CTLA4 and cancer: To date Fc enhancing technology for anti-cancer reagents has been limited to a panel of checkpoint blockade targeting bispecific mAb generated by Xencor using Xtend technology (Xmab23104: PD-1 x LAG3, XmAb22841: CTLA-4 x LAG3 and XmAb20717: PD-1 x CTLA-4) and no whole IgG molecules have progressed.