Clinical-stage biopharmaceutical company Biohaven Ltd (NYSE:BHVN) announced on Tuesday the completion of enrolment in RISE3, a pivotal Phase 2/3 randomised, double-blind, placebo-controlled study evaluating its selective Kv7.2/7.3 channel activator, opakalim, for the treatment of refractory focal epilepsy.

Top-line results from the study are expected in the second half of 2026.

RISE3 enrolled adult participants with refractory focal onset seizures who experienced at least four seizures per month and took one to three concurrent antiseizure medicines (ASMs), consistent with criteria used in other recent focal epilepsy ASM trials. Following an 8-week observation phase to establish baseline seizure frequency, participants were randomised (1:1:1) to one of two doses of opakalim (75 mg and 50 mg) or placebo once daily, as adjunctive therapy on a stable background regimen of ASMs, for an 8-week double-blind treatment period. The primary endpoint measures the change from baseline in 28-day average seizure frequency during the treatment phase. RISE2 is ongoing and has identical entry criteria and endpoints with a 12-week double-blind treatment period and evaluates opakalim 25 mg and 50 mg once-daily in Part A and 75 mg once-daily in Part B.

According to Biohaven, opakalim has been studied in more than 1,000 participants across multiple clinical trials, consistently demonstrating a favourable tolerability profile.