ALADDIN Study - Phase III: Antigonadotropin-Leuprolide in Alzheimer's Disease Drug INvestigation (VP-AD-301)

Inclusion Criteria: * 60 years of age or older * Diagnosis of probable mild-to-moderate Alzheimer's Disease * On a stable dose of an acetylcholinesterase inhibitor (including, but not limited to: donepezil, galantamine, rivastigmine, and tacrine) for at least 120 days prior to baseline and will likely remain on the drug throughout the trial; all participants must be on acetylcholinesterase inhibitors * No other significant or interfering medical conditions Exclusion Criteria: * Significant neurological disease affecting the brain or psychiatric disease other than AD, such as current untreated major depression, schizophrenia, epilepsy, Parkinson's disease, Creutzfeldt-Jakob's disease, or clinical episode of stroke * Laboratory or clinical signs of untreated, clinically significant abnormal thyroid function, in the Investigator's opinion * Received other investigational drugs within 30 days or 5 half-lives prior to baseline, whichever is longer * Taking other medications, with the exception of estrogen, known to affect serum gonadotropin (Gn) concentrations, including but not limited to goserelin, danazol, or leuprolide * Other exclusion criteria exist--eligibility can be assessed by the trial site