Novartis intrathecal onasemnogene abeparvovec Phase III study meets primary endpoint in children, young adults with spinal muscular atrophy

The STEER study met its primary endpoint showing an increase from baseline across the study population in total Hammersmith Functional Motor Scale - Expanded (HFMSE) scores. HFMSE is a gold standard for SMA-specific assessment of motor ability and disease progression. The increase was observed in patients treated with OAV101 IT compared to sham controls indicating better motor function in patients with SMA.

The safety profile of OAV101 IT was favorable. The overall adverse events and serious adverse events were similar between arms. 

Novartis plans to share results with regulatory agencies in 2025, including the US Food and Drug Administration (FDA), with the aim to make OAV101 IT available to help patients with SMA in need. Data will be presented at an upcoming medical meeting in 2025.

“Many patients with SMA currently rely on chronic treatments to manage their disease. These positive topline results from the STEER trial underscore the efficacy, safety and tolerability of OAV101 IT in patients with SMA aged two and above,” said Shreeram Aradhye, M.D., President, Development and Chief Medical Officer, Novartis. “The totality of evidence clearly supports a positive risk benefit profile of OAV101 which is expected to support registration covering a broad range of SMA patients. We remain committed to leading innovation in SMA treatment through our one-time gene therapies, uniquely designed to replace the function of the missing or defective SMN1 gene.”

“Maintaining motor function is a key goal for many older patients with SMA. This may allow them the capacity to continue to propel their electric wheelchair, feed themselves with intact hand to mouth function, and perform other activities of daily living as independently as possible” said Crystal Proud, M.D., Pediatric Neurologist and a Principal Investigator at Children's Hospital of the King's Daughters. "OAV101 IT administration has not only been demonstrated to maintain motor function, but also increased it in indicating the impact a one-time therapy could have.”

Results from STEER build on the Phase I/II open-label STRONG study which showed that treatment with OAV101 IT led to a clinically meaningful increase in HFMSE scores in one year, and a clinically meaningful response in patients aged two to five years with SMA Type 2, who were able to sit but had never walked independently. The results from the Phase III STEER study add to the clinical data and emerging real-world evidence for the use of one-time gene therapy to treat SMA.