The confirmation follows widespread concern among patient advocates who reported that families were being informed of the safety data through individual medical appointments rather than a unified public announcement. Dustin Brondyke, a parent of a child with SMA, noted on LinkedIn that he was informed at a neurologist appointment that the therapy was linked to two cases of children developing tumors, with seven additional cases likely tied to the product. Another parent, speaking anonymously, stated that the two confirmed cases appeared to occur 18 to 60 months after dosing. Novartis stated that the potential risk of tumors due to vector integration is already included in the Zolgensma prescribing information, which carries a warning about the theoretical risk of tumorigenicity stemming from the adeno-associated viral (AAV) vector used to deliver the survival motor neuron (SMN) protein.
SMA Europe, a patient advocacy organization, acknowledged the reports and stated that regulatory authorities are actively involved in assessing the available evidence. The organization indicated it has been informed of the situation through confidential channels and has urged Novartis to provide timely public communication to the SMA community. This development adds to existing safety scrutiny of the therapy, which previously faced concerns regarding liver-related adverse events. In 2021, an FDA advisory committee reviewed data showing that about one-third of the 500 patients treated at that time experienced liver-related adverse events, including one case of serious liver failure.
Novartis stated it continually evaluates new safety information and assesses all reported cases as part of its ongoing commitment to monitoring medicine safety. The two patients with evidence of vector integration have undergone treatment and continue to be monitored. The company did not provide specific details on the types of tumors or the current health status of the other seven patients. Regulatory agencies are currently determining what further steps may be needed based on the accumulating data.
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