Planning to initiate Phase 1/2 trial in pediatric DMD Patients –

– First cohort to study patients 4 to < 6 years of age –

“We are pleased to have the FDA’s clearance to proceed into the clinic with SGT-003, a new, innovative gene therapy candidate for Duchenne,” said Bo Cumbo, President and CEO at Solid Biosciences. “SGT-003 combines our differentiated microdystrophin transgene with a next generation muscle-tropic capsid and a transient transfection manufacturing process that may help address the unmet needs for the Duchenne community.” Jessie Hanrahan Ph.D. Chief Regulatory Officer added “We appreciate the FDA’s review of the IND and look forward to continuing to work in collaboration with the agency when we initiate dosing of DMD patients.”

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.

“IND clearance for SGT-003 is a critical step in bringing a potential next generation gene therapy to the clinic and making a meaningful impact on the lives of those living with Duchenne. We are working closely with clinical sites to dose the first participants, driven by the belief that better therapies are urgently required to treat this devastating disease,” said Gabriel Brooks, M.D., Chief Medical Officer at Solid Biosciences.

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.