Eligibility Criteria:
Inclusion Criteria:
1. Men and women age 55 to 85 years, inclusive.
2. Willing and able to provide informed consent.
3. Must have mild cognitive impairment (MCI) or mild AD with evidence of progression ("Mild-AD"), as defined by the following:
1. CDR-Global Score of 0.5 or 1.0, with CDR memory subscore of at least 0.5.
2. MMSE score ranging from 20 to 28, inclusive.
3. Positive biomarker for AD, as defined by a CSF Aβ1-42R below the threshold and phospho-tau above the threshold for the assay utilized in the study and assessed by the central laboratory.
4. Computed tomography (CT) or magnetic resonance imaging (MRI) findings within 2 years of Screening that are compatible with AD and no other pathologic processes that might potentially account for the subject's cognitive impairment.
5. If the subject is taking a single drug for AD (e.g., donepezil or other cholinesterase inhibitors or memantine; dual therapy is excluded), he/she has been on a stable dose for at least 2 months prior to baseline, and the dose must remain unchanged during the study unless required for management of adverse events (AEs).
6. Adequate visual and auditory abilities to perform all aspects of the cognitive and functional assessments.
7. Must have reliable informant or caregiver.
Exclusion Criteria:
1. Evidence that the primary basis for cognitive impairment is neurodegenerative disease other than AD, including, but not limited to, vascular dementia, dementia with Lewy bodies, and Parkinson's disease.
2. Suicidality, defined as active suicidal thoughts within 6 months before Screening or at Baseline, defined as answering yes to items 4 or 5 on the Columbia-Suicide Severity Rating Scale (C-SSRS), or history of suicide attempt in previous 2 years, or, in the Investigator's opinion, at serious risk of suicide.
3. History of major and active psychiatric disorder, moderate to severe depressive symptoms, and or other concurrent medical condition that, EIP-VX17-745-304, Version 1.0, 17 November, 2017 Page 7 of 46 EIP Pharma, LLC Confidential in the opinion of the Investigator, might compromise safety and/or compliance with study requirements.
4. Diagnosis of alcohol or drug abuse within the previous 2 years.
5. History of cancer within the last 5 years, except basal cell carcinoma, squamous skin carcinoma, prostate cancer or carcinoma in situ with no significant progression over the past 2 years.
6. Poorly controlled clinically significant medical illness.
7. History of serum B12 abnormality, anemia with hemoglobin ≤10 g/dL, thyroid function abnormality, electrolyte abnormality, or positive syphilis serology that have not been corrected and/or otherwise addressed.
8. History of epilepsy or unexplained seizure within the past 5 years.
9. Aspartate aminotransferase (AST) or alanine aminotransferase (ALT) \>3 × the upper limit of normal (ULN), total bilirubin \>2 × ULN, and/or International Normalized Ratio (INR) \>1.5
10. Known human immunodeficiency virus, hepatitis B, or active hepatitis C virus infection.
11. Subject participated in a study of an investigational drug less than 3 months or 5 half-lives of the investigation drug, whichever is longer, before enrollment in this study.