FOLFIRI and Panitumumab in Treating Patients With RAS and BRAF Wild-Type Metastatic Colorectal Cancer

PRIMARY OBJECTIVES: I. Estimate the response rate (RR) and progression-free survival (PFS) with FOLFIRI + panitumumab in patients with acquired resistance to panitumumab (or cetuximab) + irinotecan (irinotecan hydrochloride)-based therapy after a documented clinical response or prolonged PFS and following progression on a subsequent non-anti-EGFR containing regimen in extended RAS wild-type and BRAF wild-type patients. SECONDARY OBJECTIVES: I. Estimate the overall survival (OS) in the re-challenge populations. II. Describe the safety of re-challenge in this population. III. Investigate the impact of PFS, RR on prior anti-EGFR + irinotecan-based exposure on the response and PFS on the current study. TERTIARY OBJECTIVES: I. Collect serial plasma samples to investigate the incidence of RAS and BRAF mutation in circulating free deoxyribonucleic acid (DNA) at baseline, every 2 months, and at the time to progression (and following progression when feasible). II. Collect serial plasma samples for future biomarker exploration, including the potential investigation of micro-ribonucleic acid (RNA). OUTLINE: Patients receive panitumumab intravenously (IV) over 30-90 minutes, irinotecan hydrochloride IV over 90 minutes, leucovorin calcium orally (PO), and fluorouracil IV over 46 hours on day 1. Courses repeat every 2 weeks in the absence of disease progression or unacceptable toxicity. After completion of study treatment, patients are followed up at 30 days and then every 3 months thereafter.