Evaluation of PD-L1 biomarker for immune checkpoint inhibitor (PD-1/PD-L1 inhibitors) treatments for urothelial carcinoma patients: A meta-analysis.

INTRODUCTION: Newly published results of clinical trials has demonstrated immune checkpoint inhibitors as robust antitumor agents for urothelial carcinoma patients. However, searching for predictive biomarkers is still on the way. Previous clinical trials used PD-L1 as biomarkers, however, whether it can predict the objective response rate and overall survival is controversial. This is the first and latest study to pool the newest data in order the evaluate PD-L1 biomarker.

RESULT: Nine studies were included and 1,436 urothelial carcinoma patients were included. We evaluated PD-L1 biomarker for atezolizumab, nivolumab, durvalumab, avelumab, and pembrolizumab treatments. Patients with higher PD-L1 expression have significantly higher objective response rate compared with the lower ones. PD-L1 predicted the one year overall survival of PD-L1 inhibitors but not PD-1 inhibitors. Only one year overall survival of durvalumab was significantly associated with PD-L1 expression.

CONCLUSION: PD-L1 can be used as a biomarker for objective response rate, while PD-L1 cannot predict the overall survival.