SGT-001 is an experimental gene therapy being developed by Solid Biosciences to treat Duchenne muscular dystrophy (DMD), a type of muscular dystrophy characterized by progressive muscle weakness and atrophy.
DMD is caused by mutations in the DMD gene, which provides genetic instructions for making a protein called dystrophin. Dystrophin is a structural protein that provides support to muscle cells when they stretch and contract. Without dystrophin, muscle contractions cause small tears in muscle tissue that cannot be repaired properly, and the muscles weaken. Dystrophin is a very large protein complex, which has limited the efficacy of gene therapies to date. This trial is currently under clinical hold.
How SGT-001 works
SGT-001 is a gene therapy that uses a virus, modified so it cannot cause disease, to transmit a piece of DNA into muscle cells. This DNA encodes for a small synthetic dystrophin (called a microdystrophin) that has the key components of normal dystrophin. Once the gene is within cells, it is hoped that it will be expressed normally and hopefully slow or reverse disease progression for all types of DMD-causing mutations.
SGT-001 in clinical trials
A Phase 1/2 clinical trial (NCT03368742, nicknamed IGNITE-DMD) aims to recruit 16 DMD patients ages 4 to 17 at the University of Florida and the University of Massachusetts Memorial Medical Center for a single ascending dose study to evaluate the safety, tolerability, and efficacy of SGT-001. Patients will be randomly assigned to an active treatment group or an untreated control group. Patients in the active treatment group will receive a single intravenous (into the bloodstream) infusion of SGT-001 and will be followed for approximately two years. Patients in the untreated control group who continue to meet treatment criteria will receive SGT-001 after one year on the study. The primary outcome measured will be levels of microdystrophin present in the muscles following treatment. Microdystrophin levels will be measured using muscle biopsies obtained from patients in the treatment group.
The preliminary results from the first six patients (three in the treatment group and three in the untreated control group) indicated that low levels of microdystrophin were present in the muscle of the treated patients, and no adverse events were reported. The next group enrolled will receive a higher dose of SGT-001 as part of the dose-escalation planned for the study.
Three patients have been given the higher dose in the second cohort of the trial so far. The first patient experienced a serious adverse event after dosing and the trial was put on clinical hold by the FDA in March of 2018. The patient was treated with steroids and has now resumed normal activity and the clinical hold was lifted in June of that year after Solid Biosciences address all of the FDA’s concerns. The trial has now been placed on a second clinical hold after the third patient receiving the higher dose experienced a serious adverse event. Solid Biosciences announced that they will work with the FDA to determine the next steps for the trial.
Last updated: Nov. 13, 2019
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