CHICAGO, Aug. 14, 2025
Early Intervention Transforms Spinal Muscular Atrophy Outcomes
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Giving a new drug for spinal muscular atrophy before symptoms appear yields life-changing results for infants.
Could treating babies for spinal muscular atrophy (SMA) before they even show symptoms dramatically alter their future? New findings suggest the answer is a resounding yes.
For infants with the most severe form of SMA, not receiving treatment typically means they never learn to sit and often succumb to the disease before their second birthday. But a groundbreaking clinical trial has demonstrated that administering the oral drug risdiplam as early as 16 days of age, before any signs of the condition emerge, is both safe and effective.
- Administering risdiplam to infants with SMA as early as 16 days old is safe and effective.
- By age 2, most treated children could walk and were in good health.
- No fatalities were observed in the study group with the most severe form of SMA.
- The U.S. Food and Drug Administration has expanded risdiplam’s approved age range based on these findings.
Transformative Treatment for SMA
The phase 2 clinical trial results, published in the New England Journal of Medicine, painted a vivid picture of the drug’s impact. “The impact of giving risdiplam soon after birth is quite dramatic,” said Richard Finkel, MD, co-first and corresponding author of the study.
Finkel, now director of the Center for Experimental Neurotherapeutics and a member of the Department of Pediatric Medicine at St. Jude Children’s Research Hospital, initiated the international consortium and participated in the study as a faculty member at Nemours Children’s Health. “By age 2, we saw most of the children who we had treated were walking and in good general health,” he added.
Early Action, Lasting Benefits
Babies born with genetic mutations that cause SMA were started on daily risdiplam within the first six weeks of life, crucially before definitive symptoms appeared. These infants were then followed for two years. The multicenter trial included 23 patients who completed the study, with participation at sites worldwide, including Nemours Children’s Health in the U.S.
Among the eight infants genetically predisposed to the most severe form of SMA, type 1, an astonishing seven were able to sit independently by 12 months. Furthermore, five of these infants could walk by the study’s two-year mark, with no reported fatalities.
For the 18 infants who had a mutation predicting less severe disease, all achieved the milestone of sitting by 12 months and walking by 24 months. Many reached these developmental goals within timeframes comparable to typically developing children. Importantly, none of the children experienced any major treatment-related adverse events.
Did you know? Spinal muscular atrophy is a rare genetic condition that causes progressive muscle weakness.
Hope for Families
“For families facing a diagnosis of SMA, the results of this study offer real hope,” stated contributing author Aledie Navas, MD, FAAP, FCCP, of Nemours Children’s Hospital, Orlando. “Treating children before symptoms appear — when they are still developing normally — can change the entire trajectory of the disease.”
Navas emphasized the shift in approach: “We are no longer just managing symptoms; we are preserving strength, function and quality of life from the very start.”
Finkel confirmed the drug’s positive impact on the regulatory front. “We demonstrated in this study that with treatment shortly after birth, risdiplam maintained a good safety profile and generated a favorable clinical response,” he said. “I’m pleased to say that data from this study led the Food and Drug Administration to change the label for risdiplam’s use, extending it to younger children.”
