LAUSR

659 Background: Ipi/Nivo is a standard of care for pts with metastatic clear cell RCC. The clinical activity of Ipi/Nivo in patients with metastatic nccRCC remains poorly defined. Methods: Metastatic nccRCC pts who were treated with Ipi/Nivo at Cleveland Clinic or UT Southwestern were retrospectively reviewed. Ipi/Nivo was administered as per CHECKMATE 214. Computed tomography imaging was obtained at baseline and every12 weeks to assess disease response per RECIST 1.1 criteria. Baseline pt characteristics, outcome to therapy and adverse effects as per CTCAE v5.0 were collected. Results: Thirteen pts with metastatic nccRCC histology who were treated with Ipi/Nivo were identified. The median age was 60 years (range, 32-81). Non clear cell histologies included adenocarcinoma of renal origin not otherwise specified (2), unclassified (3), papillary (3), chromophobe (3), translocation (1) and medullary histology (1). Nine pts had ECOG PS 0; four pts had ECOG PS 1. Eleven patients were male and two female. IMDC risk group at time of initiation of Ipi/Nivo was favorable (2 pt), intermediate (10 pts) and poor (1 pt). Nine pts received Ipi/ Nivo as first line treatment, three pts received Ipi/Nivo after prior TKI and one pt received Ipi/ Nivo as third line treatment after prior chemotherapy and nivolumab monotherapy. In total, eight pts have thus far undergone restaging scans with three pts demonstrating partial response (PR), one pt demonstrating stable disease (SD) and four pts demonstrating progressive disease (PD). Two pts experienced grade 2 diarrhea, one after 4 cycles and another after 3 cycles of Ipi/Nivo and required prednisone. One pt demonstrated grade 3 hepatotoxicity after 2 cycles of Ipi/Nivo and required prednisone and Mycophenolate Mofetil while another pt demonstrated grade 1 hepatotoxicity after 3 cycles of Ipi/ Nivo requiring prednisone. One pt experienced grade 2 pancreatitis requiring steroids after one dose of Ipi/Nivo. One pt experienced grade 2 fatigue after 1 cycle of Ipi/Nivo requiring prednisone. Conclusions: Ipi/Nivo is feasible and safe in patients with metastatic nccRCC with preliminary evidence of anti-tumor activity. Updated clinical data will be presented.