OBJECTIVETo study the inhibitory effect and toxicity of axitinib combined with 5-FU in nude mice bearing transplanted tumor of colon cancer LoVo cells.

METHODSNude mouse models bearing LoVo colon cancer xenograft were randomized into vehicle control group, untreated control group, axitinib-treated group, 5-FU-treated group and combined treatment group for corresponding treatments. The tumor dimensions, body weight and tumor weight were recorded, and the efficacy and toxicity were evaluated in terms of complete remission (CR), partial remission (PR), tumor growth delay (TGD), mortality rate and net body weight loss.

RESULTSThe combined treatment showed a significantly stronger efficacy than axitinib or 5-FU used alone. TGD of the combined treatment group was 16.73 days, longer than that of axitinib (8.53 days) and 5-FU (9.72 days) used alone. No mouse died during the treatments in the untreated control group, and 1 died in each of the other 4 groups. The mortality rate and weight loss were both less than 20%. One mouse had PR in axitinib-treated group and another in the combination treatment group. Axitinib, alone and in combination with 5-FU, reduced ABCG2 expression in the tumor tissue, and 5-FU has no such effect.

CONCLUSIONCombination of axitinib and 5-FU produces better antitumor effect than either drug used alone and is well tolerated in nude mice bearing colon cancer xenograft.