Sec Form 4 Filing - Domain Partners VIII, L.P. @ Dicerna Pharmaceuticals Inc - 2017-12-18

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 Domain Partners VIII, L.P. 2. Issuer Name and Ticker or Trading Symbol Dicerna Pharmaceuticals Inc [ DRNA] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director X __ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) C/O DOMAIN ASSOCIATES, LLC, ONE PALMER SQUARE 3. Date of Earliest Transaction (MM/DD/YY) 12/18/2017 (Street) PRINCETON, NJ08542 4. If Amendment, Date Original Filed (MM/DD/YY) 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 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 12/18/2017 C 1,678,432 A $ 3.19 3,431,139 D ( 3 ) Common Stock 12/18/2017 A 37,890 A 3,469,029 D ( 3 )

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 Redeemable Convertible Preferred Stock $ 3.19 12/18/2017 C 49,632 ( 1 ) ( 1 ) Common Stock 1,678,432 ( 2 ) $ 0 0 D ( 3 )

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Domain Partners VIII, L.P. C/O DOMAIN ASSOCIATES, LLC ONE PALMER SQUARE PRINCETON, NJ08542 X BLAIR JAMES C C/O DOMAIN ASSOCIATES, LLC ONE PALMER SQUARE PRINCETON, NJ08542 X DOVEY BRIAN H C/O DOMAIN ASSOCIATES, LLC ONE PALMER SQUARE PRINCETON, NJ08542 X TREU JESSE I C/O DOMAIN ASSOCIATES, LLC ONE PALMER SQUARE PRINCETON, NJ08542 X VITULLO NICOLE C/O DOMAIN ASSOCIATES, LLC ONE PALMER SQUARE PRINCETON, NJ08542 X Halak Brian K C/O DOMAIN ASSOCIATES, LLC ONE PALMER SQUARE PRINCETON, NJ08542 X X Signatures /s/ Lisa A. Kraeutler, as Attorney-in-Fact for Domain Partners VIII, L.P., J. Blair, B. Dovey, J. Treu, N. Vitullo and B. Halak 12/20/2017 Signature of Reporting Person Date

Explanation of Responses:

( 1 )The Redeemable Convertible Preferred Stock was immediately convertible upon its purchase on 04/11/2017, subject to certain conditions. The Redeemable Convertible Preferred Stock had no expiration date. ( 2 )Each share of Redeemable Convertible Preferred Stock had a stated value of $100 (the "Stated Value") and accrued dividends daily at an initial rate of 12% per annum, which was reduced to 8% per annum on October 28, 2017 in accordance with the Certificate of Designations for the Redeemable Convertible Preferred Stock. The Stated Value, as adjusted to give effect to such dividends, was referred to as the "Accrued Value." Each share of Redeemable Convertible Preferred Stock was convertible, at the option of the holder or, upon the occurrence of certain events, at the option of the Issuer, and subject to certain conditions, into a number of shares of Common Stock determined by dividing the Accrued Value by the conversion price. ( 3 )The securities reported as directly beneficially owned by the designated Reporting Person may be deemed to be indirectly beneficially owned by each of the Reporting Owners listed below, each of whom is a managing member of One Palmer Square Associates VIII, LLC, the sole general partner of the designated Reporting Person. Pursuant to Instruction 4(b)(iv) of Form 4, each such individual has elected to report as indirectly beneficially owned the entire number of securities owned by the designated Reporting Person, however each of them disclaims beneficial ownership of any securities, and any proceeds thereof, that exceed his or her pecuniary interest therein and/or that are not actually distributed to him or her. ( 4 )The Reporting Person received an additional 37,890 shares of Common Stock from the Issuer, representing the additional dividend accruals on the Redeemable Convertible Preferred Stock that the Reporting Person would have been entitled to receive up to and including March 31, 2018.

Remarks: This Form 4 does not constitute an exit filing for Brian K. Halak, a Director of the Issuer.

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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