Sec Form 4 Filing - Weissman James B @ Dicerna Pharmaceuticals Inc - 2021-01-08

FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP 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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1. Name and Address of Reporting Person Weissman James B 2. Issuer Name and Ticker or Trading Symbol Dicerna Pharmaceuticals Inc [ DRNA] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director _____ 10% Owner X __ Officer (give title below) _____ Other (specify below) Chief Operating Officer & EVP (Last) (First) (Middle) C/O DICERNA PHARMACEUTICALS, INC., 75 HAYDEN AVENUE 3. Date of Earliest Transaction (MM/DD/YY) 01/08/2021 (Street) LEXINGTON, MA02421 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) __ X __ Form filed by One Reporting Person _____ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 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 01/08/2021 M 8,650 A 40,510 D Common Stock 01/08/2021 F 2,842 ( 2 ) D $ 23.29 37,668 D Common Stock 01/11/2021 S( 3 )( 4 ) 3,800 ( 3 ) D $ 23.99 33,868 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 (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 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 (MM/DD/YY) 7. Title and Amount of Underlying Securities (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 of Derivative Security: 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 Restricted Stock Units ( 1 ) 01/08/2021 M 8,650 ( 5 ) ( 5 ) Common Stock 8,650 $ 0 25,950 D Restricted Stock Units ( 1 ) 01/12/2021 A 15,100 ( 6 ) ( 6 ) Common Stock 15,100 $ 0 15,100 D Employee Stock Option (Right to Buy) $ 24.05 01/12/2021 A 68,100 ( 7 ) 01/11/2031 Common Stock 68,100 $ 0 68,100 D

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Weissman James B C/O DICERNA PHARMACEUTICALS, INC. 75 HAYDEN AVENUE LEXINGTON, MA02421 Chief Operating Officer & EVP Signatures /s/ Douglas W. Pagan, attorney-in-fact 01/12/2021 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Each restricted stock unit ("RSU") represents the contingent right to receive one share of the Issuer's Common Stock. ( 2 )Represents the number of shares of the Issuer's Common Stock withheld by the Issuer to cover tax withholding obligations in connection with the vesting of RSUs. ( 3 )The Reporting Person sold an aggregate of 3,800 shares of Common Stock on January 11, 2021 (the "Shares Sold") as reported in this Form 4. The Shares Sold represent 0.52% of 732,596 shares of Common Stock, which is the number of shares of Common Stock owned by the Reporting Person prior to the Shares Sold transaction reported in this Form 4, as well as shares issuable upon exercise or settlement of vested and unvested options and restricted stock units held by the Reporting Person as of January 11, 2021. ( 4 )The sales reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on December 8, 2020. ( 5 )The RSUs vest over a period of four years, with 25% of the RSUs vesting on each of the first, second, third and fourth anniversaries of January 8, 2020, subject in each case to the Reporting Person's continued employment or service with the Issuer through the applicable vesting date. ( 6 )The RSUs vest over a period of four years, with 25% of the RSUs vesting on each of the first, second, third and fourth anniversaries of December 15, 2020, subject in each case to the Reporting Person's continued employment or service with the Issuer through the applicable vesting date. ( 7 )The option vests in 48 substantially equal monthly installments, with the first installment vesting on the last day of January 2021, and the remaining shares vesting on the last day of each of the 47 months thereafter; subject in each case to the Reporting Person's continued employment or service with the Issuer through each applicable vesting 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).

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