TIVO-3: A phase III, randomized, controlled, multicenter, open-label study to compare tivozanib to sorafenib in subjects with refractory advanced renal cell carcinoma (RCC).

Abstract

541 Background: Tivozanib (T) is a biochemically potent and highly selective VEGF tyrosine kinase receptor inhibitor in clinical development in RCC. The TIVO-1 trial in treatment naïve or prior cytokine-treated subjects with metastatic (m) RCC showed a median progression free survival (mPFS) of 11.9 months (mos) for T compared to 9.1 mos for sorafenib (S) (p = 0.042, HR = 0.797). However, overall survival (OS) favored sorafenib, likely due to imbalanced crossover to active treatments. TIVO-3 was conducted to confirm the PFS results from TIVO-1. Methods: Subjects with mRCC who failed 2 or 3 prior systemic regimens, one of which included a VEGFR TKI other than S or T, were stratified by IMDC risk category and type of prior therapy (two TKIs; TKI plus checkpoint; TKI + other) then randomized in a 1:1 ratio to T or S. The primary objective was to compare PFS by blinded independent radiological review. 350 subjects were enrolled to yield 244 events with ~88% power to detect a difference of 6 mos vs. 4 mos with a two-sided p-value of 0.05 by the log-rank test. Secondary endpoints were OS, safety, objective response rate (ORR), and duration of response. Results: The two arms were well balanced for demographics and prior cancer history.60% of subjects had 2 prior lines of therapy and 40% had 3 prior lines. 28% had prior treatment with a checkpoint inhibitor. T demonstrated a statistically significant improvement in mPFS compared to S, 5.6 (95% CI 7.3-5.3) v. 3.9 mos (95% CI 5.6-3.7; HR 0.73; p=0.02). PFS rate at 2 years was 18% for T compared to 5% for S. ORR was 18% for T compared to 8% for S. 44% of T treated subjects experienced a grade 3 treatment-related adverse event compared to 55% for S. Subjects on T were less likely to require a dose reduction (24% v. 38%), interruption (48% v. 63%), or discontinuation (21% v. 29%) due to an adverse event than subjects on S. Conclusions: T is superior to S as measured by PFS; 2-year PFS, and ORR in this pre-treated population and is better tolerated than S. OS data will be updated prior to presentation. Clinical trial information: NCT02627963.