X0306 4 2020-07-01 0 0001399529 Dicerna Pharmaceuticals Inc DRNA 0001598479 Brown Bob D C/O DICERNA PHARMACEUTICALS, INC. 33 HAYDEN AVENUE LEXINGTON MA 02421 0 1 0 0 See Remarks Common Stock 2020-07-01 4 M 0 8185 3.42 A 13185 D Common Stock 2020-07-01 4 S 0 5814 26.3604 D 7371 D Common Stock 2020-07-01 4 S 0 2371 26.8533 D 5000 D Employee Stock Option (Right to Buy) 3.42 2020-07-01 4 M 0 8185 0.00 D 2023-09-24 Common Stock 8185 40925 D The Reporting Person sold an aggregate of 8,185 shares of common stock on July 1, 2020 (the "Shares Sold") as reported in this Form 4. The Shares Sold represent 0.83% of 981,327 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 the date of this report. The sales reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on November 27, 2019. The price reported in Column 4 is a weighted-average price. These shares were sold in multiple transactions at prices ranging from $25.70 to $26.68, inclusive. The Reporting Person undertakes to provide to Dicerna Pharmaceuticals, Inc., any security holder of Dicerna Pharmaceuticals, Inc., or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in footnote (3) to this Form 4. The price reported in Column 4 is a weighted-average price. These shares were sold in multiple transactions at prices ranging from $26.73 to $26.97, inclusive. The Reporting Person undertakes to provide to Dicerna Pharmaceuticals, Inc., any security holder of Dicerna Pharmaceuticals, Inc., or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in footnote (4) to this Form 4. The vesting of these options was subject to achievement of pre-established performance goals. As of the transaction date, the options were fully vested. Chief Scientific Officer, EVP of R&D /s/ Douglas W. Pagan, attorney-in-fact 2020-07-06