Biohaven and SK Biopharmaceuticals signed a global licensing agreement worth up to $795 million for the Kv7 epilepsy platform led by opakalim. SK Biopharmaceuticals will pay $400 million upfront plus milestones and royalties, with RISE3 topline results expected in 2H 2026.
Biohaven and SK Biopharmaceuticals signed a $795 million global licensing deal for the Kv7 epilepsy platform led by opakalim, a selective Kv7.2/7.3 potassium channel activator in Phase 2/3 development for focal epilepsy.
"SK Biopharmaceuticals is an ideal partner having launched XCOPRI and is the only company to bring a new antiseizure medicine for partial-onset seizures to patients in the U.S. since 2016," Vlad Coric, chairman and CEO of Biohaven, said. "Pairing our scientific innovation with SK Biopharmaceuticals' established epilepsy development and commercialization expertise gives opakalim, if approved, its fastest and strongest path to patients worldwide."
SK Biopharmaceuticals will pay $400 million upfront — $350 million at closing and $50 million in 2027 — plus up to $150 million in development and regulatory milestones. Biohaven is eligible for tiered royalties ranging from mid-teens to low twenties on U.S. net sales of opakalim and mid-single digit royalties on ex-U.S. sales. SK Biopharmaceuticals will also assume up to $245 million in Knopp Biosciences and future Kv7 milestone obligations.
The deal delivers $400 million in non-dilutive capital to Biohaven while extending its cash runway to advance its broader pipeline across immunology, neuroscience, and oncology. Topline results from the RISE3 Phase 2/3 trial are expected in the second half of 2026, with the study evaluating opakalim at 50mg and 75mg once daily versus placebo in patients with refractory focal seizures.
Opakalim is designed to selectively activate Kv7.2/7.3 heteromeric potassium channels that regulate neuronal excitability, with substantially less activity at GABA receptors compared with earlier Kv7 activators. This selectivity profile is hypothesized to contribute to lower rates of somnolence, dizziness, and fatigue observed in clinical studies. The drug has been studied in more than 1,200 participants across multiple clinical trials, including two Phase 2/3 studies (NCT06132893 and NCT06309966) and an open-label extension study (NCT06443463).
In previously released open-label extension data, 54 percent of patients receiving opakalim 75mg once daily achieved a 50 percent or greater reduction in seizure frequency over a consecutive six-month period compared with baseline. The data was generated without a placebo control, so final efficacy and safety must be confirmed in the Phase 2/3 trials.
SK Biopharmaceuticals, through its U.S. subsidiary SK Life Science, markets XCOPRI (cenobamate) for partial-onset seizures in adults, with a neurology field force of more than 150 professionals. The company is the first Korean firm to independently discover, develop, and commercialize a novel antiseizure medicine.
The agreement also grants SK Biopharmaceuticals exclusive worldwide rights to Biohaven's other Kv7 activator compounds and the Kv7 Discovery Platform, enabling the company to discover follow-on drug candidates using the Kv7 mechanism. The deal term extends until the latest of 10 years post-launch, patent expiry, or regulatory exclusivity expiry.
Closing is contingent on completion of review under applicable regulatory and antitrust laws, including the Hart-Scott-Rodino Antitrust Improvements Act in the U.S. J.P. Morgan Securities served as exclusive financial advisor to Biohaven, with Sullivan & Cromwell as legal counsel. Nomura Securities International served as exclusive financial advisor to SK Biopharmaceuticals, with Paul Hastings as legal counsel.
The transaction gives Biohaven a strengthened balance sheet and a lower go-forward burn rate while preserving long-term upside through milestones and royalties. Investors will watch the RISE3 topline readout in the second half of 2026 as the next major event for the deal's value.
This article is for informational purposes only and does not constitute investment advice.
