SK Biopharmaceuticals signs $795 million licensing deal with Biohaven for epilepsy drug

SK Biopharmaceuticals will spend up to $795 million to bring a new epilepsy drug developed by U.S. biotech firm Biohaven to the U.S. market by 2029.

The Korean bio company said in a regulatory filing Wednesday that it signed a global exclusive licensing agreement with Biohaven Bioscience Ireland Limited, the Irish subsidiary of Biohaven, for the epilepsy drug candidate Opakalim (BHV-7000), related compounds that work the same way and the drug development platform behind them.

"For pharmaceutical and biotech companies to achieve sustainable growth, building a pipeline that looks 15 years ahead is crucial," SK Biopharmaceuticals CEO Lee Dong-hoon said at a press briefing held afterward in central Seoul. "This Opakalim acquisition is a strategic decision to build a growth backbone for the post-cenobamate era, while at the same time maximizing the value of the direct sales infrastructure we have built in the U.S. over several years."

SK Biopharm already sells another epilepsy drug, cenobamate, marketed as Xcopri, an antiseizure medication with stronger effects aimed at severe cases but also linked to stronger side effects, including dizziness and sedation. Opakalim is intended for the broader general neurology market, where physicians tend to be more sensitive to side effects.

Opakalim is being developed to treat partial-onset seizures, the most common form of epilepsy, in which abnormal electrical activity begins in one area of the brain. The drug works by activating a protein called Kv7, which helps regulate how easily brain cells fire; turning it on calms overactive neurons. Opakalim is currently being tested in two ongoing Phase 2/3 trials, RISE2 and RISE3, combined studies that assess both effectiveness and safety in the same trial rather than as separate stages.

The company strategically chose a related drug, given the direct sales network it has already built in the U.S. With Xcopri, the company's second-quarter operating profit surged 56.9 percent on year to 97.1 billion won ($70.2 million), while revenue increased 40.3 percent on year to 247.4 billion won.

As Xcopri's U.S. substance patent is set to expire in October 2032, SK Biopharm chose Opakalim as its next-generation product. Opakalim's patent runs through 2039.

"If Xcopri is a powerful game-changer targeting severe patients, Opakalim is the perfect complement — one that general neurologists can comfortably prescribe to early-stage patients without worrying about side effects," Lee said. "By combining the two drugs, we will capture the entire U.S. epilepsy market like a net."

The deal is worth up to $795 million in total. Of that, $400 million is a nonrefundable upfront payment, split into $350 million at closing and an additional $50 million a year later. SK Biopharmaceuticals could pay up to $395 million more in milestone payments, additional sums triggered as the drug clears certain development and regulatory benchmarks.

Of the milestone payments, up to $335 million is linked to Opakalim specifically. The company could pay up to $60 million more for other compounds that act on the same Kv7 protein. Once products reach the market, SK Biopharmaceuticals will also pay royalties based on net sales.

The contract runs for 10 years after product launch, or until the patent expires or regulatory exclusivity, the period during which no generic or competing version can be sold, ends, whichever comes last.

Biohaven will continue to run Opakalim's ongoing clinical trials, though SK Biopharmaceuticals will cover the related development costs.

BY LEE JAE-LIM [[email protected]]