EISAI TO PRESENT FOUR-YEAR EFFICACY AND SAFETY DATA ON CONTINUOUS TREATMENT WITH LECANEMAB AT THE ALZHEIMER’S ASSOCIATION INTERNATIONAL CONFERENCE 2025

Latest findings from Eisai’s robust Alzheimer’s disease (AD) pipeline include results from lecanemab long-term data, an immunoassay for measuring amyloid-β protofibrils in cerebrospinal fluid, and a subcutaneous form of lecanemab for continued treatment of AD

AD is a progressive, relentless disease caused by a continuous underlying neurotoxic process that begins before and continues after plaque deposition

NUTLEY, N.J., July 21, 2025 /PRNewswire/ — Eisai Inc. (Headquarters: Tokyo, CEO: Haruo Naito, “Eisai”) announced today that the company will present the latest findings from its robust Alzheimer’s disease (AD) pipeline and research, including our dual-acting, anti-amyloid beta (Aβ) protofibril* antibody for the treatment of AD, lecanemab (generic name, U.S. brand name: LEQEMBI^®), and anti-MTBR (microtubule binding region) tau antibody, etalanetug (E2814), at the Alzheimer’s Association International Conference (AAIC), being held in Toronto and virtually from July 27 – 31. Eisai will present 21 oral presentations, 24 posters, three (3) symposia and two (2) lecanemab product theaters.

Key Oral Lecanemab Presentations

• Four-year Data: On Wednesday, July 30, as part of the “Developing Topics Session: Innovative Therapeutic Approaches” (8:00 – 8:45 AM EDT), initial four-year findings will be presented on lecanemab from the Phase 3 Clarity AD Open-Label Extension in Early Alzheimer’s Disease trial.
• Subcutaneous Maintenance Dosing: A Featured Research Session on Wednesday, July 30 (9:00 – 10:30 AM EDT) will include data on the potential of a new and convenient option for ongoing lecanemab treatment, the subcutaneous formulation for maintenance dosing.
• Real World Case Studies: A Developing Topics Session on Sunday, July 27 (9:00 – 10:30 AM EDT) will include data on real-world case studies and patient pathway learnings from diverse U.S. clinical settings two years post-approval of lecanemab.

Key Lecanemab Poster Presentation

• A Poster Presentation on Monday, July 28 (viewing available from 7:30 AM – 4:15 PM EDT) will share findings on cerebrospinal fluid (CSF) samples collected from the Clarity AD trial and analyzed using the novel, sensitive immunoassay developed to measure Aβ protofibrils in CSF.

Key Oral E2814 Presentation

• A Featured Research Session on Wednesday, July 30 (4:15 – 5:45 PM EDT) will include findings from the Anti-Tau Etalanetug (E2814) with Lecanemab Therapy in Individuals with Dominantly Inherited Alzheimer’s Disease: A First Look at Baseline Characteristics and Impact of 6-Month Lecanemab Treatment on Amyloid PET and Safety in the DIAN-TU-001 NexGen Trial.

“The data presented at AAIC 2025 will highlight long-term findings from lecanemab’s open-label extension trial, real-world lecanemab case studies as well as results on a subcutaneous formulation and dosing regimen that may offer patients more flexibility to continue treatment to fight Alzheimer’s disease,” said Lynn D. Kramer, M.D., FAAN, Chief Clinical Officer, Deep Human Biology Learning (DHBL), Eisai. “We will also share preliminary results from the DIAN-TU-001 NexGen Trial, exploring etalanetug with background lecanemab therapy to slow or prevent the progression of Alzheimer’s disease. As we gain more experience using dual-acting lecanemab in different clinical settings and continue to explore new avenues to improve the diagnosis and treatment of Alzheimer’s disease, we are hopeful about the future. We remain committed to patients and their loved ones who are impacted by this progressive, relentless disease, caused by a continuous underlying neurotoxic process that begins before and continues after plaque is removed from the brain.”

Key Featured Research Sessions

Featured Research Session (FRS), #1-31-FRS-A: Anti-Amyloid Therapies in Clinical Practice: Real World Evidence and Implementation Consideration

4:15 – 5:45 PM EDT, Sunday, July 27

Featured Research Session, #4-13-FRS-C: Lecanemab Subcutaneous Formulation for Maintenance Dosing: The Potential of a New and Convenient Option for Ongoing Treatment in Early Alzheimer’s Disease 

9:00 – 10:30 AM EDT, Wednesday, July 30

Featured Research Session, #4-31-FRS-B: Anti-Tau Etalanetug (E2814) with Lecanemab Therapy in Individuals with Dominantly Inherited Alzheimer’s Disease: A First Look at Baseline Characteristics and Impact of 6-Month Lecanemab Treatment on Amyloid PET and Safety in the DIAN-TU-001 NexGen Trial

4:15 – 5:45 PM EDT, Wednesday, July 30

Key Developing Topics Sessions

Developing Topics On Real-World Data

8:00 – 8:45 AM EDT on Sunday, July 27

Lecanemab Two Years Post-Approval: Real-World Case Series and Patient Pathway Learnings from Diverse US Clinical Settings

9:00 – 10:30 AM EDT on Sunday, July 27

Developing Topics On Innovative Therapeutic Approaches

8:00 – 8:45 AM EDT, Wednesday, July 30

Additional Featured Research and Developing Topics Sessions

Poster Presentations

**Poster viewing time is set from 7:30 AM – 4:15 PM EDT on the date of presentation

Eisai-Sponsored Symposia

Eisai-Sponsored Product Theaters

Product theaters will feature presentations based on real-world clinical experience with lecanemab – providing attendees with an opportunity to hear best practices and expert guidance on using this therapy.

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.

* 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.²

MEDIA CONTACTS

Eisai Inc. (U.S.)

Julie Edelman

+1-862-213-5915

Julie_Edelman@Eisai.com 

[Notes to editors]

1. About lecanemab (LEQEMBI^®)
   
   Lecanemab is the result of a strategic research alliance between Eisai and BioArctic. It is a humanized immunoglobulin gamma 1 (IgG1) monoclonal antibody directed against aggregated soluble (protofibril) and insoluble forms of amyloid-beta (Aβ). Lecanemab is approved and being marketed in the U.S.,³ Japan,⁴ China,⁵ South Korea,⁶ Hong Kong,⁷ Israel,⁸ the United Arab Emirates,⁹ the United Kingdom,¹⁰ Mexico,¹¹ Macau,¹² Oman, Taiwan,¹³ European Union,¹⁴ Qatar, Singapore¹⁵ and Thailand¹⁶ 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).  Eisai has submitted applications for approval of lecanemab in 11 countries and regions.
   
   
   
   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 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 both companies co-commercializing and co-promoting the product and Eisai having final decision-making authority.
   
   
   
   
3. 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.
3. U.S. Food and Drug Administration. 2023. FDA Converts Novel Alzheimer’s Disease Treatment to Traditional Approval. Last accessed: July 2025.
4. Reuters. 2023. Japan approves Alzheimer’s treatment Leqembi by Eisai and Biogen. Last accessed: July 2025.
5. The Pharma Letter. 2024. Brief – Alzheimer drug Leqembi now approved in China. Last accessed: July 2025.
6. Pharmaceutical Technology. 2024. South Korea’s MFDS approves Eisai-Biogen’s LEQEMBI for Alzheimer’s. Last accessed: July 2025.
7. Pharmaceutical Technology. 2024. Hong Kong approves Leqembi for Alzheimer’s treatment. Last accessed: July 2025.
8. Israel Ministry of Health. The Israeli Drug Registry. Leqembi. Last accessed: July 2025.
9. United Arab Emirates Ministry of Health & Prevention. 2024. Registered Medical Product Directory. Leqembi. Last accessed: July 2025.
10. BioSpace. 2024. Leqembi authorized for early Alzheimer’s disease in Great Britain. Last accessed: July 2025.
11. COFEPRIS authorizes innovative treatment for Alzheimer’s patients. Available at: https://bit.ly/3OKks6Y. Last accessed: July 2025.
12. Macau Special Administrative Region Drug Search. ssm.gov.mo/dafweb/. Last accessed: July 2025.
13. Taiwan Food and Drug Administration Assessment Report. http://bit.ly/454Oawe. Last accessed: July 2025.
14. European Medicines Agency. Leqembi | European Medicines Agency (EMA). Last accessed: July 2025.
15. Health Sciences Authority. https://www.hsa.gov.sg/announcements/new-drug-approval/new-drug-approvals—may-2025. Last accessed: July 2025.
16. Thailand Food and Drug Administration, Ministry of Public Health. pertento.fda.moph.go.th/FDA_INFORMATION_DRUG/Home/Phar_Product_Inform_Page?Newcode=U1DR1C1072680001311C. Last accessed: July  2025.  

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SOURCE Eisai Inc.