July 17, 2008 — -- A pill once used as an antihistamine in Russia has shown a slight but unique promise for treating Alzheimer's disease and is now on a fast track to drug studies in the United States.
The drug, called Dimebon, appeared to slow memory loss in patients with mild to moderate Alzheimer's disease. But, unlike current Alzheimer's therapies, Dimebon also slightly improved memory. In another first, Dimebon's effect continued for more than a year, while current Alzheimer's treatments are known to peak at three or six months and then begin to lose their effects.
Yet the results from the study of 155 patients in Russia have left many Alzheimer's experts only cautiously optimistic until larger, longer studies are completed under the Food and Drug Administration.
"The Alzheimer's community has been here before with other drugs only to be disappointed," said Dr. Lon S. Schneider, professor of psychiatry and behavioral sciences at the University of Southern California Keck School of Medicine in Los Angeles. Schneider noted the same Dimebon results that appear in this week's medical journal, Lancet, also were released to scientists a year ago.
"There's not much to do except wait for the Phase III trial to be completed," Schneider said.
The race to find a good Alzheimer's treatment has been full of high hopes and devastating failures. At present, there is nothing to cure or stop Alzheimer's. In the current issue of Lancet, doctors also report that a once-promising vaccine shown to clear plaque in the brain associated with Alzheimer's has had little effect on the symptoms of memory loss.
Still, an American doctor who conducted the Russian study was heartened by the preliminary results. Patients showed improvements across five measures of mental, emotional and physical abilities. The side effects included dry mouth and reported depressed moods.
Participants in the study, half on placebo and half on Dimebon, were given two mental and memory tests, questioned about everyday skills such as dressing, asked about their anxiety and finally were interviewed by a separate doctor in a "clinician's global measure."