EX-10.1



 EXECUTION VERSION 
  

					
		 	 Confidential Materials omitted and filed separately with the

Securities and Exchange Commission. Double asterisks denote omissions.
	 	Exhibit 10.1

 AMENDED AND RESTATED 

COLLABORATION AND LICENSE AGREEMENT 

among 
 CELGENE RIVOT
LTD., 
 CELGENE CORPORATION 

and 
 EPIZYME, INC.








 EXECUTION VERSION 

Table of Contents 
  

							
	 	  	 	  	Page	 
		
	ARTICLE 1 DEFINITIONS	  	 	1	  
			
	 1.1
	  	 “Accounting Principles”
	  	 	1	  
	 1.2
	  	 “Affiliate”
	  	 	2	  
	 1.3
	  	 “Annual Net Sales”
	  	 	2	  
	 1.4
	  	 “Antitrust Laws”
	  	 	2	  
	 1.5
	  	 “Available Target”
	  	 	2	  
	 1.6
	  	 “Business Combination”
	  	 	2	  
	 1.7
	  	 “Business Day”
	  	 	2	  
	 1.8
	  	 “Calendar Quarter”
	  	 	2	  
	 1.9
	  	 “Calendar Year”
	  	 	3	  
	 1.10
	  	 “CELGENE Background IP”
	  	 	3	  
	 1.11
	  	 “CELGENE Collaboration IP”
	  	 	3	  
	 1.12
	  	 “CELGENE Development Candidate”
	  	 	3	  
	 1.13
	  	 “CELGENE Development Program”
	  	 	4	  
	 1.14
	  	 “CELGENE IP”
	  	 	4	  
	 1.15
	  	 “CELGENE Patent(s)”
	  	 	4	  
	 1.16
	  	 “CELGENE Provided Compound”
	  	 	4	  
	 1.17
	  	 “CELGENE Provided Compound IP”
	  	 	4	  
	 1.18
	  	 “CELGENE Provided Compound Patents”
	  	 	4	  
	 1.19
	  	 “CELGENE Territory”
	  	 	4	  
	 1.20
	  	 “cGMP”
	  	 	4	  
	 1.21
	  	 “Chemistry IP”
	  	 	5	  
	 1.22
	  	 “Clinical Trial”
	  	 	5	  
	 1.23
	  	 “CMC”
	  	 	5	  
	 1.24
	  	 “Collaboration IP”
	  	 	5	  
	 1.25
	  	 “Commercialization” and “Commercialize”
	  	 	5	  
	 1.26
	  	 “Commercially Reasonable Efforts”
	  	 	5	  
	 1.27
	  	 “Comparable Third Party Product”
	  	 	6	  
	 1.28
	  	 “Comparable Third Party Product Competition”
	  	 	6	  
	 1.29
	  	 “Compound(s)”
	  	 	6	  
	 1.30
	  	 “Control”, “Controls” or “Controlled”
	  	 	6	  
	 1.31
	  	 “Cover”, “Covering” or “Covered”
	  	 	7	  
	 1.32
	  	 “[**]”
	  	 	7	  
	 1.33
	  	 “Develop” or “Development”
	  	 	7	  
	 1.34
	  	 “Development Candidate”
	  	 	7	  
	 1.35
	  	 “Development Candidate Selection Criteria”
	  	 	7	  
	 1.36
	  	 “Development Costs”
	  	 	7	  
	 1.37
	  	 “Development Plan”
	  	 	7	  
	 1.38
	  	 “Development Program”
	  	 	8	  
	 1.39
	  	 “Development Term”
	  	 	8	  
	 1.40
	  	 “Diagnostic Product”
	  	 	8	  
	 1.41
	  	 “Directed”
	  	 	8	  









							
	 1.42
	  	 “Dollars” or “$”
	  	 	8	  
	 1.43
	  	 “DOT1L”
	  	 	8	  
	 1.44
	  	 “DOT1L Compound(s)”
	  	 	8	  
	 1.45
	  	 “DOT1L Phase 1 Costs”
	  	 	9	  
	 1.46
	  	 “End of Phase 1 Date”
	  	 	9	  
	 1.47
	  	 “EMA”
	  	 	9	  
	 1.48
	  	 “EPIZYME Background Chemistry IP”
	  	 	9	  
	 1.49
	  	 “EPIZYME Background IP”
	  	 	9	  
	 1.50
	  	 “EPIZYME Collaboration IP”
	  	 	9	  
	 1.51
	  	 “EPIZYME IP”
	  	 	10	  
	 1.52
	  	 “EPIZYME Patent(s)”
	  	 	10	  
	 1.53
	  	 “EPIZYME Territory”
	  	 	10	  
	 1.54
	  	 “EPZ5676”
	  	 	10	  
	 1.55
	  	 “EU”
	  	 	10	  
	 1.56
	  	 “Executive Officers”
	  	 	10	  
	 1.57
	  	 “FDA”
	  	 	10	  
	 1.58
	  	 “Field”
	  	 	10	  
	 1.59
	  	 “First Commercial Sale”
	  	 	10	  
	 1.60
	  	 “Global Development Costs”
	  	 	10	  
	 1.61
	  	 “GLP”
	  	 	11	  
	 1.62
	  	 “HSR Act”
	  	 	11	  
	 1.63
	  	 “IND”
	  	 	11	  
	 1.64
	  	 “IND Data Package”
	  	 	11	  
	 1.65
	  	 “IND Milestone Payment”
	  	 	11	  
	 1.66
	  	 “IND Option Period”
	  	 	11	  
	 1.67
	  	 “Indication”
	  	 	11	  
	 1.68
	  	 “Initiation”
	  	 	11	  
	 1.69
	  	 “Joint Collaboration Chemistry IP”
	  	 	11	  
	 1.70
	  	 “Joint Collaboration IP”
	  	 	12	  
	 1.71
	  	 “Joint Collaboration Non-Chemistry IP”
	  	 	12	  
	 1.72
	  	 “Know-How”
	  	 	12	  
	 1.73
	  	 “Lapsed Target”
	  	 	12	  
	 1.74
	  	 “Law” or “Laws”
	  	 	12	  
	 1.75
	  	 “Lead Candidate”
	  	 	12	  
	 1.76
	  	 “Lead Candidate Criteria”
	  	 	13	  
	 1.77
	  	 “Lead Candidate Product”
	  	 	13	  
	 1.78
	  	 “Legal Exclusivity”
	  	 	13	  
	 1.79
	  	 “License Event”
	  	 	13	  
	 1.80
	  	 “Licensed Compound(s)”
	  	 	13	  
	 1.81
	  	 “Licensed Product(s)”
	  	 	14	  
	 1.82
	  	 “LLS”
	  	 	14	  
	 1.83
	  	 “LLS Agreement”
	  	 	14	  
	 1.84
	  	 “MAA”
	  	 	14	  
	 1.85
	  	 “Major EU Country”
	  	 	14	  
	 1.86
	  	 “Manufacture” or “Manufacturing”
	  	 	14	  


  
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	 1.87
	  	 “MHLW”
	  	 	14	  
	 1.88
	  	 “MMRF”
	  	 	14	  
	 1.89
	  	 “MMRF Agreement”
	  	 	14	  
	 1.90
	  	 “NDA”
	  	 	15	  
	 1.91
	  	 “Net Sales”
	  	 	15	  
	 1.92
	  	 “[**]”
	  	 	17	  
	 1.93
	  	 “Option Term”
	  	 	17	  
	 1.94
	  	 “Out-of-Pocket Costs”
	  	 	17	  
	 1.95
	  	 “Patent”
	  	 	17	  
	 1.96
	  	 “Patent-Based Exclusivity”
	  	 	17	  
	 1.97
	  	 “Person”
	  	 	17	  
	 1.98
	  	 “Phase 1 Clinical Trial”
	  	 	17	  
	 1.99
	  	 “Phase 1 Data Package”
	  	 	17	  
	 1.100
	  	 “Phase 1 Option Period”
	  	 	18	  
	 1.101
	  	 “Phase 2 Clinical Trial”
	  	 	18	  
	 1.102
	  	 “Phase 3 Clinical Trial”
	  	 	18	  
	 1.103
	  	 “Pivotal Clinical Trial”
	  	 	18	  
	 1.104
	  	 “Product Liability”
	  	 	18	  
	 1.105
	  	 “Prosecution and Maintenance” or “Prosecute and Maintain”
	  	 	19	  
	 1.106
	  	 “Regulatory Approval”
	  	 	19	  
	 1.107
	  	 “Regulatory Authority”
	  	 	19	  
	 1.108
	  	 “Regulatory-Based Exclusivity”
	  	 	19	  
	 1.109
	  	 “Regulatory Materials”
	  	 	19	  
	 1.110
	  	 “Related Compound”
	  	 	20	  
	 1.111
	  	 “Research Plan”
	  	 	20	  
	 1.112
	  	 “Selection Term”
	  	 	20	  
	 1.113
	  	 “Shared Development Program”
	  	 	20	  
	 1.114
	  	 “Sublicensee”
	  	 	20	  
	 1.115
	  	 “[**]”
	  	 	21	  
	 1.116
	  	 “[**]”
	  	 	21	  
	 1.117
	  	 “Target”
	  	 	21	  
	 1.118
	  	 “Territory-Specific Development Costs”
	  	 	21	  
	 1.119
	  	 “Third Party”
	  	 	21	  
	 1.120
	  	 “UNC”
	  	 	21	  
	 1.121
	  	 “UNC Agreement”
	  	 	21	  
	 1.122
	  	 “United States” or “U.S.”
	  	 	21	  
	 1.123
	  	 “Valid Claim”
	  	 	21	  
	 1.124
	  	 Additional Definitions.
	  	 	22	  
		
	 ARTICLE 2 AMENDMENT AND RESTATEMENT; COLLABORATION; RESEARCH PLAN; OPT-OUTS
	  	 	25	  
			
	 2.1
	  	 Amendment and Restatement.
	  	 	25	  
	 2.2
	  	 Collaboration Overview.
	  	 	26	  
	 2.3
	  	 Research Plan; Research Activities.
	  	 	26	  


  
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	 2.4
	  	 EPIZYME Pre-IND Opt-Out.
	  	 	29	  
	 2.5
	  	 EPIZYME Post-EOP1 Clinical Opt-Out.
	  	 	33	  
	 2.6
	  	 EPIZYME Late Stage Opt-Out.
	  	 	34	  
	 2.7
	  	 Data Transfer; HSR Approval.
	  	 	41	  
	 2.8
	  	 IND and Phase 1 Development.
	  	 	42	  
	 2.9
	  	 Options; Target Selection.
	  	 	44	  
	 2.10
	  	 Reports; Results.
	  	 	46	  
	 2.11
	  	 Subcontracting.
	  	 	46	  
	 2.12
	  	 Regulatory Matters; Compliance.
	  	 	47	  
		
	 ARTICLE 3 DEVELOPMENT AND COMMERCIALIZATION
	  	 	53	  
			
	 3.1
	  	 Development Plans.
	  	 	53	  
	 3.2
	  	 Development Activities.
	  	 	54	  
	 3.3
	  	 Reports.
	  	 	56	  
	 3.4
	  	 Commercialization.
	  	 	56	  
	 3.5
	  	 Diligence.
	  	 	57	  
	 3.6
	  	 No Representation.
	  	 	57	  
		
	 ARTICLE 4 GOVERNANCE
	  	 	58	  
			
	 4.1
	  	 Joint Research Committee.
	  	 	58	  
	 4.2
	  	 Joint Development Committee.
	  	 	60	  
	 4.3
	  	 Joint Commercialization Committee.
	  	 	62	  
	 4.4
	  	 Procedures of the JRC, JDC and JCC.
	  	 	63	  
	 4.5
	  	 Patent Committee.
	  	 	66	  
	 4.6
	  	 Alliance Managers.
	  	 	69	  
	 4.7
	  	 Assigned Activities.
	  	 	69	  
		
	 ARTICLE 5 LICENSE GRANTS
	  	 	69	  
			
	 5.1
	  	 License Grants To CELGENE.
	  	 	69	  
	 5.2
	  	 License Grants to EPIZYME.
	  	 	72	  
	 5.3
	  	 Licenses to CELGENE Lead Candidates.
	  	 	74	  
	 5.4
	  	 Rights Retained by the Parties.
	  	 	75	  
	 5.5
	  	 Section 365(n) of the Bankruptcy Code.
	  	 	75	  
	 5.6
	  	 Technical Transfer and Disclosure of Know-How.
	  	 	76	  
		
	 ARTICLE 6 FINANCIAL TERMS
	  	 	76	  
			
	 6.1
	  	 Amendment Fee.
	  	 	76	  
	 6.2
	  	 Research Funding During the Selection Term.
	  	 	76	  
	 6.3
	  	 Development Funding.
	  	 	76	  
	 6.4
	  	 Territory-Specific Development Costs.
	  	 	77	  
	 6.5
	  	 Milestones.
	  	 	78	  
	 6.6
	  	 Royalties.
	  	 	82	  


  
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	 6.7
	  	 Reports; Royalty Payments.
	  	 	87	  
	 6.8
	  	 Methods of Payments; Payments Non-Refundable and Non-Creditable.
	  	 	87	  
	 6.9
	  	 Accounting.
	  	 	87	  
	 6.10
	  	 Taxes.
	  	 	88	  
	 6.11
	  	 Late Payments.
	  	 	89	  
	 6.12
	  	 Diagnostic Products.
	  	 	89	  
		
	 ARTICLE 7 EXCLUSIVITY
	  	 	89	  
			
	 7.1
	  	 Target Exclusivity.
	  	 	89	  
		
	 ARTICLE 8 OWNERSHIP OF INTELLECTUAL PROPERTY RIGHTS
	  	 	92	  
			
	 8.1
	  	 Ownership.
	  	 	92	  
	 8.2
	  	 Prosecution and Maintenance of Patents.
	  	 	93	  
	 8.3
	  	 Patent Costs.
	  	 	95	  
	 8.4
	  	 Defense of Claims Brought by Third Parties.
	  	 	95	  
	 8.5
	  	 Enforcement of EPIZYME Patents and CELGENE Patents.
	  	 	96	  
	 8.6
	  	 Regulatory Data Protection.
	  	 	97	  
	 8.7
	  	 Patent Term Extensions.
	  	 	98	  
	 8.8
	  	 Common Interest Disclosures.
	  	 	99	  
		
	 ARTICLE 9 CONFIDENTIALITY
	  	 	99	  
			
	 9.1
	  	 Confidentiality; Exceptions.
	  	 	99	  
	 9.2
	  	 Authorized Disclosure.
	  	 	100	  
	 9.3
	  	 Press Release; Disclosure of Agreement.
	  	 	102	  
	 9.4
	  	 Remedies.
	  	 	104	  
	 9.5
	  	 Publications.
	  	 	104	  
	 9.6
	  	 Clinical Trial Register.
	  	 	106	  
		
	 ARTICLE 10 REPRESENTATIONS AND WARRANTIES
	  	 	106	  
			
	 10.1
	  	 Representations and Warranties of Both Parties.
	  	 	106	  
	 10.2
	  	 Representations and Warranties of EPIZYME.
	  	 	107	  
	 10.3
	  	 Representations and Warranties of CELGENE.
	  	 	109	  
	 10.4
	  	 Mutual Covenants.
	  	 	110	  
	 10.5
	  	 Disclaimer.
	  	 	110	  
		
	 ARTICLE 11 INDEMNIFICATION; INSURANCE
	  	 	111	  
			
	 11.1
	  	 Indemnification by CELGENE.
	  	 	111	  
	 11.2
	  	 Indemnification by EPIZYME.
	  	 	112	  
	 11.3
	  	 Procedure and Conditions to Indemnification.
	  	 	112	  
	 11.4
	  	 Insurance.
	  	 	114	  
	 11.5
	  	 LIMITATION OF LIABILITY.
	  	 	115	  


  
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	 ARTICLE 12 TERM AND TERMINATION
	  	 	115	  
			
	 12.1
	  	 Term; Expiration.
	  	 	115	  
	 12.2
	  	 Unilateral Termination by CELGENE.
	  	 	117	  
	 12.3
	  	 Termination for Cause.
	  	 	117	  
	 12.4
	  	 Termination for Patent Challenges.
	  	 	120	  
	 12.5
	  	 Termination for Bankruptcy.
	  	 	121	  
	 12.6
	  	 Effects of Termination.
	  	 	122	  
	 12.7
	  	 Accrued Rights; Surviving Provisions; Right to Set-off.
	  	 	128	  
		
	 ARTICLE 13 MISCELLANEOUS
	  	 	128	  
			
	 13.1
	  	 Dispute Resolution.
	  	 	128	  
	 13.2
	  	 Baseball Arbitration.
	  	 	129	  
	 13.3
	  	 Venue; Jurisdiction.
	  	 	130	  
	 13.4
	  	 Governing Law.
	  	 	130	  
	 13.5
	  	 Assignment.
	  	 	130	  
	 13.6
	  	 Performance Warranty.
	  	 	131	  
	 13.7
	  	 Force Majeure.
	  	 	131	  
	 13.8
	  	 Notices.
	  	 	131	  
	 13.9
	  	 Export Clause.
	  	 	133	  
	 13.10
	  	 Waiver.
	  	 	133	  
	 13.11
	  	 Severability.
	  	 	133	  
	 13.12
	  	 Entire Agreement.
	  	 	133	  
	 13.13
	  	 Independent Contractors.
	  	 	134	  
	 13.14
	  	 Non-solicitation of Key Employees.
	  	 	134	  
	 13.15
	  	 Headings; Construction; Interpretation.
	  	 	134	  
	 13.16
	  	 Books and Records.
	  	 	135	  
	 13.17
	  	 Further Actions.
	  	 	135	  
	 13.18
	  	 Parties in Interest.
	  	 	135	  
	 13.19
	  	 Performance by Affiliates.
	  	 	135	  
	 13.20
	  	 Counterparts.
	  	 	135	  
	 13.21
	  	 PARENT Guarantee.
	  	 	135	  

 List of Exhibits 
  

					
	Exhibit A	  	-	  	Initial Research Plan
	Exhibit B	  	-	  	Form of CELGENE Provided Compound Transfer Agreement
	Exhibit C	  	-	  	Press Release
	Exhibit D	  	-	  	Redacted Version of the Agreement for Disclosure to Investors, Lenders, Acquirors and Merger Partners
	Exhibit E	  	-	  	Redacted Version of the Agreement for Disclosure to Potential Licensees, Sublicensees and Collaborators


  
 - vi - 








 List of Schedules 
  

					
	Schedule 1.35	  	-	  	Development Candidate Selection Criteria
	Schedule 1.76	  	-	  	Lead Candidate Criteria
	Schedule 1.92	  	-	  	[**]
	Schedule 1.115	  	-	  	[**]
	Schedule 1.116	  	-	  	[**]
	Schedule 10.2(a)	  	-	  	EPIZYME Patents
	Schedule 10.2(b)	  	-	  	EPIZYME Agreements
	Schedule 13.14	  	-	  	Key Employees


  
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 EXECUTION VERSION 

AMENDED AND RESTATED 

COLLABORATION AND LICENSE AGREEMENT 

This AMENDED AND RESTATED COLLABORATION AND LICENSE AGREEMENT (the “Agreement”) is entered into and made effective as of the
8th day of July, 2015 (the “Effective Date”) among Epizyme, Inc., a Delaware corporation having its principal place of business at 400 Technology Square, 4th Floor, Cambridge, Massachusetts 02139, U.S.A. (“EPIZYME”), Celgene RIVOT Ltd., having its principal place of business at Clarendon House, 2 Church Street Hamilton, HM 11 Bermuda
(“CELGENE”), and, solely for the purposes set forth in Section 13.21, Celgene Corporation, a Delaware corporation having its principal place of business at 86 Morris Avenue, Summit, New Jersey 07901 (“PARENT”).
EPIZYME and CELGENE are each referred to herein by name or as a “Party” or, collectively, as the “Parties.” 

RECITALS 
 WHEREAS,
EPIZYME and Celgene International Sàrl entered into that certain Collaboration and License Agreement, dated April 2, 2012 (the “Original Agreement”) pursuant to which (i) the Parties agreed to engage in a
collaborative effort to carry out research activities directed to novel, small molecule histone methyltransferase (“HMT”) inhibitors and (ii) CELGENE obtained an option to obtain exclusive rights from EPIZYME to develop and
commercialize such inhibitors in the CELGENE Territory (as defined below) directed to Targets (as defined below); 
 WHEREAS, on or about
July 2014, Celgene International Sàrl assigned its rights and interests under the Original Agreement to Celgene RIVOT Ltd.; 

WHEREAS, under the Original Agreement, CELGENE was deemed to have exercised such option with respect to DOT1L (as defined below) as of the
effective date of the Original Agreement; and 
 WHEREAS, the Parties wish to amend and restate the Original Agreement in order to focus
their research and development efforts on the Available Targets (as defined below) and DOT1L, with the goal of identifying and Developing Compounds (as defined below) Directed to such Available Targets and DOT1L. 

NOW, THEREFORE, in consideration of the premises and mutual covenants herein contained, and for other good and valuable consideration, the
receipt and sufficiency of which are hereby acknowledged, the Parties hereby agree as follows: 
 ARTICLE 1 

DEFINITIONS 
 As used in
this Agreement, the following terms will have the meanings set forth in this Article 1 unless the context dictates otherwise: 
 1.1
“Accounting Principles” means either U.S. generally accepted accounting principles (“GAAP”) or International Financial Reporting Standards (“IFRS”), as designated and used by the applicable Party.








 1.2 “Affiliate” means any Person which, directly or indirectly through one or
more intermediaries, controls, is controlled by or is under common control with a Party to this Agreement, for so long as such control exists, whether such Person is or becomes an Affiliate on or after the Effective Date. A Person shall be deemed to
“control” another Person if it: (a) with respect to such other Person that is a corporation, owns, directly or indirectly, beneficially or legally, at least fifty percent (50%) of the outstanding voting securities or capital
stock (or such lesser percentage which is the maximum allowed to be owned by such Person in a particular jurisdiction) of such other Person, or, with respect to such other Person that is not a corporation, has other comparable ownership interest; or
(b) has the power, whether pursuant to contract, ownership of securities or otherwise, to direct the management and policies of such other Person. 

1.3 “Annual Net Sales” means with respect to any Licensed Product or any Lead Candidate Product, total Net Sales by CELGENE,
its Affiliates and Sublicensees in the CELGENE Territory and/or the United States, as applicable, of such Licensed Product or Lead Candidate Product in a particular Calendar Year. 

1.4 “Antitrust Laws” means any Laws designed to prohibit, restrict or regulate actions for the purpose or effect of
monopolization or restraint of trade, including the HSR Act. 
 1.5 “Available Target” means [**], [**] and [**], for so
long as such Targets do not become Lapsed Targets or Selected Targets. For the avoidance of doubt, DOT1L is deemed to be a Selected Target as of the Effective Date. 

1.6 “Business Combination” means with respect to a Party, any of the following events: (a) any Third Party (or group of
Third Parties acting in concert) acquires, directly or indirectly, shares of such Party representing fifty percent (50%) or more of the voting shares (where voting refers to being entitled to vote for the election of directors) then outstanding
of such Party; (b) such Party consolidates with or merges into another corporation or entity which is a Third Party, or any corporation or entity which is a Third Party consolidates with or merges into such Party, in either event pursuant to a
transaction in which more than fifty percent (50%) of the voting shares of the acquiring or resulting entity outstanding immediately after such consolidation or merger is not held by the holders of the outstanding voting shares of such Party
immediately preceding such consolidation or merger; or (c) such Party conveys, transfers or leases all or substantially all of its assets to a Third Party. 

1.7 “Business Day” means a day on which banking institutions in Boston, Massachusetts, United States and New, York, New York,
United States are open for business, excluding any Saturday or Sunday. 
 1.8 “Calendar Quarter” means the period beginning
on the Effective Date and ending on the last day of the calendar quarter in which the Effective Date falls, and thereafter each successive period of three (3) consecutive calendar months ending on the last day of March,


  
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June, September, or December, respectively; provided that, the final Calendar Quarter shall end on the last day of the Term or, in the event an applicable Royalty Term extends
beyond the last day of the Term pursuant to Section 12.6, the last day of such Royalty Term. 
 1.9 “Calendar Year”
means the period beginning on the Effective Date and ending on December 31 of the calendar year in which the Effective Date falls, and thereafter each successive period of twelve (12) consecutive months beginning on January 1 and
ending on December 31; provided that, the final Calendar Year shall end on the last day of the Term or, in the event an applicable Royalty Term extends beyond the last day of the Term pursuant to Section 12.6, the last day of
such Royalty Term. 
 1.10 “CELGENE Background IP” means, collectively: 

(a) “CELGENE Background Know-How,” which means Know-How that (i) is Controlled by CELGENE or any of its Affiliates as
of the Effective Date or thereafter during the Term, (ii) arises outside of the Collaboration, (iii) is provided by CELGENE to the Collaboration for the Parties’ research, Development, Manufacture or Commercialization of Compounds
(including Licensed Compounds), Licensed Products or Diagnostic Products and (iv) is necessary for the research, Development, Manufacture or Commercialization of Compounds (including Licensed Compounds), Licensed Products and Diagnostic
Products in the Field; excluding any and all Know-How that is Chemistry IP; and 
 (b) “CELGENE Background Patents,” which
means Patents Controlled by CELGENE or any of its Affiliates as of the Effective Date or thereafter during the Term that Cover CELGENE Background Know-How; excluding any and all Chemistry IP. 

1.11 “CELGENE Collaboration IP” means, collectively: 

(a) “CELGENE Collaboration Know-How,” which means the Collaboration Know-How Controlled by CELGENE or any of its Affiliates,
except CELGENE’s interest in Joint Collaboration Know-How; and 
 (b) “CELGENE Collaboration Patents,” which means
the Collaboration Patents Controlled by CELGENE or any of its Affiliates, except CELGENE’s interest in Joint Collaboration Patents. 

1.12 “CELGENE Development Candidate” means a Compound that (a) is based upon or derived from any CELGENE Provided
Compound, (b) is identified, synthesized or discovered during the conduct of activities set forth in the Research Plan or applicable Development Plan directed towards the applicable Available Target or Selected Target, as applicable, and
(c) satisfies the applicable Development Candidate Selection Criteria or is deemed to be a Development Candidate pursuant to Section 2.3.5 prior to or upon expiration of the Option Term, or is thereafter deemed to be a CELGENE Development
Candidate pursuant to Section 5.3. 

  
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 1.13 “CELGENE Development Program” means (a) for [**] or [**], the
activities performed or to be performed by CELGENE, its Affiliates and Sublicensees under the applicable Development Plan, to Develop Licensed Compounds and Licensed Products Directed to such Target after such Target becomes a Selected Target, and
related Diagnostic Products, in the Field during the applicable Development Term, (b) the activities performed or to be performed by CELGENE, its Affiliates and Sublicensees to Develop Licensed Compounds and Licensed Products Directed to an
Available Target that becomes a Selected Target pursuant to Sections 2.4 or 2.5, or (c) a Shared Development Program as to which EPIZYME exercises an EPIZYME Post-EOP1 Clinical Opt-Out pursuant to Section 2.5 or an EPIZYME Late Stage
Opt-Out pursuant to Section 2.6. 
 1.14 “CELGENE IP” means CELGENE Background IP, CELGENE Collaboration IP and
CELGENE Provided Compound IP. 
 1.15 “CELGENE Patent(s)” means CELGENE Background Patents, CELGENE Collaboration Patents
and CELGENE Provided Compound Patents. 
 1.16 “CELGENE Provided Compound” means a Compound that (a) is Controlled by
CELGENE or any of its Affiliates as of the Effective Date or thereafter during the Term, (b) arises outside of the Collaboration, and (c) is introduced into the Collaboration in accordance with Section 2.3.2(a)(iii). 

1.17 “CELGENE Provided Compound IP” means (a) Chemistry IP that is Controlled by CELGENE or any of its Affiliates as of
the Effective Date or thereafter during the Term that directly relates to or Covers the chemical structure, composition of matter, Manufacture or use of (i) a CELGENE Provided Compound that is provided to the Collaboration by CELGENE pursuant
to Section 2.3.2(a)(iii) and which is actually used in the Collaboration or (ii) any CELGENE Development Candidate, and (b) Chemistry IP that is assigned to CELGENE pursuant to Section 8.1.3(b). 

1.18 “CELGENE Provided Compound Patents” means Patents Controlled by CELGENE or any of its Affiliates as of the Effective
Date or thereafter during the Term that are within the CELGENE Provided Compound IP. 
 1.19 “CELGENE Territory” means, on
a Selected Target-by-Selected Target basis, (a) with respect to [**] and DOT1L, the entire world except the United States and any Terminated Countries and, if EPIZYME exercises the EPIZYME Pre-IND Opt-Out pursuant to Section 2.4, the
EPIZYME Post-EOP1 Clinical Opt-Out pursuant to Section 2.5 or the EPIZYME Late Stage Opt-Out pursuant to Section 2.6, as of the applicable opt-out date, including the United States and any Terminated Countries, and (b) with respect to
[**] and [**], the entire world except any Terminated Countries. 
 1.20 “cGMP” means all applicable standards relating to
manufacturing practices for fine chemicals, intermediates, bulk products and/or finished pharmaceutical products, including (a) all applicable requirements detailed in the FDA’s current Good Manufacturing Practices regulations, 21 CFR
Parts 210 and 211 and The Rules Governing Medicinal Products in the 

  
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European Community, Volume IV, Good Manufacturing Practice for Medicinal Products, as each may be amended from time to time, and (b) all applicable Laws promulgated by any governmental
authority having jurisdiction over the Manufacture of a Compound, Licensed Compound or Licensed Product, as applicable. 
 1.21
“Chemistry IP” means Know-How that directly relates to, and any Patents that Cover, the chemical structure, composition-of-matter, Manufacture or use of a Compound that (a) (i) is in a Party’s or any of its
Affiliates’ possession as of the Effective Date or comes into the possession of a Party or any of its Affiliates outside of the Collaboration during the Term and (ii) is made available by such Party for use in the Collaboration, or
(b) is identified, synthesized or otherwise discovered in the conduct of the Collaboration. 
 1.22 “Clinical Trial”
means a human clinical trial, including any Phase 1 Clinical Trial, Phase 2 Clinical Trial, Phase 3 Clinical Trial, study incorporating more than one of these phases, Pivotal Clinical Trial, or post-Regulatory Approval clinical trial. 

1.23 “CMC” means the chemistry, manufacturing and controls section of an IND or NDA in the United States, or the equivalent
section of regulatory filings made outside the United States. 
 1.24 “Collaboration IP” means, collectively: 

(a) “Collaboration Know-How,” which means Know-How that is discovered, developed, invented, conceived or reduced to practice
by or on behalf of either Party or its respective Affiliates or Sublicensees, but not both Parties, pursuant to the conduct of activities under the Collaboration or in the exercise of each Party’s licenses under this Agreement, and that is not
assigned to EPIZYME pursuant to Section 8.1.3(a) or to CELGENE pursuant to Section 8.1.3(b); and 
 (b) “Collaboration
Patents,” which means any Patents that Cover any Collaboration Know-How. 
 For purposes of clarity, Collaboration IP does not include either
Party’s interest in Joint Collaboration IP. 
 1.25 “Commercialization” and “Commercialize” means all
activities undertaken relating to the marketing, promotion (including advertising, detailing, sample distribution and sponsored product events), medical education, and any other offering for sale, distribution and sale of a product. 

1.26 “Commercially Reasonable Efforts” means with respect to EPIZYME or CELGENE, as applicable, such efforts that are
consistent with the efforts and resources then used by EPIZYME or PARENT, as applicable, in the exercise of its commercially reasonable practices relating to the research, Development (including seeking Regulatory Approval), Manufacture and
Commercialization of a pharmaceutical product at a similar stage in its research, Development or commercial product life as the relevant Compound (including 

  
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Licensed Compound) or Licensed Product, and that has commercial and market potential similar to the relevant Compound (including Licensed Compound) or Licensed Product, taking into account issues
of intellectual property scope, subject matter and coverage, safety and efficacy, product profile, competitiveness of the marketplace, proprietary position, regulatory exclusivity, anticipated or approved labeling, present and future market
potential, and profitability (including pricing and reimbursement status achieved or likely to be achieved). 
 1.27 “Comparable
Third Party Product” means, with respect to a Licensed Product in any country, any pharmaceutical product sold by a Third Party not authorized by or on behalf of CELGENE, its Affiliates or Sublicensees, that: 

(a) contains, as an active pharmaceutical ingredient, the same Licensed Compound contained in the applicable Licensed Product; and 

(b) is approved by the applicable Regulatory Authority in such country for one or more of the same Indications as the applicable Licensed
Product. 
 A pharmaceutical product that is AB-rated or comparably rated in any jurisdiction outside the United States to the applicable Licensed Product
shall be a Comparable Third Party Product with respect to such Licensed Product. 
 1.28 “Comparable Third Party Product
Competition” means, with respect to a Licensed Product in any country in a given Calendar Quarter, that, during such Calendar Quarter: 

(a) one or more Comparable Third Party Product(s) is commercially available in such country; and 

(b) such Comparable Third Party Product(s) has a market share of: 

(i) [**] percent ([**]%) to less than [**] percent ([**]%), or 

(ii) [**] percent ([**]%) or more, 
 in each
case, of the aggregate market in such country of such Licensed Product and the Comparable Third Party Product(s) (based on sales of units of such Licensed Product and such Comparable Third Party Product(s), as reported by IMS International, or if
such data are not available, such other reliable data source as reasonably agreed by the Parties). 
 1.29 “Compound(s)”
means, with respect to a Target, a small molecule synthesized and used for the purpose of inhibiting or modulating the activity of such Target in any context, and that has the ability to either inhibit or modulate the activity of such Target by at
least [**]percent ([**]%) at [**]. 
 1.30 “Control”, “Controls” or “Controlled” means,
subject to Section 13.5, with respect to any intellectual property, possession of the right (whether through ownership or license (other than a license granted in this Agreement)) to grant the licenses or sublicenses as provided herein without
violating the terms of any then-existing agreement with any Third Party 

  
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and (subject to the immediately succeeding sentence) creating or increasing any payment obligation to a Third Party, including any royalty or milestone payment (the “Additional
Payments”). Notwithstanding the foregoing, if on or after the Effective Date and for such time as the other Party agrees to pay and does in fact pay all Additional Payments, including as set forth in Section 6.6.4, with respect to such
Party’s use of or license to such intellectual property, such intellectual property shall be deemed to be included in the definition of “Control”. 

1.31 “Cover”, “Covering” or “Covered” means, with respect to a product, composition,
technology, process or method that, in the absence of ownership of or a license granted under a Valid Claim, the Manufacture, use, offer for sale, sale or importation of such product or composition, or the practice of such technology, process or
method, would infringe such Valid Claim (or, in the case of a Valid Claim that has not yet issued, would infringe such Valid Claim if it were to issue). 

1.32 [**]. 
 1.33
“Develop” or “Development” means all activities relating to non-clinical and preclinical testing and trials, clinical testing and trials, including Clinical Trials, toxicology testing, modification, optimization and
animal efficacy testing of pharmaceutical compounds, statistical analysis, publication and presentation of study results and reporting, preparation and submission to Regulatory Authorities of applications (including any CMC information) relating to
Compounds (including Licensed Compounds), Licensed Products and Diagnostic Products, and Targets (including Available Targets, Selected Targets, Terminated Targets and Lapsed Targets, as applicable) and obtaining and maintaining Regulatory Approval
thereof. 
 1.34 “Development Candidate” means with respect to a particular Available Target or Selected Target, as
applicable, a Compound Directed to such Target that is designated by the JRC pursuant to Section 2.3.5 as meeting the applicable Development Candidate Selection Criteria, or is otherwise designated a Development Candidate pursuant to
Section 2.3.5, or is a CELGENE Development Candidate in accordance with Section 1.12 or pursuant to Section 5.3. 
 1.35
“Development Candidate Selection Criteria” means the criteria set forth on Schedule 1.35, as such criteria may be amended from time to time upon mutual agreement of the Parties. 

1.36 “Development Costs” means on a Shared Development Program-by-Shared Development Program basis, with respect to
Development activities performed under the applicable Development Plan and pursuant to the approved budget therefor, by or on behalf of a Party hereunder, Out-of-Pocket Costs of the Parties that are specifically associated with the conduct of such
activities during the applicable Development Term, including Out-of-Pocket Costs incurred in establishing, holding and maintaining the global safety database for Licensed Compounds and Licensed Products in the Field in accordance with
Section 2.12.4. 
 1.37 “Development Plan” means, with respect to each Development Program, a research and Development
plan governing the activities to be conducted by the Parties (with respect to DOT1L or [**]) or by CELGENE (with respect to [**] or [**]) during the 

  
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Development Term directed to the applicable Selected Target, with the goal of identifying and developing Licensed Compounds Directed to such Selected Target to achieve Regulatory Approval, as
well as Licensed Compounds that may be suitable as substitutes, backups or replacements for the Development Candidate against the applicable Selected Target. 

1.38 “Development Program” means either a Shared Development Program or a CELGENE Development Program, as the context
requires. 
 1.39 “Development Term” means, subject to early termination with respect to any Development Program or
exercise by EPIZYME of an EPIZYME Post-EOP1 Clinical Opt-Out pursuant to Section 2.5 or an EPIZYME Late Stage Opt-Out pursuant to Section 2.6 with respect to a Shared Development Program, on a Development Program-by-Development Program
basis, the period commencing upon CELGENE’s exercise of the Phase 1 Option with respect to the applicable Selected Target (unless such exercise is prior to the End of Phase 1 Date with respect to a Compound Directed to the applicable Selected
Target, in which case commencing upon the End of Phase 1 Date with respect to such Selected Target), and ending on the date when all Regulatory Approvals have been granted by both the FDA and EMA for all Licensed Compounds and Licensed Products for
all Indications in such Development Program, in each case, for which the JDC, in the case of DOT1L and [**], and CELGENE, in the case of [**] and [**], has determined to pursue Regulatory Approval, provided that, with respect to the
Development Program for DOT1L, the Parties agree that the Development Term commenced prior to the Effective Date under the Original Agreement and continues under this Agreement and, with respect to Development Programs for Available Targets that
become Selected Targets pursuant to Section 2.4 or Section 2.5, the Development Term shall commence upon such Available Targets becoming Selected Targets. 

1.40 “Diagnostic Product” means any biomarker or diagnostic assay or test that is designed for use with, or that relates to,
or is associated with or is correlated with patient populations that do or do not respond to treatment with the applicable Licensed Product or pharmaceutical product comprising a Compound, whether or not as the sole active ingredient and in any
dosage form or formulation, as applicable. 
 1.41 “Directed” means, with respect to a Compound (including a Licensed
Compound) or Licensed Product or Terminated Product, synthesized and used for the purposes of inhibiting or modulating the activity of the applicable Target in any context. 

1.42 “Dollars” or “$” means the legal tender of the U.S. 

1.43 “DOT1L” means DOT1L, exemplified in Okada et al. (2005) hDOT1L links histone methylation to leukemogenesis. Cell
(121):167-178. 
 1.44 “DOT1L Compound(s)” means any Licensed Compound Directed to DOT1L, including EPZ5676. 

  
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 1.45 “DOT1L Phase 1 Costs” means all Development Costs associated with
activities directed to the Development of EPZ5676 through the completion of [**] of EPZ5676 and incurred in accordance with the applicable budget approved by the JDC. 

1.46 “End of Phase 1 Date” means, with respect to an Available Target, the date that is forty-five (45) days after the
delivery by EPIZYME to CELGENE of a complete Phase 1 Data Package for a Development Candidate directed to such Available Target, as such date may be extended pursuant to Section 2.8.4. 

1.47 “EMA” means the European Medicines Agency, and any successor entity thereto. 

1.48 “EPIZYME Background Chemistry IP” means (a) Chemistry IP that (i) is Controlled by EPIZYME or any of its
Affiliates as of the Effective Date or thereafter during the Term, (ii) arises outside of the Collaboration and (iii) is provided by EPIZYME to the Collaboration for the Parties’ research, Development, Manufacture or Commercialization
of Compounds (including Licensed Compounds), Licensed Products or Diagnostic Products, and (b) Chemistry IP that is assigned to EPIZYME pursuant to Section 8.1.3(a). 

1.49 “EPIZYME Background IP” means, collectively: 

(a) “EPIZYME Background Know-How,” which means Know-How that (i) is Controlled by EPIZYME or any of its Affiliates as
of the Effective Date or thereafter during the Term, (ii) arises outside of the Collaboration, (iii) is provided by EPIZYME to the Collaboration for the Parties’ research, Development, Manufacture or Commercialization of Compounds
(including Licensed Compounds), Licensed Products or Diagnostic Products and (iv) is necessary for the research, Development, Manufacture or Commercialization of Compounds (including Licensed Compounds), Licensed Products and Diagnostic
Products in the Field; and 
 (b) “EPIZYME Background Patents,” which means Patents Controlled by EPIZYME or any of its
Affiliates as of the Effective Date or thereafter during the Term that Cover EPIZYME Background Know-How. 
 For the avoidance of doubt, EPIZYME Background
Chemistry IP under Section 1.48(a) constitutes EPIZYME Background IP. 
 1.50 “EPIZYME Collaboration IP” means,
collectively: 
 (a) “EPIZYME Collaboration Know-How,” which means the Collaboration Know-How Controlled by EPIZYME or any
of its Affiliates, except EPIZYME’s interest in Joint Collaboration Know-How; and 
 (b) “EPIZYME Collaboration
Patents,” which means Collaboration Patents Controlled by EPIZYME or any of its Affiliates, except EPIZYME’s interest in Joint Collaboration Patents. 

  
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 1.51 “EPIZYME IP” means EPIZYME Background IP and EPIZYME Collaboration IP. 

1.52 “EPIZYME Patent(s)” means EPIZYME Background Patents and EPIZYME Collaboration Patents. 

1.53 “EPIZYME Territory” means, on a Selected Target-by-Selected Target basis, the entire world except the CELGENE Territory.

 1.54 “EPZ5676” means the DOT1L Compound known as EPZ5676, which is the Development Candidate Directed to DOT1L as of the
Effective Date. 
 1.55 “EU” means all countries that are officially recognized as member states of the European Union at
any particular time during the Term. 
 1.56 “Executive Officers” means EPIZYME’s Chief Executive Officer and
PARENT’s President, Global Research & Early Development (for intellectual property matters, including for purposes of Section 4.5) or PARENT’s Chief Executive Officer (for all other matters) (or their respective designees).

 1.57 “FDA” means the U.S. Food and Drug Administration, and any successor entity thereto. 

1.58 “Field” means any use or purpose, including the treatment, palliation, diagnosis or prevention of any human or animal
disease, disorder or condition. 
 1.59 “First Commercial Sale” means with respect to each Licensed Product, the first sale
for which revenue has been recognized by CELGENE or its Affiliates or Sublicensees for use or consumption by the general public of such Licensed Product in any country in the CELGENE Territory for which all Regulatory Approvals and pricing or
reimbursement approvals that are legally required in order to sell such Licensed Product in such country have been granted; in each case provided however that the following shall not constitute a First Commercial Sale: 

(a) any sale to an Affiliate or Sublicensee unless the Affiliate or Sublicensee is the last entity in the distribution chain of the Licensed
Product; 
 (b) any use of such Licensed Product in Clinical Trials (including post-Regulatory Approval clinical trials), non-clinical
Development activities or other Development activities with respect to such Licensed Product by or on behalf of a Party, or disposal or transfer of Licensed Products for a bona fide charitable purpose; and 

(c) compassionate use. 
 1.60
“Global Development Costs” means all Development Costs incurred by the Parties with respect to a Shared Development Program in accordance with the applicable budget approved by the JDC, other than the Territory-Specific Development
Costs. 

  
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 1.61 “GLP” means the then-current good laboratory practice standards promulgated
or endorsed by the FDA, as defined in U.S. 21 C.F.R. Part 58 (or such other comparable regulatory standards in jurisdictions outside the U.S. to the extent applicable to the relevant toxicology study, as they may be updated from time to time). 

1.62 “HSR Act” means the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended. 

1.63 “IND” means an investigational new drug application (including any amendment or supplement thereto) submitted to the FDA
pursuant to Part 312 of Title 21 of the U.S. Code of Federal Regulations, including any amendments thereto. References herein to IND shall include, to the extent applicable, any comparable filing(s) outside the U.S. for the investigation of any
product in any other country or group of countries (such as a Clinical Trial Application (“CTA”) in the EU). 
 1.64
“IND Data Package” means, with respect to a Compound directed to an Available Target for which EPIZYME proposes to file an IND in the United States or a Major EU Country and conduct a Phase 1 Clinical Trial, the following:
(i) a reasonably detailed summary of any research and development activities conducted with respect to such Compound, including any data generated in connection therewith, (ii) chemical structure information for such Compound,
(iii) the draft IND for such Compound and all correspondence to and from any Regulatory Authority regarding such Compound, and (iv) the information and data set forth in Schedule 1.35 with respect to such Compound. 

1.65 “IND Milestone Payment” means, with respect to an Available Target, the milestone payment for milestone event
(0) specified in the table in Section 6.5.1 with respect to [**], and milestone payment for milestone event (0) specified in the table in Section 6.5.3 with respect to [**] and [**], as applicable. 

1.66 “IND Option Period” means, on an Available Target-by-Available Target basis, the period commencing on the Effective Date
and ending [**] days after receipt by CELGENE from EPIZYME of a complete IND Data Package with respect to a Development Candidate Directed to such Available Target, as such date may be extended pursuant to Section 2.8.3. 

1.67 “Indication” means any human disease or condition, or sign or symptom of a human disease or condition. 

1.68 “Initiation” means, with respect to a Clinical Trial, the first dosing of the first subject enrolled in such Clinical
Trial with a Licensed Product. 
 1.69 “Joint Collaboration Chemistry IP” means Joint Collaboration IP that is also
Chemistry IP. 

  
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 1.70 “Joint Collaboration IP” means, collectively: 

(a) “Joint Collaboration Know-How,” which means Know-How that is discovered, developed, invented, conceived or reduced to
practice by one or more employees, agents or consultants of EPIZYME, its Affiliates, Sublicensees or licensees, on the one hand, and one or more employees, agents or consultants of CELGENE, its Affiliates or Sublicensees, on the other hand, in the
conduct of activities under the Collaboration or in the exercise of each Party’s licenses under this Agreement, and that is not assigned to EPIZYME pursuant to Section 8.1.3(a) or to CELGENE pursuant to Section 8.1.3(b); and 

(b) “Joint Collaboration Patents,” which means Patents that Cover Joint Collaboration Know-How. 

1.71 “Joint Collaboration Non-Chemistry IP” means Joint Collaboration IP except Joint Collaboration Chemistry IP. 

1.72 “Know-How” means all tangible and intangible: 

(a) information, techniques, technology, practices, trade secrets, inventions (whether patentable or not), methods, knowledge, know-how,
skill, experience, data, results (including pharmacological, toxicological and clinical test data and results, research data, reports and batch records), analytical and quality control data, analytical methods (including applicable reference
standards), full batch documentation, packaging records, release, stability, storage and shelf-life data, and manufacturing process information, results or descriptions, software and algorithms; 

(b) compositions of matter, cells, cell lines, assays, animal models and physical, biological or chemical material; and 

(c) all derivatives, modifications and improvements of the foregoing. 

As used in this Agreement, “clinical test data” shall be deemed to include all information related to clinical or non-clinical testing, including
patient report forms, investigators’ reports, biostatistical, pharmaco-economic and other related analyses, regulatory filings and communications, and the like. 

1.73 “Lapsed Target” means (a) any Available Target as to which CELGENE exercises termination rights pursuant to
Section 2.8.5, and (b) any Available Target as to which CELGENE fails to exercise the IND Option and/or Phase 1 Option by the expiration of the IND Option Period and/or Phase 1 Option Period, as applicable, other than Available Targets
that become Selected Targets pursuant to Section 2.4. 
 1.74 “Law” or “Laws” means all laws,
statutes, rules, regulations, orders, judgments, or ordinances having the effect of law of any federal, national, multinational, state, provincial, county, city or other political subdivision. 

1.75 “Lead Candidate” means, with respect to a particular Available Target, a Compound Directed to such Available Target that
is selected by the JRC pursuant to Section 2.3.4 as meeting the applicable Lead Candidate Criteria, or is otherwise designated a Lead Candidate pursuant to Section 2.3.4. 

  
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 1.76 “Lead Candidate Criteria” means the criteria set forth on Schedule
1.76, as such criteria may be amended from time to time upon mutual agreement of the Parties. 
 1.77 “Lead Candidate
Product” means, on a Lapsed Target-by-Lapsed Target basis, as applicable, any pharmaceutical product comprising a Compound Directed to the applicable Lapsed Target, which Compound (a) is based upon or derived from a [**], (b) is
identified, synthesized or otherwise discovered during the conduct of the Collaboration during the applicable [**], (c) was determined to satisfy the Lead Candidate Criteria pursuant to Section 2.3.4 prior to the expiration of the
applicable Selection Term, and (d) did not meet the Development Candidate Selection Criteria pursuant to Section 2.3.5 prior to or as of the expiration of the Selection Term; provided that (y) in the event such [**] at
the time of introduction into the Collaboration pursuant to Section 2.3.2(a)(iii) meets the Lead Candidate Criteria, any pharmaceutical product comprising such [**] Directed to the applicable Lapsed Target shall be deemed a Lead Candidate
Product, and (z) in the event (i) a [**] is introduced into the Collaboration pursuant to Section 5.3 or becomes a [**] pursuant to the last sentence of Section 5.3, (ii) the applicable Selected Target becomes a Terminated
Target, (iii) such [**] did meet the Lead Candidate Criteria pursuant to Section 2.3.4 as of the date of expiration of the applicable Selection Term, or as of the date of such determination pursuant to Section 5.3, and (iv) such
[**] did not meet the Development Candidate Selection Criteria pursuant to Section 2.3.5 as of the date of termination, then any pharmaceutical product comprising such [**] Directed to the applicable Terminated Target shall be deemed a Lead
Candidate Product. For the avoidance of doubt, [**]. 
 1.78 “Legal Exclusivity” means, with respect to a Licensed Product,
(a) Patent-Based Exclusivity or (b) Regulatory-Based Exclusivity. 
 1.79 “License Event” means EPIZYME licenses
its rights to (a) an Available Target to a Third Party or (b) a Licensed Compound or Licensed Product to a Third Party in the EPIZYME Territory. 

1.80 “Licensed Compound(s)” means 

(a) any Compound that is: 

(i) identified, synthesized or otherwise discovered by either Party (or by any of its respective Affiliates or any Third Party working with
or on behalf of such Party or any of its respective Affiliates) in the conduct of the Collaboration or in the exercise of such Party’s licenses under this Agreement; 

(ii) Directed to a Selected Target (or, for purposes of Section 5.1.2, the applicable Available Target); and 

(iii) determined to have an in vitro IC50 enzymatic potency of less than or equal to
[**] for the Selected Target (or, for purposes of Section 5.1.2, the applicable Available Target) and is determined to have an in vitro enzymatic IC50 that is greater than [**] against any
other Target; 
 (b) a Related Compound with respect to the Compound described in the foregoing clause (a). 

  
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 The Parties shall negotiate in good faith to determine if a cross-inhibitory profile is desired for a respective
Selected Target, in which case the Parties shall mutually agree to amend Section 1.80(a)(iii) pursuant to the terms of this Agreement to modify the selectivity threshold set forth in Section 1.80(a)(iii). 

1.81 “Licensed Product(s)” means any pharmaceutical product comprising a Licensed Compound, whether or not as the sole active
ingredient and in any dosage form or formulation, excluding Diagnostic Products. 
 1.82 “LLS” means The Leukemia and
Lymphoma Society. 
 1.83 “LLS Agreement” means the Definitive Agreement, dated June 17, 2011, by and between LLS and
EPIZYME. 
 1.84 “MAA” means a regulatory application filed with the EMA or MHLW seeking Regulatory Approval of a Licensed
Product, and all amendments and supplements thereto filed with the EMA or MHLW. 
 1.85 “Major EU Country” means any of the
following countries: France, Germany, Italy, Spain or the United Kingdom. “Major EU Countries” means all of the foregoing countries. 

1.86 “Manufacture” or “Manufacturing” means, as applicable, all activities associated with the production,
manufacture, supply, processing, filling, packaging, labeling, shipping, and storage of a Compound (including Licensed Compound), Licensed Product, Diagnostic Product or any components thereof, including manufacturing process and formulation
development and scale-up (including active pharmaceutical ingredient and drug production), manufacturing process validation, stability testing, preclinical, clinical and commercial manufacture and analytical development, product characterization,
quality assurance and quality control development, testing and release. 
 1.87 “MHLW” means the Ministry of Health, Labour
and Welfare of Japan, or the Pharmaceuticals and Medical Devices Agency, or any successor to either of them, as the case may be. 
 1.88
“MMRF” means The Multiple Myeloma Research Foundation, Inc. 
 1.89 “MMRF Agreement” means the Research
Agreement, dated June 15, 2011, by and between MMRF and EPIZYME. 

  
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 1.90 “NDA” means a New Drug Application (as more fully described in 21 C.F.R.
314.50 et seq. or its successor regulation) and all amendments and supplements thereto submitted to the FDA, or any equivalent filing, including an MAA, in a country or regulatory jurisdiction other than the United States with the applicable
Regulatory Authority. 
 1.91 “Net Sales” means with respect to any Licensed Product, the gross amounts invoiced by a
Party, its Affiliates and Sublicensees (each, a “Selling Party”) to Third Party customers for sales of such Licensed Product, less the following deductions actually incurred, allowed, paid, accrued or specifically allocated in its
financial statements in accordance with (as applicable to the Selling Party) Accounting Principles, for: 
 (a) discounts (including trade,
quantity and cash discounts) actually allowed, cash and non-cash coupons, retroactive price reductions, and charge-back payments and rebates granted to any Third Party (including to governmental entities or agencies, purchasers, reimbursers,
customers, distributors, wholesalers, and group purchasing and managed care organizations or entities (and other similar entities and institutions)); 

(b) credits or allowances, if any, on account of price adjustments, recalls, claims, damaged goods, rejections or returns of items previously
sold (including Licensed Product returned in connection with recalls or withdrawals) and amounts written off by reason of uncollectible debt, provided that if the debt is thereafter paid, the corresponding amount shall be added to the
Net Sales of the period during which it is paid; 
 (c) rebates (or their equivalent), administrative fees, chargebacks and retroactive
price adjustments and any other similar allowances granted by a Selling Party (including to governmental authorities, purchasers, reimburses, customers, distributors, wholesalers, and managed care organizations and entities (and other similar
entities and institutions)) which effectively reduce the selling price or gross sales of the Licensed Product; 
 (d) insurance, customs
charges, freight, postage, shipping, handling, and other transportation costs incurred by a Selling Party in shipping Licensed Product to a Third Party; 

(e) import taxes, export taxes, excise taxes (including annual fees due under Section 9008 of the United States Patient Protection and
Affordable Care Act of 2010 (Pub. L. No. 111-48) and other comparable Laws), sales taxes, value-added taxes, consumption taxes, duties or other taxes levied on, absorbed, determined and/or imposed with respect to such sales (excluding income or
net profit taxes or franchise taxes of any kind); and 
 (f) reasonable discounts due to factoring of receivables owed by account debtors
identified by the Selling Party as habitually failing to adhere to customary payment terms, which discounts are incurred consistent with the Selling Party’s practices with respect to the Selling Party’s other pharmaceutical products sold
to such account debtors; provided that such discounts are then applied as a result of factoring of receivables in a manner consistent with the Accounting Principles applied by the Selling Party and reflected in the Selling Party’s
financial statements for non-Licensed Product sales to the same account debtors. 

  
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 There shall be no double counting in determining the foregoing deductions from gross amounts invoiced to
calculate Net Sales. The calculations set forth in this Section 1.91 shall be determined in accordance with the Selling Party’s Accounting Principles. 

If non-monetary consideration is received by a Selling Party for any Licensed Product, Net Sales will be calculated based on the average price charged for
such Licensed Product, as applicable, during the preceding royalty period, or in the absence of such sales, the fair market value of the Licensed Product, as applicable, as determined by the Parties in good faith. If the Parties are unable to reach
such an agreement, the Parties shall refer such matter to a jointly selected Third Party with expertise in the pricing of pharmaceutical products that is not, and has not in the past [**] years been, an employee, consultant, legal advisor, officer,
director or stockholder of, and does not have any conflict of interest with respect to, either Party for resolution. Notwithstanding the foregoing, Net Sales shall not be imputed to transfers of Licensed Products, as applicable, for use in Clinical
Trials, non-clinical Development activities or other Development activities with respect to Licensed Products by or on behalf of the Parties, for bona fide charitable purposes or for compassionate use or for Licensed Product samples, if no monetary
consideration is received for such transfers. 
 Net Sales shall be determined on, and only on, the first sale by a Party or any of its Affiliates or
Sublicensees to a non-Sublicensee Third Party. 
 If a Licensed Product is sold as part of a Combination Product (as defined below), Net Sales will be the
product of (i) Net Sales of the Combination Product calculated as above (i.e., calculated as for a non-Combination Product) and (ii) the fraction (A/(A+B)), where: 

“A” is the gross invoice price in such country of the Licensed Product comprising a Licensed Compound as the sole therapeutically active ingredient;
and 
 “B” is the gross invoice price in such country of the other therapeutically active ingredients contained in the Combination Product. 

If “A” or “B” cannot be determined by reference to non-Combination Product sales as described above, then Net Sales will be calculated as
above, but the gross invoice price in the above equation shall be determined by mutual agreement reached in good faith by the Parties prior to the end of the accounting period in question based on an equitable method of determining the same that
takes into account, in the applicable country, variations in dosage units and the relative fair market value of each therapeutically active ingredient in the Combination Product. If the Parties are unable to reach such an agreement prior to the end
of the applicable accounting period, the Parties shall refer such matter to a jointly selected Third Party with expertise in the pricing of pharmaceutical products that is not, and has not in the past [**] years been, an employee, consultant, legal
advisor, officer, director or stockholder of, and does not have any conflict of interest with respect to, either Party for resolution. 
 As used in this
Section 1.91, “Combination Product” means a Licensed Product that contains one or more additional active ingredients (whether coformulated or copackaged) that are neither Licensed Compounds nor generic or other non-proprietary
compositions of matter. Pharmaceutical dosage form vehicles, adjuvants and excipients shall be deemed not to be “active ingredients”. 

  
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 1.92 “[**]” means the Targets described on Schedule 1.92. 

1.93 “Option Term” means the period commencing on the Effective Date and continuing until the latest of (a) three
(3) years from the Effective Date, (b) the End of Phase 1 Date with respect to the second Available Target for which EPIZYME has provided a complete Phase 1 Data Package to CELGENE pursuant to Section 2.8.4 and (c) two
(2) years after the End of Phase 1 Date with respect to the first Available Target for which EPIZYME has provided a complete Phase 1 Data Package to CELGENE pursuant to Section 2.8.4. 

1.94 “Out-of-Pocket Costs” means, with respect to activities performed under the applicable Research Plan or, with respect to
a Shared Development Program, Development Plan hereunder, the direct costs and expenses of either Party or its Affiliates that are specifically associated with the conduct of such activities and paid to a Third Party (and for clarity, Third Party
does not include a Party’s employees), including costs of consultants, agents and subcontractors, recorded in accordance with applicable Accounting Principles. 

1.95 “Patent” means (a) all patents and patent applications in any country or supranational jurisdiction worldwide,
(b) any substitutions, divisionals, continuations, continuations-in-part, reissues, renewals, registrations, confirmations, re-examinations, extensions, supplementary protection certificates and the like of any such patents or patent
applications, and (c) foreign counterparts of any of the foregoing. 
 1.96 “Patent-Based Exclusivity” means with
respect to a Licensed Product in a country, that at least one Valid Claim of the EPIZYME Patents, the CELGENE Provided Compound Patents, the CELGENE Collaboration Patents or the Joint Collaboration Patents Covers the composition of matter, method of
use or formulation of such Licensed Product in such country. 
 1.97 “Person” means any individual, partnership, joint
venture, limited liability company, corporation, firm, trust, association, unincorporated organization, governmental authority or agency, or any other entity not specifically listed herein. 

1.98 “Phase 1 Clinical Trial” means a human clinical trial of a product in any country, the principal purpose of which is to
determine the metabolism and pharmacological actions of the product in humans, the side effects associated with increasing doses and, if possible, to gain early evidence of effectiveness, as described in 21 C.F.R. 312.21(a), or a similar clinical
study prescribed by the relevant Regulatory Authorities in a country other than the United States. 
 1.99 “Phase 1 Data
Package” means, with respect to a Compound directed to an Available Target, the following: (i) the final and complete clinical study report for the Phase 1 Clinical Trial of such Compound, based on an analysis performed on the complete
and cleaned dataset from such Phase 1 Clinical Trial, (ii) chemical structure information for such Compound, (iii) all safety and efficacy data generated with respect to such Compound and all correspondence


  
 - 17 - 








 
to and from any Regulatory Authority regarding such Compound, and (iv) a reasonably detailed summary of any other research and development activities conducted with respect to such Compound,
including any data generated in connection therewith; provided that, EPIZYME shall use Commercially Reasonable Efforts to conduct a follow-up of patients in the Phase I Clinical Trial of such Compound, as set forth in the applicable protocol, and
shall include the results of any such follow-up that is conducted in the Phase 1 Data Package to the extent available at such time as the Phase 1 Data Package is otherwise complete. 

1.100 “Phase 1 Option Period” means, on an Available Target-by-Available Target basis, the period commencing on the Effective
Date and ending on the End of Phase 1 Date. 
 1.101 “Phase 2 Clinical Trial” means a human clinical trial of a product in
any country that would satisfy the requirements of 21 C.F.R. 312.21(b) and is intended to explore a variety of doses, dose response, and duration of effect, and to generate evidence of clinical safety and effectiveness for a particular Indication or
Indications in a target patient population, or a similar clinical study prescribed by the relevant Regulatory Authorities in a country other than the United States. 

1.102 “Phase 3 Clinical Trial” means a human clinical trial of a product in any country that would satisfy the requirements
of 21 C.F.R. 312.21(c) and is intended to (a) establish that the product is safe and efficacious for its intended use, (b) define contraindications, warnings, precautions and adverse reactions that are associated with the product in the
dosage range to be prescribed, and (c) support Regulatory Approval for such product; or a similar clinical study prescribed by the relevant Regulatory Authorities in a country other than the United States. 

1.103 “Pivotal Clinical Trial” means a human clinical trial of a compound on a sufficient number of subjects that satisfies
both of the following ((a) and(b)): 
 (a) such trial is designed to establish that such compound has an acceptable safety and efficacy
profile for its intended use, and to determine warnings, precautions, and adverse reactions that are associated with such compound in the dosage range to be prescribed, which trial is intended to support Regulatory Approval of such compound, or a
similar clinical study prescribed by the EMA or another Regulatory Authority; and 
 (b) either (i) such trial is a Phase 3 Clinical
Trial that is intended by the JDC to be submitted (together with any other registration trials that are prospectively planned when such Phase 3 Clinical Trial is Initiated) for centralized Regulatory Approval to the EMA for the EU or for Regulatory
Approval by the applicable Regulatory Authority in any of the Major EU Countries, or (ii) such trial is a registration trial intended to be sufficient for filing an application for a Regulatory Approval for such compound in the United States or
another country or some or all of an extra-national territory, solely as evidenced by the acceptance for filing for a Regulatory Approval for such compound after completion of such trial. 

1.104 “Product Liability” means any product liability claims asserted or filed by a Third Party (without regard to their
merit or lack thereof), seeking damages or equitable relief of any kind, relating to personal injury, wrongful death, medical expenses, an alleged need for medical 

  
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monitoring, consumer fraud or other alleged economic losses, allegedly caused by any Licensed Product, and including claims by or on behalf of users of any Licensed Product (including spouses,
family members and personal representatives of such users) relating to the use, sale, distribution or purchase of any Licensed Product sold by CELGENE, its Affiliates, Sublicensees or distributors, or by EPIZYME, its Affiliates, Sublicensees or
distributors, as applicable, including claims by Third Party payers, such as insurance carriers and unions. 
 1.105 “Prosecution
and Maintenance” or “Prosecute and Maintain” means, with regard to a Patent, the preparation, filing, prosecution and maintenance of such Patent, as well as re-examinations, reissues, appeals, and requests for patent term
adjustments and patent term extensions with respect to such Patent, together with the initiation or defense of interferences, the initiation or defense of oppositions and other similar proceedings with respect to the particular Patent, and any
appeals therefrom. For clarification, “Prosecution and Maintenance” or “Prosecute and Maintain” shall not include any other enforcement actions taken with respect to a Patent. 

1.106 “Regulatory Approval” means the approval, license or authorization of the applicable Regulatory Authority necessary for
the marketing and sale of a product for a particular Indication in a country in the world, including separate pricing or reimbursement approvals that may be legally required in order to sell the product in such country, and including the approval by
the applicable Regulatory Authority of any expansion or modification of the label for such Indication. 
 1.107 “Regulatory
Authority” means the FDA in the U.S. or any health regulatory authority in any country in the CELGENE Territory or EPIZYME Territory that is a counterpart to the FDA and holds responsibility for granting Regulatory Approval for a product in
such country, including the EMA and the MHLW, and any successor(s) thereto. 
 1.108 “Regulatory-Based Exclusivity” means
with respect to a Licensed Product in a country, that (a) CELGENE or any of its Affiliates or Sublicensees has been granted the exclusive legal right by a Regulatory Authority (or is otherwise entitled to the exclusive legal right by operation
of Law) in such country to market and sell the Licensed Product or the active ingredient comprising such Licensed Product in such country, or (b) the data and information submitted by CELGENE or any of its Affiliates or Sublicensees to the
relevant Regulatory Authority in such country for purposes of obtaining Regulatory Approval may not be disclosed, referenced or relied upon in any way by such Regulatory Authority (including by relying upon the Regulatory Authority’s previous
findings regarding the safety or effectiveness of the Licensed Product) to support the Regulatory Approval or marketing of any product by a Third Party in such country. 

1.109 “Regulatory Materials” means the regulatory registrations, applications, authorizations and approvals (including
approvals of NDAs, supplements and amendments, pre- and post-approvals, pricing and Third Party reimbursement approvals, and labeling approvals), Regulatory Approvals or other submissions made to or with any Regulatory Authority necessary for the
research, Development (including the conduct of clinical studies), Manufacture, or Commercialization of a Licensed Compound, Licensed Product or Diagnostic Product in a 

  
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regulatory jurisdiction, together with all related correspondence to or from any Regulatory Authority and all documents referenced in the complete regulatory chronology for each NDA, including
all Drug Master File(s) (if any), IND, CTA, MAA and supplemental new drug applications (sNDAs) or foreign equivalents of any of the foregoing. 

1.110 “Related Compound” means, with respect to a Compound, any salt, free acid, free base, clathrate, solvate, hydrate,
hemihydrates, anhydride, ester, chelate, conformer, congener, crystal form, crystal habit, polymorph, amorphous solid, homolog, isomer, stereoisomer, enantiomer, racemate, prodrug, isotopic or radiolabeled equivalent, metabolite, conjugate, complex
or mixture, of such Compound. 
 1.111 “Research Plan” means a research plan governing the activities of the Collaboration
to be conducted by the Parties during the Option Term, with the goal of identifying Compounds Directed to the Available Targets that meet the applicable Development Candidate Selection Criteria and advancing such Compounds to completion of Phase 1
Clinical Trial (including completion of a Phase 1 Data Package therefor). 
 1.112 “Selection Term” means, on an Available
Target-by-Available Target basis, the period commencing on the Effective Date and ending on the earliest of (a) the expiration of the IND Option Period with respect to such Available Target, unless CELGENE has exercised the IND Option with
respect to such Available Target, (b) the applicable End of Phase 1 Date with respect to such Available Target, (c) the end of the Option Term, (d) the date that such Available Target becomes a Lapsed Target, or (e) the date that
such Available Target becomes a Selected Target. 
 1.113 “Shared Development Program” means, for DOT1L or [**], the
activities performed or to be performed by the Parties, their Affiliates and Sublicensees, in accordance with the applicable Development Plan and the approved budget and under the overall direction of the JDC, to Develop Licensed Compounds and
Licensed Products Directed to such Target after (a) in the case of DOT1L, such Target became a Selected Target pursuant to the Original Agreement, and (b) in the case of [**], such Target becomes a Selected Target, and in each case of
(a) and (b), related Diagnostic Products, in the Field during the applicable Development Term. For clarity, a Shared Development Program as to which EPIZYME exercises an EPIZYME Post-EOP1 Clinical Opt-Out pursuant to Section 2.5 or an
EPIZYME Late Stage Opt-Out pursuant to Section 2.6 shall constitute a “CELGENE Development Program”. 
 1.114
“Sublicensee” means (a) with respect to CELGENE, a Third Party to whom CELGENE has granted a license under Know-How or Patents Controlled by CELGENE, or a sublicense under Know-How or Patents licensed to CELGENE pursuant to
this Agreement, to research, Develop, Manufacture or Commercialize Compounds (including Licensed Compounds), Licensed Products or Diagnostic Products in the Field, and (b) with respect to EPIZYME, a Third Party to whom EPIZYME has granted a
license under Know-How or Patents Controlled by EPIZYME, or a sublicense under Know-How or Patents licensed to EPIZYME pursuant to this Agreement, to research, Develop, Manufacture or Commercialize Compounds (including Licensed Compounds), Licensed
Products or Diagnostic Products in the Field; but in each case excluding any Third Party acting solely as a distributor. For purposes of clarity, none 

  
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of EPIZYME, its Affiliates, Sublicensees and other licensees shall be deemed a Sublicensee of CELGENE; and none of CELGENE, its Affiliates and Sublicensees shall be deemed a Sublicensee of
EPIZYME. 
 1.115 “[**]” means the Target described on Schedule 1.115. 

1.116 “[**]” means the Target described on Schedule 1.116. 

1.117 “Target” means an HMT, which is a class of enzymes characterized from either biochemical experiments with purified
protein or sequence homology analyses indicating their ability to transfer methyl groups to either specific lysine or arginine residues of histone proteins using S-adenosyl-L-methionine as the methyl group donor. 

1.118 “Territory-Specific Development Costs” means any Development Costs that are incurred in connection with Development
activities specifically related only to the EPIZYME Territory (in which event such costs shall be the responsibility of EPIZYME) or to the CELGENE Territory (in which event such costs shall be the responsibility of CELGENE). 

1.119 “Third Party” means any Person other than EPIZYME or CELGENE that is not an Affiliate of EPIZYME or of CELGENE. 

1.120 “UNC” means The University of North Carolina at Chapel Hill. 

1.121 “UNC Agreement” means the License Agreement, dated January 7, 2008, by and between UNC and EPIZYME. 

1.122 “United States” or “U.S.” means the United States of America and all of its territories and
possessions. 
 1.123 “Valid Claim” means: 

(a) a claim of an issued patent in the U.S. or in a jurisdiction outside the U.S., as applicable, that has not expired, lapsed, been
cancelled or abandoned, or been dedicated to the public, disclaimed, or held unenforceable, invalid, revoked or cancelled by a court or administrative agency of competent jurisdiction in an order or decision from which no appeal has been or can be
taken, including through opposition, reexamination, reissue or disclaimer; or 
 (b) a claim of a pending patent application that has not
been finally abandoned or finally rejected or expired and which has been pending for no more than [**] years from the date of filing of the earliest priority patent application to which such pending patent application is entitled to claim benefit.

 For clarity, a claim of an issued patent that ceased to be a Valid Claim before it issued because it had been pending too long, but subsequently issued
and is otherwise described by clause (a) of the foregoing sentence shall again be considered to be a Valid Claim once it issues. The same principle shall apply in similar circumstances such as if, for example (but without limitation), a final
rejection of a claim is overcome. 

  
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 1.124 Additional Definitions. Each of the following definition is set forth in the section
of this Agreement indicated below: 
  

			
	 Definition:
	 	 Section:

		
	Additional Payments	 	1.30
	 Adverse Study Effect
 Agreement
	 	 3.2.2(c)
 Preamble

	Alliance Manager	 	4.6
	Arbitration Dispute	 	13.1
	Arbitration Request	 	13.2
	Arbitrator	 	13.2.1
	Bankruptcy Code	 	5.5
	Breaching Party	 	12.3.1(a)
	Budgeted Costs	 	6.3.2(a)
	Business Acquisition	 	7.1.3(a)
	Business Party	 	7.1.3(a)
	Business Program	 	7.1.3(a)
	CELGENE	 	Preamble
	CELGENE Background Know-How	 	1.10(a)
	CELGENE Background Patents	 	1.10(b)
	CELGENE Collaboration Know-How	 	1.11(a)
	CELGENE Collaboration Patents	 	1.11(b)
	CELGENE Indemnitees	 	11.2
	CELGENE Lead Candidate	 	5.3
	Celgene Obligations	 	13.21
	CELGENE Patent Challenge	 	12.4.1(b)
	CELGENE Provided Compound Transfer Agreement	 	2.3.2(a)(iii)(5)
	Claims	 	11.1
	Collaboration	 	2.2
	Combination Product	 	1.91
	 Competitive Infringement
 [**]
	 	 8.5.1
 7.1.3(b)

	Confidential Information	 	9.1
	CRO	 	2.3.2(a)(iii)(1)
	CTA	 	1.63
	 Development Cost Share
 Development Program
Stopping Rules
	 	 6.3.1
 2.3.7

	Disclosing Party	 	9.1
	Discontinued Product	 	6.5.7
	Effective Date	 	Preamble


  
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	 Definition:
	 	 Section:

		
	 EOP1 License Option Payment
 EPIZYME
	 	 2.9.3
 Preamble

	EPIZYME Agreements	 	10.2(b)
	EPIZYME Background Know-How	 	1.49(a)
	EPIZYME Background Patents	 	1.49(b)
	EPIZYME Collaboration Know-How	 	1.50(a)
	EPIZYME Collaboration Patents	 	1.50(b)
	EPIZYME In-Licenses	 	10.2(b)
	EPIZYME Indemnitees	 	11.1
	EPIZYME Late Stage Opt-Out	 	2.6.1
	EPIZYME Late Stage Opt-Out Date	 	2.6.1(b)
	 EPIZYME Patent Challenge
 EPIZYME Post-EOP1
Clinical Opt-Out
 EPIZYME Post-EOP1 Clinical Opt-Out Date

EPIZYME Pre-IND Opt-Out
 EPIZYME Pre-IND Opt-Out Date
	 	 12.4.2(b)
 2.5.1

2.5.1
 2.4.1

2.4.1

	 EPIZYME Research Tools
 GAAP

Global Development Lead
	 	 2.4.2(b)(ii)(1)
 1.1

3.1

	Hit Criteria	 	2.3.2(a)(iii)(1)
	IFRS	 	1.1
	IND Notice of Exercise	 	2.9.1
	IND Option	 	2.9.1
	 IND License Option Payment
 Indemnification
Claim Notice
	 	 2.9.1
 11.3.1

	Indemnified Party	 	11.3.1
	Indemnifying Party	 	11.3.1
	Initial Hit	 	2.3.2(a)(iii)(1)
	JCC	 	4.3
	JDC	 	4.2
	Joint Collaboration Know-How	 	1.70(a)
	Joint Collaboration Patents	 	1.70(b)
	JRC	 	4.1
	Key Employee	 	13.14
	Know-How Royalty	 	6.6.2(b)
	Litigation Conditions	 	11.3.2
	Losses	 	11.1
	M&A Event	 	13.5
	Major License Countries	 	2.12.3(b)(i)
	Manufacturing Subcommittee	 	4.4.3(a)
	Material Breach	 	12.3.1
	Material Receiving Party	 	2.12.5(a)
	Materials	 	2.12.5(a)


  
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	 Definition:
	 	 Section:

		
	Non-Breaching Party	 	12.3.1(a)
	Non-Paying Party	 	6.4
	Non- Disclosing Party	 	9.3.2
	Non-Proposing Party	 	3.2.2(b)
	 [**] IND License Option Payment
 [**] EOP1
License Option Payment
	 	 6.5.1
 6.5.1

	[**] Study	 	3.2.2(a)
	Once Confirmed Hit	 	2.3.2(a)(iii)(2)
	PARENT	 	Preamble
	Party or Parties	 	Preamble
	Patent Committee	 	4.5
	Patent Liaison	 	4.5
	Patent Strategy	 	4.5.5(b)
	Payee	 	6.8.1
	Payor	 	6.8.1
	Phase 1 Notice of Exercise	 	2.9.3
	Phase 1 Option	 	2.9.2
	Post-Regulatory Approval Opt-Out Period	 	2.6.1(b)
	Pre-NDA Opt-Out Period	 	2.6.1(a)
	Pre-Pivotal Opt-Out Period	 	2.6.1(a)
	Pre-Regulatory Approval Opt-Out Period	 	2.6.1(a)
	Proposing Disclosing Party	 	9.3.2
	Proposing Party	 	3.2.2(a)
	Publishing Party	 	9.5.2
	Purpose	 	2.12.5(a)
	Receiving Party	 	9.1
	Registrational Use	 	6.6
	Research License	 	2.4.2(b)(ii)(2)
	Residual Information	 	9.1(d)
	Reviewing Party	 	9.5.2
	Royalty Term	 	6.6.2(a)
	Second Indication	 	6.5.3
	Selected Target(s)	 	2.9.2
	Selling Party	 	1.91
	Sensitive Information	 	7.1.3(a)
	Sole Paying Party	 	6.4
	Subcommittee	 	4.4.3
	 [**] IND License Option Payment
 [**] EOP1
License Option Payment
	 	 6.5.3
 6.5.3

	Terminated Country	 	12.6.1
	Terminated Products	 	12.6.1
	Terminated Target	 	12.6.1
	Transfer Record	 	2.12.5(a)


  
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	 Definition:
	 	 Section:

		
	Transferring Party	 	2.12.5(a)
	Twice Confirmed Hit	 	2.3.2(a)(iii)(4)
	US Rights Event	 	2.7.2(a)

 ARTICLE 2 

AMENDMENT AND RESTATEMENT; COLLABORATION; RESEARCH PLAN; OPT-OUTS 

2.1 Amendment and Restatement. 

2.1.1 Effective as of the Effective Date, this Agreement amends, supersedes and restates the Original Agreement in all respects. 

2.1.2 From and after the Effective Date, the Original Agreement shall be of no further force or effect, provided that: 

(a) any and all liabilities, damages and remedies (whether in law or in equity) arising from any breach of, and all indemnification
obligations arising under, the Original Agreement shall survive; 
 (b) any Materials transferred by a Transferring Party to a Material
Receiving Party under Section 2.7.5 of the Original Agreement shall be deemed transferred to the Material Receiving Party under Section 2.12.5 of this Agreement, and any other Materials shall be subject to Section 2.12.5(b) of this
Agreement; provided, that, as of the Effective Date the only Materials transferred under Section 2.8.5 of the Original Agreement were Materials relating to DOT1L; 

(c) any Collaboration IP and Joint Collaboration IP arising under the Original Agreement shall be deemed Collaboration IP and Joint
Collaboration IP under this Agreement; 
 (d) any Confidential Information disclosed under the Original Agreement or deemed to be disclosed
thereunder pursuant to Section 9.4 thereof shall be deemed Confidential Information disclosed under this Agreement; 
 (e) the
following Sections and Article shall survive under the Original Agreement with respect to activities performed or obligations or payments due under the Original Agreement prior to the Effective Date: Sections 2.7.1, 2.7.5(d)-(f), 6.11, 6.13, 6.14,
8.1, 8.8, Articles 9, 11 (with respect to matters occurring prior to the Effective Date) and 13; and 
 (f) notwithstanding anything to the
contrary in the Original Agreement, the only terms of the Original Agreement that survive the amendment and restatement thereof are set forth in this Section 2.1 and, for the avoidance of doubt, Article 7 of the Original Agreement shall not
survive such amendment and restatement. 

  
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 2.1.3 The Parties further agree that in connection with the Original Agreement: 

(a) no CELGENE Provided Compounds were introduced into the Collaboration and, consequently, no CELGENE Provided Compound IP or CELGENE
Provided Compound Patents were introduced into or licensed under the Original Agreement; 
 (b) no CELGENE Background Know-How was provided
by CELGENE to the Collaboration, and consequently, no CELGENE Background Patents were introduced into or licensed under the Original Agreement; 

(c) no Targets as defined under the Original Agreement shall be deemed Lapsed Targets, except for any such Targets that are Available Targets
or Selected Targets under this Agreement and that become Lapsed Targets pursuant to this Agreement; 
 (d) only the Targets that are DOT1L,
[**] are subject to the Collaboration under this Agreement; and 
 (e) there are no amounts payable under Section 6.3.2 by a Party to
the other Party pursuant to Section 6.5 of the Original Agreement for Development Cost Share accrued prior to the Effective Date, other than the [**] in the amount of [**] Dollars ($[**]) payable by CELGENE to EPIZYME. 

2.2 Collaboration Overview. Pursuant to this Agreement (including the Research Plan and the Development Plans) and as further provided
in this Article 2 and Article 3, the Parties shall collaborate on (a) the conduct of platform discovery activities under the Research Plan with the goal of identifying Compounds Directed to the Available Targets that meet the applicable
Development Candidate Selection Criteria and (b) the conduct of Development activities directed to Selected Targets under the applicable Development Plan as set forth in Article 3 (the “Collaboration”). 

2.3 Research Plan; Research Activities. 

2.3.1 Research Plan. The initial Research Plan is attached hereto as Exhibit A. 

2.3.2 Responsibilities. 

(a) EPIZYME Responsibilities. During the Option Term: 

(i) EPIZYME shall use Commercially Reasonable Efforts to conduct platform discovery activities necessary to characterize and identify
Compounds Directed to Available Targets. In addition, EPIZYME shall be primarily responsible for the research strategy and the conduct of activities under the Research Plan. EPIZYME shall use Commercially Reasonable Efforts to perform the activities
assigned to EPIZYME under the Research Plan. 
 (ii) As between the Parties, EPIZYME shall be primarily responsible for the identification
and generation of Compounds for which initial activities shall 

  
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be conducted by the Parties under the Research Plan. Either Party’s compound libraries and Compounds may be screened under the Collaboration in accordance with this Section 2.3.2(a)(ii)
and Section 2.3.2(a)(iii), provided that, any compound libraries and Compounds screened and any Know-How or Patents generated as a result of such screening shall be subject to ownership and assignment as provided in
Section 8.1. 
 (iii) CELGENE’s and its Affiliates’ compounds may be screened upon mutual agreement of the Parties, solely
in accordance with the following procedure: 
 (1) At any time prior to expiration of the Option Term, if the Parties mutually agree to
screen CELGENE’s and its Affiliates’ compounds against an Available Target, CELGENE shall provide such compounds as selected by CELGENE as de-identified coded samples to a Third Party contract research organization (the
“CRO”), mutually acceptable to the Parties, for screening against EPIZYME’s assays; provided that for such screening purposes, the identity and chemical structures of CELGENE’s compounds shall not be provided
to EPIZYME or the CRO. The Parties, acting through the JRC, shall mutually agree on hit criteria for the applicable Available Target (the “Hit Criteria”) and the CRO will provide the Parties with any compound(s) that meets the Hit
Criteria (each, an “Initial Hit”) and all relevant information related thereto, subject to the restrictions contained in the immediately preceding sentence. For the avoidance of doubt, CELGENE’s and its Affiliates’
compounds may not be screened after expiration of the Option Term. 
 (2) Upon CELGENE’s written request, EPIZYME will re-screen such
compound to confirm that it is an Initial Hit for the applicable Available Target, and if so confirmed, such Initial Hit shall be a “Once Confirmed Hit”. 

(3) Upon a CELGENE compound becoming a Once Confirmed Hit, CELGENE shall elect whether or not to introduce such compound into the
Collaboration and shall notify EPIZYME in writing of such election not later than [**] days after notification that such compound is a Once Confirmed Hit. 

(4) Promptly after CELGENE’s election to introduce such compound into the Collaboration, CELGENE shall re-synthesize such compound, and
then EPIZYME shall again confirm that the compound meets the Hit Criteria (a “Twice Confirmed Hit”). 
 (5) Upon receipt
by CELGENE of notice that such compound is a Twice Confirmed Hit, the Parties shall negotiate in good faith to execute a transfer agreement substantially in the form of Exhibit B (each, a “CELGENE Provided Compound Transfer
Agreement”), which shall list the identity and chemical structure of such compound; it being understood and agreed that no information or data relating to such CELGENE Provided Compound other than its identity and chemical structure as set
forth on the CELGENE Provided Compound Transfer Agreement is required to be disclosed or provided by CELGENE under this Agreement. Upon execution of the CELGENE Provided Compound Transfer Agreement, such compound shall be (A) deemed a Compound
and a CELGENE Provided Compound and (B) available for further research and Development under the Research Plan and, if applicable, the Development Plan for the applicable Selected Target. 

  
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 For the avoidance of doubt, (x) if CELGENE notifies EPIZYME prior to re-confirmation by EPIZYME as set forth
in subclause (4) above that CELGENE elects not to introduce a Once Confirmed Hit into the Collaboration or a Once Confirmed Hit fails to become a Twice Confirmed Hit, the applicable compound shall not be a Compound (except for purposes of
Section 7.1) or a CELGENE Provided Compound; (y) neither EPIZYME nor the CRO shall be permitted to cross-screen any compound(s) provided under subclause (1) against any other Available Target unless and until such compound(s) become
CELGENE Provided Compound(s) as set forth in this Section 2.3.2(a)(iii); and (z) subject to Section 8.1.3(a), any compound, including Compounds, Controlled by CELGENE or any of its Affiliates as of the Effective Date or thereafter
during the Term other than a Compound that is (I) provided to EPIZYME in accordance with this Section 2.3.2(a)(iii), or (II) based upon or derived from a Compound described in subclause (I) and that is synthesized, identified or
discovered during the conduct of the Collaboration in accordance with this Agreement, shall not be subject to the licenses set forth in Article 5. 

(b) CELGENE Responsibilities. Notwithstanding that EPIZYME is primarily responsible for the conduct of the activities set forth in the
Research Plan, and subject to Section 4.7, CELGENE shall be responsible for, and shall use Commercially Reasonable Efforts to perform, the activities assigned to CELGENE under the Research Plan. 

2.3.3 No Representation. Subject to the foregoing obligations to use Commercially Reasonable Efforts, neither Party provides any
representation, warranty or guarantee that the Collaboration will be successful, that any Hit Criteria, Lead Candidate Criteria or Development Candidate Selection Criteria will be achieved, or that any other particular results will be achieved with
respect to the Collaboration or any Available Target, Selected Target, Compound (including Licensed Compound), Licensed Product or Diagnostic Product hereunder. 

2.3.4 Selection of Lead Candidate. On an Available Target-by-Available Target basis (or, if such determination is made pursuant to the
final sentence of Section 5.3, on a Selected Target-by-Selected Target basis), the JRC shall, in good faith, determine whether or not a Compound satisfies the applicable Lead Candidate Criteria; provided that [**]. Upon
determination that any Compound satisfies the applicable Lead Candidate Criteria pursuant to the preceding sentence, such Compound shall be deemed the Lead Candidate for all purposes hereunder. 

2.3.5 Selection of Development Candidate. On an Available Target-by-Available Target or Selected Target-by-Selected Target basis, as
applicable, the JRC shall, in good faith, determine whether or not a Compound satisfies the applicable Development Candidate Selection Criteria; provided that [**]. Upon the earlier of: (i) determination that any Compound
satisfies the applicable Development Candidate Selection Criteria pursuant to the preceding sentence, or (ii) the effectiveness of an IND with respect to a Compound, such Compound shall be deemed a Development Candidate for all purposes
hereunder. On an Available Target-by-Available Target or Selected Target-by-Selected Target basis, as applicable, 

  
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once an applicable Compound has met the Development Candidate Selection Criteria or has been deemed to be a Development Candidate, subject to Sections 2.4 and 2.5, EPIZYME may, in its sole
discretion, develop a plan for conducting a Phase 1 Clinical Trial for such Development Candidate and such Available Target or Selected Target, as applicable, and shall retain final decision-making authority related thereto, subject to
CELGENE’s right to review and provide comments on the protocol related to such trial, which comments EPIZYME shall consider in good faith; provided that, if EPIZYME determines not to proceed with developing such a plan and
conducting such a Phase 1 Clinical Trial, such determination shall promptly be noticed by EPIZYME to CELGENE in writing and thereupon EPIZYME shall be deemed to have exercised an EPIZYME Pre-IND Opt-Out as to such Available Target pursuant to
Section 2.4. 
 2.3.6 Information Relating to [**]. Except as provided in Sections 2.3.4, 2.3.5, 2.4, 2.5, 2.6, 2.7, 2.8.3 and
2.8.4, until CELGENE’s exercise of the Phase 1 Option with respect to [**], EPIZYME shall not disclose any of EPIZYME’s Confidential Information to CELGENE or its Affiliates with respect to [**] or any Compounds Directed to [**]. If,
notwithstanding the foregoing, EPIZYME discloses any such EPIZYME Confidential Information to CELGENE or its Affiliates (other than, for clarity, pursuant to Sections 2.8.3 and 2.8.4), such Confidential Information shall not be considered
Confidential Information for purposes of this Agreement and CELGENE and its Affiliates shall not have any obligation of confidentiality or non-use under Article 9 with respect to such Confidential Information. 

2.3.7 Stopping Rules. On a Shared Development Program-by-Shared Development Program basis and, as to Available Targets for which
EPIZYME is responsible for conducting a Phase 1 Clinical Trial, on a Phase 1 Clinical Trial-by-Phase 1 Clinical Trial basis, [**]. 
 2.4
EPIZYME Pre-IND Opt-Out. 
 2.4.1 Notice of Pre-IND Opt-Out. On an Available Target-by-Available Target basis, after
completion of the initial Research Plan and prior to the filing of an IND for a Development Candidate Directed to such Available Target, if EPIZYME determines not to proceed with further research or Development of Compound(s) Directed to such
Available Target for any reason (including, without limitation, safety or efficacy concerns, the lack of viable Indications with respect to such targets and other technical or scientific reasons), EPIZYME shall, after discussing the matter within
the JRC, have the right, in its sole discretion, to exercise an “EPIZYME Pre-IND Opt-Out”, pursuant to which EPIZYME shall have no further right or obligation to participate in any research or Development-related activities with
respect to such Available Target, except as provided in Section 2.4.2(b)(iv). EPIZYME may exercise the EPIZYME Pre-IND Opt-Out by providing written notice to CELGENE of such election, which opt-out shall take effect [**] days after the date of
such written notice (the “EPIZYME Pre-IND Opt-Out Date”). 
 2.4.2 Effect of EPIZYME Pre-IND Opt-Out. 

(a) In the event that CELGENE wishes to continue research and/or Development of an applicable Available Target and Compounds, Licensed
Compounds and 

  
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Licensed Products Directed thereto after EPIZYME exercises an EPIZYME Pre-IND Opt-Out or after EPIZYME exercises an EPIZYME Post-EOP1 Clinical Opt-Out in accordance with clause (iii) of
Section 2.5.1, CELGENE may elect to do so in its sole discretion at its sole cost and expense within [**] days after EPIZYME’s exercise of the applicable EPIZYME Pre-IND Opt-Out or EPIZYME Post-EOP1 Clinical Opt-Out in accordance with
clause (iii) of Section 2.5.1, which election CELGENE shall promptly notice to EPIZYME in writing within such [**] day period. Upon such election by CELGENE, the applicable Available Target shall be deemed to be a Selected Target and, as
to such Selected Target, the CELGENE Territory shall be the entire world, and the license under Section 5.1.3 shall automatically be deemed granted with respect to Compounds, Licensed Compounds and Licensed Products Directed to such Selected
Target. In such event, economic terms applicable to such Selected Target shall be modified as follows: (A) to the extent not paid prior to such election, the Development milestone payments (0) and (1), as set forth in Sections 6.5.1 and
6.5.3, as applicable shall not apply to Licensed Compounds Directed to such Selected Target; (B) if the EPIZYME Pre-IND Opt-Out or EPIZYME Post-EOP1 Clinical Opt-Out in accordance with clause (iii) of Section 2.5.1 was exercised with
respect to [**], milestone (6) for [**] Directed to [**] as set forth in Section 6.5.1 shall, if achieved, be payable by CELGENE to EPIZYME as set forth in Section 6.5.1; (C) the sales milestone payment of Section 6.5.6
shall not apply to the applicable Licensed Products Directed to such Selected Target, and the sales milestone payment of Section 6.5.5 shall be reduced by [**] percent ([**]%); and (D) CELGENE shall pay EPIZYME [**] percent ([**]%) of the
otherwise applicable royalties payable under Section 6.6.1(a) or 6.6.1(b), as applicable, on Net Sales of Licensed Products Directed to such Selected Target. All other economic terms, including CELGENE’s obligation to pay EPIZYME for the
achievement of Development milestones [**] pursuant to Section 6.5.1, and for Development milestones [**] pursuant to Section 6.5.3, as applicable, shall remain applicable to such Selected Target and Licensed Compounds and Licensed
Products Directed thereto. Notwithstanding the foregoing, no rights with respect to the United States shall be transferred by EPIZYME to CELGENE until receipt of all applicable consents and approvals under Antitrust Laws, including the termination
or expiration of any applicable waiting periods under the HSR Act pursuant to Section 2.7.2. 
 (b) In addition, if EPIZYME exercises
an EPIZYME Pre-IND Opt-Out or EPIZYME Post-EOP1 Clinical Opt-Out in accordance with clause (iii) of Section 2.5.1, and CELGENE has elected pursuant to Section 2.4.2(a) to continue research and/or Development of an applicable Available
Target and Compounds, Licensed Compounds and Licensed Products Directed thereto, the following shall apply: 
 (i) Diligence
Obligations. Notwithstanding anything to the contrary in this Agreement, CELGENE shall be required to use Commercially Reasonable Efforts with respect to the research, Development, Manufacturing and Commercialization of the applicable Available
Target, Licensed Compounds and Licensed Products; provided that, if CELGENE incurs at least an aggregate amount of [**] Dollars ($[**]) with respect to such research, Development, Manufacturing and Commercialization of the applicable Available
Target during the [**] year period commencing on such election by CELGENE pursuant to Section 2.4.2(a) to continue research and/or Development after EPIZYME’s exercise of the Pre-IND Opt-Out, then CELGENE shall be deemed to have satisfied
its obligations under this Section 2.4.2(b)(i) for such [**] year period. 

  
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 (ii) Research License. 

(1) Within [**] days of CELGENE’s request, EPIZYME shall disclose to CELGENE (through the JRC) [**] Compounds [**] Controlled by EPIZYME
or its Affiliates that, in EPIZYME’s reasonable judgment, most fully satisfy the Lead Candidate Criteria and/or the Development Candidate Selection Criteria (or such lesser number as has been identified by EPIZYME at such time), together with a
table setting forth in reasonable detail whether, and to what extent, such Compounds meet the Lead Candidate Criteria and/or the Development Candidate Selection Criteria, as applicable. Subject to clause (5) below, CELGENE shall then have the
right to select up to [**] of such Compounds, including up to [**] of such [**], for which EPIZYME shall provide a technology and materials transfer, as set forth in clause (2) below. 

(2) Within [**] days following CELGENE’s selection of Compounds pursuant to clause (1) above, EPIZYME shall perform a technology
and materials transfer and provide to CELGENE the following: (i) Chemistry IP Controlled by EPIZYME or its Affiliates pertaining to such Compounds, that would be useful to identify, synthesize and discover Licensed Compounds Directed to such
Selected Target, and all methods related thereto, and (ii) all assays used by EPIZYME to screen such Compounds for such Selected Target, including all reagents and protocols related thereto, and identification of any Third Party utilized by
EPIZYME to perform such assays (collectively, “EPIZYME Research Tools”). Such technology and materials transfer shall be conducted in a manner sufficient to provide CELGENE or its Third Party subcontractors the ability to reproduce
and perform such assays and reported potencies of such Compounds, and if CELGENE or such subcontractors cannot reproduce results expected from such assays, then EPIZYME agrees to provide such assistance as is reasonably necessary to remedy such
issues; 
 (3) EPIZYME shall grant, and hereby grants, to CELGENE an exclusive, royalty-free, worldwide right and license (the
“Research License”), with the right to sublicense to Subcontractors pursuant to Section 2.11, to use the EPIZYME Research Tools through the completion of a Phase 1 Clinical Trial (it being understood that if CELGENE continues
Development of Compounds, Licensed Compounds and Licensed Products Directed to such Selected Target beyond the completion of a Phase 1 Clinical Trial, the license set forth in Section 5.1.3 and not the license set forth in this
Section 2.4.2(b)((ii)(3) shall cover CELGENE’s use of such EPIZYME Research Tools), solely to continue research and/or Development of such Selected Target and Compounds, Licensed Compounds and Licensed Products Directed thereto, pursuant
to the terms of this Agreement; 
 (4) notwithstanding anything to the contrary in this Agreement, all Know-How that is discovered,
developed, invented, conceived or reduced to practice by or on behalf of CELGENE or its Affiliates or Sublicensees in the exercise of the Research License, and any Patents Covering such Know-How, shall be solely and exclusively owned by CELGENE and
shall not be considered Collaboration IP for any purpose under this Agreement nor included in any of the licenses granted to EPIZYME under this Agreement; and 

(5) in addition to the Compounds selected by CELGENE pursuant to clause (1) above, CELGENE may select from among the Compounds disclosed
by EPIZYME pursuant to clause (1) above additional Compounds as to which CELGENE desires EPIZYME to provide a technology and materials transfer pursuant to clause (2) above. CELGENE shall be responsible for reimbursing EPIZYME for all
internal and out-of-pocket costs reasonably incurred by EPIZYME in providing such technology and materials transfer for such additional Compounds in accordance with a budget to be mutually agreed upon in writing by the Parties. 

  
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 (iii) EPIZYME Research Services. Upon CELGENE’s request and the mutual written
agreement of the Parties, EPIZYME would provide services to CELGENE to identify, discover, synthesize and optimize Compounds Directed to such Selected Target. If the Parties mutually agree that EPIZYME will provide such services, the Parties shall
negotiate a research plan to define the scope of such services, and CELGENE would be responsible for reimbursing EPIZYME for all internal costs and out-of-pocket costs reasonably incurred by EPIZYME in providing such services. For clarity, EPIZYME
shall not be obligated to provide any such services, nor shall CELGENE be obligated to retain EPIZYME to provide such services, except as the Parties may mutually agree in writing in their respective sole discretion. 

(iv) EPIZYME Opt-In. CELGENE may offer, in its sole discretion, to EPIZYME the right for EPIZYME to opt-back in to, and participate
in, the research and Development of Compound(s) Directed to such Selected Target. If CELGENE wishes to make such offer, CELGENE will provide to EPIZYME reasonable information demonstrating CELGENE’s hypothesis that further research and
development of Compounds Directed to such Selected Target is scientifically warranted. If the Parties mutually agree in writing that EPIZYME will opt-back in to such research and Development, and subject to the terms of such written agreement,
(1) EPIZYME shall resume all of its responsibilities and activities under this Agreement with respect to Compounds directed to such Selected Target as if EPIZYME had not exercised the EPIZYME Pre-IND Opt-Out, (2) Section 2.4.2(a)
shall cease to apply, provided that (i) CELGENE shall not be required to pay Development milestone payments, as set forth in Section 6.5.1 and 6.5.3, that have been achieved prior to the date that EPIZYME opts-back in, and
(ii) if the Development milestone [**] in Section 6.5.1 or 6.5.3 becomes payable, the amount of such [**] shall be reduced by [**] dollars ($[**]), (3) EPIZYME shall be obligated to Develop, at its sole cost and expense, any
Development Candidates directed to such Selected Target through the completion of Phase 1 Clinical Trials and deliver to CELGENE the IND Data Package (if the IND is filed by EPIZYME) and the Phase 1 Data Package, and (4) CELGENE shall be
required to exercise its IND Option (if the IND is filed by EPIZYME and has not, prior to EPIZYME’s opt-back in, been filed by or on behalf of CELGENE) and Phase 1 Option pursuant to the terms of this Agreement in order to obtain the rights
associated therewith. For clarity, CELGENE shall not be required to offer to EPIZYME any right to opt-back in to, or participate in, the research and Development of Compound(s) Directed to such Selected Target


  
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after an EPIZYME Pre-IND Opt-Out or an EPIZYME Post-EOP1 Clinical Opt-Out in accordance with clause (iii) of Section 2.5.1, nor shall EPIZYME be required to accept any such offer from
CELGENE, except as the Parties may mutually agree in writing. 
 (v) Other Effects of Opt-Out. Subject to Section 2.4(b)(iv),
the provisions of Sections 2.6.2(e), (f), (h), (j), (k) and (m) shall apply, mutatis mutandis, and if CELGENE elects, in its sole discretion, after the completion of a Phase 1 Clinical Trial for a Development Candidate Directed to
such Available Target, to continue the research, Development, Manufacturing and Commercialization of the applicable Available Target and Compounds, Licensed Compounds and Licensed Products Directed to such Available Target, then the provisions of
Sections 2.6.2(i), (l), (n) and (o) also shall apply, mutatis mutandis. 
 2.5 EPIZYME Post-EOP1 Clinical Opt-Out. 

2.5.1 Notice of EPIZYME Post-EOP1 Clinical Opt-Out. As to Shared Development Programs, clauses (i) and (ii) below shall apply
on a Shared Development Program-by-Shared Development Program basis and, to the extent provided in clause (iii) below, as to Available Targets for which EPIZYME is responsible for conducting a Phase 1 Clinical Trial prior to CELGENE’s
exercise of the Phase 1 Option, clause (iii) below shall apply on a Phase 1 Clinical Trial-by-Phase 1 Clinical Trial basis, (i) if EPIZYME reasonably determines to discontinue a Phase 1 Clinical Trial or a Phase 2 Clinical Trial in a
Shared Development Program because the Development Program Stopping Rules specified for such Clinical Trial in the applicable clinical trial protocol therefor require that such Clinical Trial be stopped, and only in accordance with Applicable Law
and after all necessary communications with the applicable Regulatory Authorities have occurred, or (ii) if EPIZYME determines in its sole discretion, after the completion of a Phase 1 Clinical Trial or a Phase 2 Clinical Trial for a
Development Candidate Directed to a Selected Target in a Shared Development Program, that the Development Program Stopping Rules have been satisfied with respect to such Available Target, or (iii) if during the conduct of a Phase 1 Clinical
Trial prior to CELGENE’s exercise of the Phase 1 Option, the Development Program Stopping Rules set forth in the protocol for such Phase 1 Clinical Trial require that such Phase 1 Clinical Trial be stopped, EPIZYME shall, after discussing the
matter within the JDC, have the right, in its sole discretion, to exercise an opt-out as to the applicable Shared Development Program or pre-Phase 1 Option exercise program, as applicable (“EPIZYME Post-EOP1 Clinical Opt-Out”),
pursuant to which EPIZYME shall have no further obligation to participate in any Development with respect to the applicable Available Target(s). EPIZYME may exercise the EPIZYME Post-EOP1 Clinical Opt-Out by providing written notice to CELGENE of
such election within [**] days after the completion or discontinuation of the Phase 1 Clinical Trial or Phase 2 Clinical Trial, as applicable, which opt-out shall take effect [**] days after the date of such written notice (the “EPIZYME
Post-EOP1 Clinical Opt-Out Date”). Notwithstanding the foregoing, no rights with respect to the United States shall be transferred by EPIZYME to CELGENE until receipt of all applicable consents and approvals under Antitrust Laws, including
the termination or expiration of any applicable waiting periods under the HSR Act pursuant to Section 2.7.2. If EPIZYME exercises such EPIZYME Post-EOP1 Clinical Opt-Out based on the conditions specified in clause (iii) above, EPIZYME
shall be responsible for appropriately winding down such Phase 1 Clinical Trial and 

  
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the consequences set forth in Section 2.4.2 and not the consequences set forth in Section 2.5.2 shall apply to such EPIZYME Post-EOP1 Clinical Opt-Out as if such EPIZYME Post-EOP1
Clinical Opt-Out were an EPIZYME Pre-IND Opt-Out. 
 2.5.2 Effect of EPIZYME Post-EOP1 Clinical Opt-Out. In the event EPIZYME
exercises the EPIZYME Post-EOP1 Clinical Opt-Out with respect to a Shared Development Program and CELGENE wishes to continue Development of the applicable Selected Target and Licensed Compounds and Licensed Products Directed thereto, CELGENE may
elect to do so at its sole cost and expense within [**] days after EPIZYME’s exercise of the applicable EPIZYME Post-EOP1 Clinical Opt-Out, which election CELGENE shall promptly notice to EPIZYME in writing within such [**] day period, and upon
such election by CELGENE the CELGENE Territory shall be expanded to include the United States, the license under Section 5.1.3 shall automatically be deemed granted with respect to Compounds, Licensed Compounds and Licensed Products Directed to
such Selected Target, and the provisions of Section 2.6.2 other than Section 2.6.2(g) shall apply, mutatis mutandis. Subject to Section 2.7.2(c), in addition to the royalties payable by CELGENE to EPIZYME with respect to Net
Sales in the CELGENE Territory (excluding the United States)), CELGENE shall pay EPIZYME the royalties on Net Sales by CELGENE, its Affiliates and Sublicensees in the United States, on a Licensed Product-by-Licensed Product basis, such that:
(i) if the Selected Target is DOT1L, the royalty provisions of Section 6.6.1(c)(ii) shall apply; and (ii) if the Selected Target is [**], the royalty provisions of Section 6.6.1(a)(ii) shall apply, provided that in each
case such royalties shall be reduced by [**] percent ([**]%) of the otherwise applicable royalties payable under Section 6.6.1(a) or 6.6.1(c). Further, if such Selected Target is [**], milestone [**] for [**] Directed to [**] shall, if
achieved, be payable by CELGENE to EPIZYME as set forth in Sections 6.5.1, and if such Selected Target is DOT1L, [**] shall not apply to the applicable Licensed Products Directed to such Selected Target. Notwithstanding the foregoing, no rights with
respect to the United States shall be transferred by EPIZYME to CELGENE until receipt of all applicable consents and approvals under Antitrust Laws, including the termination or expiration of any applicable waiting periods under the HSR Act pursuant
to Section 2.7.2. 
 2.6 EPIZYME Late Stage Opt-Out. 

2.6.1 Notice of Opt-Out. On a Selected Target-by-Selected Target basis with respect to Shared Development Programs, EPIZYME shall have
the right, in its sole discretion, to elect to exercise an “EPIZYME Late Stage Opt-Out”, pursuant to which EPIZYME opts-out of further participation in: 

(a) Development with respect to the applicable Shared Development Program, such EPIZYME Late Stage Opt-Out to be exercised only at any time
between [**] days prior to and [**] days prior to either the (i) scheduled Initiation of the first Pivotal Clinical Trial (such period, the “Pre-Pivotal Opt-Out Period”), or (ii) estimated date of filing of the first NDA
(such period, the “Pre-NDA Opt-Out Period”; and together with the Pre-Pivotal Opt-Out Period, the “Pre-Regulatory Approval Opt-Out Period”); or 

(b) Commercialization at any time after the first Regulatory Approval by the FDA of a Licensed Compound or Licensed Product from the
applicable Shared Development Program (the “Post-Regulatory Approval Opt-Out Period”); 

  
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 in each case by providing written notice to CELGENE of such election. Any such EPIZYME Late Stage Opt-Out shall,
subject to Section 2.6.4, take effect [**] days after the date of such written notice (the “EPIZYME Late Stage Opt-Out Date”). For purposes of clarity, no rights with respect to the United States shall be transferred by EPIZYME
to CELGENE until receipt of all applicable consents and approvals under Antitrust Laws, including the termination or expiration of any applicable waiting periods under the HSR Act pursuant to Section 2.7.2. Subject to Sections 2.6.2(c),
2.6.2(d), 2.6.3(a) and 2.6.3(b), EPIZYME shall not be responsible for Global Development Costs regarding the applicable Shared Development Program incurred after the EPIZYME Late Stage Opt-Out Date. 

2.6.2 Effect of Pre-Regulatory Approval Opt-Out. In the event EPIZYME exercises the EPIZYME Late Stage Opt-Out during the
Pre-Regulatory Approval Opt-Out Period, the following shall apply: 
 (a) each Party shall provide the other Party with a reasonably
detailed accounting of all Global Development Costs incurred by such Party with respect to such Shared Development Program within [**] days after the EPIZYME Late Stage Opt-Out Date; 

(b) EPIZYME and CELGENE shall continue to share Global Development Costs in accordance with the applicable budget under Section 6.3
through the EPIZYME Late Stage Opt-Out Date, including any Global Development Costs that are incurred through and including the EPIZYME Late Stage Opt-Out Date, even if payment of such Development Cost is not invoiced or paid until after the EPIZYME
Late Stage Opt-Out Date; 
 (c) with respect to any ongoing Clinical Trials with respect to such Shared Development Program
(i) conducted as part of the Collaboration under the applicable Development Plan and for which Global Development Costs are incurred, or (ii) related solely to the EPIZYME Territory, for which CELGENE has not notified EPIZYME prior to the
EPIZYME Late Stage Opt-Out Date that it wishes to assume responsibility, EPIZYME shall continue to conduct any ongoing Clinical Trials, subject to Section 2.12.1, with respect to such Shared Development Program only with regard to those
patients enrolled at the date of the EPIZYME Late Stage Opt-Out Date and may otherwise cease enrollment and cancel all cancelable expenses relating to such Clinical Trials in accordance with applicable Laws, and, in the case of (i), all Development
Costs incurred in the conduct of such Clinical Trials shall constitute Global Development Costs to be borne fifty percent (50%) by EPIZYME and fifty percent (50%) by CELGENE, even if payment of such Development Cost is not invoiced or paid
until after the EPIZYME Late Stage Opt-Out Date, and in the case of (ii), all Development Costs incurred in the conduct of such Clinical Trials shall be borne one hundred percent (100%) by EPIZYME; it being understood and agreed that following
an EPIZYME Late Stage Opt-Out, in the event of a data lock in such Clinical Trial, upon CELGENE’s request, EPIZYME will cooperate with CELGENE as may be reasonably necessary to enable CELGENE to prepare and complete any and all databases, files
and reports in the form required for submission to the Regulatory Authorities; 

  
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 (d) with respect to any ongoing Clinical Trials with respect to such Shared Development Program
(i) conducted as part of the Collaboration under the applicable Development Plan and for which Global Development Costs are incurred, or (ii) related solely to the EPIZYME Territory, for which CELGENE has notified EPIZYME prior to the
EPIZYME Late Stage Opt-Out Date that it wishes to assume responsibility, in each case, (1) each Party shall cooperate with the other Party to facilitate the orderly transfer to CELGENE of the conduct of such Clinical Trials as soon as
reasonably practicable after the EPIZYME Late Stage Opt-Out Date, or, in the event CELGENE is not able to obtain all applicable consents and approvals under Antitrust Laws, to wind down such Clinical Trial, (2) until such time as the conduct of
such Clinical Trials has been successfully transferred to CELGENE or completely wound down, EPIZYME shall continue to conduct such Clinical Trials, subject to Section 2.12.1, or to wind down such Clinical Trial, (3) between the EPIZYME
Late Stage Opt-Out Date and the date on which the conduct of such Clinical Trials has been successfully transferred to CELGENE or on which such Clinical Trial has been successfully wound down, all Development Costs incurred in the conduct or
winding-down of such Clinical Trials shall constitute Global Development Costs to be borne fifty percent (50%) by EPIZYME and fifty percent (50%) by CELGENE, even if payment of such Development Cost is not invoiced or paid until after the
EPIZYME Late Stage Opt-Out Date; it being understood and agreed that following an EPIZYME Late Stage Opt-Out, in the event of a data lock in such Clinical Trial, upon CELGENE’s request, EPIZYME will cooperate with CELGENE as may be reasonably
necessary to enable CELGENE to prepare and complete any and all databases, files and reports in the form required for submission to the Regulatory Authorities; 

(e) EPIZYME shall provide to CELGENE a summary report of the status and results of its (and its Affiliates’ and Sublicensees’)
material research, Development, Manufacturing and Commercialization activities in connection with such Shared Development Program prior to the EPIZYME Late Stage Opt-Out Date within [**] days after the EPIZYME Late Stage Opt-Out Date; 

(f) without limiting the generality of the remainder of this Section 2.6.2, EPIZYME shall use its Commercially Reasonable Efforts, at no
cost to CELGENE, to effect a seamless, timely transition to CELGENE of all research, Development, Manufacturing and Commercialization activities and responsibilities with respect to such Shared Development Program in accordance with a transition
plan to be mutually agreed by the Parties; 
 (g) subject to Section 2.7.2(c), the royalty provisions of Sections 6.6.1(a)(ii) and
6.6.1(c)(ii) shall apply to the Licensed Products within such Shared Development Program, without any retroactive application of such provisions; 

(h) the licenses granted by CELGENE to EPIZYME under Sections 5.2.2, 5.2.3(a), and 5.2.4 with respect to Licensed Compounds, Licensed
Products and related Diagnostic Products, as applicable, within such Shared Development Program shall terminate as of the EPIZYME Late Stage Opt-Out Date; 

  
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 (i) subject to Section 2.7.2(c), EPIZYME shall and hereby does grant to CELGENE commencing
upon the EPIZYME Late Stage Opt-Out Date and continuing during the remainder of the Term, an exclusive right and license (even as to EPIZYME and its Affiliates) in the Field in the EPIZYME Territory, with the right to grant sublicenses (subject to
Section 5.1.6), under the EPIZYME IP and EPIZYME’s interest in the Joint Collaboration IP, to research, Develop, Manufacture, have Manufactured, use, offer for sale, sell, import and otherwise Commercialize Licensed Compounds, Licensed
Products and related Diagnostic Products within such Shared Development Program; 
 (j) subject to Section 2.7.2(c), the CELGENE
Territory with respect to such Shared Development Program shall expand to include the EPIZYME Territory (including the United States); 

(k) CELGENE shall have sole responsibility and decision-making authority over all research, Development, Manufacturing and Commercialization
activities in connection with the applicable Shared Development Program, which shall no longer be within the purview of the JDC (and in the event EPIZYME has opted-out of all Shared Development Programs, the JDC shall be disbanded); 

(l) CELGENE shall be required to use Commercially Reasonable Efforts with respect to the research, Development, Manufacturing and
Commercialization of the applicable Selected Target, Licensed Compounds and Licensed Products; provided that, if CELGENE incurs at least an aggregate amount of [**] Dollars ($[**]) with respect to such research, Development, Manufacturing and
Commercialization of the applicable Selected Target during the [**] year period commencing on the EPIZYME Late Stage Opt-Out Date, then CELGENE shall be deemed to have satisfied its obligations under this Section 2.6.2(l) for such [**] year
period; 
 (m) the Parties’ exclusivity obligations with respect to such Selected Target under Section 7.1 shall survive; 

(n) subject to Section 2.7.2(c), EPIZYME shall grant CELGENE the rights and fulfill the obligations set forth in Sections 12.6.1(f) -
12.6.1(m), inclusive, with respect to the Selected Target, Licensed Compounds, Licensed Products and related Diagnostic Products in such Shared Development Program. Subject to Section 2.7.2(c), EPIZYME shall reasonably cooperate with CELGENE
with respect to the foregoing activities set forth in this Section 2.6.2; and in Sections 12.6.1(f) – 12.6.1(m), inclusive, with all references in such Sections to “CELGENE” replaced by “EPIZYME,” all references in such
Sections to “EPIZYME” replaced by “CELGENE,” all references in such Sections to “Terminated Products” replaced by “Licensed Compounds,” “Licensed Products,” and/or “related Diagnostic
Products,” as applicable, and all references in such Sections to “Terminated Country(ies)” replaced by “EPIZYME Territory,” and any other changes as the context requires; and 

  
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 (o) the milestone table set forth in Section 6.5.2 shall be modified to read as follows:

  

					
	 Milestone Event (For DOT1L)
	  	Milestone
Payments
(in $ [**])	 
	 [**]
	  	 	[**	] 
	 [**]
	  	 	[**	] 
	 [**]
	  	 	[**	] 
	 [**]
	  	 	[**	] 
	 [**]
	  	 	[**	] 
	 [**]
	  	 	[**	] 

 For purposes of clarity, except as provided in Sections 2.6.2(c) and (d) above, after the EPIZYME Late Stage Opt-Out
Date, CELGENE shall be responsible for all Development Costs for such Shared Development Program and the applicable Selected Target and EPIZYME shall not be entitled to perform any Development, Manufacturing or Commercialization activities with
respect to such Shared Development Program and Selected Target, and EPIZYME shall not have any option or right to buy-back the license and rights granted to CELGENE in Section 2.6.2, which shall continue for the remainder of the Term. 

2.6.3 Effect of Post-Regulatory Approval Opt-Out. In the event EPIZYME exercises the EPIZYME Late Stage Opt-Out during the
Post-Regulatory Approval Opt-Out Period to CELGENE, the following shall apply: 
 (a) with respect to any ongoing Clinical Trials of the
applicable Licensed Products (i) conducted as part of the Collaboration under the applicable Development Plan and for which Global Development Costs are incurred, or (ii) related solely to the EPIZYME Territory, for which CELGENE has not
notified EPIZYME prior to the EPIZYME Late Stage Opt-Out Date that it wishes to assume responsibility, EPIZYME shall continue to conduct any ongoing Clinical Trials, subject to Section 2.12.1, with respect to such Licensed Products only with
regard to those patients enrolled at the date of the EPIZYME Late Stage Opt-Out Date and may otherwise cease enrollment and cancel all cancelable expenses relating to such Clinical Trials in accordance with applicable Laws, and, in the case of (i),
all Development Costs incurred in the conduct of such Clinical Trials shall constitute Global Development Costs to be borne fifty percent (50%) by EPIZYME and fifty percent (50%) by CELGENE, even if payment of such Development Cost is not
invoiced or paid until after the EPIZYME Late Stage Opt-Out Date, and in the case of (ii), all Development Costs incurred in the conduct of such Clinical Trials shall be borne [**] percent ([**]%) by EPIZYME; it being understood and agreed that
following an EPIZYME Late Stage Opt-Out, in the event of a data lock in such Clinical Trial, upon CELGENE’s request, EPIZYME will cooperate with CELGENE as may be reasonably necessary to enable CELGENE to prepare and complete any and all
databases, files and reports in the form required for submission to the Regulatory Authorities; 

  
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 (b) with respect to any ongoing Clinical Trials of the applicable Licensed Products
(i) conducted as part of the Collaboration under the applicable Development Plan and for which Global Development Costs are incurred, or (ii) related solely to the EPIZYME Territory, for which CELGENE has notified EPIZYME prior to the
EPIZYME Late Stage Opt-Out Date that it wishes to assume responsibility, in each case, (1) each Party shall cooperate with the other Party to facilitate the orderly transfer to CELGENE of the conduct of such Clinical Trials as soon as
reasonably practicable after the EPIZYME Late Stage Opt-Out Date, or, in the event CELGENE is not able to obtain all applicable consents and approvals under Antitrust Laws, to wind down such Clinical Trial, (2) until such time as the conduct of
such Clinical Trials has been successfully transferred to CELGENE or completely wound down, EPIZYME shall continue to conduct such Clinical Trials, subject to Section 2.12.1, or to wind down such Clinical Trial, (3) between the EPIZYME
Late Stage Opt-Out Date and the date on which the conduct or winding-down of such Clinical Trials has been successfully transferred to CELGENE or on which such Clinical Trial has been successfully wound down, all costs incurred in the conduct of
such Clinical Trials shall be borne fifty percent (50%) by EPIZYME and fifty percent (50%) by CELGENE, even if payment of such cost is not invoiced or paid until after the EPIZYME Late Stage Opt-Out Date; it being understood and agreed
that following an EPIZYME Late Stage Opt-Out, in the event of a data lock in such Clinical Trial, upon CELGENE’s request, EPIZYME will cooperate with CELGENE as may be reasonably necessary to enable CELGENE to prepare and complete any and all
databases, files and reports in the form required for submission to the Regulatory Authorities; 
 (c) EPIZYME shall provide to CELGENE a
summary report of the status and results of its (and its Affiliates’ and Sublicensees’) material Development, Manufacturing and Commercialization activities in connection with such Licensed Compounds, Licensed Products and related
Diagnostic Products prior to the opt-out within [**] days after such opt-out; 
 (d) without limiting the generality of the remainder of
this Section 2.6.3, EPIZYME shall use its Commercially Reasonable Efforts, at no cost to CELGENE, to effect a seamless, timely transition to CELGENE of all Development, Manufacturing and Commercialization activities and responsibilities with
respect to such Licensed Compound, Licensed Product and related Diagnostic Products in accordance with a transition plan to be mutually agreed by the Parties; 

(e) subject to Section 2.7.2(c), the royalty provisions of Sections 6.6.1(a)(ii) and 6.6.1(c)(ii) shall apply to such Licensed Products;

 (f) the licenses granted by CELGENE to EPIZYME under Sections 5.2.2, 5.2.3(a), and 5.2.4 with respect to the applicable Licensed
Compounds, Licensed Products and Diagnostic Products shall terminate as of the EPIZYME Late Stage Opt-Out Date; 

  
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 (g) subject to Section 2.7.2(c), EPIZYME shall and hereby does grant to CELGENE commencing
upon the EPIZYME Late Stage Opt-Out Date and continuing during the remainder of the Term, an exclusive right and license (even as to EPIZYME and its Affiliates) in the Field in the EPIZYME Territory, with the right to grant sublicenses (subject to
Section 5.1.6), under the EPIZYME IP and EPIZYME’s interest in the Joint Collaboration IP, to Manufacture, have Manufactured, use, offer for sale, sell, import and otherwise Commercialize the applicable Licensed Compounds, Licensed
Products and Diagnostic Products; 
 (h) subject to Section 2.7.2(c), the CELGENE Territory with respect to such Shared Development
Program shall expand to include the United States and any Terminated Country(ies); 
 (i) CELGENE shall have sole responsibility and
decision-making authority over all Development, Manufacturing and Commercialization activities in connection with the applicable Licensed Compounds, Licensed Products and Diagnostic Products; 

(j) CELGENE shall be required to use Commercially Reasonable Efforts with respect to the Development, Manufacturing and Commercialization of
the applicable Licensed Compounds and Licensed Products; provided that, if CELGENE incurs at least an aggregate amount of [**] Dollars ($[**]) with respect to such research, Development, Manufacturing and Commercialization of the applicable Selected
Target during the [**] year period commencing on the EPIZYME Late Stage Opt-Out Date, then CELGENE shall be deemed to have satisfied its obligations under this Section 2.6.3(j) for such [**] year period; 

(k) the Parties’ exclusivity obligations with respect to such Selected Target under Section 7.1 shall survive; and 

(l) subject to Section 2.7.2(c), EPIZYME shall grant CELGENE the rights and fulfill the obligations set forth in Sections 12.6.1(f) -
12.6.1(m), inclusive, with respect to the Selected Target, Licensed Compounds, Licensed Products and related Diagnostic Products in such Shared Development Program. Subject to Section 2.7.2(c), EPIZYME shall reasonably cooperate with CELGENE
with respect to the foregoing activities set forth in this Section 2.6.3; and in Sections 12.6.1(f) – 12.6.1(m), inclusive, with all references in such Sections to “CELGENE” replaced by “EPIZYME,” all references in such
Sections to “EPIZYME” replaced by “CELGENE,” all references in such Sections to “Terminated Products” replaced by “Licensed Compounds,” “Licensed Products,” and/or “related Diagnostic
Products,” as applicable, and all references in such Sections to “Terminated Country(ies)” replaced by “EPIZYME Territory,” and any other changes as the context requires. 

For purposes of clarity, except as provided in Sections 2.6.3(a) and (b), after the EPIZYME Late Stage Opt-Out Date, CELGENE shall be responsible for all
costs and expenses with respect to the Development, Manufacture and Commercialization of the applicable Selected Target, Licensed Compounds, Licensed Products and related Diagnostic Products and EPIZYME shall not be entitled to perform any
Development, Manufacturing or Commercialization activities with respect to such Selected Target, Licensed Compound, Licensed Product and Diagnostic Products, and EPIZYME shall not have any option or right to buy-back the license and rights granted
to CELGENE in Section 2.6.3, which shall continue for the remainder of the Term. 

  
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 2.6.4 Termination. Notwithstanding anything in this Section 2.6 to the contrary,
EPIZYME’s exercise of its EPIZYME Late Stage Opt-Out shall not take effect if, prior to the EPIZYME Late Stage Opt-Out Date, CELGENE provides written notice to EPIZYME of CELGENE’s decision to terminate the Agreement as to the applicable
Selected Target pursuant to Section 12.2.2, in which case the provisions of Section 12.6.1 shall apply to such termination. 
 2.7
Data Transfer; HSR Approval. 
 2.7.1 Data Transfer. Within [**] days after the opt-out date applicable to CELGENE’s
exercise of an EPIZYME Pre-IND Opt-Out pursuant to Section 2.4, an EPIZYME Post-EOP1 Clinical Opt-Out pursuant to Section 2.5 or an EPIZYME Late Stage Opt-Out pursuant to Section 2.6 (i.e., the EPIZYME Pre-IND Opt-Out Date, the
EPIZYME Post-EOP1 Clinical Opt-Out Date or the EPIZYME Late Stage Opt-Out Date, as applicable), EPIZYME shall provide to CELGENE, on an Available Target-by-Available Target basis (or Selected Target-by-Selected Target basis, as applicable) at no
cost to CELGENE, a data package containing a reasonably detailed summary of any material research and/or development activities conducted with respect to any Licensed Compound(s) directed to such Available Target or Selected Target, as applicable,
including any material data generated in connection therewith, to the extent such data is in EPIZYME’s or its Third Party service providers’ possession at the time of the applicable opt-out date. 

2.7.2 HSR Approval. 

(a) Subject to the terms and conditions of this Agreement (including Section 2.6.4), each of the Parties will use its Commercially
Reasonable Efforts to take, or cause to be taken, all actions and to do, or cause to be done, all things necessary, proper or advisable under Antitrust Laws to consummate (a) an EPIZYME Pre-IND Opt-Out, an EPIZYME Post-EOP1 Clinical Opt-Out or
an EPIZYME Late Stage Opt-Out, as applicable, as soon as practicable after any applicable written notice by EPIZYME of such opt-out, or (b) CELGENE’s exercise of the Phase 1 Option with respect to [**] and/or [**] (either of (a) or
(b), a “US Rights Event”), including (in each case of (a) and (b)) (i) preparing and filing, in consultation with the other Party and as promptly as practicable and advisable after the date of receipt by CELGENE of a
written notice of the applicable US Rights Event, all documentation to effect all necessary applications, notices, petitions, filings, requests and other documents and to obtain as promptly as practicable all consents, clearances, waivers, licenses,
orders, registrations, approvals, permits, rulings and authorizations necessary to be obtained from any Third Party and/or any applicable governmental authority in order to consummate such US Rights Event, as applicable, and (ii) taking all
reasonable steps as may be necessary to obtain all such material consents, clearances, waivers, licenses, orders, registrations, approvals, permits, rulings and authorizations. 

(b) In furtherance and not in limitation of the foregoing but subject to this Section 2.7, each Party hereto agrees (i) to make or
cause to be made, in consultation and cooperation with the other Party and as promptly as practicable and advisable, but no later than 

  
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[**] days, after the date of written notice by EPIZYME of such US Rights Event, any necessary filing of a Notification and Report Form pursuant to the HSR Act and all other necessary
registrations, declarations, notices and filings relating to such US Rights Event, with other applicable governmental authorities under Antitrust Laws, (ii) to respond as promptly as practicable to any inquiries received and supply as promptly
as practicable any additional information and documentary material that may be requested pursuant to the HSR Act and any other Antitrust Laws, (iii) to take all other actions, if any, reasonably necessary to cause the expiration or termination
of the applicable waiting periods under the HSR Act and any other Antitrust Laws as soon as practicable, and (iv) not to enter into any agreement with any applicable governmental authority to extend any waiting period under the HSR Act or any
other Antitrust Laws without the prior written consent of CELGENE. 
 (c) Notwithstanding anything to the contrary in this Agreement,
CELGENE shall not be required to sell, divest, hold separate, license or agree to any other structural or conduct remedy with respect to, any operations, divisions, businesses, product lines, customers, assets or relationships of CELGENE or any of
its Affiliates. In the event any of the foregoing is required by the applicable governmental authority in order to consummate the EPIZYME Pre-IND Opt-Out, EPIZYME Post-EOP1 Clinical Opt-Out or EPIZYME Late Stage Opt-Out, as applicable, CELGENE shall
not be required to engage in such conduct, in which case, (i) the EPIZYME Territory shall no longer include the United States and any Terminated Country(ies), if applicable, (ii) the CELGENE Territory shall not be expanded to include the
United States and any Terminated Country(ies), if applicable, (iii) Sections 2.6.2(o), 6.6.1(a)(ii) and 6.6.1(c)(ii) shall not apply in any event, (iv) subject to Sections 2.5.2, 2.6.2(c) and 2.6.3(a), but notwithstanding Sections 2.6.2(d)
and 2.6.3(b), EPIZYME shall not be responsible for Global Development Costs regarding the applicable Shared Development Program incurred ninety (90) days after the date of the applicable written notice described in Section 2.6.1, and
(v) notwithstanding anything to the contrary, the following provisions shall apply, as applicable: 2.6.2(h), 2.6.2(k), 2.6.2(m), 2.6.3(f), 2.6.3(i), and 2.6.3(k), effective [**] days after the date of the applicable written notice described in
Section 2.6.1. 
 2.8 IND and Phase 1 Development. 

2.8.1 Subject to Section 2.4, during the applicable Selection Term for an Available Target, (a) subject to Section 2.8.3,
EPIZYME shall use Commercially Reasonable Efforts to prepare, file and obtain the effectiveness of an IND in the United States or a Major EU Country for at least one (1) Development Candidate for such Available Target; and (b) if CELGENE
has exercised the IND Option with respect to an Available Target, EPIZYME may initiate, conduct and complete, in its sole discretion, a Phase 1 Clinical Trial for Development Candidate(s) Directed to each such Available Target, subject to
Section 2.3.5; in each case ((a) and (b)), at EPIZYME’s sole cost and expense and in accordance with the Research Plan. If EPIZYME so elects to not initiate, conduct and complete a Phase 1 Clinical Trial, EPIZYME shall provide written
notice thereof to CELGENE prior to the filing of the IND for the applicable Development Candidate. For clarity, if EPIZYME elects not to conduct a Phase 1 Clinical Trial for the applicable Development Candidate Directed to an Available Target,
EPIZYME shall be deemed to have exercised an EPIZYME Pre-IND Opt-Out as to such Available Target pursuant to Section 2.4. 

  
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 2.8.2 Subject to Section 2.3.6, EPIZYME shall keep CELGENE reasonably informed of its
performance of the Research Plan by updating the JRC on a [**] basis with the results of its activities under the Research Plan, including all Compounds, Collaboration IP and Regulatory Materials, for each Available Target during the Option Term.

 2.8.3 Within [**] days after the completion of all IND-enabling studies for a Development Candidate directed to an Available Target,
EPIZYME shall provide to CELGENE, or a Third Party advisor designated by CELGENE, the IND Data Package for such Development Candidate; provided that, as to [**], during any period when CELGENE is engaged in a [**], CELGENE may only elect to have
EPIZYME provide such IND Data Package to a Third Party advisor. If CELGENE designates a Third Party advisor to receive the IND Data Package, such Third Party advisor shall agree to be bound by confidentiality obligations consistent with those set
forth in Article 9 and shall only provide to CELGENE a written report summarizing its conclusions regarding the suitability of such Development Candidate for further Development and Commercialization and shall not provide to CELGENE the IND Data
Package. Upon receipt of the IND Data Package, CELGENE (or its designee) shall have [**] days to review such IND Data Package and CELGENE (or its designee) shall notify EPIZYME within [**] days of receipt of any reasonable additional information and
records related to such Development Candidate that CELGENE desires (such right to request additional information to be limited to a single request within such period), and EPIZYME shall respond to such request within [**] days thereof. If EPIZYME
does not materially provide such requested reasonable additional information to CELGENE (or its designee) within such [**] day period, the IND Option Period with respect to such Available Target shall be extended by a period of time equal to the
number of days after such [**] day period during which EPIZYME fails to materially provide such requested reasonable additional information. To the extent that CELGENE designates a Third Party advisor to receive the IND Data Package, such Third
Party advisor shall, prior to delivering to CELGENE a written report documenting its conclusions, provide a copy thereof to EPIZYME for EPIZYME’s review and comment, which review and comment shall be limited solely to identifying any
inaccuracies in the facts relied upon by the Third Party advisor in making its conclusions and to removing any of EPIZYME’s Confidential Information relating to chemical structure of the Development Candidate; provided that, as to [**], during
any period when CELGENE is engaged in a [**], EPIZYME may also require that the Third Party advisor remove any information from such report that EPIZYME reasonably determines is competitively sensitive. EPIZYME shall not file an IND for a
Development Candidate until the earlier of the expiration of the IND Option Period or CELGENE’s exercise of the IND Option for such Development Candidate, unless otherwise agreed in writing by CELGENE, provided that if CELGENE exercises
the IND Option relating to such Development Candidate, EPIZYME agrees to reasonably delay the filing of the IND for such Development Candidate as requested by CELGENE for the purposes of making any necessary Patent filings with respect to such
Development Candidate. 

  
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 2.8.4 Within [**] days after the completion of a Phase 1 Clinical Trial for a Development
Candidate directed to an Available Target, EPIZYME shall provide to CELGENE, or a Third Party advisor designated by CELGENE, the Phase 1 Data Package for such Development Candidate. If CELGENE designates a Third Party advisor to receive the Phase 1
Data Package, such Third Party advisor shall agree to be bound by confidentiality obligations consistent with those set forth in Article 9. Upon receipt of the Phase 1 Data Package, CELGENE (or its designee) shall have [**] days to review such Phase
1 Data Package and CELGENE (or its designee) shall notify EPIZYME within [**] days of receipt of any reasonable additional information and records related to such Development Candidate and/or Phase 1 Clinical Trial that CELGENE desires (such right
to request additional information to be limited to a single request within such period), and EPIZYME shall respond to such request within [**] days thereof. If EPIZYME does not materially provide such requested additional information to CELGENE (or
its designee) within such [**] day period, the End of Phase 1 Date with respect to such Available Target shall be extended by a period of time equal to the number of days after such [**] day period during which EPIZYME fails to materially provide
such requested additional information. 
 2.8.5 CELGENE shall have the right, in its sole discretion, to terminate all Research Plan
activities with respect to any or all Available Targets at any time after one (1) year after the Effective Date upon [**] months written notice to EPIZYME. Upon such termination by CELGENE with respect to an Available Target, (i) the Phase
1 Option shall expire with respect to such Available Target, (ii) such Available Target shall be deemed a Lapsed Target, and (iii) such Lapsed Target shall no longer be an Available Target. For avoidance of doubt, termination by CELGENE of
Research Plan activities with respect to an Available Target shall not terminate or otherwise affect Research Plan activities with respect to any other Available Target. 

2.9 Options; Target Selection. 

2.9.1 IND Option. On an Available Target-by-Available Target basis, CELGENE shall have the exclusive right, exercisable at
CELGENE’s sole discretion, to obtain the exclusive license set forth in Section 5.1.2 with respect to such Available Target (the “IND Option”), by providing to EPIZYME written notice of exercise of such IND Option with
respect to such Available Target (“IND Notice of Exercise”) during the applicable IND Option Period, or as otherwise provided in Section 2.4. Following any such IND Notice of Exercise by CELGENE, except as provided in
Section 2.4, (a) after effectiveness of the applicable IND in the U.S. or Major EU Country, CELGENE shall pay EPIZYME the [**] IND License Option Payment as set forth in Section 6.5.1 or the [**] IND License Option Payment as set
forth in Section 6.5.3, as applicable (either such payment, an “IND License Option Payment”), (b) such Available Target and Compounds Directed to such Available Target shall continue to be focus of activities under the
Research Plan, (c) such Available Target shall remain an Available Target, and (d) the licenses granted in Section 5.1.2 shall automatically be deemed granted with respect to Compounds, Licensed Compounds and Licensed Products
Directed to such Available Target. If CELGENE does not exercise the IND Option with respect to an Available Target during the IND Option Period for such Available Target, such Available Target shall be deemed a Lapsed


  
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Target, and such Lapsed Target shall no longer be an Available Target. If CELGENE does exercise the IND Option with respect to an Available Target during the Selection Term, and the relevant IND
filed by EPIZYME in the U.S. or a Major EU Country does not become effective (without limitation of EPIZYME’s right to refile such IND to obtain effectiveness) or EPIZYME does not file the relevant IND either in the U.S. or in a Major EU
Country, then (i) CELGENE’s exercise of the IND Option with respect to such Available Target shall be deemed withdrawn, (ii) the IND Option Period shall reset with respect to such Available Target, and (iii) CELGENE shall
continue to have the IND Option with respect to such Available Target through the IND Option Period for the next applicable Development Candidate (which may include the same Development Candidate under an IND refiled by EPIZYME to obtain
effectiveness), if any, Directed to such Available Target. 
 2.9.2 Phase 1 Option. On an Available Target-by-Available Target basis,
CELGENE shall have the exclusive right, exercisable at CELGENE’s sole discretion (the “Phase 1 Option”) in accordance with Section 2.9.3, to select Targets from the Available Targets (each, a “Selected
Target”) against which the Parties or CELGENE, as applicable, shall conduct further research and Development of one or more designated Compounds (including Development Candidate(s)). Each designated Compound (including Development
Candidate(s)) Directed to a Selected Target shall be the focus of activities under a Development Plan. While the Parties shall discuss the characteristics and relative scientific merits of each Available Target that is of potential interest, CELGENE
shall have the final decision of whether to exercise the Phase 1 Option with respect to each Available Target. 
 2.9.3 Exercise of Phase
1 Option. On an Available Target-by-Available Target basis, except as provided in Section 2.4, if CELGENE wishes to exercise the Phase 1 Option, CELGENE shall provide to EPIZYME written notice of exercise of such Phase 1 Option with respect
to the Available Target (“Phase 1 Notice of Exercise”) during the applicable Selection Term. Following any such Phase 1 Notice of Exercise by CELGENE, except as provided in Section 2.4 and subject to obtaining all applicable
consents, clearances, waivers, licenses, orders, registrations, approvals, permits, rulings and authorizations under the HSR Act and Antitrust Laws pursuant to Section 2.7.2, CELGENE shall pay EPIZYME the [**] EOP1 License Option Payment as set
forth in Section 6.5.1 or the [**] EOP1 License Option Payment, as set forth in Section 6.5.3, as applicable (either such payment, an “EOP1 License Option Payment”). 

2.9.4 Effect of Exercise of Phase 1 Option. Upon exercise of the applicable Phase 1 Option with respect to an Available Target and
CELGENE’s payment of the applicable EOP1 License Option Payment pursuant to Section 2.9.3, and subject to obtaining all applicable consents, clearances, waivers, licenses, orders, registrations, approvals, permits, rulings and
authorizations under the HSR Act and Antitrust Laws pursuant to Section 2.7.2, the following shall occur: 
 (a) such Available Target
shall become a Selected Target; 
 (b) with respect to such Selected Target, each Compound that meets the criteria of a Licensed Compound
at such time (and for purposes of clarity, with respect to such Selected Target, thereafter during the Term) shall be deemed a Licensed Compound; and 

(c) the license granted in Section 5.1.2 shall terminate and the license granted in Section 5.1.3 shall automatically be deemed
granted with respect to Licensed Compounds and Licensed Products Directed to such Selected Target. 

  
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 2.9.5 Expiration of Phase 1 Option. On an Available Target-by-Available Target basis, if
CELGENE fails to provide its Phase 1 Notice of Exercise before the expiration of the applicable Selection Term for such Available Target, then (a) the Phase 1 Option shall expire with respect to such Available Target, (b) such Available
Target shall be deemed a Lapsed Target, (c) such Lapsed Target shall no longer be an Available Target, and (d) the license granted to CELGENE under Section 5.1.2 shall terminate. 

2.10 Reports; Results. Subject to Sections 2.3.6 and 2.8.2, each Party shall provide written progress reports on the status of its
activities under the Research Plan during the Collaboration, on an Available Target-by-Available Target, including detailed summaries of data associated with such activities and, in the case of EPIZYME, reasonably detailed summaries of data
generated in the course of its ongoing platform discovery activities to the extent not previously provided to CELGENE and relevant to the identification or attractiveness for selection of potential Available Targets under Section 2.9.3, at
least [**] Business Days in advance of each JRC meeting. 
 2.11 Subcontracting. 

2.11.1 Subject to the terms of this Agreement, each Party shall have the right to engage Affiliates or Third Party subcontractors to perform
certain of its obligations under this Agreement. Any Affiliate or subcontractor to be engaged by a Party to perform a Party’s obligations set forth in this Agreement shall meet the qualifications typically required by such Party for the
performance of work similar in scope and complexity to the subcontracted activity, shall comply with the confidentiality and non-use obligations set forth in Article 9, and shall perform such work consistent with the terms of this Agreement;
provided however that any Party engaging an Affiliate or subcontractor hereunder shall remain principally responsible and obligated for such activities. In addition, any Party engaging a subcontractor shall in all cases retain
or obtain Control of any and all Know-How or Patents related to the Collaboration, which may be created by or used with the relevant Party’s permission by such subcontractor in connection with such subcontracted activity (other than Know-How
and Patents that are not specific to the Collaboration and that are related to the subcontractor’s broader technology platform or business). 

2.11.2 Each Party shall have the right to audit and inspect the other Party’s activities under the Research Plan and the Development
Plans, which shall include the right to access the other Party’s records (including records from its Affiliates and major subcontractors regarding work conducted under the Research Plan and the Development Plans) and facilities as reasonably
requested by the requesting Party to confirm the other Party’s compliance with the requirements of and performance under this Agreement. Such audit and inspection shall not be performed more than [**] in any Calendar Year and shall be
reasonably coordinated in advance between the Parties. Each Party shall use Commercially Reasonable Efforts to obtain the right for the other Party to audit the facilities of the Party’s major subcontractors. If a Party cannot


  
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secure such audit rights for the other Party, then to the extent that Party has the right itself to audit its subcontractors’ facilities, it shall conduct such audit as reasonably requested
by the auditing Party and on the terms agreed with such subcontractor and share the results with the auditing Party. 
 2.12 Regulatory
Matters; Compliance. 
 2.12.1 Compliance. The Parties shall conduct all of their respective activities under this Agreement in
good scientific manner, and shall comply in all material respects with all applicable Laws including all applicable FDA and other current international regulatory requirements and standards, including, as applicable, FDA’s cGMP, GLP and current
good clinical practices requirements (21 C.F.R. Parts 50, 54, 56, 58, 210, 211, and 312), and comparable foreign regulatory standards, and other applicable Laws, including requirements for the public dissemination of clinical trial information (42
U.S.C. § 282). For clarity, either Party may at any time suspend or terminate any Clinical Trial it is conducting or responsible for conducting if (a) a priori protocol defined stopping rules are met for safety or efficacy or (b) with
respect to any Licensed Product, safety signals are observed by such Party that present an unacceptable risk to patients participating in such Clinical Trial or (c) if applicable, with respect to any Licensed Product, the data and safety
monitoring board overseeing such Clinical Trial determines such Licensed Product presents an unacceptable risk to patients participating in such Clinical Trial; provided that such Party shall first notify and consult with the JDC. Further, in the
event a Party suspends or terminates a Clinical Trial pursuant to subclause (b) of the immediately preceding sentence, such Party shall immediately notify the other Party and the Parties shall meet as soon as possible to discuss planned
actions. Any implementation of a decision of the JDC will be reviewed in a timely manner with the applicable Regulatory Authorities prior to implementation of such decision. 

2.12.2 Data Integrity. Each of the Parties acknowledges the importance of ensuring that the activities conducted under this Agreement
are undertaken in accordance with the following good data management practices, and shall use Commercially Reasonable Efforts to ensure the following: 

(a) data are being generated using sound scientific techniques and processes; 

(b) data are being accurately and reasonably contemporaneously recorded in accordance with good scientific practices by personnel conducting
research or development hereunder; 
 (c) data are being analyzed appropriately without bias in accordance with good scientific practices;
and 
 (d) data and results are being stored securely and can be easily retrieved. 

  
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 2.12.3 Regulatory Filings, Data and Approvals. For purposes of this Section 2.12.3,
references to each Party shall include (x) Affiliates of such Party designated by such Party, (y) its Sublicensees and (z) its licensees, as the case may be. 

(a) Regulatory Filings. 

(i) DOT1L 
 (1)
CELGENE Territory. From and after the completion of the first Phase 1 Clinical Trial for a Licensed Compound Directed to DOT1L, or if EPIZYME exercises a EPIZYME Post-EOP1 Clinical Opt-Out pursuant to Section 2.5, CELGENE shall have the
sole right to prepare, file and maintain all regulatory filings (including pricing and reimbursement approvals) and Regulatory Approvals necessary for the Development, Manufacture or Commercialization of all Licensed Compounds and Licensed Products
Directed to DOT1L and all related Diagnostic Products in the Field in the CELGENE Territory, and to the extent permitted by applicable Laws and to the extent not assigned and transferred as of the Effective Date, EPIZYME shall assign and transfer to
CELGENE, within [**] days after the completion of such Phase 1 Clinical Trial or after such EPIZYME Post-EOP1 Clinical Opt-Out or such EPIZYME Late Stage Opt-Out, all regulatory filings and Regulatory Approvals in the CELGENE Territory that relate
to any and all Licensed Compounds and Licensed Products directed to DOT1L and all related Diagnostic Products. From and after the completion of the first Phase 1 Clinical Trial for a Licensed Compound Directed to DOT1L, or after such EPIZYME
Post-EOP1 Clinical Opt-Out or such EPIZYME Late Stage Opt-Out, CELGENE shall own all such regulatory filings and Regulatory Approvals necessary for the Development, Manufacture or Commercialization of Licensed Compounds, Licensed Products and
related Diagnostic Products in the CELGENE Territory. 
 (2) EPIZYME Territory. Except as provided in Sections 2.5 and 2.6, EPIZYME
shall have the sole right to prepare, file and maintain all regulatory filings (including pricing and reimbursement approvals) and Regulatory Approvals necessary for the Development, Manufacture or Commercialization of all Licensed Compounds and
Licensed Products Directed to DOT1L and all related Diagnostic Products in the Field in the EPIZYME Territory. EPIZYME shall own all such regulatory filings and Regulatory Approvals necessary for the Development, Manufacture or Commercialization of
Licensed Compounds and Licensed Products and related Diagnostic Products in the EPIZYME Territory. 
 (ii) Available Targets Prior to
Exercise of Phase 1 Option. Except as provided in Section 2.4, prior to CELGENE’s exercise of the Phase 1 Option for an Available Target, EPIZYME shall have the sole right to prepare, file and maintain all regulatory filings and
Regulatory Approvals necessary for the research, Development or Manufacture of Licensed Compounds and Licensed Products Directed to such Available Target, and related Diagnostic Products, in the Field worldwide. 

  
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 (iii) After Exercise of Phase 1 Option. 

(1) CELGENE Territory. Following CELGENE’s exercise of the Phase 1 Option for an Available Target in accordance with
Section 2.9.3, or earlier as provided in Section 2.4, CELGENE shall have the sole right to prepare, file and maintain all regulatory filings (including pricing and reimbursement approvals) and Regulatory Approvals necessary for the
Development, Manufacture or Commercialization of all Licensed Compounds and Licensed Products Directed to such Available Target and all related Diagnostic Products in the Field in the CELGENE Territory. CELGENE shall own all such regulatory filings
and Regulatory Approvals necessary for the Development, Manufacture or Commercialization of such Licensed Compounds, Licensed Products and related Diagnostic Products in the CELGENE Territory. 

(2) EPIZYME Territory. Following CELGENE’s exercise of the Phase 1 Option for an Available Target in accordance with
Section 2.9.3, except as provided in Sections 2.4, 2.5 and 2.6, EPIZYME shall have the sole right to prepare, file and maintain all regulatory filings (including pricing and reimbursement approvals) and Regulatory Approvals necessary for the
Development, Manufacture or Commercialization of all Licensed Compounds and Licensed Products Directed to such Available Target and all related Diagnostic Products in the Field in the EPIZYME Territory. EPIZYME shall own all such regulatory filings
and Regulatory Approvals necessary for the Development, Manufacture or Commercialization of Licensed Compounds and Licensed Products and related Diagnostic Products in the EPIZYME Territory. 

(iv) Access. Each Party shall have access to all data contained or referenced in such regulatory filings and submissions or
applications for Regulatory Approvals necessary for the research, Development, Manufacture or Commercialization of Licensed Compounds, Licensed Products and related Diagnostic Products, including all reports, correspondence and conversation logs in
a timely manner, in each case as may be reasonably necessary to enable (A) CELGENE to Develop, Manufacture and Commercialize the Licensed Compound, Licensed Product and related Diagnostic Product in the Field in the CELGENE Territory and
(B) EPIZYME to Develop, Manufacture and Commercialize the Licensed Compound, Licensed Product and related Diagnostic Product in the Field in the EPIZYME Territory. Each Party shall provide appropriate notification of such right of the other
Party to the Regulatory Authorities. 
 (b) Regulatory Meetings. 

(i) CELGENE Territory. With respect to Licensed Products Directed to DOT1L or [**], subject to CELGENE’s reasonable discretion,
EPIZYME will have the right to fully participate in all material meetings and other material contact with Regulatory Authorities pertaining to the Development, Manufacture and Commercialization of the Licensed Products and related Diagnostic
Products or Regulatory Approvals in the EMA and in the Major EU Countries, Canada, China, India, Japan and Mexico (such countries being referred to hereinafter as “Major License Countries”) upon prior reasonable written request, and
in all other countries of the CELGENE Territory upon mutual agreement of the Parties, in each case, on a Licensed Product-by-Licensed Product basis, (x) in the case of a Licensed Product Directed to [**], from and after CELGENE’s exercise
of the Phase 1 Option with respect to such Licensed 

  
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Product, and (y) in the case of a Licensed Product Directed to DOT1L, from and after the Effective Date. CELGENE shall provide EPIZYME with reasonable advance written notice of all such
meetings and other contact and advance copies of all material related documents and other material relevant information relating to such meetings or such other contact. CELGENE and EPIZYME shall discuss any material documents or other material
correspondence that CELGENE is planning to submit in connection with Regulatory Approvals from the Major License Countries including the proposed labeling for the Licensed Products and related Diagnostic Products. Upon EPIZYME’s reasonable
written request therefor, CELGENE shall provide EPIZYME with drafts of such documents or correspondence sufficiently in advance of submission so that EPIZYME may review and comment on such documents and such other correspondence and have a
reasonable opportunity to influence the substance of such submissions in a manner consistent with the goal of obtaining optimal Regulatory Approvals as quickly as reasonably practicable, which comments shall be considered in good faith by CELGENE.
EPIZYME shall not have the right to approve the proposed labeling or any other regulatory filings or submissions for the Licensed Products and related Diagnostic Products in the CELGENE Territory. CELGENE shall promptly provide to EPIZYME copies of
any material documents or other material correspondence pertaining to the Licensed Product or related Diagnostic Product in the United States (if within the CELGENE Territory), the EMA and the Major License Countries and shall promptly provide to
EPIZYME all proposed labeling, in each case received from the Regulatory Authorities in the United States (if within the CELGENE Territory), the EMA and the Major License Countries. Upon EPIZYME’s reasonable written request, CELGENE shall
provide EPIZYME with any English translations of the documents and correspondence described in this Section 2.12.3(b)(i) that are produced for its own use. 

(ii) EPIZYME Territory. Subject to EPIZYME’s reasonable discretion, CELGENE will have the right to fully participate in all
material meetings and other material contact with Regulatory Authorities pertaining to the Development, Manufacture and Commercialization of the Licensed Products Directed to (x) DOT1L and related Diagnostic Products or Regulatory Approvals in
the EPIZYME Territory from and after the Effective Date, and (y) [**] and related Diagnostic Products or Regulatory Approvals in the EPIZYME Territory from and after exercise of the Phase 1 Option with respect to [**], solely to the extent that
CELGENE and its Affiliates (whether alone or with or for any Third Party) are not engaged in a [**] at such time, upon prior reasonable written request, in each case, on a Licensed Product-by-Licensed Product basis. EPIZYME shall provide CELGENE
with reasonable advance written notice of all such meetings and other contact and advance copies of all material related documents and other material relevant information relating to such meetings or such other contact. EPIZYME and CELGENE shall
discuss any material documents or other material correspondence that EPIZYME is planning to submit in connection with Regulatory Approvals for Licensed Products and related Diagnostic Products or Regulatory Approvals, including the proposed labeling
for the Licensed Products and related Diagnostic Products. Upon CELGENE’s reasonable written request therefor, EPIZYME shall provide CELGENE with drafts of such documents or correspondence sufficiently in advance of submission so that CELGENE
may review and comment on such documents and such other correspondence and have a reasonable opportunity to influence the substance of such submissions in a manner consistent with the goal 

  
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of obtaining optimal Regulatory Approvals as quickly as reasonably practicable, which comments shall be considered in good faith by EPIZYME. CELGENE shall not have the right to approve the
proposed labeling or any other regulatory filings or submissions for the Licensed Products and related Diagnostic Products in the EPIZYME Territory. EPIZYME shall promptly provide to CELGENE copies of any material documents or other material
correspondence pertaining to the Licensed Product or related Diagnostic Product and shall promptly provide to CELGENE all proposed labeling, in each case received from the Regulatory Authorities. Upon CELGENE’s reasonable written request,
EPIZYME shall provide CELGENE with any English translations of the documents and correspondence described in this Section 2.12.3(b)(ii) that are produced for its own use. 

(c) INDs. Unless otherwise agreed by the Parties or as may be required by applicable Regulatory Authorities, on a Licensed
Product-by-Licensed Product basis, following CELGENE’s exercise of the applicable Phase 1 Option relating to the applicable Licensed Compound, each Party shall own all INDs filed by it for purposes of performing its Development responsibilities
with respect to Licensed Products. In furtherance of the foregoing, (i) EPIZYME shall transfer and assign to CELGENE all INDs in the CELGENE Territory that relate to Licensed Compounds and Licensed Products directed to Selected Targets
following such exercise of the applicable Phase 1 Option in the CELGENE Territory; and (ii) CELGENE shall have the right to review and comment on any and all INDs filed in the CELGENE Territory by EPIZYME at least [**] days prior to such
filing, which comments shall be considered in good faith by EPIZYME. Subject to Section 6.4, each Party shall have the right to cross-reference and make any other use of the other Party’s INDs and the data referred to in
Section 2.12.3(a)(iv) for the Licensed Products that it would have if it were the owner, including access to all data contained or referenced in such INDs, in each case as may be reasonably necessary to enable EPIZYME or CELGENE to research,
Develop, Manufacture or Commercialize the Licensed Products in the EPIZYME Territory or the CELGENE Territory, respectively. In addition, subject to Section 6.4, each Party shall have the right to cross-reference the other Party’s Drug
Master File(s) (if any) in connection with the performance of its obligations under this Agreement. 
 (d) Pricing and Reimbursement
Approval Proceedings. 
 (i) CELGENE Territory. CELGENE and its Affiliates shall take the lead in all pricing and reimbursement
approval proceedings relating to the Licensed Products in the CELGENE Territory. CELGENE shall consult with EPIZYME through the JCC with respect to pricing and reimbursement approvals in the CELGENE Territory with respect to Licensed Products for
which the CELGENE Territory is not worldwide. 
 (ii) EPIZYME Territory. EPIZYME and its Affiliates shall take the lead in all
pricing and reimbursement approval proceedings relating to the Licensed Products in the EPIZYME Territory. EPIZYME shall consult with CELGENE through the JCC with respect to pricing and reimbursement approvals in the EPIZYME Territory. 

2.12.4 Adverse Event Reporting; Global Safety Database. CELGENE shall be solely responsible for reporting all adverse drug experiences
associated with Licensed 

  
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Compounds and Licensed Products in the Field in the CELGENE Territory, and for establishing, holding and maintaining the global safety database for Licensed Compounds and Licensed Products in the
Field for which the CELGENE Territory is worldwide. EPIZYME shall be solely responsible for reporting all adverse drug experiences associated with Licensed Compounds and Licensed Products in the Field in the EPIZYME Territory, and for establishing,
holding and maintaining the global safety database for Licensed Compounds and Licensed Products in the Field for which the CELGENE Territory is not worldwide. Each Party shall provide the other Party with all Licensed Compound, Licensed Product and
Diagnostic Product complaints, adverse event information and safety data from clinical studies, in its possession and control, necessary or desirable for the other Party to comply with all applicable Law with respect to the Licensed Compound,
Licensed Product and Diagnostic Product. Further, the Parties shall commence good faith discussion with respect to entering into a separate pharmacovigilance agreement, as and when required by the JDC. 

2.12.5 Material Transfer. 

(a) Either Party (referred to in this Section 2.12.5 as the “Transferring Party”) may, at its sole discretion and as
approved by the JRC, provide to the other Party (referred to in this Section 2.12.5 as the “Material Receiving Party”) certain biological materials or compounds, including assays and research tools in the possession of and
controlled by the Transferring Party (such materials or compounds provided hereunder are referred to, collectively, as “Materials”) for use by the Material Receiving Party in furtherance of its rights and the conduct of its
obligations under this Agreement (the “Purpose”). All transfers of such Materials by the Transferring Party to the Material Receiving Party shall be documented in writing (the “Transfer Record”) that sets forth the
type and name of the Material transferred, the amount of the Material transferred, the date of the transfer of such Material and the Purpose. 

(b) Except as otherwise provided under this Agreement, all such Materials delivered by the Transferring Party to the Material Receiving Party
shall remain the sole property of the Transferring Party, shall only be used by the Material Receiving Party in furtherance of the Purpose, and shall be returned to the Transferring Party or destroyed upon the termination of this Agreement or upon
the discontinuation of the use of such Materials (whichever occurs first). The Material Receiving Party shall not cause the Materials to be used by or delivered to or for the benefit of any Third Party without the prior written consent of the
Transferring Party unless such Third Party is a Third Party subcontractor as set forth in Section 2.11 or a Sublicensee pursuant to Section 5.1.6 or Section 5.2.6. 

(c) At the time the Transferring Party provides Materials to the Material Receiving Party as provided herein and to the extent not separately
licensed under this Agreement, the Transferring Party hereby grants to the other Party a non-exclusive license under the Patents and Know-How Controlled by it to use such Materials solely for the Purpose, and such license, upon termination of this
Agreement, completion of the Purpose, or discontinuation of the use of such Materials (whichever occurs first), shall automatically terminate. 

  
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 (d) The Parties agree that the exchanged Materials: 

(1) shall at all times be Manufactured in accordance with all applicable Laws, rules and regulations, in accordance with the terms of this
Agreement and any applicable quality agreement or any further supply arrangements entered into by the Parties, and shall conform to any specifications agreed upon between the Parties; 

(2) shall be used in compliance with applicable Law; 

(3) shall not be used in animals intended to be kept as domestic pets; 

(4) shall not be transferred to a Third Party except if this is provided for and is done in accordance with this Agreement; and 

(5) shall not be reverse engineered or chemically analyzed, except if this is provided for in the Research Plan or the applicable Development
Plan. 
 (e) THE MATERIALS SUPPLIED BY THE TRANSFERRING PARTY UNDER THIS SECTION 2.12.5 ARE SUPPLIED “AS IS” AND NOT FOR USE IN
HUMANS EXCEPT AS EXPRESSLY AGREED BY THE PARTIES IN WRITING, AND, EXCEPT AS OTHERWISE SET FORTH IN THIS AGREEMENT, THE TRANSFERRING PARTY MAKES NO REPRESENTATIONS AND EXTENDS NO WARRANTIES OF ANY KIND, EITHER EXPRESS OR IMPLIED, INCLUDING WARRANTIES
OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, OR THAT THE USE OF THE MATERIALS DOES NOT INFRINGE ANY PATENT, COPYRIGHT, TRADEMARK, OR OTHER PROPRIETARY RIGHTS OF A THIRD PARTY. 

(f) The Material Receiving Party assumes all liability for damages that may arise from its use, storage or disposal of the Materials. Except
as otherwise set forth in this Agreement, the Transferring Party shall not be liable to the Material Receiving Party for any loss, claim or demand made by the Material Receiving Party, or made against the Material Receiving Party by any Third Party,
due to or arising from the use of the Materials, except to the extent such loss, claim or demand is caused by the willful misconduct of the Transferring Party. 

ARTICLE 3 
 DEVELOPMENT
AND COMMERCIALIZATION 
 3.1 Development Plans. On a Development Program-by-Development Program basis, as soon as possible
following CELGENE’s exercise of the Phase 1 Option relating to a Selected Target, (a) with respect to any Shared Development Program, the Parties (acting through the JDC) shall establish a Development Plan if not previously established
pursuant to Section 2.3.5, including a budget pursuant to Section 6.3.2(a), covering the global Development of Licensed Compounds and Licensed Products Directed to the Selected Target, and related Diagnostic Products, and (b) with
respect to any CELGENE Development Program, CELGENE shall establish a Development Plan if not previously established pursuant to Section 2.3.5 covering the global Development of Licensed Compounds and Licensed Products Directed to the Selected
Target, and related Diagnostic Products (and, for clarity, such Development Plans under 

  
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this clause (b) shall not be subject to the review or approval of the JDC and CELGENE shall retain final decision-making authority related thereto, subject to EPIZYME’s right to review
and provide comments on such Development Plan, which comments CELGENE shall consider in good faith), provided however that the Development Plan established under the Original Agreement for the Development Program relating to DOT1L
shall continue to be the Development Plan for such Development Program under this Agreement. Each Development Plan established under clause (a) above and the Development Plan with respect to DOT1L shall allocate responsibilities for Development
activities to the Parties with a guiding principle that each Party shall play a meaningful role in the Development of Licensed Compounds and Licensed Products Directed to the Selected Target and related Diagnostic Products. Each Development Plan
established under clause (b) above shall reflect that CELGENE has the sole responsibility for the Development of the Licensed Compounds and Licensed Products Directed to the Selected Target and related Diagnostic Products and that, other than
as set forth in this Section 3.1, EPIZYME shall not have any role in such Development. On a Shared Development Program-by-Shared Development Program basis, the Parties shall mutually select a global development lead, who shall be responsible
for matters including global operations, safety reporting and drug supply (the “Global Development Lead”); provided that, with respect to any strategic decision-making (which for clarity, includes matters related to regulatory
affairs, Development Plans and protocols for Clinical Trials), the Global Development Lead shall be subject to the oversight of the JDC; provided further, that from time to time, the Parties may mutually agree to allocate specified functions
otherwise designated to the Global Development Lead to either Party. Subject to Sections 3.2.2, 4.7 and 6.4, the Parties agree to conduct all of their Development activities with respect to each Development Program in accordance with the applicable
Development Plan and, in the case of Shared Development Programs, the budget for such Shared Development Programs established in accordance with this Agreement. 

3.2 Development Activities. 

3.2.1 Generally. During the Development Term for a particular Development Program and subject to Section 4.7, each Party
shall be responsible for, and shall use Commercially Reasonable Efforts to perform, the Development activities assigned to such Party, if any, under the applicable Development Plan. Unless otherwise agreed by the Parties, with respect to a Shared
Development Program, Pivotal Clinical Trial(s) conducted pursuant to each Development Plan shall be designed so that such Pivotal Clinical Trial(s), to the extent reasonably possible, satisfy regulatory requirements in both the United States and
Europe. During the Development Term for a particular Shared Development Program, each Party shall provide written notice to the other Party of each Clinical Trial it will conduct at least [**] days prior to the Initiation of such Clinical Trial,
together with a copy of the protocols and other material documentation and information related to such Clinical Trial for review and comment by the other Party, which comments shall be considered in good faith by the Party conducting the Clinical
Trial prior to Initiation of such Clinical Trial. Each Party shall have the right to conduct any Development activities in the other Party’s territory, subject to the terms and conditions of this Agreement. Notwithstanding anything to the
contrary in this Agreement, a Party may conduct any Development or Commercialization activities with respect to its territory that the FDA or equivalent Regulatory Authority in such Party’s territory requires such Party to conduct


  
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to obtain Regulatory Approval of the applicable Licensed Product or related Diagnostic Products in such country, and the Development Costs related to such Development activities shall, with
respect to Shared Development Programs, be Territory-Specific Development Costs of such Party. Further, in the event a Party desires to clinically Develop a Licensed Compound or Licensed Product generated from a Shared Development Program for
non-oncology Indication(s), the Parties shall mutually agree upon the clinical Development of such Licensed Product for non-oncology Indication(s) prior to the commencement of the first such non-oncology Clinical Trial of such Licensed Product,
regardless if such Clinical Trial incurs Global Development Costs or Territory-Specific Development Costs, and regardless of whether a Business Combination occurs with respect to a Party. 

3.2.2 [**]. If and only for as long as CELGENE or any of its Affiliates (whether alone or with or for any Third Party) engages
in a [**], after CELGENE’s exercise of the Phase 1 Option with respect to a Development Candidate Directed to [**], the following shall apply (except where CELGENE has obtained final decision making authority pursuant to Sections 2.4, 2.5 or
2.6):  
 (a) If, following CELGENE’s exercise of the Phase 1 Option with respect to a Development Candidate Directed to [**],
a Party (the “Proposing Party”) wishes (i) to conduct a Clinical Trial or other Development activities as to a Development Candidate for the CELGENE Territory (where the Proposing Party is CELGENE), the EPIZYME Territory (where
EPIZYME is the Proposing Party) or for global purposes (where either Party is the Proposing Party) (each such study, an “[**] Study”), then (A) the Proposing Party shall first provide the proposed trial design and protocol for
such [**] Study to the JDC for review and approval as to the clinical and regulatory aspects of such [**] Study, and shall incorporate reasonable comments from the JDC into such [**] Study design and protocol, and (B) following such review by
the JDC, provide the final proposed design and projected costs of such [**] Study to the JDC. 
 (b) If the other Party (the
“Non-Proposing Party”), through its members of the JDC, agrees to co-fund such [**] Study, the Parties shall amend the applicable Development Plan and the costs of such [**] Study shall be Global Development Costs. If the Parties
agree to include the costs of any [**] Study as Global Development Costs, all resulting data would be available for use by each Party in connection with exercising its rights under this Agreement. 

(c) If the Non-Proposing Party does not wish to include costs incurred with respect to such proposed [**] Study as Global Development Costs,
but the Non-Proposing Party has no material objection to such [**] Study as set forth in Section 3.2.2(d), the Proposing Party may proceed with such [**] Study and would be solely responsible for the conduct and costs of such study. In such
case, the rights and obligations of the Proposing Party and Non-Proposing Party, including with respect to the subsequent use of any resulting data by the Non-Proposing Party, shall be as set forth in Section 6.4 as if such [**] Study were a
territory-specific Development activity, with the Proposing Party as the Sole Paying Party and the Non-Proposing Party as the Non-Paying Party; 

  
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 (d) Notwithstanding Sections 3.2.2(a) and (b), if the Non-Proposing Party believes a proposed
[**] Study would be likely to have a material adverse effect on the ability to obtain Regulatory Approval for the relevant Development Candidate, Licensed Candidate or Licensed Product in the Non-Proposing Party’s territory, or on the
regulatory status or Commercialization of such Development Candidate, Licensed Candidate or Licensed Product in the Non-Proposing Party’s territory (an “Adverse Study Effect”), such Non-Proposing Party would have the right to
refer such matter to the JDC and, as needed, the JDC shall review such Non-Proposing Party’s concerns and consider mechanisms to mitigate or obviate any such concerns. If the JDC does not agree upon whether or not a proposed [**] Study would
have an Adverse Study Effect, such matter shall be submitted for resolution by arbitration pursuant to Section 13.2.1. 
 3.3
Reports. 
 3.3.1 On a Shared Development Program-by-Shared Development Program basis, during the applicable Development Term, each
Party shall provide the other Party with written reports summarizing the material activities of the Party, its Affiliates and Sublicensees with respect to the then-current expected future plans and timetable for Development of Licensed Compounds,
Licensed Products and related Diagnostic Products in the Field in the CELGENE Territory or in the EPIZYME Territory, as applicable, for each Licensed Compound and/or Licensed Product in such Development Program, within [**] days after the end of
each Calendar Quarter. If the receiving Party has any questions with respect to the information set forth in any report provided to it under this Section 3.3, the receiving Party shall direct such questions to the other Party’s Alliance
Manager, who shall make reasonably available to the receiving Party appropriate technical or scientific personnel who are knowledgeable about the Development activities conducted by such other Party to respond to such questions in a timely manner,
via teleconference, in person or such other mode of communication as the Parties may mutually agree. 
 3.3.2 On a CELGENE Development
Program-by-CELGENE Development Program basis, during the applicable Development Term, CELGENE shall, on a [**] basis, provide the JDC with an update summarizing the material Development activities of CELGENE, its Affiliates and Sublicensees with
respect to Licensed Compounds, Licensed Products and related Diagnostic Products in the Field in the CELGENE Territory in such CELGENE Development Program. 

3.3.3 The Parties’ obligations under this Section 3.3 shall end, on a Development Program-by-Development Program basis, upon the
First Commercial Sale of a Licensed Product related to such Development Program if no material Development activities are being conducted or planned to be conducted by the Parties with respect to such Development Program at the time of such First
Commercial Sale. 
 3.4 Commercialization. 

3.4.1 Responsibility. On a Development Program-by-Development Program basis, following completion of the applicable Development Term,
CELGENE shall have the sole 

  
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right and responsibility for all Commercialization activities in connection with the Licensed Compounds, Licensed Products and Diagnostic Products of such Development Program in the CELGENE
Territory. On a Development Program-by-Development Program basis, following completion of the applicable Development Term, EPIZYME shall have the sole right and responsibility for all Commercialization activities in connection with the Licensed
Compounds, Licensed Products and Diagnostic Products of such Development Program in the EPIZYME Territory. 
 3.4.2 Meetings. Without
limiting the generality of any of the foregoing in this Section 3.4, on a Shared Development Program-by-Shared Development Program basis, following completion of the applicable Development Term, the Parties (acting through the JCC) shall meet
[**] to discuss the status of, and any updates with respect to, each Party’s efforts (if any) to Commercialize Licensed Compounds, Licensed Products and Diagnostic Products of such Development Program. 

3.4.3 Reports; Results; Adverse Events. 

(a) On a Shared Development Program-by-Shared Development Program basis, following completion of the applicable Development Term, each Party
(acting through the JCC) shall provide the other Party with periodic written reports summarizing the material activities and anticipated plans of such Party, its Affiliates and Sublicensees with respect to the Commercialization of Licensed
Compounds, Licensed Products and Diagnostic Products of such Development Program in such Party’s respective territory. Such written reports shall be provided to the other Party at least once every [**] months (and reasonably in advance of each
meeting of the Parties held in accordance with Section 3.4.2). 
 (b) On a CELGENE Development Program-by-CELGENE Development Program
basis, following completion of the applicable Development Term, CELGENE shall provide to EPIZYME, on a semi-annual basis, a written update of its material Commercialization activities with respect to Licensed Compounds, Licensed Products and
Diagnostic Products of such CELGENE Development Program. The Commercialization of Licensed Compounds, Licensed Products and Diagnostic Products of CELGENE Development Programs shall not be subject to the purview of the JCC. 

(c) On a Development Program-by-Development Program basis, following completion of the applicable Development Term, each Party and its
respective Affiliates shall continue to comply with the adverse event reporting obligations contained in Section 2.12.4, provided that, solely with respect to Shared Development Programs, the Parties’ costs and expenses of
maintaining the global adverse event database shall be borne fifty percent (50%) by EPIZYME and fifty percent (50%) by CELGENE. 

3.5 Diligence. CELGENE shall use Commercially Reasonable Efforts (for purposes of clarity, itself or through an Affiliate or
Sublicensee) to Develop, obtain Regulatory Approval for and Commercialize at least (a) [**]. 
 3.6 No Representation. Subject
to the foregoing obligations to use Commercially Reasonable Efforts, neither Party provides any representation, warranty or guarantee that the Collaboration will be successful, or that any particular results will be achieved with respect to the
Collaboration or any Selected Target, Compound (including Licensed Compound), Licensed Product or Diagnostic Product hereunder. 

  
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 ARTICLE 4 

GOVERNANCE 
 4.1 Joint
Research Committee. Pursuant to the Original Agreement, the Parties established a joint research committee (the “JRC”), which shall continue and operate as more fully described in this Section 4.1. The JRC shall have
review, oversight and decision-making responsibilities for all activities performed under the Research Plan, as more specifically provided herein. Each Party agrees to keep the JRC informed of its progress and activities under the Collaboration. The
JRC may establish Subcommittees as set forth in Section 4.4.3. 
 4.1.1 Membership. The JRC shall be comprised of [**]
representatives (or such other number of representatives as the Parties may agree) from each of CELGENE and EPIZYME. Each Party may replace any or all of its representatives on the JRC at any time upon written notice to the other Party in accordance
with Section 13.8. Each representative of a Party shall have sufficient seniority and expertise in biotechnology and pharmaceutical drug discovery and development to participate on the JRC. Each Party may, subject to the other Party’s
prior approval, invite non-member representatives of such Party to attend meetings of the JRC as non-voting participants, subject to the confidentiality obligations of Article 9. [**] shall have the right to designate the chairperson of the JRC.

 4.1.2 Meetings. Until the expiration of the Option Term, the JRC shall meet in person at least [**], and more or less frequently
as the Parties mutually deem appropriate, on such dates and at such places and times as provided herein or as the Parties shall agree. Upon expiration of the Option Term, the JRC shall disband. Meetings of the JRC that are held in person shall
alternate between the offices of the Parties, or such other location as the Parties may agree. The members of the JRC also may convene or be polled or consulted from time to time by means of telecommunications, video conferences, electronic mail or
correspondence, as deemed necessary or appropriate. Each Party will bear all expenses it incurs in regard to participating in all meetings of the JRC, including all travel and living expenses. 

4.1.3 Responsibilities. The JRC shall perform the following functions, subject to the final decision-making authority of EPIZYME as set
forth in Section 4.4.2; provided that, the JRC shall not have any authority with respect to [**]: 
 (a) review and monitor progress
of the Collaboration under the Research Plan; 
 (b) discuss Target validation activities; 

(c) determine chemistry strategy; 

  
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 (d) determine lead optimization strategy, including in vivo pharmacology; 

(e) review and approve changes to the Lead Candidate Criteria for each Available Target, provided that any changes must be
approved by mutual agreement of the Parties; 
 (f) determine whether the applicable Lead Candidate Criteria have been achieved by any
Compound, subject to Section 2.3.4; 
 (g) review and approve changes to the Development Candidate Selection Criteria for each
Available Target, provided that any changes must be approved by mutual agreement of the Parties; 
 (h) determine whether the
applicable Development Candidate Selection Criteria has been achieved by any Compound, subject to Section 2.3.5, and discuss and develop the Development Plan for a Compound, as set forth in Section 2.3.5; 

(i) subject to Section 2.3.6, serve as a forum for exchange of information and to facilitate discussions regarding the conduct of the
Collaboration and the identification of Compounds, any substitute, backup or replacement Compounds (including Licensed Compounds), Licensed Products and Diagnostic Products hereunder, provided that each back-up Compound must be
mutually agreed upon by the Parties to be a back-up Compound; 
 (j) discuss and attempt to resolve any deadlocked issues submitted to it
in accordance with the procedures established in Section 4.4.2; 
 (k) develop, review and approve amendments to the Research Plan
solely by mutual agreement of the Parties; 
 (l) attempt to resolve any dispute in any Subcommittee of the JRC; and 

(m) such other responsibilities as may be assigned to the JRC pursuant to this Agreement or as may be mutually agreed by the Parties from
time to time. 
 For purposes of clarity, the JRC shall not have any authority beyond the specific matters set forth in this Section 4.1.3, and in
particular shall not have any power to amend, modify or waive the terms of this Agreement, or to alter, increase, expand or waive compliance by a Party with, a Party’s obligations under this Agreement. In any case where a matter within the
JRC’s authority arises, the JRC shall convene a meeting and consider such matter within [**] days after the matter is first brought to the JRC’s attention, or, if earlier, at the next regularly-scheduled JRC meeting. 

  
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 4.2 Joint Development Committee. Pursuant to the Original Agreement, the Parties
established a joint development committee (the “JDC”) for DOT1L, which JDC shall continue and operate as more fully described in this Section 4.2 and subject to Section 3.1. The JDC shall have review, oversight and
decision-making responsibilities for all activities performed under the Development Plan for each Shared Development Program during the applicable Development Term, including the overall global Development strategy of Licensed Products and
Diagnostic Products relating to such Shared Development Programs, as more specifically provided herein. Each Party agrees to keep the JDC informed of its progress and activities under the Shared Development Programs. The JDC may establish
Subcommittees as set forth in Section 4.4.3. For clarity, the CELGENE Development Programs shall not be subject to the review, oversight or decision-making responsibilities of the JDC. 

4.2.1 Membership. The JDC shall be comprised of [**] representatives (or such other number of representatives as the Parties may agree)
from each of CELGENE and EPIZYME. Each Party may replace any or all of its representatives on the JDC at any time upon written notice to the other Party in accordance with Section 13.8. Each representative of a Party shall have sufficient
seniority and expertise in biotechnology and pharmaceutical drug discovery and development to participate on the JDC. Each Party may, subject to the other Party’s prior approval, invite non-member representatives of such Party to attend
meetings of the JDC as non-voting participants, subject to the confidentiality obligations of Article 9. [**] shall have the right to designate the chairperson of the Development Program related to DOT1L. Prior to the exercise by CELGENE of the
Phase 1 Option for an Available Target, [**] shall have the right to designate the chairperson of the JDC for the Shared Development Program related to such Available Target. After the exercise by CELGENE of the Phase 1 Option for an Available
Target, [**] shall have the right to designate the chairperson of the JDC for the Shared Development Program related to such Available Target. [**]. 

4.2.2 Meetings. Prior to the expiration of all Development Terms for the Shared Development Programs, the JDC shall meet in person at
least [**], and more or less frequently as the Parties mutually deem appropriate, on such dates and at such places and times as provided herein or as the Parties shall agree. After the end of all Development Terms for the Shared Development
Programs, the JDC shall disband. Meetings of the JDC that are held in person shall alternate between the offices of the Parties, or such other location as the Parties may agree. The members of the JDC also may convene or be polled or consulted from
time to time by means of telecommunications, video conferences, electronic mail or correspondence, as deemed necessary or appropriate. Each Party will bear all expenses it incurs in regard to participating in all meetings of the JDC, including all
travel and living expenses. 
 4.2.3 Responsibilities. The JDC shall perform the following functions with respect to the Shared
Development Programs, subject to the final decision-making authority of the Party designated in Section 4.4.2: 
 (a) develop and
annually review strategy for the Development, Manufacture and Commercialization of Licensed Products and related Diagnostic Products on a worldwide basis; 

  
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 (b) review and monitor progress of the Collaboration under the Development Plans, including any
Development Plans for Compounds developed pursuant to Section 2.3.5; 
 (c) serve as a forum for exchange of information and to
facilitate discussions regarding the conduct of the Development Programs, the Development of Licensed Compounds, Licensed Products and Diagnostic Products hereunder and the coordination of regulatory filing and Regulatory Approvals; 

(d) review and approve clinical study endpoints, clinical methodology and monitoring requirements for the clinical studies described in the
Development Plan with the goal of designing Pivotal Clinical Trials that satisfy regulatory requirements worldwide, and determining whether to suspend or terminate any Clinical Trial if (i) a priori protocol defined stopping rules are met for
safety or efficacy, (ii) with respect to any Licensed Product, safety signals are observed by such Party that present an unacceptable risk to patients participating in such Clinical Trial or (c) if applicable, with respect to any Licensed
Product, the data and safety monitoring board overseeing such Clinical Trial determines such Licensed Product presents an unacceptable risk to patients participating in such Clinical Trial; provided that any decision of the JDC with
respect to suspension or termination of a Clinical Trial for safety reasons will be reviewed in a timely manner with the applicable Regulatory Authorities in accordance with Section 2.12.1; 

(e) develop, review and approve amendments to the Development Plans, including the annual budget therefor as described in
Section 6.3.2(a) and the Development Program Stopping Rules pursuant to Section 2.3.7, which Development Program Stopping Rules can only be amended by mutual agreement of the Parties; 

(f) subject to Section 2.3.7, determine whether to cease Development of a Compound (including Licensed Compound) or Licensed Product,
and to instead pursue a substitute, backup or replacement Compound (including Licensed Compound) or Licensed Product; 
 (g) determine if
and when the Parties shall commence good faith discussion with respect to entering into a pharmacovigilance agreement pursuant to Section 2.12.4; 

(h) discuss and attempt to resolve any deadlocked issues submitted to it in accordance with the procedures established in Section 4.4;

 (i) attempt to resolve any dispute in any Subcommittee of the JDC; and 

(j) such other responsibilities as may be assigned to the JDC pursuant to this Agreement or as may be mutually agreed by the Parties from
time to time. 

  
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 For clarity, the JDC shall not have any authority beyond the specific matters set forth in this
Section 4.2.3, and in particular shall not have any power to amend, modify or waive the terms of this Agreement, or to alter, increase, expand or waive compliance by a Party with, a Party’s obligations under this Agreement. In any case
where a matter within the JDC’s authority arises, the JDC shall convene a meeting and consider such matter within [**] days after the matter is first brought to the JDC’s attention, or, if earlier, at the next regularly-scheduled JDC
meeting. 
 4.3 Joint Commercialization Committee. The Parties have established a joint commercialization committee (the
“JCC”) with respect to Licensed Products Directed to DOT1L, which JCC shall continue and operate as more fully described in this Section 4.3. The purpose of the JCC is to facilitate the discussion and coordination of
Commercialization activities by the Parties with respect to Licensed Products developed under Shared Development Programs, as more fully described in this Section 4.3. The JCC shall have decision-making responsibilities and authority as set
forth in Sections 4.3.3 and 4.3.4. Each Party agrees to keep the JCC informed of its Commercialization progress and activities under the Collaboration with respect to such Licensed Products. The JCC may establish Subcommittees as set forth in
Section 4.4.3. For clarity, Licensed Products developed under the CELGENE Development Programs shall not be within the purview of the JCC. 

4.3.1 Membership. The JCC shall be comprised of [**] representatives (or such other number of representatives as the Parties may agree)
from each of CELGENE and EPIZYME. Each Party may replace any or all of its representatives on the JCC at any time upon written notice to the other Party in accordance with Section 13.8. Each representative of a Party shall have sufficient
seniority and expertise in biotechnology and pharmaceutical drug discovery and commercialization to participate on the JCC. Each Party may, subject to the other Party’s prior approval, invite non-member representatives of such Party to attend
meetings of the JCC as non-voting participants, subject to the confidentiality obligations of Article 9. [**] shall have the right to designate the chairperson of the JCC. 

4.3.2 Meetings. During the Term (or for such shorter period as the Parties may agree), the JCC shall meet in person at least [**], and
more or less frequently as the Parties mutually deem appropriate, on such dates and at such places and times as provided herein or as the Parties shall agree. Upon expiration or termination of this Agreement in its entirety or as otherwise set forth
in this Agreement, the JCC shall disband. Meetings of the JCC that are held in person shall alternate between the offices of the Parties, or such other location as the Parties may agree. The members of the JCC also may convene or be polled or
consulted from time to time by means of telecommunications, video conferences, electronic mail or correspondence, as deemed necessary or appropriate. Each Party will bear all expenses it incurs in regard to participating in all meetings of the JCC,
including all travel and living expenses. 
 4.3.3 Responsibilities. The JCC shall perform the following functions, subject to the
final decision-making authority provisions set forth in Section 4.3.4: 
 (a) advise the JDC on Commercialization strategy for
purposes of Pivotal Clinical Trial planning for each Shared Development Program; provided that the JDC shall retain decision-making authority in accordance with Section 4.2 and 4.4 over all such matters; 

  
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 (b) facilitate discussion and consultation regarding pricing and reimbursement approvals in each
Party’s Territory pursuant to Section 2.12.3(d) with respect to Licensed Compounds, Licensed Products and related Diagnostic Products arising from Shared Development Programs; 

(c) discuss each Party’s efforts to Commercialize Licensed Compounds, Licensed Products and related Diagnostic Products pursuant to
Section 3.4.2 with respect to Licensed Compounds, Licensed Products and related Diagnostic Products arising from Shared Development Programs and facilitate the provision of reports pursuant to Section 3.4.3(a); 

(d) discuss and determine strategy for the Manufacture and Commercialization of Licensed Products and related Diagnostic Products arising
from Shared Development Programs on a worldwide basis; and 
 (e) develop and review [**] plan and long-term plan with respect to strategy
for the Commercialization of Licensed Products and related Diagnostic Products Shared Development Programs on a worldwide basis, including the development, launch, and management of a global brand. 

For clarity, the JCC shall not have any authority beyond the specific matters set forth in this Section 4.3.3, and in particular shall not have any power
to amend, modify or waive compliance with the terms of this Agreement or to alter, increase, expand or waive compliance by a Party with a Party’s obligations under this Agreement. In any case where a matter within the JCC’s authority
arises, the JCC shall convene a meeting and consider such matter within [**] days after the matter is first brought to the JCC’s attention, or, if earlier, at the next scheduled JCC meeting. 

4.3.4 Decisions. All decisions of the JCC shall be made by consensus, with each Party having one vote. If the JCC cannot agree on a
matter within the JCC’s authority within [**] days after it has met and attempted to reach such decision, then, either Party may, by written notice to the other, have such issue referred to the Executive Officers for resolution. The
Parties’ respective Executive Officers shall meet within [**] Business Days after such matter is referred to them, and shall negotiate in good faith to resolve the matter. If the Executive Officers are unable to resolve the matter within [**]
days after the matter is referred to them, then, notwithstanding anything to the contrary in this Agreement, each Party shall have final decision-making authority with respect to its Territory. 

4.4 Procedures of the JRC, JDC and JCC. 

4.4.1 Minutes. The Alliance Manager from the Party other than the Party of the chairperson of the applicable committee shall be
responsible for preparing and circulating minutes of each meeting of the JRC, JDC and JCC, setting forth, inter alia, an overview of the discussions at the meeting and a list of any actions, decisions or determinations approved by the


  
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JRC, JDC or JCC, as applicable, and a list of any issues to be resolved by the Executive Officers pursuant to Section 4.4.2. Such minutes shall be effective only after approved by both
Parties in writing. With the sole exception of specific items of the meeting minutes to which the members cannot agree and that are escalated to the Executive Officers as provided in Section 4.4.2, definitive minutes of all JRC, JDC or JCC
meetings shall be finalized no later than [**] days after the meeting to which the minutes pertain. If, at any time during the preparation and finalization of the JRC, JDC or JCC minutes, the Parties do not agree on any issue with respect to the
minutes, such issue shall be resolved by the escalation process set forth in Section 4.4.2. The decision resulting from the escalation process shall be recorded by the Alliance Manager in amended finalized minutes for such meeting. 

4.4.2 Decisions. Except as otherwise provided herein, all decisions of the JRC, JDC and JCC shall be made by consensus, with each Party
having one vote. If the JRC, JDC or JCC cannot agree on a matter within the JRC’s, JDC’s or JCC’s authority, respectively, within [**] days after it has met and attempted to reach such decision, then, either Party may, by written
notice to the other, have such issue referred to the Executive Officers for resolution. The Parties’ respective Executive Officers shall meet within [**] Business Days after such matter is referred to them, and shall negotiate in good faith to
resolve the matter. 
 (a) Final Decision Making Authority. If the Executive Officers are unable to resolve the matter within [**]
days after the matter is referred to them in accordance with this Section 4.4.2, then: 
 (i) DOT1L. Subject to Sections 2.3.4,
2.3.5, 2.12.1, 3.2, and 4.4.2(b) and (c), CELGENE shall have final decision-making authority with respect to any matter relating to the Development Program relating to DOT1L, and, for purposes of clarity, all global activities related to such
Licensed Compound shall be included in the applicable Development Program. For purposes of clarity, this Section 4.4.2(a)(i) does not apply to the JCC or the Patent Committee. 

(ii) Prior to Exercise of Phase 1 Option. Subject to Sections 2.3.4, 2.3.5, 2.12.1, 3.2, and 4.4.2(a)(i), (b) and (c), EPIZYME shall
have final decision-making authority with respect to any matter relating to activities under the Research Plan prior to CELGENE’s exercise of the Phase 1 Option with respect to the applicable Available Target. For purposes of clarity, this
Section 4.4.2(a)(ii) does not apply to the JCC or the Patent Committee. 
 (iii) After Exercise of Phase 1 Option. Subject to Sections
2.3.4, 2.3.5, 2.12.1, 3.2, and 4.4.2(a)(i), (b) and (c), CELGENE shall have final decision-making authority with respect to any matter relating to any Development Program after CELGENE’s exercise of the Phase 1 Option with respect to the
Available Target that is the subject of such Development Program; provided that, with respect to [**] shall have final decision-making authority with respect to any matter relating to any Development Program after CELGENE’s exercise of the
Phase 1 Option as long as CELGENE or any of its Affiliates (whether alone or with or for any Third Party) engages in a [**] and any such decisions shall be made only by mutual agreement of the Parties, provided that Section 3.2.2 shall apply;
provided further that, with respect to [**], CELGENE shall have the right to exercise final decision-making authority solely upon CELGENE’s and its Affiliates’ completion or termination of [**]. For purposes of clarity, this
Section 4.4.2(a)(iii) does not apply to the JCC or the Patent Committee. 

  
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 (b) Limitations on Decision-Making Authority. The foregoing provisions of
Section 4.4.2 notwithstanding, neither Party shall have the right to exercise its final decision-making authority to unilaterally: (i) determine that it has fulfilled any obligations under this Agreement or that the other Party has
breached any obligation under this Agreement; (ii) determine that milestone events required for the payment of milestone payments have or have not occurred; (iii) make a decision that is expressly stated to require the mutual agreement of
the Parties; (iv) amend any Development Plan to require the Development of any Compound other than the Development Candidate for which clinical Development was first conducted in such Development Program; (v) change or modify the Hit
Criteria, Lead Candidate Criteria or Development Candidate Selection Criteria; (vi) subject to Section 6.4, decide to pursue a Pivotal Clinical Trial with respect to a Shared Development Program that does not satisfy regulatory
requirements in both the United States and Europe; (vii) require or restrict the other Party from conducting Development activities specifically related only to such Party’s territory, except as otherwise set forth herein;
(viii) amend the Research Plan; or (ix) otherwise expand its rights or reduce its obligations under this Agreement. 
 (c)
Business Combination or License Event. Subject to Section 3.2, effective on and after a (i) Business Combination of EPIZYME or (ii) License Event pursuant to which an exclusive license is granted by EPIZYME to a Third Party
with respect to all of EPIZYME’s rights to all applicable Licensed Compounds, Licensed Products and related Diagnostic Products in the applicable Shared Development Program in the EPIZYME Territory, in each case, with a Third Party,
(1) following exercise by CELGENE of the Phase 1 Option with respect to a Selected Target, the Parties shall [**] on issues solely related to the applicable Shared Development Program that arise for the applicable Compounds (including Licensed
Compounds), Licensed Products and Diagnostic Products in such Shared Development Program, with respect to such Business Combination or License Event, and (2) each Party shall have final decision-making authority with respect to any such issues
set forth in clause (1) above with respect to its Territory, except as set forth below. In the event that a [**] in accordance with Section 13.2.1; provided that such [**] shall base its decision on the best commercial
interests of the Compound, Licensed Compound, Licensed Product or Diagnostic Product, as applicable. For purposes of clarity, this Section 4.4.2(c) does not apply to decisions of the JCC or the Patent Committee. 

4.4.3 Subcommittee(s). From time to time, the JRC, JDC or JCC may establish subcommittees to oversee particular projects or activities,
as it deems necessary or advisable (each, a “Subcommittee”). Each Subcommittee shall consist of such number of members as the JRC, JDC or JCC, as applicable, determines is appropriate from time to time. Such members shall be
individuals with expertise and responsibilities in the relevant areas such as high-throughput screening, protein generation, non-clinical Development, pharmacology, clinical Development, patents, process sciences, manufacturing, quality, regulatory
affairs, product Development or product Commercialization, as applicable to the stage of the project or activity. 

  
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 (a) Manufacturing Subcommittee. Under the Original Agreement, the Parties have
established a Subcommittee under the JDC for Manufacturing (including CMC) related matters, which initially is with respect to DOT1L (and thereafter, with respect to each Selected Target at the time a Compound Directed to such Selected Target meets
the Development Candidate Selection Criteria pursuant to Section 2.3.5) (the “Manufacturing Subcommittee”), which Manufacturing Subcommittee shall continue and operate pursuant to this Section 4.4.3 with respect to DOT1L
and any other Shared Development Programs. Notwithstanding anything to the contrary in this Agreement, on a Licensed Compound-by-Licensed Compound basis, (i) CELGENE shall have final decision-making authority with respect to all Manufacturing
matters in such CMC Subcommittee with respect to Licensed Compounds Directed to DOT1L, (ii) prior to CELGENE’s exercise of the Phase 1 Option for the Available Target to which the Licensed Compound is Directed, EPIZYME shall have final
decision-making authority with respect to all Manufacturing matters in such CMC Subcommittee and (iii) after CELGENE’s exercise of the Phase 1 Option for such Available Target, [**] shall have final decision-making authority with respect
to all such matters; provided that, nothing in this Section 4.4.3(a) shall [**]. Prior to CELGENE’s exercise of the Phase 1 Option for the Available Target to which the applicable Licensed Compound is Directed, in the event
CELGENE desires to use or transfer to a Third Party any Manufacturing process selected by EPIZYME on behalf of the Collaboration in connection with an applicable Licensed Compound, Licensed Product or related Diagnostic Product and EPIZYME does not
desire to move the related Manufacturing activities, upon CELGENE’s written request, EPIZYME shall provide a technology transfer of the relevant Know-How to a Third Party designated by CELGENE, at CELGENE’s cost and expense, in order to
enable CELGENE to establish an alternative Manufacturing capability. 
 4.5 Patent Committee. Under the Original Agreement, the
Parties (a) each designated representative(s) to consult with the other Party’s representative(s) with respect to Patent ownership, Prosecution and Maintenance, enforcement and defense matters (the “Patent Liaisons”), and
(b) established a patent committee (the “Patent Committee”), which Patent Liaisons and Patent Committee shall continue and operate as more fully described in this Section 4.5. The purpose of the Patent Committee is to
determine ownership of intellectual property, and facilitate the discussion and coordination of Patent Prosecution and Maintenance, enforcement and defense matters, in accordance with and subject to the terms of Article 8. The Patent Liaisons shall
be the primary point of contact for the Parties regarding the foregoing activities and shall facilitate all such activities hereunder, including preparing and finalizing minutes of the Patent Committee and shall be responsible for assisting the
Patent Committee in performing its oversight responsibilities. The name and contact information for each Party’s Patent Liaison, as well as any replacement(s) chosen by EPIZYME or CELGENE, in their sole discretion, from time to time, shall be
promptly provided to the other Party in accordance with Section 13.8. 
 4.5.1 Membership. The Patent Committee shall be
comprised of an equal number of representatives (which may include the Patent Liaisons) from each of CELGENE and EPIZYME. Each Party may replace any or all of its representatives on the Patent Committee at any time upon written notice to the other
Party in accordance with Section 13.8. Each representative of a Party shall have sufficient seniority and expertise in patent Prosecution and 

  
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Maintenance, enforcement and defense to participate on the Patent Committee. Each Party may, subject to the other Party’s prior approval, invite non-member representatives of such Party to
attend meetings of the Patent Committee as non-voting participants, subject to the confidentiality obligations of Article 9. The Parties shall take turns designating a chairperson to oversee the operations of the Patent Committee, each such
chairperson to serve a twelve (12) month term, and [**] shall designate the first chairperson. 
 4.5.2 Meetings. The Patent
Committee shall convene at such times, places and frequencies as the Patent Committee determines is necessary. Upon expiration or termination of this Agreement in its entirety or as otherwise set forth in this Agreement, the Patent Committee shall
disband. Meetings of the Patent Committee that are held in person shall alternate between the offices of the Parties, or such other location as the Parties may agree. The members of the Patent Committee also may convene or be polled or consulted
from time to time by means of telecommunications, video conferences, electronic mail or correspondence, as deemed necessary or appropriate. Each Party will bear all expenses it incurs in regard to participating in all meetings of the Patent
Committee, including all travel and living expenses. 
 4.5.3 Responsibilities. The Patent Committee shall perform the following
functions, subject to the final decision-making authority provisions set forth in Section 4.5.5: 
 (a) determine ownership of
Collaboration IP and Joint Collaboration IP in accordance with, and subject to, the terms of Section 8.1; 
 (b) discuss material
issues regarding the Prosecution and Maintenance, enforcement and defense of EPIZYME Patents, CELGENE Collaboration Patents, CELGENE Provided Compound Patents, and Joint Collaboration Patents; and 

(c) such other responsibilities as may be assigned to the Patent Committee pursuant to this Agreement or as may be mutually agreed by the
Parties from time to time. 
 For clarity, the Patent Committee shall not have any authority beyond the specific matters set forth in this
Section 4.5.3, and in particular shall not have any power to amend, modify or waive compliance with the terms of this Agreement or to alter, increase, expand or waive compliance by a Party with, a Party’s obligations under this Agreement.
In any case where a matter within the Patent Committee’s authority arises, the Patent Committee shall convene a meeting and consider such matter within [**] days after the matter is first brought to the Patent Committee’s attention, or, if
earlier, at the next scheduled Patent Committee meeting. 
 4.5.4 Minutes. The Patent Liaison from the Party other than the
Party of the chairperson of the Patent Committee shall be responsible for preparing and circulating minutes of each meeting setting forth, inter alia, an overview of the discussions at the meeting and a list of any actions, decisions or
determinations approved by the Patent Committee, and a list of any issues to be resolved by the Executive Officers pursuant to Section 4.5.5. Such minutes shall be effective only after approved by both Parties in writing. With the sole
exception of specific items of the meeting minutes to which the members cannot agree and that are escalated to the 

  
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Executive Officers as provided in Section 4.5.5, definitive minutes of all meetings shall be finalized no later than [**] days after the meeting to which the minutes pertain. If, at any time
during the preparation and finalization of the minutes, the Parties do not agree on any issue with respect to the minutes, such issue shall be resolved by the escalation process set forth in Section 4.5.5. The decision resulting from the
escalation process shall be recorded by the Patent Liaison in amended finalized minutes for such meeting. 
 4.5.5 Decisions. All
decisions of the Patent Committee shall be made by consensus, with each Party having one vote. If the Patent Committee cannot agree on a matter within the Patent Committee’s authority within [**] days after it has met and attempted to reach
such decision, then, either Party may, by written notice to the other, have such issue referred to the Executive Officers for resolution. The Parties’ respective Executive Officers shall meet within [**] Business Days after such matter is
referred to them, and shall negotiate in good faith to resolve the matter. If the Executive Officers are unable to resolve the matter within [**] days after the matter is referred to them, then the decision shall be resolved as set forth below: 

(a) IP Ownership. The Patent Committee shall determine ownership of Collaboration IP and Joint Collaboration IP in accordance with and
subject to the terms of Section 8.1; provided that the Patent Committee may allocate ownership of a particular item of intellectual property to improve the prospects of obtaining patent protection with respect to such item of
intellectual property, even if such allocation is not in accordance with the terms of Section 8.1, so long as the Parties mutually agree to such allocation. In the event the Patent Committee cannot agree on a matter regarding ownership of an
item of intellectual property, and the Executive Officers are unable to resolve such matter, then such dispute shall be resolved by a Third Party patent counsel selected by the Patent Committee who (and whose firm) is not, and was not at any time
during the [**] years prior to such dispute, an employee, consultant, legal advisor, officer, director or stockholder of, and does not have any conflict of interest with respect to, either Party. Such patent counsel shall determine ownership of such
intellectual property (i) if such intellectual property is Chemistry IP, in accordance with Section 8.1 and (ii) if such intellectual property is Collaboration IP or Joint Collaboration IP other than Chemistry IP, in accordance with
U.S. patent law. Expenses of the patent counsel shall be shared equally by the Parties. 
 (b) Patent Prosecution. The Patent
Committee shall discuss material issues and provide input to each other regarding the Prosecution and Maintenance, enforcement and defense of EPIZYME Patents, CELGENE Collaboration Patents, CELGENE Provided Compound Patents and Joint Collaboration
Patents. The Patent Liaisons shall be responsible for coordinating the implementation of each Party’s strategies for the protection of the foregoing intellectual property rights related to Licensed Compounds, Licensed Products and Diagnostic
Products; provided that such strategy for both Parties shall require the filing and prosecution of divisional Patent applications as set forth in Section 8.2.4(b) (the foregoing referred to herein as the “Patent
Strategy”). All final decisions related to the Prosecution and Maintenance, enforcement or defense of any EPIZYME Patent, CELGENE Collaboration Patent, CELGENE Provided Compound Patent and Joint Collaboration Patent shall be made by the
Party with the right to control such Prosecution and Maintenance, enforcement or defense, as applicable, as set forth in Article 8. 

  
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 4.6 Alliance Managers. Under the Original Agreement, the Parties each appointed an
individual to act as alliance manager for such Party (each, an “Alliance Manager”), and such Alliance Managers shall continue in such capacity under this Agreement. The Alliance Managers shall be the primary point of contact for the
Parties regarding the activities contemplated by this Agreement and shall facilitate all such activities hereunder, including preparing and finalizing minutes of the JRC and JDC meetings. The Alliance Managers shall attend all meetings of the JRC
and JDC and shall be responsible for assisting the JRC and JDC in performing its oversight responsibilities. The name and contact information for each Party’s Alliance Manager, as well as any replacement(s) chosen by EPIZYME or CELGENE, in
their sole discretion, from time to time, shall be promptly provided to the other Party in accordance with Section 13.8. 
 4.7
Assigned Activities. Notwithstanding anything to the contrary in this Agreement and any assignment or decision by the JRC or JDC, as applicable, with respect to the following, at any time during the Term, (a) CELGENE may accept or reject
any activities assigned or allocated to it in any Research Plan in its sole discretion; (b) CELGENE may accept or reject any activities assigned or allocated to it on any Development Plan, in its sole discretion, prior to CELGENE’s
exercise of the applicable Phase 1 Option related to such Compound (including Licensed Compound) or Licensed Product in the applicable Development Program; and (c) either Party may accept or reject any activities assigned or allocated to it on
any Development Plan, in its sole discretion, after CELGENE’s exercise of the applicable Phase 1 Option related to such Compound (including Licensed Compound) or Licensed Product in the applicable Development Program; provided
that, such rejecting Party may not refuse to (y) conduct any activities it previously agreed to conduct in the applicable Development Plan, and (z) pay its share of the Development Costs as otherwise provided in this Agreement. 

ARTICLE 5 
 LICENSE
GRANTS 
 5.1 License Grants To CELGENE. Subject to the terms and conditions of this Agreement: 

5.1.1 Research Grant to CELGENE. During the Option Term, EPIZYME hereby grants to CELGENE the co-exclusive (with EPIZYME and its
Affiliates), worldwide, royalty-free right and license in the Field, with the right to grant sublicenses (subject to Section 5.1.6), under EPIZYME IP and EPIZYME’s interest in Joint Collaboration IP solely to permit CELGENE to conduct its
activities with respect to Available Targets and Selected Targets, as applicable, and Compounds Directed to such Available Targets and Selected Targets, and related Diagnostic Products, as contemplated under the Research Plan as part of the
Collaboration in accordance with the terms of this Agreement. 
 5.1.2 License upon IND Option Exercise. On an Available
Target-by-Available Target basis, commencing upon the exercise of the IND Option by CELGENE with respect to an 

  
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Available Target, and continuing until such Available Target becomes a Selected Target or such Available Target becomes a Lapsed Target, EPIZYME hereby grants to CELGENE an exclusive right and
license (even as to EPIZYME and its Affiliates, but subject to EPIZYME’s right to practice EPIZYME IP and Joint Collaboration IP to perform its responsibilities hereunder) in the Field, in the EU with respect to [**] and worldwide (except for
the U.S.) with respect to SMYD 2 and SMYD 3, with the right to grant sublicenses (subject to Section 5.1.6), under the EPIZYME IP and EPIZYME’s interest in the Joint Collaboration IP, solely to the extent necessary to Manufacture, have
Manufactured and Commercialize (but not to research or Develop) any and all Licensed Compounds and Licensed Products, in each case Directed to such Available Target, and related Diagnostic Products. 

5.1.3 Licensed Products in the CELGENE Territory. Commencing upon each Target becoming a Selected Target and continuing during the
remainder of the Term (and until such later time as provided in Article 12, if applicable), EPIZYME hereby grants to CELGENE an exclusive right and license (even as to EPIZYME and its Affiliates, except as provided in Section 5.2.4 and
Section 5.4) in the Field in the CELGENE Territory, with the right to grant sublicenses (subject to Section 5.1.6), under the EPIZYME IP and EPIZYME’s interest in the Joint Collaboration IP, solely to the extent necessary to research,
Develop, Manufacture, have Manufactured, use, offer for sale, sell, import and otherwise Commercialize any and all Licensed Compounds and Licensed Products, in each case Directed to such Selected Target, and related Diagnostic Products. 

5.1.4 Licensed Product Development and Manufacturing in the EPIZYME Territory. Commencing upon each Target becoming a Selected Target
and continuing during the remainder of the Term (and until such later time as provided in Article 12, if applicable), with respect to Selected Targets that are [**] and/or DOT1L, EPIZYME hereby grants to CELGENE a co-exclusive (with EPIZYME and its
Affiliates) right and license in the Field in the EPIZYME Territory, with the right to grant sublicenses (subject to Section 5.1.6), under the EPIZYME IP and EPIZYME’s interest in the Joint Collaboration IP and CELGENE retains a
co-exclusive (with EPIZYME and its Affiliates) right and license in the Field in the EPIZYME Territory under the CELGENE IP and CELGENE’s interest in the Joint Collaboration IP, to (i) conduct activities with respect to such Selected
Targets as contemplated under the Development Plans, and (ii) Develop, Manufacture, have Manufactured and import, in the case of the foregoing clauses (i) and (ii), solely to support Development and Commercialization in the CELGENE
Territory, any and all Licensed Compounds and Licensed Products, in each case Directed to such Selected Targets, and related Diagnostic Products; and 

5.1.5 Lapsed Targets and Terminated Targets. Subject to Section 7.1, on a Lapsed Target-by-Lapsed Target and Terminated
Target-by-Terminated Target basis, EPIZYME hereby grants to CELGENE a royalty-free, worldwide, perpetual, non-exclusive right and license, with the right to grant sublicenses (subject to Section 5.1.6), under (a) the EPIZYME Collaboration
IP that is not Chemistry IP and (b) EPIZYME’s interest in the Joint Collaboration Non-Chemistry IP, solely to the extent necessary to research, Develop, Manufacture, have Manufactured, use, offer for sale, sell, import and otherwise
Commercialize Compounds Directed to such Lapsed Target or Terminated Target, as applicable, and related Diagnostic Products. 

  
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 5.1.6 CELGENE’s Sublicensing Rights. Subject to Section 7.1, CELGENE shall have
the right to grant sublicenses under the rights granted to it under Sections 5.1.1 through 5.1.5 inclusive, without the prior written consent of EPIZYME to any of CELGENE’s Affiliates and to Third Party subcontractors engaged by CELGENE in the
ordinary course of business. CELGENE shall also have the right to grant sublicenses under the rights granted to it under Sections 5.1.1 through 5.1.5 inclusive, without the prior written consent of EPIZYME, to any CELGENE Affiliate or Third Party;
provided however that CELGENE shall provide EPIZYME with (a) [**] days written notice prior to executing any such sublicense agreement with a Third Party in any or all of the Major License Countries and (b) a
fully-executed copy of any agreement (redacted as necessary to protect confidential or commercially sensitive information) reflecting any such sublicense promptly after the execution thereof. Each sublicense granted by CELGENE under this
Section 5.1.6 shall be subject to and consistent with the terms and conditions of this Agreement. CELGENE shall remain primarily liable for, and shall guarantee the performance of, its Affiliates and Sublicensees with respect to any sublicense
granted pursuant to this Section 5.1.6. 
 5.1.7 UNC Agreement. 

(a) The license grants by EPIZYME to CELGENE set forth in this Section 5.1 include, as applicable to Available Targets, Selected Targets
and Compounds (including Licensed Compounds) and Licensed Products Directed to such Targets, the sublicense of certain rights licensed to EPIZYME under the UNC Agreement. CELGENE’s rights and licenses under, or with respect to, such sublicense
rights are subject to the restrictions, limitations and obligations imposed on or applicable to EPIZYME’s sublicensees set forth in Articles 6 (excluding Sections 6.2 and 6.3) and 11 and Sections 2.4, 2.5, 2.6, 2.7, 2.8, 4.2, 4.3, 9.2, 9.3,
9.4, 12.1.1, 12.1.3, 12.4, 12.5 and 12.7 of the UNC Agreement. Further, CELGENE acknowledges the disclaimer of warranty and limitation of liability set forth in Article 10 of the UNC Agreement. 

(b) Any obligations required by the UNC Agreement to be included in a sublicense thereunder as set forth in Section 5.1.7(a) above,
shall, with respect to the applicable Available Targets, Selected Targets and Compounds (including Licensed Compounds) and Licensed Products Directed to such Targets, be deemed to be included in this Agreement and shall be further included by
CELGENE in any sublicense granted by CELGENE under this Agreement with respect to such Available Targets, Selected Targets and Compounds (including Licensed Compounds) and Licensed Products Directed to such Targets. 

(c) Without limiting Section 11.1 of this Agreement, in no event will CELGENE, its Affiliates or Sublicensees be responsible or liable
for any payment or indemnification obligations for which EPIZYME is responsible or liable pursuant to the UNC Agreement. 

  
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 5.2 License Grants to EPIZYME. Subject to the terms and conditions of this Agreement: 

5.2.1 Research Grant to EPIZYME. During the Option Term, CELGENE hereby grants to EPIZYME the co-exclusive (with CELGENE and its
Affiliates), worldwide, royalty-free right and license in the Field, with the right to grant sublicenses (subject to Section 5.2.6), under CELGENE IP and CELGENE’s interest in the Joint Collaboration IP solely to permit EPIZYME to conduct
its activities with respect to Available Targets and Selected Targets, as applicable, and Compounds Directed to such Available Targets and Selected Targets, and related Diagnostic Products, as contemplated under the Research Plan as part of the
Collaboration in accordance with the terms of this Agreement. 
 5.2.2 Licensed Products in the EPIZYME Territory. Commencing upon
each Available Target becoming a Selected Target and continuing during the remainder of the Term (and until such later time as provided in Article 12, if applicable), solely with respect to Selected Targets that are [**] and/or DOT1L, CELGENE hereby
grants to EPIZYME a royalty-free, exclusive right and license (even as to CELGENE and its Affiliates, except as provided in Section 5.1.4 and Section 5.4) in the Field in the EPIZYME Territory, with the right to grant sublicenses (subject
to Section 5.2.6), under the CELGENE IP that is not Chemistry IP and CELGENE’s interest in the Joint Collaboration IP, solely to the extent necessary to research, Develop, Manufacture, have Manufactured, use, offer for sale, sell, import
and otherwise Commercialize Licensed Compounds and Licensed Products, in each case Directed to such Selected Target, and related Diagnostic Products. 

5.2.3 CELGENE Provided Compounds. 

(a) Directed to Selected Targets. 

(i) Products in the EPIZYME Territory. Commencing upon the date that a Compound is a CELGENE Development Candidate and continuing
during the remainder of the Term (and until such later time as provided in Article 12, if applicable), solely with respect to any such CELGENE Development Candidate that is Directed to a Selected Target that is DOT1L or [**], CELGENE hereby grants
to EPIZYME a royalty-free right and license in the Field in the EPIZYME Territory, with the right to grant sublicenses (subject to Section 5.2.6), under the CELGENE Provided Compound IP, (A) on an exclusive basis (even as to CELGENE and
its Affiliates, except as provided in Section 5.1.4 and Section 5.4), solely to the extent necessary to Develop, use, offer for sale, sell, import and otherwise Commercialize (in each case, other than to Manufacture and have Manufactured),
and (B) on a non-exclusive basis, solely to the extent necessary to Manufacture and have Manufactured, in each case, such CELGENE Development Candidate and products comprising such CELGENE Development Candidate, in each case Directed to such
applicable Selected Target, and related Diagnostic Products. 
 (ii) Product Development and Manufacturing in the CELGENE Territory.
Commencing upon the date that a Compound is a CELGENE Development Candidate and continuing during the remainder of the Term (and until such later time as provided in Article 12, 

  
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if applicable), solely with respect to any such CELGENE Development Candidate that is Directed to a Selected Target that is DOT1L or [**], CELGENE hereby grants to EPIZYME a royalty-free,
co-exclusive (with CELGENE and its Affiliates) right and license in the Field in the CELGENE Territory, with the right to grant sublicenses (subject to Section 5.2.6), under the CELGENE Provided Compound IP, to (i) conduct activities with
respect to such Selected Targets as contemplated under the Development Plans, and (ii) Develop, Manufacture, have Manufactured and import, in the case of the foregoing clauses (i) and (ii), solely to support Development and
Commercialization in the EPIZYME Territory, such CELGENE Development Candidate and products comprising such CELGENE Development Candidate, in each case Directed to such applicable Selected Target, and related Diagnostic Products; provided
that any such license under CELGENE Provided Compound IP to Manufacture and have Manufactured such CELGENE Development Candidate and products comprising such CELGENE Development Candidate and related Diagnostic Products shall be non-exclusive
rather than co-exclusive and shall be limited solely to the extent necessary to Manufacture and have Manufactured such CELGENE Development Candidate and products comprising such CELGENE Development Candidate and related Diagnostic Products. 

(b) Directed to Lapsed Targets and Terminated Targets. On a Lapsed Target-by-Lapsed Target and Terminated Target-by-Terminated Target
basis, CELGENE hereby grants to EPIZYME a royalty-free, worldwide, perpetual, right and license in the Field, with the right to grant sublicenses (subject to Section 5.2.6), under the CELGENE Provided Compound IP existing as of, and to the
extent used at, the time such Target becomes a Lapsed Target or Terminated Target, as applicable, (A) on an exclusive basis (even as to CELGENE and its Affiliates, except as provided in Section 5.1.4 and Section 5.4), solely to the
extent necessary to Develop, use, offer for sale, sell, import and otherwise Commercialize (in each case, other than to Manufacture and have Manufactured), and (B) on a non-exclusive basis, solely to the extent necessary to Manufacture and have
Manufactured, in each case, the applicable CELGENE Development Candidate(s) and products comprising such CELGENE Development Candidate(s), in each case Directed to the applicable Lapsed Target or Terminated Target, and related Diagnostic Products.

 5.2.4 Licensed Products Development and Manufacturing in the CELGENE Territory. Commencing upon the Effective Date with respect to
DOT1L and commencing on the date, if any, that [**] becomes a Selected Target, and continuing during the remainder of the Term (and until such later time as provided in Article 12, if applicable), CELGENE hereby grants to EPIZYME a royalty-free,
co-exclusive (with CELGENE and its Affiliates) right and license in the Field in the CELGENE Territory, with the right to grant sublicenses (subject to Section 5.2.6), under the CELGENE IP that is not Chemistry IP and CELGENE’s interest in
the Joint Collaboration IP and EPIZYME retains a co-exclusive (with CELGENE and its Affiliates) right and license in the Field in the CELGENE Territory under the EPIZYME IP and EPIZYME’s interest in the Joint Collaboration IP, to
(i) conduct activities with respect to such Selected Targets as contemplated under the Development Plans, and (ii) Develop, Manufacture, have Manufactured and import, in the case of the foregoing clauses (i) and (ii), solely to
support Development and Commercialization in the EPIZYME Territory, any and all Licensed Compounds and Licensed Products, in each case Directed to such applicable Selected Target, and related Diagnostic Products. 

  
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 5.2.5 Lapsed Targets and Terminated Targets. On a Lapsed Target-by-Lapsed Target and
Terminated Target-by-Terminated Target basis, CELGENE hereby grants to EPIZYME a royalty-free, worldwide, perpetual, non-exclusive right and license, with the right to grant sublicenses (subject to Section 5.2.6), under (a) the CELGENE
Collaboration IP that is not Chemistry IP and (b) CELGENE’s interest in the Joint Collaboration Non-Chemistry IP, solely to the extent necessary to research, Develop, Manufacture, have Manufactured, use, offer for sale, sell, import and
otherwise Commercialize Compounds Directed to such Lapsed Target or Terminated Target, as applicable, and related Diagnostic Products. 

5.2.6 EPIZYME’s Sublicensing Rights. Subject to Section 7.1, EPIZYME shall have the right to grant sublicenses under the
rights granted to it under Sections 5.2.1 through 5.2.5 inclusive, without the prior written consent of CELGENE to any of EPIZYME’s Affiliates and to Third Party subcontractors engaged by EPIZYME in the ordinary course of business. EPIZYME
shall also have the right to grant sublicenses under the rights granted to it under Sections 5.2.1 through 5.2.5 inclusive, without the prior written consent of CELGENE, to any EPIZYME Affiliate or Third Party; provided however
that EPIZYME shall provide CELGENE with (a) [**] days written notice prior to executing any such sublicense agreement with a Third Party in any country in the EPIZYME Territory and (b) a fully executed copy of any agreement
(redacted as necessary to protect confidential or commercially sensitive information) reflecting any such sublicense promptly after the execution thereof. Each sublicense granted by EPIZYME under this Section 5.2.6 shall be subject to and
consistent with the terms and conditions of this Agreement. EPIZYME shall remain primarily liable for, and shall guarantee the performance of, its Affiliates and Sublicensees with respect to any sublicense granted pursuant to this
Section 5.2.6. 
 5.3 Licenses to CELGENE Lead Candidates. On a CELGENE Development Candidate-by-CELGENE Development Candidate
basis, in the event CELGENE exercises the applicable Phase 1 Option, then within [**] days after the expiration of the applicable Selection Term, CELGENE shall determine whether to continue to research and Develop within the Collaboration any
Compound(s) other than the CELGENE Development Candidate that (a) are based upon or derived from the CELGENE Provided Compound from which such CELGENE Development Candidate is based upon or derived, (b) are Directed to the same Selected
Target to which the CELGENE Development Candidate is Directed, and (c) as of the date of expiration of the applicable Selection Term, met the Lead Candidate Criteria pursuant to Section 2.3.4, but did not meet the Development Candidate
Selection Criteria pursuant to Section 2.3.5. In the event CELGENE determines to include any such Compound(s) in the applicable Development Program, CELGENE shall provide written notice to EPIZYME, which shall list the identity(ies) and
chemical structure(s) of such Compound(s); it being understood and agreed that no information or data relating to such Compound other than its identity and chemical structure is required to be disclosed or provided by CELGENE under this Agreement.
As of the date of such notice, (w) such Compound shall be deemed a “CELGENE Lead Candidate”, (x) such CELGENE Lead Candidate shall be available for further research and Development under the


  
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Research Plan or applicable Development Plan for the applicable Selected Target, (y) each Party shall grant and hereby does grant the other Party a co-exclusive (with the other Party and its
Affiliates), worldwide, royalty-free right and license in the Field, with the right to grant sublicenses (subject to Section 5.1.6 or 5.2.6, as applicable) under the EPIZYME IP and EPIZYME’s interest in Joint Collaboration IP or the
CELGENE IP and CELGENE’s interest in Joint Collaboration IP, as applicable, solely to permit the other Party to conduct its activities with respect to such CELGENE Lead Candidate as contemplated under the Research Plan or applicable Development
Plan as part of the Collaboration in accordance with the terms of this Agreement; and (z) the licenses set forth in Section 5.2.3 shall become effective on the date a Compound based upon or derived from such CELGENE Lead Candidate, which
is identified, synthesized or otherwise discovered during the conduct of the Collaboration, satisfies the applicable Development Candidate Selection Criteria or is otherwise deemed to be a Development Candidate pursuant to Section 2.3.5 and
shall continue for the remainder of the Term (and until such later time as provided in Article 12, if applicable) and, following such date on which such Compound satisfies the applicable Development Candidate Selection Criteria or is otherwise
deemed to be a Development Candidate pursuant to Section 2.3.5, such Compound shall be deemed to be a CELGENE Development Candidate and a Development Candidate and shall no longer be a CELGENE Lead Candidate, and therefore shall not be eligible
for the Lead Candidate Product milestones set forth in Section 6.5.4. For the avoidance of doubt, any Compound (1) based upon or derived from a CELGENE Lead Candidate, (2) identified, synthesized or otherwise discovered during the
conduct of the applicable Development Program after the applicable Selection Term, and (3) that is determined to satisfy the Lead Candidate Criteria pursuant to Section 2.3.4 during the conduct of the applicable Development Program after
the applicable Selection Term, shall be deemed a “CELGENE Lead Candidate” as of the date of such determination for purposes of subclauses (x), (y) and (z) in the preceding sentence and subclause (z) of Section 1.77.

 5.4 Rights Retained by the Parties. For purposes of clarity, each Party retains the right under Know-How and Patents Controlled by
such Party to the extent necessary to exercise its rights and perform its obligations under this Agreement, and any rights of EPIZYME or CELGENE, as the case may be, not expressly granted to the other Party pursuant to this Agreement shall be
retained by such Party. For the avoidance of doubt and notwithstanding anything to the contrary in this Agreement, [**] under this Agreement. In addition, subject to the exclusivity obligations set forth in Section 7.1, EPIZYME retains the
right, under Patents and Know-How Controlled by EPIZYME, including its interest in Joint Collaboration IP, to perform ongoing platform discovery activities. 

5.5 Section 365(n) of the Bankruptcy Code. All rights and licenses granted pursuant to any section of this Agreement are, and
shall be deemed to be, rights and licenses to “intellectual property” (as defined in Section 101(35A) of title 11 of the United States Code and of any similar provisions of applicable Laws under any other jurisdiction (the
“Bankruptcy Code”)). Each Party agrees that the other Party, as a licensee of rights and licenses under this Agreement, shall retain and may fully exercise all of its rights and elections under the Bankruptcy Code. The Parties
further agree that, in the event of the commencement of a bankruptcy proceeding by or against a Party under the Bankruptcy Code or analogous provisions 

  
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of applicable Law outside the United States, the other Party shall be entitled to a complete duplicate of (or complete access to, as appropriate) any intellectual property licensed to such Party
and all embodiments of such intellectual property, which, if not already in such Party’s possession, shall be promptly delivered to it (a) upon any such commencement of a bankruptcy proceeding upon such Party’s written request
therefor, unless the Party in the bankruptcy proceeding elects to continue to perform all of its obligations under this Agreement or (b) if not delivered under clause (a), following the rejection of this Agreement by the Party in the bankruptcy
proceeding upon written request therefor by the other Party. 
 5.6 Technical Transfer and Disclosure of Know-How. EPIZYME promptly
shall provide to CELGENE access to, and copies of all documents and materials containing the EPIZYME Know-How and EPIZYME Collaboration Know-How as shall be reasonably requested by CELGENE as necessary or reasonably useful to exercise its rights
under the license grants in Section 5.1: (a) in order to undertake mutually agreed activities assigned to CELGENE under the Research Plan and Development Plan(s) or (b) to conduct clinical Development of Licensed Compounds and
Licensed Products. Any Development Costs of materials transferred to CELGENE pursuant to this Section 5.6 shall be borne by the Parties in accordance with Section 6.3 or Section 6.4, as applicable. 

ARTICLE 6 
 FINANCIAL
TERMS 
 6.1 Amendment Fee. In consideration for the amendments to the Original Agreement made hereunder, CELGENE shall pay
EPIZYME a non-refundable, non-creditable payment of Ten Million Dollars ($10,000,000) within [**] days after the Effective Date. Such payment shall be payable by wire transfer of immediately available funds in accordance with Section 6.8. 

6.2 Research Funding During the Selection Term. On an Available Target-by-Available Target basis, during the applicable Selection Term,
(a) EPIZYME shall be solely responsible for all costs incurred by EPIZYME and its Affiliates in performing activities pursuant to the Research Plan and (b) CELGENE shall be solely responsible for all costs incurred by CELGENE and its
Affiliates in performing activities pursuant to the Research Plan. 
 6.3 Development Funding. 

6.3.1 Overview. CELGENE shall be responsible for all of its costs and expenses incurred in the performance of any Development
Activities with respect to a CELGENE Development Program from and after CELGENE’s exercise of the Phase 1 Option relating to such CELGENE Development Program. On a Shared Development Program-by-Shared Development Program basis, except for any
Territory-Specific Development Costs to be paid by the applicable Party pursuant to Section 6.4 and subject to Sections 2.5 and 2.6, during the applicable Development Term, (a) EPIZYME shall pay all DOT1L Phase 1 Costs incurred by EPIZYME
in performing activities related to DOT1L pursuant to the applicable Development Plan; and (b) all other Global Development Costs incurred by the Parties shall be borne fifty percent (50%) by EPIZYME and fifty percent (50%) by CELGENE
(the “Development Cost Share”); provided that, notwithstanding anything to the contrary in this Agreement, all costs 

  
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incurred by EPIZYME through the completion of the first Phase 1 Clinical Trial with respect to an applicable Compound in the United States or Europe (y) during and after expiration of the
Option Term shall be borne by EPIZYME, except as set forth in Section 6.3.1(z), and (z) after the later of the expiration of the Option Term or the completion of the first Phase 1 Clinical Trial with respect to the applicable Compound,
shall be borne fifty percent (50%) by EPIZYME and fifty percent (50%) by CELGENE, solely with respect to any back-up Compound mutually agreed upon by the Parties for t/he applicable Selected Target. Global Development Costs shall initially
be borne by the Party incurring the cost or expense, subject to reimbursement as provided in Section 6.3.2(d). 
 6.3.2 Annual
Budgets; Payment and Reconciliation of Global Development Costs. 
 (a) On a Shared Development Program-by-Shared Development Program
basis, subject to Sections 2.5 and 2.6, no later than [**] days following the beginning of the Development Term and by December 31st of each Calendar Year thereafter, the Parties (acting
through the JDC) shall mutually agree to an appropriate budget (or an appropriate amendment or update to the then-current budget) under the Development Plan for such Shared Development Program to cover Global Development Costs expected to be
incurred by EPIZYME and CELGENE in the performance of Development activities under such Development Plan during the upcoming Calendar Year (or pro rata portion thereof, as applicable) during the applicable Development Term, provided
that with respect to any Clinical Trial(s) or other material Development activities which may take longer than one year to complete, the budget shall cover all Global Development Costs expected to be incurred until the anticipated completion
of such Clinical Trial(s) or other material Development activities (collectively, the “Budgeted Costs”). 
 (b) Each Party
shall calculate and maintain records of Global Development Costs incurred by it in accordance with procedures to be established by the JDC. 

(c) Within [**] days following the end of each Calendar Quarter, each Party shall provide the other Party a report, on a Shared Development
Program-by-Shared Development Program basis, of actual Global Development Costs incurred by such Party during such Calendar Quarter in accordance with the applicable Development Plans, in a manner that allocates such Global Development Costs to the
extent possible to a specific activity in the applicable budget, together with reasonable supporting evidence of such Global Development Costs. 

(d) Reimbursement of Global Development Costs. The Party that incurs less than its share of the total actual Global Development Costs
shall pay to the other Party a payment amount calculated so that each of the Parties bears its Development Cost Share after giving effect to such payment for such Calendar Quarter. 

6.4 Territory-Specific Development Costs. Territory-Specific Development Costs relating solely to the CELGENE Territory shall be borne
one hundred percent (100%) by CELGENE. Territory-Specific Development Costs relating solely to the EPIZYME Territory 

  
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shall be borne one hundred percent (100%) by EPIZYME. In the event the Parties do not agree as to whether a Development Cost is a Territory-Specific Development Cost or a Global Development
Cost, then the Party that desires to conduct the relevant Development activity shall pay [**] percent ([**]%) of such Development Cost. [**] following the commencement of, and until the completion of, the applicable Development activity, the Party
not conducting such Development activity may request that the Party conducting such Development activity provide a summary of the current status of such Development activity, the Development Costs incurred to date, any significant milestones
achieved and any topline initial results of such Development activity. If a Party (the “Non-Paying Party”) wishes to use the results of such Development activity paid for, as between the Parties, solely by the other Party (the
“Sole Paying Party”) as part of a data package submitted by the Non-Paying Party to obtain approval for the same or a similar use of the applicable Licensed Compound or Licensed Product for which the Sole Paying Party conducted such
Development activity (a “Registrational Use”), the Non-Paying Party shall provide written notice thereof and promptly thereafter the Sole Paying Party shall provide the Non-Paying Party with an invoice for [**] percent ([**]%) of
the Development Costs incurred by the Sole Paying Party in the generation of such results as of the date of the Non-Paying Party’s written notice and the Non-Paying Party shall pay such invoice within [**] days. Thereafter, the Non-Paying Party
and Sole Paying Party shall each pay fifty percent (50%) of any additional Development Costs directly arising from such Development activity. For purposes of clarity, merely referencing the existence of the Sole Paying Party’s Development
activities or providing data from such activities to meet safety reporting obligations with respect to the applicable Licensed Compound or Licensed Product by the Non-Paying Party shall not constitute use pursuant to this Section 6.4, but the
incorporation or inclusion of any results of such Development activities by the Non-Paying Party for a Registrational Use shall constitute use for purposes of this Section 6.4. 

6.5 Milestones. 
 6.5.1
[**] Target. Subject to Section 2.4, CELGENE shall make the Development milestone payments to EPIZYME that are set forth below upon the first achievement by EPIZYME, CELGENE, or their respective Affiliates or Sublicensees of the
Development milestone events set forth below with respect to [**], provided that the payment of the first two milestone payments below ((0) and (1)) shall be in CELGENE’s sole discretion; provided further, that, except as provided
in Sections 2.4, if CELGENE fails to pay milestone payment (0) or (1) below, then such Available Target shall be deemed a Lapsed Target for purposes of this Agreement: 

 

					
	 Milestone Event (For [**])
	  	Milestone
Payments
(in $ [**])	 
	 [**]
	  	 	[**	] 
	 [**]
	  	 	[**	] 


  
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	 Milestone Event (For [**])
	  	Milestone
Payments
(in $ [**])	 
	 [**]
	  	 	[**	] 
	 [**]
	  	 	[**	] 
	 [**]
	  	 	[**	] 
	 [**]
	  	 	[**	] 
	 [**]
	  	 	[**	] 

 6.5.2 DOT1L. Subject to Section 2.6.2(o), CELGENE shall make the Development milestone payments to
EPIZYME that are set forth below upon the first achievement by EPIZYME, CELGENE, or their respective Affiliates or Sublicensees of the Development milestone events set forth below with respect to DOT1L. 

 

					
	 Milestone Event (For DOT1L)
	  	Milestone
Payments
(in $ [**])	 
	 [**]
	  	 	[**	] 
	 [**]
	  	 	[**	] 
	 [**]
	  	 	[**	] 
	 [**]
	  	 	[**	] 
	 [**]
	  	 	[**	] 

 6.5.3 [**] and [**] Targets. Subject to Section 2.4, CELGENE shall make the Development
milestone payments to EPIZYME that are set forth below upon the first achievement by EPIZYME, CELGENE, or their respective Affiliates or Sublicensees of the Development milestone events set forth below with respect to each of [**] and [**],
provided that the payment of the first two milestone payments below ((0) and (1)) shall be in CELGENE’s sole discretion; provided further, except as provided in Sections 2.4, that if CELGENE fails to pay milestone payment
(0) or (1) below, then such Available Target shall be deemed a Lapsed Target for purposes of this Agreement: 
  

					
	 Milestone Event (For each of [**] and [**])
	  	Milestone
Payments
(in $ [**])	 
	 [**]
	  	 	[**	] 
	 [**]
	  	 	[**	] 
	 [**]
	  	 	[**	] 
	 [**]
	  	 	[**	] 
	 [**]
	  	 	[**	] 


  
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 [**]. 

6.5.4 Development and Sales Milestones for Lead Candidate Products. CELGENE shall make the Development milestone payment and sales
milestone payment to EPIZYME that are set forth below upon the first achievement by CELGENE or its Affiliates or Sublicensees of the Development milestone event and sales milestone event set forth below with respect to any Lead Candidate Product.

  

					
	 Milestone Event (For each Lead Candidate Product)
	  	Milestone Payments
(in $ [**])	 
	 [**]
	  	 	[**	] 
	 [**] Net Sales (for such purposes, substituting Lead Candidate Product for Licensed Product in the definition of Net Sales) worldwide
exceed [**] Dollars ($[**])
	  	 	[**	] 

 [**]. 
 6.5.5
Sales Milestones for [**] and [**]. Subject to Section 2.4, CELGENE shall make the one-time sales milestone payment to EPIZYME that are set forth below upon the first achievement by CELGENE or its Affiliates or Sublicensees of the
sales milestone event set forth below with respect to Licensed Products that are Directed to [**] and [**]: 
  

					
	 Milestone Event (For each of [**] and [**])
	  	Milestone Payments
(in $ [**])	 
	 [**] Net Sales worldwide of all Licensed Products, in the aggregate, that are Directed to the applicable Selected Target, and only that
Selected Target, exceed [**] Dollars ($[**])
	  	 	[**	] 


  
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	 Milestone Event (For each of [**] and [**])
	  	Milestone Payments
(in $ [**])	 
	 [**] Net Sales worldwide of all Licensed Products, in the aggregate, that are Directed to the applicable Selected Target, and only that
Selected Target, exceed [**] Dollars ($[**])
	  	 	[**	] 

 6.5.6 Sales Milestone for EPIZYME Opt-Out of DOT1L. CELGENE shall make the sales milestone payment to
EPIZYME that is set forth below upon the first achievement by CELGENE or its Affiliates or Sublicensees of the milestone event set forth below, with respect to [**] Net Sales of Licensed Products directed to DOT1L if, with respect to the Development
Program for DOT1L, EPIZYME has exercised an EPIZYME Late Stage Opt-Out as follows: 
  

									
	 Milestone Event(For DOT1L)
	  	Milestone Payments
(in $ [**]) if
EPIZYME opted out
during the Pre-
Pivotal Opt-Out
Period, with Respect
to
the Development
Program for DOT1L	 	  	Milestone Payments
(in $ [**]) if
EPIZYME opted out
during the Pre-NDA
Opt-Out
Period,
with Respect to the
Development
Program for DOT1L	 
	 [**] Net Sales in the United States exceed [**] Million ($[**])
	  	 	[**	] 	  	 	[**	] 

 6.5.7 If CELGENE ceases all Development of a particular Licensed Product (“Discontinued
Product”) after having made one or more milestone payments on the achievement of one or more milestone events by such Licensed Product, there shall be no payment due upon the accomplishment of the same milestone event(s) for which such
milestone payments were previously made with any substitute, backup or replacement Licensed Product Directed to the same Selected Target as the Discontinued Product. 

6.5.8 Upon achievement by or on behalf of EPIZYME, its Affiliates or Sublicensees of a milestone event set forth in this Section 6.5,
CELGENE shall pay EPIZYME the corresponding milestone payment within [**] days after receipt of notice of such achievement from EPIZYME. Upon achievement by or on behalf of CELGENE, its Affiliates or Sublicensees of a milestone event set forth in
this Section 6.5, CELGENE shall promptly (but in no event more than [**] Business Days after achievement thereof) notify EPIZYME of such achievement, and CELGENE shall pay EPIZYME the corresponding milestone payment within [**] days after such
achievement. For purposes of clarity, CELGENE only shall be obligated to make a milestone payment corresponding to each of the foregoing events only once for each 

  
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Selected Target under this Section 6.7, regardless of the number of Compounds (including Licensed Compounds) and Licensed Products (or, as applicable, Lead Candidate Products) that achieve
such milestone event or the number of times such milestone event occurs for any specific Compound (including Licensed Compound) or Licensed Product (or, as applicable, Lead Candidate Product). 

6.6 Royalties. 
 6.6.1
Royalties in the CELGENE Territory. 
 (a) Licensed Products Directed to [**]. 

(i) Subject to Sections 2.4 and 2.5, CELGENE shall pay EPIZYME royalties on [**] Net Sales by CELGENE, its Affiliates and Sublicensees in the
CELGENE Territory (provided that if EPIZYME has exercised its EPIZYME Pre-IND Opt-Out, EPIZYME Post-EOP1 Clinical Opt-Out or EPIZYME Late Stage Opt-Out as to [**], for purposes of this Section 6.6.1(a)(i), the CELGENE Territory
shall not include the United States notwithstanding any expansion of the CELGENE Territory resulting from the EPIZYME Pre-IND Opt-Out, EPIZYME Post-EOP1 Clinical Opt-Out or EPIZYME Late Stage Opt-Out), on a Licensed Product-by-Licensed Product
basis, for all Licensed Products Directed to [**], at the royalty rates set forth in the table below: 
  

					
	 [**] Net Sales in the CELGENE Territory (excluding the United States) (For [**])
	  	Incremental
Royalty Rates	 
	 Portion of [**] Net Sales by CELGENE, its Affiliates and Sublicensees less than $[**]
	  	 	[**	]% 
	 Portion of [**] Net Sales by CELGENE, its Affiliates and Sublicensees equal to or greater than $[**] up to but not including
$[**]
	  	 	[**	]% 
	 Portion of [**] Net Sales by CELGENE, its Affiliates and Sublicensees equal to or greater than $[**] up to but not including
$[**]
	  	 	[**	]% 
	 Portion of [**] Net Sales by CELGENE, its Affiliates and Sublicensees equal to or greater than $[**]
	  	 	[**	]% 

 (ii) In the event EPIZYME has exercised its EPIZYME Pre-IND Opt-Out pursuant to Section 2.4, its EPIZYME
Post-EOP1 Clinical Opt-Out pursuant to Section 2.5, or its EPIZYME Late Stage Opt-Out pursuant to Section 2.6, in each case, with respect to [**], in addition to the royalties set forth above (which shall apply to the CELGENE Territory,
excluding the United States), if as a result of such EPIZYME Pre-IND Opt-Out, EPIZYME Post-EOP1 Clinical Opt-Out or EPIZYME Late Stage Opt-Out the CELGENE Territory expands to include the United States, CELGENE shall pay EPIZYME royalties on [**]
Net Sales by CELGENE, its Affiliates and Sublicensees in the United States, on a Licensed Product-by-Licensed Product basis, for all Licensed Products Directed to [**], at the royalty rates set forth in the table below: 

 

					
	 [**] Net Sales in the United States (For [**])
	  	Incremental
Royalty Rates	 
	 Portion of [**] Net Sales by CELGENE, its Affiliates and Sublicensees less than $[**]
	  	 	[**	]% 
	 Portion of [**] Net Sales by CELGENE, its Affiliates and Sublicensees equal to or greater than $[**] up to but not including
$[**]
	  	 	[**	]% 
	 Portion of [**] Net Sales by CELGENE, its Affiliates and Sublicensees equal to or greater than $[**] up to but not including
$[**]
	  	 	[**	]% 
	 Portion of [**] Net Sales by CELGENE, its Affiliates and Sublicensees equal to or greater than $[**]
	  	 	[**	]% 


  
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 (b) Licensed Products Directed to [**] or [**]. Subject to Sections 2.4 and 2.5,
CELGENE shall pay EPIZYME royalties on [**] Net Sales by CELGENE, its Affiliates and Sublicensees on a worldwide basis, on a Licensed Product-by-Licensed Product basis, for all Licensed Products Directed to [**] or [**], at the royalty rates set
forth in the table below: 
  

					
	 [**] Net Sales Worldwide (For each of [**] and [**])
	  	Incremental
Royalty Rates	 
	 Portion of [**] Net Sales by CELGENE, its Affiliates and Sublicensees less than $[**]
	  	 	[**	]% 
	 Portion of [**] Net Sales by CELGENE, its Affiliates and Sublicensees equal to or greater than $[**] up to but not including
$[**]
	  	 	[**	]% 
	 Portion of [**] Net Sales by CELGENE, its Affiliates and Sublicensees equal to or greater than $[**] up to but not including
$[**]
	  	 	[**	]% 
	 Portion of [**] Net Sales by CELGENE, its Affiliates and Sublicensees equal to or greater than $[**]
	  	 	[**	]% 

 (c) Licensed Products Directed to DOT1L. 

(i) CELGENE shall pay EPIZYME royalties on [**] Net Sales by CELGENE, its Affiliates and Sublicensees in the CELGENE Territory
(provided that if EPIZYME has exercised its EPIZYME Post-EOP1 Clinical Opt-Out or EPIZYME Late Stage Opt-Out as to DOT1L, for purposes of this Section 6.6.1(c)(i), the CELGENE Territory shall not include the United States
notwithstanding any expansion of the CELGENE Territory resulting from such EPIZYME Post-EOP1 Clinical Opt-Out or EPIZYME Late Stage Opt-Out), on a Licensed Product-by-Licensed Product basis, for all Licensed Products Directed to DOT1L, at the
royalty rates set forth in the table below: 
  

					
	 [**] Net Sales in the CELGENE Territory (For DOT1L)
	  	Incremental
Royalty Rates	 
	 Portion of [**] Net Sales by CELGENE, its Affiliates and Sublicensees up to but not including $[**]
	  	 	[**	]% 
	 Portion of [**] Net Sales by CELGENE, its Affiliates and Sublicensees equal to or greater than $[**] up to but not including
$[**]
	  	 	[**	]% 
	 Portion of [**] Net Sales by CELGENE, its Affiliates and Sublicensees equal to or greater than $[**]
	  	 	[**	]% 


  
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 (ii) In the event EPIZYME has exercised its EPIZYME Post-EOP1 Clinical Opt-Out pursuant to
Section 2.5, or its EPIZYME Late Stage Opt-Out pursuant to Section 2.6, in each case, with respect to DOT1L, in addition to the royalties set forth above (which shall apply to the CELGENE Territory, excluding the United States), if as a
result of such EPIZYME Post-EOP1 Clinical Opt-Out or EPIZYME Late Stage Opt-Out the CELGENE Territory expands to include the United States, CELGENE shall pay EPIZYME royalties on [**] Net Sales by CELGENE, its Affiliates and Sublicensees in the
United States, on a Licensed Product-by-Licensed Product basis, for all Licensed Products Directed to DOT1L, at the royalty rates set forth in the table below: 
  

					
	 [**] Net Sales in the United States (for DOT1L)
	  	Incremental
Royalty Rates	 
	 Portion of [**] Net Sales by CELGENE, its Affiliates and Sublicensees up to but not including $[**]
	  	 	[**	]% 
	 Portion of [**] Net Sales by CELGENE, its Affiliates and Sublicensees equal to or greater than $[**] up to but not including
$[**]
	  	 	[**	]% 
	 Portion of [**] Net Sales by CELGENE, its Affiliates and Sublicensees equal to or greater than $[**]
	  	 	[**	]% 

 6.6.2 Royalty Term and Adjustments. 

(a) CELGENE’s royalty obligations to EPIZYME under this Section 6.6 shall commence on a country-by-country and Licensed
Product-by-Licensed Product basis on the date of First Commercial Sale by CELGENE, its Affiliates or Sublicensees to a Third Party of the relevant Licensed Product in the relevant country and shall expire on a country-by-country basis and Licensed
Product-by-Licensed Product basis upon the later of the following (the “Royalty Term” for each Licensed Product), as applicable: 

(i) the expiration of Legal Exclusivity with respect to such Licensed Product in such country; or 

(ii) the fifteenth (15th) anniversary of the First Commercial Sale of such Licensed
Product in such country by CELGENE, its Affiliates or Sublicensees. 
 (b) The foregoing provisions of this Section 6.6
notwithstanding, the royalty amounts payable with respect to Net Sales of Licensed Products shall be reduced, on a country-by-country and Licensed Product-by-Licensed Product basis, to [**] percent ([**]%) of the amounts otherwise payable pursuant
to Section 6.6.1 or 6.6.2 during any portion of the Royalty Term when Legal Exclusivity does not apply to such Licensed Product in such country (hereinafter, the “Know-How Royalty”). 

  
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 6.6.3 Royalty Reduction for Comparable Third Party Product Competition. If, on a Licensed
Product-by-Licensed Product, country-by-country and Calendar Quarter-by-Calendar Quarter basis, Comparable Third Party Product Competition is present with respect to such Licensed Product in such country during such Calendar Quarter, then the
royalties payable with respect to Net Sales of such Licensed Product pursuant to Section 6.6.1 or Section 6.6.2 in such country during such Calendar Quarter shall be reduced by either (a) [**] percent ([**]%) in the event market share
is reduced as set forth in Section 1.28(b)(i) or (b) [**] percent ([**]%) in the event market share is reduced as set forth in Section 1.28(b)(ii), in each case, of the royalties otherwise payable pursuant to Sections 6.6.1 and 6.6.2.

 6.6.4 Third Party Payments. 

(a) CELGENE shall be entitled to credit against the royalties due to EPIZYME upon Net Sales of a Licensed Product in a country an amount
equal to [**] percent ([**]%) of the total royalties for Net Sales of such Licensed Product that are paid by CELGENE to Third Parties with respect to license rights to Third Party Patents that Cover the Manufacture, use, offer for sale, sale or
importation of such Licensed Product in such country; provided however that, all such credits pursuant to this Section 6.6.4 shall not reduce the royalties payable to EPIZYME with respect to any Licensed Product in any
country to less than [**] percent ([**]%) of the royalties otherwise due to EPIZYME pursuant to Section 6.6.1 or Section 6.6.2; and provided further that, CELGENE shall have the right to carry forward for application
against royalties payable to EPIZYME with respect to Net Sales of such Licensed Product in such country in future periods any amount that is not so credited due to the limitation in the immediately preceding proviso. 

(b) In the event EPIZYME or any of its Affiliates enters into a Patent or Know-How license with a Third Party that is necessary or useful for
the Manufacture, use, offer for sale, sale or importation of a Licensed Product in a country in the CELGENE Territory after the Effective Date, (it being understood that, except for the UNC Agreement, neither EPIZYME nor any of its Affiliates is a
party to any such relevant Third Party licenses as of the Effective Date), under which EPIZYME or its Affiliate, as applicable, is entitled to grant a sublicense to CELGENE, CELGENE will have the right to obtain such sublicense from EPIZYME or its
Affiliates, as applicable; provided however that, subject to Sections 6.6.4(d) and 

  
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10.4(f), (i) if CELGENE elects to obtain such sublicense, CELGENE would pay [**] percent ([**]%) of the amounts payable to the Third Party on account of such sublicense (either directly to
the Third Party licensor or to EPIZYME or its Affiliate, as applicable, as the Parties shall reasonably agree with the goal of ensuring timely payment to the Third Party) and CELGENE shall be entitled to credit against the royalties due to EPIZYME
upon Net Sales of such Licensed Product in such country an amount equal to [**] percent ([**]%) of the amounts paid by CELGENE (either directly or indirectly through EPIZYME) to such Third Party with respect to such license rights for such Licensed
Product in such country, subject to the same limitations described in the provisos at the end of the immediately preceding subsection (a), and (ii) if CELGENE does not pay [**] percent ([**]%) of the amounts payable to such Third Party on
account of such sublicense to CELGENE, such Third Party Patent or Know-How shall be excluded from the licenses granted to CELGENE hereunder (i.e., if CELGENE does not pay such amounts with respect to sublicenses that would otherwise be granted to
CELGENE under Third Party license(s) entered into by EPIZYME or its Affiliate, as applicable, the corresponding license rights shall not be sublicensed to CELGENE and EPIZYME shall be deemed not to Control such licensed intellectual property for
purposes of the licenses and other rights granted to CELGENE hereunder). 
 (c) In the event CELGENE or any of its Affiliates enters into a
Patent or Know-How license with a Third Party that is necessary or useful for the Manufacture, use, offer for sale, sale or importation of a Licensed Product in the EPIZYME Territory after the Effective Date, (it being understood that neither
CELGENE nor any of its Affiliates is a party to any such relevant Third Party licenses as of the Effective Date), under which CELGENE or its Affiliate, as applicable, is entitled to grant a sublicense to EPIZYME, EPIZYME will have the right to
obtain such sublicense from CELGENE or its Affiliates, as applicable; provided however that, (i) if EPIZYME elects to obtain such sublicense, EPIZYME would pay [**] percent ([**]%) of the amounts payable to the Third Party
on account of such sublicense (either directly to the Third Party licensor or to CELGENE or its Affiliate, as applicable, as the Parties shall reasonably agree with the goal of ensuring timely payment to the Third Party), and (ii) if EPIZYME
does not pay [**] percent ([**]%) of the amounts payable to such Third Party on account of such sublicense to EPIZYME, such Third Party Patent or Know-How shall be excluded from the licenses granted to EPIZYME hereunder (i.e., if EPIZYME does not
pay such amounts with respect to sublicenses that would otherwise be granted to EPIZYME under Third Party license(s) entered into by CELGENE or its Affiliate, as applicable, the corresponding license rights shall not be sublicensed to EPIZYME and
CELGENE shall be deemed not to Control such licensed intellectual property for purposes of the licenses and other rights granted to EPIZYME hereunder). 

(d) Notwithstanding anything to the contrary in this Agreement, in the event EPIZYME enters into a Patent or Know-How license with a Third
Party with respect to U.S. Patent No. [**] or any U.S. or foreign family members of such Patent, after the Effective Date, EPIZYME shall, at EPIZYME’s sole cost and expense, ensure that such Third Party license shall permit EPIZYME to grant a
sublicense to CELGENE, and any intellectual property licensed under such Third Party license shall automatically be deemed to be EPIZYME IP and within the Control of EPIZYME as of the effective date of such Third Party license. For the avoidance of
doubt, Sections 6.6.4(a) - (c), inclusive, including the payment provisions therein, shall not apply with respect to such Third Party license. 

6.6.5 Aggregate Limitation on Deductions. Notwithstanding anything to the contrary herein, under no circumstances shall the combined
effect of all reductions to the royalties payable to EPIZYME under Sections 6.6.2(b), 6.6.3 and 6.6.4, on a country-by-country and Licensed Product-by-Licensed Product basis, reduce the effective royalties payable by CELGENE to EPIZYME pursuant to
this Agreement for any Calendar Quarter below [**] percent ([**]%) of the otherwise applicable royalties payable pursuant to Section 6.6.1. 

  
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 6.7 Reports; Royalty Payments. 

6.7.1 Until the expiration of all applicable Royalty Terms under this Article 6, CELGENE agrees to make written reports to EPIZYME within [**]
days after the end of each Calendar Quarter covering Net Sales of Licensed Products, on a Licensed Product-by-Licensed Product and country-by-country basis in the CELGENE Territory by CELGENE, its Affiliates and Sublicensees during such Calendar
Quarter. The information contained in each report under this Section 6.7 shall be considered Confidential Information of CELGENE. 

6.7.2 Each such written report shall provide Net Sales by country and by Licensed Product for the period in question, adjustments (if any)
made pursuant to Sections 6.6.2(b), 6.6.3, 6.6.4 and 6.6.5 and a calculation of royalties due. 
 6.7.3 Concurrent with the delivery of each
such report, CELGENE shall make the royalty payment, if any, due to EPIZYME under Article 6 for the Calendar Quarter covered by such report. 

6.8 Methods of Payments; Payments Non-Refundable and Non-Creditable. 

6.8.1 All payments due from one Party (the “Payor”) to the other Party (the “Payee”) under this Agreement
shall be paid in Dollars by wire transfer to a bank in the United States designated in writing by the Payee. 
 6.8.2 The payments due from
CELGENE to EPIZYME under Sections 6.1, 6.5 and 6.6 shall be non-refundable and non-creditable (except as permitted under Section 12.7.3); provided that nothing in this Section 6.8.2 shall limit any legal or equitable remedies that CELGENE
may have to seek or recover damages in the event of a breach of this Agreement by EPIZYME. 
 6.9 Accounting. 

6.9.1 Payor agrees to keep, and to require its Affiliates and Sublicensees to keep, full, clear and accurate records for a minimum period of
[**] years after the relevant payment is owed pursuant to this Agreement, setting forth the sales and other disposition of Licensed Products sold or otherwise disposed of in sufficient detail to enable royalties and compensation payable to Payee
hereunder to be determined. 

  
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 6.9.2 Payor further agrees, upon not less than [**] days prior written notice, to permit, and to
require its Affiliates and Sublicensees to permit, the books and records relating to such Licensed Product to be examined by an independent accounting firm selected by Payee and reasonably acceptable to Payor for the purpose of verifying reports
provided by Payor under this Article 6. Such audit shall not be performed more frequently than [**] in any twelve (12)-month period and the sales of a particular Licensed Product in a particular period may not be audited more than [**], and shall be
conducted under appropriate confidentiality provisions, for the sole purpose of verifying the accuracy and completeness of all financial, accounting and numerical information and calculations provided under this Agreement. If the independent
accounting firm is of the view that there is an error in the determination of any payments, the firm shall give Payor reasonable opportunity to confirm the error and if Payor is able to show to the satisfaction of the firm that no error occurred
within [**] days of the firm’s completion of the audit, the firm shall correct its determination. Subject to the above, the firm shall only disclose the results of that audit to Payor and Payee, and shall disclose no other details. All books
and records made available for audit shall be deemed to be Confidential Information of Payor. 
 6.9.3 Such audit examination is to be made
at the expense of Payee, except if the results of the audit reveal an underpayment of royalties or milestone payments under this Agreement of [**] percent ([**]%) or more in any Calendar Year, in which case reasonable audit fees for such audit
examination shall be paid by Payor. 
 6.9.4 When calculating Net Sales, the amount of such sales in foreign currencies shall be converted
into Dollars using the standard methodologies employed by Payor for consolidation purposes. The Payor shall provide reasonable documentation of the calculation and reconciliation of the conversion figures on a Licensed Product-by-Licensed Product
and country-by-country basis as part of its report of Net Sales for the period covered under the applicable report. 
 6.10 Taxes. If
laws or regulations require that taxes be withheld with respect to any payments by Payor to Payee under this Agreement, Payor will: (a) deduct those taxes from the remittable payment, (b) pay the taxes to the proper taxing authority, and
(c) send evidence of the obligation together with proof of tax payment to Payee on a timely basis following that tax payment. Each Party agrees to cooperate with the other Party in claiming refunds or exemptions from such deductions or
withholdings under any relevant agreement or treaty which is in effect. The Parties shall discuss and cooperate regarding applicable mechanisms for minimizing such taxes to the extent possible in compliance with applicable Law. In addition, the
Parties shall cooperate in accordance with applicable Law to minimize indirect taxes (such as value added tax, sales tax, consumption tax and other similar taxes) in connection with this Agreement. Notwithstanding the foregoing provisions of this
Section 6.10, if CELGENE is required by any taxing authority outside of the United States to withhold taxes from any amount payable by CELGENE hereunder, then CELGENE shall give notice to EPIZYME of such requirement and shall pay to EPIZYME
such additional amount as may be necessary so that EPIZYME shall receive, after deduction of such withholding tax, the amount which EPIZYME would have received in the absence of such withholding tax, provided, however that CELGENE shall have no
obligation to pay any additional amount to the extent that the withholding tax would not have 

  
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been imposed but for (i) the failure by EPIZYME to qualify for an exemption from or reduction in the rate of withholding tax under any applicable income tax convention between the United
States and Switzerland, (ii) the assignment by EPIZYME of its rights under this Agreement or any redomiciliation of EPIZYME outside of the United States, or (iii) the assertion by a taxing authority in a jurisdiction other than the United
States or Switzerland that a payment by CELGENE to EPIZYME hereunder is derived from sources within such other jurisdiction and therefore is subject to withholding tax in such other jurisdiction. In addition, If CELGENE assigns its rights and
obligations hereunder to an Affiliate or Third Party outside the United States or Switzerland pursuant to Section 13.5, and if such Affiliate or Third Party shall be required by applicable Law to withhold any additional taxes from or in respect
of any amount payable under this Agreement as a result of such assignment, then any such amount payable under this Agreement shall be increased to take into account the additional taxes withheld as may be necessary so that, after making all required
withholdings, EPIZYME receives an amount equal to the sum it would have received had no such assignment been made. 
 6.11 Late
Payments. Any undisputed amount owed by Payor to Payee under this Agreement that is not paid on or before the date such payment is due shall bear interest at a rate per annum equal to the lesser of the prime or equivalent rate per annum quoted
by The Wall Street Journal, eastern U.S. edition, on the first Business Day after such payment is due, plus [**] percent ([**]%), or the highest rate permitted by applicable Law, calculated on the number of days such payments are paid after such
payments are due and compounded monthly. Interest shall not accrue on undisputed amounts that were paid after the due date as a result of mistaken Payee actions (e.g., if a payment is late as a result of Payee providing an incorrect account for
receipt of payment). In addition, the Payor shall reimburse the Payee for all reasonable costs, including attorneys’ fees and legal expenses, incurred in the collection of late payments; provided however that the foregoing
shall not apply to payments disputed in good faith by the Payor unless the Payee is successful in such dispute or the Payor ceases to dispute such payments. 

6.12 Diagnostic Products. If CELGENE or any of its Affiliates or sublicensees Commercializes a Diagnostic Product under the license
granted to CELGENE pursuant to Section 5.1.3, the Parties shall negotiate in good faith a reasonable royalty to be paid by CELGENE to EPIZYME, taking into account the facts and circumstances at such time, including profitability of such
Diagnostic Product. 
 ARTICLE 7 

EXCLUSIVITY 
 7.1 Target
Exclusivity. 
 7.1.1 During the Option Term. Except pursuant to this Agreement, during the Option Term, neither Party nor any of
its respective Affiliates shall, except as otherwise permitted in Section 7.1.3, either (a) alone or with or for any Third Party, research (including screen), Develop, Manufacture (for research, Development or Commercialization), or
Commercialize in the Field any Compound Directed to DOT1L, [**] or [**] or, only if the Phase 1 Option with respect to [**] has been exercised by CELGENE, [**], or (b) grant a license or sublicense to research (including screen), Develop,
Manufacture (for research, Development or 

  
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Commercialization), or Commercialize in the Field any Compound Directed to DOT1L, [**] or [**] or, only if the Phase 1 Option with respect to [**] has been exercised by CELGENE, [**];
provided that this Section 7.1.1 shall not prevent either Party from conducting any Development activities that incur Territory-Specific Development Costs pursuant to Section 6.4 or engaging Third-Party subcontractors in
accordance with Section 2.11. Notwithstanding anything to the contrary in this Section 7.1.1, in the event during the Option Term (y) either Party terminates this Agreement in its entirety, this Section 7.1.1 shall not apply to
either Party; or (z) CELGENE terminates this Agreement as to a Selected Target on a Selected Target-by-Selected Target basis, then with respect to the applicable Terminated Target, this Section 7.1.1 shall not apply to CELGENE and its
Affiliates or to EPIZYME and its Affiliates solely with respect to such Terminated Target. In addition, during the Option Term, neither EPIZYME nor any of its Affiliates shall consummate, or attempt to consummate, a License Event with respect to any
Available Target or Selected Target. 
 7.1.2 After the Option Term. Except pursuant to this Agreement, during the Term, neither
Party nor any of its respective Affiliates shall, except as otherwise permitted in Section 7.1.3, either (a) alone or with or for any Third Party, research (including screen), Develop, Manufacture (for research, Development or
Commercialization), or Commercialize in the Field any Compound Directed to a Selected Target, or (b) grant a license or sublicense to research (including screen), Develop, Manufacture (for research, Development or Commercialization), or
Commercialize in the Field any Compound Directed to a Selected Target or (c) alone or with or for any Third Party, or grant a license or sublicense to, research (including screen), Develop, Manufacture (for research, Development or
Commercialization), or Commercialize in the Field any Licensed Compound that is Directed to a Selected Target for any Target other than the applicable Selected Target; provided that this Section 7.1.2 shall not prevent either
Party from conducting any Development activities that incur Territory-Specific Development Costs pursuant to Section 6.4 or engaging Third-Party subcontractors in accordance with Section 2.11. For purposes of clarity, this
Section 7.1.2 shall apply only to Selected Targets and shall not apply to any Target that is not a Selected Target and any Compound Directed to such Target, including Lapsed Targets and Terminated Targets, and any Compound Directed to any of
the foregoing, and, after the Option Term, nothing shall limit either Party’s or its Affiliates’ right to research (including screen), Develop, Manufacture, or Commercialize in the Field any Compound Directed to a Target that is not a
Selected Target, whether alone or with or for any Third Party, or to grant a license or sublicense in connection with any of the foregoing. Notwithstanding anything to the contrary in this Section 7.1.2 and for the avoidance of doubt, after the
Option Term and during the Term, each Party may engage Sublicensees in accordance with Article 5. 
 7.1.3 Exceptions. 

(a) Business Acquisitions. Notwithstanding Sections 7.1.1 and 7.1.2, if (i) a Business Combination occurs with respect to either
Party with a Third Party that has a material pharmaceutical program other than programs directed to DOT1L and Available Targets or (ii) a Party acquires a Third Party that has a material pharmaceutical program other than programs directed to
DOT1L and Available Targets (including by a merger or consolidation) so 

  
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that such Third Party becomes an Affiliate over which the acquiring Party has control (as defined in Section 1.2), or (iii) a Party acquires all or substantially all of the assets of a
Third Party (including any Subsidiaries or divisions thereof) that has a material pharmaceutical program other than programs directed to DOT1L and Available Targets (each of (i), (ii) and (iii), a “Business Acquisition”; such
Party, the “Business Party”), and, in each case, the Third Party (or any of such Third Party’s then-existing Affiliates) already has, or the acquired assets contain, as applicable, a program that existed prior to, or was
planned prior to and is demonstrably to be implemented shortly after, the Business Acquisition that would otherwise violate Section 7.1.1 or Section 7.1.2 at the time of such Business Acquisition (a “Business Program”),
then such Third Party (or such Third Party’s Affiliate) or the Business Party, as applicable, shall be permitted to continue such Business Program after such Business Acquisition and such continuation shall not constitute a violation of
Section 7.1.1 or Section 7.1.2 above; provided however that (A) none of the EPIZYME IP, CELGENE IP, Joint Collaboration IP, or other Patents or Know-How Controlled by the other Party and, in each case, licensed to
the Business Party shall be used in the Business Program, and (B) the research or Development activities required under this Agreement shall be conducted separately from any research or Development activities directed to such Business Program,
including the maintenance of separate lab notebooks and records (password-protected to the extent kept on a computer network) and separate personnel working on each of the activities under this Agreement and the activities covered under such
Business Program. The Business Party shall adopt reasonable procedures to limit the dissemination of Sensitive Information to only those personnel having a need to know such Sensitive Information in order for such Business Party and/or the Third
Party, as applicable, to perform its obligations or to exercise its rights under this Agreement, including, in furtherance of the foregoing goal, adoption of reasonable procedures to prohibit and limit the use and disclosure of Sensitive Information
for competitive reasons against the other Party and its Affiliates, including the use of Sensitive Information for the research, Development, Manufacture or Commercialization of Compounds, and to prohibit or limit Sensitive Information from being
disclosed to or used by any person who is also working on or making scientific, intellectual property or commercial decisions regarding Compounds at the time of receipt or use of any Sensitive Information, or within [**] years following receipt or
use of any Sensitive Information. For the purpose of this Section 7.1.3(a), “Sensitive Information” means all Confidential Information of either Party with respect to: the Research Plan or Development Plans; reports or data
provided pursuant to Section 2.10; reports or timelines provided pursuant to Section 3.3; invoice details, royalty related reports or other commercially-sensitive information of the Parties; information related to prosecution efforts of
the Parties or the status of enforcement efforts of the Parties; information related to research, Development, Manufacturing and Commercialization activities in connection with Compounds (including Licensed Compounds) and Licensed Products Directed
to any Target or Selected Target, as applicable. [**]. 
 (b) [**]. Section [**] shall not apply to the continuing conduct of any programs
by CELGENE or its Affiliates (whether alone or with or for any Third Party) to [**]. 
 (c) Lapsed Targets. Nothing in this
Section 7.1 shall limit either Party’s or its Affiliates’ right to, either (i) at any time anywhere in the world, alone or with or for any Third Party, research (including screen), Develop, Manufacture (for research, Development


  
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or Commercialization), or Commercialize in the Field any Compounds (other than Licensed Compounds Directed to Selected Targets) Directed to Lapsed Targets; (ii) at any time anywhere in the
world grant a license or sublicense to any Third Party, to research (including screen), Develop, Manufacture (for research, Development or Commercialization), or Commercialize in the Field any Compounds (other than Licensed Compounds Directed to
Selected Targets) Directed to Lapsed Targets; or (iii) at any time anywhere in the world, perform ongoing platform discovery activities. 

ARTICLE 8 
 OWNERSHIP OF
INTELLECTUAL PROPERTY RIGHTS 
 8.1 Ownership. 

8.1.1 Pre-Existing Patents and Know-How; Intellectual Property Arising Outside of the Collaboration. EPIZYME shall retain all of its
right, title and interest in, to and under the EPIZYME IP existing prior to the Effective Date or arising outside of the Collaboration during the Term, and CELGENE shall retain all of its rights, title and interest in, to and under the CELGENE IP
existing prior to the Effective Date or arising outside of the Collaboration during the Term, except, in each case, to the extent that any such rights are expressly licensed by one Party to the other Party under this Agreement. 

8.1.2 Intellectual Property Arising Under This Agreement. 

(a) Except as otherwise provided in Section 8.1.3(a), CELGENE shall be the sole owner of any Patents and Know-How discovered, developed,
invented, conceived or reduced to practice solely by or on behalf of CELGENE under this Agreement (it being understood that any activities carried out by or on behalf of EPIZYME under this Agreement shall not be construed or interpreted to be
carried out by or on behalf of CELGENE for purposes hereof), and CELGENE shall retain all of its right, title and interest thereto, except to the extent that any rights or licenses are expressly granted thereunder by CELGENE to EPIZYME under this
Agreement. 
 (b) Except as otherwise provided in Section 8.1.3(b), EPIZYME shall be the sole owner of any Patents and Know-How
discovered, developed, invented, conceived or reduced to practice solely by or on behalf of EPIZYME under this Agreement (it being understood that any activities carried out by or on behalf of CELGENE under this Agreement shall not be construed or
interpreted to be carried out by or on behalf of EPIZYME for purposes hereof), and EPIZYME shall retain all of its right, title and interest thereto, except to the extent that any rights or licenses are expressly granted thereunder by EPIZYME to
CELGENE under this Agreement. 
 (c) Any Joint Collaboration Patents and Joint Collaboration Know-How shall be owned jointly by CELGENE and
EPIZYME, and all rights, title and interest thereto shall be jointly owned by the Parties, subject to any rights expressly licensed by one Party to the other Party under this Agreement. Except to the extent either Party is restricted by the licenses
granted by one Party to the other Party pursuant to this Agreement, or the covenants 

  
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contained herein (including in Section 7.1), each Party shall be entitled to practice and license the Joint Collaboration Patents and Joint Collaboration Know-How without restriction and
without consent of, or (subject to the financial provisions of this Agreement) an obligation to account to, the other Party, and each Party hereby waives any right it may have under applicable Laws to require any such consent or accounting. 

8.1.3 Assignment of Improvements and Novel Chemistry IP. 

(a) EPIZYME Background Chemistry IP Improvements; Chemistry IP Inventions. CELGENE shall and hereby does assign and shall cause its
Affiliates to assign, to EPIZYME all of its and their right, title and interest in and to all Chemistry IP discovered, developed, invented, conceived or reduced to practice by or on behalf of CELGENE or its Affiliates or Sublicensees (whether solely
or jointly with EPIZYME or its Affiliates or Sublicensees) solely pursuant to the conduct of activities under the Collaboration that is solely (i) an improvement or modification to, or derivative of, EPIZYME Background Chemistry IP, or
(ii) new and novel Chemistry IP that does not consist of an improvement or modification to, or derivative of, (A) CELGENE Provided Compound IP or (B) of any Compound based upon or derived from any CELGENE Provided Compound, which is
identified, synthesized or discovered during the conduct of the Collaboration, Directed towards the applicable Available Target or Selected Target, as applicable. 

(b) CELGENE Provided Compound IP Improvements. EPIZYME shall and hereby does assign and shall cause its Affiliates to assign, to
CELGENE all of its and their right, title and interest in and to all Chemistry IP discovered, developed, invented, conceived or reduced to practice by or on behalf of EPIZYME or its Affiliates or Sublicensees (whether solely or jointly with CELGENE
or its Affiliates or Sublicensees) solely pursuant to the conduct of activities under the Collaboration that is solely an improvement or modification to, or derivative of, (A) CELGENE Provided Compound IP or (B) of any Compound based upon
or derived from any CELGENE Provided Compound, which is identified, synthesized or discovered during the conduct of the Collaboration, Directed towards the applicable Available Target or Selected Target, as applicable. 

8.2 Prosecution and Maintenance of Patents. The Parties will perform their respective activities under this Section 8.2 in
accordance with the Patent Strategy to the extent reasonably practicable and legally permissible. 
 8.2.1 EPIZYME Patents. 

(a) Subject to Sections 8.2.3 and 8.2.4, as between the Parties, EPIZYME shall have the first right (but not the obligation) to Prosecute and
Maintain the EPIZYME Patents. EPIZYME shall keep CELGENE informed as to material developments with respect to the Prosecution and Maintenance of such Patents, including by providing copies of all substantive office actions or any other substantive
documents that EPIZYME receives from any patent office, including notice of all interferences, reissues, re-examinations, oppositions or requests for patent term extensions. 

(b) EPIZYME shall also provide CELGENE with a reasonable opportunity to substantively comment on Prosecution and Maintenance of EPIZYME
Patents that Cover the Development, Manufacture or Commercialization of any Compound Directed to a Selected Target (including any Licensed Compound, Lead Candidate or Development Candidate), Licensed Product or Diagnostic Product, prior to taking
material actions (including the filing of initial applications), and will in good faith consider any actions recommended by CELGENE. CELGENE shall have the right to review and make comments on and recommendations in relation to the Prosecution and
Maintenance of such Patents; provided however that CELGENE does so promptly and consistent with any applicable filing deadlines. 

  
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 8.2.2 CELGENE Provided Compound Patents; CELGENE Collaboration Patents; Joint Collaboration
Patents. 
 (a) Subject to Sections 8.2.3 and 8.2.4, as between the Parties, CELGENE shall have the first right (but not the
obligation) to Prosecute and Maintain the CELGENE Provided Compound Patents, CELGENE Collaboration Patents and Joint Collaboration Patents. CELGENE shall keep EPIZYME informed as to material developments with respect to the Prosecution and
Maintenance of such CELGENE Provided Compound Patents, CELGENE Collaboration Patents and Joint Collaboration Patents, including by providing copies of all substantive office actions or any other substantive documents that CELGENE receives from any
patent office, including notice of all interferences, reissues, re-examinations, oppositions or requests for patent term extensions. 
 (b)
CELGENE shall also provide EPIZYME with a reasonable opportunity to substantively comment on the Prosecution and Maintenance of the CELGENE Provided Compound Patents, CELGENE Collaboration Patents and Joint Collaboration Patents that Cover the
Development, Manufacture or Commercialization of any Compound Directed to a Selected Target (including any Licensed Compound, Lead Candidate or Development Candidate), Licensed Product or Diagnostic Product, prior to taking material actions
(including the filing of initial applications), and will in good faith consider any actions recommended by EPIZYME. EPIZYME shall have the right to review and make comments on and recommendations in relation to the Prosecution and Maintenance of
such CELGENE Provided Compound Patents, CELGENE Collaboration Patents and Joint Collaboration Patents; provided however that EPIZYME does so promptly and consistent with any applicable filing deadlines. 

8.2.3 Filing Decision or Prosecution Lapse. If, during the Term, the Party with the first right, pursuant to Section 8.2.1 or
8.2.2, to Prosecute and Maintain an EPIZYME Patent, CELGENE Provided Compound Patent, CELGENE Collaboration Patent or Joint Collaboration Patent, as applicable, in any country decides not to file such Patent or intends to allow such Patent to lapse
or become abandoned without having first filed a substitute, the prosecuting or maintaining Party shall notify and consult with the other Party of such decision or intention at least [**] days prior to the date upon which the subject matter of such
Patent shall become unpatentable or such Patent shall lapse or become abandoned, and such other Party shall thereupon have the right (but not the obligation) to assume the Prosecution and Maintenance thereof at its own expense with counsel of its
own choice. Notwithstanding the foregoing, (a) CELGENE shall not have the right pursuant to this Section 8.2.3 to assume the Prosecution and 

  
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Maintenance of any EPIZYME Patent that is not related to any Selected Target, Compound Directed to a Selected Target (including any Licensed Compound, Lead Candidate or Development Candidate),
Licensed Product or Diagnostic Product and (b) EPIZYME shall not have the right pursuant to this Section 8.2.3 to assume the Prosecution and Maintenance of any CELGENE Patent that is not related to any Selected Target, Compound Directed to
a Selected Target (including any Licensed Compound, Lead Candidate or Development Candidate), Licensed Product or Diagnostic Product. 

8.2.4 Cooperation. 
 (a)
Generally. Each Party agrees 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
the Party responsible for the Prosecution and Maintenance of a Patent in accordance with this Section 8.2 to undertake such Prosecution and Maintenance, and shall assist in any license registration processes with applicable governmental
authorities that may be available in the other Party’s territory for the protection of a Party’s interests in this Agreement. In the event of any termination of a Party’s license rights hereunder, the Party with a license registration
related to such terminated license rights shall promptly cooperate with any request by the other Party to terminate any such registration relating to the terminated license rights. 

(b) Regarding the Filing and Prosecution of Divisional Patent Applications. The Parties shall cooperate with one another, through the
Patent Committee and their respective Patent Liaisons, to file and prosecute the CELGENE Provided Compound Patents, CELGENE Collaboration Patents, EPIZYME Patents and Joint Collaboration Patents for which either Party is responsible for Prosecution
and Maintenance pursuant to this Section 8.2, including in the furtherance of the Patent Strategy. At either Party’s request, the Parties shall cooperate with one another to file and prosecute divisional Patent applications with respect to
EPIZYME Patents, CELGENE Provided Compound Patents, CELGENE Collaboration Patents and Joint Collaboration Patents, in each case that are primarily applicable to a Selected Target, Compound Directed to a Selected Target (including any Licensed
Compound, Lead Candidate or Development Candidate), Licensed Product or Diagnostic Product, if practicable and if necessary or desirable to divide subject matter relating to the Development, Manufacture or Commercialization of Licensed Compounds,
Licensed Products or Diagnostic Products from other subject matter. 
 8.3 Patent Costs. Each Party shall be responsible for all
costs and expenses associated with its Prosecution and Maintenance activities under Section 8.2. 
 8.4 Defense of Claims Brought by
Third Parties. If a Party becomes aware of any claim that the research, Development, Manufacture or Commercialization of a Compound (including a Licensed Compound), Licensed Product or Diagnostic Product infringes the intellectual property
rights of any Third Party, such Party shall promptly notify the other Party. In any such instance, the Parties shall as soon as practicable thereafter discuss in good faith regarding the best response to such notice, subject to Article 11. 


  
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 8.5 Enforcement of EPIZYME Patents and CELGENE Patents. 

8.5.1 Duty to Notify of Infringement. If any Party learns of an infringement or threatened infringement by a Third Party with respect
to any CELGENE Patent, EPIZYME Patent or Joint Collaboration Patent, including actual or alleged infringement under 35 USC §271(e)(2) that is or would be competitive with a Licensed Compound, Licensed Product or Diagnostic Product
(“Competitive Infringement”), such Party shall promptly notify the other Party and shall provide such other Party with available evidence of such Competitive Infringement. 

8.5.2 Enforcement of EPIZYME Patents, CELGENE Provided Compound Patents, CELGENE Collaboration Patents and Joint Collaboration Patents in
the EPIZYME Territory. EPIZYME shall have the primary right, but not the obligation, to institute, prosecute, and control any action or proceeding with respect to any Competitive Infringement of EPIZYME Patents, CELGENE Provided Compound
Patents, CELGENE Collaboration Patents and Joint Collaboration Patents in the EPIZYME Territory, by counsel of its own choice, and CELGENE shall have the right, at its own expense, to be represented in such action by counsel of its own choice. If
EPIZYME fails to bring an action or proceeding with respect to a CELGENE Provided Compound Patent, CELGENE Collaboration Patent or Joint Collaboration Patent within a period of [**] days after first being notified of such Competitive Infringement
(or [**] days after being notified in the case of an action brought under the Hatch-Waxman Act), CELGENE shall have the right to bring and control such an action with respect to such CELGENE Provided Compound Patent, CELGENE Collaboration Patent or
Joint Collaboration Patent by counsel of its own choice, and EPIZYME shall have the right to be represented in any such action by counsel of its own choice at its own expense. 

8.5.3 Enforcement of CELGENE Patents, EPIZYME Patents and Joint Collaboration Patents in the CELGENE Territory. CELGENE shall have the
primary right, but not the obligation, to institute, prosecute, and control any action or proceeding with respect to any Competitive Infringement of CELGENE Patents, EPIZYME Patents and Joint Collaboration Patents in the CELGENE Territory, by
counsel of its own choice, and EPIZYME shall have the right, at its own expense, to be represented in such action by counsel of its own choice. If CELGENE fails to bring an action or proceeding with respect to an EPIZYME Patent or Joint
Collaboration Patent within a period of [**] days after first being notified of such Competitive Infringement (or [**] days after being notified in the case of an action brought under the Hatch-Waxman Act (with respect to any Competitive
Infringement related to a Licensed Product for which EPIZYME has exercised its EPIZYME Pre-IND Opt-Out pursuant to Section 2.4, its EPIZYME Post-EOP1 Clinical Opt-Out pursuant to Section 2.5, or its EPIZYME Late Stage Opt-Out pursuant to
Section 2.6) or any ex-U.S. equivalent of the Hatch-Waxman Act), EPIZYME shall have the right to bring and control such an action with respect to such EPIZYME Patent or Joint Collaboration Patent by counsel of its own choice, and CELGENE shall
have the right to be represented in any such action by counsel of its own choice at its own expense. 
 8.5.4 Other Actions. For
purposes of clarity, (a) EPIZYME shall have the sole right, at its own expense, to institute, prosecute, and control any action or proceeding with 

  
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respect to any infringement of the EPIZYME Patents outside of the CELGENE Territory that Cover Licensed Compounds, Licensed Products or Diagnostic Products and worldwide that do not Cover
Licensed Compounds, Licensed Products or Diagnostic Products, by counsel of its own choice; and (b) CELGENE shall have the sole right, at its own expense, to institute, prosecute, and control any action or proceeding with respect to any
infringement of the CELGENE Patents in the CELGENE Territory that Cover Licensed Compounds, Licensed Products or Diagnostic Products and worldwide that do not Cover Licensed Compounds, Licensed Products or Diagnostic Products, by counsel of its own
choice. 
 8.5.5 Settlement. A settlement or consent judgment or other voluntary final disposition of a suit under this
Section 8.5 may be entered into without the consent of the Party not bringing suit; provided however that any such settlement, consent judgment or other disposition of any action or proceeding by a Party under this Article
8 shall not, without the consent of the Party not bringing suit, (a) impose any liability or obligation on such Party, (b) include the grant of any license, covenant or other rights to any Third Party that would conflict with or reduce the
scope of the subject matter included under the exclusive licenses granted to such Party under this Agreement, or (c) conflict with or reduce the scope of the subject matter claimed in any Patent owned (solely or jointly) by the Party not
bringing suit. 
 8.5.6 Cooperation. If one Party brings any such action or proceeding in accordance with this Section 8.5 or
where legally required to initiate or maintain suit or collect damages, the other Party agrees to be joined as a party plaintiff, and to give the first Party reasonable assistance and authority to file and prosecute the suit, all at the first
Party’s cost and expense. 
 8.5.7 Costs and Recoveries. The costs and expenses of the Party bringing suit under this
Section 8.5 shall be borne by such Party, and any damages or other monetary awards recovered shall be shared as follows: 
 (a) the
amount of such recovery actually received by the Party controlling such action shall first be applied to the out-of-pocket costs incurred by each Party in connection with such action; and 

(b) any remaining proceeds shall, in the case of suits with respect to Competitive Infringement relating to a Licensed Compound, Licensed
Product or Diagnostic Product, be allocated between the Parties such that the Party bringing suit under this Section 8.5 retains [**] and the other Party retains [**] of such amount. 

8.6 Regulatory Data Protection. To the extent required or permitted by applicable Law, CELGENE will use Commercially Reasonable Efforts
to promptly, accurately and completely list, with the applicable Regulatory Authorities in the CELGENE Territory during the Term, all applicable Patents for any Licensed Product or related Diagnostic Product that CELGENE intends to, or has begun to,
Commercialize (including with respect to any Licensed Product for which EPIZYME has exercised its EPIZYME Pre-IND Opt-Out pursuant to Section 2.4, its EPIZYME Post-EOP1 Clinical Opt-Out pursuant to Section 2.5, or its EPIZYME Late Stage
Opt-Out pursuant to Section 2.6), such listings to include all so called “Orange Book” 

  
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listings required under the Hatch-Waxman Act, all so called “Patent Register” listings as required in Canada and all similar listings in any other relevant countries. Prior to such
listings, the Parties will meet to evaluate and identify all applicable Patents. Notwithstanding the preceding sentence, CELGENE will retain final decision-making authority as to the listing of all applicable Patents for such Licensed Product or
related Diagnostic Product, regardless of which Party owns such Patent. To the extent required or permitted by applicable Law, CELGENE will use Commercially Reasonable Efforts to promptly request or apply for any other available Regulatory-Based
Exclusivity for any Licensed Product or related Diagnostic Product that CELGENE intends to, or has begun to, Commercialize (including with respect to any Licensed Product for which EPIZYME has exercised its EPIZYME Pre-IND Opt-Out pursuant to
Section 2.4, its EPIZYME Post-EOP1 Clinical Opt-Out pursuant to Section 2.5, or its EPIZYME Late Stage Opt-Out pursuant to Section 2.6). To the extent required or permitted by applicable Law, EPIZYME will use Commercially Reasonable
Efforts to promptly, accurately and completely list, with the applicable Regulatory Authorities in the EPIZYME Territory during the Term, all applicable Patents for any Licensed Product or related Diagnostic Product that EPIZYME intends to, or has
begun to, Commercialize in the EPIZYME Territory (except with respect to any Licensed Product for which EPIZYME has exercised its EPIZYME Pre-IND Opt-Out pursuant to Section 2.4, its EPIZYME Post-EOP1 Clinical Opt-Out pursuant to
Section 2.5, or its EPIZYME Late Stage Opt-Out pursuant to Section 2.6) and that have become the subject of an application for Regulatory Approval submitted to FDA, such listings to include all so called “Orange Book” listings
required under the Hatch-Waxman Act. Prior to such listings, the Parties will meet to evaluate and identify all applicable Patents. Notwithstanding the preceding sentence, EPIZYME will retain final decision-making authority as to the listing of all
applicable Patents for such Licensed Product and related Diagnostic Product in the EPIZYME Territory, regardless of which Party owns such Patent. 

8.7 Patent Term Extensions. EPIZYME and CELGENE shall discuss and seek to reach mutual agreement for which, if any, of the Patents
within the EPIZYME Patents, CELGENE Patents or Joint Collaboration Patents, in each case that Cover Licensed Compounds, Licensed Products or Diagnostic Products, the Parties shall apply to obtain patent term extensions, adjustments, restorations, or
supplementary protection certificates under applicable Laws, based on the best commercial interests of the Licensed Products or Diagnostic Products Covered by such Patents; it being understood and agreed that, (a) if CELGENE seeks a patent term
extension, then EPIZYME agrees to negotiate in good faith with respect to any measures required by applicable Law for CELGENE to obtain such extension, which in no event will involve any reduction in payments to be made to EPIZYME by CELGENE and
(b) if EPIZYME seeks a patent term extension, then CELGENE agrees to negotiate in good faith with respect to any measures required by applicable Law for EPIZYME to obtain such extension, which in no event will involve any reduction in payments
to be made to EPIZYME by CELGENE. If the Parties are unable to reach mutual agreement, EPIZYME shall have the right to make the final decision with respect to EPIZYME Patents, CELGENE Provided Compound Patents, CELGENE Collaboration Patents and
Joint Collaboration Patents that Cover Licensed Products (other than Licensed Products for which EPIZYME has exercised its EPIZYME Pre-IND Opt-Out pursuant to Section 2.4, its EPIZYME Post-EOP1 Clinical Opt-Out pursuant to Section 2.5, or
its EPIZYME Late Stage Opt-Out pursuant to Section 2.6) in the EPIZYME Territory and 

  
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EPIZYME Patents and Joint Collaboration Patents that do not Cover Licensed Products, and CELGENE shall have the right to make the final decision with respect to EPIZYME Patents, CELGENE Patents
and Joint Collaboration Patents that Cover Licensed Products in the CELGENE Territory. 
 8.8 Common Interest Disclosures. With
regard to any information or opinions disclosed pursuant to Section 4.5 or Article 8 by one Party to the other Party regarding Prosecution and Maintenance of EPIZYME IP or CELGENE IP, or enforcement of intellectual property and/or technology by
or against Third Parties, EPIZYME and CELGENE agree that they have a common legal interest in determining the ownership, scope, validity and/or enforcement of EPIZYME IP and CELGENE IP, and whether, and to what extent, Third Party intellectual
property rights may affect the conduct of the Development and Commercialization of any Compound (including Licensed Compound), Licensed Product or Diagnostic Product, and have a further common legal interest in defending against any actual or
prospective Third Party claims based on allegations of misuse or infringement of intellectual property rights relating to the Development, Manufacturing, or Commercialization of any Compound (including Licensed Compound), Licensed Product or
Diagnostic Product. Accordingly, the Parties agree that all such information and materials obtained by the Parties from each other will be used solely for purposes of the Parties’ common legal interests with respect to the conduct of the
Agreement. All such information and materials will be treated as protected by the attorney-client privilege, the work product privilege, and any other privilege or immunity that may otherwise be applicable. By sharing any such information and
materials, neither Party intends to waive or limit any privilege or immunity that may apply to the shared information and materials. Neither Party shall have the authority to waive any privilege or immunity on behalf of the other Party without such
other Party’s prior written consent, nor shall the waiver of privilege or immunity resulting from the conduct of one Party be deemed to apply against any other Party. 

ARTICLE 9 

CONFIDENTIALITY 
 9.1
Confidentiality; Exceptions. Except to the extent expressly authorized by this Agreement, the Parties agree that the receiving Party (the “Receiving Party”) shall keep confidential and shall not publish or otherwise disclose
or use for any purpose other than as provided for in this Agreement any Know-How, Materials or other confidential and proprietary information and materials (whether patentable or otherwise and in any form (written, oral, photographic, electronic,
magnetic, or otherwise)) of the other Party (the “Disclosing Party”) which is disclosed to it by the Disclosing Party under this Agreement or was disclosed to it by the Disclosing Party under the Original Agreement, including trade
secrets, Know-How, inventions or discoveries, proprietary information, formulae, processes, techniques and information relating to a Party’s past, present and future marketing, financial and research or Development activities of any product or
potential product or useful technology of the Disclosing Party and the pricing thereof (collectively, “Confidential Information”), except to the extent that it can be established by the Receiving Party that such Confidential
Information: 
 (a) was in the lawful knowledge and possession of the Receiving Party prior to the time it was disclosed to the Receiving
Party, or was otherwise developed independently by or for the Receiving Party, as evidenced by written records kept in the ordinary course of business, or other documentary proof of actual use by the Receiving Party; 

  
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 (b) was generally available to the public or otherwise part of the public domain at the time of
its disclosure to the Receiving Party; 
 (c) became generally available to the public or otherwise part of the public domain after its
disclosure and other than through any act or omission of the Receiving Party in breach of this Agreement; or 
 (d) was disclosed to the
Receiving Party, other than under an obligation of confidentiality, by a Third Party who, to the knowledge of the Receiving Party, had no obligation to the Disclosing Party not to disclose such information to others. 

Without limitation of Section 2.3.6, EPIZYME shall not disclose any of EPIZYME’s Confidential Information to CELGENE or its AFFILIATES with respect
to any Target that is not an Available Target or Selected Target or any Compounds Directed to any Target that is not an Available Target or Selected Target. If, notwithstanding the foregoing, EPIZYME discloses any such EPIZYME Confidential
Information to CELGENE or any of its Affiliates (other than, for clarity, pursuant to Sections 2.8.3 and 2.8.4), such Confidential Information shall not be considered Confidential Information for purposes of this Agreement and CELGENE and its
Affiliates shall not have any obligation of confidentiality or non-use under Article 9 with respect to such Confidential Information. 
 Notwithstanding
anything to the contrary in this Agreement, a Receiving Party may use any learning, skills, ideas, concepts, techniques, know-how and information, including general chemistry methodologies and general SAR (structure-activity relationship) concepts,
but excluding specific chemical entities synthesized or invented in the conduct of the Collaboration (unless, as to such chemical entities, such use is otherwise permitted by an exception in the foregoing clauses (a), (b), (c) and (d)),
retained in intangible form in the unaided memory of the Receiving Party’s directors, employees, contractors, advisors, agents and other personnel of the Receiving Party who had access to the Disclosing Party’s Confidential Information
(collectively, “Residual Information”) for any purpose, provided that this right to use Residual Information does not represent a license to any Patents Controlled by the Disclosing Party. For purposes of clarity,
nothing contained in the preceding sentence gives the Receiving Party the right to publish or otherwise disclose or use the tangible source of any Residual Information for any purpose other than as provided for in this Agreement. A personnel’s
memory will be considered unaided only if such personnel has not intentionally memorized the information for the purpose of retaining and/or subsequently recording, publishing, disclosing or using it. 

9.2 Authorized Disclosure. Except as expressly provided otherwise in this Agreement, a Receiving Party may use and disclose
Confidential Information of the Disclosing Party as follows: 
 (a) to any Affiliate, Sublicensee or Third Party subcontractor, under
appropriate confidentiality provisions at least as protective as those contained in this Agreement, 

  
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in connection with the performance of its obligations or exercise of rights granted or reserved in this Agreement (including the rights to research, Develop and Commercialize Licensed Products
and Diagnostic Products and to grant licenses and sublicenses hereunder); 
 (b) to the extent such disclosure is reasonably necessary in
filing or Prosecuting or Maintaining Patent applications, prosecuting or defending litigation related to Patents in accordance with this Agreement, complying with applicable governmental regulations, seeking and obtaining Regulatory Approval,
conducting non-clinical activities or Clinical Trials, preparing and submitting INDs to Regulatory Authorities, or is otherwise required by applicable Law; provided however that if a Receiving Party is required by applicable Law
to make any such disclosure of a Disclosing Party’s Confidential Information it will, except where impracticable, give reasonable advance notice to the Disclosing Party of such disclosure requirement and, if requested by the Disclosing Party,
reasonably cooperate with the Disclosing Party to secure confidential treatment of such Confidential Information required to be disclosed; 

(c) in communication with the following Third Parties, in each case on a need to know basis under appropriate confidentiality provisions at
least as protective as those contained in this Agreement: 
 (i) actual or potential investors or lenders; provided that
reasonably in advance of any disclosure by a Party of the identity(ies) of any Selected Target(s), such Party shall notify the other Party in writing of such proposed disclosure; 

(ii) actual acquirors and merger partners and bona fide potential acquirors and merger partners with whom a Party is in active negotiations;
provided that reasonably in advance of any disclosure by such Party of the identity(ies) of any Selected Target(s) to such bona fide potential acquirors and merger partners, such Party shall notify the other Party in writing of such
proposed disclosure, but such Party shall not be required to provide the identity of such actual or potential acquirer or merger partner; 

(iii) actual or potential consultants, legal counsel and accountants; provided that (A) Confidential Information of a
Party shall be disclosed by the other Party solely with respect to those Target(s) that are the subject of such Third Party’s activities and solely to the extent necessary for such Third Party to perform such activities and (B) the
Research Plan will not be shared in its entirety with any such Third Party; and 
 (iv) actual and bona fide potential licensees,
sublicensees and collaborators with whom a Party is in active negotiations with respect to Selected Target(s); provided that (A) Confidential Information of the other Party shall be disclosed solely with respect to the Selected
Target(s) that are the subject of such negotiations and (B) the Research Plan will not be shared in its entirety with any such Third Party; or 

(d) to the extent mutually agreed in writing by the Parties. 

  
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 9.3 Press Release; Disclosure of Agreement. 

9.3.1 Press Release. EPIZYME may issue a press release, in the form attached as Exhibit C, to announce the execution of this
Agreement. Thereafter, except as otherwise set forth in Section 9.3.3, neither Party shall issue any subsequent press release or other public disclosure regarding this Agreement or the subject matter hereof, including the Parties’
activities hereunder, or any results or data arising hereunder, except (a) with the other Party’s prior written consent, which shall not be unreasonably withheld or delayed, or (b) for any disclosure that is reasonably necessary to
comply with applicable securities exchange listing requirements or other applicable Laws; provided however that with respect to clause (b), the announcing Party shall determine, in consultation with legal counsel, whether such
disclosure is required under such securities exchange listing requirements or other applicable Laws, and if so required, shall take reasonable steps to minimize such disclosure while remaining in compliance with such requirements and/or applicable
Laws, in addition to its obligations under Sections 9.2(b) and 9.3.3(a) and (d). 
 9.3.2 Intended Disclosures. Subject to
Section 9.3.1(a) and in accordance with the remainder of this Section 9.3.2, the Parties intend to issue press releases or make other public disclosures with respect to the following matters in their respective Territory: 

(a) the completion of Clinical Trials and top-line results thereof in the applicable Party’s territory; 

(b) commencement of patient enrollments for Clinical Trials in the applicable Party’s territory; 

(c) filings for Regulatory Approval in the applicable Party’s territory; 

(d) Regulatory Approvals in the applicable Party’s territory; and 

(e) milestone achievements and option exercises under this Agreement solely for (i) the clinical and regulatory events set forth in
Sections 9.3.2(a) - (d) above, inclusive, (ii) the exercise of the IND Option by CELGENE with respect to an Available Target, and (iii) the exercise of the Phase 1 Option by CELGENE with respect to a Selected Target. 

Prior to making any such disclosure, the Party proposing such disclosure (the “Proposing Disclosing Party”) shall provide the other Party
(the “Non-Disclosing Party”) with a draft of such proposed disclosure for the Non-Disclosing Party’s review. Within [**] Business Days after the Non-Disclosing Party’s receipt of such proposed disclosure, the Parties shall
discuss any comments the Non-Disclosing Party has to such proposed disclosure and whether such proposed disclosure shall be issued as a joint announcement, and the Parties shall use good faith efforts to agree on the content of such proposed
disclosure. Notwithstanding the foregoing, the Proposing Disclosing Party shall remove any Confidential Information of the Non- Disclosing Party that the Non-Disclosing Party identifies and reasonably requests be removed from such proposed
disclosure. For the avoidance of doubt and without limiting Section 9.3.1(b), such proposed disclosure may not be issued by the Proposing Party without the Non-Disclosing Party’s prior written consent, which shall not be unreasonably
withheld or delayed, and in no event shall the Non-Disclosing Party be required to jointly or solely issue such proposed disclosure. 

  
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 9.3.3 Disclosure of Agreement Terms. 

(a) Each Party agrees to provide to the other Party with a copy of any public announcement regarding this Agreement or the subject matter
hereof, as practicable under the circumstances, reasonably prior to its scheduled release, but in no event less than [**] Business Days. Each Party shall have the right to expeditiously review and recommend changes to any such announcement by the
other Party, and, except as otherwise required by securities exchange listing requirements or applicable Law, the disclosing Party shall remove any Confidential Information of the other Party that the other Party reasonably deems to be inappropriate
for disclosure. 
 (b) Notwithstanding the foregoing, to the extent information regarding this Agreement has already been publicly
disclosed, either Party may subsequently disclose the same information to the public without the consent of the other Party; provided however that such subsequent disclosure does not materially alter the original meaning of the
information disclosed. 
 (c) Each Party shall also be permitted to disclose the terms of this Agreement, in each case under appropriate
confidentiality provisions at least as protective as those contained in this Agreement, to any bona fide actual or potential investors, lenders, acquirors, merger partners, consultants, legal counsel and accountants, licensees, sublicensees or
collaborators on a need to know basis; provided that: 
 (i) subject to Section 9.3.3(c)(ii) and (iii), with respect to
any of the Third Parties listed in Section 9.3.3(c), each Party may only disclose to such Third Party a summary of the material terms of this Agreement relevant to the proposed transaction, the form and substance of such summary to be mutually
agreed upon by the Parties; 
 (ii) with respect to any bona fide actual or potential investors, lenders, acquirors, merger partners,
licensees, sublicensees or collaborators, (A) each Party may provide a redacted version of this Agreement, the form and substance of which shall be sufficient for purposes of reasonable and customary due diligence by such Third Party for the
proposed transaction and mutually agreed upon by the Parties within [**] days of the Effective Date, that will be (1) with respect to investors, lenders, acquirors and merger partners, attached hereto as Exhibit D and (2) with
respect to licensees, sublicensees and collaborators, attached hereto as Exhibit E, in each case, or as amended upon the mutual agreement of the Parties, not to be unreasonably withheld or delayed; and (B) only after negotiations with
such Third Party have progressed so that such Party reasonably and in good faith believes it will execute a definitive agreement with such Third Party with respect to the proposed transaction within the following [**] Business Days may a Party
provide an unredacted version of this Agreement to such Third Party without the other Party’s prior consent; provided that with respect to licensees, sublicensees and collaborators, only the redacted form of this Agreement agreed
pursuant to subsection (A)(2), and not an unredacted version of this Agreement, may be disclosed; and further provided that with respect to [**], this Agreement may not be disclosed in any form to [**], each in its capacity as
an existing licensee and collaborator of EPIZYME; and 
 (iii) with respect to a Party’s legal counsel and accountants, each Party may
provide an unredacted version of this Agreement to such Third Party. 
 (d) Each Party shall give the other Party a reasonable opportunity
to review those portions of all filings with the United States Securities and Exchange Commission (or any stock exchange, including Nasdaq, or any similar regulatory agency in any country other than the U.S.) describing the terms of this Agreement
(including any filings of this Agreement) prior to submission of such filings, and shall give due consideration to any reasonable comments by the non-filing Party relating to such filing, including the provisions of this Agreement for which
confidential treatment should be sought. 

  
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 9.4 Remedies. Each Party shall be entitled to seek, in addition to any other right or
remedy it may have, at Law or in equity, a temporary injunction, without the posting of any bond or other security, enjoining or restraining the other Party from any violation or threatened violation of this Article 9. 

9.5 Publications. 
 9.5.1
Restrictions on Publication. Neither Party nor its Affiliates nor its Sublicensees shall publish or publicly disclose the results generated during the course of performing the Research Plan or Development Plans, or otherwise in the
Development or Commercialization activities directed to any Available Target, Selected Target, Lapsed Target or Terminated Target conducted by either Party under this Agreement without the prior written consent of the other Party, except as
otherwise expressly permitted in this Article 9, including the remainder of this Section 9.5 and Section 9.6, but in all cases subject to the prior review by the other Party for patentability and protection of its Confidential Information
as described in this Section 9.5. Notwithstanding the foregoing, this Section 9.5.1 shall not apply to EPIZYME’s publication or public disclosure of results generated in the course of performing the Research Plan or Development Plans,
or otherwise in the Development or Commercialization activities directed to [**], during any period when CELGENE or any of its Affiliates is engaging in a [**]; provided however, CELGENE may review and comment on such proposed publications, which
comments EPIZYME shall, if timely made, consider in good faith. 
 9.5.2 Submission; Review. The Party seeking to publish or publicly
disclose results hereunder (the “Publishing Party”) shall provide the other Party (the “Reviewing Party”) with a copy of such proposed abstract, manuscript, or presentation no less than [**] days ([**] days in the
case of abstracts) prior to its intended submission for publication or public disclosure. The Reviewing Party shall respond in writing promptly and in no event later than [**] days ([**] days in the case of abstracts or presentations) after receipt
of the proposed material, with one or more of the following: 
 (a) comments on the proposed material, which the Publishing Party shall
consider in good faith; 
 (b) a specific statement of concern, based upon the need to seek patent protection or to block publication or
public disclosure if the Reviewing Party determines that the proposed disclosure is intellectual property that should be maintained as a trade secret to protect a Compound or any research or Development activities conducted under this Agreement; or

 (c) an identification of the Reviewing Party’s Confidential Information that is contained in the material reviewed. 

  
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 Any Confidential Information of the Reviewing Party shall, if requested by the Reviewing Party, be removed. 

9.5.3 Patent and Trade Secret Protection. In the event of concern over patent protection or whether maintaining a trade secret would be
a priority, the Publishing Party agrees not to submit such publication or to make such presentation that contains such information until the Reviewing Party is given a reasonable period of time, and in no event less than [**] days, to seek patent
protection for any material in such publication or presentation which it believes is patentable or to resolve any other issues or to abandon such proposed publication or presentation if the Reviewing Party reasonably determines in good faith that
maintaining such information as a trade secret is a commercially-reasonable priority. 
 9.5.4 Review of Third Party Materials. With
respect to any proposed abstracts, manuscripts or presentations by investigators or other Third Parties conducting activities under the Research Plan or Development Plans with or on behalf of a Party hereunder and who have a right to seek to publish
results or information hereunder to the same extent that CELGENE or EPIZYME (as the case may be) has the right to do so, such materials shall be subject to review by the other Party under this Section 9.5 to the same extent that CELGENE or
EPIZYME (as the case may be) has the right to do so. 
 9.5.5 Available Targets Prior to Selection. Subject to Sections 9.5.6(a) and
(b), EPIZYME shall have the right, with the prior written consent of CELGENE not to be unreasonably withheld or delayed, to publish or publicly disclose results (but not Confidential Information of CELGENE generated outside of the Collaboration)
related to any Available Targets that are not Selected Targets, subject to the submission and review procedure set forth in this Section 9.5, including Section 9.5.2. 

9.5.6 Exceptions. 
 (a)
EPIZYME Opt-Out. In the event EPIZYME exercises its EPIZYME Pre-IND Opt-Out pursuant to Section 2.4, its EPIZYME Post-EOP1 Clinical Opt-Out pursuant to Section 2.5, or its EPIZYME Late Stage Opt-Out pursuant to Section 2.6, the
provisions of this Section 9.5 shall not apply to CELGENE, its Affiliates or Sublicensees, with respect to the applicable Selected Target. 

(b) Lapsed Targets and Terminated Targets. Subject to Section 9.6, as between EPIZYME and CELGENE, only EPIZYME shall have the
right, without the consent of CELGENE, to publish or publicly disclose results (but not Confidential Information of CELGENE generated outside of the Collaboration) related to any Lapsed Targets and Terminated Targets, and EPIZYME shall have the
right to do so (a) in the case of Lapsed Targets 

  
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as to which EPIZYME is in possession of Confidential Information of CELGENE that CELGENE generated outside the Collaboration, subject to the submission and review procedure set forth in this
Section 9.5 and (b) otherwise, without being subject to the submission and review procedure set forth in this Section 9.5 

(c) General Review Articles on Targets. Subject to Sections 9.5.6(a) and (b), EPIZYME shall have the right, without the prior written
consent of CELGENE, to publish scientific articles generally reviewing Targets (but not Confidential Information of CELGENE generated outside of the Collaboration), subject to the submission and review procedure set forth in this Section 9.5.

 9.6 Clinical Trial Register. Notwithstanding anything to the contrary in this Article 9, each of CELGENE and EPIZYME shall have
the right to publish registry information and summaries of data and results from any human Clinical Trials conducted by the applicable Party under this Agreement on its clinical trials registry or on a government-sponsored database such as
www.clinicaltrials.gov or other publicly available websites such as www.clinicalstudyresults.org, without requiring the consent of the other Party. The Parties shall reasonably cooperate if needed in order to ensure the publication of any such
registry information or summaries of data and results from such human Clinical Trials as required on the clinical trial registry of each Party and any government-sponsored database such as www.clinicaltrials.gov or other publicly available websites
such as www.clinicalstudyresults.org. In the event both Parties conducted the applicable human Clinical Trial, the JDC shall determine which Party shall perform such publication. 

ARTICLE 10 

REPRESENTATIONS AND WARRANTIES 

10.1 Representations and Warranties of Both Parties. Each Party hereby represents and warrants to the other Party, as of the Effective
Date, that: 
 (a) Such Party is duly organized, validly existing and in good standing under the Laws of the jurisdiction of its formation
and has full corporate power and authority to enter into this Agreement and to carry out the provisions hereof; 
 (b) Such Party has taken
all necessary action on its part to authorize the execution and delivery of this Agreement and the performance of its obligations hereunder; 

(c) This Agreement has been duly executed and delivered on behalf of such Party, and constitutes a legal, valid, binding obligation,
enforceable against it in accordance with the terms hereof; 
 (d) The execution, delivery and performance of this Agreement by such Party
does not conflict with any agreement or any provision thereof, or any instrument or understanding, oral or written, to which it is a party or by which it is bound, nor violate any applicable Law of any court, governmental body or administrative or
other agency having jurisdiction over such Party; 

  
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 (e) No government authorization, consent, approval, license, exemption of or filing or
registration with any court or governmental department, commission, board, bureau, agency or instrumentality, domestic or foreign, under any applicable Laws currently in effect, is or will be necessary for, or in connection with, the transaction
contemplated by this Agreement or any other agreement or instrument executed in connection herewith, or for the performance by it of its obligations under this Agreement and such other agreements except as may be required to conduct Clinical Trials
or to seek or obtain Regulatory Approvals; and 
 (f) To its knowledge, it has not (i) employed or used and has not used a contractor
or consultant that has employed or used, any individual or entity, including a clinical investigator, institution or institutional review board, debarred or disqualified by the FDA (or subject to a similar sanction by any Regulatory Authority
outside the United States), or, (ii) employed any individual who or entity that is the subject of an FDA debarment or disqualification investigation or proceeding (or similar proceeding by any Regulatory Authority outside the United States), in
the conduct of any pre-clinical activities or clinical studies of Compounds. 
 10.2 Representations and Warranties of EPIZYME.
EPIZYME hereby represents and warrants to CELGENE, as of the Effective Date (except to the extent a different date is indicated below for a particular representation and warranty, in which case such different date and not the Effective Date shall
apply to such representation and warranty), that: 
 (a) Schedule 10.2(a) sets forth a complete and accurate list of all EPIZYME
Patents Controlled by EPIZYME and/or its Affiliates, indicating the owner, licensor and/or co-owner(s), if applicable. Except as set forth on Schedule 10.2(a), EPIZYME and its Affiliates do not own, or have a license to, any Patent that
Covers any Compound or Diagnostic Product, or that otherwise are necessary or useful to research, Develop, Manufacture or Commercialize any Compound or Diagnostic Product; 

(b) Schedule 10.2(b) sets forth a complete and accurate list of all agreements relating to the licensing, sublicensing or other
granting of rights with respect to the EPIZYME IP, any Compound or any Diagnostic Product to which EPIZYME or any of its Affiliates is a party, and EPIZYME has provided complete and accurate copies of all such agreements (other than the GSK
Agreement and the Collaboration and License Agreement, by and between Eisai Co., Ltd. and EPIZYME, dated April 1, 2011) to CELGENE (the “EPIZYME Agreements”). Except under the EPIZYME Agreements, EPIZYME and its Affiliates are
not subject to any payment obligations to Third Parties as a result of the execution or performance of this Agreement. EPIZYME and its Affiliates are not in material breach of any EPIZYME Agreement pursuant to which EPIZYME and/or its Affiliates
receive a license or sublicense to EPIZYME IP (the “EPIZYME In-Licenses”). As between the Parties, EPIZYME shall be solely responsible for any payment obligations to Third Parties pursuant to any EPIZYME Agreement, which if
applicable shall constitute a fully paid-up Additional Payment and therefore EPIZYME is deemed to Control any corresponding licensed intellectual property; 

  
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 (c) EPIZYME has all rights, authorizations and consents necessary to grant all rights and
licenses it purports to grant to CELGENE with respect to the EPIZYME IP under this Agreement; 
 (d) Neither EPIZYME nor any of its
Affiliates has granted any right or license to any Third Party relating to any of the EPIZYME IP that would conflict with or limit the scope of any of the rights or licenses granted to CELGENE hereunder; 

(e) Neither EPIZYME nor any of its Affiliates has granted any liens or security interests on the EPIZYME IP and the EPIZYME IP is free and
clear of any mortgage, pledge, claim, security interest, covenant, easement, encumbrance, lien or charge of any kind; 
 (f) Neither
EPIZYME nor its Affiliates has received any written notice of any claim that any Patent or trade secret right owned or controlled by a Third Party would be infringed or misappropriated by the research, Development, Manufacture, or Commercialization
of Compounds Directed to any Target (including Licensed Compounds), Licensed Products or Diagnostic Products by CELGENE, its Affiliates or Sublicensees as contemplated by this Agreement; 

(g) There are no claims, judgments, settlements, litigations, suits, actions, disputes, arbitration, judicial or legal, administrative or
other proceedings or governmental investigations pending or, to EPIZYME’s knowledge, threatened against EPIZYME which would be reasonably expected to materially affect or restrict the ability of EPIZYME to consummate the transactions
contemplated under this Agreement and to perform its material obligations under this Agreement, or which would affect in a material manner the EPIZYME IP, any Compound or any Diagnostic Product; 

(h) To its knowledge, the EPIZYME IP is not being infringed or misappropriated by any Third Party, other than non-material infringement by
Third Party compound catalogue companies; 
 (i) As of the date of the Original Agreement, to its knowledge, other than U.S. Patent No.
[**], there are no Patents or Know-How owned by a Third Party and not included in the EPIZYME IP that were necessary for the Development, Manufacture or Commercialization of any Compound (including Licensed Compound) or Licensed Product that is
Directed to any Available Target or any Selected Target; 
 (j) [**] has not selected and has no right to select [**] as a Target pursuant
to the [**] Agreement; 
 (k) Any payments to be made to [**] pursuant to the [**] Agreement and [**] pursuant to the [**] Agreement, and
any milestone payments to be made to [**]pursuant to the [**] Agreement, that shall be paid by EPIZYME as a result of receiving the upfront fee from CELGENE as provided in Section 6.1, shall not exceed [**] Dollars ($[**]) in the aggregate; and

 (l) EPIZYME has not materially breached any term or condition of the Original Agreement. 

  
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 10.3 Representations and Warranties of CELGENE. CELGENE hereby represents and warrants to
EPIZYME, as of the Effective Date, that: 
 (a) CELGENE has all rights, authorizations and consents necessary to grant all rights and
licenses it purports to grant to EPIZYME with respect to the CELGENE IP under this Agreement; 
 (b) Neither CELGENE nor any of its
Affiliates has granted any right or license to any Third Party relating to any of the CELGENE IP that would conflict with or limit the scope of any of the rights or licenses granted to EPIZYME hereunder; 

(c) Neither CELGENE nor any of its Affiliates has granted any liens or security interests on the CELGENE IP and the CELGENE IP is free and
clear of any mortgage, pledge, claim, security interest, covenant, easement, encumbrance, lien or charge of any kind; 
 (d) Neither
CELGENE nor its Affiliates has received any written notice of any claim that any Patent or trade secret right owned or controlled by a Third Party would be infringed or misappropriated by the research, Development, Manufacture, or Commercialization
of Compounds Directed to an Available Target or Selected Target (including Licensed Compounds), Licensed Products or Diagnostic Products by CELGENE, its Affiliates or Sublicensees as contemplated by this Agreement; 

(e) There are no claims, judgments, settlements, litigations, suits, actions, disputes, arbitration, judicial or legal, administrative or
other proceedings or governmental investigations pending or, to CELGENE’s knowledge, threatened against CELGENE which would be reasonably expected to materially affect or restrict the ability of CELGENE to consummate the transactions
contemplated under this Agreement and to perform its material obligations under this Agreement, or which would affect in a material manner the CELGENE IP; 

(f) To its knowledge, the CELGENE IP is not being infringed or misappropriated by any Third Party; 

(g) To the knowledge of [**]; and 

(h) CELGENE has not materially breached any term or condition of the Original Agreement. 

  
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 10.4 Mutual Covenants. Except as otherwise set forth below, each Party hereby covenants to
the other Party that: 
 (a) All employees of such Party or its Affiliates or Sublicensees or Third Party subcontractors working under this
Agreement will be under appropriate confidentiality provisions at least as protective as those contained in this Agreement and the obligation to assign all right, title and interest in and to their inventions and discoveries, whether or not
patentable, to such Party as the sole owner thereof; 
 (b) To its knowledge, such Party will not (i) employ or use, nor hire or use
any contractor or consultant that employs or uses, any individual or entity, including a clinical investigator, institution or institutional review board, debarred or disqualified by the FDA (or subject to a similar sanction by any Regulatory
Authority outside the United States) or, (ii) employ any individual who or entity that is the subject of an FDA debarment investigation or proceeding (or similar proceeding by any Regulatory Authority outside the United States), in each of
subclauses (i) and (ii) in the conduct of its activities under this Agreement; 
 (c) Neither Party nor any of its Affiliates
shall, during the Term, grant any right or license to any Third Party relating to any of the intellectual property rights it owns or Controls which would conflict with any of the rights or licenses granted to the other Party hereunder; 

(d) EPIZYME shall maintain the EPIZYME In-Licenses, and shall not amend or terminate such agreements, and will not breach such agreements, if
such modification, termination or breach would materially adversely affect CELGENE’s rights under this Agreement; 
 (e) EPIZYME
shall, upon CELGENE’s request, (i) designate those countries in the CELGENE Territory, if any, in which CELGENE desires patent application(s) to be filed pursuant to Section 8.2 of the UNC Agreement, and (ii) notify CELGENE and
permit CELGENE to elect to continue rights in non-designated countries in the CELGENE Territory for which UNC has filed patent applications, if any, pursuant to Section 8.4 of the UNC Agreement; and 

(f) EPIZYME shall be solely responsible for and shall pay all amounts payable to UNC pursuant to the UNC Agreement, LLS pursuant to the LLS
Agreement and MMRF pursuant to the MMRF Agreement, which payments, at the time of such payment, shall constitute a fully paid-up Additional Payment and therefore EPIZYME is deemed at the time of such payment to Control the corresponding intellectual
property licensed to EPIZYME under the UNC Agreement, if any. 
 10.5 Disclaimer. Except as otherwise expressly set forth in this
Agreement, NEITHER PARTY MAKES ANY REPRESENTATION OR EXTENDS ANY WARRANTY OF ANY KIND, EITHER EXPRESS OR IMPLIED, INCLUDING ANY WARRANTY THAT ANY PATENTS ARE VALID OR ENFORCEABLE, AND EXPRESSLY DISCLAIMS ALL IMPLIED WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. Without limiting the generality of the foregoing, each Party disclaims any warranties with regards to: (a) the success of any study or test commenced under this Agreement, (b) the
safety or usefulness for any purpose of the technology or materials, 

  
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including any Compounds, it provides or discovers under this Agreement; or (c) the validity, enforceability, or non-infringement of any intellectual property rights or technology it provides
or licenses to the other Party under this Agreement. 
 ARTICLE 11 

INDEMNIFICATION; INSURANCE 

11.1 Indemnification by CELGENE. CELGENE shall indemnify, defend and hold harmless EPIZYME and its Affiliates, and its and their
respective directors, officers, employees and agents (collectively, the “EPIZYME Indemnitees”), from and against any and all liabilities, damages, losses, costs and expenses, including the reasonable fees of attorneys and other
professional Third Party advisors and experts (collectively, “Losses”), arising out of or resulting from any and all suits, claims, actions, proceedings or demands brought by a Third Party (“Claims”) based upon:

 (a) the willful misconduct of CELGENE or its Affiliates and its or their respective directors, officers, employees and agents, in
connection with CELGENE’s performance of its obligations or exercise of its rights under this Agreement; 
 (b) any breach of any
representation or warranty or express covenant made by CELGENE under Article 10 or any other provision under this Agreement; or 
 (c) the
research that is conducted by or on behalf of CELGENE (excluding any research carried out by or on behalf of EPIZYME, its Affiliate or Sublicensee hereunder in accordance with the Research Plans), the handling and storage by or on behalf of CELGENE
of any chemical agents or other compounds for the purpose of conducting research by or on behalf of CELGENE, and the Development, Manufacture, and Commercialization by CELGENE, its Affiliate or Sublicensee of any Licensed Compound, Licensed Product
or Diagnostic Product, including (i) any Product Liability claims in the CELGENE Territory, or personal injury, property damage or other damage, and (ii) infringement of any Patent or other intellectual property rights of any Third Party
in the CELGENE Territory, in each case resulting from any of the foregoing activities described in this Section 11.1(c); 
 in each case,
provided however that, such indemnity shall not apply to the extent EPIZYME has an indemnification obligation pursuant to Section 11.2 for such Loss. 

Any Losses as to which CELGENE is required to indemnify EPIZYME pursuant to the foregoing clause (c)(ii) shall be deemed to be royalties paid by CELGENE to
Third Parties with respect to license rights to Third Party Patents or Know-How necessary for the Manufacture, use, offer for sale, sale or importation of the applicable Licensed Product or Diagnostic Product in the applicable country, and for which
the provisions of Section 6.6.4(a) shall apply. 

  
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 11.2 Indemnification by EPIZYME. EPIZYME shall indemnify, defend and hold harmless CELGENE
and its Affiliates, and its and their respective directors, officers, employees and agents (collectively, the “CELGENE Indemnitees”), from and against any and all Losses, arising out of or resulting from any and all Claims based
upon: 
 (a) the willful misconduct of EPIZYME or its Affiliates or its or their respective directors, officers, employees and agents, in
connection with EPIZYME’s performance of its obligations or exercise of its rights under this Agreement; 
 (b) any breach of any
representation or warranty or express covenant made by EPIZYME under Article 10 or any other provision under this Agreement; 
 (c) the
research that is conducted by or on behalf of EPIZYME (excluding any research carried out by or on behalf of CELGENE or its Affiliate or Sublicensee hereunder in accordance with the Research Plan; provided however that the
research which is to be carried out by or on behalf of EPIZYME under the Research Plans hereunder shall not be considered or interpreted to be research carried out by or on behalf of CELGENE or its Affiliate or Sublicensee), the handling and storage
by or on behalf of EPIZYME of any chemical agents or other compounds for the purpose of conducting research by or on behalf of EPIZYME, and the Development, Manufacture, and Commercialization by EPIZYME, its Affiliate or Sublicensee of any Licensed
Compound, Licensed Product or Diagnostic Product, including (i) any Product Liability claims in the EPIZYME Territory, personal injury, property damage or other damage, and (ii) infringement of any Patent or other intellectual property
rights of any Third Party in the EPIZYME Territory, in each case resulting from any of the foregoing activities described in this Section 11.2(c); or 

(d) infringement of U.S. Patent No. [**] or any U.S. or foreign family members of such Patent in connection with the research, Development,
Manufacture and Commercialization of any compounds (including Compounds and Licensed Compounds) and products comprising such compound (including Licensed Products) Directed to DOT1L in connection with this Agreement; 

in each of (a), (b) and (c), provided however that, such indemnity shall not apply to the extent CELGENE has an indemnification
obligation pursuant to Section 11.1 for such Loss. 
 11.3 Procedure and Conditions to Indemnification. 

11.3.1 Notice of Claim. All indemnification claims in respect of any Indemnitee seeking indemnity under this Article 11 will be made
solely by the corresponding Party seeking indemnity hereunder (the “Indemnified Party”). The Indemnified Party shall give the indemnifying party (the “Indemnifying Party”) prompt written notice (an
“Indemnification Claim Notice”) of any Losses or the discovery of any fact upon which such Indemnified Party intends to base a request for indemnification under Section 11.1 or 11.2, as applicable, and in no event will the
Indemnifying Party be liable for any Losses that result from any delay in providing such notice. Notice must contain a description of the Claim and the nature and amount of such Loss (to the extent that the nature and amount of such Loss are known
at such time). Together with the Indemnification Claim Notice, the Indemnified Party will furnish promptly to the Indemnifying Party copies of all notices and documents (including court papers) received by the Indemnified Party in connection with
the Claim. 

  
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 11.3.2 Assumption of Defense. At its option, the Indemnifying Party may assume the defense
of any Claim subject to indemnification as provided for in this Article 11 by giving written notice to the Indemnified Party within [**] days (or until such time provided in any applicable extension to appropriately answer any complaint, if any, but
no longer than [**] days; provided that the Indemnified Party makes all reasonable efforts to obtain any such extension) after the Indemnifying Party’s receipt of an Indemnification Claim Notice, provided however
that (i) the Claim solely seeks monetary damages and (ii) the Indemnifying Party expressly agrees in writing that as between the Indemnifying Party and the Indemnified Party, the Indemnifying Party shall be solely obligated to
satisfy and discharge the Claim in full and is able to reasonably demonstrate that it has sufficient financial resources (the matters described in (i) and (ii), the “Litigation Conditions”). Upon assuming the defense of a Claim
in accordance with this Section 11.3.2, the Indemnifying Party shall be entitled to appoint lead counsel in the defense of the Claim. Should the Indemnifying Party assume the defense of a Claim, except as otherwise set forth in this
Section 11.3.2, the Indemnifying Party shall not be liable to the Indemnified Party for any legal expenses subsequently incurred by such Indemnified Party in connection with the analysis, defense or settlement of the Claim. The Indemnified
Party may, at any time, assume the defense of a Claim if at any time the Litigation Conditions are not satisfied with respect to such Claim. 

11.3.3 Participation. Without limiting Section 11.3.2, any Indemnified Party will be entitled to participate in, but not control,
the defense of a Claim for which it has sought indemnification hereunder and to employ counsel of its choice for such purpose; provided however that such employment will be at the Indemnified Party’s own expense unless
(a) the employment thereof has been specifically authorized by the Indemnifying Party in writing, or (b) the Indemnifying Party has failed to assume and actively further the defense and employ counsel in accordance with Section 11.3.2
(in which case the Indemnified Party will control the defense), or (c) the Indemnifying Party no longer satisfies the Litigation Conditions. 

11.3.4 Consent. With respect to any Losses relating solely to the payment of money damages in connection with a Claim that will not
result in the Indemnified Party’s becoming subject to injunctive or other relief or otherwise adversely affect the business of the Indemnified Party in any manner, and as to which the Indemnifying Party will have acknowledged in writing the
obligation to indemnify the Indemnified Party hereunder, and subject to the Litigation Conditions being satisfied, the Indemnifying Party will have the sole right to consent to the entry of any judgment, enter into any settlement or otherwise
dispose of such Loss, on such terms as the Indemnifying Party, in its reasonable discretion, will deem appropriate (provided however that such terms shall include a complete and unconditional release of the Indemnified Party
from all liability with respect thereto), and will transfer to the Indemnified Party all amounts which said Indemnified Party will be liable to pay prior to the time of the entry of judgment. With respect to all other Losses in connection with
Claims, where the Indemnifying Party has assumed the defense of the Claim in accordance with Section 11.3.2, the Indemnifying Party will have authority to consent to the entry of any judgment, enter into any settlement or otherwise dispose of
such Loss provided it obtains the prior written consent of the Indemnified Party (which consent shall be at the Indemnified Party’s reasonable discretion). The Indemnifying Party that has assumed the defense of the Claim in accordance with
Section 11.3.2 

  
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will not be liable for any settlement or other disposition of a Loss by an Indemnified Party (but in no event to include any court judgment or judicial or administrative order or disposition)
that is reached without the written consent of such Indemnifying Party for such Claim, and no Indemnified Party will admit any liability with respect to, or settle, compromise or discharge, any Claim without first offering to the Indemnifying Party
the opportunity to assume the defense of the Claim in accordance with Section 11.3.2. 
 11.3.5 Cooperation. If the Indemnifying
Party chooses to defend or prosecute any Claim, the Indemnified Party will cooperate in the defense or prosecution thereof and will furnish such records, information and testimony, provide such witnesses and attend such conferences, discovery
proceedings, hearings, trials and appeals as may be reasonably requested in connection with such Claim. Such cooperation will include access during normal business hours afforded to the Indemnifying Party to, and reasonable retention by the
Indemnified Party of, records and information that are reasonably relevant to such Claim, and making employees and agents available on a mutually convenient basis to provide additional information and explanation of any materials provided hereunder,
and the Indemnifying Party will reimburse the Indemnified Party for all of its reasonable out-of-pocket expenses incurred in connection with such cooperation. 

11.3.6 Costs. Except as provided above, the reasonable and verifiable costs and expenses, including fees and disbursements of counsel,
incurred by the Indemnified Party in connection with any Claim will be reimbursed on a Calendar Quarter basis by the Indemnifying Party, without prejudice to the Indemnifying Party’s right to contest the Indemnified Party’s right to
indemnification and subject to refund in the event the Indemnifying Party is ultimately held not to be obligated to indemnify the Indemnified Party. 

11.3.7 Multiple Claims. For the avoidance of doubt, a single suit, action, proceeding or demand may include multiple Claims. In the
event any such suit, action, proceeding or demand requires the defense of both (i) an indemnified Claim for which the Indemnifying Party has assumed the defense in accordance with Section 11.3.2 and (ii) (A) an indemnified Claim
for which the Indemnified Party controls the defense settlement; (B) Claims for which each Party is required to indemnify the other Party; and/or (C) a Claim not subject to indemnification under Section 11.1 or Section 11.2, as
applicable, for which a Party retains the right to control the defense, then (1) the Parties shall reasonably cooperate in the defense and settlement of such Claims (except to the extent where such cooperation would present a conflict of
interest), including as required under Section 11.3.5 and (2) the Indemnifying Party shall only be required to indemnify the Indemnified Party for the Claim(s) that are subject to Indemnification in accordance with Section 11.1 or
Section 11.2, as applicable. For purposes of clarity, a Party shall not be required to seek the consent of the other Party in the settlement of any non-indemnified claim. 

11.4 Insurance. 
 11.4.1
EPIZYME’s Insurance Obligations. EPIZYME shall maintain, at its cost, insurance against liability and other risks associated with its activities and obligations under this Agreement, including its Clinical Trials, the Commercialization
of any Licensed Products by 

  
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EPIZYME and its indemnification obligations hereunder, in such amounts, subject to such deductibles and on such terms as are customary for a company such as EPIZYME for the activities to be
conducted by it under this Agreement; provided that if a Business Combination with respect to EPIZYME has occurred in which EPIZYME is acquired by a pharmaceutical company of comparable or greater size than CELGENE based on the net
sales of such company or CELGENE, as applicable, EPIZYME shall thereafter have the right to self insure against such liability and other risks and shall not be required to furnish to CELGENE evidence of such self-insurance. Subject to the
immediately preceding sentence, EPIZYME shall furnish to CELGENE evidence of such insurance and/or self insurance upon request. 
 11.4.2
CELGENE’s Insurance Obligations. CELGENE shall maintain, at its cost, a program of insurance and/or self insurance against liability and other risks associated with its activities and obligations under this Agreement, including its
Clinical Trials, the Commercialization of any Licensed Products by CELGENE and its indemnification obligations hereunder, in such amounts, subject to such deductibles and on such terms as are customary for a company such as CELGENE for the
activities to be conducted by it under this Agreement. 
 11.5 LIMITATION OF LIABILITY. EXCEPT (A) FOR A BREACH OF ARTICLE 7 OR
ARTICLE 9 OR (B) FOR CLAIMS OF A THIRD PARTY THAT ARE SUBJECT TO INDEMNIFICATION UNDER THIS ARTICLE 11 OR (C) FOR DAMAGES DUE TO THE WILLFUL MISCONDUCT OF THE LIABLE PARTY, NEITHER EPIZYME NOR CELGENE, NOR ANY OF THEIR RESPECTIVE
AFFILIATES OR SUBLICENSEES, WILL BE LIABLE TO THE OTHER PARTY TO THIS AGREEMENT, ITS AFFILIATES OR ANY OF THEIR SUBLICENSEES FOR ANY INDIRECT, INCIDENTAL, CONSEQUENTIAL, SPECIAL OR PUNITIVE DAMAGES OR LOST PROFITS OR ROYALTIES, LOST DATA OR COST OF
PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES, WHETHER LIABILITY IS ASSERTED IN CONTRACT, TORT (INCLUDING NEGLIGENCE AND STRICT PRODUCT LIABILITY), INDEMNITY OR CONTRIBUTION, AND IRRESPECTIVE OF WHETHER THAT PARTY OR ANY REPRESENTATIVE OF THAT PARTY
HAS BEEN ADVISED OF, OR OTHERWISE MIGHT HAVE ANTICIPATED THE POSSIBILITY OF, ANY SUCH LOSS OR DAMAGE. 
 ARTICLE 12 

TERM AND TERMINATION 
 12.1
Term; Expiration. 
 12.1.1 Term. This Agreement shall become effective on the Effective Date and, unless earlier terminated
pursuant to this Article 12, shall remain in effect until it expires (the “Term”) as follows: 
 (a) On a Licensed
Product-by-Licensed Product and country-by-country basis, this Agreement shall expire on the date of the expiration of all applicable Royalty Terms with respect to such Licensed Product in such country; and 

(b) This Agreement shall expire in its entirety upon the expiration of all applicable Royalty Terms under this Agreement with respect to all
Licensed Products in all countries in the CELGENE Territory. 

  
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 12.1.2 Effect of Expiration. After the expiration of the Term pursuant to
Section 12.1.1 above, the following terms shall apply: 
 (a) After expiration of the Term (but not after early termination) with
respect to any Licensed Product in a country in the CELGENE Territory pursuant to Section 12.1.1(a), CELGENE shall have a fully-paid, royalty-free right and license, with the right to grant sublicenses, under the EPIZYME IP and EPIZYME’s
interest in the Joint Collaboration IP, in each case existing as of, and to the extent used at, the time of such expiration, to (i) on an exclusive basis, use, sell, offer to sell and import (in each case, other than to Manufacture and have
Manufactured), and (ii) on a non-exclusive basis, Manufacture and have Manufactured, in each case, such Licensed Product and related Diagnostic Products (if any) in the Field in such country in the CELGENE Territory, for so long as it continues
to do so. 
 (b) After expiration of the Term (but not after early termination) with respect to any Licensed Product in a country in the
EPIZYME Territory pursuant to Section 12.1.1(a), EPIZYME shall have a fully-paid, royalty-free right and license, with the right to grant sublicenses, under CELGENE IP and CELGENE’s interest in the Joint Collaboration IP, in each case
existing as of, and to the extent licensed and used at, the time of such expiration, to continue to (i) on an exclusive basis, use, offer to sell, sell and import (in each case, other than to Manufacture and have Manufactured), and (ii) on
a non-exclusive basis, Manufacture and have Manufactured, in each case, such Licensed Product and related Diagnostic Products (if any) in the Field in such country in the EPIZYME Territory, for so long as it continues to do so. 

(c) After expiration of the Term (but not after early termination) with respect to this Agreement in its entirety pursuant to
Section 12.1.1(b), CELGENE shall have an exclusive, fully-paid, royalty-free right and license, with the right to grant sublicenses, under the EPIZYME IP and EPIZYME’s interest in the Joint Collaboration IP, in each case existing as of,
and to the extent used at, the time of such expiration, to (i) use, offer to sell, sell and import (in each case, other than to Manufacture and have Manufactured), and (ii) on a non-exclusive basis, Manufacture and have Manufactured, in
each case, Licensed Products and related Diagnostic Products (if any) in the Field in the CELGENE Territory, for so long as it continues to do so. 

(d) After expiration of the Term (but not after early termination) with respect to this Agreement in its entirety pursuant to
Section 12.1.1(b), EPIZYME shall have a fully-paid, royalty-free right and license, with the right to grant sublicenses, under CELGENE IP and CELGENE’s interest in the Joint Collaboration IP, in each case existing as of, and to the extent
licensed and used at, the time of such expiration, to continue to (i) on an exclusive basis, use, offer to sell, sell and import (in each case, other than to Manufacture and have Manufactured), and (ii) on a non-exclusive basis,
Manufacture and have Manufactured, in each case, Licensed Products and related Diagnostic Products (if any) in the Field in the EPIZYME Territory, for so long as it continues to do so. 

  
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 12.2 Unilateral Termination by CELGENE. 

12.2.1 Termination of Agreement During Option Term. Subject to Section 2.8.5, CELGENE shall have the right, at its sole
discretion, exercisable at any time during the Option Term to terminate this Agreement in its entirety upon sixty (60) days prior written notice to EPIZYME hereunder. 

12.2.2 Termination During the Term. CELGENE shall have the right, at its sole discretion, exercisable at any time to terminate this
Agreement with respect to one or more Selected Target(s), or in its entirety upon one hundred twenty (120) days prior written notice to EPIZYME hereunder. 

12.3 Termination for Cause. 

12.3.1 Termination for Material Breach. 

(a) Either Party (the “Non-Breaching Party”) may terminate this Agreement (y) in its entirety if during the Option Term
(and with respect to CELGENE, at any time during the Term), or (z) on a Selected Target-by-Selected Target basis if after the Option Term, the other Party (the “Breaching Party”) shall have (A) materially breached or
defaulted in the performance of its obligations in a manner that fundamentally frustrates the transactions contemplated by this Agreement hereunder during the Option Term, or (B) materially breached or defaulted in the performance of its
obligations hereunder with respect to a Selected Target or Licensed Compounds or Licensed Products Directed to a Selected Target or related Diagnostic Products in a manner that fundamentally frustrates the transactions contemplated by this Agreement
with respect to such Selected Target, Licensed Compounds or Licensed Products after the Option Term (each of (A) and (B), a “Material Breach”), and such Material Breach shall have continued for [**] days (or, in the case of a
Material Breach with respect to payment, [**] days) after written notice thereof was provided to the Breaching Party by the Non-Breaching Party, such notice describing the alleged Material Breach. Subject to Section 12.3.2, any such termination
of this Agreement under this Section 12.3.1 shall become effective at the end of such [**] day (or [**] day, as applicable) cure period, unless, to the extent such Material Breach is curable: 

(i) the Breaching Party has cured such Material Breach prior to the expiration of such cure period; or 

(ii) such Material Breach is not susceptible to cure within such cure period even with the use of Commercially Reasonable Efforts, in which
event the Non-Breaching Party’s right to termination shall be suspended only if and for so long as (A) the Breaching Party has provided to the Non-Breaching Party a written plan that is reasonably calculated to effect a cure, (B) such
plan is reasonably acceptable to the Non-Breaching Party, and (C) the Breaching Party commits to and does carry out such plan; provided however that, unless otherwise mutually agreed by the Parties in such plan or as set
forth in Section 12.3.2(b) or (c), in no event shall such suspension of the Non-Breaching Party’s right to terminate extend beyond [**] days after the original cure period. 

(b) The right of either Party to terminate this Agreement in its entirety, or on a Selected Target basis, as provided in this
Section 12.3.1 shall not be affected in any way by such Party’s waiver or failure to take action with respect to any previous Material Breach. 

  
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 Notwithstanding the foregoing provisions of this Section 12.3.1, if the applicable Material Breach is a
breach by either Party of its obligation to use Commercially Reasonable Efforts to perform the activities assigned to such Party under the Development Plan pursuant to Section 3.2 with respect to the applicable Selected Target, the
Non-Breaching Party’s termination right pursuant to this Section 12.3.1 with respect to such Material Breach shall be limited to a termination of this Agreement with respect to such Selected Target. Further, with respect to any Material
Breach by CELGENE of its obligations under this Agreement, EPIZYME’s termination right pursuant to this Section 12.3.1 with respect to such Material Breach shall be limited to a termination of this Agreement with respect to the applicable
Selected Target, only in the country(ies) in which such Material Breach was uncured by CELGENE with respect to the obligations of CELGENE under this Agreement; provided that if such Material Breach by CELGENE is a Material Breach as to
the EU taken as a whole, EPIZYME may terminate this Agreement with respect to the entire EU with respect to the applicable Selected Target. 

12.3.2 Disagreement. If the Parties reasonably and in good faith disagree as to whether there has been a Material Breach, the Party
that seeks to dispute that there has been a Material Breach may contest the allegation in accordance with Section 13.1. The cure period for any allegation made in good faith as to a Material Breach under this Agreement will, subject to
Section 12.3.1, run from the date that written notice was first received by the Breaching Party from the Non-Breaching Party, provided that if: 

(a) such Material Breach (i) solely relates to the payment of amounts owed under this Agreement or (ii) is not a breach of
CELGENE’s obligation to use Commercially Reasonable Efforts pursuant to Section 2.3.2(b), 3.2 or 3.5 or EPIZYME’s obligation to use Commercially Reasonable Efforts pursuant to Section 2.3.2(a), 2.8 or 3.2, and the Breaching Party
disputes that there has been a Material Breach, then the Breaching Party shall provide written notice to the Non-Breaching Party that it disputes such claim of Material Breach, and from the date of receipt of such notice by the Non-Breaching Party
until such time as the dispute has become finally settled, the running of the time periods as to which the Breaching Party must cure such Material Breach shall be suspended as to such breach that is the subject matter of the dispute; 

(b) such Material Breach solely relates to a breach of CELGENE’s obligation to use Commercially Reasonable Efforts pursuant to
Section 2.3.2(b), 3.2 or 3.5, and CELGENE disputes that there has been a Material Breach, then EPIZYME shall have the right to terminate this Agreement as set forth in Section 12.3.1; provided that: 

(i) this Agreement shall not terminate unless (A) CELGENE is given [**] days prior written notice by EPIZYME, labeled as a “notice
of material breach for failure to use commercially reasonable efforts”, of EPIZYME’s intent to terminate, stating the reasons and justification for such termination and recommending steps which EPIZYME believes CELGENE should take to cure
such alleged Material Breach, and (B) CELGENE, or its 

  
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Affiliates or Sublicensees, have not (1) during the [**] day period following such notice, provided EPIZYME with a plan for the Development and/or Commercialization of the applicable
Licensed Compounds, Licensed Products and related Diagnostic Products in the applicable country(ies) using Commercially Reasonable Efforts and (2) during the [**] day period following such notice carried out such plan and cured such alleged
Material Breach by using Commercially Reasonable Efforts to Develop and/or Commercialize such Licensed Compounds, Licensed Products and related Diagnostic Products in such country(ies); 

(ii) if CELGENE disputes in good faith the existence or materiality of an alleged Material Breach specified in a notice provided by EPIZYME
pursuant to Section 12.3.2(b)(i), and if CELGENE provides notice to EPIZYME of such dispute within the [**] days following such notice provided by EPIZYME, EPIZYME shall not have the right to terminate this Agreement unless and until the
existence of such Material Breach has been determined in accordance with Section 13.1. Except as set forth in Section 12.3.2(b)(iii), it is understood and acknowledged that during the pendency of such a dispute, all of the terms and
conditions of this Agreement shall remain in effect and the Parties shall continue to perform all of their respective obligations hereunder; and 

(iii) no milestone payments by CELGENE will be due on milestones achieved, with respect to the applicable country(ies) for which termination
is sought, during the period between the notice of termination under this Section 12.3.2(b) and the effective date of termination; provided however, if CELGENE provides notice of a dispute pursuant to Section 12.3.2(b)(ii) and such dispute
is resolved in a manner in which no termination of this Agreement with respect to such country(ies) occurs, then upon such resolution CELGENE will promptly pay to EPIZYME the applicable milestone payment for each milestone achieved during the period
between the notice of termination under this Section 12.3.2(b) and the resolution of such dispute and interest (in accordance with Section 6.11) from the date such milestone would have been due in accordance with Section 6.5 but for
this Section 12.3.2(b)(iii); and 
 (c) such Material Breach solely relates to a breach of EPIZYME’s obligation to use
Commercially Reasonable Efforts pursuant to Sections 2.3.2(a), 2.8 or 3.2, and EPIZYME disputes that there has been a Material Breach, then CELGENE shall have the right to terminate this Agreement as set forth in Section 12.3.1; provided
that: 
 (i) this Agreement shall not terminate unless (A) EPIZYME is given [**] days prior written notice by CELGENE, labeled
as a “notice of material breach for failure to use commercially reasonable efforts”, of CELGENE’s intent to terminate, stating the reasons and justification for such termination and recommending steps which CELGENE believes EPIZYME
should take to cure such alleged Material Breach, and (B) EPIZYME, or its Affiliates or Sublicensees, have not (1) during the [**] day period following such notice, provided CELGENE with a plan for the Development of the applicable
Licensed Compounds, Licensed Products and related Diagnostic Products using Commercially Reasonable Efforts and (2) during the [**] day period following such notice carried out such plan and cured such alleged Material Breach by using
Commercially Reasonable Efforts to Develop such Licensed Compounds, Licensed Products and related Diagnostic Products; and 
 (ii) if
EPIZYME disputes in good faith the existence or materiality of an alleged Material Breach specified in a notice provided by CELGENE pursuant to Section 12.3.2(c)(i), and if EPIZYME provides notice to CELGENE of such dispute within the [**] days
following such notice provided by CELGENE, CELGENE shall not have the right to terminate this Agreement unless and until the existence of such Material Breach has been determined in accordance with Section 13.1. It is understood and
acknowledged that during the pendency of such a dispute, all of the terms and conditions of this Agreement shall remain in effect and the Parties shall continue to perform all of their respective obligations hereunder. 

  
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 12.4 Termination for Patent Challenges. 

12.4.1 By CELGENE. If CELGENE or any of its Affiliates or Sublicensees: 

(a) commences or otherwise voluntarily determines to participate in (other than as may be necessary or reasonably required to assert a
cross-claim or a counter-claim or to respond to a court request or order or administrative law request or order) any action or proceeding (including any patent opposition or re-examination proceeding), challenging or denying the validity of any
EPIZYME Patent or Joint Collaboration Patent, in each case that is exclusively licensed to CELGENE hereunder, or any claim of any of the foregoing; or 

(b) actively assists any other Person (other than as may be necessary or reasonably required to assert a cross-claim or a counter-claim or to
respond to a court request or order or administrative law request or order) in bringing or prosecuting any action or proceeding (including any patent opposition or re-examination proceeding) challenging or denying the validity of any of such
Patents, in each case that are licensed exclusively to CELGENE hereunder, or any claim thereof (each activity under the foregoing clause (a) or (b), a “CELGENE Patent Challenge”); 

then EPIZYME shall have the right to terminate this Agreement with respect to the Selected Target(s), Lapsed Target(s) or Terminated Target(s), as applicable,
to which the CELGENE Patent Challenge relates, upon thirty (30) days’ written notice to CELGENE; provided however that, EPIZYME’s right to terminate this Agreement under this Section 12.4 shall not apply to
any Affiliate of CELGENE that first becomes an Affiliate of CELGENE after the Effective Date of this Agreement in connection with a Business Acquisition, where such Affiliate of CELGENE was undertaking activities in connection with a CELGENE Patent
Challenge prior to such Business Acquisition; provided however that CELGENE causes such CELGENE Patent Challenge to terminate within [**] days after such Business Acquisition. For the avoidance of doubt, an action by CELGENE in
accordance with Article 8 to amend claims within a pending patent application of EPIZYME during the course of CELGENE’s Prosecution of such pending patent application or in defense of a Third Party opposition shall not constitute a challenge
under this Section 12.4. 
 12.4.2 By EPIZYME. If EPIZYME or any of its Affiliates or Sublicensees: 

(a) commences or otherwise voluntarily determines to participate in (other than as may be necessary or reasonably required to assert a
cross-claim or a counter-claim 

  
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or to respond to a court request or order or administrative law request or order) any action or proceeding (including any patent opposition or re-examination proceeding), challenging or denying
the validity of any CELGENE Patent or Joint Collaboration Patent, in each case that is exclusively licensed to EPIZYME hereunder, or any claim of any of the foregoing; or 

(b) actively assists any other Person (other than as may be necessary or reasonably required to assert a cross-claim or a counter-claim or to
respond to a court request or order or administrative law request or order) in bringing or prosecuting any action or proceeding (including any patent opposition or re-examination proceeding) challenging or denying the validity of any of such
Patents, in each case that are licensed exclusively to EPIZYME hereunder, or any claim thereof (each activity under the foregoing clause (a) or (b), an “EPIZYME Patent Challenge”); 

then CELGENE shall have the right to terminate this Agreement with respect to the Selected Target(s), Lapsed Target(s) or Terminated Target(s), as applicable,
to which the EPIZYME Patent Challenge relates, upon thirty (30) days’ written notice to EPIZYME; provided however that, CELGENE’s right to terminate this Agreement under this Section 12.4 shall not apply to
any Affiliate of EPIZYME that first becomes an Affiliate of EPIZYME after the Effective Date of this Agreement in connection with a Business Acquisition, where such Affiliate of EPIZYME was undertaking activities in connection with an EPIZYME Patent
Challenge prior to such Business Acquisition; provided however that EPIZYME causes such EPIZYME Patent Challenge to terminate within [**] days after such Business Acquisition. For the avoidance of doubt, an action by EPIZYME in
defense of a Third Party opposition shall not constitute a challenge under this Section 12.4. 
 12.5 Termination for
Bankruptcy. 
 12.5.1 EPIZYME Bankruptcy. If EPIZYME makes a general assignment for the benefit of creditors, appoints or suffers
appointment of a receiver or trustee over all or substantially all of its property, files a petition under any bankruptcy or insolvency act or has any such petition filed against it which is not dismissed, discharged, bonded or stayed within ninety
(90) days after the filing thereof, CELGENE may terminate this Agreement in its entirety effective immediately upon written notice to EPIZYME. In connection therewith, the provisions of Section 5.5 shall apply. 

12.5.2 CELGENE Bankruptcy. If CELGENE makes a general assignment for the benefit of creditors, appoints or suffers appointment of a
receiver or trustee over all or substantially all of its property, files a petition under any bankruptcy or insolvency act or has any such petition filed against it which is not dismissed, discharged, bonded or stayed within ninety (90) days
after the filing thereof, EPIZYME may terminate this Agreement in its entirety effective immediately upon written notice to CELGENE. In connection therewith, the provisions of Section 5.5 shall apply. 

  
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 12.6 Effects of Termination. If this Agreement is terminated by either Party, in its
entirety or with respect to one or more Selected Target(s), Lapsed Target(s) or Terminated Target(s), as applicable, the following shall apply: 

12.6.1 Termination by CELGENE pursuant to Section 12.2 or by EPIZYME Pursuant to Section 12.3 or Section 12.5. In the
event of termination by CELGENE pursuant to Section 12.2 or by EPIZYME pursuant to Section 12.3 or Section 12.5, whether in its entirety or with respect to one or more Selected Target(s), (w) such termination of a Selected Target
shall be effective with respect to the entire Development Program for such Selected Target; (x) the applicable Available Target (if the entire Agreement is terminated during the Option Term) or Selected Target shall be deemed a
“Terminated Target” and all Licensed Compounds and Licensed Products Directed to such Terminated Target, and related Diagnostic Products, shall be deemed “Terminated Products,” (y) each country in the CELGENE
Territory terminated by EPIZYME pursuant to Section 12.3 shall be deemed a “Terminated Country” for such Terminated Target or if this Agreement is terminated in its entirety or with respect to a Selected Target (whether by
EPIZYME or CELGENE), all countries in the CELGENE Territory shall be deemed “Terminated Countries” for the applicable Terminated Target(s) and the EPIZYME Territory shall include such Terminated Country(ies) with respect to such Terminated
Target(s), and (z) the following shall apply: 
 (a) License Termination. Except as necessary for CELGENE to comply with
Sections 12.6.1(b), (c), (j) and (k), all licenses granted to CELGENE under Sections 5.1.1, 5.1.2 and 5.1.3 of this Agreement solely with respect to the Terminated Target(s) and Terminated Products in the Terminated Country(ies) shall be
terminated and of no further force and effect. 
 (b) Summary of Activities. Within [**] days after such termination, CELGENE shall
provide to EPIZYME a reasonably accurate summary report of the status and results of its (and its Affiliates’ and Sublicensees’) material research, Development, Manufacturing and Commercialization activities directed to the Terminated
Target(s) prior to the effective date of termination in the Field in the Terminated Country(ies). 
 (c) Transition Assistance.
Without limiting the generality of the remainder of this Section 12.6.1, CELGENE shall use its Commercially Reasonable Efforts, at no cost to EPIZYME, to effect a seamless, timely transition to EPIZYME of all research, Development,
Manufacturing and Commercialization activities and responsibilities with respect to the Terminated Products in the Terminated Country(ies) in accordance with a transition plan to be mutually agreed by the Parties. 

(d) License Survival. The licenses granted to EPIZYME pursuant to Sections 5.2.3(b) and 5.2.5 shall, with respect to such Terminated
Product(s) and Terminated Target(s) in the Terminated Country(ies) (i) become perpetual, irrevocable and fully paid-up, (ii) solely with respect to the licenses granted to EPIZYME pursuant to Section 5.2.5 and in the event this
Agreement is terminated with respect to one or more Selected Target(s) (but not in its entirety) and a Phase 1 Clinical Trial for such Terminated Product(s) has been Initiated, shall be expanded to include CELGENE IP that is not Chemistry IP or
intellectual property under Section 2.4.2(b)(ii)(3) (for such purpose substituting “CELGENE IP” for “CELGENE Collaboration IP” in Section 5.2.5(a)) to the extent existing as of, and licensed and used at, the time of
termination, (iii) be solely under the applicable CELGENE IP and CELGENE’s interest in the Joint Collaboration IP (if applicable), in each case existing as of, and to the extent licensed and used at, the time of termination, and
(iv) survive any such termination. 

  
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 (e) Clinical Development Activities. 

(i) With respect to any ongoing Clinical Trials with respect to the Terminated Country(ies) of Terminated Products for which EPIZYME has not
notified CELGENE prior to the effective date of termination that it wishes to assume responsibility, CELGENE shall, at CELGENE’s cost and expense, complete such Clinical Trials, subject to Section 2.12.1, only with regard to those patients
enrolled at the date of termination and may otherwise cease enrollment and cancel all cancelable expenses relating to such Clinical Trials; and 

(ii) With respect to any ongoing Clinical Trials with respect to the Terminated Country(ies) of Terminated Products for which EPIZYME has
notified CELGENE prior to the effective date of termination that it wishes to assume responsibility, (A) each Party shall cooperate with the other Party to facilitate the orderly transfer to EPIZYME of the conduct of such Clinical Trials as
soon as reasonably practicable after the effective date of termination, (B) until such time as the conduct of such Clinical Trials has been successfully transferred to EPIZYME, CELGENE shall continue to conduct such Clinical Trials, subject to
Section 2.12.1, (C) between the effective date of termination and the date on which the conduct of such Clinical Trials has been successfully transferred to EPIZYME, EPIZYME shall be responsible for, and shall reimburse CELGENE with
respect to, all costs and expenses reasonably incurred by CELGENE in the conduct of such Clinical Trials during the foregoing transition period, and (D) following the date on which the conduct of such Clinical Trials has been successfully
transferred to EPIZYME, EPIZYME shall be solely responsible for all costs and expenses of such ongoing Clinical Trials. 
 (f)
Regulatory Filings. To the extent permitted by applicable Law, CELGENE will promptly assign and transfer to EPIZYME all Regulatory Materials for Terminated Products in the Terminated Country(ies); provided that EPIZYME shall be
responsible for the reasonable and documented Out-of-Pocket Costs incurred by CELGENE. If CELGENE is restricted under applicable Law from assigning or transferring ownership of any of the foregoing items to EPIZYME (including in order to continue to
conduct any transition activities as contemplated in this Section 12.6.1, including the conduct of clinical Development activities, if applicable, pursuant to Section 12.6.1(e)), CELGENE shall grant EPIZYME (or its designee) a right of
reference or use to such item (it being understood that CELGENE shall use Commercially Reasonable Efforts to assign and transfer the same to EPIZYME after the completion of such transition activities). CELGENE shall take all actions reasonably
necessary to effect such assignment and transfer or grant of right of reference or use to EPIZYME, including by making such filings as may be required with Regulatory Authorities in the Terminated Country(ies) that may be necessary to record such
assignment or effect such transfer and, at EPIZYME’s written request, complete any pending regulatory filings in the Terminated Country(ies) with respect to all applicable Terminated Products. 

  
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 (g) No Marketing-Related Materials. No promotional materials Controlled by CELGENE as of
the Effective Date that are used in the marketing, promotion or sale of Terminated Products shall be required to be transferred by CELGENE to EPIZYME. 

(h) Trademarks. If the First Commercial Sale of any Terminated Product(s) has occurred in the Terminated Country(ies) as of the
effective date of termination with respect to such Terminated Product(s), at EPIZYME’s written request, CELGENE will assign to EPIZYME any CELGENE trademark(s) used with respect to such Terminated Product(s) (other than CELGENE’s
company-specific names, such as “CELGENE”) in such Terminated Country(ies), provided however that such trademark(s) are neither (i) used for any other products in CELGENE’s portfolio nor (ii) in
CELGENE’s reasonable opinion confusingly similar to any other trademark used for any other products in CELGENE’s portfolio. 

(i) Transfer of Data. Upon EPIZYME’s written request, CELGENE will promptly assign and transfer to EPIZYME its entire right,
title, and interest in and to all pharmacological, toxicological and clinical test data and results, research data, reports and batch records, safety data and all other data, including CMC-related information, formulation information, chemistry and
biology data, Controlled by CELGENE as of the effective date of termination and generated in the research, Development, Manufacture or Commercialization of the Terminated Product(s), but only to the extent solely pertaining to the Terminated
Product(s) in the Terminated Country(ies) and not being used in or having application to the research, Development, Manufacture or Commercialization of any Licensed Compound or Licensed Product Directed to a Selected Target that is not being
terminated, or any other proprietary compound or product of CELGENE; provided that EPIZYME shall be responsible for the reasonable and documented Out-of-Pocket Costs incurred by CELGENE. 

(j) Contracts. CELGENE shall use Commercially Reasonable Efforts to assign to EPIZYME, to the extent assignable and included in the
transition plan to be agreed by the Parties under Section 12.6.1(c), CELGENE’s rights in Third Party agreements for licenses, services or supplies that are solely used in connection with the research, Development, Manufacture or
Commercialization of Terminated Products in the Terminated Country(ies), including any Third Party manufacturing agreements and clinical trial agreements (subject to Section 12.6.1(e)), in each case to the extent (if at all) permitted under the
terms and conditions of such contracts. To the extent that any such agreement is not assignable by CELGENE, then such agreement will not be assigned, and upon the written request of EPIZYME, CELGENE will cooperate in good faith and use Commercially
Reasonable Efforts to allow EPIZYME to obtain and enjoy the benefits of such agreement in the form of a license or other right to the extent held by CELGENE and subject to such Third Party’s rights, in each case to the extent (if at all)
permitted under the terms and conditions of such contracts. EPIZYME shall be solely responsible for any and all costs, expenses and liabilities of any kind arising in connection with any such contract assignment or extension of license or other
rights to EPIZYME under this Section 12.6.1(j) or EPIZYME’s holding or use of such assigned contracts or rights licensed or otherwise provided to EPIZYME under this Section 12.6.1(j). 

(k) Manufacturing. Upon EPIZYME’s written request, CELGENE shall, as part of the transition plan to be mutually agreed by the
Parties under Section 12.6.1(c), 

  
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transfer to EPIZYME (or its designee) a copy of any processes, documents, materials and other Know-How, to the extent the foregoing is Controlled by CELGENE as of the effective date of
termination and used in the Manufacture of Terminated Products in the Field in the Terminated Country(ies) as of the effective date of termination; provided however that, CELGENE will, upon EPIZYME’s written request and
pursuant to a supply agreement to be negotiated in good faith by the Parties for the Terminated Country(ies) at the transfer price paid by CELGENE for the applicable Terminated Product plus [**] percent ([**]%) if CELGENE sources such Terminated
Product from a Third Party, or at CELGENE’s direct manufacturing cost plus [**] percent ([**]%) if CELGENE or any of its Affiliates Manufactures the applicable Terminated Product, continue to supply EPIZYME with clinical and commercial
quantities of such Terminated Product in the dosage strength, formulation and presentation under Development or being Commercialized by CELGENE, in either case, as of the effective date of termination, until the earlier of: (a) [**] months
after the effective date of termination; or (b) establishment by EPIZYME of an alternative supply for such Terminated Product. 
 (l)
Existing Inventory. In the event this Agreement is terminated in its entirety, at EPIZYME’s election, CELGENE will transfer to EPIZYME such portion of CELGENE’s existing inventory of Terminated Products (including clinical trial
materials and synthetic intermediates, if applicable), as applicable, for the Terminated Country(ies) that EPIZYME elects and, with respect to any commercial supply, that is in good and saleable condition, in its original, unopened packaging, at the
transfer price paid by CELGENE for such Terminated Product if CELGENE sourced such Terminated Product from a Third Party, plus [**] percent ([**]%) or at CELGENE’s direct manufacturing cost plus [**] percent ([**]%) if CELGENE or any of its
Affiliates Manufactured the Terminated Product. 
 (m) Prosecution and Enforcement. Except for Sections 8.1, 8.5 (to the extent set
forth in this Section 12.6.1(m)) and 8.8, the provisions of Article 8 shall be terminated if the Agreement is terminated in its entirety or, if applicable, solely with respect to the Terminated Target and Terminated Products in the Terminated
Country(ies). In addition, to the extent that any Patents Controlled by CELGENE are exclusively licensed to EPIZYME pursuant to clause (d) above, as between the Parties, EPIZYME shall have the first right (but not the obligation) to Prosecute
and Maintain, enforce and defend pursuant to the principles set forth in Section 8.5 all such exclusively licensed Patents that relate solely to the Terminated Target(s) and Terminated Products in the Terminated Country(ies) and CELGENE shall
provide such assistance and cooperation as may be reasonably necessary in connection therewith. 
 (n) Survival. In the event this
Agreement is terminated in its entirety, Section 12.7.2 shall apply. For clarity, the licenses set forth in Sections 5.2.3(b) and 5.2.5 (each, as set forth in Section 12.6.1(d)) and 5.1.5 shall survive any termination of this Agreement by
CELGENE pursuant to Section 12.2 or by EPIZYME pursuant to Section 12.3 or Section 12.5, whether terminated in its entirety or on a Selected Target-by-Selected Target basis. 

Notwithstanding the foregoing provisions of this Section 12.6.1, if CELGENE terminates this Agreement in its entirety or with respect to one or more but
not all Selected Targets in accordance with Section 12.2 as a result of material safety concerns that CELGENE in good faith determines make the further Development or Commercialization of Licensed Compound(s) and


  
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Licensed Product(s) Directed to such Selected Target(s) unreasonable from a scientific, regulatory or ethical perspective (without regard to commercial potential), then CELGENE’s licenses
under Section 5.1.5 shall terminate with respect to such Terminated Targets and the foregoing Sections 12.6.1(c), 12.6.1(d), 12.6.1(e), 12.6.1(f), 12.6.1(h), 12.6.1(i), 12.6.1(j), 12.6.1(k) and 12.6.1(l) shall not apply to such Licensed
Compound(s) and Licensed Product(s) Directed to such Selected Target(s); provided that, CELGENE, for itself and its Affiliates, hereby covenants and agrees not to assert any Patent rights Controlled by CELGENE or its Affiliates against
EPIZYME or its Affiliates, or any of their successors, assigns, (sub)licensees, distributors, manufacturers or customer with respect to the Manufacture, use, offer for sale, sale or importation of such Licensed Compound and Licensed Product. 

12.6.2 Termination by CELGENE pursuant to Section 12.3 or 12.5. In the event of termination of this Agreement with respect to all
or one or more Selected Targets by CELGENE pursuant to Section 12.3 or 12.5, the following shall apply: 
 (a) License
Survival. The licenses granted to CELGENE pursuant to Sections 5.1.3 and 5.1.4, and the licenses granted to EPIZYME pursuant to Sections 5.2.2 through 5.2.4 inclusive (but excluding Section 5.2.3(b)), shall, with respect to such Selected
Target(s) and Licensed Compounds and Licensed Products Directed to such Selected Target(s), (i) become irrevocable and non-terminable (except as provided in Section 12.6.3 if, as applicable, CELGENE engages in a CELGENE Patent Challenge or
EPIZYME engages in an EPIZYME Patent Challenge); (ii) solely be under the applicable EPIZYME IP and EPIZYME’s interest in the Joint Collaboration IP (if applicable) or the applicable CELGENE IP and CELGENE’s interest in the Joint
Collaboration IP (if applicable), respectively, in each case existing as of, and to the extent licensed and used at, the time of termination, and (iii) survive any such termination. For purposes of clarity, any Selected Target that is the
subject of such termination shall not be deemed a Terminated Target by virtue of CELGENE exercising its termination right under Section 12.3 or 12.5. 

(b) Committees. CELGENE shall have sole responsibility and decision-making authority in the CELGENE Territory over all research,
Development, Manufacture and Commercialization of Licensed Compounds and Licensed Products Directed to the Selected Target(s) to which such termination applies. EPIZYME shall have sole responsibility and decision-making authority in the EPIZYME
Territory over all research, Development, Manufacture and Commercialization of Licensed Compounds and Licensed Products Directed to the Selected Target(s) to which such termination applies. The applicable Selected Target and related Development
Program, if applicable, shall no longer be within the purview of the JRC, JDC or JCC. In the event this Agreement is terminated in its entirety, the JRC, JDC, JCC and Patent Committee shall be disbanded. 

(c) All Other Provisions. Subject to Sections 12.6.2(a) and (b), all other provisions of this Agreement shall survive any such
termination with respect to such Selected Target except for: Sections 5.1 and 5.2 (except for Sections 5.1.5, 5.1.6, 5.2.3(b), 5.2.5 and 5.2.6 and except as provided in Section 12.6.2(a)) and 5.3 (provided that for purposes of
clarity, any Compound that is a CELGENE Lead Candidate pursuant to Section 5.3 prior to the effective date of termination shall continue to be a CELGENE Lead Candidate for purposes of 

  
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Section 1.77(z)); 6.2, 6.3 and 6.4 (each, with respect to costs accrued after the effective date of termination); 7.1 (if (i) CELGENE terminates on a Selected Target-by-Selected Target
basis after expiration of the Option Term, with respect to such Selected Target or (ii) this Agreement is terminated in its entirety); and Articles 1 (to the extent definitions are not required to interpret the surviving provisions of this
Agreement); 2 (except for Sections 2.3.2(a)(iii)(z), 2.3.3, 2.11, 2.12.4, 2.12.5(d)(2) – (5), inclusive, 2.12.5(e), and 2.12.5(f)); 3 (except for Sections 3.4.3(c) and 3.6); 4; 8 (except for Sections 8.1, 8.5 (to the extent set forth in this
Section 12.6.2(c)) and 8.8, provided that to the extent that any Patents Controlled by one Party are exclusively licensed to the other Party pursuant to Section 12.6.2(a) above, as between the Parties, the licensed Party
shall have the first right (but not the obligation) to Prosecute and Maintain, enforce and defend pursuant to the principles set forth in Section 8.5 all such exclusively licensed Patents that relate solely to such Selected Target and the
licensing Party shall provide such assistance and cooperation as may be reasonably necessary in connection therewith); 10 (except for Sections 10.4 and 10.5); and 12 (except for Sections 12.2, 12.4, 12.6.1, 12.6.2, 12.6.3, 12.7.1 and 12.7.3). In the
event this Agreement is terminated in its entirety, Section 12.7.2 shall apply. 
 12.6.3 Termination by EPIZYME or CELGENE pursuant
to Section 12.4. In the event of termination by EPIZYME or CELGENE pursuant to Section 12.4, (w) termination of a Selected Target shall be effective with respect to the entire Development Program for such Selected Target;
(x) the applicable Selected Target shall be deemed a “Terminated Target” and all Licensed Compounds and Licensed Products Directed to such Terminated Target, and related Diagnostic Products, shall be deemed “Terminated
Products,” (y) all countries in the CELGENE Territory shall be deemed “Terminated Countries” with respect to the applicable Terminated Target or Lapsed Target and the EPIZYME Territory shall include such Terminated Countries
with respect to such Terminated Target or Lapsed Target and (z) the following shall apply: 
 (a) Termination by EPIZYME. On a
Terminated Target-by-Terminated Target or Lapsed Target-by-Lapsed Target basis, as applicable, in the event EPIZYME terminates this Agreement pursuant to Section 12.4.1, (i) the provisions of Section 12.6.1 shall apply solely with
respect to such Terminated Target, and (ii) all licenses granted to CELGENE under Section 5.1.5 with respect to such Terminated Target and Terminated Products or Lapsed Target, as applicable, shall be terminated and of no further force and
effect. 
 (b) Termination by CELGENE. On a Terminated Target-by-Terminated Target or Lapsed Target-by-Lapsed Target basis, as
applicable, in the event CELGENE terminates this Agreement pursuant to Section 12.4.2, (i) all licenses granted to EPIZYME under Sections 5.2.1 through 5.2.5, inclusive, with respect to the Terminated Target and Terminated Products or
Lapsed Target, as applicable, shall be terminated and of no further force and effect; (ii) the licenses granted to CELGENE pursuant to Sections 5.1.3 and 5.1.4 shall become perpetual, irrevocable and fully paid-up with respect to such
Terminated Target and Terminated Products and shall survive any such termination, and (iii) all provisions of this Agreement shall terminate except as set forth in Section 12.6.3(b)(ii) and Section 12.7.2 (subject to
Section 12.6.3(b)(i)) and shall apply solely with respect to such Terminated Target. 

  
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 12.7 Accrued Rights; Surviving Provisions; Right to Set-off. 

12.7.1 Accrued Rights. Termination, relinquishment or expiration of this Agreement for any reason shall be without prejudice to any
rights that shall have accrued to the benefit of any Party prior to such termination, relinquishment or expiration, including the payment obligations under Article 6 hereof, and any and all damages or remedies (whether in law or in equity) arising
from any breach hereunder. Such termination, relinquishment or expiration shall not relieve any Party from obligations which are expressly indicated to survive termination of this Agreement. 

12.7.2 Surviving Provisions. The provisions of Sections 2.3.2(a)(iii)(z), 2.3.3, 2.4.2(b)(ii)(4), 2.11, 2.12.5(d)(2) – (5),
inclusive, 2.12.5(e), and 2.12.5(f); 5.1.5, 5.1.6, 5.2.3(b), 5.2.5 and 5.2.6 (in the case of each of the foregoing sections, except as otherwise provided in Section 12.6); 5.4; 5.5; 10.5; 12.1.2; 12.6 and 12.7; and Articles 1 (to the extent
definitions are required to interpret the surviving provisions of this Agreement); 6 (to the extent due but unpaid as of the effective date of termination and to the extent the provisions of Article 6 relate to payment obligations that otherwise
survive pursuant to Section 12.6); 8 (with respect to the provisions related to ongoing activities related to Joint Collaboration Patents, and 8.1 and 8.8); 9; 11 and 13 shall survive the termination of this Agreement in its entirety or
expiration of this Agreement for any reason, in accordance with their respective terms and conditions, and for the duration stated, and where no duration is stated, shall survive indefinitely. Article 9 shall survive for a period of [**] years after
the effective date of termination of this Agreement. 
 12.7.3 Right to Set-off. Notwithstanding anything to the contrary in this
Agreement, each Party has the right at all times to retain and set off against all amounts due and owing to the other Party as determined in a final judgment any damages recovered by such Party for any Losses incurred by such Party; it being
understood and agreed that during the pendency of any failure of EPIZYME to pay its share of Development Costs, CELGENE shall have the right to deduct from any milestones, royalties or other payments to be made to EPIZYME under this Agreement and
deposit such amounts into escrow (pursuant to a separate escrow agreement with an escrow agent on terms customary for agreements of this type) for an amount of any and all such Development Cost payment failures in the aggregate exceeding [**]
Dollars ($[**]). 
 ARTICLE 13 

MISCELLANEOUS 
 13.1
Dispute Resolution. Except for disputes within the responsibilities of the JRC or JDC, JCC or the Patent Committee, with respect to which a Party has final decision-making authority pursuant to Section 4.4.2, 4.3.4, or 4.5.5,
respectively, if a dispute between the Parties arises under this Agreement, either Party shall have the right to refer such dispute in writing to the respective Executive Officers, and such Executive Officers shall attempt in good faith to resolve
such dispute. If the Parties are unable to resolve a given dispute pursuant to this Section 13.1 within [**] days after referring such dispute to the Executive Officers, then if either Party seeks to have the dispute formally resolved, it shall
do so in the following manner: (a) following an EPIZYME Business Combination or License Event and in accordance with Section 4.4.2(c), either Party may submit any dispute within the purview of the JDC (each an “Arbitration
Dispute”) to arbitration pursuant to Section 13.2; and (b) all other disputes shall be resolved by litigation pursuant to Section 13.3. 

  
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 13.2 Baseball Arbitration. If a Party intends to begin an arbitration to resolve an
Arbitration Dispute, such Party shall provide written notice (the “Arbitration Request”) to the other Party of such intention and a statement of the Arbitration Dispute for resolution. From the date of the Arbitration Request and
until such time as the Arbitration Dispute has become finally settled, the running of the time periods as to which the other Party must cure a breach of this Agreement becomes suspended as to any breach that is the subject matter of the Arbitration
Dispute. 
 13.2.1 Arbitration Procedure. Any arbitration pursuant to this Section 13.2 will be held in New York, New York,
United States unless another location is mutually agreed by the Parties. The arbitration will be governed by the United States Arbitration Act, 9 U.S.C. §§ 1-16, to the exclusion of any inconsistent state Law. The arbitration will be
conducted by a single arbitrator knowledgeable in the subject matter at issue in the Arbitration Dispute and acceptable to both Parties; provided however that, the Parties may by mutual agreement elect to have the arbitration
conducted by a panel of three (3) arbitrators (such single arbitrator or panel, the “Arbitrator”). If the Parties fail to agree on a mutually acceptable Arbitrator within [**] days after the Arbitration Request, then the
Arbitrator shall be selected by the New York, New York office of the AAA. The Arbitrator may proceed to an award, notwithstanding the failure of either Party to participate in the proceedings. The Arbitrator shall be limited in the scope of his or
her authority to resolving only the Arbitration Dispute and shall not have authority to render any decision or award on any other issues. Subject to Section 11.5 and 13.2.2, the Arbitrator shall be authorized to (a) award compensatory
damages, but shall not be authorized to award punitive, special, consequential, or any other similar form of damages, or to reform, modify or materially change this Agreement, and (b) grant any temporary, preliminary or permanent equitable
remedy or relief the arbitrator deems just and equitable and within the scope of this Agreement, including an injunction or order for specific performance. The award of the Arbitrator shall be the sole and exclusive remedy of the Parties, and the
Parties hereby expressly agree to waive the right to appeal from the decisions of the Arbitrator, and there shall be no appeal to any court or other authority (government or private) from the decision of the Arbitrator. Judgment on the award
rendered by the Arbitrator may be enforced in any court having competent jurisdiction thereof, subject only to revocation of the award on grounds set forth in the United Nations Convention on the Recognition and Enforcement of Foreign Arbitral
Awards. 
 13.2.2 Submission of Summaries. Each Party will prepare and submit a written summary of such Party’s position and any
relevant evidence in support thereof to the Arbitrator within [**] days of selection of the Arbitrator. Upon receipt of such summaries from both Parties, the Arbitrator will provide copies of the same to the other Party. The Arbitrator will be
authorized to solicit briefing or other submissions on particular questions. Within [**] days of the delivery of such summaries by the Arbitrator, each Party will submit a written rebuttal of the other Party’s summary and may also amend and
re-submit its original summary. Oral presentations will not be permitted unless otherwise requested by the Arbitrator. The Arbitrator will make a final decision with respect to the Arbitration Dispute within [**] days following receipt of the last
of such rebuttal statements submitted by the Parties and will make a determination by selecting the resolution proposed by one of the Parties that as a whole is the most fair and reasonable to the Parties in light of the totality of the
circumstances and that 

  
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complies with the terms of this Agreement and will provide the Parties with a written statement setting forth the basis of the determination in connection therewith. For purposes of clarity, the
Arbitrator will only have the right to select a resolution proposed by one of the Parties in its entirety and without modification provided such resolution complies with the terms of this Agreement. 

13.2.3 Costs. Each Party shall bear its own attorneys’ fees, costs, and disbursements arising out of the arbitration, and shall
pay an equal share of the fees and costs of the Arbitrator; provided however that the Arbitrator, in his or her award, shall be authorized to determine whether a Party is the prevailing Party, and if so, to award to that
prevailing Party reimbursement for its reasonable attorneys’ fees, costs and disbursements (including, for example, expert witness fees and expenses, transcripts, photocopy charges and travel expenses). 

13.2.4 Preliminary Injunctions. Notwithstanding anything in this Agreement to the contrary, a Party may seek a temporary restraining
order or a preliminary injunction from any court of competent jurisdiction in order to prevent immediate and irreparable injury, loss, or damage on a provisional basis, pending the award of the Arbitrator on the ultimate merits of any Arbitration
Dispute. 
 13.2.5 Confidentiality. All proceedings and decisions of the Arbitrator shall be deemed Confidential Information of each
of the Parties, and shall be subject to Article 9. 
 13.3 Venue; Jurisdiction. Each Party hereby irrevocably and unconditionally
consents to submit to the exclusive jurisdiction of the federal courts located in the Southern District of New York, for any actions, suits or proceedings arising out of or relating to this Agreement and the transactions contemplated hereby. Each
Party hereby irrevocably and unconditionally waives any objection to the laying of venue of any action, suit or proceeding arising out of or relating to this Agreement and the transactions contemplated hereby in the federal courts located in the
Southern District of New York, and waives and agrees not to plead or claim in any such court that any such action, suit or proceeding brought in such court has been brought in an inconvenient forum. Notwithstanding the foregoing, a Party shall be
entitled to seek enforcement of either an arbitration award issued pursuant to Section 13.2 or a judgment entered pursuant to this Section in any court having competent jurisdiction thereof where enforcement is deemed necessary. 

13.4 Governing Law. This Agreement and any dispute arising from the performance or breach hereof shall be governed by and construed and
enforced in accordance with the Laws of the State of New York without reference to conflicts of laws principles; provided however that with respect to matters involving the enforcement of intellectual property rights, the Laws
of the applicable country shall apply. The provisions of the United Nations Convention on Contracts for the International Sale of Goods shall not apply to this Agreement or any subject matter hereof. 

13.5 Assignment. Neither Party may assign this Agreement without the consent of the other Party, except as otherwise provided in this
Section 13.5. Either Party may assign this Agreement in whole or in part to any Affiliate of such Party without the consent of the other 

  
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Party; provided however that, such assigning Party provides the other Party with written notice of such assignment and the assignee agrees in writing to assume performance of
all assigned obligations. Further, subject to the remainder of this Section 13.5, each Party may assign this Agreement, and all of its rights and obligations hereunder, to which this Agreement relates, without the consent of the other Party to
its successor in interest by way of merger, acquisition, or sale of all or substantially all of its business or assets to which this Agreement relates (an “M&A Event”); provided however that, such assigning
Party provides the other Party with written notice of such assignment and the assignee agrees in writing to assume performance of all assigned obligations. Each Party agrees that, notwithstanding any provisions of this Agreement to the contrary, no
Patent, Know-How or other intellectual property or other proprietary rights not Controlled by a Party or any of its Affiliates prior to a M&A Event or Business Acquisition with respect to a Party will be Controlled for purposes of this Agreement
after such M&A Event or Business Acquisition, other than (a) Collaboration IP and Joint Collaboration IP created, conceived or reduced to practice in connection with the activities performed pursuant to this Agreement, no matter when
Controlled and (b) any Patent that claims priority, directly or indirectly, to any other Patent first Controlled before the M&A Event or Business Acquisition will be Controlled thereafter no matter when such Patent is filed or issued. The
assigning Party shall remain primarily liable for the performance of its obligations under this Agreement by its assignees. The terms of this Agreement shall be binding upon and shall inure to the benefit of the successors, heirs, administrators and
permitted assigns of the Parties. Any purported assignment in violation of this Section 13.5 shall be null and void ab initio. 
 13.6
Performance Warranty. Each Party hereby acknowledges and agrees that it shall be responsible for the full and timely performance as and when due under, and observance of all the covenants, terms, conditions and agreements set forth in this,
Agreement by its Affiliate(s) and Sublicensees. 
 13.7 Force Majeure. No Party shall be held liable or responsible to the other
Party nor be deemed to be in default under, or in breach of any provision of, this Agreement for failure or delay in fulfilling or performing any obligation of this Agreement when such failure or delay is due to force majeure, and without the fault
or negligence of the Party so failing or delaying. For purposes of this Agreement, force majeure is defined as causes beyond the control of the Party, including acts of God; material changes in Law; war; civil commotion; destruction of production
facilities or materials by fire, flood, earthquake, explosion or storm; labor disturbances; epidemic; and failure of public utilities or common carriers. In such event EPIZYME or CELGENE, as the case may be, shall immediately notify the other Party
of such inability and of the period for which such inability is expected to continue. The Party giving such notice shall thereupon be excused from such of its obligations under this Agreement as it is thereby disabled from performing for so long as
it is so disabled for up to a maximum of ninety (90) days, after which time EPIZYME and CELGENE shall promptly meet to discuss in good faith how to best proceed in a manner that maintains and abides by the Agreement. To the extent possible,
each Party shall use reasonable efforts to minimize the duration of any force majeure. 
 13.8 Notices. Any notice or request
required or permitted to be given under or in connection with this Agreement shall be deemed to have been sufficiently given if in writing and 

  
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personally delivered or sent by certified mail (return receipt requested), facsimile transmission (receipt verified), or overnight express courier service (signature required), prepaid, to the
Party for which such notice is intended, at the address set forth for such Party below: 
 If to EPIZYME, 

 

					
	addressed to:	 	Epizyme, Inc.
		 	400 Technology Square, 4th Floor
		 	Cambridge, Massachusetts 02139
		 	Attention: Chief Financial Officer
		 	Telephone:	 	(617) 500-0712
		 	Facsimile:	 	      (617) 349-0707
		
	with a copy to:	 	WilmerHale LLP
		 	60 State Street
		 	Boston, MA 02109
		 	Attention:	 	Stuart M. Falber, Esq.
		 		 	Steven D. Barrett, Esq.
		 	Telephone:	 	      (617) 526-6000
		 	Facsimile:	 	      (617) 526-5000

 If to CELGENE, 
  

					
	addressed to:	 		 	
		
		 	Celgene RIVOT Ltd.
		 	Clarendon House, 2 Church Street
		 	Hamilton, HM 11
		 	Bermuda
		 	Attention:	 	      Chief Operations Officer
		 	Telephone:	 	      (441) 296 4803
		 	Facsimile:	 	      (441) 298 7809
		
	with a copy to:	 	Celgene Legal
		 	86 Morris Avenue
		 	Summit, NJ 07901
		 	Attention: General Counsel
		 	Telephone: (908) 673-9000
		 	Facsimile: (908) 673-2771


  
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	with a copy to	 	Dechert LLP
		 	1900 K Street, NW
		 	Washington, DC 20006
			
		 	Attention:	 	David E. Schulman
		 		 	Thomas A. Rayski
		 	Telephone:	 	+1 202 261 3440
		 	Facsimile:	 	+1 202 261 3333

 or to such other address for such Party as it shall have specified by like notice to the other Party; provided
however that notices of a change of address shall be effective only upon receipt thereof. If delivered personally or by facsimile transmission, the date of delivery shall be deemed to be the date on which such notice or request was
given. If sent by overnight express courier service, the date of delivery shall be deemed to be the next Business Day after such notice or request was deposited with such service. If sent by certified mail, the date of delivery shall be deemed to be
the third (3rd) Business Day after such notice or request was deposited with the U.S. Postal Service. 
 13.9 Export Clause.
Each Party acknowledges that the Laws of the United States restrict the export and re-export of commodities and technical data of United States origin. Each Party agrees that it will not export or re-export restricted commodities or the technical
data of the other Party in any form without the appropriate United States and foreign government licenses. 
 13.10 Waiver. Neither
Party may waive or release any of its rights or interests in this Agreement except in writing. The failure of either Party to assert a right hereunder or to insist upon compliance with any term of this Agreement shall not constitute a waiver of that
right or excuse a similar subsequent failure to perform any such term or condition. No waiver by either Party of any condition or term in any one or more instances shall be construed as a continuing waiver of such condition or term or of another
condition or term. 
 13.11 Severability. If any provision hereof should be held invalid, illegal or unenforceable in any
jurisdiction, the Parties shall negotiate in good faith a valid, legal and enforceable substitute provision that most nearly reflects the original intent of the Parties and all other provisions hereof shall remain in full force and effect in such
jurisdiction and shall be liberally construed in order to carry out the intentions of the Parties hereto as nearly as may be possible. Such invalidity, illegality or unenforceability shall not affect the validity, legality or enforceability of such
provision in any other jurisdiction. 
 13.12 Entire Agreement. This Agreement, together with the Exhibits and Schedules hereto and
the Research Plan and any Development Plans, and the Stock Purchase Agreement set forth all the covenants, promises, agreements, warranties, representations, conditions and understandings between the Parties and supersede and terminate all prior
agreements and understanding between the Parties with respect to the subject matter of this Agreement. In 

  
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particular, and without limitation, this Agreement supersedes and replaces the Existing Confidentiality Agreement and any and all term sheets relating to the transactions contemplated by this
Agreement and exchanged between the Parties prior to the Effective Date. There are no covenants, promises, agreements, warranties, representations, conditions or understandings, either oral or written, between the Parties with respect to the subject
matter of this Agreement other than as set forth herein and therein. No subsequent alteration, amendment, change or addition to this Agreement shall be binding upon the Parties unless reduced to writing and signed by the respective authorized
officers of the Parties. 
 13.13 Independent Contractors. Nothing herein shall be construed to create any relationship of employer
and employee, agent and principal, partnership or joint venture between the Parties. Each Party is an independent contractor. Neither Party shall assume, either directly or indirectly, any liability of or for the other Party. Neither Party shall
have the authority to bind or obligate the other Party and neither Party shall represent that it has such authority. 
 13.14
Non-solicitation of Key Employees. During the Option Term, neither Party nor its Affiliates shall solicit any Key Employee to leave the employment of the other Party and accept employment or work as a consultant with the soliciting Party.
Notwithstanding the foregoing, nothing herein shall restrict or preclude either Party’s or its Affiliates’ right to make generalized searches for employees by way of a general solicitation for employment placed in a trade journal,
newspaper or website. For purposes of this Section 13.14, “Key Employee” means any employee who is material to the performance of the Collaboration hereunder, including any members of the JRC, JDC or any Subcommittee thereof,
including the employees set forth on Schedule 13.14. 
 13.15 Headings; Construction; Interpretation. Headings used herein are
for convenience only and shall not in any way affect the construction of or be taken into consideration in interpreting this Agreement. The terms of this Agreement represent the results of negotiations between the Parties and their representatives,
each of which has been represented by counsel of its own choosing, and neither of which has acted under duress or compulsion, whether legal, economic or otherwise. Accordingly, the terms of this Agreement shall be interpreted and construed in
accordance with their usual and customary meanings, and each of the Parties hereto hereby waives the application in connection with the interpretation and construction of this Agreement of any rule of Law to the effect that ambiguous or conflicting
terms or provisions contained in this Agreement shall be interpreted or construed against the Party whose attorney prepared the executed draft or any earlier draft of this Agreement. Any reference in this Agreement to an Article, Section,
subsection, paragraph, clause, Schedule or Exhibit shall be deemed to be a reference to any Article, Section, subsection, paragraph, clause, Schedule or Exhibit, of or to, as the case may be, this Agreement. Except where the context otherwise
requires, (a) any definition of or reference to any agreement, instrument or other document refers to such agreement, instrument other document as from time to time amended, supplemented or otherwise modified (subject to any restrictions on
such amendments, supplements or modifications set forth herein or therein), (b) any reference to any Law refers to such Law as from time to time enacted, repealed or amended, (c) the words “herein,” “hereof” and
“hereunder,” and words of similar import, refer to this Agreement in its entirety and not to any 

  
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particular provision hereof, (d) the words “include,” “includes,” and “including,” shall be deemed to be followed by the phrase “but not limited to,”
“without limitation” or words of similar import, and (e) the word “or” is used in the inclusive sense (and/or). 

13.16 Books and Records. Any books and records to be maintained under this Agreement by a Party or its Affiliates or Sublicensees shall
be maintained in accordance with the Accounting Principles, consistently applied, except that the same need not be audited. 
 13.17
Further Actions. Each of EPIZYME, CELGENE and PARENT shall execute, acknowledge and deliver such further instruments, and do all such other acts, as may be necessary or appropriate in order to carry out the expressly stated purposes and the
clear intent of this Agreement. 
 13.18 Parties in Interest. All of the terms and provisions of this Agreement shall be binding
upon, and shall inure to the benefit of and be enforceable by EPIZYME, CELGENE and, as set forth in Section 13.21, PARENT, and each of their respective successors, heirs, administrators and permitted assigns. 

13.19 Performance by Affiliates. To the extent that this Agreement imposes obligations on Affiliates of a Party, such Party agrees to
cause its Affiliates to perform such obligations. 
 13.20 Counterparts. This Agreement may be signed in counterparts, each and every
one of which shall be deemed an original, notwithstanding variations in format or file designation which may result from the electronic transmission, storage and printing of copies from separate computers or printers. Facsimile signatures and
signatures transmitted via PDF shall be treated as original signatures. 
 13.21 PARENT Guarantee. PARENT hereby unconditionally and
irrevocably guarantees, jointly and severally, as a primary obligor and not merely as a surety, the due and timely payment and performance of all obligations of CELGENE under this Agreement (the “Celgene Obligations”). PARENT agrees
that (a) the Celgene Obligations and this Agreement may be extended, modified or renewed, in whole or in part, without notice or further assent from PARENT, and that PARENT will remain bound upon its guarantee notwithstanding any extension,
modification or renewal of any Celgene Obligation or of this Agreement, any assumption of any such guaranteed Celgene Obligation by any other party or any other act or event that might otherwise operate as a legal or equitable discharge of PARENT
under this Section 13.21 (other than any defenses available to CELGENE under this Agreement), and (b) PARENT shall be bound by all of the terms and conditions of Article 9 and this Article 13 (and all of the definitions and capitalized
terms contained therein) as if such Section applied to PARENT. PARENT further agrees that its guarantee constitutes an irrevocable guarantee of payment and performance when due (and not just of collection) and waives any right to require that any
resort be had by EPIZYME to any other guarantee for any security held for payment or performance of the Celgene Obligations. This guarantee is in no way conditioned upon any requirement that EPIZYME first attempt to collect or enforce any guaranteed
obligation from or against CELGENE. 

  
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 Except with respect to any defenses available to CELGENE under this Agreement: (y) the obligations of PARENT
hereunder shall be absolute and unconditional irrespective of the validity, legality or enforceability of this Agreement or any other document related hereto, and shall not be affected by or contingent upon any modification, alteration, amendment or
addition of or to this Agreement; and (z) PARENT hereby waives all special suretyship defenses and protest, notice of protest, demand for performance, diligence, notice of any other action at any time taken or omitted by EPIZYME and, generally,
all demands and notices of every kind in connection with this Section 13.21 and the Celgene Obligations hereby guaranteed, and which PARENT may otherwise assert against EPIZYME. PARENT acknowledges that each of the waivers set forth above is
made with full knowledge of its significance and consequences and under the circumstances the waivers are reasonable and not contrary to public policy. If any of said waivers is determined to be contrary to any applicable Law or public policy, such
waivers shall be effective only to the extent permitted by Law. 
 [Signature page to follow] 

  
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 EXECUTION VERSION 

IN WITNESS WHEREOF, and intending to be legally bound hereby, the Parties have caused this Agreement to be executed by their duly authorized
representatives as of the Effective Date. 
  

					
	Epizyme, Inc.
		
	By:	 	 /s/ Robert Gould

		 	Name:	 	Robert Gould
		 	Title:	 	President and CEO
	
	Celgene RIVOT Ltd.
		
	By:	 	 /s/ Kevin Mello

		 	Name:	 	Kevin Mello
		 	Title:	 	Director, Celgene RIVOT Ltd.
	
	Celgene Corporation (solely for the purposes set forth in Section 13.21)
		
	By:	 	 /s/ Tom Daniel

		 	Name:	 	Tom Daniel
		 	Title:	 	EVP/President, Research & Early Development


 [Signature page to Collaboration and License Agreement] 







 EXECUTION VERSION 

EXHIBIT A 

Initial Research Plan 
 Project
Background 
 Confidential Materials omitted and filed separately with the Securities and Exchange Commission. A total of four pages were omitted.
[**] 

  
 A-1 









 EXECUTION VERSION 
  

 Epizyme, Inc. 

General Discovery Activities by Stage 

Target Validation: [**]. 
 Target-to-Hit:
[**]. 
 Hit-to-Lead: [**]. 

Lead-to-Candidate: [**]. 

Candidate-to-IND: [**]. 

  
 A-2 








 EXECUTION VERSION 

EXHIBIT B 
 Form
of CELGENE Provided Compound Transfer Agreement 
 This CELGENE Provided Compound Transfer Agreement No.     (the “Transfer
Agreement”) is made as of
                                         (the
“Transfer Agreement Effective Date”), by and between Epizyme, Inc. and Celgene RIVOT Ltd., pursuant to that certain Collaboration and License Agreement, entered into among Epizyme, Inc., Celgene RIVOT Ltd. and Celgene Corporation,
with an Effective Date of             , 2015 (the “Agreement”), for the transfer of: 

CELGENE Provided Compound: 
 [List identity and
chemical structure of CELGENE Provided Compound.] 
 The Parties acknowledge and agree that the CELGENE Provided Compound is Confidential Information of
CELGENE and that the transfer of the CELGENE Provided Compound pursuant to this Transfer Agreement will be pursuant to and in accordance with the terms and conditions of the Agreement. Any capitalized terms used in this Transfer Agreement that are
not defined herein have the meanings ascribed to them in the Agreement. 
 IN WITNESS WHEREOF, this Transfer Agreement is entered into as of the Transfer
Agreement Effective Date, and it is accepted and agreed to by the Parties’ authorized representatives. 
  

									
	For CELGENE RIVOT LTD.:	 		 	For EPIZYME, INC.
					
	By:	 	  
	 		 	By:	 	  

					
	Name:	 	  
	 		 	Name:	 	  

					
	Title	 	Alliance Manager	 		 	Title:	 	Chief Scientific Officer


  
 B-1 








 EXECUTION VERSION 

EXHIBIT C 
 Press
Release 
  
 



 
 Epizyme Announces Extension of Celgene Research Collaboration 

 

	 	•	 	Collaboration to focus on three first-in-class preclinical epigenetic targets 

  

	 	•	 	Epizyme to receive $10 million extension fee payment and up to $610 million in potential milestones 

  

	 	•	 	Epizyme extends cash runway through at least the end of the second quarter of 2017 


Cambridge, Mass., July 9, 2015 – Epizyme, Inc. (NASDAQ: EPZM), a clinical stage biopharmaceutical company creating novel epigenetic therapies
for cancer patients, today announced that it has amended and restated its agreement with Celgene Corporation to extend the research collaboration between the two companies for at least three additional years. Under the collaboration, Celgene will
have the option to license histone methyltransferase (HMT) inhibitors being developed by Epizyme against three predefined targets. 
 Under the terms of the
revised agreement: 
  

	 	•	 	Epizyme will receive a $10 million extension fee from Celgene in return for an option to individually license global rights for two of the targets and ex-US rights for the third target. 


 

	 	•	 	Celgene may exercise its option with respect to each of the targets at the time of the IND filing for an additional pre-specified license payment. 


 

	 	•	 	Epizyme will be responsible for leading and funding development for each target candidate through phase 1 clinical trials. 

  

	 	•	 	Following the completion of phase 1, if Celgene chooses to continue its license for a specific target, it may do so by making an additional pre-specified payment. 


 

	 	•	 	Epizyme may earn total potential milestones of up to $610 million on the three targets, including up to $75 million in development milestones and license fees, $365 million in regulatory milestones, and $170 million in
sales milestones. 

  

	 	•	 	Epizyme also may earn a royalty of up to a low double digit percentage on worldwide net sales for two of the product candidates, and on ex-US net sales for the third product candidate. 


 

	 	•	 	Epizyme will retain global rights to the remainder of its pipeline as Celgene’s option to license ex-US rights for any other preclinical programs will terminate. 


In addition, Celgene will retain its ex-US license to, and the companies will continue their ongoing clinical collaboration on, pinometostat (EPZ-5676), an
HMT inhibitor targeting DOT1L. Pinometostat is in phase 1 development for the treatment of patients with acute leukemia with alterations in the MLL gene (MLL-r). 

  
 C-1 








 “We believe that the extension of our agreement with Celgene will accelerate our goal of developing new
therapies that have the potential to help many patients with epigenetically driven cancers,” said Robert Gould, Ph.D., President and Chief Executive Officer, Epizyme. “Celgene is a leading company in oncology development and
commercialization and we are pleased to continue our partnership on pinometostat and these three exciting novel targets.” 
 The term of this agreement
is based on specific development milestones, including the timing of IND filings and completion of phase 1 studies, but will extend for a minimum of three years. In addition, Celgene will no longer have the right of first negotiation on a business
combination with Epizyme. 
 Financial Update 
 The
Company also announced today that, based on its current operating plans, it projects that its cash and cash equivalents will be sufficient to fund operations through at least the end of the second quarter of 2017, prior to including any potential
option exercise fees or future milestone payments. This new cash outlook reflects a significant reallocation of resources, implementation of cost savings initiatives, the additional capital provided from the Celgene extension fee payment and
the partial exercise of the overallotment option in April from the Company’s March public financing. 
 “We have increased investment in
tazemetostat development, both as a single agent and in future studies in combination with other agents,” said Andrew Singer, Executive Vice President and Chief Financial Officer at Epizyme. “This required reprioritizing our pipeline
development plans and reducing operating costs. We are excited about the updated data from our dose escalation and dose expansion studies presented at the International Congress on Malignant Lymphoma in Lugano, Switzerland on June 20. We look
forward to presenting additional data at the European Society for Medical Oncology’s European Cancer Congress in Vienna, Austria on September 26.” 

About Tazemetostat (EPZ-6438) 
 Epizyme is developing
tazemetostat for the treatment of non-Hodgkin lymphoma patients and patients with INI1-deficient solid tumors. Tazemetostat is a first-in-class small molecule inhibitor of EZH2 developed by Epizyme. In many human cancers, aberrant EZH2 enzyme
activity results in misregulation of genes that control cell proliferation resulting in the rapid and unconstrained growth of tumor cells. Tazemetostat is the WHO International Non-Proprietary Name (INN) for compound EPZ-6438. 

Tazemetostat is the second HMT inhibitor to enter human clinical development (following Epizyme’s DOT1L inhibitor, pinometostat). 

Epizyme is conducting a five-arm, multi-center international phase 2 clinical trial that will assess the safety and activity of tazemetostat in patients with
relapsed or refractory non-Hodgkin lymphoma. A phase 1 dose escalation and dose expansion trial of tazemetostat is also ongoing, with additional data expected to be reported later in 2015. Additional information about this program, including
clinical trial information, may be found here: https://clinicaltrials.gov/ct2/show/NCT01897571 

  
 C-1 








 About Pinometostat (EPZ-5676) 

Epizyme is developing pinometostat, a small molecule inhibitor of DOT1L created with Epizyme’s proprietary product platform, for the treatment of patients
with acute leukemia in which the MLL gene is rearranged due to a chromosomal translocation (MLL-r). Due to these rearrangements, DOT1L is misregulated, resulting in the increased expression of genes causing leukemia. Pinometostat is the WHO
International Non-Proprietary Name (INN) for compound EPZ-5676. 
 Epizyme believes that pinometostat was the first HMT inhibitor to enter human clinical
development. Epizyme is currently conducting a two-stage Phase 1 study in adult MLL-r patients and in May 2014, initiated a Phase 1b study of pinometostat in pediatric patients with rearrangements of the MLL gene. The adult dose escalation cohorts
have completed enrollment, and an adult MLL-r dose expansion cohort is now enrolling patients. Additional information about these ongoing Phase 1 studies can be found here: http://clinicaltrials.gov/show/NCT01684150 

Pinometostat has been granted orphan drug designation for the treatment of acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML) by the Food and
Drug Administration in the U.S. and by the European Commission in Europe. 
 Epizyme retains all U.S. rights to pinometostat and has granted Celgene an
exclusive license to pinometostat outside of the U.S. 
 Conference Call Information 

Epizyme will host a conference call today at 8:00 a.m. ET to discuss the Celgene agreement and provide a corporate update. To participate in the conference
call, please dial 1-877-844-6886 (domestic) or 1-970-315-0315 (international) and refer to conference ID 64251111. The live webcast can be accessed under “Events and Presentations” in the Investor Relations section of the Company’s
website at www.epizyme.com. 
 The archived webcast will be available on the Company’s website beginning approximately two hours after the event. 

About Epizyme, Inc. 
 Epizyme, Inc. is a clinical stage
biopharmaceutical company creating novel epigenetic therapeutics for cancer patients. Epizyme has built a proprietary product platform that the Company uses to create small molecule inhibitors of a 96-member class of enzymes known as histone
methyltransferases, or HMTs. HMTs are part of the system of gene regulation, referred to as epigenetics, that controls gene expression. Genetic alterations can result in changes to the activity of HMTs, making them oncogenic (cancer-causing). By
focusing on the genetic drivers of cancers, Epizyme’s targeted science seeks to match the right medicines with the right patients. 

  
 C-1 








 For more information, visit www.epizyme.com and connect with us on Twitter at @EpizymeRx. 

Cautionary Note on Forward-Looking Statements 
 Any
statements in this press release about future expectations, plans and prospects for Epizyme, Inc. and other statements containing the words “anticipate,” “believe,” “estimate,” “expect,” “intend,”
“may,” “plan,” “predict,” “project,” “target,” “potential,” “will,” “would,” “could,” “should,” “continue,” and similar expressions,
constitute forward-looking statements within the meaning of The Private Securities Litigation Reform Act of 1995. Actual results may differ materially from those indicated by such forward-looking statements as a result of various important factors,
including: whether the Company’s collaborations will be successful; uncertainties inherent in the initiation of future clinical studies or expansion of ongoing clinical studies and in the availability and timing of data from ongoing clinical
studies; whether interim results from a clinical trial will be predictive of the final results of the trial or the results of future trials; expectations for regulatory approvals to conduct trials or market products; development progress of the
Company’s companion diagnostics; availability of funding sufficient for the Company’s foreseeable and unforeseeable operating expenses and capital expenditure requirements; other matters that could affect the availability or commercial
potential of the Company’s therapeutic candidates or companion diagnostics; and other factors discussed in the “Risk Factors” section of our Form 10-Q filed with the SEC on April 28, 2015, and in our other filings from time to
time with the SEC. In addition, the forward-looking statements included in this press release represent the Company’s views as of the date hereof. The Company anticipates that subsequent events and developments will cause the Company’s
views to change. However, while the Company may elect to update these forward-looking statements at some point in the future, the Company specifically disclaims any obligation to do so. These forward-looking statements should not be relied upon as
representing the Company’s views as of any date subsequent to the date hereof. 
 Media/Investors: 

Andrew Singer 
 Executive Vice President and Chief Financial
Officer 
 Epizyme, Inc. 
 617.500.0712 

asinger@epizyme.com 

  
 C-1 








 EXECUTION VERSION 

EXHIBIT D 

Redacted Version of the Agreement for Disclosure to Investors, Lenders, Acquirors and Merger Partners 

To be attached within [**] days after the Effective Date. 







 EXECUTION VERSION 

EXHIBIT E 

Redacted Version of the Agreement for Disclosure to Potential Licensees, Sublicensees and Collaborators 

To be attached within [**] days after the Effective Date. 







 EXECUTION VERSION 

SCHEDULE 1.35 

Development Candidate Selection Criteria 

Confidential Materials omitted and filed separately with the Securities and Exchange Commission. A total of two pages were omitted. [**] 







 SCHEDULE 1.76 

Lead Candidate Criteria 
 [**] 







 SCHEDULE 1.92 

[**] 







 SCHEDULE 1.115 

[**] 
  

									
	 Official *

Symbol
	 	 Official Full

Name
	 	 KMT Name
	 	 Alternate Names
	 	 Entrez Gene ID

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

 [**] 







 SCHEDULE 1.116 

[**] 
  

									
	 Official *

Symbol
	 	 Official Full

Name
	 	 KMT Name
	 	 Alternate Names
	 	 Entrez Gene ID

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

 [**] 







 SCHEDULE 10.2(a) 

EPIZYME Patents 
  

																							
	 Epizyme

ref #
	 	 Origin
	 	 Target
	 	 Country
	 	 Title
	 	 Appl’n
Status
	 	 Serial Number
	 	 Filing

Date
	 	 Publication
Number
	 	 Publication
Date
	 	 Patent
Number
	 	 Issue

Date

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

 Confidential Materials omitted and filed separately with the Securities and Exchange Commission. A total of nine pages were
omitted. [**] 







 SCHEDULE 10.2(b) 

EPIZYME Agreements 
 Collaboration and
License Agreement, by and between Eisai Co., Ltd. and Epizyme, Inc., dated April 1, 2011. 
 GSK Agreement 

LLS Agreement 
 MMRF Agreement 

UNC Agreement 







 SCHEDULE 13.14 

Key Employees 
 EPIZYME EMPLOYEES: 

[**] 







 CELGENE EMPLOYEES: 

[**]