Vorinostat or placebo in combination with bortezomib in patients with multiple myeloma (VANTAGE 088): a multicentre, randomised, double-blind study

The role of DNA damage and repair in decitabine-mediated apoptosis in multiple myeloma

DNA methyltransferase inhibitors (DNMTi) and histone deacetylase inhibitors (HDACi) are under investigation for the treatment of cancer, including the plasma cell malignancy multiple myeloma (MM). Evidence exists that DNA damage and repair contribute to the cytotoxicity mediated by the DNMTi decitabine. Here, we investigated the DNA damage response (DDR) induced by decitabine in MM using 4 human MM cell lines and the murine 5T33MM model. In addition, we explored how the HDACi JNJ-26481585 affects this DDR. Decitabine induced DNA damage (gamma-H2AX foci formation), followed by a G0/G1- or G2/M-phase arrest and caspase-mediated apoptosis. JNJ-26481585 enhanced the anti-MM effect of decitabine both in vitro and in vivo. As JNJ-26481585 did not enhance decitabine-mediated gamma-H2AX foci formation, we investigated the DNA repair response towards decitabine and/or JNJ-26481585. Decitabine augmented RAD51 foci formation (marker for homologous recombination (HR)) and/or 53BP1 foci formation (marker for non-homologous end joining (NHEJ)). Interestingly, JNJ-26481585 negatively affected basal or decitabine-induced RAD51 foci formation. Finally, B02 (RAD51 inhibitor) enhanced decitabine-mediated apoptosis. Together, we report that decitabine-induced DNA damage stimulates HR and/or NHEJ. JNJ-26481585 negatively affects RAD51 foci formation, thereby providing an additional explanation for the combinatory effect between decitabine and JNJ-26481585.

Combination of proteasome and HDAC inhibitor enhances HPV16 E7-specific CD8+ T cell immune response and antitumor effects in a preclinical cervical cancer model

Background

Bortezomib, a proteasome inhibitor and suberoylanilide hydroxamic acid (SAHA, also known as Vorinostat), a histone deacetylase inhibitor, have been recognized as potent chemotherapeutic drugs. Bortezomib and SAHA are FDA-approved for the treatment of cutaneous T cell lymphoma and multiple myeloma/mantle cell lymphoma, respectively. Furthermore, the combination of the bortezomib and SAHA has been tested in a variety of preclinical models and in clinical trials and may be ideal for the treatment of cancer. However, it remains unclear how this treatment strategy affects the host immune response against tumors.

Results

Here, we used a well-defined E6/E7-expressing tumor model to examine how the immune system can be motivated to act against tumor cells expressing tumor antigens. We demonstrate that the combination of bortezomib and SAHA elicits potent antitumor effects in TC-1 tumor-bearing mice. Additionally, we are the first to show that treatment with bortezomib and SAHA leads to tumor-specific immunity by rendering tumor cells more susceptible to killing by antigen-specific CD8+ T cells than treatment with either drug alone.

Conclusions

The current study serves an important foundation for the future clinical application of both drugs for the treatment of cervical cancer.

Electronic supplementary material

The online version of this article (doi:10.1186/s12929-014-0111-1) contains supplementary material, which is available to authorized users.

How the flexibility of human histone deacetylases influences ligand binding: an overview

Over the past decade, human histone deacetylases (HDACs) have become interesting as therapeutic targets because of the benefits that their modulation might provide in aging-related disorders. Recently, studies using crystallography and computational chemistry have provided information on the structure and conformational changes related to HDAC-mediated recognition events. Through the description of the key mass and one-off movements observed in metal-dependent HDACs, here we highlight the impact of flexibility on drug-binding affinity and specificity. The collected information will be useful for not only a better understanding of the biological functions of HDACs, but also the conception of new selective binders.

How I treat relapsed myeloma

Multiple myeloma (MM) is a plasma cell malignancy leading to significant life-expectancy shortening. Although the incorporation of the novel agents thalidomide, bortezomib, and lenalidomide in the front-line therapy has resulted in significant improvement, almost all patients relapse, making the treatment of relapse a real challenge. In the present article, when and how to treat relapsed MM is discussed. Treatment can be safely delayed in a subset of patients with asymptomatic relapse, whereas those with symptomatic relapse, advanced disease at diagnosis, or significant paraproteinemic increase require prompt rescue therapy. The benefit of retreatment and the use of a sequential approach for successive relapses considering drug synergism are highlighted. For patients with aggressive relapses and for those who have exhausted all available options, continued therapy until disease progression is recommended, particularly when using regimens with a long-term safety profile. Patients with a duration response to a first autologous stem cell transplantation (ASCT) longer than 2 years may benefit from a second ASCT. Patients with aggressive disease and/or poor cytogenetics at diagnosis relapsing within the first 2 years from ASCT should be considered for an allogeneic transplantation. Finally, a number of newer promising drugs are being actively investigated and the enrolment of patients in clinical trials is encouraged.

Current and potential epigenetic targets in multiple myeloma

Despite recent advances in therapy, subgroups of multiple myeloma continue to have a poor prognosis. Numerous epigenetic changes have been described and occur as both etiologic and secondary events, making myeloma a good disease in which to understand the role of epigenetic therapies. Here, we describe a number of current and potential epigenetic targets in myeloma.

Emerging Therapeutic Strategies for Overcoming Proteasome Inhibitor Resistance

The debut of the proteasome inhibitor bortezomib (Btz; Velcade®) radically and immediately improved the treatment of multiple myeloma (MM), an incurable malignancy of the plasma cell. Therapeutic resistance is unavoidable, however, and represents a major obstacle to maximizing the clinical potential of the drug. To address this challenge, studies have been conducted to uncover the molecular mechanisms driving Btz resistance and to discover new targeted therapeutic strategies and combinations that restore Btz activity. This review discusses the literature describing molecular adaptations that confer Btz resistance with a primary disease focus on MM. Also discussed are the most recent advances in therapeutic strategies that overcome resistance, approaches that include redox-modulating agents, murine double minute 2 inhibitors, therapeutic monoclonal antibodies, and new epigenetic-targeted drugs like bromodomain and extra terminal domain inhibitors.

Clinical use of proteasome inhibitors in the treatment of multiple myeloma

Multiple myeloma (MM) is an incurable hematological malignancy characterized by the clonal proliferation of neoplastic plasma cells. The use of proteasome inhibitors in the treatment of MM has led to significant improvements in outcomes. This article reviews data on the use of the two approved proteasome inhibitors (bortezomib and carlfilzomib), as well as newer agents under development. Emphasis is placed on the clinical use of proteasome inhibitors, including management of side effects and combination with other agents.

Multiple myeloma: a model for scientific and clinical progress

Multiple myeloma (MM) is a unique cancer paradigm for investigating the mechanisms involved in the transition from a premalignant condition (monoclonal gammopathy of undetermined significance) into a malignant disease (MM). In the pathogenesis of myeloma, the dialogue between plasma cells and their microenvironment is as important as the genotypic characteristics of the tumor clone. MM is genetically highly complex, with almost all patients displaying cytogenetic abnormalities and frequent intraclonal heterogeneity that play a critical role in the outcome of the disease. In fact, it is likely that myeloma will soon no longer be considered as a single entity. This, along with the availability of an unexpected number of new treatment possibilities, has reinforced the need for better tools for prognosis and for monitoring treatment efficacy through minimal residual disease techniques. The outcome of MM patients has significantly improved in the last 2 decades, first through the introduction of high-dose therapy followed by autologous stem cell transplantation and, more recently, due to the use of proteasome inhibitors (bortezomib and carfilzomib) and immunomodulatory agents (thalidomide, lenalidomide, and pomalidomide). Moreover, the need to reexamine the diagnostic criteria of early MM and the possibility of early intervention opens up new therapeutic avenues. New drugs are also emerging, including second- and third-generation proteasome inhibitors and immunomodulators, monoclonal antibodies, histone deacetylase inhibitors, and kinesin spindle protein inhibitors, among others. Our goal is to find a balance among efficacy, toxicity, and cost, with the ultimate aim of achieving a cure for this disease.

Targeting the integrated networks of aggresome formation, proteasome, and autophagy potentiates ER stress‑mediated cell death in multiple myeloma cells

The inhibitory effects of macrolide antibiotics including clarithromycin (CAM) on autophagy flux have been reported. Although a macrolide antibiotic exhibits no cytotoxicity, its combination with bortezomib (BZ), a proteasome inhibitor, for the simultaneous blocking of the ubiquitin (Ub)-proteasome and autophagy-lysosome pathways leads to enhanced multiple myeloma (MM) cell apoptosis induction via stress overloading of the endoplasmic reticulum (ER). As misfolded protein cargo is recruited by histone deacetylase 6 (HDAC6) to dynein motors for aggresome transport, serving to sequester misfolded proteins, we further investigated the cellular effects of targeting proteolytic pathways and aggresome formation concomitantly in MM cells. Pronounced apoptosis was induced by the combination of vorinostat [suberoylanilide hydroxamic acid (SAHA); potently inhibits HDAC6] with CAM and BZ compared with each reagent or a 2-reagent combination. CAM/BZ treatment induced vimentin positive-aggresome formation along with the accumulation of autolysosomes in the perinuclear region, whereas they were inhibited in the presence of SAHA. The SAHA/CAM/BZ combination treatment maximally upregulated genes related to ER stress including C/EBP homologous protein (CHOP). Similarly to MM cell lines, enhanced cytotoxicity with CHOP upregulation following SAHA/CAM/BZ treatment was shown by a wild-type murine embryonic fibroblast (MEF) cell line; however, a CHOP-deficient MEF cell line almost completely canceled this pronounced cytotoxicity. Knockdown of HDAC6 with siRNA exhibited further enhanced CAM/BZ-induced cytotoxicity and CHOP induction along with the cancellation of aggresome formation. Targeting the integrated networks of aggresome, proteasome, and autophagy is suggested to induce efficient ER stress-mediated apoptosis in MM cells.

Panobinostat: a review of trial results and future prospects in multiple myeloma

Multiple myeloma is an incurable often devastating disease that is responsible for 1-2% of all cancers. Multiple myeloma is the second most common hematologic malignancy. Over the past two decades, advances in therapy have doubled life expectancy. Unfortunately, all patients ultimately relapse. Novel agents (immunomodulatory drugs and proteasome inhibitors) have changed the outlook for patients, but further breakthroughs are needed. Epigenetic treatments offer potential for advancing therapy by modifying oncogene responses. The acetylation status of various proteins can affect the availability of chromatin for transcription. This response may be modulated epigenetically to advantage using histone deacetylase inhibitors like panobinostat.

Understanding biology to tackle the disease: Multiple myeloma from bench to bedside, and back

Multiple myeloma (MM) is a cancer of antibody-producing plasma cells. The pathognomonic laboratory finding is a monoclonal immunoglobulin or free light chain in the serum and/or urine in association with bone marrow infiltration by malignant plasma cells. MM develops from a premalignant condition, monoclonal gammopathy of undetermined significance (MGUS), often via an intermediate stage termed smoldering multiple myeloma (SMM), which differs from active myeloma by the absence of disease-related end-organ damage. Unlike MGUS and SMM, active MM requires therapy. Over the past 6 decades, major advancements in the care of MM patients have occurred, in particular, the introduction of novel agents (ie, proteasome inhibitors, immunomodulatory agents) and the implementation of hematopoietic stem cell transplantation in suitable candidates. The effectiveness and good tolerability of novel agents allowed for their combined use in induction, consolidation, and maintenance therapy, resulting in deeper and more sustained clinical response and extended progression-free and overall survival. Previously a rapidly lethal cancer with few therapeutic options, MM is the hematologic cancer with the most novel US Food and Drug Administration-approved drugs in the past 15 years. These advances have resulted in more frequent long-term remissions, transforming MM into a chronic illness for many patients.

Retrospective matched-pairs analysis of bortezomib plus dexamethasone versus bortezomib monotherapy in relapsed multiple myeloma

Bortezomib-dexamethasone is widely used for relapsed myeloma in routine clinical practice, but comparative data versus single-agent bortezomib are lacking. This retrospective analysis compared second-line treatment with bortezomib-dexamethasone and bortezomib using 109 propensity score-matched pairs of patients treated in three clinical trials: MMY-2045, APEX, and DOXIL-MMY-3001. Propensity scores were estimated using logistic regression analyses incorporating 13 clinical variables related to drug exposure or clinical outcome. Patients received intravenous bortezomib 1.3 mg/m(2) on days 1, 4, 8, and 11, in 21-day cycles, alone or with oral dexamethasone 20 mg on the days of/after bortezomib dosing. Median bortezomib cumulative dose (27.02 and 28.60 mg/m(2)) and treatment duration (19.6 and 17.6 weeks) were similar with bortezomib-dexamethasone and bortezomib, respectively. The overall response rate was higher (75% vs. 41%; odds ratio=3.467; P<0.001), and median time-to-progression (13.6 vs. 7.0 months; hazard ratio [HR]=0.394; P=0.003) and progression-free survival (11.9 vs. 6.4 months; HR=0.595; P=0.051) were longer with bortezomib-dexamethasone versus bortezomib, respectively. Rates of any-grade adverse events, most common grade 3 or higher adverse events, and discontinuations due to adverse events appeared similar between the groups. Two patients per group died of treatment-related adverse events. These data indicate the potential benefit of bortezomib-dexamethasone compared with single-agent bortezomib at first relapse in myeloma. The MMY-2045, APEX, and DOXIL-MMY-3001 clinical trials were registered at, respectively, clinicaltrials.gov identifier: 00908232, 00048230, and 00103506.

Novel targeted agents in the treatment of multiple myeloma

New, next-generation targeted treatment strategies are required to improve outcomes in patients with multiple myeloma (MM). Monoclonal antibodies, cell signaling inhibitors, and selective therapies targeting the bone marrow microenvironment have demonstrated encouraging results with generally manageable toxicity in therapeutic trials of patients with relapsed and refractory disease, each critically informed by preclinical studies. A combination approach of these newer agents with immunomodulators and/or proteasome inhibitors as part of a treatment platform seems to improve the efficacy of anti-MM regimens, even in heavily pretreated patients. Future studies are required to better understand the complex mechanisms of drug resistance in MM.

European perspective on multiple myeloma treatment strategies in 2014

The treatment of multiple myeloma has undergone significant changes and has resulted in the achievement of molecular remissions, the prolongation of remission duration, and extended survival becoming realistic goals, with a cure being possible in a small but growing number of patients. In addition, nowadays it is possible to categorize patients more precisely into different risk groups, thus allowing the evaluation of therapies in different settings and enabling a better comparison of results across trials. Here, we review the evidence from clinical studies, which forms the basis for our recommendations for the management of patients with myeloma. Treatment approaches depend on "fitness," with chronological age still being an important discriminator for selecting therapy. In younger, fit patients, a short three drug-based induction treatment followed by autologous stem cell transplantation (ASCT) remains the preferred option. Consolidation and maintenance therapy are attractive strategies not yet approved by the European Medicines Agency, and a decision regarding post-ASCT therapy should only be made after detailed discussion of the pros and cons with the individual patient. Two- and three-drug combinations are recommended for patients not eligible for transplantation. Treatment should be administered for at least nine cycles, although different durations of initial therapy have only rarely been compared so far. Comorbidity and frailty should be thoroughly assessed in elderly patients, and treatment must be adapted to individual needs, carefully selecting appropriate drugs and doses. A substantial number of new drugs and novel drug classes in early clinical development have shown promising activity. Their introduction into clinical practice will most likely further improve treatment results.

Combined autophagy and proteasome inhibition: a phase 1 trial of hydroxychloroquine and bortezomib in patients with relapsed/refractory myeloma

The efficacy of proteasome inhibition for myeloma is limited by therapeutic resistance, which may be mediated by activation of the autophagy pathway as an alternative mechanism of protein degradation. Preclinical studies demonstrate that autophagy inhibition with hydroxychloroquine augments the antimyeloma efficacy of the proteasome inhibitor bortezomib. We conducted a phase I trial combining bortezomib and hydroxychloroquine for relapsed or refractory myeloma. We enrolled 25 patients, including 11 (44%) refractory to prior bortezomib. No protocol-defined dose-limiting toxicities occurred, and we identified a recommended phase 2 dose of hydroxychloroquine 600 mg twice daily with standard doses of bortezomib, at which we observed dose-related gastrointestinal toxicity and cytopenias. Of 22 patients evaluable for response, 3 (14%) had very good partial responses, 3 (14%) had minor responses, and 10 (45%) had a period of stable disease. Electron micrographs of bone marrow plasma cells collected at baseline, after a hydroxychloroquine run-in, and after combined therapy showed therapy-associated increases in autophagic vacuoles, consistent with the combined effects of increased trafficking of misfolded proteins to autophagic vacuoles and inhibition of their degradative capacity. Combined targeting of proteasomal and autophagic protein degradation using bortezomib and hydroxychloroquine is therefore feasible and a potentially useful strategy for improving outcomes in myeloma therapy.

Salvage therapy of multiple myeloma: the new generation drugs

During the past decade, overall results of treatment of multiple myeloma (MM) have been improved and survival curves are now significantly better with respect to those obtained with historical treatment. These improvements are linked to a deeper knowledge of the biology of disease and to the introduction in clinical practice of drugs with different mechanism of action such as proteasome inhibitors and immunomodulatory drugs (IMiDs). However, MM remains in most cases an incurable disease. For patients who relapse after treatment with novel agents, the prognosis is dismal and new drugs and therapeutic strategies are required for continued disease control. In this review, we summarize new insights in salvage therapy for relapsed/refractory MM as emerging from recent clinical trials exploring the activity of bendamustine, new generation proteasome inhibitors, novel IMiDs, monoclonal antibodies, and drugs interfering with growth pathways.

The role of epigenetics in the biology of multiple myeloma

Several recent studies have highlighted the biological complexity of multiple myeloma (MM) that arises as a result of several disrupted cancer pathways. Apart from the central role of genetic abnormalities, epigenetic aberrations have also been shown to be important players in the development of MM, and a lot of research during the past decades has focused on the ways DNA methylation, histone modifications and noncoding RNAs contribute to the pathobiology of MM. This has led to, apart from better understanding of the disease biology, the development of epigenetic drugs, such as histone deacetylase inhibitors that are already used in clinical trials in MM with promising results. This review will present the role of epigenetic abnormalities in MM and how these can affect specific pathways, and focus on the potential of novel 'epidrugs' as future treatment modalities for MM.

Pomalidomide for the treatment of relapsed-refractory multiple myeloma: a review of biological and clinical data

Despite the improvements thanks to the introduction of proteasome inhibitors and immunomodulatory drugs (IMiDs), nearly all myeloma patients eventually become refractory to these drugs. Consequently, the outcome of these patients is very poor. Pomalidomide is a new IMiD with a similar structure to the commonly used IMiD thalidomide and lenalidomide. Pomalidomide exhibited more potent anti-myeloma activity and a similar favorable safety profile compared with thalidomide and lenalidomide. In Phase I-II studies pomalidomide plus low-dose dexamethasone demonstrated activity in myeloma patients refractory to both bortezomib and IMiDs. Based on the results of a Phase III trial, the FDA and EMA agencies granted accelerated approval to pomalidomide, which is now considered a new effective strategy for relapsed and/or refractory myeloma patients. Very promising results were obtained when pomalidomide-dexamethasone was used in combination with other compounds. This review provides updated information about pharmacokinetics, mechanism of action, resistance, clinical efficacy and safety of pomalidomide.

Histone deacetylase inhibitor valproic acid affects plasmacytoid dendritic cells phenotype and function

OBJECTIVE

Plasmacytoid dendritic cells (PDC) represent a rare subset of dendritic cells specialized in the production of type I IFN in response to microbial pathogens. Recent data suggested that histone deacetylase (HDAC) inhibitors possess potent immunomodulatory properties both in vitro and in vivo. In this study, we assayed the ability of the HDAC inhibitor, valproic acid (VPA), to influence the phenotype and functional properties of human PDC isolated from peripheral blood.

METHODS AND RESULTS

We showed that VPA inhibited the production of IFN-α and the proinflammatory cytokines TNF-α and IL-6 by CpG-activated PDC. VPA also affected the phenotype of PDC by reducing the expression of costimulatory molecules induced by CpG activation. Moreover, VPA reduced the capacity of CpG-stimulated PDC to promote CD4(+) T cell proliferation and IFN-γ production, while enhancing the proportion of IL-10 positive T cells.

CONCLUSION

These results suggest that HDAC inhibition by VPA alters essential human PDC functions, highlighting the need for monitoring immune functions in cancer patients receiving HDAC inhibitors, but also making these drugs attractive therapies in inflammatory, and autoimmune diseases implicating PDC.

Efficacy of Subcutaneous Bortezomib in the Management of Patients with Multiple Myeloma or Relapsed Mantle Cell Lymphoma

The identification of the ubiquitin–proteasome system as a new therapeutic target has been one of the most recent successes in cancer treatment. The development and clinical approval of the first-in-class proteasome inhibitor, bortezomib has revolutionized the treatment of multiple myeloma (MM) and mantle cell lymphoma (MCL). In MM, bortezomib is now integrated in induction, conditioning, consolidation, maintenance, and salvage treatment protocols. Bortezomib-based regimens provide high remission rates and confer significant survival advantage compared to conventional chemotherapy in both the bone marrow transplant and non-transplant setting. In MCL, overall response rates in patients who have received at least one prior therapy range from 30 to 45%, even in chemotherapy resistant patients. Clinical trials to further improve the sequencing of bortezomib-containing combination therapies are ongoing. Until recently, intravenous injection was the standard route of bortezomib administration. However, severe adverse side effects, peripheral neuropathy in particular, were observed in up to 16% of MM patients and up to 54% of MCL patients treated with intravenous bortezomib, with grade 3 and 4 in 11 and 12% of patients, respectively. Moreover, complete remission rates, if at all, are low and duration of response is short both in MM and MCL. These limitations may be overcome by changing the method of bortezomib administration as well as by rationally combining bortezomib with other therapeutic agents. Indeed, recent data demonstrate that subcutaneous bortezomib administration is non-inferior to intravenous administration, with an improved systemic safety profile, good local tolerance, and a more convenient route of administration. Based on these data, subcutaneous bortezomib injection was approved as a supplemental new drug application for all approved indications in MM and MCL after at least one prior therapy. More than 30 clinical trials in MM and MCL are currently ongoing to evaluate the efficacy and safety profile of subcutaneous bortezomib also in induction, maintenance, and salvage therapy.

Vorinostat in combination with lenalidomide and dexamethasone in patients with relapsed or refractory multiple myeloma

The addition of vorinostat to lenalidomide/dexamethasone represents a novel combination therapy in multiple myeloma (MM), informed by laboratory studies suggesting synergy. This was a phase I, multicenter, open-label, non-randomized, dose-escalating study in patients with relapsed or relapsed and refractory MM. Clinical evaluation, electrocardiogram, laboratory studies and adverse events were obtained and assessed. The maximum-tolerated dose was not reached owing to a non-occurrence of two dose-limiting toxicities per six patients tested at any of the dosing levels. Patients tolerated the highest dose tested (Level 5) and this was considered the maximum administered dose: at 400 mg vorinostat on days 1-7 and 15-21, 25 mg lenalidomide on days 1-21 and 40 mg dexamethasone on days 1, 8, 15 and 22, per 28-day cycle. Drug-related adverse events were reported in 90% of patients serious adverse experiences were reported in 45% of the patients and 22% of all patients had adverse experiences considered, possibly related to study drug by the investigators. A confirmed partial response or better was reported for 14/30 patients (47%) evaluable for efficacy, including 31% of patients previously treated with lenalidomide. Vorinostat in combination with lenalidomide and dexamethasone proved tolerable with appropriate supportive care, with encouraging activity observed.