SK Chemicals said on the 1st that it signed a co-promotion agreement with Korea Eisai to jointly sell Dayvigo (ingredient name lemborexant), Korea's first orexin (DORA) insomnia treatment.
Under the agreement, SK Chemicals will handle sales and marketing for hospitals and clinics with 300 beds or fewer nationwide, while Korea Eisai will be in charge of general hospitals and tertiary general hospitals with more than 300 beds. SK Chemicals will exclusively manage nationwide distribution of the product.
Dayvigo is the first insomnia treatment in Korea in the dual orexin receptor antagonist (DORA) class. Unlike traditional benzodiazepine or non-benzodiazepine hypnotics, it induces sleep by blocking orexin, an arousal neurotransmitter in the brain, from binding to receptors, thereby suppressing excessive arousal.
After receiving approval from the U.S. Food and Drug Administration (FDA), the product has been used in the United States, Japan, Canada and Singapore, among others, and it obtained item approval from the Ministery of Food and Drug Safety in Korea on June 23. It is scheduled to launch in the second half of this year.
Clinical trials also confirmed sleep improvement effects. In the global phase 3 (SUNRISE 1) study of 1,006 insomnia patients aged 55 and older, sleep onset time and sleep maintenance metrics improved compared with the placebo group and the zolpidem extended-release group. In a study of adult patients (SUNRISE 2), dosing for six months or longer showed improvements in sleep-related metrics versus placebo, with effects maintained for up to 12 months.
Korea's insomnia treatment market is growing. According to IQVIA, the market size for insomnia treatments in Korea grew 70.4% from 48 billion won in 2021 to 81.8 billion won in 2025. Data from the Health Insurance Review & Assessment Service (HIRA) also show that the number of patients treated for sleep disorders increased from about 1.03 million in 2020 to 1.3 million in 2024.
Go Hong-byeong, head of Korea Eisai, said, "Dayvigo is a DORA-class therapy being introduced for the first time in Korea and is expected to contribute to a shift in the insomnia treatment paradigm," adding, "Through collaboration with SK Chemicals, which has sales and marketing capabilities in neuroscience, we will ensure a successful launch in the domestic market."
Park Hyun-seon, head of the pharma business at SK Chemicals, said, "Because insomnia is a condition directly tied to quality of life, we will help improve patients' access to treatment by leveraging our nationwide hospital and clinic network and our expertise in neuroscience."