Biohaven's pivotal epilepsy trial for opakalim heads toward H2 2026 readout
The first of two registrational studies testing the Kv7.2/7.3 activator against placebo in drug-resistant focal epilepsy is set to post results, building on tolerability data Biohaven says separates it from rival Kv7 activators.
Executive Summary
- Biohaven is heading toward the first placebo-controlled pivotal readout for opakalim in drug-resistant focal epilepsy, a result that will test whether seizure-reduction signals seen in earlier open-label and proof-of-concept data hold up under randomization.
- The trial is registrational, meaning the result feeds directly into Biohaven's regulatory plans for the drug in this indication rather than serving as an exploratory signal.
- Opakalim's differentiation case rests on tolerability rather than a novel target category: it activates the same Kv7.2/7.3 channels as an already-competing investigational activator but is positioned around avoiding the central nervous system side effects that have limited that class.
- The trial's primary completion date has already moved by more than a year, and the readout's operational credibility depends on execution catching up to the sponsor's public guidance.
The catalyst
Biohaven said it expects topline data in the second half of 2026 from NCT06132893, the first of two randomized, double-blind, placebo-controlled Phase 2/3 studies of opakalim (BHV-7000) supporting registration in refractory focal epilepsy. The trial is testing whether opakalim reduces 28-day average seizure frequency against placebo in adults 18 to 75 who have failed at least two prior antiseizure medication regimens, one of four co-primary endpoints registered alongside safety measures covering serious adverse events and clinically significant lab abnormalities. The study is enrolling toward a target of 390 participants across ten countries including the United States, Poland and France. Biohaven+1Biohaven Reports New Clinical Data in Epilepsy with Opakalim, a Selective Kv7.2/7.3 Activator, Highlighting Seizure Control and Markedly Differentiated Tolerability ProfileMay 26, 2026A Study to Determine if BHV-7000 is Effective and Safe in Adults With Refractory Focal Onset EpilepsyNCT06132893
Probability of SuccessBased on the AppliedXL Probability of Success model. For more information about the methodology, read the research here.
Building on open-label data
Biohaven has already disclosed supporting clinical data ahead of this pivotal readout. In a separate randomized, placebo-controlled trial in idiopathic generalized epilepsy, the median time to a second generalized tonic-clonic seizure was 141 days on opakalim 75 mg once-daily versus 47 days on placebo, a three-fold prolongation. In an ongoing open-label extension in focal epilepsy, 54% of patients on opakalim 75 mg achieved at least a 50% reduction in seizure frequency over any six consecutive months of treatment compared with their pre-randomization baseline. Biohaven also reported that opakalim's tolerability profile showed central nervous system adverse event rates at or below 5% in the focal epilepsy extension study, which it says compares favorably with other investigational Kv7 activators reporting double-digit rates of similar side effects. Jason Lerner, Biohaven's Medical Director for epilepsy development, said the data "across IGE, focal epilepsy and KCNQ2-DEE are consistent and compelling," adding that "what stands out is not just that opakalim controls seizures, it's that it does so without the burdensome side effects that compromise quality of life and adherence for people with epilepsy". BiohavenBiohaven Reports New Clinical Data in Epilepsy with Opakalim, a Selective Kv7.2/7.3 Activator, Highlighting Seizure Control and Markedly Differentiated Tolerability ProfileMay 26, 2026
Timing and protocol history
The trial's primary completion date shifted from August 1, 2025 to December 1, 2026, a change recorded in the trial's registry history in October 2025. The study's eligibility criteria have been modified four times and its start date changed three times since the trial was first posted in November 2023. Enrollment has stayed unchanged at 390 participants, a routine signal under the operational model's threshold for flagging enrollment shifts. Independent forecasting places the readout's point estimate around September 4, 2026, with a range extending from August 20 to December 7, 2026, consistent with the sponsor's stated second-half 2026 window. NCT06132893A Study to Determine if BHV-7000 is Effective and Safe in Adults With Refractory Focal Onset EpilepsyNCT06132893
The competitive frame
No trial in the indication-matched competitive landscape shares opakalim's Kv7.2/7.3 target and its stated lack of GABA receptor activity; the nearest mechanism neighbor identified is Xenon Pharmaceuticals' azetukalner, a Kv7 modulator in Phase 3 testing for epilepsy that operates through a different binding profile. Other named programs in the broader focal and generalized epilepsy field, including UCB's brivaracetam and alprazolam programs and Immedica's ganaxolone in CDKL5 deficiency disorder, work through SV2A, GABAA and GABA-A mechanisms respectively, making them contextual rather than direct comparators. With no validated Kv7.2/7.3-selective therapy yet established in this population, a placebo-controlled result showing seizure-frequency reduction that persists alongside a differentiated tolerability profile would be the finding that most clearly extends opakalim's open-label signal into decision-grade evidence.
This analysis was produced using AI-assisted reporting systems, AppliedXL data, and official public records. These systems undergo editorial review, quality checks, and regular audits by human experts. Errors may still occur, as with any automated system. Always consult the linked primary sources. Read our AI Editorial Policy.