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ImmunoGen
Annual Report 2013

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FY2013 Annual Report · ImmunoGen
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H I G H   P O T E N T I A L   C O M P O U N D S

Wholly Owned by ImmunoGen 

In Development through Partnerships

We have three wholly owned compounds with our 
Targeted Antibody Payload (TAP) technology in clinical 
testing, with fourth on track to enter the clinic this year. 

IMGN901 – Potential new treatment for small-cell lung 
cancer – an aggressive cancer with a median survival of 
less than a year – and other CD56-positive cancers.

•  Randomized Phase II trial underway.

•  Results, next-step decision expected in 2014.

IMGN853 – Potential new treatment for many ovarian, 
endometrial and non-small cell lung cancers.

•  Encouraging initial data reported.

•  First efficacy data in target patient populations 
  expected in 2014.

IMGN529 – Potential new treatment for non-Hodgkin 
lymphoma (NHL) and other B-cell malignancies.

•  Only agent in development for NHL to contain an active  
  antibody plus the TAP technology used in Kadcyla®.

•  Presentation of first clinical data expected in 2014.

IMGN289 – Potential new treatment for  many 
head and neck and non-small cell lung cancers.

•  EGFR-targeting TAP compound that provides both 
  EGFR  inhibition and direct cancer killing.

•  Investigational New Drug (IND) application active – 
  human clinical testing expected to start by year end.

Kadcyla – Commercialization off to a great start!

•  ImmunoGen now earning growing royalty revenue.

•  Lead Phase III trial, EMILIA, showed survival benefit, 
  plus tolerability advantages, compared to standard care.

•  FDA approved in late February and launched in US 
  soon after by Genentech, a member of the Roche Group.

•  Roche reported US sales of approximately $19 million 
  for 1Q 2013 and $68 million for 2Q 2013.

•  Progress being made outside the US, including 
  regulatory achievements in key international markets.

Roche is developing Kadcyla for multiple uses – for 
advanced and early stage HER2-positive breast cancer,
and for advanced HER2-positive gastric cancer.

Other leading companies – Amgen, Bayer, Biotest, Lilly, 
Novartis, Sanofi – are developing targeted anticancer 
compounds under license with ImmunoGen.

•  Compounds in development for glioblastoma, 
  mesothelioma, multiple myeloma, NHL, ovarian cancer, 
  renal cell carcinoma, and other cancers.

•  Seven compounds are already in the clinic through 
  these collaborations, with submission of INDs for 
  additional TAP compounds expected in 2014.

•  Encouraging initial findings reported for three 
  compounds, with clinical data for most if not all of these  
  seven compounds expected by mid-2014.

Components of an Antibody-Drug Conjugate with ImmunoGen Technology

Antibody –Targeting vehicle; 
may also have anticancer activity

Cancer-cell killing agent – Purpose-developed; 
far more potent than traditional chemotherapies

Linker – Designed to be stable in the bloodstream and to 
control release of the cytotoxic agent once inside the 
cancer cell

Antibody 

Cancer-cell killing agent

Linker

 
Dear Fellow Shareholders, 

ImmunoGen has entered a new stage: in 

February 2013, the first product with our TAP 
technology, Kadcyla®, began commercialization. There 
is now increasing recognition that our wholly owned 
TAP compounds potentially can generate significant 
value for our shareholders. And while Kadcyla and our 
partnership with Roche is the most visible, all of our 
partners are making meaningful progress with their 
product programs.  

Kadcyla – Starting Commercialization 

On February 22, 2013, the US Food and Drug 

Administration (FDA) approved the marketing of 
Kadcyla for the treatment of patients with HER2-
positive metastatic breast cancer who had previously 
received Herceptin® and a taxane.  

This approval means practicing cancer 

physicians across the US can now use Kadcyla to help 
make a difference for their patients. We have heard 
some very powerful patient stories and are proud of 
our role in this achievement.  

The launch of Kadcyla also marks the start of 

ImmunoGen earning royalty income, which we 
recognize one quarter after that of the product sales. 
We are delighted with the initial uptake of Kadcyla in 
the US. We expect sales growth here initially to come 
from increased use for its current indication and, over 
time, from its approval for additional uses.  

Sales growth is also expected to come from the 
launch of Kadcyla in more geographies, again with a roll 
out of additional indications over time. The number of 
countries in which Kadcyla is approved has been 
increasing rapidly, and include Japan, Switzerland, and 
Canada. Also, the key advisory board for the European 
Union has recommended its approval there. We are 
very pleased with the progress being made with Kadcyla 
on a global basis. 

We believe Kadcyla will make an important 
difference for many patients for years to come and, 
because of this, will generate significant revenue to 
ImmunoGen. Kadcyla demonstrates the power  
of our TAP technology to provide meaningful benefits  
for patients with cancer.  

Building and Advancing Our Wholly Owned Pipeline 

As excited as we are about Kadcyla, we believe 
the greatest value for our shareholders will come from 
applying our technology and expertise to establish our 
own pipeline of high potential anticancer compounds.  

we are working to expeditiously advance to clinical 
proof of concept. To help achieve this, late last year we 
brought in a Chief Development Officer – Dr. Charles 
Morris – to oversee all product development-related 
functions, including Clinical and Regulatory, as well as 
to further build out these areas to meet our increasing 
demands. 

The development of novel therapeutics is risky, 

and there is no guarantee that any or all of these four 
compounds will make it to market. We believe each, 
however, has the potential to make a meaningful 
difference to patients with cancer and to generate 
significant value for our shareholders. 

IMGN901 – Potential To Be the First New Type of Drug 
for Newly Diagnosed Small-Cell Lung Cancer in 30 
Years  

We are assessing our IMGN901 TAP compound 

for first-line treatment of extensive disease small-cell 
lung cancer (SCLC) in our NORTH Phase II trial. This is a 
highly challenging cancer, and we believe that if 
IMGN901 can strongly benefit patient outcomes, it will 
be a game-changer for ImmunoGen. 

The treatment regimen for newly diagnosed 

extensive disease SCLC has been substantially the same 
for three decades. Median survival time remains less 
than a year, principally because the median duration of 
benefit from front-line care is under six months and the 
likelihood of responding to any subsequent treatment is 
low. 

The NORTH trial assesses whether adding 

IMGN901 to a front-line standard of care, etoposide 
plus carboplatin, extends the time to disease 
progression. It will also provide initial information on 
the potential impact of IMGN901 on duration of patient 
survival.  

In early 2013, we increased the size of the 
NORTH trial from 120 to 135 evaluable patients as a 
result of modifying the IMGN901 dose. Patient 
enrollment in the study − which has been brisk – should 
be completed by late September 2013.  

We expect to have the data needed to make 

key next-step decisions for IMGN901 by mid-2014. 
Among these is whether we should invest in the 
preparations needed to advance IMGN901 into 
registration testing. Once we have analyzed the data we 
plan to report the topline outcome and decisions. We 
also plan to present the underlying clinical findings at 
an appropriate medical conference.  

We now have four product candidates – 

It would be immensely gratifying to have 

IMGN901, IMGN853, IMGN529, and IMGN289 – that 

IMGN901 make a difference for patients with SCLC.  

IMGN853 – Potential New Drug for Treatment-
Resistant Ovarian Cancer 

This TAP compound is a potential treatment 

for tumors that highly express folate receptor α (FRα), 
which include many cases of ovarian, endometrial, and 
non-small cell lung cancer (NSCLC). We currently expect 
its lead use to be for the treatment of platinum-
resistant ovarian cancer. 

A first step in the clinical testing of a potential 

new anticancer drug is to determine the highest dose 
that can be tolerated by patients. IMGN853 is currently 
in such dose-finding Phase I testing. Impressively, it has 
already demonstrated evidence of activity, as reported 
at the annual meeting of the American Society of 
Clinical Oncology (ASCO) in June. 

Once an appropriate dose of IMGN853 is 

established, we will begin assessing it for the treatment 
of specific types of FRα-positive cancers to gain early 
information on its activity in target patient populations. 
If we see the desired signals of efficacy, we will start the 
process of advancing IMGN853 into registration testing.  

We plan to report new IMGN853 clinical 

findings at a medical meeting in mid-2014. We will 
make the next-step decisions for it when we have the 
appropriate data, which we currently expect to be later 
in 2014.  

IMGN529 – Novel Profile Could Provide Unique 
Benefits for B-Cell Malignancies  

Unlike most ADCs in the clinic, IMGN529 

contains an antibody that, in preclinical testing, 
demonstrates marked anticancer activity even before 
the potent payload agent is attached. Thus, IMGN529 is 
designed to kill target cancer cells through multiple 
mechanisms of action – those of its antibody 
component as well as that of its payload.  

IMGN289 – Novel EGFR-Targeting TAP Compound 

In mid-2013, we submitted the IND for our 

third innovative new anticancer compound in two 
years, IMGN289. This TAP compound is a potential new 
treatment for tumors that highly express EGFR, 
including many cases of squamous cell NSCLC and head 
and neck cancer.  

We sought to create an EGFR-targeting TAP 

compound because of the medical need in EGFR-
positive cancers and because of commonalities 
between EGFR and HER2, the target of Kadcyla. Like 
HER2, EGFR is a member of the ErbB family, is 
overexpressed on solid tumors, plays a role in the 
cancer process, and has been validated by non-ADC 
antibody therapeutics (Erbitux® and Vectibix®). 

To do this, we needed to develop an antibody 
that effectively targets EGFR, but does not prompt the 
level of skin toxicity that occurs with other EGFR-
targeting therapies. We believe our scientists were 
successful based on our preclinical findings. The next 
step is to confirm these findings in clinical testing. 

IMGN289 is on track to enter the clinic this 
year, and we expect to report initial clinical findings 
with it in the latter part of 2014. 

The Seven Other Clinical-Stage Partner Compounds 

Seven other product candidates besides 
Kadcyla are in the clinic through our partnerships. 
Encouraging initial clinical data have been reported for 
three of these, and we expect findings for most, if not 
all, of the compounds to be reported by mid-2014, 
including the first SAR3419 Phase II data.  

Finally, we expect INDs for additional 
compounds to be submitted by ImmunoGen partners  
in 2014. 

This was achieved by our scientists successfully 

In Closing 

creating multiple antibodies to a challenging, and thus 
underutilized, target found on B cells, CD37. They then 
selected the antibody demonstrating the best 
anticancer properties for use in IMGN529. 

IMGN529 is currently in dose-finding Phase I 
testing. The pace of this trial slowed recently because 
we saw some toxicity at lower-than-expected doses. 
We are encouraged by the initial signs of activity seen 
at these low doses. Possible reasons for the toxicity 
have been identified, and we have developed a plan to 
move forward. 

In 2014, we expect to report IMGN529 clinical 

data and to advance it into assessment in specific 
patient populations. 

As you can tell, we believe 2014 will be an 

important year for a number of our programs and also 
those of our partners. We look forward to learning and 
reporting the clinical findings, the decisions and other 
progress with considerable excitement.  

I thank you for your support. 

Sincerely,  

Daniel M. Junius 
President and CEO 
September 20, 2013 

 
 
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, 2013
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, 2012: $1,070,664,433 (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, 2013: 85,109,108 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  12, 2013  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

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

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

Page
Number

3
28
42
42
42
42
43

44
44

45
59
60

102
102
104

105
105

105
105
105

106

107

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, 2013  unless otherwise indicated. For  a
description of the risk factors affecting or  applicable to our business, see  ‘‘Risk  Factors,’’  below.

Overview

We  are a biotechnology company that develops targeted anticancer therapeutics. All  of our  wholly
owned clinical and preclinical product  candidates are antibody-drug conjugates, or  ADCs, which use a
monoclonal antibody to deliver a small molecule to targeted cells.

We  developed our Targeted Antibody Payload, or TAP,  ADC technology to  enable the creation of

highly effective, well-tolerated anticancer products.  A TAP compound consists of an antibody that binds
specifically to an antigen found on the targeted  cancer  cells with one  of our  potent cancer-cell  killing
agents attached using one of our engineered linkers.  The  antibody  component  enables a TAP
compound to target cancer cells expressing its antigen, and the highly potent cell-killing agent  serves to
kill these cells. Our linkers are engineered to keep  the cell-killing agent securely attached to the
antibody  while traveling through the  bloodstream, and then control its release and  activation  once
inside a cancer cell. Depending on the target, the  antibody  component  of the TAP compound  may
serve only as a targeting vehicle or it  may  also have  anticancer  activity.

We  develop our own product candidates using our TAP technology with antibodies from our
research programs. We now have four wholly owned, clinical-stage anticancer compounds—IMGN901,
IMGN853, IMGN289, and IMGN529. We also license to other  companies limited rights to use our
technology with their antibodies to create products. The most advanced compound with our TAP
technology is Kadcyla(cid:4) (ado-trastuzumab emtansine), which was launched  in the U.S.and Switzerland
earlier this year by Genentech, a member  of the Roche Group.  Kadcyla comprises Roche’s trastuzumab
antibody,  which is the active ingredient  of  their Herceptin(cid:4) product, with our DM1 cell-killing agent
attached using our thioether engineered linker. Six  other TAP compounds and one unconjugated, or
‘‘naked,’’ antibody product candidate are in clinical testing through our partnerships.  Our partnership
agreements entitle us to earn royalties  on product sales, if any,  and milestone payments with agreed
upon achievements. 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 and Sanofi. We began receiving royalties on Kadcyla sales in  the fourth
quarter of our 2013 fiscal year.

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,
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
‘‘Investor Information’’ section of our website.

3

Pipeline: Kadcyla and Earlier-Stage Product  Candidates

Listed in the tables below are the compounds in  the clinic through our own  programs and our
collaborations with other companies. Additional earlier-stage compounds are in development by us and
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 all 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(s)

Target

Most Advanced Status

IMGN901 . . . . . . . . . . . . . .
IMGN853 . . . . . . . . . . . . . . Ovarian  cancer, non-small cell

Small-cell lung cancer

CD56
Folate receptor (cid:2)

Phase II
Phase I

lung cancer

IMGN289 . . . . . . . . . . . . . . Head and neck cancer,

IMGN529 . . . . . . . . . . . . . . Non-Hodgkin lymphoma

non-small cell lung cancer

EGFR

CD37

Active IND*

Phase I

Collaborative Partner Compounds**

Compound

Lead Indication(s)

Target

Kadcyla . . . . . . . . . . . . . . . . Previously treated HER2-positive

HER2

metastatic breast cancer

Partner

Roche

Most Advanced
Status

Marketed

Solid tumors

SAR3419 . . . . . . . . . . . . . . . DLBCL, B-ALL***
SAR566658 . . . . . . . . . . . . .
SAR650984 . . . . . . . . . . . . . Multiple myeloma
AMG 172 . . . . . . . . . . . . . . Kidney cancer
AMG 595 . . . . . . . . . . . . . . Glioblastoma
BAY 94-9343 . . . . . . . . . . . . Mesothelioma, ovarian cancer
BT-062 . . . . . . . . . . . . . . . . Multiple myeloma

CD19
CA6
CD38
CD70

Sanofi
Sanofi
Sanofi
Amgen
EGFRvIII Amgen
Bayer
Mesothelin
Biotest
CD138

Phase II
Phase I
Phase I
Phase I
Phase I
Phase I
Phase I

*

IND: Investigational New Drug Application

** All  are ADCs, except for SAR650984,  which is a  ‘‘naked’’ antibody therapeutic

*** DLBCL: diffuse large B-cell lymphoma; B-ALL:  B-cell acute  lymphoblastic leukemia

Kadcyla (previously referred to as T-DM1)

Kadcyla is an ADC that consists of trastuzumab, which is the  active component of Roche’s
antibody  therapeutic, Herceptin (trastuzumab), with our DM1 cell-killing agent attached  using our
thioether engineered linker. Kadcyla is  in  global development by  Roche, under  a license  from us.

Kadcyla was granted marketing approval in February 2013 by  the  U.S.  Food and Drug

Administration, or FDA. It is approved  for the treatment  of HER2-positive  metastatic breast cancer in
patients who previously received Herceptin  and a  taxane. In the EMILIA  Phase III trial, Kadcyla  was
found to significantly improve both overall  survival and progression-free survival compared to standard
of care. These were the co-primary endpoints of  the trial. Kadcyla was also associated  with fewer
Grade 3 or greater adverse events, which are more severe side effects.

Roche also has applied for marketing approval of Kadcyla in the  European Union and  in Japan,

with decisions there expected in late 2013 and in  2014, respectively.

4

Roche is developing Kadcyla for a number of additional indications, including for patients with

(cid:129) Metastatic HER2-positive breast cancer that has  not  previously  been treated—Roche  is assessing
Kadcyla for this use in the Phase III  trial, MARIANNE. Roche  intends to use MARIANNE
results, if favorable, to apply in 2015 for marketing approval  of Kadcyla for this indication,  both
used alone and used with Perjeta(cid:4) (pertuzumab). Roche expects the data from this  trial  in 2014.

(cid:129) Early stage HER2-positive breast cancer—Roche plans  to evaluate Kadcyla in several  early stage

HER2-positive breast cancer settings. In early 2013,  patient  enrollment commenced in  its
KATHERINE Phase III trial, which evaluates  Kadcyla for the treatment of patients with residual
invasive disease following pre-operative  therapy. Roche has  said it plans to initiate  registration
trials evaluating Kadcyla for use in the  adjuvant and  neoadjuvant settings.

(cid:129) Advanced HER2-positive gastric cancer—Roche is evaluating Kadcyla for the  treatment of

patients with this cancer in its GATSBY trial. Roche  intends to use the results from GATSBY,  if
favorable, to apply in 2015 for marketing  approval for this  use.

IMGN901

Our most advanced wholly owned product candidate is IMGN901, or lorvotuzumab mertansine.
We  created IMGN901 for the treatment of CD56-positive cancers,  which include small cell lung cancer,
or SCLC, Merkel cell carcinoma, multiple  myeloma, ovarian cancers, carcinoid tumors, and  other
cancers of neuroendocrine origin. IMGN901 consists of  a CD56-targeting  antibody  with our DM1
cell-killing agent attached using one  of  our hindered disulfide linkers.

In early clinical testing, IMGN901 has been found to be generally  well tolerated and to

demonstrate evidence of activity when used as  a single agent to treat CD56-positive solid  tumors and
multiple myeloma. IMGN901 also has  been found to be generally  well tolerated and to demonstrate
evidence of activity when used in combination with  Revlimid(cid:4) (lenalidomide) and dexamethasone for
treating  CD56-positive multiple myeloma.

In preclinical models of SCLC, use of IMGN901  in combination with etoposide plus carboplatin,
or E/C,  was found to achieve markedly greater anticancer activity than  either IMGN901 or E/C alone.
E/C  is  a standard of care for the treatment of newly diagnosed SCLC. Based on the encouraging
activity seen both preclinically and in  early  clinical testing, we are assessing IMGN901 for the treatment
of patients with newly diagnosed extensive  disease SCLC in  our Phase II  NORTH trial. Patients in the
NORTH trial receive treatment with IMGN901 plus  E/C or  with E/C alone. We  expect to make certain
development-related decisions based on  the results from this trial.

IMGN853

We  created our IMGN853 product candidate to treat cancers  that highly express folate receptor (cid:2),

or FR(cid:2). FR(cid:2)-positive cancers include many cases of ovarian cancer, endometrial cancer and
adenocarcinoma non-small cell lung cancer, or NSCLC. IMGN853 consists of a FR(cid:2)-targeting antibody
with our potent DM4 cell-killing agent attached  using one of our linkers engineered to counteract  one
drug resistance pathway that cancer cells can develop.

IMGN853 is currently in Phase I clinical testing.  Once the maximum  tolerated dose,  or MTD,  has
been established in the dose-finding phase of the trial,  we  plan to evaluate IMGN853 used at  that  dose
in the expansion phase of the trial. There,  IMGN853 will  be  evaluated  specifically in patients with
either FR(cid:2)-positive ovarian cancer, endometrial cancer  or adenocarcinoma NSCLC. The first
IMGN853 clinical data were reported at a medical conference  in June 2013. The compound  was found
to be generally well tolerated and to demonstrate evidence of activity.

5

IMGN289

Our IMGN289 product candidate is a potential new treatment  for cancers that highly  express
EGFR. EGFR-positive cancers include squamous cell carcinoma  of  the head and neck, or SCCHN,  and
types of NSCLC. IMGN289 consists  of  our  EGFR-binding  antibody  with our DM1  cell-killing agent
attached using our thioether linker. In  preclinical testing, the  antibody  component  of IMGN289 was
found to have meaningful anticancer  activity against EGFR-positive cancer cells sensitive  to  EGFR
inhibition. The full product candidate, which  includes DM1,  demonstrates  superior activity  against these
cancers, and also against EFGR-positive  cancers not sensitive  to  EGFR inhibitors. The DM1 enables
IMGN289 to kill EGFR-positive cancer  cells by a second method that  is independent of the sensitivity
of these  cells to EGFR inhibitors.

We  submitted an IND for IMGN289 to the FDA in late June 2013; it became active in late July

2013. We are preparing to begin Phase  I testing of the  compound.

IMGN529

Our IMGN529 TAP compound targets CD37,  which is expressed on B-cell malignancies  such as
non-Hodgkin lymphoma, or NHL, and on chronic  lymphocytic leukemia. ImmunoGen scientists  have
found the expression profile of CD37 on  NHL subtypes to be similar to that of CD20, the  target of
Rituxan(cid:4).

IMGN529 comprises an antibody that, in  preclinical testing, has demonstrated  meaningful
anticancer activity, our DM1 cell-killing agent,  and our thioether  engineered linker. We believe
IMGN529 is a highly differentiated product candidate  for B-cell  malignancies because it  combines the
anticancer activity of its antibody component with the  actions of one of our  potent cell-killing agents.
IMGN529 is in Phase I clinical testing  for  the treatment of NHL.

Compounds in Development by Our Partners

In addition to Kadcyla, seven other compounds  are in clinical testing through our collaborations

with other companies. Additionally, several of our  collaborative  partners have TAP  compounds in
earlier stages of development.

Sanofi

Each  of the three clinical-stage Sanofi compounds—SAR3419,  SAR566658  and SAR650984—was

created as part of a broader research collaboration between ImmunoGen and Sanofi.  The  antibodies in
all three compounds were developed by  ImmunoGen scientists.  The  two TAP  compounds, SAR3419
and SAR566658, contain our DM4 cell-killing agent attached with one of our hindered disulfide linkers.
Sanofi has additional compounds created under that  agreement in earlier  stages of development.

SAR3419 targets CD19 and is a potential treatment for  CD19-expressing B-cell malignancies.

Sanofi is evaluating SAR3419 in Phase II  clinical testing for  both a type of NHL called diffuse  large
B-cell lymphoma, or DLBCL, and in B-cell acute lymphoblastic leukemia, or  B-ALL. In Phase  I
clinical testing, SAR3419 showed encouraging  efficacy  and tolerability in  the treatment of  NHL
previously treated with approved anticancer agents.

SAR566658 is a TAP compound in development as a potential treatment for  CA6-expressing solid

tumors, including ovarian cancers. Sanofi  is evaluating SAR566658 in Phase  I  clinical testing.

SAR650984 is a CD38-targeting therapeutic,  or ‘‘naked’’, antibody created by ImmunoGen for the

treatment of hematological malignancies.  It is  in Phase  I  clinical  testing for the treatment  of blood
cancers including multiple myeloma.

6

Amgen

Pursuant to the terms of a separate right-to-test agreement entered into in 2000,  Amgen took
licenses in 2009 for rights to use our  TAP technology  to  develop  therapeutics targeting CD70 and
EGFRvIII and has since advanced product candidates AMG 172 and AMG 595 into clinical testing.  In
late 2012 and in early 2013, Amgen took  licenses  under the same right-to-test  agreement for  rights to
use our TAP technology to develop therapeutics to two additional targets,  which are undisclosed.
Amgen has no remaining rights under the  right-to-test agreement to take licenses  to  additional targets.

AMG 172 is a potential treatment for CD70-expressing cancers,  and is in Phase I clinical  testing
for the treatment of patients with clear cell renal cell carcinoma. AMG 595 is a  potential  treatment for
EGFRvIII-expressing cancers. It is in Phase  I clinical testing for the treatment  of patients with
glioblastoma.

Bayer

BAY 94-9343 was created by Bayer under a single-target  license agreement  that  granted Bayer

rights to use our technology to develop  TAP compounds  to  the target, mesothelin, and is  currently  in
Phase I clinical testing.

The first clinical data for BAY 94-9343 were reported at a scientific conference in early 2013.
These data were from the dose-escalation  part of  its Phase I trial and showed that the  compound was
generally well tolerated and demonstrated  evidence of activity among patients  with mesothelin-
expressing solid tumors treated at higher dose  levels. The compound is now being evaluated in the
expansion phase of the trial specifically  in  patients  with mesothelioma and in  patients  with ovarian
cancer. It has been granted orphan drug  status for the treatment of mesothelioma.

Biotest

BT-062 was created by Biotest under a  single-target license  agreement that granted Biotest rights
to use our TAP technology with antibodies that target CD138, an antigen found on multiple  myeloma
and certain solid tumors. We have opt-in  rights  with respect to BT-062 in the U.S.

Encouraging Phase I clinical data have been reported with BT-062 used as  a single agent to treat
patients with multiple myeloma. Biotest  is assessing  BT-062 used as part of  a combination regimen for
this  cancer. In preclinical testing, BT-062 demonstrated activity against several types of aggressive solid
tumors. It is expected to advance into clinical testing  for  the treatment of  one  or more types  of  solid
tumors.

Lilly  and Novartis

Our most recent partnerships are with Lilly and Novartis. Compounds are in preclinical

development under these agreements.

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 2013  approximately  1.7 million new
cases of cancer will be diagnosed in the  U.S.  and  that approximately 580,000 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.

7

Below is information about incidence  of cancers  we are  seeking to treat with  our  wholly owned
compounds. For the approved product,  Kadcyla, information  about the  incidence of HER2-positive
breast cancer is available from Roche,  the marketer  of  the product.

IMGN901—The lead indication for IMGN901is  for the  treatment of extensive disease SCLC.
Based on our own studies and scientific literature, we  believe that CD56 is  expressed  on almost  all
cases of SCLC. Based on ACS estimates and other sources, we believe that at  least  22,800 new  cases of
SCLC will be diagnosed in the U.S. in  2013. SCLC tends to spread  broadly  through the body quite
early in the course of the disease, and—according to the  ACS—approximately  two-thirds  of patients
with SCLC have extensive disease at the  time of diagnosis.

IMGN853—Our IMGN853 compound is  a potential treatment  for  many cases of epithelial ovarian

cancer, endometrial cancer and adenocarcinoma  NSCLC.  Based on published sources, we  believe
approximately 22,000 new cases of ovarian cancer will be diagnosed in the  US in 2013 and epithelial
ovarian cancer accounts for approximately  85% to 90% of  these  ovarian cancer cases.  We believe that
approximately 49,600 cases of endometrial cancers will be diagnosed in  the US  in 2013. Additionally,
based on published sources, we believe  that approximately 194,000 new cases  of  NSCLC  will be
diagnosed in the US in 2013, and that  approximately  40% of these  cases are  the adenocarcinoma
subtype.

IMGN289—Our IMGN289 compound is  a potential treatment  for  many cases of head  and neck
cancer and types of NSCLC. The ACS  estimates  that  approximately  53,600 new  cases of head and neck
cancers will be diagnosed in 2013. Research conducted  at ImmunoGen  found that over 90%  of these
types of cancer strongly express EGFR. Based on  ACS estimates,  we  believe approximately 194,000 new
cases of NSCLC will be diagnosed in the  U.S. in  2013. This figure comprises three main subtypes—
adenocarcinoma, squamous cell carcinoma, and large cell carcinoma. These subtypes account  for
approximately 40%, 25-30%, and 10-15% of NSCLC  diagnoses, respectively. Research with tumor
samples conducted at ImmunoGen found that  approximately 20% of adenocarcinoma cases  and about
half of squamous and of large cell carcinoma  cases strongly express EGFR.

IMGN529—We are assessing our IMGN529 compound  for  the  treatment of NHL. Based on ACS

estimates, we believe approximately 69,700  new cases  of  NHL will be diagnosed  in the U.S. in 2013.

Out-licenses and Collaborations

We  selectively out-license restricted access to our TAP  technology to other companies to provide

us with cash to fund our own product  programs and to expand the utilization of  our technology. These
agreements typically provide the licensee with rights to use  our TAP  technology with  antibodies 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 supplied 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 and product approval. 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 regulatory submissions and a positive
regulatory decision. Currently, we have  a license  with Roche relating to Kadcyla that provides  us with
royalty revenue and may provide us with  significant milestone payments  in the foreseeable future.

8

Below is a table setting forth our active  agreements, the number  of  targets licensed  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(4)

Lilly(4)

Right-to-test

Right-to-test

2000

2000

2003

2006

2006

2008

2010

2011

US Marketing
Approval

Phase I

Phase II

Research/Preclinical

Phase I

Phase  I

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 and
Switzerland and Roche has submitted a marketing application for the compound in the EU  and
Japan. The remaining four licenses were entered into between  2005 and  2008, and the
development status of product candidates under  each of those licenses  is research/preclinical.

(3) Amgen has three exclusive, single-target licenses  and one  non-exclusive, single-target license.

(4)

Sanofi,  Novartis and Lilly each have the right to take  a defined number of exclusive, single-target
options that provide the right to take  single-target licenses,  on pre-negotiated terms, to specified
targets during the respective option periods. As of June 30, 2013,  Novartis has  taken one license to
two related targets, one on an exclusive  basis and one on  a non-exclusive basis.  In  August 2013,
Lilly took an exclusive license to a single target.

Roche

In May 2000, we granted Roche, through its Genentech unit,  an exclusive development and
commercialization license to our maytansinoid TAP technology  for use with antibodies  or other
proteins that target HER2, such as trastuzumab.  In February 2013,  the US  FDA  granted marketing
approval to the anti-HER2 TAP compound,  Kadcyla. 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.

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 determined based on  annual calendar  year net  sales  in each

9

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;

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

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

(cid:129) 5% of net sales above $700 million.

The sales in the country count towards  the annual sales in that  territory for purposes  of calculation  of
sales tiers.

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:

(cid:129) Genentech makes certain third party  license  payments in  order to exploit the  TAP 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; or

(cid:129) a third party obtains regulatory approval in a country to market and sell a product  containing a

conjugate of an anti-HER2 antibody with a maytansinoid, in which  case royalties will be reduced
to a flat 1% of net sales of Kadcyla in such country during  the royalty term  as long as such
competing product has not been withdrawn from  the market 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 the adjustments described in  either of the above two circumstances.

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.

The US marketing approval of Kadcyla in February 2013 triggered a $10.5 million  milestone

payment to us. Through June 30, 2013,  we have received and recognized a total of $24.0  million  in
milestone payments under this agreement.  The  next potential milestone  we will be entitled  to  receive
will be either a $5 million regulatory milestone  for marketing approval of Kadcyla  in Europe or a
$5 million regulatory milestone for marketing approval  of  Kadcyla in  Japan,  depending  on which  occurs
first.

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

TAP 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, 2013. 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

In September 2000, we entered into a  ten-year right-to-test agreement  with Abgenix, Inc.  which

was later acquired by Amgen. The agreement provided Amgen with the right  to  (a) test our
maytansinoid TAP technology with Amgen’s antibodies under a right-to-test, or research, license,

10

(b) take options, with certain restrictions,  to  individual targets  selected  by Amgen on either an exclusive
or non-exclusive basis for specified option periods and (c) upon exercise of those  options,  take
exclusive or non-exclusive licenses to  use our maytansinoid TAP technology to develop and
commercialize products directed to the  specified targets on previously agreed-upon terms. Amgen no
longer has the right to take additional  options  under the  right-to-test agreement and  there are no
unexercised options outstanding.

Under the right-to-test agreement, in September 2009, November 2009 and December  2012,

Amgen took three exclusive development and commercialization licenses, for  which we  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 we received an exercise fee of $500,000. We  are
entitled to receive up to a total of $34  million in milestone payments  for each exclusive license and up
to a total of $17 million in milestone  payments for the non-exclusive license, plus  in each case, royalties
on the commercial sales of any resulting  products.

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

the exclusive 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 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 milestone we will be entitled to receive under the December 2012 development  and
commercialization license will be a development milestone  for  IND  approval which will  result in  a
$1 million payment being due to us.  The  next potential milestone  we  will be entitled to receive under
the May 2013 development and commercialization  license  will be a development milestone  for IND
approval which will result in a $500,000 payment  being  due to us.

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 TAP technology in the  creation of products directed  to  these  targets. The product
candidates (targets) currently in development under the collaboration  include SAR3419 (CD19),
SAR650984 (CD38), SAR566658 (DS6, also known as CA6) and  two  earlier-stage compounds that have
yet to be disclosed. For each of the targets  included in  the collaboration at this  time, we are entitled to
receive up to a total of $21.5 million  in milestone payments,  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

11

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 our company.

Through June 30, 2013, we have received  and recognized a total of  $16.5 million in milestone
payments related to compounds covered  under  this  agreement now and in the  past, including  a total of
$8 million in milestone payments related  to two product candidates previously in the collaboration  that
have been returned to us along with  the  rights to the respective targets.

The next potential milestone we will be entitled to receive  with respect to SAR3419 will be for
initiation of a Phase III clinical trial,  which  will result in  a $3 million payment  being  due.  The next
potential milestone we will be entitled to receive with respect to each  of SAR566658 and  for
SAR650984 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 we will be entitled to receive  for each  of the unidentified targets 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 separate right-to-test  agreement with Sanofi. The agreement
provides Sanofi with the right to (a)  test  our maytansinoid TAP technology  with Sanofi’s antibodies to
targets that were not included in the  collaboration  agreement described above under  a right-to-test, or
research, license, (b) take exclusive options, with  certain restrictions, to individual targets selected by
Sanofi for specified time periods and  (c) upon  exercise  of those options, take exclusive licenses to use
our  maytansinoid TAP 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 2011for its final three-year term by payment of a $2 million extension fee. No additional
extensions are included in this agreement.

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.

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. No development  and commercialization license  has yet  been taken
under the right-to-test agreement.

Biotest

In July 2006, we granted Biotest an exclusive  development and  commercialization license to our
maytansinoid TAP technology for use  with antibodies that target CD138.  The product candidate BT-062
is in development under this agreement.  We received a $1  million  upfront payment  from Biotest  upon

12

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.

The agreement also provides 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. 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 costs of product development
and commercialization in the U.S. along  with the  profit, if any, from product sales in 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.

Through June 30, 2013, we have received  and recognized a total of  $500,000 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 Phase IIb clinical trial (as defined in  the agreement) which will
result in a $2 million payment being due.

Bayer HealthCare

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

license to our maytansinoid TAP technology for use  with antibodies or other proteins  that  target
mesothelin. The product candidate BAY 94-9343 is currently  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, 2013, 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.

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Novartis

In October 2010, we entered into a right-to-test agreement with Novartis. The agreement  provides

Novartis with a right to (a) test our TAP technology with Novartis’ antibodies directed to individual
targets selected by Novartis under a right-to-test, or research, license, (b) take  exclusive  options,  with
certain restrictions, to individual targets selected by Novartis for specified option  periods, and (c) upon
exercise of those options take exclusive licenses to use our  TAP technology  to  develop  and
commercialize products for a specified number of individual targets on terms agreed upon at  the
inception of the right-to-test agreement.  The initial term  of the right-to-test agreement is three years,
which  may be extended by Novartis for up to two additional one-year periods by the payment of
additional consideration. Novartis must exercise its options for the development and commercialization
licenses by the end of the term of the right-to-test agreement,  after which  any then  outstanding options
will lapse.

We  received a $45 million upfront payment in  connection with the execution of the  right-to-test
agreement, and we are also entitled to receive additional payments under the  agreement for  research
and development activities performed on behalf of Novartis during the term  of  the agreement. For
each  development and commercialization license taken, we are entitled to  receive an exercise fee of
$1 million and up to a total of $199.5  million in milestone payments,  plus royalties on the commercial
sales of any resulting products.

Effective March 29, 2013, we and Novartis amended the right-to-test agreement  so that Novartis

can take a license  to develop and commercialize products directed at two pre-defined and related
undisclosed 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  be  converted  to  an exclusive
target by notice and payment to us of an  agreed upon fee  of at least $5 million, depending on specific
circumstances. 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, on March 29,  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. We received a  $1  million upfront fee with the  execution  of this  license.
Additionally, the execution of this license provides  us  the opportunity  to receive milestone payments
totaling $199.5 million or $238 million,  depending on the composition of  any resulting  products. The
first potential milestone we will be entitled to receive will  be a $5.0 million development  milestone for
commencement of a Phase I clinical  trial.

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

In December 2011, we entered into a three-year right-to-test  agreement with  Lilly. The agreement
provides Lilly with the right to (a) take exclusive options, with  certain restrictions,  to  individual targets
selected  by Lilly for specified option periods,  (b)  test our maytansinoid TAP  technology with  Lilly’s
antibodies directed to the optioned targets under  a right-to-test, or research, license, and  (c)  upon
exercise of those options take exclusive licenses to use our  maytansinoid  TAP technology  to  develop

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and commercialize products for a specified number  of individual targets on terms  agreed upon at the
inception of the right-to-test agreement.  Lilly must exercise its options for  the development and
commercialization licenses by the end  of  the term of  the right-to-test agreement, after which any  then
outstanding options will lapse. Under  the terms  of the agreement,  Lilly took an exclusive development
and commercialization license to a single target in August 2013.

We  received a $20 million upfront payment in  connection with the execution of the  agreement, and
we are also entitled to receive additional payments  under the agreement for  research  and development
activities performed under the agreement on behalf of  Lilly during the term of the research license. For
the first development and commercialization  license taken, which occurred in  August 2013, we are
entitled to receive up to a total of $200.5  million in milestone payments, plus tiered royalties in  the
mid-single to low-double digits on the  commercial sales of any resulting products.  For each subsequent
development and commercialization license taken, we  are entitled to receive an exercise fee of
$2 million and up to a total of $199  million in milestone payments,  plus royalties on the commercial
sales of any resulting products.

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.

In-Licenses

From time to time we may in-license  certain rights to targets or technologies for use  in conjunction

with our internal efforts to develop TAP compounds  and  related technologies. These  licenses include
rights to certain antibodies. In exchange, we may be obligated to pay upfront  fees,  potential  milestone
payments and royalties on any product  sales.

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, 2013, our  patent portfolio had a total  of  459 issued
patents worldwide and 477 pending patent applications worldwide that we own or license from third
parties. We seek to protect our TAP 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, maytansinoid and other cell-killing agents, and complete antibody-drug
conjugates, or immunoconjugates, 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 maytansinoid technology  to  be  a key component of our overall corporate  strategy.
We  currently own 42 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

15

cell-killing agent and antibody-maytansinoid conjugates  incorporating DM4 that are expected to remain
in force until 2024-2025.

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

conjugation methods, immunoconjugate formulations and the use of specific  antibodies  and
immunoconjugates 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 2021-2029,
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 immunoconjugates from their constituent antibody, linker and cell-killing agent moieties.
These issued patents will expire in 2021-2027,  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 a TAP compound or may be developed as  a therapeutic, or  ‘‘naked,’’
antibody  anticancer compound. Among  these  patents is an issued U.S. patent claiming a method of
humanizing murine antibodies to avoid  their detection by the human immune system.  We have received
patents in other jurisdictions, including Europe and Japan, that correspond to our antibody
humanization U.S. patent. These patents will expire between  2013 and  2014.

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. For example,  we also  own issued patents covering proprietary
derivatives of non-maytansinoid cell-killing molecules. However, we  do not currently consider  these
additional patent families to be material  to our business.

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  have in-licensed intellectual property relating to our IMGN901 product  candidate from
Dana-Farber Cancer Institute. We do  not  believe that the terms  of this  license  are material to our
business or prospects.

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.

In addition, 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

16

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,
Rocheand 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.  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
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.

17

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  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
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 studies due to safety
concerns or non-compliance.

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 progress
reports detailing the results of the clinical  trials must be submitted at least annually. In addition, 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

18

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 studies 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  studies are
intended to establish the overall risk-benefit ratio of the  product candidate  and provide,  if
appropriate, an adequate basis for product  labeling.

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. 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
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

19

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.

U.S. Review and Approval Processes

The results of product development, preclinical studies and clinical trials, along  with descriptions of

the manufacturing process, analytical tests conducted on the chemistry of the  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 post-marketing
clinical trials. Priority review and accelerated approval do  not  change the standards  for approval,  but
may expedite the approval process.

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

20

commercial value of the product. In addition, the  FDA may require  us 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 recently enacted 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
studies for most drugs and biologicals, 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 studies  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 studies are complete or  that additional safety or effectiveness data needs
to be collected before the pediatric studies begin. After April  2013, 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.

Market exclusivity provisions under the FDCA  also can delay the submission or the approval  of

certain applications. The FDCA provides  a five-year period of non-patent marketing exclusivity  within
the U.S.  to the first applicant to gain  approval  of  an NDA for a new chemical entity. A drug is a  new
chemical entity if the FDA has not previously approved any other  new drug  containing the same  active
moiety, which is the molecule or ion responsible for the action of the drug substance. During the
exclusivity period,  the FDA may not accept  for  review an abbreviated  new  drug  application,  or ANDA,
or a 505(b)(2) NDA submitted by another company for another version  of  such drug where the
applicant does not own or have a legal right  of  reference to all the data  required  for approval.
However, an application may be submitted after four years  if it contains a certification of  patent
invalidity or non-infringement. The FDCA also  provides three years of  marketing  exclusivity for  an
NDA,  505(b)(2) NDA or supplement to an  existing NDA if new clinical  investigations, other than
bioavailability studies, that were conducted or sponsored by the applicant, are deemed  by  FDA to be
essential to the approval of the application,  for example, for new indications, dosages, or strengths  of
an existing drug. This three-year exclusivity covers only the conditions associated with the  new clinical

21

investigations and does not prohibit the FDA from approving ANDAs  for drugs containing  the original
active  agent. Five-year and three-year exclusivity will not delay the submission or  approval of a full
NDA; however, an applicant submitting  a full NDA would be required  to  conduct or  obtain  a right of
reference to all of the preclinical studies  and  adequate and  well-controlled  clinical trials  necessary  to
demonstrate safety and effectiveness.

Pediatric exclusivity is another 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 studies in neonates, the FDA  is required to include its rationale  for  not  requesting those
studies.  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
studies.  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  studies 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  studies 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.

Between February 2012 and March 2013, the FDA issued several draft  guidance documents  on

biosimilar product development. The draft guidance documents are: ‘‘Scientific Considerations in
Demonstrating Biosimilarity to a Reference  Product,’’ ‘‘Quality Considerations  in Demonstrating
Biosimilarity to a Reference Protein Product,’’  ‘‘Biosimilars: Questions and Answers  Regarding
Implementation of the Biologics Price  Competition and Innovation Act  of 2009,’’ and ‘‘Formal
Meetings Between the FDA and Biosimilar Biological Product Sponsors or Applicants.’’ 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 received public comments on the draft

22

documents and intends to issue final guidance  documents in the  future. Nevertheless,  the absence  of a
final guidance document does not prevent a sponsor from seeking licensure of a  biosimilar under the
BPCIA.

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 granted Orphan Drug designation to our lorvotuzumab mertansine  compound when

used for the treatment of Merkel cell  carcinoma  (MCC),  small-cell lung cancer (SCLC) and multiple
myeloma (MM). Orphan drug designation provides ImmunoGen with  seven  years  of  market  exclusivity
that begins once lorvotuzumab mertansine receives FDA marketing approval for the use for  which the
orphan drug status was granted. Also, through a separate process,  lorvotuzumab mertansine has  been
granted orphan medicinal product designation for the treatment of MCC,  SCLC and MM in the
European Union. Orphan medicinal  product designation provides  ImmunoGen  with ten years of
market exclusivity that begins once lorvotuzumab mertansine receives  European  approval for the use
for which it was granted. We may pursue these designations for other  indications for  lorvotuzumab
mertansine, and 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

23

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
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 draft guidance  in June 2013, 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 about 20 new
drugs.

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,  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  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

24

on the market. Drugs may be promoted only for  the approved indications and in accordance  with the
provisions of the approved label.

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,

25

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
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 some 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 of  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 the
research will be developed by the Department  of  Health and Human  Services, the Agency for
Healthcare Research and Quality and  the  National  Institutes for  Health, and periodic reports on the
status of the research and related expenditures will be made to Congress. Although the results of the
comparative effectiveness studies are not intended to mandate coverage policies for public or private
payors, it is not clear what effect, if any, the  research will  have on the sales of 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, is expected to have a significant impact on  the health care industry. ACA is expected  to
expand coverage for the uninsured while  at the  same time  containing 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

26

working to repeal ACA. These challenges  add to the uncertainty of the  changes enacted as  part of
ACA.

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 by
significantly lower.

Research and Development Spending

During  each of the three years ended  June 30, 2013,  2012 and  2011, we spent approximately

$87.1 million, $69.2 million and $63.5  million, respectively,  on research  and development activities.

Raw Materials and Manufacturing

We  procure certain raw material components of finished conjugate,  including antibodies,  DM1,
DM4, 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, Cytovance Biologics LLC, SAFC, Inc. 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, 2013, we had 280 full-time employees,  of  whom 239 were  engaged  in research and

development activities. Of the 239 research and development employees, 113 research and development
employees hold post-graduate degrees,  of which 51 hold  Ph.D. degrees and five 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, Kadcyla and Perjeta are registered trademarks of Genentech. Revlimid is a  registered

trademark of Celgene Corporation. Rituxan is  a registered trademark of Biogen Idec  Inc.

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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, 2013,  we had an

accumulated deficit of $576.8 million.  For the years ended June 30, 2013, 2012, and 2011, we generated
losses of $72.8 million, $73.3 million  and $58.3  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  significant
resources supporting our existing collaborators  as they  work  to  develop, test and commercialize TAP
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. Only one of our collaborators’ product  candidates
has generated commercial revenue and  our only revenues to  date have been primarily from  upfront and
milestone payments, research and development support and  clinical materials reimbursement from our
collaborative partners. 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
2015. 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

28

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

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

TAP product candidate has obtained marketing approval. Our TAP  product candidates and/or our
collaborators’ TAP product candidates  may not prove to be safe, effective  or commercially  viable
treatments for cancer and our TAP 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 TAP  technology. One of
these products was later taken off the market by its  owner  due to toxicity  concerns. If  our  TAP
technology fails to generate product candidates that are  safe, effective and commercially  viable
treatments for cancer, or 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.

29

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

30

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,

31

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 TAP  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.

32

Our royalty revenues will likely fluctuate  and  may  become  more  difficult to  forecast in future periods.

On February 22, 2013, the FDA granted marketing approval to Kadcyla. Kadcyla was developed by
Roche, through its Genentech unit, under a license we  granted in May 2000,  pursuant  to  which we are
entitled to receive milestone payments plus royalties  on commercial sales of Kadcyla. Roche and  its
affiliates have also applied for marketing approval of Kadcyla  in Europe and Japan. As a  result of the
start of commercialization of Kadcyla in  the U.S. and the possible  marketing approvals elsewhere, we
expect an increasing proportion of our  revenue and operating results  to  derive from  royalties based  on
the commercial sales of Kadcyla. 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. Kadcyla is currently the only product
with respect to which we are entitled  to  receive royalties  that  has received marketing approval.

The Roche agreement provides for separate  tiered royalty  structures with respect to sales in  two
territories: 1) the U.S. and 2) the rest  of the world. The royalty rate Roche  must  pay on sales in  each
of these  two territories increases on  incremental sales in  a given calendar year in  the applicable
territory above certain net sales thresholds. As a  result of the  tiered  royalty structure,  Roche’s  average
royalty rate should increase over the course  of  a calendar year as more  Kadcyla is  sold in that year.
However, we recognize royalty revenues  in the quarter  in which  they are received,  which are  based on
Kadcyla sales in the preceding quarter.  Accordingly, we anticipate that the average royalty rate for
payments we receive from Roche will  generally increase  between the second quarter of one  calendar
year (our fourth fiscal quarter) and the  first calendar quarter  of  the next (our  third  quarter  of  the next
fiscal year).

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
expense 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
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

33

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  TAP

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 most of our collaborative  partners for  preclinical studies  and early-stage clinical
testing. Two of our partners have contracted  for separate, large-scale manufacturing capacity to make
materials to support potential future commercialization of their TAP 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
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.

34

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 TAP 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 complicated  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
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

35

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

(cid:129) their degree 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 for product  candidates, both ours and our collaborative

partners.

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 drug 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

36

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 and
Bristol-Myers Squibb. 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 acquisition 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.

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

37

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. While  we cannot  predict what  form  any  new patent reform  regulations
ultimately may take, final governmental  rule-making  and  case law interpreting  the new  statute could
introduce new substantive rules, procedures and case law bases for challenging patents, and certain
reforms  that make it easier for competitors to challenge  our patents could  have a material adverse
effect on our business and prospects.

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

38

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
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

39

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
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, 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 TAP technology, new  collaborations and clinical advancement  or discontinuation of
product  candidates that make use of  our TAP  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 collaborations. 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

40

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

July 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 decrease.

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.

41

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 89,000 square  feet of laboratory and office  space in a  building located at

830 Winter Street, Waltham, MA. The  initial term of the  830 Winter Street lease expires on March 31,
2020, with an option for us to extend the lease  for  two additional five-year terms.  In  December 2009,
we entered into a  sublease, as sublessor,  to rent 14,100 square  feet  of our original office and laboratory
space at 830 Winter Street, Waltham, MA through January  2015. Due to space requirements,  in April
2012, we entered into a sublease agreement for  the rental  of 7,310 square feet  of additional laboratory
and office space at 830 Winter Street, Waltham, MA  for an  initial term of three years with  a
conditional option to extend through October 2017. 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.

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.

42

Daniel M. Junius, age 61, joined ImmunoGen in  2005, and has served as  our  President and  Chief
Executive Officer since 2009. Prior to that  he served as  our President and  Chief  Operating Officer  and
Acting Chief Financial Officer from  July  2008 to December 2008, as  our  Executive Vice President and
Chief Financial Officer from 2006 to July 2008, and  as our Senior  Vice President and  Chief  Financial
Officer from 2005 to 2006. Mr. Junius  has also served as a director of ImmunoGen since 2008.
Mr. Junius holds a Masters of Management  from Northwestern  University’s Kellogg School of
Management.

John M. Lambert,  Ph.D., age 62, joined ImmunoGen in  1987, and has served as  our Executive
Vice President and Chief Scientific Officer since July 2008. Prior to that he served in  various capacities
of increasing responsibility in the areas of  research  and  development. Dr. Lambert holds a  Ph.D. 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.

Charles Q. Morris, MB, ChB, MRCP (UK),  age  48, 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, and as Vice President, Clinical  Research,  Oncology, at Cephalon from 2007 to 2008.
Dr. Morris holds two Bachelor of Medicine degrees from  Sheffield University Medical School and is a
member of the Royal College of Physicians  of  London.

James J. O’Leary,  MD, age 49, joined  ImmunoGen in 2008,  and  has served as our Vice  President
and Chief Medical Officer since that date. Prior to joining ImmunoGen, Dr. O’Leary served as Senior
Medical Director Clinical Oncology of Bayer Corporation, a  pharmaceutical company,  from 2006 to
2008. Dr. O’Leary has a Doctor of Medicine degree from the State University of New  York—Health
Science Center at Brooklyn.

Gregory D. Perry, age 53, joined ImmunoGen in 2009,  and has served as our Executive  Vice
President and Chief Financial Officer  since April 2011. Prior to that, he served as  our Senior  Vice
President and Chief Financial Officer  from 2009  to  April 2011. Prior to joining  ImmunoGen, he  served
as Chief Financial Officer of Elixir Pharmaceuticals, Inc., a pharmaceutical  company, from 2007  to
2008. Mr. Perry is also a director of Advanced Cell  Technology, Inc. Mr. Perry has notified us of  his
intention to resign from ImmunoGen, effective September 13, 2013.

Craig Barrows, age 58, joined ImmunoGen  in 2007, and has  served as our Vice  President,  General

Counsel and Secretary since that date.

Peter J. Williams, age 59, joined ImmunoGen  in August 2009,  and has  served  as our Vice

President, Business Development since that date.  Prior to joining ImmunoGen, he served as a  Senior
Director of Business Development at Alnylam Pharmaceuticals, Inc., a biopharmaceutical company,
from 2006 to August 2009.

Theresa  G. Wingrove, Ph.D., age 55, joined ImmunoGen  in January 2011, and  has served as our

Vice President, Regulatory Affairs since that date. Prior to joining ImmunoGen,  she  served  as Vice
President, Regulatory and Clinical Affairs, at  Histogenics, Inc., a medical device company,  from 2006 to
January 2011. Dr. Wingrove holds a Ph.D. in  biochemical toxicology from  the University  of Rochester
School of Medicine and Dentistry, and completed her postdoctoral work at the University of Rochester
Medical Center.

Item 4. Mine Safety Disclosures

None.

43

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 2013

Fiscal Year 2012

High

Low

High

Low

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

$18.10
$15.77
$16.54
$18.83

$12.51
$10.85
$12.92
$13.91

$15.55
$14.44
$14.61
$16.74

$ 9.42
$10.09
$11.38
$12.22

As of August 20, 2013, the closing price per share of our common stock  was  $16.16, as reported  by

NASDAQ, and we had approximately 658 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.

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, 2013. The  information set  forth
below should be read in conjunction  with ‘‘Management’s Discussion and Analysis of Financial
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,

2013

2012

2011

2010

2009

Consolidated Statement of Operations  Data:
Total revenues . . . . . . . . . . . . . . . . . . . . . . . .
Total operating expenses . . . . . . . . . . . . . . . . .
Other income (expense), net . . . . . . . . . . . . . .
(Benefit) provision for income taxes . . . . . . . .

$ 35,535
108,544
198
—

$ 16,357
89,614
(62)
—

$ 19,305
79,493
1,914
—

$ 13,943
65,178
58
(265)

$ 27,988
59,804
(221)
(100)

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

$ (72,811) $ (73,319) $ (58,274) $ (50,912) $ (31,937)

Basic and diluted net loss per common  share . .

$

(0.87) $

(0.95) $

(0.85) $

(0.87) $

(0.63)

Basic and diluted weighted average common

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

84,063

76,814

68,919

58,845

51,068

Consolidated Balance Sheet Data:
Cash, cash equivalents and marketable

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

$194,960
213,596
121,847

$160,938
180,308
83,890

$191,206
217,641
139,969

$110,298
137,208
102,048

$ 71,125
100,704
66,857

44

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 (ADC’s) 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  Targeted Antibody
Payload, or TAP, technology consists  of  a  monoclonal antibody that binds specifically to an antigen
target found on cancer cells with multiple  copies of one  of our  proprietary  cell-killing  agents attached
to the antibody using one of our engineered linkers. Its  antibody  component  enables a TAP 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 TAP compounds, the  antibody component also has
anticancer activity of its own. Our TAP  technology  is designed to enable the creation of highly
effective, well-tolerated anticancer product candidates. All  of the TAP 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  use our expertise in
antibodies and cancer biology to develop  ‘‘naked,’’ or non-conjugated, antibody anticancer  product
candidates.

We  have used our proprietary TAP technology in conjunction  with our in-house antibody expertise

to develop our own anticancer product  candidates.  We have also  entered into agreements that enable
companies to use our TAP 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 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 and Sanofi.  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, 2013,  we had
approximately $195 million in cash and cash equivalents compared  to  $160.9 million as of June 30,
2012.

We  anticipate that future cash expenditures will  be  partially offset by collaboration-derived

proceeds, including milestone payments,  royalties  and upfront  fees.  Accordingly, period-to-period
operational results 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 and/or clinical projects.  However, we cannot provide  assurance that any such opportunities

45

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, 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 TAP
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  if  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, 2013, we had the following two types of agreements with the  parties identified below:

(cid:129) Development and commercialization licenses  to  use our TAP technology and/or certain other

intellectual property to develop compounds to a specified target antigen (referred to as
development and commercialization licenses, as distinguished from  our right-to-test agreements
described elsewhere):

Amgen (three exclusive single-target  licenses;  one non-exclusive single-target license)

Bayer HealthCare (one exclusive single-target  license)

Biotest (one exclusive single-target license)

Novartis (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 (exclusive license to multiple individual targets)

46

(cid:129) Option/research agreement for a defined period of time  to  secure development and

commercialization licenses to use our  TAP  technology to develop anticancer  compounds to
specified targets on established terms (referred to herein as right-to-test agreements):

Sanofi

Novartis

Lilly

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 TAP 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.  Royalty rates may vary over
the royalty term depending on our intellectual property rights. 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 TAP  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 TAP technology,  our
pricing practices and pricing objectives, the  likelihood that technological improvements will be made,
the likelihood that technological improvements 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

47

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, 2013, 2012 and 2011, 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
$755,000, $85,000, and $1.3 million, 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  clinical

48

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 its licensees’ net sales of  covered products.  Generally,  under  these agreements we are 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. We recognize royalty revenues  when it can reliably estimate such amounts and  collectability is
reasonably assured. As such, we generally recognizes  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 TAP technology  for a

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

49

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 TAP 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 TAP 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.

50

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 2013,
2012 and 2011, 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  $798,000, $748,000 and $1.7  million,  respectively, of charges  to  research and development
expense related to raw material inventory identified as excess. We also  recorded $38,000 to write down
certain raw material inventory to its net  realizable value,  which is also included in research and
development expense for the year ended June 30, 2012.  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, 2013, 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, 2013, 2012  and 2011  was $12.4 million,
$9.9 million and $5.5 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, 2013 were $35.5  million compared with

$16.4 million and $19.3 million for the  years ended June 30,  2012 and 2011, respectively. The
$19.1 million increase in revenues in fiscal year 2013  from fiscal year 2012 is attributable to all revenue
categories, as discussed below. The $2.9  million decrease in revenues in fiscal  year 2012 from fiscal year
2011 is attributable to lower revenues from research and development  support and  clinical materials
revenue, partially offset by higher revenues from  license and milestone fees.

51

Revenue from license and milestone  fees  for  the year  ended June 30, 2013  increased  approximately

$15 million to $24.2 million from $9.2 million  in the year ended  June 30, 2012. Revenue from license
and milestone fees for the year ended  June 30,  2011 was $6.4 million. 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. Included  in license  and milestone fees for
the year ended June 30, 2012 was a $3  million  milestone payment related to the initiation  of Phase II
clinical testing of SAR3419 achieved  under  our collaboration agreement with Sanofi and two $1 million
milestone payments related to regulatory  milestones  achieved under our license agreements with
Amgen. Also during the year ended June 30,  2012, Biogen Idec terminated its exclusive license  to  our
TAP technology to develop and commercialize therapeutic compounds to the target Cripto and  as a
result, we recognized the remaining $270,000 of the  $1 million upfront fee received from Biogen Idec
upon execution of the license which had  been  previously  deferred. Also,  during fiscal 2012, we made a
change in the estimate of our period  of  substantial involvement  as it  relates to our exclusive license
with Bayer HealthCare which resulted in an  increase to license  and milestone fees of $1.2  million for
the fiscal year ending June 30, 2012 compared  to  amounts that would have  been recognized pursuant to
our  previous estimate. Included in license  and  milestone fees for the year ended  June 30, 2011 were a
$1.0 million milestone payment related to the  initiation of Phase I clinical  testing of SAR566658 by
Sanofi and a $2.0 million milestone payment  related to the  IND  filing  of  BAY  94-9343  by  Bayer
HealthCare. 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,  2013, 2012 and 2011 is
included in the following table (in thousands):

License and Milestone Fees

Collaborative Partner:

Year Ended June 30,

2013

2012

2011

Amgen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Bayer HealthCare . . . . . . . . . . . . . . . . . . . . . . . . . . .
Biogen Idec . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Biotest . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Novartis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Roche . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Sanofi . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Other . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

$

883
521
—
25
11,131
10,500
1,167
—

$3,118
1,839
270
120
—
—
3,795
19

$1,123
2,615
28
130
—
—
2,435
62

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

$24,227

$9,161

$6,393

Deferred revenue of $64.9 million at June 30, 2013  represents payments  received from  our
collaborators pursuant to our license agreements, including  a $20  million upfront payment received
from Lilly during fiscal 2012 and $38.4  million remaining of a  $45 million upfront payment  received
from Novartis during fiscal 2011, which  we have  yet to earn pursuant to our revenue  recognition policy.

Research and development support revenue was $7.9 million for the year ended  June 30, 2013,
$4.5 million for the year ended June 30,  2012, and $7.3 million for  the year  ended June 30, 2011.  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

52

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, 2013, 2012 and  2011 is included in  the
following table (in thousands):

Research and Development Support

Collaborative Partner:

Year Ended June 30,

2013

2012

2011

Amgen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Bayer HealthCare . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Biotest . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Lilly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Novartis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Sanofi
Other . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

$ 417
30
921
806
5,605
22
72

$1,011
27
627
250
2,588
14
—

$3,971
452
896
—
1,338
144
455

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

$7,873

$4,517

$7,256

Clinical materials revenue increased  by approximately $164,000  to  $2.8 million  in the year ended
June 30, 2013 compared to $2.7 million in the  year  ended June  30, 2012. We earned clinical materials
revenue of $5.7 million during the year ended June 30,  2011. During the years ended  June  30, 2013,
2012 and 2011, 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. The  increase
in clinical materials revenue in fiscal  year  2013 as compared to fiscal year  2012 is primarily due to
greater DMx shipments to certain collaborators in  support of development and manufacturing efforts.
The decrease in clinical materials revenue in  fiscal year 2012 as  compared to fiscal year 2011 is
primarily related to less clinical material shipped in  support of one of our collaborator’s trials  due  to
larger scale material requirements being provided by another vendor, as well as less preclinical
materials shipped during the year. 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, 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.

In February 2013, the US FDA granted marketing approval to Kadcyla,  a  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, $592,000 of  royalties  on  net sales  of Kadcyla for the
period ended March 31, 2013 was recorded in  our  fourth quarter  of fiscal 2013. No royalty revenue was
recorded  in fiscal years 2012 and 2013. We expect royalty  revenue to increase  in future  periods  as the
underlying net sales of Kadcyla increase.

53

Research and Development Expenses

Our net  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 TAP  technology;

(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 antibody for  our internal product candidates,  including fill/

finish  services;

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

activities;

(cid:129) non-pivotal and pivotal development activities with contract manufacturers for 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, 2013 increased $17.9  million  to
$87.1 million from $69.2 million for the  year ended June 30, 2012.  Research and  development expense
was $63.5 million for the year ended June 30,  2011. Research and development salaries and related
expenses increased by $6.2 million to $39.3  million  in the year ended June 30,  2013 compared  to  the
year ended June 30, 2012 and increased by $5.4 million in  the year  ended June 30, 2012 compared to
the year ended June 30, 2011. The average number of our research personnel increased to 226 for the
year ended June 30, 2013 compared to 207 for the year ended  June  30, 2012. We had  an average of
192 for the year ended June 30, 2011.  Included in  salaries and related expenses for the year ended
June 30, 2013 is $7.3 million of stock compensation costs compared  to  $5.3 million  and $3.3 million  of
stock compensation costs for fiscal years 2012 and  2011, respectively. The higher stock  compensation
costs in fiscal years 2013 and 2012 are  driven by higher stock prices and increases in the number of
annual options granted due to increases  in personnel. Clinical trial  costs  increased $3.2 million to
$8.9 million during fiscal year 2013 compared to fiscal year 2012 and increased $845,000  in fiscal year
2012 compared to fiscal year 2011 due primarily to new  trials initiated, including  a Phase II trial for
IMGN901 in small-cell lung cancer, increased site management costs driven from expanded sites and
higher  patient enrollment. Additionally,  antibody  development and supply expense  increased
$5.9 million to $10.8 million during fiscal year 2013  compared to fiscal  year 2012  and increased
$1.2 million in fiscal year 2012 compared  to fiscal year 2011 due  to  the advancement of our internal
programs and timing of supply requirements.

54

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,

2013

2012

2011

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

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

$16,827
21,143
7,203
24,019

$15,208
16,884
7,238
24,123

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

$87,073

$69,192

$63,453

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 increased $679,000 to $17.5  million in fiscal year 2013
from fiscal year 2012 and $1.6 million to $16.8  million  in fiscal year 2012 from  fiscal year  2011. The
increase in fiscal years 2013 and 2012  was principally due to an increase in salaries and related
expenses.

55

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 $6.7 million  to  $27.8 million in  fiscal  year 2013 from fiscal  year 2012 and
$4.2 million to $21.1 million in fiscal  year 2012 from fiscal year 2011. The increase in  fiscal year  2013
was primarily the result of an increase in clinical trial costs  due primarily to site  expansion and higher
patient enrollment for the IMGN901 007 Phase  II study for small-cell lung cancer and increased  costs
incurred for the IMGN853 Phase I trial for ovarian cancer which was initiated during the second  half
of fiscal 2012 and began enrolling patients  in fiscal 2013,  as well  as an increase  in salaries and related
expenses. The increase in fiscal year 2012  was principally due to increases in salaries  and related
expenses and increases in clinical trial  costs.  The  increase in  clinical  trial  costs for fiscal 2012 was
primarily the result of advancing two new wholly owned product candidates, IMGN529 and  IMGN853,
into clinical testing during the year. The increase was partially  offset by lower costs incurred  related to
our  IMGN901 and IMGN388 clinical  programs due to completion of earlier-stage IMGN901 clinical
trials and our returning the rights to IMGN388 to its  originator.

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 $574,000 to $7.8 million in fiscal year  2013 from fiscal year 2012  and
expenses decreased $35,000 to $7.2 million  in fiscal year 2012  from  fiscal year 2011. The increase in
fiscal year 2013 was primarily the result of an increase in salaries and related expenses. The decrease in
fiscal year 2012 was primarily due to  a decrease  in contract service expense  due  to  transferring
responsibility for certain outsourced costs to manufacturing operations, partially offset  by  an increase in
salaries and related expenses.

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 $10 million to $34  million  in fiscal year 2013 from fiscal year 2012 and decreased
$104,000 to $24.0 million in fiscal year 2012 from  fiscal  year 2011. The increase  in fiscal year 2013 was
primarily the result of (i) an increase  in antibody development  and supply expense driven by our
IMGN901, IMGN853, IMGN529 and  IMGN289 programs; (ii)  a decrease in  costs capitalized into
inventory due to a lower number of manufactured  batches  of  conjugated  materials on behalf of our
collaborators; and (iii) an increase in salaries and related  expenses. The decrease in fiscal year 2012
was primarily the result of (i) a decrease  in cost of clinical materials revenue due to decreased  orders
of such clinical materials from our partners  and  lower amounts of DMx written off as excess;  (ii) a
decrease in raw materials and disposables  used in  production  due to timing  and mix of  manufacturing
requirements; and (iii) a decrease in  quality-related consultant fees due to internal resources being
added to perform this work. Partially offsetting these decreases,  (i) costs capitalized into inventory due
to a lower number of manufactured  batches of conjugated materials on behalf of our collaborators
decreased; (ii) antibody development and supply expense increased, driven primarily  by  IMGN853  and
IMGN289; and (iii) contract service expense increased due  to  increased fill/finish costs  for IMGN901
and IMGN853, greater linker development  costs and increased release  and stability testing  of  our
internal antibodies.

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

as our ongoing trials, was $10.8 million  in fiscal year 2013, $4.9 million  in fiscal year 2012, and

56

$3.7 million in fiscal year 2011. 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 due  to  our  continuing
advancement of our internal product  candidates through clinical trials,  as well as  expected increases in
salaries and related expenses.

General and Administrative Expenses

General and administrative expenses  for the  year ended June 30, 2013  increased $1.1 million  to
$21.5 million from $20.4 million for the  year ended June 30, 2012.  General and administrative expenses
for the year ended June 30, 2011 were  $16.0 million.  The increase in  fiscal year  2013 was primarily due
to an increase in salaries and related  expenses, particularly stock compensation costs.  The  increase in
fiscal year 2012 was primarily due to  an increase in salaries and related expenses, particularly stock
compensation costs, an increase in patent  expenses and an increase in professional service fees,
including increased accounting, legal and public  reporting fees. We  expect general and administrative
expenses to increase in fiscal 2014 compared to fiscal 2013 due  primarily  to  increases in salaries and
related expenses, particularly stock compensation  expense, and  patent expenses.

Investment Income, net

Investment income for the years ended June 30, 2013,  2012 and 2011 was $126,000,  $66,000 and

$218,000, respectively.

Other Income (Expense), net

Other income (expense), net for the  years ended June 30,  2013, 2012 and 2011  was  $72,000,
$(128,000) and $1.7 million, respectively.  Net realized gains on investments were  $341,000 for  the year
ended June 30, 2011. There were no  gains or losses recognized during the  years  ended June 30, 2013
and 2012. During the years ended June  30,  2013, 2012 and 2011, we recorded  net gains (losses) on
foreign currency forward contracts of $197,000, $(173,000) and $189,000,  respectively. We incurred
$(153,000), $17,000, and $(57,000) in  foreign currency exchange (losses) and gains  related to obligations
with non-U.S. dollar-based suppliers during the  years  ended June  30, 2013, 2012 and  2011, respectively.
In addition, during fiscal year 2011, we  recognized  $1.2 million  of  federal  grant funding awarded under
the Patient Protection and Affordable Care Act of 2010  to  develop new anticancer  therapies.

Liquidity and Capital Resources

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

$194,960
181,511
121,847

$160,938
150,016
83,890

Year Ended June 30,

2013

2012

2011

As of June 30,

2013

2012

(In thousands)

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

57

(In thousands)
$(60,299) $(34,288) $ (7,989)
(660)
90,699

(3,696)
98,017

(2,968)
6,988

Cash Flows

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 and research funding. As  of  June  30, 2013, we had approximately  $195.0 million
in cash and cash equivalents. Net cash  used for operations was $60.3  million, $34.3  million  and
$8.0 million during the years ended June 30, 2013, 2012  and  2011, respectively. The  principal  use of
cash in operating activities for all periods  presented  was  to  fund our  net loss.  Cash  used  in operations
in fiscal 2012 benefited from the $20 million upfront payment  received from Lilly in January 2012 with
the execution of a right-to-test agreement  between the companies and  cash used in  operations  in fiscal
2011 benefited from the $45 million  upfront  payment received from Novartis  in October  2010 with  the
execution of a right-to-test agreement between  the companies.

Net cash used for investing activities  was $3.7  million,  $3.0 million and $660,000 for the years
ended June 30, 2013, 2012 and 2011,  respectively,  and  substantially  represents cash  outflows  from
capital expenditures, partially offset in  fiscal  2011 by cash inflows from the sales and maturities of
marketable securities. Capital expenditures  were $3.8  million,  $2.9 million and  $2.0 million for  the fiscal
years ended June 30, 2013, 2012 and  2011, respectively. Capital expenditures for  the years ended
June 30, 2013, 2012 and 2011 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  $98.0 million,  $7.0 million and  $90.7 million for  the
years ended June 30, 2013, 2012 and  2011, respectively, which includes  the proceeds  from the exercise
of 666,000, 1.4 million and 550,000 stock  options,  respectively. Also,  pursuant to public offerings,  in
fiscal 2013, we issued and sold 6,250,000  shares  of our common stock resulting  in net proceeds of
$94.0 million, and in fiscal 2011, we issued and sold 7,800,000 shares of our common stock  resulting in
net proceeds of $88.0 million.

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 2015. 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, 2013 (in thousands):

Payments Due by Period

Total

Less than
One Year

1-3
Years

4-5
Years

More than
5 Years

Waltham lease obligations(1) . . . . . . . . . . .
Other operating lease obligations . . . . . . .

$37,976
5,473

$5,594
1,042

$11,154
2,175

$11,228
2,227

$10,000
29

Total

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

$43,449

$6,636

$13,329

$13,455

$10,029

(1) Lease agreements were signed in July 2007  and April 2012.  In December 2009, we entered

into a sublease for 14,100 square feet  of our office and laboratory space  at  830 Winter Street,
Waltham, MA through January 2015. We will  receive approximately  $1.1 million in  minimum
rental payments over the remaining term of the sublease,  which is not  included in  the table
above.

58

In addition to the above table, we are  contractually obligated to make 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, 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.

During  fiscal 2013, our development  and commercialization  license with Janssen Biotech was
terminated and, accordingly, we are no  longer obligated to make $41.0 million of potential  future
success-based milestone and third-party  payments under such agreement.  As of June 30,  2013 the
maximum amount that may be payable in the  future under our  current  collaborative agreements is
approximately $2.0 million, $1.4 million of which  is reimbursable by  a third party under a separate
agreement.

Recent  Accounting Pronouncements

In July 2013, the FASB issued guidance  to  address the  diversity in practice  related to the financial

statement presentation of unrecognized tax  benefits as  either a reduction of a deferred tax  asset or a
liability when a net operating loss carryforward, a similar  tax loss, or a tax  credit carryforward exists.
This guidance is effective prospectively for fiscal years, and interim  periods within those  years,
beginning after December 15, 2013. 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 own derivative financial instruments in our investment  portfolio. Accordingly, we  do 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 forward contracts and a Euro-denominated bank
account to manage the foreign currency  exposures that  exist as  part  of  our ongoing business operations.
The contracts are denominated in Euros and  have maturities  of less than one  year. 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 include  a short
duration foreign currency forward contract and a Euro-denominated bank account.  The  contract
provides that we receive certain foreign currencies and  pay U.S. dollars at specified exchange rates at a
specified future date. Although we are  exposed  to  credit and market risk in the  event of future
nonperformance by a counterparty, management  has no  reason to believe that such an  event will  occur.

59

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,  2013 and 2012 . . . . . . . . . . . . . . . . . . . . . . . . . . .
Consolidated Statements of Operations  and  Comprehensive  Loss for the Years Ended  June  30,
2013, 2012, and 2011 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Consolidated Statements of Shareholders’ Equity for the Years Ended  June 30, 2013, 2012,

and 2011 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Consolidated Statements of Cash Flows  for  the Years  Ended June 30,  2013, 2012, and 2011 . . .
Notes to Consolidated Financial Statements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Page

61

62

63

64
65
66

60

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,

2013 and 2012, 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, 2013. Our
audits also included the financial statement schedule  listed  in the Index at  Item 15. These financial
statements and schedule are the responsibility of the  Company’s management.  Our responsibility  is to
express an opinion on these financial statements and schedule  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,  2013 and  2012, and the
consolidated results of its operations and  its cash  flows  for  each  of the three years in the period ended
June 30, 2013, in conformity with U.S. generally accepted accounting principles.  Also, in our  opinion,
the related financial statement schedule, when considered  in relation to the basic financial statements
taken as a whole, presents fairly in all material  respects the information set forth  therein.

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, 2013, based on criteria established  in Internal Control—Integrated Framework  issued by the
Committee of Sponsoring Organizations  of  the Treadway Commission and our report dated  August 29,
2013 expressed an unqualified opinion thereon.

/s/ ERNST & YOUNG LLP

Boston, Massachusetts
August 29, 2013

61

IMMUNOGEN, INC.

CONSOLIDATED BALANCE SHEETS

In thousands, except per share amounts

ASSETS
Cash and cash equivalents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Accounts receivable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Unbilled revenue . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Inventory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Restricted cash . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Prepaid and other current assets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Total current assets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Property and equipment, net of accumulated depreciation . . . . . . . . . . . . . . . .
Long-term restricted cash . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Other assets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

June 30,
2013

June 30,
2012

$ 194,960
—
2,121
703
319
2,581

200,684
10,783
1,912
217

$ 160,938
129
1,196
1,288
319
2,400

166,270
11,633
2,231
174

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

$ 213,596

$ 180,308

LIABILITIES AND SHAREHOLDERS’ EQUITY
Accounts payable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Accrued compensation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Other accrued liabilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Current portion of deferred lease incentive . . . . . . . . . . . . . . . . . . . . . . . . . . .
Current portion of deferred revenue . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

$

Total current liabilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Deferred lease incentive, net of current  portion . . . . . . . . . . . . . . . . . . . . . . .
Deferred revenue, 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

4,498
6,153
6,049
979
1,494

19,173
5,626
63,384
3,566

91,749

$

3,395
4,942
4,589
979
2,349

16,254
6,605
69,761
3,798

96,418

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

—

—

Common stock, $.01 par value; authorized 150,000 shares; issued and
outstanding 84,725 and 77,759 shares  as of June  30, 2013 and 2012,
respectively . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Additional paid-in capital
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Accumulated deficit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

847
697,767
(576,767)

778
587,068
(503,956)

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

121,847

83,890

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

$ 213,596

$ 180,308

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

62

CONSOLIDATED STATEMENTS OF  OPERATIONS AND COMPREHENSIVE LOSS

In thousands, except per share amounts

IMMUNOGEN, INC.

Year Ended June 30,

2013

2012

2011

Revenues:

License and milestone fees . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Research and development support . . . . . . . . . . . . . . . . . . . . . . . .
Clinical materials revenue . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Royalty revenue . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

$ 24,227
7,873
2,843
592

$ 9,161
4,517
2,679
—

$ 6,393
7,256
5,656
—

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

35,535

16,357

19,305

Operating Expenses:

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

87,073
21,471

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

108,544

69,192
20,422

89,614

63,453
16,040

79,493

Loss from operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Investment income, net
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Other income (expense), net . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

(73,009)
126
72

(73,257)
66
(128)

(60,188)
218
1,696

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

$ (72,811) $(73,319) $(58,274)

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

$

(0.87) $

(0.95) $

(0.85)

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

84,063

76,814

68,919

Other Comprehensive Loss . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

—

—

(282)

Total Comprehensive Loss . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

$ (72,811) $(73,319) $(58,556)

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

63

CONSOLIDATED STATEMENTS OF SHAREHOLDERS’ EQUITY

IMMUNOGEN, INC.

In thousands

Common Stock

Shares Amount

Additional
Paid-In
Capital

Accumulated
Other
Accumulated Comprehensive Shareholders’
Income (Loss)

Deficit

Equity

Total

Balance at June 30, 2010 . . . . . . . . . . . . . . . .
Unrealized gains on marketable securities . . . . .
Net loss
. . . . . . . . . . . . . . . . . . . . . . . . . .
Stock options exercised . . . . . . . . . . . . . . . . .
Stock-based compensation expense . . . . . . . . .
Issuance  of common stock in a public offering,

67,931
—
—
550
—

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

7,800
—

$679
—
—
6
—

78
—

$473,450
—
—
2,713
5,452

87,902
326

$(372,363)
—
(58,274)
—
—

—
—

$ 282
(282)
—
—
—

—
—

$102,048
(282)
(58,274)
2,719
5,452

87,980
326

Balance at June 30, 2011 . . . . . . . . . . . . . . . .

76,281

$763

$569,843

$(430,637)

$ —

$139,969

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

—
1,432
—
46
—

—
14
—
1
—

—
6,974
9,938
(1)
314

(73,319)
—
—
—
—

—
—
—
—
—

(73,319)
6,988
9,938
—
314

Balance at June 30, 2012 . . . . . . . . . . . . . . . .

77,759

$778

$587,068

$(503,956)

$ —

$ 83,890

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

—
666
50
—

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

6,250
—

—
6
—
—

63
—

—
4,020
—
12,400

93,928
351

(72,811)
—
—
—

—
—

—
—
—
—

—
—

(72,811)
4,026
—
12,400

93,991
351

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

84,725

$847

$697,767

$(576,767)

$ —

$121,847

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

64

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:
Depreciation and amortization . . . . . . . . . . . . . . . . . . . . . . . . . . .
(Gain) Loss on sale/disposal of fixed assets . . . . . . . . . . . . . . . . . .
Gain on sale of marketable securities . . . . . . . . . . . . . . . . . . . . . .
(Gain) Loss on forward contracts . . . . . . . . . . . . . . . . . . . . . . . . .
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 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Year Ended June 30,

2013

2012

2011

$ (72,811) $ (73,319) $ (58,274)

4,641
(21)
—
(197)
12,751
(109)

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

4,633
51
—
173
10,252
(109)

4,539
292
(808)
253
1,018
(16)
182
219
133
18,219

4,937
9
(341)
(189)
5,778
(4)

(2,873)
107
762
(1,038)
574
38
149
522
(375)
42,229

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

(60,299)

(34,288)

(7,989)

Cash flows from investing activities:

Proceeds from maturities or sales of  marketable securities . . . . .
Purchases of property and equipment, net . . . . . . . . . . . . . . . . .
Proceeds (payments) from settlement of forward  contracts . . . . .

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

Cash flows from financing activities:

Proceeds from stock options exercised . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . .
Proceeds from common stock issuance,  net

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

—
(3,770)
74

(3,696)

4,026
93,991

98,017

—
(2,908)
(60)

(2,968)

6,988
—

6,988

1,201
(2,029)
168

(660)

2,719
87,980

90,699

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

34,022
160,938

(30,268)
191,206

82,050
109,156

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

$194,960

$160,938

$191,206

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

65

IMMUNOGEN, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS

AS OF JUNE 30, 2013

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
$72.8 million during the fiscal year ended  June  30, 2013, and has  an accumulated deficit of
approximately $576.8 million as of June  30,  2013. 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, 2013, the Company had $195.0 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., and  ImmunoGen Europe Limited. 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, 2013 up

through the date the Company issued  these financial  statements. In  August  2013, as part of its right-to-
test agreement, Eli Lilly and Company  took  an exclusive development and commercialization license to
a single target. The Company did not have any other material recognizable or unrecognizable
subsequent events.

66

IMMUNOGEN, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

AS OF JUNE 30, 2013

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 Targeted Antibody Payload, or  TAP, 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  if  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, 2013, the Company had the following two types of  agreements with the  parties

identified below:

(cid:129) Development and commercialization licenses  to  use the  Company’s TAP technology  and/or

certain other intellectual property to develop compounds to a specified target antigen (referred
to as development and commercialization  licenses, as  distinguished from the Company’s
right-to-test agreements described elsewhere):

Amgen (three exclusive single-target  licenses;  one non-exclusive single-target license)

Bayer HealthCare (one exclusive single-target  license)

Biotest (one exclusive single-target license)

Novartis (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 (exclusive license to multiple individual targets)

(cid:129) Option/research agreement for a defined period of time  to  secure development and

commercialization licenses to use the Company’s TAP technology  to  develop anticancer
compounds to specified targets on established terms (referred  to  herein as right-to-test
agreements):

Sanofi

Novartis

Lilly

67

IMMUNOGEN, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

AS OF JUNE 30, 2013

B. Summary of Significant Accounting Policies (Continued)

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 TAP 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.  Royalty rates may vary over
the royalty term depending on the Company’s intellectual property rights. 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 TAP  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 TAP  technology, the Company’s pricing  practices and
pricing objectives, the likelihood that  technological  improvements will be made, the likelihood that
technological improvements 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

68

IMMUNOGEN, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

AS OF JUNE 30, 2013

B. Summary of Significant Accounting Policies (Continued)

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.

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, 2013, 2012  and 2011,  the
difference between the Company’s full cost to manufacture preclinical and  clinical materials on behalf

69

IMMUNOGEN, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

AS OF JUNE 30, 2013

B. Summary of Significant Accounting Policies (Continued)

of its collaborators as compared to total amounts received from collaborators for the manufacture of
preclinical and clinical materials was $755,000, $85,000  and  $1.3 million,  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
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

70

IMMUNOGEN, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

AS OF JUNE 30, 2013

B. Summary of Significant Accounting Policies (Continued)

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

TAP 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.

For right-to-test agreements where the options to secure development and commercialization
licenses to the Company’s TAP 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

71

IMMUNOGEN, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

AS OF JUNE 30, 2013

B. Summary of Significant Accounting Policies (Continued)

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 TAP 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.

Inventory at June 30, 2013 and 2012  is summarized below (in thousands):

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

$ 75
628

$ 129
1,159

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

$703

$1,288

June 30,

2013

2012

Raw materials inventory consists entirely of DM1 and  DM4, proprietary cell-killing agents  the

Company developed as part of its TAP  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

72

IMMUNOGEN, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

AS OF JUNE 30, 2013

B. Summary of Significant Accounting Policies (Continued)

of the collaborators and subject to the  terms and  conditions of respective  supply agreements. As such,
no reserve for work in process inventory is  required.

Raw materials inventory cost is stated  net of write-downs of $810,000  and  $1.3 million as of

June 30, 2013 and June 30, 2012, 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.

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.

73

IMMUNOGEN, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

AS OF JUNE 30, 2013

B. Summary of Significant Accounting Policies (Continued)

During  fiscal years 2013, 2012 and 2011,  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 $798,000,  $748,000 and $1.7  million
respectively, of charges to research and  development expense  related to raw  material  inventory
identified as excess. The Company also recorded $38,000 as  research  and development expense to write
down certain raw material inventory  to its net realizable value in  fiscal  year  2012. No similar charges
were recorded during fiscal years 2013 and 2011.  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, 2013 and 2012  represents research

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

Restricted Cash

Restricted cash at June 30, 2013 and  2012 are cash  balances  securing  irrevocable letters of credit

required for security deposits for the Company’s leased facilities.

Other Accrued Liabilities

Other accrued liabilities consisted of  the following at June  30, 2013 and 2012  (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,

2013

2012

$2,406
1,849
678
411
179
526

$1,773
865
677
351
208
715

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

$6,049

$4,589

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

74

IMMUNOGEN, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

AS OF JUNE 30, 2013

B. Summary of Significant Accounting Policies (Continued)

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, 2013.
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.

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 (losses) on  forward
contracts for the years ended June 30,  2013, 2012 and  2011 were $197,000, $(173,000) and  $189,000,
respectively, and are included in the accompanying  Consolidated  Statement of Operations  as other
income (expense), net. As of June 30, 2013, the  Company had an outstanding  forward contract with a
notional amount equivalent to approximately $57,000 (A41,000), maturing on October 7, 2013. As of
June 30, 2012, the  Company had outstanding forward contracts  with notional amounts  equivalent to
approximately $3.3 million (A2.5 million). The Company does not anticipate using derivative
instruments for any purpose other than hedging  exchange  rate exposure.

75

IMMUNOGEN, INC.

NOTES TO CONSOLIDATED FINANCIAL  STATEMENTS (Continued)

AS OF JUNE 30, 2013

B. Summary of Significant Accounting Policies (Continued)

Cash Equivalents

All highly liquid financial instruments with  maturities of three months or less when  purchased are

considered cash equivalents. As of June  30, 2013 and 2012, cash equivalents consisted  of money market
funds  with underlying investments primarily being U.S.  Government-issued  securities and high quality,
short-term commercial paper.

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. Certain provisions of  ASC Topic 820 related  to  other non-financial  assets and liabilities
were adopted by the Company on July 1,  2009  and did not have  a  material impact on  its financial
position or results of operations upon adoption; however, this standard may impact the Company in
subsequent periods and require additional  disclosures.

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.

As of June 30, 2013, 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, 2013 (in thousands):

Fair Value Measurements at June 30, 2013 Using

Quoted Prices in
Active Markets for
Identical Assets

Significant Other
Observable Inputs

Significant
Unobservable
Inputs

(Level 1)

$197,191

$197,191

(Level 2)

(Level 3)

$—

$—

$—

$—

Cash, cash equivalents and restricted cash .

$197,191

Total

$197,191

76

IMMUNOGEN, INC.

NOTES TO CONSOLIDATED FINANCIAL  STATEMENTS (Continued)

AS OF JUNE 30, 2013

B. Summary of Significant Accounting Policies (Continued)

As of June 30, 2012, 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, 2012 (in thousands):

Cash, cash equivalents and restricted cash .

$163,488

Total

$163,488

Fair Value Measurements at June 30, 2012 Using

Quoted Prices in
Active Markets for
Identical Assets

Significant Other
Observable Inputs

Significant
Unobservable
Inputs

(Level 1)

$163,488

$163,488

(Level 2)

(Level 3)

$—

$—

$—

$—

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

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 $21,000,
$(51,000) and $(9,000) of gains (losses)  on the sale/disposal of certain furniture and equipment  during
the years ended June 30, 2013, 2012,  and  2011, respectively.

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.

77

IMMUNOGEN, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

AS OF JUNE 30, 2013

B. Summary of Significant Accounting Policies (Continued)

Computation of Net Loss Per Common Share

Basic and diluted net loss per common share is calculated  based upon  the weighted average
number of common shares outstanding during the period. 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,

2013

2012

2011

Options outstanding to purchase common stock and unvested
restricted stock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Common stock equivalents under treasury stock method . . . .

7,703
2,149

6,442
2,194

6,491
1,901

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, 2013, 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 13, 2012,
an amendment to  the 2006 Plan was approved and an  additional 3,500,000  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  12,000,000 shares of  the Company’s
common stock, as well as any shares of common stock that are represented by awards granted under
the previous stock option plan, the ImmunoGen,  Inc. Restated Stock Option Plan,  or the Former Plan,
that are forfeited, expire or are cancelled without delivery of shares of common  stock; provided,
however, that no more than 5,900,000 shares shall be added  to  the  2006 Plan from the Former Plan,
pursuant to this provision. 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

78

IMMUNOGEN, INC.

NOTES TO CONSOLIDATED FINANCIAL  STATEMENTS (Continued)

AS OF JUNE 30, 2013

B. Summary of Significant Accounting Policies (Continued)

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,

2013

2012

2011

Dividend . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Volatility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Risk-free interest rate . . . . . . . . . . . . . . . . . . . . . . .
Expected life (years) . . . . . . . . . . . . . . . . . . . . . . .

None
None
None
60.44% 59.70% 58.81%
2.43%
2.16%
0.87%
7.2
7.1
6.3

Using the Black-Scholes option-pricing model, the weighted average grant  date fair  values  of
options granted during fiscal 2013, 2012 and 2011  were $8.60, $9.00, and $5.51 per share, respectively.

A summary of option activity under the 2006 Plan as of June 30, 2013, 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, 2012 . . . . . . . . .
Granted . . . . . . . . . . . . . . . . . . . . . . . .
Exercised . . . . . . . . . . . . . . . . . . . . . . .
Forfeited/Canceled . . . . . . . . . . . . . . . . .

6,442
2,047
(666)
(170)

Outstanding at June 30, 2013 . . . . . . . . .

7,653

Outstanding at June 30, 2013—vested or

unvested and expected to vest . . . . . . .

Exercisable at June 30, 2013 . . . . . . . . . .

7,466

4,202

$ 8.98
$15.22
$ 6.05
$13.87

$10.79

$10.70

$ 7.97

6.89

$44,351

6.84

5.53

$43,991

$36,220

In November 2012, the Company granted an officer of the  Company 50,000 shares of restricted
stock upon hire. Pursuant to the agreement,  the shares vest ratably in quarterly  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,  2013, and
changes during the twelve month period  then ended  is presented  below (in thousands,  except weighted-
average data):

Unvested at June 30, 2012 . . . . . . . . . . . . . . . . . . . . . . . . . . .
Granted . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Unvested at June 30, 2013 . . . . . . . . . . . . . . . . . . . . . . . . . . .

Number of
Restricted
Stock

—
50,000

50,000

Weighted-
Average
Exercise
Price

$ —
11.93

$11.93

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IMMUNOGEN, INC.

NOTES TO CONSOLIDATED FINANCIAL  STATEMENTS (Continued)

AS OF JUNE 30, 2013

B. Summary of Significant Accounting Policies (Continued)

Stock compensation expense related to stock options and restricted stock  awards  granted under  the

2006 Plan was $12.4 million, $9.9 million  and $5.5 million during  the fiscal years ended June 30,  2013,
2012, and 2011, respectively. As of June  30, 2013, the estimated  fair value of unvested  employee awards
was approximately $17.4 million, net  of  estimated  forfeitures. The  weighted-average remaining vesting
period for these awards is approximately  two years.

A summary of option activity for options  vested  during  the fiscal years ended June 30, 2013,  2012

and 2011 is presented below (in thousands):

Total fair value of options vested . . . . . . . . . . . . . . . . . .
Total intrinsic value of options exercised . . . . . . . . . . . . .
Cash received for exercise of stock options . . . . . . . . . . .

$9,670
6,737
4,026

$ 5,647
12,476
6,988

$3,427
3,467
2,719

Year Ended June 30,

2013

2012

2011

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, 2013
and 2012 and the Company’s net loss and unrealized gains on available-for-sale marketable  securities
for the year ended June 30, 2011.

Segment Information

During  the three fiscal years ended June 30,  2013, 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, 2013, 2012 and 2011  are  included  in the following table:

Collaborative Partner:

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

Year Ended June 30,

2013

2012

2011

6% 30% 41%
4% 15% 17%
5% 14% 9%
49% 16% 7%
30% 0% 0%
3% 23% 23%

There were no other customers of the  Company with  significant revenues  in the years ended

June 30, 2013, 2012 and 2011.

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NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

AS OF JUNE 30, 2013

B. Summary of Significant Accounting Policies (Continued)

Recent Accounting Pronouncements

In July 2013, the FASB issued guidance  to  address the  diversity in practice  related to the financial

statement presentation of unrecognized tax  benefits as  either a reduction of a deferred tax  asset or a
liability when a net operating loss carryforward, a similar  tax loss, or a tax  credit carryforward exists.
This guidance is effective prospectively for fiscal years, and interim  periods within those  years,
beginning after December 15, 2013. 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 Roche, through its Genentech unit, an  exclusive  license to the

Company’s maytansinoid TAP technology  for use  with antibodies or other  proteins that target  HER2,
such as trastuzumab. Under the terms  of this agreement,  Roche  has exclusive worldwide rights  to
develop and commercialize maytansinoid  TAP compounds targeting HER2. In February 2013, the  US
FDA granted marketing approval to  the  anti-HER2 TAP  compound  Kadcyla. 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, 2013,  the Company has  received  and recognized
$13.5 million and $10.5 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. Based on an evaluation of the effort contributed to the
achievement of this milestone, the Company  determined  this milestone was 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
$10.5 million non-refundable payment as revenue upon achievement of the milestone, which is included
in license and milestone fees for the  fiscal year ended  June 30, 2013. The next  potential milestone the
Company will be entitled to receive will be either a  $5 million regulatory  milestone for marketing
approval of Kadcyla in Europe or a $5  million regulatory milestone for marketing approval of Kadcyla
in Japan depending on which occurs  first.  Based on an evaluation  of  the effort contributed to the
achievement of these milestones, the Company  has determined these milestones  are not substantive.
The Company receives royalty reports  and payments related  to  sales of  Kadcyla from Roche one
quarter in arrears. In accordance with  the Company’s revenue recognition policy, $592,000 of royalties
on net  sales of Kadcyla for the period ended March  31, 2013 were recorded  in the Company’s fourth
quarter of fiscal 2013 and are included  in  royalty revenues for the fiscal year ended June 30,  2013.

Roche, through its Genentech unit, also  has licenses for the exclusive right  to  use the Company’s
maytansinoid TAP technology with antibodies  to  four undisclosed targets,  which were granted under  the

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NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

AS OF JUNE 30, 2013

C. Agreements (Continued)

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
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, 2013. 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

In September 2000, the Company entered into a  ten-year right-to-test agreement  with

Abgenix, Inc., which was later acquired by Amgen. The agreement provided Amgen  with the right  to
(a) test the Company’s maytansinoid TAP  technology with Amgen’s antibodies under  a right-to-test,  or
research, license, (b) take options, with  certain restrictions, to individual targets selected by Amgen on
either an exclusive and non-exclusive basis  for  specified option  periods and (c) upon exercise of those
options, take exclusive or non-exclusive  licenses  to  use the Company’s maytansinoid TAP technology  to
develop and commercialize products  for the specified  targets on  previously  agreed-upon terms.  The
Company received a $5 million technology access  fee in September 2000. For each exclusive
development and commercialization license taken, the Company is entitled to receive an exercise fee of
$1 million and up to a total of $34 million in milestone payments,  plus royalties on the commercial
sales of any resulting products. The total  milestones  per  exclusive development and  commercialization
license are categorized as follows: development milestones—$9  million; regulatory milestones—
$20 million; and sales milestones—$5 million. For each non-exclusive development  and
commercialization license taken, the  Company is entitled to receive an exercise fee of $500,000  and up
to a total of $17 million in milestone  payments, plus  royalties on  the commercial sales of any resulting
products. The total milestones per non-exclusive development  and  commercialization  license are
categorized as follows: development milestones—$4.5 million; regulatory milestones—$10 million; and
sales milestones—$2.5 million. Amgen  is responsible  for the  manufacturing,  product development  and
marketing of any products resulting from  the agreement.  Amgen no longer has the right to take
additional options under the agreement and there  are no unexercised options outstanding.

Under the 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

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NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

AS OF JUNE 30, 2013

C. Agreements (Continued)

fee of $500,000. The Company has deferred each exercise fee and  is recognizing these amounts as
revenue ratably over the respective estimated periods of its substantial involvement.

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

the exclusive development and commercialization licenses became effective,  which triggered  two
$1 million milestone payments to the Company.  These  payments are included in license  and milestone
fees for the year ended June 30, 2012.  At  the time of execution of each  of these  exclusive  development
and commercialization licenses, 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 manufacturing  of these  product candidates, these milestones were
deemed substantive. The next potential milestone the Company will  be  entitled to receive  under either
of these  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 development  milestone for IND approval
which  will result in a $1 million payment  and a $500,000  milestone payment, respectively, being due to
the Company. 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.

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 TAP technology in  the creation of products developed to these targets.
The product candidates (targets) as of  June 30, 2013  in the collaboration  include SAR3419 (CD19),
SAR650984 (CD38), SAR566658 (DS6, also known as CA6) and  two  earlier-stage compounds that have
yet to be disclosed.

For each of the targets included in the collaboration at this time,  the Company is entitled to
receive up to a total of $21.5 million  in milestone payments,  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,  2013, the Company  has received
and recognized an aggregate of $16.5 million in  milestone payments for  compounds covered  under this
agreement now or in the past, including 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,  a
$3 million milestone payment related  to  the initiation of a  Phase IIb clinical  trial  (as  defined  in the
agreement) for SAR3419, which is included in  license and milestone  fee revenue for the year ended
June 30, 2012, as well as a $1 million milestone payment earned in  September 2010 related to the
initiation of Phase I clinical testing of  SAR566658 which is included in license and milestone fee
revenue for the year ended June 30, 2011. At  the time  of execution of this agreement, there was
significant uncertainty as to whether  these received  and recognized milestones  would be achieved.  In

83

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NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

AS OF JUNE 30, 2013

C. Agreements (Continued)

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. The next  potential  milestone the
Company will be entitled to receive with respect  to  both SAR566658 and SAR650984 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 SAR3419 will be 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 each of the unidentified targets  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 separate right-to-test  agreement with  Sanofi. The
agreement provides Sanofi with the right  to (a) test  the Company’s maytansinoid  TAP technology with
Sanofi’s antibodies to targets that were  not  included in  the collaboration agreement  described above
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 TAP technology  to  develop and commercialize products
directed to the specified targets on terms agreed upon  at the  inception of the right-to-test agreement.
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.  No development  and
commercialization license has yet been taken under this  agreement. Execution  of the first license will
entitle the Company to receive an exercise fee in  the amount of $2 million. Sanofi is responsible for
the manufacturing, product development  and marketing of any  products resulting  from the agreement.

The Company received an aggregate 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 of which
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
Sanofi in August 2011for its final three-year term by  payment of a  $2 million  fee.  The  Company has
deferred the $2 million extension fee  and  is recognizing this  amount as revenue over the period during
which  Sanofi can take an option for a  development and  commercialization license.

Biotest

In July 2006, the Company granted Biotest an  exclusive  development and commercialization
license to our maytansinoid TAP technology for use  with antibodies that target  CD138. The product
candidate BT-062 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

84

IMMUNOGEN, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

AS OF JUNE 30, 2013

C. Agreements (Continued)

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 BT062 which triggered a  $500,000  milestone payment to the  Company. At the time of
execution of this agreement, there was significant  uncertainty as to whether this  received  and
recognized milestone would be achieved. In consideration of this, as well as the  Company’s past
involvement in the research and manufacturing  of this  product candidate, this  milestone was deemed
substantive. The next potential milestone the Company  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  this milestone would be achieved. In consideration of this, as  well
as the Company’s past involvement in the  research and manufacturing of  this product, this  milestone
was deemed substantive.

The agreement also provides 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. 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
costs of product development and commercialization  in the U.S.  along with the profit, if  any, from
product  sales in the U.S.

Bayer HealthCare

In October 2008, the Company granted Bayer HealthCare an exclusive development and

commercialization license to the Company’s  maytansinoid TAP 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,  2013, 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.

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NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

AS OF JUNE 30, 2013

C. Agreements (Continued)

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
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. This change in estimate resulted in an  increase to license and  milestone fees of
approximately $1.2 million for the fiscal  year ending June 30,  2012 compared to amounts  that  would
have been recognized pursuant to the  Company’s previous  estimate.

Novartis

In October 2010, the Company entered  into  a three-year right-to-test agreement with  Novartis
Institutes for BioMedical Research, Inc.  (Novartis). The agreement provides  Novartis with the  right to
(a) test the Company’s TAP technology with individual  antibodies selected by Novartis under  a
right-to-test, or research, license, (b)  take exclusive options, with  certain restrictions,  to  individual
targets selected by Novartis for specified option periods and (c) upon exercise  of  those options, take
exclusive licenses to use the Company’s TAP technology to  develop and commercialize  products for a
specified number of individual targets on  terms  agreed upon  at  the  inception of the right-to-test
agreement. The initial three-year term  of the right-to-test agreement may  be  extended by Novartis for
up to two additional one-year periods by  payment of  additional consideration. The  terms of the
right-to-test agreement require Novartis to exercise  its options for the development  and
commercialization licenses by the end  of  the term of  the research license.  The  Company received a
$45 million upfront payment in connection  with the  execution  of  the right-to-test agreement, and for
each  development and commercialization license for a specific  target, the Company is entitled to
receive an exercise fee of $1 million and  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 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.

Effective March 29, 2013, the Company and Novartis amended the right-to-test agreement  so that

Novartis can take a license to develop  and commercialize products directed at  two pre-defined  and
related undisclosed 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 be converted to an
exclusive target by notice and payment to us of an  agreed upon  fee of at least  $5 million, depending on
specific  circumstances. The Company was entitled  to  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

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IMMUNOGEN, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

AS OF JUNE 30, 2013

C. Agreements (Continued)

milestone payments if Novartis discontinues the  development of a specified  product under certain
circumstances.

In connection with the amendment, on March 29,  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  was entitled to 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
milestones—$22.5 million; regulatory  milestones—$115.5  million; and sales milestones—$100 million),
depending on the composition of any resulting products.  The  first potential milestone the  Company will
be entitled to receive will be a $5.0 million development milestone  for commencement of a  Phase I
clinical trial. 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 manufacturing of this product  candidate, this milestone was  deemed substantive.
Additionally, the Company is entitled  to  receive royalties  on product sales, if  any. Novartis  also has  the
right to convert the noted non-exclusive license to an  exclusive  license,  in which case  the Company
would be entitled to receive a conversion fee and, depending on the  composition  of resultant  products,
an upward adjustment on milestone payments.

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

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NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

AS OF JUNE 30, 2013

C. Agreements (Continued)

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
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 TAP 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. 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.

The total arrangement consideration  of $55.2 million (which comprises the $45 million upfront

payment, the amendment fee of $3.5  million, the exercise fee for each license, and the expected fees
for the research services to be provided under the  remainder of the arrangement) was allocated to the
deliverables based on the relative selling price method as follows: $50.4  million  to  the development and
commercialization licenses; $4.1 million  to  the rights to future technological improvements; and
$710,000 to the research services. Upon  execution  of the development and commercialization  license
taken by Novartis in March 2013, the  Company recorded $11.1 million of the $50.4 million  of the
arrangement consideration outlined above, which is included in  license  and milestone  fee  revenue for
the fiscal year ended June 30, 2013. 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 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  as license revenue an  equal
amount of the total remaining $39.3  million  of  arrangement consideration  allocated to the  development
and commercialization licenses as each  individual license is  delivered to Novartis  upon Novartis’

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NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

AS OF JUNE 30, 2013

C. Agreements (Continued)

exercise of its remaining options to such licenses. The Company does not control when Novartis 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.

Lilly

In December 2011, the Company entered into a three-year right-to-test  agreement with  Eli Lilly
and Company (Lilly). The agreement provides Lilly with  the right to (a) take exclusive options,  with
certain restrictions, to individual targets selected by Lilly  for specified  option  periods, (b) test the
Company’s maytansinoid TAP technology  with  Lilly’s antibodies directed to the optioned targets under
a right-to-test, or research, license, and  (c) upon  exercise  of  those options, take exclusive licenses to use
the Company’s maytansinoid TAP technology to develop and commercialize products for a specified
number of individual targets on terms  agreed upon at the inception  of  the right-to-test agreement. The
terms of the right-to-test agreement require Lilly to exercise its  options  for the development and
commercialization licenses by the end  of  the term of  the research license.  In August 2013,  Lilly took its
first exclusive license to a single target.

The Company received a $20 million  upfront payment  in connection with the execution of  the

right-to-test agreement, and for the first development and commercialization license taken, which
occurred in August 2013, 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.  For each subsequent
development and commercialization license taken, the Company is entitled to receive an exercise fee in
the amount of $2 million and up to a total of $199  million  in milestone payments, plus  royalties on  the
commercial sales of any resulting products. The total milestones are categorized as  follows:
development milestones—$30.5 million  for the first development  and commercialization license  and
$29 million for each subsequent license; regulatory milestones—$70 million;  and sales milestones—
$100 million. The next payment the Company could  receive would either  be a $5 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. The
Company also is 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.

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

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NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

AS OF JUNE 30, 2013

C. Agreements (Continued)

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 TAP 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,
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.  over 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. The
estimated selling price of the cytotoxic  agent was based on  third-party evidence  given market rates  for

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NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

AS OF JUNE 30, 2013

C. Agreements (Continued)

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. 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 Lilly upon  Lilly’s exercise of its
options to such licenses. At the time  the first 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 be required  to  reassess the
estimated term at each subsequent reporting period. The Company does not control  when Lilly  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 and revenue  from the delivery
of cytotoxic agents as the related services  and cytotoxic agents are delivered.

No license revenue has been recognized  related to this agreement through  June 30, 2013 as  the
options to take development and commercialization licenses  were  not  considered to be substantive and
no development and commercialization licenses  had been delivered  at  this time. Accordingly, the  entire
$20 million upfront payment is included in long-term deferred revenue at  June  30, 2013.

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. Under the  terms of the
agreement, the Company received an upfront payment  of $1 million upon execution of the agreement.

In December 2007, the Company licensed  from Janssen the exclusive, worldwide  right to develop

and commercialize a TAP compound, IMGN388, that consists of an (cid:2)v  integrin-targeting antibody
developed by them and one of the Company’s maytansinoid cell-killing  agents. This  license reallocated
the parties’ respective responsibilities  and financial obligations from  the license  referenced  above. In
November 2011, the Company announced  its  decision  to  discontinue  development of IMGN388. During
the first quarter of fiscal 2013, the 2007 license agreement was terminated with rights to the  product
candidate reverting back to Janssen. The  remaining  $241,000 of the  $1 million upfront fee received

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NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

AS OF JUNE 30, 2013

C. Agreements (Continued)

from Janssen upon execution of the 2004  license agreement is included in  long-term deferred  revenue
at June  30, 2013.

Effective July 2011, Biogen Idec terminated its exclusive license to the Company’s TAP  technology

to develop and commercialize therapeutic compounds to the target  Cripto. This license was granted
pursuant to the Development and License  Agreement between  the Company and Biogen Idec dated
October 1, 2004. As a result of the termination, during the first  quarter of  fiscal 2012, the Company
recognized the remaining $270,000 of the  $1 million upfront fee received from Biogen Idec  upon
execution of the license which had been previously  deferred.

D. Marketable Securities

As of June 30, 2013 and 2012, $195.0  million and $160.9 million, respectively, in  cash and money
market funds consisting principally of  U.S.  Government-issued securities  and high  quality, short-term
commercial paper were classified as cash and cash equivalents.

During  fiscal year  2011, the Company  sold  the remaining marketable securities held in  its
investment portfolio at June 30, 2010, resulting in realized gains of  $347,000 and realized  losses of
$(6,000). In 2013 and 2012, the Company  had no realized losses or  gains.

E. Property and Equipment

Property and equipment consisted of  the following at June 30, 2013 and 2012 (in thousands):

June 30,

2013

2012

Leasehold improvements . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Machinery and equipment . . . . . . . . . . . . . . . . . . . . . . . . . . .
Computer hardware and software . . . . . . . . . . . . . . . . . . . . . .
Furniture and fixtures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Assets under construction . . . . . . . . . . . . . . . . . . . . . . . . . . . .

$ 26,777
14,741
4,894
1,540
814

$ 25,661
13,808
4,168
1,315
660

Less accumulated depreciation . . . . . . . . . . . . . . . . . . . . . . . .

$ 48,766
(37,983)

$ 45,612
(33,979)

Property and equipment, net

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

$ 10,783

$ 11,633

Depreciation expense was approximately $4.6 million, $4.6 million and $4.9  million for the years

ended June 30, 2013, 2012 and 2011,  respectively.

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NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

AS OF JUNE 30, 2013

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,

2013

2012

2011

Loss before income tax expense . . . . . . . . . . . . . . .

$(72,811) $(73,319) $(58,274)

Expected tax benefit at 34% . . . . . . . . . . . . . . . . . .
Permanent differences . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . .
State tax benefit net of federal benefit
Increase in valuation allowance, net . . . . . . . . . . . .
Expired loss and credit carryforwards . . . . . . . . . . .
Other . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

$(24,756) $(24,928) $(19,813)
—
1,469
(1,815)
(4,204)
16,410
26,574
5,610
1,089
(392)
—

1,540
(3,921)
25,192
1,945
—

Benefit for income taxes . . . . . . . . . . . . . . . . . . . .

$

— $

— $

—

At June  30, 2013, the Company has net operating loss carryforwards of approximately

$329.5 million available to reduce federal  taxable income, if any, that expire in 2014  through 2033 and
$187.4 million available to reduce state taxable income, if any,  that expire  in fiscal 2014 through  fiscal
2033. Included in the federal and state  carryforwards is $18.5 million  and $15.8 million,  respectively,
related to deductions from the exercise  of  stock options and  the  related  tax benefit  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 research tax credits of approximately $14.8 million available to
offset federal and state income taxes, which  expire beginning in  fiscal 2014. 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

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IMMUNOGEN, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

AS OF JUNE 30, 2013

F.

Income Taxes (Continued)

purposes. Significant components of the Company’s deferred tax assets as  of June  30, 2013 and 2012
are as follows (in thousands):

June 30,

2013

2012

Net operating loss carryforwards . . . . . . . . . . . . . . . . . . . . .
Research and development tax credit carryforwards . . . . . . .
Property and other intangible assets . . . . . . . . . . . . . . . . . . .
Deferred revenue . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Stock-based compensation . . . . . . . . . . . . . . . . . . . . . . . . . .
Deferred lease incentive . . . . . . . . . . . . . . . . . . . . . . . . . . .
Other liabilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

$ 121,937
12,806
2,077
25,484
5,759
4,771
508

$ 98,601
10,393
1,486
28,325
3,302
5,100
512

Total deferred tax assets . . . . . . . . . . . . . . . . . . . . . . . . . . .
Valuation allowance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

$ 173,342
(173,342)

$ 147,719
(147,719)

Net deferred tax assets . . . . . . . . . . . . . . . . . . . . . . . . . . . .

$

— $

—

The valuation allowance increased by $25.6  million  during  2013 due primarily to the additional  net

loss recognized during the year, partially offset by the expiration of net  operating loss carryforwards.

Utilization of the NOL and R&D 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 R&D  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. The Company has not currently completed  a study to assess  whether  a change of control
has occurred or whether there have been multiple changes of control since its  formation due to the
significant complexity, costs associated  with such  study and the possibility that there could be additional
changes in control in the future. If the Company has  experienced a change  of control at  any time since
its  formation, utilization of its NOL or R&D  credit carry  forwards  would be subject to an  annual
limitation under Section 382 which is  determined by first multiplying the  value of  the Company’s stock
at the time of the ownership change  by  the applicable long-term  tax-exempt  rate, and then could be
subject to additional adjustments, as  required. Any limitation  may result in  expiration of a  portion of
the NOL or R&D credit carry forwards  before utilization.  Further,  until  a study is completed  and any
limitation known, no amounts are being presented  as an uncertain tax position. The Company  does not
expect to have any taxable income for  at  least the  next several  years.

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

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IMMUNOGEN, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

AS OF JUNE 30, 2013

F.

Income Taxes (Continued)

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  carryforwards are subject to adjustment  by
state and federal taxing authorities, commencing  when those losses are  utilized  to  reduce taxable
income.

Included in other (expense) income,  net  for the  fiscal year ended June 30, 2011  is $1.2  million of

federal grant funding the Company was  awarded under the  Patient Protection and Affordable Care Act
of 2010 to develop new anticancer therapies.

G. Capital Stock

Sale of Common Stock

On May 19, 2011, the Company filed  a Registration Statement on Form  S-3 with the  Securities

and Exchange Commission. Pursuant  to  the shelf  registration statement, in May 2011 and June 2011,
the Company issued and sold a total  of 7,800,000 shares of its  common stock at $12.00 per share
through a public offering resulting in gross proceeds of $93.6  million. Pursuant to the shelf registration
statement filed in May 2011, in July  2012, the  Company issued and sold a total of  6,250,000 shares  of
its  common stock at $16.00 per share  through a public offering resulting  in gross proceeds of
$100 million.

Common Stock Reserved

At June  30, 2013, the Company has reserved 12.57 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, 2013, the 2006 Plan was the only employee share-based compensation plan  of  the

Company. During the year ended June 30,  2013, holders of  options  issued under the 2006  Plan  and the
Former Plan exercised their rights to acquire  an aggregate  of  666,000 shares  of  common stock at  prices
ranging from $2.91 to $15.20 per share. The  total  proceeds  to  the  Company from these option exercises
were approximately $4.0 million.

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IMMUNOGEN, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

AS OF JUNE 30, 2013

G. Capital Stock (Continued)

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, 2013, 2012 and 2011:

June 30, 2013 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
June 30, 2012 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
June 30, 2011 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4,202
3,416
3,834

$7.97
$6.34
$5.25

Exercisable
(in thousands)

Weighted-
Average
Exercise Price

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
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, 2013, 2012 and 2011, the  Company recorded approximately
$(1,000), $29,000, and $44,000 in (expense  reduction) compensation expense,  respectively, related to
approximately 6,000, 6,000, and 15,000 stock units outstanding, respectively, 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.  Pursuant to the 2001  Plan,  in
November 2011, the Company paid a  retiring director approximately $115,000 to settle outstanding
stock units.

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

96

IMMUNOGEN, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

AS OF JUNE 30, 2013

G. Capital Stock (Continued)

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
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

97

IMMUNOGEN, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

AS OF JUNE 30, 2013

G. Capital Stock (Continued)

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, in November 2011,  the Company issued two retiring  directors an
aggregate 46,298 shares of common stock  of  the Company  to  settle outstanding deferred  share units.

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.

(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. These options  will  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 41,805, 33,187 and 49,688 options in fiscal years 2013,  2012
and 2011, 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 and the 2004 Director Plan,  as

amended, the Company recorded approximately:

(cid:129) $351,000 in compensation expense during the year ended  June  30, 2013 related to the issuance

of 26,000 deferred share units and 251,000 deferred  share units previously  issued under the  2004
Director Plan;

(cid:129) $314,000 in compensation expense during the year ended  June  30, 2012 related to the issuance

of 33,000 deferred share units and 264,000 deferred  share units previously  issued under the  2004
Director Plan; and

(cid:129) $326,000 in compensation expense during the year ended  June  30, 2011 related to the issuance

of 39,000 deferred share units and 225,000 deferred  share units previously  issued under the  2004
Director Plan.

98

IMMUNOGEN, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

AS OF JUNE 30, 2013

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. The Company uses  this space for its corporate headquarters  and other
operations. The initial term of the lease is for  twelve  years  with an  option for the Company to extend
the lease for two additional terms 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 2009 for 14,100 square feet of this space
in Waltham through January 2015, with  the sublessee  having a conditional  option to extend the term
for an additional two years.

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 initial term of the sublease is  for three years  with a conditional  option for the
Company to extend the lease through October 2017. 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.

As part of the 2007 lease agreement, the  Company received a  construction allowance of up  to

approximately $13.3 million to build out  laboratory and office space  to  the Company’s  specifications.
After completion, the Company had  recorded $12.0 million of leasehold improvements under  the
construction allowance. The Company received $10.8 million from  the  landlord  and paid  out the  same
amount towards these leasehold improvements. The remaining balance of the  improvements was  paid
directly by the landlord. The lease term  began  on October 1, 2007,  when the  Company obtained
physical control of the space in order  to  begin construction.

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 is 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.

Facilities rent expense, net of sublease income, was  approximately  $4.8 million,  $4.8 million and

$4.6 million during fiscal years 2013,  2012 and  2011, respectively.

99

IMMUNOGEN, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

AS OF JUNE 30, 2013

H. Commitments and Contingencies (Continued)

As of June 30, 2013, 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):

2013 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2014 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2015 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2016 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2017 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Thereafter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

$ 6,636
6,780
6,549
6,624
6,831
10,029

Total minimum lease payments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Total minimum rental income from subleases . . . . . . . . . . . . . . . . . . . . . .

$43,449
(1,088)

Total minimum lease payments, net . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

$42,361

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. During the first quarter of fiscal  2013, the Company’s
license agreement with Janssen Biotech was terminated and, accordingly,  the Company  is no  longer
obligated to make $41.0 million of potential future success-based milestone  and third-party payments
under such agreement. As of June 30, 2013,  the maximum amount that may be payable in the  future
under the Company’s current collaborative  agreements is  $2.0 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  2013, 2012 and 2011,  the
Company’s contributions to the 401(k)  Plan totaled  approximately  $593,000, $548,000, and $467,000,
respectively.

100

IMMUNOGEN, INC.

NOTES TO CONSOLIDATED FINANCIAL  STATEMENTS (Continued)

AS OF JUNE 30, 2013

J. Quarterly Financial Information  (Unaudited)

Fiscal Year 2013

First Quarter
Ended

Second Quarter
Ended

Third Quarter
Ended

September 30, 2012 December 31, 2012 March 31, 2013

Fourth Quarter
Ended
June 30, 2013

(In thousands, except per share data)

Revenues:

License and milestone fees . . . . . . . . .
Research and development support . . .
Clinical materials revenue . . . . . . . . .
Royalty revenue . . . . . . . . . . . . . . . .

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

Expenses:

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

Total expenses . . . . . . . . . . . . . . . .

Loss from operations . . . . . . . . . . . . . .
. . . . . . .

Other income (expense), net

$

933
1,377
1,781
—

4,091

23,700
5,639

29,339

(25,248)
56

$

429
2,036
147
—

2,612

21,656
5,464

27,120

(24,508)
115

$22,010
2,257
734
—

25,001

21,318
4,995

26,313

(1,312)
(39)

$

855
2,203
181
592

3,831

20,399
5,373

25,772

(21,941)
66

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

$(25,192)

$(24,393)

$ (1,351)

$(21,875)

Basic and diluted net loss per

common share . . . . . . . . . . . . . . . .

$

(0.30)

$

(0.29)

$ (0.02)

$

(0.26)

Fiscal Year 2012

First Quarter
Ended

Second Quarter
Ended

Third Quarter
Ended

September 30, 2011 December 31, 2011 March 31, 2012

Fourth Quarter
Ended
June 30, 2012

(In thousands, except per share data)

Revenues:

License and milestone fees . . . . . . . . .
Research and development support . . .
Clinical materials reimbursement . . . .

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

Expenses:

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

Total expenses . . . . . . . . . . . . . . . .

Loss from operations . . . . . . . . . . . . . .
Other income, net . . . . . . . . . . . . . . .

$ 1,187
1,068
281

2,536

17,161
4,841

22,002

(19,466)
(17)

$ 6,025
945
647

7,617

15,559
4,834

20,393

(12,776)
23

$

999
1,320
933

3,252

16,933
5,021

21,954

(18,702)
33

$

950
1,184
818

2,952

19,539
5,726

25,265

(22,313)
(101)

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

$(19,483)

$(12,753)

$(18,669)

$(22,414)

Basic and diluted net loss per

common share . . . . . . . . . . . . . . . .

$

(0.26)

$

(0.17)

$

(0.24)

$

(0.29)

101

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, 2013. 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.

Based on this assessment, management has concluded that, as of  June  30, 2013 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,  2013. This  report appears
immediately below.

102

(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, 2013,

based on criteria established in Internal Control—Integrated  Framework  issued by the Committee of
Sponsoring Organizations of the Treadway Commission (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, 2013  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,
2013 and 2012, 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, 2013 and
our  report dated August 29, 2013 expressed an unqualified opinion thereon.

/s/ ERNST & YOUNG LLP

Boston, Massachusetts
August 29, 2013

103

(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,
2013 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.

104

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
2013 annual meeting of shareholders,  which will be filed  with the  Securities  and Exchange  Commission
not later than October 28, 2013 (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.

105

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) The following schedule is filed as part of this Annual Report on  Form  10-K:

Schedule II—Valuation and Qualifying  Accounts for the years ended  June 30, 2013, 2012  and 2011.

(3) See Exhibit Index following the  signature page  to  this  Annual  Report on  Form  10-K.

106

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 29, 2013

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/ GREGORY D. PERRY

Gregory D. Perry

/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/ MARK SKALETSKY

Mark Skaletsky

/s/ JOSEPH VILLAFRANCA PH.D.

Joseph  Villafranca, Ph.D.

/s/ RICHARD WALLACE

Richard Wallace

President, Chief Executive Officer and Director

(Principal Executive Officer)

August 29, 2013

Executive Vice President and

Chief Financial Officer
(Principal Financial and Accounting Officer)

August  29, 2013

Chairman of the Board of Directors

August  29, 2013

Director

Director

Director

Director

Director

Director

Director

Director

107

August 29, 2013

August 29, 2013

August 29, 2013

August 29, 2013

August 29, 2013

August 29, 2013

August 29, 2013

August 29, 2013

EXHIBIT INDEX

Filed
with this
Form 10-K Form

Incorporated by Reference

Filing Date
with SEC

Exhibit
Number

10-Q

10-Q

8-K

April  30, 2010

January 30,  2013

April  6,  2007

S-1 November 15,  1989
(File No. 33-31219)

3.1

3.1

3.1

4.2

S-1 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

108

Exhibit
Number

10.1(i)

10.2

10.3*

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

License Agreement dated  effective May  2, 2000  by
and between the  Registrant and Genentech,  Inc.

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

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*

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.)

10.4(a)* Amendment  No. 1, dated as  of August 31,  2006,  to
the Collaboration and License Agreement  between
the Registrant and sanofi-aventis U.S.  LLC

10-Q

January  30, 2013

10.11

10-Q November 14,  2003

10.1

10-Q November 3,  2006

10.1

10.4(b)* Amendment  No. 2, dated as  of October  11,  2007,

10-Q

February  7, 2008

10.4

to the Collaboration and License Agreement
between the Registrant  and sanofi-aventis  U.S. LLC

10.4(c)*

Amendment  No. 3, dated as  of August 31,  2008,  to
the Collaboration and License Agreement  between
the Registrant and sanofi-aventis U.S.  LLC

10.5*

10.6*

Option and License Agreement dated as  of
December 21, 2006 by and between the  Registrant
and sanofi-aventis U.S. LLC

Collaborative Development and License  Agreement
dated as of July 7, 2006 by and between  the
Registrant and Biotest AG

10-Q

February  6, 2009

10.7

10-Q

February  8, 2007

10.2

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

10.7*

Development and License Agreement  dated  as of
October 20, 2008 by and  between the  Registrant
and Bayer HealthCare AG

10-Q/A

October 10,  2012

10.1

109

Exhibit
Number

10.8*

10.8(a)*

10.9*

10.10*

Exhibit Description

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

10.11†

Restated Stock Option Plan

10.11(a)† Form of Incentive Stock Option Agreement

10.11(b)† Form of Non-Qualified Stock Option Agreement

10.12†

2006 Employee, Director  and Consultant Equity
Incentive Plan, as amended  and restated  through
November 13, 2012

Filed
with this
Form 10-K Form

Incorporated by Reference

Filing Date
with SEC

Exhibit
Number

10-Q/A

October  10,  2012

10.2

10-Q

May 6,  2013

10.1

10-Q

February  8, 2011

10.1

10-Q/A

October  10,  2012

10.3

8-K

8-K

8-K

February  7, 2006

February  7, 2006

February  7, 2006

8-K November 16,  2012

10.1

10.2

10.3

10.1

10.12(a)† Form of Incentive Stock Option Agreement  for

S-8 November  15, 2006

99.4

Executives

10.12(b)† Form of Non-Qualified Stock Option Agreement

S-8 November 15,  2006

99.5

for Executives

10.12(c)† Form of Non-Qualified Stock Option Agreement

10-Q

October 29,  2010

10.1

for Directors

10.12(d)† Form of Director Deferred  Stock  Unit Agreement

10-Q

October 29,  2010

10.1

10.12(e)† Form of Incentive Stock Option Agreement  for all

10-K

August 29,  2012

10.14(g)

employees (including executives)

10.12(f)† Form of Non-Qualified Stock Option Agreement
for all employees (including executives)

10-K

August 29,  2012 10.14(h)

10.12(g)† Form of Non-Qualified Stock Option Agreement

10-K

August 29,  2012

10.14(i)

for Directors

10.12(h)† Form of Restricted Stock Agreement for  all
employees (including executives)

10.13†

2001 Non-Employee Director Stock  Plan

10.14†

10.15†

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

110

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

Exhibit
Number

10.16†

10.17†

10.18†

10.19†

10.20†

10.21†

10.22†

10.23†

Exhibit Description

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
James J. O’Leary

Change in Control Severance  Agreement dated as
of November 30, 2012 between the  Registrant  and
Gregory D. Perry

Change in Control Severance  Agreement dated as
of November 30, 2012 between the  Registrant  and
Peter Williams

Change in Control Severance  Agreement dated as
of November 30, 2012 between the  Registrant  and
Theresa G. Wingrove

Filed
with this
Form 10-K Form

Incorporated by Reference

Filing Date
with SEC

Exhibit
Number

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

10.5

10-Q

January  30, 2013

10.6

10-Q

January  30, 2013

10.7

10-Q

January  30, 2013

10.8

10.24†

Compensation  Policy for  Non-Employee  Directors,
as amended through September 22, 2010

10-Q

October 29,  2010

10.1

10.25†

Summary of Annual Executive Bonus  Program

10-Q November  7,  2007

10.1

10.26†

10.27†

10.28†

21

23

31.1

31.2

Employment Agreement  dated  as of July 27, 2011
between the Registrant  and Gregory D.  Perry

Employment offer  letter between the Registrant
and Charles Q. Morris

Employment Agreement  dated  as of November  26,
2012 between the Registrant and Charles  Q. Morris

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

X

X

X

10-K

August 29,  2011

10.26

10-Q

January  30, 2013

10.9

10-Q

January  30, 2013

10.10

10-K

August  30, 2007

21

111

Exhibit
Number

32

Exhibit Description

Filed
with this
Form 10-K Form

Incorporated by Reference

Filing Date
with SEC

Exhibit
Number

Certifications of Chief Executive Officer and Chief
Financial Officer pursuant to Section 906  of the
Sarbanes-Oxley Act of 2002

X

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

*

†

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.

112

IMMUNOGEN, INC.

SCHEDULE II—VALUATION AND QUALIFYING ACCOUNTS

(In thousands)

COLUMN A—DESCRIPTION

Inventory Valuation Allowance

Year End June 30, 2013 . . . . . . . . . . . . . . . . . . .
Year End June 30, 2012 . . . . . . . . . . . . . . . . . . .
Year End June 30, 2011 . . . . . . . . . . . . . . . . . . .

COLUMN B

COLUMN C—
ADDITIONS

COLUMN D

COLUMN  E

Balance at
Beginning
of Period

$1,291
$1,993
$ 939

Charged
to Costs
and
Expenses

$ 798
$ 786
$1,664

Use of
Zero
Value
Inventory

$(1,279)
$(1,488)
$ (610)

Balance  at
End of
Period

$ 810
$1,291
$1,993

113

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 29, 2013

/s/ DANIEL M. JUNIUS

Daniel M. Junius
President and Chief Executive Officer
(Principal Executive Officer)

EXHIBIT 31.2

CERTIFICATIONS UNDER SECTION 302

I, Gregory D. Perry, 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 29, 2013

/s/ GREGORY D. PERRY

Gregory D. Perry
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, 2013  (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 29, 2013

/s/ DANIEL M. JUNIUS

Daniel M. Junius
President and Chief Executive Officer
(Principal Executive Officer)

Dated: August 29, 2013

/s/ GREGORY D. PERRY

Gregory D. Perry
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.

(This page has been left blank intentionally.)

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,  2008 through June 30,  2013 (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.

600.00

500.00

400.00

300.00

200.00

100.00

0.00

2008

2009

2010

2011

2012

2013

ImmunoGen Inc.

NASDAQ Stock Market (US Companies)

NASDAQ Pharmaceutical Index

22AUG201308224832

IMMUNOGEN, INC.
. . . . . . . . . . . . . . . . . . . . . . . . . . $100.00 $281.68 $302.91 $398.43 $547.14 $542.24
NASDAQ STOCK MARKET  INDEX  (U.S.) . . . . . . . . . . $100.00 $81.85 $ 95.01 $126.63 $137.96 $162.34
NASDAQ PHARMACEUTICAL STOCKS TOTAL

RETURN INDEX * . . . . . . . . . . . . . . . . . . . . . . . . . . $100.00 $97.73 $100.83 $130.95 $153.72 $212.53

2008

2009

2010

2011

2012

2013

*

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, 2008 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
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
Senior Vice President,
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.

Mark Skaletsky
Chairman and Chief Executive Officer,
Fenway Pharmaceuticals, Inc.

Joseph J. Villafranca, PhD
President, 
BioPharmaceutical Consultants, LLC

Richard J. Wallace
Former Senior Vice President
Research and Development, 
GlaxoSmithKline plc.

Corporate Officers
Daniel M. Junius
President and 
Chief Executive Officer

John M. Lambert, PhD
Executive Vice President and 
Chief Scientific Officer

Charles Q. Morris, MB, ChB, MRCP (UK)
Executive Vice President and 
Chief Development Officer

Godfrey Amphlett, PhD
President, Process and Analytical 
Development

Craig Barrows
Vice President, General Counsel 
and Secretary

Robert J. Lutz, PhD
Vice President, Translational Research 
and Development

James J. O’Leary, MD
Vice President and 
Chief Medical Officer

Peter J. Williams
Vice President, 
Business Development

Theresa G. Wingrove, PhD
Vice President, 
Regulatory Affairs

Corporate Headquarters
ImmunoGen, Inc.
830 Winter Street
Waltham, MA 02451
781.895.0600
www.immunogen.com

Annual Meeting
11:00 AM on November 12, 2013
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, 2013 and other reports filed with the Securities and Exchange Commission.

Kadcyla®, Herceptin®, Erbitux®, and Vectibix® are registered trademarks of their respective owners.

Immun_AnnReprt_2013_r5_PRODpaths.pdf   4   9/23/13   12:38 PM

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