After the failure of multiple drug trials the outlook for an Alzheimer's drug is bleak. This shouldn't be a surprise. We don't know the cause or even how to diagnose the disease.
Not all drug development needs to start from scratch. Sometimes researchers discover that a drug developed for one disease can be used for another. Here a cancer drug may show promise for dementia.
Many pieces leading to Alzheimer's disease have been identified. To put the pieces together, one scholar argues that the government should launch a Manhattan Project-scale effort to find a cure.