Novartis Reports 9 Tumours in Zolgensma Patients as FDA Investigates

The US Food and Drug Administration is investigating reports of tumours in patients treated with Zolgensma, the spinal muscular atrophy (SMA) gene therapy sold by Novartis. Novartis said nine tumours have been reported in patients treated with the therapy.

What happened

In a safety notice dated Nov. 6, the FDA said it had received postmarketing reports of malignancies in SMA patients who received Zolgensma. The reported tumours were in the central and peripheral nervous system, the spine and nearby tissue, and the kidney.

Three cases involved tumours tied to GLI1, a gene that can drive cancer. In two of them, the FDA said tumour testing found the therapy's viral vector DNA had integrated into the patient's genome near or inside GLI1. The cause in the third case is still under review.

Novartis confirmed the nine reported tumours in a statement on Nov. 5, BioSpace reported. The company said two cases showed evidence of vector integration, and that those patients were treated and are still being monitored. According to BioSpace, the other seven reports have not been causally linked to the therapy.

The patient group Cure SMA said three of the nine tumours have been tested so far, and one of those appears unrelated to Zolgensma, according to BioPharma Dive.

Why it matters

Zolgensma is an infusion approved in 2019 for SMA patients under 2 years old. Novartis said more than 6,000 patients have been treated across trials, managed access programs and commercial use. BioPharma Dive reported that the therapy earned $1.1 billion in the first nine months of 2026.

The FDA said the risk also applies to Itvisma, a newer Novartis therapy that uses the same vector and construct. Itvisma is given as a spinal injection to patients 2 years and older. The FDA said no tumours have been reported after Itvisma so far.

The agency said the benefits of both products still outweigh their potential risks for their approved uses. It is weighing whether regulatory action is needed and is reviewing the label and Novartis's long-term safety studies. The US label already warns of a theoretical tumour risk from vector integration.

The FDA also cited two journal reports from 2026 that linked vector integration to tumours in two other experimental gene therapy programs.

What it means for people in the industry

For now, the FDA says patients and trial participants who received either therapy should be monitored for tumours. No regulatory action has been announced yet.

What to watch next: whether the FDA changes the Zolgensma or Itvisma labels, takes other action, or asks for more long-term safety data. People working in gene therapy safety, pharmacovigilance and regulatory affairs will be following the review closely.

This is a news report, not medical advice. Patients and families with questions should speak with their care team.

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Sources

• FDA Investigating Serious Risk of Malignancy Linked to Zolgensma Gene Therapy, US Food and Drug Administration
• Novartis reveals cancer cases possibly linked to gene therapy Zolgensma, BioPharma Dive
• Update: FDA investigates Novartis' Zolgensma following 9 cases of tumors in treated patients, BioSpace