Novel Immunotherapeutic Agents for the Treatment of Multiple Myeloma

Therapeutic strategies to enhance immune response induced by multiple myeloma cells

Multiple myeloma (MM)as a haematological malignancy is still incurable. In addition to the presence of somatic genetic mutations in myeloma patients, the presence of immunosuppressive microenvironment greatly affects the outcome of treatment. Although the discovery of immunotherapy makes it possible to break the risk of high toxicity and side effects of traditional chemotherapeutic drugs, there are still obstacles of ineffective treatment or disease recurrence. In this review, we discuss therapeutic strategies to further enhance the specific anti-tumor immune response by activating the immunogenicity of MM cells themselves. New ideas for future myeloma therapeutic approaches are provided.

Daratumumab Plus Bortezomib, Melphalan, and Prednisone Versus Bortezomib, Melphalan, and Prednisone in Transplant-Ineligible Newly Diagnosed Multiple Myeloma: Frailty Subgroup Analysis of ALCYONE

BACKGROUND

In the phase 3 ALCYONE study, daratumumab plus bortezomib/melphalan/prednisone (D-VMP) versus bortezomib/melphalan/prednisone (VMP) significantly improved progression-free survival (PFS) and overall survival (OS) in transplant-ineligible, newly diagnosed multiple myeloma (NDMM) patients. We present a subgroup analysis of ALCYONE by patient frailty status.

PATIENTS AND METHODS

Frailty assessment was performed retrospectively using age, Charlson comorbidity index, and baseline Eastern Cooperative Oncology Group performance status score. Patients were classified as fit (0), intermediate (1), or frail (≥2); a nonfrail category combined fit and intermediate patients.

RESULTS

Among randomized patients (D-VMP, n = 350; VMP, n = 356), 391 (55.4%) were nonfrail (D-VMP, 187 [53.4%]; VMP, 204 [57.3%]) and 315 (44.6%) were frail (163 [46.6%]; 152 [42.7%]). After 40.1-months median follow-up, nonfrail patients had longer PFS and OS than frail patients, but benefits of D-VMP versus VMP were maintained across subgroups: PFS nonfrail (median, 45.7 vs. 19.1 months; hazard ratio [HR], 0.36; P < .0001), frail (32.9 vs. 19.5 months; HR, 0.51; P < .0001); OS nonfrail (36-month rate, 83.6% vs. 74.5%), frail (71.4% vs. 59.0%). Improved greater than or equal to complete response and minimal residual disease (10^-5)-negativity rates were observed for D-VMP versus VMP across subgroups. The 2 most common grade 3/4 treatment-emergent adverse events were neutropenia (nonfrail: 39.2% [D-VMP] and 42.4% [VMP]; frail: 41.3% and 34.4%) and thrombocytopenia (nonfrail: 32.8% and 36.9%; frail: 36.9% and 39.1%).

CONCLUSION

Our findings support the clinical benefit of D-VMP in transplant-ineligible NDMM patients enrolled in ALCYONE, regardless of frailty status.

lncRNA transcription factor 7 is related to deteriorating clinical features and poor prognosis in multiple myeloma, and its knockdown suppresses disease progression by regulating the miR-203-mediated Jagged1-Notch1 signaling pathway

Multiple myeloma (MM) remains a challenge to treat, and its precise pathogenic mechanisms have not been fully clarified. The present study aimed to evaluate the relation between long non-coding RNA transcription factor 7 (lnc-TCF7) and clinical features, as well as the prognosis of patients with MM, and to determine the effects of lnc-TCF7-knockdown on the regulation (and regulatory mechanisms) of MM progression. lnc-TCF7 expression was detected in the bone marrow plasma cells of 86 patients with MM and 30 healthy controls. In patients with MM, the clinical data were collected, and event-free survival (EFS) and overall survival (OS) analyses were conducted. In vitro, lnc-TCF7 expression was detected in MM cell lines and normal bone marrow plasma cells. Using Roswell Park Memorial Institute 8226 cells, functional experiments were conducted following lnc-TCF7 short hairpin (sh)RNA transfection, and compensation experiments were performed after lnc-TCF7 shRNA transfection alone and in combination with a microRNA (miR)-203 inhibitor. lnc-TCF7 expression was increased in patients with MM compared with the healthy controls and was positively related to β-2-microglobulin expression and International Staging System stage, while negatively associated with complete response, EFS and OS. In vitro, lnc-TCF7 was upregulated in MM cells compared with normal bone marrow plasma cells, and its knockdown suppressed MM cell proliferation while promoting apoptosis. Compensation experiments showed that miR-203 inhibition promoted MM progression by regulating the Jagged1-Notch1 signaling pathway in lnc-TCF7-knockdown cells. In conclusion, increased lnc-TCF7 expression was related to deteriorating clinical features and prognosis, and lnc-TCF7-knockdown inhibited disease progression by regulating the miR-203-mediated Jagged1-Notch1 signaling pathway activation in MM.

Immunostimulatory oncolytic virotherapy for multiple myeloma targeting 4-1BB and/or CD40

Multiple myeloma (MM) is a plasma cell malignancy that is characterized by immune dysregulation. MM is commonly treated with immunomodulating agents, but still remains incurable. Herein, we proposed and evaluated immunostimulatory Lokon oncolytic adenoviruses (LOAd) for MM treatment. LOAd viruses are serotype 5/35 chimera, which enables infection of hematopoietic cells. Oncolysis is restricted to cells with a dysregulated retinoblastoma protein pathway, which is frequently observed in MM. Further, LOAd viruses are armed with human immunostimulatory transgenes: trimerized membrane-bound CD40L (LOAd700, LOAd703) and 4-1BBL (LOAd703). LOAd viruses were assessed in a panel of MM cell lines (ANBL-6, L363, LP-1, OPM-2, RPMI-8226, and U266-84). All cells were sensitive to infection, leading to viral replication and cell killing as analyzed by quantitative PCR and viability assay. Transgene expression was verified post infection with flow cytometry. Cell phenotypes were further altered with a downregulation of markers connected to MM progression (ICAM-1, CD70, CXCL10, CCL2, and sIL-2Rα) and an upregulation of the death receptor Fas. In a co-culture of immune and MM cells, LOAd viruses promoted activation of cytotoxic T cells as seen by higher CD69, CD107a, and IFNγ expression. This was most prominent with LOAd703. In conclusion, LOAd viruses are of interest for MM therapy.

DOT1L inhibition is lethal for multiple myeloma due to perturbation of the endoplasmic reticulum stress pathway

The histone 3 lysine 79 (H3K79) methyltransferase (HMT) DOT1L is known to play a critical role for growth and survival of MLL-rearranged leukemia. Serendipitous observations during high-throughput drug screens indicated that the use of DOT1L inhibitors might be expandable to multiple myeloma (MM). Through pharmacologic and genetic experiments, we could validate that DOT1L is essential for growth and viability of a subset of MM cell lines, in line with a recent report from another team. In vivo activity against established MM xenografts was observed with a novel DOT1L inhibitor. In order to understand the molecular mechanism of the dependency in MM, we examined gene expression changes upon DOT1L inhibition in sensitive and insensitive cell lines and discovered that genes belonging to the endoplasmic reticulum (ER) stress pathway and protein synthesis machinery were specifically suppressed in sensitive cells. Whole-genome CRISPR screens in the presence or absence of a DOT1L inhibitor revealed that concomitant targeting of the H3K4me3 methyltransferase SETD1B increases the effect of DOT1L inhibition. Our results provide a strong basis for further investigating DOT1L and SETD1B as targets in MM.

How to Train Your T Cells: Overcoming Immune Dysfunction in Multiple Myeloma

The progression of multiple myeloma, a hematologic malignancy characterized by unregulated plasma cell growth, is associated with increasing innate and adaptive immune system dysfunction, notably in the T-cell repertoire. Although treatment advances in multiple myeloma have led to deeper and more durable clinical responses, the disease remains incurable for most patients. Therapeutic strategies aimed at overcoming the immunosuppressive tumor microenvironment and activating the host immune system have recently shown promise in multiple myeloma, particularly in the relapsed and/or refractory disease setting. As the efficacy of T-cell-dependent immuno-oncology therapy is likely affected by the health of the endogenous T-cell repertoire, these therapies may also provide benefit in alternate treatment settings (e.g., precursor disease; after stem cell transplantation). This review describes T-cell-associated changes during the evolution of multiple myeloma and provides an overview of T-cell-dependent immuno-oncology approaches under investigation. Vaccine and checkpoint inhibitor interventions are being explored across the multiple myeloma disease continuum; treatment modalities that redirect patient T cells to elicit an anti-multiple myeloma response, namely, chimeric antigen receptor (CAR) T cells and bispecific antibodies [including BiTE (bispecific T-cell engager) molecules], have been primarily evaluated to date in the relapsed and/or refractory disease setting. CAR T cells and bispecific antibodies/antibody constructs directed against B-cell maturation antigen have generated excitement, with clinical data demonstrating deep responses. An increased understanding of the complex interplay between the immune system and multiple myeloma throughout the disease course will aid in maximizing the potential for T-cell-dependent immuno-oncology strategies in multiple myeloma.

Management of infectious complications in multiple myeloma patients: Expert panel consensus-based recommendations

The introduction of new therapeutic agents in multiple myeloma (MM), including proteasome inhibitors, immunoregulatory drugs and monoclonal antibodies, has improved the outcomes of patients, but in parallel has changed the frequency and epidemiology of infections. Hence, the great strides in the indications and use of new active treatments for MM need parallel progresses on the best approach to prophylaxis and supportive therapy for infections. Moving from the recognition that the above issue represents an unmet clinical need in MM, an expert panel assessed the scientific literature and composed a framework of recommendations for optimal infection control in patients candidate to active treatment for MM. The present publication represents a consensus document from questionnaires and consensus meetings held during 2017. The issues tackled in the project dealt with: infectious risk assessment, risk management and prophylaxis, intravenous immunoglobulin replacement therapy, antiviral and antibacterial vaccination. Considering the lack of conclusive and/or enough large studies for certain topics several recommendations derived from the personal experience of the experts.