UC Davis

INTRODUCTION: Monoclonal antibodies (mAbs) for Alzheimer's disease (AD) represent major therapeutic advances, but their economic value is uncertain. This review narratively examines cost-effectiveness analyses (CEAs) of aducanumab, lecanemab, and donanemab for early-onset AD. METHODS: We searched Medline (via PubMed) and EMBASE in April 2026 and incremental cost-effectiveness ratio (ICER) reports for CEAs of these mAbs. Inclusion required sufficient data to calculate ICERs. Two reviewers independently screened studies, and risk of bias was assessed using Risk of Bias in Systematic Reviews. Data were synthesized narratively due to methodological heterogeneity. RESULTS: Of 755 records screened, 16 CEAs met inclusion criteria (six aducanumab, eight lecanemab, one aducanumab/donanemab, one lecanemab/donanemab). Almost all aducanumab studies reported ICERs that exceeded commonly cited US willingness‑to‑pay thresholds (e.g., $100,000-$150,000 per quality-adjusted life year [QALY]), with ratios ranging from $127,461 to $1,581,276/QALY (2026 USD). Lecanemab results were mixed, with manufacturer‑funded models reporting ICERs below commonly cited thresholds, while other models generally exceeded them. The single donanemab analysis versus standard of care reported an ICER of $214,760/QALY (2026 USD), above commonly cited thresholds, and a Brazilian analysis comparing donanemab with lecanemab reported an ICER of $1,477,604/QALY (2026 USD). No independent study found any mAb cost savings. DISCUSSION: ICER variability across studies, despite reliance on the same clinical trials, reflects sensitivity to assumptions and potential sponsorship bias. Evidence is limited by small numbers of CEAs, reliance on modeled rather than real-world data, and absence of formal risk-of-bias scoring for individual CEAs. The cost-effectiveness of AD mAbs in the US context remains uncertain.