CXCR2 inhibition <i>in vivo</i> stabilizes progression of sorafenib-resistant tumors.

<p>SKOV-3 xenografts were treated with a daily dose of 30 mg/kg sorafenib until tumors developed phenotypic resistance to the treatment (~46 days). Mice with resistant tumors were then randomized into groups to receive one of the following: 30 mg/kg sorafenib alone (<i>n</i> = 6), 10 mg/kg SB225002 alone (<i>n</i> = 6), or sorafenib plus SB225002 (<i>n</i> = 6). The arrow indicates the start of treatment on day 46. Tumor volume was measured at the indicated times and is presented as mean ± S.D. The sorafenib and SB225002 combination led to 42% reduction in tumor growth compared with sorafenib alone (<i>P</i> < 0.05).