X0306 4 2021-08-31 0 0001789972 Cullinan Oncology, Inc. CGEM 0001691428 UBS Oncology Impact Fund L.P. C/O MPM ASSET MANAGEMENT LLC 450 KENDALL STREET CAMBRIDGE MA 02142 0 0 1 0 0001721036 Oncology Impact Fund (Cayman) Management L.P. C/O MPM ASSET MANAGEMENT LLC 450 KENDALL STREET CAMBRIDGE MA 02142 0 0 1 0 0001687078 BioImpact Capital LLC C/O MPM ASSET MANAGEMENT LLC 450 KENDALL STREET CAMBRIDGE MA 02142 0 0 1 0 Common Stock 2021-08-31 4 S 0 1285 29.43 D 7759840 D Common Stock 2021-08-31 4 S 0 1553 30.14 D 7758287 D Common Stock 2021-09-01 4 S 0 5714 29.47 D 7752573 D Common Stock 2021-09-02 4 S 0 15757 29.46 D 7736816 D Transaction effected pursuant to a plan established pursuant to Rule 10b5-1 on June 23, 2021. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $29.00 to $29.83 inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote. These securities are owned directly by UBS Oncology Impact Fund LP ("OIF"). The general partner of OIF is Oncology Impact Fund (Cayman) Management L.P. ("OIF GP"). The general partner of OIF GP is BioImpact Capital LLC. Dr. Ansbert Gadicke is a member of the Issuer's board of directors and is a managing partner of BioImpact Capital LLC. Each of the Reporting Persons disclaims beneficial ownership of the securities except to the extent of its pecuniary interest therein. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $30.01 to $30.19 inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $29.00 to $29.77 inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $29.00 to $29.88 inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote. /s/ Ansbert Gadicke, managing partner of BioImpact Capital LLC, the general partner of Oncology Impact Fund (Cayman) Management L.P., the general partner of UBS Oncology Impact Fund L.P 2021-09-02 /s/ Ansbert Gadicke, managing partner of BioImpact Capital LLC, the general partner of Oncology Impact Fund (Cayman) Management L.P. 2021-09-02 /s/ Ansbert Gadicke, managing partner of BioImpact Capital LLC 2021-09-02