HexaBody-DR5/DR5 induces selective MM cell kill in BM samples of MM patients. (A) Kill (%) by HexaBody-DR5/DR5 (20 µg/mL; n = 48) and IgG1-DR5/DR5 (n = 39) in a 24-hour assay with BMMCs from MM patients. Tumor cells were identified as CD38⁺CD138⁺. ****P < .0001, Wilcoxon matched-pairs signed-rank test. (B) Pearson’s correlation of DR5 surface expression level on MM cells with HexaBody-DR5/DR5–induced cytotoxicity (n = 46). (C) MM cell kill (%) by HexaBody-DR5/DR5 compared with kill of immune cell populations present in the BM of MM patients. n = 35. ****P < .0001, MM vs all subsets, Wilcoxon matched-pairs signed-rank test. Horizontal lines denote the median, and error bars indicate the interquartile range. B, B cells; Mono, monocytes; NK, NK cells; T, T cells.