http://www.sciencemag.org/news/2021/06/alzheimer-s-drug-approved-despite-doubts-about-effectiveness

The antibody aducanumab today became the first new Alzheimer’s disease drug approved since 2003. In a controversial decision that shocked some experts, the U.S. Food and Drug Administration (FDA) overruled a group of advisers to conclude that the drug, developed by Biogen, deserved market approval. The decision came despite thin and conflicting evidence from two large clinical trials about the drug’s ability to slow patients’ cognitive decline.

In announcing the decision, FDA acknowledged those studies of patients with early stage disease “left residual uncertainties regarding clinical benefit.” But it opted to approve aducanumab, marketed as Aduhelm, based on strong evidence that it clears a toxic form of the protein beta amyloid, which accumulates in the brains of people with Alzheimer’s and is thought to drive neuronal damage. Reduction of these plaques is “reasonably likely to predict important benefits to patients,” the agency said.