Predictive biomarkers of radio-immunotherapeutic response in NSCLC

Metastatic non-small cell lung cancer (mNSCLC) is the leading cause of cancer-related death in the United States. Most patients with mNSCLC are treated with systemic agents, which prolong survival and improve symptoms, but are typically not curative. Although recent advancements in immune checkpoint inhibitors have revolutionized the management of mNSCLC lacking targetable driver mutations, only a fraction of mNSCLC patients benefit from immunotherapy. Emerging evidence suggests that ablative radiotherapy can augment immunotherapy responses in metastatic disease; however, strategies to optimize the synergy between local radiation and the immune system are not well defined. We are conducting a randomized phase I/II clinical trial designed to evaluate the safety and efficacy of combination immune checkpoint blockade (ipilimumab + nivolumab) plus multisite ablative radiotherapy as a first-line treatment for patients with mNSCLC. As a secondary analysis of the phase I trial, we propose to investigate biomarkers associated with treatment response. In Aim 1, we propose to compare the diagnostic accuracy of established clinical biomarkers, including PD-L1 immunohistochemistry (IHC), tumor mutational burden, gene expression profiles, and multiplex IHC in predicting response to combination ablative radiotherapy and immunotherapy. In Aim 2, we propose to characterize global transcriptional and genomic changes induced by radiation when given prior to or concurrently with immunotherapy and evaluate whether these changes are associated with treatment response. In addition, in Aim 3, we propose to validate a novel biomarker derived from alternative splicing as a predictor of radio-immunotherapy response. By elucidating the immunomodulatory properties of radiotherapy, we may be able to improve treatment responses and long-term survival in patients with mNSCLC.