Immunotherapy In Multiple Myeloma Research Articles

AFM26 - Targeting B Cell Maturation Antigen (BCMA) for NK Cell-Mediated Immunotherapy of Multiple Myeloma

Significant progress in multiple myeloma (MM) treatment has been made in recent years and achieving sustained minimal residual disease (MRD) negativity now constitutes a major goal of treatment. High dose melphalan combined with autologous stem cell transplantation (ASCT) is currently regarded the standard of care in 1st line treatment of MM in eligible patients, but fails to eradicate MRD in the majority of patients ultimately leading to disease relapse. Consequently, additional therapies are needed to target residual disease to delay or potentially prevent relapse.The cell surface antigen B cell maturation antigen (BCMA, CD269) constitutes a highly attractive target antigen for immunotherapy because of its restricted expression in non-malignant tissue but almost universal expression on MM cells.AFM26 is a BCMA-targeted tetravalent bispecific antibody that selectively engages natural killer (NK) cells to induce myeloma cell lysis. Through its high-affinity bivalent binding to CD16A (FcγRIIIa), AFM26 possesses prolonged cell retention times, and has been shown to be less prone to interference by high levels of circulating IgG than antibody Fc-domains. Thus, AFM26 can be used to “arm” NK cells for effective killing of tumor cells. AFM26 also induces markedly lower levels of pro-inflammatory cytokines in peripheral blood mononuclear cell (PBMC) cultures in the presence of target cells compared to BCMA-directed T cell activating approaches. In contrast to other monoclonal antibodies (mAbs) such as daratumumab and elotuzumab, AFM26 does not confer target-independent NK cell activation or NK cell depletion.NK cells are promising effectors to target MRD. Due to their early reconstitution following ASCT and their ability to rapidly destroy malignant cells through direct cytotoxicity. Redirecting NK cells through AFM26 may therefore offer an effective treatment of MM patients early after ASCT.Employing a wide range of functional assays, we demonstrate here that AFM26 exhibits potent cytotoxic activity against primary myeloma cells using patient (autologous) and donor-derived (allogeneic) NK cells as well as against a panel of high and low BCMA expressing cell lines. In particular, we show that AFM26 induces NK cell cytotoxicity towards cells expressing almost undetectable surface levels of BCMA, suggesting the potential for broad and deep anti-MM activity. In summary, AFM26 is well-differentiated from other mAbs and a promising therapeutic candidate to address the unmet medical need of MRD positivity in MM. DisclosuresGantke:Affimed: Employment. Reusch:Affimed: Employment. Kellner:Affimed: Research Funding. Klausz:Affimed: Research Funding. Haneke:Affimed: Employment. Knackmuss:Affimed: Employment. Müller:Affimed: Employment. Ellwanger:Affimed: Employment. Fucek:Affimed: Employment. Schniegler-Mattox:Affimed: Employment. Koch:Affimed: Employment. Kerber:Affimed: Employment. Peipp:Affimed: Research Funding. Treder:Affimed: Employment.

FABP5, a Novel Immune-Related mRNA Prognostic Marker and a Target of Immunotherapy for Multiple Myeloma.

Objective: Multiple myeloma is an incurable hematological malignancy. It is imperative to identify immune markers for early diagnosis and therapy. Here, this study analyzed immune-related mRNAs and assessed their prognostic value and therapeutic potential.Methods: Abnormally expressed immune-related mRNAs were screened between multiple myeloma and normal bone marrow specimens in the GSE47552 and GSE6477 datasets. Their biological functions were then explored. Survival analysis was presented for assessing prognosis-related mRNAs. CIBERSORT was utilized for identifying 22 immune cell compositions of each bone marrow specimen. Correlation between FABP5 mRNA and immune cells was then analyzed in multiple myeloma.Results: Thirty-one immune-related mRNAs were abnormally expressed in multiple myeloma, which were primarily enriched in B cells-related biological processes and pathways. Following validation, FABP5 mRNA was a key risk factor of multiple myeloma. Patients with its up-regulation usually experienced unfavorable outcomes. There were distinct differences in the infiltration levels of B cells naïve, B cells memory, plasma cells, T cells CD4 naïve, resting memory CD4 T cells, activated memory CD4 T cells, Tregs, resting NK cells, M0 macrophages, M1 macrophages, M2 macrophages, and neutrophils between multiple myeloma and normal samples. FABP5 mRNA had correlations to B cells memory, B cells naïve, dendritic cells activated, macrophages M0, macrophages M1, macrophages M2, neutrophils, activated NK cells, resting memory CD4 T cells, CD8 T cells and Tregs.Conclusion: Collectively, our data showed that FABP5 mRNA was related to immune microenvironment, which could be a target of immunotherapy and prognostic marker for multiple myeloma.

Rapid Progress in Immunotherapies for Multiple Myeloma: An Updated Comprehensive Review.

Simple SummaryDespite rapid advances in the development of novel agents over the last decade for the treatment of multiple myeloma (MM), MM remains an incurable disease. Therefore, the development of novel targeting therapies with different mechanisms of action is needed to achieve a deep and durable response for the cure of MM. Recently, an antibody-drug conjugate (ADC), belanatmab mafadotin, which targets B cell membrane antigen (BCMA) on plasma cells, was approved for the treatment of relapsed or refractory MM in 2020. To date, immunotherapies including bi-specific or tri-specific antibodies, adoptive cellular therapy using autologous chimeric antigen (CAR)-T cells, allogeneic CAR-natural killer (NK) cells, and checkpoint inhibitors have been developed for MM, and a variety of clinical trials are currently underway or planned. This review presents an update on the most recent clinical and preclinical advances with a focus on results from clinical trials in progress with BCMA-targeted immunotherapies or the development of other novel targets in MM.Despite rapid advances in treatment approaches of multiple myeloma (MM) over the last two decades via proteasome inhibitors (PIs), immunomodulatory drugs (IMiDs), and monoclonal antibodies (mAbs), their efficacies are limited. MM still remains incurable, and the majority of patients shortly relapse and eventually become refractory to existing therapies due to the genetic heterogeneity and clonal evolution. Therefore, the development of novel therapeutic strategies with different mechanisms of action represents an unmet need to achieve a deep and highly durable response as well as to improve patient outcomes. The antibody-drug conjugate (ADC), belanatmab mafadotin, which targets B cell membrane antigen (BCMA) on plasma cells, was approved for the treatment of MM in 2020. To date, numerous immunotherapies, including bispecific antibodies, such as bispecific T cell engager (BiTE), the duobody adoptive cellular therapy using a dendritic cell (DC) vaccine, autologous chimeric antigen (CAR)-T cells, allogeneic CAR-natural killer (NK) cells, and checkpoint inhibitors have been developed for the treatment of MM, and a variety of clinical trials are currently underway or are expected to be planned. In the future, the efficacy of combination approaches, as well as allogenic CAR-T or NK cell therapy, will be examined, and promising results may alter the treatment paradigm of MM. This is a comprehensive review with an update on the most recent clinical and preclinical advances with a focus on results from clinical trials in progress with BCMA-targeted immunotherapies and the development of other novel targets in MM. Future perspectives will also be discussed.

Facts and Hopes in Multiple Myeloma Immunotherapy.

Among the hallmarks of cancer is the ability of neoplastic cells to evade and suppress immune surveillance to allow their growth and evolution. Nowhere is this as apparent as in multiple myeloma, a cancer of antibody-producing plasma cells, where a complex interplay between neoplastic cells and the immune microenvironment is required for the development and progression of disease. Decades of research has led to the discovery of a number of therapeutic agents, from cytotoxic drugs to genetically engineered cells that mediate their antimyeloma effects at least partially through altering these immune interactions. In this review, we discuss the history of immunotherapy and current practices in multiple myeloma, as well as the advances that promise to one day offer a cure for this deadly disease.

Small-molecule HDAC and Akt inhibitors suppress tumor growth and enhance immunotherapy in multiple myeloma

BackgroundMultiple myeloma (MM) is an incurable disease. The acquisition of resistance to drugs, including immunomodulatory drugs (IMiDs), has a negative effect on its prognosis. Cereblon (CRBN) is a key mediator of the bioactivities of IMiDs such as lenalidomide. Moreover, genetic alteration of CRBN is frequently detected in IMiD-resistant patients and is considered to contribute to IMiD resistance. Thus, overcoming resistance to drugs, including IMiDs, is expected to improve clinical outcomes. Here, we examined potential mechanisms of a histone deacetylase (HDAC) inhibitor and Akt inhibitor in relapsed/refractory MM patients.MethodsWe established lenalidomide-resistant cells by knocking down CRBN with RNAi-mediated downregulation or knocking out CRBN using CRISPR-Cas9 in MM cells. Additionally, we derived multi-drug (bortezomib, doxorubicin, or dexamethasone)-resistant cell lines and primary cells from relapsed/refractory MM patients. The effects of HDAC and Akt inhibitors on these drug-resistant MM cells were then observed with a particular focus on whether HDAC inhibitors enhance immunotherapy efficacy. We also investigated the effect of lenalidomide on CRBN-deficient cells.ResultsThe HDAC inhibitor suppressed the growth of drug-resistant MM cell lines and enhanced the antibody-dependent cellular cytotoxicity (ADCC) of therapeutic antibodies by upregulating natural killer group 2D (NKG2D) ligands in MM cells. CRBN-deficient cells showed lenalidomide-induced upregulation of phosphorylated glycogen synthase kinase-3 (p-GSK-3) and c-Myc phosphorylation. Moreover, HDAC and Akt inhibitors downregulated c-Myc by blocking GSK-3 phosphorylation. HDAC and Akt inhibitors also exhibited synergistic cytotoxic and c-Myc-suppressive effects. The dual HDAC and PI3K inhibitor, CUDC-907, exhibited cytotoxic and immunotherapy-enhancing effects in MM cells, including multi-drug-resistant lines and primary cells from lenalidomide-resistant patients.ConclusionsThe combination of an HDAC and an Akt inhibitor represents a promising approach for the treatment of relapsed/refractory MM.

A simple method to distinguish residual elotuzumab from monoclonal paraprotein in immunofixation assays for multiple myeloma patients

Negative immunofixation electrophoresis (IFE) of serum and/or urine is a diagnostic marker for determining a complete response (CR) after immunotherapy for multiple myeloma (MM). However, residual therapeutic antibodies such as elotuzumab (IgG-κ), can compromise IFE evaluation when the affected immunoglobulins belong to the same IgG-κ subclass. We thus sought to develop a simple and rapid method to treat patient serum before IFE to distinguish the residual elotuzumab. Serum samples from patients receiving elotuzumab were treated with a predetermined amount of soluble signaling lymphocyte activation molecule F7 (SLAMF7) protein and then subjected to conventional IFE testing. We tested our method in samples from 12 patients. The IgG-κ band in IFE disappeared or shifted after elotuzumab treatment in four patients with no bone marrow minimal residual disease and normalized free light chain, whereas seven patients with any sign of residual MM showed a remaining IgG-κ band after treatment. One-hour incubation of samples with 6-9 molar excess soluble SLAMF7 before IFE was sufficient to distinguish residual elotuzumab in 11 of 12 samples. This simple method does not require special reagents, can be performed in most clinical laboratories, and enables differentiation between patients with a CR and those requiring further treatment.

Combinatorial targeting of multiple myeloma by complementing T cell engaging antibody fragments

Bispecific T cell engaging antibodies (BiTEs) address tumor associated antigens that are over-expressed on cancer but that can also be found on healthy tissues, causing substantial on-target/off-tumor toxicities. To overcome this hurdle, we recently introduced hemibodies, a pair of complementary antibody fragments that redirect T cells against cancer-defining antigen combinations. Here we show that hemibodies addressing CD38 and SLAMF7 recruit T cells for the exquisite elimination of dual antigen positive multiple myeloma cells while leaving single antigen positive bystanders unharmed. Moreover, CD38 and SLAMF7 targeting BiTEs, but not hemibodies induce massive cytokine release and T cell fratricide reactions, a major drawback of T cell recruiting strategies. Together, we provide evidence in vitro and in vivo that hemibodies can be developed for the effective and highly specific immunotherapy of multiple myeloma.

Current status and future prospects of immunotherapy for multiple myeloma

The introduction of autologous stem cell transplantation, proteasome inhibitors, and immunomodulatory drugs (IMiDs) has improved the treatment outcome for multiple myeloma (MM). However, many patients develop resistance to existing therapies, and novel treatment strategies for these patients must be established. Therapeutic antibodies including daratumumab targeting CD38 and elotuzumab targeting SLAMF7 have been introduced in the clinic as immunotherapies for MM. These antibodies exert cytotoxic effects on myeloma cells through the activation of effector cells such as natural killer cells and induction of phagocytosis by macrophages. Suppressed anti-tumor immunity may be related to acquisition of drug resistance by myeloma cells in patients with MM. It has been reported that IMiDs such as lenalidomide and pomalidomide enhance the effect of therapeutic antibodies through the stimulation of anti-tumor immunity. This stimulation of anti-tumor immunity is also observed in the effects of anti-CD38 antibodies, such as daratumumab and isatuximab. Therefore, it is expected that combination therapy with anti-CD38 antibodies and IMiDs may enhance anti-tumor immunity. Furthermore, chimeric antigen receptor (CAR) T cell therapy, antibody drug conjugates (ADC), and bispecific antibodies (BsAbs) are in the process of their introduction to the clinic as novel immunotherapies for MM.

Immunotherapy in multiple myeloma

Despite available therapies, Multiple Myeloma (MM) remains an incurable hematologic malignancy. Over the past three decades, there have been tremendous developments in therapeutic options for MM. In regards to immunotherapy, Daratumumab was the first monoclonal antibody to receive FDA approval for multiple myeloma. Since then, other monoclonal antibodies such as elotuzumab and isatuximab have received FDA approval. Many clinical trials are underway investigating the efficacy of newer immunotherapies. This review summarizes recently presented and/or published data regarding this growing field, specifically regarding monoclonal antibodies, antibody-drug conjugates, bispecific antibodies, and trispecific antibodies.

Potential Treatment for Multiple Myeloma: Immune Checkpoint Inhibitors

Multiple myeloma (MM) is a malignant disease in which monoclonal plasma cells proliferate abnormally. The poor prognosis of MM is always closely related to the immunosuppression of T cells. Restore the immune function of suppressed T cells may reverse the immunodeficiency in the MM microenvironment and improve prognosis. In recent years, immunosuppressive receptors such as programmed cell death receptor-1 (PD-1), T cells immunoglobulin and ITIM domain (TIGIT), Lymphocyte-Activation Gene-3 (LAG-3), T cell immunoglobulin and mucin domain–containing molecule 3 (Tim-3), Leukocyte immunoglobulin-like receptor B1 (LILRB1) and Cytotoxic T- lymphocyte antigen 4 (CTLA-4) have been discovered playing a key role in the tumor immunodeficiency microenvironment. For patients with solid tumors and some leukemia, immunotherapy targeting such receptors can significantly improve the T cells immunodeficiency. However, similar positive results were not found in MM patients, which is related to the complex immunosuppressive mechanism. At present, the understanding of immunosuppressive receptors in MM is insufficient. In this review, this paper summarized part of the studies on PD-1, TCLA-4, Tim-3, TIGIT and other popular immunosuppressive receptors in MM, in order to attract more attention, and in-depth research on the immunotherapy also to promote the immunotherapy of MM from basic research to clinical transformation as soon as possible.

Curation of a Multiple Myeloma Cell Surface Database for Immunotherapy Development

Background/Objective: Every year in the United States, 32,000 individuals are diagnosed with Multiple Myeloma (MM) and 13,000 die from the disease. MM is a cancer of the plasma cells and while treatment exists, MM remains incurable. Our overall goal is to identify biologically and therapeutically relevant cell surface targets to develop MM immunotherapy. 
 
 Methods: Given the genomic heterogeneity of MM, we performed surface analysis of seven MM cell lines by Mass-Spectrometry (MS), generating a pool of candidate proteins. Lacking specific tools for studying cell surface proteins, we developed an integrated computational tool with five distinct databases, and scored the likelihood of cell surface location for each molecule. One point was given for each database a protein appeared in. A protein receiving a score of three or more was considered a cell surface protein with high confidence. However, about one third of the candidates were not detected by the computational tool, thus requiring manual curation. We used UniProt and GeneCards to determine the subcellular locations of the unannotated IDs, and further confirmed their location with the computational tool. 
 
 Results: Of the 5,454 UniProt IDs produced by MS, 2,026 were not annotated. Causes of an unannotated ID included having an obsolete ID, being an isoform, and/or not being located on the cell surface. Through manual annotation, 8 unique cell surface IDs were added to the existing 448. The 456 targets were further analyzed based on their expression profiles in both MM and normal tissues resulting in 94 of the most promising targets, some of which would have been missed without manual curation. 
 
 Conclusion/Potential Impact: Public genomic databases are often incomplete and may contain errors making manual curation a necessary step in error reduction. Left unchecked, promising surface targets could have been overlooked hindering the creation of potentially curative immunotherapies.

Targeting NK Cell Inhibitory Receptors for Precision Multiple Myeloma Immunotherapy.

Innate immune surveillance of cancer involves multiple types of immune cells including the innate lymphoid cells (ILCs). Natural killer (NK) cells are considered the most active ILC subset for tumor elimination because of their ability to target infected and malignant cells without prior sensitization. NK cells are equipped with an array of activating and inhibitory receptors (IRs); hence NK cell activity is controlled by balanced signals between the activating and IRs. Multiple myeloma (MM) is a hematological malignancy that is known for its altered immune landscape. Despite improvements in therapeutic options for MM, this disease remains incurable. An emerging trend to improve clinical outcomes in MM involves harnessing the inherent ability of NK cells to kill malignant cells by recruiting NK cells and enhancing their cytotoxicity toward the malignant MM cells. Following the clinical success of blocking T cell IRs in multiple cancers, targeting NK cell IRs is drawing increasing attention. Relevant NK cell IRs that are attractive candidates for checkpoint blockades include KIRs, NKG2A, LAG-3, TIGIT, PD-1, and TIM-3 receptors. Investigating these NK cell IRs as pathogenic agents and therapeutic targets could lead to promising applications in MM therapy. This review describes the critical role of enhancing NK cell activity in MM and discusses the potential of blocking NK cell IRs as a future MM therapy.

Cite-Seq Profiling of T Cells in Multiple Myeloma Patients Undergoing BCMA Targeting CAR-T or Bites Immunotherapy

Adaptive T cell therapy using chimeric antigen receptor (CAR) T cells and bispecific T cell engagers (BiTEs) have demonstrated encouraging responses in heavily pre-treated multiple myeloma (MM) patients. However, the cellular and molecular predictors of clinical response are not fully understood as well as the mediators of acquired resistance remain elusive. Local immune suppression and T cell exhaustion are important mediators of responses therefore, it is plausible to speculate that a tolerant tumor microenvironment and the expansion of specific T cell populations may dictate clinical responses. In this study, we performed at the single cell level a broad immunophenotypic and transcriptomic characterization of the blood and bone marrow (BM) T cells of sensitive and resistant MM patients treated with adaptive T cell therapies. Using cellular indexing of transcriptomes and epitopes by sequencing (CITE-seq) we measured the expansion of variable T cell subsets, T cell specific activation and inhibitor markers and their functional states in order to identify cellular mediators of resistance to these adoptive immune therapies. Serial blood samples and BM aspirates (n=12) were collected from patients treated with anti-BCMA CAR-T or BCMA-CD3 BiTEs at variable time points, prior and post initiation of therapy and at relapse. Bone marrow mononuclear fractions were isolated through ficoll density gradients coupled with magnetic sorting of CD3pos T cells. Unbiased mRNA profiling coupled with feature barcoding technology for cell surface protein (TotalSeq-B) of BM CD3pos T cells was then performed by using the chromium single cell (10x Genomics). Paired-end sequencing was performed on Illumina platform. Cell Ranger and Seurat pipeline were used for sample de-multiplexing, barcode processing, single-cell 3′ gene counting, cell surface protein expression and data analysis. CAR-T cells were identified by the expression of the chimeric CAR-T cell transcript. The parallel measurement of transcripts and cell surface protein phenotypes of CD3pos T cells using a panel of 19 immune surface markers underlined the T cell repertoire diversity and identified different T cell subsets among the CD8pos and CD4pos T cells. Notably, the cell surface protein information overlaid on the transcript-generated UMA allowed accurate identification of all main immune clusters, in particular for the CD45RA and CD45RO positive cells. Comparison of CITE-Seq features revealed that the T cells composition of the blood and BM niches differed significantly between sensitive and resistant patients. As such an enrichment of CD4pos T cells with a higher CD4:CD8 ratio was noted in responding patients. Phenotypic (CD45RA, CD45RO, CD95, CCR7, CD62L, CD28, CD27) and transcriptional signatures (TCF7, LEF1, GATA3, EOMES, TBX21, PRDM1) also identified a higher proportion of memory like T cells (Tscm, Tcm) in responding patients. In contrast, T cells of resistant patients were enriched with terminally exhausted (Tex) and senescent cells with loss of CD28, high GMZHand GMZB, CD57pos, CD69pos and CD160pos as well as upregulation of TBX21. Expression of T cell checkpoint inhibitors such as LAG3, TIGIT and PD1 was high in these Tex cells as well as in some Tem. Of note, ex vivo T cell activation studies with TIGIT blockade demonstrated T cell activation in an autologous MM and T cell co-culture system with enhanced MM cells death. An expanded cluster of regulatory T cells (Treg) FOXP3pos,CD25pos was also observed in two resistant patients. Of note, no loss of BCMA transcript or surface expression was noted in MM cells at the time of acquired resistance. Single cell transcriptome of primary MM cells and chromatin accessibility (ATAC-seq) analyses of T cells of these patients are ongoing to investigate the transcriptional programs and epigenetic factors underlying the immune escape. Combined single cell features profiling of the transcriptome and surface protein expression of T cells from MM patients receiving BCMA targeted CAR-T or BiTEs therapies revealed potential mediators of resistance. In particular, T cells composition (low CD4:CD8 ratio and reduced population of Tscm, Tcm) along with an enrichment of terminally exhausted T cells are the main features observed in resistant patients. Delineating these mechanisms will guide future T cells engineering studies to enhance the efficacy and response durability of adoptive immunotherapy in MM. Disclosures McCulloch: Amgen: Honoraria; Sanofi: Honoraria; Celgene: Honoraria; Janssen: Honoraria. Duggan:Jannsen: Consultancy; Amgen: Consultancy; Novartis: Honoraria; Celgene: Consultancy; Astra Zeneca: Consultancy. Jimenez-Zepeda:Janssen, Celgene, Amgen, Takeda: Honoraria. Bahlis:AbbVie: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; GSK: Consultancy, Honoraria; Genentech: Consultancy, Honoraria; BMS/Celgene and Janssen: Consultancy, Honoraria, Other: Travel, Accomodations, Research Funding; Karyopharm Therapeutics: Consultancy, Honoraria; Sanofi: Consultancy, Honoraria. Neri:Celgene/BMS: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Amgen: Consultancy, Honoraria.

Translational Approach of Using Ex Vivo Cytotoxicity and Early Clinical Data to Predict Teclistamab Efficacious Therapeutic Range in Multiple Myeloma Patients

B cell maturation antigen (BCMA; CD269; TNFRSF17) is a surface receptor, expressed on benign and malignant plasma cells. The restricted expression of BCMA on B-cell lineage makes it an ideal target for multiple myeloma (MM) immunotherapy. BCMAxCD3 bispecific antibody (Teclistamab; JNJ-64007957) has been developed to recruit CD3+ T-cells to BCMA+ MM cells. Teclistamab demonstrated potent cytotoxicity in a murine xenograft model and against ex vivo primary MM cells. Teclistamab clinical starting dose in the first in human (FIH) study in relapsed refractory MM patients began at the minimal anticipated biological effect level (MABEL) of 0.3 µg/kg using the EC20 of the in vitro cytotoxicity assay in the purified T cells model with MM.1R cell line. Since the MABEL dose is usually low, it is important to have guidance on the expected therapeutic range in patients. The therapeutic concentrations of teclistamab were estimated from an ex vivo cytotoxicity assay in which samples from MM patients (frozen purified mononuclear cells from bone marrow) were treated with healthy human purified T cells (1:1 ratio) spiked with teclistamab and incubated for 48 hours. The mean and range of EC50 and EC90 values of the cytotoxicity endpoint were estimated. The pharmacokinetic (PK) data following the first cycle doses in the low dose cohorts in the FIH study in MM patients were modeled using 2-compartment model and simulated to predict the doses that will have average and trough serum teclistamab concentrations in the expected therapeutic range (between EC50 and EC90). The predicted doses with average serum concentrations between the mean EC50 (372 ng/mL) and mean EC90 (2287 ng/mL) range were validated with the observed clinical data showing positive response in 2 out of 4 patients at the 38.4 µg/kg intravenous treatment dose level and their average serum teclistamab concentration overlaid within the estimated therapeutic range. This was also confirmed with the teclistamab concentrations in bone marrow samples (measured in a subset of MM patients in the study) where they were found to superimpose in the estimated therapeutic range. In addition, simulations predicted the dose that will have trough levels above the maximum EC90 (6070 ng/mL), to account for patients with high tumor burden, at which the observed clinical data have shown promising response rate and has been selected to be the recommended subcutaneous phase 2 dose of 1500 µg/kg. In conclusion, ex vivo cytotoxicity assay with MM patients bone marrow samples is an informative tool to predict the efficacious serum concentration of immuno-oncology drugs in MM patients. PK modeling and simulations of MM patients' data in FIH study coupled with the ex vivo cytotoxicity estimates provided guidance on the expected recommended phase 2 dose during the escalation phase of the FIH study. Disclosures Girgis: Johnson & Johnson: Current Employment, Current equity holder in publicly-traded company. Wang Lin:Johnson & Johnson: Current Employment. Pillarisetti:Johnson & Johnson: Current Employment. Banerjee:Janssen: Current Employment. Goldberg:Johnson & Johnson: Current Employment, Current equity holder in publicly-traded company. Shetty:Johnson & Johnson: Current Employment. Stephenson:Johnson & Johnson: Current Employment, Current equity holder in private company. Hilder:Johnson & Johnson: Current Employment, Current equity holder in publicly-traded company. Hanna:Johnson & Johnson: Current Employment, Current equity holder in publicly-traded company. Smit:Johnson & Johnson: Current Employment, Current equity holder in publicly-traded company. Adams III:Genmab: Current Employment. Sun:Johnson & Johnson: Current Employment, Current equity holder in publicly-traded company. Infante:Janssen: Current Employment. Elsayed:Johnson & Johnson: Current Employment. Sharma:Johnson & Johnson: Current Employment.

Three Drug Combinations in the Treatment of Fit Elderly Multiple Myeloma Patients.

The multiple myeloma (MM) non transplant eligible (NTE) population is growing in line with the aging of the population in Western countries. Historically, this population has been known for having a greater risk of treatment related toxicity, and therefore drug development was slow and rather oriented towards the improvement of safety profile than the optimization of disease control. However, NTE MM patients, at least for the fit/non frail patients in recent years, seemed to have benefited more from a less palliative care to improve the depth of response and then prolong survival. NTE MM being a quite heterogeneous population, there are still a number of groups of patients that are in need of more efficient therapy, avoiding unnecessary toxicity, particularly for the frail patients. The use of triplet regimen with a melphalan-prednisone (MP) backbone has long been the standard of care for NTE MM, often dedicated to non-frail patients. New standards of care, triplet, and even quadruplet combinations, are emerging on the basis of the MP backbone but also on the more recently approved lenalidomide-dexamethasone (Rd) backbone. These developments were largely possible in line with the development of antibody-based immunotherapies (IT) in MM. The objective to improve outcomes with an acceptable safety profile will see other key therapeutic developments such as the dropping of dexamethasone early in the disease course or various attempts to allow permanent treatment discontinuation with a prolonged disease control. In that context, it is possible that immunomonitoring, minimal residual disease (MRD), and genomic risk-adaptation will become key elements of the treatment decisions on triplet-based regimens.

Immunotherapy in multiple myeloma: when, where, and for who?

Immunotherapy is transforming treatment of multiple myeloma patients in all stages of their disease. This review will discuss recent developments in immunotherapy in multiple myeloma with a focus on antibodies, antibody-drug conjugates, and T-cell-redirection strategies. CD38-targeting antibodies have single agent activity in multiple myeloma, and especially when combined with other drugs, are improving the clinical outcome of patients with newly diagnosed or relapsed/refractory multiple myeloma. Also the SLAMF7-targeting antibody, elotuzumab, improves the survival of relapsed/refractory multiple myeloma patients, when it is combined with either lenalidomide or pomalidomide. Several novel immunotherapies, such as chimeric antigen receptor T cells, antibody-drug conjugates, and bispecific antibodies, are active in patients who developed resistance to all currently available antimultiple myeloma drugs, including immunomodulatory drugs, proteasome inhibitors, and CD38 antibodies. These new immunotherapeutic agents frequently target B-cell maturation antigen, which is highly and uniformly expressed on multiple myeloma cells. However, other targets, such as GPRC5D, are also being investigated. Immunotherapy is incorporated into first-line and relapse regimens, and is improving the survival of both newly diagnosed and relapsed/refractory multiple myeloma patients.

Abstract 5630: Anti-BCMA bispecific tool therapy against Vk*MYC multiple myeloma is enhanced by IMiDs

Abstract BCMA is an ideal target antigen for myeloma immunotherapy as it is specifically expressed by plasma cells and T cell-engaging, BCMA-bispecific antibodies show potent tumor killing activity in human multiple myeloma (MM). However, a lack of longevity, potential immunotoxicity, and efficacy in high tumor burden situations are limitations to effective clinical utility. In order to optimize this therapeutic approach, we performed in vitro and in vivo assessments of a BCMA bispecific tool using the Vk*MYC immunocompetent mouse model of MM. Analysis at gene and protein level revealed variable levels of BCMA in Vk*MYC tumors, mirroring the heterogeneity of BCMA observed in human MM. In addition, we found that treatment with a gamma secretase inhibitor enhanced BCMA expression in Vk*MYC MM cells, similar to observations from patients. Having found the Vk*MYC model as a suitable model for BCMA targeted therapy, we treated Vk*MYC de novo and transplant mice with the BCMA targeting tool and established that the treatment was safe and efficacious (significant reduction in M-spike levels compared to control antibody). However, the response was transient and modest activity was noted in high tumor burden setting, likely because of poor T cell infiltration. Therefore, we hypothesized that combining BCMA therapy with agents capable of debulking the tumors would prolong and deepen therapeutic benefits and thus selected IMiDs for their anti-tumor and immunomodulatory properties. Because mice are resistant to therapy with IMiDs, we generated a humanized transgenic mouse strain with robust human CRBN expression and crossed it with the Vk*MYC mouse to obtain a novel immunocompetent, IMiD-responsive model, Vk*MYChCRBN. When combined with the IMiD pomalidomide (POM), bispecific-directed T cell control of MM was enhanced relative to bispecific alone. M-spike levels in two different transplantable models were reduced regardless of tumor burden. In addition, POM increased T cell effector activation, proliferation, and cytokine production. We also monitored transient weight loss unique to the bispecific-POM combination. Following this promising combinatorial result in vivo, we studied the relative roles of POM on target vs. effector cells by an in vitro killing assay using Vk*MYC tumor and splenocytes with or without expression of CRBN. Separately from the direct tumoricidal effects of POM on the tumor, we observed T cell-intrinsic effects of POM on the enhancement of BCMA-bispecific directed tumor lysis that correlated with T cell activation and proliferation. In summary, POM potentiated BCMA-CD3 bispecific directed T cell cytolysis of MM in the Vk*MYChCRBN animal model by enhancing effector cell activation, proliferation, cytokine production and directly reducing tumor burden. These results support ongoing preclinical studies of the benefits of combining standard of care therapy with potent T cell immunotherapy for MM. Citation Format: Erin W. Meermeier, Meaghen E. Sharik, Seth J. Welsh, Caleb K. Stein, Victoria M. Garbitt, Sochilt Brown, Kennedi T. Todd, Marco Bergsagel, P. Leif Bergsagel, Marta Chesi. Anti-BCMA bispecific tool therapy against Vk*MYC multiple myeloma is enhanced by IMiDs [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 5630.

NY-ESO-1 Protein Vaccine Combining Alum, CpG ODN, and HH2 Complex Adjuvant Induces Protective and Therapeutic Anti-Tumor Responses in Murine Multiple Myeloma.

BackgroundNY-ESO-1 is an ideal target for multiple myeloma immunotherapy. Alum, CpG ODN and HH2 complex is a safe and effective adjuvant for cancer vaccine.MethodsWe constructed NY-ESO-1 protein vaccine combined with alum, CpG ODN, and HH2 complex adjuvant to immunize the BALB/c mice inoculated with NS-1 murine multiple myeloma cells. Then, we determined the immunogenicity and anti-tumor effects in prophylactic and therapeutic models by analyzing the NY-ESO-1 antibody titer, evaluating IL4/INF-γ expression, and assessing cytotoxic T lymphocytes activities. The side-effects of vaccines were also evaluated.ResultsThe group of NY-ESO-1 protein vaccine combining alum, CpG ODN, and HH2 complex adjuvant is more capable of stimulating both humoral and cellular tumor-specific immune responses to prolong the survival of the mice and inhibit tumor growth in prophylactic and therapeutic immunotherapy. The marked side-effects were not detected in immunized mice.DiscussionThe results suggest that alum, CpG ODN, and HH2 complex as a novel immune adjuvant combined cancer vaccine could improve the immunity efficiency in a murine multiple myeloma model.

CRISPR-based screens uncover determinants of immunotherapy response in multiple myeloma

AbstractCancer cells commonly develop resistance to immunotherapy by loss of antigen expression. Combinatorial treatments that increase levels of the target antigen on the surface of cancer cells have the potential to restore efficacy to immunotherapy. Here, we use our CRISPR interference– and CRISPR activation–based functional genomics platform to systematically identify pathways controlling cell surface expression of the multiple myeloma immunotherapy antigen B-cell maturation antigen (BCMA). We discovered that pharmacologic inhibition of HDAC7 and the Sec61 complex increased cell surface BCMA, including in primary patient cells. Pharmacologic Sec61 inhibition enhanced the antimyeloma efficacy of a BCMA-targeted antibody-drug conjugate. A CRISPR interference chimeric antigen receptor T cells (CAR-T cells) coculture screen enabled us to identify both antigen-dependent and antigen-independent mechanisms controlling response of myeloma cells to BCMA-targeted CAR-T cells. Thus, our study shows the potential of CRISPR screens to uncover mechanisms controlling response of cancer cells to immunotherapy and to suggest potential combination therapies.

Multiagent therapy with pomalidomide, bortezomib, doxorubicin, dexamethasone, and daratumumab (“Pom‐PAD‐Dara”) in relapsed/refractory multiple myeloma

BackgroundEven in the era of novel immunotherapies for multiple myeloma (MM), treatment of late‐stage relapsed/refractory (RR) patients remains challenging. The aim of our study was to analyze the efficacy and safety of the five‐drug combination pomalidomide, bortezomib, doxorubicin, dexamethasone, and daratumumab (“Pom‐PAD‐Dara”) in RRMM.MethodsWe retrospectively analyzed data of 56 patients with RRMM who received Pom‐PAD‐Dara between September 2016 and May 2019.ResultsPatients were heavily pretreated with a median of four prior lines of therapy, including autologous and allogenic stem cell transplant in 50 (89%) and six (11%) patients, respectively. The overall response rate (ORR) was 78% and we observed partial remission, very good partial remission, and complete remission in 27 (48%), 13 (23%) and four (7%) patients, respectively. Median progression‐free survival was 7 months (95% CI, 3.3‐10.7) and the median overall survival was not reached at 24 months. Adverse events grade ≥ 3 were observed 41 (73%) patients and included neutropenia (n = 28, 50%), anemia (n = 22, 39%), thrombocytopenia (n = 21, 38%), and pneumonia (n = 6, 11%).ConclusionPom‐PAD‐Dara represents a promising multiagent regimen in heavily pretreated RRMM patients with high ORR and an acceptable safety profile.