Alzheimer’s drug slowed the progression of the disease in the phase 3 study
Japanese drugmaker Eisai said Tuesday that its experimental Alzheimer’s disease drug helped slow cognitive decline in patients in the early stages of the disease.
The company said that in a phase 3 clinical trial, the drug, called lecanemab, slowed cognitive decline by 27% after 18 months. The results were announced in a press release and have not yet been peer-reviewed.
The results may give renewed hope to Alzheimer’s patients after US drugmaker Biogen’s failed rollout of its drug, Aduhelm, last year. Biogen collaborated with Eisai in the commercialization of the new drug, although Eisai led the development and phase 3 study.
However, outside experts urged caution in interpreting the results.
The results are “a first step toward having a significant impact on the disease,” said Dr. Ronald Petersen, a neurologist at the Mayo Clinic in Rochester, Minnesota.
Dr. Alberto Espay, a neurologist at the University of Cincinnati College of Medicine, said the benefit was “small” and fell below the threshold of what would be meaningful to a patient. Still, he said, “patients can view this with cautious optimism.”
The results were based on 1,795 patients, who were randomly assigned to either the drug or placebo every two weeks over 18 months. Cognitive decline was measured using a clinical dementia rating scale that focused on six areas: memory, orientation, judgment and problem solving, community affairs, home and hobbies, and personal care.
Brain swelling was seen in 12.5% of those given the drug, compared with 1.7% in the placebo group, according to Eisai. However, many of those with brain swelling did not experience symptoms, and the incidence of that side effect was lower than that seen with other similar experimental drugs, the company said on a telephone call Tuesday.
Eisai said it will present the findings at an Alzheimer’s conference in late November and that it plans to submit the trial data to the Food and Drug Administration for approval by March.
However, the company noted that the FDA has already agreed to review the drug under the agency’s so-called accelerated approval pathway — the same process used to approve Biogen’s Aduhelm. Eisai said the agency is expected to make a decision on conditional approval by early January.
Eisai’s drug is a monoclonal antibody designed to target amyloid plaques, clumps of protein in the brain long considered a hallmark of Alzheimer’s.
Biogen’s drug Aduhelm was shown to reduce amyloid in the brain, but it did not lead to a slower progression of the disease. This leads some researchers to move away from amyloid as the cause of Alzheimer’s and look at other possibilities.
Although the results appear to be positive, the single trial is unlikely to prove that amyloid is responsible for the decline in mental function often seen in patients, Espay said.
But Petersen, of the Mayo Clinic, said the study may show that amyloid is actually one of several components that lead to the development of the disease.
“This is very positive for the field,” he said of the trial results. “I think it’s going to motivate a lot more useful research down the road.”
He also called for more research to prevent the disease, noting that the new drug “is not a cure by any means.”
Besides Biogen’s drug, all other drugs approved by the FDA for Alzheimer’s are aimed at helping symptoms, not actually slowing the progression of the disease, which is the seventh leading cause of death in the United States, according to the Centers for Disease Control and Prevention.
Two similar drugs – from Roche and Eli Lilly – are expected to release results from late-stage clinical trials in the coming months.
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