The US Food and Drug Administration approved onasemnogene abeparvovec-brve (Itvisma) for patients 2 years and older with spinal muscular atrophy caused by a confirmed SMN1 mutation. This is the first gene replacement therapy available across pediatric, adolescent, and adult age groups. The one-time intrathecal injection delivers a working SMN1 gene intended to support motor function through ongoing SMN protein production.

Approval was supported by the Phase 3 STEER study and the open-label Phase 3b STRENGTH study. Across both trials, the therapy produced statistically significant improvements in motor function and stabilization of motor abilities that are not typically observed in the natural history of the disease. These effects were sustained through 52 weeks of follow-up. The safety profile was consistent between studies. In STEER, the most common adverse events were upper respiratory tract infection and fever; in STRENGTH, the most common were common cold, fever, and vomiting.

Approximately 9,000 patients in the US are affected, and despite available disease-modifying therapies, unmet needs remain for older children, teens, and adults. A one-time gene replacement approach may reduce reliance on chronic treatment in these populations.

Itvisma will become available in December. Novartis will provide patient support services to assist with treatment initiation, insurance navigation, and financial resources. The therapy is administered as a single intrathecal injection and does not require adjustment based on age or body weight.

Source: Novartis