Novartis Reports 9 Tumor Cases After Zolgensma Gene Therapy
Key Facts
Novartis said it had received 9 reports of tumors in patients previously treated with Zolgensma since the therapy was first approved in 2019, according to a statement the company provided to the SMA UK group on November 5. It said two of the reports showed evidence that the therapeutic vector DNA had integrated into patients’ DNA. The update distinguishes the number of reports on record from the cases in which evidence of integration was found; the nine reports do not mean a causal link to the treatment has been established in every case. The company said the two patients in the integration cases had received the treatment and remained under monitoring. The announcement puts the safety of the gene therapy used for spinal muscular atrophy at the center of ongoing monitoring, as cases continue to be reviewed and health authorities contacted.
In an update issued on November 4, England’s national multidisciplinary team for Zolgensma said histological examination had been completed for tumors in 3 of the nine children. The team concluded that two tumors among those three cases were specifically linked to the treatment, while the third appeared unrelated. The histology results provide further detail on some reports, but do not determine the status of the six other cases for which examination had not been completed, according to the update. This description differs from Novartis’ announcement of vector DNA integration evidence in two cases; each statement has its own scope and method of presenting the results. The key figures in the two disclosures therefore remain 9 reports, histology results for three cases, and two tumors that the English team described as linked to the treatment.
Novartis said more than 6,000 patients had received Zolgensma through clinical trials, access programs and commercial use, as of its November 5 statement. That figure puts the nine reports in the context of the patient population treated, without changing what the examination results mean for each case. The U.S. Food and Drug Administration approved Zolgensma on May 24, 2019, to treat pediatric patients under age 2 with spinal muscular atrophy and mutations in both copies of the SMN1 gene. The drug treats the disease through gene therapy, making integration of vector DNA into a patient’s genome part of the regulatory discussion around tumor risk. The reported cases remain under review in light of the number of patients treated and the individual results available.
Zolgensma’s FDA-approved prescribing information describes the risk of tumor formation from integration of AAV vector DNA into the genome as theoretical. The label says tumor analyses have not established a causal relationship with the treatment, while noting that information is limited in some cases. It also calls for reporting tumors in people who have received Zolgensma and directs health care providers to contact Novartis if a tumor develops in a treated patient. The existing warning places the new cases within a safety-monitoring framework set out in the drug information. STAT reported that the disclosure raised concerns among families, doctors and advocacy groups after the company acknowledged seven previously unknown cases in children who had received the treatment.
Novartis said it had appropriately and promptly reported each case to health authorities and would continue working with them on next steps. STAT quoted SMA Europe as saying regulators were reviewing the cases. Novartis had informed neurologists of the information earlier in the week, before advocacy groups publicly released the details, according to STAT. In the English team’s update, officials said information about the children was limited and that they were not currently recommending changes to usual care or monitoring, or additional tests. Continued case monitoring and contact with regulators are the next steps the company announced, while the English team has so far made no recommendation to change care.
Novartis shares, listed under the ticker NVS, closed at $161.93 on November 5, 2026, according to L7 data. The closing price is part of the session details for the day the disclosure was issued; no documented daily trading range is available in the evidence used here. The closing data alone do not explain the share move or show whether the disclosure affected it. The health announcement focuses on reports, examination results and patient monitoring, while the company said it would continue working with health authorities. The English team, meanwhile, left its recommendation on care and routine monitoring unchanged for now.