What the trial was testing
The STEER enrolled 126 patients with spinal muscular atrophy. The study was sponsored by Novartis Pharmaceuticals and tracked outcomes across the full group of patients who matched the trial's eligibility profile.
It was a large trial designed to confirm whether the treatment works well enough for wider use. Trials at this stage are designed to produce evidence regulators and physicians can act on — not just observations to follow up later.
What the results showed
Children receiving the gene therapy improved their motor skills by nearly 2 points more on a standard muscle function test.
Nature medicine · 2026 · NCT05089656
These findings — that children who got the gene therapy improved their ability to move nearly 2 points more than those who didn't — were published in the Nature medicine and represent the headline result of the study.
Researchers tracked outcomes across 126 patients enrolled in the trial. The result was consistent enough across the group that the team felt confident reporting it.
What this means for patients
For patients with spinal muscular atrophy, this result changes the calculus on what to ask their care team about. Whether it changes day-to-day care depends on factors like disease subtype, prior treatments, and where the patient is in their care journey.
What you can do now
This one-time gene therapy is FDA-approved for spinal muscular atrophy under the brand name Zolgensma, though this specific delivery method (through the spine) may have different approval status. If your child has spinal muscular atrophy, talk to your neuromuscular specialist about whether this treatment approach is available and appropriate for your child's specific situation.
Eligibility for the treatments mentioned above depends on specific test results and clinical history. Bring this summary, the trial name, and your most recent labs or pathology report to your next visit.
Open spinal muscular atrophy trials
Study of the Safety and Efficacy of an Adeno-Associated Viral Vector Carrying the SMN Gene After a Single Intravenous Administration of Escalating Doses in Children With Spinal Muscular Atrophy (BLUEBELL)
The goal of this multicenter, open-label, non-comparative, cohort study is to investigate the safety, immunogenicity, and efficacy of ANB-004 in children with spinal muscular atrophy. The study will have a standard 3+3 dose-escalation design.
A Long-term Safety Study in Brazilian Patients With a Diagnosis of Spinal Muscular Atrophy Treated With Zolgensma
A long-term safety study in Brazilian patients with a confirmed diagnosis of Spinal Muscular Atrophy (SMA) treated with Onasemnogene Abeparvovec (Zolgensma®)