Effect of cyclo-oxygenase inhibitor use during checkpoint blockade immunotherapy in patients with metastatic melanoma and non-small cell lung cancer

Background Immune checkpoint inhibitors (ICIs) improve survival outcomes in metastatic melanoma and non-small cell lung cancer (NSCLC). Preclinical evidence suggests that overexpression of cyclo-oxygenase-2 (COX2) in tumors facilitates immune evasion through prostaglandin E2 production and that COX inhibition synergizes with ICIs to promote antitumor T-cell activation. This study investigates whether concurrent COX inhibitor (COXi) use during ICI treatment compared with ICI alone is associated with improved time-to-progression (TTP), objective response rate (ORR) and overall survival (OS) in patients with metastatic melanoma and NSCLC. Methods We retrospectively reviewed 90 metastatic melanoma and 37 metastatic NSCLC patients, treated with ICI between 2011 and 2019. Differences in TTP and OS by ICI+COXi versus ICI alone were compared using Kaplan-Meier and Cox regression. Interaction between ICI+COXi versus ICI alone and pretreatment neutrophil-lymphocyte ratio (NLR) was examined. Independent radiology review per Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1 was performed. Results For patients with melanoma, median TTP was significantly prolonged in ICI+COXi versus ICI alone (245 vs 100.5 days, p=0.002). On multivariate analysis, ICI+COXi associated with increased TTP (HR 0.36, 95% CI 0.2 to 0.66, p=0.001), adjusted for age, pretreatment NLR, and gender. For NSCLC patients, ICI+COXi also associated with increased TTP compared with ICI alone on multivariate analysis (HR 0.45; 95% CI 0.21 to 0.97; p=0.042) adjusted for age. ORR at 6 months was significantly higher in patients who received ICI+COXi compared with ICI alone in both melanoma (58.6% vs 19.2%, p=0.0005) and NSCLC (73.7% vs 33.3%, p=0.036) cohorts. In the melanoma cohort, high pretreatment NLR (>5) associated with decreased TTP (HR 3.21, 95% CI 1.64 to 6.3; p=0.0007); however, ICI+COXi significantly associated with increased TTP in high NLR (>5) patients (HR 0.08, 95% CI 0.03 to 0.25), but not in low NLR (<= 5) patients (HR 0.65, 95% CI 0.32 to 1.32). Similar outcomes were found in an adjusted melanoma cohort after RECIST review. Conclusions Our study suggests that COXi use concurrently with ICI significantly associated with longer TTP and improved ORR at 6 months in patients with metastatic melanoma and NSCLC compared with ICI alone. Furthermore, COXi use appears to reverse the negative prognostic effect of a high NLR by prolonging TTP in patients with melanoma.