TAS-102 followed by regorafenib or the reverse sequence in advanced colorectal cancer

Background: TAS-102 and regorafenib were shown to have clinical activity in a large population of Japanese and Western patients with heavily pretreated advanced colorectal cancer. Median OS and PFS of TAS-102 were reported 7.1 and 2.0 months, and median OS and PFS of regorafenib were 6.4 and 1.9 months for refractory colorectal cancer. We usually treated TAS-102 and regorafenib for refractory colorectal cancer at late-line. However whether TAS-102 or regorafenib should be first is not clear. So we assessed efficacy and safety of TAS-102 and regorafenib for refractory metastatic colorectal cancer at retrospective. Methods: We selected patients with advanced colorectal cancer treated both TAS-102 and regorafenib between June 2014 and October 2017 in our institution. TAS-102 (with each dose consisting of 35 mg per square meter) was administered twice daily, 5 days a week, with 2 days of rest, for 2 weeks, followed by a 14-day rest period, thus completing one treatment cycle. Regorafenib was administered 160 mg once daily for the first 3 weeks of each 4-week cycle. Results: 21 patients were treated of TAS-102 followed by regorafenib (TR) and 11 patients were treated of regorafenib followed by TAS-102 (RT). The median age of TR and RT were 63 and 60 years. Performance status of 1 and 2 for TR were 17 and 4, RT were 7 and 4 patients. All patients had received prior chemotherapy containing a fluoropyrimidine, oxaliplatin, and irinotecan. Response rate of TR and RT were 4% and 0%, disease control rate of TR and RT were14% and 18%. Median PFS of TR and RT were 54 days (95%CI 18-136) and 50 days (95%CI 25-167). Median OS of TR and RT were 237 days (95%CI 70-645) and 242 days (95%CI 79-405). Treatment discontinuation due to adverse events was more frequent in regorafenib phase. Conclusions: There were no significant differences of effectiveness for TAS-102 followed by regorafenib or the reverse sequence in advanced colorectal cancer. Legal entity responsible for the study: Haruko Daga Department of Medical Oncology, Osaka City General Hospital, Osaka, Japan. Funding: Has not received any funding. Disclosure: All authors have declared no conflicts of interest.