The Clinical Trials on Alzheimer’s Disease (CTAD) Advanced Workshop and Course in Azheimer’s Disease Clinical Trials, September 6-7, 2025, Shanghai, China, Oral communications

Background: We are conducting a multicenter, randomized, doubleblind, placebo-controlled event-driven Phase 3 trial (TRAILBLAZER-ALZ 3) using a decentralized clinical trial (DCT) approach to evaluate the efficacy of donanemab in preclinical AD (with evidence of AD pathology but without cognitive impairment).We present the screening/baseline characteristics at enrollment completion.Methods: Inclusion criteria are age 55-80, Modified Telephone Interview for Cognitive Status (TICS-m) score ≥35, and plasma P-tau217 results consistent with the presence of amyloid and early tau pathology.Results: We screened 63,124 participants using plasma P-tau217, enabling randomization of 2196 participants: US (n = 2137)/Japan (n = 59).The mean age was 70.2 years.Plasma P-tau217 (81.2%) and TICS-m (5.4%) were the main drivers of screen failure.P-tau eligibility increased with age.The median baseline TICS-m and Montreal Cognitive Assessment (MoCA) scores for a subgroup of participants with a baseline Clinical Dementia Rating-global score (CDR-GS) of 0 (CDR0) were 40 and 25, respectively, and 39 and 23 for participants with a baseline CDR-GS of 0.5 (CDR0.5).Conclusion: Enrolling participants in a preclinical AD study using a blood-based biomarker and a DCT approach is feasible.This cohort represents an earlier clinical and pathological stage compared with prior studies on early symptomatic AD, despite enrolling CDR0.5 participants.The outcome study is ongoing to assess donanemab treatment for slowing of progression to symptomatic AD.