FDA hands Biohaven refusal to file letter for brain disorder drug

July 27, 2023

The U.S. FDA will not review Biohaven's recently submitted NDA application for troriluzole, a prodrug designed to treat a rare brain disorder, citing a failed phase 3 study.

Connecticut-based Biohaven shared the news within a corporate update, noting the company's plans to request a Type A meeting with the agency to "comprehensively address FDA's concerns cited in the refusal to file letter."

Back in May, Biohaven submitted troriluzole to the FDA for the treatment of spinocerebellar ataxia type 3 (SCA3), an ultra-rare, genetically-defined, neurodegenerative disease associated with progressive disability, frequent falls, loss of ambulation, speech and swallowing impairment, and premature death.

But the application relied on a phase 3 study, BHV4157-206, which had failed to meet its primary endpoint last year. Both the placebo and the troriluzole group showed minimal change on the Scale for the Assessment and Rating of Ataxia — an eight-point performance scale that measures impairment levels — at the 48-week endpoint. However, the drug did lead to a reduction of falls in the troriluzole group.

It wasn't enough to convince the FDA, but Biohaven hasn't given up.

"We believe the NDA package is compelling and shows that treatment with troriluzole leads to clinically meaningful treatment benefits, including significantly delaying disease progression and reduction in falls. We stand by these data and analyses," said Vlad Coric, Biohaven CEO and chairman.