Document:

Exhibit
10.1

EXECUTION COPY

LICENSE AGREEMENT

This
License Agreement (the “Agreement”) is made effective as of April 27, 2005 (the
“Effective Date”) by and between GENENTECH, INC., a Delaware corporation having
its principal business office at 1 DNA Way, South San Francisco, California
94080 (“GENENTECH”), and IMMUNOGEN, INC., a Massachusetts corporation with its
principal place of business at 128 Sidney Street, Cambridge, Massachusetts
02139 (“IMMUNOGEN”).  GENENTECH and
IMMUNOGEN are each hereafter referred to individually as a “Party” and together
as the “Parties”.

WHEREAS,
the Parties entered into the Heads of Agreement (defined below) pursuant to
which IMMUNOGEN granted GENENTECH the right to obtain up to [***] exclusive
options at any given time to obtain an exclusive license to use IMMUNOGEN’s
proprietary maytansinoid conjugation technology with certain proprietary
antibodies of GENENTECH and other binding proteins relating thereto that bind
to any antigen target selected by GENENTECH and determined by IMMUNOGEN to be
available for licensing as described more fully in the Heads of Agreement; and

WHEREAS,
pursuant to the Heads of Agreement, GENENTECH was granted an Exclusive Target
Option (as defined in the Heads of Agreement) with respect to [***] and has
exercised such Exclusive Target Option pursuant to the terms set forth in the
Heads of Agreement, resulting in the grant of an exclusive license from
IMMUNOGEN to GENENTECH on the terms set forth in the Heads of Agreement; and

WHEREAS,
pursuant to the Heads of Agreement, the Parties have agreed to enter into an
agreement setting forth the detailed terms of the exclusive license from
IMMUNOGEN to GENENTECH.

NOW,
THEREFORE, in consideration of the mutual covenants contained herein, and for
other good and valuable consideration, the receipt and adequacy of which are
hereby acknowledged, the Parties hereby agree as follows:

1. 
DEFINITIONS

Whenever used in the Agreement with an initial capital
letter, the terms defined in this Section 1 shall have the meanings specified.

Portions
of this Exhibit were omitted and have been filed separately with the Secretary
of the Commission pursuant to the Company’s application requesting confidential
treatment under Rule 24b-2 of the Securities Exchange Act of 1934.

1.1.                              “Adverse Event” shall mean any untoward medical occurrence in a patient or
subject who is administered a Licensed Product, whether or not considered
related to the Licensed Product, including, without limitation, any undesirable
sign (including abnormal laboratory findings of clinical concern), symptom or
disease temporally associated with the use of such Licensed Product.

1.2.                              “Affiliate” shall mean any
corporation, firm, limited liability company, partnership or other entity which
directly or indirectly controls or is controlled by or is under common control
with a Party to this Agreement.  For
purposes of this Section 1.2, “control” means ownership, directly or indirectly
through one or more Affiliates, of fifty percent (50%) or more of the shares of
stock entitled to vote for the election of directors, in the case of a
corporation, or fifty percent (50%) or more of the equity interests in the case
of any other type of legal entity, or status as a general partner in the case
of any partnership, or any other arrangement whereby a Party controls or has
the right to control the Board of Directors or equivalent governing body or
management of a corporation or other entity.

1.3.                              “Agreement” shall mean this
Agreement between the Parties, dated as of the Effective Date, including any
exhibits, schedules or other attachments hereto and incorporated herein, as any
of the foregoing may be validly amended from time to time.  In the event of any inconsistency between the
terms of this Agreement and the terms of any exhibits, schedules or other
attachments incorporated herein, the terms of this Agreement shall govern
unless the Parties expressly agree otherwise in writing.

1.4.                              “Allocable Overhead” shall mean
overhead costs incurred by IMMUNOGEN attributable to IMMUNOGEN’s supervisory
services, occupancy costs, and its payroll, information systems, human
relations, purchasing, accounts receivable or accounts payable functions which
are allocated to company departments based on space occupied or headcount or
another activity-based method, and shall include the “General Administrative
Fee” as defined hereinbelow.  For
purposes of any given calculation of “Allocable Overhead” hereunder, the “General
and Administrative Fee” shall equal [***] percent ([***]%) of the total amount
of Allocable Overhead (as calculated before the inclusion of any such
fee).  However, “Allocable Overhead”
shall not include any costs attributable to general corporate activities,
executive management, investor relations, corporate communications, business
development, legal affairs or finance.

Portions
of this Exhibit were omitted and have been filed separately with the Secretary
of the Commission pursuant to the Company’s application requesting confidential
treatment under Rule 24b-2 of the Securities Exchange Act of 1934.

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1.5.                                “Clinical Materials”
shall mean (a) supplies of ansamitocin P-3, and/or any other MAY Compound as
manufactured in accordance with all applicable GMPs and other legal
requirements and all applicable Specifications for such MAY Compound for use in
human clinical testing, and (b) supplies of any Licensed Product as
manufactured in accordance with all applicable GMPs and other legal
requirements and all applicable Specifications for such Licensed Product for
use in human clinical testing of any Licensed Product.

1.6.                              “Collaboration Committee” shall mean
the committee with representatives of each Party established as set forth in
Section 3.4.

1.7.                              “Combination Product” shall mean any Licensed Product
that contains, in addition to any conjugate of a [***] Antibody with any MAY
Compound, one or more other ingredients that has biologic activity as a
therapeutic agent when present alone.

1.8.                              “Confidential Information” shall have the meaning set
forth in Section 5.1.

1.9.                              “Control” or “Controlled”
shall mean, with respect to any Patent Rights or Technology (including, without
limitation, any MAY Compound, [***] Antibody or other proprietary biologic
material covered under this Agreement), the possession by a Party of the
ability to grant a license or sublicense of such patent rights, know-how or
other intellectual property and the rights thereto or to supply such compounds
or materials as provided for in this Agreement without violating the terms of
any arrangement or agreement between such Party and any Third Party.

1.10.                        “Development” and “Develop” shall mean, with respect
to any Licensed Product, all activities with respect to such Licensed Product
relating to research and development in connection with seeking, obtaining
and/or maintaining any Regulatory Approval for such Licensed Product in the
Field in the Territory, including without limitation, all pre-clinical research
and development activities, all human clinical studies, all activities relating
to developing the ability to manufacture any Licensed Product or any component
thereof (including, without limitation, process development work), and all
other activities relating to seeking, obtaining and/or maintaining any
Regulatory Approvals from the FDA and/or any Foreign Regulatory Authority.

1.11.                        “Drug Approval Application” shall
mean any application for Regulatory Approval (including pricing and
reimbursement approvals) required prior to any commercial sale or use of a
Licensed Product in any country or jurisdiction in the Territory, including,
without

Portions
of this Exhibit were omitted and have been filed separately with the Secretary
of the Commission pursuant to the Company’s application requesting confidential
treatment under Rule 24b-2 of the Securities Exchange Act of 1934.

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limitation, (a)
any NDA or MAA filed with the FDA or any Foreign Regulatory Authority, and (b)
any equivalent application filed with any Foreign Regulatory Authority for
Regulatory Approval (including pricing and reimbursement approvals) required
prior to any commercial sale or use of a Licensed Product in any country or
jurisdiction in the Territory.

1.12.                        “Effective Date” shall mean the date
first written above in the introductory paragraph to this Agreement.

1.13.                        “FDA” shall mean the United States
Food and Drug Administration and any successor agency or authority thereto.

1.14.                        “Field” shall mean any and all human
uses.

1.15.                        “First Commercial Sale” shall mean
the date of the first commercial sale (other than for purposes of obtaining
Regulatory Approval) of a Licensed Product by or on behalf of GENENTECH or any
Sublicensee.

1.16.                        “[***] Indication” shall mean the
[***] use permitted by the FDA or any Foreign Regulatory Authority in any
Regulatory Approval of a given Licensed Product.

1.17.                        “Foreign Regulatory Authority” shall
mean any applicable supranational, national, federal, state or local regulatory
agency, department, bureau or other governmental entity of any country or
jurisdiction in the Territory (other than the FDA in the United States), having
responsibility in such country or jurisdiction for any Regulatory Approvals of
any kind in such country or jurisdiction, and any successor agency or authority
thereto.

1.18.                        “Fully Burdened Manufacturing Cost”
shall mean, with respect to any Preclinical Materials or Clinical Materials
produced by IMMUNOGEN for GENENTECH under this Agreement, the sum of the
following components: (a) the costs of goods produced, as determined by
IMMUNOGEN in accordance with generally accepted accounting principles in the
United States, consistently applied, including, without limitation, direct
labor, material and product testing costs of such Preclinical Materials or
Clinical Materials; (b) any Third Party royalty costs directly allocable to the
manufacture or use of such Preclinical Materials or Clinical Materials; (c) all
Allocable Overhead on the cost of goods under clause (a) above; and (d) any
other costs borne by IMMUNOGEN, for the transport, customs clearance, duty,
insurance and/or storage of such Preclinical Materials or Clinical Materials.

1.19.                        “GENENTECH” shall mean Genentech,
Inc., a Delaware corporation, and its successors and permitted assigns under
this Agreement.

Portions
of this Exhibit were omitted and have been filed separately with the Secretary
of the Commission pursuant to the Company’s application requesting confidential
treatment under Rule 24b-2 of the Securities Exchange Act of 1934.

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1.20.                        “GLPs” shall mean all good
laboratory practices under Title 21 of the United States Code of Federal
Regulations, as amended from time to time.

1.21.                        “GMPs” shall mean all good
manufacturing practices under Title 21 of the United States Code of Federal
Regulations, as amended from time to time.

1.22.                        “Heads of Agreement” shall mean the
Heads of Agreement, dated May 2, 2000, as amended, whereunder the Parties
agreed upon the terms and conditions for a broader arrangement relating to the
conjugation of a larger array of antibodies and binding proteins to maytansine
derivatives such as DM1.

1.23.                        “HER2 License Agreement” shall mean
that certain License Agreement dated as of May 2, 2000, as amended May 3, 2006,
by and between the Parties with respect to the use of IMMUNOGEN’s proprietary
maytansinoid conjugation technology with GENENTECH’s Anti-HER2 antibodies and
other HER-2 binding proteins.

1.24.                        “IMMUNOGEN” shall mean ImmunoGen,
Inc., a Massachusetts corporation, and its successors and permitted assigns
under this Agreement.

1.25.                        “IMMUNOGEN Field” shall mean any and
all uses other  than any use that involves an antibody that binds
to an antigen that is subject to an exclusive license from IMMUNOGEN under, or
arising from, the Heads of Agreement or an antigen that is subject to an
Exclusive Target Option under the Heads of Agreement, during the period that
such exclusive license or Exclusive Target Option remains in effect.

1.26.                        “Improvement” shall mean: (a)
improvements to any MAY Compound, (b) improvements to methods of making
any MAY Compound, and (c) improvements to the conjugation process for
making antibody-drug conjugates that include any MAY Compound (including, for
example, reaction conditions or changes in process that create improvements in
the yield of such conjugate).  “Improvement”
excludes any and all of the following items (“GNE Exclusions”): (w) any
improvement that is specific to any antibody-drug conjugates that bind to an
antigen that is subject to an exclusive license from IMMUNOGEN under, or
arising from, the Heads of Agreement or is subject to an Exclusive Target
Option under the Heads of Agreement during the period that such exclusive
license or Exclusive Target Option remains in effect; (x) improvements to
[***] or [***], or the [***] of [***] or [***] of the foregoing;
(y) improvements arising out of GENENTECH [***] or [***] activities (whether
or not the associated [***] is the subject of a license or option to GENENTECH
by IMMUNOGEN); or

Portions
of this Exhibit were omitted and have been filed separately with the Secretary
of the Commission pursuant to the Company’s application requesting confidential
treatment under Rule 24b-2 of the Securities Exchange Act of 1934.

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(z) the [***]
or [***] of any [***] (i.e.,  the [***] or [***] of such [***] (e.g.,  the [***] of [***] or the [***] of [***] to [***]) and
[***] the manner of [***] such [***]) that binds to an antigen that is subject
to an exclusive license from IMMUNOGEN under, or arising from, the Heads of
Agreement or an antigen that is subject to an Exclusive Target Option under the
Heads of Agreement, during the period that such exclusive license or Exclusive
Target Option remains in effect.

1.27.                        “IND” shall mean an investigational
new drug application (as defined in Title 21 of the United States Code of
Federal Regulations, as amended from time to time) filed or to be filed with
the FDA with regard to any Licensed Product.

1.28.                        “Indemnitees” and “Indemnifying Party” shall have the
meanings set forth in Section 9.

1.29.                        “Licensed Patent Rights” shall mean
any and all Patent Rights in the Field in the Territory which are Controlled by
IMMUNOGEN as of the Effective Date or become Controlled by IMMUNOGEN during the
Term, to the extent that any of the foregoing is necessary or useful for the
Development, manufacture, use, import, export or sale of any Licensed Product
(or any component thereof) in the Field in the Territory.  The Licensed Patent Rights as of the
Effective Date include, without limitation, the patents and patent applications
set forth in the Existing License Agreement, as updated from time to time.

1.30.                        “Licensed Product” shall mean any
product containing any conjugate of a [***] Antibody with any MAY Compound, and
shall include, without limitation, any formulation thereof (including, without
limitation, any lyophilized, liquid, sustained release or aerosolized
formulation).  “Licensed Product” shall
also include any and all Combination Products (if any).

1.31.                        “Licensed Technology” shall mean any
and all Technology which relates to the use of any Licensed Product in the
Field in the Territory which is Controlled by IMMUNOGEN as of the Effective
Date or becomes Controlled by IMMUNOGEN during the Term, to the extent that any
of the foregoing relates to any Licensed Patent Rights or is necessary or
useful for the Development, manufacture, use, import, export or sale of any
Licensed Product in the Field in the Territory.

1.32.                        “MAA” shall mean an application
filed with the relevant Foreign Regulatory Authority in Europe seeking
Regulatory Approval to market and sell any Licensed Product in Europe or any
country or territory therein for a particular indication within the Field.

Portions
of this Exhibit were omitted and have been filed separately with the Secretary
of the Commission pursuant to the Company’s application requesting confidential
treatment under Rule 24b-2 of the Securities Exchange Act of 1934.

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1.33.                        “MAY Compound” shall mean any and
all maytansinoid compounds (including, without limitation, maytansine,
ansamitocin P-3 and DM1), whether produced by a botanical source, natural
fermentation or chemical synthesis, and shall include, without limitation, all
variants, fragments or derivatives of any of the foregoing, in each case owned
or otherwise Controlled by IMMUNOGEN. 
MAY shall include, without limitation, that certain maytansine
derivative known as “DM1” whose more specific chemical name is N2’-deacetyl-N2’-(3-mercapto-1-oxopropyl)-maytansine.

1.34.                        “NDA” shall mean a new drug
application (as defined in Title 21 of the United States Code of Federal
Regulations, as amended from time to time) filed with the FDA seeking
Regulatory Approval to market and sell any Licensed Product in the United
States for a particular indication within the Field.

1.35.                        “Net Sales”
shall mean, as to each calendar quarter during the Term, the gross invoiced
sales prices charged for all Licensed Products sold by GENENTECH or its
Sublicensees to Third Parties throughout the Territory during such calendar
quarter, less the following amounts incurred or paid by GENENTECH or its
Sublicensees during such calendar quarter with respect to sales of Licensed
Products regardless of the calendar quarter in which such sales were made:

(a)                                  trade,
cash and quantity discounts or rebates actually allowed or taken, including
discounts or rebates to governmental or managed care organizations;

(b)                                 credits
or allowances actually given or made for rejection of or return of, and for
uncollectible amounts on, previously sold Licensed Products or for retroactive
price reductions (including Medicare and similar types of rebates);

(c)                                  any
charges for insurance, freight, and other transportation costs directly related
to the delivery of Licensed Product to the extent included in the gross
invoiced sales price;

(d)                                 any
tax, tariff, duty or governmental charge levied on the sales, transfer,
transportation or delivery of a Licensed Product (including any tax such as a
value added or similar tax or government charge) borne by the seller thereof,
other than franchise or income tax of any kind whatsoever; and

(e)                                  any
import or export duties or their equivalent borne by the seller.  “Net Sales” shall not include sales or
transfers between GENENTECH and its Sublicensees, unless the

Portions of this Exhibit were omitted and have
been filed separately with the Secretary of the Commission pursuant to the
Company’s application requesting confidential treatment under Rule 24b-2 of the
Securities Exchange Act of 1934.

 7
 

Licensed
Product is consumed by the Sublicensee.

1.36.                        “Patent Rights” shall mean the
rights and interests in and to any and all issued patents and pending patent
applications (including inventor’s certificates and utility models) in any
country or jurisdiction in the Territory, including any and all provisionals,
non-provisionals, substitutions, continuations, continuations-in-part,
divisionals and other continuing applications, supplementary protection
certificates, renewals, and all letters patent on any of the foregoing, and any
and all reissues, reexaminations, extensions, confirmations, registrations and
patents of addition on any of the foregoing.

1.37.                        “Phase II Clinical Study” shall mean,
as to a particular Licensed Product for a particular indication, a controlled
and lawful study in humans of the safety, dose ranging and efficacy of such
Licensed Product for such indication, which is prospectively designed to
generate sufficient data (if successful) to commence a Phase III Clinical Trial
of such Licensed Product for such indication.

1.38.                        “Phase III Clinical Trial” shall mean, as to a
particular Licensed Product for a particular indication, a controlled and
lawful study in humans of the safety and efficacy of such Licensed Product for
such indication, which is prospectively designed to demonstrate statistically
whether such Licensed Product is safe and effective for use in such indication
in a manner sufficient to file an NDA to obtain Regulatory Approval to market
and sell that Licensed Product in the United States for the indication under
investigation in such study.

1.39.                        “Phase III Equivalent Decision” shall mean the date
(if any) on which GENENTECH (or its Sublicensee) decides, based on notification
and input from the FDA, that the data and results generated from the Phase II
Clinical Studies of a Licensed Product for a particular indication are
sufficient, without any Phase III Clinical Trial of such Licensed Product for
such indication, to support the filing of an NDA to obtain Regulatory Approval
to market and sell that Licensed Product in the United States for the
indication under investigation.

1.40.                        “Preclinical Materials” shall mean (a) supplies of
ansamitocin P-3, DM1 and/or any other MAY Compound as manufactured in
accordance with all applicable legal requirements and all applicable
Specifications for such MAY Compound for use in preclinical testing, and (b)
supplies of any Licensed Product as manufactured in accordance with all
applicable legal requirements and all applicable Specifications for such
Licensed Product for use in preclinical testing of any Licensed Product.

Portions
of this Exhibit were omitted and have been filed separately with the Secretary
of the Commission pursuant to the Company’s application requesting confidential
treatment under Rule 24b-2 of the Securities Exchange Act of 1934.

 8
 

1.41.                        “Regulatory Approval” shall mean any
and all approvals (including pricing and reimbursement approvals), product and
establishment licenses, registrations or authorizations of any kind of the FDA
or any Foreign Regulatory Authority necessary for the development, pre-clinical
and/or human clinical testing, manufacture, quality testing, supply, use,
storage, importation, export, transport, marketing and sale of a Licensed
Product (or any component thereof) for use in the Field in any country or other
jurisdiction in the Territory.  “Regulatory
Approval” shall include, without limitation, any NDA, MAA or other Drug
Approval Application.

1.42.                        “[***] Indication” shall mean the
[***] use permitted by the FDA or any Foreign Regulatory Authority in any
Regulatory Approval of a given Licensed Product and with respect to which
GENENTECH has made a [***] based on [***] that such indication will [***] at
least a $[***] in [***] in the [***].

1.43.                        “Specifications” shall mean any
specifications agreed upon in writing by the Parties relating to the
manufacturing and supply of any MAY Compound and/or Licensed Product hereunder.

1.44.                        “Sublicensee” shall have the meaning
set forth in Section 2.2, and “Material Sublicensee”
shall have the meaning set forth in Section 3.3.

1.45.                        “Technology” shall mean and include
any and all unpatented proprietary ideas, inventions, discoveries, Confidential
Information, biologic materials, data, results, formulae, designs,
specifications, methods, processes, formulations, techniques, ideas, know-how,
technical information (including, without limitation, structural and functional
information), process information, pre-clinical information, clinical
information, and any and all proprietary biological, chemical, pharmacological,
toxicological, pre-clinical, clinical, assay, control and manufacturing data
and materials.

1.46.                        “[***]” shall mean a protein that
corresponds to Swiss-Prot Primary accession number [***], or any variant or fragments thereof.

1.47.                        “[***] Antibody”
shall mean any monoclonal antibodies Controlled by GENENTECH that bind to [***]
and any other proteins binding to [***], and shall include, without limitation,
any variants (including, without limitation, humanized versions), fragments
(including, without limitation, single-chain versions) or derivatives of any of
the foregoing.

Portions
of this Exhibit were omitted and have been filed separately with the Secretary
of the Commission pursuant to the Company’s application requesting confidential
treatment under Rule 24b-2 of the Securities Exchange Act of 1934.

 9
 

1.48.                        “[***] Product” shall mean any
product containing an anti-[***] monoclonal antibody conjugated to a MAY
Compound.

1.49.                        “Term” shall mean the period
commencing on the Effective Date and continuing until the expiration or
termination of this Agreement in accordance with the terms hereof (including
Section 7).

1.50.                        “Territory” shall mean all countries
and jurisdictions of the world.

1.51.                        “[***] Indication” shall mean the
[***] use permitted by the FDA or any Foreign Regulatory Authority in any
Regulatory Approval of a given Licensed Product and with respect to which
GENENTECH has made a [***] based on [***] that such indication will [***] at
least $[***] in [***] in the [***].

1.52.                        “Third Party” shall mean any entity
other than GENENTECH, IMMUNOGEN and their respective Affiliates.

1.53.                        “Third Party Payments” shall have
the meaning set forth in Section 4.2.2.

1.54.                        “Valid Claim” shall mean a claim in
an issued, unexpired patent within the Licensed Patent Rights that (i) has not
been finally cancelled, withdrawn, abandoned or rejected by any administrative
agency or other body of competent jurisdiction, and (ii) has not been revoked,
held invalid, or declared unpatentable or unenforceable in a decision of a
court or other body of competent jurisdiction that is unappealable or
unappealed within the time allowed for appeal, and (iii) has not been rendered
unenforceable through disclaimer or otherwise, and (iv) is not lost through an
interference proceeding.

2.  GRANT OF
RIGHTS

2.1.                              License Grants.

(a)                                  License
to GENENTECH.  IMMUNOGEN hereby
grants to GENENTECH an exclusive (even as to IMMUNOGEN) royalty-bearing license
within the Territory, including the right to grant sublicenses as described in
Section 2.2 below, under the Licensed Patent Rights and Licensed Technology, to
Develop, have Developed, make, have made, use, have used, sell, have sold,
offer for sale, import, have imported, export and have exported Licensed
Products in the Field in the Territory, subject to the other terms and
conditions of this Agreement.

Portions
of this Exhibit were omitted and have been filed separately with the Secretary
of the Commission pursuant to the Company’s application requesting confidential
treatment under Rule 24b-2 of the Securities Exchange Act of 1934.

 10
 

(b)                                 License
to IMMUNOGEN.  GENENTECH hereby
grants to IMMUNOGEN a non-exclusive, royalty-free license (i) under
GENENTECH’s intellectual property interest in Improvements, to develop, make,
use, sell, offer for sale, import, and export any product that is not a
Licensed Product or a [***] Product, only within the IMMUNOGEN Field and
subject to Section 2.3(b) below and the remaining terms of this Section 2.1(b);
and (ii) also under GENENTECH’s intellectual property interest in Improvements,
to otherwise exploit Improvements for all uses within the IMMUNOGEN Field,
subject to Section 2.3(b) below and the remaining terms of this Section
2.1(b).  The foregoing license includes
the right to sublicense the rights granted under this Section 2.1(b) only if
all of the following three conditions (i), (ii) and (iii) are met:

 (i)                                  the sublicense is limited to the IMMUNOGEN Field;

 (ii)                               the sublicense is granted only in connection with
a license to IMMUNOGEN MAY Technology (where “IMMUNOGEN
MAY Technology” means Technology Controlled by IMMUNOGEN and
used in the conjugation of MAY Compounds to binding proteins), and the rights
granted for IMMUNOGEN MAY Technology are of the same scope (e.g., for the same product or technology and within the same
field and the same territory) as the rights granted for GENENTECH’s
Improvements; and

 (iii)                            GENENTECH obtains Substantially Similar Grant
Back Rights without incurring an obligation to pay any additional consideration
(either to IMMUNOGEN or to IMMUNOGEN’s sublicensee).  “Substantially Similar
Grant Back Rights” means non-exclusive rights in and to that
sublicensee’s “improvements” (improvements to MAY Compounds, methods of making
MAY Compounds, and methods of making antibody-drug conjugates) that are of
substantially the same scope (e.g., within
the same field and the same territory) as the rights granted in and to
Improvements under this Agreement. 
(GENENTECH may obtain such rights directly from IMMUNOGEN’s sublicensee
or indirectly through IMMUNOGEN; if GENENTECH obtains such rights from
IMMUNOGEN, IMMUNOGEN may have obtained such rights under license or by transfer
of ownership).

Nothing
in this Agreement or the course of dealings between the Parties or usage or
custom in the industry or trade shall be construed to confer any other rights
or licenses to any other intellectual property Controlled by either Party or
its Affiliates by implication, estoppel or

Portions
of this Exhibit were omitted and have been filed separately with the Secretary
of the Commission pursuant to the Company’s application requesting confidential
treatment under Rule 24b-2 of the Securities Exchange Act of 1934.

 11
 

otherwise.  GENENTECH has no obligation to [***] in any
[***] or [***] of [***] to [***] or a [***] of [***] with respect to [***].

2.2                                 Sublicenses.  GENENTECH
shall have the right freely to grant sublicenses to all or any portion of its
rights under the license rights granted pursuant to Section 2.1(a) hereof to
any Affiliate or Third Party (in any case, a “Sublicensee”);
provided, however, that (a) each such sublicense shall be
consistent with the terms and conditions of this Agreement, and (b) GENENTECH
shall remain obligated to ensure payment of all of its milestone and royalty
obligations as set forth in Section 4 hereof.

2.3                                 IMMUNOGEN Retained Rights and Covenants; GENENTECH
Technology or Patent Rights.

(a)                                  Retained
Rights.  Subject to the other terms
of this Agreement, including, without limitation, Section 2.3(b) hereof,
IMMUNOGEN retains the right to use the Licensed Technology and practice the
Licensed Patent Rights (i) to perform its work under Sections 3.3, 3.4, 3.5 and
3.6 hereof relating to the Collaboration Committee and to manufacture and
supply Preclinical Materials and Clinical Materials for GENENTECH (and its
Sublicensees), and (ii) to develop, have developed, make, have made, use,
have used, sell have sold, offer for sale, import, have imported, export and
have exported any product that is not a Licensed Product or a [***] Product,
subject to Section 2.3(b) below.

(b)                                 Covenants.  It is hereby further agreed that (i) during
the Term of this Agreement, IMMUNOGEN shall not Develop, have Developed, make,
have made, use, have used, sell, have sold, offer for sale, import, have
imported, export and have exported any [***] Product, which restriction shall
be [***] for [***] of this Agreement if, during a [***] prior to expiration or
termination of this Agreement, [***] is [***] or [***] with a [***], if [***]
is subject to a [***] of [***], or if this Agreement is [***] pursuant to
[***], and (ii) during the Term of this Agreement, and for [***] (which [***]
shall not apply in connection with expiration of this Agreement under [***]
below or in connection with [***] of this Agreement by [***] under Section
7.2(a) below, but which shall apply in connection with any other [***] of this
Agreement, including by [***] under [***] below), IMMUNOGEN shall not grant to
any Third Party any license or other right under any Patent Rights or
Technology owned or Controlled by

Portions
of this Exhibit were omitted and have been filed separately with the Secretary
of the Commission pursuant to the Company’s application requesting confidential
treatment under Rule 24b-2 of the Securities Exchange Act of 1934.

 12
 

IMMUNOGEN to Develop,
have Developed, make, have made, use, have used, sell, have sold, offer for
sale, import, have imported, export and have exported, any [***] Product.

(c)                                  No
Rights to GENENTECH Technology or Patent Rights.  Except
for the license granted to IMMUNOGEN by GENENTECH in Section 2.1(b) above,
nothing in this Section 2.3 or any other provision of this Agreement shall be
construed as a grant to IMMUNOGEN of any license or other rights with respect
to any Technology (including, without limitation, any Confidential Information)
or Patent Rights owned or Controlled (in whole or in part) by GENENTECH.

3.  DEVELOPMENT AND
COMMERCIALIZATION

OF LICENSED PRODUCTS.

3.1                                 Development and Commercialization.

(a)                                  Responsibility.  On and after the Effective Date,
except as otherwise agreed in writing with respect to certain process
development and manufacturing activities, GENENTECH shall have full control and
authority over, and sole responsibility for, all Development and
commercialization of Licensed Products in the Field in the Territory,
including, without limitation, (i) all pre-clinical Development activities
(including any pharmaceutical development work on formulations or process
development relating to any Licensed Product), (ii) all activities related to
human clinical trials (including any phase I clinical studies, any Phase II
Clinical Studies or any Phase III Clinical Trials), (iii) all activities
relating to manufacture and supply of [***] Antibodies, all MAY Compounds
(including ansamitocin P-3 and DM1) and all Licensed Products, solely to the
extent such activities relate to the development and commercialization of
Licensed Products (including all required process development and scale up work
with respect thereto), (iv) all marketing, promotion, sales, distribution,
import and export activities relating to any Licensed Product (including any
post-marketing trials or databases and post-marketing safety surveillance), and
(v) all activities relating to any regulatory filings, registrations,
applications and Regulatory Approvals relating to any of the foregoing
(including any INDs or foreign equivalents, any manufacturing facility
validation and/or licensure, any Drug Approval Applications and any other
Regulatory Approvals).  Except as
described in the next sentence, GENENTECH shall own all data, results

Portions of this Exhibit were omitted and have
been filed separately with the Secretary of the Commission pursuant to the
Company’s application requesting confidential treatment under Rule 24b-2 of the
Securities Exchange Act of 1934.

 13
 

and all other information arising from any such
activities under this Agreement, including, without limitation, all regulatory
filings, registrations, applications and Regulatory Approvals relating to
Licensed Products (including any INDs or foreign equivalents, any Drug Approval
Applications and any other Regulatory Approvals), and all of the foregoing
information, documentation and materials shall be considered Confidential
Information and Technology solely owned by GENENTECH.  IMMUNOGEN shall own all data, results and all
other information arising from IMMUNOGEN’s activities relating to the
manufacture and supply of MAY Compounds (including ansamitocin P-3 and DM1) to
GENENTECH, and all of the foregoing information, documentation and materials
shall be considered Confidential Information and Technology solely owned by
IMMUNOGEN.  All activities relating to
Development and commercialization under this Agreement shall be undertaken at
GENENTECH’s sole cost and expense, except as otherwise expressly provided in
this Agreement.

(b)                                 Due Diligence.  GENENTECH will exercise its
commercially reasonable efforts and diligence in Developing and commercializing
Licensed Products in accordance with its business, legal, medical and
scientific judgment, and in undertaking investigations and actions required to
obtain appropriate Regulatory Approvals necessary to market Licensed Products
in the Field in the Territory, such reasonable efforts and diligence to be in
accordance with the efforts and resources GENENTECH would use for a compound
owned by it or to which it has rights, which is of similar market potential at
a similar stage in development as the applicable Licensed Product, taking into
account the competitiveness of the marketplace, the proprietary position of the
Licensed Product, the relative potential safety and efficacy of the Licensed
Product, the regulatory requirements involved in its Development,
commercialization and Regulatory Approval,  the cost of goods and availability of capacity to
manufacture and supply the Licensed Product at commercial scale, the
profitability of the applicable Licensed Product, and other relevant factors
including, without limitation, technical, legal, scientific or medical
factors.  In the event that GENENTECH
fails to use due diligence as required hereunder, then on a Licensed
Product-by-Licensed Product and country-by-country basis as to the Licensed
Product in the country in which GENENTECH has failed to use due diligence as
required hereunder, IMMUNOGEN’s exclusive remedy shall be, in its sole
discretion (i) to terminate the licenses granted under Section 2.1 this
Agreement for breach under Section 7.2(a) below

Portions
of this Exhibit were omitted and have been filed separately with the Secretary
of the Commission pursuant to the Company’s application requesting confidential
treatment under Rule 24b-2 of the Securities Exchange Act of 1934.

 14
 

(including the notice and cure provisions therein) or (ii) to convert the
licenses granted under Section 2.1 of this Agreement from exclusive licenses to
non-exclusive licenses, in either case only as such licenses apply to such
Licensed Product in such country, which termination or conversion, as the case
may be, shall be effective upon expiration of the cure period specified in
7.2(a) below provided that such failure remains uncured upon such expiration.

3.2                                 Updates and Reports; Exchanges of Adverse Event Information.

(a)                                  Updates and Reports. 
GENENTECH shall keep IMMUNOGEN informed of the progress of GENENTECH’s
efforts to Develop and commercialize Licensed Products in the Field in the
Territory as provided in this Section 3.2(a). 
GENENTECH (or its Sublicensee) shall provide IMMUNOGEN with brief
written reports as provided herein no less frequently than on each anniversary
of the Effective Date during the Term (commencing with the first anniversary of
the Effective Date).  Such reports shall
summarize GENENTECH’s material efforts to Develop and commercialize all
Licensed Products hereunder, identify the Drug Approval Applications with
respect to any Licensed Product that GENENTECH and its Sublicensees have filed,
sought or obtained in the prior twelve (12)-month period, and any they
reasonably expect to make, seek or attempt to obtain in the following twelve
(12)-month period.  In addition,
GENENTECH (or its Sublicensee) shall provide IMMUNOGEN with prompt written notice
of the occurrence of any event giving rise to an obligation to make a milestone
payment to IMMUNOGEN under Section 4.1, and shall provide IMMUNOGEN with prompt
written notice of the occurrence of the First Commercial Sale of any particular
Licensed Product. All such reports and notices shall be sent to the attention
of IMMUNOGEN’s designated representative, who shall be its Chief Executive
Officer unless IMMUNOGEN otherwise notifies GENENTECH.

(b)                                 Adverse Events.  In addition to such reports,
GENENTECH agrees to provide IMMUNOGEN with Adverse Event information and
product complaint information relating to Licensed Products (but not relating
to any other products of GENENTECH, including any antibody that may be included
in a Licensed Product, to the extent that antibody is used in its “naked” form
or in connection with a different effector molecule) as compiled and prepared
by GENENTECH in the normal course of business in connection with the
Development, commercialization or sale of any Licensed Product, within time
frames consistent with reporting obligations under applicable laws and
regulations.  To the extent it could
reasonably apply or

Portions
of this Exhibit were omitted and have been filed separately with the Secretary
of the Commission pursuant to the Company’s application requesting confidential
treatment under Rule 24b-2 of the Securities Exchange Act of 1934.

 15
 

could reasonably be relevant to a Licensed Product, IMMUNOGEN agrees to
provide GENENTECH with Adverse Event and product complaint information relating
to any product containing any MAY Compound that is compiled and prepared by
IMMUNOGEN or any Third Party in the normal course of business in connection
with the development, commercialization or sale of any such product, within
time frames consistent with reporting obligations under applicable laws and
regulations; provided, however, that the foregoing shall not
require IMMUNOGEN to violate any agreements with or confidentiality obligations
owed to any Third Party.  GENENTECH shall
provide its Adverse Event and product complaint information hereunder to
IMMUNOGEN’s designated representative, who shall be its Chief Regulatory
Officer unless IMMUNOGEN otherwise notifies GENENTECH. IMMUNOGEN shall provide
its Adverse Event and product complaint information hereunder to GENENTECH’s
designated representative, who shall be the head of its Drug Safety group in
GENENTECH’S Medical Affairs Department unless GENENTECH otherwise notifies
IMMUNOGEN.

(c)                                  Confidential Information.  All
reports, updates, Adverse Event, product complaint and other information
provided by one Party to the other Party under this Agreement (including under
this Section 3), shall be considered Confidential Information of the disclosing
Party, subject to the terms of Section 5.

3.3                                 Reasonable Assistance by IMMUNOGEN.  In
connection with the exclusive grant of rights to GENENTECH under Section 2.1
above, and subject to the other terms of this Agreement, IMMUNOGEN shall
provide GENENTECH (and any Sublicensee of GENENTECH with respect to all of
GENENTECH’s license rights hereunder to make or have made all Licensed Products
or any particular Licensed Product(s) throughout the Territory or in a
particular geographic region of the Territory, and/or all of GENENTECH’s
license rights hereunder to Develop or commercialize all Licensed Products or
any particular Licensed Product(s) throughout the Territory  or in a particular geographic region of the
Territory (in any case, a “Material Sublicensee”))
such information and materials comprising the Licensed Technology and/or
Licensed Patent Rights as GENENTECH (or its Material Sublicensee) may
reasonably request.  Without limiting the
generality of the foregoing, IMMUNOGEN shall provide all of such technical
assistance within IMMUNOGEN’s area of expertise (or its subcontractors)
concerning the Development and commercialization of Licensed Products as

Portions
of this Exhibit were omitted and have been filed separately with the Secretary
of the Commission pursuant to the Company’s application requesting confidential
treatment under Rule 24b-2 of the Securities Exchange Act of 1934.

 16
 

may be reasonably requested by GENENTECH (or its Material Sublicensee)
from time to time during the Term, provided that such technical assistance and
expertise is within the scope of the Licensed Technology and/or Licensed Patent
Rights covered under this Agreement. 
Such technical assistance and expertise shall include, but not be
limited to, visits by IMMUNOGEN personnel to GENENTECH and visits by GENENTECH
to IMMUNOGEN (or its subcontractors), at GENENTECH’s expense, at such times and
for such periods of time as may be reasonably acceptable to the Parties.   Without limiting the generality of the
foregoing, within [***] ([***]) days after GENENTECH’s reasonable written
request, IMMUNOGEN shall deliver to GENENTECH a list or description of the
documents and information that embody the Licensed Technology.  GENENTECH 
will inform IMMUNOGEN which of those identified documents and information
GENENTECH believes are reasonably related to its exercise of the license rights
under this Agreement and, within [***] ([***]) days after that identification,
IMMUNOGEN shall deliver to GENENTECH a copy of those documents and other
information.

3.4                                 Collaboration Committee.

(a)                                  Mandate of Committee.  Promptly
after the Effective Date, the Parties shall form a “Collaboration Committee” to serve as a forum for
coordination and communication between the Parties with respect to activities
related to Licensed Products for which the Parties agree there is a need for
coordination and communication (including, without limitation, all process
science and process development work, formulation work, and quality control/
assurance work hereunder), and to assist GENENTECH in its exercise of its
rights to make or have made Licensed Products under this Agreement.  Within [***] ([***]) days after the Effective
Date, the Parties shall each nominate an equal number of representatives (which
shall be no less than two (2) each) for membership on the Collaboration
Committee.  Each Party may change its representative(s)
as it deems appropriate by notice to the other Party.  The input of the IMMUNOGEN representatives on
the Collaboration Committee shall be fully considered by the Collaboration
Committee; provided, however, that all decisions of the Collaboration
Committee shall be subject to final approval by GENENTECH.

(b)                                 Chair of Committee; Meetings.  The
Parties hereby agree that (i) the chair of the Collaboration Committee shall be
one of the GENENTECH representatives on the Collaboration Committee, as
designated by GENENTECH; provided, however, that [***] the [***]
after the Effective Date, the Collaboration Committee shall be [***] by a [***]
on the

Portions of this Exhibit were omitted and have
been filed separately with the Secretary of the Commission pursuant to the
Company’s application requesting confidential treatment under Rule 24b-2 of the
Securities Exchange Act of 1934.

 17
 

Collaboration Committee (as designated by [***]) and an [***] on the
Collaboration Committee (as designated by [***]); (ii) all decisions of the
Collaboration Committee shall be subject to the approval of the GENENTECH chair
(including [***] the [***] there is a [***]); (iii) the Collaboration Committee
shall meet on a semi-annual basis or other schedule agreed upon by the Parties,
unless at least thirty (30) days in advance of any meeting the chair (or
co-chairs during the first twelve (12) months) of the Collaboration Committee
determine that there is no need for a meeting (in which instance, the next
Collaboration Committee meeting shall also be scheduled as agreed upon by the
Parties); (iv) the location of meetings of the Collaboration Committee shall
alternate between IMMUNOGEN’s offices in Massachusetts and GENENTECH’s offices
in California, unless otherwise agreed by the Parties and, as agreed upon by
the Parties, Collaboration Committee meetings may be face-to-face or may be
conducted through teleconferences and/or videoconferences.  In addition to its Collaboration Committee
representatives, each Party shall be entitled to have other employees attend
such meetings to present and participate, though not in a decision-making
capacity.  Each Party shall bear all
costs and expenses, including travel and lodging expense, that may be incurred
by its Collaboration Committee representatives or other of its attendees at
Collaboration Committee meetings, as a result of such meetings hereunder.  Minutes of each Collaboration Committee
meeting will be transcribed and issued to members of the Collaboration
Committee by the chair (or the GENENTECH co-chair, as the case may be) within
thirty (30) days after each meeting, and such minutes shall be reviewed and
modified as mutually required to obtain approval of such minutes promptly
thereafter.

3.5                                 Supply of Preclinical Materials.  During the Term of this Agreement, IMMUNOGEN
shall supply to GENENTECH (or its Material Sublicensee) with such quantities of
Preclinical Materials as may be reasonably requested by GENENTECH (or its
Material Sublicensee) in order to conduct all pre-clinical Development
activities relating to Licensed Products. 
GENENTECH (or its Material Sublicensee) shall order all amounts of
Preclinical Materials, and IMMUNOGEN shall deliver all such ordered amounts, in
accordance with advance ordering timeframes and delivery timeframes to be
agreed upon by the Parties through the Collaboration Committee.  IMMUNOGEN shall use its commercially
reasonable efforts to deliver such amounts of Preclinical Materials ordered in
accordance with the foregoing (including such agreed upon timeframes) in a
timely manner.  In connection with any
ordering of

Portions
of this Exhibit were omitted and have been filed separately with the Secretary
of the Commission pursuant to the Company’s application requesting confidential
treatment under Rule 24b-2 of the Securities Exchange Act of 1934.

 18
 

Preclinical
Materials by GENENTECH (or its Material Sublicensee), IMMUNOGEN shall provide
GENENTECH (or its Material Sublicensee) promptly with IMMUNOGEN’s good faith
estimate of the Fully Burdened Manufacturing Cost for manufacture and supply of
such Preclinical Materials.  IMMUNOGEN’s
price to supply Preclinical Materials to GENENTECH (or its Material
Sublicensee) shall equal [***]% of IMMUNOGEN’s Fully Burdened Manufacturing
Cost for such Preclinical Materials as approved by GENENTECH (or its Material
Sublicensee).  Nothing herein shall
preclude GENENTECH from making its own arrangements for manufacture and supply
of Preclinical Materials on its own or with Third Parties, in exercise of its
license rights under Section 2.1. 
GENENTECH hereby agrees that (a) it shall not use the Preclinical
Materials in any human subject, (b) it shall use the Preclinical Materials in
compliance with all applicable federal, state and local laws and regulations,
and (c) it (as a matter of contract between itself and IMMUNOGEN) shall assume
all liability for damages that may arise from the use, storage and disposal of
any Preclinical Materials to the extent provided pursuant to Section 9
below.  GENENTECH shall be entitled to
transfer Preclinical Materials to any Third Party under terms obligating such
Third Party not to transfer or use such Preclinical Materials except in
compliance with the foregoing clauses (a) and (b) of this Section 3.5.

3.6                                 Supply of Clinical Materials.  During the Term of this Agreement, IMMUNOGEN
shall supply to GENENTECH (or its Material Sublicensee) with such quantities of
Clinical Materials as may be reasonably requested by GENENTECH (or its Material
Sublicensee) in order to conduct all human clinical trials of Licensed Products
through non-pivotal Phase II Clinical Studies. 
To the extent GENENTECH requests IMMUNOGEN to manufacture Clinical
Materials as provided in the foregoing sentence, IMMUNOGEN and GENENTECH shall
enter into separate supply and quality agreements detailing the terms of supply
for any Clinical Materials that IMMUNOGEN is so requested to supply to
GENENTECH for the purpose of conducting clinical trials.  GENENTECH (or its Material Sublicensee) shall
order all amounts of Clinical Materials, and IMMUNOGEN shall deliver all such
ordered amounts, in accordance with forecasting parameters, advance ordering
timeframes and delivery timeframes to be agreed upon by the Parties through the
Collaboration Committee.  IMMUNOGEN shall
use its commercially reasonable efforts to deliver such amounts of Clinical
Materials ordered in accordance with the foregoing (including such agreed upon
timeframes) in a timely manner.  In
connection with any ordering of Clinical Materials by GENENTECH (or its

Portions
of this Exhibit were omitted and have been filed separately with the Secretary
of the Commission pursuant to the Company’s application requesting confidential
treatment under Rule 24b-2 of the Securities Exchange Act of 1934.

 19
 

Material
Sublicensee), IMMUNOGEN shall provide GENENTECH (or its Material Sublicensee)
promptly with IMMUNOGEN’s good faith estimate of the Fully Burdened
Manufacturing Cost for manufacture and supply of such Clinical Materials.  IMMUNOGEN’s price to supply Clinical
Materials to GENENTECH (or its Material Sublicensee) shall equal [***]% of
IMMUNOGEN’S Fully Burdened Manufacturing Cost for such Clinical Materials as
approved by GENENTECH (or its Material Sublicensee).  Nothing herein shall preclude GENENTECH from
making its own arrangements for manufacture and supply of Clinical Materials on
its own or with Third Parties, in exercise of its license rights under Section
2.1. GENENTECH hereby agrees that (a) it shall use the Clinical Materials in
compliance with all applicable federal, state and local laws, and (b) it (as a
matter of contract between itself and IMMUNOGEN) shall [***] all [***] for
[***] that may arise from the [***] and [***] of such Clinical Materials to the
extent provided pursuant to Section 9 below. GENENTECH shall be entitled to
transfer Clinical Materials to any Third Party under terms obligating such
Third Party not to transfer or use such Clinical Materials except in compliance
with the foregoing clause (a) of this Section 3.6.

3.7                                 Purchase of Equipment.  If, during the Term of this Agreement,
IMMUNOGEN determines in good faith that it is necessary or advisable to
purchase equipment or instruments in order to perform any of its obligations to
manufacture Preclinical Materials and Clinical Materials under Sections 3.5 or 3.6
of this Agreement, then IMMUNOGEN shall provide the Collaboration Committee
with written notice of such determination, along with the estimated price for
such purchase and quality parameters for the equipment or instruments, for the
Collaboration Committee’s approval of such price and features.  Promptly after the consummation of such
purchase, assuming that the Collaboration Committee has provided its approval
hereunder, IMMUNOGEN shall provide GENENTECH with a copy of the invoice or
invoices reflecting such purchase, and GENENTECH shall reimburse IMMUNOGEN for
the purchase of all such approved equipment hereunder within [***] days of its
receipt of such invoice from IMMUNOGEN; provided, however, that
no costs reimbursed by GENENTECH hereunder (or depreciation of such purchased
equipment or instruments) shall be includible or included within the
calculation of any Fully Burdened Manufacturing Costs under this Agreement.

Portions
of this Exhibit were omitted and have been filed separately with the Secretary
of the Commission pursuant to the Company’s application requesting confidential
treatment under Rule 24b-2 of the Securities Exchange Act of 1934.

 20
 

4.  PAYMENTS
AND ROYALTIES

4.1                                 Milestone Payments for Licensed Products.

4.1.1                        Milestones.  In consideration of the grant of the license
by IMMUNOGEN hereunder, and subject to the other terms of this Agreement,
GENENTECH will make the following nonrefundable, noncreditable (except as
expressly provided in Section 4.1.2 below) payments to IMMUNOGEN, on the payment
terms in Section 4.5:

	
  [***] Milestones

  	
   

  	
  Milestone Payment

  	
   

  
	
   

  	
   

  	
   

  	
   

  
	
  Effective Date

  	
   

  	
  $

  	
  1 Million

  	
   

  
	
   

  	
   

  	
   

  	
   

  
	
  [***] for a [***]

  	
   

  	
  $

  	
  [***]

  	
   

  
	
   

  	
   

  	
   

  	
   

  
	
  [***] of [***] in [***] for
  a [***]

  	
   

  	
  $

  	
  [***]

  	
   

  
	
   

  	
   

  	
   

  	
   

  
	
  [***] of [***] of [***] in
  [***] for a [***] or [***]

  	
   

  	
   

  	
   

  
	
  [***] for a [***]

  	
   

  	
  $

  	
  [***]

  	
   

  
	
   

  	
   

  	
   

  	
   

  
	
  [***] of [***] by the [***]

  	
   

  	
   

  	
   

  
	
  for a [***] for [***]

  	
   

  	
  $

  	
  [***]

  	
   

  
	
   

  	
   

  	
   

  	
   

  
	
            [***]
  of an [***] or other [***] in the [***] for a

  	
   

  	
   

  	
   

  
	
  [***] for [***]

  	
   

  	
  $

  	
  [***]

  	
   

  
	
   

  	
   

  	
   

  	
   

  
	
  [***] of a [***] for a

  	
   

  	
   

  	
   

  
	
  [***] in [***] for [***]

  	
   

  	
  $

  	
  [***]

  	
   

  
	
   

  	
   

  	
   

  	
   

  
	
  [***] of [***] by the [***]
  for a [***] for [***]

  	
   

  	
  $

  	
  [***]

  	
   

  
	
   

  	
   

  	
   

  	
   

  
	
  [***] of [***] by the [***]
  for a [***] for a [***]

  	
   

  	
  $

  	
  [***]

  	
   

  

 

	
  [***] Milestones

  	
   

  	
  Milestone Payment

  	
   

  
	
   

  	
   

  	
   

  	
   

  
	
  [***] of [***]
  greater than $[***]

  	
   

  	
  $

  	
  [***]

  	
   

  
	
   

  	
   

  	
   

  	
   

  
	
  [***] of [***] greater
  than $[***]

  	
   

  	
  $

  	
  [***]

  	
   

  

 

It is hereby
acknowledged and agreed that any milestone payment shall be made only once,
with respect to the first achievement of the relevant milestone for the first
Licensed Product, regardless of how many times such milestones are achieved by
Licensed Products and regardless of how many times a particular Licensed
Product achieves such milestones.

Portions
of this Exhibit were omitted and have been filed separately with the Secretary
of the Commission pursuant to the Company’s application requesting confidential
treatment under Rule 24b-2 of the Securities Exchange Act of 1934.

 21

GENENTECH shall notify
IMMUNOGEN of the achievement of milestones hereunder as provided in Section
3.2(a) above.

4.1.2                        [***] of [***].  GENENTECH shall be [***] to [***] its [***]
(but not any [***]) [***] to IMMUNOGEN only to the extent set forth in this Section
4.1.2.  As to the Licensed Product with
respect to which [***] are owed to IMMUNOGEN under this Section 4.1, GENENTECH
shall be [***] to [***] [***] percent ([***]%) of each such [***] made with
respect to such Licensed Product hereunder [***][***][***] to IMMUNOGEN
hereunder with respect to such Licensed Product, but (a) only if prior to the
date of such [***][***], GENENTECH (or its Sublicensee) has modified such
Licensed Product such that it would not (even in the absence of the license
under this Agreement) [***] a [***] within the Licensed Patent Rights in the
United States (excluding any Patent Rights [***] by [***] and [***]), and (b)
only if such modification was undertaken (i) to address a [***] or [***] with
respect to such Licensed Product or its Development, manufacture, use or sale,
(ii) to obtain a [***] in the toxicity, safety or efficacy profile of such
Licensed Product, or (iii) to obtain a [***] in the ability to make or have
made such Licensed Product (or any component thereof).

4.2                                 Payment of Royalties; Royalty Rates; Accounting
for Royalties and Records.

4.2.1                        Royalty Payments.  In consideration of the grant of the license
by IMMUNOGEN hereunder, and subject to the other terms of this Agreement
(including the remainder of this Section 4), commencing on the first date of
First Commercial Sale of Licensed Products in such country or jurisdiction in
the Territory, GENENTECH shall pay to IMMUNOGEN the following royalties based
on total Net Sales of all Licensed Products sold by GENENTECH and/or its
Sublicensees, on an incremental basis in each calendar year during the Term, at
the following rates in [***] of the [***]:

	
  For Net Sales of a Licensed Product

  [***] in any Calendar Year

  During the Term:

  	
   

  	
  Royalty Rate (% of Net Sales)

  	
   

  	
   

  
	
   

  	
   

  	
   

  	
   

  	
   

  
	
  Above $[***] and up to
  $[***]

  	
   

  	
  [***]

  	
  %

  	
   

  
	
   

  	
   

  	
   

  	
   

  	
   

  
	
  Above $[***]

  	
   

  	
  [***]

  	
  %

  	
   

  

 

Portions of this Exhibit were
omitted and have been filed separately with the Secretary of the Commission
pursuant to the Company’s application requesting confidential treatment under Rule
24b-2 of the Securities Exchange Act of 1934.

 22
 

 

	
  For Net Sales of a Licensed Product

  [***] in any Calendar Year

  During the Term:

  	
   

  	
  Royalty Rate (% of Net Sales)

  	
   

  	
   

  
	
   

  	
   

  	
   

  	
   

  	
   

  	 

	
  Above $[***] and
  up to $[***]

  	
   

  	
  [***]

  	
  %

  	
   

  	 

	
   

  	
   

  	
   

  	
   

  	
   

  	 

	
  Above $[***]

  	
   

  	
  [***]

  	
  %

  	
   

  	 

								

 

By way of example
only, if during the Term a Licensed Product achieved total Net Sales in a given
calendar of $[***], the applicable royalty rate would be [***]% of Net Sales
for Net Sales up to $[***], and [***]% of Net Sales for Net Sales over $[***].

4.2.2                        Third Party Royalty Offset.  Subject to the other
terms of this Agreement, on a country-by-country basis, the royalties otherwise
due and payable by GENENTECH under Section 4.2.1 above (but not the royalties
otherwise due and payable by GENENTECH under Section 4.2.3(a) or (b) below)
shall be reduced as provided in this Section 4.2.2:

(a)                                  GENENTECH
Process Development.  Consistent with
GENENTECH’S due diligence obligations under this Agreement, GENENTECH agrees to
exercise due diligence to attempt to Develop a commercially viable
manufacturing process relating to the manufacture and supply of Licensed
Products.  For purposes of this
Agreement, GENENTECH shall determine in good faith the commercial viability of
any such manufacturing process that is Developed hereunder, taking into
account, without limitation, the following factors relevant thereto:  the consistency and reproducibility of the
process itself; the consistency, reproducibility, safety and efficacy of the
resulting conjugated Licensed Products; any regulatory issues; the availability
of capacity; the cost of goods and other components of Fully Burdened
Manufacturing Cost as applied to such process and to the overall manufacture
and supply of Licensed Products; the overall profitability of the Licensed Products;
and the ability to produce at commercial scale quantities.

(b)                                 Partial
Offset.  If GENENTECH is not able to
Develop such a commercially viable manufacturing process after exercising due
diligence as required hereunder, GENENTECH may elect to license a manufacturing
process from a Third Party, and in that event GENENTECH shall be entitled to
offset up to [***] percent ([***]%) of any Third Party Payments it makes in
connection with any license providing rights to any such manufacturing

Portions
of this Exhibit were omitted and have been filed separately with the Secretary
of the Commission pursuant to the Company’s application requesting confidential
treatment under Rule 24b-2 of the Securities Exchange Act of 1934.

 23
 

process against
the royalties due to IMMUNOGEN pursuant to Section 4.2.1 above, subject to the
clause (d) of this Section 4.2.2. 
GENENTECH shall not be entitled to the offset under this clause (b) if
it fails to exercise due diligence as required hereunder.

(c)                                  Full
Offset.  If GENENTECH determines in
good faith that it is necessary, in order to exploit the license granted to it
under Section 2.1 of this Agreement in any country, to make royalty payments to
any Third Party (“Third Party Payments”)
under any license agreement that GENENTECH determines, in good faith, is
necessary in connection with the Development, manufacture, use or sale of any
MAY Compound, the linker of any MAY Compound to a [***] Antibody, and/or the
conjugation of a [***] Antibody to any MAY Compound (including, without limitation,
DM1) as part of any Licensed Product, then in any such case the royalties due
to IMMUNOGEN pursuant to Section 4.2.1 above for such Licensed Product shall be
reduced by [***] of such Third Party Payments, subject to the limitations set
forth in clause (d) of this Section 4.2.2. 
If GENENTECH elects to take any such license agreement as described
herein without having first determined that it is necessary (as determined by
GENENTECH in good faith) in order to exploit the license granted to it under
Section 2.1 of this Agreement in any country, then GENENTECH shall not be
entitled to the offset under this clause (c). If IMMUNOGEN in good faith
disputes GENENTECH’s determination hereunder, the Parties shall submit the
matter promptly to IMMUNOGEN’S Chief Executive Officer and a designated officer
of GENENTECH with settlement authority.

(d)                                 Limitations
on Offsets.  The royalty offset in
Section 4.2.2(c) above is separate and cumulative to the royalty offset under
Section 4.2.2(b) above, but each is subject to the limitations set forth in
this Section 4.2.2(d) as follows.  No
royalty reductions under this Section 4.2.2, alone or in the aggregate, shall
reduce the royalty (if any) for any Licensed Product in any country payable
pursuant to Section 4.2.1 above  by more than
[***] percent ([***]%) of the royalties otherwise owed to IMMUNOGEN thereunder,
nor reduce such royalty for such Licensed Product in any such country to less
than [***] percent ([***]%) of Net Sales of such Licensed Product in such country.

4.2.3                        [***] and [***].

(a)
                                  Notwithstanding
anything set forth in [***] above, the [***] set forth therein shall apply, on
a [***] and [***] basis, to [***] of [***] or its [***], [***] or [***] in
[***] would, [***] for the [***] under this Agreement, [***] a [***] the [***]
(excluding any

Portions
of this Exhibit were omitted and have been filed separately with the Secretary
of the Commission pursuant to the Company’s application requesting confidential
treatment under Rule 24b-2 of the Securities Exchange Act of 1934.

 24
 

[***] by [***] and
[***]).  Subject to the other terms of
this Agreement (except for Section 4.2.2 above, which shall not apply), on a
[***] and [***] where and as of when the [***] under Section 4.2.1 [***] as a
[***] of this Section 4.2.3, GENENTECH shall [***] to IMMUNOGEN a [***] to
[***][***] ([***]%) of [***] of [***] by [***] and/or its [***] in [***].

(b)                                    [***].  Notwithstanding anything set forth in [***]
above, the [***] set forth in [***] above shall no longer apply, on a [***]
basis, on and after the [***] on which any [***] to [***] and [***] in a [***]
any [***].  Subject to the other terms of
this Agreement (except for [***], which shall not apply), on a [***] basis
where the [***] under [***] do not apply as a result of this [***],  [***] on the [***] of such [***] of [***] in
such [***], [***] shall [***] and [***] to [***] a [***] equal to [***][***]
([***]%) of [***] of all [***] by [***] and/or its [***] in [***]; provided,
however, that if the [***] is [***] from the [***] in [***], then this [***]
shall no longer apply and [***] shall [***] the [***] set forth in [***] on a
[***] basis [***] on the [***] of [***] [***].

4.2.4                        Combination Products.  In determining Net Sales of any Combination
Products under this Agreement, Net Sales shall first be calculated in
accordance with the definition of “Net Sales” above, then multiplied by the
percentage value of the Licensed Product contained in the Combination Product,
such percentage value being the quotient obtained by dividing the current
market price of the Licensed Product by the sum of the separate current market
price of the Licensed Product and other ingredients which are therapeutically
active contained in the Combination Product. 
The current market price of each therapeutically active ingredient and
of the Licensed Product shall be for a quantity comparable to that contained in
the Combination Product and of the same class, purity and potency.  When no current market price is available for
any therapeutically active ingredient or for the Licensed Product, GENENTECH
shall calculate in good faith a hypothetical market price with respect to the
Combination Product, allocating the same proportions of costs, overhead and
profit as are then allocated to all similar substances then being made and
marketed by GENENTECH and having an ascertainable market price; provided,
however, that if IMMUNOGEN in good faith disputes GENENTECH’s
calculation, the Parties shall submit the matter promptly to IMMUNOGEN’S Chief
Executive Officer and a designated officer of GENENTECH with settlement
authority.

Portions
of this Exhibit were omitted and have been filed separately with the Secretary
of the Commission pursuant to the Company’s application requesting confidential
treatment under Rule 24b-2 of the Securities Exchange Act of 1934.

 25
 

4.3                                 One Royalty.  Only one royalty, calculated at the highest
applicable royalty rate under this Section 4, shall be payable to IMMUNOGEN
hereunder for each sale of a Licensed Product.

4.4                                 Royalty Term. GENENTECH shall pay
royalties with respect to each Licensed Product on a country-by-country and
Licensed Product-by-Licensed Product basis until the later of (a) ten (10)
years from the First Commercial Sale of such Licensed Product in such country
and (b) the expiration of the last to expire Valid Claim of the Licensed Patent
Rights covering the Licensed Product in such country.   Following such royalty term, GENENTECH shall
have a fully paid-up, irrevocable, freely transferable and sublicensable
license in such country under the relevant Licensed Patent Rights and Licensed
Technology, to Develop, have Developed, make, have made, use, have used, sell,
have sold, offer for sale, import and have imported such Licensed Product in
such country.

4.5                                 Payment Terms.

(a)                                  Payment
of Milestones; Payment of Royalties; Royalty Reports.  All [***] Milestone payments shall be made
within [***] days after the first achievement of each of the [***] Milestones
described above.  All [***] Milestones
payments shall be paid no later than the [***] of the [***] of the [***]
following the [***] in which the applicable [***] Milestone is achieved,
including in any circumstance in which [***] Milestones are achieved in the
[***].  Subject to the other terms of
this Agreement (including Section 4.1 above), GENENTECH shall make any
milestone payments owed to IMMUNOGEN hereunder in United States Dollars, using
the wire transfer provisions of this Section 4.4.  Subject to the other terms of this Agreement
(including Sections 4.2, 4.3 and 4.4 above), GENENTECH shall make any royalty
payments owed to IMMUNOGEN in United States Dollars, quarterly within [***]
days following the end of each calendar quarter for which such royalties are
deemed to occur (as provided in the next sentence), using the wire transfer
provisions of this Section 4.5.  For
purposes of determining when a sale of any Licensed Product occurs under this
Agreement, the sale shall be deemed to occur on the earlier of (i) the date the
Licensed Product is [***] or (ii) the date of the [***] the [***] of the
Licensed Product.  Each royalty payment
shall be accompanied by a report for each country in the Territory in which
sales of Licensed Products occurred in the calendar quarter covered by such statement,
specifying:  the gross sales (if
available) and Net Sales in each country’s currency; the applicable royalty
rate under this Agreement; the royalties payable in

Portions
of this Exhibit were omitted and have been filed separately with the Secretary
of the Commission pursuant to the Company’s application requesting confidential
treatment under Rule 24b-2 of the Securities Exchange Act of 1934.

 26
 

each country’s
currency, including an accounting of deductions taken in the calculation of Net
Sales; the applicable exchange rate to convert from each country’s currency to
United States Dollars under this Section 4.5; and the royalties payable in
United States Dollars.

(b)                                 Foreign
Currency Exchange.  All royalties
shall be payable in full in the United States in United States Dollars,
regardless of the countries in which sales are made. For the purpose of
computing Net Sales for Licensed Products sold in any currency other than
United States Dollars, the quarterly royalty payment will be calculated as
follows:

(A/B) x C = United
States Dollars royalty payment on foreign current sales, where

A = foreign
current “Net Sales” (as defined above) per quarter;

B = foreign exchange conversion rate, expressed in
local currency per United States Dollar (using as the applicable foreign
exchange rate the average of the rate published in the [***] of the [***], for
the [***] of the calendar quarter); and

C = the royalty
rate applicable to such Net Sales under this Agreement.

(c)                                  Tax
Withholding; Restrictions on Payment.   All payments hereunder shall be made free and
clear of any taxes, duties, levies, fees or charges, except for withholding
taxes (to the extent applicable). 
GENENTECH shall make any applicable withholding payments due on behalf
of IMMUNOGEN and shall promptly provide IMMUNOGEN with written documentation of
any such payment sufficient to satisfy the requirements of the United States
Internal Revenue Service relating to an application by IMMUNOGEN for a foreign
tax credit for such payment.  If by law,
regulations or fiscal policy of a particular country in the Territory,
remittance of royalties in United States Dollars is restricted or forbidden,
written notice thereof shall promptly be given to IMMUNOGEN, and payment of the
royalty shall be made by the deposit thereof in local currency to the credit of
IMMUNOGEN in a recognized banking institution designated by IMMUNOGEN by
written notice to GENENTECH.  When in any
country in the Territory the law or regulations prohibit both the transmittal
and the deposit of royalties on sales in such country, royalty payments shall
be suspended for as long a such prohibition is in effect and as soon as such
prohibition ceases to be in effect, all royalties that GENENTECH would have
been under an obligation to transmit or deposit but for the prohibition shall
forthwith be deposited or transmitted, to the extent allowable.

Portions
of this Exhibit were omitted and have been filed separately with the Secretary
of the Commission pursuant to the Company’s application requesting confidential
treatment under Rule 24b-2 of the Securities Exchange Act of 1934.

 27
 

(d)                                 Wire
Transfers.  All payments hereunder
shall be made to IMMUNOGEN by bank wire transfer in immediately available funds
to the account designated by IMMUNOGEN by written notice to GENENTECH from time
to time.

4.6                                 Overdue Royalties.  Subject to the other terms of this Agreement,
royalties not paid within the time period set forth in this Section 4 shall
bear interest at a rate of [***] percent ([***]%) per month from the due date
until paid in full.

4.7                                 Records Retention; Review.

(a)                                  Royalties.  Commencing as of the date of First Commercial
Sale of the first Licensed Product, GENENTECH and its Sublicensees shall keep
for at least [***] ([***]) years from the end of the calendar year to which
they pertain complete and accurate records of sales by GENENTECH or its
Sublicensees, as the case may be, of each Licensed Product, in sufficient
detail to allow the accuracy of the royalties to be confirmed.

(b)                                 Fully
Burdened Manufacturing Costs. 
Commencing as of the Effective Date, IMMUNOGEN shall keep for at least
[***] years following the end of the calendar year to which they pertain
complete and accurate records of all of IMMUNOGEN’s Fully Burdened
Manufacturing Costs for Preclinical Materials and Clinical Materials supplied to
GENENTECH (or its Sublicensee) hereunder, in sufficient detail to allow the
accuracy of the Fully Burdened Manufacturing Costs to be confirmed.

(c)                                  Review.  Subject to the other terms of this Section
4.7(c), at the request of either Party, upon at least [***] business days’
prior written notice from the requesting Party, and at the expense of the
requesting Party (except as otherwise provided herein), the other Party shall
permit an independent certified public accountant reasonably selected by the
requesting Party and reasonably acceptable to the other Party to inspect
(during regular business hours) the relevant records required to be maintained
by the other Party under this Section 4.7. 
At IMMUNOGEN’s request (which shall not be made more frequently than
once per year during the Term), the accountant shall be entitled to review the
then-preceding [***] years of GENENTECH’s records under this Section 4.7 for
purposes of verifying GENENTECH’s royalty calculations. At GENENTECH’s request
(which shall not be made more frequently than once per year during the Term),
the accountant shall be entitled to review the then-preceding [***] years of
IMMUNOGEN’s records under this Section 4.7 for purposes of verifying IMMUNOGEN’s
Fully Burdened Manufacturing Cost calculations. In every case the accountant

Portions
of this Exhibit were omitted and have been filed separately with the Secretary
of the Commission pursuant to the Company’s application requesting confidential
treatment under Rule 24b-2 of the Securities Exchange Act of 1934.

 28
 

must have previously
entered into a confidentiality agreement with both Parties substantially
similar to the provisions of Section 4 and limiting the disclosure and use of
such information by such accountant to authorized representatives of the
Parties and the purposes germane to this Section 4.7.  Results of any such review shall be made
available to both Parties and shall be binding on both Parties.  Each Party agrees to treat the results of any
such accountant’s review of the other Party’s records under this Section 4.7 as
Confidential Information of the other Party subject to the terms of Section
5.  If any review reveals a deficiency in
the calculation of royalties resulting from any underpayment by GENENTECH,
GENENTECH shall promptly pay IMMUNOGEN the amount remaining to be paid (plus
interest thereon at the rate provided in Section 4.6 above), and if such
underpayment is by [***] percent ([***]%) or more, GENENTECH shall pay all
costs and expenses of the review.  If any
review reveals a deficiency in the calculation of Fully Burdened Manufacturing
Costs resulting from any overpayment by GENENTECH, IMMUNOGEN shall promptly
refund GENENTECH the amount of any such overpayment (plus interest thereon at
the rate provided in Section 4.6 above), and if such overpayment is by [***]
percent ([***]%) or more, IMMUNOGEN shall pay all costs and expenses of the
review.

5. 
TREATMENT OF CONFIDENTIAL INFORMATION

5.1                                 Confidential Information.  During the Term, in the course of performance
of this Agreement, each Party may disclose to the other Party proprietary
technical and business information of the disclosing Party, including
techniques, data, inventions, practices, methods, knowledge, know-how, test
data and results (including from pre-clinical and/or human clinical testing),
analytical and quality control data, cost, sales, manufacturing, patent data
and any other information disclosed hereunder. 
Such information of the disclosing Party hereunder, if so identified in
writing by the disclosing Party to the receiving Party either pursuant to this
Section 5.1 or otherwise upon disclosure to the receiving Party, shall be
considered “Confidential Information” of the disclosing Party.  Each Party agrees that it will take the same
commercially reasonable steps to protect the confidentiality of other Party’s
Confidential Information as it takes to protect its own proprietary and
confidential information. For a period of [***] years after the receipt of any
such Confidential Information from the disclosing Party hereunder, subject to
the terms of this Section 5, the receiving Party shall keep confidential and
not disclose (by publication or otherwise) such Confidential Information of the
other Party, and shall not use,

Portions
of this Exhibit were omitted and have been filed separately with the Secretary
of the Commission pursuant to the Company’s application requesting confidential
treatment under Rule 24b-2 of the Securities Exchange Act of 1934.

 29
 

publish or otherwise
disclose Confidential Information of the other Party for any purpose other than
those contemplated by this Agreement (including as reasonably necessary to
exercise any rights or perform any obligations under this Agreement).
Notwithstanding the foregoing, it is understood and agreed that the receiving
Party’s obligations of confidentiality and non-use herein shall not apply to
the extent that it can be established by competent written records that any
such information:

(a)                                  is,
at the time of disclosure by the disclosing Party hereunder, or thereafter
becomes, a part of the public domain or publicly known or available, other than
through any act or omission of the receiving Party in breach of its obligations
under this Section 5; or

(b)                                 was
known to the receiving Party at the time of disclosure to it by the disclosing
Party; or

(c)                                  is,
at the time of disclosure by the disclosing Party hereunder, or thereafter
becomes, known to the receiving Party from a source that had a lawful right to
disclose such information to others; or

(d)                                 was
independently developed by the receiving Party without use or reference to any
Confidential Information of the disclosing Party.

5.2                                 Permitted Disclosures; Publications.

(a)                                  Permitted
Disclosures.  Each Party shall be
entitled to disclose Confidential Information of the other Party to employees
of the receiving Party, provided that such employees are already bound by
obligations of confidentiality to their employer, and also to Affiliates,
consultants, agents and Third Parties for any purpose provided for in this Agreement,
provided that any such Affiliate, consultant, agent or other Third Party has
first agreed in writing to confidentiality restrictions and obligations at
least as protective as this Section 5, in each case for any purpose
contemplated by this Agreement (including as reasonably necessary to exercise
any rights or perform any obligations under this Agreement).

(b)                               Review
of Publications.  Each Party shall
consult with the other Party prior to the submission of any manuscript for
publication if the publication will contain any Confidential Information of the
other Party, unless the applicable laws and regulations prohibit such
consultation.  Such consultation shall
include providing a copy of the proposed manuscript to the other Party at least
[***] days prior to the proposed date of submission to a publisher,

Portions
of this Exhibit were omitted and have been filed separately with the Secretary
of the Commission pursuant to the Company’s application requesting confidential
treatment under Rule 24b-2 of the Securities Exchange Act of 1934.

 30
 

incorporating
appropriate changes proposed by the other Party regarding its Confidential
Information into the manuscript submission and deleting all Confidential
Information of the other Party as it may request; provided, however,
that the other Party’s review hereunder shall be deemed completed at the end of
such [***]-day period.

(c)                                  Other
Permitted Disclosures. 
Notwithstanding the foregoing, Confidential Information of either Party
may be disclosed by the other Party to the extent such disclosure is reasonably
necessary for filing or prosecuting patent applications or maintaining patents,
prosecuting or defending litigation, enforcing rights and/or obligations under
this Agreement, complying with applicable laws, regulations or court order or
conducting pre-clinical or human clinical testing of Licensed Products; provided,
that, if a Party is required by applicable law, regulation or court
order to make such disclosure of the other Party’s Confidential Information,
[***] of such other Party’s Confidential Information required to be disclosed.

5.3                                 Use of Names; Press  Releases.

(a)                                  Use
of Names.  A Party may not use the
name of the other Party (or any trademarks or tradenames of the other Party) in
any press release or any other publicity or advertising without the prior
written consent of the other Party.

(b)                                 Press
Releases.  Except as provided in
Sections 5.1 and 5.2 above, a Party may not issue a press release or otherwise
publicize or disclose any information related to this Agreement or the terms or
conditions hereof, without the prior written consent of the other Party.  Once any written text is approved for
disclosure by both Parties as provided herein, either Party may make subsequent
or repeated public disclosures of the contents thereof [***] the [***] of the
other Party, so long as such subsequent disclosures continue to be correct and
presented in appropriate context. 
Nothing in the foregoing, however, shall prohibit a Party from making
such disclosures regarding this Agreement or the terms thereof to the extent
deemed necessary under applicable federal or state securities laws or any rule
or regulation of any nationally recognized securities exchange, subject to the
terms of Section 5.2 above regarding disclosures required to comply with
applicable laws, regulations or court order.

5.4                                 Integration;
Survival.  As to the subject
matter of this Agreement, this Section 5 supersedes any confidential disclosure
agreements between the Parties.  Section
5 shall survive termination or expiration of this Agreement.

Portions
of this Exhibit were omitted and have been filed separately with the Secretary
of the Commission pursuant to the Company’s application requesting confidential
treatment under Rule 24b-2 of the Securities Exchange Act of 1934.

 31
 

6. 
PROVISIONS CONCERNING THE FILING, PROSECUTION AND

MAINTENANCE OF PATENT RIGHTS

6.1                                 Ownership of Intellectual Property.

(a)                                  Sole
Inventions.  IMMUNOGEN shall own all
inventions (whether or not patentable) made during the course of and pursuant
to activities carried out under this Agreement solely by employees of or agents
or others obligated to assign inventions to IMMUNOGEN. GENENTECH shall own all
inventions (whether or not patentable) made during the course of and pursuant
to activities carried out under this Agreement solely by employees of or agents
or others obligated to assign inventions to GENENTECH.  The Party solely owning any inventions
hereunder shall be the sole owner of any inventorship certificate(s), patent
application(s) and patent(s) thereon. All determinations of inventive
contribution shall be as determined by United States laws of inventorship.  Subject to the terms of Section 6.2 below
relating to IMMUNOGEN sole inventions, the Party solely owning an invention hereunder
will be solely responsible, at its own cost and expense and in its sole
discretion, for the filing, prosecution and maintenance of any inventorship
certificate(s), patent application(s) and patent(s) thereon.

(b)                                 Joint
Inventions.  Inventions made during
the course of and pursuant to activities carried out under this Agreement
jointly by employees of or agents of or others obligated to assign inventions
to IMMUNOGEN and GENENTECH shall be jointly owned by IMMUNOGEN and GENENTECH.
All determinations of inventive contribution shall be as determined by United
States laws of inventorship.  The Parties
shall also jointly own any inventorship certificate(s), patent application(s)
and patent(s) on any joint inventions hereunder. The terms of Section 6.2 below
relating to joint inventions shall apply to any inventorship certificate(s),
patent application(s) and patent(s) thereon.

(c)                                  Disclosure.  As regards any IMMUNOGEN sole or joint
invention hereunder or any GENENTECH joint inventions hereunder, each Party
shall provide to the other Party any invention disclosure made during the
course of performance of this Agreement and relating to activities carried out
hereunder within [***] days after such Party receives such disclosure from its
employees, agents or others obligated to assign inventions to such Party.

(d)                                 Other
Agreements.  An invention made during
the course of and pursuant to other agreements between the Parties, including
agreements related to process development or

Portions
of this Exhibit were omitted and have been filed separately with the Secretary
of the Commission pursuant to the Company’s application requesting confidential
treatment under Rule 24b-2 of the Securities Exchange Act of 1934.

 32
 

manufacturing,
will be considered to be made under that separate agreement and not under this
Agreement.

6.2                                 Patent Filing, Prosecution and Maintenance.

(a)                                  Sole
IMMUNOGEN Inventions.  Subject to the other terms of this
Section 6.2(a) and Section 6.2(b), IMMUNOGEN shall have the right to prepare,
file, prosecute, obtain and maintain, at its sole cost and expense, all
Licensed Patent Rights. IMMUNOGEN agrees that with respect to such Licensed
Patent Rights licensed exclusively to GENENTECH hereunder, (i) any such
preparation, filing, prosecution and maintenance shall be conducted with
commercially reasonable diligence by IMMUNOGEN, using patent counsel selected
by IMMUNOGEN and reasonably acceptable to GENENTECH. In any case IMMUNOGEN (i)
will provide GENENTECH with a copy of any proposed patent application covering
any such Licensed Patent Rights for review and comment reasonably in advance of
filing (which shall under no circumstances be in excess of [***] days), and
(ii) will keep GENENTECH reasonably informed of the status of such filing,
prosecution and maintenance, including, without limitation, (A) by providing
GENENTECH with copies of all communications received from or filed in patent
office(s) with respect to such filing, and (B) by providing GENENTECH, a
reasonable time prior to taking or failing to take any action that would affect
the scope or validity of any such of any such filing (including the
substantially narrowing, cancellation or abandonment of any claim(s) without
retaining the right to pursue such subject matter in a separate application, or
the failure to file or perfect the filing of any claim(s) in any country), with
prior written notice of such proposed action or inaction so that GENENTECH has
a reasonable opportunity to review and comment. Any application for extension
of Licensed Patent Rights in the Territory due to delays in regulatory review
with respect to any Licensed Product shall be filed only upon mutual written
agreement of the Parties.  If IMMUNOGEN
fails to undertake the filing(s) of any patent application with respect to any
invention under such Licensed Patent Rights within [***] days after receipt of
written notice from GENENTECH that GENENTECH believes filing of such an
application by IMMUNOGEN is appropriate, GENENTECH may undertake such filing(s)
at its own expense, in which case IMMUNOGEN will assign all of its rights to
such invention to GENENTECH and any subsequently issued patent thereon will be
owned solely by GENENTECH.

Portions
of this Exhibit were omitted and have been filed separately with the Secretary
of the Commission pursuant to the Company’s application requesting confidential
treatment under Rule 24b-2 of the Securities Exchange Act of 1934.

 33
 

(b)                                 Joint
Inventions. As regards any joint invention by the Parties hereunder, the
Party from whom the majority of the data underlying any such joint invention
arose (the “controlling Party”) will have the first right, but not the
obligation, to undertake filing(s), prosecution and maintenance of inventorship
certificate(s), patent application(s) and patent(s) thereon.  In connection with any such filing(s), the
filing Party will use patent counsel mutually acceptable to each Party (in its
reasonable determination) and the Parties will, prior to filing of the patent
application, agree on mutually acceptable sharing of the costs and expenses of
such filing(s), prosecution and maintenance. 
In any case the filing Party (i) will provide the non-controlling Party
with a copy of any such proposed patent application for review and comment reasonably
in advance of filing, and (ii) will keep the non-controlling Party reasonably
informed of the status of such filing, prosecution and maintenance, including,
without limitation, (A) by providing the non-controlling Party with copies of
all communications received from or filed in patent office(s) with respect to
such filing, and (B) by providing the non-controlling Party, a reasonable time
prior to taking or failing to take any action that would affect the scope or
validity of any such filing (including the substantially narrowing, cancellation
or abandonment of any claim(s) without retaining the right to pursue such
subject matter in a separate application, or the failure to file or perfect the
filing of any claim(s) in any country), with prior written notice of such
proposed action or inaction so that the non-controlling Party has a reasonable
opportunity to review and comment. If the Party from whom the majority of the
data underlying any such joint invention fails to undertake the filing(s) of
any such patent application with respect to any such invention within [***]
days after receipt of written notice from the other Party that the other Party
believes filing(s) of such an application by such Party is appropriate, such
other Party may undertake such filing(s) at its own expense, in which case the
non-filing Party will assign all of its rights to such joint invention to the
filing Party and any subsequently issued patent thereon will be owned solely by
the filing Party.  Either Party may
assign its rights hereunder to any jointly owned invention, inventorship
certificate, patent application or patent to the other Party, who will then
have the right, in its discretion, to assume the filing, prosecution and/or
maintenance thereof as the sole owner thereof and at its sole cost and expense.

6.3                                 Notice of Infringement.  If, during the Term of this Agreement, either
Party learns of any actual, alleged or threatened infringement by a Third Party
of any Licensed Patent Rights under this Agreement, such Party shall promptly
notify the other Party and shall provide such other Party with available
evidence of such infringement.

Portions
of this Exhibit were omitted and have been filed separately with the Secretary
of the Commission pursuant to the Company’s application requesting confidential
treatment under Rule 24b-2 of the Securities Exchange Act of 1934.

 34
 

6.4                                 Infringement of Patent Rights.

(a)                                  Sole
IMMUNOGEN Inventions.  IMMUNOGEN
shall have the first right (but not the obligation), at its own expense, to
bring suit (or take other appropriate legal action) against any actual, alleged
or threatened infringement of the Licensed Patent Rights solely owned by
IMMUNOGEN under this Agreement, with legal counsel of its own choice.  GENENTECH shall have the right, at its own
expense, to be represented in any such action by IMMUNOGEN by counsel of
GENENTECH’s own choice; provided, however, that under no
circumstances shall the foregoing affect the right of IMMUNOGEN to control the
suit as described in the first sentence of this Section 6.4(a).  If IMMUNOGEN does not file any action or
proceeding against such infringement within [***] days after the later of (i)
IMMUNOGEN’s notice to GENENTECH under Section 6.3 above, (ii) GENENTECH’s
notice to IMMUNOGEN under Section 6.3 above, or (iii) a written request from
GENENTECH to take action with respect to such infringement, then GENENTECH
shall have the right (but not the obligation), at its own expense, to bring
suit (or take other appropriate legal action) against such actual, alleged or
threatened infringement, with legal counsel of its own choice. IMMUNOGEN shall
have the right, at its own expense, to be represented in any such action by
GENENTECH by counsel of IMMUNOGEN’s own choice. 
Any damages, monetary awards or other amounts recovered, whether by
judgment or settlement, pursuant to any suit, proceeding or other legal action
taken under this Section 6.4(a), shall first be applied to reimburse the costs
and expenses (including attorneys’ fees) of the Party bringing such suit or
proceeding or taking such other legal action, then to the costs and expenses
(including attorneys’ fees), if any, of the other Party.  Any amounts remaining shall be allocated as
follows: (A) if GENENTECH is the Party bringing such suit or proceeding or
taking such other legal action, [***] percent ([***]%) to GENENTECH and [***]
percent ([***]%) to IMMUNOGEN,  (B) if
IMMUNOGEN is the Party bringing such suit or proceeding or taking such other
legal action, [***] percent ([***]%) to IMMUNOGEN and (C) if the suit is
brought jointly, [***] percent ([***]%) to each Party.  If a Party brings any such action or
proceeding hereunder, the other Party agrees to be joined as party plaintiff if
necessary to prosecute such action or proceeding, and to give the Party
bringing such action or proceeding reasonable assistance and authority to file
and prosecute the suit; provided, however,

Portions
of this Exhibit were omitted and have been filed separately with the Secretary
of the Commission pursuant to the Company’s application requesting confidential
treatment under Rule 24b-2 of the Securities Exchange Act of 1934.

 35
 

that neither Party
shall be required to transfer any right, title or interest in or to any
property to the other Party or any Third Party to confer standing on a Party
hereunder.

(b)                               Infringement
of Joint Inventions.  As to the any
actual, alleged or threatened infringement of any Patent Rights jointly owned
by IMMUNOGEN and GENENTECH under this Agreement, including actions against any
alleged infringer, the Parties hereto will consult with each other in good
faith regarding the best manner in which to proceed.  The Parties agree as a basic principle that
in the case of such actions against infringers, the expenses incurred and
damages awarded shall be for the account of the Party or Parties who take such
actions to the extent of their financial participation therein.

6.5                                 Third Party Patents.  If any Third Party claims that a patent it
owns or controls claims any aspect of a Licensed Product or its manufacture,
use or sale, the Party with notice of such claim shall notify the other Party
promptly, and the Parties shall as soon as practicable thereafter discuss in
good faith regarding the best response.

6.6           Trademarks.  All Licensed Products shall be sold under one
(1) or more trademarks and tradenames selected and owned by GENENTECH (or its
Sublicensee) in the Territory.  GENENTECH
(or its Sublicensee) shall control the preparation, prosecution and maintenance
of applications related to all such trademarks and tradenames in the Territory,
at its sole cost and expense and at its sole discretion.  IMMUNOGEN shall notify GENENTECH promptly
upon learning of any actual, alleged or threatened infringement of a trademark
or tradename applicable to a Licensed Product in the Territory, or of any
unfair trade practices, trade dress imitation, passing off of counterfeit
goods, or like offenses in the Territory. 
All of the costs, expenses and legal fees in bringing, maintaining and
prosecuting any action to maintain, protect or defend any owned by GENENTECH
(or its Sublicensee) hereunder, and any damages or other recovery, shall be
GENENTECH’s (or its Sublicensee’s) sole responsibility, and taken in its sole
discretion.

6.7           Integration; Survival.  This Section 6 supersedes any provisions to
the contrary in the HER2 License Agreement and that certain [***] Process
Development Agreement by and between the Parties dated as of [***].  This Section 6 shall survive termination or
expiration of this Agreement.

Portions
of this Exhibit were omitted and have been filed separately with the Secretary
of the Commission pursuant to the Company’s application requesting confidential
treatment under Rule 24b-2 of the Securities Exchange Act of 1934.

 36
 

7.  TERM AND
TERMINATION

7.1                                 Term; Expiration. The term of this
Agreement (“Term”) shall expire upon the
expiration of the final royalty payment obligation under Section 4.4
above.  Upon such expiration of the Term
of this Agreement, GENENTECH shall have a fully paid-up, irrevocable, freely
transferable and sublicensable license in the Territory under the Licensed
Patent Rights and Licensed Technology, to Develop, have Developed, make, have
made, use, have used, sell, have sold, offer for sale, import and have imported
any and all Licensed Products in the Territory.

7.2.                              Termination.  Subject to the other terms of this Agreement:

(a)                                  Breach.
A Party may terminate this Agreement and the licenses granted herein, effective
upon written notice to the other Party, upon any breach by the other Party of
any material obligation or condition of this Agreement, which material breach
remains uncured [***] days after the non-breaching Party gives a first written
notice to the other Party describing such breach in reasonable detail; provided,
however, that in the event of a [***] by [***] under this Agreement, the
[***] shall be [***] (in lieu of [***]) but the other terms of this Section
7.2(a) shall apply to termination in connection with any such payment
breach.  Notwithstanding anything set
forth herein, if the asserted material breach is cured or shown to be non-existent
within the applicable cure period, the first notice of breach hereunder shall
be deemed automatically withdrawn and of no effect.

(b)                                 Bankruptcy.
A Party may terminate this Agreement, effective on written notice to the other
Party, in the event the other Party shall have become insolvent or bankrupt, or
shall have made an assignment for the benefit of its creditors, or there shall
have been appointed a trustee or receiver of the other Party or for all or a
substantial part of its property, or any case or proceeding shall have been
commenced or other action taken by or against the other Party in bankruptcy or
seeking reorganization, liquidation, dissolution, winding-up, arrangement,
composition or readjustment of its debts or any other relief under any
bankruptcy, insolvency, reorganization or other similar act or law of any
jurisdiction now or hereafter in effect, or there shall have been issued a
warrant of attachment, execution, distraint or similar process against any substantial
part of the property of the other Party, and any such foregoing events shall
have continued for [***] days undismissed, unbonded and undischarged.  Furthermore, all rights and licenses granted
under this Agreement are, and shall be deemed to be, for purposes of Section
365(n) of the United States Bankruptcy Code, licenses of rights to “intellectual
property” as

Portions
of this Exhibit were omitted and have been filed separately with the Secretary
of the Commission pursuant to the Company’s application requesting confidential
treatment under Rule 24b-2 of the Securities Exchange Act of 1934.

 37
 

defined under
Section 101(56) of the United States Bankruptcy Code.  The Parties agree that in the event of the
commencement of a bankruptcy proceeding by or against one Party hereunder under
the United States Bankruptcy Code, the other Party shall be entitled to
complete access to any such intellectual property, and all embodiments of such
intellectual property, pertaining to the rights granted in the licenses hereunder
of the Party by or against whom a bankruptcy proceeding has been commenced,
subject, however, to payment of the milestone amounts and royalties set forth
in this Agreement through the effective date of any termination hereunder.

(c)                                  Unilateral
Termination by GENENTECH.  GENENTECH, in its sole discretion, at any
time may terminate this Agreement, and the rights and obligations hereunder, or
may remove any Licensed Product and the licenses related thereto from operation
of this Agreement, in any case effective [***] days after written notice
thereof to IMMUNOGEN.  In the event of
any termination under this Section 7.2(c) only as to a Licensed Product, the
consequences set forth in Section 7.3 below relating to termination of the
Agreement under this Section 7.2(c) shall apply only with respect to such
terminated Licensed Product, and this Agreement and the rights and obligations
hereunder shall continue in full force and effect as to any and all other
Licensed Products.

7.3                                 Effects of Termination.  Upon any termination of this Agreement by
IMMUNOGEN under Section 7.2(a) or by GENENTECH under Section 7.2(c), as of the
effective date of such termination, all relevant licenses and sublicenses
granted by IMMUNOGEN to GENENTECH hereunder shall terminate automatically.  Notwithstanding the foregoing, (a) no such
termination of this Agreement shall be construed as a termination of any valid
sublicense of any Sublicensee hereunder, and thereafter each such Sublicensee
shall be considered a direct licensee of IMMUNOGEN, provided that (i)
such Sublicensee is then in full compliance with all terms and conditions of
its sublicense, (ii) all accrued payments obligations to IMMUNOGEN have been
paid, and (iii) such sublicensee agrees at least ten (10) days prior to the effective
date of such termination to assume all obligations of GENENTECH under this
Agreement, and (b) GENENTECH and its Sublicensees shall have the right, for
[***] ([***]) months or such longer time period (if any) on which the Parties
mutually agree in writing, to sell or otherwise dispose of all Licensed
Products then on hand, with royalties to be paid to IMMUNOGEN on all Net Sales
of such Licensed Products as provided for in this Agreement.  Nothing set forth in this Section 7 or any
other provision of this Agreement shall entitle

Portions
of this Exhibit were omitted and have been filed separately with the Secretary
of the Commission pursuant to the Company’s application requesting confidential
treatment under Rule 24b-2 of the Securities Exchange Act of 1934.

 38
 

IMMUNOGEN to any
ownership interest in, or to any license under or other rights with respect to
(including any rights to use or request any transfer to IMMUNOGEN or any Third
Party), any Confidential Information of GENENTECH or any Technology or Patent
Rights solely owned by GENENTECH under this Agreement.

7.4                                 Effects of Termination For IMMUNOGEN Breach.  Upon any termination of this Agreement by
GENENTECH under Section 7.2(a), as of the effective date of such termination,
GENENTECH thereafter automatically shall have a fully sublicensable and
transferable, fully paid up (subject to the remainder of this Section 7.4),
exclusive license in the Territory under the Licensed Patent Rights and
Licensed Technology, to Develop, have Developed, make, have made, use, have
used, sell, have sold, offer for sale, import and have imported any and all
Licensed Products in the Territory, provided that GENENTECH shall pay,
for the remainder of the royalty term under Section 4.4 above, [***] of any
payments including milestones or royalties it would [***] to IMMUNOGEN under
this Agreement, a [***] equal to [***] of the [***] that would [***] with
respect to the Licensed Product under Sections 4.2.1, 4.2.2, 4.2.3 and 4.2.4 of
this Agreement.

7.5                                 Remedies.  Except as otherwise expressly set forth in
this Agreement, the termination provisions of this Section 7 are in addition to
any other relief and remedies available to either Party at law.

7.6                                 Surviving Provisions.  Notwithstanding any provision herein to the
contrary, the rights and obligations of the Parties set forth in Sections 4.7,
5, 6, 7.3, 7.4, 7.5, 8, 9, 10 and this Section 7.6, as well as any rights or
obligations otherwise accrued hereunder (including any accrued payment
obligations), shall survive the expiration or termination of the Term of this
Agreement. Without limiting the generality of the foregoing, GENENTECH shall
have no obligation to make any milestone or royalty payment to IMMUNOGEN that
has not accrued prior to the effective date of any termination of this
Agreement, but shall remain liable for all such payment obligations accruing
prior to the effective date of such termination.

8. 
REPRESENTATIONS AND WARRANTIES

8.1                                 IMMUNOGEN Representations.  IMMUNOGEN represents and warrants to
GENENTECH that:  (a) the execution and
delivery of this Agreement and the performance of the transactions contemplated
hereby have been duly authorized by all appropriate IMMUNOGEN

Portions
of this Exhibit were omitted and have been filed separately with the Secretary
of the Commission pursuant to the Company’s application requesting confidential
treatment under Rule 24b-2 of the Securities Exchange Act of 1934.

 39
 

corporate action;
(b) this Agreement is a legal and valid obligation binding upon IMMUNOGEN and
enforceable in accordance with its terms, and the execution, delivery and
performance of this Agreement by the Parties does not conflict with any
agreement, instrument or understanding to which IMMUNOGEN is a party or by
which it is bound; (c) IMMUNOGEN has the full right and legal capacity to grant
the licenses and rights to GENENTECH pursuant to Section 2 above without
violating the rights of any Third Party; and (d) to IMMUNOGEN’s knowledge, no
Patent Rights within the Licensed Patent Rights are invalid or unenforceable or
would infringe Patent Rights of Third Parties, and as of the Effective Date no
patents within the Licensed Patent Rights are expired.

8.2                                 GENENTECH Representations.  GENENTECH represents and warrants to
IMMUNOGEN that:  (a) the execution and
delivery of this Agreement and the performance of the transactions contemplated
hereby have been duly authorized by all appropriate GENENTECH corporate action;
and (b) this Agreement is a legal and valid obligation binding upon GENENTECH
and enforceable in accordance with its terms, and the execution, delivery and
performance of this Agreement by the Parties does not conflict with any
agreement, instrument or understanding to which GENENTECH is a party or by
which it is bound.

8.3                                 No Warranties.

(a)                                  Nothing
in this Agreement is or shall be construed as:

(i)                                     a
warranty or representation by IMMUNOGEN as to the validity or scope of any
patent application or patent within the Licensed Patent Rights;

(ii)                                  a
warranty or representation that anything made, used, sold or otherwise disposed
of under any license granted in this Agreement is or will be free from
infringement of patents, copyrights, and other rights of third parties.

(b)                                 Except
as expressly set forth in this Agreement, NEITHER PARTY MAKES ANY
REPRESENTATIONS OR EXTENDS ANY WARRANTIES OF ANY KIND, EITHER EXPRESS OR
IMPLIED.  THERE ARE NO EXPRESS OR IMPLIED
WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, THAT ANY
LICENSED PRODUCT WILL BE SUCCESSFULLY DEVELOPED OR MARKETED, OR THAT THE
DEVELOPMENT, MANUFACTURE, SALE, IMPORTATION OR USE OF THE LICENSED PRODUCT(S)
WILL NOT INFRINGE ANY PATENT,

Portions
of this Exhibit were omitted and have been filed separately with the Secretary
of the Commission pursuant to the Company’s application requesting confidential
treatment under Rule 24b-2 of the Securities Exchange Act of 1934.

 40
 

COPYRIGHT,
TRADEMARK, OR OTHER RIGHTS, OR ANY OTHER EXPRESS OR IMPLIED WARRANTIES.

8.4                                 Survival. Section 8 shall survive
termination or expiration of this Agreement.

9. 
INDEMNIFICATION; LIABILITY

9.1                                 Indemnification.

(a)                                  GENENTECH
Indemnity.  Subject to Section 9.1(b)
below and the remainder of this Section 9, GENENTECH shall indemnify, defend
and hold harmless IMMUNOGEN, its Affiliates and their respective directors,
officers, employees, and agents and their respective successors, heirs and
assigns (the “Indemnitees”), from and
against any liability, damage, loss or expense (including reasonable attorneys’
fees and expenses of litigation) incurred by or imposed upon such Indemnitees,
or any of them, in connection with any Third Party claims, suits, actions,
demands or judgments, including, without limitation, personal injury and
product liability matters (but excluding any patent, trademark or tradename
infringement matters, which are governed by Section 6 above), that arise out of
or relate to (i) any actions or omissions of GENENTECH or any Sublicensee in
the development, testing, production, manufacture, supply, promotion, import,
sale or use by any person of any Licensed Product (or any component thereof)
manufactured or sold by GENENTECH or any Sublicensee under this Agreement, (ii)
any material breach of this Agreement by GENENTECH, or (iii) negligence or
willful misconduct on the part of GENENTECH, in any such case under this Section
9.1(a) except to the extent of IMMUNOGEN’s responsibility therefor under
Section 9.1(b) below.

(b)                                 IMMUNOGEN
Indemnity.  Subject to Section 9.1(a)
above and the remainder of this Section 9, IMMUNOGEN shall indemnify, defend
and hold harmless GENENTECH, its Affiliates and their respective directors,
officers, employees, and agents, and their respective successors, heirs and
assigns (also the “Indemnitees”),
from and against any liability, damage, loss or expense (including reasonable
attorneys’ fees and expenses of litigation) incurred by or imposed upon such
Indemnitees, or any of them, in connection with any Third Party claims, suits,
actions, demands or judgments, including, without limitation, personal injury
and product liability matters (but excluding any patent, trademark or tradename
infringement matters, which are governed by Section 6 above), that arise out of
or relate to (i) any actions or omissions of 
IMMUNOGEN or subcontractor of IMMUNOGEN in the

Portions
of this Exhibit were omitted and have been filed separately with the Secretary
of the Commission pursuant to the Company’s application requesting confidential
treatment under Rule 24b-2 of the Securities Exchange Act of 1934.

 41
 

development,
testing, production, manufacture or supply of any Licensed Product (or any
component thereof) manufactured and supplied by IMMUNOGEN or any subcontractor
of IMMUNOGEN under this Agreement, (ii) any material breach of this Agreement
by IMMUNOGEN, or (iii) negligence or willful misconduct on the part of IMMUNOGEN,
in any such case under this Section 9.1(b) except to the extent of GENENTECH’s
responsibility therefor under Section 9.1(a) above.

9.2                                 Indemnification Procedures.  In the event that any Indemnitee is seeking
indemnification under Section 9.1 above from a Party (the “Indemnifying
Party”), the other Party shall notify the Indemnifying Party of
such claim with respect to such Indemnitee as soon as reasonably practicable
after the Indemnitee receives notice of the claim, and the Party (on behalf of
itself and such Indemnitee) shall permit the Indemnifying Party to assume
direction and control of the defense of the claim (including the right to
settle the claim solely for monetary consideration) and shall cooperate as
requested (at the expense of the Indemnifying Party) in the defense of the
claim.

9.3                                 Liability.  NOTWITHSTANDING ANYTHING ELSE IN THIS
AGREEMENT OR OTHERWISE, NEITHER PARTY WILL BE LIABLE WITH RESPECT TO ANY
SUBJECT MATTER OF THIS AGREEMENT UNDER ANY CONTRACT, NEGLIGENCE, STRICT
LIABILITY OR OTHER LEGAL OR EQUITABLE THEORY FOR (a) ANY INDIRECT, INCIDENTAL,
CONSEQUENTIAL OR PUNITIVE DAMAGES OR LOST PROFITS OR (b) COST OF PROCUREMENT OF
SUBSTITUTE GOODS, TECHNOLOGY OR SERVICES.

9.4                                 Survival. Section 9 shall survive
termination or expiration of this Agreement.

10. MISCELLANEOUS

10.1                           Entire Agreement; Amendments.  This is the entire Agreement between the
Parties with respect to the subject matter herein, and supersedes any prior
agreements, understandings, negotiations or correspondence between the Parties
respecting the subject matter hereof, whether written or verbal.  No modification or other amendment of this
Agreement shall be effective unless in writing and signed by a fully authorized
representative of each Party.

10.2                           Waiver.  The terms or conditions of this Agreement may
be waived only by a written instrument executed by a duly authorized
representative of the Party waiving compliance.

Portions
of this Exhibit were omitted and have been filed separately with the Secretary
of the Commission pursuant to the Company’s application requesting confidential
treatment under Rule 24b-2 of the Securities Exchange Act of 1934.

 42
 

The failure of
either Party at any time or times to require performance of any provision
hereof shall in no manner affect its rights at a later time to enforce the
same.  No waiver by either Party of any
condition or term shall be deemed as a continuing waiver of such condition or
term or of another condition or term.

10.3                           Governing Law.  This Agreement will be construed, interpreted
and applied in accordance with the laws of the State of California applicable
to contracts entered into and to be performed entirely within the State of
California.

10.4                           Notices.  Any notices, requests, deliveries, approvals
or consents required or permitted to be given under this Agreement to GENENTECH
or IMMUNOGEN shall be in writing and shall be personally delivered or sent by
telecopy (with machine confirmation of transmission) or by overnight courier
providing evidence of receipt or certified mail, return receipt requested,
postage prepaid, in each case to the respective address specified below (or to
such address as may be specified in writing to the other Party hereto):

	
  If to IMMUNOGEN:

  	
   

  	
  ImmunoGen, Inc.

  
	
   

  	
   

  	
  128 Sidney Street

  
	
   

  	
   

  	
  Cambridge, MA 02139-4239

  
	
   

  	
   

  	
  Attn:  Chief Executive Officer

  
	
   

  	
   

  	
  Fax: (617) 995-2510

  
	
   

  	
   

  	
   

  
	
  with a copy to

  	
   

  	
  Mintz, Levin, Cohn, Ferris, Glovsky and Popeo, P.C.

  
	
   

  	
   

  	
  One Financial Center

  
	
   

  	
   

  	
  Boston, MA 02111

  
	
   

  	
   

  	
  Attn: [***], Esq.

  
	
   

  	
   

  	
  (617) 542-2241

  
	
   

  	
   

  	
   

  
	
  If to GENENTECH:

  	
   

  	
  Genentech, Inc.

  
	
   

  	
   

  	
  1 DNA Way 94080

  
	
   

  	
   

  	
  South San Francisco, CA 94080

  
	
   

  	
   

  	
  Attn: Corporate Secretary

  
	
   

  	
   

  	
  Fax: (650) 467-9146

  

 

Such
notices shall be deemed to have been sufficiently given on:  (a) the date sent if delivered in person or
transmitted by telecopy, (b) the next business day after dispatch in the case
of overnight courier or (c) five (5) business days after deposit in the U.S.
mail in the case of certified mail.

Portions
of this Exhibit were omitted and have been filed separately with the Secretary
of the Commission pursuant to the Company’s application requesting confidential
treatment under Rule 24b-2 of the Securities Exchange Act of 1934.

 43
 

10.5                           No Implied Licenses.  Except as expressly set forth elsewhere in
this Agreement, neither Party grants to the other Party any right or license to
any of its intellectual property.

10.6                           Headings.  Section and subsection headings are inserted
for convenience of reference only and do not form part of this Agreement.

10.7                           Assignment.  This Agreement may not be assigned by either
Party without the consent of the other, except that each Party may, without
such consent, assign this Agreement and the rights, obligations and interests
of such Party, in whole or in part, to any of its Affiliates, to any purchaser
of all or substantially all of its assets in the line of business to which this
Agreement pertains or to any successor corporation resulting from any merger or
consolidation of such Party with or into such corporations.

10.8                           Force Majeure.  Neither Party shall be liable for failure of
or delay in performing obligations set forth in this Agreement, and neither
shall be deemed in breach of its obligations, if such failure or delay is due
to natural disasters or any causes beyond the reasonable control of such
Party.  In event of such force majeure,
the Party affected thereby shall use reasonable efforts to cure or overcome the
same and resume performance of its obligations hereunder.

10.9                           Construction.  The Parties hereto acknowledge and agree
that:  (a) each Party and its
counsel reviewed and negotiated the terms and provisions of this Agreement and
have contributed to its revision; (b) the rule of construction to the
effect that any ambiguities are resolved against the drafting Party shall not
be employed in the interpretation of this Agreement; and (c) the terms and
provisions of this Agreement shall be construed fairly as to each Party hereto
and not in a favor of or against any Party, regardless of which Party was
generally responsible for the preparation of this Agreement.

10.10                     Severability.  If any provision(s) of this Agreement are or
become invalid, are ruled illegal by any court of competent jurisdiction or are
deemed unenforceable under then current applicable law from time to time in
effect during the term hereof, it is the intention of the Parties that the
remainder of this Agreement shall not be affected thereby provided that a Party’s
rights under this Agreement are not materially affected.  The Parties hereto covenant and agree to
renegotiate any such term, covenant or application thereof in good faith in
order to provide a reasonably acceptable alternative to the term, covenant or
condition of this Agreement or the application thereof that is invalid, illegal
or unenforceable, it being the intent of the Parties that the basic purposes of
this Agreement are to be effectuated.

Portions
of this Exhibit were omitted and have been filed separately with the Secretary
of the Commission pursuant to the Company’s application requesting confidential
treatment under Rule 24b-2 of the Securities Exchange Act of 1934.

 44
 

10.11                     Status.           Nothing in this Agreement is intended or
shall be deemed to constitute a partner, agency, employer-employee, or joint
venture relationship between the Parties.

10.12                     Dispute Resolution.  The Parties recognize that a bona fide
dispute as to certain matters may from time to time arise during the term of
this Agreement relating to either Party’s rights and/or obligations hereunder
or otherwise relating to the validity, enforceability or performance of this
Agreement, including disputes relating to alleged breach or termination of this
Agreement but excluding any determination of the validity of the Parties’
patents (hereinafter, a “Dispute”).  In
the event of the occurrence of any such Dispute, the Parties pledge to attempt
to resolve it amicably.  Accordingly, if
any Dispute should arise, either Party may, by written notice to the other
Party, have such dispute referred to their respective senior officers
designated below (and to any designated officer of a GENENTECH Sublicensee, if
such Dispute involves such Sublicensee), for attempted resolution by good faith
negotiations commencing promptly after such notice is received; provided,
however, that if the subject matter of such Dispute is within the
purview of the Collaboration Committee, the Parties’ representatives on the
Collaboration Committee shall first attempt to resolve such Dispute before
referring it to the Parties’ senior officers hereunder.  Said designated senior officials of the
Parties are as follows:

	
  For GENENTECH:

  	
   

  	
  Designated officer with settlement authority; and

  
	
   

  	
   

  	
   

  
	
  For IMMUNOGEN:

  	
   

  	
  Chief Executive Officer.

  

 

In the event the
designated senior officials are not able to resolve such Dispute, the Parties
may seek to mediate their Dispute, on terms and with a mediator mutually
agreeable to the Parties, or may seek to arbitrate their Dispute, on mutually
agreed upon terms and conditions, but neither Party shall be required or
obligated to mediate or arbitrate and the dispute resolution provisions of this
Section 10.12 are in addition to any other relief and remedies available to
either Party at law or in equity.

10.13                     Further Assurances.  Each Party agrees to execute, acknowledge and
deliver such further instruments, and to do all other such acts, as may be
necessary or appropriate in order to carry out the purposes and intent of this
Agreement.

Portions
of this Exhibit were omitted and have been filed separately with the Secretary
of the Commission pursuant to the Company’s application requesting confidential
treatment under Rule 24b-2 of the Securities Exchange Act of 1934.

 45
 

10.14                     Counterparts.  This Agreement may be executed simultaneously
in one or more counterparts, each of which shall be deemed an original, but all
of which together shall constitute one and the same instrument.

Portions
of this Exhibit were omitted and have been filed separately with the Secretary
of the Commission pursuant to the Company’s application requesting confidential
treatment under Rule 24b-2 of the Securities Exchange Act of 1934.

[Remainder
of page intentionally left blank.]

 46
 

IN
WITNESS WHEREOF, the Parties have caused this Agreement to be executed by their
duly authorized representatives, effective as of the Effective Date set forth
on the first page hereof.

	
  GENENTECH, INC.

  	
   

  	
  IMMUNOGEN, INC.

  	
   

  	
   

  
	
   

  	
   

  	
   

  	
   

  	
   

  
	
   

  	
   

  	
   

  	
   

  	
   

  
	
  By:

  	
   

  	
   

  	
   

  	
  By:

  	
   

  	
   

  	
   

  	 

	
   

  	
   

  	
   

  	
   

  	
   

  
	
  Title:

  	
   

  	
   

  	
   

  	
  Title:

  	
   

  	
   

  	
   

  
	
   

  	
   

  	
   

  	
   

  	
   

  	
   

  	
   

  
	
  Date:

  	
   

  	
   

  	
   

  	
  Date:

  	
   

  	
   

  	
   

  
												

 

Portions
of this Exhibit were omitted and have been filed separately with the Secretary
of the Commission pursuant to the Company’s application requesting confidential
treatment under Rule 24b-2 of the Securities Exchange Act of 1934.

 47Exhibit 10.2

EXECUTION COPY

LICENSE AGREEMENT

This
License Agreement (the “Agreement”) is made effective as of December 12, 2005
(the “Effective Date”) by and between GENENTECH, INC., a Delaware corporation
having its principal business office at 1 DNA Way, South San Francisco,
California 94080 (“GENENTECH”), and IMMUNOGEN, INC., a Massachusetts
corporation with its principal place of business at 128 Sidney Street,
Cambridge, Massachusetts 02139 (“IMMUNOGEN”). 
GENENTECH and IMMUNOGEN are each hereafter referred to individually as a
“Party” and together as the “Parties”.

WHEREAS,
the Parties entered into the Heads of Agreement (defined below) pursuant to
which IMMUNOGEN granted GENENTECH the right to obtain up to [***] exclusive
options at any given time to obtain an exclusive license to use IMMUNOGEN’s
proprietary maytansinoid conjugation technology with certain proprietary
antibodies of GENENTECH and other binding proteins relating thereto that bind
to any antigen target selected by GENENTECH and determined by IMMUNOGEN to be
available for licensing as described more fully in the Heads of Agreement; and

WHEREAS,
pursuant to the Heads of Agreement, GENENTECH was granted an Exclusive Target
Option (as defined in the Heads of Agreement) with respect to [***] and has
exercised such Exclusive Target Option pursuant to the terms set forth in the
Heads of Agreement, resulting in the grant of an exclusive license from
IMMUNOGEN to GENENTECH on the terms set forth in the Heads of Agreement; and

WHEREAS,
pursuant to the Heads of Agreement, the Parties have agreed to enter into an
agreement setting forth the detailed terms of the exclusive license from
IMMUNOGEN to GENENTECH.

NOW,
THEREFORE, in consideration of the mutual covenants contained herein, and for
other good and valuable consideration, the receipt and adequacy of which are
hereby acknowledged, the Parties hereby agree as follows:

1. 
DEFINITIONS

 

Whenever used in the Agreement with an initial capital
letter, the terms defined in this Section 1 shall have the meanings specified.

Portions of this Exhibit were
omitted and have been filed separately with the Secretary of the Commission
pursuant to the Company’s application requesting confidential treatment under
Rule 24b-2 of the Securities Exchange Act of 1934.

1.1.                              “Adverse Event” shall mean any untoward medical occurrence in a patient or
subject who is administered a Licensed Product, whether or not considered
related to the Licensed Product, including, without limitation, any undesirable
sign (including abnormal laboratory findings of clinical concern), symptom or
disease temporally associated with the use of such Licensed Product.

1.2.                              “Affiliate” shall mean any
corporation, firm, limited liability company, partnership or other entity which
directly or indirectly controls or is controlled by or is under common control
with a Party to this Agreement.  For
purposes of this Section 1.2, “control” means ownership, directly or indirectly
through one or more Affiliates, of fifty percent (50%) or more of the shares of
stock entitled to vote for the election of directors, in the case of a
corporation, or fifty percent (50%) or more of the equity interests in the case
of any other type of legal entity, or status as a general partner in the case
of any partnership, or any other arrangement whereby a Party controls or has
the right to control the Board of Directors or equivalent governing body or
management of a corporation or other entity.

1.3.                              “Agreement” shall mean this
Agreement between the Parties, dated as of the Effective Date, including any
exhibits, schedules or other attachments hereto and incorporated herein, as any
of the foregoing may be validly amended from time to time.  In the event of any inconsistency between the
terms of this Agreement and the terms of any exhibits, schedules or other
attachments incorporated herein, the terms of this Agreement shall govern
unless the Parties expressly agree otherwise in writing.

1.4.                              “Allocable Overhead” shall mean
overhead costs incurred by IMMUNOGEN attributable to IMMUNOGEN’s supervisory
services, occupancy costs, and its payroll, information systems, human
relations, purchasing, accounts receivable or accounts payable functions which
are allocated to company departments based on space occupied or headcount or
another activity-based method, and shall include the “General Administrative
Fee” as defined hereinbelow.  For
purposes of any given calculation of “Allocable Overhead” hereunder, the “General
and Administrative Fee” shall equal [***] percent ([***]%) of the total amount
of Allocable Overhead (as calculated before the inclusion of any such
fee).  However, “Allocable Overhead”
shall not include any costs attributable to general corporate activities,
executive management, investor relations, corporate communications, business
development, legal affairs or finance.

Portions
of this Exhibit were omitted and have been filed separately with the Secretary
of the Commission pursuant to the Company’s application requesting confidential
treatment under Rule 24b-2 of the Securities Exchange Act of 1934.

 2
 

1.5.                              “[***]” shall mean a protein that
corresponds to Swiss-Prot Primary accession number [***], or any variant or
fragments thereof.

1.6.                              “[***] Antibody”
shall mean any monoclonal antibodies Controlled by GENENTECH that bind to [***]
and any other proteins binding to [***], and shall include, without limitation,
any variants (including, without limitation, humanized versions), fragments
(including, without limitation, single-chain versions) or derivatives of any of
the foregoing.

1.7.                              “[***] Product” shall mean any
product containing an anti-[***] monoclonal antibody conjugated to a MAY
Compound.

1.8.                              “Clinical Materials” shall mean (a) supplies of
ansamitocin P-3, and/or any other MAY Compound as manufactured in accordance
with all applicable GMPs and other legal requirements and all applicable
Specifications for such MAY Compound for use in human clinical testing, and (b)
supplies of any Licensed Product as manufactured in accordance with all
applicable GMPs and other legal requirements and all applicable Specifications
for such Licensed Product for use in human clinical testing of any Licensed
Product.

1.9.                              “Collaboration Committee” shall mean
the committee with representatives of each Party established as set forth in
Section 3.4.

1.10.                        “Combination Product” shall mean any Licensed Product
that contains, in addition to any conjugate of a [***] Antibody with any MAY
Compound, one or more other ingredients that has biologic activity as a
therapeutic agent when present alone.

1.11.                        “Confidential Information” shall have the meaning set
forth in Section 5.1.

1.12.                        “Control” or “Controlled”
shall mean, with respect to any Patent Rights or Technology (including, without
limitation, any MAY Compound, [***] Antibody or other proprietary biologic
material covered under this Agreement), the possession by a Party of the
ability to grant a license or sublicense of such patent rights, know-how or
other intellectual property and the rights thereto or to supply such compounds
or materials as provided for in this Agreement without violating the terms of
any arrangement or agreement between such Party and any Third Party.

1.13.                        “Development” and “Develop” shall mean, with respect
to any Licensed Product, all activities with respect to such Licensed Product
relating to research and development in connection with seeking, obtaining
and/or maintaining any Regulatory Approval for such Licensed Product in the
Field in the Territory, including without limitation, all pre-clinical 

Portions
of this Exhibit were omitted and have been filed separately with the Secretary
of the Commission pursuant to the Company’s application requesting confidential
treatment under Rule 24b-2 of the Securities Exchange Act of 1934.

 3
 

research and
development activities, all human clinical studies, all activities relating to
developing the ability to manufacture any Licensed Product or any component
thereof (including, without limitation, process development work), and all
other activities relating to seeking, obtaining and/or maintaining any
Regulatory Approvals from the FDA and/or any Foreign Regulatory Authority.

1.14.                        “Drug Approval Application” shall
mean any application for Regulatory Approval (including pricing and
reimbursement approvals) required prior to any commercial sale or use of a
Licensed Product in any country or jurisdiction in the Territory, including,
without limitation, (a) any NDA or MAA filed with the FDA or any Foreign
Regulatory Authority, and (b) any equivalent application filed with any Foreign
Regulatory Authority for Regulatory Approval (including pricing and
reimbursement approvals) required prior to any commercial sale or use of a
Licensed Product in any country or jurisdiction in the Territory.

1.15.                        “Effective Date” shall mean the date
first written above in the introductory paragraph to this Agreement.

1.16.                        “FDA” shall mean the United States
Food and Drug Administration and any successor agency or authority thereto.

1.17.                        “Field” shall mean any and all human
uses.

1.18.                        “First Commercial Sale” shall mean
the date of the first commercial sale (other than for purposes of obtaining
Regulatory Approval) of a Licensed Product by or on behalf of GENENTECH or any
Sublicensee.

1.19.                        “[***] Indication” shall mean the
[***] use permitted by the FDA or any Foreign Regulatory Authority in any
Regulatory Approval of a given Licensed Product.

1.20.                        “Foreign Regulatory Authority” shall
mean any applicable supranational, national, federal, state or local regulatory
agency, department, bureau or other governmental entity of any country or
jurisdiction in the Territory (other than the FDA in the United States), having
responsibility in such country or jurisdiction for any Regulatory Approvals of
any kind in such country or jurisdiction, and any successor agency or authority
thereto.

1.21.                        “Fully Burdened Manufacturing Cost”
shall mean, with respect to any Preclinical Materials or Clinical Materials
produced by IMMUNOGEN for GENENTECH under this Agreement, the sum of the
following components: (a) the costs of goods produced, as determined by
IMMUNOGEN in accordance with generally accepted accounting principles in 

Portions
of this Exhibit were omitted and have been filed separately with the Secretary
of the Commission pursuant to the Company’s application requesting confidential
treatment under Rule 24b-2 of the Securities Exchange Act of 1934.

 4
 

the United States,
consistently applied, including, without limitation, direct labor, material and
product testing costs of such Preclinical Materials or Clinical Materials; (b)
any Third Party royalty costs directly allocable to the manufacture or use of
such Preclinical Materials or Clinical Materials; (c) all Allocable Overhead on
the cost of goods under clause (a) above; and (d) any other costs borne by
IMMUNOGEN, for the transport, customs clearance, duty, insurance and/or storage
of such Preclinical Materials or Clinical Materials.

1.22.                        “GENENTECH” shall mean Genentech,
Inc., a Delaware corporation, and its successors and permitted assigns under
this Agreement.

1.23.                        “GLPs” shall mean all good
laboratory practices under Title 21 of the United States Code of Federal
Regulations, as amended from time to time.

1.24.                        “GMPs” shall mean all good
manufacturing practices under Title 21 of the United States Code of Federal
Regulations, as amended from time to time.

1.25.                        “Heads of Agreement” shall mean the
Heads of Agreement, dated May 2, 2000, as amended, whereunder the Parties
agreed upon the terms and conditions for a broader arrangement relating to the
conjugation of a larger array of antibodies and binding proteins to maytansine
derivatives such as DM1.

1.26.                        “HER2 License Agreement” shall mean
that certain License Agreement dated as of May 2, 2000, as amended May 3, 2006,
by and between the Parties with respect to the use of IMMUNOGEN’s proprietary
maytansinoid conjugation technology with GENENTECH’s Anti-HER2 antibodies and
other HER-2 binding proteins.

1.27.                        “IMMUNOGEN” shall mean ImmunoGen,
Inc., a Massachusetts corporation, and its successors and permitted assigns
under this Agreement.

1.28.                        “IMMUNOGEN Field” shall mean any and
all uses other  than any use that involves an antibody that binds
to an antigen that is subject to an exclusive license from IMMUNOGEN under, or
arising from, the Heads of Agreement or an antigen that is subject to an
Exclusive Target Option under the Heads of Agreement, during the period that
such exclusive license or Exclusive Target Option remains in effect.

1.29.                        “Improvement” shall mean: (a)
improvements to any MAY Compound, (b) improvements to methods of making
any MAY Compound, and (c) improvements to the conjugation process for
making antibody-drug conjugates that include any MAY Compound (including, for
example, reaction conditions or changes in process that create improvements in 

Portions
of this Exhibit were omitted and have been filed separately with the Secretary
of the Commission pursuant to the Company’s application requesting confidential
treatment under Rule 24b-2 of the Securities Exchange Act of 1934.

 5
 

the yield of such
conjugate).  “Improvement” excludes any
and all of the following items (“GNE Exclusions”): (w) any improvement
that is specific to any antibody-drug conjugates that bind to an antigen that
is subject to an exclusive license from IMMUNOGEN under, or arising from, the
Heads of Agreement or is subject to an Exclusive Target Option under the Heads
of Agreement during the period that such exclusive license or Exclusive Target
Option remains in effect; (x) improvements to [***] or [***], or the [***]
of [***] or [***] of the foregoing; (y) improvements arising out of
GENENTECH [***] or [***] activities (whether or not the associated [***] is the
subject of a license or option to GENENTECH by IMMUNOGEN); or (z) the
[***] or [***] of [***] [***] (i.e.,  the [***] or [***] of such [***] (e.g.,  the [***] of [***] or the [***] of [***] to [***]) and
[***] the manner of [***] such [***] [***]) that binds to an antigen that is
subject to an exclusive license from IMMUNOGEN under, or arising from, the
Heads of Agreement or an antigen that is subject to an Exclusive Target Option
under the Heads of Agreement, during the period that such exclusive license or
Exclusive Target Option remains in effect.

1.30.                        “IND” shall mean an investigational
new drug application (as defined in Title 21 of the United States Code of
Federal Regulations, as amended from time to time) filed or to be filed with
the FDA with regard to any Licensed Product.

1.31.                        “Indemnitees” and “Indemnifying Party” shall have the
meanings set forth in Section 9.

1.32.                        “Licensed Patent Rights” shall mean
any and all Patent Rights in the Field in the Territory which are Controlled by
IMMUNOGEN as of the Effective Date or become Controlled by IMMUNOGEN during the
Term, to the extent that any of the foregoing is necessary or useful for the
Development, manufacture, use, import, export or sale of any Licensed Product
(or any component thereof) in the Field in the Territory.  The Licensed Patent Rights as of the
Effective Date include, without limitation, the patents and patent applications
set forth in the Existing License Agreement, as updated from time to time.

1.33.                        “Licensed Product” shall mean any
product containing any conjugate of a [***] Antibody with any MAY Compound, and
shall include, without limitation, any formulation thereof (including, without
limitation, any lyophilized, liquid, sustained release or aerosolized
formulation).  “Licensed Product” shall
also include any and all Combination Products (if any).

Portions
of this Exhibit were omitted and have been filed separately with the Secretary
of the Commission pursuant to the Company’s application requesting confidential
treatment under Rule 24b-2 of the Securities Exchange Act of 1934.

 6
 

1.34.                        “Licensed Technology” shall mean any
and all Technology which relates to the use of any Licensed Product in the
Field in the Territory which is Controlled by IMMUNOGEN as of the Effective
Date or becomes Controlled by IMMUNOGEN during the Term, to the extent that any
of the foregoing relates to any Licensed Patent Rights or is necessary or useful
for the Development, manufacture, use, import, export or sale of any Licensed
Product in the Field in the Territory.

1.35.                        “MAA” shall mean an application
filed with the relevant Foreign Regulatory Authority in Europe seeking
Regulatory Approval to market and sell any Licensed Product in Europe or any
country or territory therein for a particular indication within the Field.

1.36.                        “MAY Compound” shall mean any and
all maytansinoid compounds (including, without limitation, maytansine,
ansamitocin P-3 and DM1), whether produced by a botanical source, natural
fermentation or chemical synthesis, and shall include, without limitation, all
variants, fragments or derivatives of any of the foregoing, in each case owned
or otherwise Controlled by IMMUNOGEN. 
MAY shall include, without limitation, that certain maytansine
derivative known as “DM1” whose more specific chemical name is N2’-deacetyl-N2’-(3-mercapto-1-oxopropyl)-maytansine.

1.37.                        “NDA” shall mean a new drug
application (as defined in Title 21 of the United States Code of Federal
Regulations, as amended from time to time) filed with the FDA seeking
Regulatory Approval to market and sell any Licensed Product in the United
States for a particular indication within the Field.

1.38.                        “Net Sales”
shall mean, as to each calendar quarter during the Term, the gross invoiced
sales prices charged for all Licensed Products sold by GENENTECH or its
Sublicensees to Third Parties throughout the Territory during such calendar
quarter, less the following amounts incurred or paid by GENENTECH or its
Sublicensees during such calendar quarter with respect to sales of Licensed
Products regardless of the calendar quarter in which such sales were made:

(a)                                  trade,
cash and quantity discounts or rebates actually allowed or taken, including
discounts or rebates to governmental or managed care organizations;

(b)                                 credits
or allowances actually given or made for rejection of or return of, and for
uncollectible amounts on, previously sold Licensed Products or for retroactive
price reductions (including Medicare and similar types of rebates);

Portions of this Exhibit were omitted and have
been filed separately with the Secretary of the Commission pursuant to the
Company’s application requesting confidential treatment under Rule 24b-2 of the
Securities Exchange Act of 1934.

 7
 

(c)                                  any
charges for insurance, freight, and other transportation costs directly related
to the delivery of Licensed Product to the extent included in the gross
invoiced sales price;

(d)                                 any
tax, tariff, duty or governmental charge levied on the sales, transfer,
transportation or delivery of a Licensed Product (including any tax such as a
value added or similar tax or government charge) borne by the seller thereof,
other than franchise or income tax of any kind whatsoever; and

                (e)                                  any
import or export duties or their equivalent borne by the seller.  “Net Sales” shall not include sales or
transfers between GENENTECH and its Sublicensees, unless the Licensed Product
is consumed by the Sublicensee.

1.39.                        “Patent Rights” shall mean the
rights and interests in and to any and all issued patents and pending patent
applications (including inventor’s certificates and utility models) in any
country or jurisdiction in the Territory, including any and all provisionals,
non-provisionals, substitutions, continuations, continuations-in-part,
divisionals and other continuing applications, supplementary protection
certificates, renewals, and all letters patent on any of the foregoing, and any
and all reissues, reexaminations, extensions, confirmations, registrations and
patents of addition on any of the foregoing.

1.40.                        “Phase II Clinical Study” shall
mean, as to a particular Licensed Product for a particular indication, a
controlled and lawful study in humans of the safety, dose ranging and efficacy
of such Licensed Product for such indication, which is prospectively designed
to generate sufficient data (if successful) to commence a Phase III Clinical
Trial of such Licensed Product for such indication.

1.41.                        “Phase III Clinical Trial” shall mean, as to a
particular Licensed Product for a particular indication, a controlled and
lawful study in humans of the safety and efficacy of such Licensed Product for
such indication, which is prospectively designed to demonstrate statistically
whether such Licensed Product is safe and effective for use in such indication
in a manner sufficient to file an NDA to obtain Regulatory Approval to market
and sell that Licensed Product in the United States for the indication under
investigation in such study.

1.42.                        “Phase III Equivalent Decision” shall mean the date
(if any) on which GENENTECH (or its Sublicensee) decides, based on notification
and input from the FDA, that the data and results generated from the Phase II
Clinical Studies of a Licensed Product for a

Portions
of this Exhibit were omitted and have been filed separately with the Secretary
of the Commission pursuant to the Company’s application requesting confidential
treatment under Rule 24b-2 of the Securities Exchange Act of 1934.

 8
 

particular
indication are sufficient, without any Phase III Clinical Trial of such
Licensed Product for such indication, to support the filing of an NDA to obtain
Regulatory Approval to market and sell that Licensed Product in the United
States for the indication under investigation.

1.43.                        “Preclinical Materials” shall mean (a) supplies of
ansamitocin P-3, DM1 and/or any other MAY Compound as manufactured in
accordance with all applicable legal requirements and all applicable
Specifications for such MAY Compound for use in preclinical testing, and (b)
supplies of any Licensed Product as manufactured in accordance with all
applicable legal requirements and all applicable Specifications for such
Licensed Product for use in preclinical testing of any Licensed Product.

1.44.                        “Regulatory Approval” shall mean any
and all approvals (including pricing and reimbursement approvals), product and
establishment licenses, registrations or authorizations of any kind of the FDA
or any Foreign Regulatory Authority necessary for the development, pre-clinical
and/or human clinical testing, manufacture, quality testing, supply, use,
storage, importation, export, transport, marketing and sale of a Licensed
Product (or any component thereof) for use in the Field in any country or other
jurisdiction in the Territory.  “Regulatory
Approval” shall include, without limitation, any NDA, MAA or other Drug
Approval Application.

1.45.                        “[***] Indication” shall mean the
[***] use permitted by the FDA or any Foreign Regulatory Authority in any
Regulatory Approval of a given Licensed Product and with respect to which
GENENTECH has made a [***] based on [***] that such indication will [***] at
least a $[***] in [***] in the [***].

1.46.                        “Specifications” shall mean any
specifications agreed upon in writing by the Parties relating to the
manufacturing and supply of any MAY Compound and/or Licensed Product hereunder.

1.47.                        “Sublicensee” shall have the meaning
set forth in Section 2.2, and “Material Sublicensee”
shall have the meaning set forth in Section 3.3.

1.48.                        “Technology” shall mean and include
any and all unpatented proprietary ideas, inventions, discoveries, Confidential
Information, biologic materials, data, results, formulae, designs,
specifications, methods, processes, formulations, techniques, ideas, know-how,
technical information (including, without limitation, structural and functional
information), process information, pre-clinical information, clinical
information, and any and all proprietary

Portions
of this Exhibit were omitted and have been filed separately with the Secretary
of the Commission pursuant to the Company’s application requesting confidential
treatment under Rule 24b-2 of the Securities Exchange Act of 1934.

 9
 

biological,
chemical, pharmacological, toxicological, pre-clinical, clinical, assay, control
and manufacturing data and materials.

1.49.                        “Term” shall mean the period
commencing on the Effective Date and continuing until the expiration or
termination of this Agreement in accordance with the terms hereof (including
Section 7).

1.50.                        “Territory” shall mean all countries
and jurisdictions of the world.

1.51.                        “[***] Indication” shall mean the
[***] use permitted by the FDA or any Foreign Regulatory Authority in any
Regulatory Approval of a given Licensed Product and with respect to which
GENENTECH has made a [***] based on [***] that such indication will [***] at
least $[***] in [***] in the [***].

1.52.                        “Third Party” shall mean any entity
other than GENENTECH, IMMUNOGEN and their respective Affiliates.

1.53.                        “Third Party Payments” shall have
the meaning set forth in Section 4.2.2.

1.54.                        “Valid Claim” shall mean a claim in
an issued, unexpired patent within the Licensed Patent Rights that (i) has not
been finally cancelled, withdrawn, abandoned or rejected by any administrative
agency or other body of competent jurisdiction, and (ii) has not been revoked,
held invalid, or declared unpatentable or unenforceable in a decision of a
court or other body of competent jurisdiction that is unappealable or
unappealed within the time allowed for appeal, and (iii) has not been rendered
unenforceable through disclaimer or otherwise, and (iv) is not lost through an
interference proceeding.

2.  GRANT OF
RIGHTS

2.1.                              License Grants.

(a)                                  License
to GENENTECH.  IMMUNOGEN hereby
grants to GENENTECH an exclusive (even as to IMMUNOGEN) royalty-bearing license
within the Territory, including the right to grant sublicenses as described in
Section 2.2 below, under the Licensed Patent Rights and Licensed Technology, to
Develop, have Developed, make, have made, use, have used, sell, have sold,
offer for sale, import, have imported, export and have exported Licensed
Products in the Field in the Territory, subject to the other terms and
conditions of this Agreement.

Portions
of this Exhibit were omitted and have been filed separately with the Secretary
of the Commission pursuant to the Company’s application requesting confidential
treatment under Rule 24b-2 of the Securities Exchange Act of 1934.

 10
 

(b)                                 License
to IMMUNOGEN.  GENENTECH hereby
grants to IMMUNOGEN a non-exclusive, royalty-free license (i) under
GENENTECH’s intellectual property interest in Improvements, to develop, make,
use, sell, offer for sale, import, and export any product that is not a
Licensed Product or a [***] Product, only within the IMMUNOGEN Field and subject
to Section 2.3(b) below and the remaining terms of this Section 2.1(b); and
(ii) also under GENENTECH’s intellectual property interest in Improvements, to
otherwise exploit Improvements for all uses within the IMMUNOGEN Field, subject
to Section 2.3(b) below and the remaining terms of this Section 2.1(b).  The foregoing license includes the right to
sublicense the rights granted under this Section 2.1(b) only if all of the
following three conditions (i), (ii) and (iii) are met:

 (i)                                  the sublicense is limited to the IMMUNOGEN Field;

 (ii)                               the sublicense is granted only in connection with
a license to IMMUNOGEN MAY Technology (where “IMMUNOGEN
MAY Technology” means Technology Controlled by IMMUNOGEN and
used in the conjugation of MAY Compounds to binding proteins), and the rights
granted for IMMUNOGEN MAY Technology are of the same scope (e.g., for the same product or technology and within the same
field and the same territory) as the rights granted for GENENTECH’s
Improvements; and

 (iii)                            GENENTECH obtains Substantially Similar Grant
Back Rights without incurring an obligation to pay any additional consideration
(either to IMMUNOGEN or to IMMUNOGEN’s sublicensee).  “Substantially Similar
Grant Back Rights” means non-exclusive rights in and to that
sublicensee’s “improvements” (improvements to MAY Compounds, methods of making
MAY Compounds, and methods of making antibody-drug conjugates) that are of
substantially the same scope (e.g., within
the same field and the same territory) as the rights granted in and to
Improvements under this Agreement. 
(GENENTECH may obtain such rights directly from IMMUNOGEN’s sublicensee
or indirectly through IMMUNOGEN; if GENENTECH obtains such rights from
IMMUNOGEN, IMMUNOGEN may have obtained such rights under license or by transfer
of ownership).

Nothing
in this Agreement or the course of dealings between the Parties or usage or
custom in the industry or trade shall be construed to confer any other rights
or licenses to any other intellectual property Controlled by either Party or
its Affiliates by implication, estoppel or

Portions
of this Exhibit were omitted and have been filed separately with the Secretary
of the Commission pursuant to the Company’s application requesting confidential
treatment under Rule 24b-2 of the Securities Exchange Act of 1934.

 11
 

otherwise.  GENENTECH has no obligation to [***] in any
[***] or [***] of [***] to [***] or a [***] with respect to [***].

2.2                                 Sublicenses.  GENENTECH
shall have the right freely to grant sublicenses to all or any portion of its
rights under the license rights granted pursuant to Section 2.1(a) hereof to
any Affiliate or Third Party (in any case, a “Sublicensee”);
provided, however, that (a) each such sublicense shall be
consistent with the terms and conditions of this Agreement, and
(b) GENENTECH shall remain obligated to ensure payment of all of its
milestone and royalty obligations as set forth in Section 4 hereof.

2.3                                 IMMUNOGEN Retained Rights and Covenants; GENENTECH
Technology or Patent Rights.

(a)                                  Retained
Rights.  Subject to the other terms
of this Agreement, including, without limitation, Section 2.3(b) hereof,
IMMUNOGEN retains the right to use the Licensed Technology and practice the
Licensed Patent Rights (i) to perform its work under Sections 3.3, 3.4, 3.5 and
3.6 hereof relating to the Collaboration Committee and to manufacture and
supply Preclinical Materials and Clinical Materials for GENENTECH (and its
Sublicensees), and (ii) to develop, have developed, make, have made, use,
have used, sell have sold, offer for sale, import, have imported, export and
have exported any product that is not a Licensed Product or a [***] Product,
subject to Section 2.3(b) below.

(b)                                 Covenants.  It is hereby further agreed that (i) during
the Term of this Agreement, IMMUNOGEN shall not Develop, have Developed, make,
have made, use, have used, sell, have sold, offer for sale, import, have
imported, export and have exported any [***] Product, which restriction shall
be [***] for [***] of this Agreement if, during a [***] prior to expiration or termination
of this Agreement, [***] is [***] or [***] with a [***], if [***] is subject to
a [***] of [***], or if this Agreement is [***] pursuant to [***], and (ii)
during the Term of this Agreement, and for [***] (which [***] shall not apply
in connection with expiration of this Agreement under [***] below or in
connection with [***] of this Agreement by [***] under [***] below, but which
shall apply in connection with any other [***] of this Agreement, including by
[***] under [***] below), IMMUNOGEN shall not grant to any Third Party any
license or other right under any Patent Rights or Technology owned or
Controlled by

Portions
of this Exhibit were omitted and have been filed separately with the Secretary
of the Commission pursuant to the Company’s application requesting confidential
treatment under Rule 24b-2 of the Securities Exchange Act of 1934.

 12
 

IMMUNOGEN to Develop,
have Developed, make, have made, use, have used, sell, have sold, offer for
sale, import, have imported, export and have exported, any [***] Product.

(c)                                  No
Rights to GENENTECH Technology or Patent Rights.  Except
for the license granted to IMMUNOGEN by GENENTECH in Section 2.1(b) above,
nothing in this Section 2.3 or any other provision of this Agreement shall be
construed as a grant to IMMUNOGEN of any license or other rights with respect
to any Technology (including, without limitation, any Confidential Information)
or Patent Rights owned or Controlled (in whole or in part) by GENENTECH.

3.  DEVELOPMENT AND
COMMERCIALIZATION

OF LICENSED PRODUCTS.

3.1                                 Development and Commercialization.

(a)                                  Responsibility.  On and after the Effective Date,
except as otherwise agreed in writing with respect to certain process
development and manufacturing activities, GENENTECH shall have full control and
authority over, and sole responsibility for, all Development and
commercialization of Licensed Products in the Field in the Territory,
including, without limitation, (i) all pre-clinical Development activities
(including any pharmaceutical development work on formulations or process
development relating to any Licensed Product), (ii) all activities related to
human clinical trials (including any phase I clinical studies, any Phase II
Clinical Studies or any Phase III Clinical Trials), (iii) all activities relating
to manufacture and supply of [***] Antibodies, all MAY Compounds (including
ansamitocin P-3 and DM1) and all Licensed Products, solely to the extent such
activities relate to the development and commercialization of Licensed Products
(including all required process development and scale up work with respect
thereto), (iv) all marketing, promotion, sales, distribution, import and export
activities relating to any Licensed Product (including any post-marketing
trials or databases and post-marketing safety surveillance), and (v) all
activities relating to any regulatory filings, registrations, applications and
Regulatory Approvals relating to any of the foregoing (including any INDs or
foreign equivalents, any manufacturing facility validation and/or licensure,
any Drug Approval Applications and any other Regulatory Approvals).  Except as described in the next sentence,
GENENTECH shall own all data, results and all other information arising from
any such activities under this Agreement, including, without limitation, all
regulatory filings, registrations, applications and Regulatory Approvals
relating to Licensed Products (including any INDs or foreign equivalents, any
Drug Approval Applications and any other Regulatory Approvals), and all of the
foregoing information, documentation and materials shall be considered
Confidential Information and Technology solely owned by GENENTECH.  IMMUNOGEN shall own all data, results

Portions of this Exhibit were omitted and have
been filed separately with the Secretary of the Commission pursuant to the
Company’s application requesting confidential treatment under Rule 24b-2 of the
Securities Exchange Act of 1934.

 13
 

and all other information arising from IMMUNOGEN’s
activities relating to the manufacture and supply of MAY Compounds (including
ansamitocin P-3 and DM1) to GENENTECH, and all of the foregoing information,
documentation and materials shall be considered Confidential Information and
Technology solely owned by IMMUNOGEN.  All
activities relating to Development and commercialization under this Agreement
shall be undertaken at GENENTECH’s sole cost and expense, except as otherwise
expressly provided in this Agreement.

(b)                                 Due Diligence.  GENENTECH will exercise its
commercially reasonable efforts and diligence in Developing and commercializing
Licensed Products in accordance with its business, legal, medical and
scientific judgment, and in undertaking investigations and actions required to
obtain appropriate Regulatory Approvals necessary to market Licensed Products
in the Field in the Territory, such reasonable efforts and diligence to be in
accordance with the efforts and resources GENENTECH would use for a compound
owned by it or to which it has rights, which is of similar market potential at
a similar stage in development as the applicable Licensed Product, taking into
account the competitiveness of the marketplace, the proprietary position of the
Licensed Product, the relative potential safety and efficacy of the Licensed
Product, the regulatory requirements involved in its Development,
commercialization and Regulatory Approval,  the cost of goods and availability of capacity to
manufacture and supply the Licensed Product at commercial scale, the
profitability of the applicable Licensed Product, and other relevant factors
including, without limitation, technical, legal, scientific or medical
factors.  In the event that GENENTECH
fails to use due diligence as required hereunder, then on a Licensed
Product-by-Licensed Product and country-by-country basis as to the Licensed
Product in the country in which GENENTECH has failed to use due diligence as
required hereunder, IMMUNOGEN’s exclusive remedy shall be, in its sole
discretion (i) to terminate the licenses granted under Section 2.1 this
Agreement for breach under Section 7.2(a) below

Portions
of this Exhibit were omitted and have been filed separately with the Secretary
of the Commission pursuant to the Company’s application requesting confidential
treatment under Rule 24b-2 of the Securities Exchange Act of 1934.

 14
 

(including the notice and cure provisions therein) or (ii) to convert the
licenses granted under Section 2.1 of this Agreement from exclusive licenses to
non-exclusive licenses, in either case only as such licenses apply to such
Licensed Product in such country, which termination or conversion, as the case
may be, shall be effective upon expiration of the cure period specified in
7.2(a) below provided that such failure remains uncured upon such expiration.

3.2                                 Updates and Reports; Exchanges of Adverse Event Information.

(a)                                  Updates and Reports. 
GENENTECH shall keep IMMUNOGEN informed of the progress of GENENTECH’s
efforts to Develop and commercialize Licensed Products in the Field in the
Territory as provided in this Section 3.2(a). 
GENENTECH (or its Sublicensee) shall provide IMMUNOGEN with brief
written reports as provided herein no less frequently than on each anniversary
of the Effective Date during the Term (commencing with the first anniversary of
the Effective Date).  Such reports shall
summarize GENENTECH’s material efforts to Develop and commercialize all
Licensed Products hereunder, identify the Drug Approval Applications with
respect to any Licensed Product that GENENTECH and its Sublicensees have filed,
sought or obtained in the prior twelve (12)-month period, and any they
reasonably expect to make, seek or attempt to obtain in the following twelve
(12)-month period.  In addition,
GENENTECH (or its Sublicensee) shall provide IMMUNOGEN with prompt written
notice of the occurrence of any event giving rise to an obligation to make a
milestone payment to IMMUNOGEN under Section 4.1, and shall provide IMMUNOGEN
with prompt written notice of the occurrence of the First Commercial Sale of
any particular Licensed Product. All such reports and notices shall be sent to
the attention of IMMUNOGEN’s designated representative, who shall be its Chief
Executive Officer unless IMMUNOGEN otherwise notifies GENENTECH.

(b)                                 Adverse Events.  In addition to such reports,
GENENTECH agrees to provide IMMUNOGEN with Adverse Event information and
product complaint information relating to Licensed Products (but not relating
to any other products of GENENTECH, including any antibody that may be included
in a Licensed Product, to the extent that antibody is used in its “naked” form
or in connection with a different effector molecule) as compiled and prepared
by GENENTECH in the normal course of business in connection with the
Development, commercialization or sale of any Licensed Product, within time
frames consistent with reporting obligations under applicable laws and
regulations.  To the extent it could
reasonably apply or

Portions
of this Exhibit were omitted and have been filed separately with the Secretary
of the Commission pursuant to the Company’s application requesting confidential
treatment under Rule 24b-2 of the Securities Exchange Act of 1934.

 15
 

could reasonably be relevant to a Licensed Product, IMMUNOGEN agrees to
provide GENENTECH with Adverse Event and product complaint information relating
to any product containing any MAY Compound that is compiled and prepared by
IMMUNOGEN or any Third Party in the normal course of business in connection
with the development, commercialization or sale of any such product, within
time frames consistent with reporting obligations under applicable laws and
regulations; provided, however, that the foregoing shall not
require IMMUNOGEN to violate any agreements with or confidentiality obligations
owed to any Third Party.  GENENTECH shall
provide its Adverse Event and product complaint information hereunder to
IMMUNOGEN’s designated representative, who shall be its Chief Regulatory
Officer unless IMMUNOGEN otherwise notifies GENENTECH. IMMUNOGEN shall provide
its Adverse Event and product complaint information hereunder to GENENTECH’s
designated representative, who shall be the head of its Drug Safety group in
GENENTECH’S Medical Affairs Department unless GENENTECH otherwise notifies
IMMUNOGEN.

(c)                                  Confidential Information.  All
reports, updates, Adverse Event, product complaint and other information
provided by one Party to the other Party under this Agreement (including under
this Section 3), shall be considered Confidential Information of the disclosing
Party, subject to the terms of Section 5.

3.3                                 Reasonable Assistance by IMMUNOGEN.  In connection
with the exclusive grant of rights to GENENTECH under Section 2.1 above, and
subject to the other terms of this Agreement, IMMUNOGEN shall provide GENENTECH
(and any Sublicensee of GENENTECH with respect to all of GENENTECH’s license
rights hereunder to make or have made all Licensed Products or any particular
Licensed Product(s) throughout the Territory or in a particular geographic
region of the Territory, and/or all of GENENTECH’s license rights hereunder to
Develop or commercialize all Licensed Products or any particular Licensed
Product(s) throughout the Territory  or
in a particular geographic region of the Territory (in any case, a “Material Sublicensee”)) such
information and materials comprising the Licensed Technology and/or Licensed
Patent Rights as GENENTECH (or its Material Sublicensee) may reasonably
request.  Without limiting the generality
of the foregoing, IMMUNOGEN shall provide all of such technical assistance
within IMMUNOGEN’s area of expertise (or its subcontractors) concerning the
Development and commercialization of Licensed Products as

Portions
of this Exhibit were omitted and have been filed separately with the Secretary
of the Commission pursuant to the Company’s application requesting confidential
treatment under Rule 24b-2 of the Securities Exchange Act of 1934.

 16
 

may be reasonably requested by GENENTECH (or its Material Sublicensee)
from time to time during the Term, provided that such technical assistance and
expertise is within the scope of the Licensed Technology and/or Licensed Patent
Rights covered under this Agreement. 
Such technical assistance and expertise shall include, but not be
limited to, visits by IMMUNOGEN personnel to GENENTECH and visits by GENENTECH
to IMMUNOGEN (or its subcontractors), at GENENTECH’s expense, at such times and
for such periods of time as may be reasonably acceptable to the Parties.   Without limiting the generality of the
foregoing, within [***] ([***]) days after GENENTECH’s reasonable written
request, IMMUNOGEN shall deliver to GENENTECH a list or description of the
documents and information that embody the Licensed Technology.  GENENTECH 
will inform IMMUNOGEN which of those identified documents and
information GENENTECH believes are reasonably related to its exercise of the
license rights under this Agreement and, within [***] days after that
identification, IMMUNOGEN shall deliver to GENENTECH a copy of those documents
and other information.

3.4                                 Collaboration Committee.

(a)                                  Mandate of Committee.  Promptly
after the Effective Date, the Parties shall form a “Collaboration Committee” to serve as a forum for
coordination and communication between the Parties with respect to activities
related to Licensed Products for which the Parties agree there is a need for
coordination and communication (including, without limitation, all process
science and process development work, formulation work, and quality control/
assurance work hereunder), and to assist GENENTECH in its exercise of its
rights to make or have made Licensed Products under this Agreement.  Within [***] days after the Effective Date,
the Parties shall each nominate an equal number of representatives (which shall
be no less than two (2) each) for membership on the Collaboration Committee.  Each Party may change its representative(s)
as it deems appropriate by notice to the other Party.  The input of the IMMUNOGEN representatives on
the Collaboration Committee shall be fully considered by the Collaboration
Committee; provided, however, that all decisions of the
Collaboration Committee shall be subject to final approval by GENENTECH.

(b)                                 Chair of Committee; Meetings.  The
Parties hereby agree that (i) the chair of the Collaboration Committee shall be
one of the GENENTECH representatives on the Collaboration Committee, as
designated by GENENTECH; provided, however, that [***] the [***]
after the Effective Date, the Collaboration Committee shall be [***] by a [***]
on the

Portions of this Exhibit were omitted and have
been filed separately with the Secretary of the Commission pursuant to the Company’s
application requesting confidential treatment under Rule 24b-2 of the
Securities Exchange Act of 1934.

 17
 

Collaboration Committee (as designated by [***]) and an [***] on the
Collaboration Committee (as designated by [***]); (ii) all decisions of the
Collaboration Committee shall be subject to the approval of the GENENTECH chair
(including [***] the [***] there is a [***]); (iii) the Collaboration Committee
shall meet on a semi-annual basis or other schedule agreed upon by the Parties,
unless at least thirty (30) days in advance of any meeting the chair (or
co-chairs during the first twelve (12) months) of the Collaboration Committee
determine that there is no need for a meeting (in which instance, the next
Collaboration Committee meeting shall also be scheduled as agreed upon by the
Parties); (iv) the location of meetings of the Collaboration Committee shall
alternate between IMMUNOGEN’s offices in Massachusetts and GENENTECH’s offices
in California, unless otherwise agreed by the Parties and, as agreed upon by
the Parties, Collaboration Committee meetings may be face-to-face or may be
conducted through teleconferences and/or videoconferences.  In addition to its Collaboration Committee
representatives, each Party shall be entitled to have other employees attend
such meetings to present and participate, though not in a decision-making
capacity.  Each Party shall bear all
costs and expenses, including travel and lodging expense, that may be incurred
by its Collaboration Committee representatives or other of its attendees at
Collaboration Committee meetings, as a result of such meetings hereunder.  Minutes of each Collaboration Committee
meeting will be transcribed and issued to members of the Collaboration Committee
by the chair (or the GENENTECH co-chair, as the case may be) within thirty (30)
days after each meeting, and such minutes shall be reviewed and modified as
mutually required to obtain approval of such minutes promptly thereafter.

3.5                                 Supply of Preclinical Materials.  During the Term of this Agreement, IMMUNOGEN
shall supply to GENENTECH (or its Material Sublicensee) with such quantities of
Preclinical Materials as may be reasonably requested by GENENTECH (or its
Material Sublicensee) in order to conduct all pre-clinical Development
activities relating to Licensed Products. 
GENENTECH (or its Material Sublicensee) shall order all amounts of
Preclinical Materials, and IMMUNOGEN shall deliver all such ordered amounts, in
accordance with advance ordering timeframes and delivery timeframes to be agreed
upon by the Parties through the Collaboration Committee.  IMMUNOGEN shall use its commercially
reasonable efforts to deliver such amounts of Preclinical Materials ordered in
accordance with the foregoing (including such agreed upon timeframes) in a timely
manner.  In connection with any ordering
of

Portions
of this Exhibit were omitted and have been filed separately with the Secretary
of the Commission pursuant to the Company’s application requesting confidential
treatment under Rule 24b-2 of the Securities Exchange Act of 1934.

 18
 

Preclinical
Materials by GENENTECH (or its Material Sublicensee), IMMUNOGEN shall provide
GENENTECH (or its Material Sublicensee) promptly with IMMUNOGEN’s good faith
estimate of the Fully Burdened Manufacturing Cost for manufacture and supply of
such Preclinical Materials.  IMMUNOGEN’s
price to supply Preclinical Materials to GENENTECH (or its Material
Sublicensee) shall equal [***]% of IMMUNOGEN’s Fully Burdened Manufacturing
Cost for such Preclinical Materials as approved by GENENTECH (or its Material
Sublicensee).  Nothing herein shall
preclude GENENTECH from making its own arrangements for manufacture and supply
of Preclinical Materials on its own or with Third Parties, in exercise of its
license rights under Section 2.1.  GENENTECH
hereby agrees that (a) it shall not use the Preclinical Materials in any human
subject, (b) it shall use the Preclinical Materials in compliance with all
applicable federal, state and local laws and regulations, and (c) it (as a
matter of contract between itself and IMMUNOGEN) shall assume all liability for
damages that may arise from the use, storage and disposal of any Preclinical
Materials to the extent provided pursuant to Section 9 below.  GENENTECH shall be entitled to transfer
Preclinical Materials to any Third Party under terms obligating such Third
Party not to transfer or use such Preclinical Materials except in compliance
with the foregoing clauses (a) and (b) of this Section 3.5.

3.6                                 Supply of Clinical Materials.  During the Term of this Agreement, IMMUNOGEN
shall supply to GENENTECH (or its Material Sublicensee) with such quantities of
Clinical Materials as may be reasonably requested by GENENTECH (or its Material
Sublicensee) in order to conduct all human clinical trials of Licensed Products
through non-pivotal Phase II Clinical Studies. 
To the extent GENENTECH requests IMMUNOGEN to manufacture Clinical
Materials as provided in the foregoing sentence, IMMUNOGEN and GENENTECH shall
enter into separate supply and quality agreements detailing the terms of supply
for any Clinical Materials that IMMUNOGEN is so requested to supply to
GENENTECH for the purpose of conducting clinical trials.  GENENTECH (or its Material Sublicensee) shall
order all amounts of Clinical Materials, and IMMUNOGEN shall deliver all such
ordered amounts, in accordance with forecasting parameters, advance ordering
timeframes and delivery timeframes to be agreed upon by the Parties through the
Collaboration Committee.  IMMUNOGEN shall
use its commercially reasonable efforts to deliver such amounts of Clinical
Materials ordered in accordance with the foregoing (including such agreed upon
timeframes) in a timely manner.  In
connection with any ordering of Clinical Materials by GENENTECH (or its 

Portions
of this Exhibit were omitted and have been filed separately with the Secretary
of the Commission pursuant to the Company’s application requesting confidential
treatment under Rule 24b-2 of the Securities Exchange Act of 1934.

 19
 

Material
Sublicensee), IMMUNOGEN shall provide GENENTECH (or its Material Sublicensee)
promptly with IMMUNOGEN’s good faith estimate of the Fully Burdened
Manufacturing Cost for manufacture and supply of such Clinical Materials.  IMMUNOGEN’s price to supply Clinical
Materials to GENENTECH (or its Material Sublicensee) shall equal [***]% of
IMMUNOGEN’S Fully Burdened Manufacturing Cost for such Clinical Materials as
approved by GENENTECH (or its Material Sublicensee).  Nothing herein shall preclude GENENTECH from
making its own arrangements for manufacture and supply of Clinical Materials on
its own or with Third Parties, in exercise of its license rights under Section
2.1. GENENTECH hereby agrees that (a) it shall use the Clinical Materials in
compliance with all applicable federal, state and local laws, and (b) it (as a
matter of contract between itself and IMMUNOGEN) shall [***] all [***] for
[***] that may arise from the [***] and [***] of such Clinical Materials to the
extent provided pursuant to Section 9 below. GENENTECH shall be entitled to
transfer Clinical Materials to any Third Party under terms obligating such
Third Party not to transfer or use such Clinical Materials except in compliance
with the foregoing clause (a) of this Section 3.6.

3.7                                 Purchase of Equipment.  If, during the Term of this Agreement,
IMMUNOGEN determines in good faith that it is necessary or advisable to
purchase equipment or instruments in order to perform any of its obligations to
manufacture Preclinical Materials and Clinical Materials under Sections 3.5 or
3.6 of this Agreement, then IMMUNOGEN shall provide the Collaboration Committee
with written notice of such determination, along with the estimated price for
such purchase and quality parameters for the equipment or instruments, for the
Collaboration Committee’s approval of such price and features.  Promptly after the consummation of such
purchase, assuming that the Collaboration Committee has provided its approval
hereunder, IMMUNOGEN shall provide GENENTECH with a copy of the invoice or
invoices reflecting such purchase, and GENENTECH shall reimburse IMMUNOGEN for
the purchase of all such approved equipment hereunder within [***] days of its
receipt of such invoice from IMMUNOGEN; provided, however, that
no costs reimbursed by GENENTECH hereunder (or depreciation of such purchased
equipment or instruments) shall be includible or included within the
calculation of any Fully Burdened Manufacturing Costs under this Agreement.

Portions
of this Exhibit were omitted and have been filed separately with the Secretary
of the Commission pursuant to the Company’s application requesting confidential
treatment under Rule 24b-2 of the Securities Exchange Act of 1934.

 20
 

4.  PAYMENTS
AND ROYALTIES

4.1                                 Milestone Payments for Licensed Products.

4.1.1                        Milestones.  In consideration of the grant of the license
by IMMUNOGEN hereunder, and subject to the other terms of this Agreement,
GENENTECH will make the following nonrefundable, noncreditable (except as
expressly provided in Section 4.1.2 below) payments to IMMUNOGEN, on the
payment terms in Section 4.5:

	
  [***] Milestones

  	
   

  	
  Milestone Payment

  
	
  Effective Date

  	
   

  	
  $

  	
  1 Million

  
	
   

  	
   

  	
   

  
	
  [***] for a Licensed Product

  	
   

  	
  $

  	
  [***]

  
	
   

  	
   

  	
   

  
	
  [***] of [***] in [***] for a
  [***]

  	
   

  	
  $

  	
  [***]

  
	
   

  	
   

  	
   

  
	
  [***] of [***] of [***]

  	
   

  	
   

  
	
  [***] in [***] for a [***]

  	
   

  	
   

  
	
  [***] or [***]

  	
   

  	
   

  
	
  [***] for a [***]

  	
   

  	
  $

  	
  [***]

  
	
   

  	
   

  	
   

  
	
  [***] of [***] by the [***]

  	
   

  	
   

  
	
  for a [***] for [***]

  	
   

  	
  $

  	
  [***]

  
	
   

  	
   

  	
   

  
	
  [***] of an [***] or other
  [***] in the [***] for a

  	
   

  	
   

  
	
  [***] for [***]

  	
   

  	
  $

  	
  [***]

  
	
   

  	
   

  	
   

  
	
  [***] of a [***] for a 

  	
   

  	
   

  
	
  [***] in [***] for [***]

  	
   

  	
  $

  	
  [***]

  
	
   

  	
   

  	
   

  
	
  [***] of [***] by the [***]
  for a [***] for [***]

  	
   

  	
  $

  	
  [***]

  
	
   

  	
   

  	
   

  
	
  [***] of [***] by the [***]
  for a [***] for a [***]

  	
   

  	
  $

  	
  [***]

  

 

	
  [***] Milestones

  	
   

  	
  Milestone Payment

  
	
  [***] of [***] greater than
  $[***]

  	
   

  	
  $

  	
  [***]

  
	
   

  	
   

  	
   

  
	
  [***] of [***] greater than
  $[***]

  	
   

  	
  $

  	
  [***]

  

 

It is hereby
acknowledged and agreed that any milestone payment shall be made only once,
with respect to the first achievement of the relevant milestone for the first
Licensed Product, regardless of how many times such milestones are achieved by
Licensed Products and

Portions
of this Exhibit were omitted and have been filed separately with the Secretary
of the Commission pursuant to the Company’s application requesting confidential
treatment under Rule 24b-2 of the Securities Exchange Act of 1934.

 21

regardless of how many times a particular Licensed
Product achieves such milestones. GENENTECH shall notify IMMUNOGEN of the
achievement of milestones hereunder as provided in Section 3.2(a) above.

4.1.2                        [***] of [***].  GENENTECH shall be [***] to [***] its [***]
(but not any [***]) [***] to IMMUNOGEN only to the extent set forth in this
Section 4.1.2.  As to the Licensed
Product with respect to which [***] are owed to IMMUNOGEN under this Section
4.1, GENENTECH shall be [***] to [***] percent ([***]%) of each such [***] made
with respect to such Licensed Product hereunder [***] to IMMUNOGEN hereunder
with respect to such Licensed Product, but (a) only if prior to the date of
such [***], GENENTECH (or its Sublicensee) has modified such Licensed Product
such that it would not (even in the absence of the license under this
Agreement) [***] a [***] within the Licensed Patent Rights in the United States
(excluding any Patent Rights [***] by [***] and [***]), and (b) only if such
modification was undertaken (i) to address a [***] or [***] with respect to
such Licensed Product or its Development, manufacture, use or sale, (ii) to
obtain a [***] in the toxicity, safety or efficacy profile of such Licensed
Product, or (iii) to obtain a [***] in the ability to make or have made such
Licensed Product (or any component thereof).

4.2                                 Payment of Royalties; Royalty Rates; Accounting
for Royalties and Records.

4.2.1                        Royalty Payments.  In consideration of the grant of the license
by IMMUNOGEN hereunder, and subject to the other terms of this Agreement
(including the remainder of this Section 4), commencing on the first date of
First Commercial Sale of Licensed Products in such country or jurisdiction in
the Territory, GENENTECH shall pay to IMMUNOGEN the following royalties based
on total Net Sales of all Licensed Products sold by GENENTECH and/or its
Sublicensees, on an incremental basis in each calendar year during the Term, at
the following rates in [***] of the [***]:

	
  For Net Sales of a Licensed Product

  	
   

  	
   

  	
   

  	
   

  
	
  [***] in any Calendar Year

  	
   

  	
   

  	
   

  	
   

  
	
  Duringthe Term:

  	
   

  	
  Royalty Rate (% of Net Sales)

  	
   

  	
   

  
	
   

  	
   

  	
   

  	
   

  	
   

  
	
  Above $[***] and up to
  $[***]

  	
   

  	
  [***]

  	
  %

  	
   

  
	
   

  	
   

  	
   

  	
   

  	
   

  
	
  Above $[***]

  	
   

  	
  [***]

  	
  %

  	
   

  

 

Portions
of this Exhibit were omitted and have been filed separately with the Secretary
of the Commission pursuant to the Company’s application requesting confidential
treatment under Rule 24b-2 of the Securities Exchange Act of 1934.

 22
 

 

	
  For Net Sales of a Licensed Product

  	
   

  	
   

  	
   

  	
   

  
	
  [***] in any Calendar Year

  	
   

  	
   

  	
   

  	
   

  
	
  During the Term:

  	
   

  	
  Royalty Rate (% of Net Sales)

  	
   

  	
   

  
	
   

  	
   

  	
   

  	
   

  	
   

  
	
  Above $[***] and up to
  $[***]

  	
   

  	
  [***]

  	
  %

  	
   

  
	
   

  	
   

  	
   

  	
   

  	
   

  
	
  Above $[***]

  	
   

  	
  [***]

  	
  %

  	
   

  

 

By way of example
only, if during the Term a Licensed Product achieved total Net Sales in a given
calendar of $[***], the applicable royalty rate would be [***]% of Net Sales
for Net Sales up to $[***], and 5.5% of Net Sales for Net Sales over $[***].

4.2.2                        Third Party Royalty Offset.  Subject to the other
terms of this Agreement, on a country-by-country basis, the royalties otherwise
due and payable by GENENTECH under Section 4.2.1 above (but not the royalties
otherwise due and payable by GENENTECH under Section 4.2.3(a) or (b) below)
shall be reduced as provided in this Section 4.2.2:

(a)                                  GENENTECH
Process Development.  Consistent with
GENENTECH’S due diligence obligations under this Agreement, GENENTECH agrees to
exercise due diligence to attempt to Develop a commercially viable
manufacturing process relating to the manufacture and supply of Licensed
Products.  For purposes of this
Agreement, GENENTECH shall determine in good faith the commercial viability of
any such manufacturing process that is Developed hereunder, taking into
account, without limitation, the following factors relevant thereto:  the consistency and reproducibility of the
process itself; the consistency, reproducibility, safety and efficacy of the
resulting conjugated Licensed Products; any regulatory issues; the availability
of capacity; the cost of goods and other components of Fully Burdened
Manufacturing Cost as applied to such process and to the overall manufacture
and supply of Licensed Products; the overall profitability of the Licensed
Products; and the ability to produce at commercial scale quantities.

(b)                                 Partial
Offset.  If GENENTECH is not able to
Develop such a commercially viable manufacturing process after exercising due
diligence as required hereunder, GENENTECH may elect to license a manufacturing
process from a Third Party, and in that event GENENTECH shall be entitled to
offset up to [***] percent ([***]%) of any Third Party Payments it makes in
connection with any license providing rights to any such manufacturing 

Portions
of this Exhibit were omitted and have been filed separately with the Secretary
of the Commission pursuant to the Company’s application requesting confidential
treatment under Rule 24b-2 of the Securities Exchange Act of 1934.

 23
 

process against
the royalties due to IMMUNOGEN pursuant to Section 4.2.1 above, subject to the
clause (d) of this Section 4.2.2. 
GENENTECH shall not be entitled to the offset under this clause (b) if
it fails to exercise due diligence as required hereunder.

(c)                                  Full
Offset.  If GENENTECH determines in
good faith that it is necessary, in order to exploit the license granted to it
under Section 2.1 of this Agreement in any country, to make royalty payments to
any Third Party (“Third Party Payments”)
under any license agreement that GENENTECH determines, in good faith, is
necessary in connection with the Development, manufacture, use or sale of any
MAY Compound, the linker of any MAY Compound to a [***] Antibody, and/or the
conjugation of a [***] Antibody to any MAY Compound (including, without
limitation, DM1) as part of any Licensed Product, then in any such case the
royalties due to IMMUNOGEN pursuant to Section 4.2.1 above for such Licensed
Product shall be reduced by [***] of such Third Party Payments, subject to the
limitations set forth in clause (d) of this Section 4.2.2.  If GENENTECH elects to take any such license
agreement as described herein without having first determined that it is
necessary (as determined by GENENTECH in good faith) in order to exploit the
license granted to it under Section 2.1 of this Agreement in any country, then
GENENTECH shall not be entitled to the offset under this clause (c). If
IMMUNOGEN in good faith disputes GENENTECH’s determination hereunder, the
Parties shall submit the matter promptly to IMMUNOGEN’S Chief Executive Officer
and a designated officer of GENENTECH with settlement authority.

(d)                                 Limitations
on Offsets.  The royalty offset in
Section 4.2.2(c) above is separate and cumulative to the royalty offset under
Section 4.2.2(b) above, but each is subject to the limitations set forth in
this Section 4.2.2(d) as follows.  No
royalty reductions under this Section 4.2.2, alone or in the aggregate, shall
reduce the royalty (if any) for any Licensed Product in any country payable
pursuant to Section 4.2.1 above  by more than
[***] percent ([***]%) of the royalties otherwise owed to IMMUNOGEN thereunder,
nor reduce such royalty for such Licensed Product in any such country to less
than [***] percent ([***]%) of Net Sales of such Licensed Product in such
country.

4.2.3                        [***] and [***].

(a)                                  Notwithstanding
anything set forth in [***] above, the [***] set forth therein shall apply, on
a [***] and [***] basis, to [***] of [***] or its [***], [***] or [***] in
[***] would, [***] for the [***] under this Agreement, [***] a [***] the [***]
(excluding any 

Portions
of this Exhibit were omitted and have been filed separately with the Secretary
of the Commission pursuant to the Company’s application requesting confidential
treatment under Rule 24b-2 of the Securities Exchange Act of 1934.

 24
 

[***] by [***] and
[***]).  Subject to the other terms of
this Agreement (except for Section 4.2.2 above, which shall not apply), on a
[***] and [***] where and as of when the [***] under Section 4.2.1 [***] as a
[***] of this Section 4.2.3, GENENTECH shall [***] to IMMUNOGEN a [***] to
[***][***] ([***]%) of [***] of [***] by [***] and/or its [***] in [***].

(b)                                 [***].  Notwithstanding anything set forth in [***]
above, the [***] set forth in [***] above shall no longer apply, on a [***]
basis, on and after the [***] on which any [***] to [***] and [***] in a [***]
any [***].  Subject to the other terms of
this Agreement (except for [***], which shall not apply), on a [***] basis
where the [***] under [***] do not apply as a result of this [***],  [***] on the [***] of such [***] of [***] in
such [***] shall [***] and [***] to [***] a [***] equal to [***] percent ([***]%)
of [***] of all [***] by [***] and/or its [***] in [***]; provided, however,
that if the [***] is [***] from the [***] in [***], then this [***] shall no
longer apply and [***] shall [***] the [***] set forth in [***] on a [***]
basis [***] on the [***] of [***].

4.2.4                        Combination Products.  In determining Net Sales of any Combination
Products under this Agreement, Net Sales shall first be calculated in
accordance with the definition of “Net Sales” above, then multiplied by the
percentage value of the Licensed Product contained in the Combination Product,
such percentage value being the quotient obtained by dividing the current
market price of the Licensed Product by the sum of the separate current market
price of the Licensed Product and other ingredients which are therapeutically
active contained in the Combination Product. 
The current market price of each therapeutically active ingredient and
of the Licensed Product shall be for a quantity comparable to that contained in
the Combination Product and of the same class, purity and potency.  When no current market price is available for
any therapeutically active ingredient or for the Licensed Product, GENENTECH
shall calculate in good faith a hypothetical market price with respect to the
Combination Product, allocating the same proportions of costs, overhead and
profit as are then allocated to all similar substances then being made and
marketed by GENENTECH and having an ascertainable market price; provided,
however, that if IMMUNOGEN in good faith disputes GENENTECH’s
calculation, the Parties shall submit the matter promptly to IMMUNOGEN’S Chief
Executive Officer and a designated officer of GENENTECH with settlement
authority.

Portions
of this Exhibit were omitted and have been filed separately with the Secretary
of the Commission pursuant to the Company’s application requesting confidential
treatment under Rule 24b-2 of the Securities Exchange Act of 1934.

 25
 

4.3                                 One Royalty.  Only one royalty, calculated at the highest
applicable royalty rate under this Section 4, shall be payable to IMMUNOGEN hereunder
for each sale of a Licensed Product.

4.4                                 Royalty Term. GENENTECH shall pay
royalties with respect to each Licensed Product on a country-by-country and
Licensed Product-by-Licensed Product basis until the later of (a) ten (10)
years from the First Commercial Sale of such Licensed Product in such country
and (b) the expiration of the last to expire Valid Claim of the Licensed Patent
Rights covering the Licensed Product in such country.   Following such royalty term, GENENTECH shall
have a fully paid-up, irrevocable, freely transferable and sublicensable
license in such country under the relevant Licensed Patent Rights and Licensed
Technology, to Develop, have Developed, make, have made, use, have used, sell,
have sold, offer for sale, import and have imported such Licensed Product in
such country.

4.5                                 Payment Terms.

(a)                                  Payment
of Milestones; Payment of Royalties; Royalty Reports.  All [***] Milestone payments shall be made
within [***] days after the first achievement of each of the [***] Milestones
described above.  All [***] Milestones
payments shall be paid no later than the [***] of the [***] of the [***]
following the [***] in which the applicable [***] Milestone is achieved,
including in any circumstance in which [***] Milestones are achieved in the
[***].  Subject to the other terms of
this Agreement (including Section 4.1 above), GENENTECH shall make any
milestone payments owed to IMMUNOGEN hereunder in United States Dollars, using
the wire transfer provisions of this Section 4.4.  Subject to the other terms of this Agreement
(including Sections 4.2, 4.3 and 4.4 above), GENENTECH shall make any royalty
payments owed to IMMUNOGEN in United States Dollars, quarterly within [***]
days following the end of each calendar quarter for which such royalties are
deemed to occur (as provided in the next sentence), using the wire transfer
provisions of this Section 4.5.  For
purposes of determining when a sale of any Licensed Product occurs under this
Agreement, the sale shall be deemed to occur on the earlier of (i) the date the
Licensed Product is [***] or (ii) the date of the [***] the [***] of the
Licensed Product.  Each royalty payment
shall be accompanied by a report for each country in the Territory in which
sales of Licensed Products occurred in the calendar quarter covered by such
statement, specifying:  the gross sales
(if available) and Net Sales in each country’s currency; the applicable royalty
rate under this Agreement; the royalties payable in 

Portions
of this Exhibit were omitted and have been filed separately with the Secretary
of the Commission pursuant to the Company’s application requesting confidential
treatment under Rule 24b-2 of the Securities Exchange Act of 1934.

 26
 

each country’s
currency, including an accounting of deductions taken in the calculation of Net
Sales; the applicable exchange rate to convert from each country’s currency to
United States Dollars under this Section 4.5; and the royalties payable in
United States Dollars.

(b)                                 Foreign
Currency Exchange.  All royalties
shall be payable in full in the United States in United States Dollars,
regardless of the countries in which sales are made. For the purpose of
computing Net Sales for Licensed Products sold in any currency other than
United States Dollars, the quarterly royalty payment will be calculated as
follows:

(A/B) x C = United States Dollars royalty payment on
foreign current sales, where

A = foreign current “Net Sales” (as defined above) per
quarter;

B = foreign exchange conversion rate, expressed in
local currency per United States Dollar (using as the applicable foreign
exchange rate the average of the rate published in the [***] of the [***], for
the [***] of the calendar quarter); and

C = the royalty
rate applicable to such Net Sales under this Agreement.

(c)                                  Tax
Withholding; Restrictions on Payment.   All payments hereunder shall be made free and
clear of any taxes, duties, levies, fees or charges, except for withholding
taxes (to the extent applicable). 
GENENTECH shall make any applicable withholding payments due on behalf
of IMMUNOGEN and shall promptly provide IMMUNOGEN with written documentation of
any such payment sufficient to satisfy the requirements of the United States
Internal Revenue Service relating to an application by IMMUNOGEN for a foreign
tax credit for such payment.  If by law,
regulations or fiscal policy of a particular country in the Territory,
remittance of royalties in United States Dollars is restricted or forbidden,
written notice thereof shall promptly be given to IMMUNOGEN, and payment of the
royalty shall be made by the deposit thereof in local currency to the credit of
IMMUNOGEN in a recognized banking institution designated by IMMUNOGEN by
written notice to GENENTECH.  When in any
country in the Territory the law or regulations prohibit both the transmittal
and the deposit of royalties on sales in such country, royalty payments shall
be suspended for as long a such prohibition is in effect and as soon as such
prohibition ceases to be in effect, all royalties that GENENTECH would have
been under an obligation to transmit or deposit but for the prohibition shall
forthwith be deposited or transmitted, to the extent allowable.

Portions
of this Exhibit were omitted and have been filed separately with the Secretary
of the Commission pursuant to the Company’s application requesting confidential
treatment under Rule 24b-2 of the Securities Exchange Act of 1934.

 27
 

(d)                                 Wire
Transfers.  All payments hereunder
shall be made to IMMUNOGEN by bank wire transfer in immediately available funds
to the account designated by IMMUNOGEN by written notice to GENENTECH from time
to time.

4.6                                 Overdue Royalties.  Subject to the other terms of this Agreement,
royalties not paid within the time period set forth in this Section 4 shall
bear interest at a rate of [***] percent ([***]%) per month from the due date
until paid in full.

4.7                                 Records Retention; Review.

(a)                                  Royalties.  Commencing as of the date of First Commercial
Sale of the first Licensed Product, GENENTECH and its Sublicensees shall keep
for at least [***] years from the end of the calendar year to which they
pertain complete and accurate records of sales by GENENTECH or its
Sublicensees, as the case may be, of each Licensed Product, in sufficient
detail to allow the accuracy of the royalties to be confirmed.

(b)                                 Fully
Burdened Manufacturing Costs. 
Commencing as of the Effective Date, IMMUNOGEN shall keep for at least
[***] years following the end of the calendar year to which they pertain
complete and accurate records of all of IMMUNOGEN’s Fully Burdened
Manufacturing Costs for Preclinical Materials and Clinical Materials supplied
to GENENTECH (or its Sublicensee) hereunder, in sufficient detail to allow the
accuracy of the Fully Burdened Manufacturing Costs to be confirmed.

(c)                                  Review.  Subject to the other terms of this Section
4.7(c), at the request of either Party, upon at least [***] business days’
prior written notice from the requesting Party, and at the expense of the
requesting Party (except as otherwise provided herein), the other Party shall
permit an independent certified public accountant reasonably selected by the
requesting Party and reasonably acceptable to the other Party to inspect
(during regular business hours) the relevant records required to be maintained
by the other Party under this Section 4.7. 
At IMMUNOGEN’s request (which shall not be made more frequently than
once per year during the Term), the accountant shall be entitled to review the
then-preceding [***] years of GENENTECH’s records under this Section 4.7 for
purposes of verifying GENENTECH’s royalty calculations. At GENENTECH’s request
(which shall not be made more frequently than once per year during the Term),
the accountant shall be entitled to review the then-preceding [***] years of
IMMUNOGEN’s records under this Section 4.7 for purposes of verifying IMMUNOGEN’s
Fully Burdened Manufacturing Cost calculations. In every case the accountant 

Portions
of this Exhibit were omitted and have been filed separately with the Secretary
of the Commission pursuant to the Company’s application requesting confidential
treatment under Rule 24b-2 of the Securities Exchange Act of 1934.

 28
 

must have previously
entered into a confidentiality agreement with both Parties substantially
similar to the provisions of Section 4 and limiting the disclosure and use of
such information by such accountant to authorized representatives of the
Parties and the purposes germane to this Section 4.7.  Results of any such review shall be made
available to both Parties and shall be binding on both Parties.  Each Party agrees to treat the results of any
such accountant’s review of the other Party’s records under this Section 4.7 as
Confidential Information of the other Party subject to the terms of Section
5.  If any review reveals a deficiency in
the calculation of royalties resulting from any underpayment by GENENTECH,
GENENTECH shall promptly pay IMMUNOGEN the amount remaining to be paid (plus
interest thereon at the rate provided in Section 4.6 above), and if such
underpayment is by [***] percent ([***]%) or more, GENENTECH shall pay all
costs and expenses of the review.  If any
review reveals a deficiency in the calculation of Fully Burdened Manufacturing
Costs resulting from any overpayment by GENENTECH, IMMUNOGEN shall promptly
refund GENENTECH the amount of any such overpayment (plus interest thereon at
the rate provided in Section 4.6 above), and if such overpayment is by [***]
percent ([***]%) or more, IMMUNOGEN shall pay all costs and expenses of the
review.

5.  TREATMENT OF CONFIDENTIAL INFORMATION

5.1                                 Confidential Information.  During the Term, in the course of performance
of this Agreement, each Party may disclose to the other Party proprietary
technical and business information of the disclosing Party, including
techniques, data, inventions, practices, methods, knowledge, know-how, test
data and results (including from pre-clinical and/or human clinical testing),
analytical and quality control data, cost, sales, manufacturing, patent data
and any other information disclosed hereunder. 
Such information of the disclosing Party hereunder, if so identified in
writing by the disclosing Party to the receiving Party either pursuant to this
Section 5.1 or otherwise upon disclosure to the receiving Party, shall be
considered “Confidential Information” of the disclosing Party.  Each Party agrees that it will take the same
commercially reasonable steps to protect the confidentiality of other Party’s
Confidential Information as it takes to protect its own proprietary and
confidential information. For a period of [***] years after the receipt of any
such Confidential Information from the disclosing Party hereunder, subject to
the terms of this Section 5, the receiving Party shall keep confidential and
not disclose (by publication or otherwise) such Confidential Information of the
other Party, and shall not use, 

Portions
of this Exhibit were omitted and have been filed separately with the Secretary
of the Commission pursuant to the Company’s application requesting confidential
treatment under Rule 24b-2 of the Securities Exchange Act of 1934.

 29
 

publish or otherwise
disclose Confidential Information of the other Party for any purpose other than
those contemplated by this Agreement (including as reasonably necessary to
exercise any rights or perform any obligations under this Agreement). Notwithstanding
the foregoing, it is understood and agreed that the receiving Party’s
obligations of confidentiality and non-use herein shall not apply to the extent
that it can be established by competent written records that any such
information:

(a)                                  is,
at the time of disclosure by the disclosing Party hereunder, or thereafter
becomes, a part of the public domain or publicly known or available, other than
through any act or omission of the receiving Party in breach of its obligations
under this Section 5; or

(b)                                 was
known to the receiving Party at the time of disclosure to it by the disclosing
Party; or

(c)                                  is,
at the time of disclosure by the disclosing Party hereunder, or thereafter
becomes, known to the receiving Party from a source that had a lawful right to
disclose such information to others; or

(d)                                 was
independently developed by the receiving Party without use or reference to any
Confidential Information of the disclosing Party.

5.2                                 Permitted Disclosures; Publications.

(a)                                  Permitted
Disclosures.  Each Party shall be
entitled to disclose Confidential Information of the other Party to employees
of the receiving Party, provided that such employees are already bound by
obligations of confidentiality to their employer, and also to Affiliates,
consultants, agents and Third Parties for any purpose provided for in this
Agreement, provided that any such Affiliate, consultant, agent or other Third
Party has first agreed in writing to confidentiality restrictions and
obligations at least as protective as this Section 5, in each case for any
purpose contemplated by this Agreement (including as reasonably necessary to
exercise any rights or perform any obligations under this Agreement).

(b)                                 Review
of Publications.  Each Party shall
consult with the other Party prior to the submission of any manuscript for
publication if the publication will contain any Confidential Information of the
other Party, unless the applicable laws and regulations prohibit such
consultation.  Such consultation shall
include providing a copy of the proposed manuscript to the other Party at least
[***] days prior to the proposed date of submission to a publisher, 

Portions
of this Exhibit were omitted and have been filed separately with the Secretary
of the Commission pursuant to the Company’s application requesting confidential
treatment under Rule 24b-2 of the Securities Exchange Act of 1934.

 30
 

incorporating
appropriate changes proposed by the other Party regarding its Confidential
Information into the manuscript submission and deleting all Confidential
Information of the other Party as it may request; provided, however,
that the other Party’s review hereunder shall be deemed completed at the end of
such [***]-day period.

(c)                                  Other
Permitted Disclosures. 
Notwithstanding the foregoing, Confidential Information of either Party
may be disclosed by the other Party to the extent such disclosure is reasonably
necessary for filing or prosecuting patent applications or maintaining patents,
prosecuting or defending litigation, enforcing rights and/or obligations under
this Agreement, complying with applicable laws, regulations or court order or
conducting pre-clinical or human clinical testing of Licensed Products; provided,
that, if a Party is required by applicable law, regulation or court
order to make such disclosure of the other Party’s Confidential Information,
[***] of such other Party’s Confidential Information required to be disclosed.

5.3                                 Use of Names; Press  Releases.

(a)                                  Use
of Names.  A Party may not use the
name of the other Party (or any trademarks or tradenames of the other Party) in
any press release or any other publicity or advertising without the prior
written consent of the other Party.

(b)                                 Press
Releases.  Except as provided in
Sections 5.1 and 5.2 above, a Party may not issue a press release or otherwise
publicize or disclose any information related to this Agreement or the terms or
conditions hereof, without the prior written consent of the other Party.  Once any written text is approved for disclosure
by both Parties as provided herein, either Party may make subsequent or
repeated public disclosures of the contents thereof [***] the [***] of the
other Party, so long as such subsequent disclosures continue to be correct and
presented in appropriate context. 
Nothing in the foregoing, however, shall prohibit a Party from making
such disclosures regarding this Agreement or the terms thereof to the extent
deemed necessary under applicable federal or state securities laws or any rule
or regulation of any nationally recognized securities exchange, subject to the
terms of Section 5.2 above regarding disclosures required to comply with
applicable laws, regulations or court order.

5.4                                 Integration;
Survival.  As to the subject
matter of this Agreement, this Section 5 supersedes any confidential disclosure
agreements between the Parties.  Section
5 shall survive termination or expiration of this Agreement.

Portions
of this Exhibit were omitted and have been filed separately with the Secretary
of the Commission pursuant to the Company’s application requesting confidential
treatment under Rule 24b-2 of the Securities Exchange Act of 1934.

 31
 

6. 
PROVISIONS CONCERNING THE FILING, PROSECUTION AND

MAINTENANCE OF PATENT RIGHTS

6.1                                 Ownership of Intellectual Property.

(a)                                  Sole
Inventions.  IMMUNOGEN shall own all
inventions (whether or not patentable) made during the course of and pursuant
to activities carried out under this Agreement solely by employees of or agents
or others obligated to assign inventions to IMMUNOGEN. GENENTECH shall own all
inventions (whether or not patentable) made during the course of and pursuant
to activities carried out under this Agreement solely by employees of or agents
or others obligated to assign inventions to GENENTECH.  The Party solely owning any inventions
hereunder shall be the sole owner of any inventorship certificate(s), patent
application(s) and patent(s) thereon. All determinations of inventive
contribution shall be as determined by United States laws of inventorship.  Subject to the terms of Section 6.2 below
relating to IMMUNOGEN sole inventions, the Party solely owning an invention
hereunder will be solely responsible, at its own cost and expense and in its
sole discretion, for the filing, prosecution and maintenance of any
inventorship certificate(s), patent application(s) and patent(s) thereon.

(b)                                 Joint
Inventions.  Inventions made during
the course of and pursuant to activities carried out under this Agreement
jointly by employees of or agents of or others obligated to assign inventions
to IMMUNOGEN and GENENTECH shall be jointly owned by IMMUNOGEN and GENENTECH.
All determinations of inventive contribution shall be as determined by United
States laws of inventorship.  The Parties
shall also jointly own any inventorship certificate(s), patent application(s)
and patent(s) on any joint inventions hereunder. The terms of Section 6.2 below
relating to joint inventions shall apply to any inventorship certificate(s),
patent application(s) and patent(s) thereon.

(c)                                  Disclosure.  As regards any IMMUNOGEN sole or joint invention
hereunder or any GENENTECH joint inventions hereunder, each Party shall provide
to the other Party any invention disclosure made during the course of
performance of this Agreement and relating to activities carried out hereunder
within [***] days after such Party receives such disclosure from its employees,
agents or others obligated to assign inventions to such Party.

(d)                                 Other
Agreements.  An invention made during
the course of and pursuant to other agreements between the Parties, including
agreements related to process development or 

Portions
of this Exhibit were omitted and have been filed separately with the Secretary
of the Commission pursuant to the Company’s application requesting confidential
treatment under Rule 24b-2 of the Securities Exchange Act of 1934.

 32
 

manufacturing,
will be considered to be made under that separate agreement and not under this
Agreement.

6.2                                 Patent Filing, Prosecution and Maintenance.

(a)                                  Sole
IMMUNOGEN Inventions.  Subject to the other terms of this
Section 6.2(a) and Section 6.2(b), IMMUNOGEN shall have the right to prepare,
file, prosecute, obtain and maintain, at its sole cost and expense, all
Licensed Patent Rights. IMMUNOGEN agrees that with respect to such Licensed
Patent Rights licensed exclusively to GENENTECH hereunder, (i) any such
preparation, filing, prosecution and maintenance shall be conducted with
commercially reasonable diligence by IMMUNOGEN, using patent counsel selected
by IMMUNOGEN and reasonably acceptable to GENENTECH. In any case IMMUNOGEN (i)
will provide GENENTECH with a copy of any proposed patent application covering
any such Licensed Patent Rights for review and comment reasonably in advance of
filing (which shall under no circumstances be in excess of [***] days), and
(ii) will keep GENENTECH reasonably informed of the status of such filing,
prosecution and maintenance, including, without limitation, (A) by providing
GENENTECH with copies of all communications received from or filed in patent
office(s) with respect to such filing, and (B) by providing GENENTECH, a
reasonable time prior to taking or failing to take any action that would affect
the scope or validity of any such of any such filing (including the
substantially narrowing, cancellation or abandonment of any claim(s) without
retaining the right to pursue such subject matter in a separate application, or
the failure to file or perfect the filing of any claim(s) in any country), with
prior written notice of such proposed action or inaction so that GENENTECH has
a reasonable opportunity to review and comment. Any application for extension
of Licensed Patent Rights in the Territory due to delays in regulatory review
with respect to any Licensed Product shall be filed only upon mutual written
agreement of the Parties.  If IMMUNOGEN
fails to undertake the filing(s) of any patent application with respect to any
invention under such Licensed Patent Rights within [***] days after receipt of
written notice from GENENTECH that GENENTECH believes filing of such an
application by IMMUNOGEN is appropriate, GENENTECH may undertake such filing(s)
at its own expense, in which case IMMUNOGEN will assign all of its rights to
such invention to GENENTECH and any subsequently issued patent thereon will be
owned solely by GENENTECH.

Portions
of this Exhibit were omitted and have been filed separately with the Secretary
of the Commission pursuant to the Company’s application requesting confidential
treatment under Rule 24b-2 of the Securities Exchange Act of 1934.

 33
 

(b)                                 Joint
Inventions. As regards any joint invention by the Parties hereunder, the
Party from whom the majority of the data underlying any such joint invention
arose (the “controlling Party”) will have the first right, but not the
obligation, to undertake filing(s), prosecution and maintenance of inventorship
certificate(s), patent application(s) and patent(s) thereon.  In connection with any such filing(s), the
filing Party will use patent counsel mutually acceptable to each Party (in its
reasonable determination) and the Parties will, prior to filing of the patent
application, agree on mutually acceptable sharing of the costs and expenses of
such filing(s), prosecution and maintenance. 
In any case the filing Party (i) will provide the non-controlling Party
with a copy of any such proposed patent application for review and comment
reasonably in advance of filing, and (ii) will keep the non-controlling Party
reasonably informed of the status of such filing, prosecution and maintenance,
including, without limitation, (A) by providing the non-controlling Party with
copies of all communications received from or filed in patent office(s) with
respect to such filing, and (B) by providing the non-controlling Party, a
reasonable time prior to taking or failing to take any action that would affect
the scope or validity of any such filing (including the substantially
narrowing, cancellation or abandonment of any claim(s) without retaining the
right to pursue such subject matter in a separate application, or the failure
to file or perfect the filing of any claim(s) in any country), with prior
written notice of such proposed action or inaction so that the non-controlling
Party has a reasonable opportunity to review and comment. If the Party from
whom the majority of the data underlying any such joint invention fails to undertake
the filing(s) of any such patent application with respect to any such invention
within [***] days after receipt of written notice from the other Party that the
other Party believes filing(s) of such an application by such Party is
appropriate, such other Party may undertake such filing(s) at its own expense,
in which case the non-filing Party will assign all of its rights to such joint
invention to the filing Party and any subsequently issued patent thereon will
be owned solely by the filing Party. 
Either Party may assign its rights hereunder to any jointly owned
invention, inventorship certificate, patent application or patent to the other
Party, who will then have the right, in its discretion, to assume the filing,
prosecution and/or maintenance thereof as the sole owner thereof and at its
sole cost and expense.

6.3                                 Notice of Infringement.  If, during the Term of this Agreement, either
Party learns of any actual, alleged or threatened infringement by a Third Party
of any Licensed Patent 

Portions
of this Exhibit were omitted and have been filed separately with the Secretary
of the Commission pursuant to the Company’s application requesting confidential
treatment under Rule 24b-2 of the Securities Exchange Act of 1934.

 34
 

Rights under this
Agreement, such Party shall promptly notify the other Party and shall provide
such other Party with available evidence of such infringement.

6.4                                 Infringement of Patent Rights.

(a)                                  Sole
IMMUNOGEN Inventions.  IMMUNOGEN
shall have the first right (but not the obligation), at its own expense, to
bring suit (or take other appropriate legal action) against any actual, alleged
or threatened infringement of the Licensed Patent Rights solely owned by
IMMUNOGEN under this Agreement, with legal counsel of its own choice.  GENENTECH shall have the right, at its own
expense, to be represented in any such action by IMMUNOGEN by counsel of
GENENTECH’s own choice; provided, however, that under no
circumstances shall the foregoing affect the right of IMMUNOGEN to control the
suit as described in the first sentence of this Section 6.4(a).  If IMMUNOGEN does not file any action or
proceeding against such infringement within [***] days after the later of (i)
IMMUNOGEN’s notice to GENENTECH under Section 6.3 above, (ii) GENENTECH’s
notice to IMMUNOGEN under Section 6.3 above, or (iii) a written request from
GENENTECH to take action with respect to such infringement, then GENENTECH
shall have the right (but not the obligation), at its own expense, to bring
suit (or take other appropriate legal action) against such actual, alleged or
threatened infringement, with legal counsel of its own choice. IMMUNOGEN shall
have the right, at its own expense, to be represented in any such action by
GENENTECH by counsel of IMMUNOGEN’s own choice. 
Any damages, monetary awards or other amounts recovered, whether by
judgment or settlement, pursuant to any suit, proceeding or other legal action
taken under this Section 6.4(a), shall first be applied to reimburse the costs
and expenses (including attorneys’ fees) of the Party bringing such suit or
proceeding or taking such other legal action, then to the costs and expenses
(including attorneys’ fees), if any, of the other Party.  Any amounts remaining shall be allocated as
follows: (A) if GENENTECH is the Party bringing such suit or proceeding or
taking such other legal action, [***] percent ([***]%) to GENENTECH and [***]
percent ([***]%) to IMMUNOGEN,  (B) if
IMMUNOGEN is the Party bringing such suit or proceeding or taking such other
legal action, [***] percent ([***]%) to IMMUNOGEN and (C) if the suit is
brought jointly, [***] percent ([***]%) to each Party.  If a Party brings any such action or
proceeding hereunder, the other Party agrees to be joined as party plaintiff if
necessary to prosecute such action or proceeding, and to give the Party
bringing such action or proceeding reasonable assistance and authority to file
and prosecute the suit; provided, however, 

Portions
of this Exhibit were omitted and have been filed separately with the Secretary
of the Commission pursuant to the Company’s application requesting confidential
treatment under Rule 24b-2 of the Securities Exchange Act of 1934.

 35
 

that neither Party
shall be required to transfer any right, title or interest in or to any
property to the other Party or any Third Party to confer standing on a Party
hereunder.

(b)                               Infringement
of Joint Inventions.  As to the any
actual, alleged or threatened infringement of any Patent Rights jointly owned
by IMMUNOGEN and GENENTECH under this Agreement, including actions against any
alleged infringer, the Parties hereto will consult with each other in good
faith regarding the best manner in which to proceed.  The Parties agree as a basic principle that
in the case of such actions against infringers, the expenses incurred and
damages awarded shall be for the account of the Party or Parties who take such
actions to the extent of their financial participation therein.

6.5                                 Third Party Patents.  If any Third Party claims that a patent it
owns or controls claims any aspect of a Licensed Product or its manufacture,
use or sale, the Party with notice of such claim shall notify the other Party
promptly, and the Parties shall as soon as practicable thereafter discuss in
good faith regarding the best response.

6.6                                 Trademarks.  All Licensed Products shall be sold under one
(1) or more trademarks and tradenames selected and owned by GENENTECH (or its
Sublicensee) in the Territory.  GENENTECH
(or its Sublicensee) shall control the preparation, prosecution and maintenance
of applications related to all such trademarks and tradenames in the Territory,
at its sole cost and expense and at its sole discretion.  IMMUNOGEN shall notify GENENTECH promptly
upon learning of any actual, alleged or threatened infringement of a trademark
or tradename applicable to a Licensed Product in the Territory, or of any
unfair trade practices, trade dress imitation, passing off of counterfeit
goods, or like offenses in the Territory. 
All of the costs, expenses and legal fees in bringing, maintaining and
prosecuting any action to maintain, protect or defend any owned by GENENTECH
(or its Sublicensee) hereunder, and any damages or other recovery, shall be
GENENTECH’s (or its Sublicensee’s) sole responsibility, and taken in its sole
discretion.

6.7                                 Integration; Survival.  This Section 6 supersedes any provisions to
the contrary in the HER2 License Agreement and that certain [***] Process
Development Agreement by and between the Parties dated as of [***].  This Section 6 shall survive termination or
expiration of this Agreement.

Portions
of this Exhibit were omitted and have been filed separately with the Secretary
of the Commission pursuant to the Company’s application requesting confidential
treatment under Rule 24b-2 of the Securities Exchange Act of 1934.

 36
 

7.  TERM AND
TERMINATION

7.1                                 Term; Expiration. The term of this
Agreement (“Term”) shall expire upon the
expiration of the final royalty payment obligation under Section 4.4
above.  Upon such expiration of the Term
of this Agreement, GENENTECH shall have a fully paid-up, irrevocable, freely
transferable and sublicensable license in the Territory under the Licensed
Patent Rights and Licensed Technology, to Develop, have Developed, make, have
made, use, have used, sell, have sold, offer for sale, import and have imported
any and all Licensed Products in the Territory.

7.2.                              Termination.  Subject to the other terms of this Agreement:

(a)                                  Breach.
A Party may terminate this Agreement and the licenses granted herein, effective
upon written notice to the other Party, upon any breach by the other Party of
any material obligation or condition of this Agreement, which material breach
remains uncured [***] ([***]) days after the non-breaching Party gives a first
written notice to the other Party describing such breach in reasonable detail; provided,
however, that in the event of a [***] by [***] under this Agreement, the
[***] shall be [***] (in lieu of [***]) but the other terms of this Section
7.2(a) shall apply to termination in connection with any such payment
breach.  Notwithstanding anything set
forth herein, if the asserted material breach is cured or shown to be non-existent
within the applicable cure period, the first notice of breach hereunder shall
be deemed automatically withdrawn and of no effect.

(b)                                 Bankruptcy.
A Party may terminate this Agreement, effective on written notice to the other
Party, in the event the other Party shall have become insolvent or bankrupt, or
shall have made an assignment for the benefit of its creditors, or there shall
have been appointed a trustee or receiver of the other Party or for all or a
substantial part of its property, or any case or proceeding shall have been
commenced or other action taken by or against the other Party in bankruptcy or
seeking reorganization, liquidation, dissolution, winding-up, arrangement,
composition or readjustment of its debts or any other relief under any
bankruptcy, insolvency, reorganization or other similar act or law of any
jurisdiction now or hereafter in effect, or there shall have been issued a warrant
of attachment, execution, distraint or similar process against any substantial
part of the property of the other Party, and any such foregoing events shall
have continued for [***] days undismissed, unbonded and undischarged.  Furthermore, all rights and licenses granted
under this Agreement are, and shall be deemed to be, for purposes of Section
365(n) of the United States Bankruptcy Code, licenses of rights to “intellectual
property” as 

Portions
of this Exhibit were omitted and have been filed separately with the Secretary
of the Commission pursuant to the Company’s application requesting confidential
treatment under Rule 24b-2 of the Securities Exchange Act of 1934.

 37
 

defined under
Section 101(56) of the United States Bankruptcy Code.  The Parties agree that in the event of the
commencement of a bankruptcy proceeding by or against one Party hereunder under
the United States Bankruptcy Code, the other Party shall be entitled to
complete access to any such intellectual property, and all embodiments of such
intellectual property, pertaining to the rights granted in the licenses
hereunder of the Party by or against whom a bankruptcy proceeding has been
commenced, subject, however, to payment of the milestone amounts and royalties
set forth in this Agreement through the effective date of any termination
hereunder.

(c)                                  Unilateral
Termination by GENENTECH.  GENENTECH, in its sole discretion, at any
time may terminate this Agreement, and the rights and obligations hereunder, or
may remove any Licensed Product and the licenses related thereto from operation
of this Agreement, in any case effective [***] days after written notice
thereof to IMMUNOGEN.  In the event of
any termination under this Section 7.2(c) only as to a Licensed Product, the
consequences set forth in Section 7.3 below relating to termination of the
Agreement under this Section 7.2(c) shall apply only with respect to such
terminated Licensed Product, and this Agreement and the rights and obligations
hereunder shall continue in full force and effect as to any and all other
Licensed Products.

7.3                                 Effects of Termination.  Upon any termination of this Agreement by
IMMUNOGEN under Section 7.2(a) or by GENENTECH under Section 7.2(c), as of the
effective date of such termination, all relevant licenses and sublicenses
granted by IMMUNOGEN to GENENTECH hereunder shall terminate automatically.  Notwithstanding the foregoing, (a) no such
termination of this Agreement shall be construed as a termination of any valid
sublicense of any Sublicensee hereunder, and thereafter each such Sublicensee
shall be considered a direct licensee of IMMUNOGEN, provided that (i)
such Sublicensee is then in full compliance with all terms and conditions of
its sublicense, (ii) all accrued payments obligations to IMMUNOGEN have been
paid, and (iii) such sublicensee agrees at least ten (10) days prior to the
effective date of such termination to assume all obligations of GENENTECH under
this Agreement, and (b) GENENTECH and its Sublicensees shall have the right,
for [***] months or such longer time period (if any) on which the Parties
mutually agree in writing, to sell or otherwise dispose of all Licensed
Products then on hand, with royalties to be paid to IMMUNOGEN on all Net Sales
of such Licensed Products as provided for in this Agreement.  Nothing set forth in this Section 7 or any
other provision of this Agreement shall entitle 

Portions
of this Exhibit were omitted and have been filed separately with the Secretary
of the Commission pursuant to the Company’s application requesting confidential
treatment under Rule 24b-2 of the Securities Exchange Act of 1934.

 38
 

IMMUNOGEN to any
ownership interest in, or to any license under or other rights with respect to
(including any rights to use or request any transfer to IMMUNOGEN or any Third Party),
any Confidential Information of GENENTECH or any Technology or Patent Rights
solely owned by GENENTECH under this Agreement.

7.4                                 Effects of Termination For IMMUNOGEN Breach.  Upon any termination of this Agreement by
GENENTECH under Section 7.2(a), as of the effective date of such termination,
GENENTECH thereafter automatically shall have a fully sublicensable and
transferable, fully paid up (subject to the remainder of this Section 7.4),
exclusive license in the Territory under the Licensed Patent Rights and
Licensed Technology, to Develop, have Developed, make, have made, use, have
used, sell, have sold, offer for sale, import and have imported any and all
Licensed Products in the Territory, provided that GENENTECH shall pay,
for the remainder of the royalty term under Section 4.4 above, [***] of any
payments including milestones or royalties it would [***] to IMMUNOGEN under
this Agreement, a [***] equal to [***] of the [***] that would [***] with
respect to the Licensed Product under Sections 4.2.1, 4.2.2, 4.2.3 and 4.2.4 of
this Agreement.

7.5                                 Remedies.  Except as otherwise expressly set forth in
this Agreement, the termination provisions of this Section 7 are in addition to
any other relief and remedies available to either Party at law.

7.6                                 Surviving Provisions.  Notwithstanding any provision herein to the
contrary, the rights and obligations of the Parties set forth in Sections 4.7,
5, 6, 7.3, 7.4, 7.5, 8, 9, 10 and this Section 7.6, as well as any rights or
obligations otherwise accrued hereunder (including any accrued payment
obligations), shall survive the expiration or termination of the Term of this
Agreement. Without limiting the generality of the foregoing, GENENTECH shall
have no obligation to make any milestone or royalty payment to IMMUNOGEN that
has not accrued prior to the effective date of any termination of this
Agreement, but shall remain liable for all such payment obligations accruing
prior to the effective date of such termination.

8. 
REPRESENTATIONS AND WARRANTIES

8.1                                 IMMUNOGEN Representations.  IMMUNOGEN represents and warrants to
GENENTECH that:  (a) the execution and
delivery of this Agreement and the performance of the transactions contemplated
hereby have been duly authorized by all appropriate IMMUNOGEN 

Portions
of this Exhibit were omitted and have been filed separately with the Secretary
of the Commission pursuant to the Company’s application requesting confidential
treatment under Rule 24b-2 of the Securities Exchange Act of 1934.

 39
 

corporate action;
(b) this Agreement is a legal and valid obligation binding upon IMMUNOGEN and
enforceable in accordance with its terms, and the execution, delivery and
performance of this Agreement by the Parties does not conflict with any
agreement, instrument or understanding to which IMMUNOGEN is a party or by
which it is bound; (c) IMMUNOGEN has the full right and legal capacity to grant
the licenses and rights to GENENTECH pursuant to Section 2 above without
violating the rights of any Third Party; and (d) to IMMUNOGEN’s knowledge, no
Patent Rights within the Licensed Patent Rights are invalid or unenforceable or
would infringe Patent Rights of Third Parties, and as of the Effective Date no
patents within the Licensed Patent Rights are expired.

8.2                                 GENENTECH Representations.  GENENTECH represents and warrants to
IMMUNOGEN that:  (a) the execution and
delivery of this Agreement and the performance of the transactions contemplated
hereby have been duly authorized by all appropriate GENENTECH corporate action;
and (b) this Agreement is a legal and valid obligation binding upon GENENTECH
and enforceable in accordance with its terms, and the execution, delivery and
performance of this Agreement by the Parties does not conflict with any
agreement, instrument or understanding to which GENENTECH is a party or by
which it is bound.

8.3                                 No Warranties.

(a)                                  Nothing
in this Agreement is or shall be construed as:

(i)                                     a
warranty or representation by IMMUNOGEN as to the validity or scope of any
patent application or patent within the Licensed Patent Rights;

(ii)                                  a
warranty or representation that anything made, used, sold or otherwise disposed
of under any license granted in this Agreement is or will be free from
infringement of patents, copyrights, and other rights of third parties.

(b)                                 Except
as expressly set forth in this Agreement, NEITHER PARTY MAKES ANY
REPRESENTATIONS OR EXTENDS ANY WARRANTIES OF ANY KIND, EITHER EXPRESS OR
IMPLIED.  THERE ARE NO EXPRESS OR IMPLIED
WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, THAT ANY
LICENSED PRODUCT WILL BE SUCCESSFULLY DEVELOPED OR MARKETED, OR THAT THE
DEVELOPMENT, MANUFACTURE, SALE, IMPORTATION OR USE OF THE LICENSED PRODUCT(S)
WILL NOT INFRINGE ANY PATENT, 

Portions
of this Exhibit were omitted and have been filed separately with the Secretary of
the Commission pursuant to the Company’s application requesting confidential
treatment under Rule 24b-2 of the Securities Exchange Act of 1934.

 40
 

COPYRIGHT,
TRADEMARK, OR OTHER RIGHTS, OR ANY OTHER EXPRESS OR IMPLIED WARRANTIES.

8.4                                 Survival. Section 8 shall survive
termination or expiration of this Agreement.

9. 
INDEMNIFICATION; LIABILITY

9.1                                 Indemnification.

(a)                                  GENENTECH
Indemnity.  Subject to Section 9.1(b)
below and the remainder of this Section 9, GENENTECH shall indemnify, defend
and hold harmless IMMUNOGEN, its Affiliates and their respective directors,
officers, employees, and agents and their respective successors, heirs and
assigns (the “Indemnitees”), from and
against any liability, damage, loss or expense (including reasonable attorneys’
fees and expenses of litigation) incurred by or imposed upon such Indemnitees,
or any of them, in connection with any Third Party claims, suits, actions,
demands or judgments, including, without limitation, personal injury and
product liability matters (but excluding any patent, trademark or tradename
infringement matters, which are governed by Section 6 above), that arise out of
or relate to (i) any actions or omissions of GENENTECH or any Sublicensee in
the development, testing, production, manufacture, supply, promotion, import,
sale or use by any person of any Licensed Product (or any component thereof)
manufactured or sold by GENENTECH or any Sublicensee under this Agreement, (ii)
any material breach of this Agreement by GENENTECH, or (iii) negligence or willful
misconduct on the part of GENENTECH, in any such case under this Section 9.1(a)
except to the extent of IMMUNOGEN’s responsibility therefor under Section
9.1(b) below.

(b)                                 IMMUNOGEN
Indemnity.  Subject to Section 9.1(a)
above and the remainder of this Section 9, IMMUNOGEN shall indemnify, defend
and hold harmless GENENTECH, its Affiliates and their respective directors,
officers, employees, and agents, and their respective successors, heirs and
assigns (also the “Indemnitees”),
from and against any liability, damage, loss or expense (including reasonable
attorneys’ fees and expenses of litigation) incurred by or imposed upon such
Indemnitees, or any of them, in connection with any Third Party claims, suits,
actions, demands or judgments, including, without limitation, personal injury
and product liability matters (but excluding any patent, trademark or tradename
infringement matters, which are governed by Section 6 above), that arise out of
or relate to (i) any actions or omissions of 
IMMUNOGEN or subcontractor of IMMUNOGEN in the 

Portions
of this Exhibit were omitted and have been filed separately with the Secretary
of the Commission pursuant to the Company’s application requesting confidential
treatment under Rule 24b-2 of the Securities Exchange Act of 1934.

 41
 

development,
testing, production, manufacture or supply of any Licensed Product (or any
component thereof) manufactured and supplied by IMMUNOGEN or any subcontractor
of IMMUNOGEN under this Agreement, (ii) any material breach of this Agreement by
IMMUNOGEN, or (iii) negligence or willful misconduct on the part of IMMUNOGEN,
in any such case under this Section 9.1(b) except to the extent of GENENTECH’s
responsibility therefor under Section 9.1(a) above.

9.2                                 Indemnification Procedures.  In the event that any Indemnitee is seeking
indemnification under Section 9.1 above from a Party (the “Indemnifying
Party”), the other Party shall notify the Indemnifying Party of
such claim with respect to such Indemnitee as soon as reasonably practicable
after the Indemnitee receives notice of the claim, and the Party (on behalf of
itself and such Indemnitee) shall permit the Indemnifying Party to assume
direction and control of the defense of the claim (including the right to
settle the claim solely for monetary consideration) and shall cooperate as
requested (at the expense of the Indemnifying Party) in the defense of the
claim.

9.3                                 Liability.  NOTWITHSTANDING ANYTHING ELSE IN THIS
AGREEMENT OR OTHERWISE, NEITHER PARTY WILL BE LIABLE WITH RESPECT TO ANY
SUBJECT MATTER OF THIS AGREEMENT UNDER ANY CONTRACT, NEGLIGENCE, STRICT
LIABILITY OR OTHER LEGAL OR EQUITABLE THEORY FOR (a) ANY INDIRECT, INCIDENTAL,
CONSEQUENTIAL OR PUNITIVE DAMAGES OR LOST PROFITS OR (b) COST OF PROCUREMENT OF
SUBSTITUTE GOODS, TECHNOLOGY OR SERVICES.

9.4                                 Survival. Section 9 shall survive
termination or expiration of this Agreement.

10. MISCELLANEOUS

10.1                           Entire Agreement; Amendments.  This is the entire Agreement between the
Parties with respect to the subject matter herein, and supersedes any prior
agreements, understandings, negotiations or correspondence between the Parties
respecting the subject matter hereof, whether written or verbal.  No modification or other amendment of this
Agreement shall be effective unless in writing and signed by a fully authorized
representative of each Party.

10.2                           Waiver.  The terms or conditions of this Agreement may
be waived only by a written instrument executed by a duly authorized
representative of the Party waiving compliance. 

Portions
of this Exhibit were omitted and have been filed separately with the Secretary
of the Commission pursuant to the Company’s application requesting confidential
treatment under Rule 24b-2 of the Securities Exchange Act of 1934.

 42
 

The failure of
either Party at any time or times to require performance of any provision
hereof shall in no manner affect its rights at a later time to enforce the
same.  No waiver by either Party of any
condition or term shall be deemed as a continuing waiver of such condition or
term or of another condition or term.

10.3                           Governing Law.  This Agreement will be construed, interpreted
and applied in accordance with the laws of the State of California applicable
to contracts entered into and to be performed entirely within the State of
California.

10.4                           Notices.  Any notices, requests, deliveries, approvals
or consents required or permitted to be given under this Agreement to GENENTECH
or IMMUNOGEN shall be in writing and shall be personally delivered or sent by
telecopy (with machine confirmation of transmission) or by overnight courier
providing evidence of receipt or certified mail, return receipt requested,
postage prepaid, in each case to the respective address specified below (or to
such address as may be specified in writing to the other Party hereto):

	
  If to IMMUNOGEN:

  	
   

  	
  ImmunoGen, Inc.

  
	
   

  	
   

  	
  128 Sidney Street

  
	
   

  	
   

  	
  Cambridge, MA 02139-4239

  
	
   

  	
   

  	
  Attn:   Chief
  Executive Officer

  
	
   

  	
   

  	
  Fax: (617) 995-2510

  
	
   

  	
   

  	
   

  
	
  with a copy to

  	
   

  	
  Mintz, Levin, Cohn, Ferris, Glovsky and Popeo, P.C.

  
	
   

  	
   

  	
  One Financial Center

  
	
   

  	
   

  	
  Boston, MA 02111

  
	
   

  	
   

  	
  Attn: [***], Esq.

  
	
   

  	
   

  	
  (617) 542-2241

  
	
   

  	
   

  	
   

  
	
  If to GENENTECH:

  	
   

  	
  Genentech, Inc.

  
	
   

  	
   

  	
  1 DNA Way 94080

  
	
   

  	
   

  	
  South San Francisco, CA 94080

  
	
   

  	
   

  	
  Attn: Corporate Secretary

  
	
   

  	
   

  	
  Fax: (650) 467-9146

  

 

Such
notices shall be deemed to have been sufficiently given on:  (a) the date sent if delivered in person or
transmitted by telecopy, (b) the next business day after dispatch in the case
of overnight courier or (c) five (5) business days after deposit in the U.S.
mail in the case of certified mail.

Portions
of this Exhibit were omitted and have been filed separately with the Secretary
of the Commission pursuant to the Company’s application requesting confidential
treatment under Rule 24b-2 of the Securities Exchange Act of 1934.

 43
 

10.5                           No Implied Licenses.  Except as expressly set forth elsewhere in
this Agreement, neither Party grants to the other Party any right or license to
any of its intellectual property.

10.6                           Headings.  Section and subsection headings are inserted
for convenience of reference only and do not form part of this Agreement.

10.7                           Assignment.  This Agreement may not be assigned by either
Party without the consent of the other, except that each Party may, without
such consent, assign this Agreement and the rights, obligations and interests
of such Party, in whole or in part, to any of its Affiliates, to any purchaser
of all or substantially all of its assets in the line of business to which this
Agreement pertains or to any successor corporation resulting from any merger or
consolidation of such Party with or into such corporations.

10.8                           Force Majeure.  Neither Party shall be liable for failure of
or delay in performing obligations set forth in this Agreement, and neither
shall be deemed in breach of its obligations, if such failure or delay is due
to natural disasters or any causes beyond the reasonable control of such
Party.  In event of such force majeure,
the Party affected thereby shall use reasonable efforts to cure or overcome the
same and resume performance of its obligations hereunder.

10.9                           Construction.  The Parties hereto acknowledge and agree
that:  (a) each Party and its
counsel reviewed and negotiated the terms and provisions of this Agreement and
have contributed to its revision; (b) the rule of construction to the
effect that any ambiguities are resolved against the drafting Party shall not
be employed in the interpretation of this Agreement; and (c) the terms and
provisions of this Agreement shall be construed fairly as to each Party hereto
and not in a favor of or against any Party, regardless of which Party was
generally responsible for the preparation of this Agreement.

10.10                     Severability.  If any provision(s) of this Agreement are or
become invalid, are ruled illegal by any court of competent jurisdiction or are
deemed unenforceable under then current applicable law from time to time in
effect during the term hereof, it is the intention of the Parties that the
remainder of this Agreement shall not be affected thereby provided that a Party’s
rights under this Agreement are not materially affected.  The Parties hereto covenant and agree to
renegotiate any such term, covenant or application thereof in good faith in
order to provide a reasonably acceptable alternative to the term, covenant or
condition of this Agreement or the application thereof that is invalid, illegal
or unenforceable, it being the intent of the Parties that the basic purposes of
this Agreement are to be effectuated.

Portions
of this Exhibit were omitted and have been filed separately with the Secretary
of the Commission pursuant to the Company’s application requesting confidential
treatment under Rule 24b-2 of the Securities Exchange Act of 1934.

 44
 

10.11                     Status.           Nothing in this Agreement is intended or
shall be deemed to constitute a partner, agency, employer-employee, or joint
venture relationship between the Parties.

10.12                     Dispute Resolution.  The Parties recognize that a bona fide
dispute as to certain matters may from time to time arise during the term of
this Agreement relating to either Party’s rights and/or obligations hereunder
or otherwise relating to the validity, enforceability or performance of this
Agreement, including disputes relating to alleged breach or termination of this
Agreement but excluding any determination of the validity of the Parties’
patents (hereinafter, a “Dispute”).  In
the event of the occurrence of any such Dispute, the Parties pledge to attempt
to resolve it amicably.  Accordingly, if
any Dispute should arise, either Party may, by written notice to the other
Party, have such dispute referred to their respective senior officers
designated below (and to any designated officer of a GENENTECH Sublicensee, if
such Dispute involves such Sublicensee), for attempted resolution by good faith
negotiations commencing promptly after such notice is received; provided,
however, that if the subject matter of such Dispute is within the
purview of the Collaboration Committee, the Parties’ representatives on the
Collaboration Committee shall first attempt to resolve such Dispute before
referring it to the Parties’ senior officers hereunder.  Said designated senior officials of the
Parties are as follows:

For GENENTECH:    Designated
officer with settlement authority; and

For IMMUNOGEN:    Chief
Executive Officer.

In the event the
designated senior officials are not able to resolve such Dispute, the Parties
may seek to mediate their Dispute, on terms and with a mediator mutually
agreeable to the Parties, or may seek to arbitrate their Dispute, on mutually
agreed upon terms and conditions, but neither Party shall be required or
obligated to mediate or arbitrate and the dispute resolution provisions of this
Section 10.12 are in addition to any other relief and remedies available to
either Party at law or in equity.

10.13                     Further Assurances.  Each Party agrees to execute, acknowledge and
deliver such further instruments, and to do all other such acts, as may be
necessary or appropriate in order to carry out the purposes and intent of this
Agreement.

Portions
of this Exhibit were omitted and have been filed separately with the Secretary
of the Commission pursuant to the Company’s application requesting confidential
treatment under Rule 24b-2 of the Securities Exchange Act of 1934.

 45
 

10.14                     Counterparts.  This Agreement may be executed simultaneously
in one or more counterparts, each of which shall be deemed an original, but all
of which together shall constitute one and the same instrument.

Portions
of this Exhibit were omitted and have been filed separately with the Secretary
of the Commission pursuant to the Company’s application requesting confidential
treatment under Rule 24b-2 of the Securities Exchange Act of 1934.

[Remainder
of page intentionally left blank.]

 46
 

IN WITNESS
WHEREOF, the Parties have caused this Agreement to be executed by their duly
authorized representatives, effective as of the Effective Date set forth on the
first page hereof.

	
  GENENTECH, INC.

  	
   

  	
  IMMUNOGEN, INC.

  
	
   

  	
   

  	
   

  
	
   

  	
   

  	
   

  
	
  By:

  	
   

  	
   

  	
   

  	
  By:

  	
   

  	
   

  
	
   

  	
   

  	
   

  
	
  Title:

  	
   

  	
   

  	
   

  	
  Title:

  	
   

  	
   

  
	
   

  	
   

  	
   

  
	
  Date:

  	
   

  	
   

  	
   

  	
  Date:

  	
   

  	
   

  
										

 

Portions
of this Exhibit were omitted and have been filed separately with the Secretary
of the Commission pursuant to the Company’s application requesting confidential
treatment under Rule 24b-2 of the Securities Exchange Act of 1934.

 47

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