TUESDAY, Jan. 20, 2004 (HealthDayNews) -- When it comes to treating Alzheimer's disease, two drugs may be better than one.
A new study appearing in the Jan. 21 issue of the Journal of the American Medical Association found the combination of the recently approved drug, memantine, with an older medication, donepezil, slows the progression of cognitive decline in people with moderate to severe Alzheimer's disease.
"This is the first medicine in a brand new class. We now have a second treatment option that can buy people time, and in some cases improve their cognitive ability," says study author Dr. Pierre Tariot, a professor of psychiatry, medicine and neurology at the University of Rochester Medical Center in Rochester, N.Y. But, he adds, this medication is not a cure.
Another new Alzheimer's study finds that a state-of-the-art brain scan has detected, for the first time, a key protein in the brain closely associated with Alzheimer's. Having such a scan can help diagnose the disease much earlier. Typically, Alzheimer's is diagnosed through characteristic symptoms, but is confirmed only after an autopsy.
Alzheimer's disease is a degenerative disease of the brain that causes memory loss, difficulty learning, loss of language skills, difficulty performing routine tasks, disorientation and personality changes. More than 4 million Americans currently have the disease, according to the Alzheimer's Association. During the next 50 years, it's estimated that more than 11 million people in the United States will develop the disease.
Treatment options for the disorder are limited. Until recently, the only class of medications available to treat the memory problems of Alzheimer's was cholinesterase inhibitors, such as donepezil (Aricept), rivastigmine (Exelon) and galantamine (Reminyl). These drugs work by increasing the levels of a neurotransmitter in the brain called acetylcholine, which aids in memory and learning.
The U.S. Food and Drug Administration approved memantine (Namenda) in October 2003. Memantine works by regulating levels of glutamate, a neurotransmitter that also aids in learning and memory, because too much glutamate can be damaging.
Tariot and his colleagues gave 322 people with moderate to severe Alzheimer's disease either the memantine-donepezil combination or a placebo. The study participants were from 37 different areas across the United States, they were mostly white, and their average age was 75.
The researchers administered function tests at four, eight, 12, 18 and 24 weeks. One test is called the Severe Impairment Battery (SIB), and it measures cognitive dysfunction in people with Alzheimer's. Scores on this test range from 0 to 100. Another test the researchers administered was the Alzheimer's Disease Cooperative Study-Activities of Daily Living Inventory (ADCS-ADL), which measures how a person can perform daily tasks and scores range from 0 to 54.
At the end of the study, people in the drug combination group had increased nearly one point on the SIB scale, while those in the placebo group had dropped 2.5 points. On the ADCS-ADL scale, those receiving the combination treatment dropped two points compared to 3.4 points for the placebo group.
While the differences may not look large, Tariot says the group treated with memantine-donepezil performed statistically better than the placebo group. He adds that if your loved one has Alzheimer's, any improvement in cognitive function can offer some relief or hope.
He says the treatment was very well tolerated and, in fact, there were fewer side effects reported by the treatment group than the placebo group.
William Thies, vice president for medical and scientific affairs for the Alzheimer's Association, says the drug combination "had about the kind of effect we expected."
He says this study is a good start, and eventually the drug will likely be tested for use in people with mild Alzheimer's disease as well.
"There continues to be progress in the battle against Alzheimer's disease, and we will eventually beat this disease," Thies says. "We're just not done yet."
Another progressive move comes from the second new study, in which University of Pittsburgh researchers tested an amyloid-imaging positron emission tomography (PET) with a new tracer they dubbed Pittsburgh Compound-B. Amyloid is the protein that is deposited in the brains of Alzheimer's patients.
Though the study was small -- 16 patients with diagnosed mild Alzheimer's got the novel scan, and there were nine healthy control patients -- the researchers found a "robust" difference in the amount of amyloid present in the brains of the Alzheimer's patients.
Dr. John C. Morris, a neurologist at Washington University in St. Louis and a board member of the Alzheimer's Association, says the scanning study "has enormous implications."
The scans could be used to track the performance of drugs, vaccines and other therapies that break down amyloid or prevent it from forming, Morris says. The technology could also help diagnose Alzheimer's in living people and possibly predict who's likely to get the disease based on their brain chemistry.
"Those are all big ifs, but now we have the tool with these imaging molecules," he says.
More information
Learn more about the disease from the Alzheimer's Association, which also has a page on treatment options.
HealthDay reporter Adam Marcus also contributed to this report.
