Early Serum and Hematological Responses to Pembrolizumab Therapy as Predictors of Survival in Metastatic Urothelial Cancer

In order to search for predictive biomarkers of efficacy of pembrolizumab therapy for metastatic urothelial cancer (UC), we investigated the relationship between treatment outcomes and early neutrophil-lymphocyte ratio (NLR), lactate dehydrogenase (LDH), and C-reactive protein (CRP) responses.Medical records of 101 patients with metastatic UC who started pembrolizumab as a second-line or later treatment were reviewed. NLR, LDH, and CRP were recorded after 3 weeks of therapy. In addition, we investigated whether these factors had an association with prolonged progression-free (PFS) or overall (OS) survival.The objective response rate, median PFS, and median OS were 25.7%, 6.3 months, and 15.2 months, respectively. PFS and OS were significantly shorter in patients with NLR3, LDHupper limit of normal (ULN), and CRP0.5 mg/dl after 3 weeks of pembrolizumab treatment (p0.05). A predictive model comprising these factors (favorable risk group: 0 risk factors; intermediate-risk group: 1-2 risk factors; poor-risk group: 3 risk factors) revealed distinct PFS and OS curves (p0.001). In the favorable risk group, 12-month OS was 79.6%; in the poor-risk group, it was 12.8%. Harrell's C-indices for NLR3, LDHULN, CRP0.5 mg/dl, and all three combined for predicting OS were 0.656, 0.625, 0.633 and 0.678, respectively. Early responses were also non-significantly associated with ORR (p=0.37).Pembrolizumab treatment outcomes are associated with early NLR, LDH, and CRP responses in metastatic urothelial cancer.