Science Report Links AAV9 Gene Therapy to Brain Tumor 4 Years Later
Updated
Updated · exaudi.org · May 18
Science Report Links AAV9 Gene Therapy to Brain Tumor 4 Years Later
5 articles · Updated · exaudi.org · May 18
Four years after experimental AAV9 gene therapy for Hurler syndrome, a child developed a neuroepithelial brain tumor, sharpening scrutiny of long-term safety in viral-vector treatments.
Genetic analysis found fragments of the vector integrated into tumor-cell DNA near the PLAG1 oncogene, along with a hybrid transcript that points to a plausible cancer-causing mechanism.
AAV vectors had been viewed as relatively safe because they usually remain outside the genome; researchers said this appears to be a rare event, not a broad indictment of gene therapy.
The tumor was surgically removed and the patient remains alive with good quality of life, underscoring the risk-benefit tradeoff in treating otherwise fatal diseases.
The case revives earlier gene-therapy safety failures and strengthens calls for years-long monitoring, tighter informed consent and development of lower-integration or non-viral approaches.
Gene therapy can cure fatal diseases but also cause cancer. Can science now predict and prevent these devastating genetic accidents?
With public oversight shrinking, who will guard patients against the newly discovered dangers of revolutionary gene therapies?
Rare Brain Tumor in Child After AAV Gene Therapy Triggers FDA Holds and Sparks Safety Debate
Overview
In early 2026, a rare complication emerged when a brain tumor was discovered in a five-year-old child four years after receiving RGX-111 gene therapy. This led the FDA to halt both the RGX-111 and RGX-121 trials on January 28, 2026, to investigate a possible link between the therapy and tumor development. Although the child remained asymptomatic, the incident raised concerns about the long-term safety of adeno-associated virus (AAV) gene therapies. The case prompted industry-wide scrutiny, highlighting the need for ongoing monitoring and more rigorous safety assessments in future gene therapy trials.