Donanemab in preclinical Alzheimer's disease: Screening and baseline data from TRAILBLAZER‐ALZ 3

TRAILBLAZER-ALZ 3 is investigating donanemab in preclinical Alzheimer's disease (AD). This double-blind, placebo-controlled trial used a plasma phosphorylated tau-217 (p-tau217) assay to detect AD pathology for eligibility and a decentralized design to enhance screening and enrollment. After nine monthly infusions, clinical assessments continue every 6 months with a time-to-event primary outcome. A sub-study will evaluate longitudinal changes in amyloid and tau positron emission tomography (PET). Participants 55-80 years of age were screened (N = 63,124). Plasma p-tau217-eligible participants were enrolled (N = 2196), with Clinical Dementia Rating (CDR) scale-Global score (CDR-GS) of 0 (n = 1202) and 0.5 (n = 664). Plasma p-tau217 eligibility increased with age, differing across races and ethnicities. Mean baseline amyloid levels were 63.2 (CDR-GS: 0) and 70.7 Centiloids (CDR-GS: 0.5). Elevated global tau signal (standardized uptake value ratio ≥1.10) was observed in 15.1% and 26.3% of CDR-GS 0 and 0.5 subgroups, respectively. Utilizing a unique decentralized design, the trial showed baseline data consistent with preclinical AD. ClinicalTrials.gov identifier: NCT05026866, TRAILBLAZER-ALZ 3 HIGHLIGHTS: TRAILBLAZER-ALZ 3 screened 63,124 participants in the United States and Japan Plasma phosphorylated tau-217 (p-tau217) was used to determine Alzheimer's disease pathology for eligibility A decentralized model was used, including remote raters for clinical testing Randomized participants had Clinical Dementia Rating scale-Global scores of 0 and 0.5.