EPIZYME, INC. NON-EMPLOYEE DIRECTOR COMPENSATION PROGRAM

Annual Fee. An annual fee of $35,000 relating to such director’s service on the Board.

Initial Option Grant. If the non-employee director is serving on the Board upon the closing of the public offering of the Company’s common stock, $0.0001 par value per share (the “Common Stock”), an initial stock option grant pursuant to the Company’s 2013 Stock Incentive Plan, as it may be amended from time to time (the “Plan”), to purchase 17,666 shares of Common Stock. Subject to the non-employee director’s continued service as a director, such option shall vest concurrently with the expiration of the initial terms of office for the class in which each such director serves, and, in the event of a change in control of the Company, the vesting schedule of the option will accelerate in full. The exercise price of such option will be equal to the fair market value of the Common Stock on the date of grant.

Option Grant Upon Initial Election. If the non-employee director is elected to the Board after the closing of the public offering of the Company’s Common Stock, an initial stock option grant pursuant to the Plan to purchase 17,666 shares of Common Stock upon his or her election to the Board. Subject to the non-employee director’s continued service as a director, such option shall vest as to 25% of the shares of Common Stock underlying such option on the first anniversary of the grant date and with respect to an additional 2.0833% of the shares at the end of each successive month period following the first anniversary of the grant date until the fourth anniversary of the grant date and, in the event of a change in control of the Company, the vesting schedule of the option will accelerate in full. The exercise price of such option will be equal to the fair market value of the Common Stock on the date of grant.

Annual Option Grant. If a non-employee director has served on the Board for at least six months, a stock option grant pursuant to the Plan to purchase 7,333 shares of Common Stock on the date of the first Board meeting held after each annual meeting of stockholders. Unless otherwise provided at the time of grant, subject to the non-employee director’s continued service as a director, the option will vest with respect to all of the shares of Common Stock underlying the option on the first anniversary of the grant date and, in the event of a change in control of the Company, the vesting schedule of the option will accelerate in full. The exercise price of the option will be equal to the fair market value of the Common Stock on the date of grant.

An annual fee of $7,000 for serving on the Audit Committee of the Board (the “Audit Committee”), except that the non-employee director who serves as the chairman of the Audit Committee shall receive an additional annual fee of $8,000.

An annual fee of $5,000 for serving on the Compensation Committee of the Board (the “Compensation Committee”), except that the non-employee director who serves as the chairman of the Compensation Committee shall receive an additional annual fee of $5,000.

An annual fee of $2,500 for serving on any other committee of the Board other than the Audit Committee and the Compensation Committee, except that the non-employee director who serves as the chairman of such other committee shall receive an additional annual fee of $2,500.