X0306 4 2019-08-19 0 0001571498 Epizyme, Inc. EPZM 0001707648 TOMBESI PAOLO C/O EPIZYME, INC., 400 TECHNOLOGY SQUARE CAMBRIDGE MA 02139 0 1 0 0 Chief Financial Officer Stock Option (Right to Buy) 13.86 2019-08-19 4 A 0 132225 0.00 A 2029-08-18 Common Stock 132225 132225 D Restricted Stock Units 2019-08-19 4 A 0 28217 0.00 A Common Stock 28217 28217 D This option was granted on August 19, 2019 pursuant to the Company's 2013 Stock Incentive Plan with respect to 132,225 shares of Epizyme, Inc. common stock, with 25% vesting on August 19, 2020 and the remaining 75% vesting in 36 substantially equal monthly installments thereafter. Each restricted stock unit represents the contingent right to receive one share of Epizyme, Inc. common stock upon vesting. This award, granted on August 19, 2019, pursuant to the Company's 2013 Stock Incentive Plan, vests in four equal annual installments beginning August 19, 2020. Vested shares will be delivered to the reporting person. /s/ Paolo Tombesi 2019-08-21