The long-term goal of this research is to identify clinical strategies to manage adverse events during checkpoint inhibitor therapy. The research aims of the current project are (1) to determine the impact of checkpoint inhibitor therapy on the metabolism of CYP probe drugs and the risk for adverse events with CYP substrate drugs commonly prescribed to cancer patients and (2) to identify associations between pro-inflammatory cytokine concentrations and CYP probe drug metabolism before and during checkpoint inhibitor therapy. To investigate these aims, we plan to conduct a two-phase crossover clinical drug interaction study in which a cocktail containing probe drugs for six CYP enzymes (CYP1A2, CYP2B6, CYP2C9, CYP2C19, CYP2D6, and CYP3A) is administered to subjects before and after they initiate checkpoint inhibitor therapy. However, the kinetics of changes in pro-inflammatory cytokines during checkpoint inhibitor therapy are not well established, and this knowledge is critical to inform timing of the on-treatment phase of the clinical drug interaction study. Accordingly, this pilot study will investigate when blood concentrations of pro-inflammatory cytokines peak after initiation of checkpoint inhibitor therapy. Blood cytokine concentrations will be assayed at baseline, ~7 and ~14 days following the first checkpoint inhibitor cycle (± 2 days surrounding each timepoint), and at cycles 2, 3, and 4 based on the strongest current in vitro (7-14 days) and clinical evidence (21-42 days). In addition to plasma concentrations of pro-inflammatory cytokines, the study will also assay plasma concentrations of immune checkpoint inhibitors, co-administered CYP substrates, and perform genetic sequencing to assess associations between these variables and clinical outcomes, including the development of immune-related adverse events, the potential for drug-drug interactions with CYP substrates, and checkpoint inhibitor treatment response.
This research aims to identify clinical strategies to manage adverse events during immune checkpoint inhibitor therapy by (1) determining the impact of checkpoint inhibitors on metabolism through major CYP enzymes and (2) identifying associations between pro-inflammatory cytokine concentrations and negative clinical outcomes during checkpoint inhibitor therapy.