Dimebon Shines as Alzheimer's Therapy
Alzheimer's Stable With Dimebon; Alzheimer's Drug Rember Looks Good, Too
Samuel Gandy, MD, PhD, chairman of the Alzheimer's Association's Medical and Scientific Advisory Council, found the Dimebon data "very encouraging," but warns patients not to get their hopes up too high -- yet.
Although the Russian study included well-respected Alzheimer's researchers from the U.S., the study must be replicated by independent investigators in American and Western European settings. And it's not at all clear whether Dimebon alters the course of Alzheimer's disease or just makes symptoms better for a while.
"Dimebon does appear to preserve function at an improved state for quite a long time," Gandy tells WebMD. "But it is not clear this is anything more than a symptomatic drug -- and if it doesn't modify the disease, it will eventually wear off."
How does Dimebon work? Nobody knows for sure. There's evidence the drug affects mitochondria -- the power plants that energize cells -- fixing a defect that kills brain cells. That may be why the drug also seems to help patients with Huntington's disease.
"Improvements in mitochondrial health affect all cells," Hung says. "In our trial, we saw fewer adverse events in Dimebon patients than in control patients. So we are not only seeing beneficial effects, but the drug is better tolerated than placebo. That is a very attractive profile for patients."
Anti-Tangle Drug Rember
Plaque isn't the only thing that clogs the brains of people with Alzheimer's disease. There's also a buildup of fibrous tangles, made up of a protein called tau. These tangles appear in the brain before symptoms appear -- and the more tangles there are, the worse the disease gets.
TauRX Therapeutics of Singapore is developing a drug called Rember that dissolves tau tangles and prevents tau from forming new tangles.
In a 321-patient trial in the U.K. and in Singapore, patients with mild-to-moderate Alzheimer's disease were treated with Rember or placebo.
After 19 months of treatment, Rember-treated patients had no decline in cognitive function. Brain scans suggested the drug reduced tangle density in parts of the brain critical for memory, according to a conference report by Claude Wischik, chairman of TauRx Therapeutics and professor of psychiatric gerontology at the University of Aberdeen, Scotland.