Comparison of objective response rate and long-term overall survival in patients with treated immune checkpoint inhibitors in metastatic urothelial carcinoma.

Abstract

481 Background: In this study, we evaluated RECIST criteria-based objective response rate (ORR) as potential surrogate endpoints for overall survival (OS) in patients who were treated with immune checkpoint inhibitors therapy (ICT) and with long-term follow-up in metastatic urothelial carcinoma. Methods: The primary endpoint was overall ORR and OS, duration of treatment (DOR) with ICT. ORR was analyzed using Fisher’s exact test. Median follow-up and OS were estimated by using the Kaplan-Meier method. Results: The median follow-up time was 58 (1.15–71) months (mo). Progression developed in 94 (47%) patients during the first three months of treatment with ICT. The rate of complete response (CR) to ICT, partial response (PR) rate, and stable disease were 10% (n=20), 23% (n=46), and 20% (n=41), respectively. There was an imbalance in baseline characteristics between patients who had ORR and non-responder groups (Table). The 5–year OS rates for CR and PR were 73% and 23%, respectively. The median DOR for CR, PR, and SD were 51.8 mo% (44.5–59.1), 20.7mo (16.7–24.6), and 8.8 mo (5.5–12.1), respectively. Of the sixteen (80%) patients who had CR and 14 (30%) patients who had PR had an ongoing response at the time of the analysis. In univariate analysis, neutrophil-to-lymphocyte ratio (NLR) >3, liver metastases, ECOG PS ≥1, and hemoglobin levels below 10 mg/dl, PR, and CR were all significantly associated with OS. In multivariate analysis, liver metastases [HR=2.3; 95% CI 1.3-4.2; p < (0.004)] were independent related variable with short OS. Other hand, PR [HR=0.3; 95% CI 0.15-0.5; p < (0.001)] and CR [HR=0.06; 95% CI 0.014-0.27; p < (0.001)] were associated with improved OS. Conclusions: This five-year analysis of real-world data indicated a significant correlation between ORR, especially CR and OS in patients who received immune checkpoint inhibitors in metastatic urothelial cancer. Therefore, the identification of a potential surrogate marker for survival in patients treated with ICT would represent an important advance in the early identification of patients’ response or resistance to ICT.