(MEMPHIS, Tenn. – August 13, 2025) Spinal muscular atrophy (SMA), a rare genetic disorder causing progressive muscle weakness, has long posed a severe threat to infants, often leading to death before the age of two if untreated. However, a groundbreaking study led by an international consortium, including Dr. Richard Finkel of St. Jude Children’s Research Hospital, reveals that administering the oral drug risdiplam to newborns as early as 16 days old can significantly improve outcomes. The phase 2 clinical trial results, published in the New England Journal of Medicine, mark a pivotal advancement in the treatment of SMA.
Previously, risdiplam was approved by the Food and Drug Administration (FDA) for use in patients aged two months and older. The new findings suggest that earlier intervention, before symptoms appear, is both safe and effective. According to Dr. Finkel, “By age 2, we saw most of the children who we had treated were walking and in good general health,” highlighting the dramatic impact of early treatment.
Transformative Results for Infants
The trial involved infants with genetic mutations responsible for SMA, who began daily risdiplam treatment within the first six weeks of life. Conducted at multiple global sites, including Nemours Children’s Health in the U.S., the study followed 23 participants over two years. Among the eight children predisposed to the most severe form, SMA type 1, seven were able to sit by 12 months, and five could walk by the study’s conclusion, with no fatalities reported. For the 18 children with mutations predicting less severe disease, all achieved sitting by 12 months and walking by 24 months, aligning with typical developmental milestones. Importantly, no major treatment-related adverse events occurred.
Dr. Aledie Navas of Nemours Children’s Hospital, Orlando, emphasized the significance of these findings: “For families facing a diagnosis of SMA, the results of this study offer real hope. Treating children before symptoms appear — when they are still developing normally — can change the entire trajectory of the disease.”
Implications for SMA Treatment
SMA is characterized by the loss of specific neurons that activate muscles, leading to muscle atrophy. Risdiplam and similar treatments aim to prevent this atrophy, slowing disease progression. The study’s success in newborns suggests that early intervention can be crucial in altering the disease’s course. Dr. Finkel noted, “We’ve learned that it’s crucial to start the drug as soon as possible. Literally every day counts.”
While risdiplam is not a cure, its ability to slow disease progression offers substantial benefits. The RAINBOWFISH study, sponsored by F. Hoffman–LaRoche, continues to explore the drug’s efficacy and safety, building on previous studies in older patients. “The treatment of babies right after birth is an important milestone,” Dr. Finkel stated, adding that further research is underway to explore even earlier interventions, including prenatal treatment.
Continuing Research and Future Directions
Dr. Finkel and his team are already investigating the potential of administering risdiplam in the prenatal environment. Preliminary results from a phase 1 clinical trial, also published in the New England Journal of Medicine, indicate promising outcomes. The ongoing research aims to refine treatment strategies and provide children with SMA a chance at a normal life.
The study’s co-first author, Laurent Servais from the University of Oxford and University Hospital Liège, along with a team of international researchers, contributed to these findings. The research was supported by F. Hoffmann–La Roche Ltd, underscoring the collaborative effort to advance SMA treatment.
As the medical community continues to explore innovative approaches to SMA, the early administration of risdiplam represents a significant leap forward. The potential to alter the disease’s trajectory from birth offers hope to families worldwide, paving the way for further breakthroughs in the fight against this devastating condition.
