FDA approves breakthrough Alzheimer’s drug Lecanemab

The US Food and Drug Administration (FDA) has approved Lecanemab, a breakthrough drug to treat Alzheimer's, that is manufactured by biotechnology companies Biogen and Eisai.

The drug is an intravenously administered humanized monoclonal antibody that targets amyloid, the toxic protein in the brain linked to the cognitive disease.

Lecanemab, marketed as Leqembi, works with the body's immune system to clear amyloid protein buildup from the brain.

Dr Billy Dunn, the director of the Office of Neuroscience in the FDA's Center for Drug Evaluation and Research, said: "Alzheimer's disease immeasurably incapacitates the lives of those who suffer from it and has devastating effects on their loved ones. 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."

Findings from the clinical trial of the drug found that "Lecanemab reduced markers of amyloid in early Alzheimer's disease and resulted in moderately less decline on measures of cognition and function than placebo at 18 months but was associated with adverse events".

The most common side effects of the drug were infusion-related reactions, headaches and Aria (amyloid-related imaging abnormalities), which presents itself in the form of brain swelling and bleeding. Symptoms include headache, confusion, dizziness, vision changes, nausea and seizure. Some patients in the clinical trial experienced headaches, vision problems and confusion.

The significance of amyloid protein in Alzheimer's was first discovered by the British geneticist and molecular biologist Prof Sir John Hardy more than 30 years ago.

Upon detection of the amyloid protein in the brain, a physician may recommend Lecanemab to be administered, via a drip bag every two weeks.

Also under review is whether or not the drug will be covered by Medicare, the US government's national healthcare system for seniors - those most at risk for Alzheimer's.

Lecanemab must be priced lower than $20,600 a year to be cost-effective, according to the Institute for Clinical and Economic Review.

Few other drugs have been found to be successful in treating Alzheimer's. Another drug, Aducanumab, approved by the FDA in June 2021, is the first therapy to demonstrate that removing amyloid is likely to reduce decline in cognitive function. But approval of these drugs have faced criticism within the scientific community - largely to do with the speed at which they were approved.

The FDA approved both Aducanumab, which is marketed as Aduhelm, and Lecanemab on an accelerated timeline, both of which would normally take years to get approved.

The FDA offers fast-track approval to certain drugs with uncertain benefits if they are for serious diseases for which few treatments are available. Health experts argue there is no conclusive evidence Aducanumab slows down the neurological disease. Aducanumab costs $56,000 per year and Medicare does not cover the drug unless the patient is enrolled in an approved clinical trial.

The Alzheimer's Association filed a formal request in December last year, asking the Centers for Medicare and Medicaid Services to provide full and unrestricted coverage for FDA-approved Alzheimer's treatments.

Alzheimer's affects nearly 6.5 million Americans. In order to find out if someone is at risk for developing Alzheimer's, a positron-emission tomography (PET) scan can determine if the amyloid protein is present in the brain, but this can cost thousands of dollars and Medicare limits its coverage of these scans. A cerebrospinal fluid test, or "spinal tap", can detect the presence of the protein, but its painful and invasive nature deters many patients.