Witzig, Thomas E.

Abstract Abstract 1525 Background: Nodular lymphocyte predominant Hodgkin Lymphoma (NLPHL) is a more indolent form of Hodgkin Lymphoma that is usually associated with favorable outcomes. However, a number of reports have shown a tendency of transformation to more aggressive types of lymphoma, typically diffuse large B-cell lymphoma (DLBCL). Long-term data on the incidence and outcomes of transformed NLPHL is lacking in the literature. The aim of this study was to evaluate incidence, risk factors and outcomes of DLBCL transformation in NLPHL in a cohort of patients followed at a single institution. Methods: The actively maintained Mayo Clinic Lymphoma Database includes all consenting consecutive patients with lymphoma seen at Mayo Clinic Rochester. This was used to retrospectively identify patients with NLPHL. The study was approved by the Institutional Review Board. Pathology was reviewed by a hematopathologist and all transformations were histologically confirmed by WHO criteria. The clinical characteristics, therapy and outcomes of patients with NLPHL and DLBCL transformation were analyzed. The chi-square test was used to compare variables. Risk of progression was calculated using a person-year approach. Survival and freedom from transformation were estimated and compared using the Kaplan Meier method and log rank tests, respectively. Results: Between 1970 and 2010, 222 consecutive adult patients with NLPHL were identified. The median follow-up was 20 years. Of these, 17 (7.7%) developed a transformation to DLBCL during the course of the disease (Figure 1). The median time to transformation was 35 (6–248) months. Of these 17 patients, 13 (76.5%) were male, 11 (64.7%) had stage I/II and 6 (35.3%) had stage III/IV NLPHL. Transformation was the first relapse in most patients (12 patients, 70.6%) while five patients (29.4%) developed one or more relapses of NLPHL before transformation. Prior therapies for NLPHL were as follows: radiation therapy in 5 (29.4%), chemotherapy in 5 (29.4%) and combined chemotherapy and radiation in 6 (35.3%) patients. The median age at transformation was 45 years (30–87). Most patients (10 patients, 58.8%) presented with signs (palpable lymph nodes) or “B” symptoms. Eight patients (47.1%) had stage III/IV disease at the time of transformation. The most commonly used regimens for treatment of DLBCL were R-CHOP or CHOP (9 patients, 52.9%). Platinum based therapy was administered in 4 (23.5%) patients. Five patients (29.4%) required more than one line of therapy, and autologous stem cell transplant was utilized in two (11.7%) patients. Based on the observed 17 transformations during 2304 patient-years of follow-up, the rate of transformation was 0.74 per 100 patient-years. The five-year overall survival (OS) of patients with transformed disease (calculated from time of transformation) was 76.4%. The most common cause of death was lymphoma (75%). Following treatment for transformation, 5 patients (29.4%) relapsed. The OS in transformed patients was independent of prior therapies, and transformation did not adversely affect overall survival in our cohort (median survival of in 129 months in transformed versus 120 in non-transformed patients, P=0.33). In a univariate analysis of prior therapies, use of radiation therapy was associated with a significant delay in time to transformation (P= 0.0035) (Table 1, figure 2). Conclusions: The risk of transformation in NLPHL is 0.74% per year in this large single institution case series of NLPHL, and appears to be lower than that observed in follicular and other types of low grade lymphoma. The outcomes of patients with transformation were significantly better than reported in other types of transformed lymphoma and did not adversely affect OS. Disclosures: No relevant conflicts of interest to declare.

Abstract Abstract 1792 High risk disease can be identified in patients with early stage chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL) using biological prognostic markers. We have shown that early therapy of high risk CLL patients with alemtuzumab (ALM) and rituximab (RTX) is effective and could possibly delay first standard treatment (Cancer 2008;113:2110-8). Efficacy of unconjugated monoclonal antibody (mAb) therapy in these patients could be improved by enhancing mAb mediated cellular cytotoxicity. Preclinical studies show that yeast cell wall derived beta glucan, which increases complement receptor 3 (CR3) binding to the complement fragment iC3b on target cells, could increase mAb mediated cellular cytotoxicity. Both ALM and RTX activate complement resulting in deposition of iC3b on the cell membrane. In CLL cells that are not lysed by complement activation, these iC3b molecules are targets for the effector cells mediating cellular cytotoxicity. We hypothesized that PGG beta glucan (Imprime PPG®, Biothera, Eagan MN) an intravenous formulation of a 1,3/1,6 glucose polymer prepared from a strain of Saccharomyces cerevisiae, would improve the efficacy of therapy with ALM and RTX in patients with CLL by increasing CR3 binding to iC3b and thus enhancing macrophage, neutrophil, and NK cell mediated cytotoxicity. We report the results of a Phase I study of the combination of ALM, RTX and PPG beta glucan in patients with CLL. Methods: The primary aim of this IRB approved study (NCT01269385) was to determine the maximum tolerated dose (MTD) of PGG beta glucan that could be safely combined with ALM and RTX. The MTD was defined as the PGG beta glucan dose level below that which induced dose limiting toxicity in at least one third of patients, or the highest dose level tested if all levels were tolerated. Eligibility for the trial required a diagnosis of CLL by standard (IWCLL-NCI 2008) criteria, no prior treatment for CLL, high risk CLL based on molecular markers, absence of standard indications for initiation of therapy for CLL, and adequate performance status and organ function. High risk CLL was defined as at least one of the following: 17p13-; 11q22-; either unmutated (<2%) IGHV or use of VH3–21 as well as CD38+ and/or ZAP70+. Patients received standard premedication for mAb, antimicrobial and allopurinol prophylaxis and weekly PCR testing for CMV reactivation with treatment of viremia. The duration of treatment was 33 days. PGG beta glucan was administered IV on days 1, 5, 10, 17, 24, and 31 and the first dose was premedicated with hydrocortisone 100mg IV, oral acetaminophen 1000 mg and diphenhydramine 50 mg. The starting dose level of PGG beta glucan was 1 mg/kg, 2nd dose level was 2 mg/kg and the 3rd dose level 4 mg/kg. Subcutaneous ALM therapy started on day 3 with daily dose escalation (3 – 10 – 30 mg) and then 30 mg Mon-Wed-Friday for 4 weeks. Weekly RTX started on day 10 at 375 mg/m2 IV × 4 doses. Results: Thirteen patients were enrolled from February 2011 to April 2012. The 11 evaluable patients had a median age of 61 years (range 47 – 77), 73% were male, 3 had early stage disease (Rai 0) and 8 had intermediate stage disease (Rai I n = 7, Rai II n = 1). High-risk parameters were 17p- in 4 patients, 11q22- in 3 patients, and unmutated IGHV and expression of ZAP70 and/or CD38 in 4 patients. There were no dose limiting toxicities. One patient had grade 4 febrile neutropenia, with no grade 3–4 anemias or thrombocytopenias, and there were no grade 3–4 non-hematological toxicities. All patients responded to therapy with 7 CR, 1 CCR, 1 nPR, and 2 PR (IWCLL-NCI 2008 criteria). Median follow up was 6.9 months (2.3 – 13.2) and one patient progressed at 9.7 months. No patients have required treatment for progressive disease and there have been no patient deaths. Two patients were not evaluable: One developed neutropenia and therapy was not held per protocol, and the other developed a grade 2 skin reaction to ALM and treatment was stopped. Discussion: The combination of PGG beta glucan with ALM and RTX is well tolerated at a PGG beta glucan dose of 4 mg/kg. All patients responded to therapy with 64% achieving a CR. These data support continuation of this study in a phase II component. Acknowledgment: This study was funded by the University of Iowa/Mayo Clinic Lymphoma SPORE (CA097274) and Biothera. Disclosures: Zent: Biothera: Research Funding; Genzyme: Research Funding; Genentech: Research Funding; Novartis: Research Funding; GlaxoSmithKline: Research Funding. Off Label Use: Phase I study using PGG beta glucan in CLL.

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: Non-Hodgkin lymphomas (NHL) are increasing in incidence and are now the fifth most common tumor diagnosed each year in the United States. Most NHLs are of B-cell origin but the tumor tissue is variably infiltrated with T-cells. Our group has shown in diffuse B-cell large cell lymphoma, that a high number of intratumoral CD4+ T-cells predicts a better overall survival. It has been shown that recently-characterized CD4+CD25+ regulatory T-cells (Treg cells) played an important role in the mediation of anti-tumor immunity. However, there is no data on the role of intratumoral Treg cells in suppression of autologous infiltrating CD4+ T-cells in B-cell NHL. Goal: To investigate the effect of intratumoral Treg cells on the proliferation of tumor-infiltrating CD4+CD25- T-cells, to determine the underlying mechanism of the T-cell suppression, and evaluate the role that malignant B-cells may play in the recruitment of Treg cells to the site of B-cell NHL. Results: We identified a subset of CD4+CD25+ T-cells over-represented in biopsy specimens of B-cell NHL (these cells comprise 17% of cells in lymphoma biopsies, compared 7% of peripheral blood mononuclear cells, 12% of cells in inflammatory tonsil and 6% of cells in tumor free lymph nodes; p-value =0.001). These CD4+CD25+ T-cells are memory-like T-cells (CD45RO+ and CD45RA−) and express high levels of CTLA-4 and Foxp3 when compared to autologous tumor-infiltrating CD4+CD25- T-cells. Importantly, these CD4+CD25+ T-cells displayed the ability to suppress the proliferation and cytokine (IFN-g and IL-4) production of tumor-infiltrating CD4+CD25- T-cells in response to PHA stimulation. Treatment with anti-B7-H1 antibody or PD-1 fusion protein enhanced the proliferation of infiltrating CD4+CD25- T-cells when co-cultured with intratumoral CD4+CD25+ T-cells. Our results suggest that interaction between B7-H1 and PD-1 accounts for about 30% of intratumoral Treg cell-mediated inhibition of autologous infiltrating CD4+CD25- T-cells in tumor sites of B-cell NHL. Lastly, we found that CCL22 secreted by lymphoma B-cells is involved in the chemotaxis and migration of intratumoral CD4+CD25+ T-cells which express chemokine receptor CCR4, but not CCR8. Conclusion: Our results suggest that tumor microenvironmental CD4+CD25+ regulatory T-cells are important regulators of tumor immunity and that these cells are recruited to the area of lymphoma involvement by the malignant B-cells.

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 Background Follicular lymphoma (FL) is an indolent non-Hodgkin lymphoma (NHL) with heterogeneous outcomes and remains largely incurable. Immunochemotherapy (IC) continues to be the standard therapy backbone in the frontline and relapsed settings, though novel agents are increasingly used and investigated. Lenalidomide is an immunomodulatory molecule with known single-agent activity in relapsed lymphoma. It is also active in the frontline setting and has been reported to be effective and tolerated in upfront combination regimens in FL (Fowler et al, Lancet Oncol. 2014, 15(12):1311-8). Here we report our experience with frontline use of R2CHOP (lenalidomide in combination with R-CHOP) in patients with FL. Methods A phase 1/2 study of R2CHOP was conducted in NHL patients with primarily diffuse large B-cell lymphoma (DLBCL). While the phase 2 study was focused on DLBCL patients, treatment-naive patients with stage II-IV, histologically-confirmed FL (grades 1, 2, and 3a) meeting criteria for therapy were eligible for the phase 1 part of the study. Additionally, FL patients were identified in the phase 2 portion of the study after central pathology review. These patients were allowed to complete therapy and were followed accordingly. Treatment consisted of 6 cycles of R2CHOP with lenalidomide given on days 1-10 and R-CHOP given in 21-day cycles. All patients received pegfilgrastim and aspirin (if not on anticoagulation) along with other supportive measures per provider discretion. Primary objectives were safety assessment and efficacy. Results Ten patients with FL (3 had grade 1, 3 had grade 2, and 4 had grade 3a) were enrolled in the R2CHOP phase 1/2 study at Mayo Clinic. One patient was in the phase 1 arm at dose level 2 (lenalidomide 20 mg/d) and 9 patients were in the phase 2 arm (lenalidomide 25 mg/d). The mean age was 60.8 years (range: 41-82). Eight out of ten patients were male; 5/10 had ECOG performance status of 0; 5/10 had an IPI score of intermediate or higher. All patients completed 6 cycles of planned treatment. One patient required lenalidomide dose adjustment due to toxicity. There were no lenalidomide dose interruptions. The overall response rate (ORR) was 100% and the complete response (CR) rate defined by PET imaging was 90%. Eight out of ten remain progression-free and 9/10 are alive at a median follow-up of 4.6 years (range: 2.1-5.3). Estimated progression-free survival (PFS) at 5 years was 79% (95% CI: 56-100%). The main toxicity was reversible myelosuppression with 80% treatment-related hematologic grade 3 or higher adverse events (AEs) (leukopenia 80%, neutropenia 80%, thrombocytopenia 40%, anemia 20%, transaminitis 20%). Rate of nonhematologic grade 3 or higher AEs was 20% (fatigue 10%, pneumonia 10%). Conclusions Frontline therapy with R2CHOP in patients with untreated FL appears to be effective and associated with acceptable toxicity. The observed PET-based CR rate and PFS were promising in this cohort. Whether R2CHOP is superior to lenalidomide/rituximab alone or standard bendamustine/rituximab will require randomized studies. Figure Estimated PFS in FL patients treated with upfront R2CHOP. Figure. Estimated PFS in FL patients treated with upfront R2CHOP. Disclosures Reeder: Celgene: Research Funding; Novartis: Research Funding; BMS: Research Funding; Millennium: Research Funding. Foran:novartis: Honoraria; Millennium Pharmaceuticals, Inc.: Research Funding; pfizer: Honoraria; karyopharm: Honoraria; medscape: Honoraria; boehringer ingelheim: Research Funding; agios: Research Funding; Cellerant: Research Funding. Nowakowski:Bayer: Consultancy, Research Funding; Morphosys: Research Funding; Celgene: Research Funding.

Abstract Waldenstrom’s macroglobulinemia (WM) is a serious and frequently fatal disorder characterized by the production of a monoclonal IgM protein, a lymphoplasmacytic infiltrate in the bone marrow, and associated symptoms including anemia, lymphadenopathy and hyperviscosity. Many of the mechanisms leading to this disease are not yet known. It is clear, however, that there is dysregulation of the balance between cell proliferation and programmed cell death. BLyS (B-lymphocyte stimulator) is a TNF family member expressed by monocytes, neutrophils, macrophages, and dendritic cells. BLyS has been shown to be critical for maintenance of normal B cell development and homeostasis, and has been found to stimulate lymphocyte growth. BLyS is overexpressed in a variety of B-cell malignancies and has been shown to inhibit apoptosis in malignant B-cells. Studies of the effects of BLyS on B cell physiology have shown that it also regulates immunoglobulin secretion. In previous work, we have shown that malignant B cells from patients with WM are able to bind soluble BLyS and variably express the BLyS receptors, BAFF-R, TACI and BCMA. We also found expression of BLyS in bone marrow specimens by immunohistochemistry and elevated serum BLyS levels in patients with WM. The goal of this study was to determine the functional role of BLyS-receptor ligand system in Waldenstrom’s macroglobulinemia and its relevance to the increased immunoglobulin production seen in this disease. Using cells from WM patients, we first examined the ability of BLyS to increase the secretion of IgM by malignant B cells. BLyS, alone or in combination with cytokines that induce plasmacytic differentiation and immunoglobulin production (IL-2, IL-6, IL-10 and IL-12), was found to increase IgM secretion by malignant B cells. Mean baseline IgM levels significantly increased in cells treated with BLyS (p=0.03), cytokines (p=0.0002) and a combination of BLyS and cytokines (p<0.0001). We then determined the effect of BLyS on the survival of malignant B cells using Annexin-V/PI staining. Compared to cells cultured in media alone, BLyS was found to increase viability of malignant B cells from WM patients. Cell viability was normalized relative to the media-alone control and the median relative viability increased significantly compared to controls (median increase 41.2%; range 8 – 46%). Next, we examined the ability of BLyS to modulate cell proliferation using thymidine incorporation. Using WM patient samples, BLyS was found to significantly enhance the proliferation of malignant B cells (p=0.0002). Furthermore, addition of anti-Ig antibody further enhanced the ability of BLyS to promote the proliferation of malignant B cells (p<0.0001). In summary, we have demonstrated that BLyS enhances IgM secretion by malignant B cells from patients with Waldenstrom’s macroglobulinemia. We have also demonstrated the ability of BLyS to enhance the survival and proliferation of malignant B cells. Strategies to inhibit BLyS may potentially have therapeutic efficacy in Waldenstrom’s macroglobulinemia.

Abstract Background: Adult T-cell acute lymphoblastic leukemia / lymphoma (T-ALL) is a rare and aggressive hematological malignancy. Unlike B-cell ALL, apart from age and presenting WBC, additional prognostic factors remain largely unknown. Additionally, the prognostic impact of a monosomal karyotype, which has a negative impact on survival in myeloid neoplasms, remains to be determined in T-ALL (Kenderian et al, BCJ 2013) Aim: To study predictors of survival including the role of a monosomal karyotype in T-ALL. Methods: After due IRB approval, adults diagnosed with T-ALL from 1990-2014 at Mayo Clinic Rochester were identified. All clinical and pathologic data including FISH studies and cytogenetics were retrospectively reviewed. Chi-square test was used to compare variables. Survival was estimated and compared using the Kaplan-Meier Method and log-rank test. Univariate and multivariate analysis was performed using the Cox regression model. Results: Between 1990 and 2014, a total of 92 consecutive patients (pts) with T-ALL were identified, 41 had acute lymphoblastic lymphoma (LBL), and 51 (55%) acute lymphoblastic leukemia (ALL). Median age at diagnosis was 33 years (range; 18-88 years) with 72%males. Median follow up of our cohort was 25 months (range; 0.9-260 months) during which time 42 deaths (45%) were documented. A. Baseline characteristics: Fifty six (67%) had constitutional symptoms, and 63 (77%) had lymphadenopathy at diagnosis. Mediastinal mass was identified in 49 (55%) pts with palpable splenomegaly in 16 (20%) pts. Fifty one (58%) pts had extranodal disease, and 17 (19%) pts had CNS involvement. Pleural and pericardial effusion were evident in 16 (19%), and 6 (7%) pts, respectively. Median laboratory values included; LDH 288 U/L (115-6590), hemoglobin (Hb) 12.8 g/dl (4.5-18.2), WBC 8.65 x109 (1.4-406), platelets 169 x109 (8-485), bone marrow blasts 29% (0-99). B. Treatments: Induction therapies were variable and included; 11 (12%) CHOP like regimens, 7 (8%) modified NHL regimens (Asparginase+CHOP), 54 (58%) ALL like regimens (CALGB 9111, E2993, or HyperCVAD), 13 (14%) Pediatric regimens (ALL 10403, CCG 1961, BFM, Augmented BFM, GRAALL 2003, or Hoelzer regimen), with 7 (8%) patients' receiving palliative care only. Seventy-one (77%) pts achieved complete remission (CR1) during induction therapy while eight pts had refractory disease (8%). Thirty-three (35%) pts underwent stem cell transplant; 7 (21%) autologous and 26 (79%) allogeneic. Forty one (44%) pts had disease relapse and median time to relapse was 10.8 months (range; 8.2-16 months) C. Predictors of survival: In univariate analysis, that included age > 60 years, leukocyte count Hb, Plt, Blast percentage, mediastinal mass, LDH and CNS involvement, only age >60 and CNS involvement were predictors of inferior survival and both retained significance in the multivariable analysis with HR 3.9 (CI 1.5 - 9; p=0.0055) and 2.8 (1.3 - 5.7; p =0.0085), respectively (Figure 1 and 2). In this cohort age >60 was a better stratification that the conventionally used age above 40 (p = 0.1). Among 56 pts with evaluable cytogenetics data, 7 (13%) pts had MK which did not have an impact on survival with HR 1.9 (CI 0.4-5.6; p=0.33). Conclusion: In this large cohort of adult T-ALL patients, we observed that age >60 years and CNS involvement were independent predictors of inferior survival. MK was infrequent, but unlike in myeloid neoplasms, does not seem to impact overall survival. Figure 1. Figure 1. Figure 2. Figure 2. Disclosures Al-Kali: Celgene: Research Funding. Thompson:Kite Pharma: Research Funding. Witzig:Novartis: Research Funding; Celgene: Research Funding; Amgen: Honoraria; Spectrum: Research Funding; Valeant Pharma: Equity Ownership.

Abstract Background: Acute T-cell lymphoblastic leukemia (T-ALL)/ lymphoma (T-LBL) are immature T-cell malignancies with very poor outcomes. In patients with relapsed disease, survival is often < 12 months (Marks et al, Blood, 2009). Prognostic correlates and treatment outcomes after relapse remain largely unknown. Aims: To evaluate prognostic correlates and treatment outcomes in patients with relapsed T-ALL/LBL. Methods: After IRB approval, 92 consecutive patients with T-cell ALL/LBL were identified. 41 patients with relapsed disease after achieving a first complete remission (CR1) were included in the study group. Features at the time of relapse were retrospectively abstracted and analyzed. Survival time after relapse was calculated from the time of relapse until death or last follow-up. Conventional methods were used for statistical analysis. Results: A. Baseline characteristics of all patients 92 patients were identified [41 LBL, 51 ALL]. Median age was 33 years (range; 18-88) and 66 (72%) were males. Median follow-up was 25 months (range 0.9-260). 13(14%) received palliative care or were lost to follow-up before treatment initiation. At last follow-up, there were 41 (52%, n = 79) relapses and 42 (46%, n = 92) deaths. Of 79 patients, 71 (90%) achieved a CR1 and 8 (10%) had primary refractory disease. Comparisons between ALL and LBL revealed expected differences in presenting features such as frequency of primary mediastinal mass at presentation in LBL and high leukocyte count in ALL. Significant differences in treatment were seen. Asparaginase-based and ALL-directed therapy were more common in the ALL group (71% vs. 45%, p = 0.009; 88% vs. 71%, p = 0.04). 13 (81%) LBL and 14 (27%) ALL underwent allogeneic SCT. The remaining three in each group underwent autologous SCT in CR1. B. Characteristics of relapsed patients 41 relapsed after achieving CR1 [23 LBL, 18 ALL]. Median time to relapse was 8.0 months (range 2.3-130), with no difference between ALL and LBL groups. Median age was 34 years (range 19-71) and 29 (71%) were males. Median follow-up after relapse was 7.2 months (range 0.3-207). At time of last follow-up, there were 30 (73%) deaths, 25 (61%) achieved a second complete remission (CR2) and 14 (34%) had persistent disease. 12 (48%) had relapse following CR2. 34 (83%) relapsed following CR1 after induction chemotherapy alone. 6 (15%) and 1 (2%) relapsed following allogeneic and autologous SCT respectively. 27 (66%) had BM involvement, 5 (12%) had CNS involvement, 13 (32%) had mediastinal involvement, and 3 (7%) had isolated extramedullary relapse. Ten (43%) patients with LBL relapsed with ALL. Of 27 patients with available data, 9 (33%) had high-risk cytogenetics at relapse, defined as ≥ 5 chromosomal abnormalities and/or markers known to confer an unfavorable prognosis. 16 of these 27 patients had follow-up cytogenetic studies performed, of which 8 (50%) had evidence of clonal evolution. Patients were treated with up to five regimens. 12 (31%) received asparaginase-based therapy and 13 (33%) received nelarabine with CR2 rates of 75% and 25% respectively. Median number of regimens needed to achieve CR2 was one. 18 (46%) went onto SCT following CR2: 14 (allogeneic), 3 (autologous), and 1 (donor lymphocyte infusion). The majority received myeloablative conditioning (92%). C. Outcomes and prognostic correlates for survival after relapse Median survival following relapse was 8.2 months (IQR 4.1-21.3) and did not differ between LBL and ALL. Nine (36%) who achieved CR2 are alive at time of last follow-up. 25 (61%) achieved CR2, but 12 (48%) relapsed following CR2, with median time to second relapse of 7.6 months (IQR 4.7-14). Nine of 18 who underwent SCT following CR2 had disease relapse (8 allogeneic, 1 autologous). Only BM involvement at relapse significantly correlated with post-relapse survival (HR 2.4 [1.1, 5.1], p = 0.03). Clonal evolution, high-risk cytogenetics, nelarabine therapy, achieving CR2, and SCT were not independent predictors of survival in our small subset of patients. Conclusion: Patients with relapsed T-ALL/LBL have dismal outcomes, in spite of advances in therapy with newer agents such as nelarabine and the use of allogeneic SCT. Regardless of T-ALL/LBL subtype, BM involvement at relapse appears to be a significant factor negatively impacting post-relapse survival. Further studies are needed to validate these findings. Disclosures Al-Kali: Celgene: Research Funding. Thompson:Kite Pharma: Research Funding.