Zolgensma (AVXS-101, onasemnogene abeparvovec) is designed to address the genetic cause of spinal muscular atrophy.

Spinal muscular atrophy (SMA) results from a deficiency in the protein survival motor neuron (SMN), which occurs when a mutation is present in both copies of the SMN1 gene. In some cases, neighboring SMN2 genes produce full-length, functional SMN protein, and onset of the disease tends to occur later in people with more copies of the SMN2 gene. 

There are four types of SMA. In SMA type 1 (also known as infantile onset or Werdnig–Hoffmann disease), symptoms are observed at birth or within the first 6 months of life. More than 50% of new SMA cases are SMA type 1. Respiratory muscle weakness is the most significant problem and the most common cause of death in patients with SMA type 1. Use of portable ventilation devices can help in some cases; in others, a tracheotomy is necessary. Insufflator–exsufflator and high-frequency chest wall oscillation devices may also be required. 

A new drug being developed by Novartis may transform treatement. Zolgensma (AVXS-101, onasemnogene abeparvovec) is designed to address the genetic root cause of SMA type 1. It is a one-time infusion that requires no repeat dosing and represents a potentially significant therapeutic advance, according to David Lennon, president of Novartis company AveXis.

Novartis’ Biologics License Application for Zolgensma was recently accepted for review by the U.S. Food and Drug Administration and granted priority review. Under the priority review program, applications are reviewed in six months or less, compared with 10 months for standard applications. 

The acceptance was based on the results of a clinical study of 15 patients. All of the patients infused with Zolgensma were able to go without permanent ventilation at 24 months. In addition, 92% of patients could sit unassisted for five seconds or more, which has never before been reported for babies with SMA type I, according to Novartis.