On June 7th the U.S. Food and Drug Administration approved a new drug to treat early-stage Alzheimer’s disease. Or perhaps I should say a drug intended to treat early-stage Alzheimer’s was approved for any of the 6 million people with the disease. Presumably, nearly all those with Alzheimer’s – or their families – will demand this new drug whether they are likely to benefit. The drug, Aduhelm, is a monoclonal antibody. It targets a specific protein in the brain that is thought to form plaques in the brains of Alzheimer’s patients, causing brain cells to atrophy and die. Is this...