Solid Biosciences AAV Gene Therapy for Friedreich’s Ataxia Garners Key FDA Pediatric Designation

December 01, 2025- Solid Biosciences Inc. (Nasdaq: SLDB) today announced that the U.S. Food and Drug Administration (FDA) has granted Rare Pediatric Disease designation to SGT-212, its investigational AAV vector-based gene therapy for Friedreich’s ataxia (FA). This is a significant regulatory step that recognizes the critical unmet need for new therapies for this life-threatening, degenerative disease.

Dual-Route AAV Delivery Targets FA’s Core Defect

SGT-212 is a recombinant AAV-based gene replacement therapy designed to deliver the full-length frataxin gene ($FXN$) via a dual route of administration, a unique strategy among FA programs currently in development.

The therapy employs two distinct infusions:

1. Direct Intradentate Nucleus (IDN) Infusion: This method uses an MRI-guided, stereotactic device to directly administer the AAV vector to the cerebellar dentate nuclei, a critical brain structure, to address the neurological manifestations of FA.

2. Intravenous (IV) Infusion: This systemic dose of the AAV vector is intended to increase therapeutic frataxin protein (FXN) levels in cardiomyocytes to target the cardiac and systemic clinical manifestations.

The FA is an inherited, multisystem disease caused by defects in the frataxin gene that disrupt the production of the essential mitochondrial protein, Frataxin. The lack of this protein causes progressive nervous system damage, movement problems (ataxia), and severe cardiac dysfunction, which is often the primary cause of death.

Jessie Hanrahan, Ph.D., Chief Regulatory & Preclinical Operations Officer of Solid Biosciences, stated, “Receiving Pediatric Rare Disease designation marks another significant milestone for our Friedreich’s ataxia program, SGT-212… Together with the Fast Track designation granted earlier this year, it recognizes our dual-route clinical approach for FALCON, our first-in-human trial, which is now screening participants, as an important first step in meeting an unmet need for FA.”

Expedited Review and Priority Review Voucher

The Rare Pediatric Disease designation is granted for serious or life-threatening diseases that primarily affect individuals under 18 years of age. This status makes SGT-212 potentially eligible to receive a pediatric priority review voucher (PRV) upon marketing approval.

The PRV is a valuable asset that can be used to expedite the FDA review of a future Biologic License Application or may be sold or transferred to another company. This designation, along with the previously granted Fast Track status, is designed to enhance engagement with the FDA and as many as possible accelerate the time to market for SGT-212.

The Current Landscape

Friedreich’s ataxia impacts as many as approximately 5,000 people in the United States and 15,000 in Europe. There are currently no treatments that provide a cure or halt disease progression, underscoring the high unmet medical need. SGT-212, as a recombinant AAV-based gene replacement therapy, aims to repair the underlying mitochondrial dysfunction in both neurons and cardiomyocytes by restoring FXN levels.