WASHINGTON, Jul 13 (Reuters Health) - An experimental drug that works on a
messaging system in the brain appears to slow the progression of advanced
Alzheimer's disease, according to study findings presented here on Wednesday at
the World Alzheimer Congress 2000.
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 centers 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.
Reisberg said Merz, the manufacturer of memantine, funded the study. More
extensive studies are needed before the drug will be approved for use in the US.
