CompletedPhase 1

Evaluation of E2609 in Subjects With Mild Cognitive Impairment or Mild Dementia Due to Alzheimer's Disease (Study: E2609-A001-101 Amendment 02)

A Randomized, Double-blind, Placebo-controlled Study to Evaluate the Safety, Tolerability, Pharmacokinetics, and Pharmacodynamics of Single Oral Doses of E2609 in Subjects With Mild Cognitive Impairment or Mild Dementia Due to Alzheimer's Disease

Lead sponsor

Eisai Inc.

Asset

Elenbecestat

Listed sites

Recruiting sites

Enrollment

actual

Study population

Alzheimer’s disease, MCI / preclinical Alzheimer’s

Key I/E criteria

•Alzheimer's disease•Amyloid biomarker required

Primary endpoint

•Cerebrospinal fluid amyloid-beta levels

Footprint

Where this trial recruits

Site locations as reported to ClinicalTrials.gov. Site count is not enrollment count; per-site enrollment is not available from source.

Identifiers

Registered as

Org study IDE2609-A001-101

NCT IDNCT01600859

Timeline

Milestones

Study first posted2012-05-17estimated

Study start2012-07 (month precision)

Primary completion2013-09actual (month precision)

Study completion2013-10actual (month precision)

Last update posted2016-12-30estimated

Assets

Drug assets

Elenbecestat

Study populations

Who this study enrolls

Alzheimer’s diseaseMCI / preclinical Alzheimer’s

Eligibility

Who can enroll

Minimum age50 Years

Maximum age85 Years

SexAll

Healthy volunteersNot accepted

Inclusion criteria

•Meets the current cognitive classification of MCI or mild dementia due to AD pathology (all subjects having a "positive" biomarker for amyloid β) as defined by the National Institute on Aging - Alzheimer's Association (NIA-AA) research criteria

•Aged 50 to 85 years, inclusive at time of consent

Exclusion criteria

•Currently has any neurological condition other than AD (Alzheimer's disease)-related that could be contributing to the subject's cognitive impairment

•Significant pathological findings on brain MRI at Screening, including but not limited to multiple microhemorrhages

•Any psychiatric diagnosis or symptoms, e.g., hallucinations, major depression,anxiety or delusions that in the Investigator's opinion could interfere with assessment of cognition or confound the diagnosis of MCI or mild dementia due to AD in the subject.

•A lifetime history of cerebrovascular events or non-vasovagal related loss of consciousness within the last 10 years

•Any other abnormality of the ECG at Screening and/or Baseline (including QRS > 110 ms, abnormal electrical axis, PR interval > 220 ms and conduction abnormalities) considered clinically significant by the investigator

•History of cardiac arrhythmias, ischemic heart disease or cerebrovascular disease

•Lower spinal malformation on physical or lumbar spine radiography, local spinal infection, or other abnormality, including but not limited to obesity, that would prevent LP or insertion of an indwelling catheter for CSF sampling

•Any history of seizure disorder, symptomatic seizures (not including a history of simple febrile seizures in childhood) or any past or present medical condition which, in the opinion of the investigator has the potential to reduce seizure threshold (e.g., history of head trauma or concussion, previous alcohol abuse, substance abuse).

Endpoints (2)

What's being measured

Protocol endpoints and posted registry outcome measures, grouped into outcome categories. Composite endpoints show their component event types. Standard codes (LOINC, SNOMED CT) are shown where available.

Coverage by outcome category

Amyloid biomarkers

Safety / tolerability / PK

Amyloid biomarkers

1 endpoint

Primary/protocol endpoint

Percent change from baseline in cerebrospinal fluid amyloid-beta levels

Time frame:baseline to 36 hours post-dose

percent change from baseline, improvement

Safety / tolerability / PK

1 endpoint

Secondary/protocol endpoint

Incidence of adverse events

Time frame:8 days

event count, event

Provenance

Sources

Trial identity, design, statusClinicalTrials.gov API v2

Snapshot dateJuly 21, 2026

Endpoint classificationDelfa ADRD endpoint taxonomy

Results tableno registry results posted yet

Trial facts come from public ClinicalTrials.gov records. Endpoint categories are Delfa's classification of those records, not a ClinicalTrials.gov field. All figures reflect the July 21, 2026 snapshot.