89Zr-pembrolizumab

**89Zr-pembrolizumab** is a radioimmunoconjugate consisting of the humanized monoclonal antibody pembrolizumab (an IgG4 antibody targeting programmed cell death protein 1 [PD-1]) labeled with the positron-emitting radionuclide zirconium-89 (^89Zr). This compound is primarily used as an investigational PET imaging agent to non-invasively visualize and quantify the biodistribution and tumor uptake of pembrolizumab in vivo. The radiolabeling allows for tracking of the antibody's distribution in patients or animal models using PET/CT imaging. Mechanistically, it binds to PD-1 expressed on T cells and other immune cells, enabling assessment of target engagement and potentially predicting response to anti-PD-1 immunotherapy. It is not intended for therapeutic use but rather as a diagnostic or research tool in oncology—especially in cancers such as melanoma and non-small cell lung cancer (NSCLC)—to study pharmacokinetics, tissue distribution, tumor targeting efficiency, and immune-related effects[2][3][4][5][7].

Other names

zirconium-89-labeled pembrolizumabzirconium89-labeled pembrolizumabzirconium 89-labeled pembrolizumabZr-89 pembrolizumabZr89 pembrolizumabZr 89 pembrolizumab