SK Chemicals Co. Ltd.

Just two weeks after Biohaven moved to out-license its lead epilepsy candidate, a late-stage trial of opakalim (BHV-7000) has hit a stumbling block.The drugmaker disclosed in a securities filing Thursday that the FDA has placed a partial clinical hold on the Phase II/III BHV7000-302 trial evaluating the selective Kv7.2/7.3 potassium channel activator in patients with refractory focal onset epilepsy. The hold was triggered after certain metabolites of opakalim were observed in rodent testing. Although Biohaven gave global regulators an update about the nonclinical characterisation findings, "it was determined that there was insufficient information related to a specific metabolite to assess risks of that metabolite to human subjects at this time." Under the hold, new patient enrollment is paused "pending nonclinical data that is expected in the coming weeks to further elucidate findings related to this metabolite that have uncertain significance in humans," though already randomised participants can continue to receive treatment. "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," Biohaven emphasised, adding that to-date, over 1200 individuals have received opakalim, which has "generally been safe and well-tolerated."Because its second Phase II/III trial of opakalim, RISE3, has already finished enrollment, dosing will continue unaffected, and the study is still on track to report topline data this half. Dosing in the BHV7000-201 open-label extension study will also remain ongoing. Deal hangs in the balance The hold was placed while Biohaven is working to close a licensing deal handing SK Biopharmaceuticals exclusive, worldwide rights to its Kv7 ion channel platform.Under the proposed deal, SK Bio agreed to pay $350 million upfront plus a $50-million payment next year, as well as up to $150 million in milestones. Biohaven stands to receive tiered royalties as well, ranging from mid-teens to low-twenties on US sales, and a mid-single-digit percentage on ex-US sales. If finalised, the partners will jointly advance opakalim towards FDA approval in epilepsy.

SK Biopharmaceuticals signed a licensing and collaboration agreement, potentially worth $795 million, for exclusive rights to Biohaven's Kv7 ion channel platform, headlined by the lead asset opakalim (BHV-7000).Opakalim — a selective Kv7.2/7.3 potassium channel activator — is currently being investigated across two Phase II/III trials in refractory focal onset epilepsy, with top-line readout from the RISE3 study expected later this year. The once-daily oral treatment requires no titration and carries a low incidence of onerous central nervous system side effects.Highlighting the company's "experience building Xcopri [cenobamate] into a therapy for epilepsy patients worldwide," SK Biopharm CEO Donghoon Lee said opakalim represents "a highly complementary addition to our epilepsy portfolio."Under terms of the deal announced Wednesday, the partners will jointly advance opakalim towards FDA approval in epilepsy. SK Biopharm will pay Biohaven $400 million in near-term cash, including $350 million at closing and $50 million next year, with the latter also eligible for milestone payments of up to $150 million. Furthermore, Biohaven stands to receive tiered royalties ranging from the mid-teens to low twenties on US sales, and a mid-single-digit on ex-US sales. SK Biopharm will also assume additional Kv7 programme costs, including up to $185 million in Knopp Biosciences obligations and up to $60 million tied to future Kv7 pipeline milestones.For opakalim, however, things have not been rosy on the psychiatric front. The drug missed the primary endpoint in a Phase II major depressive disorder (MDD) study last December after earlier falling short in a late-stage bipolar mania trial. Following the MDD setback, Biohaven said it would not plan additional trials in psychiatry and instead redirect efforts towards immunology, obesity and epilepsy programmes.Biohaven has also faced financial pressure since the FDA turned down its spinocerebellar ataxia hopeful Vyglxia (troriluzole) last year, prompting R&D cuts and a pipeline realignment. The latest deal could provide the company with a much-needed boost by strengthening its balance sheet and reducing future spending, freeing up resources for its broader pipeline.

Taylor Tieden for BioSpace At the center of Biohaven’s agreement with SK Biopharmaceutical is the ion channel platform and the lead epilepsy candidate opakalim, for which Phase 2/3 data are expected later this year. Biohaven is licensing out its Kv7 platform and lead epilepsy asset to Seoul-based SK Biopharmaceutical in a deal that could rack up nearly $800 million in payments. Under the terms of the agreement, announced Wednesday , Biohaven is looking at $400 million in a near-term cash infusion, including a $350 million tranche payable at closing and $50 million payable next year. Meanwhile, development and regulatory milestones could hit up to $150 million. On top of these considerations, SK Bio has agreed to assume up to $185 million of Biohaven’s milestone obligations under a February 2022 agreement with Knopp Biosciences, through which Biohaven gained the ion channel platform. The South Korean developer has also agreed to take over up to $60 million in milestone payments related to the technology. All told, the Wednesday deal could reach up to $795 million in total value, money that would beef up Biohaven’s cash position. As of June 30, the company had $270.5 million in cash, equivalents, marketable securities and restricted cash. In return for its investment, SK Bio will receive an exclusive global license to Biohaven’s Kv7 ion channel platform and the lead epilepsy asset opakalim, an oral daily selective potassium channel activator that is currently in development for focal epilepsy. The Phase 2/3 RISE3 trial for opakalim is ongoing, with topline data expected in the back half of 2026, according to the Wednesday announcement. The deal comes as Biohaven enters what William Blair analysts in an Aug. 11 note called a “catalyst-rich period”—one that is “not without risk but is potentially transformative.” One of these catalysts is the RISE3 readout, which is a main focus for investors, according to the firm. Aside from RISE3, Biohaven is also anticipating mid-stage data for taldefgrobep alfa before the year ends. The molecule is an investigational myostatin and activin receptor blocker being studied for obesity. Biohaven had previously been developing taldefgrobep alfa for spinal muscular atrophy but pivoted development plans after a late-stage stumble in November 2024. Biohaven is positioning taldefgrobep alfa as a muscle-preserving weight loss therapy. “Blocking myostatin signaling optimizes skeletal muscle growth,” Peter Ackerman, senior vice president of clinical development at Biohaven, told BioSpace ahead of the American Diabetes Association meeting in June. “We believe that we can bring higher quality of weight loss.” Obesity Biohaven looks to obesity to bounce back from run of clinical and regulatory failures After trial flops in spinal muscular atrophy, depression and bipolar disorder—and a costly rare disease drug rejection—Biohaven is undergoing a reset, recasting its former SMA candidate for obesity. June 1, 2026 · 5 min read · Heather McKenzie Read more