Abstract Abstract 834 Multiple myeloma (MM) is an incurable bone marrow cancer. Events mediating transformation from the pre-malignant monoclonal gammopathy of undetermined significance (MGUS) to MM is unknown. We analyzed 2 gene expression datasets generated on the Affymetrix U133 platform. The test set consisted of 22 MGUS and 101 MM (GEO Accession GSE6477) and the validation set 50 MGUS and 351 MM (GEO Accession GSE2658 and GSE5900). The gene expression profiles of MM were compared to MGUS using gene-set enrichment analysis. Genes over-expressed in MM were enriched for cell cycle, proliferation and MYC activation gene-sets. We dissected the relationship between MYC and cell cycle, and identified a MYC activation signature dissociated from proliferation. We validated our MYC signature in publicly available mouse and human cell line gene expression dataset (GEO Accession GSE3151 and GSE3158 respectively), showing specific expression of our MYC signature in cell lines forced to expressed MYC but not when over-expressing other oncogene such as E2F, HER2. In these analyses, we noted that tumors with RAS mutation also consistently express this signature. Applying this signature to the test dataset, we showed that MYC is activated in 60% of myeloma but none of MGUS. This pattern is reproduced in an independent validation dataset. In order to validate the hypothesis that RAS mutation may also lead to the MYC activation signature, we correlated RAS mutation with MYC activation as measured by a MYC index calculated from the median expression of genes that constitute the MYC activation signature, and showed that almost all cases with RAS mutation have a high MYC index. Together with samples with very high expression of MYC mRNA corresponding to those with MYC translocations, these 2 mechanisms account for 67% of cases with MYC activation. To further confirm MYC activation, we performed immunohistochemistry using a validated MYC antibody together with CD138 double-staining. We can clearly identify CD138 positive plasma cells with and without nuclear MYC expression and found that nuclear expression of MYC, a marker of MYC activation, correlated strongly with the MYC signature, therefore providing clear evidence that MYC activation is present in majority of newly diagnosed MM but not in MGUS. MYC activation is not very well correlated with proliferation as assessed by the plasma cell labeling index. Among newly diagnosed myeloma patients with plasma cell labeling index less than 1, those with nuclear MYC expression have significantly shorter survival than those without (Median survival 77.7 months versus 37.9 months, log-rank p-value 0.04). Multiple pathways converge on MYC activation, which is a common transforming event in MM associated with poor prognosis. MYC nuclear staining by IHC can be a useful clinical surrogate. Targeting MYC can be a chemoprevention strategy. Disclosures: Fonseca: Amgen: Consultancy; Medtronic: Consultancy; Celgene: Consultancy; Bristol Mayor Squibs: Consultancy; Genzyme: Consultancy; Otsuka: Consultancy.
Abstract Abstract 5132 There is a well- recognized correlation between cancer and aberrant hemostasis. Venous thromboembolism (VTE) in individuals with solid epithelial tumors has been associated with a poor prognosis, with more than three-fold higher risk of early death as compared to cancer patients without thrombosis. The expression of tissue factor (TF), a cell-surface membrane glycoprotein that triggers the activation of coagulation by cancer cells, is one of the main underlying mechanisms linking thrombosis and aggressive tumor behavior. TF is expressed in a variety of solid tumors in association with genetic events affecting oncogenes and tumor suppressor genes. However, the mechanisms of thrombosis in individuals with hematological malignancies may differ from those with solid tumors. We have previously shown that despite the high rate of thrombosis in multiple myeloma, malignant plasma cells only rarely express TF. We sought to determine TF gene (F3) and protein expression in hematological neoplasias. F3 expression profiling was studied on a variety of cell lines established from lymphoid and myeloid neoplasias available at Glaxo Smith Kline (GSK) Cancer Cell Line Genomic Profiling Dataset (https://array.nci.nih.gov/caarray/project/woost-00041). Interestingly, F3 expression was absent in all lymphoid neoplasias studied, in sharp contrast to acute myeloid leukemias (AML) and solid tumors, of which 30 and 90% expressed F3, respectively. Immunohistochemistry (IHC) confirmed the absence of TF protein expression in all indolent and high-grade B-cell lymphomas (99 patients, including germinal center and activated B-cell phenotype diffuse large B-cell lymphomas) and in all T-cell lymphomas/leukemias (20 patients) studied. IHC for TF was also negative in AML (11 patients) but positive in representative solid tumors (breast, pancreas, prostate), except for renal cell carcinoma which has been previously shown to lack TF. We propose that the pathogenesis of VTE associated with hematological neoplasias differs from that of solid tumors. Though TF from non-neoplastic cell sources may still be important for the prothrombotic state often seen in these patients, we show there is no evidence for a role of tumor-derived TF in the development of DVT, nor in neoplastic behavior. Thus, treatments directed against TF may not impact on prognosis in lymphoid, and non TF-expressing myeloid neoplasias. Disclosures: No relevant conflicts of interest to declare.
Impact of FISH and Cytogenetics On Overall and Event Free Survival in Myeloma: An IMWG Analysis of 9,897 Patients.
Abstract Abstract 743 Background There has been considerable recent focus upon the molecular classification of myeloma. However, the prognostic impact of molecular changes has mostly been assessed from small and/or incomplete studies from single institutions or groups. There has been no large scale analysis of molecular features linked to ISS stage. Methods In order to clarify the overall impact of molecular changes we undertook a collective analysis of 9,897 patients through the International Myeloma Working Group (IMWG). Within this population 2,295 patients had presence of cytogenetic abnormalities (Any CA); 1,713 hypodiploidy; 1,673 hyperdiploidy; 2,309 cytogenetic deletion 13; 3,226 deletion 13 by FISH; 1,573 FISH t(4;14); 1,486 FISH del p17; 1, 683 FISH t(11:14); and 366 FISH t(4;16). Enrolled patients had complete clinical and treatment details available including baseline standard prognostic factors, ISS stage, as well as both progression free survival (PFS) and overall survival (OS) information. Data came from 14 sites: 3 from the US and the remainder from Europe, Asia, and Latin America as for the ISS staging system analyses. Univariate and multivariate analyses were performed. Results Each of the known adverse molecular features had a negative impact upon both PFS and OS (p=002 - <0.0001). Among the deleterious FISH abnormalities the t(4;14) abnormality was the most highly correlated with poorer outcomes by PFS: 4 year estimate: 32% vs. 60% (p<0.0001). The t(4;14) abnormality combined with ISS Stage also significantly enhanced predictive capability: ISS Stage I without t(4;14) OS 81% @ 4 years; ISS Stage III with t(4;14) OS 22% @ 4 years (P<0.0001) [Figure 1]. The best outcomes were for ISS Stage I in the presence of t(11;14): OS 89% @ 4 years. Absence of any one adverse feature correlated with 80-81% OS @ 4 years for Stage I. Presence of any one adverse feature had a more variable impact and correlated with 22%-40% OS at 4 years for Stage III. In univariate correlations the most predictive correlations with OS were presence of Any CA, t(4;14), 17p-, hypodiploidy, cytogenetic 13q- with R2 values of 6.9%, 4.5%, 4.1% and 3.8% respectively. In multivariate analyses, ISS stage provided the best predictions: R2 values = 13.3%. The added contributions from molecular features were: t(4;14) 3.8%; cytogenetic 13q- 2.9%; Any CA 2.3%; and 17p- 1.0%. The maximum total R2 for OS was 22%. Conclusions This large multicenter analysis confirms the correlations between abnormal molecular findings and outcomes. Combinations with ISS Stage provide the best predictive capability. Presence of Any CA, t(4;14), 17p-, hypodiploidy and cytogenetic 13q- contribute to poorer outcomes by ISS stage. The presence of hyperdiploidy and/or t(11;14) contribute to better outcomes. There is thus validation of prior molecular studies related to prognosis utilizing this large IMWG database. Disclosures: No relevant conflicts of interest to declare.
Abstract Abstract SCI-4 Introduction Plasma cell leukemia (PCL) represents an aggressive variant of multiple myeloma (MM) characterized by the presence of large number of circulating plasma cells (PC) in the peripheral blood. While some boundaries have been defined to establish a diagnosis of PCL (PC in the peripheral blood greater than 2×109/l-1 or 20% of leukocytes being plasma cells), these values are artificial, and most cases of PCL show extreme numbers of circulating plasma cells. PCL is part of a spectrum of the PC neoplasms where increasing numbers of circulating PC identify aggressive MM, yet many cases do not satisfy criteria for PCL. Historically PLC has been divided into “Primary PCL” (pPCL) when it represents the initial manifestation of a PC neoplasm, and “Secondary PCL”, or MM with leukemic transformation (MM-LT). Both entities share biologic and clinical similarities as aggressive variants of MM, but the latter represents a fulminant PC neoplasm with historic survival of only 1-2 months. In contrast, pPCL, while nevertheless aggressive, often will respond to induction treatment and can occasionally result in a durable response. Biology Because of the rarity of PCL (1% or less of all MM) the genetic description of the disease has been limited by lack of material for study. Nevertheless most PCL cases harbor IgH translocations (87% of pPCL and 82% in MM-LT). In particularly the t(11;14)(q13;q32) is common; observed in 35 to 70% of cases of pPCL. In contrast MM-LT contains most other genetic aberrations associated with MM pathogenesis, including the more benign genetic variants of the disease (e.g. hyperdiploid MM), and these cells are presumed to have acquired additional genetic features resulting in aggressive clonal proliferation and expansion. When karyotypes are informative (frequently in PCL) they are almost always non-hyperdiploid variant, mostly hypodiploid. Rare cases of hyperdiploid karyotypes have been observed in association with MM-LT. Monoallelic deletions of 17p13.1, at the TP53 locus and similar to those seen in MM, can be detected in 50% of pPCL and 75% of MM-LT. While mutations of TP53 area rare in MM they are common in PCL (24%), contributing to a substantial overall prevalence of TP53 inactivation of 56% in pPCL and 83% in MM-LT. Furthermore, we found the upstream tumor suppressor p14ARF, whose product directly binds MDM2 enhancing p53 function, to be inactivated by methylation in 29% of MM-LT. MYC abnormalities are only observed in 15% of cases and the distribution of chromosome 13 deletion/monosomy is similar to what would be expected for the corresponding karyotypic aberrations (85% in the hypodiploid pPCL and 50% in MM-LT). Treatment and future directions Historically the treatment of PCL has been unsatisfactory with few patients achieving durable remissions, and most dying within weeks to months after diagnosis. The impact of more intensive regimens (including autologous and allogeneic stem cell transplant) and of novel agents such as bortezomib and lenalidomide are not known. However, early data suggest, that the historic survival rates of pPCL (∼12 months) and MM-LT (∼1-2 months) will be improved by the aforementioned interventions. It is likely that with increasing survival of MM patients, MM-LT will become an increasingly common and difficult problem to manage. Disclosures Fonseca: Various: CME lectures; Halozyme: Consultancy; BMS: Consultancy; Medtronic: Consultancy; AMGEN: Consultancy. Off Label Use: Multiple agents to be used for the treatment of plasma cell leukemia. No agents are specifically approved for this indication although this is a variant of myeloma.
Evidence for Cytogenetic and Fluorescence in Situ Hybridization (FISH) Risk Stratification of Newly Diagnosed Multiple Myeloma in the Era of Novel Therapies.
Abstract Abstract 1802 Poster Board I-828 Background Heterogeneity in multiple myeloma (MM) leads to disparate outcomes with a wide variation in overall survival (OS). Based upon the evidence predominantly gathered from newly diagnosed patients treated with standard chemotherapy and/or transplantation, the current Mayo (mSMART) prognostic model uses a combination of metaphase cytogenetics, fluorescence in-situ hybridization (FISH) and plasma cell labeling index (PCLI) for risk-stratification at diagnosis of MM. The objective of our study was to evaluate the significance of this stratification model in the era of novel therapies, and to assess the independent prognostic value of each of the components in the model. Methods Data were abstracted from a cohort of 1556 consecutive patients with MM who presented to our institution between January 1999 and March 2009 within ninety days of diagnosis of MM A total of three hundred and eighty six patients had been evaluated with conventional cytogenetics near diagnosis in addition to interphase FISH. Out of this cohort, three hundred and sixty six patients had availability of all the three tests, including the slide-based PCLI. High-risk MM was defined as presence of any one or more of the following: cytogenetics: hypodiploidy, monosomy of chromosome 13 or deletion 13q ; FISH: deletion of p53 (locus 17p13) or immunoglobulin heavy chain (IgH) translocations, t(4;14) (p16.3;q32) or t(14;16)(q32;q23); PCLI ≥3%. Survival estimates were created using the Kaplan-Meier method and compared by log-rank tests. The impact of each of the three tests was assessed by a multivariate (MV) analysis using Cox proportional hazards model. Results The median OS of the cohort of 366 patients was 65 months from presentation. One hundred and twelve (31%) patients were deemed high risk by any one or more of the three tests: Metaphase cytogenetics, FISH or PCLI (current mSMART definition of high-risk MM). The median OS of high risk patients was 52 months versus 71 months for standard-risk (P=0.007). We then studied the prognostic value of the three tests separately. Patients classified as high risk by FISH had a median OS of 35 months versus 65 months for the standard risk, HR= 2.3, P<0.001. Similarly, cytogenetics alone was also able to classify patients into high and standard risk with a comparable HR of 2.1 (P=0.008, median survival 37 vs. 64 months). In contrast, PCLI did not have a significant prognostic value (HR =1.41, P=0.32). This was confirmed on multivariate analysis in a model that included all 3 tests. FISH (HR=2.36, P=0.001) and cytogenetics (HR=1.99; P=0.017) emerged as independent determinants of prognosis in the multivariable analysis, while PCLI (HR=1.03, P=0.93) did not provide additional prognostic value. We then examined whether the prognostic value of FISH contributed additionally in patients classified into high and standard risk by conventional cytogenetics, and vice versa. Those classified as high risk by cytogenetics (n=44, 11 %), were further categorized into 2 groups by additional prognostic information obtained by FISH (median survival 18 vs. 52 months; P=0.005). Similarly, those classified as standard risk by cytogenetics (n=342, 89 %), were further categorized into 2 groups (median survival 52 vs. 71 months; P=0.017) by additional FISH-based stratification. Similarly, high-risk patients defined by FISH (n=65, 17 %) were further classified into 2 groups with significant difference in median OS (18 vs. 52 months, P=0.004), based on the presence or absence of high-risk features on cytogenetics. In contrast, no additional prognostic information was gained by cytogenetics in patients who were stratified as standard risk by FISH alone (n=321, 83%). Conclusion Our study validates high risk features defined by FISH and conventional cytogenetics in the mSMART risk stratification model among patients treated after the introduction of novel therapies. Either test identifies a high risk cohort with a hazard ratio of approximately 2 (median survival ∼37 versus ∼65 months). In patients known to have high risk disease by one of the two tests, knowledge of the other appears to add additional prognostic value. Disclosures Fonseca: Amgen, BMS, Celgene, Otsuka, Genzyme and Medtronic: Consultancy. Gertz:celgene, millennium: Honoraria. Dispenzieri:celgene: Research Funding. Kumar:celgene, genzyme, millennium, novartis, bayer: Research Funding; genzyme: Membership on an entity's Board of Directors or advisory committees.
A Comprehensive High-Resolution Genomic Analysis of Primary Central Nervous System Lymphomas Shows a Highly Complex Karyotype Characterized by Abnormalities Affecting Multiple Genes Involved in Critical Pathways Associated with Lymphocyte Maturation and Su
Abstract Abstract 4637 Primary central nervous system lymphoma (PCNSL) is an aggressive form of extra-nodal, high-grade, non-Hodgkin B-cell neoplasm. It originates in the brain, leptomeninges, spinal cord or eyes and typically remains confined to the CNS. Further immunophenotypic characterization has revealed that these tumors have overlapping features of germinal center and activated B-cell differentiation. Although the cells of origin are lymphocytes, PCNSL should be considered a brain tumor because its therapeutic challenges resemble those of other brain tumors. Regarding the molecular pathogenesis of PCNSL, there is significantly less information in comparison with systemic lymphomas. The aim of this study was to perform a comprehensive high-resolution genomic analysis in a cohort of PCNSL cases to better characterize the disease at chromosomal and gene level. Copy-number abnormalities were analyzed in seven PCNSL by array-based comparative genomic hybridization (aCGH) using SurePrint G3 (1 million probes, ∼4 Kb resolution) microarray (Agilent). Overall, PCNSL cases were characterized by highly complex genomes with a median of 23 copy-number abnormalities per patient (range 16-49). The whole genomic regions affected in abnormalities correspond to areas between 3% and 29% of the human genome. Globally, 43 chromosomal regions were affected in a recurrent fashion (24 areas involved in recurrent deletions and 19 in copy-number gains). Gain of 12q12-q24.33 and losses of 9p21.3 and 6q were the most common abnormalities found in 71% patients each (5 out of 7). There was not a unique deleted region on 6q to all patients, with 6q14.1-q14.3, 6q16.3-q22.2 and 6q25.3-q26 losses being found in 4 out of 5 cases with 6q deletions. None of these regions include PTPRK, which has been previously proposed as a potential modulator of PCNSL progression. CDKN2A was the sole gene included in all cases with 9p21.3, being biallelically deleted in two out of 5 cases. Minimal deleted genes were also delineated in 3p21.1 (minimal affected area of 0.03Mb) and 3q26.32 (0.27Mb) in 44% of cases each. Those regions included PRKCD (inhibits B-cell growth through transcriptional regulation of IL-6) and TBL1XR1 (corepressor of nuclear hormone receptor), respectively. Overall, a total of 22 genes were included in homozygous deletions in at least one case. Besides CDKN2A (cell cycle), other genes of interest associated with the development and activation of T cells (TOX, CD58) were biallelically affected. Focal monoallelic deletions affecting negative regulators of the NFkB signaling pathway (MAP4K1, TANK, TAX1BP1, TRIB3), cell cycle (RB1) and immune-cell regulation (SIRPB1, CBLB, NFATC2) were also identified. Of interest, no copy-number abnormalities were identified affecting TP53 in any patient. Several chromosomal breakpoints were identified inside genes that encodes transcription factors previously identified as being part of fusion protein in other hematological malignancies (FOXP1, ETV6 and NCOA2) thus suggesting the potential existence of fusion proteins including these genes. Cytogenetic and genetic approaches are being currently used to validate this hypothesis. This is the first study characterizing a cohort of PCNSL cases by using this comprehensive high-resolution approach. Regarding the small number of cases analyzed so far, we can confirm the existence of a highly complex genome, mainly characterized by abnormalities affecting a plethora of genes involved in lymphocyte development, activation and NF-kB signaling pathways regulation. Molecular analyses are ongoing to validate these findings in a larger cohort of PCNSL patients. Disclosures: Fonseca: Otsuka: Consultancy; BMS: Consultancy; Amgen: Consultancy; Medtronic : Consultancy; Genzyme: Consultancy.
Activity of Single Agent Drugs in Phase I and II Trials Best Predicts Future Clinical Utility in Multiple Myeloma
Abstract Abstract 4034 Through literature review we identified 376 pre-clinical studies in which a small molecule or antibody has been demonstrated to be cytotoxic to multiple myeloma (MM) cells either as cell lines, primary tumor samples or in mouse models. Indeed it seems there is no limit to the number of compounds that are cytotoxic to MM cell lines at high enough concentration. Since the pipeline to clinical trials is then large the utility of such assays in predicting future clinical value is debatable. We therefore sought to examine the utility of applying very early Phase I or Phase II trial experiences to predict for future clinical adoption. Using Pubmed, ASCO, ASH, EHA and IMWG abstracts we identified 117 drugs explored as single agents in 211 early stage clinical MM trials between 1961 and 2012 involving 7,166 patients. As definitions have changed over time, our analysis used partial responses (PR) or better as a response. When multiple trials were reported with a single drug, the average and the highest response rate for that agent was identified. Results were considered regardless of whether single or multi center trial, elderly or younger patients, stage of disease, targeted or non targeted therapy. High dose therapies requiring autologous stem cell support (eg. melphalan and etoposide), trials with less then 5 patients (e.g. siltuximab) or trials with concomitant steroid application which obscure single agent activity (e.g. pomalidomide, marizomib or daratumumab) were excluded in the analysis. Results: 17 drugs (14.5%) showed a best result of PR in more than 20% of patients, but when average response across all reported trials is considered, doxorubicin, arsenic trioxide and idarubicin drop out leaving 14 active drugs. Twelve drugs (10.3%) report as a best result PR in 10–20% of patients. 88 drugs (75.2%) reported a PR response in less than 10% of patients, 68 of which (58.1%) had no reported activity. A striking finding of our study is that all drugs approved for, or commonly used in clinical practice (prednisone, dexamethasone, cyclophosphamide, melphalan, bendamustine, thalidomide, lenalidomide, bortezomib, carfilzomib) have an average single agent PR response of at least 20%. Pomalidomide, although not approved, meets this threshold in Phase I testing. Older agents including teniposide, fotemustine, paclitaxel, and interferon also appear active by this criteria but have fallen from favor or were never adopted due to perceived toxicity. Of note, a number of newer agents which are in, or which recently completed Phase 3 testing, such MLN9708, elotuzumab, panobinostat, vorinostat or perifosine show little single agent activity. A weakness in this approach is that changes in measurement of response over time might bias the results, especially in favor of older studies. Furthermore, the chance of responding to a new drug has likely slowly declined as therapies have improved and patients have entered such trials at increasingly late stages of disease. It also does not rule out the possibility of synergistic activity or clinical benefit from a cytostatic drug. Nevertheless, our analysis suggests that a cut off of 20% single agent partial response activity averaged across all trials with that agent is highly predictive of future clinical success. If best reported response over 20% is considered no drug except vincristine has yet reached the clinic and has subsequently fallen from favor. Thus only drugs with 20% PR activity are in widespread use and thus this benchmark provides a framework for guiding choice of drugs for late stage clinical testing. Disclosures: Jimenez-Zepeda: MMRF: Research Funding; Jansenn Ortho: Honoraria. Fonseca:Onyx: Consultancy, Research Funding; Cylene: Research Funding; Medtronic: Consultancy; Otsuka: Consultancy; Celgene: Consultancy; Genzyme: Consultancy; BMS: Consultancy; Lilly: Consultancy; Binding Site: Consultancy; Millenium: Consultancy; AMGEN: Consultancy; Mayo Clinic: Patents & Royalties. Stewart:Millenium: Consultancy, Honoraria, Research Funding; Onyx: Consultancy; Celgene: Consultancy.
Cereblon Expression Predicts Response, Progression Free and Overall Survival After Pomalidomide and Dexamethasone Therapy in Multiple Myeloma
Abstract Abstract 194 Background: Immunomodulatory drugs (IMiDs) are key components of treatment for hematologic malignancies, especially multiple myeloma (MM). Recently, we demonstrated that CRBN expression is the major mediator of IMiD action operating at least in part via interferon regulatory factor 4 (IRF4), however the clinical significance of this finding remains unclear. Methods: To better understand clinical impact, we retrospectively reviewed 148 MM patients whose tumor cells were tested for CRBN expression by Gene Expression Profiling (GEP) prior to treatment with an IMiD containing therapy. Results: GEP studies show no significant differences in CRBN expression between MGUS, smoldering MM (SMM), untreated symptomatic MM and normal plasma cells. However, differences were observed between MM cell lines of varying drug sensitivity to IMiDs and between other B-cell Neoplasia (eg low grade lymphoma has higher levels). Within the genetic subtypes of MM, levels were significantly higher for hyperdiploid patients (median 1.26) as opposed to significantly lower levels for TC class D2 (median 0.76) and average for the 4p16 (median 0.97). We next screened the University of Arkansas Medical School (UAMS) GEP database of MM patients treated with combination therapies and did not find significant correlation between CRBN expression and survival in this multi-agent regimen. We then focused on patients that received only single agent IMiD therapy with low dose dexamethasone. Review of the twelve lowest expressing patients demonstrated a lack of response to IMiDs in any patient. Finally we analyzed 53 relapsed or relapsed/refractory patients treated homogeneously in a study with pomalidomide 2–4mg daily and weekly dexamethasone 40mg. CRBN levels were assessed prior to therapy initiation. Response rates varied significantly based on gene expression level. The percentage of patients that demonstrated at least a partial response was 0% for CRBN <0.81, 19% for CRBN expression of 0.81–0.90, and 33% for CBN expression >0.9. Significant differences in PFS (3.0 months vs. 8.9 months, p = 0.0006) and in OS (9.1 months vs. 27.2 months, p = 0.01) were observed when the lowest quartile of CRBN expression was compared to the top three quartiles. Values used for the cut offs are as follows: (25%: 0.889687; 50%: 1.026542, 75%: 1.211133). While this study demonstrates a positive correlation between CRBN expression and response to pomalidomide and dexamethasone, an important caveat with respect to PFS and OS is that CRBN mRNA level is primarily a reflection of the number of copies of CRBN. Since focal deletions are uncommon, this mostly reflects chromosome 3p copy number. Since trisomy 3 is common in hyperdiploid, good prognosis disease, CRBN not only is required for IMiD function but higher levels also serve as a surrogate for low risk disease. Optimal gene expression cut offs for survival were determined using the Contal and O'Quigley method. The optimal cut point for PFS was 1.18443 and for OS was 1.17816. Conclusion: In summary, this study demonstrates, for the first time, a clinical correlation between CRBN expression and response to IMiD and dexamethasone therapy. CRBN expression is also predictive of survival outcomes and when quantified prior to therapy could potentially be utilized as a predictive biomarker for response to an IMiD based treatment. Disclosures: Stewart: Celgene: Consultancy, Honoraria.
HOXA9 Is a Novel Therapeutic Target in Multiple Myeloma.
Abstract Abstract 832 We hypothesized that new therapeutic targets for multiple myeloma (MM) could be discovered through the integrative computational analysis of genomic data. Accordingly, we generated gene expression profiling and copy number data on 250 clinically-annotated MM patient samples. Utilizing an outlier statistical approach, we identified HOXA9 as the top candidate gene for further investigation. HOXA9 expression was particularly high in patients lacking canonical MM chromosomal translocations, and allele-specific expression analysis suggested that this overexpression was mono-allelic. Indeed, focal copy number amplifications at the HOXA locus were observed in some patients. Outlier HOXA9 expression was further validated in both a collection of 52 MM cell lines and 414 primary patient samples previously described. To further verify the aberrant expression of HOXA9 in MM, we performed quantitative RT-PCR, which confirmed expression in all MM patients and cell lines tested, with high-level expression in a subset. To further investigate the mechanism of aberrant HOXA9 expression, we interrogated the pattern of histone modification at the HOXA locus because HOXA gene expression is particularly regulated by such chromatin marks. Accordingly, immunoprecipitation studies showed an aberrantly low level of histone 3 lysine 27 trimethylation marks (H3K27me3) at the HOXA9 locus. H3K27me3 modification is normally associated with silencing of HOXA9 in normal B-cell development. As such, it appears likely that the aberrant expression of HOXA9 in MM is due at least in part to defects in histone modification at this locus. To determine the functional consequences of HOXA9 expression in MM, we performed RNAi-mediated knock-down experiments in MM cell lines. Seven independent HOXA9 shRNAs that diminished HOXA9 expression resulted in growth inhibition of 12/14 MM cell lines tested. Taken together, these experiments indicate that HOXA9 is essential for survival of MM cells, and that the mechanism of HOXA9 expression relates to aberrant histone modification at the HOXA9 locus. The data thus suggest that HOXA9 is an attractive new therapeutic target for MM. Disclosures: No relevant conflicts of interest to declare.
Tolerance and Response to Initial Systemic Therapy In Older Patients with Multiple Myeloma (MM): Observations From 276 Unselected Recent Cases In the Practices of US-Based Medical Oncologists (MOs)
Abstract Abstract 1516 Background: MM is generally considered incurable, but the rapid integration of IMiDs.. and proteasome inhibitors into systemic anticancer treatment (SAT) has resulted in clinically important improvements in response rates, disease control and overall survival. A number of factors — including age and comorbidities — influence selection of an initial SAT and whether autologous stem cell transplant (ASCT) is planned. A paucity of information exists on selection of specific SATs for patients in different age groups and resultant outcomes. We attempted to address this issue by aggregating and examining clinical information on individual patients receiving initial treatment for MM. Methods: US community-based MOs were recruited from a database of past participants in our CME activities to provide anonymous information on the presenting symptoms, diagnostic workup, treatment selection, side effects and clinical antitumor response for all patients in their practices with a new diagnosis of MM since January 1, 2008. Modest, per-patient honoraria were provided to each MO for this work. Results: From April 14 to July 9, 2010, 43 MOs entered a total of 276 cases of MM into a web-based data bank (minimum 1 case, maximum 14, median 6). 54% of the patients were men. The median age was 68, with 34% under age 65, 36% from 65 to 74 and 30% age 75 or older. 88% of patients had their tumors evaluated by FISH and/or metaphase cytogenetics. 73% of the evaluated specimens were considered to be “standard risk” and 27% were determined to be “poor risk.” 67% of patients were considered very or moderately symptomatic from the disease at the time treatment was initiated (Table 1), and similar fractions of patients presented with various levels of symptomology across the three age groups. 128 patients (46%) were deemed eligible for ASCT (maximum age 78), and 59 of these patients had already received ASCT after induction treatment. The median age of patients eligible for ASCT was 62, and the most common induction SATs for these patients were Rd or RD (29%), RVD (26%) and VD (23%). The median age of patients considered ineligible for transplant was 76.5, and the most common induction SATs were VD (22%) Rd or RD (21%) MPT (17%) and MPV (17%). Overall, these treatments resulted in CR and PR rates of 22% and 64% respectively, and “things went very well with expected or fewer toxicities” in 38% and minor or moderate toxicity in 44%. These outcomes are similar to what has been reported in published trial data from randomized Phase III studies of these regimens. No major differences were observed in reported levels of efficacy and side effects among the three age groups (Table 1). Conclusions: This unselected case series produced, in a rapid manner, useful information addressing a variety of clinical issues in newly diagnosed MM, including the impact of age and transplant status on treatment selection and outcomes. These data suggest that MOs are able to individualize SATs for older patients and match the short-term outcomes of the therapies they select for younger patients. This risk-benefit differential is of particular palliative importance as these data demonstrate that at diagnosis most patients present with tumor-related symptoms. Additional work of this kind is needed to better understand how physicians adjust doses and schedules of SATs to prevent and ameliorate toxicity, particularly in older patients. Disclosures: Lonial: Bristo-Myers Squibb: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene Corporation: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Millenium Pharmaceuticals Inc: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis Pharmaceuticals: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding. Anderson:Celgene Corporation: Consultancy, Membership on an entity's Board of Directors or advisory committees; Millenium Pharmaceuticals Inc: Consultancy, Membership on an entity's Board of Directors or advisory committees; Novartis Pharmaceuticals Corporation: Consultancy, Membership on an entity's Board of Directors or advisory committees; Onxy Pharmaceuticals Inc: Consultancy, Membership on an entity's Board of Directors or advisory committees. Fonseca:Amgen Inc: Consultancy; Bristol-Myers Squibb: Consultancy; Celgene Corporation: Consultancy, Research Funding; Genzyme Corporation: Consultancy; Medtronic Inc: Consultancy; Otsuka Pharmaceutical Co Ltd: Consultancy; Onyx Pharmaceuticals: Research Funding.