A new paper "Treatment-related amyloid clearance (TRAC): a framework to characterize patients in the era of anti-amyloid therapies", led by Renaud La Joie, was just published in Alzheimer's & Dementia: The Journal of the Alzheimer's Association. Coauthors include Jeffrey Cummings, Jeffrey Dage, Douglas Galasko, Milos Ikonomovic, Thomas Karikari, Susan Landau, Jorge Llibre-Guerra, Catherine Mummery, Rik Ossenkoppele, Julie Price, Shannon Risacher, Ruben Smith, Chris Van Dyck, and Maria Carrillo.
This paper summarizes the discussion of a working group convened by the Alzheimer's Association, to
- come up with a nomenclature to describe patients who have received amyloid targeting therapies and show clearance of amyloid deposit as evidenced by PET
- summarize the literature on patients who show amyloid clearance
- identify gaps in knowledge.
The group proposes a terminology, treatment-related amyloid clearance (TRAC), to reflect alterations in disease pathophysiology defined by biomarker-defined pharmacodynamic changes, rather than direct neuropathological evidence. TRAC applies to individuals with (1) pretreatment biomarker confirmation of cerebral Aβ deposition, (2) treatment with an Aβ-targeting therapy, and (3) a follow-up biomarker test indicative of partial or full clearance of Aβ deposits. The workgroup currently recommends defining TRAC using amyloid-positron emission tomography (PET) and emphasizes the role of quantitative measurements for defining the degree of clearance. This encompasses two situations:
- Full TRAC, which describes individuals with amyloid-PET levels that have returned to the “negative” range.
- Partial TRAC, which describes participants whose amyloid-PET levels have significantly decreased with treatment but who remain above the predetermined positivity criterion.
