X0202 SCHEDULE 13G/A 0000918923 XXXXXXXX LIVE 1 Common Stock, $0.0001 par value per share 03/31/2026 0001822462 Foghorn Therapeutics Inc. 344174107 500 TECHNOLOGY SQUARE SUITE 700 CAMBRIDGE MA 02139 Rule 13d-1(c) BIOTECHNOLOGY VALUE FUND L P a DE 0.00 3164410.00 0.00 3164410.00 3164410.00 N 5.4 PN BVF I GP LLC a DE 0.00 3164410.00 0.00 3164410.00 3164410.00 N 5.4 OO BIOTECHNOLOGY VALUE FUND II LP a DE 0.00 2218382.00 0.00 2218382.00 2218382.00 N 3.8 PN BVF II GP LLC a DE 0.00 2218382.00 0.00 2218382.00 2218382.00 N 3.8 OO Biotechnology Value Trading Fund OS LP a E9 0.00 402467.00 0.00 402467.00 402467.00 N 0.7 PN BVF Partners OS Ltd. a E9 0.00 402467.00 0.00 402467.00 402467.00 N 0.7 CO BVF GP HOLDINGS LLC a DE 0.00 5382792.00 0.00 5382792.00 5382792.00 N 9.2 OO BVF PARTNERS L P/IL a DE 0.00 5866613.00 0.00 5866613.00 5866613.00 N 9.99 IA PN BVF INC/IL a DE 0.00 5866613.00 0.00 5866613.00 5866613.00 N 9.99 CO LAMPERT MARK N a X1 0.00 5866613.00 0.00 5866613.00 5866613.00 N 9.99 IN Foghorn Therapeutics Inc. Biotechnology Value Fund, L.P. ("BVF") BVF I GP LLC ("BVF GP") Biotechnology Value Fund II, L.P. ("BVF2") BVF II GP LLC ("BVF2 GP") Biotechnology Value Trading Fund OS LP ("Trading Fund OS") BVF Partners OS Ltd. ("Partners OS") BVF GP Holdings LLC ("BVF GPH") BVF Partners L.P. ("Partners") BVF Inc. Mark N. Lampert ("Mr. Lampert") Each of the foregoing is referred to as a "Reporting Person" and collectively as the "Reporting Persons." Biotechnology Value Fund, L.P. 44 Montgomery St., 40th Floor San Francisco, California 94104 BVF I GP LLC 44 Montgomery St., 40th Floor San Francisco, California 94104 Biotechnology Value Fund II, L.P. 44 Montgomery St., 40th Floor San Francisco, California 94104 BVF II GP LLC 44 Montgomery St., 40th Floor San Francisco, California 94104 Biotechnology Value Trading Fund OS LP PO Box 309 Ugland House Grand Cayman, KY1-1104 Cayman Islands BVF Partners OS Ltd. PO Box 309 Ugland House Grand Cayman, KY1-1104 Cayman Islands BVF GP Holdings LLC 44 Montgomery St., 40th Floor San Francisco, California 94104 BVF Partners L.P. 44 Montgomery St., 40th Floor San Francisco, California 94104 BVF Inc. 44 Montgomery St., 40th Floor San Francisco, California 94104 Mark N. Lampert 44 Montgomery St., 40th Floor San Francisco, California 94104 Biotechnology Value Fund, L.P. Delaware BVF I GP LLC Delaware Biotechnology Value Fund II, L.P. Delaware BVF II GP LLC Delaware Biotechnology Value Trading Fund OS LP Cayman Islands BVF Partners OS Ltd. Cayman Islands BVF GP Holdings LLC Delaware BVF Partners L.P. Delaware BVF Inc. Delaware Mark N. Lampert United States Y As of the close of business on March 31, 2026, the Reporting Persons and a certain Partners managed account (the "Partners Managed Account") held pre-funded warrants (the "Pre-Funded Warrants") exercisable for an aggregate of 6,050,782 Shares, subject to the Pre-Funded Warrants Blocker (as defined and described below). The Pre-Funded Warrants are exercisable immediately, do not expire, and have an exercise price of $0.0001 per Share. A holder of Pre-Funded Warrants shall not have the right to exercise any portion of the Pre-Funded Warrants pursuant to the terms and conditions thereof and any such exercise shall be null and void and treated as if never made to the extent that immediately prior to or after giving effect to such exercise, such holder together with the other Attribution Parties (as defined in the Form of Pre-Funded Warrant to Purchase Common Stock) collectively would beneficially own in excess of 9.99% of the number of Shares outstanding immediately after giving effect to such exercise (the "Pre-Funded Warrants Blocker"). As of the close of business on March 31, 2026, the Pre-Funded Warrants Blocker limits the exercise of the Pre-Funded Warrants by the Reporting Persons and the Partners Managed Account to 24,613 Shares out of 6,050,782 Shares underlying the Pre-Funded Warrants owned by them in the aggregate. As of the close of business on March 31, 2026, the Reporting Persons and the Partners Managed Account held Series 1 Warrants (the "Series 1 Warrants") exercisable for an aggregate of 1,862,891 Shares, and Series 2 Warrants (the "Series 2 Warrants", and together with the Series 1 Warrants, the "Series Warrants") exercisable for an aggregate of 1,862,891 Shares, subject to the Series Warrants Blocker (as defined and described below). The Series 1 Warrants are exercisable immediately, expire on June 30, 2027, and have an exercise price of $13.42 per Share. The Series 2 Warrants are exercisable immediately, expire on December 31, 2030, and have an exercise price of $20.13 per Share. Each holder of Series Warrants will be prohibited from exercising such Series Warrant if, as a result of such exercise, the holder, together with its affiliates, would own more than 9.99% of the total number of Shares then issued and outstanding (the "Series Warrants Blocker"), subject to certain limited adjustments. As of the close of business on March 31, 2026, the Series Warrants Blocker prohibits the exercise of all of the Series Warrants held by the Reporting Persons and in the Partners Managed Account. As of the close of business on March 31, 2026, (i) BVF beneficially owned 3,164,410 Shares, including 24,613 Shares underlying certain Pre-Funded Warrants held by it and excluding (a) 3,187,985 Shares underlying certain Pre-Funded Warrants held by it, (b) 1,022,635 Shares underlying the Series 1 Warrants held by it, and (c) 1,022,635 Shares underlying the Series 2 Warrants held by it; (ii) BVF2 beneficially owned 2,218,382 Shares, excluding (a) 2,427,960 Shares underlying the Pre-Funded Warrants held by it, (b) 703,630 Shares underlying the Series 1 Warrants held by it, and (c) 703,630 Shares underlying the Series 2 Warrants held by it; and (iii) Trading Fund OS beneficially owned 402,467 Shares, excluding (a) 313,925 Shares underlying the Pre-Funded Warrants held by it, (b) 109,394 Shares underlying the Series 1 Warrants held by it, and (c) 109,394 Shares underlying the Series 2 Warrants held by it. BVF GP, as the general partner of BVF, may be deemed to beneficially own the 3,164,410 Shares beneficially owned by BVF. BVF2 GP, as the general partner of BVF2, may be deemed to beneficially own the 2,218,382 Shares beneficially owned by BVF2. Partners OS, as the general partner of Trading Fund OS, may be deemed to beneficially own the 402,467 Shares beneficially owned by Trading Fund OS. BVF GPH, as the sole member of each of BVF GP and BVF2 GP, may be deemed to beneficially own the 5,382,792 Shares beneficially owned in the aggregate by BVF and BVF2. Partners, as the investment manager of BVF, BVF2 and Trading Fund OS, and the sole member of Partners OS, may be deemed to beneficially own the 5,866,613 Shares beneficially owned in the aggregate by BVF, BVF2 and Trading Fund OS and held in the Partners Managed Account, including 81,354 Shares held in the Partners Managed Account, which excludes (a) 96,299 Shares underlying the Pre-Funded Warrants, (b) 27,232 Shares underlying certain Series 1 Warrants, and (c) 27,232 Shares underlying certain Series 2 Warrants held in the Partners Managed Account. BVF Inc., as the general partner of Partners, may be deemed to beneficially own the 5,866,613 Shares beneficially owned by Partners. Mr. Lampert, as a director and officer of BVF Inc., may be deemed to beneficially own the 5,866,613 Shares beneficially owned by BVF Inc. The foregoing should not be construed in and of itself as an admission by any Reporting Person as to beneficial ownership of any Shares owned by another Reporting Person. BVF GP disclaims beneficial ownership of the Shares beneficially owned by BVF. BVF2 GP disclaims beneficial ownership of the Shares beneficially owned by BVF2. Partners OS disclaims beneficial ownership of the Shares beneficially owned by Trading Fund OS. BVF GPH disclaims beneficial ownership of the Shares beneficially owned by BVF and BVF2. Each of Partners, BVF Inc. and Mr. Lampert disclaims beneficial ownership of the Shares beneficially owned by BVF, BVF2 and Trading Fund OS and held in the Partners Managed Account, and the filing of this statement shall not be construed as an admission that any such person or entity is the beneficial owner of any such securities. The following percentages are based upon a denominator that is the sum of (i) 58,700,246 Shares outstanding as of February 27, 2026, which is the total number of Shares outstanding as reported in the Issuer's Annual Report on Form 10-K filed with the Securities and Exchange Commission on March 11, 2026, and (ii) 24,613 Shares underlying the Pre-Funded Warrants held by the Reporting Persons that are currently exercisable, as applicable. As of the close of business on March 31, 2026, (i) BVF beneficially owned approximately 5.4% of the outstanding Shares, (ii) BVF2 beneficially owned approximately 3.8% of the outstanding Shares, (iii) Trading Fund OS beneficially owned less than 1% of the outstanding Shares, (iv) BVF GP may be deemed to beneficially own approximately 5.4% of the outstanding Shares, (v) BVF2 GP may be deemed to beneficially own approximately 3.8% of the outstanding Shares, (vi) Partners OS may be deemed to beneficially own less than 1% of the outstanding Shares, (vii) BVF GPH may be deemed to beneficially own approximately 9.2% of the outstanding Shares, and (viii) each of Partners, BVF Inc. and Mr. Lampert may be deemed to beneficially own approximately 9.99% of the outstanding Shares (less than 1% of the outstanding Shares are held in the Partners Managed Account). See Cover Pages Items 5-9. See Cover Pages Items 5-9. See Cover Pages Items 5-9. See Cover Pages Items 5-9. Y N BVF GP, BVF GPH, Partners, BVF Inc. and Mr. Lampert share voting and dispositive power over the Shares beneficially owned by BVF. BVF GPH, Partners, BVF Inc. and Mr. Lampert share voting and dispositive power over the Shares beneficially owned by BVF2. Partners, BVF Inc. and Mr. Lampert share voting and dispositive power over the Shares beneficially owned by Trading Fund OS and held in the Partners Managed Account. Y N See Exhibit 99.1 to the Schedule 13G filed by the Reporting Persons with the Securities and Exchange Commission on May 30, 2024. 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. BIOTECHNOLOGY VALUE FUND L P /s/ Mark N. Lampert 05/15/2026 BVF I GP LLC /s/ Mark N. Lampert 05/15/2026 BIOTECHNOLOGY VALUE FUND II LP /s/ Mark N. Lampert 05/15/2026 BVF II GP LLC /s/ Mark N. Lampert 05/15/2026 Biotechnology Value Trading Fund OS LP /s/ Mark N. Lampert 05/15/2026 BVF Partners OS Ltd. /s/ Mark N. Lampert 05/15/2026 BVF GP HOLDINGS LLC /s/ Mark N. Lampert 05/15/2026 BVF PARTNERS L P/IL /s/ Mark N. Lampert 05/15/2026 BVF INC/IL /s/ Mark N. Lampert 05/15/2026 LAMPERT MARK N /s/ Mark N. Lampert 05/15/2026