Citations

Abstract Background Ixazomib, the first oral proteasome inhibitor, is approved by the US FDA, in combination with Rd, for the treatment of MM patients (pts) who have received at least 1 prior therapy. Approval was based on the double-blind, placebo-controlled phase 3 TOURMALINE-MM1 study (NCT01564537) in 722 pts with RRMM (Moreau et al, N Engl J Med 2016), in which IRd showed superior PFS versus placebo-Rd (HR 0.74) at the final prespecified analysis, with limited additional toxicity. Prespecified subgroup analyses showed a consistent PFS benefit with IRd, but with a differential treatment effect according to prior therapy exposure. An exploratory study objective was to evaluate potential relationships between treatment outcomes and tumor gene expression patterns. c-MYC is a proto-oncogene that encodes a transcription factor regulating cell proliferation, growth, protein translation, metabolism, and apoptosis, and increased c-MYC expression is involved in MM pathogenesis/progression. We analyzed the impact of c-MYC expression on PFS in RRMM pts treated with IRd or placebo-Rd. Methods Pts with RRMM after 1-3 prior lines of therapy were randomized 1:1 to receive oral ixazomib or placebo, plus lenalidomide and dexamethasone, until disease progression or unacceptable toxicity. Randomization was stratified by number of prior therapies (1 vs 2-3), proteasome inhibitor exposure, and ISS disease stage. The primary endpoint was PFS by independent review committee assessment. Data reported here are from the final prespecified statistical analysis of PFS (median follow-up ~15 months). Bone marrow aspirate samples were collected at screening for tumor gene expression analysis. Whole transcriptome sequencing (RNAseq) of bone marrow-sorted CD138+ cells was performed using the Illumina Truseq protocol on the Illumina HiSeq platform; this generated a median of 50 million paired-end reads (100 bp length) per sample. c-MYC expression was evaluated by treatment arm and according to number of prior therapies (1 vs 2-3). PFS was analyzed in subgroups dichotomized according to median c-MYC expression (c-MYC-high/c-MYC-low). Results RNAseq data were available for 59% (427/722) of enrolled pts; 213 (50%) had high and 219 (50%) had low c-MYC expression (dichotomized according to the median). Impact of c-MYC expression (high vs low) on PFS, irrespective of treatment arm, was not significant (p=0.98). However, a significant treatment effect of IRd vs placebo-Rd was only seen in pts with high c-MYC expression (interaction p=0.024); in these pts (IRd: n=109; placebo-Rd: n=104) a significant PFS benefit was seen with IRd (HR 0.41; 95% CI: 0.26-0.65, p=0.00011). Impact of c-MYC expression was then analyzed by number of prior therapies. In the overall TOURMALINE-MM1 population, per stratification, 212/213 pts in the IRd/placebo-Rd arms had 1 prior therapy, and 148/149 had 2-3 prior therapies. After median follow-up of ~15 months, median PFS in pts with 1 prior therapy was 20.6 vs 16.6 months with IRd vs placebo-Rd (HR 0.88; 95% CI: 0.65-1.20), and in pts with 2-3 prior therapies was not reached vs 12.9 months (HR 0.58; 95% CI: 0.40-0.84, p=0.0033). The level of c-MYC expression was shown to be significantly higher in pts with 2-3 prior therapies vs 1 prior therapy, with median expression of 6.94 (SD=1.71, n=177) vs 6.52 (SD=1.74, n=250) (log2 scale), t-test p-value 0.0153. In pts with 1 prior therapy, no differences in PFS were observed between pts with low c-MYC expression (HR 1; 95% CI: 0.59-1.8, p=0.934), while a prolonged PFS benefit was observed in pts with high c-MYC expression (HR 0.48; 95% CI: 0.26-0.88, p=0.0146) (Figure, A and B). In pts with 2-3 prior therapies, both the c-MYC-high and c-MYC-low pts showed improved PFS with IRd vs placebo-Rd; the difference in PFS was statistically significant only in c-MYC-high pts (HR 0.36; 95% CI: 0.18-0.72, p=0.00269) (Figure, C and D). Conclusions In TOURMALINE-MM1, c-MYC expression was higher in MM tumor samples from pts with 2-3 vs 1 prior therapies. The IRd regimen was active in c-MYC-high and c-MYC-low pts, but its impact on PFS vs placebo-Rd was greater in c-MYC-high pts, thus providing a potential explanation for the enhanced PFS benefit with IRd vs placebo-Rd in pts with 2-3 prior therapies. The PFS benefit with IRd in c-MYC-low pts with 2-3 prior lines suggests that, in advanced MM, further genomic alterations may also be contributing to ixazomib sensitivity. Disclosures Di Bacco: Millennium Pharmaceuticals Inc., Cambridge, MA, USA, a wholly owned subsidiary of Takeda Pharmaceutical Company Limited: Employment. Bahlis:BMS: Honoraria; Onyx: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; Celgene: Consultancy, Honoraria, Other: Travel Expenses, Research Funding, Speakers Bureau; Janssen: Consultancy, Honoraria, Other: Travel Expenses, Research Funding, Speakers Bureau. Avet-Loiseau:Takeda: Speakers Bureau; Janssen: Speakers Bureau; Celgene: Speakers Bureau; Sanofi: Speakers Bureau. Masszi:Janssen-Cilag: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees; BMS: Membership on an entity's Board of Directors or advisory committees. Ganly:Medipics: Equity Ownership; Novartis: Honoraria; Roche: Honoraria. Cavo:Bristol-Myers Squibb: Consultancy, Honoraria; Millennium: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; Janssen-Cilag: Consultancy, Honoraria; Celgene: Consultancy, Honoraria. Langer:Celgene: Consultancy; Takeda: Consultancy; Janssen: Consultancy; Amgen: Consultancy; Novartis: Consultancy. Kumar:Array BioPharma: Consultancy, Research Funding; Janssen: Consultancy, Research Funding; Sanofi: Consultancy, Research Funding; AbbVie: Research Funding; Onyx: Consultancy, Research Funding; Noxxon Pharma: Consultancy, Research Funding; Glycomimetics: Consultancy; Kesios: Consultancy; BMS: Consultancy; Millennium: Consultancy, Research Funding; Skyline: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Research Funding. Berg:Millennium Pharmaceuticals Inc., Cambridge, MA, USA, a wholly owned subsidiary of Takeda Pharmaceutical Company Limited: Employment. Lin:Millennium Pharmaceuticals Inc., Cambridge, MA, USA, a wholly owned subsidiary of Takeda Pharmaceutical Company Limited: Employment. Li:Millennium Pharmaceuticals Inc., Cambridge, MA, USA, a wholly owned subsidiary of Takeda Pharmaceutical Company Limited: Employment. Badola:Millennium Pharmaceuticals Inc., Cambridge, MA, USA, a wholly owned subsidiary of Takeda Pharmaceutical Company Limited: Employment. Shen:Millennium Pharmaceuticals Inc., Cambridge, MA, USA, a wholly owned subsidiary of Takeda Pharmaceutical Company Limited: Employment. Zhang:Millennium Pharmaceuticals Inc., Cambridge, MA, USA, a wholly owned subsidiary of Takeda Pharmaceutical Company Limited: Employment. Wang:Millennium Pharmaceuticals Inc., Cambridge, MA, USA, a wholly owned subsidiary of Takeda Pharmaceutical Company Limited: Employment. Esseltine:Takeda: Equity Ownership; Millennium Pharmaceuticals Inc., Cambridge, MA, USA, a wholly owned subsidiary of Takeda Pharmaceutical Company Limited: Employment; Johnson and Johnson: Equity Ownership. Luptakova:Takeda Oncology: Employment. van de Velde:Millennium Pharmaceuticals Inc., Cambridge, MA, USA, a wholly owned subsidiary of Takeda Pharmaceutical Company Limited: Employment. Richardson:Jazz Pharmaceuticals: Consultancy, Membership on an entity's Board of Directors or advisory committees. Moreau:Bristol-Myers Squibb: Honoraria; Takeda: Honoraria; Celgene: Honoraria; Janssen: Honoraria, Speakers Bureau; Novartis: Honoraria; Amgen: Honoraria.

Abstract Background: Myeloproliferative neoplasms (MPN) including polycythemia vera (PV), essential thrombocythemia (ET), and myelofibrosis (MF) are clonal hemopathies characterized by burdensome symptom profiles and impaired quality of life. Few studies have evaluated patient-reported outcomes during treatment with non-experimental pharmacological regimens. Aims: The Myeloproliferative Neoplasm Quality of Life (MPN-QOL) Study Group aims to objectively quantify MPN symptom severity, frequency and quality of life at baseline and throughout treatment with non-experimental therapies utilizing the Myeloproliferative Neoplasm Symptom Assessment Form - Total Symptom Score (MPN-SAF TSS; JCO 2012). In this abstract, we provide updated results for the prospective international cohort trial currently in active enrollment: the MPN Experimental Assessment of Symptoms by Utilizing Repetitive Evaluation (MEASURE) trial. Methods: This study aims to recruit 180 international ET, PV, and MF (including primary MF and post-ET or post-PV MF) patients receiving non-experimental medical therapy and/or phlebotomy. Patients complete the MPN-SAF for seven consecutive days at enrollment and repeat the survey for an additional seven consecutive days between 90 days and six months. Patients also complete the European Organisation for Research and Treatment of Cancer (EORTC) and M.D. Anderson Symptom Inventory (MDASI) instruments at enrollment and on the first day of the second assessment. At visits, physicians acquired demographic, laboratory, physical examination, and radiographic data. Descriptive statistics were used to summarize data. Results: Clinical Data The MEASURE trial opened for enrollment in 2012 and remains in recruitment phase with 15 participating international sites. To date, 39 patients have been enrolled and 25 have completed both study visits. Participants include ET (28%), PV (24%), and MF (48%; 50% primary MF, 8% post-ET, 42% post-PV) patients. The majority of patients are male (64%) and of expected age (mean 69.3, range 39-89) for the disorders. Seventeen percent had prior thrombosis, 9% required red blood cell transfusion, and none reported prior splenectomy or hemorrhage. Mean hematologic measures included hemoglobin 13.2 g/dL, WBC count 11.4 x109/L, ANC 8.5 x109/L, and platelets 514 x109/L. Therapies received prior to enrollment included aspirin (n=16), hydroxyurea (n=11), phlebotomy (n=8), warfarin/clopidogrel/anticoagulation (n=8), erythropoietin (n=2), and interferon (n=1). The most common current MPN therapies were hydroxyurea (n=9), aspirin (n=9), interferon (n=4), and phlebotomy (n=2). Symptom Assessment In comparing MPN-SAF TSS mean symptom scores, all symptoms except bony pain improved between the first and second visits, including fatigue, early satiety, abdominal discomfort, inactivity, concentration, night sweats, itching, fever, weight loss, and overall quality of life (Figure1). Total MPN-SAF TSS scores improved from a mean of 32.3 to 25.9. On the EORTC, mean scores for physical, role, emotional, and social functioning improved from the first to the second visit (Figure 2). Cognitive functioning showed a slight decline. Global health status measure improved from 60.2 to 72.9. On the MDASI, symptom severity scores decreased from 3.6 to 2.8 from the first to second visit (Figure 3). Symptom distress measure decreased from 4.1 to 3.0. Discussion: Interim results from the MEASURE trial demonstrate that standard, non-experimental treatment regimens offer improvement in quality of life-related symptoms on multiple patient-reported survey instruments including the MPN-SAF TSS, EORTC QLQ-C30, and MDASI. Updated data including symptom correlations and mutational analysis to be presented at the 2016 ASH conference. Disclosures Ross: Novartis Pharmaceuticals: Honoraria, Research Funding; BMS: Honoraria. Radia:Novartis: Honoraria; Pfizer: Honoraria. McMullin:Novartis: Honoraria, Speakers Bureau. Cargo:Novartis: Honoraria; Celgene: Honoraria, Research Funding. Sekhar:Novartis: Research Funding. Mesa:Gilead: Research Funding; CTI Biopharma: Research Funding; Galena: Consultancy; Ariad: Consultancy; Incyte: Research Funding; Novartis: Consultancy; Celgene: Research Funding; Promedior: Research Funding.

Abstract Integrins play fundamental roles in many biological processes such as development, immunity, cancer, wound healing, hemostasis, and thrombosis. Integrin activation is essential for cell adhesion, spreading, survival, proliferation, and migration. Integrins are heterodimeric transmembrane glycoproteins composed of a and b subunits. The function of integrins is modulated by bi-directional transmembrane signaling: inside-out and outside-in signaling, which are mediated through the interactions between integrin a or b subunit cytoplasmic tails and intracellular proteins and can be regulated by many different biochemical signaling pathways. αIIbβ3 is a major integrin expressed in megakaryocytes and platelets. Antagonists of αIIbβ3 are potent anti-thrombotic drugs and new inhibitors targeting αIIbβ3 are under preclinical testing or large patient trials to treat acute coronary syndromes. Integrin αIIbβ3 activation involves binding of proteins, including talin, kindlins, Src kinase, and Gα13 to the cytoplasmic domain of its β subunit. To gain insight into αIIbβ3signaling and to identify new proteins that regulate αIIbβ3 activation, agarose beads conjugated with glutathione S-transferase (GST)-β3 integrin cytoplasmic domain fusion protein (GST-β3CD) or GST-αIIb integrin cytoplasmic domain fusion protein (GST-αIIbCD) were incubated with human platelet lysates. Proteins pulled down by the GST-β3CD or GST-αIIbCD beads were subjected to mass spectrometric analysis. We found that the GST-β3CD but not the GST-αIIbCD beads specifically pulled down a previously unreported protein, the vacuolar protein sorting-associated protein 33B (VPS33B), encoded by the VPS33B gene. To verify that VPS33B is in a complex with αIIbβ3, we infected Chinese hamster ovary (CHO) cells stably expressing αIIbβ3 (A5 cells) with an adenovirus containing FLAG epitope-tagged human VPS33B cDNA. Cells were allowed to adhere and spread on fibrinogen. FLAG-VPS33B exhibited a significant intracellular colocalization with aIIbb3. Immunoblotting analysis revealed a specific association of b3 with precipitated FLAG-VPS33B. The specific interaction was also confirmed by reciprocal immunoprecipitation using a specific β3antibody. Furthermore, in an in vitro binding assay, we were able to pull down VPS33B from the lysates of CHO cells overexpressing VPS33B by the GST-β3CD beads. The interaction appears to be direct, since we were also able to pull down purified FLAG-VPS33B with GST-β3CD and GST-β1CD proteins. The pulldown assay showed that the β3 fragment spanning residues 716~730 bound efficiently to FLAG-VPS33B. In contrast, the fragments containing either residues 729~762 or residues 744~762 fragments failed to do the same. More importantly, using the rabbit polyclonal antibody against VPS33B, we were able to coimmunoprecipitate endogenous b3 subunit with VPS33B from human platelet lysate. Thus, we identified a novel binding protein of integrin β3. Next, we investigated the role of VPS33B in integrin activation using a recombinant integrin activation model of CHO cells. Overexpression of VPS33B in CHO cells expressing αIIbβ3 (A5 cells) markedly potentiated cell spreading on fibrinogen and F-actin formation. To establish a role of VPS33B in integrin activation in platelets, we created a mouse model with megakaryocyte- and platelet-specific deletion of VPS33B. Platelets lacking VPS33B were defective in spreading on fibrinogen. VPS33B-/- platelets failed to support clot retraction. On the other hand, thrombin-induced fibrinogen binding to platelets and platelet aggregation were not affected by the loss of VPS33B. Collectively, these results demonstrate an essential role of VPS33B in αIIbβ3 outside-in signaling but is not requried for integrin inside-out signaling. We further demonstrate that VPS33B promotes αIIbβ3 outside-in signaling through RhoA and Rac1 activation, leading to clot retraction and cell spreading, respectively. Therefore, our results for the first time establish vesicle trafficking proteins as an important novel class of modifiers of integrin function in platelets and cells. Disclosures No relevant conflicts of interest to declare.

Abstract Background: Numerous studies have shown that lymphoma B-cells are resistant to CTL-mediated death, however the underlying mechanism for this resistance is not clear. In previous work, we have identified a subset of CD4+CD25+ T-cells overrepresented in the tumor sites of B-cell NHL that display a phenotype compatible with regulatory T cells (Treg cells). These cells express high levels of Foxp3 and CTLA-4, and are capable of suppressing the proliferation and cytokine production of autologous infiltrating CD4+CD25- T cells in B-cell NHL. Goal: To explore whether Treg cells exert a suppressive effect on the induction and function of autologous tumor-infiltrating CD8+ T-cells in B-cell NHL. Results: Using fresh specimens obtained from patients with B-cell lymphoma, we found that intratumoral Treg cells had a significantly suppressive effect on autologous tumor-infiltrating CD8+ T-cells in B-cell NHL. When activated CD8+ T-cells were cocultured with infiltrating CD4+CD25- T-cells, they displayed less proliferation than CD8+ T-cells cultured alone. However, we found that with a 1:4 ratio of stimulating cells (Treg cells) to responding cells (CD8+ T-cells), intratumoral Treg cells completely inhibited the proliferation of autologous tumor-infiltrating CD8+ T-cells activated with PHA. Furthermore, we have observed that 20% of infiltrating CD8+ T-cells in fresh isolated samples from B-cell NHL coexpress perforin and granzyme B. When intratumoral Treg cells were cocultured with CD8+ T-cells, the Treg cells inhibited the activation-induced production of perforin and granzyme B of autologous tumor-infiltrating CD8+ T-cells in a dose-dependent fashion. We also found that cytokine treatment (IL-2 and IL-12) or PHA activation induced the capability of tumor-infiltrating CD8+ T-cells to kill lymphoma B-cells, which was accompanied by upregulation of expression of CD107a on the surface of cytotoxic CD8+ T-cells. Intratumoral Treg cells significantly inhibit cytotoxicity of activated infiltrating CD8+ T-cells to lymphoma B-cells. Finally, we found that there was an inverse correlation of cell frequencies between intratumoral Treg cells and tumor-infiltrating CD8+ T cells in patients with B-cell NHL, suggesting that Treg cells may inhibit the migration of cytotoxic T-cells to the sites of B-cell lymphoma. Conclusion: Intratumoral Treg cells dramatically suppress the proliferation and activation-induced production of granules in infiltrating CD8+ T-cells in B-cell NHL. These Treg cells also inhibit the ability of activated tumor-infiltrating CD8+ T-cells to kill lymphoma B-cells in vitro, and may prevent the migration of CD8+ cells to the sites of lymphoma. Taken together, these data indicate an important role for intratumoral Treg cells in CTL-mediated anti-tumor immunity in B-cell NHL.

Abstract Cell development requires tight yet dynamic control of protein production. Here, we use murine erythropoiesis as a model to study translational regulatory dynamics during mammalian cell differentiation. We uncover pervasive translational control of protein synthesis, including widespread alternative translation initiation and termination, stoichiometric synthesis, and dynamic use of upstream reading frames. In addition, we identify hundreds of mRNAs with dynamic translation efficiencies during erythropoiesis. Interestingly, these mRNAs have significantly enriched binding motifs of many mRNA-binding proteins that are expressed with high specificity in hematopoietic cells, suggesting that those mRNA-binding proteins are important players in the translational regulatory programs in erythropoiesis. A major such program involves enhanced decoding of specific mRNAs depleted in terminally differentiating/enucleating cells with decreasing transcriptional capacity. We functionally characterized one such protein, Rbm38, which was previously identified as a splicing factor in terminal erythropoiesis, can enhance the translation of a subset of those mRNAs by interacting with the general translation initiation factor eIF4G in erythroid cells. Altogether, our findings reveal widespread and dynamic translational control in supporting specialized mammalian cell formation. Disclosures No relevant conflicts of interest to declare.

Abstract Background: Immune editing is a major mechanism used by tumors to promote its survival. We have reported previously the presence of a novel phenotype of immunosuppressive monocytes (CD14+HLA-DRlow/neg) in a number of cancers. Increased presence of these cells was associated with decreased treatment response and OS. We have demonstrated that certain tumor cells can convert normal CD14+HLA-DR+ monocytes to CD14+HLA-DRlow/neg phenotype in an IL-10 independent and a tumor specific way. These CD14+HLA-DRlow/neg monocytes, in turn, protect tumors from cytotoxic killing from chemotherapy. Here we report up-regulation of heat shock protein-27 (HSP27) as one mechanism mediating this effect. Method: Monocytes from healthy donors were co-cultured with lymphoma cell lines (OCI-Ly3, Jeko-1, and Granta-519) with or without doxorubicin (DOX). Cultured cells were assessed for phenotype, viability and proliferation by flow cytometry. Lymphoma cells were isolated with anti-CD19 immunomagnetic beads and assayed by immunoblot for expressions of proteins regulating apoptosis. HSP27 levels in human plasma were measured by ELISA. Results: DOX incubation induced apoptosis and decreased viability of all three cell lines; and co-culture with monocytes improved the lymphoma cell survival (for example, untreated Granta-519 had a 2.1±0.45 fold expansion, that was reduced to 0.39±0.12 when treated with DOX and 0.81±0.27 after co-culture with monocytes with DOX. p<0.05, n=11.) Co-culture with monocytes induced increased HSP27 expression in lymphoma cells. HSP27 levels were further increased in co-culture with monocytes and DOX, with corresponding decrease in cleaved Caspase-3 levels. As tumor cells can secrete HSP27, we found detectable levels of HSP27 in plasma of lymphoma patients. Increased HSP27 in plasma correlated with increased proportion of CD14+HLA-DRlow/neg monocytes in blood. Conclusions: We have found that monocytes may promote lymphoma resistance to DOX killing by inducing increased HSP27. In turn, HSP27 from lymphoma patients may induce immune suppressive phenotype in monocytes. Together, this data demonstrates an active cross talk between monocytes and lymphoma resulting in multiple mechanisms of tumor resistance to chemo-immunotherapy. Disclosures No relevant conflicts of interest to declare.

Abstract Background We have previously reported on the high prevalence and severity of challenges with intimacy and sexuality amongst a large international cohort of MPN patients (Emanuel JCO 2012). We sought to further analyze the relationships between issues of intimacy (sexual desire and function), their relationships to MPN disease features, individual MPN symptom prevalence and severity, language, and overall quality of life. Methods Data was collected among an international cohort of patients with MPNs. Subjects completed the BFI, MPN-SAF, and EORTC QLQ-C30 instruments. Surveyed symptoms on the MPN-SAF included the patient’s perceptions of common MPN-related symptoms and overall quality of life (QOL) on a 0 (absent) to 10 (worst imaginable) scale. Specifically, the MPN-SAF sexuality item asked about “problems with sexual desire or function”. Total symptom score (TSS) was computed based on 10 symptom items using the published scoring algorithm on a 0 (all reported symptoms absent) to 100 (all reported symptoms worst imaginable) scale. Pairwise associations between the MPN-SAF sexuality item and continuous and categorical covariates were investigated using Pearson correlations and analysis of variance/t-tests, respectively. Multivariate regression models were used to investigate impact of groups of covariates on the sexuality item with the final multivariate model selected using forward regression. Results Demographics A total of 1908 MPN patients (essential thrombocythemia=799, polycythemia vera=671, myelofibrosis=432, missing=6) completed the sexuality item. Participants were of typical age (median=60, range 15-94) and gender (female=53%). Overall, 1218 subjects described sexuality related complaints (score >0) with an overall mean symptom score of 3.5 (median=2.0, SD=3.7, range 0-10); 725/1908 (38%) patients had severe sexuality related complaints (score >4). Univariate Analysis Among the QLQ-C30 functioning scales, all domains had similar statistically significant correlations (r=-.26 to -.32, all p<0.001). Among QLQ-C30 symptom scales, all QLQ-C30 symptoms displayed correlations ranging between .08 and .29 (all p<0.001). Among MPN-SAF items, the MPN-SAF sexuality item correlated most significantly with the TSS (r=.41, p<0.001), along with MPN-SAF symptoms (r=.16 to .39; all p<0.001). MPN-SAF sexuality measure significantly differed by anemia (means: absent 3.3, present 4.5; p<0.001), leukopenia (means: absent 3.4, present 4.4; p=0.01), thrombocytopenia (means: absent 3.3, present 4.5; p<0.001), red cell transfusion (means: no 3.5, yes 5.0; p<0.001), MPN subtype (ET mean 3.1, PV mean=3.6, MF mean=4.4; p<0.001) and language (means ranged from 2.4 [Swedish] to 4.6 [Chinese]; p<0.001). MPN-SAF sexuality did not significantly differ by age, gender, prior thrombosis or prior hemorrhage. Multivariate Analysis In a multivariate model of MPN-SAF sexuality containing all QLQ-C30 functioning scales, physical (p=0.001), emotional (p=0.01), cognitive (p=0.005) and social (p=0.002) functioning were all statistically significant. Numerous symptoms were also significant in a multivariate model of MPN-SAF sexuality containing all other MPN-SAF symptoms (all p<0.05; abdominal pain, inactivity, dizziness/vertigo/lightheadedness, insomnia, depression/sad mood, cough, night sweats and overall QOL). The final multivariate model based on forward regression starting with all demographics, clinical variables, and patient-reported QLQ-C30 scales and MPN-SAF items found age, language, QLQ-C30 role functioning and MPN-SAF items (insomnia, depression/sad mood, night sweats and QOL) to be significant (p<0.05). Conclusions Sexuality related complaints have been linked to both physiologic and psychologic origins and are highly prevalent within the MPN population. The results of this study congruently identified close associations between sexuality and function within emotional, cognitive and social domains. Additionally, the correlations of sexuality issues with MPN symptoms and disease features further suggest this item is a key correlate of overall functionality and quality of life. Future investigations into the causative factors and biological correlates of this complaint may assist in addressing this ongoing challenge. Disclosures: Etienne: novartis: Consultancy, Membership on an entity’s Board of Directors or advisory committees; Bristol Myers Squibb: Consultancy, Membership on an entity’s Board of Directors or advisory committees; Pfizer: Membership on an entity’s Board of Directors or advisory committees; Ariad: Membership on an entity’s Board of Directors or advisory committees. Roy:Novartis, BMS: Honoraria. Harrison:Novartis: Honoraria, Membership on an entity’s Board of Directors or advisory committees, Research Funding, Speakers Bureau; Sanofi: Honoraria, Membership on an entity’s Board of Directors or advisory committees, Speakers Bureau; YM Bioscience: Honoraria, Membership on an entity’s Board of Directors or advisory committees; Celgene: Honoraria; Shire: Speakers Bureau; S Bio: Honoraria, Membership on an entity’s Board of Directors or advisory committees; Gilead: Honoraria, Membership on an entity’s Board of Directors or advisory committees. Birgegard:Vifor Pharma: Honoraria. Mesa:Eli Lilly and Co: Research Funding; Genetech: Research Funding; Gilead: Research Funding; Incyte: Research Funding; Sanofi: Research Funding; NS pharma: Research Funding; Celgene: Research Funding.

Abstract Introduction: CLL is the most prevalent leukemia in the United States (≥120,000 cases) with approximately 5000 deaths per year. The dominant cause of mortality in CLL patients is serious infection. Indeed, about 80% of CLL patients will sustain infectious complications at some point during their disease course and infection risk increases with length of the disease. Steady-state hematopoiesis in BM is required to sustain a peripheral repertoire of blood cells and maintain immune competence. There have been few studies evaluating the hematopoietic capacity of CLL BM and how it may relate to immune competence. Thus, the goal of this study was to determine the status of BM hematopoiesis in untreated and treated CLL patients. Methods and findings: The hematopoietic stem (HSC) and progenitor cell pool (HSPC) in human BM is defined by expression of CD34 and lack of surface markers (Lin-) expressed on their mature progeny. Frequencies of Lin- CD34+ progenitors in BM between age matched healthy subjects (HS) (n=22) and untreated CLL patients (n=10) were compared. We note that the Lin+ cocktail used included an antibody to CD19, eliminating dilution of CD34+ HSPC frequency due to variation in leukemic B cell infiltration. CD34+ HSPCs were significantly reduced in untreated CLL patients (6.33±3.01% vs. 2.04±2.33% in HS vs. CLL, p=0.0004). Next we evaluated total CFU responding cells within the residual CD34+ cells to determine if they were functionally compromised. Numbers of total CFU-responsive CD34+ progenitors (CFU-GM, CFU-E, and CFU-GEMM) were reduced when assayed from purified CLL patient CD34+ cells compared to HS. Thus, while HSPC are present in CLL patient BM, they are functionally compromised even after removal from the tumor microenvironment. To determine if reductions in CFUs were accompanied by decreased myeloid and erythroid lineage differentiated progeny, we evaluated frequencies and absolute numbers of CD14+ monocytes and CD71+ erythroid progenitors by flow cytometry and found both were severely reduced in CLL patient BM. To determine if the reductions in myeloid/erythroid lineage cells was due to deficiencies in their precursor HSPCs, we evaluated frequencies and absolute numbers of HSC, multipotent progenitors (MPP), and common myeloid progenitors (CMP). Proportions, but not absolute numbers, of HSC, MPP, and CMP were significantly reduced in CLL patient BM. Frequencies of CD14+ monocytes and CD71+ erythroid precursors were also significantly reduced in patients with low BM tumor burden (designated as 20-40% BM involvement), suggesting that the hematopoietic dysfunction is not solely due to tumor burden. Comparative analysis of frequencies of CD14+ monocytes in BM to frequencies of monocytes in peripheral blood revealed a strong association, suggesting that for some immune cell types the blood immune repertoire may be reflective of BM dysfunction. In addition to BM evaluation of untreated CLL patients, we also studied a cohort of post-therapy patients (n=23). Not surprisingly, we found considerable heterogeneity in the extent of BM hematopoietic reconstitution. Nevertheless, we observed robust BM hematopoiesis post therapy in a subset of treated patients (n=9 of 23). Summary: Our findings reveal BM hematopoietic dysfunction (HD) in CLL not solely due to the degree of tumor burden. Importantly, the BM HD is reversible by effective therapies. The HD is manifested by reduced numbers and function of HSPCs and production of their mature progeny. Of significance is the severe reduction in monocytic and granulocytic cells found in CLL BM. This is an important finding as these two innate cell types provide critical first responder protection against invading pathogens. Our study also uncovered that levels of blood monocytes can mirror their diminished production in BM. Future studies will focus on determining the mechanism(s) that reduce the ability of CLL BM to sustain immune cell production in addition to determining if restoration of hematopoiesis is a necessary outcome for more effective therapies. Disclosures Ding: Merck: Research Funding. Kay:Pharmacyclics: Research Funding; Tolero Pharmaceuticals: Research Funding; Acerta: Research Funding; Gilead: Membership on an entity's Board of Directors or advisory committees; Morpho-Sys: Membership on an entity's Board of Directors or advisory committees; Infinity Pharm: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees.

Abstract Introduction: Despite recent advances in available treatments, chronic lymphocytic leukemia (CLL) remains an incurable disease, and the vast majority of patients (pts) will relapse and require additional lines of therapy. Thus, prolonging remission is a key treatment goal in CLL. This multicenter, randomized, double-blinded phase 3 trial (NCT00774345) was designed to evaluate the efficacy and safety of lenalidomide (LEN) vs placebo (PBO) as maintenance therapy in previously treated CLL pts. Methods: Eligible CLL pts must have had at least a partial response (PR) to second-line therapy. Pts were randomized 1:1 to receive either LEN 2.5 mg once daily on days 1-28 of the first 28-day cycle, or matching PBO. If LEN was well tolerated, escalation to 5 mg/day was permitted from cycle 2, and further escalation to 10 mg/day at cycle 7 and thereafter. Pts were stratified by their response at the end of second-line therapy (PR, nodular PR, complete response [CR], or CR with incomplete bone marrow recovery; vs minimal residual disease [MRD]-negative CR by flow cytometry); age (≤ 70 vs > 70 years); and presence of at least one of the following poor prognostic factors: del(11q), del(17p), unmutated IGHV, or b2M > 0.4 mg/L (Yes vs No vs Unknown). Co-primary endpoints were progression-free survival (PFS; IRAC assessed) and overall survival (OS). Secondary endpoints included: safety, tumor response, duration of response, second PFS (PFS2, time from randomization to second disease progression or death), and health-related quality of life (HRQoL). Results: Overall, 314 pts were enrolled (LEN, n = 160; PBO, n = 154). Baseline characteristics were balanced between the treatment arms: median age was 63 years (range 37-82) and 63 years (range 37-84), 71.9% and 72.1% were male, 9.4% and 11.7% had MRD-negative CR to second-line treatment, and 47.5% and 47.4% had at least one poor prognostic factor, in the LEN and PBO arms, respectively. On review of the primary analysis, 30 Sept 2015 data cutoff, the required number of progression events to complete the co-primary analysis had occurred, and the data monitoring committee recommended that the study be unblinded. Median follow-up time was 31.5 months, and the median PFS was significantly longer for LEN vs PBO: 33.9 vs 9.2 months, respectively (HR 0.40 [95% CI 0.29, 0.55]; P < 0.001). At the time of the analysis there were 86 deaths and there was no significant difference in the OS (HR 0.96 [95% CI 0.63, 1.48]; P = 0.856). Subsequent CLL therapy was received by 35.7% of pts in the LEN arm and 58.4% of pts in the PBO arm, of these pts 16% in the LEN arm and 20% in the PBO arm were treated with a BTK or PI3K inhibitor. Median PFS2 was significantly longer for LEN vs PBO: 57.5 vs 32.7 months, respectively (HR 0.46 [95% CI 0.29, 0.70]; P <0.001). Median number of treatment cycles received was 18 vs 9 cycles, for LEN vs PBO, respectively; a higher proportion of pts in the LEN arm started ≥25 cycles vs the PBO arm (38.9% vs 24.0%, respectively). Median dose intensity in the LEN arm was 4.2 mg/day. The most common adverse events (AEs) of all grades were neutropenia (66.2% vs 30.5%) and diarrhea (40.8% vs 16.2%) in the LEN vs PBO arm, respectively. Febrile neutropenia occurred in 1.9% vs 0%, deep vein thrombosis in 1.9% vs 0%, and pulmonary embolism in 2.5% vs 0.6% of pts in the LEN vs PBO arm, respectively. Most common grade 3/4 AEs were neutropenia (59.9% vs 22.7%), thrombocytopenia (16.6% vs 6.5%), and diarrhea (8.3% vs 0.6%) in the LEN vs PBO arm, respectively; all other grade 3/4 AEs occurred in <5% of pts in either arm. While there was a significant difference in the incidence of neutropenia, the rate of grade 3/4 infections was 16.6% for LEN vs 10.4% for PBO-treated pts. There were 13 (8.3%) vs 14 (9.1%) pts with at least one invasive second primary malignancy (SPM) in the LEN vs PBO arm, respectively. Hematologic invasive SPMs occurred in 7 vs 2 pts, and solid tumor invasive SPMs occurred in 7 vs 12 pts, in the LEN vs PBO arm, respectively. Overall, 44 pts in the LEN arm and 41 pts in the PBO arm died; 1 pt died on treatment in the LEN arm, and 2 pts in the PBO arm. There was no clinically meaningful difference in HRQoL for LEN vs PBO, as measured by FACT-Leu and EQ-5D, during maintenance treatment. Conclusions: LEN maintenance therapy significantly improved PFS from 9.2 to 33.9 months following second-line treatment in pts with CLL. The incidence of invasive SPMs was similar in both arms, and LEN maintenance treatment had an expected and acceptable safety profile. Disclosures Foà: Roche: Consultancy, Speakers Bureau; Janssen: Speakers Bureau; Gilead,: Consultancy, Speakers Bureau; Amgen: Consultancy, Speakers Bureau; Celgene Corporation: Consultancy, Speakers Bureau; Pfizer, Ariad: Speakers Bureau; Genentech, Janssen, BMS: Consultancy. Schuh:Gilead: Consultancy, Honoraria, Research Funding; Roche, Janssen, Novartis, Celgene, Abbvie: Consultancy, Honoraria. Zaritskey:Novartis: Consultancy; Janssen: Consultancy. Semochkin:Celgene, Sandoz, Novartis, Astellas, Janssen Pharmaceuticals, Bristol-Myers Squibb: Speakers Bureau; Celgene, Bayer Healthcare, Astellas Pharma Inc.: Research Funding; City Clinical Hospital 52, Moscow, Russia: Consultancy. Simpson:Amgen Pharmaceuticals: Research Funding; Celgene, Roche, Janssen: Honoraria. Vokurka:Roche: Consultancy, Honoraria; Takeda: Consultancy, Honoraria. Zhang:Celgene Corporation: Employment, Equity Ownership. Purse:Celgene Corporation: Employment, Equity Ownership.

Abstract Introduction: Immune suppression is a major component of lymphoma pathogenesis. Recent advances in lymphoma treatment have been immunotherapy. We present the preliminary results of our clinical trial testing 2 vaccine strategies in patients with indolent B-cell non-Hodgkin lymphoma (NHL). The primary objective is to determine the safety and feasibility of the vaccine approaches and secondary objectives are to describe clinical responses and identify corresponding immune changes. Methods: Autologous mature dendritic cells (mDC) were manufactured from leukapheresed cells of NHL pts. For patients with tumor lymph nodes deemed amenable to cryoablation by interventional radiologist (arm A), they received cryoablation of a node and injection of mDC into the cryoablated node followed by another 1 to 7 intratumoral mDC injections. Remaining patients had a tumor excised to generate tumor lysate ex vivo. mDC were pulsed with tumor lysate during DC maturation (arm B; DC-TL). The DC-TL vaccines were injected intradermally for 4 to 8 doses. Patients are monitored for one year after vaccines for adverse events and systemic tumor response. Correlative studies include cellular immune phenotype of peripheral blood and T cell intracellular cytokine productions. Planned accrual is 10 patients per arm (total = 20). Results: To date, 10 patients have accrued to arm A and 5 patients to arm B (Table 1). All pts tolerated vaccine treatments without major adverse events. Of the 10 evaluable patients, there were 1 CR (arm B: 1 / 4; total: 1/6) and 4 PR (arm A: 3/6; arm B: 1 / 4; total: 4/10) for an ORR of 50% for both arms (Figure 1). Time to next treatment ranged from 6.5 to 25 months (Figure 2). Correlative studies suggest that immune changes can be used as prognostic biomarkers to predict response. These include changes in vaccine induced cytokine secretion, and in the number and composition of the immune system. In addition, preliminary analysis of >40 immune phenotypes using flow cytometry and hierarchical clustering suggest there are characteristic immune system responses in patients responding to vaccine. Conclusions: Both cryoablation and intratumoral mDC vaccination are feasible and safe in NHL. Treatment responses may correlate with immune system changes. Biosystems analysis method can be used to develop novel assays as predictive biomarkers of treatment response and used to develop novel protocols that allow treating to response. Table 1. Patient Demographics Arm A (n = 10) Arm B (n = 5) Total (n = 15) Age (median, rage) 64 (55 – 80) 60 (31 – 86) 63 (31 – 86) Gender (M/F) 6/4 2/3 8/7 Histology (n, %) Follicular Marginal zone DLBCL 10 (100%) 0 (0%) 0 (0%) 3 (60%) 1 (20%) 1(20%) 13 (86.6%) 1 (6.7%) 1 (6.7%) Stage (N, %) II III IV 1 (10%) 1 (10%) 8 (80%) 2 (40%) 1 (20%) 2 (40%) 3 (20%) 2 (13.3%) 10 (66.7%) No of prior Tx (mean, range) 2.4 (0-8) 3.2 (0-7) 2.7 (0-8) FLIPI (n, %) 0-1 2 ≥ 3 1 (10%) 2 (20%) 7 (70%) 1 (20%) 2 (40%) 2 (45%) 2 (13.3%) 4 (26.7%) 9 (60%) Positive GELF criteria (n, %) 4 (40%) 1 (20%) 5 (30%) Figure 1. Waterfall plot. Figure 1. Waterfall plot. Figure 2. Time to next treatment. Figure 2. Time to next treatment. Disclosures No relevant conflicts of interest to declare.