The U.S. Food and Drug Administration gave the green light to Biogen’s Alzheimer’s disease drug, marketed as Aduhelm, on Monday. But the first Alzheimer’s medication to receive approval in almost two decades doesn’t come without controversy.

Why is it controversial? Research showed the treatment didn’t reverse the progression of the disease and only slowed patients’ cognitive decline slightly. Critics say that’s not enough evidence to bring the drug to market, especially given its price tag of up to $50,000 a year.

FDA regulators admitted “residual uncertainties” surround the drug but said it was “reasonably likely” to benefit patients with Alzheimer’s. The medicine targets harmful clumps of plaque in the brain that are thought to play a role in the disease. But doctors still don’t know what causes Alzheimer’s to develop.

An independent panel of experts, which the FDA itself convened, rejected the drug last year and warned that approval could cause potential damage. 

“Alzheimer’s treatment is a huge, urgent, unmet need,” panelist Dr. Joel Perlmutter of Washington University School of Medicine told the Associated Press last November. “But if we approve something with data that is not strong we have the risk of delaying good, effective treatments.”

With reporting from J.C. Derrick

This story originally appeared in WORLD. © 2021, reprinted with permission. All rights reserved.