X0306 4/A 2019-12-02 2019-12-06 0 0001571498 Epizyme, Inc. EPZM 0001746830 Agarwal Shefali C/O EPIZYME, INC., 400 TECHNOLOGY SQUARE CAMBRIDGE MA 02139 0 1 0 0 Chief Medical Officer Common Stock 2019-12-02 4 A 0 22577 0.00 A 58276 D Stock Option (Right to Buy) 15.76 2019-12-02 4 A 0 34978 0.00 A 2029-12-01 Common Stock 34978 34978 D Consists of shares of Common Stock issuable under 22,577 restricted stock units ("RSUs") granted pursuant to the Company's 2013 Stock Incentive Plan. Each RSU represents the right to receive one share of Common Stock upon vesting. These RSUs are scheduled to vest in four equal annual installments over four years from the grant date, with the first installment vesting on December 2, 2020. This option was granted on December 2, 2019 pursuant to the Company's 2013 Stock Incentive Plan with respect to 34,978 shares of Common Stock, with 25% vesting on December 2, 2020 and the remaining 75% vesting in 36 substantially equal monthly installments thereafter. This amendment is being filed solely to correct the exercrise price of the stock option grant reported on the reporting person's Form 4 filed on December 6, 2019. The exercise price should have been reported as $15.76 per share, the closing price of the Company's Common Stock on the date of grant. /s/John Weidenbruch, attorney-in-fact 2020-01-06