The new Alzheimer’s result is why we should demand good clinical trials

The announcement Tuesday night from Eisai and Biogen that their experimental medicine, lecanemab, reduced Alzheimer’s patients’ decline as measured by a clinical questionnaire is one of the biggest – and potentially happiest – shocks in the recent history of medicine.

It’s a shock because Biogen had so bungled the launch of their previous Alzheimer’s drug, Aduhelm, with failed clinical trials, a tortuous path to approval, and a wholesale rejection by Medicare and by the market. Wall Street analysts, who advise investors on what to buy, were not expecting success.