Treatment of Metastatic Disease with Immune Checkpoint Inhibitors Nivolumab and Pembrolizumab: Effect of Performance Status on Clinical Outcomes

INTRODUCTION: Although 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 whether there is a relationship between Eastern Cooperative Oncology Group (ECOG) performance status and outcomes of immunotherapy in patients treated for metastatic disease at our community-based oncology practice. METHODS: Patients (n = 253) were identified as receiving nivolumab or pembrolizumab for stage IV malignancy at Cancer Centers of Colorado, St. Joseph Hospital/SCL Health between June 2018 and November 2020. Patients who initiated therapy after May 2020 were excluded from analysis due to less than 6 months follow-up time. The remaining 183 patients were included in a retrospective cohort study comparing patients with ECOG 0, 1, and 2–4. Sex, age, type of cancer, line of therapy, time on therapy and best response to therapy were determined. These baseline factors and outcomes were compared using analysis of variance (ANOVA) for numeric variables and χ(2) tests of association for categorical variables. Time from initiation of ICI to death or hospice was also compared using a log-rank test as well as a multivariate Cox proportional hazards model. RESULTS: Of the 183 patients included, 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. Sex and line of therapy did not differ between groups. There was a significant difference in age, with mean age of 62, 66, and 70 in ECOG 0, 1, and 2–4, respectively. Patients (54.6%) remained on therapy for at least 6 months, with no significant difference between groups in ability to complete 6 months of therapy. For ECOG 0, 1, and 2–4, disease control was achieved in 67.2%, 59.6%, and 41.7%, respectively. Analysis of time to death or hospice with a log-rank test showed a significant difference between groups. A multivariate Cox proportional hazards model revealed that patients with ECOG 0 had significantly longer time to death or hospice compared with patients in both other groups after controlling for age, sex, and line of therapy. CONCLUSION: 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.