Novartis New Data From Single-Dose Gene Therapy Shows Meaningful Efficacy, Safety In Patients With Spinal Muscular Atrophy

On Wednesday, Novartis AG NVS announced safety and efficacy results from the Phase 3 program for investigational intrathecal onasemnogene abeparvovec (OAV101 IT) in a broad population of patients aged two to <18 years with spinal muscular atrophy (SMA).

In the Phase 3 STEER study, treatment with OAV101 IT led to a statistically significant 2.39-point improvement on the Hammersmith Functional Motor Scale Expanded (HFMSE), an assessment of motor ability and disease progression, vs. 0.51 points in the sham control arm.

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Novartis released topline data from the Phase 3 STEER study in December 2024.

In the Phase 3b STRENGTH study, treatment with OAV101 IT in patients who have discontinued treatment with Biogen Inc’s BIIB Spinraza (nusinersen) or Roche Holdings AG’s RHHBY Evrysdi (risdiplam) demonstrated stabilization of motor function over 52 weeks of follow-up.

The results add to the growing body of evidence within the OAV101 IT development program, which has evaluated a broad population of over 170 patients with SMA, spanning a total of over 6.4 years across the STEER, STRENGTH, and Phase 1/2 STRONG studies.

OAV101 IT is an investigational gene replacement therapy designed to directly address the genetic root cause of the disease by replacing the nonworking SMN1 gene with a single dose.

In the registrational STEER study, efficacy and safety were studied in treatment naïve patients with SMA Type 2, aged two to less than 18 years, who could sit but had never walked independently. Key findings:

The trial met its primary endpoint of change from baseline to 52 weeks in HFMSE score, with OAV101 IT demonstrating a statistically significant 2.39-point improvement on the HFMSE vs 0.51 points in the sham group.
All secondary endpoints consistently favor OAV101 IT, despite not achieving statistical significance due to the pre-planned multiple testing procedure.

The open-label Phase 3b STRENGTH study evaluated the safety, tolerability and efficacy of OAV101 IT in patients with SMA aged two to less than 18 years who had discontinued treatment with nusinersen or risdiplam. Key findings:

OAV101 IT demonstrated a favorable safety profile that was consistent with the STEER study.
The motor endpoint of efficacy, HFMSE, demonstrated stabilization for the overall study population over 52 weeks. The increase from baseline to 52 weeks in HFMSE least squares (LS) total score was 1.05.

Price Action: NVS stock is down 0.75% at $111.38 at the last check Wednesday.

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