Regorafenib, With Cetuximab or Panitumumab, for the Treatment of Unresectable, Locally Advanced, or Metastatic Colorectal Cancer

PRIMARY OBJECTIVE: I. To compare the overall survival between evaluable patients who were randomized to receive regorafenib followed by anti-EGFR monoclonal antibody therapy compared to those that receive anti-EGFR monoclonal antibody followed by regorafenib. SECONDARY OBJECTIVES: I. To compare the first progression free survival (PFS1) of patients between evaluable patients who were randomized to receive regorafenib followed by anti-EGFR monoclonal antibody therapy compared to those that receive anti-EGFR monoclonal antibody followed by regorafenib II. To compare the second progression free survival (PFS2) of patients between evaluable patients who were randomized to receive regorafenib followed by anti-EGFR monoclonal antibody therapy compared to those that receive anti-EGFR monoclonal antibody followed by regorafenib. III. To compare the sequential treatment progression free survival (stPFS) of patients between evaluable patients who were randomized to receive regorafenib followed by anti-EGFR monoclonal antibody therapy compared to those that receive anti-EGFR monoclonal antibody followed by regorafenib. IV. To assess the frequency and severity of adverse events between evaluable patients who were randomized to receive regorafenib followed by anti-EGFR monoclonal antibody therapy compared to those that receive anti-EGFR monoclonal antibody followed by regorafenib. V. To compare the objective response rate (ORR), while on initial treatment, between evaluable patients who were randomized to receive regorafenib followed by anti-EGFR monoclonal antibody therapy compared to those that receive anti-EGFR monoclonal antibody followed by regorafenib VI. To compare the objective response rate (ORR), while on sequential treatment, between evaluable patients who were randomized to receive regorafenib followed by anti-EGFR monoclonal antibody therapy compared to those that receive anti-EGFR monoclonal antibody prior to regorafenib. CORRELATIVE RESEARCH OBJECTIVES: I. To assess plasma pharmacodynamics biomarkers of response and resistance to therapy. II. To explore any correlation between tissue and blood based biomarkers and clinical outcomes. OUTLINE: Patients are randomized to 1 of 2 arms. ARM A: Patients receive regorafenib orally (PO) once daily (QD) on days 1-21. Cycles repeat every 28 days in the absence of disease progression or unacceptable toxicity. Per the treating physician's discretion, patients who experience disease progression may initiate a treatment regimen consisting of cetuximab or panitumumab intravenously (IV) over 30-90 minutes on days 1 and 15. Patients may also receive irinotecan IV on days 1 and 15 as determined by the study doctor. Cycles repeat every 28 days until disease progression or unacceptable toxicity. ARM B: Patients receive cetuximab or panitumumab IV over 30-90 minutes on days 1 and 15. Patients may also receive irinotecan IV on days 1 and 15 as determined by the study doctor. Cycles repeat every 28 days in the absence of disease progression or unacceptable toxicity. Per the treating physician's discretion, patients who experience disease progression may initiate a treatment regimen consisting of regorafenib PO QD on days 1-21. Cycles repeat every 28 days until disease progression or unacceptable toxicity. After completion of study treatment, patients are followed up at 30 days, and then every 3 months for up to 3 years after randomization.