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Abstract Despite advances in treatments for patients with non-Hodgkin’s lymphoma (NHL), the relapse rates remain high and 40% of diffuse large B-cell NHL (DLBCL) patients die of disease. New therapies to augment the host anti-tumor immune response are needed. Reports of graft-versus-lymphoma responses in patients who have received allogeneic hematopoietic cell transplant indicate a role for cellular immunotherapy. However, these patients have variable levels of immunodeficiency which may impact the efficacy of cellular therapy. To study this we first evaluated the cellular immune status of patients with relapsed NHL. Proliferation of peripheral blood mononuclear cells (PBMNC) stimulated with anti-CD3/CD28 beads was reduced by more than 3.5 folds for patients with DLBCL (n = 3) compared to that of age-matched healthy donors (n = 5; p = 0.02). Removal of monocytes from PBMNC by use of anti-CD14 immunomagnetic beads restored proliferation to that of healthy donors. Further, monocytes from these patients were deficient in stimulating allogeneic T cell proliferation by 3 folds compared to monocytes from healthy donors (n = 3 NHL; n = 8 normal; p < 0.01). Peripheral blood from 12 NHL patients (9 DLBCL; 1 grade 3 follicular lymphoma; 2 composite) and 12 age-matched healthy donors were characterized by flow cytometry to determine the phenotype of these suppressive monocytes. There was no difference in the % monocytes in the blood between NHL patients and healthy donors; however, NHL patients had elevated % monocytes with a suppressive phenotype (CD14+HLA-DRneg) compared to normals (NHL 38.9 ± 4.93%; normal 8.3 ± 2.15; p < 0.0001). This phenotype is distinct from other myeloid suppressors (Lin-CD33+HLA-DR-) or non-classical monocytes (CD16+), neither of which was different in numbers between NHL and normal donors. This suggests that the CD14+HLA-DRneg monocytes are responsible for the observed T cell suppression. To further characterize the function of these cells, we cultured purified CD14+ monocytes from NHL and compared their differentiation capacity with those from normal donors. The percentage of CD14+HLA-DRneg monocytes in initial ex vivo culture was inversely correlated with the percentage of pure, mature dendritic cells (mDC) generated with TNF-a and PGE2 as maturation factors (CD80+CD83+; n = 9; p = 0.015). As CpG oligonucleotides are also capable of immune stimulation and have some anti-tumor activity in clinical trials, we investigated the effect of CpG on mDC differentiation in NHL. In healthy donors, maturation of monocytes with CpG yielded highly pure mDC (90.7 ± 2.15%, n = 3). However, preliminary results of mDC yield from monocytes of NHL patients matured with CpG was only 22.6 ± 11.2% (n = 2). This data suggests alternative signaling pathways of these suppressive monocytes. Preliminary analysis of a proteome array for 46 kinase phosphorylation sites from 37 proteins in 2 NHL and 3 healthy donors suggest changes in phosphorylation of 17 protein kinases for CD14+HLA-DRneg compared to CD14+HLA-DR+ cells. Functional correlation of these protein kinase phosphorylation changes is needed to definitively target the pathway characteristic of CD14+HLA-DRneg monocytes. Finally, we have identified a serum-free culture method that can consistently generate highly pure mDC from monocytes of NHL patients (93.0 ± 3.6%, n = 9) and is readily adaptable to good manufacturing practice for clinical use in immunotherapy. Taken together we have described for the first time a population of CD14+HLA-DRneg monocytes that is a significant source of immunosuppression in NHL patients and are beginning to target methods of overcoming this suppression.

Abstract Previous work has suggested a relationship between disease activity and in vivo birth rates of chronic lynphocytic leukemia (CLL) cells, as measured by incorporation of deuterium into DNA during heavy water (2H2O) consumption. By extension, CLL-cell kinetics may be a useful prognostic marker in early stage disease, with an increased birth rate predicting shorter time to disease progression and poor prognosis. We are conducting a multi-center study to evaluate the relevance of proliferation rates to both known prognostic markers and to disease progression during 2.5 years of clinical follow up in previously untreated patients with early stage disease. Patients are given a daily dose of 2H2O for 6 weeks and CLL-cell birth rates are measured. We examined the leukemia cells of 36 patients for known prognostic markers (ZAP 70 expression, CD38 expression, IgVH mutation status) and CLL birth rates. Subjects were Rai Stage 0 (n=15), 1 (n=17), or 2 (n=4); mean age 57 +/− 9 (range 41–78); mean time from diagnosis to enrollment 2.1 +/− 2.2 y (range 0.1–10 y). ZAP-70 expression (20% cutoff) was positive in 44%, CD38 expression (30% cutoff) was positive in 35%, and use of unmutated IgVH genes was found in 45% of the subjects. CLL-cell birth rates ranged from 0.09 to 0.97% per day. Utilizing the previously published cut-off value of 0.35% newly divided cells per day, 33% of subjects had a high proliferation rate. Data on all biomarkers were available for 33 subjects. Nine subjects had 4/4 favorable prognostic indicators and 5 subjects had 4/4 unfavorable prognostic indicators. Agreement between prognostic markers, as assessed by kappa coefficient, was strongest for the ZAP-70 v. IgVH mutational status comparison. Comparisons were also significant for ZAP-70 v. CD38 and IgVH mutational status v. CD38. Birth rate was not significantly correlated with any of the other prognostic markers, suggesting it may be a useful independent predictor of disease progression. Isolation of CLL-cells from the bone marrow at the end of the 6 wk labeling period in 5 subjects revealed matching proliferation rates in the marrow and blood in 3 subjects. In 2 subjects, marrow enrichment was lower, suggesting a more slowly proliferating pool in the marrow, the pathophysiologic significance of which is unclear. In 5 subjects, kinetic analysis revealed a very delayed entry of newly divided cells into the blood compartment, presumably from tissue sites of proliferation. This parameter may reflect pool size of CLL-cells in tissues and correlation with lymph node burden is being evaluated. In summary, analysis of CLL-cell birth rates in vivo in these early stage patients provides unique information about the biology of CLL. Correlations with disease progression during the follow-up period will help determine the utility of this test as a prognostic biomarker.

Abstract Abstract 3701 Background: Waldenstrom's macroglobulinemia (WM) is an indolent B-cell non-Hodgkin's lymphoma (B-NHL) characterized by production of a monoclonal IgM paraprotein and variable CD20 expression due to the downregulation of CD20 as B cells differentiate into plasma cells. Rituximab monotherapy (R) achieves an overall response rate (ORR) of 25–50% in therapy naïve and relapsed WM and is associated with IgM flares in 25–75% of patients (pts) that potentially lead to hyperviscosity due to a rapid rise in IgM. Ofatumumab (OFA) is a fully human monoclonal anti-CD20 antibody approved for the treatment of fludarabine and alemtuzumab-refractory chronic lymphocytic leukemia (CLL) and has demonstrated activity in indolent B-NHL. Since OFA is active in CLL, with its low CD20 expression, we initiated a phase II single-arm trial of OFA in pts with WM. We report primary endpoint data from this study. Methods: Pts (age ≥ 18 years) with WM requiring therapy by 2nd International Workshop on WM (IWWM) criteria were eligible. Cycle 1 (C1) of therapy consisted of OFA 300 mg week 1 and 1000 mg weeks 2–4 (Treatment Group A [TGA]) or OFA 300 mg week 1 and 2000 mg weeks 2–5 (TGB). Premedication included acetaminophen and antihistamine (all infusions) and glucocorticoid (infusions 1 and 2). Pts with grade 3–4 infusion-related adverse events (AEs) during weeks 1 and 2 also received glucocorticoid during weeks 3–5. Pts with stable disease (SD) or a minor response (MR) at week 16 of cycle 1 were eligible to receive a re-dosing cycle (C2) consisting of OFA 300 mg week 1 and 2000 mg weeks 2–5. The primary endpoint was ORR assessed by 3rd IWWM criteria. Toxicity was assessed according to NCI-CTCAE, v 3.0. Results: Thirty-seven pts were enrolled between March 2009 and February 2011. Median age was 63 years (range 43–85); 22 pts were male. Median IgM level was 3.11 g/dL (range 0.81–8.64); median hemoglobin (hgb) was 9.8 g/dL (range 5.3–13.2). Nine pts were treatment naïve; 28 pts had received a median of 3 prior therapies (range 1–5) including R (25 pts) and purine analog (14 pts). The first 15 pts were enrolled in TGA and the next 22 pts in TGB; pt characteristics were similar in both groups. Thirty-four pts completed C1; 1 pt withdrew after 1 dose and 2 pts received only 3 doses due to serious AEs (SAEs). Eleven pts achieved partial response (PR) and 7 achieved MR after C1 (ORR=49%; 95% CI [32%, 66%]). Twelve pts received C2, after which 4 pts improved their response (1 MR to PR, 1 SD to PR, 2 SD to MR) and 1 nonevaluable pt attained MR. After C1 and C2, the ORR was 59% (13 PR, 9 MR; 95% CI [42%, 75%]). Responses were seen in 67% (6/9) of therapy naïve pts, 57% (16/28) of relapsed pts, 52% (13/25) of pts who had prior R, 75% (9/12) of R-naïve pts, 64% (16/25) of pts with IgM < 4 g/dL and 50% (6/12) of pts with IgM ≥ 4 g/dL. ORR was 47% (7/15) in TGA and 68% (15/22) in TGB. ORR in TGA was negatively affected by prior R exposure and IgM ≥ 4 g/dL, whereas ORR in TGB was not affected by prior therapy, prior R or IgM level. Fifteen of 26 (58%) pts with hgb < 11.0 g/dL experienced ≥ 3.0 g/dL increase in hgb (range 3.0–7.1). Infusion-related events occurred with dose 1 in 30 (81%) pts and with dose 2 in 21 (57%) pts; all infusion events were grade 1–2 except 4 grade 3 events (1 rash, 1 chest pain, 1 chest discomfort, 1 back pain). Fifteen pts developed 22 infections including 8 upper respiratory tract, 4 urinary tract (UTI) and 4 sinus infections; all infections were grade 1–2 except 1 grade 3 UTI. One pt developed grade 3 febrile neutropenia. In total, there were 14 grade 3–4 AEs (all grade 3). Five pts developed 8 SAEs possibly related to OFA. One pt withdrew due to grade 3 hemolytic anemia. Two pts with baseline IgM of 6.63 and 4.75 g/dL required plasmapheresis for grade 3 renal insufficiency and hyperviscosity symptoms, respectively, with resolution of symptoms and were able to complete C1. Two pts developed IgM flare, defined as > 25% rise in IgM followed by subsequent MR or PR. Conclusions: OFA is clinically active in pts with WM, with an acceptable toxicity profile and a lower incidence (5%) of IgM flare. The ORR to OFA was 59% (TGA 47%, TGB 68%) including a 50% ORR (TGA 17%, TGB 83%) in pts with IgM ≥ 4.0 g/dL. Pts' anemia responded to OFA with 58% of pts with baseline hgb < 11.0 g/dL experiencing ≥ 3.0 g/dL increase in hgb. TGB achieved ORR > 60% in all pt groups regardless of prior therapy or baseline IgM level. A higher dose of OFA appeared to be more effective in pts previously exposed to R or with baseline IgM ≥ 4.0 g/dL. Further study of OFA in WM is warranted. Disclosures: Furman: Genentech: Speakers Bureau; GlaxoSmithKline: Speakers Bureau. Off Label Use: • Ofatumumab is an anti-CD20 monoclonal antibody approved for the treatment of fludarabine- and alemtuzumab-refractory chronic lymphocytic leukemia, and is currently under development for the treatment of B-cell malignancies (chronic lymphocytic leukemia, diffuse large B-cell lymphoma, Waldenstroms macroglobulinemia and follicular lymphoma), as well as autoimmune diseases (rheumatoid arthritis and multiple sclerosis). Eradat:Millennium: Speakers Bureau; Genentech, A Roche Company: Speakers Bureau. DiRienzo:GlaxoSmithKline: Employment. Leonard:GlaxoSmithKline: Consultancy. Advani:GSK: Research Funding. Switzky:GlaxoSmithKline: Employment. Liao:GlaxoSmithKline: Employment. Shah:GSK: Employment. Lisby:Genmab A/S: Employment. Lin:GlaxoSmithKline: Employment.

Abstract Background Despite improvements in outcome following the addition of rituximab (R) to CHOP (cyclophosphamide, doxorubicin, vincristine, prednisone) (R-CHOP), patients with newly diagnosed diffuse large B-cell lymphoma (DLBCL) and International Prognostic Index (IPI) scores of 3-5 at diagnosis have a poor outcome. Enzastaurin is a potent inhibitor of PKCβ, a component of the B-cell receptor signaling complex, with preclinical activity and clinical activity in a phase II trial in patients with relapsed DLBCL, providing the rationale for this study in the primary therapy setting. Methods PRELUDE was a multi-national, randomized, double-blinded, placebo-controlled study. Patients were required to have a histologic diagnosis of DLBCL, pre-treatment IPI score ≥3, and a complete response (CR) or CRu by International Working Group Criteria, or a negative FDG-PET scan after 6–8 cycles of R-CHOP. Patients were randomly assigned in a 2:1 ratio to receive either enzastaurin 500 mg daily or an identical placebo as maintenance therapy, for a planned treatment duration of 3 years. The primary endpoint was DFS, defined as lack of disease progression or death. Assuming a 2-year DFS rate in the control group of 70%, the primary analysis had 80% power to detect a HR of 0.67, eg, a 2-year DFS rate of 79% in the enzastaurin group. Secondary endpoints included overall survival (OS) and event-free survival (EFS). Data were analyzed 3 years after the last enrolled patient initiated treatment. Results From May 2006–April 2010, 758 patients were enrolled (enzastaurin, n=504; placebo, n=254). Median age at enrollment was 64 years (range 21-89); at diagnosis, 65% of patients had stage IV disease, 48% had B symptoms, and 25% had a mass >10 cm; baseline disease and patient characteristics were well balanced between treatment arms. Fifty-seven percent had a negative PET scan following completion of R-CHOP. Median follow-up time for all patients was 48 months (range 0.03–80). At the time of analysis, 209 events had occurred. The DFS HR for enzastaurin vs. placebo was 0.92 (95% CI: 0.69, 1.22; 2-sided log-rank p=0.54). DFS at 24 and 48 months were 79% and 70% for the enzastaurin arm, and 75% and 71% for placebo, respectively. OS at 24 and 48 months was 87% and 81% for enzastaurin, and 89% and 82% for placebo; HR for enzastaurin vs. placebo was 1.04 (95% CI: 0.74, 1.47; 2-sided log-rank p=0.81). Percent of ITT population patients on therapy at 12, 24, and 36 months was 70.6%, 60.6%, and 20.1% for enzastaurin; 72.3%, 60.6%, and 22.1% for placebo. Biomarker subgroup analysis was performed and will be available at time of presentation. Treatment emergent AEs (all grades) that were possibly study drug-related and significantly different between enzastaurin and placebo included chromaturia (18.5% vs. 0.4%), QTc prolongation (10.8% vs. 3.6%), and diarrhea (10.3% vs. 2.8%). There were no significant differences in number of patients with at least 1 grade 3 or higher AE between treatment arms. No significant differences were observed in the frequency of deaths while on therapy. Conclusion Enzastaurin did not improve DFS, EFS, or OS in patients with high-risk DLBCL and CR following R-CHOP treatment. Disclosures: Crump: Roche: Honoraria; Jansen-Ortho: Honoraria; Celgene: Honoraria; Lundbeck: Honoraria; Novartis: Research Funding; Seattle Genetics: Honoraria. Off Label Use: rituximab for maintenance therapy post autolgous transplant for lymphoma. Leppä:Eli Lilly: Research Funding. Ogura:Eli Lilly: Research Funding. Rifkin:Millenium, Celgene, ONYX: Membership on an entity’s Board of Directors or advisory committees. Mackensen:Eli Lilly: Consultancy. Offner:Eli Lilly: Membership on an entity’s Board of Directors or advisory committees. Smith:Genentech, Celgene, Spectrum, Seattle Genetics, Gilead, Amgen/Micronet: Consultancy. Tobinai:Eli Lilly: Research Funding. Hahka-Kemppinen:Eli Lilly: Employment. Thornton:Eli Lilly: Employment. Shi:Eli Lilly: Employment. Lin:Eli Lilly: Employment. Kahl:Genentech: Consultancy. Savage:Eli Lilly: Consultancy.

Abstract Background:Recurrent mutations in ATM, JAK1/3 and STAT5B genes have been identified in T-cell prolymphocytic leukemia (T-PLL), a mature T cell leukemia with poor survival. However, much remains to be understood regarding the dysregulated pathways involved in the pathogenesis of this aggressive disease. Here, we integrated the analyses of whole exome sequencing (WES) and transcriptomes of a cohort of 12 T-PLL samples to gain further insights into molecular mechanisms of this malignancy. Methods: Leukemic cells were isolated from peripheral blood or bone marrow samples of T-PLL patients. Tumor DNA and RNA, and germline DNA were extracted from purified leukemic T cells and bone marrow derived stromal cells, respectively. WES (n=12) and transcriptome analysis (n=10) were performed and data analyzed with published standard methods (Robinson et al. 2010 and DePristo et al. 2011) Results: 7 paired tumor and germline DNA and 5 tumor-only DNA samples were used for WES analysis. Mutations in ATM and TET2 were detected in 4 (33%) and 1 (8%) patients, respectively. JAK3 (p.M511I, p.Q501H and p.Q503H) or STAT5B (2 p.T628S and 1 p.N642H) mutations each occurred in 3 (25%) cases and were mutually exclusive, consistent with prior reports. Importantly, we found several novel mutations in genes with regulatory roles in the NOTCH signaling pathway. Specifically, 2 somatic mutations p.A3V and p.A3S in NOTCH2 and 2 other mutations (p.S244L and p.A1414V) in NOTCH4 were identified in 4 (33%) patients. One mutation was in the EGF- like and another one in the NODP domain critical for NOTCH-mediated cellular differentiation. Two (16.7%) novel missense mutations (p.G174D and p.V836I) were found in MAML2. Three missense mutations (2 p.S583N and 1 p.R190H) occurred in MAML1. Both MAML2 and MAML1 are essential cofactors of the NOTCH signaling pathway. In addition, a somatic mutation in the NOTCH signal regulator DTX2 (p.G268D) was detected. Altogether 7 (58.3%) patients harbored mutations in genes with a regulatory role in the NOTCH pathway. Among the epigenetic modifiers, we found deletions and point mutations in KDM6B and KDM6A in 4 (30%) patients including 2 codon deletions in KDM6B (p.X751Val) and 1 missense mutation each in KDM6B (p.R1016Q) and KDM6A (p.V510G). KDM6A and KDM6B are histone H3 lysine 27 demethylases known to be involved in regulation of DNA repair and play an important role in embryonic differentiation. Transcriptome analyses of 10 T-PLL cases versus normal CD3+ T cells from 5 healthy donors revealed 706 up-regulated and 655 down-regulated genes. Consistent with prior data, TCL1A and TCL1B were significantly overexpressed (23.7 and 13.1 fold, respectively). Using Ingenuity Pathway Analysis, we found PTEN Signaling, glutamate receptor, and axonal guidance signaling to be among the top 3 upregulated pathways. The top upstream regulators implicated for the up-regulated signals were FGF, Wnt/β-catenin and TNF. The top 3 down-regulated pathways were granulocyte adhesion and diapedesis, IL-17A in psoriasis and IL-10 signaling. The top regulators for the down-regulated pathways were LPS, TNF and IFNg. Wnt/β-catenin and Human embryonic stem cell pluripotency signaling were among the top 20 up-regulated pathways. Many genes involved in the regulation of Wnt signal pathway were included in the above pathways, including Wnt ligands (Wnt9A, Wnt4), transmembrane receptors (CDH1, LRP5, FZD6, FZD7, SMO), cytoplasmic factor (AXIN2), and nuclear factors (MYC, SOX12, SOX8, SOX18, CCND1). Summary: Our study identified recurrent mutations in the NOTCH signaling pathway as well as dysregulated embryonic developmental pathway, e.g. Wnt/NOTCH as newly implicated molecular mechanisms in T-PLL pathogenesis for further functional studies. Additionally, novel (KDM6A and KDM6B) and known mutations (ATM, TET2) in chromatin regulatory genes underscore the importance of epigenetic dysregulation in the tumorigenesis of T-PLL. Disclosures Parikh: Pharmacyclics: Honoraria, Research Funding. Mustjoki:Ariad: Research Funding; Bristol-Myers Squibb: Honoraria, Research Funding; Pfizer: Honoraria, Research Funding; Novartis: Honoraria, Research Funding. Ding:Merck: Research Funding.

Abstract Introduction: Localized immunoglobulin light chain amyloidosis (LAL) is a rare disease. Systematic data regarding its presentation, management and patient outcomes are limited to small case series. Our objective was to systematically describe the Mayo clinic experience of patients with LAL. Methods: We retrospectively reviewed clinical records of 403 patients with biopsy proven localized amyloidosis seen at the Mayo Clinic between 1969-2014. Median follow-up for survival and progression were 72 months and 39 months, respectively Results: OF 5551 patients with light chain amyloidosis seen at the Mayo clinic during the study period, 403 (7%) had LAL. Median age at diagnosis was 60 years (range, 13-93) and 51% of them were male. Sites involved included: urothelial (bladder, ureter, renal pelvis), 75 (19%), larynx, 51 (13%), lung parenchyma, 42 (11%), skin, 44 (11%), synovial tissue 36 (9%), tracheobronchial, 31 (8%), gastrointestinal tract, 30 (8%), seminal vesicles, 22 (6%), eyes, 23 (6%), pharynx 22 (6%) and other 24 (6%). Typing was performed in 178 (45%) cases. A monoclonal protein was detected in 23 of 351 (7%) evaluated cases, 5 of which had different light restriction from that of LAL. Thirty one (8%) patients had a co-existent autoimmune disease. No patients progressed to systemic AL. Of 403, 109 (27%) were observed or received supportive care only and 241 (60%) underwent local removal of the amyloid deposits. Sixty-four (16%) patients required repeated interventions (median 1, range 1-4, upper decile requiring 4 interventions) for progressive disease. The most common sites requiring repeated interventions were: urothelial (33%), laryngeal (19%) and tracheobronchial (8%). Ten year overall survival (OS) and progression free survival were 79% and 61%, respectively and there was no difference according to site of involvement. Of the 70 patients that died during the follow-up period, cause of death was known for 29 and death was attributed to LAL in only 2 cases. Conclusions: In the largest series of patients with LAL reported so far we demonstrated that LAL has an excellent prognosis but can sometimes be associated with significant morbidity. Although our study was limited by incomplete typing in 55% of cases, it appears that true LAL does not "progress" to systemic amyloidosis. However, systemic amyloidosis can frequently involve organs typical involved only in LAL;, therefore a complete work-up for systemic disease should be performed in all patients with LAL. Treatment usually involves local excision for symptom palliation. In 16% of cases, repeated interventions for relapse/progression were required and as a result, follow-up is recommended, especially for cases involving the urothelial and upper respiratory tract. Disclosures Kumar: Skyline, Noxxon: Honoraria; Celgene, Millennium, Onyx, Novartis, Janssen, Sanofi: Research Funding; Celgene, Millennium, Onyx, Janssen, Noxxon, Sanofi, BMS, Skyline: Consultancy.

Background Ixazomib is the first orally administered PI studied in the clinic. The feasibility of combining ixazomib weekly and lenalidomide-dexamethasone (Rd) in the first all-oral PI- and immunomodulatory drug-containing triplet regimen was evaluated in a phase 1/2 trial of 65 pts with newly diagnosed MM. Results indicated a 90% ORR (62% ≥VGPR) using ixazomib 4 mg (recommended phase 2/3 dose), with a manageable safety profile, including 14% gr ≥3 skin/subcutaneous tissue disorders and limited (4% gr 3) peripheral neuropathy (PN) (Kumar et al, Lancet Oncol 2014). These data provided the rationale for phase 3 investigation of IRd vs placebo-Rd in pts with RRMM in this randomized, double-blind, placebo-controlled, international, multicenter study. Methods Adults with RRMM after 1-3 prior lines of therapy who were not refractory to prior lenalidomide or PI-based therapy were randomized 1:1 to receive ixazomib 4 mg or matching placebo weekly on d 1, 8, and 15, plus lenalidomide 25 mg PO on d 1-21 (dose reduced for renal impairment per local label/practice) and dexamethasone 40 mg PO on d 1, 8, 15, and 22, in 28-d cycles. Randomization was stratified by number of prior therapies (1 vs 2/3), PI exposure (naïve vs exposed), and ISS disease stage (I/II vs III). Cycles were repeated until disease progression or unacceptable toxicity. Primary endpoint was PFS as assessed by an independent review committee blinded to treatment, per IMWG criteria. Key secondary endpoints were OS and OS in high-risk pts with del(17). Sample size was determined to provide 80% power for the OS endpoint and adequate power to test PFS. Three interim analyses (IAs) and a final analysis were planned to test PFS and OS; here, we report data from the first IA, the final analysis for PFS. Results 722 pts were randomized (360 IRd; 362 Rd). Baseline characteristics were balanced between groups; overall median age was 66 yrs (30-91), 70% were PI-exposed, 88% were ISS stage I/II, 59% had received 1 prior therapy, and 77%/11%/11% were relapsed/refractory/relapsed and refractory, with 6% primary refractory. Based primarily (97%) on central laboratory evaluation, 19% had high-risk cytogenetics by FISH (del(17), t(4;14), or t(14;16)), including 10% del(17). Prior therapies included 69% bortezomib, 45% thalidomide, and 12% lenalidomide. The study met the primary endpoint at the first IA (median follow-up 14.8 vs 14.6 mos with IRd vs Rd), demonstrating a 35% improvement in PFS with IRd vs Rd (HR 0.742; p=0.012; Table). In pts with high-risk cytogenetics, the PFS HR was 0.543 with IRd vs Rd (HR 0.596 in pts with del(17)), with a median PFS similar to the overall IRd group, indicating ixazomib may overcome the negative impact of cytogenetic alterations. OS data were not yet mature. Key response data are shown in the Table. Pts received a median of 13 (1-26) vs 12 (1-25) cycles of IRd vs Rd; 55% and 52% of pts remained on treatment. With IRd vs Rd, 68% vs 61% of pts had gr ≥3 AEs (driven by thrombocytopenia), 40% vs 44% had serious AEs, 13% vs 11% discontinued all study drugs due to AEs, and 3% vs 5% died on treatment. AEs observed with IRd were consistent with reported safety profiles for the individual agents. Common gr ≥3 AEs were neutropenia (19% vs 16%), anemia (9% vs 13%), thrombocytopenia (13% vs 5%), and pneumonia (6% vs 8%). Gastrointestinal events included 42% vs 36% diarrhea (6% vs 2% gr 3), 26% vs 21% nausea (2% vs 0% gr 3), and 22% vs 11% vomiting (1% vs <1% gr 3). PN rates were 28% vs 21% (2% vs 2% gr 3), 35% vs 21% had rash events (4% vs 1% gr 3), 4% vs 6% had renal failure (2% vs 3% gr ≥3), and 4% vs 3% had heart failure (2% vs 2% gr ≥3). Conclusion At this first prespecified IA, addition of ixazomib to Rd in pts with RRMM increased median PFS to 20.6 from 14.7 mos without a substantial increase in overall toxicity, including cardiac and PN toxicity. Benefit with IRd was also noted in pts with high-risk cytogenetics, including those with del(17), in whom median PFS was similar to all IRd-treated pts indicating that ixazomib may have a favorable impact on the adverse prognosis associated with genetic mutations. If approved, this all-oral combination of IRd may become a new standard of care in this setting. Table. Key efficacy data IRd Rd HR / OR Median PFS, mos 20.6 14.7 HR 0.742; 95% CI: 0.587-0.939; p=0.012 Confirmed ORR, % 78.3 71.5 OR 1.44; p=0.035 CR 11.7 6.6 OR 1.87; p=0.019 ≥VGPR 48.1 39.0 OR 1.45; p=0.014 Median time to first response (ITT analysis), mos 1.1 1.9 Median duration of response (≥PR), mos 20.5 15.0 Disclosures Moreau: Bristol-Myers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Millennium: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen-Cilag: Honoraria, Membership on an entity's Board of Directors or advisory committees; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees. Off Label Use: Investigational proteasome inhibitor ixazomib in combination with lenalidomide and dexamethasone for patients with relapsed/refractory multiple myeloma. Masszi:Janssen-Cilag: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees; BMS: Membership on an entity's Board of Directors or advisory committees. Bahlis:Johnson & Johnson: Speakers Bureau; Johnson & Johnson: Consultancy; Amgen: Consultancy; Johnson & Johnson: Research Funding; Celgene: Consultancy, Honoraria, Research Funding, Speakers Bureau. Sandhu:Amgen: Consultancy, Honoraria; Celgene: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Novartis: Consultancy, Honoraria. Ganly:Novartis: Honoraria; Roche: Honoraria; Medipics: Equity Ownership. Baker:Janssen-Cilag New Zealand: Membership on an entity's Board of Directors or advisory committees. Stoppa:Novartis: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; Celgene: Consultancy, Honoraria. Simpson:Celgene: Honoraria; Janssen-Cilag: Honoraria; Onyx Pharmaceuticals: Research Funding; Roche: Honoraria. Gimsing:Amgen: Honoraria. Palumbo:Celgene, Millennium Pharmaceuticals, Amgen, Bristol-Myers Squibb, Genmab, Janssen-Cilag, Onyx Pharmaceuticals: Consultancy, Honoraria; Novartis, Sanofi Aventis: Honoraria. Garderet:Bristol-Myers Squibb: Consultancy. Cavo:Janssen-Cilag, Celgene, Amgen, BMS: Honoraria. Kumar:AbbVie: Research Funding; Janssen: Research Funding; Celgene: Research Funding; Sanofi: Research Funding; Onyx: Research Funding; Celgene, Millenium, Sanofi, Skyline, BMS, Onyx, Noxxon,: Other: Consultant, no compensation,; Skyline, Noxxon: Honoraria; Millenium/Takeda: Research Funding. Touzeau:AbbVie: Research Funding. Laubach:Novartis: Research Funding; Onyx: Research Funding; Celgene: Research Funding; Millennium: Research Funding. Lin:Millennium Pharmaceuticals, Inc.: Employment. Berg:Millennium Pharmaceuticals, Inc.: Employment. DiBacco:Millennium Pharmaceuticals, Inc.: Employment. Hui:Millennium Pharmaceuticals, Inc., Cambridge, MA, USA, a wholly owned subsidiary of Takeda Pharmaceutical Company Limited: Employment. Richardson:Gentium S.p.A.: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Membership on an entity's Board of Directors or advisory committees; Celgene Corporation: Membership on an entity's Board of Directors or advisory committees; Millennium Takeda: Membership on an entity's Board of Directors or advisory committees; Jazz Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees, Research Funding.

Abstract Background: High risk CLL patients treated with novel targeted therapies continue to experience disease progression (PD), and more than 50% of these PD patients evolve into Richter's syndrome (RS), (Maddocks, Jama Oncol 2015). Standard chemotherapy for large cell lymphoma has limited efficacy (median overall survival <12 months) in RS. Novel immunotherapy using a PD-1 antibody to block immune checkpoint signals to activate the cytotoxic T -cell has significant efficacy in relapsed Hodgkin lymphoma (Ansell, NEJM 2015). We conducted a phase 2 trial to test the safety and clinical efficacy of the anti-PD-1 antibody pembrolizumab in patients with relapsed/refractory CLL and relapsed low grade B non-Hodgkin lymphoma (B-NHL) (MC1485 trial). Methods: MC1485includes two arms: patients with relapsed/refractory CLL (including RS) and patients with relapsed B-NHL. The main end points of this study are safety and overall response rate. The first 6 patients enrolled in either arm were included in a designed safety interim analysis. Here we report the initial interim analysis from the CLL arm. Relapsed/refractory CLL including RS who had ECOG performance 0-2 and normal organ function were included. Patients with active autoimmune disease or interstitial lung disease were excluded. Pembrolizumab 200 mg was administered intravenously every 3 weeks until progression, excessive toxicity, or completion of 2 years of therapy. Soluble plasma PD-L1 levels were measured in these 6 patients using an established ELISA assay (Frigola, Clin Cancer Res, 2011). CD8+ T cell subsets were assessed for their functional status using an established analysis (Liu, Oncoimmunology. 2013) at baseline and after 2 cycles of therapies. Results: As of July 27th, 2015, 16 relapsed/refractory CLL patients including 5 RS patients were enrolled. The median age was 71 years (58-81). The median number of prior therapies was 3 (1-6). All CLL patients had received chemoimmunotherapy (FCR/PCR). 4 out of 5 RS patients had received anthracycline-containing chemotherapy. 5 out of 8 patients who had received prior ibrutinib therapy progressed on ibrutinib. 8 patients had 17p-/TP53 mutation. Herein, we report preliminary results from the interim analysis of CLL arm including 4 RS and 2 CLL as well as the 5th RS who had response evaluation by PET. The median cycles of therapy administered was 4 (3-7). One patient experienced grade 2 cytokine release syndrome with transient febrile neutropenia, grade 3 headache and skin rashes. These symptoms resolved with steroid therapy. One patient experienced grade 3 myalgia and was also treated with steroids. The other patients in this safety cohort tolerated pembrolizumab well. The most common drug-related adverse events were grade 1 dyspnea (33%, 2/6) and grade 1 anemia (33%, 2/6). Based on investigator assessment using the Cheson 2007 International Working Group Criteria, 4 out of 5 RS patients had responded to therapy. One patient had a complete remission after 2 cycles and remains in remission. One patient had almost complete PET response after two cycles and is classified as PR as her bone marrow have not been re-evaluated yet. Two patients had notable responses with nodal and skin lymphoma improvements before they showed potential evidence of progressive diseases. The remaining 1 RS and 2 CLL had stable disease and continued on therapy at the last follow-up. Soluble PD-L1 levels (sPD-L1, n=6) were measured at baseline and after 2 cycles of therapies. 3 RS patients who had responded to therapy had decreased or stable sPD-L1 levels. The 4th RS and two CLL had increased sPD-L1 levels and had not demonstrated clinical response. CD8 T-cell subset analyses performed blindly (n=4) showed increased CD8 T cell function in one of the 4 patients tested. This patient who demonstrated CD8 T cell functional enhancement is the only patient in the 4 tested patients who had notable response to pembrolizumab. Conclusion: Pembrolizumab is tolerated in relapsed CLL and RS patients. Early efficacy observed in heavily pretreated RS patients including patients progressed on both anthracycline-based treatment and ibrutinib indicate PD-1 inhibition is a promising novel approach in patients with RS. Our CD8 T cell subset analysis may be used as a biomarker assay to predict clinical response in the era of novel immunotherapy. This trial and further correlative analysis is ongoing and will be presented at the ASH meeting. Disclosures Ding: Merek: Research Funding. Shanafelt:Cephalon: Research Funding; Pharmactckucs: Research Funding; Janssen: Research Funding; Hospira: Research Funding; Polyphenon E Int'l: Research Funding; Celgene: Research Funding; Glaxo-Smith_Kline: Research Funding; Genentech: Research Funding. Kay:Tolero Pharma: Research Funding; Hospira: Research Funding; Pharmacyclics: Research Funding; Genentech: Research Funding; Celgene Corporation: Membership on an entity's Board of Directors or advisory committees, Research Funding; Gilead: Membership on an entity's Board of Directors or advisory committees, Research Funding. Ansell:Bristol-Myers Squibb: Research Funding; Celldex: Research Funding.

Abstract Background: Adult T-cell acute lymphoblastic leukemia / lymphoma (T-ALL) is an rare and aggressive hematological malignancy with overall survival (OS) according to the UKALL XII/E2993 of 48% at 5 years (Marks et al, Blood 2009). Over the last decade, the incorporation of L-asparaginase, dose intensification (similar to pediatric protocols), availability of newer agents such as clofarabine (Dec 2004) and nelarabine (Oct 2005) have been shown to improve outcomes. We carried out this study to see if the above mentioned changes in treatment have translated to an OS benefit. Methods: After due IRB approval, adults diagnosed with T-ALL from 1990-2014 at Mayo Clinic were identified. All clinical and pathologic data was retrospectively reviewed Comparative analysis was performed based on year of diagnosis before and after 2005 (Group 1, diagnosis prior to 2005, and Group 2, diagnosis post 2005). Survival was estimated using the Kaplan-Meier Method and log-rank test. Chi-square test was used to compare variables. Results: A. Patient Characteristics: Between 1990 and 2014, a total of 92 consecutive patients (pts) with T-ALL were identified. Median age at diagnosis was 33 years (range; 18-88 years) with 72% males. Distribution of pts by year of diagnosis was as follows: Group 1(n= 47) (51%), and Group 2 (n=45) (49%). Median overall survival was 97.2 months. Median follow up for Group 1 was 50 months, during which time 23 (39%) deaths were documented, and 22.8 months (0.9 - 115.4) for Group 2 at which time19 deaths (42%) were documented (p= 0.04). Pts in Group 2 were older than Group1 (median age 41 vs 27 years (p= 0.004). Apart from age, the two groups were similar in other characteristics (Table 1). B. Therapy received by patient groups: We observed a high use of L-asparaginase containing regimens in Group 1 vs Group 2 [35(74%) pts vs 19 (42%), p=0.0013]. In contrast there was an increase in use of Hyper-CVAD in Group 2; 23(51%) vs. 3 (6%) (p<0.0001). There was no difference in the use of intensive pediatric protocols (p=0.11). There was a trend of increased use of nelarabine in Group 2, however clofarabine usage was not different (p=0.09, and p=0.6 respectively) (Table1). Allogenic stem cell transplant was offered more in Group 2 compared to Group 1, 16 (36%) patients vs. 10 (21%) patients (p=0.0009). In contrast, 7 (19%) patients underwent autologous transplantation in group 1 vs. none in group 2 (p=0.0009). C. Overall outcome by patient groups: We did not observe any difference in CR, or relapse rates among the two groups. The median OS and time to relapse were also not statistically different among Group 1 and 2 [102.6 vs 61.8 months Figure A, and 7.1 vs 14.1 months respectively]. Furthermore, age adjusted survival analysis was also not statistically significant. Conclusion: In this large cohort of adult T-ALL patients, in spite of significant advances in treatment strategies over the last two decades, we observed no difference in overall and relapse free survival prior to and after 2005. Figure 1. Figure 1. Figure 2. Figure 2. Disclosures Al-Kali: Celgene: Research Funding. Thompson:Kite Pharma: Research Funding. Witzig:Spectrum: Research Funding; Novartis: Research Funding; Celgene: Research Funding; Amgen: Honoraria; Valeant Pharma: Equity Ownership.

Abstract Background Bendamustine/rituximab (BR) and dexamethasone/rituximab/cyclophosphamide (DRC) combination therapy are acceptable options for the treatment of WM, both in the frontline or salvage setting. Prospective data, however, are only available in treatment-naïve (TN) WM patients, and no direct comparison between BR and DRC has been reported. We compared outcomes of BR and DRC in relapsed/refractory (R/R) and TN WM patients seen at a single institution. Methods Records of WM patients seen consecutively at Mayo Clinic from 01/2007 to 12/2014 were reviewed. The MYD88L265P status, as assessed by AS-PCR, was recorded when available. The data obtained from symptomatic patients treated with DRC or BR were analyzed. The time-to-event analyses were performed from DRC or BR therapy using the Kaplan-Meier method. We used the Consensus criteria (6th International Workshop) for response assessment. Results Of 160 WM patients, 60 patients received BR (73% in R/R setting) and 100 patients received DRC (50% in R/R setting). In the R/R population, BR was the 2nd line (range 2-11) therapy in 47% of patients, while DRC was 2nd line (range 2-8) in 58% of patients. Rituximab monotherapy was the only prior line of therapy in 8 (20%) patients in the BR group and 20 (40%) in the DRC group (p=0.66). Baseline characteristics were similar in patients treated with BR or DRC (Table 1). Six patients received both BR and DRC during their disease course and overlapped between the 2 cohorts. Among the previous untreated patients, the median IgM levels decreased from 3,785 mg/dL to 724 mg/dL (p=0.0001) at best response with BR, while it decreased from 4,130 mg/dL to 1,250 mg/dL (p=0.001) with DRC. The median time to best response was 6.1 (1-25) months in the BR group and 11 (0.5-47) months in the DRC group (p=0.13). For patients treated with BR, the overall response rate (ORR) was 93% [VGPR 29% (n=4), PR 57% (n=8), MR 7% (n=1)]. One patient (7%) had progressive disease. For patients treated with DRC, ORR was 96% [VGPR 17% (n=8), PR 70% (n=32), MR 9% (n=4)]. One patient (4%) achieved SD. Median follow up in the BR and DRC groups were similar (30 months). The 2-year progression-free survival (PFS) was 88% and 61% in the BR and DRC groups, respectively (p=0.08). The 2-year time-to-next therapy (TTNT) was 88% and 76% in the BR and DRC groups, respectively (p=0.35). Median PFS, TTNT and disease specific survival (DSS) were not reached with either regimen. In the R/R setting, the median IgM levels decreased from 3,880 mg/dL to 659 mg/dL (p=0.0001) at best response with BR, and from 3,870 mg/dL to 1,846 mg/dL (p=0.001) with DRC. The median time to best response was similar [7 (1-39) months with BR and 7 (0.5-28) months with DRC (p=0.77)]. For patients treated with BR, ORR was 95% [CR 3% (n=1), VGPR 38% (n=14), PR 41% (n=15), MR 13% (n=5)]. Two patients (5%) had progressive disease. With DRC, the ORR was 87% [VGPR 4% (n=2), PR 64% (n=30), MR 19% (n=9)]. Four patients (9%) achieved SD and 2 patients (4%) had progressive disease. Median follow up from BR was 32 months and 51 months from DRC (p=0.24). The 2-year PFS was 66% and 53% in the BR and DRC groups, respectively (p=0.08). The 2-year TTNT was 75% and 68% in the BR and DRC groups, respectively (p=0.24). The median DSS in the BR group was 69 months (95% CI: 65-69) and NR (95% CI: NR-NR) in the DRC group (p=0.57). The proportion of patients with R/R disease was significantly higher in the BR cohort (Table 1). In a bivariate analysis of the entire cohort for PFS, incorporating the setting (TN vs. RR) and the regimen involved (BR vs. DRC), the latter emerged as a significant factor (hazard ratio 0.52, p=0.019) in favor of BR. Time-to-event outcomes and response rates were similar in the MYD88L265P and MYD88WT patients. Grade ≥ 3 adverse events were neutropenia (12%), infections (7%) and nausea/vomiting (2%) with BR, and neutropenia (20%), thrombocytopenia (7%) and infections (3%) with DRC. Conclusions Although both DRC and BR regimens show activity and comparable toxicities, BR regimen shows a trend for superior PFS in WM patients, both in the TN and R/R setting. No difference was seen in TTNT. MYD88 L265P mutation status does not appear to impact activity of BR or DRC. Randomized controlled trial(s) are needed to confirm our findings. Disclosures Ailawadhi: Pharmacyclics: Consultancy; Novartis: Consultancy; Amgen Inc: Consultancy; Takeda Oncology: Consultancy. Ansell:BMS, Seattle Genetics, Merck, Celldex and Affimed: Research Funding. Reeder:Millennium: Research Funding; BMS: Research Funding; Novartis: Research Funding; Celgene: Research Funding. Dispenzieri:Jannsen: Research Funding; Takeda: Membership on an entity's Board of Directors or advisory committees, Research Funding; pfizer: Research Funding; Prothena: Membership on an entity's Board of Directors or advisory committees; Celgene: Research Funding; Alnylam: Research Funding; GSK: Membership on an entity's Board of Directors or advisory committees. Kumar:Sanofi: Consultancy, Research Funding; Janssen: Consultancy, Research Funding; AbbVie: Research Funding; Array BioPharma: Consultancy, Research Funding; BMS: Consultancy; Kesios: Consultancy; Glycomimetics: Consultancy; Skyline: Honoraria, Membership on an entity's Board of Directors or advisory committees; Noxxon Pharma: Consultancy, Research Funding; Millennium: Consultancy, Research Funding; Onyx: Consultancy, Research Funding; Celgene: Consultancy, Research Funding. Kapoor:Celgene: Research Funding; Takeda: Research Funding; Amgen: Research Funding.