We’ve talked a lot about clinical trials of several so-called disease modifying drugs for Alzheimer’s disease. These are medications designed to slow and perhaps even stop the progression of Alzheimer’s. Most of them so far have been drugs that remove beta-amyloid from the brain or block its production. Almost all of the clinical trials of these anti-amyloid drugs have been disappointing, although recently lecanemab received accelerated approval by the FDA based on effectiveness of removing amyloid plaques from the brain and a 27% slowing of cognitive decline, breathing a bit of new life into the amyloid hypothesis. Trials of drugs designed to remove tau, the abnormal protein in neurofibrillary tangles, have all failed so far. The development costs to design, test, produce, and conduct clinical trials on new drug candidates are enormous, costing hundreds of millions if not billions of dollars. A parallel effort is under way to find out if some drugs already in use for other disorders might have a benefit in Alzheimer’s disease.