1892P A pooled meta-analysis of salvage nivolumab/ipilimumab (N+I) after nivolumab (N) in patients with advanced renal cell carcinoma (RCC)

N+I has demonstrated improved survival for patients with treatment-naïve advanced clear cell RCC. A series of phase 2 trials (OMNIVORE NCT03203473; HCRN GU16-260 NCT03117309; TITAN-RCC NCT02917772) evaluated N+I in patients lacking an objective response to N. We performed a pooled meta-analysis of these studies to better inform the activity of N+I after N. Key baseline characteristics and outcomes were collected and analyzed centrally. The primary endpoint was confirmed objective response rate (ORR) to N+I as defined by investigator assessed RECIST v.1. Secondary endpoints included ORR to N, progression-free survival (PFS) rate from N+I start (only for OMNIVORE and HCRN GU-16-260), and overall survival (OS) rate from N start. The analysis included 448 patients of whom 410 (91.5%) had clear cell RCC, 369 (82.3%) had IMDC intermediate/poor risk disease, and 139 (31.0%) had prior treatment. The 16-18-week ORR to N prior to N+I was 21.9% (n=98) and best ORR to N was 24.1% (n=108). 249 (55.6%) patients treated with N received N+I at a median of 16 weeks (9-21 IQR) after initiation of N [26.1% (n=65) with stable disease (SD) to N and 73.9% (n=184) with progressive disease (PD) to N]. The ORR to N+I was 12.9% (n=32) (Table). Median follow-up was 34.2 months. 6-month PFS on N+I was 39% (95% CI 30-49). 3-year OS was 57% (95% CI 52-62) from N start. Table: 1892PORR to N+ISubgroupNORR (%)Overall24912.9Treatment naïve14512.4Prior therapy10413.5IMDC Favorable3915.4IMDC Intermediate16914.2IMDC Poor414.9Clear cell RCC23012.6Non-clear cell RCC1915.8Response to N at N+I Start – SD659.2Response to N at N+I Start – PD18414.1Best response to N – CR/PR2425.0Best response to N – Non-response22511.6 Open table in a new tab A small subset of patients lacking a response to N monotherapy derive benefit from salvage N+I. Additional correlative studies are warranted to investigate markers associated with benefit to N+I post N.