Document:

EX-10.17

 Exhibit 10.17 
 Execution Version 
 Confidential Materials omitted and filed separately with the
Securities and Exchange Commission. Double asterisks denote omissions. 
 COLLABORATION AND LICENSE AGREEMENT 

by and between 
 EISAI CO., LTD. 
 and 

EPIZYME, INC. 
 CONFIDENTIAL 

 Table of Contents 

 

							
	 	  	 	  	Page	 
		
	ARTICLE 1 DEFINITIONS	  	 	1	  
	 1.1
	  	“Affiliate”	  	 	1	  
	 1.2
	  	“Annual Net Sales”	  	 	2	  
	 1.3
	  	“Bayh-Dole Act”	  	 	2	  
	 1.4
	  	“Budget Year”	  	 	2	  
	 1.5
	  	“Business Day”	  	 	2	  
	 1.6
	  	“Calendar Quarter”	  	 	2	  
	 1.7
	  	“Calendar Year”	  	 	2	  
	 1.8
	  	“cGMP”	  	 	2	  
	 1.9
	  	“Change of Control Event”	  	 	2	  
	 1.10
	  	“Clinical Trial”	  	 	2	  
	 1.11
	  	“Collaboration IP”	  	 	2	  
	 1.12
	  	“Collaboration Know-How”	  	 	2	  
	 1.13
	  	“Collaboration Patents”	  	 	3	  
	 1.14
	  	“Commercialization” and “Commercialize”	  	 	3	  
	 1.15
	  	“Commercialization Costs”	  	 	3	  
	 1.16
	  	“Commercially Reasonable Efforts”	  	 	3	  
	 1.17
	  	“Comparable Third Party Product”	  	 	4	  
	 1.18
	  	“Comparable Third Party Product Competition”	  	 	4	  
	 1.19
	  	“Compound(s)”	  	 	4	  
	 1.20
	  	“Control”, “Controls” or “Controlled”	  	 	4	  
	 1.21
	  	“Cover”, “Covering” or “Covered”	  	 	5	  
	 1.22
	  	“Develop” or “Development”	  	 	5	  
	 1.23
	  	“Development Candidate”	  	 	5	  
	 1.24
	  	“Development Candidate Selection Criteria”	  	 	5	  
	 1.25
	  	“Development Costs”	  	 	5	  
	 1.26
	  	“Diagnostic Know-How”	  	 	5	  
	 1.27
	  	“Diagnostic Patents”	  	 	5	  
	 1.28
	  	“Diagnostic Product”	  	 	5	  
	 1.29
	  	“Dollars” or “$”	  	 	6	  
	 1.30
	  	“EISAI Collaboration IP”	  	 	6	  
	 1.31
	  	“EISAI Collaboration Know-How”	  	 	6	  
	 1.32
	  	“EISAI Collaboration Patents”	  	 	6	  
	 1.33
	  	“EISAI IP”	  	 	6	  
	 1.34
	  	“EISAI Know-How”	  	 	6	  
	 1.35
	  	“EISAI Patent(s)”	  	 	6	  
	 1.36
	  	“EMA”	  	 	6	  
	 1.37
	  	“EPIZYME Collaboration IP”	  	 	6	  
	 1.38
	  	“EPIZYME Collaboration Know-How”	  	 	6	  
	 1.39
	  	“EPIZYME Collaboration Patents”	  	 	6	  
	 1.40
	  	“EPIZYME IP”	  	 	7	  
	 1.41
	  	“EPIZYME Know-How”	  	 	7	  
	 1.42
	  	“EPIZYME Patents”	  	 	7	  

  
 - i -

							
	 1.43
	  	“EU”	  	 	7	  
	 1.44
	  	“Executive Officers”	  	 	7	  
	 1.45
	  	“EZH2”	  	 	7	  
	 1.46
	  	“EZH2 Compound(s)”	  	 	7	  
	 1.47
	  	“FDA”	  	 	7	  
	 1.48
	  	“Field”	  	 	8	  
	 1.49
	  	“First Commercial Sale”	  	 	8	  
	 1.50
	  	“FTE”	  	 	8	  
	 1.51
	  	“FTE Cost”	  	 	8	  
	 1.52
	  	“FTE Rate”	  	 	8	  
	 1.53
	  	“GLP Toxicology Study”	  	 	8	  
	 1.54
	  	“IND”	  	 	8	  
	 1.55
	  	“Indication”	  	 	9	  
	 1.56
	  	“Initiation”	  	 	9	  
	 1.57
	  	“Joint IP”	  	 	9	  
	 1.58
	  	“Joint Know-How”	  	 	9	  
	 1.59
	  	“Joint Patent(s)”	  	 	9	  
	 1.60
	  	“Know-How”	  	 	9	  
	 1.61
	  	“Law” or “Laws”	  	 	9	  
	 1.62
	  	“Lead Candidate”	  	 	9	  
	 1.63
	  	“Lead Candidate Criteria”	  	 	10	  
	 1.64
	  	“Licensed Compound(s)”	  	 	10	  
	 1.65
	  	“Licensed Product”	  	 	10	  
	 1.66
	  	“MAA”	  	 	10	  
	 1.67
	  	“Major EU Country”	  	 	10	  
	 1.68
	  	“Major Market Country(ies)”	  	 	10	  
	 1.69
	  	“Manufacture” or “Manufacturing”	  	 	10	  
	 1.70
	  	“MHLW”	  	 	10	  
	 1.71
	  	“NDA”	  	 	10	  
	 1.72
	  	“Net Sales”	  	 	10	  
	 1.73
	  	“Out-of-Pocket Costs”	  	 	12	  
	 1.74
	  	“Patents”	  	 	13	  
	 1.75
	  	“Patent-Based Exclusivity”	  	 	13	  
	 1.76
	  	“Person”	  	 	13	  
	 1.77
	  	“Phase 1 Clinical Trial”	  	 	13	  
	 1.78
	  	“Phase 2 Clinical Trial”	  	 	13	  
	 1.79
	  	“Phase 3 Clinical Trial”	  	 	13	  
	 1.80
	  	“Profit-Share Term”	  	 	13	  
	 1.81
	  	“Proof of Concept”	  	 	14	  
	 1.82
	  	“Prosecution and Maintenance” or “Prosecute and Maintain”	  	 	14	  
	 1.83
	  	“Regulatory Approval”	  	 	14	  
	 1.84
	  	“Regulatory Authority”	  	 	14	  
	 1.85
	  	“Regulatory-Based Exclusivity”	  	 	14	  
	 1.86
	  	“Regulatory Dossier”	  	 	14	  
	 1.87
	  	“Regulatory Materials”	  	 	15	  
	 1.88
	  	“Research and Development Plan”	  	 	15	  

  
 - ii -

							
	 1.89
	  	“Research Term”	  	 	15	  
	 1.90
	  	“ROW”	  	 	15	  
	 1.91
	  	“Sublicensee”	  	 	15	  
	 1.92
	  	“Territory”	  	 	15	  
	 1.93
	  	“Therapeutic Product”	  	 	15	  
	 1.94
	  	“Third Party”	  	 	15	  
	 1.95
	  	“UNC”	  	 	15	  
	 1.96
	  	“UNC License Agreement”	  	 	16	  
	 1.97
	  	“UNC Patent”	  	 	16	  
	 1.98
	  	“United States” or “U.S.”	  	 	16	  
	 1.99
	  	“Valid Claim”	  	 	16	  
	 1.100
	  	“Veterinary Product”	  	 	16	  
	 1.101
	  	Additional Definitions	  	 	16	  
		
	ARTICLE 2 COLLABORATION OVERVIEW; INITIAL DEVELOPMENT ACTIVITIES	  	 	18	  
	 2.1
	  	Collaboration Overview	  	 	18	  
	 2.2
	  	Research and Development Plan; Development Activities	  	 	18	  
	 2.3
	  	Lead Candidates; Development Candidates; Proof of Concept	  	 	19	  
	 2.4
	  	Reports; Results	  	 	20	  
	 2.5
	  	Subcontracting	  	 	20	  
	 2.6
	  	Regulatory Matters; Compliance	  	 	20	  
		
	ARTICLE 3 POST-PROOF OF CONCEPT ACTIVITIES	  	 	21	  
	 3.1
	  	Development and Commercialization	  	 	21	  
	 3.2
	  	EISAI Diligence	  	 	21	  
	 3.3
	  	Meetings	  	 	21	  
	 3.4
	  	Reports; Results	  	 	21	  
		
	ARTICLE 4 GOVERNANCE	  	 	22	  
	 4.1
	  	Joint Steering Committee	  	 	22	  
	 4.2
	  	Alliance Managers	  	 	25	  
	 4.3
	  	Senior Management Meetings	  	 	25	  
		
	ARTICLE 5 LICENSE GRANTS	  	 	25	  
	 5.1
	  	License Grant To EISAI	  	 	25	  
	 5.2
	  	Compliance with UNC License Agreement	  	 	26	  
	 5.3
	  	License Grants to EPIZYME	  	 	27	  
	 5.4
	  	Rights Retained by the Parties	  	 	27	  
	 5.5
	  	Section 365(n) of the Bankruptcy Code	  	 	28	  
	 5.6
	  	Access to Know-How	  	 	28	  
		
	 ARTICLE 6 EPIZYME PROFIT-SHARING OPTION; JOINT DEVELOPMENT AND COMMERCIALIZATION AGREEMENT
	  	 	29	  
	 6.1
	  	Epizyme Profit-Sharing Option	  	 	29	  
	 6.2
	  	Effects of Exercising Profit-Sharing Option	  	 	30	  
	 6.3
	  	Additional Past Development Costs	  	 	31	  

  
 - iii -

							
	ARTICLE 7 FINANCIAL TERMS	  	 	32	  
	 7.1
	  	Upfront Fee	  	 	32	  
	 7.2
	  	Research Funding	  	 	32	  
	 7.3
	  	Development Milestones	  	 	34	  
	 7.4
	  	Sales Milestones	  	 	35	  
	 7.5
	  	Licensed Product Royalties	  	 	36	  
	 7.6
	  	Profit Sharing	  	 	39	  
	 7.7
	  	Reports; Sales Milestones; Royalty Payments	  	 	40	  
	 7.8
	  	Methods of Payments	  	 	40	  
	 7.9
	  	Accounting	  	 	41	  
	 7.10
	  	Withholding Taxes	  	 	42	  
	 7.11
	  	Late Payments	  	 	42	  
	 7.12
	  	Limitations on Payments for [**] Use	  	 	42	  
		
	ARTICLE 8 EXCLUSIVITY; CHANGE OF CONTROL	  	 	43	  
	 8.1
	  	Target Exclusivity	  	 	43	  
	 8.2
	  	Exceptions	  	 	43	  
	 8.3
	  	Uncured Material Breach After Change of Control	  	 	45	  
		
	ARTICLE 9 INTELLECTUAL PROPERTY RIGHTS	  	 	45	  
	 9.1
	  	Ownership	  	 	45	  
	 9.2
	  	Prosecution and Maintenance of Patents	  	 	46	  
	 9.3
	  	Patent Costs	  	 	48	  
	 9.4
	  	Defense of Claims Brought by Third Parties	  	 	48	  
	 9.5
	  	Enforcement of EPIZYME Patents, Collaboration Patents and Joint Patents	  	 	48	  
	 9.6
	  	Coordination with UNC License Agreement	  	 	51	  
	 9.7
	  	Invalidity or Unenforceability Defenses or Actions	  	 	51	  
	 9.8
	  	Third Party Licenses	  	 	51	  
	 9.9
	  	Ownership and Prosecution of Product Trademarks	  	 	52	  
		
	ARTICLE 10 CONFIDENTIALITY	  	 	52	  
	 10.1
	  	Confidentiality; Exceptions	  	 	52	  
	 10.2
	  	Product Information	  	 	52	  
	 10.3
	  	Authorized Disclosure	  	 	53	  
	 10.4
	  	Press Release; Disclosure of Agreement	  	 	54	  
	 10.5
	  	Termination of Prior Confidentiality Agreement	  	 	55	  
	 10.6
	  	Remedies	  	 	55	  
	 10.7
	  	Publications	  	 	55	  
	 10.8
	  	Clinical Trial Register	  	 	56	  
	 10.9
	  	Use of Name	  	 	56	  
	 10.10
	  	Return of Confidential Information	  	 	56	  
		
	ARTICLE 11 REPRESENTATIONS AND WARRANTIES	  	 	57	  
	 11.1
	  	Representations and Warranties of Both Parties	  	 	57	  
	 11.2
	  	Representations and Warranties of EPIZYME	  	 	57	  
	 11.3
	  	Representation and Warranty of EISAI	  	 	60	  

  
 - iv -

							
	 11.4
	  	Mutual Covenants	  	 	60	  
	 11.5
	  	Disclaimer	  	 	61	  
		
	ARTICLE 12 INDEMNIFICATION; INSURANCE	  	 	61	  
	 12.1
	  	Indemnification by EISAI	  	 	61	  
	 12.2
	  	Indemnification by EPIZYME	  	 	62	  
	 12.3
	  	Procedure	  	 	63	  
	 12.4
	  	Insurance	  	 	63	  
	 12.5
	  	LIMITATION OF LIABILITY	  	 	64	  
		
	ARTICLE 13 TERM AND TERMINATION	  	 	64	  
	 13.1
	  	Term; Expiration	  	 	64	  
	 13.2
	  	Unilateral Termination by EISAI	  	 	65	  
	 13.3
	  	Termination for Cause	  	 	66	  
	 13.4
	  	Termination for EISAI Patent Challenge	  	 	67	  
	 13.5
	  	Effects of Termination	  	 	67	  
	 13.6
	  	Accrued Rights; Surviving Provisions	  	 	74	  
		
	ARTICLE 14 MISCELLANEOUS	  	 	75	  
	 14.1
	  	Dispute Resolution	  	 	75	  
	 14.2
	  	Arbitration Request	  	 	75	  
	 14.3
	  	Governing Law	  	 	76	  
	 14.4
	  	Assignment	  	 	76	  
	 14.5
	  	Performance Warranty	  	 	77	  
	 14.6
	  	Force Majeure	  	 	77	  
	 14.7
	  	Notices	  	 	77	  
	 14.8
	  	Export Clause	  	 	78	  
	 14.9
	  	Waiver	  	 	78	  
	 14.10
	  	Severability	  	 	79	  
	 14.11
	  	Entire Agreement	  	 	79	  
	 14.12
	  	Independent Contractors	  	 	79	  
	 14.13
	  	Non-solicitation of Key Employees	  	 	79	  
	 14.14
	  	Headings; Construction; Interpretation	  	 	80	  
	 14.15
	  	Books and Records	  	 	80	  
	 14.16
	  	Further Actions	  	 	80	  
	 14.17
	  	Parties in Interest	  	 	80	  
	 14.18
	  	Performance by Affiliates	  	 	80	  
	 14.19
	  	Counterparts	  	 	81	  

  

					
	 List of Exhibits

	 Exhibit A
	  	-	    	Development Candidate Selection Criteria
	 Exhibit B
	  	-	    	EPIZYME Patents (as of the Effective Date)
	 Exhibit C
	  	-	    	Lead Candidate Criteria
	 Exhibit D
	  	-	    	Initial Research and Development Plan
	 Exhibit E
	  	-	    	Joint Development and Commercialization Agreement Term Sheet
	 Exhibit F
	  	-	    	Press Release
	 Exhibit G
	  	-	    	Licensed Compounds (as of the Effective Date)

  
 - v -

 COLLABORATION AND LICENSE AGREEMENT 

This COLLABORATION AND LICENSE AGREEMENT (this “Agreement”) is entered into and made effective as of the 1st day of
April, 2011 (the “Effective Date”) by and between Epizyme, Inc., a Delaware corporation having its principal place of business at 840 Memorial Drive, Cambridge, Massachusetts 02139, U.S.A. (“EPIZYME”), and Eisai
Co., Ltd., a Japan corporation, having its principal place of business at Koishikawa 4-6-10, Bunkyo-Ku, Tokyo 112-8088, Japan (“EISAI”). EPIZYME and EISAI are each referred to herein by name or as a “Party” or,
collectively, as the “Parties.” 
 RECITALS 

WHEREAS, EPIZYME possesses proprietary technology and intellectual property to identify and develop novel, small molecule histone
methyltransferase (“HMT”) inhibitors; 
 WHEREAS, EISAI possesses expertise in the Development and
Commercialization (each as defined below) of human pharmaceuticals; 
 WHEREAS, EISAI and EPIZYME desire to engage in a
collaborative effort pursuant to which the Parties will carry out Development activities directed to EZH2 (as defined below), with the goal of identifying and Developing compounds directed to EZH2 using EPIZYME’s proprietary technology; and

 WHEREAS, EISAI desires to obtain exclusive rights from EPIZYME, and EPIZYME desires to grant such rights, to further Develop
and Commercialize such compounds directed to EZH2 for any and all uses in the Territory (as defined below) and, if EPIZYME exercises the Profit-Sharing Option (as defined below), to jointly Develop and Commercialize such compounds, all on the terms
and conditions set forth herein. 
 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 context dictates otherwise:

 1.1 “Affiliate” means, with respect to a Person, any other Person which, directly or indirectly through one
(1) or more intermediaries, controls, is controlled by or is under common control with such Person, regardless of whether such Affiliate is or becomes an Affiliate on or after the Effective Date. A Person shall be deemed to “control”
another Person if it (a) owns, directly or indirectly, beneficially or legally, more than fifty percent (50%) of the outstanding voting securities or capital stock of such other Person, or has other comparable ownership interest with
respect to any Person other than a corporation; or (b) has the power, whether pursuant to contract, ownership of securities or otherwise, to direct the management and policies of such other Person. 

 1.2 “Annual Net Sales” means total Net Sales in a country in the Territory
in a particular Calendar Year. 
 1.3 “Bayh-Dole Act” means the Patent and Trademark Law Amendments Act of
1980, as amended, codified at 35 U.S.C. §§ 200-212, as amended, as well as any regulations promulgated pursuant thereto, including in 37 C.F.R. § 401. 
 1.4 “Budget Year” means a period of twelve (12) consecutive months beginning on April 1 and ending on March 31. 

1.5 “Business Day” means a day on which banking institutions in Boston, Massachusetts are open for business, excluding
any Saturday or Sunday. 
 1.6 “Calendar Quarter” means a period of three (3) consecutive months ending on
the last day of March, June, September, or December, respectively. 
 1.7 “Calendar Year” means a period of
twelve (12) consecutive months beginning on January 1 and ending on December 31. 
 1.8 “cGMP”
means all Laws governing Manufacturing practices for intermediates, bulk products or finished products, including the regulations set forth in the FDA’s current Good Manufacturing Practices, 21 CFR Parts 210 and 211, and The Rules Governing
Medicinal Products in the European Community, Volume IV, Good Manufacturing Practice for Medicinal Products, as each may be amended from time to time. 
 1.9 “Change of Control Event” means (a) EPIZYME (i) merges or consolidates with any Third Party, or (ii) effects any other transaction or series of related transactions
involving the transfer of capital stock of EPIZYME to a Third Party, other than a transaction in which EPIZYME or underwriters for EPIZYME sell securities of EPIZYME (A) in a public offering, or (B) directly to bona fide venture capital
investors or bona fide institutional investors that routinely make such investments for the potential financial return on such investments and not with any view to acquisition, in the case of each of the foregoing clauses (i) and (ii) such
that the stockholders of EPIZYME immediately prior thereto, in the aggregate, no longer beneficially own more than fifty percent (50%) of the outstanding voting securities of the surviving entity or the ultimate parent of the surviving entity,
following the closing of such merger, consolidation, other transaction or series of related transactions; (b) EPIZYME sells all or substantially all of its business or assets to which this Agreement relates to a Third Party; or (c) any
“person” or “group” (as such terms are defined under Section 13(d) and 14(d) of the United States Securities Exchange Act of 1934) obtains control (as defined in Section 1.1) of EPIZYME. 

1.10 “Clinical Trial” means a Phase 1 Clinical Trial, Phase 2 Clinical Trial, Phase 3 Clinical Trial, or a study
incorporating more than one of these phases. 
 1.11 “Collaboration IP” means Collaboration Know-How and
Collaboration Patents. 
 1.12 “Collaboration Know-How” means EISAI Collaboration Know-How and EPIZYME
Collaboration Know-How. 

  
 - 2 -

 1.13 “Collaboration Patents” means EISAI Collaboration Patents and EPIZYME
Collaboration Patents. 
 1.14 “Commercialization” and “Commercialize” means all activities
undertaken with respect to a product relating to marketing, promotion (including advertising and detailing), medical affairs activities, medical science liaison activities, sponsored product or continuing medical education activities,
post-Regulatory Approval clinical studies (that are not required to obtain or maintain such Regulatory Approval), obtaining pricing and reimbursement approval, in each case with respect to such product, any importing, offering for sale, distribution
and sale of such product, identifying, screening or diagnosing patients as potential users of such product, interacting with Regulatory Authorities regarding the foregoing, and Manufacturing commercial supplies for the foregoing activities.

 1.15 “Commercialization Costs” means, with respect to Commercialization activities performed hereunder,
costs and expenses of the Parties and their Affiliates that are specifically associated with the conduct of such activities, including costs of consultants, agents and subcontractors. 

1.16 “Commercially Reasonable Efforts” means: 
 (a) with respect to EPIZYME, such efforts that are consistent with the efforts and resources normally used by EPIZYME in the exercise of its reasonable business discretion relating to the Development and
commercial progression of a potential pharmaceutical product: 
 (i) that is at a similar stage in its Development or product
life as the relevant Compound, Licensed Compound or Licensed Product; and 
 (ii) that has commercial and market potential
similar to the relevant Compound, 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 and profitability (including pricing and reimbursement status achieved or likely to be achieved); and 
 (b) with
respect to EISAI, such efforts that are consistent with the efforts and resources normally used by EISAI in the exercise of its reasonable business discretion relating to the Development and Commercialization of a potential pharmaceutical product:

 (i) that is at a similar stage in its Development or product life as the relevant Compound, Licensed Compound or Licensed
Product; and 
 (ii) that has commercial and market potential similar to the relevant Compound, 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 and profitability (including pricing and reimbursement
status achieved or likely to be achieved, and royalties and other payments required under this Agreement). 

  
 - 3 -

 “Commercially Reasonable Efforts” shall be determined on a country-by-country
basis, except that the Party may consider the impact of its efforts and resources expended with respect to any country on any other country. If either Party grants a sublicense or assigns its rights and obligations under this Agreement to an
Affiliate or Third Party as permitted under this Agreement, then, with respect to such Sublicensee, assignee or designee, Commercially Reasonable Efforts shall mean the efforts and resources (as defined above in this Section 1.16) normally used
by the Party granting the sublicense, assigning its rights and obligations, qualified by the items in clause (a)(i) – (ii), inclusive, if EPIZYME is the sublicensing, assigning or designating Party, and qualified by the items in clause (b)(i)
– (ii), inclusive, if EISAI is the sublicensing, assigning or designating Party. 
 1.17 “Comparable Third Party
Product” means, with respect to a Therapeutic Product in any country in the Territory, any pharmaceutical product sold by a Third Party not authorized by or on behalf of EISAI, its Affiliates or Sublicensees, that: 

(a) contains, as an active pharmaceutical ingredient, the same Compound as the Licensed Compound contained in the applicable Therapeutic
Product; and 
 (b) is approved by the applicable Regulatory Authority in such country for one or more of the same Indications
as the applicable Therapeutic Product. 
 1.18 “Comparable Third Party Product Competition” means, with respect
to a Therapeutic Product in any country in the Territory 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) have a market share of [**] percent ([**]%) or more of the aggregate market in such country
of such Therapeutic Product and the Comparable Third Party Product(s) collectively (based on sales of units of such Therapeutic 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 determined by EPIZYME and EISAI). As used herein, a “unit” of a product means the equivalent amount of product used for an equivalent treatment cycle of such product. 

1.19 “Compound(s)” means a small molecule HMT inhibitor. 

1.20 “Control”, “Controls” or “Controlled” means, with respect to any intellectual
property right or Know-How, possession of the right (whether through ownership or license (other than by operation of this Agreement) or control (as defined in Section 1.1) over an Affiliate with such right) to grant the licenses or sublicenses
under such intellectual property right or Know-How as provided herein without violating the terms of any agreement or other arrangement with any Third Party. Notwithstanding the foregoing, intellectual property rights or Know-How of a Party that is
licensed or otherwise acquired from a Third Party after the Effective Date and would otherwise be considered to be under the Control of a Party shall not be deemed to be under the Control of such Party if the application of such definition in the
context of any license grants or sublicenses under this Agreement would require the granting Party to 

  
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make additional payments or royalties to a Third Party in connection with such license or sublicense grants, unless the other Party agrees to pay the additional payments or royalties to the Third
Party (but subject to Sections 7.5.4(b) and 7.5.4(c)). 
 1.21 “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). 

1.22 “Develop” or “Development” means discovery, research, preclinical development, clinical
development with respect to a product, including identification, characterization, optimization, non-clinical testing, pharmacology studies, toxicology studies, formulation, chemical analysis, bioanalytical analysis, material performance studies
(such as measurements of stability, physical form, dissolution, or visual or spectroscopic analysis, and the like), Manufacturing process development and scale-up (including active pharmaceutical ingredient and drug product production),
Manufacturing pre-clinical and clinical supplies for the foregoing activities, quality assurance and quality control, technical support, pharmacokinetic studies, clinical studies, interacting with Regulatory Authorities regarding the foregoing, and
all other activities relating to seeking, obtaining or maintaining any Regulatory Approvals for such product from the FDA or any other applicable Regulatory Authority. 
 1.23 “Development Candidate” means a Compound directed to EZH2 that is designated by the JSC pursuant to Section 2.3.2 as meeting the applicable Development Candidate Selection
Criteria. 
 1.24 “Development Candidate Selection Criteria” means, with respect to a Compound, the criteria
set forth on Exhibit A, as such criteria may be amended by the JSC hereunder. 
 1.25 “Development
Costs” means, with respect to Development activities performed under the Research and Development Plan hereunder or otherwise performed by or on behalf of a Party hereunder, costs and expenses of the Parties and their Affiliates that are
specifically associated with the conduct of such activities, including Out-of Pocket Costs. For purposes of clarity, Development Costs shall not include any milestone payments from EISAI to EPIZYME hereunder. 

1.26 “Diagnostic Know-How” means Know-How that is necessary or reasonably useful to Develop or Commercialize any
Diagnostic Product in the Field in the Territory. 
 1.27 “Diagnostic Patents” means Patents claiming or
directed to Diagnostic Know-How. 
 1.28 “Diagnostic Product” means any biomarker or diagnostic assay or test
that is designed for use with, or that relates to, is associated with or is correlated with patient populations that do or do not respond to treatment with, a particular Therapeutic Product or Veterinary Product, as applicable. 

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

 1.30 “EISAI Collaboration IP” means EISAI Collaboration Know-How and EISAI Collaboration Patents.

 1.31 “EISAI Collaboration Know-How” means Know-How that is discovered, developed, invented, conceived or
reduced to practice solely by or on behalf of EISAI or its Affiliates or Sublicensees pursuant to the conduct of activities under the Collaboration or in the exercise of EISAI’s licenses under this Agreement (it being understood that any
activities carried out by or on behalf of EPIZYME, its Affiliates or Sublicensees under the Collaboration shall not be construed or interpreted to be carried out by or on behalf of EISAI, its Affiliates or Sublicensees for purposes hereof).

 1.32 “EISAI Collaboration Patents” means Patents claiming or directed to EISAI Collaboration Know-How.

 1.33 “EISAI IP” means EISAI Know-How and EISAI Patents. 

1.34 “EISAI Know-How” means Know-How that (a) is Controlled by EISAI as of the Effective Date or thereafter during
the Term, (b) arises outside of the Collaboration, and (c) is necessary or reasonably useful for the Development, Manufacture or Commercialization of Licensed Compounds and Licensed Products in the Field in the Territory. For purposes of
clarity, EISAI Know-How includes Diagnostic Know-How Controlled by EISAI, but excludes any Collaboration Know-How owned by EISAI and EISAI’s interest in any Joint Know-How. 

1.35 “EISAI Patent(s)” means Patents that (a) are Controlled by EISAI as of the Effective Date or thereafter during
the Term, (b) arise outside of the Collaboration, and (c) claim or are directed to EISAI Know-How. For purposes of clarity, EISAI Patents include Diagnostic Patents Controlled by EISAI, but exclude Collaboration Patents owned by EISAI and
EISAI’s interest in any Joint Patents. 
 1.36 “EMA” means the European Medicines Agency, and any
successor entity thereto. 
 1.37 “EPIZYME Collaboration IP” means EPIZYME Collaboration Know-How and EPIZYME
Collaboration Patents. 
 1.38 “EPIZYME Collaboration Know-How” means Know-How that is discovered, developed,
invented, conceived or reduced to practice solely by or on behalf of EPIZYME or its Affiliates or Sublicensees pursuant to the conduct of activities under the Collaboration or in the exercise of EPIZYME’s licenses under this Agreement (it being
understood that any activities carried out by or on behalf of EISAI, its Affiliates or Sublicensees under this Agreement shall not be construed or interpreted to be carried out by or on behalf of EPIZYME, its Affiliates or Sublicensees for purposes
hereof). 
 1.39 “EPIZYME Collaboration Patents” means Patents claiming or directed to EPIZYME Collaboration
Know-How. 

  
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 1.40 “EPIZYME IP” means EPIZYME Know-How and EPIZYME Patents. 

1.41 “EPIZYME Know-How” means Know-How that (a) is Controlled by EPIZYME as of the Effective Date or thereafter
during the Term, (b) arises outside of the Collaboration, and (c) is necessary or reasonably useful for the Development, Manufacture or Commercialization of Licensed Compounds and Licensed Products in the Field in the Territory. For
purposes of clarity, EPIZYME Know-How includes Diagnostic Know-How Controlled by EPIZYME, but excludes Collaboration Know-How owned by EPIZYME and EPIZYME’s interest in any Joint Know-How. 

1.42 “EPIZYME Patents” means: 
 (a) the patents and patent applications listed on Exhibit B; 
 (b) any
substitutions, divisionals, continuations, continuations-in-part, provisional applications, reissues, renewals, registrations, confirmations, re-examinations, extensions, supplementary protection certificates and the like of any patents or patent
applications set forth on Exhibit B; 
 (c) foreign counterparts of any of the foregoing in clause (a) or (b); and

 (d) Patents other than those included in the foregoing clauses (a) through (c) that are Controlled by EPIZYME as
of the Effective Date or thereafter during the Term and arise outside of the Collaboration, that claim or are directed to EPIZYME Know-How. 
 For purposes of clarity, EPIZYME Patents include Diagnostic Patents Controlled by EPIZYME, but exclude Collaboration Patents owned by EPIZYME and EPIZYME’s interest in any Joint Patents. 

1.43 “EU” means all countries that are officially recognized as member states of the European Union at any particular
time during the Term. 
 1.44 “Executive Officers” means EPIZYME’s Chief Executive Officer and
EISAI’s President of its Oncology Product Creation Unit. 
 1.45 “EZH2” means catalytic subunit of
Polycomb repressive complex 2 (PRC2), which is a highly conserved histone methyltransferase that targets lysine-27 of histone H3. 
 1.46 “EZH2 Compound(s)” means any Compound(s) that: 
 (a) is
directed to EZH2; and 
 (b) has an in vitro IC50 potency with a numerical value of [**] and [**] selectivity relative to
the next most active HMT target, other than EZH1. 
 1.47 “FDA” means the U.S. Food and Drug Administration,
and any successor entity thereto. 

  
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 1.48 “Field” means the treatment, prevention, palliation or diagnosis of
any human or veterinary disease, disorder or condition. 
 1.49 “First Commercial Sale” means, with respect to
each Licensed Product in a country in the Territory, the first sale for which revenue has been recognized by EISAI or its Affiliates or Sublicensees for use or consumption by the general public of such Licensed Product in such country after
Regulatory Approval (and pricing or reimbursement approval, if legally required for such sale) for such Licensed Product has been obtained in such country; 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, non-clinical activities
or other Development activities, or disposal or transfer of Licensed Products for a bona fide charitable purpose; and 
 (c)
treatment IND sales, named patient sales, or compassionate use. 
 1.50 “FTE” means the equivalent of the work
of one (1) employee full time for one (1) Calendar Year (consisting of at least a total of [**]hours per Calendar Year) of work performed by EPIZYME directly related to the Development activities under the Research and Development Plan
hereunder. 
 1.51 “FTE Cost” means, for any period, the product of (a) the actual total FTEs (or
applicable portion thereof) during such period, and (b) the FTE Rate. 
 1.52 “FTE
Rate” means, for the period commencing on the Effective Date and ending December 31, 2011, $[**] per FTE. On January 1, 2012 and on January 1st of each subsequent Calendar Year, the foregoing rate shall be increased for the Calendar Year then commencing by the
percentage increase, if any, in the CPI as of December 31 of the then most recently completed Calendar Year over the level of the CPI as of December 31 of the prior Calendar Year. As used in this Section 1.52, “CPI”
means the Consumer Price Index – Urban Wage Earners and Clerical Workers, US City Average, All Items, 1982-84 = 100, published by the United States Department of Labor, Bureau of Labor Statistics (or its successor equivalent index). 

1.53 “GLP Toxicology Study” means a toxicology study that is conducted in compliance with 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) (“GLP”) and is required to meet the requirements for filing an IND. 

1.54 “IND” means an investigational new drug application 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). 

  
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 1.55 “Indication” means any human disease or condition, or sign or symptom
of a human disease or condition. 
 1.56 “Initiation” means, with respect to a Clinical Trial, the first dosing
of the first subject enrolled in such Clinical Trial with a Therapeutic Product. 
 1.57 “Joint IP” means Joint
Know-How and Joint Patents. 
 1.58 “Joint Know-How” means Know-How that is jointly discovered, developed,
invented, conceived or reduced to practice by one or more employees, agents or consultants of EPIZYME, its Affiliates or Sublicensees, on the one hand, and one or more employees, agents or consultants of EISAI, its Affiliates of Sublicensees on the
other hand, pursuant to the conduct of activities under the Collaboration or in the exercise of each Party’s licenses under this Agreement. 
 1.59 “Joint Patent(s)” means Patents that claim or are directed to Joint Know-How. 
 1.60 “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, pre-clinical 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; and 
 (b) compositions of matter, cells,
cell lines, assays, animal models and physical, biological or chemical material; 
 in each case ((a) and (b)) that is not generally known.

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

1.61 “Law” or “Laws” means all applicable 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. 
 1.62 “Lead Candidate” means a Compound directed to EZH2 that is selected by the JSC pursuant to Section 2.3.1 as meeting the applicable Lead Candidate Criteria. 

  
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 1.63 “Lead Candidate Criteria” means, with respect to a Compound, the
criteria set forth on Exhibit C. 
 1.64 “Licensed Compound(s)” means any EZH2 Compound(s) that is:

 (a) synthesized or identified 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) or jointly by or on behalf of the Parties in the conduct of the Collaboration or in the exercise of such Party’s licenses under this Agreement, including Compounds Controlled by either
Party and identified as EZH2 Compounds in the conduct of the Collaboration or in the exercise of a Party’s licenses under this Agreement; or 
 (b) otherwise Controlled by EPIZYME as of the Effective Date or thereafter during the Term. 
 1.65 “Licensed Product” means any Therapeutic Product, any Diagnostic Product or any Veterinary Product, as applicable. For avoidance of doubt, except as otherwise expressly set forth in
this Agreement, Licensed Product includes any Shared Product. 
 1.66 “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. 
 1.67 “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.

 1.68 “Major Market Country(ies)” means (a) the United States, (b) Japan or (c) one (or more)
of the Major EU Countries. 
 1.69 “Manufacture” or “Manufacturing” means, as applicable, all
activities associated with the production, manufacture, supply, processing, filling, packaging, labeling, shipping, and storage of a Licensed Compound, Licensed 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. 
 1.70 “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. 
 1.71 “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 filed with the FDA, or
any equivalent filing, including an MAA, in a country or regulatory jurisdiction other than the United States. 
 1.72
“Net Sales” means with respect to any Licensed Product for any period, the gross amounts invoiced by EISAI, its Affiliates and Sublicensees (each, a “Selling Party”) to Third

  
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Party customers for sales of such Licensed Product during such period, less the following deductions actually incurred, allowed, paid, accrued or specifically allocated in its financial
statements in accordance with GAAP, for: 
 (a) customary and reasonable trade, quantity, and cash discounts, wholesaler
allowances and inventory management fees; 
 (b) customary and reasonable credits, rebates and chargebacks (including those to
managed-care entities and government agencies), and allowances or credits to customers on account of rejection or returns (including wholesaler and retailer returns) or on account of retroactive price reductions affecting such Licensed Product;

 (c) freight, postage and duties, and transportation charges relating to such Licensed Product, including handling and
insurance therefor; 
 (d) sales (such as VAT or its equivalent) and excise taxes, other consumption taxes, and customs duties
(excluding any taxes paid on the income from such sales) to the extent the Selling Party is not otherwise entitled to a credit or a refund for such taxes, duties or payments made; and 

(e) amounts previously included in Net Sales that are written-off by the Selling Party as uncollectible in accordance with the standard
practices of such Selling Party for writing off uncollectible amounts, consistently applied; provided, however, that if any such written-off amounts are subsequently collected, such collected amounts shall be included in Net
Sales in the period in which they are subsequently collected. 
 If non-monetary consideration is received for any Licensed
Product in any country, Net Sales will be calculated based on the average price charged for such Licensed Product in such country during the preceding Calendar Quarter, or in the absence of such sales, the fair market value of the Licensed Product
in such country, as determined by the Parties in good faith. If the Parties are unable to reach such an agreement, the Parties will refer such matter to a jointly selected Third Party with expertise in the pricing of pharmaceutical products that is
not 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. If the Parties are unable to agree on such a Third Party expert within [**]
days after a Party has notified the other Party that it desires to refer such matter to such a Third Party for resolution, either Party may request that the New York, New York office of the American Arbitration Association (“AAA”)
appoint such an expert to resolve such matter. The resolution determined by any such expert that is either jointly selected or appointed by the AAA shall be final and binding on the Parties. Notwithstanding anything to the contrary herein, the
transfer, disposal or use of Licensed Product, without consideration, for marketing, regulatory, development or charitable purposes, such as sampling, clinical trials, preclinical trials, compassionate use, named patient use, or indigent patient
programs, shall not be deemed a sale hereunder. 
 Net Sales shall be determined on, and only on, the first sale by a Party or
any of its Affiliate or Sublicensees to a non-Sublicensee Third Party. 

  
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 Eisai shall not, and shall cause its Selling Parties not to, use any Licensed Product as a
loss leader or otherwise unfairly or inappropriately discount the gross invoiced sales price of a Licensed Product in a manner that is intended to benefit, or provide an incentive to enhance sales of, any other pharmaceutical product sold by Eisai
or any of its Selling Parties. Sales of a Licensed Product between Eisai and any of its Selling Parties for resale shall be excluded from the computation of Net Sales, but the subsequent resale of such Licensed Product to a non-Sublicensee Third
Party shall be included within the computation of Net Sales. 
 If a Therapeutic Product is sold as part of a Combination
Product (as defined below) in any country, Net Sales for such country for any period will be the product of (i) Net Sales of the Combination Product calculated as above in such country for such period (i.e., calculated as for a
non-Combination Product) and (ii) the fraction (A/(A+B)), where: 
 “A” is the average wholesale acquisition cost
in such country of the Therapeutic Product comprising a Licensed Compound as the sole therapeutically active ingredient during such period; and 
 “B” is the average wholesale acquisition cost in such country of the other therapeutically active ingredients contained in the Combination Product when sold separately during such period.

 If “A” or “B” cannot be determined by reference to non-Combination Product sales as described above, then
Net Sales for purposes of determining royalty payments will be calculated as above, but the average wholesale acquisition cost 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, then the Parties will refer such matter to a jointly selected Third Party with expertise in the pricing of pharmaceutical
products that is not 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. If the Parties are unable to agree on such a Third Party
expert within [**] days after a Party has notified the other Party that it desires to refer such matter to such a Third Party for resolution, either Party may request that the New York, New York office of the AAA appoint such an expert to resolve
such matter. The resolution determined by any such expert that is either jointly selected or appointed by the AAA shall be final and binding on the Parties. 
 As used in this Section 1.72, “Combination Product” means a Therapeutic Product that contains one or more additional active ingredients (whether coformulated or copackaged) that are
not Licensed Compounds. Pharmaceutical dosage form vehicles, adjuvants and excipients shall be deemed not to be “active ingredients.” 
 1.73 “Out-of-Pocket Costs” means, with respect to Development activities performed under the Research and Development Plan by or on behalf of a Party hereunder, out-of-pocket expenses of
the Parties and Affiliates that are specifically associated with the conduct of such activities, including costs of consultants, agents and subcontractors and filing fees with Regulatory Authorities. 

  
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 1.74 “Patents” means (a) all national, regional and international
patents and patent applications, including provisional patent applications, (b) all patent applications filed either from such patents, patent applications or provisional applications or from an application claiming priority from either of
these, including divisionals, continuations, continuations-in-part, provisionals, converted provisionals and continued prosecution applications, (c) any and all patents that have issued or in the future issue from the foregoing patent
applications ((a) and (b)), including utility models, petty patents and design patents and certificates of invention, (d) any and all extensions or restorations by existing or future extension or restoration mechanisms, including revalidations,
reissues, re-examinations and extensions (including any supplementary protection certificates and the like) of the foregoing patents or patent applications ((a), (b), and (c)), and (e) any similar rights, including so-called pipeline protection
or any importation, revalidation, confirmation or introduction patent or registration patent or patent of additions to any of such foregoing patent applications and patents. 
 1.75 “Patent-Based Exclusivity” means, with respect to a Licensed Product in a country in the Territory, that at least one Valid Claim of the EPIZYME Patents, the EISAI Patents that Cover
the composition of matter of EZH2 Compounds, the Collaboration Patents or the Joint Patents Covers such Licensed Product in such country. 
 1.76 “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. 
 1.77 “Phase 1 Clinical Trial” means a human
clinical trial of a product in any country, the principal purpose of which is a preliminary determination of safety in healthy individuals or patients, that would satisfy the requirements of 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. 
 1.78 “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 initial
evidence of clinical safety and activity in a target patient population, or a similar clinical study prescribed by the relevant Regulatory Authorities in a country other than the United States. 

1.79 “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 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. 
 1.80 “Profit-Share Term”
means, as to each Shared Product, the period commencing upon the date of EPIZYME’s exercise of the applicable Profit-Sharing Option and continuing until the earlier of (a) such time as the applicable Joint Development and Commercialization
Agreement expires or is earlier terminated in accordance with its terms, or (b) such time as the applicable Shared Product is no longer being Developed or Commercialized in or for the United States and the Parties have agreed to permanently
cease such activities. 

  
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 1.81 “Proof of Concept” means, with respect to a Licensed Compound,
achievement of clinical results in a Phase 2 Clinical Trial demonstrating efficacy in a target population with a dose and administration schedule that would be pursued in a registration study towards a label-identified indication in the target
population. The specific criteria used to determine whether Proof of Concept has been achieved with respect to a Licensed Compound shall be established by the JSC at the appropriate stage of Development hereunder, and the JSC shall determine whether
Proof of Concept has been achieved with respect to such Licensed Compound based on such criteria. 
 1.82 “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 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 defense or enforcement actions taken with respect to a Patent. 

1.83 “Regulatory Approval” means, with respect to a country in the Territory, the approval, license or authorization of
the applicable Regulatory Authority(ies) necessary for the marketing and sale of a pharmaceutical product for a particular Indication in such country in the Territory, excluding separate pricing or reimbursement approvals that may be required.

 1.84 “Regulatory Authority” means, with respect to a country in the Territory, any national, regional, state
or local regulatory agency, department, bureau, commission, council or other governmental entity that regulates or otherwise exercises authority with respect to the Development, Manufacture, marketing, sale, distribution, use or other exploitation
of pharmaceutical products in such country, including the FDA, the EMA and the MHLW, and any successor(s) thereto. 
 1.85
“Regulatory-Based Exclusivity” means, with respect to a Licensed Product in a country in the Territory, that (a) EISAI 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 EISAI 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.

 1.86 “Regulatory Dossier” means the technical, medical and scientific registrations, authorizations and
approvals (including approvals of NDAs, supplements and amendments, pre- and post- approvals, pricing and Third Party reimbursement approvals, and labeling approvals) 

  
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of any Regulatory Authority necessary for the Development (including the conduct of clinical studies), Manufacture, distribution, marketing, promotion, offer for sale, use, import, reimbursement,
export or sale of a product in a 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 Regulatory
Materials and drug master file(s) (if any). 
 1.87 “Regulatory Materials” means regulatory
applications, notifications, registrations, Regulatory Approvals or other submissions made to or with a Regulatory Authority that are necessary or reasonably desirable in order to Develop, Manufacture, market, sell or otherwise Commercialize a
product in a particular country, territory or possession. Regulatory Materials include INDs, CTAs, NDAs and MAAs, and amendments and supplements to any of the foregoing, and applications for pricing approvals. 

1.88 “Research and Development Plan” means the research and development plan attached hereto as Exhibit D, which
plan shall include Development activities of the Parties with respect to Therapeutic Product(s) and related Diagnostic Product(s), as such plan may be amended from time to time in accordance with the terms hereof. 

1.89 “Research Term” means, unless otherwise agreed by the Parties, the period commencing upon the Effective Date and
continuing through December 31, 2014, unless this Agreement is earlier terminated. 
 1.90 “ROW” means all
countries in the Territory, except the U.S. 
 1.91 “Sublicensee” means (a) with respect to EISAI, a Third
Party to whom EISAI has granted a license under Know-How or Patents Controlled by EISAI, or a sublicense pursuant to Section 5.1.2 under Know-How or Patents licensed to EISAI pursuant to Section 5.1.1 of this Agreement, to Develop or
Commercialize Licensed Compounds or Licensed Products in the Field, excluding any Third Party acting solely as a distributor 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 pursuant to Section 5.3.2 under Know-How or Patents licensed to EPIZYME pursuant to Section 5.3.1 of this Agreement, to perform EPIZYME’s obligations under and in accordance with the Research and
Development Plan. 
 1.92 “Territory” means the entire world, but shall exclude the Terminated Territory(ies).

 1.93 “Therapeutic Product” means any human therapeutic, prophylactic or palliative pharmaceutical product
comprising a Licensed Compound, whether or not as the sole active ingredient, and in any dosage form or formulation. 
 1.94
“Third Party” means any Person other than EPIZYME or EISAI that is not an Affiliate of EPIZYME or of EISAI. 

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

  
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 1.96 “UNC License Agreement” means the License Agreement, dated
January 7, 2008, between UNC and EPIZYME. 
 1.97 “UNC Patent” means any Patent licensed to EPIZYME under
the UNC License Agreement that is sublicensed to EISAI under Section 5.1.1. 
 1.98 “United States” or
“U.S.” means the United States of America and all of its territories and possessions. 
 1.99 “Valid
Claim” means: 
 (a) a claim of an issued patent in the U.S. or in a jurisdiction outside the U.S., that has not
expired, lapsed, been cancelled or abandoned, or been dedicated to the public, disclaimed, or held unenforceable, invalid, 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 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. 
 1.100 “Veterinary Product” means
any therapeutic, prophylactic or palliative pharmaceutical product comprising a Licensed Compound, whether or not as the sole active ingredient, for veterinary use and in any dosage form or formulation. 

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

  

			
	 Definition:
	  	Section:
	 AAA
	  	1.72
	 Alliance Manager
	  	4.2
	 Arbitration Request
	  	14.2
	 Breaching Party
	  	13.3.1(a)
	 Budgeted Costs
	  	7.2.2(a)
	 Chairperson
	  	4.1.1
	 Claims
	  	12.1
	 Collaboration
	  	2.1
	 Combination Product
	  	1.72
	 Competing Business
	  	8.2.1
	 Competitive Infringement
	  	9.5.1
	 Compulsory Third Party Product
	  	7.5.3

  
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	 Definition:
	  	Section:
	 Confidential Information
	  	10.1
	 Cost of Goods
	  	Exhibit E
	 Cost Overrun
	  	7.2.2(d)
	 CPI
	  	1.52
	 CREATE Act
	  	9.2.6
	 CTA
	  	1.54
	 Current Lead Series
	  	2.2.1(a)
	 Disclosing Party
	  	10.1
	 EISAI
	  	Preamble
	 EISAI Patent Challenge
	  	13.4(b)
	 EPIZYME
	  	Preamble
	 EPIZYME’s Reimbursement Amount
	  	7.2.3
	 Excess Overrun
	  	7.2.2(e)
	 Existing Confidentiality Agreement
	  	10.5
	 Existing Know-How
	  	11.2.3
	 Existing Patents
	  	11.2.1
	 FFDCA
	  	11.1.6
	 GAAP
	  	14.15
	 GLP
	  	1.53
	 HMT
	  	Recitals
	 Indemnified Party
	  	12.3.1
	 Indemnifying Party
	  	12.3.1
	 In-Licensed Know-How
	  	11.2.3
	 In-Licensed Patents
	  	11.2.4
	 Joint Development and Commercialization Agreement
	  	6.1.1
	 Joint Development Plan
	  	Exhibit E
	 JSC
	  	4.1
	 Key Employee
	  	14.13
	 Losses
	  	12.1
	 Marketing-Related Materials
	  	13.5.1(g)
	 Net Profits/Losses
	  	Exhibit E
	 Non-Breaching Party
	  	13.3.1(a)
	 Notice of Exercise
	  	6.1.3
	 Option Exercise Period
	  	6.1.3
	 Owned Patents
	  	11.2.4
	 Party or Parties
	  	Preamble
	 Past Development Costs
	  	7.2.3
	 Payee
	  	7.8
	 Payor
	  	7.8
	 Product Information
	  	10.2
	 Profit-Sharing Option
	  	6.1.1
	 Receiving Party
	  	10.1
	 Royalty Term
	  	7.5.2(a)
	 Selling Party
	  	1.72
	 Severed Clause
	  	14.10

  
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	 Definition:
	  	Section:
	 Shared Commercialization Costs
	  	Exhibit E
	 Shared Development Costs
	  	Exhibit E
	 Shared Product
	  	6.2(a)
	 Subcommittee
	  	4.1.6
	 Term
	  	13.1.1
	 Terminated Territory
	  	13.5.2
	 Third Party Technical Expert
	  	4.1.5

 ARTICLE 2 
 COLLABORATION OVERVIEW; INITIAL DEVELOPMENT ACTIVITIES 
 2.1
Collaboration Overview. Pursuant to this Agreement (including the Research and Development Plan) and as further provided in this Article 2 and in Article 6, the Parties shall collaborate on the conduct of Development activities through Proof
of Concept of a Licensed Compound and, if EPIZYME exercises the Profit-Sharing Option with respect to the applicable Licensed Compound, subsequent joint Development and joint Commercialization of Shared Product in the United States, on a Shared
Product-by-Shared Product basis (the “Collaboration”). The Research and Development Plan may be amended or updated from time to time in accordance with Section 2.2.1. 

2.2 Research and Development Plan; Development Activities. 

2.2.1 Research and Development Plan. 
 (a) An initial Research and Development Plan, attached hereto as Exhibit D, sets forth certain Development (including Manufacturing) activities to be performed by each of the Parties during the
Research Term directed to one or more Compounds identified as part of the Current Lead Series on Exhibit G attached hereto (such Compounds may be referred to herein as the “Current Lead Series”). Following the Effective Date
and during the Research Term, the Parties shall mutually agree on any additional Development activities to be performed by the Parties beyond those necessary for the Current Lead Series to attain the Development Candidate Selection Criteria, which
Development activities shall be included in the Research and Development Plan. Such additional activities may include the Development of companion diagnostics and biomarkers as the Parties deem appropriate. Subject to EPIZYME’s exercise of the
applicable Profit-Sharing Option and the terms of any applicable Joint Development and Commercialization Agreement, the Research and Development Plan shall set forth, and EISAI will have the sole right and responsibility for, all Development
activities following the end of the Research Term unless the Parties otherwise mutually agree. 
 (b) The Research and
Development Plan shall be updated no later than [**] months prior to the [**] anniversary of the Effective Date to cover the Development activities to be performed by the Parties during the then-remaining portion of the Research Term. Any amendments
or updates to the Research and Development Plan during the Research Term shall be subject to mutual agreement of the Parties through the JSC. EISAI shall have the right in its sole discretion to amend or update the Research and Development Plan from
time to time after the Research Term; provided that EISAI shall provide EPIZYME with all such amendments or 

  
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updates, and provided, further, that, EISAI shall reasonably consider EPIZYME’s comments and input with respect to the Research and Development Plan in formulating such amendments or
updates. For the avoidance of doubt, EPIZYME shall not have any obligation to agree to any amendment or update to the Research and Development Plan that would impose Development responsibilities on EPIZYME beyond the Research Term. The Research and
Development Plan shall include a Development budget for the Research Term, as contemplated in Section 7.2.2(a). 
 2.2.2
Responsibilities. 
 (a) EPIZYME Responsibilities. 

(i) EPIZYME shall use Commercially Reasonable Efforts to perform the Development activities assigned to EPIZYME under the Research and
Development Plan. 
 (ii) Subject to the foregoing obligations to use Commercially Reasonable Efforts, EPIZYME provides no
representation, warranty or guarantee that the Collaboration will be successful, that any Lead Candidate Criteria or Development Candidate Selection Criteria will be achieved, that Proof of Concept will be achieved, or that any other particular
results will be achieved with respect to the Collaboration, EZH2, or any Compound, Licensed Compound or Licensed Product hereunder. 
 (b) EISAI Responsibilities. EISAI shall use Commercially Reasonable Efforts to perform the Development activities assigned to EISAI under the Research and Development Plan. 

(c) Operational Control. Notwithstanding anything in this Agreement to the contrary, the Party specifically designated as being
responsible for a particular activity under the Research and Development Plan shall have operational control over such activity. 
 2.3 Lead Candidates; Development Candidates; Proof of Concept. 
 2.3.1
Selection of Lead Candidate. The JSC shall determine whether any Compound satisfies the Lead Candidate Criteria and, upon the JSC’s determination that any Compound satisfies the Lead Candidate Criteria, such Compound shall be deemed a
Lead Candidate for all purposes hereunder and shall be progressed into further Development under the Collaboration in accordance with the Research and Development Plan; provided that, as of the Effective Date, the Current Lead Series
shall be deemed to include Compounds that satisfy the Lead Candidate Criteria. 
 2.3.2 Selection of Development
Candidate. The JSC shall determine whether any Compound satisfies the applicable Development Candidate Selection Criteria. Upon the JSC’s determination that any Compound satisfies the applicable Development Candidate Selection Criteria,
such Compound shall be deemed a Development Candidate for all purposes hereunder, with the expectation that a GLP Toxicology Study shall be commenced using such Development Candidate. In no event shall a GLP Toxicology Study for a Compound be
commenced prior to the determination by the JSC that such Compound satisfies the applicable Development Candidate Selection Criteria without the prior written consent of EISAI. 

  
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 2.3.3 Proof of Concept. The JSC shall determine whether Proof of Concept has been
achieved with respect to any Licensed Compound. 
 2.3.4 No Other EPIZYME Activities. For purposes of clarity, except as
otherwise set forth in a Joint Development and Commercialization Agreement with respect to a Shared Product, EPIZYME shall not be obligated to conduct Development activities beyond those contemplated under the Research and Development Plan,
regardless of whether any Compound identified or Developed under the Collaboration fails to meet the applicable Lead Candidate Criteria or Development Candidate Selection Criteria and regardless of whether Proof of Concept is achieved. For clarity,
EISAI shall have the right, but not the obligation, to conduct, at its sole expense (but subject to Section 7.2.3), any Development activities with respect to any Compound, Licensed Compound or Licensed Product assigned to EPIZYME under the
Research and Development Plan that are not performed by EPIZYME. 
 2.4 Reports; Results. Until achievement of Proof of
Concept of a Licensed Compound, each Party shall provide [**] written progress reports on the status of its Development activities under the Collaboration, including summaries of data and results associated with such Development activities, progress
toward completing milestones in Section 7.3 hereof, and, with respect to EISAI, all information described in Section 6.1.2 for the period covered by such report, at least [**] Business Days in advance of each JSC meeting. 

2.5 Subcontracting. Subject to the terms of this Agreement, each Party shall have the right to engage Affiliates or Third Party
subcontractors to perform 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; provided that any Party engaging an Affiliate or subcontractor hereunder shall remain responsible and obligated for such activities. 

2.6 Regulatory Matters; Compliance. 
 2.6.1 Compliance. Each Party agrees that in performing its obligations under this Agreement, it shall perform such obligations in good scientific manner and comply in all material respects with all
applicable FDA and other current international regulatory requirements and standards, including FDA’s cGMP, GLP and good clinical practices, and comparable foreign regulatory standards, and other Laws. 

2.6.2 Data Integrity. Each Party shall maintain, or cause to be maintained, records of its Development activities in accordance
with Law, in sufficient detail and accuracy and in good scientific manner appropriate for patent and regulatory purposes, and properly reflecting all work done and results achieved in the performance of its Development activities. Such records shall
be retained by each Party for at least [**] years after the termination of this Agreement, or for such longer period as may be required by Law. Each Party shall have the right, during normal business hours and upon reasonable notice, to inspect and
copy any such records, except to the extent that a Party reasonably determines that such records contain Confidential Information that is not licensed to the other Party, or to which the other Party does not otherwise have a right hereunder.

  
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 2.6.3 Regulatory Filings and Data. EISAI shall have the right and responsibility, in
consultation with EPIZYME, for preparing, filing and maintaining all regulatory filings and Regulatory Approvals necessary for the Development or Commercialization of Licensed Compounds or Licensed Products in the Field in the Territory, including
applicable INDs and NDAs. EISAI shall own all such regulatory filings and Regulatory Approvals. 
 2.6.4 Adverse Event
Reporting; Global Safety Database. Unless otherwise set forth in the applicable Joint Development and Commercialization Agreement, EISAI shall be solely responsible for reporting to applicable Regulatory Authorities all adverse drug experiences
associated with Licensed Compounds and Licensed Products in the Field in the Territory, and for establishing, holding and maintaining the global safety database for Licensed Compounds and Licensed Products in the Field in the Territory. 

ARTICLE 3 

POST-PROOF OF CONCEPT ACTIVITIES 
 3.1 Development and Commercialization. On a Licensed Compound-by-Licensed Compound basis, after the achievement of Proof of Concept of a Licensed Compound, EISAI, either itself or by and through
its Affiliates, Sublicensees or contractors, shall, subject to Article 6 and EPIZYME’s exercise of the Profit-Sharing Option with respect to such Licensed Compound, have the sole right and responsibility for all Development and
Commercialization activities in connection with such Licensed Compound, any Therapeutic Product or Veterinary Product comprising such Licensed Compound and any related Diagnostic Product(s) in the Field in the Territory. EISAI shall book all sales
of Licensed Products in the Territory. 
 3.2 EISAI Diligence. After the Research Term, EISAI shall use Commercially
Reasonable Efforts (itself or through an Affiliate or Sublicensee) to Develop, obtain Regulatory Approval for and Commercialize at least one (1) Therapeutic Product in each of the United States (subject to 6.2(d)), Japan and the Major EU
Countries. For clarity, EISAI shall not have any obligation to use Commercially Reasonable Efforts to Develop, obtain Regulatory Approval for or Commercialize more than one (1) Therapeutic Product in any of the United States, Japan and the
Major EU Countries. 
 3.3 Meetings. Without limiting the generality of any of the foregoing in this Article 3, after
achievement of Proof of Concept of a Licensed Compound, the Parties shall meet in person every [**] months, at a time and location to be mutually agreed by the Parties, to discuss the status of, and any updates with respect to, EISAI’s efforts
to Develop and Commercialize such Licensed Compound, any Therapeutic Product or Veterinary Product comprising such Licensed Compound and any related Diagnostic Product(s) (in each case excluding Shared Products, which are addressed in Article 6),
including to review and discuss the reports provided pursuant to Section 3.4 below. 
 3.4 Reports; Results. After
achievement of Proof of Concept of a Licensed Compound, EISAI shall provide EPIZYME with periodic written reports summarizing in reasonable detail (to the extent applicable) the material activities and anticipated plans of EISAI, its Affiliates and
Sublicensees with respect to the Development and Commercialization of such 

  
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Licensed Compound, any Therapeutic Product or Veterinary Product comprising such Licensed Compound and any related Diagnostic Product(s) (in each case excluding Shared Products, which are
addressed in Article 6) in the Field in the Territory, by each Major Market Country and the rest of the world in which the foregoing activities are conducted, such information to be provided for each Licensed Compound. Such written reports shall be
provided to EPIZYME at least once every [**] months (and reasonably in advance of each [**] meeting of the Parties held in accordance with Section 3.3). 
 ARTICLE 4 
 GOVERNANCE 

4.1 Joint Steering Committee. As soon as possible (but no later than [**] days) after the Effective Date, the Parties shall
establish a joint steering committee (the “JSC”) as more fully described in this Section 4.1. The JSC shall have review, oversight and decision-making responsibilities as more specifically provided herein. Each Party agrees to
keep the JSC informed of its progress and activities under the Collaboration. The JSC may establish Subcommittees as set forth in Section 4.1.6. 
 4.1.1 Membership. The JSC shall be comprised of [**] representatives (or such other number of representatives as the Parties may agree) from each of EISAI and EPIZYME. Each Party shall provide the
other with a list of its initial members of the JSC as soon as possible (but no later than [**] days) following the Effective Date. Each Party may replace any or all of its representatives on the JSC at any time upon written notice to the other
Party. Each representative of a Party shall have sufficient seniority and expertise in the biotechnology and pharmaceutical industry to participate on the JSC. Any member of the JSC may designate a substitute to attend and perform the functions of
that member at any meeting of the JSC, provided that such substitute meets the foregoing qualifications. Each Party may, subject to the other Party’s prior approval, invite non-member representatives of such Party to attend
meetings of the JSC as non-voting participants, subject to the confidentiality obligations of Article 10. The Parties shall designate a chairperson (the “Chairperson”) to oversee the operation of the JSC. The first Chairperson shall
serve until March 31, 2012, and each succeeding Chairperson shall serve for one (1) Budget Year. The right to name the Chairperson shall alternate between the Parties, with [**] designating the first Chairperson. 

4.1.2 Meetings. 
 (a) The first scheduled meeting of the JSC shall be held as soon as possible (but no later than [**] days) after the Effective Date. Thereafter, the JSC shall meet at least [**] each Calendar Quarter, or
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. Members of the JSC may attend a meeting either in person or by telephone, video conference
or similar means in which each participant can hear what is said by, and be heard by, the other participants; provided that at least [**] per Calendar Year shall be held in person. 

(b) After achievement of Proof of Concept of a Licensed Compound, the JSC shall disband; provided, however, that
after the Research Term, if the JSC has not previously disbanded, EPIZYME shall have the right, at EPIZYME’s sole discretion, to discontinue its 

  
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participation on, and not appoint members to, the JSC (or any Subcommittee), in which event EISAI may unilaterally discharge the responsibilities of the JSC (or the applicable Subcommittee for
which members were not appointed). If EPIZYME elects to discontinue its participation on the JSC after the Research Term, EPIZYME shall provide to EISAI, for a mutually-agreed period of time following the end of the Research Term, consultation and
advice as reasonably required with respect to EISAI’s Development activities directed to Licensed Compounds and Licensed Products in the Field in the Territory. Such consultation and advice, if provided via teleconference or videoconference,
shall be provided at no additional cost to EISAI and, if provided in person at EISAI’s facilities as may be mutually agreed by the Parties, shall be provided subject to EISAI’s payment of EPIZYME’s travel expenses associated with the
provision of such consultation and advice. For clarity, the JSC established pursuant to this Agreement shall be distinct from the JSC established pursuant to any Joint Development and Commercialization Agreement. 

(c) Meetings of the JSC that are held in person shall alternate between the offices of the Parties, or such other location as the
Parties may agree, with the first meeting held at the offices of [**]. The members of the JSC also may convene or be polled or consulted from time to time by electronic mail or correspondence, as deemed necessary or appropriate. A quorum of the JSC
shall exist whenever there is present at a meeting at least [**] appointed by each Party. Each Party will bear all expenses it incurs in regard to participating in all meetings of the JSC, including all travel and living expenses. 

4.1.3 Minutes. The Alliance Manager from the Party other than the Party of the Chairperson, shall be responsible for preparing and
circulating minutes of each meeting of the JSC, setting forth, inter alia, an overview of the discussions at the meeting and a list of any actions, decisions or determinations approved by the JSC and a list of any issues to be resolved by the
Executive Officers pursuant to Section 4.1.5. Such minutes shall be effective only after approval by both Parties in writing (which may be by electronic mail). 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 4.1.5, definitive minutes of all JSC meetings shall be finalized no later than [**] days after the meeting to which the minutes pertain. 

4.1.4 Responsibilities. The JSC shall perform the following functions: 

(a) review and monitor progress of the Collaboration; 
 (b) determine whether the applicable Development Candidate Selection Criteria has been achieved with respect to any Compound; 
 (c) establish the criteria for determining Proof of Concept; 
 (d) determine
whether Proof of Concept has been achieved with respect to any Licensed Compound; 
 (e) serve as a forum for exchange of
information and to facilitate discussions regarding the conduct of the Collaboration hereunder; 

  
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 (f) review and, during the Research Term, approve amendments to the Research and
Development Plan; including the annual budget therefor as described in Section 7.2.2(a); 
 (g) attempt to resolve any
disputes in any Subcommittee; and 
 (h) such other responsibilities as may be assigned to the JSC pursuant to this Agreement
or as may be mutually agreed upon by the Parties from time to time. 
 Each Party shall retain the rights, powers, and discretion granted to it
under this Agreement and no such rights, powers, or discretion shall be delegated to or vested in the JSC unless such delegation or vesting of rights is expressly provided for in this Agreement or the Parties expressly so agree in writing. For
clarity, the JSC shall not have any authority beyond the specific matters set forth in this Section 4.1.4, and in particular shall not have any power to amend or modify the terms of this Agreement, or any authority with respect to amendments to
the Research and Development Plan after the Research Term, which amendments to the Research and Development Plan shall be determined solely by EISAI, subject to reasonable consideration of EPIZYME’s comments and input with respect thereto. In
any case where a matter within the JSC’s authority arises, the JSC shall convene a meeting and consider such matter within [**] days after the matter is first brought to the JSC’s attention, or, if earlier, at the next regularly-scheduled
JSC meeting. 
 4.1.5 Decisions. Except as otherwise provided herein, all decisions of the JSC shall be made by
consensus, with each Party collectively having one vote. The Parties shall use good faith, reasonable efforts to attempt to reach consensus on each matter submitted to the JSC. If the JSC cannot agree on a matter within the JSC’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, any
dispute regarding whether or not a Compound has satisfied the applicable Lead Candidate Criteria or Development Candidate Selection Criteria, or whether Proof of Concept has been achieved, as applicable, shall be resolved by referring the matter to
a mutually-acceptable Third Party Technical Expert for a binding determination on the matter. “Third Party Technical Expert” shall mean a Third Party expert acceptable to and approved in writing in advance by both Parties with the
relevant technical expertise in pharmaceutical research and development; provided that if the Parties are not able to agree on a mutually acceptable Third Party Technical Expert within [**] days after the Executive Officers fail to
resolve the matter, the Third Party Technical Expert shall be appointed by the New York, New York office of the AAA. For purposes of clarity, any dispute regarding a matter within the JSC’s authority shall, if not resolved by escalation to the
respective Executive Officers of the Parties or by the Third Party Technical Expert, as applicable, be deadlocked until resolved by the mutual agreement of the Parties or by unanimous JSC consensus. Notwithstanding the foregoing provisions of this
Section 4.1.5, neither Party shall unreasonably withhold, condition or delay its agreement as to any matter if such withholding, conditioning or delay would be inconsistent with such Party’s obligations to use Commercially Reasonable
Efforts to Develop and Commercialize Therapeutic Products under this Agreement. 

  
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 4.1.6 Subcommittee(s). From time to time, the JSC 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 JSC determines is appropriate from time to time. Such members
shall be individuals with expertise and responsibilities in the relevant areas such as non-clinical Development, pharmacology, clinical Development, Patents, process sciences, Manufacturing, quality and regulatory affairs, as applicable to the stage
of the project or activity. 
 4.2 Alliance Managers. Promptly after the Effective Date, each Party shall appoint an
individual to act as alliance manager for such Party (each, an “Alliance Manager”). 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. The Alliance Managers shall attend all meetings of the JSC and shall be responsible for assisting the JSC 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 EISAI, in their sole discretion, from time to time, shall be promptly provided to the other Party in accordance with Section 14.7. 

4.3 Senior Management Meetings. Without limiting the generality of the foregoing in this Article 4, the senior management of each
Party, including, for EPIZYME, the Chief Executive Officer, Chief Scientific Officer, Chief Business Officer, and Chief Medical Officer, and, for EISAI, the President of the Oncology Product Creation Unit and other appropriate members of senior
management of EISAI as may be designated by EISAI, shall meet in person [**] a year, at a time and location to be mutually agreed by the Parties, to discuss the Collaboration, strategic plans for Licensed Products, and other related matters.

 ARTICLE 5 
 LICENSE GRANTS 
 5.1 License Grant To EISAI. Subject to the terms
and conditions of this Agreement: 
 5.1.1 Compounds, Licensed Compounds and Licensed Products. EPIZYME hereby grants to
EISAI (a) an exclusive right and license (even as to EPIZYME and its Affiliates) in the Field in the Territory, with the right to grant sublicenses (subject to Section 5.1.2), under the EPIZYME IP, EPIZYME Collaboration IP, and
EPIZYME’s interest in the Joint IP, to Develop, Manufacture, have Manufactured, use, offer for sale, sell, import and otherwise Commercialize Licensed Compounds and Licensed Products, and (b) a non-exclusive right and license in the Field
in the Territory, with the right to grant sublicenses (subject to Section 5.1.2), under the EPIZYME IP, EPIZYME Collaboration IP, and EPIZYME’s interest in the Joint IP, to Develop Compounds as necessary to exercise the rights granted in
the foregoing clause (a). 
 5.1.2 EISAI’s Sublicensing Rights. EISAI shall have the right to grant sublicenses
under the rights granted to it under Section 5.1.1 without the prior written consent of EPIZYME, to (a) any EISAI Affiliate, or (b) any Third Party; provided, however, that until the earlier of (i) the date
that EPIZYME has notified EISAI of its decision to not exercise the Profit-Sharing Option with respect to a particular Licensed Compound, and (ii) the date that the Profit-

  
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Sharing Option with respect to the applicable Licensed Compound expires unexercised pursuant to Section 6.1.4, EISAI shall not have the right to grant sublicenses under Section 5.1.1 to
any Third Party with respect to such Licensed Compound, any Therapeutic Product or Veterinary Product comprising such Licensed Compound or any related Diagnostic Product to any Third Party to Develop or Commercialize such Licensed Compound or
Licensed Products specifically for the U.S., without the prior written consent of EPIZYME, other than (A) sublicenses granted to Third Party service providers engaged by EISAI in the ordinary course of business and (B) sublicenses granted
pursuant to Section 9.5.5 with respect to such Licensed Compounds, Therapeutic Product, Veterinary Product or Diagnostic Product; and provided further that, if EPIZYME exercises the Profit-Sharing Option with respect to a
particular Licensed Compound, the Parties shall mutually agree upon any sublicenses granted by either Party to any Third Party with respect to the Development or Commercialization of any resulting Shared Product in accordance with the applicable
Joint Development and Commercialization Agreement, other than (1) sublicenses granted to Third Party service providers engaged by EISAI in the ordinary course of business and (2) sublicenses granted pursuant to Section 9.5.5 with
respect to such Shared Product. EISAI shall provide EPIZYME with a fully-executed copy of any agreement (redacted as necessary to protect confidential or commercially sensitive information) reflecting any sublicense granted by EISAI under this
Section 5.1.2, other than sublicenses to Affiliates or Third Party service providers engaged by EISAI in the ordinary course of business, promptly (but in no event later than [**] days) after the execution thereof. Each sublicense granted by
EISAI under this Section 5.1.2 shall be subject to and consistent with the terms and conditions of this Agreement, including Section 5.2. EISAI 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 5.1.2. 
 5.2 Compliance with UNC License
Agreement. 
 5.2.1 UNC Rights. The license grants by EPIZYME to EISAI set forth in Section 5.1.1 include the
sublicense of certain rights licensed to EPIZYME under the UNC License Agreement. EISAI’s rights and licenses under, or with respect to, such sublicense rights are limited to the rights granted by UNC to EPIZYME under the UNC License
Agreement and are subject to all applicable restrictions, limitations and obligations imposed on EPIZYME or its sublicensees in the UNC License Agreement. EISAI shall comply, and cause its Affiliates and Sublicensees to comply, with all such
restrictions, limitations and obligations (including Articles 6 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 License Agreement). 

5.2.2 Further Sublicenses. Any obligations required by the UNC License Agreement to be included in a sublicense thereunder, shall
be deemed to be included in this Agreement and shall be further included by EISAI in any sublicense granted by EISAI under this Agreement. 
 5.2.3 Disclaimer and Limitation of Warranty. EISAI (and any Sublicensee of EISAI) specifically acknowledges the disclaimer of warranty and limitation on UNC’s liability, as provided in Article
10 of the UNC License Agreement. 

  
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 5.2.4 U.S. Manufacture. It is agreed that any Licensed Product that is Covered by a
UNC Patent that is used or sold in the United States shall be Manufactured in accordance with 35 U.S.C. § 204. 
 5.2.5
U.S. Government Rights. The license granted by EPIZYME in Section 5.1.1 with respect to the rights licensed under the UNC License Agreement are limited by and subject to the rights and requirements of the United States government as set
forth in the UNC License Agreement. 
 5.3 License Grants to EPIZYME. Subject to the terms and conditions of this
Agreement: 
 5.3.1 Performance of Obligations. EISAI hereby grants to EPIZYME a non-exclusive royalty-free license in the
Field in the Territory, with the right to grant sublicenses (subject to Section 5.3.2), under the EISAI IP, EISAI Collaboration IP, EISAI’s interest in the Joint IP and EISAI’s licenses under the EPIZYME IP, EPIZYME Collaboration IP,
and EPIZYME’s interest in the Joint IP, solely to perform EPIZYME’s obligations under and in accordance with the Research and Development Plan. 
 5.3.2 EPIZYME’s Sublicensing Rights. EPIZYME may grant sublicenses under the rights granted to it under Section 5.3.1 without the prior written consent of EISAI to (a) any of
EPIZYME’s Affiliates, and (b) Third Party service providers engaged by EPIZYME in the ordinary course of business (for example and without limitation, to synthesize Compounds). Each sublicense granted by EPIZYME under this
Section 5.3.2 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 5.3.2. 
 5.4 Rights Retained by the Parties. 

5.4.1 Any rights of EPIZYME or EISAI, as the case may be, not expressly granted to the other Party pursuant to this Agreement shall be
retained by such Party. 
 5.4.2 For clarity, subject to Section 8.1 and Section 8.2: 

(a) EPIZYME retains the right, under Patents and Know-How Controlled by EPIZYME, including its interest in Joint IP, to perform ongoing
platform discovery activities; 
 (b) EPIZYME retains the right, under Patents and Know-How Controlled by EPIZYME, including
its interest in Joint IP, to Develop, Manufacture and Commercialize biomarkers and diagnostic assays and tests outside of this Agreement, subject to the license granted to EISAI under Section 5.1.1; and 

(c) EISAI retains the right, under Patents and Know-How Controlled by EISAI, including its interest in Joint IP, to Develop, Manufacture
and Commercialize biomarkers and diagnostic assays and tests outside of this Agreement. 

  
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 5.5 Section 365(n) of the Bankruptcy Code. All rights and licenses granted under
or pursuant to this Agreement by EISAI or EPIZYME are, and shall otherwise be deemed to be, for purposes of Section 365(n) of the U.S. Bankruptcy Code or any analogous provisions in any other country or jurisdiction, licenses of right to
“intellectual property” as defined under Section 101 of the U.S. Bankruptcy Code. The Parties agree that the Parties, as licensees of such rights under this Agreement, shall retain and may fully exercise all of their respective rights
and elections under the U.S. Bankruptcy Code or any analogous provisions in any other country or jurisdiction. The Parties further agree that, in the event of the commencement of a bankruptcy proceeding by or against either Party under the U.S.
Bankruptcy Code or any analogous provisions in any other country or jurisdiction, the Party hereto that is not a party to such proceeding shall be entitled to a complete duplicate of (or complete access to, as appropriate) any such intellectual
property and all embodiments of such intellectual property, which, if not already in the non-subject Party’s possession, shall be promptly delivered to it (a) upon any such commencement of a bankruptcy proceeding upon the non-subject
Party’s written request therefor, unless the Party subject to such proceeding elects to continue to perform all of its obligations under this Agreement, or (b) if not delivered under clause (a) above, following the rejection of this
Agreement by or on behalf of the Party subject to such proceeding upon written request therefor by the non-subject Party. 
 5.6
Access to Know-How. 
 5.6.1 To the extent not already provided prior to the Effective Date, EPIZYME promptly shall
provide to EISAI 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 EISAI as necessary or reasonably useful to exercise its rights under the
license grants in Section 5.1.1 in order to undertake activities assigned to EISAI under the Research and Development Plan. In addition, (a) in the event that EPIZYME does not perform any activities assigned to it under the Research and
Development Plan, EPIZYME promptly shall provide to EISAI 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 EISAI as necessary or reasonably
useful to exercise its rights under the license grants in Section 5.1.1 in order to undertake activities assigned to, but not performed by, EPIZYME under the Research and Development Plan and (b) during the [**] months following the end of
the Research Term, to the extent not already provided prior to the end of the Research Term, EPIZYME promptly shall provide to EISAI 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 EISAI as necessary or reasonably useful to exercise its rights under the license grants in Section 5.1.1. Notwithstanding the foregoing or anything else to the contrary in this Section 5.6,
unless otherwise agreed by the Parties EPIZYME shall not be obligated to undertake any transfer of Know-How or provide any technical assistance to EISAI beyond [**] months following the end of the Research Term. 

5.6.2 In furtherance of, and subject to, the foregoing and without expanding the scope of the licenses granted to EISAI pursuant to
Section 5.1.1, from time to time, until [**] months following the end of the Research Term, as shall be reasonably requested by EISAI, EPIZYME shall: 
 (a) make reasonably available to EISAI then existing documentation Controlled by EPIZYME constituting material support, performance advice, shop practice, standard operating procedures, specifications as
to materials to be used and control methods that are necessary or reasonably useful to use and practice the EPIZYME IP; and 

  
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 (b) cause appropriate employees and representatives of EPIZYME and its Affiliates to meet
with employees or representatives of EISAI at both the facility of EPIZYME and the designated facility of EISAI, at mutually convenient times, to provide reasonable technical assistance to EISAI with respect to the use and practice of the EPIZYME
IP. 
 ARTICLE 6 
 EPIZYME PROFIT-SHARING OPTION; JOINT DEVELOPMENT AND 
 COMMERCIALIZATION
AGREEMENT 
 6.1 Epizyme Profit-Sharing Option. 

6.1.1 Profit-Sharing Option. On a Licensed Compound-by-Licensed Compound basis, at any time during the Option Exercise Period,
subject to Section 8.2.1(c), EPIZYME shall have the right (the “Profit-Sharing Option”), in accordance with this Section 6.1, to elect to jointly Develop and Commercialize with EISAI (or an Affiliate designated by EISAI)
such Licensed Compound, any Therapeutic Product or Veterinary Product comprising such Licensed Compound and any related Diagnostic Product(s), in the Field for the United States, which right EPIZYME may exercise in accordance with
Section 6.1.3. Following any such exercise, EPIZYME and EISAI (or an Affiliate designated by EISAI) shall negotiate in good faith terms and conditions to be set forth in an agreement, which agreement shall include appropriate plans and budgets,
for such joint Development and Commercialization activities (including Manufacturing plans and supply forecasts) with respect to such Shared Product (or provisions for establishing such plans) and shall be based on (a) terms and conditions that
are substantially the same as those set forth in Section 6.2, Article 9 and Exhibit E and (b) such other reasonable and customary provisions for transactions of this type as the Parties may agree (such agreement, the “Joint
Development and Commercialization Agreement”). Notwithstanding the foregoing, unless and until the Parties enter into a definitive Joint Development and Commercialization Agreement with respect to the applicable Shared Product, the
provisions of Section 6.2, Article 9 and Exhibit E, as such terms may be modified by mutual written agreement of the Parties, shall apply and shall be deemed to be the Joint Development and Commercialization Agreement with respect to the
applicable Shared Product. 
 6.1.2 Access to Information Regarding Licensed Products. On a Licensed Compound-by-Licensed
Compound basis, to the extent that EPIZYME has not exercised the Profit-Sharing Option with respect to such Licensed Compound pursuant to Section 6.1.3 prior to achievement of Proof of Concept for such Licensed Compound, EISAI shall provide
EPIZYME, promptly following the determination by the JSC that achievement of Proof of Concept has occurred for a Licensed Compound, with (a) information on all Out-of-Pocket Costs incurred by EISAI through achievement of Proof of Concept, and
(b) regulatory information submitted to the FDA prior to the applicable time period mentioned above. In addition, EPIZYME may, by written notice to EISAI, request such additional information as EPIZYME reasonably believes may be material to its
decision as to whether to exercise the Profit-Sharing Option within [**] 

  
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days after receiving the information from EISAI pursuant to this Section 6.1.2. EISAI shall provide such additional information as promptly as practicable after receipt of EPIZYME’s
written request for such information. 
 6.1.3 Exercise of Profit-Sharing Option. On a Licensed Compound-by-Licensed
Compound basis, if EPIZYME elects to exercise its Profit-Sharing Option on a Licensed Compound, then in order to exercise such Profit-Sharing Option, EPIZYME shall provide to EISAI written notice that it is exercising such Profit-Sharing Option
(“Notice of Exercise”) at any time during the period commencing on the Effective Date and continuing until the date that is [**] days after EPIZYME has received all information regarding such Licensed Compound, any Therapeutic
Product or Veterinary Product comprising such Licensed Compound and any related Diagnostic Product(s) EISAI is required to deliver to EPIZYME pursuant to Section 6.1.2 (such period, the “Option Exercise Period”). 

6.1.4 Expiration of Profit-Sharing Option. On a Licensed Compound-by-Licensed Compound basis, failure by EPIZYME to provide its
Notice of Exercise within the applicable Option Exercise Period as set forth in Section 6.1.3 above shall result in the expiration of the applicable Profit-Sharing Option with respect to the applicable Licensed Compound, in which event EPIZYME
shall have no right to jointly Develop and Commercialize with EISAI (or an Affiliate designated by EISAI) such Licensed Compound, any Therapeutic Product or Veterinary Product comprising such Licensed Compound and any related Diagnostic Product(s),
in the Field for the United States. 
 6.2 Effects of Exercising Profit-Sharing Option. On a Licensed
Compound-by-Licensed Compound basis, if EPIZYME exercises the Profit-Sharing Option with respect to a Licensed Compound, then, commencing upon such date of exercise by EPIZYME and during the remainder of the applicable Profit-Share Term: 

(a) such Licensed Compound, any Therapeutic Product or Veterinary Product comprising such Licensed Compound, and any related Diagnostic
Product(s) shall be deemed a “Shared Product”; 
 (b) EISAI shall grant EPIZYME an exclusive license under the
EISAI IP, EISAI Collaboration IP, EISAI’s interest in the Joint IP and EISAI’s licenses under the EPIZYME IP, EPIZYME Collaboration IP, and EPIZYME’s interest in the Joint IP, as necessary to perform EPIZYME’s obligations under
and in accordance with the applicable Joint Development and Commercialization Agreement; 
 (c) without limiting the generality
of EISAI’s rights or obligations hereunder to Develop and Commercialize such Shared Product outside of the United States, EPIZYME and EISAI shall jointly Develop and Commercialize such Shared Product for the United States during the
Profit-Share Term in accordance with the applicable Joint Development and Commercialization Agreement; 
 (d) each Party shall
use Commercially Reasonable Efforts to Develop and Commercialize such Shared Product(s) for the United States during the Profit-Share Term in accordance with the applicable Joint Development and Commercialization Agreement. For

  
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purposes of clarity, for so long as EISAI is in compliance with this Section 6.2(d), EISAI shall be deemed to meet its diligence obligation under Section 3.2 to Develop and
Commercialize at least one (1) Therapeutic Product in the United States; provided, however, that nothing in this Section 6.2(d) shall be construed as a limitation of EISAI’s diligence obligations under
Section 3.2 with respect to Japan or any of the Major EU Countries; 
 (e) EISAI’s obligation to pay the royalties
set forth in Section 7.5.1(a) and, to the extent applicable, Section 7.12 with respect to Net Sales of such Shared Product in the United States shall terminate; 
 (f) the Parties shall share the Net Profits/Losses with respect to such Shared Product as set forth in Section 7.6; 
 (g) EPIZYME shall reimburse EISAI for twenty-five percent (25%) of Past Development Costs, as provided in Section 7.2.3; 

(h) the Parties shall agree upon a Joint Development Plan Development of such Shared Product for the United States, and each Party shall
be responsible for fifty percent (50%) of all Shared Development Costs (as defined on Exhibit E); 
 (i) subject to
Section 7.3.5, all milestone payments that become payable by EISAI pursuant to Section 7.3.1 after such date of exercise of the applicable Profit-Sharing Option by EPIZYME shall be reduced by fifty percent (50%) (it being understood
that the consequences set forth in this clause (i) shall apply only once upon the first occurrence of EPIZYME’s exercise of the Profit-Sharing Option); 
 (j) subject to Section 7.4.3, (i) all sales milestone payments that become payable by EISAI pursuant to Section 7.4.1 after such date of exercise of the applicable Profit-Sharing Option by
EPIZYME shall be reduced by fifty percent (50%) and the Net Sales dollar threshold for each sales milestone event set forth in Section 7.4 shall be reduced to fifty percent (50%) of the amount set forth in Section 7.4.1 (it being
understood that the consequences set forth in this subsection (j)(i) shall apply only once upon the first occurrence of EPIZYME’s exercise of the Profit-Sharing Option), and (ii) Net Sales of the applicable Shared Product in the ROW, but
not in the U.S., only shall be counted in determining whether the applicable Net Sales dollar thresholds in Section 7.4.1 have been achieved; and 
 (k) For the avoidance of doubt, the royalties set forth in Section 7.5 and, to the extent applicable, Section 7.12 with respect to any Licensed Product for which EPIZYME does not exercise the
Profit-Sharing Option, and with respect to any Shared Product in the ROW, shall remain payable as set forth therein. 
 6.3
Additional Past Development Costs. Promptly after EPIZYME’s exercise of the Profit-Sharing Option with respect to a Licensed Compound, EISAI shall provide EPIZYME with information on all Out-of-Pocket Costs incurred by EISAI prior to
EPIZYME’s exercise of such Profit-Sharing Option to the extent such information was not already provided to EPIZYME under Section 2.4 or Section 6.1.2 above. 

  
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 ARTICLE 7 
 FINANCIAL TERMS 
 7.1 Upfront Fee. In partial consideration for the
licenses granted to EISAI hereunder, EISAI shall pay EPIZYME a non-creditable payment of Three Million Dollars ($3,000,000) within [**] Business Days after the Effective Date. 
 7.2 Research Funding. 
 7.2.1 Research and Development Plan Funding.
EISAI shall pay to EPIZYME the Development Costs incurred by EPIZYME in performing activities pursuant to the Research and Development Plan pursuant to Section 7.2.2, provided however that, if EPIZYME exercises the
Profit-Sharing Option with respect to a Shared Product, then, following the date of such exercise by EPIZYME, subsequent Shared Development Costs incurred with respect to such Shared Product shall be taken into account in determining Net
Profits/Losses in accordance with the applicable Joint Development and Commercialization Agreement. For purposes of clarity, except as otherwise provided in Section 7.2.3, EISAI shall be solely responsible for any and all Development Costs
incurred by EISAI or its Affiliates in performing activities pursuant to the Research and Development Plan. 
 7.2.2 Annual
Budgets; Payment and Reconciliation of Development Costs. 
 (a) Within no later than [**] days prior to April 1, 2012
and each anniversary of April 1 thereafter, on a Licensed Product-by-Licensed Product basis, subject to Section 2.2.1(b), the Parties (acting through the JSC) shall mutually agree to an appropriate budget (or an appropriate amendment or
update to the then-current budget) under the Research and Development Plan to cover Development Costs, including FTE Costs and Out-of-Pocket Costs, expected to be incurred by EPIZYME in the performance of Development activities under the Research
and Development Plan during the upcoming Budget Year (or pro rata portion thereof, as applicable) during the Research Term, provided that for each Budget Year (or pro rata portion thereof, as applicable) during the Research Term, the
Research and Development Plan shall provide for, and the Development budget shall cover, on average a minimum of [**] EPIZYME FTEs unless the Parties (acting through the JSC) otherwise mutually agree; provided further 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 Development Costs expected to be incurred until the anticipated completion of such Clinical
Trial(s) or other material Development activities (collectively, the “Budgeted Costs”). For purposes of clarity, the initial budget (which covers certain Budgeted Costs from the Effective Date through July 31, 2013) is set
forth in the initial Research and Development Plan attached hereto as Exhibit D, and shall remain in effect until amended or updated by mutual agreement of the Parties (acting through the JSC) pursuant to this Section 7.2.2(a).

 (b) Each Party shall calculate and maintain records of Development Costs incurred by it in accordance with procedures to be
established by the JSC. 
 (c) Within [**] days following the end of each Calendar Quarter during the Research Term, EPIZYME
shall provide to EISAI a report of actual Development Costs, 

  
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including FTE Costs and Out-of-Pocket Costs, incurred by EPIZYME during such Calendar Quarter in accordance with the Research and Development Plan in a manner that allocates such Development
Costs to the extent possible to a specific activity in the applicable budget, together with the evidence supporting such Development Costs. 
 (d) EPIZYME promptly shall inform the JSC upon EPIZYME’s determining that it is likely to overspend the Budgeted Costs for any Budget Year during the Research Term with respect to any Development
activities assigned to it in the Research and Development Plan (such overspend, a “Cost Overrun”) and the JSC shall promptly hold an an-hoc meeting and shall discuss reasonably and in good faith what steps to take to address the
Cost Overrun (which may include modifying the Research and Development Plan to reduce the costs appropriately or increasing the Budgeted Costs for such Development activity so that there is no longer a Cost Overrun). 

(e) Not later than [**] Business Days after receipt of each quarterly report provided by EPIZYME pursuant to Section 7.2.2(c),
EISAI shall pay EPIZYME an amount equal to the Development Costs set forth in such report; provided that EISAI shall have no obligation to pay EPIZYME for any Cost Overrun in excess of [**] percent ([**]%) of the aggregate Budgeted
Costs for any Budget Year (an “Excess Overrun”), and EPIZYME solely shall bear all such Excess Overruns. Notwithstanding any of the foregoing in this Section 7.2.2 to the contrary, EPIZYME shall not be required to conduct
Development activities in any Calendar Quarter that would require EPIZYME to incur any Excess Overruns. 
 7.2.3
EPIZYME’s Reimbursement of Past Development Costs Following Exercise of EPIZYME Profit-Sharing Option. If EPIZYME exercises the Profit-Sharing Option with respect to a Licensed Compound, on a Shared Product-by-Shared Product basis, EISAI
shall be entitled to fully credit an amount equal to twenty-five percent (25%) of (a) all Development Costs incurred by EPIZYME under the Research and Development Plan with respect to the Development of such Shared Product and paid for by
EISAI pursuant to Sections 7.2.1 and 7.2.2, and (b) all Out-of-Pocket Costs incurred by EISAI under the Research and Development Plan with respect to the Development of such Shared Product through the date of EPIZYME’s exercise of the
applicable Profit-Sharing Option, but excluding internal EISAI costs and expenses of the kinds that are normally included in full-time equivalent rates for internal personnel, in each case identified by EISAI under Section 2.4,
Section 6.1.2 or Section 6.3 (such Development Costs in clauses (a) and (b) shall be referred to herein, collectively, as the “Past Development Costs”, and EPIZYME’s twenty-five percent (25%) share of
such Past Development Costs shall be referred to herein as “EPIZYME’s Reimbursement Amount”), against any future milestone payments payable by EISAI to EPIZYME pursuant to Section 7.3 or Section 7.4 or royalties
payable by EISAI to EPIZYME pursuant to Section 7.5.1; provided that all such credits under this Section 7.2.3 shall not reduce the milestone payments payable to EPIZYME under Section 7.3 or Section 7.4 or royalties
payable to EPIZYME under Section 7.5.1 to less than fifty percent (50%) of the milestone payments otherwise due to EPIZYME pursuant to Section 7.3 or Section 7.4 (as adjusted pursuant to Section 6.2(i) or 6.2(j), as
applicable) or royalties otherwise due to EPIZYME pursuant to Section 7.5.1 (as adjusted pursuant to Section 6.2(e)); provided, further, that EISAI shall have the right to carry forward for application against any
subsequent milestone payments payable to EPIZYME under Section 7.3 or Section 7.4 or any subsequent royalties payable to EPIZYME under Section 7.5.1, as 

  
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applicable, any remaining amount of EPIZYME’s Reimbursement Amount that are not so credited due to the limitation in the immediately preceding proviso. In the event that this Agreement is
terminated by EISAI pursuant to Section 13.3.1 as a result of EPIZYME’s uncured material breach prior to the time that all of EPIZYME’s Reimbursement Amount has been credited by EISAI pursuant to this Section 7.2.3, then not
later than [**] Business Days after the date of termination pursuant to Section 13.3.1 EPIZYME shall pay to EISAI any remaining amount of EPIZYME’s Reimbursement Amount not so credited. 

7.3 Development Milestones. 
 7.3.1 Subject to Section 6.2(i), EISAI shall make the non-creditable milestone payments to EPIZYME that are set forth below in accordance with Sections 7.3.3 and 7.3.4 upon the first occurrence of
the milestone events set forth below. 
  

					
	 Milestone Event
	  	Milestone
Payments
(in $
[**])	 
	 (1) Upon the selection by the JSC of a Lead Candidate.
	  	 	3	  
	 (2) Earlier of (a) achievement of the Development Candidate Selection Criteria or (b) commencement of a GLP Toxicology Study for
a Lead Candidate by EPIZYME (in accordance with the terms hereof) or by EISAI, its Affiliates or Sublicensees.
	  	 	4	  
	 (3) Initiation by EISAI, its Affiliates or Sublicensees of Phase 1 Clinical Trial of a Development Candidate.
	  	 	6	  
	 [**]
	  	 	[**]	  
	 [**]
	  	 	[**]	  
	 [**]
	  	 	[**]	  
	 [**]
	  	 	[**]	  

 Except as otherwise set forth in Section 7.3.5 below, no milestone payment in this Section 7.3.1 will be made
more than once irrespective of the number of Compounds or Licensed Products that have achieved the milestone events set forth in this Section 7.3.1. The maximum aggregate amount payable by EISAI pursuant to this Section 7.3.1 is
$93,000,000. 
 7.3.2 If, upon achievement of a particular milestone event set forth in the table in Section 7.3.1, any of
the applicable previous milestone payments for milestone events 1 through 6 above set forth in the table in Section 7.3.1 has not been paid, then such milestone payment(s) shall be payable concurrently with the payment for such subsequent
achievement. 

  
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 7.3.3 Notwithstanding anything in this Agreement to the contrary, the Parties agree that
milestone event 1 has been achieved as of the Effective Date, and EISAI shall pay EPIZYME the corresponding milestone payment on or before [**]. 
 7.3.4 Upon achievement by EPIZYME of milestone event 2, if applicable, EPIZYME shall promptly notify EISAI of such achievement, and EISAI shall pay EPIZYME the corresponding milestone payment within [**]
days after receipt of an invoice for the milestone payment from EPIZYME (which invoice shall not be sent by EPIZYME prior to achievement of such milestone event). Upon achievement by or on behalf of EISAI, its Affiliates or Sublicensees of a
milestone event, other than milestone event 1 or milestone event 2, EISAI shall promptly (but in no event more than [**] Business Days after achievement thereof) notify EPIZYME of such achievement, and EISAI shall pay EPIZYME the corresponding
milestone payment within [**] days after receipt of an invoice for the milestone payment from EPIZYME (which invoice shall not be sent by EPIZYME before receipt of such notification from EISAI). 

7.3.5 Notwithstanding anything in Section 6.2(i) or this Section 7.3 to the contrary, if any milestone event set forth in the
table in Section 7.3.1 is achieved solely with respect to a Shared Product and, in accordance with Section 6.2(i), only fifty percent (50%) of the corresponding milestone payment amount is paid or payable by EISAI to EPIZYME under
Section 7.3.1, and the same milestone event is subsequently achieved solely with respect to a Licensed Product that is not a Shared Product, then, in addition to the adjusted milestone payment amount which was paid or payable by EISAI to
EPIZYME in accordance with Section 6.2(i) with respect to such Shared Product, EISAI shall pay EPIZYME the balance of the corresponding milestone payment which would have been payable to EPIZYME had the adjustment in Section 6.2(i) not
been made. For purposes of illustration only, if a Phase I Clinical Trial is Initiated for a Shared Product, EISAI shall pay EPIZYME a milestone payment of $3M taking into account the adjustment in Section 6.2(i). If another Phase I Clinical
Trial is subsequently Initiated for a Licensed Product that is not a Shared Product, then EISAI shall pay EPIZYME an additional $3M (which is the balance of the $6M milestone payment which would have been payable to EPIZYME under Section 7.3.1
had the milestone payment amount adjustment in Section 6.2(i) not been made). 
 7.4 Sales Milestones. 

7.4.1 Subject to Section 6.2(j), as to each of the sales milestone events set forth below, EISAI shall pay EPIZYME non-creditable
sales milestone payments indicated below upon the first achievement by EISAI, its Affiliates or Sublicensees of the success milestone events set forth below. 
  

					
	 Sales Milestone Event

(For All Licensed Products)
	  	Milestone
Payment
(in $
[**])	 
	 First Calendar Year in which aggregate world-wide Net Sales of Licensed Product(s) are greater than or equal to
$[**]
	  	 	[**]	  
	 First Calendar Year in which aggregate world-wide Net Sales of Licensed Product(s) are greater than or equal to
$[**]
	  	 	[**]	  
	 First Calendar Year in which aggregate world-wide Net Sales of Licensed Product(s) are greater than or equal to
$[**]
	  	 	[**]	  

  
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 Except as otherwise set forth in Section 7.4.3 below, no milestone payment in this
Section 7.4.1 will be made more than once irrespective of the number of Calendar Years in which the sales milestone events set forth in this Section 7.4.1 are achieved. The maximum aggregate amount payable by EISAI pursuant to this
Section 7.4.1 is $115,000,000. 
 7.4.2 As to each of the foregoing sales milestones, upon achievement thereof by EISAI,
its Affiliates or Sublicensees, EISAI shall promptly (but in no event later than the date on which the royalty report for the Calendar Quarter in which such achievement occurs is due pursuant to Section 7.7.1) notify EPIZYME of such
achievement, and EISAI shall pay EPIZYME the corresponding sales milestone payment on or before the date on which royalties for the Calendar Quarter in which such achievement occurs are due pursuant to Section 7.7.3. For the avoidance of doubt,
more than one of the foregoing sales milestone payments may be earned and become payable with respect to Licensed Products in the same Calendar Year based on aggregate world-wide Net Sales of Licensed Product(s) during such Calendar Year.

 7.4.3 Notwithstanding anything in Section 6.2(j) or this Section 7.4 to the contrary, if any milestone event set
forth in the table in Section 7.4.1 is achieved and, in accordance with Section 6.2(j), only fifty percent (50%) of the corresponding milestone payment amount, based on sales thresholds as adjusted in accordance with
Section 6.2(j), is paid or payable by EISAI to EPIZYME under Section 7.4.1, and the same milestone event, disregarding adjustments to the sales thresholds in accordance with Section 6.2(j), is subsequently achieved solely with respect
to Licensed Product(s) that are not Shared Product(s), then, in addition to the adjusted milestone payment amount which was paid or payable by EISAI to EPIZYME in accordance with Section 6.2(j), EISAI shall pay EPIZYME the balance of the
corresponding milestone payment which would have been payable to EPIZYME had the adjustments in Section 6.2(j) not been made. For purposes of illustration only, if Net Sales of a Shared Product in a Calendar Year (for clarity, excluding, as set
forth in Section 6.2(j), Net Sales of the Shared Product in the United States) reach $[**], EISAI shall pay EPIZYME a milestone payment of $[**] in accordance with Section 6.2(j). If Net Sales of Licensed Product(s) that are not Shared
Product(s) in any subsequent Calendar Year reach $[**], then EISAI shall pay EPIZYME an additional $[**] (which is the balance of the $[**] milestone payment which would have been payable to EPIZYME under Section 7.4.1 had the adjustments in
Section 6.2(j) not been made). 
 7.5 Licensed Product Royalties. 

7.5.1 Licensed Product Royalties. 
 (a) U.S. Royalties. Subject to Sections 6.2(e), 7.5.2, 7.5.3, and 7.5.4, EISAI shall pay EPIZYME incremental royalties on Annual Net Sales of each Therapeutic Product in the U.S. during the Royalty
Term for such Therapeutic Product in the U.S., on a Therapeutic Product-by-Therapeutic Product basis, at the royalty rates set forth in the table below: 
  

					
	 U.S. Annual Net Sales

(For Each Therapeutic Product)
	  	Incremental
Royalty Rates	 
	 Portion up to and including $[**]
	  	 	[**]	 % 
	 Portion greater than $[**] up to and including $[**]
	  	 	[**]	 % 
	 Portion greater than $[**]
	  	 	[**]	 % 

  
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 For example, if U.S. Annual Net Sales of a Therapeutic Product were $[**], the royalties payable with
respect to such U.S. Annual Net Sales, subject to adjustment as set forth in this Section 7.5 below, would be [**]. 
 For clarity, the
royalty tiers set forth in the table above shall apply separately to each separate Therapeutic Product. For example, if U.S. Annual Net Sales for Therapeutic Product A during a Calendar Year are $[**], and U.S. Annual Net Sales for Therapeutic
Product B during such Calendar Year are $[**], then all such U.S. Annual Net Sales for both Therapeutic Product A and Therapeutic Product B during such Calendar Year shall bear a royalty rate of [**]%. 

(b) ROW Royalties. Subject to Sections 7.5.2, 7.5.3, and 7.5.4, EISAI shall pay EPIZYME royalties of [**] percent ([**]%) on
Annual Net Sales of each Therapeutic Product in each country in the ROW during the Royalty Term for such Therapeutic Product in such country, on a Therapeutic Product-by-Therapeutic Product basis. 

7.5.2 Royalty Term and Adjustments. 
 (a) EISAI’s royalty obligations to EPIZYME under Section 7.5.1 shall commence on a country-by-country and Licensed Product-by-Licensed Product basis on the date of First Commercial Sale by
EISAI, its Affiliates or Sublicensees 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”), as applicable: 
 (i) expiration of Patent-Based Exclusivity with respect to such Licensed Product in such
country; 
 (ii) expiration of Regulatory-Based Exclusivity with respect to such Licensed Product in such country; and

 (iii) the tenth (10th) anniversary of the First Commercial Sale of such Licensed Product in such country by EISAI, its
Affiliates or Sublicensees. 
 (b) The foregoing provisions of this Section 7.5 notwithstanding, the royalties payable
with respect to Net Sales of Licensed Products shall be reduced, on a Licensed Product-by-Licensed Product and country-by-country basis, to [**] percent ([**]%) of the amounts otherwise payable pursuant to Section 7.5.1 during any portion of
the Royalty Term when neither Patent-Based Exclusivity nor Regulatory-Based Exclusivity applies to such Licensed Product in such country. 

  
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 (c) With respect to each Licensed Product in the U.S., from and after the expiration of the
Royalty Term for such Licensed Product in the U.S., Net Sales of such Licensed Product in the U.S. shall be excluded for purposes of calculating the Net Sales thresholds and ceilings set forth in Section 7.5.1(a). 

(d) EISAI shall have no obligation to pay any royalty with respect to Net Sales of any Licensed Product in any country after the Royalty
Term for such Licensed Product in such country has expired. 
 7.5.3 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, (a) Comparable Third Party Product Competition is present with respect to such Licensed Product in such country
during such Calendar Quarter, or (b) a court or a governmental agency of competent jurisdiction requires EISAI or any of its Affiliates or Sublicensees to grant a compulsory license to a Third Party permitting such Third Party to make and sell
such Licensed Product in such country (such Licensed Product when sold by such Third Party, a “Compulsory Third Party Product”), and such Compulsory Third Party Product(s) have a market share of [**] percent ([**]%) or more of the
aggregate market in such country of the applicable Licensed Product and the Compulsory Third Party Product(s) collectively (based on sales of units of such Licensed Product and such Compulsory Third Party Product(s), as reported by IMS
International, or if such data are not available, such other reliable data source as reasonably determined by EPIZYME and EISAI (as used herein, a “unit” of a product means the equivalent amount of product used for an equivalent treatment
cycle of such product)), then, in each case (clause (a) or (b)), the royalties payable with respect to Net Sales of such Licensed Product pursuant to Sections 7.5.1 and 7.5.2 in such country during such Calendar Quarter shall be reduced to [**]
percent ([**]%) of the royalties otherwise payable pursuant to Sections 7.5.1 and 7.5.2. 
 7.5.4 Third Party Payments.

 (a) EISAI 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 all upfront payments, milestone payments, royalties, and other amounts paid by EISAI, its Affiliates or Sublicensees to Third Parties with respect to license rights to Third Party intellectual property
licensed by EISAI, its Affiliates or Sublicensees from the applicable Third Party that EISAI reasonably believes are necessary for the Development, Manufacture, or Commercialization of such Licensed Product in such country; provided,
however, that, to the extent that any such Third Party license includes a license to Third Party intellectual property that is applicable to products being or to be developed or commercialized by EISAI or its Affiliates other than such
Licensed Product in such country, then EISAI shall reasonably allocate all upfront payments, milestone payments and other non-royalty amounts between the Licensed Product and such other products, and EISAI shall only be entitled to credit against
the royalties due to EPIZYME hereunder upon Net Sales of such Licensed Product [**] percent ([**]%) of the amounts that are reasonably allocable to the Licensed Product. In addition, EISAI shall be entitled to credit against the royalties due to
EPIZYME hereunder defense costs in accordance with Section 9.4. 

  
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 (b) With respect to amounts payable to UNC with respect to a sublicense to EISAI under the
UNC License Agreement, EPIZYME and EISAI shall each bear [**] percent ([**]%) of the milestone amounts payable to UNC pursuant to Section 3.4 of the UNC License Agreement, and, as between EPIZYME and EISAI, EPIZYME shall be responsible for all
other amounts payable to UNC under the UNC License Agreement (including in the event that EPIZYME ceases to be a party to the UNC License Agreement and EISAI exercises its right to retain its sublicense under the UNC License Agreement pursuant to
Section 6.4 thereof). In the event EPIZYME enters into any other Third Party intellectual property license necessary for the Development, Manufacture, or Commercialization of a Licensed Product in a country after the Effective Date (EPIZYME
represents and warrants to EISAI that other than the UNC License Agreement, EPIZYME is not a party to any such relevant Third Party licenses as of the Effective Date), under which EPIZYME is entitled to grant a sublicense to EISAI, EISAI will have
the right to obtain such sublicense from EPIZYME; provided that, if EISAI elects to obtain such sublicense, EISAI shall pay one hundred percent (100%) of the amounts payable to the Third Party on account of such sublicense (either
directly to the Third Party licensor or to EPIZYME, as the Parties shall reasonably agree with the goal of ensuring timely payment to the Third Party) and EISAI shall be entitled to credit against the royalties due to EPIZYME upon Net Sales of such
Licensed Product in such country in an amount equal to [**] percent ([**]%) of the amounts paid by EISAI (either directly or indirectly through EPIZYME) to such Third Party with respect to such license rights for such Licensed Product in such
country. 
 (c) For purpose of clarity, (i) milestone amounts payable to UNC pursuant to Section 3.4 of the UNC
License Agreement, and (ii) all royalty, milestone and other payments to a Third Party (other than UNC) made by either Party under Third Party intellectual property licenses in accordance with this Section 7.5.4, in the case of both of the
foregoing clauses (i) and (ii), necessary for the Development, Manufacture, or Commercialization of a Shared Product in the United States, shall be deemed expenses which are taken into account in calculating Net Profits/Losses pursuant to
Exhibit E. 
 7.5.5 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 7.5.2(b), 7.5.3 and 7.5.4, on a country-by-country and Licensed Product-by-Licensed Product basis, reduce the effective royalties payable by
EISAI to EPIZYME pursuant to this Agreement for any Calendar Quarter below [**] percent ([**]%) of the otherwise applicable royalties pursuant to Section 7.5.1; provided that, EISAI 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 this Section 7.5.5. 

7.6 Profit Sharing. On a Shared Product-by-Shared Product basis, upon EPIZYME’s exercise of the Profit-Sharing Option for a
Shared Product pursuant to Section 6.1, during the Profit-Share Term for such Shared Product, the Parties shall share equally in Net Profits/Losses in accordance with the applicable Joint Development and Commercialization Agreement. Every
Calendar Quarter during the Profit-Share Term, in accordance with the applicable Joint 

  
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Development and Commercialization Agreement, EPIZYME and EISAI shall perform a reconciliation of Shared Development Costs, Cost of Goods, and Shared Commercialization Costs incurred by each Party
under such Joint Development and Commercialization Agreement. For purposes of clarity, except as may otherwise be provided in the applicable Joint Development and Commercialization Agreement, EISAI shall continue to be solely responsible for one
hundred percent (100%) of costs and expenses of Development and Commercialization of the Shared Product for the ROW. 
 7.7
Reports; Sales Milestones; Royalty Payments. 
 7.7.1 Until the expiration of EISAI’s royalty and sales milestone
payment obligations under this Article 7, EISAI shall make written reports to EPIZYME within [**] days after the end of each Calendar Quarter covering sales of Licensed Products on a product-by-product and country-by-country basis in the Territory
by EISAI, its Affiliates and Sublicensees during such Calendar Quarter. The information contained in each report under this Section 7.7 shall be considered Confidential Information of EISAI. 

7.7.2 Each such written report shall provide Net Sales by country by Licensed Product for the period in question, and all adjustments (if
any) made pursuant to Sections 7.5.2, 7.5.3 and 7.5.4. In addition to the foregoing, each such written report shall, with respect to each of the Major Market Countries, and, to the extent such information is available, with respect to other
countries, provide: 
 (a) number of units sold for each Licensed Product, as applicable; 

(b) the gross sales for each Licensed Product, as applicable; 
 (c) a calculation of the adjustments to Net Sales for Combination Products (if applicable); 
 (d) the calculation of the royalty payment due on such Net Sales pursuant to this Article 7; and 
 (e) the calculation of any sales milestone payments due to EPIZYME hereunder. 

7.7.3 Concurrently with the delivery of each such report, EISAI shall make the royalty payment and any sales milestone payments due to
EPIZYME under this Article 7 for the Calendar Quarter covered by such report. 
 7.7.4 For purposes of clarity, if EPIZYME
exercises its Profit-Sharing Option with respect to a Shared Product, the applicable Joint Development and Commercialization Agreement shall set forth the reporting, reconciliation and payment obligations of each Party in connection with Net
Profits/Losses with respect to such Shared Product. 
 7.8 Methods of Payments. All payments due from one Party (the
“Payor”) to the other Party (the “Payee”) under this Agreement or any Joint Development and Commercialization Agreement shall be paid in Dollars by electronic funds transfer to a bank account designated in writing
by the Payee. 

  
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 7.9 Accounting. 

7.9.1 Each Party 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 or the applicable Joint Development and Commercialization Agreement, setting forth (a) the sales and other disposition of Licensed Products sold or otherwise
disposed of in sufficient detail to enable royalties and sales milestones payable to EPIZYME under this Agreement to be determined, and to enable Net Profits/Losses shared between the Parties under the applicable Joint Development and
Commercialization Agreement to be determined, (b) the Development Costs incurred by such Party under this Agreement, and (c) Shared Development Costs, Cost of Goods, and Shared Commercialization Costs incurred by such Party under the
applicable Joint Development and Commercialization Agreement. 
 7.9.2 Each Party (the “audited Party”) 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, including Development Costs, Shared Development Costs,
Cost of Goods, and Shared Commercialization Costs, as applicable, to be examined by an independent accounting firm selected by the other Party (the “auditing Party”) and reasonably acceptable to the audited Party, for the purpose of
verifying reports provided by the audited Party under this Agreement or under the applicable Joint Development and Commercialization Agreement. Such audit shall not (i) be performed more frequently than [**]in any twelve (12)-month period
(unless a previous audit during such twelve (12)-month period revealed a material discrepancy with respect to such period), (ii) be conducted for any Calendar Quarter more than [**] years after the end of the Budget Year of which such Calendar
Quarter is a part, or (iii) be repeated for any Calendar Quarter, 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 or under the applicable Joint Development and Commercialization Agreement. The independent accounting firm shall have the right to make copies of relevant portions of the audited
Party’s books and records; provided that any such copies shall be the Confidential Information of the audited Party, shall be protected by appropriate confidentiality obligations and shall not be shared with the auditing Party or
any other Person. The independent accounting firm will prepare and provide to EISAI and EPIZYME a written report stating only whether the reports submitted and amounts paid hereunder were correct or incorrect, and the amounts of any discrepancies.

 7.9.3 Such examination is to be made at the expense of the auditing Party, except if the results of the audit reveal an
underpayment of royalties, milestone payments, Net Profits/Losses, Development Costs or other amounts to the auditing Party by the audited Party, or an overpayment of Development Costs by the auditing Party to the audited Party, under this Agreement
or under the applicable Joint Development and Commercialization Agreement, as applicable, of [**] percent ([**]%) or more in any Calendar Year, in which case reasonable audit fees for such examination shall be paid by the audited Party. 

  
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 7.9.4 When calculating Net Sales, the amount of such sales in foreign currencies shall be
converted into Dollars using the standard methodologies employed by the audited Party for consolidation purposes. The audited Party shall provide reasonable documentation of the calculation and reconciliation of the conversion figures on a
product-by-product and country-by-country basis as part of its report of Net Sales for the period covered under the applicable report. 
 7.10 Withholding Taxes. EISAI shall inform EPIZYME of any withholding tax obligation imposed by taxing authorities outside of the United States on payments due to EPIZYME under this Agreement or
under the applicable Joint Development and Commercialization Agreement as soon as it becomes aware of the withholding tax obligation. The Parties shall meet promptly thereafter to discuss how best to minimize the amount of such withholding tax
obligation, and EPIZYME shall take all reasonable and lawful steps requested by EISAI to minimize the amount of any such withholding tax obligation at EISAI’s expense. The Parties agree to cooperate in good faith to provide one another
with such documents and certifications as are reasonably necessary to enable EISAI and EPIZYME to minimize or recover any withholding tax payment. EISAI may withhold taxes in the event that revenue authorities in any country outside the United
States require the withholding of taxes on amounts paid hereunder to EPIZYME, and in any such event EISAI shall deduct such taxes from such payment and such taxes shall be paid by EISAI to the proper taxing authority outside of the United States on
behalf of EPIZYME (evidence of which payment to such taxing authority shall be provided promptly by EISAI to EPIZYME hereunder). Notwithstanding the foregoing provisions of this Section 7.10, if EISAI is required by any taxing authority outside
of the United States to withhold taxes from any amount payable by EISAI hereunder, then EISAI shall pay to EPIZYME an 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. 
 7.11 Late Payments. Any undisputed amount owed by
Payor to Payee under this Agreement or under the applicable Joint Development and Commercialization 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 (a) the
prime or equivalent rate per annum quoted by The Wall Street Journal, Eastern Edition on the first Business Day after such payment is due, plus [**] basis points, and (b) the highest rate permitted by applicable Law, in either case
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). 
 7.12 Limitations on Payments
for [**] Use. Notwithstanding anything herein to the contrary, except as otherwise set forth in the last sentence of this Section 7.12, the royalties in Section 7.5.1 shall not apply to [**], provided, that EISAI may not sell
any [**] unless and until the Parties have mutually agreed upon the royalties payable on Net Sales of such [**], as applicable, in accordance with this Section 7.12, or EISAI elects, in its sole discretion and by written notice to EPIZYME, to
sell such [**], as applicable, subject to payment of the royalties set forth in Section 7.5.1 with respect to such [**], as applicable. In the event that EISAI Develops a [**], the Parties shall negotiate [**] adjustment to the royalties set
forth in Section 7.5.1 for the sale of such [**] that reflects the commercial potential of such product and standard 

  
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commercial terms in the industry for [**], as applicable (it being understood that EISAI may elect, in its sole discretion and upon written notice to EPIZYME, to sell such [**], as applicable,
subject to payment of the royalties set forth in Section 7.5.1 with respect to such [**], as applicable). 
 ARTICLE 8

 EXCLUSIVITY; CHANGE OF CONTROL 
 8.1 Target Exclusivity. Except pursuant to this Agreement or any Joint Development and Commercialization Agreement, during the Term, neither Party nor any of its respective Affiliates shall, except
as otherwise permitted in Section 8.2, either (a) alone or with or for any Third Party, Develop, Manufacture (for Development or Commercialization), or Commercialize in the Field any Compounds directed to EZH2, or (b) grant a license
or sublicense to, or otherwise assist or contract with any Third Party, to Develop, Manufacture (for Development or Commercialization), or Commercialize in the Field any Compounds directed to EZH2. 

8.2 Exceptions. Notwithstanding the foregoing: 
 8.2.1 If a Change of Control Event occurs with respect to EPIZYME, and the Person that acquires, combines with or comes to control EPIZYME or acquires EPIZYME’s assets as a result of such Change of
Control Event (or any of such Person’s then-existing Affiliates) already has a program or business that existed prior to the Change of Control Event that would otherwise violate Section 8.1 above at the time of such Change of Control Event
(such program or business, to the extent that the conduct thereof would otherwise violate Section 8.1, a “Competing Business”), such Person (or such Person’s Affiliate) shall be permitted to continue such Competing
Business after such Change of Control Event and such continuation shall not constitute a violation of Section 8.1 above, provided that: 
 (a) none of the EPIZYME IP, Collaboration IP owned by either Party, or any Joint IP shall be used in such Competing Business; 
 (b) the Development activities of EPIZYME under this Agreement shall be conducted separately (including by separate personnel) from any Development activities of EPIZYME directed to such Competing
Business, including the maintenance of separate lab notebooks and records; and 
 (c) if such Person (or such Person’s
Affiliate) does not divest or permanently cease such Competing Business (or, in case the Competing Business is conducted by such Person’s Affiliate, such Person does not divest such Affiliate) within [**] months after such Change of Control
Event, EISAI shall have the right, in its sole and absolute discretion, upon immediate written notice given to EPIZYME at any time within the sixty (60) day period following the end of such [**] month period, to terminate: 

(i) EPIZYME’s Profit-Sharing Options with respect to all remaining Licensed Compounds, in which event such Profit-Sharing Options
shall be of no further force or effect; and 

  
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 (ii) any or all Joint Development and Commercialization Agreements then in effect with
respect to all Shared Products, in which event: 
 (A) Such Shared Products shall be deemed to no longer be Shared Products for
purposes of this Agreement (but, for purposes of clarity, shall remain Licensed Products hereunder); 
 (B) The full milestone
payments specified in Sections 7.3 and 7.4 shall apply again following the termination of such Joint Development and Commercialization Agreements (i.e., without the adjustments set forth in Section 6.2(i) or Section 6.2(j)),
provided that any milestone event achieved prior to such termination (including any sales milestone achieved at a threshold adjusted pursuant to Section 6.2(j)) shall not be achievable again after such termination based on
Development or Commercialization of such Licensed Product; 
 (C) The full royalty payments specified in Section 7.5 and,
to the extent applicable prior to EPIZYME’s exercise of the applicable Profit-Sharing Option, Section 7.12 shall apply again with respect to the applicable Licensed Products (i.e., the elimination of royalties with respect to the
Shared Product in the United States set forth in Section 6.2(e) shall no longer apply); 
 (D) The Parties shall perform a
final reconciliation of applicable Net Profits/Losses incurred from the date the Profit-Sharing Option is exercised through the effective date of the termination of such Joint Development and Commercialization Agreements as provided in the
applicable Joint Development and Commercialization Agreements, and, following such termination of such Joint Development and Commercialization Agreements, neither Party shall have any further right or obligation to share in Net Profits/Losses with
respect to such Licensed Products pursuant to Section 7.6. For purposes of clarity, EISAI shall thereafter have the sole right and responsibility, at its own cost and expense, for the Development and Commercialization of such Licensed Products
under and in accordance with this Agreement; and 
 (E) All such Joint Development and Commercialization Agreements shall
terminate. 
 8.2.2 If either Party or any of its Affiliates merges or consolidates (in a transaction that does not constitute a
Change of Control Event) with, or acquires, a Third Party with a Competing Business, or if either Party or any of its Affiliates acquires assets that include a Competing Business, in any case pursuant to a transaction or series of transactions in
which the acquisition of the Competing Business is ancillary to and not a principal focus of the transaction or series of transactions, then such continuing operation of the Competing Business for up to [**] months following the closing of such
transaction or the first of any series of transactions shall not constitute a breach of Section 8.1, if the Party within [**] months after the closing date of such transaction or the first of any series of transactions either divests, or causes
the relevant Affiliate to divest, the Competing Business, or permanently ceases, or causes the relevant Affiliate to permanently cease, operations of the Competing Business; provided that, in no event shall either Party or any of its
Affiliates be permitted to merge or consolidate with, or acquire, a Third Party 

  
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that is in a Competing Business, or acquire assets that include a Competing Business, pursuant to a transaction or series of transactions in which the acquisition of the Competing Business is the
principal focus of the transaction or series of transactions; and 
 8.2.3 Upon the expiration of all payment obligations with
respect to all Licensed Products in a given country(ies) in the Territory or, if EPIZYME has exercised its Profit-Sharing Option with respect to a Shared Product, upon the expiration of the applicable Profit-Share Term in the United States, the
exclusivity obligations set forth in Section 8.1 shall terminate as to such country(ies). 
 8.3 Uncured Material Breach
After Change of Control. If, at any time after a Change of Control Event occurs with respect to EPIZYME, EISAI has the right to terminate this Agreement pursuant to Section 13.3.1(a) based on an uncured material breach by EPIZYME, in lieu
of such termination of this Agreement EISAI shall have the right, in its sole and absolute discretion, upon immediate written notice given to EPIZYME at any time within the sixty (60) day period following the date that such right to terminate
this Agreement is finally determined, to terminate: 
 8.3.1 EPIZYME’s Profit-Sharing Options with respect to all remaining
Licensed Compounds, in which event such Profit-Sharing Options shall be of no further force or effect; and 
 8.3.2 any or all
Joint Development and Commercialization Agreements then in effect with respect to all Shared Products, in which event the effects set forth in Section 8.2.1(c)(ii)(A)-(E) shall apply. 

ARTICLE 9 

INTELLECTUAL PROPERTY RIGHTS 
 9.1 Ownership. 
 9.1.1 Intellectual Property Arising Outside of this
Agreement. As between the Parties, EPIZYME shall retain all of its right, title and interest in, to and under the EPIZYME IP, and EISAI shall retain all of its rights, title and interest in, to and under the EISAI IP, except to the extent that
any such rights are expressly licensed by one Party to the other Party under this Agreement. 
 9.1.2 Intellectual Property
Arising Under This Agreement. 
 (a) EISAI shall be the sole owner of any EISAI Collaboration Know-How and EISAI
Collaboration Patents, and EISAI shall retain all of its right, title and interest thereto, except to the extent that any rights or licenses are expressly granted thereunder by EISAI to EPIZYME under this Agreement. 

(b) EPIZYME shall be the sole owner of any EPIZYME Collaboration Know-How and EPIZYME Collaboration Patents, 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 EISAI under this Agreement. 

  
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 (c) Any Joint Patents or Joint Know-How shall be owned jointly by EISAI and EPIZYME, and
all rights, title and interest thereto shall be jointly owned by the Parties, subject to any rights or licenses that are expressly granted 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 contained herein, each Party shall be entitled to practice and license the Joint Know-How and the Joint Patents 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 Laws to require any such consent or accounting. 

9.2 Prosecution and Maintenance of Patents. 
 9.2.1 EPIZYME Patents; Collaboration Patents Owned by EPIZYME; Joint Patents. Subject to Section 9.2.3 and Section 9.6: 

(a) As between the Parties, EPIZYME shall have the right (but not the obligation) to Prosecute and Maintain the EPIZYME Patents,
Collaboration Patents owned by EPIZYME, and Joint Patents. EPIZYME shall keep EISAI 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 EISAI with a reasonable opportunity to substantively comment on Prosecution and Maintenance of EPIZYME
Patents, Collaboration Patents owned by EPIZYME, and Joint Patents prior to taking material actions (including the filing of initial applications), and will in good faith consider any actions recommended by EISAI. EISAI shall have the right to
review and make comments on and recommendations in relation to the Prosecution and Maintenance of such Patents; provided that EISAI does so promptly and consistent with any applicable filing deadlines. 

9.2.2 EISAI Patents; Collaboration Patents Owned by EISAI. Subject to Section 9.2.3: 

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

(b) EISAI shall also provide EPIZYME with a reasonable opportunity to substantively comment on the Prosecution and Maintenance of the
Collaboration Patents owned by EISAI 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 Collaboration Patents; provided that EPIZYME does so promptly and consistent with any applicable filing deadlines. 

  
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 9.2.3 Filing Decision or Prosecution Lapse. Subject to Section 9.6, if, during
the Term, the Party with the first right, pursuant to Section 9.2.1 or 9.2.2, to Prosecute and Maintain an EPIZYME Patent, Collaboration Patent or Joint 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 on 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. 
 9.2.4 Cooperation Regarding the Filing and Prosecution of Patents. 

(a) The Parties agree to cooperate fully in the preparation, filing, prosecution, and maintenance of the EPIZYME Patents that are
primarily applicable to EZH2 or EZH2 Compounds, Collaboration Patents, and Joint Patents in the Territory under this Agreement. Cooperation shall include: 
 (i) executing all papers and instruments, or requiring its employees or contractors to execute such papers and instruments, so as to (A) effectuate the ownership of intellectual property set forth in
Section 9.1, (B) enable the other Party to apply for and to prosecute Patent applications in the Territory, and (C) obtain and maintain any Patent extensions, supplementary protection certificates, and the like with respect to the
EISAI Patents, EPIZYME Patents that are primarily applicable to EZH2 or EZH2 Compounds, Collaboration Patents, or Joint Patents, each of (A), (B), and (C) to the extent provided for in this Agreement; 

(ii) consistent with this Agreement, assisting in any license registration processes with applicable governmental authorities that may
be available in the Territory for the protection of a Party’s interests in this Agreement; and 
 (iii) promptly informing
the other Party of any matters coming to such Party’s attention that may materially affect the preparation, filing, prosecution, or maintenance of any EPIZYME Patents that are primarily applicable to EZH2 or EZH2 Compounds, Collaboration
Patents, or Joint Patents in the Territory. 
 (b) At either Party’s request, the Parties shall cooperate with one another
to file and prosecute divisional Patent applications with respect to EPIZYME Patents that are primarily applicable to EZH2 or EZH2 Compounds, Collaboration Patents and Joint Patents for which either Party is responsible for Prosecution and
Maintenance pursuant to this Section 9.2, if practicable and if necessary or desirable to divide subject matter relating to the Development, Manufacture or Commercialization of Licensed Compounds and Licensed Products from other subject matter.

  
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 9.2.5 United States Law. The determination of whether Know-How discovered, developed,
invented, conceived or reduced to practice made by a Party for the purpose of allocating proprietary rights (including Patent or other intellectual property rights) therein, shall, for purposes of this Agreement, be made in accordance with Law in
the United States as in effect on the Effective Date. 
 9.2.6 CREATE Act. Notwithstanding anything to the contrary in
this Article 9, neither Party shall have the right to make an election under the Cooperative Research and Technology Enhancement Act of 2004, 35 U.S.C. § 103(c)(2)-(c)(3) (the “CREATE Act”) when exercising its rights under this
Article 9 without the prior written consent of the other Party. With respect to any such permitted election, the Parties shall use reasonable efforts to cooperate and coordinate their activities with respect to any submissions, filings or other
activities in support thereof. The Parties acknowledge and agree that this Agreement is a “joint research agreement” as defined in the CREATE Act. 
 9.3 Patent Costs. Except as may otherwise be provided in a Joint Development and Commercialization Agreement, each Party shall be responsible for all costs and expenses associated with its
Prosecution and Maintenance activities under Section 9.2. 
 9.4 Defense of Claims Brought by Third Parties. If a
Party becomes aware of any claim, suit, or proceeding alleging that the Development, Manufacture or Commercialization of a Licensed Compound or Licensed Product infringes the intellectual property rights of any Third Party, such Party shall promptly
notify the other Party. Subject to Article 12, each Party shall have the first right, but not the obligation, to defend and control the defense of any such claim, suit, or proceeding brought against such Party at its own expense (but, in the case of
EISAI, subject to deduction as provided below), using counsel of its own choice. The other Party may participate in any such claim, suit, or proceeding with counsel of its choice at its own expense. Each Party shall keep the other Party reasonably
informed of all material developments in connection with any such claim, suit, or proceeding. Each Party agrees to provide the other Party with copies of all pleadings filed in such action and to allow the other Party reasonable opportunity to
participate in the defense of the claims. EISAI shall be entitled to credit [**] percent ([**]%) of the reasonable out-of-pocket costs of defending such claim, suit, or proceeding against royalties due to EPIZYME pursuant to Section 7.5.1 of
this Agreement. Any recoveries by EISAI of any sanctions awarded to EISAI and against a party asserting a claim being defended under this Section 9.4 shall be applied as follows: such recovery shall be applied first to (i) reimburse EISAI
for its reasonable out-of-pocket costs of defending such claim, suit or proceeding to the extent not credited against royalties pursuant to the previous sentence, and (ii) reimburse EPIZYME for royalty credits pursuant to the previous sentence,
and to the extent the amount of recovery is not sufficient to reimburse the Parties for the total amount described under subsections (i) and (ii) above, the recovery shall be shared by the Parties equally. The balance of any such
recoveries shall be included in Net Sales for the relevant Licensed Product. 
 9.5 Enforcement of EPIZYME Patents,
Collaboration Patents and Joint Patents. 
 9.5.1 Duty to Notify of Infringement. If any Party learns of an
infringement or threatened infringement by a Third Party with respect to any EPIZYME Patent, Collaboration Patent or Joint Patent, including actual or alleged infringement under 35 U.S.C. § 271(e)(2), that is or would be competitive with a
Licensed Compound or Licensed Product (“Competitive Infringement”), such Party shall promptly notify the other Party and shall provide such other Party with available evidence of such Competitive Infringement. 

  
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 9.5.2 Enforcement of EPIZYME Patents. Subject to Section 9.6, as between the
Parties, EISAI shall have the primary right, but not the obligation, to institute, prosecute, control and settle any action or proceeding with respect to any Competitive Infringement of EPIZYME Patents, 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 EISAI fails to bring an action or proceeding or otherwise take affirmative actions to address such infringement 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 or any ex-U.S. equivalent of the Hatch-Waxman Act), as between the Parties, EPIZYME shall have
the right to bring and control such an action by counsel of its own choice, and EISAI shall have the right to be represented in any such action by counsel of its own choice at its own expense. 

9.5.3 Enforcement of Collaboration Patents and Joint Patents that Cover Licensed Compounds. EISAI shall have the primary right,
but not the obligation, to institute, prosecute, control and settle any action or proceeding with respect to any Competitive Infringement of Collaboration Patents and Joint Patents, 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 EISAI fails to bring an action or proceeding or otherwise take affirmative actions to address such infringement 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 or any ex-U.S. equivalent of the Hatch-Waxman Act), EPIZYME shall have the right to bring and control such an
action by counsel of its own choice, and EISAI shall have the right to be represented in any such action by counsel of its own choice at its own expense. 
 9.5.4 EISAI Patents. EISAI shall have the sole right, at its own expense, to institute, prosecute, control and settle any action or proceeding with respect to any infringement of the EISAI Patents,
by counsel of its own choice. 
 9.5.5 Settlement. Subject to Section 9.6, a settlement or consent judgment or other
voluntary final disposition of a suit under this Section 9.5 may be entered into without the consent of the Party not bringing suit; provided that (a) any such settlement, consent judgment or other disposition of any action
or proceeding by a Party under this Article 9 shall not, without the consent of the Party not bringing suit, impose any liability or obligation on such Party not bringing suit, (b) the Party bringing suit shall not settle, enter into a consent
judgment or dispose of any such claim, suit or proceeding, except in a manner that it believes in good faith is in the best interests of the Licensed Products (without taking into consideration products in such Party’s portfolio that are not
Licensed Products) and (c) any such settlement, consent judgment or other disposition of any action or proceeding by a Party under this Article 9 shall not, without the consent of the Party not bringing suit, conflict with or reduce the scope
of the subject matter claimed in any Patent owned (solely or jointly) by the Party not bringing suit. 
 9.5.6
Cooperation. If one Party brings any such action or proceeding in accordance with this Section 9.5, the other Party agrees to be joined as a party plaintiff where legally required to initiate or maintain suit or collect damages, and to
give the first Party reasonable assistance and authority to file and prosecute the suit. 

  
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 9.5.7 Costs and Recoveries. Subject to Section 9.6, except as may otherwise be
provided in a Joint Development and Commercialization Agreement, the costs and expenses of the Party bringing suit under this Section 9.5 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) then any remaining proceeds shall:

 (i) in the case of such suits with respect to Competitive Infringement relating to a Licensed Compound or Licensed Product,
other than a Shared Product in the United States, be allocated between the Parties such that the Party bringing suit under this Section 9.5 retains two-thirds and the other Party retains one-third of such amount; 

(ii) in the case of such suits with respect to Competitive Infringement relating to a Shared Product in the United States, be included
in Net Profits/Losses with respect to such Shared Product; and 
 (iii) in the case of all other suits brought under this
Section 9.5, be retained by the Party controlling such action. 
 9.5.8 Regulatory Data Protection. To the extent
required by Law, EISAI shall use Commercially Reasonable Efforts to promptly, accurately and completely list, with the applicable Regulatory Authorities during the Term, all applicable Patents for any Licensed Product that EISAI intends to, or has
begun to, Commercialize 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 and all so called
“Patent Register” listings as required in Canada. Prior to such listings, the Parties shall meet to evaluate and identify all applicable Patents. Notwithstanding the preceding sentence, except as may otherwise be provided in a Joint
Development and Commercialization Agreement and subject to Section 9.6, EISAI shall retain final decision-making authority as to the listing of all applicable Patents for such Licensed Product, regardless of which Party owns such Patent.

 9.5.9 Patent Term Extensions. EPIZYME and EISAI shall discuss and seek to reach mutual agreement for which, if any, of
the Patents within the EPIZYME Patents, Collaboration Patents, Joint Patents or EISAI Patents the Parties shall apply to obtain patent term extensions, adjustments, restorations, or supplementary protection certificates under Law, based on the best
commercial interests of the Licensed Products Covered by such Patents. If the Parties are unable to reach mutual agreement, subject to Section 9.6, as between the Parties, EISAI shall have the right to make the final decision, provided
that, if EISAI determines to extend an EISAI Patent in the Territory, but an EPIZYME Patent, Collaboration Patent or Joint Patent could have been extended instead, then the claims in such EPIZYME Patent, Collaboration Patent or Joint Patent
shall continue, for purposes of determining the affected Royalty Term, to be deemed “Valid Claims” throughout the term of the extension that was available for such Patent, notwithstanding that they will have earlier expired. 

  
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 9.6 Coordination with UNC License Agreement. Notwithstanding anything to the contrary
herein, all rights of EISAI set forth in this Article 9 are subject to the rights of, and obligations to, UNC under the UNC License Agreement, as further set forth in Articles 8 and 9 of the UNC License Agreement. 

9.7 Invalidity or Unenforceability Defenses or Actions. 
 9.7.1 Notice. If a Third Party asserts, as a defense or as a counterclaim in any infringement action under Section 9.5 or claim or counterclaim asserted under Section 9.4, or in a
declaratory judgment action or similar action or claim filed by such Third Party, in either case that any EPIZYME Patent, Collaboration Patent or Joint Patent is invalid or unenforceable, then the Party pursuing such infringement action, or the
Party first obtaining knowledge of such assertion shall promptly give written notice to the other Party. 
 9.7.2
Defense. Subject to Section 9.6, the right to defend the applicable EPIZYME Patent, Collaboration Patent or Joint Patent against such assertion of invalidity or unenforceability shall be determined in the same manner as the right to
enforce such Patent pursuant to Section 9.5; provided that, (a) if the assertion is made in a suit that is already being controlled by a Party pursuant to Section 9.4 or 9.5, the controlling Party shall retain control of such defense
and (b) other than as provided in the foregoing clause (a), EISAI shall only have the right to defend EPIZYME Patents that are primarily applicable to EZH2 or EZH2 Compounds against such assertions. The other Party may participate in any such
claim, suit, or proceeding with counsel of its choice at its own expense. If a Party elects not to defend or control the defense of the EPIZYME Patents, Collaboration Patents or Joint Patents, or otherwise fails to initiate and maintain the defense
of any such claim, suit, or proceeding, then the other Party may conduct and control the defense of any such claim, suit, or proceeding at its own expense. 
 9.7.3 Cooperation. Each Party shall assist and cooperate with the other Party as such other Party may reasonably request from time to time in connection with its activities set forth in this
Section 9.7, including by being joined as a party plaintiff in such action or proceeding, providing access to relevant documents and other evidence, and making its employees available at reasonable business hours. In connection with any such
defense or claim or counterclaim, the controlling Party shall consider in good faith any comments from the other Party and shall keep the other Party reasonably informed of any steps taken, and shall provide copies of all documents filed, in
connection with such defense, claim, or counterclaim. In connection with the activities set forth in this Section 9.7, each Party shall consult with the other as to the strategy for the defense of the EPIZYME Patents, Collaboration Patents and
Joint Patents. 
 9.8 Third Party Licenses. If in the reasonable opinion of EISAI, the Development, Manufacture, or
Commercialization of any Licensed Compound or Licensed Product by EISAI, any of its Affiliates, or any of its or their Sublicensees infringes or misappropriates any Patent, trade secret, or other intellectual property right of a Third Party in any
country in the Territory, such that EISAI, any of its Affiliates or any of its or their Sublicensees cannot Develop, 

  
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Manufacture, or Commercialize such Licensed Compound or Licensed Product in such country without infringing such Patent, trade secret, or other intellectual property right of such Third Party,
then EISAI shall have the right, but not the obligation, to negotiate and obtain a license from such Third Party as necessary for EISAI and its Affiliates, and its and their Sublicensees to Develop, Manufacture, and Commercialize Licensed Compounds
and Licensed Products in such country. 
 9.9 Ownership and Prosecution of Product Trademarks. EISAI shall own all right,
title, and interest to the trademarks used with respect to the Licensed Products in the Territory, and shall be responsible for the registration, prosecution, maintenance and enforcement thereof. 

ARTICLE 10 

CONFIDENTIALITY 
 10.1 Confidentiality; Exceptions. Except to the extent expressly authorized by this Agreement or otherwise agreed in writing, 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 or other information and materials, patentable or otherwise, in any form (written,
oral, photographic, electronic, magnetic, or otherwise) which is disclosed to it by the other Party (the “Disclosing Party”) or otherwise received or accessed by a Receiving Party in the course of performing its obligations or
exercising its rights under this 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 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, or learned by, the Receiving Party, or was otherwise developed independently by 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; 
 (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 had no obligation to the Disclosing Party not to disclose such information to others.

 10.2 Product Information. EPIZYME recognizes that by reason of, inter alia, EISAI’s status as an exclusive
licensee under this Agreement, EISAI has an interest in EPIZYME’s retention in confidence of certain information of EPIZYME. Accordingly, until the end of the Term, EPIZYME shall keep confidential, and not publish or otherwise disclose, and not
use for 

  
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any purpose other than to fulfill EPIZYME’s obligations, or exercise EPIZYME’s rights, hereunder any EPIZYME Know-How Controlled by EPIZYME or EPIZYME Collaboration Know-How, in each
case that are primarily applicable to EZH2 or EZH2 Compounds (the “Product Information”), except to the extent (a) the Product Information is in the public domain through no fault of EPIZYME, (b) such disclosure or use is
expressly permitted under Section 10.3, or (c) such disclosure or use is otherwise expressly permitted by the terms and conditions of this Agreement. For purposes of Section 10.3, each Party shall be deemed to be both the Disclosing
Party and the Receiving Party with respect to Product Information. For clarification, the disclosure by EPIZYME to EISAI of Product Information shall not cause such Product Information to cease to be subject to the provisions of this
Section 10.2 with respect to the use and disclosure of such Confidential Information by EPIZYME. In the event this Agreement is terminated pursuant to Article 13, this Section 10.2 shall have no continuing force or effect, but the Product
Information, to the extent disclosed by EPIZYME to EISAI hereunder, shall continue to be Confidential Information of EPIZYME, subject to the terms of Sections 10.1 and 10.3 for purposes of the surviving provisions of this Agreement. Each Party shall
be responsible for compliance by its Affiliates, and its and its Affiliates’ respective officers, directors, employees and agents, with the provisions of Section 10.1 and this Section 10.2. 

10.3 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) under appropriate confidentiality provisions similar to
those in this Agreement, in connection with the performance of its obligations or exercise of rights granted or reserved in this Agreement (including the rights to Develop and Commercialize Licensed Compounds or Licensed Products and to grant
licenses and sublicenses hereunder and, with respect to EPIZYME, to comply with its obligations to UNC under the UNC License Agreement); 
 (b) to Regulatory Authorities as required in connection with any filing, application or request for Regulatory Approval; provided, however, that reasonable measures shall be taken to
assure confidential treatment of such information; 
 (c) in response to a valid order of a court of competent jurisdiction or
other supra-national, federal, national, regional, state, provincial and local governmental or regulatory body of competent jurisdiction or, if so advised by the Receiving Party’s legal counsel, such disclosure is otherwise required by Law,
including by reason of filing with securities regulators; provided, however, that, to the extent practicable, the Receiving Party shall first have given notice to the Disclosing Party and given the Disclosing Party a reasonable
opportunity to quash such order or to obtain a protective order or confidential treatment requiring that the Confidential Information and documents that are the subject of such order be held in confidence by such court or agency or, if disclosed, be
used only for the purposes for which the order was issued; and provided further that the Confidential Information disclosed in response to such court or governmental order shall be limited to that information which is legally
required to be disclosed in response to such court or governmental order; 

  
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 (d) to a patent authority as may be reasonably necessary or useful for purposes of
obtaining or enforcing a Patent with respect to which the Receiving Party has the right or responsibility to conduct such activities hereunder; provided, however, that reasonable measures shall be taken to assure confidential
treatment of such information, to the extent such protection is available; 
 (e) in communication with actual or potential
investors, lenders, acquirors, merger partners, consultants, advisors, licensees, sublicensees, collaborators or others on a need to know basis, in each case under appropriate confidentiality provisions substantially equivalent to those of this
Agreement; or 
 (f) to the extent mutually agreed to in writing by the Parties. 

10.4 Press Release; Disclosure of Agreement. 
 10.4.1 Press Release. On or promptly after the Effective Date, the Parties shall jointly issue a public announcement of the execution of this Agreement in the form attached hereto as Exhibit
F. Thereafter, the Parties shall use good faith efforts to agree on joint press releases with respect to material developments relating to the Development or Commercialization of Licensed Products; provided that EPIZYME shall have the right,
without having to obtain EISAI’s consent, to issue press releases or make other public announcements or disclosures with respect to Development or Commercialization milestone achievements or payments relating to any milestone specified in this
Agreement if the Parties cannot agree on a joint press release with respect thereto within [**] Business Days after EPIZYME notifies EISAI of EPIZYME’s desire to issue such press release. 

10.4.2 Disclosure of Agreement Terms. 
 (a) Except to the extent required by Law or by securities exchange listing requirements or as otherwise permitted in accordance with Section 10.4.1, neither Party shall make any public announcements
concerning this Agreement or the subject matter hereof without the prior written consent of the other, which shall not be unreasonably withheld, conditioned or delayed. 
 (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 to the extent such information remains accurate. Each Party shall also be permitted to disclose the terms of this Agreement, in each case under appropriate confidentiality provisions substantially equivalent to those
of this Agreement, to any actual or potential acquirors, merger partners, licensees, sublicensees, collaborators, investors, lenders and professional advisors. 
 (c) 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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 10.5 Termination of Prior Confidentiality Agreement. This Agreement supersedes and
replaces the Confidentiality Agreement between EPIZYME and EISAI dated July 13, 2010 (the “Existing Confidentiality Agreement”). All information exchanged between the Parties under the Existing Confidentiality Agreement shall
be deemed Confidential Information hereunder and shall be subject to the terms of this Article 10. 
 10.6 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 10. 
 10.7 Publications. 

10.7.1 Restrictions on Publication. Neither Party nor its Affiliates shall publish or publicly disclose the results generated in
the course of performing any of the Development or Commercialization activities directed to EZH2 conducted by either Party under this Agreement without the prior written consent of the other Party, except as otherwise expressly permitted in this
Section 10.7, in Section 10.8 or otherwise in this Agreement. The Parties recognize that it may be useful or required to publish or publicly disclose the results of Development activities conducted hereunder, and each Party (and its
Affiliates and Sublicensees) shall be free to publish or publicly disclose such results, subject to the prior review by the other Party for patentability and protection of its Confidential Information as described in this Section 10.7.

 10.7.2 Submission; Review. The Party seeking to publish 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.
The reviewing Party shall respond in writing promptly and in no event later than [**] days ([**] Business Days in the case of abstracts) 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 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 Development activities conducted under this Agreement; or 

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

10.7.3 Patent and Trade Secret Protection. In the event of concern by the reviewing Party 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

  
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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. Any Confidential Information of the reviewing Party shall, if
requested by the reviewing Party, be removed. 
 10.7.4 Review of Third Party Materials. With respect to any proposed
abstracts, manuscripts or summaries of presentations by investigators or other Third Parties conducting Development with or on behalf of a Party hereunder, such materials shall be subject to review by the other Party under this Section 10.7 to
the same extent that EISAI or EPIZYME (as the case may be) has the right to do so. 
 10.8 Clinical Trial Register. Each
of EISAI and EPIZYME shall have the right to list and publish summaries of data and results from any human clinical trials conducted by such 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 discuss and reasonably cooperate in order to facilitate the process to be employed
in order to ensure the publication of any such summaries of human clinical trials data and results as required on the clinical trial registry of each Party and any government-sponsored database such as clinicaltrials.gov or other publicly available
websites such as www.clinicalstudyresults.org, and shall provide copies of such summaries to the other Party at least [**] days prior to the proposed publication date for the purposes of preparing any necessary patent filings. 

10.9 Use of Name. Except as expressly provided herein, neither Party shall mention or otherwise use the name, logo, or trademark
of the other Party or any of its Affiliates (or any abbreviation or adaptation thereof) in any publication, press release, marketing and promotional material, or other form of publicity without the prior written approval of such other Party in each
instance. The restrictions imposed by this Section 10.9 shall not prohibit either Party from making any disclosure identifying the other Party that is required by Law. In addition, EPIZYME may use EISAI’s name, logo or trademark on
EPIZYME’s website to identify EISAI as one of EPIZYME’s collaborators provided that EPIZYME complies with the formatting specifications provided by EISAI. 
 10.10 Return of Confidential Information. Upon the effective date of expiration or termination of this Agreement for any reason, either Party may request in writing, and the other Party
shall either, with respect to Confidential Information (in the event of termination of this Agreement with respect to one or more Terminated Territories but not in its entirety, solely to the extent relating to such Terminated Territories) to which
such first Party does not retain rights under the surviving provisions of this Agreement: (i) promptly destroy all copies of such Confidential Information in the possession of the other Party and confirm such destruction in writing to the
requesting Party; or (ii) promptly deliver to the requesting Party, at the other Party’s expense, all copies of such Confidential Information in the possession of the other Party; provided, however, that the other
Party shall be permitted to retain such Confidential Information for the sole purpose of performing any continuing obligations hereunder or exercising its rights hereunder that survive such termination (e.g., in the case of EPIZYME, the
exercise of its rights 

  
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under the license grant back). Notwithstanding the foregoing, such other Party also shall be permitted to retain one (1) copy of such Confidential Information for archival purposes and such
additional copies of, or any computer records or files containing, such Confidential Information that have been created solely by such Party’s automatic archiving and back-up procedures, to the extent created and retained in a manner consistent
with such other Party’s standard archiving and back-up procedures, but not for any other use or purpose. All Confidential Information shall continue to be subject to the terms of this Agreement for the period set forth in Section 13.6.2.

 ARTICLE 11 
 REPRESENTATIONS AND WARRANTIES 
 11.1 Representations and Warranties of
Both Parties. Each Party hereby represents, warrants and covenants to the other Party, as of the Effective Date, that: 

11.1.1 Such Party is duly organized, validly existing and in good standing under the Laws of the jurisdiction of its incorporation and
has full corporate power and authority to enter into this Agreement and to carry out the provisions hereof; 
 11.1.2 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; 
 11.1.3 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;

 11.1.4 The execution, delivery and performance of this Agreement by such Party does not and will not conflict with any
agreement or any provision thereof, or any instrument or understanding, oral or written, to which it is or becomes a party or by which it is or becomes bound, nor violate any Law or regulation of any court, governmental body or administrative or
other agency having jurisdiction over such Party; 
 11.1.5 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 Laws currently in effect, is necessary for its execution and delivery of this Agreement;
and 
 11.1.6 it has not (i) employed and has not used a contractor or consultant that has employed, any Person debarred
pursuant to Section 306 of the Federal Food, Drug and Cosmetic Act (the “FFDCA”), or who is the subject of a conviction described in such section (or subject to a similar sanction of EMA), or, (ii) employed any Person that
is the subject of an FDA debarment investigation or proceeding (or similar proceeding of EMA), in the conduct of any pre-clinical activities or clinical studies of Compounds. 
 11.2 Representations and Warranties of EPIZYME. EPIZYME hereby represents, warrants and covenants to EISAI, as of the Effective Date, that: 

11.2.1 All EPIZYME Patents (except for the In-Licensed Patents) and, to EPIZYME’s knowledge, all In-Licensed Patents, in each case
existing as of the Effective Date 

  
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are listed on Exhibit B (such EPIZYME Patents existing as of the Effective Date, collectively, the “Existing Patents”). To EPIZYME’s knowledge, no issued patents
included in the Existing Patents are invalid or unenforceable. 
 11.2.2 The Compounds listed on Exhibit G are among the
Licensed Compounds identified and Controlled by EPIZYME as of the Effective Date. 
 11.2.3 There are no claims, judgments or
settlements against, or amounts with respect thereto, owed by EPIZYME or any of its Affiliates relating to the Existing Patents (except for the In-Licensed Patents) or the EPIZYME Know-How existing as of the Effective Date (except for EPIZYME
Know-How in-licensed from UNC under the UNC License Agreement (the “In-Licensed Know-How”)), or, to EPIZYME’s knowledge, owed by UNC relating to the In-Licensed Patents or In-Licensed Know-How existing as of the Effective Date
(such EPIZYME Know-How existing as of the Effective Date, collectively, the “Existing Know-How”). No claim or litigation has been brought or threatened against EPIZYME or any of its Affiliates by any Person alleging, and EPIZYME has
no knowledge of any claim, whether or not asserted, that (a) the Existing Patents are invalid or unenforceable or (b) the Existing Patents or the Existing Know-How or the disclosing, copying, making, assigning or licensing of the Existing
Patents or the Existing Know-How, or the Development or Commercialization of the Licensed Compounds or Licensed Products as contemplated herein, violates, infringes or otherwise conflicts or interferes with, or would violate, infringe or otherwise
conflict or interfere with, any intellectual property or proprietary right of any Person. 
 11.2.4 EPIZYME is the sole and
exclusive owner of the Existing Patents listed on Exhibit B, Part 1 (the “Owned Patents”) and the Existing Know-How (other than In-Licensed Know-How), free of any encumbrance, lien or claim of ownership by any Third Party. To
EPIZYME’s knowledge, except for (i) rights of the U.S. government, and (ii) rights reserved by UNC and the Howard Hughes Medical Institute under the UNC License Agreement, EPIZYME is the sole and exclusive licensee of the Existing
Patents listed on Exhibit B, Part 2 (the “In-Licensed Patents”). EPIZYME is entitled to grant to EISAI the licenses specified herein. The Owned Patents and In-Licensed Patents constitute all of the Existing Patents.

 11.2.5 During the Term, EPIZYME shall not encumber or diminish the rights granted to EISAI hereunder with respect to the
EPIZYME Patents, including by (a) using Commercially Reasonable Efforts not to commit any acts or permit the occurrence of any omissions that would cause the breach or termination of the UNC License Agreement, subject to EISAI complying with
Section 5.2 hereof, or (b) not amending or otherwise modifying or permitting to be amended or modified the UNC License Agreement in any way that adversely affects the rights and licenses granted to EISAI, or the obligations of EISAI,
hereunder, without prior written consent of EISAI. EPIZYME shall promptly provide EISAI with notice of any alleged, threatened or actual breach of the UNC License Agreement. 
 11.2.6 To EPIZYME’s knowledge, the Existing Patents are being diligently prosecuted in the respective patent offices in accordance with Law. All applicable filing and maintenance fees with respect to
the Existing Patents, other than the In-Licensed Patents, have been paid on or before the due date for payment, and to EPIZYME’s knowledge, all applicable filing and maintenance fees with respect to the In-Licensed Patents have been paid on or
before the due date for payment. 

  
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 11.2.7 EPIZYME and its Affiliates have not previously assigned, transferred, licensed,
conveyed or otherwise encumbered its or their right, title or interest in or to the Existing Patents that are primarily applicable to EZH2 or EZH2 Compounds, Existing Know-How that are primarily applicable to EZH2 or EZH2 Compounds, or any EZH2
Compound (including by granting any covenant not to sue with respect thereto) or any Patents or Know-How that would be Existing Patents or Existing Know-How, in each case that are primarily applicable to EZH2 or EZH2 Compounds, but for such
assignment, transfer, license, conveyance or encumbrance, except in each case where such assignment, transfer, license, conveyance or encumbrance is terminated and no longer in force or effect, and EPIZYME and its Affiliates will not enter into any
such agreements or grant any such right, title or interest to any Person that is inconsistent with the rights and licenses granted to EISAI under this Agreement. 
 11.2.8 To EPIZYME’s knowledge, no Person is infringing or threatening to infringe the Existing Patents or misappropriating or threatening to misappropriate the Existing Know-How. 

11.2.9 True, complete and correct copies (as of the Effective Date) of: (a) the file wrapper and other material documents relating
to the prosecution, defense, maintenance, validity and enforceability of the Owned Patents and, to the extent in EPIZYME’s possession, the In-Licensed Patents, (b) the UNC License Agreement, and (c) all information known to EPIZYME
that EPIZYME believes to be materially adverse with respect to the safety and efficacy of the EZH2 Compounds listed on Exhibit G, in each case ((a) through (c)) have been provided or made available to EISAI prior to the Effective Date.

 11.2.10 None of EPIZYME, its Affiliates or, to EPIZYME’s knowledge, any Third Party, is in breach of the UNC License
Agreement in any material respect and, to the knowledge of EPIZYME, the UNC License Agreement is in full force and effect. 

11.2.11 To EPIZYME’s knowledge, the conduct of the Development activities under the Research and Development Plan attached hereto as
of the Effective Date will not infringe any Patent or other intellectual property or proprietary right of any Person. 
 11.2.12
The conception, development and reduction to practice of the Existing Patents and Existing Know-How have not constituted or involved the misappropriation of trade secrets or other rights or property of any Person. 

11.2.13 In respect of the pending patent applications included in the Owned Patents, EPIZYME has complied with its duty of candor to
relevant patent offices. 
 11.2.14 The Existing Patents represent all Patents within EPIZYME’s Control relating to EZH2
Compounds as of the Execution Date. To EPIZYME’s knowledge, there is no Know-How Controlled by EPIZYME as of the Effective Date that relates to EZH2 Compounds that is not within the Existing Know-How. 

  
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 11.2.15 To EPIZYME’s knowledge, each of the Existing Patents properly identifies each
and every inventor of the claims thereof as determined in accordance with the laws of the jurisdiction in which such Existing Patent is issued or such application is pending. 
 11.2.16 To EPIZYME’s knowledge, each Person who has or has had any rights in or to any Owned Patent or any Existing Know-How (other than In-Licensed Know-How), has assigned and has executed an
agreement assigning its entire right, title and interest in and to such Owned Patent and Existing Know-How to EPIZYME. 

11.2.17 No material Existing Know-How owned by EPIZYME have been disclosed or authorized to be disclosed to any Third Party not subject
to confidentiality obligations to EPIZYME, and, to EPIZYME’s knowledge, no Third Party to such a nondisclosure agreement with EPIZYME is in breach or default thereof. EPIZYME has implemented reasonable policies and procedures to protect and
maintain the confidentiality of Existing Know-How. 
 11.2.18 All information, documentation and other materials furnished or
made available by EPIZYME upon the request of EISAI during EISAI’s period of diligence prior to the Effective Date or otherwise related to the transaction contemplated hereby are, as of the date such information, documentation or materials were
furnished or made available to EISAI, true, complete and correct copies of what they purport to be, and EPIZYME has disclosed to EISAI any event or circumstance occurring since the date any such information, documentation or materials were furnished
or made available which would have caused such information, documentation or materials not to be true, complete and correct copies of what they purport to be as of the Effective Date. 

11.2.19 EPIZYME and its Affiliates have conducted, and, to EPIZYME’s knowledge, their respective contractors and consultants have
conducted, all Development of Licensed Compounds or the Licensed Products that they have conducted prior to the Effective Date, in accordance with Law. 
 11.2.20 To EPIZYME’s knowledge, with respect to the In-Licensed Patents, UNC has taken all actions necessary under the Bayh-Dole Act to secure ownership of such Patents for UNC. 

11.3 Representation and Warranty of EISAI. EISAI hereby represents and warrants to EPIZYME, as of the Effective Date, that, to
EISAI’s knowledge, neither EISAI nor any Affiliate owns or controls any EZH2 Compounds. 
 11.4 Mutual Covenants.
Each Party hereby covenants to the other Party that: 
 (a) All employees of such Party or its Affiliates working under this
Agreement will be under 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) It shall not use in any capacity, in connection with the performance of the activities contemplated by this Agreement, any Person
who has been debarred pursuant to Section 306 of the FFDCA, or who is the subject of a conviction described in such section (or 

  
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subject to a similar sanction of EMA). It agrees to inform the other Party in writing immediately if it or any Person who is performing services hereunder on its behalf is debarred or is the
subject of a conviction described in Section 306, or if any action, suit, claim, investigation or legal or administrative proceeding is pending or, to its knowledge, is threatened, relating to the debarment or conviction of it or any Person
performing services hereunder; and 
 (c) Neither Party 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. 
 11.5 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, 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, or (b) the safety or usefulness for any purpose of the technology or materials, including any Compounds, it provides or discovers under this Agreement. 

ARTICLE 12 

INDEMNIFICATION; INSURANCE 
 12.1 Indemnification by EISAI. EISAI shall indemnify, defend and hold harmless EPIZYME and its Affiliates, and its and their respective directors, officers, employees and agents, from and against
any and all liabilities, damages, losses, costs and expenses, including the reasonable fees of attorneys and other professional Third Parties (collectively, “Losses”), arising out of or resulting from any and all Third Party suits,
claims, actions, proceedings or demands (“Claims”) based upon: 
 (a) the negligence, recklessness or wrongful
intentional acts or omissions of EISAI or its Affiliates and its or their respective directors, officers, employees and agents, in connection with EISAI’s performance of its obligations or exercise of its rights under this Agreement;

 (b) any breach of any representation or warranty or covenant made by EISAI under Article 11 or any other provision under
this Agreement; or 
 (c) except as may otherwise be provided in a Joint Development and Commercialization Agreement, the
Development that is actually conducted by or on behalf of EISAI, its Affiliates or Sublicensees (excluding any Development carried out by or on behalf of EPIZYME, its Affiliates or Sublicensees hereunder), the handling and storage by or on behalf of
EISAI, its Affiliates or Sublicensees of any chemical agents or other compounds for the purpose of conducting Development by or on behalf of EISAI, its Affiliates or Sublicensees, and the Manufacture and Commercialization by EISAI, its Affiliates or
Sublicensees of any Licensed Compound or Licensed Product, including (i) any product liability, personal injury, property damage or other damage, and (ii) infringement of any Patent or other intellectual property rights of any Third Party,
in each case resulting from any of the foregoing activities described in this Section 12.1(c); 

  
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 in each case, provided that, such indemnity shall not apply to the extent EPIZYME has an
indemnification obligation pursuant to Section 12.2 for such Loss, in which event each Party shall indemnify the other to the extent of their respective liability for such Loss. 

12.2 Indemnification by EPIZYME. EPIZYME shall indemnify, defend and hold harmless EISAI and its Affiliates, and its and their
respective directors, officers, employees and agents, from and against any and all Losses, arising out of or resulting from any and all Third Party Claims based upon: 
 (a) the negligence, recklessness or wrongful intentional acts or omissions 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 covenant made by EPIZYME under Article 11 or any other provision under this Agreement; 
 (c)
except as may otherwise be provided in a Joint Development and Commercialization Agreement, the Development that is actually conducted by or on behalf of EPIZYME, its Affiliates or Sublicensees (excluding any Development carried out by or on behalf
of EISAI or its Affiliates or Sublicensees; provided, however, that the Development which is to be carried out by or on behalf of EPIZYME, its Affiliates or Sublicensees under the Research and Development Plan hereunder shall
not be considered or interpreted to be Development carried out by or on behalf of EISAI or its Affiliates or Sublicensees), the handling and storage by or on behalf of EPIZYME, its Affiliates or Sublicensees of any chemical agents or other compounds
for the purpose of conducting Development by or on behalf of EPIZYME, its Affiliates or Sublicensees, including (i) any product liability, personal injury, property damage or other damage resulting from any Licensed Compound or Licensed Product
distributed by or on behalf of EPIZYME, its Affiliates or Sublicensees, and (ii) infringement of any Patent or other intellectual property rights of any Third Party by EPIZYME, its Affiliates or Sublicensees, in each case resulting from any of
the foregoing activities described in this Section 12.2(c); 
 (d) any gross negligence, recklessness, wrongful
intentional act or omission, failure to comply with any Law, breach of any agreement with a Third Party, or infringement of Patent or other intellectual property rights of any Third Party by EPIZYME, its Affiliates or Third Party sublicensees with
respect to any Development, Commercialization, or Manufacture of Licensed Compounds or Licensed Products anywhere in the world prior to the Effective Date; or 
 (e) the Development, Commercialization, or Manufacture of Compounds, Licensed Compounds or Licensed Products anywhere in the world after the Term or in any Terminated Territory, including the use of
Marketing Related Materials, by or on behalf of EPIZYME or its Affiliates or Third Party sublicensees; 

  
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 in each case, provided that, such indemnity shall not apply to the extent EISAI has an
indemnification obligation pursuant to Section 12.1 for such Loss, in which event each Party shall indemnify the other to the extent of their respective liability for such Loss. 

12.3 Procedure. 
 12.3.1 Notice of Claim. A Person seeking indemnification under this Article 12 (an “Indemnified Party”) shall give prompt written notification to the Party from whom
indemnification is sought (the “Indemnifying Party”) of the Third Party Claim for which indemnification may be sought (it being understood and agreed, however, that the failure by an Indemnified Party to give notice of a Third-Party
Claim as provided in this Section 12.3 shall not relieve the Indemnifying Party of its indemnification obligation under this Agreement except and only to the extent that such Indemnifying Party is actually prejudiced as a result of such failure
to give notice). 
 12.3.2 Assumption of Defense; Participation. Within [**] days after delivery of such notification,
the Indemnifying Party may, upon written notice thereof to the Indemnified Party, assume control of the defense of such Third Party Claim with counsel reasonably satisfactory to the Indemnified Party. If the Indemnifying Party does not assume
control of such defense, the Indemnified Party shall control such defense and, without limiting the Indemnifying Party’s indemnification obligations, the Indemnifying Party shall reimburse the Indemnified Party for all costs and expenses,
including reasonable attorneys’ fees and disbursements, incurred by the Indemnified Party in defending itself within [**] days after receipt of any invoice therefor from the Indemnified Party. The Party not controlling such defense may
participate therein at its own expense; provided, however, that, if the Indemnifying Party assumes control of such defense and the Indemnified Party in good faith concludes, based on written advice from outside counsel, that the
Indemnifying Party and the Indemnified Party have conflicting interests with respect to such Third Party Claim sufficiently adverse to make unadvisable the representation by the same counsel of both Parties under Law, ethical rules or equitable
principles, the Indemnifying Party shall be responsible for the reasonable fees and expenses of a single counsel to the Indemnified Party in connection therewith. The Party controlling such defense shall keep the other Party advised of the status of
such Third Party Claim and the defense thereof and shall consider recommendations made by the other Party with respect thereto. 

12.3.3 Settlements. The Indemnified Party shall not agree to any settlement of such Third Party Claim without the prior written
consent of the Indemnifying Party, which shall not be unreasonably withheld, delayed or conditioned. The Indemnifying Party shall not agree to any settlement of such Third Party Claim or consent to any judgment in respect thereof that does not
include a complete and unconditional release of the Indemnified Party from all liability with respect thereto, that imposes any liability or obligation on the Indemnified Party or that acknowledges fault by the Indemnified Party, without the prior
written consent of the Indemnified Party. 
 12.4 Insurance. 

12.4.1 EPIZYME’s Insurance Obligations. Except as may otherwise be provided in a Joint Development and Commercialization
Agreement, EPIZYME shall maintain, at its cost, 

  
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insurance against liability and other risks associated with its activities and obligations under this Agreement, 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. EPIZYME shall furnish to EISAI evidence of such insurance upon request. 
 12.4.2 EISAI’s Insurance Obligations. Except as may otherwise be provided in a Joint Development and Commercialization Agreement, EISAI shall maintain self-insurance against liability and
other risks associated with its activities and obligations under this Agreement, including its Clinical Trials and the Commercialization of Licensed Products, in such amounts and on such terms as are customary for a company such as EISAI for the
activities to be conducted by it under this Agreement. EISAI shall furnish to EPIZYME evidence of such self-insurance upon request. 
 12.5 LIMITATION OF LIABILITY. EXCEPT FOR A BREACH OF ARTICLE 8 OR ARTICLE 10 OR FOR CLAIMS OF A THIRD PARTY THAT ARE SUBJECT TO INDEMNIFICATION UNDER THIS ARTICLE 12, NEITHER EPIZYME NOR EISAI, 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 13 
 TERM AND TERMINATION 

13.1 Term; Expiration. 
 13.1.1 Term. This Agreement shall become effective on the Effective Date and, unless earlier terminated pursuant to this Article 13, shall remain in effect until the later of (a) expiration of
all payment obligations under this Agreement with respect to all Licensed Products in all countries in the Territory, or (b) if EPIZYME exercises its Profit-Sharing Option with respect to a Licensed Compound, unless otherwise mutually-agreed by
the Parties, the expiration or termination of the last to expire Profit-Share Term under any Joint Development and Commercialization Agreement (the “Term”). 
 13.1.2 Effect of Expiration. After expiration of the Term (but not after early termination) with respect to this Agreement in its entirety pursuant to Section 13.1.1, EISAI shall have a
non-exclusive, fully-paid, royalty-free right and license, with the right to grant sublicenses, under the EPIZYME IP, Collaboration IP owned by EPIZYME, and EPIZYME’s interest in the Joint IP, in each case as used at the time of such
expiration, to continue to Develop and Commercialize Licensed Products in the Field in the Territory, for so long as it continues to do so. 

  
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 13.2 Unilateral Termination by EISAI. 

13.2.1 Termination for Convenience or Safety. 
 (a) EISAI shall have the right, at its sole discretion, exercisable at any time to terminate this Agreement with respect to the entire Territory or one or more Major Market Countries, upon ninety
(90) days’ prior written notice to EPIZYME hereunder. 
 (b) EISAI shall have the right, exercisable at any time to
terminate this Agreement in its entirety immediately upon written notice to EPIZYME hereunder if EISAI in good faith believes that it is not advisable for EISAI to continue to Develop or Commercialize the Licensed Products from a scientific,
regulatory or ethical perspective as a result of a bona fide serious safety issue regarding the use of any Licensed Product. 

13.2.2 Cessation of Activities. Without limiting the generality of Section 13.2.1(a), if EISAI or its designated Affiliate or
Sublicensee in all material respects ceases (or fails to undertake) Development or Commercialization activities with respect to all Licensed Compounds or Licensed Products, either as a whole or with respect to one or more Major Market Countries
(excluding temporary cessation during periods in which EISAI is using Commercially Reasonable Efforts to prepare to resume or commence Development or Commercialization and temporary cessation during periods of [**] months or less in which EISAI is
conducting a strategic review of Licensed Products in order to determine whether to resume or commence Development or Commercialization), then if such cessation or failure is consistent with the exercise of Commercially Reasonable Efforts (and
therefore not a breach of EISAI’s obligations to use Commercially Reasonable Efforts that is a basis for termination by EPIZYME pursuant to Section 13.3), such cessation or failure shall nonetheless be deemed to constitute a termination by
EISAI under Section 13.2.1(a) with respect to the applicable Major Market Country(ies). For clarity, cessation under this Section 13.2.2 with respect to a Major Market Country shall not be deemed to have occurred if (i) EISAI or its
designated Affiliate or Sublicensee is performing Development or Commercialization activities with respect to at least one (1) Licensed Compound or Licensed Product with respect to such Major Market Country or (ii) EISAI or its Affiliate
is engaged in active negotiations with a Third Party in connection with a license or sublicense in such Major Market Country with respect to any Licensed Compound or Licensed Product. 

13.2.3 Termination in Two or More Major Market Countries. For purposes of clarity, notwithstanding anything above in this
Section 13.2 to the contrary: 
 (a) If EISAI exercises its right to terminate with respect to all Major Market Countries
pursuant to Section 13.2.1(a) (or EISAI ceases activities with respect to all Major Market Countries pursuant to Section 13.2.2), then this Agreement shall terminate in its entirety, and the applicable effects of termination set forth in
Section 13.5.1 shall apply; and 
 (b) If EISAI exercises its right to terminate with respect to two (2) or more (but
not all) Major Market Countries pursuant to Section 13.2.1(a) (or EISAI ceases activities with respect to two (2) or more (but not all) Major Market Countries pursuant to Section 13.2.2), then this Agreement shall terminate solely
with respect to such terminated Major Market Countries and the rest of the Territory, but excluding the Major Market Country(ies) which was not terminated, and the effects of termination set forth in Section 13.5.2 shall apply. 

  
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 13.3 Termination for Cause. 

13.3.1 Termination for Material Breach. 
 (a) Either Party (the “Non-Breaching Party”) may, without prejudice to any other remedies available to it under Law or in equity, terminate this Agreement if the other Party (the
“Breaching Party”) shall have materially breached in the performance of its obligations hereunder, and such breach shall have continued for [**] days (or, in the case of a payment breach, [**] days) after written notice thereof was
provided to the Breaching Party by the Non-Breaching Party, such notice describing the alleged breach. Subject to Section 13.3.2, any such termination of this Agreement under this Section 13.3.1 shall become effective at the end of such
[**] day (or [**] day, as applicable) cure period, unless: 
 (i) the Breaching Party has cured such breach prior to the
expiration of such cure period; or 
 (ii) such 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 acceptable to the Non-Breaching Party, and (C) the Breaching Party commits to and does carry out such plan; provided that, unless otherwise mutually agreed by the Parties, in no
event shall such suspension of the Non-Breaching Party’s right to terminate extend beyond [**] days after the original cure period. 
 (b) Notwithstanding the foregoing provisions of this Section 13.3.1, if the applicable material breach is a material breach by EISAI of its obligations under Section 3.2 to use Commercially
Reasonable Efforts in one or more, but not all, of the United States, the Major EU Countries and Japan, then EPIZYME’s termination right pursuant to this Section 13.3.1 with respect to such breach shall be limited to a termination only in
the Major Market Country(ies) in which there was an uncured breach by EISAI with respect to the obligations of EISAI; provided that (i) if the diligence breach applies to two (but not all) of the United States, the Major EU
Countries or Japan, then this Agreement shall be terminated with respect to such Major Market Countries and the rest of the Territory, excluding the Major Market Country(ies) to which the diligence breach does not apply, and (ii) if the
diligence breach applies to all Major Market Country(ies), then this Agreement shall be terminated in its entirety. 
 (c) The
right of either Party to terminate this Agreement, or a portion of this Agreement, as provided in this Section 13.3.1 shall not be affected in any way by such Party’s waiver or failure to take action with respect to any previous material
breach. 
 13.3.2 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 14.1. The cure period for any allegation made in good faith as to a material breach under this
Agreement will, subject to Sections 13.3.1 and 14.2, run from the date that written notice was first provided to the Breaching Party by the Non-Breaching Party. 

  
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 13.4 Termination for EISAI Patent Challenge. If EISAI 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 Collaboration Patent owned by EPIZYME, 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 or any claim thereof (each activity under the foregoing clause (a) or (b), an “EISAI Patent Challenge”); 
 then
EPIZYME shall have the right to terminate this Agreement upon thirty (30) days’ written notice to EISAI. 
 13.5
Effects of Termination. 
 13.5.1 Termination by EISAI for Convenience or Safety; Termination by EPIZYME for Cause or
for Patent Challenge. If (w) this Agreement is terminated in its entirety as a result of EISAI’s uncured breach pursuant to Section 13.3.1, (x) EPIZYME terminates this Agreement as a result of an EISAI Patent Challenge
pursuant to Section 13.4, (y) EISAI terminates this Agreement in its entirety for convenience pursuant to Section 13.2.1(a) or EISAI terminates this Agreement in its entirety for safety concerns pursuant to Section 13.2.1(b), or
(z) this Agreement is terminated in its entirety pursuant to Section 13.2.3, then: 
 (a) License Termination.
All licenses granted to EISAI under Section 5.1.1 and all licenses granted to EPIZYME under Section 5.3.1 of this Agreement shall be terminated and of no further force and effect. 

(b) Summary of Activities. Within [**] days after such termination, EISAI shall provide to EPIZYME a fair and accurate summary
report of the status and results of its (and its Affiliates’ and Sublicensees’) Development and Commercialization activities for Licensed Compounds and Licensed Products prior to the effective date of termination in the Field in the
Territory. 
 (c) Transition Assistance. Without limiting the generality of the remainder of this Section 13.5.1,
EISAI shall use its Commercially Reasonable Efforts, at EPIZYME’s cost, to effect a seamless, timely transition to EPIZYME of all Development, Manufacturing and Commercialization activities and responsibilities for Licensed Compounds and
Licensed Products as they exist as of the date of termination in accordance with a transition plan to be mutually agreed by the Parties. 

  
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 (d) License Grant to EPIZYME. Effective upon such termination, EISAI hereby grants
to EPIZYME a perpetual, irrevocable, fully paid-up, exclusive license, with the right to grant sublicenses, under all EISAI IP, Collaboration IP, and Joint IP in each case Controlled by EISAI as of the effective date of termination and used as of
the effective date of termination in the Development, Manufacture or Commercialization of the Licensed Compound(s) and Licensed Product(s) as they exist as of the date of termination, solely to continue to Develop, Manufacture or Commercialize such
Licensed Compound(s) and Licensed Product(s) in the Field in the Territory; provided that: 
 (i) the foregoing
license shall exclude any license or other rights with respect to any therapeutically active pharmaceutical ingredient that is not a Licensed Compound and which is covered by Patents Controlled by EISAI or any of its Affiliates; 

(ii) EISAI shall provide EPIZYME with copies of any and all Third Party agreements with respect to the EISAI Patents and EISAI Know-How
that is the subject of the license granted by EISAI to EPIZYME pursuant to this Section 13.5.1(d) and EPIZYME may at any time thereafter exclude all of the EISAI Patents and EISAI Know-How that is the subject of any such Third Party agreement
from the grant set forth in this Section 13.5.1(d) by written notice to EISAI, in which event clause (iii) below shall not apply thereafter to such Third Party agreement and EPIZYME shall have no obligations with respect to any amounts
that may become payable under such Third Party agreement; 
 (iii) EPIZYME shall be responsible for (A) making any
payments (including royalties, milestones and other amounts) payable by EISAI to Third Parties under any such Third Party agreements that are applicable to the grant to EPIZYME of such license or to the exercise of such license by EPIZYME or any of
its Affiliates or sublicensees, by making such payments directly to EISAI and, in each instance, EPIZYME shall make the requisite payments to EISAI and provide the necessary reporting information to EISAI in sufficient time to enable EISAI to comply
with its obligations under such Third Party agreements, and (B) complying with any other obligations included in any such Third Party agreements that are applicable to the grant to EPIZYME of such license or to the exercise of such license by
EPIZYME or any of its Affiliates or sublicensees; and 
 (iv) EISAI shall be responsible for paying or providing to any such
Third Party any payments or reports made or provided by EPIZYME under this Section 13.5.1(d). 
 (e) Clinical
Development Activities. With respect to any clinical Development activities that are in progress at the time of notice of termination, (i) EPIZYME may elect, in its sole discretion, to complete such clinical Development activities, in which
event EISAI shall transfer to EPIZYME all such clinical Development activities as part of the transition plan to be mutually agreed by the Parties under clause (c) above, at EPIZYME’s expense, or (ii) if EPIZYME does not elect to
complete such clinical Development activities, EISAI shall promptly discontinue or wind-down, at EISAI’s cost, any such clinical Development activities, and forward all interim and final reports and underlying data from such activities to
EPIZYME. 

  
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 (f) Regulatory Filings. To the extent permitted by Law, EISAI will promptly assign
to EPIZYME all Regulatory Approvals, Regulatory Dossiers and Regulatory Materials for Licensed Products. If EISAI is restricted under Law from 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 13.5.1, including the conduct of clinical Development activities, if applicable, pursuant to Section 13.5.1(e) above), EISAI shall grant EPIZYME (or its designee) a right of
reference or use to such item (it being understood that EISAI shall use Commercially Reasonable Efforts to transfer the same to EPIZYME after the completion of such transition activities). EISAI shall take all actions reasonably necessary to effect
such transfer or grant of right of reference or use to EPIZYME, including by making such filings as may be required with Regulatory Authorities and other Governmental Authorities in the Territory that may be necessary to record such assignment or
effect such transfer. 
 (g) Marketing-Related Materials. Upon EPIZYME’s request, EISAI will promptly transfer and
deliver to EPIZYME all promotional materials used by EISAI as of the effective date of termination in the promotion of Licensed Products (and, for purposes of Section 13.5.2, in the Terminated Territory(ies)) (“Marketing-Related
Materials”) and effective on such termination EISAI hereby grants to EPIZYME a perpetual, irrevocable, fully paid-up, non-exclusive license, with the right to grant sublicenses, to reproduce, distribute, display, use, modify and exploit,
directly or indirectly, any such Marketing-Related Materials, in each case solely in connection with the exploitation of the Licensed Products; provided that neither EPIZYME nor any of its Affiliates or sublicensees shall have any right or
license to reproduce, distribute, display, use, modify or exploit any corporate name or logo of EISAI or its Affiliates on such materials. EPIZYME ACKNOWLEDGES AND AGREES THAT (A) EISAI MAKES NO REPRESENTATION OR WARRANTY OF ANY KIND, EXPRESS
OR IMPLIED, WITH RESPECT TO THE USE OF SUCH MATERIALS, INCLUDING ANY WARRANTY THAT THE MATERIALS ARE FIT FOR ANY PURPOSE OR THAT THE MATERIALS WILL NOT INFRINGE THE INTELLECTUAL PROPERTY RIGHTS OF ANY PERSON OR ENTITY, AND (B) NEITHER EISAI NOR
ITS AFFILIATES SHALL HAVE ANY LIABILITY OF ANY KIND TO EPIZYME, ITS AFFILIATES OR ANY THIRD PARTY RESULTING FROM OR IN CONNECTION WITH THE USE OF ANY SUCH MATERIALS BY ANY PERSON OR ENTITY. 

(h) Trademarks. If the First Commercial Sale of any Licensed Products has occurred as of the effective date of termination, at
EPIZYME’s request, EISAI shall assign to EPIZYME any EISAI trademark(s) used with respect to Licensed Products (other than EISAI’s company-specific names and company-specific logos) for use solely in connection with such Licensed Product.

 (i) Transfer of Data. Upon EPIZYME’s request, EISAI will promptly provide to EPIZYME copies of 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 EISAI as of the
effective date of termination and used as of the effective date of termination in the Development, Manufacture or Commercialization of the Licensed Products as they exist as of the effective date of termination. 

  
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 (j) Contracts. EISAI shall assign to EPIZYME, to the extent assignable and included
in the transition plan to be agreed by the Parties under clause (c) above, EISAI’s rights in any or all Third Party agreements for licenses, services or supplies used in connection with the Development, Manufacture or Commercialization of
Licensed Products, including any Third Party manufacturing agreements and clinical trial agreements (subject to clause (e) above), unless any such agreement covers Combination Products in which any active pharmaceutical ingredient that is not a
Licensed Compound is covered by Patents Controlled by EISAI or any of its Affiliates. In any manufacturing agreement relating to the Licensed Products, EISAI shall use Commercially Reasonable Efforts to require that the agreement be assignable to
EPIZYME upon termination of this Agreement. To the extent that any such agreement is not assignable by EISAI, then such agreement will not be assigned, and upon the request of EPIZYME, EISAI will cooperate in good faith and use Commercially
Reasonable Efforts to allow EPIZYME to obtain and to enjoy the benefits of such agreement in the form of a license or other right to the extent held by EISAI and subject to such Third Party’s rights. In addition, to the extent that any such
Third Party agreement is not specific to Licensed Products (and, for purposes of Section 13.5.2, Terminated Territory(ies)), and EISAI needs to retain such agreement for its own purposes unrelated to the applicable Licensed Products (and, for
purposes of Section 13.5.2, Terminated Territory(ies)), EISAI will cooperate in good faith and use Commercially Reasonable Efforts to allow EPIZYME to obtain and to enjoy the benefits of such agreement with respect to the applicable Licensed
Products (and, for purposes of Section 13.5.2, Terminated Territory(ies)) in the form of a sublicense, subcontract or other right, subject to such Third Party’s rights. 

(k) Manufacturing. Upon EPIZYME’s request, EISAI shall, as part of the transition plan to be mutually agreed by the Parties
under clause (c) above, at EPIZYME’s expense, transfer to EPIZYME (or its designee) any processes, documents, materials and other Know-How, to the extent the foregoing is Controlled by EISAI as of the effective date of termination and used
in the Manufacture of Licensed Products in the Field as they exist as of the date of termination; provided that, EISAI shall, upon EPIZYME’s request and pursuant to a supply agreement to be negotiated in good faith by the Parties,
at a purchase price equal to EISAI’s Cost of Goods plus [**] percent ([**]%), continue to supply EPIZYME with clinical and commercial quantities of such Licensed Product in the dosage strength, formulation and presentation under Development or
being Commercialized by EISAI, in either case, as of the effective date of termination, until the earlier of: (i) [**] months after the effective date of termination; or (ii) establishment by EPIZYME of an alternative supply for such
Licensed Product on commercially reasonable terms. 
 (l) Existing Inventory. At EPIZYME’s election, EISAI will
transfer to EPIZYME such portion of EISAI’s existing inventory of Licensed Products (including clinical trial materials and synthetic intermediates, if applicable) that EPIZYME elects and, with respect to any commercial supply, that is in good
and saleable condition, in its original, unopened packaging, at EISAI’s Cost of Goods for such Licensed Products. 
 (m)
Prosecution and Enforcement. The provisions of Article 9 shall be terminated, except Section 9.1. In addition, as between the Parties, EPIZYME shall have 

  
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the right (but not the obligation) to prosecute, maintain and enforce all EISAI Collaboration Patents that are primarily applicable to EZH2 or EZH2 Compounds and licensed to EPIZYME pursuant to
clause (d) above, under the same terms and to the same extent as EISAI had the right to prosecute, maintain and enforce the EPIZYME Collaboration Patents under Article 9 during the Term. EISAI shall provide such assistance and cooperation as
may be reasonably necessary in connection with the transition of prosecution and enforcement responsibilities to EPIZYME with respect to such EISAI Collaboration Patents, including execution of such documents as may be necessary to effect such
transition. 
 (n) Final Reconciliation; Joint Development and Commercialization Agreement. If EPIZYME had exercised its
Profit-Sharing Option with respect to any Shared Product(s), (i) the Parties shall also perform a final reconciliation of applicable Net Profits/Losses through the effective date of termination with respect to such Shared Product(s) as provided
in the applicable Joint Development and Commercialization Agreement, and (ii) except as set forth in the immediately preceding subsection (i) or as may otherwise be provided under the applicable Joint Development and Commercialization
Agreement, such Joint Development and Commercialization Agreement, and the Parties’ rights and obligations thereunder, shall terminate in its entirety. 
 Notwithstanding the foregoing provisions of this Section 13.5.1, if EISAI terminates this Agreement in accordance with Section 13.2.1(b) as a result of a bona fide serious safety issue regarding
the use of any Licensed Product that EISAI in good faith believes makes the continued Development or Commercialization of the Licensed Products unadvisable from a scientific, regulatory or ethical perspective, then the foregoing clauses
(c) through (m) of this Section 13.5.1 shall not apply; provided that EISAI, for itself and its Affiliates, hereby covenants and agrees not to assert any Patent rights Controlled by EISAI or its Affiliates against
EPIZYME or its Affiliates, or any of their successors, assigns, (sub)licensees, distributors, manufacturers or customers, with respect to the Manufacture, use, offer for sale, sale or importation of Licensed Compounds and Licensed Products.

 13.5.2 Termination of One or More, but Not All, Major Market Countries by EISAI for Convenience; Termination of One or
More, but Not All, Major Market Countries by EPIZYME for Cause. If (y) EPIZYME terminates this Agreement with respect to one or more, but not all, Major Market Countries as a result of EISAI’s uncured breach pursuant to
Section 13.3.1, or (z) EISAI terminates (or is deemed to terminate) this Agreement solely with respect to one or more, but not all, Major Market Countries for convenience pursuant to Section 13.2.1(a) (upon any termination under the
foregoing clause (y) or (z), each such terminated Major Market Country and, if two (but not all) Major Market Countries are terminated, the rest of the Territory (excluding the Major Market Country(ies) which is not terminated) shall be deemed
a “Terminated Territory”), then: 
 (a) Certain Effects of Termination. The effects of termination set
forth in 13.5.1(b) (Summary of Activities), 13.5.1(c) (Transition Assistance), 13.5.1(g) (Marketing-Related Materials), 13.5.1(h) (Trademarks), 13.5.(i) (Transfer of Data), 13.5.1(j) (Contracts), 13.5.1(k) (Manufacturing), 13.5.1(l) (Existing
Inventory) and 13.5.1(m) (Prosecution and Enforcement) above shall apply solely with respect to the Terminated Territory(ies). 

  
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 (b) Exclusion of Licenses. All rights and licenses granted by EPIZYME hereunder
(i) shall automatically be deemed to be amended to exclude, if applicable, the right to market, promote, detail, distribute, import, sell, offer for sale, file any NDA for, or seek any Regulatory Approval for Licensed Products in such
Terminated Territory(ies) and (ii) shall otherwise survive and continue in effect in such Terminated Territory(ies) solely for the purpose of furthering any Commercialization of the Licensed Products in the Territory or any Development in
support thereof. 
 (c) License Grant to EPIZYME. Effective upon such termination, EISAI hereby grants to EPIZYME a
perpetual, irrevocable, fully paid-up, exclusive license, with the right to grant sublicenses, under all EISAI IP, Collaboration IP, and Joint IP in each case Controlled by EISAI as of the effective date of termination and used as of the effective
date of termination in the Development, Manufacture or Commercialization of the Licensed Compound(s) and Licensed Product(s) as they exist as of the date of termination in such Terminated Territory(ies), solely to continue to Commercialize such
Licensed Compound(s) and Licensed Product(s) in the Field in such Terminated Territory(ies), to Develop such Licensed Compound(s) and Licensed Product(s) anywhere in the world in support of such Commercialization in such Terminated Territory(ies),
and to Manufacture such Licensed Compound(s) and Licensed Product(s) anywhere in the world in support of such Development or such Commercialization in such Terminated Territory(ies); provided that: 

(i) the foregoing license shall exclude any license or other rights with respect to any therapeutically active pharmaceutical ingredient
that is not a Licensed Compound and which is covered by Patents Controlled by EISAI or any of its Affiliates; 
 (ii) EISAI
shall provide EPIZYME with copies of any and all Third Party agreements with respect to the EISAI Patents and EISAI Know-How that is the subject of the license granted by EISAI to EPIZYME pursuant to this Section 13.5.2(c) and EPIZYME may at
any time thereafter exclude all of the EISAI Patents and EISAI Know-How that is the subject of any such Third Party agreement from the grant set forth in this Section 13.5.2(c) by written notice to EISAI, in which event clause (iii) below
shall not apply thereafter to such Third Party agreement and EPIZYME shall have no obligations with respect to any amounts that may become payable under such Third Party agreement; 

(iii) EPIZYME shall be responsible for (A) making any payments (including royalties, milestones and other amounts) payable by EISAI
to Third Parties under any such Third Party agreements that are applicable to the grant to EPIZYME of such license or to the exercise of such license by EPIZYME or any of its Affiliates or sublicensees, by making such payments directly to EISAI and,
in each instance, EPIZYME shall make the requisite payments to EISAI and provide the necessary reporting information to EISAI in sufficient time to enable EISAI to comply with its obligations under such Third Party agreements, and (B) complying
with any other obligations included in any such Third Party agreements that are applicable to the grant to EPIZYME of such license or to the exercise of such license by EPIZYME or any of its Affiliates or sublicensees; and 

  
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 (iv) EISAI shall be responsible for paying or providing to any such Third Party any
payments or reports made or provided by EPIZYME under this Section 13.5.2(c). 
 (d) Regulatory Filings. EISAI
shall: 
 (i) promptly assign to EPIZYME or, if such assignment is not permitted by Law, grant to EPIZYME a right of reference
or use to, Regulatory Approvals, Regulatory Dossiers and Regulatory Materials for Licensed Products in the Terminated Territory(ies) as they exist as of the date of termination and as they may be modified after the date of termination;
provided that EISAI retains a right of reference under any Regulatory Approvals, Regulatory Dossiers and Regulatory Materials transferred pursuant to this clause (i) as necessary or reasonably useful for EISAI to Commercialize
Licensed Products in the Territory, Develop Licensed Products in support of such Commercialization, or Manufacture Licensed Products in support of such Development or Commercialization; and 

(ii) to the extent necessary for EPIZYME to assume Development, Manufacture or Commercialization of Licensed Products in any Terminated
Territory(ies), (A) grant EPIZYME (or its designee) a right of reference or use to any and all Regulatory Approvals, Regulatory Dossiers and Regulatory Materials for Licensed Products related to any country(ies) or jurisdiction(s) of the
Territory with respect to which EISAI retains its licenses under this Agreement (i.e., country(ies) or jurisdiction(s) within the Territory other than the Terminated Territory(ies)) as such Regulatory Approvals, Regulatory Dossiers and
Regulatory Materials exist as of the date of termination; and (B) sign, and cause its Affiliates to sign, any instruments reasonably requested by EPIZYME in order to effect the grants contemplated in the foregoing subclause (A). 

(e) Final Reconciliation; Joint Development and Commercialization Agreement. If the Terminated Territory(ies) include the United
States, and if EPIZYME had exercised its Profit-Sharing Option with respect to any Shared Product(s), (i) the Parties shall also perform a final reconciliation of applicable Net Profits/Losses through the effective date of termination with
respect to such Shared Product(s) as provided in the applicable Joint Development and Commercialization Agreement, and (ii) except as set forth in the immediately preceding subsection (i) or as may otherwise be provided under the
applicable Joint Development and Commercialization Agreement, such Joint Development and Commercialization Agreement, and the Parties’ rights and obligations thereunder, shall terminate in its entirety. 

(f) Exclusivity. For the avoidance of doubt, the provisions of Section 8.1 shall not be deemed to be violated by the conduct
of any of the activities within the scope of the license granted to EPIZYME pursuant to Section 13.5.2(c) above. Notwithstanding anything in Section 8.1 to the contrary, the Parties’ exclusivity obligations under Section 8.1
shall terminate with respect to the Terminated Territory(ies) upon the latest of (i) the expiration of Patent-Based Exclusivity in such Terminated Territory(ies) with respect to all Licensed Product(s) existing as of the date of termination in
such Terminated Territory(ies); (ii) the expiration of Regulatory-Based Exclusivity in such Terminated Territory(ies) with respect to all Licensed Product(s) existing as of the date of termination in such Terminated Territory(ies), provided
that for 

  
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purposes of this Section 13.5.2(f) only, all references to EISAI in the definition of Regulatory-Based Exclusivity shall be deemed references to EISAI or EPIZYME; and (iii) the tenth
(10th) anniversary of the First Commercial Sale by either EISAI or EPIZYME in the Terminated Territory(ies) of a Licensed Product existing as of the date of termination in such Terminated Territory(ies), provided that for purposes of this
Section 13.5.2(f) only, all references to EISAI in the definition of First Commercial Sale shall be deemed references to EISAI or EPIZYME. 
 13.5.3 Termination by EISAI for Cause. If EISAI terminates this Agreement in its entirety pursuant to Section 13.3.1 as a result of EPIZYME’s uncured material breach, then: 

(a) the licenses granted under this Agreement to each Party shall be terminated and of no further force and effect; 

(b) if EPIZYME had exercised its Profit-Sharing Option, (i) the Parties shall also perform a final reconciliation of applicable Net
Profits/Losses through the effective date of termination with respect to such Shared Product(s) as provided in the applicable Joint Development and Commercialization Agreement, and (ii) except as set forth in the immediately preceding
subsection (i) or as may otherwise be provided under the applicable Joint Development and Commercialization Agreement, such Joint Development and Commercialization Agreement, and the Parties’ rights and obligations thereunder, shall
terminate in its entirety; 
 (c) the last sentence of Section 7.2.3 shall apply; and 

(d) EISAI shall have the right to pursue any remedies that may be available to it hereunder or at law. 

13.6 Accrued Rights; Surviving Provisions. 
 13.6.1 Termination 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 or expiration,
including the payment obligations under Article 7 hereof, and any and all damages or remedies arising from any breach hereunder. Such termination or expiration shall not relieve any Party from obligations which are expressly indicated to survive
termination of this Agreement. 
 13.6.2 The provisions of Sections 2.6.2, 5.4, 5.5, 9.1, 11.5, 13.1.2, 13.5, 13.6, and Articles
1 (to the extent definitions are required to interpret the surviving provisions of this Agreement), 7 (to the extent any amounts are due but unpaid as of the effective date of termination, to the extent provisions of Article 7 relate to payment
obligations that otherwise survive pursuant to Section 13.5 and Section 7.9 in accordance with its terms), 10, 12 and 14 shall survive the termination of this Agreement in its entirety or expiration of this Agreement, as applicable, in
accordance with their respective terms and conditions, and for the duration stated, and where no duration is stated, shall survive indefinitely. Article 10 shall survive for a period of [**] years after the effective date of termination or
expiration of this Agreement. 

  
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 ARTICLE 14 
 MISCELLANEOUS 
 14.1 Dispute Resolution. Except with respect to
disputes as to matters within the authority of the JSC, which shall be determined in accordance with Section 4.1.5 and which shall not be subject to this Section 14.1 (for purposes of clarity, neither shall such dispute be subject to
arbitration pursuant to Section 14.2), 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 Executive Officers are unable to resolve a given dispute pursuant to this Section 14.1 within [**] days after referring such dispute to the Executive Officers, either Party may have the
given dispute settled by binding arbitration pursuant to Section 14.2. 
 14.2 Arbitration Request. If a Party
intends to begin an arbitration to resolve a dispute arising under this Agreement, such Party shall provide written notice (the “Arbitration Request”) to the other Party of such intention and a statement of the issues for
resolution. From the date of the Arbitration Request and until such time as the 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 dispute. 
 14.2.1 Additional Issues. Within [**] days after the receipt of the
Arbitration Request, the other Party may, by written notice, add additional issues for resolution in a statement of counter-issues. 
 14.2.2 No Arbitration of Patent Issues. Any dispute, controversy or claim relating to the scope, validity, enforceability, infringement, inventorship or ownership of any Patents shall be submitted
to a court of competent jurisdiction in the country in which such patent rights apply. 
 14.2.3 Arbitration Procedure.
Any arbitration pursuant to this Article 14 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 Parties shall mutually agree on the rules to govern discovery and the rules of evidence for the arbitration within [**] days after the Arbitration Request. If the Parties
fail to timely agree to such rules, the United States Federal Rules of Civil Procedure will govern discovery and the United States Federal Rules of Evidence will govern evidence for the arbitration. The arbitration will be conducted by a single
arbitrator knowledgeable in the subject matter at issue in the dispute and acceptable to both Parties; provided that, the Parties may by mutual agreement elect to have the arbitration conducted by a panel of three (3) arbitrators.
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, within [**] days after the conclusion of the arbitration hearing, issue a written award and statement of decision describing the essential findings
and conclusions on which the award is based, including the calculation of any damages awarded. The arbitrator shall be limited in the scope of his or her authority to resolving only the specific matter which the Parties have referred to arbitration
for 

  
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resolution and shall not have authority to render any decision or award on any other issues. Subject to Section 12.5, the arbitrator shall be authorized to 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. The arbitrator also shall be authorized to 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 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. 

14.2.4 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. 
 14.2.5 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 dispute. 
 14.2.6 Confidentiality. All
proceedings and decisions of the arbitrator shall be deemed Confidential Information of each of the Parties, and shall be subject to Article 10. 
 14.3 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
excluding any conflicts or choice of law rule or principle that might otherwise refer construction or interpretation of this Agreement to the substantive law of another jurisdiction.. 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. 
 14.4 Assignment.
Neither Party may assign this Agreement without the consent of the other Party, except as otherwise provided in this Section 14.4. Either Party may assign this Agreement in whole or in part to any Affiliate of such Party without the consent of
the other Party; provided that, such assigning Party provides the other Party with written notice of such assignment, the Affiliate agrees in writing to assume performance of all assigned obligations, and the assigning Party shall
remain primarily liable for the performance of its obligations under this Agreement by such Affiliate. Further, subject to the remainder of this Section 14.4, each Party may assign this Agreement, and all of its rights and obligations
hereunder, without the consent of the other Party, to its successor in interest by way of merger or consolidation or in connection with the sale of all or substantially all of its business or assets to which this Agreement relates; provided
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. Any purported assignment in violation of this Section 14.4
shall be null and void. 

  
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 14.5 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. 

14.6 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 (other than a payment 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 EISAI, 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 EISAI 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. 
 14.7 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 personally delivered or sent by, facsimile transmission (receipt verified), or international 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.
		    	840 Memorial Drive
		    	Cambridge, Massachusetts 02139
		    	Attention: Chief Business Officer
		    	Telephone:  (617) 500-0712
		    	Facsimile: (617) 349-0707
		
	with a copy to:	    	WilmerHale LLP
		    	60 State Street
		    	Boston, MA 02109
		    	Attention: David E. Redlick, Esq.
		    	                 Steven D. Barrett, Esq.
		    	Telephone: (617) 526-6000
		    	Facsimile: (617) 526-5000

  
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	If to EISAI,	    	
		
	addressed to:	    	Eisai Co., Ltd.
		    	Koishikawa 4-6-10
		    	Bunkyo-Ku
		    	Tokyo 112-8088
		    	Japan
		    	Attention: Chief Product Creation Officer
		    	Telephone: 81-3-3817-5149
		    	Facsimile: 81-3-3811-1459
		
	with copies to:	    	Eisai Co., Ltd.
		    	Koishikawa 4-6-10
		    	Bunkyo-Ku
		    	Tokyo 112-8088
		    	Japan
		    	Attention: General Counsel
		    	Telephone: 81-3-3817-5089
		    	Facsimile: 81-3-3811-5535
		
	 and
	    	Eisai Inc.
		    	100 Tice Blvd.
		    	Woodcliff Lake, NJ 07677
		    	Attention: President
		    	                 General Counsel
		    	Telephone: (201) 746-2305
		    	Facsimile: (201) 746-3201

 or to such other address for such Party as it shall have specified by like notice to the other Party, provided
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 day on which such notice or request was given, or if such
day is not a Business Day, the first Business Day thereafter. If sent by overnight express courier service, the date of delivery shall be deemed to be the second Business Day after such notice or request was deposited with such service. 

14.8 Export Clause. Each Party acknowledges that the Laws of the United States restrict the export and re-export of certain
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. 
 14.9 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 

  
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waiver of such condition or term or of another condition or term. The rights and remedies provided herein are cumulative and do not exclude any other right or remedy provided by Law or otherwise
available except as expressly set forth herein. 
 14.10 Severability. If any provision hereof should be held invalid,
illegal or unenforceable in any jurisdiction or otherwise directly or indirectly affects the validity of any other material provision(s) of this Agreement (“Severed Clause”), all other provisions hereof shall remain in full force
and effect in such jurisdiction except for such Severed Clause, and such invalidity, illegality or unenforceability shall not affect the validity, legality or enforceability of such provision in any other jurisdiction. The Parties shall consult and
use good faith efforts to agree upon a valid and enforceable provision which shall be a reasonable substitute for such Severed Clause in light of the intent of this Agreement. 
 14.11 Entire Agreement. This Agreement and any Joint Development and Commercialization Agreement(s), together with the Exhibits hereto and thereto, set forth all the covenants, promises,
agreements, warranties, representations, conditions and understandings between the Parties with respect to the subject matter of this Agreement and supersede and terminate all prior agreements and understandings between the Parties with respect to
the subject matter of this Agreement. In 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. In the event of any conflict between the terms of this Agreement and any Joint Development and Commercialization Agreement, the terms of such Joint Development and Commercialization Agreement shall govern. 

14.12 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. 
 14.13 Non-solicitation of Key
Employees. During the period commencing on the Effective Date and ending upon the earlier of (a) the date of expiration, pursuant to Section 6.1.4, of the Profit-Sharing Option for the first Licensed Compound for which the
Profit-Sharing Option becomes available under Section 6.1, if EPIZYME does not exercise its Profit-Sharing Option with respect to such Licensed Compound, and (b) the date of First Commercial Sale of any Shared Product in the United States,
if EPIZYME exercises any Profit-Sharing Option, neither Party 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 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 14.13,
“Key Employee” means any employee who is material to the performance of the Collaboration hereunder, including any members of the JSC or any Subcommittee thereof. 

  
 - 79 -

 14.14 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 or Exhibit shall be deemed to be a reference to any Article, Section, subsection, paragraph, clause 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 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, (e) the word “or” is used in the inclusive sense (and/or) and (f) the singular shall include the plural, the plural the singular, the use of any
gender shall be applicable to all genders. 
 14.15 Books and Records. Any financial 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 customarily used by such Person in the applicable country (“GAAP”), consistently applied, except that
the same need not be audited. 
 14.16 Further Actions. Each Party 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. 
 14.17 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 the Parties hereto and their respective
successors and permitted assigns. The covenants and agreements set forth in this Agreement are for the sole benefit of the Parties and their successors, permitted assigns and, with respect to indemnification under Article 12, the indemnitees
identified thereunder, and they shall not be construed as conferring any rights on any other Persons. 
 14.18 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. 

  
 - 80 -

 14.19 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. 
 [Signature page to
follow] 

  
 - 81 -

 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
	
	Eisai Co., Ltd.
		
	By:	 	 /s/ Hideki Hayashi

	Name:	 	Hideki Hayashi
	Title:	 	Executive Vice President and Chief Product Creation Officer

  
 - 82 -

 EXHIBIT A 

Development Candidate Selection Criteria 
  

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

  
 A-1

 EXHIBIT B 

EPIZYME Patents 
 (as of the Effective Date) 
 I. Owned Patents 

 

																							
	 Origin
	  	Country	 	Title	 	Inventor List	 	Appl’n
Status	 	Serial
Number	 	Filing Date	 	Publication
Number	  	Publication
Date	  	Patent
Number	  	Issue Date	  	Expiration
Date
	 [**]
	  	[**]	 	[**]	 	[**]	 	[**]	 	[**]	 	[**]	 		  		  		  		  	
	 [**]
	  	[**]	 	[**]	 	[**]	 	[**]	 	[**]	 	[**]	 		  		  		  		  	
	 [**]
	  	[**]	 	[**]	 	[**]	 	[**]	 	[**]	 	[**]	 		  		  		  		  	
	 [**]
	  	[**]	 	[**]	 	[**]	 	[**]	 	[**]	 	[**]	 		  		  		  		  	
	 [**]
	  	[**]	 	[**]	 	[**]	 	[**]	 	[**]	 	[**]	 		  		  		  		  	
	 [**]
	  	[**]	 	[**]	 	[**]	 	[**]	 	[**]	 	[**]	 		  		  		  		  	

 II. In-Licensed Patents 
  

																							
	 Origin
	  	Country	 	Title	 	Inventor List	 	Appl’n
Status	 	Serial
Number	 	Filing Date	 	Publication
Number	 	Publication
Date	 	Patent
Number	 	Issue Date	 	Expiration
Date
	 [**]
	  	[**]	 	[**]	 	[**]	 	[**]	 	[**]	 	[**]	 	[**]	 	[**]	 	[**]	 	[**]	 	[**]
	 [**]
	  	[**]	 	[**]	 	[**]	 	[**]	 	[**]	 	[**]	 	[**]	 	[**]	 	[**]	 	[**]	 	[**]
	 [**]
	  	[**]	 	[**]	 	[**]	 	[**]	 	[**]	 	[**]	 	[**]	 	[**]	 	[**]	 	[**]	 	[**]
	 [**]
	  	[**]	 	[**]	 	[**]	 	[**]	 	[**]	 	[**]	 	[**]	 	[**]	 	[**]	 	[**]	 	[**]
	 [**]
	  	[**]	 	[**]	 	[**]	 	[**]	 	[**]	 	[**]	 	[**]	 	[**]	 	[**]	 	[**]	 	[**]
	 [**]
	  	[**]	 	[**]	 	[**]	 	[**]	 	[**]	 	[**]	 	[**]	 	[**]	 	[**]	 	[**]	 	[**]

  
 B-1

 EXHIBIT C 

Lead Candidate Criteria 
  

	 	•	 	 Confidential Materials omitted and filed separately with the Securities and Exchange Commission. A total of one page was omitted [**].

  
 C-1

 EXHIBIT D 

Initial Research and Development Plan 
 Table 1: EZH2 Program – Current Lead Series 
  

							
	 	  	Stage 1:
[**]	 	Stage 2:
[**]	 	Stage 3:
[**]
	 Target timing
	  	[**]	 	[**]	 	[**]
	 Responsible Party
	  	[**]	 	[**]	 	[**]
	 Key activities to milestone
	  	[**]	 	[**]	 	[**]
	 Overall cost to next milestone
	  	Epizyme FTEs: [**]
 External: $[**]
	 	Epizyme FTEs: [**]
 External: $[**]
	 	Epizyme FTEs: [**]
 External: $[**]

  

	4	 Breakdown of EZH2 costs to reach stage 1 

 Epizyme FTEs: [**] 
 External total: $[**] 

 

	5	 Breakdown of EZH2 cost to proceed from stage 1 to stage 2 

 Epizyme FTEs: [**] 
 External total: $[**] 

 

	6	 Breakdown of EZH2 cost to proceed from stage 2 to stage 3 

 Epizyme FTEs: [**] 
 External total: $[**] 

  
 D-1

									
	Stage 1 External Spend - $[**]	  				 			
			
	 Biological Sciences - $[**]
	  				 			
			
		  	 	[	**] 	 	 	[	**] 
			
		  	 	[	**] 	 	 	[	**] 
			
	 Biochem and Mol Pharm - $[**]
	  				 			
			
		  	 	[	**] 	 	 	[	**] 
			
	 Protein and Structural Sciences - $[**]
	  				 			
			
		  	 	[	**] 	 	 	[	**] 
			
	 Medicinal Chemistry - $[**]
	  				 			
			
		  	 	[	**] 	 	 	[	**] 
			
		  	 	[	**] 	 	 	[	**] 
			
		  	 	[	**] 	 	 	[	**] 
			
		  	 	[	**] 	 	 	[	**] 

  
 D-2

									
	 Stage 2 External Spend - $[**]
	  				 			
			
	 IND Enabling Studies - $[**]
	  				 			
			
		  	 	[	**] 	 	 	[	**] 
			
		  	 	[	**] 	 	 	[	**] 
			
		  	 	[	**] 	 	 	[	**] 
			
		  	 	[	**] 	 	 	[	**] 
			
		  	 	[	**] 	 	 	[	**] 
			
		  	 	[	**] 	 	 	[	**] 
			
		  	 	[	**] 	 	 	[	**] 
			
		  	 	[	**] 	 	 	[	**] 
			
	 In vivo pharmacology - $[**]
	  				 			
			
		  	 	[	**] 	 	 	[	**] 
			
	 Biomarker studies - $[**]
	  				 			
			
		  	 	[	**] 	 	 	[	**] 
			
	 Stage 3 External Spend - $[**]
	  				 			
			
	 API and Drug Product Manufacture - $[**]
	  				 			
			
		  	 	[	**] 	 	 	[	**] 
			
		  	 	[	**] 	 	 	[	**] 
			
	 Phase I clinical studies - $[**]
	  				 			
			
		  	 	[	**] 	 	 	[	**] 

  
 D-3

 EXHIBIT E 

Joint Development and Commercialization Agreement Term Sheet 
 All capitalized terms used but not otherwise defined in this Exhibit E will have the meanings ascribed to them in the Collaboration and License Agreement (the “CLA”). 

1. Parties. Epizyme, Inc. (“EPIZYME”) and Eisai Co., Ltd. or an Affiliate designated by Eisai Co., Ltd.
(“EISAI”). 
 2. Product and Indications: Shared Product for all Indications in the Field for which such Shared Product
is Developed or Commercialized in the U.S. The Parties will focus their Development and Commercialization efforts with respect to the Shared Product on particular Indication(s) as set forth in the Joint Development Plan and Joint Commercialization
Plan (each as defined below). 
 3. Territory: U.S. 
 4. Term: Profit-Share Term, unless earlier terminated in accordance with the CLA or the terms of an applicable Joint Development and Commercialization Agreement (the “JDCA”).

 5. Conduct of Joint Development and Commercialization: The Parties shall jointly Develop and Commercialize the Shared Product in the
U.S. in accordance with the Joint Development Plan and Joint Commercialization Plan and the terms of the JDCA, including, unless otherwise agreed by the Parties, the terms of this Exhibit E. 

6. Committees: 
 a)
Joint Steering Committee. The Parties shall establish a joint steering committee (the “JSC”) to perform the reconciliation of Net Profits/Losses, to oversee the Parties’ Development and Commercialization of Shared
Products for the United States, and to attempt to resolve disputes in the JDC and JMC (each as defined below). 
 b) Joint
Development Committee. The Parties shall establish a joint development committee (the “JDC”) to review and approve amendments to the Joint Development Plan and to monitor the Parties’ Development activities under the JDCA.

 c) Joint Marketing Committee. The Parties shall establish a joint marketing committee (the “JMC”) to
review and approve the initial Joint Commercialization Plan and all amendments thereto and to monitor the Parties’ Commercialization activities under the JDCA. 
 d) The terms with respect to membership, meetings, minutes, decision-making and subcommittees with respect to each of the JSC, JDC and JMC shall be substantially the same as those set forth in Article 4
of the CLA. 

  
 E-1

 7. Joint Development and Joint Commercialization Plans: 

a) Joint Development Plan. The Parties shall mutually agree upon the joint plan for Development of the Shared Product for the U.S.
(the “Joint Development Plan”) promptly following the applicable Notice of Exercise, which plan shall include the target Indications and patient populations, corresponding Development activities to be performed by each Party,
anticipated timelines, clinical supply forecasts, and the budget of Shared Development Costs. The Joint Development Plan may be amended or updated from time to time by mutual agreement of the Parties through the JDC, including any amendments or
updates to any anticipated timelines or to the then-current budget. 
 b) Joint Commercialization Plan. At an appropriate
time to be mutually agreed by the Parties through the JMC (but in any event [**] months prior to commercial launch of the applicable Shared Product in the United States), the Parties through the JMC shall mutually agree upon the initial joint plan
for Commercialization of such Shared Product for the U.S. (the “Joint Commercialization Plan”), with the goal that each Party’s participation in the Commercialization of Shared Product for the U.S. shall, to the extent
practicable, be substantially equal on an ongoing basis, provided that a Party shall not be assigned a particular Commercialization activity or responsibility unless it has the capacity and capability to undertake such activity or
responsibility, as determined by the JMC. The Joint Commercialization Plan may be amended or updated from time to time by mutual agreement of the Parties through the JMC, including any amendments or updates to any anticipated timelines or to the
then-current budget. The Joint Commercialization Plan shall encompass the planned Commercialization strategy in the U.S. for the applicable Shared Product and shall set forth the corresponding budget of Shared Commercialization Costs, anticipated
timelines, Commercialization activities to be performed by each Party, commercial supply forecasts, and the other matters described below. The initial Joint Commercialization Plan shall include the budgeted Shared Commercialization Costs for
pre-launch Commercialization activities in the U.S. and for Commercialization activities through at least [**] Calendar Years after the First Commercial Sale of the Shared Product in the U.S. Thereafter, the Joint Commercialization Plan shall be
updated by the Parties, through the JMC, on an [**] basis. The Joint Commercialization Plan shall contain at a minimum, solely in regards to the U.S., the following (unless otherwise mutually agreed by the Parties): 

(1) wholesale acquisition cost (“WAC”) pricing strategy, publication strategy (with the Parties to agree on roles and
responsibilities), market research and strategy, including market size, dynamics, growth, customer segmentation, competitive analysis and Shared Product positioning; 
 (2) sales forecast for the next [**] Calendar Years; 
 (3) medical education plan
which shall set forth medical science liaison (“MSL”) and medical affairs strategies and activities, including meetings with key opinion leaders, consultancy meetings or programs, non-promotional activities, conferences, budgets and
strategies for grant disbursements, medical information services, managing relationships with cooperative groups, and establishing and implementing risk, evaluation and mitigation strategies. 

  
 E-2

 (4) advertising and promotion programs and strategies, including sales literature,
promotional premiums, media plans, symposia and speaker programs; 
 (5) sales plans and activity, including sales force
training, and for each Party, development of appropriate sales training materials, and strategy and budget for samples; 
 (6)
post-marketing studies not required to obtain or maintain Regulatory Approvals to be conducted; 
 (7) the total Details required
to support the Shared Product, the responsibility for which Details shall be allocated 50/50 between the Parties (unless otherwise mutually agreed by the Parties), and the number of Sales Representatives and Details to be provided by each Party in
such period; 
 (8) the number of MSLs and medical affairs personnel and allocation between the Parties of MSL and medical
affairs coverage for the United States, the responsibility for which MSLs and medical affairs coverage shall be allocated 50/50 between the Parties (unless otherwise mutually agreed by the Parties), with the goal of having each Party participate on
a meaningful basis in such activities; 
 (9) the Party(ies) that is responsible for each Commercialization activity;
provided that, unless otherwise agreed by the Parties, the Parties shall jointly plan and participate in, and EISAI shall be solely responsible for administering, activities under the medical education plan with respect to meetings
with key opinion leaders, consultancy meetings or programs, conferences, grant disbursements, and medical information services (including responding to physician inquiries). 
 8. Responsibilities of the Parties Generally: Each Party shall use Commercially Reasonable Efforts to fulfill all responsibilities assigned to it under the Joint Development Plan and the Joint
Commercialization Plan and shall comply with the JDCA and all Laws. Neither Party shall be required to undertake specific activities with respect to the Development and Commercialization of the Shared Product for the U.S. unless such assigned
activities are set forth in a Joint Development Plan or Joint Commercialization Plan. 
 a) EPIZYME Responsibilities:

 i) EPIZYME shall undertake the responsibilities allocated to EPIZYME (A) in the Joint Development Plan under the
direction and oversight of the JDC and (B) in the Joint Commercialization Plan under the direction and oversight of the JMC; 
 ii) EPIZYME shall use (A) an appropriate management infrastructure to supervise the Sales Representatives, MSLs, medical affairs personnel and other

  
 E-3

 
appropriate functional groups (collectively, “Commercialization Personnel”) employed by EPIZYME and required to oversee performance of EPIZYME’s Commercialization
obligations under the Joint Commercialization Plan, including performance of its Detail Requirements, and (B) Commercialization Personnel of sufficient number and adequate experience to implement its responsibilities under the Joint
Commercialization Plan; and 
 iii) EPIZYME shall work together and coordinate with EISAI with respect to the preparation and
submission of regulatory applications, and obtaining and maintaining Regulatory Approvals, in the U.S. with respect to the Shared Product; provided that all such applications and Regulatory Approvals shall be owned by, and in the name of, EISAI.

 b) EISAI Responsibilities: 
 i) EISAI shall undertake the responsibilities allocated to EISAI (A) in the Joint Development Plan under the direction and oversight of the JDC and (B) in the Joint Commercialization Plan under
the direction and oversight of the JMC; 
 ii) Unless otherwise mutually agreed by the Parties, subject to JDC oversight,
(A) EISAI shall be responsible, in consultation with EPIZYME, for preparing and submitting regulatory applications to Regulatory Authorities in order to obtain the Regulatory Approvals with respect to the Shared Product, and EISAI shall own and
maintain all Regulatory Approvals, and (B) EISAI shall be responsible, in consultation with EPIZYME, for communicating and meeting with Regulatory Authorities with respect to the Shared Product, provided that (x) EISAI shall
share with EPIZYME material written communications it receives from Regulatory Authorities and (y) if EPIZYME so requests, and to the extent permitted by applicable Law, one (1) representative of EPIZYME shall have the right to be present
in any such communications and meetings with Regulatory Authorities; 
 iii) EISAI shall use (A) an appropriate management
infrastructure to supervise the Commercialization Personnel employed by EISAI and required to oversee performance of EISAI’s Commercialization obligations under the Joint Commercialization Plan, including performance of its Detail Requirements,
and (B) Commercialization Personnel of sufficient number and adequate experience to implement its responsibilities under the Joint Commercialization Plan; 
 iv) EISAI shall have the sole right and responsibility to (A) subject to the WAC pricing strategy adopted by the Parties in the Joint Commercialization Plan, determine the price and other terms of
sale for the Shared Product (including discounts, rebates, and the like) and (B) record and collect payment for sales of the Shared Product throughout the U.S. EISAI shall be responsible for distribution, invoicing and collection with respect
to sales of the Shared Product in the U.S. and shall book such sales (it being understood that EISAI shall be solely and exclusively responsible for its own revenue recognition with respect to the Shared Product, and EPIZYME shall have no
responsibility therefor); 

  
 E-4

 v) EISAI shall use Commercially Reasonable Efforts to build and maintain an appropriate
pharmacovigilance infrastructure, including to maintain a global safety database with respect to the Shared Product, in connection with which the Parties shall enter into a pharmacovigilance agreement; 

vi) EISAI shall have the sole right to Manufacture the Shared Product or contract a Third Party to Manufacture the Shared Product, in
either case, in a commercially reasonable manner, including managing raw material supply for Manufacturing the Shared Product, warehousing and distributing the Shared Product; 
 vii) EISAI will update the JMC on a [**] basis with respect to material Manufacturing matters for the Shared Product; and 
 viii) The Parties shall mutually agree upon the trademarks and logos to be used in connection with the Shared Product in the United States (the “Product Trademarks”), consistent with the
branding strategy implemented by EISAI with respect to such Shared Product in the ROW. Except as otherwise set forth in Section 13.5.1(h) or Section 13.5.2(a) of the CLA, EISAI shall have the sole right to register, maintain, enforce and
defend the Product Trademarks (excluding any EPIZYME company-specific names or company-specific logos) for the Shared Product and own such Product Trademarks (excluding any EPIZYME company-specific names or company-specific logos), including all
associated goodwill. For purposes of clarity, EPIZYME shall retain ownership of all right, title and interest in and to any EPIZYME company-specific names or company-specific logos, including all associated goodwill. 

9. Allocation and Reconciliation of Net Profits/Losses; Patent Enforcement Recoveries: 

a) Allocation: EISAI and EPIZYME shall each receive (in the case of profits) or pay (in the case of losses), as applicable, fifty
percent (50%) of Net Profit/Losses with respect to the Shared Product in the U.S., to be calculated and paid in accordance with the reporting, reconciliation and payment provisions of this Section 9. If any Shared Development Costs or
Shared Commercialization Costs are related both to the Shared Product in the U.S. and to other product(s) or territory(ies), only an equitable allocation of such costs shall be deemed Shared Development Costs or Shared Commercialization Costs,
respectively. 
 b) Third Party Payments: In accordance with Section 7.5.4 of the CLA, all milestone payments made to
UNC under Section 3.4 of the UNC License Agreement, and all royalty, milestone and other payments to a Third Party (other than UNC) made by either Party under Third Party agreements with respect to the Shared Product for the U.S. shall be
deemed Shared Commercialization Costs incurred by such Party and taken into account in determining Net Profits/Losses so that EISAI and EPIZYME shall share 

  
 E-5

 
equally in such Shared Commercialization Costs. Notwithstanding the foregoing, to the extent any royalty, milestone or other payments relating to a Shared Product in the U.S. are owed to a Third
Party as a result of a breach by either Party of any of its representations, warranties or obligations under the CLA or the JDCA, the breaching Party shall be solely responsible for such royalty, milestone or other payments and such royalty,
milestone or other payments shall not be included in calculating Net Profit/Losses. 
 c) Reconciliation of Net
Profits/Losses; Reporting Gross Revenues and Shared Expenses: The Parties shall conduct a quarterly reconciliation of Net Profits/Losses as follows: 
 i) Within [**] days after the end of each Calendar Quarter, each Party shall submit to the other Party a written report (the “Final Report”) setting forth (A) in the case of EISAI,
all sales in units and in value of Shared Product in the U.S. made by EISAI and its Affiliates during such Calendar Quarter and Cost of Goods for such Calendar Quarter, and (B) any Recoveries and the relevant Shared Development Costs, and
Shared Commercialization Costs incurred by such Party or its Affiliates with respect to the Shared Product in the U.S. during such Calendar Quarter, including a calculation showing as separate line items each component of Shared Development Costs
and Shared Commercialization Costs. 
 ii) Within [**] days after the exchange of reports set forth in clause (i) above, the
JSC shall, using the Final Reports prepared by each Party, prepare a reconciliation report for the Shared Product for such Calendar Quarter (the “Reconciliation Report”); provided, however, that if the
Parties’ representatives on the JSC are not able to agree on the Reconciliation Report within such [**]-day period, the Parties shall resolve the dispute in accordance with dispute resolution provisions substantially similar to those set forth
in Section 14.1 of the CLA. The Parties shall have audit rights substantially similar to those set forth in Section 7.9 of the CLA. The Reconciliation Report shall set forth, in reasonable detail: 

(1) a calculation of Net Profits/Losses, as applicable; and 
 (2) a statement of any amount of (“Reconciliation Payment”) owed by one Party to the other Party to achieve a 50/50 allocation of Net Profits/Losses for such Calendar Quarter. 

All reports under this Section 9 of this Exhibit E shall be considered Confidential Information of the submitting Party and
shall be subject to confidentiality obligations substantially similar to those in Article 10 of the CLA. 
 d) Payment.
Within [**] Business Days after delivery by the JSC of a Reconciliation Report to each Party (or the resolution of any dispute with respect thereto as set forth in clause (c)(ii) above), EISAI or EPIZYME, as the case may be, shall pay the
Reconciliation Payment to the other Party. 

  
 E-6

 e) Monthly Sales Data. EISAI shall provide EPIZYME, for EPIZYME’s informational
purposes, with unaudited monthly sales reports to the extent EISAI prepares such reports for its internal management purposes. 
 10. ROW
Development and Commercialization Costs. Except as otherwise provided below or in the CLA, EISAI shall be solely responsible for one hundred percent (100%) of all costs and expenses incurred to support Development, Manufacture and
Commercialization of the Shared Product during the applicable Profit-Share Term that is not allocated to the U.S. 
 a) If data
from a clinical study(ies) conducted in ROW is used in a substantive and material manner with respect to the Shared Product in the U.S., then the Parties shall discuss what percentage of the Development Costs for such clinical study(ies) will be
included in Shared Development Costs by taking into consideration the nature of such study(ies). 
 b) If data from a clinical
study(ies) conducted in the U.S. in connection with a Shared Product (where the costs for such study are included in Shared Development Costs) is used by EISAI, its Affiliates or Sublicensees in a substantive and material manner in any country or
countries outside of the U.S., then the Parties shall discuss as to whether or not EISAI will pay to EPIZYME any amount of the Shared Development Costs for such clinical study(ies) by taking into consideration the nature of such study(ies).

 11. Adverse Events; Recall; Product Liability Claims. 
 a) The Parties shall establish procedures for reporting adverse events and other Shared Product related safety issues. Unless otherwise agreed by the Parties, EISAI shall have the right and primary
responsibility to make decisions and to take immediate action with respect to Shared Product safety issues, including recalls, in all cases, after reasonable consultation with EPIZYME; provided, however, that EISAI may make such
decision without consultation with EPIZYME to the extent necessary for EISAI to comply with its regulatory obligations. 
 b) Any
Losses arising out of any Third Party Claim arising out of or resulting from the Development, Manufacture or Commercialization of any Shared Product for use or sale in the Field in the U.S. (“Product Liability Costs”), shall be
shared equally by the Parties as a Shared Commercialization Cost for purposes of calculating Net Profits/Losses, except to the extent such Losses arise out of any Third-Party Claim based on (a) a Party’s breach of any of its
representations, warranties, covenants or obligations pursuant to the CLA or the JDCA, or (b) the negligence or willful misconduct of a Party, its Affiliates, its or its Affiliates’ Sublicensees, or any of the respective officers,
directors, employees and agents of each of the foregoing entities, in the performance of obligations or exercise of rights under the CLA or the JDCA. 

  
 E-7

 12. Detailing Responsibilities. 

a) Generally. Detailing activities conducted by the Parties shall be conducted in accordance with the Joint Commercialization Plan
and as directed by the JMC. The Parties shall only use promotional materials, advertising materials and literature approved by the JMC (subject to appropriate legal, medical and regulatory review by the Parties). No Party shall be required to
undertake any activity under the JDCA which it believes, in good faith, would violate any Laws. The JMC shall determine and set forth in the Joint Commercialization Plan the targeted number of total Details to be performed by each Party during each
Calendar Year covered by the Joint Commercialization Plan, if any, (which Details shall be borne one-half by each Party unless otherwise mutually agreed) and the Target Audience for such Details (the “Detail Requirements”) in
accordance with the following principles: 
 i) The overall number of Details shall be set at a level mutually agreed by the
Parties through the JMC; 
 ii) EPIZYME shall in no event be assigned more than [**] percent ([**]%) of the Parties’ overall
Detailing responsibilities; 
 iii) Detailing responsibilities shall be allocated between the Parties in an equitable manner,
taking into consideration the capabilities and experience of each Party’s sales force, subject to the guiding principle that each Party will bear half of the Detailing responsibilities unless otherwise mutually agreed; 

iv) Detailing responsibilities shall be carried out in accordance with the applicable Joint Commercialization Plan and associated Shared
Commercialization Cost budget; and 
 v) Detail costs reimbursement shall be the same on an equivalent per-Detail basis for each
Party and shall be mutually agreed by the Parties through the JMC. 
 b) Detailing Reports. Each Party shall keep complete
and accurate records of all Details performed by its sales force with respect to the Shared Product in the U.S. Within [**] days following the end of each Calendar Quarter, each Party shall provide the JMC and the JSC with a report setting forth, in
such detail and form as the JSC shall require (the “Internal Detailing Report”), based upon each Party’s internal Detailing reporting system, the total number of Details actually performed by such Party, segmented by physician
specialty of the Target Audience during the immediately preceding Calendar Quarter. The Parties will, if reasonably necessary, cooperate through the JMC to establish compatible Detail reporting and tracking mechanisms for Detailing the Shared
Product to facilitate communication and coordination of the Detailing efforts between the Parties. 
 c) Failure to Perform
Detail Requirements. In the event that a Party believes that the other Party is not performing its Detail Requirements, then such Party may refer such matter to the JMC for resolution. 

  
 E-8

 13. Joint Marketing and Sales Meetings: The Parties shall plan and implement periodic joint sales and
marketing meetings, including a national launch meeting, for the Shared Product for the U.S. 
 14. Miscellaneous: 

a) Other Provisions. Subject to Section 6.1.1 of the CLA, the JDCA shall be based on this Exhibit E and contain
provisions regarding representations and warranties, indemnifications, termination rights, and other reasonable and customary provisions to be agreed by the Parties. 
 15. Definitions: 
 “Cost of Goods” shall mean EISAI’s
(or its Affiliates’) fully allocated costs of Manufacturing (or acquiring from a Third Party) Shared Product for Development or Commercialization in the U.S., without markup, determined in accordance with GAAP, consistently applied. For
purposes of this definition, “fully allocated costs” means direct and identifiable internal and external costs and charges consisting of the following: 
 (a) with respect to EISAI’s internal costs, “fully allocated costs” shall consist of the following direct costs and charges related to the Manufacturing of such Shared Product for
Development or Commercialization in the U.S.: (i) costs of active pharmaceutical ingredients, other raw materials and packaging components, plus inbound freight/transportation, duty, quality assurance (i.e., testing, documentation and
release of drug product), and other direct raw materials costs, (ii) labor costs directly involved with Manufacturing of Shared Product, (iii) manufacturing plant overhead charges reasonably allocable to the Shared Product, including
indirect labor and indirect expenses necessary to support Manufacturing of Shared Product and depreciation, purchase price variances and other manufacturing variances, utilities, manufacturing management and administration costs, general supplies,
transportation, warehouse equipment and IT, maintenance, repair and installation costs, costs of other plant services (waste treatment, waste incineration), ongoing stability program costs, technical services (process design and process
improvement), and security, in each case to the extent reasonably allocable to the Shared Product, and (iv) direct write-offs for inventory adjustments and losses due to expired, spoiled, damaged or otherwise unsaleable Shared Product (but
excluding costs due to negligence or willful misconduct of EISAI or its Affiliates); but excluding (w) costs and charges related to or occasioned by unused manufacturing capacity, (x) the manufacture of other products at EISAI’s
manufacturing facilities, (y) amortization of property, plant or equipment not reasonably related to Manufacturing of Shared Product for the U.S. market hereunder, and (z) allocation of general corporate overhead or other administrative
costs or expenses not directly or indirectly involved in the management of manufacturing, material procurement or product distribution for Shared Product for the U.S. market; and 

(b) with respect to EISAI’s external costs and charges, “fully allocated costs” shall consist of invoiced costs and
charges of suppliers of goods and services directly related to the Manufacture of Shared Product. 

  
 E-9

 “Detail” or “Detailing” shall mean, with respect to a
Shared Product, the communication by a Sales Representative to a member of the Target Audience (a) involving face-to-face contact, (b) describing in a fair and balanced manner the FDA-approved indicated uses and other relevant
characteristics of such Shared Product, (c) using promotional materials in an effort to increase the Target Audience prescribing or hospital ordering preferences of such Shared Product for its FDA-approved indicated uses, and (d) made at
the Target Audience member’s office, in a hospital or other place where the Target Audience member normally issues prescriptions where the principal objective is to place an emphasis, either primary or secondary, on a Shared Product and not
simply to discuss a Shared Product with a member of the Target Audience. For the avoidance of doubt, discussions at conventions, congresses and meetings of key opinion leaders organized by a Party shall not constitute “Details” or
“Detailing.” 
 “Net Profits/Losses” shall mean (a) Net Sales of the Shared Product in the U.S.,
plus (b) Recoveries (if any), less Shared Development Costs, Cost of Goods and Shared Commercialization Costs. For the avoidance of doubt, (1) costs deducted in calculating Net Sales shall not be deducted a second time in
calculating Net Profits/Losses, and (2) costs that are included in one category of costs (i.e., Shared Development Costs) shall not be deducted a second time in calculating any other costs (i.e., Cost of Goods) that are deducted
in calculating Net Profits/Losses. 
 “Out-of-Pocket Costs” shall mean, with respect to Development or
Commercialization Activities performed under the JDCA, out-of-pocket expenses of each Party and its Affiliates in each case that are specifically associated with the conduct of such activities, including costs of consultants, agents and
subcontractors, recorded in accordance with GAAP. 
 “Recoveries” shall mean all cash amounts (plus the fair
market value of all non-cash consideration) received by a Party from a Third Party solely in connection with the judgment, award or settlement of any enforcement of intellectual property Controlled by EISAI, EPIZYME or the Parties jointly, in each
case Covering the Shared Product in a Competitive Infringement in the U.S. 
 “Sales Representative” shall mean
a professional pharmaceutical sales representative employed by either Party to conduct primarily Detailing and other promotional efforts with respect to a Shared Product and who has been trained by either Party in accordance with a training protocol
to be agreed upon by the Parties as set forth in the Joint Commercialization Plan. 
 “Shared Commercialization
Costs” shall mean all Out-of-Pocket Costs incurred by a Party with respect to Commercialization of the Shared Product allocated for the U.S. (pursuant to Section 9(a)) in accordance with the Joint Commercialization Plan, including:

 a) costs for launch, promotion, advertising, distribution, recalls, marketing (including telemarketing), MSL, medical affairs
and other medical education activities (consumer and professional), advocate development programs and symposia, sales meetings, samples, product related public relations, market research, health economics studies, post-marketing studies not required
to obtain or maintain Regulatory Approvals, relationships with opinion leaders and professional societies, training (including any 

  
 E-10

 
Shared Product training), market research, sales and marketing data, marketing communications, adverse events reporting, product hotlines, providing product to and administering indigent
programs, monitoring the sales and medical affairs of the Shared Product, and activities related to obtaining reimbursement from payers and other costs incurred collecting fees for Shared Product. 

b) Detailing cost as determined in accordance with Section 12 of this Exhibit E; 

c) costs for Prosecuting and Maintaining Patents that Cover the Shared Product in the U.S. in accordance with Section 9.2 of the CLA;

 d) costs of enforcement of Patents that Cover the Shared Product in any Competitive Infringement in the U.S. in accordance
with Section 9.5 of the CLA; 
 e) costs associated with selecting, filing, prosecuting, maintaining, defending and
enforcing Product Trademarks for the Shared Product in the U.S.; 
 f) Subject to Section 11 above, Product Liability Costs
and costs of recalls with respect to the Shared Product in the U.S.; 
 g) milestone payments to UNC pursuant to Section 3.4
of the UNC License Agreement; 
 h) Subject to Section 9(b) above, payments to Third Parties (other than UNC) under licenses
from such Third Parties for patents Covering the sale or Commercialization of the Shared Product in the U.S., including upfront, milestone, and royalty payments to such Third Parties; provided, however, that, to the extent that
any such Third Party license includes a license to Third Party intellectual property that is applicable to products being or to be developed or commercialized by such Party or its Affiliates other than such Shared Product in the U.S., then such
Party shall reasonably allocate all upfront payments, milestone payments and other non-royalty amounts between the Shared Product and such other products, and such Party shall only be entitled to include in Shared Commercialization Costs hereunder
the amounts that are reasonably allocable to the Shared Product for the U.S.; and 
 i) such other costs as the Parties may
agree. 
 Shared Commercialization Costs will specifically exclude (a) all costs with respect to a Party’s or its
Affiliate’s employees that perform Commercialization activities, other than Detailing cost as determined in accordance with Section 12 of this Exhibit E and (b) the cost of activities that promote either Party’s business
as a whole without being specific to the Shared Product (such as corporate image advertising). 
 “Shared Development
Costs” shall mean the following Out-of-Pocket Costs incurred by a Party with respect to Development of the Shared Product for the U.S. market (pursuant to Section 9(a) and Section 10) in accordance with the Joint Development Plan:

 a) Out-of-Pocket Costs that are attributable to the Development of the Shared Product for the U.S. market including:

 i) Clinical studies, including post-marketing commitments and all activities associated with starting, maintaining, and
closing studies; 

  
 E-11

 ii) Consultants used to obtain, maintain, or expand the Regulatory Approval of the Shared
Product; 
 iii) Regulatory filing fees; 
 iv) Costs associated with chemical, formulation or process development activities relating to the Shared Product, including conformance or qualification lots, process improvements, scale-up and
manufacturing facility transfers; 
 v) Test method development, stability testing, report writing and ongoing quality
assurance/quality control activities; 
 vi) Costs to prepare, submit, or develop data or information for submission to a
Regulatory Authority to obtain, maintain, or expand Regulatory Approval of the Shared Product (pre- or post-launch); 
 vii)
milestone payments made to UNC pursuant to Section 3.4 of the UNC License Agreement; 
 viii) Subject to Section 9(b)
above, payments to Third Parties (other than UNC) under licenses from such Third Parties for patents Covering the Development of the Shared Product for the U.S., including upfront, milestone, and royalty payments to such Third Parties;
provided, however, that, to the extent that any such Third Party license includes a license to Third Party intellectual property that is applicable to products being or to be developed or commercialized by such Party or its
Affiliates other than such Shared Product in the U.S., then such Party shall reasonably allocate all upfront payments, milestone payments and other non-royalty amounts between the Shared Product and such other products, and such Party shall only be
entitled to include in Shared Development Costs hereunder the amounts that are reasonably allocable to the Shared Product for the U.S.; and 
 ix) Other payments to Third Parties for the performance of any Development activities with respect to the Development of the Shared Product in accordance with the Joint Development Plan or otherwise
agreed upon by the Parties. 
 Shared Development Costs will specifically exclude all costs with respect to a Party’s or its
Affiliate’s employees that perform Development activities. 
 “Target Audience” shall mean the physicians
or other health care professionals with authority to prescribe a pharmaceutical product or issue hospital orders for a pharmaceutical product in the U.S. 

  
 E-12

 EXHIBIT F 

Press Release 
 Epizyme Enters Worldwide Strategic Partnership with Eisai for Cancer 

Therapeutics Targeting EZH2 Epigenetic Enzyme 
 -Agreement Includes US Profit Share and Co-Promotion Option for Epizyme- 
 Cambridge,
MA, March 10, 2011 - Epizyme, Inc. announced today a worldwide partnership with Eisai Co., Ltd., Tokyo, Japan to discover, develop and commercialize therapeutics targeting EZH2, an epigenetic enzyme, for the treatment of lymphoma and other
cancers in genetically-defined patients. Under the terms of the agreement, Epizyme will receive $6M in upfront and initial milestone payments, and may earn more than $200M in additional research, development and sales milestones, and up to
double-digit royalties. Additionally, Eisai will fund 100 percent of R&D through human proof-of-concept, at which point Epizyme has the right to opt into a profit share and co-commercialization arrangement for the United States. 

“Eisai is committed to bringing epigenetic therapeutics to cancer patients,” said Takashi Owa, Ph.D., President, Oncology Product Creation
Unit, Eisai Product Creation Systems. “Epizyme’s proprietary product platform; leadership in determining the oncogenic role of EZH2 in genetically-defined cancers; and success in discovering novel, potent, and selective small molecule
inhibitors of histone methyltransferases (HMTs), an important epigenetic target class, led us to them as the partner of choice in epigenetic drug discovery.” 
 “Our partnership with Eisai reflects our shared belief in the therapeutic potential of this area and is an important element in the ongoing execution of our strategy to build a leading new biopharma
company by bringing innovative personalized therapeutics to genetically-defined cancer patients,” commented Robert Gould, Ph.D., President and CEO of Epizyme. “The US profit share and co-commercialization option is a key element of our
strategy to discover, develop and also to commercialize epigenetic medicines.” 
 About Epizyme 

Epizyme is leading the discovery and development of small molecule histone methyltransferase (HMT) inhibitors, a new class of targeted therapeutics for
the treatment of genetically-defined cancer patients based on breakthroughs in the field of epigenetics. Genetic alterations in the HMTs are strongly associated with the underlying causes of multiple human diseases, including cancer. Epizyme’s
patient-driven approach represents the future of personalized therapeutics by creating better medicines for the right patients more quickly and at lower cost than traditional approaches. www.epizyme.com 

About Eisai Co., Ltd. 
 Eisai Co., Ltd.
is a research-based human health care (hhc) company that discovers, develops and markets products throughout the world. Through a global network of research facilities, manufacturing sites and marketing subsidiaries, Eisai actively
participates in all aspects of the worldwide healthcare system. www.eisai.com 
 Media Contacts 

Epizyme: 
 Chris Erdman or 

Jennifer Conrad 
 MacDougall Biomedical
Communications 
 781.235.3060 

Eisai: 
 Media Inquiries: Suzanne Grogan,
suzanne_grogan@eisai.com, 201-746-2083 
 Investor Inquiries: Alex Scott, 201-746-2177 

  
 F-1

 EXHIBIT G 

Licensed Compounds 
 (as of the Effective Date) 
  

					
	 Compounds in Current Lead
 Series (including but not
 limited to the
following)
	 	 EZH@ Potency (nM)
	 	 Fold Selectivity relative to

HMT with smallest selectivity
 window (excluding EZHi)

	 EPZ006087
	 	[**]	 	[**]
	 EPZ005996
	 	[**]	 	[**]
	 EPZ006110
	 	[**]	 	[**]
	 EPZ006177
	 	[**]	 	[**]
	 EPZ006122
	 	[**]	 	[**]
	 EPZ006127
	 	[**]	 	[**]
	 EPZ006051
	 	[**]	 	[**]
	 EPZ006052
	 	[**]	 	[**]
	 EPZ006125
	 	[**]	 	[**]
	 EPZ006093
	 	[**]	 	[**]
	 EPZ006179
	 	[**]	 	[**]
	 EPZ006124
	 	[**]	 	[**]
	 EPZ006053
	 	[**]	 	[**]
	 EPZ006092
	 	[**]	 	[**]
	 EPZ006173
	 	[**]	 	[**]
	 EPZ006090
	 	[**]	 	[**]

 [**]. 
 [**]

  
 G-1EX-10.18

 Exhibit 10.18 
 Confidential Materials omitted and filed separately with the Securities and Exchange Commision. Double asterisks denote omissions. 
 EXECUTION VERSION 
 COLLABORATION AND LICENSE AGREEMENT 

among 

CELGENE INTERNATIONAL SÀRL, 
 CELGENE CORPORATION 
 and 

EPIZYME, INC. 
 CONFIDENTIAL 

 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”	  	 	3	  
	 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 IP”	  	 	3	  
	 1.14
	    	“CELGENE Patent(s)”	  	 	4	  
	 1.15
	    	“CELGENE Provided Compound”	  	 	4	  
	 1.16
	    	“CELGENE Provided Compound IP”	  	 	4	  
	 1.17
	    	“CELGENE Provided Compound Patents”	  	 	4	  
	 1.18
	    	“CELGENE Territory”	  	 	4	  
	 1.19
	    	“cGMP”	  	 	4	  
	 1.20
	    	“Chemistry IP”	  	 	4	  
	 1.21
	    	“Clinical Trial”	  	 	4	  
	 1.22
	    	“CMC”	  	 	4	  
	 1.23
	    	“Collaboration IP”	  	 	5	  
	 1.24
	    	“Commercialization”	  	 	5	  
	 1.25
	    	“Commercially Reasonable Efforts”	  	 	5	  
	 1.26
	    	“Comparable Third Party Product”	  	 	6	  
	 1.27
	    	“Comparable Third Party Product Competition”	  	 	6	  
	 1.28
	    	“Compound(s)”	  	 	6	  
	 1.29
	    	“Control”, “Controls” or “Controlled”	  	 	6	  
	 1.30
	    	“Cover”, “Covering” or “Covered”	  	 	6	  
	 1.31
	    	“Develop” or “Development”	  	 	7	  
	 1.32
	    	“Development Candidate”	  	 	7	  
	 1.33
	    	“Development Candidate Selection Criteria”	  	 	7	  
	 1.34
	    	“Development Costs”	  	 	7	  
	 1.35
	    	“Development Plan”	  	 	7	  
	 1.36
	    	“Development Program”	  	 	7	  
	 1.37
	    	“Development Term”	  	 	7	  
	 1.38
	    	“Diagnostic Product”	  	 	8	  
	 1.39
	    	“Directed”	  	 	8	  
	 1.40
	    	“Dollars” or “$”	  	 	8	  
	 1.41
	    	“DOT1L”	  	 	8	  

  
 - i -

							
	 1.42
	    	“DOT1L Compound(s)”	  	 	8	  
	 1.43
	    	“DOT1L Phase 1 Costs”	  	 	8	  
	 1.44
	    	“EMA”	  	 	8	  
	 1.45
	    	“EPIZYME Background Chemistry IP”	  	 	8	  
	 1.46
	    	“EPIZYME Background IP”	  	 	8	  
	 1.47
	    	“EPIZYME Collaboration IP”	  	 	9	  
	 1.48
	    	“EPIZYME IP”	  	 	9	  
	 1.49
	    	“EPIZYME Patent(s)”	  	 	9	  
	 1.50
	    	“EPIZYME Reserved Targets”	  	 	9	  
	 1.51
	    	“EPIZYME Territory”	  	 	9	  
	 1.52
	    	“EPZ5676”	  	 	9	  
	 1.53
	    	“EU”	  	 	9	  
	 1.54
	    	“Executive Officers”	  	 	9	  
	 1.55
	    	“[**]”	  	 	9	  
	 1.56
	    	“FDA”	  	 	9	  
	 1.57
	    	“Field”	  	 	9	  
	 1.58
	    	“First Commercial Sale”	  	 	9	  
	 1.59
	    	“Global Development Costs”	  	 	10	  
	 1.60
	    	“GLP”	  	 	10	  
	 1.61
	    	“GSK”	  	 	10	  
	 1.62
	    	“GSK Agreement”	  	 	10	  
	 1.63
	    	“HSR Act”	  	 	10	  
	 1.64
	    	“IND”	  	 	10	  
	 1.65
	    	“Indication”	  	 	10	  
	 1.66
	    	“Initiation”	  	 	10	  
	 1.67
	    	“Joint Collaboration Chemistry IP”	  	 	10	  
	 1.68
	    	“Joint Collaboration IP”	  	 	11	  
	 1.69
	    	“Joint Collaboration Non-Chemistry IP”	  	 	11	  
	 1.70
	    	“Know-How”	  	 	11	  
	 1.71
	    	“Law” or “Laws”	  	 	11	  
	 1.72
	    	“Lead Candidate”	  	 	11	  
	 1.73
	    	“Lead Candidate Criteria”	  	 	11	  
	 1.74
	    	“Lead Candidate Product”	  	 	11	  
	 1.75
	    	“Legal Exclusivity”	  	 	12	  
	 1.76
	    	“License Event”	  	 	12	  
	 1.77
	    	“Licensed Compound(s)”	  	 	12	  
	 1.78
	    	“Licensed Product(s)”	  	 	13	  
	 1.79
	    	“MAA”	  	 	13	  
	 1.80
	    	“Major EU Country”	  	 	13	  
	 1.81
	    	“Manufacture” or “Manufacturing”	  	 	13	  
	 1.82
	    	“MHLW”	  	 	13	  
	 1.83
	    	“NDA”	  	 	13	  
	 1.84
	    	“Net Sales”	  	 	13	  
	 1.85
	    	“[**]”	  	 	13	  
	 1.86
	    	“Out-of-Pocket Costs”	  	 	13	  
	 1.87
	    	“Patent”	  	 	13	  

  
 - ii -

							
	 1.88
	    	“Patent-Based Exclusivity”	  	 	13	  
	 1.89
	    	“Person”	  	 	15	  
	 1.90
	    	“Phase 1 Clinical Trial”	  	 	15	  
	 1.91
	    	“Phase 2 Clinical Trial”	  	 	15	  
	 1.92
	    	“Phase 3 Clinical Trial”	  	 	16	  
	 1.93
	    	“Pivotal Clinical Trial”	  	 	16	  
	 1.94
	    	“Product Liability”	  	 	16	  
	 1.95
	    	“Proof of Concept”	  	 	16	  
	 1.96
	    	“Prosecution and Maintenance” or “Prosecute and Maintain”	  	 	16	  
	 1.97
	    	“Regulatory Approval”	  	 	16	  
	 1.98
	    	“Regulatory Authority”	  	 	17	  
	 1.99
	    	“Regulatory-Based Exclusivity”	  	 	17	  
	 1.100
	    	“Regulatory Materials”	  	 	17	  
	 1.101
	    	“Related Compound”	  	 	17	  
	 1.102
	    	“Research Plan”	  	 	17	  
	 1.103
	    	“Selection Term”	  	 	17	  
	 1.104
	    	“Stock Purchase Agreement”	  	 	18	  
	 1.105
	    	“Sublicensee”	  	 	18	  
	 1.106
	    	“Target”	  	 	18	  
	 1.107
	    	“Territory-Specific Development Costs”	  	 	18	  
	 1.108
	    	“Third Party”	  	 	18	  
	 1.109
	    	“United States” or “U.S.”	  	 	19	  
	 1.110
	    	“Valid Claim”	  	 	19	  
	 1.111
	    	Additional Definitions	  	 	19	  
	 ARTICLE 2 COLLABORATION; RESEARCH PLAN; TARGET SELECTION
	  	 	23	  
	 2.1
	    	Collaboration Overview	  	 	23	  
	 2.2
	    	Research Plan; Research Activities	  	 	23	  
	 2.3
	    	Targets	  	 	25	  
	 2.4
	    	Celgene Option; Target Selection	  	 	26	  
	 2.5
	    	Reports; Results	  	 	27	  
	 2.6
	    	Subcontracting	  	 	27	  
	 2.7
	    	Regulatory Matters; Compliance	  	 	28	  
	 ARTICLE 3 DEVELOPMENT AND COMMERCIALIZATION
	  	 	34	  
	 3.1
	    	Development Plans	  	 	34	  
	 3.2
	    	Development Activities	  	 	34	  
	 3.3
	    	Proof of Concept Determination	  	 	35	  
	 3.4
	    	Reports	  	 	35	  
	 3.5
	    	Commercialization	  	 	36	  
	 3.6
	    	Diligence	  	 	36	  
	 3.7
	    	No Representation	  	 	36	  
	 3.8
	    	EPIZYME Opt-Out	  	 	37	  
	 ARTICLE 4 GOVERNANCE
	  	 	43	  
	 4.1
	    	Joint Research Committee	  	 	43	  

  
 - iii -

							
	 4.2
	    	Joint Development Committee	  	 	45	  
	 4.3
	    	Joint Commercialization Committee	  	 	47	  
	 4.4
	    	Procedures of the JRC, JDC and JCC	  	 	49	  
	 4.5
	    	Patent Committee	  	 	51	  
	 4.6
	    	Alliance Managers	  	 	54	  
	 4.7
	    	Assigned Activities	  	 	54	  
	 ARTICLE 5 LICENSE GRANTS
	  	 	54	  
	 5.1
	    	License Grants To CELGENE	  	 	54	  
	 5.2
	    	License Grants to EPIZYME	  	 	56	  
	 5.3
	    	Licenses to CELGENE Lead Candidates	  	 	59	  
	 5.4
	    	Rights Retained by the Parties	  	 	60	  
	 5.5
	    	Section 365(n) of the Bankruptcy Code	  	 	60	  
	 5.6
	    	Technical Transfer and Disclosure of Know-How	  	 	60	  
	 ARTICLE 6 FINANCIAL TERMS
	  	 	60	  
	 6.1
	    	Upfront Fee	  	 	60	  
	 6.2
	    	Purchase of Shares	  	 	61	  
	 6.3
	    	Celgene Option Extension Fee	  	 	61	  
	 6.4
	    	Research Funding During the Selection Term	  	 	61	  
	 6.5
	    	Development Funding	  	 	61	  
	 6.6
	    	Territory-Specific Development Costs	  	 	62	  
	 6.7
	    	Milestones	  	 	63	  
	 6.8
	    	Royalties	  	 	65	  
	 6.9
	    	[**]	  	 	70	  
	 6.10
	    	Reports; Royalty Payments	  	 	70	  
	 6.11
	    	Methods of Payments; Payments Non-Refundable and Non-Creditable	  	 	70	  
	 6.12
	    	Accounting	  	 	70	  
	 6.13
	    	Taxes	  	 	71	  
	 6.14
	    	Late Payments	  	 	72	  
	 ARTICLE 7 EXCLUSIVITY; RIGHT OF FIRST NEGOTIATION; STANDSTILL
	  	 	72	  
	 7.1
	    	Selected Target Exclusivity	  	 	72	  
	 7.2
	    	Right of First Negotiation	  	 	75	  
	 ARTICLE 8 OWNERSHIP OF INTELLECTUAL PROPERTY RIGHTS
	  	 	76	  
	 8.1
	    	Ownership	  	 	76	  
	 8.2
	    	Prosecution and Maintenance of Patents	  	 	78	  
	 8.3
	    	Patent Costs	  	 	80	  
	 8.4
	    	Defense of Claims Brought by Third Parties	  	 	80	  
	 8.5
	    	Enforcement of EPIZYME Patents and CELGENE Patents	  	 	80	  
	 8.6
	    	Regulatory Data Protection	  	 	82	  
	 8.7
	    	Patent Term Extensions	  	 	82	  
	 8.8
	    	Common Interest Disclosures	  	 	83	  

  
 - iv -

							
	 ARTICLE 9 CONFIDENTIALITY
	  	 	83	  
	 9.1
	    	Confidentiality; Exceptions	  	 	83	  
	 9.2
	    	Authorized Disclosure	  	 	84	  
	 9.3
	    	Press Release; Disclosure of Agreement	  	 	85	  
	 9.4
	    	Prior Disclosures of Confidential Information	  	 	88	  
	 9.5
	    	Remedies	  	 	88	  
	 9.6
	    	Publications	  	 	88	  
	 9.7
	    	Clinical Trial Register	  	 	90	  
	 ARTICLE 10 REPRESENTATIONS AND WARRANTIES
	  	 	90	  
	 10.1
	    	Representations and Warranties of Both Parties	  	 	90	  
	 10.2
	    	Representations and Warranties of EPIZYME	  	 	91	  
	 10.3
	    	Representations and Warranties of CELGENE	  	 	92	  
	 10.4
	    	Mutual Covenants	  	 	93	  
	 10.5
	    	Disclaimer	  	 	94	  
	 ARTICLE 11 INDEMNIFICATION; INSURANCE
	  	 	94	  
	 11.1
	    	Indemnification by CELGENE	  	 	94	  
	 11.2
	    	Indemnification by EPIZYME	  	 	95	  
	 11.3
	    	Procedure and Conditions to Indemnification	  	 	96	  
	 11.4
	    	LIMITATION OF LIABILITY	  	 	98	  
	 ARTICLE 12 TERM AND TERMINATION
	  	 	99	  
	 12.1
	    	Term; Expiration	  	 	99	  
	 12.2
	    	Unilateral Termination by CELGENE	  	 	100	  
	 12.3
	    	Termination for Cause	  	 	100	  
	 12.4
	    	Termination for Patent Challenges	  	 	103	  
	 12.5
	    	Termination for Bankruptcy	  	 	105	  
	 12.6
	    	Effects of Termination	  	 	105	  
	 12.7
	    	Accrued Rights; Surviving Provisions; Right to Set-off	  	 	111	  
	 ARTICLE 13 MISCELLANEOUS
	  	 	112	  
	 13.1
	    	Dispute Resolution	  	 	112	  
	 13.2
	    	Baseball Arbitration	  	 	112	  
	 13.3
	    	Venue; Jurisdiction	  	 	114	  
	 13.4
	    	Governing Law	  	 	114	  
	 13.5
	    	Assignment	  	 	114	  
	 13.6
	    	Performance Warranty	  	 	115	  
	 13.7
	    	Force Majeure	  	 	115	  
	 13.8
	    	Notices	  	 	115	  
	 13.9
	    	Export Clause	  	 	116	  
	 13.10
	    	Waiver	  	 	116	  
	 13.11
	    	Severability	  	 	117	  
	 13.12
	    	Entire Agreement	  	 	117	  
	 13.13
	    	Independent Contractors	  	 	117	  
	 13.14
	    	Non-solicitation of Key Employees	  	 	117	  
	 13.15
	    	Headings; Construction; Interpretation	  	 	117	  

  
 - v -

							
	 13.16
	    	Books and Records	  	 	118	  
	 13.17
	    	Further Actions	  	 	118	  
	 13.18
	    	Parties in Interest	  	 	118	  
	 13.19
	    	Performance by Affiliates	  	 	118	  
	 13.20
	    	Counterparts	  	 	118	  

 List of Exhibits 
  

					
	 Exhibit A
	 	-	  	Initial Research Plan
	 Exhibit B
	 	-	  	Form of CELGENE Provided Compound Transfer Agreement
	 Exhibit C
	 	-	  	[**]
	 Exhibit D
	 	-	  	Press Release
	 Exhibit E
	 	-	  	Redacted Version of the Agreement for Disclosure to Investors,
		 		  	Lenders, Acquirors and Merger Partners
	 Exhibit F
	 	-	  	Redacted Version of the Agreement for Disclosure to Potential
		 		  	Licensees, Sublicensees and Collaborators
	
	List of Schedules
			
	 Schedule 1.33
	 	-	  	Development Candidate Selection Criteria
	 Schedule 1.50
	 	-	  	EPIZYME Reserved Targets
	 Schedule 1.73
	 	-	  	Lead Candidate Criteria
	 Schedule 1.89
	 	-	  	[**]
	 Schedule 10.2(a)
	 	-	  	EPIZYME Patents
	 Schedule 10.2(b)
	 	-	  	EPIZYME Agreements
	 Schedule 13.14
	 	-	  	Key Employees

  
 - vi -

 COLLABORATION AND LICENSE AGREEMENT 

This COLLABORATION AND LICENSE AGREEMENT (the “Agreement”) is entered into and made effective as of the 2nd day of April, 2012 (the “Effective Date”) among
Epizyme, Inc., a Delaware corporation having its principal place of business at 325 Vassar Street Suite 2B, Cambridge, Massachusetts 02139, U.S.A. (“EPIZYME”), Celgene International Sàrl, having its principal place of
business at Route de Perreux 1, 2017 Boudry, Switzerland (“CELGENE”), and, solely for the purposes of 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 possesses proprietary technology and intellectual property to identify and develop novel, small molecule histone
methyltransferase (“HMT”) inhibitors; 
 WHEREAS, CELGENE possesses expertise in the Development and
Commercialization (each as defined below) of human pharmaceuticals; 
 WHEREAS, the Parties desire to engage in a collaborative
effort pursuant to which they will carry out research activities directed to Targets (as defined below), with the goal of identifying and Developing Compounds (as defined below) Directed to such Targets; and 

WHEREAS, CELGENE desires an option to obtain exclusive rights from EPIZYME to Develop and Commercialize such Compounds in the CELGENE
Territory (as defined below), on the terms and conditions set forth herein. 
 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 at any relevant
time during the Selection Term, Targets other than (a) the then-current Selected Targets, (b) the Lapsed Targets, (c) the EPIZYME Reserved Targets (provided that if [**] during the Option Term and prior to effectiveness
of an IND with respect to a Development Candidate (as defined in the [**]) Directed to such Selected Target, such Target shall become an “Available Target” under this Agreement), and (d) the Terminated 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, 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. 

  
 - 2 -

 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 2.2.5 prior to or upon expiration of the Option Term, or is thereafter deemed to be a CELGENE Development Candidate pursuant to Section 5.3. 

1.13 “CELGENE IP” means CELGENE Background IP, CELGENE Collaboration IP and CELGENE Provided Compound IP. 

1.14 “CELGENE Patent(s)” means CELGENE Background Patents, CELGENE Collaboration Patents and CELGENE Provided Compound
Patents. 

  
 - 3 -

 1.15 “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 2.2.2(a)(iii).

 1.16 “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 2.2.2(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). 

1.17 “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. 
 1.18 “CELGENE
Territory” means, on a Selected Target-by-Selected Target basis, the entire world except the United States and any Terminated Countries and, if EPIZYME exercises the EPIZYME Opt-Out pursuant to Section 3.8, as of the EPIZYME Opt-Out
Date, including the United States and any Terminated Countries. 
 1.19 “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 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. 
 1.20 “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. 
 1.21 “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. 
 1.22 “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. 
 1.23 “Collaboration IP” means, collectively: 

  
 - 4 -

 (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. 
 1.24 “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. 
 1.25
“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 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). 
 1.26 “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. 

  
 - 5 -

 1.27 “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). 
 1.28 “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 [**]. 
 1.29 “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 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 6.8.4, 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”. 

1.30 “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). 
 1.31 “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, but excluding EPIZYME Reserved Targets) and obtaining and maintaining Regulatory Approval thereof. 

  
 - 6 -

 1.32 “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 2.2.5 as meeting the applicable Development Candidate Selection Criteria, or is otherwise designated a Development
Candidate pursuant to Section 2.2.5, or is a CELGENE Development Candidate in accordance with Section 1.12 or pursuant to Section 5.3. 
 1.33 “Development Candidate Selection Criteria” means the criteria set forth on Schedule 1.33, as such criteria may be amended from time to time upon mutual agreement of the
Parties. 
 1.34 “Development Costs” means on a Development Program-by-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 2.7.4. 
 1.35 “Development Plan” means, with respect to each Development Program, a research and
Development plan governing the activities to be conducted by the Parties during the 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. 

1.36 “Development Program” means, for each Selected Target, 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 Selected Target, and
related Diagnostic Products, in the Field during the applicable Development Term. 
 1.37 “Development Term”
means, subject to early termination or exercise by EPIZYME of the EPIZYME Opt-Out pursuant to Section 3.8, on a Development Program-by-Development Program basis, the period commencing upon CELGENE’s exercise of the Celgene Option with
respect to the applicable Selected Target (unless such exercise is prior to the effectiveness of an IND with respect to a Compound Directed to the applicable Selected Target, in which case commencing upon the effectiveness of such IND), 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 has determined to pursue Regulatory
Approval. 
 1.38 “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. 

  
 - 7 -

 1.39 “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. 
 1.40 “Dollars” or “$” means the legal tender of the U.S. 
 1.41 “DOT1L” means DOT1L, exemplified in Okada et al. (2005) hDOT1L links histone methylation to leukemogenesis. Cell (121):167-178. 

1.42 “DOT1L Compound(s)” means any Licensed Compound Directed to DOT1L, including EPZ5676. 

1.43 “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. 
 1.44
“EMA” means the European Medicines Agency, and any successor entity thereto. 
 1.45 “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). 
 1.46 “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 1.45(a) constitutes EPIZYME Background IP. 

  
 - 8 -

 1.47 “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. 
 1.48 “EPIZYME IP” means EPIZYME Background IP and EPIZYME Collaboration IP. 
 1.49 “EPIZYME Patent(s)” means EPIZYME Background Patents and EPIZYME Collaboration Patents. 
 1.50 “EPIZYME Reserved Targets” means the Targets set forth in Schedule 1.50. 
 1.51 “EPIZYME Territory” means, on a Selected Target-by-Selected Target basis, the entire world except the CELGENE Territory. 

1.52 “EPZ5676” means the DOT1L Compound known as EPZ5676, which is the Development Candidate Directed to DOT1L as of the
Effective Date. 
 1.53 “EU” means all countries that are officially recognized as member states of the
European Union at any particular time during the Term. 
 1.54 “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). 
 1.55 “[**]” means [**]. 

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

1.57 “Field” means any use or purpose, including the treatment, palliation, diagnosis or prevention of any human or
animal disease, disorder or condition. 
 1.58 “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: 

  
 - 9 -

 (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. 
 1.59 “Global Development Costs” means all Development Costs incurred by the Parties in accordance with the applicable budget approved by the JDC, other than the Territory-Specific
Development Costs. 
 1.60 “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).

 1.61 “[**]” means [**]. 
 1.62 “[**] Agreement” means the Collaboration and License Agreement, dated [**], by and between [**] and EPIZYME. 
 1.63 “HSR Act” means the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended. 
 1.64 “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). 
 1.65 “Indication” means any human disease or
condition, or sign or symptom of a human disease or condition. 
 1.66 “Initiation” means, with respect to a
Clinical Trial, the first dosing of the first subject enrolled in such Clinical Trial with a Licensed Product. 
 1.67
“Joint Collaboration Chemistry IP” means Joint Collaboration IP that is also Chemistry IP. 

  
 - 10 -

 1.68 “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. 

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

 1.70 “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. 

1.71 “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. 
 1.72 “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 2.2.4 as
meeting the applicable Lead Candidate Criteria, or is otherwise designated a Lead Candidate pursuant to Section 2.2.4. 

1.73 “Lead Candidate Criteria” means the criteria set forth on Schedule 1.73, as such criteria may be amended
from time to time upon mutual agreement of the Parties. 
 1.74 “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,

  
 - 11 -

 
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 2.2.4 prior to the expiration of the applicable Selection Term, and (d) did not meet the Development Candidate Selection Criteria pursuant to Section 2.2.5 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 2.2.2(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 2.2.4 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 2.2.5 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, [**]. 
 1.75 “Legal
Exclusivity” means, with respect to a Licensed Product, (a) Patent-Based Exclusivity or (b) Regulatory-Based Exclusivity. 
 1.76 “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. 
 1.77 “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; and 
 (iii) determined to have an in vitro IC50 enzymatic potency of at least [**] and [**] selectivity relative to the
next most active Target; and 
 (b) a Related Compound with respect to the Compound described in the foregoing clause (a).

 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 1.77(a)(iii) pursuant to the terms of this Agreement to modify the selectivity threshold set forth in Section 1.77(a)(iii). 

  
 - 12 -

 1.78 “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. 
 1.79 “LLS” means The Leukemia and Lymphoma Society. 
 1.80
“LLS Agreement” means the Definitive Agreement, dated June 17, 2011, by and between LLS and EPIZYME. 

1.81 “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. 
 1.82 “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. 
 1.83 “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.

 1.84 “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. 
 1.85 “MMRF” means The Multiple
Myeloma Research Foundation, Inc. 
 1.86 “MMRF Agreement” means the Research Agreement, dated June 15,
2011, by and between MMRF and EPIZYME. 
 1.87 “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. 
 1.88 “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: 

  
 - 13 -

 (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. 
 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.

  
 - 14 -

 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 1.88, “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”. 

1.89 “[**]” means the Targets described on Schedule 1.89. 

1.90 “Out-of-Pocket Costs” means, with respect to activities performed under the applicable Research Plan or Development
Plan hereunder, 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. 
 1.91
“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. 

  
 - 15 -

 1.92 “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. 
 1.93 “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. 
 1.94 “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. 
 1.95 “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. 

1.96 “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. 

1.97 “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.

  
 - 16 -

 1.98 “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 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. 
 1.99 “Proof of Concept” means the demonstration, in a patient population with genotypic
or phenotypic evidence of target relevance, of both: 
 (a) an objective response (complete or partial response) in at least
[**] patients treated at a dose equal to or less than the maximum tolerated dose; and 
 (b) inhibition of a Target, to an
extent and duration previously established in preclinical studies, as evidenced by a change in histone methylation status in tumor, surrogate or relevant tissues, at a dose equal to or less than the maximum tolerated dose. 

For purposes of this Section 1.99, “objective response” will be based on RECIST criteria in solid tumors and working group criteria for
hematological cancers. 
 1.100 “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. 
 1.101 “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. 
 1.102 “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. 
 1.103 “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

  
 - 17 -

 
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. 

1.104 “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 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. 
 1.105 “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. 
 1.106 “Research Plan” means a research plan
governing the activities of the Collaboration to be conducted by the Parties (a) during the Option Term, with the goal of identifying Available Targets and Compounds Directed to the Available Targets that meet the applicable Development
Candidate Selection Criteria and advancing such Compounds to the filing of an IND and (b) upon expiration of the Option Term, with respect to each Selected Target, until the effectiveness of an IND with respect to a Development Candidate
Directed to the applicable Selected Target, if such IND is not filed or effectiveness is not achieved prior to expiration of the Option Term. 
 1.107 “Selection Term” means, on an Available Target-by-Available Target basis, the period commencing on July 9, 2012 and ending on the earliest of (a) [**] days after the [**]
filed in the United States or a Major EU Country with respect to a Development Candidate Directed to such Available Target (and if such IND does not become effective, the Selection Term shall continue until [**] or until terminated earlier pursuant
to clause (b) or (c)), (b) the end of the Option Term, or (c) the date that such Available Target becomes a Selected Target. 
 1.108 “Stock Purchase Agreement” means the Series C Convertible Preferred Stock Purchase Agreement, dated as of the Effective Date, by and between EPIZYME and Celgene European Investment
Company LLC, a Delaware limited liability company (“CELGENE EUROPE”), an Affiliate of CELGENE. 

  
 - 18 -

 1.109 “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 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. 
 1.110 “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.

 1.111 “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).

 1.112 “Third Party” means any Person other than EPIZYME or CELGENE that is not an Affiliate of EPIZYME or of
CELGENE. 
 1.113 “UNC” means The University of North Carolina at Chapel Hill. 

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

 1.115 “United States” or “U.S.” means the United States of America and all of its
territories and possessions. 
 1.116 “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. 

  
 - 19 -

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

			
	 Definition:
	  	 Section:

	 Achievement of Proof of Concept
	  	3.3.1
	 Additional Payments
	  	1.29
	 Agreement
	  	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
	  	6.5.2(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
	 CELGENE Background Patents
	  	1.10
	 CELGENE Collaboration Know-How
	  	1.11
	 CELGENE Collaboration Patents
	  	1.11
	 CELGENE EUROPE
	  	1.108
	 CELGENE Indemnitees
	  	11.2
	 CELGENE Lead Candidate
	  	5.3
	 Celgene Obligations
	  	13.21
	 Celgene Option
	  	2.4.1
	 CELGENE Patent Challenge
	  	12.4.1(b)
	 CELGENE Provided Compound Transfer Agreement
	  	2.2.2(a)(iii)(5)
	 Claims
	  	11.1
	 Collaboration
	  	2.1
	 Combination Product
	  	1.88
	 Competitive Infringement
	  	8.5.1
	 Confidential Information
	  	9.1
	 CRO
	  	2.2.2(a)(iii)(1)

  
 - 20 -

			
	 Definition:
	  	 Section:

	 CTA
	  	1.64
	 Development Cost Share
	  	6.5.1
	 Disclosing Party
	  	9.1
	 Discontinued Product
	  	6.7.6
	 Disputed Target
	  	2.3.3
	 Effective Date
	  	Preamble
	 EPIZYME
	  	Preamble
	 EPIZYME Agreements
	  	10.2(b)
	 EPIZYME Background Know-How
	  	1.46
	 EPIZYME Background Patents
	  	1.46
	 EPIZYME Collaboration Know-How
	  	1.47
	 EPIZYME Collaboration Patents
	  	1.47
	 EPIZYME In-Licenses
	  	10.2(b)
	 EPIZYME Indemnitees
	  	11.1
	 EPIZYME Opt-Out
	  	3.8
	 EPIZYME Opt-Out Date
	  	3.8
	 EPIZYME Patent Challenge
	  	12.4.2(b)
	 Existing Confidentiality Agreement
	  	9.4
	 Extension Fee
	  	6.3
	 GAAP
	  	1.1
	 Hit Criteria
	  	2.2.2(a)(iii)(1)
	 IFRS
	  	1.1
	 Indemnification Claim Notice
	  	11.3.1
	 Indemnified Party
	  	11.3.1
	 Indemnifying Party
	  	11.3.1
	 Initial Hit
	  	2.2.2(a)(iii)(1)
	 JCC
	  	4.3
	 JDC
	  	4.2
	 Joint Collaboration Know-How
	  	1.68
	 Joint Collaboration Patents
	  	1.68
	 JRC
	  	4.1
	 Key Employee
	  	13.14
	 Know-How Royalty
	  	6.8.2(b)
	 Lapsed Target
	  	2.4.5
	 Litigation Conditions
	  	11.3.2
	 Losses
	  	11.1
	 Lower Value Third Party Offer Condition
	  	7.2
	 M&A Event
	  	13.5
	 Major License Countries
	  	2.7.3(b)(i)
	 Manufacturing Subcommittee
	  	4.4.3(a)
	 Material Breach
	  	12.3.1
	 Material Receiving Party
	  	2.7.5(a)
	 Materials
	  	2.7.5(a)
	 Non-Breaching Party
	  	12.3.1(a)

  
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	 Definition:
	  	 Section:

	 Non-Paying Party
	  	6.6
	 Non-Proposing Party
	  	9.3.2
	 Notice of Exercise
	  	2.4.2
	 Once Confirmed Hit
	  	2.2.2(a)(iii)(2)
	 Opposing Party
	  	2.3.3
	 Option Exercise Milestone
	  	6.7.1
	 Option Term
	  	2.4.1
	 PARENT
	  	Preamble
	 Party or Parties
	  	Preamble
	 Patent Committee
	  	4.5
	 Patent Liaison
	  	4.5
	 Patent Strategy
	  	4.5.5(b)
	 Payee
	  	6.11
	 Payor
	  	6.11
	 Post-Regulatory Approval Opt-Out Period
	  	3.8
	 Pre-NDA Opt-Out Period
	  	3.8
	 Pre-Pivotal Opt-Out Period
	  	3.8
	 Pre-Regulatory Approval Opt-Out Period
	  	3.8
	 Proposed Targets
	  	2.3.3
	 Proposed Transaction
	  	7.2
	 Proposing Party
	  	9.3.2
	 Publishing Party
	  	9.6.2
	 Purpose
	  	2.7.5(a)
	 Receiving Party
	  	9.1
	 Recommending Party
	  	2.3.3
	 Registrational Use
	  	6.6
	 Residual Information
	  	9.1
	 Reviewing Party
	  	9.6.2
	 ROFN Expiration
	  	7.2
	 ROFN Right
	  	7.2
	 Royalty Term
	  	6.8.2(a)
	 Second Indication
	  	6.7.2
	 Selected Target(s)
	  	2.4.1
	 Selling Party
	  	1.88
	 Sensitive Information
	  	7.1.3(a)
	 Sole Paying Party
	  	6.6
	 Subcommittee
	  	4.4.3
	 Term
	  	12.1.1
	 Terminated Country
	  	12.6
	 Terminated Products
	  	12.6
	 Terminated Target
	  	12.6
	 Transfer Record
	  	2.7.5(a)
	 Transferring Party
	  	2.7.5(a)
	 Twice Confirmed Hit
	  	2.2.2(a)(iii)(4)

  
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 ARTICLE 2 
 COLLABORATION; RESEARCH PLAN; TARGET SELECTION 
 2.1 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 Available Targets for selection by CELGENE and identifying Compounds Directed to such Available Targets that meet the applicable Development Candidate Selection Criteria and, (b) if CELGENE selects
one or more Available Targets, following the effectiveness of an IND with respect to a Development Candidate Directed to the applicable Selected Target, the conduct of Development activities directed to Selected Targets under the applicable
Development Plan as set forth in Article 3 (the “Collaboration”). 
 2.2 Research Plan; Research
Activities. 
 2.2.1 Research Plan. The initial Research Plan is attached hereto as Exhibit A. 

2.2.2 Responsibilities. 
 (a) EPIZYME Responsibilities. During the Option Term and, with respect to each Selected Target, upon expiration of the Option Term until the effectiveness of an IND with respect to a Development
Candidate Directed to the applicable Selected Target, if such IND is not filed or effectiveness is not achieved prior to expiration of the Option Term: 
 (i) EPIZYME shall use Commercially Reasonable Efforts to conduct platform discovery activities necessary to characterize and identify Available Targets and Compounds Directed to Available Targets and
Selected Targets, as applicable. 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 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 2.2.2(a)(ii) and Section 2.2.2(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 

  
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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. 
 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 Targets unless and until such compound(s) become CELGENE Provided Compound(s) as set forth in this Section 2.2.2(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 2.2.2(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. 

  
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 (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. 
 2.2.3 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. 

2.2.4 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 determine whether or not a Compound satisfies the applicable Lead Candidate Criteria; [**]. 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. 
 2.2.5 Selection of Development Candidate. On an Available Target-by-Available Target or Selected Target-by-Selected Target basis, as applicable, the JRC shall determine whether or not a Compound
satisfies the applicable Development Candidate Selection Criteria; [**]. Upon the earlier of: (a) determination that any Compound satisfies the applicable Development Candidate Selection Criteria pursuant to the preceding sentence, or
(b) 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,
once an applicable Compound has met the Development Candidate Selection Criteria or has been deemed to be a Development Candidate, upon CELGENE’s request or at any time upon the mutual agreement of the Parties, the Parties shall work together
to develop a Development Plan for such Compound and such Available Target or Selected Target, as applicable; provided that, unless otherwise agreed by the Parties, activities under such Development Plan shall not commence prior to the
effectiveness of an IND with respect to such Compound and such Selected Target. 
 2.3 Targets. 

2.3.1 Overview. During the Option Term, EPIZYME shall use its Commercially Reasonable Efforts to conduct appropriate platform
discovery activities in order to characterize and identify Available Targets for selection by the Parties for Development in accordance with Section 2.3.3 and shall provide regular updates to CELGENE at JRC meetings in accordance with
Section 2.5, with respect to its activities pursuant to the Research Plan, together with all material data and information in EPIZYME’s possession relating to such Available Targets. 

  
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 2.3.2 Discussion of Available Targets. During the Option Term, EPIZYME shall notify
CELGENE, on a regular basis at JRC meetings, of Available Targets and Compounds identified by EPIZYME in the course of its ongoing platform discovery activities as well as notify CELGENE with respect to material developments in or new data or
information in EPIZYME’s possession and Control relating to previously identified Available Targets that remain Available Targets. Further, CELGENE may request that EPIZYME prioritize its platform discovery activities with respect to particular
Available Targets and EPIZYME shall consider such requests in good faith, taking into consideration the Parties’ discussion of the characteristics and scientific merits of such Available Targets. Without limiting the generality of the
foregoing, EPIZYME shall provide to CELGENE (a) at least [**] days prior to the expected filing of an IND for a particular Compound (including a Development Candidate) Directed to an Available Target, written notice of the expected achievement
of an IND filing, together with all material data and information within EPIZYME’s possession and control pertaining to such Available Target, (b) a final copy of the IND within [**] days of filing the IND, and (c) any communications
to and from the FDA with respect to such IND. 
 2.3.3 Inclusion of Available Targets in Research Plan. Beginning with
the first meeting of the JRC and at every other JRC meeting thereafter during the Option Term, i.e., [**], but in no event more than [**] months after the immediately preceding review, the Parties shall review a list of any Available Targets for
which activities are allocated in the Research Plan in the next [**] months or are identified by a Party (the “Proposed Targets”) and any available reports, data and other information related thereto. For each Proposed Target, the
Parties shall discuss whether to include such Proposed Target in the Research Plan. The Parties shall mutually agree on the inclusion of each Proposed Target, provided that [**]. 

2.4 Celgene Option; Target Selection. 
 2.4.1 Celgene Option. Commencing upon the Effective Date and continuing until and including July 9, 2015 or, if extended pursuant to Section 2.4.4, until and including July 9, 2016
(the “Option Term”), during the applicable Selection Term for an Available Target, CELGENE shall have the exclusive right, exercisable, at CELGENE’s sole discretion (the “Celgene Option”) in accordance with
this Section 2.4, to select Targets from the Available Targets (each, a “Selected Target”) against which the Parties 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 the Research Plan and, upon the effectiveness of an IND with respect to the applicable Licensed
Compound, 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 Celgene
Option with respect to each Available Target. 
 2.4.2 Exercise of Celgene Option. Except with respect to selection of
DOT1L (which is deemed to be a Selected Target as of the Effective Date), on an Available Target-by-Available Target basis, if CELGENE wishes to exercise the Celgene Option, CELGENE shall provide to EPIZYME written notice of exercise of such Celgene
Option with respect to the Available Target (“Notice of Exercise”) during the applicable Selection Term. Following any such Notice of Exercise by CELGENE, CELGENE shall pay EPIZYME the Option Exercise Milestone as set forth in
Section 6.7.1. 

  
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 2.4.3 Effect of Exercise of Celgene Option. Upon exercise of the applicable Celgene
Option with respect to an Available Target and CELGENE’s payment of the Option Exercise Milestone (except with respect to DOT1L, which is deemed to be a Selected Target as of the Effective Date) pursuant to Section 2.4.2, the following
shall occur: 
 (a) such Available Target shall become a Selected Target; 

(b) the Selection Term with respect to such Available Target shall terminate; and 

(c) with respect to such Available 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. 
 2.4.4
Extension of Option Term. CELGENE shall have the right, in its sole discretion, to extend the Option Term for one (1) additional year upon written notice to EPIZYME at least [**] days before expiration of the initial Option Term and
payment to EPIZYME of the Extension Fee as set forth in Section 6.3. 
 2.4.5 Expiration of Celgene Option. Subject
to Section 2.3.2, on an Available Target-by-Available Target basis, if CELGENE fails to provide its Notice of Exercise before the earlier of (a) expiration of the applicable Selection Term for such Available Target, and (b) expiration
of the Option Term, then (i) the Celgene 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. 
 2.5 Reports; Results. 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 or Selected Target-by-Selected Target basis, as applicable, 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 2.4.2, at least [**] Business Days in advance of each JRC meeting. 
 2.6
Subcontracting. 
 2.6.1 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 

  
 - 27 -

 
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). 
 2.6.2 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 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. 

2.7 Regulatory Matters; Compliance. 
 2.7.1 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. 

  
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 2.7.2 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. 

2.7.3 Regulatory Filings, Data and Approvals. For purposes of this Section 2.7.3, 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) Prior to Achievement of Proof of
Concept. Prior to Achievement of Proof of Concept of a Licensed Compound or Licensed Product, 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 such Licensed Compounds, Licensed Products and related Diagnostic Products in the Field worldwide. 
 (ii)
After Achievement of Proof of Concept. 
 (1) CELGENE Territory. Following Achievement of Proof of Concept of a
Licensed Compound or Licensed Product, 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 such Licensed Compounds, Licensed Products and related Diagnostic Products in the Field in the CELGENE Territory. CELGENE shall own all such regulatory filings and Regulatory Approvals relating to such Licensed Compounds,
Licensed Products and related Diagnostic Products in the CELGENE Territory. Subject to Sections 2.7.3(c) and 6.6, to the extent permitted by applicable Laws and following Achievement of Proof of Concept of a Licensed Compound or Licensed Product,
EPIZYME shall assign and transfer to CELGENE all regulatory filings and Regulatory Approvals in the CELGENE Territory that relate to such Licensed Compound, Licensed Product and related Diagnostic Product. 

(2) EPIZYME Territory. Following Achievement of Proof of Concept of a Licensed Compound or Licensed Product, EPIZYME shall
continue to have the sole right to prepare, file and maintain all regulatory filings (including pricing and reimbursement approvals) and Regulatory Approvals necessary for the Development, 

  
 - 29 -

 
Manufacture or Commercialization of such Licensed Compounds, Licensed Products and related Diagnostic Products in the Field in the EPIZYME Territory. EPIZYME shall own all such regulatory filings
and Regulatory Approvals in the EPIZYME Territory. 
 (iii) 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. 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, from and after Achievement of Proof of Concept of such Licensed Product. 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 EMA or the Major License Countries and shall promptly provide to EPIZYME all proposed
labeling, in each case received from the Regulatory Authorities in 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 2.7.3(b)(i) that are produced for its own use. 

  
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 (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 and related Diagnostic Products or
Regulatory Approvals worldwide (prior to Achievement of Proof of Concept) and in the EPIZYME Territory (after Achievement of Proof of Concept) 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 worldwide (prior to Achievement of Proof of Concept) or in the EPIZYME Territory
(after Achievement of Proof of Concept), 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 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 worldwide (prior to Achievement of Proof of Concept) or in the EPIZYME Territory (after Achievement of Proof of Concept). EPIZYME shall promptly provide to CELGENE
copies of any material documents or other material correspondence pertaining to the Licensed Product or related Diagnostic Product worldwide (prior to Achievement of Proof of Concept) or in the EPIZYME Territory (after Achievement of Proof of
Concept) and shall promptly provide to CELGENE all proposed labeling, in each case received from the Regulatory Authorities worldwide (prior to Achievement of Proof of Concept) or in the EPIZYME Territory (after Achievement of Proof of Concept).
Upon CELGENE’s reasonable written request, EPIZYME shall provide CELGENE with any English translations of the documents and correspondence described in this Section 2.7.3(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 Achievement of Proof of Concept for 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; provided that (i) EPIZYME shall transfer and assign to CELGENE all INDs in the CELGENE Territory that relate to Licensed Compounds and Licensed Products upon Achievement of Proof of Concept of such Licensed Compounds and
Licensed Products in accordance with Section 2.7.3(a)(ii)(1) or Section 3.3.1 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. 

  
 - 31 -

 
Subject to Section 6.6, 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 2.7.3(a)(iii) 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 6.6, 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. 

(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. 

2.7.4 Adverse Event Reporting; Global Safety Database. CELGENE shall be solely responsible for reporting all adverse drug
experiences associated with Licensed Compounds and Licensed Products in the Field in the CELGENE Territory. 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. 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. 

2.7.5 Material Transfer. 
 (a) Either Party (referred to in this Section 2.7.5 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 2.7.5 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. 

  
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 (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 2.6 or a Sublicensee pursuant to Section 5.1.5 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. 
 (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 2.7.5 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. 

  
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 (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 the effectiveness of an IND with respect to a Development Candidate Directed to the
applicable Selected Target, the Parties (acting through the JDC) shall establish a Development Plan if not previously established pursuant to Section 2.2.5, including a budget pursuant to Section 6.5.2(a), covering the discovery and global
Development of Licensed Compounds and Licensed Products Directed to the Selected Target, and related Diagnostic Products. Each Development Plan 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. Subject to Section 4.7, the Parties agree to conduct all of their
Development activities with respect to each Development Program in accordance with the applicable Development Plan and budget. 

3.2 Development Activities. 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 under the applicable Development Plan. Unless otherwise agreed by the Parties, 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 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 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 be Territory-Specific Development Costs of such Party. Further, in the event a Party desires to clinically Develop a Licensed
Compound or Licensed Product 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. 

  
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 3.3 Proof of Concept Determination. 

3.3.1 Achievement; Effect. On a Selected Target-by-Selected Target basis, following Initiation of a Clinical Trial designed to
achieve Proof of Concept, Proof of Concept shall be deemed to have been achieved upon the occurrence of any of the following (“Achievement of Proof of Concept”): (a) the Parties mutually agree that Proof of Concept has been
achieved; or (b) CELGENE unilaterally determines that Proof of Concept has been achieved based on data and results generated pursuant to such Clinical Trial. In the event that [**], the Parties shall [**]. In the event that [**], the Parties
shall be deemed to have [**]. Upon Achievement of Proof of Concept in accordance with this Section 3.3.1, [**]; (ii) [**]; (iii) CELGENE shall have final-decision making authority with respect to disputes arising in the JDC with
respect to the applicable Development Program as provided in Section 4.4.2(a)(ii); and (iv) subject to Section 6.6, EPIZYME shall assign and transfer to CELGENE all INDs in the CELGENE Territory that relate to Licensed Compounds and
Licensed Products Directed to the applicable Selected Target. 
 3.3.2 Futility Criteria. On a Licensed
Compound-by-Licensed Compound basis, prior to Initiation of any Clinical Trial that is prior to or designed to achieve Proof of Concept with respect to such Licensed Compound, the Parties shall promptly (through the JDC) mutually define futility
criteria for the termination of such Clinical Trial; provided that such Clinical Trial may not commence until the Parties have mutually agreed upon such criteria, which agreement shall not be unreasonably withheld or delayed. Neither
Party may unilaterally modify such futility criteria. Notwithstanding the foregoing, if CELGENE believes that a Clinical Trial that is prior to or designed to achieve Proof of Concept should be discontinued and EPIZYME wants to continue such
Clinical Trial for the applicable Development Candidate, EPIZYME may continue such Clinical Trial; provided that, in such event, the subject enrollment for such Clinical Trial shall not exceed [**] subjects unless otherwise agreed by
the Parties. For the avoidance of doubt, neither Party may proceed with a Clinical Trial in the event the futility criteria are met. 
 3.4 Reports. On a Development Program-by-Development Program basis, during the applicable Development Term, each Party shall provide the other Party with written reports summarizing in reasonable
detail (to the extent applicable) 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 3.4, 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. 

  
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 3.5 Commercialization. 

3.5.1 Responsibility. On a Development Program-by-Development Program basis, following completion of the applicable Development
Term, CELGENE 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 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. 
 3.5.2 Meetings. Without
limiting the generality of any of the foregoing in this Section 3.5, on a Development Program-by-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 to Commercialize Licensed Compounds, Licensed Products and Diagnostic Products of such Development Program. 

3.5.3 Reports; Results; Adverse Events. 
 (a) On a Development Program-by-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 in reasonable detail (to the extent applicable) the material activities and anticipated plans of such Party, its Affiliates and Sublicensees with respect to the Commercialization of Licensed Compound, 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 3.5.2). 
 (b) 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 2.7.4, provided that 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. 
 3.6 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 [**]. 
 3.7 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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 3.8 EPIZYME Opt-Out. 

3.8.1 Notice of Opt-Out. On a Selected Target-by-Selected Target basis, EPIZYME shall have the right, in its sole discretion, to
elect to exercise an “EPIZYME Opt-Out”, pursuant to which EPIZYME opts-out of further participation in: 
 (a)
Development with respect to the applicable Development Program, such EPIZYME 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 Development Program (the “Post-Regulatory Approval Opt-Out Period”); 
 in each case by providing written notice to CELGENE of such election. Any such EPIZYME Opt-Out shall, subject to Section 3.8.4, take effect [**] days after the date of such written notice (the
“EPIZYME 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 3.8.5. Subject to Sections 3.8.2(c), 3.8.2(d), 3.8.3(a) and 3.8.3(b), EPIZYME shall not be responsible for Global Development Costs regarding the
applicable Development Program incurred after the EPIZYME Opt-Out Date. 
 3.8.2 Effect of Pre-Regulatory Approval
Opt-Out. In the event EPIZYME exercises the EPIZYME 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 Development Program within [**] days after
the EPIZYME Opt-Out Date; 
 (b) EPIZYME and CELGENE shall continue to share Global Development Costs in accordance with the
applicable budget under Section 6.5 through the EPIZYME Opt-Out Date, including any Global Development Costs that are incurred through and including the EPIZYME Opt-Out Date, even if payment of such Development Cost is not invoiced or paid
until after the EPIZYME Opt-Out Date; 
 (c) with respect to any ongoing Clinical Trials with respect to such 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 Opt-Out Date that it wishes to assume responsibility, EPIZYME shall continue to conduct any ongoing Clinical Trials, subject to Section 2.7.1, with respect to such Development Program only with regard to those patients enrolled
at the date of the EPIZYME 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

  
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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 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 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; 
 (d) with respect to any
ongoing Clinical Trials with respect to such 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 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 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 2.7.1, or to wind down such
Clinical Trial, (3) between the EPIZYME 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 Opt-Out Date; it being understood and agreed that following an EPIZYME 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 Development Program prior to the EPIZYME Opt-Out Date within [**] days after the EPIZYME Opt-Out Date; 
 (f) without limiting the generality of the remainder of this Section 3.8.2, 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 Development Program in accordance with a transition plan to be mutually agreed by the Parties; 

(g) subject to Section 3.8.5(c), the sales milestone payment of Section 6.7.3 and the royalty provisions of Sections
6.8.1(a)(ii) and 6.8.1(b)(ii) shall apply to the Licensed Products within such Development Program, without any retroactive application of such provisions; and [**] shall immediately and automatically [**]; 

  
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 (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 Development Program shall terminate as of the EPIZYME Opt-Out Date; 

(i) subject to Section 3.8.5(c), EPIZYME shall and hereby does grant to CELGENE commencing upon the EPIZYME 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 5.1.5), 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 Development Program; 
 (j) subject to Section 3.8.5(c), the CELGENE Territory with respect to such 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 Development Program, which shall no longer be within the purview of the JDC (and in the
event EPIZYME has opted-out of all Development Programs, the JDC shall be disbanded); 
 (l) notwithstanding anything to the
contrary in this Agreement, CELGENE shall not 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 in the EPIZYME Territory; 
 (m) the Parties’ exclusivity obligations with respect to such Selected Target under
Section 7.1 shall survive; and 
 (n) subject to Section 3.8.5(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 Development Program. Subject to Section 3.8.5(c), EPIZYME
shall reasonably cooperate with CELGENE with respect to the foregoing activities set forth in this Section 3.8.2; 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.

  
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 For purposes of clarity, except as provided in Sections 3.8.2(c) and (d) above, after the EPIZYME
Opt-Out Date, CELGENE shall be responsible for all Development Costs for such 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 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 3.8.2, which shall continue for the remainder of the Term. 

3.8.3 Effect of Post-Regulatory Approval Opt-Out. In the event EPIZYME exercises the EPIZYME 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 Opt-Out Date that it wishes to assume responsibility, EPIZYME shall continue to conduct any ongoing Clinical Trials, subject to Section 2.7.1, with respect to such Licensed Products only with regard to
those patients enrolled at the date of the EPIZYME 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 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 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; 
 (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 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 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 2.7.1, or to wind down such Clinical Trial, (3) between the EPIZYME 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 

  
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payment of such cost is not invoiced or paid until after the EPIZYME Opt-Out Date; it being understood and agreed that following an EPIZYME 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 3.8.3, 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 3.8.5(c), the sales milestone payment of Section 6.7.3 shall not apply to the applicable Licensed Products, but the royalty provisions of Sections 6.8.1(a)(ii) and 6.8.1(b)(ii) shall apply to such Licensed Products; and
[**] shall immediately and automatically terminate as of the EPIZYME Opt-Out Date with respect to such Licensed Products and related Diagnostic 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 Opt-Out Date; 
 (g) subject to Section 3.8.5(c), EPIZYME shall and hereby does grant to CELGENE commencing
upon the EPIZYME 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 5.1.5), 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 3.8.5(c), the CELGENE Territory with respect to such
Development Program shall expand to include the EPIZYME Territory (including the United States); 
 (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) notwithstanding anything to the contrary in this Agreement, CELGENE shall not be required to use Commercially Reasonable Efforts
with respect to the Development, Manufacturing and Commercialization of the applicable Licensed Compounds and Licensed Products in the EPIZYME Territory; 

  
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 (k) the Parties’ exclusivity obligations with respect to such Selected Target under
Section 7.1 shall survive; and 
 (l) subject to Section 3.8.5(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 Development Program. Subject to Section 3.8.5(c), EPIZYME
shall reasonably cooperate with CELGENE with respect to the foregoing activities set forth in this Section 3.8.3; 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 3.8.3(a) and (b), after the EPIZYME 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 3.8.3, which shall continue for the remainder of the Term. 
 3.8.4 Termination.
Notwithstanding anything in this Section 3.8 to the contrary, EPIZYME’s exercise of its EPIZYME Opt-Out shall not take effect if, prior to the EPIZYME 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. 

3.8.5 HSR Approval. 
 (a) Subject to the terms and conditions of this Agreement (including Section 3.8.4), 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 an EPIZYME Opt-Out as soon as practicable after any applicable written notice by EPIZYME of an EPIZYME Opt-Out under Section 3.8, including
(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 such written notice, 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 EPIZYME Opt-Out, 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. 

  
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 (b) In furtherance and not in limitation of the foregoing but subject to this
Section 3.8, 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 [**] days, after the date of written notice by
EPIZYME of an EPIZYME Opt-Out under Section 3.8, 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 EPIZYME Opt-Out 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 Opt-Out, 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 6.7.3, 6.8.1(a)(ii) and 6.8.1(b)(ii) shall not apply in any event,
(iv) subject to Sections 3.8.2(c) and 3.8.3(a), but notwithstanding Sections 3.8.2(d) and 3.8.3(b), EPIZYME shall not be responsible for Global Development Costs regarding the applicable Development Program incurred [**] days after the date of
the applicable written notice described in Section 3.8.1, and (v) notwithstanding anything to the contrary, the following provisions shall apply, as applicable: 3.8.2(h), 3.8.2(k), 3.8.2(m), 3.8.3(f), 3.8.3(i), and 3.8.3(k), effective [**]
days after the date of the applicable written notice described in Section 3.8.1. 
 ARTICLE 4 

GOVERNANCE 

4.1 Joint Research Committee. As soon as possible after the Effective Date, the Parties shall establish a joint research committee
(the “JRC”) 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. 

  
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 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. The first scheduled meeting of the JRC shall be held no later than [**] unless otherwise agreed by the Parties.
Thereafter, until the later of (a) expiration of the Option Term and (b) the effectiveness of an IND with respect to a Development Candidate Directed to the last Selected Target, 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 the later of (a) expiration of the Option Term and (b) the effectiveness of an IND with
respect to a Development Candidate Directed to the last Selected Target, 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: 
 (a) review and monitor progress of the Collaboration under the Research Plan; 

(b) discuss Target prioritization and inclusion in accordance with Sections 2.3.2 and 2.3.3; 

(c) discuss Target validation activities; 
 (d) determine chemistry strategy; 
 (e) determine lead optimization strategy,
including in vivo pharmacology; 
 (f) 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; 
 (g) determine whether the
applicable Lead Candidate Criteria have been achieved by any Compound, subject to Section 2.2.4; 

  
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 (h) 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; 
 (i) determine
whether the applicable Development Candidate Selection Criteria has been achieved by any Compound, subject to Section 2.2.5, and discuss and develop the Development Plan for a Compound, as set forth in Section 2.2.5; 

(j) 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; 
 (k) discuss and attempt to resolve any deadlocked issues submitted to it in accordance
with the procedures established in Section 4.4.2; 
 (l) develop, review and approve amendments to the Research Plan;

 (m) attempt to resolve any dispute in any Subcommittee of the JRC; and 

(n) 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. 
 4.2 Joint Development Committee. As soon as possible after the Effective Date, the Parties shall establish a
joint development committee (the “JDC”) for DOT1L and, as Development Plans are developed pursuant to Sections 2.2.5 and 3.1, the applicable Targets, as more fully described in this Section 4.2 and subject to Sections 2.2.5 and
3.1. The JDC shall have review, oversight and decision-making responsibilities for all activities performed under the Development Plan for each Development Program during the applicable Development Term, including the overall global Development
strategy of Licensed Products and related Diagnostic Products, as more specifically provided herein. Each Party agrees to keep the JDC informed of its progress and activities under the Development Program. The JDC may establish Subcommittees as set
forth in Section 4.4.3. 
 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 

  
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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. Prior to the Achievement of Proof of Concept by a Compound (including Licensed Compound) or Licensed Product in a Development Program, [**] shall have the right to designate the chairperson of the JDC for
such Development Program. After Achievement of Proof of Concept by a Compound (including Licensed Compound) or Licensed Product in a Development Program, [**] shall have the right to designate the chairperson of the JDC for such Development Program,
[**]. 
 4.2.2 Meetings. The first scheduled meeting of the JDC shall be held no later than [**] unless otherwise agreed
by the Parties. Thereafter, prior to the expiration of all Development Terms, 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, 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, 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; 

(b) review and monitor progress of the Collaboration under the Development Plans, including any Development Plans for Compounds
developed pursuant to Section 2.2.5; 
 (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 

  
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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 2.7.1; 

(e) develop, review and approve amendments to the Development Plans, including the annual budget therefor as described in
Section 6.5.2(a) and the futility criteria pursuant to Section 3.3.2, which futility criteria can only be amended by mutual agreement of the Parties; 
 (f) determine whether Proof of Concept has been achieved by a particular Compound (Licensed Compound) or Licensed Product, subject to Section 3.3; 

(g) subject to Section 3.3.2, 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; 

(h) determine if and when the Parties shall commence good faith discussion with respect to entering into a pharmacovigilance agreement
pursuant to Section 2.7.4; 
 (i) discuss and attempt to resolve any deadlocked issues submitted to it in accordance with
the procedures established in Section 4.4.2; 
 (j) attempt to resolve any dispute in any Subcommittee of the JDC; and

 (k) 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. 
 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. Within [**] days after Achievement of Proof of Concept with respect to
any Licensed Compound or Licensed Product, the Parties shall establish a joint commercialization committee (the “JCC”) 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, 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. The JCC may establish Subcommittees as set forth in Section 4.4.3. 

  
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 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. The first scheduled meeting of the JCC shall be held within [**] months after the JCC has been established.
Thereafter, for the remainder of 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 Development Program; provided that the JDC shall retain decision-making authority in accordance with Section 4.2 and 4.4 over all such matters; 

(b) facilitate discussion and consultation regarding pricing and reimbursement approvals in each Party’s Territory pursuant to
Section 2.7.3(d); 
 (c) discuss each Party’s efforts to Commercialize Licensed Compounds, Licensed Products and
related Diagnostic Products pursuant to Section 3.5.2 and facilitate the provision of reports pursuant to Section 3.5.3(a); 
 (d) discuss and determine strategy for the Manufacture and Commercialization of Licensed Products and related Diagnostic Products 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 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 

  
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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 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) Prior to Achievement of Proof of Concept. Subject to Sections 2.2.4, 2.2.5, 2.3.3, 2.7.1, 3.2, 3.3, and
4.4.2(b) and (c), [**] shall have final decision-making authority with respect to any matter relating to activities under the Research Plan and 

  
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any Development Program prior to Achievement of Proof of Concept for a Compound (including Licensed Compound) or Licensed Product in such Development Program. For purposes of clarity, this
Section 4.4.2(a)(i)does not apply to the JCC or the Patent Committee. 
 (ii) After Achievement of Proof of
Concept. Subject to Sections 2.2.4, 2.2.5, 2.3.3, 2.7.1, 3.2, 3.3, and 4.4.2(b) and (c), [**] shall have final decision-making authority with respect to any matter relating to any Development Program after Achievement of Proof of Concept for a
Licensed Compound or Licensed Product in such Development Program, 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)(ii) does not apply to the JCC or the Patent Committee. 
 (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 6.6, decide to pursue a Pivotal Clinical Trial 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; or (viii) 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 Development Program in the EPIZYME Territory, in each case, with a Third Party, (1) following exercise by CELGENE of the Celgene Option with
respect to a Selected Target, the Parties shall [**] on issues solely related to the applicable Development Program that arise for the applicable Compounds (including Licensed Compounds), Licensed Products and Diagnostic Products in such Development
Program, with respect to such Business Combination or License Event, and (2) each Party shall have [**] 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 

  
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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. 
 (a) Manufacturing Subcommittee. Within [**] days after the Effective Date, the Parties will
establish a Subcommittee under the JDC for Manufacturing (including CMC) related matters, which shall initially be 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 2.2.5) (the “Manufacturing Subcommittee”). Notwithstanding anything to the contrary in this Agreement, on a Licensed Compound-by-Licensed Compound basis,
(i) prior to Achievement of Proof of Concept, EPIZYME shall have final decision-making authority with respect to all Manufacturing matters in such CMC Subcommittee and (ii) after Achievement of Proof of Concept, [**] 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 Achievement of Proof of Concept with respect to the applicable Licensed Compound, 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. Promptly (but no later than [**]
days) after the Effective Date, the Parties shall (a) each designate representative(s) to consult with the other Party’s representative(s) with respect to Patent ownership, Prosecution and Maintenance, enforcement and defence matters (the
“Patent Liaisons”), and (b) establish a patent committee (the “Patent Committee”), 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 defence 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 Maintenance, enforcement and defence to participate on the Patent Committee. Each Party may,

  
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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 defence 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 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 

  
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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 defence 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 defence 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 defence, as
applicable, as set forth in Article 8. 

  
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 4.6 Alliance Managers. Promptly after the Effective Date, each Party shall appoint
an individual to act as alliance manager for such Party (each, an “Alliance Manager”). 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 Achievement of Proof of Concept for a 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 Achievement of Proof of Concept for a 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 and, with respect to each Selected Target, upon expiration of the Option Term until the effectiveness of an IND with respect to a Development
Candidate Directed to the applicable Selected Target, if such effectiveness is not achieved prior to expiration of 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 5.1.5), 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 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 

  
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Section 5.2.4 and Section 5.4) in the Field in the CELGENE Territory, with the right to grant sublicenses (subject to Section 5.1.5), 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. 
 5.1.3 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), 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 5.1.5), 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 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. 

5.1.4 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 5.1.5), 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. 

5.1.5 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 5.1.4 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 5.1.4 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 5.1.5 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 5.1.5. 

  
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 5.1.6 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 5.1.6(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. 

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 and, with respect to each Selected Target, upon expiration of the Option
Term until the effectiveness of an IND with respect to a Development Candidate Directed to the applicable Selected Target, if such effectiveness is not achieved prior to expiration of 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 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), CELGENE hereby grants to EPIZYME a royalty-free,
exclusive right and license (even as to CELGENE and its Affiliates, except as provided in Section 5.1.3 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 

  
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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), 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 5.1.3 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 the 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, 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 Provided Compound IP, to (i) conduct activities with respect to 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 the 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 

  
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Affiliates, except as provided in Section 5.1.3 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 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), 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 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 the
applicable Selected Target, and related Diagnostic Products. 
 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. 

  
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 5.3 Licenses to CELGENE Lead Candidates. On a CELGENE Development
Candidate-by-CELGENE Development Candidate basis, in the event CELGENE exercises the applicable Celgene 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 2.2.4, but
did not meet the Development Candidate Selection Criteria pursuant to Section 2.2.5. 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 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 5.1.5 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 2.2.5 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 2.2.5, 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 6.7.4. 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 2.2.4 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 1.74. 

  
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 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 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 6.5 or Section 6.6, as applicable. 
 ARTICLE 6 

FINANCIAL TERMS 
 6.1 Upfront Fee. In partial consideration for the licenses granted to CELGENE hereunder, CELGENE shall pay EPIZYME a payment of Sixty-Five Million Dollars ($65,000,000) on the Effective Date. Such
payment shall be payable by wire transfer of immediately available funds in accordance with Section 6.11. 

  
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 6.2 Purchase of Shares. On the Effective Date, EPIZYME shall sell to CELGENE EUROPE
and CELGENE EUROPE shall purchase from EPIZYME 9,803,922 shares of Series C Preferred Stock, par value $0.0001 per share, of EPIZYME at a purchase price of $2.55 per share, having an aggregate purchase price of Twenty Five Million Dollars
($25,000,000) pursuant to the Stock Purchase Agreement. 
 6.3 Celgene Option Extension Fee. If CELGENE elects to extend
the Option Term for one (1) additional year pursuant to Section 2.4.4, CELGENE shall upon such election, pay EPIZYME a payment of [**] Dollars ($[**]) (the “Extension Fee”). The Extension Fee shall be payable by wire
transfer of immediately available funds in accordance with Section 6.11. 
 6.4 Research Funding During the Selection
Term. Subject to Section 6.5.1, 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. 

6.5 Development Funding. 
 6.5.1 Overview. On a Development Program-by-Development Program basis, except for any Territory-Specific Development Costs to be paid by the applicable Party pursuant to Section 6.6 and
subject to Section 3.8, 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 incurred by EPIZYME through the effectiveness of the first IND 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 6.5.1(z), and (z) after the later of the expiration of the Option Term or the effectiveness of the first IND with respect to the applicable Compound in the U.S. or Europe, 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 the 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 6.5.2(d). 
 6.5.2 Annual Budgets;
Payment and Reconciliation of Global Development Costs. 
 (a) On a Development Program-by-Development
Program basis, subject to Section 3.8, 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 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 

  
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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 Development Program-by-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. 

6.6 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 shall be borne [**] percent ([**]%) 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 6.6, 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 6.6.

  
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 6.7 Milestones. 

6.7.1 Non-DOT1L Selected Targets. 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 Selected Target except DOT1L, on a Selected Target-by-Selected Target basis.

  

					
	 Milestone Event
(For each Selected Target)
	  	Milestone
Payments
(in $ [**])	 
	 [**]
	  	 	[**]	  
	 [**]
	  	 	[**]	  
	 [**]
	  	 	[**]	  
	 [**]
	  	 	[**]	  
	 [**]
	  	 	[**]	  
	 [**]
	  	 	[**]	  
	 [**]
	  	 	[**]	  

 6.7.2 DOT1L. 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 each Selected Target)
	  	Milestone
Payments
(in $ millions)	 
	 Achievement of Proof of Concept of a Licensed Compound Directed to the applicable Selected
Target 
	  	 	25	  
	 [**]
	  	 	[**]	  
	 [**]
	  	 	[**]	  

  
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	 Milestone Event
(For each Selected Target)
	  	Milestone
Payments
(in $ [**])	 
	 [**]
	  	 	[**]	  
	 [**]
	  	 	[**]	  
	 [**]
	  	 	[**]	  

 [**]. 
 6.7.3 Sales Milestone for EPIZYME Opt-Out During the Pre-Regulatory Approval Opt-Out Period. 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 each Selected Target for which EPIZYME has exercised its EPIZYME Opt-Out during the Pre-Regulatory Approval Opt-Out Period pursuant to
Section 3.8, subsequent to the EPIZYME Opt-Out Date: 
  

									
	 Milestone Event
(For each Selected Target)
	 	Milestone Payments
(in $ [**]) if
EPIZYME opted-out
during the Pre-
Pivotal
Opt-Out
Period with respect
to such Development
Program	 	 	Milestone Payments
(in $ [**]) if
EPIZYME opted-out
during the Pre-NDA
Opt-Out
Period with
respect to such
Development
Program	 
	 Annual Net Sales in the United States exceed [**] ($[**])
	 	 	[**]	  	 	 	[**]	  

 6.7.4 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 $
[**])	 
	 [**]
	  	 	[**]	  
	 Annual Net Sales (for such purposes, substituting Lead Candidate Product for Licensed Product in the definition of Net Sales)
worldwide exceed [**] ($[**])
	  	 	[**]	  

 [**]. 

  
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 6.7.5 If, upon achievement of a particular milestone event set forth in the table in
Section 6.7.1 or Section 6.7.2 as applicable, any of the applicable previous milestone payments for milestone events (1) through (6) set forth in the tables in Section 6.7.1 and Section 6.7.2, has not been paid for such
Selected Target (including DOT1L), then such milestone payment(s) shall be payable concurrently with the payment for such subsequent achievement. 
 6.7.6 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. 
 6.7.7 Upon achievement by or on behalf of EPIZYME, its
Affiliates or Sublicensees of a milestone event set forth in this Section 6.7, 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 6.7, 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 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). 
 6.8 Royalties. 
 6.8.1 Royalties in the CELGENE Territory.

 (a) Licensed Products not Directed to DOT1L. 

(i) CELGENE shall pay EPIZYME royalties on Annual Net Sales by CELGENE, its Affiliates and Sublicensees in the CELGENE Territory
(provided that on a Selected Target-by-Selected Target basis, if EPIZYME has exercised its EPIZYME Opt-Out as to such Selected Target, for purposes of this Section 6.8.1(a)(i), the CELGENE Territory shall not include the United
States notwithstanding any expansion of the CELGENE Territory resulting from the EPIZYME Opt-Out), on a Licensed Product-by-Licensed Product basis, for all Licensed Products Directed to a Selected Target other than DOT1L, at the royalty rates set
forth in the table below: 

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

 (ii) In the event EPIZYME has exercised its EPIZYME Opt-Out pursuant to Section 3.8, 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 Opt-Out the CELGENE Territory expands to include the United States, CELGENE shall pay EPIZYME royalties on Annual
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 a Selected Target other than DOT1L, at the royalty rates set forth in the table below:

  

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

 (b) Licensed Products Directed to DOT1L. 

(i) CELGENE shall pay EPIZYME royalties on Annual Net Sales by CELGENE, its Affiliates and Sublicensees in the CELGENE Territory
(provided that if EPIZYME has exercised its EPIZYME Opt-Out as to DOT1L, for purposes of this Section 6.8.1(b)(i), the CELGENE Territory shall not include the United States notwithstanding any expansion of the CELGENE Territory
resulting from such EPIZYME 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: 

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

 For example, if Annual Net Sales by CELGENE, its Affiliates and Sublicensees in the CELGENE Territory of a Licensed
Product that is Directed to a Selected Target other than DOT1L were $[**], the royalties payable with respect to such Annual Net Sales, subject to adjustment as set forth in this Section 6.8 below, would be [**]. 

(ii) In the event EPIZYME has exercised its EPIZYME Opt-Out pursuant to Section 3.8, 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 Opt-Out the CELGENE Territory expands to include the United States, CELGENE shall pay EPIZYME royalties on Annual 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: 

 

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

 6.8.2 Royalty Term and Adjustments. 

(a) CELGENE’s royalty obligations to EPIZYME under this Section 6.8 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: 

  
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 (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 6.8 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 6.8.1 or 6.8.2
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”). 
 6.8.3 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 6.8.1 or
Section 6.8.2 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 1.27(b)(i) or (b) [**] percent ([**]%) in the event
market share is reduced as set forth in Section 1.27(b)(ii), in each case, of the royalties otherwise payable pursuant to Sections 6.8.1 and 6.8.2. 
 6.8.4 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 6.8.4
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 6.8.1 or Section 6.8.2; 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 6.8.4(d) and 10.4(f), (i) if CELGENE elects to
obtain such sublicense, CELGENE would pay [**] percent 

  
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([**]%) 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 6.8.4(a) - (c), inclusive, including the payment provisions therein, shall not apply with respect to such Third Party license. 

  
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 6.8.5 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 6.8.2(b), 6.8.3 and 6.8.4, 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 6.8.1. 

6.9 [**] EPIZYME’s [**], the Parties shall [**] and [**]. 
 6.10 Reports; Royalty Payments. 
 6.10.1 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 6.10 shall be considered Confidential Information of
CELGENE. 
 6.10.2 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 6.8.2(b), 6.8.3, 6.8.4 and 6.8.5 and a calculation of royalties due. 

6.10.3 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. 
 6.11 Methods of Payments; Payments Non-Refundable and Non-Creditable.

 6.11.1 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. 

6.11.2 The payments due from CELGENE to EPIZYME under Sections 6.1, 6.3 and 6.7 shall be non-refundable and non-creditable (except as
permitted under Section 12.7.3 or as agreed by the Parties in an agreement entered into pursuant to Section 6.9); provided that nothing in this Section 6.11.2 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. 
 6.12 Accounting. 

6.12.1 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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 6.12.2 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. 
 6.12.3 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. 
 6.12.4 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. 
 6.13 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 6.13, 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 been imposed but for (i) the failure by EPIZYME to qualify for an exemption from or
reduction 

  
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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. 
 6.14 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. 
 6.15 Diagnostic Products. If CELGENE or any of its
Affiliates or sublicensees Commercializes a Diagnostic Product under the license granted to CELGENE pursuant to Section 5.1.2, 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; RIGHT OF FIRST NEGOTIATION 
 7.1 Selected 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 any 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 any Target; 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 6.6 or engaging Third-Party subcontractors in accordance with Section 2.6. 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 apply to CELGENE and its Affiliates, but shall not apply 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, after the Option Term and 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 6.6 or engaging Third-Party subcontractors in accordance with Section 2.6. For purposes of
clarity, the foregoing sentence 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, EPIZYME Reserved 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. 

  
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 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 Targets or (ii) a Party acquires a Third Party that has a material pharmaceutical program other than programs directed to Targets
(including by a merger or consolidation) so 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 Targets (each of (i), 

  
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(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 2.5; reports or timelines provided pursuant to Section 3.4;
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) [**]. In the event [**], (i) nothing in this Agreement [**] under this Agreement with respect to the [**]. 

(c) Lapsed Targets; EPIZYME Reserved Targets and GSK Agreement Research. Nothing in this Section 7.1 shall limit
EPIZYME’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 or Commercialization), or
Commercialize in the Field any Compounds (other than Licensed Compounds Directed to Selected Targets) Directed to Lapsed Targets or EPIZYME Reserved Targets; (ii) at any time anywhere in the world grant a license or sublicense to any Third
Party, to research (including 

  
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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 EPIZYME Reserved Targets; (iii) at any time anywhere in the world, perform ongoing platform discovery activities; or (iv) prior to [**], alone or with [**], research (including screen), Develop, Manufacture (for
research or Development), in the Field any Compounds (other than Licensed Compounds Directed to Selected Targets) Directed to Targets in accordance with the GSK Agreement. 
 7.2 Right of First Negotiation. EPIZYME hereby grants to CELGENE, on the terms set forth in this Section 7.2, a right of first negotiation with respect to a Business Combination of EPIZYME
(the “ROFN Right”) during the Option Term. If, during the Option Term, EPIZYME desires, directly or indirectly (including through any parent or holding corporation or entity or group of controlling stockholders acting together) to
pursue a Business Combination (a “Proposed Transaction”), then prior to negotiating the terms of an agreement for the Proposed Transaction with one or more Third Parties, EPIZYME shall notify CELGENE in writing of EPIZYME’s
desire to pursue a Proposed Transaction and, during the period beginning on the date on which EPIZYME so notifies CELGENE and ending upon the ROFN Expiration (as defined below), none of EPIZYME, its Affiliates, and its and their respective officers,
directors, employees, agents, attorneys, accountants, financial advisers, and representatives shall, directly or indirectly, solicit, initiate or encourage proposals from, discuss or negotiate with, or provide any information to, any Third Party
related to the Proposed Transaction. CELGENE shall, within [**] days after receipt of such notice, indicate to EPIZYME in writing whether it wishes to enter into the Proposed Transaction and, if CELGENE indicates that it wishes to enter into the
Proposed Transaction, the Parties shall negotiate in good faith to enter into mutually agreeable terms pursuant to which CELGENE would enter into such Proposed Transaction with EPIZYME, it being understood and agreed that the foregoing negotiation
obligation shall not require EPIZYME to accept any offer made by CELGENE or to enter into the Proposed Transaction. If either (a) CELGENE indicates it does not wish to pursue a Proposed Transaction, (b) CELGENE fails to indicate its
interest within such [**] day period or (c) CELGENE indicates it wishes to enter into such Proposed Transaction but the Parties fail to reach agreement on the terms of a Proposed Transaction or to execute a definitive agreement with respect to
such Proposed Transaction prior to the earlier of [**] days after the date of CELGENE’s indication of interest or the expiration of the Option Term, then the ROFN Right shall expire (the “ROFN Expiration”) and EPIZYME shall be
free, without any further obligation to CELGENE under this Agreement with respect thereto, to enter into the Proposed Transaction with a Third Party; provided that, in the event clause (c) of this sentence is applicable, if
EPIZYME proposes to enter into a Proposed Transaction with a Third Party during the Option Term on terms that (i) include an upfront purchase price payment (inclusive of amounts placed into an escrow account concurrently with such upfront
purchase price payment) that is less than or equal to the upfront purchase price payment (inclusive of amounts placed into an escrow account concurrently with such upfront purchase price payment) last offered by CELGENE in writing to EPIZYME or
(ii) taken as a whole, are materially less favorable to EPIZYME and/or its shareholders, as applicable, than the terms last offered in writing to EPIZYME by CELGENE (such condition, the “Lower Value Third Party Offer
Condition”), then (A) EPIZYME shall, prior to entering into the Proposed Transaction with such Third Party, offer such terms (and in the case of the foregoing clause (i), including the lower upfront purchase price) to CELGENE

  
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(and, if CELGENE accepts such offer, CELGENE shall have the right to substitute an equivalent amount of cash for any non-cash consideration in the Third Party offer), (B) CELGENE shall have
[**] days after the date of receipt of such offer from EPIZYME to notify EPIZYME in writing of its acceptance of such offer and (C) (1) if CELGENE so accepts, the Parties shall promptly enter into a definitive agreement for the Proposed
Transaction on such terms, or (2) if CELGENE does not accept, then EPIZYME shall be free, without any further obligation to CELGENE under this Agreement with respect thereto, to enter into the Proposed Transaction with a Third Party;
provided further that if EPIZYME does not enter into a definitive agreement for a Proposed Transaction with a Third Party within two hundred and twenty five (225) days after the expiration of CELGENE’s ROFN Right as
described above, and at such time the Option Term has not yet expired, CELGENE’s ROFN Right shall be reinstated, the ROFN Expiration shall be deemed not to have previously occurred, and the Parties shall again comply with this Section 7.2
as if the Proposed Transaction were a new transaction. For the avoidance of doubt, preliminary discussions that precede a formal offer or term sheet shall not be restricted by this Section 7.2. This Section 7.2 and the ROFN Right shall
terminate immediately upon the earlier to occur of the termination of the Option Term or consummation of a Business Combination by EPIZYME. 

Any notice provided by either Party hereunder, as well as the fact that this section might be applicable, that a notice has been provided hereunder or
that EPIZYME has considered/is considering a Proposed Transaction, shall be “Confidential Information” of both Parties and expressly subject to Article 9, including Section 9.1, hereof. 

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. 

  
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 (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 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. 

  
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 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. 

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. 

  
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 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 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. 

  
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 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. 

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 

  
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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 Opt-Out pursuant to Section 3.8) 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 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. 

  
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 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 Opt-Out pursuant to Section 3.8), such listings to include all so called
“Orange Book” 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 Opt-Out pursuant to Section 3.8). 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 Opt-Out pursuant Section 3.8) 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 

  
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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 Opt-Out pursuant to Section 3.8) in the EPIZYME Territory and 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, 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: 

  
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 (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;

 (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. 

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, 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 

  
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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. 
 9.3 Press Release; Disclosure of Agreement. 

9.3.1 Press Release. The Parties shall issue a press release, in the form attached as Exhibit D, on April 26, 2012 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). 

  
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 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; 

(e) milestone achievements (but not amounts) 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 Celgene Option by CELGENE with respect to a Selected Target, and (iii) Achievement of Proof of Concept of a Licensed Compound Directed to the applicable Selected
Target, provided that such milestone achievement shall be described as meeting a “predefined clinical milestone”; and 
 (f) election by CELGENE to extend the Option Term and the amount of the Extension Fee. 

Prior to making any such disclosure, the Party proposing such disclosure (the “Proposing Party”) shall provide the other Party
(the “Non-Proposing Party”) with a draft of such proposed disclosure for the Non-Proposing Party’s review. Within [**] Business Days after the Non-Proposing Party’s receipt of such proposed disclosure, the Parties shall
discuss any comments the Non-Proposing 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 Party shall remove any Confidential Information of the Non-Proposing Party that the Non-Proposing 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-Proposing Party’s prior written consent, which shall not be unreasonably withheld or delayed, and
in no event shall the Non-Proposing 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 E and (2) with respect to licensees, sublicensees and collaborators, attached hereto as Exhibit F, 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. 

  
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 (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. 
 9.4 Prior Disclosures of Confidential Information. Any and all Confidential Information (as that
term is defined in the Existing Confidentiality Agreement), in any form, which may have been exchanged between EPIZYME, CELGENE and PARENT prior to the Effective Date, under the Mutual Confidentiality Agreement between EPIZYME and PARENT dated
August 23, 2011 (the “Existing Confidentiality Agreement”), shall be deemed Confidential Information of the applicable Party hereunder and shall be subject to the terms of this Article 9. This Agreement supersedes and replaces
the Existing Confidentiality Agreement. 
 9.5 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. 

9.6 Publications. 
 9.6.1 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 9.6 and Section 9.7, 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 9.6. 
 9.6.2 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 

  
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 (c) an identification of the Reviewing Party’s Confidential Information that is
contained in the material reviewed. 
 Any Confidential Information of the Reviewing Party shall, if requested by the Reviewing Party, be
removed. 
 9.6.3 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. 

9.6.4 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 9.6 to the same extent that CELGENE or EPIZYME (as the case may be) has the right to do so. 

9.6.5 Available Targets Prior to Selection. Subject to Sections 9.6.6(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 9.6, including Section 9.6.2. 
 9.6.6 Exceptions. 
 (a) Epizyme Opt-Out. In the event EPIZYME
exercises its EPIZYME Opt-Out pursuant to Section 3.8, the provisions of this Section 9.6 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 9.7, 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 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 9.6 and (b) otherwise, without being subject to the submission and review procedure set forth in this Section 9.6. 

  
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 (c) General Review Articles on Targets. Subject to Sections 9.6.6(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 9.6. 
 9.7 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; 
 (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 

  
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 (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, 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; 
 (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; 

  
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 (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; 

(i) 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 are necessary for the Development, Manufacture or Commercialization of any Compound (including Licensed Compound) or Licensed Product that is Directed to any Target other than an EPIZYME Reserved Target, or any related Diagnostic
Product; 
 (j) After [**] may no longer select or replace any Target pursuant to the [**] Agreement; and 

(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. 

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; 

  
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 (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; and 

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

  
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 (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, 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; 

  
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 (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 6.8.4(a) shall
apply. 
 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 

  
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 (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. 
 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. 

  
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 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 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. 

  
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 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 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. 

  
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 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. 
 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 

  
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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. 

12.2 Unilateral Termination by CELGENE. 
 12.2.1 Termination of Agreement During Option Term. 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 

  
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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. 
 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 

  
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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 2.2.2(b), 3.2 or 3.6 or EPIZYME’s obligation to use Commercially Reasonable Efforts pursuant to Section 2.2.2(a) 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 2.2.2(b), 3.2 or 3.6, 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 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 

  
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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 6.14) from the date such milestone would have been due in accordance with Section 6.7 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 2.2.2(a) 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. 
 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 

  
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 (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 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. 

  
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 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. 

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. 

  
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 (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
(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. 

(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 2.7.1, 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 2.7.1, (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 

  
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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. 
 (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. 

  
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 (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), 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. 

  
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 (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 5.1.4 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 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 5.1.4 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 5.1.2 and 5.1.3, 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 

  
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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 5.1.4, 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 Section 1.74(z)); 6.4, 6.5 and 6.6 (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 7.2 (if 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 2.2.2(a)(iii)(z), 2.2.3, 2.6, 2.7.4, 2.7.5(d)(2) – (5), inclusive, 2.7.5(e), and 2.7.5(f)); 3 (except for Sections 3.3.1 (except for 3.3.1(ii) and (iii)), 3.5.3(b), and 3.7); 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 

  
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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 5.1.4 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 5.1.2 and 5.1.3 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. 
 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 2.2.2(a)(iii)(z), 2.2.3, 2.6, 2.7.5(d)(2) – (5), inclusive, 2.7.5(e),
and 2.7.5(f); 5.1.4, 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. 

  
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 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. 
 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 

  
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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 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. 

  
 - 113 -

 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 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.

  
 - 114 -

 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 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.
		  	325 Vassar Street
		  	 Cambridge, Massachusetts 02139

Attention: Chief Business Officer
 Telephone:
(617) 500-0712

		  	Facsimile: (617) 349-0707
		
	with a copy to:	  	 WilmerHale LLP
 60 State
Street
 Boston, MA 02109

		  	Attention: David E. Redlick, Esq.
		  	                 Steven D. Barrett, Esq.
		  	Telephone:   (617) 526-6000
		  	Facsimile:    (617) 526-5000

  
 - 115 -

			
		
	If to CELGENE,	  	
		
	addressed to:	  	 Celgene International Sàrl
 Route de Perreux
 12017 Boudry

		  	 Switzerland
 Attention: Chief
Operations Officer
 Telephone: +41 32 729 8500

		  	Facsimile: +41 32 729 8508
		
	with a copy to:	  	 Celgene Legal
 86 Morris
Avenue
 Summit, NJ 07901

		  	 Attention: General Counsel

Telephone: (908) 673-9000
 Facsimile: (908)
673-2771

		
	with a copy to:	  	 Dechert LLP
 902 Carnegie
Center
 Suite 500

		  	Princeton, NJ 08540
		  	Attention:        James J. Marino
		  	
                        David E.
Schulman
 Telephone:      (609) 955-3230

		  	Facsimile:       (609) 873-9138

 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. 

  
 - 116 -

 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 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

  
 - 117 -

 
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 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, with respect to 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)

  
 - 118 -

 
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. 

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] 

  
 - 119 -

 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 International Sàrl
		
	By:	 	/s/ Robert J. Hugin
		 	 Name: Robert J. Hugin

Title: Managing Officer

		
	By:	 	/s/ Paul D’Angio
		 	 Name: Paul D’Angio
 Title: Managing Officer

	
	Celgene Corporation (solely for the purposes of Section 13.21)
		
	By:	 	/s/ Robert J. Hugin
		 	 Name: Robert J. Hugin

Title: Chief Executive Officer

 [Signature page to Collaboration and License Agreement] 

 EXHIBIT A 

Initial Research Plan 
 See attached. 

  
 A-1

 Epizyme, Inc. 

General Discovery Activities by Stage 
 Target Validation: [**]. 
 Target-to-Hit: [**]. 

Hit-to-Lead: [**]. 

Lead-to-Candidate: [**]. 

Candidate-to-IND: [**]. 

  
 A-2

 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 International Sàrl, pursuant to that certain Collaboration and License Agreement, entered into among Epizyme, Inc., Celgene International Sàrl and Celgene Corporation,
with an Effective Date of April 2, 2012 (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 INTERNATIONAL SÀRL:	    	For EPIZYME, INC.
				
	By:	 	  
	    	By:	 	  

				
	Name:	 	  
	    	Name:	 	  

				
	Title	 	Alliance Manager	    	Title:	 	Chief Scientific Officer

  
 B-1

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

  
 C-1

 EXHIBIT D 

Press Release 
 See attached. 

  
 D-1

 

 
 Epizyme Forms Strategic Partnership with Industry Leader in Epigenetic 

Therapies, Celgene Corporation, to Develop Personalized Therapeutics for 

Genetically-Defined Cancers 
 – Partnership Leverages Epizyme’s Transformational Histone Methyltransferase 
 Inhibitor Platform and Celgene’s Translational Research Capabilities – 
 – New Alliance Reflects Joint Commitment to Advance Human Health Through Bold 
 Pursuits in Epigenetic-Based Therapies – 
 CAMBRIDGE, Mass. and
SUMMIT, N.J. – April 26, 2012 – Epizyme and Celgene International Sàrl, a subsidiary of Celgene Corporation (NASDAQ: CELG) today announced the formation of a strategic partnership to discover, develop and commercialize
personalized therapeutics for patients with genetically-defined cancers by inhibiting histone methyltransferases (HMTs), an important epigenetic target class. 
 Under the terms of the agreement, Celgene receives the exclusive option to license ex-US rights to Epizyme’s available HMT inhibitor programs during an initial three-year period and has the right to
extend this option period for one year with additional funding. Epizyme and Celgene will work jointly to discover and develop HMT inhibitors and will co-fund global development of the collaboration programs. 

The collaboration leverages the transformational science of Epizyme’s HMT inhibitor platform and includes Epizyme’s DOT1L HMT inhibitor
program, to which Celgene licenses the ex-US rights at signing. DOT1L is an oncogenic driver gene in a subtype of acute leukemias called Mixed Lineage Leukemia (MLL). The DOT1L program is currently in pre-clinical development. 

Epizyme retains all US rights to the collaboration programs and receives a $90 million upfront payment, which includes an equity investment. For each HMT
inhibitor that Celgene licenses, Epizyme is eligible to earn more than $160 million in milestone payments and up to double digit royalties on ex-US sales. 
 “Celgene is a leader in epigenetic therapies for cancer through our existing drugs, and continues to focus on delivering new drugs with high therapeutic impact in this area,” said Thomas Daniel,
M.D., President of Research for Celgene. “Epizyme’s platform, scientific leadership in histone methyltransferases, and leading position on promising HMT targets offers an exciting complementary approach. Our collaboration with Epizyme is a
key element of our strategy to develop new and innovative therapeutic paradigms.” 

  
 D-2

 

 
 “Our Celgene partnership is a transformational step in Epizyme’s growth and is made possible by
Celgene’s vision and commitment to patients,” said Robert Gould, Ph.D., CEO and President of Epizyme. “Through this collaboration, Epizyme gains access to Celgene’s leading drug development resources, enabling us to substantially
increase the breadth and depth of our efforts while retaining US rights to our pipeline of personalized therapeutics.” 
 About HMTs

 The HMT class of epigenetic enzymes contains 96 members, many of which have strong genetic associations with cancer and other serious
diseases. Targeting HMTs with potent and selective small molecule inhibitors offers an innovative therapeutic approach to controlling pathways of disease-causing gene expression. 
 About Epizyme 
 Epizyme is leading the discovery and development of small molecule histone
methyltransferase (HMT) inhibitors, a new class of personalized therapeutics for the treatment of patients with genetically-defined cancers, based on breakthroughs in the field of epigenetics. Genetic alterations in the HMTs are strongly associated
with the underlying causes of multiple human diseases, including cancer. Epizyme’s patient-driven approach represents the future of personalized therapeutics by creating better medicines for the right patients more quickly and at lower cost
than traditional approaches. www.epizyme.com 
 About Celgene International Sàrl 

Celgene International Sàrl, located in Boudry, in the Canton of Neuchâtel, Switzerland, is a wholly owned subsidiary and international
headquarters of Celgene Corporation. Celgene Corporation, headquartered in Summit, New Jersey, is an integrated global pharmaceutical company engaged primarily in the discovery, development and commercialization of innovative therapies for the
treatment of cancer and inflammatory diseases through gene and protein regulation. For more information, please visit the Company’s website at www.celgene.com. 
 Celgene Forward-Looking Statements 
 This press release contains forward-looking
statements, which are generally statements that are not historical facts. Forward-looking statements can be identified by the words “expects,” “anticipates,” “believes,” “intends,” “estimates,”
“plans,” “will,” “outlook” and similar expressions. Forward-looking statements are based on management’s current plans, estimates, assumptions and projections, and speak only as of the date they are made. We
undertake no obligation to update any forward-looking statement in light of new information or future events, except as otherwise required by law. Forward-looking statements involve inherent risks and uncertainties, most of which are difficult to
predict and are generally beyond our control. Actual results or outcomes may differ materially from those implied by the forward-looking statements as a result of the impact of a number of factors, many of which are discussed in more detail in our
Annual Report on Form 10-K and our other reports filed with the Securities and Exchange Commission. 

  
 D-3

 EXHIBIT E 

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

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

  
 E-1

 EXHIBIT F 

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

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

  
 F-1

 SCHEDULE 1.33 

Development Candidate Selection Criteria 
 Confidential Materials omitted and filed separately with the Securities and Exchange Commision. A total of two pages were omitted. [**] 

  
 S 1.33 - 1

 SCHEDULE 1.50 

EPIZYME Reserved Targets 

[**] 

  
 S 1.50 - 1

 SCHEDULE 1.73 

Lead Candidate Criteria 

Confidential Materials omitted and filed separately with the Securities and Exchange Commision. A total of one page was omitted. [**] 

  
 S 1.73 - 1

 SCHEDULE 1.89 

[**] 
  

																			
	 Official Symbol*
	  	 Official Full Name
	  	KMT Name	 	  	Alternate Names	 	  	Entrez Gene
ID	 	  	RefSeq	 
	 [**]
	  	[**]	  	 	[**]	  	  	 	[**]	  	  	 	[**]	  	  	 	[**]	  
	 [**]
	  	[**]	  				  	 	[**]	  	  	 	[**]	  	  	 	[**]	  
	 [**]
	  	[**]	  				  	 	[**]	  	  	 	[**]	  	  	 	[**]	  
						
	 [**]
	  		  				  				  				  			

  
 S 1.89 - 1

 SCHEDULE 10.2(a) 

EPIZYME Patents 
  

																							
	 Origin
	 	 Country
	 	 Title
	  	Inventor
List	  	Appl’n
Status	  	Serial
Number	  	Filing
Date	  	Publication
Number	  	Publication
Date	  	Patent
Number	  	Issue
Date	  	Expiration
Date

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

  
 S 10.2(a) - 1

 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 

  
 S 10.2(b) - 1

 SCHEDULE 13.14 

Key Employees 
 EPIZYME
EMPLOYEES: 
 [**] 
 CELGENE
EMPLOYEES: 
 [**] 

  
 S 13.14 - 1

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