The amyloid hypothesis on trial
In early 2018, two high-profile clinical trials of drugs for Alzheimer’s disease ended in disappointment. The drugs joined a long list of potential treatments that have failed to deliver significant benefits in people. Their development was guided by an idea that has dominated research on Alzheimer’s disease for more than 25 years: the amyloid hypothesis, which is the assumption that accumulation of the peptide amyloid-β is the main cause of the condition. Researchers proposed that when amyloid-β clumps together to form deposits in the brain, it triggers neurodegenerative processes that lead to the loss of memory and cognitive ability that is observed in Alzheimer’s disease. Amyloid-β is therefore an obvious therapeutic target — if you can deal with the peptide, then you can treat the condition.