TOKYO and CAMBRIDGE, Mass., Sept. 29, 2025 - (JCN Newswire) - Eisai Co., Ltd. (Headquarters: Tokyo, CEO: Haruo Naito, “Eisai”) and Biogen Inc. (Nasdaq: BIIB, Corporate headquarters: Cambridge, Massachusetts, CEO: Christopher A. Viehbacher, “Biogen”) announced today that humanized anti- soluble aggregated amyloid-beta (Aβ) monoclonal antibody “LEQEMBI®” (generic name: lecanemab) has been approved for once every four weeks intravenous (IV) maintenance dosing by the National Medical Products Administration (NMPA) in China.
In January 2024, LEQEMBI was approved for the treatment of Alzheimer's disease (AD) in patients with mild cognitive impairment (MCI) or mild dementia stage of disease (collectively referred to as early AD) in China. After 18 months of a dosing regimen of 10 mg/kg once every two weeks during initiation phase, a transition to the maintenance dosing regimen of 10 mg/kg once every four weeks may be considered or the regimen of 10 mg/kg once every two weeks may be continued.
AD is a progressive, relentless disease characterized by formation of protein deposits known as plaques made of amyloid-beta aggregates and neurofibrillary tangles made of tau protein in the brains of people living with AD. It is caused by a continuous underlying neurotoxic process that begins before amyloid plaque accumulation and continues after plaque removal.1,2,3,4 The data show that Aβ protofibrils* and tau tangles play roles in the neurodegeneration process,2,3 and LEQEMBI is the only approved therapy that fights AD in two ways – targeting both amyloid plaque and protofibrils, which can impact tau downstream.
Eisai estimates that, as of 2024, there were 17 million patients with MCI or mild dementia due to AD in China in 2024, which is expected to increase with the aging of the population.
Eisai serves as the lead for lecanemab’s development and regulatory submissions globally with Eisai and Biogen co-commercializing and co-promoting the product and Eisai having final decision-making authority. In China, Eisai distributes the product and conducts information provision activities through specialized Medical Representatives.
* Protofibrils are believed to contribute to the brain injury that occurs with AD and are considered to be the most toxic form of Aβ, having a primary role in the cognitive decline associated with this progressive, debilitating condition.1 Protofibrils cause injury to neurons in the brain, which in turn, can negatively impact cognitive function via multiple mechanisms, not only increasing the development of insoluble Aβ plaques but also increasing direct damage to brain cell membranes and the connections that transmit signals between nerve cells or nerve cells and other cells. It is believed the reduction of protofibrils may prevent the progression of AD by reducing damage to neurons in the brain and cognitive dysfunction.4
MEDIA CONTACTS
Eisai Co., Ltd.
Public Relations Department
+81 (0)3-3817-5120
Eisai Europe, Ltd.
(UK, Europe, Australia, New Zealand and Russia)
EMEA Communications Department
+44 (0) 7739 600678
EMEA-comms@eisai.net
Eisai Inc. (U.S.)
Libby Holman
+ 1-201-753-1945
Libby_Holman@eisai.com
Biogen Inc.
Madeleine Shin
+ 1-781-464-3260
public.affairs@biogen.com
INVESTOR CONTACTS
Eisai Co., Ltd.
Investor Relations Department
+81 (0) 3-3817-5122
Biogen Inc.
Tim Power
+ 1-781-464-2442
IR@biogen.com
About LEQEMBI (generic name: lecanemab)
Lecanemab is the result of a strategic research alliance between Eisai and BioArctic. It is a humanized immunoglobulin gamma (IgG1) monoclonal antibody directed against aggregated soluble (protofibril) and insoluble forms of amyloid-beta (Aβ). Protofibrils are believed to contribute to the brain injury that occurs with AD and are considered to be the most toxic form of Aβ, having aprimary role in the cognitive decline associated with this progressive, debilitating condition.
Lecanemab has been approved in 50 countries and is under regulatory review in 10 countries. Following the initial phase with treatment every two weeks for 18 months, intravenous (IV) maintenance dosing with treatment every four weeks was approved in China, the U.S. and others, and applications have been filed in 5 countries and regions.
LEQEMBI's approvals in these countries were based on Phase 3 data from Eisai's, global Clarity AD clinical trial, in which it met its primary endpoint and all key secondary endpoints with statistically significant results. The primary endpoint was the global cognitive and functional scale, Clinical Dementia Rating Sum of Boxes (CDR-SB).1,5 The U.S. FDA approved Eisai’s Biologics License Application (BLA) for subcutaneous maintenance dosing with LEQEMBI IQLIK in August 2025. In September 2025, the rolling sBLA application to the U.S. FDA for the subcutaneous initiation dosing with LEQEMBI IQLIK was also initiated.
Since July 2020 the Phase 3 clinical study (AHEAD 3-45) for individuals with preclinical AD, meaning they are clinically normal and have intermediate or elevated levels of amyloid in their brains, is ongoing. AHEAD 3-45 is conducted as a public-private partnership between the Alzheimer's Clinical Trial Consortium that provides the infrastructure for academic clinical trials in AD and related dementias in the U.S, funded by the National Institute on Aging, part of the National Institutes of Health, Eisai and Biogen. Since January 2022, the Tau NexGen clinical study for Dominantly Inherited AD (DIAD), that is conducted by Dominantly Inherited Alzheimer Network Trials Unit (DIAN-TU), led by Washington University School of Medicine in St. Louis, is ongoing and includes lecanemab as the backbone anti-amyloid therapy.
About the Collaboration between Eisai and Biogen for AD
Eisai and Biogen have been collaborating on the joint development and commercialization of AD treatments since 2014. Eisai serves as the lead of lecanemab development and regulatory submissions globally with Eisai and Biogen co-commercializing and co-promoting the product and Eisai having final decision-making authority.
About the Collaboration between Eisai and BioArctic for AD
Since 2005, Eisai and BioArctic have had a long-term collaboration regarding the development and commercialization of AD treatments. Eisai obtained the global rights to study, develop, manufacture and market lecanemab for the treatment of AD pursuant to an agreement with BioArctic in December 2007. The development and commercialization agreement on the antibody lecanemab back-up was signed in May 2015.
About Eisai Co., Ltd.
Eisai's Corporate Concept is "to give first thought to patients and people in the daily living domain, and to increase the benefits that health care provides." Under this Concept (also known as human health care (hhc) Concept), we aim to effectively achieve social good in the form of relieving anxiety over health and reducing health disparities. With a global network of R&D facilities, manufacturing sites and marketing subsidiaries, we strive to create and deliver innovative products to target diseases with high unmet medical needs, with a particular focus in our strategic areas of Neurology and Oncology.
In addition, we demonstrate our commitment to the elimination of neglected tropical diseases(NTDs), which is a target (3.3) of the United Nations Sustainable Development Goals (SDGs), by working on various activities together with global partners.
For more information about Eisai, please visit www.eisai.com (for global headquarters: Eisai. Co., Ltd.), us.eisai.com (for U.S. headquarters: Eisai, Inc.) or www.eisai.eu (for Europe, Middle East, Africa, Russia, Australia and New Zealand headquarters: Eisai Europe Ltd.), and connect with us on X (global and U.S), LinkedIn (for global, U.S. and EMEA) and Facebook (global).
About Biogen
Founded in 1978, Biogen is a leading biotechnology company that pioneers innovative science to deliver new medicines to transform patients’ lives and to create value for shareholders and our communities. We apply deep understanding of human biology and leverage different modalities to advance first-in-class treatments or therapies that deliver superior outcomes. Our approach is to take bold risks, balanced with return on investment to deliver long-term growth.
For more information, visit: https://www.eisai.com/news/2025/pdf/enews202567pdf.pdf