US regulators on Thursday gave full approval, for the first time, to a drug shown to modestly slow cognitive decline in people with early Alzheimer’s. The medicine, called Leqembi, carries risks of serious side effects, but has also given hope to millions affected by the memory-ravaging disease.
The treatment will cost $26,500 a year per patient, according to Biogen, the Cambridge drug maker, and its Japanese business partner Eisai, which co-developed the medicine.
After the closely watched decision by the Food and Drug Administration, Medicare administrators swiftly indicated the federal government will cover the costs of the medicine for enrollees who meet the insurer’s criteria: They must be diagnosed with mild Alzheimer’s disease and have documented evidence of beta amyloid, a sticky protein that forms plaques in the brains of some patients.
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Administered through an intravenous infusion every two weeks, Leqembi reduced cognitive decline by 27 percent compared to a placebo over an 18-month trial involving nearly 1,800 people who were in the early stages of the disease, a clinical study found.
It remains to be seen how much the clinical results will translate into the quality-of-life improvements most meaningful to patients and their families, such as lengthening the time people with early Alzheimer’s can continue to drive or live independently.
“Today’s action is the first verification that a drug targeting the underlying disease process of Alzheimer’s disease has shown clinical benefit in this devastating disease,” Teresa Buracchio, acting director of the office of neuroscience in the FDA’s Center for Drug Evaluation and Research, said in a statement.
Alzheimer’s patients, experts, and advocates hailed the approval and predicted it will spur the discovery of even better drugs.
“This is truly a momentous occasion,” said Joe Montminy, 59, a Plymouth resident diagnosed with Alzheimer’s who said he will seek a Leqembi prescription. “It’s a time when there’s more hope than ever before in treating Alzheimer’s disease.”
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The FDA gave conditional approval to Leqembi in January, concluding that it significantly reduced levels of amyloid. That reduction, regulators said, indicated Leqembi would likely provide benefit to patients.
But the Centers for Medicare and Medicaid Services, which administers federal health insurance for Americans over 65, declined to reimburse patients receiving the drug outside clinical trials until the FDA had conducted a more thorough review and granted full approval.
CMS said it would pay for Leqembi and similar Alzheimer’s drugs on the horizon under certain conditions, including that patients enroll in an online registry and their doctors collect data on how well the medicines work.
“CMS today affirms our commitment to help people with Alzheimer’s disease have timely access to innovative treatments that may lead to improved care and better outcomes,” CMS administrator Chiquita Brooks-LaSure said in a statement.
Medicare coverage is important not only for seniors who make up the bulk of Alzheimer’s patients, but to others with private insurance. Those insurers often follow Medicare’s lead. Medicare enrollees typically need to have supplemental insurance to cover part of a medicine’s costs or they will have to pay the balance out of pocket.
The approval represents a comeback for Biogen, which won conditional approval of another Alzheimer’s drug in 2021 that it also developed with Eisai. That medicine, Aduhelm, was cleared over the objections of independent scientific advisers to the FDA who said its risks exceeded its benefits to patients. After Medicare refused to cover the drug for most patients, Aduhelm flopped.
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Leqembi is among a new class of amyloid-clearing medicines for Alzheimer’s, which afflicts more than 6.7 million Americans. In clinical studies, the treatments have shown modest but measurable evidence of slowing decline in patients with mild cognitive impairment. But the new class of drugs comes with risks, including the possibility of bleeding and swelling in the brain.
Indeed, regulators added a “black-box warning” — the most urgent kind — to Leqembi’s drug label on Thursday, saying that in rare cases the medication can cause “serious and life-threatening events.”
An advisory committee, made up of independent scientific experts, unanimously recommended on June 9 that the FDA approve Leqembi, determining the potential benefits outweighed the risks.
Hugh Courtney, a former Northeastern University economics professor who was diagnosed with Alzheimer’s 2½ years ago and has participated in the trial of Leqembi for 18 months, said he was “thrilled” with the FDA’s decision.
”This will give more people a chance,” said Courtney, 60, of Concord, who stepped down from his academic job after his diagnosis.
FDA approval and Medicare coverage of Leqembi will also accelerate investment in Alzheimer’s research and “set a pathway” for other experimental drugs already in late-stage clinical trials, said Dr. Howard Fillit, executive director of the Alzheimer’s Drug Discovery Foundation in New York, which funds dozens of research programs.
Fillit said many of these drugs could be in commercial use within the next five years, including some aimed at non-amyloid targets such as inflammation.
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Dr. Alvaro Pascual-Leone, a neurology professor at Harvard Medical School who treats Alzheimer’s patients at the Deanna and Sidney Wolk Center for Memory Health at Hebrew SeniorLife, said he expects a surge in requests for Leqembi.
However, he said he’s concerned families may overestimate the likely benefits of the drug and underestimate its risks. At best, he said, the medicine slowed the progression of Alzheimer’s by almost 30 percent in the trial; it did not reverse cognitive impairment at all.
Still, he said, “being able to make it six months longer and attend your granddaughter’s graduation may be priceless.”
Besides brain swelling, Leqembi also poses risks of microhemorrhages. Although those side effects are generally mild and without obvious symptoms, they can be life-threatening, according to the FDA. Three patients died during the clinical trial.
The risks appear to be greater in patients who carry a gene known to dramatically heighten the chances of developing Alzheimer’s — apparently because the drug binds to and breaks up more amyloid, which could lead to bleeding and swelling.
About 25 percent of the US population has one copy of that gene, known as APOE4, which doubles or triples the risk of developing Alzheimer’s, according to the National Institute on Aging. About 2 or 3 percent of people have two copies, which increases the risk of developing the disease twelvefold.
The FDA said Thursday that Alzheimer’s patients should be tested for the gene before taking Leqembi and that those on blood thinners should be informed they are at higher risk for bleeding in the brain.
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Alzheimer’s takes an enormous toll on society, and it’s only expected to grow. By 2050, as the US population ages, the number of patients is projected to more than double to 13 million. Worldwide, more than 55 million people are estimated to have Alzheimer’s.
Biogen and Eisai won’t have the market to themselves for long. Encouraging clinical findings in May from a competing Eli Lilly medicine, called donanemab, could lead to FDA approval by year-end and set up a competition for tens of billions of dollars in projected sales.
Biogen executives have cautioned it will take time for the Alzheimer’s drug market to develop. Chief executive Chris Viehbacher estimated in a May interview that 100,000 patients will receive Leqembi over the next three years, with the patient population growing from there.
In the short term, neurologists will need to be educated on who can benefit and how to administer treatments. That will require an infrastructure of diagnosis and infusion centers across the nation, which doesn’t now exist, Viehbacher said. Getting Alzheimer’s drugs to patients in rural settings, and to those who lack access to health resources in cities, will be another hurdle.
In May, researchers from the University of California Los Angeles concluded that Leqembi could boost Medicare’s annual spending by $2 billion to $5 billion.
Dr. Sam Gandy, who runs a center for cognitive health at New York’s Mount Sinai Health System, which opted not to offer Aduhelm to patients over concerns about its safety and effectiveness, said he expects to begin prescribing Leqembi in August or September.
“I think it’s an important advance in the field,” he said. “The data are all very clear and make sense.”
Although the benefits of the drug are relatively modest, Gandy said, the clinical trials suggested the slowing progression of the disease may become more obvious the longer patients remain on Leqembi.
“It certainly doesn’t reverse the disease,” he said. “But it’s a clear step in the right direction.”
Robert Weisman can be reached at robert.weisman@globe.com. Jonathan Saltzman can be reached at jonathan.saltzman@globe.com.