Clinical outcome of patients (Pts) with metastatic renal cell carcinoma (mRCC) progressing on front-line immune-oncology based combination (IO-COMBO) regimens.

613Background: Several IO-COMBO regimens are under investigation in front-line mRCC. The clinical outcome of pts who progress on an IO-COMBO regimen and receive subsequent systemic therapy is unknown. Methods: A retrospective analysis of all pts with clear-cell mRCC enrolled in one of seven clinical trials investigating an IO-COMBO at Cleveland Clinic Taussig Cancer Institute and Barts Cancer Institute was conducted. Clinical outcome of subsequent therapy including best objective response according to RECIST v1.1, progression-free survival (PFS) and adverse events (AEs) using CTCAE v4.0, were collected. Results: From a total of 89 pts enrolled on an IO-COMBO trial, final analysis included 32 pts with PD who received ≥1 line of subsequent therapy, median age 57 (41-77), 83% male, 72% ECOG 0, 78% IMDC fav-/intm- risk. Prior IO-COMBO included atezolizumab/bevacizumab (n = 20), ipilimumab/nivolumab (n = 10) and axitinib/avelumab (n = 2). All except 1 pt received IO-COMBO in the front-line setting. All pts rec...