X0306 4 2020-06-30 1 0001805890 Fusion Pharmaceuticals Inc. FUSN 0001193586 ADAMS STREET PARTNERS LLC ONE NORTH WACKER DRIVE SUITE 2700 CHICAGO IL 60606 0 0 1 0 Common Shares 2020-06-30 4 C 0 401423 A 401423 I See footnotes Common Shares 2020-06-30 4 C 0 308137 A 308137 I See footnotes Common Shares 2020-06-30 4 C 0 298898 A 298898 I See footnotes Common Shares 2020-06-30 4 C 0 447428 A 447428 I See footnotes Common Shares 2020-06-30 4 C 0 1041456 A 1041456 I See footnotes Common Shares 2020-06-30 4 C 0 161556 A 562979 I See footnotes Common Shares 2020-06-30 4 C 0 124013 A 432150 I See footnotes Common Shares 2020-06-30 4 C 0 120294 A 419192 I See footnotes Common Shares 2020-06-30 4 C 0 180072 A 627500 I See footnotes Common Shares 2020-06-30 4 C 0 419148 A 1460604 I See footnotes Class A Preferred Shares 2020-06-30 4 C 0 2143200 D Common Shares 401423 0 I See footnotes Class A Preferred Shares 2020-06-30 4 C 0 1645147 D Common Shares 308137 0 I See footnotes Class A Preferred Shares 2020-06-30 4 C 0 1595823 D Common Shares 298898 0 I See footnotes Class A Preferred Shares 2020-06-30 4 C 0 2388822 D Common Shares 447428 0 I See footnotes Class A Preferred Shares 2020-06-30 4 C 0 5560341 D Common Shares 1041456 0 I See footnotes Class B Preferred Shares 2020-06-30 4 C 0 862558 D Common Shares 161556 0 I See footnotes Class B Preferred Shares 2020-06-30 4 C 0 662111 D Common Shares 124013 0 I See footnotes Class B Preferred Shares 2020-06-30 4 C 0 642260 D Common Shares 120294 0 I See footnotes Class B Preferred Shares 2020-06-30 4 C 0 961412 D Common Shares 180072 0 I See footnotes Class B Preferred Shares 2020-06-30 4 C 0 2237832 D Common Shares 419148 0 I See footnotes The Class A Preferred Shares were convertible into Common Shares on a one-for-5.339 basis. Upon the closing of the Issuer's initial public offering, all Class A Preferred Shares converted into Common Shares. The shares are held directly by Adams Street 2014 Direct Fund LP ("AS 2014"). The shares are held directly by Adams Street 2015 Direct Venture/Growth Fund LP ("AS 2015"). The shares are held directly by Adams Street 2016 Direct Venture/Growth Fund LP ("AS 2016"). The shares are held directly by Adams Street 2017 Direct Venture/Growth Fund LP ("AS 2017"). The shares are held directly by Adams Street Venture/Growth Fund VI LP ("ASVG VI"). The Class B Preferred Shares were convertible into Common Shares on a one-for-5.339 basis. Upon the closing of the Issuer's initial public offering, all Class B Preferred Shares converted into Common Shares. Adams Street Partners, LLC as the managing member of the general partner of the general partner of AS 2014, AS 2015, AS 2016, AS 2017 and ASVG VI (collectively the "Funds"), may be deemed to beneficially own the shares held by the Funds. Thomas S. Bremner, Jeffrey T. Diehl, Elisha P. Gould, Robin Murray and Fred Wang, each of whom is a partner of Adams Street Partners, LLC (or a subsidiary thereof), may be deemed to have shared voting and investment power over the shares held by the Funds. Adams Street Partners, LLC and Thomas S. Bremner, Jeffrey T. Diehl, Elisha P. Gould, Robin Murray and Fred Wang disclaim beneficial ownership of the shares held by the Funds except to the extent of their pecuniary interest therein. ADAMS STREET PARTNERS, LLC By: /s/ Sara Robinson Dasse 2020-07-02