STAT+: FDA pauses Regenxbio gene therapy trial again due to safety concerns

The Food and Drug Administration has again paused trials for Regenxbio's gene therapy for a rare childhood brain disorder, mucopolysaccharidosis type II (Hunter syndrome), after small masses were found on the spines of five patients. Regenxbio said the patients had no symptoms related to the masses, according to the company's Monday announcement.

The pause comes seven months after Regenxbio reported that one boy who received a very similar therapy for MPS type I developed a brain tumor. That case was the first tumor to be conclusively linked to AAV gene therapy, the most commonly used form of gene therapy over the past two decades.

The new finding suggests ongoing safety concerns with AAV-based gene therapies and indicates regulators are closely scrutinizing Regenxbio's platform.