Instead of immediately releasing functional data to satisfy investors and social media, Solid Biosciences is strategically withholding it. The company will first share the analysis with the FDA to align on an accelerated approval pathway, believing this professional courtesy builds a stronger regulatory relationship and improves the long-term outcome.
For its Friedreich's ataxia program, the company uses a dual-route administration to deliver the gene therapy to the dentate nucleus of the cerebellum, the spinal column, and the heart. This comprehensive approach is designed to meet patients at any stage of their disease, addressing both central nervous system and cardiac symptoms with a single treatment.
The CEO advises against trying to resolve all regulatory issues in a single FDA meeting. Instead, Solid Biosciences uses a series of three focused, one-hour meetings. Each meeting targets only a few key questions, allowing for in-depth discussion and ensuring concrete alignment on specific points before moving to the next stage.
Beyond common biomarkers, Solid Biosciences emphasizes embryonic myosin heavy chain. A decrease in this marker suggests muscle stability and preservation of the satellite cell pool, which is depleted in Duchenne patients. The company believes this is more predictive of long-term functional benefit than traditional measures like CK or Western blot.
The CEO predicts the future of Duchenne muscular dystrophy treatment will involve combination therapy. Rather than one gene therapy replacing all other drugs, he expects a future where gene therapies are used alongside exon-skipping drugs. Payer research indicates willingness to cover both if the gene therapy shows at least three years of durability.
While monitoring cardiac health for safety, Solid Biosciences observed a potential efficacy signal. In young patients with low-to-normal ejection fractions, the therapy appears to reverse a downward 'drift' over time, returning them to a normal range. This suggests a long-term cardioprotective benefit, even before a formal cardiomyopathy diagnosis would typically occur.