Ownership Submission
FORM 3
UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940
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(Print or Type Responses)
1. Name and Address of Reporting Person *
  EVNIN LUKE
2. Date of Event Requiring Statement (Month/Day/Year)
05/30/2013
3. Issuer Name and Ticker or Trading Symbol
Epizyme, Inc. [EPZM]
(Last)
(First)
(Middle)
C/O MPM ASSET MANAGEMENT, 200 CLARENDON STREET, 54TH FLOOR
4. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
_____ Director __X__ 10% Owner
_____ Officer (give title below) _____ Other (specify below)
5. If Amendment, Date Original Filed(Month/Day/Year)
(Street)

BOSTON, MA 02116
6. Individual or Joint/Group Filing(Check Applicable Line)
___ Form filed by One Reporting Person
_X_ Form filed by More than One Reporting Person
(City)
(State)
(Zip)
Table I - Non-Derivative Securities Beneficially Owned
1.Title of Security
(Instr. 4)
2. Amount of Securities Beneficially Owned
(Instr. 4)
3. Ownership Form: Direct (D) or Indirect (I)
(Instr. 5)
4. Nature of Indirect Beneficial Ownership
(Instr. 5)
Common Stock 178,331 (1)
I
See Footnote (2)

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly. SEC 1473 (7-02)
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Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security
(Instr. 4)
2. Date Exercisable and Expiration Date
(Month/Day/Year)
3. Title and Amount of Securities Underlying Derivative Security
(Instr. 4)
4. Conversion or Exercise Price of Derivative Security 5. Ownership Form of Derivative Security: Direct (D) or Indirect (I)
(Instr. 5)
6. Nature of Indirect Beneficial Ownership
(Instr. 5)
Date Exercisable Expiration Date Title Amount or Number of Shares
Series A Preferred Stock   (3)   (3) Common Stock 2,309,998 $ (3) I See Footnote (4)
Series B Preferred Stock   (5)   (5) Common Stock 392,156 $ (5) I See Footnote (6)

Reporting Owners

Reporting Owner Name / Address Relationships
Director 10% Owner Officer Other
EVNIN LUKE
C/O MPM ASSET MANAGEMENT
200 CLARENDON STREET, 54TH FLOOR
BOSTON, MA 02116
    X    
GADICKE ANSBERT
C/O MPM ASSET MANAGEMENT
200 CLARENDON STREET, 54TH FLOOR
BOSTON, MA 02116
    X    

Signatures

/s/ Luke Evnin 05/30/2013
**Signature of Reporting Person Date

/s/ Ansbert Gadicke 05/30/2013
**Signature of Reporting Person Date

Explanation of Responses:

* If the form is filed by more than one reporting person, see Instruction 5(b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
(1) Reflects a one-for-three reverse stock split effected May 13, 2013.
(2) The shares are held as follows: 166,007 by MPM BioVentures IV-QP, L.P. ("BV IV QP"), 6,395 by MPM BioVentures IV GmbH & Co. Beteiligungs KG ("BV IV KG"), 4,720 by MPM Asset Management Investors BV4 LLC ("AM BV4") and 1,209 shares held by MPM BioVentures IV Strategic Fund, L.P. ("BV IV SF"). MPM BioVentures IV GP LLC and MPM BioVentures IV LLC ("BV LLC") are the direct and indirect general partners of BV IV QP, BV IV KG and BV IV SF and BV LLC is the manager of AM BV4. Ansbert Gadicke, Luke Evnin, Vaughn M. Kailian,James Paul Scopa, Todd Foley and John Vander Vort are the members of BV LLC. Each Reporting Person disclaims beneficial ownership of the securities except to the extent of his or its respective pecuniary interest therein.
(3) Each share of Series A Preferred Stock is convertible into 1/3rd of a share of Common Stock without payment of further consideration and will automatically convert into 1/3rd of a share of Common Stock upon the closing of the Issuer's initial public offering without payment of further consideration. The shares have no expiration date.
(4) The shares are held as follows: 1,850,799 by BV IV QP, 71,303 by BV IV KG, 52,628 by AM BV4 and 335,268 shares held by BV IV SF. Each Reporting Person disclaims beneficial ownership of the securities except to the extent of his or its respective pecuniary interest therein.
(5) Each share of Series B Preferred Stock is convertible into 1/3rd of a share of Common Stock without payment of further consideration and will automatically convert into 1/3rd of a share of Common Stock upon the closing of the Issuer's initial public offering without payment of further consideration. The shares have no expiration date.
(6) The shares are held as follows: 312,152 by BV IV QP, 12,026 by BV IV KG, 8,876 by AM BV4 and 59,102 shares held by BV IV SF. Each Reporting Person disclaims beneficial ownership of the securities except to the extent of his or its respective pecuniary interest therein.
 
Remarks:
See Form 3 for MPM BioVentures IV-QP, L.P. for additional members of this joint filing.

Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, See Instruction 6 for procedure.

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