Optimizing Treatment Sequence for Late-line Metastatic Colorectal Cancer Patients Using Trifluridine/Tipiracil and Regorafenib

Abstract Background Treatment sequencing for patients with refractory metastatic colorectal cancer (mCRC) has been highly debated. The thymidine-based nucleoside trifluridine/tipiracil (TAS-102) and the multikinase inhibitor regorafenib have demonstrated clinical benefits in randomized phase III trials compared with placebo. However, limited data are available on the most optimal therapy sequence involving TAS-102 and regorafenib. Patients and Methods In the present retrospective, observational, real-life study, clinical data on mCRC patients treated with TAS-102 or an alternative salvage treatment at the Medical University of Vienna and University Hospital Zurich were collected from January 2013 to December 2016. Results A total of 85 patients whose disease had progressed during fluoropyrimidine-based therapy (FBT) with or without an antibody were included. The disease control rate in patients treated with TAS-102 after FBT-based treatment was 24% compared with 35% in patients treated with regorafenib after FBT-based treatment (adjusted odds ratio, 1.75; 95% confidence interval, 0.41-7.47; P  = .449). The progression-free survival (PFS) and overall survival (OS) for patients treated with TAS-102 was 2.8 months (quartile, 2.0-4.8 months) and 15.9 months, respectively. When the data were analyzed according to the subgroups of patients with or without an FBT-free period, the TAS-102–treated patients with a previous FBT-free interval had a PFS of 3.1 months and OS of 17.7 months compared with a PFS of 2.2 months and OS of 8.1 months for patients who received TAS-102 immediately after FBT. Conclusion Our results have confirmed the efficacy of TAS-102 and regorafenib in the real-life setting. The treatment sequence analysis showed a tendency for longer PFS and OS for TAS-102–treated patients after an FBT-free interval. Prospective randomized data are needed to gain more information about the most beneficial therapy sequence in the salvage treatment of mCRC.