Lecanemab for Alzheimer's Disease

No longer recruiting at 56 trial locations

Overseen By ACTC Recruitment Unit

Age: 18+

Sex: Any

Trial Phase: Phase 3

Sponsor: Eisai Inc.

Must not be taking: Anti-amyloid immunotherapy, Immunoglobulins

Disqualifiers: Pregnancy, Stroke, Seizures, Psychiatric diagnosis, others

Pivotal Trial (Near Approval) This treatment is in the last trial phase before FDA approval

Prior Safety Data This treatment has passed at least one previous human trial

Compensation: Varies

Number of Visits: Unknown

Duration: 216 weeks

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial tests a new treatment called lecanemab for individuals with early signs of Alzheimer's disease. Researchers aim to determine if lecanemab can improve memory and thinking skills while reducing the build-up of brain plaques associated with Alzheimer’s. Participants will receive either lecanemab or a placebo (a harmless substance with no treatment effect) through regular IV infusions over four years. The trial seeks individuals aged 55 to 80 who have been diagnosed with early brain changes related to Alzheimer's and have a close study partner to help track their daily progress. As a Phase 3 trial, this study represents the final step before FDA approval, offering participants a chance to contribute to a potentially groundbreaking treatment.

Will I have to stop taking my current medications?

The trial information does not specify if you need to stop taking your current medications. However, it mentions that taking certain prohibited medications may exclude you from participating. It's best to discuss your current medications with the trial team to see if they are allowed.

Is there any evidence suggesting that this trial's treatments are likely to be safe?

Research has shown that lecanemab, a treatment for Alzheimer's disease, is generally well-tolerated. In one study, about 81% of participants taking lecanemab completed the trial, similar to the 84% completion rate for those on a placebo. Some side effects, such as infusion reactions, were reported but were usually mild to moderate.

The FDA has approved lecanemab for Alzheimer's, indicating that its safety profile is well-understood. However, the FDA recommends more frequent MRI scans to monitor for a specific side effect called ARIA (amyloid-related imaging abnormalities), which can occur in some patients.

Overall, multiple studies have tested lecanemab, and the results support its safety for many people. It is important to discuss potential risks with a healthcare provider before joining a trial. ^{1 2 3 4 5}

Why do researchers think this study treatment might be promising for Alzheimer's?

Lecanemab is unique because it targets amyloid beta, a protein linked to Alzheimer's disease, in a way that is different from most current treatments. While standard options often focus on managing symptoms with medications like donepezil or memantine, lecanemab aims to modify the disease's progression by clearing amyloid plaques from the brain. This approach has the potential to slow down the advancement of Alzheimer's rather than just alleviating its symptoms. Researchers are excited about lecanemab because it offers hope for a more effective strategy in tackling the root cause of the disease.

What evidence suggests that lecanemab might be an effective treatment for Alzheimer's?

Research has shown that lecanemab, one of the treatments studied in this trial for Alzheimer's, may help slow memory and thinking problems. Studies have found that lecanemab reduces amyloid plaques in the brain, which are linked to Alzheimer's progression. In one study, participants taking lecanemab experienced a slower increase in memory and thinking problems compared to those on a placebo, another arm of this trial. Over 18 months, those on lecanemab showed less worsening in symptoms than those who did not take it. This suggests that lecanemab might help people with early Alzheimer's maintain brain function longer. ^{4 6 7 8 9}

Are You a Good Fit for This Trial?

This trial is for men and women aged 55-80 with early signs of Alzheimer's, indicated by certain levels of brain amyloid. Participants must have a good memory score and be generally healthy without severe psychiatric issues or recent drug/alcohol abuse. Women who are pregnant or breastfeeding, people sensitive to monoclonal antibodies, HIV positive individuals, those with uncontrolled bleeding disorders or immunological diseases can't join.

Inclusion Criteria

A45 Trial: Elevated brain amyloid pathology by amyloid PET: defined as approximately greater than (>) 40 Centiloids on screening scan A3 Trial: Intermediate levels of brain amyloid pathology by amyloid PET: defined as approximately 20 to 40 Centiloids on screening scan

I have someone who knows about my daily activities and can share this information with the study team.

Mini Mental State Examination score greater than or equal to (>=) 27 (with educational adjustments) at screening.

Exclusion Criteria

I am using or agree to use birth control as required.

You have any other health problems that, according to the doctor's opinion, need more attention or treatment and may interfere with the study or your safety.

Known or suspected history of drug or alcohol abuse or dependence within 2 years before screening or a positive urine drug test at screening. Participants who test positive for benzodiazepines, opioids, or tetrahydrocannabinol (THC) in urine drug testing need not be excluded unless in the clinical opinion of the investigator this is due to potential drug abuse

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Treatment

Participants receive lecanemab or placebo as IV infusion every two to four weeks for 216 weeks

216 weeks

Every two to four weeks (in-person)

Follow-up

Participants are monitored for safety and effectiveness after treatment

4 weeks

Extension

Participants may continue to receive lecanemab in an extension phase for up to 312 weeks

96 weeks

What Are the Treatments Tested in This Trial?

Interventions

• Lecanemab
• Placebo

Trial Overview The study tests if Lecanemab can slow cognitive decline better than a placebo over 216 weeks in people with preclinical Alzheimer's disease. It also checks if Lecanemab reduces brain amyloid accumulation more effectively than the placebo.

How Is the Trial Designed?

Group I: A45 Trial: Lecanemab 5 mg/kg + 10 mg/kg (Core Study) Experimental Treatment 1 Intervention

Participants will receive lecanemab 5 milligram per kilogram (mg/kg), administered as intravenous (IV) infusion, every two weeks from Week 0 to 6, then 10 mg/kg, administered as IV infusion, every two weeks from Week 8 to 94, and 10 mg/kg, administered as IV infusion, every four weeks from Week 96 to 216 in core study.

Group II: A45 Trial: Lecanemab 10 mg/kg (Extension Phase) Experimental Treatment 1 Intervention

Participants progressing to early Alzheimer's disease (EAD) during the core study (progressors) will receive lecanemab 10 mg/kg, administered as IV infusion, every two weeks after transition to the extension phase through to at least Week 216 from randomization in the core study. Participants completing the core study (completers) will enter extension phase and will receive lecanemab 10 mg/kg, administered as IV infusion, every two weeks for up to Week 312. Eligible participants receiving placebo in core study will continue to extension phase.

Group III: A3 Trial: Lecanemab 5 mg/kg + 10 mg/kg (Core Study) Experimental Treatment 1 Intervention

Participants will receive lecanemab 5 mg/kg, administered as IV infusion, every four weeks from Week 0 to 4, then 10 mg/kg, administered as IV infusion, every four weeks from Week 8 to 216 in core study.

Group IV: A3 Trial: Lecanemab 10 mg/kg (Extension Phase) Experimental Treatment 1 Intervention

Participants progressing to EAD during the core study (progressors) will receive lecanemab 10 mg/kg, administered as IV infusion, every two weeks after transition to the extension phase through to at least Week 216 from randomization in the core study. Participants completing the core study (completers) will enter extension phase and will receive lecanemab 10 mg/kg, administered as IV infusion, every two weeks for up to Week 312. Eligible participants receiving placebo in core study will continue to extension phase.

Group V: A45 Trial: Placebo (Core Study) Placebo Group 1 Intervention

Participants will receive placebo (0.9 percent \[%\] sodium chloride solution), administered as IV infusion, every two weeks from Week 0 to 94, then every four weeks from Week 96 to 216.

Group VI: A3 Trial: Placebo (Core Study) Placebo Group 1 Intervention

Participants will receive placebo (0.9% sodium chloride solution), administered as IV infusion, every four weeks from Week 0 to 216.

Lecanemab is already approved in United States, Japan for the following indications:

Approved in United States as Leqembi for:

• Early symptomatic Alzheimer's disease

Approved in Japan as Leqembi for:

• Early symptomatic Alzheimer's disease

Who Is Running the Clinical Trial?

Eisai Inc.

Lead Sponsor

Trials

524

Recruited

161,000+

Founded

Eisai Inc. was established in 1995 as the U.S. subsidiary of Eisai Co., Ltd.

Headquarters

Woodcliff Lake, NJ, USA

Known For

Neurology and Oncology

Top Products

Aricept (donepezil), Lenvima (lenvatinib), Leqembi (lecanemab), Halaven (eribulin)

Lynn Kramer

Eisai Inc.

Chief Medical Officer since 2019

MD

Tatsuyuki Yasuno

Eisai Inc.

Chief Executive Officer since 2023

MBA from Kellogg School of Management, Northwestern University; Bachelor of Political Science from Waseda University

Biogen

Industry Sponsor

Trials

655

Recruited

468,000+

Daniel Quirk

Biogen

Chief Medical Officer

MD

Christopher A. Viehbacher

Biogen

Chief Executive Officer since 2022

Graduated from Queen's University, Kingston, Ontario, Canada

National Institute on Aging (NIA)

Collaborator

Trials

1,841

Recruited

28,150,000+

Alzheimer's Clinical Trials Consortium

Collaborator

Trials

5

Recruited

2,800+

Published Research Related to This Trial

Lecanemab, a humanized monoclonal antibody, significantly reduces brain amyloid levels and leads to moderate improvements in cognitive function in Alzheimer's patients, as shown in the Clarity AD phase III trial with 18 months of treatment.

While lecanemab demonstrates efficacy in slowing cognitive decline, it is associated with adverse events such as infusion-related reactions (26.4%) and amyloid-related imaging abnormalities (12.6%), raising concerns about its administration and monitoring requirements.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Lecanemab: A Humanized Monoclonal Antibody for the Treatment of Early Alzheimer Disease. Park, J., Simpson, C., Patel, K.[2023]

Lecanemab demonstrated significant efficacy in slowing cognitive decline in patients with early Alzheimer's disease, as evidenced by improvements in multiple cognitive assessment scales across four randomized controlled trials involving 3,108 participants.

While lecanemab was associated with a reduction in amyloid burden, it also presented a risk of adverse events, particularly ARIA-E and ARIA-H, indicating the need for careful monitoring during treatment.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Safety and efficacy of lecanemab for Alzheimer's disease: a systematic review and meta-analysis of randomized clinical trials. Qiao, Y., Chi, Y., Zhang, Q., et al.[2023]

Lecanemab, an IgG1 antibody targeting amyloid-β, received its first approval for treating Alzheimer's disease in the USA on January 6, 2023, specifically for patients with mild cognitive impairment or mild dementia who have confirmed amyloid beta pathology.

The safety and effectiveness of lecanemab have only been established for the specific patient population studied in clinical trials, and there is no data on its use in earlier or later stages of Alzheimer's disease.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Lecanemab: First Approval. Hoy, SM.[2023]

In an 18-month double-blind randomized placebo-controlled trial, lecanemab was effective in clearing amyloid-β in two-thirds of participants with mild cognitive impairment and mild dementia due to Alzheimer's disease.

Lecanemab also significantly reduced the rate of cognitive and functional decline in these individuals, suggesting its potential as a therapeutic intervention for early Alzheimer's disease.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Lecanemab reduces brain amyloid-β and delays cognitive worsening. Knopman, DS.[2023]

Lecanemab has shown promise in treating early Alzheimer's disease, demonstrating a significant reduction in clinical decline among participants in the study.

The study involved a large cohort, providing robust evidence for lecanemab's efficacy, although specific details on the number of subjects and duration were not provided in the overview.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Evidence for lecanemab in early Alzheimer's disease. [2023]

Citations

1. eisai.com eisai.com/news/2025/news202554.html

Early Alzheimer's Patients Continue to Benefit from Four ... Over three years of treatment, including both the core study and the OLE, data showed lecanemab demonstrated a reduction in cognitive decline— ...

2. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC12117801/

Lecanemab in clinical practice: real-world outcomes in early ... Lecanemab, a monoclonal antibody targeting amyloid beta, has recently been approved for treatment of early-stage Alzheimer's disease (AD).

3. nejm.org nejm.org/doi/full/10.1056/NEJMoa2212948

Lecanemab in Early Alzheimer's Disease Lecanemab reduced markers of amyloid in early Alzheimer's disease and resulted in moderately less decline on measures of cognition and function than placebo at ...

4. ema.europa.eu ema.europa.eu/en/news/leqembi-recommended-treatment-early-alzheimers-disease

Leqembi recommended for treatment of early Alzheimer's ... After 18 months of treatment, patients treated with Leqembi had a smaller increase in CDR-SB score than those who received placebo (1.22 versus ...

5. neurology.org neurology.org/doi/10.1212/WNL.0000000000212013

Cost-effectiveness of Lecanemab for the Treatment of Early ... The probability that lecanemab was cost-effective at a threshold of CAD 100,000 was estimated to be 88.5%. Conclusions: Lecanemab represents a ...

6. pubmed.ncbi.nlm.nih.gov pubmed.ncbi.nlm.nih.gov/38730496/

Updated safety results from phase 3 lecanemab study in early ... Updated safety results from phase 3 lecanemab study in early Alzheimer's disease. Alzheimers Res Ther. 2024 May 10;16(1):105. doi: 10.1186 ...

7. media-us.eisai.com media-us.eisai.com/2025-07-21-EISAI-TO-PRESENT-FOUR-YEAR-EFFICACY-AND-SAFETY-DATA-ON-CONTINUOUS-TREATMENT-WITH-LECANEMAB-AT-THE-ALZHEIMERS-ASSOCIATION-INTERNATIONAL-CONFERENCE-2025

Eisai to Present Four-Year Efficacy and Safety Data on ... "The data presented at AAIC 2025 will highlight long-term findings from lecanemab's open-label extension trial, real-world lecanemab case ...

8. bioarctic.com bioarctic.com/en/lecanemab-four-year-efficacy-and-safety-data-to-be-presented-at-aaic-2025/

Lecanemab four-year efficacy and safety data to be presented ... Lecanemab four-year efficacy and safety data to be presented at ... BioArctic has no development costs for lecanemab in Alzheimer's disease ...

9. fda.gov fda.gov/drugs/drug-safety-and-availability/fda-recommend-additional-earlier-mri-monitoring-patients-alzheimers-disease-taking-leqembi-lecanemab

FDA to recommend additional, earlier MRI monitoring for ... Leqembi (lecanemab) is an amyloid beta-directed antibody that FDA approved in 2023 to slow disease progression in patients with Alzheimer's ...