Novartis has announced promising topline results from the Phase III STEER study, which demonstrate the efficacy of intrathecal onasemnogene abeparvovec (OAV101 IT) in treating spinal muscular atrophy (SMA) in patients aged two to less than 18 years.

The study successfully met its primary endpoint, showing a significant increase in Hammersmith Functional Motor Scale - Expanded (HFMSE) total scores in patients treated with OAV101 IT compared to sham controls, indicating improved motor function.

The STEER study utilized validated assessments to evaluate the therapeutic effects of OAV101 IT on motor abilities and disease progression specific to SMA.

In terms of safety, the profile of OAV101 IT was comparable to the sham control, with common adverse events reported including upper respiratory tract infections, pyrexia, and vomiting.

SMA is a genetic neuromuscular disease caused by the absence of a functional SMN1 gene, which leads to the loss of motor neurons and significantly impacts muscle function.

Conducted as a randomized, double-blind, and sham-controlled trial, the STEER study involved over 100 patients who had never walked independently but were able to sit.

These findings build on previous research, including the Phase I/II STRONG study, which also indicated meaningful increases in HFMSE scores following treatment with OAV101 IT.

Dr. Shreeram Aradhye from Novartis highlighted the significance of these results for SMA patients reliant on chronic treatments, emphasizing the innovative gene therapy approach to restore the function of the missing SMN1 gene.

OAV101 IT represents the first investigational gene therapy to demonstrate clinical benefits in treatment-naïve SMA patients aged two and older, showcasing a favorable risk-benefit profile.

Looking ahead, Novartis plans to present the study results to regulatory agencies, including the US Food and Drug Administration (FDA), in 2025 to expedite the availability of OAV101 IT for SMA patients.