SGT-003

United States – October 29, 2026 -- Solid Biosciences has dosed 33 children aged 1 to 10 with its investigational gene therapy SGT-003 for Duchenne muscular dystrophy, and a Phase 3 trial has enrolled its first patient.

Safety data show no liver, kidney or heart-inflammation cases

The figures come from INSPIRE DUCHENNE, a Phase 1/2, open-label, multi-center study, with data cut off on January 9, 2026. SGT-003 has been generally well tolerated using prophylactic steroids alone for immune suppression. The company reports no cases of drug-induced liver injury, thrombotic microangiopathy, atypical hemolytic uremic syndrome or myocarditis.

Cardiac monitoring has shown consistent reductions in markers of cardiac injury, with early signals of normalization. The company also reports microdystrophin expression and improvements across multiple biomarkers of muscle health.

United States – October 28, 2026 -- Solid Biosciences has dosed 40 participants with its Duchenne gene therapy SGT-003 and reported positive interim safety and biomarker data from the ongoing Phase 1/2 INSPIRE DUCHENNE trial. The company presented the update at the 2026 MDA Clinical & Scientific Conference.

The therapy delivers a shortened dystrophin protein

SGT-003 delivers microdystrophin, a shortened version of dystrophin designed to help support and protect muscle cells during movement. The data show robust microdystrophin expression. They also show restoration of beta-sarcoglycan and nNOS, proteins that normally work with dystrophin in the dystrophin-associated protein complex (DAPC), the muscle cell support system.

United States – October 27, 2026 -- Solid Biosciences has expanded its INSPIRE DUCHENNE gene therapy trial to 43 participants and now accepts children aged 4 to under 12, up from the previous range of 4 to under 8.

Three participants dosed with no serious adverse events

INSPIRE DUCHENNE is a first-in-human, multicenter, Phase 1/2 open-label study. It tests the safety, tolerability and efficacy of a single intravenous infusion of SGT-003, a next-generation AAV gene therapy candidate, in ambulant boys with Duchenne.

Three participants have been dosed so far. According to Solid, SGT-003 has been well tolerated to date, and no serious adverse events have been reported. The company plans to share safety, expression and biomarker data from these first three patients, along with a trial update, in the first quarter of 2025.

Global – October 27, 2026 -- Fifty-three boys with Duchenne muscular dystrophy have now received the investigational gene therapy SGT-003, and a Phase 3 trial is already enrolling patients in Australia and Canada. Solid Biosciences shared the update in a letter to the Duchenne community as the annual Parent Project Muscular Dystrophy (PPMD) conference got under way.

The Phase 1/2 trial spans ages 0 to 10

The count comes from the Phase 1/2 INSPIRE DUCHENNE trial and reflects a June 22, 2026, enrollment cutoff. Participants range from 0 to 10 years old. One of them is a 6-month-old boy who, to the company's knowledge, is the youngest child ever dosed with a microdystrophin gene therapy.

Solid reports no cases of four serious safety conditions

The company describes SGT-003 as generally well tolerated. It reports no observed cases of drug-induced liver injury, myocarditis, thrombotic microangiopathy or atypical hemolytic uremic syndrome.

United States – October 27, 2026 -- Fifteen people with Duchenne muscular dystrophy had received the investigational gene therapy SGT-003 in the INSPIRE DUCHENNE clinical study as of August 12, 2025, according to developer Solid Biosciences.

Ten trial sites span four countries

The multi-center, open-label trial now runs 10 active clinical sites in the United States, Canada, Italy, and the United Kingdom. More sites are expected to open later this year.

Solid Biosciences expects to have treated at least 20 patients aged 0 to under 12 by the end of 2025. It anticipates widening enrollment to older patients in 2026.