If you could invest $56 billion each year in improving health care for older adults, how would you spend it? On a hugely expensive medication with questionable efficacy—or something else? This isn’t an abstract question. Aduhelm, a new Alzheimer’s drug approved by the Food and Drug Administration (FDA) last month, could be prescribed to 1 million to 2 million patients per year, even if conservative criteria were used, according to Biogen and Eisai, the companies behind the drug. The total annual price tag would come to $56 billion if the average list price, $56,000, is applied to the lower end of the companies’ estimate. That’s a huge sum by any measure—more than the annual budget for the National Institutes of Health, which came in at almost $43 billion this year. Yet there’s considerable uncertainty about Aduhelm’s clinical benefits, fueling controversy over its approval. The FDA has acknowledged it’s not clear whether …