Novartis said Monday that the FDA granted priority review to an application seeking approval of Zolgensma (onasemnogene abeparvovec) for the treatment of spinal muscular atrophy (SMA) Type 1, with the agency setting a target data in May next year. The one-time gene replacement therapy, formerly known as AVXS-101, is designed to address the genetic root cause of SMA Type 1.

The drugmaker noted that in Japan, where Zolgensma has SAKIGAKE designation, a decision by regulators on a filing is expected in the first half of 2019, while in Europe, where the therapy has PRIME status, a decision on the submission is scheduled for mid-2019.

The filings are supported by data from the START trial, which demonstrated an increase in survival and improvement in achievement of developmental milestones compared to the natural history of SMA Type 1. Specifically, all 15 patients infused with Zolgensma were alive and without the need for permanent ventilation at 24 months, while 92 percent of those who received the proposed therapeutic dose of the therapy could sit unassisted for at least 5 seconds.

Last month, Novartis, which gained Zolgensma via its purchase of AveXis for $8.7 billion in April, suggested that the gene therapy could be cost-effective to healthcare systems at $4 million to $5 million per patient. David Lennon, president of AveXis, said Monday "the introduction of one-time, potentially curative therapies will require rethinking how our healthcare system manages diagnosis, treatment, care and associated costs for patients with genetic disease."

For related analysis, see ViewPoints: Something old, something new - Can Novartis convince payers that greater biosimilar adoption will loosen the purse strings for innovative therapies?