TiNivo: safety and efficacy of tivozanib-nivolumab combination therapy in patients with metastatic renal cell carcinoma

Background: Treatment with tivozanib, a highly selective and potent vascular endothelial growth factor receptor tyrosine kinase inhibitor, has demonstrated single-agent efficacy in advanced renal cell carcinoma (RCC) along with minimal off-target toxicities and a favorable adverse event (AE) profile. We report final results from TiNivo, a phase Ib/II study of tivozanib combined with nivolumab. Patients and methods: In phase lb, patients with metastatic RCC received tivozanib 1.0 mg once daily (QD) for 21 days followed by 7 days off treatment (n = 3) or tivozanib 1.5 mg QD (n = 3) plus nivolumab 240 mg every 2 weeks. The maximum tolerated dose was determined to be tivozanib 1.5 mg, and 22 additional patients were enrolled at the maximum tolerated dose for phase II. Primary end points included safety and tolerability, with secondary end points of objective response rate, disease control rate, and progression-free survival. Results: In total, 25 patients were treated with tivozanib 1.5 mg QD [12 (48%) treatment-naive; 13 (52%) previously treated]. Treatment-related grade 3/4 AEs were reported in 20 patients (80%); 4 patients (17%) experienced AEs that led to dose reduction, and 8 (32%) discontinued due to AEs. The objective response rate was 56% (including one complete response) and disease control rate was 96%, with a median time to best response of 7.9 weeks. Twenty patients (80%) had tumor shrinkage. With a median follow-up of 19.0 months (range, 12.6-22.8), median progression-free survival was 18.9 months (95% confidence interval 16.4-not reached) in all patients and was similar in treatment-naive and previously treated patients. Conclusions: Tivozanib plus nivolumab combination therapy showed a generally tolerable AE profile and promising antitumor efficacy. These results support further development of tivozanib combined with nivolumab as a treatment option in patients with treatment-naive or previously treated metastatic RCC.