Biohaven licenses epilepsy drug to SK Biopharma for $400M upfront

What happened

Biohaven Ltd. (NYSE: BHVN), a pharmaceutical company developing treatments for neurological diseases, announced on August 26, 2026 that it entered into a license agreement with SK Biopharmaceuticals Co., Ltd. The deal covers Biohaven's Kv7 ion channel platform, led by opakalim (BHV-7000), an investigational drug for focal epilepsy currently in Phase 2/3 clinical trials.

Under the agreement, SK Biopharmaceuticals will pay Biohaven a $400 million upfront fee — $350 million at closing and $50 million one year later. Biohaven is also eligible for up to $150 million in development and regulatory milestone payments, plus tiered royalties on sales of opakalim and other antiseizure products.

The transaction is expected to close after required antitrust clearances and other customary conditions are met. Biohaven's stock rose 23.16% on the day of the announcement, closing at $17.71, on volume about 4.6 times its average.

Biohaven will continue to conduct ongoing clinical studies and prepare the new drug application for opakalim. SK Biopharmaceuticals is required to use commercially reasonable efforts to develop and seek regulatory approval in the U.S., Europe and Japan.

The agreements

The license agreement grants SK Biopharmaceuticals an exclusive, royalty-bearing, worldwide license to Biohaven's Kv7 ion channel platform, including opakalim and other Kv7 compounds. The license includes the right to grant sublicenses.

Biohaven will also assign to SK Biopharmaceuticals certain rights and obligations under a separate 2022 agreement with Knopp Biosciences LLC. SK Biopharmaceuticals will assume potential milestone obligations of up to $245 million related to regulatory approvals, and a mid-single-digit royalty on worldwide net sales of Kv7 products. These obligations are separate from and not creditable against SK's payments to Biohaven.

The agreements, filed as exhibits to an 8-K with the SEC, include customary termination rights and reversion of intellectual property to Biohaven if the license is terminated.

What this means

An 8-K is a current report companies file with the SEC to notify investors of significant events, such as entering into a material agreement. Item 1.01 covers entry into a definitive agreement; Item 7.01 is a Regulation FD disclosure, which is a way to publicly distribute information to all investors at once. This filing was made on the same day the agreement was signed.

Opakalim is an investigational drug — not yet approved — that activates certain potassium channels in the brain, which can dampen nerve signals that cause seizures. It is in Phase 2/3 trials for focal epilepsy, a common form of epilepsy where seizures start in one part of the brain. The licensing deal gives SK Biopharmaceuticals the rights to develop and sell it globally, while Biohaven retains responsibilities for some ongoing trials and regulatory filings.

The $400 million upfront payment is a substantial sum for a company at Biohaven's stage, and the milestone payments and royalties provide potential future revenue. However, the deal is not yet complete — it is subject to antitrust approvals, meaning regulators must review it for competition concerns before the license becomes effective. If the closing does not happen, the assignment agreement automatically terminates.

For readers unfamiliar with licensing deals: a license is a permission to use another company's technology or product rights, typically in exchange for payments and royalties. The royalty is a percentage of sales paid to the owner. The upfront fee is paid regardless of whether the drug eventually succeeds; milestones are paid only if certain development or regulatory events occur.