Drug Slows Alzheimer's Progression

It shows benefits for up to one year, new study finds

MONDAY, Jan. 9, 2006 (HealthDay News) -- A drug approved to treat moderate to severe forms of Alzheimer's disease appears to slow progression of the illness by nearly 50 percent for up to one year, a new study found.

The discovery involving the drug memantine (Namenda) builds on previous research that found the medication benefited Alzheimer's patients for up to six months.

In 2003, the U.S. Food and Drug Administration approved the use of Namenda for moderate to severe Alzheimer's, making it the only drug OK'd for such use. The approval followed a 28-week study of 252 patients, randomly selected to receive either the drug or a placebo, that showed the drug could slow the progression of Alzheimer's for up to six months.

"In 2003, we showed that a new medication that works by a novel system was effective in the moderate to severe stages of Alzheimer's disease," said lead researcher Dr. Barry Reisberg, a professor of psychiatry at New York University School of Medicine.

"We also found that the medication was remarkably safe. Today, millions of patients around the world are taking memantine based on our initial findings," added Reisberg, who is also clinical director of the university's Silberstein Aging and Dementia Research Center.

The new study, also led by Reisberg, showed Namenda benefited the same group of patients studied during the first trial for an additional six months.

The report appears in the January issue of the Archives of Neurology.

For the new trial, all patients who had received a placebo in the first trial of Namenda were given the active drug. The study enrolled 175 patients, 80 of whom had received the placebo the first time around. The remaining patients continued to receive the drug.

Reisberg and his colleagues evaluated the patients using a variety of tests that measured cognitive and functional abilities and behavior. The results showed a significantly slower rate of Alzheimer's progression among those patients who had been receiving a placebo and were now receiving Namenda, compared with their previous rate of decline.

"The effects that we saw over the initial six-month study seem to be maintained over one year," Reisberg said.

Although the drug is the only one approved for use by patients with severe Alzheimer's, Reisberg thinks Namenda might benefit patients in the early stages of the disease.

"There is a medication that is effective, and remains effective in slowing the progression of Alzheimer's disease," Reisberg said. "We finally have a medication to treat the condition that is effective not only over the short term but over the long term."

One expert called the study results promising.

"The good news is that the drug's benefit, albeit modest, lasts longer than previously documented," said Dr. Sam Gandy, director of the Farber Institute for Neurosciences at Thomas Jefferson University in Philadelphia.

"One wonders whether the drug might be showing some disease-modifying properties that were not seen with shorter-term uses," he added. "More basic and clinical work will need to be done before one can draw this conclusion, but more investigation is warranted."

Another expert, William Thies, vice president for medical and scientific affairs at the Alzheimer's Association, agreed that the study results hold promise, but they don't end the search for a truly effective Alzheimer's treatment.

"This drug is useful," Thies said. "Its effects are definite, but relatively modest."

"The results of this trial are typical of some of the other medications we have for Alzheimer's disease," he said. And whether Namenda gives an additional benefit over other medications is still an open question, he noted.

"So, it might be that the next generation of drugs will extend the usefulness of drugs like Namenda," Thies said.

In other research, scientists from the University of Pittsburgh School of Medicine and the University of California, Los Angeles reported that mild cognitive impairment (MCI) -- a transitional stage between normal functioning and Alzheimer's disease -- exists in two different forms.

Using a new imaging technique that creates three-dimensional maps of the brain, the researchers determined specific areas that had degenerated in people with MCI. Depending on the person's symptoms, more tissue was lost in the hippocampus, a brain area critical for memory and one of the earliest to change in Alzheimer's disease, indicating two different paths of progression to Alzheimer's disease. The finding could lead to better diagnosis and treatment of patients with MCI, perhaps delaying or preventing the onset of dementia, the researchers said.

The findings appear in the same issue of the Archives of Neurology.

More information

Learn more about Alzheimer's disease from the Alzheimer's Association.

SOURCES: Barry Reisberg, M.D., professor, psychiatry, and clinical director, Silberstein Aging and Dementia Research Center, New York University School of Medicine, New York City; Sam Gandy, M.D., Ph.D., director, Farber Institute for Neurosciences, Thomas Jefferson University, Philadelphia; William Thies, Ph.D., vice president, medical and scientific affairs, Alzheimer's Association, Chicago; January 2006 Archives of Neurology
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