Three treatments for Alzheimer’s disease are undergoing late-stage trials. If none of these treatments can be considered a success once the trials are finished, Alzheimer’s researchers will need to consider starting over on another track in their quest to prevent or cure Alzheimer’s disease. Existing drugs for Alzheimer’s can slow the symptoms of Alzheimer’s for some people, but they don’t affect the underlying mechanism of the disease.
So far, the first of these late-stage trials has proven to be a failure. Pfizer Inc., said that Bapineuzumab, Pfizer's experimental Alzheimer's disease treatment “failed to prove effective in one of four late-stage trials in patients with mild to moderate forms of the memory-robbing disease. The drug failed to improve cognitive and life function, the primary goals of the trial, compared with patients taking placebos. Pfizer will continue to conduct the remaining tests to see how the treatment performs under different criteria.”
The remaining two treatments heading toward the finish line are Solanezumab by Eli Lilly & Co. and Gammagard, by Baxter International Inc.
According to an article on USNews.com, experts feel that even a small positive showing from a treatment would be helpful enough for research to continue.
Dr. Ronald Petersen, director of the Mayo Clinic's Alzheimer's Disease Research Center said, of the three drugs, “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.”
William Thies, scientific director of the Alzheimer's Association, agrees. He said that “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…It then could be tried as a preventive medicine or given earlier in the course of the disease when it may have more impact.”
There has been some success. Gammagard, also known as intravenous immunoglobulin, or IViG therapy, was in the news July 18, 2012, because a small study showed that the therapy halted the cognitive decline in some individuals with Alzheimer’s disease. This study had only 16 participants, however larger studies are underway.
Will one of these drugs or treatments show researchers a clear way forward? The studies are premised on the belief that Alzheimer’s disease is caused by Amyloids, which are insoluble fibrous protein aggregates that cause the plaque in the brain which is commonly associated with Alzheimer’s disease.
While the majority of Alzheimer’s research is aimed at stopping or reversing the development of the brain plaques caused by Amyloids, not all researchers are convinced that Amyloids are the correct target for their work. Some recent studies have shown that deep brain stimulation can be very effective in halting the progression of Alzheimer’s disease. This therapy hasn’t been tested on large numbers of people either, so large-scale results remain to be seen.