteristics, causing us or our investigators, regulators or institutional review boards to suspend or 
terminate the trials. 
We and our CROs and CMOs, as well as clinical trial sites, may face disruptions related to our ongoing clinical 
trials, planned clinical trials or future clinical trials arising from manufacturing disruptions, staffing disruptions and 
limitations on our activities and the activities of our CROs and CMOs, and delays in the ability to obtain necessary 
institutional review board or other necessary site approvals, as well as other delays at clinical trial sites. We may 
also face limitations on enrollment and patients withdrawing from our clinical trials or not complying with the 
protocols, which could delay completion of our clinical trials or adversely affect the data generated by our clinical 
trials. The impact of these disruptions on our clinical development activities and plans is uncertain and may depend 
on the length of the disruptions.
If we are required to conduct additional clinical trials or other testing of tazemetostat, EZM0414 or any future 
product candidates beyond those that we currently contemplate, if we are unable to successfully complete clinical 
trials of tazemetostat, EZM0414 or any future product candidates or other testing, if the results of these trials or tests 
are not positive or are only modestly positive or if there are safety concerns, we may: 

be delayed in obtaining marketing approval for our product candidates; 

not obtain marketing approval at all; 

obtain approval for indications or patient populations that are not as broad as intended or desired; 

obtain approval with labeling or a risk evaluation mitigation strategy that includes significant use or 
distribution restrictions or safety warnings; 

be subject to additional post-marketing testing requirements; or 

have the product removed from the market after obtaining marketing approval. 
Our product development costs may also increase if we experience delays in clinical testing or in obtaining 
marketing approvals such as the delays caused by the partial clinical holds in the United States, France and 
Germany. We do not know whether any of our preclinical studies or clinical trials will continue or begin as planned, 
will need to be restructured or will be completed on schedule, or at all. Significant preclinical or clinical trial delays 
also could shorten any periods during which we may have the exclusive right to commercialize our product 
candidates or allow our competitors to bring products to market before we do and impair our ability to successfully 
commercialize our product candidates and may harm our business and results of operations. 

55
If we experience delays or difficulties in the enrollment of patients in clinical trials, our receipt of necessary 
regulatory approvals could be delayed or prevented. 
We may not be able to initiate or continue clinical trials for tazemetostat, EZM0414 or any future product candidates 
if we are unable to locate and enroll a sufficient number of eligible patients to participate in these trials as required 
by the FDA or similar regulatory authorities outside of the United States. In particular, if our product candidates are 
focused on specific patient populations, our ability to enroll eligible patients may be limited or may result in slower 
enrollment than we anticipate. For instance, our ongoing clinical trials of tazemetostat in adult and pediatric patients 
with INI1-negative tumors are targeting rare patient populations. In addition, some of our competitors have ongoing 
clinical trials, and may in the future initiate new clinical trials, for product candidates being developed for the same 
or similar diseases or indications as tazemetostat, EZM0414 or any future product candidates or that may treat the 
broader patient populations within which tazemetostat, EZM0414 or any future product candidates are being or may 
be developed for the treatment of a subset of identifiable patients with cancer, which could adversely affect 
enrollment in our trials, particularly in trials for rare disease indications, as patients who would otherwise be eligible 
for our clinical trials may instead enroll in clinical trials of our competitors’ product candidates. We have 
experienced some delays in clinical trial startup as a result of the COVID-19 pandemic, and as the COVID-19 
pandemic continues, patient recruitment and enrollment in our clinical trials may be adversely affected, delayed or 
interrupted. Patients may choose to withdraw from our studies or we may choose to or be required to pause 
enrollment and or patient dosing in our ongoing clinical trials in order to preserve health resources and protect trial 
participants. It is unknown how long these pauses or disruptions could continue.
Patient enrollment may be affected by other factors including: 

the severity of the disease under investigation; 

the rarity of the disease under investigation;

the eligibility criteria for the trial in question; 

the perceived risks and benefits of the product candidate under trial; 

the efforts to facilitate timely enrollment in clinical trials; 

the patient referral practices of physicians; 

the ability to monitor patients adequately during and after treatment; 

the proximity and availability of clinical trial sites for prospective patients; 

the potential costs to be incurred by prospective patients in order to participate, such as travel, missed 
work, and/or childcare;

the lack of scientific interest in the study; and

the ability to identify specific patient populations for molecularly defined study cohorts. 
Our inability to enroll a sufficient number of patients for our clinical trials would result in significant delays and 
could require us to abandon one or more clinical trials altogether. Enrollment delays in our clinical trials may result 
in increased development costs for tazemetostat, EZM0414 or any future product candidates and could delay or 
prevent our ability to obtain marketing approval, which may cause the value of our company to decline and limit our 
ability to obtain additional financing. 
Our research and development is focused on the creation of novel epigenetic therapies for patients with cancer, 
which is a rapidly evolving area of science, and the approach we are taking to discover and develop drugs is 
novel. 
The discovery of novel epigenetic therapies for patients with cancer is an emerging field, and the scientific 
discoveries that form the basis for our efforts to discover and develop tazemetostat and any future product 
candidates are relatively new. Although epigenetic regulation of gene expression plays an essential role in biological 
function, few drugs premised on epigenetics have been discovered. Moreover, those drugs based on an epigenetic 
mechanism that have received marketing approval, other than TAZVERIK, are in different target classes than the 

56
chromatin modifying protein, or CMP, inhibitors where our research and development is principally focused. 
Although preclinical studies suggest that genetic alterations can result in changes to the activity of CMPs making 
them oncogenic, and although the FDA has granted accelerated approval for TAZVERIK in ES and FL with 
continued approval contingent upon verification and description of clinical benefit in a confirmatory trial for each of 
the ES and FL indications, to date no company has translated broad biological observations regarding CMP 
inhibitors into systematic drug discovery, development and commercialization. We believe our early inhibitors of 
HMTs in clinical trials were the first molecules against these targets to enter clinical development. Therefore, we do 
not know if our approach of inhibiting HMTs or other CMPs to treat patients with cancer will be successful. 
We may expend our limited resources to pursue a particular product candidate or indication and fail to capitalize 
on tazemetostat, EZM0414 and any future product candidates or indications that may be more profitable or for 
which there is a greater likelihood of success. 
Because we have limited financial and managerial resources, we focus on research programs and product candidates 
that we identify for specific indications. As a result, we may forego or delay pursuit of opportunities with other 
product candidates or for other indications that later prove to have greater commercial potential. Our resource 
allocation decisions may cause us to fail to capitalize on viable commercial products or profitable market 
opportunities. Our spending on current and future research and development programs and on tazemetostat, 
EZM0414 and any future product candidates for specific indications may not yield any commercially viable 
products. If we do not accurately evaluate the commercial potential or target market for tazemetostat, EZM0414 or a 
particular future product candidate, we may relinquish valuable rights to that product candidate through 
collaboration, licensing or other royalty arrangements in cases in which it would have been more advantageous for 
us to retain sole development and commercialization rights to such product candidate. 
If we are required to develop a companion or complementary diagnostic and if we or our collaborators are 
unable to successfully develop diagnostics for tazemetostat, EZM0414 or any future therapeutic product 
candidates when needed, or experience significant delays in doing so, we may not achieve marketing approval or 
realize the full commercial potential of our therapeutic product candidates. 
We may develop, or we may work with collaborators, to develop diagnostics for tazemetostat, EZM0414 or any 
future therapeutic product candidates to identify patients for our clinical trials who have the specific cancers that we 
are seeking to treat as appropriate and when existing, available technology may not be sufficient to identify those 
patients. We do not have experience or capabilities in developing or commercializing diagnostics and plan to rely in 
large part on third parties to perform these functions. For example, we have entered into an agreement with Roche 
Sequencing Solutions, or Roche Sequencing, to develop and commercialize a companion diagnostic for use with 
tazemetostat for non-Hodgkin lymphoma, or NHL, patients with EZH2 activating mutations. Companion or 
complementary diagnostics are subject to regulation by the FDA and similar regulatory authorities outside of the 
United States as medical devices and require separate regulatory approval prior to commercialization. If any third 
parties that we engage to assist us are unable to successfully develop companion or complementary diagnostics that 
are needed for our therapeutic product candidates, or experience delays in doing so: 

the development of our therapeutic product candidates may be adversely affected if we are unable to 
appropriately select patients for enrollment in our clinical trials; 

our therapeutic product candidates may not receive marketing approval if their safe and effective use 
depends on a companion or complementary diagnostic; and 

we may not realize the full commercial potential of any therapeutic product candidates that receive 
marketing approval if, among other reasons, we are unable to appropriately identify patients with the 
specific genetic alterations targeted by our therapeutic product candidates. 
If any of these events were to occur, our business would be harmed, possibly materially. 

57
We may not be successful in our efforts to use and expand our proprietary drug discovery platform to build a 
pipeline of product candidates. 
A key element of our strategy is to utilize our drug discovery platform to progress preclinical efforts and pursue 
additional product candidates to expand our pipeline of inhibitors against CMPs for the treatment of a variety of 
different types of cancer. We may not be able to develop product candidates that are safe and effective CMP 
inhibitors. Even if we are successful in continuing to build our pipeline, the potential product candidates that we 
identify may not be suitable for clinical development, including as a result of being shown to have harmful side 
effects or other characteristics that indicate that they are unlikely to be products that will receive marketing approval 
and achieve market acceptance. If we do not successfully develop and commercialize product candidates based upon 
our technological approach, we will not be able to obtain product revenues for additional products in future periods, 
which likely would result in significant harm to our financial position and adversely affect our stock price. 
Product liability lawsuits against us could cause us to incur substantial liabilities and to limit commercialization 
of any products that we may develop. 
We face an inherent risk of product liability exposure related to the testing and utilization of tazemetostat in 
connection with the clinical testing and commercial use of tazemetostat and with respect to any other product 
candidates that we develop or commercialize. If we cannot successfully defend ourselves against claims that our 
product candidates or products caused injuries, we will incur substantial liabilities. Regardless of merit or eventual 
outcome, liability claims may result in: 

decreased demand for any product candidates or products that we may develop; 

injury to our reputation and significant negative media attention; 

withdrawal of clinical trial participants or patients; 

significant costs to defend any related litigation; 

substantial monetary awards to trial participants or patients; 

loss of revenue; 

reduced resources of our management to pursue our business strategy; and 

the inability to commercialize any products that we may develop. 
We currently hold $30.0 million in product liability insurance coverage in the aggregate, with a per incident limit of 
$30.0 million, which may not be adequate to cover all liabilities that we may incur. We will need to increase our 
insurance coverage as we expand our clinical trials and as we continue to commercialize TAZVERIK, or any other 
product candidate that we develop. Insurance coverage is increasingly expensive. We may not be able to maintain 
insurance coverage at a reasonable cost or in an amount adequate to satisfy any liability that may arise.  
Enhanced governmental and private scrutiny over, or investigations or litigation involving, pharmaceutical 
manufacturer donations to patient assistance programs offered by charitable foundations may require us to 
modify our patient support programs and could negatively impact our business practices, harm our reputation, 
divert the attention of management and increase our expenses.
To help patients afford tazemetostat, we have implemented a patient assistance program. These types of programs, 
designed to assist patients in affording pharmaceuticals, have become the subject of scrutiny. In recent years, some 
pharmaceutical manufacturers were named in class action lawsuits challenging the legality of components of their 
patient assistance programs and their support of independent charitable foundations in connection with such 
programs under a variety of federal and state laws. Our patient assistance program could become the target of 
similar litigation. In addition, certain state and federal enforcement authorities and members of Congress have 
initiated inquiries about co-pay assistance programs. Some state legislatures have also been considering proposals 
that would restrict or ban co-pay coupons.

58
Further, numerous organizations, including pharmaceutical manufacturers, have received subpoenas from the U.S. 
Department of Justice, or DOJ, and other enforcement authorities seeking information related to their patient 
assistance programs and support, and certain of these organizations have entered into, or have otherwise agreed to, 
significant civil settlements with applicable enforcement authorities. In connection with these civil settlements, the 
U.S. government has and may in the future require the affected companies to enter into complex corporate integrity 
agreements that impose significant reporting and other requirements on those companies. We cannot ensure that our 
compliance controls, policies and procedures will be sufficient to protect against acts of our employees, business 
partners or vendors that may potentially violate the laws or regulations of the jurisdictions in which we operate. 
Regardless of whether we have complied with the law, a government investigation could negatively impact our 
business practices, harm our reputation, divert the attention of management and increase our expenses. 
Risks Related to Our Financial Position and Need for Additional Capital 
We have incurred significant losses since our inception. We expect to incur losses over the next several years and 
may never achieve or maintain profitability. 
Since inception, we have incurred significant operating losses. Our net loss was $251.1 million for the year ended 
December 31, 2021, $231.7 million for the year ended December 31, 2020, and $170.3 million for the year ended 
December 31, 2019. As of December 31, 2021, we had an accumulated deficit of $1,239.8 million. To date, we have 
generated only limited revenue from sales of TAZVERIK and have not obtained marketing approval of any other 
product. We have financed our operations primarily through our collaborations, our public offerings, private 
placements of our common and preferred stock, our loan facility with BioPharma Credit Investments V (Master) LP, 
BPCR Limited Partnership and BioPharma Credit PLC, and other funding transactions. We have devoted 
substantially all of our financial resources and efforts to research and development, including clinical and preclinical 
studies, seeking marketing approval for product candidates and building our commercial organization with respect to 
TAZVERIK in the indications for which we have received accelerated approval from the FDA. We are continuing to 
develop tazemetostat for additional indications and to seek to discover and develop EZM0414 and other product 
candidates. We expect to continue to incur significant expenses and operating losses over the next several years. Our 
net losses may fluctuate significantly from quarter to quarter and year to year. 
We anticipate that we will continue to incur significant expenses if and as we: 

continue to build and refine our sales, marketing and distribution infrastructure and scale up external 
manufacturing capabilities to support the ongoing commercialization of TAZVERIK and the 
commercial launch of any other product candidate that is approved;

grow our medical affairs organization to provide medical support for tazemetostat and any other product 
candidate that is approved;

conduct our Phase 1b/3 confirmatory trials in ES and FL;

design and conduct new and ongoing monotherapy and combination trials of tazemetostat in FL;

conduct clinical trials or support investigator-sponsored trials to evaluate tazemetostat as a monotherapy 
or in combinations in additional indications;

conduct our Phase 1/1b clinical trial of EZM0414 for the treatment of R/R multiple myeloma and 
DLBCL patients;

pay any milestone payments provided for and achieved under the amended and restated collaboration 
and license agreement with Eisai Co Ltd, or Eisai; 

pay interest and principal associated with our amended and restated loan agreement with BioPharma 
Credit Investments V (Master) LP, BPCR Limited Partnership and BioPharma Credit PLC, or the 
Amended and Restated Loan Agreement;

continue the research and development of our other product candidates; 

seek to discover and develop additional product candidates or to expand our product candidates into 
additional lines of treatment; 

59

prepare NDA submissions as we seek regulatory approvals for any product candidates that successfully 
complete clinical trials; 

maintain, expand and protect our intellectual property portfolio; 

hire additional clinical, quality control, manufacturing and scientific personnel; and 

add operational, financial and management information systems and personnel, including personnel to 
support our product development and planned future commercialization efforts. 
To become and remain profitable, we must generate significant revenue. The ability to generate this revenue 
requires us to successfully commercialize TAZVERIK in ES and FL and in additional indications for which we may 
develop and obtain approval for tazemetostat, which requires us to be effective in a range of challenging activities. 
We may never succeed in these activities and, even if we do, may never generate revenues that are significant 
enough to achieve profitability. Because of the numerous risks and uncertainties associated with the development 
and commercialization of pharmaceutical products, we are unable to accurately predict the timing or amount of 
increased expenses or when, or if, we will be able to achieve profitability.
Even if we do achieve profitability, we may not be able to sustain or increase profitability on a quarterly or annual 
basis. Our failure to become and remain profitable would depress the value of our company and could impair our 
ability to raise capital, expand our business, maintain our research and development efforts, diversify our product 
offerings or even continue our operations. A decline in the value of our company could cause our stockholders to 
lose all or part of their investment in our company. 
We will need substantial additional funding. If we are unable to raise capital when needed, we could be forced to 
delay, reduce or eliminate our product development programs or commercialization efforts. 
We expect our expenses to increase in connection with our ongoing activities, particularly as we expect to incur 
significant commercialization expenses related to product manufacturing, marketing, sales, and distribution. In 
addition, we expect our expenses to increase as we fund our tazemetostat development program; make any milestone 
and royalty payments provided for and achieved under the amended and restated collaboration and license 
agreement with Eisai; pay interest and principal associated with the Amended and Restated Loan Agreement; and 
continue research and development and initiate clinical trials of, and seek regulatory approval for, EZM0414 or any 
future product candidates. Accordingly, we may need to obtain substantial additional funding in connection with our 
continuing operations. If we are unable to raise capital when needed or on acceptable terms, we could be forced to 
delay, reduce or eliminate our research and development programs or our commercialization efforts. 
Based on our current operating plan, we expect that our existing cash, cash equivalents and marketable securities as 
of December 31, 2021, together with the $79.5 million in net proceeds raised from the common stock offering in 
January 2022, and expected cash generated from product sales, will be sufficient to fund planned operating expenses 
and capital expenditure requirements and pay debt service obligations as they become due, into the third quarter of 
2023, without incorporating potential milestone payments, expense reimbursements from existing collaboration 
agreements or any future business development activities. We have based these expectations on assumptions that 
may prove to be wrong, such as the revenue that we expect to generate from the sale of our products, and we could 
use our capital resources sooner than we expect. Our future capital requirements will depend on many factors, 
including the following, as well as the uncertain impact of the COVID-19 pandemic on these factors: 

the costs of commercialization activities, including product manufacturing, marketing, sales and 
distribution and patient support programs for tazemetostat or any of our product candidates; 

revenue received from commercial sales of TAZVERIK;

the progress and results of our ongoing and planned clinical trials of tazemetostat; 

the number and development requirements of additional indications for tazemetostat and other product 
candidates that we determine to pursue, including the scope, progress, results and costs of discovery 
research, preclinical development, laboratory testing and clinical trials for such product candidates; 

60

the costs, timing and outcome of regulatory review of tazemetostat and other product candidates we may 
pursue; 

royalties payable by us on sales of TAZVERIK under our amended and restated collaboration and 
license agreement with Eisai;

milestones, option exercise fees, license fees, and other revenues, if any, we may receive under 
collaboration agreements; 

the revenue, if any, received from commercial sales of our product candidates for which we receive 
marketing approval; 

the costs and timing of preparing, filing and prosecuting patent applications, maintaining and enforcing 
our intellectual property rights, defending any intellectual property-related claims, and challenging the 
intellectual property rights of others; 

the extent to which we acquire or in-license other products and technologies; and

interest and principal payments under the Amended and Restated Loan Agreement. 
Identifying potential product candidates and conducting preclinical testing and clinical trials is a time-consuming, 
expensive and uncertain process that takes years to complete, and even if regulatory approval is obtained, we may 
never achieve commercial success. Accordingly, we may need to continue to rely on additional financing to achieve 
our business objectives. Adequate additional financing may not be available to us on acceptable terms, or at all. In 
addition, we may seek additional capital due to favorable market conditions or strategic considerations, even if we 
believe we have sufficient funds for our current or future operating plans. 
Raising additional capital may cause dilution to our stockholders, restrict our operations or require us to 
relinquish rights to our technologies or product candidates. 
Until such time, if ever, as we can generate substantial product revenues, we expect to finance our cash needs 
through a combination of equity offerings, debt financings and license and development agreements with 
collaboration partners. We do not have any committed external source of funds. To the extent that we raise 
additional capital through the sale of equity or convertible debt securities, the ownership interest of our existing 
stockholders will be diluted, and the terms of these securities may include liquidation or other preferences that 
adversely affect the rights of our common stockholders. We may be limited in our ability to raise additional capital 
through the sale of equity as we have a limited number of authorized shares that are not issued and outstanding or 
reserved for future issuance. Additional debt financing and preferred equity financing, if available, may involve 
agreements that include covenants limiting or restricting our ability to take specific actions, such as incurring 
additional debt, making capital expenditures or declaring dividends. Our existing indebtedness and the pledge of our 
assets as collateral limit our ability to obtain additional debt financing. 
If we raise additional funds through collaborations, strategic alliances or marketing, distribution or licensing 
arrangements with third parties, we may have to relinquish valuable rights to our technologies, future revenue 
streams, research programs or product candidates or grant licenses on terms that may not be favorable to us. If we 
are unable to raise additional funds through equity or debt financings when needed, we may be required to delay, 
limit, reduce or terminate our product development or commercialization efforts or grant rights to develop and 
market product candidates that we would otherwise prefer to develop and market ourselves. 
Our indebtedness resulting from our Amended and Restated Loan Agreement could adversely affect our financial 
condition or restrict our future operations.
In November 2019, we entered into the Loan Agreement with BioPharma Credit PLC, or the Collateral Agent, and 
BioPharma Credit Investments V (Master) LP and BPCR Limited Partnership (as transferee of BioPharma Credit 
Investments V (Master) LP’s interest as a lender), or the Lenders, providing for up to $70.0 million in secured term 
loans to be advanced in up to three tranches, or the Loan Agreement, of which $25.0 million was drawn by us in 

61
November 2019, $25.0 million was drawn by us in March 2020, and $20.0 million was drawn by us in June 2020. 
The maturity date of the first three tranches is November 18, 2024, unless paid earlier.
In November 2020, we entered into an Amended and Restated Loan Agreement with the Collateral Agent and the 
Lenders, amending and restating the Loan Agreement to provide for, among other things, an additional secured term 
loan facility of $150.0 million, or the Tranche D Loan. In November 2020, we drew the $150.0 million Tranche D 
Loan. The maturity date of the Tranche D Loan is November 18, 2026, unless terminated earlier. 
Subject to customary exceptions and exclusions, all obligations under the Amended and Restated Loan Agreement 
are secured pursuant to the terms of the Amended and Restated Loan Agreement, a guaranty and security agreement 
between us, certain of our subsidiaries, and the Collateral Agent, or the Pledge Agreement, and intellectual property 
and security agreements between us and Collateral Agent, or the IP Security Agreements. Under the Amended and 
Restated Loan Agreement, the Pledge Agreement, and the IP Security Agreements, we provided to the Lenders a 
perfected, first-priority security interest in all of our personal property and a perfected, first-priority security interest 
in substantially all of our intellectual property related to tazemetostat.
A failure to comply with the conditions of the Amended and Restated Loan Agreement could result in an event of 
default. An event of default under the term loan facility includes, among other things, a failure to pay any amount 
due under the Amended and Restated Loan Agreement as well as the occurrence of events that could reasonably be 
expected to result in a material adverse change. In the event of an acceleration of amounts due under the Amended 
and Restated Loan Agreement as a result of an event of default, we may not have sufficient funds or may be unable 
to arrange for additional financing to repay the term loans or to make any accelerated payments.
Risks Related to Our Dependence on Third Parties 
Our existing therapeutic collaborations are important to our business, and future collaborations may also be 
important to us. If we are unable to maintain any of these collaborations, or if these collaborations are not 
successful, our business could be adversely affected. 
Our resources for drug development are limited and we continue to build our sales, marketing, medical affairs and 
supply chain infrastructure. Accordingly, we have entered into therapeutic collaborations with other companies that 
we believe can contribute to our ability to rapidly develop and commercialize TAZVERIK and any product 
candidates we may identify and develop, including our license agreement with HutchMed. Our collaborations have 
provided us with important funding for our development programs and product platform and we expect to receive 
additional funding under these collaborations in the future. Our existing therapeutic collaborations, and any future 
collaborations we enter into, may pose a number of risks, including the following: 

collaborators have significant discretion in determining the efforts and resources that they will apply to 
these collaborations; 

collaborators may not have the ability or the development capabilities to perform their obligations as 
expected, including as a result of the impact of the COVID-19 pandemic on our collaborators’ 
operations or business; 

collaborators may not pursue commercialization of any product candidates that achieve regulatory 
approval or may elect not to continue or renew development or commercialization programs based on 
clinical trial results, changes in the collaborators’ strategic focus or available funding, or external 
factors, such as an acquisition, that may divert resources or create competing priorities; 

collaborators may delay clinical trials, provide insufficient funding for a clinical trial program, stop a 
clinical trial or abandon a product candidate, not initiate or delay initiation of clinical trials, pause or 
stop enrollment in a clinical trial, terminate an ongoing clinical trial, repeat or conduct new clinical trials 
or require a new formulation of a product candidate for clinical testing; 

collaborators could independently develop, or develop with third parties, products that compete directly 
or indirectly with our products and product candidates if the collaborators believe that the competitive 

62
products are more likely to be successfully developed or can be commercialized under terms that are 
more economically attractive than ours; 

product candidates discovered in collaboration with us may be viewed by our collaborators as 
competitive with their own product candidates or products, which may cause collaborators to cease to 
devote resources to the commercialization of our product candidates; 

a collaborator may fail to comply with applicable regulatory requirements regarding the development, 
manufacture, distribution or marketing of a product candidate or product; 

a collaborator with marketing and distribution rights to one or more of our product candidates that 
achieve regulatory approval may not commit sufficient resources to the marketing and distribution of 
such product or products; 

disagreements with collaborators, including disagreements over proprietary rights, contract 
interpretation or the preferred course of development, might cause delays or terminations of the 
research, development or commercialization of product candidates, might lead to additional 
responsibilities for us with respect to product candidates, or might result in litigation or arbitration, any 
of which would be time-consuming and expensive; 

collaborators may not properly maintain or defend our intellectual property rights or may use our 
proprietary information in such a way as to invite litigation that could jeopardize or invalidate our 
intellectual property or proprietary information or expose us to potential litigation; 

collaborators may infringe the intellectual property rights of third parties, which may expose us to 
litigation and potential liability; and 

collaborations may be terminated for the convenience of the collaborator, and, if terminated, we could 
be required to raise additional capital to pursue further development or commercialization of the 
applicable product candidates. 
If our therapeutic collaborations do not result in the successful development and commercialization of products or if 
one of our collaborators terminates its collaboration with us, we may not receive the funding under the collaboration 
that we anticipated. If we do not receive the funding we expect under these agreements, our development of our 
product platform and product candidates could be delayed and we may need additional resources to develop product 
candidates and our product platform. All of the risks relating to product development, regulatory approval and 
commercialization described in this Annual Report on Form 10-K also apply to the activities of our therapeutic 
collaborators. 
Our existing therapeutic collaborations contain restrictions on our ability to engage in activities that are the subject 
of the collaboration with third parties for specified periods of time. These restrictions may have the effect of 
preventing us from undertaking development and other efforts that may appear to be attractive to us. 
Additionally, subject to its contractual obligations to us, if a collaborator of ours is involved in a business 
combination, the collaborator might deemphasize or terminate the development or commercialization of any product 
candidate licensed to it by us. If one of our collaborators terminates its agreement with us, we may find it more 
difficult to attract new collaborators and our perception in the business and financial communities could be 
adversely affected. In the fourth quarter of 2021, Glaxo Group Limited, an affiliate of GSK, terminated its 
collaboration with us without cause, effective March 16, 2022.
For some of our product candidates or for some CMP targets, we may in the future collaborate with pharmaceutical 
and biotechnology companies for development and potential commercialization of therapeutic products. We face 
significant competition in seeking appropriate collaborators. Our ability to reach a definitive agreement for a 
collaboration will depend, among other things, upon our assessment of the collaborator’s resources and expertise, 
the terms and conditions of the proposed collaboration and the proposed collaborator’s evaluation of a number of 
factors. If we are unable to reach agreements with suitable collaborators on a timely basis, on acceptable terms, or at 
all, we may have to increase our expenditures and undertake development or commercialization activities for the 
product candidate or program on our own or at our own expense or curtail the development of a product candidate, 
reduce or delay its development program or one or more of our other development programs, delay its potential 
commercialization or reduce the scope of any sales or marketing activities. If we elect to fund and undertake 

63
development or commercialization activities on our own, we may need to obtain additional expertise and additional 
capital, which may not be available to us on acceptable terms or at all. If we do not have sufficient funds or expertise 
to undertake the necessary development and commercialization activities, we may not be able to further develop our 
product candidates or bring them to market or continue to develop our product platform and our business may be 
materially and adversely affected.
Failure of our third-party collaborators to successfully commercialize diagnostics, developed for use with our 
therapeutic product candidates, if and when needed, could harm our ability to commercialize these product 
candidates. 
We do not plan to develop diagnostics internally and, as a result, if diagnostics are needed, we will be dependent on 
the efforts of our third-party collaborators to successfully commercialize diagnostics when existing, available 
technology may not be sufficient to identify patients for treatment with our therapeutic product candidates. For 
example, Roche Sequencing has developed a companion diagnostic kit for detecting activating mutations in EZH2 
in the tazemetostat NHL program. Our collaborators: 

may not perform their obligations as expected or have difficulty responding to accelerated approval 
timelines alongside the therapeutic product development; 

may encounter production difficulties that could constrain the supply of the diagnostics; 

may encounter delays or have difficulty obtaining regulatory approval for the diagnostic in target 
markets; 

may have difficulties gaining acceptance of the use of the diagnostics in the clinical community; 

may not pursue commercialization of any diagnostics that achieve regulatory approval; 

may elect not to continue or renew commercialization programs based on changes in the collaborators’ 
strategic focus or available funding, or external factors such as an acquisition, that divert resources or 
create competing priorities; 

may not commit sufficient resources to the marketing and distribution of such product or products; and 

may terminate their relationship with us. 
If required diagnostics for use with our therapeutic product candidates fail to gain market acceptance, our ability to 
derive revenues from sales of our therapeutic product candidates could be harmed. If our collaborators fail to 
commercialize these diagnostics, we may not be able to enter into arrangements with another diagnostic company to 
obtain supplies of an alternative diagnostic test for use in connection with our therapeutic product candidates or do 
so on commercially reasonable terms, which could adversely affect and delay the development or commercialization 
of our therapeutic product candidates. 
We rely, and expect to continue to rely, on third parties to conduct our clinical trials, and those third parties may 
not perform satisfactorily, including failing to meet deadlines for the completion of such trials. 
We currently rely on third-party clinical research organizations to conduct our ongoing clinical trials. We do not 
plan to independently conduct clinical trials of tazemetostat, EZM0414 or any future product candidates. We expect 
to continue to rely on third parties, such as clinical research organizations, research collaborative groups, clinical 
data management organizations, medical institutions and clinical investigators, to conduct our clinical trials. These 
agreements might terminate for a variety of reasons, including a failure to perform by the third parties. If we need to 
enter into alternative arrangements, our product development activities might be delayed. 
Our reliance on these third parties for research and development activities will reduce our control over these 
activities but will not relieve us of our responsibilities. For example, we will remain responsible for ensuring that 
each of our clinical trials is conducted in accordance with the general investigational plan and protocols for the trial. 
Moreover, the FDA requires us to comply with standards, commonly referred to as good clinical practices, for 
conducting, recording and reporting the results of clinical trials to assure that data and reported results are credible 
and accurate and that the rights, integrity and confidentiality of trial participants or patients are protected. We also 
are required to register ongoing clinical trials and post the results of completed clinical trials on a government-

64
sponsored database, ClinicalTrials.gov, within specified timeframes. Failure to do so can result in fines, adverse 
publicity and civil and criminal sanctions. 
Furthermore, these third parties may also have relationships with other entities, some of which may be our 
competitors. If these third parties do not successfully carry out their contractual duties, meet expected deadlines or 
conduct our clinical trials in accordance with regulatory requirements or our stated protocols, we will not be able to 
obtain, or may be delayed in obtaining, marketing approvals for our product candidates and will not be able to, or 
may be delayed in our efforts to, successfully commercialize our product candidates. 
We also expect to continue to rely on other third parties to store and distribute drug supply for our clinical trials and 
our commercial operations. Any performance failure on the part of any such distributor could delay clinical 
development or marketing approval of our product candidates or commercialization of our products, producing 
additional losses and depriving us of potential product revenue. 
We contract with third parties for the manufacture of tazemetostat for commercialization and clinical testing and 
EZM0414 for clinical testing, and expect to contract with third parties for the manufacture of any other product 
candidates that we develop for preclinical and clinical testing and for commercialization. This reliance on third 
parties increases the risk that we will not have sufficient quantities of our product candidates or products or such 
quantities at an acceptable cost or quality, which could delay, prevent or impair our development or 
commercialization efforts. 
We do not have any manufacturing facilities and rely, and expect to continue to rely, on third parties for the 
manufacture of our product candidates for preclinical and clinical testing, as well as for commercial manufacture of 
tazemetostat and any other product candidates we develop that receive marketing approval. This reliance on third 
parties increases the risk that we will not have sufficient quantities of tazemetostat, EZM0414 or any other product 
candidate or such quantities at an acceptable cost or quality, which could delay, prevent or impair our development 
or commercialization efforts. 
We may be unable to establish any agreements with third-party manufacturers or to do so on a timely basis or on 
acceptable terms. Even if we are able to establish agreements with third-party manufacturers, reliance on such third-
party manufacturers entails additional risks, including: 

reliance on the third-party for regulatory compliance and quality assurance; 

the possible breach of the manufacturing agreement by the third party; 

the possible misappropriation of our proprietary information, including our trade secrets and know-how; 
and 

the possible termination or nonrenewal of the agreement by the third party at a time that is costly or 
inconvenient for us. 
Third-party manufacturers may not be able to comply with current good manufacturing practices, or cGMP, 
regulations or similar regulatory requirements outside of the United States. Our failure, or the failure of our third-
party manufacturers, to comply with applicable regulations could result in sanctions being imposed on us, including 
clinical holds, fines, injunctions, civil penalties, delays, suspension or withdrawal of approvals, license revocation, 
seizures or recalls of product candidates or products, operating restrictions and criminal prosecutions, any of which 
could significantly and adversely affect supplies of our products. 
Tazemetostat, EZM0414 and any other product candidate that we may develop may compete with other product 
candidates and products for access to manufacturing facilities. There are a limited number of manufacturers that 
operate under cGMP regulations and that might be capable of manufacturing for us. 
Any performance failure on the part of our existing or future manufacturers could delay clinical development, or 
marketing approval, and could adversely impact our ability to sell our approved products. We have already built 
additional redundancy in our supply chain and have plans to continue to qualify additional raw material 
manufacturers in our TAZVERIK supply chain. If our current contract manufacturers cannot perform as agreed, we 

65
may be required to replace such manufacturers. We expect that we would incur added costs and delays in identifying 
and qualifying any such replacement. 
Our current and anticipated future dependence upon others for the manufacture of our product candidates or 
products may adversely affect our future profit margins and our ability to commercialize any products that receive 
marketing approval on a timely and competitive basis. 
Risks Related to Our Intellectual Property 
If we are unable to obtain, maintain and enforce patent protection for our technology, products and product 
candidates or if the scope of the patent protection obtained is not sufficiently broad, our competitors could 
develop and commercialize technology, products or product candidates similar or identical to ours, and our 
ability to successfully develop and commercialize our technology, products or product candidates may be 
impaired. 
Our success depends in large part on our ability to obtain, maintain and enforce patent protection in the United 
States and foreign jurisdictions with respect to our proprietary technology, products and product candidates. We 
seek to protect our proprietary position by filing patent applications in the United States and abroad related to our 
novel technology, products and product candidates. 
The patent prosecution process is expensive, time-consuming and complex, and we may not be able to file, 
prosecute or maintain all necessary or desirable patent applications at a reasonable cost or in a timely manner. It is 
also possible that we may fail to identify patentable aspects of our research and development output before it is too 
late to obtain patent protection. Moreover, in some circumstances, we do not have the right to control the 
preparation, filing and prosecution of patent applications, or to maintain the patents, covering technology that we 
license from third parties. Therefore, these in-licensed patents and applications may not be prepared, filed, 
prosecuted or maintained in a manner consistent with the best interests of our business. 
Although we enter into non-disclosure and confidentiality agreements with parties who may have access to 
confidential or patentable aspects of our research and development output, such as our employees, collaborators, 
contract research organizations, contract manufacturers, consultants, advisors and other third parties, any of these 
parties may breach the agreements and disclose such output before a patent application is filed, thereby potentially 
jeopardizing our ability to seek patent protection. 
The patent position of biotechnology and pharmaceutical companies generally is highly uncertain, involves complex 
legal and factual questions and has in recent years been the subject of much litigation. In addition, the scope of our 
patent protection outside of the United States is uncertain, and laws of foreign jurisdictions may not protect our 
rights to the same extent as the laws of the United States. For example, European patent law restricts the 
patentability of methods of treatment of the human body more than United States law does. With respect to our 
patent rights, we cannot predict whether the patent applications we and/or our licensors are currently pursuing will 
issue as patents in any particular jurisdiction or whether the claims of any issued patents will provide sufficient 
protection from competitors. In addition, publications of discoveries in the scientific literature often lag behind the 
actual discoveries, and patent applications in the United States and foreign jurisdictions are typically not published 
until 18 months after filing, or in some cases at all. Therefore, neither we nor our licensors can know with certainty 
whether we were the first to make the inventions claimed in the patents or pending patent applications, or that we or 
our licensors were the first to file for patent protection of such inventions. As a result, the issuance, scope, validity, 
enforceability and commercial value of our patent rights are highly uncertain. Our pending and future patent 
applications may not result in patents being issued which protect our technology, products or product candidates, in 
whole or in part, or which effectively prevent others from developing or commercializing competitive technologies, 
products and product candidates. Changes in either the patent laws or interpretation of the patent laws in the United 
States and foreign jurisdictions may diminish the value of our patent rights or narrow the scope of our patent 
protection. 
Moreover, we may be subject to a third-party preissuance submission of prior art to the U.S. Patent and Trademark 
Office, or USPTO, or become involved in opposition, derivation, reexamination, inter partes review, post-grant 
review or interference proceedings challenging our patent rights or the patent rights of others. For example, we are 

66
involved in an opposition proceeding against one of our European patents, the claims of which cover a method for 
determining whether a cancer patient is a candidate for treatment with an EZH2 inhibitor based on their EZH2 
mutation status. An adverse determination in any such submission, proceeding or litigation could reduce the scope 
of, or invalidate, our patent rights, allow third parties to commercialize our technology or products and compete 
directly with us, without payment to us, or result in our inability to manufacture or commercialize our technology or 
products without infringing, misappropriating or otherwise violating third-party patent rights. In addition, if the 
breadth or strength of protection provided by our owned and/or in-licensed patents and patent applications is 
threatened, it could dissuade companies from collaborating with us to license, develop or commercialize our 
technology, products or product candidates. Furthermore, such proceedings also may result in substantial cost and 
divert the time and attention of our management and employees, even if the eventual outcome is favorable to us.
In addition, the coverage claimed in a patent application may be significantly reduced before the patent is issued, 
and its scope may be reinterpreted after issuance. Even if our owned and/or in-licensed patent applications issue as 
patents, they may not issue in a form that will provide us with any meaningful protection, prevent competitors from 
competing with us or otherwise provide us with any competitive advantage. The issuance of a patent is not 
conclusive as to its inventorship, scope, validity or enforceability, and our owned and/or in-licensed patents may be 
challenged in the courts or patent offices in the United States and abroad. Such challenges may result in loss of 
exclusivity or in patent claims being narrowed, invalidated or held unenforceable, in whole or in part, which could 
limit our ability to stop others from using or commercializing similar or identical technology and products, or limit 
the duration of the patent protection of our technology and products. Such proceedings also may result in substantial 
cost and divert the time and attention of our management and employees, even if the eventual outcome is favorable 
to us. Given the amount of time required for the development, testing and regulatory review of new product 
candidates, patents protecting such candidates might expire before or shortly after such candidates are 
commercialized. Furthermore, our competitors may be able to circumvent our owned and/or in-licensed patents by 
developing similar or alternative technologies or products in a non-infringing manner. As a result, our owned and/or 
in-licensed patent portfolio may not provide us with sufficient rights to exclude others from commercializing 
technology and/or products similar or identical to any of our technology and products.
Moreover, some of our owned and/or in-licensed patents and patent applications are, and may in the future be, co-
owned with third parties. If we are unable to obtain an exclusive license to any such third-party co-owners’ interest 
in such patents or patent applications, such co-owners may be able to license their rights to other third parties, 
including our competitors, and our competitors could market competing technology and products. In addition, we 
may need the cooperation of any such co-owner of our patents in order to enforce such patents against third parties, 
and such cooperation may not be provided to us. 
If we do not obtain patent term extension for our products, our business may be materially harmed.
In the United States, depending upon the timing, duration and specifics of any FDA marketing approval of a product 
candidate, the patent term of a patent that covers an FDA-approved product may be eligible for patent term 
extension, which permits patent term restoration as compensation for the patent term lost during the FDA regulatory 
review process. The Drug Price Competition and Patent Term Restoration Act of 1984, also known as the Hatch-
Waxman Act, permits a patent term extension of up to five years beyond the expiration of the patent for those claims 
covering the approved product, a method for using it or a method for manufacturing such product. Similar 
provisions are available in Europe and other foreign jurisdictions to extend the term of a patent that covers an 
approved drug. We have applied for patent term extension on a patent that covers the TAZVERIK drug substance 
based on the regulatory review of TAZVERIK for the treatment of adult and pediatric patients aged 16 years and 
older with metastatic or locally advanced ES not eligible for complete resection. In the future, if and when any 
additional product candidates receive FDA approval, we expect to apply for patent term extensions on patents 
covering those approved products. Similarly, in foreign jurisdictions where we have obtained regulatory approval, 
we intend to seek patent term extensions for any applicable issued patent rights if such extensions are available, 
however there is no guarantee that the applicable authorities will agree with our assessment of whether such 
extensions should be granted, and even if granted, the length of any such extensions. We may not be granted an 
extension because of, for example, failing to exercise due diligence during the testing phase or regulatory review 
process, failing to apply within applicable deadlines, failing to apply prior to expiration of the relevant patent(s), or 
otherwise failing to satisfy applicable requirements. If we are unable to obtain any patent term extension or the term 
of any such extension is less than we request, our competitors may obtain approval of competing products following 

67
the expiration of our patent rights, and our business, financial condition, results of operations and commercial 
prospects could be materially harmed.
Changes to patent laws in the United States and foreign jurisdictions could significantly diminish the value of 
patents in general, thereby impairing our ability to protect our technology, products and product candidates.
Changes in either the patent laws or interpretation of patent laws in the United States by the United States Congress, 
the federal courts, or the USPTO, including patent reform legislation such as the Leahy-Smith America Invents Act, 
or the Leahy-Smith Act, or similar changes in other jurisdictions whether by governments, courts or regulators, 
could increase the uncertainties and costs surrounding the prosecution of our owned or in-licensed patent 
applications and the enforcement or defense of our issued patent rights. For example, the Leahy-Smith Act includes 
a number of significant changes to United States patent law. These changes include provisions that affect the way 
patent applications are prosecuted, redefine prior art, provide more efficient and cost-effective avenues for 
competitors to challenge the validity of patents, and enable third-party submission of prior art to the USPTO during 
patent prosecution and additional procedures to attack the validity of a patent at USPTO administered post-grant 
proceedings, including post-grant review, inter partes review and derivation proceedings. Assuming that other 
statutory requirements for patentability are met, prior to March 2013, in the United States, the first to invent the 
claimed invention was entitled to the patent, while outside the United States, the first to file a patent application was 
entitled to the patent. After March 2013, under the Leahy-Smith Act, the United States transitioned to a first inventor 
to file system in which, assuming that the other statutory requirements for patentability are met, the first inventor to 
file a patent application will be entitled to the patent on an invention regardless of whether a third party was the first 
to invent the claimed invention. Accordingly, changes in either the patent laws or interpretation of patent laws in the 
United States or in foreign jurisdictions and their implementation could increase the uncertainties and costs 
surrounding the prosecution of our owned and/or in-licensed patent applications and the enforcement or defense of 
our issued patent rights, which could have a material adverse effect on our business and financial condition. 
We may become involved in lawsuits or other legal proceedings to protect or enforce our patent or other 
intellectual property rights, which could be expensive, time consuming and unsuccessful. 
Competitors may infringe, misappropriate or otherwise violate our patent or other intellectual property rights. As a 
result, we may need to file infringement, misappropriation or other intellectual property claims, which can be 
expensive and time consuming. Any claims we assert against perceived infringers could provoke these parties to 
assert counterclaims against us alleging that we infringe, misappropriate or otherwise violate their intellectual 
property rights. Such parties could also counterclaim that the patent rights we have asserted are invalid or 
unenforceable. In patent litigation in the United States, defendant counterclaims alleging invalidity or 
unenforceability are commonplace. Grounds for a validity challenge could be an alleged failure to meet any of 
several statutory requirements, including lack of novelty, obviousness or non-enablement. Grounds for an 
unenforceability assertion could be an allegation that someone connected with prosecution of the patent withheld 
relevant information, or made a misleading statement, during prosecution. Moreover, third parties may institute such 
claims before administrative bodies in the United States or abroad, and within or outside of the context of litigation. 
Such mechanisms include re-examination, post-grant review, inter partes review, interference proceedings, 
derivation proceedings and equivalent proceedings in foreign jurisdictions (e.g., opposition proceedings).
An adverse result in any such proceeding could put one or more of our patent rights at risk of being invalidated or 
interpreted narrowly, and could put one or more of our owned and/or in-licensed patent applications at risk of being 
found unpatentable. Any of the foregoing could limit our ability to limit our competitors’ ability to develop and 
commercialize competing technologies and products and could have a material adverse impact on our business, 
financial condition, results of operations and prospects. 
We may need to license certain intellectual property from third parties, and such licenses may not be available or 
may not be available on commercially reasonable terms. 
A third party may hold intellectual property rights, including patent rights, that are important or necessary to the 
development of our technology or product candidates or commercialization of our technology or products. It may be 
necessary for us to use the patented or proprietary technology of third parties to develop our technology or product 
candidates or commercialize our technology or products, in which case we may be required to obtain a license from 

68
these third parties. Such licenses may not be available on commercially reasonable terms, or at all, or may only be 
available on a non-exclusive basis, any of which could have a material adverse impact on our business, financial 
condition, results of operations and prospects.
Third parties may initiate legal proceedings alleging that we are infringing, misappropriating or otherwise 
violating their intellectual property rights, the outcome of which would be uncertain and could have a material 
adverse effect on the success of our business. 
Our commercial success depends upon our ability, and the ability of our collaborators, to develop, manufacture, 
market and sell our current and future products and use our proprietary technology without infringing, 
misappropriating or otherwise violating the proprietary rights of third parties. There is considerable intellectual 
property litigation in the biotechnology and pharmaceutical industries. We may become party to, or threatened with, 
litigation or administrative proceedings regarding intellectual property rights with respect to our technology, 
products and product candidates, including interference proceedings, post grant review, inter partes review and 
derivation proceedings before the USPTO and similar proceedings in foreign jurisdictions such as oppositions 
before the European Patent Office. 
Third parties may assert infringement claims against us based on existing patents or patents that may be granted in 
the future, regardless of merit. For example, with respect to tazemetostat, we are aware of a U.S. patent held by a 
third party, which could be construed to cover the use of tazemetostat in certain clinical indications. We have 
preemptively requested inter partes review at the USPTO challenging the validity of that patent. In the event that an 
owner of this patent were to bring an infringement action against us, we believe we have defenses that we could 
assert in such event, and additionally in the USPTO, including the invalidity of the relevant claims of such patents. 
However, we may not be successful in asserting these defenses, including proving invalidity, and could be found to 
infringe this third-party patent.
We may not be aware of all intellectual property rights potentially relating to our technology, products and product 
candidates and their potential uses. Thus, we do not know with certainty that our technology, products and product 
candidates or our development and commercialization thereof, do not and will not infringe, misappropriate or 
otherwise violate any third party’s intellectual property.
Even if we believe that third party intellectual property claims are without merit, there is no assurance that a court or 
other judicial or regulatory body would find in our favor on questions of misappropriation, infringement, validity, 
enforceability or priority. A court of competent jurisdiction or other applicable regulatory body could disregard any 
claims that we make and hold that third-party patents are valid, enforceable and infringed. In order to successfully 
challenge the validity of any U.S. patent in federal court, we would need to overcome a presumption of validity. As 
this burden is a high one requiring us to present clear and convincing evidence as to the invalidity of any such U.S. 
patent claim, there is no assurance that a court of competent jurisdiction would invalidate the claims of any such 
U.S. patent. 
If we are found to infringe a third party’s intellectual property rights, we could be required to obtain a license from 
such third party to continue developing, manufacturing and marketing our technology, products and product 
candidates. However, we may not be able to obtain any required license on commercially reasonable terms or at all. 
Even if we were able to obtain a license, it could be non-exclusive, thereby giving our competitors access to the 
same technologies licensed to us and could require us to make substantial licensing and/or royalty payments. We 
could be forced, including by court order, to cease developing, manufacturing and/or commercializing the infringing 
technology, product candidates or products. In addition, we could be found liable for significant monetary damages, 
including treble damages and attorneys’ fees if we are found to have willfully infringed a patent or other intellectual 
property right and could be forced to indemnify our customers or collaborators. A finding of infringement could 
prevent us from commercializing our technology, product candidates or products and/or could force us to cease 
some of our business operations, which could materially harm our business. Additionally, we could be forced to 
redesign our products or product candidates, seek new regulatory approvals or indemnify third parties pursuant to 
contractual agreements. Claims that we have misappropriated the confidential information or trade secrets of third 
parties could have a similar negative impact on our business, financial condition, results of operations and prospects. 

69
Obtaining and maintaining patent protection depends on compliance with various procedural, document 
submission, fee payment and other requirements imposed by governmental patent agencies, and our patent 
protection could be reduced or eliminated for non-compliance with these requirements. 
Periodic maintenance, renewal and annuity fees and various other governmental fees on any issued patent and 
pending patent application must be paid to the USPTO and foreign patent agencies in several stages or annually over 
the lifetime of our owned and/or in-licensed patents and patent applications. The USPTO and various foreign 
governmental patent agencies require compliance with a number of procedural, documentary, fee payment and other 
similar provisions during the patent application process. In certain circumstances, we rely on our licensing partners 
to pay these fees to, or comply with the procedural and documentary rules of, the relevant patent agency. With 
respect to our patent rights, we employ reputable law firms and other professionals to help us comply, and we rely 
on an annuity service to remind us of the due dates and to make payment after we instruct them to do so. Non-
compliance events that could result in abandonment or lapse of a patent or patent application include, but are not 
limited to, failure to respond to official actions within prescribed time limits, non-payment of fees and failure to 
properly legalize and submit formal documents. In many cases, an inadvertent lapse can be cured by payment of a 
late fee or by other means in accordance with the applicable rules, however the ability to cure may not be possible in 
some cases or may be subject to certain deadlines or other restrictions that may not be practicable to satisfy. While 
to date we have not experienced any material abandonment, lapse or loss of patent rights that was not able to be 
cured, there could be situations in which non-compliance could result in material abandonment or lapse of the patent 
or patent application, resulting in partial or complete loss of patent rights in the relevant jurisdiction. If we or our 
licensors fail to maintain the patents and patent applications covering our technology, products or product 
candidates, potential competitors might be able to enter the market with similar or identical technology, products or 
product candidates, which could have a material adverse effect on our business, financial condition, results of 
operations and prospects.
If we fail to comply with our obligations in our intellectual property licenses and funding arrangements with 
third parties, we could lose rights that are important to our business. 
We are party to license and research agreements that impose, and we may enter into additional licensing and funding 
arrangements with third parties that may impose, on us diligence, development and commercialization timelines, 
milestone payment, royalty, insurance and other obligations. Under our existing licensing and funding agreements, 
we are obligated to pay royalties on net product sales of products or related technologies to the extent they are 
covered by the agreements. If we fail to comply with our obligations under current or future license and funding 
agreements, our counterparties may have the right to terminate these agreements, in which event we might not be 
able to develop, manufacture or commercialize any product that is covered by these agreements or may face other 
penalties under the agreements. Such an occurrence could materially adversely affect the value of the products or 
product candidates being developed under any such agreement. Termination of these agreements or reduction or 
elimination of our rights under these agreements may result in our having to negotiate new or reinstated agreements 
with less favorable terms, or cause us to lose our rights under these agreements, including our rights to important 
intellectual property or technology, which could have a material adverse effect on our business, financial condition, 
results of operations and prospects.
We may be subject to claims by third parties asserting that our employees, consultants, contractors or we have 
wrongfully used or disclosed alleged trade secrets of their current or former employers or claims asserting that 
we have misappropriated their intellectual property, or claiming ownership of what we regard as our own 
intellectual property. 
Many of our employees, consultants and contractors were previously employed at universities or other 
biotechnology or pharmaceutical companies, including our competitors or potential competitors. Although we try to 
ensure that our employees, consultants and contractors do not use the proprietary information or know-how of others 
in their work for us, we may be subject to claims that these employees, consultants and contractors or we have used 
or disclosed intellectual property, including trade secrets or other proprietary information, of any such employee’s 
former employer. Litigation may be necessary to defend against these claims. 
In addition, while it is our policy to require our employees, consultants and contractors who may be involved in the 
development of intellectual property to execute agreements assigning such intellectual property to us, we may be 
unsuccessful in executing such an agreement with each party who in fact develops or has developed intellectual 
property that we regard as our own. Our and their assignment agreements may not be self-executing or may be 

70
breached, and we may be forced to bring claims against third parties, or defend claims they may bring against us, to 
determine the ownership of what we regard as our intellectual property. 
If we fail in prosecuting or defending any such claims, in addition to paying monetary damages, we may lose 
valuable intellectual property rights or personnel, which could have a material adverse effect on our competitive 
business position and prospects. Such intellectual property rights could be awarded to a third party, and we could be 
required to obtain a license from such third party to develop and/or commercialize our technology, product 
candidates, and/or products, which license may not be available on commercially reasonable terms, or at all, or such 
license may be non-exclusive. Even if we are successful in prosecuting or defending against such claims, litigation 
could result in substantial costs and be a distraction to our management and employees. 
Intellectual property litigation or other legal proceedings relating to intellectual property could cause us to spend 
substantial resources and distract our personnel from their normal responsibilities. 
Even if resolved in our favor, litigation or other legal proceedings relating to intellectual property claims may cause 
us to incur significant expenses, and could distract our technical and management personnel from their normal 
responsibilities. In addition, there could be public announcements of the results of hearings, motions or other interim 
proceedings or developments and if securities analysts or investors perceive these results to be negative, it could 
have a substantial adverse effect on the price of our common stock. Such litigation or proceedings could 
substantially increase our operating losses and reduce the resources available for development activities or any 
future sales, marketing or distribution activities. We may not have sufficient financial or other resources to conduct 
such litigation or proceedings adequately. Some of our competitors may be able to sustain the costs of such litigation 
or proceedings more effectively than we can because of their greater financial resources and may also have an 
advantage in such proceedings due to their more mature and developed intellectual property portfolios. Uncertainties 
resulting from the initiation and continuation of patent or other intellectual property litigation or other proceedings 
could compromise our ability to compete in the marketplace. 
If we are unable to protect the confidentiality of our trade secrets, our business and competitive position would be 
harmed. 
In addition to seeking patents for some of our technology, products and product candidates, we also rely on trade 
secrets, including unpatented know-how, technology and other proprietary information, to maintain our competitive 
position. We seek to protect these trade secrets and other proprietary technology, in part, by entering into non-
disclosure and confidentiality agreements with parties who have access to them, such as our employees, corporate 
collaborators, outside scientific collaborators, contract research organizations, contract manufacturers, consultants, 
advisors and other third parties. We also enter into confidentiality and invention or patent assignment agreements 
with our employees, consultants and contractors. Despite these efforts, any of these parties may breach the 
agreements and disclose our proprietary information, including our trade secrets, and we may not be able to obtain 
adequate remedies for such breaches. Enforcing a claim that a party illegally disclosed or misappropriated a trade 
secret is difficult, expensive and time-consuming, and the outcome is unpredictable. In addition, some courts inside 
and outside of the United States are less willing or unwilling to protect trade secrets. If any of our trade secrets were 
to be lawfully obtained or independently developed by a competitor, we would have no right to prevent them, or 
those to whom they communicate it, from using that technology or information to compete with us. If any of our 
trade secrets were to be disclosed to or independently developed by a competitor, our competitive position could be 
harmed. 
Risks Related to Regulatory Approval of Our Product Candidates and Other Legal Compliance Matters 
The marketing approval process is expensive, time-consuming and uncertain and may prevent us from obtaining 
approvals for the commercialization of some or all of our product candidates. If we are not able to obtain, or if 
there are delays in obtaining, required regulatory approvals, we will not be able to commercialize tazemetostat for 
other indications or any other of our product candidates that we develop, and our ability to generate revenue will 
be materially impaired. 
Our product and product candidates, including tazemetostat, and the activities associated with their development and 
commercialization, including their design, testing, manufacture, safety, efficacy, recordkeeping, labeling, storage, 

71
approval, advertising, promotion, sale and distribution, export and import are subject to comprehensive regulation 
by the FDA and other regulatory agencies in the United States and by the EMA and similar regulatory authorities 
outside of the United States. 
Failure to obtain marketing approval for tazemetostat for any potential indication or of any other product candidate 
will prevent us from commercializing tazemetostat for that indication or the product candidate. We have only 
limited experience in filing and supporting the applications necessary to gain marketing approvals and rely on third-
party clinical research organizations to assist us in this process. Securing marketing approval requires the 
submission of extensive preclinical, clinical and manufacturing data and supporting information to regulatory 
authorities for each therapeutic indication to establish the product candidate’s safety, efficacy and quality. Securing 
marketing approval also requires the submission of information about the product manufacturing process to, and 
inspection of manufacturing facilities by, the regulatory authorities. Our product candidates for which we seek 
approval may not be effective, may be only moderately effective or may prove to have undesirable or unintended 
side effects, toxicities or other characteristics that may preclude our obtaining marketing approval or prevent or limit 
commercial use. New cancer drugs frequently are indicated only for patient populations that have not responded to 
an existing therapy or have relapsed. 
The process of obtaining marketing approvals, both in the United States and abroad, is expensive, may take many 
years if additional clinical trials are required, if approval is obtained at all, and can vary substantially based upon a 
variety of factors, including the type, complexity and novelty of the product candidates involved. Changes in 
marketing approval policies during the development period, changes in or the enactment of additional statutes or 
regulations, or changes in regulatory review for each submitted product application, may cause delays in the 
approval or rejection of an application. Regulatory authorities have substantial discretion in the approval process and 
may refuse to accept any application or may decide that our data is insufficient for approval and require additional 
preclinical, clinical or other studies, or additional manufacturing data. In addition, varying interpretations of the data 
obtained from preclinical and clinical testing could delay, limit or prevent marketing approval of a product candidate 
on an accelerated basis or at all. Any marketing approval we ultimately obtain may be limited or subject to 
restrictions or post-approval commitments that render the approved product not commercially viable.
We received accelerated approval of TAZVERIK in patients with ES and in patients with relapsed or refractory FL. 
In order to obtain accelerated approval for future indications in tazemetostat or any other product candidate, we must 
demonstrate that our product candidate provides meaningful therapeutic benefit over existing treatments. In addition, 
as a condition of accelerated approval of TAZVERIK in ES and FL, continued approval for these indications is 
contingent upon verification and description of clinical benefit in post-marketing confirmatory trials to verify and 
describe the anticipated effect on irreversible morbidity or mortality or other clinical benefit, and if the studies are 
unsuccessful for a given indication, TAZVERIK in ES or FL may be subject to withdrawal procedures. 
Additionally, the FDA and comparable foreign regulatory agencies may have slower response times or be under-
resourced to continue to monitor our future applications for accelerated approval or our ongoing clinical trials due to 
the COVID-19 pandemic and, as a result, review, inspection, and other timelines may be materially delayed. It is 
unknown how long these disruptions could continue, were they to occur. Any elongation or de-prioritization of our 
clinical trials or delay in regulatory review resulting from such disruptions could materially affect the development 
and study of our product candidates.
We may not be able to obtain, or may be delayed in obtaining, orphan drug exclusivity for our product candidates 
and, even if we do, that exclusivity may not prevent the FDA or the EMA from approving other competing 
products. 
Regulatory authorities in some jurisdictions, including the United States and Europe, may designate drugs for 
relatively small patient populations as orphan drugs. Under the Orphan Drug Act, the FDA may designate a product 
as an orphan drug if it is a drug intended to treat a rare disease or condition, which is generally defined as a patient 
population of fewer than 200,000 individuals annually in the United States. 
We have obtained orphan drug designations in the United States for tazemetostat for the treatment of patients with 
FL, chordoma, malignant rhabdoid tumors, or MRT, soft tissue sarcoma, or STS, and mesothelioma. The orphan 

72
drug designation for the treatment of MRT applies to INI1-negative MRT as well as SMARCA4-negative malignant 
rhabdoid tumor of ovary, or MRTO. We have also obtained orphan drug designations for tazemetostat for the 
treatment of patients with FL, DLBCL and malignant mesothelioma in Europe. 
We have also received orphan drug designation from the FDA for EZM0414 for the treatment of multiple myeloma. 
We may not receive orphan drug designation for tazemetostat or for EZM0414 for other indications, or for any other 
future clinical candidates we may develop. 
We have also obtained marketing exclusivity designations for tazemetostat for the treatment of patients with ES and 
FL. Generally, if a product with an orphan drug designation subsequently receives the first marketing approval for 
the indication for which it has such designation, the product is entitled to a period of marketing exclusivity, which 
precludes the EMA or the FDA from approving another marketing application for the same drug for the same 
indication for that time period. The applicable period is seven years in the United States and ten years in Europe. 
The exclusivity period in Europe can be reduced to six years if a drug no longer meets the criteria for orphan drug 
designation or if the drug is sufficiently profitable so that market exclusivity is no longer justified. Orphan drug 
exclusivity may be lost if the FDA or EMA determines that the request for designation was materially defective or if 
the manufacturer is unable to assure sufficient quantity of the drug to meet the needs of patients with the rare disease 
or condition.  
Even if we obtain orphan drug exclusivity for a product, that exclusivity may not effectively protect the product 
from competition because different drugs can be approved for the same condition. In addition, even after an orphan 
drug is approved, the FDA can subsequently approve the same drug for the same condition if the FDA concludes 
that the later drug is clinically superior in that it is shown to be safer, more effective or makes a major contribution 
to patient care. 
On August 18, 2017, Congress passed the FDA Reauthorization Act of 2017, or FDARA. FDARA, among other 
things, codified the FDA’s pre-existing regulatory interpretation, to require that a drug sponsor demonstrate the 
clinical superiority of an orphan drug that is otherwise the same as a previously approved drug for the same rare 
disease in order to receive orphan drug exclusivity. The new legislation reverses prior precedent holding that the 
Orphan Drug Act unambiguously requires that the FDA recognize the orphan exclusivity period regardless of a 
showing of clinical superiority. Under Omnibus legislation signed by President Trump on December 27, 2020, the 
requirement for a product to show clinical superiority applies to drugs and biologics that received orphan drug 
designation before enactment of FDARA in 2017 but has not yet been approved or licensed by the FDA.
The FDA may further reevaluate the Orphan Drug Act and its regulations and policies. This may be particularly true 
in light of a decision from the Court of Appeals for the 11th Circuit in September 2021 finding that, for the purpose 
of determining the scope of exclusivity, the term “same disease or condition” means the designated “rare disease or 
condition” and could not be interpreted by the FDA to mean the “indication or use.” The court concluded that 
orphan drug exclusivity applies to the entire designated disease or condition rather than the “indication or use”. We 
do not know if, when, or how the FDA may change the orphan drug regulations and policies in the future, and it is 
uncertain how any changes might affect our business. Depending on what changes the FDA may make to its orphan 
drug regulations and policies, our business could be adversely impacted. 
In addition, FDARA amended section 505B “Research into pediatric uses for drugs and biological products” of the 
Federal Food, Drug and Cosmetic Act (21 U.S.C. Section 355c). Previously, drugs that had been granted orphan 
drug designation were exempt from the requirements of the Pediatric Research Equity Act. Under the amended 
section 505B, beginning on August 18, 2020, the submission of a pediatric assessment, waiver or deferral will be 
required for certain molecularly targeted cancer indications with the submission of an NDA application or 
supplement to an NDA application. Under FDARA, products with orphan drug designation that fall under this 
category will no longer be exempt from the pediatric research requirement. In December 2019, the FDA issued draft 
guidance interpreting and implementing these provisions. FL qualifies for an automatic full pediatric waiver by the 
FDA because it rarely or never occurs in pediatric patients. However, our other indications in development or future 
product candidates may require a pediatric assessment, which could result in delays in obtaining orphan drug 
exclusivity and increased costs and delays in obtaining regulatory approval.

73
We may seek certain designations for our product candidates, including Fast Track and Breakthrough Therapy, 
designations, but we might not receive such designations, and even if we do, such designations may not lead to a 
faster development or regulatory review or approval process. 
We may seek certain designations for one or more of our product candidates that could expedite review and 
approval by the FDA. For example, if a drug is intended for the treatment of a serious or life-threatening condition 
and the drug demonstrates the potential to address unmet medical needs for this condition, the drug sponsor may 
apply for FDA Fast Track designation. Drugs that have received Fast Track designation from the FDA are eligible 
for expedited development and priority review, and the opportunity for a rolling review, under certain 
circumstances. 
A breakthrough therapy is defined as a drug that is intended, alone or in combination with one or more other drugs, 
to treat a serious or life-threatening disease or condition, and preliminary clinical evidence indicates that the drug 
may demonstrate substantial improvement over existing therapies on one or more clinically significant endpoints, 
such as substantial treatment effects observed early in clinical development. For drugs and biologics that have been 
designated as breakthrough therapies, interaction and communication between the FDA and the sponsor of the trial 
can help to identify the most efficient path for clinical development while minimizing the number of patients placed 
in ineffective control regimens. Drugs designated as breakthrough therapies by the FDA are also eligible for 
accelerated approval. 
We have received Fast Track designation from the FDA for tazemetostat for patients with relapsed or refractory FL, 
relapsed or refractory DLBCL with EZH2 activating mutations, and metastatic or locally advanced ES who have 
progressed on or following an anthracycline-based treatment regimen. We have also received Fast Track designation 
from the FDA for EZM0414 in adult patients with relapsed or refractory DLBCL. We intend to seek Fast Track 
designation for tazemetostat and EZM0414 for other indications and any other future product candidates as 
appropriate. Our submissions for marketing approval of tazemetostat in ES and FL received expedited development 
and priority review. We may also seek breakthrough therapy designation for tazemetostat, EZM0414 or any future 
product candidate we may develop. 
The FDA has broad discretion whether or not to grant such designations, so even if we believe a particular product 
candidate is eligible for the designation, we cannot assure that the FDA would decide to grant it. Moreover, even if 
we do receive Fast Track or breakthrough therapy designation, we may not experience a faster development process, 
review or approval compared to conventional FDA procedures. We or the FDA may withdraw these designations if 
either party believes that the designation is no longer supported by data from our clinical development program. 
Failure to obtain marketing approval in foreign jurisdictions would prevent our product candidates from being 
marketed in those jurisdictions. 
In order to market and sell TAZVERIK or any other product candidate that we may develop in the European Union, 
or EU, and many other foreign jurisdictions, we or our third-party collaborators must obtain separate marketing 
approvals and comply with numerous and varying regulatory requirements. The approval procedure varies among 
countries and can involve additional testing. The time required to obtain approval may differ substantially from that 
required to obtain FDA approval. The regulatory approval process outside of the United States generally includes all 
of the risks associated with obtaining FDA approval. In addition, in many countries outside of the United States, a 
product must be approved for reimbursement before the product can be approved for sale in that country. We or our 
third-party collaborators may not obtain approvals from regulatory authorities outside of the United States on a 
timely basis, if at all. Approval by the FDA does not ensure approval by regulatory authorities in other countries or 
jurisdictions, and approval by one regulatory authority outside of the United States does not ensure approval by 
regulatory authorities in other countries or jurisdictions or by the FDA. We may not be able to file for marketing 
approvals and may not receive necessary approvals to commercialize our products in any market. 
Additionally, on June 23, 2016, the electorate in the United Kingdom voted in favor of leaving the European Union, 
commonly referred to as Brexit. Following protracted negotiations, the United Kingdom left the European Union on 
January 31, 2020 and a transition period to December 31, 2020, was established to allow the United Kingdom and 
the European Union to negotiate the United Kingdom’s withdrawal. As a result, effective January 1, 2021, the 
United Kingdom is no longer part of the European Single Market and European Union Customs Union. A co-
operation agreement was signed between the United Kingdom and the European Union in December 2020, which 
was applied provisionally beginning in January 1, 2021 and entered into force on May 1, 2021. The agreement 
addresses trade, economic arrangements, law enforcement, judicial cooperation and a governance framework 

74
including procedures for dispute resolution, among other things. As both parties continue to work on the rules for 
implementation, significant political and economic uncertainty remains about how the precise terms of the 
relationship between the parties will differ from the terms before withdrawal. 
Since the regulatory framework for pharmaceutical products in the United Kingdom covering the quality, safety, and 
efficacy of pharmaceutical products, clinical trials, marketing authorization, commercial sales, and distribution of 
pharmaceutical products is derived from European Union directives and regulations, the consequences of Brexit and 
the impact the future regulatory regime that applies to products and the approval of product candidates in the United 
Kingdom remains unclear. As of January 1, 2021, the Medicines and Healthcare products Regulatory Agency, or the 
MHRA, became responsible for supervising medicines and medical devices in Great Britain, comprising England, 
Scotland and Wales under domestic law, whereas Northern Ireland will continue to be subject to European Union 
rules under the Northern Ireland Protocol. The MHRA will rely on the Human Medicines Regulations 2012 (SI 
2012/1916) (as amended), or the HMR, as the basis for regulating medicines. The HMR has incorporated into the 
domestic law of the body of European Union law instruments governing medicinal products that pre-existed prior to 
the United Kingdom’s withdrawal from the European Union. Any delay in obtaining, or an inability to obtain, any 
marketing approvals, as a result of Brexit or otherwise, may force us to restrict or delay efforts to seek regulatory 
approval in the United Kingdom for our product candidates, which could significantly and materially harm our 
business.
We expect that we will be subject to additional risks in commercializing any of our product candidates that receive 
marketing approval outside the United States, including tariffs, trade barriers and regulatory requirements; economic 
weakness, including inflation, or political instability in particular foreign economies and markets; compliance with 
tax, employment, immigration and labor laws for employees living or traveling abroad; foreign currency 
fluctuations, which could result in increased operating expenses and reduced revenue, and other obligations incident 
to doing business in another country; and workforce uncertainty in countries where labor unrest is more common 
than in the United States.
The FDA, EMA or other comparable foreign regulatory authorities could require the clearance or approval of a 
companion diagnostic device as a condition of approval for any product candidate that requires or would 
commercially benefit from such tests. Failure to successfully validate, develop and obtain regulatory clearance or 
approval for companion diagnostics on a timely basis or at all could harm our product development strategy and 
we may not realize the commercial potential of any such product candidate. 
If safe and effective use of any of our other product candidates depends on an in vitro diagnostic, then the FDA 
generally will require approval or clearance of that diagnostic, known as a companion diagnostic, at the same time 
that the FDA approves our product candidates. The process of obtaining or creating such diagnostic is time 
consuming and costly. Companion diagnostics, which provide information that is essential for the safe and effective 
use of a corresponding therapeutic product, are subject to regulation by the FDA, EMA and other comparable 
foreign regulatory authorities as medical devices and require separate regulatory approval from therapeutic approval 
prior to commercialization. The FDA previously has required in vitro companion diagnostics intended to select the 
patients who will respond to a product candidate to obtain pre-market approval, or PMA, simultaneously with 
approval of the therapeutic candidate. The PMA process, including the gathering of preclinical and clinical data and 
the submission and review by the FDA, can take several years or longer. It involves a rigorous pre-market review 
during which the applicant must prepare and provide FDA with reasonable assurance of the device’s safety and 
effectiveness and information about the device and its components regarding, among other things, device design, 
manufacturing, and labeling. After a device is placed on the market, it remains subject to significant regulatory 
requirements, including requirements governing development, testing, manufacturing, distribution, marketing, 
promotion, labeling, import, export, record-keeping, and adverse event reporting.
Given our limited experience in developing and commercializing diagnostics, we do not plan to develop companion 
diagnostics internally and thus will be dependent on the sustained cooperation and effort of third-party collaborators 
in developing and obtaining approval for these companion diagnostics. We may not be able to enter into 
arrangements with a provider to develop a companion diagnostic for use in connection with a registrational trial for 
our product candidates or for commercialization of our product candidates, or do so on commercially reasonable 
terms, which could adversely affect and/or delay the development or commercialization of our product candidates. 
We and our future collaborators may encounter difficulties in developing and obtaining approval for the companion 
diagnostics, including issues relating to selectivity/specificity, analytical validation, reproducibility, or clinical 
validation. Any delay or failure by our collaborators to develop or obtain regulatory approval of the companion 

75
diagnostics could delay or prevent approval of our product candidates. In addition, we, our collaborators or third 
parties may encounter production difficulties that could constrain the supply of the companion diagnostics, and both 
they and we may have difficulties gaining acceptance of the use of the companion diagnostics by physicians. 
We believe that adoption of screening and treatment into clinical practice guidelines is important for payer access, 
reimbursement, utilization in medical practice and commercial success, but both our collaborators and we may have 
difficulty gaining acceptance of the companion diagnostic into clinical practice guidelines. If such companion 
diagnostics fail to gain market acceptance, it would have an adverse effect on our ability to derive revenues from 
sales, if any, of any of our product candidates that are approved for commercial sale. In addition, any companion 
diagnostic collaborator or third party with whom we contract may decide not to commercialize or to discontinue 
selling or manufacturing the companion diagnostic that we anticipate using in connection with development and 
commercialization of our product candidates, or our relationship with such collaborator or third party may otherwise 
terminate. We may not be able to enter into arrangements with another provider to obtain supplies of an alternative 
diagnostic test for use in connection with the development and commercialization of our product candidates or do so 
on commercially reasonable terms, which could adversely affect and/or delay the development or commercialization 
of our product candidates.
Tazemetostat is, and any other product candidate for which we obtain marketing approval could be, subject to 
post-marketing restrictions or withdrawal from the market and we may be subject to substantial penalties if we 
fail to comply with regulatory requirements or if we experience unanticipated problems with our products, when 
and if any of them are approved. 
Tazemetostat and any other product candidate for which we obtain marketing approval, along with the 
manufacturing processes, post-approval clinical data, labeling, advertising and promotional activities for such 
product, will be subject to continual requirements of and review by the FDA and other regulatory authorities. These 
requirements include submissions of safety and other post-marketing information and reports, registration and listing 
requirements, cGMP requirements relating to manufacturing, quality control, quality assurance and corresponding 
maintenance of records and documents, requirements regarding the distribution of samples to physicians and 
recordkeeping. As a condition of accelerated approval, the FDA may require a sponsor to perform post-marketing 
confirmatory studies to verify and describe the predicted effect on irreversible morbidity or mortality or other 
clinical endpoint, and the drug may be subject to accelerated withdrawal procedures. The accelerated approval for 
tazemetostat subjects us to these conditions. Even if marketing approval of a product candidate is granted, the 
approval may be subject to limitations on the indicated uses for which the product may be marketed or to the 
conditions of approval, including the requirement to implement a risk evaluation and mitigation strategy. New 
cancer drugs frequently are indicated only for patient populations that have not responded to an existing therapy or 
have relapsed. If tazemetostat or any other product candidate that we may develop receives marketing approval, the 
accompanying label may limit the approved use of our drug in this way, which could limit sales of the product. 
The FDA may also impose requirements for costly post-marketing studies or clinical trials and surveillance to 
monitor the safety or efficacy of the product for any approved indication. The FDA and other agencies, including the 
Department of Justice, or the DOJ, closely regulate and monitor the post-approval marketing and promotion of drugs 
to ensure they are marketed and distributed only for the approved indications and in accordance with the provisions 
of the approved labeling. The FDA and DOJ impose stringent restrictions on manufacturers’ communications 
regarding off-label use, and if we do not market our products for their approved indications, we may be subject to 
enforcement action for off-label marketing. Violations of the Federal Food, Drug, and Cosmetic Act and other 
statutes, including the False Claims Act, relating to the promotion and advertising of prescription drugs may lead to 
investigations and enforcement actions alleging violations of federal and state health care fraud and abuse laws, as 
well as state consumer protection laws. 
In addition, later discovery of previously unknown adverse events or other problems with our products, 
manufacturers or manufacturing processes, or failure to comply with regulatory requirements, may yield various 
results, including: 

restrictions on such products, manufacturers or manufacturing processes; 

restrictions on the labeling or marketing of a product; 

76

restrictions on product distribution or use; 

requirements to conduct post-marketing studies or clinical trials; 

warning letters or untitled letters; 

withdrawal of the products from the market; 

refusal to approve pending applications or supplements to approved applications that we submit; 

recall of products; 

fines, restitution or disgorgement of profits or revenues; 

suspension or withdrawal of marketing approvals; 

damage to relationships with any potential collaborators; 

unfavorable press coverage and damage to our reputation; 

refusal to permit the import or export of our products; 

product seizure; 

injunctions or the imposition of civil or criminal penalties; or 

litigation involving patients using our products. 
We conduct a substantial portion of our clinical trials in the EU. Non-compliance with EU and UK requirements 
regarding safety monitoring or pharmacovigilance, and with requirements related to the development of products for 
the pediatric population, can also result in significant financial penalties. 
If our drug product candidates or any of our future drug product candidates obtain regulatory approval, 
additional competitors could enter the market with generic versions of such products, which may result in a 
material decline in sales of our competing products. 
Under the Drug Price Competition and Patent Term Restoration Act of 1984, or the Hatch-Waxman Amendments to 
the Federal Food, Drug, and Cosmetic Act, or the FDCA, a company may file an abbreviated new drug application, 
or ANDA, seeking approval of a generic version of an approved innovator product. Under the Hatch-Waxman 
Amendments, a company may also submit an NDA under section 505(b)(2) of the FDCA that references the FDA’s 
prior approval of the innovator product or preclinical studies and/or clinical trials that were not conducted by, or for, 
the applicant and for which the applicant has not obtained a right of reference. A 505(b)(2) NDA product may be for 
a new or improved version of the original innovator product. The Hatch-Waxman Amendments also provide for 
certain periods of regulatory exclusivity, which preclude FDA approval (or in some circumstances, FDA filing and 
review) of an ANDA or 505(b)(2) NDA. 
In addition to the benefits of regulatory exclusivity, an innovator NDA holder may have patents claiming the active 
ingredient, product formulation or an approved use of the drug, which would be listed with the product in the FDA 
publication “Approved Drug Products with Therapeutic Equivalence Evaluations,” known as the Orange Book. If 
there are patents listed in the Orange Book for the applicable, approved innovator product, a generic or 505(b)(2) 
applicant that seeks to market its product before expiration of the patents must include in their applications what is 
known as a “Paragraph IV” certification, challenging the validity or enforceability, or claiming non-infringement, of 
the listed patent or patents. Notice of the certification must be given to the patent owner and NDA holder and if, 
within 45 days of receiving notice, either the patent owner or NDA holder sues for patent infringement, approval of 
the ANDA or 505(b)(2) NDA is stayed for up to 30 months. 
Accordingly, if any of our product candidates that are regulated as drugs are approved, competitors could file 
ANDAs for generic versions of these products or 505(b)(2) NDAs that reference our products. If there are patents 
listed for such drug products in the Orange Book, those ANDAs and 505(b)(2) NDAs would be required to include a 
certification as to each listed patent indicating whether the ANDA applicant does or does not intend to challenge the 
patent. We cannot predict which, if any, patents in our current portfolio or patents we may obtain in the future will 

77
be eligible for listing in the Orange Book, how any generic competitor would address such patents, whether we 
would sue on any such patents or the outcome of any such suit. 
We may not be successful in securing or maintaining proprietary patent protection for products and technologies we 
develop or license, despite expending a significant amount of resources that could have been focused on other areas 
of our business. Moreover, if any of our owned or in-licensed patents that are listed in the Orange Book are 
successfully challenged by way of a Paragraph IV certification and subsequent litigation, the affected product could 
immediately face generic competition and its sales would likely decline rapidly and materially.
Enacted legislation and future legislation may increase the difficulty and cost for us to obtain marketing approval 
of and commercialize our product candidates and affect the prices we may obtain. 
In the United States and some foreign jurisdictions, there have been a number of legislative and regulatory changes 
and proposed changes regarding the healthcare system that could prevent or delay marketing approval of our product 
candidates, restrict or regulate post-approval activities and affect our ability to profitably sell any product candidates 
for which we obtain marketing approval. In the United States, the Medicare Prescription Drug, Improvement, and 
Modernization Act of 2003, or the MMA, changed the way Medicare covers and pays for pharmaceutical products. 
The legislation expanded Medicare coverage for drug purchases by the elderly and introduced a new reimbursement 
methodology based on average sales prices for physician-administered drugs. In addition, this legislation provided 
authority for limiting the number of drugs that will be covered in any therapeutic class. Cost reduction initiatives and 
other provisions of this legislation could decrease the coverage and price that we receive for any approved products. 
While the MMA applies only to drug benefits for Medicare beneficiaries, private payors often follow Medicare 
coverage policy and payment limitations in setting their own reimbursement rates. Therefore, any reduction in 
reimbursement that results from the MMA may result in a similar reduction in payments from private payors. 
In March 2010, the U.S. Congress passed the Patient Protection and Affordable Care Act, as amended by the Health 
Care and Education Affordability Reconciliation Act, or collectively, the PPACA, a sweeping law which included 
changes to the coverage and reimbursement of drug products under government healthcare programs. Among the 
provisions of the PPACA of importance to tazemetostat and to our potential product candidates are the following: 

an annual, nondeductible fee on any entity that manufactures or imports specified branded prescription 
drugs and biologic agents; 

an increase in the statutory minimum rebates a manufacturer must pay under the Medicaid Drug Rebate 
Program; 

expansion of healthcare fraud and abuse laws, including the False Claims Act and the Anti-Kickback 
Statute, new government investigative powers, and enhanced penalties for noncompliance; 

a Medicare Part D coverage gap discount program, in which manufacturers must agree to offer 50% 
point-of-sale discounts off negotiated prices; 

extension of manufacturers’ Medicaid rebate liability; 

expansion of eligibility criteria for Medicaid programs; 

expansion of the entities eligible for discounts under the Public Health Service pharmaceutical pricing 
program; 

requirements to report financial arrangements with physicians and teaching hospitals; 

a requirement to annually report drug samples that manufacturers and distributors provide to physicians; 
and 

a Patient-Centered Outcomes Research Institute to oversee, identify priorities in, and conduct 
comparative clinical effectiveness research, along with funding for such research. 
In addition, other legislative changes have been proposed and adopted since the ACA was enacted. In August 2011, 
the Budget Control Act of 2011, among other things, created measures for spending reductions by Congress. A Joint 

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Select Committee on Deficit Reduction, tasked with recommending a targeted deficit reduction of at least $1.2 
trillion for the years 2013 through 2021, was unable to reach required goals, thereby triggering the legislation’s 
automatic reduction to several government programs. These changes included aggregate reductions to Medicare 
payments to providers of up to 2% per fiscal year, which went into effect in April 2013 and will remain in effect 
through 2031 under the Coronavirus Aid, Relief, and Economic Security Act, or the CARES Act. Pursuant to 
subsequent legislation, however, these Medicare sequester reductions have been suspended through the end of 
March 2022. From April 2022 through June 2022 a 1% sequester cut will be in effect, with the full 2% cut resuming 
thereafter. The American Taxpayer Relief Act of 2012, among other things, reduced Medicare payments to several 
providers and increased the statute of limitations period for the government to recover overpayments to providers 
from three to five years. These laws may result in additional reductions in Medicare and other healthcare funding 
and otherwise affect the prices we may obtain for any of our products or product candidates for which we may 
obtain regulatory approval or the frequency with which any such product is prescribed or used. 
Since enactment of the ACA, there have been and continue to be, numerous legal challenges and Congressional 
actions to repeal and replace provisions of the law. For example, with enactment of the Tax Cuts for Jobs Act, or 
TCJA, in 2017, Congress repealed the “individual mandate.” The repeal of this provision, which requires most 
Americans to carry a minimal level of health insurance, became effective in 2019. Further, on December 14, 2018, a 
U.S. District Court judge in the Northern District of Texas ruled that the individual mandate portion of the ACA is 
an essential and inseverable feature of the ACA and therefore because the mandate was repealed as part of the 
TCJA, the remaining provisions of the ACA are invalid as well. The U.S. Supreme Court heard this case on 
November 10, 2020 and on June 17, 2021, dismissed this action after finding that the plaintiffs do not have standing 
to challenge the constitutionality of the ACA. Litigation and legislation over the ACA are likely to continue, with 
unpredictable and uncertain results.
The Trump Administration also took executive actions to undermine or delay implementation of the ACA, including 
directing federal agencies with authorities and responsibilities under the ACA to waive, defer, grant exemptions 
from or delay the implementation of any provision of the ACA that would impose a fiscal or regulatory burden on 
states, individuals, healthcare providers, health insurers or manufacturers of pharmaceuticals or medical devices. On 
January 28, 2021, however, President Biden revoked those Orders and issued a new Executive Order which directs 
federal agencies to reconsider rules and other policies that limit Americans’ access to health care and consider 
actions that will protect and strengthen that access. Under this Order, federal agencies are directed to re-examine: 
policies that undermine protections for people with pre-existing conditions, including complications related to 
COVID-19; demonstrations and waivers under Medicaid and the ACA that may reduce coverage or undermine the 
programs, including work requirements; policies that undermine the Health Insurance Marketplace or other markets 
for health insurance; policies that make it more difficult to enroll in Medicaid and the ACA; and policies that reduce 
affordability of coverage or financial assistance, including for dependents.
We expect that these healthcare reforms, as well as other healthcare reform measures that may be adopted in the 
future, may result in additional reductions in Medicare and other healthcare funding, more rigorous coverage 
criteria, new payment methodologies and additional downward pressure on the price that we receive for any 
approved product and/or the level of reimbursement physicians receive for administering any approved product we 
might bring to market. Reductions in reimbursement levels may negatively impact the prices we receive or the 
frequency with which our products are prescribed or administered. Any reduction in reimbursement from Medicare 
or other government programs may result in a similar reduction in payments from private payors. Accordingly, such 
reforms, if enacted, could have an adverse effect on anticipated revenue from any product or product candidate that 
we may successfully develop and for which we may obtain marketing approval and may affect our overall financial 
condition and ability to develop or commercialize any product or product candidate.
Current and future legislative efforts may limit the prices for our products, if and when they are licensed for 
marketing, and that could materially impact our ability to generate revenues.
The prices of prescription pharmaceuticals have also been the subject of considerable discussion in the United 
States. There have been several recent U.S. congressional inquiries, as well as proposed and enacted state and 
federal legislation designed to, among other things, bring more transparency to pharmaceutical pricing, review the 
relationship between pricing and manufacturer patient programs, and reduce the costs of pharmaceuticals under 

79
Medicare and Medicaid. In 2020, President Trump issued several executive orders intended to lower the costs of 
prescription products and certain provisions in these orders have been incorporated into regulations. These 
regulations include an interim final rule implementing a most favored nation model for prices that would tie 
Medicare Part B payments for certain physician-administered pharmaceuticals to the lowest price paid in other 
economically advanced countries, effective January 1, 2021. That rule, however, has been subject to a nationwide 
preliminary injunction and, on December 29, 2021, CMS issued a final rule to rescind it. With issuance of this rule, 
CMS stated that it will explore all options to incorporate value into payments for Medicare Part B pharmaceuticals 
and improve beneficiaries' access to evidence-based care.
In addition, in October 2020, HHS and the FDA published a final rule allowing states and other entities to develop a 
Section 804 Importation Program, or SIP, to import certain prescription drugs from Canada into the United States. 
The final rule is currently the subject of ongoing litigation, but at least six states (Vermont, Colorado, Florida, 
Maine, New Mexico, and New Hampshire) have passed laws allowing for the importation of drugs from Canada 
with the intent of developing SIPs for review and approval by the FDA. Further, on November 20, 2020, HHS 
finalized a regulation removing safe harbor protection for price reductions from pharmaceutical manufacturers to 
plan sponsors under Part D, either directly or through pharmacy benefit managers, unless the price reduction is 
required by law. The implementation of the rule has been delayed by the Biden administration from January 1, 2022 
to January 1, 2023 in response to ongoing litigation. The rule also creates a new safe harbor for price reductions 
reflected at the point-of-sale, as well as a new safe harbor for certain fixed fee arrangements between pharmacy 
benefit managers and manufacturers, the implementation of which have also been delayed by the Biden 
administration until January 1, 2023.
On July 9, 2021, President Biden signed Executive Order 14063, which focuses on, among other things, the price of 
pharmaceuticals. The Order directs the Department of Health and Human Services, or HHS, to create a plan within 
45 days to combat “excessive pricing of prescription pharmaceuticals and enhance domestic pharmaceutical supply 
chains, to reduce the prices paid by the federal government for such pharmaceuticals, and to address the recurrent 
problem of price gouging.” On September 9, 2021, HHS released its plan to reduce pharmaceutical prices. The key 
features of that plan are to: (a) make pharmaceutical prices more affordable and equitable for all consumers and 
throughout the health care system by supporting pharmaceutical price negotiations with manufacturers; (b) improve 
and promote competition throughout the prescription pharmaceutical industry by supporting market changes that 
strengthen supply chains, promote biosimilars and generic drugs, and increase transparency; and (c) foster scientific 
innovation to promote better healthcare and improve health by supporting public and private research and making 
sure that market incentives promote discovery of valuable and accessible new treatments.
At the state level, individual states are increasingly aggressive in passing legislation and implementing regulations 
designed to control pharmaceutical and biological product pricing, including price or patient reimbursement 
constraints, discounts, restrictions on certain product access and marketing cost disclosure and transparency 
measures, and, in some cases, designed to encourage importation from other countries and bulk purchasing. In 
addition, regional healthcare organizations and individual hospitals are increasingly using bidding procedures to 
determine what pharmaceutical products and which suppliers will be included in their prescription drug and other 
healthcare programs. These measures could reduce the ultimate demand for our products, once approved, or put 
pressure on our product pricing. We expect that additional state and federal healthcare reform measures will be 
adopted in the future, any of which could limit the amounts that federal and state governments will pay for 
healthcare products and services, which could result in reduced demand for our product candidates or additional 
pricing pressures. 
Our relationships with healthcare providers and third-party payors are subject to applicable anti-kickback, fraud 
and abuse and other healthcare laws and regulations, which, in the event of a violation, could expose us to 
criminal sanctions, civil penalties, contractual damages, reputational harm and diminished profits and future 
earnings. 
Healthcare providers and third-party payors play a primary role in the recommendation and prescription of 
TAZVERIK and will play a primary role in the recommendation and prescription of any future product candidates 
for which we obtain marketing approval. Our current and future arrangements with healthcare providers and third-
party payors may expose us to broadly applicable fraud and abuse and other healthcare laws and regulations that 
may constrain the business or financial arrangements and relationships through which we market, sell and distribute 

80
any products for which we obtain marketing approval. Restrictions under applicable federal and state healthcare 
laws and regulations include the following: 

the federal Anti-Kickback Statute prohibits, among other things, persons from knowingly and willfully 
soliciting, offering, receiving or providing remuneration, directly or indirectly, in cash or in kind, to 
induce or reward, or in return for, either the referral of an individual for, or the purchase, order or 
recommendation or arranging of, any good or service, for which payment may be made under a federal 
healthcare program such as Medicare and Medicaid. Several courts have interpreted the statute’s intent 
requirement to mean that if any one purpose of arrangement involving remuneration is to induce 
referrals of a federal healthcare covered business, the statue has been violated. In addition, the PPACA, 
amended the intent requirement of the federal Anti-Kickback Statute such that a person or entity no 
longer needs to have actual knowledge of the statute or specific intent to violate it to have committed a 
violation. The Anti-Kickback Statute is broad and prohibits many arrangements and practices that are 
lawful in businesses outside of the healthcare industry. Penalties for violations of the federal Anti-
Kickback Statute include criminal penalties and civil sanctions such as fines, imprisonment and possible 
exclusion from Medicare, Medicaid and other federal healthcare programs; 

the federal False Claims Act imposes criminal and civil penalties, including through civil whistleblower 
or qui tam actions, against individuals or entities for, among other things, knowingly presenting, or 
causing to be presented, false or fraudulent claims for payment by a federal healthcare program or 
making a false statement or record material to payment of a false claim or avoiding, decreasing or 
concealing an obligation to pay money to the federal government, with potential liability including 
mandatory treble damages and significant per-claim penalties, currently set at a minimum of $11,665 
and a maximum of $23,331 per false claim; 

the federal Health Insurance Portability and Accountability Act of 1996, or HIPAA, imposes criminal 
and civil liability for executing a scheme to defraud any healthcare benefit program or making false 
statements relating to healthcare matters; 

HIPAA, as amended by the Health Information Technology for Economic and Clinical Health Act and 
its implementing regulations, also imposes obligations, including mandatory contractual terms, with 
respect to safeguarding the privacy, security and transmission of individually identifiable health 
information; 

the federal Physician Payments Sunshine Act requires applicable manufacturers of covered drugs to 
report payments and other transfers of value to physicians, other healthcare providers and teaching 
hospitals; and 

analogous state laws and regulations, such as state anti-kickback and false claims laws and transparency 
statutes, may apply to sales or marketing arrangements and claims involving healthcare items or 
services reimbursed by non-governmental third-party payors, including private insurers. 
Some state laws require pharmaceutical companies to comply with the pharmaceutical industry’s voluntary 
compliance guidelines and the relevant compliance guidance promulgated by the federal government and may 
require drug manufacturers to report information related to payments and other transfers of value to physicians and 
other healthcare providers or marketing expenditures.
The provision of benefits or advantages to physicians to induce or encourage the prescription, recommendation, 
endorsement, purchase, supply, order or use of medicinal products is also prohibited in the EU. The provision of 
benefits or advantages to physicians is governed by the national anti-bribery laws of EU Member States, and, in the 
UK, the U.K. Bribery Act 2010. Infringement of these laws could result in substantial fines and imprisonment.
Payments made to physicians in certain EU Member States must be publicly disclosed. Moreover, agreements with 
physicians often must be the subject of prior notification and approval by the physician’s employer, his or her 
competent professional organization and/or the regulatory authorities of the individual EU Member States. These 
requirements are provided in the national laws, industry codes or professional codes of conduct applicable in the EU 
Member States. Failure to comply with these requirements could result in reputational risk, public reprimands, 
administrative penalties, fines or imprisonment.

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In order to comply with these laws, we have implemented a compliance program to actively identify, prevent and 
mitigate risk through the implementation of compliance policies and systems and by promoting a culture of 
compliance. Although we take our obligation to maintain our compliance with these various laws and regulations 
seriously and our compliance program is designed to prevent the violation of these laws and regulations, we cannot 
guarantee that our compliance program will be sufficient or effective, that we will be able to integrate the operations 
of acquired businesses into our compliance program on a timely basis, that our employees will comply with our 
policies and that our employees will notify us of any violation of our policies, that we will have the ability to take 
appropriate and timely corrective action in response to any such violation, or that we will make decisions and take 
actions that will necessarily limit or avoid liability for whistleblower claims that individuals, such as employees or 
former employees, may bring against us or that governmental authorities may prosecute against us based on 
information provided by individuals. If we are found to be in violation of any of the laws and regulations described 
above or other applicable federal, state and foreign healthcare laws, we may be subject to penalties, including civil, 
criminal and administrative penalties, damages, fines, disgorgement, contractual damages, reputational harm, 
imprisonment, diminished profits and future earnings, exclusion from government healthcare reimbursement 
programs, additional reporting requirements and oversight if we become subject to a corporate integrity agreement 
or similar agreement to resolve allegations of non-compliance with these laws, and/or the curtailment or 
restructuring of our operations, any of which could have a material adverse effect on our business, results of 
operations and growth prospects. Any action against us for violation of these laws or regulations, even if we 
successfully defend against it, could cause us to incur significant legal expenses and divert our management’s 
attention from the operation of our business. Moreover, achieving and sustaining compliance with applicable 
federal, state and foreign healthcare laws is costly and time-consuming for our management.
Reporting and payment obligations under the Medicaid Drug Rebate Program and other governmental drug 
pricing programs are complex and may involve subjective decisions. Any failure to comply with those obligations 
could subject us to penalties and sanctions. 
As a condition of reimbursement by various federal and state health insurance programs, pharmaceutical companies 
are required to calculate and report certain pricing information to federal and state agencies. The regulations 
governing the calculations, price reporting and payment obligations are complex and subject to interpretation by 
various government and regulatory agencies, as well as the courts. Reasonable assumptions have been made where 
there is lack of regulations or clear guidance and such assumptions involve subjective decisions and estimates. 
Pharmaceutical companies are required to report any revisions to our calculation, price reporting and payment 
obligations previously reported or paid. Such revisions could affect liability to federal and state payers and also 
adversely impact reported financial results of operations in the period of such restatement. 
Uncertainty exists as new laws, regulations, judicial decisions, or new interpretations of existing laws, or regulations 
related to our calculations, price reporting or payments obligations increases the chances of a legal challenge, 
restatement or investigation. If a company becomes subject to investigations, restatements, or other inquiries 
concerning compliance with price reporting laws and regulations, it could be required to pay or be subject to 
additional reimbursements, penalties, sanctions or fines, which could have a material adverse effect on the business, 
financial condition and results of operations. In addition, it is possible that future healthcare reform measures could 
be adopted, which could result in increased pressure on pricing and reimbursement of products and thus have an 
adverse impact on financial position or business operations. 
Further, state Medicaid programs may be slow to invoice pharmaceutical companies for calculated rebates resulting 
in a lag between the time a sale is recorded and the time the rebate is paid. This results in a company having to carry 
a liability on its consolidated balance sheets for the estimate of rebate claims expected for Medicaid patients. If 
actual claims are higher than current estimates, the company’s financial position and results of operations could be 
adversely affected. 
In addition to retroactive rebates and the potential for 340B Program refunds, if a pharmaceutical firm is found to 
have knowingly submitted any false price information related to the Medicaid Drug Rebate Program to the Centers 
for Medicare & Medicaid Services (“CMS”), it may be liable for civil monetary penalties. Such failure could also be 

82
grounds for CMS to terminate the Medicaid drug rebate agreement, pursuant to which companies participate in the 
Medicaid program. In the event that CMS terminates a rebate agreement, federal payments may not be available 
under government programs, including Medicaid or Medicare Part B, for covered outpatient drugs. 
Additionally, if a pharmaceutical company overcharges the government in connection with the FSS program or 
Tricare Retail Pharmacy Program, whether due to a misstated Federal Ceiling Price or otherwise, it is required to 
refund the difference to the government. Failure to make necessary disclosures and/or to identify contract 
overcharges can result in allegations against a company under the FCA and other laws and regulations. Unexpected 
refunds to the government, and responding to a government investigation or enforcement action, would be expensive 
and time-consuming, and could have a material adverse effect on our business, financial condition, results of 
operations and growth prospects. 
Our collaborators are also subject to similar requirements outside of the U.S. and thus the attendant risks and 
uncertainties. If our collaborators suffer material and adverse effects from such risks and uncertainties, our rights 
and benefits for our licensed products could be negatively impacted, which could have a material and adverse 
impact on our revenues. 
Compliance with global privacy and data security requirements could result in additional costs and liabilities to 
us or inhibit our ability to collect and process data globally, and the failure to comply with such requirements 
could subject us to significant fines and penalties, which may have a material adverse effect on our business, 
financial condition or results of operations. 
The regulatory framework for the collection, use, safeguarding, sharing, transfer and other processing of information 
worldwide is rapidly evolving and is likely to remain uncertain for the foreseeable future. Globally, virtually every 
jurisdiction in which we operate has established its own data security and privacy frameworks with which we must 
comply. For example, the collection, use, disclosure, transfer, or other processing of personal data regarding 
individuals in the European Union, including personal health data, is subject to the EU General Data Protection 
Regulation, or the GDPR, which took effect across all member states of the European Economic Area, or EEA, in 
May 2018. The GDPR is wide-ranging in scope and imposes numerous requirements on companies that process 
personal data, including strict rules on the transfer of personal data to countries outside the European Union, 
including the United States. 
As a result, there is increased scrutiny on the extent to which clinical trial sites located in the EEA should apply the 
GPDR to transfers of personal data from such sites to countries that are considered to lack an adequate level of data 
protection, such as the United States. The GDPR also permits data protection authorities to require destruction of 
improperly gathered or used personal information and/or impose substantial fines for violations of the GDPR, which 
can be up to four percent of global revenues or 20 million Euros, whichever is greater, and it also confers a private 
right of action on data subjects and consumer associations to lodge complaints with supervisory authorities, seek 
judicial remedies, and obtain compensation for damages resulting from violations of the GDPR. In addition, the 
GDPR provides that European Union member states may make their own further laws and regulations limiting the 
processing of personal data, including genetic, biometric or health data. 
Similar actions are either in place or under way in the United States. There are a broad variety of data protection 
laws that are applicable to our activities, and a wide range of enforcement agencies at both the state and federal 
levels that can review companies for privacy and data security concerns based on general consumer protection laws. 
The Federal Trade Commission and state Attorneys General all are aggressive in reviewing privacy and data 
security protections for consumers. New laws also are being considered at both the state and federal levels. For 
example, the California Consumer Privacy Act—which went into effect on January 1, 2020—is creating similar 
risks and obligations as those created by GDPR, though the Act does exempt certain information collected as part of 
a clinical trial subject to the Federal Policy for the Protection of Human Subjects (the Common Rule). Many other 
states are considering similar legislation. A broad range of legislative measures also have been introduced at the 
federal level. Accordingly, failure to comply with federal and state laws (both those currently in effect and future 
legislation) regarding privacy and security of personal information could expose us to fines and penalties under such 
laws. There also is the threat of consumer class actions related to these laws and the overall protection of personal 
data. Even if we are not determined to have violated these laws, government investigations into these issues 

83
typically require the expenditure of significant resources and generate negative publicity, which could harm our 
reputation and our business. 
Given the breadth and depth of changes in data protection obligations, preparing for and complying with such 
requirements is rigorous and time intensive and requires significant resources and a review of our technologies, 
systems and practices, as well as those of any third-party collaborators, service providers, contractors or consultants 
that process or transfer personal data collected in the European Union. The GDPR and other changes in laws or 
regulations associated with the enhanced protection of certain types of sensitive data, such as healthcare data or 
other personal information from our clinical trials, could require us to change our business practices and put in place 
additional compliance mechanisms, may interrupt or delay our development, regulatory and commercialization 
activities and increase our cost of doing business, and could lead to government enforcement actions, private 
litigation and significant fines and penalties against us and could have a material adverse effect on our business, 
financial condition or results of operations.
We are subject to U.S. and foreign anti-corruption and anti-money laundering laws with respect to our 
operations and non-compliance with such laws can subject us to criminal and/or civil liability and harm our 
business. 
We are subject to the U.S. Foreign Corrupt Practices Act of 1977, as amended, or the FCPA, the U.S. domestic 
bribery statute contained in 18 U.S.C. § 201, the U.S. Travel Act, the USA PATRIOT Act, and other state and 
national anti-bribery and anti-money laundering laws in countries in which we conduct activities. Anti-corruption 
laws are interpreted broadly and prohibit companies and their employees, agents, third-party intermediaries, joint 
venture partners and collaborators from authorizing, promising, offering, or providing, directly or indirectly, 
improper payments or benefits to recipients in the public or private sector. We may have direct or indirect 
interactions with officials and employees of government agencies or government-affiliated hospitals, universities, 
and other organizations. In addition, we may engage third party intermediaries to coordinate our clinical research 
activities abroad and/or to obtain necessary permits, licenses, and other regulatory approvals. We can be held liable 
for the corrupt or other illegal activities of these third-party intermediaries, our employees, representatives, 
contractors, partners, and agents, even if we do not explicitly authorize or have actual knowledge of such activities. 
We have adopted a Code of Business Conduct and Ethics that mandates compliance with the FCPA and other anti-
corruption laws applicable to our business throughout the world. We cannot ensure, however, that our employees 
and third party intermediaries will comply with this code or such anti-corruption laws. Noncompliance with anti-
corruption and anti-money laundering laws could subject us to whistleblower complaints, investigations, sanctions, 
settlements, prosecution, other enforcement actions, disgorgement of profits, significant fines, damages, other civil 
and criminal penalties or injunctions, suspension and/or debarment from contracting with certain persons, the loss of 
export privileges, reputational harm, adverse media coverage, and other collateral consequences. If any subpoenas, 
investigations, or other enforcement actions are launched, or governmental or other sanctions are imposed, or if we 
do not prevail in any possible civil or criminal litigation, our business, results of operations and financial condition 
could be materially harmed. In addition, responding to any such action will likely result in a materially significant 
diversion of management's attention and resources and significant defense and compliance costs and other 
professional fees. In certain cases, enforcement authorities may even cause us to appoint an independent compliance 
monitor which can result in added costs and administrative burdens. 
If we fail to comply with environmental, health and safety laws and regulations, we could become subject to fines 
or penalties or incur costs that could harm our business. 
We are subject to numerous environmental, health and safety laws and regulations, including those governing 
laboratory procedures and the handling, use, storage, treatment and disposal of hazardous materials and wastes. Our 
operations involve the use of hazardous and flammable materials, including chemicals and biological materials. Our 
operations also produce hazardous waste products. We generally contract with third parties for the disposal of these 
materials and wastes. We cannot eliminate the risk of contamination or injury from these materials. In the event of 
contamination or injury resulting from our use of hazardous materials, we could be held liable for any resulting 
damages, and any liability could exceed our resources. We also could incur significant costs associated with civil or 
criminal fines and penalties for failure to comply with such laws and regulations. 

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Although we maintain workers’ compensation insurance to cover us for costs and expenses we may incur due to 
injuries to our employees resulting from the use of hazardous materials, this insurance may not provide adequate 
coverage against potential liabilities. We do not maintain insurance for environmental liability or toxic tort claims 
that may be asserted against us in connection with our storage or disposal of biological, hazardous or radioactive 
materials. 
In addition, we may incur substantial costs in order to comply with current or future environmental, health and 
safety laws and regulations. These current or future laws and regulations may impair our research, development or 
production efforts. Our failure to comply with these laws and regulations also may result in substantial fines, 
penalties or other sanctions. 
Our internal information systems, or those of any collaborators, contractors, consultants, vendors, business 
partners or other third parties, may fail or suffer security breaches, which could result in a material disruption of 
our product development programs. 
We collect, store and transmit large amounts of confidential information, including personal information and 
information relating to intellectual property, on internal information systems and through the information systems of 
our collaborators, contractors, consultants, vendors, business partners or other third parties. 
Despite the ongoing implementation of security measures, our internal information systems and those of third parties 
are vulnerable to damage from computer viruses, malware, unauthorized access, natural disasters, terrorism, war and 
telecommunication and electrical failures. Such systems are also vulnerable to service interruptions or to security 
breaches from inadvertent or intentional actions by our employees, our collaborators, contractors, consultants, 
vendors, business partners and other third parties, or from cyberattacks by malicious third parties over the Internet or 
through other mechanisms. Cyberattacks are increasing in their frequency, sophistication and intensity, and have 
become increasingly difficult to detect. Cyberattacks could include the deployment of harmful malware, 
ransomware, denial of service attacks, social engineering and other means to affect service reliability and threaten 
the confidentiality, integrity and availability of information. Cyberattacks also could include phishing attempts or e-
mail fraud to cause payments or information to be transmitted to an unintended recipient. Our employees and 
systems have been and likely will continue to be targeted by such cyberattacks.
While we have not experienced any material system failure, accident, cyber-attack or security breach to date, if such 
an event were to occur and cause interruptions in our operations, it could result in a material disruption of our 
development programs, clinical trials and business operations, whether due to a loss of our trade secrets or other 
proprietary information or other similar disruptions, in addition to possibly requiring substantial expenditures of 
resources to remedy. In addition, our remediation efforts may not be successful. For example, the loss of clinical 
trial data from clinical trials could result in delays or termination of our regulatory approval efforts and significantly 
increase our costs to recover or reproduce the data. In addition, as risks with respect to our information systems 
continue to evolve, we will incur additional costs to maintain the security of our information systems and comply 
with evolving laws and regulations pertaining to cybersecurity and related areas. To the extent that any disruption or 
security breach were to result in a loss of, or damage to, our data or applications, or inappropriate disclosure of 
confidential or proprietary information, we could incur liability, including regulatory fines and other losses with 
respect to privacy claims, enrollment in our clinical trials could be negatively affected, our competitive position and 
reputation could be harmed and the further development and commercialization of our product candidates could be 
delayed. While we maintain cybersecurity insurance, our insurance may be insufficient to cover all liabilities 
incurred by these incidents, and any incidents may result in loss of, or increased costs of, our cybersecurity 
insurance.
Risks Related to Employee Matters and Managing Growth 
Our future success depends on our ability to retain key executives and to attract, retain and motivate qualified 
personnel. 
We are highly dependent on the research and development, clinical and business expertise of our executive officers 
as well as the other principal members of our management, scientific and clinical teams. Although we have entered 
into employment letter agreements with our executive officers, each of them may terminate their employment with 

85
us at any time. For instance, since January 1, 2017, we have had multiple executive officers, including among others 
our former Executive Vice President and Chief Financial Officer, our former Chief Business Officer, our former 
President of Research and Chief Scientific Officer, and our former Executive Vice President and Chief Medical 
Officer terminate their employment with us. We do not maintain “key person” insurance for any of our executives or 
other employees. 
Recruiting and retaining qualified scientific, clinical, manufacturing, regulatory, and sales and marketing personnel 
will also be critical to our success. We have conducted two restructurings since June 30, 2021 involving the 
termination of many employees. Given the potential impact on employee morale of, and disruption caused by, the 
restructuring and in light of the increasingly competitive job market for companies such as ours, we may not be able 
to retain our employees. The loss of the services of our executive officers or other key employees could impede the 
achievement of our research, development and commercialization objectives and seriously harm our ability to 
successfully implement our business strategy. Furthermore, replacing executive officers and key employees may be 
difficult and may take an extended period of time because of the limited number of individuals in our industry with 
the breadth of skills and experience required to successfully develop, gain regulatory approval of and commercialize 
products. Competition to hire from this limited pool is intense, and we may be unable to hire, train, retain or 
motivate these key personnel on acceptable terms given the competition among numerous pharmaceutical and 
biotechnology companies, universities and research institutions for similar personnel. In addition, we rely on 
consultants and advisors, including scientific and clinical advisors, to assist us in formulating our research and 
development and commercialization strategy. Our consultants and advisors may be employed by employers other 
than us and may have commitments under consulting or advisory contracts with other entities that may limit their 
availability to us. If we are unable to continue to attract and retain an adequate number of high quality personnel, our 
ability to pursue our growth strategy will be limited.
In the future we may need to expand our development, regulatory, sales, marketing and distribution capabilities.  
If and when we expand such capabilities, we may encounter difficulties in managing our growth, which could 
disrupt our operations. 
In the future we may need to grow the number of employees and the scope of our operations, particularly in the 
areas of drug development, regulatory affairs and, sales, marketing and distribution. If and when we experience such 
growth, we will be required to implement and improve our managerial, operational and financial systems, expand 
our facilities and continue to recruit and train additional qualified personnel. Due to our limited financial resources 
and the limited experience of our management team in managing a company with such growth, if and when we 
determine to grow the number of our employees and the scope of our operations, we may not be able to effectively 
manage the expansion of our operations or recruit and train additional qualified personnel. Any such expansion of 
our operations may lead to significant costs and may divert our management and business development resources. 
Any inability to manage growth could delay the execution of our business plans or disrupt our operations. 
Risks Related to Our Common Stock 
Provisions in our corporate charter documents, under Delaware law and in our collaboration agreements could 
make an acquisition of our company, which may be beneficial to our stockholders, more difficult and may 
prevent attempts by our stockholders to replace or remove our current management. 
Provisions in our certificate of incorporation, our bylaws and our collaboration agreements may discourage, delay or 
prevent a merger, acquisition or other change in control of our company that stockholders may consider favorable, 
including transactions in which stockholders might otherwise receive a premium for their shares. These provisions 
could also limit the price that investors might be willing to pay in the future for shares of our common stock, thereby 
depressing the market price of our common stock. In addition, because our board of directors is responsible for 
appointing the members of our management team, these provisions may frustrate or prevent any attempts by our 
stockholders to replace or remove our current management by making it more difficult for stockholders to replace 
members of our board of directors. Among other things, these provisions: 

establish a classified board of directors such that only one of three classes of directors is elected each 
year; 

allow the authorized number of our directors to be changed only by resolution of our board of directors; 

limit the manner in which stockholders can remove directors from our board of directors; 

86

establish advance notice requirements for stockholder proposals that can be acted on at stockholder 
meetings and nominations to our board of directors; 

require that stockholder actions must be effected at a duly called stockholder meeting and prohibit 
actions by our stockholders by written consent; 

limit who may call stockholder meetings; 

authorize our board of directors to issue preferred stock without stockholder approval, which could be 
used to institute a “poison pill” that would work to dilute the stock ownership of a potential hostile 
acquirer, effectively preventing acquisitions that have not been approved by our board of directors; and 

require the approval of the holders of at least 75% of the votes that all our stockholders would be 
entitled to cast to amend or repeal specified provisions of our certificate of incorporation or bylaws. 
Moreover, because we are incorporated in Delaware, we are governed by the provisions of Section 203 of the 
Delaware General Corporation Law, which prohibits a person who owns in excess of 15% of our outstanding voting 
stock from merging or combining with us for a period of three years after the date of the transaction in which the 
person acquired in excess of 15% of our outstanding voting stock, unless the merger or combination is approved in a 
prescribed manner. 
An active trading market for our common stock may not be sustained. 
Although our common stock is listed on The Nasdaq Global Select Market, an active trading market for our shares 
may not be sustained. If an active market for our common stock does not continue, it may be difficult for our 
stockholders to sell their shares without depressing the market price for the shares or sell their shares at all. Any 
inactive trading market for our common stock may also impair our ability to raise capital to continue to fund our 
operations by selling shares and may impair our ability to acquire other companies or technologies by using our 
shares as consideration. 
The price of our common stock has been and may in the future be volatile and fluctuate substantially. 
Our stock price has been and may in the future be volatile. The stock market in general and the market for smaller 
biopharmaceutical companies in particular have experienced extreme volatility that has often been unrelated to the 
operating performance of particular companies. From January 1, 2019 until February 15, 2022, the sale price of our 
common stock as reported on the Nasdaq Global Select Market ranged from a high of $27.82 to a low of $1.01. The 
market price for our common stock may be influenced by many factors, including: 

revenue related to TAZVERIK;

regulatory developments with respect to tazemetostat;

the success of competitive products or technologies; 

results of clinical trials of our product candidates or those of our competitors; 

regulatory or legal developments in the United States and other countries with respect to our product 
candidates; 

developments or disputes concerning patent applications, issued patents or other proprietary rights; 

the recruitment or departure of key personnel; 

the level of expenses related to any of our products, product candidates or clinical development 
programs; 

the results of our efforts to discover, develop, acquire or in-license additional product candidates or 
products; 

actual or anticipated changes in estimates as to financial results, development timelines or 
recommendations by securities analysts; 

87

variations in our financial results or the financial results of companies that are perceived to be similar to 
us; 

changes in the structure of healthcare payment systems; 

market conditions in the pharmaceutical and biotechnology sectors; 

general economic, industry and market conditions;

disruptions in the financial markets caused by the COVID-19 pandemic; and 

the other factors described in this Risk Factors section. 
We have broad discretion over the use of our cash and cash equivalents and may not use them effectively. 
Subject to certain restrictions in our Amended and Restated Loan Agreement documents or in other third-party 
agreements we may enter into from time to time, our management has broad discretion to use our cash and cash 
equivalents to fund our operations and could spend these funds in ways that do not improve our results of operations 
or enhance the value of our common stock. The failure by our management to apply these funds effectively could 
result in financial losses that could have a material adverse effect on our business, cause the price of our common 
stock to decline, delay the development of our product candidates, or adversely impact the success of our 
commercialization efforts with respect to TAZVERIK. Pending their use to fund operations, we may invest our cash 
and cash equivalents in a manner that does not produce income or that loses value. 
Changes in tax laws or in their implementation or interpretation could adversely affect our business and 
financial condition.
Changes in tax law may adversely affect our business or financial condition. The Tax Cuts and Jobs Act of 2017, or 
the TCJA, as amended by the CARES Act, significantly revised the Internal Revenue Code of 1986, as amended, or 
the Code. The TCJA, among other things, contained significant changes to corporate taxation, including a reduction 
of the corporate tax rate from a top marginal rate of 35% to a flat rate of 21%, the limitation of the tax deduction for 
interest expense to 30% of adjusted taxable income (except for certain small businesses), the limitation of the 
deduction for net operating losses arising in taxable years beginning after December 31, 2017 to 80% of current year 
taxable income and elimination of net operating loss carrybacks for losses arising in taxable years ending after 
December 31, 2017 (though any such net operating losses may be carried forward indefinitely and such net 
operating losses arising in taxable years beginning before January 1, 2021 are generally eligible to be carried back 
up to five years), the imposition of a one-time taxation of offshore earnings at reduced rates regardless of whether 
they are repatriated, the elimination of U.S. tax on foreign earnings (subject to certain important exceptions), the 
allowance of immediate deductions for certain new investments instead of deductions for depreciation expense over 
time, and the modification or repeal of many business deductions and credits. In addition to the CARES Act, as part 
of Congress’ response to the COVID-19 pandemic, economic relief legislation has been enacted in 2020 and 2021 
containing numerous tax provisions. 

88
Regulatory guidance under the TCJA and such additional legislation is and continues to be forthcoming, and such 
guidance could ultimately increase or lessen impact of these laws on our business and financial condition. Also, as a 
result of the changes in the U.S. presidential administration and control of the U.S. Senate in 2021, additional tax 
legislation may be enacted; any such additional legislation could have an impact on us. In addition, it is uncertain if 
and to what extent various states will conform to the TCJA and additional tax legislation.
We incur significant costs as a result of operating as a public company, and our management is required to 
devote substantial time to compliance initiatives and corporate governance practices. 
As a public company, we incur significant legal, accounting and other expenses. The Sarbanes-Oxley Act of 2002, 
the Dodd-Frank Wall Street Reform and Consumer Protection Act, the listing requirements of The Nasdaq Global 
Select Market and other applicable securities rules and regulations impose various requirements on public 
companies, including establishment and maintenance of effective disclosure and financial controls and corporate 
governance practices. Our management and other personnel will need to continue to devote a substantial amount of 
time to these compliance initiatives. 
We cannot predict or estimate the amount of costs we may incur to continue to operate as a public company, nor can 
we predict the timing of such costs. These rules and regulations are often subject to varying interpretations, in many 
cases due to their lack of specificity, and, as a result, their application in practice may evolve over time as new 
guidance is provided by regulatory and governing bodies which could result in continuing uncertainty regarding 
compliance matters and higher costs necessitated by ongoing revisions to disclosure and governance practices. 
Pursuant to Section 404 of the Sarbanes-Oxley Act of 2002, or Section 404, we are required to furnish a report by 
our management on our internal control over financial reporting. We are also required to include an attestation 
report on internal control over financial reporting issued by our independent registered public accounting firm. To 
achieve compliance with Section 404 within the prescribed period, we are engaged in a process to document and 
evaluate our internal control over financial reporting, which is both costly and challenging. In this regard, we have 
and will need to continue to dedicate internal resources, engage outside consultants and adopt a detailed work plan 
to assess and document the adequacy of internal control over financial reporting, continue steps to improve control 
processes as appropriate, validate through testing that controls are functioning as documented and implement a 
continuous reporting and improvement process for internal control over financial reporting. If we or our auditors 
identify one or more material weaknesses, it could result in an adverse reaction in the financial markets due to a loss 
of confidence in the reliability of our financial statements. 
Because we do not anticipate paying any cash dividends on our capital stock in the foreseeable future, capital 
appreciation, if any, will be the sole source of gain for our stockholders. 
We have never declared or paid cash dividends on our capital stock. We currently intend to retain all of our future 
earnings, if any, to finance the growth and development of our business. The terms of our Amended and Restated 
Loan Agreement restrict our ability to pay dividends. In addition, the terms of any future debt agreements may 
preclude us from paying dividends. As a result, capital appreciation, if any, of our common stock will be the sole 
source of gain for our stockholders for the foreseeable future. 
If securities or industry analysts do not continue to publish research or publish inaccurate or unfavorable 
research about our business, our share price and trading volume could decline. 
The trading market for our common stock may be impacted, in part, by the research and reports that securities or 
industry analysts publish about us or our business. There can be no assurance that analysts will cover us, continue to 
cover us or provide favorable coverage. If one or more analysts downgrade our stock or change their opinion of our 
stock, our share price may decline. In addition, if one or more analysts cease coverage of our company or fail to 
regularly publish reports on us, we could lose visibility in the financial markets, which could cause our share price 
or trading volume to decline. 

89
There is no public market for our series A convertible preferred stock.
There is no established public trading market for our series A convertible preferred stock, and we do not expect a 
market to develop. In addition, we do not intend to apply for listing of the series A convertible preferred stock on 
any national securities exchange or other nationally recognized trading system. Without an active market, the 
liquidity of the series A convertible preferred stock will be limited.
General Risk Factors
Our employees, independent contractors, CROs, consultants, commercial partners, vendors and principal 
investigators may engage in misconduct or other improper activities, including non-compliance with regulatory 
standards and requirements.
We are exposed to the risk of fraud or other misconduct by our employees, independent contractors, CROs, 
consultants, commercial partners, vendors and, pertaining to clinical trials, our principal investigators. Misconduct 
by these parties could include intentional failures to comply with FDA regulations or the regulations applicable in 
the European Union and other jurisdictions, provide accurate information to the FDA, the European Commission 
and other regulatory authorities, comply with healthcare fraud and abuse laws and regulations in the United States 
and abroad, report financial information or data accurately, or disclose unauthorized activities to us. In particular, 
sales, marketing and business arrangements in the healthcare industry are subject to extensive laws and regulations 
intended to prevent fraud, misconduct, kickbacks, self-dealing and other abusive practices. These laws and 
regulations restrict or prohibit a wide range of pricing, discounting, marketing and promotion, sales commission, 
customer incentive programs and other business arrangements. 
Such misconduct also could involve the improper use of information obtained in the course of clinical trials or 
interactions with the FDA or other regulatory authorities, which could result in regulatory sanctions and cause 
serious harm to our reputation. We have adopted a code of conduct applicable to all of our employees, but it is not 
always possible to identify and deter misconduct, and the precautions we take to detect and prevent such activity 
may not be effective in controlling unknown or unmanaged risks or losses or in protecting us from government 
investigations or other actions or lawsuits stemming from a failure to comply with these laws or regulations. If any 
such actions are instituted against us, and we are not successful in defending ourselves or asserting our rights, those 
actions could have a significant impact on our business, financial condition, results of operations and prospects, 
including the imposition of significant fines or other sanctions.
Item 1B. Unresolved Staff Comments 
None. 
Item 2. Properties 
Our headquarters are located in Cambridge, Massachusetts, where we occupy approximately 43,066 square feet of 
office and laboratory space. The term of the lease to our Cambridge headquarters expires November 30, 2024. In 
addition, we occupy an additional 33,525 square feet in Cambridge, Massachusetts. The term of this lease ends on 
March 31, 2027, but we have an option to extend the term for one additional five-year period. 
Item 3. Legal Proceedings 
We are not currently a party to any material legal proceedings. 
Item 4. Mine Safety Disclosures 
Not applicable. 

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PART II 
Item 5. Market for Registrant’s Common Equity, Related Stockholder Matters and Issuer Purchases of 
Equity Securities 
Market Information
Our common stock is traded on the Nasdaq Global Select Market under the symbol “EPZM.” Trading of our 
common stock commenced on May 31, 2013, following the completion of our initial public offering. Prior to that 
date, there was no public market for our common stock. 
 
Holders
As of February 15, 2022, there were 12 holders of record of our common stock. This number does not include 
beneficial owners whose shares are held in street name. 
Dividends 
We have never declared or paid cash dividends on our capital stock. We intend to retain all of our future earnings, if 
any, to finance the growth and development of our business. The terms of our Amended and Restated Loan 
Agreement with BPCR Limited Partnership (as transferee of BioPharma Credit Investments V (Master) LP’s interest 
as a lender) and BioPharma Credit PLC, or the Amended and Restated Loan Agreement, restrict our ability to pay 
dividends. We do not intend to pay cash dividends to our stockholders in the foreseeable future. 

91
Stock Performance Graph 
The following graph shows a comparison from December 31, 2016 through December 31, 2021 of the cumulative 
total return on an assumed investment of $100.00 in cash in our common stock, the Nasdaq Composite Index and the 
NASDAQ Biotechnology Index. Such returns are based on historical results and are not intended to suggest future 
performance. Data for the NASDAQ Composite Index and NASDAQ Biotechnology Index assume reinvestment of 
dividends. 
The performance graph in this Item 5 is not deemed to be “soliciting material” or to be “filed” with the SEC for 
purposes of Section 18 of the Securities and Exchange Act of 1934, as amended, or otherwise subject to the 
liabilities under that Section, and shall not be deemed incorporated by reference into any of our filings under the 
Securities Act of 1933 or the Securities Exchange Act of 1934, except to the extent we specifically incorporate it by 
reference into such a filing. 
Item 6. None. 

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Item 7. Management’s Discussion and Analysis of Financial Condition and Results of Operations 
Our management’s discussion and analysis of our financial condition and results of operations are based upon our 
consolidated financial statements included in this Annual Report on Form 10-K, which have been prepared by us in 
accordance with accounting principles generally accepted in the United States, or GAAP, and with Regulation S-X 
promulgated under the Securities Exchange Act of 1934, as amended. This discussion and analysis should be read in 
conjunction with these consolidated financial statements and the notes thereto included elsewhere in this Annual 
Report on Form 10-K. Some of the information contained in this discussion and analysis or set forth elsewhere in 
this Annual Report on Form 10-K, including information with respect to our plans and strategy for our business, 
includes forward-looking statements that involve risks and uncertainties. As a result of many factors, including those 
factors set forth in Part I, Item 1A. Risk Factors of this Annual Report on Form 10-K, our actual results could differ 
materially from the results described in or implied by the forward-looking statements contained in the following 
discussion and analysis. 
Note on the COVID-19 Pandemic
The ongoing COVID-19 pandemic continues to have widespread, evolving, and unpredictable impacts on global 
economies, supply chains, financial markets, business practices and societies. The complex challenges created by 
the COVID-19 pandemic have had an adverse impact on our business, operations, and financial performance, and as 
such we continue to take steps to respond to these challenges and adjust our commercial strategy and operating plans 
accordingly.
We believe that the COVID-19 pandemic has had an adverse impact on sales of TAZVERIK since the June 2020 
FDA approval of TAZVERIK for follicular lymphoma, or FL. Our commercial and medical affairs field teams 
continue to use virtual formats as well as in-person interactions, where possible, to allow us to serve the needs of 
healthcare providers, patients and other stakeholders, However, access to prescribers remains restrictive, and we 
expect these challenges to continue through the first half of 2022.
In response, we have taken steps to adjust our commercial strategy and continue to further refine our commercial 
strategy, recognizing that some of the changes brought about by the COVID-19 pandemic, such as ongoing 
restrictions to access prescribers by traditional sales personnel, will likely persist after the resolution of the 
pandemic. We are evolving our commercial strategies and deployment of resources to address these changes in 
market dynamics as we seek to increase awareness of TAZVERIK in ES and FL.
Although the initiation, enrollment and completion of our ongoing and planned clinical trials have not been 
meaningfully disrupted, we have experienced some delays in clinical trial startup activities due to what we believe to 
be mostly related to COVID-19 related capacity constraints and resulting delays in the packaging and labeling of 
clinical drug supply at a third-party manufacturer. We are aware of the impact that COVID-19 continues to have on 
other clinical trials in our industry and there is a risk of material impact on the conduct of our clinical trials as well. 
We are continuing to work with our clinical trial sites as we seek to ensure study continuity, enable medical 
monitoring, facilitate study procedures and maintain clinical data and records, including the use of local laboratories 
for testing, home delivery of study drug and remote data and records monitoring.
To date, the COVID-19 pandemic has not had a material impact on our commercial supply chain, and we currently 
have a consistent supply of tazemetostat and TAZVERIK that we believe will cover our ongoing clinical 
development as well as the ongoing commercialization for ES and FL. From time to time, however, we have 
experienced some occasional delays in connection with our clinical supply, including delays related to packaging 
and labeling. As a proactive measure, we have taken certain steps to try to reduce the risk to our supply chain, such 
as advancing orders for long-lead items in anticipation of potential future delays or shortages. Because the ongoing 
COVID-19 pandemic could materially adversely impact our suppliers and result in delays or disruptions in our 
current or future supply chain, we are continuing to monitor and manage our supply chain accordingly. 
We are implementing a multi-stage return to office plan, and in October 2021 we opened our facilities to all 
employees who expressed interest in participating in a return-to-office pilot program. In the meantime, many of our 
employees continue to work in a remote operating model. Our laboratory scientists who engage in bench research 
activities now have full access to our laboratories. We are using our pilot program to further evaluate this hybrid 
model and will use that evaluation to formulate how we will move forward. Ultimately, our return to office plan will 
be based primarily on guidance from federal, state and local government authorities, and we expect that some form 
of a hybrid model will continue to exist for us in the future.

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We are closely monitoring the impact of the COVID-19 pandemic and related developments on our business, 
operations and financial performance. We plan to continue to assess the potential duration, scope and severity of the 
COVID-19 pandemic and its impacts on our business, operations and financial performance, and to continue to work 
closely with our third-party vendors, collaborators and other parties in order to seek to continue to advance our 
efforts with respect to the commercialization of TAZVERIK and to continue to advance the development of 
EZM0414 and our pipeline, while making the health and safety of our employees and their families, healthcare 
providers, patients and communities a top priority. Due to the evolving and uncertain global impacts of the COVID-
19 pandemic, however, we cannot precisely determine or quantify the impact that this pandemic has had on our 
business, operations and financial performance to date or the impact that this pandemic will have in 2022 and 
beyond.
Please refer to our risk factors set forth in Part I, Item 1A. Risk Factors of this Annual Report on Form 10-K for the 
year ended December 31, 2021 for further discussion of risks related to the COVID-19 pandemic.
Operating Expense Reductions
In response to the challenges we have continued to face since we commenced the launch of TAZVERIK in FL in 
June 2020, in August 2021, we determined to implement changes to our commercial strategy and organization in an 
effort to accelerate commercial adoption of TAZVERIK in appropriate patients while also pursuing our research and 
broader corporate objectives. 
On August 9, 2021, we announced a cross-functional reduction of our 2021 budgeted headcount by approximately 
20%, which included approximately 11% of our then-current workforce under the cost reduction plan. Affected 
employees were provided separation benefits, including severance payments along with temporary healthcare 
coverage assistance. The severance and termination-related costs were approximately $2.0 million. We recorded 
these costs in the third quarter of 2021 and expect that payments of these costs will be made through August 2022.
In addition to the organizational changes and cross-functional headcount reduction announced in August 2021, on 
March 1, 2022, we announced a further reduction of our operating expenses, including a cross-functional workforce 
reduction of approximately 12% of our current employees. Additionally, we announced a pipeline reprioritization. 
Given the breadth of our current tazemetostat clinical development program, we have discontinued enrollment in our 
Phase 2 study of tazemetostat in combination with rituximab with FL in the third line or later treatment settings 
(SYMPHONY-2, EZH-1401), as well as in our Phase 1/1b basket study evaluating tazemetostat combinations in 
patients with solid tumors (EZH-1301) due to evolving market dynamics and a continued focus on optimizing our 
investments and eliminating potentially overlapping studies. 
As part of these March 2022 headcount reductions and our pipeline reprioritization, we are implementing further 
changes to our commercial strategy, to our medical affairs and clinical development teams and to our broader 
organization. We are focused on accelerating commercial adoption of TAZVERIK in appropriate patients and on 
implementing a broader operational cost reduction plan that will reduce our headcount across different areas of the 
organization and re-prioritize our investment of company resources in important clinical trials and programs, 
including our SYMPHONY-1 (EZH-302), CELLO-1 (EZH-1101), EZH-1501 and SET-101 trials. 
We expect that these actions will allow us to keep the company in a financial position that will enable us to continue 
to achieve important near-term milestones and execute on our long-term strategy. As part of the March 2022 
workforce reduction, affected employees will be offered separation benefits, including severance payments along 
with temporary healthcare coverage assistance. We estimate that the severance and termination-related costs will be 
approximately $2.8 - 3.2 million and expect to record these charges in the first quarter of 2022. We expect that 
payments of these costs will be made through the end of the fourth quarter of 2022.
We plan to continue to implement our broader operational expense reduction effort, and to monitor and seek 
opportunities to further reduce our operating expenses. 
Overview 
We are a commercial-stage biopharmaceutical company that is committed to rewriting treatment for people with 
cancer through the discovery, development, and commercialization of novel epigenetic medicines. We aspire to 
change the standard of care for patients and physicians by developing targeted medicines with fundamentally new 
mechanisms of action directed at specific causes of hematological malignancies and solid tumors. 

94
We have one approved product, TAZVERIK (tazemetostat), which was granted accelerated approval by the U.S. 
Food and Drug Administration, or FDA, in 2020 for epithelioid sarcoma, or ES, and FL. Our focus is on maximizing 
our effectiveness as a commercial organization to achieve adoption of TAZVERIK among as many appropriate 
patients as possible, including in earlier treatment lines and in combination regimens with the data to support this 
expanded use; building on TAZVERIK’s pipeline-in-a-drug potential; and expanding our pipeline and evolving 
oncology portfolio, including with SET-101, our first-in-human Phase 1/1b trial of EZM0414, our novel, first-in-
class, oral SETD2 inhibitor. We are leveraging our drug discovery platform and expertise as a leader in epigenetics, 
as well as our team’s deep experience across clinical development and commercialization to execute on our strategy.
In January 2020, the FDA granted accelerated approval of TAZVERIK (tazemetostat), an oral, first in class, 
selective small molecule inhibitor of the EZH2 histone methyltransferase, or HMT, for the treatment of adult and 
pediatric patients aged 16 years and older with metastatic or locally advanced ES not eligible for complete resection. 
This approval was based on overall response rate and duration of response data shown in the ES cohort of our Phase 
2 trial in patients with INI1-negative tumors. We continue to make TAZVERIK available to eligible patients and 
their physicians in the United States. 
As part of the accelerated approval for ES, continued approval for this indication is contingent upon verification and 
description of clinical benefit in a confirmatory trial. To provide this confirmatory evidence to support a full 
approval of TAZVERIK for this indication, we are conducting a single, randomized, controlled Phase 1b/3 
confirmatory trial in the United States (EZH-301) assessing tazemetostat in combination with doxorubicin compared 
with doxorubicin plus placebo as a front-line treatment for ES. The trial is expected to enroll approximately 152 
patients. We have completed the planned enrollment in the Phase 1b safety run-in portion of the trial and the Phase 3 
efficacy portion of the trial is open for accrual. We reported safety and preliminary activity data from the patients in 
the safety run-in portion of the EZH-301 trial at the American Society of Clinical Oncology (ASCO) Annual 
Meeting in June 2021. 
In June 2020, the FDA approved a supplemental New Drug Application, or sNDA, for TAZVERIK for adult 
patients with relapsed or refractory (R/R) FL whose tumors are positive for an EZH2 mutation as detected by an 
FDA-approved test and who have received at least two prior systemic therapies, and adult patients with relapsed or 
refractory FL who have no satisfactory alternative treatment options. These indications were approved under 
accelerated approval with a priority review, based on overall response rate and duration of response data shown in 
the FL cohorts of our Phase 2 clinical trial in patients with EZH2 mutations and wild-type EZH2. We continue to 
make TAZVERIK available to eligible patients and their physicians in the United States.
As part of the accelerated approval for FL, continued approval for these R/R FL indications is contingent upon 
verification and description of clinical benefit in a confirmatory trial. To provide this confirmatory evidence to 
support a full approval of TAZVERIK for these indications, we are conducting a single global, randomized, adaptive 
Phase 1b/3 confirmatory trial (EZH-302, SYMPHONY-1) assessing the combination of tazemetostat with “R2” 
(lenalidomide and rituximab), an approved chemotherapy-free treatment regimen, compared with R2 plus placebo 
for R/R FL patients in the second-line or later treatment setting. We plan to leverage the confirmatory trial and also 
conduct post-marketing commitments to expand the TAZVERIK label into the second-line treatment setting. 
In December 2021 we presented updated safety and activity data from the Phase 1b safety run-in portion of this 
confirmatory trial at the 2021 American Society of Hematology (ASH) Annual Meeting. We continue to follow the 
40 patients in the Phase 1b safety run-in portion of the trial, and we expect to present follow-up data from the safety 
run-in portion of the trial at a medical conference later in 2022. 
We expect that the Phase 3 portion of the SYMPHONY-1 trial will be a global, randomized and adaptive 
confirmatory trial in 500 patients. Based on the Phase 1b safety run-in results, in December 2021 we submitted a 
protocol amendment to the FDA with 800 mg twice-daily as the recommended tazemetostat dose (RP3D) for the 
Phase 3 portion of the trial. After completing the 30-day voluntary waiting period following submission of the 
protocol amendment for 800 mg RP3D without any objection from the FDA, and as we continue to conduct the 
Phase 1b safety run-in portion of the trial, we have accelerated global start-up activities and are activating as many 
study sites as possible, globally, for the Phase 3 portion of the trial. The primary endpoint for the Phase 3 portion of 
the trial will be based on progression free survival as determined by investigator. Based on discussions with the 
FDA, this portion of the trial will include two interim analyses, the first of which is for futility only and the second 
of which will be conducted for futility, and if 65% of progression free survival events have occurred, the trial will 
also include an efficacy evaluation. In July 2021 China’s Center for Drug Evaluation, or CDE, approved the 
Investigational New Drug Application, or IND, we filed in China for SYMPHONY-1. We are currently screening 

95
patients in the Phase 3 portion of this trial and we expect to enroll the first patient in the Phase 3 portion of this trial 
in the first quarter of 2022.
Through our planned development efforts, our intention is to eventually make TAZVERIK available in all lines of 
treatment for patients with FL. In collaboration with The Lymphoma Study Association, or LYSA, and based on 
clinical activity observed with tazemetostat in combination with R-CHOP (rituximab, cyclophosphamide, 
doxorubicin, vincristine and prednisolone) as a front-line treatment for patients with high risk diffuse large B-cell 
lymphoma, or DLBCL, LYSA is conducting a Phase 1b/2 clinical trial to evaluate this combination as a front-line 
treatment for high-risk patients with FL and DLBCL. Patient enrollment in the Phase 2 portion of this trial is now 
nearly complete with 111 patients out of a target of approximately 122 patients in DLBCL and 61 patients out of a 
target of approximately 62 patients in FL enrolled as of February 23, 2022. We expect that interim results from the 
Phase 2 portion of this trial will be presented at a medical conference in the second half of 2022. We are also 
finalizing plans for investigator-sponsored studies to evaluate tazemetostat in combination with venetoclax or BTK 
inhibitors for the treatment of patients with FL in the third-line or later treatment settings.
We are also developing tazemetostat for the treatment of a broad range of other cancer types in multiple treatment 
settings. Tazemetostat has shown meaningful clinical activity as an investigational monotherapy in multiple cancer 
indications and has been generally well-tolerated across clinical trials to date. We believe tazemetostat is a “pipeline 
in a product” opportunity and plan to explore its potential utility in additional indications and combinations.
There are four areas where we see the greatest potential for tazemetostat, all of which are based on a strong scientific 
hypothesis and are for patients suffering from diseases that would benefit from a new effective and safe treatment 
option, including:

Lymphomas and B-cell malignancies, such as DLBCL, mantle cell lymphoma, or MCL, multiple 
myeloma and others;

Molecularly defined solid tumors, such as chordoma, melanoma, mesothelioma, and tumors harboring 
an EZH2 or SWI/SNF alteration;

PARPi-resistant tumors, such as castration-resistant prostate cancer, small cell lung cancer, and others; 
and 

Immuno-oncology sensitive tumors, such as small cell lung cancer, prostate cancer and others. 
As part of these broader tazemetostat development efforts, we are conducting a global, multi-center, open-label 
randomized Phase 1b/2 trial (EZH-1101, CELLO-1). The Phase 2 efficacy portion of the CELLO-1 trial, which is 
evaluating tazemetostat plus enzalutamide compared to enzalutamide monotherapy in patients with metastatic 
castration-resistant prostate cancer, or mCRPC, is approximately 75% enrolled toward a target of 80 patients and we 
expect to complete enrollment in the Phase 2 portion of the trial in 2022. We plan to provide updated data from the 
safety run-in portion of the trial as well as interim data from the Phase 2 portion of the trial in the second half of 
2022. 
We own the global development and commercialization rights to tazemetostat outside of Japan and greater China. 
Eisai Co. Ltd, or Eisai, holds the rights to develop and commercialize tazemetostat in Japan, and Hutchison China 
MediTech Investment Limited, or HutchMed, holds certain rights to develop and commercialize tazemetostat in 
greater China.
TAZVERIK is available to eligible patients in the United States via a specialty distribution network. Through this 
specialty distribution network, we sell TAZVERIK principally to a limited number of specialty pharmacies, which 
dispense the product directly to patients, and specialty distributors, which in turn sell the product to hospital 
pharmacies and community practice pharmacies for the treatment of patients. To commercialize TAZVERIK for the 
approved ES and FL indications in the United States, we have built a focused field presence and marketing 
capabilities.
On August 7, 2021, we entered into a strategic collaboration pursuant to a license agreement with HutchMed 
through which we granted a license to HutchMed for the co-exclusive (with us) development and exclusive 
commercialization of tazemetostat, either as monotherapy or as a part of combinations with other therapies, 
including HutchMed proprietary compounds, agreed by us and HutchMed for the treatment of ES, FL and DLBCL 
in humans, and any additional indications agreed to by us and HutchMed in mainland China, Taiwan, Hong Kong 
and Macau, or the HutchMed Territory.

96
For other geographies outside the United States, we are evaluating the most efficient path to obtain marketing 
approval, commercialize and distribute TAZVERIK to reach patients, including pursuing potential strategic 
collaborations. Based on comparators and the regulatory landscape, we have decided not to pursue marketing 
approval of tazemetostat as monotherapy from the European Medicines Agency, or EMA at this time. 
Beyond tazemetostat, we are utilizing our drug discovery platform to progress preclinical efforts and discover and 
identify additional product candidates to expand our pipeline of inhibitors against several classes of chromatin 
modifying proteins, or CMPs, including HMTs, histone acetyltransferases, or HATs, and helicases.
Our most advanced product candidate, EZM0414, is a novel first-in-class oral inhibitor of the SETD2 HMT.
SETD2 is an HMT that plays multiple important roles in oncogenesis. Based on the potential of SETD2 inhibition 
demonstrated in multiple preclinical settings, including multiple myeloma, and in particular high risk t(4;14) 
multiple myeloma and in other B-cell malignancies such as DLBCL, as well as in combination with existing and 
emerging therapies including tazemetostat, we submitted an IND for EZM0414 to the FDA in July 2021. We 
received “study may proceed” from the FDA with respect to our IND for EZM0414 in July 2021. In October 2021, 
EZM0414 was granted Fast Track designation by the FDA in adult patients with relapsed or refractory DLBCL and 
in January 2022 we received orphan drug designation from the FDA for EZM0414 for the treatment of multiple 
myeloma. In the fourth quarter of 2021, we initiated a Phase 1/1b trial (SET-101) intended to evaluate the safety and 
optimize the dose and schedule of EZM0414 in R/R multiple myeloma and DLBCL patients. The Phase 1 portion of 
our SET-101 trial is a 3 + 3 dose escalation design and includes six planned dose levels ranging from 100 mg to 900 
mg once daily. Once we have optimized the dose, we then expect to expand the trial to two patient cohorts in 
multiple myeloma: t(4;14) multiple myeloma and non t(4;14) multiple myeloma. Based on dose optimization data 
from the trial, we may add a third patient cohort in DLBCL. We are screening patients with one site open for the 
Phase 1 dose escalation portion of the SET-101 trial, which we expect will enroll between 30-36 patients. We plan 
to provide updates as the trial reaches key enrollment milestones along with preliminary data from the trial in 2022. 
To date we have entered into various strategic collaborations, including with Eisai, HutchMed, Roche and other 
third parties. As one of several key aspects of our strategy, we plan to continue to leverage our existing 
collaborations and to seek to identify new potential strategic collaborations to further support and grow our business 
in and outside of the United States.
Through December 31, 2021, in addition to revenues from product sales, we have raised an aggregate of $1,568.3 
million to fund our operations. This includes $268.8 of non-equity funding through our collaboration agreements, 
$368.1 million of funding, consisting of $150.0 million in equity funding received through agreements with RPI 
Finance Trust, or RPI, and $218.1 million in debt financing received through a loan agreement with BioPharma 
Credit Investments V (Master) LP and BPCR Limited Partnership (as transferee of BioPharma Credit Investments V 
(Master) LP’s interest as a lender), or the Lenders, $855.4 million from the sale of common stock and series A 
convertible preferred stock in our public and at-the-market offerings and $76.0 million from the sale of redeemable 
convertible preferred stock in private financings prior to our initial public offering in May 2013. 

97
As of December 31, 2021, we had $176.8 million in cash, cash equivalents and marketable securities. In January 
2022, the Company raised approximately $79.5 million in net proceeds (after deducting underwriting discounts and 
commissions and estimated offering costs) from the sale of 56,666,667 shares of its common stock in a public 
offering at a price of $1.50 per share.
We commenced active operations in early 2008, and since inception, have incurred significant operating losses. Our 
net loss was $251.1 million for the year ended December 31, 2021. As of December 31, 2021, our accumulated 
deficit totaled $1,239.8 million. Notwithstanding our sales of TAZVERIK, we expect to continue to incur significant 
expenses and operating losses over the next several years. Our net losses may fluctuate significantly from quarter to 
quarter and year to year. We expect our expenses to increase in connection with our ongoing activities, particularly 
as we expect to incur significant commercialization expenses related to product manufacturing, marketing, sales and 
distribution. In addition, we expect our expenses to increase as we fund our tazemetostat development program; 
make any milestone and royalty payments provided for and achieved under the amended and restated collaboration 
and license agreement with Eisai; pay interest and principal associated with our amended and restated loan 
agreement with BioPharma Credit Investments V (Master) LP, BPCR Limited Partnership and BioPharma Credit 
PLC, or the Amended and Restated Loan Agreement; and continue research and development and initiate clinical 
trials of, and seek regulatory approval for, any future product candidates.
Funding Agreements with BioPharma Credit Investments V (Master) LP, BPCR Limited Partnership, 
BioPharma Credit PLC and RPI Finance Trust
We executed a purchase agreement with RPI on November 4, 2019, or the RPI Purchase Agreement. Pursuant to the 
RPI Purchase Agreement, we sold to RPI 6,666,667 shares of our common stock and a warrant to purchase up to 
2,500,000 shares of our common stock at an exercise price of $20.00 per share, or the Common Stock Warrant. We 
also sold our rights to receive royalties from Eisai with respect to net sales by Eisai of tazemetostat products in 
Japan, or the Japan Royalty, pursuant to the amended and restated collaboration and license agreement between us 
and Eisai, dated as of March 12, 2015, or the Eisai License Agreement. In consideration for the sale of shares of our 
common stock, the Common Stock Warrant and the Japan Royalty, RPI paid us $100.0 million upon the closing of 
the RPI Purchase Agreement in November 2019. In addition, RPI agreed, in connection with RPI’s acquisition from 
Eisai of the right to receive royalties from us under the Eisai License Agreement, to reduce our royalty obligation by 
low single digits upon the achievement of specified annual net sales levels. We also had the option to sell to RPI 
$50.0 million of shares of common stock for an 18-month period beginning November 4, 2019, or the Put Option. 
On February 11, 2020, we sold 2,500,000 shares of common stock to RPI for an aggregate of $50.0 million in 
proceeds at a sale price of $20.00 per share of common stock pursuant to the Put Option. 
On November 4, 2019, we also entered into a Loan Agreement with BioPharma Credit PLC, or the Collateral Agent, 
and the Lenders, providing for up to $70.0 million in secured term loans to be advanced in up to three tranches, or 
the Loan Agreement. We borrowed $70.0 million in the aggregate under the three tranches pursuant to the Loan 
Agreement. 
On November 3, 2020, we, the Collateral Agent and the Lenders amended and restated the Loan Agreement, or, as 
amended and restated, the Amended and Restated Loan Agreement. The Amended and Restated Loan Agreement 
provides for, among other things, an additional secured term loan facility of $150.0 million, or the Tranche D Loan. 
On November 18, 2020, we borrowed the Tranche D Loan. 
The obligations under the Amended and Restated Loan Agreement remain secured by a first priority security interest 
that was granted at the time of the Loan Agreement in and a lien on substantially all of our assets, subject to certain 
exceptions.
The Amended and Restated Loan Agreement contains certain customary representations and warranties, affirmative 
and negative covenants and events of default applicable to us and our subsidiaries. If an event of default occurs and 
is continuing, the Collateral Agent under the Amended and Restated Loan Agreement may, among other things, 
accelerate the loans and foreclose on the collateral. See Note 13, Long-Term Debt, of the notes to our consolidated 
financial statements included in this Annual Report on Form 10-K for a description of the key terms of the Amended 
and Restated Loan Agreement.

98
Collaborations 
Refer to Item 1, Business--Our Collaborations and Note 11, Collaborations, of the notes to our consolidated 
financial statements included in this Annual Report on Form 10-K for a description of the key terms of our 
arrangements with Eisai Co. Ltd, or Eisai, Hutchison China MediTech Investment Limited, or HutchMed, and 
Roche Sequencing Solutions, Inc., or Roche Sequencing. On December 16, 2021, we received a notice of 
termination of our collaboration and license agreement with Glaxo Group Limited, effective March 16, 2022.  
Results of Operations
For a discussion related to the results of operations for 2020 compared to 2019, refer to Part II, Item 7, 
"Management's Discussion and Analysis of Financial Condition and Results of Operations – Results of Operations" 
in our Annual Report on Form 10–K for the year ended December 31, 2020 filed with the SEC on February 23, 
2021.
Revenues 
The following is a comparison of total revenues for the years ended December 31, 2021 and 2020: 
Year Ended December 31,
2021
2020
Change
(In millions)
Product revenues, net
$
30.9
$
11.5
$
19.4
Collaboration and other revenue
6.5
4.3
2.2
Total revenues
$
37.4
$
15.8
$
21.6
Product Revenues, net
Net product revenues represent U.S. sales from our sole commercial product, TAZVERIK, which was first approved 
by the FDA on January 23, 2020, less allowances and accruals. During the years ended December 31, 2021, and 
2020 net product revenues were $30.9 million and $11.5 million, respectively. The $19.4 million increase reflects 
the timing of approval of TAZVERIK for ES in January 2020 and the approval of TAZVERIK for FL in June 2020. 
The increase also reflects the inclusion of $7.4 million in product revenue during the year ended December 31, 2021 
related to the sale of commercial product by one of our customers to a third-party pharmaceutical company for use 
in its clinical trials. Sales allowances and accruals consisted of patient financial assistance, distribution fees, 
discounts, and chargebacks. 
Collaboration and Other Revenue 
Our collaboration and other revenue during the periods included amounts recognized from deferred revenue related 
to upfront payments for licenses or options to obtain licenses in the future, research and development services 
revenue earned, milestone payments earned under collaboration and license agreements with our collaboration 
partners and revenue from the sale of tazemetostat active pharmaceutical ingredient (API) and drug product to our 
licensees and collaborators.
During the years ended December 31, 2021 and 2020, we recognized $6.5 million and $4.3 million, respectively, in 
collaboration and other revenue. In 2021 we recognized $6.5 million in collaboration and other revenue in 
connection with our waiver of our exclusive right to the supply of tazemetostat drug substance from Eisai’s 
manufacturer, the manufacture and supply of tazemetostat, and technical support services under our supply 
agreement with Eisai. In 2020 we recognized $3.8 million of collaboration and other revenue under our 
collaboration agreement with Celgene related to the recognition of the remaining deferred revenue related to the 
agreement, which was recognized as revenue as a result of the termination of the collaboration agreement with 
Celgene. We recognized $0.5 million in collaboration and other revenue under our collaboration agreement with 
Boehringer Ingelheim during the year ended December 31, 2020 related to amendments to extend the research 
period under the collaboration agreement under which Boehringer Ingelheim funded $0.5 million of additional 

99
research activities. In December 2020, we received written notice from Boehringer Ingelheim to terminate the 
collaboration agreement, effective January 31, 2021. 
Cost of Revenue
The following is a comparison of cost of revenue for the years ended December 31, 2021 and 2020:
Year Ended December 31,
2021
2020
Change
(In millions)
Cost of product revenue
$
9.7
$
5.1
$
4.6
Cost of other revenue
0.8
-
0.8
Total cost of revenue
$
10.5
$
5.1
$
5.4
The cost of revenue consists of costs related to our product revenue and other revenue for the sales of TAZVERIK 
as well as tazemetostat drug product and drug substance. These costs include materials, labor, manufacturing 
overhead, amortization of milestone payments, and royalties payable on net sales of TAZVERIK and sales of 
tazemetostat drug product. Costs related to the sale of TAZVERIK are included in cost of product revenue while 
cost related to the sale of tazemetostat drug product and drug substance are included in cost of other revenue. 
During the years ended December 31, 2021 and 2020, the cost of product revenue was $9.7 million and $5.1 million, 
respectively, and consisted of $0.9 million and $0.4 million, respectively, in costs associated with manufacturing 
TAZVERIK, $4.2 million and $3.0 million, respectively, in amortization expense related to the two $25.0 million 
milestone payments under our agreement with Eisai upon regulatory approval of TAZVERIK for ES and upon 
regulatory approval of TAZVERIK for FL, and $4.6 million and $1.7 million, respectively, in worldwide royalties 
due under the Eisai License Agreement on net sales of TAZVERIK in the year ended December 31, 2021. Cost of 
other revenue during the year ended December 31, 2021 consisted of $0.8 million of costs related to sales of 
tazemetostat drug product to Eisai. All product costs incurred prior to FDA approval of TAZVERIK in January 2020 
were expensed as research and development expenses. We expect our cost of product revenues (excluding 
amortization of intangible assets) to continue to be positively impacted during 2022, as we sell through certain 
inventory that was expensed prior to FDA approval of TAZVERIK in January 2020. 
Research and Development 
Research and development expenses consist of expenses incurred in performing research and development activities, 
including clinical trials and related clinical manufacturing expenses, fees paid to external providers of research and 
development services, third-party clinical research organizations, or CROs, compensation and benefits for full-time 
research and development employees, facilities expenses, overhead expenses, and other outside expenses. Most of 
our research and development costs are external costs, which we track on a program-by-program basis. Our internal 
research and development costs are primarily compensation expenses for our full-time research and development 
employees, including stock-based compensation expense. 
In our early-stage research, we identify and prioritize novel CMPs that are implicated in cancer, and seek to develop 
potent and selective small molecule inhibitors of these targets. During this phase of research, our external costs 
primarily relate to lead discovery, biology, drug metabolism and pharmacokinetics and chemistry services from a 
multinational network of third-party providers of research and development services. As our product candidates 

100
progress into preclinical and clinical development, external costs are driven by clinical trial costs, manufacturing 
expenses, and third-party research and development expenses. 
In circumstances where our collaboration and license agreements provide for equally co-funded global development 
under joint risk sharing collaborations, and where we are the study sponsor, amounts received for co-funding are 
recorded as a reduction to research and development expense. 
The following is a comparison of research and development expenses for the years ended December 31, 2021 and 
2020 : 
 
Year Ended December 31,
2021
2020
Change
%
(In millions)
Research and development
$
131.0 $
110.9 $
20.1
18.1%
During the year ended December 31, 2021, total research and development expenses increased by $20.1 million 
compared to the year ended December 31, 2020, primarily due to increases in clinical trial expenses and discovery 
research activities related to tazemetostat in indications other than the approved indications as well as our SETD2 
inhibitor EZM0414 program. Additionally, severance and termination-related costs totaling $0.4 million were 
recorded as research and development expenses in 2021 related to the August 2021 cost reduction plan. Increases in 
research and development expenses were partially offset by decreases in costs associated with the build-out of our 
regulatory and late-stage development groups.
The following table illustrates the components of our research and development expenses: 
Year Ended December 31,
Product Program
2021
2020
Change
%
(In millions)
External research and development expenses:
Tazemetostat and related EZH2 programs
$
54.1 $
42.0 $
12.1
28.8%
 SETD2 inhibitor EZM0414 program
2.0
—
2.0
100.0
Discovery and preclinical stage product 
programs, collectively
19.4
17.8
1.6
9.0
Unallocated personnel and other expenses
55.5
51.1
4.4
8.6
Total research and development expenses
$
131.0 $
110.9 $
20.1
18.1%
External research and development expenses include external manufacturing costs related to the acquisition of active 
pharmaceutical ingredient and manufacturing of clinical drug supply, ongoing clinical trial costs, discovery and 
preclinical research in support of the tazemetostat program and expenses associated with our SETD2 inhibitor 
EZM0414 program. 
External research and development expenses for tazemetostat and related EZH2 programs increased by $12.1 
million for the year ended December 31, 2021 compared to the year ended December 31, 2020. The increase in 
external tazemetostat and related EZH2 programs research and development expenses in the year ended 
December 31, 2021 relates to increases in clinical trial expenses and discovery research activities related to 
tazemetostat in other indications associated with increased clinical trial activity, which were offset by decreases in 
costs associated with the build-out of our regulatory and late-stage development groups that we conducted in 2020.
External research and development expenses for our EZM0414 SETD2 inhibitor program increased $2.0 million for 
the year ended December 31, 2021 compared to the 2020. We designated the program as a clinical development 
program in the third quarter of 2021. Prior to the designation of the program as a clinical development program, we 
allocated costs related to the EZM0414 program to external research and development expenses for discovery and 
preclinical stage product programs.
External research and development expenses for discovery and preclinical stage product programs increased by $1.6 
million for the year ended December 31, 2021 compared to the year ended December 31, 2020, was primarily 

101
related to increased spending for discovery research activities and development activities related to our preclinical 
programs, partially offset by reduced preclinical costs in connection with our EZM0414 SETD2 inhibitor program 
as a result of the designation of the EZM0414 SETD2 inhibitor program as a clinical development program in the 
third quarter of 2021.
Unallocated personnel and other expenses are comprised of compensation expenses for our full-time research and 
development employees and other general research and development expenses. Unallocated personnel and other 
expenses for the year ended December 31, 2021 increased $4.4 million compared to the year ended December 31, 
2020. The increase is a result of increases in facilities and equipment related expenses and in unallocated personnel 
costs, offset by an increase in the allocation of expenses to projects. 
We expect that research and development expenses will decrease in 2022, as we continue to implement our 
operating expense reductions and prioritize our investment of company resources in important clinical trials and 
programs, including our SYMPHONY-1 (EZH-302) and CELLO-1 (EZH-1101), EZH-1501 and SET-101 trials.
Selling, General and Administrative 
Selling, general and administrative expenses consist primarily of salaries and related benefits, including stock-based 
compensation, related to our executive, finance, intellectual property, business development and support functions. 
Other selling, general and administrative expenses include allocated facility-related costs not otherwise included in 
research and development expenses, travel expenses and professional fees for auditing, tax and legal services, 
including intellectual property and general legal services. 
The following is a comparison of selling, general and administrative expenses for the years ended December 31, 
2021 and 2020 : 
Year Ended December 31,
2021
2020
Change
%
(In millions)
Selling, general and administrative
$ 134.0
$
125.2
$
8.8
7.0%

102
For the year ended December 31, 2021, our selling, general and administrative expenses increased $8.8 million 
compared to the year ended December 31, 2020, primarily due to increased commercialization activities, including 
the build-out of our sales force and commercial infrastructure to support the commercial launch of TAZVERIK in 
the approved ES and FL indications, and increased personnel related expenses. Additionally, severance and 
termination-related costs totaling $1.6 million were recorded as selling, general and administrative expenses in 2021 
related to the August 2021 cost reduction plan.
We expect that selling, general and administrative expenses will decrease in 2022 as we implement changes to our 
commercial strategy and organization in an effort to accelerate commercial adoption of TAZVERIK in appropriate 
patients as well as an operational cost reduction across general and administrative functions as part of our 
prioritization of our investment of company resources in important clinical trials and programs.
Other (Expense) Income, Net 
The following is a comparison of other (expense) income, net for the years ended December 31, 2021 and 2020: 
Year Ended December 31,
2021
2020
Change
%
(In millions)
Other income, net
Interest income
$
0.2
$
2.9
$
(2.7)
(93.1)%
Interest expense
(22.5)
(7.6)
(14.9)
196.1
Other expense, net
(0.1)
(0.1)
—
-
Change in fair value of warrants to purchase common 
stock
11.1
—
11.1
100.0
Non-cash interest expense related to sale of future 
royalties
(1.8)
(1.4)
(0.4)
28.6
Other (expense) income, net
$
(13.1)
$
(6.2)
$
(6.9)
111.3%
Other (expense) income, net consists of interest income earned on our cash equivalents and marketable securities, 
net of imputed interest expense paid under our capital lease obligation. The increase in other expense for the year 
ended December 31, 2021 is principally due to an increase in interest expense of $15.0 million incurred in 
connection with our long-term debt obligations under our Amended and Restated Loan Agreement which increased 
to a principal balance of $220.0 million in the fourth quarter of 2020, a decrease in net interest income of $2.6 
million due to a combination of lower cash, cash equivalents and marketable securities combined with lower rates of 
return, and an increase in non-cash interest expense related to the sale of future royalties of $0.4 million. These 
increases in other expense were offset by income related to the changes in fair value of warrant liability of $11.1 
million due to a decrease in our stock price. 
Income Tax Benefit 
We evaluated the expected recoverability of our net deferred tax assets as of December 31, 2021 and 2020, and 
determined that there was insufficient positive evidence to support the recoverability of these net deferred tax assets, 
concluding it is more likely than not that our net deferred tax assets would not be realized in the future; therefore, 
the Company provided a full valuation allowance against its net deferred tax asset balance as of December 31, 2021 
and 2020. 

103
Liquidity and Capital Resources 
For a discussion related to our cash flows for 2020 compared to 2019, refer to Part II, Item 7, "Management's 
Discussion and Analysis of Financial Condition and Results of Operations – Liquidity and Capital Resources" in 
our Annual Report on Form 10–K for the year ended December 31, 2020 filed with the SEC on February 23, 2021
Through December 31, 2021, in addition to revenues from product sales, we have raised an aggregate of $1,568.3 
million to fund our operations. This includes $268.8 million in non-equity funding through our collaboration 
agreements, $368.1 million of funding, consisting of $150.0 million in equity funding received through agreements 
with RPI Finance Trust, or RPI, and $218.1 million in debt financing received through a loan agreement with 
BioPharma Credit Investments V (Master) LP and BPCR Limited Partnership (as transferee of BioPharma Credit 
Investments V (Master) LP’s interest as a lender), or the Lenders, $855.4 million from the sale of common stock and 
series A convertible preferred stock in our public offerings and at-the-market offerings and $76.0 million was from 
the sale of redeemable convertible preferred stock in private financings prior to our initial public offering in May 
2013. As of December 31, 2021, we had $176.8 million in cash, cash equivalents and marketable securities. 
On May 6, 2021, we entered into an Open Market Sale AgreementSM, or ATM Sale Agreement, with Jefferies LLC, 
or Jefferies, to sell, from time to time, shares of our common stock having an aggregate offering price of up to 
$200,000,000 through an “at the market offering” as defined in Rule 415 under the Securities Act of 1933, as 
amended, under which Jefferies would act as sales agent, which we refer to as the ATM Offering. The shares that 
may be sold under the ATM Sale Agreement, if any, are issued and sold pursuant to our shelf registration statement 
on Form S-3 that was declared effective by the Securities and Exchange Commission on May 13, 2021. Through 
December 31, 2021, we have sold a total of 3,840,977 shares under the ATM Offering, resulting in aggregate net 
proceeds to us of approximately $16.0 million after deducting issuance costs of $0.5 million. 
In addition to our existing cash, cash equivalents and marketable securities, we are eligible to earn milestone 
payments under our collaboration agreement with HutchMed. Our ability to earn these payments and the timing of 
earning these payments is dependent upon the outcome of research and development activities and is uncertain at 
this time.
In January 2022, we raised approximately $79.5 million in net proceeds (after deducting underwriting discounts and 
commissions and estimated offering costs, but excluding any expenses and other costs reimbursed by the 
underwriters) from the sale of 56,666,667 shares of our common stock in a public offering at a price of $1.50 per 
share.
Funding Requirements 
Our primary uses of capital are clinical trial costs, third-party research and development services, expenses related to 
commercialization, debt service obligations, compensation and related expenses, laboratory and related supplies, 
legal and other regulatory expenses and general overhead costs. 
Because the continued approval of TAZVERIK in the approved indications is contingent upon verification and 
description of clinical benefit in confirmatory trials, and because we are developing tazemetostat for other 
indications, we cannot estimate the actual amounts necessary to successfully complete the development and 
commercialization of TAZVERIK for the approved indications or the indications that we are exploring or that we 
may plan to explore. Because EZM0414 is an early clinical product candidate and any future product candidates are 
in various stages of preclinical development with uncertain outcomes, we also cannot estimate the actual amounts 
necessary to successfully complete the development and commercialization of EZM0414 or future product 
candidates. Because of these uncertainties, we also cannot estimate whether, or when, we may achieve profitability. 
Until such time, if ever, as we can generate substantial product revenues, we expect to finance our cash needs 
through a combination of equity or debt financings and collaboration arrangements. Except for any obligations of 
our collaborators to make license, milestone or royalty payments under our agreements with them, we do not have 
any committed external sources of liquidity. To the extent that we raise additional capital through the future sale of 
equity or debt, the ownership interest of our stockholders may be diluted, and the terms of these securities may 
include liquidation or other preferences that adversely affect the rights of our existing common stockholders. Debt 

104
financing and preferred equity financing, if available, may involve agreements that include covenants limiting or 
restricting our ability to take specific actions, such as incurring additional debt, making capital expenditures or 
declaring dividends. If we raise additional funds through collaboration arrangements in the future, we may have to 
relinquish valuable rights to our technologies, future revenue streams or product candidates or grant licenses on 
terms that may not be favorable to us. If we are unable to raise any additional funds that may be needed through 
equity or debt financings when needed, we may be required to delay, limit, reduce or terminate our product 
development or future commercialization efforts or grant rights to develop and market product candidates that we 
would otherwise prefer to develop and market ourselves. 
Outlook 
Based on our current operating plan, we expect that our existing cash, cash equivalents and marketable securities as 
of December 31, 2021, together with the $79.5 million in net proceeds raised from the common stock offering in 
January 2022 and cash we expect to generate from product sales, will be sufficient to fund our planned operating 
expenses and capital expenditure requirements and pay our debt service obligations as they become due into the 
third quarter of 2023, without giving effect to any potential milestone payments we may receive under our 
collaboration agreements. We have based this estimate on assumptions that may prove to be wrong, such as the 
revenue that we expect to generate from the sale of our products, or as to our clinical development costs, particularly 
as the process of testing drug candidates in clinical trials is costly and the timing of progress in these trials is 
uncertain. As a result, we could use our capital resources sooner than we expect. 
Cash Flows 
The following is a summary of cash flows for the years ended for the years ended December 31, 2021 and 2020: 
Year Ended December 31,
2021
2020
Change
%
(In millions)
Net cash (used in) operating activities
$
(226.9) $
(206.3) $
(20.6)
10.0%
Net cash provided by (used in) investing activities
125.5
(14.6)
140.1
(959.6%)
Net cash provided by financing activities
31.5
249.7
(218.2)
(87.4%)
Net Cash Used in Operating Activities 
Net cash used in operating activities was $226.9 million during the year ended December 31, 2021 compared to 
$206.3 million during the year ended December 31, 2020. The increase in net cash used in operating activities of 
$20.6 million primarily relates to our net loss of $251.1 million and the $11.1 million change in fair value of 
warrants, partially offset by changes in working capital of $0.2 million, net depreciation and amortization of $5.2 
million, non-cash stock-based compensation of $26.8 million, and non-cash interest expense associated with the sale 
of future royalties of $1.8 million.
Net Cash Provided by (Used in) Investing Activities 
Net cash provided by investing activities during the year ended December 31, 2021 reflects maturities of available-
for-sale securities of $388.6 million, offset by $262.6 million of purchases of available-for-sale securities, and $0.5 
million of purchases of property and equipment.
Net cash used in investing activities during the year ended December 31, 2020 reflects $276.4 million of purchases 
of available for sale securities, a $25.0 million milestone payment under the Eisai collaboration agreement upon 
regulatory approval of tazemetostat for ES, a $25.0 million milestone payment under the Eisai collaboration 
agreement upon regulatory approval of tazemetostat for FL, and $0.9 million of purchases of property and 
equipment, offset by maturities and sales of available for sale securities of $312.7 million.

105
Net Cash Provided by Financing Activities 
Net cash provided by financing activities of $31.5 million during the year ended December 31, 2021 primarily 
reflects net proceeds from the sale of common stock under the ATM Sale Agreement of $16.0 million, the purchases 
of shares under our employee stock purchase plan of $1.9 million, stock option exercises of $0.9 million, and $13.1 
million from the issuance of the HutchMed Warrant, partially offset by the payment of offering costs of $0.3 million 
related to the ATM program.
Net cash provided by financing activities of $249.7 million during the year ended December 31, 2020 primarily 
reflects cash received from the sale of common stock of $50.0 million in connection with our exercise of our Put 
Option to sell shares of our common stock to Royalty Pharma, net cash received during the period from Tranche B 
Tranche C and Tranche D Loan borrowings totaling $195.0 million under the Amended and Restated Loan 
Agreement, stock option exercises of $6.7 million, and the purchases of shares under our employee stock purchase 
plan of $1.3 million, partially offset by payments of debt issuance costs of $3.1 million and offering costs of $0.1 
million.
Contractual Obligations and Contingent Liabilities 
On August 11, 2021, we entered into a fifth amendment to the Technology Square Lease, the Fifth Amendment, 
with ARE-TECH Square, LLC. Under the Fifth Amendment, we extended the term of the Technology Square Lease 
through November 30, 2024. Under the Fifth Amendment, we will continue to pay the current monthly base rent 
amount contemplated by the Technology Square Lease through November 30, 2022, with an increase commencing 
on December 1, 2022 and adjusting the monthly base rent amount to approximately $377,000 and an increase 
commencing on December 1, 2023 and adjusting the monthly base rent amount to approximately $388,000 through 
November 30, 2024. Under the current terms of the Technology Square Lease, we do not have any further right to 
extend the term beyond November 30, 2024.
We remain committed to fund $1.0 million of development costs payable to Roche Molecular, or Roche, upon 
certain development and regulatory milestones, under our amended companion diagnostic agreement with Roche. 
We have incurred secured indebtedness of $220.0 million under our amended and restated loan agreement with 
BioPharma Credit Investments V (Master) LP, BPCR Limited Partnership and BioPharma Credit PLC. The interest 
rate for the loans under the agreement are determined by reference to a Eurodollar rate plus 7.75% above such 
Eurodollar rate subject to a 2.00% floor. Interest is paid quarterly with principal repayments beginning in the first 
quarter of 2024. Our long-term debt obligation is more fully described in Note 13, Long-Term Debt to the financial 
statements in Item 15 of this Annual Report on Form 10-K. 
This description of our contractual obligations does not include potential future milestones or royalties that we may 
be required to make under license and collaboration agreements due to the uncertainty of events requiring payment 
under these agreements. 
We enter into contracts in the normal course of business with clinical research organizations for clinical and 
preclinical research studies, external manufacturers for product for use in our clinical trials, and other research 
supplies and other services as part of our operations. These contracts generally provide for termination on notice, 
and therefore are cancelable contracts and not included in contractual commitments. 
Critical Accounting Policies and Use of Estimates 
Our management’s discussion and analysis of financial condition and results of operations is based upon our 
consolidated financial statements, which have been prepared in accordance with accounting principles generally 
accepted in the United States of America. The preparation of these consolidated financial statements requires us to 
make estimates, judgments and assumptions that affect the reported amounts of assets and liabilities and disclosures 
of contingent assets and liabilities as of the date of the balance sheets and the reported amounts of collaboration 
revenue, inventory and expenses during the reporting periods. We base our estimates on historical experience and on 
various other assumptions that we believe to be reasonable under the circumstances at the time such estimates are 
made. Actual results and outcomes may differ materially from our estimates, judgments and assumptions. We 

106
periodically review our estimates in light of changes in circumstances, facts and experience. The effects of material 
revisions in estimates are reflected in the consolidated financial statements prospectively from the date of the change 
in estimate. 
We define our critical accounting policies as those accounting principles generally accepted in the United States of 
America that require us to make subjective estimates and judgments about matters that are uncertain and are likely 
to have a material impact on our financial condition and results of operations as well as the specific manner in which 
we apply those principles. Management has determined that our most critical accounting policies are those relating 
to revenue recognition, research and development expenses, including our accounting for clinical trial expense and 
accruals, inventory and going concern. As our clinical development plan for tazemetostat and EZM0414 progresses, 
we expect research and development expenses and, in particular, our accounting for clinical trial accruals to be an 
increasingly important critical accounting policy. 
Revenue Recognition – Product Revenue
We recognize revenue when our customer obtains control of promised goods or services, in an amount that reflects 
the consideration which we expect to receive in exchange for those goods or services. To determine revenue 
recognition, we perform the following five steps: (i) identify the contract(s) with a customer; (ii) identify the 
performance obligations in the contract; (iii) determine the transaction price; (iv) allocate the transaction price to the 
performance obligations in the contract; and (v) recognize revenue when (or as) we satisfy a performance obligation. 
We only apply the five-step model to contracts when it is probable that we will collect the consideration we are 
entitled to in exchange for the goods or services we transfer to the customer. 
We sell TAZVERIK in the United States principally to a limited number of specialty pharmacies, which dispense 
the product directly to patients, and specialty distributors, which in turn sell the product to hospital pharmacies and 
community practice pharmacies (collectively, healthcare providers) for the treatment of patients. The specialty 
pharmacies and specialty distributors are referred to as our customers.
Revenue is recognized by us when the customer obtains control of the product, which occurs at a point in time, 
typically when the product is received by our customers. We provide a right of return to our customers for unopened 
product for a limited time before and after its expiration date, which lapses upon shipment to a patient. Healthcare 
providers to whom specialty distributors sell TAZVERIK hold limited inventory that is designated for patients, and 
we are able to monitor inventory levels in the distribution channel, thereby limiting the risk of return.
 
Reserves for Variable Consideration 
Revenues from product sales are recorded at the net sales price (transaction price), which includes estimates of 
variable consideration for which reserves are established and which result from discounts, returns, chargebacks, 
rebates, co-pay assistance and other allowances that are offered within contracts between us and our customers, 
health care providers, payors and other indirect customers relating to our product sales. These reserves are based on 
the amounts earned or to be claimed on the related sales and are classified as reductions of accounts receivable (if 
the amount is payable to the customer) or a current liability (if the amount is payable to a party other than a 
customer). Where appropriate, these estimates take into consideration a range of possible outcomes that are 
probability-weighted for relevant factors such as our historical experience, current contractual and statutory 
requirements, specific known market events and trends, industry data and forecasted customer buying and payment 
patterns. Overall, these reserves reflect our best estimates of the amount of consideration to which we are entitled 
based on the terms of the contract. The amount of variable consideration that is included in the transaction price may 
be constrained, and is included in the net sales price only to the extent that it is probable that a significant reversal in 
the amount of the cumulative revenue recognized will not occur in a future period. Actual amounts of consideration 
ultimately received may differ from our estimates. If actual results in the future vary from our estimates, we will 
adjust these estimates, which would affect net product revenue and earnings in the period such variances become 
known.
Trade Discounts and Allowances: We generally provide customers with discounts that include incentive fees that are 
explicitly stated in our contracts and are recorded as a reduction of revenue in the period the related product revenue 
is recognized. In addition, we receive sales order management, data and distribution services from certain customers. 
To the extent the services received are distinct from our sale of products to the customer, these payments are 

107
classified in selling, general and administrative expenses in the consolidated statements of operations and 
comprehensive loss.
Product Returns: Consistent with industry practice, we generally offer customers a limited right of return based on 
the product’s expiration date for product that has been purchased from us, which lapses upon shipment to a patient. 
We estimate the amount of our product sales that may be returned by our customers and record this estimate as a 
reduction of revenue in the period the related product revenue is recognized. We currently estimate product return 
liabilities using available industry data and our own historical sales information, including our visibility into the 
inventory remaining in the distribution channel.
Provider Chargebacks and Discounts: Chargebacks for fees and discounts to providers represent the estimated 
obligations resulting from contractual commitments to sell products to qualified healthcare providers at prices lower 
than the list prices charged to customers who directly purchase the product from us. Customers charge us for the 
difference between what they pay for the product and the ultimate selling price to the qualified healthcare providers. 
These reserves are established in the same period that the related revenue is recognized, resulting in a reduction of 
product revenue and accounts receivable. Chargeback amounts are generally determined at the time of resale to the 
qualified healthcare provider by customers, and we generally issue credits for such amounts within a few weeks of 
the customer’s notification to us of the resale. Reserves for chargebacks consist of credits that we expect to issue for 
units that remain in the distribution channel inventories at each reporting period end that we expect will be sold to 
qualified healthcare providers, and chargebacks that customers have claimed but for which we have not yet issued a 
credit.
Government Rebates: We are subject to discount obligations under state Medicaid programs and Medicare. We 
estimate our Medicaid and Medicare rebates based upon a range of possible outcomes that are probability-weighted 
for the estimated payor mix. These reserves are recorded in the same period the related revenue is recognized, 
resulting in a reduction of product revenue and the establishment of a current liability that is included in accrued 
expenses on the consolidated balance sheet. For Medicare, we also estimate the number of patients in the 
prescription drug coverage gap for whom we will owe an additional liability under the Medicare Part D program. 
Our liability for these rebates consists of invoices received for claims from prior quarters that have not been paid or 
for which an invoice has not yet been received, estimates of claims for the current quarter, and estimated future 
claims that will be made for product that has been recognized as revenue, but remains in the distribution channel 
inventories at period end.
Payor Rebates: We may contract with various private payor organizations, primarily insurance companies and 
pharmacy benefit managers, for the payment of rebates with respect to utilization of our products. We estimate these 
rebates and record such estimates in the same period the related revenue is recognized, resulting in a reduction of 
product revenue and the establishment of a current liability.
Other Incentives/Patient Assistance Programs: We also offer voluntary patient assistance programs such as co-pay 
assistance. Co-pay assistance programs are intended to provide financial assistance to qualified commercially 
insured patients with prescription drug co-payments required by payors. The calculation of the accrual for co-pay 
assistance is based on an estimate of claims and the cost per claim that we expect to receive associated with product 
that has been recognized as revenue, but remains in in the distribution channel inventories at period end.
Revenue Recognition – Collaboration Revenue
Effective January 1, 2018, we adopted ASC, Topic 606, Revenue from Contracts with Customers, or ASC 606, using 
the modified retrospective transition method. Under this method, results for reporting periods beginning after 
January 1, 2018 are presented pursuant to ASC 606, while prior period amounts are not adjusted and continue to be 
reported in accordance with ASC 605. This standard applies to all contracts with customers, except for contracts that 
are within the scope of other standards, such as leases, insurance, collaboration arrangements and financial 
instruments. Under ASC 606, an entity recognizes revenue when its customer obtains control of promised goods or 
services, in an amount that reflects the consideration which the entity expects to receive in exchange for those goods 
or services. To determine revenue recognition for arrangements that an entity determines are within the scope of 
ASC 606, the entity performs the following five steps: (i) identify the contract(s) with a customer; (ii) identify the 

108
performance obligations in the contract; (iii) determine the transaction price; (iv) allocate the transaction price to the 
performance obligations in the contract; and (v) recognize revenue when (or as) the entity satisfies a performance 
obligation. We only apply the five-step model to contracts when it is probable that the entity will collect the 
consideration it is entitled to in exchange for the goods or services it transfers to the customer. At contract inception, 
once the contract is determined to be within the scope of ASC 606, we assess the goods or services promised within 
each contract and determines those that are performance obligations, and assesses whether each promised good or 
service is distinct. We then recognize as revenue the amount of the transaction price that is allocated to the 
respective performance obligation when (or as) the performance obligation is satisfied.
 
We have entered into collaboration and license agreements, which are within the scope of ASC 606, to discover, 
develop, manufacture and commercialize product candidates. The terms of these agreements typically contain 
multiple promises or obligations, which may include: (i) licenses, or options to obtain licenses, to compounds 
directed to specific targets (referred to as “exclusive licenses”) and (ii) research and development activities to be 
performed on behalf of the collaboration partner related to the licensed targets. Payments to us under these 
agreements may include non-refundable license fees, customer option exercise fees, payments for research activities, 
reimbursement of certain costs, payments based upon the achievement of certain milestones and royalties on any 
resulting net product sales.
 
We first evaluate license and/or collaboration arrangements to determine whether the arrangement (or part of the 
arrangement) represents a collaborative arrangement pursuant to ASC Topic 808, Collaborative Arrangements, 
based on the risks and rewards and activities of the parties pursuant to the contractual arrangement. We account for 
collaborative arrangements (or elements within the contract that are deemed part of a collaborative arrangement), 
which represent a collaborative relationship and not a customer relationship, outside the scope of ASC 606. Our 
collaborations primarily represent revenue arrangements. For the arrangements or arrangement components that are 
subject to revenue accounting guidance, in determining the appropriate amount of revenue to be recognized as it 
fulfills its obligations under each of its agreements, we perform the following steps: (i) identification of the 
promised goods or services in the contract; (ii) determination of whether the promised goods or services are 
performance obligations including whether they are distinct in the context of the contract; (iii) measurement of the 
transaction price, including the constraint on variable consideration; (iv) allocation of the transaction price to the 
performance obligations; and (v) recognition of revenue when (or as) we satisfy each performance obligation. As 
part of the accounting for these arrangements, we must use significant judgment to determine: a) the number of 
performance obligations based on the determination under step (ii) above and whether those performance 
obligations are distinct from other performance obligations in the contract; b) the transaction price under step (iii) 
above; and c) the stand-alone selling price for each performance obligation identified in the contract for the 
allocation of transaction price in step (iv) above. We use judgment to determine whether milestones or other variable 
consideration, except for sales-based royalties, should be included in the transaction price as described further 
below. The transaction price is allocated to each performance obligation on a relative stand-alone selling price basis, 
for which we recognize revenue as or when the performance obligations under the contract are satisfied. In 
determining the stand-alone selling price of a license to our proprietary technology or a material right provided by a 
customer option, we consider market conditions as well as entity-specific factors, including those factors 
contemplated in negotiating the agreements as well as internally developed estimates that include assumptions 
related to the market opportunity, estimated development costs, probability of success and the time needed to 
commercialize a product candidate pursuant to the license. In validating its estimated stand-alone selling price, we 
evaluate whether changes in the key assumptions used to determine its estimated stand-alone selling price will have 
a significant effect on the allocation of arrangement consideration between performance obligations.
Amounts received prior to revenue recognition are recorded as deferred revenue. Amounts expected to be 
recognized as revenue within the 12 months following the balance sheet date are classified as current portion of 
deferred revenue in the accompanying consolidated balance sheets. Amounts not expected to be recognized as 
revenue within the 12 months following the balance sheet date are classified as deferred revenue, net of current 
portion. Amounts recognized as revenue, but not yet received or invoiced are generally recognized as contract 
assets.
Exclusive Licenses – If the license to our intellectual property is determined to be distinct from the other promises or 
performance obligations identified in the arrangement, which generally include research and development services, 
we recognize revenue from non-refundable, upfront fees allocated to the license when the license is transferred to 

109
the customer and the customer is able to use and benefit from the license. In assessing whether a license is distinct 
from the other promises, we consider relevant facts and circumstances of each arrangement, including the research 
and development capabilities of the collaboration partner and the availability of the associated expertise in the 
general marketplace. In addition, we consider whether the collaboration partner can benefit from the license for its 
intended purpose without the receipt of the remaining promises, whether the value of the license is dependent on the 
unsatisfied promises, whether there are other vendors that could provide the remaining promises, and whether it is 
separately identifiable from the remaining promises. For licenses that are combined with other promises, we utilize 
judgment to assess the nature of the combined performance obligation to determine whether the combined 
performance obligation is satisfied over time or at a point in time and, if over time, the appropriate method of 
measuring progress for purposes of recognizing revenue. We evaluate the measure of progress each reporting period 
and, if necessary, adjusts the measure of performance and related revenue recognition. The measure of progress, and 
thereby periods over which revenue should be recognized, are subject to estimates by management and may change 
over the course of the research and development and licensing agreement.
 
Research and Development Services – The promises under our collaboration and license agreements generally 
include research and development services to be performed by us on behalf of the collaboration partner. For 
performance obligations that include research and development services, we generally recognize revenue allocated 
to such performance obligations based on an appropriate measure of progress. We utilize judgment to determine the 
appropriate method of measuring progress for purposes of recognizing revenue, which is generally an input measure 
such as costs incurred. We evaluate the measure of progress each reporting period as described under Exclusive 
Licenses above. Reimbursements from the partner that are the result of a collaborative relationship with the partner, 
instead of a customer relationship, such as co-development activities, are recorded as a reduction to research and 
development expense.
Customer Options – Our arrangements may provide a collaborator with the right to select a target for licensing either 
at the inception of the arrangement or within an initial pre-defined selection period, which may, in certain cases, 
include the right of the collaborator to extend the selection period. Under these agreements, fees may be due to us (i) 
at the inception of the arrangement as an upfront fee or payment, (ii) upon the exercise of an option to acquire a 
license or (iii) upon extending the selection period as an extension fee or payment. If an arrangement is determined 
to contain customer options that allow the customer to acquire additional goods or services, the goods and services 
underlying the customer options are not considered to be performance obligations at the outset of the arrangement, 
as they are contingent upon option exercise. We evaluate the customer options for material rights, or options to 
acquire additional goods or services for free or at a discount. If the customer options are determined to represent a 
material right, the material right is recognized as a separate performance obligation at the inception of the 
arrangement. We allocate the transaction price to material rights based on the relative stand-alone selling price, 
which is determined based on the identified discount and the probability that the customer will exercise the option. 
Amounts allocated to a material right are not recognized as revenue until, at the earliest, the option is exercised or 
expires.
Milestone Payments – At the inception of each arrangement that includes development milestone payments, we 
evaluate whether the milestones are considered probable of being achieved and estimates the amount to be included 
in the transaction price using the most likely amount method. If it is probable that a significant revenue reversal 
would not occur, the associated milestone value is included in the transaction price. Milestone payments that are not 
within our control or the licensee’s control, such as regulatory approvals, are not considered probable of being 
achieved until those approvals are received. We evaluate factors such as the scientific, clinical, regulatory, 
commercial, and other risks that must be overcome to achieve the particular milestone in making this assessment. 
There is considerable judgment involved in determining whether it is probable that a significant revenue reversal 
would not occur. At the end of each subsequent reporting period, we reevaluate the probability of achievement of all 
milestones subject to constraint and, if necessary, adjusts its estimate of the overall transaction price. Any such 
adjustments are recorded on a cumulative catch-up basis, which would affect revenues and earnings in the period of 
adjustment. If a milestone or other variable consideration relates specifically to our efforts to satisfy a single 
performance obligation or to a specific outcome from satisfying the performance obligation, we generally allocate 
the milestone amount entirely to that performance obligation once it is probable that a significant revenue reversal 
would not occur.
Royalties – For arrangements that include sales-based royalties, including milestone payments based on a level of 
sales, and the license is deemed to be the predominant item to which the royalties relate, we recognize revenue at the 

110
later of (i) when the related sales occur or (ii) when the performance obligation to which some or all of the royalty 
has been allocated has been satisfied (or partially satisfied). To date, we have not recognized any royalty revenue 
resulting from any of our licensing arrangements.
For a complete discussion of accounting for collaboration revenues, see Note 11, Collaborations, in the 
accompanying Notes to Consolidated Financial Statements included in Item 15. of Part IV of this Annual Report on 
Form 10-K.
Accrued Research and Development Expenses 
As part of the process of preparing our financial statements, we are required to estimate our accrued expenses as of 
each balance sheet date. This process involves reviewing open contracts and purchase orders, communicating with 
our personnel to identify services that have been performed on our behalf and estimating the level of service 
performed and the associated cost incurred for the service when we have not yet been invoiced or otherwise notified 
of the actual cost. The majority of our service providers invoice us monthly in arrears for services performed or 
when contractual milestones are met. We make estimates of our accrued expenses as of each balance sheet date in 
our financial statements based on facts and circumstances known to us at that time. We periodically confirm the 
accuracy of our estimates with the service providers and make adjustments if necessary. Examples of estimated 
accrued research and development expenses include fees paid to: 

contract research organizations in connection with clinical trials; 

investigative sites in connection with clinical trials; 

vendors in connection with non-clinical development activities; and 

vendors related to product manufacturing, development and distribution of clinical supplies. 
We generally accrue expenses related to research and development activities based on the services received and 
efforts expended pursuant to contracts with multiple contract research organizations that conduct and manage 
clinical trials on our behalf as well as other vendors that provide research and development services. The financial 
terms of these agreements are subject to negotiation, vary from contract to contract and may result in uneven 
payment flows. There may be instances in which payments made to our vendors will exceed the level of services 
provided and result in a prepayment of the expense. Payments under some of these contracts depend on factors such 
as the successful enrollment of subjects and the completion of clinical trial milestones. In accruing service fees, we 
estimate the time period over which services will be performed and the level of effort to be expended in each period. 
If the actual timing of the performance of services or the level of effort varies from our estimate, we would adjust 
the accrual or prepaid accordingly. 
Although we do not expect our estimates to be materially different from amounts actually incurred, if our estimates 
of the status and timing of services performed differ from the actual status and timing of services performed we may 
report amounts that are too high or too low in any particular period. To date, there have been no material differences 
from our estimates to the amount actually incurred. 
Inventory 
We outsource the manufacturing of TAZVERIK and use contract manufacturers to produce the raw and intermediate 
materials used in the production of TAZVERIK as well as the finished product. We currently have one supplier 
qualified for each step in the manufacturing process and are in the process of qualifying additional suppliers. 
Inventory is composed of raw materials, intermediate materials, which are classified as work-in-process, and 
finished goods, which are goods that are available for sale. We state inventory at the lower of cost or net realizable 
value with the cost based on the first-in, first-out method. If we identify excess, obsolete or unsalable items, we 
write down our inventory to its net realizable value in the period in which the impairment is identified. These 
adjustments are recorded based upon various factors related to the product, including the level of product 
manufactured by us, the level of product in the distribution channel, current and projected demand, the expected 

111
shelf-life of the product and firm inventory purchase commitments. Shipping and handling costs incurred for 
inventory purchases are included in inventory costs and costs incurred for product shipments are recorded as 
incurred in cost of product revenue.
Prior to receiving our first approval from the U.S. Food and Drug Administration, or FDA, on January 23, 2020, we 
expensed all costs incurred related to the manufacture of TAZVERIK as research and development expense because 
of the inherent risks associated with the development of a product candidate, the uncertainty about the regulatory 
approval process and the lack of history for us of regulatory approval of drug candidates.
Going Concern 
At each reporting period, we evaluate whether there are conditions or events that raise substantial doubt about the 
Company’s ability to continue as a going concern within one year after the date that the financial statements are 
issued. The Company is required to make certain additional disclosures if it concludes substantial doubt exists about 
the Company's ability to continue as a going concern within one year after the date that the financial statements are 
issued and such doubt is not alleviated by the Company’s plans or when its plans alleviate substantial doubt about 
the Company’s ability to continue as a going concern. The Company’s evaluation entails analyzing prospective 
operating budgets and forecasts for expectations of the Company’s cash needs, and comparing those needs to its 
available cash, cash equivalents and marketable securities.
The analysis of the Company’s ability to continue as a going concern includes consideration of the Company’s 
current cash needs, including its research and development plans, commercialization activities associated with the 
continued commercialization of TAZVERIK in the ES and FL indications, its existing debt service obligations, and 
anticipated cost savings from its operational cost reduction plans, including ongoing efforts to eliminate costs not 
related to the Company’s strategic focus. The analysis includes forecasted product revenues from sales of 
TAZVERIK. Such estimates of future sales contain significant judgment as TAZVERIK was first launched in the 
first half of 2020 and there is little history with which to base such estimates. In addition, the Company’s ongoing 
efforts to eliminate costs not related to the Company’s strategic focus contains uncertainties as to whether the 
Company can attain such benefits. 
Based on its analysis, the Company concluded that its available cash, cash equivalents and marketable securities as 
of December 31, 2021 combined with the $79.5 million raised in January 2022 will be sufficient to fund current 
planned operations and capital expenditure requirements and pay its debt service obligations as they become due 
into the third quarter of 2023, which is at least 12 months from the filing date of this Annual Report on Form 10-K 
with the SEC. As a result, the Company concluded that it did not identify conditions or events that raise substantial 
doubt about the Company’s ability to continue as a going concern within one year from the date these financial 
statements were issued. The Company’s current operating plan is based on assumptions that may prove to be wrong, 
and the Company could use its capital resources sooner than it expects, in which case the Company would evaluate 
further reductions in its expenses or obtaining additional financing sooner than it otherwise would, which additional 
financing may not be available or may only be available on terms that are not acceptable to the Company.
Recently Adopted Accounting Pronouncements 
For detailed information regarding recently issued accounting pronouncements and the expected impact on our 
consolidated financial statements, see Note 2, Summary of Significant Accounting Policies—Recently Adopted 
Accounting Pronouncements, in the accompanying Notes to Consolidated Financial Statements included in Item 15. 
of Part IV of this Annual Report on Form 10-K. 

112
Item 7A. Quantitative and Qualitative Disclosures about Market Risk 
The market risk inherent in our financial instruments and in our financial position represents the potential loss 
arising from adverse changes in interest rates. As of December 31, 2021, we had cash equivalents and available for 
sale securities of $176.8 million consisting of money market funds, corporate bonds, commercial paper and 
government-related obligations. Our primary exposure to market risk is interest rate sensitivity, which is affected by 
changes in the general level of U.S. interest rates. We estimate that a hypothetical 100-basis point change in market 
interest rates would impact the fair value of our investment portfolio as of December 31, 2021 by $0.1 million. 
We contract with contract research organizations and manufacturers globally. Transactions with these providers are 
predominantly settled in U.S. dollars and, therefore, we believe that we have only minimal exposure to foreign 
currency exchange risks. We do not hedge against foreign currency risks. 
Item 8. Financial Statements and Supplementary Data 
The information required by this item may be found on pages F-2 through F-32 as listed below, including the 
quarterly information required by this item. 

113
INDEX 
 
Page
Report of Independent Registered Public Accounting Firm (PCAOB ID: 42) ..................................................
F-2
Consolidated Balance Sheets ..............................................................................................................................
F-4
Consolidated Statements of Operations and Comprehensive Loss ....................................................................
F-5
Consolidated Statements of Cash Flows ............................................................................................................
F-6
Consolidated Statements of Stockholders’ Equity .............................................................................................
F-7
Notes to Consolidated Financial Statements ......................................................................................................
F-8

114
Item 9. Changes in and Disagreements with Accountants on Accounting and Financial Disclosure 
None. 
Item 9A. Controls and Procedures 
Disclosure Controls and Procedures 
Our management, with the participation of our principal executive officer and principal financial officer, evaluated 
the effectiveness of our disclosure controls and procedures (as defined in Rules 13a-15(e) and 15d-15(e) under the 
Securities Exchange Act of 1934, as amended, or the Exchange Act) as of December 31, 2021. In designing and 
evaluating our disclosure controls and procedures, management recognized that any controls and procedures, no 
matter how well designed and operated, can provide only reasonable assurance of achieving their objectives, and our 
management necessarily applied its judgment in evaluating the cost-benefit relationship of possible controls and 
procedures. Based on this evaluation, our principal executive officer and principal financial officer concluded that as 
of December 31, 2021, our disclosure controls and procedures were (1) designed to ensure that material information 
relating to us is made known to our management including our principal executive officer and principal financial 
officer by others, particularly during the period in which this report was prepared and (2) effective, in that they 
provide reasonable assurance that information required to be disclosed by us in the reports we file or submit under 
the Exchange Act is recorded, processed, summarized and reported within the time periods specified in the SEC’s 
rules and forms. 
Management’s Annual Report on Internal Control over Financial Reporting 
Our management is responsible for establishing and maintaining adequate internal control over financial reporting. 
Internal control over financial reporting is defined in Rules 13a-15(f) and 15d-15(f) promulgated under the 
Exchange Act as a process designed by, or under the supervision of, our principal executive and principal financial 
officers and effected by our board of directors, management and other personnel, to provide reasonable assurance 
regarding the reliability of financial reporting and the preparation of financial statements for external purposes in 
accordance with generally accepted accounting principles and includes those policies and procedures that: 

pertain to the maintenance of records that in reasonable detail accurately and fairly reflect the 
transactions and dispositions of the assets of our company; 

provide reasonable assurance that transactions are recorded as necessary to permit preparation of 
financial statements in accordance with generally accepted accounting principles, and that receipts and 
expenditures of our company are being made only in accordance with authorizations of our management 
and directors; and 

provide reasonable assurance regarding prevention or timely detection of unauthorized acquisition, use 
or disposition of our assets that could have a material effect on the financial statements. 
Because of its inherent limitations, internal control over financial reporting may not prevent or detect misstatements. 
Therefore, even those systems determined to be effective can provide only reasonable assurance with respect to 
financial statement preparation and presentation. Projections of any evaluation of effectiveness to future periods are 
subject to the risk that controls may become inadequate because of changes in conditions, or that the degree of 
compliance with the policies or procedures may deteriorate. Our management assessed the effectiveness of our 
internal control over financial reporting as of December 31, 2021. In making this assessment, management used the 
criteria set forth by the Committee of Sponsoring Organizations of the Treadway Commission, or COSO, in Internal 
Control—Integrated Framework (2013). Based on its assessment, management believes that, as of December 31, 
2021, our internal control over financial reporting is effective based on those criteria. 
Ernst & Young LLP, our independent registered public accounting firm has audited the consolidated financial 
statements included in this Annual Report on Form 10-K and, as part of the audit, has issued a report on the 
effectiveness of our internal control over financial reporting as of December 31, 2021, which report is included 
herein.

115
Report of Independent Registered Public Accounting Firm
To the Stockholders and the Board of Directors of Epizyme, Inc. 
Opinion on Internal Control over Financial Reporting
We have audited Epizyme, Inc.’s internal control over financial reporting as of December 31, 2021, based on criteria 
established in Internal Control—Integrated Framework issued by the Committee of Sponsoring Organizations of the 
Treadway Commission (2013 framework) (the COSO criteria). In our opinion, Epizyme, Inc. (the Company) 
maintained, in all material respects, effective internal control over financial reporting as of December 31, 2021, 
based on the COSO criteria.
We also have audited, in accordance with the standards of the Public Company Accounting Oversight Board (United 
States) (PCAOB), the consolidated balance sheets of the Company as of December 31, 2021 and 2020, the related 
consolidated statements of operations and comprehensive loss, stockholders’ equity (deficit) and cash flows for each 
of the three years in the period ended December 31, 2021, and the related notes and our report dated March 1, 2022 
expressed an unqualified opinion thereon.
Basis for Opinion
The Company’s management is responsible for maintaining effective internal control over financial reporting and 
for its assessment of the effectiveness of internal control over financial reporting included in the accompanying 
Management’s Annual Report on Internal Control over Financial Reporting. Our responsibility is to express an 
opinion on the Company’s internal control over financial reporting based on our audit. We are a public accounting 
firm registered with the PCAOB and are required to be independent with respect to the Company in accordance with 
the U.S. federal securities laws and the applicable rules and regulations of the Securities and Exchange Commission 
and the PCAOB.
We conducted our audit in accordance with the standards of the PCAOB. Those standards require that we plan and 
perform the audit to obtain reasonable assurance about whether effective internal control over financial reporting 
was maintained in all material respects. 
Our audit included obtaining an understanding of internal control over financial reporting, assessing the risk that a 
material weakness exists, testing and evaluating the design and operating effectiveness of internal control based on 
the assessed risk, and performing such other procedures as we considered necessary in the circumstances. We 
believe that our audit provides a reasonable basis for our opinion.
Definition and Limitations of Internal Control Over Financial Reporting
A company’s internal control over financial reporting is a process designed to provide reasonable assurance 
regarding the reliability of financial reporting and the preparation of financial statements for external purposes in 
accordance with generally accepted accounting principles. A company’s internal control over financial reporting 
includes those policies and procedures that (1) pertain to the maintenance of records that, in reasonable detail, 
accurately and fairly reflect the transactions and dispositions of the assets of the company; (2) provide reasonable 
assurance that transactions are recorded as necessary to permit preparation of financial statements in accordance 
with generally accepted accounting principles, and that receipts and expenditures of the company are being made 
only in accordance with authorizations of management and directors of the company; and (3) provide reasonable 
assurance regarding prevention or timely detection of unauthorized acquisition, use, or disposition of the company’s 
assets that could have a material effect on the financial statements.
Because of its inherent limitations, internal control over financial reporting may not prevent or detect misstatements. 
Also, projections of any evaluation of effectiveness to future periods are subject to the risk that controls may become 
inadequate because of changes in conditions, or that the degree of compliance with the policies or procedures may 
deteriorate.
/s/ Ernst & Young LLP

116
Boston, Massachusetts 
March 1, 2022
Changes in Internal Control Over Financial Reporting
There were no changes in our internal control over financial reporting (as defined in Rules 13a-15(f) and 15d-15(f) 
under the Exchange Act) during the quarter ended December 31, 2021 that materially affected, or are reasonably 
likely to materially affect, our internal control over financial reporting.
Item 9B. Other Information 
On February 25, 2022, our Board of Directors approved a reduction in our workforce by approximately 12% across 
different areas and functions in the Company. This workforce reduction is expected to be completed by the end of 
the first quarter of 2022.
Affected employees will be offered separation benefits, including severance payments along with temporary 
healthcare coverage assistance. We estimate that the severance and termination-related costs will be approximately 
$2.8 - 3.2 million and we expect to record these charges in the first quarter of 2022. The Company expects that 
payments of these costs will be made through the end of the fourth quarter of 2022.
Item 9C. Disclosure Regarding Foreign Jurisdictions That Prevent Inspections
Not applicable.

117
PART III 
Item 10. Directors, Executive Officers and Corporate Governance 
Information regarding our directors, including the audit committee and audit committee financial experts, and 
executive officers and compliance with Section 16(a) of the Exchange Act will be included in our 2022 Proxy 
Statement and is incorporated herein by reference. 
We have adopted a Code of Business Conduct and Ethics for all of our directors, officers and employees as required 
by NASDAQ governance rules and as defined by applicable SEC rules. Stockholders may locate a copy of our Code 
of Business Conduct and Ethics on our website at www.epizyme.com or request a copy without charge from: 
Epizyme, Inc. 
Attention: Investor Relations 
400 Technology Square, 4th Floor 
Cambridge, MA 02139 
We will post to our website any amendments to the Code of Business Conduct and Ethics, and any waivers that are 
required to be disclosed by the rules of either the SEC or NASDAQ. 
Item 11. Executive Compensation 
The information required by this item regarding executive compensation will be included in our 2022 Proxy 
Statement and is incorporated herein by reference. 
Item 12. Security Ownership of Certain Beneficial Owners and Management and Related Stockholder 
Matters 
The information required by this item regarding security ownership of certain beneficial owners and management 
and securities authorized for issuance under equity compensation plans will be included in our 2022 Proxy 
Statement and is incorporated herein by reference. 
Item 13. Certain Relationships and Related Transactions, and Director Independence 
The information required by this item regarding certain relationships and related transactions and director 
independence will be included in our 2022 Proxy Statement and is incorporated herein by reference. 
Item 14. Principal Accounting Fees and Services 
The information required by this item regarding principal accounting fees and services will be included in our 2022 
Proxy Statement and is incorporated herein by reference. 

118
PART IV 
Item 15. Exhibits, Financial Statement Schedules 
(a)
The following documents are included in this Annual Report on Form 10-K: 
1.
The following Report and Consolidated Financial Statements of the Company are included in this 
Annual Report: 
Report of Independent Registered Public Accounting Firm 
Consolidated Balance Sheets 
Consolidated Statements of Operations and Comprehensive Loss 
Consolidated Statements of Cash Flows 
Consolidated Statements of Stockholders’ Equity 
Notes to Consolidated Financial Statements 
2.
All financial schedules have been omitted because the required information is either presented in 
the consolidated financial statements or the notes thereto or is not applicable or required. 
3.
Exhibits:

119
Exhibit 
Number
 
Description of Exhibit
   3.1
Restated Certificate of Incorporation of the Registrant, as amended (19)
   3.2
Amended and Restated Bylaws of the Registrant (2)
   4.1
Form of Series A Preferred Stock Certificate (15)
   4.2
Certificate of Designation of Series A Convertible Preferred Stock of the Company (15)
   4.3
Description of Securities of the Registrant (18)
 10.1+
2008 Stock Incentive Plan (1)
 10.2+
Form of Incentive Stock Option Agreement under 2008 Stock Incentive Plan (1)
 10.3+
Form of Nonstatutory Stock Option Agreement under 2008 Stock Incentive Plan (1)
 10.4+
Form of Restricted Stock Agreement under 2008 Stock Incentive Plan (1)
 10.5+
2013 Stock Incentive Plan, as amended on March 24, 2020 (16)
 10.6+
Form of Stock Option Agreement under 2013 Stock Incentive Plan (18)
 10.7+
Form of Restricted Stock Agreement under 2013 Stock Incentive Plan (2)
 10.8+
Form of Restricted Stock Unit Agreement under 2013 Stock Incentive Plan (18)
 10.9+
2013 Employee Stock Purchase Plan (2)
 10.10+
Executive Severance and Change in Control Plan (11)
 10.11+
 Form of Restricted Stock Unit Agreement (Inducement Grant) (22)
 10.12+
Form of Restricted Stock Unit Agreement (Inducement Grant) (22)
 10.13+
Employment Offer Letter between the Registrant and Robert Bazemore, dated August 5, 2015 (5)
 10.14+
Employment Offer Letter between the Company and Matthew E. Ros, dated April 15, 2016 (6)
 10.15+
Employment Offer Letter between the Registrant and Paolo Tombesi, dated July 1, 2019 (13) 
 10.16+
Employment Offer Letter between the Company and Shefali Agarwal, dated June 18, 2018 (10)
 10.17+
Employment Offer Letter between the Company and Jeffery Kutok, dated February 21, 2020 (16)
 10.18+
Employment Offer Letter between the Company and Victoria Vakiener, dated October 23, 2018 (17)
 10.19+
Employment Offer Letter between the Company and Grant Bogle, dated August 4, 2021 (22)
 10.20+
Consulting Agreement dated August 4, 2021 between the Company and Robert B. Bazemore (22)
 10.21
Form of Director and Officer Indemnification Agreement (2)
 10.22☐
Companion Diagnostics Agreement dated as of December 18, 2012 between the Registrant and Eisai 
Co., Ltd. on the one side and Roche Molecular Systems, Inc. on the other side (23)
 10.23☐
First Amendment to the Companion Diagnostics Agreement dated October 23, 2013 between the 
Registrant and Eisai Co. Ltd. on the one side and Roche Molecular Systems, Inc. on the other side 
(23)
 10.24☐
Second Amendment to the Companion Diagnostics Agreement dated November 16, 2015 between 
the Registrant and Eisai Co. Ltd. on the one side and Roche Molecular Systems, Inc. on the other 
side (23)

120
 10.25†
Third Amendment to the Companion Diagnostics Agreement dated March 7, 2018 between the 
Registrant and Eisai Co. Ltd. on the one side and Roche Molecular Systems, Inc. on the other side 
(9)
 10.26
Amended and Restated Letter Agreement dated as of March 12, 2015 by and between the Registrant 
and Eisai Co., Ltd. relating to the Companion Diagnostics Agreement (4)
 10.27☐
Amended and Restated Collaboration and License Agreement dated as of March 12, 2015, by and 
between the Registrant and Eisai Co. Ltd. (17)
 10.28
Lease Agreement dated as of June 15, 2012 between the Registrant and ARE-TECH Square, LLC 
(1)
 10.29+
Non-Employee Director Compensation Program, effective January 1, 2021 (17)
 10.30
First Amendment to Lease Agreement dated as of September 30, 2013 between the Registrant and 
ARE-TECH Square, LLC (3)
 10.31
Second Amendment to Lease Agreement dated as of May 18, 2016 between the Registrant and 
ARE-TECH Square, LLC (7)
 10.32
Third Amendment to Lease Agreement, entered into May 25, 2017 and effective May 18, 2017, by 
and between the Company and ARE-TECH Square, LLC (8)
 10.33
Fourth Amendment to Lease Agreement, entered into May 25, 2017 and effective May 18, 2017, by 
and between the Company and ARE-TECH Square, LLC (8)
 10.34☐
Fourth Amendment to the Companion Diagnostics Agreement dated July 26, 2019 between the 
Registrant and Eisai Co. Ltd. on the one side and Roche Molecular Systems, Inc. and Roche 
Sequencing Solutions, Inc. on the other side. (14)
 10.35
Lease Agreement dated as of August 16, 2019 by and between the Registrant and BMR-Hampshire 
LLC. (14)
 10.36
Amended and Restated Loan Agreement dated as of November 3, 2020 by and among the Registrant 
and BioPharma Credit Investments V (Master) LP, BPCR Limited Partnership and BioPharma 
Credit PLC (17)
 10.37
Guaranty and Security Agreement dated as of November 18, 2019 by and between the Registrant 
and  BioPharma Credit PLC (15)
 10.38☐
Purchase Agreement dated as of November 4, 2019 by and between the Registrant and RPI Finance 
Trust (15)
 10.39
Warrant Agreement dated as of November 4, 2019 by and between the Registrant and RPI Finance 
Trust (15)
  10.40
Fifth Amendment to Lease Agreement, dated as of August 11, 2021, by and between the Company 
and ARE-TECH Square, LLC (20)
 10.41☐
License Agreement dated August 7, 2021 between the Registrant and Hutchison China MediTech 
Investment Limited (22)
 10.42
Warrant to Purchase Stock, dated August 7, 2021, by and between the Registrant and Hutchison China 
MediTech Investment Limited (21)
 10.43+
Consulting Agreement, dated October 1, 2021, by and between the Registrant and Victoria Vakiener 
(23)
 10.44+
Consulting Agreement, dated October 27, 2021, by and between the Registrant and Matthew Ros (23)
 21.1
Subsidiaries of the Registrant (1)
 23.1
Consent of Ernst & Young LLP (23)

121
 31.1
Certification of Principal Executive Officer pursuant to Rules 13a-14(a) or 15d-14(a) of the 
Securities Exchange Act of 1934, as adopted pursuant to Section 302 of the Sarbanes-Oxley Act of 
2002. (23)
 31.2
Certification of Principal Financial Officer pursuant to Rules 13a-14(a) or 15d-14(a) of the 
Securities Exchange Act of 1934, as adopted pursuant to Section 302 of the Sarbanes-Oxley Act of 
2002. (23)
 32.1
Certifications pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of The 
Sarbanes-Oxley Act of 2002, by Grant Bogle, President and Chief Executive Officer of the 
Company. (23)
101
The following financial statements formatted in XBRL: (i) Consolidated Balance Sheets, (ii) 
Consolidated Statements of Net Income, (iii) Consolidated Statements of Comprehensive Income, 
(iv) Consolidated Statements of Changes in Stockholders’ Equity, (v) Consolidated Statements of 
Cash Flows, and (vi) the Notes to the Consolidated Financial Statements.
101.INS
Inline XBRL Instance Document – the instance document does not appear in the Interactive Data 
File because its XBRL tags are embedded within the Inline XBRL document
101.SCH
Inline XBRL Taxonomy Extension Schema Document
101.CAL
Inline XBRL Taxonomy Extension Calculation Linkbase Document
101.DEF
Inline XBRL Taxonomy Extension Definition Linkbase Document
101.LAB
Inline XBRL Taxonomy Extension Labels Linkbase Document
101.PRE
Inline XBRL Taxonomy Extension Presentation Linkbase Document
104
Cover Page Interactive Data File (embedded within the Inline XBRL document)
+ Management compensatory agreement. 
† Confidential treatment has been granted as to portions of the exhibit. Confidential materials omitted and filed 
separately with the Securities and Exchange Commission. 
☐ Portions of this exhibit have been omitted pursuant to Item 601(b)(10)(iv) of Regulation S-K
(1)
Incorporated by reference to the Registration Statement on Form S-1 (File No. 333-187982) filed with the 
Securities and Exchange Commission on April 18, 2013. 
(2)
Incorporated by reference to the Registration Statement on Form S-1/A (File No. 333-187892) filed with the 
Securities and Exchange Commission on April 26, 2013. 
(3)
Incorporated by reference to the Quarterly Report on Form 10-Q (File No. 001-35945) filed with the 
Securities and Exchange Commission on October 23, 2013. 
(4)
Incorporated by reference to the Registrant’s Current Report on Form 8-K (File No. 001-35945) filed with the 
Securities and Exchange Commission on March 16, 2015. 
(5)
Incorporated by reference to the Registrant’s Current Report on Form 8-K (File No. 001-35945) filed with the 
Securities and Exchange Commission on August 6, 2015. 
(6)
Incorporated by reference to the Registrant’s Current Report on Form 8-K (File No. 001-35945) filed with the 
Securities and Exchange Commission on May 6, 2016. 
(7)
Incorporated by reference to the Quarterly Report on Form 10-Q (File No. 001-35945) filed with the 
Securities and Exchange Commission on August 8, 2016. 
(8)
Incorporated by reference to the Current Report on Form 8-K (File No. 001-35945) filed with the Securities 
and Exchange Commission on May 30, 2017.
(9)
Incorporated by reference to the Quarterly Report on Form 10-Q (File No. 001-35945) filed with the 
Securities and Exchange Commission on May 8, 2018.

122
(10) Incorporated by reference to the Quarterly Report on Form 10-Q (File No. 001-35945) filed with the 
Securities and Exchange Commission on November 2, 2018.
(11) Incorporated by reference to the Annual Report on Form 10-K (File No. 001-35945) filed with the Securities 
and Exchange Commission on February 26, 2019.
(12) Incorporated by reference to the Current Report on Form 8-K (File No. 001-35945) filed with the Securities 
and Exchange Commission on March 7, 2019.
(13) Incorporated by reference to the Quarterly Report on Form 10-Q (File No. 001-35945) filed with the 
Securities and Exchange Commission on August 9, 2019.
(14) Incorporated by reference to the Quarterly Report on Form 10-Q (File No. 001-35945) filed with the 
Securities and Exchange Commission on October 31, 2019.
(15) Incorporated by reference to the Annual Report on Form 10-K (File No. 001-35945) filed with the Securities 
and Exchange Commission on February 27, 2020.
(16) Incorporated by reference to the Quarterly Report on Form 10-Q (File No. 001-35945) filed with the 
Securities and Exchange Commission on May 4, 2020.
(17) Incorporated by reference to the Annual Report on Form 10-K (File No. 001-35945) filed with the Securities 
and Exchange Commission on February 23, 2021.
(18) Incorporated by reference to the Quarterly Report on Form 10-Q (File No. 001-35945) filed with the 
Securities and Exchange Commission on May 6, 2021.
(19) Incorporated by reference to the Quarterly Report on Form 10-Q (File No. 001-35945) filed with the 
Securities and Exchange Commission on August 9, 2021.
(20) Incorporated by reference to the Registrant’s Current Report on Form 8-K (File No. 001-35945) filed with the 
Securities and Exchange Commission on August 16, 2021.
(21) Incorporated by reference to the Registration Statement on Form S-3 (File No. 333-259680) filed with the 
Securities and Exchange Commission on September 21, 2021.
(22) Incorporated by reference to the Registration Statement on Form 10-Q (File No. 001-35945) filed with the 
Securities and Exchange Commission on November 9, 2021. 
(23) Filed with this Annual Report on Form 10-K.

123
Item 16. Form 10-K Summary
Not applicable.

124
SIGNATURES 
Pursuant to the requirements of Section 13 or 15(d) of the Securities Exchange Act of 1934, the registrant has duly 
caused this report to be signed on its behalf by the undersigned, thereunto duly authorized. 
 
Epizyme, Inc.
By:
/s/ Grant Bogle
Grant Bogle
President and Chief Executive Officer
Dated: March 1, 2022 
Pursuant to the requirements of the Securities Exchange Act of 1934, this report has been signed below by the 
following persons on behalf of the registrant and in the capacities and on the dates indicated: 
 
Name
Title
Date
/s/ Grant Bogle
President, Chief Executive Officer, Director
March 1, 2022 
Grant Bogle
(Principal Executive Officer and Principal 
Financial Officer)
/s/ Joseph Beaulieu
Vice President, Corporate Controller and 
Treasurer
March 1, 2022 
Joseph Beaulieu
(Principal Accounting Officer)
/s/ Kenneth Bate
Director
March 1, 2022 
Kenneth Bate
/s/ Roy Beveridge
Director
March 1, 2022 
Roy Beveridge
/s/ Kevin T. Conroy
Director
March 1, 2022 
Kevin T. Conroy
/s/ Michael Giordano
Director
March 1, 2022 
Michael Giordano, M.D.
/s/ Carl Goldfischer
Director
March 1, 2022 
Carl Goldfischer, M.D.
/s/ Pablo Legorreta
Director
March 1, 2022 
Pablo Legorreta
/s/ David M. Mott
Director
March 1, 2022 
David M. Mott
/s/ Victoria Richon
Director
March 1, 2022 
Victoria Richon, Ph.D.
/s/ Carol Stuckley
Director
March 1, 2022 
Carol Stuckley
 

F-1
EPIZYME, INC. 
INDEX TO CONSOLIDATED FINANCIAL STATEMENTS 
 
Report of Independent Registered Public Accounting Firm ................................................................................
F-2
Consolidated Balance Sheets ................................................................................................................................
F-4
Consolidated Statements of Operations and Comprehensive Loss ......................................................................
F-5
Consolidated Statements of Cash Flows ..............................................................................................................
F-6
Consolidated Statements of Stockholders’ Equity (Deficit) ................................................................................
F-7
Notes to Consolidated Financial Statements ......................................................................................................
F-8

F-2
REPORT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM 
To the Stockholders and the Board of Directors of Epizyme, Inc. 
Opinion on the Financial Statements
We have audited the accompanying consolidated balance sheets of Epizyme, Inc. (the Company) as of December 
31, 2021 and 2020, the related consolidated statements of operations and comprehensive loss, stockholders' equity 
(deficit) and cash flows for each of the three years in the period ended December 31, 2021, and the related notes 
(collectively referred to as the “consolidated financial statements”). In our opinion, the consolidated financial 
statements present fairly, in all material respects, the financial position of the Company at December 31, 2021 and 
2020, and the results of its operations and its cash flows for each of the three years in the period ended December 
31, 2021, in conformity with U.S. generally accepted accounting principles.
We also have audited, in accordance with the standards of the Public Company Accounting Oversight Board 
(United States) (PCAOB), the Company's internal control over financial reporting as of December 31, 2021, 
based on criteria established in Internal Control-Integrated Framework issued by the Committee of Sponsoring 
Organizations of the Treadway Commission (2013 framework), and our report dated March 1, 2022 expressed an 
unqualified opinion thereon.
Basis for Opinion
These financial statements are the responsibility of the Company's management. Our responsibility is to express 
an opinion on the Company’s financial statements based on our audits. We are a public accounting firm registered 
with the PCAOB and are required to be independent with respect to the Company in accordance with the U.S. 
federal securities laws and the applicable rules and regulations of the Securities and Exchange Commission and 
the PCAOB.
We conducted our audits in accordance with the standards of the PCAOB. Those standards require that we plan 
and perform the audit to obtain reasonable assurance about whether the financial statements are free of material 
misstatement, whether due to error or fraud. Our audits included performing procedures to assess the risks of 
material misstatement of the financial statements, whether due to error or fraud, and performing procedures that 
respond to those risks. Such procedures included examining, on a test basis, evidence regarding the amounts and 
disclosures in the financial statements. Our audits also included evaluating the accounting principles used and 
significant estimates made by management, as well as evaluating the overall presentation of the financial 
statements. We believe that our audits provide a reasonable basis for our opinion.
Critical Audit Matter
The critical audit matter communicated below is a matter arising from the current period audit of the financial 
statements that was communicated or required to be communicated to the audit committee and that: (1) relates to 
accounts or disclosures that are material to the financial statements and (2) involved our especially challenging, 
subjective or complex judgments. The communication of the critical audit matter does not alter in any way our 
opinion on the consolidated financial statements, taken as a whole, and we are not, by communicating the critical 
audit matter below, providing a separate opinion on the critical audit matter or on the accounts or disclosures to 
which it relates.

F-3
Accrued and Prepaid Clinical Trial Expenses
Description of 
the Matter
The Company’s total accrued expenses were $30.8 million at December 31, 2021, which 
included the estimated obligation for clinical trial expenses incurred as of December 31, 2021 
but not paid as of that date. In addition, the Company’s total prepaid expenses and other current 
assets were $19.5 million, which included amounts that were paid in advance of services 
incurred pursuant to clinical trials. As discussed in Note 2 to the consolidated financial 
statements, when vendors billing terms do not coincide with the Company’s period-end, the 
Company is required to make estimates of its obligations to those vendors, including clinical 
trial and pharmaceutical development costs, contractual services costs and costs for supply of 
its product candidates incurred in a given accounting period and record accruals at the end of 
the period. The Company bases its estimates on its knowledge of the research and development 
programs, services performed for the period, past history for related activities and the expected 
duration of the vendor service contract, where applicable. Payments for these activities are 
based on the terms of the individual arrangements and may result in payment terms that differ 
from the pattern of costs incurred. There may be instances in which payments made to vendors 
will exceed the level of services provided and result in a prepayment of the clinical expense. 
Auditing the Company’s accrued and prepaid clinical trial expenses is especially challenging 
due to the large volume of information received from multiple vendors that perform service on 
the Company’s behalf. While the Company’s estimates of accrued and prepaid clinical trial 
expenses are primarily based on information received related to each study from its vendors, the 
Company may need to make an estimate for additional costs incurred. Additionally, due to the 
long duration of clinical trials and the timing of invoicing received from vendors, the actual 
amounts incurred are not typically known at the time the financial statements are issued. 
How We 
Addressed the 
Matter in Our 
Audit
We evaluated and tested the design and operating effectiveness of internal controls over the 
Company’s process used in determining the valuation and completeness of accrued and prepaid 
clinical trial expenses.
To evaluate the accrued and prepaid clinical trial expenses, our audit procedures included, 
among others, testing the accuracy and completeness of the underlying data used in determining 
the accrued and prepaid clinical trial expenses and evaluating the assumptions/estimates used 
by management to adjust the actual information received. To assess the nature and extent of the 
services incurred, we corroborated the progress of clinical trials with the Company’s research 
and development personnel that oversee the clinical trials and obtained information directly 
from vendors of their costs incurred to date. To evaluate the completeness and valuation of the 
accrual, we also tested subsequent invoices received and inspected the Company’s contracts 
with vendors and any pending change orders to assess the impact to the accrual.
/s/ Ernst & Young LLP
We have served as the Company’s auditor since 2009.
Boston, Massachusetts
March 1, 2022

F-4
EPIZYME, INC. 
CONSOLIDATED BALANCE SHEETS 
(Amounts in thousands except per share data) 
 
December 31,
2021
December 31,
2020
ASSETS
Current assets:
Cash and cash equivalents
$
98,336
$
168,215
Marketable securities
78,454
205,391
Accounts receivable, net
6,572
3,105
Inventory
3,216
10,461
Prepaid expenses and other current assets
19,465
17,921
Total current assets
206,043
405,093
Property and equipment, net
1,545
2,152
Operating lease assets
20,054
17,305
Intangible assets, net
42,849
47,002
Restricted cash and other assets
18,509
2,021
Total assets
$
289,000
$
473,573
LIABILITIES AND STOCKHOLDERS’ EQUITY
Current liabilities:
Accounts payable
$
10,265
$
10,163
Accrued expenses
30,777
28,572
Current portion of operating lease obligation
4,154
4,665
Total current liabilities
45,196
43,400
Operating lease obligation, net of current portion
18,497
15,409
Deferred revenue
11,950
—
Related party long-term debt, net of debt discount
216,461
215,670
Other long-term liabilities
-
21
Related party liability related to sale of future royalties, net of current portion
15,654
14,176
Warrants to purchase common stock
1,930
—
Commitments and contingencies
Stockholders’ equity (deficit):
Preferred stock, $0.0001 par value; 5,000 shares authorized; 338 shares and 
338 shares issued and outstanding, respectively (equivalent to 3,378 shares 
and 3,378 shares of common stock, respectively, upon conversion at a 10:1 
ratio)
36,127
36,127
Common stock, $0.0001 par value; 150,000 shares and 125,000 shares, 
respectively, authorized; 106,098 shares and 101,627 shares
 issued and outstanding, respectively
11
10
Additional paid-in capital
1,183,006
1,137,470
Accumulated other comprehensive loss
3
3
Accumulated deficit
(1,239,835)
(988,713)
Total stockholders’ equity (deficit)
(20,688)
184,897
Total liabilities and stockholders’ equity (deficit)
$
289,000
$
473,573
See notes to consolidated financial statements. 

F-5
EPIZYME, INC. 
CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS 
(Amounts in thousands except per share data) 
 
Year Ended December 31,
2021
2020
2019
Revenue:
Product revenue, net
$
30,922
$
11,469
$
—
Collaboration and other revenue
6,505
4,293
23,800
Total revenue
37,427
15,762
23,800
Operating expenses:
Cost of revenue
10,498
5,067
—
Research and development
130,966
110,933
132,639
Selling, general and administrative
133,955
125,178
68,303
Total operating expenses
275,419
241,178
200,942
Operating loss
(237,992)
(225,416)
(177,142)
Other (expense) income, net:
Interest (expense) income, net
(22,380)
(4,682)
7,110
Other expense, net
(66)
(99)
(13)
Change in fair value of warrants to purchase common stock
11,120
—
—
Related party non-cash interest expense related to sale of future 
royalties
(1,782)
(1,383)
(192)
Other (expense) income, net
(13,108)
(6,164)
6,905
Loss before income taxes
(251,100)
(231,580)
(170,237)
Income tax provision
(22)
(114)
(58)
Net loss
$ (251,122)
$ (231,694)
$ (170,295)
Other comprehensive (loss) income:
Unrealized gain (loss) on available for sale securities
—
(16)
73
Comprehensive loss
$ (251,122)
$ (231,710)
$ (170,222)
Reconciliation of net loss to net loss attributable to common 
stockholders:
Net loss
$ (251,122)
$ (231,694)
$ (170,295)
Accretion of convertible preferred stock
—
—
(2,940)
Net loss attributable to common stockholders
$ (251,122)
$ (231,694)
$ (173,235)
Net loss per share attributable to common stockholders:
Basic
$
(2.45)
$
(2.29)
$
(1.93)
Diluted
$
(2.45)
$
(2.29)
$
(1.93)
Weighted-average common shares outstanding used in net loss per 
share attributable to common stockholders:
Basic
102,646
100,960
89,891
Diluted
102,646
100,960
89,891
See notes to consolidated financial statements. 

F-6
EPIZYME, INC.
CONSOLIDATED STATEMENTS OF CASH FLOWS 
(Amounts in thousands) 
Year Ended December 31,
2021
2020
2019
CASH FLOWS FROM OPERATING ACTIVITIES:
Net loss
$
(251,122)
$
(231,694)
$
(170,295)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization
5,246
3,984
840
Stock-based compensation
26,787
27,609
18,016
Amortization of discount (premium) on investments
970
(93)
(3,175)
Amortization of debt discount
791
406
37
Change in fair value of warrant liability
(11,120)
-
—
Loss on disposal of property and equipment
-
19
—
Non-cash royalty revenue related to sale of future royalties
(31)
Non-cash interest expense associated with the sale of future royalties
1,782
1,383
192
Deferred income taxes
—
92
92
Changes in operating assets and liabilities:
Accounts receivable
(3,467)
(538)
17,500
Inventory
(8,224)
(10,461)
—
Prepaid expenses and other current assets
(1,605)
(2,398)
(3,359)
Accounts payable
84
1,480
3,389
Accrued expenses
1,771
6,006
2,897
Deferred revenue
11,950
(3,806)
(13,300)
Operating lease assets
(2,749)
3,901
(9,921)
Operating lease liabilities
2,577
(2,085)
10,043
Other assets and liabilities
(493)
(141)
(124)
Net cash used in operating activities
(226,853)
(206,336)
(147,168)
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of available-for-sale securities
(262,613)
(276,404)
(504,981)
Maturities of available-for-sale securities
388,581
312,694
420,255
Purchase of intangible asset
(50,000)
—
Purchases of property and equipment
(486)
(880)
(594)
Net cash provided by (used in) investing activities
125,482
(14,590)
(85,320)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from issuance of common stock, net of commissions
15,954
-
122,991
Proceeds from issuance of preferred stock, net of commissions
—
-
37,432
Payment of offering costs
(308)
(79)
(284)
Proceeds from the issuance of debt
—
195,000
25,000
Proceeds from the issuance of warrants
13,050
Payment of debt issuance costs
—
(3,123)
(1,650)
Proceeds from the issuance of common stock, warrants, and sale of future 
royalties to RPI, net of offering costs
—
—
99,774
Proceeds from the issuance of common stock in connection with the exercise 
of the Put Option, net of financing costs
—
49,915
—
Payment under capital lease obligation
—
—
(16)
Proceeds from stock options exercised
916
6,692
2,358
Issuance of shares under employee stock purchase plan
1,880
1,254
741
Net cash provided by financing activities
31,492
249,659
286,346
Net increase (decrease) in cash, cash equivalents and restricted cash
(69,879)
28,733
53,858
Cash, cash equivalents, and restricted cash, beginning of period
169,724
140,991
87,133
Cash, cash equivalents, and restricted cash, end of period
$
99,845
$
169,724
$
140,991
SUPPLEMENTAL CASH FLOW INFORMATION:
Unpaid offering costs
$
179
$
—
$
78
Unpaid debt issuance costs
$
—
$
—
$
78
Interest paid
$
21,748
$
7,461
$
—
Property and equipment included in accounts payable or accruals
$
—
$
60
$
454
Cash paid for income taxes
$
104
$
64
$
45
See notes to consolidated financial statements

EPIZYME, INC.
CONSOLIDATED STATEMENTS OF STOCKHOLDERS’ EQUITY (DEFICIT)
(Amounts in thousands except share data) 
Common Stock
Preferred Stock
Additional
Paid-In
Accumulated
Accumulated
Other
Comprehensive
Total
Stockholders’
Shares
Amount
Shares
Amount
Capital
Deficit
Loss
Equity (Deficit)
Balance at December 31, 2018
79,175,380
$
8
—
$
—
$
819,779
$
(586,724)
$
(54)
$
233,009
Issuance of series A convertible preferred stock, net of 
commissions and beneficial conversion charge
—
—
350,000
34,492
2,940
—
37,432
Accretion of series A convertible preferred stock
—
—
—
2,940
(2,940)
—
—
—
Issuance of common stock (net of commissions and offering 
costs of $284)
11,500,000
1
—
—
122,707
—
—
122,708
Issuance of common stock to Royalty Pharma (net of 
commissions and offering costs of $304)
6,666,667
1
—
—
78,704
—
—
78,705
Issuance of warrant to Royalty Pharma
—
—
—
—
8,390
—
—
8,390
Exercise of stock options and vesting of restricted stock units
356,538
—
—
—
2,358
—
—
2,358
Stock-based compensation
—
—
—
—
17,875
—
—
17,875
Issuance of shares of common stock in lieu of board fees
12,156
—
—
—
141
—
—
141
Issuance of shares under employee stock purchase plan
72,735
—
—
—
741
—
—
741
Unrealized gain on available for sale securities
—
—
—
—
—
—
73
73
Net loss
—
—
—
—
—
(170,295)
—
(170,295)
Balance at December 31, 2019
97,783,476
$
10
350,000
$
37,432
$
1,050,695
$
(757,019)
$
19
$
331,137
Issuance of common stock in connection with the exercise of 
the Put Option (net of financing costs of $85)
2,500,000
—
—
—
49,915
—
49,915
Issuance of common stock in connection with the conversion of 
series A convertible preferred stock
122,000
—
(12,200)
(1,305)
1,305
—
—
—
Exercise of stock options and vesting of restricted stock units
1,097,280
—
—
—
6,692
—
—
6,692
Stock-based compensation
—
—
—
—
27,471
—
—
27,471
Issuance of shares of common stock in lieu of board fees
8,683
—
—
—
138
—
—
138
Issuance of shares under employee stock purchase plan
115,631
—
—
—
1,254
—
—
1,254
Unrealized loss on available for sale securities
—
—
—
—
—
—
(16)
(16)
Net loss
—
—
—
—
—
(231,694)
—
(231,694)
Balance at December 31, 2020
101,627,070
$
10
337,800
$
36,127
$
1,137,470
$
(988,713)
$
3
$
184,897
Issuance of common stock (net of commissions and offering 
costs of $515)
3,840,977
1
—
—
15,953
—
—
15,954
Exercise of stock options and vesting of restricted stock units
290,872
—
—
—
916
—
—
916
Stock-based compensation
—
—
—
26,597
—
—
26,597
Issuance of shares of common stock in lieu of board fees
35,365
—
—
—
190
—
—
190
Issuance of shares under employee stock purchase plan
303,244
—
—
—
1,880
—
—
1,880
Unrealized loss on available for sale securities
—
—
—
—
—
—
—
—
Net loss
—
—
—
—
—
(251,122)
—
(251,122)
Balance at December 31, 2021
106,097,528
$
11
337,800
$
36,127
$
1,183,006
$
(1,239,835)
$
3
$
(20,688)
See notes to consolidated financial statements. 
F-7

F-8
EPIZYME, INC.
NOTES TO CONSOLIDATED FINANCIAL STATEMENTS 
1. The Company 
Epizyme, Inc. (collectively referred to with its wholly owned, controlled subsidiary, Epizyme Securities 
Corporation, as “Epizyme” or the “Company”) is a commercial-stage biopharmaceutical company that is committed 
to rewriting treatment for people with cancer through the discovery, development, and commercialization of novel 
epigenetic medicines. The Company aspires to change the standard of care for patients and physicians by developing 
targeted medicines with fundamentally new mechanisms of action directed at specific causes of hematological 
malignancies and solid tumors.
Through December 31, 2021, in addition to revenues from product sales, the Company has raised, an aggregate of 
$1,568.3 million to fund its operations. This includes $268.8 million of non-equity funding through its collaboration 
agreements, $368.1 million of funding, consisting of $150.0 million in equity funding received through agreements 
with RPI Finance Trust ("RPI"), and $218.1 million in debt financing received through a loan agreement with 
BioPharma Credit Investments V (Master) LP and BPCR Limited Partnership (as transferee of BioPharma Credit 
Investments V (Master) LP’s interest as a lender), ("the Lenders"), $855.4 million from the sale of common stock 
and series A convertible preferred stock in the Company’s public and at-the-market offerings and $76.0 million from 
the sale of redeemable convertible preferred stock in private financings prior to the Company’s initial public 
offering in May 2013. As of December 31, 2021, the Company had $176.8 million in cash, cash equivalents and 
marketable securities.
In 2020, the Company’s EZH2 inhibitor, tazemetostat, was approved in the United States as TAZVERIK for the 
treatment of epithelioid sarcoma ("ES") and follicular lymphoma ("FL"). Commercial sales of TAZVERIK for the 
treatment of ES commenced in the first quarter of 2020 and commercial sales of TAZVERIK for the treatment of FL 
commenced in the second quarter of 2020. 
The Company commenced active operations in early 2008. Since its inception, the Company has generated an 
accumulated deficit of $1,239.8 million through December 31, 2021 and will require substantial additional capital to 
fund its research, development, and commercialization efforts. The Company is subject to risks common to 
companies in the biotechnology industry, including, but not limited to, risks of failure of commercialization, clinical 
trials and preclinical studies, the need to obtain additional financing to fund the future development and 
commercialization of tazemetostat and the rest of its pipeline, the need to obtain marketing approval for its product 
candidates, the need to successfully commercialize and gain market acceptance TAZVERIK and of any product 
candidates that may be approved in the future, the impact of the COVID-19 pandemic on the Company’s business, 
results of operations, and financial condition, dependence on key personnel, protection of proprietary technology, 
compliance with government regulations, development by competitors of technological innovations and ability to 
transition from clinical-stage manufacturing to commercial-stage production, marketing and sale of products. 
Operating Cost Reduction
On August 9, 2021, the Company announced a cross-functional reduction of approximately 11% of its then current 
workforce under a cost reduction plan. Affected employees were offered separation benefits, including severance 
payments along with temporary healthcare coverage assistance. The severance and termination-related costs totaled 
approximately $2.0 million, $1.6 million of which were recorded as selling general and administrative expenses and 
$0.4 million of which was recorded as research and development expenses in the third quarter of 2021. The 
Company expects that payments of these costs will be made through August 2022.

F-9
2. Summary of Significant Accounting Policies 
Basis of Presentation and Principles of Consolidation 
The consolidated financial statements of the Company included herein have been prepared pursuant to the rules and 
regulations of the Securities and Exchange Commission, or the SEC, and in accordance with U.S. generally accepted 
accounting principles, or GAAP. Any reference in these notes to applicable guidance is meant to refer to the 
authoritative accounting principles generally accepted in the United States as found in the ASC and Accounting 
Standards Update, or ASU, of the Financial Accounting Standards Board, or FASB. The consolidated financial 
statements include the accounts of Epizyme, Inc. and its wholly owned, controlled subsidiary, Epizyme Securities 
Corporation. All intercompany transactions and balances of subsidiaries have been eliminated in consolidation. 
Use of Estimates 
The preparation of these consolidated financial statements in accordance with accounting principles generally 
accepted in the United States requires management to make estimates, judgments and assumptions that affect the 
reported amounts of assets and liabilities and disclosures of contingent assets and liabilities, as of the date of the 
consolidated financial statements, and the reported amounts of revenue and expenses during the reporting period. 
Actual results and outcomes may differ materially from management’s estimates, judgments and assumptions. 
Subsequent Events 
The Company considers events or transactions that occur after the balance sheet date but before the consolidated 
financial statements are issued to provide additional evidence relative to certain estimates or to identify matters that 
require additional disclosure. The Company evaluated all events and transactions through the date these financial 
statements were filed with the Securities and Exchange Commission. 
Cash and cash equivalents 
The Company considers all highly liquid securities with original final maturities of three months or less from the 
date of purchase to be cash equivalents. Cash and cash equivalents are comprised of demand deposit accounts, funds 
in money market accounts, commercial paper and corporate notes. 
Marketable securities 
The Company classifies marketable securities with a remaining maturity when purchased of greater than three 
months as available-for-sale. The Company considers all available-for-sale securities, including those with maturity 
dates beyond 12 months, as available to support current operational liquidity needs and therefore classifies all 
securities with maturity dates beyond 90 days at the date of purchase as current assets. Available-for-sale securities 
are maintained by the Company’s investment managers and may consist of commercial paper, high-grade corporate 
notes, U.S. Treasury securities, and U.S. government agency securities. Available-for-sale securities are carried at 
fair value with the unrealized gains and losses included in other comprehensive loss as a component of stockholders’ 
equity until realized. Any premium or discount arising at purchase is amortized and/or accreted to interest income 
and/or expense over the life of the instrument. Realized gains and losses are determined using the specific 
identification method and are included in other income (expense). 
The aggregate fair value of securities held by the Company in an unrealized loss position for less than twelve 
months as of December 31, 2021 was $28.6 million, which consisted of 4 commercial paper securities and 6 U.S. 
Treasury securities. There were no marketable securities held by the Company for greater than twelve months as of 
December 31, 2021. The aggregate fair value of securities held by the Company in an unrealized loss position for 
less than twelve months as of December 31, 2020 was $67.7 million, which consisted of 6 commercial paper 
securities, 7 corporate notes securities and 1 U.S. Treasury security. There were no marketable securities held by the 
Company for greater than twelve months as of December 31, 2020. 
The Company does not intend to sell and it is unlikely that the Company will be required to sell the above 
investments before recovery of their amortized cost bases, which may be maturity. The Company determined there 

F-10
was no material change in the credit risk of the above investments, and as a result, the Company determined it did 
not hold any investments with an other-than-temporary impairment as of December 31, 2021 and 2020. The 
Company reviews its portfolio of available-for-sale debt securities, using both quantitative and qualitative factors, to 
determine if declines in fair value below cost have resulted from a credit-related loss or other factors. If the decline 
in fair value is due to credit-related factors, a loss is recognized in net income, whereas if the decline in fair value is 
not due to credit-related factors, the loss is recorded in other comprehensive income (loss).
The following table summarizes the available for sale securities held at December 31, 2021 (in thousands): 
Description
Amortized Cost
Unrealized
Gains
Unrealized
Losses
Fair Value
Commercial paper
$
68,427
$
7
$
(3) $ 68,431
Corporate notes
—
—
—
—
U.S. government agency securities and U.S. 
Treasuries
10,025
—
(1)
10,024
Total
$
78,452
$
7
$
(4) $ 78,455
The following table summarizes the available for sale securities held at December 31, 2020 (in thousands): 
Description
Amortized Cost
Unrealized
Gains
Unrealized
Losses
Fair Value
Commercial paper
$
158,907
$
14
$
(8) $ 158,913
Corporate notes
33,437
3
(7)
33,433
U.S. government agency securities and U.S. 
Treasuries
13,044
1
—
13,045
Total
$
205,388
$
18
$
(15) $ 205,391
Certain short-term debt securities with original maturities of less than 90 days are included in cash and cash 
equivalents within the consolidated balance sheets and are not included in the tables above. 
All marketable securities held at December 31, 2021 and December 31, 2020 have maturities of less than one year. 
The amortized cost of available-for-sale securities is adjusted for amortization of premiums and accretion of 
discounts to maturity. At December 31, 2021, the balance in the Company’s accumulated other comprehensive loss 
was composed mainly of activity related to the Company’s available-for-sale marketable securities. There were no 
realized gains or losses recognized on the sale or maturity of available-for-sale securities during the year ended 
December 31, 2021 and December 31, 2020, respectively, and as a result, the Company did not reclassify any 
amounts out of accumulated other comprehensive loss for the same period. 
Restricted Cash
A reconciliation of cash, cash equivalents, and restricted cash reported within the consolidated balance sheets that 
sum to the total of the same such amounts shown in the consolidated statements of cash flows, is as follows:
December 31,
2021
2020
2019
(In thousands)
Cash and cash equivalents
$
98,336 $ 168,215
$ 139,482
Restricted cash, as part of other assets
1,509
1,509
1509
Total cash, cash equivalents, and restricted cash
  shown in the consolidated statements of cash flows
$
99,845 $ 169,724
$ 140,991
The $1.5 million in restricted cash is comprised of $0.5 million in a letter of credit as a security deposit for the office 
and laboratory lease at Technology Square in Cambridge, Massachusetts and $1.0 million in a letter of credit as a 

F-11
security deposit for the Company’s office lease at Hampshire Street in Cambridge, Massachusetts. The Company 
has recorded cash held to secure these letters of credit as restricted cash in restricted cash and other assets on the 
consolidated balance sheet. The restricted cash is classified as non-current based on the related lease terms. 
Fair Value Measurements 
The FASB Codification Topic 820, Fair Value Measurements and Disclosures, requires the use of valuation 
techniques that are consistent with the market approach, the income approach and/or the cost approach. The market 
approach uses prices and other relevant information generated by market transactions involving identical or 
comparable assets and liabilities. The income approach uses valuation techniques to convert future amounts, such as 
cash flows or earnings, to a single present amount on a discounted basis. The cost approach is based on the amount 
that currently would be required to replace the service capacity of an asset (replacement cost). Valuation techniques 
should be consistently applied. GAAP also establishes a fair value hierarchy which requires an entity to maximize 
the use of observable inputs, where available, and minimize the use of unobservable inputs when measuring fair 
value. The standard describes three levels of inputs that may be used to measure fair value: 
Level 1
Quoted prices in active markets for identical assets or liabilities.
Level 2
Observable inputs other than Level 1 prices, such as quoted prices for similar assets or liabilities; quoted 
prices in markets that are not active; or other inputs that are observable or can be corroborated by observable 
market data for substantially the full term of the assets or liabilities.
Level 3
Unobservable inputs that are supported by little or no market activity and that are significant to the fair 
value of the assets or liabilities.
The Company’s financial instruments as of December 31, 2021 and 2020 consisted primarily of cash and cash 
equivalents, marketable securities and accounts receivable and accounts payable. As of December 31, 2021 and 
December 31, 2020, the Company’s financial assets recognized at fair value consisted of the following: 
Fair Value as of December 31, 2021
Total
Level 1
Level 2
Level 3
(In thousands)
Cash equivalents
$ 88,637 $ 67,209
$
21,428
$
—
Marketable securities:
Commercial paper
68,431
—
68,431
—
Corporate notes
—
—
—
—
U.S. government agency securities and treasuries
10,024
—
10,024
—
Total
$ 167,092 $ 67,209
$
99,883
$
—
Fair Value as of December 31, 2020
Total
Level 1
Level 2
Level 3
(In thousands)
Cash equivalents
$ 163,264 $ 113,505
$
49,759
$
—
Marketable securities:
Commercial paper
158,913
—
158,913
—
Corporate notes
33,433
—
33,433
—
U.S. government agency securities and treasuries
13,045
—
13,045
—
Total
$ 368,655 $ 113,505
$ 255,150
$
—
Cash equivalents and marketable securities have been initially valued at the transaction price and subsequently 
valued, at the end of each reporting period, utilizing third-party pricing services or other market observable data. 
The Company measures its cash equivalents at fair value on a recurring basis, which approximates the net asset 
value per share. The Company classifies some of its cash equivalents within Level 1 of the fair value hierarchy 
because they are valued using observable inputs that reflect quoted prices for identical assets in active markets. The 
Company measures its marketable securities at fair value on a recurring basis and classifies those instruments and 
some cash equivalents within Level 2 of the fair value hierarchy. The pricing services used by management utilize 
industry standard valuation models, including both income and market-based approaches and observable market 

F-12
inputs to determine the fair value of marketable securities and those cash equivalents classified within Level 2 of the 
fair value hierarchy. 
As of December 31, 2021, the fair value of the long-term debt, payable in installments through November 18, 2026, 
approximated its carrying value due to the proximity of the issuance of the Tranche D Loan date to December 31, 
2021 (See Note 13, Long-Term Debt).
Amortization of Debt Discount and Issuance Costs
Long-term debt is initially recorded at its allocated proceeds, net of discounts and deferred costs. Debt discount and 
issuance costs, consisting of legal and other fees directly related to the debt, are offset against initial carrying value 
of the debt and are amortized to interest expense over the estimated life of the debt based on the effective interest 
method.
Liability Related to Sale of Future Royalties
The Company treats the liability related to sale of future royalties as a debt financing, as the Company has 
significant continuing involvement in the generation of the cash flows, to be amortized to interest expense using the 
effective interest rate method over the life of the related royalty stream.
The liability related to sale of future royalties and the related interest expense are based on the Company’s current 
estimates of future royalties expected to be paid over the life of the arrangement. The Company will periodically 
assess the expected royalty payments using a combination of internal projections and forecasts from external 
sources. To the extent the Company’s future estimates of royalty payments are greater or less than previous 
estimates or the estimated timing of such payments is materially different than its previous estimates, the Company 
will adjust its effective interest rate, which is applied prospectively.
For further discussion of the sale of future royalties, refer to Note 12, Sale of Future Royalties.
Going Concern 
At each reporting period, the Company evaluates whether there are conditions or events that raise substantial doubt 
about the Company’s ability to continue as a going concern within one year after the date that the financial 
statements are issued. The Company is required to make certain additional disclosures if it concludes substantial 
doubt exists about the Company's ability to continue as a going concern within one year after the date that the 
financial statements are issued and such doubt is not alleviated by the Company’s plans or when its plans alleviate 
substantial doubt about the Company’s ability to continue as a going concern. The Company’s evaluation entails 
analyzing prospective operating budgets and forecasts for expectations of the Company’s cash needs, and comparing 
those needs to its available cash, cash equivalents and marketable securities.
The Company has recurring losses and expects to have recurring losses for the foreseeable future with the continued 
commercialization of TAZVERIK in ES and FL, the development of tazemetostat in other indications, and the 
development of the Company’s other product candidates. In addition, the Company has experienced and continues 
to experience challenges in the continued commercialization of TAZVERIK resulting from the ongoing COVID-19 
pandemic, which the Company believes has had an adverse impact on TAZVERIK revenues. In response to the 
challenges that the Company has continued to face since the Company commenced its launch of TAZVERIK in FL 
in June 2020, the Company implemented an operational cost reduction plan that was announced on August 9, 2021 
and continues to evaluate its costs on an on-going basis with the intent to streamline such costs.
The analysis of the Company’s ability to continue as a going concern for the year ended December 31, 2021 
included consideration of the Company’s current cash needs, including its research and development plans, 
commercialization activities associated with the continued commercialization of TAZVERIK in the ES and FL 
indications, its existing debt service obligations, and anticipated cost savings resulting from its operational cost 
reduction plan, including ongoing efforts to eliminate costs not related to the Company’s strategic focus. The 
analysis included forecasted product revenues from sales of TAZVERIK. Such estimates of future sales contain 
significant judgment as TAZVERIK was first launched in the first half of 2020 and there is little history with which 
to base such estimates. In addition, the Company’s ongoing efforts to eliminate costs not related to the Company’s 
strategic focus contains uncertainties as to whether the Company can attain such benefits. Based on the analysis, the 

F-13
Company concluded that its available cash, cash equivalents and marketable securities as of December 31, 2021 
combined with the $79.5 million raised in January 2022 (see Note 18 for further information) will be sufficient to 
fund current planned operations and capital expenditure requirements and pay its debt service obligations as they 
become due into the third quarter of 2023 which is at least 12 months from the filing date of this Annual Report on 
Form 10-K with the SEC. As a result, the Company concluded that it did not identify conditions or events that raise 
substantial doubt about the Company’s ability to continue as a going concern within one year from the date these 
financial statements were issued. The Company’s current operating plan is based on assumptions that may prove to 
be wrong, and the Company could use its capital resources sooner than it expects, in which case the Company would 
evaluate further reductions in its expenses or obtaining additional financing sooner than it otherwise would, which 
additional financing may not be available or may only be available on terms that are not acceptable to the Company.
Accounts Receivable 
The Company extends credit to customers based on its evaluation of the customer’s financial condition. The 
Company records receivables for all billings when amounts are due under standard terms. Accounts receivable are 
stated at amounts due net of applicable prompt pay discounts and other contractual adjustments as well as an 
allowance for doubtful accounts. The Company assesses the need for an allowance for doubtful accounts by 
considering a number of factors, including the length of time trade accounts receivable are past due, the customer’s 
ability to pay its obligation and the condition of the general economy and the industry as a whole. The Company will 
write off accounts receivable when the Company determines that they are uncollectible. In general, the Company 
has experienced no significant collection issues with its customers. 
Concentration of Credit Risk 
Financial instruments that potentially subject the Company to concentrations of credit risk include cash, cash 
equivalents, marketable securities and accounts receivable. The Company attempts to minimize the risks related to 
cash, cash equivalents and marketable securities by working with highly rated financial institutions that invest in a 
broad and diverse range of financial instruments as defined by the Company. The Company has established 
guidelines relative to credit ratings and maturities intended to safeguard principal balances and maintain liquidity. 
The Company maintains its funds in accordance with its investment policy, which defines allowable investments, 
specifies credit quality standards and is designed to limit the Company’s credit exposure to any single issuer. 
Accounts receivable represent amounts due from customers and collaboration partners. The Company monitors 
economic conditions to identify facts or circumstances that may indicate that any of its accounts receivable are at 
risk of collection. For a further discussion of concentration of credit risk see Note 3, Product Revenue, Net. 
Property and Equipment 
The Company records property and equipment at cost. Property and equipment acquired under a capital lease is 
recorded at the lesser of the present value of the minimum lease payments under the capital lease or the fair value of 
the leased property at lease inception. The Company calculates depreciation and amortization using the straight-line 
method over the following estimated useful lives: 
Asset Category
Useful Lives
Laboratory equipment
3 - 6 years
Computer and office equipment, and furniture
3 - 10 years
Leasehold improvements
3 - 6 years or term of respective lease, if shorter
Amortization of capital lease assets is included in depreciation expense. The Company capitalizes expenditures for 
new property and equipment and improvements to existing facilities and charges the cost of maintenance to expense. 
The Company eliminates the cost of property retired or otherwise disposed of, along with the corresponding 
accumulated depreciation, from the related accounts, and the resulting gain or loss is reflected in the results of 
operations. 

F-14
Impairment of Long-Lived Assets 
The Company reviews long-lived assets to be held and used, including property and equipment and intangible 
assets, for impairment whenever events or changes in circumstances indicate that the carrying amount of the assets 
or asset group may not be recoverable. 
Evaluation of recoverability is based on an estimate of undiscounted future cash flows resulting from the use of the 
asset or asset group and its eventual disposition. In the event that such cash flows are not expected to be sufficient to 
recover the carrying amount of the asset or asset group, the assets are written down to their estimated fair values. No 
such impairments were recorded during 2021, 2020 or 2019. 
Income Taxes 
The Company records deferred income taxes to recognize the effect of temporary differences between tax and 
financial statement reporting. The Company calculates the deferred taxes using enacted tax rates expected to be in 
place when the temporary differences are realized and records a valuation allowance to reduce deferred tax assets if 
it is determined that it is more likely than not that all or a portion of the deferred tax asset will not be realized. The 
Company considers many factors when assessing the likelihood of future realization of deferred tax assets, including 
recent earnings results, expectations of future taxable income, carryforward periods available and other relevant 
factors. The Company records changes in the required valuation allowance in the period that the determination is 
made. 
The Company assesses its income tax positions and records tax benefits for all years subject to examination based 
upon management’s evaluation of the facts, circumstances and information available as of the reporting date. For 
those tax positions where it is more likely than not that a tax benefit will be sustained, the Company records the 
largest amount of tax benefit with a greater than 50.0% likelihood of being realized upon ultimate settlement with a 
taxing authority having full knowledge of all relevant information. For those income tax positions where it is not 
more likely than not that a tax benefit will be sustained, the Company does not recognize a tax benefit in the 
financial statements. The Company records interest and penalties related to uncertain tax positions, if applicable, as 
a component of income tax expense. Refer to Note 8, Income Taxes, for additional information regarding the 
Company’s income taxes. 
Revenue Recognition – Collaboration Revenue
Under ASC 606, Revenue from Contracts with Customers, an entity recognizes revenue when its customer obtains 
control of promised goods or services, in an amount that reflects the consideration which the entity expects to 
receive in exchange for those goods or services. To determine revenue recognition for arrangements that an entity 
determines are within the scope of ASC 606, the entity performs the following five steps: (i) identify the contract(s) 
with a customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price; (iv) 
allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue when (or as) 
the entity satisfies a performance obligation. The Company only applies the five-step model to contracts when it is 
probable that the entity will collect the consideration it is entitled to in exchange for the goods or services it transfers 
to the customer. At contract inception, once the contract is determined to be within the scope of ASC 606, the 
Company assesses the goods or services promised within each contract and determines those that are performance 
obligations, and assesses whether each promised good or service is distinct. The Company then recognizes as 
revenue the amount of the transaction price that is allocated to the respective performance obligation when (or as) 
the performance obligation is satisfied.
 
The Company has entered into collaboration and license agreements, which are within the scope of ASC 606, to 
discover, develop, manufacture and commercialize product candidates. The terms of these agreements typically 
contain multiple promises or obligations, which may include: (i) licenses, or options to obtain licenses, to 
compounds directed to specific targets (referred to as “exclusive licenses”) and (ii) research and development 
activities to be performed on behalf of the collaboration partner related to the licensed targets. Payments to the 
Company under these agreements may include non-refundable license fees, customer option exercise fees, payments 
for research activities, reimbursement of certain costs, payments based upon the achievement of certain milestones 
and royalties on any resulting net product sales.

F-15
The Company first evaluates license and/or collaboration arrangements to determine whether the arrangement (or 
part of the arrangement) represents a collaborative arrangement pursuant to ASC Topic 808, Collaborative 
Arrangements, based on the risks and rewards and activities of the parties pursuant to the contractual arrangement. 
The Company accounts for collaborative arrangements (or elements within the contract that are deemed part of a 
collaborative arrangement), which represent a collaborative relationship and not a customer relationship, outside the 
scope of ASC 606. The Company’s collaborations primarily represent revenue arrangements. The Company uses 
judgment to determine whether milestones or other variable consideration, except for sales-based royalties, should 
be included in the transaction price as described further below. The transaction price is allocated to each 
performance obligation on a relative stand-alone selling price basis, for which the Company recognizes revenue as 
or when the performance obligations under the contract are satisfied. In determining the stand-alone selling price of 
a license to the Company’s proprietary technology or a material right provided by a customer option, the Company 
considers market conditions as well as entity-specific factors, including those factors contemplated in negotiating the 
agreements as well as internally developed estimates that include assumptions related to the market opportunity, 
estimated development costs, probability of success and the time needed to commercialize a product candidate 
pursuant to the license. In validating its estimated stand-alone selling price, the Company evaluates whether changes 
in the key assumptions used to determine its estimated stand-alone selling price will have a significant effect on the 
allocation of arrangement consideration between performance obligations.
Amounts received prior to revenue recognition are recorded as deferred revenue. Amounts expected to be 
recognized as revenue within the 12 months following the balance sheet date are classified as current portion of 
deferred revenue in the accompanying consolidated balance sheets. Amounts not expected to be recognized as 
revenue within the 12 months following the balance sheet date are classified as deferred revenue, net of current 
portion. Amounts recognized as revenue, but not yet received or invoiced are generally recognized as contract 
assets.
Exclusive Licenses – If the license to the Company’s intellectual property is determined to be distinct from the other 
promises or performance obligations identified in the arrangement, which generally include research and 
development services, the Company recognizes revenue from non-refundable, upfront fees allocated to the license 
when the license is transferred to the customer and the customer is able to use and benefit from the license. In 
assessing whether a license is distinct from the other promises, the Company considers relevant facts and 
circumstances of each arrangement, including the research and development capabilities of the collaboration partner 
and the availability of the associated expertise in the general marketplace. In addition, the Company considers 
whether the collaboration partner can benefit from the license for its intended purpose without the receipt of the 
remaining promises, whether the value of the license is dependent on the unsatisfied promises, whether there are 
other vendors that could provide the remaining promises, and whether it is separately identifiable from the 
remaining promises. For licenses that are combined with other promises, the Company utilizes judgment to assess 
the nature of the combined performance obligation to determine whether the combined performance obligation is 
satisfied over time or at a point in time and, if over time, the appropriate method of measuring progress for purposes 
of recognizing revenue. The Company evaluates the measure of progress each reporting period and, if necessary, 
adjusts the measure of performance and related revenue recognition. The measure of progress, and thereby periods 
over which revenue should be recognized, are subject to estimates by management and may change over the course 
of the research and development and licensing agreement.
 

F-16
Research and Development Services – The promises under the Company’s collaboration and license agreements 
generally include research and development services to be performed by the Company on behalf of the collaboration 
partner. For performance obligations that include research and development services, the Company generally 
recognizes revenue allocated to such performance obligations based on an appropriate measure of progress. The 
Company utilizes judgment to determine the appropriate method of measuring progress for purposes of recognizing 
revenue, which is generally an input measure such as costs incurred. The Company evaluates the measure of 
progress each reporting period as described under Exclusive Licenses above. Reimbursements from the partner that 
are the result of a collaborative relationship with the partner, instead of a customer relationship, such as co-
development activities, are recorded as a reduction to research and development expense.
Customer Options – The Company’s arrangements may provide a collaborator with the right to select a target for 
licensing either at the inception of the arrangement or within an initial pre-defined selection period, which may, in 
certain cases, include the right of the collaborator to extend the selection period. Under these agreements, fees may 
be due to the Company (i) at the inception of the arrangement as an upfront fee or payment, (ii) upon the exercise of 
an option to acquire a license or (iii) upon extending the selection period as an extension fee or payment. If an 
arrangement is determined to contain customer options that allow the customer to acquire additional goods or 
services, the goods and services underlying the customer options are not considered to be performance obligations at 
the outset of the arrangement, as they are contingent upon option exercise. The Company evaluates the customer 
options for material rights, or options to acquire additional goods or services for free or at a discount. If the customer 
options are determined to represent a material right, the material right is recognized as a separate performance 
obligation at the inception of the arrangement. The Company allocates the transaction price to material rights based 
on the relative stand-alone selling price, which is determined based on the identified discount and the probability 
that the customer will exercise the option. Amounts allocated to a material right are not recognized as revenue until, 
at the earliest, the option is exercised or expires.
Milestone Payments – At the inception of each arrangement that includes development milestone payments, the 
Company evaluates whether the milestones are considered probable of being achieved and estimates the amount to 
be included in the transaction price using the most likely amount method. If it is probable that a significant revenue 
reversal would not occur, the associated milestone value is included in the transaction price. Milestone payments 
that are not within the control of the Company or the licensee, such as regulatory approvals, are not considered 
probable of being achieved until those approvals are received. The Company evaluates factors such as the scientific, 
clinical, regulatory, commercial, and other risks that must be overcome to achieve the particular milestone in making 
this assessment. There is considerable judgment involved in determining whether it is probable that a significant 
revenue reversal would not occur. At the end of each subsequent reporting period, the Company reevaluates the 
probability of achievement of all milestones subject to constraint and, if necessary, adjusts its estimate of the overall 
transaction price. Any such adjustments are recorded on a cumulative catch-up basis, which would affect revenues 
and earnings in the period of adjustment. If a milestone or other variable consideration relates specifically to the 
Company’s efforts to satisfy a single performance obligation or to a specific outcome from satisfying the 
performance obligation, the Company generally allocates the milestone amount entirely to that performance 
obligation once it is probable that a significant revenue reversal would not occur.
Royalties – For arrangements that include sales-based royalties, including milestone payments based on a level of 
sales, and the license is deemed to be the predominant item to which the royalties relate, the Company recognizes 
revenue at the later of (i) when the related sales occur or (ii) when the performance obligation to which some or all 
of the royalty has been allocated has been satisfied (or partially satisfied). To date, the Company has not recognized 
any royalty revenue resulting from any of its licensing arrangements.
For a complete discussion of accounting for collaboration revenues, see Note 11, Collaborations.
Revenue Recognition – Product Revenue
 
The Company recognizes revenue when a customer obtains control of promised goods or services, in an amount that 
reflects the consideration which the Company expects to receive in exchange for those goods or services. To 
determine revenue recognition, the Company performs the following five steps: (i) identify the contract(s) with a 

F-17
customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price; (iv) allocate 
the transaction price to the performance obligations in the contract; and (v) recognize revenue when (or as) the 
Company satisfies a performance obligation. The Company only applies the five-step model to contracts when it is 
probable that the Company will collect the consideration it is entitled to in exchange for the goods or services it 
transfers to the customer. For a further discussion of accounting for net product revenue see Note 3, Product 
Revenue, Net.
Revenue Recognition – Other Revenue
Other revenue consists of revenue from the sales of tazemetostat active pharmaceutical ingredient (API) and drug 
product to the Company’s licensees or collaborators. The Company recognizes revenue on tazemetostat API and 
drug product when control has transferred under the terms of each agreement.
Cost of Revenues
Cost of revenues primarily consists of costs related to the sales of TAZVERIK and sales of tazemetostat API and 
drug product to the Company’s licensees or collaborators. These costs include materials, labor, manufacturing 
overhead, amortization of milestone payments, and royalties payable on net sales of TAZVERIK. Cost of revenues 
for the year ended December 31, 2021 included approximately $0.8 million related to sales of tazemetostat drug 
product. There were no cost of revenues for the sales of tazemetostat drug product during the year ended December 
31, 2020 and 2019. 
Research and Development Expenses 
Research and development expenses are expensed as incurred. Research and development expenses are comprised 
of costs incurred in providing research and development activities, including salaries and benefits, facilities costs, 
overhead costs, contract research and development services, and other outside costs. Nonrefundable advance 
payments for goods and services that will be used in future research and development activities are expensed when 
the activity has been performed or when the goods have been received rather than when the payment is made. 
External research and development expenses associated with the Company’s programs include clinical trial site 
costs, clinical manufacturing costs, costs incurred for consultants and other outside services, such as data 
management and statistical analysis support, and materials and supplies used in support of the clinical and 
preclinical programs. Internal costs of the Company’s clinical programs include salaries, stock-based compensation, 
and the portion of the Company’s facility costs allocated to research and development expense. When vendors 
billing terms do not coincide with the Company’s period-end, the Company is required to make estimates of its 
obligations to those vendors, including clinical trial and pharmaceutical development costs, contractual services 
costs and costs for supply of its product candidates incurred in a given accounting period and record accruals at the 
end of the period. The Company bases its estimates on its knowledge of the research and development programs, 
services performed for the period, past history for related activities and the expected duration of the vendor service 
contract, where applicable. 
The Company generally accrues expenses related to research and development activities based on the services 
received and efforts expended pursuant to contracts with multiple contract research organizations that conduct and 
manage clinical trials, as well as other vendors that provide research and development services. Payments for these 
activities are based on the terms of the individual arrangements and may result in payment terms that differ from the 
pattern of costs incurred. There may be instances in which payments made to vendors will exceed the level of 
services provided and result in a prepayment of the clinical expense. Payments under some of these contracts depend 
on factors such as the successful enrollment of subjects and the completion of clinical trial milestones. In accruing 
service fees, the Company estimates the time period over which services will be performed and the level of effort to 
be expended in each period. If the actual timing of the performance of services or the level of effort varies from 
estimates, the Company would adjust the accrual or prepaid accordingly in future periods. 

F-18
Stock-Based Compensation 
The Company measures employee and non-employee stock-based compensation based on the grant date fair value 
of the stock-based compensation award. The Company grants stock options at exercise prices equal to the fair value 
of the Company’s common stock on the date of grant, based on observable market prices. 
The Company recognizes employee stock-based compensation expense on a straight-line basis over the requisite 
service period of the awards. The Company recognizes forfeitures at the time they occur. The actual expense 
recognized over the vesting period will only represent those options that vest. 
For awards with performance conditions in which the award does not vest unless the performance condition is met, 
the Company recognizes expense if, and to the extent that, the Company estimates that achievement of the 
performance condition is probable. If the Company concludes that vesting is probable, it recognizes expense from 
the date it reaches this conclusion through the estimated vesting date. For awards with performance conditions that 
accelerate vesting of the award, the Company estimates the likelihood of satisfaction of the performance conditions, 
which affects the period over which the expense is recognized, and recognizes the expense using the accelerated 
attribution model.
Refer to Note 15, Employee Benefit Plans, for additional information regarding the measurement and recognition of 
expense related to the Company’s stock-based compensation awards. 
Earnings (Loss) per Share 
The Company computes basic earnings (loss) per share by dividing income (loss) attributable to common 
stockholders by the weighted average number of shares of common stock outstanding. During periods of income, 
the Company allocates participating securities a proportional share of income determined by dividing total weighted 
average participating securities by the sum of the total weighted average common shares and participating securities 
(the “two-class method”). The Company’s restricted stock and Series A Convertible Preferred Stock par value of 
$0.0001 per share (the “Series A Preferred Stock”) participate in dividends declared by the Company and are 
therefore considered to be participating securities. Participating securities have the effect of diluting both basic and 
diluted earnings per share during periods of income. During periods of loss, the Company allocates no loss to 
participating securities because they have no contractual obligation to share in the losses of the Company. The 
Company computes diluted earnings (loss) per share after giving consideration to the dilutive effect of stock options 
and warrants that are outstanding during the period, except where such non-participating securities would be anti-
dilutive. Refer to Note 16, Loss per Share, for the Company’s calculation of loss per share for the periods presented.
Segment Information 
The Company currently operates as one reportable business segment: the discovery, development, and 
commercialization of novel epigenetic therapies for patients with cancer. 
Inventory 
The Company outsources the manufacturing of TAZVERIK and uses contract manufacturers to produce the raw and 
intermediate materials used in the production of TAZVERIK as well as the finished product. The Company 
currently has one supplier qualified for each step in the manufacturing process and is in the process of qualifying 
additional suppliers. 
Inventory is composed of raw materials, intermediate materials, which are classified as work-in-process, and 
finished goods, which are goods that are available for sale. The Company states inventory at the lower of cost or net 
realizable value with the cost based on the first-in, first-out method. Inventory is classified as long-term when it is 
expected to be utilized beyond the Company’s normal operating cycle and is included in restricted cash and other 
assets on the Company's condensed consolidated balance sheets. If the Company identifies excess, obsolete or 
unsalable items, it writes down its inventory to its net realizable value in the period in which the impairment is 
identified. These adjustments are recorded based upon various factors related to the product, including the level of 
product manufactured by the Company, the level of product in the distribution channel, current and projected 
demand, the expected shelf-life of the product and firm inventory purchase commitments. Shipping and handling 

F-19
costs incurred for inventory purchases are included in inventory costs and costs incurred for product shipments are 
recorded as incurred in cost of revenue.
Prior to receiving its first approval from the U.S. Food and Drug Administration, or FDA, on January 23, 2020 to 
sell TAZVERIK, the Company expensed all costs incurred related to the manufacture of TAZVERIK as research 
and development expense because of the inherent risks associated with the development of a product candidate, the 
uncertainty about the regulatory approval process and the lack of history for the Company of regulatory approval of 
drug candidates.
Intangible Assets, Net
Intangible assets consist of capitalized milestone payments made to third parties under an in-license of patent rights 
upon receiving regulatory approval of TAZVERIK. The finite lived intangible assets are being amortized on a 
straight-line basis over the expected time period the Company will benefit from the in-licensed rights, which is 
generally the patent life. Intangible assets are recorded at cost at the time of their acquisition and are stated in the 
Company’s consolidated balance sheets net of accumulated amortization and impairments, if applicable. The 
amortization expense is recognized as cost of revenue in the Company’s consolidated statement of operations. 
During 2020 the Company paid a total of $50.0 million in milestone payments under its agreement with Eisai, Co., 
Ltd., or Eisai, upon regulatory approval of tazemetostat for ES and FL. These regulatory milestones have been 
capitalized as intangible assets. 
The following table presents intangible assets as of December 31, 2021 (in thousands):
December 31,
2021
December 31,
2020
Estimated 
useful
life (years)
In-licensed rights
$
50,000
$
50,000
12.2
Less: accumulated amortization
(7,151)
(2,998)
Total intangible asset, net
$
42,849
$
47,002
The Company recorded approximately $4.2 million and $3.0 million in amortization expense related to intangible 
assets, using the straight-line methodology, during the years ended December 31, 2021 and 2020, respectively. 
Estimated future amortization expense for intangible assets is approximately $4.2 million per year thereafter.
The Company assesses its intangible assets for impairment if indicators are present or changes in circumstance 
suggest that impairment may exist. Events that could result in an impairment, or trigger an interim impairment 
assessment, include the receipt of additional clinical or nonclinical data regarding one of the Company’s drug 
candidates or a potentially competitive drug candidate, changes in the clinical development program for a drug 
candidate, or new information regarding potential sales for the drug. If impairment indicators are present or changes 
in circumstance suggest that impairment may exist, the Company performs a recoverability test by comparing the 
sum of the estimated undiscounted cash flows of each intangible asset to its carrying value on the consolidated 
balance sheet. If the undiscounted cash flows used in the recoverability test are less than the carrying value, the 
Company would determine the fair value of the intangible asset and recognize an impairment loss if the carrying 
value of the intangible asset exceeds its fair value.
During the three months ended June 30, 2021, the Company concluded the lower than anticipated current and 
projected future revenue, due to the impact of the COVID-19 pandemic as well as other factors, was an indicator 
that impairment may exist related to its finite-lived intangible assets. As a result, the Company performed a 
recoverability test and determined that the finite-lived intangible assets were recoverable. The Company’s 
quantitative assessment considered significant assumptions related to estimates of future TAZVERIK sales, offset 
by direct costs to derive the sales. The estimates of future TAZVERIK sales and associated costs include estimates 
of significant growth, however, these estimates are uncertain as the product was first launched in the first half of 
2020 and due to the uncertainties associated with the ongoing COVID-19 pandemic. Given the limited history of 
sales and the inherent difficulty in making a long-range forecast, such estimates contain significant uncertainty. If 
the assumptions regarding forecasted revenue or the costs to derive such revenues prove to be inaccurate, the 

F-20
Company may be required to perform future impairment analyses and record an impairment charge for its intangible 
assets in future periods.
Leases
At inception of a contract, we determine whether an arrangement is or contains a lease. For all leases, we determine 
the classification as either operating or financing. As of December 31, 2021, the Company does not have any leases 
that are classified as finance leases. 
ROU assets represent our right to use an underlying asset for the lease term, and lease liabilities represent our 
obligation to make lease payments under the lease. Lease recognition occurs at the commencement date, and lease 
liability amounts are based on the present value of lease payments made during the lease term. Renewals are not 
assumed in the determination of the lease term unless they are deemed to be reasonably assured at the inception of 
the lease. Because our leases do not provide information to determine an implicit interest rate, we use our 
incremental borrowing rate in determining the present value of lease payments. ROU assets also include any lease 
payments made prior to the commencement date less lease incentives received. Operating lease expense is 
recognized on a straight-line basis over the lease term.
The Company has elected not to apply the recognition requirements to short-term leases with a term of 12 months or 
less. Instead, the Company recognizes the lease payments in the consolidated statements of operations and 
comprehensive loss on a straight-line basis over the lease term.
Recently Adopted Accounting Pronouncements 
From time to time, new accounting pronouncements are issued by the FASB or other standard setting bodies that we 
adopt as of the specified effective date. Unless otherwise discussed below, we do not believe that the adoption of 
recently issued standards have or may have a material impact on our consolidated financial statements or 
disclosures.
Revenue Recognition – Collaboration Revenue
In November 2018, the FASB, issued ASU 2018-18, Collaborative Arrangements, or ASC 808, which clarifies that 
certain transactions between collaborative arrangement participants should be accounted for as revenue when the 
collaborative arrangement participant is a customer in the context of a unit of account and precludes recognizing as 
revenue consideration received from a collaborative arrangement participant if the participant is not a customer. The 
new standard was effective in the first quarter of fiscal 2021. The Company adopted ASC 808 effective in the first 
quarter of fiscal 2021 and the Company’s adoption of this standard did not have a material effect on the Company’s 
financial statements.
Income Taxes
In December 2019, the Financial Accounting Standards Board, or the FASB, issued ASU 2019-12, Income Taxes, or 
ASC 740, which simplifies the accounting for income taxes. The new standard was effective in the first quarter of 
fiscal 2021. The Company adopted ASC 740 effective in the first quarter of fiscal 2021 and the Company’s adoption 
of this standard did not have a material effect on the Company’s financial statements.
3. Product Revenue, Net
The Company sells TAZVERIK in the United States principally to a limited number of specialty pharmacies, which 
dispense the product directly to patients, and specialty distributors, which in turn sell the product to hospital 
pharmacies and community practice pharmacies (collectively, healthcare providers) for the treatment of patients. 
The specialty pharmacies and specialty distributors are referred to as the Company’s customers. 
Product revenue is recognized by the Company in an amount that reflects the consideration which the Company 
expects to receive in exchange for those goods or services when the customer obtains control of the product, which 
occurs at a point in time, typically when the product is received by the Company’s customers. The Company 
provides a right of return to its customers for unopened product for a limited time before and after its expiration 

F-21
date, which right of return lapses upon shipment to a patient. Healthcare providers to whom specialty distributors 
sell TAZVERIK hold limited inventory that is designated for patients, and the Company monitors inventory levels 
in the distribution channel, to limit the risk of return.
Reserves for Variable Consideration 
Revenues from product sales are recorded as product revenue at the net sales price (transaction price), which 
includes estimates of variable consideration for which reserves are established and which result from discounts, 
returns, chargebacks, rebates, co-pay assistance and other allowances that are offered within contracts between the 
Company and its customers, health care providers, payors and other indirect customers relating to the Company’s 
product sales. These reserves are based on the amounts earned or to be claimed on the related sales and are classified 
as reductions of accounts receivable (if the amount is payable to the customer) or a current liability (if the amount is 
payable to a party other than a customer). Where appropriate, these estimates take into consideration a range of 
possible outcomes that are probability-weighted for relevant factors such as the Company’s historical experience, 
current contractual and statutory requirements, specific known market events and trends, industry data and 
forecasted customer buying and payment patterns. Overall, these reserves reflect the Company’s best estimates of 
the amount of consideration to which the Company is entitled based on the terms of the contract(s). The amount of 
variable consideration that is included in the transaction price may be constrained, and is included in the net sales 
price only to the extent that it is probable that a significant reversal in the amount of the cumulative revenue 
recognized will not occur in a future period. Actual amounts of consideration ultimately received may differ from 
the Company’s estimates. If actual results in the future vary from the Company’s estimates, the Company will adjust 
these estimates, which would affect net product revenue and earnings in the period such variances become known.
Trade Discounts and Allowances: The Company generally provides customers with discounts that include incentive 
fees that are explicitly stated in customer contracts and are recorded as a reduction of revenue in the period the 
related product revenue is recognized. In addition, the Company receives sales order management, data and 
distribution services from certain customers. To the extent the services received are distinct from the Company’s 
sale of products to the customer, these payments are classified in selling, general and administrative expenses in the 
consolidated statements of operations and comprehensive loss.
Product Returns: Consistent with industry practice, the Company generally offers customers a limited right of return 
based on the product’s expiration date for product that has been purchased from the Company, which lapses upon 
shipment to a patient. The Company estimates the amount of product sales that may be returned by customers and 
records this estimate as a reduction of revenue in the period in which the related product revenue is recognized. The 
Company currently estimates product return liabilities using available industry data and the Company’s own 
historical sales information, including its visibility into the product remaining in the distribution channel.
Provider Chargebacks and Discounts: Chargebacks for fees and discounts to healthcare providers represent the 
estimated obligations resulting from contractual commitments to sell products to qualified healthcare providers at 
prices lower than the list prices charged to customers who directly purchase the product from the Company. 
Customers charge the Company for the difference between what they pay for the product and the ultimate selling 
price to the qualified healthcare providers. These reserves are established in the same period that the related revenue 
is recognized, resulting in a reduction of product revenue and accounts receivable. Chargeback amounts are 
generally determined at the time of resale to the qualified healthcare provider by customers, and the Company 
generally issues credits for such amounts within a few weeks of the customer’s notification to the Company of the 
resale. Reserves for chargebacks consist of credits that the Company expects to issue for units that remain in the 
distribution channel at each reporting period end that the Company expects will be sold to qualified healthcare 
providers, and chargebacks that customers have claimed but for which the Company has not yet issued a credit.
Government Rebates: The Company is subject to discount obligations under state Medicaid programs and Medicare. 
The Company estimates its Medicaid and Medicare rebates based upon a range of possible outcomes that are 
probability-weighted for the estimated payor mix. These reserves are recorded in the same period in which the 
related revenue is recognized, resulting in a reduction of product revenue and the establishment of a current liability 
that is included in accrued expenses on the Company’s consolidated balance sheets. For Medicare, the Company 
also estimates the number of patients in the prescription drug coverage gap for whom the Company will owe an 

F-22
additional liability under the Medicare Part D program. The Company’s liability for these rebates consists of 
invoices received for claims from prior quarters that have not been paid or for which an invoice has not yet been 
received, estimates of claims for the current quarter, and estimated future claims that will be made for product that 
has been recognized as revenue, but remains in the distribution channel inventories at period end.
Payor Rebates: The Company may contract with various private payor organizations, primarily insurance 
companies and pharmacy benefit managers, for the payment of rebates with respect to utilization of the Company’s 
products. The Company estimates these rebates and records such estimates in the same period the related revenue is 
recognized, resulting in a reduction of product revenue and the establishment of a current liability.
Other Incentives/Patient Assistance Programs: The Company also offers voluntary patient assistance programs such 
as co-pay assistance. Co-pay assistance programs are intended to provide financial assistance to qualified 
commercially insured patients with prescription drug co-payments required by payors. The calculation of the accrual 
for co-pay assistance is based on an estimate of claims and the cost per claim that the Company expects to receive 
associated with product that has been recognized as revenue, but remains in the distribution channel inventories at 
period end.
The following table summarizes activity in each of the above product revenue allowances and reserve categories for 
the year ended December 31, 2021:
Chargebacks,
Discounts, and
Government
and Other
Fees
Rebates
Returns
Total
(In thousands)
Balance, January 1, 2021
$
133
$
428
$
67
$
628
Provision
1,886
3,093
274
5,253
Payments or credits
(1,775)
(2,935)
(232)
(4,942)
Balance, December 31, 2021
$
244
$
586
$
109
$
939
The following table summarizes activity in each of the above product revenue allowances and reserve categories for 
the year ended December 31, 2020:
Chargebacks,
Discounts, and
Government
and Other
Fees
Rebates
Returns
Total
(In thousands)
Balance, January 1, 2020
$
—
$
—
$
—
$
—
Provision
802
1,046
67
1,915
Payments or credits
(669)
(618)
—
(1,287)
Balance, December 31, 2020
$
133
$
428
$
67
$
628
Concentration of Credit Risk
Financial instruments which potentially subject the Company to concentrations of credit risk consist of accounts 
receivable from customers and cash held at financial institutions. The Company believes that such customers and 
financial institutions are of high credit quality.

F-23
For the years ended December 31, 2021 and 2020 , net product revenue was primarily generated from five 
individual customers. Revenue earned from each customer as a percentage of net product revenue is as follows:
 
Year Ended December 31,
2021
2020
Customer 1
30%
45%
Customer 2
11%
11%
Customer 3
27%
20%
Customer 4
21%
24%
Customer 5
11%
0%
As of December 31, 2021 and 2020, five individual customers represented as a percentage of accounts receivable as 
follows: 
December 31,
2021
December 31,
2020
Customer 1
15%
21%
Customer 2
10%
14%
Customer 3
22%
29%
Customer 4
29%
36%
Customer 5
24%
0%
No other customer represented more than 10 percent of net product revenue or accounts receivable.
4. Property and Equipment, net 
Property and equipment, net consists of the following: 
 
December 31,
2021
2020
(In thousands)
Laboratory equipment
$
4,580 $
4,435
Computer and office equipment, and furniture
4,386
4,636
Leasehold improvements
453
453
Construction in progress
157
34
Property and equipment
9,576
9,558
Less: accumulated depreciation
(8,031)
(7,406)
Property and equipment, net
$
1,545 $
2,152

F-24
Depreciation expense was $1.1 million, $1.0 million and $0.8 million for the years ended December 31, 2021, 2020, 
and 2019, respectively. 
5. Inventory
All of the Company’s inventory relates to the manufacturing of TAZVERIK. The following table sets forth the 
Company’s inventory as of December 31, 2021 and December 31, 2020:
December 31,
2021
December 31,
2020
(In thousands)
Raw materials
$
3,227
$
1,068
Work in process
13,748
8,564
Finished goods
1,710
829
Total
$
18,685
$
10,461
Balance sheet classification
Inventory
$
3,216
$
10,461
Restricted cash and other assets
15,469
—
Total
$
18,685
$
10,461
As of December 31, 2021, the Company has not capitalized inventory costs related to its other drug development 
programs.
The Company’s active pharmaceutical ingredient has a long shelf life and the Company’s finished drug product has 
a three-year expiry, however the realizability of the inventory is subject to forecasted future sales of TAZVERIK. 
The Company’s forecasted sales currently support the realizability of the Company’s inventory but are uncertain and 
could change in the future, which would require the Company to write down the value of such inventory. Due to the 
revisions to the Company’s forecast of future TAZVERIK sales during the quarter ended June 30, 2021, the 
Company classified a portion of its inventory as long-term.
6. Prepaid Expenses and Other Current Assets 
Prepaid expenses and other current assets consisted of the following: 
 
December 31,
2021
2020
(In thousands)
Prepaid clinical and manufacturing costs
$
12,756 $
12,646
Interest receivable on available for sale securities
72
369
Other prepaid expenses and other receivables
6,637
4,906
Total prepaid expenses and other current assets
$
19,465 $
17,921
7. Accrued Expenses 
Accrued expenses consisted of the following: 
 
December 31,
2021
2020
(In thousands)
Employee compensation and benefits
$ 11,737
$ 11,921
Research and development expenses
13,744
10,664
Current portion of liability related to the sale of future 
royalties
273
—
Professional services and other
5,023
5,987
Accrued expenses
$ 30,777
$ 28,572

F-25
8. Income Taxes 
The Company’s losses before income taxes consist solely of domestic losses. 
The provision for (benefit from) income taxes for the years ended December 31, 2021, 2020, and 2019 is as follows: 
2021
2020
2019
(In thousands)
Current
$
22 $
22
$
(34)
Deferred
—
92
92
Total
22
114
58
Income tax provision
$
22 $
114
$
58
A reconciliation of the federal statutory income tax rate and the Company’s effective income tax rate is as follows: 
Year Ended December 31,
2021
2020
2019
Federal statutory income tax rate
21.0%
21.0%
21.0%
State income taxes
5.5
6.1
6.0
Research and development and other tax credits
2.6
2.0
1.9
Permanent items
0.1
(0.6)
(0.7)
Change in valuation allowance
(27.2)
(27.9)
(27.5)
Other
(2.1)
(0.6)
(0.7)
Effective income tax rate
0.0%
0.0%
0.0%

F-26
Deferred Tax Assets (Liabilities) 
The Company’s deferred tax assets (liabilities) included in other assets in the consolidated balance sheets consist of 
the following: 
December 31,
2021
2020
(In thousands)
Deferred tax assets:
Net operating loss carryforwards
$ 294,248
$ 238,792
Research and development and other credit 
carryforwards
41,189
34,205
Accruals and allowances
3,071
2,949
Eisai license payment
10,752
11,935
Stock compensation
8,211
7,338
Other
1,072
1,220
Sale of royalty
4,210
3,857
Lease liability
5,987
5,462
Business interest
7,060
1,220
Gross deferred tax assets
375,800
306,978
Deferred tax asset valuation allowance
(370,500)
(302,137)
Total deferred tax assets
5,300
4,841
Deferred tax liabilities:
Depreciation and other
—
(18)
Right of use asset
(5,300)
(4,709)
Total deferred tax liabilities
(5,300)
(4,727)
Net deferred tax asset
$
—
$
114
The Company evaluated the expected recoverability of its net deferred tax assets as of December 31, 2021 and 2020, 
and determined that there was insufficient positive evidence to support the recoverability of these net deferred tax 
assets, concluding it is more likely than not that its net deferred tax assets would not be realized in the future; 
therefore, the Company provided a full valuation allowance against its net deferred tax asset balance as of 
December 31, 2021 and 2020.
As of December 31, 2021, the Company had operating loss carryforwards of approximately $1.1 billion and $1.1 
billion available to offset future taxable income for United States federal and state income tax purposes, 
respectively. The U.S. federal tax operating loss carryforwards of $428.5 million will expire at various dates from 
2029 through 2037. Approximately $664.9 million of the U.S. federal tax operating losses can be carried forward 
indefinitely. The state tax operating loss carryforwards expire commencing in 2030. 
Additionally, as of December 31, 2021, the Company had research and development tax credit carryforwards of 
approximately $15.6 million and $6.1 million available to be used as a reduction of federal income taxes and state 
income taxes, respectively, which expire at various dates from 2028 through 2040, as well as federal orphan drug tax 
credit carryforwards of $20.8 million, which would expire at various dates from 2033 through 2041. The Company’s 
ability to use its operating loss carryforwards and tax credits to offset future taxable income is subject to restrictions 
under Section 382 of the U.S. Internal Revenue Code (the “Internal Revenue Code”). These restrictions may limit 
the future use of the operating loss carryforwards and tax credits if certain ownership changes described in the 
Internal Revenue Code occur. Future changes in stock ownership may occur that would create further limitations on 

F-27
the Company’s use of the operating loss carryforwards and tax credits. In such a situation, the Company may be 
required to pay income taxes, even though significant operating loss carryforwards and tax credits exist. 
Uncertain Tax Positions 
The following is a rollforward of the Company’s unrecognized tax benefits: 
December 31,
2021
2020
2019
(In thousands)
Unrecognized tax benefits - as of beginning of 
year
$7,160
$6,328
$ 5,743
Gross increases - current period tax 
positions
1,206
832
585
Unrecognized tax benefits - as of end of year
$8,366
$7,160
$ 6,328
None of the Company’s unrecognized tax benefits would result in income tax expense or impact the Company’s 
effective tax rate if recognized. The Company had no accrued tax-related interest or penalties as of December 31, 
2021 or 2020. 
The Company has generated research and development and orphan drug credits, but has not conducted a study to 
document the qualified activities. This study may result in an adjustment to the Company’s reserve for uncertain tax 
positions, research and development credit, and orphan drug credit carryforwards.
The Company files income tax returns in the U.S. federal tax jurisdiction and various state tax jurisdictions. Since 
the Company is in a loss carryforward position, the Company is generally subject to examination by the U.S. 
federal, state and local income tax authorities for all tax years in which a loss carryforward is available.
9. Commitments and Contingencies 
Commitments 
In addition to commitments under leasing arrangements (Refer to Note 10, Leases), the Company committed to 
$10.4 million of development costs payable to Roche Molecular upon certain development and regulatory 
milestones, under the amended companion diagnostic agreement, and Eisai agreed to reimburse the Company $0.9 
million of this amount related to a regulatory milestone for Japan, which Eisai paid to us in the fourth quarter of 
2020. In July 2019, the Company entered into a fourth amendment to the companion diagnostics agreement. Under 
the amended agreement, the Company and Roche Molecular agreed to divide a $1.0 million regulatory milestone for 
the United States into two separate milestone payments, of which $0.5 million was paid by the Company as part of 
the signed amendment, and the remaining $0.5 million was paid by the Company in December 2019 upon the 
satisfaction of certain conditions set forth in the fourth amendment to the companion diagnostics agreement. As part 
of this fourth amendment, Roche Molecular also assigned all of its rights and obligations under the companion 
diagnostics agreement to Roche Sequencing due to a reorganization at Roche group, and this assignment became 
effective as of January 1, 2020. Through December 31, 2021, the Company has paid Roche Sequencing $9.4 million 
under the amended agreement, including developmental costs of $3.4 million paid in 2020, $4.0 million paid in 2019 
and $2.0 million paid in 2018, respectively, upon the achievement of milestones under the amended agreement with 
Roche Sequencing. As of December 31, 2021, the Company is responsible for the remaining development costs of 
$1.0 million due under the agreement. In addition, the Company paid $1.0 million to Roche Sequencing for the 
achievement of a development milestone in the fourth quarter of 2020. 
Additionally, the Company enters into contracts in the normal course of business with clinical research 
organizations for clinical and preclinical research studies, external manufacturers for product for use in clinical 
trials, and other research supplies and other services as part of the Company’s operations. These contracts generally 

F-28
provide for termination on notice, and therefore are cancelable contracts and not included in contractual 
commitments.
10. Leases 
The Company enters into lease arrangements for its facilities as well as certain equipment. A summary of the 
arrangements are as follows:
Operating Leases
The Company leases office and laboratory space at Technology Square in Cambridge, Massachusetts under a Lease 
Agreement, dated as of June 15, 2012, as amended, or the Technology Square Lease, with ARE-TECH Square, 
LLC, a Delaware limited liability company.
In May 2017, the Company exercised its option to extend the term of the Technology Square Lease to November 30, 
2022. Under the Technology Square Lease as amended, the Company agreed to pay a monthly base rent of 
approximately $0.2 million for the period commencing December 1, 2017 through May 31, 2018, with an increase 
on June 1, 2018 of approximately $33,000 and annual increases of approximately $9,000 on December 1 of each 
subsequent year until the last increase, which will occur on December 1, 2021. 
On August 11, 2021, the Company, entered into a fifth amendment to the Technology Square Lease (the “Fifth 
Amendment”) with ARE-TECH Square, LLC. Under the Fifth Amendment, the Company extended the term of the 
Technology Square Lease through November 30, 2024. Under the Fifth Amendment, the Company will continue to 
pay the Landlord the current monthly base rent amount contemplated by the Technology Square Lease through 
November 30, 2022, with an increase commencing on December 1, 2022 and adjusting the monthly base rent 
amount to approximately $377,000 and an increase commencing on December 1, 2023 and adjusting the monthly 
base rent amount to approximately $388,000 through November 30, 2024. In addition, under the Fifth Amendment, 
the Landlord agreed to provide the Company with a tenant improvement allowance of up to approximately $430,000 
if requested by the Company by August 11, 2022, subject to specified terms and conditions. In accordance with 
ASU 2016-02, Leases, or ASC 842, the Company accounted for the Fifth Amendment as a lease modification and 
remeasured the operating lease liability, resulting in an additional $7.0 million operating lease liability and right of 
use asset. Under the current terms of the Technology Square Lease, the Company does not have any further right to 
extend the term beyond November 30, 2024.
The Company has a $0.5 million letter of credit as a security deposit for the Technology Square Lease and has 
recorded cash held to secure this letter of credit as restricted cash and other assets on the consolidated balance sheet. 
On August 16, 2019, the Company entered into a lease, or the Hampshire Street Lease, with BMR-Hampshire LLC, 
or BMR. The Hampshire Street Lease is for 33,525 rentable square feet of office space in Cambridge, 
Massachusetts. The Hampshire Street Lease commenced as of December 1, 2019. The Hampshire Street Lease has 
an initial term of seven years and four months from the commencement date and provides the Company with an 
option to extend the lease term for one additional five-year period. After a four-month period during which base rent 
was not payable, the Hampshire Street Lease provides for monthly rent payments starting at approximately $0.2 
million and increasing 2.5% per year. In the event that the Company exercises its option to extend the lease term, the 
Hampshire Street Lease provides for monthly rent payments during the additional five-year period at the greater of 
the base rent rate at the end of the initial term or the then-current market rent.
The Company has a $1.0 million letter of credit in favor of BMR as a security deposit for the Hampshire Street 
Lease and has recorded cash held to secure this letter of credit as restricted cash and other assets on the consolidated 
balance sheet. In applying ASC 842, the Company determined the classification of the Hampshire Street Lease to be 
operating and recorded a lease liability and a right-of-use asset as of December 31, 2019.
The Company is required to pay certain variable costs to its landlords in addition to fixed rent. These costs include 
common area maintenance, real estate taxes, and parking and are included in lease expense.

F-29
The following table contains a summary of the lease costs recognized under ASC 842 and other information 
pertaining to the Company’s operating leases for the years ended December 31, 2021, 2020 and 2019:
 
Twelve months 
ended
December 31,
Twelve months 
ended
December 31,
Twelve months 
ended
December 31,
2021
2020
2019
Lease cost
Operating lease cost
$
6,291
$
6,155
$
3,771
Variable lease cost
2,039
1,764
1,318
Total lease cost
$
8,330
$
7,919
$
5,089
Other information
Operating cash flows used for 
operating leases
$
6,436
$
4,374
$
3,648
Weighted average remaining lease 
term
4.2 years
5.3 years
5.3 years
Weighted average discount rate
9.74%
9.77%
9.60%
Future minimum lease payments under the Company’s non-cancelable operating leases as of December 31, 2021, 
are as follows:
2021
(In thousands)
2022
$
6,202
2023
7,517
2024
7,322
2025
3,057
Thereafter
3,909
Total lease payments
$
28,007
Less: imputed interest
(5,356)
Total operating lease liabilities at December 31, 2021
$
22,651
 

F-30
11. Collaborations 
HutchMed
On August 7, 2021, the Company entered into a strategic collaboration pursuant to a license agreement (the 
“HutchMed License Agreement”) with Hutchison China MediTech Investment Limited (“HutchMed”) for the 
development, manufacture and commercialization of tazemetostat, either as a monotherapy or as a part of 
combinations with other therapies, including HutchMed proprietary compounds, agreed by the parties under the 
HutchMed License Agreement (“Licensed Products”) for the treatment of epithelioid sarcoma, follicular lymphoma, 
diffuse large B-cell lymphoma in humans, and any additional indications agreed by the parties in accordance with 
the terms of the HutchMed License Agreement (the “Field”) in mainland China, Taiwan, Hong Kong and Macau 
(each, a “Jurisdiction”, and collectively, the “Territory”).
Agreement Structure
The Company has granted HutchMed licenses under patent rights and know-how controlled by the Company to 
enable HutchMed to develop and commercialize Licensed Products in the Field in the Territory. The licenses 
granted to HutchMed are co-exclusive with the Company with respect to the development of Licensed Products in 
the Field in the Territory and exclusive with respect to the commercialization of Licensed Products in the Field in 
the Territory. The Company also granted HutchMed a license under patent rights and know-how controlled by the 
Company to enable HutchMed to manufacture tazemetostat drug substance and drug product for the purpose of 
developing and commercializing Licensed Products in the Field in the Territory. The Company retains development 
and commercialization rights with respect to Licensed Products in the rest of the world outside of the Territory 
except for Japan. 
The Company has agreed to conduct a technology transfer of manufacturing technology to HutchMed to enable 
HutchMed to manufacture clinical and commercial quantities of tazemetostat drug substance and drug product to 
carry out its obligations and exercise its rights under the HutchMed License Agreement. Subject to the execution of 
a clinical supply agreement or commercial supply agreement, as applicable, and until the completion of the 
technology transfer to HutchMed, the Company has agreed to manufacture and supply HutchMed with tazemetostat 
drug substance and drug product in sufficient quantities for HutchMed’s development or commercialization 
activities for Licensed Products in the Field in the Territory.
HutchMed has agreed to use commercially reasonable efforts to carry out development activities in the Territory as 
agreed by the parties and to seek to obtain and maintain regulatory approval of the Licensed Products in the 
Territory. HutchMed agreed to use commercially reasonable efforts to commercialize Licensed Products in the Field 
in the Territory. HutchMed is responsible for all costs it incurs in developing, obtaining regulatory approval of, and 
commercializing Licensed Products in the Field in the Territory, including costs incurred by HutchMed in 
conducting clinical trials that only include clinical sites in the Territory. For global studies conducted by the 
Company that HutchMed elects to participate in by conducting any such study in the Territory, HutchMed will be 
responsible for enrolling and treating in the Territory 20% of the total number of study patients of such global study 
and will be responsible for costs for those patients enrolled and treated in such trials. HutchMed will also be 
responsible for 20% of the costs of such global studies that are not specific to any territory and the Company will be 
responsible for all other costs of such global studies. HutchMed has agreed to participate in the Company’s EZH-
301 and SYMPHONY-1 (EZH-302) global studies, however under certain circumstances where the SYMPHONY-1 
(EZH-302) global study is not considered a confirmatory trial for regulatory approval in China, the Company shall 
be responsible for the costs of the trial in the Territory.
Pursuant to the HutchMed License Agreement, the Company received a nonrefundable upfront payment of $25.0 
million in September 2021. The Company is also entitled to milestone payments of up to $110.0 million in the 
aggregate for achievement of specified development and regulatory milestones with respect to Licensed Products in 
the Territory, and up to $175.0 million in the aggregate for achievement of specified sales milestones in the 
Territory with respect to the Licensed Products. The Company will also be entitled to receive tiered royalties, 
ranging from a mid-teens percentage to a low twenties percentage based on HutchMed’s cumulative annual net 
sales, if any, of Licensed Products in the Territory. 

F-31
Under the HutchMed License Agreement, the Company issued a warrant to HutchMed (the “HutchMed Warrant”) , 
exercisable at any time prior to August 7, 2025 for up to 5,653,000 shares of the Company’s common stock at an 
exercise price of $11.50 per share. 
Unless earlier terminated, the HutchMed License Agreement will expire upon the expiration of the last royalty term 
for the last Licensed Product in the Field in the Territory. HutchMed may terminate the HutchMed License 
Agreement in its entirety for any or no reason upon 12 months’ prior written notice to the Company. Either party 
may, subject to specified cure periods, terminate the HutchMed License Agreement in the event of the other party’s 
uncured material breach, and under specified circumstances relating to the other party’s insolvency or if the other 
party or its affiliates challenges the validity, patentability, or enforceability of patent rights that are owned by or 
licensed to such party or its affiliates and that are subject to the licenses granted in the HutchMed License 
Agreement.
License Revenue
The Company evaluated the terms of the HutchMed License Agreement and first determined that the HutchMed 
Warrant should be accounted for pursuant to ASC 815, Derivatives and Hedging, with the HutchMed Warrant's fair 
value of approximately $13.0 million (Note 14) at execution considered outside of the revenue arrangement.
The Company identified the following performance obligations at the inception of the HutchMed License 
Agreement: (1) exclusive license with rights to develop, manufacture and commercialize tazemetostat in the 
Territory, (2) research and development services related to global trials, and (3) a material right related to the 
Company’s obligation to provide clinical supply of tazemetostat. In addition, the Company may also provide certain 
technology transfer services related to providing HutchMed with the capability to manufacture tazemetostat, for 
which the Company will receive reimbursement that approximates stand-alone selling price.
The Company evaluated the HutchMed License Agreement under ASC 606, Revenue from Contracts with 
Customers. Based on that evaluation, the $12.0 million of the up-front fee remaining after allocation to the 
HutchMed Warrant and the reimbursement to be received for its research and development services constituted the 
amount of the consideration to be included in the transaction price. In addition, should the global SYMPHONY-1 
(EZH-302) trial not be deemed a confirmatory trial for purposes of regulatory approval in China, the Company shall 
be responsible for reimbursing HutchMed for the costs of the portion of the global SYMPHONY-1 (EZH-302) trial 
that will be performed in China. The Company concluded that this repayment provision represented variable 
consideration under the arrangement. Due to the uncertainty of potential repayment, which is based solely on the 
decision of a regulatory authority, the Company could not assert that it was probable that a significant reversal of 
revenue would not occur. As a result, the Company determined that the transaction price should be fully constrained. 
The Company will evaluate the application of the constraint on a quarterly basis and should the contingency be 
resolved without future payment to HutchMed for the global SYMPHONY-1 (EZH-302) trial, the full upfront fee 
and any reimbursement of research and development services will be included in the transaction price. In addition, 
should the estimated payment to HutchMed for the global SYMPHONY-1 (EZH-302) trial be determined to be less 
than the cumulative up-front fee and research and development reimbursement payments, such excess will be 
included in the transaction price.
None of the development or regulatory milestones have been included in the transaction price, as all such milestone 
amounts were fully constrained. As part of the Company's evaluation of the constraint, the Company considered 
numerous factors, including that receipt of the milestones is outside the control of the Company and contingent upon 
success in future clinical trials and the licensee’s efforts. Any consideration related to sales-based milestones 
(including royalties) will be recognized when the related sales occur as these amounts have been determined to 
relate predominantly to the license granted to HutchMed and therefore are recognized at the later of when the 
performance obligation is satisfied or the related sales occur.
The Company delivered the license during the third quarter of 2021 and expects that based on the estimated 
standalone selling price of the license, that the majority of the consideration in the arrangement will be allocated to 
the license performance obligation, once such consideration is no longer constrained. As the Company performs 
research and development services, it will recognize revenue as such services are performed, upon the transaction 
price no longer being fully constrained.

F-32
GSK 
In January 2011, the Company entered into a collaboration and license agreement with Glaxo Group Limited (an 
affiliate of GlaxoSmithKline plc), or GSK, to discover, develop and commercialize novel small molecule HMT 
inhibitors directed to available targets from the Company’s platform. Under the terms of the agreement, the 
Company granted GSK exclusive worldwide license rights to HMT inhibitors directed to three targets. In March 
2014, the Company and GSK amended certain terms of this agreement for the third licensed target, revising the 
license terms with respect to candidate compounds and amending the corresponding financial terms, including 
reallocating milestone payments and increasing royalty rates as to the third target. Subsequent to a GSK strategic 
portfolio prioritization, the Company received notice in October 2017 that GSK terminated the agreement with 
respect to the third target, effective December 31, 2017, which returned all rights to that target to the Company. On 
December 16, 2021, the Company received written notice from GSK that GSK elected to terminate the 
Collaboration and License Agreement without cause, and in accordance with the terms of the agreement and the 
notice of termination, the termination will be effective on March 16, 2022 . As a result of the termination of the 
agreement, as of the termination effective date, the license rights granted by the Company to GSK will terminate, 
GSK will cease to accrue any financial obligations to the Company and the Company will be entitled to pursue the 
PRMT5 and PRMT1 targets in all fields worldwide without further obligation to GSK. The Company substantially 
completed all of its obligations under this agreement by the end of 2015. The termination of the agreement had no 
impact on the Company’s financial statements.
Eisai 
In April 2011, the Company entered into a collaboration and license agreement with Eisai, under which the 
Company granted Eisai an exclusive worldwide license to its small molecule HMT inhibitors directed to the EZH2 
HMT, including the Company’s product candidate tazemetostat, while retaining an opt-in right to co-develop, co-
commercialize and share profits with Eisai as to licensed products in the United States. 
As of December 31, 2014, the Company had completed its performance obligations under the original agreement. 
In March 2015, the Company entered into an amended and restated collaboration and license agreement with Eisai 
(the “Eisai License Agreement”), under which the Company reacquired worldwide rights, excluding Japan, to its 
EZH2 program, including tazemetostat. Under the Eisai License Agreement, the Company is responsible for global 
development, manufacturing and commercialization outside of Japan of tazemetostat and any other EZH2 product 
candidates, with Eisai retaining development and commercialization rights in Japan, as well as a right to elect to 
manufacture tazemetostat and any other EZH2 product candidates in Japan, and a right of first negotiation for the 
rest of Asia. Eisai waived its right of first negotiation for the rest of Asia in 2018. 
Under the original collaboration and license agreement, Eisai was solely responsible for funding all research, 
development and commercialization costs for EZH2 compounds. Under the Eisai License Agreement, the Company 
is solely responsible for funding global development, manufacturing and commercialization costs for EZH2 
compounds outside of Japan, including the remaining development costs due under a companion diagnostics 
agreement with Roche Molecular Systems, Inc., or Roche Molecular, which was amended to assign all of Roche 
Molecular’s rights and obligations under the companion diagnostics agreement to Roche Sequencing, effective 
January 1, 2020. Eisai is solely responsible for funding Japan-specific development and commercialization costs for 
EZH2 compounds. 
The Company recorded the reacquisition of worldwide rights, excluding Japan, to the EZH2 program, including 
tazemetostat, under the Eisai License Agreement, as an acquisition of an in-process research and development asset. 
As this asset was acquired without corresponding processes or activities that would constitute a business, had not 
achieved regulatory approval for marketing and, absent obtaining such approval, had no alternative future use, the 
Company recorded the $40.0 million upfront payment made to Eisai in March 2015 as research and development 
expense in the consolidated statements of operations and comprehensive loss. The Company also agreed to pay Eisai 
up to $70.0 million in clinical development and regulatory milestones, all of which have been paid, and royalties at a 
percentage in the mid-teens on worldwide net sales of any EZH2 product, excluding net sales in Japan. The 
Company is eligible to receive from Eisai royalties at a percentage in the mid-teens on net sales of any EZH2 
product in Japan.

F-33
During the years ended December 31, 2020 and 2019, Eisai purchased drug product from the Company at cost to 
facilitate development within Japan under the Eisai License Agreement and the Company recognized approximately 
$5.3 million and $3.8 million, respectively, as a reduction to research and development expense. 
During the years ended December 31, 2021 and 2020, the Company recorded $4.6 million and $1.7 million, 
respectively related to worldwide royalties due under the Eisai License Agreement in cost of product revenue based 
on U.S. sales of TAZVERIK and as of December 31, 2021 and 2020, $1.7 million and $0.7 million, respectively in 
royalties were payable under the Eisai License Agreement. 
As of December 31, 2021, and 2020, the Company had accounts receivable of less than $0.1 million, respectively, 
due from Eisai. For additional information regarding certain of the Eisai royalties, see Note 12, Sale of Future 
Royalties. 
In March 2021, the Company and Eisai entered into a supply agreement providing for the manufacture and supply to 
Eisai of tazemetostat drug product. Under the terms of the supply agreement, the Company also agreed to waive its 
right of exclusive supply of tazemetostat drug substance from the Company’s drug substance manufacturer. During 
the year ended December 31, 2021, the Company recognized $6.3 million related to the Company’s waiver of its 
exclusive right to supply of tazemetostat drug substance from the Company’s drug substance manufacturer and 
delivery of tazemetostat drug product in collaboration and other revenue. 
Roche 
In December 2012, Eisai and the Company entered into a companion diagnostics agreement with Roche Molecular, 
under which Eisai and the Company engaged Roche Molecular to develop a companion diagnostic to identify 
patients who possess certain activating mutations of EZH2. In October 2013, this agreement was amended to include 
additional mutations in EZH2. The development costs due under the amended agreement with Roche Molecular 
were the responsibility of Eisai until the execution of the amended and restated collaboration and license agreement 
with Eisai in March 2015, at which time the Company assumed responsibility for the remaining development costs 
due under the agreement. In December 2015, the Company and Eisai entered into a second amendment to the 
companion diagnostics agreement with Roche Molecular. The agreement was further amended in March 2018. 
Under the amended agreement, the Company was responsible for remaining development costs of $10.4 million due 
under the agreement as of March 2018 and Eisai agreed to reimburse the Company $0.9 million of this amount 
related to a regulatory milestone for Japan. In July 2019, the Company entered into a fourth amendment to the 
companion diagnostics agreement. Under the amended agreement, the Company and Roche Molecular agreed to 
divide a $1.0 million regulatory milestone for the United States into two separate milestone payments, of which $0.5 
million was paid by the Company as part of the signed amendment, and the remaining $0.5 million was paid by the 
Company in December 2019 upon the satisfaction of certain conditions set forth in the fourth amendment to the 
companion diagnostics agreement. As part of this fourth amendment, Roche Molecular also assigned all of its rights 
and obligations under the companion diagnostics agreement to Roche Sequencing due to a reorganization at Roche 
group, and this assignment became effective as of January 1, 2020. As of December 31, 2021, the Company is 
responsible for the remaining development costs of $1.0 million due under the agreement. The $0.9 million that 
Eisai agreed to reimburse the Company related to a regulatory milestone for Japan was achieved as of June 30, 2020 
and payment received in the fourth quarter of 2020. In addition, the Company paid $1.0 million for the achievement 
of a development milestone in the fourth quarter of 2020. 
Under the agreement with Roche Sequencing, Roche Sequencing is obligated to use commercially reasonable efforts 
to develop and to make commercially available the companion diagnostic. Roche Sequencing has exclusive rights to 
commercialize the companion diagnostic. On June 18, 2020 the FDA approved the companion diagnostic that is 
intended to identify follicular lymphoma patients with an EZH2 mutation for treatment with tazemetostat.
The agreement with Roche Sequencing will expire when the Company and Eisai are no longer developing or 
commercializing tazemetostat. The Company and Eisai may terminate the agreement by giving Roche Sequencing 
90 days’ written notice if the Company and Eisai discontinue development and commercialization of tazemetostat or 
determine, in conjunction with Roche Sequencing, that the companion diagnostic is not needed for use with 
tazemetostat. Any party may also terminate the agreement in the event of a material breach by any party, in the 
event of material changes in circumstances that are contrary to key assumptions specified in the agreement or in the 

F-34
event of specified bankruptcy or similar circumstances. Under specified termination circumstances, Roche 
Sequencing may become entitled to specified termination fees. 
Boehringer Ingelheim
In November 2018, the Company entered into a collaboration and license agreement with Boehringer Ingelheim 
International GmbH (“Boehringer Ingelheim”) to discover, research, develop and commercialize small molecule 
compounds that are inhibitors of an undisclosed histone acetyltransferase, or HAT, target and an undisclosed 
helicase target, along with associated predictive biomarkers (the “Target Projects”). Under the terms of the 
agreement, the Company granted to Boehringer Ingelheim an exclusive, worldwide license to the undisclosed target 
inhibitors technology. The agreement also included reciprocal licenses to utilize each other’s know-how, patents and 
technologies for activities under the agreement. Further, each party was granted the license to develop, manufacture, 
commercialize and otherwise exploit any compound or product that successfully achieves start of lead optimization 
(“SoLO”). The Company was also obligated to provide R&D services through SoLO approval for both Target 
Projects, and to serve on the Joint Steering Committee (“JSC”) throughout the term of the contract. The parties were 
to jointly research and develop the shared helicase target program and will share commercialization activities within 
the United States. Boehringer Ingelheim had agreed to assume responsibility for commercialization outside of the 
United States. On December 21, 2020, the Company received written notice from Boehringer Ingelheim that it 
elected to terminate the Collaboration Agreement without cause, and in accordance with the terms of the 
Collaboration Agreement. The termination became effective on January 31, 2021. The Target Project for the 
helicase target and the reciprocal licenses terminated as of this date. The Company is entitled to pursue the HAT 
target and helicase target programs in all fields worldwide without further obligation to Boehringer Ingelheim.
Agreement Structure
Under the terms of the agreement, the Company received a $15.0 million upfront payment and $5.0 million in 
research funding for the costs to be incurred by the Company in connection with its research activities, payable 
quarterly in four equal installments during 2019. At its discretion, Boehringer Ingelheim had the option to extend the 
research period by up to one year, subject to the Company’s agreement to the specified research activities and 
additional research funding. During the third quarter of 2019, Boehringer Ingelheim’s option to extend the research 
period expired unexercised, and therefore the research period ended on December 31, 2019. In March 2020, the 
Company and Boehringer Ingelheim amended the agreement to extend the research period for the shared program 
targeting enzymes within helicase families with Boehringer Ingelheim providing research funding of $0.4 million. 
Additionally, in March 2020, the Company received notice of termination for the program targeting enzymes with 
HAT families, which program termination became effective in June 2020. In September 2020, the Company and 
Boehringer Ingelheim further amended the agreement to extend the research period for the shared program targeting 
enzymes within helicase families with Boehringer Ingelheim to provide research funding of $0.1 million. The 
additional research activities were completed prior to the end of 2020.
Collaboration Revenue 
Through December 31, 2021, the Company has recognized $26.0 million in total collaboration revenue since the 
inception of this collaboration. During the years ended December 31, 2021, 2020 and 2019, the Company 
recognized revenue of $0, $0.5 million and $23.8 million, respectively. The Company will not receive any additional 
revenue under the terms of its agreement with Boehringer Ingelheim.

F-35
12. Sale of Future Royalties
On November 4, 2019, the Company entered into a loan agreement with BioPharma Credit PLC, or the Collateral 
Agent, and the Lenders, providing for up to $70.0 million in secured term loans to be advanced in up to three 
tranches, or the Loan Agreement. As of December 31, 2020, the Company had borrowed an aggregate principal 
amount under the first tranche of $25.0 million (the “Tranche A Note Payable”), the second tranche of $25.0 million 
(the “Tranche B Note Payable”), and the third tranche of $20.0 million (the “Tranche C Note Payable”) under the 
Loan Agreement. On November 3, 2020, the Company, the Collateral Agent and the Lenders amended and restated 
the Loan Agreement, (as amended and restated, the “Amended and Restated Loan Agreement”), to provide for, 
among other things, an additional secured term loan of $150.0 million, or the Tranche D Loan. On November 18, 
2020, the Company borrowed the Tranche D Loan (See Note 13, Long-Term Debt). 
On November 4, 2019, the Company also executed a purchase agreement (the “RPI Purchase Agreement”) with 
RPI. Pursuant to the RPI Purchase Agreement, the Company agreed to sell to RPI 6,666,667 shares of its common 
stock, a warrant to purchase up to 2,500,000 shares of common stock at an exercise price of $20.00 per share (the 
“Common Stock Warrant”), and all of the Company’s rights to receive royalties from Eisai with respect to net sales 
by Eisai of tazemetostat products in Japan pursuant to the Eisai License Agreement and any successor arrangement 
for Japan sales (the “Japan Royalty”, and collectively, the “Transaction”). In consideration for the sale of shares of 
common stock, the Common Stock Warrant and the Japan Royalty, RPI paid the Company $100.0 million upon the 
closing of the RPI Purchase Agreement. In addition, RPI agreed, in connection with RPI’s acquisition from Eisai of 
the right to receive royalties from the Company under the Eisai License Agreement, to reduce the Company’s 
royalty obligation by low single digits upon the achievement of specified annual net sales levels over $1.5 billion. In 
addition, under the RPI Purchase Agreement, the Company had the right to sell, and RPI had the obligation to 
purchase, subject to certain conditions, including a maximum purchase price of $20.00 per share, $50.0 million of 
shares of common stock at the Company’s option for an 18-month period from the date of execution of the RPI 
Purchase Agreement (the “Put Option”). In February 2020, the Company sold 2.5 million shares of its common 
stock to RPI, for an aggregate of $50.0 million in proceeds pursuant to the Put Option. Additionally, under the terms 
of the RPI Purchase Agreement, the founder and chief executive officer of RP Management, an affiliate of RPI, and 
a co-founder of Pharmakon Advisors LP, an affiliate of the Lenders was elected as a director of the Company. As of 
December 31, 2021 and 2020, RPI and its affiliates owned approximately 8.6% and 9.0% of the Company’s 
common stock, respectively.
The Company accounted for the Loan Agreement and RPI Purchase Agreement as a single arrangement as RPI and 
the Lenders are related parties and the agreements were negotiated together. The aggregate proceeds of $125.0 
million were allocated on a relative fair value basis, which approximated their respective actual fair values, to the 
four units of accounting pursuant to the transaction as follows: (1) $79.0 million to the common stock issued to RPI 
based on the closing price of the Company’s common stock on the date of the transaction, (2) $8.4 million to the 
Common Stock Warrant to purchase shares of common stock, based on the Black-Scholes option pricing model, (3) 
$12.6 million to the liability related to the sale of future royalties based on a discounted cash flow model and (4) 
$25.0 million to the Tranche A Note Payable based on the terms of the Loan Agreement. Transaction costs of $2.0 
million were allocated directly to the units of accounting it relates to. 
Although the Company sold all of its rights to receive the Japan Royalty, under the terms of the RPI Agreement, the 
Company continues to own all tazemetostat intellectual property rights and at execution had significant continuing 
involvement in the generation of these royalties. Due to the Company’s continuing involvement, the Company will 
continue to account for any royalties due as revenue and recorded the proceeds from this transaction as a liability 
(“Royalty Obligation”) that will be accreted using the effective interest method over the estimated life of the RPI 
Purchase Agreement. 
As royalties are remitted to RPI from Eisai, the balance of the Royalty Obligation will be effectively repaid over the 
life of the Eisai License Agreement. In order to determine the accretion of the Royalty Obligation, the Company is 
required to estimate the total amount of future royalty payments to RPI over the life of the Eisai License Agreement. 
The $12.6 million recorded at execution will be accreted to the total of these royalty payments as interest expense 

F-36
over the life of the Royalty Obligation. At execution, the Company’s estimate of this total interest expense resulted 
in an effective annual interest rate of approximately 9.01%. This estimate contains significant assumptions that 
impact both the amount recorded at execution and the interest expense that will be recognized over the royalty 
period. The Company periodically assesses the estimated royalty payments to RPI from Eisai and to the extent the 
amount or timing of such payments is materially different than the original estimates, an adjustment is made to the 
effective interest rate, which will be recorded prospectively to increase or decrease interest expense. There are a 
number of factors that could materially affect the amount and timing of royalty payments to RPI from Eisai, and 
correspondingly, the amount of interest expense recorded by the Company, most of which are not within the 
Company’s control. Such factors include, but are not limited to, delays or discontinuation of development of 
tazemetostat in Japan, regulatory approval, changing standards of care, the introduction of competing products, 
manufacturing or other delays, generic competition, intellectual property matters, adverse events that result in 
governmental health authority imposed restrictions on the use of the drug products, significant changes in foreign 
exchange rates as the royalties remitted to RPI are made in U.S. dollars (USD) while the underlying Japan sales of 
tazemetostat will be made in currencies other than USD, and other events or circumstances that are not currently 
foreseen as tazemetostat is still under development in Japan and subject to regulatory approval. Changes to any of 
these factors could result in increases or decreases to both royalty revenues and interest expense. On June 23, 2021, 
Eisai announced that it had obtained manufacturing and marketing approval for the EZH2 inhibitor “Tazverik® 
Tablets 200 mg” (tazemetostat hydrobromide) in Japan with the indication of relapsed or refractory EZH2 gene 
mutation-positive follicular lymphoma (only when standard treatment is not applicable), which caused the Company 
to reassess the estimated future royalty payments to RPI. As of December 31, 2021, the Company’s assessment of 
the estimated future royalty payments to RPI resulted in a current effective interest rate of approximately 9.19%. 
The following table shows the activity of the Royalty Obligation since the transaction inception through 
December 31, 2021:
Year Ended
December 31,
2021
(In thousands )
Proceeds from sale of future royalties
$
12,601
Non-cash royalty revenue
(31)
Non-cash interest expense recognized
3,357
Liability related to the sale of future royalties - ending balance
15,927
Less current portion
(273)
Related party liability related to sale of future royalties, net of current 
portion
$
15,654
During the year ended December 31, 2021, the Company recorded non-cash royalties from net sales of tazemetostat 
in Japan of less than $0.1 million. During the years ended December 31, 2020 and 2019, the Company did not 
record non-cash royalties from net sales of tazemetostat in Japan. During the years ended December 31, 2021, 2020 
and 2019 the Company recorded $1.8 million, $1.4 million and $0.2 million, respectively, of related non-cash 
interest expense.

F-37
13. Long-Term Debt
On November 4, 2019, the Company entered into the Loan Agreement, which provided for up to $70.0 million in 
secured term loans to be advanced in up to three tranches. The Company borrowed $70.0 million in the aggregate 
under the three tranches pursuant to the Loan Agreement. With the FDA’s June 2020 approval of tazemetostat for 
the treatment of FL in the United States, the Company also had the right, but not the obligation, to request up to an 
additional $300.0 million in secured term loans, subject to the approval of the Lenders, provided the Company has 
not prepaid any outstanding term loans at the time of such request and such request is made before November 18, 
2021. On November 3, 2020, the Company entered into the Amended and Restated Loan Agreement with the 
Lenders. The Amended and Restated Loan Agreement provides for, among other things, an additional secured term 
loan of $150.0 million, or the Tranche D Loan. On November 3, 2020, the Company also delivered written notice to 
the Lenders to draw down the Tranche D Loan, which was funded on November 18, 2020. The Company paid a 
commitment fee of 2.00% of the original $70.0 million committed facility amount in November 2019 and 2% of the 
$150.0 million Tranche D Loan in November 2020, as well as expenses incurred by the Lender in executing the 
agreements. 
The interest rate for the Tranche D Loan will be determined by reference to a Eurodollar rate plus 7.75% above such 
Eurodollar rate. The Eurodollar rate will have a 2.00% floor. The Tranche D Loan will be due in eight equal 
quarterly principal payments commencing on the 51st month anniversary of the date on which the Lenders fund the 
Tranche D Loan. All unpaid principal and interest under the Tranche D Loan will be due and payable on the 72nd 
month anniversary of the date on which the Lenders funded the Tranche D Loan. 
The Amended and Restated Loan Agreement also amended the payment period principal and interest for the first 
three tranches of term loans. Under the original terms, the Company was required to make interest only payments on 
the outstanding obligation through February 28, 2023, and thereafter eight quarterly payments of principal and 
interest. Under the amended and restated terms, the Company is required to make interest only payments on the 
$70.0 million outstanding obligation through November 2023, and thereafter four quarterly payments of principal 
and interest. All unpaid principal and interest on the $70.0 million borrowed under the original Loan Agreement is 
due and payable in November 2024, the 60th month anniversary of the date on which the Lenders funded the first 
tranche of term loans. The interest rates for the existing tranches of term loans remain unchanged and will continue 
to be determined by reference to a Eurodollar rate plus 7.75% above such Eurodollar rate. The Eurodollar rate will 
have a 2.00% floor.
Each of the four term loans may be prepaid before maturity in whole or in part, however there is a $50.0 million 
minimum prepayment for any prepayment of the loans. If the Company prepays any tranche of term loans, in whole 
or in part, during the first 36 months from the date on which the Lenders funded such tranche of term loans, then the 
Company must pay a prepayment premium equal to the greater of (x) a make-whole amount equal to the interest that 
would have accrued on the principal amount to be prepaid and (y) a premium equal to 0.03 multiplied by the 
principal amount to be prepaid. If the Company prepays a tranche of term loan, in whole or in part, between the 36th 
month and 48th month from the date on which the Lenders funded such tranche of term loans, then the Company 
must pay a prepayment premium equal to 0.02 multiplied by the principal amount to be prepaid. If the Company 
prepays a tranche of term loans, in whole or in part, between the 48th month and 60th month from the date on which 
the Lenders funded such tranche of term loans, then the Company must pay a prepayment premium equal to 0.01 
multiplied by the principal amount to be prepaid.
The Amended and Restated Loan Agreement was accounted for as a debt modification based on a comparison of the 
present value of the cash flows under the terms of the debt immediately before and after the effective date of The 
Amended and Restated Loan Agreement, which resulted in a change of less than 10%. As a result, issuance costs 
paid to the Lenders in connection with The Amended and Restated Loan Agreement were recorded as a reduction of 
the carrying amount of the debt liability and unamortized issuance costs as of the date of the modification are 
amortized to interest expense over the repayment term of The Amended and Restated Loan Agreement.
The obligations under the Amended and Restated Loan Agreement, including the Company’s payment obligations in 
respect of the Tranche D Loan are secured by the first priority security interest in and a lien on substantially all of 
the assets of the Company, subject to certain exceptions, that the Company granted to the Lenders in connection 
with the first tranche of term loans under the Loan Agreement.

F-38
The Amended and Restated Loan Agreement contains certain customary representations and warranties, affirmative 
and negative covenants and events of default applicable to the Company and its subsidiaries. If an event of default 
occurs and is continuing, the Collateral Agent may, among other things, accelerate the loans and foreclose on the 
collateral. The Company has determined that the risk of subjective acceleration under the material adverse events 
clause is not probable and therefore has classified the outstanding principal in non-current liabilities based on 
scheduled principal payments.
The Company has the following minimum aggregate future loan payments at December 31, 2021 (in thousands): 
Year Ended
December 31,
2021
2022
—
2023
—
2024
70,000
2025
75,000
2026
75,000
Total minimum payments
220,000
Less amounts representing interest and discount
(3,539)
Less current portion
—
Related party long-term debt, net of debt discount
$
216,461
For the years ended December 31, 2021, 2020 and 2019, interest expense related to the Company's Amended and 
Restated Loan Agreement was approximately $22.5 million, $7.2 million and $0.3 million, respectively. The total 
carrying value of debt is classified as long-term on the Company's consolidated balance sheet as of December 31, 
2021 and 2020, respectively.
14. Stockholders’ Equity (Deficit)
Common Stock
On March 24, 2020, the Company’s board of directors adopted, subject to stockholder approval, an amendment to 
the Company’s Restated Certificate of Incorporation to increase the number of authorized shares of common stock, 
$0.0001 par value per share, from 125,000,000 to 150,000,000 (the “Charter Amendment”). At the Company’s 2020 
Annual Meeting of Stockholders, the stockholders of the Company approved the Charter Amendment, which was 
filed with the Secretary of State of the State of Delaware on May 29, 2020. On April 8, 2021, the Company’s board 
of directors adopted, subject to stockholder approval, an amendment to the Company’s Restated Certificate of 
Incorporation to increase the number of authorized shares of common stock from 150,000,000 to 225,000,000 (the 
"2021 Charter Amendment"). At the Company’s 2021 Annual Meeting of Stockholders, the stockholders of the 
Company approved the 2021 Charter Amendment, which was filed with the Secretary of State of the State of 
Delaware on June 11, 2021. The number of authorized shares of preferred stock was not affected by these Charter 
Amendments.
Each share of common stock entitles the holder to one vote on all matters submitted to a vote of the Company’s 
stockholders. Common stockholders are entitled to dividends when and if declared by the board of directors. 
2021 At-the-Market Offering Program
On May 6, 2021, the Company entered into an Open Market Sale AgreementSM (“ATM Sale Agreement”), with 
Jefferies LLC (“Jefferies”) to sell, from time to time, shares of the Company's common stock having an aggregate 
offering price of up to $200.0 million through an “at the market offering” as defined in Rule 415 under the Securities 
Act of 1933, as amended, under which Jefferies would act as sales agent (the "ATM Offering"). The shares that may 
be sold under the ATM Sale Agreement, if any, are issued and sold pursuant to the Company’s shelf registration 
statement on Form S-3 that was declared effective by the Securities and Exchange Commission on May 13, 2021. 
The Company agreed to compensate Jefferies at a fixed commission rate equal to 3.0% of the gross sales proceeds 
of such shares.

F-39
From the initiation of the ATM Offering through December 31, 2021, the Company has issued and sold 3,840,977 
shares under the ATM Offering, resulting in aggregate net proceeds of $16.0 million after deducting issuance costs 
of $0.5 million.
RPI Put Option
In February 2020, the Company sold 2,500,000 shares of its common stock in connection with the exercise of its Put 
Option to sell shares of its common stock for an aggregate of $49.9 million in net proceeds after deducting financing 
costs of $0.1 million. (see Note 12, Sale of Future Royalties). 
Convertible Preferred Stock
The Company has 337,800 shares of Series A Convertible Preferred Stock outstanding as of December 31, 2021 and  
2020.
Voting Rights
Shares of Series A Preferred Stock will generally have no voting rights except as required by law and except that the 
consent of the holders of a majority of the outstanding shares of Series A Preferred Stock will be required to amend 
the terms of the Series A Preferred Stock or take certain other actions with respect to the Series A Preferred Stock.
Dividends
Shares of Series A Preferred Stock will be entitled to receive dividends equal to (on an as-if-converted-to-common 
stock basis), and in the same form and manner as, dividends actually paid on shares of the Company’s common 
stock.
Liquidation Rights
Subject to the prior and superior rights of the holders of any senior securities of the Company, upon liquidation, 
dissolution or winding up of the Company, whether voluntary or involuntary, each holder of shares of Series A 
Preferred Stock shall be entitled to receive, in preference to any distributions of any of the assets or surplus funds of 
the Company to the holders of common stock, an amount equal to $0.001 per share of Series A Preferred Stock, plus 
an additional amount equal to any dividends declared but unpaid on such shares, before any payments shall be made 
or any assets distributed to holders of any class of common stock.
If, upon any such liquidation, dissolution or winding up of the Company, the assets of the Company shall be 
insufficient to pay the holders of shares of the Series A Preferred Stock the amount required under the preceding 
sentence, then all remaining assets of the Company shall be distributed ratably to holders of the shares of the Series 
A Preferred Stock in proportion to the respective amounts which would otherwise be payable in respect of the shares 
held by them upon such distribution if all amounts payable on or with respect to such shares were paid in full.
Conversion
Each share of Series A Preferred Stock shall be convertible, at any time and from time to time from and after the 
issuance date, at the option of the holder thereof, into a number of shares of common stock equal to 10 shares of 
common stock, provided that the holder will be prohibited from converting Series A Preferred Stock into shares of 
the Company’s common stock if, as a result of such conversion, the holder, together with its affiliates and attribution 
parties, would own more than 9.99% of the total number of shares of common stock then issued and outstanding. 
The holder can change this requirement to a higher or lower percentage, not to exceed 9.99% of the number of 
shares of common stock outstanding, upon 61 days’ notice to the Company.
In February 2020, 12,200 shares of Series A Preferred Stock were converted to 122,000 shares of common stock. 

F-40
Redemption
The Company is not obligated to redeem or repurchase any shares of Series A Preferred Stock. Shares of Series A 
Preferred Stock are not entitled to any redemption rights or mandatory sinking fund or analogous fund provisions.
Warrants
In November 2019, the Company issued the Common Stock Warrant for the purchase of up to 2,500,000 shares of 
Common Stock at an exercise price of $20.00 per share to RPI pursuant to the RPI Purchase Agreement (for 
additional information see Note 12, Sale of Future Royalties), which was classified as equity and recorded at its 
relative fair value of $8.4 million to additional paid-in-capital on the Company's consolidated balance sheets. The 
Common Stock Warrant remains outstanding as of December 31, 2021.
In August 2021, the Company issued the HutchMed Warrant to HutchMed under the HutchMed License Agreement, 
exercisable at any time prior to August 7, 2025 for up to 5,653,000 shares of the Company’s common stock at an 
exercise price of $11.50 per share. Under the HutchMed Warrant, the number of shares issuable under the warrant is 
reduced from 5,653,000 to 2,826,500 in the event that the HutchMed License Agreement is terminated for certain 
reasons as more fully described in the HutchMed License Agreement. Due to this provision, the Company 
concluded that the warrant does not meet the exception from derivative accounting pursuant to ASC 815, 
Derivatives and Hedging, which requires that the warrant be accounted for as a derivative. Accordingly, the 
Company recorded a warrant liability in the amount of approximately $13.0 million upon issuance. The fair value of 
the HutchMed Warrant was determined using a Black-Scholes and Monte Carlo pricing model.
The HutchMed Warrant is subject to revaluation at each balance sheet date and any changes in fair value are 
recorded as a non-cash gain or (loss) in the Company's consolidated statement of operations and comprehensive loss 
as a component of other income (expense), net until the earlier of the exercise or expiration of the HutchMed 
Warrant or upon the completion of a liquidation event. 
The Company recorded non-cash gains of approximately $11.1 million during 2021 in its consolidated statement of 
operations and comprehensive loss attributable to the decreases in the fair value of the warrant liability that resulted 
from a reduction in the Company's stock price as of December 31, 2021.
The following table rolls forward the fair value of the HutchMed Warrant liability, the fair value of which is 
determined by Level 3 inputs at inception on August 7, 2021, and as of December 31, 2021:
(In thousands)
Fair value at inception
$
13,050
Decrease in fair value
(11,120)
Fair value at December 31, 2021
$
1,930
The key assumptions used to value the HutchMed Warrant were as follows:
Inception
As of December 31, 2021
Risk-free interest rate
0.6%
1.05%
Expected term (in years)
4.0 years
3.6 years
Expected volatility of underlying stock
70.0%
70.0%
Expected dividend yield
-
-
Stock price
$
6.47
$
2.50
15. Employee Benefit Plans 
Stock Incentive Plans 
The Company maintains one stock incentive plan, the 2013 Stock Incentive Plan, as well as the 2013 Employee 
Stock Purchase Plan.

F-41
In addition, during the year ended December 31, 2021, the Company granted options to purchase an aggregate of 
248,366 shares of Epizyme common stock and 106,955 restricted stock units (RSUs) to four new employees as 
equity inducement awards outside of the Company's 2013 Stock Incentive Plan and material to the employees’ 
acceptance of employment with the Company. These equity awards were approved in accordance with Nasdaq 
Listing Rule 5635(c)(4), and these equity awards remained outstanding as of December 31, 2021. The options have 
a weighted average exercise price of $5.12 per share, and the RSUs have a weighted average grant date fair value of 
$5.08 per unit. These inducement awards are included in stock-based compensation expense and the following 
tables.
Stock-Based Compensation Expense
Stock-based compensation expense is classified in the consolidated statements of operations and comprehensive loss 
as follows: 
 
Year Ended December 31,
2021
2020
2019
(In thousands)
Research and development
$
8,360 $
9,093
$
6,295
General and administrative
18,427
18,516
11,721
Total
$
26,787 $
27,609
$
18,016
Stock Options 
The weighted-average grant date fair value of options, estimated as of the grant date using the Black-Scholes option-
pricing model. Weighted average assumptions used in this pricing model on the date of grant for options granted to 
employees are as follows: 
 
Year Ended December 31,
2021
2020
2019
Risk-free interest rate
0.7%
0.9%
2.2%
Expected life of options
5.89 years
5.99 years
6.0 years
Expected volatility of underlying stock
70.0%
70.9%
72.0%
Expected dividend yield
0.0%
0.0%
0.0%
The following is a summary of stock option activity for the year ended December 31, 2021: 
Number of
Options
Weighted
Average
Exercise
Price per
Share
Weighted
Average
Remaining
Contractual
Term
Aggregate
Intrinsic
Value
(In thousands)
(In years)
(In thousands)
Outstanding at December 31, 2020
10,225
$
14.77
Granted
6,422
7.81
Exercised
(104)
8.83
Forfeited or expired
(3,597)
13.88
Outstanding at December 31, 2021
12,946
$
11.61
7.62 $
-
Exercisable at December 31, 2021
5,463
$
14.39
5.82 $
-

F-42
During the years ended December 31, 2021, 2020 and 2019, the Company granted stock options to purchase an 
aggregate of 6,421,792 shares, 3,522,258 shares, and 4,222,693 shares, respectively, at weighted-average grant date 
fair values per option share of $4.79, $11.69, and $6.99, respectively. The total grant date fair value of options that 
vested during the years ended December 31, 2021, 2020 and 2019 was $27.2 million, $17.4 million, and $13.2 
million, respectively. The aggregate intrinsic value of stock options exercised was $0.1 million in 2021, $5.5 million 
in 2020 and $1.2 million in 2019. 
As of December 31, 2021, there was $37.3 million in unrecognized stock-based compensation related to stock 
options that are expected to vest. These costs are expected to be recognized over a weighted average remaining 
vesting period of 2.3 years. 
Restricted Stock Units
During the year-ended December 31, 2021, 2,240,217 restricted stock units (“RSUs”) were granted to executives 
and employees and 105,944 RSUs were granted to non-employee directors. The awards were service-based. 
Assuming all service conditions are achieved, the executive and employee RSUs will vest as to 50%, 33%, and 25%, 
respectively, of the shares of Company common stock underlying the RSUs on an annual basis over two, three, or 
four year period of time from the grant dates, respectively, and the non-employee director RSUs will vest as to 
100% of the shares of Company common stock underlying the RSUs in full on the earlier of the first anniversary of 
the grant date and the date of the succeeding annual meeting of stockholders.
Number of
Units
Weighted
Average Grant
Date Fair Value
per Unit
(In thousands except per share data)
Outstanding at December 31, 2020
668
$
17.56
Granted
2,346
7.74
Vested
(187)
17.20
Forfeited
(605)
12.15
Outstanding at December 31, 2021
2,222
$
8.70
Compensation expense totaling $4.9 million, $2.7 million, and $0.5 million was recognized for the service-based 
RSUs for the years-ended December 31, 2021, 2020 and 2019, respectively. 
As of December 31, 2021, there was $14.3 million of unrecognized compensation cost related to service-based 
RSUs that are expected to vest. These costs are expected to be recognized over a weighted average remaining 
vesting period of 2.2 years. 
During 2019, the Company granted 604,000 RSUs to executives and employees, which contained performance 
conditions, 20% of the RSUs vested on June 30, 2019, 25% of the RSUs vested on January 23, 2020, 20% of the 
RSUs vested on March 24, 2020, and 30% of the RSUs vested on June 25, 2020 in connection with achievement of 
the final performance milestone. 
Compensation expense totaling $3.5 million and $3.6 million was recognized for the performance-based RSUs for 
the years-ended December 31, 2020 and 2019, respectively. 
There was no unrecognized compensation cost as of December 31, 2020, related to performance-based RSUs, as all 
of the performance conditions have been achieved. 
401(k) Savings Plan 
The Company has a defined contribution 401(k) savings plan (the “401(k) Plan”). The 401(k) Plan covers 
substantially all employees, and allows participants to defer a portion of their annual compensation on a pretax basis. 
Company contributions to the 401(k) Plan may be made at the discretion of the board of directors. During the year 

F-43
ended December 31, 2014, the Company implemented a matching contribution to the 401(k) Plan, matching 50% of 
an employee’s contribution up to a maximum of 3% of the participant’s compensation. Company contributions to 
the 401(k) plan totaled $1.4 million, $1.2 million and $0.6 million in the years ended December 31, 2021, 2020 and 
2019, respectively. 
16. Loss per Share 
As described in Note 2, Summary of Significant Accounting Policies, the Company computes basic and diluted 
earnings (loss) per share using a methodology that gives effect to the impact of outstanding participating securities 
(the “two-class method”). The two-class method was not applied for the years ended December 31, 2021, 2020, and 
2019 due to the net loss recognized in each of those periods. In 2019 the net loss applicable to common stockholders 
did not equal net loss due to the accretion of the beneficial conversion feature of Series A Preferred Stock in the 
amount of $2.9 million. The beneficial conversion feature was initially recorded as a discount on the Series A 
Preferred Stock with a corresponding amount recorded to Additional Paid-in Capital. The discount on the Series A 
Preferred Stock was then immediately written off as a deemed dividend as the Series A Preferred Stock does not 
have a stated redemption date and is immediately convertible at the option of the holder.
Basic and diluted loss per share allocable to common stockholders are computed as follows: 
 
Year Ended December 31,
2021
2020
2019
(In thousands except per share data)
Net loss
$ (251,122) $ (231,694) $
(170,295)
Accretion of Series A Preferred Stock
—
—
(2,940)
Net loss attributable to common stockholders
$ (251,122) $ (231,694) $
(173,235)
Weighted average shares outstanding
102,646
100,960
89,891
Basic and diluted loss per share allocable to 
common stockholders
$
(2.45) $
(2.29) $
(1.93)
The following common stock equivalents were excluded from the calculation of diluted loss per share allocable to 
common stockholders because their inclusion would have been anti-dilutive: 
 
Year Ended December 31,
2021
2020
2019
(In thousands)
Stock options
12,946
10,225
8,087
Restricted stock units
2,222
669
757
Shares issuable under employee stock purchase plan
155
98
38
Series A Preferred Stock (if converted)
3,378
3,378
3,500
Warrants
8,153
2,500
2,500
26,854
16,870
14,882
For the year ended December 31, 2019, the above table does not include the up to 6,250,000 shares subject to the 
Company’s option to sell additional shares to RPI pursuant to the Put Option as the decision to exercise this option 
was within the Company’s control. On December 30, 2019, the Company exercised its option to sell 2,500,000 
shares of Common Stock to RPI for an aggregate of $50.0 million. The sale was effected on February 11, 2020. 
17. Subsequent Events
Common Stock Offering
In January 2022, the Company raised approximately $79.5 million in net proceeds (after deducting underwriting 
discounts and commissions and estimated offering costs, but excluding any expenses and other costs reimbursed by 
the underwriters) from the sale of 56,666,667 shares of its common stock in a public offering at a price of $1.50 per 
share.

F-44
Operating Cost Reduction
On March 1, 2022, the Company announced a cross-functional reduction of approximately 12% of its current 
workforce under a cost reduction plan. Affected employees will be offered separation benefits, including severance 
payments along with temporary healthcare coverage assistance. The Company estimates that the severance and 
termination-related costs will be approximately $2.8 - 3.2 million and expects to record these charges in the first 
quarter of 2022. The Company expects that payments of these costs will be made through the end of the fourth 
quarter of 2022.

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TRANSFER AGENT
The transfer agent is responsible, among other things, for handling 
stockholder questions regarding lost stock certificates, address 
changes, including duplicate mailings and changes in ownership 
or name in which shares are held. These requests may be 
directed to the transfer agent at the following addresses or 
telephone numbers:
CAUTIONARY NOTE ON FORWARD-LOOKING STATEMENTS
Any statements in this annual report to stockholders about future expectations, plans and prospects for Epizyme, Inc. and other statements containing the words “anticipate,” “believe,” “estimate,” “expect,” 
“intend,” “may,” “plan,” “predict,” “project,” “target,” “potential,” “will,” “would,” “could,” “should,” “continue,” and similar expressions, constitute forward-looking statements within the meaning of The Private 
Securities Litigation Reform Act of 1995. Actual results may differ materially from those indicated by such forward-looking statements as a result of various important factors, including: whether commercial sales of 
TAZVERIK for epithelioid sarcoma and follicular lymphoma in the approved indications will be successful or will increase to the levels anticipated or at all; whether the prioritization of the company’s development 
activities and cost reductions will achieve the company’s objectives or forecasted cost savings; whether tazemetostat will receive marketing approval for epithelioid sarcoma or follicular lymphoma in other 
jurisdictions, full approval in the United States or approval in any other indication; uncertainties inherent in the initiation of future clinical studies and in the availability and timing of data from ongoing clinical studies; 
whether results from preclinical studies or earlier clinical studies of the company’s product candidates will be predictive of the results of future trials, such as the ongoing confirmatory trials of TAZVERIK; whether results 
from clinical studies will warrant meetings with regulatory authorities, submissions for regulatory approval or review by governmental authorities under the accelerated approval process; whether the company will 
receive regulatory approvals, including accelerated approval, to conduct trials or to market products; whether the company’s collaborations and licensing agreements with third parties will be successful; 
uncertainties as to the impact of the COVID-19 pandemic on the company’s business, results of operations and financial condition; whether the company’s cash resources will be sufficient to fund the company’s 
foreseeable and unforeseeable operating expenses and capital expenditure requirements; other matters that could affect the availability or commercial success of tazemetostat; and other factors discussed in the 
“Risk Factors” section of the company’s most recent Form 10-K or Form 10-Q filed with the SEC and in the company’s other filings from time to time with the SEC. In addition, the forward-looking statements included in 
this annual report to stockholders represent the company’s views as of the date hereof and should not be relied upon as representing the company’s views as of any date subsequent to the date hereof (provided 
that any such statements in the company’s SEC filings represent the company’s views as of the date of such filing). The company anticipates that subsequent events and developments will cause the company’s 
views to change. However, while the company may elect to update these forward-looking statements at some point in the future, the company specifically disclaims any obligation to do so.
TAZVERIK® is a registered trademark of Epizyme, Inc.
Computershare Investor Services 
P.O. Box 505000 
Louisville, KY 40233-5005 
877.373.6374 or 781.575.2879 
www.computershare.com/investor
BOARD OF DIRECTORS
Ken Bate
Biopharmaceutical Consultant
Roy A. Beveridge, M.D. 
Medical Oncologist
Grant Bogle
Epizyme
Kevin T. Conroy 
Exact Sciences
Michael F. Giordano, M.D.
Biopharmaceutical Consultant
Carl Goldfisher, M.D. 
Bay City Capital LLC
Pablo Legorreta 
Royalty Pharma
David M. Mott 
Mott Family Capital
Victoria Richon, Ph.D. 
Ribon Therapeutics
Carol Stuckley, M.B.A.
Financial Consultant
SENIOR LEADERSHIP
Grant Bogle 
President and Chief Executive Officer
Dr. Shefali Agarwal 
Executive Vice President, 
Chief Medical and Development Officer
Joe Beaulieu
Senior Vice President, Finance
Jerald Korn
Chief Operating Officer
Jeffery Kutok, M.D., Ph.D.
Chief Scientific Officer
Rebecca Mehrwerth
Senior Vice President, Head of 
Commercial
Tanja Weber
Chief Business Officer 
John Weidenbruch 
Senior Vice President, General Counsel
CORPORATE COUNSEL
WilmerHale
INDEPENDENT AUDITORS
Ernst & Young LLP 
200 Clarendon Street 
Boston, MA 02116
INVESTOR RELATIONS
Caitlin Stern
Real Chemistry 
cstern@realchemistry.com
2022 ANNUAL MEETING
The 2022 Annual Meeting of 
Stockholders will be held at: 
10:00 a.m. ET on May 17, 2022
EPIZYME, INC.
400 Technology Square, 4th Floor 
Cambridge, MA 02139 
Phone: 617.229.5872 
www.epizyme.com
NASDAQ: EPZM

400 Technology Square, 4th Floor 
Cambridge, MA 02139
Phone: 617.229.5872 
www.epizyme.com
NASDAQ: EPZM