The Food and Drug Administration has approved Zolgensma (onasemnogene abeparvovec-xioi), the first gene therapy for the treatment of infantile-onset spinal muscular atrophy in children aged less than 2 years.
The FDA granted the approval of Zolgensma to AveXis Inc.
Spinal muscular atrophy (SMA) is a genetic disorder caused by a mutation in the SMN1 gene, which encodes the survival motor neuron protein. This protein is necessary for motor function throughout the body; without it, motor neurons die, causing severe, often fatal muscle weakness. Infantile-onset SMA is the most severe and most common form of the disease; children will have difficulty holding their head up, swallowing, or breathing. Symptoms can be present at birth or appear by 6 months.
FDA approval of Zolgensma is based on results of a pair of clinical trials – one ongoing, one completed – comprising 36 patients with infantile-onset SMA aged between 2 weeks and 8 months at study entry. Of the 21 patients initially enrolled in the ongoing trial, 19 remain, aged between 9.4 and 18.5 months; most of these patients are at least 14 months. Compared with natural disease course, patients treated with Zolgensma are more likely to reach developmental motor milestones such as head control and the ability to sit without support.
The most common adverse events associated with Zolgensma include elevated liver enzymes and vomiting. The labeling includes a warning that acute serious liver injury can occur, and patients with preexisting liver conditions are at a higher risk for serious liver injury. Liver function should be monitored for at least 3 months following initiation of Zolgensma treatment.
“Children with SMA experience difficulty performing essential functions of life. Most children with this disease do not survive past early childhood due to respiratory failure. Patients with SMA now have another treatment option to minimize the progression of SMA and improve survival,” Peter Marks, MD, PhD, director of the FDA’s Center for Biologics Evaluation and Research, said in the press release.
Find the fullon the FDA website.