ALBERT

Description: Key Points Plasma EBV-DNA is highly concordant with EBV tumor status in Hodgkin lymphoma. Plasma EBV-DNA has prognostic significance in Hodgkin lymphoma, both before therapy and at month 6 of follow-up.

Description: Abstract 98 Background: Advanced follicular lymphomas (FL) are incurable with conventional chemotherapy and there is no consensus on the best treatment approach. The SWOG cancer research cooperative group and Cancer and Leukemia Group B (CALGB) compared the safety and efficacy of two immunochemotherapy regimens for FL in a Phase III randomized intergroup protocol (S0016) that enrolled 554 patients with previously untreated, advanced stage FL between 3/1/2001 and 9/15/2008. Methods: Pts were eligible if they had advanced stage (bulky stage II, III or IV) evaluable FL of any grade (1, 2, or 3) and had not received any prior therapy. In one arm (CHOP-R), patients received 6 cycles of CHOP chemotherapy (750 mg/m2 cyclophosphamide, 50 mg/m2 doxorubicin, 1.4 mg/m2 vincristine, and 100 mg prednisone daily for 5 days) at 3 week intervals with 6 doses of rituximab anti-CD20 antibody (375 mg/m2 on days 1, 6, 48, 90, 134 and 141 according to the schedule described by Czuczman et al.[J.Clin.Oncol 17:268, 1999]). In the second arm of the protocol, patients received 6 cycles of CHOP, followed by a dosimetric infusion of tositumomab/iodine I-131 tositumomab and then 1–2 weeks later a therapeutic infusion of I-131-tositumomab labeled with sufficient I-131 (median 85 mCi) to deliver a total body dose of 75 cGy (CHOP-RIT). The study was designed to have 86% power to detect a hazard ratio (HR) of CHOP-RIT to CHOP-R of 0.67 for 2 yr PFS based on a one-sided.021 level test (accounting for 3 interim analyses). Results: Of the 554 enrolled pts, 532 were eligible and 526 were evaluable for toxicity (263 on each arm of the protocol). Pt characteristics (age, sex, race, stage, beta 2 microglobulin level, tumor bulk, B symptoms) were well-balanced in the two arms of the protocol. In general, both regimens were well-tolerated (Table I). Median follow-up time among patients still alive is 4.9 years. One hundred and six of 267 eligible pts on the CHOP-R arm have progressed or died compared to 86 of 265 eligible pts on the CHOP-RIT arm. The 2 year estimate of PFS was 76% on the CHOP-R arm and 80% on the CHOP-RIT arm (Figure 1). In multivariate Cox regression adjusting for the stratification factor (serum beta-2 microglobulin level), the hazard ratio for CHOP-RIT vs. CHOP-R was 0.79 (95% CI: 0.60–1.05, p=.11 [2-sided] or p=.06 [1-sided]). Twenty-six of 267 pts on the CHOP-R arm have died compared to 40 of 265 eligible pts on the CHOP-RIT arm. The 2-year estimate of overall survival was 97% on the CHOP-R arm and 93% on the CHOP-RIT arm. In multivariate Cox regression adjusting for the stratification factor serum beta-2 microglobulin, the hazard ratio for CHOP-RIT vs. CHOP-R was 1.55 (95% CI: 0.95–2.54, p=.08 [2-sided]). Conclusion: No statistically significant differences in PFS, OS, or serious toxicities are yet demonstrable with either regimen administered in this trial. However, PFS and OS are outstanding with either of the two regimens with median times to progression not yet reached for either treatment. Future studies will be needed to assess whether combining CHOP-R with RIT consolidation and with maintenance rituximab will confer additive benefit, as being evaluated in a follow-up trial (SWOG protocol S0801) that has recently completed accrual. Disclosures: Press: Spectrum: Consultancy, Honoraria; Roche/Genentech: Consultancy, Honoraria, Research Funding. Off Label Use: Front-line use of I-131-tositumomab for consolidation therapy in 1st remission of follicular lymphoma. Friedberg:Genentech: Consultancy, Honoraria. Czuczman:Glaxo Smith Kline: Consultancy, Research Funding; Genentech: Consultancy, Honoraria. Kaminski:Glaxo Smith Kline: Patents & Royalties. Maloney:Genentech/Roche: Consultancy, Honoraria, Speakers Bureau; Glaxo Smith Kline: Consultancy, Honoraria, Speakers Bureau. Cheson:Glaxo Smith Kline: Research Funding. Fisher:Roche: Consultancy, Honoraria.

Description: Abstract 1703 Myleodysplastic syndrome (MDS) is a heterogeneous group of clonal hematopoietic diseases marked by various cytopenias including neutropenia and anemia. Hematologic improvement in response to T-cell depleting agents and immunosuppressants in a subset of MDS patients suggests that hematopoietic impairment may result from autoreactive T-cell activation. Conversely, suppression of the T-cell compartment may be permissible to the development of malignant myeloid clones. The suspicion that T-cell homeostatic balance may be disrupted in MDS has spawned numerous studies investigating mechanisms of immune suppression and autoimmune regulation. T-cell autoimmunity is regulated in part by regulatory T-cells (Tregs), which express T cell receptors (TCRs) that recognize self-antigens and function to maintain immune homeostasis. Indeed, higher numbers of Tregs have been found in higher risk MDS patients, and those MDS subtypes with higher blast percentages. However, the role of Tregs in lower risk patients is less clear, but may still represent an important component of pathogenesis in early disease. Because of the autoimmune nature of low risk MDS, we hypothesized that alterations in the Treg compartment may play a role in lower risk MDS disease progression. To address this, we analyzed Treg phenotype and numbers in MDS patients largely classified as low risk by the International Prognostic Scoring System (IPSS) and 41 age-matched controls using cell surface markers as analyzed by flow cytometry. Tregs were identified as CD3+CD4+CD25+CD127dim. The use of CD127 as a Treg marker was validated by intracellular staining with FoxP3. Naïve and memory phenotypes within the Treg compartment were analyzed using CD45RA and CD27 expression. Naïve Tregs (TregN) were characterized as CD45RA+CD27+, central memory Tregs (TregCM) as CD45RA−CD27+, and effector memory Tregs (TregEM) as CD45RA−CD27−. Two distinct subgroups of MDS patients were identified: one with elevated total numbers of Tregs, and a second with a marked shift in Treg memory phenotype away from the common TregCM phenotype and toward the rare TregEM phenotype. These two subgroups of patients were distinct from each other, and appeared to be independent of MDS WHO subtype, IPSS score, karyotype, neutropenic state, and thrombocytopenic state. MDS patients with a shift toward TregEMwere associated with anemia (p=0.0433). This association was not found in MDS patients with total increases in Treg numbers. Next, we sought to determine if there are differences in overall survival (OS) of MDS patients with either increased total numbers of Tregs or in patients with a shift toward TregEM phenotype. Patients with greater than 50 Tregs/μl did have reduced OS compared to patients with less Tregs, but this difference was not statistically significant (p=0.1387). In contrast, a highly significant difference was observed in MDS patients with a shift toward the TregEM phenotype (p=0.0200), with patients having greater than 2.5TregEM/μl displaying the worst OS (Figure 1). Figure 1 Overall Survival in lower risk MDS patients with Low, Intermediate, or High absolute numbers of TregEM cells Figure 1. Overall Survival in lower risk MDS patients with Low, Intermediate, or High absolute numbers of TregEM cells Lastly, because an increased TregEM compartment is associated with reduced OS in MDS patients, we sought to compare the suppressive capacities of TregN, TregCM, and TregEM cells to better understand the functional consequences of Treg memory shift. CD4+ T-cells were isolated by negative selection, and then TregN, TregCM, and TregEM cells were sorted using CD45RA and CD27 expression. Conventional CD4+ responder cells were then labeled with Carboxyfluorescein succinimidyl ester (CFSE) and co-cultured with increasing ratios of each isolated Treg population. Cellular division in response to CD3/CD28 stimulation was measured 5 days later by analyzing CFSE dilution. TregCM appear to be the least suppressive, while TregN and TregEM cells were more potently suppressive. These results indicate that a shift in Treg phenotype toward TregEM may result in a more suppressive Treg compartment without obvious increases in total Treg numbers. Taken together, this data suggests that in lower risk MDS, the phenotypic makeup of the Treg compartment may be more important than total Treg numbers. In addition, this data suggests that increased TregEM cells may be a novel prognostic indicator in low risk MDS. Disclosures: Komrokji: Celgene: Honoraria, Research Funding, Speakers Bureau. List:Celgene: Consultancy.

Description: Abstract 3625 Background: SL-401 is a novel biologic targeted therapy, comprised of human IL-3 coupled to a truncated diphtheria toxin payload that inhibits protein synthesis, directed at the interleukin-3 receptor (IL-3R). IL-3R is overexpressed on leukemia blasts and cancer stem cells (CSCs) relative to normal hematopoietic cells. Since SL-401 uniquely targets both the leukemia blasts (tumor bulk) and CSCs, it would be expected to induce tumor regression (anti-tumor bulk effect), as well as inhibit tumor repopulation (anti-CSC effect), thereby improving survival. SL-401 has been evaluated in a Phase 1/2 clinical trial in patients with advanced hematologic cancers. In this study, SL-401 has demonstrated objective clinical responses, including durable complete responses (CRs) and protracted overall survival (OS) in patients with heavily pretreated AML. The current report is a final analysis of the patients with AML or MDS. Study Design: Seventy-eight patients with advanced hematologic cancers, including relapsed or refractory AML (n = 59), de novo AML unfit for chemotherapy (n = 11), high-risk MDS (n = 7), and other (n = 1), were enrolled in a multicenter study. Among the patients with relapsed or refractory AML, the numbers of patients receiving SL-401 as 2nd, 3rd, or 〉3rd line therapy were 24, 16, and 19, respectively. The median (range) age for AML patients was 65 (7, 84) years. Patients received SL-401 as a 15-minute intravenous infusion in one of two dosing regimens for a single cycle to determine the maximum tolerated dose (MTD) and assess antitumor activity. In Regimen A, 45 patients received doses ranging from 4 to 12.5 μg/kg every other day for up to 6 doses. In Regimen B, 33 patients received doses ranging from 7.1 to 22.1 μg/kg daily for up to 5 doses. Results: A single cycle of SL-401 demonstrated single agent activity in patients with relapsed or refractory AML, including 2 durable CRs of 8 and 〉25 months duration and 5 partial responses (PRs). OS was also notable among patients who received one cycle of SL-401 as ≥3rd line therapy for AML; the median OS was 3.6 (2.3, 6.1) months. Moreover, at therapeutically relevant doses, defined as the MTD or one or two dose levels below the MTD (9.4, 12.5, or 16.6 μg/kg/day), the median OS among AML patients who received SL-401 as ≥3rdline therapy (n = 16) was 5.6 (2.5, 10.8) months. These OS values compared favorably to historical results of 1.5 months for patients treated with standard chemotherapy. SL-401 was well tolerated. The MTD was not achieved with Regimen A, whereas the MTD for Regimen B was 16.6 μg/kg/day, with manifestations of capillary leak syndrome, including hypoalbuminemia and edema, as the dose-limiting toxicity (DLT) at the 22.1 μg/kg/day dose level. Transient (i.e., lasting ≤2 weeks) transaminase elevations were among the most common ≥Grade 3 AEs. Notably, there was no evidence of treatment-related bone marrow suppression. Conclusion: SL-401 demonstrated single agent anti-tumor activity and was well tolerated in patients with advanced AML. Improved survival was observed among patients who received a single cycle of SL-401 as ≥3rd line treatment, a disease setting in which there is no standard therapy. SL-401 may be an attractive treatment option for these patients given their tendency to be myelosuppressed and therefore are often poor candidates for myelosupressive therapies that have limited benefit on clinical response and survival in this setting. Based on these positive findings, SL-401 will be advanced into a randomized Phase 2b trial to treat patients with AML in the 3rd line setting. Patients will be randomized to treatment with either multiple cycles of SL-401 or physician's choice, which will consist of available standard therapeutic agents. In addition, the efficacy and safety of SL-401-based combination therapy will also be studied in earlier lines of AML given the lack of overlapping toxicities with existing hematologic cancer therapies. Disclosures: Konopleva: Stemline Therapeutics: Research Funding. Cirrito:Stemline Therapeutics: Employment, Equity Ownership, Patents & Royalties. Hoberman:Stemline Therapeutics: Employment, Equity Ownership. Szarek:Stemline Therapeutics: Consultancy, Equity Ownership. Rowinsky:Stemline Therapeutics: Employment, Equity Ownership. Bergstein:Stemline Therapeutics: Employment, Equity Ownership, Patents & Royalties. Frankel:Stemline Therapeutics: Research Funding.

Description: Key Points Clinical responsiveness to imexon represents the first demonstration of efficacy with modulating cellular redox in B-cell NHL. Antioxidant-related gene expression predicted for response to imexon.

Description: Abstract 3737 Background: Hodgkin lymphoma (HL) is among the most curable lymphomas, however 20%-30% of patients relapse after initial chemotherapy, or have primary refractory disease. While 30–50% of these patients may be cured with second line chemotherapy and autologous stem cell transplant, patients who do not obtain a complete response (CR) prior to transplantation, or who relapse after second line therapy have few effective therapeutic options. Novel treatment strategies for these patients are needed. It has been previously shown that in patients with classical HL the malignant Hodgkin Reed-Sternberg cells (HRS) express a high level of the Interleukin-3 receptor (IL-3R). Therefore, we hypothesized that SL-401, a novel biologic conjugate consisting of IL-3 linked to diphtheria toxin, which targets IL-3R, may be an effective approach for selectively targeting and killing HRS cells. Methods: We first assessed the expression of the IL-3R α-chain (CD123) on two nodular sclerosing (HDLM-2 and L-428) and two mixed cellularity (KM:H2 and L-1236) HL cell lines by flow cytometry. Cells were washed with PBS and stained with CD123 PE (BD Pharmingen) as well as other antibodies, including CD15 FITC (BD Pharmingen), for 20 minutes at 4°C and again washed with PBS. Stained cells were acquired using the LSR II (BD) and data were analyzed using Flow Jo (Tree Star). We then tested the sensitivity of these cell lines to SL-401 using a CellTiter Glo in vitro cytotoxicity assay. A CD123 positive eyrthroleukemic cell line (TF-1/H-ras) with known sensitivity to SL-401 was used as a positive control. The cell lines were cultured in the presence or absence of SL-401 for 48 h and assessed for cell viability at concentrations ranging from 3×10−7 to 1.3 μg/ml. Results: We found high expression of CD123 on HDLM-2 and L-428 HL lines (99% and 89%, respectively) and low-to-moderate expression of the receptor on the L1236 and KM-H2 lines (19.5% and 1%, respectively). Based on CD123 expression, we assessed the sensitivity of these cell lines to SL-401. The L428 and HDLM2 cell lines, which exhibited a high expression of CD123, showed sensitivity to SL-401 relative to control starting at approximately 0.3 ng/ml. Cell viability was reduced to 64.8 ± 5% for L-428 and 68.2 ± 8% for HDLM2 when incubated at the highest concentration of drug (1 μg/ml (L428) and 0.7 μg/ml (HDLM2)). The low CD123 expressing cell lines L1236 and KM:H2 were less sensitive to SL-401 and did not exhibit a significant reduction in cell viability even at the highest concentration of SL-401 tested (1.3 ug/ml; 100 ± 2% and 88.4 ± 6%, respectively). Other lymphoid malignant cell lines with CD123 expression reported in the literature were also tested. Interestingly, the T Acute Lymphocytic Leukemia (T-ALL) cell lines DND41 and P12 showed marked sensitivity to SL-401, with a reduction in cell viability to 55.9 ± 4% and 47.9 ± 6%, respectively, in the presence of 1.3 μg/ml of drug. Conclusion: These results suggest that CD123 expression may vary as a function of HL histology, and that sensitivity to SL-401 may correlate with CD123 expression. Based on these results, SL-401, which is currently being evaluated in clinical trials of patients with acute myeloid leukemia, myelodysplastic syndrome, and chronic myeloid leukemia, may be a potential treatment strategy in refractory HL, and warrants further exploration in T-ALL. Exploration of CD123 expression in primary and relapsed/refractory patients with lymphoid malignancies as well as in vivo studies with SL-401 in this setting is currently underway. Disclosures: Brooks: Stemline Therapeutics, Inc: Employment, equity options. Cirrito:Stemline Therapeutics Inc.: Employment, Equity Ownership, Patents & Royalties. Bergstein:Stemline Therapeutics Inc.: Employment, Equity Ownership, Patents & Royalties. O'Connor:Merck: Research Funding; Spectrum: Research Funding; Novartis: Research Funding; Celgene: Consultancy, Research Funding.

Description: 5271 Cold agglutinin disease is an autoimmune hemolytic anemia mediated by cold reactive autoantibodies triggering a complement mediated hemolysis. This condition, when not associated with infection, is characterized by clonal proliferation of CD20+ B cells that produce monoclonal IgM cold agglutinins. Conventional therapies for primary cold agglutinin disease (CAD) are ineffective, but case reports suggest that rituximab, an anti-CD20 monoclonal antibody, may be effective. In this retrospective single institution study, we evaluated the use of rituximab therapy in 6 patients (pts) [1 male, 5 female; median age 70 years (range 62 – 89)]. Three pts had primary CAD, 2 pts had mixed CAD and warm AIHA, and 2 pts had CAD in the setting of CLL. Five pts had received steroid therapy, 2 pts IVIG, 1 pt azathioprine, and 5 pts PRBC transfusion (2–10 units). Five received induction therapy with rituximab 375 mg/m2 IV weekly for four weeks and 1 for seven weeks. Four patients received maintenance rituximab 375 mg/m2 IV every two months (4+ to 12 cycles). All responded to therapy with a median rise in hemoglobin of 1.8 g/dl at 2 months from initiation of induction with further improvement over time (figure 1). Re-induction was performed in 2 pts; both had an initial one year duration of response and both responded following re-treatment. Median duration of response is 3+ yrs (range 1–8+ yrs); the 8+ yr response was in pt 2 who received only induction therapy. Two pts have completed two years of maintenance therapy and remain in remission at 4 months and 2 years post, respectively. Cold agglutinin titers decreased by 4 fold in 2 patients, 1 fold in 1 pt and remained stable in 1. Despite the improvement in hgb in all pts, laboratory evidence of low grade hemolysis persisted in 4 pts. All pts were able to be tapered off steroids and all remain transfusion free. No unexpected adverse events were noted. Rituximab appears to be a well tolerated and effective therapy for cold agglutinin disease. The need for and length of maintenance therapy remains to be determined. Disclosures: No relevant conflicts of interest to declare.

Description: The natural killer (NK) type of aggressive large granular lymphocytic (LGL) leukemia is a fatal illness that pursues a rapid clinical course. There are no effective therapies for this illness, and pathogenetic mechanisms remain undefined. Here we report that the survivin was highly expressed in both aggressive and chronic leukemic NK cells but not in normal NK cells. In vitro treatment of human and rat NK-LGL leukemia cells with cell-permeable, short-chain C6-ceramide (C6) in nanoliposomal formulation led to caspase-dependent apoptosis and diminished survivin protein expression, in a time- and dose-dependent manner. Importantly, systemic intravenous delivery of nanoliposomal ceramide induced complete remission in the syngeneic Fischer F344 rat model of aggressive NK-LGL leukemia. Therapeutic efficacy was associated with decreased expression of survivin in vivo. These data suggest that in vivo targeting of survivin through delivery of nanoliposomal C6-ceramide may be a promising therapeutic approach for a fatal leukemia.

Description: S0515 was a phase 2 trial to determine whether the addition of bevacizumab to cyclophosphamide, doxorubicin, vincristine, prednisone (CHOP) plus rituximab (R-CHOP) would improve progression-free survival (PFS) without adding significant toxicity in patients with newly diagnosed advanced diffuse large B-cell lymphoma. A total of 73 patients were enrolled. For the 64 eligible patients, median age was 68 years, and 60% had International Prognostic Index scores more than or equal to 3. The observed 1- and 2-year PFS estimates were 77% and 69%, respectively. These PFS estimates were not statistically different from the expected PFS for this population if treated with R-CHOP alone. Grade 3 or higher toxicities were observed in 81% of patients, including 2 grade 5 events. The majority of serious toxicities were hematologic but also included 5 patients with gastrointestinal perforations, 4 patients with thrombotic events, and 11 patients who developed grade 2 or 3 left ventricular dysfunction. Higher baseline urine VEGF and plasma VCAM levels correlated with worse PFS and overall survival. In conclusion, the addition of bevacizumab to R-CHOP chemotherapy was not promising in terms of PFS and resulted in increased serious toxicities, especially cardiac and gastrointestinal perforations. This study is registered at www.clinicaltrials.gov as #NCT00121199.

Description: Abstract 321 Gene expression profiling of newly diagnosed diffuse large B-cell lymphomas shows a correlation between the expression of oxidative stress-related genes and patient prognosis following chemotherapy. Anthracyclines and cyclophosphamide used in lymphoma therapy are known to work, at least in part, through oxidative stress. We hypothesized that single nucleotide polymorphisms (SNPs) in oxidative stress-related genes may contribute to clinical outcomes and/or the development of hematologic toxicities for patients treated with curative intent anthracycline-based therapies for aggressive B-cell Non-Hodgkin lymphomas. Our study involved 473 patients enrolled in 7 prior Phase II or Phase III Southwest Oncology Group clinical trials. DNA for the SNP analyses was obtained from banked, paraffin-embedded diagnostic tissue. Genotyping was performed for 72 SNPs in 33 oxidative stress-related genes. After excluding pathologically or clinically ineligible patients and those with SNP call rates