A study published in the New England Journal of Medicine in late November shows promising signs for Alzheimer’s treatment. The findings revealed that the drug lecanemab, developed jointly by Biogen and Eisai, suppressed cognitive decline in individuals with early signs of the degenerative disease. Still, it came with health risks for some patients.
According to the researchers, while the lecanemab slowed cognitive decline, it was also “associated with adverse events,” like bleeding and swelling of the brain.
The drug helps protect memory and thinking by targeting amyloid beta. The authors sought to test a decades-old theory that posited Alzheimer’s is driven by these amyloid beta plaques found in the brain, and by reducing their buildup, cognitive deterioration would slow.
Pharmaceutical companies have tried and failed to target the plaques in previous tests. In October, Roche revealed disappointing results of a late-stage study to treat Alzheimer’s using a drug called gantenerumab. Unfortunately, its effectiveness at reducing amyloid was found to be statistically insignificant.
Biogen successfully obtained FDA approval for a drug targeting amyloid beta plaques in 2021. Unfortunately, the approval was shrouded in controversy because it was based on two studies that closed early and netted different conclusions.
Maria Carrillo, chief science officer of the Alzheimer’s Association, is encouraged by the latest news around lecanemab’s effectiveness. The findings confirm the “treatment can provide a meaningful change in the course of a disease for people at the earliest stages of Alzheimer’s,” said Carrillo.
The study’s authors presented their data on November 30 at the Clinical Trials on Alzheimer’s Disease conference in San Francisco. The data revealed that lecanemab nets moderate benefits, but it also carries potential side effects for some patients.
For the study, Eisai and Biogen analyzed nearly 1,800 patients with early-onset Alzheimer’s disease and discernable amyloid beta deposits in the brain. The patients were administered either a placebo or a 10 mg per kilogram dose of lecanemab every two weeks over 18 months.
In September, the companies jointly announced cognitive decline had fallen 27% for the patients taking the drug versus the placebo.
Individuals with early stages of Alzheimer’s who took lecanemab witnessed “moderately less decline on measures of cognition and function” compared to their peers taking a placebo, said the study. However, side effects, like brain swelling, were also discovered in the group taking the drug.
Roughly 25% of the patients taking lecanemab experienced “infusion-related” reactions, a hypersensitive response to a pharmacological or biological substance. Over 10% also experienced cerebral edema, or brain swelling, according to scans taken during the study. A smaller number, less than 1%, reported chest pain, fainting, or irregular or rapid heartbeats.
Nearly 7% of the participants dropped out due to the side effects, over double the control group.
Previous reports had linked lecanemab to two deaths, the most recent being a patient who suffered a stroke and was administered medication to help break up blood clots. However, the study found fewer than 1% of patients died while on the drug or placebo, and researchers concluded that “no deaths were considered … to be related to lecanemab.”
Eisai’s CEO of their Americas region, Ivan Cheung, says independent experts have verified the efficacy and safety of the drug.
“These clinical efficacy results and biomarker results really translate into delaying disease progression as well as improved health-related quality of life,” says Cheung.
Eisai and Biogen expect the Food and Drug Administration to decide on the drug’s accelerated approval by early January 2023.