So here's a fun little quirk of the stock market: sometimes your stock can go up because of good news about someone else's drug. That's what seems to be happening with Biohaven Ltd (BHVN) on Monday. The shares were trading higher in the premarket session, hitting as high as $12.52 before pulling back a bit.
The movement is a direct reaction to some positive data from a company called Xenon Pharmaceuticals Inc. (XENE). Xenon announced results from its Phase 3 X-TOLE2 study for a drug called azetukalner, which is being tested for focal onset seizures. The study met its primary endpoint, showing a placebo-adjusted median percentage change in monthly seizure frequency of -42.7% for the 25 mg dose group. That's a major drop, and it's good news for Xenon.
But why does that matter for Biohaven? Well, azetukalner is what's known as a KV7 potassium channel opener. It's a novel mechanism for treating epilepsy (and it's also in development for depression). Here's the connection: Biohaven is developing its own drug, called Opakalim (or BHV-7000), which is a selective activator of Kv7.2/7.3 potassium channels. It's essentially playing in the same biological sandbox. Opakalim is currently in two Phase 3 trials for focal and generalized epilepsy, and a Phase 2 study for major depressive disorder.
Think of it this way: Xenon just proved that the road to a particular destination—treating seizures by opening these specific potassium channels—can be successfully traveled. That de-risks, at least conceptually, the path for anyone else trying to go to the same place with a similar vehicle. Positive data for one drug in a class can often lift the prospects for others in development, because it validates the underlying science. Investors in Biohaven are betting that what works for Xenon's molecule might also work for Biohaven's.
Of course, it's not all smooth sailing for Biohaven's candidate. In December 2025, the company reported results from a Phase 2 proof-of-concept study evaluating BHV-7000 for major depressive disorder (MDD). That study did not meet its primary endpoint, which was a reduction of depressive symptoms as measured by a standard scale over six weeks compared with placebo. So, the drug's path in depression hit a speed bump, while its path in epilepsy just got a bit of a tailwind from a competitor.













