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FDA decision on Biogen and Eisai treatment with lecanemab

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Magnetic resonance image of the brain showing the area of ​​the patient with Alzheimer’s.

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The Food and Drug Administration on Friday granted accelerated approval for the Alzheimer’s drug lecanemab, developed by biogen and the Japanese pharmaceutical company Eisai.

The FDA approval comes after clinical trial results published in November indicated that lecanemab somewhat slows cognitive decline in people with mild impairment from Alzheimer’s disease, but the treatment also carries risks of brain swelling and bleeding.

Lecanemab will be sold under the name Leqembi.

The agency can fast track a drug’s approval to quickly bring it to market if it is expected to help patients suffering from serious illnesses more than what is currently available. Biogen and Eisai, which jointly developed the drug, applied for accelerated approval in July.

“Alzheimer’s disease immensely cripples the lives of those who suffer from it and has devastating effects 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 to target and affect the underlying process of Alzheimer’s disease rather than just treating the symptoms of the disease.”

The lecanameb decision comes after Congress issued a scathing 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 that treatment, which experts said did not show a clear clinical benefit, was “riddled with irregularities,” according to the report.

The congressional report said “the FDA must take swift action to ensure that its review processes of future treatments for Alzheimer’s disease do not lead to the same questions about the integrity of the FDA review.”

Lecanemab is a monoclonal antibody that targets a protein called amyloid, which builds up in the brains of people with Alzheimer’s. The antibody is administered intravenously every two weeks in doses determined by the patient’s body weight with 10 milligrams administered per kilogram.

Results of the clinical trial, published in the New England Journal of Medicine, found that cognitive decline was 27% slower at 18 months in people who received lecanemab compared to 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 rating, which is an 18-point scale with a higher score indicating a greater 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.

Nearly 1,800 people ages 50 to 90 with early-onset Alzheimer’s participated in the study, about half of whom received lecanemab and half did not.

Security concerns

While lecanemab may slow cognitive decline somewhat, the treatment also comes with risks.

Nearly 13% of those who received lecanemab developed brain swelling compared with about 2% in the group who did not receive the treatment. However, most of these cases were mild to moderate in severity, did not cause symptoms, and usually resolved within four months.

About 3% of patients receiving lecanemab experienced more severe cerebral edema with symptoms including headache, visual disturbances and confusion.

About 17% of those who received lecanemab had brain hemorrhage, compared with 9% in the group that did not receive the treatment. The most common symptoms associated with bleeding were dizziness.

Overall, 14% of people who received lecanemab experienced serious adverse events in the clinical trial, compared with 11% of people who did not receive the treatment.

Study authors said longer clinical trials are needed to determine the efficacy and safety of lecanemab in patients with early Alzheimer’s disease.

The death of a Chicago-area clinical trial participant may also be linked to lecanemab, according to a research letter published in the New England Journal of Medicine this week.

The 65-year-old man suffered a stroke and was hospitalized four days after the third infusion of lecanemab. A CT scan performed after the patient’s stroke found extensive bleeding in the brain. An MRI performed 81 days before the stroke found no bleeding.

The patient was also given a drug, called t-PA, used to break up blood clots that cause strokes. But extensive brain bleeding would be an uncommon complication with this drug alone, according to the doctors who wrote the research letter.

Researchers involved in the lecanemab clinical trial, in a response letter, argued that the blood clot drug appeared to be the immediate cause of the patient’s death, with the first symptoms occurring 8 minutes after receiving an infusion of the anticoagulant.

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