The Constellation Study is a clinical research study to test whether dimebon (latrepirdine) safely and effectively improves cognition (thinking and awareness), the ability to care for oneself, daily functioning, behavior, and quality of life in subjects with moderate to severe Alzheimer's disease who are already taking memantine.

Dimebon (latrepirdine) is an investigational oral medication being tested for Alzheimer's disease and Huntington disease. Dimebon has a unique mechanism of action, distinct from currently available treatments.