Syrbu, Sergei

Abstract Abstract 1604 Background EBV (+) DLBCL of the elderly is a lymphoproliferative disorder recently included as a provisional entity in the 2008 WHO classification of lymphoid tumors. Defined as EBV (+) DLBCL in patients over the age of 50 years without known immunosuppression, information is evolving in this entity. To date, the true incidence of EBV (+) DLBCL in adults remains imprecisely determined and may vary regionally. This study sought to determine the incidence, presenting clinical characteristics, and outcome of EBV (+) in an unselected cohort of DLBCL patients enrolled in a prospective observational study. Methods The University of Iowa/Mayo Clinic SPORE Molecular Epidemiology Resource (MER) is a prospective, longitudinal observational study designed to collect information on patterns of care and outcomes for patients with newly diagnosed lymphoma. Patients seen at the Mayo Clinic, Rochester MN and the University of Iowa within 9 months of their initial diagnosis of lymphoma are offered enrollment. HIV (+) patients are excluded. Baseline patient reported data, clinical data and initial management are collected using a standard protocol and a central pathology review is performed. After enrollment, patients are actively followed for events (disease progression, retreatment, and death) and disease related comorbidities. Tissue Micro Arrays (TMA) are constructed on available primary biopsy specimens. Epstein Barr Encoded RNA (EBER) EBV testing was performed by in-situ hybridization, and scored by an expert hematopathologist. EBER reactivity in more than 30% of malignant cells were required for EBV(+) designation. All DLBCL patients from the MER with available TMA excluding primary mediastinal DLBCL and post transplant lymphoproliferative disorders (PTLD) are included in the current analysis. Event free survival (EFS) was defined as time from diagnosis until recurrence, retreatment, or death due to any cause. Results 184 newly diagnosed DLBCL patients with available TMAs were enrolled in the MER from 2002–2009. The median age at enrollment was 62 (range 18–89) and 57% were male. 89.7% were treated with immunochemotherapy. At a median follow-up of 66 months (range 1–116), 80 patients (43%) had an event which included 59(32%) deaths. TMA testing was positive for EBV in 13 (7 %) samples with an even distribution among age groups. There was a trend toward higher percentage of stage III/IV disease (85 vs 57%, p = 0.052), and BM involvement (46 vs 16%). EBV (+) was not associated with other extranodal disease or further identifiable differences in presenting clinical characteristics. Controlling for IPI, the hazard ratio for EFS among EBV+ in DLBCL pts over 50 was 0.41 (95% CI = 0.13–1.32) p = 0.14. EFS and OS curves for pts over 50 are shown below. There were no events or deaths in the 4 EBV+ pts under age 50. Conclusions EBV+ DLBCL represents a small proportion of DLBCL patients presenting for care to our academic medical centers, consistent with reports from other regions. Substantial unique clinical characteristics at presentation for those pts with EBV+ disease were not identified, and outcomes were no worse than EBV (−) counterparts. Given the apparent regional differences in reports of EBV(+) DLBCL of the elderly, future clinical series will need to establish a more precise definition or determine more distinctive features to justify adoption of EBV(+) DLBCL of the elderly as a full entity in the WHO classification. Disclosures: No relevant conflicts of interest to declare.

Abstract Abstract 1546 Background: Follicular lymphoma (FL) is an incurable disease with an undefined optimal management strategy. Global priorities in goals of care are avoidance of death and transformation to aggressive subtypes. Retrospective series, – most including patients diagnosed before ubiquitous rituximab use, - describe diverse rates of transformation with a common consensus of 3% per year, and with a median survival post transformation of less than 2 years. This study sought to characterize transformation events in a prospective observational series begun after diffusion of early rituximab use in FL. Methods: Newly diagnosed FL patients were prospectively enrolled in the University of Iowa/Mayo Clinic SPORE Molecular Epidemiology Resource (MER) from 2002–2009. Clinical data were abstracted from medical records using a standard protocol. Patients were actively followed for retreatment, transformation, and death. Inclusion criteria for this analysis were initial diagnosis of grade I-IIIa FL. Exclusion criteria for this cohort include composite diffuse large B-cell lymphoma (DLBCL), FL grade IIIb, or evidence of clinical or pathological transformation at the time of FL diagnosis. Transformation was defined as refractory/recurrent disease with either a) biopsy confirmed subtype of FLIIIb, DLBCL or higher grade B-cell lymphoma; or b) clinical indication of transformation (sudden rise in LDH, rapid discordant localized nodal growth, new involvement of unusual extranodal sites, new B symptoms or hypercalcemia). Risk of transformation was analyzed via time to transformation using a death as a competing risk. Time to transformation was defined as the date of initial FL diagnosis to date of transformation. Overall survival was defined as the date of initial diagnosis to date of death or last known follow-up for patients still alive. Results: There were 631 newly diagnosed grade I-IIIa FL patients with a median age at enrollment of 60 years (range 23–93). 54% were male. The most common types of initial therapy were observation (33%), rituximab (R) monotherapy (12%), alkylator based chemotherapy +/− R (22%), and anthracycline based chemotherapy +/− R (20%). At a median follow-up of 60 months (range 11–110), 79 patients had died, 311 patients had an event (death, progression, or retreatment), and 60 patients (9.5%) had transformed. Transformation was biopsy proven in 48 of the 60 patients (80%). The overall transformation rate at 5 years (TX5) was 10.7% (95% CI: 8.3%–13.8%) (Figure 1). Time to transformation was associated with a FLIPI score of 3–5 (HR=2.37, 95% CI 1.28–4.39, p=0.006), but was not significantly associated with other standard clinical characteristics. Risk of transformation was different in the common initial treatment groups with the highest rate in patients who were initially observed (TX5=14.4%) and lowest rate in patients who initially received R monotherapy (TX5=3.2%)(p=0.058). Outcome after transformation was inferior to MER subjects with de-novo diagnosed DLBCL (p<0.0001). The median overall survival from date of transformation was 44 months (95% CI: 22-NA). Survival after transformation was superior in patients who transformed greater than 18 months after FL diagnosis compared to patients who transformed earlier (5 yr OS =70% vs 20%) (p=7 ×10−5), and for those initially observed (median unreached) versus those patients who were initially treated with alkylator or anthracycline based chemotherapy (median survival of 11 months)( p=0.016). Conclusions: Follicular transformation rates in this modern large prospective observational study are similar to risk of death without transformation and slightly lower at 5 years than most previous reports. Post-transformation prognosis is substantially better than described in older series. These observed differences may be a function of the prospective nature of the study design, modern management strategies, or patient selection factors. Initial management strategies may influence the risk of transformation. Marked survival differences following early vs. late transformation suggest that these may be different biologic events. Disclosures: Link: Genentech: Consultancy, Research Funding; Celgene: Consultancy; Millenium: Consultancy. Johnston:Novartis: Consultancy.

Abstract Abstract 1563 Intro: Optimal treatment for non-follicular low grade B-cell lymphoma (NFLGL) is not well defined. Clinical trial design for these subtypes would be enhanced by further understanding of early presentation and management. A large prospective observational study was used to identify presenting clinical features, describe patterns of care and compare the prognostic utility of International Prognostic Index (IPI) and the Follicular Lymphoma International Prognostic Index (FLIPI). Methods: The University of Iowa/Mayo Clinic SPORE Molecular Epidemiology Resource (MER) is a prospective, longitudinal observational study designed to collect information on patterns of care and outcomes for patients with newly diagnosed lymphoma. Patients seen at the Mayo Clinic, Rochester MN and the University of Iowa within 9 months of their initial diagnosis of lymphoma are offered enrollment. Baseline patient reported data, clinical data and initial management are collected using a standard protocol and a central pathology review is performed. After enrollment, patients are actively followed for events (disease progression, retreatment, and death) and disease related comorbidities. This analysis includes 198 patients diagnosed with extranodal marginal zone (EMZL), 22 with nodal marginal zone (NMZL), 47 with splenic marginal zone (SMZL), 48 with lymphoplasmacytic lymphoma (LPL), as well as 67 patients with unclassifiable low-grade B-cell lymphoma (B-NOS). Results: 382 newly diagnosed NFLGBL patients were enrolled in the MER from 2002–2009. The median age at enrollment was 63 years (range 22–95). 52% were male. The most common types of initial therapy after diagnosis were observation (41 %), alkylator- based chemotherapy +/− rituximab (R) (17%), radiation therapy alone (15%) and R monotherapy (13%). At median follow-up of 60 months (range 1–121), 51 patients were deceased and 155 had an event. The clinical characteristics that comprise the IPI and FLIPI were similar across the subtypes. Approximately half of the cases presented at low risk (55% IPI; 48% FLIPI). A majority had a normal LDH (81%), limited nodal involvement (91% had ≤ 4 groups), normal hemoglobin (71% ≥12 g/dL), good performance status (95% 0–1), and advanced stage (57% stages III-IV). There were notable differences among the NFLGBL subtypes. Patients with SMZL and LPL presented with high risk FLIPI of 3–5 (49% and 46% respectively) and high to high-intermediate IPI of 3–5 (21% and 13%). Abnormal LDH and anemia (< 12 g/dL) were more frequent in patients with SMZL (40%; 56%) and LPL (25%; 62%). EMZL presented with lower stages (70% stage I-II) and NMZL presented with increased nodal involvement (38% >4 sites). SMZL had the highest rates of surgical resection (21%) and EMZL was more frequently treated with radiation therapy (25%). LPL (30%) and NMZL (32%) more commonly received alkylator based chemotherapy +/− R. While both IPI and FLIPI differentiated outcome in these patients, FLIPI had higher c-statistics than IPI for both EFS (0.583 vs 0.568) and OS (0.685 vs 0.661), respectively. Conclusions: This large prospective collection of data on NFLGBL patients presenting to academic medical centers provides a modern picture of presentation and management patterns useful to investigators designing clinical trials. FLIPI may have more prognostic utility than IPI in this group of patients. Disclosures: Ansell: Seattle Genetics, Inc.: Research Funding.

Abstract BACKGROUND: Diffuse large B-cell lymphoma, not otherwise specified (DLBCL), though defined as one disease entity, consists of two main cell-of-origin (COO) subtypes, germinal center B-cell like (GCB) and activated B-cell like (ABC), with the latter predicting a significantly worse prognosis using conventional chemotherapy. Up to 40% of all patients diagnosed with DLBCL will experience relapse, and outcomes are generally poor in this setting. In this study, we examine the proportion of GCB vs. non-GCB subtypes at initial diagnosis and at time of relapse, and assess the incidence of reclassification from one subtype to another. 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. All relapse events were validated by review of the medical record. This analysis includes patients diagnosed with DLBCL who underwent initial treatment and subsequently experienced relapse as confirmed by biopsy. Immunohistochemical staining data including CD10, Bcl-6, and Mum-1, were collected from available pathology reports and classified to either GCB or non-GCB subtypes as predicted by the Hans algorithm. We compared subtype classification and individual immunohistochemical data both at the time of diagnosis and relapse. The overall subtype agreement between the two diagnostic time points was assessed. RESULTS: 1023 patients with newly diagnosed DLBCL were enrolled in the MER from 2002 - 2012. Of those, 249 had documented disease relapse. Of those analyzed, a total of 43 patients had COO classification based on the Hans algorithm from tissue biopsy at both diagnosis and relapse. Thirty patients were characterized as GCB DLBCL on initial presentation, and upon relapse 28 were noted to be GCB, while 2 were noted to be the non-GCB subtype. Of the 13 that were characterized as non-GCB on initial presentation, 10 remained non-GCB while 3 were reclassified as GCB. The overall agreement of DLBCL COO phenotypes between initial diagnosis and relapse was 88%. Seven percent of those initially diagnosed as GCB were reclassified as non-GCB subtype; in contrast, 23% of those initially diagnosed as non-GCB had changed to GCB upon relapse. Similar analysis was performed on individual immunohistochemical staining factors including CD10, Bcl-6, and Mum-1, and we observed overall agreement of 88%, 87%, and 91%, respectively. CONCLUSIONS: A majority of patients with relapsed DLBCL exhibit similar COO phenotypes at initial presentation and at relapse, and the incidence of reclassification from one subtype to another is uncommon. This suggests that the initial treatment regimen for DLBCL rarely alters the basic cancer phenotype when immunohistochemistry laboratory technical factors and pathologist interpretive discrepancies are excluded as causes for this change. However, reclassification from GCB to non-GCB subtypes is observed in a minority of cases, which may affect the overall outcome and response to treatment. Further studies are needed using gene expression to categorize COO and to examine the factors surrounding the time of relapse for possible harbingers of relapse as well as the behavior and outcome of reclassified DLBCL. Table Table. Disclosures Ansell: BMS, Seattle Genetics, Merck, Celldex and Affimed: Research Funding.

Abstract Background. Diffuse large B-cell lymphoma (DLBCL) is curable for the majority of patients treated with anthracycline based immunochemotherapy (IC). While most patients achieve response to initial therapy, a subset of patients are refractory to initial IC or become refractory to subsequent salvage therapies. Prognosis in this setting is very poor. Here we determine the incidence of refractory disease from a large cohort of DLBCL prospectively followed from diagnosis in the IC era and assess outcomes in these patients. Methods. Patients were prospectively enrolled in the University of Iowa/Mayo Clinic Lymphoma SPORE Molecular Epidemiology Resource (MER) within 9 months of diagnosis. Patients were followed for relapse, retreatment, and death; all events were validated by medical record. This analysis includes patients with DLBCL or primary mediastinal B-cell lymphoma (PMBCL) who received initial treatment of anthracycline based immunochemotherapy; patients with primary CNS lymphoma or post-transplant lymphoproliferative disorders were excluded. Response to therapy was retrospectively classified per 2007 Revised Response Criteria for Malignant Lymphoma from available clinical and radiology records. Refractory disease was defined as having a best response to any systemic therapy of stable disease (SD), progressive disease (PD), or relapse within 12 months of autologous stem cell transplantation (SCT). We also examined patients with transient response to IC as defined by achieving an interim response (CR or PR) but having progressive disease at or prior to the end of the planned number of cycles of IC. Results. 1039 patients with DLBCL or PMBCL lymphoma were enrolled in the MER from 2002-2012 and treated with R-CHOP or comparable IC. Median age at diagnosis was 62 years (range 18-91) and 577 (56%) were male. At a median FU of 60 months (range 1-148), 136 patients developed refractory disease. The median age at diagnosis of patients with refractory disease was 62 years (range 19-87). The cumulative incidence of refractory DLBCL was 11.3% at 2 years (95%: CI: 9.5-13.4) and 13.1% at 5 years (95% CI: 11.2-15.4). The median overall survival after becoming refractory was 4.7 months (95% CI: 4.1-5.5) with a 1 year survival rate of 21% (95% CI: 15%-30%). The median number of therapies before becoming refractory was 2 with 35 patients becoming refractory following their first therapy (i.e. IC), 83 patients becoming refractory after their 2nd therapy, and 23 patients becoming refractory after their 3rd or later therapy; 27 patients had received stem cell transplant prior to becoming refractory. Outcomes were poor regardless of when patients became refractory (figure). Patients received a median (range) of 2 (0-8) treatments after becoming refractory with 40% (N=54) attempting subsequent platinum based salvage therapy and 14% (N=9) proceeding to ASCT, of which only 6 remain alive in long-term remission. 41 patients (30%) were treated on clinical trials after becoming refractory. Response rate for the first therapy after becoming refractory was 21%, while 29% of patients had a response to any subsequent therapy. Once patients became refractory, there was no difference in survival based on response at end of initial IC (p=0.33), cell of origin at diagnosis (p=0.64), IPI at diagnosis (p=0.33), or age when refractory (p=0.66). Outcomes in patients with transient response to IC (n=58) were poor, with the majority (N=37, 63%) becoming refractory to subsequent therapy. Median OS after first relapse was 6.7 months in patients with transient response to IC, which was equivalent to patients refractory to IC (p=0.99). The majority of patients with transient response to IC (69%) were next treated with platinum based salvage therapy which had a response rate of 40%. Ultimately 15 of the 58 patients (26%) proceeded to transplant, of which only 5 (9%) achieved long-term remission. Conclusions. Approximately 13% of patients with DLBCL become refractory to treatment in their disease course. Outcomes once patients become refractory are extremely poor regardless of when patients become refractory. Standard prognostic factors are no longer predictive of outcome and stem cell transplant had limited benefit in this group of patients. Patients with transient response to initial immunochemotherapy should be included when classifying patients as refractory. New therapy strategies are needed in the refractory setting. Figure 1. Figure 1. Disclosures Maurer: Kite Pharma: Research Funding. Thompson:Kite Pharma: Research Funding. Farooq: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.

Abstract Background: Follicular lymphoma (FL) is an indolent lymphoma generally considered incurable with current standard therapies. Recent advances have resulted in prolongation of overall survival (OS) for patients with FL such that death from competing causes may now limit the mortality impact of FL in some patient groups. Identification of patients for whom FL related mortality is expected to be minimal, or conversely those at high risk of disease related mortality, is highly clinically relevant. We recently reported (Maurer et al, JCO 2014;32:1066-73) that event-free survival (EFS) at 24 months from diagnosis is a robust endpoint for disease related outcome in patients with diffuse large B cell lymphoma (DLBCL). Here we use the same approach to assess if landmark timepoints of EFS can stratify subsequent OS in FL. Methods: All newly diagnosed grade 1-3a FL patients enrolled on the University of Iowa/Mayo Clinic Lymphoma SPORE Molecular Epidemiology Resource (MER) from 2002-2011 were eligible. Patients with grade 3b FL, transformation, or presence of DLBCL at diagnosis were excluded. EFS was defined as time from diagnosis to progression, relapse, re-treatment, or death due to any cause. EFS12 was defined based on EFS status 12 months after date of diagnosis; we also assessed EFS at 24 months. OS was defined as time from a specific timepoint (diagnosis, event, or EFS12) until death due to any cause. OS was compared to age and sex matched survival in the general US population using an expected survival approach and standardized mortality ratios (SMR) and 95% confidence intervals (CI). Outcomes were examined in all patients as well as selected subsets defined by initial treatment. Replication was performed using a Lyon, France hospital registry of newly diagnosed grade 1-3a FL patients enrolled from 2002-2010 with survival compared to French population data. Results: 936 patients with grade 1-3a FL were eligible from the MER. The median age at diagnosis was 60 years (range 19-91) and 53% were male. 86% had grade 1-2 disease and 14% grade 3a disease. 23% had high-risk disease (FLIPI score ≥3). 347 (37%) were initially treated with alkylator or anthracyline based immunochemotherapy (IC), 113 (12%) rituximab monotherapy (RM), and 318 (34%) were initially observed; the remaining patients received radiation for limited stage disease (8%), chemotherapy without rituximab (4%), or other therapy (5%). At a median follow-up of 59 months (range 1-131), 403 patients (43%) had an event and 120 patients (13%) had died; 155 patients (17%) failed to achieve EFS12. From diagnosis, patients with FL had inferior OS compared to the general population (SMR=1.24, 95% CI: 1.03-1.48, p=0.018); results were similar for patients with grade 1-2 (SMR=1.23) and grade 3a (SMR=1.29) disease. The survival deficit was eliminated in patients who achieved EFS12 (SMR=0.85, 95% CI: 0.66-1.09, p=0.20, Fig 1a), and so we did not pursue modeling EFS24. In contrast, patients with a non-death event (relapse, retreatment, or progression) within 12 months of diagnosis had inferior subsequent OS (SMR=3.90, 95% CI: 2.89-5.25, p=4.8x10-19, Fig 1b). These results were replicated in 153 FL patients from the Lyon registry: patients who achieved EFS12 had equivalent subsequent OS to the general French population (SMR=0.82, 95% CI: 0.39-1.72, p=0.60, Fig 1c), while patients who failed to achieve EFS12 had poor subsequent OS (SMR=4.16, 95% CI: 1.34-12.91, p=0.013, Fig 1d). In subset analysis of the MER, patients achieving EFS12 initially treated with IC (SMR=0.98, 95% CI: 0.63-1.54, p=0.93), RM (SMR=0.66, 95% CI: 0.31-1.38, p=0.27), or observation (SMR=0.73, 95% CI: 0.47-1.15, p=0.18) had equivalent OS to the population. In contrast, for patients not achieving EFS12, OS after event was inferior for those treated with IC (SMR=15.0, 95% CI: 10.22-22.05, p=2.0x10-43) or RM (SMR=4.96, 95% CI: 1.24-19.84, p=0.023), while trending towards inferior for those initially observed (SMR=1.55, 95% CI: 0.81-2.99, p=0.19). Summary: Events within the first 12 months of diagnosis are associated with poor OS in FL, especially in patients treated with IC, while patients achieving EFS12 have excellent subsequent survival, overall and in the main treatment subsets. Prognosis for FL patients should be recalibrated at 12 months from diagnosis. EFS12 will be useful in counseling and should be considered as an endpoint in studies of newly diagnosed FL. Figure 1 Figure 1. Disclosures No relevant conflicts of interest to declare.

AbstractAnaplastic large cell lymphomas (ALCLs) represent a relatively common group of T-cell non-Hodgkin lymphomas (T-NHLs) that are unified by similar pathologic features but demonstrate marked genetic heterogeneity. ALCLs are broadly classified as being anaplastic lymphoma kinase (ALK)+ or ALK−, based on the presence or absence of ALK rearrangements. Exome sequencing of 62 T-NHLs identified a previously unreported recurrent mutation in the musculin gene, MSCE116K, exclusively in ALK− ALCLs. Additional sequencing for a total of 238 T-NHLs confirmed the specificity of MSCE116K for ALK− ALCL and further demonstrated that 14 of 15 mutated cases (93%) had coexisting DUSP22 rearrangements. Musculin is a basic helix-loop-helix (bHLH) transcription factor that heterodimerizes with other bHLH proteins to regulate lymphocyte development. The E116K mutation localized to the DNA binding domain of musculin and permitted formation of musculin–bHLH heterodimers but prevented their binding to authentic target sequence. Functional analysis showed MSCE116K acted in a dominant-negative fashion, reversing wild-type musculin-induced repression of MYC and cell cycle inhibition. Chromatin immunoprecipitation–sequencing and transcriptome analysis identified the cell cycle regulatory gene E2F2 as a direct transcriptional target of musculin. MSCE116K reversed E2F2-induced cell cycle arrest and promoted expression of the CD30–IRF4–MYC axis, whereas its expression was reciprocally induced by binding of IRF4 to the MSC promoter. Finally, ALCL cells expressing MSCE116K were preferentially targeted by the BET inhibitor JQ1. These findings identify a novel recurrent MSC mutation as a key driver of the CD30–IRF4–MYC axis and cell cycle progression in a unique subset of ALCLs.

AbstractIndolent B‐cell lymphomas other than follicular lymphoma account for up to 10% of all B‐cell neoplasms. While they typically follow a slowly progressive course, some patients experience rapid progression and early mortality. Prognostic scoring systems have not been adopted, hindering the ability of clinicians or researchers to predict outcomes, or risk‐stratify patients during clinical trials. To address this, we evaluated the utility of existing prognostic indices and novel, early disease‐related outcomes, to predict subsequent long term survival. Baseline characteristics and outcomes data were generated from a longitudinal cohort study that prospectively enrolled 632 patients newly diagnosed with marginal zone lymphoma, lymphoplasmacytic lymphomas, or B‐cell lymphomas not otherwise specified, beginning in 2002. The International Prognostic Index (IPI), Follicular Lymphoma International Prognostic Index (FLIPI), and MALT International prognostic index (MALT‐IPI) demonstrated c‐statistics that ranged from 0.593‐0.612 for event‐free survival (EFS), and 0.683‐0.714 for overall survival (OS). Patients who attained event‐free survival at 12 months (EFS12) experienced similar mortality to the US general population (standardized mortality ratio [SMR] 1.19; 95% CI 0.95‐1.46). Patients who did not attain EFS12 had subsequent worse morality (SMR 3.14 (95% CI 2.05‐4.59). The MALT‐IPI demonstrated utility in predicting subsequent long‐term outcomes among patients with non‐follicular indolent B‐cell lymphomas. This index should be used by clinicians giving guidance to patients at the time of initial diagnosis, and risk stratification during clinical studies. The divergent long‐term outcomes experienced by patients who do or do not attain EFS12 suggest there exists a subset of patients who harbor high‐risk disease. Future research efforts should focus on methods to identify these patients at the time of diagnosis, in order to enable risk‐tailored therapy.