Novartis' Zolgensma: Nine Cancer Cases Under Investigation in Children After Gene Therapy

Novartis' gene therapy Zolgensma, which targets spinal muscular atrophy (SMA), is currently under investigation by the U.S. Food and Drug Administration (FDA) following reports of nine cancer cases among treated children. This therapy has been available in the U.S. since 2019 and in Europe since 2020 for children under two years old. According to the patient organization SMA Europe, over 6,000 patients have been treated with Zolgensma since its approval, with the FDA now examining the reports of tumors that have emerged post-treatment.

Gene Therapy and Cancer Risk

Zolgensma aims to address the genetic cause of SMA by delivering a healthy copy of the SMN1 gene through a single intravenous infusion. The therapy utilizes modified, harmless viruses known as AAV vectors to transport the gene into the patient's cells. Reports indicate that the tumors affected the central and peripheral nervous systems, the spinal area, and the kidneys. In two instances, DNA from the virus used in the therapy was found in tumor tissue.

Both patients are under treatment and ongoing monitoring, as stated by SMA Europe, referencing Novartis. The company has emphasized that it has always warned about potential tumor risks in the product information for Zolgensma. The FDA is closely monitoring tumor risks associated with other similar AAV vector-based gene therapy programs, as highlighted in recent publications.

Ongoing Evaluation of Therapy Benefits

While the FDA assesses whether regulatory actions are necessary, it maintains that the benefits of Zolgensma therapy outweigh the potential risks. Toni Cathomen, director of the Institute for Transfusion Medicine and Gene Therapy at Freiburg University Hospital, noted that while the mechanism is not surprising, this is the first instance of an approved and widely used product showing such effects. He emphasized that the long-term cancer risk cannot be reliably quantified, as the nine tumor reports among over 6,000 treated patients do not yield a dependable risk rate.

Cathomen stressed the importance of transparent data and long-term follow-up in evaluating the therapy's risk-benefit profile, stating that Zolgensma significantly impacts the survival and motor development of SMA patients, while families must be informed about the cancer risks and treatment alternatives.