[18F]ABBV-964i

[18F]ABBV-964i is a novel fluorine-18 labeled positron emission tomography (PET) radiopharmaceutical developed by AbbVie in collaboration with Invicro. It is specifically designed as a high-affinity ligand for 4-repeat (4R) tau protein isoforms. In neurodegenerative diseases such as progressive supranuclear palsy (PSP) and corticobasal degeneration (CBD), tau protein aggregates primarily into 4R isoforms, distinct from the mixed 3R/4R aggregates found in Alzheimer's disease. [18F]ABBV-964i allows for the non-invasive visualization and quantification of these 4R tau deposits in the brain, serving as a critical biomarker for diagnosis, disease staging, and the evaluation of tau-targeting therapies in clinical trials.