Impact of C-reactive Protein Flare Response in Patients With Advanced Urothelial Carcinoma Who Received Pembrolizumab.

BACKGROUND/AIM To clarify the clinical significance of the temporary elevated C-reactive protein (CRP) levels followed by a decrease below baseline (CRP flare response) after administration of pembrolizumab to patients with advanced urothelial carcinoma (UC). PATIENTS AND METHODS We retrospectively reviewed 31 patients with advanced UC who received pembrolizumab. Patients were categorized into 3 groups (flare-responder, responder, non-responder) according to early CRP kinetics. Intergroup tumor response and survivals were compared. RESULTS Objective response rates of flare-responder, responder, and non-responder groups were 75%, 80%, and 26%, respectively. Median overall survival was not reached in flare-responder and responder groups, and was 10.2 months in the non-responder group (p=0.03). Furthermore, the flare-responder group did not reach median progression-free survival, and for the responder and non-responder groups it was 15.2 and 2.8 months, respectively (p=0.03). CONCLUSION CRP flare response might be a promising biomarker in patients with advanced UC who received pembrolizumab.