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Graft versus host disease (GVHD) commonly induces pathological damage in peripheral target organs such as the skin, liver and gastrointestinal tract leading to well characterized organ-specific clinical manifestations. A number of studies, however, have shown that patients with GVHD can also have behavioral and mood alterations that can affect overall cognitive function and lead to significant impairments in quality of life. The extent to which GVHD contributes to cognitive dysfunction and induces inflammation within the central nervous system (CNS), however, has not been critically examined. To address this question, we conducted studies using two well-defined murine GVHD models [C57BL/6(H-2b)→Balb/c (H-2d) and B10.BR(H-2k)→B6 (H-2b)]. We observed that there was a significant increase in the number of donor-derived CD4+ and CD8+ T cells in the brains of GVHD recipients early (days 7 -14) and late (day 42) post transplantation compared to BM controls. Histological studies revealed activated microglial cells and CD3+ T cell infiltration in the periventricular regions of brains in GVHD recipients that were not present in BM animals. Real time q-PCR analysis also demonstrated significant increases in IFN-γ, TNF-α, and IL-6 mRNA expression indicative of a proinflammatory state. Notably, GVHD animals exhibited behavioral changes in the forced swim test and elevated plus maze which are validated assays of stress coping and anxiety, respectively. Since IL-6, in particular, plays a pivotal role in GVHD pathogenesis in murine models and humans, we examined whether blockade of IL-6 signaling altered neuroinflammation. Animals treated with an anti-IL-6R antibody had a significant reduction in the number of donor-derived CD4+ and CD8+T cells in the brain compared to isotype control-treated mice. Anti-IL-6R treatment of GVHD mice also resulted in significant reductions in IFN-γ, TNF-α, and IL-6 mRNA and normalized behavior in the forced swim test, indicative of a decreased inflammatory response. Since IL-6 is produced by a wide variety of cells, including microglial and T cells, both donor and recipient cells have the potential to modulate GVHD severity within the CNS. To define whether donor or host IL-6 production was most critical for inducing neuroinflammation, experiments were conducted employing IL-6-/- mice as either donors or recipients. Whereas the absence of IL-6 in donor-derived cells had no impact on the degree of inflammation within the CNS, recipient animals that lacked IL-6 had a significant decrease in the number of donor-derived T cells which accumulated in the brain as well as a marked reduction in inflammatory cytokines, indicating that host IL-6 production was critical. To define the downstream pathways of IL-6-mediated CNS inflammation, we examined the role of indoleamine 2,3-dioxygenase (IDO) since IL-6 has been shown to upregulate IDO-1 expression under inflammatory conditions. We observed that IDO-1 mRNA levels were significantly increased in the brains of GVHD animals, and that blockade of IL-6 signaling resulted in a marked decrease in IDO mRNA levels. Additionally, transplantation studies using IDO-/- mice revealed that host, but not donor, IDO production was required for maximal inflammatory effects. Serotoninergic projections to the prefrontal cortex (PFC), in particular, are sensitive to inflammation and contribute to stress coping behavior. Therefore, to further interrogate this pathway, we performed quantitative mass spectrometry of brain extracts from the PFC. We found that tryptophan and 5HT concentrations were not different between BM and GVHD groups. However, there was an increase in the IDO product, kynurenic acid, in GVHD recipients consistent with an increase in brain IDO expression. To provide additional support for the premise that IL-6 effects were mediated through the IDO pathway, recipient mice were treated with either 1-methyltryptophan (1-MT), a completive inhibitor of IDO, or a vehicle control. GVHD mice treated with 1-MT had decreased accumulation of T cells in the brain and normal behavior in the forced swim test, demonstrating that inhibition of IDO abrogated CNS inflammation and behavioral changes in the presence of intact IL-6 signaling. In summary, these studies demonstrate that host IL-6 and IDO regulate inflammation and adversely impact behavioral function within the brain during GVHD through the tryptophan metabolic pathway. Disclosures No relevant conflicts of interest to declare.

Intra-tumoral heterogeneity (ITH) is increasingly viewed as the Achilles heel of treatment failure in malignant disease including multiple myeloma (MM). Most MM patients harbor focal lesions (FL) that are recognized on MRI long before bone destruction is detectable by conventional X-ray examination. Serial MRI examinations show that eventually 60% of patients will achieve resolution of FL (MRI-CR). However, this will lag behind the onset of a clinical CR by 18 to 24 months, thus attesting to the biological differences between FL and diffuse MM growth patterns. Consequently, we performed concurrent gene expression profiling (GEP) analyses of plasma cells (PC) from both random bone marrow (RBM) via iliac crest and FL. Our primary aims were to first compare the molecular profiles of FL vs. RBM, second to determine if ITH existed (as defined molecular subgroup and risk), and finally to investigate if the bone marrow micro-environment (ME) contained a biologically interesting signature. A total of 176 patients were available for this study with a breakdown of: TT3 (n=23), TT4 for low-risk (n=131) and TT5 for high-risk MM (n=22). Regarding the molecular analyses of PCs, GEP-based risk (GEP-70, GEP-5) and molecular subgroup correspondence were examined for commonalties and differences between RBM and FL. A “filtering” approach for ME genes was also developed and bone marrow biopsy (BMBx) GEP data derived from this method is under analysis. PC risk correspondence between FL and RBM was 86% for GEP70 and 88% for the GEP5 model. Additionally, 82% had a molecular subgroup concordance, however, they did differ among subgroups (p=0.020) by Fisher's Exact Test. A lower concordance was noted in the CD2, LB, and PR subgroups (67%, 69%, 73%, respectively). GEP70 and GEP5 risk concordance between RBM and FL samples by molecular subgroup was also examined. The overall correlation coefficients were 0.619 (GEP70) and 0.597 (GEP5). The best correspondence was noted for CD1, MF and PR subgroups especially for the GEP5 model. HY, LB and MS showed intermediate correlations, while CD2 fared worst with values of only 0.322 for GEP70 and 0.267 for GEP5 model. Figure 1 portrays these data in more detail for the GEP70 and GEP5 models. Good correlations were noted between RBM and FL based risk scores in case of molecular subgroup concordance (left panels) in both GEP5 and GEP70 risk models, whereas considerable scatter existed in case of subgroup discordance (right panels). The clinical implications in TT4 regarding RBM and FL derived risk and molecular subgroup information, viewed in the context of standard prognostic baseline variables are portrayed in Table 1. High B2M levels at both cut-points imparted inferior OS and PFS as did low hemoglobin. Although present in 42% of patients, cytogenetic abnormalities (CA) did not affect outcomes. FL-based GEP5-defined high-risk designation conferred poor OS and PFS. B2M>5.5mg/L and FL-derived GEP5 high-risk MM, pertaining to 29% and 11% of patients, survived the multivariate model for both OS and PFS. Next, in examining PC-GEP differences among RBM and FL sites, 199 gene probes were identified with a false discovery rate (FDR) of 1x10-6. Additionally, 55 of the 199 belong to four molecular networks of inter related genes associated with: lipid metabolism, cellular movement, growth and proliferation, and cell-to-cell interactions. Multivariate analysis identified the GEP5 high risk designation of focal lesion PCs to be significantly prognostic with a HR=3.73 (p=0.023).Table 1Cox regression analysis of variables linked to overall and progression-free survival in TT4.Overall SurvivalProgression-Free SurvivalVariablen/N (%)HR (95% CI)P-valueHR (95% CI)P-valueMultivariateB2M > 5.5 mg/L38/130 (29%)3.71 (1.49, 9.22)0.0053.84 (1.58, 9.31)0.003FL GEP5 High Risk14/130 (11%)3.68 (1.19, 11.41)0.0243.73 (1.20, 11.62)0.023HR- Hazard Ratio, 95% CI- 95% Confidence Interval, P-value from Wald Chi-Square Test in Cox RegressionNS2- Multivariate results not statistically significant at 0.05 level. All univariate p-values reported regardless of significance.Multivariate model uses stepwise selection with entry level 0.1 and variable remains if meets the 0.05 level.A multivariate p-value greater than 0.05 indicates variable forced into model with significant variables chosen using stepwise selection. Disclosures: No relevant conflicts of interest to declare.

It is becoming more evident that the bone marrow micro-environment (ME) plays an important role in MM development, progression and treatment response. Studies of the bone ME have largely been limited to in-vitro differentiated cellular subsets. Removing the cells from the from their physiologic cellular environment and manipulating them over an extended period inducing artificial changes results in a significant bias and thus severely limits the applicability of conclusion drawn from those systems to the primary unaltered bone marrow. In order to identify differences between the bone marrow ME of healthy donors and patients with MM we subjected whole BMBx from 378 untreated MM patients and 48 NL subjects, which had been snap frozen immediately after they were taken from the patients, to GEP analysis. Since whole bone marrow biopsies also include plasma cells (PC) we selected probe sets that are unique to the non-PC bone marrow ME. 783 probe sets were selected for having a log2 transformed mean expression > 8 in RNBX (in any of the 7 molecular subgroups CD1, CD2, MF, MS, HY, PR and LB) and < 8 in RNAS (in all molecular subgroups). The training set comprised 242 MM and 40 NL and the test set 136 MM and 8 NL individuals. Approximately 80% of 783 probe sets were differentially expressed between MM and NL samples. We then identified 24 differentially expressed genes to create a gene score, which differentiates between NL and MM samples. ROC plots for the training and test set are depicted in Figure 1a and 1b respectively. Boxplots of 24-gene scores showed minimal overlap between MM and NL in training and test sets (Figure 1c and 1d). 98% of patients were correctly classified as MM or NL by the 24-gene score in the test set (Table 1).Table 1True and predicted Normal and MM samples by 24-probes score in the test set. 133/136 (98%) of MM patients and 8/8 (100%) of Normal patients were classified correctly.Predicted NormalPredicted MMTrue Normal80True MM3133 We hypothesized that, upon achieving CR, the ME signature normalizes gradually reflecting the diminishing submicroscopic tumor burden and MM-inflicted ME alteration. Therefore, we applied the GEP24 model to 428 CR samples treated with Total Therapy 2 and 3 (TT2, TT3). The time course of sampling from onset of CR with annotations of normalized CR (NL-CR) and non-normalized CR (non-NL-CR) is depicted in Figure 4. Within the 1st year of CR, 14% of patients qualified for NL-CR; the corresponding values for years 2, 3 and 4 were 18%, 19%, and 20%, respectively. Normalization of the bone marrow ME was independent of GEP70 defined risk. Investigation of random biopsies from patients with asymptomatic MM (AMM) and monoclonal gammopathy of undetermined significance (MGUS) revealed a distinct stepwise shift of 24-gene score distributions with the transition from NL to MGUS to AMM and ultimately MM (Figure 5). Patients in CR had similar distributions of the 24-gene score as patients with AMM. We conclude that ME GEP provides important clues to MM biology and therapeutic response that has now been quantitated for the first time. Normalization of the bone marrow ME could predict for recovery of normal hematopoiesis. Results will be presented as to whether NL-CR status can serve as a surrogate marker for long-term disease control and cure that can aid in guiding the length of post-CR maintenance therapy. Investigations are also in progress to determine whether ME GEP can capture MDS-associated alterations and thus help in quantitating the risk of such treatment sequelae. Disclosures: No relevant conflicts of interest to declare.

Background Pom is an IMiD® immunomodulatory agent now FDA approved for treatment of patients who have received > 2 prior therapies, including lenalidomide (Len) and bortezomib (Bor), and have demonstrated disease progression on or within 60 days of completion of the last line of therapy. There is limited data evaluating efficacy of Pom in high risk RRMM. Herein, we are reporting the final report on a phase II clinical trial employing Pom in high risk RRMM with prior exposure and/or refractoriness to Len. Methods High risk RRMM was defined by having high risk on gene expression profiling (GEP70 or GEP80 signatures), elevated LDH, or having abnormal metaphase cytogenetics. Cycle #1 Pom was given at 4mg orally Days 1-21 q 4 weeks; in the absence of > PR by IMWG criteria after 2 cycles, dexamethasone (Dex, 4-20 mg orally q week) and/or Bor (1.3 mg/m2 IV days 1,4,8,11) and/or Vorinostat (Vor, 100-200 mg po days 1-21 q 4 weeks) could be added; in the absence of > PR by IMWG criteria after 4 cycles, cyclophosphamide (Cy, 300 mg/m2 q week) could be added. Primary endpoint was progression free survival (PFS) at 1 year, secondary endpoints included overall survival (OS), response rates and duration of response (DoR). Cox regression modeling was employed for univariate and multivariate analyses, Kaplan-Meier curves were used for OS and PFS. Best response was defined as the best response achieved while enrolled (regardless of prior progression, or relapse). Pharmacogenomic analyses using GEP were performed on 18 patients with paired baseline and 48hr post-Pom, using CD138-purified bone marrow plasma cells. Results 71 patients with HRMM were enrolled between May 2010 and August 2012. Baseline patient characteristics included age > 65 years in 45%, cytogenetic abnormalities (CA) in 86%, GEP70 high risk in 14/34 (41%), GEP80 high risk in 28/34 (82%), extramedullary disease in 3/71 (4%) and secondary plasma cell leukemia in 2/71 (3%). 68/71 patients (96%) had a prior autologous stem cell transplant (ASCT), 30/71 (42%) had > 2 ASCT. Patients had received a median of 5 prior lines of therapy (range 1-10). There were 58 (82%) patients with Len-refractory (Len-R) MM, 64 (90%) with Bor-refractory (Bor-R) MM and 53 (75%) with dual-refractory (dual-R) MM prior to enrollment. 34 (48%) patients received > 6 cycles of treatment, 9(13%) received > 12 cycles. Patients who received > 6 cycles, had addition of Dex(67%), Bor+Dex(18%), Bor+Dex+Cy(12%), Bor+Dex+Cy+Vor(3%). As of July 2013, 45 patients (63%) discontinued therapy primarily due to progression or death. 20 (28%) patients achieved > PR as best response (1 Len-R, 2 Bor-R, 6 in dual-R), with median DoR for patients > PR of 1 month (range 0.5-18 months). 58 patients (5 Len-R, 8 Bor-R, 43 dual-R) had > stable disease, giving an overall disease control rate of 82%. Slight PFS benefit was observed in younger patients (HR=0.64, 95% CI: (0.39, 1.06), p=0.098). An increased risk for OS was observed among patients with LDH >= 190 U/L (HR=4.62, 95% CI: (2.28, 9.38), p= 8 mg/L (HR=2.13, 95% CI: (1.03, 4.40), p= 0.041), hemogloblin < 10 g/dL (HR=3.47, 95% CI: (1.66, 7.27), p grade 3 were leukopenia (75%), thrombocytopenia (60%), anemia (44%), infections (26%), dyspnea (19%), hypophosphatemia (20%) and hypocalcemia (19%). OS and PFS at 12 months were 63% and 13%, respectively. Pre/48hr-post POM GEP analyses showed that expression levels of 55 probe-sets (48 genes) were significantly changed in response to POM treatment (false discovery rate 0.01). These genes were related to cell adhesion, inflammatory and hypersensitivity response, such as GAS6, ITGB1, ITGB7, LYN, RAC1, PYCARD, CORO1B, F11R, and DKK1, all with higher expression values observed post POM. IRF4, one of the targets of cereblon (CRBN) previously reported to be critical for myeloma cell survival, was down-regulated post POM treatment (p=0.001,FDR=0.09), suggesting a unique CRBN-dependent anti-myeloma activity for POM Conclusion Pom demonstrates good anti-myeloma activity in a heavily pretreated, GEP-defined high risk RRMM in combination with other anti-myeloma drugs. Given the efficacy in patients with poor prognostic features, there is precedence to evaluate Pom as an IMiD of choice in combination with other novel agents in front line setting for GEP-defined high risk MM. Disclosures: Usmani: Celgene: Consultancy, Research Funding, Speakers Bureau; Onyx: Research Funding, Speakers Bureau. van Rhee:Janssen Research & Development: Research Funding. Barlogie:Millennium: Consultancy, Research Funding; Celgene: Consultancy, Research Funding; MyelomaHealth: Patents & Royalties.

Abstract 4083 Background: Pom is a third generation immunomodulatory drug (IMiD) which has demonstrated safety and efficacy in RRMM with prior exposure/resistant to other IMiDs and bortezomib. This is the first report on a phase II clinical trial employing Pomalidomide (Pom) in genomically defined high risk RRMM. Methods: First cycle Pom was given at 4mg orally Days 1–21 every 28 days; dexamethasone (DEX) or bortezomib (BOZ) could be given in absence of PR or better from Cycle #3. In the absence of at least PR, Pom dose was escalated to 5mg. Cox regression modeling was employed for univariate and multivariate analyses, whereas Kaplan-Meier curves were used for overall survival (OS) and progression free survival (PFS). Results: 30 patients with RRMM were enrolled. Baseline characteristics included age >=65yr in 47%, ISS stage >=II was seen in 74% of patients, cytogenetic abnormalities (CA) within 6 months in 79%, and GEP-defined high risk in 66% by GEP70-gene model, 97% by GEP80-gene model, 13% had extramedullary disease (EMD), and 7% had secondary plasma cell leukemia (SPCL). 26/30 patients (87%) had prior autologous stem cell transplant, 23/30 patients (77%) had had at least 2 transplants. 22 patients (73%) had disease progression while on lenalidomide, bortezomib or both within 60 days of enrollment. At least 2 cycle of treatment were administered to 28 (93%) patients enrolled, 20 (67%) patients received >4 cycle of treatment and 16 (53%) received > 6 cycles. 15 patients (50%) discontinued therapy primarily due to progression or death. 5 (17%) patients achieved PR or better as best response. PFS benefit was observed in older patients (HR=0.29, p=0.008), with high LDH presenting an increased risk for OS (HR=14.64, p=0.013.) Most common toxicities, counting all toxicities (>=grade 3) were: thrombocytopenia (63%), leukopenia (63%), anemia (40%), hypophosphatemia (20%) and hypocalcemia (23%). Overall and progression- free survival at 12 months were 64% and 20%, respectively. Conclusions: The present trial is the first investigation evaluating Pom's clinical activity in high risk RRMM and demonstrates good anti-myeloma activity in this heavily pre-treated patient population. Given the activity in poor prognostic clinical features such as EMD and SPCL, there is precedence to evaluate Pom as an IMiD of choice in combination with other novel agents for this subset of RRMM. Download : Download high-res image (30KB) Download : Download full-size image Figure 1 . Kaplan-Meier Estimates of OS and PFS from Cycle 1. Table 1 . Drugs Administered by Cycle. Number of patients receiving given drug combinations in given cycle. (Note: the denominator used for calculating percentages is number of patients who started the cycle. In some columns, percentages do not add up to 100% because data was missing for some patients.) Cycle 1 (n=30) Cycle 2 (n=28) Cycle 3 (n=23) Cycle 4 (n=20) Cycle 5 (n=17) Cycle 6 (n=16) Pom alone 29 (100%) 28 (100%) 12 (52%) 7 (35%) 5 (29%) 4 (25%) Pom + Dex 0 (0%) 0 (0%) 9 (39%) 5 (25%) 5 (29%) 4 (25%) Pom + Vel 0 (0%) 0 (0%) 0 (0%) 1 (5%) 2 (12%) 2 (13%) Pom + Dex + Vel 0 (0%) 0 (0%) 1 (4%) 6 (30%) 4 (24%) 3 (19%) Disclosures: No relevant conflicts of interest to declare.

Abstract 2896 Background: Focal lesions (FL) are a well-recognized consequence of active multiple myeloma (MM), and distinguish it from its antecedent monoclonal gammopathy of undetermined significance (MGUS). We have recently reported on the superior performance of gene expression profiling (GEP) based on random trephine bone marrow aspirate sampling (RS) in distinguishing between 85% of patients with low-risk (LO) MM and 15% with high-risk (HI) MM compared to conventional prognostic variables. MM occasionally presents as macro-focal disease, in which cases RS may be inconclusive because of paucity of malignant cells in the sample. Here we report the comparison of GEP data from paired FL and RS samples from 106 untreated patients. Methods: We identified 106 newly diagnosed patients with paired samples, who were treated on Total Therapy (TT) protocols (3 in TT2, 19 in TT3, 75 in TT4, and 9 in TT5) in our multiple myeloma database. GEP risk scores, molecular subgroup classifications, overall survival (OS), and event-free survival (EFS) were compared and tested with the RS-derived 70-gene risk prediction and molecular subgroup classification models. Results: GEP defined molecular subgroups were correlated in 90 of 106 patients (85%). Looking at GEP-defined risk designation, we found a high degree of correlation between RS and FL samples with 95 of 106 samples showing the same designation (90%). For the 11 patients with divergent GEP designations, 8 (73%) were located at the boundary of the RS GEP risk score cutoff of +0.66 (range +0.43 to +0.84). For these risk designation-divergent patients, FL- but not RS-defined risk determined clinical outcome. Conclusion: Both the 70-gene risk prediction and molecular subgroup classification models can be used in FL-GEP samples. But, more importantly, for patients with RS-GEP risk score close to cutoff boundary (about 14% in our current data sets), FL-GEP provides better risk stratification, suggesting that the FL signal more adequately reflects to disease biology, progression and treatment response in MM. We therefore recommend that, for patients with borderline RS-based GEP risk scores, FL-GEP be used for staging and prognosis assessment in myeloma. Studies are in progress to determine, among multiple FL samples from the same patient, the variability in risk score compared to multiple RS samples. Disclosures: Shaughnessy: Myeloma Health, Celgene, Genzyme, Novartis: Consultancy, Employment, Equity Ownership, Honoraria, Patents & Royalties. Barlogie:Celgene: Consultancy, Honoraria, Research Funding; IMF: Consultancy, Honoraria; MMRF: Consultancy; Millennium: Consultancy, Honoraria, Research Funding; Genzyme: Consultancy; Novartis: Research Funding; NCI: Research Funding; Johnson & Johnson: Research Funding; Centocor: Research Funding; Onyx: Research Funding; Icon: Research Funding.