X0206 3 2022-12-02 0 0001707502 Solid Biosciences Inc. SLDB 0001578965 Koppel Adam C/O BAIN CAPITAL LIFE SCIENCES INVESTORS LLC, 200 CLARENDON STREET BOSTON MA 02116 1 0 1 0 Common Stock 3130423 I See footnotes Represents shares of the Issuer's Common Stock held by BCLS SB Investco, LP ("BCLS SB"), Bain Capital Life Sciences Fund II, L.P. ("BCLS Fund II"), BCLS II Investco, LP ("BCLS II Investco") and BCIP Life Sciences Associates, LP ("BCIPLS" and, together with BCLS SB, BCLS Fund II and BCLS II Investco, the "Bain Capital Life Sciences Entities"). Dr. Koppel is a Managing Director of Bain Capital Life Sciences Investors, LLC ("BCLSI"). BCLSI (i) is the ultimate general partner of each of BCLS SB, BCLS Fund II and BCLS II Investco and (ii) governs the investment strategy and decision-making process with respect to investments held by BCIPLS. As a result, Dr. Koppel may be deemed to share voting and dispositive power with respect to the securities held by the Bain Capital Life Sciences Entities. Dr. Koppel disclaims beneficial ownership of such securities, except to the extent of his pecuniary interest therein. /s/ Adam Koppel 2022-12-05