Biohaven gets $400m near-term cash as SK Biopharmaceuticals takes opakalim rights

Biohaven Ltd. (NYSE: BHVN) has struck one of the more consequential late-stage biotechnology licensing deals of 2026, giving SK Biopharmaceuticals Co., Ltd. exclusive global rights to opakalim and Biohaven’s broader Kv7 ion-channel platform for up to $795 million in upfront and development-related consideration before royalties. The structure includes $350 million in cash at closing, another $50 million one year later and as much as $395 million in development and regulatory milestones, while Biohaven retains tiered royalties ranging from the mid-teens to low twenties on U.S. opakalim net sales plus additional royalties on ex-U.S. sales and certain future Kv7 products. The timing is unusual because pivotal Phase 2/3 RISE3 data in refractory focal epilepsy are expected before the end of 2026, meaning Biohaven is transferring commercial control shortly before a clinical readout that could substantially change the asset’s value. In exchange, the company eliminates the need to construct an expensive epilepsy commercialization operation and receives non-dilutive capital that exceeds its June cash balance even before potential milestones are considered.

SK Biopharmaceuticals is not buying an isolated molecule. The agreement includes exclusive worldwide development and commercialization rights to opakalim together with access to Biohaven’s Kv7 discovery platform and related compounds generated from it. SK intends to use its existing U.S. epilepsy infrastructure around XCOPRI and has identified a potential U.S. opakalim launch as early as 2029 if development and regulatory milestones proceed as planned.

How much money is actually guaranteed in the $795 million Biohaven deal?

The headline transaction value requires careful separation. SK Biopharmaceuticals has committed $400 million in upfront cash consideration, with $350 million payable when the transaction closes and another $50 million payable one year afterward. A further $395 million is tied to development and regulatory milestones, meaning it will be paid only if specified future events are achieved. Royalties sit outside the $795 million headline amount.

SK disclosed that as much as $335 million of the milestone pool relates directly to opakalim, while approximately $60 million relates to other compounds generated through the Kv7 platform. A portion of milestone and royalty payments is also owed to Knopp Biosciences, the original developer associated with the technology. Closing remains subject to required antitrust clearances and customary conditions, so the $350 million initial payment should not be treated as cash already received by Biohaven.

The near-term financing effect is nevertheless substantial. Biohaven held approximately $270.5 million of cash, cash equivalents, marketable securities and restricted cash at June 30. The $400 million near-term package would therefore equal roughly 1.5 times that quarter-end liquidity before considering future milestones, materially extending a balance sheet supporting several concurrent clinical programs.

Why is SK Biopharmaceuticals willing to license opakalim before Phase 3 data?

Opakalim, previously known as BHV-7000, selectively activates Kv7.2/7.3 potassium channels that help regulate neuronal excitability. Biohaven has designed the drug as a once-daily oral antiseizure therapy without titration and with limited activity at GABA receptors, seeking to reduce adverse effects such as dizziness, somnolence, fatigue and cognitive impairment that can limit adherence to existing epilepsy medicines. More than 1,200 participants have received opakalim across clinical studies to date.

The clinical evidence is promising but not yet registrationally decisive. Biohaven reported that 54% of participants receiving 75 mg once-daily opakalim in an ongoing focal-epilepsy open-label extension achieved at least a 50% reduction in seizure frequency over a consecutive six-month period relative to their pre-randomization baseline. Dizziness occurred in approximately 5% and fatigue in about 4% in the analysis, supporting the company’s argument that tolerability could become a differentiator. Open-label extension findings, however, do not carry the evidentiary weight of randomized pivotal data.

RISE3 is therefore the near-term test. The randomized study enrolled adults experiencing at least four refractory focal seizures per month despite using one to three concurrent antiseizure medicines. Participants receive 50 mg or 75 mg of opakalim or placebo once daily after an eight-week baseline observation period, with the primary endpoint measuring change in average 28-day seizure frequency. A second pivotal study, RISE2, is also underway.

Why does SK Biopharmaceuticals have a strategic advantage as the commercial partner?

SK already operates a dedicated U.S. epilepsy business through SK Life Science and has built a neurology field force of more than 150 professionals around XCOPRI, or cenobamate. The company describes XCOPRI as the leading branded newer epilepsy medicine in the U.S. market and sees opakalim as a potential second directly commercialized innovative product. Instead of recreating that infrastructure, Biohaven can effectively rent SK’s existing neurologist relationships through royalties and milestone economics.

The portfolio logic is also notable because XCOPRI and opakalim are mechanistically differentiated rather than direct duplicates. SK can potentially approach the same epilepsy centers with complementary medicines while using one field force, medical-affairs operation and payer infrastructure. That creates commercial efficiencies that a standalone Biohaven launch would have struggled to match without substantial fixed investment.

SK is taking on meaningful clinical risk by signing before RISE3 results, but that timing also prevents Biohaven from demanding materially higher economics after a successful pivotal readout. The transaction can therefore be interpreted as a negotiated division of risk: SK accepts late-stage uncertainty in exchange for global ownership, while Biohaven secures substantial cash and retains royalties without funding a global commercial build-out.

Does Biohaven still retain enough upside after giving away global rights?

Biohaven is surrendering direct commercial ownership of what could become a significant epilepsy product, but the retained royalty structure is unusually meaningful. Mid-teens to low-twenties royalties on U.S. sales can create substantial high-margin revenue if opakalim becomes a major medicine, while additional ex-U.S. royalties and milestone payments preserve upside without requiring Biohaven to finance sales infrastructure.

The more immediate benefit is portfolio flexibility. Biohaven is simultaneously advancing extracellular protein degraders, immunology programs, oncology candidates and other neurological assets. The company started the third quarter with only about $270.5 million of liquidity, so funding an independent opakalim launch while maintaining those programs could have forced significant capital allocation trade-offs or additional equity financing. The SK transaction transfers future Kv7 program costs to a partner while freeing Biohaven capital for the rest of its pipeline.

That trade-off becomes most visible if RISE3 succeeds spectacularly. Biohaven shareholders would benefit through milestones and royalties but would no longer own the full commercial margin of the asset. If RISE3 disappoints, however, securing hundreds of millions of dollars before the readout will look considerably more defensive and financially valuable.

Why did BHVN shares surge and then retreat?

Biohaven shares jumped 17.9% to $16.95 on August 26 as investors reacted to the licensing transaction, with trading volume reaching about 15.8 million shares. The stock then fell 4.9% to $16.12 on August 27, but remained approximately 12% above the $14.38 closing price immediately before the agreement was announced. BHVN’s 52-week range stands at roughly $7.48 to $18.57, placing the shares relatively close to the top of that range after the deal.

The initial rally reflects the unusually strong near-term cash component relative to Biohaven’s balance sheet, while the pullback highlights the value investors still assign to retaining full ownership of a late-stage asset. The next RISE3 data could clarify whether Biohaven monetized opakalim at an attractive risk-adjusted price or transferred a potentially much larger franchise too early. Until then, the $795 million headline masks a more interesting capital-allocation debate underneath.