Novartis has shared positive top-line results from a late-stage study of its investigational gene therapy in patients aged two to less than 18 years with the rare neuromuscular disease spinal muscular atrophy (SMA).
The phase 3 STEER study has been evaluating intrathecal onasemnogene abeparvovec (OAV101 IT) in treatment-naïve patients with SMA type 2 who were able to sit but had never walked independently.
Results were compared against a sham control, which is designed to mimic the administration of an investigational drug without delivering any active treatment.
The trial met its primary endpoint, with OAV101 IT demonstrating an increase from baseline in total Hammersmith Functional Motor Scale – Expanded (HFMSE) scores, used to assess motor ability and disease progression, compared to sham control.
The safety profile of OAV101 IT was also shown to be favourable, and the overall adverse and serious adverse events were similar between arms, according to Novartis.
Affecting an estimated one in 10,000 infants globally, SMA is caused by a lack of a functional SMN1 gene and results in the loss of motor neurons.
The disease affects muscle functions such as breathing, swallowing and basic movement and its severity varies across a spectrum of types. Type 2 occurs in approximately 30% of all SMA patients who, if left untreated, will never walk without support and will need a wheelchair or other mobility aids.
OAV101 IT, which is administered as a one-time injection into the spine, uses a genetically engineered adeno-associated virus serotype 9 to deliver a working copy of the SMN1 gene into cells.
Shreeram Aradhye, president, development and chief medical officer, Novartis, said: “Many patients with SMA currently rely on chronic treatments to manage their disease.
“These positive top-line results from the STEER trial underscore the efficacy, safety and tolerability of OAV101 IT in patients with SMA aged two and above.”
The results build on those from the phase 1/2 STRONG study, in which OAV101 IT was associated with a clinically meaningful increase in HFMSE scores in one year, as well as 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.
Novartis said it is planning to share results for OAV101 IT with regulatory agencies, including the US Food and Drug Administration, this year.