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Summary: The phase 3 PANORAMA‐1 trial led to regulatory approvals of panobinostat (PAN) in combination with bortezomib (BTZ) and dexamethasone (DEX) for the treatment of multiple myeloma after ≥2 prior regimens, including BTZ and an immunomodulatory drug. Patient‐reported outcomes (PROs) were assessed in PANORAMA‐1, with data available for 73 patients in the PAN + BTZ + DEX arm and 74 patients in the placebo (PBO) + BTZ + DEX arm. Per the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire‐Core 30 (EORTC QLQ‐C30), global health status/quality of life (QoL) scores initially declined with PAN + BTZ + DEX during the first 24 weeks before approaching baseline scores and remaining steady during the next 24 weeks, with no difference between arms at Week 48. The EORTC QLQ‐Myeloma module (EORTC QLQ‐MY20) demonstrated initial improvements and subsequent stabilization of disease symptom scores in both arms and initial worsening and subsequent improvement of side effects of treatment scores, with the initial worsening more pronounced and recovery less pronounced with PAN + BTZ + DEX. Functional Assessment of Cancer Therapy/Gynecologic Oncology Group‐Neurotoxicity scores remained relatively stable and similar between the arms. Overall, these PRO findings support the addition of PAN to the BTZ+DEX regimen as an efficacious treatment option, with limited symptomatology and impact on patients’ QoL. The reported results are based on a descriptive analysis of the data. No formal statistical tests have been performed. [ABSTRACT FROM AUTHOR]

Summary: Patients with multiple myeloma (MM) have improved treatment options, including immunomodulatory drugs (IMiDs) and proteasome inhibitors (PIs). Despite their efficacy, increased rates of cardiovascular (CV) complications occur in patients exposed to some of these therapies. While previous research has focused on identifying the toxicities inherent to each specific agent, the CV side effects may be potentiated by the combination of PIs and IMiDs plus dexamethasone. We present a patient with MM with recurrent cardiotoxicity only when exposed to combination PI and IMiD‐based therapy. We also review the literature in this context, and propose a potential algorithm for cardiotoxicity prevention in this population. [ABSTRACT FROM AUTHOR]

CD38 is highly and uniformly expressed on multiple myeloma (MM) cells, and at relatively low levels on normal lymphoid and myeloid cells, and in some tissues of nonhematopoietic origin. CD38 is a transmembrane glycoprotein with ectoenzymatic activity, and also functions as a receptor and adhesion molecule. Altogether, this has triggered the development of several CD38 antibodies including daratumumab (fully human), isatuximab (chimeric), and MOR202 (fully human). CD38 antibodies have pleiotropic mechanisms of action including Fc-dependent immune-effector mechanisms, direct apoptotic activity, and immunomodulatory effects by the elimination of CD381 immune-suppressor cells. CD38-targeting antibodies are generally well tolerated and induce partial response or better in ~30% of heavily pretreated MM patients as monotherapy. Based on their distinct mechanisms of action, favorable toxicity profile, and single-agent activity, CD38 antibodies are attractive partners in combination regimens. Indeed, deep responses and prolonged progression-free survival can be achieved in relapsed/refractory MM patients when CD38 antibodies are combined with immunomodulatory agents or proteasome inhibitors. Infusion-related reactions, which typically occur during the first infusion, are the most frequent adverse events. Attention should also be paid to the interference of CD38 antibodies with certain laboratory assays, which may complicate response evaluation and blood compatibility testing. Several studies are currently examining the role of CD38-based therapies in newly diagnosed and highrisk smoldering MM. Furthermore, CD38 antibodies are currently also under investigation in other hematologic malignancies, including acute lymphoblastic leukemia, natural killer/T-cell lymphoma, and acute myeloid leukemia, as well as in solid tumors. [ABSTRACT FROM AUTHOR]

Marizomib ( MRZ) is an irreversible, pan-subunit proteasome inhibitor ( PI) in clinical development for relapsed/refractory multiple myeloma ( RRMM) and glioma. This study analysed MRZ, pomalidomide ( POM) and low-dose dexamethasone (Lo- DEX) [ PMD] in RRMM to evaluate safety and determine the maximum tolerated dose ( MTD) and/or recommended Phase 2 dose ( RP2D). Intravenous MRZ (0·3-0·5 mg/m2) was administered over 2 h on days 1, 4, 8, 11; POM (3-4 mg) on days 1-21; and Lo- DEX (5 or 10 mg) on days 1, 2, 4, 5, 8, 9, 11, 12, 15, 16, 22 and 23 of every 28-day cycle. Thirty-eight patients were enrolled that had received a median of 4 (range 1-10) prior lines of therapy; all patients received prior lenalidomide and bortezomib. No dose-limiting toxicities ( DLTs) were observed and 0·5 mg/m2 MRZ was determined to be the RP2D. The most common treatment-related ≥Grade 3 adverse events were: neutropenia (11/38 patients: 29%), pneumonia (4/38 patients 11%), anaemia (4/38 patients; 11%) and thrombocytopenia (4/38 patients; 11%). The overall response rate and clinical benefit rate was 53% (19/36) and 64% (23/36), respectively. In conclusion, PMD was well tolerated and demonstrated promising activity in heavily pre-treated, high-risk RRMM patients. [ABSTRACT FROM AUTHOR]

Marizomib, a natural marine product, is an irreversible proteasome inhibitor currently under investigation in relapsed-refractory multiple myeloma ( RRMM) and malignant glioma. Central nervous system-multiple myeloma ( CNS- MM) is a rare manifestation of extra-medullary disease with few therapeutic options, highlighting the unmet clinical need in these patients. Marizomib demonstrated encouraging activity in RRMM and has emerging clinical activity in glioma, making it a potential CNS- MM therapeutic intervention. Herein, we present two patients with RRMM and CNS involvement who benefited from marizomib-based therapy. These cases provide the first proof of principle for further exploring marizomib in CNS- MM patients. [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]

Panobinostat is a potent pan-deacetylase inhibitor that affects the growth and survival of multiple myeloma (MM) cells through alteration of epigenetic mechanisms and protein metabolism. Panobinostat plus bortezomib and dexamethasone (PAN-BTZ-Dex) led to a significant increase in progression-free survival (PFS) vs placebo plus bortezomib and dexamethasone (Pbo-BTZ-Dex) in patients with relapsed or relapsed and refractory MM in the phase 3 PANORAMA 1 trial. This subgroup analysis evaluated outcomes in patients in the PANORAMA 1 trial based on prior treatment: a prior immunomodulatory drug (IMiD; n = 485), prior bortezomib plus an IMiD (n = 193), and ≥2 prior regimens including bortezomib and an IMiD (n = 147). Median PFS with PAN-BTZ-Dex vs Pbo-BTZ-Dex across subgroups was as follows: prior IMiD (12.3 vs 7.4 months; hazard ratio [HR], 0.54; 95% confidence interval [CI], 0.43-0.68), prior bortezomib plus IMiD (10.6 vs 5.8 months; HR, 0.52; 95% CI, 0.36-0.76), and ≥2 prior regimens including bortezomib and an IMiD (12.5 vs 4.7 months; HR, 0.47; 95% CI, 0.31-0.72). Common grade 3/4 adverse events and laboratory abnormalities in patients who received PAN-BTZ-Dex across the prior treatment groups included thrombocytopenia, lymphopenia, neutropenia, diarrhea, and asthenia/fatigue. Incidence of on-treatment deaths among patients who received prior bortezomib and an IMiD (regardless of number of prior regimens) was similar between treatment arms. This analysis demonstrated a clear PFS benefit of 7.8 months with PAN-BTZ-Dex among patients who received ≥2 prior regimens including bortezomib and an IMiD, a population with limited treatment options and poorer prognosis. [ABSTRACT FROM AUTHOR]

Recently, outcomes for patients with multiple myeloma have improved dramatically due to improved and innovative therapies. However, most patients will either relapse or become refractory to current therapy. Thus, a significant unmet need remains for novel agents to treat this patient population. Panobinostat, a potent pan-deacetylase inhibitor with a unique mechanism of action targeting both epigenetic regulation of gene expression and protein metabolism, has preclinical synergy with a number of agents, including the proteasome inhibitor bortezomib. In a phase 3 trial of panobinostat with bortezomib and dexamethasone, addition of panobinostat significantly prolonged the median progression-free survival of patients with relapsed or relapsed and refractory multiple myeloma. This review focuses on clinical development of panobinostat, with particular emphasis on pharmacokinetics and adverse event management. [ABSTRACT FROM PUBLISHER]

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]

Toward our goal of personalized medicine, we comprehensively profiled pre-treatment malignant plasma cells from multiple myeloma patients and prospectively identified pathways predictive of favourable response to bortezomib-based treatment regimens. We utilized two complementary quantitative proteomics platforms to identify differentially-regulated proteins indicative of at least a very good partial response ( VGPR) or complete response/near complete response ( CR/ nCR) to two treatment regimens containing either bortezomib, liposomal doxorubicin and dexamethasone ( VDD), or lenalidomide, bortezomib and dexamethasone ( RVD). Our results suggest enrichment of 'universal response' pathways that are common to both treatment regimens and are probable predictors of favourable response to bortezomib, including a subset of endoplasmic reticulum stress pathways. The data also implicate pathways unique to each regimen that may predict sensitivity to DNA-damaging agents, such as mitochondrial dysfunction, and immunomodulatory drugs, which was associated with acute phase response signalling. Overall, we identified patterns of tumour characteristics that may predict response to bortezomib-based regimens and their components. These results provide a rationale for further evaluation of the protein profiles identified herein for targeted selection of anti-myeloma therapy to increase the likelihood of improved treatment outcome of patients with newly-diagnosed myeloma. [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]

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]

Rapid development of the small molecule proteasome inhibitor bortezomib has yielded important clinical benefit for patients with multiple myeloma. Early phase clinical trials suggest the agent has similar efficacy in Waldenstroms Macroglobulinemia. Optimization of bortezomib-based therapy, though, requires an understanding of the various challenges associated with use of the drug. This review highlights the rationale for bortezomib therapy in patients with multiple myeloma and Waldenstroms Macroglobulinemia, mechanisms of bortezomib resistance, important therapy-related side effects, and new directions for the use of proteasome inhibitors in these disorders. [ABSTRACT FROM AUTHOR]

In this article the author discusses the novel agents relative to the management of multiple myeloma (MM) and improved patient outcomes. He mentions that combinations of novel agents such as thalidomide, lenalidomide and bortezomib with MM chemotherapeutics have produced significant improvements in response rate, remission duration, and overall survival. The author is critical on the treatment-related toxicity of the therapy.

Abstract: New treatment options are urgently needed for patients with relapsed multiple myeloma (MM) who are refractory to thalidomide, lenalidomide, and bortezomib therapy. Pomalidomide, a second-generation immunomodulatory agent, has been shown to exert direct antiproliferative actions on MM cells, effects on the bone-marrow microenvironment, and immunomodulation. In phase I clinical trials, pomalidomide has demonstrated promising response rates in patients with relapsed and/or refractory MM, with manageable toxicity. In phase II trials pomalidomide, 2–4mg/daily, given continuously or on days 1–21 of a 28-day cycle, in combination with dexamethasone, has been associated with high quality and durable clinical responses in patients who are refractory to lenalidomide, bortezomib, or both. Pomalidomide appears to be well tolerated; hematologic toxicities are the most commonly reported adverse events and peripheral neuropathy is rare. Phase III trials are currently underway to determine the optimal dose and combination regimen of pomalidomide in the treatment of MM. [Copyright &y& Elsevier]