X0306 4 2020-06-30 0 0001805890 Fusion Pharmaceuticals Inc. FUSN 0001488771 Christenson Johan C/O FUSION PHARMACEUTICALS INC. 270 LONGWOOD ROAD SOUTH HAMILTON A6 L8P 0A6 ONTARIO, CANADA 1 0 0 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 are 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 Class A Preferred Exchangeable Shares have no expiration date. The securities are held directly 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. The reporting person has an indirect interest in HCSA and is an employee of HealthCap VII Advisor AB. The reporting person disclaims beneficial ownership of Shares and Preferred Stock held by HCLP except to the extent of any pecuniary interest therein. Represents Class B Preferred Exchangeable Shares of Fusion Pharmaceuticals (Ireland) Limited. The Class B Preferred Exchangeable Shares of Fusion Pharmaceuticals (Ireland) Limited are 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. The Class B Preferred Exchangeable Shares have no expiration date. /s/ John Crowley, Attorney-in-Fact 2020-07-02