Description: The A4 study is investigating a new drug (solanezumab) that may reduce the amount of a protein known as "amyloid" or "beta amyloid" that forms plaques in the brain. Scientists believe that the buildup of amyloid in the brain may play a key role in the eventual development of Alzheimer's disease. The primary objective of this study is to test the hypothesis that solanezumab will slow cognitive decline compared with placebo in subjects at high risk for developing Alzheimer's disease. There are two phases in this study: Screening (≤ 3 months) and Treatment (3 years). During the screening phase, participants will learn whether they have an "elevated" or "not elevated" level of brain amyloid. Only individuals with "elevated" amyloid on the PET scan will be eligible to continue in the study. During the treatment phase, participants will be given an intravenous (IV) infusion every month for three years. Subjects have a 50/50 chance of receiving the active drug versus placebo. The study is a double-blind study, meaning that neither the patient nor the study staff will know who is receiving the active drug or placebo until the end of the study.

Eligibility: Researchers are looking for people who are healthy men or women with normal thinking and memory function. They must be fluent in English, between 65 to 85 years old, and have a partner who is willing to participate as a source of information about their daily function.

For further information, please contact Gerard Duncan at (713) 798-5325 or