MRI image of brain showing area of Alzheimer’s patient.
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The Food and Drug Administration on Friday granted accelerated approval for Alzheimer’s drug lecanemab, the second treatment out biogenic and its Japanese partner Eisai received the early green light in less than two years.
The FDA’s approval comes after clinical trial results released in November indicated that lecanemab may slow cognitive decline somewhat in people with mild impairment from Alzheimer’s disease, but the treatment also carries the risk of brain swelling and bleeding.
Eisai, who led the development of lecanemab, is pricing the treatment at $26,500 a year in the US. It is sold under the Leqembi name.
The FDA may expedite approval of a drug to get it to market quickly if it is expected to help patients with serious illnesses more than is currently available. Biogen and Eisai filed for accelerated approval in July.
“Alzheimer’s disease immeasurably impacts the lives of those who suffer from it and has a devastating impact on their loved ones,” said Dr. Billy Dunn, director of the FDA’s Division of Neuroscience, in a statement. “This treatment option is the latest therapy that targets and affects the underlying disease process of Alzheimer’s rather than just treating the symptoms of the disease.”
More than 6.5 million people in the US suffer from Alzheimer’s. The irreversible disease destroys memory, the ability to think, and eventually the ability to perform simple tasks.
The decision on lecanameb came after Congress released a damning report last week on how the FDA handled the controversial approval of another Alzheimer’s drug developed by Biogen and Eisai called Aduhelm. The 2021 approval of this treatment, which experts said showed no clear clinical benefit, was “riddled with irregularities,” according to the report.
The congressional report said the “FDA must act quickly to ensure that its processes for reviewing future treatments for Alzheimer’s disease do not raise the same doubts about the integrity of the FDA’s review.”
Slightly slows down the disease
Lecanemab is a monoclonal antibody that targets a protein called amyloid, which builds up in the brain of people with Alzheimer’s. The antibody is given intravenously every two weeks in doses based on a patient’s body weight, given 10 milligrams per kilogram.
The FDA approved lecanemab based on the reduction in amyloid plaque observed in clinical trial participants who received the treatment, the agency said in a statement. Participants who did not receive the treatment, the placebo arm, had no reduction in amyloid plaques.
The results of the clinical study, published in the New England Journal of Medicine, found that people who received lecanemab had a 27% slower rate of cognitive decline over 18 months than those who did not receive the treatment. The study was funded by Biogen and Eisai.
Cognitive decline was measured using a system called the Clinical Dementia Score, an 18-point scale, with a higher score indicating a higher level of impairment. It measures cognitive functions such as memory, judgment and problem solving.
Alzheimer’s disease progressed by an average of 1.21 points in the group that received lecanemab, compared with 1.66 points in the group that did not receive the treatment, a modest difference of 0.45 points.
Almost 1,800 people aged 50 to 90 with early-stage Alzheimer’s took part in the study, about half of whom received lecanemab and half did not.
security concerns
Although lecanemab may slow cognitive decline somewhat, the treatment also comes with risks.
Almost 13% of the patients who received lecanemab developed brain swelling, compared with around 2% in the group that did not receive the treatment. However, most of these cases were mild to moderate, did not cause symptoms, and usually resolved within four months.
About 3% of patients receiving lecanemab had more severe brain swelling, with symptoms such as headache, blurred vision and confusion.
Around 17% of the patients who received lecanemab had bleeding in the brain, compared with 9% in the group not taking the treatment. The most common symptom associated with the bleeding was dizziness.
Overall, 14% of people who received lecanemab experienced serious adverse events in the clinical study, compared with 11% of people who did not receive treatment.
The study authors said longer clinical trials are needed to determine the efficacy and safety of lecanemab in patients with early Alzheimer’s disease.
The FDA said the prescribing information for lecanemab will include a warning about a risk of swelling and bleeding, commonly referred to as amyloid-related imaging abnormalities.
The death of a participant in a clinical trial in the Chicago area could also potentially be linked to lecanemab, according to a research letter published this week in the New England Journal of Medicine.
The 65-year-old suffered a stroke and was hospitalized four days after the third lecanemab infusion. A CT scan performed after the patient’s stroke revealed severe bleeding in the brain. An MRI done 81 days before the stroke had found no bleeding.
The patient had also been given a drug called t-PA, which is used to break up blood clots that cause strokes. However, according to the physicians who wrote the research letter, extensive cerebral hemorrhage would be an unusual complication of this drug alone.
Researchers involved in the lecanemab clinical trial argued in a reply letter that the blood clot drug appeared to be the immediate cause of the patient’s death, with the first symptoms appearing 8 minutes after receiving an infusion of the blood clot breaker.
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