Table 3.

Summary of preclinical results for antibody–drug conjugates developed for myeloma.

	Company	Target	Linker	Payload	MM cell EC50*	Pros	Cons	Trial status
Indatuximab Ravtansine	Biotest	CD138	Cleavable	DM4	1 nM	Good target cell specificity	Internalization efficiency unknown	Phase I/Iia (open)
Lorvotuzumab mertansine	ImmunoGen	CD56	Cleavable	DM1	10–50 nM	Upregulated expression on MM cells	Expression on other cell types	Development discontinued
Milatuzumab–DOX	Immunomedics	CD74	Acid labile hydrazone	Doxorubicin	900 nM	Rapid internalization and recycling	Lower potency, labile linker	Phase I (not open)
anti-FcrL5 ADC	Genetech	FcrL5	Cleavable & non- cleavable	DM4, MMAF and MMAE	0.33 nM	High target cell specificity	Low expression level?	Not yet registered
GSK2857916	GlaxoSmith Kline	BCMA	Non-cleavable	MMAF	0.08–6.6 nM	High target cell specificity	Variable expression level	Phase I (not open)

^*Cross-comparison of agent EC50s is limited due to varying assay conditions and cell lines used in the study.