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Important context: This is a newly identified serious safety signal under investigation, not a recall, treatment withdrawal, a known percentage risk, or a recommendation to stop medical care. The FDA states that the overall benefits of both products continue to outweigh their potential risks for approved uses.
What did the FDA announce on November 6?
FDA received postmarketing adverse-event reports of tumors (neoplasia) in people treated with Zolgensma, an adeno-associated virus (AAV) gene therapy for spinal muscular atrophy (SMA). Reports include tumors involving central and peripheral nervous systems, spinal or paraspinal areas, and kidney. Not all tumors are necessarily cancers, and the reports alone cannot establish how frequently tumors occur.
Three reported tumor cases involved the GLI1 oncogene. In two, molecular analysis of tumor tissue demonstrated integration of the treatment's AAV vector DNA with the product's promoter positioned upstream of or within GLI1. FDA described this as confirmed product-related insertional oncogenesis. The mechanism in the third GLI1-associated tumor remains under investigation. These findings go beyond the purely theoretical risk previously described in labeling, but do not measure a population-wide cancer rate.
Which products and age groups are involved?
ZOLGENSMA · FDA APPROVED 2019
Children younger than 2
Approved for pediatric patients under age two with qualifying SMN1-related SMA. Delivered through a one-time intravenous infusion. Tumor reports after treatment prompted FDA's safety investigation.
ITVISMA · FDA APPROVED 2025
Ages 2 and older
Approved for adults and children ages two and older with the specified SMN1 mutation, administered into the spinal canal. It contains the same AAV vector and construct; FDA had received no tumor reports after Itvisma as of November 6.
The FDA considers tumor risk potentially relevant to both products because they share the vector and construct, even though their administration and patient groups differ. A zero reported case count for Itvisma does not establish zero risk.
What is known versus still uncertain?
Established information from the FDA notice
- Two Zolgensma-associated tumor samples showed integration of the viral vector near or in GLI1, supporting a product-related mechanism.
- The FDA is reviewing whether prescribing information, risk controls or regulatory action need to change.
- Long-term follow-up safety studies are being conducted, and FDA says patients receiving these products should be monitored for tumor formation.
- The FDA continues to describe the treatments' overall benefit-risk balance as favorable for their approved indications.
Not yet established
- The absolute lifetime chance of developing a tumor because of either gene therapy.
- Whether every reported tumor was caused by treatment, the best screening schedule or which groups may be at highest risk.
- Whether or when specific label updates or other regulatory actions will occur.
What should families understand about monitoring?
The FDA calls for monitoring for tumor formation, but its November 6 communication does not prescribe one universal MRI, blood-test or imaging schedule. Rather than arranging tests independently, families can request an individualized, documented follow-up plan from their neuromuscular or gene-therapy team. Ask whom to contact about new symptoms and how prior treatment and long-term study participation are recorded.
If someone develops a new concerning symptom, the care team can decide whether prompt examination or testing is needed. Decisions about therapy, imaging or medications should remain with the qualified treating team.
Follow-up questions for an SMA specialist
Use the Print control above or bring these into Appointment Prep.
- Which gene therapy did the person receive, on what date, and where is that treatment record kept?
- Has our team reviewed the November 6 FDA communication and its implications for this person's existing long-term monitoring plan?
- What changes or symptoms should prompt us to call your office, and whom do we contact outside normal hours?
- Are any assessments or follow-up studies recommended for this person, and why? What is not yet supported by evidence?
- Who coordinates follow-up among neurology, primary care and any other relevant specialists?
- How can we track new FDA safety updates or report a suspected adverse event appropriately?
Reporting and official sources
FDA asks healthcare providers to report tumors following treatment. The notice lists Novartis Gene Therapies: 1-833-828-3947 and FDA: 1-800-FDA-1088, including MedWatch online reporting ↗. Reporting can help regulators assess safety; a report does not by itself establish causation.
- FDA primary safety communication — November 6, 2026 ↗
- FDA Zolgensma product page and prescribing information ↗
- FDA Itvisma product page and prescribing information ↗
- Caregiver follow-up and practical support →
Editorial status: Prepared November 7, 2026 using the FDA's November 6 primary safety communication. Investigational safety risk, not a new medical screening guideline or instruction to alter care. Independent clinical review pending. Follow FDA for further regulatory updates.