FDA Rejects Biohaven’s Ataxia Drug Vyglxia, Forcing Company to Cut Costs After Second Approval Failure

The FDA rejected Biohaven's application for Vyglxia (troriluzole) for treating spinocerebellar ataxia (SCA), a rare, progressive neurodegenerative disease that impairs coordination and muscle control1 4 7.

This marks Biohaven's second failed attempt to gain FDA approval for a treatment targeting ataxia1 2.

The agency's Complete Response Letter (CRL) cited concerns about the use of external historical controls in the main clinical study, raising issues of potential bias, confounding variables, and questionable data analysis methods1 4 5.

Although Biohaven's study showed Vyglxia appeared to slow disease progression by 50–70%, and reduced fall risk by over 50%, the FDA did not accept real-world evidence as adequate, stating a more robust, less-biased design was needed to demonstrate effectiveness1 4.

The application included a large, three-year study tracking over 900 patients with SCA, but lacked a traditional placebo group1 4.

Vyglxia had previously received Orphan and Fast Track designations from the FDA due to the lack of approved treatments for SCA6.

Biohaven will cut R&D expenses by approximately 60% and restructure business operations following the rejection, as their stock price dropped by more than 40% after the news1 4 6 8.

The company plans to urgently meet with the FDA to address outstanding concerns and discuss the future of their ataxia program, emphasizing the unmet medical need in SCA1 4.