Kymera Therapeutics, Inc.

1. This transaction was made pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on December 11, 2025.

2. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $90.05 to $90.441 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 each separate price within the range set forth in this footnote.

3. These shares are held directly by Atlas Venture Fund X, L.P. ("Atlas Venture Fund X"). The general partner of Atlas Venture Fund X is Atlas Venture Associates X, L.P. ("AVA X LP"). Atlas Venture Associates X, LLC ("AVA X LLC") is the general partner of AVA X LP. The Reporting Person is a member of AVA X LLC and disclaims Section 16 beneficial ownership of the securities held by Atlas Venture Fund X, except to the extend of his pecuniary interest therein, if any.

4. The shares are owned directly by Atlas Venture Opportunity Fund I, L.P. ("AVOF"). Atlas Venture Associates Opportunity I, L.P. ("AVAO LP") is the general partner of AVOF. Atlas Venture Associates Opportunity I, LLC ("AVAO LLC") is the general partner of AVAO LP. The Reporting Person is a member of AVAO LLC and disclaims Section 16 beneficial ownership of such securities held by AVOF, except to the extent of his pecuniary interest therein, if any.