Early-Line Anti-EGFR Therapy to Facilitate Retreatment for Select Patients With mCRC

Inclusion Criteria: * Written informed consent and HIPAA authorization for release of personal health information * As determined by the enrolling physician or protocol designee, ability of the participant to understand and comply with study procedures for the entire length of the study * Eastern Cooperative Oncology Group (ECOG) Performance Status of 0 to 2 * Have a diagnosis of histologically confirmed metastatic colorectal cancer with primary tumor located beyond the splenic flexure. Histologic confirmation of a colorectal primary tumor is acceptable if accompanied by radiographic evidence of metastatic disease. * For Cohort A: Participants must enroll for study treatment in the first or second-line metastatic setting. Participants may receive 1 month of standard chemotherapy in the metastatic setting and still be eligible to initiate protocol therapy in the first-line setting. Adjuvant or neoadjuvant therapy does not count as a line of therapy even if given in the setting of metastatic disease (oligometastatic), unless disease recurrence was noted within 6 months of completing the last dose of the adjuvant or neoadjuvant therapy. * For Cohort B: Participants must have had at least stable disease (per treating physician) on a prior EGFR inhibitor containing regimen and it must be at least 4 months since the prior anti-EGFR inhibitor treatment was completed. Participants previously enrolled in Cohort A can later enroll in Cohort B should the eligibility criteria be me…