An experimental drug that failed to stop mental decline in Alzheimer's patients also signaled potential benefit that suggests it might help if given earlier, fuller results of two major studies show.
Some patients on the drug had stable levels of brain plaque and less evidence of nerve damage, compared with others who were given a dummy treatment, researchers reported yesterday.
The drug bapineuzumab is made by Pfizer Inc. and Johnson & Johnson. The new results suggest it might work if given sooner, before so much damage and memory loss have occurred that it might not be possible to reverse, experts say.
"We're very disappointed that we were not able to come up with a treatment to provide to our dementia patients in the near term," said Dr. Reisa Sperling, director of the Alzheimer's center at Brigham and Women's Hospital in Boston and leader of one of the studies.
But brain imaging and spinal fluid tests are "very encouraging" and suggest the drug was "doing something to the biology of the disease," she said.
Of people with mild cognitive impairment, about 15 to 20 percent a year will develop Alzheimer's disease. About 35 million people worldwide have dementia. In the United States, about 5 million have Alzheimer's.
Current medicines such as Aricept and Namenda ease symptoms just temporarily. There is no known cure.
Sperling's study involved people with a gene that raises the risk of developing the disease. Dr. Stephen Salloway, a neurologist at Brown Medical School in Providence, R.I., led the other study of people without the gene. Both have consulted for the companies that make the drug and presented results yesterday at a neurology conference in Stockholm.