FDA Accepts Application for Genetic Treatment of Spinal Muscular Atrophy Type 1
The Food and Drug Administration (FDA) has accepted the Biologics License Application for onasemnogene abeparvovec-xxxx (AVXS-101, Zolgensma; AveXis, Bannockburn, Illinois), an investigational gene replacement therapy for spinal muscular atrophy Type 1 (SMA1). SMA, which causes loss of motor neurons and progressive muscle weakness and paralysis, is caused by a genetic defect in the SMN1 gene that codes SMN, a protein necessary for the survival of the neurons. The FDA acceptance of the application is supported by data from the START trial (NCT02122952),which showed a dramatic increase in survival and improvement of children with SMA1 compared to the natural history of the disease.
None of the15 patients who were infused with AVXS-101 needed permanent ventilation at 24 months. After the therapy was delivered intravenously via single-dose infusion in children 0.9 to 7.9 months of age, 92% could sit unassisted for ≥ 5 seconds, a milestone never achieved in the natural history of SMA1. At the 24-month follow up, all 15 patients were event-free, as opposed to only 8% of patients in a natural history study. This indicates a clinically meaningful increase in survival for patients infused with AVXS-101 when compared to untreated patients.
Onasemnogene abeparvovec-xxxxhas received breakthrough therapy designation and granted priority review by the FDA, with regulatory action anticipated in May 2019. Delivered as a single, one-time infusion, this technology replaces the missing or defective SMN1 gene with a functional copy that makes SMN protein, which improves motor neuron function and survival.
“This important step by the FDA brings us ever closer to delivering Zolgensma to patients with SMA1,” said David Lennon, president of AveXis. “Babies affected by this rare disease are currently faced with debilitating disease progression and lifelong invasive chronic treatment. As a one-time infusion that addresses the genetic root cause of SMA without the need for repeat dosing, Zolgensma represents a potentially significant therapeutic advance for these patients and their families.”