Circulating cytokine associations with clinical outcomes in melanoma patients treated with combination nivolumab plus ipilimumab.

Nivolumab plus ipilimumab (aCTLA-4/aPD-1) combination therapy has significantly improved clinical outcomes in patients with metastatic melanoma, with 50%-60% of patients responding to treatment, but predictors of response are poorly characterized. We hypothesized that circulating cytokines and peripheral white blood cells may predict response to therapy and evaluated 15 cytokines and complete blood counts (CBC with differentials) from 89 patients with advanced melanoma treated with combination therapy from three points in time: pre-treatment, one month and approximately three months after starting therapy. Clinical endpoints evaluated included durable clinical benefit (DCB), progression-free survival (PFS), and overall survival (OS). A parsimonious predictive model was developed to identify cytokines predictors of response to combination therapy. In this study, we found that pre-treatment, patients with DCB had higher IL-23, lower CXCL6, and lower IL-10 levels. Lower NLR one month after starting therapy predicted better PFS and OS, primarily driven by an increase in absolute lymphocytes. A multivariate model demonstrated that baseline CXCL6, IL-10, IL-23 were independent predictors of therapy response, and the combined model has reached an area under the curve (AUC) of 0.79 in prediction of response to combination therapy. Our study identified baseline CXCL6, IL-23, and IL-10 as predictors of response to aCTLA4/aPD1 combination therapy among patients with metastatic melanoma. This study also provides a framework for identifying patients who are likely to respond to combination ICB, as well as a subset of patients with high risk of developing resistance and are thus in need of alternative therapeutic options, such as clinical trials.