New Strategies in the Treatment of Multiple Myeloma

Published OnlineFirst March 20, 2013; DOI: 10.1158/1078-0432.CCR-12-1881

Clinical Cancer CCR New Strategies Research

Nikhil C. Munshi1,2 and Kenneth C. Anderson2

Abstract Multiple myeloma is the second most common hematologic malignancy affecting terminally differen- tiated plasma cells. Although high-dose chemotherapy and autologous stem cell transplantation have improved survival in younger patients, the natural history of multiple myeloma has been changed with the availability of six new agents approved in the past 10 years (thalidomide, bortezomib, lenalidomide, liposomal doxorubicin, carfilzomib, and pomalidomide). Despite this significant improvement in the overall outcome, multiple myeloma remains incurable in the majority of patients, prompting a continued search for additional therapeutic options. Extensive molecular and genomic characterization of multiple myeloma cells in their bone marrow milieu, which affects myeloma cell growth and survival, has provided a number of novel drugable targets and pathways. Perturbation of protein catabolism at multiple levels has become an important target in multiple myeloma. Similarly, improvements in monoclonal antibody generation and vaccine development, along with identification of a number of cell surface and cellular targets, have led to the development of various strategies, including antibodies and antibody–drug conjugates that are under investigation preclinically and in early clinical studies. We propose that eventually, molecularly informed multiagent combination therapies will be required to eliminate the multiple myeloma cell clone for long-term disease control. Clin Cancer Res; 19(13); 3337–44. 2013 AACR.

Background survival has increased to more than 7 years as a direct result Multiple myeloma is characterized by excess bone mar- (1). Parallel advances in the genomics of multiple myeloma row plasma cells in association with monoclonal protein in have defined additional disease heterogeneity and complex- the blood and/or urine, often associated with bone destruc- ity as well as providing the rationale for personalized single- tion, anemia, hypercalcemia, and renal dysfunction. It agent and combination therapies. affected 21,700 new individuals in the United States in 2012, with a prevalence of 71,213 total patients, and 10,710 On the Horizon patients died from the disease. Fifty years ago, the advent of Going forward, the major translational research focus in melphalan and prednisone extended patient median sur- multiple myeloma is in 4 main areas: development of novel vival to 2 to 3 years, and high-dose therapy followed by stem agents targeting the multiple myeloma cell in the bone cell rescue has prolonged median survival to 4 to 5 years. marrow microenvironment, development of immune (vac- Increasing awareness of the role of the bone marrow in cine and adoptive immunotherapy) strategies, develop- supporting growth, survival, and drug resistance of multiple ment of rationally based combination therapies, and use myeloma cells, along with concomitant development of of genomics for improved classification and personalized novel agents to overcome cell adhesion–mediated drug therapy. resistance to conventional therapies, has transformed the treatment paradigm in multiple myeloma. Specifically, the Targeting protein catabolism proteasome inhibitor, bortezomib, and immunomodula- Normal cellular homeostasis is maintained by a balanced tory drugs, thalidomide and lenalidomide, have formed the regulation of protein synthesis and degradation. The ubi- framework for multiple new treatment options for newly quitin proteasome system (UPS) is a nonlysosomal intra- diagnosed and relapsed/refractory multiple myeloma as cellular protein degradation pathway mediated via protea- well as maintenance therapy. Most importantly, median some holoenzymes, ubiquitin ligases, and deubiquitylating enzymes (DUB; ref. 2). Deregulation of the UPS pathway is linked to the pathogenesis of various human diseases, Authors' Affiliations: 1Veterans Administration Boston Healthcare Sys- tem, Boston; and 2Jerome Lipper Multiple Myeloma Center, Dana-Farber including multiple myeloma, and therefore inhibitors of Cancer Institute, Harvard Medical School, Boston, Massachusetts UPS pathways either at the level of proteasomal or ubiqui- Corresponding Author: Nikhil C. Munshi, Dana-Farber Cancer Institute, tylating/deubiquitylating enzymes offer great promise as a 450 Brookline Avenue, M230, Boston, MA 02215. Phone: 617-632-4166; novel therapeutic strategy (Fig. 1). We and others have Fax: 617-632-5829; E-mail: [email protected] characterized targeting of the UPS using our in vitro and doi: 10.1158/1078-0432.CCR-12-1881 in vivo models of the multiple myeloma cell in the bone 2013 American Association for Cancer Research. marrow milieu, specifically elucidating the molecular and

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Inhibitors of Inhibitors of deubiquitylating E3 ubiquitin ligase UPS enzymes

Deubiquitylating enzymes E3 ubiquitin ligases

Exogenous Figure 1. Schematic ubiquitin representation of the ubiquitin proteasome system. UPS function is mediated via a large number of indicated components, suggesting many potential sites of

Proteasome pharmacologic intervention.

Proteasome Inhibitors of ubiquitin-substrate/ proteasome interface E1/E2 enzymes

Proteasome Inhibitors of ubiquitin inhibitors activation/transfer

cellular mechanisms whereby proteasome inhibitors target lack of neuropathy (5–7). In bortezomib-na€ve patients, tumor cells, host–tumor interactions, and the bone marrow response rates are at least doubled, and combination trials microenvironment to overcome conventional drug resis- of carfilzomib with lenalidomide and dexamethasone show tance. Our preclinical and clinical studies led to the U.S. a remarkable extent and frequency of response both in Food and Drug Administration (FDA) approval of bortezo- relapsed and in newly diagnosed multiple myeloma. Anoth- mib for relapsed/refractory and newly diagnosed multiple er second-generation proteasome inhibitor, marizomib, myeloma. Although bortezomib represents a major advance, blocked chymotryptic-, tryptic-, and caspase-like protea- not all patients respond and those that respond, relapse. some activities and overcame bortezomib resistance in More recent studies have therefore defined mechanisms of preclinical models. Ongoing clinical studies have defined resistance to proteasome inhibitors and strategies to over- the dose and schedule and early signs of efficacy (8). MLN come them, including second-generation proteasome inhi- 9708 is an oral boron-containing proteasome inhibitor that bitors and scientifically informed combination therapies. has a shorter proteasome dissociation half-life than borte- Novel proteasome inhibitors. Second-generation protea- zomib, with improved pharmacokinetics and antitumor some inhibitors differ qualitatively and quantitatively from activity both in vitro and in vivo (9, 10). Already, MLN9708 bortezomib in their pattern of proteasome inhibition and has shown single-agent clinical activity in relapsed refrac- can overcome bortezomib resistance in preclinical models. tory multiple myeloma as well as high-response rates when Carfilzomib, a recently approved agent for relapsed multi- it was combined with lenalidomide and dexamethasone in ple myeloma that is an epoxyketone that irreversibly and an all-oral regimen to treat newly diagnosed multiple covalently binds to the chymotrypic site of the proteasome, myeloma. resulting in increased extent and duration of inhibition Deubiquitylating enzyme inhibitors. Bortezomib has compared with bortezomib (3, 4). In relapsed and borte- validated targeting protein homeostasis as an effective ther- zomib-refractory multiple myeloma, phase I/II clinical apeutic strategy in multiple myeloma. More recent efforts trials have shown 20% single-agent responses lasting 8 have focused on discovery and development of small-mol- months, with prolongation of survival to 15 months and ecule inhibitors of DUBs, another major component of UPS

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New Strategies in Myeloma

(2). Our studies show increased expression and activity of multiple myeloma cells in bone marrow, inhibit constitu- the DUB USP7 in multiple myeloma cells versus normal tive and multiple myeloma cell binding–induced transcrip- plasma cells, and that its inhibition by P5091 triggers tion and secretion of cytokines, inhibit angiogenesis, and ubiquitylation and degradation of HDM2, thereby activat- modulate T-cell, natural killer (NK)-cell, NK T-cell, and ing p53 and p21 signaling and triggering apoptosis. Impor- dendritic cell functions (19–24). Thalidomide and lenali- tantly, blocking UPS in this manner upstream of the protea- domide have been incorporated into the treatment para- some can overcome bortezomib resistance. digm of newly diagnosed and relapsed multiple myeloma as Inhibitors of aggresome pathway. Recent studies have well as maintenance therapy. Pomalidomide, the more identified the aggresome pathway as an alternative system potent drug in this class, has shown promising results in for polyubiquitylated protein degradation and shown that phase I and II studies and was recently approved for relapsed histone deacetylase 6 (HDAC6) binds to both polyubiqui- multiple myeloma (25–28). Pomalidomide with low-dose tylated proteins and dynein motors, thereby acting to shut- dexamethasone has achieved 30% to 40% durable tle protein complexes to aggresomes (11). We have led both responses even in patients whose multiple myeloma is preclinical studies and clinical trials combining broad type resistant to both lenalidomide and bortezomib, and this 1 and 2 HDAC inhibitors vorinostat or panobinostat to agent is currently under evaluation in combination clinical block aggresomal pathway with the proteasome inhibitor trials with proteasome inhibitors. bortezomib to overcome bortezomib resistance (12, 13). In Monoclonal antibodies. mAb-Based therapies function an international phase III clinical trial, the combination of by stimulating antibody--dependent cell-mediated cytotox- vorinostat and bortezomib was superior to bortezomib icity (ADCC) or complement-dependent cytotoxicity and placebo in relapsed and refractory multiple myeloma, (CDC) mediated by NK or T cells, blocking growth or with overall response rates of 54% versus 41%, respectively survival signaling molecules by inhibiting ligand or its (P < 0.0001). The progression-free survival (PFS) and time binding to receptors, stimulating apoptosis signaling cas- to progression were prolonged in the combination arm cades, and/or specifically delivering chemotherapeutic compared with the bortezomib alone cohort, with PFS HR agents or toxins to multiple myeloma cells (29). Numerous reduction of 23% (P ¼ 0.01). However, the actual PFS mAb-based strategies have been preclinically and clinically difference was only 7.63 versus 6.83 months, owing at least evaluated in multiple myeloma. One of the most promising in part to the side effect profile of diarrhea, fatigue, and mAbs is elotuzumab, which targets CS1, an antigen highly thrombocytopenia attendant to combined therapy. A clin- and uniformly expressed at the gene and protein level in ical grade prototype-selective HDAC6 inhibitor, ACY 1215, multiple myeloma cells of patients (30). Elotuzumab med- has rapidly been translated from the bench to the bedside iates ADCC in preclinical models, and a derived clinical trial and is now under evaluation as a single agent as well as in of single-agent elotuzumab in relapsed refractory multiple combination with bortezomib to achieve dual blockade of myeloma achieved stable disease. Importantly, our labora- proteasomal and aggresomal protein degradation, with a tory studies showed that ADCC activity of elotuzumab more favorable therapeutic index (14). against multiple myeloma cells was enhanced by lenalidomide, which in turn translated to phase I/II trials of lena- Immune manipulations lidomide, elotuzumab, and dexamethasone. Remarkably, Immune dysfunction with decreased humoral and cellu- this combination achieved 82% response in relapsed mul- lar responses and related risk of infection is a hallmark of tiple myeloma, and after a median follow-up of 16.4 multiple myeloma. This suppressed immune function per- months, the median time to progression was not reached mits continued growth of tumor cells. Dysregulation of (31), providing the framework for an ongoing phase III trial various components of T-helper (TH) cells has recently been of lenalidomide, elotuzumab, and dexamethasone versus described, including decreased TH1 responses with IFH-g lenalidomide and dexamethasone in relapsed multiple production, increased suppressor responses by TH2 cells, myeloma. and dysfunctional T-regulatory cells (15), and increased A number of other mAbs targeting multiple myeloma TH17 cells with associated cytokines [interleukin (IL)-17, IL- cells or its bone marrow environment have progressed 21, IL-22, and IL-23], which both promote tumor cell to phase I/II studies. These include daratumumab, a growth and bone disease and suppress immune function humanized mAb targeting CD38 that induces ADCC and (16). Similarly, plasmacytoid dendritic cells are abnormal CDC, modulates enyzymatic activation, and induces in multiple myeloma because they do not trigger normal apoptosis by crosslinking CD38 (32). A preliminary effector cell function as well as promote tumor cell growth phase I/II investigation of this mAb in heavily pretreated and drug resistance (17). Strategies to overcome these multiple myeloma showed clinical benefit in 18 of 29 mechanisms of immune suppression for clinical applica- patients, including 5 partial responses. BT062, an anti- tion include anti–IL-17 monoclonal antibody (mAb), anti- CD138 mAb conjugated to mytansinoid DM4, selectively IL-6 mAb, anti-PD1 mAb, CpG oligonucleotides, and triggered apoptosis in multiple myeloma cells in preclin- immunomodulatory agents (18). ical models (33). In phase I/II trials, preliminary evidence Immunomodulatory agents. Thalidomide, lenalidomide, of clinical benefit has been observed. mAbs targeting and pomalidomide are immunomodulatory agents, which cytokines, including siltuximab targeting IL-6 (34), directly target multiple myeloma cells, abrogate binding of BHQ880 targeting DKK1 (35), tabalumab targeting B-cell

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activating factor (BAFF; ref. 36), and denosumab, a fully cines, tumor-associated antigen-specific protein or peptide- human monoclonal antibody that inhibits receptor acti- based vaccinations are also being investigated in multiple vator of nuclear factor-k B ligand (RANKL; ref. 37), also myeloma. One of the best-studied target antigens is idiotype have promise as treatments of both multiple myeloma protein, the immunoglobulin produced by multiple mye- and related bone disease. Combination of tabalumab and loma cells. Although clinically meaningful immunologic bortezomib has shown interesting activity in a phase I/II responses and antitumor effects after idiotype protein vac- study. The stage of clinical development of additional cination have been reported in lymphoma, direct evidence mAbs in multiple myeloma is shown in Table 1. of clinical benefit in multiple myeloma is lacking (18). Vaccination strategies. On the basis of the success of Other multiple myeloma-associated antigen targets for vac- allogeneic transplantation in achieving long-term disease- cines include Sp17, MAGE-1, NY-ESO, Xbp-1, CD138, free survival as well as graft-versus-multiple myeloma DKK-1, and CS1, which are commonly tested first in the þ responses following donor lymphocyte infusions, other context of HLA-A2 patients (40–46). Moreover, peptide immunotherapeutic approaches are being evaluated to treat cocktails from several antigens have been pooled for vac- multiple myeloma. An emerging focus has been to augment cination to expand the breadth and potency of response autologous anti–multiple myeloma immune responses (47). The task ahead is to evaluate these vaccine approaches using both dendritic cell–based (38) as well as protein and in appropriate clinical settings early in the disease course or peptide-based vaccination approaches. A dendritic cell/ in the setting of minimal residual disease, and to couple multiple myeloma cell fusion vaccination has shown induc- them with strategies to overcome mechanisms of immu- tion of humoral and cellular immune response in patients noparesis (19) as a means to induce more robust clinically after transplant (39), and its clinical benefit will be evalu- significant immune responses. ated in a clinical trial. Anti-PD-1 mAb has also been investigated in clinical trials as a means to restore immune Promising novel targets function and prolong clinical response after transplant. To BET bromodomains. Gene regulation is fundamentally overcome the complexity of cell-based vaccination and to governed by reversible, noncovalent assembly of macro- fulfill the need to produce individual patient-specific vac- molecules. The e-N-acetylation of lysine residues on

Table 1. Monoclonal antibody–based clinical studies in myeloma

Clinical study Target Agent phase Single agent (S)/combination (C) Activin A Sotatercept I/II S BAFF Tabalumab (mAb) I/II S, C (lenalidomide) CD38 Daratumumab I S SAR650984 I S MOR202 I S CD40 Dacetuzumab (SGN-40) Ib S, C (lenalidomide) Lucatumumab (HCD122) I S CD56 huN901-DM1 (C-mAb) I S CD74 Milatuzumab I/II S CD138 BT062 (mAb-DM4) I S CS1 Elotuzumab II/III S, C (lenalidomide, bortezomib) CXCR3 Plerixafor II C (bortezomib) DKK-1 BHQ-880 (mAb) I/II S FGF, PDGF Dovitinib I S HM1.24 anti-HM1.24 (mAb) IGF-1/R CP-751,871 (mAb) I S EM164 (mAb) I S IL-6/R Siltuximab (mAb) II S, C (bortezomib) KIR IPH101 (mAb) I/II S MUC1 AR20.5 (mAb) I/II S RANKL Denosumab (mAb) I/II S TRAIL Apo2L/TRAIL (Apo2 ligand) I S Mapatumumab I/II S VEGF/R Bevacizumab (mAb) II S SU5416 II S Vandetanib (ZD6474) II S

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histone tails (Kac) is associated with an open chromatin recently been evaluated. Btk knockdown confirmed the architecture and transcriptional activation. Context-spe- role of Btk activation in the bone marrow milieu in cific molecular recognition of acetyl-lysine is principally promoting multiple myeloma cell growth, survival, and mediated by bromodomains. Therefore, bromodomain- interaction with other bone marrow stromal compo- containing proteins are of substantial biologic interest, nents, as well as multiple myeloma-induced bone lysis both as components of transcription factor complexes (55). Importantly, an oral and selective Btk inhibitor and determinants of epigenetic memory. The bromodo- ibrutinib blocked RANKL/M-CSF-induced phosphoryla- main and extra-terminal (BET)-family (BRD2, BRD3, tion of Btk and downstream PLCg2inosteoclasts,thereby BRD4, and BRDT) is defined by a common domain abrogating TRAP5b and bone resorption activity, as well architecture comprising 2 N-terminal bromodomains as decreasing secretion of multiple cytokines and chemo- that share a high level of sequence conservation and a kines from osteoclasts and bone marrow stromal cells. It more divergent C-terminal recruitment domain. Recent also blocked multiple myeloma cell growth and survival research has established a compelling rationale for target- triggered by IL-6 or coculture with bone marrow stromal ing bromodomains in cancer (48), in particular, BRD4 in cells or osteoclasts in vitro. In addition, in vivo activity of multiple myeloma (49). BRD4 is a critical mediator of ibrutinib against multiple myeloma cells and multiple transcriptional elongation, recruiting the transcription myeloma cell–induced osteolysis has been shown in the elongation factor complex (P-TEFb). Knockdown of severe combined immunodeficient (SCID)-hu model of BRD4 in proliferating cells leads to G1 arrest and apo- human multiple myeloma in mice. These functional ptosis, associated with decreased expression of genes sequelae of Btk activation mediating osteolysis and important for mitotic progression and survival. The growth of multiple myeloma cells have provided the basis mechanistic link between transcriptional elongation, for ongoing phase I/II clinical trials of ibrutinib in mul- BRD4, and the c-Myc oncogenic transcription factor pro- tiple myeloma. vided the rationale for BRD4 inhibition in multiple myeloma (49). JQ1, the first chemically optimized potent Synergistic combination therapies and selective inhibitor of BET bromodomains, showed The success rate of phase III randomized clinical trials in efficacy in preclinical models of multiple myeloma (50). oncology has been very low, but in multiple myeloma, we Specifically, JQ1 leads to depletion of the c-Myc onco- have informed the design of combination clinical trials protein and downregulation of the c-Myc transcriptional based upon additive or synergistic cytotoxicity, as well as program, leading to cell-cycle arrest and tumor cell senes- on overcoming drug resistance, in preclinical models. For cence both in vitro and in vivo. Clinical trials of BRD4 example, pegylated doxorubicin with bortezomib, based inhibitors therefore represent a new potential therapeutic upon inhibition of DNA-damage repair by bortezomib in modality for multiple myeloma. preclinical studies, showed efficacy in a phase III trial and is MMSET. MMSET is a multiple myeloma oncogene now FDA approved. Enhanced efficacy of immunomodu- identified at the t(4;14) translocation breakpoint present latory drugs thalidomide and lenalidomide with corticos- in approximately 15% of multiple myeloma (51). Micro- teroids in preclinical models provided the framework for array analysis showed that all patients harboring the t(4;14) their clinical evaluation and ultimate FDA approval in rearrangement overexpressed MMSET (52). MMSET con- combination. Recent studies have validated a number of tains several potential functional motifs, including a SET targets the inhibition of which can sensitize or overcome (Suvar 3-9, Enhancer-of-zeste, Trithorax) domain with his- resistance to bortezomib in vitro, including inhibitors of tone methyltransferase activity. Like other SET domain– HDAC (56, 57), aurora kinase A (58), Akt (59), HSP 90 (60, containing proteins, MMSET can methylate histones, there- 61), BAFF (36, 62), and cyclin-dependent kinase 5 (63), and by leading to changes in gene expression. Methylation of combination clinical trials are ongoing. Perhaps, the most histone 3 lysine tail residue 36 is associated with the active combination to date is that of lenalidomide, borte- activation of gene transcription in multiple myeloma (53, zomib, and dexamethasone, which preclinically triggers 54). Overexpression of MMSET in multiple myeloma cells dual apoptotic signaling and clinically can achieve has profound effects on gene expression and cell growth, responses in nearly two thirds of patients whose multiple which requires the enzymatic function of the SET domain. myeloma is resistant to either lenalidomide or bortezomib Because MMSET plays a critical role in pathogenesis of alone (64). Importantly, this combination as initial therapy t(4;14) multiple myeloma, it represents a novel therapeutic in a phase II study has led to a report of 100% overall target amenable to blockade with small molecules. response, with three quarters very good partial responses BTK. Bruton’s tyrosine kinase (Btk), a nonreceptor tyro- and nearly half complete responses, including molecular sine kinase, plays a key role in normal B-cell function complete responses (65). Indeed, we are currently evaluat- through activation of the B-cell antigen receptor signaling ing the role of high-dose melphalan and stem cell trans- pathway. Btk also plays a major role in osteoclastogenesis plantation in the context of this unprecedented extent and and osteoclast maturation by modulating the activity of frequency of response. These studies show rapid translation NFATc1, the major transcriptional factor activated follow- of preclinical leads from the bench to the bedside and ing RANKL stimulation. Its potential role in the multiple clinical trials, which have improved the practice of medicine myeloma cell and its microenvironment has therefore in multiple myeloma.

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Development of personalized medicine in multiple development of resistance, will be needed from the outset to myeloma treat newly diagnosed multiple myeloma. For example, Comprehensive oncogenomic analysis has identified with a backbone of combinations containing proteasome numerous complex genetic and epigenetic alterations in inhibitors, immunomodulatory agents, and steroids, addi- multiple myeloma. Some of these recurrent and highly focal tional agents can be added on the basis of patient-specific amplifications and deletions in the multiple myeloma genomic abnormalities, such as an activated Ras/Raf path- genome have now been identified at an early stage of plasma way, p53 abnormality, MMSET, or specific HDAC upregu- cell disorder (66), including monoclonal gammopathy of lation. Then, maintenance therapies such as lenalidomide undetermined significance and smoldering multiple mye- or newer agents under investigation may prolong response. loma, with further evolution associated with progression to The parallel development of assays for minimal residual active multiple myeloma (67). Importantly, an integrated disease, including PCR for patient-specific immunoglobu- analysis of genomic data has identified candidates resident lin gene rearrangements or the use of multiparameter flow within the regions of genomic alterations predicted to be cytometry, can in turn inform the need for and duration of involved in multiple myeloma pathogenesis and progres- maintenance treatment strategies. Ultimately, prolonged sion. The biologic behavior and clinical outcome in mul- disease-free survival and cure are on the horizon in multiple tiple myeloma are dependent on these molecular deter- myeloma. minants, which are also attractive therapeutic targets. Although FISH-identified t(4;14), t(14;16), and del17p13 Disclosure of Potential Conflicts of Interest have been considered to portend poor prognosis (68), more N.C. Munshi has an ownership interest (including patents) in Oncopep recent single-nucleotide polymorphism array analysis in and is a consultant/advisory board member of Celgene, Millenium, Onyx, and Merck. K.C. Anderson has an ownership interest (including patents) and 192 uniformly treated patients identified amp(1q23.3), is a scientific founder of Acetylon, a scientific founder of Oncopep, and a amp(5q31.3), and del(12p13.31) as the most powerful consultant/advisory board member of Celgene, Millennium, Onyx, and independent adverse prognostic markers (P < 0.0001; Merck. The Editor-in-Chief of Clinical Cancer Research (K.C. Anderson) is an ref. 69). The data obtained from extensive analysis of patient author of this article. In keeping with the AACR’s Editorial Policy, the paper samples with annotated clinical outcome have now pro- was peer reviewed and a member of the AACR’s Publications Committee vided insight into the molecular mechanism of disease identified an editor from another AACR journal to oversee the review process. behavior, helped develop sensitive prognostic models, Authors' Contributions identified novel therapeutic targets, provided the frame- Conception and design: N.C. Munshi, K.C. Anderson work for the development of molecularly based therapies, Development of methodology: N.C. Munshi, K.C. Anderson and eventually will help develop individualized therapy Acquisition of data (provided animals, acquired and managed patients, provided facilities, etc.): K.C. Anderson (70) to improve outcomes with reduced toxicity. Impor- Analysis and interpretation of data (e.g., statistical analysis, biosta- tantly, our study and those of others profiling DNA, mRNA, tistics, computational analysis): N.C. Munshi, K.C. Anderson Writing, review, and/or revision of the manuscript: N.C. Munshi, K.C. microRNA, and spliced RNA (67), as well as proteomics and Anderson whole-genome sequencing (71), have showed remarkable Administrative, technical, or material support (i.e., reporting or orga- complexity in multiple myeloma even at diagnosis, with nizing data, constructing databases): N.C. Munshi, K.C. Anderson further genomic evolution ultimately leading to relapse of disease. It therefore seems, as in the models of childhood Grant Support This work was supported in part by grants from the Veterans Adminis- acute lymphoblastic leukemia and other curable cancers or tration I01–BX001584 and NIH grant RO1-124929 (to N.C. Munshi); NIH infectious diseases, such as tuberculosis and HIV, that Grants P50-100007, PO1-78378, and PO1-155258 (to N.C. Munshi and K. combination therapies will be needed. Specifically, targeted C. Anderson); and NIH Grant RO1-50947 (to K.C. Anderson). combination therapy regimens directed at those genetic Received August 4, 2012; revised February 18, 2013; accepted February 26, abnormalities present, as well as those known to confer 2013; published OnlineFirst March 20, 2013.

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3344 Clin Cancer Res; 19(13) July 1, 2013 Clinical Cancer Research

New Strategies in the Treatment of Multiple Myeloma

Nikhil C. Munshi and Kenneth C. Anderson

Clin Cancer Res 2013;19:3337-3344. Published OnlineFirst March 20, 2013.

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