Lecanemab in Singapore: Appropriate use recommendations for early Alzheimer's disease

Introduction: Lecanemab, a monoclonal antibody targeting β-amyloid oligomers, protofibrils, and insoluble fibrils, has been approved for Alzheimer’s disease (AD) treatment in Singapore, based on the phase 3 Clarity AD study. In this paper, the Singapore-adapted Appropriate Use Recommendations (AURs) serve to assist Singapore physicians in identifying patients who will likely benefit from treatment while ensuring effective monitoring. Methods: The AURs are based on the Singapore-approved prescribing information combined with lecanemab phase 2 and 3 clinical trials and real-world data up to April 2026. Results: The decision to initiate lecanemab should be based on careful evaluation of individuals, including locally validated cognitive status tests to identify mild cognitive impairment (MCI) due to AD and mild AD dementia. Other important evaluations include baseline brain magnetic resonance imaging (MRI), assessment of the apolipoprotein E ε4 (APOEε4) genotype, and amyloid pathology confirmation. Guidance on identifying patients at increased risk of amyloid-related imaging abnormalities (ARIA) during treatment and other patient profiles warranting additional caution is provided. Recommendations for monitoring patients, managing infusion-related reactions, and identifying lecanemab discontinuation scenarios are included. Conclusion: Lecanemab should only be prescribed for patients with MCI due to AD or mild AD dementia following careful clinical evaluation confirming AD pathology, with caution exercised in patients at increased ARIA risk (e.g. APOEε4 gene carriers). During treatment, patients should receive regular monitoring for ARIA symptoms including follow-up MRI scans. Future directions include the development of a Singapore-specific registry to monitor patients and gather long-term data to support a consensus-driven framework to inform and optimise the use of lecanemab in Singapore.