Biohaven collaborates with SK Pharmaceuticals on Opakalim to treat focal epilepsy
Biohaven is currently evaluating the therapy in the Phase II/III RISE3 study, with results expected in the second half of 2026.
USA—Biohaven and SK Pharmaceuticals have entered a licensing and partnership agreement to advance opakalim, an investigational epilepsy therapy that could become one of the first potassium channel openers to reach the market.
Under the agreement, SK will acquire global rights to Biohaven’s Kv7 ion channel platform, including opakalim, in a deal worth up to US$795 million in upfront and milestone payments.
Biohaven will also be eligible for tiered royalties on US sales ranging from the mid-teens to the low twenties.
SK to fund Kv7 development
SK will assume the costs of advancing the Kv7 platform and has committed up to US$245 million to cover third-party and future platform expenses.
Kv7 channels are voltage-gated potassium channels that help regulate electrical activity and cell excitability in the nervous system, heart and muscles.
Opakalim selectively activates the Kv7.2/7.3 channels and is being developed as a potential treatment for focal epilepsy.
Biohaven is currently evaluating the therapy in the Phase II/III RISE3 study, with results expected in the second half of 2026.
If successful, the programme could support the drug’s progression into late-stage development and potentially toward regulatory approval.
Race to develop Kv7 epilepsy therapies
The partnership brings SK, which developed the approved anti-seizure medicine Xcopri (cenobamate), into competition with Xenon Pharmaceuticals and its Kv7.2/7.3 opener azetukalner.
Azetukalner could have a first-to-market advantage.
Xenon plans to submit a New Drug Application (NDA) to US regulators in the third quarter of 2026 after the therapy delivered positive Phase III results.
Meanwhile, Biohaven must first await the RISE3 results for opakalim.
Neither opakalim nor azetukalner has yet secured regulatory approval, and no potassium channel opener is currently approved for epilepsy.
Opakalim’s Safety profile under scrutiny
To date, opakalim has demonstrated fewer central nervous system side effects than azetukalner in clinical development.
Patients receiving opakalim have reported lower rates of dizziness, sedation and fatigue.
However, Leerink analysts have raised questions about whether the drug’s apparently cleaner safety profile could reflect weaker target engagement rather than greater selectivity.
This uncertainty has prompted questions about whether opakalim can deliver efficacy comparable with azetukalner.
Both therapies are targeting focal epilepsy, a form of epilepsy in which seizures originate in a specific area of the brain.
Growing epilepsy market
If approved, either therapy would enter a market that GlobalData estimates will be worth US$17.8 billion in 2035 across the seven major markets: the US, France, Germany, Italy, Spain, the UK, and Japan.
GlobalData has also identified opakalim as one of 12 late-stage pipeline products that could influence the future growth of the epilepsy market.
Be the first to leave a comment