Table 1. Overview of (potential) advantages of bispecific heterodimeric antibodies over classical IgG antibodies and their combination.

Area	(Potential) advantage of bispecific (heterodimeric) antibodies
Structure	• Natural IgG architecture and geometry      • Lower risk for immune complexes compared with multivalent bispecific antibodies due to monovalency for each target
Targeting	• Transport e.g., delivery over the blood-brain barrier      • Effector cell recruitment to enhance killing      • Selective targeting of a selected cell population characterized by two targets to improve safety and/or efficacy
Efficacy	• Blocking two pathways in parallel to impair resistance formation (receptor tyrosine kinases, angiogenic ligands)      • Potential for synergistic effects compared with combination therapy
Development	• No need for separate single agent trials followed by combination trials      • No development of a co-formulation      • No extended infusion times (convenience)      • Advantageous pharmacoeconomics and lower cost of goods compared with two single antibodies      • Potential for combination with additional agents