Lecanemab (Leqembi) was approved under the accelerated approval pathway to treat Alzheimer's disease, the on Friday.
The anti-amyloid should be started only in patients with mild cognitive impairment or who are at the mild dementia stage of Alzheimer's disease, the population studied in clinical trials, the agency noted, and the indicates there are no safety or effectiveness data on initiating treatment at earlier or later stages of the disease.
Lecanemab becomes the second anti-amyloid agent approved for Alzheimer's under this , the first being aducanumab (Aduhelm) in 2021.
"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," Billy Dunn, MD, director of the Office of Neuroscience at FDA's Center for Drug Evaluation and Research, said in a statement.
The agency's accelerated approval decision was based on the a that showed patients receiving lecanemab had a significant reduction in amyloid beta plaques. "The results of a phase III randomized, controlled clinical trial to confirm the drug's clinical benefit have recently been reported and the agency anticipates receiving the data soon," the FDA noted.
In the phase III study, lecanemab led to modestly less decline on cognitive and functional measures in early Alzheimer's disease but was associated with adverse events, Christopher van Dyck, MD, of Yale School of Medicine in New Haven, Connecticut, and co-authors reported in the New England Journal of Medicine.
"Longer trials are warranted to determine the efficacy and safety of lecanemab in early Alzheimer's disease," the researchers wrote.
From a baseline score of about 3.2 on the Clinical Dementia Rating-Sum of Boxes (CDR-SB), mean worsening at 18 months was 1.21 with lecanemab and 1.66 with placebo, a difference of -0.45 (95% CI -0.67 to -0.23, P<0.001). The CDR-SB scale ranges from 0-18, with higher scores indicating worse impairment.
All key secondary endpoints were met in the trial. A total of 26.4% of lecanemab-treated participants had infusion-related reactions. Amyloid-related imaging abnormalities (ARIA) with edema or effusions (ARIA-E) occurred in 12.6% of people who received lecanemab. ARIA-H -- combined cerebral microhemorrhages, cerebral macrohemorrhages, and superficial siderosis -- occurred in 17.3%.
At least two deaths were reported in the news media involving participants who developed ARIA in the drug's open-label extension study. One death involved a participant with atrial fibrillation who was taking the blood thinner apixaban (Eliquis), the other was a 65-year-old participant who received tissue plasminogen activator (tPA) for acute stroke. recently reported in the media involved a 79-year-old participant who appeared to have died after experiencing brain swelling and bleeding, in addition to seizures.
The death of the participant who received tPA was described in a case report published in the New England Journal of Medicine this week; the patient showed scattered brain bleeds and vasculitis on autopsy.
Drugmaker Eisai said the company will price lecanemab at the wholesale acquisition cost of . Price watchdog ICER recently said lecanemab should be a year to be cost-effective.
Correction: An earlier version of this story reported that lecanemab's accelerated approval was supported by phase III data.