Biohaven Licenses Kv7 Epilepsy Platform to SK Biopharmaceuticals for up to $795M

Biohaven (NYSE: BHVN) is handing worldwide rights to its Kv7 ion channel platform and lead epilepsy candidate opakalim (BHV-7000) to South Korea’s SK Biopharmaceuticals in a deal worth up to $795 million. The transaction brings Biohaven roughly $400 million in near-term cash, leaves SK to fund and run development toward a hoped-for 2029 U.S. launch, and sent Biohaven shares up 18% to $16.95 on 15.8 million shares traded, well above the stock’s typical volume.

The headline number breaks down fast, as this guide to licensing-deal economics explains. Biohaven receives $350 million upfront at closing, another $50 million in 2027, and up to $150 million in development and regulatory milestones, plus tiered royalties of mid-teens to low-20s on U.S. net sales of opakalim. SK also assumes $245 million of Biohaven’s existing obligations: up to $185 million payable to Knopp Biosciences upon U.S. and EU approval, and up to $60 million tied to future Kv7 pipeline programs.

Opakalim is a selective Kv7.2/7.3 potassium channel activator, an oral once-daily pill designed to calm overactive neurons without the sedation and dizziness that weigh on older antiseizure drugs. Kv7 channels act as the brain’s natural brake on firing; opening them quiets overactive neurons. The pitch is that selective Kv7.2/7.3 activation, with no GABA activity, delivers seizure control with fewer cognitive side effects. Epilepsy affects roughly 3 million U.S. adults, and up to half of people with focal seizures still lack adequate control on existing drugs, which is why a tolerability-first option matters.

Biohaven keeps running the ongoing Phase 2/3 trials, while SK covers development costs from here. Topline results from the RISE3 trial are expected in the second half of 2026, and SK’s Korean regulatory filing points to a 2029 U.S. launch.

The bet is a crowded one. Xenon Pharmaceuticals’ azetukalner, another Kv7 opener, reported positive Phase 3 X-TOLE2 data in March showing a 53.2% reduction in monthly focal seizures versus 10.4% for placebo, and Xenon is targeting an FDA filing this year. Opakalim would arrive into a market where a Kv7 competitor may already be entrenched, and it is a year or more behind.

The risk for Biohaven shareholders is what the company gave up: it keeps royalties and milestones, but SK owns the commercialization upside it once intended to build itself. Watch the RISE3 readout in the second half of 2026. If opakalim’s tolerability holds up against azetukalner’s already-strong data, SK’s Xcopri sales force gets a genuine second act.

Source: Biohaven and SK Biopharmaceuticals press release