Since the approval of four cholinesterase inhibitors in the 1990s and memantine in 2003, there have been no new treatments for Alzheimer's disease, a condition that currently affects more than 35 million people worldwide. Against this backdrop, Paul Aisen of the University of California, San Diego, opened the 4th International Conference on Clinical Trials on Alzheimer's Disease (CTAD) on 3 November 2011 in San Diego, California. Aisen's keynote address, now available on Alzforum tracks the evolution of Alzheimer's disease trials from the first trials in 1986, to the above-mentioned approvals, to the many subsequent failures. Aisen plots a new phase forward, with researchers having a better handle on how to tackle the disease. Along with Aisen's talk, Alzforum provides highlights of ongoing trials that were presented at CTAD.
Aisen, who heads the Alzheimer's Disease Cooperative Study (ADCS), a major academic sponsor of Alzheimer's trials, said researchers have learned hard lessons about how to conduct such trials. For one thing, there is a growing consensus in the field that interventions are needed in the earliest stages of the disease, before the brain has suffered significant damage. But how? Some trials have already been conducted in people who have mild cognitive impairment (MCI)—in other words, who have some memory problems but no dementia. But these trials have all failed, and Aisen explains why. Since then, researchers have refined tools to identify those people with MCI who will most likely progress to Alzheimer's.
But beyond that mildly symptomatic stage, Aisen argued that researchers should go after the disease even before any clinical symptoms appear. Recent studies have revealed that there are signs of Alzheimer's, which can be detected by measuring certain proteins or taking images of the brain, even before people or their doctors know anything is wrong. "We would like to move to the point where function is intact and there are no clinical symptoms," said Aisen. "We think this represents a very promising population for clinically meaningful treatment." Aisen and other researchers are currently planning such a trial.
Other stories from the CTAD meeting include the results of two trials, one of a medical food and one of an agent that targets the protein clumps that gum up the brains of Alzheimer's patients; an upcoming feature that describes new technologies for conducting clinical trials in the comfort of people's homes; and another on a possible new method for detecting Alzheimer's disease by taking electrical recordings on people's scalps.
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