On the 6th of January 2023 the Food and Drug Administration (FDA) approved Lecanemab-irmb through the accelerated approval pathway to treat Alzheimer’s disease. There has been rigorous efforts to combat this dreaded disease. Lecanemab is a second drug now approved for the treatment of Alzheimer’s disease. The first, named aducanumab, was earlier approved by FDA on the 7th of June 2021. The recent approval is a further step in addressing the life-threatening disease despite concerns over the potential side effects of the treatments.
Alzheimer’s disease is a life-threatening disorder that slowly destroys memory, thinking skills and other cognitive abilities. It is the most common type of dementia among older adults. The disease was named after Dr. Alois Alzheimer after he examined the brain of a woman who died of unusual mental illness. He observed many abnormal clumps (amyloid plaques) and neurofibrillary, or tau, tangles in the brain. The plaques and tangles are the main features of Alzheimer’s disease and leads to loss of neurons and neuronal connections. As a result, it affects the person’s ability to remember or even think. The initial lesions of the disease occur in the memory-related part of the brain (entorhinal cortex and hippocampus) and progressively extends to other parts of the brain responsible for language, reasoning, and social behaviors (like cerebral cortex). According to World Health Organization (WHO) more than 55 million people have dementia worldwide.
The newly approved drug also known as Leqembi evaluated in patients with mild cognitive impairment or mild dementia stage of the disease resulted in significant dose and time-dependent reduction of amyloid plague compared to those that received the placebo. Though risk concerns of deaths and side effects such as amyloid-related imaging abnormalities (ARIA), headaches, confusion, dizziness, vision changes, risk of hypersensitivity reactions have been raised, a new randomized, controlled clinical trial is expected to verify the clinical benefits of the drug. Accelerated approvals portend that the approval could be withdrawn if the expected controlled clinical trial fails to verify the clinical benefits of the drug.
Aducanumab which was earlier approved in 2021 by FDA is an amyloid beta-directed monoclonal antibody.
After FDA approved Lecanemab, another pharmaceutical company Eli Lilly recently conducted phase 3 trials for its own Alzheimer’s treatment candidate, donanemab. According to Eli Lilly “the monoclonal antibody donanemab slowed mental decline by 35% for some participants in a 1736-person trial” Like Lecanemab, donanemab targets amyloid protein, which are believed to cause dementia. The full result of this trial is yet to be made public. If the donanemab is approved by FDA, it will now be a third new drug for the treatment of Alzheimer’s disease within 24 months.
Further Reading:
https://www.nature.com/articles/d41586-023-00030-3
https://www.fda.gov/news-events/press-announcements/fda-grants-accelerated-approval-alzheimers-drug
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