Search

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]

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: 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]

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]

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]