Experimental drug promising for Alzheimer's

The study represents the first time that the drug, called memantine, was tested among persons with advanced Alzheimer's disease, said Dr. Barry Reisberg, of New York University School of Medicine, in an interview with Reuters Health.

The 252 volunteers in the study all had what is called stage 6 disease, which is a stage that typically occurs about 3.5 years after initial diagnosis, Reisberg said. At this point, the patient is "still at home but is now having some difficulty with tasks such as dressing and bathing," he said. Patients are usually the "most excitable and when the disease burden is most apparent for both patients and families." For that reason it is particularly useful to have a drug that can help slow the progression of the memory-robbing illness.

Reisberg said memantine is currently approved for use in Germany where "it is used to treat what is called a general dementia syndrome." The drug works on a type of messaging system in the brain called NMDA receptors. He said that this receptor system "is probably closest to what we call memory." Other Alzheimer's drugs work on another brain messaging system called the cholinergic system. "Memantine is the first drug to target the NMDA system," he said.

Thirty centres throughout the United States participated in the study and patients were assigned to receive either two 10-milligram doses of memantine a day or a placebo (inactive drug) for 28 weeks. At the end of the study period, the patients who received memantine showed less memory loss and had greater ability to function compared with the patients taking the placebo, he said.

"And while all the patients in both (groups) declined over the study period, the decline in the (memantine-treated group) was less severe," he said.