US health officials on Friday approved a closely watched Alzheimer’s drug that modestly slows the brain-robbing disease, albeit with potential safety risks that patients and their doctors will have to carefully weigh.
The drug, Leqembi, is the first to be conclusively shown to slow the decline in memory and thinking that define Alzheimer’s disease by targeting the underlying biology of the disease. The US Food and Drug Administration (FDA) has approved it for Alzheimer’s patients, particularly those with mild disease or in the early stages of the disease.
Leqembi, from Japan’s Eisai and its US partner Biogen, is a rare success in a field accustomed to failed experimental treatments for the incurable condition. The delay in cognitive decline caused by the drug probably amounts to only a few months, but some experts say it can still significantly improve people’s lives.
“This medicine is not a cure. It doesn’t stop people from getting worse, but it significantly slows the progression of the disease,” said Dr. Joy Snyder, a neuroscientist at Washington University in St. Louis. “That could mean someone could have an extra six months to a year before they can drive.”
Snyder emphasized that the drug has drawbacks, including the need for twice-monthly infusions and possible side effects such as brain swelling.
A picture of a human brain taken using a PET scan at a hospital in France in January 2019 (Fred Tanneau/AFP/Getty Images)
The FDA’s approval came through its fast track, which allows drugs to be brought to market based on early results before they are confirmed to benefit patients. The agency’s use of this shorthand approach has come under increasing scrutiny from government watchdogs and congressional investigators.
Last week, a congressional report found that the FDA’s approval of a similar Alzheimer’s drug called Aduhelm — also from Biogen and Eisai — was “riddled with irregularities,” including a series of meetings with drug company officials that went undocumented.
The trial of the new drug, known chemically as lecanemab, likely means most patients won’t start receiving it for months while insurers decide whether and how to cover it.
The drug will cost about US$26,500 (C$35,613) for a typical one-year treatment. Eisai said the price reflects the drug’s benefit in terms of improved quality of life, reduced burden on caregivers and other factors. The company put its value at more than US$37,000 (C$49,725) a year, but said it set the price lower to reduce costs for patients and insurers. An independent group that evaluates the drug’s value recently said the drug would need to cost less than $20,600 US ($27,684 Cdn) a year to be cost-effective.
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About six million people in the U.S. and many more worldwide have Alzheimer’s, which gradually attacks areas of the brain needed for memory, reasoning, communication and everyday tasks.
The FDA approval was based on a mid-stage study of 800 people with early signs of Alzheimer’s who could still live independently or with minimal assistance.
Eisai has since published the results of a larger study with 1,800 patients, which the FDA will review to confirm the drug’s benefit, paving the way for full approval later this year.
Today, we approved a new drug for the treatment of Alzheimer’s disease, the second in a new class of drugs approved for Alzheimer’s disease that target the underlying pathophysiology of the disease. pic.twitter.com/TV36k6CO6K
—@US_FDA
The larger study tracked patients’ scores on an 18-point scale that measures memory, judgment and other cognitive abilities. Doctors compile the rating from interviews with the patient and close contact. After 18 months, patients receiving Leqembi declined more slowly — a difference of less than half a scale point — than patients receiving a sham infusion. The delay amounts to just over five months.
There is little consensus as to whether this difference translates into real benefits for patients, such as greater independence.
“Most patients won’t notice the difference,” said Dr. Matthew Schrag, a neuroscience researcher at Vanderbilt University. “It’s really quite a small effect and probably below the threshold of what we would call clinically significant.”
Schrag and some other researchers believe that a meaningful improvement would require a difference of at least one full point on the 18-point scale.
“I have pretty serious doubts”
Leqembi works by clearing a sticky brain protein called amyloid, which is one of the hallmarks of Alzheimer’s. But it’s not clear what exactly causes the disease. A number of other drugs targeting amyloid have failed, and many researchers believe that combination treatments will be needed.
Aduhelm, a similar drug, has been marred by controversy over its effectiveness.
The FDA approved this drug in 2021 against the advice of the agency’s outside experts. Doctors hesitated to prescribe the drug and insurers limited coverage.
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There is debate over whether Canada should follow the US lead and approve a controversial Alzheimer’s drug despite concerns that Aducanumab is ineffective and could be harmful. But the uncertainty doesn’t stop some patients from wanting to try the drug.
The FDA did not consult the same expert panel before approving Leqembi.
While there is “less drama” surrounding the new drug, Schrag said many of the same concerns apply.
“Is this mild, measurable benefit worth the high cost and side effects patients may experience?” he asked. “I have serious doubts.”
About 13 percent of patients in Eisai’s study had brain swelling and 17 percent had small brain hemorrhages, side effects seen with earlier amyloid-targeting drugs. In most cases, these problems do not cause symptoms, which can include dizziness and vision problems.
Additionally, several Leqembi users died while taking the drug, including two who were on blood thinners. Eisai said the deaths could not be attributed to the drug. The FDA label warns doctors to use caution if they prescribe Leqembi to patients on blood thinners.
Insurers are likely to cover the drug only for people like those in the company’s study — patients with mild symptoms and confirmation of amyloid buildup. This usually requires expensive brain scans. A separate type of scan will be needed to periodically monitor for brain swelling and bleeding.
A question about Medicare
A key issue in the drug’s release will be the decision about coverage by Medicare, the federal health plan that covers 60 million seniors and other Americans. The agency severely limited coverage of Aduhelm, essentially killing the U.S. market and forcing Biogen to abandon marketing plans for the drug.
Eisai executives said they have already spent months discussing their drug’s data with Medicare officials. Coverage is not expected until the FDA confirms the drug’s benefit, likely later this year.
“Once we have a solution for Medicare, then we can really roll out the drug nationwide,” said Eisai’s U.S. CEO, Ivan Cheung.
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Betsy Groves, 73, of Cambridge, Massachusetts, was diagnosed with Alzheimer’s in 2021. A former faculty member at Harvard’s School of Education, she noticed she was having trouble remembering some students’ names and answering questions.
Her initial diagnosis, based on a cognitive examination, was later confirmed by a positive test for amyloid.
Groves says he is “more than willing” to try Leqembi, despite the potential side effects and the need for infusions.
“For me, the moment this drug comes out — and I get my doctor’s approval — I’m going to take it,” Groves said.
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