FDA issues partial hold on Biohaven’s experimental epilepsy drug opakalim, pausing recruitment in late-stage trial

Biohaven announced that the FDA has placed a partial hold on its experimental epilepsy therapy, opakalim, after the company recently transferred rights to the drug in a licensing agreement.

The agency asked for additional data on a metabolite observed in rodent studies, requiring the company to stop enrolling new patients in the ongoing late-stage RISE-2 trial, though dosing will continue for participants already enrolled.

The hold does not affect the separate RISE-3 trial, which remains fully enrolled and is expected to deliver results later this year, a key milestone for Biohaven.

Analysts note that if opakalim eventually receives approval, Biohaven stands to receive milestone payments and royalties from its partner SK Pharmaceuticals, but the current regulatory action caused the stock to drop more than 10% on the news.