Search

On February 25, 2009, a panel of international experts on plasma cell dyscrasia and skeletal disease met to discuss monoclonal gammopathy of undetermined significance (MGUS). This non-malignant B-cell disorder is the most common plasma cell dyscrasia and is associated with an increased risk of developing serious B-cell disorders. Individuals with MGUS also have an increased risk of osteoporosis and osteopenia associated with an increased likelihood of developing fractures especially in the vertebral column, peripheral neuropathy and thromboembolic events. The goal of the meeting was to develop a consensus statement regarding the appropriate tests to screen, evaluate and follow-up patients with MGUS. The panel also addressed the identification and treatment of MGUS-related skeletal problems, thromboembolic events and neurological complications. The following consensus statement outlines the conclusions and marks the first time that a consensus statement for the screening and treatment of MGUS has been clearly stated. [ABSTRACT FROM AUTHOR]

Although multiple myeloma remains incurable, recent advances in research have created a new paradigm for the development of novel agents for myeloma treatment. Biological insights are being translated rapidly from bench to bedside, with an increasing number of agents available at all stages of disease. Concomitantly, the drug development and approval process has become more challenging. Defining optimal clinical dosing schedules and therapeutic regimens is increasingly dependent on insights derived from genomic, proteomic and cell signaling studies. Because the maximum tolerated dose of a novel agent may not be the same as the optimal biological dose, designing phase I trials is more complex. Evaluation of new agents in patients who have relapsed is more challenging because the number of effective therapies has increased. Finally, choosing a ‘standard therapy’ control arm for randomised trials is more difficult because of the increased number of potential comparator regimens. In June 2005, the Multiple Myeloma Research Foundation (MMRF) sponsored a roundtable symposium in Washington, DC, to define the strategies and guidelines for phases I, II and III development of new myeloma agents, with the ultimate goal of speeding delivery of new therapies to myeloma patients. [ABSTRACT FROM AUTHOR]

Multiple myeloma remains an incurable disease, and a new perspective on the approach to therapy is required. The aim of this review is to focus on a number of key areas where recent advances in the biology of the disease have not only yielded an understanding of the disease pathogenesis but have also suggested novel treatment approaches. Factors mediating myeloma cell growth, survival and the complex interaction of myeloma cells with the bone marrowmicroenvironment have provided a framework for the rational design of therapeutic agents. The development of such biologically based treatments which target both the tumour cell and the microenvironment, in order to achieve more complete and selective eradication of myeloma cells and the maintenance of minimal residual disease states, may ultimately lead to improved disease‐free survivial and potentially a cure. [ABSTRACT FROM AUTHOR]

Background: The duration of response to treatment is a major prognostic factor, and early relapse (ER) strongly predicts inferior survival in multiple myeloma (MM). However, the definitions of ER in MM vary from study to study and how to dynamically integrate risk distribution is still unsolved. Methods: This study evaluated these ER definitions and further investigated the underlying relationship with static risk distribution in 629 newly diagnosed MM (NDMM) patients from the National Longitudinal Cohort of Hematological Diseases in China (NCT04645199). Results: These data indicated that early relapse within 18 months (ER18) after initial treatment was the best time point for identifying early progression and dynamic high‐risk in MM. The ER18 population (114 of 587, 19.4%) presented with more aggressive biologic features and the inferior response to treatment compared to a reference cohort (p <.001), with a significantly short median overall survival (OS) of 28.9 months. Multivariate analyses confirmed the most significant prognostic value of ER18 on OS in the context of International Staging System stage, elevated lactate dehydrogenase, thrombocytopenia, cytogenetic abnormalities, and treatment (hazard ratio, 4.467; p <.001). The authors also described the specific transitions from static risk profile to dynamic risk distribution and then constructed a mixed‐risk‐pattern to identify four novel populations with distinct survival (p <.001). Additionally, the authors proposed a second‐state model that predicts dynamic risk changes, enabling a complementary role to the Revised International Staging System model in facilitating individualized systematic treatment. Conclusions: Collectively, this study concludes that ER18 is a simple and dynamic prognostic predictor in MM. In addition to static risk assessment, dynamic risk plays an important role in survival prediction. The present study sheds light on the optimal time point for early relapse (ER), defined as relapse within 18 months after initial treatment, and highlights its significant dynamic predictive impact on the prognosis in multiple myeloma. Alongside the conventional static risk stratification at diagnosis, a second‐state model that incorporates ER reveals dynamic risk changes that facilitate individualized systematic treatment. [ABSTRACT FROM AUTHOR]

The treatment of multiple myeloma (MM) has gone through several major advances over the last 5 years with the introduction of next generation proteasome inhibitors (PI; carfilzomib, ixazomib) and immunomodulatory derivatives (IMiD; pomalidomide), with these new agents having a substantial impact on patient outcome. However, despite these advances, MM remains a highly resistant disease given its propensity for clonal heterogeneity and its complex interaction with the surrounding bone marrow microenvironment. Almost all patients eventually relapse despite therapeutic responses to a PI, IMiD or both. With the regulatory approval of the monoclonal antibodies Daratumumab and Elotuzumab in 2015, impressive and durable responses are being observed, even in heavily pre-treated patients who have exhausted other therapeutic options, suggesting immunological approaches in this setting have real merit. This review will focus on newer monoclonal antibodies and chimericantigen receptor (CAR) T cell strategies currently under investigation and in various stages of clinical development. [ABSTRACT FROM AUTHOR]

Focuses on the methods to treat multiple myeloma (MM). Number of patients affected by MM in the U.S. in 2002; Characteristics of MM.

Background: Multiple myeloma (MM) is an incurable hematologic malignancy requiring long‐term, continuous therapy. Despite its chronic and unrelenting course, studies examining quality of life (QOL), psychological distress, and perceptions of prognosis by line of therapy are lacking. Methods: The authors conducted a cross‐sectional, multisite study of patients undergoing treatment for MM (excluding maintenance) between June 2020 and January 2021. The authors conducted purposeful sampling and recruited patients to 3 cohorts based on lines of therapy: 1) newly diagnosed receiving first‐line therapy; 2) 2 to 3 lines; and 3) 4 or more lines. Patients completed validated questionnaires to assess their QOL, fatigue, psychological distress, and perceptions of prognosis. Results: A total of 180 patients with MM were enrolled (newly diagnosed [n = 60], 2 to 3 lines [n = 60], and ≥4 lines of therapy [n = 60]). QOL, symptom burden, and fatigue scores did not differ by lines of therapy. There were no statistically significant differences in psychological distress by line of therapy. The rates of clinically significant depression, anxiety, and post‐traumatic stress disorder symptoms were 23.9% (43 of 180), 23.9% (43 of 180), and 24.4% (44 of 180), respectively. Most patients (84.7%, 149 of 176) reported that their oncologist told them their cancer was incurable, but only 30.6% (53 of 173) acknowledged that they were terminally ill, and 42.0% (73 of 174) reported that they thought their cancer was incurable. Conclusions: Patients with MM undergoing treatment experience impaired QOL and elevated psychological distress across the disease continuum, regardless of line of therapy. A substantial proportion of patients with MM have significant misperceptions about their prognosis and the curability of their illness despite reporting being informed of the prognosis by their oncologist. Lay Summary: This study discusses 180 patients with MM (newly diagnosed [n = 60], 2‐3 lines [n = 60], and ≥4 lines of therapy [n = 60]). Quality of life, symptom burden, and fatigue scores do not differ by lines of therapy. There are also no statistically significant differences in psychological distress by line of therapy.The rates of clinically significant depression, anxiety, and post‐traumatic stress disorder symptoms are 23.9%, 23.9%, and 24.4%, respectively.Most patients (84.7%) report that their oncologist told them their cancer was incurable, but only 30.6% acknowledge that they are terminally ill, and 42.0% report that they thought their cancer was incurable. Patients with multiple myeloma undergoing treatment experience impaired quality of life and elevated psychological distress across the disease continuum. Although the majority reported that their oncologist had told them that their cancer is incurable, a substantial proportion still reported that they believed their cancer was curable. [ABSTRACT FROM AUTHOR]

Summary: In this review, two types of soft‐tissue involvement in multiple myeloma are defined: (i) extramedullary (EMD) with haematogenous spread involving only soft tissues and (ii) paraskeletal (PS) with tumour masses arising from skeletal lesions. The incidence of EMD and PS plasmacytomas at diagnosis ranges from 1·7% to 4·5% and 7% to 34·4% respectively. EMD disease is often associated with high‐risk cytogenetics, resistance to therapy and worse prognosis than in PS involvement. In patients with PS involvement a proteasome inhibitor‐based regimen may be the best option followed by autologous stem cell transplantation (ASCT) in transplant eligible patients. In patients with EMD disease who are not eligible for ASCT, a proteasome inhibitor‐based regimen such as lenalidomide‐bortezomib‐dexamethasone (RVD) may be the best option, while for those eligible for high‐dose therapy a myeloma/lymphoma‐like regimen such as bortezomib, thalidomide and dexamethasone (VTD)‐RVD/cisplatin, doxorubicin, cyclophosphamide and etoposide (PACE) followed by SCT should be considered. In both EMD and PS disease at relapse many strategies have been tried, but this remains a high‐unmet need population. [ABSTRACT FROM AUTHOR]

Summary The development of an immunotherapeutic strategy targeting CD138 antigen could potentially represent a new treatment option for multiple myeloma (MM). This study evaluated the immune function of CD138 peptide-specific cytotoxic T lymphocytes (CTL), generated ex vivo using an HLA-A2-specific CD138 epitope against MM cells. A novel immunogenic HLA-A2-specific CD138260-268 (GLVGLIFAV) peptide was identified from the full-length protein sequence of the CD138 antigen, which induced CTL specific to primary CD138+ MM cells. The peptide-induced CD138-CTL contained a high percentage of CD8+ activated/memory T cells with a low percentage of CD4+ T cell and naive CD8+ T cell subsets. The CTL displayed HLA-A2-restricted and CD138 antigen-specific cytotoxicity against MM cell lines. In addition, CD138-CTL demonstrated increased degranulation, proliferation and γ-interferon secretion to HLA-A2+/CD138+ myeloma cells, but not HLA-A2−/CD138+ or HLA-A2+/CD138− cells. The immune functional properties of the CD138-CTL were also demonstrated using primary HLA-A2+/CD138+ cells isolated from myeloma patients. In conclusion, a novel immunogenic CD138260-268 (GLVGLIFAV) peptide can induce antigen-specific CTL, which might be useful for the treatment of MM patients with peptide-based vaccine or cellular immunotherapy strategies. [ABSTRACT FROM AUTHOR]

Encouraging progress has been made in the treatment of patients with relapsed/refractory multiple myeloma (MM). The rapidly evolving understanding of key pathways responsible for tumor growth and survival has led to the development of novel agents (including immunomodulatory drugs, proteasome inhibitors, histone deacetylase inhibitors, and other targeted agents) with the potential to provide significant improvements in response and survival, and influence treatment guidelines. This review summarizes recent advances in understanding of the biology of relapsed/refractory MM and clinical trials with novel targeted agents that are currently under investigation for patients with this disease. [ABSTRACT FROM AUTHOR]

Summary: Multiple myeloma (MM) affects 15 000 new patients annually in the US, with 50 000 total patients, and remains incurable. Our preliminary in vitro and animal studies suggest a role for MM–host interactions in regulating MM cell growth, drug resistance, and migration in the bone marrow. Importantly, treatment strategies which target mechanisms whereby MM cells grow and survive in the bone marrow, including thalidomide and its potent immunomodulatory derivatives and proteasome inhibitor PS-341, can overcome classical drug resistance in preclinical and early clinical studies. [ABSTRACT FROM AUTHOR]

Investigates novel therapies for multiple myeloma (MM). Role of the bone marrow microenvironment in the pathogenesis of MM; Thalidomide and its immunomodulatory derivatives; Proteasome inhibitors; NF-kappabetta inhibitors; Arsenic trioxide; 2-methyloxyestradiol; PTK787 tyrosine kinase inhibitor.

Summary: Smouldering multiple myeloma (SMM) is associated with increased risk of progression to multiple myeloma within 2 years, with no approved treatments. Elotuzumab has been shown to promote natural killer (NK) cell stimulation and antibody‐dependent cellular cytotoxicity (ADCC) in vitro. CD56dim (CD56dim/CD16+/CD3−/CD45+) NK cells represent the primary subset responsible for elotuzumab‐induced ADCC. In this phase II, non‐randomized study (NCT01441973), patients with SMM received elotuzumab 20 mg/kg intravenously (cycle 1: days 1, 8; monthly thereafter) or 10 mg/kg (cycles 1, 2: weekly; every 2 weeks thereafter). The primary endpoint was the relationship between baseline proportion of bone marrow‐derived CD56dim NK cells and maximal M protein reduction; secondary endpoints included overall response rate (ORR) and progression‐free survival (PFS). Fifteen patients received 20 mg/kg and 16 received 10 mg/kg; combined data arepresented. At database lock (DBL, September 2014), no association was found between baseline CD56dim NK cell proportion and maximal M protein reduction. With minimum 28 months' follow‐up (DBL: January 2016), ORR (90% CI) was 10% (2·7–23·2) and 2‐year PFS rate was 69% (52–81%). Upper respiratory tract infections occurred in 18/31 (58%) patients. Four (13%) patients experienced infusion reactions, all grade 1–2. Elotuzumab plus lenalidomide/dexamethasone is under investigation for SMM. [ABSTRACT FROM AUTHOR]

Abstract: We sought a regimen that incorporates optimal novel agents and balances efficacy with toxicity in transplant‐ineligible multiple myeloma (MM) patients. Our study evaluated modified lenalidomide‐bortezomib‐dexamethasone (RVD lite) in this population and was administered over a 35‐day cycle. Lenalidomide 15 mg was given orally on days 1–21; bortezomib 1·3 mg/m2 weekly subcutaneously on days 1, 8, 15 and 22; and dexamethasone 20 mg orally was given on the day of and day after bortezomib for 9 cycles followed by 6 cycles of consolidation with lenalidomide and bortezomib. The primary objective was to evaluate the overall response rate (ORR); secondary objectives included safety, progression‐free survival (PFS) and overall survival (OS). Fifty‐three eligible patients were screened between April 2013 and May 2015; 50 received at least one dose of therapy. Median age at study entry was 73 years (range 65–91). The ORR was 86% and 66% of patients achieved a very good partial response or better. Median PFS was 35·1 months (95% confidence interval 30·9–not reached) and median OS was not reached at a median follow‐up of 30 months. Peripheral neuropathy was reported in 31 (62%) patients with only 1 patient experiencing grade 3 symptoms. RVD lite is a well‐tolerated and highly effective regimen, with robust PFS and OS, in the transplant‐ineligible MM population. [ABSTRACT FROM AUTHOR]

Multiple myeloma (MM), a B cell malignancy characterized by clonal proliferation of plasma cells in the bone marrow, remains incurable despite the use of novel and conventional therapies. In this study, we demonstrated MM cell cytotoxicity triggered by realgar (REA; As4S4) nanoparticles (NREA) versus Arsenic trioxide (ATO) against MM cell lines and patient cells. Both NREA and ATO showed in vivo anti-MM activity, resulting in significantly decreased tumour burden. The anti-MM activity of NREA and ATO is associated with apoptosis, evidenced by DNA fragmentation, depletion of mitochondrial membrane potential, cleavage of caspases and antiapoptotic proteins. NREA induced 2G/M cell cycle arrest and modulation of cyclin B1, p53 (TP53), p21 (CDKN1A), Puma (BBC3) and Wee-1 (WEE1). Moreover, NREA induced modulation of key regulatory molecules in MM pathogenesis including JNK activation, c-Myc (MYC), BRD4, and histones. Importantly, NREA, but not ATO, significantly depleted the proportion and clonogenicity of the MM stem-like side population, even in the context of the bone marrow stromal cells. Finally, our study showed that both NREA and ATO triggered synergistic anti-MM activity when combined with lenalidomide or melphalan. Taken together, the anti-MM activity of NREA was more potent compared to ATO, providing the preclinical framework for clinical trials to improve patient outcome in MM. [ABSTRACT FROM AUTHOR]

Multiple myeloma ( MM) is a lethal haematological malignancy that arises in the context of a tumour microenvironment that promotes resistance to apoptosis and immune escape. In the present study, we demonstrate that co-culture of MM cells with stromal cells results in increased resistance to cytotoxic and biological agents as manifested by decreased rates of cell death following exposure to alkylating agents and the proteosome inhibitor, bortezomib. To identify the mechanism of increased resistance, we examined the effect of the co-culture of MM cells with stroma cells, on expression of the MUC1 oncogene, known to confer tumour cells with resistance to apoptosis and necrosis. Co-culture of stroma with MM cells resulted in increased MUC1 expression by tumour cells. The effect of stromal cell co-culture on MUC1 expression was not dependent on cell contact and was therefore thought to be due to soluble factors secreted by the stromal cells into the microenvironment. We demonstrated that MUC1 expression was mediated by interleukin-6 and subsequent up-regulation of the JAK- STAT pathway. Interestingly, the effect of stromal cell co-culture on tumour resistance was partially reversed by silencing of MUC1 in MM cells, consistent with the potential role of MUC1 in mediating resistance to cytotoxic-based therapies. [ABSTRACT FROM AUTHOR]

Proteasome inhibitors ( PIs) are highly active in multiple myeloma ( MM) but resistance is commonly observed. All clinical stage PIs effectively inhibit chymotrypsin-like ( CT-L) activity; one possible mechanism of resistance is compensatory hyperactivation of caspase-like (C-L) and trypsin-like (T-L) subunits, in response to CT-L blockade. Marizomib ( MRZ), an irreversible PI that potently inhibits all three 20S proteasome subunits with a specificity distinct from other PIs, is currently in development for treatment of MM and malignant glioma. The pan-proteasome pharmacodynamic activity in packed whole blood and peripheral blood mononuclear cells was measured in two studies in patients with advanced solid tumours and haematological malignancies. Functional inhibition of all proteasome subunits was achieved with once- or twice-weekly MRZ dosing; 100% inhibition of CT-L was frequently achieved within one cycle at therapeutic doses. Concomitantly, C-L and T-L activities were either unaffected or increased, suggesting compensatory hyperactivation of these subunits. Importantly, this response was overcome by continued administration of MRZ, with robust inhibition of T-L and C-L (up to 80% and 50%, respectively) by the end of Cycle 2 and maintained thereafter. This enhanced proteasome inhibition was independent of tumour type and may underlie the clinical activity of MRZ in patients resistant to other PIs. [ABSTRACT FROM AUTHOR]

Our prior study utilized both in vitro and in vivo multiple myeloma ( MM) xenograft models to show that a novel alkylator melphalan-flufenamide (Melflufen) is a more potent anti- MM agent than melphalan and overcomes conventional drug resistance. Here we examined whether this potent anti- MM activity of melflufen versus melphalan is due to their differential effect on DNA damage and repair signalling pathways via γ-H2 AX/ ATR/ CHK1/Ku80. Melflufen-induced apoptosis was associated with dose- and time-dependent rapid phosphorylation of γ-H2 AX. Melflufen induces γ-H2 AX, ATR, and CHK1 as early as after 2 h exposure in both melphalan-sensitive and -resistant cells. However, melphalan induces γ-H2 AX in melphalan-sensitive cells at 6 h and 24 h; no γ-H2 AX induction was observed in melphalan-resistant cells even after 24 h exposure. Similar kinetics was observed for ATR and CHK1 in meflufen- versus melphalan-treated cells. DNA repair is linked to melphalan-resistance; and importantly, we found that melphalan, but not melflufen, upregulates Ku80 that repairs DNA double-strand breaks. Washout experiments showed that a brief (2 h) exposure of MM cells to melflufen is sufficient to initiate an irreversible DNA damage and cytotoxicity. Our data therefore suggest that melflufen triggers a rapid, robust, and an irreversible DNA damage which may account for its ability to overcome melphalan-resistance in MM cells. [ABSTRACT FROM AUTHOR]

Myeloma bone disease ( MBD) is a major cause of morbidity in multiple myeloma ( MM). We investigated bone turnover markers (BTM) as relapse predictors and biomarkers for monitoring MBD. We measured C-terminal telopeptide of type I collagen ( CTX-1), and Procollagen type 1 N Propeptide (P1 NP) in 86 MM patients and 26 controls. CTX-1 was higher in newly diagnosed patients compared to control, remission and relapse ( P < 0·05), and decreased following treatment. In the setting of relapse, a CTX-1 rise greater than the calculated least significant change ( LSC) was observed in 26% of patients 3-6 months prior to relapse ( P = 0·007), and in 60·8% up to 3 months before relapse ( P = 0·015). Statistically significant changes in CTX-1 levels were also observed in patients who were with and without bisphosphonate therapy at the time of relapse. In patients with normal renal function, mean CTX-1 level was highest in the newly diagnosed group (0·771 ± 0·400 μg/l), and lowest in the remission group (0·099 ± 0·070 μg/l) ( P < 0·0001). P1 NP levels were not statistically different across the patient groups. We conclude that CTX-1, measured on an automated hospital laboratory platform, has a role in routine treatment monitoring and predicting relapse of MBD, even in patients on bisphosphonates. [ABSTRACT FROM AUTHOR]

The proteasome inhibitor bortezomib is an effective therapy for the treatment of relapsed and refractory multiple myeloma (RRMM); however, prolonged treatment can be associated with toxicity, peripheral neuropathy and drug resistance. Our earlier studies showed that the novel proteasome inhibitor marizomib is distinct from bortezomib in its chemical structure, mechanisms of action and effects on proteasomal activities, and that it can overcome bortezomib resistance. Pomalidomide, like lenalidomide, has potent immunomodulatory activity and has been approved by the US Food and Drug Administration for the treatment of RRMM. Here, we demonstrate that combining low concentrations of marizomib with pomalidomide induces synergistic anti-MM activity. Marizomib plus pomalidomide-induced apoptosis is associated with: (i) activation of caspase-8, caspase-9, caspase-3 and PARP cleavage, (ii) downregulation of cereblon (CRBN), IRF4, MYC and MCL1, and (iii) suppression of chymotrypsin-like, caspaselike, and trypsin-like proteasome activities. CRBN-siRNA attenuates marizomib plus pomalidomide-induced MM cells death. Furthermore, marizomib plus pomalidomide inhibits the migration of MM cells and tumour-associated angiogenesis, as well as overcomes cytoprotective effects of bone marrow microenvironment. In human MM xenograft model studies, the combination of marizomib and pomalidomide is well tolerated, inhibits tumour growth and prolongs survival. These preclinical studies provide the rationale for on-going clinical trials of combined marizomib and pomalidomide to improve outcome in patients with RRMM. [ABSTRACT FROM AUTHOR]

Proteasome inhibitors ( PI) and immunomodulatory agents ( IMIDs) have improved the overall survival (OS) of patients with multiple myeloma ( MM), but concerns have been raised about increased incidence of extramedullary disease ( EMD) after the combined use of PIs and IMIDs for upfront therapy. We evaluated whether the addition of lenalidomide to bortezomib-based front-line regimens precipitated earlier development of EMD. We reviewed the charts of 117 MM patients (median follow-up from diagnosis 6·1 years; range 0·1-10·2 years) enrolled in eight clinical trials of first-line treatment with bortezomib-based regimens, with or without lenalidomide. We assessed development of EMD as extraosseous (distant from bone) or osseous (originating from bone) plasmacytomas. The primary endpoint was time from diagnosis until development of EMD, based on imaging, biopsy and/or physical examination. Any form of EMD at progression was observed in 40 (34·2%) patients, including 21 (18%) osseous, 8 (7%) extraosseous and 11 (9%) both osseous and extraosseous. Median OS was 0·9 years (range 0·1-4·8 years) after extraosseous EMD development. Sensitivity analyses with follow-up times truncated at 5 years detected no statistically significant difference in rates of any EMD form between the two groups ( P > 0·2 for each comparison). Therefore, we observed no evidence that bortezomib-lenalidomide-based front-line therapy precipitates earlier EMD. [ABSTRACT FROM AUTHOR]

Extramedullary disease ( EMD), defined as an infiltrate of clonal plasma cells at an anatomic site distant from the bone marrow, is an uncommon manifestation of multiple myeloma. Six hundred and sixty-three consecutive patients with multiple myeloma who underwent stem cell transplantation between January 2005 and December 2011 were assessed for the presence of EMD. A cohort of 55 patients with biopsy-proven EMD was identified, comprising 8·3% of the total study population. EMD was present at the time of diagnosis in 14·5% of cases and at the time of relapse in 76% of patients. The most common EMD presentations at relapse were liver involvement and pleural effusions. EMD specimens had high expression of CD44 (92%) and moderate expression of CXCR4. The median overall survival from time of myeloma diagnosis was 4·1 years (95% CI: 3·1, 5·1) and the median overall survival from time of EMD diagnosis was 1·3 years (95% CI: 0·8, 2·3). This report demonstrates that the incidence of EMD has not increased with the introduction of novel agents and stem cell transplantation. The most common EMD presentations in the relapsed setting were liver and pleural fluid. The presence of CD44 and CXCR4 expression may represent new markers of EMD that warrant further investigation. [ABSTRACT FROM AUTHOR]

Multiple myeloma (MM) is characterized by clonal expansion of malignant plasma cells in the bone marrow (BM). Despite the significant advances in treatment, MM is still a fatal malignancy. This is mainly due to the supportive role of the BM microenvironment in differentiation, migration, proliferation, survival, and drug resistance of the malignant plasma cells. The BM microenvironment is composed of a cellular compartment (stromal cells, osteoblasts, osteoclasts, endothelial cells, and immune cells) and a non-cellular compartment. In this review, we discuss the interaction between the malignant plasma cell and the BM microenvironment and the strategy to target them. [ABSTRACT FROM AUTHOR]

Everolimus, an oral mammalian target of rapamycin ( mTOR) inhibitor, has been studied in multiple myeloma (MM) but lacks significant single agent activity. Based on preclinical studies showing synergistic activity of mTOR inhibitors with lenalidomide, we studied the combination of lenalidomide and everolimus in relapsed or refractory MM in a phase I clinical trial. We assessed patient samples using gene expression, Western blotting and immunohistochemistry to probe the mTOR pathway. Twenty-six patients were evaluable for toxicity. Dose-limiting toxicities included grade 4 neutropenia and thrombocytopenia. The maximum tolerated dose was lenalidomide 15 mg and everolimus 5 mg for 21 d with a 7 d rest period. Grade 3/4 adverse events included thrombocytopenia (35%) and neutropenia (42%). The overall response rate was 65% (1 complete response + 4 partial response + 10 minimal response). The median progression-free survival was 5·5 months and median overall survival was 29·5 months. Biomarker data demonstrated downregulation of phosphorylated p70S6K. Gene expression profiling suggested activation of mTOR in responders versus non-responders. The combination of lenalidomide and everolimus was well tolerated with predictable toxicities and showed responses in a heavily pretreated population. When confirmed with larger patient numbers, this analysis may guide patient selection for future clinical trials of mTOR inhibition in MM. [ABSTRACT FROM AUTHOR]

Despite the recent development of effective therapeutic agents against multiple myeloma ( MM), new therapeutic approaches, including immunotherapies, remain to be developed. Here we identified novel human leucocyte antigen ( HLA)-A*0201 ( HLA-A2)-restricted cytotoxic T lymphocyte ( CTL) epitopes from a B cell specific molecule HLA-DOβ ( DOB) as a potential target for MM. By DNA microarray analysis, the HLA- DOB expression in MM cells was significantly higher than that in normal plasma cells. Twenty-five peptides were predicted to bind to HLA-A2 from the amino acid sequence of HLA- DOB. When screened for the immunogenicity in HLA-A2-transgenic mice immunized with HLA- DOB c DNA, 4 peptides were substantially immunogenic. By mass spectrometry analysis of peptides eluted from HLA-A2-immunoprecipitates of MM cell lines, only two epitopes, HLA- DOB232-240 ( FLLGLIFLL) and HLA- DOB185-193 ( VMLEMTPEL), were confirmed for their physical presence on cell surface. When healthy donor blood was repeatedly stimulated in vitro with these two peptides and assessed by antigen-specific γ-interferon secretion, HLA- DOB232-240 was more immunogenic than HLA- DOB185-193. Additionally, the HLA- DOB232-240-specific CTLs, but not the HLA- DOB185-193-specific CTLs, displayed an major histocompatibility complex class I-restricted reactivity against MM cell lines expressing both HLA-A2 and HLA- DOB. Taken together, based on the physical presence on tumour cell surface and high immunogenicity, HLA- DOB232-240 might be useful for developing a novel immunotherapy against MM. [ABSTRACT FROM AUTHOR]

Multiple myeloma ( MM) is an incurable neoplasm caused by proliferation of malignant plasma cells in the bone marrow ( BM). MM is characterized frequently by a complete or partial deletion of chromosome 13q14, seen in more than 50% of patients at diagnosis. Within this deleted region the tripartite motif containing 13 ( TRIM13, also termed RFP2) gene product has been proposed to be a tumour suppressor gene ( TSG). Here, we show that low expression levels of TRIM13 in MM are associated with chromosome 13q deletion and poor clinical outcome. We present a functional analysis of TRIM13 using a loss-of-function approach, and demonstrate that TRIM13 downregulation decreases tumour cell survival as well as cell cycle progression and proliferation of MM cells. In addition, we provide evidence for the involvement of TRIM13 downregulation in inhibiting the NF kappa B pathway and the activity of the 20 S proteasome. Although this data does not support a role of TRIM13 as a TSG, it substantiates important roles of TRIM13 in MM tumour survival and proliferation, underscoring its potential role as a novel target for therapeutic intervention. [ABSTRACT FROM AUTHOR]

In this prospective study of patients with relapsed or relapsed and refractory multiple myeloma ( MM) treated with lenalidomide and dexamethasone, relationships between markers of endothelial stress and drug administration and incidence of venous thromboembolism ( VTE) were assessed. Of 33 enrolled patients, laboratory and treatment data were available for 32 patients. Of these, 23 received pulsed dexamethasone (40 mg/day on days 1-4, 9-12 and 17-21 of each 28-day cycle) and 9 received weekly dexamethasone (40 mg/day on days 1, 8, 15 and 21 of each cycle). The overall incidence of VTE was 9%. A decreasing trend in markers values was observed with intercellular adhesion molecule ( P = 0·05), fibrinogen ( P = 0·008), plasminogen activator inhibitor-1 ( P < 0·001), homocysteine ( P = 0·002) and P-selectin ( P < 0·001) during therapy. Compared with weekly dexamethasone, pulsed dexamethasone was associated with significantly greater variation in mean adjusted relative values of fibrinogen, P-selectin and vascular endothelial growth factor ( P < 0·001 for all comparisons), although there was no apparent association with VTE incidence. Lenalidomide plus dexamethasone affects endothelial stress marker levels in patients with advanced MM. The higher variation seen with pulsed dexamethasone suggests greater endothelial stress with this approach. [ABSTRACT FROM AUTHOR]

This report represents a further update of the consensus panel criteria for the assessment of clinical response in patients with Waldenström macroglobulinaemia ( WM). These criteria have been updated in light of further data demonstrating an improvement in categorical responses with new drug regimens as well as acknowledgement of the fact that such responses are predictive of overall outcome. A number of key changes are proposed but challenges do however remain and these include the variability in kinetics of immunoglobulin M ( IgM) reduction with different treatment modalities and the apparent discrepancy between IgM and bone marrow/tissue response noted with some regimens. Planned sequential bone marrow assessments are encouraged in clinical trials. [ABSTRACT FROM AUTHOR]

Jasmonates, plant stress hormones, have been demonstrated to be effective in killing various types of cancer cells. We therefore tested if methyljasmonate ( MJ) has activity against multiple myeloma ( MM) in vitro and in vivo. MM cell lines and primary MM tumour cells responded to MJ in vitro at concentrations that did not significantly affect normal haematopoietic cells, without stroma-mediated resistance. Brief MJ exposures of MM cells caused release of Hexokinase 2 ( HK2) from mitochondria, rapid ATP depletion, perturbation of major intracellular signalling pathways, and ensuing mainly apoptotic cell death. Sensitivity to MJ correlated with lower cellular glucose consumption and lactate production, as well as lower intracellular protein levels of HK2, phosphorylated Voltage-dependent anion channel 2/3 (p VDAC2/3) and Aldo-keto reductase family 1 member C1 ( AKR1 C1), which represent potential biomarkers of responsiveness to MJ treatment, especially as AKR1 C1 transcript levels also correlate with clinical outcome in bortezomib- or dexamethasone-treated MM patients. Interestingly, MJ synergized with bortezomib in vitro and prolonged survival of immunocompromised mice harbouring diffuse lesions of MM.1 S cells compared to vehicle-treated mice ( P = 0·0046). These studies indicate that jasmonates represent a new, promising strategy to treat MM. [ABSTRACT FROM AUTHOR]

The combination of lenalidomide-dexamethasone is active in multiple myeloma ( MM). Preclinical data showed that the Akt inhibitor, perifosine, sensitized MM cells to lenalidomide and dexamethasone, providing the rationale for this Phase I, multicentre, single-arm study to assess the safety and determine the maximum-tolerated dose ( MTD) of perifosine-lenalidomide-dexamethasone in relapsed and relapsed/refractory MM. Patients received escalating doses of perifosine 50-100 mg daily and lenalidomide 15-25 mg once daily on days 1-21 of each 28-d cycle, plus dexamethasone 20-40 mg weekly thereafter, as indicated. Thirty-two patients were enrolled across four dose cohorts. MTD was not reached, with 31 patients evaluable for safety/tolerability. The most common all-causality grade 1-2 adverse events were fatigue (48%) and diarrhoea (45%), and grade 3-4 neutropenia (26%), hypophosphataemia (23%), thrombocytopenia (16%), and leucopenia (13%). Among 30 evaluable patients, 73% (95% confidence interval, 57·5-89·2%) achieved a minimal response or better, including 50% with a partial response or better. Median progression-free survival was 10·8 months and median overall survival 30·6 months. Response was associated with phospho-Akt in pharmacodynamic studies. Perifosine-lenalidomide-dexamethasone was well tolerated and demonstrated encouraging clinical activity in relapsed and relapsed/refractory MM. [ABSTRACT FROM AUTHOR]

Multiple Myeloma ( MM), a malignancy of plasma cells, remains incurable despite the use of conventional and novel therapies. Halofuginone ( HF), a synthetic derivative of quinazolinone alkaloid, has recently been shown to have anti-cancer activity in various preclinical settings. This study demonstrated the anti-tumour activity of HF against a panel of human MM cell lines and primary patient-derived MM cells, regardless of their sensitivity to conventional therapy or novel agents. HF showed anti- MM activity in vivo using a myeloma xenograft mouse model. HF suppressed proliferation of myeloma cells alone and when co-cultured with bone marrow stromal cells. Similarly, HF induced apoptosis in MM cells even in the presence of insulin-like growth factor 1 or interleukin 6. Importantly, HF, even at high doses, did not induce cytotoxicity against CD40 activated peripheral blood mononuclear cells from normal donors. HF treatment induced accumulation of cells in the G0/ G1 cell cycle and induction of apoptotic cell death associated with depletion of mitochondrial membrane potential; cleavage of poly ( ADP-ribose) polymerase and caspases-3, 8 and 9 as well as down-regulation of anti-apoptotic proteins including Mcl-1 and X- IAP. Multiplex analysis of phosphorylation of diverse components of signalling cascades revealed that HF induced changes in P38 MAPK activation; increased phosphorylation of c-jun, c-jun NH(2)-terminal kinase ( JNK), p53 and Hsp-27. Importantly, HF triggered synergistic cytotoxicity in combination with lenalidomide, melphalan, dexamethasone, and doxorubicin. Taken together, these preclinical studies provide the preclinical framework for future clinical studies of HF in MM. [ABSTRACT FROM AUTHOR]

The CS1 antigen provides a unique target for the development of an immunotherapeutic strategy to treat patients with multiple myeloma ( MM). This study aimed to identify HLA- A2+ immunogenic peptides from the CS1 antigen, which induce peptide-specific cytotoxic T lymphocytes ( CTL) against HLA- A2+ MM cells. We identified a novel immunogenic HLA- A2-specific CS1239-247 ( SLFVLGLFL) peptide, which induced CS1-specific CTL ( CS1- CTL) to MM cells. The CS1- CTL showed a distinct phenotype, with an increased percentage of effector memory and activated CTL and a decreased percentage of naïve CTL. CS1239-247 peptide-specific CD8+ T cells were detected by Dimer X analyses and demonstrated functional activities specific to the peptide. The CTL displayed HLA-A2-restricted and antigen-specific cytotoxicity, proliferation, degranulation and γ-interferon ( IFN-γ) production against both primary MM cells and MM cell lines. In addition, the effector memory cells subset ( CD45 RO+ CCR7−/ CD3+ CD8+) within CS1- CTL showed a higher level of CD107a degranulation and IFN-γ production as compared to effector cells ( CD45 RO− CCR7−/ CD3+ CD8+) against HLA- A2+ primary MM cells or MM cell lines. In conclusion, this study introduced a novel immunogenic HLA- A2-specific CS1239-247 peptide capable of inducing antigen-specific CTL against MM cells that will provide a framework for its application as a novel MM immunotherapy. [ABSTRACT FROM AUTHOR]

We present the case of a woman with relapsed multiple myeloma (MM) who received combination lenalidomide and bortezomib therapy for 90 cycles followed by continuous lenalidomide monotherapy and has completed over 100 cycles of treatment to date. The patient was diagnosed with advanced-stage, symptomatic MM in 2001. Following a partial response (PR) to dexamethasone in combination with pamidronate and thalidomide, the patient underwent protocol-directed non-myeloablative allogeneic bone marrow transplantation from her matched sibling donor the following year. In 2004, the patient relapsed and was enrolled in a phase I, dose-escalation trial of lenalidomide plus bortezomib for relapsed and refractory MM. After eight cycles of study treatment, the patient achieved a minimal response. The patient received a total of 90 cycles of treatment with lenalidomide 5 mg given for 14 d every 21 d, and 1 mg/m2 of bortezomib initially given on days 1, 4, 8, and 11 for the first 20 cycles, and then weekly thereafter on days 1 and 8. Bortezomib was discontinued after 90 cycles, and the patient continued to receive lenalidomide monotherapy. As of cycle 100, the patient achieved a PR. Currently, she is clinically stable with response sustained for over 7 yrs. Therapy has been well tolerated with no significant long-term toxicity; no dose reductions of lenalidomide and bortezomib were required. The excellent tolerability of this steroid-free approach and the durable response seen underscore the potential benefits of participating in early-phase clinical trials evaluating novel therapies and new drug combinations. This case further supports that combination treatment with lenalidomide and bortezomib is an effective therapy in the management of patients with relapsed and refractory MM. [ABSTRACT FROM AUTHOR]

Osteolytic bone disease is a hallmark of symptomatic multiple myeloma. Bisphosphonates have been the mainstay of treatment to preserve skeletal integrity and prevent skeletal-related events in patients with myeloma-related bone disease. Recently, the MRC Myeloma IX trial demonstrated for the first time improved survival and delayed disease progression with the use of an intravenous amino-bisphosphonate, zoledronic acid, vs. an oral agent, clodronate, with intensive and non-intensive anti-myeloma treatment regimens in patients with newly diagnosed multiple myeloma. These results validate a large body of preclinical, translational and other clinical data suggesting anti-myeloma effects of amino-bisphosphonates. In addition, this trial also provided the first head-to-head evidence for superiority of one bisphosphonate over another (zoledronic acid vs. clodronate) for reducing skeletal morbidity in patients with multiple myeloma, as well as a prospective comparison of toxicities. Despite the use of non-bortezomib containing anti-myeloma treatment regimens in the MRC Myeloma IX trial, these results are encouraging and provide an impetus to continue to evaluate current treatment guidelines for myeloma-associated bone disease. [ABSTRACT FROM AUTHOR]

Summary SIRT1 belongs to the silent information regulator 2 (Sir2) protein family of enzymes and functions as a NAD+-dependent class III histone deacetylase. Here, we examined the anti-multiple myeloma (MM) activity of a novel oral agent, SRT1720, which targets SIRT1. Treatment of MM cells with SRT1720 inhibited growth and induced apoptosis in MM cells resistant to conventional and bortezomib therapies without significantly affecting the viability of normal cells. Mechanistic studies showed that anti-MM activity of SRT1720 is associated with: (i) activation of caspase-8, caspase-9, caspase-3, poly(ADP) ribose polymerase; (ii) increase in reactive oxygen species; (iii) induction of phosphorylated ataxia telangiectasia mutated/checkpoint kinase 2 signalling; (iv) decrease in vascular endothelial growth factor-induced migration of MM cells and associated angiogenesis; and (v) inhibition of nuclear factor-κB. Blockade of ATM attenuated SRT1720-induced MM cell death. In animal tumour model studies, SRT1720 inhibited MM tumour growth. Finally, SRT1720 enhanced the cytotoxic activity of bortezomib or dexamethasone. Our preclinical studies provide the rationale for novel therapeutics targeting SIRT1 in MM. [ABSTRACT FROM AUTHOR]

Summary Recent advances regarding the introduction of anti-adhesion strategies as a novel therapeutic concept in oncology hold great promise. Here we evaluated the therapeutic potential of the new-in-class-molecule selective-adhesion-molecule (SAM) inhibitor Natalizumab, a recombinant humanized IgG4 monoclonal antibody, which binds integrin-α4, in multiple myeloma (MM). Natalizumab, but not a control antibody, inhibited adhesion of MM cells to non-cellular and cellular components of the microenvironment as well as disrupted the binding of already adherent MM cells. Consequently, Natalizumab blocked both the proliferative effect of MM-bone marrow (BM) stromal cell interaction on tumour cells, and vascular endothelial growth factor (VEGF)-induced angiogenesis in the BM milieu. Moreover, Natalizumab also blocked VEGF- and insulin-like growth factor 1 (IGF-1)-induced signalling sequelae triggering MM cell migration. In agreement with our in vitro results, Natalizumab inhibited tumour growth, VEGF secretion, and angiogenesis in a human severe combined immunodeficiency murine model of human MM in the human BM microenvironment. Importantly, Natalizumab not only blocked tumour cell adhesion, but also chemosensitized MM cells to bortezomib, in an in vitro therapeutically representative human MM-stroma cell co-culture system model. Our data therefore provide the rationale for the clinical evaluation of Natalizumab, preferably in combination with novel agents (e.g. bortezomib) to enhance MM cytotoxicity and improve patient outcome. [ABSTRACT FROM AUTHOR]

Summary Despite recent advances in treatment that have significantly improved overall survival, multiple myeloma (MM) remains incurable. Although rituximab, the first monoclonal antibody (MAb) evaluated in MM treatment, provided only very limited benefit, research is ongoing into a number of other MAbs directed against a variety of MM-related target antigens. Given the inherent immune dysfunction associated with MM, newer strategies that may enhance immune function in conjunction with antibodies may also provide a more fruitful clinical approach. Potential MAb targets in MM include growth factors and their receptors, other signalling molecules, and antigens expressed exclusively or predominantly on MM cells. MAb therapy involves a range of mechanisms, including antibody-dependent cellular cytotoxicity, complement-dependent cytotoxicity, interference with receptor-ligand interactions, and MAb conjugation to radioisotopes or toxins. The antigens currently targeted in MM therapy are discussed, along with the development status of the corresponding MAb therapeutics. Elotuzumab, an anti-CS1 MAb, has recently achieved clinically meaningful responses when combined with lenalidomide or bortezomib in patients with relapsed and relapsed/refractory MM. Other MAbs are also showing early promise. More ongoing clinical research is required to identify optimal combination regimens and biomarkers that may help predict response to specific MAb-based combinations. [ABSTRACT FROM AUTHOR]

Summary Novel therapies have transformed the treatment paradigm for multiple myeloma with significant improvements in survival now seen in both younger and older patients. Nonetheless, the disease is heterogeneous and high-risk patients in particular continue to have poor outcome. Moreover, the disease remains incurable. Efforts to refine risk stratification and disease characteristics continue with the use of cytogenetics, enhanced imaging techniques and other new technologies, such as genomics. The integration of novel therapies into induction therapy, consolidation and maintenance continues to evolve, and the appropriate use of combination strategies including proteasome inhibition and immunomodulatory treatment is emerging as a platform with application across the disease spectrum. Despite these advances, resistance to novel agents occurs and so the identification of new targets and the recognition of clonal heterogeneity are especially important as improvements to current treatment strategies are developed, with the goal of further improving patient outcome. [ABSTRACT FROM AUTHOR]

This open-label, dose escalation, multicentre phase 1/2 trial was undertaken to determine the safety and tolerability of the heat shock protein 90 (HSP90) inhibitor tanespimycin (100-340 mg/m) + bortezomib (0·7-1·3 mg/m) given on days 1, 4, 8 and 11 in each 21-d cycle. Phase 2 expansion occurred at the highest tested dose of tanespimycin at 340 mg/m and bortezomib at 1·3 mg/m. Seventy-two patients (median age, 60 years) with relapsed or relapsed and refractory multiple myeloma (MM) were enrolled; 63 patients (89%) completed the study. Tanespimycin in combination with bortezomib was well tolerated; few patients experienced significant neutropenia, constipation and anorexia (<10%), and no patients developed severe peripheral neuropathy. Among 67 efficacy-evaluable patients, there were 2 (3%) complete responses and 8 (12%) partial responses, for an objective response rate (ORR) of 27%, including 8 (12%) minimal responses. Response rates were highest among bortezomib-naive patients and proved durable in all patient subgroups, including those with bortezomib-refractory disease. Pharmacodynamic analyses indicated that tanespimycin plus bortezomib effectively inhibited the proteasome, as evidenced by decreased 20S proteasome activity, and inhibited HSP90, as reflected by increased HSP70 expression. The results of this study support additional studies of this combination approach in MM. [ABSTRACT FROM AUTHOR]

Cell cycle regulators, such as cyclin-dependent kinases (CDKs), are appealing targets for multiple myeloma (MM) therapy given the increased proliferative rates of tumour cells in advanced versus early stages of MM. We hypothesized that a multi-targeted CDK inhibitor with a different spectrum of activity compared to existing CDK inhibitors could trigger distinct molecular sequelae with therapeutic implications for MM. We therefore studied the small molecule heterocyclic compound NVP-LCQ195/AT9311 (LCQ195), which inhibits CDK1, CDK2 and CDK5, as well as CDK3 and CDK9. LCQ195 induced cell cycle arrest and eventual apoptotic cell death of MM cells, even at sub-μmol/l concentrations, spared non-malignant cells, and overcame the protection conferred to MM cells by stroma or cytokines of the bone marrow milieu. In MM cells, LCQ195 triggered decreased amplitude of transcriptional signatures associated with oncogenesis, drug resistance and stem cell renewal, including signatures of activation of key transcription factors for MM cells e.g. myc, HIF-1α, IRF4. Bortezomib-treated MM patients whose tumours had high baseline expression of genes suppressed by LCQ195 had significantly shorter progression-free and overall survival than those with low levels of these transcripts in their MM cells. These observations provide insight into the biological relevance of multi-targeted CDK inhibition in MM. [ABSTRACT FROM AUTHOR]

Heat shock protein 90 (HSP90) is a molecular chaperone that is induced in response to cellular stress and stabilizes client proteins involved in cell cycle control and proliferative/anti-apoptotic signalling. HSP90 is overexpressed in a range of cancers, and may contribute to tumour cell survival by stabilizing aberrant signalling proteins and by interfering with apoptosis. Tanespimycin, an HSP90 inhibitor, reduces tumour cell survival in vitro. In multiple myeloma (MM), HSP90 inhibition affects multiple client proteins that contribute to tumour cell survival, including the IGF1 receptor and the IL-6 receptor, and elements of the PI3/Akt, STAT3, and MAPK signalling pathways. HSP90 inhibition also abrogates the protective effect of bone marrow stromal cells and inhibits angiogenesis and osteoclastogenesis. Tanespimycin acts synergistically with the proteasome inhibitor bortezomib in MM cells and tumour explants, possibly reducing their ability to resist bortezomib-induced stress to the endoplasmic reticulum. The combination of tanespimycin and bortezomib has demonstrated significant and durable responses with acceptable toxicity in a phase I/II study in patients with relapsed and relapsed/refractory MM. HSP90 inhibition is a promising strategy in MM especially in combination with bortezomib; additional studies will further evaluate optimal dosings of candidate drugs and schedules, as well as confirm efficacy in comparative phase III trials. [ABSTRACT FROM AUTHOR]

PR-924 is an LMP-7-selective tripeptide epoxyketone proteasome inhibitor that covalently modifies proteasomal N-terminal threonine active sites. In the present study, we show that PR-924 inhibits growth and triggers apoptosis in multiple myeloma (MM) cell lines and primary patient MM cells, without significantly affecting normal peripheral blood mononuclear cells. PR-924-induced apoptosis in MM cells is associated with activation of caspase-3, caspase-8, caspase-9, BID, PARP and cytochrome-c release. In vivo administration of PR-924 inhibits tumour growth in human plasmacytoma xenografts. Results from SCID-hu model show a significant reduction in the shIL-6R levels in mice treated with PR-924 versus vehicle-control. PR-924 treatment was well tolerated as evidenced by the lack of weight loss. Importantly, treatment of tumour-bearing mice with PR-924, but not vehicle alone, prolonged survival. Our preclinical findings therefore validate immunoproteasome LMP-7 subunit as a novel therapeutic target in MM. [ABSTRACT FROM AUTHOR]

Tanespimycin (17-allylamino-17-demethoxygeldanamycin, 17-AAG) disrupts heat shock protein 90 (HSP90), a key molecular chaperone for signal transduction proteins critical to myeloma growth, survival and drug resistance. In previous studies, tanespimycin monotherapy was well tolerated and active in heavily pretreated patients with relapsed/refractory multiple myeloma (MM). Preclinical data have shown antitumour synergy between tanespimycin and bortezomib, with more pronounced intracellular accumulation of ubiquitinated proteins than either drug alone, an effect attributed to the synergistic suppression of chymotryptic activity in the 20S proteasome. HSP70 induction has been observed in all Phase 1 tanespimycin studies in which it has been measured, with several separate reports of HSP70 overexpression protecting against peripheral nerve injury. In this Phase 2, open-label multicentre study, we compared 1·3 mg/m2 bortezomib + three doses of tanespimycin: 50, 175 and 340 mg/m2 in heavily pretreated patients with relapsed and refractory MM and measured HSP70 expression and proteasome activity levels in plasma of treated patients. The study was closed prematurely for resource-based reasons, precluding dose comparison. Nonetheless, antitumour activity was observed, with promising response rates and promising severity of peripheral neuropathy. [ABSTRACT FROM AUTHOR]

Tanespimycin, a heat shock protein 90 (HSP90) inhibitor, induces apoptosis in drug-sensitive and -resistant MM cell lines and in tumour cells from patients with relapsed MM. In this phase 1 dose-escalation study, the safety, plasma pharmacokinetics, and biological/antitumour activity of tanespimycin were evaluated in heavily pretreated patients with relapsed/refractory MM. Tanespimycin (150–525 mg/m2) was given on days 1, 4, 8, and 11 of each 3-week cycle for up to 8 cycles. Non-haematological AEs included diarrhoea (59%), back pain (35%), fatigue (38%), and nausea (35%); haematological AEs included anaemia (24%) and thrombocytopenia (21%). One patient (3%) achieved minimal response (MR), with a progression-free survival (PFS) of 3 months, a 41% decrease from baseline in urine M protein, and a 33% decrease from baseline in serum M protein. Fifteen patients (52%) achieved SD with a median PFS of 2·1 months; 5/15 had reductions in serum M protein ranging from 7% to 38% and in urine M protein ranging from 6% to 91%. Mean HSP70 levels increased from day 1 h 0 to day 1 h 4 with further increases on day 11 h 0 and day 11 h 4, consistent with a therapeutic treatment effect. Tanespimycin monotherapy was well tolerated and demonstrated activity across all doses tested. [ABSTRACT FROM AUTHOR]

This study investigated the cytotoxicity and mechanism of action of AS703026, a novel, selective, orally bioavailable MEK1/2 inhibitor, in human multiple myeloma (MM). AS703026 inhibited growth and survival of MM cells and cytokine-induced osteoclast differentiation more potently (9- to 10-fold) than AZD6244. Inhibition of proliferation induced by AS703026 was mediated by G0-G1 cell cycle arrest and was accompanied by reduction of MAF oncogene expression. AS703026 further induced apoptosis via caspase 3 and Poly ADP ribose polymerase (PARP) cleavage in MM cells, both in the presence or absence of bone marrow stromal cells (BMSCs). Importantly, AS703026 sensitized MM cells to a broad spectrum of conventional (dexamethasone, melphalan), novel or emerging (lenalidomide, perifosine, bortezomib, rapamycin) anti-MM therapies. Significant tumour growth reduction in AS703026- vs. vehicle-treated mice bearing H929 MM xenograft tumours correlated with downregulated pERK1/2, induced PARP cleavage, and decreased microvessels in vivo. Moreover, AS703026 (<200 nmol/l) was cytotoxic against the majority of tumour cells tested from patients with relapsed and refractory MM (84%), regardless of mutational status of RAS and BRAF genes. Importantly, BMSC-induced viability of MM patient cells was similarly blocked within the same dose range. Our results therefore support clinical evaluation of AS703026, alone or in combination with other anti-MM agents, to improve patient outcome. [ABSTRACT FROM AUTHOR]

Our previous study showed that the novel proteasome inhibitor NPI-0052 induces apoptosis in multiple myeloma (MM) cells resistant to conventional and bortezomib (Velcade™, Takeda, Boston, MA, USA) therapies. In vivo studies using human MM-xenografts demonstrated that NPI-0052 is well tolerated, prolongs survival, and reduces tumour recurrence. These preclinical studies provided the basis for an ongoing phase-1 clinical trial of NPI-0052 in relapsed/refractory MM patients. Here we performed pharmacodynamic (PD) studies of NPI-0052 using human MM xenograft murine model. Our results showed that NPI-0052: (i) rapidly left the vascular compartment in an active form after intravenous (i.v.) administration, (ii) inhibited 20S proteasome chymotrypsin-like (CT-L, β5), trypsin-like (T-L, β2), and caspase-like (C-L, β1) activities in extra-vascular tumours, packed whole blood (PWB), lung, liver, spleen, and kidney, but not brain and (iii) triggered a more sustained (>24 h) proteasome inhibition in tumours and PWB than in other organs (<24 h). Tissue distribution analysis of radiolabeled compound (3H-NPI-0052) in mice demonstrated that NPI-0052 left the vascular space and entered organs as the parent compound. Importantly, treatment of MM.1S-bearing mice with NPI-0052 showed reduced tumour growth without significant toxicity, which was associated with prolonged inhibition of proteasome activity in tumours and PWB but not normal tissues. [ABSTRACT FROM AUTHOR]

This study characterized the preclinical anti-myeloma activity of VE465, a low molecular weight pan-Aurora kinase inhibitor. After 96-h drug exposure, several multiple myeloma (MM) cell lines were more sensitive to VE465 compared to non-malignant cells. The anti-MM activity of VE465 was maintained in the presence of interleukin-6 and, interestingly, enhanced by co-culture with stromal cells. However, primary MM cells were less responsive than cell lines. Combinations with dexamethasone (Dex), doxorubicin (Doxo) and bortezomib showed no antagonism. Our study highlights the potential role of the tumour microenvironment in modulating the activity of this drug class. [ABSTRACT FROM AUTHOR]

This subgroup analysis of the phase III APEX (Assessment of Proteasome Inhibition for Extending Remissions) trial examined whether prior exposure to specific therapies affected the relative efficacy of bortezomib versus dexamethasone in relapsed/refractory myeloma. Time to progression and overall survival were superior with bortezomib in all subgroups, with no evidence of interaction between any prior therapies and assignment to study therapy. Patients with prior thalidomide exposure had worse outcomes overall, but neither prior thalidomide nor prior autologous stem cell transplantation affected the relative efficacy of bortezomib versus dexamethasone. These results confirm the superiority of bortezomib over dexamethasone, regardless of prior exposure to specific therapies (clinicaltrials.gov: NCT00048230). [ABSTRACT FROM AUTHOR]

The frequency, characteristics and reversibility of bortezomib-associated peripheral neuropathy were evaluated in the phase III APEX (Assessment of Proteasome Inhibition for Extending Remissions) trial in patients with relapsed myeloma, and the impact of a dose-modification guideline on peripheral neuropathy severity and reversibility was assessed. Patients received bortezomib 1·3 mg/m2 (days 1, 4, 8, 11, eight 21-d cycles, then days 1, 8, 15, 22, three 35-d cycles); bortezomib was held, dose-reduced or discontinued depending on peripheral neuropathy severity, according to a protocol-specified dose-modification guideline. Overall, 124/331 patients (37%) had treatment-emergent peripheral neuropathy, including 30 (9%) with grade ≥3; incidence and severity were not affected by age, number/type of prior therapies, baseline glycosylated haemoglobin level, or diabetes history. Grade ≥3 incidence appeared lower versus phase II trials (13%) that did not specifically provide dose-modification guidelines. Of patients with grade ≥2 peripheral neuropathy, 58/91 (64%) experienced improvement or resolution to baseline at a median of 110 d, including 49/72 (68%) who had dose modification versus 9/19 (47%) who did not. Efficacy did not appear adversely affected by dose modification for grade ≥2 peripheral neuropathy. Bortezomib-associated peripheral neuropathy is manageable and reversible in most patients with relapsed myeloma. Dose modification using a specific guideline improves peripheral neuropathy management without adversely affecting outcome. [ABSTRACT FROM AUTHOR]

The Clinical Response and Efficacy Study of Bortezomib in the Treatment of Relapsing Multiple Myeloma (CREST) demonstrated substantial activity with two dose levels of bortezomib (1·0 and 1·3 mg/m2), alone or with dexamethasone, in relapsed or refractory multiple myeloma. We present updated survival analyses after prolonged follow-up (median >5 years). One- and 5-year survival rates were 82% and 32%, respectively, in the 1·0 mg/m2 group ( n = 28), and 81% and 45%, respectively, in the 1·3 mg/m2 group ( n = 26). Notable survival, response, and time-to-progression data suggest that a bortezomib starting dose of 1·3 mg/m2 is preferred. If bortezomib dose reduction is required, the 1·0 mg/m2 dose still offers patients a substantial survival benefit. [ABSTRACT FROM AUTHOR]