X0306 4 2022-04-27 1 0001290149 Sierra Oncology, Inc. SRRA 0001713663 Longitude Capital Partners III, LLC 2740 SAND HILL ROAD SECOND FLOOR MENLO PARK CA 94025 0 0 1 0 0001674099 Longitude Venture Partners III, L.P. 2740 SAND HILL ROAD SECOND FLOOR MENLO PARK CA 94025 0 0 1 0 0001431159 Tammenoms Bakker Juliet 2740 SAND HILL ROAD SECOND FLOOR MENLO PARK CA 94025 0 0 1 0 0001253886 ENRIGHT PATRICK G 2740 SAND HILL ROAD SECOND FLOOR MENLO PARK CA 94025 0 0 1 0 0001865779 Longitude Prime Partners, LLC 2740 SAND HILL ROAD, SECOND FLOOR MENLO PARK CA 94025 0 0 1 0 0001865844 Longitude Prime Fund, L.P. 2740 SAND HILL ROAD, SECOND FLOOR MENLO PARK CA 94025 0 0 1 0 Common Stock 2022-04-27 4 J 0 175000 0.00 D 0 I See footnote Common Stock 2022-04-27 4 J 0 1964771 0.00 D 0 I See footnote Common Stock 2022-04-27 4 J 0 5023 0.00 A 5023 I See footnote Common Stock 2022-04-27 4 J 0 2152 0.00 A 2152 I See footnote Common Stock 2022-04-27 4 J 0 7175 0.00 A 7175 I See footnote Common Stock 2022-04-27 4 J 0 588 0.00 A 5611 I See footnote Common Stock 2022-04-27 4 J 0 252 0.00 A 2404 I See footnote Common Stock 2022-04-27 4 J 0 840 0.00 A 8015 I See footnote Represents a pro rata distribution, and not a purchase or sale, without additional consideration by Longitude Prime Fund, L.P. ("LPF") to its general and limited partners. The securities are held directly by LPF. Longitude Prime Partners, LLC ("LPP"), the general partner of LPF, may be deemed to have voting and investment power with respect to the shares held by LPF. Patrick G. Enright and Juliet Tammenoms Bakker are the managing members of LPP and may be deemed to share voting, investment and dispositive power over such securities. Each of LPP, Mr. Enright and Ms. Tammenoms Bakker disclaim beneficial ownership of such shares except to the extent of their respective pecuniary interests therein, and the inclusion of such securities in this report shall not be deemed an admission of beneficial ownership of the reported securities for purposes of Section 16 or for any other purpose. Represents a pro rata distribution, and not a purchase or sale, without additional consideration by Longitude Venture Partners III, L.P. ("LVP III") to its general and limited partners. These securities are held directly by LVP III. Longitude Capital Partners III, LLC ("LCP III") is the general partner of LVP III and may be deemed to have voting, investment and dispositive power with respect to such securities. Patrick G. Enright and Juliet Tammenoms Bakker are the managing members of LCP III and may be deemed to share voting, investment and dispositive power over such securities. Each of LCP III, Mr. Enright, and Ms. Tammenoms Bakker disclaim beneficial ownership over such securities except to the extent of their respective pecuniary interest therein, and the inclusion of such securities in this report shall not be deemed an admission of beneficial ownership of the reported securities for purposes of Section 16 or for any other purpose. Represents a pro rata distribution, and not a purchase or sale, without additional consideration by LCP III to its members. These shares are held directly by Juliet Tammenoms Bakker. These shares are held by a trust. Juliet Tammenoms Bakker is the Investment Trustee of such trust and may be deemed to share voting and dispositive power with regard to the reported shares. Ms. Tammenoms Bakker disclaims beneficial ownership of such shares except to the extent of her pecuniary interest therein. These shares are held directly by Patrick G. Enright. Represents a pro rata distribution, and not a purchase or sale, without additional consideration by LPP to its members Longitude Venture Partners III, L.P.; By /s/ Patrick G. Enright, Managing Member of the general partner 2022-04-29 Longitude Capital Partners III, LLC; By /s/ Patrick G. Enright, Managing Member 2022-04-29 /s/ Juliet Tammenoms Bakker 2022-04-29 /s/ Patrick G. Enright 2022-04-29 Longitude Prime Partners, LLC, By: /s/ Patrick Enright, Managing Member 2022-04-29 Longitude Prime Fund, L.P., By: /s/ Patrick Enright, Managing Member of the general partner 2022-04-29