89Zr-CTB006

89Zr-CTB006 is a radiolabeled humanized chimeric recombinant monoclonal antibody targeting death receptor 5 (DR5), labeled with the positron-emitting isotope zirconium-89. It acts as an agonistic antibody that specifically binds to DR5, a member of the tumor necrosis factor receptor superfamily involved in apoptosis signaling. The primary use of 89Zr-CTB006 is as a PET imaging agent for noninvasive detection and quantification of DR5 expression in tumors, particularly gastrointestinal cancers such as gastric and colorectal cancer. This allows for patient selection and monitoring in clinical trials evaluating DR5-targeted therapies[1][3][6][8]. The agent has shown high uptake in primary and metastatic tumor lesions with correlation to DR5 expression levels confirmed by RNAscope analysis[1][8]. Its biodistribution includes expected accumulation in blood, liver, spleen, and notably stable high uptake in adrenal glands[1][8].