Exhibit 10.2

THIS EXHIBIT HAS BEEN REDACTED AND IS THE SUBJECT OF A CONFIDENTIAL TREATMENT
REQUEST.  REDACTED MATERIAL IS MARKED WITH [* * *] AND HAS BEEN FILED SEPARATELY
WITH THE SECURITIES AND EXCHANGE COMMISSION.

AMENDED AND RESTATED COLLABORATION, LICENSE AND OPTION AGREEMENT
by and between
ACCELERON PHARMA, INC.
and
CELGENE CORPORATION

           

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THIS EXHIBIT HAS BEEN REDACTED AND IS THE SUBJECT OF A CONFIDENTIAL TREATMENT
REQUEST.  REDACTED MATERIAL IS MARKED WITH [* * *] AND HAS BEEN FILED SEPARATELY
WITH THE SECURITIES AND EXCHANGE COMMISSION.

TABLE OF CONTENTS

 
 
 
 
Page
Article 1

 
DEFINITIONS
 
2

Article 2

 
COLLABORATION
 
21

2.1

 
Development
 
21

2.2

 
Records
 
22

2.3

 
Regulatory Matters
 
23

2.4

 
Manufacture and Supply
 
25

2.5

 
Commercialization Plan/Budget
 
28

2.6

 
Commercialization
 
28

2.7

 
Commercialization Activities in the Celgene Field
 
29

2.8

 
Third Parties
 
31

2.9

 
Information Sharing
 
32

2.10

 
ACE-536 Agreement
 
32

Article 3

 
COLLABORATION MANAGEMENT
 
33

3.1

 
Joint Development Committee
 
33

3.2

 
Joint Commercialization Committee
 
34

3.3

 
Joint Responsibilities of the Joint Development Committee and Joint
Commercialization Committee
 
37

3.4

 
Appointment of Subcommittees and Project Teams
 
37

3.5

 
Decision-Making
 
37

3.6

 
Dispute Resolution
 
38

3.7

 
Dissolution
 
38

3.8

 
Appointment of Joint Development Committee and Joint Commercialization Committee
Members
 
38

Article 4

 
LICENSES, GRANTS OF RIGHTS AND INTELLECTUAL PROPERTY OWNERSHIP
 
38

4.1

 
License Grants to Celgene
 
38

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4.2

 
License Grant to Acceleron
 
38

4.3

 
Retained Rights of Acceleron
 
39

4.4

 
Sublicenses
 
39

4.5

 
Right of Reference
 
40

4.6

 
Ownership of and Rights to Intellectual Property
 
41

4.7

 
Salk License
 
42

4.8

 
Right of First Negotiation
 
44

4.9

 
No Other Rights
 
45

Article 5

 
FINANCIAL PROVISIONS
 
45

5.1

 
Upfront Payments
 
45

5.2

 
ActRIIA Development Milestones
 
45

5.3

 
Option Compound Development Milestones
 
47

5.4

 
Ex-North American Sales Milestones
 
49

5.5

 
Sharing Costs
 
49

5.6

 
Royalties Payable for Celgene Field Net Sales
 
52

5.7

 
Royalties Payable for PH Field Net Sales
 
56

5.8

 
Payment Provisions Generally
 
59

Article 6

 
EXCLUSIVITY
 
62

6.1

 
Prohibitions
 
62

6.2

 
Third Party Acquisitions
 
64

6.3

 
Acquisitions of Third Parties
 
65

6.4

 
Termination of ACE-536 Agreement
 
66

Article 7

 
OPTION PROGRAM
 
66

7.1

 
Conduct of Option Compound Programs
 
66

7.2

 
Option Program Payments
 
67

7.3

 
Updates; Reports
 
67

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REQUEST.  REDACTED MATERIAL IS MARKED WITH [* * *] AND HAS BEEN FILED SEPARATELY
WITH THE SECURITIES AND EXCHANGE COMMISSION.

Article 8

 
INTELLECTUAL PROPERTY PROTECTION AND RELATED MATTERS
 
68

8.1

 
Salk Patent Rights
 
68

8.2

 
Prosecution of Patent Rights
 
68

8.3

 
Enforcement of Patent Rights
 
74

8.4

 
Claimed Infringement of Third Party Rights
 
76

8.5

 
Other Infringement Resolutions
 
77

8.6

 
Product Trademarks & Product Designation
 
77

8.7

 
Marking
 
78

8.8

 
Patent Term Extensions
 
78

Article 9

 
CONFIDENTIALITY
 
79

9.1

 
Confidential Information
 
79

9.2

 
Publication Review
 
80

9.3

 
Public Announcements and Use of Names
 
81

Article 10

 
TERM AND TERMINATION
 
82

10.1

 
Term
 
82

10.2

 
Termination for Cause
 
82

10.3

 
Termination for Convenience
 
84

10.4

 
Termination for Failure to Meet End Points
 
85

10.5

 
Other Effects of Termination
 
85

10.6

 
Sell-Down
 
89

10.7

 
Transfer of Records
 
90

10.8

 
Rights in Bankruptcy
 
90

10.9

 
Effect of Expiration or Termination; Survival
 
90

Article 11

 
REPRESENTATIONS AND WARRANTIES; INDEMNIFICATION
 
90

11.1

 
Mutual Representations and Warranties
 
90

11.2

 
Acceleron Representations, Warranties and Covenants
 
91

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WITH THE SECURITIES AND EXCHANGE COMMISSION.

11.3

 
Option Compound Representations and Warranties
 
93

11.4

 
Celgene Representations, Warranties and Covenants
 
93

11.5

 
Warranty Disclaimer
 
93

11.6

 
No Consequential Damages
 
93

11.7

 
Indemnification and Insurance
 
93

Article 12

 
MISCELLANEOUS PROVISIONS
 
96

12.1

 
Dispute Resolution; Governing Law
 
96

12.2

 
Assignment
 
96

12.3

 
Amendments
 
97

12.4

 
Notices
 
97

12.5

 
Force Majeure
 
97

12.6

 
Compliance with Applicable Laws
 
98

12.7

 
Independent Contractors
 
98

12.8

 
Further Assurances
 
98

12.9

 
No Strict Construction
 
98

12.10

 
Headings
 
98

12.11

 
No Implied Waivers; Rights Cumulative
 
98

12.12

 
Effect of Restatement; Entire Agreement
 
99

12.13

 
Severability
 
99

12.14

 
No Third Party Beneficiaries
 
99

12.15

 
Execution in Counterparts
 
99

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THIS EXHIBIT HAS BEEN REDACTED AND IS THE SUBJECT OF A CONFIDENTIAL TREATMENT
REQUEST.  REDACTED MATERIAL IS MARKED WITH [* * *] AND HAS BEEN FILED SEPARATELY
WITH THE SECURITIES AND EXCHANGE COMMISSION.

AMENDED AND RESTATED COLLABORATION, LICENSE
AND OPTION AGREEMENT
This Amended and Restated Collaboration, License and Option Agreement (this
“Agreement” and, as the context requires, this “Agreement” shall mean this
Agreement or the Amended Agreement) dated the 18th day of September, 2017 (the
“Amended and Restated Effective Date”) is by and between Acceleron Pharma, Inc.,
a Delaware corporation having its principal office at 149 Sidney Street,
Cambridge, MA 02139 (“Acceleron”) and Celgene Corporation, a Delaware
corporation having its principal office at 86 Morris Avenue, Summit, NJ 07901
(“Celgene”). Acceleron and Celgene may each be referred to herein individually
as a “Party” and collectively as the “Parties.”
INTRODUCTION
WHEREAS, the Parties entered into the Collaboration, License and Option
Agreement dated as of February 20, 2008 (the “Original Agreement”) and amended
the Original Agreement by entering into the First Amendment to the
Collaboration, License and Option Agreement dated as of August 2, 2011 (the
“First Amendment” and the Original Agreement as amended by the First Amendment,
the “Amended Agreement”);
WHEREAS, the Parties have been collaborating under the terms of the Amended
Agreement, in the investigation and development of certain protein-based product
candidates incorporating ActRIIA for the treatment, prevention, or modulation of
diseases and conditions in humans;
WHEREAS, Acceleron and Celgene, pursuant to the Amended Agreement, entered into
an option arrangement regarding rights to collaborate in the investigation and
development of certain product candidates incorporating antibodies targeting [*
* *], [* * *], and [* * *] for the treatment, prevention, or modulation of
diseases and conditions in humans; and
WHEREAS, Acceleron and Celgene wish to, under this Agreement, amend the terms of
the Amended Agreement to permit Acceleron to retain, subject to the terms and
conditions of this Agreement, exclusive rights to Develop and Commercialize
Sotatercept Licensed Compounds and Sotatercept Licensed Products in the PH Field
in the Territory under the terms and conditions set forth herein;
NOW, THEREFORE, in consideration of the mutual promises and covenants set forth
below and other good and valuable consideration, the receipt and sufficiency of
which is hereby acknowledged, the Parties hereby agree that the Amended
Agreement is hereby amended and restated in its entirety as follows:

1
 

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THIS EXHIBIT HAS BEEN REDACTED AND IS THE SUBJECT OF A CONFIDENTIAL TREATMENT
REQUEST.  REDACTED MATERIAL IS MARKED WITH [* * *] AND HAS BEEN FILED SEPARATELY
WITH THE SECURITIES AND EXCHANGE COMMISSION.

Article 1
DEFINITIONS

Except as otherwise explicitly specified to the contrary, (a) references to a
Section, Article, Exhibit or Schedule means a Section or Article of, or Schedule
or Exhibit to this Agreement, unless another agreement is specified, (b) the
word “including” will be construed as “including without limitation,” (c)
references to a particular statute or regulation include all rules and
regulations thereunder and any predecessor or successor statute, rules or
regulations, in each case, as amended or otherwise modified from time to time,
(d) words in the singular or plural form include the plural and singular form,
respectively, (e) words of any gender include each other gender, (f) “or” is
disjunctive but not necessarily exclusive, (g) the word “will” shall be
construed to have the same meaning and effect as the word “shall,” (h) whenever
this Agreement refers to a number of days, such number shall refer to calendar
days unless Business Days are specified, and (i) references to a particular
person include such person’s successors and assigns to the extent not prohibited
by this Agreement.
When used in this Agreement, each of the following terms shall have the meanings
set forth in this Article 1:
1.1    “Acceleron Collaboration IP” means any and all Collaboration IP created,
conceived or reduced to practice, and, in the case of patentable Collaboration
IP, Invented, solely by Acceleron, its Affiliates, agents or by Third Parties
acting on their behalf, while performing activities under this Agreement;
provided, however, that Acceleron Collaboration IP shall not include any
Collaboration IP that is Celgene Collaboration IP or Joint Collaboration IP.
1.2    “Acceleron Development Activities” means (a) all Development activities,
including preclinical pharmacology studies, preclinical safety studies, Phase 1
Clinical Trials, initial Phase 2A Clinical Trials, and formulation development
for Clinical Supply for such Clinical Trials, undertaken by Acceleron pursuant
to this Agreement for the purpose of obtaining Regulatory Approval within North
America and Europe and (b) and all PH Field Development Activities except for
those that are Celgene Development Activities.
1.3    “Acceleron Improvements” means any and all Improvements to the Acceleron
Technology or the Joint Technology created, conceived or reduced to practice,
and, in the case of patentable Improvements, Invented, solely by Acceleron, its
Affiliates, agents, or by Third Parties acting on their behalf, while performing
activities under this Agreement; provided, however, that Acceleron Improvements
shall not include any Improvement that is a Celgene Improvement or Joint
Improvement.
1.4    “Acceleron Know-How” means any Know-How (other than Acceleron
Improvements and Acceleron Collaboration IP) that is either Controlled by
Acceleron on the Effective Date or comes within Acceleron’s Control during the
Agreement Term and is necessary or useful to Develop, Manufacture or
Commercialize a Licensed Compound or a Licensed Product in the Field. For
avoidance of doubt, to the extent that antibodies that bind to [* * *] or
receptors to which [* * *] binds are necessary or useful to Develop, Manufacture
or Commercialize a Licensed Compound or a Licensed Product in the Field, then,
to the extent Controlled by Acceleron on the Effective Date

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or during the Agreement Term, the composition of such antibodies are included in
the Acceleron Know-How.
1.5    “Acceleron Patent Rights” means (a) the United States and foreign patents
and patent applications listed in Schedule 1.5 and, effective upon the dates and
pursuant to the terms set forth in Section 7.2, the [* * *] Antibody Patent
Rights, [* * *] Antibody Patent Rights and [* * *] Antibody Patent Rights, as
applicable, (b) any Patent Rights arising from those patents and patent
applications during the Agreement Term, (c) any Patent Rights resulting from
Acceleron Improvements or Acceleron Collaboration IP, and (d) any other Patent
Rights Controlled by Acceleron as of the Effective Date or during the Agreement
Term (but, in the case of Third Party Intellectual Property Controlled by
Acceleron during the Agreement Term, subject to Section 5.6.3(c)); all of the
above (a) through (d) solely to the extent that such Patent Rights claim the
manufacture or use of a Licensed Compound or a Licensed Product, claim a
composition of matter of or including a Licensed Compound or a Licensed Product,
or are necessary or useful to Develop, Manufacture or Commercialize a Licensed
Compound or a Licensed Product in the Field. For the avoidance of doubt, any
Patent Rights that claim the use of a Licensed Compound or Licensed Product in
combination with another product (including the use of a Licensed Compound or
Licensed Product as part of a Combination Product) shall be included within
“Acceleron Patent Rights” (if otherwise within this definition); provided that
such inclusion shall not cause “Acceleron Patent Rights” to include any other
Patent Rights that claim such other product or the use or manufacture of such
other product (or the other active component of a Combination Product) that is
not a Licensed Compound or Licensed Product.
1.6    “Acceleron Technology” means Acceleron Patent Rights, Acceleron Know-How,
Acceleron Improvements, and Acceleron Collaboration IP.
1.7    “ACE-536 Agreement” means the Collaboration, License and Option
Agreement, by and between Acceleron and Celgene, dated as of August 2, 2011, as
amended.
1.8    “ActRIIA” means (a) any fusion protein containing at least [* * *]
consecutive amino acids from the extracellular portion of human ActRIIA or a
mammalian ortholog thereof, linked to an Fc region of an immunoglobulin, (b) any
dimers or multimers of (a), and (c) any nucleic acid encoding a protein of (a)
or (b). For clarity, and without limiting the foregoing, the term “ActRIIA”
specifically includes the fusion protein identified as ACE-011 and the protein
having the sequence of [* * *].
1.9    “ActRIIB” means (a) any fusion protein containing at least [* * *]
consecutive amino acids from the extracellular portion of human ActRIIB or a
mammalian ortholog thereof, linked to an Fc region of an immunoglobulin, (b) any
dimers or multimers of (a), and (c) any nucleic acid encoding a protein of (a)
or (b).  For clarity, and without limiting the foregoing, the term “ActRIIB”
specifically includes the fusion protein identified as ACE-031 and the protein
having the sequence of [* * *].
1.10    [“* * *”] means (i) the protein having the sequence set forth in GenBank
Entry [* * *] and dimers, multimers and fragments thereof and (ii) mammalian
orthologs of (i), and dimers, multimers and fragments thereof.

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1.11    “[* * *] Antibody” means any antibody that binds to [* * *] with a
dissociation constant (KD) of 500 picomolar or less. The terms “[* * *]
Antibody” and “[* * *] Antibody” may each include antibodies that bind to both
[* * *] and [* * *].
1.12    “[* * *] Antibody Patent Rights” means the United States and foreign
patents and patent applications listed in Schedule 1.12.
1.13    “[* * *]” means (i) the protein having the sequence set forth in GenBank
Entry [* * *] and dimers, multimers and fragments thereof and (ii) mammalian
orthologs of (i), and dimers, multimers and fragments thereof.
1.14    “[* * *] Antibody” means any antibody that binds to [* * *] with a
dissociation constant (KD) of 500 picomolar or less. The terms “[* * *]
Antibody” and “[* * *] Antibody” may each include antibodies that bind to both
[* * *] and [* * *].
1.15    “[* * *] Antibody Patent Rights” means the United States and foreign
patents and patent applications listed in Schedule 1.15.
1.16    “Adverse Event” means any side effect, injury, toxicity or sensitivity
reaction, or any unexpected incident, whether or not determined to be
attributable to any Licensed Product.
1.17    “Affiliate” means, with respect to a subject entity, another entity
that, directly or indirectly, controls, is controlled by, or is under common
control with such subject entity, for so long as such control exists. For
purposes of this definition only, “control” means ownership, directly or
indirectly through one or more Affiliates, of at least fifty percent (50%) of
the equity securities of the entity entitled to vote in the election of
directors (or, in the case of an entity that is not a corporation, in the
election of the corresponding managing authority, or in the case of a
partnership, the status as a general partner) or any other arrangement whereby
an entity controls or has the right to control the board of directors or
equivalent governing body or management of a corporation or other entity.
1.18    “Agreement Term” means the period commencing on the Effective Date and
ending upon the termination of this Agreement with respect to both North America
and the Territory outside North America, in accordance with Section 10.1.
1.19    “Applicable Law” means the applicable laws, rules and regulations,
including any rules, regulations, guidelines or other requirements of the
Regulatory Authorities, that may be in effect from time to time in the
Territory.
1.20    “Bankruptcy Code” means Title 11, United States Code, as amended, or
analogous provisions of Applicable Law outside the United States.
1.21    “[* * *]” means (i) the protein having the sequence set forth in GenBank
Entry [* * *] and dimers, multimers and fragments thereof and (ii) mammalian
orthologs of (i), and dimers, multimers and fragments thereof.
1.22    “[* * *] Antibody” means any antibody that binds to [* * *] with a
dissociation constant (KD) of 500 picomolar or less.

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1.23    “[* * *] Antibody Patent Rights” means the United States and foreign
patents and patent applications listed in Schedule 1.23.
1.24    “Business Day” means a day on which banking institutions in Boston,
Massachusetts and Trenton, New Jersey are open for business.
1.25    “Celgene Collaboration IP” means any and all Collaboration IP created,
conceived or reduced to practice, and, in the case of patentable Collaboration
IP, Invented, solely by Celgene, its Affiliates, agents or by Third Parties
acting on their behalf, while performing activities under this Agreement;
provided, however, that Celgene Collaboration IP shall not include any
Collaboration IP that is Acceleron Collaboration IP or Joint Collaboration IP.
1.26    “Celgene Development Activities” means (i) all Development activities,
including Phase 2B Clinical Trials, Phase 3 Clinical Trials, any formulation
development for Licensed Compounds or Licensed Products taking place after the
end of Phase 2A Clinical Trials, and any other Development activities taking
place after the end of Phase 2A Clinical Trials, undertaken by Celgene pursuant
to this Agreement for the purpose of obtaining Regulatory Approval in North
America and Europe, (ii) all Development activities, including all Clinical
Trials and other Development activities undertaken by Celgene pursuant to this
Agreement for the purpose of obtaining Regulatory Approvals outside North
America and Europe and (iii) all Development activities to be conducted by or on
behalf of Celgene or its Affiliates in the PH Field in the Territory solely to
the extent expressly provided in this Agreement or otherwise agreed to in
writing by Celgene; provided that, for clarity, Celgene Development Activities
shall not include any PH Field Development Activities other than those set forth
in this clause (iii) of this Section 1.26.
1.27    “Celgene Development Plan/Budget” means (a) the comprehensive plan for
the Development of any Licensed Compound or Licensed Product for the purpose of
obtaining Regulatory Approval in the Celgene Field in the Territory, including
activities designed to generate the preclinical, process
development/manufacturing scale-up, clinical and regulatory information required
for filing NDAs for Licensed Products in the Celgene Field in the Territory, and
(b) a budget setting forth the internal and external resources and expenses for
such Development activities.
1.28    “Celgene Field” means (i) the treatment, prevention, modulation, or
diagnosis of any disease, disorder, or condition in humans outside the PH Field,
and (ii) any and all research uses and applications related to the Development,
Manufacture and Commercialization of Licensed Compounds or Licensed Products
outside the PH Field.
1.29    “Celgene Field Net Sales” means the aggregate gross invoice prices of
all Licensed Products in the Celgene Field sold by or on behalf of a Party or
its Affiliates and Sublicensees (including by the Distributing Party or its
designee for a Licensed Product in the Celgene Field pursuant to this
Agreement), to Third Parties anywhere within the Territory, including wholesale
distributors, less deductions from such amounts calculated in accordance with
U.S. GAAP so as to arrive at “net product sales” under U.S. GAAP, and further
reduced by write-offs of accounts receivables or increased for collection of
accounts that were previously written off.

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The transfer of Licensed Products between or among Celgene, Acceleron and their
Affiliates and Sublicensees shall be excluded from the computation of Celgene
Field Net Sales.
Notwithstanding the foregoing, in the event a Licensed Compound or Licensed
Product is sold as a Combination Product, Celgene Field Net Sales shall be
calculated by multiplying the Celgene Field Net Sales of the Combination Product
by the fraction A/(A+B), where A is the gross invoice price of the Licensed
Compound or Licensed Product if sold separately in a country and B is the gross
invoice price of the other product(s) included in the Combination Product if
sold separately in such country. In the event no such separate sales are made by
or on behalf of Celgene or its Affiliates or Sublicensees in a country, Celgene
Field Net Sales of the Combination Product shall be calculated in a manner to be
negotiated and agreed upon by the Parties, reasonably and in good faith, prior
to any sale of such Combination Product, which shall be based upon the
respective cost of goods sold of the active components of such Combination
Product.
1.30    “Celgene Field Royalty Rate” means, with respect to a Licensed Product
for which Celgene is the Distributing Party in the Celgene Field, the royalty
rate payable by Celgene to Acceleron on Celgene Field Net Sales of such Licensed
Product pursuant to Section 5.6.1(a), taking into account any adjustments of
such rate under this Agreement, including under Section 5.6.3.
1.31    “Celgene Improvements” means (a) any and all Improvements to the Joint
Technology created, conceived or reduced to practice, and, in the case of
patentable Improvements, Invented, solely by Celgene, its Affiliates, agents or
by Third Parties acting on their behalf, while performing activities under this
Agreement; and (b) any and all Improvements to the Celgene Technology created,
conceived or reduced to practice, and, in the case of patentable Improvements,
Invented, solely by either Party, its Affiliates, agents or by Third Parties
acting on their behalf or jointly by the Parties, their respective Affiliates,
agents or by Third Parties acting on their behalf, while performing activities
under this Agreement; provided, however, that Celgene Improvements shall not
include any Improvement that is an Acceleron Improvement or Joint Improvement.
1.32    “Celgene Know-How” means any Know-How (other than Celgene Improvements
and Celgene Collaboration IP) that is either Controlled by Celgene on the
Effective Date or comes within Celgene’s Control during the Agreement Term that
Celgene, in its sole discretion, actually uses and is necessary to Develop,
Manufacture or Commercialize a Licensed Compound or a Licensed Product in the
Field.
1.33    “Celgene Patent Rights” means (a) any Patent Rights resulting from
Celgene Improvements or Celgene Collaboration IP and (b) any other Patent Rights
Controlled by Celgene as of the Effective Date or during the Agreement Term,
other than the Acceleron Patent Rights, that Celgene, in its sole discretion,
actually uses and are necessary to Develop, Manufacture or Commercialize a
Licensed Compound or a Licensed Product in the Field; for each of (a) and (b)
above, solely to the extent that such Patent Rights claim the manufacture or use
of a Licensed Compound or a composition of matter of or including a Licensed
Compound. For the avoidance of doubt, any Patent Rights that claim the use of a
Licensed Compound or Licensed Product in combination with another product
(including the use of a Licensed Compound or Licensed Product as part of a
Combination Product) shall be included within “Celgene Patent Rights” (if
otherwise within this definition); provided that such inclusion shall not cause
“Celgene Patent Rights” to include any

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other Patent Rights that claim such other product or the use or manufacture of
such other product (or the other active component of a Combination Product) that
is not a Licensed Compound or Licensed Product.
1.34    “Celgene Technology” means Celgene Know-How, Celgene Patent Rights,
Celgene Improvements, and Celgene Collaboration IP.
1.35    “Change of Control” means, with respect to a Party, (i) a merger or
consolidation of such Party with a Third Party which results in the voting
securities of such Party outstanding immediately prior thereto ceasing to
represent at least fifty percent (50%) of the combined voting power of the
surviving entity immediately after such merger or consolidation, or (ii) a
transaction or series of related transactions in which a Third Party, together
with its Affiliates, becomes the beneficial owner of fifty percent (50%) or more
of the combined voting power of the outstanding securities of such Party, or
(iii) the sale or other transfer to a Third Party of all or substantially all of
such Party’s business to which the subject matter of this Agreement relates.
1.36    “Clinical Supplies” means supplies of Licensed Compound and Licensed
Product Manufactured by or on behalf of Celgene or Acceleron in compliance with
GLP and GMP and meeting the FDA Guidance for Biologics License Applications,
Product License Applications/Establishment License Applications, New Drug
Applications, and supplements and amendments to those applications to Center for
Biologics Evaluation and Research (CBER) and EMA guidances, in each case, if
required given the intended use, and ready to be used for the conduct of
pre-clinical or human clinical trials of such Licensed Product in the Field.
1.37    “Clinical Trial” means a study in humans that is conducted in accordance
with GCP and is designed to generate data in support of an NDA.
1.38    “Collaboration IP” means (a) any and all ideas, information, Know-How,
data research results, writings, inventions, discoveries, modifications,
enhancements, derivatives, new uses, developments, techniques, materials,
compounds, products, designs, processes or other technology or intellectual
property, whether or not patentable or copyrightable, in each case, that is not
an improvement to then-existing Acceleron Technology, Celgene Technology, or
Joint Technology and is developed by either Party, its Affiliates or Third
Parties acting on their behalf while performing activities under this Agreement,
and (b) all Patent Rights and other intellectual property rights in any of the
foregoing.
1.39    “Combination Product” means any product that comprises a Licensed
Compound or Licensed Product sold in conjunction with another active component
so as to be a combination product (whether packaged together or in the same
therapeutic formulation).
1.40    “Commercial Supplies” means supplies of Licensed Product in final
packaged form Manufactured by or on behalf of Celgene or Acceleron in compliance
with GMP and meeting FDA Guidance for Biologics License Applications, Product
License Applications/Establishment License Applications, New Drug Applications,
and supplements and amendments to those applications to Center for Biologics
Evaluation and Research (CBER) and EMA guidances, in each case, if required

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given the intended use, and ready to be Commercialized by Acceleron or by
Celgene, or their respective Affiliates or Sublicensees, as applicable, for use
in the Field, in the Territory.
1.41    “Commercialization” means any and all activities using, constituting,
importing, marketing, distributing, offering for sale and selling Licensed
Products in the Field in the Territory following or in expectation of receipt of
Regulatory Approval (but excluding Development) and shall include Promotion as
well as activities required to fulfill ongoing regulatory obligations, including
adverse event reporting but excluding any Post-Approval Clinical Trials. When
used as a verb, “Commercialize” means to engage in Commercialization.
1.42    “Commercially Reasonable Efforts” means, for each Party, the carrying
out of obligations in a diligent and sustained manner using such effort and
employing such resources as would normally be exerted or employed by a
similarly-situated biopharmaceutical company for a product of similar market
potential, and at a similar stage of its Development or product life, taking
into consideration safety and efficacy, Development Costs, Operating Costs, the
anticipated prescription label, the nature of the Licensed Product, the clinical
setting in which it is expected to be used, competitiveness of the marketplace,
regulatory environment, the patent or other proprietary position of the Licensed
Product, and other conditions then prevailing. Commercially Reasonable Efforts
shall be determined on a country-by-country basis; provided that, with respect
to the co-Promotion obligations hereunder, such standard shall be based on an
established biopharmaceutical company rather than a similarly-situated
biopharmaceutical company.
1.43    “Confidential Information” means, with respect to each Party,
proprietary data or information that belongs in whole or in part to such Party,
its Affiliates or Sublicensees, and is disclosed to the other Party.
Confidential Information of Celgene includes all Celgene Technology, the reports
delivered by Celgene to Acceleron hereunder, all proprietary data and
information of Celgene disclosed by Celgene at the Joint Development Committee
or Joint Commercialization Committee meetings, and any information designated as
Confidential Information of Celgene hereunder. Confidential Information of
Acceleron includes Acceleron Technology, the reports delivered by Acceleron to
Celgene hereunder, all proprietary data and information of Acceleron disclosed
by Acceleron at the Joint Development Committee or Joint Commercialization
Committee meetings, and any information designated as Confidential Information
of Acceleron hereunder. For clarity, information that is not otherwise
Confidential Information of a Party hereunder shall not become Confidential
Information by inclusion in a report delivered by such Party to the other Party.
Confidential Information of both Parties includes Joint Technology and the terms
and conditions of this Agreement. Confidential Information shall not include (as
determined by competent documentation) information that:
(a)    was known by the receiving Party or its Affiliates prior to its date of
disclosure to the receiving Party; or
(b)    either before or after the date of the disclosure to the receiving Party
is lawfully disclosed to the receiving Party or its Affiliates by sources (other
than the disclosing Party) rightfully in possession of the Confidential
Information; or

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(c)    either before or after the date of the disclosure to the receiving Party
or its Affiliates becomes published or generally known to the public (including
information known to the public through the sale of products in the ordinary
course of business) through no fault or omission on the part of the receiving
Party, its Affiliates or its Sublicensees; or
(d)    is independently developed by or for the receiving Party or its
Affiliates without reference to or reliance upon the Confidential Information.
1.44    “Contract Year” means each calendar year during the Agreement Term;
provided, however, that the first Contract Year began on the Effective Date and
ended on December 31, 2008. Each Contract Year shall be divided into four (4)
“Contract Quarters” ending respectively on March 31, June 30, September 30 and
December 31.
1.45    “Control” or “Controlled” means with respect to any (a) material, item
of information, method, data or other Know-How or (b) Patent Rights or other
intellectual property right, the possession (whether by ownership or license,
other than pursuant to this Agreement) by a Party or its Affiliates of the
ability to grant to the other Party access or a license as provided herein under
such item or right without, in the case of such rights that are licensed from a
Third Party, violating the terms of any agreement or other arrangement with any
Third Party existing before or after the Effective Date.
1.46    "Designated Countries" means the United States, member countries of the
European Patent Convention, member countries of the Eurasian Patent Convention,
Canada, Australia, Japan, South Korea, China, India and Brazil.
1.47    “Development” means all pre-clinical and clinical activities performed
by or on behalf of either Party with respect to Licensed Compounds or Licensed
Products in the Field in the Territory in an indication, or for the purpose of
obtaining Regulatory Approval with respect to such indication, from the
Effective Date until Regulatory Approval of such Licensed Compounds or Licensed
Products is obtained for the indication being studied, including: (a)
identification and early pre-clinical testing of Licensed Compounds; (b)
toxicology, regulatory affairs, pre-clinical studies and clinical trials in
accordance with the GLPs, GCPs and GMPs or other designated quality standards
and Applicable Laws; and (c) all Manufacturing activities (until such time as
Manufacturing of Commercial Supplies commences) relating to developing the
ability to Manufacture Licensed Product, including process and formulation
development, process validation, manufacturing scale-up, manufacturing and
analytical development, and quality assurance and quality control. When used as
a verb, “Develop” means to engage in Development.
1.48    “Development Costs” means FTE Costs and other costs specifically
identifiable or allocable to Development or regulatory activities for each
Licensed Compound and Licensed Product and development of the Manufacturing
process, as well as Manufacturing of Clinical Supplies, in each case, actually
incurred by Celgene or Acceleron, or their respective Affiliates. Development
Costs shall include:

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(a)    the costs associated with the production of Clinical Supplies (including
$[* * *] of Acceleron costs for the 960 vials of Clinical Supplies produced by
Acceleron prior to the Effective Date, which vials will be used in connection
with Development pursuant hereto) for all Clinical Trials (including the costs
associated with the transfer of Clinical Supplies to the site of use and
including pre-Commercialization and post-Commercialization Clinical Trials),
which costs of Clinical Supplies shall include such costs that would ordinarily
be included as a “Cost of Goods Sold” under U.S. GAAP for a similar product,
made on the basis of theoretical full capacity operation of the relevant
facility, and is set forth in the Development Plan/Budget under the Amended
Agreement;
(b)    the costs of studies on the toxicological, pharmacological, metabolic or
clinical aspects of a Licensed Compound or Licensed Product necessary for the
purpose of obtaining Regulatory Approval of a Licensed Compound or a Licensed
Product;
(c)    the costs of process and formulation development, process improvement and
scale-up costs, validation costs, including qualification lots and costs for
preparing, submitting, and reviewing or developing data or information for the
purpose of submission to a governmental authority to obtain manufacturing or
marketing approval of a Licensed Compound or a Licensed Product, in each case,
to the extent that such costs and expenses are associated with Development
activities;
(d)    the costs associated with the transfer to a Third Party of, and
implementation by a Third Party of, manufacturing technology necessary for the
Development of a Licensed Product or Licensed Compound;
(e)    costs of data management, statistical designs and studies, document
preparation and other administration expenses associated with all Clinical
Trials;
(f)    Third Party Intellectual Property Costs associated with Development
activities and the Manufacture of Clinical Supplies that are deemed Development
Costs pursuant to Section 5.6.3(c);
(g)    Patent Procurement Costs to the extent provided in Section 8.2.4(b); and
(h)    capital expenditures incurred by Acceleron and approved pursuant to
Section 2.4.1.
In determining Development Costs chargeable under this Agreement, the Parties
shall use their respective project accounting systems (which must be consistent
with the terms of this Agreement). The Parties shall consistently apply
methodologies for calculating and allocating Development Costs based on their
internal accounting systems (which must be consistent with the terms of this
Agreement). Notwithstanding anything in this definition to the contrary, only
those Development Costs that are contemplated by the Development Plan/Budget
shall be chargeable by either Party as Development Costs with any cost overruns
treated in the manner set forth in Section 5.5.4. Except

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to the extent included in cost of Clinical Supplies described in clause (a)
above, expenses incurred by either Party for equipment, materials and supplies
utilized in performing its activities under the Development Plan/Budget shall
not be separately charged as Development Costs, except for those expenses
incurred by either Party, as set forth in the Development Plan/Budget, in the
purchase or making of equipment, materials or supplies (other than common
laboratory supplies, e.g., pipettes, test tubes, petri dishes, reagents, and the
like) that are to be used exclusively in connection with the performance of
either Party’s activities under the Development Plan/Budget (e.g., laboratory
animals, placebo supplies, etc.), which expenses shall be charged as Development
Costs at either Party’s actual out-of-pocket expense incurred in purchasing or
making such equipment, materials or supplies.
1.49    “Development Plan/Budget” means either or both of the Celgene
Development Plan/Budget or the PH Field Development Plan/Budget.
1.50    “Effective Date” means the date defined as the “Effective Date” in the
Original Agreement.
1.51    “EMA” means the Regulatory Agency known as either the European Medicines
Agency or the European Agency for the Evaluation of Medicinal Products, or a
successor agency with responsibilities comparable to those of the European
Medicines Agency or the European Agency for the Evaluation of Medicinal
Products.
1.52    “Europe” means Switzerland and all countries in which the Development or
Commercialization of a Licensed Compound or Licensed Product is regulated by the
EMA.
1.53    “Executive Officers” means the Chief Executive Officer of Celgene (or a
designee of such Chief Executive Officer) and the Chief Executive Officer of
Acceleron (or a designee of such Chief Executive Officer).
1.54    “FDA” means the United States Food and Drug Administration, or a
successor agency in the United States with responsibilities comparable to those
of the United States Food and Drug Administration.
1.55    “Field” means (i) the treatment, prevention, modulation, or diagnosis of
any disease, disorder, or condition in humans, and (ii) any and all research
uses and applications related to the Development, Manufacture and
Commercialization of Licensed Compounds or Licensed Products.
1.56    “First Amendment Effective Date” means August 2, 2011.
1.57    “First Commercial Sale” means, with respect to a given Licensed Product
in a country in the Territory, the first commercial sale in an arms’ length
transaction of such Licensed Product to a Third Party by or on behalf of a
Party, its Affiliate or its Sublicensee in such country following receipt of
applicable Regulatory Approval of such Licensed Product in such country.
1.58    “FTE Costs” means, for any Contract Quarter, the FTE Rate multiplied by
the number of hours of service spent in that quarter by employees of Celgene or
Acceleron, or their respective Affiliates, working directly on the Development
or Commercialization of a Licensed Product.

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1.59    “FTE Rate” means [$* * *] (as of Contract Year 2017) for employees of
each of Acceleron and its Affiliates and Celgene and its Affiliates, which rate
may be adjusted annually by each Party based on changes in the Consumer Price
Index (as quoted by the U.S. Department of Labor, Bureau of Labor Statistics).
1.60    “Fully Loaded Cost” means all costs actually incurred by Celgene or its
Affiliates in the Manufacture of applicable therapeutic ingredients, finished
products, related inputs, and services (a) supplied by a Third Party or (b)
Manufactured directly by Celgene or its Affiliates; it being understood and
agreed that (i) in the case of costs referred to in clause (a) of this sentence
where a Third Party is the Manufacturer, Fully Loaded Cost will equal [* * *] of
the amounts invoiced by (1) such Third Party or (2) any other Third Party
engaged by Celgene to provide product quality assurance/control services (e.g.,
release testing, stability testing) with respect to the applicable product, and
(ii) in the case of costs referred to in clause (b) of this sentence where
Celgene or its Affiliate is the Manufacturer, Fully Loaded Cost will equal [* *
*], which Manufacturing costs: (x) will include the cost of [* * *], and other
direct and identifiable variable costs and appropriate direct and identifiable
costs (or appropriate allocation thereof) for [* * *] (to the extent consistent
with industry practice), and [* * *], including any reasonable overhead
allocated thereto, and will include costs associated with the filing and
maintaining of regulatory submissions for the Licensed Product [* * *] and (y)
will be calculated in accordance with the accounting standards and Celgene’s
policies and procedures for its other products, in each case, consistently
applied (and such [* * *] costs will be allocated consistent with the accounting
standards and the other Celgene products in that facility).
1.61    “GCP” means the international ethical and scientific quality standards
for designing, conducting, recording, and reporting trials that involve the
participation of human subjects. In the United States, GCP shall be based on
Good Clinical Practices established through FDA guidances (including ICH E6).
1.62    “Generic Product” means a product on the market commercialized by a
Third Party (excluding Sublicensees) that (a) is approved, under any then
existing laws and regulations in the applicable country pertaining to approval
of “generic” biologic products, as a “generic” version of a Licensed Product
labeled for substantially similar indications as such Licensed Product; or (b)
otherwise is recognized as a biosimilar or interchangeable biological product to
the Licensed Product by the applicable Regulatory Authority.
1.63    “GLP” means the current Good Laboratory Practice (or similar standards)
for the performance of laboratory activities for pharmaceutical products as are
required by applicable Regulatory Authorities. In the United States, Good
Laboratory Practices are established through FDA regulations (including 21 CFR
Part 58), FDA guidances, FDA current review and inspection standards and current
industry standards.
1.64    “GMP” means current Good Manufacturing Practices. In the United States,
GMP shall be as defined under the rules and regulations of the FDA, as the same
may be amended from time to time.
1.65    “HSR Act” means the Hart-Scott-Rodino Act of 1976, as amended.

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1.66    “Improvements” means (a) any and all ideas, information, Know-How, data
research results, writings, inventions, discoveries, modifications,
enhancements, derivatives, new uses, developments, techniques, materials,
compounds, products, designs, processes or other technology or intellectual
property, whether or not patentable or copyrightable, in each case, that is an
improvement to then-existing Acceleron Technology, Celgene Technology, or Joint
Technology and is developed by either Party, its Affiliates or Third Parties
acting on their behalf while performing activities under this Agreement, and (b)
all Patent Rights and other intellectual property rights in any of the
foregoing.
1.67    “IND” means an Investigational New Drug Application, as defined in the
Food Drug & Cosmetics Act, or similar application or submission that is required
to be filed with any Regulatory Authority before beginning clinical testing of a
Licensed Product in human subjects.
1.68    “Invented” means the act of invention by inventors, as determined in
accordance with U.S. patent laws.
1.69    “Joint Collaboration IP” means any and all Collaboration IP created,
conceived or reduced to practice, and, in the case of patentable Collaboration
IP, Invented, jointly by Acceleron and Celgene, their respective Affiliates,
agents or by Third Parties acting on their behalf, while performing activities
under this Agreement; provided, however, that Joint Collaboration IP shall not
include any Collaboration IP that is Acceleron Collaboration IP or Celgene
Collaboration IP.
1.70    “Joint Improvements” means (a) any and all Improvements to the Acceleron
Technology created, conceived or reduced to practice, and, in the case of
patentable Improvements, Invented, solely by Celgene, its Affiliates, agents or
by Third Parties acting on their behalf, while performing activities under this
Agreement; and (b) any and all Improvements to the Acceleron Technology or Joint
Technology created, conceived or reduced to practice, and, in the case of
patentable Improvements, Invented, jointly by Acceleron and Celgene, their
respective Affiliates, agents or Sublicensees or by Third Parties acting on
their behalf, while performing activities under this Agreement; provided,
however, that Joint Improvements shall not include any Improvement that is a
Celgene Improvement or Acceleron Improvement.
1.71    “Joint Patent Rights” means any Patent Rights resulting from any Joint
Improvements or Joint Collaboration IP.
1.72    “Joint Technology” means Joint Improvements, Joint Patent Rights, and
Joint Collaboration IP.
1.73    “Know-How” means any non-public, proprietary invention, discovery,
process, method, composition, formula, procedure, protocol, technique, result of
experimentation or testing, information, data, material, technology or other
know-how, whether or not patentable or copyrightable. Know-How shall not include
any Patent Rights with respect thereto.
1.74    “Licensed Compound” means ActRIIA, and, effective upon the dates and
pursuant to the terms set forth in Section 7.2, any applicable Option Compound.

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1.75    “Licensed Product” means any preparation in final form that contains a
Licensed Compound.
1.76    “Major Market Countries” means the United States, the European Union,
and Japan.
1.77    “Manufacturing” means, as applicable, all activities associated with the
production, manufacture, processing, filling, finishing, packaging, labeling,
shipping, and storage of Licensed Compounds or Licensed Products, including
process and formulation development, process validation, stability testing,
manufacturing scale-up, pre-clinical, clinical and commercial manufacture and
analytical development, product characterization, quality assurance and quality
control, whether such activities are conducted by a Party, its Affiliates or a
Third Party contractor of such Party. When used as a verb, “Manufacture” means
to engage in Manufacturing.
1.78    “Net Sales” means the aggregate gross invoice prices of all Licensed
Products in the Field sold by or on behalf of a Party, or their respective
Affiliates and Sublicensees (including by the Distributing Party or its designee
for a Licensed Product in the PH Field or Celgene Field, as applicable, pursuant
to this Agreement), to Third Parties anywhere within the Territory, including
wholesale distributors, less deductions from such amounts calculated in
accordance with U.S. GAAP so as to arrive at “net product sales” under U.S.
GAAP, and further reduced by write-offs of accounts receivables or increased for
collection of accounts that were previously written off.
The transfer of Licensed Products between or among Celgene, Acceleron and their
Affiliates and Sublicensees shall be excluded from the computation of Net Sales.
Notwithstanding the foregoing, in the event a Licensed Compound or Licensed
Product is sold as a Combination Product, Net Sales shall be calculated by
multiplying the Net Sales of the Combination Product by the fraction A/(A+B),
where A is the gross invoice price of the Licensed Compound or Licensed Product
if sold separately in a country and B is the gross invoice price of the other
product(s) included in the Combination Product if sold separately in such
country. In the event no such separate sales are made by or on behalf of
Celgene, Acceleron or their respective Affiliates or Sublicensees in a country,
Net Sales of the Combination Product shall be calculated in a manner to be
negotiated and agreed upon by the Parties, reasonably and in good faith, prior
to any sale of such Combination Product, which shall be based upon the
respective cost of goods sold of the active components of such Combination
Product.
1.79    “New Drug Application” or “NDA” means a New Drug Application filed with
the FDA as described in 21 C.F.R. § 314, a Biological License Application (BLA)
pursuant to 21 C.F.R. § 601.2, or any equivalent or any corresponding
application for Regulatory Approval (not including pricing and reimbursement
approval) in any country or regulatory jurisdiction other than the United
States.
1.80    “Non-Prosecuting Party” means, with respect to a particular Patent
Right, the Party which is not the Prosecuting Party.
1.81    “North America” means the United States, including its territories and
possessions, Canada and Mexico.

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1.82    “Operating Costs” means, costs of goods sold, all Sales Force Costs, all
Third Party Intellectual Property Costs associated with the sale of Licensed
Product that are deemed Operating Costs pursuant to Section 5.6.3(c), all costs
associated with the distribution, marketing and sale of Licensed Product
(including costs for preparing and reproducing detailing aids, promotional
materials, professional education, and product related public relations).
Notwithstanding anything in this definition to the contrary, only those
Operating Costs that are contemplated by the Commercialization Plan/Budget shall
be chargeable by either Party as Operating Costs, with any cost overruns treated
in the manner set forth in Section 5.5.4.
1.83    “Option Compounds” means [* * *] Antibodies, [* * *] Antibodies, and [*
* *] Antibodies.
1.84    “Option Patent Rights” means the [* * *] Antibody Patent Rights, [* * *]
Antibody Patent Rights, and [* * *] Antibody Patent Rights.
1.85    “Patent Procurement Costs” means the fees and expenses paid by the
Parties or their Affiliates to outside legal counsel and experts, and
Prosecuting expenses, incurred after the Effective Date, in connection with the
Prosecution of Acceleron Patent Rights, Joint Patent Rights and Celgene Patent
Rights, including the costs of patent interference, reexamination, reissue,
opposition and revocation proceedings.
1.86    “Patent Rights” means all patents (including all reissues, extensions,
substitutions, confirmations, re-registrations, re-examinations, invalidations,
supplementary protection certificates, and patents of addition) and patent
applications (including all provisional applications, continuations,
continuations-in-part, and divisions), in each case, anywhere in the world.
1.87    “PH Field” means (i) the treatment, prevention, modulation, or diagnosis
of pulmonary hypertension in humans, and (ii) any and all research uses and
applications related to the Development, Manufacture and Commercialization of
Sotatercept Licensed Compounds or Sotatercept Licensed Products for the
treatment, prevention, modulation, or diagnosis of pulmonary hypertension in
humans.
1.88    “PH Field Celgene Patent Right” means any Celgene Patent Right that
contains a claim specifically directed at the Development, Manufacture or
Commercialization of a Sotatercept Licensed Compound or Sotatercept Licensed
Product in the PH Field in the Territory.
1.89    “PH Field Development Activities” means Development activities performed
with respect to a Sotatercept Licensed Compound or Sotatercept Licensed Product
in the PH Field in the Territory.
1.90    “PH Field Development Plan/Budget” means (a) the comprehensive plan for
the Development of any Sotatercept Licensed Compound or Sotatercept Licensed
Product for the purpose of obtaining Regulatory Approval in the PH Field in the
Territory, including activities designed to generate the preclinical, process
development/manufacturing scale-up, clinical and regulatory information required
for filing NDAs in the Territory, and (b) a budget setting forth the internal
and external resources and expenses for such Development activities. Solely if
and to the extent that Celgene agrees in writing to perform any Development
activities in the PH Field which constitute Celgene Development Activities, the
PH Field Development Plan/Budget shall be

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amended by the Parties to provide for such Development activities and a budget
setting forth the internal and external resources and expenses therefor.
1.91    “PH Field Net Sales” means the aggregate gross invoice prices of all
Sotatercept Licensed Products in the PH Field sold by or on behalf of a Party or
its Affiliates and Sublicensees (including by the Distributing Party or its
designee for a Licensed Product in the PH Field pursuant to this Agreement) to
Third Parties anywhere within the Territory, including wholesale distributors,
less deductions from such amounts calculated in accordance with U.S. GAAP so as
to arrive at “net product sales” under U.S. GAAP, and further reduced by
write-offs of accounts receivables or increased for collection of accounts that
were previously written off.
The transfer of Sotatercept Licensed Products between or among Acceleron,
Celgene and their respective Affiliates and Sublicensees shall be excluded from
the computation of PH Field Net Sales.
Notwithstanding the foregoing, in the event a Sotatercept Licensed Compound or
Sotatercept Licensed Product is sold as a Combination Product, PH Field Net
Sales shall be calculated by multiplying the PH Field Net Sales of the
Combination Product by the fraction A/(A+B), where A is the gross invoice price
of the Sotatercept Licensed Compound or Sotatercept Licensed Product if sold
separately in a country and B is the gross invoice price of the other product(s)
included in the Combination Product if sold separately in such country. In the
event no such separate sales are made by or on behalf of Acceleron or its
Affiliates or Sublicensees in a country, PH Field Net Sales of the Combination
Product shall be calculated in a manner to be negotiated and agreed upon by the
Parties, reasonably and in good faith, prior to any sale of such Combination
Product, which shall be based upon the respective cost of goods sold of the
active components of such Combination Product.
1.92    “PH Field Royalty Rate” means, with respect to a Sotatercept Licensed
Product for which Acceleron is the Distributing Party in the PH Field, the
royalty rate payable by Acceleron to Celgene on PH Field Net Sales of such
Licensed Product pursuant to Section 5.7.1(a), taking into account any
adjustments of such rate under this Agreement, including under Section 5.7.3.
1.93    “PH Field Royalty Term” means the period of time beginning on the date
of First Commercial Sale of a Sotatercept Licensed Product in the PH Field in a
particular country and ending, on a Sotatercept Licensed Product-by-Sotatercept
Licensed Product and country-by-country basis, on the later of (i) the date on
which the offering for sale, selling, making, having made, using or importing
such Sotatercept Licensed Product in the PH Field is no longer covered by a
Valid Claim of an Celgene Patent Right in such country and (ii) the eleventh
(11th) anniversary of the First Commercial Sale of such Sotatercept Licensed
Product in the PH Field in such country.
1.94    “Phase 1 Clinical Trial” means, as to a specific pharmaceutical product,
a Clinical Trial in humans of the safety of such product in healthy volunteers
or a limited patient population, or human clinical studies directed toward
understanding the mechanisms or metabolism of the product. A Phase 1 Clinical
Trial shall be deemed initiated upon the dosing of the first subject or patient.

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1.95    “Phase 2A Clinical Trial” means, as to a specific pharmaceutical
product, the first Clinical Trial in humans that is intended to study the
safety, dosage and initial efficacy in a limited patient population and is
prospectively designed to support the continued testing of the product in one or
more further Phase 2A Clinical Trials or Phase 2B Clinical Trials. A Phase 2A
Clinical Trial shall be deemed initiated upon the dosing of the first patient.
1.96    “Phase 2B Clinical Trial” means, as to a specific pharmaceutical
product, a Clinical Trial of the feasibility, safety, dose ranging and efficacy
of such product, that is prospectively designed to generate sufficient data (if
successful) to commence a Phase 3 Clinical Trial (or foreign equivalent) of such
product, as further defined in 21 C.F.R. 312.21(b) or the corresponding
regulation in jurisdictions other than the United States. A Phase 2B Clinical
Trial shall be deemed initiated upon the dosing of the first patient.
1.97    “Phase 3 Clinical Trial” means, as to a specific pharmaceutical product,
a pivotal Clinical Trial in humans performed to gain evidence with statistical
significance of the efficacy of such product in a target population, and to
obtain expanded evidence of safety for such product that is needed to evaluate
the overall benefit-risk relationship of such product, to form the basis for
approval of an NDA by a Regulatory Authority and to provide an adequate basis
for physician labeling, as described in 21 C.F.R. 312.21 (c), as amended from
time to time, or the corresponding regulation in jurisdictions other than the
United States. A Phase 3 Clinical Trial shall be deemed initiated upon the
dosing of the first patient.
1.98    “Post-Approval Clinical Trial” means (i) any Clinical Trial conducted to
satisfy a requirement of a Regulatory Authority in order to maintain a
Regulatory Approval and (ii) any Clinical Trial conducted after the first
Regulatory Approval in the same disease state for which the Licensed Compound or
Licensed Product received Regulatory Approval in the Territory.
1.99    “Product Trademarks” means the trademarks, service marks, accompanying
logos, trade dress and indicia of origin used in connection with the
distribution, marketing, Promotion and sale of each Licensed Product in the
Territory. For purposes of clarity, the term Product Trademarks shall not
include the corporate names and logos of either Party and shall include any
internet domain names incorporating such Product Trademarks.
1.100    “Promotion” means those activities, including detailing normally
undertaken by a Party’s sales force to implement marketing plans and strategies,
aimed at encouraging the appropriate use of a particular Licensed Product in a
specific indication. When used as a verb, “Promote” means to engage in
Promotion.
1.101    “Prosecuting Party” means, with respect to a particular Patent Right,
the Party having primary responsibility for and control over Prosecuting such
Patent Right, pursuant to Section 8.2.1(a)(i) or Section 8.2.2(b)(i).
1.102    “Regulatory Approval” means the approval necessary for the commercial
manufacture, distribution, marketing, Promotion, offer for sale, use, import,
export, and sale of a Licensed Product in a regulatory jurisdiction, excluding,
where required, separate pricing and reimbursement approvals.

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1.103    “Regulatory Authority” means any applicable supranational, national,
regional, state or local regulatory agency, department, bureau, commission,
counsel, or other government entity involved in granting of Regulatory Approval
for a Licensed Product in a regulatory jurisdiction within the Territory,
including the FDA and the EMA.
1.104    “Royalty Term” means (a) for all countries in the Territory outside
North America, the period of time beginning on the date of First Commercial Sale
of a Licensed Product in the Celgene Field in a particular country and ending,
on a Licensed Product-by-Licensed Product and country-by-country basis, on the
later of (i) the date on which the offering for sale, selling, making, having
made, using or importing such Licensed Product in the Celgene Field is no longer
covered by a Valid Claim of an Acceleron Patent Right in such country and (ii)
the eleventh (11th) anniversary of the First Commercial Sale of such Licensed
Product in the Celgene Field in such country; and (b) for all countries in North
America, to reflect Acceleron’s contribution in connection with the Development
Costs and co-Promotion of the Licensed Product, the period of time beginning on
the date of First Commercial Sale of a Licensed Product in the Celgene Field in
North America and ending, on a Licensed Product-by-Licensed Product and
country-by-country basis, on the date on which the Commercialization of such
Licensed Product in the Celgene Field in North America has ceased.
1.105    “Sales Force Costs” means all costs associated with sales
representatives and training of the sales representatives, sales meetings,
details, sales call reporting, work on managed care accounts, costs related to
customer service and other sales and customer service related expenses. If
either Party’s sales force sells products other than Licensed Products, only
that portion of sales force efforts that are related to the sale of Licensed
Products shall be included as Sales Force Costs hereunder.
1.106    “Salk” means the Salk Institute for Biological Studies.
1.107    “Salk License” means the Exclusive License Agreement dated May 10, 2004
between Acceleron and Salk, as amended by that certain letter agreement dated
February 12, 2008, a true and correct copy of which is attached hereto as
Exhibit A.
1.108    “Sotatercept Drug Product” means unlabeled, unpackaged vials of
Sotatercept Licensed Product.
1.109    “Sotatercept Licensed Compound” means the compound defined in Schedule
1.109.
1.110    “Sotatercept Licensed Product” means any preparation in final form that
contains a Sotatercept Licensed Compound.
1.111    “Subfield” means either of the PH Field and the Celgene Field. Without
limiting the foregoing, the Celgene Field shall be referred to as Celgene’s
“Subfield” herein and the PH Field shall be referred to as Acceleron’s
“Subfield” herein.

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1.112    “Sublicensee” means a sublicensee or licensee of all or part of the
rights licensed to or expressly retained by, as applicable, a Party under this
Agreement, in compliance with the terms of Section 4.4.
1.113    “Territory” means all the countries of the world.
1.114    “Third Party” means any person or entity other than a Party or any of
its Affiliates.
1.115    “Third Party Intellectual Property” means Patent Rights, trademarks and
trademark applications and registrations, copyrights and trade secrets owned by
a Third Party that would be necessary or useful to Develop, Manufacture or
Commercialize a Licensed Compound or a Licensed Product in the Field, the rights
to which are obtained by a Party through a license or other means after the
Effective Date.
1.116    “Third Party Intellectual Property Costs” means direct costs associated
with the licensing or other acquisition of Third Party Intellectual Property,
including upfront payments, development milestone payments, sales milestone
payments, royalties, and intellectual property acquisition fees. For the
avoidance of doubt, “Third Party Intellectual Property Costs” shall not include
any payments owed by Acceleron to Salk or any other third party licensor
pursuant to an agreement executed by Acceleron prior to the Effective Date (or,
with respect to any Option Compound, prior to the date that such Option Compound
is deemed a Licensed Compound in accordance with Article 7).
1.117    “U.S. GAAP” means generally accepted accounting principles in the
United States.
1.118    “Valid Claim” means a claim or pending claim of a Patent Right, which
claim or pending claim has not been revoked or held unenforceable, unpatentable
or invalid by a decision of a court or other governmental agency of competent
jurisdiction, which is not appealable or has not been appealed within the time
allowed for appeal, and which has not been abandoned, disclaimed, denied or
admitted to be invalid or unenforceable through reissue, re-examination or
disclaimer or other final, irrevocable action; provided, however, that if the
holding of such court or agency is later reversed by a court or agency with
overriding authority, the claim shall be reinstated as a Valid Claim with
respect to Net Sales made after the date of such reversal; provided further, on
a country-by-country basis, a patent application pending for more than five (5)
years shall not be considered to have any Valid Claim for purposes of this
Agreement unless and until a patent with respect to such application issues with
such claim.
1.119    Additional Definitions. The following terms have the meanings set forth
in the corresponding Sections of this Agreement:
Term
Section
“Acceleron Indemnitees”
11.7.1
“Acceleron NA Operating Costs”
5.5.3(b)
“Acquired Party Activity”
6.3
“Amended and Restated Effective Date”
Introduction
“Audited Party”
5.8.4(b)

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“Auditing Party”
5.8.4(b)
“Breaching Party”
10.2.1(a)
“Celgene Indemnitees”
11.7.2
“Clinical Supply Agreement”
2.4.2
“Commercial Supply Agreement”
2.4.3
“Commercialization Plan/Budget”
2.5
“Defending Party”
8.4.3
“Delivery Location”
2.4.1
“Distributing Party”
2.6.2
“Existing Drug Product”
2.4.1
“Forfeited Option Compound”
6.1.1
“Indemnitee”
11.7.3
“Infringement Claim”
8.4.1
“IP”
10.8
“JCC Chairperson”
3.2.3
“JDC Chairperson”
3.1.3
“Joint Development Committee”
3.1.1
“Joint Commercialization Committee”
3.2.1
“Losses”
11.7.1
“Option Program Payment”
7.2
“Paying Party”
5.8.1
“PH Field Royalty Report”
5.7.4
“PH Field Third Party Intellectual Property Notice”
5.7.3(c)
“Prosecuting” or “Prosecution”
8.2.1(a)(i)
“Publishing Party”
9.2
“Receiving Party”
5.8.1
“Reconciliation Statement”
5.5.5
“Restricted Activities”
4.8.2
“Restricted Product”
6.1.7(d)
“Royalty Report”
5.6.4
“Safety Concern”
2.3.5(a)
“Salk Patent Rights”
8.1.1
“SPC”
8.8
“Third Party Activity”
6.2.1
“Third Party Intellectual Property Notice”
5.6.3(c)

Article 2
COLLABORATION

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2.1    Development.
2.1.1.    Acceleron Responsibilities. Subject to the oversight of the Joint
Development Committee, Acceleron shall be solely responsible for managing all
Acceleron Development Activities relating to Licensed Compounds or Licensed
Products. Acceleron shall use Commercially Reasonable Efforts to carry out the
Acceleron Development Activities in the Celgene Field as set forth in the
Celgene Development Plan/Budget to Develop Licensed Compounds and Licensed
Products in the Celgene Field.
2.1.2.    Celgene Responsibilities. Subject to the oversight of the Joint
Development Committee, Celgene shall be solely responsible for managing all
Celgene Development Activities relating to Licensed Compounds or Licensed
Products. Celgene shall use Commercially Reasonable Efforts to carry out (a) the
Celgene Development Activities as set forth in the Celgene Development
Plan/Budget to Develop Licensed Compounds and Licensed Products in the Celgene
Field and (b) any Celgene Development Activities in the PH Field as set forth in
the PH Field Development Plan/Budget. Celgene shall use Commercially Reasonable
Efforts to Develop and seek Regulatory Approval for Licensed Products in the
Celgene Field in the Major Market Countries.
2.1.3.    Development Plan/Budget.
(a)    Each Celgene Development Plan/Budget shall contain the specific
Development and Manufacturing objectives in the Celgene Field to be achieved by
Celgene during the applicable Contract Year, the specific Development and
Manufacturing objectives in the Celgene Field to be achieved by Acceleron during
the applicable Contract Year, and the timeline for performing such Development
objectives.
(b)    Each PH Field Development Plan/Budget shall contain the specific
Development and Manufacturing objectives in the PH Field to be achieved by each
Party during the applicable Contract Year, and the timeline for performing such
Development objectives.
(c)    Acceleron shall prepare the first draft of the initial PH Field
Development Plan/Budget and present it to Celgene at the first Joint Development
Committee meeting in Contract Year 2018, and the Parties agree that (a)
Acceleron may conduct all PH Field Development Activities that are Acceleron
Development Activities prior to such meeting and (b) Celgene will conduct all PH
Field Development Activities that have been designated in writing previously as
Celgene Development Activities prior to such meeting.
(d)    With the exception of the PH Field Development Plan/Budget for Contract
Year 2018, the Joint Development Committee shall prepare a draft of a revised
Development Plan/Budget for each Development Plan/Budget at least one hundred
twenty (120) days prior to the commencement of any Contract Year. During the
Agreement Term, the Joint Development Committee shall, at least ninety (90) days

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prior to the commencement of any Contract Year during the Agreement Term,
approve and submit to the Parties each revised Development Plan/Budget. At any
time during the Agreement Term, the Joint Development Committee may approve
amendments to a Development Plan/Budget.
2.14.    Payment of Development Costs. Development Costs and other costs
associated with Development shall be allocated as between the Parties in
accordance with Section 5.5.
2.1.5.    Consultation. The Parties agree to consult with each other with
respect to the Development of Licensed Products and Licensed Compounds in
accordance with the provisions of Section 2.9.3.

2.2    Records.
2.2.1.    Generally. Each Party shall, and shall require the Third Parties
performing services for such Party (including Third Party contract research
organizations and service providers) to, maintain scientific records in
sufficient detail and in good scientific manner appropriate for patent and
regulatory purposes, which shall fully and properly reflect all work done and
results achieved in the performance of this Agreement by such Party. Each Party
shall have the right, during normal business hours and upon reasonable notice,
to inspect and copy (or request the other Party to copy) all records of the
other Party maintained in connection with the work done and results achieved in
the performance of this Agreement, but solely to the extent access to such
records is necessary for a Party to exercise its rights under this Agreement;
provided that Acceleron’s access to Celgene records shall be limited to records
of (a) Celgene’s Development Activities for the purpose of supporting Regulatory
Approval in North America and Europe and (b) Celgene’s Development Activities
for the purpose of supporting Regulatory Approval of Sotatercept Licensed
Products in the PH Field in the Territory. All such records and the information
disclosed therein shall be deemed Confidential Information pursuant to Article
9.
2.2.2.    Electronic Records.
(a)    Upon Celgene’s request, Acceleron will provide Celgene reasonable
assistance for Celgene to convert records provided by Acceleron to Celgene into
electronic form. In addition, upon Celgene’s request, Acceleron will use
templates for recordkeeping provided by Celgene reasonably necessary to assist
Celgene in making electronic filings with Regulatory Authorities.
(b)    Upon Acceleron’s request, Celgene will provide Acceleron reasonable
assistance for Acceleron to convert records provided by Celgene to Acceleron
into electronic form. In addition, upon Acceleron’s request, Celgene will use
templates for recordkeeping provided by Acceleron reasonably necessary to assist
Acceleron in making electronic filings with Regulatory Authorities.
2.2.3.    Security. With regard to Confidential Information of the other Party,
each Party shall institute reasonable security precautions and shall use
reasonable efforts to (a) keep physical

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copies of such Confidential Information in locked locations; (b) maintain
electronic copies of such Confidential Information in digitally secured
locations with access permitted on a “need to know” basis; and (c) ensure that
local computers are password protected and programmed to require password entry
after reasonable periods of disuse.

2.3    Regulatory Matters.
2.3.1.    General. Celgene shall be responsible to develop a regulatory strategy
and prepare all submissions, documents or other correspondence to be submitted
to the applicable Regulatory Authorities for Licensed Compounds and Licensed
Products in the Field (other than Sotatercept Licensed Compounds and Sotatercept
Licensed Products in the PH Field) in consultation with the Joint Development
Committee. Acceleron shall be responsible to develop a regulatory strategy and
prepare all submissions, documents or other correspondence to be submitted to
the applicable Regulatory Authorities for Sotatercept Licensed Compounds and
Sotatercept Licensed Products in the PH Field in consultation with the Joint
Development Committee.
2.3.2.    Regulatory Activities in Celgene Field. With respect to all Licensed
Products and Licensed Compounds in the Field (other than Sotatercept Licensed
Compounds and Sotatercept Licensed Products in the PH Field) in the Territory:
(a)    Regulatory Responsibility. Celgene shall oversee, monitor, coordinate,
file, and hold in its name all NDAs, all communications with and submissions to
Regulatory Authorities and all Regulatory Approvals with respect to Licensed
Compounds and Licensed Products. All costs associated with such activities will
be allocated between the Parties in accordance with Article 5, including Section
5.5. If any INDs are filed in Acceleron’s name in connection with any Option
Compound, such IND will be assigned to Celgene at such time, if any, as the
Option Compound is deemed a “Licensed Compound” pursuant to Section 7.2.
(b)    Regulatory Meetings and Correspondence. (i) Celgene shall have primary
responsibility for interfacing, corresponding and meeting with the applicable
Regulatory Authorities and (ii) to the extent practicable, Acceleron shall be
entitled to participate in all meetings and telephonic discussions between
representatives of Celgene and the applicable Regulatory Authorities. For
purposes of clarification of clause (ii) of this Section 2.3.2(b), Celgene
agrees to use Commercially Reasonable Efforts to notify Acceleron of such
planned meetings and telephonic discussions with Regulatory Authorities and to
use Commercially Reasonable Efforts to accommodate the schedule of Acceleron’s
attendees at such meetings or discussions. Celgene shall be entitled to limit,
but not entirely exclude, the number of representatives of Acceleron that attend
such meetings and telephonic discussions with applicable Regulatory Authorities.
2.3.3.    Regulatory Activities in PH Field. Solely with respect to Sotatercept
Licensed Compounds and Sotatercept Licensed Products in the PH Field in the
Territory:

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(a)     Regulatory Responsibility. Acceleron shall oversee, monitor, coordinate
and submit all communications with and submissions to Regulatory Authorities and
all Regulatory Approvals, and all INDs shall be filed in Acceleron or its
designee’s name; provided that in the event that Celgene is required to hold an
NDA for a Sotatercept Licensed Product in the PH Field under Applicable Law, it
will hold in its name such NDA and make, at Acceleron’s reasonable direction,
filings related to such NDAs that have been reviewed and approved by Acceleron
solely to the extent such filings relate to Sotatercept Licensed Compounds or
Sotatercept Licensed Products in the PH Field. To the extent consistent with
Applicable Law, the Parties shall cooperate and take all reasonable action
required to permit Acceleron to hold the NDA for each Sotatercept Licensed
Product in the PH Field.
(b)    Regulatory Meetings and Correspondence. To the extent permitted by
Applicable Law, Acceleron shall have primary responsibility for interfacing,
corresponding and meeting with such Regulatory Authorities. In the event that
Celgene is required by a Regulatory Authority or under Applicable Law to
interface, correspond or meet with a Regulatory Authority with respect to a
Sotatercept Licensed Compound or Sotatercept Licensed Product in the PH Field,
it shall participate in such interaction as reasonably directed by Acceleron (to
the extent such direction is consistent with Applicable Law) and Celgene shall
take all reasonable effort to ensure, including via notice and scheduling
accommodations, that Acceleron is able to participate in all meetings and
telephonic discussions between representatives of Celgene and the applicable
Regulatory Authorities with respect to a Sotatercept Licensed Compound or
Sotatercept Licensed Product in the PH Field.
2.3.4.    Review of Correspondence. Subject to the terms of this Agreement
(including Sections 2.3.2 and 2.3.3), to the extent practicable and to the
extent a Party has the right under this Agreement to submit such documents or
other correspondence, the submitting Party shall provide the other Party with
drafts of any documents or other correspondence to be submitted to the
applicable Regulatory Authorities pertaining to a Licensed Compound or Licensed
Product in the Field in the Territory, sufficiently in advance of submission for
the other Party to review any such submission, and such other Party may comment
on such documents, in which case the submitting Party shall consider in good
faith all such comments. The submitting Party shall provide to the other Party,
as soon as reasonably practicable, copies of any documents or other
correspondence received from Regulatory Authorities pertaining to each Licensed
Compound or Licensed Product (including any meeting minutes).
2.3.5.    Adverse Event Reporting; Safety Concerns; Pharmacovigilance.
(a)    Each Party shall be responsible for complying with all Applicable Laws
governing Adverse Events in any Territory and Celgene shall maintain the global
safety database for Licensed Compounds and Licensed Products in the Field in the
Territory and Acceleron shall provide reasonable assistance to Celgene in its

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maintenance of such global safety database, at each Party’s own expense. Each
Party shall notify the other Party as promptly as reasonably possible (i) after
receiving any notice from a Regulatory Authority, independent review committee,
data safety monitoring board or another similar clinical trial or post-marketing
monitoring body alleging concern regarding a patient safety issue or containing
other material information relevant to the safety or efficacy of a Licensed
Compound or Licensed Product in the Field in the Territory, or (ii) if such
Party determines in good faith that there is a concern regarding a patient
safety issue with respect to a Licensed Compound or Licensed Product in the
Field in the Territory (such notice or determination, a “Safety Concern”).
(b)    Notwithstanding any other provision of this Agreement, with respect to
any Safety Concern, in the event that [* * *] the Safety Concern is [* * *] in
connection with the on-going Development, Manufacture or Commercialization of
Licensed Compounds or Licensed Products in the Field, it may send notice thereof
to [* * *], in which case the Parties shall, to the extent permitted by
Applicable Law and consistent with patient ethical considerations, [* * *] until
such Safety Concern is addressed to [* * *], acting in good faith taking into
account patient safety and the best interests of activities hereunder with
respect to both the Celgene Field and the PH Field.
(c)    The Parties shall in good faith negotiate and agree upon a
pharmacovigilance agreement on customary terms and conditions to be entered into
prior to the use by Acceleron of any Existing Drug Product in any Clinical
Trials.

2.4    Manufacture and Supply.
2.4.1.    Clinical Supply. Subject to Section 2.4.2, Celgene shall Manufacture
and supply all Clinical Supplies. At Celgene’s request, Acceleron shall assist
Celgene in obtaining a second source for supply of Clinical Supplies in order to
supply Celgene with Clinical Supplies for the Phase 2B Clinical Trials.
2.4.2.    Supply of Sotatercept Licensed Products for Clinical Trials in the PH
Field. As of the Amended and Restated Effective Date, Celgene or its Affiliates
have, in their possession, certain quantities of Sotatercept Drug Product
(“Existing Drug Product”). Existing Drug Product shall (i) be used by the
Parties for any Clinical Trials for Licensed Products in the Field and (ii) be
allocated, by mutual agreement, for use between the Parties based on each
Party’s reasonably anticipated need for Licensed Product for Clinical Trials in
the Field; provided that in no event shall Acceleron receive fewer than [* * *]
of Existing Drug Product at [* * *] (or an equivalent amount if provided in a
different vial strength). With respect to any Clinical Trials to be initiated by
Acceleron, its Affiliate or Sublicensee, subject to the foregoing allocation,
Celgene shall deliver Existing Drug Product for such Clinical Trials to
Acceleron or its designee at no cost to Acceleron (except as otherwise provided
in this Section 2.4.2) at a location selected by Acceleron and notified in
writing to Celgene (the “Delivery Location”) within [* * *] days of Acceleron’s
request(s) for such Existing Drug Product, such requests to be made at
Acceleron’s reasonable discretion; provided that

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Acceleron shall be responsible for shipping and insurance costs reasonably
incurred by Celgene in the shipment and delivery of Existing Drug Product to the
Delivery Location pursuant to this Agreement. With respect to Existing Drug
Product provided by Celgene to Acceleron hereunder, title and risk of loss shall
transfer from Celgene to Acceleron upon transfer by Celgene to a shipping agent
selected by Acceleron at the location(s) at which Existing Drug Product is
stored by or on behalf of Celgene. Celgene hereby warrants to Acceleron that
Existing Drug Product supplied under this Section 2.4.2 shall be Manufactured in
accordance with the applicable specifications for such Existing Drug Product
submitted to the FDA by Celgene (and not rejected by the FDA thereafter) and
cGMP. The Parties shall meet no later than [* * *] to discuss the Parties’
future Clinical Supply needs in addition to the Existing Drug Product, including
a CMC analysis with respect thereto. If Celgene elects to Manufacture
Sotatercept Drug Product after exhaustion of the Existing Drug Product, the
Parties shall negotiate in good faith the terms of a supply agreement (the
“Clinical Supply Agreement”) for the supply by Celgene to Acceleron of
Sotatercept Drug Product for Development of Sotatercept Licensed Products in the
PH Field. The Clinical Supply Agreement shall provide: (i) that Celgene shall
use Commercially Reasonable Efforts to Manufacture and supply to Acceleron or
its designee Sotatercept Drug Product for Development of Sotatercept Licensed
Products in the PH Field at a price equal to [* * *] of Celgene’s Fully Loaded
Cost to Manufacture such Sotatercept Drug Product (such price constituting
Development Costs to be allocated in accordance with Section 5.5) and (ii) for
such other terms and conditions as are reasonable and customary for similar
clinical supply agreements in the pharmaceutical industry. In the event that (a)
despite having used good faith commercially reasonable efforts, the Parties are
unable to reach agreement on the terms of a Clinical Supply Agreement by
[* * *], or (b) Celgene elects not to Manufacture Sotatercept Drug Product after
the Existing Drug Product has been exhausted, then Acceleron shall have the
right to Manufacture Clinical Supplies of Sotatercept Licensed Compounds and
Sotatercept Licensed Products for the Development of Sotatercept Licensed
Products in the PH Field, in which case Celgene shall use good faith efforts to
assist Acceleron in securing a source of supply for such Clinical Supplies and
shall use Commercially Reasonable Efforts to cause those CMOs engaged by Celgene
in the Manufacture of Sotatercept Licensed Compounds and Sotatercept Licensed
Products to provide a technology transfer in accordance with Applicable Laws and
industry standards to Acceleron or its designee of manufacturing processes and
Know-How to the extent necessary to Manufacture Sotatercept Licensed Compounds
and Sotatercept Licensed Products for use in Clinical Trials in the PH Field;
provided that, with respect to any CMO, to the extent not permitted or provided
for in the agreement(s) with such CMO, such transfer shall be subject to such
CMO’s consent. The cost of any technology transfer pursuant to this Section
2.4.2 shall be borne equally by the Parties.
2.4.3.    Commercial Supply. Subject to the other provisions of this Section
2.4.3, Celgene shall Manufacture and supply all Commercial Supplies. Within [* *
*] after initiation of a Phase 3 Clinical Trial of a Sotatercept Licensed
Product in the PH Field by Acceleron, its Affiliate or Sublicensee, if Celgene
elects to Manufacture Sotatercept Drug Product for Commercialization of
Sotatercept Licensed Products in the PH Field, the Parties shall negotiate in
good faith the terms of a supply agreement (the “Commercial Supply

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Agreement”) for the supply by Celgene to Acceleron of Sotatercept Drug Product
for Commercialization of Sotatercept Licensed Products in the PH Field. The
Commercial Supply Agreement shall provide: (i) that Celgene shall use
Commercially Reasonable Efforts to Manufacture and supply to Acceleron or its
designee Sotatercept Drug Product for Commercialization of Sotatercept Licensed
Products in the PH Field at a price equal to [* * *] of Celgene’s Fully Loaded
Cost to Manufacture such Sotatercept Drug Product, and (ii) for such other terms
and conditions as are reasonable and customary for similar commercial supply
agreements in the pharmaceutical industry. In the event that, (a) despite having
used good faith commercially reasonable efforts, the Parties are unable to reach
agreement on the terms of a Commercial Supply Agreement within [* * *] following
initiation of a Phase 3 Clinical Trial of a Sotatercept Licensed Product in the
PH Field by Acceleron, its Affiliate or Sublicensee or (b) Celgene elects not to
Manufacture Sotatercept Drug Product for Commercialization of Licensed Products
in the PH Field, Acceleron shall have the right to Manufacture Commercial
Supplies of Sotatercept Licensed Compounds and Sotatercept Licensed Products for
Commercialization in the PH Field, in which case Celgene shall use good faith
efforts to assist Acceleron in securing a source of supply for such Commercial
Supplies and shall, and shall use Commercially Reasonable Efforts to cause those
CMOs engaged by Celgene in the Manufacture of Sotatercept Licensed Compounds and
Sotatercept Licensed Products to, provide a technology transfer in accordance
with Applicable Laws and industry standards to Acceleron or its designee of
manufacturing processes and Know-How to the extent necessary to Manufacture
Sotatercept Licensed Compounds and Sotatercept Licensed Products for
Commercialization in the PH Field; provided that, with respect to any CMO, to
the extent not permitted or provided for in the agreement(s) with such CMO, such
transfer shall be subject to such CMO’s consent. The cost of any technology
transfer pursuant to this Section 2.4.3 shall be borne equally by the Parties.
2.4.4.    U.S. Manufacture. To comply with United States government regulations
for the licensing of federally funded inventions, Celgene, its Affiliates and
any Sublicensees will commit that Licensed Products covered by the Salk Patent
Rights sold in the United States will be Manufactured substantially in the
United States to the extent required by Applicable Law. Notwithstanding the
foregoing, during the Agreement Term, upon Celgene’s request, Acceleron agrees
to seek a waiver from the United States government with respect to the
requirement that Licensed Products for sale in the United States be manufactured
substantially in the United States. Celgene understands that Acceleron cannot
guarantee that such waiver can be obtained.
2.4.5.    Manufacturing Generally. All Clinical Supplies and Commercial Supplies
will be Manufactured in accordance with GLP and GMP, as applicable, and
Applicable Law. In addition, the Manufacturing process used for Clinical
Supplies and Commercial Supplies shall be in accordance with the IND, NDA, or
other Regulatory Approval, as applicable, for the Licensed Product or Licensed
Compound. In addition, at no cost to Celgene, Acceleron shall make its personnel
reasonably available for meetings or teleconferences to support and assist
Celgene in the Manufacture of the Licensed Product or Licensed Compound.

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2.5    Commercialization Plan/Budget. The Joint Commercialization Committee, no
later than [* * *] months prior to the anticipated commercial launch of the
first Licensed Product and thereafter no later than [* * *] of each Contract
Year, shall approve a strategic commercialization plan for the Licensed Products
in the Field in the Territory (the “Commercialization Plan/Budget”) which sets
forth the matters agreed upon by the Joint Commercialization Committee. The
Joint Commercialization Committee shall prepare the initial Commercialization
Plan/Budget no later than [* * *] months prior to the anticipated commercial
launch of the first Licensed Product in the Field in the Territory. Thereafter,
the Joint Commercialization Committee shall prepare a draft of such
Commercialization Plan/Budget no later than [* * *] of each Contract Year. The
Joint Commercialization Committee will consider including (but is not required
to include) (a) a multi-year marketing strategy that includes plans for market
research, health economics, pricing and reimbursement, medical affairs and value
added initiatives, (b) a multi-year communications strategy that includes plans
for public relations, conferences and exhibitions, and other external meetings,
internal meetings and communications, publications and symposia, internet
activities, and core brand package, (c) a multi-year strategy for Post-Approval
Clinical Trials and lifecycle management activities, (d) a high level operating
plan for the implementation of such strategies on an annual basis, including
information related to product positioning, core messages to be communicated,
share of voice requirements and pricing strategies, (e) a commercially
reasonable level of detailing activity, (f) a commercialization budget, and (g)
all other activities to be conducted in connection with the Commercialization of
the Licensed Products in the Field in the Territory.

2.6    Commercialization.
2.6.1.    Subject to Sections 2.6.2 and 2.7.2, (a) Acceleron shall be
responsible for Commercialization activities relating to Sotatercept Licensed
Compounds and Sotatercept Licensed Products in the PH Field in the Territory in
accordance with the Commercialization Plan/Budget approved by the JCC and (b)
Celgene shall be solely responsible for all other Commercialization activities
relating to Licensed Compounds and Licensed Products in the Field in the
Territory.
2.6.2.    [* * *] shall be the “Distributing Party” for all Licensed Products in
the Field in the Territory except where, at the time of the first BLA meeting
with the applicable Regulatory Authority with respect to a Sotatercept Licensed
Product, the Parties have mutually determined that [* * *] in the Celgene Field
and PH Field, respectively, in which case, then [* * *] shall be the
“Distributing Party” for such Sotatercept Licensed Product in the [* * *] Field
and [* * *] shall be the “Distributing Party” for such Sotatercept Licensed
Product in the [* * *] Field. Acceleron and Celgene shall coordinate efforts to
facilitate the creation of [* * *] for the Sotatercept Licensed Products in the
PH Field and the Licensed Products in the Celgene Field.
2.6.3.    The Distributing Party or its designee for a Subfield will book all
sales, and manage the sale, invoicing and distribution system, of Licensed
Products in such Subfield in the Territory in accordance with the
Commercialization Plan/Budget; provided that a Distributing Party can only
designate an Affiliate or Sublicensee as a designee for such activities and, in
the event a Party is a Distributing Party for the other Party’s Subfield under

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this Agreement, any such designee must also perform similar services for
Licensed Products in the Distributing Party’s Subfield.

2.7    Commercialization Activities in the Celgene Field.
2.7.1.    Commercialization Outside North America. Celgene shall use
Commercially Reasonable Efforts to Commercialize the Licensed Products in the
Celgene Field in each country outside North America in which Regulatory Approval
for a Licensed Product is obtained.
2.7.2.    Co-Promotion of Licensed Products in the Celgene Field Within North
America. Celgene and Acceleron shall Commercialize Licensed Products in the
Field (other than Sotatercept Licensed Products in the PH Field) in North
America in accordance with the Commercialization Plan/Budget as follows:
(a)    Commercialization Activities. Within North America, the Parties will use
Commercially Reasonable Efforts to Commercialize such Licensed Products in the
Celgene Field. In addition, within North America, the Parties will use
Commercially Reasonable Efforts to conduct the Commercialization activities
assigned to them pursuant to the Commercialization Plan/Budget, including the
performance of detailing in accordance therewith. In conducting the
Commercialization activities, the Parties will comply with all Applicable Laws,
applicable industry professional standards and compliance policies of Celgene
which have been previously furnished to Acceleron, as the same may be updated
from time to time and provided to Acceleron. Celgene will reasonably assist
Acceleron in training sales representatives in such standards. Neither Party
shall make any claims or statements with respect to such Licensed Products in
the Celgene Field that are not strictly consistent with the product labeling and
the sales and marketing materials approved for use pursuant to the
Commercialization Plan/Budget.
(b)    Sales Representatives. The Commercialization Plan/Budget will set forth
the number of physicians to be called on, call frequency and other matters
necessary to determine the detailing effort to be utilized for Promotion in the
Celgene Field in North America pursuant to the Agreement. The Commercialization
Plan/Budget will allocate to each Party its portion of the total detailing
effort for the aggregate of all such Licensed Products across all indications in
the Celgene Field in North America; provided that, unless otherwise agreed to by
the Parties, (i) Acceleron will be allocated at least [* * *] sales
representatives in the United States for the Promotion of such Licensed Products
directed to [* * *] and (ii) Acceleron will be allocated approximately [* * *]
of the detailing effort in each country in North America directed to [* * *] and
any other prescribing physicians that are not [* * *]. The Joint
Commercialization Committee will attempt to provide that Acceleron’s assigned
detailing efforts are distributed geographically within North America in a
manner reasonably consistent with the distribution of the U.S. population, the
Canadian population, and the Mexican population and that each Party’s detailing
effort will be directed to physicians of similar prescribing potential. The
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Acceleron will be reimbursed pursuant to a rate set forth in the
Commercialization Plan/Budget.
(c)    Sales Force. The Joint Commercialization Committee shall determine the
number of sales representatives needed to carry out the required detailing
effort in the Celgene Field. Each Party, in its sole discretion, shall create a
field management structure for its sales effort. Each sales representative shall
have a sales territory that allows such sales representative to perform a
reasonable number of details within a reasonable geographic area (i.e., without
overly-burdensome travel requirements). The effort of the Acceleron and Celgene
sales forces in Promoting Licensed Products in the Celgene Field will be
organized under the supervision of the Joint Commercialization Committee as to
qualifications of sales representatives and field-based sales managerial
personnel and the timing of hiring in light of the then-current
Commercialization Plan/Budget; provided that the Commercialization Plan/Budget
shall identify the portion of the detailing effort to be undertaken by Acceleron
no later than [* * *] months before the planned date of the NDA submission. At
least [* * *] of Acceleron’s sales force planned to be available upon launch of
such Licensed Product in the Celgene Field shall be hired no later than [* * *]
before the PDUFA date, and Acceleron’s sales force shall be trained within [* *
*] of hiring.
(d)    Training Materials and Sessions. The Joint Commercialization Committee
will develop Licensed Product-specific training materials for the Celgene Field
and arrange for provision of such materials to each Party’s sales forces. The
Joint Commercialization Committee will develop a sales training program directed
towards such Licensed Products in the Celgene Field. Unless otherwise mutually
agreed by the Parties, Celgene and Acceleron sales representatives will
participate jointly in a launch meeting for each Licensed Product in the Celgene
Field, which shall include training sessions of Licensed Product-specific sales
skills with respect to the approved indications for the Licensed Products in the
Celgene Field. Subsequent to launch, Celgene and Acceleron shall periodically
hold meetings with Acceleron and Celgene field management (down to and including
district managers or their equivalents who are directly supervising territory
sales representatives) to coordinate Promotion of the Licensed Products in the
Celgene Field. As requested by Acceleron, Celgene shall make its management,
marketing, training and other personnel reasonably available to participate in
Acceleron’s national and regional sales meetings and Licensed Product-training
events.
(e)    Promotional Materials. Celgene, at its sole cost and expense, shall
provide Acceleron with sales and promotional materials sufficient to permit
Acceleron to perform detailing calls in the Celgene Field in a manner consistent
with the detailing calls performed by the Celgene sales force. With respect to
such Licensed Products in the Celgene Field, Acceleron’s sales representatives
will utilize only those sales and promotional materials provided to them by
Celgene and will not utilize any other materials relating to or referring to the
Licensed Product.

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(f)    Termination of Acceleron Sales Force Cost Reimbursement. On a Licensed
Product-by-Licensed Product and country-by-country basis in North America, on
the date on which in such country there is at least one Generic Product with
respect to such Licensed Product in the Celgene Field, then Celgene shall no
longer be responsible for Acceleron’s Sales Force Costs under Section 5.5.1(a)
(or Section 2.7.2(b)) with respect to such Licensed Product in such country in
North America, and such Sales Force Costs will no longer be deemed Operating
Costs hereunder, and Acceleron shall have no further obligation to Promote such
Licensed Product in the Celgene Field or maintain a sales force for the purpose
of Promoting such Licensed Product in the Celgene Field.

2.8    Third Parties.
2.8.1.    The Parties shall be entitled to utilize the services of Third
Parties, including Third Party contract research organizations and service
providers to perform their respective Development, Manufacturing and
Commercialization activities; provided that any such utilization in the Celgene
Field in North America of a Third Party (except as provided in Section 2.8.2)
shall be subject to the advance notice and approval of the Joint Development
Committee or Joint Commercialization Committee; provided further that Acceleron
shall not be permitted to utilize Third Parties for Acceleron’s
Commercialization activities except with respect to Commercialization activities
for a Sotatercept Licensed Product in the PH Field; provided further, that in no
event will Acceleron use a contract sales organization in connection with its
Commercialization activities for a Sotatercept Licensed Product in the PH Field
without the prior written consent of Celgene, such consent not to be
unreasonably withheld or delayed; provided further that each Party shall remain
at all times fully liable for its respective responsibilities under each
Development Plan/Budget, Commercialization Plan/Budget and this Agreement;
provided further that any Third Party that Manufactures on behalf of either
Party must comply with GMP and be approved or qualified by the applicable
Regulatory Authority.
2.8.2.    Notwithstanding Section 2.8.1, the advance notice and approval of the
Joint Development Committee shall not be required in respect of the use of the
Third Parties previously engaged by Acceleron under an agreement entered into
prior to the Effective Date and set forth on Schedule 2.8; provided that such
exception shall only apply to any services that are currently being provided
under such agreements (whether pursuant to the agreements themselves or any work
orders entered into in connection therewith), and Acceleron shall not be
entitled to enter into new work orders or request additional services under such
agreements without complying with the advance notice and approval of the Joint
Development Committee.
2.8.3.    Any agreement with a Third Party to perform a Party’s responsibilities
under this Agreement shall include confidentiality and non-use provisions which
are no less stringent than those set forth in Article 9 of this Agreement.

2.9    Information Sharing.

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2.9.1.    Tech Transfer. Within 30 days of Celgene’s request, Acceleron, at no
cost to Celgene, shall commence the transfer to Celgene of relevant Acceleron
Technology necessary for Celgene to perform its obligations or exercise its
rights hereunder and will use Commercially Reasonable Efforts to complete such
transfer in a timely fashion. In addition, at no cost to Celgene, Acceleron
shall make its personnel reasonably available for meetings or teleconferences to
support and assist Celgene in the Development, Manufacture, and
Commercialization of the Licensed Product or Licensed Compound. Within thirty
(30) days of Acceleron’s request, Celgene, at no cost to Acceleron, shall permit
Acceleron to access relevant Celgene Technology licensed to Acceleron pursuant
to Section 4.2.
2.9.2.    Reports By Both Parties. Each Party shall keep the Joint Development
Committee or the Joint Commercialization Committee fully informed about the
status of the activities performed pursuant to each Development Plan/Budget,
including providing the Joint Development Committee with copies of the final
form of all written reports that relate to such activities, or pursuant to the
Commercialization Plan/Budget, as applicable. From time to time during the
Agreement Term, Acceleron shall provide Celgene with access to any Acceleron
Technology in order to permit Celgene to perform its obligations or exercise its
rights hereunder. From time to time during the Agreement Term, Celgene shall
provide Acceleron with access to any Celgene Technology in order to permit
Acceleron to exercise its rights hereunder with respect to Sotatercept Licensed
Compounds and Sotatercept Licensed Products in the PH Field in the Territory.
2.9.3.    Meetings. [* * *] on dates and times mutually agreed by the Parties,
Acceleron may, at its option, send at least one Acceleron representative to meet
with the Celgene product team(s) responsible for the Development and regulatory
activities for each Licensed Product and to discuss the conduct and progress of,
and plans for, the Development and regulatory affairs with respect to such
Licensed Product.

2.10    ACE-536 Agreement. Subject to the next sentence, Celgene, in its sole
discretion, may decide (a) to develop and commercialize a “Licensed Compound” or
“Licensed Product” under the ACE-536 Agreement (as defined below) instead of
Developing and Commercializing a Licensed Compound or Licensed Product under
this Agreement or (b) following the Completion of the Acceleron Phase 2 Clinical
Trials (as each such term is defined in the ACE-536 Agreement), to Develop a
Licensed Compound or Licensed Product hereunder instead of a “Licensed Compound”
or “Licensed Product” under the ACE-536 Agreement, and, thereafter, if Celgene
is undertaking “Development” or “Commercialization” (each as defined in the
ACE-536 Agreement) activities in accordance with the ACE-536 Agreement with
respect to a “Licensed Compound” or “Licensed Product” thereunder, Celgene will
be deemed to be in compliance with any Development or Commercialization
obligations under this Agreement. Celgene acknowledges that a decision to pursue
the scenario described in subsection (b) will not be made based primarily on
Celgene’s payment obligations to Acceleron under this Agreement or the ACE-536
Agreement, but rather will take into consideration such things as the resources
as would normally be exerted or employed by a similarly-situated
biopharmacecutical company, product life, stage of development, safety and
efficacy, development costs, operating costs, the anticipated prescription
label, the nature of the product, the clinical setting in which the product is
expected to be used, competitiveness of the

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marketplace, regulatory environment, the patent or other proprietary position of
the product, and other clinical, commercial, regulatory or manufacturing
conditions then prevailing.

Article 3
COLLABORATION MANAGEMENT

3.1    Joint Development Committee.
3.1.1.    Establishment. Under the Amended Agreement, the Parties have
established a joint development committee to facilitate Development of Licensed
Compounds and Licensed Products during the Agreement Term (the “Joint
Development Committee”).
3.1.2.    Membership. Unless otherwise agreed by the Parties, the Joint
Development Committee shall be comprised of three (3) representatives from each
Party with one (1) representative with relevant decision-making authority from
each Party such that the Joint Development Committee is able to effectuate all
of its decisions within the scope of its responsibilities as set forth in
Section 3.1.5 below. Either Party may replace or substitute its respective
representatives to the Joint Development Committee at any time with prior notice
to the other Party, provided that such replacement or substitute is of
comparable authority within that Party. Upon mutual agreement of the Parties,
additional representatives or consultants may be invited to attend a Joint
Development Committee meeting, subject to such representatives’ and consultants’
written agreement to comply with the requirements of Article 9. Each Party shall
bear its own expenses relating to attendance at such meetings by its
representatives.
3.1.3.    Chairperson. The Chairperson of the Joint Development Committee (the
“JDC Chairperson”) shall alternate between Acceleron’s representative and
Celgene’s representative on a Contract Year basis. The JDC Chairperson’s
responsibilities shall include (a) scheduling meetings; (b) setting agendas for
meetings with solicited input from the representatives of the Party who does not
have a sitting JDC Chairperson; (c) preparing and confirming minutes of the
meetings, which shall provide a description in reasonable detail of the
discussions held at the meeting and a list of any actions, decisions or
determinations made by the Joint Development Committee and delivering minutes to
each Party’s senior management for review and final approval; and (d) conducting
meetings.
3.1.4.    Meetings. The Joint Development Committee shall meet in accordance
with a schedule established by mutual written agreement of the Parties, at least
once per [* * *] (and more frequently as the Joint Development Committee
determines is necessary to fulfill its responsibilities), with the location for
such meetings alternating between Acceleron’s facilities and Celgene’s
facilities (or such other locations as are determined by the Joint Development
Committee). Alternatively, if the Parties agree, the Joint Development Committee
may meet by means of teleconference, videoconference or other similar
communications equipment. In connection with any transition of responsibilities
from Acceleron to Celgene (including the transition of Manufacturing
responsibility), the Joint Development Committee shall meet and discuss how best
to transition such responsibilities to Celgene and, in connection with
Manufacturing responsibility, shall establish a supply

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transition plan with respect to the applicable Licensed Product. Acceleron shall
cooperate fully to assist in transitioning to Celgene all applicable
responsibilities.
3.1.5.    Responsibilities. The Joint Development Committee shall have the
following responsibilities:
(a)    reviewing and approving (i) each annual Development Plan/Budget in
accordance with the time frames set forth in Section 2.1.3 and (ii) any proposed
modifications to such Development Plan/Budget;
(b)    developing a publication strategy for Development activities and results
arising out of this Agreement;
(c)    facilitating the transfer of Know-How and Confidential Information
between the Parties for purposes of conducting each Development Plan/Budget;
(d)    reviewing the progress of the Parties in their conduct of each
Development Plan/Budget against the timelines and budgets contained therein, as
applicable, reviewing relevant data and considering issues of priority;
(e)    approving the licensing of Third Party technology, as described in
Section 5.6.3(c);
(f)    performing such other activities as are contemplated under this Agreement
and that the Parties mutually agree shall be the responsibility of the Joint
Development Committee; and
(g)    defining a target Licensed Product profile after consultation with the
Parties’ respective commercial managers.

3.2    Joint Commercialization Committee.
3.2.1.    Establishment. Under the Amended Agreement, the Parties have
established a joint commercialization committee to facilitate Commercialization
of Licensed Compounds and Licensed Products during the Agreement Term (the
“Joint Commercialization Committee”).
3.2.2.    Membership. Unless otherwise agreed by the Parties, the Joint
Commercialization Committee shall be comprised of three (3) representatives from
each Party with one (1) representative with relevant decision-making authority
from each Party such that the Joint Commercialization Committee is able to
effectuate all of its decisions within the scope of its responsibilities as set
forth in Section 3.2.5 below. Either Party may replace or substitute its
respective representatives to the Joint Commercialization Committee at any time
with prior notice to the other Party, provided that such replacement or
substitute is of comparable authority within that Party. Upon mutual agreement
of the Parties, additional representatives or consultants may be invited to
attend a Joint Commercialization Committee meeting, subject to such
representatives’ and consultants’ written agreement to comply with the

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requirements of Article 9. Each Party shall bear its own expenses relating to
attendance at such meetings by its representatives. In the event that that
Acceleron ceases to continue to appoint members of the Joint Commercialization
Committee, Celgene shall deliver all notices of activities of the Joint
Commercialization Committee and materials relating to Commercialization of
Licensed Products to the Vice President of Sales & Marketing of Acceleron; and,
notwithstanding Acceleron's lack of membership on the Joint Commercialization
Committee, Acceleron shall remain obligated to perform its obligations hereunder
with respect to the Commercialization of Licensed Products and comply with the
instructions of Celgene on behalf of the Joint Commercialization Committee, as
provided herein.
3.2.3.    Chairperson. The Chairperson of the Joint Commercialization Committee
(the “JCC Chairperson”) shall alternate between Acceleron’s representative and
Celgene’s representative on a Contract Year basis, with the first JCC
Chairperson being the representative of the Party that has, or whose Affiliate
or Sublicensee has, been the first Party or Affiliate or Sublicensee of a Party
to initiate a Phase 3 Clinical Trial for a Licensed Compound or Licensed Product
in the Field in the Territory. The JCC Chairperson’s responsibilities shall
include (a) scheduling meetings; (b) setting agendas for meetings with solicited
input from the representatives of the Party that does not then have a
representative as JCC Chairperson; (c) preparing and confirming minutes of the
meetings, which shall provide a description in reasonable detail of the
discussions held at the meeting and a list of any actions, decisions or
determinations made by the Joint Commercialization Committee and delivering
minutes to each Party’s senior management for review and final approval; and (d)
conducting meetings.
3.2.4.    Meetings. The Joint Commercialization Committee shall meet in
accordance with a schedule established by mutual written agreement of the
Parties, at least once per [* * *] (and more frequently as the Joint
Commercialization Committee determines is necessary to fulfill its
responsibilities), with the location for such meetings alternating between
Acceleron’s facilities and Celgene’s facilities (or such other locations as are
determined by the Joint Commercialization Committee); provided that, unless
otherwise agreed to by the Parties, the Joint Commercialization Committee shall
not be required to meet earlier than the time necessary to complete the
activities contemplated by Section 2.5. Alternatively, if the Parties agree, the
Joint Commercialization Committee may meet by means of teleconference,
videoconference or other similar communications equipment.
3.2.5.    Responsibilities. The Joint Commercialization Committee shall have the
following responsibilities:
(a)    establishing the strategy for the Commercialization of Licensed Products
in the Celgene Field and PH Field;
(b)    developing and approving the Commercialization Plan/Budget in accordance
with Section 2.5, as well as updating the Commercialization Plan/Budget and
amending the Commercialization Plan/Budget from time to time as appropriate;

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(c)    subject to the specific terms and conditions hereof, allocating
responsibilities under the Commercialization Plan/Budget to the Parties in
accordance with the Parties’ abilities to perform such activities in the most
efficient and cost effective manner;
(d)    overseeing the implementation of the strategy for Commercializing the
Licensed Products in the Field (including strategies related to regulatory
approvals, reimbursement, advertising and promotion, brand integrity, sales, and
launch sequence as set forth in the Commercialization Plan/Budget);
(e)    providing input to the Joint Development Committee regarding the target
product profile for the Licensed Products and making recommendations regarding
changes to the same;
(f)    approving the licensing of Third Party technology, as described in
Section 5.6.3(c);
(g)    reviewing the Parties’ marketing and promotional activities in the
Territory to ensure that such activities are consistent with the
Commercialization Plan/Budget;
(h)    determining a [* * *] strategy for Licensed Products in the Field in
Territory with the objective of [* * *], subject to Applicable Law, the [* * *]
for Licensed Products in the Field in the Territory;
(i)    at any time, if any, that each Party is, pursuant to the terms of this
Agreement, Commercializing a Sotatercept Licensed Product in its Subfield
[* * *], determining, on at least an annual basis, the [* * *] of such
Sotatercept Licensed Product between the PH Field and the Celgene Field in the
Territory, including on a country-by-country or region-by-region basis as
decided by the JCC, for the purpose for determining [* * *] under this
Agreement; and
(j)    performing such other activities as are contemplated under this Agreement
and that the Parties mutually agree shall be the responsibility of the Joint
Commercialization Committee.

3.3    Joint Responsibilities of the Joint Development Committee and Joint
Commercialization Committee. In addition to the independent Joint Development
Committee and Joint Commercialization Committee meetings, the Joint Development
Committee and the Joint Commercialization Committee shall coordinate to hold
joint meetings as appropriate to discuss issues which are relevant to both
Development and Commercialization, including in order to: (i) establish the
target product profile for the Licensed Products (including indications for
which the Licensed Products will be Developed and Commercialized, key labeling
claims required for commercial success of the Licensed Products given the
competitive environment, and any other key product features and benefits which
will be used to Develop or support a promotional message or reimbursement status
for the Licensed Products), (ii) discuss development of the Licensed Product for
additional indications and alternative delivery forms, (iii) discuss development
of improvements

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in formulation, presentation and other features of Licensed Products considered
desirable for life cycle management and maximizing sales of the Licensed
Products, and (iv) set the end point criteria to determine whether a Clinical
Trial or other Development activity is deemed successful. Such joint meetings
may be held by videoconference, teleconference or in person and any decisions
required to be taken shall be submitted to the Joint Development Committee or
Joint Commercialization Committee for resolution in accordance with the terms
hereof.

3.4    Appointment of Subcommittees and Project Teams. The Joint Development
Committee and Joint Commercialization Committee may each create such
subcommittees or project teams as such committee deems necessary to carry out
its responsibilities, including subcommittees focused on certain regions in the
Territory that, with respect to a particular region, have the same attributes
and scope of responsibilities as the relevant parent committee has with respect
to the Territory. Each such subcommittee and project team shall report
recommendations and proposed actions to the Joint Development Committee or Joint
Commercialization Committee, as applicable, which shall approve or reject such
recommendations or actions proposed in accordance with the terms of this
Agreement.

3.5    Decision-Making.
3.5.1.    The Joint Development Committee and Joint Commercialization Committee
shall each act by unanimous agreement of its members, with each Party having one
vote. If the Joint Development Committee or Joint Commercialization Committee,
after [* * *] (or such other period as the Parties may otherwise agree) of good
faith efforts to reach a unanimous decision on an issue, fails to reach such a
unanimous decision, then either Party may submit such dispute to the senior
management of Celgene and Acceleron for review.
3.5.2.    Notwithstanding the foregoing, none of Celgene, Acceleron, the Joint
Development Committee and the Joint Commercialization Committee may make any
decision inconsistent with the express terms of this Agreement without the prior
written consent of each Party.

3.6    Dispute Resolution. With respect to any disputes between the Parties that
are subject to the oversight of the Joint Development Committee or the Joint
Commercialization Committee, if the dispute cannot be resolved within [* * *]
following escalation to senior management pursuant to Section 3.5.1, then either
Party may refer the matter to the Executive Officers to be resolved by
negotiation in good faith as soon as is practicable, but in no event later than
[* * *] after such referral. Such resolution, if any, by the Executive Officers
shall be final and binding on the Parties. If the Executive Officers are unable
to resolve such dispute within such [* * *] period, then Celgene shall have the
final tie-breaking vote, except that (i) Acceleron shall have the final
tie-breaking vote with respect to any disputes pertaining to matters relating
solely to the PH Field (other than Celgene Development Activities and matters
relating to pricing of a Licensed Product) and (ii) in the event of a dispute
relating to the determination of the ratio split of Net Sales pursuant to
Section 3.2.5(i) or pricing of a Licensed Product, such dispute shall be
resolved by consensus of the Parties and the status quo with respect to such
matter shall remain until the Parties mutually agree otherwise.

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3.7    Dissolution. The Joint Development Committee and Joint Commercialization
Committee shall each be dissolved upon expiration of the Agreement Term, or
earlier upon mutual written agreement of the Parties.

3.8    Appointment of Joint Development Committee and Joint Commercialization
Committee Members. Notwithstanding the above, at all times after [* * *] years
from the Effective Date, Acceleron’s membership and participation on the Joint
Development Committee, the Joint Commercialization Committee, and any related
subcommittees shall be at Acceleron’s sole option. If, after [* * *] years from
the Effective Date, Acceleron does not appoint members of the Joint Development
Committee or the Joint Commercialization Committee, it shall not be a breach of
this Agreement, and, thereafter, Celgene shall, in its own sole discretion, make
all decisions for, and take all actions for, the Joint Development Committee or
Joint Commercialization Committee, as applicable, pursuant to the terms and
conditions of this Agreement, and Acceleron shall comply with all such decisions
of Celgene.

Article 4
LICENSES, GRANTS OF RIGHTS AND INTELLECTUAL PROPERTY OWNERSHIP

4.1    License Grants to Celgene. Subject to the terms and conditions of this
Agreement, Acceleron hereby grants to Celgene and its Affiliates during the
Agreement Term an exclusive, royalty-bearing license (which shall, however, be
(a) subject to Acceleron’s retained rights set forth in Section 4.3 and (b)
co-exclusive with Acceleron solely to permit Acceleron to perform the Acceleron
Development Activities, Manufacturing responsibilities, and co-Promotion
activities to the extent provided herein) under the Acceleron Technology and
Acceleron’s interest in the Joint Technology to offer for sale, sell, make, have
made, use and import (including to Develop, Manufacture and Commercialize)
Licensed Compounds and Licensed Products in the Field in the Territory.

4.2    License Grant to Acceleron. Subject to the terms and conditions of this
Agreement, Celgene hereby grants Acceleron during the Agreement Term (a) an
exclusive, royalty-bearing (pursuant to Section 5.7) license under the Celgene
Technology and Celgene’s interest in the Joint Technology to offer for sale,
sell, make and have made (subject to Section 2.4.2 and Section 2.4.3), use and
import Sotatercept Licensed Compounds and Sotatercept Licensed Products in the
PH Field in the Territory, and (b) a non-exclusive royalty-free license under
the Celgene Technology solely to perform its Development and co-Promotion
obligations pursuant to the Development Plan/Budget and Commercialization
Plan/Budget, as applicable, and to Manufacture Sotatercept Licensed Compounds
and Sotatercept Licensed Products in accordance with Section 2.4.2 and Section
2.4.3.

4.3    Retained Rights of Acceleron. Notwithstanding anything to the contrary in
Section 4.1 or this Agreement, Acceleron shall retain the exclusive (even as to
Celgene, except to the extent required for Celgene to perform activities for the
benefit of Acceleron as set forth in this Agreement) right

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on behalf of itself, its Affiliates and its Sublicensees and licensees to
Develop, and Commercialize, and to the extent set forth in Section 2.4.2 and
Section 2.4.3, Manufacture, Sotatercept Licensed Compounds and Sotatercept
Licensed Products in the PH Field in the Territory.

4.4    Sublicenses.
4.4.1.    Celgene’s Right to Sublicense. Celgene may sublicense the rights
granted to it under Section 4.1, in whole or in part, through one or more tiers
to one or more of its Affiliates or Third Parties at any time; provided,
however, that the sublicense, to the extent it involves the sublicense of any
Salk Patent Rights, will be subject to the terms and conditions of Section 2.2
of the Salk License. In the event that Celgene enters into any sublicense (other
than a sublicense to an Affiliate) that includes North America as a territory,
in whole or in part, then, such sublicense shall not modify Acceleron’s right to
participate in Collaboration matters as provided in Article 2 (Collaboration)
and Article 3 (Collaboration Management) or under the cost sharing provisions of
Section 5.5. Celgene shall remain responsible for the performance of its
Sublicensees under this Agreement, including for all payments due hereunder,
whether or not such payments are made by Celgene, its Affiliates or its
Sublicensees. Celgene shall provide Acceleron with notice and a copy of each
sublicense, and any modification or termination thereof, promptly (and in any
event within [* * *] days after such agreement has been fully executed) after
execution of such sublicense, modification or termination; provided that any
such copy may be redacted to remove any confidential, proprietary or competitive
information of Celgene or its Sublicensee, but such copy shall not be redacted
to the extent that it impairs Acceleron’s or Salk’s ability to ensure compliance
with this Agreement or the Salk License, as applicable. All such notices and
copies of sublicenses provided by Celgene under this Section 4.4.1 shall be
deemed to be Confidential Information of Celgene subject to the provisions of
Article 9 hereof whether or not so marked.
4.4.2.    Acceleron’s Right to Sublicense/License. Subject to Section 4.8,
Acceleron may sublicense the rights granted to it under clause (a) of Section
4.2 and license the rights retained by it under Section 4.3, in whole or in
part, through one or more tiers to one or more of its Affiliates or Third
Parties at any time. Acceleron shall remain responsible for the performance of
its Sublicensees under this Agreement, including for all payments due hereunder,
whether or not such payments are made by Acceleron, its Affiliates or its
Sublicensees. Acceleron shall provide Celgene with notice and a copy of each
sublicense or license, as applicable, and any modification or termination
thereof, promptly (and in any event within [* * *] days after such agreement has
been fully executed) after execution of such sublicense, license, modification
or termination; provided that any such copy may be redacted to remove any
confidential, proprietary or competitive information of Acceleron or its
Sublicensee, but such copy shall not be redacted to the extent that it impairs
Celgene’s ability to ensure compliance with this Agreement. All such notices and
copies of sublicenses or licenses provided by Acceleron under this Section 4.4.2
shall be deemed to be Confidential Information of Acceleron subject to the
provisions of Article 9 hereof whether or not so marked.

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4.4.3.    Terms. Each sublicense granted by a Party pursuant to Sections 4.4.1
or 4.4.2 shall be subject and subordinate to the terms and conditions of this
Agreement and shall contain terms and conditions consistent with those in this
Agreement. Agreements with any Commercializing Sublicensee shall contain the
following provisions: (a) a requirement that such Sublicensee submit applicable
sales or other reports consistent with those required hereunder; (b) an audit
requirement similar to the requirement set forth in Section 5.8.4; and (c) a
requirement that such Sublicensee comply with the confidentiality and non-use
provisions of Article 9 with respect to both Parties’ Confidential Information.
4.4.4.    Effect of Termination. Except as otherwise provided in the sublicense
agreement, if this Agreement terminates for any reason with respect to rights
that a Party has sublicensed pursuant to this Section 4.4, any Sublicensee of a
Party shall, from the effective date of such termination, automatically become a
direct licensee of the other Party with respect to the rights originally
sublicensed to the Sublicensee by the sublicensing Party; provided, however,
that such Sublicensee is not in breach of its sublicense agreement and continues
to perform thereunder. Notwithstanding the foregoing, the licensor Party under
this Section 4.4.4 shall not be liable to such Sublicensee with respect to any
obligations of the sublicensing Party to the Sublicensee.

4.5    Right of Reference.
4.5.1.    Acceleron hereby grants Celgene, its Affiliates and its Sublicensees a
right of reference with respect to clinical, regulatory and other data
(including CMC data) and information that is Controlled by Acceleron as of the
Amended and Restated Effective Date or Controlled by Acceleron following the
Amended and Restated Effective Date during the Agreement Term that is necessary
or useful for the submission, approval or maintenance of Regulatory Approvals to
Develop, Manufacture or Commercialize Licensed Compounds or Licensed Products in
the Celgene Field in the Territory (except for Sotatercept Licensed Compounds or
Sotatercept Licensed Products in the PH Field).
4.5.2.    Celgene hereby grants Acceleron, its Affiliates and its licensees and
Sublicensees a right of reference with respect to clinical, regulatory and other
data (including CMC data) and information that is Controlled by Celgene as of
the Amended and Restated Effective Date or Controlled by Celgene following the
Amended and Restated Effective Date during the Agreement Term that is necessary
or useful for the submission, approval or maintenance of Regulatory Approvals to
Develop, Manufacture or Commercialize Sotatercept Licensed Compounds or
Sotatercept Licensed Products in the PH Field in the Territory.
4.5.3.     Each Party shall require its Sublicensees to grant to it a
transferable right of reference to all data and information (including
Regulatory Submissions for Products) that, if Controlled by such Party, would be
granted by such Party as part of the right of reference granted under Section
4.5.1 or 4.5.2, as applicable, so that such Party can grant the other Party, its
Affiliates and its Sublicensees the right of reference set forth in Section
4.5.1 or 4.5.2, as applicable, with respect to such data and information.

4.6    Ownership of and Rights to Intellectual Property.

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4.6.1.    Ownership of Improvements/Collaboration IP. Each Party agrees promptly
to disclose to the other Party all Improvements and all Collaboration IP made by
or under authority of such Party under this Agreement. As between the Parties,
(a) title to all Celgene Improvements and Celgene Collaboration IP shall be
owned by Celgene, (b) title to all Acceleron Improvements and Acceleron
Collaboration IP shall be owned by Acceleron, and (c) title to all Joint
Improvements and Joint Collaboration IP shall be jointly owned by Celgene and
Acceleron. Acceleron hereby assigns, and Acceleron shall cause its employees,
consultants, and agents to assign, its right, title, and interest in and to all
Celgene Improvements to Celgene.
4.6.2.    Joint Improvements/Collaboration IP. Subject to the rights herein,
each Party shall have the right to practice and exploit Joint Improvements and
Joint Collaboration IP, without any obligation to account to the other for
profits, or to obtain any approval of the other Party to license, assign or
otherwise exploit Joint Improvements and Joint Collaboration IP, by reason of
joint ownership thereof, and each Party hereby waives any right it may have
under the laws of any jurisdiction to require any such approval or accounting;
and to the extent there are any Applicable Laws that prohibit such a waiver,
each Party will be deemed to so consent. Each Party agrees to be named as a
party, if necessary, to bring or maintain a lawsuit involving a Joint
Improvement or Joint Collaboration IP.
4.6.3.    Data. All data generated in the course of Clinical Trials hereunder
shall be owned by Celgene and deemed “Celgene Know-How” and Acceleron hereby
assigns, and Acceleron shall cause its employees, consultants, and agents to
assign, its right, title, and interest in and to such data and information to
Celgene; provided that data generated in the course of Clinical Trials following
the Amended and Restated Effective Date during the Agreement Term for
Sotatercept Licensed Compounds and Sotatercept Licensed Products in the PH Field
shall be owned by Acceleron.
4.6.4.    Celgene IP. Celgene is and shall remain the sole owner of the Celgene
Technology.
4.6.5.    Acceleron IP. Acceleron is and shall remain the sole owner of the
Acceleron Technology.
4.6.6.    Disputes as to Inventorship and Ownership of Improvements and
Collaboration IP. Should the Parties fail to agree regarding inventorship of any
invention made in the conduct of activities under this Agreement or the
ownership of Improvements and Collaboration IP arising out of this Agreement,
the Parties shall refer the matter to a mutually agreed-upon outside counsel for
resolution. All determinations of inventive contribution for inventions arising
hereunder shall be determined under United States patent law. The Parties agree
that each of the individuals listed on Schedule 4.6.6 are acceptable outside
counsel for such resolution, and neither Party will use such individuals (or the
law firms for whom such individuals work) for any legal services without the
prior written consent of the other Party. The costs of such outside counsel
shall be borne equally by the Parties.

4.7    Salk License.

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4.7.1.    Acknowledgement. Except as provided in Section 4.7.2, Acceleron
acknowledges that it is responsible for the fulfillment of its obligations under
the Salk License and agrees to fulfill the same, including any provisions
necessary to maintain in effect any rights sublicensed to Celgene hereunder and
the exclusive nature of such rights, subject to Celgene’s compliance with its
obligations hereunder. In the event of any conflict between the terms of this
Agreement and the Salk License, the Parties will discuss in good faith how to
address the conflict; provided that, if the Parties are unable to agree on how
to address the conflict, the terms of this Agreement shall govern.
Notwithstanding the foregoing, Celgene acknowledges that (i) the Salk License
limits Acceleron from sublicensing under the Salk Patent Rights of any right
with regard to Secondary Licensed Products (as defined in the Salk License),
other than a sublicense of a Primary Licensed Product (including a Primary
Licensed Product that subsequently becomes a Secondary Licensed Product) or in
connection with a sublicense of a Secondary Licensed Product that is first
discovered or identified by Acceleron, and (ii) the licenses under the Salk
License are limited to therapeutic products, and diagnostic products are only
permitted with respect to Secondary Licensed Products. Celgene further
acknowledges that the Salk License provides for the right of Salk to (a)
Prosecute the Salk Patent Rights and (b) make and use, and to permit others at
academic, government and non-profit institutions to make and use, the Salk
Patent Rights. Celgene additionally acknowledges that the Salk Patent Rights
supported by federal funding are subject to certain obligations to the United
States government as provided in the Salk License.
4.7.2.    Incorporation of Certain Provisions. Celgene acknowledges and agrees
that it shall be bound by the following provisions of the Salk License, as if
Celgene was a “Licensee” thereunder: [* * *]; provided that, with respect to
Section [* * *], the Parties acknowledge that, as provided in Exhibit A to the
Salk License, no “Biological Materials” have been provided to Acceleron, and
Acceleron will not request or accept any “Biological Materials” from Salk
without Celgene’s prior written consent (which consent may be conditioned on,
among other things, confirmation that the “Biological Materials” license under
the Salk License is sublicensable to Celgene); provided further that,
notwithstanding Celgene’s agreement to be bound by Section [* * *] of the Salk
License, as between Acceleron and Celgene, the obligation to indemnify Salk
pursuant to such section will be allocated between Acceleron and Celgene in
accordance with Section 11.7 hereof. The Parties acknowledge that [* * *] has
been provided to Celgene, except [* * *].
4.7.3.    Covenants Regarding the Salk License. Acceleron agrees that during the
Agreement Term:
(a)    Acceleron shall not modify or amend the Salk License in any way that
could adversely affect Celgene’s rights or economic interest under this
Agreement without Celgene’s prior written consent;
(b)    Acceleron shall not terminate the Salk License in whole or in part,
without Celgene’s prior written consent, if such termination would affect
Celgene’s license granted hereunder;

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(c)    Acceleron shall be solely responsible for, and shall make, all royalty,
milestone, and other payments owed to Salk pursuant to the Salk License;
(d)    Acceleron shall not exercise or fail to exercise any of Acceleron’s
rights or obligations under the Salk License that relate to the Licensed
Compounds, Licensed Products, or Celgene’s rights hereunder (including the right
to negotiate with Salk with respect to “Inventions” under Section 2.4 of the
Salk License), in each case, without the prior written consent of Celgene, not
to be unreasonably withheld; and, at the reasonable request of Celgene,
Acceleron shall exercise such rights and make such requests as are permitted
under the Salk License;
(e)    Acceleron shall promptly furnish Celgene with copies of all reports and
other communications that Acceleron furnishes to Salk that relate to the subject
of this Agreement;
(f)    Acceleron shall promptly furnish Celgene with copies of all reports and
other communications that Acceleron receives from Salk that relate to the
subject of this Agreement;
(g)    Acceleron shall furnish Celgene with copies of all notices received by
Acceleron relating to any alleged breach or default by Acceleron under the Salk
License within [* * *] after Acceleron’s receipt thereof; in addition, if
Acceleron should at any time breach the Salk License or become unable to timely
perform its obligations thereunder, Acceleron shall immediately notify Celgene;
(h)    If Acceleron cannot or chooses not to cure or otherwise resolve any
alleged breach or default under the Salk License, Acceleron shall so notify
Celgene within [* * *] of such decision, which shall not be less than [* * *]
prior to the expiration of the cure period under the Salk License; provided that
Acceleron shall use Commercially Reasonable Efforts to cure any such breach or
default; and
(i)    Celgene, in its sole discretion, shall be permitted [* * *] in accordance
with the terms and conditions of the Salk License or otherwise [* * *]; and, if
Celgene [* * *].
4.7.4.    Survival of Celgene’s Rights. As provided in Section 2.2 and
10.3(a)(iv) of the Salk License, in the event of termination of the Salk
License, Celgene’s rights hereunder will survive in accordance with the terms of
such sections. The Parties agree that [* * *], without Celgene’s prior written
consent, shall be deemed a material breach of this Agreement by Acceleron;
provided that (a) if [* * *], Celgene agrees to use Commercially Reasonable
Efforts to assist Acceleron in [* * *], and (b) if [* * *], such [* * *] shall
not be deemed a material breach by Acceleron of this Agreement.

4.8    Right of First Negotiation.

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4.8.1.    Acceleron hereby grants to Celgene the exclusive right of first
negotiation as set forth in this Section 4.8, with respect to the grant of
exclusive rights to Develop, Commercialize and, subject to Section 2.4.2 and
Section 2.4.3, Manufacture Sotatercept Licensed Compounds and Sotatercept
Licensed Products in the PH Field in the Territory.
4.8.2.    During the time period following the Amended and Restated Effective
Date and during the Agreement Term, Acceleron will not directly or indirectly,
license, transfer, sell or otherwise grant to any Third Party any right to [* *
*] (the “Restricted Activities”) unless permitted pursuant to Section 4.8.3 or
unless such Third Party is a distributor or other Third Party acting on behalf
of Acceleron or any of its Affiliates. In the event Acceleron wishes to conduct
any Restricted Activities not permitted pursuant to this Section 4.8, Acceleron
shall notify Celgene in writing, such notice to be accompanied by (a) a written
report of any [* * *] undertaken by Acceleron or its Affiliates with respect to
the [* * *] and a summary in reasonable detail of the [* * *], aggregated or
otherwise resulting from such [* * *] and (b) the proposed scope of the
Restricted Activities it wishes to conduct (such notice and accompanying
information, the “ROFN Notice” and such Restricted Activities set forth in the
ROFN Notice, the “ROFN Activities”). Celgene shall have [* * *] from receipt of
such written notice to notify Acceleron in writing if Celgene would like to
exercise its right of first negotiation with respect to the ROFN Activities.
Upon any exercise by Celgene of such right, the Parties shall enter into
exclusive good faith negotiations for a period no longer than [* * *] (unless
extended upon mutual agreement of the Parties) regarding the terms and
conditions of an agreement granting Celgene rights to conduct the ROFN
Activities.
4.8.3.    If, with respect to any ROFN Activities, (a) the Parties fail to
execute a definitive agreement that grants Celgene rights to conduct such ROFN
Activities within the [* * *] period set forth in Section 4.8.2 or any longer
period agreed to by the Parties, (b) the Parties otherwise mutually agree in
writing to terminate such negotiations, or (c) Celgene fails to exercise its
right of first negotiation within the [* * *] period set forth in Section 4.8.2
(or Celgene indicates in writing that it elects not to exercise such right),
then Acceleron shall be permitted to engage in the ROFN Activities [* * *];
provided that, in the event the Parties do not reach agreement with respect to
the ROFN Activities as a result of (a), (b) or (c) above, then, for [* * *]
thereafter, Acceleron shall be permitted to undertake the proposed ROFN
Activities without again complying with this Section 4.8, provided, that
Acceleron shall not, during such [* * *] period, offer, agree to grant or grant
a Third Party more favorable terms in the aggregate than those last offered to
Celgene (from the licensee’s perspective) for comparable rights to conduct such
ROFN Activities [* * *] unless it has offered such terms to Celgene and Celgene
has not agreed in writing, within [* * *] of Acceleron’s offer to Celgene, to
negotiate in good faith a definitive agreement with Acceleron on such terms for
such rights. In the event Celgene does agree to such terms within such [* * *]
period, the Parties shall enter into good faith negotiations regarding the
additional terms and conditions of an agreement granting Celgene rights to
conduct the ROFN Activities on such agreed-upon terms for the shorter of (x) [*
* *], (y) until the Parties either mutually agree to terminate such negotiations
or execute the definitive agreement or (z) until Celgene notifies Acceleron in
writing that it elects to not enter into such definitive agreement. For purposes
hereof “more favorable terms” with respect to financial terms for such ROFN

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Activities means that the value of the aggregate terms offered to the Third
Party exceed the value of the aggregate terms last offered to Celgene by more
than [* * *] percent [* * *], with such value determined based on the
risk-adjusted net present value of the applicable terms.

4.8    No Other Rights. Except as otherwise provided in this Agreement, neither
Party shall obtain any ownership interest or other right in any Know-How or
Patent Rights owned or Controlled by the other Party.

Article 5
FINANCIAL PROVISIONS

5.1    Upfront Payments. Acceleron hereby acknowledges and agrees that Celgene
made the following payments to Acceleron within ten (10) days of the Effective
Date: (i) thirty-five million dollars ($35,000,000) as an upfront,
non-creditable, non-refundable fee, relating to the license grants set forth in
Article 4, and (ii) ten million dollars ($10,000,000) as an upfront,
non-creditable, non-refundable fee, relating to the option program set forth in
Article 7.

5.2    ActRIIA Development Milestones. For any Licensed Compound or Licensed
Product containing ActRIIA, Celgene shall pay to Acceleron the amounts set forth
below no later than [* * *] days after the earliest date on which the
corresponding milestone event has first been achieved with respect to a Licensed
Compound or Licensed Product in each indication in the Celgene Field described
below:

Milestone Event
Payment for Each Indication in the Celgene Field
 
Oncology
Non-Oncology
Dosing the first patient in the first Phase 2B Clinical Trial for the purposes
of obtaining Regulatory Approval in the United States
N/A
$7,000,0001
Dosing the first patient in the first Phase 3 Clinical Trial for the purposes of
obtaining Regulatory Approval in the United States
$10,000,000
$10,000,000
[* * *]
$[* * *]
$[* * *]
[* * *]
$[* * *]
$[* * *]
[* * *]
$[* * *]
$[* * *]
[* * *]
$[* * *]
$[* * *]
[* * *]
$[* * *]
$[* * *]
[* * *]
$[* * *]
$[* * *]

1 As of the Amended and Restated Effective Date, this milestone payment has been
paid by Celgene to Acceleron.

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A Clinical Trial or NDA will fall within the oncology indication if the Licensed
Compound or Licensed Product is used (a) to treat a patient for cancer or (b) to
treat a patient for a disease, disorder, or condition that results from the
patient having, or being treated for, cancer. All other Clinical Trials or NDAs
will fall within the non-oncology indication. For example, use of a Licensed
Compound or Licensed Product to treat [* * *] will be deemed to fall within the
oncology indication, and, for purposes of this Agreement, the treatment of
anemia in a patient with [* * *] will be considered oncology and will be deemed
to fall within the oncology indication; on the other hand, [* * *] not caused by
any oncologic condition or treatment thereof will fall within the non-oncology
indication (whether or not the patients taking the Licensed Compound or Licensed
Product has cancer or a disease, disorder, or condition that results from the
patient having, or being treated for, cancer). For the avoidance of doubt, a
single Clinical Trial or NDA shall not trigger an obligation by Celgene to pay
milestones with respect to both the oncology and non-oncology indications but
instead shall be treated as falling only within one indication or the other and
requiring not more than one milestone payment; provided that, if the Parties
initially elect one indication (e.g., oncology) to apply to a Licensed Compound
or Licensed Product but later determine it is not effective for that indication,
the Parties may then elect to proceed with the other indication (e.g.,
non-oncology) for such Licensed Compound or Licensed Product; however,
notwithstanding the last sentence of the next paragraph, such Licensed Compound
or Licensed Product shall only trigger milestones in the new indication (in this
example, non-oncology) that occur after such election and shall not trigger any
earlier milestones in the new indication.
For clarity, the milestone payments set forth in this Section 5.2 shall be paid
only once for each indication, regardless of how many Licensed Compounds and
Licensed Products may achieve the milestone event and regardless of whether the
same Licensed Compound or Licensed Product achieves the milestone event for the
same indication more than once. By way of a nonlimiting example, if a Licensed
Compound and a Licensed Product achieve the same milestone event in the same
indication, only one payment is due. Furthermore, to the extent a Licensed
Compound or Licensed Product fails and a replacement Licensed Compound or
Licensed Product is selected, any milestones previously paid for such failed
Licensed Compound or Licensed Product shall not be paid a second time with
respect to such replacement Licensed Compound or Licensed Product. Except as
provided in the prior paragraph, to the extent that any prior milestone has not
been paid at the time of achievement of a subsequent milestone, then upon the
achievement of such subsequent milestone all preceding unpaid milestone payments
shall be made in addition to the payment corresponding to the milestone that has
been achieved; provided that the acceptance or approval of [* * *] shall not be
deemed to trigger any milestone payment for [* * *] in any other country or
jurisdiction.
For purposes of determining the occurrence of milestones under this Section 5.2
and Section 5.3, [* * *] shall be deemed to have occurred [* * *] days following
[* * *]; provided that, if such [* * *], such [* * *] shall not be deemed to
have occurred until such comments have been addressed to the satisfaction of [*
* *].
The Parties agree that, effective as of the execution of the First Amendment to
this Agreement, Celgene shall have no obligations to pay any amounts due
pursuant to the provisions of Section 5.2 of the Original Agreement (including
the table of milestones set forth therein) prior to such

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REQUEST.  REDACTED MATERIAL IS MARKED WITH [* * *] AND HAS BEEN FILED SEPARATELY
WITH THE SECURITIES AND EXCHANGE COMMISSION.

amendment, and the provisions of this Section 5.2 (including the table of
milestones set forth herein) will replace such former provisions in their
entirety as of the Amended and Restated Effective Date. Acceleron acknowledges
and agrees that all payments that were due pursuant to the provisions of the
former Section 5.2 of the Original Agreement were paid in full.
For clarity and notwithstanding any other provision of this Agreement, in no
event shall Celgene be obligated to make any milestone payments pursuant to this
Section 5.2 with respect to any Sotatercept Licensed Compound or Sotatercept
Licensed Product in the PH Field.

5.3    Option Compound Development Milestones. Provided that the option in
Article 7 is exercised in full, for a Licensed Compound or Licensed Product
containing an [* * *] Antibody, [* * *] Antibody, or [* * *] Antibody, Celgene
shall also pay to Acceleron the amounts set forth below no later than [* * *]
days after the earliest date on which the corresponding milestone event has
first been achieved with respect to any such Licensed Compound or Licensed
Product (for the avoidance of doubt, the milestones set forth below shall be
payable separately with respect to a Licensed Compound or Licensed Product
containing an [* * *] Antibody, an [* * *] Antibody or a [* * *] Antibody):

Milestone Event
Payment for Each Indication for [* * *] Antibodies, [* * *] Antibodies and [* *
*] Antibodies
 
Oncology
Non-Oncology
[* * *]
$[* * *]
$[* * *]
[* * *]
$[* * *]
$[* * *]
[* * *]
$[* * *
$[* * *]
[* * *]
$[* * *]
$[* * *]
[* * *]
$[* * *]
$[* * *]
[* * *]
$[* * *]
$[* * *]
[* * *]
$[* * *]
$[* * *]
[* * *]
$[* * *]
$[* * *]

The determination of whether a Clinical Trial or NDA falls within the oncology
indication or non-oncology indication will be made in the same manner as
provided in Section 5.2.
For clarity, the milestone payments set forth in this Section 5.3 shall be paid
only once for each indication for a Licensed Compound or Licensed Product the
underlying Licensed Compound of which is an [* * *] Antibody, once for each
indication for a Licensed Compound or Licensed Product the underlying Licensed
Compound of which is an [* * *] Antibody, and once for each indication for a
Licensed Compound or Licensed Product the underlying Licensed Compound of which
is a [* * *] Antibody, regardless of how many Licensed Compounds and Licensed
Products with such Licensed Compound may achieve the milestone event and
regardless of whether the same Licensed Compound or Licensed Product achieves
the milestone event for the same indication more than once. By way of a
nonlimiting example, if an [* * *] Antibody Licensed Compound and a Licensed
Product containing an [* * *] Antibody achieve the same milestone event in the
same indication,

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only one payment is due; if an [* * *] Antibody Licensed Compound and a Licensed
Product containing an [* * *] Antibody achieve the same milestone event in the
same indication, only one payment is due; and if a [* * *] Antibody Licensed
Compound and a Licensed Product containing a [* * *] Antibody achieve the same
milestone event in the same indication, only one payment is due. In addition for
clarity, if an [* * *] Antibody Licensed Compound or Licensed Product achieves a
particular milestone, and an [* * *] Antibody Licensed Compound or Licensed
Product achieves the same milestone, the particular milestone payment will be
made twice, once with respect to the [* * *] Antibody Licensed Compound or
Licensed Product and once with respect to the [* * *] Antibody Licensed Compound
or Licensed Product. Furthermore, to the extent a Licensed Compound or Licensed
Product the underlying Licensed Compound of which is an [* * *] Antibody, [* *
*] Antibody, or [* * *] Antibody fails and a replacement Licensed Compound or
Licensed Product with the same Licensed Compound is selected, any milestones
previously paid for such failed Licensed Compound or Licensed Product shall not
be paid a second time with respect to such replacement Licensed Compound or
Licensed Product. To the extent that any prior milestone has not been paid at
the time of achievement of a subsequent milestone, then upon the achievement of
such subsequent milestone all preceding unpaid milestone payments shall be made
in addition to the payment corresponding to the milestone that has been
achieved; provided that the acceptance or approval of an NDA in any one country
or jurisdiction shall not be deemed to trigger any milestone payment for the
acceptance or approval of an NDA in any other country or jurisdiction.
The Parties agree that, effective as of the execution of the First Amendment to
this Agreement, Celgene shall have no obligations to pay any amounts due
pursuant to the provisions of Section 5.3 of the Original Agreement (including
the table of milestones set forth therein) prior to such amendment, and the
provisions of this Section 5.3 (including the table of milestones set forth
herein) will replace such former provisions in their entirety. Acceleron
acknowledges and agrees that all payments that were due pursuant to the
provisions of the former Section 5.3 of the Original Agreement were paid in
full.

5.4    Ex-North American Sales Milestones. Celgene shall also pay to Acceleron
the amounts set forth below no later than [* * *] days after the earliest date
on which the corresponding milestone event has first been achieved with respect
to each Licensed Product in the Celgene Field:

Milestone Event
Payment
[* * *]
$[* * *]
[* * *
$[* * *]
[* * *]
$[* * *]

For clarity and notwithstanding any other provision of this Agreement, in no
event shall Celgene be obligated to make any milestone payments pursuant to this
Section 5.4 with respect to any Net Sales of Sotatercept Licensed Product in the
PH Field.

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WITH THE SECURITIES AND EXCHANGE COMMISSION.

Once Celgene has made any particular milestone payment under this Section 5.4,
Celgene shall not be obligated to make any payment under this Section 5.4 with
respect to the re-occurrence of the same milestone for the same Licensed Product
(regardless of how many indications the Licensed Product may be approved for).
For making the determinations under this Section 5.4, Celgene Field Net Sales
shall be derived from audited financial statements of Celgene (or the applicable
Affiliate, Sublicensee or Distributing Party or its designee); provided,
however, that Celgene shall use U.S. GAAP to calculate in good faith the Celgene
Field Net Sales derived from any entities that are not audited or have not
completed their audit within [* * *] days after the end of the preceding
Contract Year. For clarity, two dosage forms of a product would constitute the
same Licensed Product; however, any derivatives and modifications of a Licensed
Product are considered distinct Licensed Products, other than modifications that
are limited to changes in the formulation of a Licensed Product (which
formulation modifications would constitute the same Licensed Product).
In the event that, on a Licensed Product-by-Licensed Product basis, a Licensed
Product has received Regulatory Approval in a country only for one or more
indications in either the Celgene Field or the PH Field (and not in indications
in both the Celgene Field and the PH Field), all sales of such Licensed Product
in such country shall be deemed Net Sales of such Licensed Product in the
Celgene Field or the PH Field, respectively. In the event that a Licensed
Product is sold in a country in both the PH Field and the Celgene Field, the JCC
will allocate Net Sales of such Licensed Product in the PH Field and the Celgene
Field pursuant to Section 3.2.5(i).

5.5    Sharing Costs.
5.5.1.    Cost Sharing. The Parties shall be responsible for paying costs as set
forth in this Section.
(a)    Subject to Section 5.5.1(b), Celgene shall be responsible for paying one
hundred percent (100%) of (i) all Development Costs and (ii) all Operating
Costs, in each case incurred on or after the Amended and Restated Effective
Date.
(b)    Acceleron shall be responsible for paying one hundred percent (100%) of
(i) all Development Costs and (ii) all Operating Costs, in each case incurred on
or after the Amended and Restated Effective Date in the conduct of PH Field
Development Activities (including, for clarity, all Celgene Development
Activities described in clause (iii) of the definition thereof).
(c)    Patent Procurement Costs shall be shared in accordance with the
provisions of Section 8.2.4.
(d)    Purchases of capital equipment related to Manufacturing (e.g., the
purchase and qualification of a manufacturing facility or of additional
manufacturing lines) shall not be included in any cost to be shared or allocated
under this Agreement.
5.5.2.    Sharing Mechanics. The payment of costs pursuant to this Agreement
shall be subject to the following:

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(a)    Notwithstanding anything in this Agreement to the contrary, no cost,
expense, amount or sum allocable or chargeable to the Parties’ activities under
this Agreement shall be allocated or charged more than once. Unless otherwise
specifically authorized by the Parties or this Agreement, all costs, expenses,
amounts or sums to be charged or allocated by one Party to the other Party under
this Agreement shall not be so chargeable or allocable unless they are directly
related to this Agreement and the activities to be performed under this
Agreement.
(b)    It is the intention of the Parties that the interpretation of the
definitions related to this Article 5 shall be in accordance with U.S. GAAP
consistently applied in accordance with the applicable Party’s then current
practices. A Party shall promptly make the appropriate adjustments to the
financial information it supplies under this Agreement to reflect changes to the
provisions, including reasonable detail underlying the adjustment, in reporting
results of operation.
(c)    Furthermore, for any costs or expenses in connection with the performance
of its activities hereunder, which are reimbursable by one Party or subject to
cost-sharing between the Parties, if such costs or expenses consist of payments
made by either Party to a Third Party, they shall be charged hereunder at the
respective Party’s actual out-of-pocket cost.
(d)    Notwithstanding anything in this Agreement to the contrary, each Party
shall be solely responsible for all travel costs for such Party’s and its
Affiliates’ and agents’ employees incurred in connection with the performance of
such Party’s obligations hereunder, and no travel-related expenses incurred by
either Party in connection with Development activities hereunder shall be
included in Development Costs or Operating Costs.
5.5.3.    Cost Reporting.
(a)    Development Costs.
(i)    No later than [* * *] Business Days after the end of each Contract
Quarter, (i) Acceleron shall report to Celgene an estimate of Development Costs
(including any Third Party Intellectual Property Costs that are deemed
Development Costs) incurred in the conduct of Development activities in the
Celgene Field by or on behalf of Acceleron and Patent Procurement Costs (for
which reimbursement is required pursuant to Section 8.2.4), in each case
incurred on or following the Amended and Restated Effective Date, and (ii)
Celgene shall report to Acceleron an estimate of Development Costs (including
any Third Party Intellectual Property Costs that are deemed Development Costs)
incurred in the conduct of Development activities in the PH Field by or on
behalf of Celgene and Patent Procurement Costs (for which reimbursement is
required pursuant to Section 8.2.4), in each case incurred on or following the
Amended and Restated Effective Date.

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(ii)    Furthermore, as soon as practicable after the end of each Contract
Quarter, but in any event no later than [* * *] days after the end of each
Contract Quarter, each Party shall report to the other Party actual Development
Costs and Patent Procurement Costs described in Section 5.5.3(a)(i).
(b)    Results of Operations in North America.
(i)    No later than [* * *] Business Days after the end of each Contract
Quarter, (A) each Party shall report to the other Party an estimate of such
Party’s results of operations in North America with respect to all Licensed
Compounds and Licensed Products in the Celgene Field in the Territory related to
the following: (1) aggregate gross invoice prices of all units of Licensed
Product sold; (2) sales returns and allowances; (3) Celgene Field Net Sales; (4)
number of units sold; and (5) in the case of Acceleron, all Sales Force Costs of
Acceleron and any other Operating Costs of Acceleron in North America in the
Celgene Field that are incurred under the Commercialization Plan/Budget (the
costs in this clause (5) collectively, the “Acceleron NA Operating Costs”), (B)
Acceleron shall report to Celgene an estimate of the Operating Costs, if any,
incurred by or on behalf of Acceleron as the Distributing Party of Sotatercept
Licensed Products in the Celgene Field under the Commercialization Plan/Budget
and (C) Celgene shall report to Acceleron an estimate of the Operating Costs, if
any, incurred by or on behalf of Celgene as the Distributing Party of
Sotatercept Licensed Products in the PH Field under the Commercialization
Plan/Budget.
(ii)     Furthermore, as soon as practicable after the end of each Contract
Quarter, but in any event no later than [* * *] days after the end of each
Contract Quarter, each Party shall report to the other Party actual results of
operations in North America in the Celgene Field and actual Operating Costs,
each as described in the prior sentence.
5.5.4.    Expense Limitations.
(a)    Expenses charged by either Party as Development Costs in the other
Party’s Subfield for any Contract Year shall not exceed [* * *] percent [* * *]
of the amount included for the total expenditure in the relevant then-current
Development Plan/Budget for such Subfield.
(b)    The Acceleron NA Operating Costs for any Contract Year shall not exceed
[* * *] percent [* * *] of the amount included for the total expenditure in the
then-current Commercialization Plan/Budget.
(c)    The Operating Costs incurred by any Party as the Distributing Party of a
Sotatercept Licensed Product in the other Party’s Subfield shall not exceed [* *
*]

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percent [* * *] of the amount included for the total expenditure in the
then-current Commercialization Plan/Budget.
(d)    If any of the costs described in Sections 5.5.4(a) through 5.5.4(c) (i.e.
Development Costs in the other Party’s Subfield, Acceleron NA Operating Costs or
Operating Costs in the other Party’s Subfield) are expected to vary by more than
[* * *] percent [* * *] from the amounts budgeted for expenditure during the
Contract Year, the Party responsible for the forecasted variance shall promptly
revise the Development Plan/Budget or Commercialization Plan/Budget, as
applicable, and submit it in writing, with an explanation of the variance and
the reasons therefore, to the other Party. If the Joint Development Committee or
Joint Commercialization Committee, as applicable, agrees in writing that the
revised budget is acceptable then such revised budget shall be incorporated into
the respective Development Plan/Budget or Commercialization Plan/Budget for the
remainder of the Contract Year.
5.5.5.    Reconciliation Statements. In addition to providing the reports
specified and set forth in Section 5.5.3, within [* * *] days following the end
of a Contract Quarter, Celgene shall prepare, in consultation with Acceleron, a
statement showing the calculation of costs to be allocated to each Party
pursuant to this Section 5.5 and the cash settlement required (the
“Reconciliation Statement”). Payments required pursuant to Reconciliation
Statements shall be made by Acceleron or Celgene in the manner set forth in
Section 5.7.5.

5.6    Royalties Payable for Celgene Field Net Sales.
5.6.1.    Royalty Percentages.
(a)    Celgene as the Distributing Party. For sales of Licensed Products in the
Field (other than sales of Sotatercept Licensed Products in the PH Field) in the
Territory for which Celgene is the Distributing Party pursuant to Section 2.6.2,
Celgene shall retain all amounts received for such sales; provided that Celgene
shall pay to Acceleron the following royalty payments on a Licensed
Product-by-Licensed Product basis during the applicable Royalty Term:
(i)    [* * *] percent [* * *] of annual Celgene Field Net Sales in each region
of the Territory during a Contract Year for that portion of the annual Celgene
Field Net Sales in such region that is less than or equal to [* * *];
(ii)    [* * *] percent [* * *] of annual Celgene Field Net Sales in each region
of the Territory during a Contract Year for that portion of the annual Celgene
Field Net Sales in such region that is greater than [* * *] and less than or
equal to [* * *]; and
(iii)    [* * *] percent [* * *] of annual Celgene Field Net Sales in each
region of the Territory during a Contract Year for that portion of the annual
Celgene Field Net Sales in such region that is greater than [* * *];

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provided further that the applicable thresholds above will be determined on a
region-by-region basis with each of the following areas of the Territory treated
as one region: (i) North America and (ii) the rest of the Territory.
(b)    Acceleron as the Distributing Party. For sales of Sotatercept Licensed
Products in the Celgene Field in the Territory for which Acceleron is the
Distributing Party pursuant to Section 2.6.2, Acceleron shall retain all amounts
received for such sales; provided that Acceleron shall pay to Celgene royalty
payments on Celgene Field Net Sales on a Sotatercept Licensed
Product-by-Sotatercept Licensed Product basis during the applicable Royalty Term
at a royalty rate equal to [* * *] that would apply for such Sotatercept
Licensed Product if Celgene was the Distributing Party of such Licensed Product.
By way of illustration, if Acceleron is the Distributing Party for a Sotatercept
Licensed Product in the Celgene Field for which, if Celgene was the Distributing
Party for such Sotatercept Licensed Product, Celgene would pay Acceleron a
royalty of [* * *] percent [* * *] of Celgene Field Net Sales under this
Agreement (e.g., such Celgene Field Net Sales were in the portion of Celgene
Field Net Sales in a region in the Territory that is less than or equal to [* *
*] and no royalty adjustments under this Agreement are then applicable),
Acceleron shall owe Celgene a royalty equal to [* * *] percent [* * *] of
Celgene Field Net Sales of such Sotatercept Licensed Product.
5.6.2.    Cumulative Royalties. The obligation to pay royalties under this
Agreement shall be imposed only once with respect to a single unit of a Licensed
Product.
5.6.3.    Adjustment in Royalty Rates.
(a)    Know-How Only or Generic Competition. On a country-by-country and
Licensed Product-by-Licensed Product basis, upon the earlier to occur of (i) the
date on which the offering for sale, selling, making, having made, using or
importing of a Licensed Product is no longer covered by a Valid Claim of an
Acceleron Patent Right in such country (but such Manufacture, use or sale of a
Licensed Product continues to be covered by Acceleron Know-How) or (ii) the date
on which in such country there are one or more Generic Products, then the
royalty percentage applicable to Celgene Field Net Sales of such Licensed
Product under Section 5.6.1(a) for such Licensed Product in such country shall
be reduced by fifty percent (50%) for the remainder of the Royalty Term.
(b)    Celgene Third Party Licenses. In the event that one or more licenses to
Third Party Intellectual Property are required by Celgene to offer for sale,
sell, make, have made, use or import Licensed Compounds or Licensed Products in
the Celgene Field in the Territory without infringing the Third Party
Intellectual Property (including claims of a pending patent application that are
reasonably expected to issue), then Celgene may offset fifty percent (50%) of
the amount of commercially reasonable royalties or other payments payable by
Celgene to such Third Party (or paid or reimbursed by Celgene pursuant to
Section 5.6.3(c)) with respect to a particular Licensed Product against amounts
Celgene is obligated to pay Acceleron under

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Section 5.4 or Section 5.6.1(a) for such Licensed Product; provided that in no
such event shall any such offset reduce by more than fifty percent (50%) the
payments otherwise due to Acceleron in particular Contract Years; provided
further that on a Licensed Product-by-Licensed Product basis, any Third Party
royalty payments that are not credited against royalties or sales milestones
paid to Acceleron in the Contract Year in which they were accrued shall be
carried forward and credited against royalties or sales milestones payable to
Acceleron in the subsequent Contract Year(s) hereunder until such royalty
credits are completely expended. The calculation of the royalty reduction under
this Section 5.6.3(b) shall be conducted on a country-by-country and Licensed
Product-by-Licensed Product basis. Celgene shall provide Acceleron with notice
and a copy of each such license, and any modification or termination thereof,
promptly (and in any event within [* * *] days after such agreement has been
fully executed) after execution of such license, modification or termination;
provided that any such copy may be redacted to remove any confidential,
proprietary or competitive information of Celgene or its Sublicensee, but such
copy shall not be redacted to the extent that it impairs Acceleron’s ability to
ensure compliance with this Agreement. With respect to any license entered into
by Celgene to Third Party Intellectual Property, Celgene shall use Commercially
Reasonable Efforts to ensure that such Third Party Intellectual Property is
sublicensable to Acceleron to the extent required under this Agreement.
(c)    Third Party Intellectual Property. Acceleron shall not enter into an
agreement with a Third Party to obtain a license under Third Party Intellectual
Property that solely covers the offering for sale, selling, making, having made,
using or importing Licensed Compounds or Licensed Products in the Celgene Field
in the Territory (including rights of a pending patent application that are
reasonably expected to issue) without first offering Celgene the opportunity to
contact such Third Party regarding entering into such agreement directly. With
respect to Third Party Intellectual Property that covers the offering for sale,
selling, making, having made, using or importing Licensed Compounds or Licensed
Products in the Celgene Field in the Territory but also covers Acceleron’s other
products or compounds, Acceleron shall notify the Joint Development Committee or
Joint Commercialization Committee, as applicable, of the Third Party
Intellectual Property (a “Third Party Intellectual Property Notice”). With
respect to such a license for such Third Party Intellectual Property that covers
the offering for sale, selling, making, having made, using or importing Licensed
Compounds or Licensed Products in the Celgene Field in the Territory, Acceleron
may enter into the license for such Third Party Intellectual Property; provided
that, if the Joint Development Committee or Joint Commercialization Committee,
as applicable, determines that such Third Party Intellectual Property should be
part of the Collaboration, then the following shall apply: (i) Acceleron shall
keep Celgene fully informed of the status of the negotiations with the Third
Party and provide Celgene with copies of all draft agreements; (ii) Celgene may
provide comments and suggestions with respect to the negotiation of the
agreement with the Third Party, and Acceleron shall reasonably consider all
comments and suggestions reasonably recommended by Celgene; (iii)

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Acceleron shall use Commercially Reasonable Efforts to ensure that such Third
Party Intellectual Property is sublicensable to Celgene in accordance with the
terms of this Agreement, treating (unless otherwise agreed by the Parties) the
Third Party Intellectual Property as Acceleron Know-How or Acceleron Patent
Rights hereunder and treating the agreement licensing such the Third Party
Intellectual Property in the same way as the Salk License (including as provided
in Section 4.7), except for payment obligations; provided that, if Acceleron is
not able to obtain a license from such Third Party that is sublicensable in
accordance with this clause (iii), then Acceleron shall promptly so notify
Celgene and shall exclude from any such license that Acceleron obtains the
offering for sale, selling, making, having made, using or importing Licensed
Compounds or Licensed Products in the Celgene Field in the Territory, and (iv)
the Parties shall allocate the Third Party Intellectual Property Costs, unless
otherwise agreed, as follows: (x) the Parties shall determine in good faith an
allocation of upfront payments and intellectual property acquisition fees paid
to any such Third Party with respect to Licensed Compounds or Licensed Products
to be treated as either Development Costs or Operating Costs, (y) development
milestone payments owed to such Third Party that are required to be paid as a
result of the Development of Licensed Compounds or Licensed Products shall be
treated as Development Costs, and (z) sales milestone payments and royalties
owed to such Third Party that are required to be paid as a result of sales of
Licensed Products shall be treated as royalties paid to Third Parties pursuant
to Section 5.6.3(b). In the event that Acceleron delivers to Celgene a Third
Party Intellectual Property Notice and pursues a license to the applicable Third
Party Intellectual Property from such Third Party, Celgene will not directly or
indirectly (other than through Acceleron pursuant to this Agreement) pursue a
license to such Third Party Intellectual Property unless (1) Acceleron decides
to not pursue a license to such Third Party Intellectual Property that covers a
Licensed Compound or Licensed Product (in which event, Acceleron will promptly
notify Celgene of such decision), (2) Acceleron notifies Celgene that Acceleron
is not able to obtain a sublicensable license in accordance with clause (iii) of
the third sentence of this Section, or (3) Celgene was already in discussions
with such Third Party prior to Celgene’s receipt of the Third Party Intellectual
Property Notice regarding licensing such Third Party Intellectual Property.
5.6.4.    Reports and Royalty Payments. Within [* * *] days after the beginning
of each Contract Quarter during the Royalty Term, the Distributing Party for
each Licensed Product in the Celgene Field shall deliver to the other Party a
report setting forth for the previous Contract Quarter the following information
on a Licensed Product-by-Licensed Product and country-by-country basis in the
Territory: (a) the gross sales and Celgene Field Net Sales of Licensed Product,
(b) the number of units sold by the Distributing Party or its designee pursuant
to this Agreement, (c) the basis for any adjustments to the royalty payable for
the sale of each Licensed Product and (d) the royalty due hereunder for the
sales of each Licensed Product (the “Royalty Report”). The total royalty due for
the sale of Licensed Products during such Contract Quarter shall be remitted at
the time such report is made. No such

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reports or royalty shall be due for any Licensed Product before the First
Commercial Sale of such Licensed Product.

5.7    Royalties Payable for PH Field Net Sales.
5.7.1.    Royalty Percentages.
(a)    Acceleron as the Distributing Party. For sales of Sotatercept Licensed
Products in the PH Field in the Territory for which Acceleron is the
Distributing Party pursuant to Section 2.6.2, Acceleron shall retain all amounts
received for such sales; provided that, with respect to each Sotatercept
Licensed Product in a country, Acceleron shall pay to Celgene royalty payments
on PH Field Net Sales during the applicable PH Field Royalty Term of such
Sotatercept Licensed Product in such country at a royalty rate equal to [* * *]
percent [* * *] of PH Field Net Sales of such Sotatercept Licensed Product in
such country.
(b)    Celgene as the Distributing Party. For sales of Sotatercept Licensed
Products in the PH Field in the Territory for which Celgene is the Distributing
Party pursuant to Section 2.6.2, Celgene shall retain all amounts received for
such sales; provided that Celgene shall pay to Acceleron royalty payments on PH
Field Net Sales on a Sotatercept Licensed Product-by-Sotatercept Licensed
Product basis and country-by-country basis during the applicable PH Field
Royalty Term at a royalty rate equal to [* * *] for such Sotatercept Licensed
Product in such country if Acceleron was the Distributing Party of such
Sotatercept Licensed Product in the PH Field (as such PH Field Royalty Rate may
be adjusted pursuant to the terms of this Agreement).
5.7.2.    Cumulative Royalties. The obligation to pay royalties under this
Agreement shall be imposed only once with respect to a single unit of a
Sotatercept Licensed Product.
5.7.3.    Adjustment in Royalty Rates.
(a)    Know-How Only or Generic Competition. On a country-by-country and
Sotatercept Licensed Product-by-Sotatercept Licensed Product basis, upon the
earlier to occur of (i) the date on which the offering for sale, selling,
making, having made, using or importing of a Sotatercept Licensed Product is no
longer covered by a Valid Claim of an Acceleron Patent Right or a Celgene Patent
Right in such country (but such Manufacture, use or sale of a Sotatercept
Licensed Product continues to be covered by Acceleron Know-How or Celgene
Know-How) or (ii) the date on which in such country there are one or more
Generic Products with respect to such Sotatercept Licensed Product, then the
royalty percentage applicable to PH Field Net Sales of such Sotatercept Licensed
Product under Section 5.7.1(a) for such Sotatercept Licensed Product in such
country shall be reduced by fifty percent (50%) for the remainder of the PH
Field Royalty Term.
(b)    Acceleron Third Party Licenses. In the event that one or more licenses to
Third Party Intellectual Property are required by Acceleron to offer for sale,
sell,

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make, have made, use or import Sotatercept Licensed Compounds or Sotatercept
Licensed Products in the PH Field in the Territory without infringing the Third
Party Intellectual Property (including claims of a pending patent application
that are reasonably expected to issue), then Acceleron may offset fifty percent
(50%) of the amount of commercially reasonable royalties or other payments
payable by Acceleron to such Third Party (or paid or reimbursed by Acceleron
pursuant to Section 5.6.3(c)) with respect to a particular Sotatercept Licensed
Product in the PH Field against amounts Acceleron is obligated to pay Celgene
under Section 5.7.1(a) for such Sotatercept Licensed Product, provided that in
no such event shall any such offset reduce by more than fifty percent (50%) the
payments otherwise due to Celgene in particular Contract Years; provided further
that on a Sotatercept Licensed Product-by-Sotatercept Licensed Product basis,
any Third Party royalty payments that are not credited against royalties paid to
Celgene in the Contract Year in which they were accrued shall be carried forward
and credited against royalties payable to Celgene in the subsequent Contract
Year(s) hereunder until such royalty credits are completely expended. The
calculation of the royalty reduction under this Section 5.7.3(b) shall be
conducted on a country-by-country and Sotatercept Licensed
Product-by-Sotatercept Licensed Product basis. Acceleron shall provide Celgene
with notice and a copy of each such license, and any modification or termination
thereof, promptly (and in any event within [* * *] days after such agreement has
been fully executed) after execution of such license, modification or
termination; provided that any such copy may be redacted to remove any
confidential, proprietary or competitive information of Acceleron or its
Sublicensee, but such copy shall not be redacted to the extent that it impairs
Celgene’s ability to ensure compliance with this Agreement. With respect to any
license entered into by Acceleron to Third Party Intellectual Property,
Acceleron shall use Commercially Reasonable Efforts to ensure that such Third
Party Intellectual Property is sublicensable to Celgene to the extent required
under this Agreement.
(c)    Third Party Intellectual Property. Celgene shall not enter into an
agreement with a Third Party to obtain a license under Third Party Intellectual
Property that solely covers the offering for sale, selling, making, having made,
using or importing Sotatercept Licensed Compounds or Sotatercept Licensed
Products in the PH Field in the Territory (including rights of a pending patent
application that are reasonably expected to issue) without first offering
Acceleron the opportunity to contact such Third Party regarding entering into
such agreement directly. With respect to Third Party Intellectual Property that
covers the offering for sale, selling, making, having made, using or importing
Sotatercept Licensed Compounds or Sotatercept Licensed Products in the PH Field
in the Territory but also covers Celgene’s other products or compounds
(including Sotatercept Licensed Compounds or Sotatercept Licensed Products
outside of the PH Field), Celgene shall notify the Joint Development Committee
or Joint Commercialization Committee, as applicable, of the Third Party
Intellectual Property (a “PH Field Third Party Intellectual Property Notice”).
With respect to such a license for such Third Party Intellectual Property that
covers the offering for sale, selling, making, having made, using or importing
Sotatercept

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Licensed Compounds or Sotatercept Licensed Products in the PH Field in the
Territory, Celgene may enter into the license for such Third Party Intellectual
Property; provided that, if the Joint Development Committee or Joint
Commercialization Committee, as applicable, determines that such Third Party
Intellectual Property should be part of the Collaboration, then the following
shall apply: (i) Celgene shall keep Acceleron fully informed of the status of
the negotiations with the Third Party and provide Acceleron with copies of all
draft agreements; (ii) Acceleron may provide comments and suggestions with
respect to the negotiation of the agreement with the Third Party, and Celgene
shall reasonably consider all comments and suggestions reasonably recommended by
Acceleron; (iii) Celgene shall use Commercially Reasonable Efforts to ensure
that such Third Party Intellectual Property is sublicensable to Acceleron in
accordance with the terms of this Agreement, treating (unless otherwise agreed
by the Parties) the Third Party Intellectual Property as Celgene Know-How or
Celgene Patent Rights hereunder, except for payment obligations; provided that,
if Celgene is not able to obtain a license from such Third Party that is
sublicensable in accordance with this clause (iii), then Celgene shall promptly
so notify Acceleron and shall exclude from any such license that Celgene obtains
the offering for sale, selling, making, having made, using or importing
Sotatercept Licensed Compounds or Sotatercept Licensed Products in the PH Field
in the Territory, and (iv) the Parties shall allocate the Third Party
Intellectual Property Costs, unless otherwise agreed, as follows: (x) the
Parties shall determine in good faith an allocation of upfront payments and
intellectual property acquisition fees paid to any such Third Party with respect
to Sotatercept Licensed Compounds or Sotatercept Licensed Products in the PH
Field for which Acceleron shall be responsible, (y) development milestone
payments owed to such Third Party that are required to be paid as a result of
the Development of Sotatercept Licensed Compounds or Sotatercept Licensed
Products in the PH Field shall be borne by Acceleron, and (z) sales milestone
payments and royalties owed to such Third Party that are required to be paid as
a result of sales of Sotatercept Licensed Products in the PH Field shall be
treated as royalties paid to Third Parties pursuant to Section 5.7.3(b). In the
event that Celgene delivers to Acceleron a PH Field Third Party Intellectual
Property Notice and pursues a license to the applicable Third Party Intellectual
Property from such Third Party, Acceleron will not directly or indirectly (other
than through Celgene pursuant to this Agreement) pursue a license to such Third
Party Intellectual Property unless (1) Celgene decides to not pursue a license
to such Third Party Intellectual Property that covers a Sotatercept Licensed
Compounds or Sotatercept Licensed Products in the PH Field (in which event,
Celgene will promptly notify Acceleron of such decision), (2) Celgene notifies
Acceleron that Celgene is not able to obtain a sublicensable license in
accordance with clause (iii) of the third sentence of this Section, or (3)
Acceleron was already in discussions with such Third Party prior to Acceleron’s
receipt of the PH Field Third Party Intellectual Property Notice regarding
licensing such Third Party Intellectual Property.

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5.7.4.    Reports and Royalty Payments. Within [* * *] days after the beginning
of each Contract Quarter during the PH Field Royalty Term, the Distributing
Party for each Licensed Product in the PH Field shall deliver to the other Party
a report setting forth for the previous Contract Quarter the following
information on a Sotatercept Licensed Product-by-Sotatercept Licensed Product
and country-by-country basis in the PH Field in the Territory: (a) the gross
sales and PH Field Net Sales of Sotatercept Licensed Product, (b) the number of
units sold by the Distributing Party or its designee pursuant to this Agreement,
(c) the basis for any adjustments to the royalty payable for the sale of each
Sotatercept Licensed Product and (d) the royalty due hereunder for the sales of
each Sotatercept Licensed Product (the “PH Field Royalty Report”). The total
royalty due for the sale of Licensed Products during such Contract Quarter shall
be remitted at the time such report is made. No such reports or royalty shall be
due for any Licensed Product before the First Commercial Sale of such
Sotatercept Licensed Product.

5.8    Payment Provisions Generally.
5.8.1.    Taxes and Withholding. If laws, rules or regulations require
withholding of income taxes or other taxes imposed upon payments set forth in
Section 5.6, the Party making payments to the other Party under this Agreement
(the “Paying Party”) shall make such withholding payments as required and
subtract such withholding payments from the payments set forth in Section 5.6.
The Paying Party shall submit appropriate proof of payment of the withholding
taxes to the Receiving Party within a reasonable period of time. At the request
of the Party receiving payments from the other Party under this Agreement (the
“Receiving Party”), the Paying Party shall give the Receiving Party such
reasonable assistance, which shall include the provision of appropriate
certificates of such deductions made together with other supporting
documentation as may be required by the relevant tax authority, to enable the
Receiving Party to claim exemption from such withholding or other tax imposed or
obtain a repayment thereof or reduction thereof and shall upon request provide
such additional documentation from time to time as is reasonably required to
confirm the payment of tax.
5.8.2.    Payment and Currency Exchange.
(a)    All amounts (including all costs sharing) payable and calculations
hereunder shall be in United States dollars and shall be paid by bank wire
transfer in immediately available funds to such bank account as may be
designated in writing by Acceleron or Celgene, as applicable, from time to time.
Whenever for the purposes of calculating the royalties payable under Section 5.6
or the costs payable under Section 5.5 conversion from any foreign currency
shall be required, all amounts shall first be calculated in the currency of sale
or currency of incurrence and then converted into United States dollars by
applying the average monthly rate of exchange listed in the New York edition of
The Wall Street Journal for the final month of the applicable Contract Quarter.
(b)    Where royalty amounts are due for Celgene Field Net Sales or PH Field Net
Sales in a country where, for reasons of currency, tax or other regulations,
transfer

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of foreign currency out of such country is prohibited, the Paying Party has the
right to place the Receiving Party’s royalties in a bank account in such country
in the name of and under the sole control of the Receiving Party; provided,
however, that the bank selected be reasonably acceptable to the Receiving Party
and that the Paying Party inform the Receiving Party of the location, account
number, amount and currency of money deposited therein. After the Receiving
Party has been so notified, those monies shall be considered as royalties duly
paid to the Receiving Party and will be completely controlled by the Receiving
Party.
(c)    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 due on Celgene Field Net Sales or PH Field Net Sales shall be suspended
for as long as such prohibition is in effect and as soon as such prohibition
ceases to be in effect, all royalties that the Paying Party would have been
under an obligation to transmit or deposit but for the prohibition shall
forthwith be deposited or transmitted, to the extent allowable.
5.8.3.    Records. Each Party shall keep and maintain accurate and complete
records which are relevant to costs, expenses, sales and payments throughout the
Territory used to determine payments to be made under this Agreement, and such
records shall be maintained for a period of three (3) years from creation of
individual records for examination at the other Party’s expense by an
independent certified public accountant selected by the other Party as described
in Section 5.8.4. A Party’s right to complete a final audit upon termination or
expiration of this Agreement shall expire one year after such termination or
expiration. Any records or accounting information received from the other Party
shall be Confidential Information of the disclosing Party for purposes of
Article 9 of this Agreement. Results of any such audit shall be provided to both
Parties, subject to Article 9 of this Agreement.
5.8.4.    Audits and Interim Reviews.
(a)    Subject to the provisions of Section 5.8.3, either Party may request that
a nationally recognized, independent accounting firm to be mutually agreed upon
by the Parties, which is not either Party’s independent accounting firm, perform
an audit or interim review of the other Party’s books as they relate to this
Agreement in order to express an opinion regarding such Party’s accounting for
revenues, costs and expenses, as applicable, under this Agreement. Such audits
or review shall be conducted at the expense of the requesting Party.
(b)    Upon [* * *] Business Days’ prior written notice from a Party (the
“Auditing Party”), the other Party (the “Audited Party”) shall permit such
accounting firm to examine the relevant books and records of the Audited Party,
including any Affiliates, as may be reasonably necessary to verify the reports
and information submitted by the Audited Party and the accuracy of any Royalty
Report, PH Field Royalty Report or Reconciliation Statement. An examination by a
Party under this Section 5.8.4 (whether of the Audited Party or its Affiliates)
shall [* * *] and shall be limited to the pertinent books and records for any
Contract Year ending not more

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than [* * *] months before the date of the request. The accounting firm shall be
provided access to such books and records at the Audited Party’s facility(ies)
where such books and records are normally kept and such examination shall be
conducted during the Audited Party’s normal business hours. The Audited Party
may require the accounting firm to sign a standard non-disclosure agreement with
terms that are not inconsistent with the terms of this Agreement before
providing the accounting firm access to the Audited Party’s facilities or
records. Upon completion of the audit, the accounting firm shall provide both
Celgene and Acceleron a written report disclosing whether the reports submitted
by the Audited Party are correct or incorrect and the specific details
concerning any discrepancies. No other information shall be provided to the
Auditing Party. If the accountant determines that, based on errors in the
reports so submitted, any report prepared in accordance with this Agreement is
incorrect, the Parties shall promptly revise the report and the associated
Royalty Report, PH Field Royalty Report or Reconciliation Statement and any
additional amount owed by one Party to the other shall be paid within [* * *]
days after receipt of the accountant’s report, along with interest as provided
in Section 5.8.5; provided, however, that no such interest shall be payable if
the errors leading to the Royalty Report, PH Field Royalty Report or
Reconciliation Statement being incorrect were in the reports provided by the
Party to receive such additional amount. Additionally, if the accountant
determines that the reports submitted by the Audited Party misstate the Audited
Party’s share of costs by more than [* * *] percent [* * *] to the Auditing
Party’s detriment, the Audited Party shall reimburse the Auditing Party for the
expenses incurred by the Auditing Party in conducting the audit. In the event of
any sublicense or transfer of rights with respect to Licensed Compounds or
Licensed Products by a Party under this Agreement, the sublicensor or transferor
shall provide for audit rights by the other Party to this Agreement in
accordance with this Section 5.8.4.
5.8.5.    Payments Between the Parties. There shall be a cash settlement between
the Parties no later than [* * *] days after the end of each Contract Quarter.
In the event that (a) any payment hereunder (including any royalty payment due
by Celgene to Acceleron under this Agreement) is made after the date specified
in the preceding sentence (other than the extent that a payment that is the
subject of a good faith dispute between the Parties that has been outstanding
for no more than [* * *] Business Days), and (b) such payment is overdue by more
than [* * *] Business Days, the paying Party shall pay interest to the other
Party at the lesser of (i) the annualized interest rate at the three (3) month
LIBOR plus one percent (1%) or (ii) the highest rate permitted by applicable law
from the date that such additional amount should have first been paid.

Article 6
EXCLUSIVITY

6.1    Prohibitions.

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6.1.1.    If Celgene irrevocably forfeits its rights to develop an Option
Compound pursuant to Article 7 (a “Forfeited Option Compound”), then, during the
Agreement Term, neither Acceleron nor any of its Affiliates, directly or
indirectly with a Third Party, shall, with any such Forfeited Option Compound or
product containing any such Forfeited Option Compound (i) conduct any clinical
study whose primary endpoint is [* * *] unless such clinical study is required
by any Regulatory Authority, in which event, the provisions of clauses (ii) and
(iii) of this Section shall apply notwithstanding the conduct of such clinical
trials, (ii) seek or obtain Regulatory Approval for such product indicated for
[* * *], or (iii) market or promote such product for the [* * *].
6.1.2.    During the Agreement Term, neither Acceleron nor any of its
Affiliates, directly or indirectly with a Third Party, shall, with any product
containing [* * *]: (i) conduct any clinical study whose primary endpoint is [*
* *] unless such clinical study is required by any Regulatory Authority, in
which event, the provisions of clauses (ii) and (iii) of this Section shall
apply notwithstanding the conduct of such clinical trials, (ii) seek or obtain
Regulatory Approval for such product indicated for [* * *], or (iii) market or
promote such product for [* * *]. Notwithstanding the foregoing, neither
Acceleron nor its Affiliates shall be restricted in any way, directly or
indirectly, from developing or commercializing [* * *] for [* * *].
6.1.3.    During the Agreement Term, neither Party nor any of its Affiliates,
directly or indirectly with a Third Party, shall, whether pursuant to this
Agreement or otherwise, with any product containing [* * *] (i) conduct any
clinical study whose primary endpoint is [* * *] unless such clinical study is
required by any Regulatory Authority, in which event, the provisions of clauses
(ii) and (iii) of this Section shall apply notwithstanding the conduct of such
clinical trials, (ii) seek or obtain Regulatory Approval for such product
indicated for [* * *], or (iii) market or promote such product for [* * *].
6.1.4.    In any Third Party license, development, research, collaboration,
commercialization or similar agreement with respect to an Option Compound, [* *
*], [* * *], or other product, as applicable, each Party and its Affiliates
shall include restrictions on such Third Party’s use of the Party’s or its
Affiliates intellectual property that are the same as those on the Parties and
its Affiliates set forth in this Section 6.1. For clarity, the prohibition on
conducting activities directly or indirectly with a Third Party includes a
prohibition on providing any support for an external or academic investigator or
site for conducting a clinical study.
6.1.5.    During the Agreement Term, neither Acceleron nor any of its
Affiliates, directly or indirectly with a Third Party, shall, with any product:
(a) conduct any clinical study whose primary endpoint is Use in Anemia unless
such clinical study is required by any Regulatory Authority, in which event, the
provisions of clauses (b) and (c) of this Section shall apply notwithstanding
the conduct of such clinical trials; (b) seek or obtain Regulatory Approval for
such product indicated for Use in Anemia; or (c) market or promote such product
for Use in Anemia. Notwithstanding the foregoing, the provisions of this Section
6.1.5 shall not apply to Acceleron or its Affiliates to the extent of conducting
the activities required to fulfill Acceleron’s obligations hereunder or under
the ACE-536 Agreement.

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6.1.6.    Subject to the terms of any definitive agreement entered into by the
Parties pursuant to Section 4.8, during the time period following the Amended
and Restated Effective Date and during the Agreement Term:
(a)    neither Celgene nor any of its Affiliates, directly or indirectly with a
Third Party, shall, with any Restricted Product: (i) conduct any clinical study
whose primary endpoint is an indication in the PH Field unless such clinical
study is required by any Regulatory Authority, in which event, the provisions of
clauses (ii) and (iii) of this Section 6.1.6(a) shall apply notwithstanding the
conduct of such clinical trials; (ii) seek or obtain Regulatory Approval for any
Restricted Product indicated for any indication in the PH Field; or (c) market
or promote any Restricted Product for any indication in the PH Field; provided
that, notwithstanding the foregoing, the provisions of this Section 6.1.6(a)
shall not apply to Celgene or its Affiliates to the extent of conducting the
activities required to fulfill Celgene’s obligations hereunder or under the
ACE-536 Agreement; and
(b)    neither Acceleron nor any of its Affiliates, directly or indirectly with
a Third Party, shall, with any Restricted Product: (i) conduct any clinical
study whose primary endpoint is an indication in the Celgene Field unless such
clinical study is required by any Regulatory Authority, in which event, the
provisions of clauses (ii) and (iii) of this Section 6.1.6(b) shall apply
notwithstanding the conduct of such clinical trials; (ii) seek or obtain
Regulatory Approval for any Restricted Product indicated for any indication in
the Celgene Field; or (iii) market or promote any Restricted Product for any
indication in the Celgene Field; provided that, notwithstanding the foregoing,
the provisions of this Section 6.1.6(b) shall not apply to Acceleron or its
Affiliates to the extent of conducting the activities required to fulfill
Acceleron’s obligations hereunder or under the ACE-536 Agreement.
6.1.7.    For purposes of this Article 6, each of the following terms shall have
the meanings set forth below:
(a)    “ACE-536 Licensed Product” means any Licensed Product (as defined in the
ACE-536 Agreement) that contains ACE-536 (as defined in the ACE-536 Agreement).
(b)    “Anemia” means anemias, disorders of red blood cells and disorders of
erythropoiesis. For the avoidance of doubt, “Anemia” includes any decrease in
function and quality of red blood cells, or any deficiency in the function of
red blood cells, or less than the normal quantity of hemoglobin in the blood, or
any deficiency in the function of hemoglobin.
(c)    “Use in Anemia” means the treatment, prevention, modulation or diagnosis
of Anemia, including any companion diagnostic or biomarkers associated with the
treatment, prevention, modulation or diagnosis of Anemia. For example, treatment
includes increase of hematocrit, hemoglobin, or red blood cells.
(d)    “Restricted Product” means any Licensed Compound, any Licensed Product,
ACE-536 (as defined in the ACE-536 Agreement) or any ACE-536 Licensed Product.

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6.2    Third Party Acquisitions.
6.2.1.    Bone-Loss, Anti-Cancer, Muscle Loss and PH Field Exclusivities. The
provisions of Sections 6.1.1, 6.1.2, 6.1.3 and 6.1.6 (and the provisions of
Section 6.1.4 related thereto) are not intended to apply to any activity
otherwise prohibited by such sections if a Party’s involvement in such
prohibited activity results from such Party’s acquisition by a Third Party
(either directly or through any Affiliate, whether by merger, purchase of assets
or equity, or otherwise), but only if (i) such Third Party, prior to such
acquisition or merger, was already engaged in such prohibited activity (the
“Third Party Activity”), and (ii) no Celgene Technology, Acceleron Technology,
or Joint Technology is used in connection with such Third Party Activities.
6.2.2.    Anemia Exclusivity. The provisions of Section 6.1.5 (and the
provisions of Section 6.1.4 related thereto) do not apply to any activity
otherwise prohibited by Section 6.1.5 if Acceleron’s involvement or the
involvement of any of its Affiliates in such prohibited activity results from or
occurs subsequently to the acquisition of Acceleron by a Third Party (either
directly or through any Affiliate, whether by merger, purchase of assets or
equity, or otherwise), but only if:
(a)    no Celgene Technology, Acceleron Technology or Joint Technology is used
in connection with such Third Party activities;
(b)     no Patent Rights Controlled by Acceleron or its Affiliates immediately
prior to the acquisition or Patent Rights developed based on the Know-How
described in Section 6.2.2(c) is used in connection with such Third Party
activities;
(c)    no Know-How relating to any TGF Beta superfamily compounds (including a
ligand, binding partner of a ligand, or a receptor of any such compounds)
Controlled by Acceleron or their Affiliates prior to the acquisition or further
Know-How relating to such TGF Beta superfamily compound developed based on such
existing Know-How is used in connection with such Third Party activities for the
longer of seven (7) years from the Effective Date or five (5) years from the
date of the acquisition of Acceleron by a Third Party; and
(d)    no Know-How Controlled by Celgene or its Affiliates that is provided,
prior to the acquisition, to Acceleron pursuant to this Agreement or developed
based on such existing Know-How is used in connection with such Third Party
activities.
6.2.3.    Acquisitions of Acceleron by Certain Third Parties. Subsequent to an
acquisition of Acceleron by a designated Third Party set forth in Schedule
6.2.3, the following shall apply:
(a)    Notwithstanding anything to the contrary in Section 2.1.1, Celgene shall
be solely responsible for conducting all Development activities of each

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Licensed Compound or related Licensed Product in the Celgene Field except for PH
Field Development Activities which shall still be conducted by or on behalf of
Acceleron pursuant to Section 2.1.1 and this Section 6.2.3;
(b)    Notwithstanding anything to the contrary in Section 2.4.1, Celgene may,
within ninety (90) days, provide Acceleron with written notice, at Celgene’s
sole discretion, instructing Acceleron to cease all Manufacturing activities
hereunder; and
(c)    Celgene’s obligation to provide reports under Article 2 and Article 3
shall cease; provided, however, that Celgene shall continue to provide reports
under Section 2.9.3 (which reports will be respect to the entire Territory, not
just outside North America and Europe) and semiannual reports regarding
Development of Licensed Products.

6.3    Acquisitions of Third Parties. The provisions of this Article 6 do not
apply to any activity otherwise prohibited by this Article 6 if a Party’s
involvement or the involvement of any of its Affiliates in such prohibited
activity results from such Party’s acquisition (either directly or through any
Affiliate, whether by merger, purchase of assets or equity, or otherwise) of all
or substantially all of the business or assets of a Third Party, but only if (i)
such Third Party, prior to such acquisition or merger, was already engaged in
such prohibited activity (the “Acquired Party Activity”), and (ii) such
acquiring Party shall, within thirty (30) days after the date of such Party’s
consummation of such acquisition, notify the other Party of such acquisition and
comply with the other provisions of this Section 6.3. Following consummation of
such an acquisition, the acquiring Party shall, at its option, either (i) use
good faith efforts to identify a Third Party purchaser to whom such Party will
divest its interest in the Acquired Party Activity and to enter into a
definitive agreement with such Third Party for such divestiture as soon as
reasonably practicable under the circumstances, but such divestiture must be
completed no later than twelve (12) months after the closing of such Party’s
acquisition of the Acquired Party Activity, or (ii) promptly discontinue such
Acquired Party Activity; provided that, notwithstanding which option is chosen,
such divesture or discontinuation must be accomplished no later than twelve (12)
months after the closing of such Party’s acquisition of the Acquired Party
Activity. During the time period following the consummation of an acquisition
covered by this Section 6.3 through the divestiture or discontinuation of the
Acquired Party Activity, the acquiring Party shall not use any Celgene
Technology, Acceleron Technology, or Joint Technology in connection with such
Acquired Party Activities. So long as the acquiring Party divests of, or
discontinues, the Acquired Party Activity in accordance with this Section 6.3,
such acquisition shall not be deemed a violation of this Article 6.
Notwithstanding anything to the contrary in this Article 6, this Section 6.3
shall not apply to any activity of Acceleron, its Affiliates or a Third Party
acquirer of Acceleron subsequent to the acquisition of Acceleron by a Third
Party (either directly or through any Affiliate, whether by merger, purchase of
assets or equity, or otherwise); provided that the provisions of Section 6.2
shall continue to apply to Acceleron, its Affiliates, a Third Party acquirer of
Acceleron and any Third Party acquired by Acceleron (either directly or through
any Affiliate, whether by merger, purchase of assets or equity, or otherwise).

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6.4    Termination of ACE-536 Agreement. In the event of termination of the
ACE-536 Agreement by Acceleron for cause under Section 10.2.1 of the ACE-536
Agreement, Acceleron’s use of any “Licensed Compounds” or “Licensed Products”
under the ACE-536 Agreement shall no longer be subject to the exclusivity
provisions of Article 6 of this Agreement that relate to a product for Use in
Anemia; provided that, for the avoidance of doubt, any other exclusivity
provisions of this Agreement shall continue to apply. For the avoidance of
doubt, termination of the ACE-536 Agreement under Section 10.3 or Section 10.4
of the ACE-536 Agreement or expiration of the ACE-536 Agreement shall not affect
any rights or obligations of the Parties under this Agreement, and Acceleron’s
use of any “Licensed Compounds” or “Licensed Products” under the ACE-536
Agreement shall continue to be subject to any exclusivity provisions of this
Agreement.

Article 7
OPTION PROGRAM

7.1    Conduct of Option Compound Programs. Acceleron shall be solely
responsible for, and shall pay all costs associated with, managing all
Development, and Manufacturing activities for each Option Compound through the
completion of Phase 2A Clinical Trials for each Option Compound in its sole
discretion. Unless Celgene forfeits its right to an Option Compound pursuant to
Section 7.2, for a period of [* * *] from the Effective Date, Celgene shall have
the exclusive option to such Option Compound in accordance with the terms
hereof, and Acceleron shall not grant any Third Party any rights to such Option
Compound.

7.2    Option Program Payments. With respect to products containing [* * *]
Antibodies, [* * *] Antibodies, or [* * *] Antibodies, Acceleron shall provide
Celgene with written notice after the earliest date on which the corresponding
milestone event has first been achieved with respect to the applicable Option
Compound. In the event that Celgene makes each payment set forth in the chart
below, through and including the payment due upon completion of a Phase 2A
Clinical Trial, (the “Option Program Payments”) with respect to products
containing [* * *] Antibodies, [* * *] Antibodies, or [* * *] Antibodies no
later than [* * *] days (or [* * *] days in the case of the third milestone
event related to delivery of the results of the Phase 2A Clinical Trial) after
Celgene’s receipt of notice from Acceleron that the corresponding milestone
event has first been achieved with respect to the applicable Option Compound,
(i) the definition of “Licensed Compound” shall automatically be deemed,
effective as of the date of receipt of the last applicable Option Program
Payment by Acceleron, to include [* * *] Antibodies, [* * *] Antibodies, or [* *
*] Antibodies, as applicable, and (ii) the definition of “Acceleron Patent
Rights” shall automatically be deemed, effective as of the date of receipt of
the last applicable Option Program Payment by Acceleron, to include the [* * *]
Antibody Patent Rights, [* * *] Antibody Patent Rights, or [* * *] Antibody
Patent Rights, as applicable. In the event that Celgene does not make each
Option Program Payment for a particular Option Compound within the required time
period, Celgene shall fully and irrevocably forfeit any right to develop such
Option Compound, and all right, title and interest in such Option Compound shall
remain the property of Acceleron. For clarity, the making of any Option Program
Payment is solely within the discretion of Celgene.

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Milestone Event
Payment for Each Option Compound
 
[* * *]
[* * *]
[* * *]
[* * *]
$[* * *]
$[* * *]
$[* * *]
[* * *]
$[* * *]
$[* * *]
$[* * *]
[* * *]
$[* * *]
$[* * *]
$[* * *]

For clarity, each Option Program Payment set forth in this Section 7.2 shall be
paid only once for each Option Compound, regardless of whether more than one
Clinical Trial may be conducted for such Option Compound.

7.3    Updates; Reports. For so long as Celgene’s option under this Article 7
remains in place, Acceleron shall provide Celgene with regular updates no less
than once a [* * *] on the results of the Option Compound Development program.
Such updates shall be conducted by telephone or video-conference, and prior to
each such update, Acceleron shall provide Celgene with a written summary of the
activities conducted under the Option Compound program for the preceding [* * *]
and supporting data related thereto. Celgene shall have the right to reasonably
request and to receive in a timely manner clarifications and answers to
questions with respect to such reports.

Article 8
INTELLECTUAL PROPERTY PROTECTION AND RELATED MATTERS

8.1    Salk Patent Rights.
8.1.1.    Celgene acknowledges that the Acceleron Patent Rights listed on
Schedule 8.1 (the “Salk Patent Rights”) have been licensed by Acceleron from
Salk pursuant to the Salk License.
8.1.2.    Acceleron acknowledges that, pursuant to the Salk License, it has the
below rights with respect to the Salk Patent Rights and agrees to keep Celgene
fully informed of these rights, as well as provide to Celgene all information
and copies of documents received from Salk or its patent counsel relating to the
Salk Patent Rights:
(a)    The right to proceed with the Prosecution of the Salk Patent Rights in
the event that Salk does not exercise its rights to do so;
(b)    The right, in certain circumstances, to review any patent documents prior
to filing and to provide comments and suggestions for revision thereof; and
(c)    The right, in certain circumstances, to initiate legal proceedings
against third parties for infringement of the Salk Patent Rights.

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8.1.3.    In the event that Acceleron is permitted to proceed with Prosecution,
provide comments or suggestions to patent documents, or initiate legal
proceedings with respect to the Salk Patent Rights, then such Salk Patent Rights
shall be treated in the same manner as other Acceleron Patent Rights under this
Article 8, and Acceleron shall exercise all such rights with respect to the Salk
Patent Rights pursuant to the instructions of Celgene, if Celgene is given the
first right to act under this Article 8.

8.2    Prosecution of Patent Rights.
8.2.1.    Other Acceleron Patent Rights and Joint Patent Rights. The following
terms shall apply to all Acceleron Patent Rights owned by Acceleron and all
Joint Patent Rights.
(a)    Primary Responsibility.
(i)    Acceleron, through counsel of its choosing, shall have primary
responsibility for and control over obtaining, filing, prosecuting (including
any interferences, reissue proceedings, re-examinations, oppositions, and
revocations), and maintaining (collectively, “Prosecuting” or, when used as a
noun, “Prosecution”) throughout the Territory the Acceleron Patent Rights (and,
for clarity, will be the “Prosecuting Party” with respect to the Acceleron
Patent Rights), and Celgene shall cooperate with Acceleron in regard thereto.
Celgene, through counsel of its choosing, shall have primary responsibility for
and control over Prosecuting throughout the Territory the Joint Patent Rights
(and, for clarity, will be the “Prosecuting Party” with respect to the Joint
Patent Rights), and Acceleron shall cooperate with Celgene in regard thereto. If
the Prosecuting Party elects to abandon (except in the course of Prosecution to
pursue such subject matter or claim in a continuing application) any subject
matter or claim that (x) relates to any of the rights licensed to the
Non-Prosecuting Party hereunder or (y) is filed or requested to be filed by a
Prosecuting Party at the request of the Non-Prosecuting pursuant to Section
8.2.1(a)(ii), the Prosecuting Party shall so notify the Non-Prosecuting Party
promptly (but no less than [* * *] prior to any deadlines for Prosecution) in
writing of its intention in good time to enable the Non-Prosecuting Party to
meet any deadlines by which an action must be taken to preserve any such rights
in such subject matter or claim, and the Non-Prosecuting Party shall be entitled
to acquire control of Prosecuting such subject matter or claim and be deemed the
Prosecuting Party with respect thereto.
(ii)    Notwithstanding the foregoing, the Prosecuting Party’s choice of outside
patent counsel shall be reasonably acceptable to the Non-Prosecuting Party, and
the Prosecuting Party shall keep the Non-Prosecuting Party fully informed of
Prosecution and provide the Non-Prosecuting Party with copies of material
correspondence (including applications, office actions, responses, etc.)
relating to Prosecution of any Patent Rights being Prosecuted by such
Prosecuting Party. The Non-Prosecuting Party may provide comments and

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suggestions with respect to any material actions to be taken by the Prosecuting
Party, and the Prosecuting Party shall reasonably consider all comments and
suggestions and shall take all Prosecution actions reasonably recommended by the
Non-Prosecuting Party. The Prosecuting Party shall consult with the
Non-Prosecuting Party before taking any action that would have a material
adverse impact on the scope of claims within the Acceleron Patent Rights or
Joint Patent Rights, as applicable. The Prosecuting Party shall use Commercially
Reasonable Efforts to Prosecute additional claims substantially similar to those
suggested by the Non-Prosecuting Party, if any, in such jurisdictions of the
Territory requested by the Non-Prosecuting Party.
(iii)    In order to facilitate the Non-Prosecuting Party’s right to comment,
the Prosecuting Party shall provide copies of all such official correspondence
and any proposed responses by the Prosecuting Party at least [* * *] days prior
to any filing or response deadlines, or within [* * *] Business Days of the
Prosecuting Party’s receipt of any official correspondence if such
correspondence only allows for [* * *] or less to respond, and the
Non-Prosecuting Party shall provide any comments promptly and in sufficient time
to allow the Prosecuting Party to meet applicable filing requirements. In no
event shall the Prosecuting Party be required to delay any submission, filing or
response past any deadline that is not extendable. The Prosecuting Party agrees
to use Commercially Reasonable Efforts to avoid extension fees, unless agreed to
in advance by the Parties, and to take such action as deemed reasonably
necessary to preserve pendency of the Patent Rights being Prosecuted by such
Prosecuting Party, including the filing of any new or continuing patent
application or payment of any fee necessary to preserve pendency of a pending
application.
(iv)    Acceleron covenants and agrees that it shall not grant any Third Party
any right to control the Prosecution of the Acceleron Patent Rights or to
approve or consult with respect to any Patent Rights licensed to Celgene
hereunder, in any case, that is more favorable to the rights granted to Celgene
hereunder or otherwise conflicts with Celgene’s rights hereunder.
(b)    Common Interest. All information exchanged between the Parties or between
the Parties’ outside patent counsel regarding Prosecution of the Acceleron
Patent Rights or Joint Patent Rights shall be deemed Confidential Information.
In addition, the Parties acknowledge and agree that, with regard to such
Prosecution of the Acceleron Patent Rights or Joint Patent Rights, the interests
of the Parties as licensor and licensee are to obtain the strongest patent
protection possible, and as such, are aligned and are legal in nature. The
Parties agree and acknowledge that they have not waived, and nothing in this
Agreement constitutes a waiver of, any legal privilege concerning the Acceleron
Patent Rights or Joint Patent Rights, including privilege under the common
interest doctrine and similar or related doctrines.

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(c)    Election Not to Continue Prosecution; Abandonment. If a Prosecuting Party
elects (i) not to Prosecute patent applications for the Acceleron Patent Rights
or Joint Patent Rights under its Prosecution control in any country, (ii) not to
continue the Prosecution of any Acceleron Patent Right or Joint Patent Right
under its Prosecution control in a particular country in the Territory, (iii)
not to Prosecute patent applications for the Acceleron Patent Rights or Joint
Patent Rights under its Prosecution control in a particular country following a
written request from the Non-Prosecuting Party to Prosecute in such country, or
(iv) not to Prosecute patent applications for the Acceleron Patent Rights or
Joint Patent Rights under its Prosecution control reasonably sufficient to
protect the Licensed Compounds and Licensed Product following a written notice
from the Non-Prosecuting Party setting forth the Non-Prosecuting Party’s good
faith analysis of the insufficiency of the Prosecuting Party’s patent
applications, then the Prosecuting Party shall so notify the Non-Prosecuting
Party promptly (but no less than 30 days prior to the date that a response is
due) in writing of its intention in good time to enable the Non-Prosecuting
Party to meet any deadlines by which an action must be taken to establish or
preserve any such rights in such patent in such country, and the Prosecuting
Party shall permit the Non-Prosecuting Party, should the Non-Prosecuting Party
choose to do so, to Prosecute or otherwise pursue such Acceleron Patent Rights
or Joint Patent Rights in such country in the Non-Prosecuting Party’s own name,
and the Prosecuting Party shall cooperate with the Non-Prosecuting Party in
regard thereto.
8.2.2.    Celgene Patent Rights.
(a)    Prosecution outside the PH Field. Celgene, through counsel of its
choosing, shall have the sole responsibility for and control over Prosecuting
throughout the Territory the Celgene Patent Rights, but shall have no obligation
to Prosecute such Patent Rights.
(b)    Prosecution in the PH Field.
(i)    Celgene, through counsel of its choosing, shall have primary
responsibility for and control over Prosecuting throughout the Territory the PH
Field Celgene Patent Rights (and, for clarity, will be the “Prosecuting Party”
with respect to such PH Field Celgene Patent Rights), and Acceleron shall
cooperate with Celgene in regard thereto. If Celgene elects to abandon (except
in the course of Prosecution to pursue such subject matter or claim in a
continuing application) any subject matter or claim that (x) relates to any of
the rights licensed to Acceleron hereunder or (y) is filed or requested to be
filed by Celgene at the request of Acceleron pursuant to Section 8.2.2(b)(ii),
Celgene shall so notify Acceleron promptly (but no less than [* * *] prior to
any deadlines for Prosecution) in writing of its intention in good time to
enable Acceleron to meet any deadlines by which an action must be taken to
preserve any such rights in such subject matter or claim, and notwithstanding
Section 8.2.2(a), Acceleron shall be entitled to acquire control of Prosecuting

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such subject matter or claim and be deemed the Prosecuting Party with respect
thereto.
(ii)    Notwithstanding the foregoing, the Prosecuting Party’s choice of outside
patent counsel shall be reasonably acceptable to the Non-Prosecuting Party, and
the Prosecuting Party shall keep the Non-Prosecuting Party fully informed of
Prosecution and provide the Non-Prosecuting Party with copies of material
correspondence (including applications, office actions, responses, etc.)
relating to Prosecution of any Patent Rights being Prosecuted by such
Prosecuting Party. The Non-Prosecuting Party may provide comments and
suggestions with respect to any material actions to be taken by the Prosecuting
Party, and the Prosecuting Party shall reasonably consider all comments and
suggestions and shall take all Prosecution actions reasonably recommended by the
Non-Prosecuting Party. The Prosecuting Party shall consult with the
Non-Prosecuting Party before taking any action that would have a material
adverse impact on the scope of claims within any PH Field Celgene Patent Right.
The Prosecuting Party shall use Commercially Reasonable Efforts to Prosecute
additional claims substantially similar to those suggested by the
Non-Prosecuting Party, if any, in such jurisdictions of the Territory requested
by the Non-Prosecuting Party.
(iii)    In order to facilitate the Non-Prosecuting Party’s right to comment,
the Prosecuting Party shall provide copies of all such official correspondence
and any proposed responses by the Prosecuting Party at least [* * *] prior to
any filing or response deadlines, or within [* * *] of the Prosecuting Party’s
receipt of any official correspondence if such correspondence only allows for [*
* *] or less to respond, and the Non-Prosecuting Party shall provide any
comments promptly and in sufficient time to allow the Prosecuting Party to meet
applicable filing requirements. In no event shall the Prosecuting Party be
required to delay any submission, filing or response past any deadline that is
not extendable. The Prosecuting Party agrees to use Commercially Reasonable
Efforts to avoid extension fees, unless agreed to in advance by the Parties, and
to take such action as deemed reasonably necessary to preserve pendency of such
PH Field Celgene Patent Rights being Prosecuted by such Prosecuting Party,
including the filing of any new or continuing patent application or payment of
any fee necessary to preserve pendency of a pending application.
(iv)    Celgene covenants and agrees that it shall not grant any Third Party any
right to control the Prosecution of any of the PH Field Celgene Patent Rights or
to approve or consult with respect to any such PH Field Celgene Patent Rights,
in any case, that is more favorable to the rights granted to Acceleron hereunder
or otherwise conflicts with Acceleron’s rights hereunder.

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(v)    All information exchanged between the Parties or between the Parties’
outside patent counsel regarding Prosecution of the PH Field Celgene Patent
Rights shall be deemed Confidential Information. In addition, the Parties
acknowledge and agree that, with regard to such Prosecution of such PH Field
Celgene Patent Rights, the interests of the Parties as licensor and licensee are
to obtain the strongest patent protection possible, and as such, are aligned and
are legal in nature. The Parties agree and acknowledge that they have not
waived, and nothing in this Agreement constitutes a waiver of, any legal
privilege concerning the PH Field Celgene Patent Rights, including privilege
under the common interest doctrine and similar or related doctrines.
(vi)     If a Prosecuting Party elects, (i) not to Prosecute patent applications
for any PH Field Celgene Patent Right under its Prosecution control in any
country, (ii) not to continue the Prosecution of any PH Field Celgene Patent
Right under its Prosecution control in a particular country in the Territory,
(iii) not to Prosecute patent applications for any PH Field Celgene Patent Right
under its Prosecution control in a particular country following a written
request from the Non-Prosecuting Party to Prosecute in such country, or (iv) not
to Prosecute patent applications for any PH Field Celgene Patent Right under its
Prosecution control reasonably sufficient to protect Sotatercept Licensed
Compounds and the Sotatercept Licensed Products following a written notice from
the Non-Prosecuting Party setting forth the Non-Prosecuting Party’s good faith
analysis of the insufficiency of the Prosecuting Party’s patent applications,
then the Prosecuting Party shall so notify the Non-Prosecuting Party promptly
(but no less than [* * *] prior to the date that a response is due) in writing
of its intention in good time to enable the Non-Prosecuting Party to meet any
deadlines by which an action must be taken to establish or preserve any such
rights in such patent in such country, and the Prosecuting Party shall permit
the Non-Prosecuting Party, should the Non-Prosecuting Party choose to do so, to
Prosecute or otherwise pursue such PH Field Celgene Patent Right in such country
in the Non-Prosecuting Party’s own name, and the Prosecuting Party shall
cooperate with the Non-Prosecuting Party in regard thereto.
8.2.3.    Cooperation. Each Party hereby agrees: (a) to make its employees,
agents and consultants reasonably available to the other Party (or to the other
Party’s authorized attorneys, agents or representatives), to the extent
reasonably necessary to enable such Party to undertake patent Prosecution as
contemplated by this Agreement; (b) to cooperate, if necessary and appropriate,
with the other Party in gaining patent term extensions wherever applicable to
Patent Rights that are subject to this Agreement; and (c) to endeavor in good
faith to coordinate its efforts with the other Party to minimize or avoid
interference with the Prosecution of the other Party’s patent applications that
are subject to this Agreement.
8.2.4.    Patent Procurement Costs.

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(a)    All Patent Procurement Costs related to Prosecuting Patent Rights
hereunder in Designated Countries shall be shared by the Parties as follows: (i)
Patent Procurement Costs relating to the Prosecution of Celgene Patent Rights in
Designated Countries or any other countries in the Territory shall be paid for
by Celgene, (ii) Patent Procurement Costs relating to the Prosecution of Joint
Patent Rights in Designated Countries shall be borne equally by the Parties and
(iii) Patent Procurement Costs relating to the Prosecution of Acceleron Patent
Rights in Designated Countries shall be borne [* * *] percent [* * *] by
Acceleron and [* * *] percent [* * *] by Celgene.
(b)    In the event that Celgene requests that an Acceleron Patent Right or a
Joint Patent Right be Prosecuted in any country other than the Designated
Countries, then any Patent Procurement Costs relating to such Prosecution of
such Acceleron Patent Right or Joint Patent Right, as applicable, in such
country shall be deemed a Development Cost. In the event that Acceleron requests
that a Joint Patent Right or PH Field Celgene Patent Right be Prosecuted in any
country other than the Designated Countries, then any Patent Procurement Costs
relating to such Prosecution of such Joint Patent Right in such country shall be
borne [* * *] percent [* * *] by Acceleron and [* * *] percent [* * *] by
Celgene.
(c)    Notwithstanding anything else in this Section 8.2.4, any Patent
Procurement Costs owed by Acceleron to Salk or any other third party licensor
pursuant to an agreement executed by Acceleron prior to the Effective Date (or,
with respect to any Option Compound, prior to the date that such Option Compound
is deemed a Licensed Compound in accordance with Article 7) shall be borne
solely by Acceleron.

8.3    Enforcement of Patent Rights.
8.3.1.    Notification. Each Party shall promptly report in writing to the other
Party during the Agreement Term any (a) known or suspected infringement of any
Acceleron Patent Rights, Joint Patent Rights or Celgene Patent Rights claiming
or relating to Licensed Compounds or Licensed Products, by a Third Party or (b)
unauthorized use or misappropriation of any Confidential Information, including
Acceleron Technology, Joint Technology and Celgene Technology claiming or
relating to Licensed Compounds or Licensed Products, by a Third Party of which
it becomes aware and shall provide the other Party with all available evidence
supporting such infringement, or unauthorized use or misappropriation.
8.3.2.    Rights to Enforce.
(a)    Acceleron Technology. The following terms shall apply to all Acceleron
Patent Rights, Acceleron Improvements and Acceleron Know-How owned by Acceleron
and, with respect to other Acceleron Technology (excluding Acceleron
Collaboration IP), including Salk Patent Rights, to the extent permitted by the
Salk Licenses or other applicable third party licenses. In respect of Licensed
Compounds

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and Licensed Products in the Territory, Acceleron shall have the first right,
but not the obligation, to take any reasonable measures it deems appropriate to
stop infringing activities in the Field in the Territory with respect to
(including initiating or prosecuting an infringement or other appropriate suit
or action against any Third Party who at any time has infringed, or is suspected
of infringing, or defending any declaratory judgment action with respect to) any
Acceleron Patent Rights claiming or relating to Licensed Compounds or Licensed
Products or of using without proper authorization any Acceleron Know-How and
Acceleron Improvements. In the event that Acceleron elects not to take action
pursuant to this Section 8.3.2(a), Acceleron shall so notify Celgene promptly in
writing of its intention in good time to enable Celgene to meet any deadlines by
which an action must be taken to establish or preserve any enforcement rights,
and Celgene shall have the right (to the extent Acceleron has the ability to
grant Celgene such right with respect to the Salk Patent Rights or other
applicable Third Party Patent Rights), but not the obligation, to take any such
reasonable measures to stop such infringing activities by such alleged
infringer.
(b)    Acceleron Collaboration IP; Joint Technology. The following terms shall
apply to all Joint Technology and all Acceleron Collaboration IP. In respect of
Licensed Compounds and Licensed Products in the Territory, Celgene shall have
the first right, but not the obligation, to take any reasonable measures it
deems appropriate to stop infringing activities in the Field in the Territory
with respect to (including initiating or prosecuting an infringement or other
appropriate suit or action against any Third Party who at any time has
infringed, or is suspected of infringing, or defending any declaratory judgment
action with respect to) any Joint Patent Rights claiming or relating to Licensed
Compounds or Licensed Products or of using without proper authorization any
Joint Improvements, Joint Collaboration IP or Acceleron Collaboration IP. In the
event that Celgene elects not to take action pursuant to this Section 8.3.2(b),
Celgene shall so notify Acceleron promptly in writing of its intention in good
time to enable Acceleron to meet any deadlines by which an action must be taken
to establish or preserve any enforcement rights, and Acceleron shall have the
right, but not the obligation, to take any such reasonable measures to stop such
infringing activities by such alleged infringer. In any enforcement action
involving Joint Technology, the Parties agree to be joined as parties to such
enforcement action if necessary to enable the enforcement action.
(c)    Celgene Technology. The following terms shall apply to all Celgene Patent
Rights, Celgene Improvements, Celgene Collaboration IP and Celgene Know-How
owned by Celgene and, with respect to other Celgene Technology, to the extent
permitted by the applicable licenses. Celgene shall have the sole right, but not
the obligation, to take any reasonable measures it deems appropriate to stop
infringing activities in the Field in the Territory, including initiating or
prosecuting an infringement or other appropriate suit or action against any
Third Party who at any time has infringed, or is suspected of infringing, or
defending any declaratory judgment action with respect to, any Celgene Patent
Rights claiming or relating to

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Licensed Compounds or Licensed Products or of using without proper authorization
any Celgene Know-How, Celgene Improvements or Celgene Collaboration IP.
8.3.3.    Procedures; Expenses and Recoveries. The Party having the right to
initiate any infringement suit under Section 8.3.2(a) or 8.3.2(b) above shall
have the sole and exclusive right to select counsel for any such suit (which
counsel shall be reasonably acceptable to the other Party) and shall pay all
expenses of the suit, including attorneys’ fees and court costs and
reimbursement of the other Party’s reasonable out-of-pocket expense in rendering
assistance requested by the initiating Party. If required under Applicable Law
in order for the initiating Party to initiate or maintain such suit, or if
either Party is unable to initiate or prosecute such suit solely in its own name
or it is otherwise advisable to obtain an effective legal remedy, in each case,
the other Party shall join as a party to the suit and shall execute and cause
its Affiliates to execute all documents necessary for the initiating Party to
initiate litigation to prosecute and maintain such action. The initiating Party
will keep the other Party reasonably informed of the status of the infringement
suit. At the initiating Party’s request, the other Party shall provide
reasonable assistance to the initiating Party in connection with an infringement
suit at no charge to the initiating Party except for reimbursement by the
initiating Party of reasonable out-of-pocket expenses incurred in rendering such
assistance. The non-initiating Party may participate and be represented in any
such suit by its own counsel at its own expense. If the Parties obtain from a
Third Party, in connection with such suit under Section 8.3.2(a) or 8.3.2(b),
any damages, license fees, royalties or other compensation (including any amount
received in settlement of such litigation), such amounts shall be allocated as
follows:
(a)    to reimburse each Party for all expenses of the suit, including
attorneys’ fees and disbursements, court costs and other litigation expenses;
and
(b)    any remaining amount shall be [* * *] unless the infringement relates
solely to Sotatercept Licensed Compounds and Sotatercept Licensed Products in
the PH Field, in which case any remaining amount shall be [* * *].

8.4    Claimed Infringement of Third Party Rights.
8.4.1.    Notice. In the event that a Third Party at any time provides written
notice of a claim to, or brings an action, suit or proceeding against, any
Party, or any of their respective Affiliates or Sublicensees, claiming
infringement of such Third Party’s patent rights or unauthorized use or
misappropriation of its know-how based upon an assertion or claim arising out of
the Development, Manufacture or Commercialization of a Licensed Compound or
Licensed Product in the Territory (“Infringement Claim”), such Party shall
promptly notify the other Party of the Infringement Claim or the commencement of
such action, suit or proceeding, enclosing a copy of the Infringement Claim and
all papers served. Each Party agrees to make available to the other Party its
advice and counsel regarding the technical merits of any such claim at no cost
to the other Party and to offer reasonable assistance to the other Party at no
cost to the other Party.

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8.4.2.    Right to Defend. Celgene shall have the right, but not the obligation,
to defend any Infringement Claim brought against Celgene or its Affiliates or
Sublicensees arising out of the Development, Manufacture or Commercialization of
a Licensed Compound or Licensed Product in the Territory. With respect to any
such Infringement Claim brought against Acceleron or its Affiliates, Acceleron
shall notify Celgene, and the Parties, in good faith, shall determine who should
defend such suit; provided that, for any Infringement Claim brought against
Acceleron or its Affiliates or Sublicensees arising solely out of the
Development or Commercialization of an Sotatercept Licensed Compound or
Sotatercept Licensed Product in the PH Field in the Territory, Acceleron shall
have the right, but not the obligation, to defend such Infringement Claim. All
litigation costs and expenses incurred by the Defending Party (as defined below)
in connection with such Infringement Claim, and all damages, payments and other
amounts awarded against, or payable by, either Party under any settlement with
such Third Party shall be borne by the Defending Party.
8.4.3.    Procedure. The Party having the obligation or first right to defend an
Infringement Claim shall be referred to as the “Defending Party.” The Defending
Party shall have the sole and exclusive right to select counsel for any
Infringement Claim; provided that such counsel shall be reasonably acceptable to
the other Party. The Defending Party shall keep the other Party fully informed
of any such claims, shall consult with the other Party with respect to the
strategy and conduct of any defense of such claims, and shall provide the other
Party with copies of all documents filed in, and all written communications
relating to, any suit brought in connection with such claims, which copies of
documents filed or communications sent by the Defending Party will be provided
in advance of filing or sending. The other Party may provide comments and
suggestions with respect to any material actions to be taken by the Defending
Party, and the Defending Party shall reasonably consider all comments and
suggestions and shall take all prosecution actions reasonably recommended by the
other Party. The other Party may also participate and be represented in any such
claim or related suit, at its own expense. The other Party shall have the sole
and exclusive right to control the defense of an Infringement Claim in the event
the Defending Party fails to exercise its right to assume such defense within
thirty (30) days following written notice from the other Party of such
Infringement Claim. No Party shall settle any claims or suits involving rights
of another Party (or rights of such Party to the extent they are licensed to
such other Party) without obtaining the prior written consent of such other
Party, which consent shall not be unreasonably withheld.
8.4.4.    Limitations. EXCEPT AS OTHERWISE EXPRESSLY PROVIDED IN SECTION 11.7,
THE FOREGOING STATES THE ENTIRE RESPONSIBILITY OF ACCELERON AND CELGENE, AND THE
SOLE AND EXCLUSIVE REMEDY OF ACCELERON OR CELGENE, AS THE CASE MAY BE, IN THE
CASE OF ANY CLAIMED INFRINGEMENT OF ANY THIRD PARTY PATENT RIGHTS OR
UNAUTHORIZED USE OR MISAPPROPRIATION OF ANY THIRD PARTY’S KNOW-HOW.

8.5    Other Infringement Resolutions. In the event of a dispute or potential
dispute that has not ripened into a demand, claim or suit of the types described
in Sections 8.3 and 8.4 of this Agreement (e.g., actions seeking declaratory
judgments and revocation proceedings), the same

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principles governing control of the resolution of the dispute, consent to
settlements of the dispute, and implementation of the settlement of the dispute
shall apply.

8.6    Product Trademarks & Product Designation.
8.6.1.    Subject to Section 8.6.2, (a) Celgene shall select and own the Product
Trademarks for each Licensed Product and shall be solely responsible for filing
and maintaining the Product Trademarks in the Territory and (b) Celgene shall
assume full responsibility, at its sole cost and expense, for any infringement
of a Product Trademark for a Licensed Product by a Third Party (and shall retain
in full any recoveries for such infringement) and shall defend and indemnify
Acceleron for and against any claims of infringement of the rights of a Third
Party by Acceleron’s use of a Product Trademark in connection with a Licensed
Product in accordance with the terms of this Agreement. In addition, Celgene
shall have the right to select the product designation or generic name for the
Licensed Compounds and Licensed Products; provided that Acceleron’s consent to
such designation or name shall be required for an Sotatercept Licensed Compound
or Sotatercept Licensed Product being Developed or Commercialized by or on
behalf of Acceleron, its Affiliate or Sublicensee in the PH Field.
8.6.2.    Acceleron shall select and own the Product Trademarks for each
Sotatercept Licensed Product being or to be Commercialized solely in the PH
Field and shall be solely responsible for filing and maintaining such Product
Trademarks in the Territory. Acceleron shall assume full responsibility, at its
sole cost and expense, for any infringement of such a Product Trademark by a
Third Party (and shall retain in full any recoveries for such infringement).

8.7    Marking. Each Party agrees to mark, and to require any Affiliate or
Sublicensee, to mark any Licensed Product (or their containers or labels) made,
sold, or otherwise distributed by it or them with any notice of patent rights
necessary or desirable under Applicable Law to enable the Acceleron Patent
Rights to be enforced to their full extent in any country where Licensed
Products are made, used, sold, or offered for sale. In all countries within
North America, to the extent legally permissible, both Parties’ names and logos
will appear with equal prominence on Licensed Product labels and promotional
materials. In any such country within North America where this is not legally
permitted, the Parties agree to work together in good faith to identify a
mechanism to allow the association of both Parties’ names with the Product.

8.8    Patent Term Extensions. The Parties shall use reasonable efforts to
obtain all available supplementary protection certificates (“SPC”) and other
extensions of the Celgene Patent Rights, Acceleron Patent Rights and Joint
Patent Rights (including those available under the Hatch-Waxman Act). Each Party
shall execute such authorizations and other documents and take such other
actions as may be reasonably requested by the other Party to obtain such
extensions. The Parties shall cooperate with each other in gaining patent term
restorations, extensions or SPCs wherever applicable to Celgene Patent Rights,
Acceleron Patent Rights or Joint Patent Rights. The Party first eligible to seek
patent term restoration or extension of any such Patent Rights or any SPC
related thereto may do so; provided, that if in any country the first Party has
an option to extend the patent

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term for only one of several patents, the first Party shall consult with the
other Party before making the election; provided, further that, notwithstanding
the foregoing, if, at the time the first Party becomes eligible to seek patent
term restoration or extension of any such Patent Rights or any SPC related
thereto, the other Party is Developing or Commercializing a Licensed Product in
their respective Subfield, then the decisions to seek any such patent term
restoration or extension of any such Patent Rights or any SPC related thereto
and, if applicable, elect one of several patents for which to extend the patent
term shall require the mutual consent of both Parties. If more than one patent
is eligible for extension or patent term restoration, the Parties shall select
in good faith a strategy that shall maximize patent protection and commercial
value for each Licensed Product. All filings for such extensions and
certificates shall be made by the Party to whom responsibility for Prosecution
of the Celgene Patent Rights, Acceleron Patent Rights or Joint Patent Rights are
assigned; provided that, in the event that the Party to whom such responsibility
is assigned elects not to file for an extension or SPC, such Party shall (a)
inform the other Party of its intention not to file, (b) grant the other Party
the right to file for such extension or SPC in the Patent Rights’ owner’s name,
and (c) provide all necessary assistance in connection therewith.

Article 9
CONFIDENTIALITY

9.1    Confidential Information.
9.1.1.    Confidentiality. All Confidential Information disclosed by a Party to
the other Party during the Agreement Term shall be used by the receiving Party
solely in connection with the activities contemplated by this Agreement, shall
be maintained in confidence by the receiving Party and shall not otherwise be
disclosed by the receiving Party to any other person, firm, or agency,
governmental or private (other than a Party’s Affiliates), without the prior
written consent of the disclosing Party. Acceleron and Celgene each agrees that
it shall provide Confidential Information received from the other Party only to
its employees, consultants and advisors, and to the employees, consultants and
advisors of such Party’s Affiliates or Sublicensees, and Third Parties acting on
behalf of such Party, who have a need to know and have an obligation to treat
such information and materials as confidential, which obligations are no less
stringent than those contained in this Article 9. Each Party shall be
responsible for a breach of this Article 9 by its Affiliates, Sublicensee, Third
Parties acting on behalf of such Party, and their respective employees,
consultants and advisors. All obligations of confidentiality imposed under this
Article 9 shall expire [* * *].
9.1.2    Authorized Disclosure. Notwithstanding the provisions of Sections
9.1.1, 9.2, or 9.3, each Party may disclose Confidential Information belonging
to the other Party to the extent such disclosure is reasonably necessary to:
(a)    comply with Applicable Laws (including the rules and regulations of the
Securities and Exchange Commission or any national securities exchange) and with
judicial process;
(b)    Prosecute Patent Rights as contemplated by this Agreement;

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(c)    defend or prosecute litigation in accordance with Article 8; provided
that the receiving Party provides prior written notice of such disclosure to the
disclosing Party and takes reasonable and lawful actions to avoid or minimize
the degree of such disclosure;
(d)    make filings and submissions to, or correspond or communicate with, any
Regulatory Authority or clinical registry, including for purposes of obtaining
authorizations to conduct Clinical Trials of, and to Commercialize, Licensed
Products pursuant to this Agreement; and
(e)    exercise its rights hereunder (including, with respect to Celgene,
disclosures to potential Sublicensees); provided such disclosure is covered by
terms of confidentiality similar to those set forth herein.
In the event a Party shall deem it reasonably necessary to disclose Confidential
Information belonging to the other Party pursuant to this Section 9.1.2, such
Party shall (i) to the extent possible give reasonable advance notice of such
disclosure to the other Party sufficiently prior to making such disclosure so as
to allow the other Party adequate time to take whatever action it may deem
appropriate to protect the confidentiality of the information, (ii) provide
reasonable assistance to the other Party with respect thereto, and (iii) take
reasonable measures to ensure confidential treatment of such information.
9.1.3    Acceleron’s Use of Confidential Information. Celgene acknowledges the
fact that as a private company, Acceleron shall, from time to time, engage in
fundraising activities with private investors. Acceleron may disclose this
Agreement, including its terms and subject matter, under terms of
confidentiality no less strict than those contained in this Agreement, to such
investors or potential investors (including potential acquirers) in or potential
licensees of Acceleron conducting due diligence in each instance. Acceleron
shall provide Celgene with a list of all such persons executing such
confidentiality agreements and shall be responsible for a breach of this Article
9 by such persons. Celgene shall permit a copy of this Agreement to be provided
to Salk as a requirement of the Salk License, such copy to be considered
confidential information under the Salk License and to be redacted to the extent
permitted under the Salk License, which redaction shall be subject to the prior
written approval of Celgene.
9.1.4    ACE-536 Agreement. The Parties acknowledge and agree that Confidential
Information disclosed pursuant to this Agreement may have application to the
Parties’ rights and obligations under the ACE-536 Agreement and vice versa.
Therefore, the Parties agree that information can be deemed Confidential
Information under this Agreement and “Confidential Information” under the
ACE-536 Agreement and that such information will be subject to the
confidentiality and non-use obligations of both agreements.
9.1.5    Joint Technology. The Parties agree that, in order to effectuate the
provisions of Section 4.6.2, subject to any exclusive licenses granted
hereunder, (a) the non-use provisions of this Article 9 shall not apply to each
Party’s use of Joint Technology, and (b) each Party

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may disclose the Joint Technology to Third Parties who are under terms of
confidentiality no less strict than those contained in this Agreement.

9.2    Publication Review. Except as required by Applicable Law or, subject to
the last sentence of this Section, as may be permitted under any agreement
identified on Schedule 2.8, from and after the Effective Date, Celgene shall
have the sole right to publish or present the results of any work relating to
the Licensed Products or Licensed Compounds; provided that Acceleron shall have
the right to publish or present works relating solely to PH Field Development
Activities or the Sotatercept Licensed Compounds or Sotatercept Licensed
Products, in each case, in the PH Field, subject to the other provisions of this
Section 9.2 (the Party entitled to publish pursuant to this Section being
hereafter referred to as the “Publishing Party”). The Publishing Party shall
publish or present such results in a manner consistent with the publication
strategy developed by either the Joint Development Committee or the Joint
Commercialization Committee. The Publishing Party shall provide to the other
Party for review any (a) abstracts, posters and slide presentations prior to any
scientific meetings, and such other Party shall have at least [* * *] Business
Days to provide feedback to such other Party, and (b) primary and final
manuscripts and review articles prior to journal submission, and such other
Party shall have at least [* * *] Business Days to provide feedback. The Party
that is not the Publishing Party may require that its Confidential Information
that may be disclosed in any such proposed publication or presentation be
deleted prior to such publication or presentation. Except to the extent a
publication or presentation relates solely to PH Field Development Activities or
a Sotatercept Licensed Compound or a Sotatercept Licensed Product in the PH
Field, Acceleron’s right to publish hereunder will be subject to the prior
consent of Celgene, such consent not to be unreasonably withheld or delayed and
which consent shall be deemed given if Celgene has not objected to any such
publication within the applicable [* * *] Business Day periods described above.
With respect to any publication or presentation that relates solely to PH Field
Development Activities or a Sotatercept Licensed Compound or a Sotatercept
Licensed Product in the PH Field, such publication or presentation will not
require Celgene’s prior consent, provided that in addition to deleting any
Confidential Information of Celgene as provided above, Acceleron shall delete
any other information the publication or presentation of which [* * *]. If (x) a
Third Party that is a party to an agreement identified on Schedule 2.8 is
permitted to publish or present the results of any work conducted by such Third
Party pursuant to such agreement and relating to the Licensed Products or
Licensed Compounds, and (y) such Third Party is required to present such
publication or presentation to Acceleron for prior review or approval, then (1)
to the extent that Acceleron is permitted to disclose to Celgene such
publications or presentations, Acceleron shall disclose such publications or
presentations to Celgene, (2) to the extent that Acceleron is not permitted to
disclose to Celgene such publications or presentations, Acceleron shall notify
Celgene in the event such a publication or presentation has been submitted to
Acceleron by such a Third Party, and (3) with respect to such publications or
presentations, to the extent such relate to Licensed Compounds and Licensed
Products other than Sotatercept Licensed Compounds and Sotatercept Licensed
Products in the PH Field, (regardless of whether they were disclosed to Celgene
or Celgene was merely notified of them), Acceleron shall take any action
requested by Celgene, including withholding consent to such publication or
presentation, to the extent Acceleron has the right to take such action under
the applicable agreement with such Third Party.
    

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9.3    Public Announcements and Use of Names. No disclosure of the existence of,
or the terms of, this Agreement may be made by either Party, and no Party shall
use the name, trademark, trade name or logo of the other Party or its employees
in any publicity, news release or disclosure relating to this Agreement or its
subject matter, in each case, without the prior written permission of the other
Party, except as may be required by law or expressly permitted by the terms
hereof, including Section 9.1.2. A press release announcing this Agreement is
attached to this Agreement as Schedule 9.3, which may be released by either
Party on the date agreed to by the Parties. Except for issuing such press
release and subsequent announcements of the information contained in such press
release, neither Party shall originate any publicity, news release or public
announcements, written or oral, whether to the public or press, stockholders or
otherwise, relating to the execution of this Agreement, the subject matter of
this Agreement or any activities contemplated hereby, any of the terms of this
Agreement, or any amendment hereto without the prior written consent of the
other Party, except as may be required by law or expressly permitted by the
terms hereof, including Section 9.1.2. Notwithstanding the foregoing, Celgene,
in its sole discretion, may determine the timing and content of any press
release with respect to activities conducted hereunder beginning with the Phase
2B Clinical Trials with respect to each Licensed Compound or Licensed Product
and all activities thereafter; provided that Celgene may not use Acceleron’s
name in any such press release without the prior written consent of Acceleron,
except for the limited purpose of identifying Acceleron as the licensor of the
Acceleron Technology, the party conducting the Phase 1 Clinical Trials and Phase
2A Clinical Trials, the party Developing and/or Commercializing Sotatercept
Licensed Compounds and Sotatercept Licensed Products in the PH Field or for
purpose of republishing materials that have previously been published in
accordance with this Section 9.3; provided further that Acceleron may, (a) to
the extent required by applicable securities laws, issue any press release with
respect to activities conducted hereunder beginning with the Phase 2B Clinical
Trials with respect to each Licensed Compound or Licensed Product or (b)
determine the timing and content of any press release relating solely to PH
Field Development Activities, in each case so long as Acceleron provides
Celgene: (i) with at least [* * *] Business Days’ prior written notice to review
and provide feedback to Acceleron on the content of such disclosure, which
feedback Acceleron shall consider in good faith; and (ii) the right to require
that its Confidential Information [* * *] be redacted from such disclosure.
Notwithstanding the foregoing, once a public announcement is approved in
accordance with this Section 9.3, a Party may reuse and subsequently disclose
the information in such public announcement and may continue to disclose the
contents of such public announcement without resubmitting such materials for
further approval; provided that such Party does not materially change content
and/or the manner in which the name, trademark, trade name or logo of the other
Party is used.

Article 10
TERM AND TERMINATION

10.1    Term. The term of this Agreement shall commence on the Amended and
Restated Effective Date and expire, unless this Agreement is terminated earlier
in accordance with this Article 11, on a country-by-country basis, upon the
latest to occur of the following: (a) the expiration of the Royalty Term with
respect to all Licensed Products in the Celgene Field in such country in the
Territory, (b) the expiration of the PH Field Royalty Term with respect to all
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the PH Field in such country in the Territory and (c) Celgene has exercised or
forfeited its option with regard to each Option Compound. For the avoidance of
doubt, both Sections 10.1(a) and (b) shall be deemed to have occurred on the
date on which no Development or Commercialization activities for any Licensed
Compound or Licensed Product in the Field are ongoing and, according to the
Joint Development Committee and Joint Commercialization Committee, no additional
Development or Commercialization activities, respectively, are expected to
commence. Upon the occurrence of the events described in clause (a) above, all
licenses granted by Acceleron under this Agreement for such Licensed Products or
Licensed Compounds in the Celgene Field in such country shall become fully
paid-up, perpetual, non-exclusive, sublicensable, irrevocable, royalty-free
licenses. Upon the occurrence of the events described in clause (b) above, all
licenses granted by Celgene under this Agreement for Sotatercept Licensed
Compounds or Sotatercept Licensed Products in the PH Field in the such country
shall become fully paid-up, perpetual, non-exclusive, sublicensable,
irrevocable, royalty-free licenses.

10.2    Termination for Cause.
10.2.1.    Cause for Termination. This Agreement may be terminated at any time
during the Agreement Term:
(a)    upon written notice by either Party if the other Party (the “Breaching
Party”) is in breach of its material obligations hereunder and has not cured
such breach within [* * *] (or [* * *] for breaches of payment obligations)
after notice requesting cure of the breach; provided that, notwithstanding the
foregoing, in the event of a breach of a material obligation that is capable of
being cured, but is not reasonably capable of being cured within the [* * *]
cure period, if the Breaching Party (i) proposes within such [* * *] period a
written plan to cure such breach within a defined time frame, and (ii) makes
good faith efforts to cure such default and to implement such written cure plan,
then the non-breaching Party may not terminate this Agreement for so long as the
Breaching Party is diligently pursuing such cure in accordance with such plan;
or
(b)    by either Party upon the filing or institution of bankruptcy,
reorganization, liquidation or receivership proceedings, or upon an assignment
of a substantial portion of the assets for the benefit of creditors by the other
Party; provided, however, that in the event of any involuntary bankruptcy or
receivership proceeding such right to terminate shall only become effective if
the Party consents to the involuntary bankruptcy or receivership or such
proceeding is not dismissed within [* * *] after the filing thereof. Celgene
acknowledges that pursuant to the Salk License, Salk may terminate the Salk
License immediately with no further notice obligation or opportunity to cure if
Acceleron becomes insolvent, makes an assignment for the benefit of creditors,
has a petition in bankruptcy filed for or against it or has a receiver or
trustee in bankruptcy or similar officer appointed to take charge of all or part
of Acceleron’s property; provided that the provisions of Section 4.7.4 hereof
would apply.

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10.2.2.    Effect of Termination for Cause.
(a)    Termination by Acceleron. Without limiting any other legal or equitable
remedies that Acceleron may have, if Acceleron terminates this Agreement in
accordance with Section 10.2.1, then the effects of such termination set forth
in Section 10.5.1 shall be effective and take place.
(b)    Termination by Celgene. Without limiting any other legal or equitable
remedies that Celgene may have, if Celgene terminates this Agreement in
accordance with Section 10.2.1, then (i) the licenses granted to Acceleron
pursuant to Section 4.2 shall terminate, (ii) the right of reference granted to
Celgene by Acceleron under Section 4.5.1 shall become perpetual and irrevocable,
(iii) Acceleron shall no longer retain the rights set forth in Section 4.3, (iv)
the licenses granted to Celgene under Section 4.1 shall continue in perpetuity,
(v) as between the Parties and without limiting any other provision of this
Agreement, Celgene shall be solely responsible for all Commercialization of
Licensed Products in the Field (including booking all sales, and managing the
sale, invoicing and distribution system for Licensed Products in the Field),
such Commercialization to be conducted in Celgene’s sole discretion, (vi)
Acceleron shall assign to Celgene all of its rights, title and interest in
Product Trademarks for Sotatercept Licensed Products in the PH Field, (vii)
Acceleron shall transfer to Celgene ownership of any NDAs or Regulatory
Approvals then in Acceleron’s name related to Sotatercept Licensed Compounds or
Sotatercept Licensed Products in the PH Field and notify the appropriate
Regulatory Authorities and take any other action reasonably necessary to effect
such transfer of ownership; provided that if ownership of an NDA or Regulatory
Approval cannot be transferred to Celgene in any country, Acceleron hereby
grants (effective only upon any such termination of this Agreement) to Celgene a
permanent, exclusive (even as to Acceleron) and irrevocable right of access and
reference to such NDAs and Regulatory Approvals for Sotatercept Licensed
Compounds and Sotatercept Licensed Products in such country in the PH Field,
(viii) Celgene shall pay Acceleron [* * *] percent [* * *] of the Celgene Field
Royalty Rate (calculated as if the relevant Licensed Product is in the Celgene
Field and Celgene is the Distributing Party for such Licensed Product) on all
Net Sales of Licensed Products in the Field in a country in the Territory
occurring after the effective date of termination for (A) with respect to
Licensed Products in the Celgene Field, the duration of the Royalty Term for
such Licensed Product in such country and (B) with respect to Sotatercept
Licensed Products in the PH Field, the duration of the PH Field Royalty Term for
such Sotatercept Licensed Product in such country; (ix) Celgene shall have no
obligation to pay any milestones arising under this Agreement after the date of
such termination; (x) Acceleron’s obligations under Article 6 (Exclusivity)
shall survive such termination for as long as Celgene is paying royalties
pursuant hereto; and (xi) Acceleron shall continue to be solely responsible for
all royalty, milestone, and other payments owed to Salk or any other third party
licensor pursuant to an agreement executed by Acceleron prior to the Effective
Date (or, with respect to any Option Compound, prior to the date that such
Option Compound is deemed a Licensed

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Compound in accordance with Article 7); provided that, if Acceleron is the
Breaching Party and Celgene terminates this Agreement in accordance with Section
10.2.1(a) for a breach by Acceleron of its material obligations under Article 6
(Exclusivity) or if Acceleron breaches such Article 6 (Exclusivity) following
termination during the period such obligations survive as provided in this
Section 10.2.1(b), then Celgene shall have no further obligation to pay any
royalties hereunder based on Celgene Field Net Sales arising after the date of
such termination, but Celgene shall be responsible for paying royalties based on
PH Field Net Sales and any royalties due to Salk and other Third Parties
pursuant to Section 5.6.3(c) with respect to activities of Celgene in exercising
such licenses.

10.3    Termination for Convenience. At any time, Celgene may terminate this
Agreement, on a country-by-country or Licensed Product-by-Licensed Product basis
or in its entirety, for any reason, upon one hundred eighty (180) days’ advance
written notice to Acceleron.

10.4    Termination for Failure to Meet End Points. If a Licensed Compound or
Licensed Product fails to meet the end point criteria set by the Joint
Development Committee pursuant to Section 3.3 for a particular Clinical Trial or
Development activity, Celgene may terminate this Agreement, on a Licensed
Product-by-Licensed Product basis or in its entirety, upon 45 days’ advance
written notice to Acceleron.

10.5    Other Effects of Termination.
10.5.1.    By Acceleron for Cause. In the event that Acceleron terminates this
Agreement for cause under Section 10.2.1:
(a)    License and Assignment.
(i)    All licenses granted to Celgene under this Agreement with respect to the
applicable country or Licensed Product shall terminate and the license granted
by Celgene to Acceleron in clause (a) of Section 4.2 shall become irrevocable,
shall continue in perpetuity and shall be royalty-bearing as follows: for each
Sotatercept Licensed Product in the PH Field, Acceleron shall pay Celgene [* *
*] percent [* * *] of the PH Field Royalty Rate (calculated as if Acceleron is
the Distributing Party for the relevant Sotatercept Licensed Product) on PH
Field Net Sales of such Sotatercept Licensed Product in the PH Field in a
country in the Territory occurring after the effective date of termination for
the duration of the PH Field Royalty Term of such Sotatercept Licensed Product
in such country. In addition, the right of reference granted to Acceleron by
Celgene under Section 4.5.2 shall become perpetual and irrevocable. Celgene’s
obligations under Section 6.1.6 shall survive such termination for as long as
Acceleron is paying royalties pursuant thereto.

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(ii)    In addition to and without limiting any of the rights granted and
maintained pursuant to Section 10.5.1(a)(i), Celgene (a) hereby grants
(effective only upon any such termination of this Agreement) to Acceleron a
worldwide, non-exclusive, non-transferable license, with the right to sublicense
(under the same terms that Acceleron may sublicense its rights pursuant to
Section 4.4.2), under the Celgene Technology to offer for sale, sell, make, have
made, use and import Licensed Compounds (and Option Compounds to the extent that
they have become Licensed Compounds at the time of termination pursuant to
Section 7.2) and Licensed Products in the Celgene Field in the Territory, which
license shall be (i) royalty-free if Acceleron terminates this Agreement for
cause under Section 10.2.1 for a breach by Celgene of its material obligations
under Article 6 (Exclusivity) and (ii) royalty-bearing for Celgene Field Net
Sales in the event that Acceleron terminates this Agreement for any other cause
under Section 10.2.1 as follows: for each Licensed Product in the Celgene Field,
Acceleron shall pay Celgene [* * *] percent [* * *] of the Celgene Field Royalty
Rate (calculated as if Celgene was the Distributing Party for the relevant
Licensed Product) on Celgene Field Net Sales of such Licensed Product in the
Celgene Field in a country in the Territory occurring after the effective date
of termination for the duration of the Royalty Term for such Licensed Product in
such country; (b) shall assign or sublicense to Acceleron, to the extent
possible and as requested by Acceleron, Celgene’s rights and obligations under
any Third Party licenses entered into pursuant to Sections 5.6.3(b) or 5.6.3(c),
(c) shall assign to Acceleron all of its rights, title and interest in Product
Trademarks, and (d) shall transfer to Acceleron ownership of any NDAs or
Regulatory Approvals then in Celgene’s name related to Licensed Compounds or
Licensed Products and notify the appropriate Regulatory Authorities and take any
other action reasonably necessary to effect such transfer of ownership. If
ownership of an NDA or Regulatory Approval cannot be transferred to Acceleron in
any country, Celgene hereby grants (effective only upon any such termination of
this Agreement) to Acceleron a permanent, exclusive (even as to Celgene) and
irrevocable right of access and reference to such NDAs and Regulatory Approvals
for Licensed Compounds and Licensed Products in such country in the Field. The
royalties to be paid by Acceleron to Celgene shall be paid under the terms
specified in Section 5.6.1(a), in each case substituting “Acceleron” for
“Celgene” and vice versa with respect to all obligations and definitions, and
otherwise mutatis mutandis.
(b)    Commercialization of Licensed Products. As of and following the effective
date of termination, as between the Parties and without limiting any other
provision of this Agreement, Acceleron shall be solely responsible for all
Commercialization of Licensed Products in the Field (including booking all
sales, and managing the sale, invoicing and distribution system for Licensed
Products in the Field), such Commercialization to be conducted in Acceleron’s
sole discretion.

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(c)    Transfer of Materials. In the event Acceleron exercises its rights
pursuant to Section 10.5.1, Celgene shall negotiate in good faith with Acceleron
regarding Celgene transferring to Acceleron, at Acceleron’s cost, materials
developed under this Agreement in the course of Developing and Commercializing
Licensed Compounds or Licensed Products that are directly related to Licensed
Compounds or Licensed Products to the extent provided in and in accordance with
such agreement.
(d)    Confidential Information. Notwithstanding Section 9.1.1, which provides
that obligations of confidentiality shall expire [* * *] years following
termination or expiration of this Agreement, for so long as the Celgene
Know-How, Celgene Improvements or Celgene Collaboration IP to be licensed to
Acceleron pursuant to Section 10.5.1 remain Confidential Information,
Acceleron’s obligations of confidentiality pursuant to Article 9 shall survive
and continue in full force and effect.
(e)    Continuity of Supply. Subject to the terms and conditions of any other
agreement between the Parties, in the event that Celgene has begun Manufacture
of Clinical Supplies or Commercial Supplies pursuant to Section 2.4, then at
Acceleron’s request, Celgene shall continue to Manufacture and supply Acceleron
with such Clinical Supplies or such Commercial Supplies, as applicable, at [* *
*], for an additional [* * *] after termination for Clinical Supplies and for an
additional [* * *] after termination for Commercial Supplies; provided, however,
that Celgene shall not be obligated to Manufacture or supply such Clinical
Supplies or Commercial Supplies in excess of the greater of (i) the anticipated
amounts of such supply as set forth in the applicable Development Plan/Budget or
Commercialization Plan/Budget for such [* * *] or (ii) the amount of such
Clinical Supplies or Commercial Supplies Manufactured by Celgene in the [* * *]
prior to termination and provided further that, at Acceleron’s request, Celgene
shall, at its own expense, promptly conduct a technology transfer to Acceleron
or its designee of all Celgene Technology required for Acceleron to Manufacture
and supply (or have Manufactured and supplied) Clinical Supplies or Commercial
Supplies of Licensed Compounds or Licensed Products and shall provide reasonable
support to assist in such transfer of the Manufacturing process. In the event
that the Clinical Supplies or Commercial Supplies are being Manufactured by a
Third Party under contract, to the extent permitted by the terms of such
contract, Celgene shall assign such contracts to Acceleron. For all future Third
Party Manufacturing contracts related to the Licensed Compounds or Licensed
Products, Celgene shall use Commercially Reasonable Efforts to ensure that such
contracts are assignable to Acceleron in the event of termination of this
Agreement as provided in Section 10.5.1.
10.5.2.    By Celgene for Convenience or for Failure to Meet Endpoints. In the
event that Celgene terminates this Agreement for convenience under Section 10.3
or for failure to meet end points under Section 10.4:
(a)    License and Assignment.

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(i)    All licenses granted to Celgene under this Agreement with respect to the
applicable country or Licensed Product shall terminate. In addition, the right
of reference granted to Acceleron by Celgene under Section 4.5.2 shall become
perpetual and irrevocable and Celgene’s obligations under Section 6.1.6 shall
survive such termination.
(ii)    In addition to and without limiting any of the rights granted and
maintained pursuant to Section 10.5.2(a)(i), Celgene (a) hereby grants
(effective only upon any such termination of this Agreement) to Acceleron a
perpetual, irrevocable, worldwide, exclusive, non-transferable and
royalty-bearing license, with the right to sublicense (under the same terms that
Celgene may sublicense its rights pursuant to Section 4.4.2), under the Celgene
Technology to offer for sale, sell, make, have made, use and import Licensed
Compounds (and Option Compounds to the extent that they have become Licensed
Compounds at the time of termination pursuant to Section 7.2) and Licensed
Products in the Field in the Territory; (b) shall assign or sublicense to
Acceleron, to the extent possible and as requested by Acceleron, Celgene’s
rights and obligations under any Third Party licenses entered into pursuant to
Sections 5.6.3(b) or 5.6.3(c), (c) shall assign to Acceleron all of its rights,
title and interest in Product Trademarks, and (d) shall transfer to Acceleron
ownership of any NDAs or Regulatory Approvals then in Celgene’s name related to
Licensed Compounds or Licensed Products and notify the appropriate Regulatory
Authorities and take any other action reasonably necessary to effect such
transfer of ownership. If ownership of an NDA or Regulatory Approval cannot be
transferred to Acceleron in any country, Celgene hereby grants (effective only
upon any such termination of this Agreement) to Acceleron a permanent, exclusive
(even as to Celgene) and irrevocable right of access and reference to such NDAs
and Regulatory Approvals for Licensed Compounds and Licensed Products in such
country in the Field.
(iii)    With respect to each Licensed Product in the Field, Acceleron shall pay
to Celgene the PH Field Royalty Rate (calculated as if the relevant Licensed
Product is in the PH Field and Acceleron is the Distributing Party for such
Licensed Product) on the Net Sales of such Licensed Product in the Field in a
country in the Territory occurring after the effective date of termination for
(A) with respect to Licensed Products in the Celgene Field, the duration of the
Royalty Term for such Licensed Product in such country and (B) with respect to
Sotatercept Licensed Products in the PH Field, the duration of the PH Field
Royalty Term for such Sotatercept Licensed Product in such country.
(b)    Termination Agreement. In addition to and without limiting any of the
rights granted and maintained pursuant to this Section 10.5.2, the Parties shall
negotiate in good faith and enter into a termination agreement effective as of
the effective date

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of termination which would further memorialize and elaborate upon the terms of
this Section 10.5.2 and set forth other customary terms and conditions intended
to facilitate Acceleron’s Development and Commercialization of Licensed
Compounds and Licensed Products in the Field in the Territory, subject to
restrictions on Use in Anemia. Following such termination, Acceleron shall be
required to continue to pay to Celgene the royalty set forth in Section (a) and
such payment terms relating to such royalty, consistent with the payment terms
set forth in this Agreement, would be included in such termination agreement.
(c)    Commercialization of Licensed Products. As of and following the effective
date of termination, as between the Parties and without limiting any other
provision of this Agreement, Acceleron shall be solely responsible for all
Commercialization of Licensed Products in the Field (including booking all
sales, and managing the sale, invoicing and distribution system for Licensed
Products in the Field), such Commercialization to be conducted in Acceleron’s
sole discretion.
(d)    Confidential Information. Notwithstanding Section 9.1.1, which provides
that obligations of confidentiality shall expire [* * *] years following
termination or expiration of this Agreement, for so long as the Celgene
Know-How, Celgene Improvements or Celgene Collaboration IP to be licensed to
Acceleron pursuant to Section 10.5.1 remain Confidential Information,
Acceleron’s obligations of confidentiality pursuant to Article 9 shall survive
and continue in full force and effect.
(e)    Continuity of Supply. Except in the event of a termination of this
Agreement pursuant to Section 10.4, in the event that Celgene has begun
Manufacture of Clinical Supplies or Commercial Supplies pursuant to Section 2.4,
then at Acceleron’s request, Celgene shall continue to Manufacture and supply
Acceleron with such Clinical Supplies or such Commercial Supplies, as
applicable, at [* * *], for an additional [* * *] after termination for Clinical
Supplies and for an additional [* * *] after termination for Commercial
Supplies; provided, however, that Celgene shall not be obligated to Manufacture
or supply such Clinical Supplies or Commercial Supplies in excess of the greater
of (i) the anticipated amounts of such supply as set forth in the applicable
Development Plan/Budget or Commercialization Plan/Budget for such [* * *] or
(ii) the amount of such Clinical Supplies or Commercial Supplies Manufactured by
Celgene in the [* * *] prior to termination and provided further that, at
Acceleron’s request, Celgene shall, at its own expense, promptly conduct a
technology transfer to Acceleron or its designee of all Celgene Technology
required for Acceleron to Manufacture and supply (or have Manufactured and
supplied) Clinical Supplies or Commercial Supplies of Sotatercept Licensed
Compounds or Sotatercept Licensed Products and shall provide reasonable support
to assist in such transfer of the Manufacturing process. In the event that the
Clinical Supplies or Commercial Supplies are being Manufactured by a Third Party
under contract, to the extent permitted by the terms of such contract, Celgene
shall assign such contracts to Acceleron. For all future Third Party
Manufacturing contracts related to the Licensed Compounds or Licensed Products,
Celgene shall use Commercially

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Reasonable Efforts to ensure that such contracts are assignable to Acceleron in
the event of termination of this Agreement as provided in Section 10.5.1. In the
event Acceleron exercises its rights pursuant to this Section 10.5.2(e), Celgene
shall negotiate in good faith with Acceleron regarding Celgene transferring to
Acceleron, at Acceleron’s cost, materials developed under this Agreement in the
course of Developing and Commercializing Licensed Compounds or Licensed Products
that are directly related to Licensed Compounds or Licensed Products to the
extent provided in and in accordance with such agreement.

10.6    Sell-Down. If Celgene, its Affiliates or Sublicensees at termination of
this Agreement possess Licensed Product, have started the Manufacture thereof or
have accepted orders therefor, Celgene, its Affiliates or Sublicensees shall
have the right, for up to [* * *] following the date of termination, to sell
(or, if Acceleron is the Distributing Party, to have the Distributing Party or
its designee sell) their inventories thereof that were allocated for the Celgene
Field, complete the Manufacture thereof and Commercialize such
fully-Manufactured Licensed Product in the Celgene Field, in order to fulfill
such accepted orders or distribute such fully-Manufactured Licensed Product,
subject to the obligation of Celgene to pay Acceleron the royalty payments as
provided in Article 5 of this Agreement.

10.7    Transfer of Records. Upon expiration of this Agreement or in the event
that Celgene terminates this Agreement for cause under Section 10.2.1, Acceleron
will continue to maintain all records described in Section 2.2 or transfer them
to Celgene, as requested by Celgene.

10.8    Rights in Bankruptcy. All rights and licenses granted under or pursuant
to this Agreement by Acceleron or Celgene, including Article 4, are, and shall
otherwise be deemed to be, for purposes of Section 365(n) of the U.S. Bankruptcy
Code or analogous provisions of Applicable Law outside the United States,
licenses of right to “intellectual property” as defined under Section 101 of the
U.S. Bankruptcy Code or analogous provisions of Applicable Law outside the
United States (hereinafter “IP”). The Parties agree that Celgene or Acceleron,
as applicable, as licensee of such rights under this Agreement, shall retain and
may fully exercise all of its rights and elections under the U.S. Bankruptcy
Code or any other provisions of Applicable Law outside the United States that
provide similar protection for IP. Upon the bankruptcy of Acceleron or Celgene,
the non-bankrupt Party shall further be entitled to a complete duplicate of (or
complete access to, as appropriate) any such IP, and such IP, if not already in
such Party’s possession, shall be promptly delivered to such Party.

10.9    Effect of Expiration or Termination; Survival. Expiration or termination
of this Agreement shall not relieve the Parties of any obligation accruing prior
to such expiration or termination. The provisions of Article 9, Article 10,
Article 12 and Sections 4.4.4, 4.6, 4.7.4, 11.5, 11.6, 11.7, as well as Sections
8.2, 8.3, 8.4.4 and 8.6 (but only to the extent that Celgene’s exclusive license
survives pursuant to Section 10.2.2(b)) shall survive any expiration or
termination of this Agreement. Except as set forth in this Article 10, upon
termination or expiration of this Agreement

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all other rights and obligations cease. Any expiration or early termination of
this Agreement shall be without prejudice to the rights of either Party against
the other accrued or accruing under this Agreement before termination.

Article 11
REPRESENTATIONS AND WARRANTIES; INDEMNIFICATION

11.1    Mutual Representations and Warranties. Each Party represents and
warrants to the other Party that as of the Effective Date and the Amended and
Restated Effective Date of this Agreement:
11.1.1.    It is duly organized and validly existing under the laws of its
jurisdiction of incorporation or formation and has full corporate or other power
and authority to enter into this Agreement and to carry out the provisions
hereof. Further, except for any Regulatory Approvals, pricing or reimbursement
approvals, manufacturing approvals or similar approvals necessary for the
Development, Manufacture or Commercialization of the Licensed Compounds and
Licensed Products, all necessary consents, approvals and authorizations of all
government authorities required to be obtained by such Party as of the Effective
Date in connection with the execution, delivery and performance of this
Agreement have been obtained by the Effective Date.
11.1.2.    It is duly authorized to execute and deliver this Agreement and to
perform its obligations hereunder, and the person or persons executing this
Agreement on its behalf has been duly authorized to do so by all requisite
corporate action.
11.1.3.    This Agreement is legally binding upon it and enforceable in
accordance with its terms. The execution, delivery and performance of this
Agreement by it does not conflict with any agreement, instrument or
understanding, oral or written, to which it is a party and by which it may be
bound.

11.2    Acceleron Representations, Warranties and Covenants. Acceleron
represents and warrants to Celgene that as of the Effective Date, or covenants,
as applicable, that:

11.2.1.    Acceleron Controlled the Acceleron Patent Rights existing as of the
Effective Date and was entitled to grant the licenses specified under the
Original Agreement. The Acceleron Patent Rights existing as of the Effective
Date constituted all of the Patent Rights Controlled by Acceleron as of the
Effective Date that relate to or are necessary or useful to Develop, Manufacture
or Commercialize a Licensed Compound or a Licensed Product in the Field.
Acceleron has not previously assigned, transferred, conveyed or otherwise
encumbered its right, title and interest in the Acceleron Technology in a manner
that conflicts with any rights granted to Celgene hereunder. During the
Agreement Term, Acceleron shall not encumber the rights granted to Celgene
hereunder with respect to the Acceleron Patent Rights.
11.2.2.    Acceleron Controlled the Option Patent Rights existing as of the
Effective Date and was entitled to grant the options for licenses specified
under the Original Agreement. During

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the Agreement Term, Acceleron shall not encumber the Option Patent Rights in a
manner that conflicts with any rights granted to Celgene hereunder.
11.2.3.    To the best knowledge of Acceleron and its Affiliates, there was no
actual or threatened infringement of the Acceleron Patent Rights or the Option
Patent Rights in the Celgene Field by any Third Party or any other infringement
or threatened infringement that would adversely affect Celgene’s rights under
the Original Agreement.
11.2.4.    There were no claims, judgments or settlements against or owed by
Acceleron or its Affiliates or pending or, to the best knowledge of Acceleron
and its Affiliates, threatened claims or litigation relating to the Acceleron
Technology that would impact activities under the Original Agreement.
11.2.5.    The Salk License, as set forth in Exhibit A, is in full force and
effect and has not been modified or amended.
11.2.6.    Neither Acceleron nor, to the best knowledge of Acceleron, Salk was
in default with respect to a material obligation under, and neither such party
had claimed or had grounds upon which to claim that the other party is in
default with respect to a material obligation under, the Salk License.
11.2.7.    To the best knowledge of Acceleron, the Salk Patent Rights were not,
prior to or on the Effective Date, subject to any restrictions or limitations
except as set forth in the Salk License, a true and correct copy of which is
attached as Exhibit A.
11.2.8.    Acceleron had not waived or allowed to lapse any of its rights under
the Salk License with respect to Licensed Compounds or Licensed Products, and no
such rights had lapsed or otherwise expired or been terminated.
11.2.9.    As of the Effective Date, neither Acceleron nor any of its respective
employees or, to the best knowledge of Acceleron or its Affiliates, its agents,
in their capacity as such, had been disqualified or debarred by the FDA,
pursuant to 21 U.S.C. §§ 335(a) or (b), or been charged with or convicted under
United States law for conduct relating to the development or approval, or
otherwise relating to the regulation of any Licensed Product under the Generic
Drug Enforcement Act of 1992, or any other relevant law, rule, or regulation or
been disbarred, disqualified, or convicted under or for any equivalent or
similar applicable foreign law, rule, or regulation.
11.2.10.    ActRIIA is a “Primary Licensed Product” under the Salk License, and,
if ActRIIA becomes a “Secondary Licensed Product” under the Salk License,
Acceleron will continue to have the right to grant to Celgene a sublicense of
all of Acceleron’s rights under the Salk License to the extent set forth in this
Agreement without any alteration from the granted rights associated with a
“Primary Licensed Product,” except that the license from Salk becomes
non-exclusive.

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11.2.11.    The Acceleron Patent Rights, and to the best knowledge of Acceleron
or its Affiliates, the Salk Patent Rights, had been filed and diligently
prosecuted in accordance with all Applicable Laws in the Territory and had been
maintained, with all applicable fees with respect thereto having been paid.
11.2.12.    To the best knowledge of Acceleron or its Affiliates, each of the
issued Acceleron Patents Rights was valid and enforceable.
11.2.13.    To the best knowledge of Acceleron (after due investigation), there
had been no patent applications arising from research funded by [* * *] since
the effective date of [* * *], as described in [* * *] except for U.S. patent
application Nos. [* * *] and [* * *] and all foreign counterparts thereto and
all provisional applications, continuations, continuations-in-part, and
divisions thereof.
11.2.14.    For purposes of exercising its rights or performing its obligations
hereunder in Developing, Manufacturing and Commercializing Licensed Compounds or
Licensed Product [* * *], Celgene does not need access or a license to (a) the
patent rights specified in Section 11.2.13 or (b) to the best knowledge of
Acceleron or its Affiliates, any and all Know-How, Patent Rights, or other
intellectual property rights that were licensed to Acceleron or its Affiliates
or that they otherwise have access to but were not Controlled by Acceleron or
its Affiliates pursuant to the Original Agreement.
11.2.15.    Without limiting any other provision of this Agreement, Acceleron
will not conduct Development or Commercialization of Licensed Compounds or
Licensed Products in the Celgene Field except as expressly provided in this
Agreement without Celgene’s written consent.

11.3    Option Compound Representations and Warranties. Immediately prior to an
Option Compound becoming a “Licensed Compound” pursuant to Article 7, Acceleron
shall represent and warrant to Celgene the matters set forth in Section 11.2
with respect to such Option Compound or shall notify Celgene of which
representations and warranties, if any, are untrue.

11.4    Celgene Representations, Warranties and Covenants. Celgene represents
and warrants to Acceleron that as of the Effective Date, and to the best
knowledge of Celgene or its Affiliates, there were no claims, judgments or
settlements against or owed by Celgene or its Affiliates or pending or
threatened claims or litigation relating to the Celgene Technology that would
impact activities under this Agreement. Additionally, without limiting any other
provision of this Agreement, Celgene covenants that in the event that Acceleron
[* * *], Celgene will not [* * *] without Acceleron’s written consent.

11.5    Warranty Disclaimer. EXCEPT AS OTHERWISE EXPRESSLY PROVIDED IN THIS
AGREEMENT, NEITHER PARTY MAKES ANY REPRESENTATION OR EXTENDS ANY WARRANTY OF ANY
KIND, EITHER EXPRESS OR IMPLIED, TO THE OTHER PARTY WITH RESPECT TO ANY
TECHNOLOGY OR OTHER SUBJECT MATTER OF THIS

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AGREEMENT AND HEREBY DISCLAIMS ALL IMPLIED WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT WITH RESPECT TO ANY AND ALL
OF THE FOREGOING. EACH PARTY HEREBY DISCLAIMS ANY REPRESENTATION OR WARRANTY
THAT THE DEVELOPMENT, MANUFACTURE OR COMMERCIALIZATION OF ANY LICENSED COMPOUND,
OPTION COMPOUND OR LICENSED PRODUCT UNDER THIS AGREEMENT SHALL BE SUCCESSFUL.

11.6    No Consequential Damages. NEITHER PARTY HERETO SHALL BE LIABLE FOR
SPECIAL, INCIDENTAL, PUNITIVE OR CONSEQUENTIAL DAMAGES ARISING OUT OF THIS
AGREEMENT OR THE EXERCISE OF ITS RIGHTS HEREUNDER, INCLUDING LOST PROFITS
ARISING FROM OR RELATING TO ANY BREACH OF THIS AGREEMENT, REGARDLESS OF ANY
NOTICE OF SUCH DAMAGES. NOTHING IN THIS SECTION 11.6 IS INTENDED TO LIMIT OR
RESTRICT THE INDEMNIFICATION RIGHTS OR OBLIGATIONS OF EITHER PARTY OR TO LIMIT A
PARTY’S LIABILITY FOR BREACHES OF ITS OBLIGATION REGARDING [* * *].

11.7    Indemnification and Insurance.
11.7.1.    Indemnification by Celgene. Celgene shall indemnify, hold harmless,
and defend Acceleron, its Affiliates, and their respective directors, officers,
employees and agents and their respective successors, heirs and assigns
(“Acceleron Indemnitees”) from and against any and all Third Party claims,
suits, losses, liabilities, damages, costs, fees and expenses (including
reasonable attorneys’ fees and expenses of litigation) (collectively, “Losses”)
to the extent arising out of or resulting from (a) any breach of, or inaccuracy
in, any representation or warranty made by Celgene in this Agreement, or any
breach or violation of any covenant or agreement of Celgene in or pursuant to
this Agreement; (b) the negligence or willful misconduct by or of Celgene, its
Affiliates or Sublicensees, and their respective directors, officers, employees
and agents; and (c) any product liability claims (under any theory, including
actions in the form of tort, warranty or strict liability) relating to Celgene’s
Development, Manufacturing (other than Manufacture of Existing Drug Product
supplied by Celgene to Acceleron for use in connection with Development
activities under this Agreement, except to the extent such Losses arise out of
Celgene’s breach of its warranty with respect to Existing Drug Product in
Section 2.4.2), and Commercialization activities under this Agreement. Celgene
shall have no obligation to indemnify the Acceleron Indemnitees to the extent
that the Losses arise out of or result from, directly or indirectly, any breach
of, or inaccuracy in, any representation or warranty made by Acceleron in this
Agreement, or any breach or violation of any covenant or agreement of Acceleron
in or pursuant to this Agreement, or the negligence or willful misconduct by or
of any of the Acceleron Indemnitees. For clarity, any actions taken or not taken
by Acceleron at Celgene’s written direction with respect to Licensed Compounds
or Licensed Products pursuant to this Agreement shall constitute activities of
Celgene for purposes of this Section 11.7.1.

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11.7.2.    Indemnification by Acceleron. Acceleron shall indemnify, hold
harmless, and defend Celgene, its Affiliates, and their respective directors,
officers, employees and agents and their respective successors, heirs and
assigns (“Celgene Indemnitees”) from and against any and all Losses to the
extent arising out of or resulting from (a) any breach of, or inaccuracy in, any
representation or warranty made by Acceleron in this Agreement, or any breach or
violation of any covenant or agreement of Acceleron in or pursuant to this
Agreement; (b) the negligence or willful misconduct by or of Acceleron, its
Affiliates and their respective Sublicensees, and their respective directors,
officers, employees and agents; or (c) any product liability claims (under any
theory, including actions in the form of tort, warranty or strict liability)
relating to Acceleron’s Development, Manufacturing, and Commercialization
activities under this Agreement, including Acceleron’s use of Existing Drug
Product in connection with Development activities under this Agreement.
Acceleron shall have no obligation to indemnify the Celgene Indemnitees to the
extent that the Losses arise out of or result from, directly or indirectly, any
breach of, or inaccuracy in, any representation or warranty made by Celgene in
this Agreement, or any breach or violation of any covenant or agreement of
Celgene in or pursuant to this Agreement, or the negligence or willful
misconduct by or of any of the Celgene Indemnitees. For clarity, any actions
taken or not taken by Celgene at Acceleron’s written direction with respect to
Sotatercept Licensed Compounds or Sotatercept Licensed Products pursuant to
Section 2.3.3 or otherwise pursuant to this Agreement shall constitute
activities of Acceleron for purposes of this Section 11.7.2.
11.7.3.    Indemnification Procedure. In the event of any such claim against any
Celgene Indemnitee or Acceleron Indemnitee (individually, an “Indemnitee”), the
indemnified Party shall promptly notify the other Party in writing of the claim
and the indemnifying Party shall manage and control, at its sole expense, the
defense of the claim and its settlement. The Indemnitee shall cooperate with the
indemnifying Party and may, at its option and expense, be represented in any
such action or proceeding. The indemnifying Party shall not be liable for any
settlements, litigation costs or expenses incurred by any Indemnitee without the
indemnifying Party’s prior written authorization. Notwithstanding the foregoing,
if the indemnifying Party believes that any of the exceptions to its obligation
of indemnification of the Indemnitees set forth in Section 11.7.1 or 11.7.2 may
apply, the indemnifying Party shall promptly notify the Indemnitees, which may
be represented in any such action or proceeding by separate counsel at their
expense; provided that the indemnifying Party shall be responsible for payment
of such expenses if the Indemnitees are ultimately determined to be entitled to
indemnification from the indemnifying Party. Any other provision of this Article
11 to the contrary, no Indemnitee under this Agreement shall be required to
waive a conflict of interest under any applicable rules of professional ethics
or responsibility if such waiver would be required for a single law firm to
defend both the indemnifying Party and one or more Indemnitees. In such case,
the indemnifying Party shall provide a defense of the affected Indemnitees
through a separate law firm reasonably acceptable to the affected Indemnitees at
the indemnifying Party’s expense.
11.7.4.    Joint Defendants. If a product liability suit is brought against
either Party relating in any way to a Licensed Product or Licensed Compound, and
it is not clear from the

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allegations in the complaint or the known facts surrounding the allegations in
the complaint as to whether a claim exists for which there is a right of
indemnification pursuant to Section 11.7.1 or 11.7.2 above, then Celgene shall
be responsible for controlling the defense of such suit in the first instance.
During such period that Celgene is controlling such defense, with regard to the
costs of such defense, including attorneys’ fees, Celgene and Acceleron each
shall be responsible for [* * *] of all such costs. No settlement, consent
judgment or other voluntary final disposition of any such suit may be entered
into without the prior written consent of Acceleron, which consent shall not be
unreasonably withheld or delayed. If, at any time in the course of such suit, it
becomes apparent from discovery or otherwise that a claim exists for which
indemnification may be obtained in accordance with Section 11.7.1 or 11.7.2
above, then the indemnification provisions of either Section 11.7.1 or 11.7.2
above, whichever is applicable, and the indemnification procedures of Section
11.7.3 shall become applicable and govern further proceedings in the suit.
11.7.5.    Insurance. As of the Effective Date and throughout the term of this
Agreement, each Party shall procure and maintain, at its sole cost and expense,
commercial general liability insurance and products liability coverage (each
including broad form contractual liability coverage for such Party’s
indemnification obligation under Section 11.7.1 or 11.7.2 above, as applicable)
in amounts not less than [* * *] per incident and [* * *] annual aggregate;
provided that after approval of the first NDA by a Regulatory Authority for use
of a Licensed Product, such products liability coverage shall be increased to
not less than [* * *] per incident and [* * *] annual aggregate. Each Party
shall name the other Party as additional insureds on each such insurance policy
relating to this Agreement. Celgene may elect to self-insure all or parts of the
limits described above. The minimum amounts of insurance coverage required under
this Section 11.7.5 shall not be construed to create a limit of either Party’s
liability with respect to its indemnification obligation under Section 11.7.1 or
11.7.2 above, as applicable.
11.8    [* * *] Promptly following the completion, under the ACE-536 Agreement,
of the first Phase 2 Clinical Trial of a Licensed Product (as defined in the
ACE-536 Agreement) for myelofibrosis by Celgene, its Affiliate or Sublicensee
(as defined in the ACE-536 Agreement), the Parties [* * *].

Article 12
MISCELLANEOUS PROVISIONS

12.1    Dispute Resolution; Governing Law.
12.1.1.    Disputes. Unless otherwise set forth in this Agreement, in the event
of any dispute arising under this Agreement between the Parties, the Parties may
refer such dispute to the respective Executive Officers, and such Executive
Officers shall attempt in good faith to resolve such dispute. If the Parties are
unable resolve a given dispute pursuant to this Section 12.1.1 within [* * *]
days of referring such dispute to the Executive Officers, either Party shall be
free to pursue any remedy that may be available to it at law or in equity.

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12.1.2.    Jurisdiction. Each Party hereby (a) irrevocably submits to the
exclusive jurisdiction of the United States District Court located in the State
of New York and (b) agrees not to assert as a defense or otherwise that its
property is exempt or immune from attachment or execution, that any such action
brought in the above-named court should be dismissed on grounds of forum non
conveniens, should be transferred or removed to any court other than the
above-named court, or should be stayed by reason of the pendency of some other
proceeding in any other court other than the above-named court, or that this
Agreement or the subject matter hereof may not be enforced in or by such court.
12.1.3.    Governing Law. This Agreement shall be construed and the respective
rights of the Parties determined according to the substantive laws of the State
of New York notwithstanding the provisions governing conflict of laws under such
New York law to the contrary.

12.2    Assignment. Except as provided in this Section 12.2, this Agreement may
not be assigned or otherwise transferred, nor may any right or obligation
hereunder be assigned or transferred, by either Party without the consent of the
other Party. Either Party may, however, without the other Party’s consent,
assign this Agreement and its rights and obligations hereunder in whole or in
part to an Affiliate or pursuant to a Change of Control. To the extent that the
assigning Party survives as a legal entity, the assigning Party shall remain
responsible for the performance by its assignee of this Agreement or any
obligations hereunder so assigned to such assignee.

12.3    Amendments. This Agreement and the Schedules referred to in this
Agreement constitute the entire agreement between the Parties with respect to
the subject matter hereof and supersede all previous arrangements with respect
to the subject matter hereof, whether written or oral. Any amendment or
modification to this Agreement shall be made in writing signed by both Parties.

12.4    Notices. Any consent, notice or report required or permitted to be given
or made under this Agreement by one of the Parties hereto to the other shall be
in writing and (a) delivered by hand, (b) sent by nationally recognized
overnight delivery service, (c) sent by registered or certified mail, return
receipt requested, postage prepaid, or (d) sent by facsimile transmission
confirmed by prepaid, registered or certified mail letter, and shall be deemed
to have been properly served to the addressee upon receipt of such written
communication, in any event to the following addresses:

If to Acceleron:
Acceleron Pharma, Inc.

149 Sidney Street

Cambridge, MA 02139

Attn: President

Telephone: (617) 649-9200

Fax: (617) 576-2224

with a copy to:
Ropes & Gray LLP

Prudential Tower

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800 Boylston Street

Boston, MA 02119

Attn: Marc A. Rubenstein

Telephone: (617) 951-7000
Fax: (617) 235-0706

If to Celgene:
[* * *]

Attn: [* * *]
Telephone: [* * *]
Fax: [* * *]

with a copy to:
[* * *]

Attn: [* * *]
Telephone: [* * *]
Fax: [* * *]
Either Party may change its address to which notices shall be sent by giving
notice to the other Party in the manner herein provided.

12.5    Force Majeure. No failure or omission by either Party in the performance
of any obligation of this Agreement shall be deemed a breach of this Agreement
or create any liability if the same shall arise from any cause or causes beyond
the reasonable control of such Party, including the following: acts of god; acts
or omissions of any government; any rules, regulations or orders issued by any
governmental authority or by any officer, department, agency or instrumentality
thereof; fire; storm; flood; earthquake; accident; war; terrorist act;
rebellion; insurrection; riot; and invasion; provided that such Party provides
notice to the other Party of such an event, and the non-performing Party uses
Commercially Reasonable Efforts to cure such failure or omission resulting from
one of the above causes as soon as is practicable; provided further that, in the
event the suspension of performance continues for [* * *] days, and such failure
to perform would constitute a material breach of this Agreement in the absence
of such force majeure event, the Parties will discuss how to proceed under this
Agreement, which may include termination of this Agreement by the non-affected
Party.

12.6    Compliance with Applicable Laws. Neither Party shall export any
technology licensed to it by the other Party under this Agreement except in
compliance with United States export laws and regulations. The Parties shall at
all times comply with all material laws and regulations applicable to its
activities under this Agreement.

12.7    Independent Contractors. It is understood and agreed that the
relationship between the Parties is that of independent contractors and that
nothing in this Agreement shall be construed as authorization for either
Acceleron or Celgene to act as agent for the other. Nothing herein contained
shall be deemed to create an employment, agency, joint venture or partnership
relationship between the Parties or any of their agents or employees for any
purpose, including tax purposes, or to create

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any other legal arrangement that would impose liability upon one Party for the
act or failure to act of the other Party. Neither Party shall have any express
or implied power to enter into any contracts or commitments or to incur any
liabilities in the name of, or on behalf of, the other Party, or to bind the
other Party in any respect whatsoever.

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

12.9    No Strict Construction. This Agreement has been prepared jointly and
shall not be strictly construed against either Party.

12.10    Headings. The captions or headings of the sections or other
subdivisions hereof are inserted only as a matter of convenience or for
reference and shall have no effect on the meaning of the provisions hereof.

12.11    No Implied Waivers; Rights Cumulative. No failure on the part of
Acceleron or Celgene to exercise, and no delay in exercising, any right, power,
remedy or privilege under this Agreement, or provided by statute or at law or in
equity or otherwise, shall impair, prejudice or constitute a waiver of any such
right, power, remedy or privilege or be construed as a waiver of any breach of
this Agreement or as an acquiescence therein, nor shall any single or partial
exercise of any such right, power, remedy or privilege preclude any other or
further exercise thereof or the exercise of any other right, power, remedy or
privilege.

12.12    Effect of Restatement; Entire Agreement. From and after the Amended and
Restated Effective Date, this Agreement (including the Exhibits and Schedules
hereto) constitutes the entire agreement between the Parties with respect to the
subject matter hereof, and supersedes and replaces all prior agreements and
negotiations with respect to such subject matter from and after the Amended and
Restated Effective Date, including the Original Agreement and the Amended
Agreement. The effectiveness of this Agreement shall be without prejudice to the
rights of either Party against the other Party accrued or accruing under the
Amended Agreement prior to the Amended and Restated Effective Date.

12.13    Severability. If any provision hereof should be held invalid, illegal
or unenforceable in any respect in any jurisdiction, the Parties hereto shall
substitute, by mutual consent, valid provisions for such invalid, illegal or
unenforceable provisions, which valid provisions in their economic effect are
sufficiently similar to the invalid, illegal or unenforceable provisions that it
can be reasonably assumed that the Parties would have entered into this
Agreement with such valid provisions. In case such valid provisions cannot be
agreed upon, the invalid, illegal or unenforceable of one or several provisions
of this Agreement shall not affect the validity of this Agreement as a whole,

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unless the invalid, illegal or unenforceable provisions are of such essential
importance to this Agreement that it is to be reasonably assumed that the
Parties would not have entered into this Agreement without the invalid, illegal
or unenforceable provisions.

12.14    No Third Party Beneficiaries. No person or entity other than Celgene,
Acceleron and their respective Affiliates and permitted assignees hereunder
shall be deemed an intended beneficiary hereunder or have any right to enforce
any obligation of this Agreement.

12.15    Execution in Counterparts. This Agreement may be executed in
counterparts, each of which counterparts, when so executed and delivered, shall
be deemed to be an original, and all of which counterparts, taken together,
shall constitute one and the same instrument.

[Signature page follows]

IN WITNESS WHEREOF, the Parties have executed this Collaboration, License and
Option Agreement as of the date first set forth above.
ACCELERON PHARMA, INC.

By: /s/ Habib Dable    
Name: Habib Dable    
Title: President and Chief Executive Officer    

CELGENE CORPORATION

By: /s/ Angus J. Grant    
Name: Angus J. Grant    
Title: Corporate Vice President, Business Development    

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EXHIBIT A
COPY OF THE SALK LICENSE

[Attached to Original Agreement.]

 

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SCHEDULE 1.5

ACCELERON PATENT RIGHTS
Acceleron Dkt. No.

Title
Serial No.
Publication No.
Status
Filing Date
[* * *]

[* * *]

[* * *]
[* * *]
[* * *]
[* * *]

    

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SCHEDULE 1.12

ACTIVIN A/ACTIVIN A ANTIBODY PATENT RIGHTS
[* * *]
[* * *]
[* * *]
[* * *]
[* * *]
[* * *]

    

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SCHEDULE 1.15

ACTIVIN B/ACTIVIN B ANTIBODY PATENT RIGHTS
[* * *]
[* * *]
[* * *]
[* * *]
[* * *]
[* * *]

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SCHEDULE 1.23

BMP-3/BMP-3 ANTIBODY PATENT RIGHTS
Acceleron Dkt. No.

Title
Serial No.
Publication No.
Status
Filing Date
[* * *]
[* * *]
[* * *]
[* * *]
[* * *]
[* * *]

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SCHEDULE 1.109

SOTATERCEPT LICENSED COMPOUND

[* * *]

          

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SCHEDULE 2.8

THIRD PARTY SERVICE PROVIDERS
[* * *]

    
          

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SCHEDULE 4.6.6

OUTSIDE COUNSEL FOR INVENTORSHIP/PATENT DISPUTES
[* * *]

    

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SCHEDULE 6.2.3

DESIGNATED THIRD PARTY ACQUIRORS

[* * *]

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SCHEDULE 8.1

SALK PATENT RIGHTS
Attorney Docket No.

Title
Serial No.

Patent No.
Status
Filing Date
Issue Date
[* * *]
[* * *]
[* * *]
[* * *]
[* * *]
[* * *]
[* * *]

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SCHEDULE 9.3

PRESS RELEASE

exhibit102amendedandr_image1.gif [exhibit102amendedandr_image1.gif]

Acceleron to Develop Sotatercept in Pulmonary Arterial Hypertension

- Acceleron gains rights to fund, develop, and lead global commercialization of,
sotatercept in pulmonary arterial hypertension -

- Acceleron expects to initiate a Phase 2 trial of sotatercept in pulmonary
arterial hypertension in 1H 2018 -

- Preclinical results show potential first-in-class disease modifying properties
of sotatercept in pulmonary arterial hypertension -

- Sotatercept is a well-defined TGF-beta superfamily ligand trap with a widely
established preclinical and clinical profile -

CAMBRIDGE, MA – September 19, 2017 – Acceleron Pharma Inc. (NASDAQ: XLRN), the
leading biopharmaceutical company in the discovery and development of TGF-beta
therapeutics to treat serious and rare diseases, today announced it has amended
the sotatercept development and commercialization collaboration agreement with
Celgene Corporation, originally executed on February 20, 2008. The amended
agreement provides Acceleron with global access to sotatercept for development
and commercialization in pulmonary arterial hypertension (PAH).

“We are very pleased to announce the execution of this amended agreement
alongside our long-time collaboration partner, Celgene. Sotatercept shows
tremendous potential to be a groundbreaking therapy for pulmonary arterial
hypertension, and we expect sotatercept, as a Phase 2-ready compound, to be
Acceleron’s lead molecule as we build our new focus in pulmonary disorders,”
said Habib Dable, Chief Executive Officer for Acceleron. “Our mission with
sotatercept now, as we move to initiate a Phase 2 trial in the first half of
2018, is to improve the lives of those living with pulmonary arterial
hypertension.”

“While many therapies are approved for the treatment of pulmonary arterial
hypertension, these therapies all focus on a mechanism of vasodilation and the
prognosis for patients remains poor,” Eric Austin, M.D., Director, Vanderbilt
Pediatric Pulmonary Hypertension Program. “Sotatercept’s mechanism is intended
to rectify the deficits in molecular signaling that underlie both the familial
and idiopathic forms of this disease. The preclinical data with sotatercept is
very encouraging, and I look forward to seeing data from clinical trials.”
 
“This amended agreement unites Acceleron’s scientific leadership in the TGF-beta
superfamily with Celgene’s commitment to advance novel molecules, such as
sotatercept, for patients in therapeutic areas of high unmet medical need,” said
Scott Smith, Chief Operating Officer for Celgene.

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Under the amended and restated collaboration agreement, Acceleron has the right
to fund and conduct all research and development activities for sotatercept in
the pulmonary hypertension field. Should sotatercept be approved for an
indication in the pulmonary hypertension field, Acceleron will be responsible
for global commercialization and Celgene will be eligible to receive royalties
on global net sales in that field. The original collaboration deal terms will
remain in place with respect to development and commercialization outside of the
pulmonary hypertension field.

Sotatercept is an investigational product that is not approved for use in any
country.

Acceleron R&D Day Conference Call and Webcast Information

The live webcast will be accessible under "Events & Presentations" in the
Investors/Media page of the Company's website at www.acceleronpharma.com.
Individuals can participate in the conference call by dialing
877-312-5848 (domestic) or 253-237-1155 (international) and refer to "Acceleron
2017 R&D Day."
The archived webcast will be available for replay on the Acceleron website
approximately two hours after the event.

About sotatercept

Sotatercept is an activin receptor type IIA fusion protein that acts as a ligand
trap for members in the transforming growth factor-beta (TGF-β) protein
superfamily involved in remodeling and regeneration of a variety of different
tissues, including the vasculature and fibrosis.

About Pulmonary Arterial Hypertension

Pulmonary Arterial Hypertension (PAH) is a rare and chronic, rapidly progressing
disorder characterized by the constriction of small pulmonary arteries
transporting high pressure blood from the heart to the lungs. The high or
increased blood pressure causes significant strain on the heart, often leading
to limited physical activity, heart failure and reduced life expectancy. The
5-year survival rate for patients with PAH is approximately 57%. There are
currently four classes of therapies approved for treatment of PAH: endothelin
receptor antagonists (ERAs), phosphodiesterase-5 (PDE-5) inhibitors,
prostacyclin analogues and soluble guanylate cyclase (sGC) stimulators. The
available therapies all act by promoting the dilation of pulmonary vessels,
which have positive effects for patients, but do not impact the underlying cause
of the disease. As a result, PAH often progresses rapidly for many patients
despite standard of care treatment. A growing body of research has implicated
imbalances in BMP and TGF-β signaling as a primary driver of PAH in familial,
idiopathic and acquired forms of the disease.

About Acceleron

Acceleron is the biopharmaceutical leader in TGF-beta science, focused on the
discovery and development of innovative therapeutics to treat patients with
serious and rare diseases. Its pioneering research and protein engineering
platform engages the target-rich TGF-beta superfamily and its remarkable ability
to regulate cellular growth and repair.

Under a global partnership with Celgene, Acceleron is in Phase 3 development
with luspatercept, a potential first-in-class chronic anemia therapy for the
treatment of rare blood diseases. The Company is also advancing a neuromuscular
franchise with two distinct Myostatin+ agents, ACE-083 and ACE-2494, and a
pulmonary

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program with a Phase 2 trial of sotatercept planned in pulmonary arterial
hypertension. Acceleron has ongoing preclinical research efforts targeting
additional indications in these three disease areas where there is significant
unmet medical need.

For more information, please visit www.acceleronpharma.com. Follow Acceleron on
Social Media: @AcceleronPharma and LinkedIn.

Forward-Looking Statements

This press release contains forward-looking statements about the Company's
strategy, future plans and prospects, including statements regarding the
development of the Company's compounds, the timeline for clinical development
and regulatory approval of the Company’s compounds and the expected timing for
reporting of data from ongoing clinical trials. The words "anticipate,"
"believe," "could," "estimate," "expect," "intend," "may," "plan," "potential,"
"project," "should," "target," "will," "would," and similar expressions are
intended to identify forward-looking statements, although not all
forward-looking statements contain these identifying words.

Actual results could differ materially from those included in the
forward-looking statements due to various risks and uncertainties, including,
but not limited to, that preclinical testing of the Company's compounds and data
from clinical trials may not be predictive of the results or success of ongoing
or later clinical trials, that the development of the Company's compounds will
take longer and/or cost more than planned, that the Company or its collaboration
partner, Celgene, will be unable to successfully complete the clinical
development of the Company’s compounds, that the Company or Celgene may be
delayed in initiating, enrolling or completing any clinical trials, and that the
Company's compounds will not receive regulatory approval or become commercially
successful products. These and other risks and uncertainties are identified
under the heading "Risk Factors" included in the Company's most recent Annual
Report on Form 10-K, and other filings that the Company has made and may make
with the SEC in the future.

The forward-looking statements contained in this press release are based on
management’s current views, plans, estimates, assumptions and projections with
respect to future events, and the Company does not undertake and specifically
disclaims any obligation to update any forward-looking statements.

Contacts:

Acceleron Pharma Inc.
Todd James, IRC, (617) 649-9393
Vice President, Investor Relations and Corporate Communications
Or
Candice Ellis, (617) 649-9226
Manager, Investor Relations and Corporate Communications

Media:
BMC Communications
Brad Miles, (646) 513-3125

Source: Acceleron Pharma
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