CyBorD-DARA is potent initial induction for MM and enhances ADCP: initial results of the 16-BCNI-001/CTRIAL-IE 16-02 study

Abstract

Daratumumab (DARA) has shown impressive activity in combination with other agents for the treatment of multiple myeloma (MM). We conducted a phase 1b study to assess the safety and preliminary efficacy, as well as potential mechanisms of action, of DARA (16 mg/kg) in combination with a weekly schedule of subcutaneous bortezomib (1.3-1.5 mg/m2), cyclophosphamide (150-300 mg/m2), and dexamethasone (40 mg) (CyBorD DARA) as initial induction before autologous stem cell transplantation (ASCT). Eligible patients were ≤70 years of age with untreated MM requiring treatment and who lacked significant comorbidities. A total of 18 patients were enrolled. Their median age was 56 years (range, 32-66 years), and all patients had Eastern Cooperative Oncology Group performance status ≤1. The International Staging System stages were I, II, and III in 78%, 17%, and 6% of patients, respectively; 28% of patients had high-risk genetic features. There was no dose-limiting toxicity, and the incidence of grade 3 or 4 infection or neutropenia was <10%. On an intention-to-treat basis, 94% achieved ≥very good partial response with ≥complete response in 44% of patients. Among 14 of 15 patients who underwent ASCT and were evaluable for response, all 14 achieved at least very good partial response, with 8 (57%) of 14 achieving complete response. After ASCT, 10 (83%) of 12 patients in whom minimal residual disease analysis was possible were negative at a sensitivity of 10-5 (56% on intention-to-treat/whole study population) according to next-generation sequencing. Flow cytometry analysis of patient samples indicated CyBorD DARA induced activation of macrophage-mediated antibody-dependent cellular phagocytosis. This trial was registered at www.clinicaltrials.gov as #NCT02955810.

Conflict of interest statement

Conflict-of-interest disclosure: M.O. and A.E.R. received research support from Janssen Pharmaceuticals. M.O. and J.Q. have received consultancy fees from Janssen and AbbVie. The remaining authors declare no competing financial interests.

© 2019 by The American Society of Hematology.

Figures

Graphical abstract

Figure 1.

Bone marrow mononuclear cell numbers in patients with MM before and after cyclophosphamide treatment. (A) Absolute numbers of the 3 major bone marrow subtypes were quantified by using flow cytometry in bone marrow samples from 10 adults diagnosed with MM before (pretreatment) and 24 hours after (posttreatment) with CyBorD DARA. (B) Specific CD45+ bone marrow subpopulations were identified based on side scatter characteristics and surface expression of CD14. Representative gating strategy for bone marrow aspirates for the identification and quantification of lymphocytes, neutrophils, and monocytes. (C) Graphed dot plots indicate the absolute number of lymphocytes, neutrophils, and monocytes from bone marrow aspirates before (prescreened) and 24 hours’ posttreatment with CyBorD DARA (n = 10). (D) Dot plots indicate the absolute number of CD4+ and CD8+ T cells and NK cells pretreatment and posttreatment (n = 6). Gating for subpopulation of lymphocytes is shown in supplemental Figure 1. Lines between dots indicate paired samples. Wilcoxon matched pairs signed rank test and paired Student t tests were used to detect statistically significant differences between pretreatment and posttreatment samples. *P < .05, **P < .01. FSC-A, forward scatter–area; ns, not significant; SSC-A, side scatter–area.

Figure 2.

PB mononuclear cell (PBMC) numbers in patients with MM before and after cyclophosphamide treatment. (A) Absolute numbers of the 3 major PB subtypes were quantified by using flow cytometry in blood samples from 10 adults diagnosed with MM before (pretreatment) and 24 hours after (posttreatment) with CyBorD DARA. Specific CD45+ PB subpopulations were identified based on side scatter characteristics and surface expression of CD14 (as in Figure 1B). (B) Graphed dot plots indicate the absolute number of lymphocytes, neutrophils, and monocytes from bone marrow aspirates before (prescreened) and 24 hours’ posttreatment with CyBorD DARA (n = 10). (C) Dot plots indicate the absolute number of CD4+ and CD8+ T cells and NK cells pretreatment and posttreatment (n = 6). Gating for subpopulation of lymphocytes is shown in supplemental Figure 1. Each dot represents an individual patient. Lines between dots indicate paired samples. Wilcoxon matched pairs signed rank test and paired Student t tests were used to detect statistically significant differences between pretreatment and posttreatment samples. *P < .05, **P < .01, ****P < .001. ns, not significant.

Figure 3.

Multicolor flow cytometry for the identification and expression of CD64 on PB and bone marrow monocyte subsets. (A) Representative dot plots are shown to illustrate the gating strategy for the identification of total monocytes. Monocytes were identified by CD33+CX3CR+CD56–CD14+ expression. (B) Representative histogram of CD64 expression on CD33+CX3CR+CD56-CD14+ bone marrow monocytes/macrophages from a patient with MM pretreatment and posttreatment. The black histogram is the fluorescence minus one control (FMO). The gray filled histogram identifies the pretreatment bone marrow sample, and the dotted line represents the posttreatment bone marrow sample (left). Dot plots indicate the mean fluorescence intensity of CD64 expression pretreatment and posttreatment on CD33+CX3CR+CD56–CD14+ monocytes/macrophages (n = 13) (right). (C) Representative histogram of CD64 expression on CD33+CX3CR+CD56–CD14+ PB monocytes/macrophages from a patient with MM pretreatment and posttreatment. The black histogram is the FMO. The gray filled histogram identifies the pretreatment PB sample, and the dotted line represents the posttreatment PB sample (left). Dot plots indicate the mean fluorescence intensity of CD64 expression pretreatment and posttreatment on CD33+CX3CR+CD56–CD14+ PB monocytes/macrophages (n = 13) (panel B, right). Lines between dots indicate paired samples. Wilcoxon matched pairs signed rank test and paired Student t tests were used to detect statistically significant differences between pretreatment and posttreatment samples. *P < .05, **P < .01. APC, allophycocyanin; FSC-H, forward scatter–height; MFI, mean fluorescence intensity; SSC, side scatter.

Figure 4.

Analysis of circulating proinflammatory and anti-inflammatory cytokines in MM patient serum before and after treatment with CyBorD DARA. (A) Representative scheme to illustrate the work flow for isolation and analysis of patient serum before and after treatment. (B) Dot plots indicate the levels of TNF-α (upper left, n = 12), IFN-γ (upper right, n = 12), interleukin-10 (IL-10) (lower left, n = 12), and PGE2 (lower right, n = 12) before and after treatment in MM serum samples. Lines between dots indicate paired samples. Paired Student t tests were used to detect statistically significant differences between pretreatment and posttreatment samples. *P < .05. ELISA, enzyme-linked immunosorbent assay.

Figure 5.

Multicolor flow cytometry for the identification and expression of CD47 on plasma cells pretreatment and posttreatment with CyBorD DARA. (A) Representative dot plots are shown to illustrate the gating strategy for the identification of CD138 plasma cells. Plasma cells were identified by surface expression of CD138. (B) Dot plots indicate the mean fluorescence intensity (MFI) of CD47 expression pretreatment and posttreatment on CD138 MM cells from the bone marrow (n = 5) (left) and PB (n = 5) (right). Lines between dots indicate paired samples. Wilcoxon matched pairs signed rank test and paired Student t tests were used to detect statistically significant differences between pretreatment and posttreatment samples; *P < .05.