Zolgensma was previously granted breakthrough therapy designation by the US regulator. Novartis expects a regulatory action to be taken on the gene replacement therapy in May 2019.
According to Novartis, SMA Type 1, which results from a defective or missing SMN1 gene, is a deadly neuromuscular disease with very few treatment options.
Zolgensma, which is intended to be delivered as a single, one-time infusion, functions by replacing the missing or defective SMN1 gene with a functional copy that makes SMN protein. Through this mechanism, the gene therapy is said to help in enhancing motor neuron function and survival.
The investigational gene therapy was originally developed by AveXis, a US-based clinical stage gene therapy company, which was acquired by the Swiss drugmaker for $8.7bn in an all-cash deal this year.
In a phase 1 trial called START, all the 15 enrolled patients, who were infused with Zolgensma were alive and did not require any permanent ventilation at 24 months.
Further, 92% of patients, who were subjected to the proposed therapeutic dose of the gene therapy could sit on their own for more than five seconds, which is a milestone that was never achieved in the natural history of SMA Type 1, said Novartis.
AveXis president David Lennon said: “This important step by the FDA brings us ever closer to delivering Zolgensma to patients with SMA Type 1. 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.”
The gene therapy also has SAKIGAKE designation given by Japanese regulators with a decision on its New Drug Application (J-NDA) likely to come out in the first half of next year.
In Europe, it has been given the PRIority Medicines (PRIME) designation with a decision on its Marketing Authorization Application (MAA) expected to be taken in mid-2019.