Treatment of metastatic disease with immune checkpoint inhibitors nivolumab and pembrolizumab: Effect of performance status on clinical outcomes.

Abstract

e18689 Background: While guidelines exist for appropriate use of chemotherapy in the metastatic setting based on performance status, such recommendations are less readily available for immune checkpoint inhibitors (ICIs). We sought to determine if there is a relationship between Eastern Cooperative Oncology Group (ECOG) performance status and outcomes on immunotherapy in patients treated for metastatic disease at our community-based oncology practice. Methods: 253 patients were identified as receiving nivolumab or pembrolizumab for stage IV malignancy at Cancer Centers of Colorado-SCL Health, between June 2018 and November 2020. Patients initiated on therapy after May 2020 were excluded from analysis, due to insufficient (less than 6 months) follow-up time. The remaining 183 patients were included in a retrospective cohort study comparing patients with ECOG 0, ECOG 1, and ECOG 2-4. Sex, age, type of cancer, and line of therapy were collected. Time on therapy was also calculated. Best response to therapy was determined (disease control or progressive disease). These baseline factors and outcomes were compared using ANOVA for numeric variables and chi-square tests of association for categorical variables. Time from initiation of ICI to death or hospice was also investigated and compared using a log-rank test. In addition, a multivariate Cox proportional hazards model was developed for the outcome, time to death/hospice, versus the predictors ECOG status, age, gender, and line of therapy. Hazard ratios (HR) and 95% confidence intervals (CI) were estimated. Results: Of the 183 patients included in analysis, 31.7% had an ECOG of 0, 48.6% an ECOG of 1, and 19.7% an ECOG of 2-4. Non-small cell lung cancer and melanoma represented the majority of patients in each group. Gender and line of therapy did not differ between groups. There was a significant difference in age (p = 0.02) with mean age 62, 66, and 70 in ECOG 0,1, and 2-4, respectively. 54.6% of patients remained on therapy for at least 6 months (182 days), and there was no significant difference between groups in ability to complete 6 months of therapy (p = 0.32). For ECOG 0, 1, and 2-4, disease control was achieved in 67.2%, 59.6 %, and 41.7%, respectively (p = 0.048). Analysis of time to death/hospice with a log rank test and Kaplan Meier plot showed a significant difference between groups (p < 0.001). A multivariate Cox proportional hazards model revealed that patients with ECOG 0 had significantly longer time to death/hospice compared to patients in both other groups, after controlling for age, gender, and line of therapy (ECOG 1 vs. 0: HR 2.5, CI 1.27-4.9; ECOG 2-4 vs. 0: HR 2.83, CI 1.31-6.13). Conclusions: In this single institution retrospective study of patients receiving nivolumab or pembrolizumab for metastatic cancer, ECOG 0 was associated with disease control and increased time before death or transition to hospice.