History of severe hypersensitivity reaction to any monoclonal antibody History of severe hypersensitivity reaction to any monoclonal antibody History of severe hypersensitivity reaction to monoclonal antibodies. No history of severe hypersensitivity to a monoclonal antibody History of allergy to study drug component or history of severe hypersensitivity reaction to any monoclonal antibody. History of severe hypersensitivity reaction to any monoclonal antibody Prior severe hypersensitivity reaction to another monoclonal antibody (mAb) Has had a severe hypersensitivity reaction to treatment with another monoclonal antibody. Has had a severe hypersensitivity reaction to treatment with another mAb Previous severe hypersensitivity reaction to treatment with another monoclonal antibody (mAb) Previous severe hypersensitivity reaction to treatment with another monoclonal antibody. Has had a severe hypersensitivity reaction to treatment with a monoclonal antibody/components of the study treatment(s). Any history of a severe hypersensitivity reaction to any monoclonal antibody Has had a severe hypersensitivity reaction to treatment with a monoclonal antibody (mAb). History of severe hypersensitivity reaction to any monoclonal antibody Previously had a severe hypersensitivity reaction to treatment with another monoclonal antibody. Previous severe hypersensitivity reaction to another monoclonal antibody, such as colitis or pneumonitis requiring treatment with steroids, or has a history of interstitial lung disease. Patients with a history severe (>= grade ) hypersensitivity reaction to a monoclonal antibody are ineligible EXCLUSION CRITERIA FOR STRATUM C: Patients with a history severe (>= grade ) hypersensitivity reaction to a monoclonal antibody are ineligible No prior severe infusion reaction to a monoclonal antibody History of severe hypersensitivity reaction to treatment with another monoclonal antibody History of severe hypersensitivity reaction to any monoclonal antibody. No prior severe infusion reaction to cetuximab or a monoclonal antibody History of severe hypersensitivity reaction to any monoclonal antibody History of severe hypersensitivity reaction to any monoclonal antibody. History of severe hypersensitivity reaction to another monoclonal antibody Any history of a sever hypersensitivity reaction to any monoclonal antibody Any history of a sever hypersensitivity reaction to any monoclonal antibody Severe or life-threatening anaphylaxis or hypersensitivity reaction when previously exposed to rituximab or other monoclonal antibody (mAb) therapy History of severe hypersensitivity reaction to any monoclonal antibody. History of severe hypersensitivity reaction to any monoclonal antibody including pembrolizumab Severe hypersensitivity reaction to treatment during prior administration of a monoclonal antibody (mAb) or history of allergy to any study drug component History of severe hypersensitivity reaction to any monoclonal antibody History of severe hypersensitivity reaction to any monoclonal antibody and/or to study drug components History of severe hypersensitivity reaction to any monoclonal antibody History of severe hypersensitivity reaction to any monoclonal antibody History of severe hypersensitivity reaction to any monoclonal antibody History of severe hypersensitivity reaction to any monoclonal antibody or study drug components History of severe hypersensitivity reaction to any monoclonal antibody History of severe hypersensitivity reaction to any monoclonal antibody Previous severe hypersensitivity reaction to another monoclonal antibody History of severe hypersensitivity reaction to any monoclonal antibody History of severe hypersensitivity reaction to any monoclonal antibody History of severe hypersensitivity reaction to any monoclonal antibody History of severe hypersensitivity reaction to any monoclonal antibody History of severe hypersensitivity reaction to other monoclonal antibodies Prior severe infusion reaction to a monoclonal antibody Known severe (grade or ) infusion-related allergy or hypersensitivity to any monoclonal antibody History of severe hypersensitivity reaction to any monoclonal antibody ADDITIONAL CRITERIA FOR STUDY CONTINUATION: History of severe hypersensitivity reaction to any monoclonal antibody Severe hypersensitivity reaction to treatment with another monoclonal antibody Patient previously had a severe hypersensitivity reaction to treatment with another monoclonal antibody (mAb) or interferon-alphab (IFN-ab) Severe or life-threatening anaphylaxis or hypersensitivity reaction when previously exposed to rituximab or other monoclonal antibody therapy History of severe hypersensitivity reaction to any monoclonal antibody Patient previously had a severe hypersensitivity reaction to treatment with another monoclonal antibody (mAb) Patients with a history of severe (grade >= ) hypersensitivity reaction to a monoclonal antibody are ineligible Patients who have had a prior severe infusion reaction to a monoclonal antibody are not eligible Any history of a severe hypersensitivity reaction to any monoclonal antibody History of severe hypersensitivity reaction to any monoclonal antibody No prior severe infusion reaction to a monoclonal antibody History of severe hypersensitivity reaction to any monoclonal antibody Prior severe infusion reaction to a monoclonal antibody Previously had a severe hypersensitivity reaction to treatment with another monoclonal antibody (mAb). Severe hypersensitivity reaction to treatment with another monoclonal antibody (mAb) History of severe hypersensitivity reaction to any monoclonal antibody History of severe hypersensitivity reaction to any monoclonal antibody Prior severe infusion reaction to a monoclonal antibody Severe hypersensitivity reaction to treatment with another monoclonal antibody Prior severe hypersensitivity reaction to another monoclonal antibody (mAb) Patients who previously had a severe reaction to treatment with a human antibody. Participant has previous severe hypersensitivity reaction to another monoclonal antibody (mAb). History of severe hypersensitivity reaction to any monoclonal antibody Patient previously had a severe hypersensitivity reaction to treatment with another monoclonal antibody (mAb) History of severe hypersensitivity reaction to any monoclonal antibody History of severe hypersensitivity reaction to any monoclonal antibody No prior severe infusion reaction to cetuximab or a monoclonal antibody History of severe hypersensitivity reaction to any monoclonal antibody Previous serious hypersensitivity reaction to monoclonal antibodies. (Determination of \serious\ hypersensitivity reaction is at the investigator's discretion.) History of severe hypersensitivity reaction to any monoclonal antibody Has a history of a severe hypersensitivity reaction to treatment with another monoclonal antibody Has had a severe hypersensitivity reaction to treatment with another monoclonal antibody History of severe reaction to prior monoclonal antibody therapy (defined as a Grade event and/or requiring permanent discontinuation) History of severe infusion reaction to any monoclonal antibody History of severe hypersensitivity reaction to any monoclonal antibody History of severe hypersensitivity reaction to any monoclonal antibody Prior severe infusion-related reaction to a monoclonal antibody Prior severe infusion reaction to a monoclonal antibody History of severe hypersensitivity reaction to any monoclonal antibody History of severe hypersensitivity reaction to any monoclonal antibody History of allergy to study drug component or history of severe hypersensitivity reaction to any monoclonal antibody History of severe hypersensitivity reaction to other monoclonal antibodies History of severe hypersensitivity reaction to any monoclonal antibody