Why are drug trials in Alzheimer's disease failing?

摘要

You suggest several reasons why trials in Alzheimer's disease are failing (Aug 28, p 658), but you do not consider an obvious one: that the hypothesis on which most Alzheimer's trials are based might not be valid. If a scientist does several experiments on the basis of a hypothesis and they all fail, he will abandon the hypothesis. Why are we so reluctant to do this in medicine? The dominant hypothesis in the field is the amyloid hypothesis and almost all trials of potential disease-modifying drugs are based on manipulation of beta amyloid. In the recently abandoned semagacestat trial, some patients on the drug got worse-ie, the drug, which was designed to inhibit formation of beta amyloid, seemed to speed up cognitive decline.