Tivozanib versus sorafenib as initial targeted therapy for patients with advanced renal cell carcinoma: Results from a phase III randomized, open-label, multicenter trial.

4501 Background: Tivozanib, a potent, selective, long half-life tyrosine kinase inhibitor targeting all three VEGF receptors, showed activity and tolerability in a Phase II trial (JCO 2011;29[18S]:4550). Methods: Patients (pts) with clear cell advanced renal cell carcinoma (RCC), prior nephrectomy, RECIST-defined measurable disease, and Eastern Cooperative Oncology Group (ECOG) performance status 0 or 1 were randomized 1:1 to tivozanib (T) 1.5 mg once daily for 3 weeks (wks) followed by 1 wk rest, or sorafenib (S) 400 mg twice daily continuously in a 4-wk cycle. Pts were treatment naïve or received no more than 1 prior systemic therapy for metastatic disease; pts receiving prior VEGF- or mTOR-targeted therapy were excluded. The primary endpoint was progression-free survival (PFS) per blinded, independent radiological review. 500 pts were to be enrolled to observe 310 events, yielding 90% power to detect medians of 9.7 and 6.7 months (m) with 5% type I error (2-sided). Results: A total of 517 pts were randomized to T (n=260) or S (n=257). Demographics were well balanced between the 2 groups, except ECOG 0 (T: 45% vs S: 54%, p=0.035). Median PFS was 11.9 m for T vs 9.1 m for S (HR=0.797, 95% CI 0.639–0.993; p=0.042). In the treatment-naïve stratum (70% of pts enrolled in each arm), the median PFS was 12.7 m for T vs 9.1 m for S (HR 0.756, 95% CI 0.580–0.985; p=0.037). In all pts, objective response rate (ORR) for T was 33% vs 23% for S (p=0.014). The most common adverse event (AE; all grades/≥grade 3) for T was hypertension (T: 46%/26% vs S: 36%/18%) and for S was hand-foot syndrome (T: 13%/2% vs S: 54%/17%). Other important AEs included diarrhea (T: 22%/2% vs S: 32%/6%), fatigue (T: 18%/5% vs S: 16%/4%), and neutropenia (T: 10%/2% vs S: 9%/2%). Patient-reported outcome data are being analyzed. Overall survival data are not mature. Conclusions: Tivozanib demonstrated significant improvement in PFS and ORR compared with sorafenib as initial targeted treatment for advanced RCC. The safety profile of tivozanib is favorable, and includes a low incidence of fatigue, diarrhea, myelosuppression, and hand-foot syndrome.