4506 Background: Sunitinib (S) is established as a standard first-line therapy for patients (pts) with advanced RCC. However, treatment can be limited by the occurrence of drug-related adverse events (AEs). This Phase II study assessed the efficacy and safety of nintedanib (N) – a potent, triple angiokinase inhibitor of VEGFR-1–3, PDGFR-α/β, and FGFR-1–3, as well as RET and Flt3 – vs S in previously untreated pts with RCC. Methods: Ninety-nine eligible pts (96 of whom were treated) with advanced, unresectable/recurrent clear cell RCC, an ECOG performance status of 0–1, and no prior systemic therapy were randomized 2:1 to receive N 200 mg twice daily (n=64; given in 4-week cycles) or S 50 mg once daily (n=32; 4 weeks on, 2 weeks off schedule). Treatment continued until disease progression or unacceptable drug-related AEs. Primary endpoints were progression-free survival at 9 months (PFS-9) and, in N-treated pts only, QTc interval change (baseline to day 15). Secondary endpoints included PFS, objective response rate (ORR; RECIST 1.1), overall survival (OS), time to progression (TTP), time to treatment failure (TTF), and AEs. Results: Baseline characteristics were balanced between the arms. PFS-9 was not statistically significantly different between N- and S-treated pts (43 vs 45%; p=0.85). There were also no statistically significant differences between N and S with regard to PFS (median: 8.44 vs 8.38 mo; hazard ratio: 1.16; 95% CI: 0.71–1.89; p=0.56), confirmed ORR (18.8 vs 31.3%; p=0.19), OS (median: 20.37 vs 21.22 mo; p=0.63), TTP (median: 8.48 vs 8.54 mo; p=0.52), and TTF (median: 8.41 vs 8.36 mo; p=0.46). Grade ≥3 AEs occurred in 47% of N-treated pts and 56% of S-treated pts. Common AEs (all grades; N vs S) included diarrhea (61 vs 50%), nausea (38 vs 34%), fatigue (both 25%), and vomiting (16 vs 22%). Dermatologic AEs (8 vs 47%) were less frequent with N than S. There was no increase from baseline in QTc >60 ms on days 1 or 15 in N-treated pts, and there was no relationship between N exposure and QT interval change. Conclusions: N demonstrated similar efficacy to S and had a manageable safety profile, including a lower incidence of dermatologic AEs vs S. In addition, N was not associated with QT prolongation. Clinical trial information: NCT01024920.