X0306 4 2020-01-23 0 0001571498 Epizyme, Inc. EPZM 0001766032 Beaulieu Joseph C/O EPIZYME, INC., 400 TECHNOLOGY SQUARE CAMBRIDGE MA 02139 0 1 0 0 Corporate Controller Common Stock, par value $0.0001 2020-01-23 4 A 0 875 A 1372 D Common Stock, par value $0.0001 2020-01-24 4 S 0 330 24.63 D 1042 D Represents common stock issued upon vesting of restricted stock units granted under the issuer's 2013 Stock Incentive Plan that vested upon the issuer's achievement of a specified performance target. The transaction date represents the date on which the issuer's Compensation Committee determined that the performance target was achieved. Represents shares automatically sold by the reporting person to satisfy tax withholding obligations in connection with the vesting of the restricted stock units described in footnote 1. The automatic sale of the reporting person's shares is provided for in a restricted stock unit agreement constituting a "binding contract" consistent with the affirmative defense to liability under Rule 10b5-1 and the sale does not represent a discretionary trade by the reporting person. /s/John Weidenbruch, attorney-in-fact 2020-01-27