AARP Eye Center
The U.S. Food and Drug Administration (FDA) on Jan. 6 granted accelerated approval to lecanemab (brand name Leqembi), a drug that in initial clinical trials slowed the rate of cognitive decline in patients in the early stages of Alzheimer’s disease.
The medication — a monoclonal antibody that’s given by IV every two weeks — is the second of its kind to get the green light from federal regulators. Unlike most other medications approved for the disease, which affects more than 6.5 million Americans, lecanemab goes after the underlying pathology of Alzheimer’s, not just its symptoms.

A similar drug, called Aduhelm, received accelerated approval in 2021. The fast-track process used in both instances allows medications for serious conditions to come to market more quickly based on promising data, though additional studies are required to confirm the “anticipated benefit,” the FDA says.
“Alzheimer’s disease immeasurably incapacitates the lives of those who suffer from it and has devastating effects on their loved ones,” said Billy Dunn, M.D., director of the Office of Neuroscience in the FDA’s Center for Drug Evaluation and Research. “This treatment option is the latest therapy to target and affect the underlying disease process of Alzheimer’s, instead of only treating the symptoms of the disease.”

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Tackling amyloid
The specific causes of Alzheimer’s are unknown, but the disease is marked by changes in the brain, one of them being the accumulation of sticky clumps of protein, known as amyloid plaques. These plaques disrupt brain cell function and affect a person’s ability to remember and think. A leading hypothesis among researchers is that clearing them will slow the progression of the disease.
The FDA’s decision was based on phase 2 clinical trial data, which showed that participants in the early stages of Alzheimer’s disease who received lecanemab had a “statistically significant reduction in brain amyloid plaque” compared to those who received a placebo over the course of the study period.
Results from a phase 3 trial, which were published after lecanemab’s manufacturers applied for accelerated approval, support the initial findings. In a study of nearly 1,800 adults between the ages of 50 and 90 with early Alzheimer’s, participants who received lecanemab saw a reduction in amyloid levels over 18 months. What’s more, the drug was associated with “moderately less decline on measures of cognition and function” compared to the placebo, though some Alzheimer’s experts have questioned whether it’s enough to show a true benefit to patients.
The prescribing information for lecanemab includes a warning for amyloid-related imaging abnormalities, which can include swelling and bleeding in the brain. Common side effects of the drug include infusion-related reactions (this may include flu-like symptoms, nausea, vomiting and changes in blood pressure) and headache.