The enrollment pause comes after BHV-7000 failed to show efficacy in a midstage depression trial late last year. The news is another regulatory hit for Biohaven after the FDA declined to approve its spinocerebellar ataxia treatment in November 2025.
Biohaven stock fell more than 13% in premarket trading Thursday as the FDA slapped a partial clinical hold on its Kv7 potassium channel agonist in focal epilepsy. This latest development comes days after SK Biopharmaceuticals snagged a worldwide license to the Kv7 platform, including the epilepsy candidate.
It’s also the second regulatory blow to Biohaven in a year. Last November, the FDA turned away the biotech’s spinocerebellar ataxia treatment troriluzole, causing the company to slash its R&D budget by 60%. Biohaven’s shares dropped by nearly 45% at the time and have yet to fully recover.
The partial hold on BHV-7000, which is also known as opakalim, pertains to the enrollment of new patients in two late-stage focal epilepsy studies. It was placed so the FDA could assess potential risk to humans from a metabolite identified during rodent testing, according to a Thursday SEC filing from Biohaven. The agency is requesting that Biohaven complete additional nonclinical research for more information.
Dosing will continue for all patients already randomized in the two pivotal trials—RISE 2 and RISE 3—which together comprise more than 600 participants.
Enrollment in RISE 3 was completed in June, Biohaven said in the same filing, and a topline data readout remains on track for the second half of this year. RISE 2, however, had not yet completed recruitment. The enrollment pause “is likely to delay the readout of this trial, which will also likely will need to read out positively for regulatory approval,” RBC Capital Markets said in a note to investors Thursday morning. RISE 2 was previously expected to have a primary completion date in December this year.
“The significance of the nonclinical metabolite findings to humans is uncertain,” Biohaven said in the filing. “The findings may be specific to rodents and not relevant to human safety, and the additional nonclinical studies underway are intended to address that question. BHV-7000 has generally been safe and well-tolerated in clinical
studies with over 1,200 participants dosed to date.”
RBC analysts also pointed to this comprehensive safety profile, writing: “If the partial clinical hold is not lifted or nonclinical data is not able to definitively demonstrate that the metabolite does not pose any risk to humans, we believe that BHVN may still be able to potentially rely upon the wealth of human data that they have to reassure regulators that ‘7000 may not pose greater risk to humans.”
This partial pause is not the first trouble Biohaven has encountered with the Kv7 asset. In December 2025, BHV-7000 failed to improve symptoms in patients with major depressive disorder after six weeks as compared to placebo during a Phase 2 proof-of-concept study.
BHV-7000 is the lead asset from Biohaven’s Kv7 platform. The asset is a “potent, selective activator of Kv7.2/7.3 potassium channels,” a clinically validated target to regulate the hyperexcitable state in epilepsy, according to the company’s website. “Increasing evidence also suggests the potential for Kv7.2/7.3 activators to treat neuropsychiatric and pain disorders.”
On Aug. 26, Biohaven Bioscience Ireland Limited signed a worldwide licensing agreement worth up to $795 million with SK Biopharmaceuticals for Biohaven’s Kv7 ion channel platform, including BHV-7000 as well as other Kv7 compounds and products covered by the agreement. “All clinical and nonclinical data, including those related to the metabolite characterization submitted to global regulatory authorities, was fully disclosed to SKBP prior to the signing of the License Agreement,” according to the SEC filing.
