Editas Medicine, Inc. — Director's Dealing 2016

Feb 3, 2016

SEC Form 3 — Initial Statement of Beneficial Ownership

Issuer: Editas Medicine, Inc. (EDIT)
CIK: 0001650664
Period of Report: 2016-02-02

Reporting Person: Flynn James E (10% Owner, Possible Member of 10% Group)
Reporting Person: Deerfield Mgmt III, L.P. (10% Owner, Possible Member of 10% Group)
Reporting Person: DEERFIELD MANAGEMENT CO (10% Owner, Possible Member of 10% Group)
Reporting Person: Deerfield Private Design Fund III, L.P. (10% Owner, Possible Member of 10% Group)
Reporting Person: Deerfield Healthcare Innovations Fund, L.P. (10% Owner, Possible Member of 10% Group)
Reporting Person: Deerfield Mgmt HIF, L.P (10% Owner, Possible Member of 10% Group)

Holdings (Derivative)

Security	Exercise Price	Expiration	Underlying	Shares	Ownership
Series B Preferred Stock	$		Common Stock (854700)		Indirect
Series B Preferred Stock	$		Common Stock (854700)		Indirect

Footnotes

F1: The Series B Preferred Stock will automatically convert upon closing of the Issuer's initial public offering into Issuer's common stock.

F2: Amount reflects a 1-for-2.6 reverse stock split effected by the Issuer on January 15, 2016.

F3: This Form 3 is being filed by the undersigned as well as the entities listed on the Joint Filer Information Statement attached as an exhibit hereto (the "Reporting Persons"). Deerfield Mgmt III, L.P. is the general partner of Deerfield Private Design Fund III, L.P. ("Fund III"). Deerfield Mgmt HIF, L.P. is the general partner of Deerfield Healthcare Innovations Fund, L.P. (collectively with Fund III, the "Funds"). Deerfield Management Company, L.P. is the investment manager of the Funds. James E. Flynn is the sole member of the general partner of each of Deerfield Mgmt III, L.P., Deerfield Mgmt HIF, L.P. and Deerfield Management Company, L.P. In accordance with Instruction 5 (b)(iv) to Form 3, the entire amount of the Issuer's securities held by the Funds is reported herein.

F4: For purposes of Section 16 of the Securities Exchange Act of 1934, as amended, each Reporting Person disclaims beneficial ownership of any such securities, except to the extent of his/its indirect pecuniary interest therein, if any, and this report shall not be deemed an admission that such Reporting Person is the beneficial owner of such securities for purposes of Section 16 or otherwise.