Eisai and Biogen have presented new real-world findings at the 20th International Conference on Alzheimer’s and Parkinson’s Diseases in Denmark showing that most patients receiving intravenous Leqembi (lecanemab), an anti‑amyloid‑β (Aβ) protofibril antibody, continued with the treatment after the initial 18-month study.
Of the patients who completed the 18 months of Leqembi treatment in the phase 3 Clarity AD study, 94% chose to continue maintenance treatment by enrolling in the open-label long-term extension (OLE) study.
In the OLE of Clarity AD study, patients continue to benefit from four years of Leqembi treatment compared with the natural course of Alzheimer’s disease (Alzheimer’s Disease Neuroimaging Initiative: ADNI*).
The study included 10,763 people who met the requirement for continuous healthcare encounters, out of the 13,388 individuals recorded in the database who received at least one intravenous treatment with lecanemab between 6 January 2023 and 30 November 2025.
The average age of patients was 73.8 years and 56.5% were female. The most common comorbidities were dyslipidemia (42.2%) and hypertension (36.9%).
*ADNI is a clinical research project launched in 2005 to develop methods to predict the onset and progression of AD and to confirm the effectiveness of treatments. The project involves a multi-year longitudinal observation targeting healthy elderly individuals as well as patients with mild cognitive impairment (MCI) and early stages of AD.