Eisai to Present the Latest Data on Long-Term, Real-World Treatment with Lecanemab at the AD/PD™ 2026 Annual Meeting

, /PRNewswire/ — Eisai Co., Ltd. (Headquarters: Tokyo, CEO: Haruo Naito, “Eisai”) announced today the company will present the latest findings on lecanemab (generic name, U.S. brand name: LEQEMBI^®), Eisai’s anti-amyloid beta (Aβ) protofibril antibody for the treatment of Alzheimer’s disease (AD), at the 20^th International Conference on Alzheimer’s and Parkinson’s Diseases and Related Neurological Disorders (AD/PD™ 2026) from March 17-21, in Copenhagen, Denmark, and online. The lecanemab data and additional research findings from Eisai’s AD portfolio will be featured in six presentations, including three oral presentations. Eisai will host an industry-sponsored symposium.

Oral and Poster Presentations
Oral presentations will include the latest findings from a United States (U.S.) real-world long-term treatment persistence study, and efficacy and safety outcomes in apolipoprotein E ε4 (ApoEε4) homozygous carriers in a U.S. multicenter real-world study. In addition, four-year data from the Clarity AD Open-Label Extension trial in ApoEε4 non-carriers and heterozygotes, and a genome-wide association study on novel genetic variants associated with cognitive decline in AD will be presented as posters.

Eisai Symposium – Continue Life Their Way: Early Intervention in Alzheimer’s Disease
Eisai is sponsoring a symposium featuring four leading global experts in the field of AD, on the topics of why early intervention matters, continuing early AD treatment and real-world outcomes. The symposium aims to enhance understanding of the value of early and continued anti-amyloid treatment in early AD by exploring how real-world evidence can support confident patient assessment in clinical practice, and how to recognize AD as a chronic condition that requires a multidisciplinary approach to care.

AD/PD™ 2026 Presentations Relating to Eisai’s Key Compounds and Research

Poster viewing time is from 7:30 on Tuesday, March 17 to 11:10 on Thursday, March 19 (CET).

Eisai-Sponsored Symposium: Industry Symposium 05
Wednesday, March 18, 11:10- 12:50 (CET)

Eisai serves as the lead of lecanemab development and regulatory submissions globally with both Eisai and Biogen co-commercializing and co-promoting the product and Eisai having final decision-making authority.

[Notes to editors]

1. About lecanemab (generic name, brand name: LEQEMBI^®)
   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).

   Lecanemab has been approved in 53 countries and regions including Japan, the United States, China, Europe, South Korea, Taiwan, and Saudi Arabia, and is under regulatory review in 6 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 7 countries including the U.S., China, the UK, and others, and applications have been filed in 10 countries and regions. The U.S. FDA approved Eisai’s Biologics License Application (BLA) for subcutaneous maintenance dosing with LEQEMBI IQLIK in August 2025. A Supplemental Biologics License Application (sBLA) for initiation treatment was accepted in January 2026. The sBLA has been granted Priority Review, with a Prescription Drug User Fee Act (PDUFA) action date of May 24, 2026. In November 2025, an application for a subcutaneous injectable formulation in Japan was submitted. In January 2026, the Biologics License Application (BLA) for the subcutaneous formulation was accepted in China. In December 2025, Lecanemab (IV) has been included in the “Commercial Insurance Innovative Drug List”, recently introduced by the National Healthcare Security Administration (NHSA) of China.

   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.

2. About Protofibrils
   Protofibrils are believed to contribute to the brain injury that occurs with AD and are considered to be the most toxic form of soluble 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.²
3. 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 LEQEMBI development and regulatory submissions globally with both companies co-commercializing and co-promoting the product and Eisai having final decision-making authority.
4. 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.

References

1. Amin L, Harris DA. Aβ receptors specifically recognize molecular features displayed by fibril ends and neurotoxic oligomers. Nat Commun. 2021;12: 3451. doi:10.1038/s41467-021-23507-z.
2. Ono K, Tsuji M. Protofibrils of Amyloid-β are Important Targets of a Disease-Modifying Approach for Alzheimer’s Disease. Int J Mol Sci. 2020;21(3):952. doi: 10.3390/ijms21030952. PMID: 32023927; PMCID: PMC7037706.

SOURCE Eisai Inc.