Solid Biosciences is a clinical-stage gene therapy company focused on rare neuromuscular and cardiac diseases. Solid has no approved products and generates no commercial revenue, funding operations through equity and debt financing. Its pipeline uses AAV gene transfer — a modified viral capsid delivers a functional copy of a mutated gene into a patient's cells — with the goal of a single-administration treatment that provides durable benefit. Solid's lead program, SGT-003, targets Duchenne muscular dystrophy and uses the proprietary POLARIS-101 capsid to deliver a microdystrophin transgene. Solid argues SGT-003 is differentiated by its R16/R17 domain, which restores nNOS to muscle — a feature no competing microdystrophin candidate includes. SGT-003 has been dosed in 41 participants in a Phase 1/2 trial, and a Phase 3 trial is underway. Beyond Duchenne, Solid is advancing SGT-212 for Friedreich's ataxia (Phase 1b) and SGT-501 for CPVT, a rare inherited arrhythmia syndrome (Phase 1b anticipated Q2 2026), plus earlier-stage cardiac programs. If products are approved, Solid would sell through specialty channels at a high one-time price per patient, consistent with the rare disease gene therapy model. Solid also licenses its POLARIS-101 capsid to third parties, with over 50 agreements executed and up to $97.1M in potential future milestones. Manufacturing is fully outsourced to CMOs. R&D dominates the cost structure, with 89 of 121 employees in research and development.