Tivozanib: is total VEGFR inhibition the way to success in terms of tolerability and efficacy in advanced kidney cancer?

The fami ly of t yrosine k inase inhibitors is st i l l growing. After sunitinib, sorafenib and more recently pazopanib, and axitinib, we probably now should count on tivozanib (1). This pan-VEGFR inhibitor (VEGFR1,- R2,-R3) is more selective and potent in vitro than previous known TK inhibitors. Tivozanib was tested in a phase II trial reported by Nosov et al. (1) Tivozanib was administered at a daily dose of 1.5 mg, for 3 weeks followed by a break of 1 week. Of the 272 patients treated during the first period of 16 weeks, 78, who presented tumour shrinkage of at least 25%, were maintained on tivozanib. All of the 118 patients who presented less than 25% change in the tumour, were randomized between placebo and tivozanib, during the next 12 weeks.