SK Biopharmaceuticals is making a major push to become a multi-product global drug company, striking a deal to in-license Biohaven’s late-stage epilepsy drug candidate opakalim and targeting a potential US launch as early as 2029.

 

The agreement gives SK Biopharmaceuticals exclusive global development and commercialization rights to opakalim, an investigational antiseizure medicine that activates Kv7 potassium channels. 

 

The deal includes up to $795 million in upfront and milestone payments related to the Kv7 platform, alongside tiered royalties on U.S. net sales and additional royalties tied to ex-US sales and certain other products.

 

If opakalim wins regulatory approval, SK Biopharmaceuticals says it will become the only South Korean drug-development company directly marketing multiple innovative medicines globally.

 

Opakalim is currently being evaluated in Phase 2/3 trials for partial-onset seizures in adults. If development stays on track, initial top-line results from the RISE 3 trial are expected by the end of 2026, followed by a second data readout in 2028. SK Biopharmaceuticals is targeting a US launch as early as 2029.

 

The financial terms include $400 million in upfront cash, with $350 million due at closing and another $50 million payable one year later, plus up to $395 million in development and regulatory milestone payments. A portion of the milestone and royalty payments will be payable to Knopp Biosciences, the original developer of the technology.

 

Once completed, the deal will give SK Biopharmaceuticals access not only to opakalim but also to Biohaven’s Kv7 discovery platform and related compounds, potentially creating additional opportunities to expand the company’s pipeline.

 

SK Biopharmaceuticals commented, “As with any clinical-stage product candidate, risks associated with clinical trials, regulatory approval, and commercialization remain.” 

 

However, the company added, “Our company has accumulated end-to-end capabilities spanning discovery, clinical trials, regulatory approvals, and commercialization in the epilepsy field over the past 30 years. Following an extensive evaluation by our epilepsy experts, we believe the candidate has strong potential for success and offers meaningful differentiation, particularly with respect to its favorable tolerability profile.”

 

The deal builds directly on the commercial momentum of cenobamate, sold in the United States as XCOPRI. SK Biopharmaceuticals says the drug has become the No. 1 branded new drug in the U.S. epilepsy market this year.

 

That existing commercial platform is expected to give opakalim a ready-made launch infrastructure if it reaches the market.

 

SK plans to commercialize the drug through its US subsidiary, SK Life Science, which has established a dedicated epilepsy organization and a neurology field force of more than 150 professionals covering epilepsy centers and neurologists.

 

The company sees the two medicines as complementary rather than competing assets, arguing that their distinct characteristics could allow it to address a broader range of unmet needs among people with epilepsy.

 

Biohaven CEO Vlad Coric said the drug's profile could be a key differentiator.

 

“Opakalim is one of the most exciting assets we have advanced; a selective Kv7.2/7.3 activator designed to deliver meaningful efficacy with low incidence of the burdensome central nervous system side effects, including sedation and dizziness, associated with so many antiseizure medicines.”

 

Coric added, “SK Biopharmaceuticals is an ideal partner having launched XCOPRI and is the only company to bring a new antiseizure medicine for partial-onset (focal) seizures to patients in the U.S. since 2020.”

 

For SK Biopharmaceuticals CEO Donghoon Lee, the agreement represents a broader transformation of the company.

 

“As this news has been long awaited, the agreement to in-license opakalim carries immense strategic significance to our company. This propels SK Biopharmaceuticals to another level – transitioning into a multi-product company that directly commercializes therapies in the US market.”

 

Lee said the transaction also marks a shift in the company's approach to business development.

 

“Beyond introducing early-stage candidates from Asian biotech companies and US research institutions, we have now agreed to in-license a late-stage candidate with near-term trial readouts from a publicly listed US biopharmaceutical company. This clearly signals that our company has stepped into the major leagues across all dimensions.”

 

“Going forward, we will continue to lead the way in restoring market trust in K-Bio and establishing a new benchmark for sustainable growth through tangible achievements,” he concluded.

 

Opakalim is a selective Kv7.2/7.3 potassium channel activator designed to target a clinically validated mechanism involved in epilepsy. The company says its selectivity distinguishes it from earlier-generation Kv7 activators and may contribute to lower rates of somnolence, dizziness and fatigue.

 

More than 1,200 participants have been studied in clinical trials of opakalim to date. Two Phase 2/3 randomized, double-blind, placebo-controlled studies are evaluating the drug as adjunctive therapy for refractory focal-onset epilepsy, alongside an open-label extension study assessing longer-term efficacy and safety.

 

The deal comes as SK Biopharmaceuticals continues to expand the commercial potential of cenobamate. The company is pursuing additional indications and formulations, including an oral suspension, as well as label expansion for primary generalized tonic-clonic seizures and pediatric patients.