Premedication to Reduce Amivantamab Associated Infusion Related Reactions

The purpose of the study is to separately assess the potential of dexamethasone, montelukast and methotrexate administration, prior to amivantamab infusion given through a needle in the vein, to decrease the incidence and/or severity of first-dose infusion related reactions.

Inclusion Criteria: * Participant must have advanced or metastatic non-small cell lung cancer (NSCLC) * Eastern Cooperative Oncology Group (ECOG) performance status grade of 0 or 1 * A female participant using oral contraceptives must use an additional barrier contraceptive method * A male participant must wear a condom when engaging in any activity that allows for passage of ejaculate to another person during the study and for 3 months after receiving the last dose of study treatment, oral lazertinib and intravenous (IV) Amivantamab * Each participant, or legally authorized representative, where allowed, must sign an informed consent form (ICF) indicating that the participant understands the purpose of, and procedures required for, the study and is willing to participate in the study * Progressed on or after prior treatment with osimertinib and platinum-based chemotherapy. Prior use of first-or-second generation epidermal growth factor receptor tyrosine kinase inhibitor (EGFR TKI) is allowed if administered prior to osimertinib * Previously identified EGFR-mutated non-small cell lung cancer (NSCLC) (EGFR Exon19 deletion or L858R) (identified locally in a Clinical Laboratory Improvement Amendments \[CLIA\]-certified laboratory \[or equivalent\]) Exclusion Criteria: * Participant has a medical history of interstitial lung disease (ILD), including drug-induced ILD or radiation pneumonitis * Prior treatment with anti PD-1 or anti PD-L1 antibody within 6 weeks of planned first dose of study treatment or immune-mediated rash from checkpoint inhibitors that has not resolved prior to enrollment * Participant has symptomatic brain metastases. A participant with asymptomatic or previously treated and stable brain metastases may participate in this study. Participants who have completed definitive therapy, are not on steroids, and have a stable clinical status for at least 2 weeks prior to study treatment are allowed. If brain metastases are diagnosed on Screening imaging, the participant may be enrolled, or rescreened for eligibility, after definitive treatment if above criteria are met * Any toxicities from prior anticancer therapy must have resolved to common terminology criteria for adverse events (CTCAE) version 5.0 Grade 1 or baseline level (except for alopecia \[any grade\], Grade less than or equal to \[\