The $56,000 yearly price tag for Biogen Inc.'s freshly authorized Alzheimer's medicine is gaining traction ahead of a decision by the US government on reimbursement procedures.

In a letter to congressional leaders on Monday, the Businesses' Prescription for Affordable Drugs, a coalition of health-care purchasers, claimed that taxpayers and employers will be forced to spend billions of dollars for the drug, named Aduhelm, without knowing whether it works.

The group argued that Aduhelm's approval and pricing are a "cautionary story of a flawed system in desperate need of reform."

Despite an advisory committee's misgivings, the Food and Treatment Administration awarded Aduhelm speedy approval last month, despite a lack of strong evidence that the drug could prevent patients' cognitive impairment. Biogen must continue to research the medicine, according to regulators.

Regardless of the debate about its merits, Aduhelm could be adopted by millions of Americans, imposing a significant additional expense on taxpayers, businesses, and households. Patients who take the medicine are expected to need monthly scans to assess treatment success and adverse effects, in addition to the hefty list price.