Plasma P-tau217 for detecting amyloid clearance after donanemab in Alzheimer's disease
In brief
Plasma p-tau217 detects amyloid clearance after donanemab with only modest accuracy
In the TRAILBLAZER-ALZ 2 phase 3 trial, plasma p-tau217 measured at 52 weeks identified PET-confirmed amyloid clearance (below 24.1 Centiloids) with an area under the ROC curve of 0.61, indicating suboptimal performance. Although donanemab lowered p-tau217 levels, the test cannot yet replace PET for monitoring treatment response in early symptomatic Alzheimer disease.
- Journal
- Alzheimer's & dementia : the journal of the Alzheimer's Association (Q1)
- Published
- 1 August 2026
- Study design
- Randomized controlled trial
- Evidence level
- Level 1, High (CEBM 1b)
- Authors
- Emily C Collins, Ming Lu, Rose Beck, James Hendrix, Michael E Hodsdon, Oskar Hansson
- PMID
- 42565262
- DOI
- 10.1002/alz.71740
Why clinicians should know about it
- Picked for Radiology, Radiation Oncology, Nuclear Medicine, Medical Physics and Imaging (top studies of the week, 9 August 2026): Plasma p‑tau217 for amyloid clearance, no imaging endpoint
Abstract
INTRODUCTION: This analysis of the phase 3 TRAILBLAZER-ALZ 2 trial examined whether plasma tau protein phosphorylated at threonine 217 (p-tau217) level can reliably monitor treatment-related amyloid clearance (TRAC) after donanemab treatment in early symptomatic Alzheimer's disease (AD). METHODS: Amyloid positron emission tomography (PET) and plasma p-tau217 levels were assessed at baseline and longitudinally during study treatment. The diagnostic performance of p-tau217 in detecting post-treatment TRAC (< 24.1 Centiloids [CL]) was evaluated by receiver operating characteristic (ROC) analysis. RESULTS: Plasma p-tau217 showed suboptimal performance in detecting TRAC by PET in donanemab-treated participants (N = 830), with an area under the ROC curve of 0.61 at 52 weeks. DISCUSSION: Despite reductions in plasma p-tau217 with donanemab treatment, this biomarker cannot currently be used to accurately detect TRAC by PET (< 24.1 CL) in individuals with early symptomatic AD.
Abstract as published, via PubMed.
For healthcare professionals. The summary is generated by AI from the published abstract, and the evidence level is assigned automatically from the study design on the Oxford CEBM hierarchy. Neither is medical advice. Read the full paper before changing practice.