Updated meta-analysis (MA) of salvage therapy for metastatic urothelial cancer (mUC): Comparing outcomes of immunotherapy (IT) versus single agent and doublet chemotherapy (CT).

Abstract

341 Background: Doublet CT demonstrated improved overall response rate (ORR) and progression-free survival (PFS) compared to single agent CT in a MA of patients (pts) receiving II line CT in trials of mUC ( Raggi et al, Ann Oncol 2016). We aimed to update the analyses adding trials of salvage IT. Methods: We searched for arms of phase 2 or 3 studies of salvage single agent anti-programmed cell death-1/Ligand-1 (PD-1/PD-L1) agents pembrolizumab, nivolumab, atezolizumab, durvalumab, avelumab, single agent CT and doublet CT. Random-effects models were used to pool trial level data according to treatment arm, including ORR, median PFS (mPFS), median overall survival (mOS). Univariable (UVA) and multivariable (MVA) analyses were performed, adjusting for ECOG-PS 2 and liver metastases. Results: 7 IT trials were analyzed (n=1,041), 22 arms received single agent CT (n=1,202), and 24 doublet CT (n=708). The pooled ORR was: 21.2% (95%CI: 14.9-29.2) with IT, 14.2% (95%CI: 11.1-17.9) with single agent CT and 31.9% (95%CI: 27.3-36.9) with doublet CT. Pooled mPFS was 1.8, 2.69 and 4.05 months, respectively. Pooled mOS was 8.27, 6.98 and 8.50 months. Pooled median ORR and mOS of IT for PD-L1+ pts were: 30.7% (95%CI: 23.2-39.2) and 11.60 months. Results of UVA and MVA are shown in the table. Only UVA was possible for PD-L1+ pts. Conclusions: Among trials of salvage therapy for mUC, IT was associated with significantly higher ORR and mOS in PD-L1+ pts compared with single agent or doublet CT, while significant differences were not seen in unselected pts. These results are hypothesis-generating and suggest the importance of developing companion predictive biomarkers. [Table: see text]