No abstract

In a randomized, phase 3 study, superior complete/near-complete response (CR/nCR) rates and extended progressionfree survival were demonstrated with bortezomib-thalidomide-dexamethasone (VTD) versus thalidomide-dexamethasone (TD) as induction therapy before, and consolidation after, double autologous stem cell transplantation for newly diagnosed myeloma patients (intention-totreat analysis; VTD, n ‫؍‬ 236; TD, n ‫؍‬ 238). This per-protocol analysis (VTD, n ‫؍‬ 160; TD, n ‫؍‬ 161) specifically assessed the efficacy and safety of consolidation with VTD or TD. Before starting consolidation, CR/nCR rates were not significantly different in the VTD (63.1%) and TD arms (54.7%). After consolidation, CR (60.6% vs 46.6%) and CR/nCR (73.1% vs 60.9%) rates were significantly higher for VTDtreated versus TD-treated patients. VTD consolidation significantly increased CR and CR/nCR rates, but TD did not (McNemar test). With a median follow-up of 30.4 months from start of consolidation, 3-year progression-free survival was significantly longer for the VTD group (60% vs 48% for TD). Grade 2 or 3 peripheral neuropathy (8.1% vs 2.4%) was more frequent with VTD (grade 3, 0.6%) versus TD consolidation. The superior efficacy of VTD versus TD as induction was retained despite readministration as consolidation therapy after double autologous transplantation. VTD consolidation therapy significantly contributed to improved clinical outcomes observed for patients randomly assigned to the

IntroductionOver the last decade, major advances in the treatment of multiple myeloma (MM) have been reported with the use of autologous stem-cell transplantation [1][2][3][4] and, more recently, of novel agents targeting the tumor clone and the bone marrow microenvironment. 5 In this setting, thalidomide represents a new treatment paradigm because of its alternative mechanisms of action that include disruption of myeloma-bone marrow stromal cell interactions, inhibition of cytokine secretion, and immunomodulatory effects. The observation that increased bone marrow angiogenesis correlates with advanced phases of MM, 6 along with the welldocumented in vitro antiangiogenic activity of thalidomide, 7 led to the investigational use of this agent in patients with advanced and refractory MM. 8 Response rates in the 30% range initially reported by Singhal et al 8 were extended and confirmed by other groups (for a review, see Cavenagh and Oakervee 9 and Dimopoulos et al 10 ). Subsequent combination of thalidomide with dexamethasone increased the rate of response up to 50% to 55%, 11,12 suggesting a synergism between these agents and providing the rationale for their use as primary therapy for patients with symptomatic MM. Results of 3 phase-2 studies with thalidomide-dexamethasone (Thal-Dex) in preparation for subsequent autologous transplantation 13-15 and a randomized comparison of Thal-Dex with dexamethasone alone 16 were promising in terms of response rate and collection of adequate quantities of peripheral blood stem cells (PBSCs). Based on these data, Thal-Dex has been proposed, and is currently accepted at many centers, as a front-line treatment option for patients with symptomatic MM, particularly if it is planned to offer subsequent high-dose therapy with autologous transplantation. However, no comparative study of Thal-Dex with vincristinedoxorubicin-dexamethasone (VAD), the reference treatment used so far to reduce tumor cell mass before autologous transplantation, has been reported. To address this issue, we performed a retrospective matched case-control analysis of 200 patients with symptomatic MM who were primarily treated with Thal-Dex (n ϭ 100) or VAD (n ϭ 100) in preparation for autologous stem-cell transplantation as part of 2 consecutive studies conducted from 1996 to 2004. Table 1; the 2 groups were comparable with respect to the major presenting variables known to potentially affect clinical outcome. Both studies were approved by local ethical committees of participating centers. Informed consent was provided according to the Declaration of Helsinki. Patients, materials, and methods Patients and criteria of matching Study design and treatment regimensBy design of both studies, Thal-Dex and VAD were planned to be administered for 4 months in an attempt to reduce tumor cell mass before collection of PBSCs and subsequent autologous transplantation. Details on treatment regimens were given elsewhere. 4,15 Briefly, thalidomide was given orally at the starting dose of 100 mg/d for 14 days and then increa...

No abstract

In this study, we demonstrate expression and examined the biologic sequelae of PI3K/p110␦ signaling in multiple myeloma ( IntroductionThe bone marrow (BM) microenvironment plays a crucial role in pathogenesis of multiple myeloma (MM) by promoting cell proliferation, survival, migration, and drug resistance. [1][2][3][4] The PI3K/AKT pathway mediates growth and drug resistance in MM cells and also plays a significant role in autophagy. 5,6 PI3K is activated via upstream tyrosine kinase-associated receptors for growth factors, cytokines, antigens, and costimulatory molecules. It in turn activates AKT, which mediates cell proliferation, cell cycle, apoptosis, and autophagy. 7 Class IA PI3K consists of 5 isoforms of regulatory subunits (p85␣, p50␣, p55␣, p85␤, and p55␥), which interact with class IA isoforms. Class IA PI3K is composed of p110␣, -␤, and -␦ isoforms. 8 Among the 8 distinct mammalian isoforms of PI3K, class I PI3Ks are responsible for Akt activation. Importantly, p110␦ is expressed in many cancers, including colon and bladder carcinoma, glioblastoma, and acute myeloid leukemia blasts. 9,10 In the current study, we demonstrate high expression of p110␦ in patient MM cells. Previous studies have shown that CAL-101, a potent and selective p110␦ inhibitor, has broad antitumor activity against cancer cells of hematologic origin. 11,12 Moreover, inhibition of p110␦ induces cleavage of caspases and LC3, consistent with apoptotic and autophagic cell death, respectively. Here we show that p110␦ blockade with CAL-101, a potent and selective p110␦ inhibitor, inhibits MM cell growth even in the presence of interleukin-6 (IL-6), insulin-like growth factor-1 (IGF-1), or bone marrow stromal cells (BMSCs), associated with decreased phosphorylation of AKT and P70S6k. We also confirmed inhibition of human MM cell growth triggered by p110␦ inhibition in our xenograft mouse models of human MM. These studies therefore show that small molecule inhibitors of p110␦ trigger significant anti-MM cytotoxicity both in vitro and in vivo, providing the framework for their clinical evaluation to improve patient outcome in MM. Methods Materialsp110␦ inhibitor CAL-101 and IC488743 were provided by Calistoga Pharmaceuticals. CAL-101 was dissolved in dimethyl sulphoxide at 10mM and stored at Ϫ20°C for in vitro study. IC488743 was dissolved in 1% carboxyl methylcellulose/0.5% Tween 80 and stored at 4°C for in vivo study. Recombinant human p110␣, ␤, ␥, and ␦ were reconstituted with sterile phosphate-buffered saline (PBS) containing 0.1% bovine serum albumin. Bortezomib was provided by Millennium Pharmaceuticals. 3-Methyladenine was purchased from Sigma-Aldrich. The publication costs of this article were defrayed in part by page charge payment. Therefore, and solely to indicate this fact, this article is hereby marked ''advertisement'' in accordance with 18 USC section 1734. Cell culture Dex 1460BLOOD, 2 SEPTEMBER 2010 ⅐ VOLUME 116, NUMBER 9For personal use only. on March 28, 2019. by guest www.bloodjournal.org From Germany). LB human MM ce...

Aurora-A is a mitotic kinase that regulates mitotic spindle formation and segregation. In multiple myeloma (MM), high Aurora-A gene expression has been correlated with centrosome amplification and proliferation; thus, inhibition of Aurora-A in MM may prove to be therapeutically beneficial. Here we assess the in vitro and in vivo anti-MM activity of MLN8237, a small-molecule Aurora-A kinase inhibitor. Treatment of cultured MM cells with MLN8237 results in mitotic spindle abnormalities, mitotic accumulation, as well as inhibition of cell proliferation through apoptosis and senescence. In addition, MLN8237 up-regulates p53 and tumor suppressor genes p21 and p27. Combining MLN8237 with dexamethasone, doxorubicin, or bortezomib induces synergistic/ additive anti-MM activity in vitro. In vivo anti-MM activity of MLN8237 was confirmed using a xenograft-murine model of human-MM. Tumor burden was significantly reduced (P ‫؍‬ .007) and overall survival was significantly increased (P < . IntroductionMultiple myeloma (MM) is a B-cell disease characterized by accumulation of malignant plasma cells in the bone marrow (BM), bone lesions, and immunodeficiency. Genetic analysis shows that approximately 55% to 60% of MM patients have a hyperdiploid karyotype, which confers a better prognosis than nonhyperdiploid disease. 1 The most frequent chromosomal abnormalities observed in nonhyperdiploid MM are translocations between immunoglobulin heavy chain gene located on chromosome 14q32 and an oncogene chromosome 11q13 (CYCLIN D1), 4p16.3 (FGFR3 and MMSET), 6p21 (CYCLIN D3), 16q23 (MAF), or 20q11 (MAFB); or less frequently, the immunoglobulin light chain locus (2p12, or 22q11). 2 During cell proliferation, activation of each cell-cycle phase is dependent on the progress and completion of the previous one. Regulation of the cell cycle involves detecting and repairing genetic damage, as well as controlling various checkpoints to prevent uncontrolled cell division. MM cells are further influenced by the BM microenvironment because adhesion of MM cells to extracellular-matrix proteins supports cell adhesion-mediated drug resistance. In addition, binding of MM cells to BM accessory cells induces secretion of cytokines, which further promote growth, survival, and migration of tumor cells, as well as resistance to conventional chemotherapy. 2,3 Aberrant or overexpression of D-type cyclins is ubiquitous in MM, 4,5 and Aurora kinases regulate cell-cycle checkpoints 6 and cell cycle-regulatory molecules, including cyclins and cyclindependent kinases. [7][8][9] Aurora serine/threonine kinases localize in the centrosome and play a crucial role in cell division by regulating chromatid segregation in mitotic cells 10 ; moreover, defective chromatid segregation causes genetic instability, leading to tumorigenesis. 11 They were first identified in Xenopus Eg2, yeast Ipl1, and Drosophila aurora. The human genome expresses 3 members of the mitotic Aurora kinase family: Aurora-A serine/threonine kinases, Aurora-B serine/threonine kinases, and Aurora-C s...

Purpose: We investigated the antitumor effect of murine/human chimeric CD138-specific monoclonal antibody nBT062 conjugated with highly cytotoxic maytansinoid derivatives against multiple myeloma (MM) cells in vitro and in vivo. Experimental Design: We examined the growth inhibitory effect of BT062-SPDB-DM4, BT062-SMCC-DM1, and BT062-SPP-DM1 against MM cell lines and primary tumor cells from MM patients. We also examined in vivo activity of these agents in murine MM cell xenograft model of human and severe combined immunodeficient (SCID) mice bearing implant bone chips injected with human MM cells (SCID-hu model). Results: Anti-CD138 immunoconjugates significantly inhibited growth of MM cell lines and primary tumor cells from MM patients without cytotoxicity against peripheral blood mononuclear cells from healthy volunteers. In MM cells, they induced G 2 -M cell cycle arrest, followed by apoptosis associated with cleavage of caspase-3, caspase-8, caspase-9, and poly(ADP-ribose) polymerase. Nonconjugated nBT062 completely blocked cytotoxicity induced by nBT062-maytansinoid conjugate, confirming that specific binding is required for inducing cytotoxicity. Moreover, nBT062-maytansinoid conjugates blocked adhesion of MM cells to bone marrow stromal cells. The coculture of MM cells with bone marrow stromal cells protects against dexamethasone-induced death but had no effect on the cytotoxicity of immunoconjugates. Importantly, nBT062-SPDB-DM4 and nBT062-SPP-DM1 significantly inhibited MM tumor growth in vivo and prolonged host survival in both the xenograft mouse models of human MM and SCID-hu mouse model. Conclusion: These results provide the preclinical framework supporting evaluation of nBT062-maytansinoid derivatives in clinical trials to improve patient outcome in MM.The cell surface proteoglycan CD138 (syndecan-1) is an integral membrane protein acting as a receptor for the extracellular matrix. Within the normal human hematopoetic compartment, CD138 is expressed on differentiated plasma cells and is a primary diagnostic marker of multiple myeloma (MM; ref. 1). The large extracellular domain of CD138 binds via its heparin sulfate chains to soluble extracellular molecules, including the growth factors epidermal growth factor, fibroblast growth factor, and hepatocyte growth factor, and to insoluble extracellular molecules, such as collagen and fibronectin (2, 3). CD138 also mediates cell-cell adhesion through interactions with heparinbinding molecules. Studies of plasma cell differentiation show that CD138 is a differentiation antigen (4) and a coreceptor for MM growth factors (5).Several monoclonal antibodies (mAb; i.e.,

The PI3K/Akt/mTOR pathway mediates multiple myeloma (MM) cell proliferation, survival, and development of drug resistance, underscoring the role of mTOR inhibitors such as rapamycin with potential anti-MM activity. However, recent data demonstrate a positive feedback loop from mTOR/S6K1 to Akt, whereby Akt activation confers resistance to mTOR inhibitors. We confirmed that suppression of mTOR signaling in MM cells by rapamycin was associated with upregulation of Akt phosphorylation. We hypothesized that inhibiting this positive feedback by a potent Akt inhibitor perifosine would augment rapamycin-induced cytotoxicity in MM cells. Perifosine inhibited rapamycin-induced p-Akt, resulting in enhanced cytotoxicity in MM.1S cells even in the presence of IL-6, IGF-1 or bone marrow stromal cells. Moreover, rapamycin induced autophagy in MM.1S MM cells as evidenced by electron microscopy and immunocytochemistry, was augmented by perifosine. Combination therapy increased apoptosis detected by Annexin/PI analysis and caspase/PARP cleavage. Importantly, in vivo antitumor activity and prolongation of survival in a MM mouse xenograft model after treatment was enhanced with combination of nab-rapamycin and perifosine. Utilizing the in silico predictive analysis we confirmed our experimental findings of this drug combination on PI3K, Akt, mTOR kinases, and the caspases. Our data suggests that mutual suppression of the PI3K/Akt/mTOR pathway by rapamycin and perifosine combination induces synergistic MM cell cytotoxicity, providing the rationale for clinical trials in patients with relapsed / refractory MM.