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Abstract Background: Diffuse large B-cell lymphoma (DLBCL) is curable for the majority of patients treated with anthracycline based immunochemotherapy (IC). However, up to 40% of patients will relapse or require retreatment of DLBCL and outcomes are poor in this setting. Here we examine the incidence, treatment patterns and outcomes of relapsed DLBCL in the R-CHOP era. Methods: Patients were prospectively enrolled in the University of Iowa / Mayo Clinic SPORE Molecular Epidemiology Resource (MER) within 9 months of diagnosis and followed for relapse, retreatment, and death. Clinical management at diagnosis and subsequent therapies were per treating physician. This analysis includes patients with DLBCL or primary mediastinal B-cell lymphoma (PMBCL) who underwent front-line anthracycline based IC; patients with primary CNS lymphoma or PTLD were excluded. All relapse and re-treatments were verified by medical record review. Response to front-line therapy was retrospectively classified per 2007 Revised Response Criteria for Malignant Lymphoma from available clinical and radiology records. Unplanned consolidative radiation (RT) without biopsy proven disease after achieving PR from IC (N=21) was not classified as a relapse. Results: 1039 patients with newly diagnosed DLBCL or PMBCL and treated with IC were enrolled in the MER from 2002-2012. Median age at diagnosis was 62 years (range 18-92) and 577 patients (56%) were male. 647 patients (63%) had stage III/IV disease and IPI at diagnosis was 0-1 in 350 patients (34%), 2 in 305 patients (29%), 3 in 250 patients (24%) and 4-5 in 134 patients (13%). At a median follow-up of 59 months (range 1-148), 258 patients had relapse or retreatment of DLBCL of which 184 (71%) died. Incidence of relapse was 21.7% (95% CI: 19.3%-24.4%) at 2 years and 25.5% (95% CI: 22.9%-28.5%) at 5 years. In addition, the incidence of lymphoma related death without documented relapse or retreatment was 4.7% (95% CI: 3.6%-6.2%) at 2 years. At first relapse, 174 patients (67% of relapsed) received platinum based salvage therapy with 90 (52%) subsequently proceeding to autologous stem cell transplant (ASCT). 22 patients received CNS directed systemic therapy at relapse with 9 (41%) proceeding to transplant, and 43 received non-platinum-based salvage systemic therapy with 7 proceeding to transplant (17%), 15 patients received RT only as 2nd line therapy, and 4 were untreated. At a median follow-up of 56 months (range 6-121) post-transplant, 39 of 107 patients who underwent transplant remain in remission with a 2-year post-transplant progression-free survival of 45% (95% CI 37%-56%). Response to front-line IC was predictive of post-relapse outcome. Survival post-relapse was superior in the 162 patients with responsive disease (CR or PR) at the end of front-line IC (median OS 21.0 months) compared to the 88 patients who had stable or progressive disease (median OS 6.8 months, HR = 2.33, 95% CI: 1.73-3.14 p<0.0001). Transient response in midst of front-line IC was similar to no response. Patients achieving a CR or PR to front-line IC were more likely to proceed to ASCT at relapse (55%) compared to patients with either SD or PD at the end of front-line IC (25% and 17% respectively, p<0.0001). Other factors associated with poor survival at first relapse were relapse within 12 months of diagnosis (HR = 2.24, 95% CI: 1.57-3.18, p<0.0001), IPI at diagnosis of 3-5 (HR=1.51, 95% CI: 1.13-2.03, p=0.0058), and age > 60 (HR =1.51, 95% CI: 1.12-2.03, p=0.0064). There was no difference in survival at first relapse by cell of origin (HR = 1.13, 95% CI: 0.74-1.72, p=0.59). Conclusions: Most patients undergo therapy after relapsed/refractory DLBCL but only one-third receive ASCT. Outcomes following all treatments for relapsed/refractory DLBCL remain poor. Factors associated with adverse outcomes include refractory to front-line therapy, early relapse, baseline IPI and advanced age. These outcomes provide relevant historical control for the many novel agents being tested in this unmet need. Figure 1. Figure 1. Disclosures Farooq: Kite Pharma: Research Funding. Maurer:Kite Pharma: Research Funding. Cerhan:Kite Pharma: Research Funding. Link:Genentech: Consultancy, Research Funding; Kite Pharma: Research Funding. Thompson:Kite Pharma: Research Funding.

Abstract Abstract 2617 Introduction: ABT-348 is a potent, novel, adenosine triphospate competitive inhibitor of Aurora A, B and C kinases. ABT-348 is also a potent inhibitor of all members of the vascular endothelial growth factor (VEGF) and platelet-derived growth factor (PDGF) receptor tyrosine kinase (RTK) families. ABT-348 has demonstrated strong antitumor activity in a variety of preclinical cancer cell line models, in vitro and in vivo, including leukemias as monotherapy and in combination with the DNA methyltransferase inhibitor, azacitidine. Objectives: The primary objectives of this study are to determine the safety and pharmacokinetics (PK) of orally and IV administered ABT-348 as monotherapy or in combination with azacitidine in patients (pts) with advanced hematologic malignancies. Secondary objectives include determination of the maximum tolerated dose (MTD) and exploration of biomarkers associated with ABT-348 activity. Methods: This phase 1 dose-escalation study of ABT-348 utilizes a modified continual reassessment method in pts with advanced hematologic malignancies: acute myelogenous leukemia (AML), acute lymphoblastic leukemia, chronic myelogenous leukemia (CML), chronic lymphocytic leukemia and myelodysplasia (MDS). Adult pts with histological or cytological confirmed disease, ECOG status 0–2, adequate hematological, renal and hepatic function and without significant hypertension or proteinuria are eligible. This study has four arms consisting of ABT-348 administered on a 28-day (D) cycle. Pts receive ABT-348 monotherapy once daily (QD, Arm A) or twice daily (BID; Arm B) on Days (D) 1, 8, and 15 of a 28-day cycle under fasting conditions. In Arm C, ABT-348 is given on the same schedule as Arm A in combination with azacitidine (75 mg/m2) administered IV or SC on Days 1 – 7 of each 28-day cycle. In Arm D, pts receive ABT-348 monotherapy on the same schedule as Arm A, but via IV administration. Samples are collected for PK and biomarker analyses. Pts are treated until progressive disease (PD) or unacceptable toxicity. Adverse event (AE) severity is graded using NCI-CTCAE v4.0. Results: 39 pts (median age, 66 y [45–86]) have enrolled (Arm A, n=32; Arm B, n=4; Arm C, n=3). Of these pts, 27 had AML, 11 had MDS and 1 had CML. Pts received a median of 4 prior therapies (range, 1 – 8). Best response to last prior therapy was: complete or partial response in 3 pts, stable disease in 11 pts, PD in 24, and not determined in 1. Dose escalation is shown in the table. The first dose-limiting toxicity (DLT) of grade 3 pancreatitis was observed at 640 mg in Arm A. Due to this DLT, along with a second case of grade 3 pancreatitis, further enrollment in Arm A was held and Arms B and C were opened. A DLT of grade 4 acute kidney injury was seen at 440 mg in Arm C. ABT-348-related AEs in greater than 2 pts were proteinuria (23%), nausea (21%), diarrhea (18%), hypertension (13%), vomiting (10%) and fatigue (8%). Grade 3/4 ABT-348-related AEs were hypertension (13%), pancreatitis (5%), acute kidney injury (3%) and diarrhea (3%). One patient in Arm A achieved a CRi (640 mg). Five of 32 pts in Arm A were treated for ≥4 cycles, including 2 of 7 pts at ABT-348 doses ≥ 640 mg. Based on preliminary PK analyses, Cmax and AUC of ABT-348 were approximately dose proportional in the dose range studied (10–690 mg); co-administration of azacitidine had no apparent effect on ABT-348 PK. Evidence of dual aurora/VEGF receptor kinase inhibition has been demonstrated by induction of polyploidy and PlGF, respectively. 33 pts have discontinued and 6 remain on study. Conclusions: ABT-348 has demonstrated on-target biomarker and clinical activity in pts with advanced hematologic magnancies, and was well tolerated at doses below 640 mg in Arm A. PK appears to be dose-proportional. Dose escalation is ongoing in Arms B and C (with azacitidine); an IV formulation of ABT-348 will also be evaluated. Disclosures: Off Label Use: Clofarabine in AML. Tibes:Abbott: Research Funding. Chiu:Abbott: Employment, Owns stocks Other. Xiong:Abbott: Employment, own Abbott stock Other. Qin:Abbott: Employment. Ansell:Abbott: Employment, own Abbott stock Other. Albert:Abbott: Employment, own Abbott stock Other. Tse:Abbott: Employment, own Abbott stock Other. Oliver:Abbott: Employment, own Abbott stock Other. Sajwani:Abbott: Employment, own Abbott stocks and participated in study design, data collection, analysis, interpretation and reviewing approving study documents related to ABT-348 programs. Other. McKee:Abbott: Employment, own Abbott stocks Other. Ricker:Abbott: Employment, own Abbott stocks Other.

Abstract Introduction The Classic Myeloproliferative Neoplasms (MPNs), characterised by an over production of one or more cells of the myeloid lineage, are classified into polycythaemia vera (PV), essential thrombocythaemia (ET) and primary myelofibrosis (PMF). Despite the identification of numerous genetic mutations, a paucity of information relating to medical and lifestyle factors contributing to the aetiology of these diseases remains. Methods The MOSAICC Study was an exploratory case-control study of MPNs. MPN patients were recruited between two sites, Belfast and Southampton, in preparation for a planned UK-wide investigation. Population controls (identified by General Practitioners) and non-blood relative/friend controls were also recruited. Participants completed a telephone-based questionnaire seeking information on a range of medical, environmental, lifestyle and occupational risk factors. Risk factors were assessed using unconditional logistic regression with adjustment for potential confounders. Results Risk factors identified included smoking [≥25 pack years vs. never: odds ratio (OR) 3.14, 95% confidence interval (CI) 1.26-7.87], increasing childhood household density [>2 vs <1 Child(ren)/room: OR 3.29, 95% CI 1.31-8.30], history of heart disease (OR 3.31, 95% CI 1.23-8.87), CT scans (≥3 vs. none: OR 4.92, 95% CI 1.55-15.67), having an implant (OR 10.77, 95% CI 1.01-3.10), and pig ownership (OR 5.92, 95% CI 1.17-29.92). Alcohol was associated with a reduced risk of MPNs (OR 0.49, 95% CI 0.28-0.88) as was home working on car exhausts (OR 0.33, 95% CI 0.12-0.88), painting at home (OR 0.49, 95% CI 0.28-0.86) and short haul air travel (p for trend 0.012). Participants working in occupations with high exposure to environmental tobacco smoke had an excess risk of MPN (OR 2.45, 95% CI 1.12-5.37). Work-based radiation and solvent exposure also appeared to increase risk of MPNs (p<0.05). Conclusions This exploratory study has confirmed a reported association between cigarette smoking and MPNs. It has identified some potential novel risk factors including work-based radiation and solvent exposure. The findings of this study need to be replicated in a larger, adequately powered, study in order to identify important risk factors for the classic MPNs. Conflict of Interest The authors declare no conflict of interest. Acknowledgments: The MOSAICC Study team acknowledges the support of the National Institute for Health Research, through the Northern Ireland Cancer Research Network (NICRN) and for Southampton the Central South Coast Cancer Network (CSCCN). The team thank those who have participated in the MOSAICC study and the personnel who assisted in the recruitment of patients. Disclosures Mesa: CTI Biopharma: Research Funding; Promedior: Research Funding; Novartis Pharmaceuticals Corporation: Consultancy; Incyte Corporation: Research Funding; Pfizer: Research Funding; NS Pharma: Research Funding; Genentech: Research Funding; Gilead: Research Funding.

Abstract Background: Ixazomib is an experimental, orally bioavailable, proteasome inhibitor that has demonstrated anti-tumor activity in relapsed multiple myeloma (MM). In the dose escalation studies, ixazomib was tolerated up to a dose of 5.5 mg given every week as a single agent, while a dose of 4 mg was utilized in the combination studies with lenalidomide. We undertook this study to examine the efficacy and tolerability of the two doses of ixazomib in combination with dexamethasone in patients with relapsed MM. Patients and methods: This was a randomized phase 2 study of two doses of ixazomib (4mg; Arm A or 5.5 mg; Arm B) given weekly for three weeks with a week off along with weekly dexamethasone (40 mg) in patients with relapsed MM, who are proteasome inhibitor na•ve (including bortezomib) or have received less than 6 cycles of therapy with bortezomib and had a PR or better with no progression at the time of discontinuation. The primary objective was to determine the confirmed overall response rate (>=PR); secondary objectives included progression free and overall survival. A total of 71 patients were accrued from February 2013 to April 2015; one patient was ineligible. Results: Baseline characteristics were similar in the two arms; median age across the study was 70 years (46-84); 53% were male. Median number of prior therapies was 4 (range 2-6); 90% of the patients had prior IMiDs, 70% had prior transplant and 29% had prior bortezomib. At a median follow up of 10 months, 17 (49%) and 19 (54%) of patients had disease progression in arms A and B respectively with 12 (34%) patients in each arm still continuing on treatment. All patients in each arm were evaluable for response; the overall response rates were 31% in arm A (95%CI: 17-49) and 51% (95%CI: 34-69) in Arm B. The depth of response, event free survival and overall survival are outlined in Table 1. Among the patients with no prior bortezomib exposure the response rates were 38% for Arm A and 52% for Arm B. The treatment was well tolerated with 2 patients in each arm discontinuing treatment for adverse events; there were no on study deaths. A grade 3 or higher AE that was at least possibly related to treatment was seen in 21% and 54% in Arms A and B respectively; with 15% and 37% hematologic and 6% and 29% non-hematologic AEs. The most common attributable toxicities encountered included fatigue, thrombocytopenia, diarrhea and nausea with more grade 3 toxicities among Arm B. Peripheral neuropathy, possibly related to ixazomib, was seen in 55% (only grade 1 or 2) in arm A and 43% (2 patients with grade 3) in Arm B. Toxicities led to dose reduction of ixazomib in 17% and 43% of patients in Arm A and B respectively; the median number of cycles administered were 5 (1-24) and 5 (1-22) respectively. Conclusions: Ixazomib in combination with dexamethasone was well tolerated with significant anti-myeloma activity in this group of patients with relapsed MM. Deep responses including stringent CR were observed. The higher dose of ixazomib appears to be associated with a higher response rate but with higher rate of adverse events requiring dose reductions. Table 1. Treatment outcome in all patients Arm B (4 mg) (N=35) Arm C (5.5 mg) (N=35) Response Rate 31% (95%CI: 17-49) 51% (95%CI: 34-69) No. of Responders 11 18 sCR 0 1 CR 1 0 VGPR 7 8 PR 3 9 MR 5 1 Median Overall Survival1 NA NA 6 Months 100% 100% Median Event Free Survival1,2 8.4 mos (95%CI: 4.3-13.2) 8.2 mos (95%CI: 3.8-16.3) %Event Free at 6 Months 60% (95%CI: 45-81) 60% (95%CI: 45-81) Median Duration of Response1 16.7 mos (95%CI: 9.3-22.0) 16.3 mos (95%CI: 7.0-20.1) Median Time to Response 1.1 mos (range: 0.8-3.6) 1.0 mos (range: 0.8-7.5) CI: confidence interval; mo: month; NA: not attained 1Kaplan Meier 2Event-free survival time is defined as the time from registration to the first of disease progression, death due to any cause, or subsequent treatment for multiple myeloma. Disclosures Kumar: Celgene: Consultancy, Research Funding; Sanofi: Consultancy, Research Funding; Skyline: Consultancy, Honoraria; Onyx: Consultancy, Research Funding; Novartis: Research Funding; Janssen: Consultancy, Research Funding; Takeda: Consultancy, Research Funding; BMS: Consultancy.

Abstract Abstract 468 The requirement for BAFF and BAFF-R in normal human and murine B cells is well studied, but there is also significant evidence to suggest that BAFF plays an important role in malignant B cell proliferation and survival. Serum BAFF levels are elevated in patients with non-Hodgkin lymphoma (NHL) and high BAFF levels correlate with aggressive disease and a poor response to therapy. There is also increasing genetic evidence suggesting an association between the development of human disease and genetic variation in genes encoding BAFF and its receptors. Mutations in TNFRSF13B (TACI) were identified in patients with familial common variable immunodeficiency (CVID) and IgA deficiency and we have found that single nucleotide polymorphisms (SNP) in TNFSF13B (BAFF) are associated with elevated BAFF levels and risk for developing NHL. To build upon these findings we sequenced BAFF and its receptors; TNFSF13B, TNFRSF13B, TNFRSF17(BCMA), and TNFRSF13C (BAFF-R) in NHL patients to identify novel genetic variants that may be associated with NHL risk. Among 40 individual samples (20 controls and 20 follicular lymphoma (FL) cases) that were bi-directionally sequenced we identified a heterozygous cytosine to thymidine transition in 1 patient specimen at position 475 (C475T) of TNFRSF13C. The C475T transition encodes a missense substitution of tyrosine for histidine in codon 159 (H159Y) in the highly conserved cytoplasmic tail of BAFF-R, adjacent to the TRAF3 binding motif PVPAT. We next expanded our analysis of BAFF-R H159Y and analyzed NHL tumor biopsies for the presence of the mutation. 4/41 (10%) follicular lymphomas (FL), 2/42 (5%) diffuse large B cell lymphomas, 1/22 (5%) lymphoplasmacytic lymphomas (LPL), and 1/24 (4%) mucosal associate lymphoid tissue lymphomas carried the heterozygous mutation. The BAFF-R H159Y mutation was not detected in any of the normal control DNA from healthy donors (n=100). Given its close proximity to the TRAF3 binding site in the cytoplasmic domain of BAFF-R we first wanted to determine if the H159Y mutation altered BAFF induced signaling. We generated cell lines that express HA-tagged wildtype BAFF-R, BAFF-R with the H159Y mutation, or BAFF-R with an ablated TRAF3 binding site as a negative control. Analysis of cells expressing H159Y BAFF-R demonstrates that this mutation results in increased BAFF-R-mediated NFκB1 and NF-κB2 activation. The enhanced signal activated by BAFF-R H159Y is coupled with a several fold increase in TRAF3, TRAF2, and TRAF6 recruitment to BAFF-R and increased IgM production. We further demonstrate that recruitment of TRAF6 to BAFF-R is not unique to the mutant H159Y BAFF-R, but is also an important and necessary feature of BAFF-R signaling in normal B cells. Collectively, our data identify a novel lymphoma-associated mutation in BAFF-R and describe exciting new aspects of BAFF-R signaling that are important for understanding normal B cell homeostasis and function, as well as pathogenic BAFF-R contributions to human disease. Disclosures: No relevant conflicts of interest to declare.

Abstract Abstract 1958 Vaccines may offer additional benefit as consolidation therapy after plateau phase or autologous stem cell transplant (ASCT) for multiple myeloma (MM). We have reported previously the results of another phase II trial showing that using APC8020 (Mylovenge™) after ASCT improved the overall survival (OS 5.3 yrs, 95% CI 4.0 yrs – NA) compared to ASCT alone (3.4 yrs, 95% CI 2.7 – 4.6 yrs; p = 0.02; Lacy, AJH (84): 799). We now report the results from a randomized, phase II trial using the same vaccine plus adjuvant cytokines in MM patients in plateau phase after either chemotherapy or ASCT. Twenty patients were enrolled between 2001 and 2003 and were randomized to receive APC8020 and adjuvant cytokine of either interferon-g (IFNg, arm A, n = 10) or interleukin-2 (IL2, arm B, n = 10). Each cycle of treatment included five days of daily subcutaneous injections of either IFNg (106 IU, arm A) or IL2 (200 mg, arm B) followed by APC8020 injection. Each patient received a cycle of treatment every 2 weeks for 4 cycles. One patient in each arm was in plateau phase post-chemotherapy. Time from diagnosis to treatment was 11.9 mos for the patient in arm A and 16.2 mos for arm B. Time to progression (TTP) was 3.7 and 68 months respectively the patient in arm A and B. Both patients were alive at five years. For the 9 post-ASCT patients in each arm, no statistically significant differences were seen in the baseline characteristics between the 2 arms. The median time from diagnosis to treatment was 15.4 months. No grade 4 or 5 adverse events (AEs) were reported. Two patients in each arm had grade 3 AE, including lymphopenia, thrombocytopenia, hemorrhage, infection, and fatigue. One patient in arm B had grade 3 autoimmune disorder that was deemed possibly related to study treatment. The most common AEs were grade 1 fatigue (n = 7) and anemia (n = 5) in arm A and grade 1 anemia (n = 7) and injection site reaction (n = 5) in arm B. The median TTP was 9.3 months (95% CI: 3.9 – 19.3 months) for arm A and 6.6 months for arm B (95% CI: 6.3 – 29.6 months) with no statistically significant difference between the two arms (p = 0.89). The median OS had not been reached for either arm; the 5-year OS rate was 67% and 56% for arms A and B respectively (p = 1.0). Interestingly, similar to our previous study where TTP was not different while OS was improved with vaccine, when we compared the clinical outcome for all patients in this vaccine trial to that of 78 matched control patients who only received ASCT during the same time frame, we did not see significant improvement in TTP (Figure 1). However, the 5-year overall survival for all patients in this trial is significantly improved at 71% (95%CI: 51–96%) compared to ASCT control patients (41%, 95% CI: 31 – 54%; p = 0.03; Figure 1). This trial suggests improved OS with vaccine plus cytokine. It is possible that modulation of patients’ immunity may help them live longer with multiple myeloma. Further investigation is needed to compare the approach in this trial with dendritic cell vaccine alone to better understand optimal strategy for vaccine therapy in MM. Figure 1. Kaplan-Meier curves for time to progression and overall survival Figure 1. Kaplan-Meier curves for time to progression and overall survival Disclosures: Dispenzieri: Celgene: Honoraria, Research Funding; Binding Site: Honoraria. Kumar:Celgene: Consultancy, Research Funding; Millennium: Research Funding; Merck: Consultancy, Research Funding; Novartis: Research Funding; Genzyme: Consultancy, Research Funding; Cephalon: Research Funding. Lacy:Celgene: Research Funding.

Abstract Background: Amyloidosis is a multisystem disease with extracellular deposition of pathological insoluble beta-fibrillar proteins. Involvement of the heart is seen in more than one-half of the patients with systemic AL amyloidosis and it is the most important determinant of clinical outcome. Cardiac amyloidosis is a restrictive infiltrative cardiomyopathy in which, despite declines in stroke volume that accompany disease progression, the ejection fraction (EF) often remains preserved even in advanced stages of the disease. King et al. proposed a novel index of myocardial function, the myocardial contraction fraction (MCF), defined as the ratio of stroke volume (SV) to myocardial volume (MV). MCF is a measure of myocardial shortening, which differentiated myocardial performance in patients with similar degrees of hypertrophy and in a recent small cohort of AL amyloidosis patients appeared superior to left ventricular ejection fraction (EF) in predicting overall survival (OS). It was our goal to assess the prognostic role of MCF in a large cohort of patients with AL amyloidosis in the context of other prognostic variables. Methods: Patients seen between 4/1/1999 and 2/1/2015 were eligible for this retrospective study if they had an ECHO at the Mayo Clinic, Rochester, MN within 30 days of their AL amyloidosis diagnosis with measurements of left ventricular chamber size and wall thickness needed to calculate MCF, EF, and the presence or absence of pericardial effusion. To capture the full cohort, modeling was done first excluding Mayo (2012) staging and global averaged left ventricular longitudinal peak systolic strain (LV strain) since limited numbers of patients had these studies, 342 and 294, respectively. Thresholds of continuous variables were chosen based on receiver operator curves targeting death at 1-year. Cox proportional hazards analysis was used to identify factors that were prognostic for OS. Statistical analyses were done using JMP 9.0 (SAS, Cary, NC). Results: Among the 722 patients satisfying entry criteria,median age was 64 years (range 32-94) and 66% were male. The best cutoff for MCF was 21% (sensitivity: 74%, specificity: 60%; AUC=0.699) and distinguished two groups with different OS (median 53 vs. 9 months, P<0.0001; Figure). On univariate analysis the baseline ECHO variables predicting OS were interventricular septum thickness (IVS) >12 mm (RR 1.8, P=0.0002), EF <60% (RR 1.7), MCF ≤21% (RR 2.1), and presence of pericardial effusion (RR 2.0), all with P<0.0001. On multivariate MCF ≤21% (RR 1.6, P <0.0001), EF <60% (RR 1.4, P=0.0007) and the presence of pericardial effusion (RR 1.3, P=0.002) were independent predictors of OS. Additional modeling was done with the subset of 342 patients who were assessable for Mayo (2012) staging, (i.e. measurements of immunoglobulin free light chain, NT-proBNP, and troponin T). On univariate analysis, patients with a Mayo (2012) stage ≥ 3 had a RR 2.1, p<0.0001. On multivariate, only MCF ≤21% (RR 1.5, P =0.01), Mayo (2012) stage ≥ 3 (RR 1.5, P=0.01) and EF<60% (RR 1.7, P=0.0006) were independent prognostic determinants. Finally, we addressed LV-strain among the 294 patients in whom the study was performed. There was a significant correlation between MCF and LV strain (rho =-0.86, P<0.0001). On univariate, LV-strain less negative than -13 generated a RR of 2.3, p<0.0001. In contrast to the model containing MCF, on LV-strain multivariate, EF was no longer significant, but LV-strain less negative than -13 (RR 2.0, P=0.008) and Mayo (2012) stage ≥ 3 (RR 2.0, P=0.008) predicted independently OS. Conclusions: MCF ≤21% identified a subgroup of patients with a high mortality risk, and it was independent of the Mayo (2012) staging but highly correlated with LV strain. An advantage of MCF, which is a novel volumetric measurement of the left ventricular chamber, is that, unlike LV-strain, MCF is simple to calculate from routine ECHO measures. Figure 1. Overall survival of 722 patients according to MCF<21%. Figure 1. Overall survival of 722 patients according to MCF<21%. Disclosures Kumar: AbbVie: Research Funding; Celgene: Research Funding; Janssen: Research Funding; Skyline, Noxxon: Honoraria; Celgene, Millenium, Sanofi, Skyline, BMS, Onyx, Noxxon,: Other: Consultant, no compensation,; Sanofi: Research Funding; Millenium/Takeda: Research Funding; Onyx: Research Funding.

Abstract Dexamethasone is a powerful anti-inflammatory, immunosuppressive agent widely used in the treatment of MM with pleiotropic effects on both the tumor, and host immune cells. We report on a completely novel approach to immune modulation using an agent with almost directly opposite effects to glucocorticoids on innate immune cells. LCL161 is an IAP antagonist targeting the cellular inhibitor of apoptosis proteins cIAP1 and -2 (cIAP1/2) that in a phase I study in solid tumors was well tolerated with a cytokine release syndrome as the dose limiting toxicity. We previously reported that loss of cIAP1/2 in MM cells results in the stabilization of NIK and activation of the non-canonical NFkB pathway, a pathway we found frequently activated by a promiscuous array of mutations in multiple myeloma (MM). As expected, we found that LCL161 has no direct anti-tumor activity against MM cells in vitro and ex vivo. However, the non-canonical NFkB pathway is also a key activator of the innate immune response. Remarkably, we found that in vivo LCL161 has dramatic, apoptosis-independent activity associated with marked phagocytosisagainst MM that develops spontaneously in an immunocompetent genetically engineered mouse model of MM (Vk*MYC). Cyclophosphamide (Cy), which has been shown to induce an acute secretory activating phenotype in tumor-associated macrophages, markedly potentiated the anti-tumor effects of LCL161. We show that phagocytes (depleted by liposomal clodronate), but not adaptive immune cells, are required for the anti-tumor effect. Consistently we show that LCL161 activates dendritic cells and macrophages in vitro, and in vivo, and upregulates production of inflammatory cytokines. A phase 2 clinical trial of LCL161 was conducted in 24 patients with relapsed MM previously exposed to both IMiDs and PIs, but less than 5 prior lines of therapy. Patients received LCL161 1200mg po weekly, with Cy 500mg po weekly added for progressive disease or lack of response. Single agent LCL161 was well-tolerated, with grade 3 or 4 non-hematologic toxicity in four patients, and following the addition of cyclophosphamide in 9 patients. No patients responded to single agent LCL161, and the best response was stable disease in 6/24. In 21 patients, Cy was added after a median of 2 cycles, in whom the best response was stable disease or better in 18/21 (p<0.001 compared to LCL161 alone), and a PR or better (including 1 VGPR and 1 CR) in 5/21 (p<0.001 compared to LCL161 alone). Six months following the initiation of Cy, 35% of patients remain event-free. Two patients had stable disease for more than nine months after stopping treatment. One, relapsing after VDT-PACE, HDM200, RVd x 3 years with t(11;14) and del17p, received only three months of LCL161, the last month in combination with Cy. He then achieved a PR, reconstitution of his uninvolved IgG to normal levels for the first time in more than 3 years and still has not progressed one year after stopping therapy. Similar changes in serum and bone marrow inflammatory cytokines and gene expression were observed in patients following treatment with LCL161 to those observed in the mice. We conclude that LCL161 is able to modulate the tumor microenvironment to exert long-term disease control in combination with Cy, and deserves further study in combination with agents that more directly depend on phagocytic cell activity (e.g., monoclonal antibodies, inhibitors of "Don't eat me" signals). Disclosures Bergsagel: Novartis: Research Funding; Constellation Pharmaceuticals: Research Funding; Incyte: Consultancy; Jannsen: Consultancy; Mundipharma: Consultancy. Off Label Use: Use of LCL161 to treat multiple myeloma. Kumar:Celgene: Research Funding; Millenium/Takeda: Research Funding; Onyx: Research Funding; AbbVie: Research Funding; Janssen: Research Funding; Sanofi: Research Funding; Celgene, Millenium, Sanofi, Skyline, BMS, Onyx, Noxxon,: Other: Consultant, no compensation,; Skyline, Noxxon: Honoraria. Stewart:Oncospire Genomics: Research Funding.

Abstract Background Immune editing is a major mechanism used by tumors to promote their survival. We have previously reported the presence of immunosuppressive monocytes (CD14+HLA-DR low/neg) in a number of cancers. Increased presence of these cells was associated with decreased treatment response and OS. Here we report an in vitro model to examine tumor monocyte cross talk and demonstrate that these monocytes may directly promote tumor cells’ resistance to chemotherapy. Method Monocytes from healthy donors were co-cultured with lymphoma cell lines (OCI-Ly1, OCI-Ly3, OCI-Ly7, OCI-Ly10, Su-DHL2, Su-DHL6, Jeko-1, Granta-519) with or without doxorubicin (DOX). Cultured cells were assessed for phenotype, viability, proliferation, and induced protein expression. Changes in vitro were confirmed in primary tissue by gene expression profile from 48 primary diffuse large B cell (DLBCL) lymphoma tumors. Results Monocytes converted CD14+HLA-DR+ to the CD14+HLA-DRlow/neg phenotype by co-culture with 5 of the 8 B cell lymphoma cell lines. The HLA-DR suppression was not due to the known regulatory effects of IL-10 nor was the effect seen in co-culture using B cells from healthy donors. Thus, the magnitude of DR loss is mediated by a yet undetermined mechanism. DOX incubation induced apoptosis in all of the cell lines. Co-culture with monocytes improved lymphoma cell survival in 3 of the 4 lymphoma cell lines. For example, untreated OCI-Ly3 had a 1.3±0.2 fold expansion that was reduced to 0.6±0.1 when treated with DOX (p<0.0001, n=13). However, when the cells were treated with DOX and co-cultured with monocytes the survival improved to 0.8±0.2 (p<0.0001, n=13). Having previously shown that CD14+HLA-DRlow/neg were capable of suppressing patient immunity, partially through arginase I, we determined if co-culture of monocytes with tumor cells increased arginase I expression in either monocytes or tumor cells. Not only did we see arginase I expression increases during co-culture(n=10, p<0.01), but surprisingly, the greatest increases were seen during co-culture and DOX treatment (n=10, p=0.01). To determine if our in vitro observations reflect human tumors, we used gene expression data obtained from 48 DLBCL tumors and found that increased CD14 gene expression was positively correlated with increased arginase I expression (n=48, p=0.02). Conclusions We have demonstrated that certain tumor cells induced phenotype changes in monocytes in an IL-10 independent and a tumor specific way. In those cells where tumors factors mediate monocyte phenotype, the monocytes can promote tumor cell resistance to cytotoxic killing by DOX, thus demonstrating a cross-talk between monocyte and tumor function. We found that in an environment of monocyte/tumor cross talk, arginase I expression is further increased in a cytotoxic environment. Together, this data demonstrates an active cross talk between monocytes and tumors resulting in multiple mechanisms of tumor resistance to chemotherapy. Disclosures: No relevant conflicts of interest to declare.

Abstract Chronic Lymphocytic Leukemia (CLL) is primarily characterized by the presence of leukemic B lymphocytes resistant to the process of apoptosis. Causes for this resistance include aberrant expression of multiple anti-apoptotic proteins, perhaps including Tcl-1 (1). Tcl-1 is expressed during normal development of both B and T cells and activates Akt to provide a survival signal through phosphorylation and inactivation of apoptotic pathway components. Overexpression of Tcl-1 in the B cells of transgenic mice results in a B-cell leukemia phenotype typical of human CLL, suggesting a primary role for Tcl-1 in CLL tumorigenesis. A recent report showed that Tcl-1 protein expression in CLL cells correlated with other biological parameters, but no data were available as to its clinical relevance (2). We therefore examined Tcl-1 expression in relation to clinical outcome using 51 peripheral blood mononuclear cell samples from a Phase II clinical trial testing the combination of pentostatin, cyclophosphamide, and rituximab in previously untreated CLL patients (Kay et al., ASH 2006). Tcl-1 protein expression was measured by immunoblot using GAPDH as a normalization control across lanes and lysate from a single Tcl-1 transgenic mouse spleen as a normalization control across immunoblots. All samples were run at least in duplicate and digital quantitation was performed using a ChemiDoc instrument (BioRad). Tcl-1 expression in patient cells was calculated in comparison to Tcl-1 expression in the mouse lysate, arbitrarily set to 1.0. Data were analyzed as a continuous measure as well as by specific cutoffs. Higher Tcl-1 expression was associated with failure to achieve a minimal residual disease-negative state after treatment. Specifically, Tcl-1 expression (measured as a continuous variable) was associated with residual disease measured by post-treatment CD5+/CD19+ cell percentages (continuous variable as well as dichotomized by cutpoint of 1.0% for CD5+/CD19+; p=0.03 for both comparisons). For the dichotomized Tcl-1 expression with the cutpoint of 0.275 (second tertile), this variable was marginally significantly associated with whether or not post-treatment CD5+/CD19+ was less than 1.0%. Using this same cutoff, there was also a suggestion that patients with reduced Tcl-1 were more likely to achieve a complete response. Finally, progression-free survival was shorter in patients with increased Tcl-1 expression, although these data did not reach statistical significance in this sample set. Tcl-1 < 0.275 Tcl-1≥ 0.275 p value CD5/CD19≥ 1% 15 10 0.046 CD5/CD19 < 1% 16 2 CR 17 3 0.064 No CR 18 13 Median PFS (mos.) 36.5 17.1 0.137 Statistically significant associations with other parameters including Rai stage, IgVH mutation status, ZAP-70 expression, CD38 expression, and interphase cytogenetics categories were not detected in this sample set. These data further support the clinical relevance of the Tcl-1 mouse model to human CLL, and provide preliminary evidence that Tcl-1 protein expression correlates with clinical outcome of CLL patients treated with chemoimmunotherapy. If validated in larger studies, Tcl-1 expression may serve as a novel prognostic factor.