X0202 SCHEDULE 13G/A 0001352546 XXXXXXXX LIVE 2 Common Stock 03/31/2026 0001822462 Foghorn Therapeutics Inc. 344174107 99 Coolidge Ave, Suite 500 Watertown MA 02472 Rule 13d-1(c) Deerfield Mgmt, L.P. b DE 5139523.00 0.00 5139523.00 0.00 5139523.00 N 8.64 PN Comprised of (i) 4,394,367 shares of common stock and (ii) 745,156 shares of common stock issuable upon exercise of warrants, which, in each case, are held by Deerfield Partners, L.P., of which Deerfield Mgmt, L.P. is the general partner. The provisions of the warrants beneficially owned by the reporting person restrict the exercise of such securities to the extent that after such exercise the holder, its affiliates and other persons whose beneficial ownership of common stock would be aggregated for purposes of Section 13(d) of the Securities Exchange Act of 1934, as amended, would beneficially own in excess of 9.99% of the total number of shares of the Issuer then outstanding (the "Ownership Cap"). Accordingly, notwithstanding the number of shares reported, the reporting person disclaims beneficial ownership of the shares of common stock issuable upon exercise of such warrants to the extent that upon such exercise the number of shares beneficially owned by all reporting persons hereunder, in the aggregate, would exceed the Ownership Cap. Deerfield Management Company, L.P. b DE 5139523.00 0.00 5139523.00 0.00 5139523.00 N 8.64 PN Comprised of (i) 4,394,367 shares of common stock and (ii) 745,156 shares of common stock issuable upon exercise of warrants, which, in each case, are held by Deerfield Partners, L.P., of which Deerfield Management Company, L.P. is the investment advisor. The provisions of the warrants beneficially owned by the reporting person restrict the exercise of such securities to the extent that after such exercise the holder, its affiliates and other persons whose beneficial ownership of common stock would be aggregated for purposes of Section 13(d) of the Securities Exchange Act of 1934, as amended, would beneficially own in excess of 9.99% of the total number of shares of the Issuer then outstanding (the "Ownership Cap"). Accordingly, notwithstanding the number of shares reported, the reporting person disclaims beneficial ownership of the shares of common stock issuable upon exercise of such warrants to the extent that upon such exercise the number of shares beneficially owned by all reporting persons hereunder, in the aggregate, would exceed the Ownership Cap. Deerfield Partners, L.P. b DE 5139523.00 0.00 5139523.00 0.00 5139523.00 N 8.64 PN Comprised of (i) 4,394,367 shares of common stock and (ii) 745,156 shares of common stock issuable upon exercise of warrants. The provisions of the warrants beneficially owned by the reporting person restrict the exercise of such securities to the extent that after such exercise the holder, its affiliates and other persons whose beneficial ownership of common stock would be aggregated for purposes of Section 13(d) of the Securities Exchange Act of 1934, as amended, would beneficially own in excess of 9.99% of the total number of shares of the Issuer then outstanding (the "Ownership Cap"). Accordingly, notwithstanding the number of shares reported, the reporting person disclaims beneficial ownership of the shares of common stock issuable upon exercise of such warrants to the extent that upon such exercise the number of shares beneficially owned by all reporting persons hereunder, in the aggregate, would exceed the Ownership Cap. James E. Flynn b X1 5139523.00 0.00 5139523.00 0.00 5139523.00 N 8.64 IN Comprised of (i) 4,394,367 shares of common stock and (ii) 745,156 shares of common stock issuable upon exercise of warrants, which, in each case, are held by Deerfield Partners, L.P. The provisions of the warrants beneficially owned by the reporting person restrict the exercise of such securities to the extent that after such exercise the holder, its affiliates and other persons whose beneficial ownership of common stock would be aggregated for purposes of Section 13(d) of the Securities Exchange Act of 1934, as amended, would beneficially own in excess of 9.99% of the total number of shares of the Issuer then outstanding (the "Ownership Cap"). Accordingly, notwithstanding the number of shares reported, the reporting person disclaims beneficial ownership of the shares of common stock issuable upon exercise of such warrants to the extent that upon such exercise the number of shares beneficially owned by all reporting persons hereunder, in the aggregate, would exceed the Ownership Cap. Foghorn Therapeutics Inc. 99 Coolidge Ave, Suite 500, Watertown, MA 02472 James E. Flynn, Deerfield Mgmt, L.P., Deerfield Partners, L.P. and Deerfield Management Company, L.P. James E. Flynn, Deerfield Mgmt, L.P., Deerfield Partners, L.P. and Deerfield Management Company, L.P., 345 Park Avenue South, 12th Floor, New York, NY 10010 Deerfield Mgmt, L.P., Deerfield Management Company, L.P. and Deerfield Partners, L.P. - Delaware limited partnerships; James E. Flynn - United States citizen Y Deerfield Mgmt, L.P. - 5,139,523 shares Deerfield Management Company, L.P. - 5,139,523 shares Deerfield Partners, L.P. - 5,139,523 shares James E. Flynn - 5,139,523 shares Deerfield Mgmt, L.P. - 8.64% Deerfield Management Company, L.P. - 8.64% Deerfield Partners, L.P. - 8.64% James E. Flynn - 8.64% All Reporting Persons - 0 Deerfield Mgmt, L.P. - 5,139,523 Deerfield Management Company, L.P. - 5,139,523 Deerfield Partners, L.P. - 5,139,523 James E. Flynn - 5,139,523 All Reporting Persons - 0 Deerfield Mgmt, L.P. - 5,139,523 Deerfield Management Company, L.P. - 5,139,523 Deerfield Partners, L.P. - 5,139,523 James E. Flynn - 5,139,523 Y Y Y N See Exhibit B Y N By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under ?? 240.14a-11. Exhibit A. Joint Filing Agreement. Exhibit B. Item 8 Statement. Exhibit C. Power of Attorney (1). (1) Power of Attorney previously filed as Exhibit 24 to a Form 3 with regard to BiomX Inc. filed with the Securities and Exchange Commission on March 19, 2024 by Deerfield Private Design Fund V, L.P., Deerfield Healthcare Innovations Fund II, L.P., Deerfield Mgmt V, L.P., Deerfield Mgmt HIF II, L.P., Deerfield Management Company, L.P. and James E. Flynn. Deerfield Mgmt, L.P. /s/ Jonathan Isler 05/14/2026 Deerfield Management Company, L.P. /s/ Jonathan Isler 05/14/2026 Deerfield Partners, L.P. /s/ Jonathan Isler 05/14/2026 James E. Flynn /s/ Jonathan Isler 05/14/2026