Efficacy of regorafenib monotherapy in metastatic colorectal cancer patients refractory to standard chemotherapy

Abstract

Background: Only limited treatment options are available for patients with metastatic colorectal cancer that progresses after standard chemotherapy. Regorafenib is an oral multikinase inhibitor that has been recently shown to be effective in metastatic colorectal cancer after failure to standard therapy. Methods: Patients with metastatic colorectal cancer in Seoul National University Hospital who have failed to standard therapy were treated with regorafenib, 160mg p.o daily, for the first 3 weeks of each 4 week cycle. For practical reasons, failure to standard therapy was defined as failure to all of fluoropyrimidine, oxliplatin and irinotecan, but did not mandate failure to bevacizumab or cetuximab. The primary end point was progression-free survival. Results: Between December 1, 2013 and February 1, 2014, 40 patients initiated treatment with regorafenib. Median progression-free survival of all patients was 4.3 months. Disease control rate was 70%. Patients who have not previously received bevacizumab showed significantly longer progression-free survival compared to those who have already failed to bevacizumab (2 vs. 4 months, P=0.003). Treatment-related adverse events occurred in 32 (80%) patients, but most were grade 1 or 2 and were generally manageable. The most common adverse event was hand-foot syndrome, occurring in 24 (60%) patients. Conclusion: Regorafenib is an acceptible treatment option in patients with metastatic colorectal cancer refractory to standard chemotherapeutic agents, with a manageable toxicity profile. Further study of identifying a subset of patients who would benefit more from the drug is warranted.