A drug that quashes the activity of a key brain chemical is the first effective treatment for patients in the later stages of Alzheimer’s disease, according to the results of a large multi-center clinical study published in the April 3 issue of the New England Journal of Medicine. The drug, memantine, slows the mental and physical deterioration of patients with moderate to severe Alzheimer’s disease, according to Barry Reisberg, M.D., Professor of Psychiatry at NYU School of Medicine, who led the study. “These patients seem to be declining much less, about half as much as ordinarily expected, over a six-month period,” says Dr. Reisberg. “This medication will slow down the otherwise inexorable progress of this disease, and it is remarkably free of side effects. These are very impressive results. It looks like this drug really will have an impact on this disease,” he says.