Alzheimer’s disease takes a long time to develop, which suggests that it may be possible to design drugs that work early in the disease process, to delay the start of symptoms. Over the past decade, researchers have been testing a number of such “disease-modifying” drugs that target the earliest biological changes in Alzheimer’s, reports the October 2007 issue of the Harvard Mental Health Letter.

None of the disease-modifying drugs now in development will cure Alzheimer’s. But a number of them are currently in phase III clinical trials, the last stage before the FDA will consider approving the drugs for sale. Media interest has already begun to intensify. In June, for example, the AARP Bulletin trumpeted on its cover: “Finally, new drugs offer real hope for reversing the disease.”

Two experts interviewed by the Mental Health Letter temper the optimism with caution. The experts note that questions remain whether these drugs will be effective enough to block Alzheimer’s or safe enough to be taken for a long time and with other medications.

A larger issue is whether the drugs aim at the right targets. The new disease-modifying drugs target early biological abnormalities, especially the sequence of events involved in the creation of amyloid plaques (a hallmark brain lesion in Alzheimer’s). Dr. Michael Miller, editor in chief of the Harvard Mental Health Letter,notes that although most of the research effort so far has focused on this stage, researchers are still developing their understanding of how Alzheimer’s develops. “Scientists are encouraged by their research into the details of the genetic and environmental causes of Alzheimer’s,” he says. “They look forward to identifying other interesting targets of treatment as the science evolves.”