[64Cu]N3-PEG3-WX360-Nle

[64Cu]N3-PEG3-WX360-Nle is a copper-64 ([64Cu])-labeled cyclic peptide-based positron emission tomography (PET) radioligand targeting the urokinase-type plasminogen activator receptor (uPAR). Developed by the National Institutes for Quantum Science and Technology (QST) in Japan, the radioligand is designed based on the uPA-derived peptide WX-360-Nle, which binds to uPAR domain I. It is conjugated with a PEG3 linker and an azide (N3) group to improve stability and pharmacokinetics. In preclinical studies, [64Cu]N3-PEG3-WX360-Nle demonstrated high stability, specific binding to uPAR-positive B16F10 melanoma cells, rapid clearance from normal tissues, and superior tumor-to-background contrast compared to its non-azide counterpart, supporting its potential use for noninvasive PET imaging of uPAR expression in various cancers.