Primary refractory disease (i.e. never responded (? MR) to any prior therapy) Never responded Primary refractory disease (i.e. never responded with ? MR to any prior therapy) Primary refractory patients (never responded to any therapy) are eligible Participants who were refractory to all lines of previous treatment(s) (ie, participants who had never responded to any therapies received). Patients who have had prior anti-epidermal growth factor receptor (EGFR) antibody therapy and who have not responded to this treatment will be excluded; however, patients who have responded to prior anti-EGFR therapy are eligible