Solid Biosciences Inc. announced that it has received U.S. Food and Drug Administration (FDA) clearance of an Investigational New Drug (IND) application for SGT-003, the company?s next-generation Duchenne Muscular Dystrophy (Duchenne) gene therapy candidate. SGT-003 uses a proprietary, rationally designed capsid (AAV-SLB101) to deliver a DNA sequence encoding a shortened form of the dystrophin protein (microdystrophin), containing the R16 and R17 nNos binding protein domains. Preclinical data suggests this may be important for both muscular function and durability of benefit in patients.

Based on the clearance, Solid plans to move expeditiously to submit the study for IRB approval at the clinical trial sites and expects to commence patient screening shortly thereafter. The planned Phase 1/2 trial, SGT-003-101, is a first in human, open-label, multicenter trial to determine the safety and tolerability of SGT-003 in pediatric patients with DMD at a dose of 1E14vg/kg. SGT-003 will be administered as a one-time intravenous infusion to patients in two cohorts with a minimum of three patients each, with the potential for cohort expansion.

Cohort 1 will study patients aged 4 to < 6 years of age with DMD. Long-term safety and efficacy will be evaluated for a total of 5 years following treatment. In an mdx mouse model of Duchenne, SGT-003 demonstrated rapid transduction, showing robust microdystrophin expression levels in the heart, quadriceps, and diaphragm by day 4 post-gene therapy treatment.

SGT-003 in nonhuman primates was shown to increase biodistribution to cardiac and skeletal muscle including the diaphragm versus AAV9. These studies suggest increased transgene expression and an improved safety profile compared to first generation microdystrophin gene therapies.