Correlative analysis of biomarker data in the bone marrow of patients with R/R MM treated with modakafusp alfa. Box and whisker plots (whiskers 10-90 percentile) depict percent of CD38 receptors occupied on viable leukocytes of the bone marrow (A); fold change in the type 1 interferon gene signature score in the bone marrow as defined by the average FPKM of 25 interferon-stimulated genes (B); fold change in CD38 density on NK cells of the bone marrow (C); myeloma cells of the bone marrow (D); and T cells of the bone marrow (E). Baseline for all data sets was defined as the sample collected during screening. Because of limited sampling of the bone marrow, C1D16, C2D2, C3D2, and C4D2 were evaluated for statistical significance together because all assessments were planned 24 hours (±2 days) after modakafusp alfa was administered. A linear regression model was used to evaluate the trend of DR. Wilcoxon signed-rank test was used to determine whether pooled data from all doses were significantly changed from baseline. A significant ΔBL was defined as a fold change of ≥1.5 above, or ≤2/3 below, baseline for cellular markers (panels A,C-E); similarly, for gene expression (panel B), a significant ΔBL was defined as a fold change of ≥2 or ≤1/2. The ΔBL thresholds are shaded in gray on each panel as applicable. DR and ΔBL P values are depicted above data sets. ΔBL, change from baseline; C, cycle; D, day; DR, dose responsiveness; IFN, interferon; ISG, interferon-stimulated gene; n.s., nonsignificant result; SSC, side scatter.