A Study of Amivantamab Monotherapy and in Addition to Standard-of-Care Chemotherapy in Participants With Advanced or Metastatic Colorectal Cancer

The purpose of this study is to assess the anti-tumor activity of amivantamab as a monotherapy (Cohorts A, B, and C), to characterize the safety of amivantamab when added to standard-of care (SoC) chemotherapy in participants with metastatic colorectal cancer (mCRC) (Ph2 cohorts), and to assess the recommended phase 2 combination dose (RP2CD) of amivantamab when added to SoC chemotherapy (Ph1b cohorts).

Colorectal cancer (CRC) is a major global health concern and the third most common cancer worldwide. Amivantamab (also known as RYBREVANT or JNJ-61186372) is a fully human immunoglobulin (Ig) G1-based bispecific antibody (Ab) directed against the epidermal growth factor (EGF) and mesenchymal epithelial transition (MET) receptors, with evidence of preclinical activity against non-small cell lung cancer (NSCLC) tumors with activating EGF receptor (EGFR) mutations, the T790M and C797S second-site resistance EGFR mutations, overexpressed wild-type EGFR, as well as with activation of the MET pathway. Amivantamab has demonstrated activity in both EGFR- and MET-driven NSCLC, with preclinical evidence demonstrating its ability to recruit immune effector cells. While two anti-EGFR antibodies are incorporated as part of the SoC for CRC patients, MET is highly expressed or amplified in subsets of CRC and additionally plays a role in mediating resistance to anti-EGFR treatments. The study consists of up to 28 days screening period, treatment period will begin on Cycle 1 Day 1 (C1D1) (for Cohorts A, B, and C) or C1D -2 (for Ph1b-D, Ph1b-E, Cohorts D and E) with the administration of the study treatment and continue as 28-day cycles until the end of treatment visit, up to 30 days after discontinuation of study treatment. The safety of amivantamab as a monotherapy or in addition to SoC chemotherapy will be assessed by physical examinations, Eastern Cooperative Oncology Group (ECOG) criteria for performance status (PS), laboratory tests, vital signs, monitoring of adverse events, and concomitant medication usage. The total duration of this study will be up to 4 years 3 months.

Eligibility Criteria:
Inclusion Criteria:

* Participant must have been previously diagnosed with histologically or cytologically confirmed unresectable or metastatic adenocarcinoma of the colon or rectum
* For Phase 1 dose confirmation cohorts (Cohorts Ph1b-D and Ph1b-E): Participant must have evaluable disease. For Phase 2 dose expansion cohorts (Cohorts D and E): Participant must have measurable disease according to Response Criteria in Solid Tumors (RECIST) Version 1.1. If only one measurable lesion exists, it may be used for the screening biopsy as long as baseline tumor assessment scans are performed greater than or equal to (\>=) 7 days after the biopsy
* Participant must have Eastern Cooperative Oncology Group (ECOG) performance status (PS) 0 or 1
* Participant must have a tumor lesion amenable for biopsy and agree to mandatory protocol-defined screening biopsy
* A female participant of childbearing potential must have a negative serum pregnancy test at screening and within 72 hours of the first dose of study treatment and must agree to further serum or urine pregnancy tests during the study. Note: Participant must not be pregnant, breastfeeding, or planning to become pregnant while enrolled in this study

Exclusion Criteria:

* Participant with identified mutation in Kirsten rat sarcoma viral oncogene (KRAS), neuroblastoma RAS viral oncogene homolog (NRAS), v-raf murine sarcoma viral oncogene homolog B (BRAF), or epidermal growth factor receptor (EGFR) ectodomain, or ERBB2/HER2 amplification by central circulating tumor deoxyribonucleic acid (ctDNA) testing at screening
* Participant with symptomatic or untreated brain metastasis
* History or known presence of leptomeningeal disease
* Any condition for which, in the opinion of the investigator, participation would not be in the best interest of the participant (for example, compromise the well-being) or that could prevent, limit, or confound the protocol-specified assessments