🧬 New tumor data published for patients treated with Zolgensma
Published 06 November 2026
Last update 06 November 2026
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The SMA UK website has published a statement from the UK national multidisciplinary Zolgensma team dated 4 November and a statement from Novartis dated 5 November 2026 on new safety data for the gene therapy for spinal muscular atrophy (SMA).
What is known so far
Since the product's first approval in 2019, Novartis has received 9 reports of tumours in previously treated patients. In total, more than 6,000 people have received Zolgensma in clinical trials, access programmes, and commercial practice.
According to UK specialists, tumour investigations have been completed in three children:
— two tumours are described as therapy-related;
— one tumour — as presumably unrelated.
Results for the remaining six cases are not presented in the statement.
What the manufacturer reports
Novartis uses more cautious wording, reporting the detection of viral vector DNA integration into patients' DNA in two cases.
Both patients received treatment for tumours and continue to be followed up. The company notes that the potential risk of tumorigenesis due to vector integration is already reflected in the product's prescribing information.
Important: the statement does not mean that all nine tumours were caused by Zolgensma. The tumour types, time of onset, and detailed investigation results are not disclosed in the publication.
According to Novartis, health authorities were notified of each case in a timely manner. Further information from regulators is expected.
Should patient monitoring change?
At this stage, the UK multidisciplinary team does not recommend changing standard monitoring or conducting additional investigations based on the available information.
Families with questions are advised to contact their treating specialists.
Why this matters
This situation once again highlights the importance of systematic collection of real-world clinical data and long-term follow-up of patients receiving gene therapy.
Mandatory inclusion of such patients in registries, with subsequent tracking of treatment efficacy and safety, will make it possible to identify rare and delayed adverse events in a timely manner and to refine the benefit-risk balance.
Source: SMA UK — statements from the UK multidisciplinary team dated 4 November and from Novartis dated 5 November 2026.
What is known so farSince the product's first approval in 2019, Novartis has received 9 reports of tumours in previously treated patients. In total, more than 6,000 people have received Zolgensma in clinical trials, access programmes, and commercial practice.
According to UK specialists, tumour investigations have been completed in three children:
— two tumours are described as therapy-related;
— one tumour — as presumably unrelated.
Results for the remaining six cases are not presented in the statement.
What the manufacturer reportsNovartis uses more cautious wording, reporting the detection of viral vector DNA integration into patients' DNA in two cases.
Both patients received treatment for tumours and continue to be followed up. The company notes that the potential risk of tumorigenesis due to vector integration is already reflected in the product's prescribing information.
Important: the statement does not mean that all nine tumours were caused by Zolgensma. The tumour types, time of onset, and detailed investigation results are not disclosed in the publication.
According to Novartis, health authorities were notified of each case in a timely manner. Further information from regulators is expected.
Should patient monitoring change?At this stage, the UK multidisciplinary team does not recommend changing standard monitoring or conducting additional investigations based on the available information.
Families with questions are advised to contact their treating specialists.
Why this mattersThis situation once again highlights the importance of systematic collection of real-world clinical data and long-term follow-up of patients receiving gene therapy.
Mandatory inclusion of such patients in registries, with subsequent tracking of treatment efficacy and safety, will make it possible to identify rare and delayed adverse events in a timely manner and to refine the benefit-risk balance.
Source: SMA UK — statements from the UK multidisciplinary team dated 4 November and from Novartis dated 5 November 2026.
