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Spinal Muscular AtrophyFebruary 2026

What the STRENGTH Trial Found — Spinal Onasemnogene Abeparvovec for Older SMA Patients

STRENGTH tested intrathecal onasemnogene abeparvovec — a spinal-fluid version of Zolgensma — in 27 children and teens with SMA who had stopped nusinersen or risdiplam. The 52-week safety profile matched what was seen in younger, untreated patients.

What the trial was testing

The STRENGTH enrolled 27 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

0 deaths and 0 study discontinuations from side effects in 27 patients.

Nature Medicine · 2026 · NCT05386680

These findings — that and no discontinuations from side effects with spinal onasemnogene in 27 SMA patients — were published in the Nature Medicine and represent the headline result of the study.

Researchers tracked outcomes across 27 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

The intrathecal (spinal-fluid) form of onasemnogene abeparvovec is still in development and not yet FDA-approved as of early 2026. The IV form (Zolgensma) is FDA-approved for children under 2. Other approved SMA treatments include nusinersen (Spinraza) and risdiplam (Evrysdi). Ask a pediatric neurologist about approved options or open trials.

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.