FAQs: What you need to know about the Alzheimer’s drug Aduhelm

The Food and Drug Administration on Monday approved Biogen’s new Alzheimer’s drug, a decision with far-reaching implications for patients, clinicians, and others. Here’s a rundown on some basic questions and answers about the drug, known as Aduhelm.

Who can get the drug?

The drug, tested in patients with mild cognitive impairment, is approved for patients with Alzheimer’s. They will need an MRI within one year of starting treatment and will also have to undergo more MRIs during treatment.

How much does it cost?

Biogen said the yearly cost for a maintenance dose of Aduhelm, based on an average patient’s weight, would be $56,000. That’s a list price, not the net price or the price paid by patients with insurance. How much patients will pay out of pocket for the drug will depend on their insurance coverage.


FDA approval means the drug will automatically be covered by Medicare, but many individual beneficiaries will have to pay 20% of the drug’s  cost.

How is it believed to work?

Aduhelm, whose scientific name is aducanumab, eliminates beta-amyloid clumps in the brain — a process that Biogen says slows their ability to destroy neurons. Not all experts are convinced that clearing the toxic proteins will slow cognitive decline. And if Biogen’s drug does work, the benefit is likely marginal. As measured by tests of cognition and function, the difference between Aduhelm and placebo was a fraction of a point on an 18-point scale.


How is the drug administered?

Aduhelm is infused intravenously over about an hour once every four weeks, potentially in a doctor’s office, infusion center, or hospital clinic. 

When will the drug be available?

Biogen expects to start shipping the drug in about two weeks to more than 900 sites across the U.S.

What kind of effect can patients expect?

The drug is not a cure and does not reverse the disease’s progression. In clinical trials, success was measured not by cognitive improvement but by slowing in the rate of cognitive and functional decline. 

Any side effects?

In two clinical trials, about 40% of clinical trial patients who got the approved dose of Aduhelm developed painful brain swelling. Symptoms included headache, dizziness, visual disturbances, nausea, and vomiting; about 17% to 18% of patients had microhemorrhages, or small bleeds in their brain. Patients will be monitored for brain swelling before their seventh and 12th infusions. If imaging shows severe swelling, treatment can continue “with caution only after a clinical evaluation and a follow-up MRI demonstrates radiographic stabilization,” the label says.

Why has this drug been so controversial?

Three reasons: First, Biogen halted two trials of aducanumab in March 2019 after independent monitors, looking at data during an interim analysis, concluded the drug was unlikely to benefit patients. A later analysis came to a different conclusion, but an FDA advisory panel convened in November 2020 found the new, positive interpretation unconvincing.  

Second, the amyloid hypothesis, which pinpoints clumps of the toxic protein as the root cause of cognitive impairment, has yet to be proven. It’s not clear if amyloid plaques, or tangles of another protein called tau, are causes or effects of Alzheimer’s. The list of amyloid-targeting drug failures is long.

Third, some experts expressed concern that the desperate need for new treatments would cause regulators to accept limited evidence of efficacy as grounds for approval. 

Are there any other drugs available now? What do they do?

Aricept, approved in 2003, and other drugs like it are designed to preserve memory by balancing certain neurotransmitters in the brain, but the effects fade over time.   

What’s in the pipeline?

Drug maker Eli Lilly presented promising results on its own Alzheimer’s drug earlier this year and has started enrolling and treating patients in a pivotal Phase 3 study.

Source: STAT