Zolgensma improves motor function at 52 weeks in spinal muscular atrophy

Key takeaways:

• Motor function and other motor milestones were maintained or improved for most patients.
• All participants recorded at least one treatment-emergent adverse event, but no withdrawals or deaths were reported.

Treatment with Zolgensma improved motor function in a cohort of children with spinal muscular atrophy, according to a poster at the 2024 MDA Clinical & Scientific Conference.

“Clinical trials have demonstrated safety and efficacy of intravenous onasemnogene abeparvovec for patients with spinal muscular atrophy weighing less than 8.5 kg,” Hugh J. McMillan, MD, neurologist and neuromuscular specialist at the Children’s Hospital of Eastern Ontario, and colleagues wrote.

McMillan and colleagues sought to evaluate safety, efficacy and tolerability of Zolgensma (onasemnogene abeparvovec, Novartis) in the open-label, single-arm, multicenter, phase 3b SMART study over 52 weeks for patients weighing at least 8.5 to 21 kg, a heavier class of patients than in previous clinical trials.

A total of 24 participants (mean age 4.69 years; 21 of 24 discontinued another disease-modifying treatment prior to the study) were separated into three treatment cohorts based on weight: 8.5 kg to 13 kg (n = 7), more than 13 kg to 17 kg (n =8), more than 17 kg to 21 kg (n = 9).

According to results, by week 52, three participants achieved standing with assistance, one achieved independent standing and one achieved walking with assistance.

Data further showed that motor function as measured by the Revised Upper Limb Module (RULM) Hammersmith Functional Motor Scale – Expanded (HFMSE) and other motor milestones was maintained or improved for most patients. Mean change from baseline to study concussion was 2 for RULM and 3.7 for HFMSE.

All participants recorded at least one treatment-emergent adverse event, and seven of 24 participants had serious adverse events related to the study drug. Transaminase elevations were ongoing in 14 patients at the end of study, while frequency and severity of adverse events were similar across weight groups. No study withdrawals or deaths occurred.

“Most patients maintained or improved motor function, suggesting clinical benefit of intravenous onasemnogene abeparvovec for heavier patients with [spinal muscular atrophy],” McMillan and colleagues wrote.

Reference:

• Novartis presents new data on safety and efficacy of Zolgensma, including maintained and improved motor milestones in older and heavier children with SMA. https://www.novartis.com/news/media-releases/novartis-presents-new-data-safety-and-efficacy-zolgensma-including-maintained-and-improved-motor-milestones-older-and-heavier-children-sma. Posted March 4, 2024. Accessed March 4, 2024.