SK biopharmaceuticals announced on Tuesday that its partner, Ono Pharmaceutical, has submitted a New Drug Application (NDA) for the epilepsy drug cenobamate to Japan's Pharmaceuticals and Medical Devices Agency (PMDA).

Japan has approximately 1 million patients with epilepsy, about 30 percent of whom are resistant to existing antiepileptic drugs. This NDA submission aims to provide Japanese patients with a new treatment option and strategically expand cenobamate's presence in the Northeast Asian market, including Japan.

The phase 3 clinical trial (YPK3089C035) underpinning this NDA submission was conducted in adult patients with partial-onset seizures in Korea, China, and Japan. It demonstrated that cenobamate was effective in patients whose seizures remained uncontrolled despite treatment with existing antiepileptic drugs.

Building on this, SK biopharmaceuticals’ partners in China and Korea submitted their NDAs late last year and early this year, respectively. With Ono Pharmaceutical's Japanese NDA submission, commercialization procedures have now commenced in all three Northeast Asian countries.

Ono Pharmaceutical, headquartered in Osaka, Japan, is a research and development (R&D)-focused pharmaceutical company that concentrates on developing innovative new drugs for diseases with high unmet medical needs, such as cancer, immunology, and neurology.

SK biopharmaceuticals signed a technology export agreement with Ono Pharmaceutical in October 2020 for the development and commercialization of cenobamate in Japan. SK biopharmaceuticals will receive milestone payments tied to regulatory submissions and approvals, as well as sales milestones and royalties upon commercialization.

SK biopharmaceuticals has successfully commercialized cenobamate in 25 major global markets, including the U.S. and Europe, through direct sales and technology export. The company is now pursuing market expansion through indication and age group extensions. It recently reported positive topline results from a phase 3 clinical trial for primary generalized tonic-clonic (PGTC) seizures in adolescents and adults, conducted to expand its indications. Detailed clinical results are scheduled to be presented at the 2025 American Epilepsy Society (AES) meeting in December.

“Japan is a major market, ranking second globally in the epilepsy market among single countries after the United States,” SK biopharmaceuticals CEO Lee Dong-hoon said. “With this NDA submission, cenobamate has entered the commercialization process in all three Northeast Asian countries—Korea, China, and Japan—which is highly significant for expanding our position within the Asian market. We expect to provide new treatment opportunities to more patients.”