The Ultragenyx Angelman trial failed to meet its main efficacy goals, creating a significant setback for the company’s apazunersen development program.
Ultragenyx Pharmaceutical (Nasdaq: RARE) said in its official Phase 3 announcement that the Aspire study did not achieve its primary endpoint, which measured change from baseline in the Bayley-4 cognitive raw score.
The study also missed its key secondary endpoint based on the net response in the Multidomain Responder Index. Ultragenyx said the safety profile observed in Aspire was consistent with the earlier Phase 1/2 program, but the lack of efficacy on the principal measures limits the value of that safety finding for the program’s regulatory path.
Ultragenyx Angelman Trial Failure Forces a Strategic Review
Apazunersen, previously known as GTX-102, is an investigational therapy designed for Angelman syndrome, a rare neurodevelopmental disorder. Aspire evaluated the treatment in children with a genetically confirmed deletion affecting the maternal UBE3A gene.
The company said it would evaluate the apazunersen program following the results and decide how to proceed. It also plans to review its operations and implement significant expense reductions while continuing to support its commercial portfolio.
The failed trial removes a potential near-term development catalyst and raises questions about related studies and future spending on the program. Any decision to discontinue, redesign or continue development will depend on a fuller analysis of the Aspire data and discussions with regulators; the initial announcement does not establish the final disposition of apazunersen.
