TEK and neoplasm: With the goal to enhance the efficacy of anti-VEGFR2–anti-CD3 bsAb and, at the same time, improve the selectivity of tumor endothelial cell targeting while reducing off-target effects against VEGFR2-expressing normal EC, we employed a costimulatory bsAb targeting the angiopoietin (ANG) receptor TIE2 that is overexpressed in tumor neovasculature and is involved in vascular remodeling [21,22].