Definition

A radioimmunoconjugate composed of TAK-164, an antibody-drug conjugate (ADC) comprised of a full-length, human immunoglobulin G1 (IgG1) monoclonal antibody (mAb) directed against the extracellular domain of guanylyl cyclase C (GCC; GUCY2C) conjugated to the DNA alkylator DGN549 (IGN-P1), and linked to the radioisotope zirconium Zr 89 (Zr89), with potential use in imaging of GCC-expressing tumor cells upon positron emission tomography (PET). Upon administration of zirconium Zr 89-TAK-164, the TAK-164 moiety targets and binds to GCC. After binding, Zr89 facilitates the visualization and detection of GCC-expressing tumor cells using PET. This assesses GCC-expression and may predict or evaluate the tumor’s response to TAK-164.