Biodistribution and Kinetics of 18F-AraG in Non-Small Cell Lung Cancer

The overall goal of this project is to evaluate the ability of \[18F\]-AraG, a novel T-cell activation imaging biomarker, to measure T-cell activation before and after treatment with programmed death (PD) PD-1/PD-L1 inhibition and with PD-1/PD-L1 inhibition plus radiation therapy in NSCLC patients. Early preclinical and clinical studies have shown promise for immunotherapy treatments for several malignancies \[1\]. Immunotherapy is expected to grow in importance; however, it presents difficult challenges for response assessment. For instance, successfully treated tumors may actually increase in size after therapy due to inflammation and only later shrink \[2\]. RECIST criteria \[3\] designed to detect early effects of cytotoxic agents by size reduction, or the more recently proposed immune-related response criteria (irRC) \[4\] do not allow an early assessment of immunotherapeutic response since both depend on tumor size change. Furthermore, FDG PET is confounded by inflammatory effects causing hypermetabolism \[5\] \[6\]. Thus, it is imperative to develop new imaging and analysis protocols to evaluate immune-checkpoint blockade approaches. A method that evaluates T cell activation would permit an assessment of a basic first step in the process of assessing immunotherapy efficacy. There are two main goals associated with this project. We propose to 1) assess the \[18F\]-AraG biodistribution and kinetics, in non-small cell lung cancer (NSCLC) tumor(s) and tumor draining lymph nodes on \[18F\]-AraG PET/CT imaging before and after 1 course of immunotherapy and 1 course of immunotherapy plus radiation 2) correlate (potential) change in \[18F\]-AraG uptake within the tumor(s) or tumor draining lymph nodes with clinical and pathologic response in patients treated with immunotherapy.