Biogen Inc. expects gradual uptake of its new Alzheimer’s disease drug in the U.S. and said it would consider adjusting its US$56,000-a-year price if the medication is taken by more patients than anticipated.

The disclosure in a company statement Wednesday is a signal the drugmaker wants to tamp down the outcry over the treatment’s potential costs to the U.S. health-care system. The company said it set the price based on the impact of the treatment and assumptions about how many people would take it.

If those turn out to be wrong, “we stand ready to work with public and private payers to address pricing in order to achieve both patient access and support budget sustainability,” the company said in the statement issued with its partner Eisai Inc.

A company spokesperson didn’t immediately respond to emailed questions. Biogen shares fell as much as 2.6 per cent as of 11:53 a.m. in New York.

The biotech has faced criticism over the price of the monthly infusion, called Aduhelm, and skepticism about its benefits. The Food and Drug Administration granted the drug accelerated approval this month over the objection of the agency’s scientific advisers and despite conflicting evidence from clinical trials about whether the drug slows progression of the debilitating brain illness.

Under fire

Biogen said it’s working “with urgency” to conduct a trial required by U.S. regulators to confirm the effect of Aduhelm in less time than the nine years it agreed to with the FDA.

The company is under fire from advocates and lawmakers who say costs of drug threaten to overwhelm Medicare. Biogen has said it’s appropriate for between 1-2 million people in the U.S. who resemble the patients in the trials, who had mild cognitive impairment due to Alzheimer’s.

The annual cost for a million patients would top US$57 billion, according to estimates from the Kaiser Family Foundation. That would exceed the current spending on all drugs by Medicare’s Part B program, which covers therapies administered by physicians.

Biogen hasn’t said how many patients it expects to take the drug initially, but not all of them will get it at once. Testing needed to identify appropriate patients and a limited number of specialists will slow down adoption, the company said.

Gradual uptake

“We anticipate that patient uptake will be gradual over a number of years,” the company said.

Biogen has already pledged not to increase the price of Aduhelm for four years. Wednesday’s statement emphasized that it was interested in working with health-care payers, including Medicare, on pricing agreements. The company expects 80 per cent of Aduhelm patients to be covered by Medicare.

The company said it would work with the government health program on “innovative price and access agreements,” such as volume-based arrangements “that would help support continued sustainability of Medicare budgets.”

Most patients would have either low out-of-pocket expenses or a cap on total costs through private insurance that replaces or supplements traditional Medicare. But about 1 in 10 patients might have to pay 20 per cent of their total costs out-of-pocket, with no limit, and Biogen said it would work to connect them with financial assistance programs.