Novartis reveals positive phase 3 results for spinal muscular atrophy gene therapy

Novartis has announced encouraging outcomes from its pivotal research on a promising gene replacement therapy targeted at spinal muscular atrophy (SMA), a rare neuromuscular condition. The phase 3 STEER trial has been investigating the effects of intrathecal onasemnogene abeparvovec (OAV101 IT) in individuals with SMA type 2, aged between two and 18 years, who have never walked independently but are able to sit.

The study successfully achieved its primary objective, demonstrating that patients treated with OAV101 IT experienced a statistically significant improvement of 2.39 points on the Hammersmith Functional Motor Scale Expanded. This scale is essential for assessing motor skills and tracking disease progression. In contrast, those undergoing a sham procedure saw only a 0.51-point enhancement.

Additionally, Novartis disclosed findings from the phase 3b STRENGTH study. This open-label research explored OAV101 IT in SMA patients, also between the ages of two to 18, who had stopped treatments with either nusinersen or risdiplam. Over a 52-week follow-up, the results indicated stabilization in motor function for these individuals.

Novartis noted that safety results were consistent across both groups of patients—those new to treatment and those with previous treatment experience. The company intends to submit regulatory applications for OAV101 IT within the year's first half. Shreeram Aradhye, the president of development and chief medical officer at Novartis, expressed optimism about the data, highlighting the therapy's potential to significantly impact people with SMA by providing ongoing benefits through a one-time dose.

SMA affects approximately one in every 10,000 infants worldwide and stems from a deficiency of a functional SMN1 gene. This deficiency leads to the irreversible degeneration of motor neurons, impairing muscle functionalities such as breathing, swallowing, and fundamental movements. Through a single spinal injection, OAV101 IT aims to address the genetic defect by substituting the nonfunctional SMN1 gene.

In the STEER study, OAV101 IT demonstrated a noteworthy improvement in motor functions among treatment-naïve patients across the broader SMA demographic, according to Crystal Proud, a pediatric neurologist and principal investigator at the Children’s Hospital of the King’s Daughters. Proud emphasized that these findings, combined with the STRENGTH study outcomes, underscore the potential of OAV101 IT as a viable treatment option for those with SMA. The goal is to maintain or enhance motor function through a single administration of the therapy.

This development could represent a significant advancement in the treatment landscape for SMA, offering hope to many individuals impacted by this challenging condition. By targeting the genetic cause of SMA, OAV101 IT may pave the way for new therapeutic strategies that could transform patient care. Through these studies, Novartis is moving closer to providing a groundbreaking treatment that might alter the course of SMA and improve the quality of life for countless patients worldwide.