BHVN Stock Crashes 10% – Why Did FDA Put Biohaven’s Epilepsy Trial On Partial Hold?

Biohaven said the FDA paused new patient enrollment in the BHV7000-303 trial after nonclinical studies in rodents identified a specific metabolite.

• FDA said it lacked enough information to assess whether the metabolite poses a risk to humans.
• Biohaven expects additional animal-study data addressing the FDA’s concerns in the coming weeks.
• Last month, Biohaven agreed to license its Kv7 platform, including Opakalim, to SK Biopharmaceuticals.

Shares of Biohaven (BHVN) sank around 10% in early trading on Thursday after the U.S. Food and Drug Administration placed a partial clinical hold on its experimental epilepsy drug over an unresolved finding from animal studies.

BHVN shares are on track to post their biggest single-day loss in more than 3 months.

FDA Requests Additional Metabolite Data

In an SEC filing on Thursday, Biohaven said the FDA paused new patient enrollment after nonclinical studies in rodents identified a specific metabolite, a substance produced when the body breaks down a drug. The regulator said it lacked enough information to assess whether the metabolite poses a risk to humans.

The biotech firm, which is testing Opakalim (BHV-7000), said the significance of the finding remains unclear and could be specific to rodents. More than 1,200 participants have already received BHV-7000 across its development program, with the drug generally showing a favorable safety and tolerability profile.

Biohaven expects additional animal study data to address the FDA’s concerns in the coming weeks. The trial is evaluating Opakalim in adults with refractory focal epilepsy.

What’s Next For BHVN?

Biohaven said patients already enrolled in the BHV-7000 program will continue to receive the drug while the company gathers additional animal study data on the metabolite. The BHV-7000 program contains two trials, BHV7000-302 and BHV7000-303.

The hold does not affect the timeline for BHV7000-303 because the study is already fully enrolled, with topline results still expected in the second half of 2026.

Dosing will also continue in BHV7000-302, but enrollment of new patients has been paused until additional data is issued.

$795M Deal In Focus

The development comes shortly after Biohaven agreed to license its Kv7 platform, including Opakalim, to SK Biopharmaceuticals. The agreement includes up to $795 million in upfront and milestone-related payments, along with royalties. Biohaven is set to receive $400 million in near-term cash consideration.

Biohaven said all clinical and nonclinical data related to the metabolite were disclosed to SK before the agreement was signed.

Retail Shrugs Off Concerns

Retail sentiment surrounding BHVN on Stocktwits remained ‘bearish’ over the past 24 hours.

One user said that if the metabolite were actively harming people, the FDA would have shut the whole program down immediately.

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Another user believes the stock is a minor hold.

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The stock has gained more than 16% so far in 2026.

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