Molecular Imaging Using Radiolabeled Atezolizumab to Assess Atezolizumab Biodistribution in Lymphoma Patients

Molecular imaging can be used for the noninvasive assessment of biodistribution of monoclonal antibodies. Atezolizumab has previously successfully been labeled with the radionucleotide Zirconium-89 (89Zr) and studied in solid malignancies (NCT02453984). The results of atezolizumab biodistribution can help to get a better understanding of the response mechanisms, the relation with minimal residual disease, the relation with the status of the T-cell and natural killer (NK)-cell repertoire and toxicity of programmed death ligand 1 (PDL1) checkpoint inhibition. Possibly in the future this will facilitate optimal patient selection. Sequential 89Zr-atezolizumab positron emission tomography (PET) scans can provide information on the dynamics of atezolizumab biodistribution over time. In combination with repeated characterization of tumor tissue and blood samples, these results can give inside in primary and acquired resistance. In this parallel study of the HOVON 151 trial, 89Zr-atezolizumab-PET-scans will be used to evaluate 20 high risk DLBCL patients before and after induction (R-CHOP) therapy, and at suspected relapse during or after atezolizumab consolidation (HOVON 151).