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Merus

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FY2024 Annual Report · Merus
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UNITED STATES 
SECURITIES AND EXCHANGE COMMISSION 
Washington, D.C. 20549 
 
FORM 10-K 
 
(Mark One) c
☒
ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934
For the fiscal year ended December 31, 2024
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 001-37773
 
MERUS N.V.
(Exact name of Registrant as specified in its Charter) 
 
 
The Netherlands
Not Applicable
(State or other jurisdiction of
incorporation or organization)
(I.R.S. Employer
Identification No.)
Uppsalalaan 17
3584 CT Utrecht
The Netherlands
Not Applicable
(Address of principal executive offices)
(Zip Code)
Registrant’s telephone number, including area code:
+31 30 253 8800
 
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 shares, 
nominal value €0.09 per share
MRUS
The Nasdaq Stock Market LLC 
(Nasdaq Global 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 15(d) of the 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 the 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. ☒
If securities are registered pursuant to Section 12(b) of the Act, indicate by check mark whether the financial statements of the registrant included in 
the filing reflect the correction of an error to previously issued financial statements. ☐
Indicate by check mark whether any of those error corrections are restatements that required a recovery analysis of incentive-based compensation 
received by any of the registrant’s executive officers during the relevant recovery period pursuant to §240.10D-1(b). ☐
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 voting and non-voting common equity held by non-affiliates of the registrant, based on the closing price of the 
shares of common shares on The Nasdaq Stock Market on June 30, 2024, was approximately $3,996.5 million. 
The number of shares of registrant’s Common Shares outstanding as of February 21, 2025 was 69,090,469.
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 2025 Annual General Meeting of Shareholders are incorporated by reference into Part III of this 
Annual Report on Form 10-K to the extent stated herein.
Auditor Firm ID
1012
Auditor Name: KPMG Accountants N.V.
Auditor Location: Amstelveen, The Netherlands
 

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Table of Contents
Page
PART I
 
Item 1.
Business..................................................................................................................................................................
3
Item 1A.
Risk Factors............................................................................................................................................................
47
Item 1B.
Unresolved Staff Comments...................................................................................................................................
97
Item 1C.
Cybersecurity..........................................................................................................................................................
97
Item 2.
Properties................................................................................................................................................................
98
Item 3.
Legal Proceedings...................................................................................................................................................
98
Item 4.
Mine Safety Disclosures.........................................................................................................................................
98
PART II
Item 5.
Market for Registrant’s Common Equity, Related Shareholder Matters and Issuer Purchases of Equity 
Securities ................................................................................................................................................................
99
Item 6.
[Reserved]...............................................................................................................................................................
99
Item 7.
Management’s Discussion and Analysis of Financial Condition and Results of Operations ................................
100
Item 7A.
Quantitative and Qualitative Disclosures About Market Risk ...............................................................................
109
Item 8.
Financial Statements and Supplementary Data ......................................................................................................
109
Item 9.
Changes in and Disagreements with Accountants on Accounting and Financial Disclosure ................................
109
Item 9A.
Controls and Procedures.........................................................................................................................................
110
Item 9B.
Other Information...................................................................................................................................................
110
Item 9C.
Disclosure Regarding Foreign Jurisdictions that Prevent Inspections ...................................................................
110
PART III
Item 10.
Directors, Executive Officers and Corporate Governance .....................................................................................
111
Item 11.
Executive Compensation ........................................................................................................................................
114
Item 12.
Security Ownership of Certain Beneficial Owners and Management and Related Shareholder Matters ..............
114
Item 13.
Certain Relationships and Related Transactions, and Director Independence.......................................................
114
Item 14.
Principal Accounting Fees and Services ................................................................................................................
114
PART IV
Item 15.
Exhibits, Financial Statement Schedules................................................................................................................
115
Item 16
Form 10-K Summary..............................................................................................................................................
118
 

1
CAUTIONARY NOTE REGARDING FORWARD-LOOKING STATEMENTS 
This Annual Report on Form 10-K contains forward-looking statements. All statements other than statements of historical facts 
contained in this Annual Report on Form 10-K are forward-looking statements. In some cases, you can identify forward-looking 
statements by terms such as “may,” “will,” “should,” “expect,” “plan,” “anticipate,” “could,” “intend,” “target,” “project,” 
“contemplate,” “believe,” “estimate,” “forecast,” “predict,” “potential” or “continue” or the negative of these terms or other similar 
expressions, although not all forward-looking statements contain these words. Forward-looking statements contained in this Annual 
Report on Form 10-K, include without limitation statements regarding our plans to develop and commercialize our product candidates, 
the timing of our ongoing or planned clinical trials, including with respect to anticipated clinical data readouts the timing of and our 
ability to obtain and maintain regulatory approvals, the clinical utility of our product candidates, our commercialization, marketing 
and manufacturing capabilities and strategy, our expectations surrounding our collaborations, our expectations about the willingness 
of healthcare professionals to use our product candidates, the sufficiency of our cash, cash equivalents and investments, and the plans 
and objectives of management for future operations and capital expenditures.
The forward-looking statements in this Annual Report on Form 10-K are only predictions and are based largely on our current 
expectations and projections about future events and financial trends that we believe may affect our business, financial condition and 
results of operations. These forward-looking statements speak only as of the date of this Annual Report on Form 10-K and are subject 
to a number of known and unknown risks, uncertainties and assumptions and other important factors, including those described under 
the sections in this Annual Report on Form 10-K entitled “Summary Risk Factors,” “Risk Factors” and “Management’s Discussion 
and Analysis of Financial Condition and Results of Operations” and elsewhere in this Annual Report on Form 10-K.
Because forward-looking statements are inherently subject to risks and uncertainties, some of which cannot be predicted or quantified 
and some of which are beyond our control, you should not rely on these forward-looking statements as predictions of future events. 
The events and circumstances reflected in our forward-looking statements may not be achieved or occur and actual results could differ 
materially from those projected in the forward-looking statements. Moreover, we operate in an evolving environment. New risk 
factors and uncertainties may emerge from time to time, and it is not possible for management to predict all risk factors and 
uncertainties. Except as required by applicable law, we do not plan to publicly update or revise any forward-looking statements 
contained herein, whether as a result of any new information, future events, changed circumstances or otherwise. We intend the 
forward-looking statements contained in this Annual Report on Form 10-K to be covered by the safe harbor provisions for forward-
looking statements contained in Section 27A of the Securities Act of 1933, as amended, or the Securities Act, and Section 21E of the 
Securities Exchange Act of 1934, as amended, or the Exchange Act. Additionally, certain information we may disclose (either herein 
or elsewhere) is informed by the expectations of various stakeholders or third-party frameworks and, as such, may not necessarily be 
material for purposes of our filings under U.S. federal securities laws, even if we use “material” or similar language in discussing such 
matters.
SUMMARY RISK FACTORS
Our business is subject to numerous risks and uncertainties, including those described in Part I, Item 1A. “Risk Factors” in this Annual 
Report on Form 10-K. You should carefully consider these risks and uncertainties when investing in our common shares. The 
principal risks and uncertainties affecting our business include the following:
 
•
We have incurred significant net losses since our inception and we expect to continue to incur significant expenses and 
operating losses for the foreseeable future.
•
We have a limited operating history, have limited experience with registrational clinical trials, and a single approved 
product planned for commercial sale through an exclusive licensee, which may make it difficult for you to evaluate our 
current business and predict our future success and viability. 
•
We will require substantial additional capital to finance our operations. If we are unable to raise such capital when needed, 
or on acceptable terms, we may be forced to delay, reduce or eliminate one or more of our research and drug development 
programs or future commercialization efforts.
•
The outcome of pre-clinical testing and early clinical trials may not be predictive of the success of later clinical trials, and 
the results of our clinical trials may not satisfy the requirements of the FDA, EMA or other comparable foreign regulatory 
authorities.
•
The clinical trial and regulatory approval processes are lengthy, time consuming, require compliance with extensive 
regulations and consistent with appropriate quality, and are inherently unpredictable, and we may incur additional costs or 
experience delays in completing, or ultimately be unable to complete, the development and commercialization of our 
product candidates or for our product approved under accelerated approval, we may be unable to meet the requirements 
for full approval, including potential verification and description of clinical benefit in confirmatory trial(s).

2
•
Our antibody candidates may have serious adverse, undesirable or unacceptable side effects alone or in combinations 
being tested in clinical development, which may delay or prevent marketing approval. If such side effects are identified 
during the development of our antibody candidates or following approval, if any, we may need to abandon our 
development of such antibody candidates, the commercial profile of any approved label may be limited, or we may be 
subject to other significant negative consequences following marketing approval, if any. 
•
We have never commercialized an antibody candidate before and may lack the necessary expertise, personnel and 
resources to successfully commercialize our products on our own or together with our exclusive licensee Partner 
Therapeutics for the commercialization of BIZENGRI® in the United States in the field of NRG1 fusion cancer .
•
We rely, and expect to continue to rely, on third parties, including independent clinical investigators and contract research 
organizations or CROs, to conduct our pre-clinical studies, clinical trials, chemistry, manufacturing and controls and 
potential development of a companion diagnostic. If these third parties do not successfully carry out their contractual 
duties, meet expected deadlines, perform with the requisite level of compliance and quality, or perform at reasonable cost, 
we may not be able to obtain regulatory approval for or commercialize our antibody candidates or we may be subject to 
other significant negative consequences following marketing approval for BIZENGRI®, and our business could be 
substantially harmed.
•
Due to our limited resources and access to capital, we must, and have in the past decided to, prioritize development of 
certain antibody candidates over other potential candidates. These decisions may prove to incorrect and may adversely 
affect our revenues.
•
The competition for qualified personnel is particularly intense in our industry. If we are unable to retain or hire key 
personnel, we may not be able to sustain or grow our business.
•
We operate in highly competitive and rapidly changing industries, and if our competitors develop and market technologies 
or products more rapidly than we do or that are more effective, safer or less expensive than the product candidates we 
develop, our commercial opportunities will be negatively impacted.
•
Our success depends on our ability to protect our intellectual property and our proprietary technologies. If we are unable 
to adequately protect our intellectual property and our proprietary technologies or obtain and maintain issued patents 
which are sufficient to protect our product candidates and proprietary technologies, or if others do not respect our 
intellectual property rights and exclusivity, others could compete against us more directly, which would negatively impact 
our business.
•
Our existing collaboration agreements are important to our business and potential future collaborations and licenses may 
also be important to us, and if we are unable to maintain any of these collaborations or execute new collaborations or 
licenses, or if these arrangements are not successful, our business could be adversely affected.
•
The trading prices for our and other biopharmaceutical companies’ shares have been highly volatile as a result of 
disruptions and extreme volatility in the global economy, including political changes in the United States, rising inflation 
and interest rates, declines in economic growth, global instability, including the ongoing conflicts in Europe and the 
Middle East, which have and may continue to adversely impact our business, including our pre-clinical studies and 
clinical trials, financial condition, our ability to raise capital and results of operations.

3
PART I
Item 1. Business.
Overview 
We are an oncology company developing innovative antibody therapeutics. Our pipeline of full-length, human, multispecific antibody 
candidates is generated from our proprietary technology platforms, which are able to generate a diverse array of antibody binding 
domains, or Fabs, against virtually any target. Our antibody binding domain generally consist of a target-specific heavy chain paired 
with a common light chain. Multiple binding domains can be combined to produce novel multispecific antibodies that bind to a wide 
range of targets and display novel and innovative biology. These platforms, referred to as Biclonics® and Triclonics®, allow us to 
generate large numbers of diverse panels of bispecific and trispecific antibodies (Multiclonics®), respectively, which can then be 
functionally screened in large-scale cell-based assays to identify those unique molecules that possess novel biology, which we believe 
are best suited for a given therapeutic application. Further, by binding to multiple targets, Biclonics® and Triclonics® may be designed 
to provide a variety of mechanisms of action, including simultaneously blocking receptors that drive tumor cell growth and survival 
and mobilizing the patient’s immune response by engaging T cells, and/or activating various killer cells to eradicate tumors. Our 
Multiclonics® are compatible with a range of linkers and payloads to generate antibody-drug conjugates (ADClonics®) capable of 
binding two or three different targets with the potential for improved binding selectivity, internalization and cancer cell killing 
activity. 
Our technology platforms employ an assortment of patented technologies and techniques to generate human antibodies. We utilize our 
patented MeMo® mouse to produce a host of antibodies with diverse heavy chains and a common light chain that are capable of 
binding to virtually any antigen target. We use our patented heavy chain and CH3 domain dimerization technology to generate 
substantially pure bispecific and trispecific antibodies. We also employ our patented Spleen to Screen® technology to efficiently 
screen panels of diverse heavy chains, designed to allow us to more rapidly identify Biclonics® and Triclonics® therapeutic 
candidates with differentiated modes of action for pre-clinical and clinical testing. 
Using our Biclonics® platform we have produced, and are currently developing, the following candidates: Petosemtamab (MCLA-
158) for the potential treatment of solid tumors and MCLA-129, for the potential treatment of lung and other solid tumors. The United 
States Food and Drug Administration (FDA) granted accelerated approval to BIZENGRI® (zenocutuzumab-zbco), the first and only 
treatment indicated for adults with either pancreatic adenocarcinoma or non–small cell lung cancer (NSCLC) that are advanced 
unresectable or metastatic and harbors a neuregulin 1 (NRG1) gene fusion who have disease progression on or after prior systemic 
therapy. Furthermore, we have a pipeline of proprietary antibody candidates in pre-clinical development and intend to further leverage 
our Biclonics® and Triclonics® technology platforms to identify multiple additional antibody candidates and advance them to clinical 
development. 
Our Strategy 
Our goal is to become a leading oncology company developing innovative multispecific antibodies to treat various types of cancer. 
Our business strategy comprises the following components:
•
Successfully develop our lead bispecific antibody candidate petosemtamab, MCLA-158. We are developing 
petosemtamab for a potential dual EGFR/LRG5 blockade for the treatment of solid tumors. Petosemtamab is currently 
being evaluated in two phase 3 registrational trials in recurrent or metastatic (r/m) head and neck squamous cell 
carcinoma (HNSCC). LiGeR-HN1 is a phase 3 study evaluating the efficacy and safety of petosemtamab in combination 
with pembrolizumab in 1L HNSCC expressing PD-L1 (CPS ≥ 1). In this trial, patients will be randomized to 
petosemtamab plus pembrolizumab or pembrolizumab monotherapy. LiGeR-HN2 is a phase 3 study evaluating the 
efficacy and safety of petosemtamab monotherapy in 2/3L HNSCC. In this trial, patients will be randomized to 
petosemtamab or investigator's choice of single agent chemotherapy or cetuximab. The expansion part of a phase 1/2 
open-label, multicenter trial evaluating petosemtamab monotherapy in patients with advanced solid tumors, including 
previously treated advanced r/m HNSCC and petosemtamab in combination with pembrolizumab in previously untreated 
r/m HNSCC expressing PD-L1 (CPS > 1) continues. In addition, we evaluated 56 patients with previously treated (2/3+L) 
HNSCC with petosemtamab monotherapy at the 1100 or 1500 mg dose levels to confirm a suitable dose for future 
potential randomized trials. Through feedback with the FDA we confirmed that petosemtamab 1500 mg every two weeks 
is appropriate for further development in HNSCC as monotherapy, and in combination with pembrolizumab in the 
LiGeR-HN2 and LiGeR-HN1 phase 3 studies respectively. We shared clinical data on petosemtamab monotherapy in 
patients with previously treated r/m HNSCC at the European Society for Medical Oncology (ESMO®) Asia Congress in 
December 2024. In February 2025, the U.S. Food and Drug Administration (FDA) granted Breakthrough Therapy 
designation (BTD) for petosemtamab in combination with pembrolizumab for the first-line treatment of adult patients 
with r/m programmed death-ligand 1 (PD-L1) positive HNSCC with CPS ≥ 1.  In May 2024, the FDA granted BTD for 
petosemtamab for the treatment of patients with r/m HNSCC whose disease has progressed following treatment with 

4
platinum based chemotherapy and an anti-programmed cell death receptor-1 (PD-1) or anti-programmed death ligand 1 
(PD-L1) antibody. This designation follows receipt of Fast Track designation for petosemtamab for the treatment of 
patients with r/m HNSCC whose disease has progressed following treatment with platinum-based chemotherapy and an 
anti-programmed cell death protein 1 (anti-PD-1) antibody announced in August 2023.  In July 2024, the first patient was 
dosed in a phase 2 trial evaluating petosemtamab in combination with standard chemotherapy in second line (2L) 
metastatic colorectal cancer (mCRC) and in December 2024 the first patient was dosed in a phase 2 trial evaluating 
petosemtamab monotherapy in heavily pretreated (3L+) mCRC. We have also started dosing patients in a cohort 
evaluated petosemtamab in combination with standard chemotherapy in 1L mCRC.
•
Successfully commercialize our most advanced bispecific antibody candidate, zenocutuzumab (Zeno), through our 
collaboration with Partner Therapeutics, indicated for adults with pancreatic adenocarcinoma or non-small cell lung 
cancer (NSCLC) that are advanced unresectable or metastatic and harbor a neuregulin 1 (NRG1) gene fusion who 
have disease progression on or after prior systemic therapy, and as we explore other potential indications in non-
NRG1 fusion cancers by targeting both HER2 and HER3. We developed our most advanced bispecific antibody 
candidate, Zeno, for the treatment of pancreatic adenocarcinoma or non-small cell lung cancer (NSCLC) that are 
advanced unresectable or metastatic and harbor a neuregulin 1 (NRG1) gene fusion who have disease progression on or 
after prior systemic therapy. The NRG1 protein is the ligand for the HER3 receptor—a known cause of cancer cell 
growth. The gene encoding NRG1 can form genetic rearrangements referred to as NRG1 gene fusions. The protein 
product of the NRG1 gene fusion can drive signaling through the HER3 receptor and thus drive cancer cell growth. NRG1 
gene fusions (NRG1+) occur infrequently in a wide range of different cancer types. Zeno has been shown pre-clinically to 
potently disrupt binding of NRG1 (and NRG1-fusion proteins) to HER3 and halt NRG1-stimulated tumor cell growth. In 
July 2020, the FDA granted Zeno orphan drug designation for the treatment of patients with pancreatic cancer and in 
January 2021, the FDA granted Fast Track designation to Zeno for the treatment of patients with metastatic solid tumors 
harboring NRG1 gene fusions that have progressed on standard-of-care therapy. In July, 2023, we announced that the 
FDA has granted Breakthrough Therapy designation (BTD) to Zeno for the treatment of patients with advanced 
unresectable or metastatic NRG1 fusion-positive (NRG1+) pancreatic cancer following progression with prior systemic 
therapy or who have no satisfactory alternative treatment options. Additionally, the FDA has granted BTD to Zeno for the 
treatment of patients with advanced unresectable or metastatic NRG1+ non-small cell lung cancer (NSCLC), following 
progression with prior systemic therapy. On December 4, 2024, the FDA approved BIZENGRI® (zenocutuzumab-zbco), 
the first and only treatment indicated for adults with pancreatic adenocarcinoma or NSCLC that are advanced 
unresectable or metastatic and harbor a NRG1 gene fusion who have disease progression on or after prior systemic 
therapy. These indications are approved under accelerated approval based on overall response rate (ORR) and duration of 
response (DOR). Continued approval for these indications may be contingent upon verification and description of clinical 
benefit in a confirmatory trial(s).In December 2024, we announced that the Company and Partner Therapeutics, 
Inc. (PTx), a private, fully-integrated biotechnology company with a focus in hematology and oncology, entered into an 
agreement in which Merus has exclusively licensed to PTx the right to commercialize zenocutuzumab (Zeno) for the 
treatment of NRG1 fusion-positive (NRG1+) cancer in the United States (U.S.). We continue to explore potential to 
develop Zeno outside of the field of NRG1 fusion cancer.
•
Successfully develop our bispecific antibody candidate MCLA-129. We are developing MCLA-129 as a potential 
treatment for solid tumors, including NSCLC. We presented a clinical update on MCLA-129  in NSCLC with hepatocyte 
growth factor receptor (c-MET) exon 14 skipping mutations (METex14) at the 2024 ASCO® Annual Meeting in June. We 
continue to follow patients with EGFRm NSCLC treated with MCLA-129 in combination with osimertinib, a third 
generation EGFR tyrosine kinase inhibitor, to evaluate potential for biomarkers as a means to maximize efficacy, while 
proactively addressing safety signals seen to date. Based on the results to date, we are encouraged by the potential for 
MCLA-129 in the treatment of cancer and are evaluating focused investment opportunities. We initiated cohorts evaluating 
MCLA-129 in combination with chemotherapy in 2L+ EGFRm NSCLC. We also remain interested in exploring partnering 
MCLA-129 with other companies to sufficiently resource the development of MCLA-129 and potential benefit it may have 
for patients. MCLA-129 is subject to a collaboration and license agreement between Merus and Betta Pharmaceuticals Co. 
Ltd. (Betta), whereby Merus exclusively licensed Betta to potentially commercialize MCLA-129 in China, while Merus 
retains full ex-China rights. 
•
Accelerate the discovery and development of additional internal and collaboration-related Multiclonics®, bispecific 
antibody candidates and trispecific antibody and multispecific, antibody drug conjugate (ADC), ADClonics® candidates. 
We believe we are well positioned to expand our pipeline of Biclonics® and Triclonics® molecules for the potential 
treatment of cancer and potentially other diseases. We are conducting pre-clinical studies for our internal proprietary 
bispecific and trispecific pipeline as well as leveraging our bispecific platform with our collaborators including Incyte, Eli 
Lilly and Company (Lilly), and Betta; leveraging our trispecific platform with our collaborator Gilead Sciences (Gilead); 

5
and leveraging our bispecific antibodies for the generation of bispecific ADCs through our collaboration with Biohaven 
Ltd. (Biohaven).
•
Seek strategic collaborations. We intend to seek strategic collaborations to facilitate the capital-efficient development of 
our pipeline and to maximize the value of our Biclonics® and Triclonics® and ADClonics® technology platforms and to 
access unique partner capabilities and capacity. We have entered into collaborations with Incyte, Lilly, and Betta to develop 
bispecific antibody candidates based on our Biclonics® technology platform. In March 2024 we entered into a collaboration 
with Gilead to develop trispecific T-cell engagers based on our Triclonics® technology platform. In January 2025, we 
entered into a collaboration with Biohaven to co-develop three novel bispecific ADCs, leveraging Merus’ 
Biclonics® technology platform, and Biohaven’s ADC conjugation and payload platform technologies. We plan to work 
with other potential future collaborators to further validate and expand the use of our Biclonics®, Triclonics® and 
ADClonics® platforms in developing bispecific and trispecific and multispecific ADC antibody candidates. We have also 
worked with Ono Pharmaceutical Co., Ltd., under a research license agreement to generate bispecific antibodies, including 
for indications in and outside oncology, which further underscore the breadth of the Merus platform. We believe these 
collaborations, license and future agreements could potentially provide significant funding to advance our pipeline and 
allow us to benefit from the additional resources, development and commercialization expertise of our collaborators. 
Our Biclonics® and Triclonics® Candidate Portfolio 
We currently have bispecific candidates in clinical development, with a variety bispecific and trispecific candidates in pre-clinical 
development. The following table summarizes our development candidate pipeline: 

6
There are also currently bispecific candidates in clinical development, which are subject to our collaboration and license agreements, 
for which we may be eligible to receive potential milestones and royalties, if approved:
Cancer Immunotherapeutics 
Immunotherapy is a class of cancer treatment that works to harness a patient’s own immune system to attack the cancer cells. There 
are a number of immunotherapies that are designed to engage various aspects of the immune system, for example: (1) adaptive 
immunity, specifically directing genetically modified T cells to the tumor with chimeric antigen receptor, or CAR T cells or T-cell 
receptor modification; or modulating T-cell activity through co-stimulation or checkpoint signals; and (2) innate immunity, including 
antibody-dependent cellular cytotoxicity (ADCC), cellular-dependent cytotoxicity (CDC), monocyte/macrophage cytotoxicity, natural 
killer (NK) cell cytotoxicity, or other forms of T-cell cytotoxicity; all directed at the cancer cells. While these therapies vary in 
mechanism of action, they rely on specific components of the innate or adaptive immune system to kill tumor cells or counteract 
signals produced by cancer cells that suppress immune responses.
While these approaches have advanced the field of oncology, each also have limitations. For example, the enhanced ADCC of 
monoclonal antibodies that bind to a single target expressed by tumor cells can potentially induce an autoimmune “on-target, off-
tumor” toxicity to normal non-tumor tissues that may also express the same target antigen. Cell-based therapies such as genetically 
modified CAR-T cells can be difficult and expensive to manufacture, can persist in patients for many months, can be associated with a 
toxic cytokine release syndrome as safety concerns, or can become ineffective if the tumor loses expression of the single antigen 
against which the CAR-T cells are directed. We believe multispecific antibody candidates developed from our novel platforms offer 
the potential to overcome these limitations.
Background on Antibodies 
The conventional antibody in full length immunoglobulin G (IgG) format is a Y-shaped molecule that consists of two identical heavy 
chains and two identical light chains, as shown in the figure below. Each heavy chain pairs with the light chain to form two variable 
regions, or antigen binding fragment, Fab, that bind to antigens, or targets, and a constant region, which includes a region known as 
the fragment crystallizable (Fc) that binds to receptors present on effector cells in the immune system. In conventional full-length IgG, 
the variable regions are identical and bind to the same targets.

7
In multispecific antibodies, the two or more variable regions bind to two or more different targets. To achieve this in the full-length 
IgG format, different heavy chain variable regions that can use a common light chain are combined. In addition, modifications of the 
heavy chain Fc regions are engineered to drive the formation of full-length IgG that use two different heavy chains rather than two 
copies of the same heavy chain, which make a monospecific antibody.
In both conventional monoclonal antibodies (mAbs) and IgG multispecific antibodies, the Fc region can bind to Fc receptors present 
on effector cells. This binding results in the recruitment and activation of immune effector cells and amplifies the immune system’s 
response to antigens bound by the variable region of the antibody. This process is called ADCC. The Fc region can be modified to 
enhance ADCC so as to generate a more potent immune response against a particular target. The Fc region can also be silenced to 
block interactions with the immune system.
Our Biclonics® and Triclonics® Platforms 
Our two technology platforms use large-scale functional screening in molecular and cell-based assays to identify novel, innovative 
Biclonics® and Triclonics® with the specific characteristics desired for further development.
We believe our Biclonics® and Triclonics® platforms allow us to approach cancer treatment through multiple innovative modes of 
action:
•
Blocking oncogenic growth factor signaling by disrupting the signaling pathways that drive tumor cell growth or 
resistance to monoclonal antibody therapy. This includes, for example tumor cell growth driven by NRG1 fusions 
interacting with the HER3 receptor. Hard-to-target receptors that may drive tumor growth or escape can be targeted by our 
Dock and Block® mechanism whereby the binding a tumor associated target prevalent on cancer cells facilitates a second 
domain to bind and block lesser expressed targets that are critical for cancer growth. 
•
Engaging an adaptive immune response by recruiting T-cells and/or modulating co-stimulation or checkpoint 
inhibition. We can produce multispecific antibodies that are designed to simultaneously bind to the T-cell antigen CD3 or 
other effector cell engaging antigens, and/or tumor-associated targets, for a potentially potent T cell or other effector cell 
recruitment and engagement to selectively kill tumor cells. 
•
Engaging the innate immune response through multiple mechanisms. We can produce enhanced ADCC modifications in 
the Fc region of our Biclonics® or Triclonics® designed to facilitate the recruitment of immune effector cells, such as 
natural killer cells, or NK cells, and macrophages, to directly kill tumor cells. Specific binding domains engineered in 
multispecific antibodies can directly bind to macrophages and monocytes; NK cells, each providing specific immune cell 
function to attack cancer cells. 
•
Employing combinations of the above mechanisms. Using our platforms, we can design antibodies to simultaneously 
target a growth factor receptor expressed by tumor cells and an immunomodulatory molecule involved in blocking and/or 
reactivating tumor-specific T cells. Biclonics® and Triclonics® can be designed to target growth factor receptors, like 

8
epidermal growth factor receptors (EGFR) and HER2 that are expressed on many tumors, while delivering an activation 
signal or checkpoint blockade to T cells. 
Our process to select lead Biclonics® for clinical development is illustrated below. We use our patented MeMo®, Spleen to Screen®\, 
heterodimerization technology, human antibody generation and production technologies to rapidly build large collections of 
Biclonics® or Triclonics® directed against particular target combinations. We then test these collections in cell-based functional assays 
to identify multispecific antibodies that have the potential for novel and innovative modes of action. We select the most potent or 
efficacious and evaluate them in multiple in vitro and in vivo assays to identify lead candidates for clinical development. 
Selection of Lead Multiclonics® 
Our Biclonics® technology platform includes the following:
Human antibody generation. One of our platforms for generating human antibodies employs our patented transgenic common light 
chain technology, which we refer to as MeMo®, harbors human heavy chain variable region gene segments and a human common 
light chain in its germline. MeMo® harnesses the power of the in vivo immune system to yield human antibodies with the potential for 
high affinity, specificity, optimal biophysical characteristics and low immunogenicity. Upon immunization, MeMo® is capable of 
generating large and diverse panels of human common light chain antibodies against a broad variety of targets. These human common 
light chain antibodies are then used to generate large and diverse panels of human multispecific antibodies capable of binding different 
targets of virtually any combination.

9
•
Patented dimerization technology and the full-length Immunoglobulin G format. Our Biclonics® consist of two different 
heavy chains that need to stably form, or heterodimerize, inside a manufacturing cell line. Using our patented dimerization 
technology, we employ amino acid residues with opposite charges in the CH3 domains of these heavy chains to efficiently 
drive the formation of the heterodimer bispecific antibody rather than the homodimer antibody consisting of two copies of 
the same heavy chain. In addition, the use of a single, or common, light chain in our human Biclonics® antibodies ensures 
that each heavy chain pairs with the correct, common light chain to efficiently form the intended functional antigen binding 
regions. The combination of these approaches prevents the need for additional, more artificial techniques, such as the use of 
linkers or chemical reactions, to force the pairing of different parts of the bispecific antibody. In addition, the format is 
designed to retain favorable attributes of conventional human IgG mAbs, including their stability and predictability during 
manufacturing as well as their long half-life and low immunogenicity during treatment of patients. The resulting Biclonics® 
are bispecific heterodimeric IgG antibodies that are designed to closely mimic IgG antibodies that are produced naturally by 
the immune system. 
The Biclonics® format also permits us to make modifications to the Fc region of the IgG antibody in order to enhance or limit effector 
functions associated with this part of the molecule. This strategy has been successfully executed with conventional therapeutic mAbs. 
In order to enhance efficacy and promote immunotherapeutic activity, we can use glycoengineered cell lines used in production to 
generate Biclonics® that are enhanced for ADCC, resulting in the improved ability to recruit NK cells and macrophages. This ADCC 
enhancement has been made to our approved bispecific antibody BIZENGRI® (zenocutuzumab-zbco), our lead antibody candidate, 
petosemtamab (MCLA-158) and to MCLA-129. In order to improve safety and tolerability, we can modify our Biclonics® to prevent 
the excessive release of signaling proteins called cytokines, which can overstimulate the immune system. This process is called Fc-
silencing, and is designed to block the ability of our Biclonics® to bind to certain protein receptors on cells, known as Fc receptors, 
which are associated with cytokine release.  
•
High-throughput functional screening. We employ our patented Spleen to Screen® technology to rapidly screen panels of 
new target-specific heavy chains that form common light chain binding domains, or we employ our already established 
panels of common light chain antibodies. To date we have discovered over 10,000 unique common light chain antibodies 
directed at more than 40 different antigens, including tumor-associated antigens such as EGFR and c-MET; T-cell binding, 
stimulating or co-stimulating proteins such as CD3 and CD137 (also called 4-1BB); and other immune-cell engaging 
antigens. For example, we have an established panel of more than 175 unique and novel anti-CD3 common light chain 
antibodies from which to discover and develop the next generation of T-cell engaging bispecific and trispecific antibodies. 
We then generate DNA constructs that encode target-specific human antibodies and express them in mammalian cells. The 
common light chain format and proprietary dimerization modifications to the CH3 domain of the IgG promote the secretion 
of virtually pure Biclonics® into the cell culture medium. The medium of thousands of cell cultures that each express a 
different Biclonics® is harvested and individually used in high throughput molecular and cell-based functional assays to 
identify Biclonics® with specific novel characteristics for further development. 
For example, the chart below shows the results of a pre-clinical study in which hundreds of different Biclonics® targeting HER2 and 
HER3 were functionally screened for cell growth inhibition of tumor cell samples in the presence or absence of the HER3 ligand 
NRG1. Forty of the Biclonics® depicted in the chart exhibited superior inhibition of cell growth compared to trastuzumab, a drug 
commonly prescribed for the treatment of breast cancer, and were selected in the process leading to identification of 
BIZENGRI® (zenocutuzumab-zbco). 

10
Advantages of Biclonics® 
We believe our Biclonics® technology platform provides the following advantages:
•
Rapid generation of human IgG antibodies having diversity at the heavy chain targeting an array of antigens, that are 
ready to be paired to produce our Biclonics®, bispecific antibodies. Use of our patented MeMo®, Spleen to Screen®, 
heterodimerization and Fc modification technologies, permits us to rapidly generate a large amount of diverse bispecific 
antibodies capable of targeting an array of antigen combinations. 
•
Biclonics® are stable, bispecific, full-length human IgG antibodies with no linkers or fusion proteins. Biclonics® retain 
the IgG format of antibodies that are produced naturally by the immune system. Additionally, in contrast to many other 
bispecific antibody formats, Biclonics® do not require linkers or modifications to force the correct pairing of heavy and 
light chain variable regions or exploit fusion proteins to add functionality to the molecule. These qualities minimize time-
consuming engineering efforts that can cause stability or developability obstacles, and instead allow us to create Biclonics® 
with more predictable behavior during development. 
•
Our Biclonics® technology platform allows for functional evaluation of Biclonics® in the relevant therapeutic format 
leading to the discovery of therapeutic candidates with novel and innovative properties. Our Biclonics® technology 
platform permits rapid functional screening of large collections of bispecific antibodies which allows us to identify lead 
candidates with multiple mechanisms of action that have the potential to effectively kill tumor cells with high potency. This 
is an important step in the identification of lead bispecific antibody candidates with functionalities that compare favorably 
against other forms of therapeutics, such as conventional mAbs as well as their combinations.
•
Biclonics® preserve the stability, behavior and adaptability of normal IgG antibodies. Biclonics® are based on the robust 
and commonly used IgG format to yield the favorable in vivo qualities associated with conventional mAbs, such as stability, 
long half-life and low immunogenicity. As a result, our Biclonics® format provides attractive options for dosage schedules 
and methods of administration, rendering them compatible with multiple modes of action for the efficient killing of tumor 
cells. Further, the IgG format allows us to apply previously established technologies to further optimize our Biclonics® for 
therapeutic use. 
•
Biclonics® can be reliably manufactured with high yields. Because our Biclonics® retain the IgG format of antibodies, our 
Biclonics® are manufactured using the large-scale industry-standard processes that are also used for the production of 
conventional mAbs, and the yields of Biclonics® we obtain are comparable to those of normal IgG antibodies. In stable cell 
lines, and using our IgG-based purification process can result in up to greater than 98% purity for our Biclonics®. 
Our Triclonics® Platform 
Our Triclonics® technology is covered by existing Merus patents and pending patent applications. This format, and the suite of 
technologies that underpin it, permit the development of therapeutic candidates designed to bind three targets with a single multivalent 
molecule. In pre-clinical studies and modeling, Triclonics® have shown similar qualities of a natural IgG antibody, including 
favorable half-life, stability, low immunogenicity and favorable developability characteristics. We believe Triclonics® have the 
potential to produce significant specificity and potency in tumor cell-killing activity and/or to modulate the immune system to promote 
more robust anti-tumor immune responses, and have the potential for less on-target off-tumor toxicity. This format allows us to 
leverage our proprietary genetically modified MeMo® mice, which as described above, harbor human heavy chain variable region 
gene segments and a human common light chain in its germline, as well as the use of other means of antibody production. MeMo® 
harnesses the power of the in vivo immune system to yield human antibodies with the potential for high affinity, specificity, optimal 
biophysical characteristics and low immunogenicity, which can be combined into a single trispecific antibody produced with relative 
high purity. The Triclonics® platform employs our proprietary technologies to produce large panels of substantially pure trispecific 
antibodies. In addition, we have engineered a panel of novel linkers that attach a third binding domain to the antibody. This panel of 
linkers vary in properties such as length and flexibility, and are empirically selected for stability and other drug-like properties, while 
remaining stable and are predicted to have low immunogenicity. The linker panel provides another lever of flexibility in optimizing 
functional characteristics in our high-throughput screening while maintaining high quality, stability and limiting risk of 
immunogenicity.

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One application of the Triclonics® platform is as a T-cell engager for solid tumors. By binding to three targets, we can generate 
Triclonics® designed to specifically engage a combination of two tumor antigens for enhanced specificity, binding preferentially to 
tumor cells expressing both antigens, over normal tissues that may express either antigen, but not both or both at lower expression 
levels. In this construct, the third binding domain can, for example, engage an innate or adaptive immune effector cell protein, to 
stimulate killing of the tumor cell. We believe our Triclonics® platform will permit us to develop molecules with enhanced on-target, 
on-tumor specificity, while optimally engaging the immune system mechanisms and potentially having greater potency and a larger 
therapeutic window.
 
Our process to select lead Triclonics® leverages our patented MeMo® and Spleen to Screen® human antibody generation and 
heterodimerization technologies, along with our proprietary linkers based on natural structures to undertake high throughput unbiased 
functional screening of Triclonics®. With this approach, we have been able to evaluate thousands of different trispecific antibodies 
targeting three different antigens to identify those unique combinations that pre-clinically have been observed to have desired 
characteristics for further development. 
Our ADClonics® Platform
Our ADClonics® technology is covered by existing Merus patents and pending patent applications. This format, and the suite of 
technologies that underpin it, permit the development of therapeutic candidates designed to bind two or more targets with a single 
multivalent molecule, which is compatible with a range of linkers and payloads to generate ADC-multispecific antibodies--
ADClonics®-- having the potential to be more selective and potent than conventional monoclonal ADCs. By selectively targeting 
multiple tumor associated antigens, ADClonics® hold the potential to use avidity binding and enhanced internalization to promote 
more robust anti-tumor responses, and have the potential for less on-target off-tumor toxicity. Merus is currently exploring this 
potential in a three program collaboration with Biohaven,which has multiple linker and payload technologies available for 
combination with Merus bispecific antibody candidates.

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Our Bispecific and Trispecific Antibody Candidate Portfolio 
We currently have three bispecific antibody candidates in clinical development, with additional bispecific and trispecific programs in 
pre-clinical development. 
Petosemtamab (MCLA-158, EGFR x LGR5 Biclonics®)
Petosemtamab is an investigational antibody-dependent cell-mediated cytotoxicity (ADCC)-enhanced Biclonics® for the potential 
treatment of solid tumors that is designed to bind to cancer stem cells expressing EGFR and leucine-rich repeat-containing G protein-
coupled receptor 5 (LGR5). EGFR is a member of the HER family of receptor tyrosine kinases and is important for growth and 
survival of cancer stem cells, including those with RAS mutations, while LGR5 is a WNT target gene expressed in cancer cells with 
aberrations in the WNT signaling pathway and reported to be up regulated in a variety of cancers including HNSCC, gastric cancer, 
NSCLC, colorectal cancer (CRC) and hepatocellular carcinoma (HCC). Petosemtamab is designed to exhibit three independent 
mechanisms of action including inhibition of EGFR-associated signaling, LGR5 binding leading to EGFR internalization and 
degradation in cancer cells, and enhanced ADCC and antibody-dependent cellular phagocytosis (ADCP) activity.
Development
In our pre-clinical studies, petosemtamab demonstrated superior growth inhibition and selectivity versus the EGFR-targeting mAb, 
cetuximab. Petosemtamab was significantly more potent than cetuximab in inhibiting the growth of patient-derived CRC organoids. 
Additionally, petosemtamab was observed to be selectively more active in human tumor-derived organoids than in organoids derived 
from normal human colon. The activity of petosemtamab on the tumor organoid size was more than 100 times greater than on the 
normal colon organoids. In contrast, the activity of cetuximab was similar to the activity of petosemtamab on normal colon organoids 
and 20 to 100 times less than the activity of petosemtamab on tumor organoids. These ex-vivo observations of petosemtamab with 
organoid models were further observed in vivo in xenograft models generated from the same patient-derived organoids.

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In our pre-clinical studies, petosemtamab further demonstrated significant induction of internalization of EGFR and LGR5, resulting 
in EGFR degradation, and elicited potential anti-tumor activity in patient-derived esophageal, gastric and HNSCC xenograft models.

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•
Solid Tumors
Petosemtamab  evaluation is ongoing in a phase 1/2 open-label, multicenter study, in the expansion phase, in patients with solid 
tumors, including previously treated r/m HNSCC, in combination with pembrolizumab, a PD-1blocking antibody, in previously 
untreated r/m HNSCC expressing PD-L1 (CPS > 0), in combination with standard chemotherapy in 1L and 2L mCRC and as 
monotherapy in 3L+ mCRC.  
The recommended phase 2 dose was established at 1500 mg administered intravenously once every two weeks and through feedback 
with the FDA we confirmed that petosemtamab 1500 mg every two weeks is appropriate for further development in the LiGeR-HN2 
and LiGeR-HN1 phase 3 studies, of 2/3L HNSCC as monotherapy, and 1L PD-L1+ HNSCC in combination with pembrolizumab, 
respectively.
In June 2024 we provided an interim clinical data  from the ongoing  phase 1/2 trial of petosemtamab with pembrolizumab in 1L 
PDL1+ r/m HNSCC at the 2024 ASCO® Annual Meeting. As of a March 6, 2024 data cutoff, 45 patients (pts) were treated. The 
efficacy population consisted of 4 pts who had been treated by November 6, 2023, who had the opportunity for 4 or more months 
follow up, with ≥2 treatment cycles and ≥1 post-baseline tumor assessment; or who discontinued early due to disease progression or 
death. Two pts were not included: One pt withdrew consent prior to first tumor assessment and the other pt discontinued due to 
toxicity with less than 2 cycles of treatment. The response rate overall (N=24) was 67%, including 1 confirmed complete response 
(CR), 12 confirmed partial responses (PRs) and 3 unconfirmed PRs (all of whom confirmed after the data cutoff) by Response 
Evaluation Criteria in Solid Tumors (RECIST) v1.1. per investigator assessment. Responses were observed regardless of HPV status, 
3 of 4 pts with HPV associated cancer responded, and across PD-L1+ levels treated (CPS 1-19: 60% [6/10]; CPS ≥ 20: 71% [10/14]). 
At the time of data cutoff, 32 pts of the 45 enrolled, remained on treatment, including 14 of 16 responders and 18 of the initial 26 pts 
enrolled. For the 45 pts treated median follow up was 3.6 months.The combination was well tolerated and no significant overlapping 
toxicities with pembrolizumab were observed and treatment-emergent adverse events (AEs) were reported in 45 pts. Most were Grade 
(G) 1 or 2 in severity (no G4–5 were observed). Infusion-related reactions (IRRs) (composite term) were reported in 38% (all Gs) and 
7% (G3) of pts, most occurred during the first infusion and resolved. We plan to provide updated efficacy, durability and safety data 
from this cohort in the first half of 2025.
Initial safety and efficacy data from this single arm cohort supported the initiation of a PD-L1+ HNSCC first-line registration trial 
which began in September 2024. The phase 3 trial, referred to as LiGeR-HN1, is evaluating the efficacy and safety of petosemtamab 
in combination with pembrolizumab, compared to pembrolizumab as 1L therapy for pts with PD-L1+ r/m HNSCC. We believe a 
randomized registration trial in HNSCC with an overall response rate endpoint could potentially support accelerated approval and the 
overall survival results from the same study could potentially verify its clinical benefit to support regulatory approval. 
In February 2025, the U.S. Food and Drug Administration (FDA) granted Breakthrough Therapy designation (BTD) for 
petosemtamab in combination with pembrolizumab for the first-line treatment of adult patients with r/m PD-L1 positive HNSCC with 
CPS ≥ 1.

15
In December 2024 at ESMO® Asia, we presented updated clinical data from the ongoing phase 1/2 trial of petosemtamab in 
previously treated HNSCC, previously presented at the American Association of Cancer Research (AACR) Annual Meeting 2023, 
in Orlando, Florida. This presentation also included clinical data from the dose optimization cohort evaluating petosemtamab 
monotherapy 1500 or 1100 mg dose levels in 2L+ HNSCC. As of the July 5, 2024 data cutoff date, 82 previously treated HNSCC pts 
were treated with petosemtamab 1500 mg intravenously every two weeks. The efficacy population consists of 75 pts who had the 
opportunity for 4 or more months follow up and ≥1 post-baseline tumor assessment; or who discontinued early due to 
disease progression or death. Seven pts were not efficacy evaluable: 6 pts previously described at AACR 2023 (5 pts withdrew due to 
IRR on day 1 and 1 pt with exclusion criteria deviation) and 1 additional pt withdrew due to IRR on day 1. Confirmed overall 
response rate (ORR) was 36% (90% CI: 27–46; 27/75) by RECIST v1.1. per investigator assessment, including 4 CRs, with one CR 
continuing on treatment for more than 3 years as of the data cutoff. Responses were also reported in HPV associated cancer, ORR was 
13% (2/15) and 5 additional pts achieved stable disease. At the time of data cutoff, 10 pts remained on treatment including 8 
responders and 2 pts with stable disease. Median duration of response (DOR), progression free survival (PFS) and overall survival 
(OS) were 6.2, 4.9 and 11.4 months. For the most mature data set, the single arm cohort previously presented at AACR 2023, as of 
a July 5, 2024 data cutoff, for all 54 patients, the median DOR, PFS and OS were 6.7, 5.1, and 12.0 months, respectively and among 
the 48 treatment evaluable subset, they were 6.7, 5.2, and 12.5 months, respectively. In 82 pts, petosemtamab 1500 mg every two 
weeks continued to be well tolerated with a manageable safety profile with no new safety signals observed. IRRs were predominantly 
seen on day 1 of cycle 1 and a clinically meaningful reduction in the incidence and severity of IRR was observed with an updated 
administration regimen compared to that used as of the 2023 AACR presentation. 
In July 2024, we initiated a randomized phase 3 trial, referred to as LiGeR-HN2, evaluating the efficacy and safety of petosemtamab 
compared to investigator’s choice of single agent chemotherapy or cetuximab in previously treated (2/3L) pts with r/m HNSCC. We 
believe a randomized registration trial in HNSCC with an overall response rate endpoint could potentially support accelerated 
approval and the overall survival results from the same study could potentially verify its clinical benefit to support regulatory 
approval. 

16
In May 2024, FDA has granted BTD for petosemtamab for the treatment of patients with r/m HNSCC whose disease has progressed 
following treatment with platinum based chemotherapy and an anti-programmed cell death receptor-1 (PD-1) or anti-programmed 
death ligand 1 (PD-L1) antibody. This designation follows receipt of Fast Track designation for petosemtamab for the treatment of 
patients with r/m HNSCC whose disease has progressed following treatment with platinum-based chemotherapy and an anti-
programmed cell death protein 1 (anti-PD-1) antibody announced in August 2023.
In July 2024, the first patient was dosed in a phase 2 trial evaluating petosemtamab in combination with standard chemotherapy in 
2L mCRC and in December 2024 the first patient was dosed in a phase 2 trial evaluating petosemtamab monotherapy in 3L+ mCRC. 
We have also starting dosing patients in a cohort to evaluate petosemtamab in combination with standard chemotherapy in 1L 
mCRC. We plan to share initial clinical data on petosemtamab in mCRC in the second half of 2025. 
Zenocutuzumab (Zeno, MCLA-128, HER2 x HER3 Biclonics®)
Zeno is an antibody-dependent cell-mediated cytotoxicity (ADCC)-enhanced Biclonics® that utilizes Merus’ Dock & Block® 
mechanism to bind to HER2, and bind to and disrupt the interaction between HER3 and ligand, neuregulin (NRG1) or mutated form 
NRG1 fusion, in solid tumors. HER2, or human epidermal growth factor receptor 2, is amplified in many solid tumors and is 
associated with poor prognosis, and the activation of HER3, or human epidermal growth factor receptor 3, is associated with tumor 
progression and treatment resistance. On the surface of tumor cells, HER2 pairs, or dimerizes, with HER3, and the resulting pair 
drives malignant progression of HER2-expressing cancer cells. NRG1, which is the ligand for HER3, causes cancer cells to grow and 
become resistant to treatment with HER2-targeted therapies. Zeno is believed to target the HER3 signaling pathway by disrupting the 
interaction of HER3 with its ligand NRG1 and to overcome the resistance of tumor cells to HER2-targeted therapies using two 
mechanisms: blocking growth and survival pathways to stop tumor expansion and recruitment, and ADCC-enhanced elimination of 
the tumor via effector cells. In addition, we have identified a rare, genetically defined patient population whose cancers harbor NRG1 
fusions. The NRG1 gene encodes for neuregulin, the ligand for HER3. Fusions between NRG1 and other genes in the genome are rare 
genetic events occurring in solid tumors, and are associated with activation of HER2/HER3 signaling and growth of cancer cells. The 
NRG1 fusion is a powerful driver of cancer cell growth. We believe that pre-clinical studies and clinical evaluation indicate Zeno 
(binding to HER2 and blocking NRG1 fusion protein interaction with HER3) has the potential to be particularly effective against 
tumors harboring NRG1 fusions. 

17
Development
In our pre-clinical studies, the administration of Zeno resulted in the inhibition of NRG-induced growth in cultures of cancer cells. 
Zeno also blocked activation of two key signaling pathways for the growth and survival of tumor cells more than Herceptin 
(trastuzumab) or the combination of Herceptin and Perjeta (pertuzumab) (shown in red below) or experimental anti-HER3 mAbs 
(shown in green below). See Geuijen et al. Cancer Cell (2018). 
* indicates analog antibodies.
In a patient-derived tumor xenograft mouse model (PDX model), Zeno significantly blocked tumor growth of a cancer containing an 
NRG1 gene fusion.

18
Based on encouraging pre-clinical results, we initiated a phase 1/2 study of Zeno in solid tumors. 
•
NRG1 Fusions and other potential cancers through targeting HER2 and HER3
In July 2020, Zeno was granted orphan drug designation by the FDA for the treatment of pancreatic cancer and in January 2021, we 
announced that Zeno received Fast Track designation for the treatment of patients with metastatic solid tumors harboring NRG1 gene 
fusions that have progressed on standard-of-care therapy.  
In June and July 2023, we announced that the FDA has granted BTD to Zeno for the treatment of patients with advanced unresectable 
or metastatic NRG1+ pancreatic cancer following progression with prior systemic therapy or who have no satisfactory alternative 
treatment options. Additionally, the FDA has granted BTD to Zeno for the treatment of patients with advanced unresectable or 
metastatic NRG1+ NSCLC, following progression with prior systemic therapy.
 
In March 2024 the FDA accepted for priority review a Biologics License Application (BLA) for Zeno in patients with NRG1+ 
NSCLC and NRG1+ PDAC. In December 2024, the FDA approved BIZENGRI® (zenocutuzumab-zbco), the first and only treatment 
indicated for adults with pancreatic adenocarcinoma or NSCLC that are advanced unresectable or metastatic and harbor a neuregulin 1 
(NRG1) gene fusion who have disease progression on or after prior systemic therapy. These indications are approved under 
accelerated approval based on overall response rate (ORR) and duration of response (DOR). Continued approval for these indications 
may be contingent upon verification and description of clinical benefit in a confirmatory trial(s). 
In December 2024, we announced a License Agreement with Partner Therapeutics (PTx) in which we have exclusively licensed to 
PTx the right to commercialize BIZENGRI® (zenocutuzumab-zbco) for the treatment of NRG1+ cancer in the United States. Under 
the terms of the agreement, following a specified transition period, PTx will assume full rights to U.S. commercialization of 
BIZENGRI® (zenocutuzumab-zbco) for the treatment of NRG1+ cancer. In exchange for the rights granted under the license 
agreement, Merus received an upfront payment and is eligible to receive milestones and high single-digit to low double-digit royalty 
payments based on the annual net sales of BIZENGRI® (zenocutuzumab-zbco) in NRG1+ cancer in the U.S. for any potential future 
sales.
We continue to explore development opportunities for Zeno outside the field NRG1 fusion cancer.
MCLA-129 (EGFR x c-MET Biclonics®)
MCLA-129 is an investigational Biclonics®, designed to bind EGFR and c-MET, for the potential treatment of solid tumors. EGFR is 
an important oncogenic driver in many cancers. The upregulation of c-MET signaling has been associated with resistance to EGFR 
inhibition. MCLA-129 has two distinct mechanisms of action. First, MCLA-129 is designed to block the signaling of EGFR as well as 
c-MET, in an effort to inhibit tumor growth and survival. Second, MCLA-129 utilizes ADCC-enhancement technology, which is 
designed for greater cell-killing potential. 

19
MCLA-129 is being developed in collaboration with Betta Pharmaceuticals Co. Ltd. (Betta). Under the terms of the collaboration, 
Betta is responsible for the clinical development and commercialization of MCLA-129, if approved, in China and we retain all rights 
to MCLA-129 outside of China. In January 2021, Betta announced that the Chinese National Medical Products Administration had 
accepted its Investigational New Drug application (IND) for MCLA-129 injection and in October 2021, Betta announced that the first 
patient was dosed in Betta’s sponsored phase 1/2 trial of MCLA-129 in China in patients with advanced solid tumors.
Development
Pre-clinical data on MCLA-129 were presented in October 2019, at the AACR-NCI-EORTC International Conference on Molecular 
Targets and Cancer Therapeutics. The poster, entitled “Pre-clinical evaluation of MCLA-129: a bispecific antibody targeting c-MET 
and EGFR,” showed that MCLA-129 inhibited and reversed resistance to tyrosine kinase resistant NSCLC, cell lines resulting in 
tumor growth inhibition in xenograft models of NSCLC. In these xenograft models, MCLA-129 showed tumor shrinkage in mice 
whose tumors are resistant to the EGFR small molecule inhibitor erlotinib. 
MCLA-129 Inhibited TKI Resistant NSCLC
|
MCLA-129 Reversed Acquired TKI Resistance
 
We believe these pre-clinical data suggest MCLA-129, if successfully developed and approved, could benefit patients having NSCLC 
that become resistant to EGFR targeted therapies. 
•
Solid Tumors
We are developing MCLA-129 as a potential treatment for solid tumors, including NSCLC. We presented a clinical update on MCLA-
129 from an ongoing expansion cohorts in NSCLC with c-MET exon 14 skipping mutations (METex14) at 2024 ASCO® Annual 
meeting. 
As of a February 16, 2024 data cutoff date, 22 patients (pts) were treated and 14 pts (64%) were continuing treatment. Each pt treated 
received MCLA-129 1500 mg, every 2 weeks. Pts had received a median two lines of prior therapy. Ten pts (45%) were tyrosine 
kinase inhibitor (TKI)-naïve and 12 (55%) had received prior TKIs. Seven pts were excluded from the efficacy population. Four 
discontinued due to AEs with <2 cycles of treatment and did not experience progressive disease while on study; 3 were ongoing as of 
the cutoff date with <2 treatment cycles. Fifteen pts were evaluable for response having received ≥2 treatment cycles, measurable 
disease at baseline and ≥1 post-baseline scan. The Response rate overall was 53% (8/15 confirmed PRs): 3 PRs and 6 unconfirmed 
PRs (uPRs) were observed by RECIST v1.1 per investigator assessment; 5 of the 6 uPRs were confirmed and 1 uPR progressed after 
the data cutoff. Six of 8 TKI-naïve cancers responded, one of which was an initial uPR that progressed after data cutoff. Three of 7 
cancers with prior MET TKI responded. Reduction in target lesion tumor size from baseline was demonstrated in 12 pts (80%). In 22 
pts treated, the early safety assessment included: IRRs in 86% ((18% ≥ Grade (G)3), one pt had treatment-related interstitial lung 
disease (G2) and venous thromboembolism was recorded in 2 pts (1 G3 possibly treatment-related, the other G2 and not related to 
treatment).

20
 
 
In EGFRm NSCLC, with the strong clinical activity for MCLA-129 shown in the interim data, we are encouraged by the potential for 
MCLA-129 in the treatment of lung cancer and beyond. We have identified focused investment opportunities. We continue to follow 
patients with EGFRm NSCLC treated with MCLA-129 in combination with osimertinib, to evaluate potential for biomarkers as a 
means to maximize efficacy, while proactively addressing safety signals seen to date.  
 We also remain interested in exploring partnering MCLA-129 with other companies to sufficiently resource the development of 
MCLA-129 and potential benefit it may have for patients. 
We initiated cohorts of MCLA-129 in combination with chemotherapy in 2L+ EGFRm NSCLC in 2024.    
Pre-clinical Discovery Programs
We intend to further leverage our Biclonics® , Triclonics® and ADClonics® technology platforms to identify multiple additional 
antibody candidates and advance them to clinical development. Each of these antibody candidates are designed to bind to targets 
believed to be useful in the treatment of cancer with an intention to establish efficacy and obtain information for submission to the 
FDA. Using our patented platforms, we will continue to evaluate new targets and combinations to identify potential candidates with 
the highest therapeutic potential and select those candidates to be advanced into clinical trials.
Collaboration Agreements
As part of our business strategy, we collaborate with a range of partners, including pharmaceutical, biotechnology, and diagnostic 
companies, as well as academic institutions. We intend to continue to seek collaborations and license agreements to develop and 
commercialize therapeutics in order to exploit the potential of our Biclonics®, Triclonics® and ADClonics® technology platforms. 
Incyte Corporation 
We have entered into a collaboration and license agreement (Incyte Collaboration Agreement) with Incyte Corporation (Incyte). 
Under the terms of the Incyte Collaboration Agreement, we and Incyte have agreed to collaborate with respect to the research, 
discovery and development of monospecific or bispecific antibodies utilizing our proprietary Biclonics® technology platform. 
Following the election by Incyte to opt-out of its ex-U.S. development of MCLA-145, discussed below, and to terminate a second 
program that achieved Program Selection, the collaboration encompasses up to nine independent programs. 
We have the option to co-fund development of products, if any, arising from one specified program, and subject to certain conditions, 
to a second specified program, in each case in exchange for a share of profits in the United States, as well as the right to participate in 
a specified proportion of detailing activities in the United States for one of such programs. If we exercise our co-funding option for a 
program, we would be responsible for funding 35% of the associated future global development costs and, for certain of such 
programs, would be responsible for reimbursing Incyte for certain development costs incurred prior to the option exercise. All 

21
products as to which we have exercised our option to co-fund development would be subject to joint development plans and overseen 
by a joint development committee, with Incyte having final determination as to such plans in cases of dispute. 
For one of our prior clinical programs, concerning MCLA-145, under the Incyte Collaboration Agreement, Incyte had received the 
exclusive right to develop and commercialize the product candidate outside the United States. In January 2022, we announced that 
Incyte elected to opt-out of its ex-U.S. development of MCLA-145, restoring full global rights to Merus. Under the terms of the Incyte 
Collaboration Agreement, Incyte supported the program for a limited time while ex-U.S. activities transitioned to Merus. Incyte 
retains a right to a residual royalty of up to 4% on sales of future commercialization of MCLA-145, if approved. Merus is no longer 
actively pursuing this program in the clinic, and is investigating potential collaboration opportunities to further investigate this 
antibody candidate.
For each program, where we have not elected to co-fund development or where we do not have such a co-funding option and which 
has not been dropped or terminated by Incyte, Incyte is solely responsible for all costs of global development and commercialization 
activities. We retain the rights to, among other things, our Biclonics® technology platform as well as clinical and pre-clinical 
candidates and future programs emerging from our platform that are outside the scope of the Incyte Collaboration Agreement. 
In January 2017, upon the Incyte Collaboration Agreement becoming effective, Incyte made an upfront non-refundable payment to us 
of $120 million for the rights granted under the Incyte Collaboration Agreement. For each program as to which we do not have 
commercialization or co-development rights, we are eligible to receive up to $100 million in future contingent development and 
regulatory milestones and up to $250 million in commercialization milestones, as well as tiered royalties ranging from 6% to 10% of 
global net sales. For each program as to which we have exercised our option to co-fund development, we are eligible to receive a 50% 
share of profits (or sustain 50% of any losses) in the United States and tiered royalties ranging from 6% to 10% of net sales of 
products outside of the United States. If we opt to cease co-funding a program as to which we exercised our co-development option, 
then we will no longer receive a share of profits in the United States but will be eligible to receive the same milestones from the co-
funding termination date and the same tiered royalties described above with respect to non-co-developed programs and, depending on 
the stage at which we choose to cease co-funding development costs, additional royalties ranging up to 4% of net sales in the United 
States. 
The Incyte Collaboration Agreement will continue on a program-by-program basis until neither party has any royalty payment 
obligations with respect to such program or, if earlier, the termination of the Incyte Collaboration Agreement or any program in 
accordance with the terms of the Incyte Collaboration Agreement. The Incyte Collaboration Agreement may be terminated in its 
entirety, or on a program-by-program basis, by Incyte for convenience. The Incyte Collaboration Agreement may also be terminated 
by either party under certain other circumstances, including material breach, or on a program-by-program basis for patent challenge of 
patents under the applicable program, in each case as set forth in the Incyte Collaboration Agreement. If the Incyte Collaboration 
Agreement is terminated in its entirety or with respect to one or more programs, all rights in the terminated programs revert to us, 
subject to payment to Incyte of a reverse royalty of up to 4% on sales of future products, if we elect to pursue development and 
commercialization of products arising from the terminated programs. 
In connection with the Incyte Collaboration Agreement, we entered into a share subscription agreement (Incyte Share Subscription 
Agreement) with Incyte, pursuant to which, in January 2017, we issued and sold to Incyte 3,200,000 common shares for an aggregate 
purchase price of $80.0 million. Incyte subsequently sold all shares purchased under the Incyte Share Subscription Agreement in 
2024.
Eli Lilly and Company (Eli Lilly)
In 2021, we entered into a collaboration and license agreement (the Lilly Collaboration Agreement) and share subscription agreement 
(the Lilly Subscription Agreement) with Eli Lilly and Company, an Indiana corporation (Eli Lilly).
Under the terms of the Lilly Collaboration Agreement, we and Eli Lilly agreed to collaborate with respect to the discovery and 
research of bispecific antibodies utilizing our proprietary Biclonics® bispecific technology platform. The collaboration encompasses 
up to three (3) independent programs directed to the generation of T-cell re-directing bispecific antibodies that bind CD3 and a tumor 
associated antigen target selected by Eli Lilly (Target) to be the subject of each such program.
We granted to Eli Lilly an exclusive, worldwide, royalty-bearing, sublicensable license, under certain patent rights and know-how to 
exploit certain compounds and products directed to designated Targets in combination with CD3, or directed to such designated 
Target(s) alone as a monospecific antibody or monospecific antibody drug conjugate, subject to rights granted by us to third parties 
under one or more existing third-party agreements. We also retain all rights not granted to Eli Lilly.
Additionally, in the case of a change of control that may adversely impact certain rights and obligations of us and Eli Lilly under the 
Lilly Collaboration Agreement, (a) we have agreed to terminate or transfer its rights to third parties under certain research programs 
and (b) Eli Lilly has the option to take over certain of our research obligations.
Eli Lilly paid an upfront, non-refundable payment of $40 million for the rights granted under the Lilly Collaboration Agreement. Eli 
Lilly agreed to fund the research and development activities we conduct for each program under an agreed research plan and budget. 
With respect to each product arising from each program, we are eligible to receive up to $290 million in future contingent 
development and regulatory milestones and up to $250 million in commercial sales milestones, for a total of up to approximately $1.6 
billion for a single product generated from all three programs. We are further eligible to receive, on a product-by-product and country-

22
by-country basis, tiered royalties based on the level of worldwide aggregate annual net sales at percentages ranging from the mid-
single digits to low double digits until the royalty term expires.
The Lilly Collaboration Agreement includes a three-year research term for us to perform research and development activities, subject 
to two extension terms of six months at Eli Lilly’s discretion, which Eli Lilly had exercised. The Lilly Collaboration Agreement will 
continue on a product-by-product basis until Eli Lilly has no royalty payment obligations with respect to such product or, if earlier, the 
termination of the Lilly Collaboration Agreement or any program in accordance with the terms of the Lilly Collaboration Agreement. 
The Lilly Collaboration Agreement may be terminated in its entirety or on a program-by-program basis at will by Eli Lilly. The Lilly 
Collaboration Agreement may also be terminated by either us or Eli Lilly under certain other circumstances, including material 
breach, as set forth in the Lilly Collaboration Agreement. If the Lilly Collaboration Agreement is terminated with respect to one or 
more programs, depending on the stage of development, certain rights in the terminated programs revert to us, in accordance with the 
terms of the Lilly Collaboration Agreement.
Also in January 2021, in connection with entering into the Lilly Collaboration Agreement, pursuant to the Lilly Subscription 
Agreement, Eli Lilly agreed to purchase 706,834 common shares of the Company at a price per share of $28.295 for aggregate gross 
proceeds to us of approximately $20 million.  As of February 2025, the discovery and research of bispecific antibodies utilizing our 
proprietary Biclonics® bispecific technology platform has concluded, with Eli Lilly advancing three (3) independent programs 
directed to the generation of T-cell re-directing bispecific antibodies that bind CD3 for further development.
Ono Pharmaceutical Co., Ltd.
In April 2014, we entered into a strategic research and license agreement with Ono, under which we granted Ono an exclusive, 
worldwide, royalty-bearing license to research, test, make, use and market a limited set of bispecific antibody candidates, if approved, 
based on our Biclonics® technology platform, directed to two undisclosed targets.
Ono paid us a non-refundable upfront fee of €1.0 million, and we are eligible to receive up to an aggregate of €57.0 million in 
milestone payments upon achievement of specified research and clinical development milestones. For products commercialized under 
this agreement, if any, we are also eligible to receive a mid-single digit royalty on net sales. For a designated period, which may 
include limited time periods following termination of this agreement, in certain circumstances we and our affiliates are prohibited 
from researching, developing or commercializing bispecific antibodies against the target combination that are the subject of this 
agreement. Ono also provides funding for our research and development activities under an agreed-upon plan. This research and 
license agreement will expire after all milestone payments have been received and all related patent rights have expired, unless 
terminated earlier. Ono has the right to terminate this agreement at any time for any reason, with or without cause. The licenses 
granted to Ono may convert to royalty-free, fully-paid, perpetual licenses if Ono terminates the agreement for uncured material 
breach. We retain all rights to use and commercialize any antibodies directed to one target utilized under the collaborative research 
program, and any antibodies directed to the second target developed under the collaborative research program, excluding the up to five 
lead and/or selected antibodies against the second target Ono is pursuing, provided that the use and commercialization is not with 
respect to the particular target combination. To date, we have achieved five of the specified milestones under this research and license 
agreement and have received an aggregate of €4.7 million in milestone payments.
On March 14, 2018, we entered into a second contract research and license agreement with Ono. Pursuant to an exclusive option 
granted to Ono in the prior agreement executed in April 2014, Ono exercised its option to enter into the March 2018 agreement. We 
granted Ono an exclusive, worldwide, royalty-bearing license, with the right to sublicense, research, test, make, use and market 
bispecific antibody candidates based on our Biclonics® technology platform against two undisclosed targets directed to a particular 
undisclosed target combination. Ono identifies and selects the licensed bispecific antibodies for which it is responsible for conducting 
further non-clinical and clinical development activities for such licensed bispecific antibodies and pharmaceutical products containing 
such antibodies, including manufacture and process development. Ono controls and has exclusive rights over the worldwide 
commercialization of any approved products, including worldwide supply, and is solely responsible for all costs and expenses related 
to commercialization. Ono has agreed to fund our research and development activities and be responsible for the payment of all costs 
and expenses for its own research and development activities, which are set out in a mutually agreed upon research plan. We retain all 
rights to use and commercialize any antibodies that are generated under the collaborative research program, excluding the up to five 
lead and/or selected antibodies against the targets Ono is pursuing, provided that the use and commercialization is not with respect to 
the particular target combination.
As part of the 2018 agreement, Ono agreed to pay an upfront non-refundable payment of €0.7 million for the rights granted and we are 
also eligible to receive an additional aggregate of €57.0 million in milestone payments upon achievement of specified research and 
clinical development milestones. In the fourth quarter of 2022, Merus achieved a milestone payment of €1.0 million from Ono for 
preclinical advancement of a lead candidate arising from this license. To date, we have achieved four of the specified pre-clinical 
milestones under this research and license agreement and have received an aggregate of €2.7 million in milestone payments. For 
products commercialized under the License Agreement, if any, the Company is eligible to receive a mid-single digit royalty on net 
sales. 
For a designated period, which may include limited time periods following termination of this agreement, in certain circumstances we 
are prohibited from researching, developing or commercializing bispecific antibodies against the undisclosed target combination that 
are the subject of this agreement. Ono also provides funding for our research and development activities under an agreed-upon plan. 

23
This research and license agreement will expire after all milestone payments have been received and all related patent rights have 
expired, unless terminated earlier. Ono has the right to terminate this agreement at any time for any reason, with or without cause. The 
licenses granted to Ono may convert to royalty-free, fully-paid, perpetual licenses if Ono terminates the agreement for uncured 
material breach.
Betta Pharmaceuticals Co. Ltd. 
On December 10, 2018, we entered into a collaboration and license agreement with Betta Pharmaceuticals Co. Ltd. (Betta) where we 
granted Betta an exclusive license to develop and commercialize MCLA-129 in China. We retain all rights outside of China. Under 
the terms of the agreement, Betta retained a contract manufacturing organization with experience in filing IND applications with U.S. 
authorities and clinical trial applications (CTAs) with European regulatory authorities in order to produce clinical trial materials for 
the Chinese market and the rest of the world. 
In addition to a non-refundable upfront payment, we and Betta will share equally the cost of the transfer of the manufacturing 
technology to a contract manufacturing organization. We are also eligible to receive an aggregate of $12.0 million in milestone 
payments contingent upon Betta achieving certain specified development and commercial goals as well as tiered royalty payments of 
net sales of any products resulting from the collaboration in China. Betta is eligible to receive milestone payments contingent upon us 
achieving certain specified development and commercial goals, and is eligible to receive tiered royalty payments of net sales outside 
of China. 
Gilead Sciences
On March 5, 2024, we entered into a collaboration, option and license agreement (Gilead Collaboration Agreement) and share 
subscription agreement Gilead Subscription Agreement) with Gilead Sciences, Inc. (Gilead). Under the terms of the Collaboration 
Agreement, we and Gilead agreed to collaborate on the use of Merus’ proprietary Triclonics® platform to develop certain trispecific 
T-cell engaging multi-specific antibody products for the treatment of certain indications. The collaboration shall include at least two, 
but may include up to three, separate preclinical research programs (each, a Program) for the design and validation of candidates 
directed to the applicable program targets selected by Gilead. On a Program-by-Program basis, we have granted Gilead an exclusive 
option to obtain an exclusive license for such Program. If Gilead exercises the license option with respect to a Program, Gilead will be 
responsible for the development and commercialization of the products arising from such Program. Gilead paid an upfront, non-
refundable payment of $56.0 million for the rights granted under the Gilead Collaboration Agreement. If Gilead exercises its option to 
an additional Program, we will receive an initiation fee of $28.0 million. If Gilead exercises its license option for all Programs, we will 
receive up to a total of approximately $1.5 billion across all three programs. We are further eligible to receive, with respect to all 
products arising from a Program, if approved, and country-by-country basis, tiered royalties based on the level of worldwide aggregate 
annual net sales at percentages ranging from the mid-single digits to low double digits until the royalty term expires, subject to 
customary reductions. For the third potential Program, we also have an option to forego unachieved development milestones and 
royalties to enter into a 50/50 split of net profits and net losses arrangement upon a specified time period triggered by the first 
investigational new drug application filing for the third Program. In connection with entering into the Gilead Collaboration 
Agreement, pursuant to the Subscription Agreement, Gilead purchased 452,527 common shares of the Company at a price per share of 
$55.2454 for aggregate gross proceeds to us of approximately $25.0 million. Gilead agreed not to transfer, sell, or otherwise dispose 
of the shares for a period of time following the purchase of the Shares, subject to certain customary exceptions.
Partner Therapeutics
On November 27, 2024, we entered into a License Agreement (the PTx License Agreement) with Partner Therapeutics, Inc., a 
Delaware corporation (PTx). Under the terms of the License Agreement, we granted PTx (i) an exclusive, sublicenseable, royalty-
bearing license under certain patent rights and know-how to (a) exploit zenocutuzumab for the treatment of NRG1+ cancer in the 
United States and (b) develop, manufacture and commercialize companion diagnostic tests with respect to zenocutuzumab for the 
treatment of NRG1+ cancer in the United States and (ii) a limited, non-exclusive, non-sublicenseable, royalty-bearing license under 
certain patent rights and know-how to commercialize zenocutuzumab for the treatment of NRG1+ cancer outside of the United States 
solely in connection with a named patient program for a limited time, until we file for any regulatory approval for zenocutuzumab in 
any country outside the United States. We retain all rights not granted to PTx. PTx granted to us an exclusive, fully paid, royalty-free, 
perpetual and irrevocable license, with the right to grant sublicenses, to certain intellectual property of PTx to exploit zenocutuzumab 
for (1) the treatment of NRG1+ cancer in a country outside of the United States and (2) for any other uses of zenocutuzumab outside 
the field of treatment of NRG1 fusion cancer worldwide. In exchange for the rights granted under the License Agreement, PTx agreed 
to pay an upfront, non-refundable payment, agreed to fund the development, manufacturing and clinical trial expenses for 
zenocutuzumab and certain companion diagnostic products (other than a portion of the expenses we have agreed to share, associated 
with securing or maintaining approval from the United States Food and Drug Administration) and we are eligible to receive up to 
$130.0 million in potential commercialization milestone payments based on annual net sales of zenocutuzumab. We are also eligible 
to receive tiered royalties based on the level of aggregate annual net sales ranging from high single digits to low twenties until the 
royalty term expires. If after three years after the launch of zenocutuzumab in the United States, PTx does not to achieve certain 
specified annual net sales targets, we and PTx will work in good faith to develop a plan to improve net sales. If in the subsequent year 

24
PTx does not achieve the specified annual net sales target, we have the right to terminate the License Agreement, with all rights 
reverting to us.
Manufacturing 
Our Biclonics® technology platform relies on third parties for manufacturing our product candidates. We rely on and expect to 
continue to rely on third-party contract manufacturing organizations (CMOs) for the supply of current good manufacturing practice-
grade (cGMP-grade) clinical trial materials and commercial quantities of our antibody candidates and products, if approved. We 
currently have a commercial production agreement for zenocutuzumab, which we are planning to transition to PTx. For our other 
product candidates, we have contracted several biopharmaceutical CMOs for the clinical manufacture of MCLA-158 or 
petosemtamab, and MCLA-129. We believe that the standardized Biclonics® manufacturing process can be transferred to additional 
CMOs and potential future co-development or co-commercialization collaborations or partnerships for the production of clinical and 
commercial supplies of our Biclonics® in the ordinary course of business. 
Sales and Marketing 
We have not yet defined our sales, marketing or product distribution strategy for petosemtamab, MCLA-129, or any of our other 
antibody candidates. In December 2024, Merus entered into an agreement with Partner Therapuetics (PTx) in which we exclusively 
licensed to PTx the right to commercialize zenocutuzumab (Zeno) for the treatment of NRG1+ cancer in the United States. Under the 
terms of the agreement, following a specified transition period, PTx will assume full rights to U.S. commercialization of Zeno for the 
treatment of NRG1+ cancer. Future commercial strategy may include the use of strategic partners, distributors, a contract sales force, 
or the establishment of our own commercial infrastructure. We plan to further evaluate these alternatives as we approach approval, if 
any, for one of our antibody candidates. 
Competition
We compete directly with companies that focus on oncology and companies dedicating their resources to cancer therapies. We also 
face competition from academic research institutions, governmental agencies and other various public and private research 
institutions. With the proliferation of new drugs and therapies into oncology, we expect to face increasingly intense competition as 
new technologies become available and new therapeutic candidates are clinically developed or approved therapies are explored for 
new indications. Any antibody candidates that we successfully develop and commercialize will compete with existing therapies and 
new therapies that may become available in the future. 
Many of our competitors have significantly greater financial, manufacturing, marketing, drug development, technical and human 
resources 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 top qualified scientific and management personnel and establishing clinical trial sites 
and patient registration for clinical trials, manufacturer’s production capacity, 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 antibody candidates, if approved, are likely to be their 
efficacy, safety, dosing convenience, price, the effectiveness of companion diagnostics in guiding the use of 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, less expensive, more convenient or easier to administer, or have fewer or less severe side effects 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. Even if our antibody candidates achieve marketing approval, they may be priced at a significant premium over competitive 
products if any have been approved by then.
In addition to currently marketed therapies, there are also a number of products in late-stage clinical development to treat cancer, 
including other bispecific antibodies or similar molecules. Our closest competitors in this area include Genmab A/S, Janssen 
Pharmaceutical Companies, Regeneron Pharmaceuticals, Inc., Bicara Therapeutics, Exelixis, Inc., Pfizer, Inc. and Xencor, Inc. The 
antibody candidates in development by competitors may provide efficacy, safety, dosing convenience and other benefits that are not 
provided by currently marketed therapies. As a result, they may provide significant competition for any of our antibody candidates for 
which we obtain marketing approval. 

25
Intellectual Property
We strive to protect and enhance the proprietary technologies, inventions, and improvements that we believe are important to our 
business, including seeking, maintaining, and defending patent rights, whether developed internally or licensed from third parties. Our 
policy is to seek to protect our proprietary position by, among other methods, pursuing and obtaining patent protection in the United 
States and in jurisdictions outside of the United States related to our proprietary technology, inventions, improvements, platforms and 
antibody candidates that are important to the development and implementation of our business. 
As of January 31, 2025: 
 
•
Our patent portfolio related to our bispecific antibody candidate zenocutuzumab comprises one application filed under the 
Patent Cooperation Treaty (PCT) application, filed on February 27, 2015 with two issued patents in Europe, one in the 
United States and 14 other foreign jurisdictions and applications pending in Europe, the United States and 8 other foreign 
jurisdictions with an expected expiry not earlier than February 2035. Claims are directed to the zenocutuzumab 
composition of matter and methods of using zenocutuzumab to treat subjects having or at risk of having a HER2 and/or 
HER3 positive tumor. In addition, our portfolio includes nine PCT patent applications directed to methods of using 
zenocutuzumab, including in combination therapies to treat patients, concerning methods of treating patients with cancer 
harboring NRG1 gene fusions, patients with certain forms of HER3 positive tumors. One of these PCT applications was 
filed on April 3, 2018, with issued claims in two foreign jurisdictions and applications pending in Europe, the United 
States and 16 other foreign jurisdictions, with an expiry date not earlier than April 2038. Claims are directed to methods of 
treatment using zenocutuzumab, including in combination with an HER2 targeting agent in patients with an HER2/HER3 
positive tumor, like a tumor in the breast or brain. The second of these PCT applications was filed on April 3, 2018, with 
applications pending in Europe, the United States and four other foreign jurisdictions, with an expiry date not earlier than 
April 2038. Claims are directed to methods of treatment using zenocutuzumab in patients having an HER2/HER3 positive 
tumor but not previously treated with a HER2 specific therapy or with a HER3 specific therapy. The third of these PCT 
applications was filed on April 3, 2018, with an issued patent in the United States, one foreign jurisdiction and 
applications pending in Europe, the United States and 17 other foreign jurisdictions, with an expiry date not earlier than 
April 2038. Claims are directed to methods of treating patients with cancers harboring NRG1 gene fusions. The fourth of 
these PCT applications was filed on May 17, 2018, with issued claims in Europe, the United States, and eight foreign 
jurisdictions and applications pending in the three other foreign jurisdictions, with an expiry date not earlier than May 
2038. Claims are directed to methods of treatment using zenocutuzumab, including in combination with endocrine therapy 
of patients with cancers, such as hormone receptor positive breast cancer. The fifth of these PCT applications was filed on 
October 23, 2020, with issued claims in one foreign jurisdiction, and applications pending in Europe, the United States 
and eight other foreign jurisdictions, with an expiry date not earlier than October 2040. Claims are directed to methods of 
treatment using zenocutuzumab in patients with NRG1-fusion positive cancers, including in patients that progressed after 
having received prior treatment certain treatment. The sixth of these PCT applications was filed on November 3, 2021, 
with applications pending in Europe, the United States and three other foreign jurisdictions, and an expiry date not earlier 
than November 2041. Claims are directed to treatment of patients with certain HER3 positive cancers using 
zenocutuzumab. The seventh of these PCT applications was filed on June 1st, 2022, with applications pending in Europe, 
the United States and three other foreign jurisdictions, and an expiry date not earlier than June 2042. Claims are directed 
to further identified NRG1 fusions, methods of detecting such and methods of treatment using zenocutuzumab. The eighth 
of these PCT applications was filed on June 1st, 2022, with applications pending in Europe, the United States and two 
other foreign jurisdictions, and an expiry date not later than June 2042. Claims are directed to detecting NRG1 fusions 
using liquid biopsy assays, and methods of treating identified patients using zenocutuzumab. The ninth of these PCT 
applications was filed on August 4th, 2023, with a PCT application pending and in one foreign jurisdiction, and an expiry 
date not earlier than August 2043. Claims are directed to treatment of patients with castration-resistant prostate cancer.
 
•
Our patent portfolio related to our CD3 technology comprises a first PCT application, filed on July 8, 2016, with issued 
patents in the United States, Europe and 11 foreign jurisdictions, and applications pending in the United States, Europe 
and seven foreign jurisdictions with an expected expiry not earlier than July 2036. A second PCT application was filed on 
March 27, 2020, with applications pending in the United States, Europe, and 20 foreign jurisdictions with an expected 
expiry not earlier than March 2040. Claims are related to the anti-CD3 binding domains, antibodies, their use, among 
other subject matter.
 
•
Our patent portfolio related to our bispecific antibody candidate petosemtamab comprises one PCT filed on October 21, 
2016, with one issued patent in Europe, one issued in the United States and 11 issued patents in foreign jurisdictions and 
applications pending in Europe, the United States and nine other foreign jurisdictions with an expiry not earlier than 
October 2036. Claims are directed to the petosemtamab composition of matter and methods of using petosemtamab in the 

26
treatment or prevention of various solid tumors. In addition, our portfolio includes seven PCT applications, one of which 
was filed on August 19, 2020, with issued claims in one foreign jurisdiction and with applications pending in Europe, the 
United States and 18 other foreign jurisdictions with an expiry no earlier than August 2040. Claims are directed to a 
combination treatment with a topoisomerase I inhibitor to treat patients. The second PCT application was filed on April 
23, 2021, with applications pending in Europe, the United States and 18 other foreign jurisdictions with an expiry no 
earlier than April 2041. Claims are directed to treatment of patients having gastric, esophageal and gastro-esophageal 
cancer including certain dosing regimens. The third PCT application was filed on December 15, 2021, with applications 
pending in Europe, the United States and 18 other foreign jurisdictions with an expiry no earlier than December 2041, 
directed to treatment of patients having head and neck cancer, including certain dosing regimens. The fourth PCT 
application was filed on December 16, 2021, with applications pending in Europe, the United States and 15 other foreign 
jurisdictions with an expiry no earlier than December 2041 directed to a pharmaceutical formulation that contains 
petosemtamab. The fifth PCT application was filed on October 6, 2022, with applications pending in Europe, the United 
States and 18 foreign jurisdictions, with an expiry not earlier than October 2042, with claims directed to the treatment of 
patients having a cancer with high EGFR expression levels. The sixth PCT application was filed on December 23, 2023, 
with national phase entry due in May 2025, with an expiry no earlier than December 2043, with claims directed to a 
combination treatment using petosemtamab and an immune checkpoint inhibitor in patients having a cancer, including 
head and neck cancer. The seventh PCT application was filed on December 28, 2023, with national phase entry due in 
May 2025, with an expiry no earlier than December 2043, with claims directed to a combination treatment using 
petosemtamab and a chemotherapeutic agent in patients having a cancer, including colorectal cancer.
 
•
Our patent portfolio related our bispecific antibody candidate MCLA-129 comprises one PCT filed on August 9, 2018, 
with one issued patent in Europe and one issued in the United States and in two foreign jurisdictions, with applications 
pending in the United States, Europe and 20 other foreign jurisdictions with an expiry of not earlier than August 2038. 
Claims are directed to the MCLA-129 composition of matter and methods of using MCLA-129 in the treatment or 
prevention of various solid tumors. In addition, our portfolio includes two PCT applications, one of which was filed on 
March 7, 2023, with applications pending in Europe, the United Stats and three foreign jurisdictions, with an expiry not 
earlier than March 2043, with claims directed to, among other things, the treatment of patients using a combination of 
MCLA-129 and a third generation EGFR tyrosine kinase inhibitor. The second PCT application was filed on March 7, 
2023, with applications pending in Europe, the United States and 17 foreign jurisdictions, with an expiry not earlier than 
March 2043, with claims directed to, among other things, treatment of previously treated patients having cancer using 
MCLA-129.
 
•
Our patent portfolio related to our bispecific antibody candidate MCLA-145 comprises one PCT filed on September 22, 
2017, with an issued patent in Europe and the United States and 11 issued patents in a foreign jurisdiction and with 
applications pending in the United States, Europe and 16 other foreign jurisdictions with an expiry not earlier than 
September 2037. Claims are directed to the MCLA-145 composition of matter and methods of using MCLA-145 in the 
treatment or prevention of various solid tumors. In addition, our portfolio includes two PCT applications, one of which 
was filed on December 3, 2021, with applications pending in the United States, Europe and 9 foreign jurisdictions, related 
to dosage regimens and methods of treating patients with certain kinds of solid tumors, with an expiry no earlier than 
December 2041. The second PCT application was filed on January 24, 2023,with applications pending in the United 
States, Europe and three foreign jurisdictions, with an expiry not earlier than January 2043, with claims directed to, among 
other things, treatment of patients having cancer using MCLA-145 and a PD-L1 or PD-1 inhibitor. 
 
•
Our patent portfolio related to our MeMo® and common light chain transgenic animal consists of nine issued U.S. 
patents, five pending U.S. applications, three issued European patents that have been validated in many countries, and one 
pending European application, 26 issued foreign patents and nine pending foreign applications, all with an expected 
expiry not earlier than June 2029. Claims are directed to a common light chain animal and methods of producing 
hybridomas, host cells, and antibodies relating to the use of a common light chain and by exposing the animal to an 
antigen.
 
•
Our patent portfolio related to efficient dimerization of heavy chains promoting efficient production of multispecific 
antibodies, binding domains and mixtures of antibodies, methods and host cells for recombinant production thereof, and 
comprises two PCT applications filed on April 19, 2013, which has resulted in nine issued U.S. patents, one pending U.S. 
applications, two issued European patents, two pending European applications, 38 issued foreign patents, and 21 pending 
foreign applications, all with an expected expiry not earlier than April 2033.
 

27
•
Our patent portfolio related to our trispecific antibody technology comprises one PCT application, filed on March 29, 
2019, with one issued patent in the United States and two issued foreign patents, and pending applications in the United 
States, Europe, and 20 foreign jurisdictions, with an expiry no earlier than March 2039. Claims are directed to, among 
other things, a multivalent antibody format, including the Triclonics® format.
•
Our patent portfolio related to our Spleen to Screen® technology consists of four issued U.S. patents, one pending U.S. 
application, one pending European application and four issued foreign patents, with one foreign pending application, all 
with an expected expiry not earlier than September 2032.
We plan to continue to expand our intellectual property estate by filing patent applications directed to dosage forms, methods of 
treatment and additional compositions created or identified from our ADClonics®, Biclonics® and Triclonics® technology platforms, 
improvements to those platforms and our ongoing development of our antibody candidates. Specifically, we seek patent protection in 
the United States and internationally for novel compositions of matter directed to aspects of the molecules, basic structures and 
processes for manufacturing these molecules and the use of these molecules in a variety of therapies, in combinations, dosages, 
methods of treatments, among other features.
Our patent portfolio is intended to cover, but is not limited to, the composition of matter of our bispecific antibody candidates, their 
methods of use, the ADClonics®,  Biclonics® and Triclonics® technology platforms used to generate them, related technologies 
and/or other aspects of the inventions that are important to our business, including our MeMo® mouse, and common light chain 
generation platforms and techniques, Spleen to Screen® technology, and recombinant host cells capable of producing our antibody 
candidates, methods of purification, and heterodimerization, among other proprietary technology. We also rely on trademarks, 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.
We also rely on know-how, continuing technological innovation and in-licensing opportunities to develop, strengthen, and maintain 
our proprietary positions.
Our success will depend 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 valid and enforceable 
patents and other proprietary rights of third parties. For important factors related to our proprietary technology, inventions, 
improvements, platforms and antibody candidates, please see the section entitled “Risk Factors—Risks Related to Intellectual 
Property and Information Technology.”
Government Regulation
We are subject to extensive regulation. We expect our antibody candidates to be regulated as biologics. Biological products are subject 
to regulation under the Federal Food, Drug, and Cosmetic Act (FD&C Act) and the Public Health Service Act (PHS Act) and other 
federal, state, local and foreign statutes and regulations. Both the FD&C Act and the PHS Act and their corresponding regulations 
govern, among other things, the testing, manufacturing, safety, efficacy, labeling, packaging, storage, record keeping, distribution, 
reporting, advertising and other promotional practices involving biological products.
U.S. Biological Products Development Process
The process required by the FDA before a biologic may be marketed in the United States generally involves the following:
•
completion of extensive nonclinical, sometimes referred to as pre-clinical, laboratory tests, and pre-clinical animal studies 
and applicable requirements for the humane use of laboratory animals and formulation studies in accordance with 
applicable regulations, including good laboratory practices (GLPs) for certain trials; 
•
submission to the FDA of an IND, which must become effective before human clinical trials may begin; 
•
approval by an institutional review board (IRB) or ethics committee at each clinical site before the trial is commenced;
•
performance of adequate and well-controlled human clinical trials according to the FDA’s regulations, commonly referred 
to as good clinical practice (GCP), regulations and any additional requirements for the protection of human research 
subjects and their health information, to establish the safety and efficacy of the proposed biological product for its intended 
use; 
•
submission to the FDA of a Biologics License Application (BLA) that includes substantive evidence of safety, purity, and 
potency from results of nonclinical testing and clinical trials; 

28
•
satisfactory completion of an FDA inspection of the manufacturing facility or facilities where the biological product is 
produced to assess compliance with current Good Manufacturing Practice (cGMP) requirements to assure that the facilities, 
methods and controls are adequate to preserve the biological product’s identity, strength, quality and purity; 
•
potential FDA audit of certain nonclinical and clinical trial sites that generated the data in support of the BLA; and 
•
FDA review and approval, or licensure, of the BLA.
Before testing any antibody candidate in humans, the antibody candidate enters the pre-clinical testing stage. Pre-clinical tests, also 
referred to as nonclinical trials or studies, generally include laboratory evaluations of product chemistry, toxicity and formulation, as 
well as animal studies to assess the potential safety and activity of the antibody candidate. The conduct of certain pre-clinical tests 
must comply with federal regulations and requirements including GLPs. 
The clinical trial sponsor must submit the results of the pre-clinical tests, together with manufacturing information, analytical data, any 
available clinical data or literature and a proposed clinical protocol, to the FDA as part of the IND. Some pre-clinical testing may 
continue even after the IND is submitted. The IND automatically becomes effective 30 days after receipt by the FDA, unless the FDA 
places the clinical trial on a clinical hold within that 30-day time period. In such a case, the IND sponsor and the FDA must resolve 
any outstanding concerns before the clinical trial can begin. The FDA may also impose clinical holds, at any time before or during 
clinical trials due to safety concerns or non-compliance. If the FDA imposes a clinical hold, trials may not recommence without FDA 
authorization and then only under terms authorized by the FDA. 
Clinical trials involve the administration of the biological antibody candidate to healthy volunteers or patients under the supervision of 
qualified investigators, generally physicians not employed by or under the trial sponsor’s control. Clinical trials are conducted under 
protocols detailing, among other things, the objectives of the clinical trial, dosing procedures, subject selection and exclusion criteria, 
and the parameters to be used to monitor subject safety, including stopping rules that assure a clinical trial will be stopped if certain 
adverse events should occur. Each protocol and any amendments to the protocol must be submitted to the FDA as part of the IND. 
While the IND is active, progress reports summarizing the results of the clinical trials and nonclinical studies performed since the last 
progress report, among other information, must be submitted at least annually to the FDA, and written IND safety reports must be 
submitted to the FDA and investigators for serious and unexpected suspected adverse events, findings from other studies suggesting a 
significant risk to humans exposed to the same or similar drugs, findings from animal or in vitro testing suggesting a significant risk to 
humans, and any clinically important increased incidence of a serious suspected adverse reaction compared to that listed in the 
protocol or investigator brochure. 
Clinical trials must be conducted and monitored in accordance with the FDA’s regulations comprising the GCP requirements, 
including, among other things, the requirement that all research subjects provide informed consent. Further, each clinical trial must be 
reviewed and approved by an independent IRB at or servicing each institution at which the clinical trial will be conducted. An IRB is 
charged with protecting the welfare and rights of trial participants and considers such items as whether the risks to individuals 
participating in the clinical trials are minimized and are reasonable in relation to anticipated benefits. The IRB also approves the form 
and content of the informed consent that must be signed by each clinical trial subject or his or her legal representative and must 
monitor the clinical trial until completed. There are also requirements governing the reporting of ongoing clinical trials and completed 
clinical trial results to public registries.
Human clinical trials are typically conducted in three sequential phases that may overlap or be combined: 
•
Phase 1. The biological antibody candidate is initially introduced into healthy human subjects and tested for safety. In the 
case of some products for severe or life-threatening diseases, especially when the product may be too inherently toxic to 
ethically administer to healthy volunteers, the initial human testing is often conducted in patients. 
•
Phase 2. The biological antibody candidate is evaluated in 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, optimal dosage and dosing schedule. 
•
Phase 3. The biological antibody candidate is further evaluated for dosage, clinical efficacy, potency, and safety in an 
expanded patient population at geographically dispersed clinical trial sites. These clinical trials are intended to establish the 
overall risk/benefit ratio of the product and provide an adequate basis for product labeling. 
In some cases, the FDA may require, or sponsors may voluntarily pursue, additional clinical trials after a product is approved to gain 
more information about the product. In addition, the FDA may require post marketing clinical trials, sometimes referred to as phase 4 
clinical trials, designed to further assess a biological product’s safety and effectiveness, and testing and surveillance programs to 
monitor the safety of approved products that have been commercialized. These so-called phase 4 studies may also be made a condition 
to approval of the BLA.

29
Concurrent with clinical trials, companies usually complete additional animal trials and must also develop additional information 
about the physical characteristics of the biological antibody candidate as well as finalize a process for manufacturing the product in 
commercial quantities in accordance with cGMP requirements. To help reduce the risk of the introduction of adventitious agents with 
use of biological products, the PHS Act emphasizes the importance of manufacturing control for products whose attributes cannot be 
precisely defined. The manufacturing process must be capable of consistently producing quality batches of the biological antibody 
candidate and, among other things, the sponsor must develop methods for testing the identity, strength, quality, potency and purity of 
the final biological product. Additionally, appropriate packaging must be selected and tested and stability studies must be conducted to 
demonstrate that the biological antibody candidate does not undergo unacceptable deterioration over its shelf life. 
U.S. Review and Approval Processes 
After the completion of clinical trials of a biological antibody candidate, FDA approval of a BLA must be obtained before commercial 
marketing of the biological product. The BLA must include results of product development, laboratory and animal trials, human trials, 
information on the manufacture and composition of the product, proposed labeling and other relevant information. In addition, under 
the Pediatric Research Equity Act (PREA) a BLA or supplement to a BLA must contain data to assess the safety and effectiveness of 
the biological antibody candidate 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. 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 must submit an initial Pediatric Study Plan within sixty days after an end-of-phase 2 
meeting or as may be agreed between the sponsor and FDA. Unless otherwise required by regulation, PREA does not apply to any 
biological product for an indication for which orphan designation has been granted. 
Under the Prescription Drug User Fee Act (PDUFA), as amended, each BLA must be accompanied by a user fee. The FDA adjusts the 
PDUFA user fees on an annual basis. Fee waivers or reductions are available in certain circumstances, including a waiver of the 
application fee for the first application filed by a small business. Additionally, no user fees are assessed on BLAs for products 
designated as orphan drugs, unless the product also includes a non-orphan indication. 
Within 60 days following submission of the application, the FDA reviews a BLA submitted to determine if it is substantially complete 
before the agency accepts it for filing. The FDA may refuse to file any BLA that it deems incomplete or not properly reviewable at the 
time of submission and may request additional information. In this event, the BLA must be resubmitted with the additional 
information. The resubmitted application also is subject to review before the FDA accepts it for filing. Once the submission is 
accepted for filing, the FDA begins an in-depth substantive review of the BLA. The FDA’s goal is to review standard applications for 
original BLAs within ten months after the filing date, or, if the application qualifies for priority review, six months after the FDA 
accepts the application for filing. In both standard and priority reviews, the review process may also be extended by FDA requests for 
additional information or clarification.
The FDA reviews the BLA to determine, among other things, whether the proposed product is safe, pure and potent, and whether the 
product is being manufactured in accordance with cGMP requirements to assure and preserve the product’s identity, safety, strength, 
quality, potency and purity. The FDA may refer applications for novel biological products or biological products that present difficult 
questions of safety or efficacy to an advisory committee, typically a panel that includes clinicians and other experts, for review, 
evaluation and a recommendation as to whether the application should be approved and under what conditions. The FDA is not bound 
by the recommendations of an advisory committee, but it considers such recommendations carefully when making decisions. During 
the biological product approval process, the FDA also will determine whether a Risk Evaluation and Mitigation Strategy (REMS) is 
necessary to assure the safe use of the biological antibody candidate. If the FDA concludes a REMS is needed, the sponsor of the BLA 
must submit a proposed REMS; the FDA will not approve the BLA without a REMS, if required.
Before approving a BLA, the FDA will inspect the facilities at which the product is manufactured. The FDA will not approve the 
product unless it determines that the manufacturing processes and facilities are in compliance with cGMP requirements and adequate 
to assure consistent production of the product within required specifications. Additionally, before approving a BLA, the FDA will 
typically inspect one or more clinical sites to assure that the clinical trials were conducted in compliance with IND trial requirements 
and GCP requirements. 
Notwithstanding the submission of relevant data and information, the FDA may ultimately decide that the BLA does not satisfy its 
regulatory criteria for approval and deny approval. If the FDA decides not to approve the BLA in its present form, the FDA will issue 
a complete response letter that usually describes all of the specific deficiencies in the BLA identified by the FDA. The deficiencies 
identified may be minor, for example, requiring labeling changes, or major, for example, requiring additional clinical trials. 
Additionally, the complete response letter may include recommended actions that the applicant might take to place the application in a 
condition for approval. If a complete response letter is issued, the applicant may either resubmit the BLA, addressing all of the 
deficiencies identified in the letter, or withdraw the application. 

30
If a product receives regulatory approval, the approval may be significantly limited to specific diseases and dosages or the indications 
for use may otherwise be limited, which could restrict the commercial value of the product. Further, the FDA may require that certain 
contraindications, warnings or precautions be included in the product labeling. The FDA may impose restrictions and conditions on 
product distribution, prescribing, or dispensing in the form of a REMS, or otherwise limit the scope of any approval. In addition, the 
FDA may require post marketing clinical trials, sometimes referred to as phase 4 clinical trials, designed to further assess a biological 
product’s safety and effectiveness, and testing and surveillance programs to monitor the safety of approved products that have been 
commercialized. 
Orphan Drug Designation 
The FDA may grant orphan drug designation (or orphan designation) to drugs intended to treat a rare disease or condition that affects 
fewer than 200,000 individuals in the United States, or if it affects more than 200,000 individuals in the United States, there is no 
reasonable expectation that the cost of developing and marketing the drug for this type of disease or condition will be recovered from 
sales in the United States. Orphan designation must be requested before submitting a BLA. After the FDA grants orphan designation, 
the identity of the therapeutic agent and its potential orphan use are disclosed publicly by the FDA. Orphan designation does not 
convey any advantage in or shorten the duration of the regulatory review and approval process. 
In the United States, orphan drug designation entitles a party to financial incentives such as opportunities for grant funding towards 
clinical trial costs, tax advantages and user-fee waivers. In addition, if a product receives the first FDA approval for the disease or 
condition for which it has orphan designation, the product is entitled to orphan drug exclusivity, which means the FDA may not 
approve any other application to market the same drug for the same disease or condition for a period of seven years, except in limited 
circumstances, such as a showing of clinical superiority over the product with orphan exclusivity or where the manufacturer with 
orphan exclusivity is unable to assure sufficient quantities of the approved orphan designated product. Competitors, however, may 
receive approval of different products for the disease or condition for which the orphan drug or product has exclusivity or obtain 
approval for the same product but for a different disease or condition for which the orphan drug or product has exclusivity. If a drug or 
biological product has an orphan designation it receives marketing approval for a disease or condition broader than what is designated, 
it may not be entitled to orphan exclusivity. 
Expedited Development and Review Programs 
The FDA offers a number of expedited development and review programs for qualifying product candidates. For example, the FDA 
has a Fast Track program that is intended to expedite or facilitate the process for reviewing investigational biological products that 
meet certain criteria. Specifically, biological product candidates are eligible for Fast Track designation if they are intended to treat a 
serious or life-threatening disease or condition and demonstrate the potential to address unmet medical needs for such diseases or 
conditions. Fast Track designation applies to the combination of the product and the specific indication for which it is being studied. 
The sponsor of a Fast Track product candidate has opportunities for more frequent interactions with the applicable FDA review team 
during product development and, once a BLA is submitted, the application may be eligible for priority review. With regard to a Fast 
Track product, the FDA may consider for review sections of the marketing application on a rolling basis before the complete 
application is submitted, if the sponsor provides a schedule for the submission of the sections of the application, the FDA agrees to 
accept sections of the application and determines that the schedule is acceptable, and the sponsor pays any required user fees upon 
submission of the first section of the application. 
A product candidate intended to treat a serious or life-threatening disease or condition may also be eligible for Breakthrough Therapy 
designation to expedite its development and review. The criteria for Breakthrough Therapy designation require preliminary clinical 
evidence that demonstrates the drug may have substantial improvement on at least one clinically significant endpoint over available 
therapy. The designation includes all of the Fast Track program features, as well as more intensive FDA interaction and guidance 
beginning as early as phase 1 and an organizational commitment to expedite the development and review of the product candidate, 
including involvement of senior managers.
Any marketing application for a biologic product candidate submitted to the FDA for approval, including a product candidate with a 
Fast Track designation and/or Breakthrough Therapy designation, may be eligible for other types of FDA programs intended to 
expedite the FDA review and approval process. For example, a BLA is eligible for priority review if a product candidate is intended to 
treat a serious disease or condition, if approved, would provide a significant improvement in safety or effectiveness compared to 
marketed products. The FDA will attempt to direct additional resources to the evaluation of an application for a new biological 
product designated for priority review in an effort to facilitate the review. Additionally, depending on the design of the applicable 
clinical trials, a product candidate may be eligible for accelerated approval. Biological products studied for their safety and 
effectiveness in treating serious or life-threatening illnesses and that provide meaningful advantages over existing treatments may be 
eligible for accelerated approval, which means that they may be approved on the basis of adequate and well-controlled clinical trials 
supporting a determination that the product has an effect on a surrogate endpoint or an intermediate clinical endpoint that is reasonably 
likely to predict a clinical benefit, or on the basis of an effect on a clinical endpoint other than survival or irreversible morbidity or 

31
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 approval, the FDA generally requires that a sponsor of a biological product subject to 
accelerated approval perform adequate and well-controlled confirmatory clinical trials to verify and describe the anticipated clinical 
benefit, and may require that such confirmatory trials be underway prior to granting accelerated approval. Biological products 
receiving accelerated approval may be subject to expedited withdrawal procedures if the sponsor fails to conduct the required 
confirmatory clinical trials in a timely manner or if such trials fail to verify the predicted clinical benefit. In addition, the FDA 
currently requires as a condition for accelerated approval pre-approval of promotional materials, which could adversely impact the 
timing of the commercial launch of the product.  
Fast Track designation, priority review and Breakthrough Therapy designation do not change the standards for approval but may 
expedite the development or approval process. Even if we receive one of these designations for our antibody candidates, the FDA may 
later decide that our antibody candidates no longer meet the conditions for qualification. In addition, these designations may not 
provide us with a material commercial advantage. 
Post-Approval Requirements 
Maintaining substantial compliance with applicable federal, state, and local statutes and regulations requires the expenditure of 
substantial time and financial resources. Rigorous and extensive FDA regulation of biological products continues after approval, 
particularly with respect to cGMP requirements. Manufacturers of approved biologics are required to comply with applicable 
requirements in the cGMP regulations, including quality control and quality assurance and maintenance of records and documentation. 
Other post-approval requirements applicable to biological products include record-keeping requirements, reporting of adverse effects, 
and reporting updated safety and efficacy information. 
Biological product manufacturers and other entities involved in the manufacture and distribution of approved biological products are 
required to register their establishments with the FDA and certain state agencies, and are subject to periodic unannounced inspections 
by the FDA and certain state agencies for compliance with cGMP requirements and other laws. Accordingly, manufacturers must 
continue to expend time, money, and effort in the area of production and quality control to maintain cGMP compliance. In addition, 
changes to the manufacturing process or facility generally require prior FDA approval before being implemented and other types of 
changes to the approved product, such as adding new indications and additional labeling claims, are also subject to further FDA 
review and approval. 
The FDA may withdraw 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 
revisions to the approved labeling to add new safety information; imposition of post-market studies or clinical studies to assess new 
safety risks; or imposition of distribution restrictions 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 untitled letters;
•
clinical holds on clinical studies;
•
refusal of the FDA to approve pending applications or supplements to approved applications, or suspension or revocation of 
product approvals;
•
product seizure or detention, or refusal to permit the import or export of products;
•
consent decrees, corporate integrity agreements, debarment or exclusion from federal healthcare programs;
•
mandated modification of promotional materials and labeling and the issuance of corrective information;
•
the issuance of safety alerts, Dear Healthcare Provider letters, press releases and other communications containing warnings 
or other safety information about the product; or
•
injunctions or the imposition of civil or criminal penalties.
The FDA closely regulates the marketing, labeling, advertising and promotion of biologics. A company can make only those claims 
that are 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. Failure to comply with these requirements can result in, among other things, adverse 
publicity, warning letters, corrective advertising and potential civil and criminal penalties. Physicians may prescribe legally available 
products for uses that are not described in the product’s labeling and that differ from those tested and approved by the FDA. Such off-
label uses are common across medical specialties. Physicians may believe that such off-label uses are the best treatment for many 
patients in varied circumstances. The FDA does not regulate the behavior of physicians in their choice of treatments. The FDA does, 
however, restrict a manufacturer’s communications on the subject of off-label use of their products.

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Biosimilars and Exclusivity 
The Biologics Price Competition and Innovation Act of 2009 (BPCIA) created an abbreviated approval pathway for biological 
products that are biosimilar to or interchangeable with an FDA-licensed reference biological product. 
Biosimilarity, which requires that there be no clinically meaningful differences between the biological product and the reference 
product in terms of safety, purity, and potency, can be shown through analytical studies, animal studies, and a clinical trial or studies. 
Interchangeability requires that a product is biosimilar to the reference product and the product must demonstrate that it can be 
expected to produce the same clinical results as the reference product in any given patient and, for products that are administered 
multiple times to an individual, the biologic and the reference biologic may be alternated or switched after one has been previously 
administered without increasing safety risks or risks of diminished efficacy relative to exclusive use of the reference biologic. 
Under the BPCIA, an application for a biosimilar product may not be submitted to the FDA until four years following the date that the 
reference product was first licensed by the FDA. In addition, the approval of a biosimilar product may not be made effective by the 
FDA until 12 years from the date on which the reference product was first licensed. During this 12-year period of exclusivity, another 
company may still market a competing version of the reference product if the FDA approves a full BLA for the competing product 
containing the sponsor’s own pre-clinical data and data from adequate and well-controlled clinical trials to demonstrate the safety, 
purity and potency of their product. The BPCIA also created certain exclusivity periods for biosimilars approved as interchangeable 
products.  
A biological product can also obtain pediatric market exclusivity in the United States. Pediatric exclusivity, if granted, adds six 
months to existing exclusivity periods and patent terms. This six-month exclusivity, which runs from the end of other exclusivity 
protection or patent term, may be granted based on the voluntary completion of a pediatric trial in accordance with an FDA-issued 
“Written Request” for such a trial. The issuance of a written request does not obligate the sponsor to complete the requested trials.
FDA Regulation of Companion Diagnostics
We expect that our antibody candidates may require use of an in vitro diagnostic to identify appropriate patient populations for our 
products. These diagnostics, often referred to as companion diagnostics, are regulated as medical devices. In the United States, the 
United States Federal Food, Drug and Cosmetics Act (FD&C Act) and its implementing regulations, and other federal and state 
statutes and regulations govern, among other things, medical device design and development, pre-clinical and clinical testing, 
premarket clearance or approval, registration and listing, manufacturing, labeling, storage, advertising and promotion, sales and 
distribution, export and import, and post-market surveillance. Unless an exemption applies, diagnostic tests require marketing 
clearance or approval from the FDA prior to commercial distribution. The two primary types of FDA marketing authorization 
applicable to a medical device are premarket notification, also called 510(k) clearance, and premarket approval (PMA) approval. We 
expect that any companion diagnostic developed for use with our antibody candidates may utilize the PMA pathway.
If use of a companion diagnostic is essential to safe and effective use of a drug or biologic product, then the FDA generally will 
require approval or clearance of the diagnostic contemporaneously with the approval of the therapeutic product. On August 6, 2014, 
the FDA issued a final guidance document addressing the development and approval process for “In Vitro Companion Diagnostic 
Devices.” According to the guidance, for novel candidates such as our antibody candidates, a companion diagnostic device and its 
corresponding drug or biologic candidate may be required to be approved or cleared contemporaneously by the FDA for the use 
indicated in the therapeutic product labeling, although the FDA may decide that it is appropriate to approve a therapeutic product even 
though a companion diagnostic device is not approved or cleared contemporaneously. In general, the FDA expects that a companion 
diagnostic that is intended for use with the therapeutic product will be later approved or cleared through an appropriate submission and 
the therapeutic product labeling will be revised to stipulate the use of the companion diagnostic. The guidance also explains that a 
companion diagnostic device used to make treatment decisions in clinical trials of a drug generally will be considered an 
investigational device, unless it is employed for an intended use for which the device is already approved or cleared. If used to make 
critical treatment decisions, such as patient selection, the diagnostic device generally will be considered a significant risk device under 
the FDA’s Investigational Device Exemption (IDE) regulations. Thus, the sponsor of the diagnostic device will be required to comply 
with the IDE regulations. According to the guidance, if a diagnostic device and a drug are to be studied together to support their 
respective approvals, both products can be studied in the same investigational study, if the study meets both the requirements of the 
IDE regulations and the IND regulations. The guidance provides that depending on the details of the study plan and subjects, a 
sponsor may seek to submit an IND alone, or both an IND and an IDE.  
The FDA generally requires companion diagnostics intended to select the patients who will respond to cancer treatment to obtain 
approval of a PMA for that diagnostic contemporaneously with approval of the therapeutic. The review of these in vitro companion 
diagnostics in conjunction with the review of a cancer therapeutic involves coordination of review by the FDA’s Center for Biologics 
Evaluation and Research and by the FDA’s Center for Devices and Radiological Health. The PMA process, including the gathering of 
clinical and pre-clinical data and the submission to and review by the FDA, can take several years or longer. It 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 

33
labeling. PMA applications are subject to an application fee. In addition, PMAs for certain devices must generally include the results 
from extensive pre-clinical and adequate and well-controlled clinical trials to establish the safety and effectiveness of the device for 
each indication for which FDA approval is sought. In particular, for a diagnostic, the applicant must demonstrate that the diagnostic 
produces reproducible results when the same sample is tested multiple times by multiple users at multiple laboratories. As part of the 
PMA review, the FDA will typically inspect the manufacturer’s facilities for compliance with the Quality System Regulation (QSR) 
which imposes elaborate testing, control, documentation and other quality assurance requirements. 
If the FDA evaluations of both the PMA application and the manufacturing facilities are favorable, the FDA will either issue an 
approval letter or an approvable letter, which usually contains a number of conditions that must be met in order to secure the final 
approval of the PMA, such as changes in labeling, or specific additional information, such as submission of final labeling, in order to 
secure final approval of the PMA. If the FDA concludes that the applicable criteria have been met, the FDA will issue a PMA for the 
approved indications, which can be more limited than those originally sought by the applicant. The PMA can include post-approval 
conditions that the FDA believes necessary to ensure the safety and effectiveness of the device, including, among other things, 
restrictions on labeling, promotion, sale and distribution.
If the FDA’s evaluation of the PMA or manufacturing facilities is not favorable, the FDA will deny approval of the PMA or issue a 
not approvable letter. A not approvable letter will outline the deficiencies in the application and, where practical, will identify what is 
necessary to make the PMA approvable. The FDA may also determine that additional clinical trials are necessary, in which case the 
PMA approval may be delayed for several months or years while the trials are conducted and then the data is submitted in an 
amendment to the PMA. Once granted, PMA approval may be withdrawn by the FDA if compliance with post approval requirements, 
conditions of approval or other regulatory standards is not maintained or problems are identified following initial marketing. PMA 
approval is not guaranteed, and the FDA may ultimately respond to a PMA submission with a not approvable determination based on 
deficiencies in the application and require additional clinical trials or other data that may be expensive and time-consuming to 
generate and that can substantially delay approval. 
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 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 United States.
Government Regulation Outside of the United States 
In addition to regulations in the United States, we are subject to a variety of regulations in other jurisdictions governing, among other 
things, clinical trials and any commercial sales and distribution of our products. Because biologically sourced raw materials are 
subject to unique contamination risks, their use may be restricted in some countries. In addition, ethical, social and legal concerns 
about gene-editing technology, gene therapy, genetic testing and genetic research could result in additional regulations restricting or 
prohibiting the processes we may use.
Whether or not we obtain FDA approval for a product, we must obtain the requisite approvals from regulatory authorities in foreign 
countries prior to the commencement of clinical trials or marketing of the product in those countries. The requirements and process 
governing the conduct of clinical trials, product licensing, pricing and reimbursement vary from country to country. If we fail to 
comply with applicable foreign regulatory requirements, we may be subject to, among other things, fines, suspension or withdrawal of 
regulatory approvals, product recalls, seizure of products, operating restrictions and criminal prosecution. 
Non-Clinical Studies and Clinical Trials
Similarly to the U.S., the various phases of non-clinical and clinical research in the European Union (EU) are subject to significant 
regulatory controls.
Non-clinical (pharmaco-toxicological) studies are performed to demonstrate the health or environmental safety of new chemical or 
biological substances. Non-clinical studies must be conducted in compliance with the principles of good laboratory practice, or GLP, 
as set forth in EU Directive 2004/10/EC (unless otherwise justified for certain particular medicinal products, e.g., radio-
pharmaceutical precursors for radio-labeling purposes). In particular, non-clinical studies, both in vitro and in vivo, must be planned, 
performed, monitored, recorded, reported and archived in accordance with the GLP principles, which define a set of rules and criteria 
for a quality system for the organizational process and the conditions for non-clinical studies. These GLP standards reflect the 
Organization for Economic Co-operation and Development requirements.

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Clinical trials of medicinal products in the EU must be conducted in accordance with EU and national regulations and the International 
Council for on Harmonization of Technical Requirements for Pharmaceuticals for Human Use (ICH), guidelines on Good Clinical 
Practices (GCP) as well as the applicable regulatory requirements and the ethical principles that have their origin in the Declaration of 
Helsinki.
The regulatory landscape related to clinical trials in the EU has been subject to recent changes. The EU Clinical Trials Regulation 
(CTR) which was adopted in April 2014 and repeals the EU Clinical Trials Directive, became applicable on January 31, 2022. Unlike 
directives, the CTR is directly applicable in all EU member states without the need for member states to further implement it into 
national law. The CTR notably harmonizes the assessment and supervision processes for clinical trials throughout the EU via a 
Clinical Trials Information System, which contains a centralized EU portal and database. 
While the EU Clinical Trials Directive required a separate clinical trial application (CTA) to be submitted in each member state in 
which the clinical trial takes place, to both the competent national health authority and an independent ethics committee, much like the 
FDA and IRB respectively, the CTR introduces a centralized process and only requires the submission of a single application to all 
member states concerned. The CTR allows sponsors to make a single submission to both the competent authority and an ethics 
committee in each member state, leading to a single decision per member state. The CTA must include, among other things, a copy of 
the trial protocol and an investigational medicinal product dossier containing information about the manufacture and quality of the 
medicinal product under investigation. The assessment procedure of the CTA has been harmonized as well, including a joint 
assessment by all member states concerned, and a separate assessment by each member state with respect to specific requirements 
related to its own territory, including ethics rules. Each member state’s decision is communicated to the sponsor via the centralized EU 
portal. Once the CTA is approved, clinical study development may proceed. 
The CTR transition period ended on January 31, 2025, and all clinical trials (and related applications) are now fully subject to the 
provisions of the CTR.
Medicines used in clinical trials must be manufactured in accordance with Good Manufacturing Practices (GMP). Other national and 
European Union-wide regulatory requirements may also apply.
During the development of a medicinal product, the European Medicines Agency (EMA) and national regulators provide the 
opportunity for dialogue and guidance on the development program. At the EMA level, this is usually done in the form of scientific 
advice, which is given by the Scientific Advice Working Party of the Committee for Medicinal Products for Human Use (CHMP). A 
fee is incurred with each scientific advice procedure. Advice from the EMA is typically provided based on questions concerning, for 
example, quality (chemistry, manufacturing and controls testing), nonclinical testing and clinical trials, and pharmacovigilance plans 
and risk-management programs.  Advice is not legally binding with regard to any future marketing authorization application of the 
product concerned.
Marketing Authorizations
In the EU, medicinal products can only be placed on the market after obtaining a marketing authorization (MA). To obtain regulatory 
approval of an investigational biological product in the EEA, we must submit a marketing authorization application (MAA). The 
process for doing this depends, among other things, on the nature of the medicinal product.
The centralized procedure results in a single MA, issued by the European Commission, based on the opinion of the Committee for 
Medicinal Products for Human Use, or CHMP, of the EMA which is valid across the entire territory of the EU. The centralized 
procedure is compulsory for certain human drugs that are: (i) derived from biotechnology processes, such as genetic engineering, (ii) 
contain a new active substance indicated for the treatment of certain diseases, such as HIV/AIDS, cancer, diabetes, neurodegenerative 
diseases, autoimmune and other immune dysfunctions and viral diseases, (iii) designated orphan medicines and (iv) advanced-therapy 
medicinal products, such as gene therapy, somatic cell therapy or tissue-engineered medicines. The centralized procedure may at the 
request of the applicant also be used in certain other cases and in particular for any other products containing new active substances 
not authorized in the EU or for product candidates which constitute a significant therapeutic, scientific, or technical innovation or for 
which the granting of authorization would be in the interests of public health in the EU. 
Under the centralized procedure, the maximum timeframe for the evaluation of a MAA by the EMA is 210 days.  This excludes so-
called clock stops, during which additional written or oral information is to be provided by the applicant in response to questions 
asked by the CHMP. At the end of the review period, the CHMP provides an opinion to the European Commission. If this opinion is 
favorable, the Commission may then adopt a decision to grant an MA.  
MAs have an initial duration of five years. After these five years, the authorization may be renewed on the basis of a reevaluation of 
the risk-benefit balance. Once renewed, the MA is valid for an unlimited period unless the European Commission or the competent 
authority of the EU member states decides, on justified grounds relating to pharmacovigilance, to proceed with one additional five-
year renewal.
Under the centralized procedure and in exceptional cases, the CHMP might perform an accelerated review of an MAA in no more than 
150 days (not including clock stops). Innovative products that target an unmet medical need and are expected to be of major public 

35
health interest may be eligible for a number of expedited development and review programs, such as the PRIME scheme, which 
provides incentives similar to the breakthrough therapy designation in the U.S. PRIME is a voluntary scheme aimed at enhancing the 
EMA’s support for the development of medicines that target unmet medical needs. It is based on increased interaction and early 
dialogue with companies developing promising medicines, to optimize their product development plans and speed up their evaluation 
to help them reach patients earlier. Product developers that benefit from PRIME designation can expect to be eligible for accelerated 
assessment but this is however not guaranteed. The benefits of a PRIME designation includes the appointment of a rapporteur from 
the CHMP before submission of an MAA, early dialogue and scientific advice at key development milestones, and the potential to 
qualify products for accelerated review earlier in the application process.
Data and Marketing Exclusivity
The EU also provides opportunities for market exclusivity. For example, in the EU, upon receiving MA, reference medicinal products 
generally receive eight years of data exclusivity and an additional two years of market exclusivity. If granted, data exclusivity period 
prevents generic or biosimilar applicants from relying on the pre-clinical and clinical trial data contained in the dossier of the reference 
product when applying for a generic or biosimilar MA in the EU during a period of eight years from the date on which the reference 
product was first authorized in the EU. The market exclusivity period prevents a successful generic or biosimilar applicant from 
commercializing its product in the EU until 10 years have elapsed from the initial MA of the reference product in the EU. The overall 
ten-year market exclusivity period may be extended to a maximum of eleven years if, during the first eight years a new therapeutic 
indication with significant clinical benefit over existing therapies is approved. However, there is no guarantee that a product will be 
considered by the EU’s regulatory authorities to be a new chemical entity, and products may not qualify for data exclusivity. 
There is a special regime for biosimilars, or biological medicinal products that are similar to a reference medicinal product but that do 
not meet the definition of a generic medicinal product, for example, because of differences in raw materials or manufacturing 
processes. For such products, the results of appropriate preclinical or clinical trials must be provided, and guidelines from the EMA 
detail the type of quantity of supplementary data to be provided for different types of biological product. There are no such guidelines 
for complex biological products, such as gene or cell therapy medicinal products, and so it is unlikely that biosimilars of those 
products will currently be approved in the EU. However, guidance from the EMA states that they will be considered in the future in 
light of the scientific knowledge and regulatory experience gained at the time. 
Orphan Medicinal Products
The criteria for designating an “orphan medicinal product” in the EU are similar in principle to those in the United States. A medicinal 
product may be designated as orphan if its sponsor can establish that: (1) it is intended for the diagnosis, prevention or treatment of a 
life-threatening or chronically debilitating condition; (2) either (a) such condition affects no more than five in 10,000 persons in the 
EU when the application is made, or (b) the product, without the benefits derived from orphan status, would not generate sufficient 
return in the EU to justify investment; and (3) there exists no satisfactory method of diagnosis, prevention or treatment of such 
condition authorized for marketing in the EU, or if such a method exists, the product will be of significant benefit to those affected by 
the condition. Orphan medicinal products are eligible for financial incentives such as reduction of fees or fee waivers, protocol 
assistance, and access to the centralized procedure. Upon grant of a MA, orphan medicinal products are entitled to a ten-year period of 
market exclusivity for the approved therapeutic indication, which means that during this period, the regulatory authorities cannot 
accept another application for a MA, or grant a MA or accept an application to extend an existing MA for the same indication, in 
respect of a similar medicinal product for a period of ten years. The period of market exclusivity is extended by two years for orphan 
medicinal products that have also complied with an agreed pediatric investigation plan. No extension to any supplementary protection 
certificate can be granted on the basis of pediatric studies for orphan indications. The application for orphan designation must be 
submitted before the MAA. The applicant will receive a fee reduction for the MAA if the orphan designation has been granted, but not 
if the designation is still pending at the time the MA is submitted. Orphan designation does not convey any advantage in, or shorten 
the duration of, the regulatory review and approval process. 
The 10-year market exclusivity may be reduced to six years if, at the end of the fifth year, it is established that the product no longer 
meets the criteria for orphan designation, for example, if the product is sufficiently profitable not to justify maintenance of market 
exclusivity or where the prevalence of the condition has increased above the threshold. Additionally, MA may be granted to a similar 
product for the same indication at any time if: 
•
the second applicant can establish that its product, although similar, is safer, more effective or otherwise clinically superior; 
•
the applicant consents to a second orphan medicinal product application; or 
•
the applicant cannot supply enough orphan medicinal product. 
Post-Approval Requirements
Similar to the United States, both MA holders and manufacturers of medicinal products are subject to comprehensive regulatory 
oversight by the EMA, the European Commission and/or the competent regulatory authorities of the member states. The holder of a 

36
MA must establish and maintain a pharmacovigilance system and appoint an individual qualified person for pharmacovigilance 
(QPPV) who is responsible for the establishment and maintenance of that system, and oversees the safety profiles of medicinal 
products and any emerging safety concerns. Key obligations include expedited reporting of suspected serious adverse reactions and 
submission of periodic safety update reports, or PSURs.
All new MAAs must include a risk management plan (RMP) describing the risk management system that the company will put in 
place and documenting measures to prevent or minimize the risks associated with the product. The regulatory authorities may also 
impose specific obligations as a condition of the MA. Such risk-minimization measures or post-authorization obligations may include 
additional safety monitoring, more frequent submission of PSURs, or the conduct of additional clinical trials or post-authorization 
safety studies.  
The advertising and promotion of medicinal products is also subject to laws concerning promotion of medicinal products, interactions 
with physicians, misleading and comparative advertising and unfair commercial practices. All advertising and promotional activities 
for the product must be consistent with the approved summary of product characteristics, and therefore all off-label promotion is 
prohibited.  Direct-to-consumer advertising of prescription medicines is also prohibited in the EU. Although general requirements for 
advertising and promotion of medicinal products are established under EU directives, the details are governed by regulations in each 
Member State and can differ from one country to another.
Failure to comply with EU and member state laws that apply to the conduct of clinical trials, manufacturing approval, MA of 
medicinal products and marketing of such products, both before and after grant of the MA, manufacturing of pharmaceutical products, 
statutory health insurance, bribery and anti-corruption or with other applicable regulatory requirements may result in administrative, 
civil or criminal penalties. These penalties could include delays or refusal to authorize the conduct of clinical trials or to grant MA, 
product withdrawals and recalls, product seizures, suspension, withdrawal or variation of the MA, total or partial suspension of 
production, distribution, manufacturing or clinical trials, operating restrictions, injunctions, suspension of licenses, fines and criminal 
penalties.
The aforementioned EU rules are generally applicable in the European Economic Area (EEA) which consists of the 27 EU member 
states plus Norway, Liechtenstein and Iceland.
For other countries outside of the EU, such as countries in Eastern Europe, Latin America or Asia, the requirements governing the 
conduct of clinical trials, product licensing, pricing and reimbursement vary from country to country. In all cases, again, the clinical 
trials are conducted in accordance with GCP and the applicable regulatory requirements and the ethical principles that have their 
origin in the Declaration of Helsinki.
If we fail to comply with applicable foreign regulatory requirements, we may be subject to, among other things, fines, suspension or 
withdrawal of regulatory approvals, product recalls, seizure of products, operating restrictions and criminal prosecution.
Regulation of Companion Diagnostics
In the EU, in vitro diagnostic medical devices were regulated by Directive 98/79/EC which regulated the placing on the market, the 
CE-marking, the essential requirements, the conformity assessment procedures, the registration obligations for manufactures and 
devices as well as the vigilance procedure. In vitro diagnostic medical devices had to comply with the requirements provided for in the 
Directive, and with further requirements implemented at national level (as the case may be). 
The regulation of companion diagnostics is subject to further requirements since the in vitro diagnostic devices Regulation (No 
2017/746) (IVDR) became applicable on May 26, 2022. Following subsequent legislative changes, European institutions adopted a 
“progressive” roll-out of the IVDR to prevent disruption in the supply of in vitro diagnostic medical devices. Therefore, the IVDR 
fully applies as of May 26, 2022 but there is a tiered system extending the grace period for many devices (depending on their risk 
classification) before they have to be fully compliant with the Regulation. The IVDR which introduces a new classification system for 
companion diagnostics which are now specifically defined as diagnostic tests that support the safe and effective use of a specific 
medicinal product, by identifying patients that are suitable or unsuitable for treatment. Companion diagnostics will have to undergo a 
conformity assessment by a notified body. Before it can issue an EU certificate, the notified body must seek a scientific opinion from 
the EMA on the suitability of the companion diagnostic to the medicinal product concerned if the medicinal product falls exclusively 
within the scope of the centralized procedure for the authorization of medicines, or the medicinal product is already authorized 
through the centralized procedure, or a MA application for the medicinal product has been submitted through the centralized 
procedure. For other substances, the notified body can seek the opinion from a national Competent Authorities or the EMA.
The aforementioned EU rules are generally applicable in the EEA.
Brexit and the Regulatory Framework in the United Kingdom

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Since the end of the Brexit transition period on January 1, 2021, and the implementation of the Windsor Framework on January 1, 
2025, the United Kingdom (UK) is not generally subject to EU laws in respect of medicinal products. The EU laws that have been 
transposed into UK law through secondary legislation remain applicable in Great Britain (GB) (England, Scotland and Wales). 
However, new legislation such as the (EU) CTR is not applicable in GB.
The UK Medicines and Medical Devices Act 2021 has introduced delegated powers in favor of the Secretary of State or an 
‘appropriate authority’ to amend or supplement existing regulations in the area of medicinal products and medical devices. This allows 
new rules to be introduced in the future by way of secondary legislation, which aims to allow flexibility in addressing regulatory gaps 
and future changes in the fields of human medicines, clinical trials and medical devices.
Since January 1, 2021, the Medicines and Healthcare products Regulatory Agency (MHRA) has been the UK’s standalone medicines 
and medical devices regulator. As a result of the Northern Ireland Protocol, different rules applied in Northern Ireland than in GB; 
broadly, Northern Ireland continued to follow the EU regulatory regime. However, on January 1, 2025, a new arrangement called the 
“Windsor Framework” came into effect and reintegrated Northern Ireland under the regulatory authority of the MHRA with respect to 
medicinal products. The Windsor Framework removes EU licensing processes, and EU labeling and serialization requirements in 
relation to Northern Ireland, and introduces a UK-wide licensing process for medicinal products. 
The UK regulatory framework in relation to clinical trials is derived from the now-repealed EU Clinical Trials Directive (as 
implemented into UK law, through the Medicines for Human Use (Clinical Trials) Regulations 2004, as amended). The extent to 
which the regulation of clinical trials in the UK will mirror the (EU) CTR in the long term is not yet certain, however, on December 
12, 2024, the UK government introduced a legislative proposal - the Medicines for Human Use (Clinical Trials) Amendment 
Regulations 2024 - that, if implemented, will replace the current regulatory framework for clinical trials in the UK. The legislative 
proposal aims to provide a more flexible regime to make it easier to conduct clinical trials in the UK, increase the transparency of 
clinical trials conducted in the UK and make clinical trials more patient centered. The UK government has provided the legislative 
proposal to the UK Parliament for its review and approval. Once the legislative proposal is approved (with or without amendment), it 
will be adopted into UK law which is expected in early 2026.   
MAs in the UK are governed by the Human Medicines Regulations (SI 2012/1916), as amended. All existing EU MAs for centrally 
authorized products were automatically converted or grandfathered into UK MAs, effective in GB (only), free of charge on January 1, 
2021, unless the MA holder opted-out. Under the terms of the Windsor Framework, these MAs became valid for the whole of the UK 
from January 1, 2025. In order to use the EU centralized procedure to obtain an MA that will be valid throughout the EEA, companies 
must be established in the EEA. Therefore, since Brexit, companies established in the UK can no longer use the EU centralized 
procedure and instead an EEA entity must hold any centralized MAs. In order to obtain a UK MA to commercialize products in the 
UK, an applicant must be established in the UK and must follow one of the UK national authorization procedures or one of the 
remaining post-Brexit international cooperation procedures to obtain an MA to commercialize products in the UK. Applications are 
governed by the Human Medicines Regulations (SI 2012/1916) and are made electronically through the MHRA Submissions Portal. 
The MHRA has introduced changes to national licensing procedures, including procedures to prioritize access to new medicinal 
products that will benefit patients, including a 150-day assessment (subject to clock-stops) and a rolling review procedure. In addition, 
an international recognition procedure (IRP) has been in place since January 1, 2024, whereby the MHRA will have regard to 
decisions on the approval of MAs made by the EMA and certain other regulators when determining an application for a new UK MA. 
Pursuant to the IRP, the MHRA will take into account the expertise and decision-making of trusted regulatory partners (i.e., the 
regulators in Australia, Canada, Switzerland, Singapore, Japan, the U.S. and the EU). The MHRA will conduct a targeted assessment 
of IRP applications but retain the authority to reject applications if the evidence provided is considered insufficiently robust. The IRP 
allows medicinal products approved by such trusted regulatory partners that meet certain criteria to undergo a fast-tracked MHRA 
review to obtain and/or update an MA in the UK. Applications should be decided within a maximum of 60 days if there are no major 
objections identified that cannot be resolved within such 60-day period and the approval from the trusted regulatory partner selected 
has been granted within the previous 2 years or if there are such major objections identified or such approval has not been granted 
within the previous 2 years within 110 days. Applicants can submit initial MAAs to the IRP but the procedure can also be used 
throughout the lifecycle of a product for post-authorization procedures including line extensions, variations and renewals. In the UK, 
the initial duration of an MA is five years and following renewal will be valid for an unlimited period unless the MHRA decides on 
justified grounds relating to pharmacovigilance, to proceed with only one additional five-year renewal. Any authorization which is not 
followed by the actual placing of the medicinal product on the market in the UK within three (3) years shall cease to be in force.
There is no pre-MA orphan designation in the UK. Instead, the MHRA reviews applications for orphan designation in parallel to the 
corresponding MA application. The criteria are essentially the same, but have been tailored for the market, i.e., the prevalence of the 
condition in the UK, rather than the EU, must not be more than five in 10,000. Should an orphan designation be granted, the period or 
market exclusivity will be set from the date of first approval of the product in the UK.
 

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Other Healthcare Laws 
In addition to FDA restrictions on marketing of pharmaceutical and biological products, other U.S. federal and state healthcare 
regulatory laws restrict business practices in the biopharmaceutical industry, which include, but are not limited to, state and federal 
anti-kickback, false claims, data privacy and security, and physician payment and drug pricing transparency laws. Similar laws exist in 
foreign jurisdictions as well.
The federal Anti-Kickback Statute prohibits, among other things, any person or entity from knowingly and willfully offering, paying, 
soliciting, receiving or providing any remuneration, directly or indirectly, overtly or covertly, 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, in whole or in 
part, 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 
the one hand and prescribers, purchasers, and formulary managers on the other. Although there are a number of statutory exceptions 
and regulatory safe harbors protecting some common activities from prosecution, the exceptions 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 meet the requirements of a statutory or regulatory exception or safe harbor. Failure to meet all of the 
requirements of a particular applicable statutory exception or regulatory safe harbor does not make the conduct per se illegal under the 
Anti-Kickback Statute. Instead, the legality of the arrangement will be evaluated on a case-by-case basis based on a cumulative review 
of all its facts and circumstances. 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. 
Additionally, a person or entity does not need to have actual knowledge of the statute or specific intent to violate it in order to have 
committed a violation. The majority of states also have anti-kickback laws, which establish similar prohibitions and in some cases 
may apply to items or services reimbursed by any third-party payor, including commercial insurers. 
The federal false claims laws, including the civil False Claims Act, prohibit any person or entity from, among other things, knowingly 
presenting, or causing to be presented, a false, fictitious or fraudulent claim for payment to, or approval by, the federal government, 
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, or from knowingly making a false statement to avoid, decrease or conceal an obligation to pay money to the U.S. 
federal government. A claim includes “any request or demand” for money or property presented to the U.S. government. In addition, 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 federal civil False Claims Act. Actions under the civil False Claims Act may be brought by the Attorney General 
or as a qui tam action by a private individual in the name of the government. Violations of the civil False Claims Act can result in very 
significant monetary penalties and treble damages. Several pharmaceutical and other healthcare companies have been prosecuted 
under these laws for, among other things, 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 (e.g., off-label) uses. In addition, the civil monetary penalties statute 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. Many states also 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. Given the significant size of actual and potential settlements, it is expected that the 
government authorities will continue to devote substantial resources to investigating healthcare providers’ and manufacturers’ 
compliance with applicable fraud and abuse laws.
 
The federal Health Insurance Portability and Accountability Act of 1996 (HIPAA) created additional federal criminal statutes that 
prohibit, among other actions, knowingly and willfully executing, or attempting to execute, a scheme to defraud any healthcare benefit 
program, including private third-party payors, knowingly and willfully embezzling or stealing from a healthcare benefit program, 
willfully obstructing a criminal investigation of a healthcare offense, 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. Similar to the U.S. federal Anti-Kickback Statute, a person or entity does not need to have actual 
knowledge of the statute or specific intent to violate it in order to have committed a violation. 
In addition, there has been a recent trend of increased federal and state regulation of payments made to physicians and certain other 
healthcare providers. The ACA imposed, among other things, new annual reporting requirements through the Physician Payments 
Sunshine Act for covered manufacturers for certain payments and “transfers of value” provided to physicians (defined to include 
doctors, dentists, optometrists, podiatrists and chiropractors), certain non-physician practitioners including physician assistants and 
nurse practitioners, and teaching hospitals, as well as ownership and investment interests held by physicians, as defined by statute, and 
their immediate family members. Failure to submit timely, accurately and completely the required information for all payments, 
transfers of value and ownership or investment interests may result in civil monetary penalties. Covered manufacturers must submit 
reports by the 90th day of each subsequent calendar year. In addition, certain states require implementation of compliance programs 
and compliance with the pharmaceutical industry’s voluntary compliance guidelines and the relevant compliance guidance 
promulgated by the federal government, impose restrictions on marketing practices, and/or tracking and reporting of pricing and 
marketing information as well as gifts, compensation and other remuneration or items of value provided to physicians and other 
healthcare professionals and entities.

39
 
 
Violations of any of these laws or any other governmental regulations that may apply may result in significant penalties, including, 
without limitation, administrative, civil and criminal penalties, damages, fines, disgorgement, contractual damages, reputational harm, 
diminished profits and future earnings, the curtailment or restructuring of our operations, exclusion from participation in federal and 
state healthcare programs, reporting obligations and oversight if we become subject to a corporate integrity agreement or other 
agreement is required, and/or individual imprisonment. 
 
To the extent that any of our antibody candidates, once approved, 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 other transfers of value to 
healthcare professionals. 
Privacy and Data Protection Laws in the United States
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 for Economic and Clinical Health Act (HITECH) and their 
respective implementing regulations, impose specified requirements relating to the privacy, security and transmission of individually 
identifiable health information held by covered entities and their business associates. Among other things, HITECH made HIPAA’s 
security standards directly applicable to “business associates,” defined as independent contractors or agents of covered entities that 
create, receive, maintain or transmit protected health information in connection with providing a service for or 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 of health information in certain circumstances, many of which differ from each other in 
significant ways and may not have the same requirements, thus complicating compliance efforts. By way of example, the California 
Consumer Privacy Act of 2018, as amended by the California Privacy Rights Act (collectively, the CCPA) requires covered 
businesses that process the personal information of California residents to, among other things: (i) provide certain disclosures to 
California residents regarding the business’s collection, use, and disclosure of their personal information; (ii) receive and respond to 
requests from California residents to access, delete, and correct their personal information, or to opt out of certain disclosures of their 
personal information; and (iii) enter into specific contractual provisions with service providers that process California resident 
personal information on the business’s behalf. Additional compliance investment and potential business process changes may also be 
required. Similar laws have passed in Virginia, Connecticut, Utah and Colorado, and have been proposed in other states and at the 
federal level, reflecting a trend toward more stringent privacy legislation in the United States. The enactment of such laws could have 
potentially conflicting requirements that would make compliance challenging.
Privacy and Data Protection Laws in Europe 
We are subject to European laws relating to our and our suppliers’, collaborators’ and subcontractors’ (where they act as processors) 
collection, control, processing and other use of personal data (i.e., any data relating to an identifiable living individual, whether that 
individual can be identified directly or indirectly). We are subject to the supervision of local data protection authorities in those 
jurisdictions where we are established, and where we process personal data in the context of the activities of that establishment (e.g., 
undertaking clinical trials). We and our suppliers, collaborators and subcontractors process personal data including in relation to our 
employees, employees of customers, clinical trial patients, healthcare professionals and employees of suppliers including health and 
medical information. The data privacy regime in the EU includes the General Data Protection Regulation (GDPR) and national laws 
and regulations implementing or supplementing it. 
The GDPR requires that personal data is only collected for specified, explicit and legal purposes as set out in the GDPR or local laws, 
and the data may then only be processed in a manner compatible with those purposes. The personal data collected and processed must 
be adequate, relevant and not excessive in relation to the purposes for which it is collected and processed, it must be held securely, not 
transferred outside of the European Economic Area (EEA) unless certain steps are taken to ensure an adequate level of protection, and 
must not be retained for longer than necessary for the purposes for which it was collected. In addition, the GDPR requires companies 
processing personal data to take certain organizational steps to ensure that they have adequate records, policies, security, training and 
governance frameworks in place to ensure, and to be able to demonstrate, protection. For example, the GDPR requires us to make 
more detailed disclosures to data subjects, requires disclosure of the legal basis on which we can process personal data, makes it 
harder for us to obtain valid consent for processing, may require the appointment of a data protection officer where sensitive personal 
data (i.e., health data) is processed on a sufficiently large scale, introduces mandatory data breach notification throughout the EU and 
imposes additional obligations on us when we are contracting with certain service providers. 
In addition, to the extent a company processes, controls or otherwise uses “special category” personal data (including patients’ health 
or medical information, genetic information and biometric information), more stringent rules apply, further limiting the circumstances 

40
and the manner in which a company is legally permitted to process that data. The GDPR provides a broad right for EU and EEA 
member states to create supplemental national laws which may result in divergence across Europe making it harder to maintain a 
consistent operating model or standard operating procedures. Such laws, for example, may relate to the processing of health, genetic 
and biometric data, which could further limit our ability to use and share such data or could cause our costs to increase, and harm our 
business and financial condition. 
There are costs and administrative burdens associated with compliance with the GDPR and the resultant changes in the EU and EEA 
member states’ national laws. Any failure or perceived failure to comply with global privacy laws carries with it the risk of significant 
penalties and sanctions of up to €20 million or up to 4% of total worldwide annual turnover of the preceding financial year. 
Additionally, following the United Kingdom’s withdrawal from the EEA and the EU, and the expiry of the transition period, 
companies have to comply with the GDPR and the GDPR as incorporated into United Kingdom national law, the latter regime having 
the ability to separately fine up to the greater of €20 million (£17.5 million) or 4% of global turnover. These laws or new 
interpretations, enactments or supplementary forms of these laws, could create liability for us, could impose additional operational 
requirements on our business, could affect the manner in which we use and transmit patient information and could increase our cost of 
doing business. Claims of violations of privacy rights or contractual breaches, even if we are not found liable, could be expensive and 
time-consuming to defend and could result in adverse publicity that could harm our business.
Among other requirements, the GDPR regulates transfers of personal data subject to the GDPR to third countries that have not been 
found to provide adequate protection to such personal data, including the United States, and the efficacy and longevity of current 
transfer mechanisms between the EEA, and the United States remains uncertain. Case law from the Court of Justice of the European 
Union (CJEU) states that reliance on the standard contractual clauses - a standard form of contract approved by the European 
Commission as an adequate personal data transfer mechanism - alone may not necessarily be sufficient in all circumstances and that 
transfers must be assessed on a case-by-case basis. On July 10, 2023, the European Commission adopted its Adequacy Decision in 
relation to the new EU-US Data Privacy Framework (DPF), rendering the DPF effective as a GDPR transfer mechanism to U.S. 
entities self-certified under the DPF. 
These recent developments may require us to review and amend the legal mechanisms by which we make and/ or receive personal 
data transfers to/ in the U.S.  As supervisory authorities issue further guidance on personal data export mechanisms, including 
circumstances where the standard contractual clauses cannot be used, and/or start taking enforcement action, we could suffer 
additional costs, complaints and/or regulatory investigations or fines, and/or if we are otherwise unable to transfer personal data 
between and among countries and regions in which we operate, it could affect the manner in which we provide our services, the 
geographical location or segregation of our relevant systems and operations, and could adversely affect our financial results.
From January 1, 2021, we are subject to the GDPR and also the United Kingdom (UK) GDPR, which, together with the amended UK 
Data Protection Act 2018, retains the GDPR in UK national law. On October 12, 2023, the UK Extension to the DPF came into effect 
(as approved by the UK Government), as a data transfer mechanism from the UK to U.S. entities self-certified under the DPF. As we 
continue to expand into other foreign countries and jurisdictions, we may be subject to additional laws and regulations that may affect 
how we conduct business.
Coverage and Reimbursement 
Significant uncertainty exists as to the coverage and reimbursement status of any pharmaceutical or biological products for which we 
obtain regulatory approval. In the United States and markets in other countries, patients who are prescribed treatments for their 
conditions and providers performing the prescribed services generally rely on third-party payors to reimburse all or part of the 
associated healthcare costs. Patients are unlikely to use our products unless coverage is provided and reimbursement is adequate to 
cover a significant portion of the cost of our products. Sales of any products for which we receive regulatory approval for commercial 
sale will therefore depend, in part, on the availability of coverage and adequate reimbursement from third-party payors. Third-party 
payors include government authorities, managed care plans, private health insurers and other organizations. 
In the United States, the process for determining whether a third-party payor will provide coverage for a pharmaceutical or biological 
product typically is separate from the process for setting the price of such product or for establishing the reimbursement rate that the 
payor will pay for the product once coverage is approved. For products administered under the supervision of a physician, obtaining 
coverage and adequate reimbursement may be particularly difficult because of the higher prices often associated with such drugs. 
Additionally, separate reimbursement for the product itself or the treatment or procedure in which the product is used may not be 
available, which may impact physician utilization. A decision by a third-party payor not to cover our bispecific antibody candidates 
could reduce physician utilization of our products once approved and have a material adverse effect on our sales, results of operations 
and financial condition. Moreover, a third-party payor’s decision to provide coverage for a pharmaceutical or biological product does 
not imply that an adequate reimbursement rate will be approved. Adequate third-party reimbursement may not be available to enable 
us to maintain price levels sufficient to realize an appropriate return on our investment in product development. Additionally, coverage 
and reimbursement for new products can differ significantly from payor to payor. One third-party payor’s decision to cover a 

41
particular medical product or service does not ensure that other payors will also provide coverage for the medical product or service, 
or will provide coverage at an adequate reimbursement rate. As a result, the coverage determination process will require us to provide 
scientific and clinical support for the use of our products to each payor separately and will be a time-consuming process. 
In the EU, governments influence the price of products through their pricing and reimbursement rules and control of national health 
care systems that fund a large part of the cost of those products to consumers. Member states are free to restrict the range of 
pharmaceutical products for which their national health insurance systems provide reimbursement, and to control the prices and 
reimbursement levels of pharmaceutical products for human use. Some jurisdictions operate positive and negative list systems under 
which products may only be marketed once a reimbursement price has been agreed to by the government. Member states may approve 
a specific price or level of reimbursement for the pharmaceutical product, or alternatively adopt a system of direct or indirect controls 
on the profitability of the company responsible for placing the pharmaceutical product on the market, including volume-based 
arrangements, caps and reference pricing mechanisms. To obtain reimbursement or pricing approval, some of these countries may 
require the completion of clinical trials that compare the cost effectiveness of a particular product candidate to currently available 
therapies. Other member states allow companies to fix their own prices for medicines, but monitor and control company profits. The 
downward pressure on health care costs in general, particularly prescription products, has become very intense. As a result, 
increasingly high barriers are being erected to the entry of new products. In addition, in some countries, cross border imports from 
low-priced markets exert a commercial pressure on pricing within a country.
The containment of healthcare costs has become a priority of federal, state and foreign governments, and the prices of pharmaceutical 
or biological products have been a focus in this effort. Third-party payors are increasingly challenging the prices charged for medical 
products and services, examining the medical necessity and reviewing the cost-effectiveness of pharmaceutical or biological products, 
medical devices and medical services, in addition to questioning safety and efficacy. If these third-party payors do not consider our 
products to be cost-effective compared to other available therapies, they may not cover our products after FDA approval or, if they do, 
the level of payment may not be sufficient to allow us to sell our products at a profit. 
Healthcare Reform 
A primary trend in the U.S. healthcare industry and elsewhere is cost containment. Government authorities and other third-party 
payors have attempted to control costs by limiting coverage and the amount of reimbursement for particular medical products. For 
example, in March 2010, the ACA was enacted, which, among other things, increased the minimum Medicaid rebates owed by most 
manufacturers under the Medicaid Drug Rebate Program; introduced 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; extended 
the Medicaid Drug Rebate Program to utilization of prescriptions of individuals enrolled in Medicaid managed care plans; subjected 
drug manufacturers to new annual fees based on pharmaceutical companies’ share of sales to federal healthcare programs; and created 
a new Patient Centered Outcomes Research Institute to oversee, identify priorities in, and conduct comparative clinical effectiveness 
research, along with funding for such research. 
Since its enactment, there have been judicial, executive and Congressional challenges to certain aspects of the ACA. On June 17, 
2021, the U.S. Supreme Court dismissed the most recent judicial challenge to the ACA brought by several states without specifically 
ruling on the constitutionality of the ACA.   
In addition, the American Rescue Plan Act of 2021 as signed into law, which eliminated the statutory Medicaid drug rebate cap, 
beginning January 1, 2024. The rebate was previously capped at 100% of a drug’s AMP. Moreover, recently there has been 
heightened governmental scrutiny over the manner in which manufacturers set prices for their marketed products, which have resulted 
in several recent Congressional inquiries and proposed and enacted legislation designed to, among other things, bring more 
transparency to product pricing, review the relationship between pricing and manufacturer patient programs, and reform government 
program reimbursement methodologies for pharmaceutical and biological products. Most recently, on August 16, 2022 the Inflation 
Reduction Act of 2022 (“IRA”) was signed into law. Among other things, the IRA requires manufacturers of certain drugs to engage 
in price negotiations with Medicare (beginning in 2026), with prices that can be negotiated subject to a cap; imposes rebates under 
Medicare Part B and Medicare Part D to penalize price increases that outpace inflation (first due in 2023); and replaces the Part D 
coverage gap discount program with a new discounting program (which began in 2025). The IRA permits the Secretary of the 
Department of Health and Human Services (HHS) to implement many of these provisions through guidance, as opposed to regulation, 
for the initial years. The Centers for Medicare & Medicaid Services (CMS) has published the negotiated prices for the initial ten 
drugs, which will first be effective in 2026, and the list of the subsequent 15 drugs that will be subject to negotiation, although the 
Medicare drug price negotiation program is currently subject to legal challenges. For that and other reasons, it is currently unclear how 
the IRA will be effectuated, and the impact of the IRA on the pharmaceutical industry cannot yet be fully determined. Individual states 
in the United States have also become increasingly active 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. The implementation of cost containment measures or other healthcare reforms may prevent us 
from being able to generate revenue, attain profitability or commercialize our drugs. 

42
We expect that additional state, federal and foreign 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 products once approved or additional pricing pressures. Any reduction in reimbursement from Medicare or other government-
funded programs may result in a similar reduction in payments from private payors.
Employees
As of January 1, 2025, we had 260 employees, including 61 part-time employees and 105 employees with M.D. or Ph.D. degrees. Of 
these employees, 70 are employees of Merus US Inc., 190 were primarily engaged in research and development activities and 70 were 
primarily engaged in general and administrative activities. Further, we had 112 employees identifying as male and 148 identifying as 
female and with over 30 different nationalities represented. None of our employees are part of a labor union, and we consider our 
employee relations to be good.
Our Values and Culture
Our goal is to help patients overcome the devastating disease of cancer. Our values reflect the way we go about achieving this goal. It 
is a declaration both of who we are and who we want to be. These are principles we strive to live up to and to be measured by:
•
We are creative problem solvers – we nurture inquisitive minds and diverse talents, to create solutions to some of today’s 
most pressing medical needs in oncology. We accept setbacks as an inevitable part of innovation, and we welcome them as 
an opportunity to learn.
•
We commit and move as one – we are one company with a common goal of closing in on cancer. We work as a team and 
encourage a broad and varied perspectives. When we take a decision, we unite and move forward together.
•
We aim at excellence – our work impacts lives. We honor this with our every decision and take collective responsibility to 
uphold our goal. We strive to do the right things and take pride in doing them well.
•
We care – everything we do, we do because we care. We care deeply about improving patients’ lives. We respect and support 
each other and the communities around us.
We believe our values are an important facet of who we are and how we will deliver on our goals to close in on cancer, and meet our 
mission.

43
Code of Business Conduct and Ethics
All employees are expected to conduct business with the highest standard of business ethics. Each employee receives and we ask each 
employee to agree to follow the Merus Code of Business Conduct and Ethics. Employees are encouraged to discuss any related 
concerns, including with management or report concerns anonymously through an Ethics Hotline. Any report received on the Ethics 
Hotline is investigated by our General Counsel or the Audit Committee, as applicable. Further, we have two employee confidential 
advisors, as well as an external confidential advisor, with whom our employees may discuss ways of addressing, preventing and 
combating inappropriate behavior in the workplace. No one shall be subject to adverse action who in good faith reports an incident of 
violation of our policies, provides information, or otherwise assists in any investigation. Any employee who retaliates against another 
in violation of our policies will be subjected to disciplinary action, up to and including termination. 
As part of its regular review of the corporate governance policies of Merus N.V., our board of directors, with consent of the 
Company’s Works Council adopted and approved the updated and amended Company Code of Business Conduct and Ethics (the 
"Business Code") effective January 15, 2024. The Business Code supersedes the previous version and reflects, among other things, 
certain updates which we believe are consistent with current governance best practices.
The amendments include revisions to Annex I of the Business Code to align with the Dutch Whistleblower Protection Act (wet 
bescherming klokkenluiders) (“WPA”), including (i) an updated internal reporting procedure; (ii) the manner in which suspected 
wrongdoing outside the organization can be reported to competent authorities and, where applicable, to institutions, bodies, offices 
and agencies of the European Union; and (iii) enhancements and clarifications related to the protection and confidentiality afforded to 
those reporting a suspicion of wrongdoing under the Business Code.
Employership, Leadership and Training 
We perform periodic surveys, which give employees the opportunity to provide feedback on our employee engagement, commitment, 
leadership, work atmosphere, role clarity, psychological security, and employership, as well as annual surveys of a smaller scope. 
These surveys are managed by a third-party vendor to encourage openness and honesty in responding to questions regarding these 
important factors. In 2024, our employee response rate to our biannual survey was 91 percent, which we believe is an indication that 
our employees recognize that their feedback is important. Further, we were named a “World-Class Workplace” by the third-party 
vendor based on the outcome of the employee engagement survey, which demonstrated that Merus scored above other companies in 
the Netherlands on aspects of employership themes and how likely is it that an employee would recommend Merus as an employer to 
others. Further, we scored higher marks on pride of organization, inspiring vision of the future, leadership, work atmosphere and 
satisfaction about the organization than benchmarks for employership established by the vendor through its survey results based on 
average scores across surveys from over 500 other organizations.
Critical to our success is the hiring, training, retention and promotion of our employees, as we develop the competencies needed for 
the advancement of our company today and that will be needed in the coming years.  Accordingly, we developed a variety of 
leadership and development opportunities under an umbrella program we refer to as the Merus Academy. A pillar of this program is a 
leadership development program, where we work with a third-party provider to help train and enhance the leadership skills of 

44
employees at the director to vice president level. Another pillar is a leadership essentials training, which we offer to our scientists to 
help enhance their individual effectiveness, improve leadership ability, develop skills to address change and conflict management, and 
enhance their thought leadership within the organization. A third pillar is our implementation of an online learning platform, which 
offers our employees training courses across a variety of disciplines. Each of these pillars supports our talent management and 
advancement to drive our corporate goals.
Equal Opportunity
 
We are an equal employment opportunity employer that does not discriminate on the basis of actual or perceived race, color, religious 
creed, national origin, sex (including pregnancy, childbirth, and related medical conditions), sexual orientation, age, ancestry, 
disability or perceived disability, qualified handicap, gender identity, military status, veteran status, certain criminal records, genetic 
information or testing, HIV testing, or any other characteristic protected by applicable federal, state or local laws (each, a “Protected 
Characteristic”). We are dedicated to this policy with respect to recruitment, hiring, placement, promotion, transfer, training, 
compensation, benefits, employee activities and general treatment during employment. Equal opportunities are important to us. To 
evaluate our performance, we asked an external party to assess whether there is a difference in compensation of men and women at 
Merus. The outcome of the assessment was that there was not different compensation between men and women in comparable 
positions/roles within Merus. Equal opportunity is also reflected in our Management Team, and in our Board. 
Compensation Philosophy, Incentives and Retention
Our human capital strategies, hiring and retention outcomes are reviewed on a regular basis with our board of directors, to align with 
our overall business strategies. Further, we review our compensation philosophy annually with the compensation committee of our 
board of directors, as well as on an ad hoc basis to receive input on new hires during the course of the year. Our compensation 
committee, relying on their extensive experience in the biopharmaceutical industry and receiving input from our external 
compensation advisors, review our short and long term incentive programs, and evaluate our group of peer companies to help achieve 
our hiring and retention goals during the course of the year. Our board of directors receives regular updates on these objectives, 
including headcount plans, achievement against goals and attrition rates during the year.
Health and Safety
The health and safety of our employees is a top priority. We have implemented workforce policies for our headquarters in the 
Netherlands, as well as our subsidiary in Cambridge, Massachusetts, for taking measures to comply with changing rules, regulations 
and recommendations by the  U.S. Center for Disease Control and Prevention (CDC) and European local health agencies, including 
the Dutch National Institute for Health and Environment or Het Rijksinstituut voor Volksgezondheid en Milieu (RIVM), and local 
regulations as may apply to the health and safety of our employees. For those employees working at our offices and laboratory in 
Utrecht, they are required to follow requirements consistent with the guidance provided by the RIVM for the Netherlands, and 
employees of our subsidiary Merus US, Inc. are required to abide by the guidelines of the CDC, and Federal, state and local 
regulations for the U.S. 
Employee Health and Wellbeing Support
 
Healthy and happy employees are important to us and therefore we have launched several initiatives to be able to support our 
employees with health and wellbeing. One of these initiatives is the option for employees that are experiencing financial difficulties on 
a personal level due to the current challenging economic circumstances, to get support from an external provider to get better insight 
in their financial situation and help them to set up a plan and/or take next steps to deal with these financial difficulties. 
In addition, we offer our employees a medical check and/or a so-called fit-test to check-in and get advice on their overall health. We 
also offer our employees the option of a consult with an ergonomist to ensure their in-office workplace is correctly set up to limit the 
possibility of workplace related health issues from occurring. 
Sustainability and Community Relations
At Merus, we want to play a positive role in society, not only by developing potentially meaningful medicines, but also by aiming to 
be responsible for the impact of our operations on the environment. To contribute to that goal, we have a sustainability team, operating 
on a volunteer basis and comprised of members from different business functions throughout the organization. Its mission is to reduce 
Merus' environmental impact and increase employee awareness about sustainability through a variety of initiatives in our offices and 
laboratories.
We work with the on-premises catering company to continue to deliver vegan and vegetarian-only options daily. Fruit and vegetables 
provided by our caterer are also locally sourced, reducing energy consumption expended in their transport.  

45
We also have selected our coffee vendor for its sustainability practices, which reports using techniques such as recirculation of heat in 
the coffee roasting process, to save up to 75% of energy expenditure, and uses 100% traceable Dutch wind energy. The roastery 
reports having a climate-resistant garden with rainwater infiltration. For carbon emissions that cannot be (yet) avoided, the supplier 
notes that it compensates through fairtrade carbon credits in the coffee chain. The supplier also aims to reduce waste: coffee beans are 
delivered in bulk in aluminum-free bags, and coffee machines are refurbished at the end of their lifecycle.  
We have also implemented a sustainable mobility plan referred to as the Merus Employee Cycling Plan, which supports employees to 
purchase a new or second hand (e-)bike to commute to Merus, thereby reducing our carbon footprint, lowering city traffic, congestion, 
and improving the vitality of our employees. In 2024, 12 employees took part in the Merus Employee Cycling Plan, and 50 employees 
have been using an NS business card as part of our offerings to further reduce car usage. This card enables our employees to come to 
work through public transportation in the Netherlands, helping to reduce emissions and the impact of congestion in the Netherlands 
and the Utrecht Science Park. 
In 2024, we also donated 150 trees to Trees for All, on behalf of our employees, contributing to reforestation projects in the 
Netherlands. This program supports local, sustainable agriculture projects and helps increase the income of farmers, while protecting 
and preserving nearby forest areas. Merus has contributed to this program since 2019, resulting in planting approximately 750 trees 
during this time. 
In an effort to reduce electronic waste (e-waste), since 2022, we have introduced a new fleet of laptops with an extended lifecycle of 
four years, to replace our previous three-year lifecycle equipment. In 2024, we also donated 25 electronic devices, including phones, 
laptops, chargers, and hard drives. to Close the Gap – an international social enterprise whose goal is to collect high-quality IT devices 
and offer them to educational, medical and social projects in developing and emerging countries. For its laptop bags, we have opted 
for a supplier which produces sustainable bags made from recycled PET bottles. In 2023, we also opted for 100% recycled paper for 
all in-office printing.   
In our laboratories in Utrecht, recycling efforts are encouraged as much as possible, in alignment with laboratory procedures. To 
improve plastic waste management, plastic bottles are reused as waste bins. These plastic bottles are stored for reuse in dedicated 
spaces throughout the laboratories. In 2023, we switched to a more sustainable waste bin made from recycled polypropylene for the 
biological waste in our laboratories. In our offices in Utrecht, waste bins have been installed to allow waste separation (paper, plastic, 
and general waste) and to facilitate recycling efforts.  
We are proud to have received the Sustainable Aviation Fuel (SAF) certificate from KLM/BlueBiz, recognizing our commitment to 
reducing CO₂ emissions from business travel. By participating in KLM’s Corporate SAF program, we support the use of sustainable 
aviation fuel, which produces at least 75% less CO₂ than traditional fossil jet fuel.
The "Accelerator": a New Sustainable Merus Utrecht Headquarters
 
Since December 2022, we have been located at our headquarters called the "Accelerator" in the Utrecht Science Park, at 17 
Uppsalalaan, 3rd and 4th floor, 3583 CT, Utrecht. This building meets the requirements of the so-called ‘BREEAM Excellent’ 
certification. BREEAM (Building Research Establishment’s Environmental Assessment Method) is a method to measure and assess 
the sustainability of real estate and is used in over 80 countries worldwide. The method was originally developed by the Building 
Research Establishment (BRE) and the Dutch Green Building Council (DGBC) has adopted the method to make it align with the 
situation in The Netherlands, creating BREEAM-NL. There are specific BREEAM schemes for new buildings, existing (in-use) 
building and demolition to tailor the measurements and assessment to the relevant situation. BREEAM certifications are issued by the 
DGBC.  BREEAM covers a variety of topics and processes, such as the management of the development/built process, a healthy 
internal building climate, energy efficiency, transport to, from and in the building, water usage and waste. The BREEAM certification 
achieved by the Accelerator is the second highest certification that can be obtained and represents high sustainability performance of 
the building and the use of best practices in the market to build a building that meets this certification level. Only about 10% of all 
office buildings in the Netherlands are certified as ‘BREEAM Excellent.’ 
To receive the BREEAM Excellence certification a building needs to have a minimum score of 70%. Based on the bespoke scheme 
used for the assessment of the Accelerator, the Accelerator scored 72.81% granting it a BREEAM Excellent certification. Certain 
notable sustainable features of the Accelerator include: (i) solar paneled roof to provide electrical power; (ii) heating and cooling 
provided by heat pump to avoid gas usage; (iii) LED lighting, including presence detection to avoid use of energy when spaces are 
vacant; and (iv) air handling units with energy recovery.
As part of the BREEAM certification of the Accelerator, the landlord entered into a so-called green lease with each tenant, which 
provides requirements that need to be met by the tenants with regard to the design of the tenant’s premises and the use of the building. 
The green lease includes requirements concerning among others, heating/cooling, transport and lighting used in and around the 
building/tenant’s premises.
Environmental, Health and Safety Supplier Standards
 

46
We adopted the Merus Supplier Standards in September, 2021, to safeguard that our suppliers meet an acceptable standard business 
conduct and compliance with laws and regulations.  These standards apply to our non-clinical and non-research-related 
products/services suppliers that provide products and/or services above a minimum threshold value, and to any sub-contractors of a 
supplier that are involved in the performance of any agreement between Merus and such supplier. For higher value contracts, the 
Supplier Standards form a condition precedent to soliciting bids and proposals from suppliers and are shared with the supplier for 
review and confirmation of compliance as part of the bid or proposal. 
The Supplier Standards includes a range of standards which vary from compliance with law, any privacy regulations to fair 
competition and employment. In short, based on the Supplier Standards, we expect our suppliers (i) to fully comply with applicable 
laws, rules and regulations; (ii) to not have any involvement of any kind with or link to bribery or corruption and to abide by all 
applicable anti-bribery and corruption laws and regulations such as the Foreign Corrupt Practices Act of 1977, as amended, 15 
U.S.C. §§ 78dd-1, et seq. (FCPA) and UK Bribery Act 2010; (iii) to conduct business in a transparent way, keep their records 
accurate and not engage in or facilitate any form of money laundering; (iv) to use fair business practices and act in accordance with 
applicable antitrust laws; (v) to inform Merus in case of a (potential) conflict of interest; (vi) to respect the right to privacy of 
individuals, operate in a manner that is consistent with applicable data protection laws and process personal data provided by Merus 
with strict confidentiality and only when having the appropriate technical and organizational structures and procedures in place to 
ensure the protection of the personal data; (vii) to uphold human rights, pay fair wages, respect rights of workers and to not use any 
forced or child labor of any sort; and (viii) to provide a safe and healthy environment and operate in a socially and environmentally 
responsible manner. Suppliers of Merus must also (i) comply with any applicable federal, state, (inter)national and local 
environmental and health & safety laws and regulations (which include but are not limited to rules on waste, air emissions and 
hazardous substances), obtain and maintain the required permits, licenses, authorizations and registrations and follow their operational 
and reporting requirements and restrictions; (ii) provide a healthy and safe workplace for its employees and other personnel; and (iii) 
operate in a socially and environmentally responsible manner and take measures to proactively protect and minimize the adverse 
impact of its business on the community, environment and natural resources, while safeguarding the health and safety of the public. 
Suppliers are encouraged to conserve natural resources, to avoid the use of hazardous materials where possible and to engage in 
activities that reuse and recycle. 
Corporate Information
We were incorporated as Merus B.V. under the laws of the Netherlands on June 16, 2003. Our principal executive offices are located 
at Uppsalalaan 17, 3584 CT Utrecht, The Netherlands. Our telephone number at the Utrecht address is +31 30 253 8800. Our website 
address is www.merus.nl. Information contained on, or that can be accessed through, our website does not constitute a part of this 
Annual Report on Form 10-K. We have included our website address in this Annual Report on Form 10-K solely as an inactive textual 
reference.
Available Information
We file electronically with the SEC our annual reports on Form 10-K, quarterly reports on Form 10-Q, current reports on Form 8-K, 
proxy statements and other information. Our SEC filings are available to the public over the Internet at the SEC's website at 
http://www.sec.gov. We make available on our website at www.merus.nl, under “Investors & Media,” free of charge, copies of these 
reports and amendments thereto as soon as reasonably practicable after filing or furnishing these reports with the SEC.

47
Item 1A. Risk Factors.
RISK FACTORS
Investing in our common shares involves a high degree of risk. You should consider carefully the risks described below, together with 
the other information included or incorporated by reference in this Annual Report on Form 10-K. If any of the following risks occur, 
our business, financial condition, results of operations and future growth prospects could be materially and adversely affected. In 
these circumstances, the market price of our common shares could decline. Other events that we do not currently anticipate or that we 
currently deem immaterial may also affect our business, prospects, financial condition and results of operations.
Risks Related to Our Business and Industry
We are an company and have incurred significant losses since our inception. We expect to incur losses for the foreseeable future 
and may never achieve or maintain profitability.
We are an oncology company with a limited operating history. We have incurred net losses of $215.3 million, $154.9 million and 
$131.2 million for the years ended December 31, 2024, 2023, and 2022, respectively. As of December 31, 2024, we had an 
accumulated deficit of $968.4 million. Our losses have resulted principally from expenses incurred in research and development of our 
antibody candidates and from management and administrative costs and other expenses that we have incurred while building our 
business infrastructure. We expect to continue to incur significant expenses and operating losses for the foreseeable future as we 
continue to advance our antibody candidates from discovery through pre-clinical development and into clinical trials and seek 
regulatory approval and pursue commercialization of any approved antibody candidates. We anticipate that we will continue to incur 
significant expenses as we:
•
Support the commercial transition of zenocutuzumab to PTx, for PTx to commercialize zenocutuzumab in the approved 
indications of the treatment of pancreatic adenocarcinoma or NSCLC that are advanced unresectable or metastatic and harbor 
a neuregulin 1 (NRG1) gene fusion who have disease progression on or after prior systemic therapy, and continue to explore 
potential development of zenocutuzumab outside the field of NRG1+ cancer;
•
conduct our ongoing Phase 1/2 clinical trial of MCLA-158 or petosemtamab for the treatment of solid tumors;
•
conduct our ongoing LiGeR-HN1 and LiGeR-HN2 phase three clinical trials of petosemtamab in 1L r/m PD-L1+ HNSCC 
and 2/3L r/m HNSCC respectively;
•
conduct our ongoing Phase 1/2 clinical trial for MCLA-129 for the treatment of solid tumors, which is subject to a 
collaboration with Betta, whereby Betta has exclusive rights to develop MCLA-129 in China, and Merus retains all rights ex-
China;
•
continue the research and development of our other pre-clinical antibody candidates;
•
expand our clinical programs to explore new potential combination therapies or indications;
•
expand and enhance our technology platforms, including our Biclonics® technology platform which generates our pipeline of 
bispecific product candidates, our Triclonics® technology platform, which generates pre-clinical trispecific candidates and 
generate and develop additional multispecific antibody candidates; and our ADClonics® technology platform, which 
generates pre-clinical multispecific ADC candidates;
•
seek regulatory approvals for any antibody candidates that successfully complete clinical trials;
•
potentially establish a sales, marketing and distribution infrastructure and scale-up manufacturing capabilities to 
commercialize any products beyond zenocutuzumab, for which we may obtain regulatory approvals;
•
maintain, expand and protect our intellectual property portfolio;
•
secure, maintain and/or obtain freedom to operate for our technologies and products;
•
add clinical, scientific, operational, financial, information technology and management information systems and personnel, 
including personnel to support our product development and potential future commercialization efforts and to support our 
operation as a public company; and
•
experience any delays or encounter any issues with any of the above, including but not limited to failed studies, complex 
results, manufacturing, potential commercialization challenges, safety issues or other regulatory challenges.

48
We have financed our operations primarily through public offerings and private placements of our common shares and our 
collaboration and license agreement with Incyte, Eli Lilly, Gilead and Biohaven. We have devoted a significant portion of our 
financial resources and efforts to developing our full-length bispecific antibody therapeutics, which we refer to as Biclonics®, our 
technology platforms, identifying potential antibody candidates, conducting pre-clinical studies of a variety of candidates, and 
conducting our clinical trials of zenocutuzumab, petosemtamab, and MCLA-129. 
To become and remain profitable, we must succeed in developing and eventually commercializing products beyond zenocutuzumab in 
NRG1+ pancreatic adenocarcinoma and NSCLC, that generate significant revenue. This will require us to be successful in a range of 
challenging activities, including completing pre-clinical testing and clinical trials of our antibody candidates, discovering and 
developing additional antibody candidates, obtaining regulatory approval for any antibody candidates that successfully complete 
clinical trials, establishing manufacturing and marketing capabilities and ultimately selling any products for which we may obtain 
regulatory approval. We are only in the preliminary stages of many of these activities. We may never succeed in these activities and, 
even if we do, may never generate revenue that is significant enough to achieve profitability.
Because of the numerous risks and uncertainties associated with pharmaceutical product and biological development, we are unable to 
accurately predict the timing or amount of increased expenses or when, or if, we will be able to achieve profitability. If we are 
required by the U.S. Food and Drug Administration (FDA), or the European Medicines Agency (EMA), or other regulatory authorities 
to perform studies in addition to those we currently anticipate, or if there are any delays in completing our clinical trials or the 
development of any of our antibody candidates, our expenses could increase and commercial revenue could be further delayed.
Even if we do generate product royalties or product sales, we may never achieve or sustain profitability on a quarterly or annual basis. 
Our failure to sustain profitability could depress the market price of our common shares and could impair our ability to raise capital, 
expand our business, diversify our product offerings or continue our operations. 
We will need additional funding in order to complete development of our antibody candidates and commercialize our products, if 
approved. 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 to continue to incur significant expenses in connection with our ongoing activities, particularly as we conduct our ongoing 
clinical trials of petosemtamab, and MCLA-129, potential new development activities for zenocutuzumab, and continue to research, 
develop and conduct pre-clinical studies of our other antibody candidates. In addition, beyond zenocutuzumab, which we have 
licensed to PTx to commercialize in the United States, in the field of NRG1+ cancer, if we obtain regulatory approval for any of our 
other antibody candidates, we expect to incur significant commercialization expenses related to product manufacturing, marketing, 
sales and distribution. Furthermore, we continue to incur additional costs associated with operating as a public company. Accordingly, 
we will need to obtain substantial additional funding in connection with our continuing operations. If we are unable to raise capital 
when needed or on attractive terms, we could be forced to delay, reduce or eliminate our research and development programs or any 
future commercialization efforts. For example, the trading prices for our and other biopharmaceutical companies’ shares have been 
highly volatile as a result of the United States political environment, disruptions and extreme volatility in the global economy, 
including rising inflation and interest rates, declines in economic growth, the ongoing conflicts in Europe and the Middle East. As a 
result, we may face difficulties raising capital through sales of our common shares and any such sales may be on unfavorable terms.
Based on our current operating plan, we expect that our existing cash, cash equivalents and investments as of December 31, 2024 will 
be sufficient to fund our operations into 2028. We have based this estimate on assumptions that may prove to be wrong, and we could 
use our capital resources sooner than we currently expect. We maintain the majority of our cash and cash equivalents in accounts with 
major U.S. and multi-national financial institutions, and our deposits at these institutions exceed insured limits. Market conditions can 
impact the viability of these institutions. In the event of failure of any of the financial institutions where we maintain our cash and cash 
equivalents, there can be no assurance that we would be able to access uninsured funds in a timely manner or at all. Any inability to 
access or delay in accessing these funds could adversely affect our business and financial position. Our future capital requirements 
will depend on many factors, including:
•
the cost, progress and results of our ongoing clinical trials of petosemtamab and  MCLA-129 and potential additional 
development activities for zenocutuzumab; 
•
the success of our collaborations with Incyte, Lilly, Gilead and Biohaven to develop antibody candidates;
•
the cost of manufacturing clinical supplies of our multispecific antibody candidates;
•
the scope, progress, results and costs of pre-clinical development, laboratory testing and clinical trials for our other 
antibody candidates;

49
•
the costs, timing and outcome of regulatory review of any of our antibody candidates;
•
the costs and timing of potential future commercialization activities, including manufacturing, marketing, sales and 
distribution, for any of our antibody candidates to the extent any receive marketing approval;
•
the costs and timing of preparing, filing and prosecuting patent applications, maintaining and enforcing our intellectual 
property rights and defending any intellectual property-related claims, including any potential future claims by third 
parties that we are alleged to be infringing upon their intellectual property rights;
•
the costs and timing of securing, maintaining and/or obtaining freedom to operate for our technologies and products;
•
the revenue, if any, received from commercial sales of our antibody candidates to the extent any receive marketing 
approval;
•
the extent to which we can realize planned cost efficiencies;
•
the effect of competing technological and market developments; and
•
the extent to which we acquire or invest in businesses, products and technologies, including our existing collaborations 
and any other future licensing or collaboration arrangements for any of our antibody candidates.

50
We depend heavily on the success of our antibody candidates, and we cannot give any assurance that any of our antibody 
candidates will receive regulatory approval, beyond BIZENGRI®, which is necessary before they can be commercialized. If we, 
any of our collaborators, or any other strategic partners we may enter into collaboration agreements with for the development and 
commercialization of our antibody candidates, are unable to commercialize our antibody candidates, or experience significant 
delays in doing so, our business, financial condition and results of operations will be materially adversely affected.
We have invested a significant portion of our efforts and financial resources in the development of bispecific antibody candidates 
using our Biclonics® technology platform and in development of multi-specific antibody candidates using our Triclonics® technology 
platform. Our ability to generate royalty and product revenues, if ever, will depend heavily on the successful development and 
eventual commercialization of these antibody candidates, which may never occur. We currently have generated no revenues from 
sales of any products, and we may never be able to develop or commercialize a marketable product, nor may our commercial licensee 
PTx for the marketing of BIZENGRI® for NRG1+ pancreatic adenocarcinoma and NSCLC. BIZENGRI® was approved under 
accelerated approval based on overall response rate (ORR) and duration of response (DOR) and continued approval for these 
indications may be contingent upon verification and description of clinical benefit in a confirmatory trial(s). Beyond the indications 
approved under the BIZENGRI® label, each of our bispecific antibody candidates and pre-clinical antibody candidates will require 
additional clinical development, management of clinical, pre-clinical and manufacturing activities, regulatory approval in multiple 
jurisdictions, obtaining manufacturing supply, including commercial manufacturing supply, building of a commercial organization, 
substantial investment and significant marketing efforts before we generate any revenues from product sales. We are not permitted to 
market or promote any of our antibody candidates before we receive regulatory approval from the FDA or comparable foreign 
regulatory authorities, and we may never receive such regulatory approval for any of our antibody candidates. The success of our 
antibody candidates will depend on several factors, including the following:
•
for antibody candidates which we may license to others, such as to our collaborators, the successful efforts of those 
parties in completing clinical trials of, receipt of regulatory approval for and commercialization of such antibody 
candidates;
•
for the antibody candidates to which we retain rights, completion of pre-clinical studies and clinical trials of, receipt of 
marketing approvals for, establishment of commercial manufacturing supplies of and successful commercialization of 
such antibody candidates; and
•
for all of our antibody candidates, if approved, acceptance of our antibody candidates by patients, the medical 
community and third-party payors, effectively competing with other therapies, a continued acceptable safety profile 
following approval and qualifying for, maintaining, enforcing and defending our intellectual property rights and claims.
If we or our collaborators, as applicable, do not achieve one or more of these factors in a timely manner or at all, we could experience 
significant delays or an inability to successfully commercialize our antibody candidates, which would materially adversely affect our 
business, financial condition and results of operations.
Beyond BIZENGRI®'s accelerated approval by the US FDA, we cannot be certain that any of our antibody candidates will be 
successful in clinical trials or receive regulatory approval. Further, our antibody candidates may not receive regulatory approval even 
if they are successful in clinical trials. If we do not receive regulatory approvals for our antibody candidates, we may not be able to 
continue our operations. Even if we successfully obtain regulatory approvals to market one or more of our antibody candidates, our 
revenues will be dependent, in part, upon the size of the markets in the territories for which we gain regulatory approval and have 
commercial rights. If the markets for patient subsets that we are targeting are not as significant as we estimate, we may not generate 
significant revenues from sales of such products, if approved.
We plan to seek regulatory approval to commercialize our antibody candidates both in the United States and the European Union 
(EU), and potentially in additional foreign countries. While the scope of regulatory approval is similar in other countries, to obtain 
separate regulatory approval in many other countries we must comply with the numerous and varying regulatory requirements of such 
countries regarding safety and efficacy and governing, among other things, clinical trials and commercial sales, pricing and 
distribution of our antibody candidates, and we cannot predict success in these jurisdictions.

51
The Biclonics® technology platform and Triclonics® technology platform are unproven, novel approaches to the production of 
biologics for therapeutic intervention.
Beyond BIZENGRI®, we have not received regulatory approval for a therapeutic based on a full-length human bispecific or 
trispecific IgG approach. We cannot be certain that our approach will lead to the development of approvable or marketable products. 
In addition, our Biclonics® and Triclonics® may have different effectiveness rates in various indications and in different geographical 
areas. 
Our Biclonics® and Triclonics® technology platforms rely on third parties for biological materials. Some biological materials have 
not always met our expectations or requirements, and any disruption in the supply of these biological materials could materially 
adversely affect our business. Although we have control processes, auditing and screening procedures, biological materials are 
susceptible to damage and contamination and may contain active pathogens. Further, assays used to test the identity and potency of 
zenocutuzumab and our antibody candidates are susceptible to deviations or inaccuracy, which can impact the testing and release of 
these products for commercial or clinical use. Similarly, improper filling or storage of these materials, by us or any third-party 
suppliers, may require us to destroy some of our biological raw materials or antibody candidates.
Failure to successfully validate, develop and obtain regulatory approval or certification for companion diagnostics could harm our 
development strategy.
We may seek to identify patient subsets within a disease category that may derive selective and meaningful benefit from the antibody 
candidates we are developing. Through collaborations or license agreements, companion diagnostics may help us to more accurately 
identify patients within a particular subset, both during our clinical trials and in connection with the commercialization of our antibody 
candidates, if approved. Companion diagnostics are subject to regulation by the FDA, and comparable foreign regulatory authorities as 
medical devices and typically require separate regulatory approval (or clearance, or certification) prior to commercialization. The 
development of companion diagnostics in collaboration with or via license agreements with third parties, may make us potentially 
dependent on the scientific insights and sustained cooperation and effort of any third-party collaborators in developing and obtaining 
approval (or clearance, or certification) for companion diagnostics. Difficulties in developing and obtaining approval or certification 
for any companion diagnostics may be encountered, including as it concerns issues relating to selectivity/specificity, analytical 
validation, reproducibility or clinical validation. Any delay or failure to develop or obtain regulatory approval (or clearance, or 
certification) of companion diagnostics could delay or prevent approval of our antibody candidates. In addition, production difficulties 
may be encountered that could constrain the supply of the companion diagnostics, and difficulties may arise in gaining acceptance of 
the use of the companion diagnostics in the clinical community. If such companion diagnostics fail to gain market acceptance, it could 
have an adverse effect on our ability to derive revenues from sales of our products. In addition, the diagnostic company with whom we 
contract may decide to discontinue selling or manufacturing the companion diagnostic that we anticipate using in connection with 
development and commercialization of our antibody candidates or our relationship with such diagnostic company may otherwise 
terminate. We may not be able to enter into arrangements with another diagnostic company to obtain supplies of an alternative 
companion diagnostic test for use in connection with the development and commercialization of our antibody candidates or do so on 
commercially reasonable terms, which could adversely affect and/or delay the development or commercialization of our antibody 
candidates.
Our limited operating history may make it difficult for you to evaluate the success of our business to date and to assess our future 
viability.
Since our inception in 2003, we have devoted a significant portion of our resources to developing zenocutuzumab, petosemtamab, and 
MCLA-129 and our other antibody candidates, building our intellectual property portfolio, developing our clinical manufacturing 
supply chain, generating and enhancing our Biclonics® and Triclonics® technology platforms, planning our business, raising capital 
and providing general and administrative support for these operations. While we have completed certain of the clinical trials for 
zenocutuzumab, we have limited experience and have not completed clinical trials for petosemtamab and MCLA-129. We have not 
yet demonstrated our ability to successfully to manufacture a commercial scale product or have only recently arranged for a third party 
to do so on our behalf and we have not demonstrated our ability to conduct sales and marketing activities necessary for successful 
product commercialization. Additionally, we expect our financial condition and operating results to continue to fluctuate significantly 
from quarter to quarter and year to year due to a variety of factors, many of which are beyond our control. Consequently, any 
predictions you make about our future success or viability may not be as accurate as they could be if we had a longer operating 
history.

52
Raising additional capital may cause dilution to our holders, restrict our operations or require us to relinquish rights to our 
technologies or antibody candidates.
Until such time, if ever, as we can generate substantial product revenues, we expect to finance our cash needs through equity or debt 
financings and upfront and milestone payments, if any, received under our existing collaborations and any other future licenses or 
collaborations, together with our existing cash and cash equivalents. In order to accomplish our business objectives and further 
develop our product pipeline, we will, however, need to seek additional funds. If we raise additional capital through the sale of equity 
or convertible debt securities, our existing shareholders’ ownership interests will be diluted, and the terms of these securities may 
include liquidation or other preferences that adversely affect our existing shareholders’ rights as holders of our common shares. In 
addition, the possibility of such issuance may cause the market price of our common shares to decline. Debt financing, if available, 
may result in increased fixed payment obligations and involve agreements that include covenants limiting or restricting our ability to 
take specific actions, such as incurring additional debt, making capital expenditures, declaring dividends, or acquiring, selling or 
licensing intellectual property rights, which could adversely impact our ability to conduct our business.
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 intellectual property, technologies, future revenue streams or antibody 
candidates or grant licenses on terms that may not be favorable to us. We could also be required to seek funds through arrangements 
with collaborators or others at an earlier stage than otherwise would be desirable. Any of these occurrences may have a material 
adverse effect on our business, operating results and prospects.
Any additional fundraising efforts may divert our management from their day-to-day activities, which may adversely affect our ability 
to develop and commercialize our antibody candidates. In addition, we cannot guarantee that future financing will be available in 
sufficient amounts or on terms acceptable to us, if at all. For example, the trading prices for our and other biopharmaceutical 
companies’ shares have been highly volatile as a result of the United States political environment, disruptions and extreme volatility in 
the global economy, including rising inflation and interest rates, declines in economic growth, global instability, including the ongoing 
conflict in Europe and the Middle East. As a result, we may face difficulties raising capital through sales of our common shares and 
any such sales may be on unfavorable terms. If we are unable to obtain funding on a timely basis, we may be required to significantly 
curtail, delay or discontinue one or more of our research or development programs or the commercialization of any of our antibody 
candidates, if approved, or be unable to expand our operations or otherwise capitalize on our business opportunities, as desired, which 
could materially affect our business, financial condition and results of operations.
Our business may become subject to economic, political, regulatory and other risks associated with international operations.
As a company based in the Netherlands, our business is subject to risks associated with conducting business internationally. Many of 
our suppliers and collaborative and clinical trial relationships are located outside the United States. Accordingly, our future results 
could be harmed by a variety of factors, including:
•
economic weakness, including inflation, or political instability, in particular, in non-U.S. economies and markets;
•
differing regulatory requirements for drug approvals in non-U.S. countries;
•
differing jurisdictions could present different issues for securing, maintaining and/or obtaining freedom to operate in 
such jurisdictions;
•
potentially reduced protection for intellectual property rights;
•
difficulties in compliance with non-U.S. laws and regulations;
•
changes in non-U.S. regulations and customs, tariffs and trade barriers;
•
changes in non-U.S. currency exchange rates of the euro and currency controls;
•
changes in a specific country’s or region’s political or economic environment;
•
trade protection measures, import or export licensing requirements or other restrictive actions by U.S. or non-U.S. 
governments;
•
differing reimbursement regimes and price controls in certain non-U.S. markets;
•
negative consequences from changes in tax laws;

53
•
compliance with tax, employment, immigration and labor laws for employees living or traveling abroad;
•
compliance with international privacy regulations, including the European Union General Data Protection Regulation 
(GDPR) and United Kingdom General Data Protection Regulation (UK GDPR);
•
negative consequences from the United Kingdom’s withdrawal from the EU, and its potential impact on supply-chain 
and our personnel;
•
workforce uncertainty in countries where labor unrest is more common than in the United States;
•
difficulties associated with staffing and managing international operations, including differing labor relations;
•
production shortages resulting from any events affecting raw material supply or manufacturing capabilities abroad; and
•
business interruptions resulting from geo-political actions, including war, riots and terrorism, as well as the ongoing 
conflict in Europe and Middle East, or natural disasters including earthquakes, typhoons, floods, fires, epidemics or 
public health emergencies and U.S. or non-U.S. governmental actions or restrictions related thereto.
Exchange rate fluctuations or abandonment of the euro currency may materially affect our results of operations and financial 
condition.
Due to the international scope of our operations, fluctuations in exchange rates, particularly between the euro and the U.S. dollar, may 
adversely affect us. Although we are based in the Netherlands, we source research and development, manufacturing, consulting and 
other services from several countries. Further, potential future revenue may be derived from abroad, particularly from the United 
States. Additionally, our funding has mainly come from investors and collaborators mainly in the United States. As a result, our 
business and share price may be affected by fluctuations in foreign exchange rates between the euro and these other currencies, which 
may also have a significant impact on our reported results of operations and cash flows from period to period. Currently, we do not 
have any exchange rate hedging arrangements in place.
In addition, the possible abandonment of the euro by one or more members of the EU could materially affect our business in the 
future. Despite measures taken by the EU to provide funding to certain EU member states in financial difficulties and by a number of 
European countries to stabilize their economies and reduce their debt burdens, it is possible that the euro could be abandoned in the 
future as a currency by countries that have adopted its use. This could lead to the re-introduction of individual currencies in one or 
more EU member states, or in more extreme circumstances, the dissolution of the EU. The effects on our business of a potential 
dissolution of the EU, the exit of one or more EU member states from the EU or the abandonment of the euro as a currency, are 
impossible to predict with certainty, and any such events could have a material adverse effect on our business, financial condition and 
results of operations.
Risks from improper conduct by our employees, agents, contractors, or collaborators could adversely affect our reputation, 
business, prospects, operating results, and financial condition.
We cannot ensure that our compliance controls, policies, and procedures will in every instance protect us from acts committed by our 
employees, agents, contractors, or collaborators that would violate the laws or regulations of the jurisdictions in which we operate, 
including, without limitation, health care, employment, foreign corrupt practices, trade restrictions and sanctions, environmental, 
import and export requirements, competition, patient privacy and other privacy laws and regulations. Such improper actions could 
subject us to civil or criminal investigations, and monetary and injunctive penalties, and could adversely impact our ability to conduct 
business, operating results, and reputation.
We are subject to a number of anti-corruption laws, including the Foreign Corrupt Practices Act (FCPA) in the United States, the 
Bribery Act in the United Kingdom and the anti-corruption provisions of the Dutch Criminal Code in the Netherlands. Our failure to 
comply with anti-corruption laws applicable to us could result in penalties, which could harm our reputation and harm our business, 
financial condition, results of operations, cash flows or prospects. The FCPA generally prohibits companies and their intermediaries 
from making improper payments to foreign officials for the purpose of improperly or corruptly obtaining or keeping business, 
obtaining preferential treatment and/or other undue benefits or advantages. The FCPA also requires public companies to maintain 
accurate books and records and devise a system of sufficient internal accounting controls. We regularly review and update our policies 
and procedures and internal controls designed to provide reasonable assurance that we, our employees, distributors and other 
intermediaries comply with the anti-corruption laws to which we are subject. However, there are inherent limitations to the 
effectiveness of any policies, procedures and internal controls, including the possibility of human error and the circumvention or 

54
overriding of the policies, procedures and internal controls. There can be no assurance that such policies or procedures or internal 
controls will work effectively at all times or protect us against liability under these or other laws for actions taken by our employees, 
distributors and other intermediaries with respect to our business.
The Securities and Exchange Commission (SEC) and Department of Justice continue to view FCPA enforcement activities as a high 
priority. There is no certainty that all of our employees, agents, contractors, or collaborators, or those of our affiliates, will comply 
with all applicable laws and regulations, particularly given the high level of complexity of these laws. Violations of these laws and 
regulations could result in fines, criminal sanctions against us, our officers, or our employees, requirements to obtain export licenses, 
cessation of business activities in sanctioned countries, implementation of compliance programs, and prohibitions on the conduct of 
our business. Any such violations could materially damage our reputation, our brand, our international operations, our ability to attract 
and retain employees, and our business, prospects, operating results, and financial condition.
Risks Related to the Development and Clinical Testing of Our Antibody Candidates
All of our antibody candidates are in pre-clinical or clinical development. Clinical drug development is a lengthy and expensive 
process with uncertain timelines and uncertain outcomes. If clinical trials of our antibody candidates, particularly petosemtamab 
and MCLA-129, are prolonged or delayed, we or any collaborators may be unable to obtain required regulatory approvals, and 
therefore be unable to commercialize our antibody candidates on a timely basis or at all.
To obtain the requisite regulatory approvals to market and sell any of our antibody candidates, we or any collaborator for such 
candidates must demonstrate through extensive pre-clinical studies and clinical trials that such candidates are safe, pure and potent in 
humans. Clinical testing is expensive and can take many years to complete, and its outcome is inherently uncertain. Failure can occur 
at any time during the clinical trial process. The results of pre-clinical studies and early-stage clinical trials of our antibody candidates 
may not be predictive of the results of later-stage clinical trials. Antibody candidates in later stages of clinical trials may fail to show 
the desired safety and efficacy traits despite having progressed through pre-clinical studies and initial clinical trials. A number of 
companies in the biopharmaceutical industry have suffered significant setbacks in advanced clinical trials due to lack of efficacy or 
adverse safety profiles, notwithstanding promising results in earlier trials. Our future clinical trial results may not be successful.
To date, we have only completed a clinical trial required for the accelerated approval of BIZENGRI® in the current indications. 
Although we are conducting ongoing clinical trials for petosemtamab, and MCLA-129, considering potential further development for 
zenocutuzumab and exploring pre-clinical studies for other antibody candidates, we may experience delays in our ongoing clinical 
trials and we do not know whether planned clinical trials will begin on time, need to be redesigned, enroll patients on time or be 
completed on schedule, if at all. Clinical trials can be delayed, suspended, or terminated for a variety of reasons, including the 
following: 
•
failure to maintain accelerated approval for zenocutuzumab due to an inability to verify clinical benefit in confirmatory 
trials, and/or post-marketing commitments or requirements;
•
delays in or failure to reach agreement on acceptable terms with prospective CROs and clinical trial sites, the terms of 
which can be subject to extensive negotiation and may vary significantly among different CROs and trial sites;
•
delays in or failure to recruit suitable patients to participate in a trial;
•
delays in or failure to establish the appropriate dose and schedule for antibody candidates in clinical trials;
•
the difficulty in identifying the sub-populations that we are trying to treat in a particular trial, which may delay 
enrollment and reduce the power of a clinical trial to detect statistically significant results;
•
lower than anticipated retention rates of patients in clinical trials;
•
failure to have patients complete a trial or return for post-treatment follow-up;
•
clinical sites deviating from trial protocol or dropping out of a trial;
•
investigator-sponsored studies of our product candidates, including expanded or early access protocols, may identify 
safety or efficacy concerns associated with our antibody candidates, or otherwise negatively affect patient enrollment in 
our ongoing and planned clinical trials;
•
delays in, inability or failure to add new clinical trial sites;

55
•
safety or tolerability concerns could cause us or our collaborators or regulatory authorities, as applicable, to pause, 
suspend or terminate a trial if we or our collaborators or regulatory authorities, find that the participants are being 
exposed to unacceptable health risks or during evaluation of safety signals;
•
failure to observe a meaningful clinical benefit;
•
delays in or failure to obtain regulatory approval or authorizations to commence a trial;
•
delays in or failure to obtain institutional review board (IRB) or ethics committee approval at each site;
•
our third-party research contractors failing to comply with regulatory requirements or applicable law, or to meet their 
contractual obligations to us in a timely manner, or at all;
•
changes in regulatory requirements, policies and guidelines;
•
manufacturing sufficient quantities of our antibody candidate for use in clinical trials or our commercial product to meet 
market demand;
•
the quality or stability of our commercial product and/or an antibody candidate falling below acceptable standards;
•
changes in the treatment landscape for our target indications that may make our antibody candidates no longer relevant;
•
third party actions claiming infringement by our antibody candidates in clinical trials outside of the United States and 
obtaining injunctions interfering with our progress; and
•
business interruptions resulting from geo-political actions, including war and terrorism, or natural disasters including 
earthquakes, typhoons, floods and fires, epidemics or public health emergencies and U.S. or non-U.S. governmental 
actions or restrictions related thereto.
We could encounter delays if a clinical trial is paused, suspended or terminated by us, by the IRBs or ethics committees of the 
institutions in which such trials are being conducted, by the Data Review Committee or Data Safety Monitoring Board for such trial or 
by the FDA, the competent authorities of the European Economic Area (EEA) countries (the 27 EU member states plus Iceland, 
Liechtenstein and Norway) and the UK, or other regulatory authorities. Such authorities may impose such a suspension or termination 
due to a number of factors, including failure to conduct the clinical trial in accordance with regulatory requirements or our clinical 
protocols, inspection of the clinical trial operations or trial site by the FDA, EEA competent authorities or other regulatory authorities 
resulting in the imposition of a clinical hold, unforeseen safety issues or adverse side effects, failure to demonstrate a benefit from 
using a drug, changes in governmental regulations or administrative actions or lack of adequate funding to continue the clinical trial. If 
we experience delays in the completion of, or termination of, any clinical trial of our antibody candidates, the commercial prospects of 
our antibody candidates will be harmed, and our ability to generate product revenues from any of these antibody candidates, if 
approved, will be delayed. In addition, any delays in completing our clinical trials will increase our costs, slow down our antibody 
candidate development and approval process and jeopardize our ability to commence product sales and generate revenues. Significant 
clinical trial delays could also allow our competitors to bring products to market before we do or shorten any periods during which we 
have the exclusive right to commercialize our antibody candidates and impair our ability to commercialize our antibody candidates, if 
approved, and may harm our business and results of operations.
Any of these occurrences may harm our business, financial condition and prospects significantly. In addition, many of the factors that 
cause, or lead to, a delay in the commencement or completion of clinical trials may also ultimately lead to the denial of regulatory 
approval of our antibody candidates.
Clinical trials must be conducted in accordance with the FDA, EEA countries, and other applicable regulatory authorities’ legal 
requirements, other regulations or guidelines, and are subject to oversight by these governmental agencies and ethics committees or 
IRBs at the medical institutions where the clinical trials are conducted. In addition, clinical trials must be conducted with supplies of 
our antibody candidates produced under current good manufacturing practice (cGMP), or similar foreign requirements and other 
regulations. Furthermore, we rely on CROs and clinical trial sites to ensure the proper and timely conduct of our clinical trials and 
while we have agreements governing their committed activities, we have limited influence over their actual performance. We depend 
on our collaborators and on medical institutions and CROs to conduct our clinical trials in compliance with good clinical practice 
(GCP) requirements. To the extent our collaborators or the CROs fail to enroll participants for our clinical trials, fail to conduct the 
study to GCP standards or are delayed for a significant time in the execution of trials, including achieving full enrollment, we may be 
affected by increased costs, program delays or both, which may harm our business. In addition, clinical trials that are conducted in 

56
countries outside the EEA and the United States may subject us to further delays and expenses as a result of increased shipment costs, 
additional regulatory requirements and the engagement of non-EEA and non-U.S. CROs, as well as expose us to risks associated with 
clinical investigators who are unknown to the FDA or the EEA competent authorities, and may use different standards of diagnosis, 
screening and medical care.
In addition, the FDA’s and other regulatory authorities’ policies with respect to clinical trials may change and additional government 
regulations may be enacted. For instance, the regulatory landscape related to clinical trials in the EU recently evolved. The EU 
Clinical Trials Regulation (CTR) which was adopted in April 2014 and repeals the EU Clinical Trials Directive, became applicable on 
January 31, 2022. While the EU Clinical Trials Directive required a separate clinical trial application (CTA) to be submitted in each 
member state in which the clinical trial takes place, to both the competent national health authority and an independent ethics 
committee, the CTR introduces a centralized process and only requires the submission of a single application for multi-center trials. 
The CTR allows sponsors to make a single submission to both the competent authority and an ethics committee in each member state, 
leading to a single decision per member state. The assessment procedure of the CTA has been harmonized as well, including a joint 
assessment by all member states concerned, and a separate assessment by each member state with respect to specific requirements 
related to its own territory, including ethics rules. Each member state’s decision is communicated to the sponsor via the centralized EU 
portal. Once the CTA is approved, clinical study development may proceed. The CTR transition period ended on January 31, 2025, 
and all clinical trials (and related applications) are now fully subject to the provisions of the CTR. Compliance with the CTR 
requirements by us, our collaborators and third-party service providers, such as CROs, may impact our developments plans.
It is currently unclear to what extent the UK will seek to align its regulations with the EU. The UK regulatory framework in relation to 
clinical trials is derived from the now-repealed EU Clinical Trials Directive (as implemented into UK law, through the Medicines for 
Human Use (Clinical Trials) Regulations 2004, as amended). 
The extent to which the regulation of clinical trials in the UK will mirror the (EU) CTR in the long term is not yet certain, however, on 
December 12, 2024, the UK government introduced a legislative proposal - the Medicines for Human Use (Clinical Trials) 
Amendment Regulations 2024 - that, if implemented, will replace the current regulatory framework for clinical trials in the UK. The 
UK government has provided the legislative proposal to the UK Parliament for its review and approval. Once the legislative proposal 
is approved (with or without amendment), it will be adopted into UK law which is expected in early 2026. A decision by the UK not 
to closely align its regulations with the new approach that has been adopted in the EU may have an effect on the cost of conducting 
clinical trials in the UK as opposed to other countries. 
If we are slow or unable to adapt to changes in existing requirements or the adoption of new requirements or policies governing 
clinical trials, our development plans may be impacted.
Interim, preliminary, and “top-line” data from our clinical trials that we announce or publish from time to time may change as 
more patient data become available and are subject to audit and verification procedures that could result in material changes in 
the final data.
From time to time, we may publish interim, preliminary or “top-line” data from our clinical trials. Interim data from clinical trials that 
we may complete are subject to the risk that one or more of the clinical outcomes may materially change as patient enrollment 
continues and more patient data become available. Preliminary and top-line data also remain subject to audit and verification 
procedures that may result in the final data being materially different from the preliminary data previously published. In addition, we 
may decide to report interim or preliminary analyses of only certain endpoints (e.g., primary subject to investigator review) rather than 
all endpoints (e.g., including secondary subject to central review). As a result, interim, preliminary and top-line data should be viewed 
with caution until the final data are available. 
Furthermore, the information we choose to publicly disclose regarding a particular study or clinical trial is based on more extensive 
information, and others may not agree with what we determine is the material or otherwise appropriate information to disclose. Any 
information we determine not to disclose may ultimately be deemed significant with respect to future decisions, conclusions, views, 
activities, or otherwise regarding a particular antibody candidate or our business. Others, including regulatory agencies, may not 
accept or agree with our assumptions, estimates, calculations, conclusions, or analyses or may interpret or weigh the importance of 
data differently, which could impact the value of particular programs, the approvability or commercialization of the particular 
antibody candidates, and our business in general. As a result, interim, preliminary or top-line data and analyses should be viewed with 
caution. Adverse differences between preliminary, top-line or interim data and final data or changes in what is material information 
regarding the results from a particular study or clinical trial could significantly harm our clinical development and business prospects 
and cause volatility in the price of our common shares. If the interim, top-line, or preliminary data that we report differ from actual or 
final results, or if others, including regulatory authorities, disagree with the conclusions reached, our ability to obtain approval for, and 

57
commercialize, our product candidates may be harmed, which could harm our business, operating results, prospects or financial 
condition.
Our antibody candidates may have serious adverse, undesirable or unacceptable side effects which may delay or prevent marketing 
approval. If such side effects are identified during the development of our antibody candidates or following approval, if any, we 
may need to abandon our development of such antibody candidates, the commercial profile of any approved label may be limited, 
or we may be subject to other significant negative consequences following marketing approval, if any.
Undesirable side effects that may be caused by our antibody candidates, whether alone or in combination with other drugs, could 
cause us or regulatory authorities to interrupt, delay or halt clinical trials and could result in a more restrictive label or the delay or 
denial of regulatory approval by the FDA, or other comparable foreign authorities. 
In February 2015, we commenced a Phase 1/2 clinical trial in Europe of our most advanced antibody candidate, zenocutuzumab, for 
the treatment of various solid tumors, which was amended to treat patients having solid tumors harboring a NRG1 gene fusion. 
Additionally, in January 2018 we commenced a Phase 2 clinical trial in Europe and the United States exploring zenocutuzumab, in 
combination with other agents, in patients with metastatic breast cancer. Patients treated with zenocutuzumab have experienced 
adverse reactions that may be related to the treatment with a safety update provided for zenocutuzumab in October 2023, at the 
European Society for Medical Oncology (ESMO) Congress 2023, with a safety cut-off date of July 31, 2023. 
Patients treated with petosemtamab have experienced adverse reactions that may be treatment related. In May 2018 we commenced a 
Phase 1/2 clinical trial of our bispecific antibody petosemtamab in patients with solid tumors and on January 15, 2021, at ASCO GI, 
with a safety data cutoff date of September 7, 2020, where safety events were reported for patients treated with petosemtamab as a 
single agent across 11 dose levels (5 to 1500mg), and at the AACR-NCI-EORTC Virtual International Conference on Molecular 
Targets and Cancer Therapeutics, on October 7-10, 2021, with a data cutoff date of August 9, 2021. A safety update was provided for 
petosemtamab in December 2024 at the ESMO Asia Congress 2024, with a safety data cutoff date of July 5, 2024 for the treatment of 
82 pt receiving petosemtamab 1500mg Q2W in patients with 2L+ HNSCC. A safety update was further provided in June 2024 at 
ASCO, with a safety data cutoff date of March 6, 2024 for the treatment of 42 pts receiving petosemtamab 1500mg Q2W in patients 
with 1L r/m PD-L1+ HNSCC in combination with pembrolizumab 400 mg IV Q6W.  In May 2021, we commenced a Phase 1/2 
clinical trial in the United States of our bispecific antibody MCLA-129 in patients with advanced NSCLC and other solid tumors. 
Patients treated with MCLA-129 have experienced adverse events, with a safety update provided for MCLA-129 in December 2023 at 
the ESMO Asia Congress 2023 held in Singapore, December 1-3, and an additional update in June 2024 at ASCO with a safety data 
cutoff date of February 16, 2024, for the treatment of 22 pt receiving MCLA-129 1500mg Q2W in patients with MET Exon 14 
Skipping Mutation (METexon14) NSCLC. 
We also engage in combination studies of our antibody candidates in combination with other approved therapies, the combination of 
which may also cause or be correlated with undesirable side effects not observed in our monotherapy trials that may cause us or 
regulatory authorities to interrupt, delay or halt clinical trials and could result in a more restrictive label or the delay or denial of 
regulatory approval by the FDA, the EMA or other comparable foreign authorities. For example, in 2023, we commenced a Phase 1/2 
investigation of petosemtamab in combination with pembrolizumab as a potential front-line therapy for relapsed/metastatic (r/mm) 
HNSCC expressing PD-L1 (combined positive score (CPS) ≥ 1) (PD-L1+). A safety update was further provided in June 2024 at 
ASCO, with a safety data cutoff date of March 6, 2024 for the treatment of 42 pts receiving petosemtamab 1500mg Q2W in patients 
with 1L r/m PD-L1+ HNSCC in combination with pembrolizumab 400 mg IV Q6W. In September 2024, we also initiated a phase 3 
study investigating this combination in patients with 1L r/m PD-L1+ HNSCC to evaluate safety and clinical activity in this population, 
referred to as the LiGeR-HN1 trial. We have observed certain adverse events from patients receiving the combination of 
petosemtamab and pembrolizumab, including infusion related reactions, and asthenia. Common side effects with pembrolizumab 
when used alone include feeling tired, pain, including pain in muscles, rash, diarrhea, fever, cough, decreased appetite, itching, 
shortness of breath, constipation, bones or joints and stomach-area (abdominal) pain, nausea, and low levels of thyroid hormone. We 
provided a safety update for petosemtamab in combination with pembrolizumab in June 2024 at the 2024 American Society of 
Clinical Oncology annual meeting with a data cutoff date of March 6, 2024. In July 2024, we commenced a Phase 2 investigation of 
the combination of petosemtamab with FOLFIRI, in patients with metastatic colorectal cancer (mCRC). We continue to monitor and 
evaluate patients enrolled and have observed certain adverse events from patients receiving the combination. In 2022, we commenced 
a Phase 1/2 investigation of the combination of MCLA-129 with osimertinib, a third generation EGFR TKI, in patients with treatment-
naïve EGFR mutant (m) NSCLC and in patients with EGFRm NSCLC that has progressed on osimertinib. We continue to monitor 
and evaluate patients enrolled and have observed certain adverse events from patients receiving the combination of MCLA-129 in 
combination with osimertinib, including infusion-related reactions, skin toxicity, gastrointestinal events, asthenia, decreased appetite, 
venous thromboembolism (VTE, composite term) and treatment-related interstitial lung disease, with additional details on safety 
reported at the ESMO Asia Congress 2023 held in Singapore, December 1-3. In addition, osimertinib has warnings and precautions 
regarding interstitial lung disease, QT prolongation, cardiomyopathy, keratitis and Stevens-Johnson Syndrome, and toxic epidermal 

58
necrolysis; cutaneous vasculitis, aplastic anemia, embryo-fetal toxicity.  In 2024, we also commenced a Phase 2 investigation of 
MCLA-129 in combination with chemotherapy in 2L+ EGFRm NSCLC, with a cohort receiving MCLA-129 and paclitaxel and 
carboplatin, and another cohort receiving MCLA-129 and docetaxel. We continue to monitor and evaluate patients enrolled and have 
observed certain adverse events from patients receiving this combination. In 2022, we commenced a Phase 1 investigation of MCLA-
145 in combination with pembrolizumab in solid tumors. We continue to monitor and evaluate patients enrolled and have observed 
certain adverse events including fatigue, cough, pyrexia, constipation, decreased appetite, dyspnoea, nausea, dizziness and elevation of 
liver enzymes.
In each of our clinical trials and investigations of our antibody candidates in combination with approved therapies there may still be 
important facts about the safety, efficacy, and risk versus benefit that are not known to us at this time which may negatively impact 
our ability to develop and commercialize our antibody candidates as single agents or in combination with other agents. In this regard,  
we have in the past and may in the future observe serious side effects ranging from grade 1 to grade 5 across our clinical trials, 
including patient death, and we have in the past, and may in the future, institute additional precautionary safety measures such as 
dosing caps and delays, enhanced monitoring for side effects, and modified patient inclusion and exclusion criteria. 
Additional and/or unexpected safety events or our failure to generate additional efficacy data in our clinical trials that support 
registration could significantly impact the value of antibody candidates to our business. Many companies in the pharmaceutical and 
biotechnology industries, including us, have suffered significant setbacks in late-stage clinical trials or combination trials after 
achieving encouraging or positive results in early-stage development. We cannot be certain that we will not face similar setbacks in 
our ongoing or planned clinical trials. If we or our collaborators fail to produce positive results in our ongoing or planned clinical trials 
of our other product candidates, the development timeline and regulatory approval and commercialization prospects for our product 
candidates, and, correspondingly, our business, financial condition, results of operations and growth prospects, would be materially 
adversely affected.
If results of our trials reveal a high and unacceptable severity and prevalence of adverse events or side effects, including those that 
may be new or unexpected, our trials or enrollment could be paused, suspended or terminated and the FDA, EEA competent 
authorities, or comparable foreign regulatory authorities could order us to cease further development of or deny approval of our 
antibody candidates for any or all targeted indications. The drug-related side effects could affect patient recruitment, investigator 
engagement and commitment and perception of the clinical candidate or the ability of enrolled patients to complete the trial or result 
in potential product liability claims. Any of these occurrences may harm our business, financial condition and prospects significantly. 
Additionally, if any of our antibody candidates receives marketing approval and we or others later identify undesirable or 
unacceptable side effects caused by such products, a number of potentially significant negative consequences could result, including:
•
regulatory authorities may withdraw approvals of such products and require us to take our approved product off the 
market;
•
regulatory authorities may require the addition of labeling statements, specific warnings, a contraindication or field alerts 
to physicians and pharmacies;
•
regulatory authorities may require a medication guide outlining the risks of such side effects for distribution to patients, 
or that we implement a risk evaluation and mitigation strategy plan to ensure that the benefits of the product outweigh its 
risks;
•
we may be required to change the dose or the way the product is administered, conduct additional clinical trials or 
change the labeling of the product;
•
we may be subject to limitations on how we may promote the product;
•
sales of the product may decrease significantly;
•
we may be subject to litigation or product liability claims; and
•
our reputation may suffer.
As the approved label for BIZENGRI® includes a boxed warning describing certain risks for embryo-fetal toxicity, and the product 
label also includes warnings regarding infusion-related and anaphylactic reactions, hypersensitivity, interstitial  lung disease, 
pneumonitis, and left ventricular dysfunction, we may encounter these or other similar adverse reactions if we develop zenocutuzumab 
for any other indications 

59
Any of these events could prevent us, our collaborators or our potential future partners from achieving or maintaining market 
acceptance of the affected antibody candidate, if approved, or could substantially increase commercialization costs and expenses, 
which in turn could delay or prevent us from generating significant revenue from the sale of our antibody candidates, if approved.
We depend on enrollment of patients in our clinical trials for our antibody candidates. If we are unable to enroll patients in our 
clinical trials, our research and development efforts and business, financial condition and results of operations could be materially 
adversely affected.
Successful and timely completion of clinical trials will require that we enroll a sufficient number of patient candidates. In the Phase 2 
clinical trial of MCLA-129, we plan to enroll up to 576 adult patients with solid tumors, including in combination with chemotherapy 
in pts with NSCLC, second line resistant to osimertinib or third-line, osimertinib resistant and platinum resistant. In the Phase 1/2 
clinical trial of petosemtamab, we plan to enroll up to 523 adult patients with solid tumors, including as monotherapy in solid tumors, 
in combination with pembrolizumab in PD-L1+ r/m first line head and neck cancer; in 1L mCRC and 2L mCRC in combination with 
standard chemotherapy, and in 3L+ mCRC as monotherapy. We further initiated a randomized phase 3 trial of petosemtamab 
monotherapy, or investigators’ choice of single agent chemotherapy or cetuximab in 2L/3L HNSCC in July 2024 referred to as the 
LiGeR-HN2 trial. We further initiated a randomized phase 3 trial of  petosemtamab in combination with pembrolizumab, a PD-1 
blocking antibody, or pembrolizumab monotherapy, investigating this combination in patients with untreated HNSCC expressing PD-
L1 (CPS > 0) to evaluate safety and clinical activity in this population in September 2024, referred to as the LiGeR-HN1 trial. These 
trials and other trials we conduct may be subject to delays as a result of patient enrollment taking longer than anticipated or patient 
withdrawal. 
Our clinical trials will also compete with other clinical trials for antibody candidates that are in the same therapeutic areas as our 
antibody candidates, and this competition will reduce the number and types of patients available to us, because some patients who 
might have opted to enroll in our trials may instead opt to enroll in a trial being conducted by one of our competitors. Because the 
number of qualified clinical investigators and clinical trial sites is limited, we expect to conduct some of our clinical trials at the same 
clinical trial sites that some of our competitors use, which will reduce the number of patients who are available for our clinical trials at 
such clinical trial sites.
Patient enrollment depends on many factors, including the size and nature of the patient population, eligibility criteria for the trial, the 
proximity of patients to clinical sites, the design of the clinical protocol, the availability of competing clinical trials, the availability of 
new drugs approved for the indication the clinical trial is investigating, and clinicians’ and patients’ perceptions as to the potential 
advantages of the drug being studied in relation to other available therapies. These factors may make it difficult for us to enroll enough 
patients to complete our clinical trials in a timely and cost-effective manner. Delays in the completion of any clinical trial of our 
antibody candidates will increase our costs, slow down our antibody candidate development and approval process, delay or potentially 
jeopardize our ability to commence product sales and generate revenue and harm our reputation and ability to obtain financing. In 
addition, some of the factors that cause, or lead to, a delay in the commencement or completion of clinical trials may also ultimately 
lead to the denial of regulatory approval of our antibody candidates.
We may become exposed to costly and damaging liability claims, either when testing our antibody candidates in the clinic or at the 
commercial stage; and our product liability insurance may not cover all damages from such claims.
We are exposed to potential product liability and professional indemnity risks that are inherent in the research, development, 
manufacturing, marketing and use of pharmaceutical products. Whereas our exclusive commercial license with PTx for the sale in the 
U.S. of BIZENGRI® for the treatment of NRG1+ pancreatic adenocarcinoma and NSCLC requires PTx to indemnify us for any 
product liability claims, we cannot guarantee such indemnity will absolve us of all potential liability. Further, the current and future 
use of antibody candidates by us and our collaborators in clinical trials, and the sale of any approved products in the future, may 
expose us to liability claims. These claims might be made by patients that use the product, healthcare providers, pharmaceutical 
companies, our collaborators or others selling such products. Any claims against us, regardless of their merit, could be difficult and 
costly to defend and could materially adversely affect the market for our antibody candidates or any prospects for commercialization 
of our antibody candidates, if approved.
Although the clinical trial process is designed to identify and assess potential side effects, it is always possible that a drug, even after 
regulatory approval, may exhibit unforeseen side effects. If zenocutuzumab or any of our antibody candidates were to cause adverse 
side effects during clinical trials or after approval, we may be exposed to substantial liabilities. Physicians and patients may not 
comply with any warnings that identify known potential adverse effects and patients who should not use our antibody candidates.
Although we maintain adequate product liability insurance for our antibody candidates, it is possible that our liabilities could exceed 
our insurance coverage or for BIZENGRI®, the limits of indemnity by PTx. We intend to expand our insurance coverage to include 

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the sale of commercial products for future antibody candidates, which we are responsible for obtaining marketing approval and selling 
into the market place. However, we may not be able to maintain insurance coverage at a reasonable cost or obtain insurance coverage 
that will be adequate to satisfy any liability that may arise. If a successful product liability claim or series of claims is brought against 
us for uninsured liabilities or in excess of insured liabilities, our assets may not be sufficient to cover such claims and our business 
operations could be impaired.
Should any of the events described above occur, this could have a material adverse effect on our business, financial condition and 
results of operations.
The regulatory approval processes of the FDA and comparable foreign authorities are lengthy, time consuming and inherently 
unpredictable, and if we are ultimately unable to obtain regulatory approval for our antibody candidates, our business will be 
substantially harmed.
The time required to obtain approval by the FDA and comparable foreign authorities is unpredictable but typically takes many years 
following the commencement of clinical trials and depends upon numerous factors, including the substantial discretion of the 
regulatory authorities. In addition, approval policies, regulations, or the type and amount of clinical data necessary to gain approval 
may change during the course of an antibody candidate’s clinical development and may vary among jurisdictions. We have not 
obtained regulatory approval for any antibody candidate and it is possible that, beyond the accelerated approval obtained for 
BIZENGRI®, none of our existing antibody candidates or any antibody candidates we may seek to develop in the future will obtain 
regulatory approval.
Our antibody candidates could fail to receive regulatory approval for many reasons, including the following:
•
the FDA or comparable foreign regulatory authorities may disagree with the design or implementation of our clinical 
trials;
•
we may be unable to demonstrate to the satisfaction of the FDA or comparable foreign regulatory authorities that an 
antibody candidate is safe, pure, potent and/or effective for its proposed indication;
•
we may be unable to demonstrate that an antibody candidate’s clinical and other benefits outweigh its safety risks;
•
the FDA or comparable foreign regulatory authorities may disagree with our interpretation of data from pre-clinical 
studies or clinical trials;
•
the data collected from clinical trials of our antibody candidates, our data monitoring, oversight of our CROs may not be 
sufficient in amount or quality to support the submission of a BLA or other submission or to obtain regulatory approval 
in the United States, the EU or elsewhere;
•
the FDA or comparable foreign regulatory authorities may fail to approve the manufacturing processes or facilities of 
third-party manufacturers with which we contract for clinical and commercial supplies;
•
the FDA or comparable foreign regulatory authorities and notified bodies may fail to approve (or to clear or to certify) 
the companion diagnostics we contemplate developing with collaborators; and
•
the approval policies or regulations of the FDA or comparable foreign regulatory authorities may significantly change in 
a manner rendering our clinical data insufficient for approval.
•
for instance, the EU pharmaceutical legislation is currently undergoing a complete review process, in the context of the 
Pharmaceutical Strategy for Europe initiative, launched by the European Commission in November 2020. The European 
Commission's proposal for a revision of several legislative instruments related to medicinal products (including 
potentially reducing the duration of regulatory exclusivity and revising the eligibility for expedited pathways) was 
published on April 26, 2023. The proposed revisions remain to be agreed and adopted by the European Parliament and 
European Council. The proposals may be substantially revised before adoption, which is not anticipated before the end 
of 2026. The revisions may, however, have a significant impact on the biopharmaceutical industry and our business in 
the long term.
This lengthy approval process as well as the unpredictability of future clinical trial results may result in our failing to obtain regulatory 
approval to market any of our antibody candidates, which would significantly harm our business, results of operations and prospects. 
The FDA and other regulatory authorities have substantial discretion in the approval process, and determining when or whether 

61
regulatory approval will be obtained for any of our antibody candidates. Even if we believe the data collected from clinical trials of 
our antibody candidates are promising, such data may not be sufficient in quantity or quality to support approval by the FDA or any 
other regulatory authority.
In addition, even if we were to obtain approval, regulatory authorities may approve any of our antibody candidates for fewer or more 
limited indications than we request, may not approve the price we intend to charge for our products, may grant approval contingent on 
the performance of costly post-marketing clinical trials, or may approve an antibody candidate with a label that does not include the 
labeling claims necessary or desirable for the successful commercialization of that antibody candidate. Any of the foregoing scenarios 
could materially harm the commercial prospects for our antibody candidates and have a material adverse effect on our business, 
financial condition and results of operations.
Fast Track designation by the FDA for petosemtamab or potential future Fast Track designation of our other antibody candidates 
may not actually lead to a faster development or regulatory review or approval process.
We have been granted a Fast Track designation for zenocutuzumab for the treatment of patients with metastatic solid tumors harboring 
NRG1 gene fusions that have progressed on standard-of-care therapy and for petosemtamab for the treatment of patients with 
recurrent or metastatic HNSCC whose disease has progressed following treatment with platinum-based chemotherapy and an anti-
programmed cell death protein 1 (anti-PD-1) antibody, and we may seek additional Fast Track designations for zenocutuzumab, 
petosemtamab or for our other antibody candidates. The Fast Track program is intended to expedite or facilitate the process for 
reviewing therapeutic candidates that meet certain criteria. Specifically, investigational biologics are eligible for Fast Track 
designation if they are intended, alone or in combination with one or more drugs or biologics, to treat a serious or life-threatening 
disease or condition and demonstrate the potential to address unmet medical needs for the disease or condition. Fast Track designation 
applies to the combination of the product candidate and the specific indication for which it is being studied. The sponsor of a Fast 
Track candidate has opportunities for more frequent interactions with the applicable FDA review team during product development 
and, once a BLA is submitted, the application may be eligible for priority review. With a Fast Track designation for an antibody 
candidate, the FDA may consider for review sections of the BLA on a rolling basis before the complete application is submitted, if the 
sponsor provides a schedule for the submission of the sections of the BLA, the FDA agrees to accept sections of the BLA and 
determines that the schedule is acceptable, and the sponsor pays any required user fees upon submission of the first section of the 
BLA.
Obtaining a Fast Track designation does not change the standards for product approval but may expedite the development or approval 
process. Even though the FDA has granted such designation to petosemtamab for the treatment of patients with recurrent or metastatic 
HNSCC whose disease has progressed following treatment with platinum-based chemotherapy and an anti-programmed cell death 
protein 1 (anti-PD-1) antibody, this designation may not actually result in faster clinical development or regulatory review or approval. 
Furthermore, such a designation does not increase the likelihood that petosemtamab or any other antibody candidate that may be 
granted Fast Track designation will receive marketing approval in the United States.
Breakthrough Therapy designations (BTD) by the FDA for petosemtamab and any potential future product candidate may not lead 
to a faster development or regulatory review or approval process, and it does not increase the likelihood that the product candidate 
will receive FDA approval.  
We have been granted a Breakthrough Therapy designations for zenocutuzumab  for the treatment of patients with advanced 
unresectable or metastatic NRG1 fusion (NRG1+) pancreatic cancer following progression with prior systemic therapy or who have 
no satisfactory alternative treatment options and for zenocutuzumab for the treatment of patients with advanced unresectable or 
metastatic NRG1+ non-small cell lung cancer (NSCLC), following progression with prior systemic therapy, and we may seek 
additional Breakthrough Therapy designations for zenocutuzumab or for our other antibody candidates, or the comparable 
designations in foreign jurisdictions, where we believe the clinical data support such designations. We have been granted a BTD by 
the FDA for petosemtamab the treatment of patients with recurrent or metastatic (r/m) HNSCC whose disease has progressed 
following treatment with platinum based chemotherapy and an anti-programmed cell death receptor-1 (PD-1) or anti-programmed 
death ligand 1 (PD-L1) antibody. We have also been granted BTD by the FDA for petosemtamab in combination with pembrolizumab 
for the first-line treatment of adult patients with r/m PD-L1 positive HNSCC with CPS ≥ 1
A "Breakthrough Therapy" is defined as a drug or biologic that is intended, alone or in combination with one or more other drugs or 
biologics, to treat a serious or life-threatening disease or condition, and preliminary clinical evidence indicates that the product 
candidate 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 product candidates 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 

62
efficient path for clinical development while minimizing the number of patients placed in ineffective control regimens. Drugs and 
biologics designated as Breakthrough Therapies also receive the same benefits associated with Fast Track designation, including 
eligibility for rolling review of a submitted BLA, if the relevant criteria are met. Designation as a Breakthrough Therapy is within the 
discretion of the FDA. 
Accordingly, even if we believe that one of our product candidates meets the criteria for designation as a Breakthrough Therapy, the 
FDA may disagree and instead determine not to make such designation. In any event, the receipt of a Breakthrough Therapy 
designation for a product candidate may not result in a faster development process, review or approval compared to product candidates 
considered for approval under conventional FDA procedures and it would not assure ultimate approval by the FDA. 
In addition, even if one or more of our product candidates qualify as Breakthrough Therapies and have received such designation, the 
FDA may later decide that the product candidate no longer meets the conditions for qualification and rescind the designation.
We secured approval from the FDA through the use of the accelerated approval pathway for zenocutuzumab and may seek such 
use of the accelerated approval pathway for our other antibody candidates. If we are unable to obtain such approvals in the future, 
we may be required to conduct additional pre-clinical studies or clinical trials beyond those that we contemplate, which could 
increase the expense of obtaining, and delay the receipt of, necessary regulatory approvals. Even for the accelerated approval 
received from the FDA for BIZENGRI®, if our confirmatory trials do not verify clinical benefit, or if we or our licensee PTx does 
not comply with rigorous post-marketing requirements, the FDA may seek to withdraw any accelerated approval we have obtained. 
We have obtained accelerated approval for BIZENGRI® for the treatment of adults with either advanced, unresectable or metastatic 
NSCLC or pancreatic adenocarcinoma that harbors an NRG1 gene fusion, who have disease progression on or after prior systemic 
therapy and may in the future seek accelerated approval for other clinical candidates. Under the accelerated approval program, the 
FDA may grant accelerated approval to a product candidate designed to treat a serious or life-threatening condition that provides 
meaningful therapeutic benefit over available therapies upon a determination that the product candidate has an effect on a surrogate 
endpoint or intermediate clinical endpoint that is reasonably likely to predict clinical benefit. The FDA considers a clinical benefit to 
be a positive therapeutic effect that is clinically meaningful in the context of a given disease, such as irreversible morbidity or 
mortality. For the purposes of accelerated approval, a surrogate endpoint is a marker, such as a laboratory measurement, radiographic 
image, physical sign, or other measure that is thought to predict clinical benefit, but is not itself a measure of clinical benefit. An 
intermediate clinical endpoint is a clinical endpoint that can be measured earlier than an effect on irreversible morbidity or mortality 
that is reasonably likely to predict an effect on irreversible morbidity or mortality or other clinical benefit. 
The accelerated approval pathway may be used in cases in which the advantage of a product candidate over available therapy may not 
be a direct therapeutic advantage, but is a clinically important improvement from a patient and public health perspective. If granted, 
accelerated approval is usually contingent on the sponsor’s agreement to conduct, in a diligent manner, additional confirmatory studies 
to verify and describe the drug’s clinical benefit. In December 2024, the FDA approved BIZENGRI® (zenocutuzumab-zbco), the first 
and only treatment indicated for adults with pancreatic adenocarcinoma or NSCLC that are advanced unresectable or metastatic and 
harbor a neuregulin 1 (NRG1) gene fusion who have disease progression on or after prior systemic therapy. These indications were 
approved under accelerated approval based on ORR and DOR and continued approval for these indications may be contingent upon 
verification and description of clinical benefit in a confirmatory trial(s). If such confirmatory studies fail to confirm the drug’s clinical 
benefit or are not completed in a timely manner, the FDA may withdraw its approval of the drug on an expedited basis. In addition,  
the Food and Drug Omnibus Reform Act of 2022, among other things, provided FDA new statutory authority to mitigate potential 
risks to patients from continued marketing of ineffective drugs previously granted accelerated approval. Under these provisions, 
among other things, the FDA may require a sponsor of a product seeking accelerated approval to have a confirmatory trial underway 
prior to such approval being granted.
Prior to seeking accelerated approval for any of our other product candidates, such as petosemtamab and/or MCLA-129, we intend to 
seek feedback from the FDA and will otherwise evaluate our ability to seek and receive accelerated approval. There can be no 
assurance that after our evaluation of the feedback and other factors we will decide to pursue or submit a BLA for accelerated 
approval or any other form of expedited development, review or approval. Furthermore, if we decide to submit an application for 
accelerated approval for our product candidates, there can be no assurance that such application will be accepted or that any expedited 
development, review or approval will be granted on a timely basis, or at all. Similarly, for BIZENGRI®, irrespective of obtaining 
accelerated approval, there can be no assurance that such approval will be maintained or converted to full approval upon the 
completion of confirmatory trial(s) and /or post-marketing requirements or commitments. The FDA or other comparable foreign 
regulatory authorities could also require us to conduct further studies prior to considering our application or granting approval of any 
type. A failure to obtain accelerated approval or any other form of expedited development, review or approval for our product 
candidate would result in a longer time period to commercialization of such product candidate, if any, could increase the cost of 

63
development of such product candidate and could harm our competitive position in the marketplace.A failure to convert to full 
approval or maintain our accelerated approval for BIZENGRI® could also result in lost revenue from potential future royalties and 
reputational harm to our business.
For any of our antibody candidates that obtain regulatory approval, we will be subject to ongoing obligations and continued 
regulatory review, which may result in significant additional expense. Additionally, our antibody candidates, if approved, could be 
subject to labeling and other restrictions and market withdrawal and we may be subject to penalties if we fail to comply with 
regulatory requirements or experience unanticipated problems with our products.
With respect to the accelerated approval we have received for BIZENGRI®, and for any further regulatory approvals that we may 
receive for our antibody candidates, such approval will require the submission of reports to regulatory authorities and surveillance to 
monitor the safety and efficacy of the applicable product, may contain significant limitations related to use restrictions for specified 
age groups, warnings, precautions or contraindications, and may include burdensome post-approval study or risk management 
requirements. For example, although this was not required for with respect to the accelerated approval we have received for 
BIZENGRI®, as a condition for approving any of our other clinical candidates, the FDA may require a Risk Evaluation and 
Mitigation Strategy in order to approve our antibody candidates, which could entail requirements for a medication guide, physician 
training and communication plans or additional elements to ensure safe use, such as restricted distribution methods, patient registries 
and other risk minimization tools. Similar risk management measures may be required by foreign regulatory authorities. In addition, if 
the FDA or foreign regulatory authorities approve our antibody candidates, the manufacturing processes, labeling, packaging, 
distribution, adverse event reporting, storage, advertising, promotion, import, export and recordkeeping for our product candidates will 
be subject to extensive and ongoing regulatory requirements. These requirements include submissions of safety and other post-
marketing information and reports, registration, as well as on-going compliance with cGMPs or similar foreign requirements, and 
GCPs for any clinical trials that we conduct following approval. In addition, manufacturers of drug products and their facilities are 
subject to continual review and periodic, unannounced inspections by the FDA and other regulatory authorities for compliance with 
cGMP or similar foreign regulations and standards. 
If we or a regulatory authority discover previously unknown problems with a product, such as adverse events of unanticipated severity 
or frequency, or problems with the facilities where the product is manufactured, a regulatory authority may impose restrictions on that 
product, the manufacturing facility or us, including requiring recall or withdrawal of the product from the market or suspension of 
manufacturing. In addition, failure to comply with FDA and other comparable foreign regulatory requirements may subject our 
company to administrative or judicially imposed sanctions, including:
•
delays in or the rejection of product approvals;
•
restrictions on our ability to conduct clinical trials, including full or partial clinical holds on ongoing or planned trials;
•
restrictions on the products, manufacturers or manufacturing process;
•
warning or untitled letters;
•
civil and criminal penalties;
•
injunctions;
•
suspension or withdrawal of regulatory approvals;
•
product seizures, detentions or import bans;
•
voluntary or mandatory product recalls and publicity requirements;
•
total or partial suspension of production; and
•
imposition of restrictions on operations, including costly new manufacturing requirements.
The occurrence of any event or penalty described above may inhibit our ability to commercialize our product candidates and generate 
revenue and could require us to expend significant time and resources in response and could generate negative publicity.
The FDA’s and other regulatory authorities’ policies may change, and additional government regulations may be enacted that could 
prevent, limit or delay regulatory approval of our product candidates. If we are slow or unable to adapt to changes in existing 
requirements or the adoption of new requirements or policies, or if we are not able to maintain regulatory compliance, we may lose 
any marketing approval that we may have obtained, and we may not achieve or sustain profitability.

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We also cannot predict the likelihood, nature or extent of government regulation that may arise from future legislation or 
administrative or executive action, either in the United States or abroad.
We may not be successful in our efforts to use and expand our Biclonics® technology platform to build a pipeline of antibody 
candidates or to use our Triclonics® technology platform to build a pipeline of trispecific antibody candidates.
A key element of our strategy is to use and expand our Biclonics® technology platform to build a pipeline of antibody candidates and 
progress these antibody candidates through clinical development for the treatment of a variety of different types of diseases. Although 
our research and development efforts to date have resulted in a pipeline of antibody candidates directed at various cancers, we may not 
be able to develop antibody candidates that are safe and effective. 
Another important element of our strategy is to develop, use and exploit our Triclonics® technology platform to build a pipeline of 
trispecific antibody candidates and collaborate with third parties in potentially researching and developing these trispecific antibody 
candidates through pre-clinical and clinical development for the treatment of a variety of different types of diseases. Although our 
research and development efforts to date have resulted in proof of concept pre-clinical candidates, we may not be able to develop or 
monetize these trispecific antibody candidates or demonstrate in the clinic that they are safe and effective. Even if we are successful in 
continuing to build our bispecific and trispecific pipelines, the potential antibody 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 continue to successfully 
develop and begin to commercialize our bispecific antibody candidates or if we do not successfully develop, collaborate, license or 
begin to commercialize our trispecific antibody candidates, we will face difficulty in obtaining product revenues in future periods, 
which could result in significant harm to our financial position and adversely affect our share price.
Even though we obtained marketing approval of zenocutuzumab in the United States, we may never obtain approval or 
commercialize zenocutuzumab or our other clinical candidates in other major markets, which would limit our ability to realize 
their full market potential.
In order to market any products in a country or territory, we must establish and comply with numerous and varying regulatory 
requirements of such countries or territories regarding safety and efficacy. Clinical trials conducted in one country may not be 
accepted by regulatory authorities in other countries, and regulatory approval in one country does not mean that regulatory approval 
will be obtained in any other country. Approval procedures vary among countries and can involve additional product testing and 
validation and additional administrative review periods. Seeking regulatory approvals in all major markets could result in significant 
delays, difficulties and costs for us and may require additional pre-clinical studies or clinical trials which would be costly and time 
consuming. Regulatory requirements can vary widely from country to country and could delay or prevent the introduction of our 
products in those countries. Satisfying these and other regulatory requirements is costly, time consuming, uncertain and subject to 
unanticipated delays. In addition, our failure to obtain regulatory approval in any country may delay or have negative effects on the 
process for regulatory approval in other countries. We currently only have received approval for zenocutuzumab, as BIZENGRI®,  in 
the United States. We currently do not have any other antibody candidates approved for sale in any jurisdiction, whether in the 
Netherlands, the United States or any other international markets, and we do not have experience in obtaining regulatory approval in 
international markets. If we fail to comply with regulatory requirements in international markets or to obtain and maintain required 
approvals, our target market will be reduced and our ability to realize the full market potential of our products, if any, will be harmed.
Due to our limited resources and access to capital, we must, and have in the past decided to, prioritize development of certain 
antibody candidates over other potential candidates. These decisions may prove to have been wrong and may adversely affect our 
revenues.
Because we have limited resources and access to capital to fund our operations, we must decide which antibody candidates to pursue 
and the amount of resources to allocate to each. Our decisions concerning the allocation of research, collaboration, management and 
financial resources toward particular compounds, antibody candidates or therapeutic areas may not lead to the development of viable 
commercial products and may divert resources away from better opportunities. Similarly, our decisions to delay, terminate or 
collaborate with third parties in respect of certain antibody development programs may also prove not to be optimal and could cause 
us to miss valuable opportunities. If we make incorrect determinations regarding the market potential of our antibody candidates or 
misread trends in the biopharmaceutical industry, in particular for our lead antibody candidates, our business, financial condition and 
results of operations could be materially adversely affected.

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Because we are subject to environmental, health and safety laws and regulations, we may become exposed to liability and 
substantial expenses in connection with environmental compliance or remediation activities which may adversely affect our 
business and financial condition.
Our operations, including our research, development, testing and manufacturing activities, are subject to numerous environmental, 
health and safety laws and regulations. These laws and regulations govern, among other things, the importation, storage, controlled 
use, handling, release and disposal of, and the maintenance of a registry for, hazardous materials and biological materials, such as 
chemical solvents, human cells, animal byproducts, genetically modified organisms, carcinogenic compounds, mutagenic compounds 
and compounds that have a toxic effect on reproduction, laboratory procedures and exposure to blood-borne pathogens. If we fail to 
comply with such laws and regulations, or fail to obtain or maintain relevant permits, we could be subject to fines or other sanctions or 
work stoppages, which could have a material adverse effect on our business, financial condition and results of operations.
As with other companies engaged in activities similar to ours, we face a risk of environmental liability inherent in our current and 
historical activities, including liability relating to releases of or exposure to hazardous or biological materials. Environmental, health 
and safety laws and regulations are becoming more stringent. We may be required to incur substantial expenses in connection with 
future environmental compliance or remediation activities, in which case, our production and development efforts may be interrupted 
or delayed and our financial condition and results of operations may be materially adversely affected.
Our employees, independent contractors, principal investigators, CROs, consultants, vendors and collaborators may engage in 
misconduct or other improper activities, including noncompliance with applicable law, regulatory standards and requirements, 
which could have a material adverse effect on our business.
We are exposed to the risk that our employees, independent contractors, principal investigators, CROs, consultants, vendors and 
collaborators may engage in fraudulent conduct or other illegal activities. Misconduct by these parties could include fraudulent, 
intentional, reckless and/or negligent conduct or unauthorized activities that violate: (i) the regulations of the FDA and other 
regulatory authorities, including those laws that require the reporting of true, complete and accurate information to such authorities; 
(ii) manufacturing standards; (iii) federal and state data privacy, security, fraud and abuse and other healthcare laws and regulations in 
the United States and abroad; (iv) laws that require the reporting of true, complete and accurate financial information and data; or (v) 
their representations or commitments to us regarding their capabilities and performance under existing or future agreements. 
Specifically, 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 may restrict or 
prohibit a wide range of pricing, discounting, marketing and promotion, sales commission, customer incentive programs and other 
business arrangements. Activities subject to these laws could also involve the improper use or misrepresentation of information 
obtained in the course of clinical trials or creating fraudulent data in our pre-clinical studies or clinical trials, which could result in 
regulatory sanctions and cause serious harm to our reputation. It is not always possible to identify and deter misconduct by employees 
and other third parties, and the precautions we take to detect and prevent this activity may not be effective in controlling unknown or 
unmanaged risks or losses or in protecting us from governmental investigations or other actions or lawsuits stemming from a failure to 
comply with such laws or regulations. Additionally, we are subject to the risk that a person or government could allege such fraud or 
other misconduct, even if none occurred. 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 and results of operations, including the imposition 
of significant civil, criminal and administrative penalties, damages, monetary fines, disgorgements, possible exclusion from 
participation in Medicare, Medicaid and other U.S. federal healthcare programs, individual imprisonment, other sanctions, contractual 
damages, reputational harm, diminished profits and future earnings, and curtailment of our operations, any of which could adversely 
affect our ability to operate our business and our results of operations. Additionally, we are subject to the risk that misrepresentations 
regarding independent contractors, principal investigators, CROs, consultants, vendors and collaborators’ capabilities and performance 
under existing or future agreements may lead us to rely upon them for important strategic or operational matters, which could have a 
significant adverse impact on our business and results of operations.
Our research and development activities could be affected or delayed as a result of possible restrictions on animal testing.
Certain laws and regulations require us to test our antibody candidates on animals before initiating clinical trials involving humans. 
Animal testing activities have been the subject of controversy and adverse publicity. Animal rights groups and other organizations and 
individuals have attempted to stop animal testing activities by pressing for legislation and regulation in these areas and by disrupting 
these activities through protests and other means. To the extent the activities of these groups are successful, our research and 
development activities may be interrupted, delayed or become more expensive.

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Risks Related to Regulatory Approval of Our Antibody Candidates
Enacted and future legislation may increase the difficulty and cost for us to obtain marketing approval of and commercialize our 
antibody candidates and may affect the prices we may set. The successful commercialization of our antibody candidates will 
depend in part on the extent to which governmental authorities and health insurers establish adequate coverage and 
reimbursement levels and pricing policies.
In the United States, the EU, and other foreign jurisdictions, there have been, and we expect there will continue to be, a number of 
legislative and regulatory changes and proposed changes to the healthcare system that could affect our future results of operations. In 
particular, there have been and continue to be a number of initiatives at the United States federal and state levels that seek to reduce 
healthcare costs and improve the quality of healthcare. For example, in March 2010, the Patient Protection and Affordable Care Act, 
as amended by the Health Care and Education Reconciliation Act (collectively the ACA) was enacted, which substantially changed 
the way healthcare is financed by both governmental and private insurers. Among the provisions of the ACA, those of greatest 
importance to the pharmaceutical and biotechnology industries include the following:
•
an annual, non-deductible fee on any entity that manufactures or imports certain branded prescription drugs and biologic 
agents, which is apportioned among these entities according to their market share in certain government healthcare 
programs;
•
an increase in the statutory minimum rebates a manufacturer must pay under the Medicaid Drug Rebate Program to 
23.1% and 13.0% of the average manufacturer price for branded and generic drugs, respectively;
•
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;
•
extension of a manufacturer’s Medicaid rebate liability to covered drugs dispensed to individuals who are enrolled in 
Medicaid managed care organizations;
•
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;
•
expansion of the entities eligible for discounts under the Public Health Service pharmaceutical pricing program;
•
a new Patient-Centered Outcomes Research Institute to oversee, identify priorities in, and conduct comparative clinical 
effectiveness research, along with funding for such research; and
•
establishment of a Center for Medicare and Medicaid Innovation at the Centers for Medicare & Medicaid Services 
(CMS) to test innovative payment and service delivery models to lower Medicare and Medicaid spending, potentially 
including prescription drug spending.
Since its enactment, there have been judicial, executive and Congressional challenges to certain aspects of the ACA. On June 17, 
2021, the U.S. Supreme Court dismissed the most recent judicial challenge to the ACA brought by several states without specifically 
ruling on the constitutionality of the ACA.  
In addition, other legislative changes have been proposed and adopted in the United States since the ACA was enacted. These changes 
include the American Rescue Plan Act of 2021, which eliminated the statutory Medicaid drug rebate cap beginning January 1, 2024. 
The rebate was previously capped at 100% of a drug's average manufacturer price. Moreover, payment methodologies, including 
payment for companion diagnostics, may be subject to changes in healthcare legislation and regulatory initiatives. In addition, recently 
there has been heightened governmental scrutiny over the manner in which manufacturers set prices for their marketed products, 
which has resulted in several Congressional inquiries and proposed and enacted legislation designed to, among other things, bring 
more transparency to product pricing, review the relationship between pricing and manufacturer patient programs, and reform 
government program reimbursement methodologies for drug products. Most recently, in August 2022, the Inflation Reduction Act of 
2022, or IRA, was signed into law. Among other things, the IRA requires manufacturers of certain drugs to engage in price 
negotiations with Medicare (beginning in 2026), with prices that can be negotiated subject to a cap; imposes rebates under Medicare 
Part B and Medicare Part D to penalize price increases that outpace inflation (first due in 2023); and replaces the Part D coverage gap 
discount program with a new discounting program (which began in 2025). The IRA permits the Secretary of the Department of Health 
and Human Services (HHS) to implement many of these provisions through guidance, as opposed to regulation, for the initial years. 
HHS has and will continue to issue and update guidance as these programs are implemented. CMS has published the negotiated prices 

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for the initial ten drugs, which will first be effective in 2026, and the list of the subsequent 15 drugs that will be subject to negotiation, 
although the Medicare drug price negotiation program is currently subject to legal challenges.  
We expect that additional U.S. federal healthcare reform measures will be adopted in the future, any of which could limit the amounts 
that the U.S. federal government will pay for healthcare products and services, which could result in reduced demand for our antibody 
candidates or additional pricing pressures.
Individual states in the United States have also become increasingly active 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. Legally mandated price controls on payment amounts by third-party 
payors or other restrictions could harm our business, results of operations, financial condition and prospects. In addition, regional 
healthcare authorities 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. This could reduce the ultimate demand 
for any future products or put pressure on our product pricing, which could negatively affect our business, results of operations, 
financial condition and prospects.
In the EU, similar political, economic and regulatory developments may affect our ability to profitably commercialize any future 
products. In addition to continuing pressure on prices and cost containment measures, legislative developments at the EU or member 
state level may result in significant additional requirements or obstacles that may increase our operating costs. The delivery of 
healthcare in the EU, including the establishment and operation of health services and the pricing and reimbursement of medicines, is 
almost exclusively a matter for national, rather than EU, law and policy. National governments and health service providers have 
different priorities and approaches to the delivery of health care and the pricing and reimbursement of products in that context. In 
general, however, the healthcare budgetary constraints in most EU member states have resulted in restrictions on the pricing and 
reimbursement of medicines by relevant health service providers. Coupled with ever-increasing EU and national regulatory burdens 
on those wishing to develop and market products, this could prevent or delay marketing approval of our antibody candidates, restrict 
or regulate post-approval activities and affect our ability to commercialize any products for which we obtain marketing approval. In 
international markets, reimbursement and healthcare payment systems vary significantly by country, and many countries have 
instituted price ceilings on specific products and therapies.
In the EU, similar developments may affect our ability to profitably commercialize our product candidates, if approved. On December 
13, 2021, Regulation No 2021/2282 on Health Technology Assessment (HTA) amending Directive 2011/24/EU, was adopted. The 
Regulation entered into force in January 2022 and has been applicable since January 2025, with phased implementation based on the 
type of product, i.e. oncology and advanced therapy medicinal products as of 2025, orphan medicinal products as of 2028, and all 
other medicinal products by 2030. The Regulation intends to boost cooperation among EU member states in assessing health 
technologies, including new medicinal products, and provide the basis for cooperation at the EU level for joint clinical assessments in 
these areas. It will permit EU member states to use common HTA tools, methodologies, and procedures across the EU, working 
together in four main areas, including joint clinical assessment of the innovative health technologies with the highest potential impact 
for patients, joint scientific consultations whereby developers can seek advice from HTA authorities, identification of emerging health 
technologies to identify promising technologies early, and continuing voluntary cooperation in other areas. Individual EU member 
states will continue to be responsible for assessing non-clinical (e.g., economic, social, ethical) aspects of health technology, and 
making decisions on pricing and reimbursement.
Finally, policies of the individual government agencies, including the FDA or similar regulatory authorities, may change and 
additional government regulations may be enacted that could prevent, limit or delay regulatory approval of our product candidates. If 
we or our collaborators are slow or unable to adapt to changes in existing requirements or the adoption of new requirements or 
policies, or if we or our collaborators are not able to maintain regulatory compliance, our antibody candidates may lose any regulatory 
approval that may have been obtained and we may not achieve or sustain profitability, which would adversely affect our business.

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If we are required by the FDA or similar authorities to obtain approval (or clearance, or certification) of a companion diagnostic 
test in connection with approval of any of our antibody candidates, and we do not obtain or face delays in obtaining approval (or 
clearance, or certification) of a diagnostic device, we will not be able to commercialize such product candidate and our ability to 
generate revenue will be materially impaired.
If safe and effective use of any of our antibody candidates depends on a diagnostic that is not otherwise commercially available, then 
the FDA may require approval or clearance of that diagnostic, known as a companion diagnostic, at the same time that the FDA 
approves our antibody candidates, if at all or as a post-marketing commitment. According to FDA guidance, if the FDA determines 
that a companion diagnostic device is essential to the safe and effective use of a novel therapeutic product or indication, the FDA 
generally will not approve the therapeutic product or new therapeutic product indication if the companion diagnostic is not also 
approved or cleared for that indication. If a satisfactory companion diagnostic is not commercially available, we may be required to 
develop or obtain one that would be subject to regulatory approval requirements. The process of obtaining or creating such diagnostics 
is time consuming and costly and associated with numerous risks and uncertainties.
Companion diagnostics are developed in conjunction with clinical programs for the associated product and are subject to regulation as 
medical devices by the FDA and comparable regulatory authorities, and, to date, the FDA has generally required premarket approval 
of companion diagnostics labeled for use with cancer therapies. The approval of a companion diagnostic as part of the therapeutic 
product’s labeling limits the use of the therapeutic product to only those patients who express the specific genetic alteration that the 
companion diagnostic was developed to detect.
If the FDA or a comparable regulatory authority requires approval (or clearance, or certification) of a companion diagnostic for any of 
our antibody candidates, whether before or after such candidate obtains marketing approval, difficulties may be encountered in 
developing and obtaining approval for such antibody candidate. Any delay or failure by us or third-party collaborators to develop or 
obtain regulatory approval (or clearance, or certification) of a companion diagnostic could delay or prevent approval or continued 
marketing of such antibody candidate.
We may also experience delays in developing a sustainable, reproducible and scalable manufacturing process for the companion 
diagnostic or in transferring that process to commercial partners or negotiating insurance reimbursement plans, all of which may 
prevent us from completing our clinical trials or commercializing our product candidate, if approved, on a timely or profitable basis, if 
at all.
Approval, clearance or certification of companion diagnostics may be subject to further legislative or regulatory reforms notably in the 
EU. On May 25, 2017, the new In Vitro Medical Devices Regulation (2017/746) (IVDR) entered into force. The IVDR repeals and 
replaces the EU In Vitro Diagnostic Medical Devices Directive. Unlike directives, which must be implemented into the national laws 
of the EEA countries, regulations are directly applicable, i.e., without the need for adoption of EEA countries laws implementing 
them, in all EEA countries and are intended to eliminate current differences in the regulation of medical devices among EEA 
countries. The IVDR, among other things, is intended to establish a uniform, transparent, predictable and sustainable regulatory 
framework across the EEA for medical devices and ensure a high level of safety and health while supporting innovation. The IVDR 
became applicable on May 26, 2022. Following subsequent legislative changes, European institutions adopted  a “progressive” roll-
out of the IVDR to prevent disruption in the supply of in vitro diagnostic medical devices. Therefore, the IVDR applied since May 26, 
2022 but there is a tiered system extending the grace period for many devices (depending on their risk classification) before they have 
to be fully compliant with the Regulation.
The regulation of companion diagnostics is subject to further requirements since the IVDR became applicable and introduced a new 
classification system for companion diagnostics which are now specifically defined as diagnostic tests that support the safe and 
effective use of a specific medicinal product, by identifying patients that are suitable or unsuitable for treatment. Companion 
diagnostics will have to undergo a conformity assessment by a notified body. Before it can issue an EU certificate, the notified body 
must seek a scientific opinion from the EMA on the suitability of the companion diagnostic to the medicinal product concerned if the 
medicinal product falls exclusively within the scope of the centralized procedure for the authorization of medicines, or the medicinal 
product is already authorized through the centralized procedure, or a marketing authorization application for the medicinal product has 
been submitted through the centralized procedure. For other substances, the notified body can seek the opinion from national 
competent authorities or the EMA. These modifications may make it more difficult and costly for us to obtain regulatory clearances, 
approvals or certifications for our companion diagnostics or to manufacture, market or distribute our products after clearance, 
approval or certification is obtained.

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Disruptions at the FDA and other government agencies caused by funding shortages or global health concerns could hinder their 
ability to hire, retain or deploy key leadership and other personnel, or otherwise prevent new or modified products from being 
developed, approved or commercialized in a timely manner or at all, which could negatively impact our business.
The ability of the FDA and foreign regulatory authorities to review and or approve new products can be affected by a variety of 
factors, including government budget and funding levels, statutory, regulatory, and policy changes, the FDA’s or foreign regulatory 
authorities’ ability to hire and retain key personnel and accept the payment of user fees, and other events that may otherwise affect the 
FDA’s or foreign regulatory authorities’ ability to perform routine functions. Average review times at the FDA and foreign regulatory 
authorities have fluctuated in recent years as a result. In addition, government funding of other government agencies that fund research 
and development activities is subject to the political process, which is inherently fluid and unpredictable. Disruptions at the FDA and 
other agencies, may also slow the time necessary for new drugs and biologics to be reviewed and/or approved by necessary 
government agencies, which would adversely affect our business. For example, from time to time, the U.S. government has shut down 
several times and certain regulatory agencies, such as the FDA, have had to furlough critical FDA employees and stop critical 
activities.
Separately, in response to the COVID-19 pandemic, the FDA postponed most inspections of domestic and foreign manufacturing 
facilities at various points. If a prolonged government shutdown occurs, or if global health concerns prevent the FDA or other 
regulatory authorities from conducting their regular inspections, reviews, or other regulatory activities, it could significantly impact 
the ability of the FDA or other regulatory authorities to timely review and process our regulatory submissions, which could have a 
material adverse effect on our business.
We may be subject to healthcare laws, regulation and enforcement; our failure to comply with these laws could harm our results of 
operations and financial conditions.
Although we do not currently have any products on the market, beyond BIZENGRI®, which we have licensed to PTx to 
commercialize in the U.S. for the labeled indications in NRG1+ cancer, if we obtain FDA approval for any of our antibody candidates 
and begin commercializing those products in the United States, our operations may be directly, or indirectly through our customers 
and third-party payors, subject to various U.S. federal and state healthcare laws and regulations, including, without limitation, the U.S. 
federal Anti-Kickback Statute. Healthcare providers, physicians and others play a primary role in the recommendation and 
prescription of any products for which we obtain marketing approval. These laws may impact, among other things, our proposed sales, 
marketing and education programs and constrain our financial arrangements and relationships with healthcare providers, physicians 
and other parties through which we market, sell and distribute our products for which we obtain marketing approval. In addition, we 
may be subject to additional healthcare, statutory and regulatory requirements and enforcement by foreign regulatory authorities in 
jurisdictions in which we conduct our business. The laws that may affect our ability to operate include:
•
the U.S. federal Anti-Kickback Statute, which prohibits, among other things, persons or entities from knowingly and 
willfully soliciting, offering, receiving or paying any remuneration (including any kickback, bribe, or certain rebate), 
directly or indirectly, overtly or covertly, in cash or in kind, to induce or reward either the referral of an individual for, or 
the purchase, lease, order or recommendation of, any good, facility, item or service, for which payment may be made, in 
whole or in part, under U.S. federal and state healthcare programs such as Medicare and Medicaid; a person or entity 
does not need to have actual knowledge of the statute or specific intent to violate it in order to have committed a 
violation;
•
the U.S. federal false claims and civil monetary penalties laws, including the civil False Claims Act, which, among other 
things, impose 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, to the U.S. federal government, 
claims for payment or approval that are false or fraudulent, knowingly making, using or causing to be made or used, a 
false record or statement material to a false or fraudulent claim, or from knowingly making a false statement to avoid, 
decrease or conceal an obligation to pay money to the U.S. federal government. In addition, the government may assert 
that a claim including items and services resulting from a violation of the U.S. federal Anti-Kickback Statute constitutes 
a false or fraudulent claim for purposes of the False Claims Act;
•
the U.S. federal Health Insurance Portability and Accountability Act of 1996 (HIPAA) which imposes criminal and civil 
liability for, among other things, knowingly and willfully executing, or attempting to execute, a scheme to defraud any 
healthcare benefit program, or knowingly and willfully falsifying, concealing or covering up a material fact or making 
any materially false statement, in connection with the delivery of, or payment for, healthcare benefits, items or services; 

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similar to the U.S. federal Anti-Kickback Statute, a person or entity does not need to have actual knowledge of the 
statute or specific intent to violate it in order to have committed a violation;
•
the FD&C Act which prohibits, among other things, the adulteration or misbranding of drugs, biologics and medical 
devices;
•
the U.S. federal legislation commonly referred to as Physician Payments Sunshine Act, enacted as part of the ACA, and 
its implementing regulations, which requires certain manufacturers of drugs, devices, biologics and medical supplies that 
are reimbursable under Medicare, Medicaid, or the Children’s Health Insurance Program to report annually to the CMS 
information related to certain payments and other transfers of value to physicians (defined to include doctors, dentists, 
optometrists, podiatrists and chiropractors), certain other health care professionals including physician assistants and 
nurse practitioners, and teaching hospitals, as well as ownership and investment interests held by the physicians 
described above and their immediate family members;
•
analogous state laws and regulations, including: state anti-kickback and false claims laws, which may apply to our 
business practices, including but not limited to, research, distribution, sales and marketing arrangements and claims 
involving healthcare items or services reimbursed by any third-party payor, including private insurers; state laws that 
require pharmaceutical companies to comply with the pharmaceutical industry’s voluntary compliance guidelines and the 
relevant compliance guidance promulgated by the U.S. federal government, or otherwise restrict payments that may be 
made to healthcare providers and other potential referral sources; and state laws and regulations that require drug 
manufacturers to file reports relating to pricing and marketing information, and that require the tracking and reporting of 
gifts and other remuneration and items of value provided to healthcare professionals and entities; and 
•
European and other foreign law equivalents of each of the laws, including reporting requirements detailing interactions 
with and payments to healthcare providers.
Ensuring that our internal operations and future business arrangements with third parties comply with applicable healthcare laws and 
regulations could involve substantial costs. It is possible that governmental authorities will conclude that our business practices do not 
comply with current or future statutes, regulations, agency guidance or case law involving applicable fraud and abuse or other 
healthcare laws and regulations. If our operations are found to be in violation of any of the laws described above or any other 
governmental laws and regulations that may apply to us, we may be subject to significant penalties, including civil, criminal and 
administrative penalties, damages, fines, exclusion from U.S. government funded healthcare programs, such as Medicare and 
Medicaid, disgorgement, individual imprisonment, contractual damages, reputational harm, diminished profits, reporting obligations 
and oversight if we become subject to a corporate integrity agreement or other agreement, and the curtailment or restructuring of our 
operations. If any of the physicians or other providers or entities with whom we expect to do business is found not to be in compliance 
with applicable laws, they may be subject to criminal, civil or administrative sanctions, including exclusions from government funded 
healthcare programs and imprisonment. If any of the above occur, it could adversely affect our ability to operate our business and our 
results of operations. Further, defending against any such actions can be costly, time-consuming and may require significant personnel 
resources. Therefore, even if we are successful in defending against any such actions that may be brought against us, our business may 
be impaired.
We face potential liability related to the privacy of health or other personal information we obtain from clinical trials sponsored by 
us or our collaborators, from research institutions, and directly from individuals.
Most health care providers, including research institutions from which we or our collaborators obtain patient health information, are 
subject to privacy and security regulations promulgated under HIPAA, as amended by HITECH. HIPAA imposes privacy, security 
and data breach reporting obligations with respect to individually identifiable health information upon “covered entities” (health plans, 
health care clearinghouses and certain health care providers), and their respective “business associates” (individuals or entities that 
create, receive, maintain or transmit individually identifiable health information in connection with providing a service for or on 
behalf of a covered entity, as well as their covered subcontractors). Entities that are found to be in violation of HIPAA as the result of 
a breach of unsecured PHI, a complaint about privacy practices, or an audit by HHS, may be subject to significant civil, criminal and 
administrative fines and penalties and/or additional reporting and oversight obligations. Any person may be prosecuted under 
HIPAA’s criminal provisions either directly or under aiding-and-abetting or conspiracy principles. Consequently, depending on the 
facts and circumstances, we could face substantial criminal penalties if we knowingly receive individually identifiable health 
information from a HIPAA-covered health care provider or research institution that has not satisfied HIPAA’s requirements for the 
disclosure of such information. 

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In addition, we may maintain sensitive personally identifiable information, including health information, that we receive throughout 
the clinical trial process, in the course of our research collaborations, and directly from individuals (or their healthcare providers) who 
enroll in our patient assistance programs. Even when HIPAA does not apply, according to the Federal Trade Commission (FTC), 
failing to take appropriate steps to keep consumers’ personal information secure constitutes unfair acts or practices in or affecting 
commerce in violation of Section 5(a) of the Federal Trade Commission Act. The FTC has authority to initiate enforcement actions 
against entities that mislead customers about HIPAA compliance, make deceptive statements about privacy and data sharing in 
privacy policies, fail to limit third-party use of personal health information, fail to implement policies to protect personal health 
information or engage in other unfair practices that harm customers or that may violate Section 5(a)  of the FTC Act. The FTC expects 
a company’s data security measures to be reasonable and appropriate in light of the sensitivity and volume of consumer information it 
holds, the size and complexity of its business, and the cost of available tools to improve security and reduce vulnerabilities. 
Individually identifiable health information is considered sensitive data that merits stronger safeguards. Additionally, federal and state 
consumer protection laws are increasingly being applied by FTC and states’ attorneys general to regulate the collection, use, storage, 
and disclosure of personal or personally identifiable information, through websites or otherwise, and to regulate the presentation of 
website content. The FTC’s guidance for appropriately securing consumers’ personal information is similar to what is required by the 
HIPAA Security Rule. As such, we, our collaborators, research institutions, health care providers and other entities that provide 
personally identifiable information to us may be subject to state information security laws, and state laws requiring notification of 
affected individuals and state regulators in the event of a breach of personal information, which is a broader class of information than 
the health information protected by HIPAA. 
The United States and global data protection landscape is rapidly evolving, and we may be affected by or subject to new or amended 
laws and regulations in the future. Certain states have also adopted privacy and security laws and regulations governing the privacy, 
processing and protection of personal information. For example, the CCPA, among other things, creates data privacy obligations for 
covered companies and provides individual privacy rights to California residents, including the right to delete and to opt out of certain 
disclosures of their information. The CCPA also creates a private right of action with statutory damages for certain data breaches, and 
has increased the risks associated with a data breach. Although the law includes limited exceptions, including for “protected health 
information” maintained by a covered entity or business associate, it may regulate or impact our processing of certain personal 
information depending on the context. Additional compliance investment and potential business process changes may also be required. 
Similar laws have been proposed in other states and at the federal level, reflecting a trend toward more stringent privacy legislation in 
the United States. The enactment of such laws could have potentially conflicting requirements that would make compliance 
challenging. In the event that we are subject to or affected by domestic privacy and data protection laws, any liability from failure to 
comply with the requirements of these laws could adversely affect our financial condition, our ability to operate in certain jurisdictions 
and our reputation.
Our and our collaborators’ clinical trial programs and research collaborations outside the U.S. may implicate international data 
protection laws, including, in the Europe Economic Area (EEA), the GDPR, UK GDPR and local laws further implementing or 
supplementing the GDPR. The GDPR imposes more stringent operational requirements for processors and controllers of personal data 
including requirements for such companies to be able to ensure and be able to demonstrate compliance with the GDPR. If our or our 
collaborators’ privacy or data security measures fail to comply with the GDPR requirements, we may be subject to litigation, 
regulatory investigations, enforcement notices requiring us to change the way we use personal data and/or fines of up to €20 million or 
up to 4% of the total worldwide annual turnover of the preceding financial year, whichever is higher. In addition to statutory 
enforcement, a non-compliance can lead to compensation claims by affected individuals, negative publicity and a potential loss of 
business. 
Among other requirements, the GDPR regulates transfers of personal data subject to the GDPR to third countries that have not been 
found to provide adequate protection to such personal data, including the United States, and the efficacy and longevity of current 
transfer mechanisms between the EEA and the United States remains uncertain. Such transfers need to be legitimized by a valid 
transfer mechanism under the GDPR. Case law from the Court of Justice of the European Union (CJEU) states that reliance on the 
standard contractual clauses - a standard form of contract approved by the European Commission as an adequate personal data transfer 
mechanism - alone may not necessarily be sufficient in all circumstances and that transfers must be assessed on a case-by-case basis. 
On July 10, 2023, the European Commission adopted its Adequacy Decision in relation to the new EU-US Data Privacy Framework 
(DPF), rendering the DPF effective as a GDPR transfer mechanism to U.S. entities self-certified under the DPF. The DPF also 
introduced a new redress mechanism for EU citizens which addresses a key concern in the previous CJEU judgments and may mean 
transfers under standard contractual clauses are less likely to be challenged in future. We currently rely on the EU standard contractual 
clauses and the UK Addendum to the EU standard contractual clauses as relevant to transfer personal data outside the EEA and the 
UK, including to the United States, with respect to both intragroup and third party transfers. We expect the existing legal complexity 

72
and uncertainty regarding international personal data transfers to continue. In particular, we expect the DPF Adequacy Decision to be 
challenged and international transfers to the United States and to other jurisdictions more generally to continue to be subject to 
enhanced scrutiny by regulators. As a result, we may have to make certain operational changes and implement revised standard 
contractual clauses and other relevant documentation for existing data transfers arrangements within required time frames.
Further, following the withdrawal of the UK from the EU on January 31, 2020, and the expiration of the transition period, from 
January 1, 2021, we have had to comply with the GDPR and separately the UK GDPR, with each regime having the ability to fine up 
to the greater of €20 million/ £17 million or 4% of global turnover. On October 12, 2023, the UK Extension to the DPF came into 
effect (as approved by the UK Government), as a data transfer mechanism from the U.K. to U.S. entities self-certified under the DPF. 
As we continue to expand into other foreign countries and jurisdictions, we may be subject to additional laws and regulations that may 
affect how we conduct business.
Although we work to comply with applicable laws, regulations and standards, our contractual obligations and other legal obligations, 
these requirements are evolving and may be modified, interpreted and applied in an inconsistent manner among jurisdictions in which 
we operate. We are likely to be required to expend significant capital and other resources to ensure ongoing compliance with 
applicable privacy and data security laws both inside and outside the United States. Claims that we have violated individuals’ privacy 
rights or breached our contractual obligations regardless of merit and even if we are not found liable, could be expensive and time-
consuming to defend and could result in adverse publicity that could harm our business.
Claims that we or any collaborators fail to comply with applicable federal, state, or local, legal or regulatory requirements, could 
subject us to a range of regulatory actions that could affect our or any collaborators’ ability to seek to commercialize our antibody 
candidates, if approved. Any threatened or actual government enforcement action could also generate adverse publicity and require 
that we devote substantial resources that could otherwise be used in other aspects of our business.
Risks Related to Commercialization of Our Antibody Candidates
We operate in highly competitive and rapidly changing industries, which may result in others discovering, developing or 
commercializing competing products before or more successfully than we do.
The biopharmaceutical and pharmaceutical industries are highly competitive and subject to significant and rapid technological change. 
Our success is highly dependent on our ability to discover, develop and obtain marketing approval for new and innovative products on 
a cost-effective basis and to market them successfully. In doing so, we face and will continue to face intense competition from a 
variety of businesses, including large, fully integrated pharmaceutical companies, specialty pharmaceutical companies and 
biopharmaceutical companies, academic institutions, government agencies and other private and public research institutions in 
Europe, the United States and other jurisdictions. These organizations may have significantly greater resources than we do and 
conduct similar research, seek patent protection and establish collaborative arrangements for research, development, manufacturing 
and marketing of products that compete with our antibody candidates.
With the proliferation of new drugs and therapies into oncology, we expect to face increasingly intense competition as new 
technologies become available. If we fail to stay at the forefront of technological change, we may be unable to compete effectively. 
Any antibody candidates that we successfully develop and commercialize will compete with existing therapies and new therapies that 
may become available in the future. The highly competitive nature of and rapid technological changes in the biotechnology and 
pharmaceutical industries could render our antibody candidates or our technology obsolete, less competitive or uneconomical. Our 
competitors may, among other things: 
•
have significantly greater financial, manufacturing, marketing, drug development, technical and human resources than 
we do;
•
develop and commercialize products that are safer, more effective, less expensive, more convenient or easier to 
administer, or have fewer or less severe side effects;
•
obtain quicker regulatory approval;
•
establish superior proprietary positions covering our products and technologies;
•
implement more effective approaches to sales and marketing; or
•
form more advantageous strategic alliances.

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Should any of these factors occur, our business, financial condition and results of operations could be materially adversely affected.
In addition, existing and future collaborators may decide to market and sell products that compete with the antibody candidates that 
we have agreed to license to them. While we have agreements governing their committed activities, we have limited influence over 
their actual performance, and any competition by our collaborators could also have a material adverse effect on our future business, 
financial condition and results of operations.
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, retaining manufacturers to produce 
clinical trial materials, as well as in acquiring technologies complementary to, or necessary for, our programs.
If we fail to obtain orphan drug designation for our antibody candidates, or obtain or maintain orphan drug exclusivity for our 
products, or lose or fail to add to such designation for zenocutuzumab in the United States, our competitors may sell products to 
treat the same conditions and our revenue will be reduced.
Under the Orphan Drug Act, the FDA may designate a product as an orphan drug if it is intended to treat a rare disease or condition, 
defined as a patient population of fewer than 200,000 in the United States, or a patient population greater than 200,000 in the United 
States where there is no reasonable expectation that the cost of developing the drug will be recovered from sales in the United States. 
In the EU, a medicinal product may be designated as orphan if (1) it is intended for the diagnosis, prevention or treatment of a life-
threatening or chronically debilitating condition; (2) either (a) such condition affects no more than five in 10,000 persons in the EU 
when the application is made, or (b) the product, without the benefits derived from orphan status, would not generate sufficient return 
in the EU to justify investment; and (3) there exists no satisfactory method of diagnosis, prevention or treatment of such condition 
authorized for marketing in the EU, or if such a method exists, the product will be of significant benefit to those affected by the 
condition. Upon grant of a marketing authorization (MA), orphan medicinal products are entitled to a ten-year period of market 
exclusivity for the approved therapeutic indication, which means that during this period, the regulatory authorities cannot accept 
another application for a MA or grant a MA or accept an application to extend an existing MA for the same indication, in respect of a 
similar medicinal product. The application for orphan designation must be submitted before the MA application (MAA). The applicant 
will receive a fee reduction for the MAA if the orphan designation has been granted, but not if the designation is still pending at the 
time the MA is submitted. Orphan designation does not convey any advantage in, or shorten the duration of, the regulatory review and 
approval process.
In the United States, orphan drug designation entitles a party to potential financial incentives such as opportunities for grant funding 
towards clinical trial costs, tax advantages and user-fee waivers. In addition, if a product receives the first FDA approval for the 
disease or condition for which it has orphan designation, the product is entitled to orphan drug exclusivity, which means the FDA may 
not approve any other application to market the same drug for the same disease or condition for a period of seven years, except in 
limited circumstances, such as a showing of clinical superiority over the product with orphan exclusivity or where the manufacturer is 
unable to assure sufficient product quantity. For example, in connection with the FDA’s accelerated approval of BIZENGRI® , the 
FDA granted seven years of orphan exclusivity for zenocutuzumab-zbco for the treatment of adults with advanced unresectable or 
metastatic pancreatic adenocarcinoma harboring a NRG1 gene fusion with disease progression on or after prior systemic therapy. In 
the EU, orphan designation entitles a party to potential financial incentives such as reduction of fees or fee waivers and ten years of 
market exclusivity following drug or biological product approval. This period may be reduced to six years if the orphan designation 
criteria are no longer met, including where it is shown that the product is sufficiently profitable not to justify maintenance of market 
exclusivity or where the prevalence of the condition has increased above the threshold.
We potentially may seek additional orphan drug designations from the FDA and foreign regulatory authorities for other clinical assets, 
where supported by data in the appropriate disease or condition that meet the criteria for orphan status.We may not be the first to 
obtain marketing approval for any particular orphan disease or condition due to the uncertainties associated with developing 
pharmaceutical products. In addition, exclusive marketing rights in the United States may be limited if we seek approval for a disease 
or condition broader than the orphan-designated disease or condition or may be lost if the FDA later determines that the request for 
designation was materially defective or if the manufacturer is unable to assure sufficient quantities of the product to meet the needs of 
patients with the rare disease or condition. Further, even if we obtain orphan drug exclusivity for a product, that exclusivity may not 
effectively protect the product from competition because different drugs with different active moieties can be approved for the same 
condition. Even after an orphan drug is approved, the FDA or foreign regulatory authorities can subsequently approve the same drug 
with the same active moiety for the same condition if the FDA or foreign regulatory authorities concludes that the later drug is safer, 
more effective, or makes a major contribution to patient care. Orphan drug designation neither shortens the development time or 

74
regulatory review time of a drug nor gives the drug any advantage in the regulatory review or approval process. In addition, while we 
intend to seek orphan drug designation, when appropriate, we may not receive such designation.
The successful commercialization of our antibody candidates will depend in part on the extent to which governmental authorities 
and health insurers establish adequate coverage, reimbursement levels and pricing policies. Failure to obtain or maintain 
adequate coverage and reimbursement for our antibody candidates, if approved, could limit our ability to market those products 
and decrease our ability to generate revenue.
The availability and adequacy of coverage and reimbursement by governmental healthcare programs such as Medicare and Medicaid, 
private health insurers and other third-party payors are essential for most patients to be able to afford products such as our antibody 
candidates, assuming approval. Our ability to achieve acceptable levels of coverage and reimbursement for products by governmental 
authorities, private health insurers and other organizations will have an effect on our ability to successfully commercialize and attract 
additional collaborators to invest in the development of our antibody candidates. Assuming we obtain coverage for a given product by 
a third-party payor, the resulting reimbursement payment rates may not be adequate or may require co-payments that patients find 
unacceptably high. We cannot be sure that coverage and reimbursement in the United States, the EU or elsewhere will be available for 
any product that we may develop, and any reimbursement that may become available may be decreased or eliminated in the future. 
Third-party payors increasingly are challenging prices charged for pharmaceutical products and services, and many third-party payors 
may refuse to provide coverage and reimbursement for particular drugs when an equivalent generic drug or a less expensive therapy is 
available. It is possible that a third-party payor may consider our antibody candidate and other therapies as substitutable and only offer 
to reimburse patients for the less expensive product. Even if we show improved efficacy or improved convenience of administration 
with our antibody candidate, pricing of existing drugs may limit the amount we will be able to charge for our antibody candidate. 
These payors may deny or revoke the reimbursement status of a given drug product or establish prices for new or existing marketed 
products at levels that are too low to enable us to realize an appropriate return on our investment in product development. If 
reimbursement is not available or is available only at limited levels, we may not be able to successfully commercialize our antibody 
candidates and may not be able to obtain a satisfactory financial return on products that we may develop.
There is significant uncertainty related to the insurance coverage and reimbursement of newly approved products. In the United States, 
third-party payors, including private and governmental payors, such as the Medicare and Medicaid programs, play an important role in 
determining the extent to which new drugs and biologics will be covered. The Medicare and Medicaid programs increasingly are used 
as models for how private payors and other governmental payors develop their coverage and reimbursement policies for drugs and 
biologics. Some third-party payors may require pre-approval of coverage for new or innovative devices or drug therapies before they 
will reimburse health care providers who use such therapies. It is difficult to predict at this time what third-party payors will decide 
with respect to the coverage and reimbursement for our antibody candidates, if approved.
Obtaining and maintaining reimbursement status is time-consuming and costly. No uniform policy for coverage and reimbursement 
for drug products exists among third-party payors in the United States. Therefore, coverage and reimbursement for drug products can 
differ significantly from payor to payor. As a result, the coverage determination process is often a time-consuming and costly process 
that will require us to provide scientific and clinical support for the use of any future products to each payor separately, with no 
assurance that coverage and adequate reimbursement will be applied consistently or obtained in the first instance. Furthermore, rules 
and regulations regarding reimbursement change frequently, in some cases at short notice, and we believe that changes in these rules 
and regulations are likely.
Outside the United States, international operations are generally subject to extensive governmental price controls and other market 
regulations, and we believe the increasing emphasis on cost-containment initiatives in Europe, Canada, and other countries has and 
will continue to put pressure on the pricing and usage of our antibody candidates, if approved. In many countries, the prices of medical 
products are subject to varying price control mechanisms as part of national health systems. Other countries allow companies to fix 
their own prices for medical products, but monitor and control company profits. Additional foreign price controls or other changes in 
pricing regulation could restrict the amount that we are able to charge for our antibody candidates, if approved. Accordingly, in 
markets outside the United States, the reimbursement for our products may be reduced compared with the United States and may be 
insufficient to generate commercially reasonable revenue and profits.
Moreover, increasing efforts by governmental and third-party payors in the United States and abroad to cap or reduce healthcare costs 
may cause such organizations to limit both coverage and the level of reimbursement for newly approved products and, as a result, they 
may not cover or provide adequate payment for our antibody candidates, if approved. We expect to experience pricing pressures in 
connection with the sale of any of our antibody candidates that are approved due to the trend toward managed healthcare, the 
increasing influence of health maintenance organizations, and additional legislative changes. The downward pressure on healthcare 

75
costs in general, particularly prescription drugs and surgical procedures and other treatments, has become very intense. As a result, 
increasingly high barriers are being erected to the entry of new products.
In addition, even if a pharmaceutical product obtains a marketing authorization in the EU, there can be no assurance that 
reimbursement for such product will be secured on a timely basis or at all.
Our products may not gain market acceptance, in which case we may not be able to generate product revenues, which will 
materially adversely affect our business, financial condition and results of operations.
Even though the FDA granted accelerated approval for BIZENGRI® for the labeled indications, any other regulatory authority 
approves the marketing of any of our other antibody candidates that we develop on our own or with a collaborator, physicians, 
healthcare providers, patients or the medical community may not accept or use them. If these products do not achieve an adequate 
level of acceptance, we may not generate significant product revenues or any profits from operations. The degree of market 
acceptance of any of our antibody candidates that are approved will depend on a variety of factors, including:
•
the timing of market introduction;
•
the number and clinical profile of competing products;
•
our ability to provide acceptable evidence of safety and efficacy;
•
the prevalence and severity of any side effects;
•
relative convenience and ease of administration;
•
cost-effectiveness;
•
patient diagnostics and screening infrastructure in each market;
•
marketing and distribution support;
•
availability of adequate coverage, reimbursement and adequate payment from health maintenance organizations and 
other insurers, both public and private; and
•
other potential advantages over alternative treatment methods.
Failure of our antibody candidates, if approved, to gain market acceptance will have a material adverse impact on our ability to 
generate revenues to provide a satisfactory, or any, return on our investments. Even if some products achieve market acceptance, the 
market may prove not to be large enough to allow us to generate significant revenues.
We currently have limited marketing, sales or distribution infrastructure. If we are unable to adequately develop sales, marketing 
and distribution capabilities on our own or through collaborations, we will not be successful in commercializing our antibody 
candidates.
While we have hired a Chief Commercial Officer and certain personnel to support market access and supply chain, we currently have 
only limited marketing, and distribution capabilities, and no sales force, because we have exclusively licensed PTx to commercialize 
our single approved product, BIZENGRI® in the U.S. for the labeled indications in NRG1+ pancreatic adenocarcinoma and NSCLC 
cancer, and all of our other antibody candidates are still in clinical or pre-clinical development. Apart from BIZENGRI®, if any of our 
antibody candidates are approved, we intend either to establish a sales and marketing organization with technical expertise and 
supporting distribution capabilities to commercialize our antibody candidates, or to outsource this function to a third party. Either of 
these options would be expensive and time consuming. These costs may be incurred in advance of any approval of our antibody 
candidates. In addition, we may not be able to hire a sales force that is sufficient in size or has adequate expertise in the medical 
markets that we intend to target. Any failure, delay or inadequacy in the development of our internal sales, marketing and distribution 
capabilities would adversely impact the commercialization of any approved products.
Irrespective of our entry into a license agreement with PTx with respect to marketing, sales or distribution of BIZENGRI®, our 
product revenue may be lower than if we directly marketed or sold any approved products. In addition, any revenue we receive will 
depend in whole or in part upon the efforts of this third-party licensee, which may not be successful and are generally not within our 
control. With respect to our other antibody candidates, if we are unable to enter into these arrangements on acceptable terms or at all, 
we may not be able to successfully commercialize any approved products. If we are not successful in commercializing any approved 

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products, either on our own or through collaborations with one or more third parties, our future product revenue will suffer and we 
may incur significant additional losses.
We have never commercialized an antibody candidate before and may lack the necessary expertise, personnel and resources to 
successfully commercialize our products on our own or together with suitable collaborators.
We have never commercialized an antibody candidate. While we have hired a Chief Commercial Officer and certain personnel to 
support market access and supply chain, we currently have only limited marketing or distribution capabilities, and no sales force. To 
achieve commercial success for our antibody candidates, if approved, which we may license to others, we will rely on the assistance 
and guidance of those collaborators. For antibody candidates for which we retain commercialization rights, we will have to develop 
our own sales, marketing and supply organization or outsource these activities to a third party. Outside consultants may be relied upon 
to provide advice on commercialization strategies, which may fail to deliver or provide effective guidance to maximize any 
commercial opportunity, if any, that may arise from our antibody candidates.
Factors that may affect our ability to commercialize our antibody candidates on our own include obtaining effective advice from 
consultants on commercialization strategy, recruiting and retaining adequate numbers of effective sales and marketing personnel, 
having adequate numbers of physicians decide to prescribe our antibody candidates and other unforeseen costs associated with 
creating an independent sales and marketing organization. Developing a sales and marketing organization will be expensive and time-
consuming and could delay the launch of our antibody candidates, if approved. We may not be able to build an effective sales and 
marketing organization. If we are unable to build our own distribution and marketing capabilities or to find suitable partners for the 
commercialization of our antibody candidates, we may not generate revenues from them or be able to reach or sustain profitability.
Our antibody candidates for which we intend to seek approval as biologic products may face competition sooner than anticipated.
The ACA includes a subtitle called the Biologics Price Competition and Innovation Act of 2009 (BPCIA) which created an 
abbreviated approval pathway for biological products that are biosimilar to or interchangeable with an FDA-licensed reference 
biological product. Under the BPCIA, an application for a biosimilar product may not be submitted to the FDA until four years 
following the date that the reference product was first approved by the FDA. In addition, the approval of a biosimilar product may not 
be made effective by the FDA until 12 years from the date on which the reference product was first approved. During this 12-year 
period of exclusivity, another company may still market a competing version of the reference product if the FDA approves a full BLA 
for the competing product containing the sponsor’s own pre-clinical data and data from adequate and well-controlled clinical trials to 
demonstrate the safety, purity and potency of their product. 
We believe that zenocutuzumab does qualify, and any of our antibody candidates approved as a biological product under a BLA 
should qualify for the 12-year period of exclusivity. However, there is a risk that this exclusivity could be shortened due to 
congressional action or otherwise. Moreover, the extent to which a biosimilar, once approved, will be substituted for any one of our 
reference products in a way that is similar to traditional generic substitution for non-biological products is not yet clear, and will 
depend on a number of marketplace and regulatory factors that are still developing.
Jurisdictions in addition to the United States have established abbreviated pathways for regulatory approval of biological products that 
are biosimilar to earlier approved reference products. For example, the EU has had an established regulatory pathway for biosimilars 
since 2006.
The increased likelihood of biosimilar competition has increased the risk of loss of innovators’ market exclusivity. Due to this risk, 
and uncertainties regarding patent protection, if our antibody candidates are approved for marketing, it is not possible to predict the 
length of market exclusivity for any particular product with certainty based solely on the expiration of the relevant patent(s) or the 
current forms of regulatory exclusivity. It is also not possible to predict changes in United States regulatory law that might reduce 
biological product regulatory exclusivity. The loss of market exclusivity for a product would likely materially and negatively affect 
revenues and we may not generate adequate or sufficient revenues from them or be able to reach or sustain profitability.
Risks Related to Our Dependence on Third Parties
We rely, and expect to continue to rely, on third parties, including independent clinical investigators and CROs, to conduct our 
pre-clinical studies and clinical trials. If these third parties do not successfully carry out their contractual duties or meet expected 
deadlines, we may not be able to obtain regulatory approval for or commercialize our antibody candidates and our business could 
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We have relied upon and plan to continue to rely upon third parties, including independent clinical investigators and third-party CROs, 
to conduct our pre-clinical studies and clinical trials and to monitor and manage data for our ongoing pre-clinical and clinical 
programs. We rely on these parties for execution of our pre-clinical studies and clinical trials, and control only certain aspects of their 
activities. Nevertheless, we are responsible for ensuring that each of our studies and trials is conducted in accordance with the 
applicable protocol, legal, regulatory and scientific standards, and our reliance on these third parties does not relieve us of our 
regulatory responsibilities. We and our third-party contractors and CROs are required to comply with GCP requirements, which are 
regulations and guidelines enforced by the FDA, the competent authorities of the member states of the EEA, and comparable foreign 
regulatory authorities for all of our antibody candidates in clinical development. Regulatory authorities enforce these GCPs through 
periodic inspections of trial sponsors, principal investigators and trial sites. If we or any of our CROs fail to comply with applicable 
GCPs, the clinical data generated in our clinical trials may be deemed unreliable and the FDA, the EMA or comparable foreign 
regulatory authorities, who may require us to perform additional clinical trials before approving our marketing applications. We 
cannot assure you that upon inspection by a given regulatory authority, such regulatory authority will determine that any of our 
clinical trials comply with GCP regulations. In addition, our clinical trials must be conducted with the antibody candidate produced 
under cGMP or similar foreign regulations. Our failure to comply with these regulations may require us to repeat clinical trials, which 
would delay the regulatory approval process.
Further, these investigators and CROs are not our employees and we will not be able to control, other than by contract, the amount of 
resources, including time, which they devote to our antibody candidates and clinical trials. If independent investigators or CROs fail to 
devote sufficient resources to the development of our antibody candidates, or if their performance is substandard, it may delay or 
compromise the prospects for approval and commercialization of any antibody candidates that we develop. In addition, the use of 
third-party service providers may require us to disclose our proprietary information to these parties, which could increase the risk that 
this information will be misappropriated.
Our CROs have the right to terminate their agreements with us in the event of an uncured material breach. In addition, some of our 
CROs have an ability to terminate their respective agreements with us if it can be reasonably demonstrated that the safety of the 
subjects participating in our clinical trials warrants such termination, if we make a general assignment for the benefit of our creditors 
or if we are liquidated.
If any of our relationships with these third-party CROs terminate, we may not be able to enter into arrangements with alternative 
CROs or to do so on commercially reasonable terms. If CROs do not successfully carry out their contractual duties or obligations or 
meet expected deadlines, if they need to be replaced or if the quality or accuracy of the clinical data they obtain is compromised due to 
the failure to adhere to our clinical protocols, regulatory requirements or for other reasons, our clinical trials may be extended, delayed 
or terminated and we may not be able to obtain regulatory approval for or successfully commercialize our antibody candidates. As a 
result, our results of operations and the commercial prospects for our antibody candidates would be harmed, our costs could increase 
and our ability to generate revenues could be delayed.
Switching or adding additional CROs involves additional cost and requires management time and focus. In addition, there is a natural 
transition period when a new CRO commences work. As a result, delays occur, which can materially impact our ability to meet our 
desired clinical development timelines. Additionally, CROs may lack the capacity to absorb higher workloads or take on additional 
capacity to support our needs. Though we carefully manage our relationships with our CROs, there can be no assurance that we will 
not encounter similar challenges or delays in the future or that these delays or challenges will not have a material adverse impact on 
our business, financial condition and prospects. 
The collaboration and license agreement, or the Incyte Collaboration Agreement, with Incyte Corporation (Incyte) is important to 
our business. If suitable monospecific or bispecific antibody candidates are not identified for further development and 
commercialization activities under the Incyte Collaboration Agreement, or if we or Incyte fail to adequately perform under the 
Incyte Collaboration Agreement, or if we or Incyte terminate the Incyte Collaboration Agreement, the development and 
commercialization of our antibody candidates would be delayed or terminated and our business would be adversely affected.
The Incyte Collaboration Agreement may be terminated:
•
in its entirety or on a program-by-program basis by Incyte for convenience;
•
in its entirety or on a program-by-program basis by either party due to a material breach of the Incyte Collaboration 
Agreement, or any one or more programs under the Incyte Collaboration Agreement, as applicable; and
•
on a program-by-program basis (but not in its entirety), by either party if the other party challenges the terminating 
party’s patents for such program, and such challenge is not withdrawn within 30 days.

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If the Incyte Collaboration Agreement is terminated with respect to one or more programs, all rights in the terminated programs revert 
to us, subject to payment to Incyte of a reverse royalty of up to 4% on sales of future products, depending on the stage of development 
as of the date of termination, if we elect to pursue development and commercialization of monospecific or bispecific antibody 
candidates arising from the terminated programs.
Termination of the Incyte Collaboration Agreement could cause significant delays in our antibody candidate development and 
commercialization efforts, which could prevent us from commercializing our antibody candidates without first expanding our internal 
capabilities or entering into another agreement with a third party. Any suitable alternative collaboration or license agreement would 
take considerable time to negotiate and could also be on less favorable terms to us. In addition, under the Incyte Collaboration 
Agreement, Incyte agreed to conduct certain clinical development activities. If the Incyte Collaboration Agreement were to be 
terminated, and whether or not we identify another suitable collaborator, we may need to seek additional financing to support the 
research and development of any terminated antibody candidates so that we may continue development activities, or we may be forced 
to discontinue development of terminated antibody candidates, each of which could have a material adverse effect on our business.
Under the Incyte Collaboration Agreement, we are dependent upon Incyte to successfully develop and commercialize any antibody 
candidates that are identified for further development under the Incyte Collaboration Agreement. With the exception of those 
programs where we retain certain co-development rights, we have limited ability to influence or control Incyte’s development and 
commercialization activities or the resources it allocates to development of product candidates identified under the Incyte 
Collaboration Agreement. Our interests and Incyte’s interests may differ or conflict from time to time, or we may disagree with 
Incyte’s level of effort or resource allocation. Incyte may internally prioritize programs under development within the collaboration 
differently than we would, or it may not allocate sufficient resources to effectively or optimally develop or commercialize antibody 
candidates arising from such programs. If these events were to occur, our ability to receive revenue from the commercialization of 
products arising from such programs would be reduced, and our business would be adversely affected.
The collaboration and license agreement with Eli Lilly, or the Lilly Collaboration Agreement is important to our business. If 
suitable monospecific or bispecific antibody candidates are not identified for further development and commercialization activities 
under the Lilly Collaboration Agreement, or if we or Eli Lilly fail to adequately perform under the Lilly Collaboration Agreement, 
or if we or Eli Lilly terminate the Lilly Collaboration Agreement, the development and commercialization of our antibody 
candidates would be delayed or terminated and our business would be adversely affected.
The Lilly Collaboration Agreement may be terminated:
•
in its entirety or on a program-by-program basis by Eli Lilly for convenience;
•
on a product-by-product basis (but not in its entirety), by Merus if Lilly challenges the Merus patents for such product 
and
•
in its entirety or on a program-by-program basis by either party due to a material breach of the Lilly Collaboration 
Agreement, or any one or more programs under the Lilly Collaboration Agreement, as applicable.
If the Lilly Collaboration Agreement is terminated with respect to one or more programs, depending on the stage of development, 
certain rights in the terminated programs revert to us.
Termination of the Lilly Collaboration Agreement could cause significant delays in our antibody candidate development and 
commercialization efforts, which could prevent us from commercializing our antibody candidates without first expanding our internal 
capabilities or entering into another agreement with a third party. Any suitable alternative collaboration or license agreement would 
take considerable time to negotiate and could also be on less favorable terms to us. In addition, under the Lilly Collaboration 
Agreement, Eli Lilly agreed to conduct certain pre-clinical and clinical development activities. If the Lilly Collaboration Agreement 
were to be terminated, and whether or not we identify another suitable collaborator, we may need to seek additional financing to 
support the research and development of any terminated antibody candidates so that we may continue development activities, or we 
may be forced to discontinue development of terminated antibody candidates, each of which could have a material adverse effect on 
our business.
Under the Lilly Collaboration Agreement, we are dependent upon Eli Lilly to successfully develop and commercialize any antibody 
candidates that are identified for further development under the Lilly Collaboration Agreement. We have limited ability to influence or 
control Eli Lilly’s development and commercialization activities or the resources it allocates to development of product candidates 
identified under the Lilly Collaboration Agreement. Our interests and Eli Lilly’s interests may differ or conflict from time to time, or 
we may disagree with Eli Lilly’s level of effort or resource allocation. Eli Lilly may internally prioritize programs under development 

79
within the collaboration differently than we would, or it may not allocate sufficient resources to effectively or optimally develop or 
commercialize antibody candidates arising from such programs. If these events were to occur, our ability to receive revenue from the 
commercialization of products arising from such programs would be reduced, and our business would be adversely affected.
The collaboration, option and license agreement, or the Gilead Collaboration Agreement, with Gilead is important to our business. 
If suitable trispecific antibody candidates are not identified for further development and commercialization activities under the 
Gilead Collaboration Agreement, or if we or Gilead fail to adequately perform under the Gilead Collaboration Agreement, or if we 
or Gilead terminate the Gilead Collaboration Agreement, the development and commercialization of our trispecific antibody 
candidates would be delayed or terminated and our business would be adversely affected. 
The Gilead Collaboration Agreement may be terminated: 
• 
in its entirety or on a program-by-program basis by Gilead for convenience or for futility; 
•
on a product-by-product basis (but not in its entirety), by Merus if Gilead challenges the Merus patents for such 
product; and 
•
in its entirety or on a program-by-program basis by either party due to a material breach of the Gilead Collaboration 
Agreement, or any one or more programs under the Gilead Collaboration Agreement, as applicable. 
If the Gilead Collaboration Agreement is terminated with respect to one or more programs, depending on the stage of development, 
certain rights in the terminated programs revert to us. Termination of the Gilead Collaboration Agreement could cause significant 
delays in our antibody candidate development and commercialization efforts, which could prevent us from commercializing our 
Triclonics® antibody candidates without first expanding our internal capabilities or entering into another agreement with a third party. 
Any suitable alternative collaboration or license agreement would take considerable time to negotiate and could also be on less 
favorable terms to us. In addition, under the Gilead Collaboration Agreement, Gilead agreed to conduct certain pre-clinical and 
clinical development activities. If the Gilead Collaboration Agreement were to be terminated, and whether or not we identify another 
suitable collaborator, we may need to seek additional financing to support the research and development of any terminated antibody 
candidates so that we may continue development activities, or we may be forced to discontinue development of terminated antibody 
candidates, each of which could have a material adverse effect on our business. Under the Gilead Collaboration Agreement, we are 
dependent upon Gilead to successfully develop and commercialize any Triclonics® antibody candidates that are identified for further 
development under the Gilead Collaboration Agreement. We have limited ability to influence or control Gilead’s development and 
commercialization activities or the resources it allocates to development of product candidates identified under the Gilead 
Collaboration Agreement. Our interests and Gilead’s interests may differ or conflict from time to time, or we may disagree with 
Gilead’s level of effort or resource allocation. Gilead may internally prioritize programs under development within the collaboration 
differently than we would, or it may not allocate sufficient resources to effectively or optimally develop or commercialize antibody 
candidates arising from such programs. If these events were to occur, our ability to receive revenue from the commercialization of 
products arising from such programs would be reduced, and our business would be adversely affected.
The collaboration and license agreement with Betta Pharma, and the research and license agreements with Ono are important to 
our business. If our Biclonics® antibodies licensed in these collaboration and license agreements fail to advance or experience 
unacceptable safety or efficacy results if clinically developed, this could adversely impact the reputation of our platform and our 
ability to engage in future collaborations.
If our collaboration and license agreement with Betta Pharma or our research and license agreements with Ono are terminated with 
respect to one or more programs, or the pre-clinical assets associated with the Ono license agreements fail to advance into the clinic, 
or experience negative results with respect to safety, efficacy, manufacturability, or other features of research and development, this 
could adversely affect the reputation of our Biclonics® technology platform and our ability to engage in future collaborations or 
licensing agreements. While we have certain contractual provisions in place in our collaboration and license agreement with Betta 
Pharma that permit us to supervise its development efforts for MCLA-129, for which it has development and product rights in China, 
we cannot guarantee that this clinical antibody candidate will be developed in China in accordance with our standards as applied to 
our wholly owned programs or in a manner suitable for ex-China development or in a manner that does not detract from our 
development of MCLA-129 outside of China. Ono is currently clinically developing at least two antibody programs generated by us 
under a license agreement with Merus through use of our proprietary Biclonics® platform. To the extent these assets do not 
successfully advance through clinical development, this may impair our ability to leverage our platform in future license agreements 
to further expand the use of our platform and generate future revenue. Should the Betta Pharma collaboration or Ono license 
agreements fail or be terminated, any suitable alternative collaboration or license agreement would take considerable time to negotiate, 
if at all, and could also be on less favorable terms to us. If these agreements were to be terminated, and whether or not we identify a 
suitable alternative collaborator, we may need to seek additional financing to support the research and development of any terminated 
antibody candidates so that we may continue development activities, or we may be forced to discontinue development of terminated 

80
antibody candidates, each of which could, depending on the stage of development and investment, have a material adverse effect on 
our business. 
The license agreement with PTx is important to our business. If BIZENGRI® (zenocutuzumab-zbco) exclusively licensed to PTx 
for commercialization in the United States for NRG1+ cancer fails to generate revenue, this could adversely impact the reputation 
of our business and our ability to engage in future commercialization agreements.
If our license agreement with PTx fails to generate revenue, or experiences negative results with maintenance of BIZENGRI®'s 
accelerated approval, conversion to full approval, or experiences a failed transition with respect to the CRO and CMDO that we have 
worked with for the development of BIZENGRI®,  this could adversely affect the reputation of our Company, our ability to generate 
revenue from this license and our ability to engage in future collaborations or commercial licensing agreements. While we have 
certain contractual provisions in place in our license agreement with PTx that require PTx to exercise diligence in the 
commercialization of BIZENGRI® and  permit us to supervise its efforts, we cannot guarantee that this will lead to significant 
revenue or performed in accordance with our standards as applied to our wholly owned programs. Should the PTx license agreement 
fail or be terminated, any suitable alternative license agreement would take considerable time to negotiate, if at all, and could also be 
on less favorable terms to us, and our own efforts to commercialize BIZENGRI® post-termination may be hampered by a transition of 
the asset back to Merus. If this agreement were to be terminated, and whether or not we identify a suitable alternative licensee, we 
may need to seek additional financing to support the commercialization of BIZENGRI®, so that we may continue marketing 
activities, or we may be forced to discontinue commercialization, each of which could have a material adverse effect on our business. 
If we fail to enter into new strategic relationships our business, financial condition, commercialization prospects and results of 
operations may be materially adversely affected.
Our product development programs and the potential commercialization of our antibody candidates will require substantial additional 
cash to fund expenses. Therefore, for some of our antibody candidates and with respect to our Triclonics® technology platform, we 
may decide to enter into new collaborations with pharmaceutical or biotechnology companies for the development and potential 
commercialization of those bispecific and trispecific antibody candidates. For instance, we have license and collaboration agreements 
with Ono, Incyte, Eli Lilly and Betta Pharma, under which we have licensed certain development and commercialization rights of 
certain of our monospecific or bispecific antibody candidates. Further, we have a license agreement with PTx for the 
commercialization of BIZENGRI® in the U.S. in the field of NRG1+ cancer.
We face significant competition in seeking appropriate collaborators. Collaborations are complex and time-consuming to negotiate 
and document. We may also be restricted under existing and future collaboration agreements from entering into agreements on certain 
terms with other potential collaborators. We may not be able to negotiate collaborations on acceptable terms, or at all. If that were to 
occur, we may have to curtail the development of a particular bispecific or trispecific antibody 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 
our sales or marketing activities, or increase our expenditures and undertake development or commercialization activities at our own 
expense. If we elect to increase our expenditures to fund development or commercialization activities on our own, we may need to 
obtain additional capital, which may not be available to us on acceptable terms or at all. If we do not have sufficient funds, we will not 
be able to bring our antibody candidates to market, further research and develop new trispecific antibody candidates, enhance our 
Biclonics® and Triclonics® technology platforms and generate product revenue. If we do enter into a new collaboration agreement, 
we could be subject to the following risks, each of which may materially harm our business, commercialization prospects and 
financial condition:
•
we may not be able to control the amount and timing of resources that the collaborator devotes to the product 
development program;
•
the collaborator may experience financial difficulties;
•
we may be required to relinquish important rights such as marketing, distribution and intellectual property rights;
•
a collaborator may experience technical, clinical, intellectual property, manufacturing or other setbacks in the research or 
development of a product program arising from our collaboration adversely affecting the financial return of our 
collaboration or the reputation of our technology platform; 
•
a collaborator could move forward with a competing product developed either independently or in collaboration with 
third parties, including our competitors; or

81
•
business combinations or significant changes in a collaborator’s business strategy may adversely affect our willingness 
to complete our obligations under any arrangement.
We currently rely on third-party suppliers and other third parties for production of our antibody candidates and our dependence on 
these third parties may impair the advancement of our research and development programs and the development of our antibody 
candidates. Moreover, we intend to rely on third parties to produce commercial supplies of any approved antibody candidate and 
our commercialization of any of our antibody candidates could be stopped, delayed or made less profitable if those third parties fail 
to obtain approval of the FDA or comparable foreign regulatory authorities following inspection of their facilities and procedures 
to manufacture our antibody candidates and products, fail to provide us with sufficient quantities of antibody product or fail to do 
so at acceptable timing, quality levels or prices or fail to otherwise complete their duties in compliance with their obligations to us 
or other parties.
We rely on and expect to continue to rely on third-party contract manufacturing organizations (CMOs) for the supply of cGMP-grade 
clinical trial materials and commercial quantities of our antibody candidates and products, if approved. Reliance on third-party 
providers may expose us to more risk than if we were to manufacture antibody candidates ourselves. The facilities used by our CMOs 
to manufacture our antibody candidates must be approved by the FDA foreign regulatory authorities pursuant to inspections that will 
be conducted after we submit our BLA to the FDA, or similar applications to foreign regulatory authorities. We have limited control 
over the manufacturing process of, and beyond contractual terms, we are completely dependent on our CMOs for compliance with 
cGMP or similar foreign requirements for the manufacture of our antibody candidates. If our CMOs cannot successfully manufacture 
material that conforms to our specifications and the strict regulatory requirements of the FDA or comparable foreign regulatory 
authorities, or are unable to do so in a timely manner, they will not be able to secure and/or maintain regulatory approval for their 
manufacturing facilities or may result in delay of our ability to obtain marketing authorization, if any, of our antibody candidates. In 
addition, we have limited control over the ability of our CMOs to maintain adequate quality control, quality assurance and qualified 
personnel. If the FDA or a comparable foreign regulatory authority does not approve these facilities for the manufacture of our 
antibody candidates or if it withdraws any such approval in the future, we may need to find alternative manufacturing facilities, which 
would significantly impact our ability to develop, obtain regulatory approval for or market our antibody candidates, if approved. In 
addition, any failure to achieve and maintain compliance with these laws, regulations and standards could subject us to the risk that we 
may have to suspend the manufacturing of our antibody candidates or that obtained approvals could be revoked, which would 
adversely affect our business and reputation. Furthermore, third-party providers may breach existing agreements they have with us 
because of factors beyond our control. They may also terminate or refuse to renew their agreement because of their own financial 
difficulties or business priorities, at a time that is costly or otherwise inconvenient for us. If we were unable to find an adequate 
replacement or another acceptable solution in time, our clinical trials could be delayed or our commercial activities could be harmed. 
In addition, the fact that we are dependent on our collaborators, our CMOs and other third parties for the manufacture, filling, storage 
and distribution of our antibody candidates means that we are subject to the risk that the products may have manufacturing defects that 
we have limited ability to prevent or control. The sale of products containing such defects could adversely affect our business, 
financial condition and results of operations.
We rely on our CMOs to purchase from third-party suppliers the materials necessary to produce our antibody candidates for our 
clinical trials, and will rely on our existing and future collaborators to purchase from third-party suppliers the materials necessary to 
develop and produce our antibody candidates for future clinical trials and, upon approval, our products for commercialization. There 
are a limited number of suppliers for raw materials that we use to manufacture our antibody candidates and there may be a need to 
assess alternate suppliers to prevent a possible disruption of the manufacture of the materials necessary to produce our antibody 
candidates for our clinical trials, and if approved, ultimately for commercial sale. Apart from contractual measures, we do not have 
any control over the process or timing of the acquisition of these raw materials by our manufacturers or manufacturers paid by our 
collaborators. Moreover, we currently do not have any agreements for the commercial production of these raw materials. Although we 
generally do not begin a clinical trial unless we believe we have a sufficient supply of an antibody candidate to complete the clinical 
trial or have secured resupply capacity, any significant delay in the supply of an antibody candidate, or the raw material components 
thereof, for a planned or an ongoing clinical trial due to the need to replace a third-party manufacturer could considerably delay 
completion of our clinical trials, product testing and potential regulatory approval of our antibody candidates. 
In addition, the manufacturing of our novel antibody candidates is expensive and time-consuming, and generally requires more 
complex processes than those associated with small-molecule drugs. If we are successful in obtaining regulatory approval for any of 
our antibody candidates, including zenocutuzumab, we might have limited quantities of such antibody candidates available to us in 
connection with a potential commercial launch, and these supplies may be further limited by our ongoing clinical development 
activities. If our manufacturers, collaborators or we are unable to purchase or produce sufficient quantities of raw materials or of our 
antibody candidates after regulatory approval has been obtained for our antibody candidates, the commercial launch of our antibody 

82
candidates could be delayed or there could be a shortage in supply, which in either case, would impair our ability to generate revenues 
from the sale of our antibody candidates.  
We rely on our manufacturers and other subcontractors to comply with and respect the proprietary rights of others in conducting their 
contractual obligations for us. If our manufacturers or other subcontractors fail to acquire the proper licenses or otherwise infringe 
third party proprietary rights in the course of completing their contractual obligations to us, we may have to find alternative 
manufacturers or defend against claims of infringement, either of which would significantly impact our ability to develop, obtain 
regulatory approval for or market our antibody candidates, if approved.
Risks Related to Intellectual Property and Information Technology
We rely on patents and other intellectual property rights to protect our technology, including antibody candidates and our 
Biclonics® technology platform and Triclonics® technology platform, the enforcement, defense and maintenance of which may be 
challenging and costly. Failure to enforce or protect these rights adequately could harm our ability to compete and impair our 
business.
Our commercial success depends in part on obtaining and maintaining patents and other forms of intellectual property rights for our 
Biclonics® technology platform, Triclonics® technology platform, our common light chain transgenic technology, our dimerization 
technology, our heavy chain variable regions and binding domains that bind particular antigens, our monospecific antibodies, 
bispecific antibody, trispecific antibody and antibody pre-clinical and clinical candidates, products, their format and methods and host 
cells used to produce, screen, manufacture and purify those pre-clinical antibody and antibody clinical candidates, the methods for 
treating patients using those candidates, among other aspects of our technology or on licensing-in such rights. Failure to protect or to 
obtain, maintain or extend adequate patent and other intellectual property rights could materially adversely affect our ability to 
develop and market our platform technologies, and antibody candidates.
The patent prosecution process is expensive and time-consuming, and we and our current or future licensors, licensees or collaborators 
may not be able to prepare, file and prosecute all necessary or desirable patent applications at a reasonable cost or in a timely manner. 
It is also possible that we or our licensors, licensees or collaborators will fail to identify patentable aspects of inventions made in the 
course of development and commercialization activities before it is too late to obtain patent protection on them. Further, the issuance, 
scope, validity, enforceability and commercial value of our and our current or future licensors’, licensees’ or collaborators’ patent 
rights are highly uncertain. Our and our licensors’ pending and future patent applications may not result in patents being issued which 
protect our technology or products, in whole or in part, or which effectively prevent others from commercializing competitive 
technologies and products. The patent examination process may require us or our licensors, licensees or collaborators to narrow the 
scope of the claims of our or our licensors’, licensees’ or collaborators’ pending and future patent applications, which may limit the 
scope of patent protection that may be obtained. We cannot assure you that all of the potentially relevant prior art relating to our 
patents and patent applications has been found. If such prior art exists, it can invalidate a patent or prevent a patent from issuing from 
a pending patent application. Even if patents do successfully issue, or have issued and even if such patents cover our Biclonics® 
technology platform, Triclonics® technology platform, our common light chain transgenic technology, our dimerization technology 
our heavy chain variable regions and binding domains that bind particular antigens, our monospecific antibodies, bispecific antibody, 
trispecific antibody and antibody pre-clinical and clinical candidates, products, their format and methods and host cells used to 
produce, screen, manufacture and purify those pre-clinical antibody and antibody clinical candidates, the methods for treating patients 
using those candidates, and other technologies, third parties may initiate opposition, interference, re-examination, post-grant review, 
inter partes review, nullification or derivation action in court or before patent offices, or similar proceedings challenging the validity, 
enforceability or scope of such patents, which may result in the patent claims being narrowed or invalidated. Our and our licensors’, 
licensees’ or collaborators’ patent applications cannot be enforced against third parties practicing the technology claimed in such 
applications unless and until a patent issues from such applications, and then only to the extent the issued claims cover the technology 
in the relevant jurisdiction.
Because patent applications are confidential for a period of time after filing, and some remain so until issued, we cannot be certain that 
we or our licensors were the first to file any patent application related to our technology, including our antibody candidates. 
Furthermore, if third parties have filed such patent applications on or before March 15, 2013, an interference proceeding can be 
initiated by such third parties to determine who was the first to invent any of the subject matter covered by the patent claims of our 
applications. If third parties have filed such applications after March 15, 2013, a derivation proceeding can be initiated by such third 
parties to determine whether our invention was derived from theirs.

83
Issued patents covering one or more of our products or the Biclonics® technology or Triclonics® technology platforms could be 
found invalid or unenforceable if challenged in court.
To protect our competitive position, we may from time to time need to resort to litigation to enforce or defend any patents or other 
intellectual property rights owned by or licensed to us, or to determine or challenge the scope or validity of patents or other intellectual 
property rights of third parties. As enforcement of intellectual property rights is difficult, unpredictable and expensive, we may fail in 
enforcing our rights—in which case our competitors may be permitted to use our technology without being enjoined, required to pay 
us any license fees, or compensate us for lost profits or reasonable royalty. In addition, litigation involving our patents carries the risk 
that one or more of our patents will be held invalid (in whole or in part, on a claim-by-claim basis) or held unenforceable. Such an 
adverse court ruling could allow third parties to commercialize technology covered by our patents we seek to enforce, such as those 
covering our antibody candidates or methods, our Biclonics® technology and Triclonics® technology platforms, our common light 
chain transgenic technology, or our dimerization technology, among other technologies, and then compete directly with us, without 
payment to us.
If we were to initiate legal proceedings against a third party to enforce a patent covering our technology, one of our products or 
methods, the defendant could counterclaim that our patent is invalid and/or unenforceable. In patent litigation in the United States or 
in certain jurisdictions in Europe, defendant counterclaims alleging invalidity and/or unenforceability are commonplace. Grounds for a 
validity challenge could be an alleged failure to meet any of several statutory requirements for patentability, for example, lack of 
utility, novelty, obviousness, non-enablement or lack of written description or as constituting unpatentable subject matter. Grounds for 
an unenforceability assertion could be an allegation that someone substantively involved in prosecution of the patent withheld but-for 
material information from the U.S. Patent and Trademark Office (USPTO) or engaged in affirmatively egregious misconduct, during 
prosecution, with a specific intent to deceive the USPTO. The outcome following legal assertions of invalidity and unenforceability 
during patent litigation is unpredictable. With respect to the validity question, for example, we cannot be certain that there is no 
invalidating prior art, of which we and the patent examiner were unaware during prosecution. If a defendant were to prevail on a legal 
assertion of invalidity and/or unenforceability, we could lose at least part, and perhaps all, of the patent protection on one or more of 
our technologies, products, methods or certain aspects of our Biclonics® technology and Triclonics® technology platforms. Such a 
loss of patent protection could have a material adverse impact on our business. Patents and other intellectual property rights also will 
not protect our technology if competitors design around our protected technology without infringing our patents or other intellectual 
property rights.
Intellectual property rights of third parties could adversely affect our ability to commercialize our antibody candidates, such that 
we could be required to litigate or obtain licenses from third parties in order to develop or market our antibody candidates. Such 
litigation or licenses could be costly or not available on commercially reasonable terms or at all.
Our competitive position may suffer if patents issued to third parties or other third-party intellectual property rights cover our 
technology platforms, methods or candidates or elements thereof, our manufacture or uses relevant to our development, or other 
attributes of our antibody candidates or our Biclonics® technology platform or Triclonics® technology platform. In such cases, we 
may not be in a position to develop or commercialize products or antibody candidates unless we successfully pursue litigation, 
opposition, inter partes, or related post-grant proceedings to nullify or invalidate the third-party intellectual property right concerned, 
or enter into a license agreement with the intellectual property right holder, if available on commercially reasonable terms. In addition, 
we are aware of issued patents and/or pending patent applications held by third parties that could be alleged as covering some of our 
antibody candidates, irrespective of the merits. We believe that if such patents or patent applications (if issued as currently pending) 
were asserted against us, we would have counterclaims and defenses against such claims, including non-infringement, the affirmative 
defense of safe harbor designed to protect activity undertaken to obtain federal regulatory approval of a drug, including under 35 
U.S.C. § 271(e) and similar foreign exceptions to infringement, and defenses concerning patent invalidity and/or unenforceability. 
However, if such counterclaims and defenses were not successful and such patents were successfully asserted against us such that they 
are found to be valid and enforceable, and infringed, unless we obtain a license to such patents, which may not be available on 
commercially reasonable terms or at all, we could be prevented from continuing to develop or commercialize our technology. We 
could also be required to pay substantial damages. 
It is also possible that in our evaluation of third party intellectual property, we failed to identify relevant patents or applications. For 
example, U.S. applications filed before November 29, 2000 and certain U.S. applications filed after that date that will not be filed 
outside the United States remain confidential until patents issue. Patent applications in the United States and elsewhere are published 
approximately 18 months after the earliest filing for which priority is claimed, with such earliest filing date being commonly referred 
to as the priority date. Therefore, patent applications covering our products or platform technologies could have been filed by others 
without our knowledge. Furthermore, we operate in a highly competitive field, and given our limited resources, it is unreasonable to 
monitor all patent applications purporting to claim broad coverage in the areas in which we are active. Additionally, pending patent 

84
applications which have been published can, subject to certain limitations, be later amended in a manner that could cover our platform 
technologies, our methods, antibody candidates or the use of our bispecific and trispecific antibody candidates.
Third party intellectual property right holders, including our competitors, may actively bring infringement claims against us. The 
granting of orphan drug status in respect of any of our antibody candidates does not guarantee our freedom to operate and is separate 
from our risk of possible infringement of third parties’ intellectual property rights. We may not be able to successfully settle or 
otherwise resolve such potential infringement claims. If we are unable to successfully settle future claims on terms acceptable to us, 
we may be required to engage or continue costly, unpredictable and time-consuming litigation and may be prevented from or 
experience substantial delays in marketing any approved products.
If we fail in any such dispute, in addition to being forced to potentially pay damages, we or our licensees may be temporarily or 
permanently prohibited from commercializing any of our antibody candidates that are held to be infringing or be forced to redesign 
antibody candidates so that we no longer infringe the third-party intellectual property rights. Any of these events, even if we were 
ultimately to prevail, could require us to divert substantial financial and management resources that we would otherwise be able to 
devote to our business.
In addition, if the breadth or strength of protection provided by our or our present or future licensors’, collaborators’ or partners’ 
patents and patent applications is threatened, it could dissuade companies from collaborating with us to license, develop or 
commercialize current or future antibody candidates. Furthermore, because of the substantial amount of discovery required in 
connection with intellectual property litigation, there is a risk that some of our confidential information could be compromised by 
disclosure during this type of litigation.
Our ability to compete may be adversely affected if we are unsuccessful in defending against any claims by competitors or others 
that we are infringing upon their intellectual property rights.
The various markets in which we plan to operate are subject to frequent and extensive litigation regarding patents and other 
intellectual property rights. In addition, many companies in intellectual property-dependent industries, including those producing 
therapeutic candidates or products to treat and potentially cure cancer, have employed intellectual property litigation as a means to 
gain an advantage over their competitors. As a result, we may be required to defend against claims of intellectual property 
infringement that may be asserted by our competitors against us and, if the outcome of any such litigation is adverse to us, it may 
affect our ability to compete effectively.
Our involvement in litigation, and in any interferences, opposition, pre and post-grant administrative proceedings or other intellectual 
property proceedings inside and outside of the United States may divert management from focusing on business operations, could 
cause us to spend significant amounts of money and may have no guarantee of success. Any potential intellectual property litigation 
successfully adjudicated against us could also force us to do one or more of the following:
•
stop selling, incorporating, manufacturing or using our products, if approved, in the United States and/or other 
jurisdictions that are covered by the subject intellectual property;
•
obtain from a third party asserting its intellectual property rights, a license to sell or use the relevant technology, which 
license may not be available on reasonable terms, or at all, or may be non-exclusive thereby giving our competitors 
access to the same technologies licensed to us;
•
redesign those technologies, products or processes that use any allegedly infringing or misappropriated technology, 
which may result in significant cost or delay to us, or which redesign could be technically infeasible; or
•
pay damages, including the possibility of treble damages in a patent case if a court finds us to have willfully infringed 
certain intellectual property rights.
We are aware that significant number of patents and patent applications may exist relating to aspects of therapeutic antibody 
technologies filed by, and issued to, third parties.
We cannot assure you that we will ultimately prevail if any of this third-party intellectual property is asserted against us.
Intellectual property litigation could cause us to spend substantial resources and distract our personnel from their normal 
responsibilities.

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Where we are asserting our intellectual property against third parties, or defending against an allegation of infringement, 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, this could have a substantial adverse effect on the price of our common shares. Such 
litigation or proceedings and the legal costs associated with them, could substantially increase our operating losses and reduce our 
resources available for development activities. We may not have sufficient financial or other resources to adequately conduct such 
litigation or proceedings. Some of our competitors may be able to sustain the costs of such litigation or proceedings more effectively 
than we can because of their substantially greater financial resources. Uncertainties resulting from the initiation and continuation of 
patent litigation or other proceedings could have a material adverse effect on our ability to compete in the marketplace.
We may not be successful in obtaining or maintaining necessary rights to our antibody candidates through acquisitions and in-
licenses.
We currently have rights and own our intellectual property, including issued patents and pending patent applications, relating to and 
covering our Biclonics® technology and Triclonics® technology platforms, our common light chain transgenic technology, our 
dimerization technology, our heavy chain variable regions and binding domains that bind particular antigens, our monospecific 
antibodies, bispecific antibody, trispecific antibody and pre-clinical antibody and antibody clinical candidates, products, their format 
and methods and host cells used to produce, screen, manufacture and purify those pre-clinical antibody and antibody clinical 
candidates, the methods for treating patients using those candidates, among other aspects of our technology. Because our programs 
may require the use of proprietary rights held by third parties, the growth of our business may depend in part on our ability to acquire, 
in-license, maintain or use these proprietary rights. We may be unable to acquire or in-license any compositions, methods of use, 
processes, or other third-party intellectual property rights from third parties that we may identify as necessary for our antibody 
candidates. The licensing and acquisition of third-party intellectual property rights is a competitive area, and a number of more 
established companies are also pursuing strategies to license or acquire third-party intellectual property rights that we may consider 
attractive. These established companies may have a competitive advantage over us due to their size, cash resources, and greater 
clinical development and commercialization capabilities.
In addition, companies that perceive us to be a competitor may be unwilling to assign or license rights to us. We also may be unable to 
license or acquire third-party intellectual property rights on terms that would allow us to make an appropriate return on our 
investment. If we are unable to successfully obtain a license to third-party intellectual property rights necessary for the development of 
an antibody candidate or program, we may have to abandon development of that antibody candidate or program and our business and 
financial condition could suffer.
If our trademarks and trade names are not adequately protected, then we may not be able to build name recognition in our markets 
of interest and our business may be adversely affected.
We currently have trademark and service mark rights relating to and covering our Biclonics® technology and Triclonics® technology 
platforms, zenocutuzumab and other aspects of our company, its services and activities used in commerce.  Our registered or 
unregistered trademarks, trade names or service marks may be challenged including during prosecution or through opposition 
proceedings, infringed, circumvented or declared generic or determined to be infringing on other marks. We may not be able to protect 
our rights to these trademarks, trade names, and service marks, which we need to build name recognition by potential collaborators, 
partners or customers in our markets of interest. Over the long term, if we are unable to establish name recognition based on our 
trademarks, trade names and service marks then we may not be able to compete effectively and our business may be adversely 
affected. If other entities use trademarks, trade names or service marks similar to ours in different jurisdictions, or have senior rights to 
ours, or prevail in any opposition proceedings, it could interfere with our use of our current trademarks, trade names or service marks 
throughout the world.
If we do not obtain protection under the Hatch-Waxman Amendments and similar non-U.S. legislation for extending the term of 
patents covering each of our antibody candidates, our business may be materially harmed.
Patents typically have a limited lifespan. In the United States, if all maintenance fees are timely paid, the natural expiration of a patent 
is generally 20 years from its earliest U.S. non-provisional filing date, not including potential patent term extensions or adjustments 
that may be available in the U.S., and under comparable laws applicable outside the U.S., where certain conditions are met. Various 
extensions may be available, but the life of a patent, and the protection it affords, is limited. Even if patents covering our antibody 
candidates are obtained, once the patent life has expired for a candidate, we may be open to competition from competitive 
medications, including biosimilar or generic medications. Given the amount of time required for the development, testing and 

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regulatory review of new antibody candidates, patents protecting such candidates might expire before or shortly after such candidates 
are commercialized. As a result, our owned and licensed patent portfolio may not provide us with sufficient rights to exclude others 
from commercializing products similar or identical to ours, causing our revenue from applicable products to be reduced, possibly 
materially, and potentially harming our ability to recover our investment in such product or obtain a reasonable return on that 
investment.
Depending upon the timing, duration and conditions of FDA marketing approval of our antibody candidates, one or more of our U.S. 
patents may be eligible for limited patent term extension under the Drug Price Competition and Patent Term Restoration Act of 1984, 
referred to as the Hatch-Waxman Amendments, and similar legislation in the EU. The Hatch-Waxman Amendments permit a patent 
term extension of up to five years for a patent covering an approved product as compensation for effective patent term lost during 
product development and the FDA regulatory review process. However, we may not receive an extension if we fail to apply within 
applicable deadlines, fail to apply prior to expiration of relevant patents or otherwise fail to satisfy applicable requirements. Moreover, 
the length of the extension could be less than we request. If we are unable to obtain patent term extension or the term of any such 
extension is less than we request, the period during which we can enforce our patent rights for that product will be shortened and our 
competitors may obtain approval to market competing products sooner. As a result, our revenue from applicable products could be 
reduced, possibly materially.
We enjoy only limited geographical protection with respect to certain patents and may face difficulties in certain jurisdictions, 
which may diminish the value of intellectual property rights in those jurisdictions.
We generally file our first patent application (i.e., priority filing) in the Netherlands. International applications under the Patent 
Cooperation Treaty (PCT) are usually filed within 12 months after the priority filing, where we pursue patent applications in the U.S., 
across the E.U., and other PCT participating jurisdictions, as based on the PCT filing, national and regional patent applications may be 
filed in additional jurisdictions where we believe our antibody candidates may be marketed or manufactured or our platform 
technologies may be utilized. We have so far not filed for patent protection in all national and regional jurisdictions where such 
protection may be available. In addition, we may decide to abandon national and regional patent applications before grant. Finally, the 
grant proceeding of each national/regional patent is an independent proceeding which may lead to situations in which applications 
might in some jurisdictions be refused by the relevant patent offices, while granted by others. It is also quite common that depending 
on the country, the scope of patent protection may vary for the same antibody candidate and/or technology.
Competitors may use our and our existing or future licensors’, collaborators’ or partners’ technologies in jurisdictions where we have 
not obtained patent protection to develop their own products and, further, may export otherwise infringing products to territories 
where we and our existing or future licensors, collaborators or partners have patent protection, but enforcement is not as strong as that 
in the United States. These products may compete with our antibody candidates or our platform technologies, and our and our existing 
or future licensors’, collaborators’ or partners’ patents or other intellectual property rights may not be effective or sufficient to prevent 
them from competing.
The laws of some jurisdictions do not protect intellectual property rights to the same extent as the laws in the United States and the 
EU, and many companies have encountered significant difficulties in protecting and defending such rights in such jurisdictions. If we 
or our existing or future licensors, collaborators or partners encounter difficulties in protecting, or are otherwise precluded from 
effectively protecting, the intellectual property rights important for our business in such jurisdictions, the value of these rights may be 
diminished and we may face additional competition from others in those jurisdictions.
Some countries have compulsory licensing laws under which a patent owner may be compelled to grant licenses to third parties. In 
addition, some countries limit the enforceability of patents against government agencies or government contractors. In these countries, 
the patent owner may have limited remedies, which could materially diminish the value of such patent. If we or any of our existing or 
future licensors, collaborators or partners is forced to grant a license to third parties with respect to any patents relevant to our 
business, our competitive position may be impaired and our business and results of operations may be adversely affected.
Intellectual property rights do not necessarily address all potential threats to our competitive advantage.
The degree of future protection afforded by our intellectual property rights is uncertain because intellectual property rights have 
limitations, and may not adequately protect our business, or permit us to maintain our competitive advantage. The following examples 
are illustrative:
•
others may be able to make compounds that are the same as or similar to our antibody candidates but that are not covered 
by the claims of the patents that we own or have exclusively licensed;

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•
the patents of third parties may have an adverse effect on our business;
•
we or our licensors or any future strategic partners might not have been the first to conceive or reduce to practice the 
inventions covered by the issued patent or pending patent application that we own or have exclusively licensed;
•
we or our licensors or any future strategic partners might not have been the first to file patent applications covering 
certain of our inventions;
•
others may independently develop similar or alternative technologies or duplicate any of our technologies without 
infringing our intellectual property rights;
•
it is possible that our pending patent applications will not lead to issued patents;
•
issued patents that we own or have exclusively licensed may not provide us with any competitive advantage, or may be 
held invalid or unenforceable, as a result of legal challenges by our competitors;
•
our competitors might conduct research and development activities in countries where we do not have patent rights and 
then use the information learned from such activities to develop competitive products for sale in our major commercial 
markets;
•
third parties performing manufacturing or testing for us using our antibody candidates or technologies could use the 
intellectual property of others without obtaining a proper license; and
•
we may not develop additional technologies that are patentable.
Changes in patent laws or patent jurisprudence could diminish the value of patents in general, thereby impairing our ability to 
protect our antibody candidates and technology platforms.
As is the case with other biopharmaceutical companies, our success is heavily dependent on intellectual property, particularly patents. 
Obtaining and enforcing patents in the biopharmaceutical industry involve both technological complexity and legal complexity. 
Therefore, obtaining and enforcing biopharmaceutical patents is costly, time-consuming and inherently uncertain.
In September 2011, the America Invents Act (AIA) was enacted in the United States, resulting in significant changes to the U.S. 
patent system. An important change introduced by the AIA was a transition to a “first-to-file” system for deciding which party should 
be granted a patent when two or more patent applications are filed by different parties claiming the same invention, which went into 
effect on March 16, 2013. Therefore, a third party that now files a patent application in the USPTO before we do could be awarded a 
patent covering an invention of ours even if we created the invention before it was created by the third party. While we are cognizant 
of the time from invention to filing of a patent application, circumstances could prevent us from promptly filing patent applications for 
our inventions.
Among some of the other changes introduced by the AIA were changes that limit where a patentee may file a patent infringement suit 
and providing opportunities for third parties to challenge any issued patent in the USPTO. This applies to all of our U.S. patents, even 
those issued before March 16, 2013. Because of a lower burden of proof in USPTO proceedings compared to the burden of proof in 
U.S. federal courts necessary to invalidate a patent claim, a third party could potentially provide evidence in a USPTO proceeding 
sufficient for the USPTO to hold a claim invalid even though the same evidence would be insufficient to invalidate the claim if first 
presented in a district court action. Accordingly, a third party may attempt to use the USPTO procedures to invalidate our patent 
claims that would not have been invalidated if first challenged by the third party as a defendant in a district court action. The AIA and 
its continued implementation could increase the uncertainties and costs surrounding the prosecution of our patent applications, and the 
patent applications of our existing and future collaborators or licensors and the enforcement or defense of our issued patents.
Depending on decisions by the U.S. Congress, the federal courts, and the USPTO, the laws and regulations governing patents could 
change in unpredictable ways that could weaken our ability to obtain new patents or to enforce our existing patents and patents that we 
might obtain in the future. Similarly, there is complexity and uncertainty related to European patent laws. For example, the European 
Patent Convention was amended in April 2010 to limit the time permitted for filing divisional applications. In addition, the EPO patent 
system is relatively stringent in the type of amendments that are allowed during prosecution. These limitations and requirements could 
adversely affect our ability to obtain new patents in the future that may be important for our business.
Confidentiality agreements with employees, contractors, agents, consultants, collaborators and others may not adequately prevent 
disclosure of trade secrets and protect other proprietary information.

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We consider proprietary trade secrets and/or confidential know-how and unpatented know-how to be important to our business. We 
may rely on trade secrets and/or confidential know-how to protect our technology, especially where patent protection is believed to be 
of limited value. However, trade secrets and/or confidential know-how are difficult to maintain as confidential.
To protect this type of information against disclosure or appropriation by competitors, our policy is to require our employees, 
consultants, contractors, collaborators and advisors to enter into confidentiality agreements with us, our practice is to provide regular 
trainings on the importance of maintaining confidentiality, to promulgate a business code of conduct requiring confidentiality, and 
prohibit the use of non-sanctioned devices with company confidential information. However, current or former employees, 
consultants, contractors, collaborators and advisers may unintentionally or willfully disclose our confidential information to 
competitors, and confidentiality agreements and other precautions taken may not provide an adequate remedy in the event of 
unauthorized disclosure of confidential information or we may be unaware of such disclosure to enforce our confidentiality 
agreements and other remedies. Enforcing a claim that a third party obtained illegally and is using trade secrets and/or confidential 
know-how is expensive, time consuming and unpredictable. The enforceability of confidentiality agreements and theft of trade secret 
claims may vary from jurisdiction to jurisdiction. Furthermore, if a competitor lawfully obtained or independently developed any of 
our trade secrets, we would have no right to prevent such competitor from using that technology or information to compete with us, 
which could harm our competitive position. Additionally, if the steps taken to maintain our trade secrets are deemed inadequate, we 
may have insufficient recourse against third parties for misappropriating the trade secret.
Failure to obtain or maintain trade secrets and/or confidential know-how trade protection could adversely affect our competitive 
position. Moreover, our competitors may independently develop substantially equivalent proprietary information and may even apply 
for patent protection in respect of the same. If successful in obtaining such patent protection, our competitors could limit our use of 
our trade secrets and/or confidential know-how.
Under certain circumstances and to guarantee our freedom to operate, we may also decide to publish some know-how to prevent 
others from obtaining patent rights covering such know-how.
We may be subject to claims by third parties asserting that our employees or we have misappropriated their intellectual property, or 
claiming ownership of what we regard as our own intellectual property.
Many of our employees, including our senior management, were previously employed at universities or at pharmaceutical or 
biotechnology companies, including our competitors or potential competitors. Some of these employees executed proprietary rights, 
non-disclosure and non-competition agreements in connection with such previous employment. Although we take measures including 
by policy, procedure and contract to try to ensure that our employees do not improperly use the proprietary information or know-how 
of others in their work for us, we may be subject to claims that we or these employees have used or disclosed confidential information 
or 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.
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 or sustain damages. 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 commercialize our technology or products. Such a license may not be available on 
commercially reasonable terms or at all. Even if we successfully prosecute or defend against such claims, litigation could result in 
substantial costs and distract management.
Obtaining and maintaining our 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 and annuity fees on any issued patent are due to be paid to the USPTO and foreign patent agencies in several 
stages over the lifetime of the patent. 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. While an 
inadvertent lapse can in many cases be cured by payment of a late fee or by other means in accordance with the applicable rules, there 
are situations in which noncompliance can result in abandonment or lapse of the patent or patent application, resulting in partial or 
complete loss of patent rights in the relevant jurisdiction. Non-compliance events that could result in abandonment or lapse of a patent 
or patent application include failure to respond to official actions within prescribed time limits, non-payment of fees and failure to 
properly legalize and submit formal documents. If we or our existing or future licensors or collaborators fail to maintain the patents 
and patent applications covering our antibody candidates, our competitors might be able to enter the market, which would have an 
adverse effect on our business.
Use of social media could give rise to liability, breaches of data security, or reputational harm.

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We and our employees use social media to communicate internally and externally, as do our contractors, consultants, CROs, and third 
parties, including clinical trial participants. While we have policies and procedures in place governing employee use of social media, 
there is risk that the use of social media by us or our employees or third parties to communicate about our antibody candidates, 
technologies or business may give rise to liability, lead to the loss of trade secrets or other intellectual property, or result in public 
exposure of personal information of our employees, clinical trial patients, customers, and others. Furthermore, negative posts or 
comments about us, our clinical trials, or our antibody candidates, our technologies, and company generally in social media could 
seriously damage our reputation, brand image, and goodwill. Any of these events could have a material adverse effect on our business, 
prospects, operating results, and financial condition and could adversely affect the price of our common shares.
Our information technology systems, or those used by our CROs or other contractors or consultants, may fail or suffer security 
breaches, which could adversely affect our business.
Despite the implementation of security measures, our information technology systems and data and those of our current or future 
CROs or other contractors and consultants are vulnerable to compromise or damage from computer hacking, computer viruses, and 
malware (e.g., ransomware malicious software), fraudulent activity, employee misconduct, human error, telecommunication and 
electrical failures, natural disasters, or other cybersecurity attacks or accidents. Future acquisitions could expose us to additional 
cybersecurity risks and vulnerabilities from any newly acquired information technology infrastructure. Cybersecurity attacks are 
constantly increasing in frequency and sophistication and are made by groups and individuals with a wide range of motives (including 
industrial espionage) and expertise, including by organized criminal groups, “hacktivists,” nation states, and others. As a result of a 
continued hybrid working environment, we may also face increased cybersecurity risks due to our reliance on internet technology and 
the number of our employees who are working remotely, which may create additional opportunities for cybercriminals to exploit 
vulnerabilities. Furthermore, because the techniques used to obtain unauthorized access to, or to sabotage systems change frequently 
and often are not recognized until launched against a target, we may be unable to anticipate these techniques or implement adequate 
preventative measures. Further, as a company with an increasingly global presence, our systems are subject to frequent attacks, which 
are becoming more commonplace in the industry, including attempted hacking, phishing attempts, such as cyber-related threats 
involving spoofed or manipulated electronic communications, which increasingly represent considerable risk. Due to the nature of 
some of the attacks described herein, there is a risk that an attack may remain undetected for a period of time. Even if identified, we 
may be unable to adequately investigate or remediate incidents or breaches due to attackers increasingly using tools and techniques 
that are designed to circumvent controls, to avoid detection, and to remove or obfuscate forensic evidence. While we continue to make 
investments to improve the protection of data and information technology, including in the hiring of IT personnel, periodic cyber 
security awareness trainings, and improvements to IT infrastructure and controls, and conduct regular testing of our systems, there can 
be no assurance that our efforts will prevent service interruptions or security breaches.
We and certain of our service providers are from time to time subject to cyberattack attempts or incidents and security incidents. Any 
cybersecurity incident could adversely affect our business, by leading to, for example, the loss of trade secrets or other intellectual 
property, demands for ransom or other forms of blackmail, or the unauthorized disclosure of personal or other sensitive information of 
our employees, clinical trial patients, customers, and others. Although to our knowledge we have not experienced any significant 
cybersecurity incident to date, if such an event were to occur, it could seriously harm our development programs and our business 
operations. We could be subject to breach notification requirements, regulatory actions taken by governmental authorities, litigation 
under laws that protect the privacy of personal information, or other forms of legal proceedings, which could result in significant 
liabilities or penalties, result in substantial costs and distract management. Further, a cybersecurity incident may disrupt our business 
or damage our reputation, which could have a material adverse effect on our business, prospects, operating results, share price and 
shareholder value, and financial condition. We could also incur substantial remediation costs, including the costs of investigating the 
incident, repairing or replacing damaged systems, restoring normal business operations, implementing increased cybersecurity 
protections, and paying increased insurance premiums.
For example, the loss of clinical trial data from completed, ongoing or future clinical trials could result in delays in our regulatory 
approval efforts and significantly increase our costs to recover or reproduce the data. If a security breach or other incident were to 
result in the unauthorized access to or unauthorized use, disclosure, release or other processing of clinical trial data or personal data, it 
may be necessary to notify individuals, governmental authorities, supervisory bodies, the media, and other parties pursuant to privacy 
and security laws. Likewise, we rely on our third-party research institution collaborators for research and development of our product 
candidates and other third parties for the manufacture of our product candidates and to conduct clinical trials, and similar events 
relating to their information technology systems could also seriously harm our business. Any security compromise affecting us, our 
collaborators or our industry, whether real or perceived, could harm our reputation, erode confidence in the effectiveness of our 
security measures, and lead to regulatory scrutiny. To the extent that any disruption or security breach were to result in a loss of, or 
damage to, our data or systems, or inappropriate disclosure of confidential or proprietary or personal information, we could incur 

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liability, our competitive position could be harmed, and the further development and commercialization of our product candidates 
could be delayed, result in substantial costs and distract management.
Risks Related to Employee Matters and Managing Growth
Our future growth and ability to compete depends on retaining our key personnel and recruiting additional qualified personnel.
Our success depends upon the contributions of our senior leaders, including our board of directors, our senior management, and other 
key scientific and technical personnel, many of whom have been instrumental for us and have substantial experience with our antibody 
candidates and related technologies. The loss of key senior management, managers and senior scientists could delay our research and 
development and clinical trial activities or impair our ability operate the company effectively. In addition, the competition for 
qualified personnel in the biopharmaceutical and pharmaceutical field is increasingly intense, and our future success depends upon our 
ability to attract, retain and motivate highly-skilled scientific, technical and managerial employees. We face competition for personnel 
from other companies, universities, public and private research institutions and other organizations. If our recruitment and retention 
efforts are unsuccessful, it may be difficult for us to implement our business strategy, which could have a material adverse effect on 
our business. Our success also depends on our ability to manage transitions among our senior management and other key personnel. In 
July 2024, Hui Liu, Ph.D., stepped down as Chief Business Officer, Dr. Andrew Joe, M.D., resigned as Chief Medical Officer, Dr. 
Lex Bakker resigned as Chief Development Officer, Dr. Fabian Zohren, M.D., was appointed as Executive Vice President and Chief 
Medical Officer, effective July 1, 2024, and Ms. Audrey Bergan was appointed as Chief People Officer, effective November 4, 2024. 
If we are unable to continue to manage orderly transitions in these cases or for other key personnel in the future, or if we are unable to 
adequately integrate the new Chief Medical Officer, Chief People Officer, or retain our other existing senior management, managers 
and senior scientists, our business may be adversely affected. 
We expect to expand our development, regulatory and sales and marketing capabilities, and as a result, we may encounter 
difficulties in managing our growth, which could disrupt our operations.
We expect to continue to experience significant growth in the number of our employees and the scope of our operations, particularly 
in the areas of drug and clinical development, regulatory affairs, medical affairs, commercialization, sales and marketing. To manage 
our growth, we must continue 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, we may not be able to effectively manage the expansion of our 
operations or recruit and train additional qualified personnel. The 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 Shares
Future sales, or the possibility of future sales, of a substantial number of our common shares could adversely affect the price of 
the shares.
Sales of a substantial number of our common shares in the public market, or the perception in the market that the holders of a large 
number of shares intend to sell shares, could reduce the market price of our common shares. We have registered and intend to continue 
to register all common shares that we may issue under our equity compensation plans. Once registered, these common shares can be 
freely sold in the public market upon issuance, subject to volume limitations applicable to affiliates who hold such shares. In addition, 
in connection with entering into the Lilly Collaboration Agreement, we entered into a Lilly Share Subscription Agreement with Eli 
Lilly, pursuant to which we issued and sold to Eli Lilly 706,834 of our common shares. 
Provisions of our articles of association or Dutch corporate law might deter acquisition bids for us that might be considered 
favorable and prevent or frustrate any attempt to replace or remove the then board members.
Provisions of our articles of association may make it more difficult for a third party to acquire control of us or effect a change in our 
board of directors. These provisions include:
•
the authorization of a class of preferred shares that may be issued to an independent special purpose foundation;
•
the possibility to appoint our board members for staggered terms;
•
provisions stemming from the Dutch large company regime pursuant to which (i) our executive directors will be 
appointed, and can be suspended or dismissed, by the group of non-executive directors, (ii) our non-executive directors 

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will be appointed by our general meeting based on a nomination to be prepared by the group of non-executive directors, 
taking into account recommendation rights for our general meeting and our works council, (iii) our general meeting will 
be able to reject nominees for appointment as non-executive directors by simple majority of votes cast, with these votes 
representing at least one-third of our issued share capital and (iv) our general meeting will only be able to dismiss 
our non-executive directors as a collective, which will require a simple majority of votes cast, with these votes 
representing at least one-third of our issued share capital;
•
a requirement that certain matters, including an amendment of our articles of association, may only be brought to our 
shareholders for a vote upon a proposal by our board of directors.
The board of directors can invoke a statutory cooling-off period of up to 250 days in situations described below. When such cooling-
off period is invoked, our general meeting of shareholders cannot dismiss, suspend or appoint members of the board of directors (or 
amend the provisions in our articles of association dealing with those matters) unless those matters would be proposed by the board of 
directors. This cooling-off period could be invoked by the board of directors in case:
a)
shareholders, using either their shareholder proposal right or their right to request a general meeting of shareholders, 
propose an agenda item for the general meeting of shareholders to dismiss, suspend or appoint a member of the board of 
directors (or to amend any provision in the articles of association dealing with those matters); or
b)
a public offer for the company is made or announced without the company's support, provided, in each case, that the 
board of directors believes that such proposal or offer materially conflicts with the interests of the company and its 
business.
Under the Dutch Corporate Governance Code (DCGC), the board of directors may also invoke a response period of up to 180 days in 
case shareholders, using either their shareholder proposal right or their right to request a general meeting of shareholders, propose an 
agenda item for the general meeting of shareholders which may result in a change in our strategy (including through the dismissal of 
one or more of our board members). If this response period is invoked, the shareholders concerned must give the board of directors the 
opportunity to respond to their intentions before their request is dealt with at a general meeting of shareholders.
Our anti-takeover provision may prevent a beneficial change of control.
We adopted an anti-takeover measure pursuant to which our board of directors may, without shareholder approval, issue (or grant the 
right to acquire) preferred shares. Pursuant to a call option agreement entered into with an independent special purpose foundation, we 
may issue an amount of preferred shares up to 100% of our issued capital held by third parties immediately prior to the issuance of 
such preferred shares.
The preferred shares will be issued to the foundation for their nominal value, of which only 25% will be due upon issuance. The 
voting rights of our shares are based on nominal value and as we expect our shares to continue to trade substantially in excess of 
nominal value, preferred shares issued at nominal value can obtain significant voting power for a substantially reduced price and thus 
be used as a defensive measure. These preferred shares will have both a liquidation and dividend preference over our common shares 
and will accrue cash dividends at a fixed rate. Subject to the foundation exercising its call option under the call option agreement, the 
board may issue these preferred shares to protect us from influences that we believe do not serve our best interests and threaten to 
undermine our continuity, independence and identity. These influences may include a third-party acquiring a significant percentage of 
our common shares, the announcement of a public offer for our common shares, other concentration of control over our common 
shares or any other form of pressure on us to alter our strategic policies. The foundation’s articles of association provide that it will act 
to serve the best interests of us, our associated business and all parties connected to us, by opposing any influences that conflict with 
these interests and threaten to undermine our continuity, independence and identity. This foundation is structured to operate 
independently of us.
Holders of our common shares outside the Netherlands may not be able to exercise preemptive rights.
In the event of an increase in our share capital, holders of our common shares are generally entitled under Dutch law to full 
preemptive rights, unless these rights are excluded either by a resolution of the general meeting of shareholders, or by a resolution of 
the board (if the board has been designated by the general meeting of shareholders for this purpose). Certain holders of our common 
shares outside the Netherlands, in particular U.S. holders of our common shares, may not be able to exercise preemptive rights unless 
a registration statement under the Securities Act is declared effective with respect to our common shares issuable upon exercise of 
such rights or an exemption from the registration requirements is available.

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The rights of our shareholders may be different from the rights of shareholders in companies governed by the laws of U.S. 
jurisdictions.
We are a Dutch public company with limited liability (naamloze vennootschap). Our corporate affairs are governed by our articles of 
association and by the laws governing companies incorporated in the Netherlands. The rights of shareholders and the responsibilities 
of members of our board may be different from the rights and obligations of shareholders and directors in companies governed by the 
laws of U.S. jurisdictions. In the performance of their duties, the members of our board are required by Dutch law to consider the 
interests of our company, its shareholders, its employees and other stakeholders, in all cases with due observation of the principles of 
reasonableness and fairness. It is possible that some of these parties will have interests that are different from, or in addition to, the 
interests of our shareholders.
We are not obligated to and do not comply with all the best practice provisions of the Dutch Corporate Governance Code. This may 
affect the rights of our shareholders.
We are subject to the DCGC. The DCGC contains both principles and best practice provisions for board of directors, shareholders and 
general meetings of shareholders, financial reporting, auditors, disclosure, compliance and enforcement standards. The DCGC applies 
to all Dutch companies listed on a government-recognized stock exchange, whether in the Netherlands or elsewhere, including 
Nasdaq. The principles and best practice provisions apply to our board (in relation to role and composition, conflicts of interest and 
independence requirements, board committees and remuneration), shareholders and the general meeting of shareholders (for example, 
regarding anti-takeover protection and our obligations to provide information to our shareholders) and financial reporting (such as 
external auditor and internal audit requirements). We do not comply with all the best practice provisions of the DCGC. As a result, the 
rights of our shareholders may be affected and our shareholders may not have the same level of protection as a shareholder in another 
Dutch public company with limited liability (naamloze vennootschap) listed in the Netherlands that fully complies with the DCGC.
Claims of U.S. civil liabilities may not be enforceable against us.
We are incorporated under the laws of the Netherlands. Most of our assets are located outside the United States. Currently, (i) there is 
no treaty in force between the United States and the Netherlands for the reciprocal recognition and enforcement of judgments, other 
than arbitration awards, in civil and commercial matters and (ii) both the Hague Convention on Choice of Court Agreements (2005) 
and the Hague Judgments Convention (2019) have entered into force for the Netherlands, but have not entered into force for the 
United States. Consequently, a judgment rendered by a court in the United States will not automatically be recognized and enforced by 
the competent Dutch courts. However, if a person has obtained a judgment rendered by a court in the United States that is enforceable 
under the laws of the United States and files a claim with the competent Dutch court, the Dutch court will in principle give binding 
effect to that United States judgment if (i) the jurisdiction of the United States court was based on a ground of jurisdiction that is 
generally acceptable according to international standards, (ii) the judgment by the United States court was rendered in legal 
proceedings that comply with the Dutch standards of proper administration of justice including sufficient safeguards (behoorlijke 
rechtspleging), (iii) binding effect of such United States judgment is not contrary to Dutch public order (openbare orde) and (iv) the 
judgment by the United States court is not incompatible with a decision rendered between the same parties by a Dutch court, or with a 
previous decision rendered between the same parties by a foreign court in a dispute that concerns the same subject and is based on the 
same cause, provided that the previous decision qualifies for recognition in the Netherlands. Even if such a United States judgment is 
given binding effect, a claim based thereon may, however, still be rejected if the United States judgment is not or no longer formally 
enforceable. Moreover, if the United States judgment is not final (for instance when appeal is possible or pending) a competent Dutch 
court may postpone recognition until the United States judgment will have become final, refuse recognition under the understanding 
that recognition can be asked again once the United States judgment will have become final, or impose as a condition for recognition 
that security is posted. A competent Dutch court may deny the recognition and enforcement of punitive damages or other awards. 
Moreover, a competent Dutch court may reduce the amount of damages granted by a United States court and recognize damages only 
to the extent that they are necessary to compensate actual losses or damages. Thus, certain investors may not be able, or experience 
difficulty, to enforce a judgment obtained in a United States court against us or our officers (functionarissen).
Our articles of association include a U.S. federal forum selection clause designating federal courts as the sole and exclusive forum 
for certain types of actions and proceedings that may be initiated by our shareholders, which could limit our shareholders’ ability 
to obtain a favorable judicial forum for disputes with us or our directors, officers, or employees.
Our articles of association provide that, unless we consent in writing to an alternative forum, the sole and exclusive forum for any 
complaint asserting a cause of action arising under the Securities Act, to the fullest extent permitted by applicable law, shall be the 
federal district courts of the United States of America (the “Federal Forum Provision”). The Federal Forum Provision in our articles of 
association may impose additional litigation costs on shareholders in pursuing any such claims. Additionally, the forum selection 
clause may limit our shareholders’ ability to bring a claim in a forum that they find favorable for disputes with us or our directors, 

93
officers or employees, which may discourage such lawsuits against us and our directors, officers and employees even though an 
action, if successful, might benefit our shareholders. In addition, while the Delaware Supreme Court ruled in March 2020 that federal 
forum selection provisions purporting to require claims under the Securities Act be brought in federal court were “facially valid” 
under Delaware law, there is uncertainty as to whether other courts will enforce our Federal Forum Provision. If the Federal Forum 
Provision is found to be unenforceable, we may incur additional costs associated with resolving such matters. The Federal Forum 
Provision may also impose additional litigation costs on shareholders who assert that the provision is not enforceable or invalid. The 
Court of Chancery of the State of Delaware and the United States District Court for the District of Massachusetts may also reach 
different judgments or results than would other courts, including courts where a shareholder considering an action may be located or 
would otherwise choose to bring the action, and such judgments may be more or less favorable to us than our shareholders.
We may be classified as a passive foreign investment company (PFIC) for U.S. federal income tax purposes, which could result in 
adverse U.S. federal income tax consequences to U.S. investors in our common shares.
Based on the value of our assets, including goodwill, and composition of our income, assets and operations for the taxable year 2024, 
we do not believe we were a PFIC for U.S. federal income tax purposes for that taxable year. A non-U.S. company generally will be 
considered a PFIC for any taxable year if (i) at least 75% of its gross income for such taxable year is passive income (including 
interest income), or (ii) at least 50% of the value of its assets (based on an average of the quarterly values of the assets during such 
taxable year) is attributable to assets that produce or are held for the production of passive income. The value of our assets generally is 
determined by reference to the market price of our common shares, which may fluctuate considerably. In addition, the composition of 
our income and assets is affected by how, and how quickly, we spend the cash we raise. It is possible the Internal Revenue Service 
could determine that we were a PFIC for the taxable year 2024. If we were to be treated as a PFIC for any taxable year during which a 
U.S. Holder (as defined below) holds our common shares, certain adverse U.S. federal income tax consequences could apply to such 
U.S. Holder. Once treated as a PFIC for any taxable year in which a U.S. Holder owns equity in such foreign corporation, a foreign 
corporation will generally continue to be treated as a PFIC for all subsequent taxable years with respect to such U.S. Holder. 
If we were to be a PFIC, “excess distributions” (as such term is defined in the United States Internal Revenue Code of 1986, as 
amended (the U.S. Tax Code)) to a U.S. Holder, and any gain recognized by a U.S. Holder on a disposition of our common shares 
would be taxed in potentially unfavorable ways. Among other consequences, our dividends would be taxed at the regular rates 
applicable to ordinary income, rather than the reduced rate applicable to certain dividends received by an individual from a qualified 
foreign corporation, and, to the extent that they constituted excess distributions, certain interest charges may apply, and gains on the 
sale of our shares would be treated in the same way as excess distributions. In addition, the U.S. Holder would be subject to detailed 
reporting obligations. The tests for determining PFIC status are applied annually and it is difficult to make accurate predictions of 
future income and assets, which are relevant to the determination of any future PFIC status. As such, we cannot provide any 
assurances regarding our PFIC status for any past, current or future taxable years. Further, we cannot provide any assurances that we 
will furnish to any U.S. Holder information that may be necessary to comply with the aforementioned reporting and tax payment 
obligations. U.S. Holders should consult their tax advisors regarding the potential application of these rules to their investment in our 
common shares, including the potential availability and advisability of an election to treat us as a qualified electing fund or a mark-to-
market election. 
A “U.S. Holder” is a holder who, for U.S. federal income tax purposes, is a beneficial owner of our common shares and is:
(1)
a citizen or individual resident of the United States;
(2)
a corporation, or other entity taxable as a corporation, created or organized in or under the laws of the United States, any 
state therein or the District of Columbia; 
(3)
an estate, the income of which is subject to U.S. federal income taxation regardless of its source; or
(4)
a trust that (a) is subject to the primary supervision of a U.S. court and the control of one or more “United States 
persons” (within the meaning of Section 7701(a)(30) of the U.S. Tax Code) or (b) has a valid election in effect to be 
treated as a United States person for U.S. federal income tax purposes. 
If a U.S. Holder is treated as owning at least 10% of our common shares, such holder may be subject to adverse U.S. federal 
income tax consequences.
If a U.S. Holder is treated as owning (directly, indirectly or constructively) at least 10% of the value or voting power of our common 
shares, such U.S. Holder may be treated as a “United States shareholder” with respect to each “controlled foreign corporation” in our 
group (if any) as such term is defined in the U.S. Tax Code. A United States shareholder of a controlled foreign corporation may be 
required to report annually and include in its U.S. taxable income, as ordinary income, its pro rata share of “Subpart F income,” 

94
“global intangible low-taxed income” and investments in U.S. property by the controlled foreign corporation, regardless of whether 
the controlled foreign corporation makes any distributions. An individual that is a United States shareholder with respect to a 
controlled foreign corporation generally would not be allowed certain tax deductions or foreign tax credits that would be allowed to a 
United States shareholder that is a corporation. Failure to comply with these reporting obligations may subject a United States 
shareholder to significant monetary penalties and may extend the statute of limitations with respect to such United States shareholder’s 
U.S. federal income tax return for the year for which reporting was due. We cannot provide any assurances that we will assist 
investors in determining whether we or any of our future non-U.S. subsidiaries is treated as a controlled foreign corporation or 
whether such investor is treated as a United States shareholder with respect to any such controlled foreign corporations. Further, we 
cannot provide any assurances that we will furnish to any United States shareholders information that may be necessary to comply 
with the aforementioned reporting and tax payment obligations. U.S. Holders should consult their tax advisors regarding the potential 
application of these rules to their investment in our common shares. The risk of being subject to increased taxation may deter our 
current shareholders from increasing their investment in us and others from investing in us, which could impact the demand for, and 
value of, our common shares.
General Risk Factors
The price of our common shares may be volatile and may fluctuate due to factors beyond our control.
The share price of publicly traded emerging biopharmaceutical and drug discovery and development companies has been highly 
volatile and is likely to remain highly volatile in the future. The market price of our common shares may fluctuate significantly due to 
a variety of factors, including:
•
positive or negative results of testing and clinical trials by us, strategic partners or competitors;
•
delays in entering into strategic relationships with respect to development and/or commercialization of our antibody 
candidates or entry into strategic relationships on terms that are not deemed to be favorable to us;
•
technological innovations or commercial product introductions by us or competitors;
•
changes in government regulations;
•
developments concerning proprietary rights, including patents and litigation matters;
•
public concern relating to the commercial value or safety of any of our antibody candidates;
•
financing or other corporate transactions;
•
publication of research reports or comments by securities or industry analysts;
•
general market conditions in the pharmaceutical industry or in the economy as a whole;
•
political instability in the United States and Europe, including the failure of the United States Federal government to 
raise the debt ceiling; 
•
global geopolitical instability, including the ongoing conflicts in Europe and the Middle east; or
•
other events and factors, many of which are beyond our control.
These and other market and industry factors may cause the market price and demand for our common shares to fluctuate substantially, 
regardless of our actual operating performance, which may limit or prevent investors from readily selling their common shares and 
may otherwise negatively affect the liquidity of our common shares. In addition, the stock market in general, and biopharmaceutical 
companies in particular, have experienced extreme price and volume fluctuations that have often been unrelated or disproportionate to 
the operating performance of these companies.
Unstable market and economic conditions may have serious adverse consequences on our business, financial condition and share
 price.

95
The global economy, including credit and financial markets, has recently experienced extreme volatility and disruptions, including 
severely diminished liquidity and credit availability, rising interest and inflation rates, declines in consumer confidence, declines in 
economic growth, increases in unemployment rates and uncertainty about economic stability. If the equity and credit markets continue 
to deteriorate or the Netherlands or the United States enters a recession, it may make any necessary debt or equity financing more 
difficult to obtain in a timely manner or on favorable terms, more costly or more dilutive. In addition, there is a risk that one or more 
of our CROs, suppliers or other third-party providers may not survive an economic downturn or recession. As a result, our business, 
results of operations and price of our common shares may be adversely affected.
Business interruptions could adversely affect our operations. 
Our operations are vulnerable to interruption by fire, severe weather conditions, power loss, telecommunications failure, terrorist 
activity, public health crises and pandemic diseases, such as COVID-19, and other natural and man-made disasters or events beyond our 
control. Our facilities are located in regions that experience severe weather from time to time. We have not undertaken a systematic 
analysis of the potential consequences to our business and financial results from a major tornado, flood, fire, earthquake, power loss, 
terrorist activity, public health crisis, pandemic diseases or other disasters and do not have a recovery plan for such disasters. In addition, 
we do not carry sufficient insurance to compensate us for actual losses from interruption of our business that may occur, and any losses 
or damages incurred by us could harm our business. The occurrence of any of these business disruptions could seriously harm our 
operations and financial condition and increase our costs and expenses.
Because we do not expect to pay cash dividends for the foreseeable future, any returns on an investment in our common shares 
will likely depend entirely upon any future appreciation in the price of our common shares, which is uncertain.
We have not paid any cash dividends since our incorporation. Even if future operations lead to significant levels of distributable 
profits, we currently intend that any earnings will be reinvested in our business and that cash dividends will not be paid until we have 
an established revenue stream to support continuing cash dividends. Payment of any future dividends to shareholders will in addition 
effectively be at the discretion of the general meeting, upon proposal of the board of directors, after taking into account various factors 
including our business prospects, cash requirements, financial performance and new product development. In addition, payment of 
future cash dividends may be made only if our shareholders’ equity exceeds the sum of our paid-in and called-up share capital plus the 
reserves required to be maintained by Dutch law or by our articles of association. Accordingly, investors cannot rely on cash dividend 
income from our common shares and any returns on an investment in our common shares will likely depend entirely upon any future 
appreciation in the price of our common shares. In addition, the low trading volume of our common shares may adversely affect the 
trading price of our common shares, and our shareholders may not be able to sell their common shares for a price higher than the price 
they paid for our common shares.
If securities or industry analysts publish inaccurate or unfavorable research about our business, the price of our common shares 
and our trading volume could decline.
The trading market for our common shares depends in part on the research and reports that securities or industry analysts publish 
about us or our business. If one or more of the analysts who cover us downgrade our common shares or publish inaccurate or 
unfavorable research about our business, the price of our common shares would likely decline. If one or more of these analysts cease 
coverage of us or fail to publish reports on us regularly, demand for our common shares could decrease, which might cause the price 
of our common shares and trading volume to decline.

96
We will continue to incur increased costs as a result of operating as a public company with limited liability (naamloze 
vennootschap), and our management team is required to devote substantial time to new compliance initiatives and corporate 
governance practices.
As a public company, and particularly now that we no longer qualify as an emerging growth company or a smaller reporting company, 
we will continue to incur significant legal, accounting and other expenses related to our operation as a public company. The Sarbanes-
Oxley Act of 2002 (SOX), the Dodd-Frank Wall Street Reform and Consumer Protection Act, the listing requirements of the Nasdaq 
Global Market, or Nasdaq, and other applicable securities rules and regulations impose various requirements on reporting public 
companies, including the establishment and maintenance of effective disclosure and financial controls and corporate governance 
practices. Our board of directors and other personnel continues to devote a substantial amount of time to these compliance initiatives. 
Moreover, these rules and regulations have and will continue to increase our legal and financial compliance costs and make some 
activities more time-consuming and costly.
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. This could result 
in continuing uncertainty regarding compliance matters and higher costs necessitated by ongoing revisions to disclosure and 
governance practices.
Pursuant to Section 404(a) of SOX (Section 404) we are required to furnish a report by our management on our internal control over 
financial reporting with our Annual Report on Form 10-K. Additionally, we are required to include an attestation report on internal 
control over financial reporting issued by our independent registered public accounting firm. To maintain compliance with Section 
404(a), we engage in a process to document and evaluate our internal control over financial reporting, which is both costly and 
challenging. In this regard, we continue to dedicate internal resources and have engaged outside consultants and adopted a detailed 
work plan to assess and document the adequacy of our 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. Despite our efforts, there is a risk that we will not be able to 
maintain effective internal control over financial reporting as required by Section 404. Material weaknesses or significant deficiencies 
in our internal control over financial reporting could also reduce our ability to obtain financing or could increase the cost of any 
financing we obtain. If we 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. 
The varied and differing positions on environmental sustainability and social initiatives by governments and other stakeholders 
could increase our costs, harm our reputation and adversely impact our financial results.
There has been varied and differing focus by investors, patients, environmental activists, the media and governmental and 
nongovernmental organizations among other stakeholders on a variety of environmental, social and other sustainability matters. We 
may experience pressure to make commitments relating to sustainability matters that affect us, including the design and 
implementation of specific risk mitigation strategic initiatives relating to sustainability. Expectations regarding the management of 
sustainability initiatives continues to evolve rapidly. While we may from time to time engage in various initiatives (including but not 
limited to voluntary disclosures, policies, or goals) to improve our sustainability profile or respond to stakeholder expectations, in 
compliance with applicable laws, regulations and other legal requirements, we cannot guarantee that these initiatives will have the 
desired effect. If we are not effective in addressing environmental, social and other sustainability matters affecting our business, or 
setting and meeting relevant sustainability goals, our reputation and financial results may suffer. In addition, even if we are effective at 
addressing such concerns, we may experience increased costs as a result of executing upon our sustainability goals that may not be 
offset by any benefit to our reputation, which could have an adverse impact on our business and financial condition.
In addition, this emphasis on environmental, social and other sustainability matters has resulted and may result in the adoption of new 
laws and regulations, including new reporting requirements. We are currently assessing the potential impacts of the adopted or 
proposed laws, as well as other sustainability related disclosure obligations and evolving legal and regulatory requirements, to which 
we may be subject. If we fail to comply with new laws, regulations or reporting requirements, our reputation and business could be 
adversely impacted.

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Item 1B. Unresolved Staff Comments. 
None.
Item 1C. Cybersecurity
Cybersecurity Risk Management and Strategy
We have established policies and processes for identifying, assessing, and managing material risk from cybersecurity threats, and have 
integrated these processes into our overall risk management systems and processes. We routinely assess material risks from 
cybersecurity threats, including any potential unauthorized occurrence on or conducted through our information systems that may 
result in adverse effects on the confidentiality, integrity, or availability of our information systems or any information residing therein. 
We design and are assessing our cybersecurity risk management program based on the ISO27001:2022 standard, for which we 
received certification in 2024. We use the ISO27001:2022 framework as a structure to help us identify, assess, and manage 
cybersecurity risks relevant to our business. 
We conduct periodic risk assessments to identify cybersecurity threats, as well as assessments in the event of a material change in our 
business practices that may affect information technology systems that are vulnerable to cybersecurity threats. These risk assessments 
include identification of reasonably foreseeable internal and external risks, the likelihood and potential damage that could result from 
such risks, and the sufficiency of existing policies, procedures, systems, and safeguards in place to manage such risks. 
Following these risk assessments, we re-design, implement, and maintain reasonable safeguards to minimize identified risks; 
reasonably address any identified gaps in existing safeguards; and regularly monitor the effectiveness of our safeguards. Primary 
responsibility for assessing, monitoring and managing our cybersecurity risks rests with our IT department who reports to our Chief 
Operating Officer, to manage the risk assessment and mitigation process. The cybersecurity risk management program also includes 
tools and activities to prevent, detect, and analyze current and emerging cybersecurity threats, and plans and strategies to address 
threats and incidents.
As part of our overall risk management system, we monitor and test our safeguards and train our employees on these safeguards, in 
collaboration with IT and management. Personnel at all levels and departments are made aware of our cybersecurity policies through 
regular communication, trainings and mock cybersecurity exercises to increase company awareness. 
We engage consultants, auditors or other third parties in connection with our risk assessment processes. These parties assist us with 
designing and implementing our cybersecurity policies and procedures, as well as to monitor and test our safeguards, and 
investigations on an as needed basis. We contractually require third-party service providers to implement and maintain appropriate 
security measures, consistent with applicable laws, to implement and maintain reasonable security measures in connection with their 
work with us. 
We have not encountered cybersecurity challenges that have materially impaired our operations or financial standing. For additional 
information regarding risks from cybersecurity threats, please see section “Risk Factors --Our information technology systems, or 
those used by our CROs or other contractors or consultants, may fail or suffer security breaches, which could adversely affect our 
business,” in this Annual Report on Form 10-K.
Cybersecurity governance
One of the key functions of our board of directors is informed oversight of our risk management process, including risks from 
cybersecurity threats. Our board of directors is responsible for monitoring and assessing strategic risk exposure, and our executive 
officers are responsible for the day-to-day management of the material risks we face. Our board of directors administers its 
cybersecurity risk oversight function directly as a whole, as well as through the audit committee. 
Our Chief Operating Officer and management team are primarily responsible for assessing and managing our material risks from 
cybersecurity threats with assistance from the Head of IT Security and Compliance, the supporting internal team and support of third-
party service providers. 
Our Chief Operating Officer oversees our cybersecurity policies and processes, including those described in “Cybersecurity Risk 
Management and Strategy” above. 
Our Chief Operating Officer and Head of IT Security provide periodic briefings to the audit committee regarding our company’s 
cybersecurity risks and activities, including any recent cybersecurity incidents and related responses, cybersecurity systems testing, 
activities of third parties, and policy and procedures, and changes in applicable law or regulations concerning such subject matter. Our 

98
audit committee is charged with, and is able to pass resolutions relating to the application of information and communication 
technology by the Company, including risks relating to cybersecurity. Moreover, periodic briefings are also provided to the board of 
directors relating to our cybersecurity risks and activities, including any recent cybersecurity incidents and related responses, 
cybersecurity systems testing, activities of third parties, and policy and procedures, and changes in applicable law or regulations 
concerning such subject matter. 
Our team that is responsible for assessing and our material risks from cybersecurity threats, including our Chief Operating Officer, 
Chief Financial Officer, and Executive Director, Head of IT Security and Compliance, which collectively have more than a combined 
30 years of risk management experience. Our team’s experience includes the Executive Director, Head of IT Security and 
Compliance, who has an extensive (25+ years) track record on cyber- and IT risks management, developing security and compliance 
programs and frameworks and leading IT security organizations, our Chief Financial Officer who, serving that role at Merus and prior 
companies and serving previously as Audit Committee chairperson for Merus and current Audit Committee chairperson at Kala 
Pharmaceuticals, has devoted significant attention to evaluation of risks posed by cybersecurity threats, and means to mitigate those 
risks, while evaluating strategies to gain a high level of cyber security, and our Chief Operating Officer, who has managed the IT 
organization at Merus for approximately five years and has devoted significant attention to evaluation of risks posed by cybersecurity 
threats, and means to mitigate those risks, and review of U.S. jurisprudence concerning protection of confidential information and 
trade secrets and has participated in trainings on cybersecurity threat defense and response, and cybersecurity strategies from a legal 
perspective. 
Item 2. Properties. 
During 2022, we leased office and laboratory space in Utrecht, the Netherlands. This facility served as our previous corporate 
headquarters and central laboratory facility through December 2022. The leases for this space terminated on January 1, 2023. In 
December 2022, we moved into approximately 4,957 square meters of office and laboratory space in a new multi-tenant office 
building in Utrecht, the Netherlands, which serves as our new corporate headquarters and central laboratory facility. The new lease 
commenced on April 5, 2022 and has a term of ten years. We also entered into a lease for 7,583 square feet of additional office space 
in Cambridge, Massachusetts, which commenced on April 1, 2019 and has a term of seven years. 
Item 3. Legal Proceedings. 
From time to time, we may be involved in various other claims and legal proceedings relating to claims arising out of our operations. 
We are not currently a party to any legal proceedings, which could be deemed to be material.
Particular legal proceedings are described in Note 10 of our Consolidated Financial Statements included in this Annual Report on 
Form 10-K.
Item 4. Mine Safety Disclosures.
Not applicable.

99
PART II
Item 5. Market for Registrant’s Common Equity, Related Shareholder Matters and Issuer Purchases of Equity Securities. 
Market Information and Holders
Our common shares are traded on The Nasdaq Global Market under the symbol “MRUS.” Trading of our common shares commenced 
on May 24, 2016, following the completion of our initial public offering. 
As of February 21, 2025, the number of holders of record of our common shares was 266. 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 shares. We intend to retain all of our future earnings, if any, to finance 
the growth and development of our business. We do not intend to pay cash dividends to our shareholders in the foreseeable future.
Purchases of Equity Securities by the Issuer or Affiliated Purchasers
We did not repurchase any of our equity securities during the quarter ended December 31, 2024.
Recent Sales of Unregistered Securities
None. 
Performance Graph 
 
The following graph and table illustrate the total return from December 31, 2019 through December 31, 2024, for (i) our common 
shares, (ii) the Loncar Cancer Immunotherapy ETF, and (iii) NASDAQ Biotechnology (TR). The graph and the table assume that 
$100 was invested on December 31, 2019 in each of our common shares, the Loncar Cancer Immunotherapy ETF, and NASDAQ 
Biotechnology (TR), and that any dividends were reinvested. The comparisons reflected in the graph and table are not intended to 
forecast the future performance of our common shares and may not be indicative of our future performance.
 
Item 6. [Reserved]

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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 (U.S. 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 important 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. 
A discussion regarding our financial condition and results of operations for the year ended December 31, 2024 compared to the year 
ended December 31, 2023 is presented below. A discussion regarding our financial condition and results of operations for the year 
ended December 31, 2023 compared to the year ended December 31, 2022 is included under “Management’s Discussion and Analysis 
of Financial Condition and Results of Operations” in our Annual Report on Form 10-K for the year ended December 31, 2023.
Overview
General
We are an oncology company developing innovative antibody therapeutics. Our pipeline of full-length human multispecific antibody 
candidates is generated from our proprietary technology platforms, which are able to generate a diverse array of antibody binding 
domains, or Fabs, against virtually any target. Our antibody binding domain generally consists of a target-specific heavy chain paired 
with a common light chain. Multiple binding domains can be combined to produce novel multispecific antibodies that bind to a wide 
range of targets and display novel and innovative biology. These platforms, referred to as Biclonics® and Triclonics®, allow us to 
generate large numbers of diverse panels of bispecific and trispecific antibodies (Multiclonics®), respectively, which can then be 
functionally screened in large-scale cell-based assays to identify those unique molecules that possess novel biology, which we believe 
are best suited for a given therapeutic application. Further, by binding to multiple targets, Biclonics® and Triclonics® may be 
designed to provide a variety of mechanisms of action, including simultaneously blocking receptors that drive tumor cell growth and 
survival and mobilizing the patient’s immune response by engaging T cells, and/or activating various killer cells to eradicate tumors. 
Our Multiclonics® are compatible with a range of linkers and payloads to generate antibody-drug conjugates (ADClonics®) capable of 
binding two or three different targets with the potential for improved binding selectivity, internalization and cancer cell killing 
activity. 
Our technology platforms employ an assortment of patented technologies and techniques to generate human antibodies. We utilize our 
patented MeMo® mouse to produce a host of antibodies with diverse heavy chains and a common light chain that are capable of 
binding to virtually any antigen target. We use our patented heavy chain and CH3 domain dimerization technology to generate 
substantially pure bispecific and trispecific antibodies. We employ our patented Spleen to Screen® technology to efficiently screen 
panels of diverse heavy chains, designed to allow us to rapidly identify Biclonics® and Triclonics® therapeutic candidates with 
differentiated modes of action for pre-clinical and clinical testing. We use our patented Triclonics® format to generate multispecific 
antibodies capable of binding to three different epitopes or antigens.
The FDA approved BIZENGRI® (zenocutuzumab-zbco), the first and only treatment indicated for adults with pancreatic 
adenocarcinoma or NSCLC that are advanced, unresectable or metastatic and harbor a neuregulin 1 (NRG1) gene fusion who have 
disease progression on or after prior systemic therapy. Using our Biclonics® platform we have produced, and are currently 
developing, the following candidates: MCLA-128 (zenocutuzumab), which we are exploring for potential other development 
opportunities beyond NRG1 fusion; MCLA-158 (petosemtamab) for the potential treatment of solid tumors, including 1L PD-L1+ r/m 
HNSCC in combination with pembrolizumab, and 2/3L r/m HNSCC as monotherapy; and in mCRC in 1L and 2L in combination with 
standard chemotherapy and 3L+ mCRC as monotherapy; MCLA-129, for the potential treatment of lung and other solid tumors, which 
is subject to a collaboration and license agreement, which permits Betta Pharmaceuticals Co. Ltd. (Betta) to exclusively 
commercialize MCLA-129 in China, if approved, while Merus retains full ex-China rights. Furthermore, we have a pipeline of 
proprietary antibody candidates in pre-clinical development and intend to further leverage our ADClonics®, Biclonics® and 
Triclonics® technology platforms to identify multispecific antibody candidates and multispecific ADCs and advance them into 
clinical development.
Funding Our Operations
We are an oncology company and have not yet generated any revenue from product sales. We expect to incur significant expenses and 
operating losses for the foreseeable future as we advance our antibody candidates from discovery through pre-clinical development 
and into clinical trials and seek regulatory approval and pursue commercialization of any approved antibody candidate. We have 

101
exclusively licensed to PTx the right to commercialize BIZENGRI® (zenocutuzumab-zbco), in the United States, as the first and only 
treatment indicated for adults with pancreatic adenocarcinoma or NSCLC that are advanced unresectable or metastatic and harbor a 
neuregulin 1 (NRG1) gene fusion who have disease progression on or after prior systemic therapy. Beyond zenocutuzumab, if we 
obtain regulatory approval for any of our other antibody candidates, if appropriate, we expect to incur significant commercialization 
expenses related to product manufacturing, marketing, sales and distribution, and compliance. 
We anticipate that we will require additional financing to support our continuing operations. Until such time as we can generate 
significant revenue from product sales, if ever, we expect to finance our operations through a combination of public or private equity 
or debt financings or other sources, which may include collaborations, business development and licensing opportunities with third 
parties. Adequate additional financing may not be available to us on acceptable terms, or at all. For example, the trading prices for our 
and other biopharmaceutical companies’ stock have been highly volatile as a result of the United States political environment, 
disruptions and extreme volatility in the global economy, including rising inflation and interest rates, declines in economic growth, 
global instability including the ongoing geopolitical conflicts in Europe and the Middle East. As a result, we may face difficulties 
raising capital through sales of our common shares and any such sales may be on unfavorable terms. See “The price of our common 
shares may be volatile and may fluctuate due to factors beyond our control.” in Part I, Item 1A of this Annual Report on Form 10-K. 
Our inability to raise capital as and when needed would have a negative impact on our financial condition and our ability to pursue our 
business strategy. We will need to generate significant revenue to achieve profitability, and we may never do so.
Based on our current operating plan, we expect that our existing cash, cash equivalents and marketable securities of $724.0 million as 
of December 31, 2024 will fund our operations into 2028. We have based this estimate on assumptions that may prove to be wrong, 
particularly as the process of testing product 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.
Clinical Programs
Petosemtamab (MCLA-158: EGFR x LGR5 Biclonics®): Solid Tumors
Phase 3 registrational trial investigating petosemtamab in combination with pembrolizumab in 1L PD-L1+ r/m head and neck 
squamous cell carcinoma (HNSCC), the LiGeR-HN1 trial, and phase 3 registrational trial investigating petosemtamab monotherapy 
in 2/3L HNSCC, the LiGeR-HN2 trial, are enrolling; phase 2 trial in 1L and 2L metastatic colorectal cancer (mCRC) cohort of 
petosemtamab in combination with standard chemotherapy, and in 3L+ mCRC as monotherapy are enrolling; a clinical update on the 
phase 2 investigation of petosemtamab in 1L r/m PD-L1+ HNSCC is planned for the first half 2025, and a clinical update on 
petosemtamab in mCRC is planned for the second half of 2025.
We have confirmed through feedback with the U.S. Food and Drug Administration (the "FDA") that petosemtamab 1500 mg every 
two weeks is appropriate for further development in HNSCC as monotherapy, and in combination with pembrolizumab. 
In June 2024 we provided an interim clinical data  from the ongoing  phase 1/2 trial of petosemtamab with pembrolizumab in 1L 
PDL1+ r/m HNSCC at the 2024 ASCO® Annual Meeting. As of a March 6, 2024 data cutoff, 45 patients (pts) were treated. The 
efficacy population consisted of 4 pts who had been treated by November 6, 2023, who had the opportunity for 4 or more months 
follow up, with ≥2 treatment cycles and ≥1 post-baseline tumor assessment; or who discontinued early due to disease progression or 
death. Two pts were not included: One pt withdrew consent prior to first tumor assessment and the other pt discontinued due to 
toxicity with less than 2 cycles of treatment. The response rate overall (N=24) was 67%, including 1 confirmed complete response 
(CR), 12 confirmed partial responses (PRs) and 3 unconfirmed PRs (all of whom confirmed after the data cutoff) by Response 
Evaluation Criteria in Solid Tumors (RECIST) v1.1. per investigator assessment. Responses were observed regardless of HPV status, 
3 of 4 pts with HPV associated cancer responded, and across PD-L1+ levels treated (CPS 1-19: 60% [6/10]; CPS ≥ 20: 71% [10/14]). 
At the time of data cutoff, 32 pts of the 45 enrolled, remained on treatment, including 14 of 16 responders and 18 of the initial 26 pts 
enrolled. For the 45 pts treated median follow up was 3.6 months.The combination was well tolerated and no significant overlapping 
toxicities with pembrolizumab were observed and treatment-emergent adverse events (AEs) were reported in 45 pts. Most were Grade 
(G) 1 or 2 in severity (no G4–5 were observed). Infusion-related reactions (IRRs) (composite term) were reported in 38% (all Gs) and 
7% (G3) of pts, most occurred during the first infusion and resolved. We plan to provide updated efficacy, durability and safety data 
from this cohort in the first half of 2025.
In July 2024, we announced the first patient was dosed in LiGeR-HN2, a phase 3 trial evaluating the efficacy and safety of 
petosemtamab in r/m 2/3L HNSCC compared to standard of care. In this trial, patients will be randomized to petosemtamab 
monotherapy or investigator’s choice of single agent chemotherapy or cetuximab.
In September 2024, we announced the first patient was dosed in LiGeR-HN1, a phase 3 trial evaluating the efficacy and safety of 
petosemtamab in combination with pembrolizumab in 1L r/m HNSCC expressing PD-L1 (CPS≥1). In this trial, patients will be 
randomized to petosemtamab and pembrolizumab or pembrolizumab monotherapy.

102
We believe a randomized registration trial in HNSCC with an overall response rate endpoint could potentially support accelerated 
approval and the overall survival results from the same study could potentially verify its clinical benefit to support regular approval.
In December 2024, we shared clinical data on petosemtamab monotherapy in patients with previously treated r/m HNSCC at the 
European Society for Medical Oncology (ESMO®) Asia Congress. In this presentation, we presented updated clinical data from the 
ongoing phase 1/2 trial of petosemtamab in previously treated HNSCC, previously presented at the American Association of Cancer 
Research (AACR) Annual Meeting 2023, in Orlando, Florida. This presentation also included clinical data from the dose 
optimization cohort evaluating petosemtamab monotherapy 1500 or 1100 mg dose levels in 2L+ HNSCC. As of the July 5, 
2024 data cutoff date, 82 previously treated HNSCC pts were treated with petosemtamab 1500 mg intravenously every two weeks. 
The efficacy population consists of 75 pts who had the opportunity for 4 or more months follow up and ≥1 post-baseline tumor 
assessment; or who discontinued early due to disease progression or death. Seven pts were not efficacy evaluable: 6 pts previously 
described at AACR 2023 (5 pts withdrew due to IRR on day 1 and 1 pt with exclusion criteria deviation) and 1 additional pt 
withdrew due to IRR on day 1. Confirmed overall response rate (ORR) was 36% (90% CI: 27–46; 27/75) by RECIST v1.1. per 
investigator assessment, including 4 CRs, with one CR continuing on treatment for more than 3 years as of the data cutoff. 
Responses were also reported in HPV associated cancer, ORR was 13% (2/15) and 5 additional pts achieved stable disease. At the 
time of data cutoff, 10 pts remained on treatment including 8 responders and 2 pts with stable disease. Median duration of response 
(DOR), progression free survival (PFS) and overall survival (OS) were 6.2, 4.9 and 11.4 months. For the most mature data set, the 
single arm cohort previously presented at AACR 2023, as of a July 5, 2024 data cutoff, for all 54 patients, the median DOR, PFS 
and OS were 6.7, 5.1, and 12.0 months, respectively and among the 48 treatment evaluable subset, they were 6.7, 5.2, and 12.5 
months, respectively. In 82 pts, petosemtamab 1500 mg every two weeks continues to be well tolerated with a manageable safety 
profile with no new safety signals observed. IRRs were predominantly seen on day 1 of cycle 1 and a clinically meaningful 
reduction in the incidence and severity of IRR was observed with an updated administration regimen compared to that used as of the 
2023 AACR presentation.
In July 2024, the first patient was dosed in a phase 2 trial evaluating petosemtamab in combination with standard chemotherapy in 
second line (2L) metastatic colorectal cancer (mCRC) and in December 2024 the first patient was dosed in a phase 2 trial evaluating 
petosemtamab monotherapy in heavily pretreated (3L+) mCRC. We have also started dosing patients in a cohort evaluated 
petosemtamab in combination with standard chemotherapy in 1L mCRC. We plan to present initial clinical data on the investigation 
of petosemtamab in mCRC in the second half of 2025.
In August 2023, the FDA granted Fast Track designation for the investigation of petosemtamab for the treatment of patients with 
recurrent or metastatic HNSCC whose disease has progressed following treatment with platinum-based chemotherapy and an anti-
programmed cell death protein 1 (anti-PD-1) antibody.  Fast Track is a designation designed to facilitate the development and expedite 
the review of drugs to treat serious conditions and fill unmet medical needs.
In May 2024, the FDA also granted BTD for petosemtamab for the treatment of patients with r/m HNSCC whose disease has 
progressed following treatment with platinum based chemotherapy and an anti-programmed cell death receptor-1 (PD-1) or anti-
programmed death ligand 1 (PD-L1) antibody. 
In February 2025, the FDA granted a second BTD for petosemtamab in combination with pembrolizumab for the first-line treatment 
of adult patients with r/m PD-L1 positive HNSCC with CPS ≥ 1.
Zenocutuzumab, or “Zeno” (MCLA-128: HER3 x HER2 Biclonics®): NRG1 gene fusion (NRG1+) cancers and other solid tumors 
BIZENGRI® (zenocutuzumab-zbco), obtained FDA accelerated approval as the first and only treatment indicated for adults with 
pancreatic adenocarcinoma or NSCLC that are advanced unresectable or metastatic and harbor a neuregulin 1 (NRG1) gene fusion 
who have disease progression on or after prior systemic therapy.
In December 2024, we entered into a license agreement with Partner Therapeutics, Inc. (PTx), a private, fully-integrated 
biotechnology company with a focus in hematology and oncology, in which we exclusively licensed to PTx the right to commercialize 
zenocutuzumab (Zeno) for the treatment of NRG1 fusion-positive (NRG1+) cancer in the United States (U.S.).
We are conducting ongoing translational work on potential biomarkers outside of NRG1+ cancer and other potential development 
opportunities, which may support investigation of Zeno in additional areas of unmet need beyond NRG1+ cancer.   
MCLA-129 (EGFR x c-MET Biclonics®): Solid Tumors
Investigation of MCLA-129 continues in MET ex14 NSCLC expansion cohort in the phase 1/2 trial; MCLA-129 in combination with 
chemotherapy in 2L+ EGFR mutant (EGFRm) NSCLC is ongoing.
MCLA-129 is in clinical development in a global, phase 1, open-label, clinical trial evaluating MCLA-129 in patients with c-MET 
exon 14 skipping mutations (METex14), and we continue to monitor and evaluate patients on treatment. 

103
We are also enrolling patients in the phase 2 trial evaluating MCLA-129 in combination with chemotherapy in 2L+ EGFRm NSCLC, 
with a cohort receiving MCLA-129 and paclitaxel and carboplatin, and another cohort receiving MCLA-129 and docetaxel. 
We remain interested in exploring partnering MCLA-129 to sufficiently resource the development of MCLA-129 and the potential 
benefit it may have for patients.  
MCLA-129 is subject to a collaboration and license agreement with Betta Pharmaceuticals Co. Ltd. (Betta), which permits Betta to 
develop MCLA-129 and potentially commercialize exclusively in China, while we retain global rights outside of China. 
Collaborations and Other Revenue Generating Agreements
Refer to Item 1, “Business—Collaboration Agreements,” and Note 12, “Collaborations,” of the notes to our Consolidated Financial 
Statements included elsewhere in this Annual Report on Form 10-K for a description of the key terms of our arrangements. 
Results of Operations for the Years Ended December 31, 2024 and 2023 
Revenue 
The following is a comparison of collaboration revenue for the years ended December 31, 2024 and 2023:
2024
Change
%
2023
(in thousands)
Incyte
$
22,659
$
(6,365)
-21.9%
$
29,024
Lilly
6,467
(8,400)
-56.5%
14,867
Gilead
4,800
4,800
100.0%
-
Partner Therapeutics
-
-
0.0%
-
Other
2,207
2,151
3841.1%
56
Total collaboration revenue
$
36,133
$
(7,814)
-17.8%
$
43,947
Our revenue from each collaborator consists of revenue recognized from the amortization of deferred revenue related to upfront 
payments for licenses or options to obtain licenses in the future, research and development services reimbursement revenue earned and 
milestone payments earned under collaboration and license agreements with our collaboration partners.
Collaboration revenue for the year ended December 31, 2024 decreased $7.8 million as compared to the year ended December 31, 
2023, primarily as a result of decreases in Lilly revenue of $8.4 million and Incyte revenue of $6.4 million, offset by increases in 
Gilead revenue of $4.8 million, and Other revenue of 2.2 million. The decrease in Lilly revenue is primarily the result of decreases in 
upfront payment amortization of $4.8 million and reimbursement revenue of $3.6 million. The decrease in Incyte revenue is primarily 
the result of decreases in milestone revenue of $5.0 million and reimbursement revenue of $1.4 million. Gilead revenue increased due 
to the start of the collaboration agreement in 2024 which resulted in an increase in upfront payment amortization of $4.8 million. The 
increase in Other revenue is primarily the result of increases in milestone revenue of $2.1 million.
As of December 31, 2024, we had total deferred revenue of $69.4 million, which primarily relates to the upfront payments received 
under our Gilead collaboration agreement and our Incyte collaboration agreement. The remaining deferred revenue of $51.3 million 
from the Gilead collaboration agreement is expected to be recognized over time using an output method of progress toward the 
development of the program target. The remaining deferred revenue of $17.6 million from the Incyte collaboration agreement is 
expected to be recognized over the next two years. 
Operating Expenses
The following is a comparison of operating expenses for the years ended December 31, 2024 and 2023:
2024
Change
%
2023
(in thousands)
Research and development
$
225,368
$
84,710
60.2%
$
140,658
General and administrative
82,832
22,996
38.4%
59,836
Total operating expenses
$
308,200
$ 107,706
53.7%
$
200,494

104
Research and Development Expense
Research and development costs consist principally of the costs associated with our research and development activities, conducting 
pre-clinical studies and clinical trials, and activities related to our regulatory filings. Our research and development expenses consist 
of:
•
salaries for research and development staff and related expenses, including share-based compensation expenses;
•
expenses incurred under agreements with contract research organizations (CROs), contract manufacturing organizations, 
and consultants that conduct and support clinical trials and pre-clinical studies;
•
costs to enhance our platform technologies, develop product candidates, including raw materials and supplies, product 
testing, and facility related expenses; and
•
amortization and depreciation of tangible and intangible fixed assets used to develop our product candidates.
Note that we do not allocate employee-related costs, depreciation, rental and other indirect costs to specific research and development 
programs because these costs are deployed across multiple programs under research and development and, as such, are separately 
classified as unallocated research and development expenses.
The following table summarizes our research and development expenses by product candidate for the twelve months ended 
December 31, 2024 and 2023:
For the twelve months ended December 31,
2024
2023
Change
(in thousands)
Research and development expenses
Petosemtamab - MCLA-158
$
104,406
$
31,795
$
72,611
Zenocutuzumab - MCLA-128
32,831
$
28,807
4,024
MCLA - 129
15,751
18,109
(2,358)
Research general
10,079
15,935
(5,856)
Total Program Costs
$
163,067
$
94,646
$
68,421
R&D Employee-Related Expenses - Unallocated
45,373
33,576
11,797
Other Indirect R&D Expenses - Unallocated
16,928
12,436
4,492
Total Research and development expenses
$
225,368
$
140,658
$
84,710
The following table summarizes our research and development expenses by type for the twelve months ended December 31, 2024 and 
2023:
For the twelve months ended December 31,
2024
2023
Change
(in thousands)
Research and development expenses
External and manufacturing and other external costs
$
157,597
$
90,806
$
66,791
Wages, salaries and other employee benefits
22,664
21,983
681
Share-based compensation
22,709
11,593
11,116
Consultants
12,208
6,692
5,516
Depreciation and amortization
1,104
1,154
(50)
Facilities and other related
9,086
8,430
656
Total research and development expenses
$
225,368
$
140,658
$
84,710
Research and development expense for the year ended December 31, 2024 increased $84.7 million as compared to the year ended 
December 31, 2023, primarily as a result of increases in external clinical services and drug manufacturing costs of $66.6 million, 
which includes costs to advance our research pipeline and costs to fulfill our obligations under our collaboration agreements related to 
our programs, increases in personnel related expenses including share-based compensation of $11.8 million due to an increase in 
employee headcount and an increase in share price, consultancy expenses of $5.5 million, facilities expenses and other related 
expenses of $0.7 million, and consumables expenses of $0.2 million, offset by decreases in depreciation and amortization of $0.1 
million. 

105
Research and development activities are central to our business model. We expect to continue to incur significant research and 
development costs for the foreseeable future as we continue to enhance our platform technologies, our development programs 
progress, as we continue to support the clinical trials of our antibody candidates as treatments for various cancers and as we move 
these candidates into additional clinical trials. There are numerous factors associated with the successful commercialization of any of 
our antibody candidates, including future trial design and various regulatory requirements, many of which cannot be determined with 
accuracy at this time based on our stage of development. Additionally, future commercial and regulatory factors beyond our control 
may impact our clinical development programs and plans.
General and Administrative Expense
General and administrative expenses consist primarily of salaries and related benefits, including share-based compensation, related to 
our executive, finance, legal and intellectual property, business development and support functions. Other 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. 
General and administrative expense for the year ended December 31, 2024 increased $23.0 million as compared to the year ended 
December 31, 2023, primarily as a result of increases in personnel related expenses including share-based compensation of $12.6 
million due to an increase in employee headcount and an increase in share price, consultancy expenses of $6.8 million, legal expenses 
of $1.8 million, facilities and depreciation expense of $1.2 million, and intellectual property and licenses expenses of $0.7 million, 
partially offset by decreases in finance and human resources expenses of $0.1 million.
We expect general and administrative expenses to increase as we grow as a company, driven by the need to support a growing 
workforce, engaging in financing transactions, establishing and maintaining our intellectual property rights, fulfilling our compliance 
requirements as a public company and related legal, regulatory and potential commercialization costs.
Other Income, Net
The following is a comparison of other income, net, for the years ended December 31, 2024 and 2023:
2024
Change
%
2023
(in thousands)
Interest (expense) income, net
$
30,789
$
16,279
112.2%
$
14,510
Foreign exchange (losses) gains, net
34,103
43,813
-451.2%
(9,710)
Total other income (loss), net
$
64,892
$
60,092
1251.9%
$
4,800
Other income (loss), net consists of interest earned on our cash and cash equivalents held on account, accretion of investment earnings 
and net foreign exchange gains or losses on our foreign denominated cash, cash equivalents, marketable securities, and payables and 
receivables. 
Income Tax Expense 
The following is a comparison of income tax expense for the years ended December 31, 2024 and 2023:
2024
Change
%
2023
(in thousands)
Current
$
8,472
$
6,122
260.5% $
2,350
Deferred
(321)
(1,163)
-138.1%
842
Income tax expense
$
8,151
$
4,959
155.4% $
3,192
We are subject to income taxes in the Netherlands and the U.S. Our current and deferred tax provision represents taxable income 
attributed to our U.S. operations as a consequence of allocating income to that jurisdiction. No current or deferred provision for 
income taxes has been made for income taxes in the Netherlands due to losses for tax purposes. Further, given a history of losses in 
the Netherlands, no deferred tax assets in excess of deferred tax liabilities are recognized as it is not more likely than not that they will 
be recovered.
Income tax expense increased primarily due to an increase in book income before tax and an increase in permanent differences due to 
increases in stock option exercises. 

106
Net Loss
Net loss for the year ended December 31, 2024 was $215.3 million, compared to $154.9 million for the year ended December 31, 
2023. The change in net loss of $60.4 million was primarily due to the changes in collaboration revenue, changes in operating 
expenses, and changes in other income, net, as discussed above.. 
Liquidity and Capital Resources 
Cash requirements
We require external sources of financing to fund our operations. Since inception through December 31, 2024, we have raised an 
aggregate of $1,674.9 million, of which $221.8 million was non-equity funding through our collaboration agreements, $1,342.4 
million was from the sale of common shares and $110.7 million was from private funding sources prior to our initial public offering. 
These amounts include aggregate immediate proceeds from the closing of the collaboration and license agreement and share purchase 
agreement with Eli Lilly in January 2021 of $60.0 million, the aggregate net proceeds from the January 2021 follow-on offering of 
$129.4 million, the aggregate net proceeds from the November 2021 follow-on offering of $118.7 million, the aggregate net proceeds 
during the years ended December 31, 2022 and 2023 from the "at the market" offering program pursuant to an Open Market Sale 
Agreement (the 2021 Sales Agreement) with Jefferies LLC of $57.7 million and $63.8 million, respectively, [A1] [A2] the aggregate net 
proceeds from the August 2023 underwriting agreement with Jefferies LLC, BofA Securities, Inc., Guggenheim Securities, LLC and 
William Blair & Company, L.L.C., as representatives of the several underwriters named therein, of $162.2 million, aggregate net 
proceeds from the closing of the Gilead collaboration agreement in March 2024 of $81.0 million, and the aggregate net proceeds from 
the May 2024 underwriting agreement with Jefferies LLC, BofA Securities, Inc., Leerink Partners LLC, Guggenheim Securities, LLC 
and BMO Capital Markets Corp., as representatives of the several underwriters named therein, of $434.9 million. As of December 31, 
2024, we had $724.0 million in cash, cash equivalents and marketable securities that are available to fund our current and future 
operations.
In February 2024, we entered into an Open Market Sale Agreement (the “2024 Sales Agreement”) with Jefferies LLC ("Jefferies") to 
sell from time to time up to $300 million of our common shares through an “at-the-market” offering program under which Jefferies 
acts as the sales agent. Subject to the terms and conditions of the 2024 Sales Agreement, Jefferies can sell the common shares by any 
method deemed to be an “at-the-market” offering as defined in Rule 415 promulgated under the Securities Act. There have been no 
sales under the 2024 Sales Agreement through December 31, 2024. 
On March 5, 2024, we entered into a collaboration, option and license agreement (“Gilead Collaboration Agreement”) and Share 
Subscription Agreement (the “Gilead Subscription Agreement”) with Gilead Sciences, Inc. (“Gilead”). Under the terms of the Gilead 
Collaboration Agreement, we and Gilead agreed to collaborate on the use of Merus’ proprietary Triclonics® platform to develop 
certain trispecific T-cell engaging multi-specific antibody products for the treatment of certain indications. The collaboration shall 
include at least two, but may include up to three, separate preclinical research programs (each, a “Program”) for the design and 
validation of candidates directed to the applicable program targets selected by Gilead. On a Program-by-Program basis, we have 
granted Gilead an exclusive option to obtain an exclusive license for such Program. If Gilead exercises the license option with respect 
to a Program, Gilead will be responsible for the development and commercialization of the products arising from such Program. 
Gilead paid an upfront, non-refundable payment of $56.0 million for the rights granted under the Gilead Collaboration Agreement. If 
Gilead exercises its option to an additional Program, we will receive an initiation fee of $28.0 million. If Gilead exercises its license 
option for all Programs, we will receive up to a total of approximately $1.5 billion across all three programs. We are further eligible to 
receive, with respect to all products arising from a Program, if approved, and country-by-country basis, tiered royalties based on the 
level of worldwide aggregate annual net sales at percentages ranging from the mid-single digits to low double digits until the royalty 
term expires, subject to customary reductions. We also have an option to forego unachieved development milestones and royalties to 
enter into a 50/50 split of net profits and net losses arrangement for the third program upon a specified time period triggered by the 
first investigational new drug application filing for the third Program. In connection with entering into the Gilead Collaboration 
Agreement, pursuant to the Gilead Subscription Agreement, Gilead purchased 452,527 common shares of the Company at a price per 
share of $55.2454 for aggregate gross proceeds to us of approximately $25.0 million. Gilead agreed not to transfer, sell, or otherwise 
dispose of such shares for a period of time following the purchase of the shares, subject to certain customary exceptions. 
On May 29, 2024, the Company entered into an underwriting agreement (the “2024 Underwriting Agreement”) with Jefferies, BofA 
Securities, Inc., Leerink Partners LLC, Guggenheim Securities, LLC and BMO Capital Markets Corp., as representatives of the 
several underwriters named therein (collectively, the “2024 Underwriters”), in connection with the issuance and sale by us in a public 
offering of 7,550,000 common shares of the Company, nominal value €0.09 per share, at a public offering price of $53.00 per share, 
less underwriting discounts and commissions, pursuant to an effective shelf registration statement on Form S-3 and accompanying 
prospectus (Registration No. 333-277465), which became effective upon filing on February 28, 2024, and a prospectus supplement 
thereunder. Under the terms of the 2024 Underwriting Agreement, we also granted the 2024 Underwriters an option exercisable for 30 
days to purchase up to an additional 1,132,500 common shares at the public offering price, less underwriting discounts and 
commissions. On May 30, 2024, the 2024 Underwriters exercised this option in full. The offering closed on May 31, 2024, and we 
received net proceeds of $434.9 million, after deducting underwriting discounts and commissions.

107
In addition to our existing cash, cash equivalents and marketable securities, we may receive research and development co-funding and 
are eligible to earn a significant amount of milestone payments under our collaboration agreements. Our ability to earn these payments 
and the timing of earning these payments is dependent upon the outcome of our research and development activities and is uncertain at 
this time. Our collaboration and license agreements may require payment of milestones to third parties contingent on future events.
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, collaboration arrangements, licensing, other business development opportunities and government grants. 
Except for any obligations of our collaborators to make license, milestone or royalty payments under our agreements with them, and 
government grants, 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 shareholders may 
be diluted, and the terms of these securities may include liquidation or other preferences that adversely affect the rights of our existing 
common shareholders. 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. If we raise additional funds through collaboration arrangements, licensing or other business development opportunities in 
the future, we may have to relinquish valuable rights to our technologies or intellectual property, 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 candidate development or future commercialization efforts or grant rights to develop 
and market product candidates that we would otherwise prefer to develop and market ourselves. 
Our primary uses of capital are: clinical trial costs, third-party research and development services, personnel, laboratory and related 
supplies, legal, intellectual property and other regulatory expenses and general overhead costs. Because our product candidates are in 
various stages of clinical and pre-clinical development and the outcome of these efforts is uncertain, we cannot estimate the actual 
amounts necessary to successfully complete the development and commercialization of our product candidates or whether, or when, 
we may achieve profitability. In addition, our expenditures as reported in our financial statements may be expected to be variable due 
to that uncertainty. We enter into contracts in the normal course of business with CROs for clinical and pre-clinical research studies, 
external manufacturers for product candidates 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 are not contractual 
obligations. Our material contractual obligations, if any, are described elsewhere in this Annual Report on Form 10-K, including Notes 
9 and 10 of the attached Consolidated Financial Statements. 
Based on our current operating plan, research and development plans and our timing expectations related to the progress of our 
programs, we expect that our existing cash, cash equivalents and marketable securities as of December 31, 2024, will be sufficient to 
fund our planned operating expenses and capital expenditure requirements into 2028. We have based this estimate on assumptions that 
may prove to be wrong, particularly as the process of testing product 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 December 31, 2024 and 2023:
 
2024
Change
%
2023
(in thousands)
Net cash used in operating activities
$
(185,835)
$ (43,628)
31%
$
(142,207)
Net cash provided by (used in) investing activities
$
(220,222)
$ (193,202)
715%
$
(27,020)
Net cash provided by financing activities
$
494,008
$ 263,922
115%
$
230,086
Operating Activities 
Net cash used in operating activities for the year ended December 31, 2024 increased $43.6 million as compared to the year ended 
December 31, 2023 primarily as a result of increases in cash outflows related to operating expenses of $102.3 million, partially offset 
by increases in cash inflows from collaboration arrangements (upfront payments, milestones, and research and development 
reimbursements) of $50.3 million, and cash inflows from Other Income of $8.4 million.
Investing Activities 
Net cash used in investing activities during the year ended December 31, 2024 increased by $193.2 million as compared to the year 
ended December 31, 2023, primarily due to increases in purchases of marketable securities of $174.9 million, decreases in proceeds 

108
from maturities of marketable securities of $20.4 million, and increases in purchases of intangible assets of $0.2 million, partially 
offset by decreases in purchases of property and equipment of $2.3 million.
Financing Activities 
Net cash provided by financing activities during the year ended December 31, 2024 increased by $263.9 million as compared to the 
year ended December 31, 2023, primarily due to higher proceeds received from issuance of common stock in 2024 from the 2024 
Underwriting Agreement of $434.9 million compared to the aggregate proceeds received in 2023 from the 2021 Sales Agreement with 
Jefferies of $63.8 million and the 2023 Underwriting Agreement of $162.2 million, an increase in proceeds received from the Gilead 
collaboration agreement of $22.6 million and an increase in proceeds from share option exercises of $32.3 million.
Cash Management
Our objective in managing our cash resources (cash, cash equivalents, and marketable securities) is to safeguard Merus’ ability to 
continue as a going concern and to minimize the cost of capital to provide returns for shareholders and benefits for other stakeholders. 
Once we receive a source of financing, our cash resources are invested to preserve capital as a primary goal, and to derive some return 
as a secondary consideration. Cash and cash equivalents include deposits and investments held with financial institutions with an 
original maturity date of less than three months. Marketable securities include commercial paper, securities issued by several public 
corporations and the U.S. Treasury with a maturity date of greater than three months at the date of settlement. Cash and cash 
equivalents are held at banks and financial institutions with credit ratings varying between A and AAA, while investments are in 
highly rated vehicles with similar credit ratings.
Our invested cash resources are deployed to achieve our operating objectives in furthering our programs. 
Critical Accounting Policies and Estimates 
Our accounting policies are more fully described in Note 2 to our Consolidated Financial Statements included elsewhere in the Annual 
Report on Form 10-K. As disclosed in Note 2, the preparation of financial statements in conformity with generally accepted 
accounting principles requires management to make estimates and assumptions about future events that affect the amounts reported in 
the financial statements and accompanying notes. Actual results could differ significantly from those estimates. We believe that the 
following discussion addresses our most critical accounting policies and estimates, which are those that are most important to the 
portrayal of our financial condition and results of operations and require management’s most difficult, subjective and complex 
judgments on material matters. 
Revenue Recognition 
Significant judgment is required in applying our accounting policies concerning revenue recognition. Our collaboration arrangements 
may be subject to the scope of many accounting standards in addition to the standards applicable to revenue from contracts with 
customers, including whether all or part of the arrangement may be a collaboration arrangement as defined in the accounting standards 
or whether financial instruments exchanged in the same arrangement may be subject to other guidance. Such matters may impact the 
initial recognition, subsequent accounting and disclosures concerning the arrangement. 
Our collaboration arrangements typically include a license to our intellectual property and significant judgment is applied at the outset 
of the arrangement in determining whether the particular license is distinct from other performance obligations in the arrangement. We 
consider whether the counterparty may be able to utilize the license in the absence of the provision of other performance obligations 
by us. Each collaboration features unique terms to a license and the provision of other performance obligations also varies. Such 
considerations impact the timing of recognition of consideration allocated to performance obligations.
A key judgment in the application of our revenue recognition policy concerns the method of recognition of revenue over time as 
performance obligations are completed. Methods may include an input-based, output-based or other rational allocation method. 
Furthermore, estimates of progress towards satisfaction of performance obligations are often derived from expectations on the 
outcome of research and development activities which are subject to uncertainty. 
Changes in these estimates of progress impact the timing of revenue recognition. These estimates have not materially changed in the 
current period presented in our Consolidated Financial Statements. For example, with respect to the license and related activities 
performance obligation of the Incyte collaboration arrangement recognized as revenue over time as access to the platform for the 
generation of potential product candidates is provided to the customer, an increase of one year in the estimate as of January 1, 2024 
would have decreased revenue recognized for the year ended December 31, 2024 by approximately $5.8 million, excluding the effects 
of foreign exchange translation.
Other Accounting Policies, Judgments, and Estimates

109
Going Concern
Our evaluation of our ability to continue as a going concern requires us to evaluate our future sources and uses of cash sufficient to 
fund our currently expected operations in conducting research and development activities one year from the date our financial 
statements are issued. We evaluate the probability associated with each source and use of cash resources in making our going concern 
determination. The research and development of pharmaceutical products is inherently subject to uncertainty.
Recent Accounting Pronouncements 
For a discussion of pending and recently adopted accounting pronouncements, see Note 2 to our Consolidated Financial Statements 
included elsewhere in this Annual Report on Form 10-K.
Item 7A. Quantitative and Qualitative Disclosures About Market Risk. 
We are exposed to market risk from changes in interest rates, foreign exchange rates and inflation. All of these market risks arise in 
the ordinary course of business, as we do not engage in speculative trading activities. The following analysis provides additional 
information regarding these risks.
Interest Rate Risk
Our investments in marketable securities, which consist of corporate paper and notes, U.S. government securities and treasury notes, 
are subject to interest rate risk. As of December 31, 2024, marketable securities were $430.7 million. As of December 31, 2023, 
marketable securities were $207.4 million. Due to the conservative and short-term nature of these investments in our portfolio, an 
immediate 10% change in market interest rates would not have a material impact on the fair market value of our investment portfolio 
or on our financial position or results of operations for either year. We had no outstanding debt that is subject to interest rate risk as of 
December 31, 2024 or December 31, 2023.
Foreign Currency and Exchange Risk
Merus US, Inc.’s functional currency is the U.S. dollar. The functional currency of Merus N.V. is the euro. Our revenues and 
monetary assets and liabilities are mainly denominated in U.S. dollars. A significant portion of our operating costs are in the 
Netherlands, which are denominated in the euro. This foreign currency exposure gives rise to market risk associated with exchange 
rate movements of the U.S. dollar against the euro. Furthermore, we anticipate that a significant portion of our expenses will continue 
to be denominated in the euro. A hypothetical 15% weakening of the U.S. dollar compared to the euro would have increased our net 
loss for the year ended December 31, 2024, by approximately $35.0 million and increased our currency translation adjustment by 
approximately $36.9 million. A hypothetical 15% strengthening of the U.S. dollar compared to the euro would have an equal and 
opposite effect on our financial statements. A hypothetical 15% weakening of the U.S. dollar compared to the euro would have 
increased our net loss for the year ended December 31, 2023, by approximately $24.5 million and increased our currency translation 
adjustment by approximately $66.1 million. A hypothetical 15% strengthening of the U.S. dollar compared to the euro would have an 
equal and opposite effect on our financial statements.  
Impact of Inflation
While it is difficult to accurately measure the impact of inflation due to the imprecise nature of the estimates required, we do not 
believe inflation has had a material effect on our historical results of operations and financial condition. However, if our costs were to 
become subject to significant inflationary pressures, we may not be able to fully offset higher costs through raising funds or other 
corrective measures, and our inability or failure to do so could adversely affect our business, financial condition, and results of 
operations.
Item 8. Financial Statements and Supplementary Data. 
The financial statements required to be filed pursuant to this Item 8 are included in this Annual Report on Form 10-K. An index of 
those financial statements is found in Item 15 of Part IV of this Annual Report on Form 10-K. 
Item 9. Changes in and Disagreements with Accountants on Accounting and Financial Disclosure 
None. 

110
Item 9A. Controls and Procedures 
Limitations on Effectiveness of Controls and Procedures
In designing and evaluating our disclosure controls and procedures, management recognizes that any controls and procedures, no 
matter how well designed and operated, can provide only reasonable assurance of achieving the desired control objectives. In addition, 
the design of disclosure controls and procedures must reflect the fact that there are resource constraints and that management is 
required to apply judgment in evaluating the benefits of possible controls and procedures relative to their costs.
Evaluation of Disclosure Controls and Procedures
Our management, with the participation of our principal executive and financial officer, has evaluated, as of the end of the period 
covered by this Annual Report on Form 10-K, the effectiveness of our disclosure controls and procedures (as defined in Rules 13a-
15(e) and 15d-15(e) under the Exchange Act). Based on such evaluation, our principal executive and principal financial officer 
concluded that our disclosure controls and procedures were effective at the reasonable assurance level as of December 31, 2024.
Management’s Annual Report on Internal Control over Financial Reporting
Our management is responsible for establishing and maintaining adequate internal control over our financial reporting, as such term is 
defined in Rule 13a-15(f) under the Exchange Act. Our management conducted an assessment of the effectiveness of our internal 
control over financial reporting based on the criteria set forth in “Internal Control - Integrated Framework (2013)” issued by the 
Committee of Sponsoring Organizations of the Treadway Commission. Based on this assessment, our management concluded that, as 
of December 31, 2024, our internal control over financial reporting was effective.
The effectiveness of our internal control over financial reporting as of December 31, 2024 has been audited by KPMG Accountants 
N.V., an independent registered public accounting firm, as stated in their report, which is included in this Annual Report on Form 10-
K in Part IV, Item 15. 
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) identified in management’s evaluation pursuant to Rules 13a-15(d) or 15d-15(d) of the Exchange Act that occurred 
during the quarter ended December 31, 2024 that materially affected, or are reasonably likely to materially affect, our internal control 
over financial reporting.
Item 9B. Other Information.
(b) Insider Trading Arrangements and Policies
During the three months ended December 31, 2024, no director or "officer" (as defined in Rule 16a-1(f) under the Exchange Act) of 
the Company adopted or terminated a “Rule 10b5-1 trading arrangement” or “non-Rule 10b5-1 trading arrangement,” as each term is 
defined in Item 408(a) of Regulation S-K.
Item 9C. Disclosure Regarding Foreign Jurisdictions that Prevent Inspections.
Not applicable.

111
PART III
Item 10. Directors, Executive Officers and Corporate Governance. 
Director Biographical Information
Anand Mehra, M.D., age 49, has served as a non-executive director since August 2015 and as Chairperson of our board of directors 
effective since June 2020. Dr. Mehra held various positions at Sofinnova Investments (f.k.a. Sofinnova Ventures) from 2007 to 
January 2020, most recently holding the position of a managing general partner, where he focused on working with entrepreneurs to 
build drug development companies. He led the firm’s investments in Vicept Therapeutics (acquired by Allergan), Aerie 
Pharmaceuticals, Inc., Aclaris Therapeutics, Inc. (Aclaris), and Spark Therapeutics. Prior to joining Sofinnova, Dr. Mehra worked in 
J.P. Morgan’s private equity and venture capital group and as a consultant at McKinsey & Company. He currently serves as a member 
of the board of directors of the publicly held life science company Aclaris. Within the past five years, he also served on the boards of 
directors of the publicly held life science companies Marinus Pharmaceuticals, Inc., Spark Therapeutics, Inc. and Aerie 
Pharmaceuticals. Dr. Mehra received a B.A. degree in political philosophy from the University of Virginia and an M.D. degree from 
Columbia University’s College of Physicians and Surgeons. We believe that Dr. Mehra’s extensive experience in the life science 
industry, his service on the board of directors of other publicly held life science companies and his extensive leadership experience 
qualify him to serve on our board of directors.
Maxine Gowen, Ph.D., age 66, has served as a non--executive director of our board of directors since May 2021. Dr. Gowen was the 
founding President and Chief Executive Officer of Trevena, Inc. (Trevena), from 2007 to October 2018. Prior to this position, Dr. 
Gowen held a variety of leadership roles at GlaxoSmithKline (GSK) over a period of 15 years. As Senior Vice President for the 
company’s Center of Excellence for Drug Discovery, she developed an innovative new approach to externalizing drug discovery. Dr. 
Gowen was previously President and Managing Partner at SR One, the venture capital subsidiary of GSK, where she led its 
investments in and served on the boards of directors of numerous companies. Dr. Gowen also previously served as Vice President, 
Drug Discovery, Musculoskeletal Diseases at GSK, where she was responsible for drug discovery and early development for 
osteoporosis, arthritis and metastatic bone disease. Dr. Gowen currently serves on the boards of directors of publicly held life science 
companies Aclaris, and Passage Bio, and served on the boards of directors of publicly held life science companies Aceragen, Inc., 
Akebia Therapeutics (Akebia), Idera Therapeutics, and Trevena. Dr. Gowen holds a B.Sc. in biochemistry from the University of 
Bristol, U.K., received a Ph.D. in cell biology from the University of Sheffield, U.K., and received an M.B.A. from the Wharton 
School of the University of Pennsylvania. We believe that Dr. Gowen is qualified to serve on our board of directors due to her 
leadership, experience in the biotechnology industry and in the field of clinical drug development, her scientific experience and her 
tenure as CEO and independent director at several publicly held life science companies. 
Mark Iwicki, age 58, has served as a non-executive director of our board of directors since June 2015. From June 2015 until July 
2018, Mr. Iwicki served as the Chairperson of our board of directors. Mr. Iwicki currently serves as Chief Executive Officer of 
Inhibikase Therapeutics, Inc., since February 2025, the Chairperson of Kala BIO, Inc., since September 2015 and served as Chief 
Executive Officer of Kala BIO, Inc., from September 2015 to February 2025. From February 2014 to November 2014 Mr. Iwicki 
served as President and Chief Executive Officer of Civitas Therapeutics. From December 2012 to January 2014, Mr. Iwicki served as 
President and Chief Executive Officer and director at Blend Therapeutics, Inc. From 2007 to June 2012, Mr. Iwicki served in several 
roles, including Chief Commercial Officer, President and Chief Operating Officer and Director and Chief Executive Officer at 
Sunovion Pharmaceuticals, Inc., formerly Sepracor, Inc., a pharmaceutical company. From 1998 to 2007, Mr. Iwicki held executive 
positions, including Vice President and Business Unit Head, at Novartis Pharmaceuticals Corporation, a pharmaceutical company. Mr. 
Iwicki currently serves on the boards of directors of publicly held life science companies Akero Therapeutics, Inc. Third Harmonic 
Bio, Inc., Q32 Bio, Inc. and Kala BIO, Inc. Within the past five years, he also served on the board of directors of the publicly held life 
science company Aimmune Therapeutics Inc. and Pulmatrix, Inc. Mr. Iwicki received a B.A. in business administration from Ball 
State University and an M.B.A. from Loyola University. We believe that Mr. Iwicki is qualified to serve on our board of directors due 
to his leadership, commercial and business experience in the biotechnology industry and breadth of knowledge about our business, as 
well as his tenure as CEO and independent director in several publicly held life science companies.
Len Kanavy, age 64, has served as a non-executive director of our board of directors since July 2018. Mr. Kanavy most recently 
served as Senior Vice President, Commercial Business Operations at Genentech, a biotechnology company, from September 2006 to 
September 2016, where he was responsible for strategic decisions for the U.S. commercial business, including product launches, 
valuation of business development opportunities, clinical development plan options and pricing. From 2014 to 2016, he was a board 
member of the Genentech Access to Care Foundation. Prior to joining Genentech, Mr. Kanavy was Vice President, Commercial 
Operations at Novartis Pharmaceuticals, where he led teams in business analytics, strategy, and product launches. Mr. Kanavy holds a 
B.S. in Business Administration and an M.B.A. with a specialization in Finance from the University of Scranton. We believe that Mr. 
Kanavy is qualified to serve on our board of directors due to his leadership, business development and commercial experience in the 
biotechnology industry.

112
Jason Haddock, age 52, has served as a non-executive director of our board of directors since May 2024. Mr. Haddock has more than 
20 years of financial and operational experience in the biopharmaceutical industry and currently serves as a director of PYC 
Therapeutics since May 2021 and formerly served on the board of directors of Codiak Biosciences from August 2020 to June2023. 
Mr. Haddock also served as Chief Financial Officer at Archer Dx from May to August 2020 until it was acquired by Invitae 
Corporation. Prior to that, Mr. Haddock served as CFO of Array BioPharma, Inc., from 2016 to 2019, where he was responsible for 
execution of an oncology-focused research, development and  commercialization strategy. Prior to that, from 2015 to 2016, he served 
as Chief Financial Officer and Chief Operating Officer of BERG, an artificial intelligence-based analytics biopharma company, and 
from 2001to 2015, at Bristol-Myers Squibb in a variety of finance, strategic, commercial and business development capacities, 
including Chief Financial Officer and Chief Operating Officer roles for business units in Asia Pacific, Europe and the United States. 
He holds a BS in accounting from Illinois State University and an Executive MBA from Washington University in St.Louis. We 
believe that Mr. Haddock is qualified to serve on our board of directors due to his leadership,international business and biotechnology 
experience as well as his operational, financial planning and accounting experience and expertise.
Bill Lundberg, M.D., age 61, has served as a non--executive of our board of directors from June 2019 to December 2019, and as an 
executive director since December 2019. Since December 2019, Dr. Lundberg has served as our President, Chief Executive Officer 
and Principal Financial Officer. From January 2015 to February 2018, Dr. Lundberg was Chief Scientific Officer of CRISPR 
Therapeutics AG (CRISPR), a biotechnology company, where he was responsible for establishing and growing research and 
development in the United States and oversaw CRISPR’s first CRISPR-based product from inception to regulatory filing for clinical 
trials. From February 2011 to January 2015, Dr. Lundberg was Vice President and Head of Translational Medicine at Alexion 
Pharmaceuticals, Inc. (Alexion), where he oversaw research and development from discovery through early-stage development, and 
prior to that, he was Director and Chief Medical Officer of Taligen Therapeutics, Inc. (Taligen), a biotechnology company, which was 
acquired by Alexion in 2011. Prior to Taligen, he held roles of increasing responsibility in clinical drug development and medical 
affairs at Xanthus/Antisoma, Wyeth (now Pfizer), and Genzyme. Dr. Lundberg currently serves on the board of directors of the 
publicly traded life science companies Vor Biopharma and Q32 Bio Inc. Dr. Lundberg received an M.D. from Stanford University and 
M.B.A. from the University of Massachusetts. He completed post-doctoral training at the Whitehead Institute/M.I.T., and clinical 
training in Medicine and Medical Oncology from Harvard and the Dana-Farber Cancer Institute. We believe that Dr. Lundberg is 
qualified to serve on our board of directors due to his experience in the field of medicine, clinical drug development, scientific 
experience, leadership and business experience.
Paolo Pucci, age 63, has served as a non-executive director of our board of directors since June 2020. Mr. Pucci served as the Chief 
Executive Officer of ArQule, Inc. (ArQule), a biopharmaceutical oncology company engaged in the research and development of 
targeted therapeutics, from June 2008 until its acquisition by Merck Inc. in January 2020. Prior to joining ArQule, Mr. Pucci worked 
at Bayer AG from 2001 to 2008, where he served in a number of leadership capacities including President of the Oncology & Global 
Specialty Medicines Business Units and was a member of the Bayer Pharmaceuticals Global Management Committee. Before Bayer, 
Mr. Pucci held positions of increasing responsibility with Eli Lilly and Company from July 1991 to April 2001, culminating with his 
appointment as Managing Director, Eli Lilly Sweden AB. Mr. Pucci earned an M.S. in economics and accounting from Università 
degli Study di Napoli Federico II and an M.B.A. in marketing and finance from the University of Chicago. Within the past five years, 
Mr. Pucci previously served on the boards of directors of Algeta ASA, until its acquisition by Bayer AG, and Dyax Inc., until its 
acquisition by Shire Plc (which was subsequently acquired by Takeda Pharmaceutical Company Ltd.), New Link Genetics Inc, 
ArQule Inc., until its acquisition by Merck Inc., and Trillium Therapeutics Inc., until its acquisition by Pfizer Inc. He currently serves 
on the boards of directors of publicly held life sciences companies West Pharmaceuticals Services, Inc., and Replimmune Group Inc. 
We believe that Mr. Pucci is qualified to serve on our board of directors due to his leadership, international business and 
biotechnology experience in large multinational pharmaceutical corporations as well as his tenure as CEO and independent director in 
several publicly held life science companies, and breadth of knowledge about our business.
Victor Sandor, M.D.C.M., age 58, has served as a non-executive director of our board of directors since June 2019. From September 
2014 to December 2019, Dr. Sandor was the Chief Medical Officer at Array BioPharma (Array), a pharmaceutical company, where he 
oversaw clinical development through regulatory approval of Braftovi® and Mektovi® for the treatment of BRAFV600E/K mutant 
melanoma and Braftovi for the treatment of BRAFV600E mutant colorectal cancer. Prior to joining Array, from February 2010 to 
September 2014, he was Senior Vice President for Global Clinical Development at Incyte Corporation (Incyte), a pharmaceutical 
company, where he oversaw clinical development through regulatory approval of Jakafi® for the treatment of myelofibrosis and 
polycythemia vera. Prior to joining Incyte, Dr. Sandor was Vice President and Chief Medical Officer for oncology at Biogen Idec and, 
prior to that held positions of increasing responsibility in oncology product development at AstraZeneca, where he played a lead role 
in the registration of Arimidex® (anastrozole) for adjuvant use and the development of early stage programs through proof-of-concept. 
Dr. Sandor received his M.D.C.M. from McGill University in Montreal, Canada, and completed his Fellowship in Medical Oncology 
at the National Institutes of Health in Bethesda, Maryland. He currently serves on the boards of directors of publicly held life sciences 
companies ADC Therapeutics, Prelude Therapeutics and Kymera Therapeutics. We believe that Dr. Sandor is qualified to serve on our 
board of directors due to his experience in the field of medicine, clinical drug development and scientific experience and breadth of 
knowledge about our business.

113
Information About Our Executive Officers
Bill Lundberg, M.D., age 61, see biography under "Director Biographical Information".
Peter B. Silverman, J.D., age 47, has served the Company since 2014, first as outside counsel, as Chief Operating Officer since 
January 1, 2023, as Head of Utrecht from April 2020 to January 1, 2023, as General Counsel since February 2018 and our Chief 
Intellectual Property Officer and Head of US Legal since February 2017. His responsibilities include management of the Company’s 
operations, including clinical operations, business strategy, non-clinical development and supply, legal and intellectual property, and 
information technology departments. Prior to joining Merus, Mr. Silverman was a Partner at Kirkland & Ellis LLP, where he 
represented numerous life sciences companies concerning an array of legal matters and technologies. Mr. Silverman was an associate 
at Kaye Scholer LLP (now Arnold & Porter Kaye Scholer LLP), and prior to that Mr. Silverman also served as judicial law clerk to 
U.S. District Court Judge Anne E. Thompson of the District of New Jersey. He holds a J.D. from Fordham University School of Law, 
graduating magna cum laude and Order of the Coif. He is admitted to practice law in New York. Mr. Silverman also holds a B.A. in 
biology from the University of Rochester.
Greg Perry, age 64, has served as a non-executive director of our board of directors since May 2016 and Vice Chairperson of our 
board of directors since August 2018. Since June 2023, Mr. Perry has served as our Chief Financial Officer (CFO).  His 
responsibilities include serving as the Principal Financial Officer, and overseeing the finance and quality functions of our 
organization. From May 2018 until his retirement in April 2022, Mr. Perry served as the CFO at Finch Therapeutics Group. Mr. Perry 
served as the Chief Financial and Administrative Officer of Novelion Therapeutics Inc. from November 2016 to December 2017. Prior 
to Novelion, Mr. Perry was CFO of Aegerion Pharmaceuticals Inc. from July 2015 until its merger with Novelion in November 2016. 
He has also served as CFO of several additional biotechnology companies, and earlier in his career he held various financial 
leadership roles within ImmunoGen, Domantis Ltd., Transkaryotic Therapeutics, Honeywell and General Electric. Mr. Perry currently 
serves on the board of directors of Kala Pharmaceuticals. Mr. Perry received a B.A. in Economics and Political Science from Amherst 
College.
Fabian Zohren, M.D., Ph.D., age 49, has served as our Chief Medical Officer since July 2024. His responsibilities include leading 
clinical development at Merus. Dr. Zohren previously served as Chief Medical Officer at lmmunoGen from November 2023 through 
its acquisition by AbbVie in May 2024, and worked on the transition of ImmunoGen into AbbVie thereafter. Prior to lmmunoGen, Dr. 
Zohren worked at Pfizer from 2017 until 2023 where he most recently served as Global Clinical Development Leader for prostate 
cancer and DNA repair, a role which included Xtandi® (enzalutamide) and Talzenna® (talazoparib) with oversight of two clinical 
programs encompassing >8000 treated patients and 8 global phase 3 registrational studies in prostate and breast cancer. Earlier in his 
career at Pfizer, he was the Senior Medical Director and Global Clinical Leader for prostate cancer and gynecological malignancies. 
He joined Pfizer from Millennium Pharmaceuticals/Takeda where he was the Senior Medical Director and Early Clinical 
Development Leader for their Cell Signaling Franchise since 2012. Dr. Zohren received his Medical Degree and Ph.D. from the 
University of Dusseldorf and was a research scholar at Baylor College of Medicine in the Center for Cell and Gene Therapy.
Code of Ethics
We have adopted a Code of Business Conduct and Ethics for all of our directors, officers and employees, including our principal 
executive officer, principal financial officer, principal accounting officer or controller, or persons performing similar functions. We 
have posted a current copy of our Code of Business Conduct and Ethics on our website at www.merus.nl in the “Investors & Media” 
section under “Corporate Governance.” We intend to satisfy the disclosure requirement under Item 5.05 of Form 8-K regarding 
amendment to, or waiver from, a provision of our Code of Business Conduct and Ethics, as well as Nasdaq’s requirement to disclose 
waivers with respect to directors and executive officers, by posting such information on our website at the address and location 
specified above. The information contained on our website is not incorporated by reference into this Annual Report on Form 10-K.
Insider Trading Policies and Procedures
We have adopted an Insider Trading Compliance Policy, which applies to all of our directors, officers, employees and other covered 
persons, governing the purchase, sale, and other dispositions of our securities. We believe our Insider Trading Compliance Policy and 
procedures are reasonably designed to promote compliance with insider trading laws, rules and regulations, and listing standards 
applicable to the Company. A copy of our Insider Trading Compliance Policy is filed with this Annual Report on Form 10-K as 
Exhibit 19.1.
Other
The remaining information required by this Item 10 will be included in our definitive Proxy Statement for the 2025 Annual Meeting of 
Shareholders.

114
Item 11. Executive Compensation. 
The information required by this Item 11 will be included in our definitive Proxy Statement for the 2025 Annual Meeting of 
Shareholders. 
Item 12. Security Ownership of Certain Beneficial Owners and Management and Related Shareholder Matters. 
The information required by this Item 12 will be included in our definitive Proxy Statement for the 2025 Annual Meeting of 
Shareholders. 
Item 13. Certain Relationships and Related Transactions, and Director Independence. 
The information required by this Item 13 will be included in our definitive Proxy Statement for the 2025 Annual Meeting of 
Shareholders.
Item 14. Principal Accounting Fees and Services. 
The information required by this Item 14 will be included in our definitive Proxy Statement for the 2025 Annual Meeting of 
Shareholders.

115
PART IV
Item 15. Exhibits, and Financial Statement Schedules. 
(a)
1.
Financial Statements.
The following Report and Consolidated Financial Statements of the Company are included in this Annual Report on 
Form 10-K:
 
Index to Consolidated Financial Statements
Page
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 Shareholders’ Equity ......................................................................................................................
F-7
Notes to Consolidated Financial Statements ...............................................................................................................................
F-8
2.
Financial Statements and Schedules.
All financial statement 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.
The following is a list of exhibits filed as part of this Annual Report on Form 10-K.

116
 
 
 
Incorporated by Reference to
Filings Indicated
 
Exhibit
Number
 
Exhibit Description
 Form
 
File No.
 
Exhibit
No.
 
Filing
Date
 
Filed/
Furnished
Articles of Association and By-Laws
3.1
 
Articles of Association of Merus N.V., as amended 
on July 29, 2024
 
10-Q
 
001-37773
 
3.1
 
8/1/24
 
Instruments Defining the Rights of Security 
Holders
4.1
Description of Securities
*
Material Contracts – Management Contracts and 
Compensation Plans
10.1.1
 
Merus N.V. 2016 Incentive Award Plan Amended 
and Restated May 7, 2024
 
 
*
10.1.2
 
Merus N.V. Non-Executive Director Compensation 
Program
 
10-Q
001-37773
10.1
8/6/20
 
10.1.3
 
Form of Board of Directors Indemnification 
Agreement
 
F-1/A
 
333-207490
 
10.4
 
5/9/16
 
10.1.4
Employment Agreement, dated January 1, 2023, by 
and between Merus US, Inc. and Peter Silverman
8-K
001-37773
10.1
1/6/23
10.1.5
Employment Agreement, dated January 1, 2019, by 
and among Merus US, Inc., the Registrant and Sven 
A. Lundberg
10-K
001-37773
10.1.13
3/16/20
10.1.6
Employment Agreement, dated as of June 14, 2023, 
by and between Merus US, Inc. and Gregory Perry
8-K
001-37773
10.1
6/15/23
10.1.7
Employment Agreement by and between Merus US, 
Inc. and Fabian Zohren.
8-K
001-37773
10.1
7/1/2024
10.1.8
Employment Agreement, dated July 2, 2020, by and 
among Merus US, Inc., the Registrant and Andrew 
Joe
10-Q
001-37773
10.4
8/6/20
10.1.9
Consulting Agreement, dated April 15, 2024 
between Victor Sandor and Merus US, Inc.
10-Q
001-37773
10.2
5/8/24

117
 
 
 
Incorporated by Reference to
Filings Indicated
 
Exhibit
Number
 
Exhibit Description
 
Form
 
File No.
 
Exhibit
No.
 
Filing
Date
 
Filed/
Furnished
Material Contracts – Banking and Financing
10.2.1
 
English language translation of Loan Agreement 
between the Registrant and Coöperatieve Rabobank 
Utrechtse Heuvelrug U.A., dated December 29, 2005  
F-1
 
333-207490
 
10.8
 
10/19/15
 
10.2.2
 
English language translation of letter amendment, 
dated October 21, 2015, to Loan Agreement between 
the Registrant and Coöperatieve Rabobank Utrechtse 
Heuvelrug U.A.
 
F-1/A
 
333-207490
 
10.9
 
1/21/16
 
10.2.3
 
English language translation of letter amendment, 
dated March 15, 2016, to Loan Agreement between 
the Registrant and Coöperatieve Rabobank Utrechtse 
Heuvelrug U.A.
 
F-1/A
 
333-207490
 
10.9.1
 
5/9/16
 
10.2.4
 
English language translation of letter amendment, 
dated March 15, 2016, to Loan Agreement between 
the Registrant and Coöperatieve Rabobank Utrechtse 
Heuvelrug U.A.
 
F-1/A
 
333-207490
 
10.9.2
 
5/9/16
 
Material Contracts – Leases
10.3.1
English translation of Lease for Office Space and 
Other Commercial Space, dated July 2019, by and 
between Kadans Science Partner XIII B.V. and Merus 
N.V.
10-Q
001-37773
10.1
5/9/22
10.3.2
English translation of Addendum a, dated April 11, 
2022, to Lease for Office Space and Other 
Commercial Space, dated July 19, 2019, by and 
between Kadans Science Partner XIII B.V. and Merus 
N.V.
10-Q
001-37773
10.2
5/9/22
Material Contracts – Collaboration and License 
Agreements
10.4.1†
 
Collaboration and License Agreement, dated 
December 20, 2016, by and between the Registrant 
and Incyte Corporation
 
20-F
 
001-37773
 
4.12
 
4/28/17
 
 
 
 
Incorporated by Reference to
Filings Indicated
 
Exhibit
Number
 
Exhibit Description
 
Form
 
File No.
 
Exhibit
No.
 
Filing
Date
 
Filed/
Furnished
10.4.2†††
Contract Research and License Agreement and 
Addendum between the Registrant and Ono 
Pharmaceutical Co., Ltd., dated April 8, 2014
10-Q
001-37773
10.3.5
11/2/21
10.4.3†
 
Contract Research and License Agreement by and 
between the Registrant and Ono Pharmaceutical Co., 
Ltd., dated March 14, 2018
 
20-F
 
001-37773
 
4.19
 
4/30/18
 
10.4.4††
Collaboration and License Agreement, dated January 
18, 2021, by and between the Registrant and Eli Lilly 
and Company
10-K
001-37773
10.4.5
3/16/21

118
10.4.5†
Collaboration, Option and License Agreement, dated 
as of March 5, 2024, by and between Merus N.V. and 
Gilead Sciences, Inc.
10-Q
0001-37773
10.1
5/8/24
10.4.6†
License Agreement by and between Merus N.V. and 
Partner Therapeutics, Inc. dated November 27, 2024
*
Other Exhibits
21.1
List of Subsidiaries
F-1/A
333-207490
21.1
4/8/16
23.1
Consent of Independent Registered Public 
Accounting firm
*
31.1
Certification of Principal Executive Officer pursuant 
to rules 13a-14(a) and 15d-14(a) under the Securities 
and Exchange Act of 1934, as adopted pursuant to 
Section 302 of the Sarbanes-Oxley Act of 2002
*
31.2
Certification of Principal Financial Officer pursuant 
to rules 13a-14(a) and 15d-14(a) under the Securities 
and Exchange Act of 1934, as adopted pursuant to 
Section 302 of the Sarbanes-Oxley Act of 2002
*
32.1
Certification of Principal Executive Officer and 
Principal Financial Officer Pursuant to 18 U.S.C. 
1350, as adopted pursuant to Section 906 of the 
Sarbanes-Oxley Act of 2002
**
97.1
Compensation Recovery Policy
10-K
001-37773
97.1
2/28/24
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 With 
Embedded Linkbase Documents
*
104
Cover Page Interactive Data File (formatted as Inline 
XBRL and contained in Exhibit 101).
*
*
Filed herewith.
**
Furnished herewith.
†
Confidential treatment granted as to portions of the exhibit. Confidential materials omitted and filed separately with the 
Securities and Exchange Commission.
††
Portions of the exhibit have been omitted. Certain identified information has been excluded from the exhibit because it is both (i) 
not material and (ii) would be competitively harmful if publicly disclosed.
††† Portions of the exhibit have been omitted. Certain identified information has been excluded from the exhibit because it is both (i) 
not material and (ii) the type that the Registrant treats as private or confidential.
Item 16. Form 10-K Summary.
None.

119
SIGNATURES
Pursuant to the requirements of Section 13 or 15(d) of the Securities Exchange Act of 1934, as amended, the Registrant has duly 
caused this Report to be signed on its behalf by the undersigned, thereunto duly authorized.
MERUS N.V.
Date: February 27, 2025
By: /s/ Sven A. Lundberg
Sven (Bill) Ante Lundberg
President, Chief Executive Officer and 
Principal Executive Officer
Pursuant to the requirements of the Securities Exchange Act of 1934, as amended, this Report has been signed below by the following 
persons on behalf of the Registrant in the capacities and on the dates indicated.
Name
Title
Date
 
 
 
/s/ Sven A. Lundberg
President, Chief Executive Officer, 
Principal Executive Officer and Director
February 27, 2025
Sven (Bill) Ante Lundberg
 
/s/ Gregory D. Perry
Chief Financial Officer, 
Principal Financial Officer and Director
February 27, 2025
Gregory D. Perry
 
/s/ Harry Shuman
Chief Accounting Officer, Principal Accounting Officer
February 27, 2025
Harry Shuman
 
/s/ Anand Mehra
Chairman of the Board of Directors
February 27, 2025
Anand Mehra
 
/s/ Len Kanavy
Director
February 27, 2025
Len Kanavy
/s/ Mark T. Iwicki
Director
February 27, 2025
Mark T. Iwicki
 
/s/ Paolo Pucci
Director
February 27, 2025
Paolo Pucci
 
/s/ Victor Sandor
Director
February 27, 2025
Victor Sandor
 
/s/ Maxine Gowen
Director
February 27, 2025
Maxine Gowen
/s/ Jason Haddock
Director
February 27, 2025
Jason Haddock
 

F-1
MERUS N.V.
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 Shareholders’ Equity .........................................................................................................................
F-7
Notes to Consolidated Financial Statements .................................................................................................................................
F-8

F-2
Report of Independent Registered Public Accounting Firm
To the Shareholders and Board of Directors of Merus N.V.:
Opinions on the Consolidated Financial Statements and Internal Control Over Financial Reporting 
We have audited the accompanying consolidated balance sheets of Merus N.V. and subsidiary (the Company) as of 
December 31, 2024 and 2023, the related consolidated statements of operations and comprehensive loss, cash flows, 
and shareholders’ equity for each of the years in the three-year period ended December 31, 2024 and the related notes 
(collectively, the consolidated financial statements). We also have audited the Company’s internal control over financial 
reporting as of December 31, 2024, based on criteria established in Internal Control – Integrated Framework (2013) 
issued by the Committee of Sponsoring Organizations of the Treadway Commission.  
In our opinion, the consolidated financial statements referred to above present fairly, in all material respects, the financial 
position of the Company as of December 31, 2024 and 2023, and the results of its operations and its cash flows for each 
of the years in the three-year period ended December 31, 2024, in conformity with U.S. generally accepted accounting 
principles. Also in our opinion, the Company maintained, in all material respects, effective internal control over financial 
reporting as of December 31, 2024 based on criteria established in Internal Control – Integrated Framework (2013) issued 
by the Committee of Sponsoring Organizations of the Treadway Commission.
Basis for Opinions 
The Company’s management is responsible for these consolidated financial statements, 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 consolidated financial statements and an opinion on the 
Company’s internal control over financial reporting based on our audits. We are a public accounting firm registered with 
the Public Company Accounting Oversight Board (United States) (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 audits to obtain reasonable assurance about whether the consolidated financial statements are free of 
material misstatement, whether due to error or fraud, and whether effective internal control over financial reporting was 
maintained in all material respects. 
Our audits of the consolidated financial statements included performing procedures to assess the risks of material 
misstatement of the consolidated 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 consolidated 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 consolidated 
financial statements. Our audit of internal control over financial reporting included obtaining an understanding of internal 
control over financial reporting, assessing the risk that a material weakness exists, and testing and evaluating the design 
and operating effectiveness of internal control based on the assessed risk. Our audits also included performing such other 
procedures as we considered necessary in the circumstances. We believe that our audits provide a reasonable basis for 
our opinions.
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.

F-3
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.
Critical Audit Matter
The critical audit matter communicated below is a matter arising from the current period audit of the consolidated 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 consolidated financial statements and (2) involved our especially 
challenging, subjective, or complex judgments. The communication of a 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.
Identification of distinct performance obligations 
As discussed in Note 12 to the consolidated financial statements, the Company entered into a collaboration, option and 
license agreement with Gilead Sciences, Inc. (“Gilead”). The fixed consideration of $58.4 million was allocated equally 
between the Program #1 and Program #2 License and Research performance obligations, respectively.  
We identified the evaluation of the distinct performance obligations identified by the Company as a critical audit matter. 
Complex auditor judgment was required in evaluating the terms and conditions in the collaboration, option and license 
agreement with Gilead to assess the identification of distinct performance obligations.   
The following are the primary procedures we performed to address this critical audit matter:
- We evaluated the design and tested the operating effectiveness of an internal control related to the Company’s revenue 
recognition process, including the identification of distinct performance obligations; and
- We obtained and read the collaboration, option and license agreement with Gilead and evaluated the terms and 
conditions to assess that the performance obligations within the agreement were identified in accordance with relevant 
accounting guidance. 
/s/ KPMG Accountants N.V.
We have served as the Company’s auditor since 2009. 
Amstelveen, the Netherlands
February 27, 2025

F-4
MERUS N.V.
CONSOLIDATED BALANCE SHEETS 
(Amounts in thousands, except share and per share data) 
2024
2023
ASSETS
Current assets:
Cash and cash equivalents
$
293,294
$
204,246
Marketable securities
243,733
150,130
Accounts receivable
1,261
2,429
Prepaid expenses and other current assets
30,784
12,009
Total current assets
569,072
368,814
Marketable securities
187,008
57,312
Property and equipment, net
10,770
12,135
Operating lease right-of-use assets
9,254
11,362
Intangible assets, net
1,679
1,800
Deferred tax assets
1,520
1,199
Other assets
3,390
2,872
Total assets
$
782,693
$
455,494
LIABILITIES AND SHAREHOLDERS’ EQUITY
Current liabilities:
Accounts payable
$
4,164
$
4,602
Accrued expenses and other liabilities
43,957
38,482
Income taxes payable
7,317
1,646
Current portion of lease obligation
1,704
1,674
Current portion of deferred revenue
29,934
22,685
Total current liabilities
87,076
69,089
Lease obligation
8,208
10,488
Deferred revenue, net of current portion
39,482
19,574
Total liabilities
134,766
99,151
Commitments and contingencies (Note 10)
Shareholders’ equity:
Common shares, €0.09 par value; 105,000,000 and 67,500,000 shares authorized at 
December 31, 2024 and 2023, respectively; 68,828,749 and 57,825,879 shares issued 
and outstanding at December 31, 2024 and 2023, respectively
6,957
5,883
Additional paid-in capital
1,664,822
1,126,054
Accumulated deficit
(968,387)
(753,061)
Accumulated other comprehensive (loss) income
(55,465)
(22,533)
Total shareholders’ equity
647,927
356,343
Total liabilities and shareholders’ equity
$
782,693
$
455,494
See notes to consolidated financial statements. 

F-5
MERUS N.V.
CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS 
(Amounts in thousands, except share and except per share data) 
Year Ended December 31,
2024
2023
2022
Collaboration revenue
$
36,133
43,947
41,586
Total revenue
36,133
43,947
41,586
Operating expenses:
Research and development
225,368
140,658
149,424
General and administrative
82,832
59,836
52,200
Total operating expenses
308,200
200,494
201,624
 
Operating loss
(272,067)
(156,547)
(160,038)
Other income (loss), net:
Interest (expense) income, net
30,789
14,510
2,722
Foreign exchange (losses) gains, net
34,103
(9,710)
26,022
Other (losses) gains, net
—
—
1,059
Total other income (loss), net
64,892
4,800
29,803
 
Loss before income tax expense
(207,175)
(151,747)
(130,235)
Income tax expense
8,151
3,192
959
Net loss
$
(215,326)
$
(154,939)
$
(131,194)
Other comprehensive income (loss):
Currency translation adjustment
(32,932)
7,915
(21,227)
Comprehensive loss
$
(248,258)
$
(147,024)
$
(152,421)
Net loss per share allocable to common shareholders:
Basic and diluted
$
(3.35)
$
(3.00)
$
(2.92)
Weighted-average common shares outstanding:
Basic and diluted
64,220,765
51,605,444
44,919,084
See notes to consolidated financial statements. 

F-6
MERUS N.V.
CONSOLIDATED STATEMENTS OF CASH FLOWS 
(Amounts in thousands) 
 
Year Ended December 31,
2024
2023
2022
CASH FLOWS FROM OPERATING ACTIVITIES:
Net loss
$
(215,326)
$
(154,939)
$
(131,194)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation of property and equipment
2,294
2,325
981
Amortization of intangible assets
177
215
304
Foreign exchange losses (gains)
(38,345)
13,951
(23,528)
Share-based compensation expense
45,834
26,226
24,535
Amortization (accretion) of discount on investments
(4,463)
(5,074)
(407)
Deferred tax benefit
(321)
842
(1,624)
Changes in operating assets and liabilities:
Accounts receivable
1,070
1,726
1,831
Operating lease right-of-use assets and lease obligations
(101)
(84)
815
Prepaid expenses and other current assets
(20,970)
2,648
(7,344)
Accounts payable
(136)
(3,931)
(3,920)
Accrued expenses and other liabilities
13,404
1,615
15,648
Deferred revenue
31,048
(27,727)
(25,996)
Net cash used in operating activities
(185,835)
(142,207)
(149,899)
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of marketable securities
(410,190)
(235,263)
(219,725)
Proceeds from maturities of marketable securities
191,798
212,225
230,166
Purchases of intangible assets
(163)
—
(52)
Purchases of property and equipment
(1,667)
(3,982)
(7,587)
Net cash provided by (used in) investing activities
(220,222)
(27,020)
2,802
CASH FLOWS FROM FINANCING ACTIVITIES:
Payment of offering costs
(325)
(445)
(214)
Proceeds from issuance of common shares, net
434,863
225,945
57,740
Proceeds from issuance of common shares - Gilead Collaboration
22,613
—
—
Proceeds from share options exercised
36,857
4,586
1,213
Net cash provided by financing activities
494,008
230,086
58,739
Foreign exchange impact on cash, cash equivalents and restricted cash
1,066
(4,284)
(4,952)
Net increase (decrease) in cash, cash equivalents and restricted cash
89,017
56,575
(93,310)
Cash, cash equivalents, and restricted cash, beginning of period
205,014
148,439
241,749
Cash, cash equivalents, and restricted cash, end of period
$
294,031
$
205,014
$
148,439
SUPPLEMENTAL DISCLOSURES:
Lease liabilities arising from obtaining right-of-use assets
$
—
$
—
$
11,493
Income taxes paid
$
2,800
$
3,103
$
—
Non-cash purchases of property, equipment and intangibles
$
—
$
42
$
2,093
CASH, CASH EQUIVALENTS AND RESTRICTED CASH
Cash and cash equivalents
$
293,294
$
204,246
$
147,749
Restricted cash included in other assets
737
768
690
$
294,031
$
205,014
$
148,439
See notes to consolidated financial statements. 

F-7
MERUS N.V.
CONSOLIDATED STATEMENTS OF SHAREHOLDERS’ EQUITY 
(Amounts in thousands, except share data) 
Common Shares
Additional
Paid-In
Accumulated
Accumulated
Other
Comprehensive
Total
Shareholders’
Shares
Amount
Capital
Deficit
(Loss) Income
Equity
Balance at December 31, 2021
43,467,052
$
4,481
$
787,869
$
(466,928)
$
(9,221)
$
316,201
Issuance of common stock in connection with public offerings, net of 
underwriting discounts and commissions and offering costs
2,720,846
258
57,269
—
—
57,527
Exercise of stock options and vesting of restricted stock units
122,691
12
1,201
—
—
1,213
Share-based compensation
—
—
24,535
—
—
24,535
Currency translation adjustment
—
—
—
—
(21,227)
(21,227)
Net loss
—
—
—
(131,194)
—
(131,194)
Balance at December 31, 2022
46,310,589
$
4,751
$
870,874
$
(598,122)
$
(30,448)
$
247,055
Issuance of common shares in connection with public offerings, net of 
underwriting discounts and commissions and offering costs
11,113,189
1,093
224,407
—
—
225,500
Exercise of share options and vesting of restricted share units
402,101
39
4,547
—
—
4,586
Share-based compensation
—
—
26,226
—
—
26,226
Currency translation adjustment
—
—
—
—
7,915
7,915
Net loss
—
—
—
(154,939)
—
(154,939)
Balance at December 31, 2023
57,825,879
$
5,883
$
1,126,054
$
(753,061)
$
(22,533)
$
356,343
Issuance of common share - Gilead
452,527
45
22,568
—
—
22,613
Issuance of common share in connection with public offerings, net of 
underwriting discounts and commissions and offering costs
8,682,500
848
433,690
—
—
434,538
Exercise of share options and vesting of restricted share units
1,867,843
181
36,676
—
—
36,857
Share-based compensation
—
—
45,834
—
—
45,834
Currency translation adjustment
—
—
—
—
(32,932)
(32,932)
Net loss
—
—
—
(215,326)
—
(215,326)
Balance at December 31, 2024
68,828,749
$
6,957
$
1,664,822
$
(968,387)
$
(55,465)
$
647,927
See notes to consolidated financial statements. 

F-8
MERUS N.V.
NOTES TO CONSOLIDATED FINANCIAL STATEMENTS 
1. The Company 
Merus N.V. is an oncology company developing innovative antibody therapeutics, headquartered in Utrecht, the Netherlands. Merus 
US, Inc. is a wholly-owned subsidiary of Merus N.V. located at 139 Main Street, Cambridge, Massachusetts, United States 
(collectively, the “Company”).
Since inception, the Company has generated an accumulated deficit of $968.4 million as of December 31, 2024. The Company 
expects to continue to incur significant expenses and operating losses for the foreseeable future as its antibody candidates advance 
through discovery, pre-clinical development and clinical trials and as it seeks regulatory approval and pursues commercialization of 
any approved antibody candidate.
As a result, the Company may need additional financing to support its continuing operations. Until the Company can generate 
significant revenue from product sales, if ever, the Company expects to finance its operations through public equity offerings, debt 
financings, or other sources, which may include collaborations, business development and licensing opportunities with third parties. 
Adequate additional financing may not be available to the Company on acceptable terms, or at all. The Company’s inability to raise 
capital as and when needed would have a negative impact on its financial condition and ability to pursue its business strategy. The 
Company will need to generate significant revenues to achieve profitability and may never do so.
2. Summary of Significant Accounting Policies 
Basis of Preparation
The Company prepared its consolidated financial statements in compliance with generally accepted accounting principles in the U.S. 
("U.S. GAAP"). Any reference in these notes to applicable guidance is meant to refer to authoritative U.S. GAAP as found in the 
Accounting Standards Codification ("ASC") and Accounting Standards Update ("ASU") of the Financial Accounting Standards Board 
("FASB"). 
Principles of Consolidation 
Subsidiaries are entities controlled by the Company, consisting of Merus N.V.’s wholly owned subsidiary Merus US, Inc. The 
Company controls an entity when it is exposed to, or has rights to, variable returns from its involvement with the entity and has the 
ability to affect those returns through its power over the entity. The financial statements of subsidiaries are included in the 
consolidated financial statements from the date on which control commences until the date on which control ceases. All significant 
intercompany balances and transactions have been eliminated in consolidation.
Functional and Presentation Currency
Items recorded in each of the Company’s entities are measured using the currency of the primary economic environment in which the 
entity operates (the "functional currency"). Merus US, Inc.’s functional currency is the U.S. dollar. The functional currency of Merus 
N.V. is the euro. After measuring foreign currency denominated transactions into an entity’s functional currency, to the extent that a 
subsidiary’s functional currency differs from its parent, a subsidiary’s financial position and results of operations are translated into its 
parent’s functional currency. The Company’s consolidated financial position and results of operations are translated into the U.S. 
dollar as the Company’s reporting currency.
Use of Estimates 
The preparation of these consolidated financial statements in accordance with U.S. GAAP 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 collaboration revenue and expenses during the 
reporting period. Actual results and outcomes may differ materially from management’s estimates, judgments and assumptions. 
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. 

F-9
Accounts receivable represent amounts due from 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. 
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. 
Fair Value Measurements
Fair value is defined as an exit price, representing the amount that would be received upon the sale of an asset or payment to transfer a 
liability in an orderly transaction between market participants. Fair value is a market-based measurement that is determined based on 
assumptions that market participants would use in pricing an asset or liability. A three-tier fair value hierarchy is used to prioritize the 
inputs in measuring fair value as follows:
•
Level 1 – Quoted market prices (unadjusted) in active markets for identical assets or liabilities that the reporting entity has 
the ability to access at the measurement date. 
•
Level 2 – Quoted market prices for similar assets or liabilities in active markets, quoted prices for identical or similar assets 
or liabilities in markets that are not active, or other inputs that are observable, either directly or indirectly. Fair value 
determined through the use of models or other valuation methodologies.
•
Level 3 – Significant unobservable inputs for assets or liabilities that cannot be corroborated by market data. Fair value is 
determined by the reporting entity’s own assumptions utilizing the best information available and includes situations where 
there is little market activity for the asset or liability. 
The asset’s or liability’s fair value measurement within the fair value hierarchy is based upon the lowest level of any input that is 
significant to the fair value measurement. 
The Company considers its cash, cash equivalents, accounts receivable, marketable securities due with maturities 12 months or less, 
and accounts payable financial instruments to reflect their fair value given their short maturity and risk profile of the counterparty.
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 and it 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 the current cash, cash equivalent and marketable security balances. After considering the 
Company’s current research and development plans and the timing expectations related to the progress of its clinical-stage programs 
and its plans to pursue commercialization of any antibody candidate, if approved, and after considering its existing cash, cash 
equivalents and marketable securities as of December 31, 2024, the Company 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.  
Cash and Cash Equivalents 
The Company considers all highly liquid debt securities with original final maturities of three months or less from the date of purchase 
to be cash equivalents. Instruments subject to restrictions are not included in cash and cash equivalents.
Restricted Cash
The Company maintains certain cash balances restricted to withdrawal or use. Restricted cash includes cash held as collateral for 
certain contractual agreements and is recorded in other assets in the consolidated balance sheets.

F-10
Marketable Securities 
The Company classifies marketable securities that are debt securities with a remaining maturity when purchased of greater than three 
months as held-to-maturity as the Company has the positive intent and ability to hold such debt securities through maturity. 
Debt securities that are classified as held-to-maturity are initially recognized and measured at fair value. Subsequent to initial 
recognition, they are measured at amortized cost. Interest income from these debt securities is included in interest income. Marketable 
securities are classified as current if their expected maturity is within one year or less of the balance sheet date and non-current if their 
maturity is beyond one year of the balance sheet date.
Accounts Receivable 
Accounts receivable are amounts due from collaboration partners as a result of research and development services provided or 
milestones achieved but not yet paid.
Allowance for Credit Losses
The Company evaluates its cash equivalents, accounts receivable and held-to-maturity marketable securities financial assets for 
expected credit losses. Expected credit losses represent the portion of the amortized cost basis of a financial asset that an entity does 
not expect to collect. An allowance for expected credit losses is meant to reflect a risk of loss even if remote, irrespective of the 
expectation of collection from a particular issuer or debt security. The Company has not historically experienced any credit losses on 
any of its financial assets.
With respect to cash equivalents and accounts receivable, given consideration of their short maturity, lack of historical losses and the 
current environment, the Company concluded there is generally no expected credit losses for these financial assets. With respect to 
held-to-maturity marketable securities which are comprised of debt securities, the Company evaluates expected credit losses on a 
pooled basis based on issuer-type which have similar credit risk characteristics. The allowance for credit losses is immaterial for all 
periods presented.
Property and Equipment 
The Company records property and equipment at cost. The Company calculates depreciation and amortization using the straight-line 
method over the following estimated useful lives: 
Asset Category
Useful Lives
Laboratory equipment
5 years
Office furniture and equipment
5 years
Leasehold improvements
Shorter of term of lease or 10 years
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 or amortization, from the related accounts, and the resulting gain or loss is reflected in the results of 
operations. 
Intangible Assets 
Intangible assets are identifiable non-monetary assets without physical substance. An asset is a resource that is controlled by the 
enterprise as a result of past events (for example, purchase or self-creation) and from which future economic benefits (inflows of cash 
or other assets) are expected. The useful lives of intangible assets are assessed to be definite-lived and amortized over the useful 
economic life. The Company’s intangible assets are comprised of purchased licenses to intellectual property and software licenses. 
Impairment of Long-Lived Assets 
The Company reviews long-lived assets to be held and used, including property and equipment, operating lease right-of-use assets and 
definite-lived 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 first 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 in 2024, 2023 
or 2022. 

F-11
Leases
The Company determines if an arrangement is or contains a lease at inception. For leases with a term of 12 months or less, the 
Company does not recognize a right-of-use asset or lease liability. The Company does not have any finance leases.
Right-of-use assets represent the Company’s right to use an underlying asset for the lease term and lease liabilities represent the 
Company’s obligation to make lease payments arising from the lease, and excludes non-lease payments. Operating lease right-of-use 
assets and liabilities are recognized at the lease commencement date based on the present value of lease payments over the lease term. 
As the Company’s leases typically do not provide an implicit rate, the Company uses an estimate of its incremental borrowing rate 
based on the information available at the lease commencement date in determining the present value of lease payments. 
Operating lease right-of-use assets also include the effect of any lease payments made and excludes lease incentives. The lease terms 
may include options to extend or terminate the lease when it is reasonably certain that the Company will exercise that option. 
Operating lease expense is recognized on a straight-line basis over the lease term.
The Company has real estate operating lease agreements with lease and non-lease components, which are generally accounted for 
separately as operating lease costs and variable lease costs. Non-lease components in real estate leases refer to services provided by 
the lessor related to the premises. Fixed and variable lease payments are both allocated to lease and non-lease components. The 
allocation is determined on a relative fair value basis of the services provided relative to the operating lease of premises. With respect 
to equipment leases, the Company has elected not to allocate payments amongst lease and non-lease components as a practical 
expedient as afforded under ASC 842, Leases.
Income Taxes 
Deferred Taxes
The Company records deferred taxes to recognize the future effects of temporary differences between the tax basis and financial 
statement carrying amount of assets and liabilities. The Company measures the deferred taxes using enacted tax rates expected to 
apply 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, reversing taxable temporary differences and other relevant factors. The Company 
records changes in the required valuation allowance in the period that the determination is made. 
Unrecognized Tax Benefits
The Company assesses its income tax positions and records tax benefits for all years subject to examination based upon management’s 
evaluation of the technical merits, 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 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 an underpayment of 
income taxes, if applicable, as a component of income tax expense. 
Revenue Recognition 
The Company 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 an 
arrangement, the Company performs the following five step analysis: 
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 has entered into collaboration and license agreements, which are within the scope of ASC 606, Revenue from Contracts 
with Customers, 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 product candidates or future 
product candidates 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. 

F-12
As part of the accounting for these arrangements, the Company must use 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; 
c)
the stand-alone selling price for each performance obligation identified in the contract for the allocation of transaction price 
in step (iv) above;
d)
whether the combined performance obligation is satisfied over time or at a point in time in step (v) above; and 
e)
the appropriate method for measuring progress toward complete satisfaction of a performance obligation in step (v) above.
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. The Company recognizes variable consideration when the constraint has been resolved. Based on the nature of 
the variable consideration related to milestones, the Company allocates the variable amount (and subsequent changes to that amount) 
entirely to a performance obligation or to a distinct good or service that forms a part of a single performance obligation. 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 unbilled receivables.
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 rights and obligations set out in the contract, 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.
The Company’s arrangements may provide the collaboration partner with the right to select a target for licensing either at the 
inception of the arrangement or in the future. Under these arrangements, 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.

F-13
For arrangements that include sales-based milestones and royalties, 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 sales-based milestones or royalty revenue resulting from any of its arrangements.
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 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. The 
Company evaluates the measure of progress each reporting period as described under Exclusive Licenses above. 
Reimbursements from the partner are evaluated as to whether the Company acts as a principal or an agent in such relationships. The 
Company evaluates whether control over the underlying goods or services were obtained prior to transferring these goods or services 
to the collaboration partner. Where the Company does not control the goods or services prior to transferring these goods or services to 
the collaboration partner, such reimbursements are presented net of costs.
At the inception of each arrangement that includes development milestone payments in respect of development efforts, the Company 
evaluates whether the development 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 development milestone value is included in the transaction price. Development 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 development milestone in making this assessment. There is 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 re-evaluates the probability of achievement of all development 
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.
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. 
When third-party service providers’ billing terms do not coincide with the Company’s period-end, the Company is required to make 
estimates of its obligations to those third parties, 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 in conducting similar activities and the expected duration of the third-party service contract, among other considerations. 
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 vendors will exceed the level of services provided and result in a 
prepayment of research and development expenses. 
The WBSO (afdrachtvermindering speur- en ontwikkelingswerk) is a Dutch fiscal facility that provides subsidies to companies, 
knowledge centers and self-employed people who perform research and development activities (as defined in the WBSO Act). Under 
this act, a contribution is paid towards the labor costs of employees directly involved in research and development. For the years 
ended December 31, 2024, 2023 and 2022, the Company recognized $12.8 million, $5.9 million and $9.3 million as a reduction of 
research and development expenses, respectively.

F-14
Share-Based Compensation
The Company measures employee share-based compensation based on the grant date fair value of the share-based compensation 
award. The Company grants share options at exercise prices equal to the fair value of the Company’s common share on the date of 
grant, based on observable market prices. 
For share-based awards subject time-based vesting, the Company recognizes employee share-based compensation expense on a 
straight-line basis over the requisite service period of the awards, generally from the date of grant through each vesting date. The 
Company recognizes forfeitures at the time they occur. The actual expense recognized over the vesting period will only represent 
those options that vest; the effect of forfeitures in the recognition of periodic compensation expense are not estimated prior to their 
occurrence. 
Earnings (Loss) per Share 
Basic net loss per share is computed by dividing the net loss by the weighted average number of ordinary shares outstanding for the 
period. Diluted net loss is computed by adjusting net loss based on the potential impact of dilutive securities. Diluted net loss per share 
is computed by dividing the diluted net loss by the weighted average number of ordinary shares outstanding for the period, including 
potentially dilutive ordinary shares. For the purpose of this calculation, outstanding share options and unvested restricted share units 
are considered potential dilutive ordinary shares. Since the Company was in a loss position for all periods presented, the basic net loss 
per share is the same as diluted net loss per share for all periods as the inclusion of all potential ordinary share equivalents outstanding 
would have been anti-dilutive. 
The following securities, presented based on amounts outstanding at each period end, are considered to be ordinary share equivalents, 
but were not included in the computation of diluted net loss per ordinary share because to do so would have been anti-dilutive: 
Year Ended December 31,
2024
2023
2022
Share options
8,512,314
7,649,008
2,773,633
Unvested restricted share units
15,000
20,000
25,000
Total
8,527,314
7,669,008
2,798,633
Segment Information 
The Company operates in one reportable segment, which comprises the discovery and development of innovative therapeutics. The 
Company's chief operating decision maker ("CODM") is Bill Lundberg, CEO. The CODM measures the performance of the segment 
based on expenses by segment and earnings from operations. The CODM uses these results, in part, to evaluate the performance of, 
and to allocate resources to the segment.
The Company does not consider the impact of certain non-cash operating expenses such as share-based compensation expense, 
amortization of intangible assets, and depreciation of property, plant, and equipment when evaluating the segment. Total assets by 
segment are not presented as that information is not used to allocate resources or assess performance at the segment level and is not 
reviewed by the CODM.
The reconciliation of segment operating results to Consolidated Statement of Operations and Comprehensive Loss for the twelve 
months ended December 31, 2024, 2023, and 2022 is as follows:

F-15
For the twelve months ended December 31,
2024
(in thousands)
Segment
Reconciling 
Items
Consolidated Statement of Operations and 
Comprehensive Loss
Collaboration Revenue
$
36,133
$
-
$
36,133
Less
Research and development Expenses
Petosemtamab - MCLA-158
104,406
-
104,406
Zenocutuzumab - MCLA-128
32,831
-
32,831
MCLA - 129
15,751
-
15,751
Research general
10,079
-
10,079
R&D Employee-Related Expenses - Unallocated
22,664
22,709
(1)
45,373
Other Indirect R&D Expenses - Unallocated
15,824
1,104
(2)
16,928
Total Research and development expenses
201,555
23,813
225,368
General and Administrative expenses
G&A Expenses
38,463
1,357
(2)
39,820
G&A Employee-Related Expenses
19,887
23,125
(1)
43,012
Total General and administrative expenses
58,350
24,482
82,832
Operating loss
(223,772)
(48,295)
(272,067)
Interest Income (Expense)
30,789
-
30,789
Foreign Exchange (losses) gains, net
34,103
-
34,103
Loss before income tax expense
$
(158,880)
$
(48,295)
$
(207,175)
For the twelve months ended December 31,
2023
(in thousands)
Segment
Reconciling 
Items
Consolidated Statement of Operations 
and Comprehensive Loss
Collaboration Revenue
$
43,947
$
-
$
43,947
Less
Research and development Expenses
Petosemtamab - MCLA-158
31,795
-
31,795
Zenocutuzumab - MCLA-128
28,807
-
28,807
MCLA - 129
18,109
-
18,109
Research general
15,935
-
15,935
R&D Employee-Related Expenses - Unallocated
21,983
11,593
(1)
33,576
Other Indirect R&D Expenses - Unallocated
11,282
1,154
(2)
12,436
Total Research and development expenses
127,911
12,747
140,658
General and Administrative expenses
G&A Expenses
27,951
1,431
(2)
29,382
G&A Employee-Related Expenses
15,821
14,633
(1)
30,454
Total General and administrative expenses
43,772
16,064
59,836
Operating loss
(127,736)
(28,811)
(156,547)
Interest Income (Expense)
14,510
-
14,510
Foreign Exchange (losses) gains, net
(9,710)
-
(9,710)
Loss before income tax expense
$
(122,936)
$
(28,811)
$
(151,747)

F-16
For the twelve months ended December 31,
2022
(in thousands)
Segment
Reconciling 
Items
Consolidated Statement of Operations 
and Comprehensive Loss
Collaboration Revenue
$
41,586
$
-
$
41,586
Less
Research and development Expenses
Petosemtamab - MCLA-158
23,145
-
23,145
Zenocutuzumab - MCLA-128
56,419
-
56,419
MCLA - 129
12,321
-
12,321
Research general
19,052
-
19,052
R&D Employee-Related Expenses - Unallocated
16,447
10,658
(1)
27,105
Other Indirect R&D Expenses - Unallocated
10,251
1,131
(2)
11,382
Total Research and development expenses
137,635
11,789
149,424
General and Administrative expenses
G&A Expenses
23,616
223
(2)
23,839
G&A Employee-Related Expenses
14,484
13,877
(1)
28,361
Total General and administrative expenses
38,100
14,100
52,200
Operating loss
(134,149)
(25,889)
(160,038)
Interest Income (Expense)
2,722
-
2,722
Foreign Exchange (losses) gains, net
26,022
-
26,022
Other (losses) gains, net
1,059
-
1,059
Loss before income tax expense
$
(104,346)
$
(25,889)
$
(130,235)
(1) Reconciling item for non-cash share-based compensation operating expense
(2) Reconciling item for non-cash depreciation and amortization operating expense
Recently Adopted Accounting Pronouncements 
From time to time, new accounting pronouncements are issued by the FASB or other standard-setting bodies that are adopted by the 
Company as of the specified effective date. Unless otherwise discussed, the Company believes that the impact of recently issued 
standards that are not yet effective will not have a material impact on its financial position or results of operations upon adoption.
In November 2023, the FASB issued ASU 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment 
Disclosures, which expands annual and interim disclosure requirements for reportable segments, primarily through enhanced 
disclosures about significant segment expenses. ASU 2023-07 is effective for annual periods beginning December 15, 2023, and for 
interim periods beginning after December 15, 2024, with early adoption permitted. The ASU is effective for the Company for the 
annual period ending December 31, 2024. The Company adopted and applied the amendments of this ASU to its disclosures. 
The Company reviewed the other accounting standards that became effective for the annual period ending December 31, 2024, noting 
they do not have a material impact on its financial position or results of operations upon adoption. 
3. Investments in Debt Securities
Debt securities are classified in the consolidated balance sheet as follows:
December 31,
2024
2023
Balance
Balance
(in thousands)
Cash equivalents
$
13,563
$
24,273
Current marketable securities
243,733
150,130
Non-current marketable securities
187,008
57,312
Total
$
444,304
$
231,715

F-17
The following table summarizes debt securities by maturity at December 31, 2024 (in thousands):
Maturity
Amortized Cost
(in thousands)
Within one year
$
257,296
After one year through five years
187,008
Total
$
444,304
The following table summarizes debt securities by credit-quality indicator:
 
Credit Quality Indicator as of December 31, 2024
AAA
AA- to AA+
A- to A+
Total
(in thousands)
Money market funds
$
13,563
$
—
$
—
$
13,563
Corporate paper and notes
—
84,134
201,806
285,940
U.S. government agency securities
991
81,338
5,141
87,470
U.S. treasuries
—
57,331
—
57,331
Total
$
14,554
$
222,803
$
206,947
$
444,304
The credit quality indicator was derived from publicly available ratings published by Moody’s or a comparable credit rating agency, 
last updated as of December 31, 2024. 
The following table summarizes the fair value of debt securities by major security type held at December 31, 2024 (in thousands): 
Description
Amortized 
Cost
Unrealized
Gains
Unrealized
Losses
Fair Value
(in thousands)
Money market funds
$
13,563
$
—
$
—
$
13,563
Corporate paper and notes
285,940
286
(743)
285,483
U.S. government agency securities
87,470
40
(107)
87,403
U.S. treasuries
57,331
14
(187)
57,158
Total
$
444,304
$
340
$
(1,037) $
443,607
The following table summarizes the fair value of debt securities by major security type held at December 31, 2023 (in thousands):
Description
Amortized 
Cost
Unrealized
Gains
Unrealized
Losses
Fair Value
(in thousands)
Money market funds
$
24,273
$
—
$
—
$
24,273
Corporate paper and notes
146,415
425
(148)
146,692
U.S. government agency securities
39,456
24
(70)
39,410
U.S. treasuries
21,571
18
(19)
21,570
Total
$
231,715
$
467
$
(237) $
231,945
The allowance for credit losses applicable to debt securities was immaterial in all periods presented.
Fair Value
The fair value of money market funds is determined based on publicly available market price for these funds (Level 1). The fair value 
of other debt securities is determined based on the publicly available inputs which includes a market price for the same or similar 
instruments adjusted for estimates in interest yield (Level 2).

F-18
4. Prepaid Expenses and Other Assets 
Prepaid expenses and other current assets consisted of the following: 
December 31,
2024
2023
(in thousands)
Prepaid research and development expenses
$
22,794
$
6,872
Prepaid general and administrative costs
2,824
2,058
Interest receivable
3,449
1,552
Other
1,717
1,527
Total
$
30,784
$
12,009
Restricted cash included in other assets totaled $0.7 million and $0.8 million as of December 31, 2024 and 2023, respectively. The 
nature of the restriction relates to amounts held as bank guarantees and collateral for a credit card borrowing arrangement.
5. Property and Equipment, net 
Property and equipment, net consists of the following: 
December 31,
2024
2023
(in thousands)
Laboratory equipment
$
8,497
$
7,489
Office equipment and furniture
1,944
2,052
Leasehold improvements
9,818
10,293
Construction in progress
—
44
Property and equipment
20,259
19,878
Less: accumulated depreciation and amortization
(9,489)
(7,743)
Property and equipment, net
$
10,770
$
12,135
Construction in progress relates to certain ongoing development and construction costs related to the office lease the Company entered 
into with Kadans Science Partner XII B.V. that was entered into during 2022. Additional details for the lease agreement are described 
in Note 9 Operating Leases. Depreciation expense was $2.3 million, $2.3 million and $1.0 million for the years ended December 31, 
2024, 2023 and 2022, respectively. Property and equipment are predominantly located in the Netherlands. 
6. Intangible assets, net 
Intangible assets, net consists of the following:
December 31,
2024
2023
(in thousands)
Licenses of intellectual property
$
3,351
$
3,565
Software licenses
328
184
Intangible assets
3,679
3,749
Less: accumulated amortization
(2,000)
(1,949)
Intangible assets, net
$
1,679
$
1,800
Amortization expense was $0.2 million, $0.2 million, and $0.3 million for the years ended December 31, 2024, 2023 and 2022, 
respectively. Intangible assets are predominantly owned by the Netherlands entity.
Amortization expense over the next five years is expected to be as follows (in thousands):
Year
Expected
amortization
(in thousands)
2025
$
172
2026
172
2027
172
2028
172
2029
156
Thereafter
835
Total remaining value
$
1,679

F-19
7. Accrued Expenses and Other Liabilities
Accrued expenses consisted of the following: 
December 31,
2024
2023
(in thousands)
Accrued research and development expenses
$
30,484
$
27,970
Accrued personnel costs
10,514
8,348
Accrued general and administrative expenses
2,856
2,129
Other
103
35
Accrued expenses
$
43,957
$
38,482
8. Income Taxes 
The components of loss from operations before income tax expense are as follows:
Year ended December 31,
2024
2023
2022
(in thousands)
United States
$
(1,437) $
(6,117) $
(10,437)
Netherlands
(205,738)
(145,630)
(119,798)
Total loss before income taxes
$ (207,175) $ (151,747) $ (130,235)
The components of income tax expense (benefit) from continuing operations are as follows:
December 31,
2024
2023
2022
(in thousands)
U.S. federal
$
6,336
$
1,640
$
1,815
U.S. state
2,136
710
768
Total current tax expense
$
8,472
$
2,350
$
2,583
U.S. federal
$
(227) $
595
$
(1,148)
U.S. state
(94)
247
(476)
Total deferred tax expense (benefit)
$
(321) $
842
$
(1,624)
Total income tax expense
$
8,151
$
3,192
$
959
The Company recognizes income tax expense (benefit) based on its continuing operations in the U.S. The parent company in the 
Netherlands has net operating losses.
The parent company is subject to income tax in the Netherlands where a greater proportion of economic activity is attributed. A 
reconciliation of the Netherlands statutory income tax rate to the Company’s effective income tax rate is as follows: 
Year Ended December 31,
2024
2023
2022
Netherlands statutory income tax rate
25.8%
25.8%
25.8%
Changes in tax rates
—
—
—
Non-deductible expenses
(3.1)
(2.4)
(4.4)
Change in valuation allowance
(26.5)
(24.9)
(22.0)
Other
(0.1)
(0.6)
(0.1)
Effective income tax rate
(3.9)%
(2.1)%
(0.7)%

F-20
In 2020 and 2021, Dutch tax authorities enacted new tax rates applicable to future periods which impact the measurement of deferred 
income taxes. The effect of the change in the valuation allowance each year reflects the increase or decrease in the valuation 
allowance against deferred tax assets attributable to the Netherlands.
The components of the Company’s deferred tax assets (liabilities) consist of the following: 
December 31,
2024
2023
(in thousands)
Deferred tax assets:
Net operating loss carryforwards
$
197,347
$
161,966
Deferred revenue
17,909
10,903
Excess interest carryforward
—
84
Lease obligation
2,570
3,160
Accrued expenses and other
1,550
1,238
Total deferred tax assets
219,376
177,351
Deferred tax asset valuation allowance
(215,419)
(173,152)
Total deferred tax assets, net of valuation allowance
$
3,957
$
4,199
Deferred tax liabilities:
Operating lease right-of-use assets
$
2,400
$
2,953
Other
37
47
Total deferred tax liabilities
$
2,437
$
3,000
Net deferred tax asset
$
1,520
$
1,199
After consideration of all positive and negative evidence, the Company believes that it is more-likely-than-not that our Netherlands 
deferred tax assets that are not supported by reversing temporary differences will not be realized. As a result, the Company established 
a valuation allowance of $215.4 million and $173.2 million as of December 31, 2024 and 2023, respectively. The increase in the 
valuation allowance of $42.3 million and $43.3 million for the years ended December 31, 2024 and 2023, respectively, is primarily 
attributable to the increase in net operating loss carryforward deferred tax assets for which a full valuation allowance applies. As of 
December 31, 2024, the portion of the valuation allowance for deferred tax assets for which subsequently recognized tax benefits 
would be credited directly to contributed capital totaled $11.4 million.
As of December 31, 2024, the Company did not have any net operating losses for U.S. federal or state income tax purposes. The 
Company had net operating loss carryforwards for Dutch income tax purposes of $764.9 million as of December 31, 2024. Under 
Dutch tax law, net operating loss carryforwards may be used to offset future taxable income in full up to €1.0 million and 50% of 
taxable income that exceeds €1.0 million. Effective as of January 1, 2022, these losses can be carried forward indefinitely.
As of December 31, 2024, the Company had no unrecognized tax benefits. As of December 31, 2024, the Company had no accrued 
interest or penalties related to underpayments of income taxes and no amounts have been recognized in the consolidated statements of 
operations. The Company will recognize interest and penalties related to an underpayment of income taxes in income tax expense.
The Company files income tax returns in the U.S. federal and Massachusetts jurisdictions as well as in the Netherlands. The statute of 
limitations for assessment by the Internal Revenue Service (IRS), and Massachusetts tax authorities is closed for tax years prior to 
2021. The statute of limitations for assessment by the Netherlands tax authorities is closed for tax years prior to 2019. The Company is 
not currently under examination by the IRS or any other jurisdictions for any tax years.
9. Operating Leases 
The Company has noncancelable operating leases for offices and lab spaces expiring at various dates through 2032. 
Merus N.V. has non-cancellable operating leases for its corporate headquarters in Utrecht, the Netherlands. In December 2022, the 
Company moved into its new headquarters called the "Accelerator" in the Utrecht Science Park, at 17 Uppsalalaan, 3rd and 4th floor, 
3583 CT, Utrecht. 
On July 19, 2019, Merus N.V. entered into a lease agreement with Kadans Science Partner XIII B.V. (“Kadans”) for the Accelerator 
headquarters. In April 2022, the Accelerator lease between the Company and Kadans commenced. In accordance with the accounting 
requirements under ASC 842, the right-of-use asset and lease obligation were not recorded until the lease commenced. In December 
2022, the Company completed the fit-out construction on approximately 4,957 square meters of office and laboratory space in the 

F-21
premises. The lease provides for a base rent of approximately €1.4 million per annum. The rent amount is subject to adjustment based 
on the consumer price index (the “CPI”) annually, beginning one year after the lease commencement date, subject to certain 
limitations if the CPI is greater than 3.0%. The initial term of the lease is ten years with two 5-year renewal options following the 
initial term, unless earlier terminated by the Company or Kadans, except that the earliest Kadans may terminate the lease is 20 years 
from the completion date of the premise construction. The Company expects the lease to end as of April 4, 2032. On April 5, 2022, the 
Company recognized a right-of-use asset of $11.5 million, or €10.5 million, and a lease liability of $12.4 million, or €11.3 million, on 
the consolidated balance sheets. In connection with signing the lease, the Company received a lease incentive of $0.9 million, or €0.8 
million. To measure the lease liability at the commencement date, the Company discounted the outstanding lease payments using an 
incremental borrowing rate of 4.85%. On April 5, 2024, in accordance with the terms of the lease agreement, the annual rent for the 
Accelerator lease increased due to increases in the consumer price index (CPI). The portion of the rent payments related to the CPI 
index are included within variable lease costs. There have been no other changes in the Company’s lease arrangements during the 
twelve months ended December 31, 2024.
In March 2019, Merus US, Inc. entered into a non-cancellable operating lease agreement for office space in Cambridge, 
Massachusetts. The lease commenced in the second quarter of 2019 and has a term of seven years, and may be extended for another 
five years. Given the Company’s current plans, the renewal term has not been included in the estimate of the lease term. Fixed lease 
payments increase annually and include an increase on an inflationary measure. Variable payments include amounts due to the lessor 
for additional services and cost reimbursements.
The components of lease cost recorded in the Company’s consolidated statement of operations and statement of cash flows were as 
follows: 
For the Year
Ended December 31,
2024
2023
(in thousands)
Operating lease cost
$
2,080 $
2,256
Variable lease cost
235
190
Total lease cost included in operating expenses
$
2,315 $
2,446
Cash paid to lessors included in operating cash 
outflows
$
2,176 $
2,367
The Company’s non-lease cost and other costs paid to the lessor are primarily related to services provided by the lessor in operating 
the premises that includes fees, operating costs, taxes and insurance related to the leased premises. 
Maturities of the Company’s operating lease obligations as of December 31, 2024 were as follows (in thousands): 
Year
Operating
Leases
(in thousands)
2025
$
2,131
2026
$
1,692
2027
$
1,469
2028
$
1,469
2029
$
1,469
Thereafter
$
3,326
Total lease payments
$
11,556
Less: amount representing interest
$
(1,644)
Total lease obligations
$
9,912
The weighted-average remaining lease terms and discount rates related to the Company’s leases were as follows: 
As of December 31,
2024
2023
Weighted-average remaining operating lease term (in 
years)
6.6
7.6
Weighted-average discount rate for operating leases
4.8%
4.8%
10. Commitments and Contingencies 
Indemnities

F-22
The Company indemnifies its officers and directors for certain events or occurrences while the officer or director is, or was, serving at 
the Company’s request in such capacity. The maximum potential amount of future payments the Company could be required to make 
is unlimited; however, the Company has directors’ and officers’ insurance coverage that is intended to limit its exposure and enable it 
to recover a portion of any future amounts paid. 
The Company enters into certain agreements with other parties in the ordinary course of business that contain indemnification 
provisions. These typically include agreements with directors and officers, business partners, contractors, landlords, clinical sites and 
customers. Under these provisions, the Company may indemnify and hold harmless the indemnified party for losses suffered or 
incurred by the indemnified party as a result of the Company’s activities, such as gross negligence, willful misconduct or at times, 
other activities. These indemnification provisions may survive termination of the underlying agreements. The maximum potential 
amount of future payments the Company could be required to make under these indemnification provisions may be unlimited. 
However, to date the Company has not incurred material costs to defend lawsuits or settle claims related to these indemnification 
provisions. As a result, the estimated fair value of these obligations is minimal. Accordingly, the Company did not have any liabilities 
recorded for these obligations as of December 31, 2024.
Litigation 
From time to time, the Company may be involved in various claims and legal proceedings relating to or arising out of the Company’s 
operations. The Company is not currently a party to any material legal proceedings.
On August 5, 2024, the Company filed a complaint in the United States District Court of Delaware against Xencor, Inc. ("Xencor") 
alleging Xencor is infringing the Company's U.S. Patent Numbers (Nos.) 9,944,965 and 9,358,268, and 11,926,859, related to 
Xencor's manufacture, use, offer for sale, sale, and/or importation of certain antibodies and antibody technologies and methods in 
and/or into the United States. The Company is the plaintiff and Xencor is the defendant. As a result of Xencor’s acts, the Company has 
alleged that the Company has suffered and continues to suffer damages, is entitled to recover from Xencor damages sustained as a 
result of Xencor's wrongful and infringing acts, and the Company has and will continue to suffer, irreparable harm for which there is 
no remedy at law. Accordingly, the Company seeks, among other things, damages, equitable remedies, and an award of attorneys' 
fees. On October 10, 2024, Xencor filed a motion to dismiss under Federal Rule of Civil Procedure 12(b)(6), which Merus responded 
to via an answering brief in opposition on October 31, 2024, and to which Xencor replied on November 14, 2024, with further 
submissions by the parties and proceedings to follow. 
On February 11, 2025, Xencor filed two petitions for inter partes review before the Patent Technical Appeal Board of U.S. Patent Nos.  
9,358,268 and 11,926,859, challenging such patents as allegedly invalid as anticipated and obvious in view of certain alleged prior art. 
The Company may file a preliminary response to the petition within three months of the date of the petition.  
On August 19, 2022, Kymab Limited ("Kymab"), a subsidiary of Sanofi, filed a notice of opposition against the Company's 
EP3456190 patent (the "'190 patent"), entitled "Antibody Producing Transgenic Murine Animal," in the European Opposition Division 
of the European Patent Office (the "EPO"). The notice asserted, as applicable, the '190 patent is contrary to the provision of Article 
123(2) EPC, Article 75(1) EPC and Article 100(c) EPC, and alleges the '190 patent lacks novelty and/or is obvious contrary to the 
provisions of Articles 54 and/or 56 EPC, and Article 100(a) EPC, and that the specification of the '190 patent does not provide 
sufficient disclosure of the subject matter of the inventions contravening Article 83 EPC and Article 100(b).  On January 17, 2023, the 
Company timely filed a response before the European Opposition Division of the EPO contesting each of these assertions, with further 
oral proceedings scheduled to follow on January 18, 2024. On June 2, 2023, the European Opposition Division issued a non-binding 
preliminary decision. On January 18, 2024, the European Opposition Division held oral proceedings addressing each allegation of 
invalidity raised by Kymab and maintained the '190 patent as granted, and issued a written decision documenting these conclusions on 
February 16, 2024.  In April 2024, Kymab filed a notice of appeal before the Technical Board of Appeals, and Grounds of Appeal on 
June 17, 2024. The Company filed a response to Kymab's notice of appeal on October 18, 2024, with further submissions by the 
parties and proceedings to follow. The Company does not expect significant impact on its assets or liabilities as a result of the 
opposition proceeding.
11. Shareholders’ Equity 
Each share of common share entitles the holder to one vote on all matters submitted to a vote of the Company’s shareholders. 
Common shareholders are entitled to dividends when and if declared by the board of directors. 
Share Issuances        
In May 2021, the Company entered into an Open Market Sale Agreement (the “2021 Sales Agreement”) with Jefferies LLC 
(“Jefferies”) to sell from time to time up to $125.0 million of the Company’s common share through an “at the market” offering 
program under which Jefferies acts as the sales agent. Subject to the terms and conditions of the 2021 Sales Agreement, Jefferies 

F-23
could sell the common share by any method deemed to be an “at-the-market” offering as defined in Rule 415 promulgated under the 
Securities Act of 1933, as amended (the “Securities Act”).
Jefferies was entitled to compensation at a commission rate of up to 3.0% of the gross proceeds of shares sold under the 2021 Sales 
Agreement. In connection with the sale of the common shares on our behalf, Jefferies was deemed to be an “underwriter” within the 
meaning of the Securities Act and the compensation of Jefferies was deemed to be underwriting commissions or discounts. The 
Company agreed to provide indemnification and contribution to Jefferies with respect to certain liabilities, including liabilities under 
the Securities Act or the Securities Exchange Act of 1934, as amended (the "Exchange Act"). 
As of December 31, 2022, the Company, pursuant to the 2021 Sales Agreement, had issued and sold an aggregate of 2,720,846 shares 
of its common share resulting in gross proceeds of $59.5 million, before deducting sales agent fees of $1.7 million. 
During the year ended December 31, 2023, the Company sold 3,272,280 shares of its common share under the 2021 Sales Agreement 
for gross proceeds of approximately $65.5 million and net proceeds of approximately $63.8 million, after deducting sales agent fees. 
Having sold approximately $124.9 million of the $125.0 million available under the 2021 Sales Agreement, on May 22, 2023, the 
Company delivered written notice to Jefferies, effective as of such date, to terminate the 2021 Sales Agreement. The Company was 
not subject to any termination penalties related to the termination of the 2021 Sales Agreement.
On August 9, 2023, the Company entered into an underwriting agreement (the “2023 Underwriting Agreement”) with Jefferies LLC, 
BofA Securities, Inc., Guggenheim Securities, LLC and William Blair & Company, L.L.C., as representatives of the several 
underwriters named therein (collectively, the “2023 Underwriters”), in connection with the issuance and sale by the Company in a 
public offering of 6,818,182 common shares of the Company, nominal value €0.09 per share, at a public offering price of $22.00 per 
share, less underwriting discounts and commissions, pursuant to an effective shelf registration statement on Form S-3 and 
accompanying prospectus (Registration No. 333-255903), which became effective upon filing on May 7, 2021, and a prospectus 
supplement thereunder. Under the terms of the 2023 Underwriting Agreement, the Company also granted the 2023 Underwriters an 
option exercisable for 30 days to purchase up to an additional 1,022,727 common shares at the public offering price, less underwriting 
discounts and commissions. On August 10, 2023, the 2023 Underwriters exercised this option in full. The offering closed on August 
14, 2023, and the Company received net proceeds of $162.2 million, after deducting underwriting discounts and fees. 
In February 2024, the Company entered into an Open Market Sale Agreement (the “2024 Sales Agreement”) with Jefferies LLC to 
sell from time to time up to $300.0 million of the Company’s common shares through an “at-the-market” offering program under 
which Jefferies acts as the sales agent. Subject to the terms and conditions of the 2024 Sales Agreement, Jefferies could sell the 
common shares by any method deemed to be an “at-the-market” offering as defined in Rule 415 promulgated under Securities Act.
Jefferies is entitled to compensation at a commission rate of up to 3.0% of the gross proceeds of any shares sold under the 2024 Sales 
Agreement. In connection with any sale of the common shares on the Company's behalf, Jefferies would be deemed to be an 
“underwriter” within the meaning of the Securities Act and the compensation of Jefferies would be deemed to be underwriting 
commissions or discounts. The Company agreed to provide indemnification and contribution to Jefferies with respect to certain 
liabilities, including liabilities under the Securities Act or the Exchange Act. There have been no sales under the 2024 Sales 
Agreement through December 31, 2024. 
In connection with entering into the Gilead Collaboration Agreement in March 2024, pursuant to the Subscription Agreement, Gilead 
purchased 452,527 common shares of the Company at a price per share of $55.2454 for aggregate gross proceeds to the Company of 
approximately $25.0 million. Gilead agreed not to transfer, sell, or otherwise dispose of the shares for a period of time following the 
purchase of the shares, subject to certain customary exceptions.
On May 29, 2024, the Company entered into an underwriting agreement (the “2024 Underwriting Agreement”) with Jefferies LLC, 
BofA Securities, Inc., Leerink Partners LLC, Guggenheim Securities, LLC and BMO Capital Markets Corp., as representatives of the 
several underwriters named therein (collectively, the “2024 Underwriters”), in connection with the issuance and sale by the Company 
in a public offering of 7,550,000 common shares of the Company, nominal value €0.09 per share, at a public offering price of $53.00 
per share, less underwriting discounts and commissions, pursuant to an effective shelf registration statement on Form S-3 and 
accompanying prospectus (Registration No. 333-277465), which became effective upon filing on February 28, 2024, and a prospectus 
supplement thereunder. Under the terms of the 2024 Underwriting Agreement, the Company also granted the 2024 Underwriters an 
option exercisable for 30 days to purchase up to an additional 1,132,500 common shares at the public offering price, less underwriting 
discounts and commissions. On May 30, 2024, the Underwriters exercised this option in full. The offering closed on May 31, 2024, 
and the Company received net proceeds of $434.9 million, after deducting underwriting discounts and commissions. 

F-24
12. Collaborations 
Gilead
On March 5, 2024, the Company entered into a collaboration, option and license agreement (the “Gilead Collaboration Agreement”) 
and Share Subscription Agreement (the “Subscription Agreement”) with Gilead Sciences, Inc. (“Gilead”). Gilead agreed to pay the 
Company a $56.0 million, non-refundable upfront payment, and purchased 452,527 common shares at a stated price per share of 
$55.2454 for an aggregate purchase price of $25.0 million. Merus is also eligible to receive license option exercise payments, potential 
development and commercialization milestones, tiered royalties on product sales should Gilead successfully commercialize a therapy 
from the collaboration, and an initiation fee should Gilead exercise its right to include a third Program in the collaboration. Under the 
terms of the Gilead Collaboration Agreement, the Company and Gilead agreed to collaborate on the use of Merus’ proprietary 
Triclonics® platform to develop certain trispecific T-cell engaging multi-specific antibody products for the treatment of certain 
indications. The collaboration shall include at least two, but may include up to three, separate preclinical research programs (each, a 
“Program”) for the design and validation of candidates directed to the applicable Program targets selected by Gilead. On a Program-
by-Program basis, the Company has granted Gilead an exclusive option to obtain an exclusive license for such Program. If Gilead 
exercises the license option with respect to a Program, for the first two Programs, Gilead will be responsible for clinical development 
and commercialization of the products arising from such Program. Upon exercise of its option to include the third Program in the 
collaboration, Gilead will pay the Company a non-refundable upfront initiation fee of $28.0 million, and Merus shall have the option 
to share in the worldwide net profit or loss, including development costs and expenses for the third Program only. 
The initial term of the arrangement is the shorter of the completion of all activities under the applicable research plan or forty-eight 
months following the initiation of research plan activities. If, as of the fourth anniversary of the initiation of activities under the 
applicable Program, Merus has not completed the activities under the then current mutually agreed research plans in accordance with 
the timelines set forth therein (other than due to the act or omission of Gilead), the applicable term shall automatically be extended by 
an additional twelve months (for a maximum term of sixty months), unless otherwise extended by mutual agreement of the parties. 
Gilead's obligations under the collaboration to pay milestones and royalties, continues until the longer of an expiration of certain 
royalty bearing patents or fixed period after a first commercial sale. The arrangement may be terminated in its entirety or in relation to 
one or more Programs for any reason at any time upon ninety (90) days prior written notice to Merus. 
At inception of the arrangement, the Company identified two performance obligations for each of the initial two Programs. The first is 
the License and Research single performance obligation comprised of a combined delivery of a nonexclusive license and related 
activities, including research activities associated with the Program and the activities of the joint steering committee. The second is the 
twelve-month extension (material right) for the Program. Merus accounted for the Program-by-Program options to obtain exclusive 
licenses as a marketing offer because the exclusive license provides Gilead with additional clinical development and 
commercialization rights, and the license option exercise fee of $10.0 million on a Program-by-Program basis was estimated to be 
offered at the standalone selling price.  The option to include a third Program was accounted for as a marketing offer because the non-
refundable upfront initiation fee of $28.0 million was estimated to be offered at the standalone selling price.
The transaction price at inception was comprised of fixed consideration of $58.4 million that was derived from the $56.0 million non-
refundable upfront payment and $25.0 million common shares purchase proceeds, net of the fair value of the common shares delivered 
to Gilead of $22.6 million. All other consideration under the arrangement was determined to be variable consideration and fully 
constrained at inception.  
The fixed consideration was allocated equally between the Program #1 and Program #2 License and Research performance 
obligations, respectively. The equal allocation of the fixed consideration was based on the estimated standalone selling price of each 
performance obligation as each was materially the same.  
The Company initially deferred $58.4 million allocated to the performance obligations to be recognized as revenue over time using an 
output method to measure progress towards completing the research activities dictated by each Program’s respective research plan. 
Development milestones, commercialization milestones and royalties are variable consideration, fully constrained, to be included in 
the transaction price for each performance obligation and recognized in future periods in accordance with the Company’s revenue 
recognition policy. The revenue recognized relating to each combined performance obligation is presented in the notes according to 
the source of consideration received (upfront and milestone), reflective of their differing timing of receipt.
As of December 31, 2024, research activities have commenced, but no milestones have been achieved. The Company received the 
$56.0 million upfront payment from Gilead in April 2024. 
Partner Therapeutics
On November 27, 2024, the Company entered into a license agreement (the "Partner Therapeutics License Agreement") with Partner 
Therapeutics, Inc. ("PTx"). Under the terms of the Partner Therapeutics License Agreement, the Company granted to PTx (i) an 

F-25
exclusive, sublicenseable, royalty-bearing license under certain patent rights and know-how to (a) exploit zenocutuzumab for the 
treatment of NRG1+ cancer in the United States and (b) develop, manufacture and commercialize companion diagnostic tests with 
respect to zenocutuzumab for the treatment of NRG1+ cancer in the United States and (ii) a limited, non-exclusive, non-
sublicenseable, royalty-bearing license under certain patent rights and know-how to commercialize zenocutuzumab for the treatment 
of NRG1+ cancer outside of the United States solely in connection with a named patient program until the Company files for any 
regulatory approval for zenocutuzumab in any country outside the United States. The Company retains all rights not granted to PTx. 
PTx granted to the Company an exclusive, fully paid, royalty-free, perpetual and irrevocable license, with the right to grant 
sublicenses, to certain intellectual property of PTx to exploit zenocutuzumab for (1) the treatment of NRG1+ cancer in a country 
outside of the United States and (2) for any other uses of zenocutuzumab in any other territory. If after three years after the launch of 
zenocutuzumab in the United States, PTx does not to achieve certain specified annual net sales targets, the Company and PTx will 
work in good faith to develop a plan to improve net sales. If in the subsequent year PTx does not achieve the specified annual net sales 
target, the Company has the right to terminate the PTx License Agreement, with all rights reverting to Company.
In exchange for the rights granted under the Partner Therapeutics License Agreement, PTx has agreed to pay an upfront, non-
refundable payment, agreed to fund the development, manufacturing and clinical trial expenses for zenocutuzumab and certain 
companion diagnostic products (other than a portion of the expenses associated with securing or maintaining approval from the United 
States Food and Drug Administration) and the Company is eligible to receive up to $130.0 million in commercialization milestone 
payments based on annual net sales of zenocutuzumab. The Company is also eligible to receive tiered royalties based on the level of 
aggregate annual net sales ranging from high single digits to low twenties until the royalty term expires. PTx also has the option to 
purchase existing quantities of zenocutuzumab from the Company at a specified cost-plus rate. 
The initial term of the arrangement is the period from the first commercial sale until the latest of the following to occur: a) the 
expiration of the last-to-expire valid claim covering zenocutuzumab (b) the launch of a biosimilar; or (c) twelve (12) years after the 
date of the first commercial sale of zenocutuzumab. PTx holds termination for convenience rights and must give 9 months’ notice to 
exercise those rights and may only exercise those rights following the second anniversary of the first commercial sale of 
zenocutuzumab. The Company may terminate the Partner Therapeutics License Agreement if PTx fails to achieve a specified annual 
net sales target in the fourth calendar year after first commercial sale. The Company determined that, at the inception of the contract, 
there are enforceable rights and obligations throughout the term of the contract.  The term of the contract is estimated to be 12 years.
The transaction price at inception was comprised of fixed consideration of the immaterial upfront non-refundable payment. The 
upfront non-refundable consideration is not material to the contract or the Company as a whole. 
As of December 31, 2024, no milestones have been achieved, no royalties have been earned, and no sales of existing zenocutuzumab 
have occurred. 
Lilly
On January 18, 2021, Eli Lilly and Company (“Lilly”) agreed to pay the Company a $40.0 million, non-refundable upfront payment, 
and purchased 706,834 common shares at a stated price per share of $28.295, for an aggregate purchase price of $20.0 million. The 
Company and Lilly agreed to collaborate with respect to the discovery and research of bispecific antibodies utilizing the Company’s 
proprietary Biclonics® bispecific technology platform. The collaboration encompasses up to three (3) independent programs directed 
to the generation of T-cell re-directing bispecific antibodies that bind CD3 and a tumor associated antigen target selected by Lilly to 
be the subject of each program. 
The objective of each program is to develop a lead compound that Lilly would be able to continue to develop through clinical trials. 
Lilly agreed to fund the research activities the Company conducts for each program under an agreed research plan and budget. Lilly 
receives an exclusive, worldwide, royalty-bearing, sublicensable license, under certain patent rights and know-how to exploit certain 
compounds and products directed to designated targets in combination with targeting CD3, or directed to such designated target(s) 
alone as a monospecific antibody or monospecific antibody drug conjugate, subject to rights granted by Merus to third parties under 
one or more existing third party agreements. Merus retains all rights not granted to Lilly. Lilly has certain rights to replace selected 
targets, including the right to substitute a target selection after initial selection for a period of time. The Company may be entitled to 
further milestones and royalties in the future dependent on development and commercialization of any resulting product.
The initial term of the arrangement includes a three-year research term for the Company to perform research and development 
activities, subject to two extension terms of six months at Lilly’s discretion. While the arrangement may be terminated in its entirety 
or on a program-by-program basis at will by Lilly, there are no direct costs or penalties to Lilly to terminate the arrangement prior to 
the end of the initial term.
At inception of the arrangement, the Company identified a single performance obligation comprised of a combined delivery of a 
license and related activities, including research activities associated with a product candidate against the first target and the activities 
of the joint steering committee. The Company also identified two other combined performance obligations relating to options 
exercisable by Lilly to select a second and third target to advance a second and third product candidate against the selected targets 
through discovery and research. 

F-26
The transaction price at inception was comprised of fixed consideration of $43.5 million that was derived from the $40.0 million 
upfront payment and $20.0 million share purchase proceeds, net of the fair value of shares of the shares delivered to Lilly of $16.5 
million, and variable consideration associated with the funding of research services for the product candidate against the first target at 
inception. All other consideration under the arrangement was determined to be variable consideration and fully constrained at 
inception.  
The fixed consideration was allocated equally amongst the three performance obligations and the variable consideration associated 
with each target was allocated to the performance obligation of each respective target.  The equal allocation of the fixed consideration 
was based on the estimated standalone selling price of each performance obligation as each was materially the same.
On February 12, 2021, the Company and Lilly completed the initial exchange of fixed consideration and transfer of common shares. 
The Company initially deferred $43.5 million allocated to the performance obligations to be recognized as revenue over time using a 
cost-to-cost measure of progress toward the development of a lead compound for each respective target, anticipated to be recognized 
as revenue within the initial research term, along with research funding. Development milestones, commercialization milestones and 
royalties are variable consideration, fully constrained, to be included in the transaction price for each performance obligation and 
recognized in future periods in accordance with the Company’s revenue recognition policy. The revenue recognized relating to each 
combined performance obligation is presented in the notes according to the source of consideration received (upfront, reimbursement 
revenue, milestone), reflective of their differing timing of receipt.
During the year ended December 31, 2022, Lilly substituted one of the target programs. The program timeline is expected to extend 
beyond the original research term. Under the current research plan, for the program to be completed in collaboration with Merus, Lilly 
would be required to extend the research term to 2025, subject to its discretion. Lilly exercised the first six month extension in October 
2023 for which there was no associated fee. The program timeline is expected to extend beyond this first extension, and such an 
extension into 2025 would result in a fee of $0.5 million. The $0.5 million extension is included in the Lilly cost-to-cost model as of 
December 31, 2023 and December 31, 2022.  
As of December 31, 2024, research activities were on-going and no milestones have been achieved to date.
Incyte
In December 2016, pending regulatory clearance, Incyte Corporation (“Incyte”) agreed to pay the Company a $120.0 million, non-
refundable upfront payment, and purchased 3.2 million common shares at a stated price per share of $25.00, for an aggregate purchase 
price of $80.0 million. In exchange, the Company granted Incyte with a license to certain of its intellectual property and committed to 
collaborate with Incyte to research, discover and develop monospecific or bispecific antibodies utilizing the Company’s proprietary 
bispecific technology platform. The collaboration is managed by a joint steering committee in which both parties are represented and 
is tasked with overseeing the activities which significantly contributes to the collaboration. The collaboration may encompass up to 
nine product candidates that result from the Company’s application of its proprietary Biclonics® technology platform. During the 
course of the initial research term, Merus proposes product candidates to Incyte, which evaluates whether to designate proposed 
product candidates from the Company to make a selection for further research. Proposed product candidates begin at a pre-clinical 
stage of development. Incyte has certain rights to replace product candidates, including the right to substitute a product candidate after 
initial selection. The Company would be entitled to future consideration in the form of cost reimbursements for research services, 
development milestones, commercialization milestones and royalties related to the programs under the arrangement.
At inception of the collaboration, two potential bispecific product candidates were under preliminary evaluation. After further 
research, a lead candidate was ultimately selected for the first product candidate, designated MCLA-145, and the other potential 
product candidate was not pursued. For the designated product candidate (MCLA-145), the Company retained the exclusive right to 
develop and commercialize products and product candidates in the United States, while Incyte obtained the exclusive right to develop 
and commercialize products and product candidates arising from such program outside the United States. For MCLA-145, the parties 
agreed to conduct and share equally the costs of mutually agreed global development activities and to be solely responsible for 
independent development activities in each party’s respective territories. For all other programs under the arrangement to be selected 
by Incyte, Incyte will be responsible for all research, development and commercialization costs. The Company may elect to co-fund 
the development of certain of the other programs in the future, in which case costs and benefits would be shared. The Company has 
not elected to co-fund any programs to date.
At inception of the arrangement, the Company identified a performance obligation comprised of a combined delivery of a license and 
related activities, including the activities of the joint steering committee, to which to allocate consideration. The arrangement also 
allowed for optional future research services to advance selected product candidates through discovery and research. The transaction 
price was comprised of fixed consideration of an upfront payment of $120.0 million and proceeds from the sale of shares of $80.0 
million. All other consideration under the arrangement was determined to be variable consideration and fully constrained at inception. 
$152.6 million of the transaction price was allocated to the license and related activities performance obligation after accounting for 
the purchase of common shares by Incyte.
On January 23, 2017, the Company completed the sale of shares and exchange of the license. The Company initially deferred $152.6 
million of the transaction price allocated to the license and related performance obligation as deferred revenue, to be recognized as 

F-27
revenue over time as the primary benefit of the license to Incyte is access to the Company’s intellectual property covering its 
Biclonics® technology platform for the generation of potential product candidates. Development milestones, commercialization 
milestones and royalties are variable consideration, fully constrained, to be recognized in future periods in accordance with the 
Company’s revenue recognition policy. Cost reimbursements for research services are recognized as they are performed over time as 
these are considered a separate performance obligation.
In January 2022, the Company announced that Incyte elected to opt-out of its ex-U.S. development of MCLA-145, from the parties 
joint collaboration agreement executed in 2017. At inception of the collaboration, for the designated product candidate (MCLA-145), 
the Company retained the exclusive right to develop and commercialize products and product candidates in the United States, while 
Incyte obtained the exclusive right to develop and commercialize products and product candidates arising from such program outside 
the United States. For MCLA-145, the parties conducted and shared equally the costs of mutually agreed global development 
activities. Incyte’s opt-out of ex-U.S. rights to MCLA-145 provides the Company the exclusive right to develop and commercialize 
potential MCLA-145 products globally. Under the collaboration, Incyte continued to support the program for a limited time while ex-
U.S. activities were transitioned to the Company, and Incyte will retain a right to a residual royalty of up to 4% on sales of future 
commercialization of MCLA-145, if approved. The Company has ceased clinical development of MCLA-145, and is seeking a 
collaboration to continue its potential development.
During the year ended December 31, 2024, the Company recognized a $1.0 million milestone from Incyte related to candidate 
nomination. There were no additional development or commercialization milestones recognized during the year ended December 31, 
2024. During the year ended December 31, 2023, the Company recognized a total of $6.0 million in development milestones. During 
the year ended December 31, 2022, the Company recognized a total of $1.0 million in development milestones.
Ono
In April 2014, the Company granted Ono Pharmaceutical Co., Ltd. (“Ono”) an exclusive, worldwide, royalty-bearing license, with the 
right to sublicense, research, test, make, use and market a limited number of bispecific antibody candidates based on the Company’s 
Biclonics® technology platform against two undisclosed targets directed to a particular undisclosed target combination. 
On March 14, 2018, the Company granted Ono an exclusive, worldwide, royalty-bearing license, with the right to sublicense, 
research, test, make, use and market a limited number of bispecific antibody candidates based on the Company’s Biclonics® 
technology platform against two undisclosed targets directed to a particular undisclosed target combination. Ono is responsible for 
identifying lead candidates and conducting further non-clinical and clinical development activities for such licensed bispecific 
antibodies and pharmaceutical products containing such antibodies, including manufacture and process development. Additionally, 
Ono controls and has exclusive rights over the worldwide commercialization of any approved products, including worldwide supply, 
and is solely responsible for all costs and expenses related to commercialization. Ono has also agreed to fund the Company’s research 
and development activities and be responsible for the payment of all costs and expenses for its own research and development 
activities, which are set out in a mutually agreed upon research plan. The Company retains all rights to use and commercialize any 
antibodies that are generated under the collaborative research program, excluding the up to five lead and/or selected antibodies against 
the targets Ono is pursuing, provided that the use and commercialization is not with respect to the particular target combination. Ono 
agreed to pay the Company an upfront, non-refundable payment of €0.7 million. In addition, the Company was entitled to €0.3 million 
intended to compensate the Company for research services already completed upon entering into the agreement, and €0.2 million to be 
paid to the Company over time for full time equivalent funding. The Company is entitled to research and development milestones in 
addition to royalties on future sales. The Company identified performance obligations for: (1) provision of a license for the target 
combination, and (2) research and development services. The Company concluded that Ono would be able to develop and benefit 
from the license, independent of the research and development services. The research and development services are capable of being 
performed by third parties with an appropriate sub-license, and are recognized over time as these services are delivered. Milestone 
payments are fully constrained as variable consideration to be recognized in future periods in accordance with the Company’s revenue 
recognition policy.
During the year ended December 31, 2024 the Company achieved a $2.0 million development milestone from Ono for the filing of an 
Investigational Drug Application, or equivalent, for an asset arising under this agreement. There were no development milestones 
achieved in the year ended December 31, 2023. The Company achieved a €1.0 million (approximately $1.0 million) development 
milestone in the year ended December 31, 2022. 
Betta
On December 10, 2018, the Company granted Betta an exclusive license to develop and commercialize in China MCLA-129, 
proprietary Biclonics® produced by its Biclonics® technology platform. The Company retains all rights outside of China. Betta has 
agreed to retain a contract manufacturing organization with experience in filing IND applications with U.S. regulatory authorities and 
CTAs with European regulatory authorities in order to produce clinical trial materials for the Chinese market and rest of the world. As 
a key strategic component of the collaboration, Betta will be responsible for IND enabling studies and manufacturing of clinical trial 

F-28
materials in China, which the Company intends to use to assist regulatory filing and early stage clinical development in the rest of the 
world.
In addition to a non-refundable upfront payment of $1.0 million, Betta and the Company will share equally the cost of the transfer of 
the manufacturing technology to a contract manufacturing organization. The Company is also eligible to receive an aggregate of $12.0 
million in milestone payments contingent upon Betta achieving certain specified development and commercial goals as well as tiered 
royalty payments of net sales of any products resulting from the collaboration in China. In turn, Betta is also entitled to milestone 
payments based on the Company’s progress.
The Company identified a single combined performance obligation, being the delivery of the MCLA-129 license including activities 
necessary to complete the technology transfer. The Company had no other commitments. The transaction price is comprised of fixed 
consideration of $1.0 million and fully allocated to the single performance obligation which would be fulfilled at a point in time. The 
technology transfer to deliver the license was completed in 2018 and Company recognized the revenue related to this performance 
obligation of $1.0 million as revenue for the year ended December 31, 2018. Development milestone payments allocated to the 
performance obligation are constrained as variable consideration to be recognized in future periods in accordance with the Company’s 
revenue recognition policy.
To date, both the Company and Betta have achieved a development milestone both valued at $2.0 million. The amounts were 
recognized as milestone revenue of $2.0 million and research and development cost of $2.0 million in the Company’s statement of 
operations for the year ended December 31, 2020. No milestones were achieved during the years ended December 31, 2024, 2023, and 
2022, respectively. 
Contract Assets, Liabilities, Revenues and Expenses
The following tables provide amounts by year indicated and by line item included in the Company's accompanying consolidated 
financial statements attributable to transactions arising from its collaboration arrangements. The dollar amounts in the tables below are 
in thousands.
Third Party
(in thousands)
Incyte
Lilly
Gilead
PTx
Other
Total
Contract assets
Accounts receivable
Balance at January 1, 2024
$
—
$
—
$
—
$
—
$
—
$
—
Billings
6,214
2,011
55,999
—
2,211
$
66,435
Cash receipts
(6,214)
(2,011)
(55,999)
—
(2,211) $ (66,435)
Adjustments
—
—
—
—
—
$
—
Foreign exchange
—
—
—
—
—
$
—
Balance at December 31, 2024
$
-
$
-
$
-
$
-
$
-
$
-
Unbilled receivables
Balance at January 1, 2024
$
1,397
$
839
$
—
$
—
$
193
$
2,429
Accrued receivables
5,414
753
56,045
400
2,197
$
64,809
Billings
(6,214)
(1,514)
(56,045)
—
(2,197) $ (65,970)
Adjustments
—
—
—
—
—
$
—
Foreign exchange
—
—
—
—
(7) $
(7)
Balance at December 31, 2024
$
597
$
78
$
-
$
400
$
186
$
1,261
Contract liabilities
Deferred revenue
Balance at January 1, 2024
$
36,325
$
5,934
$
—
$
—
$
—
$
42,259
Addition to Deferred revenue
—
—
58,387
400
—
$
58,787
Revenue recognized in the period
(17,247)
(5,692)
(4,800)
—
—
$ (27,739)
Foreign exchange
(1,480)
(76)
(2,335)
—
—
$
(3,891)
Balance at December 31, 2024
$
17,598
$
166
$
51,252
$
400
$
-
$
69,416
Less: current portion
(16,555)
(166)
(12,813)
(400)
—
(29,934)
Non-current balance at December 31, 2024
$
1,043
$
-
$
38,439
$
-
$
-
$
39,482

F-29
The balance of unbilled receivables predominantly represents reimbursement revenue under the Company’s collaboration 
arrangements earned in the period to be billed and collected in the next period, generally quarterly. 
For the Year Ended December 31, 2024
(in thousands)
Third Party
Incyte
Lilly
Gilead
PTx
Other
Total
Collaboration Revenue
Upfront payments
$
17,247
$
5,692
$
4,800
$
—
$
—
$
27,739
Reimbursement revenue
4,412
775
—
—
—
$
5,187
Milestones
1,000
—
—
—
2,197
$
3,197
Other
—
—
—
—
10
$
10
Total collaboration revenue
22,659
6,467
4,800
—
2,207
36,133
Operating expenses:
Research and development expense
$
—
$
—
$
—
$
—
$
—
$
—
General and administrative expense
—
—
—
—
—
$
—
Total operating expenses from collaborations
—
—
—
—
—
—
Revenue recognized that was included in deferred 
revenue at the beginning of the period
$
17,247
$
5,692
$
4,800
$
—
$
—
$
27,739
For the Year Ended December 31, 2023
(in thousands)
Third Party
Incyte
Lilly
Gilead
PTx
Other
Total
Collaboration Revenue
Upfront payments
$
17,230
$
10,528
$
—
$
—
$
—
$
27,758
Reimbursement revenue
5,814
4,339
—
—
—
$
10,153
Milestones
5,980
—
—
—
—
$
5,980
Other
—
—
—
—
56
$
56
Total collaboration revenue
29,024
14,867
—
—
56
43,947
Operating expenses:
Research and development expense
$
24
$
—
$
—
$
—
$
—
$
24
General and administrative expense
—
—
—
—
—
$
—
Total operating expenses from collaborations
24
—
—
—
—
24
Revenue recognized that was included in deferred 
revenue at the beginning of the period
$
17,230
$
10,528
$
—
$
—
$
—
$
27,758
For the Year Ended December 31, 2022
(in thousands)
Third Party
Incyte
Lilly
Gilead
PTx
Other
Total
Collaboration Revenue
Upfront payments
$
16,776
$
10,281
$
—
$
—
$
222
$
27,279
Reimbursement revenue
8,602
3,634
—
—
—
$
12,236
Milestones
1,000
—
—
—
1,021
$
2,021
Other
—
—
—
—
50
$
50
Total collaboration revenue
26,378
13,915
—
—
1,293
41,586
Operating expenses:
Research and development expense
$
752
$
—
$
—
$
—
$
—
$
752
General and administrative expense
—
—
—
—
—
$
—
Total operating expenses from collaborations
752
—
—
—
—
752
Revenue recognized that was included in deferred 
revenue at the beginning of the period
$
16,776
$
10,048
$
—
$
—
$
222
$
27,046

F-30
13. Employee Benefit Plans 
Share-Based Compensation
2016 Plan
In 2016, the Company established the 2016 Incentive Award Plan (the “2016 Plan”). All incentive award grants since 2016 are being 
made under the 2016 Plan. At the Company’s annual general meeting of shareholders held on May 7, 2024, the shareholders of the 
Company approved an amendment and restatement of the 2016 Plan that extended the term of the 2016 Plan to December 31, 2031 
and extended the annual “evergreen” feature from and including January 1, 2026 to January 1, 2029.
Options granted to employees under the 2016 Plan generally vest in installments over a four-year period from the grant date: 25% vest 
on the first anniversary of the vesting commencement date, and the remaining 75% of the options vest in 36 monthly installments for 
each full month of continuous service provided thereafter. Options expire after 10 years from the date of grant. 
Options granted to non-executive directors consist of initial option grants as well as subsequent annual awards. The initial award of 
options granted vest in installments over a three-year period: 33% of the options vest on the first anniversary of the vesting 
commencement date, and 67% of the options vest in 24 monthly installments thereafter. Each subsequent award vests over a one-year 
period in 12 monthly installments. The Company measures the fair value of an option through the application of an option pricing 
model, as more fully described below.
The RSUs granted to employees under the 2016 Plan vest in installments over a four-year period from the grant date. Each RSU 
represents the right to receive one common share. The fair value of an RSU is determined by reference to the price of the underlying 
common share.
The number of common shares authorized for issuance for future grants under the 2016 Plan as of January 1, 2025 totaled 2,826,050. 
Share-Based Compensation Expense
Share-based compensation expense is classified in the consolidated statements of operations and comprehensive loss as follows: 
Year Ended December 31,
2024
2023
2022
(in thousands)
Research and development
$
22,709
$
11,593
$
10,658
General and administrative
23,125
14,633
13,877
Total
$
45,834
$
26,226
$
24,535
As of December 31, 2024, share-based compensation expense related to unvested shares was $48.1 million. These shares are expected 
to vest and related costs are expected to be recognized over a weighted average remaining vesting period of 1.3 years.
Share Option Valuation
The Company uses the Black-Scholes option-pricing model to measure the fair value of share option awards. Key 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,
2024
2023
2022
Risk-free interest rate
4.4%
3.6%
2.0%
Contractual life of options (years)
10.0
10.0
10.0
Expected term of options (years)
6.2
6.2
6.3
Expected volatility of underlying shares
67.6%
68.3%
75.5%
Expected dividend yield
0.0%
0.0%
0.0%
The risk-free interest rate is based upon the U.S. Treasury yield curve in effect at the time of grant, with a term that approximates the 
expected life of the option. Prior to April 1, 2022, the Company determined the expected volatility using a blended approach 
encompassing its historical experience and the historical volatility of a peer group of comparable publicly traded companies with 
product candidates in similar stages of development to the Company’s product candidates. From April 1, 2022 onward, the expected 
volatility is based on the annualized daily historical volatility of the Company's share price for a time period consistent with the 
expected term of each grant. A simplified method using a weighted-average mid-point between an award’s vesting date and expiry is 
used to estimate the expected life of options in all periods presented as a sufficient history of participant exercise behavior is not 

F-31
readily observable. The Company has applied an expected dividend yield of 0.0% as the Company has not historically declared a 
dividend and does not anticipate declaring a dividend during the expected life of the options. 
Share Option Activity
The following is a summary of share option activity for the year ended December 31, 2024: 
Number of
Options
Weighted
Average
Exercise
Price per
Share
Weighted
Average
Remaining
Contractual
Term
Aggregate
Intrinsic
Value
(years)
(in thousands)
Outstanding at January 1, 2024
7,649,008
$
19.99
Granted
3,293,355
39.85
Exercised
(1,864,843)
19.76
Forfeited or expired
(565,206)
28.34
Outstanding at December 31, 2024
8,512,314
$
27.16
7.5
$
134,016
Exercisable at December 31, 2024
3,853,456
$
20.35
6.2
$
83,825
Year Ended December 31,
2024
2023
Weighted-average fair value of options granted
$
25.80
$
11.70
Contingent Share Option Awards
On February 1, 2024, the Board of Directors approved the grant of share options to purchase an aggregate of 2,446,045 common 
shares, at an exercise price of $36.09 per share, to employees as the annual grant for 2024. These share option grants were approved 
subject to the Company’s shareholders approving an amendment to the Company’s articles of association to increase the authorized 
share capital (the “Shareholder Approval Condition”), provided that such options would be forfeited if the Shareholder Approval 
Condition was not satisfied by January 1, 2025. On May 7, 2024, the shareholders approved the amendment to the Company’s articles 
of association, including the requisite increase in the authorized share capital satisfying the Shareholder Approval Condition. The 
grant-date fair value of these options is based on the Black-Scholes valuation model, using the fair market value of a common share on 
the date the Shareholder Approval Condition was satisfied. Share-based compensation expense for these options was recorded 
beginning in the second quarter of 2024.
RSU Activity
The following is a summary of RSU activity for the year ended December 31, 2024: 
Number of
RSUs
Weighted
Average
Grant-date 
Fair Value
Non-vested at January 1, 2024
20,000
$
21.20
Granted
—
—
Vested
(3,000)
21.20
Forfeited
(2,000)
21.20
Non-vested at December 31, 2024
15,000
$
21.20
Intrinsic Value of Share Options Exercised and Vested RSUs
Year Ended December 31,
(In thousands)
2024
2023
Total fair value of RSUs vested
$
163
$
238
Aggregate intrinsic value of options exercised
57,710
3,937
Post-Employment Benefit Plan 
The Company has established a post-employment benefit plan for employees of the Netherlands that entitles executive officers and 
other staff members to retire at the age of 67 and receive annual payments based upon the average salary earned during the service 
period. The Company has insured the benefit liabilities through purchased non-participating annuities from an insurance company and 
has no other obligation other than to pay the annual insurance premiums to the insurance company. After purchasing the insurance, the 

F-32
Company has no further obligation (legal or constructive) to pay further amounts if the insurance fund has insufficient assets to pay all 
employee benefits relating to current and prior service. Contributions to purchase non-participating annuities are expensed as incurred 
as service costs. Company contributions to the post-employment benefit plan totaled $2.6 million, $2.8 million, and $2.9 million in the 
years ended December 31, 2024, 2023 and 2022, respectively.
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 U.S. 
employees, and allows participants to defer a portion of their annual compensation on a pretax basis. The Company matches 
contributions 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 $0.4 million, $0.2 million, and $0.1 million for the years ended 
December 31, 2024, 2023, and 2022, respectively.
14. Loss per Share 
The two-class method was not applied for the years ended December 31, 2024, 2023 and 2022 due to the net loss recognized in each 
of those periods. 
Basic and diluted loss per share allocable to common shareholders are computed as follows: 
Year Ended December 31,
2024
2023
2022
(in thousands except per share data)
Net loss
$
(215,326) $
(154,939) $
(131,194)
Weighted average shares outstanding
64,220,765
51,605,444
44,919,084
Basic and diluted loss per share allocable to common shareholders
$
(3.35) $
(3.00) $
(2.92)
 
15. Subsequent Events
In January 2025, the Company entered into a research collaboration and license agreement with Biohaven Ltd ("Biohaven") to co-
develop three novel bispecific antibody drug conjugates (ADCs), leveraging Merus’ Biclonics® technology platform, and Biohaven’s 
ADC conjugation and payload platform technologies.
Under the terms of the agreement, Biohaven is responsible for the preclinical ADC generation of three Merus bispecific antibodies 
under mutually agreed research plans. The agreement includes two Merus bispecific programs previously generated using the 
Biclonics® platform, and one program under preclinical research by Merus. Each program is subject to mutual agreement for 
advancement to further development, with the parties then sharing subsequent external development costs and commercialization, if 
advanced. Merus received an upfront payment of $5.0 million in the form of Biohaven shares pursuant to a private placement 
agreement, and is eligible to receive a license fee at ADC candidate nomination of the first program of $5.0 million, with Merus to 
assume the preclinical bispecific antibody generation cost of the third program, and Biohaven to assume the preclinical ADC 
generation cost for each of the three preclinical; programs. Thereafter, upon mutual agreement to advance each program, the parties 
plan to share further development and commercialization costs. The Company is in progressing of assessing the accounting 
implications of the Biohaven collaboration.