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Introduction: Non-endemic Burkitt lymphoma (BL) is a rare and highly aggressive B-cell malignancy, of whom a substantial number are adolescents and young adults (AYAs). In this particular group of patients, the balance between efficacy and long-term toxicities is of major concern, due to the long expected remaining lifetime. In this study, we investigated the outcomes for AYA patients treated with intensive immunochemotherapy. Patients and methods: Patients were identified through queries to clinic based and population-based lymphoma registries from six countries (Australia, Canada, Denmark, Norway, Sweden, and USA). All diagnoses were confirmed by local investigators; patients with classical BL histology plus detectable MYC translocation, were included. Patients between 18 and 39 years of age at diagnosis treated with intensive immunochemotherapy (DA-EPOCH-R or more intensively) were evaluated in pre-specified age groups. All treatment protocols included rituximab. Overall survival (OS) was defined as the time from diagnosis until death from any cause or censoring, while event-free survival (EFS) was defined as the time from diagnosis until unplanned re-treatment, progression/relapse, death, or censoring, whichever came first. Response evaluation was assessed using established response criteria based on CT and/or PET/CT imaging. Survival curves were computed using the Kaplan-Meier estimator. The cumulative incidence of relapse in patients reaching complete remission (CR) or CR unconfirmed (CRu) was computed by Aalen-Johansen estimator. The 5-year restricted loss of lifetime (RLOL) was defined as the area between the patient and general population survival curves until 5-years. The general population survival was retrieved from publicly available lifetables stratified on age, sex, calendar year, and country. Results: In total, 108 AYA BL patients were included. The median age was 30 years, ranging between 18 and 39 and 82% were male. The majority had advanced stage disease (Ann Arbor stage III-IV, 76%), extranodal involvement (87%), and elevated LDH (67%). Seven patients (6%) had CNS involvement at the time of diagnosis. The chemotherapy regimens used were CODOX-M/IVAC (51%), BFM/GMALL (34%), hyper-CVAD (7%), DA-EPOCH (5%), and others (3%). Among 74 patients for whom data on tumor lysis were available, 10 (14%) developed clinical tumor lysis upon start of chemotherapy, all presenting with advanced stage and extranodal disease. The response rate was 91% (89 in CR/CRu and 2% in partial remission). At a median follow-up of 53 months, 15 had an event and 10 died. The 2-year OS and EFS for the total population was 92% (87-97%, Figure 1) and 88% (82-94%), respectively. For 13 patients aged 18-21 2-year OS and EFS were both 100%, while 2-year OS and EFS for 43 patients aged 22-30 were 98% (93-100%) and 93% (85-100%), respectively. The 2-year OS and EFS for patients aged 31-39 were 86% (76-96%) and 80% (69-91%), respectively. For patients in CR/CRu and available date of response evaluation, the 2-year post-remission OS was 99% (97-100%) and the 2-year relapse risk was 2% (0-5%), with no relapses after 6 months. Compared to the general population, the RLOL was 0.8 months (-0.5-2.2 months). Nine patients did not respond to primary treatment (SD or PD), all which belonged to the age group 31-40 years (P<0.001 versus age group 18-30 years). The oldest age group had an inferior OS compared to younger patients (P=0.008), largely due to non-responders having poor subsequent survival with a 1-year OS of 33%. Conclusion: The outcomes of AYA BL patients following intensive immunochemotherapy are excellent with high remission rates and low risk of relapse in general. However, even among young patients age remained prognostic, with patients 31 years or older having inferior OS and lower response rate to first-line treatment. In patients achieving CR, survival was similar to that of the general population over the median follow-up of 4.5 years, illustrating the need to focus on survivorship issues in these individuals. Figure 1: Overall survival for BL patients following intensive immunochemotherapy for all patients and for age groups (18-21, 22-30, and 31-39 years). Figure 1 Disclosures Jørgensen: Gilead: Membership on an entity's Board of Directors or advisory committees; Roche: Membership on an entity's Board of Directors or advisory committees. Holte:Novartis: Honoraria, Other: Advisory board. Molin:Roche Holding AG: Honoraria; Merck & Co., Inc.: Honoraria; Bristol-Myers Squibb: Honoraria; Takeda Pharmaceuticals: Honoraria. Ekstroem Smedby:Takeda: Honoraria, Other: Grant funding, Research Funding; Celgene: Honoraria, Other: Grant funding, Research Funding; Janssen Cilag: Honoraria, Other: Grant funding, Research Funding. Song:Takeda: Honoraria; Celgene: Honoraria, Research Funding; Janssen: Honoraria; Amgen: Honoraria. Gerrie:Lundbeck, Seattle Genetics: Consultancy, Honoraria. Cheah:Roche, Janssen, MSD, Gilead, Loxo Oncology, Acerta, BMS: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Roche: Other: Travel expenses; Celgene, Roche, Abbvie: Research Funding. El-Galaly:Roche: Employment, Other: Travel support; Takeda: Other: Travel support.

Background Poly(adenosine diphosphate ribose) polymerase (PARP) inhibitors exhibit promising activity against ovarian cancers, but their efficacy can be limited by acquired drug resistance. This study explores the role of autophagy in regulating the sensitivity of ovarian cancer cells to PARP inhibitors. Methods Induction of autophagy was detected by punctate LC3 fluorescence staining, LC3I to LC3II conversion on Western blot analysis, and electron microscopy. Enhanced growth inhibition and apoptosis were observed when PARP inhibitors were used with hydroxychloroquine, chloroquine (CQ), or LYS05 to block the hydrolysis of proteins and lipids in autophagosomes or with small interfering RNA against ATG5 or ATG7 to prevent the formation of autophagosomes. The preclinical efficacy of the combination of CQ and olaparib was evaluated with a patient‐derived xenograft (PDX) and the OVCAR8 human ovarian cancer cell line. Results Four PARP inhibitors (olaparib, niraparib, rucaparib, and talazoparib) induced autophagy in a panel of ovarian cancer cells. Inhibition of autophagy with CQ enhanced the sensitivity of ovarian cancer cells to PARP inhibitors. In vivo, olaparib and CQ produced additive growth inhibition in OVCAR8 xenografts and a PDX. Olaparib inhibited PARP activity, and this led to increased reactive oxygen species (ROS) and an accumulation of γ‐H2AX. Inhibition of autophagy also increased ROS and γ‐H2AX and enhanced the effect of olaparib on both entities. Treatment with olaparib increased phosphorylation of ATM and PTEN while decreasing the phosphorylation of AKT and mTOR and inducing autophagy. Conclusions PARP inhibitor–induced autophagy provides an adaptive mechanism of resistance to PARP inhibitors in cancer cells with wild‐type BRCA, and a combination of PARP inhibitors with CQ or other autophagy inhibitors could improve outcomes for patients with ovarian cancer.

Abstract Background: Non-endemic Burkitt lymphoma (BL) is a rare B-cell malignancy characterized by extreme tumor proliferation, frequent extranodal involvement, and the genetic hallmark of a MYC gene rearrangement. Despite an often dramatic initial presentation featuring tumor compression of vital organs and/or spontaneous tumor lysis syndrome, most patients who survive intensive immunochemotherapy induction are cured. Despite limited evidence of benefit, the current NCCN guidelines recommend that BL patients in CR are reviewed every 3 months for 2 years and every 6 months thereafter. Aims: To investigate outcomes, including relative survival and relapse risks conditional on event-free survival (EFS) milestones, in an international study of real-world BL patients treated with intensive immunochemotherapy. Patients and methods: This is a retrospective study of newly diagnosed BL patients identified from relevant population or hospital-based registers in Australia (Perth), Denmark (the Danish Lymphoma Registry), Sweden (the Swedish Lymphoma Registry) and Norway (Health Region South East). Patients who met the following criteria were included irrespective of HIV status: 1) age ≥18 years at diagnosis, 2) diagnosed during the period 2005-2017, 3) histology and immunohistochemistry consistent with BL, 4) MYC translocation detected by fluorescence in situ hybridization (FISH), and 5) intensive first line immunochemotherapy including rituximab (R-CHOEP or more intensive). Patient data were collected from registers and chart reviews. Overall survival (OS) was defined as time until death and EFS was defined as time to death, relapse/progression, or unplanned treatment, whichever came first. Prognostic features at baseline were evaluated using univariate Cox models with EFS as outcome. Standardized mortality ratios (SMRs), conditional relative survival estimates, and relapse risks were computed for the subset of patients achieving complete remission (CR or CRu), with follow-up measured from response evaluation and from different EFS milestones. Results: In total, 159 patients fulfilled the inclusion criteria of the study. The median age was 48 years (range 18-81) and the male:female ratio was 2.9. The baseline characteristics included stage III-IV (75%), elevated serum LDH (75%), extranodal involvement (83% - bone or bone marrow in 42% and CNS in 8%), B symptoms (60%), and ECOG performance score >1 (30%). The chemotherapy protocols used were CHOEP (2%), DA-EPOCH (13%), HYPER-CVAD (26%), CODOX-M/IVAC (28%), BFM or GMALL (31%), and others (1%). Clinical tumor lysis syndrome defined by severe electrolyte derangement, renal impairment, and/or cardiac arrhythmia, was noted in 16% of the patients, but no fatal episodes occurred. The overall response rate to first-line treatment was 88% (87% in CR/CRu) with 67% assessed by PET technology. The five-year EFS and OS estimates for the total population were 75% (95% CI 68-82%) and 82% (95% CI 76-88%), respectively, and the EFS and OS of patients <50 years of age were 81% (95% CI 71-90%) and 89% (95% CI 82-96%), respectively. In univariate analyses, age, advanced stage, and elevated LDH were associated with worse EFS. Among patients in CR/CRu (n=137), the 5-year EFS and OS from the time of response evaluation were 86% (95% CI 79-93%) and 91% (95% CI 86-96%), respectively. The 5-year cumulative incidence of relapse from the time of response assessment was 5% (95% CI 1-9%) in CR/CRu patients. The corresponding estimate was 3% (95% CI 0-6%) for patients alive after 6 months without events (EFS6), whereas no patients relapsed after 12 (EFS12, Figure 1). For CR/CRu patients, the 5-year relative survival after EFS6 and EFS12 was 97% (95% CI 93-102%) and 100% (95% CI 97-103%), respectively. In most subgroups, the SMRs gradually decreased with increased remission duration (Table 1). Conclusions: Outcomes of adult BL patients treated with intensive immunochemotherapy are excellent with no relapses occurring for patients reaching EFS12 and with a normalized relative survival after EFS6. For patients reaching EFS12, follow-up in late effects clinics, or discharging to primary care providers with a focus on survivorship issues rather than detection of recurrent lymphoma, should be considered. Updated analyses including patients from British Columbia (Canada) and the University of Iowa/Mayo Clinic SPORE MER register (USA) will be presented at the meeting. Disclosures Molin: Takeda Pharmaceuticals: Research Funding; Bristol-Myers Squibb: Honoraria; Roche Holding AG: Honoraria; Merck & Co., Inc: Honoraria. Ekstroem Smedby:Janssen Pharmaceuticals: Other: The Department have recieved partial funding from Janssen Pharmaceuticals.

Abstract KaLwRij/C57Bl (KaLwRij, “Kal-ridge”) is a spontaneous mutant mouse strain predisposed to monoclonal gammopathy of uncertain significance (MGUS) and parallels many features of human pathology including progression to multiple myeloma (MM). In African Americans, an increased prevalence of MM is due to an increased risk of MGUS development (rather than increased rate of progression from MGUS) and is likely therefore mediated by germline MGUS risk alleles. In both humans and mice, the genetic basis for MGUS/MM risk is unknown. We sought to identify the genetic basis for MGUS/MM risk in KaLwRij mice to shed light on genes or pathways that might mediate risk in humans. We employed a novel integrative computational analysis, combining KaLwRij/B6 modified haplotype block analysis and low-power human MM/control single nucleotide polymorphism (SNP) data. We used high-density SNP arrays to establish genetic distances of KaLwRij from 11 another diverse inbred strains and confirmed close homology to parent C57Bl/6. Haplotype block analysis identified genetic loci that diverged from C57Bl/6 and included over 500 genes. We filtered the haplotype list using previously published RNA expression data from the bone marrow of C57Bl/6 and KaLwRij mice, to identify 71 differentially expressed genes. As a final filter, we used SNP data from a genome wide association study (GWAS) of human Caucasian MM case and normal volunteer samples (∼300 each) to identify SNPs differentially represented in MM patients. Combining these sets yielded four (4) candidate genes. Our top candidate, Samsn1 (Hacs1), is a negative regulator of B-cell activation and interestingly, was first identified as a gene differentially expressed in MM. Strikingly, we found that KaLwRij mice had a complete germline deletion of the Samsn1 gene. Samsn1 is expressed within the hematopoetic compartment, including B-cells, macrophages, and osteoclasts (OC), key cell types that participate in MM pathology. Consistent with the reported inhibitory function of SAMSN1, KaLwRij had enhanced naïve B-cell response and constitutive Lyn phosphorylation. Further, we found that KaLwRij macrophages and OC also have constitutive Lyn activation consistent activation of cytokine signaling pathways in stromal cells. Absence of Samsn1 may lead to unregulated B-cell and macrophage/OC activation, priming both a pro-tumor bone microenvironment and B-cells for development of MGUS and predisposition to MM. Our approach focused on germline loci rather than malignant cell genetic alterations, advancing our understanding of host predisposition. Identification of the gene or genes predisposing patients to MGUS/MM will provide novel targets for identifying at-risk individuals and will potentially allow the develop of preventative therapeutics for MM. Disclosures: No relevant conflicts of interest to declare.

Abstract Background: Peripheral T-Cell lymphomas (PTCLs) constitute approximately 10% of lymphoid malignancies and consist of several distinct entities based on pathologic and clinical characteristics. With the exception of a few subtypes (e.g., ALK-positive anaplastic large cell lymphoma (ALCL) and some primary cutaneous or leukemic forms of PTCL), a majority of PTCLs are aggressive as characterized by poor treatment response, rapid disease progression and poor overall survival. We have shown that landmark timepoints of event-free survival after diagnosis can stratify subsequent overall survival (OS) in diffuse large B-cell and follicular lymphoma. Here we evaluate this approach in newly diagnosed aggressive PTCLs treated with anthracyline-based or related chemotherapy. Methods. Newly diagnosed PTCL patients were prospectively enrolled in the University of Iowa/Mayo Clinic Lymphoma SPORE Molecular Epidemiology Resource (MER) from 2002-2012. Clinical data were abstracted from medical records using a standard protocol. For this analysis, we included patients receiving anthracycline-based or other multiagent chemotherapy for the following PTCL subtypes: ALK-negative ALCL (N=24); angioimmunoblastic T-cell lymphoma (AITL, N=34); PTCL, not otherwise specified (NOS; N=60); enteropathy-associated T-cell lymphoma (EATL, N=8); extranodal NK/T-cell lymphoma, nasal type (ENKTL, N=11); and hepatosplenic T-cell lymphoma (HSTCL, N=1). Patients were prospectively followed, and event-free survival (EFS) was defined as time from diagnosis to progression, re-treatment, or death due to any cause. Landmark EFS timepoints were assessed at 12 (EFS12) and 24 (EFS24) months after the date of diagnosis. Subsequent OS was defined as time from a specific endpoint (diagnosis, event or EFS landmark). Replication was performed in a population-based cohort of T-cell lymphomas diagnosed from 2000-2009 from the Swedish Lymphoma Registry. Results. 138 eligible patients were enrolled in the MER from 2002-2012, the median age at diagnosis was 58 years (range, 19-88), 66% were male, 73% had Stage III-IV disease, and 33% had IPI 0-1. At a median follow-up of 47 months (range 11-120), 87 patients (63%) had an event and 70 patients (51%) had died. From diagnosis, only 60 patients were event-free at 12 months (EFS12 45%). Patients who failed to achieve EFS12 had a poor subsequent OS from event (median OS = 6.8 months, 95% CI: 5.3-14.0, figure 1). In contrast, patients who achieved EFS12 had a favorable subsequent OS (median unreached, figure 2). Of the 427 eligible patients in the Swedish registry, the median age at diagnosis was 66 years (range, 18-88), 63% were male, 68% had Stage III-IV disease, and 25% had IPI 0-1. PTCL subtypes were: ALK-negative ALCL (N=89); AITL (N=80); PTCL, NOS (N=183); EATL (N=44); ENKTL (N=24); and HSTCL (N=7). At a median follow-up of 86 months (range 40-158), 333 patients (79%) had an event and 316 patients (74%) had died. From diagnosis, 183 patients were event-free at 12 months (EFS12 44%). Similar to the MER cohort, Swedish patients failing EFS12 had poor subsequent survival (median OS = 3.7 months, 95% CI: 2.9-5.3, figure 1). Swedish patients achieving EFS12 had a favorable subsequent OS (median OS = 89 months, figure 2). Similar results were obtained when conducting landmark analysis at 24 months after diagnosis (EFS24). Conclusion. Relapse and re-treatment events within the first 12 months of diagnosis are associated with very poor OS in PTCL treated with anthracyclines or related chemotherapy, while patients achieving EFS12 have encouraging subsequent OS. Stratifying patients into prognostically distinct subsets using EFS12 may help focus biologic and biomarker studies. EFS12 has potential as an early endpoint for studies of newly diagnosed PTCL. Further investigation of determinants related to post-EFS12 survival is needed. Disclosures Maurer: Kite Pharma: Research Funding. Cerhan:Kite Pharma: Research Funding. Ansell:Bristol-Myers Squibb: Research Funding; Celldex: Research Funding. Link:Genentech: Consultancy, Research Funding; Kite Pharma: Research Funding. Thompson:Kite Pharma: Research Funding. Relander:Respiratorius: Patents & Royalties: valproate for DLBCL.

Abstract Background: Peripheral T-cell lymphomas (PTCLs) comprise a group of non-Hodgkin lymphomas (NHLs) of mature T-cell origin with generally aggressive clinical behavior. Most systemic PTCLs are treated with anthracycline-based combination chemotherapy; however, outcomes remain relatively poor for most subtypes except ALK-positive anaplastic large cell lymphoma (ALCL). We have used landmark analyses based on event-free survival (EFS) to identify clinically useful endpoints in B-cell NHLs, with EFS at 24 (EFS24) months identified to stratify overall survival (OS) in aggressive B-cell NHL. Here we examined the ability of EFS24 to predict subsequent OS in a large, multinational PTCL cohort. Methods: A cohort of newly diagnosed PTCL patients treated with curative intent combination chemotherapy regimens was assembled from the University of Iowa/Mayo Clinic SPORE Molecular Epidemiology Resource (MER), Swedish Lymphoma Registry (SWE), and British Columbia Cancer Agency (BCCA). Subtypes included ALK-negative ALCL, angioimmunoblastic T-cell lymphoma (AITL), PTCL, not otherwise specified (NOS), enteropathy-associated T-cell lymphoma (EATL), extranodal NK/T-cell lymphoma, nasal type (ENKTL), and hepatosplenic T-cell lymphoma (HSTCL). Patients were followed based on local institution guidelines, and EFS was defined as time from the date of pathologic diagnosis to progression, re-treatment, or death due to any cause. EFS24 was defined as being alive and event-free 24 months from diagnosis. Subsequent OS was defined as time from achieving EFS24 (24 months from diagnosis) or time from progression in patients failing to achieve EFS24 (progression within 24 months of diagnosis). OS was compared to the age-, sex-, and country-matched general population using United States, Sweden, and British Columbia rate tables via standardized mortality ratios (SMR) and expected survival. Results: 775 patients diagnosed from 2000-2012 were included in the combined analysis with diagnosis by the WHO classification at the respective institutions (MER=138, SWE=422, BCCA=215). Median age at diagnosis was 64 years (range 18-89) and 63% were male. Patient characteristics are summarized in the table. 736 (95%) received anthracyline-based therapy at diagnosis. At a median follow-up of 77 months (range 1-185), 516 patients (67%) had died. The percentage of patients achieving EFS24 was similar across the 3 cohorts (MER=39%, SWE=35%, BCCA= 36%, combined=36%). Median survival after progression within the first 24 months was only 4.9 months (95% CI: 3.8-5.9), with a 5-year OS of 11% and SMR of 46.4 (95% CI: 41.8-51.3). In contrast, median survival after achieving EFS24 was not reached, with a 5-year OS of 78% (95% CI: 73%-84%). This was inferior to the expected survival of 92% in the age-, sex-, and country matched population (SMR=3.16; 95% CI: 2.48-3.98). In EFS24 subgroup analyses, more favorable outcomes were observed in younger patients (age <=60 years, N=137, 5-year survival of 91% vs. 98% expected) and in patients receiving autologous stem cell transplant in first remission (N=72, 5-year survival of 88% vs. 96% expected). Patients achieving EFS24 who were not transplanted in first remission (N=189) had a 5-year survival of 74% vs. 90% expected. Conclusions: Assessment of EFS24 stratifies subsequent outcome in PTCL. Patients with early relapse from PTCL have extremely poor outcomes. However, over one-third of patients with PTCL remain in remission two years from diagnosis after initial chemotherapy and have encouraging OS rates, although survival remains significantly worse than the matched general population. Subset analysis suggests that younger patients and patients who receive autologous stem-cell transplant in first CR have 5-year survival rates that approach 90%, though still below the expected survival of the background population. The marked differences in OS after failing or achieving EFS24 in PTCL patients suggest that this endpoint may be useful for patient counseling, as a clinical trial endpoint, and as an endpoint to assess novel biomarkers for risk stratification. Table Table. Figure 1. Figure 1. Figure 2. Figure 2. Disclosures Maurer: Celgene: Research Funding; Kite Pharma: Research Funding. Jerkeman:Mundipharma: Research Funding; Amgen: Research Funding; Janssen: Research Funding; Gilead: Research Funding; Celgene: Research Funding. Connors:Seattle Genetics: Research Funding; Millennium Takeda: Research Funding; NanoString Technologies: Research Funding; F Hoffmann-La Roche: Research Funding; Bristol Myers Squib: Research Funding. Ansell:BMS, Seattle Genetics, Merck, Celldex and Affimed: Research Funding.

Abstract Multiple myeloma (MM) is a malignancy of plasma B-cells that is invariably preceded by monoclonal gammopathy of undetermined significance (MGUS), a pre-neoplastic plasma cell proliferative disorder. C57Bl/KaLwRij (KaLwRij) is a spontaneous inbred mouse strain predisposed to benign idiopathic paraproteinemia (BIP), a plasma cell dyscrasia that parallels many features of human pathology including progression to myeloma. In both humans and mice, the genetic basis for MGUS/MM risk is unknown. We sought to identify the genetic basis for MGUS/MM risk in KaLwRij mice to shed light on genes or pathways that mediate disease risk in humans. Using an integrative approach, we combined KaLwRij x B6 haplotype analysis (418 genes) and a MM patient association study (180 genes) to identify five candidate genes likely to contribute to both murine BIP-susceptibility and human MM risk. Surprisingly, we found KaLwRij mice had homozygous germline deletion of one of the five candidate genes, Samsn1, a putative negative regulator of B-cell activation. Consistent with the reported inhibitory function of SAMSN1 in B-cells, KaLwRij mice had enhanced naïve B-cell response in vitro following stimulation with IL4 and LPS and in vivo following immunization. We found that re-expression of Samsn1 in KaLwRij-derived myeloma cell line 5TGM1 decreased MM tumor growth in vitro, suggesting that loss of Samsn1 contributes to tumor growth in part through a cell intrinsic mechanism. Importantly, germline risk alleles may also influence cell types beyond the pre-malignant B-cells. It is established that the host environment also plays a critical role in supporting myeloma growth in KaLwRij mice. We found that Samsn1 is highly expressed in macrophages, but not in other MM-supportive cell types including osteoclasts and bone marrow stromal cells. Myeloma-associated macrophages play critical roles in supporting tumor growth and are broadly classified as anti-tumor M1 macrophages and tumor-promoting M2 macrophages. Microarray analysis of macrophages from B6 and KaLwRij mice prior to onset of BIP revealed three differentially expressed genes, but only one, Samsn1, is conserved in the human genome. We found that both unpolararized primary peritoneal and MCSF cultured bone marrow macrophages from healthy KaLwRij mice had markedly elevated expression of pro-tumorigenic M2 macrophage markers FIZZ1 and YM1 compared to B6 controls, despite the absence of activating cytokines. To confirm that loss of Samsn1 influenced macrophage activation and M2 polarization, we obtained bone marrow macrophages from mice with a targeted deletion of Samsn1 and found that unpolarized Samsn1-/- cells had similarly increased pro-tumor M2 macrophage marker expression. To evaluate the biologic significance of Samsn1 loss in macrophages on MM tumor growth, we established 5TGM1 MM tumors and injected M2 polarized macrophages from B6, KaLwRij, or Samsn1-/- mice. We found that MM tumor burden was markedly enhanced by the addition of a Samsn1-/- or KaLwRij macrophages compared to wild type macrophages. Thus, we found that loss of Samsn1 in macrophages enhances M2 polarization, prior to MGUS/MM development and can promote established myeloma tumor growth. Together, this data suggests that Samsn1 is a gene contributing to BIP-susceptibility in KaLwRij mice through mutually exclusive functions in multiple cell types including B-cells and macrophages. It is likely that SAMSN1 and its pathway members contribute to human MM progression, and may represent a point for preventative therapeutic intervention. Disclosures No relevant conflicts of interest to declare.

INTRODUCTION: It is becoming clear that eosinophilic esophagitis (EoE) activity cannot be measured by eosinophils alone, and that a more complete assessment is needed. The EoE Histology Scoring System (EoE HSS) measures the severity (grade) and extent (stage) of 8 histopathologic features in EoE: eosinophilic inflammation (EI); basal zone hyperplasia (BZH); eosinophilic abscess (EA); eosinophilic surface layering (SL); dilated intercellular spaces (DIS); surface epithelial alteration (SEA); dyskeratotic epithelial cells (DEC); and lamina propria fibrosis (LPF). We aimed to assess EoE histology at baseline using the EoE HSS, and to compare correlations between this and endoscopic and symptom outcomes. METHODS: This study analyzed baseline data from a 12-week, phase 2, randomized, placebo-controlled trial of budesonide oral suspension in patients with EoE (MPI 101-06; NCT01642212). Patients were eligible for inclusion if they were aged 11–40 years and had EoE with dysphagia. Esophageal biopsies from patients were examined, and mean EoE HSS total score ratios and mean individual feature scores were calculated at baseline for all patients (irrespective of treatment allocation). A correlation analysis was then performed to compare these scores with Dysphagia Symptom Questionnaire (DSQ) scores and those from the EoE Endoscopic Reference Score (EREFS) system at baseline. RESULTS: In total, 87 patients were included for analysis. At baseline, mean (standard deviation) EoE HSS grade and stage total score ratios for all patients were 0.5 (0.2) and 0.4 (0.1), respectively. For individual EoE HSS features, a summary of mean grade and stage scores at baseline is shown in Table 1; the most severe features for grade and stage were EI, BZH, DIS and LPF. At baseline, mean EoE HSS grade and stage total score ratios did not correlate with mean DSQ score, but did correlate significantly with mean EREFS score (grade: R = 0.3166; P = 0.0028; stage: R = 0.3344; P = 0.0015; Table 2). Similarly, mean scores for individual EoE HSS features did not correlate with mean DSQ score at baseline, but did correlate with mean EREFS score for 4 and 3 of the 8 features for grade and stage scores, respectively (Table 2). CONCLUSION: The most severe EoE HSS features at baseline for grade and stage were EI, BZH, DIS and LPF. At baseline, there were significant correlations between the EoE HSS and endoscopic severity, but not dysphagia. This suggests that the EoE HSS could become an essential and independent tool to measure EoE activity.

INTRODUCTION: Eosinophilic esophagitis (EoE) is a chronic immune-mediated disease for which there is an unmet clinical need for new therapies. The safety and efficacy of budesonide oral suspension (BOS) for the treatment of EoE has been demonstrated in a previous phase 2 study. The current phase 3 study evaluated the efficacy and safety of BOS in a large cohort of patients with EoE. METHODS: This randomized, double-blind, placebo-controlled trial (SHP621-301; NCT02605837) investigated the safety and efficacy of BOS in patients (11–55 years) with EoE and dysphagia. Patients were randomized 2:1 to 2.0 mg BOS or placebo twice daily (b.i.d.) for 12 weeks (Figure 1). Co-primary endpoints were histologic (peak eosinophil count ≤6 eosinophils/high-powered field [eos/hpf]) and dysphagia symptom (≥30% decrease in symptoms as measured by the Dysphagia Symptom Questionnaire [DSQ]) responses after 12 weeks of therapy. Secondary endpoints included change in DSQ score and change in EoE Endoscopic Reference Score (EREFS) from baseline to final treatment period. Safety was also assessed. RESULTS: A total of 322 patients were randomized (BOS, n = 215; placebo, n = 107), of whom 318 patients received at least one dose of double-blind therapy (BOS, n = 213; placebo, n = 105) (Table 1). The primary outcomes were achieved, with significantly more histologic and symptom responders in the BOS-treated than the placebo-treated group (53.1% vs 1.0%, P < 0.001; 52.6% vs 39.1%, P = 0.024, respectively; Figure 2). Improvements in mean DSQ score from baseline to week 12 were significantly greater in the BOS group (n = 197) than the placebo group (n = 89) (−13.0 vs −9.1; P = 0.015). Similarly, improvements in mean EREFS scores were significantly greater with BOS (n = 202) than placebo (n = 93) (−4.0 vs −2.2; P < 0.001). In total, 61.0% of patients reported a treatment-emergent adverse event (TEAE) (BOS, 61.0%; placebo, 61.0%). Only 2.5% of patients experienced a TEAE leading to dose discontinuation (BOS, 1.4%; placebo, 4.8%). Few patients had severe or serious TEAEs on BOS or placebo. No life-threatening TEAEs were reported. CONCLUSION: This phase 3 trial demonstrated the efficacy of BOS as induction therapy for EoE. BOS resulted in significant improvements in histologic, symptomatic and endoscopic endpoints compared with placebo. The majority of TEAEs were mild to moderate and comparable between placebo and BOS. A double-blind, placebo-controlled maintenance study (SHP621-302) is ongoing.

Abstract We previously identified five single nucleotide polymorphisms (SNPs) at four susceptibility loci for diffuse large B-cell lymphoma (DLBCL) in individuals of European ancestry through a large genome-wide association study (GWAS). To further elucidate genetic susceptibility to DLBCL, we sought to validate two loci at 3q13.33 and 3p24.1 that were suggestive in the original GWAS with additional genotyping. In the meta-analysis (5662 cases and 9237 controls) of the four original GWAS discovery scans and three replication studies, the 3q13.33 locus (rs9831894; minor allele frequency [MAF] = 0.40) was associated with DLBCL risk [odds ratio (OR) = 0.83, P = 3.62 × 10−13]. rs9831894 is in linkage disequilibrium (LD) with additional variants that are part of a super-enhancer that physically interacts with promoters of CD86 and ILDR1. In the meta-analysis (5510 cases and 12 817 controls) of the four GWAS discovery scans and four replication studies, the 3p24.1 locus (rs6773363; MAF = 0.45) was also associated with DLBCL risk (OR = 1.20, P = 2.31 × 10−12). This SNP is 29 426-bp upstream of the nearest gene EOMES and in LD with additional SNPs that are part of a highly lineage-specific and tumor-acquired super-enhancer that shows long-range interaction with AZI2 promoter. These loci provide additional evidence for the role of immune function in the etiology of DLBCL, the most common lymphoma subtype.