In a Reversal, F.D.A. Calls for Limits on Who Gets Alzheimer’s Drug

Facing sharp criticism for approving a controversial drug for all Alzheimer’s patients, the Food and Drug Administration has greatly narrowed its recommendation, suggesting that only those with mild memory or thinking problems should receive it.

The F.D.A.’s turnabout, highly unusual for a drug that has only been available for a few weeks, could considerably reduce the number of eligible patients. The initial label, saying the drug could be appropriate for anyone with Alzheimer’s, encompassed about six million Americans. Under the revised label, as many as two million Americans would still likely be eligible.

Medicare and private insurers may use the new label to restrict coverage of the drug, called Aduhelm. That could alleviate the drug’s financial burden, particularly on Medicare, which is expected to shoulder the bulk of costs of the treatment, a monthly intravenous infusion. The drug’s maker, Biogen, is charging $56,000 annually for the drug, and costs for diagnostics and safety monitoring could add tens of thousands of dollars to the bill.

“Since the agency approved Aduhelm, prescribers and other stakeholders have expressed confusion regarding the intended population for treatment,” said Michael Felberbaum, a spokesman for the F.D.A. The agency’s new position is that “it is appropriate to initiate treatment in patients with the mild cognitive impairment or mild dementia stages of Alzheimer’s disease,” he said.

The approval of Aduhelm has been one of the most contentious F.D.A. decisions in recent years, largely because many scientists, and the F.D.A.’s own independent advisory committee, say the evidence does not convincingly show that the drug works. And in addition to the approval itself, the agency’s surprisingly broad label caused a storm of concern among many Alzheimer’s experts, even those who had supported the drug’s approval.

The F.D.A. initiated the labeling change, and Biogen agreed to submit revised language. Biogen had said in recent weeks that it intended to market the use of the drug to patients who resembled those in the clinical trial.

In one late-stage clinical trial, the highest dose of the drug appeared to slow patients’ cognitive decline by a fraction of a point on an 18-point scale rating memory, problem-solving skills and function. But in a second identically designed clinical trial, the drug showed no benefit at all.

The agency approved the drug under a pathway known as accelerated approval, more commonly used for cancer drugs, based on the drug’s ability to reduce levels of a protein, amyloid, that clumps into plaques in the brains of Alzheimer’s patients and is considered a biomarker of the disease. But many Alzheimer’s experts say there is not yet convincing evidence that reducing levels of amyloid can produce any effect on people’s memory and thinking problems.