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In preliminary decision, Medicare offers only limited coverage of Aduhelm

Biogen has gained and shed billions of dollars in market value as a result of Aduhelm’s fluctuating prospects.Steven Senne/Associated Press

Medicare said Tuesday that it will cover Biogen’s controversial $28,000-a-year Alzheimer’s drug Aduhelm only for patients who participate in clinical trials, an extraordinary move that will significantly restrict the number of people who can get a costly medicine whose benefits and risks have been fiercely debated.

The preliminary decision by the Centers for Medicare and Medicaid Services represents a highly unusual case of the agency balking at fully covering a drug that had been approved by another government agency, the Food and Drug Administration. It is also another stinging setback for the Cambridge-based biotech.

Medicare has occasionally declined to cover an FDA-approved medical device or technology, but experts couldn’t cite a precedent for doing that with an approved drug.


Dr. Lee A. Fleisher, CMS’s chief medical officer, said in a news conference that the “national coverage determination” followed a rigorous six-month analysis by experts. It determined that “while there may be the potential for promise with this treatment, there is also the potential for harm to patients,” he said.

“We believe that any appropriate assessment of patient health outcomes must weigh both harm and benefit before arriving at a final decision,” Fleisher added.

Biogen had envisioned Aduhelm as a potential blockbuster drug that could be marketed to people with mild Alzheimer’s-related dementia, a population estimated to be 1.5 million Americans. If the decision stands, only a tiny fraction of them would likely get access to it.

Even before Aduhelm was approved last June, medical experts repeatedly raised concerns about potentially serious side effects experienced by patients who received it in clinical trials. About 40 percent of patients who got the highest dose showed abnormalities on MRI scans, indicating brain swelling or tiny hemorrhages. More than three-quarters of those imaging abnormalities caused no symptoms, but about 6 percent of patients on the highest dose had to stop taking the drug.


The draft decision, if finalized, doesn’t apply just to Aduhelm, but to several other similar experimental Alzheimer’s medicines from multiple companies that are in clinical trials and could come before the FDA soon. Like Aduhelm, the drugs are monoclonal antibodies that target a sticky protein called amyloid that clumps into plaques in the brains of people with Alzheimer’s. Some doctors believe amyloid buildup causes cognitive impairment, although that’s unproven and strongly contested by some experts.

CMS plans to make a final decision by April 11. The agency invited public comments over the next 30 days.

People and organizations on both sides of the controversy were quick to weigh in on the CMS recommendation.

Biogen, which has gained and shed billions of dollars in market value as a result of Aduhelm’s fluctuating prospects, said the announcement “denies the daily burden of people living with Alzheimer’s disease.” Limiting the coverage to people in clinical trials “will exclude almost all patients who may benefit,” it said.

Biogen said that trials to gather the evidence sought by CMS “can take months to years to initiate, and hundreds of Alzheimer’s patients ― the majority of whom are Medicare beneficiaries ― are progressing each day from mild to moderate disease stages, where treatment may no longer be an option.”

John Dwyer, president of the Global Alzheimer’s Platform Foundation, a Washington, D.C.-based nonprofit that seeks to speed the development of treatments for the disease, called CMS’s decision “unprecedented, reckless and stands in direct opposition to the president’s personal commitment to better address the Alzheimer’s public health crisis in the US.”


But several physicians who had raised doubts about the safety and effectiveness of Aduhelm expressed relief.

Dr. Aaron Kesselheim, a Harvard Medical School professor who resigned from an independent panel of scientific advisers to the FDA along with two other members after the agency approved Aduhelm over the committee’s objections, said he would have preferred that regulators never cleared the drug.

“Since that didn’t happen, it is welcome to see CMS decide not to cover the drug in wide clinical use but to instead require it be administered in the context of a clinical trial, acknowledging that the effectiveness of this drug has not been demonstrated sufficiently,” he said in an e-mail.

Dr. Peter Bach, who chairs a committee that advises Medicare on which treatments to cover ― but which was not asked to weigh in on Aduhelm ― tweeted that it was “nice to see the draft [decision] today.” He recently told the Globe that Medicare should cover the drug only for patients who agree to be in a rigorously run trial where Aduhelm would be compared with a placebo.

CMS officials said the agency would also have to approve the clinical trials, which would take place in hospital-based settings and could be managed with help from the National Institutes of Health. But many questions remained unanswered, including how many patients might be allowed to participate and precisely when they would start.


About 80 percent of potential Aduhelm patients are old enough to receive Medicare, making coverage crucial. Aduhelm is the first new treatment since 2003 for Alzheimer’s, a progressive and fatal memory-robbing disease that afflicts about 5.8 million Americans.

Biogen initially priced the medicine at $56,000 a year, which drew denunciations even from some groups that lobbied for its approval, including the Alzheimer’s Association. Some private insurers said they would not cover the drug, including Massachusetts’ two biggest insurers, Blue Cross Blue Shield of Massachusetts and Point32Health.

At least 16 university-affiliated hospital systems across the United States, including Mass General Brigham, said they have weighed the benefits and risks of the drug and won’t offer it to patients, according to a recent story published by STAT.

One of the most closely watched experimental drugs in recent history, Aduhelm, which is given intravenously monthly, generated contradictory results in two late-stage clinical trials. In one study, people with Alzheimer’s who received the drug declined 22 percent more slowly on average than those who got a placebo. The other trial failed to reach its goal.

As a result, many analysts and scientific experts were shocked by Aduhelm’s approval, which came amid pressure from families of people with Alzheimer’s and their advocates. The FDA cleared the drug under a less common “accelerated approval pathway” reserved for medicines that fill a serious unmet need.

The FDA typically uses this tack when regulators are uncertain about the clinical benefits of a drug and rely on another measure that suggests it would help patients. In this case, that was Aduhelm’s reduction of amyloid plaques. That reduction, Biogen said, was “reasonably likely to predict” that the drug will benefit such patients.


Given the demand for an effective Alzheimer’s treatment, Biogen and its Japanese business partner, Eisai, had hoped the drug would be a blockbuster, but sales have been anemic. Last month, Biogen cut the wholesale price of the drug in half, to $28,200 a year, after its high cost spurred concerns that it could strain Medicare and insurers. Nonetheless, even some advocates of the drug say that’s still too high.

Before Biogen slashed the price, Medicare’s actuarial division imposed one of the biggest-ever increases in Medicare Part B monthly premiums for 2022, and about half of it was as a result of a possible decision to cover the drug. The new premium is $170.10, up from $148.50 in 2021. Xavier Becerra, Health and Human Services secretary, on Monday ordered Medicare to reconsider the historic increase, given the price cut.

Jonathan Saltzman can be reached at jonathan.saltzman@globe.com.