EPIZYME, INC. Restricted Stock Agreement

Exhibit 10.8

EPIZYME, INC.

Restricted Stock Agreement

Epizyme, Inc. (the “Company”) has selected you to receive the restricted stock award described above, which is subject to the provisions of the Company’s 2013 Stock Incentive Plan (the “Plan”) and the terms and conditions contained in this Restricted Stock Agreement. Please confirm your acceptance of this restricted stock award and of the terms and conditions of this Agreement by signing a copy of this Agreement where indicated below.

EPIZYME, INC.

Restricted Stock Agreement

The terms and conditions of the award of shares of restricted common stock of the Company (the “Restricted Shares”) made to the Recipient, as set forth on the cover page of this Agreement, are as follows:

(a) The Restricted Shares are issued to the Recipient, effective as of the Grant Date (as set forth on the cover page of this Agreement), in consideration of employment services rendered and to be rendered by the Recipient to the Company.

(b) The Restricted Shares will initially be issued by the Company in book entry form only, in the name of the Recipient. Following the vesting of any Restricted Shares pursuant to Section 2 below, the Company shall, if requested by the Recipient, issue and deliver to the Recipient a certificate representing the vested Restricted Shares. The Recipient agrees that the Restricted Shares shall be subject to the forfeiture provisions set forth in Section 3 of this Agreement and the restrictions on transfer set forth in Section 4 of this Agreement

(a) Vesting Schedule. Unless otherwise provided in this Agreement or the Plan, the Restricted Shares shall vest in accordance with the following vesting schedule: 25% of the total number of Restricted Shares shall vest on the first anniversary of the Grant Date and 25% of the total number of Restricted Shares shall vest at the end of each successive one-year period following the first anniversary of the Grant Date, through and including the fourth anniversary of the Grant Date. Any fractional number of Restricted Shares resulting from the application of the foregoing percentages shall be rounded down to the nearest whole number of Restricted Shares.

(b) Acceleration of Vesting. Notwithstanding the foregoing vesting schedule, all unvested Restricted Shares shall vest effective immediately upon (i) the termination by the Company of the Recipient’s employment without Cause (as defined below) within the one-year period following a Change in Control (as defined below) or (ii) the death or Disability (as defined below) of the Recipient.

(c) Definitions. For purposes of this Agreement:

(i) “Disability” means: (A) if the Recipient’s employment with the Company is subject to the terms of an employment agreement between the Recipient and the Company, which employment agreement includes a definition of “Disability”, the term “Disability” as used in this Agreement shall have the meaning set forth in such employment agreement during the period that such employment agreement remains in effect; (B) in the absence of such an agreement, the term “Disability” as used in the Company’s long-term disability plan, if any; or (C) if neither clause (A) nor clause (B) is applicable, a physical or mental infirmity which impairs the Recipient’s ability to substantially perform his or her duties for a period of 180 consecutive days.

(ii) “Change in Control” means the occurrence of any of the following events: (i) any merger or consolidation that results in the voting securities of the Company outstanding immediately prior thereto representing (either by remaining outstanding or by being converted into voting securities of the surviving or acquiring entity) less than 50% of the combined voting power of the voting securities of the Company or such surviving or acquiring entity outstanding immediately after such merger or consolidation; (ii) any sale of all or substantially all of the assets of the Company; (iii) the complete liquidation or dissolution of the Company; or (iv) the acquisition of “beneficial ownership” (as defined in Rule 13d-3 under the Securities Exchange Act of 1934, as amended (the “Exchange Act”)) of securities of the Company representing 50% or more of the combined voting power of the Company’s then outstanding securities (other than through a merger or consolidation or an acquisition of securities directly from the Company) by any “person,” as such term is used in Sections 13(d) and 14(d) of the Exchange Act, other than the Company, any trustee or other fiduciary holding securities under an employee benefits plan of the Company or any corporation owned directly or indirectly by the stockholders of the Company in substantially the same proportion as their ownership of stock of the Company.

(iii) “Cause” shall exist upon (i) a good faith finding by the Board of Directors of the Company (A) of repeated and willful failure of the Recipient after written notice to perform his or her reasonably assigned duties for the Company, or (B) that the Recipient has engaged in dishonesty, gross negligence or misconduct, which dishonesty, gross negligence or misconduct has had a material adverse effect on the business or affairs of the Company; (ii) the conviction of the Recipient of, or the entry of a pleading of guilty or nolo contendere by the Recipient to, any crime involving moral turpitude or any felony; or (iii) a breach by the Recipient of any material provision of any invention and non-disclosure agreement or non-competition and non-solicitation agreement with the Company.

In the event that the Recipient ceases to be employed by the Company for any reason or no reason, with or without cause [(except as provided in Section 2(b) above)], all of the Restricted Shares that are unvested as of the time of such employment termination shall be forfeited immediately and automatically to the Company, without the payment of any consideration to the Recipient, effective as of such termination of employment. The Recipient shall have no further rights with respect to any Restricted Shares that are so forfeited. If the Recipient is employed by a subsidiary of the Company, any references in this Agreement to employment with the Company shall instead be deemed to refer to employment with such subsidiary.

The Recipient shall not sell, assign, transfer, pledge, hypothecate or otherwise dispose of, by operation of law or otherwise (collectively “transfer”) any Restricted Shares, or any interest therein, until such Restricted Shares have vested, except that the Recipient may transfer such

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Restricted Shares: (a) to or for the benefit of any spouse, children, parents, uncles, aunts, siblings, grandchildren and any other relatives approved by the Compensation Committee (collectively, “Approved Relatives”) or to a trust established solely for the benefit of the Recipient and/or Approved Relatives, provided that such Restricted Shares shall remain subject to this Agreement (including without limitation the forfeiture provisions set forth in Section 3 and the restrictions on transfer set forth in this Section 4) and such permitted transferee shall, as a condition to such transfer, deliver to the Company a written instrument confirming that such transferee shall be bound by all of the terms and conditions of this Agreement; or (b) as part of the sale of all or substantially all of the shares of capital stock of the Company (including pursuant to a merger or consolidation). The Company shall not be required (i) to transfer on its books any of the Restricted Shares which have been transferred in violation of any of the provisions of this Agreement or (ii) to treat as owner of such Restricted Shares or to pay dividends to any transferee to whom such Restricted Shares have been transferred in violation of any of the provisions of this Agreement.

The book entry account reflecting the issuance of the Restricted Shares in the name of the Recipient shall bear a legend or other notation upon substantially the following terms:

“These shares of stock are subject to forfeiture provisions and restrictions on transfer set forth in a certain Restricted Stock Agreement between the corporation and the registered owner of these shares (or his or her predecessor in interest), and such Agreement is available for inspection without charge at the office of the Secretary of the corporation.”

Except as otherwise provided in this Agreement, for so long as the Recipient is the registered owner of the Restricted Shares, the Recipient shall have all rights as a shareholder with respect to the Restricted Shares, whether vested or unvested, including, without limitation, rights to vote the Restricted Shares and act in respect of the Restricted Shares at any meeting of shareholders; provided that, as provided in the Plan, the payment of dividends on unvested Restricted Shares shall be deferred until after such shares vest.

This Agreement is subject to the provisions of the Plan, a copy of which is furnished to the Recipient with this Agreement.

(a) Acknowledgments; Section 83(b) Election. The Recipient acknowledges that he or she is responsible for obtaining the advice of the Recipient’s own tax advisors with respect to the acquisition of the Restricted Shares and the Recipient is relying solely on such advisors and not on any statements or representations of the Company or any of its agents with respect to the tax consequences relating to the Restricted Shares. The Recipient understands that the Recipient (and not the Company) shall be responsible for the Recipient’s tax liability that may arise in connection with the acquisition, vesting and/or disposition of the Restricted Shares.

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The Recipient acknowledges that he or she has been informed of the availability of making an election under Section 83(b) of the Internal Revenue Code, as amended, with respect to the issuance of the Restricted Shares and understands that it is a condition to receipt of this Award that the Recipient not file a Section 83(b) election.

(b) Withholding. The Recipient acknowledges and agrees that the Company has the right to deduct from payments of any kind otherwise due to the Recipient any federal, state, local or other taxes of any kind required by law to be withheld with respect to the vesting of the Restricted Shares. On each date on which Restricted Shares vest, the Company shall deliver written notice to the Recipient of the amount of withholding taxes due with respect to the vesting of the Restricted Shares that vest on such date; provided, however, that the total tax withholding cannot exceed the Company’s minimum statutory withholding obligations (based on minimum statutory withholding rates for federal and state tax purposes, including payroll taxes, that are applicable to such supplemental taxable income). The Recipient shall satisfy such tax withholding obligations by making a cash payment to the Company on the date of vesting of the Restricted Shares, in the amount of the Company’s withholding obligation in connection with the vesting of such Restricted Shares or by another method permitted under the Plan.

(a) Authority of Compensation Committee. In making any decisions or taking any actions with respect to the matters covered by this Agreement, the Compensation Committee shall have all of the authority and discretion, and shall be subject to all of the protections, provided for in the Plan. All decisions and actions by the Compensation Committee with respect to this Agreement shall be made in the Compensation Committee’s discretion and shall be final and binding on the Recipient.

(b) No Right to Continued Employment. The Recipient acknowledges and agrees that, notwithstanding the fact that the vesting of the Restricted Shares is contingent upon his or her continued employment by the Company, this Agreement does not constitute an express or implied promise of continued employment or confer upon the Recipient any rights with respect to continued employment by the Company.

(c) Governing Law. This Agreement shall be construed, interpreted and enforced in accordance with the internal laws of the State of Delaware without regard to any applicable conflicts of laws provisions.

(d) Recipient’s Acknowledgments. The Recipient acknowledges that he or she has read this Agreement, has received and read the Plan, and understands the terms and conditions of this Agreement and the Plan.

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