X0206 3 2013-05-30 0 0001571498 Epizyme, Inc. EPZM 0001577021 Copeland Robert A C/O EPIZYME, INC. 400 TECHNOLOGY SQUARE CAMBRIDGE MA 02139 0 1 1 0 EVP and CSO Common Stock 56694 D Common Stock 33333 I By Wife Stock Option (right to buy) 0.51 2020-03-17 Common Stock 60000 D Stock Option (right to buy) 0.60 2021-03-10 Common Stock 109764 D Stock Option (right to buy) 2.19 2022-10-02 Common Stock 54410 D Stock Option (right to buy) 3.54 2023-01-24 Common Stock 94000 D Reflects a one-for-three reverse stock split effected on May 13, 2013. This option was granted on March 18, 2010 with respect to 60,000 shares of Common Stock, with 25% vesting on March 18, 2011 and the remaining 75% vesting in 36 substantially equal monthly installments thereafter. This option was granted on March 11, 2011 with respect to 109,764 shares of Common Stock, with 25% vesting on March 11, 2012 and the remaining 75% vesting in 36 substantially equal monthly installments thereafter. This option is fully vested. This option was granted on January 25, 2013 with respect to 94,000 shares of Common Stock, with 25% vesting on January 25, 2014 and the remaining 75% vesting in 36 substantially equal monthly installments thereafter. /s/ Stephen Garbacz, attorney-in-fact 2013-05-30