Key facts
- The FDA said it was investigating a risk of neoplasia, including malignancy, associated with Novartis's Zolgensma gene therapy.
- Novartis said it had received nine reports of tumors in patients previously treated with Zolgensma.
- Novartis said two of the nine cases showed evidence the therapy's vector DNA had integrated into patients' DNA.
- Novartis said the potential risk from vector integration is already included in Zolgensma's prescribing information.
- SMA Europe said regulators are now reviewing the reports, according to Clinical Observer.
The US Food and Drug Administration said on Friday, November 6, 2026, that it was investigating a risk of neoplasia, or tumor formation including malignancy, associated with Novartis's gene therapy Zolgensma, which is used to treat patients under two years old with spinal muscular atrophy.
Earlier the same day, Novartis disclosed two cases in which tumors in children showed evidence of being linked to the therapy. The company said it had received nine reports overall of tumors in patients previously treated with Zolgensma, and that two of those cases showed evidence that DNA from the therapy's viral vector had integrated into patients' DNA, according to STAT.
Seven of the nine reports were new disclosures, STAT reported. Novartis said the two patients with evidence of integration underwent treatment and continue to be monitored, and that the potential risk from vector integration is already included in Zolgensma's prescribing information.
The cases are being treated as a possible safety signal rather than as proof that the therapy caused the tumors, and no conclusion has been reached, according to Clinical Observer. The advocacy group SMA Europe and a Facebook page made the cases public on Thursday, and SMA Europe said regulators are now reviewing the reports. BioPharma Dive reported that Cure SMA said three of the nine patients had their tumors tested, and one tested case appeared unrelated to Zolgensma.