The US Food and Drug Administration (FDA) has approved onasemnogene abeparvovec-xioi (Zolgensma), as the first gene therapy for children younger than age 2 with spinal muscular atrophy (SMA).
The treatment has been approved for the spinal muscular atrophy caused by bi-allelic mutations in the survival motor neuron 1 (SMN1 ) gene. The gene encodes the SMN protein critical for the maintenance and function of motor neurons.
Zolgensma, manufactured by AveXis Inc, is an adeno-associated virus vector-based gene therapy that addresses the genetic root cause of SMA by replacing the defective or missing SMN1 gene to halt disease progression.
A one-time intravenous infusion of Zolgensma results in expression of the SMN protein motor neurons, which improves muscle movement, function, and survival, says FDA. Dosing will be considered based on the weight of the patient.
In the phase 3 STR1VE trial, Zolgensma was associated with prolonged event-free survival, increases in motor function, and significant milestone achievement in patients with SMA type 1 (acute infantile form).
“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,” said Peter Marks, MD, Ph D, director of the FDA’s Center for Biologics Evaluation and Research, in a news release.
“This approval demonstrates the continued momentum of this promising new area of medicine and the FDA’s commitment to supporting and helping expedite the development of these products,” he added.
However, according to the company, a one-time infusion of Zolgensma will cost more than $2 million, making it the world’s most expensive drug. The annualized cost of Zolgensma is $425,000 per year for 5 years.