The research landscape for Duchenne muscular dystrophy (DMD) has been steadily increasing. Researchers are exploring more therapies, including gene therapies, that could transform the lives of those with this rare genetic disorder. One such therapy currently being explored is SGT-003, developed by Solid Biosciences Inc. In fact, Solid Biosciences shared in a mid-January 2024 press release that SGT-003 earned Orphan Drug designation from the U.S. FDA. This follows the Fast Track designation that SGT-003 also received in December 2023. 

Orphan Drug designation is granted to drugs or biologics designed to treat, prevent, or diagnose rare conditions affecting fewer than 200,000 people nationwide. The drug developer—in this case, Solid Biosciences—also earns benefits such as fee waivers, tax credits, and up to seven years of market exclusivity if/when the drug is approved. 

Parent Project Muscular Dystrophy explains that SGT-003 is:

an adeno-associated virus (AAV) mediated gene transfer that contains an engineered version of the dystrophin gene (microdystrophin) [using] a novel AAV capsid. The microdystrophin gene in SGT-003 has been designed to produce a functional form of dystrophin protein containing the nNos domain in skeletal and cardiac muscles.

Researchers believe that SGT-003 could confer benefits such as increased muscle resilience, strength, and function, as well as improved treatment durability. 

Moving forward, Solid Biosciences plans on launching a Phase 1/2 clinical study to evaluate SGT-003. Dosing should begin by the end of the first quarter of 2024. 

What You Should Know: Duchenne Muscular Dystrophy (DMD) 

One of nine forms of muscular dystrophy, Duchenne muscular dystrophy is caused by mutations in the dystrophin gene. Normally, dystrophin helps muscles to function properly; dystrophin also contributes to muscle repair. Without dystrophin, muscles weaken and waste. DMD predominantly affects males, occurring in 1 in every 3,500 male births. Females are often genetic carriers, but approximately 1 in every 50 million females are affected by Duchenne muscular dystrophy. Children with Duchenne are often diagnosed before five years old. They may show signs or symptoms such as:

• Frequent falling
• Leg, pelvis, and thigh muscle weakness that progresses to other areas of the body
• Difficulty walking, running, or climbing
• Gower’s maneuver → needing help rising from the floor or walking hands up the legs to stand
• Fatigue
• Learning disabilities
• A weak neck and/or difficulty lifting the head
• Not walking by 15 months
• Cardiomyopathy
• An unusual, waddling gait 
• Pseudohypertrophy (calves that look larger than normal) 
• Respiratory failure and/or heart disease as the disease progresses