Alzheimer's drug Leqembi receives go ahead from the FDA to be used in patients

Eisai achieves FDA approval for it's Alzheimer's disease drug Leqembi, after rigorous testing in clinical trials show it reduces the size of characteristic plaques in the brains of patients. 

Leqembi is the brand name for the drug lecanemab-irmb, the second of such drugs to be approved for the treatment of Alzheimer’s by targeting the pathology of the disease, aiming to reduce the amyloid plaques in the brain that are inherent to the disease. 

“Alzheimer’s disease immeasurably incapacitates the lives of those who suffer from it and has devastating effects on their loved ones,” stated Billy Dunn, Director of the Office of Neuroscience in the FDA’s Centre 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.”

Leqembi was tested in a Phase III, double-blind, placebo-controlled, parallel-group, dose-finding study, which included 856 patients with Alzheimer’s disease, who had confirmed presence of amyloid beta plaques, identified using positron emission tomography (PET), and mild cognitive impairment. 

The test participants were given 10 mg/kg of lecanemab every two weeks. When compared to the control group at 79 weeks post start of treatment, the test subjects showed a statistically significant decrease in amyloid-beta plaques in the brain; the control group demonstrated no reduction in plaque build-up. 

These remarkable test results led to the accelerated approval of Leqembi, based on the reduction in plaques after PET in areas of the brain most likely to be affected. 

On prescription, Leqembi does come with a warning against amyloid-related imaging abnormalities (ARIA), which can develop with this class of antibodies. ARIA do not regularly give rise to symptoms, but serious and life-threatening adverse events have been known to occur, which did stir up concerns in the testing phase, but were mollified after further investigation. ARIA is commonly characterized by temporary swelling in the some areas of the brain and may also introduce small bleeds on the brain giving rise to symptoms such as headaches, confusion, dizziness, and seizure. The most common side-affects of Leqembi were headaches and ARIA. 

The approval of the drug only covers the specific use as was tested in the clinical trial, i.e patients with mild cognitive impairment or mild dementia stage of disease. There is currently no data to show whether there is any difference in safety or efficacy if the drug is used in patients at earlier or later stages of disease progression. This is something that will have to be elucidated in further clinical trials. 

Approval granted under Fast Track, Priority Review and Breakthrough Therapy designations is a big achievement in the ongoing battle to find effective treatments for Alzheimer’s disease and is a promising step for testing drugs in this class. 

For more big drug approvals to watch out for in 2023, see our recent article on the major drug approvals of recent times here.