Spinal muscular atrophy: no children affected by the adverse effects of Zolgensma, according to the National Medicines Safety Agency

No French child is affected by the serious adverse effects of Zolgensma, a drug already prescribed worldwide to more than 6,000 children affected by spinal muscular atrophy (SMA), the National Medicines Safety Agency (ANSM) told franceinfo on Friday November 13. Novartis, the laboratory which manufactures this drug described as a "miracle", announced last Friday to AFP that nine children who benefited from it around the world subsequently developed tumors.

Zolgensma is a gene therapy drug designed thanks to research by AFM Téléthon (funded by donations), developed and marketed by the Novartis laboratory since its marketing authorization in the United States in 2019, indicates franceinfo. It is described as "miraculous" because children with spinal muscular atrophy (SMA) show signs of recovery after just one injection. An observation that must be welcomed with caution to the extent that there is only a few years of hindsight.

Spinal muscular atrophy is a disease that prevents muscles from functioning and causes death in the most severe cases. It has been detected at birth since September 1, 2025 in France, where, to date, 229 newborns treated with Zolgensma are now living normally, without symptoms of the disease.

The risk of developing cancer is one of the serious side effects already known from Zolgensma, the ANSM tells franceinfo. On November 6, the Novartis laboratory indicated that in seven years, of the 6,000 children treated worldwide, nine cases of tumors had been identified, without however specifying the type of cancer. According to information from franceinfo, these are cancers of the nervous system and kidneys.

The ANSM indicates to franceinfo that no French child is affected by these serious adverse effects at this stage and that the European Medicines Agency is launching a new evaluation of Zolgensma. This assessment should make it possible “to characterize this risk and in particular the types of tumors concerned, the time frames for occurrence as well as possible contributing factors and implications in terms of long-term monitoring”, specifies the ANSM which “participates in this assessment”.

According to the French and American health authorities, as well as the AFM Téléthon, the benefits of Zolgensma remain greater than the risk of developing serious adverse effects. “No change in patient care or monitoring is recommended,” according to the National Medicines Safety Agency which, it concludes with franceinfo, “maintains reinforced surveillance of the drug.”