The European Medicines Agency (EMA) has partially approved Leqembi (lecanemab), a new treatment for Alzheimer's disease, reversing an earlier decision. The approval is contingent on the drug being used for patients with mild cognitive impairment or mild dementia due to Alzheimer's who have one or no copies of the ApoE4 gene, a known risk factor. This decision follows concerns about side effects, including potential brain bleeding, which led to the initial rejection.
Leqembi's Mechanism and Clinical Impact
Leqembi, developed by Biogen and Eisai, targets the underlying cause of Alzheimer's by using antibodies to bind to and clear amyloid proteins that accumulate in the brain. Clinical trials have demonstrated that the treatment can decrease cognitive decline by approximately 25% in individuals in the early stages of the disease. This represents a significant advancement, as previous treatments primarily focused on managing symptoms rather than addressing the disease's progression.
Risk Mitigation and Monitoring
The EMA's endorsement includes specific risk minimization measures to mitigate the potential for severe and symptomatic amyloid-related imaging abnormalities (ARIA), such as fluid on the brain and brain bleeding. These measures include a controlled access program to ensure the medicine is used only in the recommended patient population and MRI scans before and during treatment to monitor for ARIA. The EMA emphasized that the benefits of Leqembi outweigh the risks in the specified patient group, provided these risk minimization measures are in place.
Regulatory Landscape and Future Steps
Britain's medicines regulator approved lecanemab in August, making it the country's first such licensed treatment. Leqembi, along with Aduhelm, previously received approval from the US Food and Drug Administration. The EMA's approval will now be sent to the European Commission for a final decision to roll it out across the continent. Pricing and reimbursement decisions will be determined by individual member states.
