X0306 4 2016-12-09 0 0001571498 Epizyme, Inc. EPZM 0001632720 Singer Andrew E. C/O EPIZYME, INC. 400 TECHNOLOGY SQUARE CAMBRIDGE MA 02139 0 1 0 0 EVP & CFO Common Stock, par value $0.0001 2016-12-09 4 M 0 1682 A 32060 D Common Stock, par value $0.0001 2016-12-09 4 M 0 777 A 32837 D Common Stock, par value $0.0001 2016-12-09 4 S 0 1013 11.0286 D 31824 D Restricted Stock Units 0.00 2016-12-09 4 M 0 1682 0.00 D Common Stock 1682 43729 D Restricted Stock Units 0.00 2016-12-09 4 M 0 777 0.00 D Common Stock 777 20211 D Each restricted stock unit represents the contingent right to receive one share of Epizyme, Inc. common stock upon vesting. The sale reported on this Form 4 was effected pursuant to a Rule 10b5-1 plan adopted by the Reporting Person to cover taxes associated with the vesting of his restricted stock. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $10.65 per share to $11.30 per share, inclusive. The Reporting Person undertakes to provide the Issuer, any security holder of the Issuer or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote. This award, granted on February 9, 2016, pursuant to the Company's 2013 Stock Incentive plan, vests as to 25% of the total award on February 9, 2016, a year from the commencement of employment, with the remaining 75% vesting in 36 substantially equal monthly installments thereafter. Vested shares will be delivered to the reporting person. This award, granted on February 9, 2015, pursuant to the Company's 2013 Stock Inventive Plan, vests as to 25% of the total award on February 9, 2016, with the remaining 75% vesting in 36 substantially equal monthly installments thereafter. Vested shares will be delivered to the reporting person. /s/ Adriana Sullivan, attorney-in-fact 2016-12-12