INMUNOSUN-SOGUG trial: A prospective phase II study to assess the efficacy and safety of sunitinib as second-line (2L) treatment in patients (pts) with metastatic renal cell cancer (RCC) who received immunotherapy-based combination upfront

5060 Background: Immunotherapy (IO)-based combinations have replaced tyrosine kinase inhibitors (TKI) as standard upfront treatment of metastatic RCC pts. Selection of 2L treatment after progression to novel combinations in 1st-line (1L) is mostly based on retrospective series or subgroups analysis of randomized trials. We aim to evaluate the activity and safety of sunitinib in advanced RCC after progression on an IO-based 1L approach. Methods: This is a prospective, non-randomized, open-label and multicenter phase II study. Pts with ECOG 0-2 and locally advanced or metastatic RCC after treatment in 1L with a prior PD-1 and/or PD-L1 and/or CTLA-4 inhibitor were included. Sunitinib was administered at 50 mg/day on a 4/2 schedule until disease progression. Primary endpoint was overall response rate (ORR) by RECIST v 1.1 criteria. Results: Twenty pts were enrolled in the study. Median age was 66 yo, 70% had intermediate prognosis by Heng's scale, and 88% ECOG 1. 45% of pts received atezolizumab, 30% pembrolizumab, 20% nivolumab and 15% ipilimumab-based regimens as 1L. ORR to 1L treatment was 45%. Median time from end of 1L to sunitinib onset date was 1.1 months (0.3-22.1). Two (10%) pts had partial response with sunitinib and 11 (55%) stable disease for a total disease control rate of 65%. With a median follow-up of 8.8 months, median PFS was 6.8 months (0.0-13.9) and median OS 13.6 months (10.5-16.6). Median duration of treatment was 4 months (0.9-16-2). Most common treatment-related adverse events, all grades, were asthenia (55%), dysgeusia (35%), diarrhea (30%), hypertension (30%), mucosal inflammation (25%), palmar-plantar erythrodysesthesia (25%), anemia (20%), neutropenia (20%) and nausea (15%); grade 3 were asthenia (15%), hypertension (10%) and neutropenia (10%). Conclusions: To our knowledge, the INMUNOSUN trial is the first study to evaluate prospectively the activity of a single agent TKI in a pure 2L setting of metastatic RCC pts treated with an IO-based approach upfront. ORR and PFS with sunitinib seem lower than expected when used as a 1L. Consistency in toxicity profile was observed. Clinical trial information: NCT03066427 .