Circulating cell populations as response predictors and targets to improve immunotherapy in metastatic lung cancer

The effectiveness of immunotherapy varies among patients with advanced non-small cell lung cancer (NSCLC). Here we investigated the baseline immune status in stage IV NSCLC patients treated with anti-PD-1 plus chemotherapy to understand the immune mechanisms and unveil systemic markers associated with treatment response. Responders had elevated frequencies of circulating T cells expressing CD69, TCF-1 and CXCR-3. In contrast, non-responders presented increased frequencies of CTLA-4, CD161 and IL-10 expressing CD4+ and CD8+ T cells. These systemic T cell immune profiles were mirrored in the tumor microenvironment of an independent cohort. Concurrent CTLA-4 and PD-1 blockade was able to reactivate an anti-tumor profile in T cells from non-responder patients, emphasizing the pivotal role of CTLA-4 in contributing to an immunosuppressive environment that hinders effective treatment in NSCLC. This work supports the implementation of personalized immunotherapies based on systemic immune biomarkers, offering a promising approach to enhance treatment outcomes in advanced NSCLC.