FDA approves Biogen, Eisai lecanemab treatment

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

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The Food and Drug Administration on Friday granted accelerated approval for the Alzheimer’s drug lecanemab, the second treatment for biogen and its Japanese partner Eisai to receive an early green light in less than two years.

The FDA approval comes after clinical trial results released 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 swelling cerebral and bleeding.

Eisai, which led the development of lecanemab, is pricing the treatment at $26,500 a year in the US. It will be sold under the name Leqembi.

FDA approves Biogen's Alzheimer's drug

The FDA can expedite approval of a drug to bring it to market quickly if it is expected to help patients with more serious conditions than is currently available. Biogen and Eisai applied for accelerated approval in July.

“Alzheimer’s disease immeasurably disables 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 neuroscience division, said in a statement. “This treatment option is the latest therapy to target and affect the underlying Alzheimer’s disease process, rather than just treating the symptoms of the disease.”

More than 6.5 million people in the United States have Alzheimer’s. The irreversible disease destroys memory, thinking skills and eventually the ability to perform simple tasks.

The decision on lecanameb 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. According to the report, the approval of this treatment in 2021, which experts say did not show a clear clinical benefit, was “fraught with irregularities”.

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

Modestly delays the disease

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

The FDA approved lecanemab based on reductions in amyloid plaque seen in clinical trial participants who received the treatment, according to a news release from the agency. Participants who did not receive the treatment, the placebo arm, had no reduction in amyloid plaque.

The results of the clinical trial, published in the New England Journal of Medicine, found that cognitive decline was 27% slower over 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 Score, 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 lecanemab group versus 1.66 points in the untreated group, a modest difference of 0.45 points.

Nearly 1,800 people aged 50 to 90 with early Alzheimer’s took part in the trial, about half of whom received lecanemab and half of whom did not.

Security concerns

Although lecanemab may slow cognitive decline somewhat, the treatment also carries risks.

Almost 13% of those who received lecanemab developed brain swelling compared with about 2% of the untreated group. However, most of these cases were mild to moderate in severity, caused no symptoms, and usually resolved within four months.

About 3% of patients who received lecanemab had more severe brain swelling with symptoms that included headache, visual disturbances and confusion.

About 17 percent of those who received lecanemab had brain bleeding, compared with 9 percent of the group that did not take 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 those who did not receive treatment.

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

The FDA said the prescribing information for lecanemab will include a warning about the risk of swelling and bleeding, commonly known as amyloid-related imaging abnormalities.

The death of a clinical trial participant in the Chicago area 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 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 done 81 days before the stroke had found no bleeding.

The patient had also received a drug, called t-PA, used to break up blood clots that cause strokes. But extensive brain bleeding would be an unusual complication of 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-clotting medication appeared to be the immediate cause of the patient’s death, with the first symptoms occurring 8 minutes after receiving an infusion of the blood clot destroyer.

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