Eisai Co., Ltd. and Biogen Inc. have announced the launch of Leqembi (lecanemab) in South Korea, marking a significant step in Alzheimer's disease treatment. Approved by the Ministry of Food and Drug Safety (MFDS) in May 2024, Leqembi is indicated for adult patients with mild cognitive impairment (MCI) due to Alzheimer's disease (AD) or mild AD dementia (early AD).
Mechanism of Action
Leqembi is a humanized anti-soluble aggregated amyloid-beta (Aβ) monoclonal antibody. It selectively binds to soluble Aβ aggregates (protofibrils) and insoluble Aβ aggregates (fibrils), which are major components of Aβ plaques in AD. By reducing both Aβ protofibrils and Aβ plaques in the brain, Leqembi aims to slow cognitive and functional decline.
Clinical Trial Data
The approval of Leqembi was supported by data from the global Phase 3 Clarity AD clinical trial. The trial demonstrated that Leqembi reduced the Clinical Dementia Rating-Sum of Boxes (CDR-SB) score by 0.45 points compared to placebo at 18 months (95% CI -0.67, -0.23; P<0.001), indicating a 27% slowing of disease progression. An open-label extension (OLE) study showed a 0.95-point reduction in the CDR-SB score after three years of treatment, compared to estimated natural decline.
Alzheimer's Disease in South Korea
In 2021, South Korea had approximately 900,000 dementia patients, with one in ten people over 65 suffering from dementia and one in five from MCI. Alzheimer's dementia accounts for about 70% of all dementia cases. The average annual management cost per dementia patient is 21.1 million South Korean Won (KRW), rising to 33.1 million KRW for severe cases.
Eisai's Commitment
Eisai Korea Inc. will distribute Leqembi and conduct information provision activities. Eisai Korea has been working with healthcare professionals, academic societies, patient groups, and diagnostic companies to create a dementia ecosystem that promotes AD awareness and early diagnosis/treatment. The company will first launch Leqembi in the private market, including a Patient Assistance Program.
Ko Hong-byung, CEO of Eisai Korea, stated, “AD has placed an immense burden on patients and families, with unmet medical needs persisting in the absence of treatments targeting its root causes. The introduction of Leqembi allows for intervention from the mild cognitive impairment stage.”
Future Developments
Eisai Korea is also pursuing regulatory approval for a Leqembi subcutaneous autoinjector, submitted to the FDA on Nov. 1. If approved, this device would enable weekly self-administration, reducing injection time from one hour to approximately 15 seconds, enhancing patient convenience.
Collaboration
Leqembi is the result of a strategic research alliance between Eisai and BioArctic. Eisai leads the development and regulatory submissions globally, with both Eisai and Biogen co-commercializing and co-promoting the product. Eisai has final decision-making authority.
