Cenobamate

A partial clinical hold on opakalim (BHV-7000), Biohaven Ltd.'s (NYSE: BHVN) selective Kv7.2/7.3 potassium channel activator in pivotal development for refractory focal epilepsy, arrives days after the New Haven-based company agreed to license the Kv7 platform to South Korea-based SK Biopharmaceuticals for up to USD 795 million, and with topline data from the pivotal BHV7000-303 study still expected in the second half of 2026. According to an 8-K filed with the SEC on September 9, 2026, the FDA issued a partial clinical hold letter on September 4, pausing new patient enrollment pending results of additional nonclinical studies characterizing a metabolite observed in rodent testing. Dosing continues for all patients already randomized across the program, more than 600 in total. BHV7000-303, one of two pivotal studies in refractory focal epilepsy, was fully enrolled and randomized before the hold was issued; its topline data timeline is unaffected. BHV7000-302, the companion pivotal study with an 8-week double-blind treatment period, continues dosing but cannot enroll new patients. The open-label extension study (BHV7000-201) also continues dosing. Biohaven said it voluntarily applied equivalent enrollment restrictions to its global sites outside the US. The metabolite in question was identified during routine nonclinical characterization. Biohaven said the significance of the findings in rodents to human safety is uncertain and may be species-specific. The company expects the additional nonclinical studies to generate clarifying data within weeks. All clinical and nonclinical data, including the metabolite findings, were disclosed to SK Biopharmaceuticals prior to signing the license agreement on August 26, 2026. Opakalim activates Kv7.2/7.3 heteromeric potassium channels, reducing neuronal excitability through the M-current — a mechanism distinct from GABA receptor modulation, which the company attributes to the drug's reported low rates of somnolence and dizziness in clinical studies. More than 1,200 participants have been dosed across the development program to date. Xenon Pharmaceuticals' (Nasdaq: XENE) azetukalner, also a Kv7.2/7.3 opener in Phase III for focal onset seizures, has reported positive topline data from its X-TOLE2 study and indicated plans to submit a new drug application to the FDA in Q3 2026. SK already has an existing US epilepsy infrastructure, built around its Xcopri (cenobamate) franchise. Biohaven said SK Biopharmaceuticals received all clinical and nonclinical data, including the metabolite findings, before signing the agreement. The companies continue to work toward closing, when USD 350 million becomes payable. Additional nonclinical results are expected in the coming weeks, but the timing of enrollment resumption remains uncertain. Spot something wrong? Report an issue with this article

SK Biopharmaceuticals has strengthened its epilepsy offering by paying $350 million upfront to help speed Biohaven’s Kv7 ion channel activator on its way to market. Biohaven is currently evaluating the daily oral therapy, called opakalim or BHV-7000, in a phase 2/3 study of patients with focal epilepsy. A topline readout is expected later this year. Rather than wait for the results, SK has agreed to hand over the upfront cash—along with another $50 million next year—for the worldwide license to both opakalim and Biohaven’s Kv7 platform. Beyond those near-term paydays, Biohaven will also be in line for up to $150 million in development and regulatory milestone payments, as well as a slice of the royalties should opakalim make it to market. Another element of the deal will see SK take on responsibility for certain milestone responsibilities that Biohaven owes the drug's original developer Knopp Biosciences in relation to the Kv7 platform. These obligations reach $245 million and mean that the total amount SK could eventually pay out in relation to this morning’s deal could reach $795 million. SK became an epilepsy player in its own right when it scored FDA approval for Xcopri in 2019 as a treatment for treat partial-onset seizures. The South Korean biopharma is hoping to launch opakalim in the U.S. as soon as 2029 via its U.S. subsidiary SK Life Science. SK’s CEO Donghoon Lee said the company’s experience with taking Xcopri from clinical development through to global rollout “has given us a deep understanding of what it takes to bring a differentiated CNS medicine to patients.” “We see opakalim as a highly complementary addition to our epilepsy portfolio, with a mechanism and tolerability profile that could extend our ability to serve patients who may benefit from additional treatment options,” Lee added. “We look forward to a close, collaborative partnership with the Biohaven team through NDA submission and beyond.” Biohaven CEO Vlad Coric, M.D., said that SK's “established epilepsy development and commercialization expertise gives opakalim, if approved, its fastest and strongest path to patients worldwide.” “Rather than stand up a commercial organization of our own for opakalim, we structured a partnership with a leading strategic partner in epilepsy to drive long-term revenue potential of this novel mechanism,” Coric explained. “This partnership also brings $400 million in near-term, non-dilutive capital to Biohaven while preserving substantial long-term upside for our shareholders.” Opakalim will be in a tough race with Xenon Pharmaceuticals’ own oral Kv7 ion channel activator azetukalner, which has already aced a phase 3 seizure trial earlier this year and is undergoing a late-stage study for generalized epilepsy. For its part, Biohaven has been touting opakalim’s ability to selectively activate the Kv7.2/7.3 heteromeric channels, while lacking GABA receptor activity, as “distinguishing it from other investigational Kv7 activators.” In this morning’s release, Coric explained that opakalim is designed to “deliver meaningful efficacy without the burdensome central nervous system side effects, including sedation and dizziness, associated with so many antiseizure medicines.” The Connecticut-based biopharma used its R&D Day in May to unveil an analysis from an open-label extension study of patients with ongoing focal epilepsy that showed that 54% of participants who received 75 mg of opakalim once daily achieved a 50% or greater reduction in seizure frequency over six months of treatment. The company also claimed at the time that the candidate had demonstrated “markedly lower incidence of nervous system adverse events” than other approved or investigational antiseizure medicines. The content above comes from the network. if any infringement, please contact us to modify.