Conference Presentation

Eisai brings AHEAD 3-45 retention data to AAIC, not efficacy results

The Phase 3 prevention trial in preclinical Alzheimer's will show participant retention and engagement data at AAIC in July, with the amyloid-PET primary endpoint still years from readout.

By AppliedXLJuly 14, 2026Trial NCT04468659

Executive Summary

Eisai is using a major Alzheimer's conference to update on how a long-running prevention trial is being run, not on whether the drug is working.
The trial is testing a preventive hypothesis in people without symptoms, a use case no amyloid antibody has yet proven, and the answer is still years away.
The trial finished enrolling on schedule and has since run as a closed, ongoing study, which points to execution risk sitting on data maturity rather than recruitment.
The nearest comparable prevention effort targets the same biology from a different sponsor, meaning this trial's eventual result will inform how that program's own risk is read.

The presentation

Eisai said it will present findings on the Phase 3 AHEAD 3-45 study in preclinical Alzheimer's disease at AAIC 2026, running July 12 to 15 in London, as part of a broader slate of 52 abstracts on its Alzheimer's portfolio. The AHEAD 3-45 presentation will cover progress of the trial, including updates on participant retention and engagement, rather than clinical outcome data. The trial is registered as NCT04468659, a Phase 3, industry-sponsored study of lecanemab in adults age 55 to 80 with elevated or intermediate brain amyloid but no cognitive symptoms. Eisai+1

What the trial is built to answer

AHEAD 3-45 enrolled 1,400 participants across two sub-studies, A3 and A45, differentiated by amyloid burden at screening, and its registered primary outcome is change from baseline in amyloid PET standard uptake value ratio at Week 216. The trial completed enrollment in October 2024, with investigators reporting at a prior conference that switching to plasma biomarker (Abeta42/40 and p-tau217) screening cut amyloid PET screening failure from more than 70% to under 30%, an operational finding about trial conduct rather than a clinical result. No primary endpoint data at Week 216 have been reported. NCT04468659

Timeline and trial conduct

The trial's primary completion date has moved six times since 2022, swinging between 2027-05-28 and 2029-02-15 before settling at its current 2028-12-21 date, set in July 2024. Status moved from Recruiting to Active, not recruiting in January 2025, consistent with a trial that filled its enrollment target and is now following participants through the study's assessment schedule rather than still screening new ones. The registry shows no further primary completion date change since mid-2024, and the current AAIC presentation covers retention and engagement rather than a shift in that date. NCT04468659+1

The competitive frame

Lecanemab holds full FDA approval for symptomatic Alzheimer's disease under the brand LEQEMBI, along with approvals in Japan and the European Union, giving AHEAD 3-45 an approved-drug foundation rather than an unproven molecule. Within the amyloid-beta target class, the closest direct comparator testing the same prevention hypothesis is Eli Lilly's donanemab program, sharing the amyloid-beta target and monoclonal antibody modality; a subject-trial readout carries readthrough to how that program's own prevention-trial risk gets read. No other amyloid-beta protofibril-targeting trial in preclinical Alzheimer's disease has reached Phase 3, leaving AHEAD 3-45 and Lilly's TRAILBLAZER-ALZ 3 as the field's only advanced tests of amyloid removal before symptom onset.

This analysis was produced using AI-assisted reporting systems, AppliedXL data, and official public records. These systems undergo editorial review, quality checks, and regular audits by human experts. Errors may still occur, as with any automated system. Always consult the linked primary sources. Read our AI Editorial Policy.