Eisai to Present New Five-Year Lecanemab Data and Real-World Alzheimer's Disease Research at the 19th Clinical Trials on Alzheimer's Disease (CTAD) Conference

BOSTON, November 1, 2026 - (JCN Newswire) - Eisai Co., Ltd. announced today that it will present new Alzheimer’s disease (AD) research at the 19th Clinical Trials on Alzheimer’s Disease (CTAD) Conference, taking place November 16-19, 2026, in Boston and online.

Highlights include new findings on lecanemab (brand name: LEQEMBI®), Eisai’s anti-amyloid beta (Aβ)protofibril antibody for the treatment of Alzheimer’s disease, from five-year treatment in the Clarity AD longterm study, data from the real-world LEADER study in diverse US clinical settings, and research exploringsafety, biomarkers and Alzheimer’s disease-related co-pathology.

Eisai’s CTAD 2026 scientific program includes a dedicated LEADER symposium, five oral presentations and19 posters.

New Real-World LEADER Data Demonstrate How Lecanemab Is Being Used in Clinical Practice

A standalone symposium will feature new analyses from the LEADER study, a multicenter, real-world,retrospective study examining lecanemab use in early Alzheimer’s disease across diverse US treatmentcenters three years after FDA approval.

Five-Year Clarity AD Data Highlight Long-Term Outcomes with Lecanemab

A featured oral presentation will report findings through five years of lecanemab treatment in the Clarity ADstudy, including the core and long-term extension phases, providing one of the longest-term follow-up datasets reported to date for an approved anti-amyloid therapy in Alzheimer's disease.

Additional key oral presentations will examine:

- Real-world lecanemab safety, including ARIA rates and safety profiles reported across multiple countries
- Lecanemab treatment and α-synuclein co-pathology in the Clarity AD CSF substudy

Eisai’s CTAD 2026 poster presentations will include additional research on real-world lecanemab treatment experience, including analyses of effectiveness, safety, treatment persistence and subcutaneous administration. Other posters will examine the effect of lecanemab on key biological processes involved inAD, including protein changes in CSF, biomarker-based diagnosis, long-term treatment outcomes anddisease biology across the Alzheimer’s continuum.

“The data being presented at CTAD this year reflect our commitment to advancing the field of Alzheimer’s disease through scientific innovation and collaboration that lead to a deeper understanding of patient needs,” said Lynn D. Kramer, M.D., FAAN, Chief Clinical Officer, Deep Human Biology Learning (DHBL), Eisai. “From long-term outcomes and real-world experience to new insights in diagnosis and care delivery, these findings underscore the work we’re doing to make progress for patients, families and clinicians.”

CTAD 2026 Presentations Relating to Eisai's Key Compounds and Research

Wednesday, November 18, 11:00-11:40 AM ET
Symposium: Lecanemab Three Years Post-Approval: A Comprehensive Multicenter, Real-World, Retrospective Study (LEADER) in Diverse US Clinical Settings

1. Real-World Lecanemab Utilization and Outcomes from Initiation Through Maintenance Therapy in Early Alzheimer’s Disease: A Multicenter, Real-World, Retrospective Study(LEADER)
2. Sex-Based Outcomes of Lecanemab in Early Alzheimer’s Disease: A Multicenter, Real-World Retrospective Study(LEADER)
3. At-Home Subcutaneous Lecanemab Administration: A Multicenter, Real-World, Retrospective Study(LEADER)

*Poster Viewing Time:
Poster Session 1: November 16 (2:00 PM) - November 17 (5:30 PM)
Poster Session 2: November 18 (7:15 AM - 5:30 PM)
Poster Session 3: November 19 (7:15 AM - 5:00 PM)

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

This release discusses investigational uses of agents in development and is not intended to convey conclusions about efficacy or safety. There is no guarantee that such investigational agents will successfully complete clinical development or gain health authority approval.

MEDIA CONTACTS

Public Relations Department,
Eisai Co., Ltd.
+81-(0)3-3817-5120

Eisai Europe, Ltd.
(Europe, Australia, New Zealand and Russia)
EMEA Communications Department
+44 (0) 7739-600-678
EMEA-comms@eisai.net

Eisai, Inc. (U.S.)
Julie Edelman
+1-862-213-5915
Julie Edelman@eisai.com  

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 9 countries including the U.S., China, the UK, and others, and applications have been filed in 11 countries and regions. The U.S. FDA approved Eisai’s Biologics License Application (BLA) for subcutaneous maintenance dosing (360mg) with LEQEMBI IQLIK in August 2025. For subcutaneous initiation treatment (500 mg), approval was obtained in the U.S. in July 2026 and China and Japan in September 2026, and applications are under review in 4 countries.

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 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

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

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.