Sym004 Versus Futuximab or Modotuximab in Patients With mCRC

Following consent and prior to randomization, genomic analysis will be conducted on blood samples obtained from each potential patient. Triple-negative (TN) results as defined in trial eligibility criteria will be required for initial eligibility. Patients with TNmCRC will continue in the screening process. Once deemed fully eligible, patients will be randomized to Arm A, Arm B, or Arm C. Dosing cycles of 28 days will continue until documented disease progression (PD) or another criterion for discontinuation is met. Antitumor activity will be assessed at the end of every 2 cycles (every 8 weeks \[Q8W\]). At the End of Cycle 2 (EOC2) tumor assessment: * Patients assigned to Arm A (Sym004) with a documented objective response (OR) or stable disease (SD) will continue to receive Sym004; patients at the EOC2 with documented PD will be discontinued from study * Patients assigned to Arm B (futuximab) or Arm C (modotuximab) with a documented OR or SD will be crossed-over to receive Sym004; patients with documented PD at the EOC2 (or prior to the EOC2) will be offered the opportunity to crossover to receive Sym004 or will be discontinued from study To be considered evaluable for antitumor activity assessment, patients must have completed 2 cycles of dosing inclusive of EOC2 disease imaging studies and must have received any amount of their assigned investigational medicinal product (IMP) during that period, or have PD documented by imaging studies prior to the EOC2. Non-evaluable patients and patients discontinuing from study prior to the EOC2 for reasons other than documented PD will not be replaced. Note: In December 2018, the decision was made to terminate the trial and enrollment was prematurely discontinued. The primary, secondary, and exploratory objectives are no longer applicable. Only clinical safety-related evaluations will be conducted.