Table 1. In Vitro Cytotoxicity and Bystander Killing Activity of ADCs mAb_E-21a–mAb_E-21d.

	cell lines IC50 (M)		bystander IC50 (M)c
ADC	NLa Ag–	Mbb Ag+	Ag–:Ag+
mAbE-21a	1 × 10–7	4 × 10–10	4 × 10–9
mAbE-21b	5 × 10–7	7 × 10–10	5 × 10–10
mAbE-21c	6 × 10–7	1 × 10–9	6 × 10–10
mAbE-21d	1 × 10–7	7 × 10–10	2 × 10–9

^aNamalwa/luc cells (NL).

^bMDA-MB-468 cells (Mb).

^cBystander killing indicates the IC₅₀ for killing Ag– cells in the mixture of Ag– and Ag+ cells (Ag–:Ag+). The Ag– and Ag+ cells are NL and M,b respectively.