Biohaven Faces Setback in Depression Treatment, Shifts Focus to Epilepsy

Biohaven Pharmaceuticals has encountered another significant obstacle in its drug development pipeline, as its potassium channel agonist BHV-7000 (opakalim) failed to demonstrate efficacy in a Phase II proof-of-concept study for major depressive disorder (MDD). This setback follows closely on the heels of a key FDA rejection in November 2025, painting a challenging picture for the company's psychiatric drug development efforts.

BHV-7000 Falls Short in Depression Trial

The Phase II study, which concluded on December 24, 2026, showed that BHV-7000 did not significantly improve depressive symptoms in MDD patients compared to placebo after six weeks of treatment. While Biohaven reported "trends" favoring the study drug, including improvements on primary and some secondary outcomes in patients with more severe depression at screening, these results were not sufficient to warrant further development in psychiatric indications.

Safety data from the trial revealed mild to moderate adverse events, primarily headache and nausea, with a low incidence of central nervous system side effects. This safety profile was consistent with previous studies and aligned with expectations given BHV-7000's lack of GABA activation.

Strategic Pivot and Industry Implications

In light of this failure, Biohaven has announced it will no longer pursue psychiatric indications for BHV-7000. This decision comes after a previous setback in a Phase II/III bipolar mania trial. The company will instead focus its efforts on developing the drug for two forms of epilepsy, with plans to provide a more comprehensive update on its strategy at the upcoming J.P. Morgan Healthcare Conference in San Francisco.

The news has implications beyond Biohaven, potentially benefiting competitors in the field. Analysts note that the failure removes an overhang for Xenon Pharmaceuticals, which is developing a similar potassium channel opener, XEN1101 (azetukalner). Xenon's asset has shown promising results in focal epilepsy, with Phase III data expected later this year.

Financial Pressures and Industry Response

Biohaven's recent setbacks have led to significant cost-cutting measures. In November 2025, following the FDA's rejection of its spinocerebellar ataxia treatment troriluzole, the company slashed its R&D budget by 60%. This latest failure adds to the pressure on Biohaven to maximize its resources and refocus its development pipeline.

Industry analysts have expressed mixed reactions to the news. William Blair described the trial results as disappointing but noted previous caution due to challenges in depression trials, including "clinical trial execution and placebo creep." Jefferies characterized the data as mixed but unsurprising. Stifel expressed skepticism about BHV-7000's ability to compete with Xenon's XEN1101 in focal epilepsy, given the high bar set by the latter's Phase IIb results, which showed a more than 50% reduction in seizures after eight weeks of treatment.