The U.S. Food and Drug Administration (FDA) announced Thursday that it had approved the new Alzheimer’s drug Leqembi (lecanemab-irmb) after a confirmatory trial verified its clinical benefit. As a result, the expensive treatment should be included in Medicare — the federal health insurance program for Americans over 65 and younger people with disabilities — which will pave its access to millions of patients. The FDA added that a boxed warning will alert patients and caregivers of the drug’s potential risks.
Leqembi is the first amyloid beta-directed antibody to be converted from an accelerated approval — which it received in June — to a traditional approval for the treatment of Alzheimer’s disease. The drug works by reducing amyloid plaques that form in the brain, a defining pathophysiological feature of the disease.
Leqembi was approved in January under the Accelerated Approval pathway, which is used for drugs for serious conditions where there is an unmet medical need. According to an FDA statement, this decision was based on clinical data that demonstrated that it is “reasonably likely to predict a clinical benefit to patients.” As a subsequent requirement, the FDA demanded that a confirmatory study be carried out. The results of this trial showed Leqembi’s effectiveness in modestly slowing down the progression of Alzheimer’s.
The FDA, however, decided to include a warning on the drug’s label due to the risk of “serious and life-threatening brain edema.” “Intracerebral hemorrhages can occur in patients treated with this class of medications and can be fatal,” it said in the press release announcing the drug’s full approval.
The FDA explained that the most common side effects of Leqembi are headaches, infusion-related reactions and amyloid-related imaging abnormalities (ARIA), a side effect known to occur with the class of antibodies targeting amyloid. ARIA most commonly presents as temporary swelling in areas of the brain seen on imaging studies that usually resolves over time and may be accompanied by small spots of bleeding in or on the surface of the brain. Although ARIA is often not associated with any symptoms, symptoms can occur and include headache, confusion, dizziness, vision changes and nausea. ARIA can also infrequently present with serious and life-threatening brain edema that can be associated with seizures and other severe neurological symptoms.
Alzheimer’s disease is an irreversible and progressive brain disorder that affects more than 6.5 million Americans. The disease slowly destroys memory and thinking skills and, over time, the ability to carry out simple tasks. Although the specific causes of Alzheimer’s are not fully understood, it is characterized by changes in the brain— including the formation of amyloid beta plaques and neurofibrillary, or tau, tangles — that result in the loss of neurons and their connections.
“Today’s action is the first verification that a drug targeting the underlying disease process of Alzheimer’s disease has shown clinical benefit in this devastating disease,” said Teresa Buracchio, acting director of the Office of Neuroscience in the FDA’s Center for Drug Evaluation and Research. “This confirmatory study verified that it is a safe and effective treatment for patients with Alzheimer’s disease.”
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