FDA Approves Novartis’ Itvisma As The First Gene Therapy For Older Children, Teens, And Adults With SMA

Novartis announced that the FDA has approved Itvisma® (onasemnogene abeparvovec-brve) for treating children aged two and older, adolescents, and adults with spinal muscular atrophy (SMA) caused by a confirmed SMN1 gene mutation. This marks the first time a gene replacement therapy is available for such a wide SMA population. Itvisma delivers a one-time fixed dose, regardless of age or body weight, designed to replace the missing SMN1 gene and improve motor function, potentially reducing the reliance on continuous, long-term SMA treatments.

“The FDA’s approval of intrathecal onasemnogene abeparvovec is a game-changing advance, expanding the use of transformational gene replacement therapy for SMA across age groups,” said John W. Day, MD, PhD, Professor of Neurology and Paediatrics, Director, Division of Neuromuscular Medicine at Stanford University School of Medicine, and Co-Director of Stanford’s Neuro IGNITE Centre. “This achievement is not only a significant step forward for SMA – it also signals new possibilities for the broader field of neurological disorders and genetic medicine.”

The approval is supported by results from the Phase III STEER and Phase IIIb STRENGTH studies. Across both trials, Itvisma produced statistically meaningful improvements in motor function and helped stabilize motor abilities not typically maintained in the natural progression of SMA, with benefits sustained for at least 52 weeks. The therapy also demonstrated a consistent safety profile, with the most common adverse events including upper respiratory infections, fever, vomiting, and common colds.

“This new route of administration for a single dose of gene replacement therapy can mean so much more than what is measured by numbers on a functional motor scale – it could mean greater independence and freedom in activities of daily life,” said Kenneth Hobby, President, Cure SMA. “The SMA disease landscape has dramatically changed over the last six years, when the first gene therapy was approved. This is another welcome advancement, and it represents real progress in expanding access for many older patients and addressing the unmet needs that remain in our community.”

SMA is a rare genetic neuromuscular condition caused by the absence or mutation of the SMN1 gene, resulting in insufficient SMN protein and progressive loss of motor neurons. While individuals with additional copies of the SMN2 gene may experience a milder form of the disease, approximately 9,000 people in the U.S. live with SMA, and treatment gaps remain—especially for older children, teens, and adults. Itvisma aims to address these unmet needs by preserving motor neurons and maintaining muscle strength through targeted gene replacement.