Rare Daily Staff

Solid Biosciences shares fell nearly 70 percent after the company reported disappointing preliminary data from its phase 1/2 study of SGT-001, its microdystrophin gene transfer for Duchenne muscular dystrophy, which showed low levels of microdystrophin protein expression in study patients.

The company said it is expediting planned dose escalation as soon as possible to see if that will amplify its effects.

Duchenne muscular dystrophy (DMD) is a rare genetic disorder caused by mutations in the dystrophin gene that result in the absence of dystrophin, a protein that keeps muscle cells intact. It leads to progressive muscle degeneration and weakness and occurs mainly in boys, most whom do not survive past their teen years.

Solid’s lead candidate, SGT-001, is a novel adeno-associated viral (AAV) vector-mediated gene transfer under investigation for its ability correct mutations in the dystrophin gene. SGT-001 is systemically administered to deliver a synthetic dystrophin transgene, called microdystrophin, to the body. This microdystrophin encodes for a functional protein surrogate that is expressed in muscles and stabilizes essential associated proteins. SGT-001 utilizes AAV9, which has an affinity for muscle and is currently being evaluated in multiple clinical programs in other indications.

“We believe that SGT-001 will be a meaningful treatment for patients with DMD and are confident we have the right approach in place to evaluate its potential at higher doses. We have already begun working to expedite the planned dose escalation strategy outlined in our clinical trial protocol,” said Ilan Ganot, co-founder, CEO, and president of Solid Biosciences. “This strategy is further supported by our scalable manufacturing process, from which we have sufficient drug product available to dose escalate without delay.”

Solid’s Ignite DMD study is designed to evaluate SGT-001 in ambulatory and non-ambulatory males with DMD aged 4 to 17 years, and assess its safety and tolerability, as well as efficacy as defined by microdystrophin expression. The study will also assess muscle function and mass, respiratory and cardiovascular function, serum and muscle biomarkers associated with microdystrophin production, patient reported outcomes and quality of life measures, among other endpoints.

Of the six patients enrolled in the Ignite DMD study, three were assigned to the active treatment group and three to the delayed treatment control group. The safety profile of SGT-001 at the low dose remained unchanged and all patients continue to be followed per the study protocol.

SGT-001 has been granted Rare Pediatric Disease Designation, and Fast Track Designation in the United States and Orphan Drug Designations in both the United States and European Union.

Photo: Ilan Ganot, Solid Bioscience

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