This image provided by Biogen on Monday, June 7, 2021 shows a vial and packaging for the drug Aduhelm. Congressional investigators have asked the maker of an Alzheimer's drug to turn over information about how the company developed and priced the medication. The letter Monday, July 12, 2021 to Biogen is the opening salvo in a previously announced investigation into Aduhelm, an expensive and unproven therapy that has sparked scrutiny since winning U.S. approval last month.

WASHINGTON — Medicare on Monday launched a formal process to decide whether to cover Aduhelm, the new Alzheimer’s drug whose $56,000-a-year price tag and unproven benefits have prompted widespread criticism and a congressional investigation.

A final decision isn’t likely until next spring, said the Centers for Medicare and Medicaid Services, or CMS, although an initial ruling could come in six months. Currently Medicare is making case-by-case determinations on whether to cover the medication, which is administered intravenously in a doctor’s office.

Medicare’s announcement came on the same day that Democratic leaders of two House committees asked drugmaker Biogen to turn over reams of documents on how it developed and priced the drug, and on its dealings with government officials at the Food and Drug Administration.

Although pricey drugs are now fairly commonplace, the recent approval of Aduhelm prompted an unusually intense backlash. The FDA went against the recommendation of its outside advisers in granting the approval, and the beleaguered agency has since curtailed the recommended use of the drug and requested an investigation by an independent watchdog into its dealings with Biogen. Meanwhile, Democrats in Congress are moving legislation authorizing Medicare to negotiate drug prices.