According to a new study, a drug frequently prescribed to treat people with mild Alzheimer's disease does not appear to be an effective therapy for many of these patients.
Results from the study shows that drug, memantine, is no better than a dummy pill when it comes to ameliorating disease symptoms, including the decline of mental abilities and also helping patients with moderate Alzheimer's, the researchers say. Sold under the brand Namenda by Forest Laboratories Inc and Germany's Merz Pharma, the drug had U.S. sales of about $1.2 billion last year.
Memantine is approved by the Food and Drug Administration to treat patients with moderate and severe Alzheimer's. It is also prescribed to those with mild forms of the disease. About 19 percent of U.S. patients with mild Alzheimer's disease take the drug, the researchers say. The drug is intended to improve cognitive functions and make it easier for patients to perform daily activities.
According to study researcher Dr. Lon Schneider, of the University of Southern California Keck School of Medicine in Los Angeles, some physicians may prescribe it, and some patients may take it, “under the hopes that it's better to treat with this drug now rather than it is to wait until somebody becomes severe and then treat them.” Schneider said this study should alert doctors who are treating mild and moderate Alzheimer's patients with memantine. Additional studies should be conducted looking at the effects of memantine on patients with mild disease, Schneider said. The study was published online Monday in the journal Archives of Neurology.
Schneider and his colleagues analyzed three studies that had randomly assigned patients to receive either memantine or a placebo. These studies included 431 patients with mild Alzheimer's and 697 patients with moderate Alzheimer's. The researchers were able to extract the information on patients with mild Alzheimer's disease and examine it separately. Mild Alzheimer’s patients on the drug fared no better than patients on the placebo in terms of improvement of symptoms and their ability to carry out daily activities. The drug had a small effect on those with moderate Alzheimer's disease when the researchers combined information from the three trials.
Experts have not yet called for a complete stoppage of the drug’s use though. “Physicians should become as educated as possible about the drugs and use them with their best judgment,” said William Thies, chief medical and scientific officer at the Alzheimer's Association, who was not involved in the study. “The success or lack of success is such a close call, and the effects are so small, I think a blanket recommendation is very hard to give at this point,” Thies said.
It is estimated that as many as 5 million Americans and 26 million all over the world have Alzheimer's disease, according to the Centers for Disease Control and Prevention. Patients are categorized as having mild, moderate or severe forms of the disease depending on how well they score on a test designed to assess mental abilities.
Thies notes patients can vary widely in their response to the drug. It's possible that some patients with mild Alzheimer's disease do improve significantly, but these positive effects are hidden because many other patients in the trial do not improve. “We don't have a good way of picking out who will respond ahead of time,” Thies said. He called for further studies to provide a better idea of which patients benefit most from the drug. Gary Kennedy, M.D., the director of geriatric psychiatry at Montefiore Medical Center, in New York City, says that while the new study will “make people more appropriately cautious,” it isn't likely to change doctors’ prescribing practices.
The trials were originally sponsored by Forest, but the new analysis was funded by grants from the National Institutes of Health and other non-industry sources. Dr. Lon Schneider Schneider has served as a consultant for Forest.
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