We’re about to find out if there will be a way anytime soon to slow the course of Alzheimer’s disease. Results are due within a month or so from key studies of two drugs that aim to clear the sticky plaque gumming up patients’ brains.
A pivotal study of a third drug will end later this year, and results from a small, early test of it will be reported next week at an Alzheimer’s conference in Vancouver, British Columbia.
These three treatments are practically the “last men standing” in late-stage trials, after more than a decade of failed efforts to develop a drug to halt the mind-robbing disease. Current medicines such as Aricept and Namenda just temporarily ease symptoms. There is no known cure.
Experts say that if these fail, drug companies may pull out of the field in frustration, leaving little hope for the millions of people with the disease. An estimated 35 million people worldwide have dementia, which includes Alzheimer’s. In the U.S., experts say about 5 million have Alzheimer’s.
The three treatments being tested are not even drugs in the traditional, chemical sense. They are antibodies — proteins made by the immune system that promote clearance of amyloid, the stuff that forms the plaque.
It’s a strategy with a checkered history, and scientists aren’t even sure that amyloid causes Alzheimer’s or that removing it will do any good in people who already have symptoms. But there are some hopeful signs they may be on the right track.
“Everybody in the field is probably holding their breath that there is something positive to come out of these trials,” said Dr. Ronald Petersen, director of the Mayo Clinic’s Alzheimer’s Disease Research Center.
“It may not be a home run” in terms of improving memory and cognition, but if brain imaging or spinal fluid tests show the drugs are hitting their target, “they will be regarded as successes,” he said.
William Thies, scientific director of the Alzheimer’s Association, agreed.
Even if there is just a small effect, “that would be a huge finding because that would let you know you had a drug that worked,” he said. It then could be tried as a preventive medicine or given earlier in the course of the disease when it may have more impact.
The three drugs and their developers are:
• Bapineuzumab (bap-ih-NOOZ-uh-mab), by Pfizer Inc. and Johnson & Johnson’s Janssen Alzheimer Immunotherapy unit.
• Solanezumab (sol-ah-NAYZ-uh-mab), by Eli Lilly & Co.
• Gammagard, by Baxter International Inc.
All are given as periodic intravenous infusions; some companies are trying to reformulate them so they could be given as shots. If a major study shows that one of the drugs works, there will be a huge effort to make it more convenient and practical, Thies predicted.