Ultragenyx Forced To Cut Costs After Disappointing Phase 3 Results

Ultragenyx Pharmaceutical Inc. (NASDAQ:RARE) stock is tumbling on Thursday after reporting late-stage clinical trial failures for its Angelman syndrome therapy, apazunersen, prompting the biopharmaceutical firm to review the program’s future and plan significant corporate expense reductions.

Understanding Apazunersen And Angelman Syndrome

Apazunersen is an investigational intrathecal antisense oligonucleotide therapy designed to inhibit UBE3A-AS expression.

Angelman syndrome is a rare neurogenetic disorder caused by loss-of-function in the maternally inherited UBE3A gene allele. The condition causes cognitive and motor impairments, balance issues, and seizures.

Phase 3 Trial Fails Primary And Secondary Endpoints

The company’s Phase 3 Aspire study evaluated apazunersen, also designated as GTX-102, in patients with Angelman syndrome.

Data showed that the trial missed its primary endpoint, which measured the change from baseline in the Bayley-4 cognitive raw score.

The Bayley-4 measures developmental functioning and potential delays in infants and toddlers from 16 days to 42 months old. 

The drug also failed its key secondary endpoint of net response on the Multidomain Responder Index, an analysis tool to capture a broader assessment of clinical benefit.

Randomized treatment groups remained comparable at baseline, mirroring patient demographics from Phase 2 trials.

However, comparisons between treated and control groups revealed no efficacy differences in Bayley Cognition raw scores or net response across the five individual endpoints included in the responder index.

Apazunersen maintained a safety profile consistent with earlier Phase 1/2 testing.

Corporate Restructuring And Strategic Review

Following the trial results, management plans to evaluate the apazunersen program to determine its ultimate disposition.

Ultragenyx will also assess operations to implement significant expense reductions while supporting its growing commercial business.

RARE Price Action: Ultragenyx Pharmaceutical shares were down 47.57% at $13.91 during premarket trading on Thursday. The stock is trading at a new 52-week low, according to Benzinga Pro data.

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