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.