After it granted an Accelerated Approval in January 2023, the U.S. Food and Drug Administration (FDA) fully approved Leqembi^® (lecanemab-irmb – Eisai/Biogen) on July 6, 2023. The first anti-amyloid monoclonal antibody to receive standard FDA approval for treating Alzheimer’s disease, Leqembi is administered at a dose of 10mg/kg once every two weeks by intravenous (IV) infusion. A boxed warning concerns a possible side effect that rarely results in intracerebral hemorrhages. For an individual who weighs 74kg (163 pounds) the wholesale acquisition cost (WAC) of Leqembi is about $26,500/year. It is distributed through one specialty pharmacy; Accredo does not have access. For revised prescribing information, please look here.

At a Glance

• Brand (Generic) Name: Leqembi^® (lecanemab-irmb)
• Manufacturer: Eisai/Biogen
• Date Approved: July 6, 2023
• Indication: to treat Alzheimer’s disease
• Dosage Forms Available: single-dose vials containing 200mg/2mL or 500mg/5ml of solution
• Estimated Annual Cost: $26,500 (WAC) for an individual weighing 74kg
• The most prevalent type of dementia, Alzheimer’s disease is estimated by the Alzheimer’s Association to affect more than six million people in the United States and diagnoses are expected to double over the next 30 years.
• Although its onset may be earlier for some individuals, Alzheimer’s disease symptoms generally begin around age 65 years – usually with forgetfulness and trouble making decisions.
• Over several years, brain function gradually deteriorates — leading to increased cognition difficulties, behavioral changes, and physical symptoms. Patients in advanced stages are unable to care for themselves.
• For reasons that currently are not understood, Alzheimer’s disease is caused by abnormal protein deposits in the brain. Accumulations of proteins known as amyloid beta plaques, damage brain cells and blood vessels. Tau proteins, which also build up in the brains of patients who have Alzheimer’s disease, twist nerve cells into distinctive “tangles”.
• By decreasing accumulations (plaques) of amyloid proteins in the brain, Leqembi slows down the advancement of Alzheimer’s for patients who have mild cognitive impairment or mild dementia along with confirmed amyloid plaques.
• In the 18-month-long trial, CLARITY AD, patients treated with Leqembi had significantly better scores on several measures of Alzheimer’s symptoms than patients given placebo infusions.
• The most common side effects from active treatment with Leqembi were headaches and infusion-site reactions.
• However, some of the patients who received Leqembi in the study experienced amyloid-related imaging abnormalities (ARIA) — about 13% had brain swelling (ARIA-E) and around 17% had tiny brain hemorrhages (ARIA-H) that may be associated with the use of treatments that alter amyloids. ARIA generally has no symptoms, but some patients who develop it have confusion, dizziness, nausea, or vision changes. Leqembi carries a boxed warning about the risks of ARIA.
• Additionally, the Centers for Medicare and Medicaid Services (CMS) is requiring prescribers to enter information on patients who are treated with Leqembi in national registries so that its effectiveness and safety can be tracked.
• Aduhelm^® (aducanumab-avwa – Biogen/Eisai) was the first amyloid beta monoclonal antibody to receive Accelerated Approval in June 2021 for treating Alzheimer’s disease. It has not yet been converted to full FDA approval.
• Eli Lilly and Company’s donanemab, another amyloid beta monoclonal antibody, also is under development to treat Alzheimer’s disease. In January 2023, the FDA asked for more complete clinical trial information from Lilly before considering the drug for Accelerated Approval. Part of the data was reported in May, but the FDA has not yet set an action date.

The FDA used its Fast Track, Priority Review, and Breakthrough Therapy processes to approve Leqembi.