RARE Daily

FDA Grants Solid RPDD for DMD Gene Therapy

April 1, 2024

Rare Daily Staff

The U.S. Food and Drug Administration granted Solid Biosciences Rare Pediatric Disease designation for SGT-003, the company’s experimental next-generation Duchenne muscular dystrophy gene therapy.

Duchenne muscular dystrophy (DMD) is a severe, progressive, degenerative muscle disease. DMD is caused by mutations in the Duchenne gene which encodes for dystrophin, a protein involved in muscle cell structure and signaling pathways. Without dystrophin, muscles throughout the body degenerate and become weak, eventually leading to loss of movement and independence, required support for breathing, cardiomyopathy, and premature death.

SGT-003 uses a proprietary capsid to deliver a DNA sequence encoding a shortened form of the dystrophin protein. Preclinical data suggests this may be important for both muscular function and durability of benefit in patients.

“Solid’s receipt of Rare Pediatric Disease Designation for SGT-003 highlights the continuing need for transformational treatments for this devastating disease,” said Bo Cumbo, president and CEO at Solid Biosciences. “The key components of SGT-003 were rationally designed to improve on first generation gene therapies to provide skeletal muscle tropism, enhanced durability, and improved clinical outcomes.

Rare Pediatric Disease Designation is granted by the FDA for serious or life-threatening diseases in which manifestations primarily affect children ages 18 years and younger. In addition, the disease must affect fewer than 200,000 people in the United States. The program is designed to encourage development of new drugs for the prevention and treatment of rare pediatric diseases. If a new biologics license application is approved for SGT-003, Solid may be eligible to receive a priority review voucher.

The vouchers are potentially lucrative because they are transferrable. The vouchers can be used to reduce the review time of an FDA application for an approval to six months from ten months. Several companies have sold these vouchers for around $100 million.

The company expects to activate clinical trial sites this month and will begin patient screening shortly after that. It anticipates dosing patients in the second quarter.

The planned phase 1/2 INSPIRE Duchenne trial is a first-in-human, open-label, multicenter trial to determine the safety and tolerability of SGT-003 in pediatric patients with DMD. 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 with DMD ages 4 to less than 6. Cohort 2 will study patients with DMD ages 6 to less than 8. Solid expects to share initial safety update for the first three to four patients enrolled in the INSPIRE Duchenne trial in mid-2024, and initial expression and functional data from those patients in the fourth quarter of 2024.

Photo: Bo Cumbo, president and CEO at Solid Biosciences

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