Maintenance treatment with capecitabine plus cetuximab after first-line standard fluorouracil-based chemotherapy plus cetuximab for patients with RAS wild-type advanced colorectal cancer.

806 Background: The optimum duration of first-line treatment with chemotherapy in combination with cetuximab (CET) in patients with RAS wild-type (wt) advanced colorectal cancer (ACRC) is unknown. The current study was designed to evaluate the efficacy and safety of maintenance treatment (MT) with capecitabine (CAP) plus CET in ACRC. Methods: The trial was conducted at Department of Oncology, Tongji Hospital, Huazhong University of Science and Technology, China. We included patients with previously untreated RAS wt ACRC, with stable disease or better after induction treatment with 4-6 months of standard fluorouracil-based chemotherapy plus CET, WHO performance status of 0 or 1. The selected patients were assigned to MT-CAP (1250mg/m 2 orally twice daily on day 1-14 every 3 weeks), and CET (400 mg/m 2 on day 1 of the first week, then 250 mg/m 2 on day 1 every week). We assessed disease status every 6 weeks. The primary endpoint of the study was disease progression or unacceptable toxicity, defined as progression-free survival (PFS). All endpoints were calculated from the time of inclusion. Analyses were done by intention to treat. Results: From Jan. 1, 2014 to May 1, 2016, we assigned 13 patients to MT-CAP plus CET. Median follow-up time was 22 months. Median PFS was 16.7 months, and the PFS of MT was 12.1 months. MT was well tolerated, and none of the 13 patients discontinued treatment due to toxic effects. The general quality of life did not deteriorate during MT. Conclusions: MT-CAP plus CET after 4-6 months of standard chemotherapy and CET in ACRC patients was effective and did not compromise life quality. Based on these results, we launched a single arm, open-label, multi-center, Phase 2 clinical trial to investigate the efficacy and safety of MT-CAP plus CET after first-line standard fluorouracil-based chemotherapy plus CET for patients with RAS wt ACRC. The trial was registered with ClinicalTrials.gov, number NCT02717923, and approved by the Institutional Review Board of Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology. Clinical trial information: NCT02717923.