Figure 3.

Mechanisms of belantamab toxicity in human telomerase-immortalized corneal epithelial cells. Dose-titration curves for human telomerase-immortalized corneal epithelial (hTcEpi) cells treated with increasing concentrations of belantamab (A) and MMAF (B) for 72 hours as quantified by Alamarblue assay. (C) Measurements of dissociation constants (KD) for the interaction between belantamab and soluble B-cell maturation antigen (sBCMA) by surface plasmon resonance spectroscopy (SPR). Experimental curves are given in black, fitted curves in other colors. (D) Bar chart illustrating belantamab-specific cell killing in hTcEpi in the presence versus absence of the pinocytosis inhibitor EIPA (20 µM). hTcEpi cells were treated for 2 hours with EIPA followed by 3 days treatment with belantamab (1,315 nM [200 µg/mL]) with or without sBCMA (2,630 nM). All samples were quantified by Alamarblue assay. DMSO: dimethyl sulfoxide. ****P<0.0001; ***P=0.0002.