X0206 3 2015-07-15 0 0001290149 ProNAi Therapeutics Inc DNAI 0001357522 Thompson Peter A. C/O PRONAI THERAPEUTICS, INC. 2150 ? 885 WEST GEORGIA ST. VANCOUVER A1 V6C 3E8 BRITISH COLUMBIA, CANADA 1 0 0 0 Series D Preferred Stock Common Stock 1725790 I See Footnotes Each share of the issuer's Series D Preferred Stock will automatically convert into 1 share of the issuer's Common Stock immediately upon the closing of the issuer's initial public offering and has no expiration date. These securities are held of record by OrbiMed Private Investments V, LP ("OPI V"). OrbiMed Capital GP V LLC ("GP V") is the sole general partner of OPI V, and OrbiMed Advisors LLC ("Advisors") is the managing member of GP V. Samuel D. Isaly ("Isaly"), a natural person, is the managing member of and owner of a controlling interest in Advisors. By virtue of such relationships, GP V, Advisors and Isaly may be deemed to have voting and investment power over the securities held by OPI V and as a result may be deemed to have beneficial ownership over such securities. The Reporting Person is an employee of Advisors. Each of GP V, Advisors, Isaly and the Reporting Person disclaims beneficial ownership of the securities reported herein for purposes of Rule 16a-1(a) under the Securities Exchange Act of 1934, as amended (the "Exchange Act"), except to the extent of its or his pecuniary interest therein, if any. This report on Form 3 shall not be deemed an admission that any such entity or person, including the Reporting Person, is a beneficial owner of such securities for the purpose of Section 16 of the Exchange Act, or for any other purpose. /s/ Sukhi Jagpal as attorney-in-fact for Peter Thompson, M.D. 2015-07-15