Biohaven Plummets, A Boon For Rival Xenon, On A Surprise Seizure Setback

Biohaven (BHVN) stock plummeted Thursday after the company paused enrollment in a midstage study of its seizure treatment due to safety concerns. The Food and Drug Administration is now requiring Biohaven to assess the potential for human toxicity from a metabolite in the drug, opakalim. Opakalim is in testing as a treatment for focal onset seizures. But, in rats, it…