PRIMARY OBJECTIVES:~I. To evaluate the efficacy of trastuzumab and pertuzumab (TP) (Arm 1) in HER-2 amplified metastatic colorectal cancer (mCRC) by comparing progression-free survival (PFS) on TP compared to control arm (Arm 2) of cetuximab and irinotecan hydrochloride (irinotecan) (CETIRI).~SECONDARY OBJECTIVES:~I. To evaluate the overall response rate (ORR), including confirmed complete and partial response per Response Evaluation Criteria in Solid Tumors (RECIST) 1.1, in treatment Arms 1 and 2.~II. To evaluate the overall survival (OS) in treatment Arms 1 and 2. III. To evaluate the safety and toxicity of TP compared to CETIRI.~TERTIARY OBJECTIVES:~I. To estimate the rates of PFS, OS, and ORR in patients who crossover to TP (Arm 3) after disease progression on CETIRI.~II. To bank images for future retrospective analysis. III. To evaluate if HER-2/centromeric probe (CEP17) signal ratio and HER-2 gene copy number (GCN) are predictive of clinical efficacy for patients receiving TP versus CETIRI.~IV. To bank tissue and blood samples for other future correlative studies from patients enrolled on the study.~OUTLINE: Patients with HER2 gene amplification are randomized to 1 of 2 arms.~ARM I: Patients receive pertuzumab intravenously (IV) over 30-60 minutes and trastuzumab IV over 30-120 minutes on day 1. Courses repeat every 21 days in the absence of disease progression or unacceptable toxicity.~ARM II: Patients receive cetuximab IV over 60-120 minutes and irinotecan hydrochloride IV over 90 minutes on day 1. Courses repeat every 14 days in the absence of disease progression or unacceptable toxicity. Patients with documented disease progression may optionally crossover to Arm I.~After completion of study treatment, patients are followed up for 3 years.
This randomized phase II trial studies how well trastuzumab and pertuzumab work compared to cetuximab and irinotecan hydrochloride in treating patients with HER2/neu amplified colorectal cancer that has spread from where it started to other places in the body and cannot be removed by surgery. Monoclonal antibodies, such as trastuzumab and pertuzumab, may interfere with the ability of tumor cells to grow and spread. Drugs used in chemotherapy, such as cetuximab and irinotecan hydrochloride, work in different ways to stop the growth of tumor cells, either by killing the cells, by stopping them from dividing, or by stopping them from spreading. Giving trastuzumab and pertuzumab may work better compared to cetuximab and irinotecan hydrochloride in treating patients with colorectal cancer.