Washington, D.C. 20549


Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940
OMB Number: 3235-0287
Estimated average burden
hours per response: 0.5
Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).
1. Name and Address of Reporting Person*

(Last) (First) (Middle)


(City) (State) (Zip)
2. Issuer Name and Ticker or Trading Symbol
Editas Medicine, Inc. [ EDIT ]
5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
X Director 10% Owner
X Officer (give title below) Other (specify below)
3. Date of Earliest Transaction (Month/Day/Year)
4. If Amendment, Date of Original Filed (Month/Day/Year)
6. Individual or Joint/Group Filing (Check Applicable Line)
X Form filed by One Reporting Person
Form filed by More than One Reporting Person
Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3) 2. Transaction Date (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4)
Code V Amount (A) or (D) Price
Common Stock 03/02/2021 P 25,000 A $46.272(1) 35,000 D
Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3) 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (Month/Day/Year) 3A. Deemed Execution Date, if any (Month/Day/Year) 4. Transaction Code (Instr. 8) 5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 6. Date Exercisable and Expiration Date (Month/Day/Year) 7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4) 8. Price of Derivative Security (Instr. 5) 9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4) 10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 11. Nature of Indirect Beneficial Ownership (Instr. 4)
Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares
Stock Option (right to buy) $45.69 03/02/2021 A 196,637 (2) 03/01/2031 Common Stock 196,637 $0 196,637 D
Explanation of Responses:
1. This transaction was executed in multiple trades at prices ranging from $46.27 to $46.44. The price reported above reflects the weighted average purchase price. The Reporting Person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transaction was effected.
2. This option was granted on March 2, 2021 and is scheduled to vest as to one-third of the shares underlying the option when the closing price of the Issuer's common stock, as reported on the Nasdaq Global Select Market, has for 15 consecutive trading days in the five year period following the grant date equaled or exceeded $80.00, $100.00 and $120.00 per share, respectively.
/s/ James C. Mullen 03/04/2021
** Signature of Reporting Person Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (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).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.

     Know all by these present, that the undersigned hereby
makes, constitutes and appoints each of Michelle Robertson,
Charlene Stern-Dombal, Damien Grierson and Erica Iorio, signing
singly and each acting individually, as the undersigned's true
and lawful attorney-in-fact with full power and authority as
hereinafter described to:

      (1)     execute for and on behalf of the undersigned, in
the undersigned's capacity as a director, officer and/or
stockholder of Editas Medicine, Inc. (the "Company"), Forms 3, 4,
and 5 (including any amendments thereto) in accordance with
Section 16(a) of the Securities Exchange Act of 1934 and the
rules thereunder (the "Exchange Act");

      (2)     do and perform any and all acts for and on behalf
of the undersigned which may be necessary or desirable to
prepare, complete and execute any such Form 3, 4, or 5, prepare,
complete and execute any amendment or amendments thereto, and
timely deliver and file such form with the United States
Securities and Exchange Commission (the "SEC") and any stock
exchange or similar authority, including without limitation the
filing of a Form ID or any other application materials to enable
the undersigned to gain or maintain access to the Electronic Data
Gathering, Analysis and Retrieval system of the SEC;

      (3)     seek or obtain, as the undersigned's representative
and on the undersigned's behalf, information regarding
transactions in the Company's securities from any third party,
including brokers, employee benefit plan administrators and
trustees, and the undersigned hereby authorizes any such third
party to release any such information to the herein appointed
attorney-in-fact and approves and ratifies any such release of
information; and

      (4)     take any other action of any type whatsoever in
connection with the foregoing which, in the opinion of such
attorney-in-fact, may be of benefit to, in the best interest of,
or legally required by, the undersigned, it being understood that
the documents executed by such attorney-in-fact on behalf of the
undersigned pursuant to this Power of Attorney shall be in such
form and shall contain such terms and conditions as such
attorney-in-fact may approve in such attorney-in-fact's

     The undersigned hereby grants to each such attorney-in-fact
full power and authority to do and perform any and every act and
thing whatsoever requisite, necessary, or proper to be done in
the exercise of any of the rights and powers herein granted, as
fully to all intents and purposes as the undersigned might or
could do if personally present, with full power of substitution
or revocation, hereby ratifying and confirming all that such
attorney-in-fact, or such attorney-in-fact's substitute or
substitutes, shall lawfully do or cause to be done by virtue of
this power of attorney and the rights and powers herein granted.
The undersigned acknowledges that the foregoing
attorneys-in-fact, in serving in such capacity at the request of
the undersigned, are not assuming nor relieving, nor is the
Company assuming nor relieving, any of the undersigned's
responsibilities to comply with Section 16 of the Exchange Act.
The undersigned acknowledges that neither the Company nor the
foregoing attorneys-in-fact assume (i) any liability for the
undersigned's responsibility to comply with the requirement of
the Exchange Act, (ii) any liability of the undersigned for any
failure to comply with such requirements, or (iii) any obligation
or liability of the undersigned for profit disgorgement under
Section 16(b) of the Exchange Act.

     This Power of Attorney shall remain in full force and effect
until the undersigned is no longer required to file Forms 3, 4,
and 5 with the SEC with respect to the undersigned's holdings of
and transactions in securities issued by the Company, unless
earlier revoked by the undersigned in a signed writing delivered
to the foregoing attorneys-in-fact.

     IN WITNESS WHEREOF, the undersigned has caused this Power of
Attorney to be executed as of the date set forth below.

/s/ James C. Mullen

Print Name:  James C. Mullen

Date: March 4, 2021