Health

FDA investigates tumor risk in Novartis gene therapy Zolgensma after cancer gene activation confirmed

Washington • November 8, 2026 • By Press Pass USA

A scientist in a laboratory holding a vial of gene therapy, with a DNA helix in the background

Illustration: Press Pass USA

The Food and Drug Administration said Friday it is investigating a serious risk of tumors linked to Novartis' gene therapy Zolgensma, after tests confirmed that the therapy's viral vector switched on a cancer-driving gene in some children treated for spinal muscular atrophy.

Novartis disclosed on Thursday that it had received nine reports of tumors in patients previously treated with Zolgensma since the therapy was first approved in the United States in May 2019. Three of those cases involved the GLI1 oncogene, a gene that can drive cancer when it is switched on abnormally. In two of the three, analysis of tumor tissue confirmed that Zolgensma's viral vector DNA had integrated into the patient's genome near the GLI1 gene — a form of product-related insertional oncogenesis. The mechanism behind the GLI1 overexpression in the third case remains under investigation, the FDA said.

The tumors reported across the nine cases involved the central and peripheral nervous systems, the spinal and paraspinal regions, and the kidney, according to the FDA. Novartis said the two patients with confirmed vector integration received treatment for their tumors and remain under medical monitoring.

The FDA said the risk also applies to Itvisma, Novartis' newer gene therapy for spinal muscular atrophy, because it uses the same vector and construct as Zolgensma. Zolgensma is given by intravenous infusion to children under 2 years old with spinal muscular atrophy, while Itvisma is given by injection into the spinal canal to patients 2 years and older and was approved in November 2025. No cases of tumor formation have been reported after Itvisma treatment to date, the FDA said.

Spinal muscular atrophy is a rare genetic disease that weakens muscles, and Zolgensma — a one-time gene therapy — has been given to thousands of children worldwide since its approval.

The FDA said the overall benefits of both therapies continue to outweigh their potential risks for their approved uses, but it is evaluating whether regulatory action is appropriate. The agency said it is expeditiously reviewing whether the current prescribing information and the long-term follow-up studies Novartis is conducting are adequate to investigate and mitigate the risk. The current prescribing information describes only a "theoretical risk of tumorigenicity due to integration of AAV vector DNA into the genome."

The FDA advised health care providers to monitor patients treated with Zolgensma for tumor formation and to report suspected cases to Novartis Gene Therapies or to the FDA's MedWatch program.

Sources: U.S. Food and Drug Administration, “FDA Investigating Serious Risk of Malignancy Linked to Zolgensma Gene Therapy” (Nov. 6, 2026); Reuters, “FDA investigates tumour risk tied to Novartis gene therapy” (Nov. 6, 2026); TradingView News (dpa-AFX), “FDA Investigates Cancer Risk Associated With Novartis' Zolgensma Gene Therapy” (Nov. 7, 2026).