Ultragenyx gene therapy for Angelman syndrome fails Phase 3 trial, company to cut expenses

An experimental gene therapy targeting Angelman syndrome did not meet its primary endpoint in a Phase 3 study, according to Ultragenyx. The trial showed no difference between the therapy, GTX-102, and a sham procedure.

Angelman syndrome is a rare neurodevelopmental disorder that causes severe intellectual disability and developmental delays. Earlier Phase 1 and 2 studies of GTX-102 had generated optimism among families and researchers.

The negative result is a setback for Ultragenyx’s pipeline and financial outlook. The company said it will implement significant expense reductions in response to the outcome.