X0306 4 2019-05-29 0 0001399529 Dicerna Pharmaceuticals Inc DRNA 0001703031 Bain Capital Life Sciences Investors, LLC 200 CLARENDON STREET BOSTON MA 02116 1 0 1 0 0001703030 Bain Capital Life Sciences Partners, LP 200 CLARENDON STREET BOSTON MA 02116 0 0 1 0 0001687968 Bain Capital Life Sciences Fund, L.P. 200 CLARENDON STREET BOSTON MA 02116 0 0 1 0 0001702921 BCIP Life Sciences Associates, LP 200 CLARENDON STREET BOSTON MA 02116 0 0 1 0 0001702957 Schwartz Jeffrey Lawrence 200 CLARENDON STREET BOSTON MA 02116 0 0 1 0 0001578965 Koppel Adam 200 CLARENDON STREET BOSTON MA 02116 1 0 1 0 Common Stock 2019-05-29 4 S 0 1600000 12.50 D 7330237 I See footnotes On May 29, 2019, Bain Capital Life Sciences Fund, L.P. ("BC LS") and BCIP Life Sciences Associates, LP ("BCIP LS" and, together with BC LS, the "Bain Life Sciences Entities") sold 1,447,289 and 152,711 shares of common stock, respectively, directly to a private investor. Dr. Koppel is a director of the Issuer. Bain Capital Life Sciences Partners, LP ("BC LS P") is the general partner of BC LS. As a result, BC LS P may be deemed to share voting and dispositive power with respect to the securities held by BC LS. BC LS P disclaims beneficial ownership of such securities except to the extent of its pecuniary interest therein. Bain Capital Life Sciences Investors, LLC ("BCI LS"), whose managers are Jeffrey Schwartz and Adam Koppel, is the general partner of BC LS P and governs the investment strategy and decision-making process with respect to investments held by BCIP LS, whose general partner is Boylston Coinvestors, LLC. As a result of the relationships described herein, each of BCI LS, Mr. Schwartz and Dr. Koppel may be deemed to share voting and dispositive power with respect to the securities held by the Bain Life Sciences Entities. BCI LS, Mr. Schwartz and Dr. Koppel each disclaim beneficial ownership of such securities except to the extent of their pecuniary interest therein. BAIN CAPITAL LIFE SCIENCES INVESTORS, LLC, By: /s/ Adam Koppel, Managing Director 2019-05-31 BAIN CAPITAL LIFE SCIENCES PARTNERS, LP, By: Bain Capital Life Sciences Investors, LLC, its general partner, By: /s/ Adam Koppel, Managing Director 2019-05-31 BAIN CAPITAL LIFE SCIENCES FUND, L.P., By: Bain Capital Life Sciences Partners, LP, its general partner, By: Bain Capital Life Sciences Investors, LLC, its general partner, By: /s/ Adam Koppel, Managing Director 2019-05-31 BCIP LIFE SCIENCES ASSOCIATES, LP, By: Boylston Coinvestors, LLC, its general partner, By: /s/ Adam Koppel, Authorized Signatory 2019-05-31 /s/ Jeffrey Schwartz 2019-05-31 /s/ Adam Koppel 2019-05-31