Leis, José F.

Abstract Background Severe cytopenias in CLL are typically associated with bone marrow failure due to massive infiltration of the bone marrow by leukemic cells and negatively impact patient morbidity/mortality. Although near complete marrow replacement by CLL is typically observed in patients whose degree of cytopenia meet criteria for advanced Rai stage disease (Hg<11g/dL; platelet <100 x10^9/L), profound variability in the degree of cytopenia and the extent of marrow infiltration exists, and the relationship between these dimensions is not well characterized. Methods We used the Mayo Clinic CLL database to identify all previously untreated CLL/SLL patients who underwent bone marrow biopsies. CLL patients known to have autoimmune-based cytopenias were excluded from this study. Hemoglobin, platelets, absolute neutrophil count (ANC), absolute lymphocyte count (ALC), and absolute monocyte (AMC) at the time of bone marrow biopsy were collected. Characteristics from bone marrow biopsy including marrow cellularity, % CLL involvement, CLL leukemic index (calculated as % cellularity times % CLL), and non-CLL leukemic index (calculated as % cellularity times (1-% CLL)) were also collected. Bone marrow cellularity and % CLL involvement were recorded in the Mayo Clinic CLL database based on clinical estimates made by Mayo hematopathologists. Clinical characteristics and CLL prognostic factors (e.g., Rai stage, CLL FISH, IGHV, ZAP-70, CD38 and CD49d) were also obtained from the database. Age- and sex-adjusted Pearson correlations between the bone marrow measurements and hemoglobin and platelet levels were computed, and scatterplots were created. Results A total of 695 untreated CLL patients diagnosed between 1972 and 2015 who had a CBC test at the time of bone marrow biopsy performed at Mayo Clinic were identified. Median age at diagnosis was 61 years, and 487 (70%) patients were men. Mean time from CLL diagnosis to bone marrow biopsy was 2.2 years. At the time bone marrow biopsy was performed, 20% of patients had advanced stage disease (Rai III/IV) disease, while 44% and 36% had intermediate (Rai I/II) and early stage (Rai 0), respectively. With respect to prognostic parameters, 53% had unmutated IGHV and 20% had high risk CLL FISH (11q- and 17p-). The distribution of other prognostic factors included 43% CD49d+, 35% CD38+, and 42% ZAP-70+ CLL diseases. Median peripheral blood counts were: hemoglobin 13g/dL, platelet 167,000/mL, ALC 26,600/mL, ANC 4100/mL, AMC 700/mL. The median bone marrow cellularity and percent CLL involvement were 70% and 70%, respectively. The median CLL leukemic index was 42%, and median non-CLL leukemic index was 21%. Pearson correlation analysis of bone marrow measurements with peripheral blood hemoglobin found the strongest correlation with the CLL leukemic index (r= -0.49, p<0.001) (Figure), followed by the % marrow CLL involvement (r= -0.45, p<0.001), cellularity (r= -0.40, p<0.001), and non-CLL leukemic index (r= 0.37, p<0.001). Pearson correlation analysis of the bone marrow measurements with platelet count also found the strongest correlation with the CLL leukemic index (r= -0.39, p<0.001), followed by % marrow CLL involvement (r= -0.38, p<0.001), non-CLL leukemic index (r= 0.35, p<0.001), and cellularity (r= -0.28, p<0.001). The peripheral blood ANC levels did not correlate with the four bone marrow measurements. Age- and sex-adjusted Pearson correlations between the bone marrow measurements and hemoglobin and platelet levels were similar to the above unadjusted results. Conclusion To our knowledge, this is the first study to examine the relationship between peripheral blood counts and the extent of bone marrow infiltration in patients with CLL. Although the bone marrow leukemic index had the strongest correlation with peripheral blood Hg and platelet counts, the correlation was modest with an r value of -0.49. These findings suggest that the extent of infiltration of the bone marrow by CLL cells only partially explains of the anemia and thrombocytopenia observed in CLL, indicating other biologic interactions between CLL B-cells and hematopoietic cells contribute to anemia and thrombocytopenia in these patients. More research is needed to determine the nature of these interactions. Disclosures Ding: Merek: Research Funding. Kay:Genentech: Research Funding; Pharmacyclics: Research Funding; Hospira: Research Funding; Celgene: 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; Tolero Pharm: Research Funding. Shanafelt:genentech: Research Funding; Glaxo-Smith-knine: Research Funding; Celgene: Research Funding; Cephalon: Research Funding; Pharmacyclics: Research Funding; Janssen: Research Funding; Hospira: Research Funding; Polyphenon E Int'l: Research Funding.

Abstract Abstract 1268 Poster Board I-290 Purpose There are reports of an increased risk of skin cancers in patients with B-Chronic Lymphocytic Leukemia (CLL). These skin cancers include basal cell and squamous cell carcinoma. This analysis was performed to more completely define the prevalence of skin cancers in patients in the Mayo Clinic Rochester CLL database and to look for contributing factors. Methods The Mayo Clinic Rochester CLL Database includes all patients with a diagnosis of CLL since January 1995 seen in the Division of Hematology and who have signed institutional review board approved consents for research. For this study, 2240 patients were analyzed to compare differences in characteristics between CLL patients with and without skin cancer. Chi-square statistics were used to compare qualitative variables (age categories, gender, referral status, ALC categories, CD38, ZAP-70, IgVH gene mutation status, FISH categories, Rai stage), and t-tests were used for quantitative variables (age at diagnosis, ALC values). Overall survival (OS) and time to first treatment (TFT) analyses were performed with results being displayed using Kaplan-Meier curves and p-values calculated using a log-rank test. Prevalence of melanoma among CLL patients was compared to the age-adjusted prevalence of melanoma in individuals in the Iowa SEER registry. Results Median follow-up for the 2240 patients diagnosed between 1/1/1995 and 8/11/2009 was 4.6 years. In aggregate, 293 (13.1%) patients were found to have non-melanoma skin cancer (squamous cell carcinoma or basal cell carcinoma) cancer. The diagnosis of non-melanoma skin cancer occurred before the CLL diagnosis in 39% and at or after the diagnosis of CLL in 61%. There were 57 (2.5%) cases of melanoma in association with CLL. The diagnosis of melanoma occurred before the CLL diagnosis in 38% and at or after the diagnosis of CLL in 62%.The prevalence of non-melanoma skin cancer and melanoma skin cancer were both higher in non-referred (geographically regional) CLL patients than referred CLL patients (16.6% vs. 11.4%, p<0.001 for non melanoma; 2.0% vs. 3.6%, p=0.03 for melanoma). The prevalence of melanoma in CLL patients was higher than that of age-adjusted prevalence for individuals in the Iowa SEER registry (2.5% vs. 0.03%; p<0.001). We next evaluated the relationship between CLL patients with skin cancer and demographic characteristics, prognostic parameters, and CLL related treatment. The risk of non-melanoma skin cancer in CLL was found to be associated with age (median age at diagnosis with skin cancer 67.6 vs. without skin cancer 63.3, p<0.001) and with sex (males 15.1% vs females 8.9%, p <0.001). There was no statistical significant difference in frequency of non-melanoma skin cancer associated with absolute lymphocyte count (ALC), Rai stage, CD 38, Zap 70, IgVH gene mutation status, FISH, or treatment history. The risk of melanoma in CLL was found to be associated with age at diagnosis (median age with melanoma 69.9 vs. without melanoma 63.8, p=0.002) and CD38 (positive 1.3% vs negative 3.1%, p=0.03). There was no statistically significant difference associated with gender, ALC, Rai stage, Zap 70, IgVH gene mutation status, FISH, or treatment history. Since the presence of skin cancer could be a marker of immune dysregulation we hypothesized skin cancer may be associated with clinical outcome of CLL. Accordingly, we evaluated the relationship between non-melanoma skin cancer and melanoma skin cancer and TFT and OS. Contrary to our hypothesis, TFT (median 6.0 years vs. 4.9; p=0.04) and OS (median 10.8 years vs. 9.7; p=0.02) of patients with non-melanoma skin cancer were both longer than those without non-melanoma skin cancer. No differences in TFT (p=0.06) or OS (p=0.66) were observed among patients with melanoma compared to those without melanoma. Conclusions We find in our cohort of CLL patients a higher prevalence of melanoma than the general population. Risk of melanoma and non-melanoma skin cancer among patients with CLL does not appear to be related to CLL characteristics, with the exception of CD 38, or CLL outcome. The diagnosis of melanoma and non-melanoma skin cancer in patients with CLL does not appear to be a risk factor for either CLL specific outcomes (TFT) or shorter survival. Disclosures Kay: Biogenc-Idec, Celgene, Genentech, genmab: Membership on an entity's Board of Directors or advisory committees; Genentech, Celgene, Hospira, Polyphenon Pharma, Sanofi-Aventis: Research Funding. Zent:Genentech, Bayer, Genzyme, Novartis: Research Funding. Shanafelt:Genentech: Research Funding; Hospira: Membership on an entity's Board of Directors or advisory committees, Research Funding; Polyphenon E International: Research Funding; Celgene: Research Funding; Cephalon: Research Funding; Bayer Health Care Pharmaceuticals: Research Funding.

Abstract Abstract 4527 Introduction: The prognosis for pts with intermediate or high risk AML remains dismal, with relapse rates typically in the 60–80% range after treatment with chemotherapy alone. While allo-SCT can decrease the risk of relapse to 10–20%, widespread use of this modality is limited by relatively high rates of non-relapse mortality (NRM), often due to severe acute and/or chronic GVHD. Attenuation of severe GVHD, without a concomitant increase in relapse or NRM, should improve outcomes and result in cure of a larger fraction of AML pts. We therefore investigated the use of in-vivo T-cell depletion with r-ATG in pts with intermediate- or high-risk AML but without active leukemia at the time of allo-SCT. Patients and Methods: Pts (n = 43) were included in this retrospective analysis if they were between 18 and 65 years of age and had no evidence of active AML at the time of allo-SCT (see Table). All pts had 1 or more high-risk features: 1) adverse or intermediate risk cytogenetics (without NPM1 mutation if cytogenetically normal); 2) therapy-related or secondary AML; 3) high WBC count at diagnosis; 4) failure to achieve CR after 1 cycle of induction; or 5) not in CR1 at allo-SCT. Among the 43 pts, 10 received grafts from related donors, 14 from 10/10 matched unrelated donors (URDs), and 19 from mismatched URDs (9/10, n = 11; 8/10, n = 8). All pts received r-ATG according to institutional standard operating policy, with doses ranging from 2.5 – 10 mg/kg depending on donor type and degree of mismatch. All transplants were performed using PBSC. Additional GVHD prophylaxis included tacrolimus plus either methotrexate or mycophenolate mofetil. Results: The median age was 47 (range 20 – 65), and median follow-up for surviving pts is 12 (range 1 – 66) months. As of 8/5/11, 39 pts were alive, and 4 had died from multiorgan failure (n = 1), relapse (n = 1), GVHD (n = 1), and veno-occlusive disease (n = 1). The 2-year estimate of PFS is 84.7% (Fig. 1). The 2-year cumulative incidence of relapse is 6.8% (2 pts, days 97 and 147), and of non-relapse mortality 9.4%. Three pts developed severe (grades III-IV) acute GVHD by day 100 (cumulative incidence 4.6% at day 100) with no additional cases of severe acute GVHD beyond day 100. To date, 4 pts have developed moderate/severe chronic GVHD (cumulative incidence 16.8% at 2 yrs), with one death at day 344 related to complications of acute and chronic GVHD. CMV reactivation occurred in 29 pts (56%), with no deaths related to CMV. Three pts have reactivated EBV, with one case of PTLD (all treated with Rituximab). Conclusions: In this retrospective analysis of single center data, the inclusion of r-ATG in the GVHD prophylactic strategy appeared to significantly attenuate the incidence and severity of both acute and chronic GVHD. Although follow-up is relatively early, the incidence of relapse and NRM does not appear to be increased compared to contemporaneous pts treated without ATG. Given that almost half of the pts received grafts from mismatched URDs, this abrogation in risk of GVHD is significant and clinically relevant. While randomized studies are needed, these data suggest that in-vivo T-cell depletion with r-ATG ameliorates severe GVHD, without increasing relapse or non-relapse mortality, in AML pts without overt leukemia at the time of allo-SCT. Using this strategy, cure rates of 70 – 80% may be realistic and attainable for younger (</= age 65) AML patients who achieve a leukemia-free state and who have a reasonably matched related or unrelated donor. Disclosures: Reeder: Celgene: Research Funding; Millennium Pharmaceuticals Inc.: Research Funding; Novartis: Research Funding.

Abstract Abstract 2443 Background: There is strong and consistent evidence that a genetic component contributes to the etiology of chronic lymphocytic leukemia (CLL). A recent genome-wide association (GWA) study of CLL identified genetic variants located on chromosomes 2q13, 2q37.1, 6p25, 11q24, 15q23, and 19q13 that increased the risk of CLL within a European population. We replicated 5 of these 6 loci in an independent sample of CLL cases and controls from the United States. We now investigate whether these loci also influences MBL, a reported precursor condition of CLL. In addition, a follow-up analysis of the initial GWA study identified four more CLL-susceptibility loci on 2q37.3, 8q24.21, 15q21.3, and 16q24.1. Herein, we also evaluate the association of these four loci with risk of CLL. Methods: Peripheral blood samples were obtained from three ongoing studies: the Genetic Epidemiology CLL (GEC) Consortium, the Mayo Clinic non-Hodgkin lymphoma (NHL)/ CLL study, and the Mayo Clinic Biobank. We implemented rigorous genotyping quality-control measures, and successfully genotyped a total of 407 CLL patients, 965 controls, and 60 MBLs from these studies. Within each locus, the previously reported single nucleotide variants (SNPs) or variants in high linkage disequilibrium (LD) with the previously reported SNPs were evaluated with risk of MBL or CLL. Tests for association was done using the Cochran-Armitage trend test, and unconditional logistic regression was used to estimate odds ratios (ORs) and corresponding 95% confidence intervals (CIs) for CLL or MBL risk Results: In our evaluation of the six initially reported CLL-susceptibility loci (2q13, 2q37.1, 6p25, 11q24, 15q23, and 19q13) with MBL risk, we found three of the six had suggestive associations (p-value < 0.20) with ORs comparable to and in the same direction as those observed from CLL risk. Our strongest finding was with rs13397985 at locus 2q37.1 (OR= 1.56; 95% CI: 1.05, 2.31; p-trend = 0.041), followed by rs17483466 at locus 2q13 (OR= 1.49; 95% CI: 0.99, 2.24; p-trend = 0.074). As expected given our previously reported findings with CLL risk, the association between rs11083846 on chromosome 19q13 and MBL risk was not significant (p-trend = 0.70). Of the four recently reported CLL-susceptibility loci SNPs located on 2q37.3, 8q24.21, 15q21.3, and 16q24.1, we found all to be associated with CLL risk but one. Specifically, the strongest association was seen for locus 8q24.21 (best tagged SNP rs1021955; OR = 1.37; 95% CI: 1.10, 1.70; p-trend = 0.005), followed by locus 16q24.1 (best tagged SNP rs305065; OR= 0.77; 95% CI: 0.61, 0.97; p-trend = 0.024). However, we found no associations for locus 15q21.3 for the previously reported SNP nor for any SNPs in LD with the previously reported SNP. Conclusions: Our MBL results provide additional robust genetic evidence that MBL is a precursor to CLL and that it shares similar underlying genetic predisposition. Also our results confirm three of the four recently reported CLL-susceptibility loci and further support the role of a genetic basis in the etiology of CLL. More research is needed to elucidate the potential manner in which these genetic loci function in CLL or MBL. Disclosures: No relevant conflicts of interest to declare.

Abstract Abstract 4610 Introduction Infections are a major cause of morbidity and mortality in patients with chronic lymphocytic leukemia (CLL). Up to 50% of CLL patients develop infectious complications, and 30–50% of all deaths in CLL patients are attributed to infections. Despite these data, the available research on infectious complications in CLL is primarily limited to patients participating in clinical trials of chemotherapy, obscuring the distinction between the risk of infection due to the disease’s natural history relative to the risk associated with therapy related immune suppression. METHODS: The Mayo Clinic Rochester (MCR), a tertiary referral center in rural southeastern Minnesota, is also the primary hematology center for southeastern Minnesota, northern Iowa, and western Wisconsin. There are no metropolitan areas or hematology specialty centers within a ∼50 mile radius. To explore the natural history of infection in a community-based cohort of CLL patients, we used the Mayo Clinic CLL database to identify all patients with newly diagnosed CLL who resided within 50 miles of MCR and diagnosed between January, 1999 and December, 2009. The comparison cohort consisted of 689 adult patients who also resided within 50 miles of MCR who were seen for a general medical examination between September, 2002 and December, 2009 and who were enrolled as controls in a case-control study of non-Hodgkin lymphoma. All hospitalizations at MCR among both cohorts were audited to document hospitalization with infection and cross-referenced with the Mayo Clinic infection database, which includes all culture results obtained from hospitalized MCR patients. Serologies and viral assays were also reviewed. Patients whose cultures were negative but who were given a clinical diagnosis of infection (e.g. pneumonia) and who were treated with a full course of antibiotic therapy were considered to have a culture negative infection. RESULTS: In May 2010, there were 2022 CLL patients in the Mayo Clinic CLL Database diagnosed between 1999 and 2009. Of these, 174 (9%) were local CLL patients residing within 50 miles of MCR. Median age at diagnosis for these non-referred CLL patients was 69 years (range 27–97). Most had early stage disease (60% stage 0; 32% stage I-II). On prognostic evaluation, 121 (75%) patients were CD38 negative, 66 (61%) ZAP-70 negative, 47 (50%) IGHV mutated, and 56 (62%) had either no abnormality or 13q14- as a sole abnormality on FISH analysis. 64 (37%) patients progressed to require treatment for CLL during follow-up. After median follow-up of 4.0 years (range 0–11), 32 (18.4%) CLL patients were hospitalized with infection at least once as compared to 20/689 (2.9%) individuals in the control cohort (odds ratio=7.5; p<0.0001) Figure 1A. Even prior to receiving treatment for CLL, the rate of hospitalization for infection remained higher than the control cohort (p=0.002; Figure 1B). The 32 CLL patients hospitalized with infection were admitted with infection a total of 89 times (median 1 hospitalization for infection per patient). A specific infectious organism was identified by cultures or serologies in 60 (63%) of the 89 infections in CLL cases and 10/27 (37%) infections among controls. Hospitalization for an opportunistic infection (e.g. cytomegalovirus, cryptococcus, filamentous fungi, mycobacteria, Pneumocystis) occurred in 5/174 (3%) CLL patients during follow-up compared to 0/689 controls (p<0.001). Finally, we performed a pooled multivariable analysis of all patients (n=863) to identify factors (age, sex, CLL diagnosis, CLL treatment) associated with infection risk. Most factors were independently associated with hospitalization for infection [Age (per year, OR=1.03, p=0.02), sex (male, OR=4.0, p<0.001), diagnosis of CLL (OR=2.1, p=0.09), and treatment for CLL (OR=5.9, p<0.001)]. In univariate analysis of CLL patients [sex (OR=4.2, p=0.01), higher Rai stage (p=0.046), unfavorable (del 17p13; del 11q23) FISH [OR=4.6, p=0.02] and unmutated IGHV [OR=2.8, p=0.07]) were associated with risk of infection. CONCLUSIONS: In this cohort study, patients with newly diagnosed CLL had a 7.5-fold risk of hospitalization for infection relative to the control cohort. After 4 year follow-up, ∼1 in 5 CLL patients required hospitalization for infection. Although CLL treatment was a substantial risk factor for infection, the risk of infection among untreated patients remained higher than controls. Disclosures: Kay: Biothera: Research Funding; Clegene: Research Funding; Cephalon: Research Funding; Genentech: Research Funding; Glaxo Smith Kline: Research Funding; Hospira: Research Funding; Novartis: Research Funding; Supergen: Research Funding; Calistoga: Membership on an entity’s Board of Directors or advisory committees; Celgene: Membership on an entity’s Board of Directors or advisory committees; Emergent Biosolutions (Formerly Trubion): Membership on an entity’s Board of Directors or advisory committees. Zent:GlaxoSmithKline: Research Funding; Genentech: Research Funding; Genzyme: Research Funding.

Abstract Background Although its prevalence is not well defined, transformation to Hodgkin lymphoma (HL) is a rare but well recognized complication in patients with CLL. Prior studies have reported a median survival of 0.8-1.7 years in these patients. Prior therapy of CLL, especially with purine analogs, has been shown to have adverse impact on survival after development of HL. We used the Mayo Clinic CLL database to describe outcomes of CLL patients seen at our institution who developed HL. Methods The Mayo Clinic CLL database includes all consenting patients with a pathologic diagnosis of CLL. Patients who developed biopsy-proven HL were included in this analysis. For patients referred from an outside institution, pathology review at Mayo Clinic was mandatory to be included. Clinical characteristics, therapy and overall survival (OS) were analyzed for all HL patients. Results Among 3124 CLL patients seen at Mayo Clinic from 1/1995 to 7/2011, 26 developed HL. In a nested cohort of 1644 patients who were seen within 12 months of CLL diagnosis and followed prospectively, the prevalence of HL was 0.05%/year (10 year risk=0.5%). All 26 patients had classical HL. The median duration between CLL diagnosis and development of HL was 6.2 years (range, 0-24.5 years). The median age at diagnosis of HL was 68 years (range, 45-88 years) and 21 (81%) were male. At the time of HL diagnosis, the median WBC count was 7.8 x 109/L (range, 1.3-87.3), median hemoglobin was 11 gm/dL (range, 7.2-13), median platelet count was 220x109/L (range, 53-627), median serum lactate dehydrogenase was 249 U/L (range, 133-658), and median serum albumin was 3.4 gm/dL (range, 2.6-4.2). According to the Ann Arbor staging system for HL, 10 (38%) were Stage II, 2 (8%) were Stage III, 11 (42%) were Stage IV, and undetermined in 3 (12%) patients. Sixteen patients (61%) received HL therapy with doxorubicin, bleomycin, vinblastine and dacarbazine (ABVD), seven (27%) received other chemotherapy, and treatment was unknown in 3 (12%) patients. No patient underwent stem cell transplantation as therapy for HL. After a median follow-up of 8.7 years from CLL diagnosis date, 16 (61%) patients have died. The median OS from date of HL diagnosis was 3.9 years (95% CI, 1.0 – 5.0 years). The International Prognostic score (IPS) for HL, originally proposed by Hasenclever in 1998, identified seven prognostic factors: serum albumin <4 gm/dL, hemoglobin <10.5 gm/dL, male sex, age >45 years, stage IV disease, WBC≥15 x 109/L, and lymphocytopenia in patients with newly diagnosed HL. When we applied these prognostic parameters (available in 22/26 patients, 85% in our cohort), the IPS score predicted median survival as follows: score of ≤2 (18% of the patients), median survival not reached; score of 3 (23% of the patients), 6.2 years; score of 4 (36% of the patients), 2.4 years; and score ≥5 (23% of the patients), 0.3 years (p-value=0.005, Figure 1). In contrast, the Richter syndrome prognostic score developed for CLL patients who transform to diffuse large B-cell lymphoma failed to predict survival in these patients (Tsimberidou, JCO, 2006). Of the 26 patients with HL, 16 (61%) had received therapy for their CLL prior to developing HL, including 12 (46%) who had received more than one line of therapy. Purine analogs had been administered for treatment of CLL prior to development of HL in 13/26 (50%) patients. The median survival of HL patients who had previously received CLL therapy was significantly worse compared to those who were untreated for CLL (2.8 years vs. 7.6 years, p-value=0.02). There was a trend toward shorter survival for HL patients who had received previous purine analog therapy for CLL compared to those who received alternate therapies (1.8 years vs. 5 years, p-value: p-value=0.07). Of the 9 HL biopsy samples in which Epstein Barr virus (EBV) in-situ hybridization studies were performed, EBV was detected in 6 (67%) patients. No association was observed between prior purine analog therapy and EBV status (p-value=1.0). There was no difference in survival according to the EBV status of HL (p-value=0.33). Conclusion The 10 year incidence of transformation to Hodgkin transformation among patients with newly diagnosed CLL is 0.5% (∼1/200 CLL patients). In this single-institution analysis, median survival of CLL patients who developed Hodgkin transformation of CLL was approximately 4 years after HL diagnosis. The IPS accurately predicted survival in our cohort of HL patients. Disclosures: Zent: Novartis: Research Funding; GlaxSmithKline: Research Funding; Biothera: Research Funding; Genzyme: Research Funding; Genentech : Research Funding. Shanafelt:Glaxo-Smith-Kline: Research Funding; Cephalon: Research Funding; Hospira: Research Funding; Celgene: Research Funding; Polyphenon E International: Research Funding; Genentech: Research Funding.

Abstract Abstract 2850 Myelofibrosis (MF), both primary myelofibrosis (PMF) and post essential thrombocytosis/polycythemia vera myelofibrosis (post ET/PV-MF), are chronic myeloproliferative neoplasms characterized by a progressive clinical course that leads to shortened survival. The heterogeneous nature of MF lends itself to a variable clinical course that commonly includes hepatosplenomegaly, constitutional symptoms, and progressive cytopenias. Medical therapy for myelofibrosis has been effective in palliation of common symptoms related to anemia, splenomegaly but allogeneic stem cell transplantation (ASCT) remains the only potentially curative therapeutic modality. The timing of ASCT, choice of conditioning regimen, patient selection and the impact of co-morbidities are critical to optimal use of this modality. We have retrospectively analyzed our experience for patients undergoing ASCT for primary and post ET/PV myelofibrosis at Mayo Clinic across all 3 sites: Scottsdale Arizona; Rochester, Minnesota; and Jacksonville, Florida. Methods: We conducted a retrospective review of all patients from 1992 to 2012 with PMF or post ET/PV-MF who underwent an ASCT at Mayo Clinic. This retrospective review included a waiver of informed consent and was approved by the Mayo Clinic Institutional Review Board. Patients that transformed to the MPN blast phase and individuals who underwent a second transplant for either relapse or graft failure were also included. Overall survival was estimated using Kaplan-Meier. Associations between prognostic factors and overall survival were assessed using Cox regression. Results: Baseline Patient Characteristics: Forty-eight patients (29 male) with a median age of 57 yrs (range 31–73) underwent ASCT. DIPSS-plus risk score was low in 2, intermediate 1 in 2, intermediate 2 in 9 and high in 35 patients. Disease type was PMF in 24, PV-MF in 10, ET-MF in 10, and MPN/MDS overlap in 4 pts. Eight patients evolved to the MPN-blast phase prior to transplant. JAK-2 mutation was positive in 27 patients and negative in 12 patients with JAK-2 status unknown in 9 patients. The median time from PV/ET to MF was 136 months (83–189 months) and from MF diagnosis to transplant was 59 months (3–144 months). All but 2 patients were red cell transfusion dependent prior to transplant (96%). Eight patients underwent splenectomy prior to transplant. Transplantation Characteristics: Patients who underwent ASCT received either myeloablative (MA, 13 pts) or reduced-intensity conditioning (RIC, 35 pts) regimen. The graft was from an unrelated donor in 22 pts and related donor in 26 pts with 44 being matched and 4 being mismatched. The myeloablative regimens included Bu/Cy, TBI/Cy, and Bu/Flu. The RIC regimens included flu/mel, Bu/Flu, FBM, and TBI/Flu. GVHD prophylaxis was with tacrolimus/MTX, CSA/MTX, and tacrolimus/MMF. Nineteen patients received ATG. Infectious disease prophylaxis, CMV monitoring, and additional supportive care measures were according to institutional guidelines. A majority of patients received peripheral blood stem cells with only 1 patient receiving bone marrow as the source of stem cells. Outcomes: The median time to neutrophil engraftment was 17.2 days. Two patients received a second transplant for relapsed disease. The incidence of graft failure was 10%. Graft versus host disease both acute and chronic occurred in 33 patients and 15 patients respectively. Day 100 overall survival was 92% and 2 year survival was 62% (95% CI 45–75%). There were no statistically significant associations between individual prognostic factors (DIPSS-plus classification, age, and HLA match) and survival. Conclusions: The Mayo Clinic national experience of ASCT for MF across our geographically diverse Cancer Center is encouraging. Our centers have transplanted 48 patients over the past 10 years with very favorable outcomes. Our results from a multi center practice are consistent with regards to survival, graft versus host disease, and types of transplants being performed compared to currently available published data from large single location transplant centers. This data helps confirm the prevailing knowledge that ASCT is a useful treatment. Disclosures: Mesa: Incyte: Research Funding; Lilly: Research Funding; Sanofi: Research Funding; NS Pharma: Research Funding; YM Bioscience: Research Funding.

Abstract Abstract 1432 Previously we demonstrated that inhibition of anti-apoptotic BCL-2 family members sensitize leukemic cells to 5-Azacytidine (5-Aza), using siRNA and pharmacological inhibition with the BH3-mimetic ABT-737, both in vitro and ex vivo (Bogenberger, JM., et. al. ASH Annual Abstracts 2011;118:Abstract 3513). Crucially, several anti-apoptotic BCL-2 members (e.g. BCL-2 and BCL-XL) required concurrent inhibition for potent and universal sensitization to 5-Aza. Anti-apoptotic BCL-2 proteins block the execution of programmed cell death (apoptosis) by binding to and counteracting two types of pro-apoptotic BCL-2 family proteins: the “BH3-only” proteins, including both activators (BIM and BID) and sensitizers (e.g. NOXA, PUMA, HRK), and the multi-domain effector proteins (BAX and BAK). Cells dependent on anti-apoptotic BCL-2 family members for survival have been defined as “primed for death” (Certo, M., et. al. Cancer Cell 2006 May;9(5):351-65). Importantly, the priming status reflects a dependence on anti-apoptotic BCL-2 family proteins and can be characterized with the BH3 profiling functional assay. This assay measures induction of mitochondrial outer membrane permeabilization (MOMP) in response to treatment with peptides derived from BH3-only proteins (Ni Chonghaile, T., et. al. Science 2011 Nov 25;334(6059);1129-33). Thus, the unique BH3 profile associated with a specific malignant cell population, is a function of the anti-apoptotic BCL-2 family member/s contextual expression in that cell population. Based on our observations of potent 5-Aza sensitization in combination with anti-apoptotic BCL-2 protein family inhibition, we hypothesized that BH3-profiling would predict response to 5-Aza. To address the potential utility of BH3 profiling in predicting response to 5-Aza in myeloid malignancies, we assayed a broad panel of AML-derived cell lines (N=13) by BH3 profiling and correlated BH3 metrics with 5-Aza response. Identical cell line passages were assayed by BH3 profiling and in 5-Aza drug dose response assays. The cell panel comprised lines derived from AML FAB subtypes M7, M6, M5, M4, M2 and M0, as well as diverse cytogenetics such as t(11;21), t(9;11), t(4;11), t(6;11), del 5q, del 7, and a broad spectrum of mutations such as FLT3, N-RAS, CDKN2A, NPM1 and DNMT3A. The panel included a normal karyotype AML cell line (CG-SH) (Munker, R., et. al. Leuk Res 2009 Oct:33(10):1405-8) and a blastic cell line derived from a patient with MDS (MDS-L) (Tohyama, K., et. al. Br J Haematol 1994 Jun;87(2):235-42). Partition modeling using several BH3 metrics discriminates 5-Aza response with statistical significance (N=13, Mann-Whitney p<0.01) between more sensitive (EC50<2uM) and less sensitive (EC50>2uM) AML lines. For instance, the Puma BH3 peptide alone distinguishes more sensitive from less sensitive cell lines (N=13, Mann-Whitney p=0.0046). Several more complex parameters, such as “Puma+Hrk”, “Puma+Noxa,” and “Bim+Puma+Noxa+Hrk,” also significantly discriminate 5-Aza response (Mann-Whitney p=0.0011). Using continuous variable analysis, a Puma+Hrk metric exhibited the strongest correlation with 5-Aza response (R2=0.85, p<0.0001), while an individual Puma metric yielded the second strongest correlation (R2=0.70, p=0.0004). In conclusion, BH3 profiling discriminates 5-Aza response and confirms a central role for anti-apoptotic BCL-2 members in 5-Aza response. Furthermore, HRK priming indicates that BCL-XL is an important, although not the sole, anti-apoptotic component determining 5-Aza response in myeloid cells. These BH3 profiling results are in agreement with our functional 5-Aza RNAi and BCL-XL/BCL-2 inhibitor data in combination with 5-Aza. Based on these results, we are currently evaluating BH3 profiles from 5-Aza responding and non-responding AML and MDS patients to validate BH3 profiling-derived metrics in predicting clinical outcomes to 5-Aza. Disclosures: Pierceall: Eutropics Pharmaceuticals: Employment, Equity Ownership. Lena:Eutropics Pharmaceuticals: Employment. Mesa:Sanofi: Research Funding; Incyte: Research Funding; Lilly: Research Funding; NS Pharma: Research Funding; YM Bioscience: Research Funding. Cardone:Eutropics Pharmaceuticals: Employment, Equity Ownership.

Abstract Abstract 2741 Background: The novel agent lenalidomide (LEN) has shown significant single-agent activity in patients with relapsed lymphoma through anti-proliferative and immunomodulatory mechanisms. In combination LEN may synergistically improve the efficacy of rituximab. However, there is limited data on the efficacy and safety of LEN in multi-drug combination regimens for treatment-naïve patients. We designed a phase II single arm trial to evaluate tumor response, toxicity (AE) and survival with a combination of LEN, rituximab, cyclophosphamide (CTX) and dexamethasone (DEX) (LR-CD) in symptomatic untreated patients with indolent B-cell lymphoma. (NCT00784927). Methods: Eligibility required age ≥18, ECOG PS ≤2, confirmed diagnosis of indolent B-cell lymphoma (FL1–2, SLL, MZL or LPL/WM), measurable nodes ≥2cm or IgM ≥400mg/dL (LPL/WM), ANC ≥1400/mm3, platelets ≥100,000/mm3, creatinine ≤2mg/dL, and signed informed consent. Only patients needing therapy were considered eligible. Treatment consisted of IV rituximab 375mg/m2 D1, oral LEN 20mg D1–21, CTX 250mg/m2 D1, 8, 15, DEX 40mg D1, 8, 15, 22 and ASA 325 mg daily in a 28 day cycle. Treatment continued 2 cycles beyond best response up to a maximum of 12 cycles. Toxicity was assessed by NCI CTCAE v3.0. Results: Thirty-one patients have enrolled at Mayo Clinic with 28 evaluable for toxicity and response (1 deemed ineligible, 1 withdrew before treatment, 1 treatment violation). Four patients continue on study at this time. Patient characteristics: median age 68.5(43–83), 71% male, stage IV 86%, FL 28%, MZL 25%, LPL/WM 39%, and SLL 4%. Median number of cycles given was 6 and 71% completed the study per protocol. The best overall response is 89% with 32% CR and 57% PR. In subgroup analysis, the response rates for LPL/WM was 91% (all PR) and for FL 88% (CR 63%, PR 25%). The most common grade ≥3 AEs were neutropenia (35.7%), leukopenia (17.8%), anemia (14.3%) and thrombosis (14.3%). The LPL/WM subgroup experienced more grade ≥3 anemia (36%) compared to the group as a whole. Patients (57%) required at least one dose reduction of LEN (n =10), CTX (n = 9) or DEX (n = 7). At a median f/u of 14.5 (1.8–36.5) months 86% are progression free (fig. 1) and the OS is 96% (fig. 2). One death unrelated to treatment occurred 7.7 months after completing 12 cycles of treatment. Conclusion: Lenalidomide can be safely combined with other active agents and in the combination LR-CD produces high response rates in symptomatic patients with indolent B-cell lymphoma. The regimen is well tolerated with manageable toxicities which are similar to that seen with single agent LEN. The encouraging results seen in patients with LPL/WM have led to expansion of this cohort for additional study. Disclosures: Reeder: Celgene: Research Funding. Off Label Use: lenalidomide use in non-Hodgkin lymphoma. Stewart:Celgene: Consultancy, Honoraria.

Abstract Background: CLL patients (pts) treated with novel targeted therapies continue to experience disease progression. Approximately 7-15% of relapsed CLL treated with ibrutinib or venetoclax developed Richter's syndrome (RS), an aggressive high grade lymphoma transformation. Standard chemotherapy has limited efficacy in RS. We hypothesized that checkpoint blockade would re-establish anti-tumor immune response in progressive CLL/RS and here we aim to update the clinical data and correlative analysis of MC1485: a phase 2 study of PD-1 blocking antibody pembrolizumab in relapsed/refractory CLL and RS. Methods: Relapsed/refractory CLL including RS enrolled in the CLL arm of MC1485 trial was reported here. The primary end point of this study is overall response rate (ORR). Pts with prior allogeneic stem cell transplant were excluded. Pembrolizumab 200 mg was administered intravenously every 3 weeks. NCI CTCAE v4.0 and IWCLL 2008 criteria were used for non-hematological adverse events (AE) and for CLL grade hematological AE. Tumor expression of PD-1 and PD-L1 were assessed with standard immunohistochemical (IHC) staining. Percentage expressions of individual antigens were analyzed with whole-slide scanning followed by image analysis with Image-Pro software (Media Cybernetics). Fluorescence in situ hybridization (FISH) was performed on available CLL/RS tissue sections to assess copy number of chromosome 9p region that contains PD-L1 and PD-L2. Results: 25 pts including 16 CLL and 9 RS (biopsy-proven large cell lymphoma) were enrolled in CLL arm. The median age was 69 years (46-81). Twelve (48%) pts had del(17p) or monosomy 17 or TP53 mutation. The median number of prior therapies was 4 (1-10). 96%, 72% or 48% of pts had received alkylator and anti-CD20 antibody, purine analog or anthracycline. Fifteen (60%) pts had prior ibrutinib and 12 (48%) progressed clinically while receiving ibrutinib, including 6 who progressed to RS and 6 who developed progressive CLL. The median number of pembrolizumab doses that pts received was 3 (1 to 21), administered over a median treatment duration of 11 weeks (1 to 56). Drug-related AE occurred in 21 pts (88%) with the most common ones being neutropenia in 9 (37%), cough in 7 (29%) and dyspnea in 6 (25%) pts. Drug-related grade 3 or above AE occurred in 9 (38%) pts with most common ones being thrombocytopenia (5, 21%), dyspnea (2, 8%), and fatigue (2, 8%). The most common immune-related AE was liver enzyme elevation (12%, 8% G3) and was reversible with therapy interruption or steroid therapy. Based on investigator assessment using the Revised Response Criteria for Lymphomas and IWCLL 2008 criteria, one RS pt had complete response (CR, 4%), 3 RS had partial responses (PR, 12%). Among 9 RS pts, 1 CR (11%), 3 PR (33%), 3 SD (33%) and 2 PD (22%) were observed. Thus the ORR in RS was 44%. No CLL pts achieved a CR/PR, 3 had SD and 9 had progressive disease (PD). The ORR of all pts was 16%. Of the 4 RS who had CR/PR, responses occurred early after 2 cycles of therapy and median duration of therapy for CR/PR pts was 8.3 months with data cut-off by June 30th 2016 (Figure 1A). The causes for therapy discontinuation in RS were PD (3, 33%), alternate therapy (2, 22%), and thrombocytopenia due to increased marrow CLL (1, 11%). Increased marrow CLL was observed in 2 RS pts with PR to RS phase of disease assessed by PET, thus the protocol was amended to allow addition of idelalisib/ibrutinib to control the underlying marrow CLL. For RS pts who had a CR/PR or SD, variable nodal responses were observed (Figure 1B). In particular, 6 RS who had prior ibrutinib experienced CR or PR or SD with nodal responses. After a median follow-up of 10.2 (1.9 to 16.1) months, the median overall survival (OS) for all pts was 10.7 months (95% confidence interval [CI], 5.4 to not reached). The 6 month OS rate for RS and CLL pts were 73% and 59%, respectively. Biomarker assessment using IHC analysis on 10 pts with available tumor/nodal tissues (6 RS and 4 CLL) showed an increased expression of PD-L1 (p = 0.02) and a trend for an increased expression of PD-1 (p = 0.1) in the group of pts with CR/ PR versus pts in the group with no clinical response. One out of 10 tested showed polysomic for chromosome 9p. Conclusion: Pembrolizumab had an acceptable safety profile in CLL and RS patients. We confirmed that pembrolizumab has substantial therapeutic activity in RS. Single-agent pembrolizumab does not appear to have clear activity in CLL. Disclosures Ding: Merck: Research Funding. Parikh:Pharmacyclics: Honoraria, Research Funding. Shanafelt:GlaxoSmithKline: Research Funding; Genentech: Research Funding; Janssen: Research Funding; Pharmacyclics: Research Funding; Celgene: Research Funding; Cephalon: Research Funding; Hospira: Research Funding.