SK Biopharmaceuticals to In-License Epilepsy Drug Candidate 'Opakalim'

Paves the Way to Launch its Second Innovative Drug Directly in the U.S.

• Announces agreement to in-license near-commercial candidate at a press conference
• Targets U.S. commercial launch as early as 2029… Upfront and milestone payments related to the Kv7 platform of up to $795M, plus tiered royalties to Biohaven on U.S. net sales of opakalim and additional royalties on ex-U.S. net sales of opakalim and on certain other products
• Strong potential of success and clear differentiation points validated… Stepping up to another level

SEOUL, South Korea, Aug. 26, 2026 /PRNewswire/ -- SK Biopharmaceuticals Co., Ltd. (www.skbp.com/ CEO: Donghoon Lee) held a press conference on August 26^th and announced that it has entered into an agreement to in-license opakalim, an investigational antiseizure medication, from Biohaven Ltd. and/or its wholly owned subsidiaries ("Biohaven").

This in-licensing is part of SK Biopharmaceuticals' ongoing strategy to leverage its commercial infrastructure through the addition of a new product (second product). Upon regulatory approval, as planned, the company will step up beyond its status as a 'one commercial product company' and become the only drug development company in South Korea that directly markets multiple innovative medicines in the global market.

Opakalim is a selective Kv7 potassium channel activator that has garnered attention as a novel anti-seizure therapy for epilepsy. In clinical studies conducted to date, the candidate has demonstrated a favorable safety and tolerability profile. The candidate is currently in Phase 2/3 studies for treatment of partial-onset seizures (POS) in adults. Provided clinical milestones remain on track, initial top-line results from the RISE 3 trial are expected by the end of this year. Following a second data readout in 2028, SK Biopharmaceuticals aims to launch the product in the U.S. market as early as 2029.

The agreement provides for upfront and milestone payments related to the Kv7 platform totaling up to $795 million.^[1] This amount consists of $400 million in upfront cash consideration, with $350 million payable at closing and an additional $50 million payable one year after closing, and up to $395 million in development and regulatory milestone payments. Under the agreement, a portion of milestones and royalty payments is payable to Knopp Biosciences, the original developer. Closing of the transaction is subject to receipt of required antitrust clearances and other customary closing conditions.

Upon closing, SK Biopharmaceuticals will obtain exclusive global development and commercialization rights to opakalim. The company will also obtain access to the Kv7 discovery platform and related Kv7 targeting compounds generated through the platform, opening up additional opportunities to expand its pipeline in the future through this strategic arrangement.

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."

Cenobamate (U.S. brand name: XCOPRI®), SK Biopharmaceuticals' innovative anti-seizure medication, has settled on a growth trajectory by becoming the No. 1 branded new drug in the U.S. epilepsy market this year. Upon regulatory approval of opakalim, SK Biopharmaceuticals plans to prioritize the launch of opakalim through its U.S. subsidiary, SK Life Science, where it has built a dedicated epilepsy commercial organization with a purpose-built neurology field force of over 150 professionals and established coverage of epilepsy-center and neurologists.

In particular, this strategic approach is expected to enhance SK Biopharmaceuticals' ability to address the diverse unmet needs of patients with epilepsy by combining the distinct strengths of cenobamate and opakalim. With two differentiated assets, the company aims to broaden treatment options and deliver meaningful benefits to more patients. This in-licensing transaction also represents an important step toward building a differentiated epilepsy portfolio focused on improving patient outcomes.

Vlad Coric, M.D., Chairman and Chief Executive Officer of Biohaven, commented, "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." Dr. 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."

"As this news has been long awaited, the agreement to in-license opakalim carries immense strategic significance to our company," said Donghoon Lee, CEO of SK Biopharmaceuticals. "This propels SK Biopharmaceuticals to another level – transitioning into a multi-product company that directly commercializes therapies in the U.S. market."

He also stated, "Beyond introducing early-stage candidates from Asian biotech companies and U.S. research institutions, we have now agreed to in-license a late-stage candidate with near-term trial readouts from a publicly listed U.S. 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.

Meanwhile, SK Biopharmaceuticals is continuously strengthening its mid-to-long-term growth and profitability foundations through lifecycle management initiatives for cenobamate, such as indication expansion and formulation diversification. Early this year, the company submitted a New Drug Application (NDA) for an oral suspension formulation and is pursuing supplemental New Drug Applications (sNDAs) within the year to expand the label to include primary generalized tonic-clonic (PGTC) seizures and pediatric patients.

Global market expansion is also being conducted in parallel. In China, commercialization commenced in March through SK Biopharmaceuticals' local partner, Ignis Therapeutics. In Latin America, cenobamate was also successfully launched this year in Peru, Chile, and Brazil through SK Biopharmaceuticals' partner, Eurofarma. Procedures for regulatory approval in Japan and launch preparations in South Korea are also progressing smoothly.

Advisors

Nomura Securities International, Inc. is serving as exclusive financial advisor and Paul Hastings LLP is serving as legal counsel to SK Biopharmaceuticals. J.P. Morgan Securities LLC is serving as exclusive financial advisor and Sullivan & Cromwell LLP is serving as legal advisor to Biohaven.

About Opakalim and the Kv7 Ion Channel Platform

Opakalim is a next-generation, selective Kv7.2/7.3 potassium channel activator targeting a clinically validated mechanism of action for the treatment of epilepsy. Opakalim is differentiated from both first- and second-generation Kv7 activators by its selectivity for the Kv7.2/7.3 heteromeric channels that are the predominant regulators of neuronal excitability, with substantially less activity at GABA receptors. This selectivity profile is hypothesized to contribute to opakalim's favorable tolerability, including the low rates of somnolence, dizziness, and fatigue observed in clinical studies to date. Opakalim has been studied in more than 1,200 participants across multiple clinical trials. There are currently two Phase 2/3 randomized, double-blind, placebo-controlled studies (NCT06132893 and NCT06309966) evaluating opakalim versus placebo as adjunctive therapy for refractory focal onset epilepsy, along with an open-label extension study (NCT06443463) assessing long-term efficacy and safety.

About Biohaven

Biohaven Ltd. is a public U.S. biopharmaceutical company focused on the discovery, development, and commercialization of life-changing treatments across immunology, neuroscience, and oncology. Biohaven is advancing an innovative portfolio of therapeutics built on proven drug development experience and multiple proprietary drug development platforms, including Kv7 ion channel modulation for epilepsy. For more information, visit www.biohaven.com.

About SK Biopharmaceuticals Co., Ltd. And SK Life Science, Inc

SK Biopharmaceuticals Co., Ltd. is part of SK Group, South Korea's second-largest conglomerate. SK Group is a collection of global industry-leading companies driving innovations in energy, advanced materials, biopharmaceuticals, and digital business. Based in Seoul, SK invests in building sustainable businesses around the world with a shared commitment to reducing global greenhouse gas emissions. SK companies combined have $151 billion in global annual revenue and employ more than 100,000 people worldwide. SK Group is one of TIME's 100 Most Influential Companies of 2023. SK Inc., the parent company of SK Biopharmaceuticals, continues to enhance its portfolio value by executing long-term investments with a number of competitive subsidiaries in various business areas, including pharmaceuticals and life science, energy and chemicals, information and telecommunication, and semiconductors. In addition, SK Inc. is focused on reinforcing its growth foundations through profitable and practical management based on financial stability, while raising its enterprise value by investing in new future growth businesses. For more information about SK Inc., visit https://sk-inc.com/en/main/mainpage.aspx. For more information about SK Biopharmaceuticals, visit www.skbp.com/eng.

SK Life Science, Inc., with headquarters in Paramus, New Jersey, is a U.S. subsidiary of SK Biopharmaceuticals Co., Ltd., a pioneering South Korean biopharmaceutical company in drug development and commercialization. Together, they are advancing innovative treatments for central nervous system (CNS) disorders and oncology, with eight compounds currently in development. Utilizing target-based drug discovery, high-throughput organic screening/high content screening, computer-aided drug design, and combinatorial chemistry, the companies drive R&D efforts in biology/discovery, medicinal chemistry, pharmacology, and clinical development. For more information, visit www.SKLifeScienceInc.com.

About XCOPRI® (cenobamate tablets) CV 

Cenobamate is an antiseizure medication (ASM) discovered and developed by SK Biopharmaceuticals and SK Life Science. Cenobamate reduces neuronal excitability through a unique dual mechanism of action, preferentially inhibiting the persistent sodium current and enhancing GABAergic inhibition at the type A γ-aminobutyric acid (GABA_A) ion channel. The precise mechanism by which cenobamate exerts its therapeutic effect is unknown.

Cenobamate is marketed under the brand name XCOPRI® in the U.S. by SK Life Science, Inc. Additionally, XCOPRI is commercialized in Canada and Israel by SK Biopharmaceuticals' partners, Paladin Labs Inc. and Dexcel Ltd. Cenobamate is marketed as ONTOZRY® by Angelini Pharma S.p.A. in Europe, the UK, and Switzerland.

IMPORTANT SAFETY INFORMATION AND INDICATION FOR XCOPRI® (cenobamate tablets) CV

DO NOT TAKE XCOPRI IF YOU:

• Are allergic to cenobamate or any of the other ingredients in XCOPRI.
• Have a genetic problem (called Familial Short QT syndrome) that affects the electrical system of the heart.

XCOPRI CAN CAUSE SERIOUS SIDE EFFECTS, INCLUDING:

Allergic reactions: XCOPRI can cause serious skin rash or other serious allergic reactions which may affect organs and other parts of your body like the liver or blood cells. You may or may not have a rash with these types of reactions. Call your healthcare provider right away and go to the nearest emergency room if you have any of the following: swelling of your face, eyes, lips, or tongue, trouble swallowing or breathing, a skin rash, hives, fever, swollen glands, or sore throat that does not go away or comes and goes, painful sores in the mouth or around your eyes, yellowing of your skin or eyes, unusual bruising or bleeding, severe fatigue or weakness, severe muscle pain, frequent infections, or infections that do not go away. Take XCOPRI exactly as your healthcare provider tells you to take it. It is very important to increase your dose of XCOPRI slowly, as instructed by your healthcare provider.

QT shortening: XCOPRI may cause problems with the electrical system of the heart (QT shortening). Call your healthcare provider if you have symptoms of QT shortening including fast heartbeat (heart palpitations) that last a long time or fainting.

Suicidal behavior and ideation: Antiepileptic drugs, including XCOPRI, may cause suicidal thoughts or actions in a very small number of people, about 1 in 500. Call your health care provider right away if you have any of the following symptoms, especially if they are new, worse, or worry you: thoughts about suicide or dying; attempting to commit suicide; new or worse depression, anxiety, or irritability; feeling agitated or restless; panic attacks; trouble sleeping (insomnia); acting aggressive; being angry or violent; acting on dangerous impulses; an extreme increase in activity and talking (mania); or other unusual changes in behavior or mood.

Liver problems: XCOPRI may cause liver problems. Your healthcare provider will do blood tests to check your liver before you start XCOPRI and while you take XCOPRI if needed. Tell your healthcare provider right away if you have any symptoms of liver problems, such as: yellowing of the skin and eyes (jaundice), nausea, vomiting, unusual darkening of the urine, or feeling tired or weak.

Nervous system problems: XCOPRI may cause problems that affect your nervous system. Symptoms of nervous system problems include: dizziness, trouble walking or with coordination, feeling sleepy and tired, trouble concentrating, remembering, and thinking clearly, and vision problems. Do not drive, operate heavy machinery, or do other dangerous activities until you know how XCOPRI affects you.

Do not drink alcohol or take other medicines that can make you sleepy or dizzy while taking XCOPRI without first talking to your healthcare provider.

DISCONTINUATION: 

Do not stop taking XCOPRI without first talking to your healthcare provider. Stopping XCOPRI suddenly can cause serious problems. Stopping seizure medicine suddenly in a patient who has epilepsy can cause seizures that will not stop (status epilepticus).

DRUG INTERACTIONS: 

XCOPRI may affect the way other medicines work, and other medicines may affect how XCOPRI works. Do not start or stop other medicines without talking to your healthcare provider. Tell healthcare providers about all the medicines you take, including prescription and over-the-counter medicines, vitamins and herbal supplements.

PREGNANCY AND LACTATION: 

XCOPRI may cause your birth control medicine to be less effective. Talk to your health care provider about the best birth control method to use.

Talk to your health care provider if you are pregnant or plan to become pregnant. It is not known if XCOPRI will harm your unborn baby. Tell your healthcare provider right away if you become pregnant while taking XCOPRI. You and your healthcare provider will decide if you should take XCOPRI while you are pregnant. If you become pregnant while taking XCOPRI, talk to your healthcare provider about registering with the North American Antiepileptic Drug (NAAED) Pregnancy Registry. The purpose of this registry is to collect information about the safety of antiepileptic medicine during pregnancy. You can enroll in this registry by calling 1-888233-2334 or go to www.aedpregnancyregistry.org.

Talk to your health care provider if you are breastfeeding or plan to breastfeed. It is not known if XCOPRI passes into breastmilk. Talk to your healthcare provider about the best way to feed your baby while taking XCOPRI. 

COMMON SIDE EFFECTS: 

The most common side effects in patients taking XCOPRI include dizziness, sleepiness, headache, double vision, and feeling tired. 

These are not all the possible side effects of XCOPRI. Tell your healthcare provider if you have any side effect that bothers you or that does not go away. For more information, ask your healthcare provider or pharmacist. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.

DRUG ABUSE: 

XCOPRI is a federally controlled substance (CV) because it can be abused or lead to dependence. Keep XCOPRI in a safe place to prevent misuse and abuse. Selling or giving away XCOPRI may harm others and is against the law.

INDICATION: 

XCOPRI is a prescription medicine used to treat partial-onset seizures in adults 18 years of age and older. It is not known if XCOPRI is safe and effective in children under 18 years of age. 

Please see additional patient information in the Medication Guide. This information does not take the place of talking with your healthcare provider about your condition or your treatment. 

Please see full Prescribing Information.

XCOPRI® and ONTOZRY® are registered trademarks of SK Biopharmaceuticals Co., Ltd.

Media Contact: 
SK Biopharmaceuticals Public Relations Team
[email protected] 

SOURCE SK Biopharmaceuticals. Co., Ltd.

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