A phase II study of apatinib combined with S-1 in previously treated refractory metastatic colorectal cancer.

Abstract

e15016 Background: Although regorafenib and fruquintinib have been recommended as the third-line treatment for patients with refractory metastatic colorectal cancer (mCRC), the median survival time of mCRC is still only for 4-8 months and the low response rate and unpleasant side effects limit their use in Chinese patients. Apatinib, an oral VEGFR-2 inhibitor, has been approved as a third line treatment in metastatic gastric cancer. In addition, apatinib has demonstrated good safety, tolerability, and efficacy in the treatment of advanced solid tumors. The aim of this study was to assess the efficacy and safety of apatinib combined with S-1 in the treatment of refractory mCRC. Methods: In this prospective, open-label, single-arm, multicenter, phase II study, patients after failure of second-line chemotherapy were enrolled and took apatinib (250mg, daily) combined with S-1 (standard dose). The primary endpoint was progression free survival (PFS) and the second endpoint was response rate and overall survival time. Results: From December 2017, 22 patients (14 male) with a median age of 56y (range: 34-71 y) were enrolled and eligible for evaluation of the PFS, response rate and safety. The median PFS was 105d (95% CI: 79.01-130.98). two patients (9%) achieved partial response, 15 (68.18%) achieved stable disease, and 5 (22.72%) were progressive disease. The objective response rate and the disease control rate were 9% and 77.27%, respectively. Median overall survival was not reached. The common adverse effects were abnormal liver function (7/22; 31.81%), leukopenia (5/22; 22.72%) and thrombocytopenia (4/22; 18.18%). The incidence for grade 3-4 side effect was very low. One patient experienced grade 3 proteinuria and there were no toxic deaths. Conclusions: This preliminary result indicated that apatinib combined with S-1 may extend the PFS in mCRC, with well-tolerated toxicities, making it a promising therapeutic target for mCRC treatment. Clinical trial information: NCT03397199 .