Solid Biosciences Provides Interim Positive Clinical Update on Phase 1/2 INSPIRE DUCHENNE Trial

Core Insights - Solid Biosciences Inc. reported positive interim data from the Phase 1/2 INSPIRE DUCHENNE trial of SGT-003, indicating robust microdystrophin expression and improvements in muscle integrity and cardiac function [1][2][3] Group 1: Clinical Trial Data - 40 participants have been dosed with SGT-003 in the INSPIRE DUCHENNE trial, which is an open-label, single-dose, multicenter trial designed to evaluate the safety, tolerability, and efficacy of SGT-003 in pediatric participants with Duchenne [1][3] - Interim data showed robust mean vector copies per nucleus and microdystrophin expression, with Day 90 results indicating 60% microdystrophin expression by western blot and 63% microdystrophin-positive fibers by immunofluorescence [5][8] - Improvements in muscle integrity biomarkers were observed, including a 38% reduction in serum creatine kinase (CK) and a 44% reduction in embryonic myosin heavy chain (eMHC) positive fibers at Day 90 [11][10] Group 2: Safety and Tolerability - SGT-003 has been generally well tolerated among participants, with a promising safety profile observed in the trial [4][6] - The treatment regimen involves a low-burden, steroid-only prophylactic immunomodulation approach [4][6] Group 3: Regulatory and Future Plans - The company is pursuing guidance from the FDA on a potential accelerated approval pathway for SGT-003 and plans to have additional meetings in the first half of 2026 [2][15] - Solid Biosciences has reached alignment with the FDA on the study design for the Phase 3 IMPACT DUCHENNE trial, which is set to begin participant dosing in the first quarter of 2026 [14][15] Group 4: Mechanism of Action - SGT-003's microdystrophin construct includes the R16/R17 binding domain, which is crucial for localizing nNOS to muscle, potentially improving blood flow and reducing muscle breakdown [7][18] - The therapy aims to restore key components of the dystrophin-associated protein complex (DAPC), which is critical for muscle integrity [2][9]