64Cu-CB-TE2A-GEEE-ZHER2:342

64Cu-CB-TE2A-GEEE-ZHER2:342 is a radiopharmaceutical diagnostic agent designed for positron emission tomography (PET) imaging of HER2-expressing tumors. It consists of a high-affinity HER2-targeting Affibody molecule (ZHER2:342) conjugated to the cross-bridged chelator CB-TE2A (1,4,8,11-tetraazacyclotetradecane-1,8-diacetic acid) via a negatively charged Gly-Glu-Glu-Glu (GEEE) peptide spacer, and labeled with the positron-emitting radioisotope Copper-64 (64Cu). The incorporation of the GEEE spacer is a critical design feature intended to optimize the biodistribution profile by significantly reducing hepatic uptake and enhancing the tumor-to-organ contrast compared to non-spaced or differently spaced variants. This molecular design aims to improve patient stratification for HER2-targeted therapies by providing high-contrast imaging with low background noise in normal tissues.