Emerging combination treatment strategies containing novel agents in newly diagnosed multiple myeloma

Exploring cellular immunotherapy platforms in multiple myeloma

Despite major advances in therapeutic platforms, most patients with multiple myeloma (MM) eventually relapse and succumb to the disease. Among the novel therapeutic options developed over the past decade, genetically engineered T cells have a great deal of potential. Cellular immunotherapies, including chimeric antigen receptor (CAR) T cells, are rapidly becoming an effective therapeutic modality for MM. Marrow-infiltrating lymphocytes (MILs) derived from the bone marrow of patients with MM are a novel source of T cells for adoptive T-cell therapy, which robustly and specifically target myeloma cells. In this review, we examine the recent innovations in cellular immunotherapies, including the use of dendritic cells, and cellular tools based on MILs, natural killer (NK) cells, and CAR T cells, which hold promise for improving the efficacy and/or reducing the toxicity of treatment in patients with MM.

Current Status of Chimeric Antigen Receptor T-Cell Therapy in Multiple Myeloma

Multiple myeloma (MM) is an incurable malignancy of plasma cells. Recently multiple new therapeutic options have been introduced which was able to improve overall survival but ultimately patient become refractory specifically in patients with poor cytogenetics. Therefore, novel therapeutic options like immunotherapy are needed to improve outcomes. Chimeric antigen receptor (CAR) T-cell therapy is immunotherapy in which T cell are genetically engineered against a tumor-specific antigen and transfused back to the patient to mount major histocompatibility complex-independent cancer-specific immune response. The success of CAR T-cell therapy in lymphoid malignancies encouraged its development in MM. Most of the clinical studies target B-cell maturation antigen in relapsed refractory MM and relapse is the major issue. In this article, we will present the basics of CAR T-cell therapy, the most recent clinical and preclinical data, and we will discuss the future therapeutic realm of CAR T cells in MM.

Cellular immunotherapy in multiple myeloma

In multiple myeloma (MM), the impaired function of several types of immune cells favors the tumor's escape from immune surveillance and, therefore, its growth and survival. Tremendous improvements have been made in the treatment of MM over the past decade but cellular immunotherapy using dendritic cells, natural killer cells, and genetically engineered T-cells represent a new therapeutic era. The application of these treatments is growing rapidly, based on their capacity to eradicate MM. In this review, we summarize recent progress in cellular immunotherapy for MM and its future prospects.

Therapeutic experience of vincristine/cyclophosphamide/melphalan or mitoxantrone/prednisone combination therapy plus thalidomide as first-line induction therapy for newly diagnosed multiple myeloma in a single institution of China

INTRODUCTION

To investigate the safety and efficacy of the combination regimen vincristine, cyclophosphamide, melphalan or mitoxantrone and prednisone (VCMP) plus thalidomide as first-line induction therapy for newly diagnosed multiple myeloma (MM).

METHODS

Three hundred and ninety-six symptomatic, newly diagnosed MM patients were treated with VCMP plus thalidomide in our hospital for the past 11 years, and clinical data of these patients were retrospectively analyzed.

RESULTS

Of the 396 patients enrolled, the total response rate was 77.3%. Forty-three patients relapsed after sCR and CR. Mean cycles to first response were six cycles (range 1-16 cycles). A total of 53% of patients achieved at least a PR within the first cycle of therapy. The actuarial 1-year, 3-year and 5-year overall survival of all patients were 89.4%, 29.5% and 10.6%, respectively. The probabilities of 1-year, 3-year and 5-year progression-free survival of all patients were 84.0%, 23.1% and 8.4%, respectively. The major adverse events were gastrointestinal symptoms, electrolytes and glucose metabolism disorders, hypertension, infection, peripheral nerve disease and hematological adverse events, which were mostly below grade 3 and could be alleviated by symptomatic treatment.

CONCLUSION

We concluded that VCMP plus thalidomide is an effective regimen with manageable side effects in the treatment of symptomatic, newly diagnosed MM including elderly patients and patients with renal failure.

Subcutaneous Administration of Bortezomib in Combination with Thalidomide and Dexamethasone for Treatment of Newly Diagnosed Multiple Myeloma Patients

Objective. To investigate the efficacy and safety of the treatment of the newly diagnosed multiple myeloma (MM) patients with the therapy of subcutaneous (subQ) administration of bortezomib and dexamethasone plus thalidomide (VTD) regimen. Methods. A total of 60 newly diagnosed MM patients were analyzed. 30 patients received improved VTD regimen (improved VTD group) with the subQ injection of bortezomib and the other 30 patients received conventional VTD regimen (VTD group).The efficacy and safety of two groups were analyzed retrospectively. Results. The overall remission (OR) after eight cycles of treatment was 73.3% in the VTD group and 76.7% in the improved VTD group (P > 0.05). No significant differences in time to 1-year estimate of overall survival (72% versus 75%, P = 0.848) and progression-free survival (median 22 months versus 25 months; P = 0.725) between two groups. The main toxicities related to therapy were leukopenia, neutropenia, thrombocytopenia, asthenia, fatigue, and renal and urinary disorders. Grade 3 and higher adverse events were significantly less common in the improved VTD group (50%) than VTD group (80%, P = 0.015). Conclusions. The improved VTD regimen by changing bortezomib from intravenous administration to subcutaneous injection has noninferior efficacy to standard VTD regimen, with an improved safety profile and reduced adverse events.

Modulation of cell metabolic pathways and oxidative stress signaling contribute to acquired melphalan resistance in multiple myeloma cells

Alkylating agents are widely used chemotherapeutics in the treatment of many cancers, including leukemia, lymphoma, multiple myeloma, sarcoma, lung, breast and ovarian cancer. Melphalan is the most commonly used chemotherapeutic agent against multiple myeloma. However, despite a 70-80% initial response rate, virtually all patients eventually relapse due to the emergence of drug-resistant tumour cells. By using global proteomic and transcriptomic profiling on melphalan sensitive and resistant RPMI8226 cell lines followed by functional assays, we discovered changes in cellular processes and pathways not previously associated with melphalan resistance in multiple myeloma cells, including a metabolic switch conforming to the Warburg effect (aerobic glycolysis), and an elevated oxidative stress response mediated by VEGF/IL8-signaling. In addition, up-regulated aldo-keto reductase levels of the AKR1C family involved in prostaglandin synthesis contribute to the resistant phenotype. Finally, selected metabolic and oxidative stress response enzymes were targeted by inhibitors, several of which displayed a selective cytotoxicity against the melphalan-resistant cells and should be further explored to elucidate their potential to overcome melphalan resistance.

Results of a Phase II clinical trial with Id-protein-loaded dendritic cell vaccine in multiple myeloma: encouraging or discouraging?

Recently gained insight into the role of dendritic cells (DCs) as APCs has attracted the attention of many researchers who hope to use them as a tool in immunotherapy for the induction of tumor-specific immunity in cancer settings. Despite high expectations, in multiple myeloma patients the results of DC-based vaccines in terms of clinical response have been disappointing. The findings of Zahradova et al. in a Phase II clinical trial with multiple myeloma patients corroborated these results. Although no clinical responses were observed, the investigators induced immunity after vaccination with Id-protein-loaded DC vaccine in some patients. These immunological results showed a trend towards a longer duration of stable disease in those patients that received the vaccination. Moreover, this study showed that Id-protein-loaded DC vaccines are safe and nontoxic and that they are able to induce immunity in some patients. Therefore, standardization of vaccination protocols appears to be the key to achieving a better clinical outcome.

Anti-tumor activity against multiple myeloma by combination of KW-2478, an Hsp90 inhibitor, with bortezomib

Heat shock protein 90 (Hsp90) is a promising target for anti-tumor therapy. We previously reported the anti-tumor activity of a novel Hsp90 inhibitor, KW-2478, in multiple myeloma (MM) as a single agent. In this study, we examined the combinational effect of KW-2478 and bortezomib, a proteasome inhibitor, in vitro and in vivo. In vitro, KW-2478 enhanced bortezomib-induced cell growth inhibition, both in MM cell lines and primary patient MM cells. The combination of KW-2478 and bortezomib also induced caspase activation in MM cell lines. Interestingly, the combination synergistically enhanced the expression of Hsp70B, a homolog of Hsp70, in human MM cells and peripheral blood mononuclear cells, indicating Hsp70B could be a surrogate biomarker for the combination of Hsp90 and proteasome inhibitors. In vivo, the combination of KW-2478 with bortezomib showed synergistic anti-tumor activity without significant body weight loss in a subcutaneously inoculated human myeloma model. Furthermore, the combination also showed synergistic reduction of tumor burden in bone marrow in an orthotopic myeloma model. Our results strongly suggest that combination of KW-2478 with bortezomib could exhibit enhanced anti-tumor activity against human myeloma.

Immunotherapy using dendritic cells against multiple myeloma: how to improve?

Multiple myeloma (MM) is a good target disease in which one can apply cellular immunotherapy, which is based on the graft-versus-myeloma effect. This role of immune effector cells provides the framework for the development of immune-based therapeutic options that use antigen-presenting cells (APCs) with increased potency, such as dendritic cells (DCs), in MM. Current isolated idiotype (Id), myeloma cell lysates, myeloma dying cells, DC-myeloma hybrids, or DC transfected with tumor-derived RNA has been used for immunotherapy with DCs. Immunological inhibitory cytokines, such as TGF-β, IL-10, IL-6 and VEGF, which are produced from myeloma cells, can modulate antitumor host immune response, including the abrogation of DC function, by constitutive activation of STAT3. Therefore, even the immune responses have been observed in clinical trials, the clinical response was rarely improved following DC vaccinations in MM patients. We are going to discuss how to improve the efficacy of DC vaccination in MM.

Tracking human multiple myeloma xenografts in NOD-Rag-1/IL-2 receptor gamma chain-null mice with the novel biomarker AKAP-4

BACKGROUND

Multiple myeloma (MM) is a fatal malignancy ranking second in prevalence among hematological tumors. Continuous efforts are being made to develop innovative and more effective treatments. The preclinical evaluation of new therapies relies on the use of murine models of the disease.

METHODS

Here we describe a new MM animal model in NOD-Rag1null IL2rgnull (NRG) mice that supports the engraftment of cell lines and primary MM cells that can be tracked with the tumor antigen, AKAP-4.

RESULTS

Human MM cell lines, U266 and H929, and primary MM cells were successfully engrafted in NRG mice after intravenous administration, and were found in the bone marrow, blood and spleen of tumor-challenged animals. The AKAP-4 expression pattern was similar to that of known MM markers, such as paraproteins, CD38 and CD45.

CONCLUSIONS

We developed for the first time a murine model allowing for the growth of both MM cell lines and primary cells in multifocal sites, thus mimicking the disease seen in patients. Additionally, we validated the use of AKAP-4 antigen to track tumor growth in vivo and to specifically identify MM cells in mouse tissues. We expect that our model will significantly improve the pre-clinical evaluation of new anti-myeloma therapies.

International Myeloma Working Group consensus approach to the treatment of multiple myeloma patients who are candidates for autologous stem cell transplantation

The role of high-dose therapy followed by autologous stem cell transplantation (ASCT) in the treatment of multiple myeloma (MM) continues to evolve in the novel agent era. The choice of induction therapy has moved from conventional chemotherapy to newer regimens incorporating the immunomodulatory derivatives thalidomide or lenalidomide and the proteasome inhibitor bortezomib. These drugs combine well with traditional therapies and with one another to form various doublet, triplet, and quadruplet regimens. Up-front use of these induction treatments, in particular 3-drug combinations, has affected unprecedented rates of complete response that rival those previously seen with conventional chemotherapy and subsequent ASCT. Autotransplantation applied after novel-agent-based induction regimens provides further improvement in the depth of response, a gain that translates into extended progression-free survival and, potentially, overall survival. High activity shown by immunomodulatory derivatives and bortezomib before ASCT has recently led to their use as consolidation and maintenance therapies after autotransplantation. Novel agents and ASCT are complementary treatment strategies for MM. This article reviews the current literature and provides important perspectives and guidance on the major issues surrounding the optimal current management of younger, transplantation-eligible MM patients.

Factors influencing the outcome of a second autologous stem cell transplant (ASCT) in relapsed multiple myeloma: a study from the British Society of Blood and Marrow Transplantation Registry

Autologous stem cell transplant as primary (first ASCT) therapy in multiple myeloma (MM) is standard practice. The role of a second ASCT as management of relapsed disease remains uncertain. We conducted a retrospective case-matched control analysis on patients (n = 106) who underwent a second ASCT compared with conventional chemotherapy (CCT) as for relapsed MM. The median age was 53 years (range: 26-75) and median follow-up 48 months (range: 8, 136). The cumulative incidence of 1 and 5 years nonrelapse mortality (NRM) was 7% (95% confidence interval [CI] 3%-13%) and 12% (95% CI 7%-19%), with a second ASCT inducing a greater partial remission (PR) rate of 63%. The 4-year overall survival (OS) rate was 33% (95% CI 24%-45%). Factors associated with improved OS and progression-free survival (PFS) included younger age (<55 years), β(2)MG <2.5 mg/L at diagnosis, a remission duration of >9 months from first ASCT, and a greater PR in response to their first ASCT. In a matched-cohort analysis with patients receiving conventional chemotherapy (CCT), the same factors were associated with improved OS, with the exception of a longer remission duration (>18 months) from first ASCT. Second ASCT in relapsed MM is associated with superior OS and PFS compared with CCT, offering a potential consolidative option for selected patients.

SST0001, a chemically modified heparin, inhibits myeloma growth and angiogenesis via disruption of the heparanase/syndecan-1 axis

PURPOSE

Heparanase promotes myeloma growth, dissemination, and angiogenesis through modulation of the tumor microenvironment, thus highlighting the potential of therapeutically targeting this enzyme. SST0001, a nonanticoagulant heparin with antiheparanase activity, was examined for its inhibition of myeloma tumor growth in vivo and for its mechanism of action.

EXPERIMENTAL DESIGN

The ability of SST0001 to inhibit growth of myeloma tumors was assessed using multiple animal models and a diverse panel of human and murine myeloma cell lines. To investigate the mechanism of action of SST0001, pharmacodynamic markers of angiogenesis, heparanase activity, and pathways downstream of heparanase were monitored. The potential use of SST0001 as part of a combination therapy was also evaluated in vivo.

RESULTS

SST0001 effectively inhibited myeloma growth in vivo, even when confronted with an aggressively growing tumor within human bone. In addition, SST0001 treatment causes changes within tumors consistent with the compound's ability to inhibit heparanase, including downregulation of HGF, VEGF, and MMP-9 expression and suppressed angiogenesis. SST0001 also diminishes heparanase-induced shedding of syndecan-1, a heparan sulfate proteoglycan known to be a potent promoter of myeloma growth. SST0001 inhibited the heparanase-mediated degradation of syndecan-1 heparan sulfate chains, thus confirming the antiheparanase activity of this compound. In combination with dexamethasone, SST0001 blocked tumor growth in vivo presumably through dual targeting of the tumor and its microenvironment.

CONCLUSIONS

These results provide mechanistic insight into the antitumor action of SST0001 and validate its use as a novel therapeutic tool for treating multiple myeloma.

Novel therapeutic strategies in multiple myeloma: role of the heat shock protein inhibitors

Despite advances in understanding the molecular pathogenesis of multiple myeloma and promising new therapies, almost all patients eventually relapse with resistant disease. There is therefore a strong rationale for combining novel therapies that target intrinsic molecular pathways mediating multiple myeloma cell resistance. One such protein family is the heat shock proteins (HSP), especially the HSP90 family. Heat shock protein inhibitors have been identified as promising cancer treatments as, while they only inhibit a single biologic function, the chaperone-protein association, their effect is widespread as it results in the destruction of numerous client proteins. This article reviews the preclinical and clinical data, which support the testing of HSP90 inhibitors as cancer drugs and update the reader on the current status of the ongoing clinical trials of HSP90 inhibitors in multiple myeloma.

A defucosylated anti-CD317 antibody exhibited enhanced antibody-dependent cellular cytotoxicity against primary myeloma cells in the presence of effectors from patients

The humanized monoclonal antibody (mAb) against CD317 antigen (anti-HM1.24 antibody; AHM), which is highly expressed on multiple myeloma (MM), induces antibody-dependent cellular cytotoxicity (ADCC). However, the antitumor activity of AHM in the clinical setting has not been clearly demonstrated. In this study, we produced defucosylated AHM and evaluated its potency for clinical application by performing autologous ADCC assays against primary MM cells from patients. Defucosylated AHM that was produced in rat myeloma YB2/0 cells expressing a low level of fucosyltransferase (FUT8) showed significant ADCC activity against three out of six primary MM cells in the presence of autologous PBMC, whereas conventional AHM did not. The results indicate that the potency of AHM to induce ADCC against primary MM cells was insufficient, but was significantly augmented by defucosylation. To generate more homogenous defucosylated monoclonal antibodies (mAb) for fermentation, we disrupted the GFT gene that encodes a GDP-fucose transporter in a CHO/DXB11 cell line by sequential homologous recombination. Analysis of the N-linked oligosaccharide in the defucosylated AHM produced by the established GFT(-/-)CHO cell line showed that a majority (93.4%) of the oligosaccharide was fucose free. The GFT(-/-) cells stably produced defucosylated mAb over passages. These results demonstrate that GTF(-/-)CHO-produced defucosylated AHM (GFTKO-AHM) will be a promising new therapeutic antibody against MM in the clinical setting.

Bortezomib, thalidomide, and dexamethasone as induction therapy for patients with symptomatic multiple myeloma: a retrospective study

BACKGROUND

This single-center retrospective study determined the efficacy of bortezomib, thalidomide, and dexamethasone (BTD) as induction for patients with multiple myeloma (MM) who were eligible for autologous stem cell transplantation (ASCT).

METHODS

Patients with symptomatic MM who had received BTD induction before stem cell collection at Winship Cancer Institute were included. BTD induction comprised up to 8 3-week cycles of bortezomib 1.3 mg/m(2) on Days 1, 4, 8, and 11; thalidomide 100 mg daily; and dexamethasone 40 mg on Days 1 through 4 and Days 9 through 12. Stem cell mobilization involved granulocyte-colony-stimulating factor and/or cyclophosphamide. Response was assessed according to European Group for Blood and Marrow Transplantation criteria.

RESULTS

Review of medical records identified 44 eligible patients (34 patients who were treated in the front-line setting and 10 patients who were treated for recurrent disease) who received a median of 4 BTD cycles. The overall response rate (ORR) was 91%, which included a greater than or equal to very good partial response (> or = VGPR) rate of 57% (including 20% stringent complete responses/complete response [sCR/CR] rate). In front-line patients, the ORR was 94%, which included a 56% > or = VGPR rate (24% sCR/CR). The median CD34-positive stem cell collection was 10.67 x 10(6)/kg. The ORR after ASCT in 34 patients who were evaluable for response was 100%, including a 76% > or = VGPR rate (53% sCR/CR). Among all 44 patients, the median progression-free survival (PFS) was 27.4 months. The median overall survival (OS) was not reached after a median follow-up of 25 months, and the 2-year OS rate was 82%. There were no significant differences in PFS (27.4 months vs 23.5 months) or in 2-year survival (80% vs 90%) between patients who did and did not undergo ASCT, respectively. Twenty patients (45%) developed neuropathy, including 4 (9%) with grade 3 neuropathy episodes, and 1 patient developed deep vein thrombosis.

CONCLUSIONS

BTD was highly effective and well tolerated as induction for MM patients who were eligible for ASCT. Long-term outcomes appeared to be similar with or without ASCT consolidation.

Alpha-type 1-polarized dendritic cells loaded with apoptotic allogeneic myeloma cell line induce strong CTL responses against autologous myeloma cells

To induce a potent cytotoxic T lymphocyte (CTL) response, various tumor antigens should be loaded onto dendritic cells (DCs). In multiple myeloma (MM), it is difficult to obtain a sufficient number of autologous tumor cells as a source of tumor antigens in the clinical setting. We investigated the feasibility of immunotherapy in patients with MM, using myeloma-specific CTLs generated in vitro by alpha-type 1-polarized DCs (alphaDC1s) loaded with the ultraviolet B-irradiated allogeneic myeloma cell line, ARH77. alphaDC1s significantly increased the expression of several costimulatory molecules without differences in loading with tumor antigens. alphaDC1s showed a high production of interleukin-12 during maturation and after subsequent stimulation with CD40L but were not significantly affected by loading tumor antigens. Myeloma-specific CTLs against autologous myeloma cells from MM patients were induced by alphaDC1s pulsed with apoptotic ARH77 cells. Our data indicate that autologous DCs loaded with an allogeneic myeloma cell line can generate potent myeloma-specific CTL responses against autologous myeloma cells and might provide a practical method for cellular immunotherapy in patients with MM.