X0306 4 2020-06-30 1 0001805890 Fusion Pharmaceuticals Inc. FUSN 0001645161 HealthCap VII, L.P. C/O HEALTHCAP VII GP S.A., 18 AVENUE OF D'OUCHY LAUSANNE V8 CH-1006 SWITZERLAND 0 0 1 0 0001790047 HealthCap VII GP S.A. C/O HEALTHCAP VII GP S.A., 18 AVENUE OF D'OUCHY LAUSANNE V8 CH-1006 SWITZERLAND 0 0 1 0 Common Shares 2020-06-30 4 C 0 2497345 A 2497345 I See Footnote Common Shares 2020-06-30 4 C 0 1069902 A 3567247 I See Footnote Common Shares 2020-06-30 4 P 0 240000 17.00 A 3807247 I See Footnote Class A Preferred Exchangeable Shares 2020-06-30 4 C 0 13333333 D Common Shares 2497345 0 I See Footnote Class B Preferred Exchangeable Shares 2020-06-30 4 C 0 5712216 D Common Shares 1069902 0 I See Footnote Represents Class A Preferred Exchangeable Shares of Fusion Pharmaceuticals (Ireland) Limited. The Class A Preferred Exchangeable Shares of Fusion Pharmaceuticals (Ireland) Limited were redeemable into Class A Preferred Shares of the Issuer. Upon the closing of the Issuer's initial public offering, the Class A Preferred Exchangeable Shares of Fusion Pharmaceuticals (Ireland) Limited were redeemed into Class A Preferred Shares of the Issuer on a one-for-one basis, which subsequently converted into Common Shares of the Issuer on a one-for-5.339 basis. The securities are directly held by HealthCap VII, L.P. ("HCLP"). HealthCap VII GP SA ("HCSA") is the sole general partner of HCLP and has voting and investment control over the Shares and Preferred Stock held by HCLP. Johan Christenson has an indirect interest in HCSA and is an employee of HealthCap VII Advisor AB. Each of the General Partner and Dr. Christenson disclaims, for purposes of Section 16 of the Securities Exchange Act of 1934, beneficial ownership of such securities, except to the extent of his/its indirect pecuniary interest therein, and this report shall not be deemed an admission that the General Partner or Dr. Christenson is the beneficial owner of such securities for purposes of Section 16 or for any other purposes. Represents Class B Preferred Exchangeable Shares of Fusion Pharmaceuticals (Ireland) Limited. The Class B Preferred Exchangeable Shares of Fusion Pharmaceuticals (Ireland) Limited were redeemable into Class B Preferred Shares of the Issuer. Upon the closing of the Issuer's initial public offering, the Class B Preferred Exchangeable Shares of Fusion Pharmaceuticals (Ireland) Limited were redeemed into Class B Preferred Shares of the Issuer on a one-for-one basis, which subsequently converted into Common Shares of the Issuer on a one-for-5.339 basis. /s/ HealthCap VII L.P., By: By: HealthCap VII GP S.A., its general partner, By: /s/ Dag Richter, Name: Dag Richter, Title: Director, and By: /s/ Fabrice Bernhard, Name: Fabrice Bernhard, Title: General Manager 2020-07-02 /s/ HealthCap VII GP S.A., By: /s/ Dag Richter, Name: Dag Richter, Title: Director, and By: /s/ Fabrice Bernhard, Name: Fabrice Bernhard, Title: General Manager 2020-07-02