Quarterlytics / Healthcare / Biotechnology / ImmunoGen / FY2015 Annual Report

ImmunoGen
Annual Report 2015

IMGN · NASDAQ Healthcare
Claim this profile
Ticker IMGN
Exchange NASDAQ
Sector Healthcare
Industry Biotechnology
Employees 201-500
← All annual reports
FY2015 Annual Report · ImmunoGen
Loading PDF…
5
1
0
2

F O R M   10 - K 
A N N UA L   R E P O R T

Advancing Antibody-Drug 
Conjugate (ADC)  
Therapies to Help Patients 
and Physicians

Pipeline of ImmunoGen wholly owned and partner programs

Antibody-drug conjugates (ADCs) with our technology are designed to use a tumor-targeting antibody to deliver one of 
our highly potent cell-killing agents specifically to tumor cells. In some cases, the antibody of the ADC also has anticancer 
activity. We have a rich pipeline of wholly owned ADC product candidates, with additional compounds using our technology 
in development by our partners.*

Wholly owned programs

Compound

Therapeutic area

Pre-IND

Phase I / Phase II

Phase III / Pivotal

Approved

ImmunoGen

Mirvetuximab 
soravtansine 
(formerly IMGN853)

Coltuximab 
ravtansine

Ovarian cancer, other  
FRα-postive cancers1

DLBCL2

IMGN529

DLBCL

IMGN779

Acute myeloid leukemia

Partner clinical programs

Genentech/Roche

KADCYLA® 
(ado-trastuzumab 
emtansine)

Second-line metastatic 
breast cancer

Gastric, early breast cancer

Non-small cell lung cancer

Sanofi

SAR6509843

Multiple myeloma

SAR566658

Solid tumors

SAR408701

Solid tumors

Biotest

Indatuximab 
ravtansine 
(BT-062)

Multiple myeloma

Breast, bladder cancers

Amgen

AMG 172

Kidney cancer

AMG 595

Glioblastoma

Bayer

Anetumab 
ravtansine 
(BAY 94-9343)

Novartis

Mesothelioma, ovarian cancers

PCA062

p-CAD positive tumors

*Refer to enclosed 10-K for more details, e.g., targets.  1 FRα = folate receptor α.  2 DLBCL = Diffuse Large B-Cell Lymphoma.  3 Naked antibody; all other compounds are ADCs.  

Dear Fellow Shareholders, 

The past year has been a transformational one for 

the Company: we reported notable initial clinical 
findings with our lead product program, mirvetuximab 
soravtansine (IMGN853); strengthened our position in 
B‐cell malignancies; and advanced our first ADC with 
one of our new IGN payload agents toward the clinic.  

A number of our partners have made significant 

progress as well, advancing several promising product 
candidates into clinical testing in recent months and 
preparing to start potential registration testing with 
other compounds in 2016. 

Mirvetuximab Soravtansine – Encouraging Initial 
Findings in a Difficult Cancer 

The first findings with our folate receptor alpha 

(FRα)‐targeting ADC, mirvetuximab soravtansine, 
assessed specifically in the treatment of FRα‐positive 
platinum‐resistant ovarian cancer, attracted 
considerable attention when reported at the American 
Society of Clinical Oncology (ASCO) meeting in May. 
Notably, 53% of the 17 patients evaluable for 

efficacy at that time experienced marked tumor 
shrinkage characterized as objective responses. 
Current single agent treatments for this disease 
typically have response rates around 15‐20%. Other 
folate receptor targeting approaches have 
demonstrated little activity as single agents in 
platinum‐resistant ovarian cancer, underscoring the 
significance of our ADC technology and these early 
results. 

The data presented at ASCO were from the 
first patients enrolled in the Phase 1 expansion cohort 
of patients with platinum‐resistant, FRα‐positive 
ovarian cancer. In August 2015, we completed 
enrolling all 40 patients into this cohort.  

Once we have mature data from this cohort, we 

plan to discuss the findings with the FDA to determine 
if this promising agent might qualify for an accelerated 
registration pathway in ovarian cancer. We also expect 
to report the 40‐patient data at the 2016 ASCO 
meeting. 

We are using the time for these data to mature to 

continue to advance mirvetuximab soravtansine and 
are on track to start two major trials – FORWARD I and 
FORWARD II – in FRα‐positive ovarian cancer by the 
end of 2015. 

The FORWARD I Phase 2 trial will assess 

mirvetuximab soravtansine, used alone, as a therapy 
for FRα‐positive ovarian cancer previously treated 
with several lines of therapy. Demonstration of benefit 
in this setting currently is believed to be the fastest 
route to market for this ADC.  

Stage 1 of FORWARD I will evaluate two 

dimensions – dosing schedule and target expression 
threshold – which could further enhance the 
tolerability and activity of this promising agent and 
thus the likelihood of clinical testing success. Stage 2 
will reflect these learnings plus FDA input from our 
planned meeting and will compare mirvetuximab 
soravtansine against standard single agent therapies 
for later‐stage ovarian cancer.  

FORWARD II will assess mirvetuximab 
soravtansine used in combination with other 
treatments for ovarian cancer, as part of advancing it 
for earlier lines of therapy. 

In addition to ovarian cancer, FRα is highly 
expressed on other types of solid tumors, and we are 
evaluating these for potential clinical assessment. 

We expect mirvetuximab soravtansine to be the 
first product commercialized by ImmunoGen and are 
committed to advancing it as rapidly as possible. 

Clinical Proof of Concept across a Spectrum of Cancer 
Types 

The early findings with mirvetuximab soravtansine 

in ovarian cancer are exciting, but not unique among 
ADCs with ImmunoGen technology.  

Roche’s Kadcyla® was found to provide survival 
benefits for patients with pretreated HER2‐positive 
metastatic breast cancer (EMILIA trial) and activity 
comparable to chemotherapy plus Herceptin® in first‐
line treatment of this cancer (MARIANNE trial).  
In early testing as a single agent, Bayer’s 

anetumab ravtansine ADC achieved notable, sustained 
tumor shrinkage in five of sixteen patients (31%) with 
pretreated mesothelioma; response rates with other 
agents in this setting are around 10‐15%. 

Beyond these findings in challenging solid tumors, 
distinctive findings have been reported with two ADCs 
with our technology in hematologic settings: 
coltuximab ravtansine – now wholly owned by 
ImmunoGen – in diffuse large B‐cell lymphoma 
(DLBCL) and Biotest’s indatuximab ravtansine in 
multiple myeloma. 

This is a wide spectrum of cancers to be impacted 

by the technology of a single company.   

Promising ADCs for DLBCL – IMGN529 and 
Coltuximab Ravtansine 

DLBCL is a type of non‐Hodgkin lymphoma and 

one of the most prevalent B‐cell malignancies. While 
considerable progress has been made in treatments 
for many of these malignancies, there remains a need 

Partner Progress in Multiple Areas 

There are currently nine anticancer compounds in 
the clinic through our partnerships, including Kadcyla. 
Two of these are expected to start advanced clinical 
testing in 2016, with other partner compounds on 
track to start patient dosing in the next few months.  
Partnerships markedly expand the experience 

base with our technology and provide us with an 
important source of funding. For example, in March, 
Takeda licensed certain rights to use our ADC 
technology, including our IGNs, which benefits both 
companies. We received a $20 million upfront 
payment with the potential to earn significant 
milestone payments with Takeda progress and also 
royalties on the sales of any resulting products.  

In Closing 

We have seen dramatic progress over the past 
year and expect this accelerated pace of change to 
continue. We are aggressively advancing our wholly 
owned compounds, bringing important new 
technologies into the clinic, and leveraging 
partnerships to achieve new therapies for patients.   
This progress would not have been possible 
without the contributions from the dedicated people 
at ImmunoGen working to create new therapies for 
patients across a range of cancers. I thank them for 
their tireless effort and also thank you for your 
support. 

Sincerely, 

Daniel M. Junius 
President and CEO 
September 9, 2015 

for new therapies for DLBCL, particularly for patients 
with later‐stage disease.  

ImmunoGen’s two ADCs for B‐cell malignancies – 

CD37‐targeting IMGN529 and CD19‐targeting 
coltuximab ravtansine – have both shown encouraging 
activity as single agents against heavily pre‐treated 
DLBCL. In fact, the Phase 2 results with coltuximab 
ravtansine in this disease were selected for Best of 
ASCO 2014. 

As recurrent DLBCL is typically treated with a 
combination of therapies, we plan to assess each of 
these ADCs in combination with another anticancer 
agent in DLBCL, and then take the better program 
forward to late‐stage testing.   

In preclinical assessments, IMGN529 

demonstrated pronounced anticancer activity in 
combination with rituximab (Rituxan®), and we are 
preparing to initiate clinical testing of this combination 
by the end of 2015. We are currently assessing 
alternative coltuximab ravtansine combinations in 
laboratory models and plan to initiate clinical testing 
in 2016. 

Extending the Types of Cancers Potentially Treatable 
with ADC Therapeutics 

We invest in research to continue to extend the 

types of cancers potentially treatable with well‐
tolerated ADC therapies. These efforts span payload, 
linker, and antibody technologies as well as other key 
areas. 

All ADCs with our technology in the clinic today 
employ payload agents and linkers that we developed 
at least five years ago. We have had many subsequent 
innovations, including our development of a new 
family of payload agents that we call IGNs.  

Most clinical‐stage ADCs – and all those with our 

technology – utilize payload agents that disrupt 
tubulin, an essential component of a dividing cell. A 
number of cancers are sensitive to tubulin‐acting 
agents, but many are not. 

Our DNA‐acting IGNs are far more potent than our 

tubulin‐acting agents and have the potential to 
markedly expand the types of cancers that can be 
effectively treated with ADCs, such as cancers 
insensitive to tubulin‐acting agents and ones with low 
levels of target expression.   

We are advancing our first IGN‐utilizing ADC, 
IMGN779, toward the clinic and expect begin patient 
dosing with this agent in the first half of 2016. 
IMGN779 targets CD33 and is a potential new 
treatment for acute myeloid leukemia and 
myelodysplastic syndrome.   

 
 
 
 
UNITED STATES
SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

Form 10-K

(cid:2) ANNUAL  REPORT  PURSUANT  TO  SECTION  13 OR 15(d)  OF THE

SECURITIES EXCHANGE  ACT  OF 1934

(cid:3)

For the fiscal year ended June 30, 2015
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 0-17999

ImmunoGen, Inc.

Massachusetts
(State or other jurisdiction
of incorporation or organization)

04-2726691
(I.R.S. Employer
Identification No.)

830 Winter Street, Waltham, MA 02451
(Address of principal executive offices, including zip code)

(781) 895-0600
(Registrant’s telephone number, including area code)

Securities  registered pursuant to Section 12(b) of the Act:

Title of Each Class

Name of  Each Exchange on Which Registered

Common Stock, $.01  par value

NASDAQ Global Select Market

Indicate by  check  mark  if  the registrant  is a  well-known seasoned issuer, as defined in Rule 405 of the Securities

Act.  (cid:2)  Yes (cid:3) No

Indicate by  check  mark  if  the registrant  is not  required to file reports pursuant to Section 13 or Section 15(d) of the

Act.  (cid:3) Yes (cid:2) 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. (cid:2) Yes (cid:3)  No

Indicate by  check  mark  whether the registrant has submitted electronically and posted on its corporate Website, if any,

every Interactive Data  File required to be submitted  and posted pursuant to Rule 405 of Regulation S-T (§229.405 of this
chapter)  during  the preceding  12 months  (or  for  such shorter period that the registrant was required to submit and post such
files). (cid:2) Yes (cid:3)  No

Indicate by  check  mark  if  disclosure  of delinquent filers pursuant to Item 405 of Regulation S-K (§229.405 of this chapter)

is  not  contained herein, and will  not be  contained,  to the best of registrant’s knowledge, in definitive proxy or information
statements incorporated by reference  in Part  III  of  this Form 10-K or any amendment to this Form 10-K.  (cid:2)

Indicate by  check  mark  whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer or a
smaller reporting company.  See definitions  of  ‘‘large accelerated filer,’’ ‘‘accelerated filer,’’ and ‘‘smaller reporting company’’ in
Rule  12b-2 of the Exchange Act.  (Check  one):
Large  accelerated  filer (cid:2)

Smaller reporting company  (cid:3)

Accelerated filer (cid:3)

Non-accelerated filer  (cid:3)
(Do not check if a smaller reporting
company)

Indicate by  check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange

Act).  (cid:3)  Yes (cid:2)  No

Aggregate market value,  based upon the closing sale price of the shares as reported by the NASDAQ Global Select

Market,  of voting stock held by  non-affiliates  at December 31, 2014: $526,298,576 (excludes shares held by executive officers and
directors). Exclusion  of shares held by  any  person  should not be construed to indicate that such person possesses the power,
direct or indirect, to direct  or  cause the  direction  of management or policies of the registrant, or that such person is controlled
by or under common control with the registrant. Common Stock outstanding at August 20, 2015: 86,961,537 shares.

Portions of the  definitive Proxy Statement to be delivered to shareholders in connection with the Annual Meeting of

Shareholders  to be held on November  10, 2015  are incorporated by reference into Part III.

DOCUMENTS INCORPORATED BY REFERENCE

ImmunoGen, Inc.

Form 10-K

TABLE OF CONTENTS

Item

1.
1A.
1B.
2.
3.
3.1
4.

5.

6.
7.

7A.
8.
9.

9A.
9B.

10.
11.
12.

13.
14.

15.

Part I
Business . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Risk Factors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Unresolved Staff Comments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Legal Proceedings
Executive Officers of the Registrant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Mine Safety Disclosures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Part II

Market for Registrant’s Common  Equity,  Related Stockholder  Matters and Issuer

Purchases of Equity Securities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Selected Financial Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Management’s Discussion and Analysis of  Financial Condition and Results of

Operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Quantitative and Qualitative Disclosures  About Market Risk . . . . . . . . . . . . . . . . . . .
Financial Statements and Supplementary Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Changes in and Disagreements  with Accountants on Accounting  and Financial

Page
Number

3
29
43
43
43
43
44

45
45

47
62
64

Disclosure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Controls and Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Other Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

117
117
119

Part III
Directors, Executive Officers  and  Corporate Governance . . . . . . . . . . . . . . . . . . . . . .
Executive Compensation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Security Ownership of Certain  Beneficial  Owners and  Management and Related

Stockholder Matters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Certain Relationships and Related Transactions,  and Director Independence . . . . . . . .
Principal Accounting Fees and Services . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Part IV
Exhibits, Financial Statement Schedules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Signatures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

121
122

2

Item 1. Business

In this Annual Report on Form 10-K, ImmunoGen,  Inc. (ImmunoGen, Inc., together with  its

subsidiaries, is referred to in this document as ‘‘we’’, ‘‘us’’, ‘‘ImmunoGen’’, or the  ‘‘Company’’),
incorporates by reference certain information from  parts of other documents filed with  the Securities
and Exchange Commission. The Securities and Exchange  Commission allows us to disclose important
information by referring to it in that manner.  Please  refer to all such  information when reading this
Annual Report on Form 10-K. All information is  as of June 30, 2015  unless otherwise indicated. For  a
description of the risk factors affecting or  applicable to our business, see  ‘‘Risk  Factors,’’  below.

Overview

ImmunoGen is a clinical-stage biotechnology company focused on the development  of targeted

anticancer therapeutics. All of our wholly owned  clinical and  preclinical  product candidates are
antibody-drug conjugates, or ADCs. An  ADC is a  type of medicine  that uses a  monoclonal antibody to
deliver a therapeutic agent to targeted cells.

We  developed our ADC technology to enable the creation of highly effective, well-tolerated
anticancer products. An ADC with our technology comprises an antibody that binds specifically to an
antigen target found on the surface of cancer cells with  one  of  our potent cancer-cell  killing, or
payload, agents attached to the antibody using one of  our engineered linkers. The antibody component
of an ADC serves to attach the ADC  specifically to a cell with its antigen target on  the surface and  the
payload agent serves to kill the cancer cell. We  have tubulin-acting  payload agents,  such as DM1 and
DM4, which are maytansinoids, and,  more recently, we  developed  DNA-alkylating payload agents, such
as DGN462, which we call IGNs. Our  linkers are engineered to keep our cell-killing agents securely
attached to the antibody while traveling  through the  bloodstream and then control its release and
activation once inside a cancer cell. The antibody component of an ADC may serve only as a  targeting
vehicle or it may also have anticancer  activity, depending on the  antigen target and the antibody
selection criteria.

We  develop our own product candidates using our ADC  technology and  we  license to other
companies limited rights to use our ADC  technology with  their antibodies  to  create products. We  now
have three wholly owned, clinical-stage  anticancer compounds—mirvetuximab  soravtansine, or
IMGN853, coltuximab ravtansine, formerly SAR3419,  and IMGN529—and have reported preclinical
data for IMGN779, which we expect  to  be  our next clinical-stage compound. IMGN779 is the first
ADC utilizing our IGN technology. The most advanced  compound with our ADC technology is Roche’s
marketed product, Kadcyla(cid:4) (ado-trastuzumab emtansine). Eight other ADC compounds and one
non-ADC, or ‘‘naked’’ antibody product candidate,  are in  clinical testing through our partnerships. Our
partnership agreements entitle us to earn  milestone  payments with  agreed-upon achievements and,  for
therapies successfully developed and commercialized,  royalties on product  sales. Our current  partners
are: Amgen Inc., Bayer HealthCare (a subgroup of Bayer AG),  Biotest AG,  Eli Lilly and Company,  or
Lilly, Novartis Institutes for BioMedical Research,  Inc., or Novartis, the Roche Group,  Sanofi and
Takeda. We also have a research agreement with  CytomX Therapeutics that allows each  company to
develop probody-drug conjugates against a specified  number of antigen targets using CytomX’s
Probody(cid:5) antibody-masking technology with our payload  agents and engineered linkers.

We  were organized as a Massachusetts corporation in 1981.  Our principal offices are located  at
830 Winter Street, Waltham, Massachusetts (MA) 02451, and  our telephone number is 781-895-0600.
We  maintain a website at www.immunogen.com, where certain information about us is available. Please
note that information contained on the  website is  not a part of this document. Our Annual Reports on
Form 10-K, Quarterly Reports on Form  10-Q,  Current Reports on Form 8-K, and any amendments to
those reports are available free of charge through the ‘‘Investor Information’’ section of our website as
soon as reasonably practicable after those materials have  been electronically  filed with, or furnished to,

3

the Securities and Exchange Commission. We have adopted  a Code of Corporate Conduct that applies
to all our directors, officers and employees  and a  Senior Officer and Financial  Personnel Code of
Ethics that applies to our senior officers  and financial personnel.  Our Code of  Corporate Conduct and
Senior Officer and Financial Personnel  Code  of Ethics are available  free of charge through the
‘‘Investors’’ section of our website.

Pipeline: Wholly Owned and Partner Product Candidates

Listed in the tables below are the disclosed compounds in development through our own  programs

and our collaborations with other companies.  All  of these  compounds  are ADCs with the exception of
isatuximab, which is a therapeutic antibody.  All of these compounds  are in  early clinical testing
(Phase 1 and/or Phase 2) with the exception of Kadcyla,  which is marketed, and IMGN779, which is in
preclinical testing. Additional earlier-stage compounds are in  development by us and several of our
partners. The results in early clinical trials may not be predictive of  results obtained in subsequent
clinical trials and there can be no assurance that  any of our  or our collaborators’ product  candidates
will advance or will demonstrate the level  of safety  and  efficacy necessary to obtain regulatory approval.

Compounds Wholly Owned by ImmunoGen

Compound

Lead Indication

Mirvetuximab soravtansine . Heavily  pretreated ovarian cancer
IMGN529 . . . . . . . . . . . . . Diffuse large B-cell lymphoma
Coltuximab ravtansine . . . . . Diffuse large B-cell lymphoma
IMGN779 . . . . . . . . . . . . . Acute myeloid leukemia

Stage of
Lead Indication*
Folate receptor (cid:2) Disease specific

Target

CD37
CD19
CD33

Phase 1
Disease specific
Preclinical

Collaborative Partner Compounds

Compound

Lead Indication(s)

Target

Partner Lead Indication(s)*

Stage of

Kadcyla . . . . . . . . . . . Previously treated HER2-positive metastatic breast cancer
Indatuximab ravtansine . Multiple myeloma
Isatuximab** . . . . . . . . Multiple myeloma
Anetumumab ravtansine . Mesothelioma, ovarian cancer
AMG  595 . . . . . . . . . . Glioblastoma
AMG  172 . . . . . . . . . . Kidney cancer
SAR566658 . . . . . . . . . CA6-positive solid tumors
SAR408701 . . . . . . . . . CEACAM5-positive solid tumors
LOP628 . . . . . . . . . . . C-Kit-positive cancer
PCA062 . . . . . . . . . . . P-cadherin-positive solid tumors

Roche
HER2
Biotest
CD138
Sanofi
CD38
Mesothelin
Bayer
EGFRvIII Amgen
Amgen
Sanofi
Sanofi
Novartis
p-cadherin Novartis

CD70
CA6
CEACAM5
c-Kit

Marketed
Disease specific
Disease specific
Disease specific
Disease specific
Disease specific
Phase 1
Phase 1
Phase 1
Phase 1

*

Disease specific is defined as in Phase 1 or  non-pivotal Phase 2 clinical testing for the lead indication.

** Non-ADC  therapeutic antibody

Our Wholly Owned Compounds

Mirvetuximab Soravtansine

Our product candidate mirvetuximab soravtansine, or IMGN853, is a folate receptor alpha ((cid:2)), or

FR(cid:2),-targeting ADC that is a potential treatment for ovarian cancer and certain other FR(cid:2)-positive
solid tumors. This ADC comprises a FR(cid:2)-binding antibody with our potent DM4 cell-killing  agent
attached using one of our engineered linkers.

After the recommended Phase 2 dose  of mirvetuximab soravtansine was established in the
dose-finding portion of a Phase 1 trial, an  expansion cohort was opened to  assess the compound as a

4

single-agent treatment for patients with  platinum-resistant ovarian  cancer. We reported the  first  clinical
findings from this ovarian cancer expansion cohort  at the American Society  of Clinical  Oncology, or
ASCO, annual meeting in May 2015. Mirvetuximab  soravtansine  was found to have notable  single-agent
activity in patients with FR(cid:2)-positive platinum-resistant ovarian cancer and was generally well tolerated.
Based on these findings, we are preparing  to start a Phase 2 study in late 2015 that will assess this
ADC as a single-agent treatment for patients with FR(cid:2)-positive heavily pre-treated ovarian cancer. To
expand the opportunity for mirvetuximab  soravtansine, we  are also planning to initiate a Phase 2 trial
assessing the compound used in combination with  other standard therapies for the treatment  of  ovarian
cancer.

We  are also assessing mirvetuximab soravtansine in  the ongoing  Phase 1  trial as a single-agent
treatment for relapsed/refractory FR(cid:2)-positive endometrial cancer, with other FR(cid:2)-positive uses being
assessed preclinically.

Mirvetuximab soravtansine has been  granted orphan drug status for ovarian  cancer by the U.S.

Food and Drug Administration, or FDA; it has also received  this designation  in the EU.

IMGN529 and Coltuximab Ravtansine

IMGN529 and coltuximab ravtansine are potential treatments for diffuse  large B-cell lymphoma, or

DLBCL and other B-cell malignancies.

(cid:129) IMGN529 includes an ImmunoGen  CD37-targeting antibody that,  in preclinical testing,

demonstrated anticancer activity. DM1  is attached  to  it using one of our  engineered linkers. In a
dose-finding Phase 1 clinical trial, initial  evidence of anticancer activity was reported  with
IMGN529, particularly for patients with  relapsed/refractory  DLBCL.

In preclinical models, IMGN529 has demonstrated  synergistic  activity with  the CD20-targeting
antibody  Rituxan(cid:4) (rituximab). We are planning to start clinical testing  of  IMGN529 in
combination with rituximab in patients with DLBCL in  late 2015.

(cid:129) Coltuximab ravtansine, previously called SAR3419, is  a CD19-targeting  ADC that is a  potential
new treatment for DLBCL. In Phase 2  clinical testing this ADC had encouraging  single-agent
activity in the treatment of relapsed/refractory  DLBCL. These  findings  were  reported at  the
annual meeting of ASCO in 2014 and  selected  for  ‘‘Best  of ASCO’’.

We  plan to initiate clinical testing of coltuximab  ravtansine used in a combination regimen or
regimens for DLBCL in 2016.

IMGN779

IMGN779 is a potential new treatment for  acute myeloid leukemia and  myelodysplastic syndrome.
It  comprises an ImmunoGen CD33-targeting  antibody  with one of our new DNA-acting  payload agents,
DGN462, attached using one of our  engineered linkers. We intend to submit an Investigational  New
Drug, or IND, application for it to the  FDA during the latter half of 2015.

Compounds in Development by Our Partners

The most advanced compound with our  ADC technology  is Roche’s marketed product, Kadcyla

(ado-trastuzumab emtansine). Eight earlier-stage ADCs and one therapeutic antibody are in
development through our collaborations.  We have opt-in  rights for co-development and
co-commercialization of indatuximab  ravtansine,  or BT-062,  jointly  with Biotest in  the US.

(cid:129) Kadcyla (ado-trastuzumab emtansine)—Kadcyla is a HER2-targeting ADC that  consists of Roche’s

trastuzumab antibody with our DM1 cell-killing agent attached using one of our engineered
linkers. Kadcyla was granted marketing  approval in  February 2013  by the U.S.  FDA for the

5

treatment of HER2-positive metastatic breast cancer in  patients who previously received
Herceptin(cid:4) (trastuzumab) and a taxane. It also has international approvals for this indication,
including in the EU and Japan. Roche  is developing Kadcyla for  a  number of additional
HER2-positive solid tumors, including stomach cancer, early breast cancer and lung cancer.

As discussed in the Out-licenses and Collaborations  section  below, earlier this year we  entered
into a royalty purchase agreement that monetized our Kadcyla  royalties.

(cid:129) Indatuximab ravtansine, also referred to as BT-062—This CD138-targeting ADC was created by
Biotest under a license from ImmunoGen. We have opt-in  rights for co-development  and
co-commercialization of indatuximab ravtansine  with Biotest in the  U.S.  The  timing of our opt-in
for this ADC is related to certain development events,  which we expect  to  occur in  2016.

Encouraging findings with indatuximab ravtansine in the  treatment of  multiple myeloma have
been reported, both with the agent used  alone  and as  part  of a combination treatment regimen,
and its development for this cancer is ongoing. The target for indatuximab  ravtansine also has
been found to occur on several types  of  solid  tumors,  and in  early 2014  this ADC began clinical
testing for the treatment of triple-negative breast cancer  and metastatic urinary  bladder cancer.

Promising early clinical data has been reported in  both solid tumors and hematological

malignancies with a number of other  compounds  in development by our partners:

(cid:129) Anetumumab ravtansine, also referred to as BAY  94-9343—This mesothelin-targeting ADC was
created by Bayer under a license from  ImmunoGen. BAY 94-9343 is being  assessed for  the
treatment of mesothelioma and of ovarian cancer in early clinical trials.

(cid:129) Isatuximab, also referred to as SAR650984—This product candidate is a CD38-targeting

therapeutic, or ‘‘naked’’, antibody initially created by ImmunoGen and licensed to Sanofi as part
of a broader research collaboration. SAR650984 has  shown promising activity in early clinical
testing when used alone and as part of a combination  regimen to treat patients  with previously
treated multiple myeloma. Sanofi began Phase  2 testing of SAR650984 for multiple  myeloma in
mid-2014.

(cid:129) AMG 595—This EGFRvIII-targeting ADC also was created by Amgen under a license from
ImmunoGen. It is in Phase 1 clinical testing  for  the treatment of patients with glioblastoma.

(cid:129) SAR566658—This CA6-targeting ADC also was initially  created by ImmunoGen and  licensed to

Sanofi as part of a broad research collaboration. It is in Phase 1 clinical testing for  the treatment
of CA6-positive solid tumors, such as  ovarian cancer.

Several compounds in development by our partners have entered clinical testing and  to  our

knowledge have not yet had clinical data reported:

(cid:129) AMG 172—This CD70-targeting ADC was created  by Amgen under  a license from ImmunoGen.
It  is in Phase1 clinical testing for the treatment  of patients with  clear cell renal  cell  carcinoma.

(cid:129) SAR408701—This CEACAM5-targeting ADC was initially created by ImmunoGen and licensed
to Sanofi as part of a broad research collaboration. It entered Phase 1 clinical  testing in  2014.

(cid:129) LOP628 and PCA062—These ADCs were created by Novartis under licenses from ImmunoGen
and entered Phase 1 clinical testing in  2015. LOP628 targets c-Kit-positive cancers  and PCA062
targets p-cadherin-positive cancers.

Earlier stage preclinical compounds are in  development by us and several of our partners including

Amgen, Novartis, Lilly, Sanofi, Takeda and CytomX.

6

Incidence of Relevant Cancers

Cancer remains a leading cause of death worldwide, and is the  second leading cause of death  in
the U.S.  The American Cancer Society,  or  ACS, estimates  that  in 2015  approximately  1.7 million new
cases of cancer will be diagnosed in the  U.S.  and  that approximately 589,000 people will die  from the
disease. The total number of people  living with  cancer significantly exceeds the number of patients
diagnosed with cancer in a given year  as  patients can live with  cancer for  a year or longer. Additionally,
the potential market for anticancer drugs  exceeds the number  of  patients treated as  many types of
cancer typically are treated with multiple compounds at the same time and because patients often
receive a number of drug regimens sequentially.

Below is information about incidence  of cancers  we are  seeking to treat with  our  wholly owned
compounds. In our clinical testing, we  will define treatment subgroups of patients  for the  cancer types
referenced.

Mirvetuximab Soravtansine—Our mirvetuximab soravtansine compound is  a potential treatment for

ovarian cancer and potentially other  cancers that highly express  its  target, FR(cid:2). Based on published
sources, we believe approximately 21,300 new  cases of ovarian cancer will be diagnosed in  the US  in
2015.

IMGN529 and Coltuximab Ravtansine—We are assessing our  IMGN529 compound and our

coltuximab ravtansine compound as potential treatments for  a type of non-Hodgkin  lymphoma, or
NHL, called DLBCL. Based on ACS estimates, we believe approximately 71,850 new cases of NHL will
be diagnosed in the U.S. in 2015. DLBCL is the  most common type of NHL, representing
approximately one out of every three  cases.

IMGN779—Our preclinical IMGN779 compound  is a potential  treatment for  acute myeloid
leukemia, or AML. Based on ACS estimates, we  believe approximately 20,800 new  cases of AML  will
be diagnosed in the U.S. in 2015.

Out-licenses and Collaborations

We  selectively license restricted access to our ADC technology  to  other companies  to  expand  the

utilization of our technology and to provide us with  cash to fund  our own product programs .  These
agreements typically provide the licensee with rights to use  our ADC technology with its  antibodies or
related targeting vehicles to a defined  target to develop products. The licensee is  generally responsible
for the development, clinical testing,  manufacturing,  registration and commercialization of any resulting
product  candidate. As part of these agreements,  we are  generally  entitled to receive upfront fees,
potential milestone payments, royalties on the sales of any resulting  products and research and
development funding based on activities  performed at our collaborative partner’s request. We  are also
compensated for preclinical and clinical materials  that we supply  to  our partners.

We  only receive royalty payments from our  out-licenses  after a product  candidate developed under

the license has been approved for marketing and commercialized.  Additionally, the  largest milestone
payments under our existing collaborations  usually  are on  later-stage events,  such as commencement of
pivotal clinical trials, product approval  and achievement of defined  annual  sales levels. Achievement of
product  approval requires, at a minimum, favorable completion of preclinical  development and
evaluation, assessment of early-stage clinical trials, advancement  into  pivotal Phase II and/or Phase  III
clinical testing, completion of this later-stage  clinical testing with  favorable results, and completion of

7

regulatory submissions and a positive  regulatory decision. Below is a table  setting forth  our active
agreements and current status of the  product candidates being developed  thereunder:

Agreement Type

Effective Date(s)

Development Status(1)

Partner

Roche(2)

Amgen(3)

Sanofi

Sanofi(4)

Biotest

Multiple single-targets

Multiple single-targets

Multiple single-targets

Right-to-test

Single-target

Bayer HealthCare

Single-target

Novartis

Lilly

CytomX(4)

Takeda(4)

Multiple single-targets

Multiple single-targets

Right-to-test

Right-to-test

2000

2000

2003

2006

2006

2008

2010

2011

2014

2015

Marketed

Phase I

Phase II

Research/Preclinical

Phase I

Phase  I

Phase  I

Research/Preclinical

Research/Preclinical

Research/Preclinical

(1) For agreements involving multiple targets, development status denotes the most advanced  program

under the collaboration.

(2) Roche has five single-target licenses.  Pursuant to the license  covering  the target HER2, which was
entered into in 2000, a product candidate, Kadcyla,  has received marketing approval in the US,
Japan and the EU, along with various  other  countries. The remaining four  licenses were taken
between 2005 and 2008 under another agreement established in 2000,  and the  development status
of product candidates under each of  those  licenses is  research/preclinical.

(3) Amgen has four exclusive, single-target licenses,  one of which has been sublicensed by Amgen to

Oxford  BioTherapeutics Ltd.

(4)

Sanofi,  CytomX and Takeda each have the right to take a defined number  of exclusive, single-
target options that provide the right to take  a defined number  of  single-target licenses, on
pre-negotiated terms, to specified targets during the respective  option periods. As of June 30, 2015,
Sanofi has taken an exclusive license  to  a single  target.

Roche

In May 2000, we granted Genentech, now  a unit of Roche,  an exclusive development and

commercialization license to use our maytansinoid  ADC technology with antibodies, such  as
trastuzumab, or other proteins that target HER2. In February 2013, the  U.S. FDA granted  marketing
approval to the HER2-targeting ADC  compound, Kadcyla. Roche received marketing approval  for
Kadcyla in Japan and in the EU in September 2013 and November 2013, respectively. It has  also
received marketing approval in various other countries around the world. We received a $2 million
upfront payment from Roche upon execution  of  the agreement. We are also entitled to receive up to a
total of $44 million in milestone payments,  plus tiered royalties on the commercial  sales  of  Kadcyla or
any other resulting products as described  below.

The royalty term is determined on a country-by-country basis, and is initially 10 years from  the
date  of  first commercial sale of Kadcyla  in  the country. If, on such  10th anniversary, Kadcyla is covered
by a valid claim under any patents controlled  by  us  (excluding  patents jointly owned by us and
Genentech), then royalties remain payable on sales of Kadcyla in that country for an additional 2 years
and no more.

8

The following two territories are used  in our agreement with Genentech  to  determine the  Kadcyla
sales levels for the calculation of the  applicable tiered  royalty  levels: (1) the U.S. and  (2) the rest of  the
world. Royalties on sales of Kadcyla are paid  quarterly based  on net sales in  each  territory in
accordance with a tiered structure calculated separately in  each of the two territories as follows:

(cid:129) 3% of net sales up to $250 million  in the  calendar year;

(cid:129) 3.5% of net sales above $250 million and up to $400 million  in the calendar year;

(cid:129) 4% of net sales above $400 million  and up to $700 million  in the calendar year;  and

(cid:129) 5% of net sales above $700 million  in  the calendar year.

Royalties will be reduced to a flat 2%  of net sales in any country at any  time  during the royalty
term in which Kadcyla is not covered  by  a valid claim under any patents controlled by us (excluding
patents jointly owned by us and Genentech or solely owned by Genentech) in  such country.

The license agreement also provides for  certain adjustments to the royalties payable  to  us  if

Genentech makes certain third party  license  payments in  order to exploit the  ADC technology
components of Kadcyla, although such adjustments would in no event reduce the royalties  payable for
any country below the greater of 50% of  the royalties otherwise  payable with respect to sales of
Kadcyla in such country, or 2% of net sales in  such country. As of the date of this annual report  on
Form 10-K, we are unaware of any facts or circumstances  that would give rise to such  an adjustment.

Roche may terminate this agreement  for convenience at any  time upon 90 days’  prior written
notice to us. The agreement may also be terminated  by  either party for a material breach by the  other,
subject to notice and cure provisions. Unless earlier  terminated, the agreement will  continue in  effect
until the expiration of Roche’s royalty obligations.

In April 2015, Immunity Royalty Holdings, L.P. paid  us  $200 million to purchase  our  right to
receive 100% of the royalty payments on  commercial sales of Kadcyla  arising  under our development
and commercialization license with Genentech, until Immunity Royalty Holdings has  received  aggregate
Kadcyla royalties equal to $235 million  or $260  million,  depending on when  the aggregate Kadcyla
royalties received by Immunity Royalty Holdings reach a  specified milestone. Once the  applicable
threshold is met, if ever, we will thereafter receive 85% and Immunity Royalty Holdings will receive
15% of the Kadcyla royalties for the remaining  royalty term.

In fiscal  year 2014 we received two $5  million  milestone payments in connection with marketing
approval of Kadcyla in Japan and in the  EU. Through June 30,  2015, we  have received  and recognized
a total of $34.0 million in milestone  payments under this agreement. The next potential  milestone we
will be entitled to receive will be a $5  million regulatory  milestone for marketing approval of Kadcyla
for a first extended indication as defined  in  the agreement.

Roche, through its Genentech unit, also  has licenses for the exclusive right  to  use our maytansinoid

ADC technology with antibodies to four  undisclosed  targets,  which were granted  under the terms of a
separate May 2000 right-to-test agreement  with Genentech. For each  of these  licenses  we received a
$1 million license fee and are entitled to receive up to a total  of $38 million in milestone payments  and
also royalties on the sales of any resulting  products.  We  have not received any milestone payments from
these agreements through June 30, 2015. Roche is  responsible for the development, manufacturing, and
marketing of any products resulting from  these licenses.  Roche  no longer has the  right to take
additional licenses  under the right-to-test agreement.

Amgen

Under a now-expired right-to-test agreement, in September  2009, November 2009 and  December
2012, Amgen took three exclusive development and commercialization licenses, for which  we received

9

an exercise fee of $1 million for each  license taken. In May  2013, Amgen  took  one  non-exclusive
development and commercialization license, for  which we received an exercise fee of $500,000. In
October 2013, the non-exclusive license  was amended  and  converted to an exclusive license,  for which
Amgen paid an additional $500,000 fee  to  us.  Amgen has sublicensed its rights under this license to
Oxford  BioTherapeutics Ltd. We are  entitled to receive  up to a total of $34 million in milestone
payments for each exclusive license, plus royalties on  the commercial sales of any resulting products.

In November 2011, the IND applications to the FDA  for two compounds developed under the

2009 development and commercialization licenses became active,  which triggered  two $1 million
milestone payments to us. The next potential milestone we will  be  entitled to receive  under either  of
these two 2009 development and commercialization licenses will  be  a development  milestone for the
first dosing of a patient in a Phase II  clinical trial, which will  result  in a $3  million payment being due.
The next potential milestones we will  be  entitled to receive under the December 2012  and May 2013
development and commercialization licenses will be a $1  million development  milestone for IND
approval.

Amgen may terminate each development and  commercialization license  for  convenience upon
prior notice to us. Each license may also be terminated by either  party for a  material  breach  by  the
other, subject to notice and cure provisions. Unless earlier terminated, each license will continue  in
effect until the expiration of Amgen’s royalty obligations,  which are  determined on  a
product-by-product and country-by-country basis. For each  product and  country, Amgen’s  royalty
obligations commence with the first commercial  sale of that product in that country,  and extend  until
the later of either the expiration of the last-to-expire ImmunoGen patent covering that product in that
country or the expiration for that country of  the minimum royalty  period specified  in each development
and commercialization license.

Sanofi

Collaboration Agreement

In July 2003, we entered into a broad collaboration agreement  with Sanofi  (formerly Aventis) to
discover, develop and commercialize antibody-based  products.  The  collaboration  agreement provides
Sanofi with worldwide development and  commercialization rights to new antibody-based  products
directed to targets  that are included in  the collaboration, including  the exclusive right to use our
maytansinoid ADC technology in the creation of products  directed to these targets.  The  product
candidates (targets) currently in development under the collaboration  include isatuximab (CD38),
SAR566658 (CA6) and SAR408701 (CEACAM5) and one earlier-stage compound that has yet to be
disclosed. We are entitled to receive milestone payments potentially totaling $21.5 million, per target,
plus royalties on the commercial sales  of  any  resulting products.

The agreement may be terminated by either party for  a material breach by the other, subject  to
notice and cure provisions. Unless earlier  terminated,  the agreement will continue in effect until  the
expiration of Sanofi’s royalty obligations, which are determined on a product-by-product and
country-by-country basis. For each product and country, Sanofi’s  royalty obligations commence  upon
first commercial sale of that product in that country, and extend  until  the later  of  either the expiration
of the last-to-expire ImmunoGen patent covering that product  in that country or the  expiration for that
country of the minimum royalty period specified in the  agreement.

The collaboration  agreement also provides us an  option to certain  co-promotion rights  in the U.S.
on a product-by-product basis. The terms  of  the collaboration agreement allow Sanofi to terminate our
co-promotion rights if there is a change  in  control  of ImmunoGen.

Through June 30, 2015, we have received  and recognized a total of  $20.5 million in milestone
payments related to compounds covered  under  this  agreement now and in the  past, including  a total of

10

$12.5 million in milestone payments related to three  product candidates  previously in the collaboration
that have been returned to us along with the rights  to  the respective targets. In  fiscal 2015, Sanofi
initiated a Phase II clinical trial for isatuximab and  a Phase  I  clinical  trial  for SAR408701 which
triggered a $3 million milestone payment  and  a $1 million milestone payment, respectively,  to  us.

The next potential milestone the Company will  be  entitled to receive for  each of  SAR566658 and

SAR408701 will be a development milestone for initiation of  a  Phase IIb clinical  trial  (as  defined  in the
agreement), which will result in each case in a $3  million payment being due. The next potential
milestone the Company will be entitled  to  receive  with respect to isatuximab will be a  development
milestone for initiation of a Phase III  clinical trial, which will result in a  $3 million  payment being due.
The next potential milestone the Company will  be  entitled to receive for  the  unidentified target  will be
a development milestone for commencement of  a Phase I clinical trial,  which will result in  a $1 million
payment being due.

Right-to-Test Agreement

In December 2006, we entered into a right-to-test agreement with Sanofi.  The  agreement provides

Sanofi with the right to (a) test our maytansinoid ADC  technology with  Sanofi’s antibodies to targets
under a right-to-test, or research, license, (b)  take exclusive  options, with  certain restrictions,  to
specified targets for specified option periods and (c)  upon exercise  of those options, take exclusive
licenses to use our maytansinoid ADC technology to develop and  commercialize products directed  to
the specified targets on terms agreed  upon at  the inception of  the  right-to-test  agreement. The
right-to-test agreement had a three-year original  term from the  activation date  that  was  renewed by
Sanofi in August 2011 for its final three-year  term ending August 31, 2014  by  payment of a  $2 million
extension fee. No additional extensions  are included  in this  agreement, although  any outstanding
options will remain in effect for the remainder of their respective  option terms.

For each development and commercialization license taken, we are entitled to receive an exercise

fee of $2 million and up to a total of $30 million in  milestone payments, plus royalties  on the
commercial sales of any resulting products. In  December  2013,  Sanofi took its first exclusive
development and commercialization license under  the right-to-test agreement, for which we received an
exercise fee of $2 million. The next payment we could receive would either be a $2 million
development milestone payment with the  initiation of a  Phase I clinical  trial under  the first
development and commercialization license taken, or a $2 million  exercise fee  for the  execution of a
second  license.

Each  development and commercialization license  may  be  terminated by either  party for  a material

breach by the other, subject to notice and  cure provisions. Unless earlier  terminated, each  license will
continue in effect until the expiration of Sanofi’s royalty obligations, which are  determined on  a
product-by-product and country-by-country basis. For each  product and  country, Sanofi’s  royalty
obligations commence with the first commercial  sale of that product in that country,  and extend  until
the later of either the expiration of the last-to-expire ImmunoGen patent covering that product in that
country or the expiration for that country of  the minimum royalty  period specified  in each development
and commercialization license.

Biotest

In July 2006, we granted Biotest an exclusive  development and  commercialization license to our

maytansinoid ADC technology for use  with antibodies that target CD138. The  product candidate
indatuximab ravtansine is in development  under this agreement. We received a $1  million upfront
payment from Biotest upon execution of  the agreement. We are also entitled to receive up  to  a total of
$35.5 million in milestone payments, plus  royalties on the commercial sales of any resulting  products.
Through June 30, 2015, we have received  and recognized a total of  $500,000 in milestone payments

11

under this agreement. The next potential  milestone  we will be entitled to receive will be a development
milestone for commencement of a Phase IIb clinical trial (as defined in  the agreement), which will
result in a $2 million payment being due.

The agreement also provided us with the right  to  elect,  at  specific stages  during the  clinical
evaluation of any compound created under the agreement,  to  participate  in the  U.S. development and
commercialization of that compound  in  lieu of receiving  the milestone payments not yet earned and
royalties on sales in the U.S. Currently, we can  exercise  this right during an exercise period specified  in
the agreement by notice and payment to Biotest of an agreed upon opt-in fee of $15  million. Upon
exercise of this right, we would share equally with Biotest the associated further costs of product
development and commercialization in  the U.S.  along with  the profit, if any, from product sales in the
U.S. We would also be entitled to receive  royalties, on  a reduced basis, on product sales  outside the
U.S.

Biotest may terminate the agreement  for convenience at any  time prior to  our election  to
participate in the U.S. development and  commercialization of a compound  created under this
agreement upon prior notice to us. The agreement may also be terminated by either  party for  a
material breach by the other, subject  to  notice and cure provisions. Unless earlier terminated, the
agreement will continue in effect until the  expiration of  Biotest’s  royalty obligations, which  are
determined on a product-by-product  and country-by-country basis. For each product and country,
Biotest’s royalty obligations commence upon first commercial sale  of  that  product in  that  country, and
extend until the later of either the expiration of the last-to-expire ImmunoGen  patent  covering that
product  in that country or the expiration for that country of the minimum royalty  period specified in
the agreement.

Bayer HealthCare

In October 2008, we granted Bayer HealthCare an  exclusive  development and  commercialization

license to our maytansinoid ADC technology for use with antibodies  or  other proteins that target
mesothelin. The product candidate anetumumab ravtansine is in development under this agreement.
We  received a $4 million upfront payment upon execution of  the  agreement. We  are also entitled to
receive, for each product developed and marketed by Bayer HealthCare under  this  agreement, up to a
total of $170.5 million in milestone payments, plus royalties on the  commercial sales  of any  resulting
products.

Bayer HealthCare may terminate the agreement for convenience  at  any time upon  prior written
notice to us. The agreement may also be terminated  by  either party for a material breach by the  other,
subject to notice and cure provisions. We may also terminate the agreement upon the occurrence  of
specified events. Unless earlier terminated, the  agreement will  continue in effect until the expiration of
Bayer HealthCare’s royalty obligations,  which  are determined  on a  product-by-product and
country-by-country basis. For each product and country, Bayer  HealthCare’s royalty obligations
commence upon first commercial sale  of that product  in that country, and extend until  the later  of
either the expiration of the last-to-expire  ImmunoGen patent covering  that  product in  that  country  or
the expiration for that country of the  minimum  royalty period specified  in the  agreement.

Through June 30, 2015, we have received  and recognized a total of  $3 million in milestone
payments under this agreement. The next  potential milestone we will be entitled to receive will  be  a
development milestone for commencement of a non-pivotal Phase II clinical trial, which  will  result in a
$4 million payment being due.

Novartis

Novartis had the right to take six exclusive development and commercialization  licenses under a
right-to-test agreement established in October 2010,  and took these licenses prior to the  expiration of

12

the agreement in October 2014. We received a  $45 million  upfront payment  in connection with the
execution of the right-to-test agreement in 2010, and for each development and commercialization
license taken for a specific target, we  received an exercise fee  of  $1 million and  are entitled to receive
up to a total of $199.5 million in milestone payments,  plus royalties  on the commercial  sales of  any
resulting products. The initial three-year term  of the right-to-test agreement was  extended by Novartis
in October 2013 for an additional one-year  period by payment  of  a $5  million fee to us. We  also are
entitled to receive payments for research and development activities performed on  behalf of Novartis.
Novartis is responsible for the manufacturing,  product development and marketing of any products
resulting from this agreement.

In March 2013, we and Novartis amended  the right-to-test agreement so that Novartis could take a

license to develop and commercialize products directed  at  two undisclosed, related targets, one target
licensed on an exclusive basis and the other target initially licensed on  a  non-exclusive basis.  The  target
licensed on a non-exclusive basis may  no  longer be converted to an exclusive target due to the
expiration of the right-to-test agreement.  We received a  $3.5 million fee  in connection with the
execution of the amendment to the agreement. We may be required to credit this  fee  against future
milestone payments if Novartis discontinues the  development of a specified  product under certain
circumstances.

In connection with the amendment, in  March 2013, Novartis took the license referenced above

under the right-to-test agreement, as  amended,  enabling  it to develop and commercialize products
directed at the two targets. The Company  received a $1 million upfront fee  with the execution  of  this
license. Additionally, the execution of  this license provides the  Company the opportunity to receive
milestone payments totaling $199.5 million or  $238 million,  depending on the composition of any
resulting products.

In October 2013 and November 2013, Novartis  took its second and third exclusive licenses to
single targets, and in October 2014, took  three  remaining exclusive licenses, each triggering a $1  million
payment to the Company and the opportunity to receive milestone payments totaling $199.5 million, as
outlined above, plus royalties on the  commercial sales  of any resulting products. In January 2015,
Novartis initiated Phase I, first-in-human  clinical testing  of  its  cKit-targeting  ADC product  candidate,
LOP628, triggering a $5 million development milestone payment to the Company.  In  May 2015,
Novartis initiated Phase I, first-in-human  clinical testing  of  its  P-cadherin-targeting ADC  product
candidate, PCA062, triggering a $5 million development milestone payment to the Company.  The next
payment the Company could receive would  be  either a $7.5 million  development milestone  for
commencement of a Phase II clinical  trial under  either of these two licenses  or a $5  million
development milestone for commencement of a Phase I clinical trial under  any of its other four
licenses. Additionally, the Company is  entitled to receive  royalties on  product sales, if any.

Novartis may terminate any development and commercialization  license  for convenience  upon
prior notice to us. Each license may also be terminated by either  party for a  material  breach  by  the
other, subject to notice and cure provisions. Unless earlier terminated, each development and
commercialization license will continue in  effect until the expiration of  Novartis’  royalty obligations,
which  are determined on a product-by-product  and  country-by-country  basis. For each product  and
country, Novartis’ royalty obligations  commence upon first commercial sale of that product  in that
country, and extend until the later of either the expiration of the last-to-expire ImmunoGen  patent
covering that product in that country  or  the expiration for that country of the  minimum royalty period
specified in each license.

Lilly

Lilly had the right to take three exclusive development and commercialization  licenses under a
right-to-test agreement established in December 2011, and  took these licenses prior to the  expiration of

13

the agreement in December 2014. We  received a  $20 million  upfront payment  in connection with the
execution of the right-to-test agreement in 2011. Under the terms of this right-to-test  agreement, the
first license had no associated exercise fee, and the second  and third licenses each had a $2 million
exercise fee. The first development and  commercialization license was taken in  August 2013  and the
agreement was amended in December 2013 to provide  Lilly with  an extension provision and
retrospectively include a $2 million exercise fee for the  first license  in lieu of the  fee due for either  the
second  or third license. The second and  third  licenses were taken in  December 2014,  with one
including the $2 million exercise fee and  the other not. Under the two licenses with  the $2 million
exercise fee, we are entitled to receive  up  to a  total  of $199 million in milestone payments,  plus
royalties on the commercial sales of any  resulting products. Under the  license taken in December 2014
without the exercise fee, the Company  is entitled to receive  up to a total of $200.5 million in  milestone
payments, plus royalties on the commercial sales of any resulting products.  The  next payment  the
Company could receive would be a $5 million development  milestone payment  with the initiation  of  a
Phase I clinical trial under any of these three development and commercialization  licenses taken. We
also are entitled to receive payments  for  delivery of cytotoxic  agents  to  Lilly and research and
development activities performed on  behalf of Lilly. Lilly is responsible for the manufacturing, product
development and marketing of any products resulting from this collaboration.

Lilly may terminate any development and commercialization license for  convenience upon  prior
notice to us. Each license may also be terminated  by  either party for a material breach by the  other,
subject to notice and cure provisions. We may also terminate the agreement upon the occurrence  of
specified events. Unless earlier terminated, each  development and commercialization license  will
continue in effect until the expiration of Lilly’s royalty obligations, which are determined on a
product-by-product and country-by-country basis. For each  product and  country, Lilly’s  royalty
obligations commence upon first commercial sale of that  product in that country,  and extend until the
later of either the expiration of the last-to-expire  ImmunoGen patent covering that product in that
country or the expiration for that country of  the minimum royalty  period specified  in each license.

CytomX

In January 2014, we entered into a reciprocal right-to-test agreement with CytomX.  The agreement

provides CytomX with the right to test  our  ADC technology with CytomX Probodies to create
Probody-drug conjugates (PDCs) directed  to a  specified  number  of targets under a right-to-test, or
research, license, and to subsequently  take an exclusive, worldwide license to use our ADC  technology
to develop and commercialize PDCs directed to the  specified targets on terms agreed  upon at the
inception of the right-to-test agreement.  We received no upfront cash payment  in connection with the
execution of the right-to-test agreement. Instead, we received reciprocal rights to CytomX’s Probody
technology whereby we were provided  the  right  to  test CytomX’s Probody  technology to create PDCs
directed to a  specified number of targets  and to subsequently take  exclusive, worldwide licenses to
develop and commercialize PDCs directed to the  specified targets on terms agreed  upon at the
inception of the right-to-test agreement.  The terms of the  right-to-test agreement require us and
CytomX to each take its respective development and commercialization licenses by the end  of  the term
of the research license. In addition, both we  and CytomX  are required to perform specific  research
activities under the right-to-test agreement on behalf of  the other party for no  monetary  consideration.

With respect to the development and  commercialization license that may be taken by CytomX, we
are entitled to receive up to a total of  $160 million in milestone payments per license,  plus royalties  on
the commercial sales of any resulting product. Assuming  no annual maintenance  fee is payable  as
described below, the next payment we could receive would be a $1 million development  milestone
payment with commencement of a Phase  I  clinical trial.

With respect to any development and  commercialization license that may be taken  by  us, we will

potentially be required to pay up to  a total of $80  million in milestone payments per license,  plus

14

royalties on the commercial sales of any  resulting product.  Assuming no  annual maintenance  fee  is
payable as described below, the next payment we could be required  to  make is a $1  million
development milestone payment with commencement of a  Phase I clinical trial.

In addition, each party may be liable to pay annual maintenance fees to the other  party if  the

licensed PDC product candidate covered  under each development and commercialization  license has
not progressed to a specified stage of development within  a specified time frame.

Takeda

In March 2015, we entered into a right-to-test agreement with  Takeda Pharmaceutical Company

Limited (Takeda) through its wholly owned subsidiary, Millennium  Pharmaceuticals, Inc. The
agreement provides Takeda with the  right  to  (a) take exclusive options, with  certain  restrictions, to
individual targets selected by Takeda  for specified option  periods, (b) test our ADC technology  with
Takeda’s antibodies directed to the targets optioned under a right-to-test, or research, license, and
(c) take exclusive licenses to use our ADC technology  to  develop  and commercialize products  to  targets
optioned  for up to two individual targets  on  terms specified  in the right-to-test agreement. Takeda  must
exercise its options for the development  and commercialization licenses by the end  of the three-year
term of the right-to-test agreement, after which  any  then outstanding options will lapse. Takeda  has the
right to extend the three-year right-to-test period for one additional year  by  payment to us of
$4 million. Alternatively, Takeda has the  right to expand the scope of the right-to-test  agreement by
payment to us of $8 million. If Takeda opts to expand the  scope  of the right-to-test agreement, it will
be entitled to take additional exclusive  options, one  of  which may be exercised for an additional
development and commercialization license, and the right-to test period will be extended until  the fifth
anniversary of the effective date of the right-to-test  agreement. Takeda is responsible for the
manufacturing, product development and marketing of any products resulting from this collaboration.

We  received a $20 million upfront payment in  connection with the execution of the  right-to-test
agreement and, for each development  and commercialization license taken, are entitled  to  receive up to
a total of $210 million in milestone payments, plus  royalties on  the commercial sales of any resulting
products. The first potential milestone the Company will be entitled to receive  will  be  a $5 million
development milestone payment with the  initiation of a  Phase I clinical  trial under  the first
development and commercialization license taken. We also  are  entitled  to receive payments  for delivery
of cytotoxic agents to Takeda and research and development activities  performed  on behalf  of  Takeda.

Takeda may terminate any development  and commercialization license for convenience  upon prior

notice to us. Each license may also be terminated  by  either party for a material breach by the  other,
subject to notice and cure provisions. Unless earlier  terminated, each development and
commercialization license will continue in  effect until the expiration of  Takeda’s royalty  obligations,
which  are determined on a product-by-product  and  country-by-country  basis. For each product  and
country, Takeda’s royalty obligations  commence upon  first commercial  sale  of  that  product in  that
country, and extend until the later of either the expiration of the last-to-expire ImmunoGen  patent
covering that product in that country  or  the expiration for that country of the  minimum royalty period
specified in each license.

Patents, Trademarks and Trade Secrets

Our intellectual property strategy centers  on obtaining  patent  protection for our proprietary

technologies and product candidates.  As  of  June  30, 2015, our  patent portfolio had a total  of  659 issued
patents worldwide and 645 pending patent applications worldwide. We  seek  to  protect our ADC
technology and our product candidates through a  multi-pronged approach.  In  this regard, we  have
patents and patent applications covering antibodies and other cell-binding agents, linkers, cell-killing
agents (e.g., tubulin-acting maytansinoids and DNA-acting cell-killing agents), and complete ADCs,

15

comprising these components and methods  of making and using each of the above.  Typically,  multiple
issued patents and pending patent applications  cover various aspects  of each product candidate.

We  consider our cell-killing agent technology  to  be  a key component of our overall corporate
strategy. We currently own 50 issued  U.S. patents covering various embodiments of our maytansinoid
technology including claims directed to certain maytansinoids, antibody-maytansinoid conjugates and
other cell-binding agents used with maytansinoids, and methods  of  making and using the same. In  all
cases, we have received or are applying  for comparable patents in  other jurisdictions including Europe
and Japan. We have issued patents that  cover numerous aspects of  the manufacture of both our DM1
and DM4 cell-killing agents. These issued patents remain in  force until  various times between 2020  and
2026. We also have several composition  of matter  patents covering various aspects of our DM4
cell-killing agent and antibody-maytansinoid conjugates  incorporating DM4 that are expected to remain
in force until 2024-2033. We have five  issued  U.S. patents  covering various  aspects of our DNA-acting
cell-killing agents, which will expire at various times between 2029  and 2033. We also  have six
additional pending U.S. patent applications  disclosing and claiming other related embodiments  of this
technology. Patents that may issue from  these applications will, if  issued, expire  between  2030 and 2036.
In all cases, we are also applying for comparable patents in other jurisdictions, including  Europe and
Japan.

Our intellectual property strategy also includes  pursuing patents directed to linkers, antibodies,

conjugation methods, ADC formulations  and  the use of specific antibodies  and ADCs  to  treat certain
diseases.  In this regard, we have issued patents and pending patent applications related  to  many of our
linker technologies. These issued patents, expiring  in 2021-2031, and  any patents which may  issue from
the patent applications, cover antibody-maytansinoid  conjugates using these linkers. We also have issued
U.S. patents and pending patent applications covering methods of assembling ADCs from  their
constituent antibody, linker and cell-killing agent moieties. These issued  patents  will  expire in
2021-2030, while any patents that may issue from pending patent applications also covering various
aspects of these technologies will, if issued,  expire between 2021  and 2034. We also have issued patents
and pending patent applications related to monoclonal antibodies  that may be a component of an  ADC
compound or may be developed as a  therapeutic, or  ‘‘naked,’’ antibody anticancer compound.

We  expect our continued work in each of these areas  will  lead to other patent applications. In all
such cases, we will either be the assignee  or  owner of such patents  or have  an exclusive license  to  the
technology covered by the patents.

The rates at which we are entitled to receive royalties based on  sales of  Kadcyla in  any particular
country depend in part on whether the  manufacture,  use or  sale of Kadcyla is covered by ImmunoGen
patent rights in that country. In this regard, we own  patents in the U.S. and Europe  covering the
composition of matter of Kadcyla that expire at the earliest in  2023 and  2024, respectively, and may be
eligible for extension of those terms under applicable patent laws in those jurisdictions. We also own
patents in the U.S. and Europe that cover  various elements  of the manufacture  of  Kadcyla, with
expiration dates extending to at least  2027 and 2026,  respectively. Notwithstanding  these  patent  terms,
the period during which we are entitled to receive royalties based  on sales of Kadcyla  in any  country
does not extend beyond the 12th anniversary of the date of the first commercial sale of Kadcyla in such
country.

We  cannot provide assurance that the  patent  applications will  issue as  patents  or that any  patents,

if issued, will provide us with adequate  protection  against competitors with respect to the  covered
products, technologies or processes. Defining the  scope  and term  of patent protection  involves complex
legal and  factual analyses and, at any  given  time, the  result of  such analyses may be uncertain. In
addition, other parties may challenge  our patents  in litigation or administrative proceedings resulting  in
a partial or complete loss of certain patent rights  owned or controlled by  ImmunoGen,  Inc.
Furthermore, as a patent does not confer  any  specific freedom to operate, other parties may  have
patents that may block or otherwise hinder  the development and commercialization of our technology.

16

On October 29, 2014, the Patent Trial  and Appeal Board of the United States  Patent and

Trademark Office, or PTAB, instituted an inter partes review, or IPR, of the claims in our U.S. Patent
No. 8,337,856, or the ’856 Patent, that covers Kadcyla.  The PTAB heard oral argument  in this matter
on July 9, 2015, and a ruling by the PTAB  is expected by  the end of October 2015. The  ’856 Patent  is
one of several U.S. patents we hold that  pertain to Kadcyla.  Consequently, any adverse outcome of  the
IPR is not expected to impact either  the royalty  revenue we are entitled to receive  from Roche on
Kadcyla sales in the U.S., or the $200 million royalty  monetization transaction relating to our  Kadcyla
royalty stream that was consummated  in April 2015.

Many of the processes and much of the  know-how that  are important to us depend upon the skills,

knowledge and experience of our key  scientific and technical personnel, which skills, knowledge and
experience are not patentable. To protect our rights  in these areas, we require that all employees,
consultants, advisors and collaborators enter into  confidentiality agreements  with us. Further, we
require that all employees enter into assignment of invention agreements  as a condition of employment.
We  cannot provide assurance, however, that these agreements will provide adequate or any meaningful
protection for our trade secrets, know-how or  other proprietary  information  in the event of  any
unauthorized use or disclosure of such  trade secrets, know-how  or  proprietary information. Further, in
the absence of patent protection, we may  be  exposed to competitors  who independently develop
substantially equivalent technology or otherwise  gain access to our  trade secrets, know-how  or other
proprietary information.

Competition

We  focus on highly competitive areas of product development. Our competitors include  major
pharmaceutical companies and other biotechnology firms.  For example, Pfizer,  Seattle Genetics, Roche
and Bristol-Myers Squibb have programs  to attach  a proprietary  cell-killing small  molecule to an
antibody  for targeted delivery to cancer cells. Pharmaceutical and  biotechnology companies, as well  as
other institutions, also compete with us  for promising targets for  antibody-based therapeutics and in
recruiting highly qualified scientific personnel.  Additionally, there are non-ADC therapies  available
and/or in  development for the cancer  types we and our partners are targeting.  Many competitors  and
potential competitors have substantially greater  scientific, research and product  development
capabilities, as well as greater financial, marketing and human resources than we do.  In addition, many
specialized biotechnology firms have  formed collaborations  with large, established companies  to  support
the research, development and commercialization  of  products  that may  be  competitive with ours.

In particular, competitive factors within the antibody and cancer therapeutic  market  include:

(cid:129) the safety and efficacy of products;

(cid:129) the timing of regulatory approval and commercial  introduction;

(cid:129) special regulatory designation of products,  such as  Orphan Drug designation; and

(cid:129) the effectiveness of marketing, sales, and reimbursement efforts.

Our competitive position depends on our ability to develop effective proprietary products,

implement clinical development programs,  production plans and marketing plans,  including
collaborations with other companies with greater marketing resources than ours, and  to  obtain  patent
protection and secure sufficient capital  resources.

Continuing development of conventional and  targeted chemotherapeutics by large pharmaceutical

companies and biotechnology companies  may result in new compounds that may  compete with our
product  candidates. Antibodies developed by  certain of these companies have been approved for  use as
cancer therapeutics. In the future, new  antibodies or other  targeted  therapies  may compete with  our
product  candidates. Other companies  have created or have programs to create potent cell-killing agents

17

for attachment to antibodies. These companies may compete with  us for technology out-license
arrangements.

Regulatory Matters

Government Regulation and Product Approval

Government authorities in the U.S.,  at  the federal, state and local level, and other  countries
extensively regulate, among other things, the research, development,  testing, manufacture,  quality
control, approval, labeling, packaging,  storage,  record-keeping, promotion, advertising, distribution,
marketing and export and import of  products such as those we are developing. A new drug must be
approved by the FDA through the new drug application, or  NDA, process and  a new  biologic must be
approved by the FDA through the biologics  license application, or BLA, process before  it may  be
legally marketed in the U.S.

U.S. Drug Development Process

In the U.S., the FDA regulates drugs under  the federal  Food, Drug, and  Cosmetic  Act,  or FDCA,

and in the case of biologics, also under the Public  Health Service  Act, or PHSA,  and implementing
regulations. The process of obtaining regulatory approvals and the subsequent compliance with
appropriate federal, state, local, and foreign statutes  and regulations require the expenditure of
substantial time and financial resources.  Failure to comply  with the applicable U.S. requirements at any
time during the product development process, approval process or after  approval, may subject an
applicant to administrative or judicial  sanctions.  These sanctions could  include the FDA’s refusal to
approve pending applications, withdrawal of an approval, a clinical hold, warning letters,  product
recalls, product seizures, total or partial suspension of production or distribution, injunctions, fines,
refusals of government contracts, restitution,  disgorgement, or civil or criminal penalties. Any agency or
judicial enforcement action could have a  material adverse effect on us.  The process required  by  the
FDA before a drug or biologic may be  marketed in  the U.S. generally involves the following:

(cid:129) completion of preclinical laboratory tests,  animal studies and formulation studies  according to

current Good Laboratory Practices (cGLP) or other applicable regulations;

(cid:129) submission to the FDA of an IND which  must become effective before human  clinical trials  may

begin;

(cid:129) performance of adequate and well-controlled  human clinical trials according  to  current Good
Clinical Practices (cGCP) to establish the safety and efficacy  of  the proposed drug  for its
intended use;

(cid:129) submission to the FDA of an NDA  or BLA;

(cid:129) satisfactory completion of an FDA  inspection  of the manufacturing facility or facilities at which

the drug is produced to assess compliance with current  Good Manufacturing  Practice (cGMP) to
assure that the facilities, methods and controls are adequate to preserve  the  drug’s identity,
strength, quality and purity; and

(cid:129) FDA review and approval of the NDA or BLA.

Once a pharmaceutical candidate is identified for development, it enters the  preclinical testing
stage. Preclinical tests include laboratory  evaluations of product chemistry, toxicity  and formulation,  as
well as animal studies. An IND sponsor must submit the  results of the  preclinical tests, together with
manufacturing information and analytical  data, to the  FDA as part of the IND.  The sponsor will also
include a protocol detailing, among other things,  the objectives of the  first  phase of the clinical trial,
the parameters to be used in monitoring safety, and the effectiveness criteria to be evaluated, if the
first phase lends itself to an efficacy evaluation. Some preclinical testing may continue even after the

18

IND is submitted. The IND automatically  becomes effective 30 days  after receipt by the FDA,  unless
the FDA, within the 30-day time period, places the clinical trial on a clinical hold. In such  a case, the
IND sponsor and the FDA must resolve  any  outstanding concerns before the clinical trial can  begin.
Clinical holds also  may be imposed by the FDA  at any time before or during clinical trials due to safety
concerns about on-going or proposed  clinical trials  or non-compliance  with specific FDA requirements,
and the trials may  not begin or continue  until the  FDA notifies the sponsor that the  hold  has been
lifted.

All clinical trials must be conducted  under the supervision of one or more qualified investigators in
accordance with cGCP regulations. They  must be conducted under protocols detailing  the objectives of
the trial, dosing procedures, subject selection and exclusion criteria and the safety and effectiveness
criteria to be evaluated. Each protocol  must be submitted  to  the  FDA as part  of  the IND, and timely
safety reports must be submitted to the FDA  and the  investigators  for serious and unexpected adverse
events. An institutional review board,  or IRB, at each institution  participating in the clinical trial must
review and approve each protocol before  a clinical trial commences at that institution and  must  also
approve the information regarding the trial and the consent form that must  be  provided to each trial
subject or his or her legal representative,  monitor the study until completed  and otherwise comply with
IRB regulations.

Human clinical trials are typically conducted  in three  sequential phases that may overlap or be

combined:

(cid:129) Phase I: The product candidate is initially introduced into healthy  human subjects  and tested for
safety, dosage tolerance, absorption,  metabolism, distribution and excretion. In the  case of some
products for severe or life-threatening diseases, such as cancer, especially  when the product may
be too inherently toxic to ethically administer to healthy  volunteers, the  initial human testing is
often conducted in patients.

(cid:129) Phase II: This phase involves clinical trials 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 and  optimal dosage.

(cid:129) Phase III: Clinical trials are undertaken to further evaluate dosage, clinical  efficacy and safety  in
an expanded patient population at geographically  dispersed clinical study sites. These  clinical
trials are intended to establish the overall risk-benefit  ratio of the  product candidate  and
provide, if appropriate, an adequate  basis for product  labeling.

Post-approval trials, sometimes referred to as  Phase IV, may be conducted after initial  marketing

approval. These trials are used to gain additional experience  from the treatment of patients in the
intended therapeutic indication. In certain  instances, the  FDA may mandate  the performance of
Phase IV clinical trials as a condition of approval of an  NDA or BLA.

The FDA or the sponsor may suspend a clinical trial at any  time  on various grounds, including a

finding that the research subjects or patients are being exposed to an unacceptable health risk.
Similarly, an IRB can suspend or terminate approval of a clinical trial at its institution if  the clinical
trial is not being conducted in accordance with  the IRB’s  requirements or if  the drug has been
associated with unexpected serious harm to patients. Additionally, some clinical  trials are overseen  by
an independent group of qualified experts  organized by the  sponsor,  known as a data safety  monitoring
board or committee. Depending on its charter, this  group may determine whether a trial may  move
forward at designated check points based  on  access to certain  data from the trial. Phase I, Phase  II,
and Phase III testing may not be completed  successfully within any specified period, if  at all.

During  the development of a new drug,  sponsors  are given  opportunities  to meet with the FDA at
certain points. These points may be prior  to  submission  of  an IND,  at the end  of Phase II, and  before
an NDA or BLA is submitted. Meetings  at other times may  be  requested.  These meetings  can provide

19

an opportunity for the sponsor to share information about the data  gathered to date, for  the FDA to
provide advice, and for the sponsor and  FDA to reach  agreement on  the next phase  of  development.
Sponsors typically use the End of Phase  II meeting  to  discuss  their Phase II  clinical results and present
their plans for the pivotal Phase III clinical  trial that they believe will support  approval of the new
drug. If this type of discussion occurs,  a  sponsor may be able to request a  Special  Protocol Assessment,
or SPA, the purpose of which is to reach  agreement with  the FDA on the design  of  the Phase  III
clinical trial protocol design and analysis that  will form  the primary basis  of  an efficacy claim.

According to FDA guidance for industry on  the SPA  process, a sponsor that meets the

prerequisites may make a specific request for  a special protocol assessment  and provide  information
regarding the design and size of the proposed clinical trial.  The  FDA is required  to  evaluate the
protocol within 45  days of the request to assess whether  the proposed trial  is adequate, and  that
evaluation may result in discussions and  a request for  additional  information. A SPA request  must  be
made before the proposed trial begins, and all open issues must  be  resolved  before  the trial begins. If a
written agreement is reached, it will  be  documented and made part of the record. The agreement  will
be binding on the  FDA and may not  be  changed by the  sponsor  or the FDA  after the trial begins
except with the written agreement of the  sponsor and the FDA or if the FDA determines that a
substantial scientific issue essential to  determining the safety or efficacy of the drug was identified  after
the testing began. If the sponsor makes  any unilateral  changes  to  the approved protocol,  the agreement
will be invalidated.

Concurrent with clinical trials, companies usually complete additional animal studies and  must  also
develop additional information about the  chemistry and physical characteristics of the drug and finalize
a process for manufacturing the product in commercial quantities in  accordance with cGMP
requirements. The manufacturing process must be capable  of consistently  producing quality batches of
the product candidate and, among other things,the  manufacturer must  develop  methods for testing  the
identity, strength, quality and purity of the final drug. Additionally,  appropriate  packaging must be
selected  and tested and stability studies must  be  conducted  to  demonstrate  that  the product candidate
does not undergo unacceptable deterioration over its shelf life.

While the IND is active and before approval, progress reports summarizing  the results  of  the
clinical trials and nonclinical studies performed since the  last progress report  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.

There are also requirements governing the reporting  of ongoing clinical trials and  completed trial
results to public registries. Sponsors of certain clinical trials  of FDA-regulated products  are required  to
register and disclose specified clinical  trial information, which is  publicly available at
www.clinicaltrials.gov. Information related  to  the product, patient population, phase of  investigation,
trial sites and investigators and other  aspects of  the clinical trial  is then  made public as  part of the
registration. Sponsors are also obligated to discuss the  results of their  clinical trials after  completion.
Disclosure of the results of these trials  can be delayed until  the new product or new indication being
studied has been approved. However, there are evolving rules and increasing requirements for
publication of all trial-related information, and it is possible that data and other information from trials
involving drugs that never garner approval could  require disclosure in  the future.

U.S. Review and Approval Processes

The results of product development, preclinical and other non-clinical studies and clinical trials,
along with descriptions of the manufacturing process,  analytical tests conducted on the chemistry  of the

20

drug, proposed labeling, and other relevant  information  are submitted  to  the  FDA as part of an NDA
or BLA requesting approval to market  the product. The submission of an NDA or BLA  is subject to
the payment of user fees; a waiver of  such fees may be obtained  under certain limited circumstances.
The FDA reviews all NDAs and BLAs submitted to ensure that they  are  sufficiently complete for
substantive review before it accepts them  for filing.  The FDA may request additional information
rather than accept an NDA or BLA  for  filing. In this event, the NDA  or 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. FDA may refer the NDA or  BLA  to  an advisory  committee for review, evaluation  and
recommendation as to whether the application should be approved and  under what conditions.  The
FDA is not bound by the recommendation of an advisory  committee, but it  generally  follows  such
recommendations. The approval process  is lengthy  and  often  difficult, and  the FDA may refuse  to
approve an NDA or BLA if the applicable regulatory criteria  are not satisfied or  may require
additional clinical or other data and information. Even  if such data and  information  is submitted,  the
FDA may ultimately decide that the  NDA  or BLA does not satisfy  the criteria for  approval. Data
obtained from clinical trials are not always conclusive and  the FDA may interpret data differently than
we interpret the same data. The FDA  may issue  a complete response  letter,  which may require
additional clinical or other data or impose other conditions that must be met in  order  to  secure  final
approval of the NDA or BLA, or an approved  letter following satisfactory completion of all aspects of
the review process. The FDA reviews an  NDA to determine, among other things, whether a  product is
safe and effective for its intended use and  whether its manufacturing is  cGMP-compliant to assure  and
preserve the product’s identity, strength, quality and purity. The FDA reviews a  BLA to determine,
among other things whether the product is safe, pure and potent  and  the  facility  in which it is
manufactured, processed, packed or  held meets standards designed  to  assure  the product’s  continued
safety, purity and potency. Before approving an NDA  or BLA, the FDA will inspect  the facility or
facilities where the product is manufactured.

NDAs or BLAs receive either standard or priority  review. A drug representing a significant

improvement in treatment, prevention or  diagnosis of disease may  receive priority review.  Priority
review for an NDA for a new molecular  entity and original BLAs  will be 6  months from  the date that
the NDA or BLA is filed. In addition,  products studied for their safety and effectiveness in  treating
serious or life-threatening illnesses and that provide  meaningful  therapeutic benefit over  existing
treatments may receive accelerated approval and may be approved on the  basis of adequate and
well-controlled clinical trials establishing  that  the drug product has an  effect on a  surrogate endpoint
that is reasonably likely to predict clinical benefit or on  the basis  of  an effect on  a clinical  endpoint
other than survival or irreversible morbidity. As a condition of approval, the FDA  may require that a
sponsor  of a drug receiving accelerated  approval  perform  adequate and well-controlled Phase  IV
clinical trials. Priority review and accelerated approval do  not  change the standards  for approval,  but
may expedite the approval process.

After the FDA evaluates an NDA or BLA, it will issue  an approval letter or a Complete Response

Letter. An approval letter authorizes  commercial marketing of the drug with prescribing  information
for specific indications. A Complete Response Letter indicates that the  review cycle of the application
is complete and the application will not  be approved in its present form.  A Complete Response Letter
usually describes the specific deficiencies  in  the NDA or  BLA identified by the FDA and  may require
additional clinical data, such as an additional pivotal  Phase III trial or other significant  and
time-consuming requirements related  to  clinical trials, nonclinical studies or manufacturing. If a
Complete Response Letter is issued,  the sponsor must resubmit the NDA or BLA,  addressing all of the
deficiencies identified in the letter, or withdraw the application. Even  if such data and  information are
submitted, the FDA may decide that  the  NDA  or BLA does not satisfy the criteria for  approval.

21

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. In addition, the  FDA may require  a  sponsor to conduct  Phase IV
testing which involves clinical trials designed to further  assess  a  drug’s safety and effectiveness after
NDA  or  BLA approval, and may require testing and surveillance programs to monitor  the safety of
approved products which have been commercialized. The FDA may  also place other  conditions on
approval including the requirement for  a risk  evaluation and mitigation strategy,  or REMS, to assure
the safe use of the drug. If the FDA concludes a REMS is needed, the  sponsor of the NDA must
submit a proposed REMS. The FDA will  not approve  the NDA without an approved  REMS,  if
required. A REMS could include medication  guides,  physician communication plans  or elements  to
assure safe use, such as restricted distribution methods, patient registries and other risk minimization
tools. Any of these limitations on approval or marketing could restrict  the commercial promotion,
distribution, prescription or dispensing  of products.  Marketing approval  may be withdrawn for
non-compliance with regulatory requirements or  if  problems occur following initial marketing.

The Food and Drug Administration Safety and Innovation Act, or FDASIA, made permanent the

Pediatric Research Equity Act, or PREA,  which requires a sponsor to conduct pediatric clinical  trials
for most drugs and biologics, for a new active ingredient, new indication, new dosage form, new dosing
regimen or new route of administration.  Under PREA,  original NDAs, BLAs and  supplements  thereto,
must contain a pediatric assessment unless the  sponsor  has received a deferral  or waiver.  The  required
assessment must evaluate the safety and  effectiveness of the product for  the claimed indications in all
relevant pediatric subpopulations and  support dosing and administration for  each  pediatric
subpopulation for which the product  is  safe and effective. The sponsor  or FDA  may request a deferral
of pediatric clinical trials for some or all  of the pediatric  subpopulations. A  deferral may be granted for
several reasons, including a finding that the drug or biologic is ready for approval  for use in adults
before pediatric clinical trials are complete or that  additional  safety or effectiveness data needs to be
collected before the pediatric clinical trials begin. The FDA must send a non-compliance letter to any
sponsor  that fails to submit the required assessment, keep  a deferral  current or fails to submit a
request for approval of a pediatric formulation.

Patent Term Restoration and Marketing  Exclusivity

Depending upon the timing, duration and specifics of FDA approval of our drugs, some 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. The Hatch-
Waxman Amendments permit a patent restoration term of up to five years as compensation for  patent
term lost during product development and  the FDA regulatory review process. However, patent term
restoration cannot  extend the remaining  term of a patent beyond a total of 14 years from the  product’s
approval date. The patent term restoration period  is generally one-half the  time between  the effective
date  of  an IND, and the submission  date of an NDA  or BLA, plus  the time  between  the submission
date  of  an NDA or BLA and the approval of that application. Only one patent applicable to an
approved drug is eligible for the extension, and the  extension must  be  applied for  prior to expiration  of
the patent. The United States Patent and Trademark Office, in consultation  with the FDA,  reviews and
approves the application for any patent term extension  or restoration. In the  future, we intend  to  apply
for restorations of patent term for some of  our currently owned or licensed patents to add  patent  life
beyond their current expiration date,  depending on the expected length of clinical trials and other
factors involved in the filing of the relevant NDA.

Pediatric exclusivity is a type of marketing exclusivity  available in the U.S. The FDASIA made
permanent the Best Pharmaceuticals for Children Act, or BPCA, which  provides for  an additional  six
months of marketing exclusivity if a sponsor conducts clinical trials in  children in response to a  written
request from the FDA, or a Written Request. If the  Written Request does  not  include clinical  trials in

22

neonates, the FDA is required to include its rationale for not requesting those clinical trials. The FDA
may request studies on approved or  unapproved indications in  separate  Written Requests.  The  issuance
of a Written Request does not require  the sponsor to undertake  the described clinical trials. To date,
we have not received any Written Requests.

Biologics Price Competition and Innovation  Act of 2009

On March 23, 2010, President Obama signed into law the Patient Protection  and Affordable  Care

Act which included the Biologics Price  Competition  and Innovation  Act  of  2009, or BPCIA. The
BPCIA amended the PHSA to create an  abbreviated approval pathway for two  types of ‘‘generic’’
biologics—biosimilars and interchangeable biologic products, and provides for a twelve-year data
exclusivity period for the first approved  biological product, or reference product, against which a
biosimilar or interchangeable application is evaluated; however if pediatric  clinical trials  are performed
and accepted by the FDA, the twelve-year  data  exclusivity period  will be extended for  an additional  six
months. A biosimilar product is defined as  one that is highly similar to a reference product
notwithstanding minor differences in  clinically inactive components and for  which there are no clinically
meaningful differences between the biological product  and  the  reference product in terms of the safety,
purity and potency of the product. An interchangeable product  is a biosimilar product  that  may be
substituted for the reference product  without the intervention of the health care provider who
prescribed the reference product.

The biosimilar applicant must demonstrate that the  product is  biosimilar based on  data  from

(1) analytical studies showing that the biosimilar product is highly  similar  to  the reference product;
(2) animal studies (including toxicity);  and (3)  one or more clinical  trials  to  demonstrate  safety, purity
and potency in one or more appropriate  conditions  of use for  which the reference  product is approved.
In addition, the applicant must show that  the biosimilar and  reference  products have  the same
mechanism of action for the conditions of  use on the  label, route of administration, dosage  and
strength, and the production facility must meet standards designed to assure product  safety, purity and
potency.

An application for a biosimilar product may not be submitted until four years after the date on
which  the reference product was first  approved. The first approved interchangeable  biologic product
will be granted an exclusivity period of up to one year after it is first  commercially marketed, but  the
exclusivity period may be shortened under certain circumstances.

The FDA has issued a number of final and draft guidances  in order to implement the law. On

April 28, 2015, the FDA issued the following  three final  guidances:  ‘‘Scientific  Considerations in
Demonstrating Biosimilarity to a Reference  Product,’’ ‘‘Quality Considerations  in Demonstrating
Biosimilarity of a Therapeutic Protein  Product to a  Reference Product,’’  and ‘‘Biosimilars: Questions
and Answers Regarding Implementation  of the  Biologics  Price Competition and  Innovation Act of  2009
Guidance for Industry.’’ The draft guidances include  ‘‘Formal Meetings  between the  FDA and
Biosimilar Biological Product Sponsors or  Applicants’’  issued March 29,  2013, ‘‘Clinical Pharmacology
Data to Support a Demonstration of Biosimilarity  to  a Reference Product’’ issued May 14,  2014,
‘‘Reference Product Exclusivity for Biological Products Filed Under Section  351(a) of the PHS Act’’
issued August 4, 2014, and ‘‘Biosimilars: Additional Questions and Answers Regarding Implementation
of the Price Competition and Innovation Act  of  2009,’’ issued May 12, 2015.

The guidance documents provide FDA’s current thinking on approaches to demonstrating  that  a
proposed biological product is biosimilar  to a reference product. The FDA  intends to issue additional
guidance documents in the future, and has identified considerations in demonstrating interchangeability
to a reference product, labeling and  nonproprietary naming as several of the issues  that  it hopes to
address in calendar year 2015. Nonetheless,  the absence  of  final guidance documents  covering all

23

biosimilars issues does not prevent a  sponsor from seeking licensure of a biosimilar  under the BPCIA,
and the FDA recently approved the first biosimilar  application  in the U.S.

Orphan Drug Designation

Under the Orphan Drug Act, the FDA may grant orphan  drug  designation  to  a drug intended to

treat a rare disease or condition, which is  generally a disease or condition  that  affects fewer  than
200,000 individuals in the U.S., or more than 200,000  individuals  in the  U.S. and for which there  is no
reasonable expectation that the cost of developing and making available in the U.S. a drug for this type
of disease or condition will be recovered from sales in the  U.S.  for that  drug. Orphan drug designation
must be requested before submitting an  NDA or  BLA. After  the FDA grants orphan drug designation,
the identity of the therapeutic agent and  its potential orphan use will  be  disclosed publicly by the  FDA;
the posting will also indicate whether a drug  is no  longer designated as an orphan drug.  More than one
product  candidate may receive an orphan drug  designation  for the  same indication. Orphan drug
designation does not convey any advantage in or shorten the duration of  the regulatory review and
approval process.

If a  product that has orphan drug designation subsequently  receives the  first  FDA approval for the

disease for which it has such designation,  the product  is entitled  to  seven years of  orphan product
exclusivity, except in very limited circumstances. The FDA  issued a final rule,  effective  August  12, 2013,
intended to clarify several regulatory provisions, among which was a  clarification of some of those
limited circumstances. One of the provisions makes clear  that  the FDA will not recognize orphan  drug
exclusive approval if a sponsor fails to demonstrate upon approval  that the drug is  clinically  superior to
a previously approved drug, regardless of whether or not the approved drug was designated an orphan
drug or had orphan drug exclusivity. Thus orphan drug exclusivity also could block the approval of  one
of our products for seven years if a competitor obtains approval of  the same drug as defined  by  the
FDA and we are not able to show the  clinical  superiority of our drug or if our product candidate is
determined to be contained within the  competitor’s product  for the same indication or disease.

The FDA and the European Union granted Orphan  Drug  designation  to  mirvetuximab

soravtansine, or IMGN853, when used  for the  treatment of ovarian cancer.  Orphan drug designation
provides us with seven years of market exclusivity that begins once mirvetuximab soravtansine receives
FDA marketing approval for the use  for which  the orphan  drug status was granted. Orphan medicinal
product  designation provides ImmunoGen with  ten years of market exclusivity that begins once
mirvetuximab soravtansine receives European approval  for the  use for which  it was  granted. We may
pursue these designations for other indications for  other product  candidates intended for  qualifying
patient populations.

Expedited Review and Approval

The FDA has various programs, including Fast Track, priority review, and accelerated  approval,
which  are intended to expedite or simplify the  process for reviewing  drugs, and/or provide  for approval
on the basis of surrogate endpoints. Even if a drug qualifies for one or more  of these  programs,  the
FDA may later decide that the drug no longer  meets  the conditions for qualification or that the  time
period for FDA review or approval will not be shortened.  Generally, drugs that may be eligible  for
these programs are those for serious  or life-threatening conditions, those  with the potential to address
unmet medical needs, and those that offer meaningful benefits over  existing treatments.  For example,
Fast Track is a process designed to facilitate the  development, and expedite the review, of  drugs to
treat serious diseases and fill an unmet  medical  need. The  request may be made  at the time of IND
submission and generally no later than the pre-BLA  or pre-NDA meeting. The  FDA  will  respond
within 60 calendar days of receipt of the request. Priority  review, which  is requested at the time of
BLA or NDA submission, is designed to give  drugs that offer major  advances in treatment  or provide a
treatment where no adequate therapy  exists  an initial  review within  six months  as compared  to  a

24

standard review time of ten months. Although Fast Track and priority  review do not affect the
standards for approval, the FDA will  attempt to facilitate early and frequent meetings  with a sponsor of
a Fast Track designated drug and expedite review of the application for a drug designated for  priority
review. Accelerated approval provides  an earlier approval of  drugs to treat serious  diseases,  and that fill
an unmet medical need based on a surrogate endpoint, which is a laboratory measurement or  physical
sign used as an indirect or substitute  measurement representing a  clinically  meaningful outcome.
Discussions with the FDA about the feasibility of an  accelerated approval typically begin early in the
development of the drug in order to identify,  among  other  things, an appropriate endpoint.  As a
condition of approval, the FDA may  require that a sponsor of a drug receiving accelerated approval
perform post-marketing clinical trials to confirm the appropriateness of  the  surrogate marker trial.

In FDASIA, Congress encouraged the FDA to utilize innovative  and flexible approaches to the
assessment of products under accelerated approval. The law required the FDA to issue  related draft
guidance within a year after the law’s enactment and also promulgate confirming regulatory changes.
The FDA published a final guidance  on  May  30, 2014, entitled ‘‘Expedited Programs  for Serious
Conditions—Drugs and Biologics.’’ One of the expedited programs added  by  FDASIA is that for
Breakthrough Therapy. A Breakthrough  Therapy designation is designed  to expedite the  development
and review of drugs that are intended to treat a serious  condition  where preliminary clinical evidence
indicates that the drug may demonstrate  substantial improvement over available therapy on  a clinically
significant endpoint(s). A sponsor may  request Breakthrough Therapy designation at  the time  that  the
IND is submitted, or no later than at the  end-of-Phase II meeting.  The FDA  will respond to a
Breakthrough Therapy designation request within sixty days of receipt  of the request. A drug that
receives Breakthrough Therapy designation is eligible  for all fast track designation features,  intensive
guidance on an efficient drug development  program, beginning as early as Phase  I  and commitment
from the FDA involving senior managers. FDA has already granted  this designation to at least 60 new
drugs and seven to date have received  approval.

Post-Approval Requirements

Once an approval is granted, the FDA may withdraw the approval if compliance with regulatory

standards is not maintained or if problems  occur after  the product reaches the market. Later discovery
of previously  unknown problems with a product  may result  in restrictions  on the  product or even
complete withdrawal of the product from the  market.  After approval,  some types  of changes to the
approved product, such as adding new indications,  certain manufacturing changes and additional
labeling claims, are subject to further FDA  review and  approval. Drug manufacturers and other entities
involved in the manufacture and distribution of approved drugs 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  and other laws and
regulations. We rely, and expect to continue to rely, on  third  parties for the production of clinical and
commercial quantities of our products. Future inspections by the  FDA and other regulatory agencies
may identify compliance issues at the facilities of our contract manufacturers that may disrupt
production or distribution, or require substantial resources to correct.

Any drug products manufactured or  distributed  by us  or our partners pursuant to FDA approvals

are subject to continuing regulation by  the FDA, including, among other  things, record-keeping
requirements, reporting of adverse experiences with  the drug, providing  the FDA with  updated safety
and efficacy information, drug sampling  and  distribution requirements, complying with certain
electronic records and signature requirements, and complying with FDA  promotion and  advertising
requirements. FDA strictly regulates labeling,  advertising,  promotion  and other  types of information on
products that are placed on the market.  Drugs  may be promoted  only for the  approved indications and
in accordance with the provisions of  the approved label.

25

From time to time, legislation is drafted,  introduced  and  passed in  Congress that could significantly

change the statutory provisions governing the approval,  manufacturing  and  marketing of  products
regulated by the FDA. It is impossible to predict whether further legislative  changes will  be  enacted, or
FDA regulations, guidance or interpretations changed  or what the impact of such  changes, if  any, may
be.

Foreign Regulation

In addition to regulations in the U.S.,  we will be subject  to  a  variety of foreign regulations
governing clinical trials and commercial sales and  distribution of our products. Whether  or not we
obtain FDA approval for a product, we must  obtain  approval by the comparable regulatory  authorities
of foreign countries or economic areas,  such  as the European Union,  before we may commence  clinical
trials or market products in those countries or areas. The approval process  and requirements governing
the conduct of clinical trials, product licensing, pricing and reimbursement vary greatly from place  to
place, and the time may be longer or shorter than that required for FDA approval.

Under European Union regulatory systems, a company may submit marketing authorization
applications either under a centralized  or  decentralized  procedure. The centralized procedure, which is
compulsory for medicinal products produced by biotechnology  or those medicinal  products containing
new active substances for specific indications  such as the  treatment of  AIDS, cancer, neurodegenerative
disorders, diabetes, viral diseases and  designated orphan medicines, and optional for other medicines
which  are highly innovative. Under the  centralized procedure,  a marketing application is  submitted to
the European Medicines Agency where it  will  be  evaluated by  the Committee  for Medicinal Products
for Human Use and a favorable opinion  typically results in the  grant by  the European Commission  of a
single marketing authorization that is valid for  all  European Union member states  within 67  days of
receipt of the opinion. The initial marketing  authorization is valid for  five  years,  but once  renewed is
usually valid for an unlimited period.  The  decentralized procedure provides for approval by one or
more ‘‘concerned’’ member states based on an  assessment of an  application  performed by one  member
state, known as the ‘‘reference’’ member state.  Under the  decentralized  approval procedure,  an
applicant submits an application, or dossier,  and related materials to the  reference member state and
concerned member states. The reference member state  prepares a draft assessment and drafts  of  the
related materials within 120 days after receipt of  a valid application. Within 90 days  of receiving  the
reference member state’s assessment  report, each concerned member  state must decide whether to
approve the assessment report and related materials.  If a member state does  not  recognize the
marketing authorization, the disputed  points are  eventually referred to the European Commission,
whose decision is binding on all member  states.

As in the U.S., we may apply for designation of a product as  an  orphan drug  for the  treatment of

a specific indication in the European  Union  before  the application for  marketing  authorization is made.
Orphan  drugs in Europe enjoy economic and marketing  benefits, including up to 10 years of market
exclusivity for the approved indication  unless another applicant can show  that its product is safer, more
effective or otherwise clinically superior to the orphan-designated  product.

Reimbursement

Sales of pharmaceutical products depend in  significant part on the availability  of  third-party

reimbursement. Third-party payors include  government  healthcare programs such  as Medicare,
managed care providers, private health  insurers and other organizations. We anticipate  third-party
payors will provide reimbursement for  our products.  However, these third-party payors are increasingly
challenging the price and examining the cost-effectiveness  of medical  products and services. In addition,
significant uncertainty exists as to the reimbursement  status of  newly  approved healthcare  products. We
may need to conduct expensive pharmacoeconomic studies in order to demonstrate the
cost-effectiveness of our products. Our  product  candidates may not be considered cost-effective. It is

26

time consuming and expensive for us  to  seek reimbursement from third-party payors. Reimbursement
may not be available or sufficient to allow us to sell  our  products on a competitive and profitable basis.

Medicare is a federal healthcare program administered by the federal government that covers
individuals age 65 and over as well as individuals  with certain  disabilities. Drugs may  be  covered under
one or more sections of Medicare depending on the nature  of  the drug and the conditions  associated
with and site of administration. For example, under  Part D,  Medicare beneficiaries may enroll  in
prescription drug plans offered by private entities which provide coverage  for outpatient  prescription
drugs. Part D plans include both stand-alone prescription drug benefit plans and prescription drug
coverage as a supplement to Medicare Advantage plans. Unlike Medicare  Part A and  B, Part D
coverage is not standardized. Part D prescription drug plan  sponsors are not required to pay for all
covered Part D drugs, and each drug plan  can develop its own  drug  formulary  that  identifies which
drugs it will cover and at what tier or level.

Medicare Part B covers most injectable drugs given in an in-patient  setting and some drugs
administered by a  licensed medical provider  in hospital outpatient  departments and  doctors’  offices.
Medicare Part B is administered by Medicare Administrative Contractors, which generally have the
responsibility of making coverage decisions. Subject to certain payment adjustments  and limits,
Medicare generally pays for a Part B covered drug based on a  percentage of manufacturer-reported
average sales price which is regularly  updated. We believe that  most  of  our drugs,  when approved, will
be subject to the Medicare Part B rules.

The American Recovery and Reinvestment Act of 2009  provides funding for the federal

government to compare the effectiveness  of different treatments for the same illness. A  plan for this
research will be developed by the Department  of  Health and Human  Services, the Agency for
Healthcare Research and Quality and  the  National  Institutes for  Health, and periodic reports on the
status of the research and related expenditures will be made to Congress. Although the results of the
comparative effectiveness studies are not intended to mandate coverage policies for public or private
payors, it is not clear what effect, if any, the  research will  have on the sales of our product  candidates,
if any such product or the condition  that it is  intended to treat is  the subject of  a study. It  is also
possible that comparative effectiveness  research demonstrating benefits in  a competitor’s product could
adversely affect the sales of our product  candidates. If third-party payors  do not consider our products
to be cost- effective compared to other available therapies, they may not cover our products after
approval as a benefit under their plans  or, if  they  do,  the level of  payment may not be sufficient to
allow us to sell our products on a profitable basis.

We  expect that there will continue to  be  a number of federal  and state proposals  to  implement

governmental pricing controls and limit the growth of healthcare costs, including the cost of
prescription drugs. For example, the Patient  Protection and Affordable Care Act,  as amended by the
Health Care and Education Affordability  Reconciliation  Act  of  2010 (collectively, ACA) enacted  in
March 2010, was expected to have a significant  impact  on the health  care industry.  ACA has resulted in
expanded coverage for the uninsured  and is expected to help contain  overall healthcare costs. With
regard to pharmaceutical products, among  other things,  ACA is expected to expand and  increase
industry rebates for drugs covered under Medicaid  programs and  make changes  to  the coverage
requirements under the Medicare Part D  program. We cannot  predict  the impact of ACA on
pharmaceutical companies as many of  the ACA  reforms require  the promulgation of detailed
regulations implementing the statutory provisions which has not yet occurred. In  addition,  although the
United States Supreme Court upheld the  constitutionality of most of the  ACA, some states have stated
their intentions to not implement certain  sections of ACA  and  some members of Congress are still
working to repeal ACA. These challenges  add to the uncertainty of the  changes enacted as  part of
ACA.

27

In addition, in some foreign countries, the  proposed pricing for a drug must be approved before  it

may be lawfully marketed. The requirements governing drug pricing vary widely from country to
country. For example, the European  Union provides  options for its member states  to  restrict the range
of medicinal products for which their national  health insurance  systems  provide reimbursement and to
control the prices of medicinal products for human  use. A  member state may  approve a specific price
for the medicinal product or it may instead adopt a  system of direct  or indirect controls on  the
profitability of the company placing the  medicinal product  on the  market.  There can be no assurance
that any country that has price controls or reimbursement limitations for pharmaceutical products  will
allow favorable reimbursement and pricing arrangements for  any of our products. Historically, products
launched in the European Union do  not  follow price structures of  the  U.S. and generally tend to be
significantly lower.

Research and Development Spending

During  each of the three years ended  June 30, 2015,  2014 and  2013, we spent approximately
$111.8 million, $107.0 million and $87.1  million, respectively, on research  and development  activities.

Raw Materials and Manufacturing

We  procure certain raw material components of finished conjugate,  including antibodies,  cytotoxic
agents, and linker, for ourselves and  on  behalf of our collaborators. In order to meet our commitments
to our collaborators as well as our own  needs, we  are required to enter into  agreements with third
parties to produce these components well  in  advance of our production needs. Our principal  suppliers
for these components include Boehringer  Ingelheim, BSP Pharmaceuticals  S.r.l., SAFC, Inc., Carbogen
Amcis and Societ`a Italiana Corticosteroidi S.r.l.

In addition, we operate a conjugate manufacturing facility. A portion  of  the cost  of operating this

facility, including the cost of manufacturing personnel, is incurred to conjugate material on behalf of
our  collaborators for which we receive  payments based on the number of batches of preclinical and
clinical materials produced on their behalf.  Over the past few years, we have  expanded and upgraded
the capabilities of  our manufacturing facility.

Employees

As of June 30, 2015, we had 317 full-time employees,  of  whom 272 were  engaged  in research and

development activities. Of the 272 research and development employees, 134 employees hold post-
graduate degrees, of which 61 hold Ph.D. degrees and six  hold M.D. degrees. We consider  our  relations
with our employees to be good. None of  our employees is covered by  a collective bargaining
agreement.

We  have entered into confidentiality agreements with all  of  our employees, members of our board
of directors and consultants. Further, we  have entered into assignment of invention agreements  with all
of our employees.

Third-Party Trademarks

Herceptin and Kadcyla are registered trademarks of Genentech. Rituxan  is a registered trademark

of Biogen Inc. Probody is a trademark of CytomX Therapeutics, Inc.

28

Item 1A. Risk Factors

THE RISKS AND UNCERTAINTIES  DESCRIBED  BELOW ARE THOSE THAT WE  CURRENTLY
BELIEVE MAY MATERIALLY AFFECT  OUR COMPANY. ADDITIONAL  RISKS AND
UNCERTAINTIES THAT WE ARE UNAWARE OF OR  THAT WE CURRENTLY DEEM
IMMATERIAL ALSO MAY BECOME IMPORTANT  FACTORS  THAT  AFFECT  OUR COMPANY.

We have a history of operating losses and expect to incur significant  additional operating losses.

We  have generated operating losses since our inception. As  of June 30, 2015,  we had an

accumulated deficit of $708.9 million.  For the years ended June 30, 2015, 2014, and 2013, we generated
losses of $60.7 million, $71.4 million  and $72.8  million,  respectively. We  may never  be  profitable.  We
expect to incur substantial additional  operating expenses over the  next several years as  our research,
development, preclinical testing, clinical trials and collaborator support activities continue. We intend to
continue to invest significantly in our  product candidates.  Further,  we expect to invest  some of  our
resources to support our existing collaborators  as they  work  to  develop, test and commercialize ADC
compounds. We or our collaborators  may encounter technological  or  regulatory difficulties as part of
this  development and commercialization process  that  we cannot overcome  or remedy. We  may also
incur substantial marketing and other costs in the  future if we decide  to  establish marketing and  sales
capabilities to commercialize our product  candidates. Our  revenues to date have been primarily  from
upfront and milestone payments, research and  development support and clinical materials
reimbursement from our collaborative  partners and increasingly from royalties received from the
commercial sales of Kadcyla. We do  not expect to generate  revenues  from  the commercial sale of our
internal product candidates in the near future, and we may never  generate  revenues from  the
commercial sale of internal products.  Even  if we do successfully develop products that can be marketed
and sold commercially, we will need to generate significant revenues from those  products to achieve
and maintain profitability. Even if we  do become  profitable, we may  not  be  able to sustain or increase
profitability on a quarterly or annual  basis.

If we are unable to obtain additional  funding when needed, we may have to delay  or  scale back some
of our programs or grant rights to third parties to  develop and  market our  product candidates.

We  will continue to expend substantial  resources developing new and existing  product candidates,

including costs associated with research  and development, acquiring new technologies,  conducting
preclinical studies and clinical trials, obtaining regulatory approvals and manufacturing products as well
as providing certain support to our collaborators  in the development of their  products. We  believe that
our  current working capital and expected  future payments from our existing  collaboration  arrangements
will be sufficient to meet our current and projected  operating and  capital requirements through fiscal
2017. However, we cannot provide assurance that such collaborative agreement funding will,  in fact,  be
received. Should such future collaborator  payments not be earned and paid  as currently anticipated,  we
expect we could seek additional funding  from other sources. We may need additional  financing  sooner
due to a number of other factors as well,  including:

(cid:129) if  either we incur higher than expected  costs or  we or  any of our  collaborators experience slower
than expected progress in developing product candidates and obtaining regulatory approvals;

(cid:129) acquisition of technologies and other  business opportunities that  require financial commitments.

Additional funding may not be available to us on favorable terms, or  at all. We  may raise

additional funds through public or private  financings, collaborative arrangements or other
arrangements. Debt financing, if available, may involve covenants that could restrict our business
activities. If we are unable to raise additional funds through equity or  debt financing when needed, we
may be required to delay, scale back or eliminate expenditures for some of our development  programs
or grant rights to develop and market  product candidates  that we would  otherwise prefer to internally

29

develop and market. If we are required  to  grant such rights, the ultimate value  of  these  product
candidates to us may be reduced.

If our ADC technology does not produce  safe, effective and  commercially viable products,  our  business
will be severely harmed.

Our ADC technology yields novel product candidates for the  treatment of cancer. To  date, only

one ADC using our technology, Kadcyla, has  obtained marketing  approval. Our ADC product
candidates and/or our collaborators’ ADC  product candidates may not prove to be safe, effective or
commercially viable treatments for cancer  and our ADC technology may not result in any  future
meaningful benefits to us or for our current or  potential collaborative partners. Furthermore,  we are
aware of only two other compounds that  are a conjugate  of  an antibody and a cytotoxic small molecule
that have obtained marketing approval  by the  FDA and are based  on technology  similar to our ADC
technology. One of these products was  later  taken  off the  market  by its owner due to toxicity concerns.
If our ADC technology fails to generate  product candidates  that are safe,  effective  and commercially
viable treatments for cancer or such product candidates  fail to obtain FDA approval,  our business will
be severely harmed.

Clinical trials for our and our collaborative partners’ product  candidates will be lengthy  and expensive
and their outcome is uncertain.

Before obtaining regulatory approval  for the  commercial sale  of  any product candidates,  we and
our  collaborative partners must demonstrate  through clinical testing that our product candidates  are
safe and effective for use in humans.  Conducting  clinical trials  is a time-consuming, expensive and
uncertain process and typically requires  years  to  complete. In  our industry,  the results from  preclinical
studies and early clinical trials often are not predictive  of  results obtained in later-stage clinical trials.
Some compounds that have shown promising results in preclinical  studies or  early clinical trials
subsequently fail to establish sufficient  safety and  efficacy data necessary  to obtain regulatory approval.
At any time during the clinical trials, we,  our collaborative  partners,  or the FDA might delay or halt
any clinical trials of our product candidates for  various reasons,  including:

(cid:129) occurrence of unacceptable toxicities or side effects;

(cid:129) ineffectiveness of the product candidate;

(cid:129) insufficient drug supply;

(cid:129) negative or inconclusive results from the clinical trials,  or  results that necessitate  additional

studies  or clinical trials;

(cid:129) delays in obtaining or maintaining required approvals from institutions,  review boards  or other

reviewing entities at clinical sites;

(cid:129) delays in patient enrollment;

(cid:129) insufficient funding or a reprioritization of financial or  other resources; or

(cid:129) other reasons that are internal to the businesses of our collaborative partners, which  they may

not share with us.

Any failure or substantial delay in successfully completing  clinical  trials  and  obtaining  regulatory
approval for our product candidates or  our collaborative partners’ product candidates could severely
harm our business.

30

We and our collaborative partners are  subject to  extensive government regulations and  we and  our
collaborative  partners may not be able  to  obtain necessary regulatory approvals.

We  and our collaborative partners may not receive  the regulatory  approvals necessary to

commercialize our product candidates, which would cause  our business to be severely harmed.
Pharmaceutical product candidates, including those in development  by us  and our collaborative
partners, are subject to extensive and rigorous government regulation.  The FDA regulates, among other
things, the development, testing, manufacture, safety,  record-keeping,  labeling, storage, approval,
advertising, promotion, sale and distribution  of  pharmaceutical products. If  our  potential  products or
our  collaborators’ potential products are marketed  abroad, they will also  be  subject to extensive
regulation by foreign governments. The  regulatory review and approval process, which includes
preclinical studies and clinical trials of  each  product candidate, is lengthy,  complex, expensive and
uncertain. Securing FDA approval requires the  submission  of extensive preclinical and clinical  data  and
supporting information to the FDA for  each indication  to  establish the product candidate’s safety  and
efficacy. Data obtained from preclinical studies and clinical trials are susceptible  to  varying
interpretation, which may delay, limit or prevent regulatory approval.  The approval process may take
many  years to complete and may involve  ongoing requirements for post-marketing studies. Any FDA or
other regulatory approvals of our or  our  collaborative partners’  product candidates, once obtained, may
be withdrawn. The effect of government regulation may be to:

(cid:129) delay marketing of potential products for a considerable period of time;

(cid:129) limit the indicated uses for which potential products  may  be  marketed;

(cid:129) impose costly requirements on our  activities; and

(cid:129) place us at a competitive disadvantage to other pharmaceutical and biotechnology  companies.

We  may encounter delays or rejections in the  regulatory approval process  because of additional
government regulation from future legislation or administrative action  or changes in  FDA policy during
the period of product development, clinical trials and  FDA regulatory  review. Failure  to  comply with
FDA or other applicable regulatory requirements may result  in criminal prosecution,  civil  penalties,
recall or seizure of products, total or  partial suspension of production or  injunction, as well as  other
regulatory action against our product candidates or  us. Outside the  U.S., our ability to market a
product  is contingent upon receiving clearances  from the appropriate regulatory authorities. The
foreign regulatory  approval process includes similar  risks to those associated with the FDA approval
process. In addition, we are, or may become,  subject to various  federal, state and  local laws, regulations
and recommendations relating to safe working conditions,  laboratory and manufacturing practices, the
experimental use of animals and the use and disposal  of  hazardous substances, including radioactive
compounds and infectious disease agents, used in  connection with  our research  work. If  we fail to
comply  with the laws and regulations pertaining to our business, we  may be subject to sanctions,
including the temporary or permanent suspension of operations,  product recalls, marketing restrictions
and civil and criminal penalties.

Our and our collaborative partners’ product candidates will remain subject  to ongoing regulatory
review even if they receive marketing  approval. If we  or our  collaborative partners fail to comply with
continuing regulations, these approvals  could be lost  and the  sale  of our or our collaborative partners’
products could be suspended.

Even if we or our collaborative partners receive  regulatory approval to market  a particular product

candidate, the approval could be conditioned  on us  or our  collaborative  partners conducting  costly
post-approval studies or could limit the  indicated uses included in product labeling.  Moreover, the
product  may later cause adverse effects that limit or  prevent its widespread use, force us  or our
collaborative partners to withdraw it from  the  market  or impede  or  delay our or  our collaborative

31

partners’ ability to obtain regulatory  approvals in  additional countries.  In addition, the  manufacturer of
the product and its facilities will continue  to  be  subject to FDA review  and  periodic  inspections to
ensure adherence to applicable regulations. After  receiving marketing approval, the manufacturing,
labeling, packaging, adverse event reporting,  storage, advertising, promotion and  record-keeping related
to the product remain subject to extensive regulatory  requirements.  We or our collaborative partners
may be slow to adapt, or we or our collaborative partners may never adapt,  to  changes in existing
regulatory requirements or adoption  of  new regulatory requirements.

If we  or our collaborative partners fail to comply with  the regulatory  requirements of the  FDA and
other applicable U.S. and foreign regulatory authorities, or if  previously unknown problems with our  or
our  partners’ products, manufacturers or  manufacturing processes are discovered, we could be subject
to administrative or judicially imposed sanctions, including:

(cid:129) restrictions on the products, manufacturers or manufacturing  processes;

(cid:129) warning letters;

(cid:129) civil or criminal penalties;

(cid:129) fines;

(cid:129) injunctions;

(cid:129) product seizures or detentions;

(cid:129) import bans;

(cid:129) voluntary or mandatory product recalls and publicity requirements;

(cid:129) suspension or withdrawal of regulatory approvals;

(cid:129) total or partial suspension of production;  and

(cid:129) refusal to approve pending applications for marketing approval  of  new  drugs or supplements to

approved applications.

Any one of these could have a material adverse  effect on  our business or  financial condition.

If our collaborative partners fail to perform their obligations under our agreements with them,  or
determine not to continue with clinical trials for  particular product candidates, our business  could be
severely impacted.

Our strategy for the development and commercialization of our product candidates depends, in
large part, upon the formation and maintenance of collaborative arrangements. Collaborations provide
an opportunity for us to:

(cid:129) generate cash flow and revenue;

(cid:129) fund some of the costs associated with our internal research and development,  preclinical

testing, clinical trials and manufacturing;

(cid:129) seek and obtain regulatory approvals  faster than we  could  on our own;

(cid:129) successfully commercialize existing  and future  product candidates; and

(cid:129) secure access to targets which, due to intellectual property restrictions, would otherwise be

unavailable to our technology.

If we  fail to secure or maintain successful  collaborative  arrangements, the  development and
marketing of compounds that use our technology may be delayed, scaled back or otherwise  may not
occur. In addition, we may be unable to negotiate other collaborative arrangements  or, if  necessary,

32

modify  our existing arrangements on acceptable  terms. We cannot  control the amount and timing of
resources our collaborative partners may  devote to our product candidates. Our  collaborative partners
may separately pursue competing product candidates, therapeutic approaches or  technologies to
develop treatments for the diseases targeted  by us  or our collaborative efforts, or  may decide,  for
reasons not known to us, to discontinue  development of product candidates under our agreements  with
them. Any of our collaborative partners  may  slow or discontinue the  development of a product
candidate covered by a collaborative arrangement for reasons that  can include, but are not limited to:

(cid:129) a change in the collaborative partner’s strategic focus as a  result of merger, management

changes, adverse business events, or other causes;

(cid:129) a change in the priority of the product candidate relative to other programs in the collaborator’s

pipeline;

(cid:129) a reassessment of the patent situation related to the compound  or  its target;

(cid:129) a change in the anticipated competition for the product  candidate;

(cid:129) preclinical studies and clinical trial  results; and

(cid:129) a reduction in the financial resources  the collaborator can  or  is willing to apply to the

development of new compounds.

Even if our collaborative partners continue  their  collaborative arrangements with  us, they  may

nevertheless determine not to actively  pursue the  development or commercialization of any resulting
products. Also, our collaborative partners may fail to perform their obligations under  the collaborative
agreements or may be slow in performing their obligations. Our collaborative partners can terminate
our  collaborative agreements under certain conditions. The decision to advance a  product that is
covered by a collaborative agreement through clinical trials and ultimately to commercialization is in
the discretion of our collaborative partners. If  any  collaborative partner were to terminate  or breach
our  agreements, fail to complete its obligations to us in a  timely manner, or decide to discontinue its
development of a product candidate, our  anticipated revenue from the agreement  and from  the
development and commercialization of the  products would  be  severely limited. If  we are  not  able to
establish additional collaborations or  any  or all of  our  existing collaborations are terminated and we are
not able to enter into alternative collaborations on acceptable  terms, or at all, our continued
development, manufacture and commercialization  of  our  product candidates  could  be  delayed or  scaled
back as  we may not have the funds or  capability to continue these activities. If our  collaborators  fail to
successfully develop and commercialize ADC  compounds, our business prospects  would be severely
harmed.

We depend on a small number of collaborators for a substantial portion  of our revenue.  The  loss of, or
a material reduction in activity by, any  one of  these collaborators could  result  in a substantial  decline
in our revenue.

We  have and will continue to have collaborations  with a limited  number of companies. As a  result,

our  financial performance depends on the  efforts and overall success of these companies. Also, the
failure of any one of our collaborative  partners  to  perform its obligations  under its agreement with us,
including making any royalty, milestone or  other payments to us,  could have an adverse effect on our
financial condition. Further, any material reduction by any one of our collaborative partners in its level
of commitment of resources, funding, personnel,  and  interest in continued development under its
agreement with us could have an adverse  effect  on our financial condition. Also, if consolidation trends
in the healthcare industry continue, the number  of  our  potential  collaborators could decrease, which
could have an adverse impact on our development efforts.  If a present or  future collaborator of ours
were to be involved in a business combination, the collaborator’s continued pursuit  and emphasis on
our  product development program could  be delayed,  diminished or terminated.

33

Royalties from commercial sales of Kadcyla will  likely  fluctuate and will impact  our reported royalty
revenues and rights to receive future  payments  from the commercial sale of Kadcyla  under our license
agreement with Roche and our royalty purchase  agreement  with  Immunity Royalty Holdings,  L.P.

Roche’s Kadcyla is currently the only  product  with respect to which we  are entitled to receive
royalties that has received marketing  approval. In April 2015, Immunity Royalty  Holdings, L.P. paid  us
$200 million to purchase our right to receive 100% of the  royalty payments  on commercial sales of
Kadcyla arising under our development  and commercialization license with  Roche,  through its
Genentech unit, until Immunity Royalty Holdings has  received aggregate Kadcyla royalties equal to
$235 million or $260 million, depending  on when  the aggregate Kadcyla  royalties received by Immunity
Royalty Holdings reach a specified milestone. Once  the applicable threshold is met,  if  ever, we  will
thereafter receive 85% and Immunity Royalty Holdings  will  receive 15% of  the Kadcyla royalties for
the remaining royalty term. These royalty revenues may fluctuate considerably because they  depend
upon, among other things, the rate of growth of sales of Kadcyla as  well as the  mix  of U.S.-based sales
and ex-U.S.-based sales and our valid patent claims. While the royalty  purchase  transaction with
Immunity Royalty Holdings has mitigated any impact that fluctuations  in these  royalty revenues may
have on our financial condition, negative fluctuations could  delay, diminish  or eliminate our  right to
resume receiving 85% of the royalty in the  future, as described above.

Royalty rates under our license agreements  with  our  collaborators may vary over the  royalty  term
depending on our  intellectual property  rights and the presence of competing  products.

Most of our license agreements with our collaborators  provide that the royalty rates  are subject to

downward adjustment in the absence  of  ImmunoGen patent rights covering various aspects of  the
manufacture, use or sale of the products developed  under such licenses,  or in the presence of
competition from certain third-party  products. For  example,  we  expect the royalty  rate for Sanofi’s
isatuximab anti-CD38 naked antibody compound to be reduced to low single digits because of
(1) competitor development of alternative  anti-CD38 antibody compounds,  and (2) the lack of
ImmunoGen patent rights covering isatuximab, since  our  ADC-related  patent rights do not pertain  to
the compound and our isatuximab -specific patent rights were assigned to Sanofi  under the  terms of the
applicable license.

We depend on our collaborative partners for the  determination of royalty payments.  We may not be
able to detect errors and payment calculations may  call for  retroactive adjustments.

The royalty payments we receive are determined  by  our collaborative partners based on their

reported net sales. Each collaborative  partner’s calculation of the royalty  payments is subject to and
dependent upon the adequacy and accuracy  of its  sales  and accounting  functions, and errors may occur
from time to time in the calculations  made by a collaborative partner. Our agreement with  Genentech
provides us the right to audit the calculations and  sales  data for the associated royalty  payments related
to sales of Kadcyla; however, such audits  may  occur many months following our recognition of the
royalty revenue, may require us to adjust  our royalty revenues in  later periods and generally require
audit-related cost on our part.

If our collaborative partners’ requirements for  clinical  materials to be manufactured by us are
significantly lower than we have estimated, our financial results  and  condition  could be  adversely
affected.

We  procure certain components of finished conjugate, including DM1,  DM4, and linker, on  behalf
of several of our collaborators. In order  to meet our commitments to our collaborative partners, we are
required to enter into agreements with third parties to produce  these components well in  advance  of
our  production of clinical materials on  behalf  of  our  collaborative partners. If our collaborative partners
do not require as much clinical material  as  we have  contracted  to  produce and we are unable to use

34

these materials for our own products,  we  may not be able to recover our  investment in  these
components and we may suffer losses. Collaborators have  discontinued development of  product
candidates in the past and in the periods  subsequent to these discontinuations, we had significantly
reduced demand for DM1 and DM4  which adversely  impacted  our financial  results.

In addition, we operate a conjugate manufacturing facility. A portion  of  the cost  of operating this
facility, including the cost of manufacturing personnel, is reimbursed by our  collaborators  based on  the
number of batches of preclinical and  clinical materials produced on  their behalf. If we produce  fewer
batches  of clinical materials for our collaborators, a  smaller amount  of the cost  of  operating the
conjugate manufacturing facility will  be  charged to our collaborative partners and our financial
condition could be adversely affected.

If our product requirements for clinical trials are significantly higher  than  we estimated, the inability
to procure additional antibody or fill/finish  services in  a timely manner could  impair our ability  to
initiate or advance our clinical trials.

We  rely  on third-party suppliers to manufacture antibodies  used  in our own proprietary

compounds. Due to the specific nature of  the antibody and availability of production capacity, there  is
significant lead time required by these  suppliers to provide us with  the needed materials. If our
antibody  requirements for clinical materials to be manufactured are  significantly  higher than  we
estimated, we may not be able to readily procure  additional antibody which would impair our ability to
advance  our clinical trials currently in  process or initiate  additional  trials.  We also rely  on third parties
to convert the bulk drug substance we  manufacture  into  filled and finished vials of drug product  for
clinical use. Unanticipated difficulties or delays in  the fill/finish process could impair our  ability to
advance  our clinical trials currently in  process or initiate  additional  trials.  There can  be  no assurance
that we will not have supply problems  that  could  delay or  stop our clinical trials or otherwise could
have a material adverse effect on our  business.

We currently rely on one third-party manufacturer with commercial production  experience  to produce
our cell-killing agents, DM1 and DM4.

We  rely  on a third-party supplier to manufacture one of the  materials used to make  ADC
compounds. Our cell-killing agents DM1  and  DM4, collectively DMx, are manufactured  from a
precursor, ansamitocin P3. We currently  use a single supplier, Societ´a Italiana Corticosteroidi S.r.l., that
converts ansamitocin P3 to DMx. Any delay or  interruption in our supply  of  DMx could lead  to  a delay
or interruption in our manufacturing  operations,  preclinical studies and clinical trials of our product
candidates and our collaborators’ product candidates, which could  negatively affect  our business.

We may be delayed or unable to establish the manufacturing capabilities necessary to develop  and
commercialize our and our collaborative  partners’ potential  products.

Currently, we have one conjugate manufacturing facility that  we use to manufacture conjugated

compounds for us and several of our collaborative  partners  for preclinical studies and early-stage
clinical testing. Several of our partners  have  contracted for separate, large-scale manufacturing  capacity
to make materials to support potential  future commercialization of their ADC compounds. We  do not
currently have the manufacturing capacity needed to make our product candidates for commercial sale.
In addition, our manufacturing capacity may be insufficient to complete all clinical trials contemplated
by us and our collaborative partners over time.  We  intend to rely in  part  on third-party contract
manufacturers to produce sufficiently  large quantities of drug materials  that are and  will be needed for
later-stage clinical trials and commercialization of our potential products. We  are currently in the
process of developing relationships with third-party manufacturers that we believe  will  be  necessary  to
continue the development of our product  candidates. Third-party manufacturers may  not  be  able to
meet our needs with respect to timing, quantity or quality of materials. If  we are  unable to contract  for

35

a sufficient supply of needed materials on  acceptable terms, or if we should encounter delays or
difficulties in our relationships with manufacturers, our clinical trials may  be  delayed, thereby delaying
the submission of product candidates  for regulatory approval  and the market introduction and
subsequent commercialization of our  potential products. Any such  delays may  lower our revenues  and
potential profitability.

We have one conjugate manufacturing  facility and  any prolonged and  significant disruption at that
facility could impair our ability to manufacture our and our collaborative partners’ product  candidates
for clinical testing.

Currently, in certain cases, we are contractually obligated to manufacture  Phase I and non-pivotal
Phase II clinical products for companies licensing  our ADC technology.  We manufacture this material,
as well as material for our own product  candidates, in  our conjugate manufacturing  facility.  We have
only one such manufacturing facility in  which we can  manufacture clinical products.  Our current
manufacturing facility contains highly specialized  equipment and utilizes complex  production  processes
developed over a number of years that  would be difficult, time-consuming and costly  to  duplicate.  Any
prolonged disruption in the operations  of  our manufacturing  facility would have a  significant negative
impact on our ability to manufacture  products for clinical testing on our  own and  would cause us to
seek additional third-party manufacturing contracts, thereby  increasing  our  development costs.  Even
though we carry business interruption  insurance policies, we  may suffer losses as a result of business
interruptions  that exceed the coverage available  or any losses which may be  excluded under  our
insurance policies. Certain events, such as natural disasters, fire, political disturbances, sabotage or
business accidents, which could impact  our current or future facilities, could have a  significant negative
impact on our operations by disrupting  our product  development efforts until  such time as we are able
to repair our facility or put in place third-party  contract manufacturers to  assume this  manufacturing
role.

Unfavorable pricing regulations, third-party reimbursement practices or healthcare  reform initiatives
applicable to our product candidates could limit our potential product revenue.

Antibody-based anticancer products are often much more costly to produce than traditional
chemotherapeutics and tend to have significantly higher prices. Factors that help justify  the price
include the high mortality associated with  many types  of  cancer and the need for  more and  better
treatment options.

Regulations governing drug pricing and reimbursement vary widely  from  country to country. Some

countries require approval of the sales price of a  drug before  it can be marketed. Some countries
restrict the physicians that can authorize the  use of more  expensive medications.  Some  countries
establish treatment guidelines to help  limit the  use of more  expensive  therapeutics and  the pool of
patients that receive them. In some countries, including  the U.S., third-party payers  frequently  seek
discounts from list prices and are increasingly challenging the  prices charged  for medical products.
Because our product candidates are  in  the development stage, we do not know the level of
reimbursement, if any, we will receive  for  any products that we are able to successfully develop. If  the
reimbursement for any of our product candidates is inadequate in light of our development and other
costs, our ability to achieve profitability would be affected.

We  believe that the efforts of governments and third-party  payors to contain or reduce the cost  of

healthcare will continue to affect the  business and financial condition of pharmaceutical and
biopharmaceutical companies. A number  of  legislative  and regulatory proposals to change the
healthcare system in the U.S. and other major  healthcare markets have  been proposed and  adopted in
recent years. For example, the U.S. Congress enacted a  limited prescription  drug benefit for Medicare
recipients as part of the Medicare Prescription Drug, Improvement  and  Modernization Act of 2003.
While the program established by this  statute may  increase demand for any products  that  we are  able

36

to successfully develop, if we participate in this program, our  prices will be  negotiated with drug
procurement organizations for Medicare  beneficiaries and are likely  to  be lower than prices we might
otherwise obtain. Non-Medicare third-party  drug procurement organizations  may also base the  price
they are willing to pay on the rate paid  by drug procurement organizations for  Medicare beneficiaries.
The PPACA will also require discounts under the Medicare drug benefit program and increased rebates
on drugs covered by Medicaid. In addition, the PPACA imposes an  annual fee, which  will  increase
annually, on sales by branded pharmaceutical manufacturers. The financial impact of these discounts,
increased rebates and fees and the other provisions of the PPACA on our  business  is unclear and there
can be no assurance that our business will not be materially  adversely affected by the PPACA. In
addition, ongoing initiatives in the U.S.  have  increased and will continue  to  increase pressure on  drug
pricing. The announcement or adoption  of any such initiative could have  an adverse effect on  potential
revenues from any product candidate that  we may successfully develop.

We may be unable to establish sales  and  marketing  capabilities  necessary  to successfully
commercialize our potential products.

We  currently have no direct sales or marketing capabilities. We may rely on  third  parties to market
and sell most of our primary product candidates or we may outlicense these products  prior to the time
when these capabilities are needed. If we  decide to market our potential products through a  direct
sales force, we would need either to  hire a sales force with  expertise in  pharmaceutical sales or to
contract with a third party to provide a sales force  which meets  our needs.  We may be unable to
establish marketing, sales and distribution capabilities necessary to commercialize and gain market
acceptance for our potential products and be competitive. In addition, co-promotion  or other marketing
arrangements with third parties to commercialize potential products could significantly limit the
revenues we derive from these potential  products, and these  third parties may fail to commercialize our
compounds successfully.

If our product candidates or those of  our  collaborative partners  do not gain market acceptance, our
business  will suffer.

Even if clinical trials demonstrate the safety and efficacy  of  our and  our collaborative partners’

product  candidates and the necessary  regulatory approvals are obtained, our and our collaborative
partners’ products may not gain market  acceptance among physicians, patients, healthcare  payors and
other members of the medical community. The degree of market acceptance of  any products that we  or
our  collaborative partners develop will depend on a number of factors, including:

(cid:129) their level of clinical efficacy and safety;

(cid:129) their advantage over alternative treatment  methods;

(cid:129) our/the marketer’s and our collaborative partners’ ability to gain acceptable  reimbursement and

the reimbursement policies of government and third-party  payors; and

(cid:129) the quality of the distribution capabilities of  the party(ies) responsible  to market and  distribute

the product(s).

37

Physicians may not prescribe any of our  future products until such time as clinical  data  or other
factors demonstrate the safety and efficacy  of those  products as compared to conventional drugs  and
other treatments. Even if the clinical  safety and efficacy of therapies using our products is  established,
physicians may elect not to recommend  the therapies for any number of other reasons,  including
whether the mode of administration of our  products is effective for certain conditions, and whether the
physicians are already using competing products  that satisfy their  treatment objectives. Physicians,
patients, third-party payors and the medical  community may not accept and use any  product candidates
that we, or our collaborative partners,  develop. If our products do  not  achieve significant  market
acceptance and use, we will not be able  to  recover  the significant  investment we have  made in
developing such products and our business will be severely harmed.

We may be unable to compete successfully.

The markets in which we compete are well established and  intensely competitive. We  may be
unable to compete successfully against our current and future competitors. Our failure to compete
successfully may result in lower volume sold, pricing  reductions, reduced gross  margins and failure to
achieve market acceptance for our potential products. Our  competitors include research institutions,
pharmaceutical companies and biotechnology  companies, such as  Pfizer, Seattle  Genetics, Roche,
Bristol-Myers Squibb and Takeda. Many of  these organizations have substantially more  experience  and
more capital, research and development, regulatory, manufacturing, human and other resources than
we do. As a result, they may:

(cid:129) develop products that are safer or  more effective  than  our product candidates;

(cid:129) obtain FDA and other regulatory approvals or reach the market with their products  more

rapidly than we can, reducing the potential sales of our product  candidates;

(cid:129) devote greater resources to market or sell their  products;

(cid:129) adapt more quickly to new technologies and scientific  advances;

(cid:129) initiate or withstand substantial price competition more  successfully than we can;

(cid:129) have greater success in recruiting skilled scientific workers from  the  limited pool of available

talent;

(cid:129) more effectively negotiate third-party licensing  and collaboration  arrangements;  and

(cid:129) take advantage of acquisitions or other opportunities  more readily than we  can.

A number of pharmaceutical and biotechnology companies are currently developing products
targeting the same types of cancer that we target, and some of our competitors’ products  have entered
clinical trials or already are commercially  available.

Our product candidates, if approved and  commercialized,  will also compete against

well-established, existing, therapeutic  products that are  currently reimbursed by government  healthcare
programs, private health insurers and  health maintenance organizations. In addition, if our product
candidates are approved and commercialized, we  may  face competition from biosimilars. The route to
market for biosimilars was established  with the  passage of the PPACA in March 2010. The PPACA
establishes a pathway for the FDA approval of  follow-on  biologics  and provides twelve years data
exclusivity for reference products and an additional six  months exclusivity period if pediatric studies are
conducted. In Europe, the European Medicines  Agency has issued guidelines  for approving products
through an abbreviated pathway, and  biosimilars  have been approved in Europe. If  a biosimilar  version
of one of our potential products were approved in the U.S. or Europe, it could have a negative effect
on sales and gross profits of the potential product and our financial  condition.

38

We  face and will continue to face intense competition from  other companies for collaborative
arrangements with pharmaceutical and  biotechnology companies, for  relationships with  academic and
research institutions and for licenses  to proprietary technology. In addition, we  anticipate that we will
face increased competition in the future  as  new companies enter our markets and as scientific
developments surrounding antibody-based  therapeutics for  cancer continue  to  accelerate. While we will
seek to expand our technological capabilities  to  remain  competitive,  research and  development by
others may render our technology or  product  candidates obsolete or noncompetitive or  result in
treatments or cures superior to any therapy  developed by us.

If we are unable to protect our intellectual property rights adequately, the value of our  technology and
our product candidates could be diminished.

Our success depends in part on obtaining,  maintaining  and enforcing our patents and other

proprietary rights and our ability to avoid  infringing the proprietary rights of others. Patent law  relating
to the scope of claims in the biotechnology field  in which we operate  is still  evolving,  is surrounded by
a great deal of uncertainty and involves  complex legal, scientific and factual questions. To date, no
consistent policy has emerged regarding the  breadth of claims allowed  in biotechnology  patents.
Accordingly, our pending patent applications may not result in  issued patents or in  patent  claims  as
broad as in the original applications.  Although we own numerous patents, the issuance of  a patent is
not conclusive as to its validity or enforceability. Through  litigation, a third party may  challenge the
validity or enforceability of a patent after its  issuance.

Patents and applications owned or licensed by us may become the subject of interference,
opposition, nullity, or other proceedings  in a  court or  patent office in the U.S. or in a  foreign
jurisdiction to determine validity, enforceability  or priority of invention,  which could result  in
substantial cost to us. An adverse decision  in such a  proceeding may result in our loss of rights  under a
patent or patent application. It is unclear  how much protection, if any, will  be  given to our patents if
we attempt to enforce them or if they  are  challenged  in court  or in  other  proceedings. A competitor
may successfully invalidate our patents  or a challenge  could result in  limitations of the  patents’
coverage. In addition, the cost of litigation or interference proceedings to uphold the validity of  patents
can be substantial. If we are unsuccessful  in these proceedings, third  parties may be able to use  our
patented technology without paying us  licensing  fees  or royalties.  Moreover, competitors may  infringe
our  patents or successfully avoid them through  design innovation.  To prevent  infringement or
unauthorized use, we may need to file infringement claims,  which are expensive  and time-consuming. In
an infringement proceeding, a court  may  decide that a patent of ours is not valid. Even if the  validity
of our patents were upheld, a court may  refuse  to  stop the other party from using the  technology at
issue on the ground that its activities are not  covered by our patents.

The Leahy-Smith America Invents Act was signed into law on  September 16, 2011,  and became

fully effective in March 2013. In general, the legislation attempts to address  issues  surrounding the
enforceability of patents and the increase in patent litigation by, among other things, moving  to  a first
inventor-to-file system, establishing new procedures for  challenging  patents and  establishing different
methods for invalidating patents. Governmental rule-making implementing the new statute  is evolving
and will continue to introduce new substantive rules  and procedures, particularly with regard to
post-grant proceedings such as  inter partes review and post-grant review. In due course,  the courts will
interpret various aspects of the law and related agency  rules  in ways that we  cannot predict, potentially
making it easier for competitors and  other interested parties to challenge our  patents, which, if
successful, could have a material adverse effect on  our business and prospects. In addition,  as the
United States Supreme Court has become  increasingly active in reviewing U.S. patent law in recent
years, and the extent to which their recent decisions  will affect our ability to enforce certain types of
claims under our U.S. patents or obtain  future patents in certain areas  is difficult to predict at this
time.

39

Policing unauthorized use of our intellectual property is  difficult,  and we may not be able to
prevent misappropriation of our proprietary  rights, particularly in countries where the laws may  not
protect such rights as fully as in the U.S.

In addition to our patent rights, we also rely on  unpatented technology, trade secrets, know-how

and confidential information. Third parties may  independently develop substantially equivalent
information and techniques or otherwise gain access to or disclose  our technology. We may not be able
to effectively protect our rights in unpatented technology,  trade secrets, know-how and  confidential
information. We require each of our  employees,  consultants  and corporate  partners  to  execute a
confidentiality agreement at the commencement of an  employment, consulting or collaborative
relationship with us. Further, we require that all employees enter into assignment of invention
agreements as a condition of employment. However, these agreements may not provide effective
protection of our information or, in the  event of unauthorized  use or  disclosure, they  may not provide
adequate remedies.

Any inability to license proprietary technologies or processes from third parties  which  we  use in
connection with the development and manufacture of our product candidates may impair our business.

Other companies,  universities and research institutions have or may obtain patents  that  could  limit

our  ability to use, manufacture, market or sell our  product candidates  or  impair  our  competitive
position. As a result, we would have  to  obtain licenses from  other parties before we  could  continue
using, manufacturing, marketing or selling  our potential  products.  Any  necessary licenses may  not  be
available on commercially acceptable terms, if at  all.  If we  do not obtain required  licenses,  we may not
be able to market our potential products at all or we may encounter significant delays in product
development while we redesign products or  methods that are found to infringe on  the patents held by
others.

We may incur substantial costs as a  result  of litigation or other proceedings relating to  patent and
other intellectual property rights held  by  third parties and  we  may be unable  to protect our rights to,
or to commercialize, our product candidates.

Patent litigation is very common in the biotechnology and  pharmaceutical industries. Third parties

may assert patent or other intellectual  property infringement claims  against  us with respect  to  our
technologies, products or other matters.  From time  to  time, we  have received correspondence  from
third parties alleging that we infringe  their intellectual property rights. Any claims that might be
brought against us alleging infringement of patents may cause us to incur significant expenses  and, if
successfully asserted against us, may cause us to pay  substantial damages and  limit our  ability to use the
intellectual property subject to these  claims.  Even if we were to prevail, any litigation would be costly
and time-consuming and could divert the  attention of our management and key personnel from our
business operations. Furthermore, as  a  result of a  patent  infringement suit,  we may be forced  to  stop or
delay developing, manufacturing or selling potential products  that incorporate the challenged
intellectual property unless we enter into  royalty  or license agreements. There may  be  third-party
patents, patent applications and other intellectual  property  relevant  to  our potential  products that may
block or  compete with our products  or processes.  In  addition, we sometimes undertake research and
development with respect to potential  products even  when we are aware of third-party patents  that  may
be relevant to our potential products, on the basis that  such patents may be challenged or  licensed by
us. If our subsequent challenge to such  patents were not to prevail,  we may not be able to
commercialize our potential products  after having already incurred significant  expenditures unless we
are able to license the intellectual property  on commercially  reasonable terms.  We may not be able to
obtain royalty or license agreements on  terms acceptable to us, if at all. Even  if we were able  to  obtain
licenses to such technology, some licenses may be non-exclusive, thereby giving our competitors access
to the same technologies licensed to  us.  Ultimately, we may be unable to  commercialize some  of our

40

potential products or may have to cease  some of our business operations, which could severely harm
our  business.

We use hazardous materials in our business, and any claims relating  to  improper  handling, storage or
disposal of these materials could harm  our business.

Our research and development and manufacturing activities  involve the controlled use of
hazardous materials, chemicals, biological  materials and  radioactive compounds.  We are subject  to
federal, state and local laws and regulations governing the  use, manufacture,  storage,  handling and
disposal of these materials and certain waste products. Although  we  believe  that  our  safety procedures
for handling and disposing of these materials comply with the standards  prescribed  by  applicable laws
and regulations, we cannot completely  eliminate  the risk of accidental contamination or  injury  from
these materials. In the event of such an accident,  we could be held liable for any  resulting damages,
and any liability could exceed our resources. We may be required to incur significant  costs to comply
with these laws in the future. Failure to comply with  these  laws could  result in fines  and the  revocation
of permits, which could prevent us from  conducting our business.

We face product liability risks and may  not be able to  obtain adequate insurance.

While we secure waivers from all participants in our clinical  trials, the use of our product
candidates during testing or after approval entails an  inherent risk of adverse effects, which could
expose us to product liability claims. Regardless of their merit or eventual  outcome, product liability
claims may result in:

(cid:129) decreased demand for our product;

(cid:129) injury to our reputation and significant negative media  attention;

(cid:129) withdrawal of clinical trial volunteers;

(cid:129) costs of litigation;

(cid:129) distraction of management; and

(cid:129) substantial monetary awards to plaintiffs.

We  may not have sufficient resources to satisfy any liability  resulting from these  claims. We
currently have product liability insurance  for products  which are  in clinical testing,  however, our
coverage may not  be adequate in scope  to protect us  in the event  of a successful  product liability claim.
Further, we may not be able to maintain our current insurance  or obtain general product liability
insurance on reasonable terms and at  an acceptable cost  if we or our collaborative partners begin
commercial production of our proposed product candidates. This insurance, even  if  we can obtain and
maintain it, may not be sufficient to provide us  with adequate coverage against potential liabilities.

We depend on our key personnel and we  must continue  to attract and  retain key employees and
consultants.

We  depend on our key scientific and management personnel. Our ability to pursue the

development of our current and future  product  candidates depends largely  on retaining the services of
our  existing personnel and hiring additional qualified scientific personnel to perform research and
development. We will also need to hire  personnel with expertise in clinical testing,  government
regulation, manufacturing, marketing  and finance.  Attracting and retaining qualified personnel will be
critical to our success. We may not be able to attract and retain personnel on  acceptable terms given
the competition for such personnel among  biotechnology, pharmaceutical and healthcare companies,
universities and non-profit research institutions. Failure  to retain our  existing key management and

41

scientific personnel or to attract additional  highly qualified personnel could delay the development of
our  product candidates and harm our  business.

Our stock price can fluctuate significantly and  results announced by us and  our collaborators  can
cause our stock price to decline.

Our stock price can fluctuate significantly due to business developments  announced by us and by

our  collaborators, or as a result of market trends and daily  trading  volume. The business developments
that could impact our stock price include disclosures  related to clinical findings with compounds that
make use of our ADC technology, new  collaborations and clinical advancement or  discontinuation  of
product  candidates that make use of  our ADC  technology. Our stock price  can also  fluctuate
significantly with the level of overall investment  interest  in small-cap biotechnology stocks.

Our operating results have fluctuated in the past and are likely to continue to do so in the  future.

Our revenue is unpredictable and may fluctuate due to the timing  of  non-recurring  licensing fees,
decisions of our collaborative partners  with  respect to our agreements with them,  reimbursement for
manufacturing services, the achievement  of  milestones and our receipt of  the  related milestone
payments under new and existing licensing and collaboration agreements. Revenue historically
recognized under our prior collaboration  agreements may not be an  indicator of revenue  from any
future collaboration. In addition, our expenses are unpredictable  and may  fluctuate from quarter to
quarter due to the timing of expenses,  which  may include obligations  to  manufacture  or supply product
or payments owed by us under licensing or collaboration  agreements. It is  possible  that  our quarterly
and/or annual operating results will not  meet the expectations of securities  analysts  or investors, causing
the market price of our common stock to decline. We believe  that quarter-to-quarter and year-to-year
comparisons of our operating results  are not good  indicators of our future performance and  should not
be relied upon to predict the future performance  of our stock price.

The potential sale  of additional shares  of our common stock may cause our stock price  to decline.

Pursuant to shelf registration statements  filed  with the Securities and Exchange Commission, in

fiscal 2012, we sold 6,250,000 shares  of  our common stock at  $16.00 per share  in a public offering
resulting in gross proceeds of $100 million; in fiscal 2011, we sold 7,800,000  shares of our common
stock at $12.00 per share in a public offering resulting in gross proceeds  of $93.6 million;  in fiscal 2010,
we sold 10,350,000 shares of our common  stock at  $8.00 per  share in a public offering  resulting in  gross
proceeds of $82.8 million; and in fiscal  2009, we sold 5,750,000 shares of our  common stock at  $7.00
per  share in a public offering resulting  in  gross proceeds of $40.3 million. The potential sale of
additional shares of our common stock  may  be  dilutive to our  shares outstanding and may cause our
stock price to decline.

We do not intend to pay cash dividends  on our common stock.

We  have not paid cash dividends since  our  inception and do not intend to  pay cash  dividends  in
the foreseeable future. Therefore, shareholders will have to rely on appreciation in  our stock  price, if
any, in order to achieve a gain on an investment.

42

A WARNING ABOUT FORWARD-LOOKING  STATEMENTS

This report includes forward-looking  statements  within the meaning  of the Private  Securities
Litigation Reform  Act of 1995. These statements relate to analyses and other information which  are
based on forecasts of future results and  estimates of amounts that are not yet  determinable. These
statements also relate to our future prospects,  developments and business  strategies.

These forward-looking statements are identified  by  their  use of terms  and  phrases,  such as
‘‘anticipate,’’ ‘‘believe,’’ ‘‘could,’’ ‘‘estimate,’’ ‘‘expect,’’  ‘‘intend,’’ ‘‘may,’’ ‘‘plan,’’ ‘‘predict,’’ ‘‘project,’’
‘‘will’’ and other similar terms and phrases, including references to assumptions.  These statements are
contained in the ‘‘Business,’’ ‘‘Risk Factors’’ and  ‘‘Management’s Discussion and Analysis of Financial
Condition and Results of Operations’’  sections,  as well  as other sections of this Annual Report  on
Form 10-K.

These forward-looking statements involve known and unknown risks, uncertainties  and other

factors that may cause actual results to be materially different from those contemplated by our  forward-
looking statements. These known and unknown risks,  uncertainties and other factors are described in
detail in the ‘‘Risk Factors’’ section and  in other sections of  this  Annual  Report on Form 10-K. We
disclaim any intention or obligation to  update or  revise any forward-looking  statements,  whether as a
result of new information, future events  or otherwise.

Item 1B. Unresolved Staff Comments

None.

Item 2. Properties

We  lease approximately 108,000 square  feet of laboratory and office  space in a  building located at
830 Winter Street, Waltham, MA. The  term of the 830 Winter  Street lease expires  on March  31, 2026,
with an option for us to extend the lease  for two additional five-year terms. We also  lease
approximately 43,850 square feet of space at 333 Providence  Highway, Norwood, MA, which serves  as
our  conjugate manufacturing facility and office space. The 333 Providence Highway lease expires on
June 30, 2018, with an option for us  to  extend the  lease for an additional five-year term. Due to space
requirements, in April 2013, we entered into  a lease agreement  for the  rental of 7,507 square feet of
office space at 100 River Ridge Drive,  Norwood, MA. The initial term  of the lease  is for five  years  and
two months commencing in July 2013 with an option for us to extend the lease for an additional
five-year  term. We entered into a sublease in December 2014 for this  space, effective January 2015
through the remaining initial term of the  lease.

Item 3. Legal Proceedings

From time to time we may be a party to various  legal proceedings arising in the ordinary course of

our  business. We are not currently subject to any material legal proceedings.

Item 3.1. Executive Officers of the Registrant

ImmunoGen’s executive officers are  appointed  by the  Board of Directors at  the first meeting of
the Board following the annual meeting  of shareholders or  at other Board meetings as appropriate, and
hold office until the first Board meeting following the next annual meeting of  shareholders and  until a
successor is chosen, subject to prior death, resignation or removal. Information regarding our executive
officers is presented below.

Daniel M. Junius, age 63, joined ImmunoGen in  2005, and has served as  our  President and  Chief

Executive Officer since 2009. Mr. Junius has  also served as  a  director  of ImmunoGen since 2008 and  is

43

a director of IDEXX Laboratories, Inc. Mr. Junius holds a  Masters of Management  from Northwestern
University’s Kellogg School of Management.

Richard J. Gregory, age 57, joined ImmunoGen in  January 2015, and has  served as our Executive

Vice President and Chief Scientific Officer since that date.  Prior to joining ImmunoGen, he spent
25 years at Genzyme Corporation, a  biotechnology company,  in roles of increasing responsibility,
including Senior Vice President and  Head of Research from 2003 until Genzyme’s acquisition by Sanofi
in 2011, and Head of Research and Development  for Genzyme from 2011 through 2014.  Dr. Gregory
holds a PhD from the University of Massachusetts, Amherst,  and completed his  post-doctoral work  at
the Worcester Foundation for Experimental Biology.

John M. Lambert,  PhD, age 64, joined ImmunoGen in 1987, and has served as  Executive Vice

President and Distinguished Research  Fellow since January 2015. Prior to that he served as  our
Executive Vice President and Chief Scientific  Officer from 2008  through 2014. Dr.  Lambert  holds a
PhD in Biochemistry from University of  Cambridge  in England, and completed his  postdoctoral work
at the University of California at Davis  and  at Glasgow  University in Scotland.

David B. Johnston, age 60, joined ImmunoGen in  2013, and  has served as our  Executive Vice
President and Chief Financial Officer  since that  date. Prior  to  joining ImmunoGen,  Mr.  Johnston
served as Chief Financial Officer of AVEO Pharmaceuticals, Inc., a biotechnology company, from 2007
to 2013. Mr. Johnston holds a Master of  Business Administration from the University  of Michigan.

Charles Q. Morris, MB, ChB, MRCP (UK),  age  50, joined ImmunoGen in November  2012, and
has served as our Executive Vice President and Chief Development Officer since that date. Prior to
joining ImmunoGen, he served as Executive  Vice President and Chief Medical Officer  of Allos
Therapeutics, Inc., a biotechnology company,  from 2010 until its acquisition in  2012. Prior  to  that  he
served as Vice President, Worldwide  Clinical Research, at Cephalon,  Inc., a biotechnology company,
from 2008 to 2010. Dr. Morris holds  his  medical  degrees  from Sheffield  University Medical School and
is a member of the Royal College of Physicians of London.

Sandra Poole, age 51, joined ImmunoGen in September 2014, and has served as our  Executive

Vice President of Technical Operations  since July  1, 2015. Prior to that she served  as our Senior Vice
President, Technical Operations, from her  date of hire through June  2015. Prior to joining  ImmunoGen,
she  spent 15 years at Genzyme Corporation, a biotechnology company, and  its subsidiaries in roles  of
increasing responsibility, including as  Senior Vice President overseeing  various technical operations
within Genzyme from 2009 to 2013, and as  Senior  Vice President,  Biologics Manufacturing from 2013
to September 2014.

Craig Barrows, age 60, joined ImmunoGen  in 2007, and has  served as our Vice  President,  General

Counsel and Secretary since that date.

Ellie Harrison, age 60, joined ImmunoGen  in February 2014, and has served  as our Vice President
and Chief Human Resources Officer since that date. Prior to joining  ImmunoGen, she served as Senior
Vice President of Human Resources  of  Blue Cross and  Blue Shield of Rhode  Island, a healthcare
provider, from 2013 to February 2014.  Prior to that she served as a Managing Director and Senior
Human Resources Advisor to the global consumer banking organization  of Citigroup, a financial
institution, from 2009 to 2012.

Peter J. Williams, age 61, joined ImmunoGen  in August 2009,  and has  served  as our Vice

President, Business Development since that date.

Item 4. Mine Safety Disclosures

None.

44

PART II

Item 5. Market for Registrant’s Common Equity, Related Stockholder Matters and Issuer Purchases of

Equity Securities

Market Price of Our Common Stock and  Related  Stockholder Matters

Our common stock is quoted on the  NASDAQ Global Select Market under the symbol ‘‘IMGN.’’
The table below sets forth the high and low closing price per share of our common  stock as reported
by NASDAQ:

Fiscal Year 2015

High

Low

Fiscal Year 2014

High

Low

First  Quarter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Second Quarter . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Third Quarter . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fourth Quarter . . . . . . . . . . . . . . . . . . . . . . . . . . . .

$12.74
$11.00
$ 9.55
$15.88

$10.28
$ 5.34
$ 5.85
$ 7.91

$20.25
$18.19
$17.80
$15.59

$15.07
$12.55
$14.20
$10.69

As of August 20, 2015, the closing price per share of our common stock  was  $12.47, as reported  by

NASDAQ, and we had approximately 470 holders of record of  our common stock.

We  have not paid any cash dividends on our  common stock since our  inception and  do  not  intend

to pay any cash dividends in the foreseeable future.

Equity Compensation Plan Information (in thousands)

Plan category

Equity compensation plans approved

by security holders(1) . . . . . . . . . . . .

Equity compensation plans not

approved by security holders . . . . . .

Total . . . . . . . . . . . . . . . . . . . . . . . . .

(a)

(b)

(c)

Number of securities to
be issued upon exercise
of outstanding options,
warrants and rights

Weighted-average
exercise price of
outstanding  options,
warrants and rights

Number of securities
remaining available for
future issuance under
equity compensation plans
(excluding securities
reflected in column (a))

9,689

—

9,689

$12.49

—

$12.49

6,232

—

6,232

(1) These plans consist of the Restated Stock  Option  Plan  and  the 2006  Employee,  Director and

Consultant Equity Incentive Plan.

Recent  Sales of Unregistered Securities; Uses of Proceeds  from Registered  Securities;  Issuer
Repurchases of Equity Securities

None.

Item 6. Selected Financial Data

The following table (in thousands, except per share  data) sets  forth our  consolidated financial data
for each  of our five fiscal years through our fiscal  year  ended June  30, 2015. The  information set  forth
below should be read in conjunction  with ‘‘Management’s Discussion and Analysis of Financial

45

Condition and Results of Operations’’  and  the consolidated  financial  statements and  related notes
included elsewhere in this Annual Report  on Form 10-K.

Year Ended June 30,

2015

2014

2013

2012

2011

Consolidated Statement of Operations  Data:
Total revenues . . . . . . . . . . . . . . . . . . . . . . . .
Total operating expenses . . . . . . . . . . . . . . . . .
Non-cash interest expense on liability related

to sale of future royalty . . . . . . . . . . . . . . . .
Other (expense) income, net . . . . . . . . . . . . . .

$ 85,541
139,996

$ 59,896
131,427

$ 35,535
108,544

$ 16,357
89,614

$ 19,305
79,493

5,437
(847)

—
167

—
198

—
(62)

—
1,914

Net loss . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

$ (60,739) $ (71,364) $ (72,811) $ (73,319) $ (58,274)

Basic and diluted net loss per common  share . .

$

(0.71) $

(0.83) $

(0.87) $

(0.95) $

(0.85)

Basic and diluted weighted average common

shares outstanding . . . . . . . . . . . . . . . . . . .

86,038

85,481

84,063

76,814

68,919

Consolidated Balance Sheet Data:
Cash, cash equivalents and marketable

securities . . . . . . . . . . . . . . . . . . . . . . . . . .
Total assets . . . . . . . . . . . . . . . . . . . . . . . . . .
Shareholders’ equity . . . . . . . . . . . . . . . . . . . .

$278,109
313,823
35,104

$142,261
165,318
75,699

$194,960
213,596
121,847

$160,938
180,308
83,890

$191,206
217,641
139,969

46

Item 7. Management’s Discussion and Analysis of Financial Condition and Results of Operations

Overview

Since our inception, we have been principally  engaged  in the development of  novel, antibody-drug

conjugates, or ADCs, for the treatment of cancer using our  expertise in cancer biology, monoclonal
antibodies, highly potent cytotoxic, or  cell-killing, agents,  and the design of linkers that enable  these
agents to remain stably attached to the  antibodies while in the blood  stream  and released in  their  fully
active  form after delivery to a cancer cell. An anticancer compound  made  using  our  ADC technology
consists of a monoclonal antibody that binds  specifically  to an antigen target found  on the surface of
cancer cells with one of our proprietary cell-killing agents attached to the antibody using one of our
engineered linkers. Its antibody component enables an  ADC  compound to bind specifically to cancer
cells that express its target antigen, the  highly potent cytotoxic agent serves to kill the cancer cell, and
the engineered linker controls the release  and activation  of the cytotoxic agent inside  the cancer cell.
With some ADC compounds, the antibody component also has anticancer activity of its own. Our ADC
technology is designed to enable the  creation of highly effective, well-tolerated anticancer  products. All
of the ADC compounds currently in  clinical testing  contain either  DM1 or DM4 as the  cytotoxic  agent.
Both DM1 and DM4, collectively DMx, are our proprietary derivatives of a  cytotoxic  agent  called
maytansine. We also have developed agents  we call IGNs, one of  which, DGN462,  is used in  our
preclinical compound IMGN779.

We  use our proprietary ADC technology in conjunction with  our in-house antibody expertise to

develop our own anticancer product candidates.  We also enter into  agreements that enable companies
to use our ADC technology to develop and  commercialize product  candidates to specified  targets.
Under the terms of our agreements, we are generally entitled  to  upfront fees, milestone  payments, and
royalties on any commercial product  sales. In addition, under  certain agreements we are compensated
for research and development activities  performed at  our  collaborative partner’s request at  negotiated
prices which are generally consistent  with what other third parties would charge.  We are compensated
to manufacture preclinical and clinical  materials and deliver cytotoxic  agent material at  negotiated
prices which are generally consistent  with what other third parties would charge.  Currently,  our
partners include Amgen, Bayer HealthCare, Biotest, Lilly,  Novartis, Roche, Sanofi and  Takeda.  We also
have a research agreement with CytomX  Therapeutics that allows each company to develop
probody-drug conjugates against a specified number  of  cancer targets using CytomX’s Probody(cid:5)
antibody  masking technology with our  payload agents and engineered linkers.  We expect  that
substantially all of our revenue for the  foreseeable future will result from payments under  our
collaborative arrangements. Details for some of our major  and recent collaborative agreements  can be
found in this Form 10-K under Item 1. Business.

To date, we have not generated revenues  from commercial sales of internal products and  we expect

to incur significant operating losses for  the  foreseeable future. As of June 30, 2015,  we had
approximately $278.1 million in cash  and cash equivalents compared  to  $142.3 million as of June 30,
2014.

We  anticipate that future cash expenditures will  be  partially offset by collaboration-derived
proceeds, including milestone payments  and  upfront fees. Accordingly, period-to-period cash  balances
may fluctuate dramatically based upon  the timing  of  receipt of the proceeds. We believe that our
established collaborative agreements, while subject to specified  milestone achievements,  will provide
funding to assist us in meeting obligations  under our collaborative agreements while also assisting in
providing funding for the development of internal product  candidates and technologies.  However, we
can give no assurances that such collaborative  agreement funding will, in  fact, be realized in the  time
frames we expect, or at all. Should we  or  our  partners  not  meet some  or  all  of the terms  and
conditions of our various collaboration agreements, we may be required  to secure alternative financing
arrangements, find additional partners and/or  defer  or limit some or all of our research, development

47

and/or clinical projects. However, we  cannot provide assurance that  any such opportunities  presented  by
additional partners or alternative financing arrangements  will be entirely available to us, if at  all.

Critical Accounting Policies

We  prepare our consolidated financial  statements  in accordance with accounting principles

generally accepted in the U.S. The preparation of  these financial statements  requires us to make
estimates and judgments that affect the reported amounts of assets, liabilities, revenues  and expenses
and related disclosure of contingent assets and liabilities. On  an on-going  basis, we evaluate our
estimates, including those related to our  collaborative agreements, clinical  trial  accruals, inventory and
stock-based compensation. We base our  estimates on historical  experience and various  other
assumptions that we believe to be reasonable  under the  circumstances.  Actual results  may differ from
these estimates.

We  believe the following critical accounting policies reflect our more significant judgments  and

estimates used in the preparation of our consolidated  financial  statements.

Revenue Recognition

We  enter into licensing and development agreements with collaborative partners for  the

development of monoclonal antibody-based  anticancer therapeutics.  The  terms of these agreements
contain multiple deliverables which may include (i) licenses, or options to  obtain  licenses, to our ADC
technology, (ii) rights to future technological  improvements, (iii)  research activities  to  be  performed on
behalf of the collaborative partner, (iv)  delivery of cytotoxic agents and (v) the  manufacture of
preclinical or clinical materials for the collaborative  partner. Payments  to  us under these agreements
may include upfront fees, option fees,  exercise fees, payments  for research activities, payments for the
manufacture of preclinical or clinical  materials, payments  based upon  the achievement of  certain
milestones and royalties on product sales.  We  follow  the provisions of  the Financial Accounting
Standards Board (FASB) Accounting  Standards Codification (ASC)  Topic  605-25, ‘‘Revenue
Recognition—Multiple-Element Arrangements,’’ and ASC  Topic 605-28, ‘‘Revenue Recognition—
Milestone Method,’’ in accounting for these agreements. In  order to account for  these agreements, we
must identify the deliverables included  within the agreement and evaluate which deliverables represent
separate units of accounting based on  whether certain criteria are met, including whether the delivered
element has stand-alone value to the  collaborator. The consideration  received  is allocated among the
separate units of accounting, and the  applicable revenue recognition criteria are applied to each of  the
separate units.

At June  30, 2015, we had the following two types of agreements with the  parties identified below:

(cid:129) Development and commercialization licenses,  which provide  the party with  the right to use our
ADC technology and/or certain other intellectual property to develop compounds  to  a specified
antigen target:

Amgen (four exclusive single-target licenses*)

Bayer HealthCare (one exclusive single-target  license)

Biotest (one exclusive single-target license)

Lilly (three exclusive single-target licenses)

Novartis (five exclusive single-target licenses  and  one  license  to  two related targets:  one  target
on an exclusive basis and the second target  on a  non-exclusive  basis)

Roche, through its Genentech unit (five exclusive single-target licenses)

Sanofi (one exclusive single-target license and one exclusive license to multiple individual
targets)

* Amgen has sublicensed one of its exclusive single-target licenses to Oxford BioTherapeutics Ltd.

48

(cid:129) Research license/option agreement  for a defined period  of  time  to  secure  development and
commercialization licenses to use our  ADC technology to develop anticancer compounds to
specified targets on established terms (referred to herein as right-to-test agreements):

Sanofi

CytomX

Takeda

There are no performance, cancellation,  termination  or refund provisions in any of the

arrangements that contain material financial  consequences  to  us.

Development and Commercialization Licenses

The deliverables under a development and commercialization  license agreement  generally  include

the exclusive license to our ADC technology with respect to a  specified antigen target, and may also
include deliverables related to rights  to  future technological improvements, research activities to be
performed on behalf of the collaborative  partner and the manufacture of preclinical or clinical
materials for the collaborative partner.

Generally, development and commercialization licenses contain non-refundable terms  for payments

and, depending on the terms of the agreement, provide  that we will  (i) at the collaborator’s request,
provide research services at negotiated  prices which  are generally consistent  with what  other  third
parties would charge, (ii) at the collaborator’s request, manufacture  and provide to it preclinical and
clinical materials or deliver cytotoxic  agents at  negotiated prices  which are generally consistent  with
what other third parties would charge, (iii)  earn payments upon the  achievement of certain milestones
and (iv) earn royalty payments, generally until  the later  of the last applicable  patent  expiration or  10 to
12 years after product launch. In the case of Kadcyla, however, the minimum royalty term  is 10  years
and the maximum royalty term is 12  years  on a  country-by-country basis,  regardless of  patent
protection. Royalty rates may vary over the royalty  term depending  on our intellectual property rights
and/or the presence of comparable competing products. We may  provide technical  assistance and share
any technology improvements with our  collaborators during the  term of the  collaboration  agreements.
We  do not directly control when or whether any collaborator will  request  research  or manufacturing
services, achieve milestones or become liable for royalty payments. As  a  result, we cannot predict  when
or if we will recognize revenues in connection  with any of the foregoing.

In determining the units of accounting, management evaluates  whether  the license has stand-alone

value from the undelivered elements  to  the collaborative  partner based on  the consideration of the
relevant facts and circumstances for each  arrangement.  Factors considered in  this  determination include
the research capabilities of the partner  and the  availability of ADC technology research expertise  in the
general marketplace. If we conclude that  the license  has stand-alone value and therefore will be
accounted for as a separate unit of accounting, we then determine the estimated selling prices  of the
license and all other units of accounting based on  market  conditions, similar arrangements entered into
by third parties, and entity-specific factors such as the  terms of our previous  collaborative  agreements,
recent preclinical and clinical testing  results of therapeutic products that use our ADC  technology, our
pricing practices and pricing objectives, the  likelihood that technological improvements will be made,
and, if made, will be used by our collaborators and  the nature  of the research services to be performed
on behalf of our collaborators and market  rates  for similar services.

Upfront payments on development and commercialization licenses are deferred if  facts and
circumstances dictate that the license does not have stand-alone value.  Prior to the adoption of
Accounting Standards Update (ASU) No. 2009-13,  ‘‘Revenue Arrangements  with Multiple
Deliverables’’ on July 1, 2010, we determined that our licenses  lacked  stand-alone value and were
combined with other elements of the  arrangement  and  any amounts  associated  with the license were

49

deferred and amortized over a certain  period, which we  refer to as our period of substantial
involvement. The determination of the  length of the period over which to defer revenue  is subject  to
judgment and estimation and can have an  impact on the  amount  of revenue  recognized in  a given
period. Historically our involvement with the development of a collaborator’s product  candidate has
been significant at  the early stages of  development, and lessens as it  progresses  into  clinical trials.  Also,
as a drug candidate gets closer to commencing pivotal testing  our collaborators  have sought  an
alternative site to manufacture their products, as our facility does not produce  pivotal or  commercial
drug product. Accordingly, we generally estimate  this period of substantial involvement to begin at the
inception of the collaboration agreement  and conclude  at the  end of non-pivotal Phase  II testing.  We
believe this period of substantial involvement is, depending on the nature of the license, on  average six
and one-half years. Quarterly, we reassess our periods of substantial involvement over which we
amortize our upfront license fees and make  adjustments  as appropriate. In the event  a collaborator
elects to discontinue development of a specific product candidate under a development  and
commercialization license, but retains  its  right  to  use our technology to develop an  alternative  product
candidate to the same target or a target substitute, we would  cease amortization of any remaining
portion of the upfront fee until there  is  substantial  preclinical activity  on another product candidate
and its remaining period of substantial involvement can be estimated. In the event  that  a development
and commercialization license were to be terminated, we  would recognize as revenue any portion  of  the
upfront fee that had not previously been  recorded as revenue,  but was classified  as deferred  revenue, at
the date of such termination.

Subsequent to the  adoption of ASU No. 2009-13, we  determined that our research licenses lack

stand-alone value and are considered for  aggregation with the  other  elements  of  the arrangement and
accounted for as one unit of accounting.

Upfront payments on development and commercialization licenses may be recognized  upon

delivery of the license if facts and circumstances dictate that  the  license  has stand-alone value from the
undelivered elements, which generally include rights to future  technological improvements, research
services, delivery of cytotoxic agents and the  manufacture of preclinical and  clinical materials.

We  recognize revenue related to research services that represent separate units of  accounting as

they are performed, as long as there is persuasive evidence of an arrangement, the fee is  fixed  or
determinable, and collection of the related  receivable is probable. We  recognize  revenue related to the
rights to future technological improvements  over the estimated term of the applicable license.

We  may also provide cytotoxic agents to our collaborators or produce preclinical  and clinical

materials for them at negotiated prices  which are generally consistent with  what other third parties
would charge. We recognize revenue on cytotoxic agents and  on preclinical and clinical materials when
the materials have passed all quality testing  required for collaborator acceptance and title  and risk of
loss have transferred to the collaborator.  Arrangement consideration  allocated  to  the manufacture of
preclinical and clinical materials in a multiple-deliverable arrangement is  below our full  cost, and our
full cost is not expected to ever be below our contract selling  prices for  our existing collaborations.
During  the fiscal years ended June 30, 2015, 2014 and 2013, the difference between our full  cost to
manufacture preclinical and clinical materials on behalf of  our collaborators as compared to total
amounts received from collaborators  for the manufacture  of  preclinical and clinical  materials was
$9.2 million, $2.3 million, and $755,000,  respectively. The majority of  our  costs to produce these
preclinical and clinical materials are  fixed  and then allocated to each batch  based on  the number  of
batches  produced during the period. Therefore, our costs to produce these materials are  significantly
impacted by the number of batches produced during the period. The volume  of  preclinical and clinical
materials we produce is directly related  to  the  number of  clinical  trials  we and our collaborators are
preparing for or currently have underway,  the speed of enrollment  in those  trials, the dosage schedule
of each clinical trial and the time period  such trials last. Accordingly,  the volume of preclinical and

50

clinical materials produced, and therefore our per-batch costs to manufacture these preclinical  and
clinical materials, may vary significantly from period to period.

We  may also produce research material  for  potential  collaborators under material transfer
agreements. Additionally, we perform  research  activities, including developing antibody specific
conjugation processes, on behalf of our collaborators  and potential  collaborators during the  early
evaluation and preclinical testing stages  of drug  development. We record amounts received for  research
materials produced or services performed  as a component of research and development  support
revenue. We also develop conjugation processes for materials for later stage testing and
commercialization for certain collaborators. We are  compensated at negotiated rates and  may receive
milestone payments for developing these  processes which are recorded as  a component of research and
development support revenue.

Our development and commercialization license  agreements  have milestone  payments which for

reporting purposes are aggregated into  three categories: (i)  development  milestones, (ii) regulatory
milestones, and (iii) sales milestones.  Development milestones are typically payable when  a product
candidate initiates or advances into different clinical trial phases. Regulatory milestones are typically
payable upon submission for marketing approval with the FDA or  other countries’ regulatory
authorities or on receipt of actual marketing approvals for the  compound or for additional indications.
Sales milestones are typically payable when annual sales  reach  certain levels.

At the inception of each agreement that includes  milestone payments, we evaluate whether each

milestone is substantive and at risk to both parties on the basis  of the contingent  nature of the
milestone. This evaluation includes an assessment of  whether (a) the  consideration is commensurate
with either (1) the entity’s performance  to  achieve the milestone,  or (2) the enhancement of the value
of the delivered item(s) as a result of  a specific  outcome  resulting from the entity’s performance  to
achieve the milestone, (b) the consideration relates solely  to past performance  and (c) the
consideration is reasonable relative to all  of  the deliverables  and payment  terms within  the
arrangement. We evaluate factors such  as  the scientific, regulatory, commercial and  other risks  that
must be overcome to achieve the respective milestone, the level of effort and investment required to
achieve the respective milestone and  whether the milestone  consideration is reasonable  relative to all
deliverables and payment terms in the  arrangement in making this assessment.

Non-refundable development and regulatory milestones  that are expected to be achieved as a

result of our efforts during the period  of substantial  involvement are considered  substantive  and are
recognized as revenue upon the achievement of the  milestone, assuming  all  other  revenue recognition
criteria are met. Milestones that are not considered substantive because we do not contribute effort to
the achievement of such milestones are generally  achieved after the period  of substantial  involvement
and are recognized as revenue upon  achievement of the  milestone, as there  are no  undelivered
elements remaining and no continuing performance  obligations,  assuming all other  revenue recognition
criteria are met.

Under our development and commercialization license  agreements, we receive royalty  payments

based upon our licensees’ net sales of covered products.  Generally, under  these  agreements we  are to
receive royalty reports and payments  from  our  licensees approximately one quarter in arrears, that is,
generally in the second month of the quarter  after the licensee has sold the royalty  bearing product or
products. We recognize royalty revenues  when we can reliably estimate such  amounts  and collectability
is reasonably assured. As such, we generally recognize royalty  revenues  in the quarter reported to us by
our  licensees, or one quarter following the  quarter in which sales by  our licensees occurred.

Right-to-Test Agreements

Our right-to-test agreements provide collaborators the right to (a) test our ADC technology for  a

defined period of time through a research, or right-to-test, license,  (b) take  options, for a defined

51

period of time, to specified targets and  (c) upon  exercise  of  those options, secure or  ‘‘take’’ licenses to
develop and commercialize products  for the specified  targets on  established terms.  Under these
agreements, fees may be due to us (i)  at  the inception of the arrangement (referred to as ‘‘upfront’’
fees or payments), (ii) upon taking an  option with respect to a  specific target (referred to as option
fees or payments earned, if any, when the  option is ‘‘taken’’), (iii) upon the exercise of a  previously
taken option to acquire a development and commercialization  license(s)  (referred to as exercise  fees or
payments earned, if any, when the development  and  commercialization license  is ‘‘taken’’),  or (iv) some
combination of all of these fees.

The accounting for right-to-test agreements is  dependent on the nature  of the option granted to

the collaborative partner. Options are considered  substantive if,  at the  inception of a right-to-test
agreement, we are at risk as to whether  the  collaborative  partner will  choose  to  exercise  the options to
secure development and commercialization licenses. Factors  that are considered in  evaluating  whether
options are substantive include the overall  objective  of  the arrangement,  the benefit the collaborator
might obtain from the agreement without  exercising the  options,  the  cost  to exercise the options
relative to the total upfront consideration,  and the  additional  financial commitments or  economic
penalties imposed on the collaborator  as  a result of  exercising the options.

For right-to-test agreements where the options to secure development and commercialization
licenses to our ADC technology are considered substantive,  we do not consider the development  and
commercialization licenses to be a deliverable at the  inception of the agreement. For  those right-to-test
agreements entered into prior to the  adoption of  ASU No. 2009-13 where the options to secure a
development and commercialization license are considered substantive, we have deferred  the upfront
payments received and recognize this revenue over the  period during which the collaborator could elect
to take options for development and commercialization licenses.  These periods are specific to each
collaboration agreement. If a collaborator takes  an option to acquire a  development and
commercialization license under these agreements,  any  substantive option fee is  deferred and
recognized over the life of the option,  generally 12 to 18 months. If  a  collaborator  exercises an option
and takes a development and commercialization license to a specific  target, we  attribute the exercise
fee to the development and commercialization license. Upon exercise of  an  option to acquire a
development and commercialization license, we  would also attribute any remaining  deferred option fee
to the development and commercialization license and apply  the  multiple-element revenue recognition
criteria to the development and commercialization license and  any other deliverables to determine the
appropriate revenue recognition, which will be consistent with our  accounting policy for upfront
payments on single-target licenses. In  the event  a right-to-test  agreement were to be terminated,  we
would recognize as revenue any portion  of  the upfront fee  that had not previously been  recorded as
revenue, but was classified as deferred  revenue, at  the date  of  such termination. None of  our
right-to-test agreements entered into subsequent  to  the adoption of ASU No. 2009-13 has been
determined to contain substantive options.

For right-to-test agreements where the options to secure development and commercialization
licenses to our ADC technology are not  considered substantive,  we consider  the development and
commercialization license to be a deliverable  at the inception of the agreement  and apply the multiple-
element revenue recognition criteria to  determine  the appropriate  revenue  recognition. None  of our
right-to-test agreements entered into prior to the adoption of  ASU No. 2009-13  has been determined to
contain non-substantive options.

We  do not directly control when or if  any collaborator will exercise its options for development
and commercialization licenses. As a  result, we  cannot predict when or if we will  recognize revenues  in
connection with any of the foregoing.

52

Inventory

We  review our estimates of the net realizable value of our inventory  at each reporting  period. Our
estimate of the net realizable value of our  inventory  is subject  to  judgment and estimation. The actual
net realizable value of our inventory  could vary significantly  from  our estimates. We  consider quantities
of raw materials in excess of twelve-month projected usage  that are not supported  by  firm,  fixed
collaborator orders and projections at the  time of  the assessment to be excess. During fiscal years 2015,
2014 and 2013, we obtained additional quantities of DMx  from our supplier which amounted to more
material than would be required by our collaborators over  the next twelve months and as a result, we
recorded  $1.0 million, $364,000 and $798,000,  respectively, of charges  to  research and development
expense related to raw material inventory identified as excess. Our collaborators’ estimates of their
clinical material requirements are based  upon expectations of their clinical trials, including the timing,
size, dosing schedule and the maximum tolerated dose  likely to be reached for the compound  being
evaluated. Our collaborators’ actual requirements  for clinical materials may  vary  significantly  from their
projections. Significant differences between our collaborators’ actual manufacturing orders and their
projections could result in our actual  twelve- month usage of raw materials varying significantly from
our  estimated usage at an earlier reporting period. Such differences and/or  reductions in  collaborators’
projections could indicate that we have  excess raw material inventory and we would then evaluate the
need to record write-downs, which would be included as charges to research and  development expense.

Stock-based Compensation

As of June 30, 2015, we are authorized to grant future awards under one share-based

compensation plan, which is the ImmunoGen, Inc. 2006  Employee,  Director and Consultant Equity
Incentive Plan. The stock-based awards are accounted  for under ASC Topic 718, ‘‘Compensation—
Stock Compensation,’’ pursuant to which  the estimated grant date fair value of awards is  charged to the
statement of operations over the requisite  service  period, which is the  vesting period. Such amounts
have been reduced by our estimate of forfeitures for unvested awards.

The fair value of each stock option is estimated on  the date  of grant using the  Black-Scholes
option-pricing model. Expected volatility  is based exclusively on  historical volatility data of  our stock.
The expected term of stock options granted  is based exclusively  on historical data and represents the
period of time that stock options granted are expected to be outstanding.  The  expected term is
calculated for and applied to one group of stock  options  as  we  do not  expect substantially  different
exercise or post-vesting termination behavior amongst our employee population.  The  risk-free rate of
the stock options is based on the U.S. Treasury rate in  effect at the time  of  grant for  the expected  term
of the stock options. Estimated forfeitures are  based on  historical data  as well as  current trends.  Stock
compensation cost incurred during the years ended  June 30, 2015, 2014  and 2013  was $15.3 million,
$15.6 million and $12.4 million, respectively.

Future stock-based compensation may  significantly  differ based on changes in  the fair value of our

common stock and our estimates of expected volatility and the other relevant assumptions.

Results of Operations

Revenues

Our total revenues for the year ended  June  30, 2015 were $85.5  million compared with

$59.9 million and $35.5 million for the  years ended June 30,  2014 and 2013, respectively. The $25.6 and
$24.4 million increases in revenues in  fiscal year 2015  and  fiscal  2014, respectively,  are attributable to
an increase in license and milestone  fees,  royalty revenue, non-cash  royalty revenue  and clinical
materials revenue, partially offset by  a decrease  in research and development support  revenue, all of
which  are discussed below.

53

Revenue from license and milestone  fees  for  the year  ended June 30, 2015  increased  approximately
$18.3 million to $57.8 million from $39.5 million  in the year ended  June 30, 2014. Revenue  from license
and milestone fees for the year ended  June 30,  2013 was $24.2 million. Included  in license  and
milestone fees for the year ended June 30,  2015 is  $15.6 million  of  license  revenue earned  upon the
execution of two development and commercialization licenses by Lilly, $25.7 million  of license  revenue
earned upon the execution of three development and commercialization  licenses by Novartis,  two
$5 million development milestones achieved under our collaboration agreement  with Novartis and
$4 million in development milestones  achieved under our collaboration  agreement with Sanofi. Also,
during the current year, we made a change  in estimate  to  our period of substantial involvement as it
relates to an exclusive license with Sanofi which  resulted in  an increase  to license and milestone fees of
$1.5 million for the current year compared to amounts that would have been  recognized pursuant to
the Company’s previous estimate. Additionally, during the current period, Janssen Biotech terminated
its  exclusive development and commercialization license  with us,  and as a result, we recognized  the
remaining $241,000 of the $1 million  upfront fee received upon  execution of the license which had
been previously deferred. Included in  license  and  milestone fees for the year ended June 30,  2014 is
$7.8 million of license revenue earned upon  the execution of a development  and commercialization
license by Lilly, two $5 million regulatory  milestones achieved  under our collaboration agreement  with
Roche, $18.2 million of license revenue earned upon the execution of two development  and
commercialization licenses and a one-year extension  of the original  term of the multi-target agreement
by Novartis, and $2.2 million of revenue from Amgen  related  to  a  modification  of an existing
arrangement. Included in license and  milestone fees for the  year ended June  30, 2013 was  a
$10.5 million regulatory milestone achieved  under our collaboration  agreement with Roche, a  $500,000
development milestone achieved under  our collaboration agreement with Sanofi and $11.1  million of
license revenue earned upon the execution  of  a development and commercialization license by
Novartis. The amount of license and milestone fees we earn  is directly related  to  the number  of our
collaborators, the collaborators’ advancement of  the product  candidates, and  the overall  success in  the
clinical trials of the product candidates.  As  such, the amount of license  and milestone  fees  may vary
widely from quarter to quarter and year  to year. Total revenue recognized from license and  milestone
fees from each of our collaborative partners in the years ended June 30,  2015, 2014 and 2013 is
included in the following table (in thousands):

License and Milestone Fees

Collaborative Partner:

$

Amgen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Bayer HealthCare . . . . . . . . . . . . . . . . . . . . . . . . .
Biotest
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Janssen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Lilly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Novartis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Roche . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Sanofi . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Year Ended June 30,

2015

2014

2013

17
—
25
241
15,644
35,915

$ 2,351
—
25
—
7,830
18,353
— 10,000
896

5,973

$

883
521
25
—
—
11,131
10,500
1,167

Total

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

$57,815

$39,455

$24,227

Deferred revenue of $41.2 million at June 30, 2015  represents payments  received from  our
collaborators pursuant to our license agreements which we have  yet to earn  pursuant to our  revenue
recognition policy. Included within this amount is a  $20 million upfront payment received from Takeda
during fiscal 2015 and $13 million of  non-cash consideration  recorded in connection  with our
arrangement with CytomX during fiscal  2014.

54

In February 2013, the US FDA granted marketing approval to Kadcyla,  an  ADC product  resulting
from one of our development and commercialization licenses  with Roche,  through its Genentech unit.
We  receive royalty reports and payments related to sales of Kadcyla  from Roche  one quarter in arrears.
In accordance with our revenue recognition policy,  $13.9 million of royalties  on net  sales of  Kadcyla for
the nine-month period ended December  31, 2014 were recorded  and included in royalty  revenue for
the year ended June 30, 2015 and $10.3 million of royalties on net sales of Kadcyla for  the twelve-
month period ended March 31, 2014 is  included in royalty revenue for the year ended June 30,  2014.
We  recorded $592,000 of royalties on  net sales of Kadcyla for the three-month period ended March  31,
2013 in our fourth quarter of fiscal 2013. Total  revenues  for  the  year ended June 30, 2015  also include
$5.5 million of non-cash royalty revenue  on  net sales  of Kadcyla for  the  three-month period  ended
March 31, 2015 as royalties on Kadcyla sales  occurring after January  1, 2015  are covered  by  a royalty
purchase agreement whereby the associated cash  is remitted to Immunity Royalty Holdings, L.P. See
further details regarding royalty obligation in  Note E of the Consolidated Financial  Statements. We
expect royalty revenue to increase in future periods as the underlying net  sales  of  Kadcyla increase.

Research and development support revenue was $2.8 million for the year ended  June 30, 2015,
$7.2 million for the year ended June 30,  2014, and $7.9 million for  the year  ended June 30, 2013.  These
amounts primarily represent research funding earned based on actual resources utilized under  our
agreements with our collaborators as shown in the table below. Also  included  in research and
development support revenue are fees for  developing antibody-specific conjugation processes on behalf
of our collaborators and potential collaborators  during the early evaluation and preclinical  testing
stages of drug development. The amount of research and development support  revenue we earn is
directly related to the number of our collaborators  and  potential collaborators,  the stage of
development of our collaborators’ product candidates and the resources our collaborators allocate to
the development effort. As such, the amount of development fees may vary  widely from quarter to
quarter and year to year. Total revenue  recognized from research and development support from each
of our collaborative partners in the years  ended June  30, 2015, 2014 and  2013 is included in  the
following table (in thousands):

Research and Development Support

Collaborative Partner:

Year Ended June 30,

2015

2014

2013

Amgen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Biotest . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Lilly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Novartis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Takeda . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Other . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

$ 105
645
1,207
512
264
115

$ 404
783
2,906
3,012
—
82

$ 417
921
806
5,605
—
124

Total . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

$2,848

$7,187

$7,873

Clinical materials revenue increased  by approximately $2.6  million to $5.5  million in the year

ended June 30, 2015 compared to $2.9 million in  the year ended June 30, 2014. We earned clinical
materials revenue of $2.8 million during  the year ended  June 30, 2013. During the years ended  June  30,
2015, 2014 and 2013, we shipped clinical materials  in support of  a  number of our collaborators’ clinical
trials, as well as preclinical materials in support of certain  collaborators’ development efforts and DMx
shipments to certain collaborators in  support of development and manufacturing efforts. We  are
compensated at negotiated prices which are generally consistent with  what other third-parties would
charge. The amount of clinical materials revenue  we earn, and the related  cost of clinical materials
charged to research and development  expense, is directly related to the number of clinical  trials our
collaborators who  use us to manufacture  clinical materials are preparing or have underway, the speed
of enrollment in those trials, the dosage  schedule  of each clinical trial and the time period, if  any,

55

during which patients in the trial receive clinical  benefit from  the clinical  materials,  and the  demand
our  collaborators have for clinical-grade material for process  development and  analytical  purposes. As
such, the amount of clinical materials  revenue and the related cost  of clinical  materials  charged to
research and development expense may  vary  significantly  from quarter to quarter and  year  to  year.

Research and Development Expenses

Our research and development expenses relate to (i) research to evaluate new targets  and to
develop and evaluate new antibodies, linkers and cytotoxic  agents,  (ii) preclinical testing  of our  own
and, in certain instances, our collaborators’  product candidates, and the cost of  our own clinical  trials,
(iii) development related to clinical and commercial manufacturing processes  and (iv)  manufacturing
operations which also includes raw materials. Our  research and development efforts have been
primarily focused in the following areas:

(cid:129) evaluation of potential antigen targets;

(cid:129) evaluation of internally developed and/or  in-licensed  product candidates  and technologies;

(cid:129) development and evaluation of additional cytotoxic agents and  linkers;

(cid:129) activities related to the process, preclinical  and clinical development of  our internal product

candidates;

(cid:129) process improvements to our ADC technology;

(cid:129) process improvements related to the production of DGN462;

(cid:129) process improvements related to the production of DM1,  DM4 and  strain  development of their

precursor, ansamitocin P3;

(cid:129) operation and maintenance of our conjugate manufacturing facility, including production of our

own and our collaborators’ clinical materials;

(cid:129) production costs for the supply of clinical material  for our  internal  product candidates, including

antibody  supply, conjugation services and fill/finish services;

(cid:129) production costs for the supply of DGN462  and  DMx for our and our partners’ preclinical and

clinical activities;

(cid:129) non-pivotal and pivotal development activities with contract manufacturers for conjugation, fill/
finish  services and the antibody component of our internal  product candidates, linkers, and
DM1, DM4 and their precursor, ansamitocin P3; and

(cid:129) activities pursuant to our development  and license agreements with various  collaborators.

Research and development expense for the  year  ended June  30, 2015 increased $4.8  million  to

$111.8 million from $107.0 million for the  year  ended June  30, 2014. Research  and development
expense was $87.1  million for the year  ended June 30, 2013.  During  the year  ended June 30, 2014,  we
recorded  a $12.8 million non-cash charge to research and development expense for technology rights
obtained under the collaboration agreement executed with  CytomX in January 2014. We had no such
charge  in fiscal year 2015. Offsetting  this  decrease were the  following  increases in expense in fiscal
2015: (i) increased third-party costs related to the advancement  of our  internal products; (ii) an
increase in cost of clinical materials revenue due to timing of orders of such clinical  materials  from our
partners; (iii) an increase in facility-related expenses  due primarily to additional laboratory and  office
space occupied since July 2014 and increased depreciation  and amortization related to major capital
equipment and improvements; and (iv) salaries and related expenses increased due primarily to
increases in personnel and incentive compensation. Research  and development salaries and related
expenses increased by $5.0 million to $52.6  million  in the year ended June 30,  2015 compared  to  the

56

year ended June 30, 2014 and increased by $8.3 million in  the year  ended June 30, 2014 compared to
the year ended June 30, 2013. The average number of our research personnel increased to 266 for the
year ended June 30, 2015 compared to 250 for the year ended  June  30, 2014. We had  an average of
226 for the year ended June 30, 2013.  Included in  salaries and related expenses for the year ended
June 30, 2015 is $9.9 million of stock compensation costs compared  to  $10.3 million  and $7.3 million  of
stock compensation costs for fiscal years 2014 and  2013, respectively. The higher stock  compensation
costs in fiscal years 2015 and 2014 compared  to  fiscal year 2013 are driven by increases in the number
of annual options granted due to increases in  personnel, as well as higher stock prices in fiscal 2014.

We  are unable to accurately estimate which  potential  product candidates, if  any, will eventually
move into our internal preclinical research program. We are unable  to  reliably  estimate the  costs to
develop these products as a result of  the uncertainties related to discovery research efforts as  well as
preclinical and clinical testing. Our decision to move a  product candidate into the  clinical development
phase is  predicated upon the results  of  preclinical  tests.  We  cannot accurately predict  which, if any, of
the discovery stage product candidates will  advance from preclinical testing and move into our internal
clinical development program. The clinical  trial  and  regulatory approval processes for our product
candidates that have advanced or that  we  intend to advance to clinical  testing  are lengthy,  expensive
and uncertain in both timing and outcome. As  a result,  the pace and timing of  the clinical  development
of our product candidates is highly uncertain and  may not ever  result in approved products.
Completion dates and development costs will vary significantly  for each product  candidate and  are
difficult to predict. A variety of factors,  many  of  which are outside our  control,  could  cause or
contribute to the prevention or delay of  the successful completion of  our clinical trials, or  delay or
prevent our obtaining necessary regulatory approvals. The  costs to take a product through clinical trials
are dependent upon, among other factors, the  clinical indications, the  timing, size and design  of each
clinical trial, the number of patients enrolled in each trial, and the speed at which patients are enrolled
and treated. Product candidates may be found to be ineffective or to cause unacceptable side  effects
during clinical trials, may take longer  to  progress through clinical  trials than anticipated,  may fail to
receive necessary regulatory approvals  or  may  prove  impractical  to  manufacture  in commercial
quantities at reasonable cost or with  acceptable quality.

The lengthy process of securing FDA  approvals for new drugs requires the  expenditure of

substantial resources. Any failure by us  to  obtain, or any delay  in obtaining, regulatory approvals, would
materially adversely affect our product development  efforts and  our business overall.  Accordingly, we
cannot currently estimate, with any degree of certainty, the amount of time or  money  that  we will be
required to expend in the future on our product  candidates prior  to  their regulatory approval, if such
approval is ever granted. As a result of  these uncertainties  surrounding  the timing and outcome of our
clinical trials, we are currently unable to estimate  when, if  ever, our product  candidates that have
advanced into clinical testing will generate  revenues and cash flows.

We  do not track our research and development  costs by project. Since we use our research and
development resources across multiple research and development  projects,  we manage our research and
development expenses within each of the categories listed in the following table and described in more
detail below (in thousands):

Research and Development Expense

Year Ended June 30,

2015

2014

2013

Research . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Preclinical and Clinical Testing . . . . . . . . . . . . . . . .
Process and Product Development . . . . . . . . . . . . . .
Manufacturing Operations . . . . . . . . . . . . . . . . . . .

$ 20,729
42,546
8,468
40,025

$ 30,793
34,562
8,296
33,307

$17,506
27,839
7,777
33,951

Total Research and Development Expense . . . . . . . .

$111,768

$106,958

$87,073

57

Research—Research includes expenses associated with  activities to evaluate new targets and  to

develop and evaluate new antibodies, linkers and cytotoxic  agents  for our  products and in  support of
our  collaborators. Such expenses primarily include personnel, fees to in-license certain technology,
facilities and lab supplies. Research expenses decreased  $10.1 million to $20.7 million in  fiscal  year
2015 from fiscal year 2014 and increased $13.3 million  to  $30.8 million in fiscal year 2014  from fiscal
year 2013. This decrease in fiscal year  2015 was principally due  to  a  $12.8 million non-cash charge
recorded  for technology rights obtained  under the  collaboration agreement executed with CytomX in
January 2014, partially offset by an increase in salaries  and related expenses  and an  increase in facility-
related expenses. The increase in fiscal  2014  from fiscal 2013 was principally due to the $12.8 million
non-cash charge noted above, and to  a  lesser extent, an increase in  salaries and related  expenses.

Preclinical and Clinical Testing—Preclinical and clinical testing includes expenses  related to

preclinical testing of our own and, in  certain instances,  our collaborators’ product candidates,  regulatory
activities, and the cost of our own clinical  trials.  Such expenses include personnel, patient enrollment at
our  clinical testing sites, consultant fees, contract  services,  and facility expenses. Preclinical and  clinical
testing expenses increased $7.9 million  to  $42.5 million in  fiscal  year 2015 from fiscal  year 2014 and
$6.8 million to $34.6 million in fiscal  year 2014 from fiscal year 2013. The increase in  fiscal year  2015
was principally the result of an increase in contract service expense driven primarily by increased study
activities related to mirvetuximab soravtansine and  IMGN289,  and to a lesser extent, higher salaries
and related expenses and an increase  in  facility-related  expenses. Partially offsetting these increases,
clinical trial costs decreased marginally  due primarily to decreased costs incurred related to the
IMGN901 007 study, partially offset by  increased costs related to the mirvetuximab  soravtansine and
IMGN529 studies during the current  year. The increase  in fiscal  year 2014  was principally the  result of
higher  salaries and related expenses driven by an increase in personnel and higher stock  compensation
costs.

Process and Product Development—Process and product development expenses include costs  for

development of clinical and commercial manufacturing processes for our own and collaborator
compounds. Such expenses include the costs of personnel, contract services and facility expenses.  Total
development expenses increased $172,000 to $8.5 million in fiscal year  2015 from fiscal year 2014  and
expenses increased $519,000 to $8.3 million in fiscal year 2014  from fiscal year 2013. The  increase in
fiscal year 2015 was primarily the result of an increase in facility-related expenses. The increase  in fiscal
year 2014 was primarily the result of an  increase in salaries and related expenses,  as well as an increase
in contract service expense in fiscal 2014 driven primarily by  development activities  for IMGN779.

Manufacturing Operations—Manufacturing operations expense  includes costs to manufacture
preclinical and clinical materials for our  own and  our  collaborators’ product candidates, quality control
and quality assurance activities and costs to support  the operation  and maintenance of our conjugate
manufacturing facility. Such expenses include personnel, raw materials for  our  and our collaborators’
preclinical studies and clinical trials, non-pivotal and pivotal  development costs  with contract
manufacturing organizations, manufacturing supplies, and facilities expense. Manufacturing operations
expense increased $6.7 million to $40.0  million  in fiscal year 2015 from fiscal year 2014 and decreased
$644,000 to $33.3 million in fiscal year 2014 from  fiscal  year 2013. The increase  in fiscal year 2015 was
primarily the result of i) an increase in  cost of clinical materials revenue charged to research and
development expense due to timing of orders of such  clinical  materials  from our partners; (ii) an
increase in contract service expense driven by increased third-party conjugation activities to prepare for
commercial-scale and increased cytotoxic agent activities; (iii) an increase  in antibody development and
supply expense driven primarily by commercial-ready activities for mirvetuximab soravtansine; and
(iv) an increase in salaries and related expenses driven by increased personnel  and increased incentive
compensation. The decrease in fiscal year 2014 was primarily the  result of (i) a decrease in antibody
development and supply expense driven  primarily by supply required  in fiscal  2013 for  our  currently
discontinued IMGN289 and IMGN901  programs, as well  as pivotal  activities  performed for our

58

IMGN901 program, partially offset by non-pivotal  activities performed and supply  required for our
IMGN779 program during fiscal 2014;  (ii) a decrease in fill/finish  costs due primarily to costs  to
transfer our internal programs to a new supplier during  fiscal 2013;  and  (iii) an increase  in costs
capitalized into inventory due to a greater number of manufactured batches of conjugated materials on
behalf of our collaborators. Partially offsetting these cost decreases, salaries and related  expenses
increased during fiscal 2014 and contract  service expense increased due primarily to increased study
activities related to our cytotoxic agents.

Antibody development and supply expense in anticipation of  potential future clinical trials, as  well

as our ongoing trials, was $8.8 million  in fiscal year 2015, $7.2 million  in fiscal year 2014, and
$10.8 million in fiscal year 2013. The process  of antibody production  is lengthy  due  in part to the lead
time to establish a satisfactory production process at  a vendor. Accordingly,  costs incurred related to
antibody  production and development  have fluctuated from period to period  and we expect these  cost
fluctuations to continue in the future.

We  expect that future research and development  expenses will increase, including  salaries and
related expenses, due to our continuing  advancement  and support of our internal product candidates
through clinical trials.

General and Administrative Expenses

General and administrative expenses  for the  year ended June 30, 2015  increased $3.7 million  to
$28.2 million from $24.5 million for the  year ended June 30, 2014.  General and administrative expenses
for the year ended June 30, 2013 were  $21.5 million.  The increases in  fiscal years 2015 and 2014 were
primarily due to increases in salaries  and related expenses, as well as increases  in professional service
fees, particularly consulting fees and patent expenses.  We expect general and administrative  expenses to
increase marginally in fiscal 2016 compared to fiscal 2015  due primarily  to increases in salaries  and
related expenses.

Investment Income, net

Investment income for the years ended June 30, 2015,  2014 and 2013 was $69,000,  $44,000 and

$126,000, respectively.

Non-Cash Interest Expense on Liability Related  to Sale of  Future  Royalty

In April 2015, Immunity Royalty Holdings, L.P. (IRH) purchased our right to receive 100%  of the
royalty payments on commercial sales of  Kadcyla arising under our development and commercialization
license with Genentech, until IRH has  received  aggregate royalties equal  to  $235 million or
$260 million, depending on when the aggregate royalties received by IRH reach a specified  milestone.
As described in Note E to our Consolidated Financial Statements,  this royalty  sale transaction  has been
recorded  as a liability that amortizes  over  the estimated royalty payment period as Kadcyla royalties are
remitted directly to the purchaser. We impute interest  on the transaction and  record interest  expense at
the effective interest rate, which we currently estimate to be approximately  10%. There are  a number
of factors that could materially affect  the estimated interest  rate,  in particular, the amount and timing
of royalty payments from future net  sales  of Kadcyla, and we will assess this estimate on a  periodic
basis. As a result, future interest rates  could differ significantly and  any such change in  interest rate will
be adjusted prospectively.

Other (Expense) Income, net

Other (expense) income, net for the  years ended June 30,  2015, 2014 and 2013  was  $(916,000),

$123,000 and $72,000, respectively. We  incurred $(910,000), $120,000, and $(153,000)  in foreign
currency exchange (losses) and gains  related to obligations with non-U.S. dollar-based suppliers and

59

Euro  cash balances maintained to fulfill them during the years ended  June  30, 2015, 2014  and 2013,
respectively, and we recorded net gains on foreign  currency forward contracts of $2,000 and  $197,000 in
fiscal years 2014 and 2013, respectively.

Liquidity and Capital Resources

Cash and cash equivalents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Working capital
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Shareholders’ equity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

$278,109
256,370
35,104

$142,261
129,502
75,699

Year Ended June 30,

2015

2014

2013

As of June 30,

2015

2014

(In thousands)

Cash used for operating activities . . . . . . . . . . . . . . . . . . . .
Cash used for investing activities . . . . . . . . . . . . . . . . . . . . .
Cash provided by financing activities . . . . . . . . . . . . . . . . . .

Cash Flows

(In thousands)
$ (55,291) $(53,650) $(60,299)
(3,696)
98,017

(7,425)
198,564

(8,185)
9,136

We  require cash to fund our operating  expenses, including the advancement  of our  own clinical

programs, and to make capital expenditures. Historically,  we  have funded our  cash requirements
primarily through equity financings in public  markets and payments from  our collaborators, including
license fees, milestones, research funding  and more recently, royalties. As of June 30,  2015, we  had
approximately $278.1 million in cash  and cash equivalents. Net cash used for operating  activities was
$55.3 million, $53.7 million and $60.3  million during the years ended  June  30, 2015, 2014  and 2013,
respectively. The principal use of cash  in  operating activities for all  periods  presented  was  to  fund  our
net loss, adjusted for non-cash items. Cash  used  for  operating activities in fiscal 2015  benefited from
the $20 million upfront payment received from Takeda in March 2015  with the  execution  of a right-
to-test  agreement between the companies.

Net cash used for investing activities  was $7.4  million,  $8.2 million and $3.7 million for  the years

ended June 30, 2015, 2014 and 2013,  respectively,  and  substantially  represents cash  outflows  from
capital expenditures. Capital expenditures  were $7.4  million,  $8.2 million and  $3.8 million for  the fiscal
years ended June 30, 2015, 2014 and  2013, respectively. Capital expenditures for  the years ended
June 30, 2015, 2014 and 2013 consisted primarily of leasehold improvements to the laboratory and
office space at our corporate headquarters and manufacturing facility, laboratory equipment and
computer software applications.

Net cash provided by financing activities was  $198.6 million,  $9.1 million and  $98.0 million for  the
years ended June 30, 2015, 2014 and  2013, respectively, which includes  the proceeds  from the exercise
of approximately 651,000, 1.1 million  and  666,000 stock  options, respectively. Also,  pursuant to a public
offering, in fiscal 2013, we issued and sold 6,250,000  shares of our common stock  resulting in net
proceeds of $94.0 million.

As discussed above, in April 2015, Immunity Royalty  Holdings,  L.P. purchased  our  right to receive
100% of the royalty payments on commercial  sales of  Kadcyla. At consummation  of the transaction in
April 2015, we received gross cash proceeds of $200  million. We  recorded  these  cash proceeds as a
deferred royalty obligation liability which is being amortized  over the expected royalty recovery  period.
As part of this transaction, the Company  incurred approximately $5.9 million in transaction  costs.

60

We  anticipate that our current capital resources and expected  future collaborator payments under

existing collaborations will enable us  to  meet our operational expenses and capital expenditures through
fiscal year 2017. However, we cannot  provide assurance that such collaborative agreement  funding  will,
in fact, be received. Should we or our  partners  not  meet some or all  of the terms and  conditions of our
various collaboration agreements, we may  be  required to pursue additional strategic partners, secure
alternative financing arrangements, and/or  defer or limit  some or all of  our  research,  development
and/or clinical projects.

Contractual Obligations

Below is a table that presents our contractual  obligations  and commercial  commitments  as of

June 30, 2015 (in thousands):

Waltham lease obligations(1) . . . . . . . . . . . . . . . .
Other operating lease obligations(1)
. . . . . . . . . .
Liability related to the sale of future royalties(2)
.

Payments Due by Period

Total

$ 69,893
3.359
199,662

Less than
One Year

$ 6,028
1,102
7,906

1-3
Years

4-5
Years

More than
5 Years

$12,173
2,227
54,219

$ 12,835
30
88,290

$38,857
—
49,247

Total

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

$272,914

$15,036

$68,619

$101,155

$88,104

(1) Lease agreements were signed in July 2007,  November 2010  and April 2013, and amended in

December 2013 and April 2014. In December 2014, we entered into a sublease for  7,507 square
feet of office space at 100 River Ridge Drive, Norwood, MA  through July  2018. We will receive
approximately $370,000 in minimum  rental  payments over the remaining term of the  sublease,
which  is not included in the table above.

(2)

See  Note E to the Consolidated Financial Statements in Item 8  for discussion of this liability.

In addition to the above table, we are  contractually obligated to make future success-based

development, regulatory or sales milestone payments  in conjunction with certain  collaborative
agreements. These payments are contingent upon the occurrence of certain future events and, given the
nature of these events, it is unclear when, if ever,  we may  be  required to  pay such amounts. Therefore,
the timing of any future payment is not reasonably estimable.  As a result, these  contingent payments
have not been included in the table above or recorded in our consolidated  financial  statements.

As of June 30, 2015, the maximum amount that may be payable  in the future under  our current
collaborative agreements is $162 million,  $1.4 million of which  is reimbursable by a third party under a
separate agreement.

Recent  Accounting Pronouncements

In May 2014, the FASB issued Accounting Standards Update  2014-9, Revenue from Contracts with
Customers (Topic 606) (‘‘ASU 2014-09’’), to clarify the principles for recognizing  revenue. This update
provides a comprehensive new revenue  recognition model that  requires revenue to be recognized in  a
manner to depict the transfer of goods or services  to  a customer at an amount that reflects the
consideration expected to be received  in exchange for  those goods or services. The original effective
date  would have required us to adopt beginning  in our first quarter of  fiscal  2018. In July  2015, the
FASB voted to amend ASU 2014-09  by  approving a  one-year deferral  of the effective date as well  as
providing the option to early adopt the standard  on the  original effective date.  Accordingly, we may
adopt the standard in either our first  quarter of fiscal  2018  or 2019.  The  new revenue standard allows
for either full retrospective or modified retrospective application. We  are currently evaluating the

61

timing of  its adoption and the impact that  this guidance will  have on our  consolidated financial
statements and related disclosures.

In August 2014, the FASB issued Accounting Standards  Update  2014-15, Presentation of Financial

Statements-Going Concern (Subtopic 205-40): Disclosure of  Uncertainties about  an  Entity’s Ability to
Continue as a Going Concern. This new standard gives a company’s  management  the final
responsibilities to decide whether there’s  substantial doubt  about the  company’s ability to continue  as a
going concern and to provide related footnote  disclosures. The standard provides  guidance to
management, with principles and definitions that are  intended to reduce  diversity in  the timing and
content of disclosures that companies  commonly  provide  in their footnotes. Under the new standard,
management must decide whether there  are conditions or  events, considered  in the aggregate, 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,  or within one  year after the date that the financial
statements are available to be issued  when applicable. This guidance is effective for annual reporting
beginning after December 15, 2016, including interim periods  within the year of adoption,  with early
application permitted. Accordingly, the standard is effective for us  on  July 1,  2017. The adoption of this
guidance is not expected to have a material impact on  our consolidated financial statements.

In April 2015, the FASB issued Accounting  Standards Update 2015-03, Interest-Imputation  of
Interest (Subtopic 835-30): Simplifying the  Presentation of  Debt Issuance Costs. To simplify presentation of
debt issuance costs, this new standard requires that debt issuance costs  related to a recognized debt
liability be presented in the balance sheet  as a  direct  deduction from the  carrying amount of that debt
liability, consistent with debt discounts. The recognition and measurement guidance  for debt issuance
costs are not affected by this update. This  guidance is effective  for annual reporting beginning after
December 15, 2015, including interim  periods within  the year of adoption, and calls for retrospective
application, with early application permitted. Accordingly, the standard  is effective for us on  July 1,
2016. We are currently evaluating the impact that this guidance will have  on our consolidated financial
statements.

In July 2015, the FASB issued Accounting Standards  Update 2015-11, Simplifying the Measurement
of Inventory (Topic 330). To simplify the principles for subsequent measurement of inventory, this  new
standard requires inventory measured  using any method other than LIFO or  the retail method shall be
measured at the lower of cost and net realizable value,  rather than lower  of  cost or market. This
guidance is effective for annual reporting  beginning  after December 15, 2016,  including interim  periods
within the year of  adoption, and calls  for prospective application, with early application permitted.
Accordingly, the standard is effective  for  us on July  1, 2017. The adoption  of  this  guidance is not
expected to have a material impact on  our consolidated  financial statements.

Off-Balance Sheet Arrangements

None.

Item 7A. Quantitative and Qualitative Disclosure About  Market Risk

We  maintain an investment portfolio in accordance with our investment policy. The primary

objectives of our investment policy are to preserve  principal, maintain proper liquidity  to  meet
operating needs and maximize yields. Although our  investments are subject to credit  risk, our
investment policy specifies credit quality standards for our investments  and limits the  amount  of credit
exposure from any single issue, issuer or type  of investment. Our investments are  also subject  to
interest rate risk and will decrease in  value  if  market  interest rates  increase. However,  due  to  the
conservative nature of our investments and relatively  short duration, interest rate risk  is mitigated.  We
do not currently own derivative financial  instruments in our investment  portfolio.  Accordingly,  we do

62

not believe there is any material market risk exposure with respect to derivative or other financial
instruments that would require disclosure  under this  item.

Our foreign currency hedging program uses either forward  contracts or a Euro-denominated bank

account to manage the foreign currency  exposures that  exist as  part  of  our ongoing business operations.
Our foreign currency risk management  strategy is principally  designed to mitigate the  future potential
financial impact of changes in the value  of transactions, anticipated transactions  and balances
denominated in foreign currency, resulting from  changes in  foreign currency exchange rates.  Our
market risks associated with changes  in  foreign  currency exchange  rates are currently limited to a
Euro-denominated bank account as we  have no forward  contracts  at June 30, 2015.

63

Item 8. Financial Statements and Supplementary Data

IMMUNOGEN, INC.
INDEX TO CONSOLIDATED FINANCIAL STATEMENTS

Report of Independent Registered Public  Accounting  Firm . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Consolidated Financial Statements:

Consolidated Balance Sheets as of June 30,  2015 and 2014 . . . . . . . . . . . . . . . . . . . . . . . . . . .
Consolidated Statements of Operations  and  Comprehensive  Loss for the Years Ended  June  30,
2015, 2014, and 2013 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Consolidated Statements of Shareholders’ Equity for the Years Ended  June 30, 2015, 2014,

and 2013 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Consolidated Statements of Cash Flows  for  the Years  Ended June 30,  2015, 2014, and 2013 . . .
Notes to Consolidated Financial Statements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Page

65

66

67

68
69
70

64

Report of Independent Registered Public Accounting Firm

The Board of Directors and Shareholders  of ImmunoGen, Inc.

We  have audited the accompanying consolidated balance sheets of ImmunoGen, Inc. as  of  June 30,

2015 and 2014, and the related consolidated  statements  of operations  and  comprehensive loss,
shareholders’ equity and cash flows for  each of the three years  in the  period ended  June 30, 2015.
These financial statements are the responsibility of the Company’s management. Our  responsibility is to
express an opinion on these financial statements based on our  audits.

We  conducted our audits in accordance with the standards  of  the Public Company Accounting
Oversight Board (United States). Those  standards require that we  plan and perform the audit to obtain
reasonable assurance about whether  the  financial  statements are free  of material misstatement.  An
audit includes examining, on a test basis, evidence  supporting the amounts and disclosures  in the
financial statements. An audit also includes assessing the accounting  principles used  and significant
estimates made by management, as well as  evaluating the overall financial statement presentation. We
believe that our audits provide a reasonable  basis for our opinion.

In our opinion, the financial statements referred to above present fairly, in all material respects,

the consolidated financial position of  ImmunoGen, Inc. at June 30, 2015  and 2014, and  the
consolidated results of its operations and  its cash  flows  for  each  of the three years in the period ended
June 30, 2015, in conformity with U.S. generally accepted accounting principles.

We  also have audited, in accordance  with the standards of  the Public Company Accounting
Oversight Board (United States), ImmunoGen, Inc.’s internal control over  financial reporting  as of
June 30, 2015, based on criteria established  in Internal Control—Integrated Framework  issued by the
Committee of Sponsoring Organizations  of  the Treadway  Commission (2013 framework) and our report
dated August 27, 2015 expressed an unqualified opinion  thereon.

/s/ Ernst & Young LLP

Boston, Massachusetts
August 27, 2015

65

IMMUNOGEN, INC.

CONSOLIDATED BALANCE SHEETS

In thousands, except per share amounts

ASSETS
Cash and cash equivalents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Accounts receivable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Unbilled revenue . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Inventory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Current portion of deferred financing  costs . . . . . . . . . . . . . . . . . . . . . . . . . . .
Prepaid and other current assets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Total current assets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Property and equipment, net of accumulated depreciation . . . . . . . . . . . . . . . .
Deferred financing costs, net of current  portion . . . . . . . . . . . . . . . . . . . . . . .
Other assets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

June 30,
2015

June 30,
2014

$ 278,109
5,088
714
2,935
1,159
4,175

292,180
16,254
4,415
974

$ 142,261
1,896
1,329
2,950
—
2,320

150,756
14,349
—
213

Total assets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

$ 313,823

$ 165,318

LIABILITIES AND SHAREHOLDERS’ EQUITY
Accounts payable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Accrued compensation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Other accrued liabilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Current portion of deferred lease incentive . . . . . . . . . . . . . . . . . . . . . . . . . . .
Current portion of liability related to the sale  of future royalties . . . . . . . . . . .
Current portion of deferred revenue . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Total current liabilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Deferred lease incentive, net of current  portion . . . . . . . . . . . . . . . . . . . . . . .
Deferred revenue, net of current portion . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Liability related to the sale of future royalties, net of current portion . . . . . . . .
Other long-term liabilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Total liabilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Commitments and contingencies (Note  H)
Shareholders’ equity:
Preferred stock, $.01 par value; authorized  5,000 shares; no  shares  issued and

$

8,138
8,346
10,441
646
7,906
333

35,810
6,301
40,855
191,756
3,997

278,719

$

4,819
6,865
6,668
528
—
2,374

21,254
5,679
58,969
—
3,717

89,619

outstanding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

—

—

Common stock, $.01 par value; authorized 150,000 shares; issued and
outstanding 86,579 and 85,903 shares  as of June  30, 2015 and 2014,
respectively . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Additional paid-in capital
Accumulated deficit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

866
743,108
(708,870)

859
722,971
(648,131)

Total shareholders’ equity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

35,104

75,699

Total liabilities and shareholders’ equity . . . . . . . . . . . . . . . . . . . . . . . .

$ 313,823

$ 165,318

The accompanying notes are an integral part of the consolidated financial statements.

66

CONSOLIDATED STATEMENTS OF  OPERATIONS AND COMPREHENSIVE LOSS

In thousands, except per share amounts

IMMUNOGEN, INC.

Year Ended June 30,

2015

2014

2013

Revenues:

License and milestone fees . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Royalty revenue . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Non-cash royalty revenue related to the  sale of  future royalties
. . .
Research and development support . . . . . . . . . . . . . . . . . . . . . . . .
Clinical materials revenue . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

$ 57,815
13,867
5,484
2,848
5,527

$ 39,455
10,346
—
7,187
2,908

$ 24,227
592
—
7,873
2,843

Total revenues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

85,541

59,896

35,535

Operating Expenses:

Research and development . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
General and administrative . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

111,768
28,228

106,958
24,469

87,073
21,471

Total operating expenses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

139,996

131,427

108,544

Loss from operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Investment income, net . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Non-cash interest expense on liability related to the  sale of future

(54,455)
69

(71,531)
44

(73,009)
126

royalties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Other (expense) income, net . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

(5,437)
(916)

—
123

—
72

Net loss . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

$ (60,739) $ (71,364) $ (72,811)

Basic and diluted net loss per common share . . . . . . . . . . . . . . . . . .

$

(0.71) $

(0.83) $

(0.87)

Basic and diluted weighted average common shares outstanding . . . . .

86,038

85,481

84,063

Other comprehensive loss . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

—

—

—

Total comprehensive loss . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

$ (60,739) $ (71,364) $ (72,811)

The accompanying notes are an integral part of the consolidated financial statements.

67

CONSOLIDATED STATEMENTS OF SHAREHOLDERS’ EQUITY

IMMUNOGEN, INC.

In thousands

Common Stock

Shares

Amount

Balance at June 30, 2012 . . . . . . . . . . . . . . . . .
Net loss . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Stock options exercised . . . . . . . . . . . . . . . . . .
Restricted stock award . . . . . . . . . . . . . . . . . .
Stock-based compensation expense . . . . . . . . . .
Issuance of common stock in a public  offering,

77,759
—
666
50
—

net of issuance costs . . . . . . . . . . . . . . . . . .
Directors’ deferred share unit compensation . . .

6,250
—

$778
—
6
—
—

63
—

Additional
Paid-In
Capital

$587,068
—
4,020
—
12,400

93,928
351

Accumulated
Deficit

$(503,956)
(72,811)
—
—
—

Total
Shareholders’
Equity

$ 83,890
(72,811)
4,026
—
12,400

—
—

93,991
351

Balance at June 30, 2013 . . . . . . . . . . . . . . . . .

84,725

$847

$697,767

$(576,767)

$121,847

Net loss . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Stock options exercised . . . . . . . . . . . . . . . . . .
Stock-based compensation expense . . . . . . . . . .
Directors’ deferred share units converted . . . . .
Directors’ deferred share unit compensation . . .

—
1,134
—
44
—

—
11
—
1
—

—
9,125
15,647
(1)
433

(71,364)
—
—
—
—

(71,364)
9,136
15,647
—
433

Balance at June 30, 2014 . . . . . . . . . . . . . . . . .

85,903

$859

$722,971

$(648,131)

$ 75,699

Net loss . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Stock options exercised . . . . . . . . . . . . . . . . . .
Restricted stock award . . . . . . . . . . . . . . . . . .
Stock-based compensation expense . . . . . . . . . .
Directors’ deferred share unit compensation . . .

—
651
25
—
—

—
7
—
—
—

—
4,422
—
15,326
389

(60,739)
—
—
—
—

(60,739)
4,429
—
15,326
389

Balance at June 30, 2015 . . . . . . . . . . . . . . . . .

86,579

$866

$743,108

$(708,870)

$ 35,104

The accompanying notes are an integral part of the consolidated financial statements.

68

IMMUNOGEN, INC.

CONSOLIDATED STATEMENTS OF CASH FLOWS

In thousands

Cash flows from operating activities:
Net loss . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Adjustments to reconcile net loss to net  cash used for operating

activities:
Non-cash royalty revenue related to sale of future royalties . . . . . .
Non-cash interest expense on liability related to sale of future

royalties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Depreciation and amortization . . . . . . . . . . . . . . . . . . . . . . . . . . .
Loss (Gain) on sale/disposal of fixed assets . . . . . . . . . . . . . . . . . .
Gain on forward contracts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Non-cash licensing fee . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Stock and deferred share unit compensation . . . . . . . . . . . . . . . . .
Deferred rent
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Change in operating assets and liabilities:

Accounts receivable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Unbilled revenue . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Inventory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Prepaid and other current assets . . . . . . . . . . . . . . . . . . . . . . . .
Restricted cash . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Other assets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Accounts payable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Accrued compensation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Other accrued liabilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Deferred revenue, net of non-cash upfront  license payment . . . . .
Proceeds from landlord for tenant improvements . . . . . . . . . . . .

Year Ended June 30,

2015

2014

2013

$ (60,739) $ (71,364) $ (72,811)

(5,484)

—

—

5,437
5,513
7
—
—
15,715
195

(3,192)
615
15
(1,855)
—
(761)
3,319
1,481
3,248
(20,155)
1,350

—
4,598
20
(2)
12,830
16,080
297

(1,896)
792
(2,247)
571
2,231
4
321
712
(394)
(16,675)
472

—
4,641
(21)
(197)
—
12,751
(109)

129
(925)
585
(181)
319
(43)
1,103
1,211
481
(7,232)
—

Net cash used for operating activities . . . . . . . . . . . . . . . . . . .

(55,291)

(53,650)

(60,299)

Cash flows from investing activities:

Purchases of property and equipment, net . . . . . . . . . . . . . . . . .
(Payments) proceeds from settlement  of forward contracts . . . . .

Net cash used for investing activities . . . . . . . . . . . . . . . . . . .

(7,425)
—

(7,425)

(8,184)
(1)

(8,185)

(3,770)
74

(3,696)

Cash flows from financing activities:

Proceeds from stock options exercised . . . . . . . . . . . . . . . . . . . .
Proceeds from sale of future royalties, net  of $5,865 of

4,429

9,136

4,026

transaction costs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . .

Proceeds from common stock issuance,  net

194,135
—

—
—

Net cash provided by financing activities . . . . . . . . . . . . . . . . .

198,564

9,136

—
93,991

98,017

Net change in cash and cash equivalents . . . . . . . . . . . . . . . . . . . . . .
Cash and cash equivalents, beginning  of period . . . . . . . . . . . . . . . . .

135,848
142,261

(52,699)
194,960

34,022
160,938

Cash and cash equivalents, end of period . . . . . . . . . . . . . . . . . . . . .

$278,109

$142,261

$194,960

The accompanying notes are an integral part of the consolidated financial statements.

69

IMMUNOGEN, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS

AS OF JUNE 30, 2015

A. Nature of Business and Plan of Operations

ImmunoGen, Inc. (the Company) was incorporated  in Massachusetts in 1981 and  is focused on the

development of antibody-based anticancer therapeutics.  The Company has  incurred operating losses
and negative cash flows from operations since inception, incurred a net  loss of approximately
$60.7 million during the fiscal year ended  June  30, 2015, and has  an accumulated deficit of
approximately $708.9 million as of June  30,  2015. The Company has primarily funded these  losses
through payments received from its collaborations and equity financings. To date, the Company  has no
product  revenue and management expects operating  losses to continue for the foreseeable future.

At June  30, 2015, the Company had $278.1 million of cash and cash equivalents  on hand. The
Company may raise additional funds through equity or  debt financings or generate revenues  from
collaborative partners through a combination  of upfront license  payments,  milestone payments, royalty
payments, research funding, and clinical  material reimbursement. There can be no assurance  that  the
Company will be able to obtain additional debt or  equity  financing or  generate revenues from
collaborative partners on terms acceptable  to  the Company  or  at  all. The  failure of the Company to
obtain sufficient funds on acceptable terms when needed  could have a material adverse effect on the
Company’s business, results of operations  and  financial condition and require the Company  to  defer  or
limit some or all of its research, development and/or clinical projects.

The Company is subject to risks common to companies in the biotechnology industry including, but
not limited to, the development by its  competitors of  new technological innovations, dependence  on key
personnel, protection of proprietary technology,  manufacturing  and  marketing limitations, collaboration
arrangements, third-party reimbursements  and  compliance with governmental regulations.

B. Summary of Significant Accounting Policies

Principles of Consolidation

The consolidated financial statements  include the accounts  of the Company  and its wholly owned

subsidiaries, ImmunoGen Securities Corp., ImmunoGen Europe Limited and Hurricane, LLC. All
intercompany transactions and balances have been eliminated.

Use of Estimates

The preparation of financial statements  in conformity with  accounting principles generally accepted

in the United States (U.S.) requires management to make estimates and assumptions that affect the
reported amounts of assets and liabilities and disclosure  of  contingent assets and liabilities at the date
of the financial statements and the reported  amounts of revenues and  expenses during the reporting
period. Actual results could differ from  those  estimates.

Subsequent Events

The Company has evaluated all events or transactions  that  occurred after  June 30, 2015 up

through the date the Company issued  these financial  statements. The Company did not have any
material recognizable or unrecognizable subsequent events.

70

IMMUNOGEN, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

AS OF JUNE 30, 2015

B. Summary of Significant Accounting Policies (Continued)

Revenue Recognition

The Company enters into licensing and development agreements with collaborative partners for
the development of monoclonal antibody-based anticancer therapeutics. The terms of  these agreements
contain multiple deliverables which may include (i) licenses, or options to  obtain  licenses, to the
Company’s antibody-drug conjugate, or  ADC,  technology, (ii) rights to future technological
improvements, (iii) research activities  to  be  performed on behalf  of  the collaborative partner,
(iv) delivery of cytotoxic agents and (v) the manufacture of preclinical or  clinical materials for the
collaborative partner. Payments to the Company  under these agreements  may  include upfront fees,
option fees, exercise fees, payments for research activities, payments for  the  manufacture of preclinical
or clinical materials, payments based upon  the achievement  of certain milestones  and royalties on
product  sales. The Company follows the provisions of the Financial Accounting Standards  Board
(FASB) Accounting Standards Codification (ASC)  Topic  605-25,  ‘‘Revenue Recognition—Multiple-
Element Arrangements,’’ and ASC Topic  605-28, ‘‘Revenue  Recognition—Milestone Method,’’ in
accounting for these agreements. In order to account for these agreements, the  Company must identify
the deliverables included within the agreement and evaluate  which deliverables  represent separate  units
of accounting based on whether certain criteria  are met, including  whether the delivered element  has
stand-alone value to the collaborator. The consideration  received is allocated among the separate units
of accounting, and the applicable revenue  recognition  criteria are applied to each of the  separate units.

At June  30, 2015, the Company had the following two types of  agreements with the  parties

identified below:

(cid:129) Development and commercialization licenses,  which provide  the party with  the right to use the
Company’s ADC technology and/or certain  other intellectual property to develop compounds to
a specified antigen target:

Amgen (four exclusive single-target licenses(1)) 

Bayer HealthCare (one exclusive single-target  license)

Biotest (one exclusive single-target license)

Lilly (three exclusive single-target licenses)

Novartis (five exclusive single-target licenses  and  one  license  to  two related targets:  one  target
on an exclusive basis and the second target  on a  non-exclusive  basis)

Roche, through its Genentech unit (five exclusive single-target licenses)

Sanofi (one exclusive single-target license and one exclusive license to multiple individual
targets)

(cid:129) Research license/option agreement  for a defined period  of  time  to  secure  development and
commercialization licenses to use the Company’s ADC technology to develop anticancer

(1) Amgen has sublicensed one of its exclusive single-target licenses to Oxford BioTherapeutics  Ltd.

71

IMMUNOGEN, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

AS OF JUNE 30, 2015

B. Summary of Significant Accounting Policies (Continued)

compounds to specified targets on established terms (referred  to  herein as right-to-test
agreements):

Sanofi

CytomX

Takeda, through its wholly owned subsidiary, Millennium Pharmaceuticals, Inc.

There are no performance, cancellation,  termination  or refund provisions in any of the

arrangements that contain material financial  consequences  to  the  Company.

Development and Commercialization  Licenses

The deliverables under a development and commercialization  license agreement  generally  include
the license to the Company’s ADC technology with respect to a specified  antigen target, and  may also
include deliverables related to rights  to  future technological improvements, research activities to be
performed on behalf of the collaborative  partner and the manufacture of preclinical or clinical
materials for the collaborative partner.

Generally, development and commercialization licenses contain non-refundable terms  for payments

and, depending on the terms of the agreement, provide  that the Company  will (i) at  the collaborator’s
request, provide research services at  negotiated  prices which  are generally consistent with what  other
third parties would charge, (ii) at the collaborator’s request, manufacture and provide to it preclinical
and clinical materials or deliver cytotoxic  agents at  negotiated prices which are  generally consistent with
what other third parties would charge, (iii)  earn payments upon the  achievement of certain milestones
and (iv) earn royalty payments, generally until  the later  of the last applicable  patent  expiration or  10 to
12 years after product launch. In the case of Kadcyla, however, the minimum royalty term  is 10  years
and the maximum royalty term is 12  years  on a  country-by-country basis,  regardless of  patent
protection. Royalty rates may vary over the royalty  term depending  on the  Company’s intellectual
property rights and/or the presence of comparable competing  products. The Company may provide
technical assistance and share any technology improvements with its  collaborators during the term  of
the collaboration agreements. The Company does  not directly  control when or whether any collaborator
will request research or manufacturing services, achieve milestones  or become liable for royalty
payments. As a result, the Company cannot  predict when  or  if it  will recognize revenues  in connection
with any of the foregoing.

In determining the units of accounting, management evaluates  whether  the license has stand-alone

value from the undelivered elements  to  the collaborative  partner based on  the consideration of the
relevant facts and circumstances for each  arrangement.  Factors considered in  this  determination include
the research capabilities of the partner  and the  availability of ADC technology research expertise  in the
general marketplace. If the Company  concludes that  the license has stand-alone value and therefore
will be accounted for as a separate unit  of  accounting, the Company then determines the estimated
selling prices of the license and all other  units  of  accounting based on market conditions, similar
arrangements entered into by third parties, and  entity-specific factors  such as the  terms of the
Company’s previous collaborative agreements, recent preclinical and clinical testing  results of
therapeutic products that use the Company’s ADC technology, the Company’s  pricing practices  and

72

IMMUNOGEN, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

AS OF JUNE 30, 2015

B. Summary of Significant Accounting Policies (Continued)

pricing objectives, the likelihood that  technological  improvements will be made, and,  if made, will be
used by the Company’s collaborators and the nature of the research  services to be performed  on behalf
of its collaborators and market rates for  similar  services.

Upfront payments on development and commercialization licenses are deferred if  facts and
circumstances dictate that the license does not have stand-alone value.  Prior to the adoption of
Accounting Standards Update (ASU) No. 2009-13,  ‘‘Revenue Arrangements  with Multiple
Deliverables’’ on July 1, 2010, the Company determined that its licenses  lacked  stand-alone value and
were combined with other elements of  the arrangement and any amounts associated  with the license
were deferred and amortized over a  certain period, which  the Company  refers  to  as the Company’s
period of substantial involvement. The  determination of the length  of the period over which  to  defer
revenue is subject to judgment and estimation and can  have an impact on the amount of revenue
recognized in a given period. Historically the Company’s  involvement with the development of  a
collaborator’s product candidate has  been significant at the early stages of development, and  lessens as
it progresses into clinical trials. Also, as a drug  candidate gets closer  to  commencing pivotal testing the
Company’s collaborators have sought  an  alternative  site to manufacture their products, as  the
Company’s facility does not produce  pivotal or  commercial drug product.  Accordingly, the Company
generally estimates this period of substantial involvement  to  begin  at the  inception of the collaboration
agreement and conclude at the end of  non-pivotal Phase  II testing.  The Company believes this  period
of substantial involvement is, depending on the nature  of the license,  on  average six and one-half years.
Quarterly, the Company reassesses its  periods of  substantial involvement over which  the Company
amortizes its upfront license fees and  makes  adjustments as appropriate. In the event  a collaborator
elects to discontinue development of a specific product candidate under a development  and
commercialization license, but retains  its  right  to  use the Company’s technology to develop an
alternative product candidate to the same  target  or a target  substitute,  the Company  would cease
amortization of any remaining portion of  the upfront fee until there  is substantial preclinical activity  on
another product candidate and its remaining period of substantial involvement  can be estimated. In the
event that a development and commercialization license were to be terminated, the Company would
recognize as revenue any portion of  the upfront fee that had not previously been recorded  as revenue,
but was classified as deferred revenue,  at the date of such termination.

Subsequent to the  adoption of ASU No. 2009-13, the Company determined that its research
licenses lack stand-alone value and are considered for  aggregation with the  other elements  of  the
arrangement and accounted for as one  unit of accounting.

Upfront payments on development and commercialization licenses may be recognized  upon

delivery of the license if facts and circumstances dictate that  the  license  has stand-alone value from the
undelivered elements, which generally include rights to future  technological improvements, research
services, delivery of cytotoxic agents and the  manufacture of preclinical and  clinical materials.

The Company recognizes revenue related to research services that represent  separate units of
accounting as they are performed, as long as  there is  persuasive evidence  of  an arrangement, the fee is
fixed or determinable, and collection  of the related receivable is probable. The Company  recognizes
revenue related to the rights to future technological improvements over  the estimated term  of the
applicable license.

73

IMMUNOGEN, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

AS OF JUNE 30, 2015

B. Summary of Significant Accounting Policies (Continued)

The Company may also provide cytotoxic agents  to  its collaborators  or  produce preclinical and
clinical materials at negotiated prices which are  generally  consistent with what other third parties  would
charge. The Company recognizes revenue on cytotoxic agents and  on  preclinical and  clinical materials
when the materials have passed all quality  testing required for collaborator acceptance and title and
risk of loss have transferred to the collaborator. Arrangement  consideration allocated  to  the
manufacture of preclinical and clinical  materials in a multiple-deliverable  arrangement  is below the
Company’s full cost, and the Company’s full cost is  not  expected to ever be below  its  contract selling
prices for its existing collaborations. During the fiscal years ended  June 30, 2015, 2014  and 2013,  the
difference between the Company’s full cost to manufacture preclinical and  clinical materials on behalf
of its collaborators as compared to total amounts received from collaborators for the manufacture of
preclinical and clinical materials was $9.2  million, $2.3 million and $755,000,  respectively. The majority
of the Company’s costs to produce these preclinical and clinical materials are  fixed  and then  allocated
to each batch based on the number of batches produced during  the period.  Therefore,  the Company’s
costs to produce these materials are significantly impacted by the number of batches produced during
the period. The volume of preclinical and clinical  materials the Company  produces  is directly related to
the number of clinical trials the Company and its collaborators are preparing  for or  currently  have
underway, the speed of enrollment in  those trials, the  dosage schedule of each clinical trial and the
time period such trials last. Accordingly, the volume of preclinical and clinical materials produced, and
therefore the Company’s per-batch costs to manufacture these preclinical  and clinical materials, may
vary significantly from period to period.

The Company may also produce research material for potential collaborators under  material
transfer agreements. Additionally, the Company performs research activities,  including developing
antibody  specific conjugation processes, on  behalf of its collaborators and potential collaborators during
the early evaluation and preclinical testing stages of drug  development. The Company records amounts
received for research materials produced  or services performed as a component of research and
development support revenue. The Company  also develops conjugation processes  for materials  for later
stage testing and commercialization for  certain collaborators. The Company  is compensated at
negotiated rates and may receive milestone payments  for developing  these processes which are
recorded  as a component of research  and development support revenue.

The Company’s development and commercialization license agreements  have milestone  payments

which  for reporting purposes are aggregated into three categories: (i)  development milestones,
(ii) regulatory milestones, and (iii) sales milestones. Development  milestones are typically  payable when
a product candidate initiates or advances into different clinical trial phases.  Regulatory  milestones are
typically payable upon submission for  marketing approval  with the U.S. Food and Drug Administration,
or FDA, or other countries’ regulatory  authorities or  on receipt of actual  marketing approvals for the
compound or for additional indications. Sales milestones are typically  payable when annual  sales  reach
certain levels.

At the inception of each agreement that includes  milestone payments, the Company evaluates
whether each milestone is substantive  and  at risk to both parties on the  basis of the  contingent nature
of the milestone. This evaluation includes  an assessment of whether (a) the consideration is
commensurate with either (1) the entity’s performance to achieve the milestone, or (2) the
enhancement of the value of the delivered item(s)  as a result of a specific outcome resulting  from the

74

IMMUNOGEN, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

AS OF JUNE 30, 2015

B. Summary of Significant Accounting Policies (Continued)

entity’s performance to achieve the milestone,  (b) the  consideration relates solely to past performance
and (c) the consideration is reasonable relative  to  all  of the deliverables and payment terms  within the
arrangement. The Company evaluates  factors such as  the scientific, regulatory, commercial  and other
risks that must be  overcome to achieve the respective  milestone, the level of effort and investment
required to achieve the respective milestone  and  whether  the milestone consideration  is reasonable
relative to all deliverables and payment terms in the arrangement  in making this assessment.

Non-refundable development and regulatory milestones  that are expected to be achieved as a
result of the Company’s efforts during  the period of substantial involvement are considered substantive
and are recognized as revenue upon  the achievement of the milestone, assuming all other revenue
recognition criteria are met. Milestones  that  are not considered substantive because we do not
contribute effort to the achievement  of  such milestones are generally  achieved after the  period of
substantial involvement and are recognized  as revenue upon  achievement of the  milestone, as  there are
no undelivered elements remaining and  no continuing performance  obligations, assuming  all  other
revenue recognition criteria are met.

Under the Company’s development and commercialization license agreements, the Company

receives royalty payments based upon its  licensees’ net  sales of  covered  products. Generally, under
these agreements the Company is to receive  royalty reports and payments from its licensees
approximately one quarter in arrears, that is, generally in the second  month of the quarter after the
licensee has sold the royalty bearing product or products. The Company recognizes royalty revenues
when it can reliably estimate such amounts  and  collectability is  reasonably assured.  As such, the
Company generally recognizes royalty revenues  in the quarter  reported to the Company  by  its licensees,
or one quarter following the quarter  in which  sales by the  Company’s licensees occurred.

Right-to-Test Agreements

The Company’s right-to-test agreements  provide  collaborators the right  to  (a) test the Company’s

ADC technology for a defined period of time through a  research, or right-to-test, license, (b)  take
options, for a defined period of time, to specified targets  and (c) upon exercise of  those options, secure
or ‘‘take’’ licenses to develop and commercialize  products for the  specified targets on  established terms.
Under these agreements, fees may be  due to the Company (i)  at the inception  of the arrangement
(referred to as ‘‘upfront’’ fees or payments),  (ii) upon taking an option  with respect to a  specific target
(referred to as option fees or payments earned, if any, when the  option is ‘‘taken’’), (iii) upon  the
exercise of a previously taken option  to  acquire a  development and commercialization license(s)
(referred to as exercise fees or payments  earned, if any, when  the development and commercialization
license is ‘‘taken’’), or (iv) some combination of all of these fees.

The accounting for right-to-test agreements is  dependent on the nature  of the options granted to

the collaborative partner. Options are considered  substantive if,  at the  inception of a right-to-test
agreement, the Company is at risk as  to  whether the  collaborative partner will  choose  to  exercise  the
options to secure development and commercialization licenses. Factors that are considered  in evaluating
whether options are substantive include the  overall  objective of the arrangement,  the benefit the
collaborator might obtain from the agreement without  exercising the  options, the  cost to exercise the
options relative to the total upfront consideration, and the  additional financial commitments or
economic penalties imposed on the collaborator as a  result of  exercising the options.

75

IMMUNOGEN, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

AS OF JUNE 30, 2015

B. Summary of Significant Accounting Policies (Continued)

For right-to-test agreements where the options to secure development and commercialization
licenses to the Company’s ADC technology are  considered substantive, the  Company does not consider
the development and commercialization licenses to be a  deliverable  at  the inception of the  agreement.
For those right-to-test agreements entered into prior  to  the adoption of ASU No. 2009-13 where the
options to secure development and commercialization licenses are considered substantive, the Company
has deferred the upfront payments received and recognizes this  revenue  over the period during which
the collaborator could elect to take options for development  and  commercialization  licenses.  These
periods are specific to each collaboration  agreement. If a collaborator takes an option to acquire  a
development and commercialization license under  these agreements, any substantive  option fee is
deferred and recognized over the life  of the option, generally 12 to 18  months. If a collaborator
exercises an option and takes a development and commercialization license to a specific target, the
Company attributes the exercise fee to the development and commercialization  license. Upon exercise
of an option to acquire a development  and commercialization license, the Company would also
attribute any remaining deferred option  fee to the development  and commercialization license  and
apply  the multiple-element revenue recognition criteria to  the  development and  commercialization
license and any other deliverables to  determine the  appropriate revenue recognition, which  will  be
consistent with the Company’s accounting policy  for upfront payments  on single-target licenses. In the
event a right-to-test agreement were  to  be terminated, the Company would recognize as  revenue any
portion of the upfront fee that had not  previously  been recorded as  revenue, but was classified as
deferred revenue, at the date of such  termination. None  of the Company’s  right-to-test  agreements
entered into subsequent to the adoption  of ASU  No. 2009-13  has been determined  to  contain
substantive options.

For right-to-test agreements where the options to secure development and commercialization
licenses to the Company’s ADC technology are  not  considered substantive, the Company considers the
development and commercialization licenses to be a deliverable at the  inception of the agreement  and
applies the multiple-element revenue recognition criteria to  determine the appropriate revenue
recognition. None of the Company’s right-to-test  agreements entered  into  prior to the adoption of ASU
No. 2009-13 has been determined to  contain non-substantive options.

The Company does not directly control when or if any collaborator will exercise its options for
development and commercialization licenses. As  a result, the  Company cannot predict  when or if it will
recognize revenues in connection with any of the  foregoing.

Inventory

Inventory costs relate to clinical trial materials being manufactured for sale to the Company’s

collaborators. Inventory is stated at the lower of cost or market  as determined on  a first-in,  first-out
(FIFO) basis.

76

IMMUNOGEN, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

AS OF JUNE 30, 2015

B. Summary of Significant Accounting Policies (Continued)

Inventory at June 30, 2015 and 2014  is summarized below (in thousands):

Raw materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Work in process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

$ 279
2,656

$ 437
2,513

Total . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

$2,935

$2,950

June 30,

2015

2014

Raw materials inventory consists entirely of DM1 and  DM4, proprietary cell-killing agents  the
Company developed as part of its ADC technology. All raw materials inventory is currently  procured
from a single supplier.

Work in process inventory consists of  conjugate manufactured for  sale to the  Company’s

collaborators to be used in preclinical and clinical studies.  All conjugate is made  to  order at the request
of the collaborators and subject to the  terms and  conditions of respective  supply agreements. As such,
no excess reserve for work in process inventory is required.

Raw materials inventory cost is stated  net of write-downs of $1.4  million  and $661,000  as of

June 30, 2015 and June 30, 2014, respectively. The  write-downs represent the cost  of  raw materials that
the Company considers to be in excess of a twelve-month supply based on firm, fixed orders and
projections from its collaborators as  of  the respective balance  sheet date.

Due to yield fluctuations, the actual amount of  raw materials that will  be  produced in future
periods under third-party supply agreements is  highly uncertain. As such, the amount of  raw materials
produced could be more than is required to support the development  of the Company’s collaborators’
product  candidates. Such excess supply, as determined  under the Company’s inventory reserve policy, is
charged to research and development  expense.

The Company produces preclinical and clinical materials for its  collaborators either in  anticipation

of or in support of preclinical studies  and  clinical trials, or for process  development and analytical
purposes. Under the terms of supply  agreements with its collaborators, the Company generally receives
rolling six-month firm, fixed orders for  conjugate  that the Company  is required  to  manufacture, and
rolling twelve-month manufacturing projections for  the quantity  of conjugate the  collaborator expects to
need in any given twelve-month period. The amount of clinical  material produced is  directly related to
the number of collaborator anticipated or  on-going clinical trials  for which the Company is producing
clinical material, the speed of enrollment  in  those trials, the  dosage schedule of each clinical trial and
the time period, if any, during which patients in the  trial receive clinical benefit from  the clinical
materials. Because these elements are difficult to estimate  over the course of a  trial,  substantial
differences between collaborators’ actual manufacturing orders and their projections could result in the
Company’s usage of raw materials varying  significantly  from estimated usage  at an earlier reporting
period. To the extent that a collaborator  has provided the Company  with a firm, fixed order, the
collaborator is required by contract to  reimburse  the Company the  full  negotiated  price of the
conjugate, even if the collaborator subsequently cancels the manufacturing run.

77

IMMUNOGEN, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

AS OF JUNE 30, 2015

B. Summary of Significant Accounting Policies (Continued)

The Company capitalizes raw material  as inventory upon receipt and accounts for the raw material

inventory as follows:

a)

b)

c)

to the extent that the Company  has up to twelve months  of  firm, fixed  orders  and/or
projections from its collaborators, the Company capitalizes  the  value  of raw materials  that  will
be used in the production of conjugate subject to these firm, fixed orders and/or  projections;

the Company considers more than a  twelve  month supply of  raw materials that is not
supported by firm, fixed orders and/or  projections  from its collaborators to be excess and
establishes a reserve to reduce to zero the value of any  such excess raw material inventory
with a corresponding charge to research  and  development expense; and

the Company also considers any other external factors and  information of which it  becomes
aware and assesses the impact of such factors or information on  the net realizable value of the
raw  material inventory at each reporting period.

During  fiscal years 2015, 2014 and 2013,  the Company obtained  additional amounts of DMx from
its  supplier which yielded more material  than would be required by  the Company’s collaborators  over
the next twelve months and as a result, the Company  recorded $1.0 million, $364,000 and $798,000,
respectively, of charges to research and  development expense  related to raw  material  inventory
identified as excess. Increases in the Company’s  on-hand supply of raw materials,  or a reduction to the
Company’s collaborators’ projections, could result in significant changes  in the Company’s  estimate of
the net realizable value of such raw material inventory. Reductions in collaborators’ projections could
indicate that the Company has excess raw  material inventory and the Company would then evaluate the
need to record write-downs as charges to research and development expense.

Unbilled Revenue

The majority of the Company’s unbilled revenue at June  30, 2015 and 2014  represents research

funding earned based on actual resources  utilized  under the Company’s various collaborator
agreements.

Other Accrued Liabilities

Other accrued liabilities consisted of  the following at June  30, 2015 and 2014  (in  thousands):

Accrued contract payments . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Accrued clinical trial costs . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Accrued professional services . . . . . . . . . . . . . . . . . . . . . . . . . . .
Accrued employee benefits . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Accrued public reporting charges . . . . . . . . . . . . . . . . . . . . . . . .
Other current accrued liabilities . . . . . . . . . . . . . . . . . . . . . . . . .

June 30,

2015

2014

$ 5,830
1,735
788
567
192
1,329

$2,914
1,778
833
454
183
506

Total . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

$10,441

$6,668

78

IMMUNOGEN, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

AS OF JUNE 30, 2015

B. Summary of Significant Accounting Policies (Continued)

Research and Development Expenses

The Company’s research and development expenses are  charged  to  expense as incurred and relate

to (i) research to evaluate new targets  and to develop and evaluate new antibodies, linkers and
cytotoxic agents, (ii) preclinical testing of  its own and, in  certain instances,  its collaborators’ product
candidates, and the cost of its own clinical trials, (iii) development related to clinical and  commercial
manufacturing processes and (iv) manufacturing operations which  also include raw materials. Payments
made by the Company in advance for research  and development  services not yet  provided and/or
materials not yet delivered and accepted  are recorded as prepaid expenses and are included in the
accompanying Consolidated Balance  Sheets as  prepaid  and  other current assets.

Income Taxes

The Company uses the liability method  to  account for income taxes. Deferred  tax assets and
liabilities are determined based on differences between the  financial  reporting and income tax  basis of
assets and liabilities, as well as net operating loss  carry forwards  and tax credits and are measured using
the enacted tax rates and laws that will be in effect  when the  differences  reverse. A valuation allowance
against net deferred tax assets is recorded if, based  on the available  evidence, it  is more likely than  not
that some or all of the deferred tax assets  will not be realized.

Financial Instruments and Concentration of Credit  Risk

Cash and cash equivalents are primarily maintained with  three financial institutions in the  U.S.

Deposits with banks may exceed the amount of insurance provided on such deposits.  Generally,  these
deposits may be redeemed upon demand  and,  therefore, bear minimal  risk. The  Company’s cash
equivalents consist of money market funds with underlying investments  primarily being U.S.
Government-issued securities and high  quality, short-term  commercial paper. Financial instruments that
potentially subject the Company to concentrations  of credit  risk consist principally  of  cash, cash
equivalents and marketable securities.  The Company held no  marketable securities  as of June 30, 2015.
The Company’s investment policy, approved by the Board  of Directors,  limits the amount it may invest
in any one type of investment, thereby  reducing credit  risk  concentrations.

Derivative instruments include a portfolio  of  short  duration foreign  currency  forward contracts
intended to mitigate the risk of exchange  fluctuations for existing or anticipated receivable  and payable
balances denominated in foreign currency. Derivatives are  recorded at fair value  and classified  as other
current assets or liabilities. The fair value  of these  instruments  represents  the present value  of
estimated future cash flows under the  contracts, which are a function of underlying interest rates,
currency rates, related volatility, counterparty creditworthiness and duration of  the contracts.  Changes
in these factors or a combination thereof  may affect  the fair  value of these instruments.

79

IMMUNOGEN, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

AS OF JUNE 30, 2015

B. Summary of Significant Accounting Policies (Continued)

The Company does not designate foreign  currency  forward contracts  as hedges for  accounting
purposes, and changes in the fair value of  these instruments are recognized in  earnings during the
period of change. Because the Company  enters into forward contracts  only as an  economic hedge, any
gain or loss on the underlying foreign-denominated existing  or  anticipated  receivable or payable
balance would be offset by the loss or  gain on the forward contract.  Net gains on forward  contracts for
the years ended June 30, 2014 and 2013  were $2,000 and $197,000, respectively, and are included in the
accompanying Consolidated Statement  of  Operations  as other (expense) income, net. As of June 30,
2015 and 2014, the Company had no  outstanding forward  contracts.  The  Company does not anticipate
using derivative instruments for any purpose other  than hedging  exchange  rate exposure.

Cash and Cash Equivalents

All highly liquid financial instruments with maturities of three months or less when  purchased are
considered cash equivalents. As of June  30, 2015 and June 30, 2014, the Company  held $278.1 million
and $142.3 million, respectively, in cash  and money market  funds consisting principally of  U.S.
Government-issued securities and high  quality, short-term  commercial paper which were  classified as
cash and cash equivalents.

Fair Value of Financial Instruments

ASC Topic 820 defines fair value, establishes  a framework for  measuring  fair value  in accordance

with accounting principles generally accepted in the U.S., and  expands disclosures about fair value
measurements. Fair value is defined under  ASC  Topic 820 as  the  exchange  price that would be received
for an asset or paid to transfer a liability (an exit  price) in the principal or  most advantageous market
for the asset or liability in an orderly  transaction between market participants on the measurement
date.  Valuation techniques used to measure fair value  must  maximize the use  of observable  inputs  and
minimize the use of unobservable inputs.  The standard describes a fair value hierarchy to measure fair
value which is based on three levels of  inputs, of which  the first two are considered observable and  the
last unobservable, as follows:

(cid:129) Level 1—Quoted prices in active markets  for  identical  assets  or liabilities.

(cid:129) Level 2—Inputs other than Level 1  that are observable, either  directly or  indirectly, such as
quoted prices for similar assets or liabilities; quoted  prices in  markets that  are not active; or
other inputs that are observable or can be corroborated by observable market data for
substantially the full term of the assets  or liabilities.

(cid:129) Level 3—Unobservable inputs that  are supported by little or no  market  activity and that are

significant to the fair value of the assets or liabilities.

80

IMMUNOGEN, INC.

NOTES TO CONSOLIDATED FINANCIAL  STATEMENTS (Continued)

AS OF JUNE 30, 2015

B. Summary of Significant Accounting Policies  (Continued)

As of June 30, 2015, the Company held  certain assets that are required to be measured  at fair

value on  a recurring basis. The following  table  represents the fair  value hierarchy for the Company’s
financial assets measured at fair value on a recurring basis as of  June  30, 2015 (in thousands):

Fair Value Measurements at June 30, 2015 Using

Quoted Prices in
Active Markets for
Identical Assets

Significant Other
Observable Inputs

Significant
Unobservable
Inputs

Total

(Level 1)

(Level 2)

(Level 3)

Cash and cash equivalents . . . . . . . . . . . . .

$278,109

$278,109

$—

$—

As of June 30, 2014, the Company held  certain assets that are required to be measured  at fair

value on  a recurring basis. The following  table  represents the fair  value hierarchy for the Company’s
financial assets measured at fair value on a recurring basis as of  June  30, 2014 (in thousands):

Fair Value Measurements at June 30, 2014 Using

Quoted Prices in
Active Markets for
Identical Assets

Significant Other
Observable Inputs

Significant
Unobservable
Inputs

Total

(Level 1)

(Level 2)

(Level 3)

Cash and cash equivalents . . . . . . . . . . . . .

$142,261

$142,261

$—

$—

The fair value of the Company’s cash equivalents is  based primarily on quoted  prices from active

markets.

The carrying amounts reflected in the consolidated  balance sheets for accounts  receivable, unbilled
revenue, prepaid and other current assets, accounts payable, accrued compensation,  and other accrued
liabilities approximate fair value due  to  their short-term  nature.

Property and Equipment

Property and equipment are stated at cost. The Company provides for depreciation  based upon

expected useful lives using the straight-line method  over the  following  estimated useful lives:

Machinery and equipment . . . . . . . . . .
Computer hardware and software . . . . .
Furniture and fixtures . . . . . . . . . . . . .
Leasehold improvements . . . . . . . . . . .

5 years
3 years
5 years
Shorter of remaining lease term or 7 years

Equipment under capital leases is amortized over  the lives  of  the respective  leases or the estimated

useful lives of the assets, whichever is shorter, and included in  depreciation  expense.

Maintenance and repairs are charged to expense as incurred. Upon retirement or sale, the cost  of

disposed assets and the related accumulated  depreciation  are  removed from  the accounts and any
resulting gain or loss is included in the statement of operations.  The  Company recorded $(7,000),
$(20,000) and $21,000 of (losses) gains on the sale/disposal of certain  furniture and equipment during
the years ended June 30, 2015, 2014,  and  2013, respectively.

81

IMMUNOGEN, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

AS OF JUNE 30, 2015

B. Summary of Significant Accounting Policies (Continued)

Impairment of Long-Lived Assets

In accordance with ASC Topic 360, ‘‘Property,  Plant, and  Equipment,’’  the Company continually
evaluates whether events or circumstances have occurred that indicate  that  the estimated remaining
useful life of its long-lived assets may warrant  revision or  that the carrying value of these assets  may be
impaired. The Company evaluates the realizability  of its  long-lived assets  based on cash  flow
expectations for the related asset. Any write-downs are  treated as permanent  reductions in  the carrying
amount of the assets. Based on this evaluation, the Company believes that, as of  each  of the balance
sheet dates presented, none of the Company’s long-lived assets were impaired.

Computation of Net Loss per Common Share

Basic and diluted net loss per share is  calculated based upon  the weighted average number of

common shares outstanding during the period. During periods of income, participating securities  are
allocated a proportional share of income  determined  by dividing total weighted  average participating
securities by the sum of the total weighted  average common shares and  participating  securities (the
‘‘two-class method’’). Shares of the Company’s  restricted stock participate in any  dividends  that  may be
declared by the Company and are therefore considered  to  be  participating  securities. Participating
securities have the effect of diluting both basic and diluted earnings per share  during periods  of
income. During periods of loss, no loss is  allocated to participating securities  since they  have no
contractual obligation to share in the losses  of  the Company.  Diluted  (loss) income per share is
computed after giving consideration  to  the  dilutive effect  of stock  options  that  are outstanding  during
the period, except where such non-participating  securities would be anti-dilutive.

The Company’s common stock equivalents,  as calculated  in accordance with  the treasury-stock

method, are shown in the following table  (in thousands):

June 30,

2015

2014

2013

Options outstanding to purchase common stock and unvested
restricted stock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Common stock equivalents under treasury stock method . . . .

9,739
770

8,486
1,820

7,703
2,149

The Company’s common stock equivalents  have not been included in the  net loss  per  share

calculation because their effect is anti-dilutive  due  to  the Company’s net  loss position.

Stock-based Compensation

As of June 30, 2015, the Company is  authorized to grant future awards under one employee  share-

based compensation plan, which is the  ImmunoGen, Inc.  2006 Employee, Director and Consultant
Equity Incentive Plan, or the 2006 Plan.  At the annual meeting of  shareholders on November 11, 2014,
an amendment to  the 2006 Plan was approved and an  additional 5,500,000  shares were authorized  for
issuance under this plan. As amended, the 2006  Plan  provides  for the issuance of Stock  Grants, the
grant of Options and the grant of Stock-Based Awards for up  to  17,500,000 shares of  the Company’s
common stock, as well as 1,676,599 shares  of common  stock  which represent awards  granted under the
previous stock option plan, the ImmunoGen, Inc.  Restated  Stock Option  Plan, or  the Former  Plan,  that

82

IMMUNOGEN, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

AS OF JUNE 30, 2015

B. Summary of Significant Accounting Policies (Continued)

were forfeited, expired or were cancelled  without delivery of shares of common  stock or which  resulted
in the forfeiture of shares of common stock back to the  Company between November 11, 2006  and
June 30, 2014. Option awards are granted  with an  exercise price equal to the  market  price of the
Company’s stock at the date of grant. Options vest at  various periods of up to four years and  may be
exercised within ten years of the date  of grant.

The stock-based awards are accounted  for under ASC  Topic  718, ‘‘Compensation—Stock

Compensation.’’ Pursuant to Topic 718, the estimated grant  date fair value  of  awards is charged  to  the
statement of operations over the requisite  service  period, which is the  vesting period. Such amounts
have been reduced by an estimate of  forfeitures  of all unvested  awards. The fair value of each stock
option is estimated on the date of grant  using the  Black-Scholes option-pricing model with the
weighted average assumptions noted  in  the following table. As the Company has not paid dividends
since inception, nor does it expect to pay any dividends  for  the foreseeable  future, the  expected
dividend yield assumption is zero. Expected volatility is based  exclusively on historical  volatility  data  of
the Company’s stock. The expected term of stock options granted is  based exclusively  on historical data
and represents the period of time that stock  options  granted  are  expected to be outstanding.  The
expected term is calculated for and applied to one  group of stock options as the  Company does not
expect substantially different exercise or  post-vesting  termination  behavior amongst its employee
population. The risk-free rate of the stock  options  is based  on the U.S. Treasury rate  in effect at the
time of grant for the expected term of the  stock  options.

Year Ended June 30,

2015

2014

2013

Dividend . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . None
Volatility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Risk-free interest rate . . . . . . . . . . . . . . . . . . . . . . . . . . .
Expected life (years) . . . . . . . . . . . . . . . . . . . . . . . . . . . .

60.86% 60.44% 60.44%
1.84% 1.74% 0.87%
6.3
6.3

6.3

None

None

Using the Black-Scholes option-pricing  model, the  weighted average grant  date fair  values  of

options granted during fiscal years 2015,  2014 and 2013 were  $6.04, $10.50,  and $8.60  per  share,
respectively.

83

IMMUNOGEN, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

AS OF JUNE 30, 2015

B. Summary of Significant Accounting Policies (Continued)

A summary of option activity under the  2006 Plan as of  June 30, 2015, and changes during the

twelve month period then ended is presented below (in thousands, except weighted-average data):

Number of
Stock
Options

Weighted- Weighted-
Average
Average
Remaining
Exercise
Life in Yrs
Price

Aggregate
Intrinsic
Value

Outstanding at June 30, 2014 . . . . . . . . .
Granted . . . . . . . . . . . . . . . . . . . . . . . .
Exercised . . . . . . . . . . . . . . . . . . . . . . .
Forfeited/Canceled . . . . . . . . . . . . . . . . .

8,449
2,743
(651)
(852)

Outstanding at June 30, 2015 . . . . . . . . .

9,689

Outstanding at June 30, 2015—vested  or

unvested and expected to vest . . . . . . .

Exercisable at June 30, 2015 . . . . . . . . . .

9,432

5,380

$12.93
$10.38
$ 6.81
$14.42

$12.49

$12.50

$11.89

6.78

$28,260

6.72

5.31

$27,446

$17,939

In November 2012 and January 2015,  the Company granted two officers of the  Company 50,000
and 25,000 shares of restricted stock,  respectively, upon  hire. Pursuant  to  the agreements, the shares
vest ratably in annual installments over  the subsequent four  years.  The fair value of the restricted stock
was determined by the closing price  on the  date of grant. A summary of restricted stock activity under
the 2006 Plan as of June 30, 2015, and  changes during the twelve month  period then  ended is
presented below (in thousands, except weighted-average data):

Unvested at June 30, 2014 . . . . . . . . . . . . . . . . . . . . . . . . . .
Awarded . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Vested . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

37,500
25,000
(12,500)

Unvested at June 30, 2015 . . . . . . . . . . . . . . . . . . . . . . . . . .

50,000

Number of
Restricted
Stock Shares

Weighted-
Average
Exercise
Price

$11.93
$ 6.53
$11.93

$ 9.23

Stock compensation expense related to stock  options and restricted stock  awards  granted under  the

2006 Plan was $15.3 million, $15.6 million  and $12.4  million  during  the fiscal years ended  June 30,
2015, 2014, and 2013, respectively. As  of June 30, 2015,  the estimated fair value of unvested  employee
awards was approximately $19.5 million, net of estimated forfeitures.  The  weighted-average remaining
vesting period for these awards is approximately  two years.

84

IMMUNOGEN, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

AS OF JUNE 30, 2015

B. Summary of Significant Accounting Policies (Continued)

A summary of option activity for options vested during the fiscal years ended June 30, 2015,  2014

and 2013 is presented below (in thousands):

Total fair value of options vested . . . . . . . . . . . . . . . . .
Total intrinsic value of options exercised . . . . . . . . . . . .
Cash received for exercise of stock options . . . . . . . . . .

$16,145
3,275
4,429

$12,535
9,961
9,136

$9,670
6,737
4,026

Year Ended June 30,

2015

2014

2013

Comprehensive Loss

The Company presents comprehensive loss  in accordance with ASC Topic 220, Comprehensive
Income. Comprehensive loss is comprised of the  Company’s  net loss  for the  years  ended June 30, 2015,
2014 and 2013.

Segment Information

During  the three fiscal years ended June 30, 2015,  the Company continued to operate in  one
reportable business segment under the management approach of ASC Topic 280, Segment Reporting,
which  is the business of discovery of monoclonal antibody-based anticancer therapeutics.

The percentages of revenues recognized from  significant customers of  the  Company in  the years

ended June 30, 2015, 2014 and 2013  are  included in  the following table:

Collaborative Partner:

Year Ended
June 30,

2015

2014

2013

Lilly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Novartis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Roche . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

21% 18% 2%
43% 38% 49%
23% 34% 30%

There were no other customers of the Company  with significant revenues  in the years ended

June 30, 2015, 2014 and 2013.

Recent Accounting Pronouncements

In May 2014, the FASB issued Accounting Standards Update  2014-9, Revenue from Contracts with
Customers (Topic 606) (‘‘ASU 2014-09’’), to clarify the principles for recognizing  revenue. This update
provides a comprehensive new revenue  recognition model that  requires revenue to be recognized in  a
manner to depict the transfer of goods or services  to  a customer at an amount that reflects the
consideration expected to be received  in exchange for  those goods or services. The original effective
date  would have required the Company to adopt beginning in  its  first quarter of  fiscal  2018. In July
2015, the FASB voted to amend ASU  2014-09 by  approving a one-year deferral  of  the effective date  as
well as providing the option to early  adopt the standard on the original effective  date. Accordingly, the
Company may adopt the standard in either  its first quarter of  fiscal  2018 or  2019. The new  revenue
standard allows for either full retrospective or modified retrospective application. The Company is

85

IMMUNOGEN, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

AS OF JUNE 30, 2015

B. Summary of Significant Accounting Policies (Continued)

currently evaluating the timing of its adoption and the  impact that this guidance  will  have on its
consolidated financial statements and related disclosures.

In August 2014, the FASB issued Accounting Standards  Update  2014-15, Presentation of Financial

Statements-Going Concern (Subtopic 205-40): Disclosure of  Uncertainties about  an  Entity’s Ability to
Continue as a Going Concern. This new standard gives a company’s  management  the final
responsibilities to decide whether there’s  substantial doubt  about the  company’s ability to continue  as a
going concern and to provide related footnote  disclosures. The standard provides  guidance to
management, with principles and definitions that are  intended to reduce  diversity in  the timing and
content of disclosures that companies  commonly  provide  in their footnotes. Under the new standard,
management must decide whether there  are conditions or  events, considered  in the aggregate, 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,  or within one  year after the date that the financial
statements are available to be issued  when applicable. This guidance is effective for annual reporting
beginning after December 15, 2016, including interim periods  within the year of adoption,  with early
application permitted. Accordingly, the standard is effective for the Company on July 1, 2017.  The
adoption of this guidance is not expected to have  a material impact on  the Company’s  consolidated
financial statements.

In April 2015, the FASB issued Accounting  Standards Update 2015-03, Interest-Imputation  of
Interest (Subtopic 835-30): Simplifying the  Presentation of  Debt Issuance Costs. To simplify presentation of
debt issuance costs, this new standard requires that debt issuance costs  related to a recognized debt
liability be presented in the balance sheet  as a  direct  deduction from the  carrying amount of that debt
liability, consistent with debt discounts. The recognition and measurement guidance  for debt issuance
costs are not affected by this update. This  guidance is effective  for annual reporting beginning after
December 15, 2015, including interim  periods within  the year of adoption, and calls for retrospective
application, with early application permitted. Accordingly, the standard  is effective for the Company  on
July 1, 2016. The Company is currently evaluating the  impact that this guidance  will  have on the
Company’s consolidated financial statements.

In July 2015, the FASB issued Accounting Standards  Update 2015-11, Simplifying the Measurement
of Inventory (Topic 330). To simplify the principles for subsequent measurement of inventory, this  new
standard requires inventory measured  using any method other than LIFO or  the retail method shall be
measured at the lower of cost and net realizable value,  rather than lower  of  cost or market. This
guidance is effective for annual reporting  beginning  after December 15, 2016,  including interim  periods
within the year of  adoption, and calls  for prospective application, with early application permitted.
Accordingly, the standard is effective  for  the Company  on July 1, 2017.  The adoption of this guidance
is not expected to have a material impact  on the Company’s consolidated financial  statements.

C. Agreements

Significant Collaborative Agreements

Roche

In May 2000, the Company granted Genentech, now a unit  of Roche, an  exclusive  license to use
the Company’s maytansinoid ADC technology with antibodies, such  as trastuzumab, or other  proteins

86

IMMUNOGEN, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

AS OF JUNE 30, 2015

C. Agreements (Continued)

that target HER2. Under the terms of this  agreement, Roche has exclusive worldwide rights to develop
and commercialize maytansinoid ADC compounds  targeting HER2. In  February 2013, the US FDA
granted marketing approval to the HER2-targeting ADC  compound, Kadcyla. Roche received
marketing approval for Kadcyla in Japan and  in the European Union (EU) in September 2013  and
November 2013, respectively. They have  also  received  marketing  approval in  various other countries
around the world. Roche is responsible for the manufacturing, product development and  marketing  of
any products  resulting from the agreement.  The  Company is  compensated for any preclinical and
clinical materials that the Company manufactures under  the agreement. The Company received  a
$2 million non-refundable upfront payment from  Roche upon execution of the  agreement. The
Company is also entitled to receive up to a  total of $44  million in  milestone payments, plus royalties on
the commercial sales of Kadcyla or any  other resulting  products. Total  milestones are categorized as
follows: development milestones—$13.5 million; and regulatory milestones—$30.5 million. Through
June 30, 2015, the  Company has received and recognized $13.5 million and $20.5 million in
development and regulatory milestone payments, respectively, related to Kadcyla. The US marketing
approval of Kadcyla in February 2013 triggered  a $10.5 million regulatory milestone payment to the
Company, which is included in license and  milestone fees for the fiscal year ended  June  30, 2013. The
Company received two $5 million regulatory  milestone payments in connection  with marketing approval
of Kadcyla in Japan and in the EU, which is included in  license  and milestone  fees  for the  fiscal  year
ended June 30, 2014. Based on an evaluation of the  effort contributed to the achievement of these
milestones in fiscal years 2014 and 2013, the  Company determined these milestones were  not
substantive. In consideration that there were no undelivered elements remaining, no  continuing
performance obligations and all other revenue recognition criteria had been  met, the  Company
recognized the non-refundable payments as revenue upon achievement of  the milestones. The  next
potential milestone the Company will be entitled to receive  will be a $5 million regulatory milestone for
marketing approval of Kadcyla for a first  extended indication as defined in  the agreement. Based on an
evaluation of the effort contributed towards the achievement of this  future  milestone, the Company
determined this milestone is not substantive.

The Company receives royalty reports  and payments related  to  sales of  Kadcyla from Roche one
quarter in arrears. In accordance with  our  revenue recognition policy, $13.9 million of royalties on net
sales of Kadcyla for the nine-month  period  ended December  31, 2014 were recorded  and included in
royalty revenue for the year ended June 30, 2015  compared to $10.3 million of royalties on  net sales  of
Kadcyla for the twelve- month period  ended  March 31, 2014 recorded and included  in royalty revenue
for the year ended June 30, 2014. The Company recorded $592,000  of royalties  on net sales of Kadcyla
for the three-month period ended March  31, 2013 in  its  fourth quarter  of  fiscal 2013. Total revenues for
the year ended June 30, 2015 also include  $5.5 million  of non-cash  royalty revenue on net  sales  of
Kadcyla for the three-month period ended  March 31, 2015 as royalties  on Kadcyla sales  occurring after
January 1, 2015 are covered by a royalty  purchase  agreement whereby the  associated cash is remitted to
Immunity Royalty Holdings, L.P, or IRH, as  discussed further in Note  E

Roche, through its Genentech unit, also  has licenses for the exclusive right  to  use the Company’s
maytansinoid ADC technology with antibodies to four undisclosed targets, which were  granted under
the terms of a separate May 2000 right-to-test  agreement with  Genentech. For  each of these licenses
the Company received a $1 million license  fee and is  entitled to receive up to a total of  $38 million in
milestone payments and also royalties on  the sales of any resulting  products. The total  milestones are

87

IMMUNOGEN, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

AS OF JUNE 30, 2015

C. Agreements (Continued)

categorized as follows: development milestones—$8 million; regulatory milestones—$20 million; and
sales milestones—$10 million. The Company has not received any milestone payments  from these
agreements through June 30, 2015. Roche is responsible  for the development, manufacturing, and
marketing of any products resulting from  these licenses.  The next potential milestone the Company  will
be entitled to receive under any of these agreements  will be a development milestone for filing of an
IND application which will result in a $1  million payment being due. At  the time  of execution of each
of these  development and commercialization licenses, there  was  significant uncertainty as to whether
this  milestone would be achieved. In consideration of this, as well as the  Company’s past  involvement
in the research and manufacturing these  products, this  milestone was deemed substantive. Roche no
longer has the right to take additional  licenses under the  right-to-test agreement. The Company
received non-refundable technology access fees totaling $5 million  for  the eight-year term  of the
right-to-test agreement. The upfront fees were deferred and recognized  ratably over the  period during
which  Genentech could elect to obtain product  licenses.

Amgen

Under a now-expired right-to-test agreement, in September  2009, November 2009 and  December

2012, Amgen took three exclusive development and commercialization licenses, for which  the Company
received an exercise fee of $1 million for  each license taken. In May 2013, Amgen  took one
non-exclusive development and commercialization license, for which the  Company received an exercise
fee of $500,000. In October 2013, the non-exclusive license was amended and  converted  to  an exclusive
license, for which Amgen paid an additional  $500,000 fee to the Company.  Amgen has sublicensed  its
rights under this license to Oxford BioTherapeutics Ltd. For each development  and commercialization
license taken, the Company is entitled to receive up to a total of $34  million  in milestone  payments,
plus royalties on the commercial sales  of  any  resulting products.  The total milestones  per  license are
categorized as follows: development milestones—$9 million; regulatory milestones—$20 million; and
sales milestones—$5 million. Amgen  (or  its sublicensee(s)) is  responsible  for the  manufacturing,
product  development and marketing  of any products  resulting from these development and
commercialization licenses.

Since a deliverable to the original right-to-test agreement  was determined to be materially
modified at the time the non-exclusive  license  was  converted to exclusive in October 2013, the
Company accounted for the multiple-element agreement in  accordance with ACS 605-25 (as amended
by ASU No. 2009-13). As a result, all of the deferred  revenue  recorded on the  date of the  modification
and the new consideration received as  part of the modification was allocated to all of  the remaining
deliverables at the time of amendment of the right-to-test  agreement  based on the estimated selling
price of each element. The remaining amount represents consideration  for  previously delivered
elements and was recognized upon the  execution of the  modification.

The outstanding licenses, including the exclusive license delivered upon the  signing of the
amendment, contain the rights to future  technological improvements as well as options  to  purchase
materials and research and development  services. The Company  concluded  that  additional materials
and research and development services would be paid at a contractual  price  equal to the estimated
selling price based estimated prices that would be charged  by third parties  for similar  services. The
estimated selling price of the right to  technological improvements is the Company’s best estimate of

88

IMMUNOGEN, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

AS OF JUNE 30, 2015

C. Agreements (Continued)

selling price and was determined by estimating the probability that  technological improvements will  be
made and the probability that such technological  improvements  made will be used by Amgen.  In
estimating these probabilities, we considered  factors such as the technology that is the  subject of the
development and commercialization licenses, our history of making technological improvements,  and
when such improvements, if any, were likely to occur  relative  to  the  stage of development of  any
product  candidates pursuant to the development and commercialization  licenses.  The  Company’s
estimate of probability considered the  likely  period of time that  any improvements would be utilized,
which  was estimated to be ten years following delivery of a  commercialization and development license.
The value of any technological improvements  made available after this ten year  period was  considered
to be de minimis due to the significant additional costs  that would be incurred to incorporate such
technology into any existing product candidates.  The estimate  of  probability was multiplied by the
estimated selling price of the development  and commercialization licenses  and the  resulting cash flow
was discounted at a rate of 13%, representing the Company’s  estimate of its cost  of capital at  the time
of amendment of the right-to-test agreement.

The $430,000 determined to be the estimated selling  price of the future technological

improvements is being recognized as  revenue ratably  over the period  the Company  is obligated to make
available any technological improvements,  which is equivalent to the estimated term  of  the agreement.
The Company estimates the term of  a development and commercialization  license to be approximately
25 years, which reflects management’s  estimate of the  time necessary to develop and commercialize
products pursuant to the license plus the  estimated royalty term. The Company reassesses the  estimated
term at the end of each reporting period.

After accounting for the undelivered  elements at  the estimated selling  price, the Company  had
$2.2 million of remaining allocable consideration which was determined  to represent  consideration for
the previously delivered elements, including the exclusive license that was delivered upon the execution
of the modification. This amount was  recorded  as revenue  and is included  in license  and milestone fees
for the year ended June 30, 2014.

In November 2011, the IND applications to the FDA  for two compounds developed under the
2009 development and commercialization licenses became effective, which triggered two  $1 million
milestone payments to the Company. The  next potential milestone  the Company will be entitled  to
receive under the 2009 development and  commercialization licenses  will be  a development milestone
for the first dosing of a patient in a Phase II clinical trial, which will result in a $3 million payment
being due. The next potential milestones  the Company  will be entitled  to receive under the December
2012 and May 2013 development and commercialization licenses will be a $1 million  development
milestone for an IND becoming effective. At the time  of execution of each of  these development and
commercialization licenses, there was  significant uncertainty  as to whether these milestones would be
achieved. In consideration of this, as  well  as the Company’s  past  involvement in the research and
manufacturing of these product candidates, these  milestones were  deemed substantive.

Costs directly attributable to the Amgen collaborative agreement are comprised of compensation
and benefits related to employees who provided research and development services  on behalf of  Amgen
as well as costs of  clinical materials sold. Indirect  costs are  not  identified to individual collaborators.
The costs related to the research and  development  services  amounted to  approximately $62,000,
$179,000 and $174,000 for fiscal years  2015,  2014 and  2013, respectively. The costs  related to clinical

89

IMMUNOGEN, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

AS OF JUNE 30, 2015

C. Agreements (Continued)

materials sold were approximately $664,000 and $670,000 for  fiscal years 2014 and 2013,  respectively.
There were no similar costs recorded in  fiscal year 2015.

Sanofi

In July 2003, the Company entered into a broad collaboration agreement  with Sanofi  (formerly
Aventis) to discover, develop and commercialize antibody-based  products.  The  collaboration agreement
provides Sanofi with worldwide development and commercialization  rights to new antibody-based
products directed to targets that are included  in the collaboration,  including the  exclusive  right to use
the Company’s maytansinoid ADC technology in the creation  of products developed to these targets.
The product candidates (targets) as of  June 30, 2015  in the collaboration  include isatuximab (CD38),
SAR566658 (CA6), SAR408701 (CEACAM5) and one earlier-stage compound that has yet to be
disclosed.

The Company is entitled to receive milestone payments  potentially totaling $21.5 million,  per

target, plus royalties on the commercial  sales of any  resulting products. The total milestones are
categorized as follows: development milestones—$7.5 million; and regulatory milestones—$14  million.
Through June 30, 2015, the Company  has  received  and recognized an aggregate of  $20.5 million in
milestone payments for compounds covered  under this agreement  now or in  the past, including a
$3 million development milestone related  to initiation  of a Phase IIb clinical trial (as defined in the
agreement) for isatuximab and a $1 million development milestone related to initiation of  a Phase I
clinical trial for SAR408701 which are  included in  license and milestone fee revenue for  the year ended
June 30, 2015, as well as a $500,000 development milestone  related  to  an  undisclosed target which  is
included in license and milestone fee  revenue for the year  ended  June  30, 2013. The next potential
milestone the Company will be entitled  to  receive  for each  of  SAR566658  and SAR408701 will be a
development milestone for initiation  of a  Phase IIb clinical trial  (as defined in  the agreement), which
will result in each  case in a $3 million payment being due. The next potential milestone the  Company
will be entitled to receive with respect to isatuximab will be  a  development milestone for initiation of a
Phase III clinical trial, which will result  in a  $3 million payment being due. The next potential
milestone the Company will be entitled  to  receive  for the  unidentified  target will  be  a development
milestone for commencement of a Phase I  clinical  trial,  which will result in a $1 million  payment being
due. At the time of execution of this  agreement,  there was significant uncertainty  as to whether these
milestones would be achieved. In consideration of this,  as well as  the Company’s  past involvement in
the research and manufacturing of these  product candidates, these milestones were deemed substantive.

In December 2006, the Company entered into a right-to-test agreement with Sanofi. The

agreement provides Sanofi with the right  to (a) test  the Company’s maytansinoid  ADC technology with
Sanofi’s antibodies to targets under a  right-to-test, or research, license, (b)  take exclusive options, with
certain restrictions, to specified targets for specified option periods and (c) upon  exercise  of those
options, take exclusive licenses to use  the  Company’s  maytansinoid  ADC technology  to  develop  and
commercialize products directed to the  specified targets on terms  agreed upon  at the inception of the
right-to-test agreement. The Company received upfront  payments of $4 million  under the  right-to-test
agreement, of which $500,000 was received in  December 2006 upon execution  of  the agreement and
$3.5 million was received in August 2008  upon Sanofi’s activation of its rights under  the agreement.
The right-to-test agreement had a three-year original term  from  the activation date  and was  renewed by

90

IMMUNOGEN, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

AS OF JUNE 30, 2015

C. Agreements (Continued)

Sanofi in August 2011 for its final three-year  term by payment  of a $2 million fee. Sanofi  no longer has
the right to take additional options under the  agreement, although  multiple outstanding  options remain
in effect for the remainder of their respective  option periods. For each  development and
commercialization license taken, the  Company is entitled to receive an exercise fee of $2  million and
up to a total of $30 million in milestone payments,  plus royalties  on the commercial  sales of  any
resulting products. The total milestones  are categorized as follows: development  milestones—
$10 million; and regulatory milestones—$20 million. Sanofi is responsible for  the manufacturing,
product  development and marketing  of any products  resulting from the agreement.

In December 2013, Sanofi took its first exclusive development and commercialization  license under

the right-to-test agreement, for which  the Company received an  exercise fee  of $2 million and was
recognizing this amount as revenue ratably over  the Company’s  estimated  period of its substantial
involvement. The Company had previously estimated this development period would conclude at the
end of non-pivotal Phase II testing. During the current period, the Company determined  it will not be
substantially involved in the development  and commercialization of the product  based on  Sanofi’s
current plans to develop and manufacture the product without the assistance  of the Company.  As a
result of this determination, the Company  recognized the balance of the  upfront exercise fee during the
first quarter of fiscal 2015. This change  in estimate  results in an increase to license and milestone fees
of $1.5 million for the year ended June 30,  2015 compared to amounts that  would have been
recognized pursuant to the Company’s previous estimate. The  next payment the  Company could receive
would either be a $2 million development milestone  payment with the initiation of a  Phase I clinical
trial under the first development and commercialization license taken, or a  $2 million exercise fee for
the execution of a second license. At  the time of execution of this agreement, there  was significant
uncertainty as to whether the milestone related  to  initiation of a Phase I clinical  trial under the  first
development and commercialization license would be achieved. In consideration of this, as well  as the
Company’s expected involvement in the research and manufacturing of these product  candidates, this
milestone was deemed substantive.

Biotest

In July 2006, the Company granted Biotest an  exclusive  development and commercialization
license to our maytansinoid ADC technology for use with antibodies  that  target  CD138. The product
candidate indatuximab ravtansine is in  development under  this  agreement.  Biotest  is responsible for the
manufacturing, product development and marketing of any products resulting from the  agreement. The
Company received a $1 million upfront payment upon execution of  the  agreement and  could  receive up
to $35.5 million in milestone payments, as  well as  royalties on  the commercial sales of any resulting
products. The total milestones are categorized  as follows:  development milestones—$4.5 million;  and
regulatory milestones—$31 million. The Company receives payments for manufacturing any preclinical
and clinical materials made at the request  of Biotest. In September 2008,  Biotest  began Phase I
evaluation of indatuximab ravtansine  which  triggered a $500,000 milestone payment to the Company.
The next potential milestone we will be entitled to receive  will be a development milestone for
commencement of a Phase IIb clinical trial (as defined in the  agreement)  which will result  in a
$2 million payment being due. At the time of execution of this agreement, there  was significant
uncertainty as to whether these milestones  would be achieved.  In consideration  of  this,  as well as  the

91

IMMUNOGEN, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

AS OF JUNE 30, 2015

C. Agreements (Continued)

Company’s past involvement in the research and manufacturing  of  this product, these milestones were
deemed substantive.

The agreement also provided the Company with  the right to elect at specific  stages during the

clinical evaluation of any compound  created under this  agreement, to participate in the U.S.
development and commercialization of that compound in lieu of receiving  the milestone payments not
yet earned and royalties on sales in the U.S. Currently, the Company  can  exercise  this  right during an
exercise period specified in the agreement by  notice  and  payment to Biotest of an agreed  upon opt-in
fee of $15 million. Upon exercise of  this right,  the Company would share equally with Biotest the
associated further costs of product development and commercialization  in the U.S. along with the
profit, if any, from product sales in the  U.S. The Company  would also be  entitled to receive  royalties,
on a reduced basis, on product sales  outside the U.S.

Costs directly attributable to the Biotest  collaborative agreement are  comprised of  compensation
and benefits related to employees who provided research and development services  on behalf of  Biotest
as well as costs of  clinical materials sold. Indirect  costs are  not  identified to individual collaborators.
The costs related to the research and  development  services  amounted to  approximately $309,000,
$305,000 and $339,000 for fiscal years  2015,  2014 and  2013, respectively. The costs  related to clinical
materials sold were approximately $3 million,  $670,000 and  $577,000 for fiscal years 2015,  2014 and
2013, respectively.

Bayer HealthCare

In October 2008, the Company granted Bayer HealthCare an exclusive development and

commercialization license to the Company’s  maytansinoid ADC technology for  use with  antibodies or
other proteins that target mesothelin. Bayer HealthCare is  responsible for the  research,  development,
manufacturing and marketing of any products resulting from the license. The Company received a
$4 million upfront payment upon execution  of the agreement,  and—for  each compound developed and
marketed by Bayer HealthCare under  this collaboration—the Company is  entitled to receive  a total of
$170.5 million in milestone payments, plus  royalties on the commercial sales of any resulting  products.
The total milestones are categorized  as follows: development milestones—$16  million; regulatory
milestones—$44.5 million; and sales milestones—$110 million. Through June 30,  2015, the Company
has received and recognized an aggregate  of $3 million in milestone payments under this agreement.  At
the time of execution of this agreement, there was significant uncertainty as to whether these received
and recognized milestones would be achieved. In  consideration of this, as well as the Company’s past
involvement in the research and supply  of  cytotoxic agent for this product  candidate, these milestones
were deemed substantive. The next potential  milestone the Company will  be  entitled to receive will be
a development milestone for commencement of  a non-pivotal Phase II  clinical trial,  which will result in
a $4 million payment being due. At the time of execution of this  agreement,  there was significant
uncertainty as to whether this milestone would be achieved.  In consideration  of this,  as well as the
Company’s past involvement in the research and supply of cytotoxic agent for this product candidate,
this  milestone was deemed substantive.

The Company had previously deferred the  $4 million upfront payment received  and was

recognizing this amount as revenue ratably over  the estimated period of substantial  involvement. The
Company had previously estimated this  development period would  conclude at the  end of non-pivotal

92

IMMUNOGEN, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

AS OF JUNE 30, 2015

C. Agreements (Continued)

Phase II testing. During the first quarter of fiscal 2012, Bayer HealthCare initiated Phase I clinical
testing of its product candidate. In reaching this stage of clinical testing, Bayer  HealthCare developed
its  own processes for manufacturing required clinical  material  and produced clinical  material  in its own
manufacturing facility. Considering that Bayer HealthCare was  able to accomplish  this without
significant reliance on the Company,  and  considering  that the Company’s expected future involvement
would be primarily supplying Bayer HealthCare with  small quantities  of  cytotoxic  agents for  a limited
period of time, the Company believed its period of  substantial involvement would end  prior to the
completion of non-pivotal Phase II testing. As a result  of this determination,  beginning  in September
2011, the Company recognized the balance of the upfront payment as  revenue ratably through
September 2012. Costs directly attributable to the  Bayer  collaborative agreement related  to  costs of
clinical materials sold were approximately  $297,000  for fiscal year  2013. There were no  similar costs
recorded  in fiscal years 2015 and 2014.

Novartis

Novartis had the right to take six exclusive development and commercialization  licenses under a
right-to-test agreement established in October 2010,  and took these licenses prior to the  expiration of
the agreement in October 2014. The Company received a  $45  million  upfront payment  in connection
with the execution of the right-to-test  agreement in  2010, and  for each development and
commercialization license taken for a specific  target, the Company received an  exercise fee  of
$1 million and is entitled to receive up  to  a total of $199.5  million in milestone payments, plus royalties
on the commercial sales of any resulting  products. The total milestones are categorized as follows:
development milestones—$22.5 million; regulatory milestones—$77  million; and sales  milestones—
$100 million. The initial three-year term of the right-to-test agreement was  extended by Novartis in
October 2013 for an additional one-year period by  payment of a  $5 million fee  to  the Company. The
Company also is entitled to receive payments for  research  and development  activities performed on
behalf of Novartis. Novartis is responsible  for the manufacturing, product development and marketing
of any products resulting from this agreement.

In March 2013, the Company and Novartis amended the right-to-test agreement so that Novartis
could take a license to develop and commercialize  products directed  at  two undisclosed,  related targets,
one target licensed on an exclusive basis  and  the other target initially licensed on a non-exclusive basis.
The target licensed on a non-exclusive  basis  may no  longer be converted  to an  exclusive  target  due  to
the expiration of the right-to-test agreement. The Company  received a $3.5  million fee in  connection
with the execution of the amendment  to  the  agreement. The Company may  be  required to credit this
fee against future milestone payments  if Novartis discontinues  the  development of a specified product
under certain circumstances.

In connection with the amendment, in  March 2013, Novartis took the license referenced above

under the right-to-test agreement, as  amended,  enabling  it to develop and commercialize products
directed at the two targets. The Company  received a $1 million upfront fee  with the execution  of  this
license. Additionally, the execution of  this license provides the  Company the opportunity to receive
milestone payments totaling $199.5 million (development milestones—$22.5  million; regulatory
milestones—$77 million; and sales milestones—$100  million) or $238  million (development

93

IMMUNOGEN, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

AS OF JUNE 30, 2015

C. Agreements (Continued)

milestones—$22.5 million; regulatory  milestones—$115.5  million; and sales milestones—$100 million),
depending on the composition of any resulting products.

In October 2013 and November 2013, Novartis  took its second and third exclusive licenses to
single targets, and in October 2014, took  three  remaining exclusive licenses, each triggering a $1  million
payment to the Company and the opportunity to receive milestone payments totaling $199.5 million, as
outlined above, plus royalties on the  commercial sales  of any resulting products. In January 2015  and
May 2015, Novartis initiated Phase I,  first-in-human clinical testing of its cKit-targeting  ADC product
candidate, LOP628, and P-cadherin-targeting ADC product  candidate, PCA062, respectively,  triggering
a $5 million development milestone payment to the  Company with  each event, both of which are
included in license and milestone fee  revenue for the year  ended  June  30, 2015. The next payment the
Company could receive would be either  a  $7.5 million development milestone for commencement of a
Phase II clinical trial under these two licenses  or a $5  million  development milestone for
commencement of a Phase I clinical  trial under any of its other four licenses.  At the time of execution
of these  agreements, there was significant uncertainty as  to whether these  milestones would  be
achieved. In consideration of this, as  well  as the Company’s  past  involvement in the research and
manufacturing of these product candidates, these  milestones were  deemed substantive. Additionally, the
Company is entitled to receive royalties  on  product sales, if any.

In accordance with ACS 605-25 (as amended  by  ASU  No. 2009-13), the  Company identified all of

the deliverables at the inception of the  right-to-test agreement and subsequently when amended. The
significant deliverables were determined to be the right-to-test, or research,  license, the  development
and commercialization licenses, rights  to  future technological improvements, and  the research services.
The options to obtain development and commercialization licenses in the  right-to-test  agreement were
determined not to  be substantive and, as  a  result, the exclusive development  and commercialization
licenses were considered deliverables  at the inception  of  the right-to-test agreement. Factors that were
considered in determining the options were not substantive  included (i) the overall objective of the
agreement was for Novartis to obtain development  and  commercialization licenses, (ii) the  size of the
exercise fee of $1 million for each development  and commercialization license  obtained  is not
significant relative to the $45 million  upfront payment  that was due at the  inception of the right-to-test
agreement, (iii) the limited economic  benefit that Novartis could  obtain  from the right-to-test
agreement unless it exercised its options  to  obtain  development and commercialization licenses, and
(iv) the  lack of economic penalties as  a  result  of  exercising the  options.

The Company has determined that the research license together with the development and

commercialization licenses represent  one  unit  of  accounting as the  research license  does not have
stand-alone value from the development and commercialization licenses due to the lack of
transferability of the research license and the limited economic benefit Novartis would  derive  if they
did not obtain any development and commercialization licenses. The Company  has also  determined
that this unit of accounting does have stand-alone value from  the  rights to future technological
improvements and the research services. The rights to future technological improvements and the
research services are considered separate units of  accounting as each  of these  was determined to have
stand-alone value. The rights to future technological improvements have  stand-alone value as Novartis
would be able to use those items for  their  intended purpose without  the undelivered elements. The
research services have stand-alone value  as similar services are sold separately by other vendors.

94

IMMUNOGEN, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

AS OF JUNE 30, 2015

C. Agreements (Continued)

The estimated selling prices for the development  and commercialization licenses  are the
Company’s best estimate of selling price  and were determined  based on market conditions,  similar
arrangements entered into by third parties, including  the Company’s understanding of pricing terms
offered by its competitors for single-target development and commercialization licenses that utilize
ADC technology, and entity-specific factors such as the pricing terms  of  the Company’s previous single-
target development and commercialization licenses, recent preclinical  and clinical testing  results of
therapeutic products that use the Company’s ADC technology, and the Company’s pricing practices and
pricing objectives. The estimated selling  price of the right to technological improvements is the
Company’s best estimate of selling price  and was determined by  estimating the probability  that
technological improvements will be made and the probability that  such technological improvements
made will be  used by Novartis. In estimating  these probabilities, we considered  factors such  as the
technology that is the subject of the development and commercialization licenses, our history of  making
technological improvements, and when  such  improvements, if any, were  likely  to  occur relative to the
stage of development of any product candidates pursuant  to  the development and commercialization
licenses. The  Company’s estimate of probability  considered the likely period of time that any
improvements would be utilized, which  was estimated to be ten  years  following delivery of a
commercialization and development license. The value of any  technological improvements made
available after this ten year period was considered  to  be de minimis due to the significant additional
costs that would be incurred to incorporate such technology into any existing  product candidates.  The
estimate of probability was multiplied  by  the estimated selling price of the development and
commercialization licenses and the resulting cash flow was discounted at a  rate of  16%, representing
the Company’s estimate of its cost of capital at the time. The estimated selling price of the  research
services was based on third-party evidence given the  nature of the  research  services to be performed
for Novartis and market rates for similar services.

Upon payment of the extension fee in October 2013, the  total  arrangement consideration  of
$60.2 million (which comprises the $45  million upfront payment, the amendment fee of $3.5  million,
the $5 million extension fee, the exercise fee  for each license, and the  expected fees for the research
services to be provided under the remainder of the  arrangement) was reallocated to the deliverables
based on the relative selling price method  as follows: $55  million to the  delivered and undelivered
development and commercialization licenses; $4.5  million  to  the rights  to  future technological
improvements; and $710,000 to the research services.  The  Company recorded $25.7 million  of the
$55 million of the arrangement consideration outlined above  for the  three development and
commercialization licenses taken in October 2014, which is  included in license and milestone fee
revenue for the year ended June 30, 2015, $17.2 million  for  the two development and
commercialization licenses taken by Novartis in  October 2013  and November 2013, which is included in
license and milestone fee revenue for the year ended  June  30, 2014, and  $11.1 million for the
development and commercialization licenses taken in March  2013, which  is included in license and
milestone fee revenue for the year ended June 30, 2013. The Company  also recorded a cumulative
catch-up of $1 million for the license  delivered in  March 2013 and the  delivered portion  of the license
covering future technological improvements, which  is included  in license and  milestone fee revenue  for
the year ended June 30, 2014.

95

IMMUNOGEN, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

AS OF JUNE 30, 2015

C. Agreements (Continued)

Since execution of the first development and commercialization  license  taken in  March 2013, the

amount of the total arrangement consideration allocated to future technological improvements  is being
recognized as revenue ratably over the period  the Company is  obligated  to  make available any
technological improvements, which is equivalent to the  estimated  term of the agreement.  The  Company
estimates the term of a development and commercialization license to be  approximately  25 years, which
reflects management’s estimate of the  time necessary to develop and commercialize products pursuant
to the license plus  the estimated royalty  term. The Company reassesses  the estimated term at the end
of each reporting period. The Company will  recognize research services revenue as the related services
are delivered.

Costs directly attributable to the Novartis collaborative agreement  are comprised of compensation

and benefits related to employees who provided research and development services  on behalf of
Novartis as well as costs of clinical materials sold. Indirect costs  are not identified to individual
collaborators. The costs related to the research and development  services  amounted  to  $141,000,
$1.4 million and $2.4 million for fiscal  years 2015, 2014  and 2013,  respectively.  The  costs related to
clinical materials sold were approximately  $644,000,  $1.3 million and $134,000 for fiscal years 2015,
2014 and 2013, respectively.

Lilly

Eli Lilly and Company (Lilly) had the right to take three exclusive development  and

commercialization licenses under a right-to-test  agreement established  in December  2011, and  took
these licenses prior to the expiration of  the agreement  in December  2014. The Company received a
$20 million upfront payment in connection  with the  execution  of  the right-to-test agreement in 2011.
Under the terms of this right-to-test agreement,  the first license had  no associated  exercise  fee,  and the
second  and third licenses each had a  $2 million  exercise fee. The first development and
commercialization license was taken  in  August 2013  and the  agreement was amended in December
2013 to provide Lilly with an extension provision  and retrospectively  include  a $2 million exercise fee
for the first license in lieu of the fee due for  either the  second or third license.  The  second and  third
licenses were taken in December 2014,  with one including the $2 million  exercise fee  and the  other not.
Under the two licenses with the $2 million  exercise  fee, the Company  is entitled to receive  up to a total
of $199 million in milestone payments,  plus royalties on the commercial  sales of  any resulting products.
Under the license taken in December  2014 without the exercise fee, the Company is entitled to receive
up to a total of $200.5 million in milestone payments,  plus royalties  on the commercial  sales of  any
resulting products. The total milestones  are categorized as follows: development  milestones—
$29 million for the two development and commercialization licenses with  the $2 million exercise fee,
and $30.5 million for the one development and commercialization  license with  no exercise fee;
regulatory milestones—$70 million in  all  cases; and  sales  milestones—$100 million in all cases.  The
next payment the Company could receive  would be a $5 million  development milestone payment with
the initiation of a Phase I clinical trial under any of these three  development  and commercialization
licenses taken. At the time of execution of this  agreement, there was significant uncertainty  as to
whether these milestones related to initiation of a Phase  I clinical trial under the development and
commercialization licenses would be  achieved. In consideration of this, as  well as the  Company’s
expected involvement in the research  and manufacturing of these product candidates,  these milestones
were deemed substantive. The Company also is entitled  to  receive payments for  delivery of cytotoxic

96

IMMUNOGEN, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

AS OF JUNE 30, 2015

C. Agreements (Continued)

agents to Lilly and research and development activities performed on behalf  of Lilly. Lilly is responsible
for the manufacturing, product development  and marketing of any  products resulting  from this
collaboration.

In accordance with ASC 605-25 (as amended by ASU No.  2009-13), the Company identified all of

the deliverables at the inception of the  right-to-test agreement. The  significant deliverables  were
determined to be the right-to-test, or research,  license, the  exclusive  development and
commercialization licenses, rights to  future technological  improvements, delivery of  cytotoxic  agents and
the research services. The options to  obtain development  and  commercialization  licenses  in the
right-to-test agreement were determined not to be substantive and, as a result, the exclusive
development and commercialization licenses were considered deliverables at  the inception of the
right-to-test agreement. Factors that  were  considered in  determining the options were not substantive
included (i) the overall objective of the agreement was for Lilly to obtain development and
commercialization licenses, (ii) the size  of  the exercise fees of  $2 million  for each development and
commercialization license taken beyond the first license is not significant relative to the $20 million
upfront payment that was due at the  inception of the  right-to-test agreement, (iii) the  limited economic
benefit that Lilly could obtain from the right-to-test agreement  unless it exercised its options to obtain
development and commercialization licenses, and  (iv) the lack  of economic penalties  as a result  of
exercising the options.

The Company has determined that the research license together with the development and

commercialization licenses represent  one  unit  of  accounting as the  research license  does not have
stand-alone value from the development and commercialization licenses due to the lack of
transferability of the research license and the limited economic benefit Lilly  would derive if they  did
not obtain any development and commercialization licenses. The Company has also determined  that
this  unit of accounting has stand-alone value from  the rights  to  future technological improvements, the
delivery of cytotoxic agents and the research  services. The rights to future technological improvements,
delivery of cytotoxic agents and the research  services are considered separate  units of accounting as
each  of these was  determined to have  stand-alone value. The rights  to  future  technological
improvements have stand-alone value as Lilly would be able to use  those  items for  their  intended
purpose without the undelivered elements. The research  services  and cytotoxic agents  have stand-alone
value as similar services and products  are  sold separately by other vendors.

The estimated selling prices for the development  and commercialization licenses  are the
Company’s best estimate of selling price  and were determined  based on market conditions,  similar
arrangements entered into by third parties, including  pricing  terms offered by our competitors for
single-target development and commercialization  licenses that  utilize antibody-drug conjugate
technology, and entity-specific factors  such as  the pricing  terms of the  Company’s previous  single-target
development and commercialization licenses, recent preclinical and clinical testing  results of therapeutic
products that use the Company’s ADC  technology,  and the  Company’s pricing practices and pricing
objectives. The estimated selling price of the rights to technological improvements is the  Company’s
best estimate of selling price and was determined by estimating the probability that technological
improvements will be made, and the probability  that technological  improvements  made will be used by
Lilly. In estimating these probabilities, we considered factors  such as the  technology that is  the subject
of the development and commercialization  licenses, our history of  making technological improvements,

97

IMMUNOGEN, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

AS OF JUNE 30, 2015

C. Agreements (Continued)

and when such improvements, if any,  were likely  to  occur relative to the stage  of development of any
product  candidates pursuant to the development and commercialization  licenses.  The  company’s
estimate of probability considered the  likely  period of time that  any improvements would be utilized,
which  was estimated to be ten years following delivery of a  commercialization and development license.
The value of any technological improvements  made available after this ten year  period was  considered
to be de minimis due to the significant additional costs  that would be incurred to incorporate such
technology into any existing product candidates.  The estimate  of  probability was multiplied by the
estimated selling price of the development  and commercialization licenses  and the  resulting cash flow
was discounted at a rate of 16%, representing the Company’s  estimate of its cost  of capital at  the time.
The estimated selling price of the cytotoxic agent  was based on third-party  evidence given market rates
for the manufacture of such cytotoxic agents. The estimated selling price of  the research services was
based on third-party evidence given the nature of the research services  to  be  performed for Lilly  and
market rates for similar services.

The total arrangement consideration  of $28.2 million (which comprises the $20 million upfront
payment, the exercise fee, if any, for  each license, the expected fees for the research services to be
provided and the cytotoxic agent to be  delivered  under the arrangement)  was  allocated  to  the
deliverables based on the relative selling price method as follows: $23.5  million  to  the development and
commercialization licenses; $0.6 million  to  the rights to future technological improvements, $0.8 million
to the sale of cytotoxic agent; and $3.3  million  to  the research services. Upon execution of the
development and commercialization license taken by  Lilly in  August 2013, the Company recorded
$7.8 million of the $23.5 million of the arrangement  consideration outlined above, which  is included in
license and milestone fee revenue for the year ended  June  30, 2014. With this first development and
commercialization license taken, the  amount of the total arrangement consideration allocated to future
technological improvements will commence  to  be  recognized as  revenue  ratably over  the period  the
Company is obligated to make available any technological  improvements, which  is the equivalent to the
estimated term of the license. The Company estimates  the term of  a  development and
commercialization license to be approximately 25 years, which  reflects  management’s estimate of the
time necessary to develop and commercialize  therapeutic  products  pursuant to the  license plus the
estimated royalty term. The Company  will reassess the estimated term at each  subsequent reporting
period. Upon execution of two development and commercialization licenses taken  by  Lilly in  December
2014, the Company recognized as license revenue the  remaining  $15.6 million of arrangement
consideration allocated to the development and commercialization  licenses, which is included in  license
and milestone fee revenue for the year  ended June 30, 2015.  The  Company will recognize research
services revenue and revenue from the delivery of cytotoxic agents  as the related  services and  cytotoxic
agents are delivered.

Costs directly attributable to the Lilly collaborative agreement are comprised of compensation and

benefits related to employees who provided research  and development  services  on behalf  of  Lilly as
well as costs of clinical materials sold. Indirect costs are not identified  to  individual collaborators. The
costs related to the research and development services amounted  to  approximately $499,000,
$1.2 million and $310,000 for fiscal years  2015, 2014 and 2013 respectively.  The costs related to clinical
materials sold were approximately $1.1 million,  $26,000 and  $10,000 for fiscal years 2015,  2014 and
2013, respectively.

98

IMMUNOGEN, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

AS OF JUNE 30, 2015

C. Agreements (Continued)

CytomX

In January 2014, the Company entered into a  reciprocal right-to-test agreement with CytomX

Therapeutics, Inc. (CytomX). The agreement provides CytomX with  the right to test the Company’s
ADC technology with CytomX Probodies(cid:5) to create Probody-drug conjugates (PDCs)  directed to a
specified number of targets under a right-to-test, or research, license, and to subsequently  take an
exclusive, worldwide license to use the Company’s ADC technology to develop  and commercialize
PDCs directed to the specified targets  on terms agreed  upon at the inception of the right-to-test
agreement. The Company received no  upfront cash payment  in connection  with the execution of  the
right-to-test agreement. Instead, the Company  received  reciprocal rights to CytomX’s  Probody
technology whereby the Company was provided the right to test CytomX’s Probody technology  to
create PDCs directed to a specified number of  targets and to subsequently take exclusive, worldwide
licenses to develop and commercialize  PDCs  directed to the specified  targets on  terms agreed  upon at
the inception of the right-to-test agreement. The terms of the right-to-test agreement require  the
Company and CytomX to each take its  respective development and commercialization licenses by the
end of the term of the research licenses. In addition, both the Company  and  CytomX are  required to
perform specific research activities under  the right-to-test  agreement on  behalf of the other party  for
no monetary consideration.

With respect to the development and  commercialization license that may be taken by CytomX, the
Company is entitled to receive up to  a total  of  $160 million in milestone  payments plus royalties on the
commercial sales of any resulting product.  The total milestones are categorized as  follows: development
milestones—$10 million; regulatory milestones—$50  million; and sales milestones—$100 million.
Assuming no annual maintenance fee is  payable as  described below, the next  payment the  Company
could receive would be a $1 million development milestone  payment with  commencement of  a Phase I
clinical trial. At the time of execution of  the right-to-test agreement,  there was significant  uncertainty as
to whether the milestone related to the  Phase I clinical trial would be achieved. In consideration of
this, as well as the Company’s expected  involvement  in the research and manufacturing of any  product
candidate, this milestone was deemed  substantive.  CytomX is  responsible  for the  manufacturing,
product  development and marketing  of any PDC resulting  from  the development  and
commercialization license taken by CytomX under this collaboration.

With respect to any development and  commercialization license that may be taken  by  the
Company, the Company will potentially be required to pay up to a total of $80  million in milestone
payments per license, plus royalties on  the commercial sales  of any  resulting product. The total
milestones per license are categorized as  follows: development milestones—$7 million; regulatory
milestones—$23 million; and sales milestones—$50  million. Assuming no  annual maintenance  fee  is
payable as described below, the next payment the Company  could be required  to  make is a $1  million
development milestone payment with commencement of a  Phase I clinical trial. The Company  is
responsible for the manufacturing, product development and marketing of any PDC resulting  from any
development and commercialization license taken by  the Company under this collaboration.

In addition, each party may be liable to pay annual maintenance fees to the other  party if  the

licensed PDC product candidate covered  under each development and commercialization  license has
not progressed to a specified stage of development within  a specified time frame.

99

IMMUNOGEN, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

AS OF JUNE 30, 2015

C. Agreements (Continued)

The arrangement was accounted for  based on  the fair  value  of  the items  exchanged. The items to

be delivered to CytomX under the arrangement are accounted for under the Company’s  revenue
recognition policy. The items to be received from CytomX are recorded  as research and development
expenses as incurred.

In accordance with ASC 605-25 (as amended by ASU No.  2009-13), the Company identified all of

the deliverables at the inception of the  right-to-test agreement. The  significant deliverables  were
determined to be the right-to-test, or research,  license, the  exclusive  development and
commercialization license, rights to future technological improvements, and the research services. The
research license in the right-to-test agreement was  determined not to be substantive and,  as a result,
the exclusive development and commercialization license was considered a deliverable at the inception
of the right-to-test agreement. Factors  that were  considered in determining the research license was not
substantive included (i) the overall objective of  the agreement is for CytomX to obtain a development
and commercialization license, (ii) there  are no exercise fees payable  upon taking  the development and
commercialization license, (iii) the limited economic benefit  that CytomX could obtain from  the
right-to-test agreement unless CytomX was able to take  the development and commercialization
license, and (iv) the lack of economic penalties as a result of taking  the license.

The Company has determined that the research license from the  Company to CytomX together
with the development and commercialization license  from the Company to CytomX represent  one  unit
of accounting as the research license  does not have stand-alone value from  the development and
commercialization license due to the  lack of  transferability of  the research license and  the limited
economic benefit CytomX would derive if  they did  not  obtain  any development and  commercialization
license. The Company has also determined that this unit  of accounting has stand-alone value  from the
rights to future technological improvements  and  the research services. The rights  to  future
technological improvements and the  research  services are considered separate  units of accounting as
each  of these was  determined to have  stand-alone value. The rights  to  future  technological
improvements have stand-alone value as CytomX would be able to use  those items for their  intended
purpose without the undelivered elements. The research  services  have stand-alone  value as  similar
services are sold separately by other  vendors.

The estimated selling price for the development and commercialization  license is the Company’s

best estimate of selling price and was determined based  on market conditions, similar arrangements
entered into by third parties, including  pricing terms offered by the Company’s competitors for single-
target development and commercialization licenses that utilize antibody-drug conjugate technology,  and
entity-specific factors such as the pricing  terms of the Company’s previous single-target development
and commercialization licenses, recent preclinical and clinical testing results of therapeutic products
that use the Company’s ADC technology, and the Company’s pricing practices  and pricing objectives.
In order to determine the best estimate  of selling  price, the Company determined the overall value of a
license by calculating a risk-adjusted  net present value of a  recent,  comparable transaction  the
Company entered into with another collaborator. This overall value was then decreased by
risk-adjusting the net present value of the contingent  consideration (the milestones  and royalties)
payable by CytomX under the development and commercialization license.  This amount represents  the
value that a third party would be willing to pay  as an upfront  payment for this license  to  the
Company’s technology.

100

IMMUNOGEN, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

AS OF JUNE 30, 2015

C. Agreements (Continued)

The estimated selling price of the rights to technological improvements  is the  Company’s best

estimate of selling price and was determined by  estimating  the probability  that  technological
improvements will be made, and the probability  that technological  improvements  made will be used by
CytomX. In estimating these probabilities,  the Company considered factors  such as  the technology that
is the subject of the development and commercialization license, the Company’s history  of making
technological improvements, and when  such  improvements, if any, were  likely  to  occur relative to the
stage of development of the product candidate pursuant to the development  and commercialization
license. The Company’s estimate of probability  considered the likely period of time that any
improvements would be utilized, which  was estimated to be ten  years  following delivery of the
commercialization and development license. The value of any  technological improvements made
available after this ten year period was considered  to  be de minimis due to the significant additional
costs that would be incurred to incorporate such technology into any existing  product candidate.  The
estimate of probability was multiplied  by  the estimated selling price of the development and
commercialization license and the resulting cash flow was discounted at a  rate of  13%, representing the
Company’s estimate of its cost of capital at  the time.

The estimated selling price of the research  services  was based on third-party evidence  given the

nature of the research services to be performed for  CytomX and market rates for  similar services.

The total allocable consideration of $13.1 million (which comprises the  $13.0 million that a third
party would be willing to pay as an upfront payment for this license  to  the  Company’s technology plus
$140,000 for the fair value of fees for  the research services to be provided)  was  allocated  to  the
deliverables based on the relative selling price method as follows: $12.7  million  to  the development and
commercialization license; $350,000 to the rights  to  future technological improvements and $140,000 to
the research services. The Company will  recognize as license revenue the amount of the  total  allocable
consideration allocated to the development and commercialization  license when the development  and
commercialization license is delivered  to  CytomX.  At  the time the license is taken,  the amount of the
total allocable consideration allocated  to  future  technological improvements  will  commence to be
recognized as revenue ratably over the period  the Company is  obligated  to  make available any
technological improvements, which is the equivalent  to  the estimated term of the  license. The  Company
estimates the term of a development and commercialization license to be  approximately  25 years, which
reflects management’s estimate of the  time necessary to develop and commercialize therapeutic
products pursuant to the license plus the  estimated royalty term. The Company will be required to
reassess the estimated term at each subsequent reporting period.  The Company  does not control when
CytomX will take the development and  commercialization  license.  As a result, the Company  cannot
predict when it will recognize the related  license revenue except that  it will  be  within the term  of the
research license. The Company will recognize research services revenue as  the related services  are
delivered.

No license fee revenue has been recognized  related to this agreement through  June 30, 2015 as  the

research license was not considered to be substantive  and the  development and  commercialization
license had not been delivered at this  time.  Accordingly,  $13.0 million of  allocated arrangement
consideration is included in long-term  deferred revenue at June 30, 2015.

The $13.1 million of total allocable consideration  to  be  accounted for  as revenue described  above

is also the amount that was used to account  for the  expense of the  licenses and research services the

101

IMMUNOGEN, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

AS OF JUNE 30, 2015

C. Agreements (Continued)

Company received or will receive from CytomX. Based  on an  estimate of the  research  services  that
CytomX will be providing to the Company  for no monetary consideration, $310,000 was allocated to
such services and will be expensed over  the  period the  services  are provided. The balance of
$12.8 million pertains to technology rights received and these amounts have been charged to research
and development expense during the year  ended June  30, 2014 upon execution of the  research
agreement.

Costs directly attributable to the CytomX collaborative  agreement are comprised of compensation

and benefits related to employees who provided research and development services  on behalf of
CytomX. Indirect costs are not identified to individual collaborators. The costs related  to  the research
and development services amounted to approximately $130,000, for  fiscal year 2015. There  were no
similar costs recorded in fiscal years  2014 and 2013.

Takeda

In March 2015, the Company entered into a  right-to-test agreement with  Takeda Pharmaceutical

Company Limited (Takeda) through its  wholly owned  subsidiary, Millennium Pharmaceuticals, Inc.  The
agreement provides Takeda with the  right  to  (a) take exclusive options, with  certain  restrictions, to
individual targets selected by Takeda  for specified option  periods, (b) test the Company’s ADC
technology with Takeda’s antibodies directed to the targets optioned  under a  right-to-test,  or research,
license, and (c) take exclusive licenses to use the  Company’s ADC technology to develop and
commercialize products to targets optioned  for up to two individual targets  on terms  specified in the
right-to-test agreement. Takeda must exercise its  options  for  the  development and  commercialization
licenses by the end of the three-year  term of the right-to-test agreement, after  which any then
outstanding options will lapse. Takeda  has the right to extend the  three-year right-to-test period for  one
additional year by payment to the Company of  $4 million. Alternatively, Takeda has  the right to expand
the scope of the right-to-test agreement  by payment to the Company  of $8 million. If  Takeda opts  to
expand the scope of the right-to-test agreement,  it will be entitled to take  additional exclusive options,
one of which may be exercised for an  additional development  and  commercialization  license, and the
right-to test period will be extended  until the  fifth anniversary  of  the effective date of the right-to-test
agreement. Takeda is responsible for  the  manufacturing,  product development and marketing of any
products resulting from this collaboration.

The Company received a $20 million  upfront payment  in connection with the execution of  the

right-to-test agreement and, for each  development and  commercialization license taken,  is entitled  to
receive up to a total of $210 million  in milestone payments,  plus royalties on the  commercial sales of
any resulting products. The total milestones are categorized as follows: development milestones—
$30 million; regulatory milestones—$85  million; and sales milestones—$95 million.  The first potential
milestone the Company will be entitled  to  receive  will  be  a $5 million development milestone payment
with the initiation of a Phase I clinical trial under the first development and commercialization  license
taken. At the time of execution of this  agreement,  there was significant uncertainty  as to whether the
milestone related to initiation of a Phase I clinical trial under the first  development  and
commercialization license would be achieved. In  consideration of this, as  well  as the Company’s
expected involvement in the research  and manufacturing of these product candidates,  this milestone

102

IMMUNOGEN, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

AS OF JUNE 30, 2015

C. Agreements (Continued)

was deemed substantive. The Company also is  entitled to receive payments for delivery of cytotoxic
agents to Takeda and research and development activities  performed  on behalf of Takeda.

In accordance with ASC 605-25 (as amended by ASU No.  2009-13), the Company identified all of

the deliverables at the inception of the  right-to-test agreement. The  significant deliverables  were
determined to be the right-to-test, or research,  license, the  two  exclusive development and
commercialization licenses, rights to  future technological  improvements, the development and
commercialization license contained in  the option  to  expand  the  agreement and  the research services.
The options to obtain two development and  commercialization licenses in the  right-to-test agreement
were determined not to be substantive and, as a result, the exclusive development and
commercialization licenses were considered deliverables at  the inception of the  right-to-test agreement.
Factors that were considered in determining the  options were not substantive included (i)  the overall
objective of the agreement was for Takeda to obtain development  and  commercialization licenses,
(ii) no additional consideration required for  each development and commercialization license taken
beyond the $20 million upfront payment  that was due at the inception  of  the right-to-test agreement,
(iii) the limited economic benefit that Takeda  could  obtain  from  the right-to-test agreement unless it
exercised its options to obtain development and commercialization  licenses, and (iv) the  lack  of
economic penalties as a result of exercising the  options.

The option to expand the scope of the right-to-test agreement  and  obtain, among other

deliverables, a third development and  commercialization  license  was  not  determined to be substantive
and, as a result, the third development  and commercialization license was considered a deliverable at
the inception of the right-to-test agreement. Factors that were considered  in determining this option
was not substantive included (i) the overall objective of the agreement was  for Takeda  to  obtain
development and commercialization licenses and  (ii)  the relative size of  the  $8 million option  payment
in exchange for this third development and commercialization license and  two year extension of  the
right-to-test period when compared to the  $20 million upfront payment in exchange for,  among  other
deliverables, two development and commercialization licenses and  the separate ability to extend the
right-to-test period for one year in exchange  for  a $4 million payment.

The Company has determined that the research license together with the development and

commercialization licenses represent  one  unit  of  accounting as the  research license  does not have
stand-alone value from the development and commercialization licenses due to the lack of
transferability of the research license and the limited economic benefit Takeda  would derive if they  did
not obtain any development and commercialization licenses. The Company has also determined  that
this  unit of accounting has stand-alone value from  the rights  to  future technological improvements, the
license contained in the option to expand the agreement and the research services. The license
contained in the option to expand the  agreement has stand-alone value as it would result in an
additional license with which Takeda  would derive economic benefit. The rights to future  technological
improvements have stand-alone value as Takeda would be able to use  those items for their intended
purpose without the undelivered elements. The research  services  have stand-alone  value as  similar
services are sold separately by other  vendors.

The estimated selling prices for the development  and commercialization licenses  are the
Company’s best estimate of selling price  and were determined  based on market conditions,  similar
arrangements entered into by third parties, including  pricing  terms offered by our competitors for

103

IMMUNOGEN, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

AS OF JUNE 30, 2015

C. Agreements (Continued)

single-target development and commercialization  licenses that  utilize antibody-drug conjugate
technology, and entity-specific factors  such as  the pricing  terms of the  Company’s previous  single-target
development and commercialization licenses, recent preclinical and clinical testing  results of therapeutic
products that use the Company’s ADC  technology,  and the  Company’s pricing practices and pricing
objectives. The estimated selling price of the rights to technological improvements is the  Company’s
best estimate of selling price and was determined by estimating the probability that technological
improvements will be made, and the probability  that technological  improvements  made will be used by
Takeda. In estimating these probabilities,  the Company considered factors  such as  the technology that is
the subject of the development and commercialization licenses, our history of making technological
improvements, and when such improvements, if any,  were likely  to  occur relative  to  the stage of
development of any product candidates pursuant to the development  and commercialization licenses.
The Company’s estimate of probability considered the  likely period of time that any  improvements
would be utilized, which was estimated  to  be  ten years following delivery of a  commercialization and
development license. The value of any technological improvements made available after this ten year
period was considered to be  de minimis due to the significant additional costs that would  be  incurred to
incorporate such technology into any existing product  candidates. The estimate  of probability was
multiplied by the estimated selling price of the development  and commercialization licenses  and the
resulting cash flow was discounted at a rate of  13%, representing the Company’s estimate of  its cost of
capital at the time. The estimated selling  price of the research  services  was based on third-party
evidence given the nature of the research services to be performed for  Takeda and market rates for
similar services.

The total arrangement consideration  of $31.4 million (which comprises the $20 million upfront

payment, the $8 million payment to expand the agreement and the expected  fees  for the  research
services to be provided) was allocated  to  the deliverables based on the relative selling  price method as
follows: $25.9 million to the three development and commercialization  licenses; $2.1 million to the
rights to future technological improvements; and $3.4 million to the research services.  The  Company
will recognize as license revenue an equal  amount of  the total arrangement consideration  allocated  to
the development and commercialization licenses as  each individual license  is delivered to Takeda upon
Takeda’s exercise of its options to such licenses.  At the  time  the  first development and
commercialization license is taken, the  amount  of  the total arrangement consideration allocated to
future technological improvements will commence to be recognized as revenue ratably over the period
the Company is obligated to make available  any  technological improvements, which is the  equivalent to
the estimated term of the license. The Company estimates the term  of a development and
commercialization license to be approximately 25 years, which  reflects  management’s estimate of the
time necessary to develop and commercialize  therapeutic  products  pursuant to the  license plus the
estimated royalty term. The Company  will reassess the estimated term at each  subsequent reporting
period. The Company does not control when  Takeda will exercise its options  for development  and
commercialization licenses. As a result,  the  Company cannot predict when it will recognize the related
license revenue except that it will be within the term  of  the research license. The Company  will
recognize research services revenue as the  related services are delivered.

Costs directly attributable to the Takeda  collaborative agreement are comprised of compensation

and benefits related to employees who provided research and development services  on behalf of

104

IMMUNOGEN, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

AS OF JUNE 30, 2015

C. Agreements (Continued)

Takeda. Indirect costs are not identified  to  individual collaborators. The costs related  to  the research
and development services amounted to approximately $113,000 for  fiscal year 2015.

Other Collaborative Agreements

In December 2004, the Company entered into a development and license agreement with  a

predecessor to Janssen Biotech (formerly  known as Centocor), a wholly owned subsidiary of Johnson  &
Johnson. Under the terms of this agreement, Janssen  was  granted exclusive worldwide rights  to  develop
and commercialize anticancer therapeutics  that consist of the  Company’s maytansinoid  cell-killing  agent
attached to an (cid:2)v integrin-targeting antibody that was developed  by Janssen. Per notice  to  the
Company, effective July 2014, Janssen  relinquished  its  rights to the target.  Accordingly, the Company
recognized the remaining $241,000 of the  $1 million upfront fee received from Janssen  upon execution
of the 2004 license agreement and is  included in  license and milestone  fee revenue for the fiscal year
ended June 30, 2015.

D. Property and Equipment

Property and equipment consisted of  the following at June 30, 2015 and 2014 (in thousands):

June 30,

2015

2014

Leasehold improvements . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Machinery and equipment . . . . . . . . . . . . . . . . . . . . . . . . . . .
Computer hardware and software . . . . . . . . . . . . . . . . . . . . . .
Furniture and fixtures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Assets under construction . . . . . . . . . . . . . . . . . . . . . . . . . . . .

$ 32,355
18,398
6,897
3,290
2,361

$ 28,464
16,724
5,846
1,876
3,688

Less accumulated depreciation . . . . . . . . . . . . . . . . . . . . . . . .

$ 63,301
(47,047)

$ 56,598
(42,249)

Property and equipment, net

. . . . . . . . . . . . . . . . . . . . . . . . .

$ 16,254

$ 14,349

Depreciation expense was approximately $5.5 million for the year ended June 30,  2015 and

$4.6 million for each of the years ended June  30, 2014 and 2013. Included in the table  above, the
Company’s investment in equipment  under  capital leases was $724,000,  net of accumulated amortization
of $190,000, at June 30, 2015 and $574,000,  net of accumulated amortization of $50,000, at June 30,
2014.

E. Liability Related to Sale of Future Royalties

In April 2015, IRH purchased the right to receive 100% of the royalty payments on commercial

sales of Kadcyla arising under the Company’s  development and commercialization license  with
Genentech, until IRH has received aggregate  royalties equal to $235 million or  $260 million, depending
on when the aggregate royalties received by IRH reach a specified milestone. Once the  applicable
threshold is met, if ever, the Company  will  thereafter receive  85% and IRH will receive 15%  of  the
Kadcyla royalties for the remaining royalty term.  At consummation  of the transaction in  April 2015,  the

105

IMMUNOGEN, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

AS OF JUNE 30, 2015

E. Liability Related to Sale of Future Royalties (Continued)

Company received cash proceeds of $200  million. As part of  this sale, the Company incurred
$5.9 million of transaction costs, which  are presented in  the accompanying consolidated balance sheet
as deferred financing costs and will be amortized  to  interest  expense over  the estimated life of the
royalty purchase agreement. Although the  Company  sold  its rights  to  receive royalties from the sales of
Kadcyla, as a result of its ongoing involvement in the  cash flows related to these royalties, the
Company will continue to account for  these royalties as  revenue and recorded the  $200 million in
proceeds from this transaction as a liability related to sale of future royalties  (Royalty Obligation) that
will be amortized using the interest method over the  estimated  life  of the royalty  purchase  agreement.

The following table shows the activity  within the liability account during  the period  from the

inception of the royalty transaction in April 2015  to  June  30, 2015 (in thousands):

Liability related to sale of future royalties—beginning balance . . . . . . . .
Proceeds from sale of future royalties . . . . . . . . . . . . . . . . . . . . . . . .
Non-cash Kadcyla royalty revenue . . . . . . . . . . . . . . . . . . . . . . . . . . .
Non-cash interest expense recognized . . . . . . . . . . . . . . . . . . . . . . . . .

Period from
inception to
June 30,
2015

$

—
200,000
(5,484)
5,146

Liability related to sale of future royalties—ending  balance . . . . . . . . . . .

$199,662

As royalties are remitted to IRH, the balance  of  the Royalty Obligation will be effectively  repaid
over the life of the agreement. In order to determine the amortization  of the Royalty Obligation,  the
Company is required to estimate the total amount of  future royalty payments to be received and
remitted to IRH as noted above over the life  of the agreement.  The  sum of these amounts less the
$200 million proceeds the Company  received will be recorded as  interest  expense over the  life of the
Royalty Obligation. Since inception, the Company’s estimate of  this total  interest  expense resulted  in an
effective annual interest rate of approximately 10.3%.  The Company periodically  assesses the  estimated
royalty payments to IRH and to the extent such payments  are  greater or less than its initial estimates,
or the timing of such payments is materially different than  its  original estimates, the Company will
prospectively adjust the amortization of  the Royalty Obligation. There are a number of factors that
could materially affect the amount and timing of royalty payments from Genentech, most  of  which are
not within the Company’s control. Such  factors include, but are not limited to, changing  standards of
care, the introduction of competing products, manufacturing or other  delays,  biosimilar competition,
patent protection, adverse events that result in governmental  health  authority  imposed restrictions on
the use of the drug products, significant  changes in foreign  exchange  rates  as the royalties  remitted to
IRH are made in U.S. dollars (USD) while  significant portions of the underlying sales of Kadcyla  are
made in currencies other than USD, and other events or  circumstances that could result in  reduced
royalty payments from Kadcyla, all of which would  result in a reduction of  non-cash royalty  revenues
and the non-cash interest expense over the  life of the Royalty  Obligation.  Conversely, if sales of
Kadcyla are more than expected, the non-cash royalty  revenues  and the non-cash interest expense
recorded  by the Company would be greater over the  term of the Royalty  Obligation.

106

IMMUNOGEN, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

AS OF JUNE 30, 2015

E. Liability Related to Sale of Future Royalties (Continued)

In addition, the royalty purchase agreement grants  IRH the right to receive certain reports and
other information relating to the royalties and contains  other representations and  warranties, covenants
and indemnification obligations that are customary for a transaction of this nature.

F.

Income Taxes

The difference between the Company’s expected tax benefit, as computed by applying the U.S.

federal corporate tax rate of 34% to loss  before the benefit  for income taxes, and actual tax is
reconciled in the following chart (in thousands):

Year Ended June 30,

2015

2014

2013

Loss before income tax expense . . . . . . . . . . . . . . .

$(60,739) $(71,364) $(72,811)

Expected tax benefit at 34% . . . . . . . . . . . . . . . . . .
Permanent differences . . . . . . . . . . . . . . . . . . . . . .
State tax benefit net of federal benefit
. . . . . . . . . .
Increase in valuation allowance, net . . . . . . . . . . . .
Federal research credit . . . . . . . . . . . . . . . . . . . . . .
Federal orphan drug credit . . . . . . . . . . . . . . . . . . .
Expired loss and credit carryforwards . . . . . . . . . . .

$(20,651) $(24,264) $(24,756)
1,540
1,953
(3,921)
(4,062)
25,624
26,011
(2,260)
(1,002)
—
—
3,773
1,364

2,766
(3,252)
27,940
(1,407)
(5,471)
75

Benefit for income taxes . . . . . . . . . . . . . . . . . . . .

$

— $

— $

—

At June  30, 2015, the Company has net operating loss carryforwards of approximately

$249.3 million available to reduce federal  taxable income, if any, that expire in 2020  through 2035 and
$87.1 million available to reduce state taxable income, if any,  that expire  in fiscal 2020 through  fiscal
2035. Included in the federal and state  carryforwards is $25.6 million  and $22.2 million,  respectively,
related to deductions from the exercise  of  stock options and  the  related  tax benefit  which will result in
an increase in additional paid-in capital  if and when realized through a reduction of  taxes paid in  cash.
The Company also has federal and state credit carryforwards of approximately $28 million available to
offset federal and state income taxes, which  expire beginning in  fiscal 2016. Due to the degree of
uncertainty related to the ultimate use of  the loss carryforwards  and tax credits, the Company  has
established a  valuation allowance to fully reserve  these tax benefits.

Deferred income taxes reflect the net  tax effects of  temporary  differences between the  carrying
amounts of assets and liabilities for financial reporting  purposes and the amounts used for income tax

107

IMMUNOGEN, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

AS OF JUNE 30, 2015

F.

Income Taxes (Continued)

purposes. Significant components of the Company’s deferred tax assets and liabilities as  of June  30,
2015 and 2014 are as follows (in thousands):

June 30,

2015

2014

Deferred tax assets:

Net operating loss carryforwards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Federal and state tax credit carryforwards . . . . . . . . . . . . . . . . . . . . . . . . . .
Property and other intangible assets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Deferred revenue . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Stock-based compensation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Deferred lease incentive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Other liabilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Royalty sale . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

$ 89,362
25,131
2,532
16,179
11,379
4,279
3,177
78,427

$ 144,230
14,453
2,386
24,095
9,047
3,908
1,234
—

Total deferred tax assets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

$ 230,466

$ 199,353

Deferred tax liabilities:

Accounting method change . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Royalty sale transaction costs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

(983)
(2,190)

Total deferred tax liabilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

$ (3,173) $

—
—

—

Valuation allowance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

(227,293)

(199,353)

Net deferred tax assets/(liabilities) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

$

— $

—

The valuation allowance increased by $27.9  million  during  2015 due primarily to the tax treatment
of the royalty sale and additional net loss  incurred during the  year, partially  offset by the utilization of
net operating loss carryforwards.

Utilization of the NOL and credit carryforwards  may be subject to a substantial annual limitation
due to ownership change limitations  that have occurred previously or that could occur in the future  as
provided by Section 382 of the Internal Revenue Code of 1986, as well as  similar state  and foreign
provisions. These ownership changes may limit the amount of  NOL  and credit carry forwards that can
be utilized annually to offset future taxable income and tax, respectively. In general, an ownership
change, as defined by Section 382, results from  transactions increasing the ownership  of  certain
shareholders or public groups in the  stock of a corporation  by more than  50 percentage  points over a
three-year period. Since the Company’s  formation, it has  raised  capital  through the issuance of  capital
stock on several occasions (both pre  and post initial  public offering) which,  combined with  the
purchasing shareholders’ subsequent  disposition of those shares, may  have resulted  in a change of
control, as defined by Section 382, or could result  in a change  of control in the  future upon subsequent
disposition. Additionally, the Company has  not  completed a Research and Development Credit Study,
accordingly it is probable that a portion  of the tax credit  carryforward may not be available  to  offset
future income. During fiscal year 2015, the Company  completed a  study  to  assess whether a change of
control has occurred or whether there have been  multiple changes  of  control  since its formation.  The
study was performed in anticipation  of  the Royalty Obligation transaction being completed (see

108

IMMUNOGEN, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

AS OF JUNE 30, 2015

F.

Income Taxes (Continued)

Note E), as that transaction for tax purposes is considered  a  gain on the sale of royalties and is  taxable
in the year it occurs. The result of the  study indicated  that  the Company  would be able  to  utilize its
NOL’s to fully offset the taxable income  that resulted  from  the royalty  transaction. Accordingly, there  is
no provision for income taxes in the current  year.

Interest and penalties related to the settlement of uncertain tax positions, if any,  will  be  reflected

in income tax expense. The Company  did  not recognize  any interest and penalties associated with
unrecognized tax benefits in the accompanying consolidated  financial  statements. The Company  does
not expect any material changes to the unrecognized benefits within 12 months of  the reporting date.
Due to existence of the valuation allowance,  future changes in the Company’s unrecognized tax benefits
will not impact our effective tax rate. The  Company’s loss  and credit carryforwards are subject to
adjustment by state and federal taxing  authorities, commencing  when those losses are utilized  to  reduce
taxable income.

G. Capital Stock

Common Stock Reserved

At June  30, 2015, the Company has reserved 16.2 million shares of authorized common stock for

the future issuance of shares under the 2006 Plan and the 2004 Director Plan. See  ‘‘Stock-Based
Compensation’’ in Note B for a description of the 2006 Plan and the Former Plan  and Note G below
for a description of the 2004 Director Plan.

Stock Options

As of June 30, 2015, the 2006 Plan was the only employee share-based compensation plan  of  the

Company. During the year ended June 30,  2015, holders of  options  issued under the 2006  Plan  and the
Former Plan exercised their rights to acquire  an aggregate  of  651,000 shares  of  common stock at  prices
ranging from $3.19 to $10.89 per share. The  total  proceeds  to  the  Company from these option exercises
were approximately $4.4 million.

The Company granted options with an exercise price equal to the fair  market  value of  the common

stock on the date of such grant. The  following  options  and their respective  weighted-average exercise
prices per share were exercisable at June  30, 2015, 2014 and 2013:

Exercisable
(in thousands)

Weighted-
Average
Exercise Price

June 30, 2015 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
June 30, 2014 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
June 30, 2013 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5,380
4,637
4,202

$11.89
$ 9.79
$ 7.97

2001 Non-Employee Director Stock Plan

In November 2001, the Company’s shareholders approved the  establishment of the  2001

Non-Employee Director Stock Plan,  or the 2001  Director Plan, and  50,000 shares of common stock to
be reserved for grant thereunder. The 2001 Director Plan provided for  the  granting of awards to

109

IMMUNOGEN, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

AS OF JUNE 30, 2015

G. Capital Stock (Continued)

Non-Employee Directors and, at the election of Non-Employee Directors, to have all or  a portion of
their awards in the form of cash, stock,  or stock  units. All stock  or  stock units are  immediately vested.
The number of stock or stock units issued was determined by  the market value  of  the Company’s
common stock on the last date of the  Company’s fiscal quarter for  which the services are  rendered.
The 2001 Director Plan was administered  by the Board  of  Directors which was authorized to interpret
the provisions of the 2001 Director Plan,  determine which  Non-Employee  Directors would  be  granted
awards, and determine the number of  shares of  stock  for  which a stock right will be granted. The 2001
Director Plan was replaced in 2004 by  the 2004  Non-Employee  Director Compensation and Deferred
Share Unit Plan.

During  the years ended June 30, 2015, 2014 and 2013, the  Company recorded approximately
$16,000, $(30,000), and $(1,000) in compensation  expense (expense reduction), respectively,  related to
approximately 6,000 stock units outstanding under  the 2001 Director  Plan. The value  of the stock units
is adjusted to market value at each reporting period.  No stock  units  have been issued under  the 2001
Plan subsequent to June 30, 2004.

2004 Non-Employee Director Compensation  and Deferred  Share  Unit Plan

In June 2004, the Board of Directors approved the establishment of the  2004 Non-Employee
Director Compensation and Deferred Share  Unit Plan, or the 2004 Director  Plan.  The  2004 Director
Plan provided for the compensation  of  Non-Employee  Directors, awarding  their annual retainers in the
form of deferred share units, and, at their  discretion, to have  all or a  portion  of their  other
compensation such as meeting fees in the  form of cash or deferred share units. The deferred  share
units for annual retainers vested one-twelfth monthly over the  next year  after the award; other deferred
share units vested  immediately upon issuance.  The  number of deferred share units issued  was
determined by the  market value of the Company’s common stock on the last  date of the  Company’s
fiscal year prior to the fiscal year for  which services were rendered.  The  deferred share  units were to be
paid out in cash to each non-employee director based upon the market value of the  Company’s
common stock on the date of such director’s retirement  from the Board  of Directors  of  the Company.
The 2004 Director Plan was administered  by the Board  of  Directors.

The 2004 Director Plan was amended on September 5, 2006. Under the terms of the amended

2004 Director Plan, the redemption amount of deferred  share units will  be  paid in shares of common
stock of the Company under the 2006  Plan in lieu of cash. As  a  result of  the  change  in payout
structure, the value of the vested awards was transferred to  additional paid-in capital  as of the
modification date and the total value of  the awards, as calculated on the modification date,  was
expensed over the remainder of the vesting period. Accordingly,  the value of the share units is fixed
and will no longer be adjusted to market value at each reporting  period. In addition, the amended 2004
Director Plan changed the vesting for annual retainers to take  place quarterly  over the three years after
the award and the number of deferred  share units  awarded  for all compensation is now  based on the
market value  of the Company’s common  stock on the  date of the award.

Compensation Policy for Non-Employee Directors

On September 16, 2009, the Board adopted  a new  Compensation Policy  for  Non-Employee
Directors, which superseded the 2004 Plan and made  certain changes to the compensation  of  its

110

IMMUNOGEN, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

AS OF JUNE 30, 2015

G. Capital Stock (Continued)

non-employee directors. The policy was  amended  on November  11, 2009  to  provide that, whenever  the
Board has a non-employee Chairman  in lieu of a Lead Director, the  cash payment for the
non-employee Chairman of the Board shall be the same  as the cash compensation that would  otherwise
have been payable to the Lead Director. Effective November 12, 2009, non-employee directors became
entitled to receive annual meeting fees  and committee fees under  the new  policy. The  new policy made
changes to the equity portion of the  non-employee director  compensation,  but left  the cash  portion
unchanged. Effective November 11, 2009,  non-employee directors became entitled to receive deferred
stock units under the new policy as follows:

(cid:129) New non-employee directors will be initially awarded a  number  of deferred stock units having  an
aggregate market value of $65,000, based on the  closing  price of our common stock on the date
of their initial election to the Board.  These awards  will vest quarterly over three years from  the
date  of grant, contingent upon the individual  remaining  a director  of ImmunoGen as of each
vesting date.

(cid:129) On the first anniversary of a non-employee  director’s initial  election to the Board, such

non-employee director will be awarded  a number  of deferred  stock  units  having an aggregate
market value of $30,000, based on the closing price  of our common stock on  such date of grant
and pro-rated based on the number of whole months remaining  between the first day of the
month in  which such grant date occurs and the  first October  31 following the grant date. These
awards will generally vest quarterly over  approximately the  period from  the grant date  to  the
first November 1 following the grant date, contingent upon the individual remaining a  director
of ImmunoGen as of each vesting date.

(cid:129) Thereafter, non-employee directors  in general will be annually awarded a  number of  deferred
stock units having an aggregate market  value of $30,000, based on the  closing  price of our
common stock on the date of our annual meeting of shareholders.  These  awards will vest
quarterly over approximately one year from the date  of  grant, contingent upon the individual
remaining a director of ImmunoGen  as of each vesting  date.

As with the 2004 Plan, vested deferred stock units are redeemed on the date a director  ceases  to
be a member of the Board, at which time  such director’s deferred  stock units will be settled in shares
of our common stock issued under our  2006 Plan at a rate of  one  share for each vested deferred  stock
unit then held. Any deferred stock units that remain unvested  at that time will  be  forfeited. The new
policy provides that all unvested deferred  stock units will  automatically  vest immediately prior to the
occurrence of a change of control, as defined  in the 2006 Plan. Pursuant to the  Compensation Policy
for Non-Employee Directors, the Company issued a retiring director 43,615 shares  of common stock in
November 2013.

In connection with the adoption of the  new  compensation  policy, the  Board also  amended the

2004 Plan as follows:

(cid:129) All unvested deferred stock awards (other than any  unvested initial  awards) were  vested in full

on September 16,  2009 unless the date such deferred stock units were credited to the
non-employee director was less than  one  year prior to September 16, 2009, in  which case such
unvested deferred stock units will vest on the first anniversary of the date  such deferred  stock
units were credited to the non-employee director.

111

IMMUNOGEN, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

AS OF JUNE 30, 2015

G. Capital Stock (Continued)

(cid:129) All unvested deferred stock awards will automatically vest immediately  prior to the  occurrence

of a change of control.

On September 22, 2010, the Board revised the Compensation  Policy for  Non-Employee Directors

to provide that, in addition to the compensation  they received previously, they would also  become
entitled to receive stock option awards  having  a grant date fair value of  $30,000, determined using  the
Black-Scholes option pricing model measured on  the date  of grant, which would be the date of the
annual meeting of shareholders.

On November 12, 2013, the Board amended the Compensation Policy for Non-Employee Directors

to make certain changes to the compensation  of  its  non-employee  directors,  including an  increase in
the fees paid in cash to the non-employee  directors. Under  the terms  of  the amended  policy, the
redemption amount of deferred share  units issued  will continue to be paid in shares of  common stock
of the Company on the date a director ceases to be a member of the Board. Annual retainers vest
quarterly over approximately one year from the date  of  grant, contingent upon the individual  remaining
a director of ImmunoGen as of each vesting date. The  number of deferred share  units awarded is  now
fixed per the plan on the date of the award and is no  longer  based on the  market  price of the
Company’s common stock on the date  of the  award. All unvested deferred stock awards  will
automatically vest immediately prior  to  the occurrence of a  change of control.

In addition to the deferred share units,  the Non-Employee Directors are now also entitled to
receive a fixed number of stock options instead of a fixed grant date  fair value of options, determined
using the Black-Scholes option pricing model measured on the date of grant, which would be the  date
of the annual meeting of shareholders. These options vest quarterly over approximately  one year  from
the date of grant. Any new directors will  receive a pro-rated award, depending  on their date of election
to the Board. The directors received a  total of 80,000, 80,000 and 41,805 options in fiscal years ended
2015, 2014 and 2013, respectively, and  the related compensation expense  is included in the amounts
discussed in the ‘‘Stock-Based Compensation’’  section  of  footnote  B above.

Pursuant to the Compensation Policy for Non-Employee Directors, as amended, the Company

recorded  approximately:

(cid:129) $389,000 in compensation expense during the year ended  June  30, 2015 related to the grant of

31,000 deferred share units and 15,000 deferred  share units previously granted;

(cid:129) $433,000 in compensation expense during the year ended  June  30, 2014 related to the grant of

28,000 deferred share units and 19,000 deferred  share units previously granted; and

(cid:129) $351,000 in compensation expense during the year ended  June  30, 2013 related to the grant of

26,000 deferred share units and 21,000 deferred  share units previously granted.

H. Commitments and Contingencies

Leases

Effective July 27, 2007, the Company  entered into a lease agreement with Intercontinental

Fund III for the rental of approximately 89,000 square feet of laboratory  and office space  at 830  Winter
Street, Waltham, MA through March  2020. The  Company uses this space for its corporate  headquarters

112

IMMUNOGEN, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

AS OF JUNE 30, 2015

H. Commitments and Contingencies (Continued)

and other operations. In December 2013,  the Company modified  its lease agreement  at 830  Winter
Street, Waltham, MA to include approximately 19,000  square feet of additional office space through
2020, concurrent with the remainder  of the original lease term. As  part  of  the lease amendment, the
Company received a construction allowance of approximately $746,000 to build out office space  to  the
Company’s specifications. The Company obtained physical control  of the additional space  to  begin
construction in January 2014. In April,  2014, the  Company again modified its lease  agreement at this
site to extend the lease to 2026. The Company may extend the lease for two  additional terms of five
years. As part of this lease amendment, the  Company received a  construction allowance of
approximately $1.1 million to build out  office space to the Company’s specifications. The Company  is
required to pay certain operating expenses for the leased premises subject to escalation charges for
certain expense increases over a base amount.  The Company entered  into  a sublease in December 2009
for 14,100 square feet of this space in  Waltham  through January 2015; however, the Company  and the
sublessee agreed to end the lease term effective December 31, 2014.

Effective April 2012, the Company entered into a  sublease agreement for the rental of 7,310

square  feet of laboratory and office space  at 830 Winter Street, Waltham,  MA from Histogenics
Corporation, the term of which expired  in May 2015.

The Company also leases manufacturing and  office space at 333 Providence Highway,

Norwood, MA under an agreement through 2018 with an option to extend  the lease for an additional
term of five years. The Company is required to pay certain  operating expenses for  the leased  premises
subject to escalation charges for certain expense increases over a base amount.

Effective April 2013, the Company entered into a  lease agreement with River Ridge  Limited

Partnership for the rental of 7,507 square  feet of additional  office space at 100 River Ridge Drive,
Norwood, MA. The initial term of the lease was for five years and two months commencing in  July
2013 with an option for the Company to extend the lease for an additional term of  five years. The
Company is required to pay certain operating expenses for the leased premises subject to escalation
charges for certain expense increases  over  a base amount. The  Company entered into a  sublease in
December 2014 for this space, effective  January 2015 through  the remaining initial term of the lease.

Facilities rent expense, net of sublease income, was  approximately  $6.0 million,  $5.4 million and

$4.8 million during fiscal years 2015,  2014 and  2013, respectively.

113

IMMUNOGEN, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

AS OF JUNE 30, 2015

H. Commitments and Contingencies (Continued)

As of June 30, 2015, the minimum rental commitments, including real estate  taxes and  other

expenses, for the next five fiscal years  and  thereafter under the non-cancelable operating  lease
agreements discussed above are as follows  (in thousands):

2016 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2017 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2018 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2019 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2020 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Thereafter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

$ 7,130
7,147
7,253
6,441
6,424
38,857

Total minimum lease payments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Total minimum rental income from subleases . . . . . . . . . . . . . . . . . . . . . .

$73,252
(370)

Total minimum lease payments, net . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

$72,882

There are no obligations under capital leases as of June 30, 2015, as all of the  capital leases were

single payment obligations which have all been made.

Collaborations

The Company is contractually obligated to make potential future  success-based regulatory
milestone payments in conjunction with certain  collaborative agreements. These payments are
contingent upon the occurrence of certain future events  and, given  the nature of these events,  it is
unclear when, if ever, the Company may be required to pay such  amounts.  Further, the timing of any
future payment is not reasonably estimable. As of  June 30, 2014, the maximum amount that may be
payable in the future under the Company’s current  collaborative agreements is  $162 million,
$1.4 million of which is reimbursable  by a  third party under a  separate agreement.

Litigation

The Company is not party to any material litigation.

I. Employee Benefit Plans

The Company has a deferred compensation  plan under Section 401(k) of the Internal Revenue
Code (the 401(k) Plan). Under the 401(k)  Plan, eligible employees are permitted to contribute, subject
to certain limitations, up to 100% of their  gross salary  and the  Company’s matching  contribution is
50% of the first 6% of the eligible employees’ contributions. In  fiscal years  2015, 2014 and 2013,  the
Company’s contributions to the 401(k)  Plan totaled  approximately  $875,000, $710,000, and $593,000,
respectively.

114

IMMUNOGEN, INC.

NOTES TO CONSOLIDATED FINANCIAL  STATEMENTS (Continued)

AS OF JUNE 30, 2015

J. Quarterly Financial Information (Unaudited)

Revenues:

License and milestone fees . . . . . .
Royalty revenue . . . . . . . . . . . . . .
Non-cash royalty revenue related

to the sale of future royalties . . .
Research and development support
Clinical materials revenue . . . . . . .

Total revenues . . . . . . . . . . . . .

Expenses:

Research and development . . . . . .
General and administrative . . . . . .

Total expenses . . . . . . . . . . . . .

Fiscal Year 2015

First Quarter
Ended
September 30, 2014

Second Quarter
Ended

Third Quarter
Ended

December 31, 2014 March 31,  2015

Fourth Quarter
Ended
June 30,  2015

(In thousands, except per share data)

$ 6,234
4,166

$41,417
4,625

$ 5,078
5,099

$ 5,086
(23)

—
776
2,027

13,203

28,018
7,095

35,113

—
832
1,426

48,300

27,647
6,872

34,519

13,781

—
532
718

11,427

25,666
7,000

32,666

5,484
708
1,356

12,611

30,437
7,261

37,698

(21,239)

(25,087)

(Loss) income from operations . . . . .

(21,910)

Non-cash interest expense on

liability related to sale of future
royalty . . . . . . . . . . . . . . . . . . .
Other (expense) income, net . . . . .

—
(372)

—
(146)

—
(379)

(5,437)
50

Net (loss) income . . . . . . . . . . . . . .

$(22,282)

$13,635

$(21,618)

$(30,474)

Basic and diluted net (loss)

income per common share . . . . .

$

(0.26)

$

0.16

$

(0.25)

$

(0.35)

115

IMMUNOGEN, INC.

NOTES TO CONSOLIDATED FINANCIAL  STATEMENTS (Continued)

AS OF JUNE 30, 2015

J. Quarterly Financial Information (Unaudited) (Continued)

Fiscal Year 2014

First Quarter
Ended
September 30, 2013

Second Quarter
Ended

Third Quarter
Ended

December 31, 2013 March 31,  2014

Fourth Quarter
Ended
June 30,  2014

(In thousands, except per share data)

Revenues:

License and milestone fees . . . . . .
Royalty revenue . . . . . . . . . . . . . .
Research and development support
Clinical materials revenue . . . . . . .

Total revenues . . . . . . . . . . . . .

Expenses:

Research and development . . . . . .
General and administrative . . . . . .

Total expenses . . . . . . . . . . . . .

(Loss) income from operations . . . . .
Other income (expense), net . . . . .

$ 13,167
2,053
1,990
8

17,218

22,029
6,526

28,555

(11,337)
111

$25,678
2,335
1,922
125

30,060

20,862
5,447

26,309

3,751
62

$

305
2,558
1,948
2,064

6,875

38,280
6,040

44,320

(37,445)
(7)

$

305
3,400
1,327
711

5,743

25,787
6,456

32,243

(26,500)
1

Net (loss) income . . . . . . . . . . . . . .

$(11,226)

$ 3,813

$(37,452)

$(26,499)

Basic and diluted net (loss)

income per common share . . . . .

$

(0.13)

$

0.04

$

(0.44)

$

(0.31)

116

Item 9. Changes in and Disagreements with Accountants  on Accounting and Financial Disclosure

None.

Item 9A. Controls and Procedures

1. Disclosure Controls and Procedures

Our management, with the participation of our principal executive officer and principal financial

officer, has evaluated the effectiveness  of  our disclosure controls and procedures (as defined in
Rules 13a-15(e) or 15d-15(e) under the Securities Exchange  Act of  1934, as amended) as of the  end of
the period covered by this Annual Report  on Form 10-K. Based on such evaluation,  our principal
executive officer and principal financial officer have  concluded that,  as of the  end of such  period, our
disclosure controls and procedures were  adequate and effective.

2.

Internal Control Over Financial Reporting

(a) Management’s Annual Report on  Internal  Control  Over  Financial  Reporting

Our management is responsible for establishing and maintaining adequate internal  control over
financial reporting. Internal control over financial reporting is defined in Rules  13a-15(f) and 15d-15(f)
under the Exchange Act as a process  designed by, or under the supervision  of, our  principal executive
and principal financial officers and effected by our  board  of directors, management and  other
personnel to provide reasonable assurance regarding the reliability of  financial  reporting and  the
preparation of financial statements for external purposes in  accordance with generally  accepted
accounting principles in the U.S. and  includes those policies and procedures that:

(cid:129) pertain to the maintenance of records that in reasonable detail accurately and fairly  reflect our

transactions and dispositions of our assets;

(cid:129) provide reasonable assurance that transactions are recorded  as necessary to permit preparation

of financial statements in accordance with generally accepted  accounting principles, and  that  our
receipts  and expenditures are being made  only  in accordance with authorizations of our
management and directors; and

(cid:129) provide reasonable assurance regarding prevention or timely detection of  unauthorized

acquisition, use or  disposition of our assets  that could  have a material  effect  on the financial
statements.

Because of its inherent limitations, internal control over  financial  reporting may not prevent or
detect misstatements. Projections of any  evaluation of effectiveness to future periods are subject  to  the
risks that controls may become inadequate because of changes  in conditions, or that the  degree  of
compliance with the policies or procedures may deteriorate.

Management assessed the effectiveness of our internal control over financial  reporting as of

June 30, 2015. In making this assessment,  management  used  the criteria established in Internal
Control—Integrated Framework issued by the Committee of Sponsoring Organizations of the Treadway
Commission, or COSO, in 2013.

Based on this assessment, management has concluded that, as of  June  30, 2015 our internal control

over financial reporting is effective.

Ernst & Young LLP, our independent registered public accounting firm,  has issued a report  on the

effectiveness of our internal control over  financial reporting  as of June 30,  2015. This  report appears
immediately below.

117

(b) Attestation Report of the Independent Registered  Public  Accounting Firm

Report of Independent Registered Public Accounting Firm

The Board of Directors and Shareholders  of ImmunoGen, Inc.

We  have audited ImmunoGen, Inc.’s internal control over financial  reporting  as of June 30, 2015,

based on criteria established in Internal Control—Integrated  Framework issued by the  Committee of
Sponsoring Organizations of the Treadway Commission (2013 framework)(the  COSO criteria).
ImmunoGen, Inc.’s management is responsible  for maintaining effective internal control over financial
reporting, and for its assessment of the  effectiveness  of  internal control  over financial reporting
included in the accompanying Management’s  Annual  Report on Internal Control  Over  Financial
Reporting. Our responsibility is to express an  opinion on  the company’s internal control over financial
reporting based on our audit.

We  conducted our audit in accordance with the standards of  the Public Company Accounting
Oversight Board (United States). Those  standards require that we  plan and perform the audit to obtain
reasonable assurance about whether  effective  internal control over financial reporting was maintained
in all material respects. Our audit included  obtaining an understanding  of internal control  over
financial reporting, assessing the risk that a  material weakness exists, testing and evaluating the design
and operating effectiveness of internal control based  on the assessed risk, and performing such other
procedures as we considered necessary in  the circumstances. We believe that our audit  provides a
reasonable basis for our opinion.

A company’s internal control over financial reporting is a process designed to provide  reasonable

assurance regarding the reliability of  financial  reporting and the preparation  of  financial  statements  for
external  purposes in accordance with  generally accepted accounting  principles. A company’s internal
control over financial reporting includes those policies and procedures that (1) pertain to the
maintenance of records that, in reasonable  detail, accurately and fairly reflect the  transactions and
dispositions of the assets of the company; (2) provide reasonable assurance that transactions  are
recorded  as necessary to permit preparation of financial statements in  accordance with generally
accepted accounting principles, and that receipts and expenditures of the company are being made  only
in accordance with authorizations of management and directors of the company; and  (3) provide
reasonable assurance regarding prevention  or timely detection of unauthorized acquisition, use, or
disposition of the company’s assets that  could have a material effect on the financial statements.

Because of its inherent limitations, internal control over  financial  reporting may not prevent or

detect misstatements. Also, projections  of any evaluation  of  effectiveness to future periods are  subject
to the risk that controls may become inadequate  because of changes in conditions, or  that  the degree
of compliance with the policies or procedures may deteriorate.

In our opinion, ImmunoGen, Inc. maintained,  in all material  respects, effective internal  control

over financial reporting as of June 30, 2015, based on the COSO criteria.

We  also have audited, in accordance  with the standards of  the Public Company Accounting
Oversight Board (United States), the  consolidated balance sheets of ImmunoGen, Inc. as  of  June 30,
2015 and 2014, and the related consolidated  statements  of operations  and  comprehensive loss,
shareholders’ equity and cash flows for  each of the three years  in the  period ended  June 30,  2015 and
our  report dated August 27, 2015 expressed an unqualified opinion thereon.

/s/ Ernst & Young LLP

Boston, Massachusetts
August 27, 2015

118

(c) Changes in Internal Control Over  Financial Reporting

There have not been any changes in our internal control  over  financial reporting (as such term is
defined in Rules 13a-15(f) and 15d-15(f)  under the  Exchange Act) during the  quarter  ended June 30,
2015 that have materially affected, or  are  reasonably likely to materially affect, our internal  control
over financial reporting.

3. Limitations on the Effectiveness of  Controls

Our management, including our principal  executive officer and principal financial officer, does  not

expect that our disclosure controls and  procedures or its  internal control  over financial reporting will
prevent all error and all fraud. A control  system,  no matter  how  well conceived and operated, can
provide only reasonable, not absolute,  assurance that the objectives of the  control system are  met.
Further, the design of a control system must reflect  the fact that there are resource constraints, and  the
benefits of controls must be considered relative to their costs. Because  of the inherent  limitations in all
control systems, no evaluation of controls can  provide absolute assurance  that  all  control issues  and
instances of fraud, if any, within an organization have been detected. These inherent limitations include
the realities that judgments in decision-making can be faulty,  and that breakdowns can  occur because of
simple error or mistake.

Additionally, controls can be circumvented by the  individual acts of some  persons, by collusion of
two or more people, or by management override of  the control. The design  of  any system of controls
also is based in part upon certain assumptions about  the likelihood of future events,  and there  can be
no assurance that any design will succeed in achieving  our stated  goals under all potential future
conditions. Over time, controls may become inadequate  because of changes  in conditions, or  the degree
of compliance with the policies or procedures may deteriorate. Because of  the inherent limitations in a
cost-effective control system, misstatements due to error or fraud may occur and  not  be  detected.

Item 9B. Other Information

None.

119

PART III

The information called for by Part III of Form 10-K  (Item 10—Directors, Executive Officers and

Corporate Governance of the Registrant,  Item  11—Executive Compensation, Item  12—Security
Ownership of Certain Beneficial Owners  and Management  and  Related  Stockholder  Matters, Item 13—
Certain Relationships and Related Transactions, and Director Independence, and Item 14—Principal
Accounting Fees and Services) is incorporated by reference  from our proxy statement related to our
2015 annual meeting of shareholders,  which will be filed  with the  Securities  and Exchange  Commission
not later than October 28, 2015 (120 days after the  end of the fiscal year covered by this Annual
Report on Form 10-K), except that information required by Item 10  concerning our executive officers
appears  in Part I, Item 3.1 of this Annual  Report  on Form 10-K.

120

Item 15. Exhibits, Financial Statement Schedules

(a) Financial Statements:

PART IV

(1) See ‘‘Index to Consolidated Financial Statements’’  at Item  8 of this Annual  Report on

Form 10-K. Schedules not included herein are omitted  because they  are  not applicable or  the
required information appears in the accompanying Consolidated Financial  Statements or Notes
thereto.

(2) See Exhibit Index following the  signature page  to  this  Annual  Report on  Form  10-K.

121

Pursuant to the requirements of Section  13 or 15(d)  of  the Securities Exchange Act  of 1934, the

Registrant has duly caused this report to be signed  on its behalf  by the undersigned,  thereunto duly
authorized.

SIGNATURES

IMMUNOGEN, INC.

By:

/s/ DANIEL M. JUNIUS

Daniel M. Junius
President and
Chief Executive Officer
(Principal Executive Officer)

Dated: August 27, 2015

Pursuant to the requirements of the Securities Exchange Act of 1934,  this report has been signed

below by the following persons on behalf of  the Registrant  in the capacities  and on the dates indicated.

Signature

Title

Date

/s/ DANIEL M. JUNIUS

Daniel M. Junius

/s/ DAVID B. JOHNSTON

David B. Johnston

/s/ STEPHEN MCCLUSKI

Stephen McCluski

/s/ MARK GOLDBERG, M.D.

Mark Goldberg, M.D.

/s/ DEAN MITCHELL

Dean Mitchell

/s/ NICOLE ONETTO, M.D.

Nicole Onetto, M.D.

/s/ KRISTINE PETERSON

Kristine Peterson

/s/ HOWARD PIEN

Howard Pien

/s/ JOSEPH VILLAFRANCA PH.D.

Joseph  Villafranca, Ph.D.

/s/ RICHARD WALLACE

Richard Wallace

President, Chief Executive Officer and Director
(Principal Executive Officer)

August 27, 2015

Executive Vice President and
Chief Financial Officer
(Principal Financial and Accounting Officer)

August  27, 2015

Chairman of the Board of Directors

August  27, 2015

Director

August 27, 2015

Director

August 27, 2015

Director

August 27, 2015

Director

August 27, 2015

Director

August 27, 2015

Director

August 27, 2015

Director

August 27, 2015

122

EXHIBIT INDEX

Filed
with this
Form 10-K Form

Incorporated by Reference

Filing Date
with SEC

Exhibit
Number

10-Q

10-Q

8-K

S-1

S-1

April  30, 2010

January 30,  2013

April 6,  2007

November  15, 1989
(File No.  33-31219)

3.1

3.1

3.1

4.2

September  22,  1989
(File No. 33-31219)

10.10

S-1

November  6,  1991
(File  No. 33-43725)

10.10a

10-K September  26, 1997

10.10

10-K

September 2,  2008

10.1(c)

10-K

September 2,  2008

10.1(d)

10-K

September 2,  2008

10.1(e)

10-K

September 2,  2008

10.1(f)

10-K

September 2,  2008

10.1(g)

10-K

September 2,  2008

10.1(h)

Exhibit
Number

Exhibit Description

3.1

Restated Articles of Organization, as  amended

3.1(a)

Articles of Amendment

3.2

4.1

4.2

10.1

10.1(a)

10.1(b)

10.1(c)

10.1(d)

10.1(e)

10.1(f)

10.1(g)

10.1(h)

Amended and Restated By-Laws

Article 4 of Restated Articles of Organization,  as
amended (see Exhibit 3.1)

Form of Common Stock certificate

Leases dated as of December 1, 1986  and June 21,
1988 by and between James H. Mitchell, Trustee
of New Providence Realty Trust, lessor, and
Charles River Biotechnical Services, Inc.
(‘‘Lessee’’), together with Assignment of Leases
dated June 29, 1989 between Lessee  and  the
Registrant

First Amendment to Lease dated May  9, 1991 by
and between James H. Mitchell, Trustee of New
Providence Realty Trust, lessor, and the  Registrant

Confirmatory Second Amendment to Lease dated
September 17, 1997 by and between James H.
Mitchell, Trustee of New Providence Realty Trust,
lessor, and the Registrant

Third Amendment and Partial  Termination  of
Lease dated as of August 8, 2000 by and between
James H. Mitchell, Trustee of New Providence
Realty Trust, lessor, and the Registrant

Fourth Amendment to Lease  dated  as of
October 3, 2000 by and  between James  H.
Mitchell, Trustee of New Providence Realty Trust,
lessor, and the Registrant

Fifth Amendment to Lease dated as of  June  7,
2001 by and between James H. Mitchell, Trustee
of New Providence Realty Trust, lessor, and  the
Registrant

Sixth  Amendment to Lease dated as  of  April 30,
2002 by and between Bobson 333 L.L.C.,  lessor,
and the Registrant

Seventh Amendment to Lease dated  as  of
October 20, 2005 by and  between Bobson  333
L.L.C., lessor, and  the Registrant

Eighth Amendment to Lease dated as  of
February 21, 2007 by and between Bobson 333
L.L.C., lessor, and  the Registrant

123

Exhibit
Number

10.1(i)

10.2

10.2(a)

10.2(b)

Exhibit Description

Ninth Amendment to Lease dated  as  of
November 17, 2010 by and between Bobson
333 LLC and the Registrant

Lease Agreement, dated as  of July  27,  2007, by
and between Intercontinental Fund  III 830  Winter
Street LLC, landlord, and the Registrant

First Amendment to Lease Agreement  dated  as  of
December 9, 2013, by and between
Intercontinental Fund III 830 Winter Street LLC,
landlord, and the Registrant

Second Amendment to Lease Agreement  dated as
of April 28, 2014, by and between  Intercontinental
Fund III 830 Winter Street LLC, landlord,  and  the
Registrant

Filed
with this
Form 10-K Form

Incorporated by Reference

Filing Date
with SEC

Exhibit
Number

8-K

November  18,  2010

10.1

10-Q

November  7,  2007

10.2

10-Q

February  5,  2014

10.1

10-Q

May  2, 2014

10.1

10.3*

License Agreement dated  effective  May 2,  2000 by
and between the  Registrant and Genentech, Inc.

10-Q

October 31,  2011

10.1

10.3(a)* Amendment  to License Agreement  for Anti-HER2

10-K

August  28, 2006

10.32

Antibodies, dated as of May 3, 2006, between the
Registrant and Genentech, Inc.

10.3(b)* Amendment  to License Agreements  made  effective

10-Q

May  7, 2009

10.1

10.3(c)

10.4*

10.4(a)

10.4(b)

10.4(c)

10.5*

as of March 11, 2009, between  the  Registrant and
Genentech, Inc.

Third Amendment to License Agreement for
Anti-HER2 Antibodies, made effective as of
December 18, 2012, between the Registrant and
Genentech, Inc.

Collaboration and License Agreement dated as  of
July 30, 2003 by and between the Registrant and
sanofi-aventis U.S. LLC (as successor-in-interest  to
Aventis Pharmaceuticals Inc.)

Amendment  No. 1, dated as  of August  31, 2006, to
the Collaboration and License Agreement between
the Registrant and sanofi-aventis U.S. LLC

Amendment  No. 2, dated as  of December 7,  2007,
to the Collaboration and License Agreement
between the Registrant  and sanofi-aventis
U.S. LLC

Amendment  No. 3, dated as  of August  31, 2008, to
the Collaboration and License Agreement between
the Registrant and sanofi-aventis U.S. LLC

Option and License Agreement dated  as of
December 21, 2006 by and between the Registrant
and sanofi-aventis U.S. LLC

124

10-Q

January 30,  2013

10.11

10-K

August  28, 2014

10.4

10-Q

October  30,  2014

10.4

10-Q

October 30,  2014

10.5

10-Q

October  30,  2014

10.6

10-Q

February 8,  2007

10.2

Exhibit
Number

10.6*

Exhibit Description

Collaborative Development and License
Agreement dated as of  July 7, 2006 by and
between the Registrant  and Biotest  AG

Filed
with this
Form 10-K Form

Incorporated by Reference

Filing Date
with SEC

Exhibit
Number

10-Q

November  3,  2006

10.2

10.6(a)* Amendment  No. 1, dated August 23, 2006, to

10-Q

November  3,  2006

10.3

Collaborative Development and License
Agreement by and  between the Registrant and
Biotest AG

10.6(b)* Amendment  No. 2, dated December 10,  2014,  to

10-Q

February  5,  2015

10.1

Collaborative Development and License
Agreement by and  between the Registrant and
Biotest AG

Development and License Agreement dated  as  of
October 20, 2008 by and  between the Registrant
and Bayer HealthCare AG

Multi-Target Agreement dated as  of  October 8,
2010 by and between the Registrant  and Novartis
Institutes for BioMedical Research, Inc.

First Amendment, effective as of  March  29, 2013,
to Multi-Target Agreement by and  between  the
Registrant and Novartis  Institutes for  BioMedical
Research, Inc.

Clinical Supply Agreement effective  as  of
December 12, 2010 by and between the Registrant
and Societ´a Italiana Corticosteroidi  S.r.l.  (Sicor)

Multi-Target Agreement dated as  of  December  19,
2011 by and between the Registrant  and Eli Lilly
and Company

10.7*

10.8*

10.8(a)*

10.9*

10.10*

10-Q/A

October 10,  2012

10.1

10-Q/A

August  19,  2015

10.2

10-Q

May  6, 2013

10.1

10-Q

February 8,  2011

10.1

10-Q/A

August  19,  2015

10.3

10.10(a)* First Amendment to Agreements dated as  of

10-Q

February 5,  2014

10.2

10.11*

10.12*

December 9, 2013 by and between the  Registrant
and Eli Lilly and Company

Multi-Target Agreement dated as  of  March 20,
2015 by and between the Registrant  and
Millennium Pharmaceuticals, Inc.

Royalty Purchase Agreement dated  as of
March 24, 2015 by and among  the  Registrant,
Hurricane, LLC and Immunity  Royalty
Holdings, L.P.

10.13†

Restated Stock Option Plan

10.13(a)† Form of Incentive Stock Option Agreement

10.13(b)† Form of Non-Qualified Stock Option  Agreement

10.14†

2006 Employee, Director  and Consultant  Equity
Incentive Plan, as amended  and restated through
November 11, 2014

125

10-Q

May  8,  2015

10.1

10-Q

May  8,  2015

10.2

8-K

8-K

8-K

8-K

February  7, 2006

February 7,  2006

February 7,  2006

November  13,  2014

10.1

10.2

10.3

10.1

Exhibit
Number

Exhibit Description

Filed
with this
Form 10-K Form

Incorporated by Reference

Filing Date
with SEC

Exhibit
Number

10.14(a)† Form of Incentive Stock Option Agreement for

S-8

November  15,  2006

99.4

Executives

10.14(b)† Form of Non-Qualified Stock Option  Agreement

S-8

November  15,  2006

99.5

for Executives

10.14(c)† Form of Non-Qualified Stock Option  Agreement

10-Q

October 29,  2010

10.1

for Directors

10.14(d)† Form of Director Deferred  Stock  Unit  Agreement

10.14(e)† Form of Incentive Stock Option Agreement for  all

employees (including executives)

10.14(f)† Form of Non-Qualified Stock Option  Agreement
for all employees (including executives)

10-Q

10-K

October 29,  2010

10.1

August  29,  2012 10.14(g)

10-K

August  29, 2012 10.14(h)

10.14(g)† Form of Non-Qualified Stock Option  Agreement

10-K

August  29, 2012

10.14(i)

for Directors

10.14(h)† Form of Restricted Stock Agreement  for all
employees (including executives)

10.15†

2001 Non-Employee Director Stock Plan

10.16†

10.17†

10.18†

10.19†

10.20†

10.21†

10.22†

10.23†

10.24†

2004 Non-Employee Director Compensation and
Deferred Stock Unit Plan, as amended  on
September16, 2009

Form of Proprietary Information, Inventions  and
Competition Agreement between the Registrant
and each of its executive  officers

Change in Control Severance  Agreement  dated  as
of November 30, 2012 between the Registrant and
Craig Barrows

Change in Control Severance  Agreement  dated  as
of November 30, 2012 between the Registrant and
Daniel M. Junius

Change in Control Severance  Agreement  dated  as
of November 30, 2012 between the Registrant and
John M. Lambert

Change in Control Severance  Agreement  dated  as
of November 30, 2012 between the Registrant and
Charles Q. Morris

Change in Control Severance  Agreement  dated  as
of November 30, 2012 between the Registrant and
Peter Williams

Compensation  Policy for  Non-Employee Directors,
as amended through November  12,  2013

Employment offer  letter between the  Registrant
and Charles Q. Morris

126

S-8

November  21, 2012

99.1

S-8

December 18,  2001

10-Q

November  4, 2009

99

10.1

10-Q

February 8,  2007

10.15

10-Q

January  30,  2013

10.1

10-Q

January  30,  2013

10.2

10-Q

January  30,  2013

10.3

10-Q

January  30,  2013

10.4

10-Q

January  30,  2013

10.7

10-Q

February  5,  2014

10.3

10-Q

January  30,  2013

10.9

Exhibit
Number

10.25†

10.26†

Exhibit Description

Change in Control Severance  Agreement  dated  as
of December 30, 2013 between the  Registrant and
David B. Johnston

Change in Control Severance  Agreement  dated  as
of February 20, 2014  between the Registrant  and
Ellie Harrison

10.27†

Severance Plan for Vice Presidents and  Higher

10.28†

10.29†

10.30†

Letter Agreement between the Registrant  and
Charles Q. Morris

Employment offer  letter between the  Registrant
and Sandra E. Poole

Change in Control Severance  Agreement  dated  as
of September 15, 2014 between the Registrant and
Sandra E. Poole

10.31†

Summary of Annual Bonus  Program

10.30†

10.32†

Employment offer  letter between the  Registrant
and Richard J. Gregory

Change in Control Severance  Agreement  dated  as
of January 5, 2015 between the Registrant  and
Richard J. Gregory

21

23

31.1

31.2

32

Subsidiaries of the Registrant

Consent of Ernst & Young LLP

Certification of the Chief Executive  Officer
pursuant to Section 302 of the Sarbanes-Oxley  Act
of 2002

Certification of the Chief Financial Officer
pursuant to Section 302 of the Sarbanes-Oxley  Act
of 2002

Certifications of Chief Executive Officer  and  Chief
Financial Officer pursuant to Section  906 of  the
Sarbanes-Oxley Act of 2002

101.INS

XBRL Instance Document

101.SCH XBRL Taxonomy Extension  Schema

101.CAL XBRL Taxonomy Extension  Calculation  Linkbase

101.DEF XBRL Taxonomy Extension  Definition Linkbase

101.LAB XBRL Taxonomy Extension  Label Linkbase

101.PRE XBRL Taxonomy Extension  Presentation  Linkbase

Filed
with this
Form 10-K Form

Incorporated by Reference

Filing Date
with SEC

Exhibit
Number

10-Q

February  5,  2014

10.6

10-Q

May  2, 2014

10.3

8-K

8-K

September 18,  2014

September 30,  2014

10.1

10.1

10-Q

October 30,  2014

10.1

10-Q

October 30,  2014

10.2

8-K

November 13,  2014

10-Q

February  5,  2015

10.2

10.2

10-Q

February  5,  2015

10.3

X

X

X

X

X

X

X

X

X

X

X

*

†

Portions of this Exhibit were omitted, as  indicated by  [***],  and have been  filed  separately  with  the Secretary
of the Commission pursuant to the Registrant’s application requesting  confidential  treatment.

Exhibit is a management contract  or compensatory  plan,  contract  or  arrangement required  to  be  filed  as  an
exhibit to the annual report on Form  10-K.

127

EXHIBIT 31.1

CERTIFICATIONS UNDER SECTION 302

I, Daniel M. Junius, certify that:

1.

I have reviewed this Annual Report on Form  10-K of ImmunoGen, Inc.;

2. Based on my knowledge, this report does not contain any untrue statement  of  a material fact or

omit to state a material fact necessary  to  make the statements made,  in light  of the circumstances
under which such statements were made, not misleading  with respect to the period  covered by this
report;

3. Based on my knowledge, the financial statements, and  other financial  information included in  this
report, fairly present in all material respects  the financial condition, results of operations and  cash
flows of the registrant as of, and for, the  periods presented in  this report;

4. The registrant’s other certifying  officer(s) and I are responsible for establishing and maintaining
disclosure controls and procedures (as defined  in Exchange  Act Rules  13a-15(e) and 15d-15(e))
and internal control over financial reporting (as defined in  Exchange Act  Rules 13a-15(f) and
15d-15(f)) for the registrant and have:

a)

designed such disclosure controls and  procedures,  or caused such disclosure controls and
procedures to be designed under our  supervision, to ensure that material  information relating
to the registrant, including its consolidated  subsidiaries, is made  known to us by others within
those entities, particularly during the period in  which this report is being prepared;

b) designed such internal control over financial reporting, or caused such internal control over

financial reporting to be designed under our supervision,  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;

c)

evaluated the effectiveness of the registrant’s  disclosure controls and  procedures and
presented in this report our conclusions  about the effectiveness of the disclosure controls and
procedures, as of the end of the period covered  by this  report based on such evaluation; and

d) disclosed in this report any change  in the registrant’s internal control over  financial  reporting

that occurred during the registrant’s most recent fiscal quarter (the registrant’s fourth fiscal
quarter in the case of an annual report) that has materially  affected, or is reasonably likely to
materially affect, the registrant’s internal  control over financial reporting; and

5. The registrant’s other certifying  officer(s) and I have disclosed,  based on our  most recent

evaluation of internal control over financial reporting, to the registrant’s auditors and the audit
committee of the registrant’s board of directors (or persons performing the equivalent functions):

a)

b)

all significant deficiencies and material weaknesses  in the design  or  operation  of internal
control over financial reporting which are  reasonably likely  to  adversely affect  the registrant’s
ability to record, process, summarize and report  financial information; and

any fraud, whether or not material,  that involves management  or other employees who have a
significant role in the registrant’s  internal control over financial  reporting.

Date: August 27, 2015

/s/ DANIEL M. JUNIUS

Daniel M. Junius
President and Chief Executive Officer
(Principal Executive Officer)

EXHIBIT 31.2

CERTIFICATIONS UNDER SECTION 302

I, David B. Johnston, certify that:

1.

I have reviewed this Annual Report on Form  10-K of ImmunoGen, Inc.;

2. Based on my knowledge, this report does not contain any untrue statement  of  a material fact or

omit to state a material fact necessary  to  make the statements made,  in light  of the circumstances
under which such statements were made, not misleading  with respect to the period  covered by this
report;

3. Based on my knowledge, the financial statements, and  other financial  information included in  this
report, fairly present in all material respects  the financial condition, results of operations and  cash
flows of the registrant as of, and for, the  periods presented in  this report;

4. The registrant’s other certifying  officer(s) and I are responsible for establishing and maintaining
disclosure controls and procedures (as defined  in Exchange  Act Rules  13a-15(e) and 15d-15(e))
and internal control over financial reporting (as defined in  Exchange Act  Rules 13a-15(f) and
15d-15(f)) for the registrant and have:

a)

designed such disclosure controls and  procedures,  or caused such disclosure controls and
procedures to be designed under our  supervision, to ensure that material  information relating
to the registrant, including its consolidated  subsidiaries, is made  known to us by others within
those entities, particularly during the period in  which this report is being prepared;

b) designed such internal control over financial reporting, or caused such internal control over

financial reporting to be designed under our supervision,  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;

c)

evaluated the effectiveness of the registrant’s  disclosure controls and  procedures and
presented in this report our conclusions  about the effectiveness of the disclosure controls and
procedures, as of the end of the period covered  by this  report based on such evaluation; and

d) disclosed in this report any change  in the registrant’s internal control over  financial  reporting

that occurred during the registrant’s most recent fiscal quarter (the registrant’s fourth fiscal
quarter in the case of an annual report) that has materially  affected, or is reasonably likely to
materially affect, the registrant’s internal  control over financial reporting; and

5. The registrant’s other certifying  officer(s) and I have disclosed,  based on our  most recent

evaluation of internal control over financial reporting, to the registrant’s auditors and the audit
committee of the registrant’s board of directors (or persons performing the equivalent functions):

a)

b)

all significant deficiencies and material weaknesses  in the design  or  operation  of internal
control over financial reporting which are  reasonably likely  to  adversely affect  the registrant’s
ability to record, process, summarize and report  financial information; and

any fraud, whether or not material,  that involves management  or other employees who have a
significant role in the registrant’s  internal control over financial  reporting.

Date: August 27, 2015

/s/ DAVID B. JOHNSTON

David B. Johnston
Executive Vice President and Chief Financial Officer
(Principal Financial and Accounting Officer)

EXHIBIT 32

CERTIFICATIONS UNDER SECTION 906

Pursuant to section 906 of the Sarbanes-Oxley  Act of 2002  (subsections (a)  and (b) of

section 1350, chapter 63 of title 18, United States Code),  each of the undersigned officers of
ImmunoGen, Inc., a Massachusetts corporation (the ‘‘Company’’), does  hereby certify,  to  such officer’s
knowledge, that:

The Annual Report for the year ended June 30, 2015  (the  ‘‘Form 10- K’’) of the  Company fully

complies with the requirements of Section 13(a) or 15(d) of  the Securities Exchange Act of  1934, and
the information contained in the Form  10-K fairly  presents, in all material respects, the financial
condition and results of operations of  the Company.

Dated: August 27, 2015

/s/ DANIEL M. JUNIUS

Daniel M. Junius
President and Chief Executive Officer
(Principal Executive Officer)

Dated: August 27, 2015

/s/ DAVID B. JOHNSTON

David B. Johnston
Executive Vice President and Chief Financial  Officer
(Principal Financial and Accounting Officer)

A signed original of this written statement required  by  Section 906 has  been provided to the

Company and will be retained by the  Company and furnished to the  Securities and Exchange
Commission or its staff upon request.

IMMUNOGEN, INC.

Stock Price Performance Graph

The graph and table below compare the  annual  percentage change in our cumulative total

shareholder return on our common stock  for the period from June 30,  2010 through June 30,  2015 (as
measured by dividing (i) the sum of (A)  the  cumulative amount of dividends for  the measurement
period, assuming dividend reinvestment,  and (B) the difference between  our share price at the end  and
the beginning of the measurement period;  by  (ii) the  share  price at the beginning of the measurement
period) with the total cumulative return of the NASDAQ Stock Market Index (U.S.) and the NASDAQ
Pharmaceutical Stocks Total Return Index during such period. We have not paid any dividends on  our
common stock, and no dividends are included in the  representation of our performance.  The  stock
price performance on the graph below  is  not necessarily indicative of future price performance. This
graph is not ‘‘soliciting material,’’ is not  deemed filed with  the Commission  and is not to be
incorporated by reference in any of our  filings under the Securities Act  of  1933, or the  Securities
Exchange Act of 1934, whether made before or after the date hereof and irrespective of any general
incorporation language in any such filing.  Information used  on the graph for  the NASDAQ
Pharmaceutical Stocks Total Return Index and the NASDAQ Stock Market Index (U.S.) was prepared
by the Center for Research in Security Prices,  a source believed to be reliable, but  we are  not
responsible for any errors or omissions  in such information.

$450

$400

$350

$300

$250

$200

$150

$100

$50

$0

2010

2011

2012

2013

2014

2015

ImmunoGen Inc.

NASDAQ Stock Market (US Companies)

NASDAQ Pharmaceutical Index

20AUG201509524920

IMMUNOGEN, INC.
NASDAQ STOCK MARKET  INDEX  (U.S.)
NASDAQ PHARMACEUTICAL STOCKS TOTAL

. . . . . . . . . . . . . . . . . . . . . . . . . $100.00 $131.50 $180.58 $178.96 $127.83 $155.12
. . . . . . . . . $100.00 $133.27 $145.10 $170.81 $223.11 $255.90

RETURN INDEX* . . . . . . . . . . . . . . . . . . . . . . . . . $100.00 $129.87 $152.45 $210.78 $299.22 $414.84

2010

2011

2012

2013

2014

2015

*

This index represents a group of peer issuers compiled  by  the  Center  for Research  in Security Prices.

The above graph and table assume $100  invested  on June 30, 2010 with all dividends reinvested, in

each  of our common stock, the NASDAQ  Stock  Market Index  (U.S.) and the NASDAQ
Pharmaceutical Stocks Total Return Index. Upon written request by  any shareholder,  we will promptly
provide a list of the companies comprising the NASDAQ Pharmaceutical  Stocks Total Return Index.

Corporate Information

Directors

Executive Officers

Corporate Headquarters

Chairman of the Board 
Stephen C. McCluski 
Former Senior Vice President and  
Chief Financial Officer, 
Bausch & Lomb, Inc.

Daniel M. Junius 
President and Chief Executive Officer, 
ImmunoGen, Inc.

Mark Goldberg, MD 
Former Executive Vice President, 
Medical and Regulatory Strategy, 
Synageva BioPharma Corp.

Dean J. Mitchell 
Executive Chairman of the Board,  
Covis Pharma Holdings S.a.r.l.

Nicole Onetto, MD, MSc 
Deputy Director and  
Chief Scientific Officer,  
Ontario Institute for Cancer Research

Kristine Peterson 
Chief Executive Officer, Valeritas, Inc.

Howard H. Pien 
Former Chairman and Chief Executive 
Officer, Medarex, Inc.

Joseph J. Villafranca, PhD 
President,  
BioPharmaceutical Consultants, LLC

Richard J. Wallace 
Former Senior Vice President 
Research and Development,  
GlaxoSmithKline plc 

Daniel M. Junius 
President and  
Chief Executive Officer

Richard Gregory, PhD 
Executive Vice President  
and Chief Scientific Officer

David B. Johnston 
Executive Vice President and  
Chief Financial Officer

John M. Lambert, PhD 
Executive Vice President and  
Distinguished Research Fellow

Charles Q. Morris, MBChB, MRCP (UK) 
Executive Vice President and  
Chief Development Officer

Sandra E. Poole 
Executive Vice President,  
Technical Operations

Craig Barrows 
Vice President, General Counsel  
and Secretary

Ellie Harrison 
Vice President and  
Chief Human Resources Officer

Peter J. Williams 
Vice President,  
Business Development

ImmunoGen, Inc. 
830 Winter Street 
Waltham, MA 02451 
781-895-0600 
www.immunogen.com

Annual Meeting

11:00 AM on November 10, 2015 
at the offices of the Company 
830 Winter Street 
Waltham, MA 02451

Stock Transfer Agent 
and Registrar

Broadridge Corporate Issuer  
Solutions, Inc. 
P.O. Box 1342 
Brentwood, NY 11717 
Phone: 855-697-4961 
Fax: 215-553-5402 
Email: shareholder@broadridge.com

Auditors

Ernst & Young LLP 
Boston, MA

Shareholder Inquiries

Information about ImmunoGen can 
be found at www.immunogen.com. 
Inquiries related to the Company may 
be directed to the Investor Relations 
department at our headquarters. 
Communications related to stock and 
transfer requirements, including lost 
stock certificates and change of name 
or address, should be directed to the 
Transfer Agent.

This  annual  report  includes  forward-looking  statements  based  on  management’s  current  expectations.  These  statements  include,  but  are  not  limited  to,  ImmunoGen’s  expectations  related  to  the 
advancement of new Company and partner compounds into clinical testing, the initiation of new clinical trials, the timing of next-step clinical decisions, and the timing and occurrence of the presentation 
of new preclinical and clinical data, of potential business development events, and of potential future regulatory submissions. For these statements, ImmunoGen claims the protection of safe harbor for 
forward-looking statements provided by the Private Securities Litigation Reform Act of 1995. Various factors could cause ImmunoGen’s actual results to differ materially from those discussed or implied 
in the forward-looking statements, and you are cautioned not to place undue reliance on these forward-looking statements, which are current only as of the date of this annual report. Factors that could 
cause future results to differ materially from such expectations include, but are not limited to: the timing and outcome of ImmunoGen’s and the Company’s partners’ research and clinical development 
processes; the difficulties inherent in the development of novel pharmaceuticals, including uncertainties as to the timing, expense and results of preclinical studies, clinical trials and regulatory processes; 
ImmunoGen’s ability to financially support its product programs; ImmunoGen’s dependence on collaborative partners; industry merger and acquisition activity; and other factors more fully described in 
ImmunoGen’s Annual Report on Form 10-K for the fiscal year ended June 30, 2015 and other reports filed with the Securities and Exchange Commission.

Kadcyla®, Herceptin®, and Rituxan® are registered trademarks of their respective owners.

830 WINTER STREET, WALTHAM, MA 02451 

PHONE: 781-895-0600

W W W. I M M U N O G E N .C O M