CompletedPhase 2Results posted

Safety and Efficacy Study of AC-3933 in Adults With Mild to Moderate Alzheimer's Disease

A Phase II, Double-Blind, Randomized, Placebo-Controlled, Parallel-Group, Dose-Ranging Study Assessing the Efficacy and Safety of AC-3933 Tablets Twice Daily in Adults With Mild to Moderate Alzheimer's Disease

Lead sponsor

Sumitomo Pharma America, Inc.

Asset

AC-3933

Listed sites

Recruiting sites

Enrollment

171

actual

Study population

Alzheimer’s disease

Key I/E criteria

•mild-to-moderate AD•Study partner/caregiver required

Primary endpoint

•ADAS-Cog

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 IDAC-3933-271

NCT IDNCT00359944

Timeline

Milestones

Study start2006-02 (month precision)

Study first posted2006-08-03estimated

Primary completion2008-09actual (month precision)

Study completion2008-09actual (month precision)

Last update posted2013-07-02estimated

Results first posted2013-07-02estimated

Assets

Drug assets

AC-3933

Study populations

Who this study enrolls

Alzheimer’s disease

Eligibility

Who can enroll

Minimum age55 Years

SexAll

Healthy volunteersNot accepted

Inclusion criteria

•Mild to moderate Alzheimer's Disease

•Male or female 55 years or older

•Living with caregiver

•Read, understand and speak English

Exclusion criteria

•Need to drive during the study

•Treatment with acetylcholinesterase inhibitors or NMDA antagonist, such as Aricept or Namenda, within 2 weeks of check-up and during the study

•Frequent Smoker

•Frequent Consumer of Caffeine

Endpoints (6)

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

Global cognition

Function / daily living

Other clinical outcomes

Global cognition

2 endpoints

Primary/protocol endpoint

Total Score of Alzheimer's Disease Assessment Scale - Cognition Subscale (ADAS-COG)From Best Total Score (0) to Worst Total Score (70)

Time frame:Baseline to 16 weeks

ADAS-Cog

change from baseline, improvement

Primary/registry result

Total Score of Alzheimer's Disease Assessment Scale - Cognition Subscale (ADAS-COG)From Best Total Score (0) to Worst Total Score (70)

Time frame:Baseline to 16 weeks

ADAS-Cog

change from baseline, improvement

Posted result

Group	Value (mean), units on a scale	Standard deviation
AC-3933, 5 mgn=43 Participants	-1.3	0.84
AC-3933, 20 mgn=40 Participants	-2.9	0.88
Placebon=49 Participants	-1.5	0.78

Function / daily living

2 endpoints

Secondary/protocol endpoint

Disability Assessment for Dementia (DAD)

Time frame:Baseline to 16 Weeks

change from baseline, improvement

Secondary/registry result

Disability Assessment for Dementia (DAD)

Time frame:Baseline to 16 Weeks

change from baseline, improvement

Posted result

Group	Value (mean), units on a scale	Standard deviation
AC-3933, 5 mgn=43 Participants	-2.7	1.89
AC-3933, 20 mgn=40 Participants	4.0	2.10
Placebon=49 Participants	4.2	1.80

Other clinical outcomes

2 endpoints

Secondary/protocol endpoint

Clinicians Interview Based Impression of Change (CIBIC)-Plus

Time frame:Baseline to 16 weeks

descriptive

Secondary/registry result

Clinicians Interview Based Impression of Change (CIBIC)-Plus

Time frame:Baseline to 16 weeks

descriptive

Posted result

Group	Value (mean), units on a scale	Standard deviation
AC-3933, 5 mgn=43 Participants	4.1	0.97
AC-3933, 20 mgn=40 Participants	3.9	1.11
Placebon=49 Participants	3.9	0.91

Provenance

Sources

Trial identity, design, statusClinicalTrials.gov API v2

Snapshot dateJuly 21, 2026

Endpoint classificationDelfa ADRD endpoint taxonomy

Results tableClinicalTrials.gov results section

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.