A Study of Amivantamab and mFOLFOX6 or FOLFIRI Versus Cetuximab and mFOLFOX6 or FOLFIRI as First-line Treatment in Participants With KRAS/NRAS and BRAF Wild-type Unresectable or Metastatic Left-sided Colorectal Cancer

The purpose of this study is to compare how long the participants are disease-free (progression-free survival) when treated with amivantamab and chemotherapy with 5-fluorouracil, leucovorin calcium (folinic acid) or levoleucovorin, oxaliplatin (mFOLFOX6) or 5-fluorouracil, leucovorin calcium (folinic acid) or levoleucovorin, and irinotecan hydrochloride (FOLFIRI) versus cetuximab and mFOLFOX6 or FOLFIRI in adult participants with Kirsten rat sarcoma viral oncogene homolog (KRAS)/ Neuroblastoma RAS viral oncogene homolog (NRAS) and v-Raf murine sarcoma viral oncogene homolog B1 (BRAF) wild type (WT) unresectable or metastatic left-sided colorectal cancer.

• : * Have histologically or cytologically confirmed adenocarcinoma of the left-sided colorectal cancer. Participants must have unresectable or metastatic disease * Determined to have Kirsten rat sarcoma viral oncogene (KRAS), neuroblastoma RAS viral oncogene homolog (NRAS), and v-raf murine sarcoma viral oncogene homolog B (BRAF) wild-type (WT) tumor by local and/or central testing (if available) * Must agree to the submission of fresh tumor tissue * Have measurable disease according to RECIST v1.1 * Has not received any prior systemic therapy for unresectable or metastatic colorectal cancer (CRC). Prior adjuvant/neoadjuvant therapy in the non-metastatic disease is permitted. However, the last course of adjuvant or neoadjuvant chemotherapy must have concluded greater than (>) 12 months prior to CRC recurrence/metastases * Have an eastern cooperative oncology group (ECOG) performance status (PS) of 0 or 1

Use the source registry for the full inclusion and exclusion criteria before discussing referral or enrolment.