X0206 3 2020-09-24 0 0001678660 Prelude Therapeutics Inc PRLD 0001055951 ORBIMED ADVISORS LLC 601 LEXINGTON AVENUE, 54TH FLOOR NEW YORK NY 10022 1 0 1 0 0001682115 OrbiMed Capital GP VI LLC 601 LEXINGTON AVENUE, 54TH FLOOR NEW YORK NY 10022 1 0 1 0 Common Stock 206912 I See footnote Series A Preferred Stock Common Stock 3294743 I See footnote Series A Preferred Stock Non-Voting Common Stock 2196494 I See footnote Series B Preferred Stock Common Stock 4418186 I See footnote Series B Preferred Stock Non-Voting Common Stock 2945458 I See footnote Series C Preferred Stock Common Stock 619850 I See footnote Series C Preferred Stock Non-Voting Common Stock 413234 I See footnote These securities are held of record by OrbiMed Private Investments VI, L.P. ("OPI VI"). OrbiMed Capital GP VI LLC ("GP VI") is the general partner of OPI VI and OrbiMed Advisors LLC ("Advisors") is the managing member of GP VI. The Reporting Person is a member of Advisors. By virtue of such relationships, GP VI and Advisors may be deemed to have voting power and investment power over the securities held by OPI VI and as a result, may be deemed to have beneficial ownership over such securities. Advisors exercises voting and investment power through a management committee comprised of Carl L. Gordon, Sven H. Borho, and Jonathan T. Silverstein, each of whom disclaims beneficial ownership of the shares held by OPI VI. Each share of the Issuer's Series A Preferred Stock, Series B Preferred Stock, and Series C Preferred Stock will automatically convert into one share of the Issuer's Common Stock immediately prior to the closing of the Issuer's initial public offering and has no expiration date. Each share of the Issuer's Series A Preferred Stock, Series B Preferred Stock, and Series C Preferred Stock will automatically convert into one share of the Issuer's Non-Voting Common Stock immediately prior to the closing of the Issuer's initial public offering and has no expiration date. Each share of the Issuer's Non-Voting Common Stock is convertible into one share of the Issuer's Common Stock at any time at the option of the holder without consideration subject to a 9.99% beneficial ownership limitation which may be increased or decreased by the holder upon 61 days' notice to the Issuer. OrbiMed Advisors LLC; By /s/Douglas Coon, Chief Compl Ofcr. OrbiMed Capital GP VI LLC; By /s/Douglas Coon, Chief Compl Ofcr. 2020-09-24