X0306 4 2020-02-03 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 2020-02-03 4 A 0 12856 0.00 A 71659 D Stock Option (Right to Buy) 21.39 2020-02-03 4 A 0 61834 0.00 A 2030-02-02 Common Stock 61834 61834 D Consists of shares of Common Stock issuable under 12,856 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 February 3, 2021. This option was granted on February 3, 2020 pursuant to the Company's 2013 Stock Incentive Plan with respect to 61,834 shares of Common Stock, with 25% vesting on February 3, 2021 and the remaining 75% vesting in 36 substantially equal monthly installments thereafter. /s/ John Weidenbruch, attorney-in-fact 2020-02-05