July 30, 2008
Experimental Drug Shows Promise at Stopping Alzheimer’s
By Mary Brophy Marcus
Alzheimer's researchers from Scotland announced on Tuesday that for the first time they have developed a drug that can halt cognitive decline in patients with mild and moderate Alzheimer's disease.
In the largest Phase II clinical trial of its kind, study author Claude Wischik, professor at the University of Aberdeen in the U.K. and executive chairman of TauRx Therapeutics, said that TauRx's drug methylthioninium chloride (MTC) was successful at halting the symptoms of Alzheimer's disease over a 50-week period. He presented his findings at the International Conference on Alzheimer's Disease meeting in Chicago.
Previous research has shown that a buildup of abnormal nerve fibers in the brain, made up of a protein called tau, is linked to memory loss in Alzheimer's disease. Rember, the brand name of the drug, had been successful at melting tau tangles in lab tests and in animal studies, but this is the first time an anti-tau drug has demonstrated benefits in people with Alzheimer's disease.
In Wischik's study, 321 people with either mild or moderate Alzheimer's disease were given a placebo or one of three doses -- 30, 60 or 100 milligrams -- of MTC three times a day for up to 84 weeks. Imaging scans were taken at the beginning of the study and again at 24 weeks. Patients' cognitive abilities were measured at 24, 50 and 84 weeks.
At 24 weeks, there was a decline in disease progression in only the patients with moderate Alzheimer's who were taking 60-mg capsules. But by 50 weeks, patients with mild and moderate Alzheimer's taking the medium and highest doses of the drug also saw a benefit, according to the researchers.
Wischik says the drug appeared to be reasonably well tolerated.
"I am not surprised by the results," Wischik says. "I think we've done it. We have proved the principle."
But some of Wischik's peers say it's too early to make such claims. "The first gut reaction is that this is kind of an overpromise. Anytime you have a name strongly suggesting efficacy, there is some skepticism," says Murali Doraiswamy, an Alzheimer's disease expert from Duke University Medical Center in Durham, N.C. "But these early findings are reason for cautious optimism."
Wischik says he is swimming against the research tide. "The main story in town for the last 20 years has been attacking amyloid plaque. A lot of people have said it's too late to treat the tangles, but that's bunkum," he says. Amyloid proteins form plaque outside brain cells, whereas tau proteins develop inside nerve cells.
A drug with multiple targets may be the answer, says Scott Turner, incoming director of the memory disorders program at Georgetown University Medical Center. "I think we may ultimately be treating with a drug cocktail that includes both anti-tau and anti-amyloid properties," he says. (c) Copyright 2008 USA TODAY, a division of Gannett Co. Inc. <>>