FDA Approves New Dosing for Eli Lilly’s Kisunla to Reduce Brain Swelling; U.K. NHS Rejects Drug, EMA Recommends Approval; Leqembi Shows Four-Year Benefit

The U.K. health agency has determined that the Alzheimer's drugs Kisunla and Leqembi are not cost-effective and will therefore not be offered through the National Health Service (NHS). Meanwhile, the U.S. Food and Drug Administration (FDA) approved a new label update for Eli Lilly's Kisunla (donanemab-azbt), introducing a revised dosing schedule for patients in the early stages of Alzheimer's disease with mild symptoms. This updated dosing plan aims to reduce the risk of brain swelling, known as ARIA-E, lowering its incidence from 24% to 14% in a Phase 3 study while maintaining the drug's efficacy in amyloid plaque removal. Additionally, the European Medicines Agency (EMA) has recommended approval of Kisunla for certain early Alzheimer's patients, reversing an initial decision from four months prior. New clinical data presented at the Alzheimer's Association International Conference (AAIC) 2025 showed that Kisunla demonstrated growing benefits over three years in early symptomatic Alzheimer's disease. Similarly, Biogen and Eisai's Leqembi (lecanemab-irmb) therapy has shown continued benefit over four years, slowing clinical decline by 1.75 points on the Clinical Dementia Rating Scale Sum of Boxes (CDR-SB) compared to the natural history of the disease. A two-year real-world study of Leqembi in the U.S. was also presented at AAIC 2025. While both companies report ongoing benefits from their Alzheimer's therapies, they have differing views on the optimal duration of treatment.