Developments in Brief : Alzheimer’s Treatment Disappoints Doctors
A widely publicized experimental treatment for Alzheimer’s disease that involved implanting drug pumps is proving to be a disappointment, but better medications may revive it, researchers say.
The treatment gained widespread publicity in 1984 with an encouraging study that involved a drug called bethanechol chloride, which was fed into the brain by the surgically implanted pumps.
Two new studies of that drug show too little improvement, however, to justify the treatment’s risks, researchers say.
“I would be very pessimistic that bethanechol is going to have any future for treating Alzheimer’s disease,” said Dr. Robert Harbaugh of the Dartmouth-Hitchcock Medical Center in Hanover, N.H. “What we’re working on now is to try to come up with a much more appropriate drug for infusion.” He spoke in New York last week at a conference on implanted drug pumps, sponsored by the New York Academy of Sciences.
Alzheimer’s disease afflicts an estimated 2.5 million American adults and kills more than 100,000 every year. It is a progressive, irreversible disorder that causes gradual memory loss, disorientation, personality change and loss of language skills.
Harbaugh was an investigator in the 1984 bethanechol study, which involved four patients. Members of the patients’ families said they noticed that the drug improved Alzheimer’s symptoms. But Harbaugh said that those assessments may have been biased by psychological cues given unintentionally by investigators.
His new study, designed to eliminate that possibility, involved 12 patients. A pump about the size of a hockey puck was implanted into the abdomen, and a tube leading from it was inserted into the brain.
Each patient got bethanechol for three months and an inert saline solution for another three months. Researchers tested each patient during both periods for comparison.
The drug produced some improvement in performance on an overall test that considers such abilities as orientation, language, short-term memory and attention, but more specific tests for short-term memory, language and other abilities failed to show any difference, Harbaugh said. “There is improvement on some of the functions with the drug infusion, but realistically not enough improvement to make this a viable treatment.”
Dr. Robert Wilson of Rush Medical College in Chicago found similarly disappointing results in 10 other Alzheimer’s patients. He said bethanechol produced no improvement in memory or other mental abilities and only slight improvement in such behavioral disturbances as agitation and delusions.
