Preclinical rationale for targeting the PD‐1/PD‐L1 axis in combination with a CD38 antibody in multiple myeloma and other CD38‐ positive malignancies

The CD38‐targeting antibody daratumumab mediates its anti‐myeloma activities not only through Fc‐receptor‐dependent effector mechanisms, but also by its effects on T‐cell immunity through depletion of CD38+ regulatory T‐cells, regulatory B‐cells, and myeloid‐derived suppressor cells. Therefore, combining daratumumab with modulators of other potent immune inhibitory pathways, such as the PD‐1/PD‐L1 axis, may further improve its efficacy. We show that multiple myeloma (MM) cells from relapsed/refractory patients have increased expression of PD‐L1, compared to newly diagnosed patients. Furthermore, PD‐1 is upregulated on T‐cells from both newly diagnosed and relapsed/refractory MM patients, compared to healthy controls. In short‐term experiments with bone marrow samples from MM patients, daratumumab‐mediated lysis was mainly associated with the MM cells’ CD38 expression levels and the effector (NK-cells/monocytes/T‐cells)‐to‐target ratio, but not with the PD‐L1 expression levels or PD‐1+ T‐cell frequencies. Although PD‐1 blockade with nivolumab did not affect MM cell viability or enhanced daratumumab‐mediated lysis in short‐term ex vivo experiments, nivolumab resulted in a mild but clear increase in T‐cell numbers. Moreover, with a longer treatment duration, PD‐1 blockade markedly improved anti‐CD38 antibody‐mediated cytotoxicity in vivo in murine CD38+ tumor models. In conclusion, dual targeting of CD38 and PD‐1 may represent a promising strategy for treating MM and other CD38‐positive malignancies

Functional MYCN signature predicts outcome of neuroblastoma irrespective of MYCN amplification

Neuroblastoma is a pediatric tumor of the sympathetic nervous system. MYCN (V-myc myelocytomatosis viral-related oncogene, neuroblastoma derived [avian]) is amplified in 20% of neuroblastomas, and these tumors carry a poor prognosis. However, tumors without MYCN amplification also may have a poor outcome. Here, we identified downstream targets of MYCN by shRNA-mediated silencing MYCN in neuroblastoma cells. From these targets, 157 genes showed an expression profile correlating with MYCN mRNA levels in NB88, a series of 88 neuroblastoma tumors, and therefore represent in vivo relevant MYCN pathway genes. This 157-gene signature identified very poor prognosis tumors in NB88 and independent neuroblastoma cohorts and was more powerful than MYCN amplification or MYCN expression alone. Remarkably, this signature also identified poor outcome of a group of tumors without MYCN amplification. Most of these tumors have low MYCN mRNA levels but high nuclear MYCN protein levels, suggesting stabilization of MYCN at the protein level. One tumor has an MYC amplification and high MYC expression. Chip-on-chip analyses showed that most genes in this signature are directly regulated by MYCN. MYCN induces genes functioning in cell cycle and DNA repair while repressing neuronal differentiation genes. The functional MYCN-157 signature recognizes classical neuroblastoma with MYCN amplification, as well as a newly identified group marked by MYCN protein stabilizatio

Anti-human Vascular Endothelial Growth Factor (VEGF) Antibody Selection for Immunohistochemical Staining of Proliferating Blood Vessels

Nine commercially available vascular endothelial growth factor (VEGF) antibodies were investigated for their ability to immunostain vascular malformations (VMs) with or without immature capillary proliferation. First, all antibodies were optimized for their performance in IHC, with placenta and colon adenocarcinoma as positive control tissues. Five antibodies were regarded as unfit for VEGF immunostaining based on poor immunostaining criteria. Subsequently, Western blot analysis using VEGF rabbit polyclonal antibody (Thermo RB-9031) revealed a clear 45-kDa band in tissue extracts from VMs with immature capillary proliferation and a high Ki67-labeling index, whereas tissue extracts from mature VMs without microvascular proliferation and no Ki67-labeling index demonstrated only a very weak 45-kDa band. In contrast, two VEGF antibodies, including the popular Santa Cruz A-20, revealed bands at 45 kDa of similar intensity in tissue extracts from both types of VMs. Staining characteristics of the 45-kDa band were reflected in the results obtained in IHC. (J Histochem Cytochem 58:109–118, 2010

T-cell redirecting bispecific antibodies targeting BCMA for the treatment of multiple myeloma

B-cell maturation antigen (BCMA)-targeting bispecific antibodies and bispecific T-cell engagers (BiTEs) redirect T-cells to BCMA-expressing multiple myeloma (MM) cells. These MM cells are subsequently eliminated via various mechanisms of action including the release of granzymes and perforins. Several phase 1, dose-escalation studies show pronounced activity of BCMA-targeting bispecific antibodies, including teclistamab, AMG420 and CC-93269, in heavily pretreated MM patients. Cytokine release syndrome is the most common adverse event, which can be adequately managed with tocilizumab or steroids. Several clinical trials are currently evaluating combination therapy with a BCMA-specific bispecific antibody, based on preclinical findings showing that immunomodulatory drugs or CD38-targeting antibodies enhance the activity of bispecific antibodies. In addition, bispecific antibodies, targeting other MM cell surface antigens (i. e. GPRC5D, CD38 and FcRH5), are also evaluated in early phase clinical trials. Such bispecific antibodies, targeting other antigens, may be given to patients with low baseline BCMA expression, disease with substantial heterogeneity in BCMA expression, following prior BCMA-targeted therapy, or combined with BCMA bispecific antibodies to prevent development of antigen escape

CD38-targeting antibodies in multiple myeloma: mechanisms of action and clinical experience

INTRODUCTION: Multiple myeloma (MM) is generally an incurable hematological malignancy with heterogeneous overall survival rates ranging from a few months to more than 10 years. Survival is especially poor for patients who developed disease that is refractory to immunomodulatory drugs and proteasome inhibitors. Areas covered: This review will discuss the importance of CD38-targeting antibodies for the treatment of MM patients to improve their outcome. Expert commentary: Intense immuno-oncological laboratory research has resulted in the development of functionally active monoclonal antibodies against cell surface markers present on MM cells. In this respect, CD38-targeting antibodies such as daratumumab, MOR202, and isatuximab, have high single agent activity in heavily pretreated MM patients by virtue of their pleiotropic mechanisms of action including Fc-dependent effector mechanisms and immunomodulatory activities. Importantly, CD38-targeting antibodies are well tolerated, with infusion reactions as most frequent adverse event. Altogether, this makes them attractive combination partners with other anti-MM agents. Daratumumab is already approved as monotherapy and in combination with lenalidomide-dexamethasone as well as bortezomib-dexamethasone in pretreated MM patients. Furthermore, results from studies evaluating CD38-targeting antibodies in newly diagnosed MM patients are also promising, indicating that CD38-targeting antibodies will be broadly used in MM, resulting in further improvements in survival

A NOTCH feed-forward loop drives reprogramming from adrenergic to mesenchymal state in neuroblastoma

Neuroblastoma includes adrenergic and mesenchymal cell types that can interconvert. Here, the authors show that this transdifferentiation is driven by a NOTCH feedforward loop that allows a swift transition between two semi-stable cellular states

Preclinical activity and determinants of response of the GPRC5DxCD3 bispecific antibody talquetamab in multiple myeloma

Cell surface expression levels of GPRC5D, an orphan G protein-coupled receptor, are significantly higher on multiple myeloma (MM) cells, compared with normal plasma cells or other immune cells, which renders it a promising target for immunotherapeutic strategies. The novel GPRC5D-targeting T-cell redirecting bispecific antibody, talquetamab, effectively kills GPRC5D+ MM cell lines in the presence of T cells from both healthy donors or heavily pretreated MM patients. In addition, talquetamab has potent anti-MM activity in bone marrow (BM) samples from 45 patients, including those with high-risk cytogenetic aberrations. There was no difference in talquetamab-mediated killing of MM cells from newly diagnosed, daratumumab-naïve relapsed/refractory (median of 3 prior therapies), and daratumumab-refractory (median of 6 prior therapies) MM patients. Tumor cell lysis was accompanied by T-cell activation and degranulation, as well as production of pro-inflammatory cytokines. High levels of GPRC5D and high effector:target ratio were associated with improved talquetamab-mediated lysis of MM cells, whereas an increased proportion of T cells expressing PD-1 or HLA-DR, and elevated regulatory T-cell (Treg) counts were associated with suboptimal killing. In cell line experiments, addition of Tregs to effector cells decreased MM cell lysis. Direct contact with bone marrow stromal cells also impaired the efficacy of talquetamab. Combination therapy with daratumumab or pomalidomide enhanced talquetamab-mediated lysis of primary MM cells in an additive fashion. In conclusion, we show that the GPRC5D-targeting T-cell redirecting bispecific antibody talquetamab is a promising novel antimyeloma agent. These results provide the preclinical rationale for ongoing studies with talquetamab in relapsed/refractory MM

Preclinical Activity of JNJ-7957, a Novel BCMA ×CD3 Bispecific Antibody for the Treatment of Multiple Myeloma, Is Potentiated by Daratumumab

Purpose: Multiple myeloma (MM) patients with disease refractory to all available drugs have a poor outcome, indicating the need for new agents with novel mechanisms of action. Experimental Design: We evaluated the anti-MM activity of the fully human BCMA_CD3 bispecific antibody JNJ-7957 in cell lines and bone marrow (BM) samples. The impact of several tumorand host-related factors on sensitivity to JNJ-7957 therapy was also evaluated. Results: We show that JNJ-7957 has potent activity against 4 MM cell lines, against tumor cells in 48 of 49 BM samples obtained from MM patients, and in 5 of 6 BM samples obtained from primary plasma cell leukemia patients. JNJ- 7957 activity was significantly enhanced in patients with prior daratumumab treatment, which was partially due to enhanced killing capacity of daratumumab-exposed effector cells. BCMA expression did not affect activity of JNJ-7957. High T-cell frequencies and high effector:target ratios were associated with improved JNJ-7957-mediated lysis of MM cells. The PD-1/ PD-L1 axis had a modest negative impact on JNJ-7957 activity against tumor cells from daratumumab-naïve MM patients. Soluble BCMA impaired the ability of JNJ-7957 to kill MM cells, although higher concentrations were able to overcome this negative effect. Conclusions: JNJ-7957 effectively kills MM cells ex vivo, including those from heavily pretreated MM patients, whereby several components of the immunosuppressive BM microenvironment had only modest effects on its killing capacity. Our findings support the ongoing trial with JNJ-7957 as single agent and provide the preclinical rationale for evaluating JNJ-7957 in combination with daratumumab in MM

Monocytes and Granulocytes Reduce CD38 Expression Levels on Myeloma Cells in Patients Treated with Daratumumab

Purpose: Daratumumab treatment results in a marked reduction of CD38 expression on multiple myeloma cells. The aim of this study was to investigate the clinical implications and the underlying mechanisms of daratumumab-mediated CD38 reduction.Experimental Design:We evaluated the effect of daratumumab alone or in combination with lenalidomide-dexamethasone, on CD38 levels of multiple myeloma cells and nontumor immune cells in the GEN501 study (daratumumab monotherapy) and the GEN503 study (daratumumab combined with lenalidomide-dexamethasone).In vitroassays were also performed.Results:In both trials, daratumumab reduced CD38 expression on multiple myeloma cells within hours after starting the first infusion, regardless of depth and duration of the response. In addition, CD38 expression on nontumor immune cells, including natural killer cells, T cells, B cells, and monocytes, was also reduced irrespective of alterations in their absolute numbers during therapy. In-depth analyses revealed that CD38 levels of multiple myeloma cells were only reduced in the presence of complement or effector cells, suggesting that the rapid elimination of CD38highmultiple myeloma cells can contribute to CD38 reduction. In addition, we discovered that daratumumab-CD38 complexes and accompanying cell membrane were actively transferred from multiple myeloma cells to monocytes and granulocytes. This process of trogocytosis was also associated with reduced surface levels of some other membrane proteins, including CD49d, CD56, and CD138.Conclusions:Daratumumab rapidly reduced CD38 expression levels, at least in part, through trogocytosis. Importantly, all these effects also occurred in patients with deep and durable responses, thus excluding CD38 reduction alone as a mechanism of daratumumab resistance.The trials were registered at www.clinicaltrials.gov as NCT00574288 (GEN501) and NCT1615029 (GEN503).Clin Cancer Res; 23(24); 7498-511. ©2017 AACR