Clinical Trial

AHEAD 3-45 Study: A Study to Evaluate Efficacy and Safety of Treatment With Lecanemab in Participants With Preclinical Alzheimer's Disease and Elevated Amyloid and Also in Participants With Early Preclinical Alzheimer's Disease and Intermediate Amyloid

Active, Not Recruiting Phase 3
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Summary
The primary purpose of this study is to determine whether treatment with lecanemab is superior to placebo on change from baseline of the Preclinical Alzheimer Cognitive Composite 5 (PACC5) at 216 weeks of treatment (A45 Trial) and to determine whether treatment with lecanemab is superior to placebo in reducing brain amyloid accumulation as measured by amyloid positron emission tomography (PET) at 216 weeks of treatment (A3 Trial). This study will also evaluate the long-term safety and tolerability of lecanemab in participants enrolled in the Extension Phase.
Protocol Amendment History 27 amendments
This ClinicalTrials.gov record has been amended 27 times since 2020-07-09; most recent amendment 2026-06-03.
Status change: Recruiting → Active, Not Recruiting 2024-12-31
Status change: Not Yet Recruiting → Recruiting 2020-07-23
Trial Details
NCT Number NCT04468659
Lead Sponsor Eisai Inc.
Collaborators: Alzheimer's Clinical Trials Consortium, Biogen, National Institute on Aging (NIA)
Conditions Preclinical Alzheimer's Disease, Early Preclinical Alzheimer's Disease
Enrollment 1,400 participants
Start Date 2020-07-14
Primary Completion 2028-12-21 (estimated)
Study Completion 2031-01-16 (estimated)
Updated on ClinicalTrials.gov 2026-06-04