Solid Biosciences Aligns with FDA on Phase 3 Design for SGT-003 Gene Therapy

CHARLESTOWN, MA – February 9, 2026 – Solid Biosciences Inc. (Nasdaq: SLDB) has reached a pivotal regulatory milestone following a positive Type C meeting with the FDA regarding SGT-003, its next-generation AAV gene therapy for Duchenne muscular dystrophy (DMD). The agency aligned on the design of the Phase 3 IMPACT DUCHENNE trial, a randomized, double-blind, placebo-controlled study targeting ambulant patients aged 7 to <12. The primary endpoint will evaluate the change in “Time to Rise” (TTR) velocity from a supine position over 18 months.

The company also shared significant clinical progress: 36 participants have been dosed in the ongoing Phase 1/2 INSPIRE DUCHENNE trial as of today, with SGT-003 remaining generally well-tolerated. Solid expects to dose the first participant in the Phase 3 trial in Q1 2026. Looking ahead, the company is preparing for a second FDA meeting in the first half of 2026 to discuss a potential accelerated approval pathway, leveraging the confirmatory evidence provided by the IMPACT DUCHENNE study.

SGT-003 utilizes the proprietary AAV-SLB101 capsid, designed for enhanced muscle transduction and reduced liver targeting, and features a unique microdystrophin construct intended to improve muscle blood flow and reduce fatigue.