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Abstract Background L-asparaginase (LASP) therapy in adults is associated with frequent hepatic and metabolic side effects, often resulting in dose adjustments and omissions. Pegylated asparaginase (PEGASP) substituted for LASP improves convenience of administration with comparable efficacy; however, adverse event (AE) management remains challenging. The incidence and management of LASP- and PEGASP-induced metabolic and hepatic complications in adult ALL patients is not well defined. Methods This single center, retrospective, observational study was approved by the Mayo Clinic Institutional Review Board. Consecutive adult patients with a confirmed diagnosis of ALL receiving LASP or PEGASP containing chemotherapy regimens between January 2000 and October 2012 were evaluated. Patients were followed up to 60 days after the last LASP or PEGASP dose for development of biochemical and clinical pancreatitis, hypertriglyceridemia and hepatotoxicity. Hyperglycemia was not analyzed due to confounding variables, such as concomitant corticosteroid administration. AEs were graded as per the National Cancer Institute Common Terminology Criteria (CTCAE) version 4.03. Analysis was performed using Cox proportional hazard models with odds ratios (with 95% confidence intervals) reported to demonstrate the strength of association between group and AE rate. Results Of 74 adult patients, 54 (73%) met inclusion criteria. History of dyslipidemia, diabetes mellitus, cholelithiasis and coronary artery disease was documented at baseline in 13 (24%), 4 (7%), 4 (7%) and 10 (19%) patients, respectively. Twenty eight (52%) patients received LASP, 22 (41%) received PEGASP and 4 (7%) received both. A total of 399 doses including 335 (84%) LASP and 64 (16%) PEGASP were administered. Distribution based on treatment schedules was as follows; CALGB 9111 (n=20 (37%), Larson et al, 1998), E2993 (n=13 (24%), Goldstone et al, 2008), C10403 (n=9 (17%), NLM: NCT00558519), CCG 1941 (n=7 (13%), Gaynon et al, 2006) and Augmented Hyper-CVAD (n=5 (9%), Faderl et al,2011). Six (11%), 20 (37%), and 53 (98%) patients experienced pancreatic, lipid (hypertriglyceridemia) and hepatic adverse events, respectively. In this group, CTCAE grade 3/4 AEs occurred in 0 (0%), 8 (15%), and 28 (52%) patients, respectively. No deaths were directly related to these complications. Patients receiving PEGASP were more likely to experience AE of any CTCAE grade (OR 11.5, 95% CI 4.4-30.3, p < 0.0001), including grade3/4 AEs (OR 27.9, 95% CI 11.4-68.2, p < 0.0001) in comparison to those receiving LASP. All cases of pancreatitis manifested as biochemical elevation in pancreatic enzymes, and were either grade 1 (n=4, 67%) or grade 2 (n=2, 33%). All patients were managed conservatively. Management of hypertriglyceridemia was heterogeneous across all grades and included observation (n=11, 55%), non-pharmacologic interventions (n=1, 5%), medication management (n=4, 20%) and combined strategies (n=4, 20%). The most common practice was a combination of fibrate derivatives (fenofibrate) and fish oil (n= 5). One patient with a peak triglyceride level of 2285 mg/dL was placed on an insulin/dextrose infusion for 4 days. Hepatic toxicity manifested as CTCAE grade 3/4 transaminitis in 13 (24%) patients, hyperbilirubinemia in 4 (7%) patients and both in 11 (20%) patients. Temporal correlation was used to best distinguish confounding variables including possible hepatoxicity from azole antifungals and other drugs. Management of hepatic toxicity included delay in dosing, subsequent LASP or PEGASP dose reduction and laboratory monitoring until resolution. Overall, deviations in LASP or PEGASP administration were documented in 18 (33%) patients due to metabolic or hepatic AEs. Eight (15%) patients required omission of at least 1 dose, 7 (13%) experienced delays of administration and 7 (13%) needed a dose reduction. Conclusion PEGASP administration resulted in significantly higher AE rates in comparison to LASP and this significance was retained when comparing AEs of CTCAE grade 3 and 4. Given the growing trend of using PEGASP combination chemotherapy in adults with ALL, a detailed analysis looking at the increase in side effects, their consequences (delayed tereatment and dose reductions) and the impact of these factors on disease remission and survival is needed. Disclosures: No relevant conflicts of interest to declare.

Abstract Background Imetelstat is a 13-mer lipid-conjugated oligonucleotide that targets the RNA template of human telomerase reverse transcriptase. A pilot study of imetelstat therapy in myelofibrosis showed the induction of complete (CR) or partial remissions, as well as molecular remissions, in a subset of patients (Blood. 2014;124:634). In the particular study, CR was significantly higher in patients with SF3B1 or U2AF1 spliceosome mutations, which provided the rationale for the current study; spliceosome mutations are closely associated with refractory anemia with ring sideroblasts with (RARS-T) or without (RARS) thrombocytosis (Leukemia. 2013;27:1826). Methods Diagnosis of RARS and RARS-T was according to WHO criteria (Blood. 2009;114:937). Study patients were treated with a 2-hour intravenous infusion of 7.5 mg/kg imetelstat (Janssen Biotech Inc., Horsham, PA, USA) every 4 weeks. Drug activity was monitored by both formal response criteria (Blood. 2006;108:419) and effect on spleen size, thrombocytosis and leukocytosis. Adverse events (AEs) were monitored by Common Terminology Criteria for Adverse Events (Version 4.03). Laboratory correlative studies included analysis of mutations. Results Accrual to this signal study is now complete and median time from study registration, as of 5/10/2015, was 17.1 months (range 16.1-20.1). Among the 9 study patients, 5 had RARS-T, 3 had RARS and one had "MDS/MPN overlap". Median age was 70 years (78% males). 8 (89%) patients were transfusion-dependent. One patient (RARS-T) had marked splenomegaly (palpable at 16 cm). Three patients each had leukocytosis and thrombocytosis. Seven (78%) patients had received prior treatments, including erythropoiesis stimulating agents in 6 (67%). Baseline international MDS prognostic scoring system scores were intermediate-1 (n=7) and intermediate-2 (n=2). Karyotype was normal in all but one patient with loss of Y chromosome. Drug activity Median duration of treatment with imetelstat was 13.7 months (range 6.6-17.9). Three (38%) patients achieved transfusion-independence (TI) during treatment, defined as not requiring transfusions for at least 8 weeks; 2 had RARS and one RARS-T. The median time to TI was 11 weeks (range 9-14) and the median TI duration was 28 weeks (range 9-37). One of the 3 "TI" patients also had resolution of leukocytosis and thrombocytosis. A 4th patient experienced >50% decrease in palpable spleen size as well as a decrease in transfusion need. In addition, imetelstat induced normalization of counts in two additional patients with thrombocytosis and leukocytosis. As of 5/10/2015, 4 (44%) patients remain on active treatment and one death had been recorded (deemed unrelated to imetelstat). The 5 treatment discontinuations were: death during active therapy, discovery of second malignancy, progression into acute leukemia and insufficient response (n=2). Safety Treatment-emergent grade 4 neutropenia and thrombocytopenia were seen in 2 (22%) and 1 (11%) patients, respectively; neutropenia, and thrombocytopenia were seen in 4 (44%), and 2 (22%) patients. Grade 3 anemia was seen in 6 (67%) of the patients, however baseline grade 2 anemia was noted in 2 (22%) and grade 3 in 3 (30%) patients. None of the grade ≥3 hematologic toxicities lasted ≥4 weeks.. The following grade 3 non-hematologic events occurred in 1 subject: aspiration, fatigue, and lipase increase and a patient with pre-existing cardiovascular disease history experienced a grade 5 heart failure. Treatment-emergent liver function test abnormalities affected: ALT (grade 1 56%/grade 2 11%), AST (grade 1 56%/grade 2 11%), ALP (grade 1 33%), and total bilirubin (grade 2 11%). For patients that discontinued treatment with imetelstat, these events were mostly reversible. Mutation studies Patients were screened for mutations involving JAK2, SF3B1, U2AF1 and SRSF2. Three patients were mutated for JAK2, 7 for SF3B1 (4 K700E, 2 H662Q, one K666N) and one for U2AF1 (Q157P). All three patients with "TI" (H662Q, K700E, K666N) and the 4th patient with spleen response (K700E) were SF3B1mutated. Post-treatment analysis showed no effect of imetelstat on mutations. Conclusions Treatment with imetelstat may offer clinical benefit in patients with RARS or RARS-T with generally acceptable safety profile and warrants further clinical investigation. Disclosures Al-Kali: Celgene: Research Funding. Wan:Janssen Research & Development: Employment, Equity Ownership.

Abstract Background: Myelodysplastic syndromes (MDS) are clonal hematological diseases which present with cytopenias. Hematopoietic cell transplantation is usually limited to fit patients with higher risk MDS and donor availability. Hypomethylating agents (azacitidine and decitabine) have been the mainstay option for the management of MDS with different clinical efficacy in low versus high risk MDS trials. No trials have compared the two agents. Aim: To conduct a systematic review and network analysis comparing the efficacy of azacitidine to decitabine. Methods: The protocol of the systematic review was developed a priori. A comprehensive search of several databases (MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, and Scopus) was conducted from each database's earliest inception through November 20th, 2014 without language restrictions. Trials enrolling adults diagnosed with MDS who received hypomethylating agents (azacitidine or decitabine) therapy were included. Studies were screened by two independent reviewers and differences were resolved by consensus. The Cochrane Risk of bias tool was used to appraise the trials. Random effects model was used to pool relative risks (RR) of outcomes (overall survival, overall response rate, hematologic improvement and grade 3 or 4 toxicity). Adjusted indirect comparisons were used to estimate RR for indirect comparisons (Glenny AM, et al. Health Technol Assess. 2005). All statistical analyses were conducted using STATA, version 13 (StataCorp LP, College Station, TX). Results: Only four trials met the eligibility criteria (Figure 1). Two trials compared Azacitidine (75mg/m²/day SC x 7 days) to the best suppurative care (BSC) and included 549 patients (278 azacitidine and 271 BSC, age average: 69; range: 31-92), and the other 2 compared decitabine (15 mg/m² IV q 8 hours x9) to BSC and included 403 patients (208 Decitabine and 195 BSC, age average: 69.7; range: 60-90) (Table 1). The proportion of patients with intermediate-2 and high-risk myelodysplastic syndrome (based on International Prognostic Scoring System (IPSS)) in trials comparing decitabine to BSC was 82.21% and 83.08%; respectively, and in trials comparing azacitidine to BSC was 62.59% and 61.26%; respectively. The risk of bias was moderate overall. Compared to BSC, azacitidine was significantly associated with lower risk of death (RR=0.83, 95% CI: 0.74-0.94, p=0.002) whereas the effect of decitabine did not reach statistical significance (RR=0.88, 95% CI: 0.77-1.001, p=0.053). Both drugs were superior to BSC in terms of partial and complete response. Head to head comparisons were not statistically significant (except for the outcome of complete response where low certainty evidence suggested that azacitidine treated patients were less likely to have complete response compared to decitabine (RR=0.11, 95% CI= 0.01, 0.86, p=0.04). (Table 2). Conclusion: Azacitidine and decitabine are both superior to BSC. The available indirect evidence comparing the two agents warrants low certainty and cannot reliably confirm superiority of either agent. Head-to-head trials are needed. In the meantime, the choice of agent should be driven by patients' preferences, drug availability and cost. Table 2. Results of meta-analysis Outcome Azacitidine VS. Decitabine Azacitidine VS. BSC Decitabine VS. BSC RR LCI HCI P value RR LCI HCI P value RR LCI HCI P value Death 0.95 0.79 1.13 0.54 0.83 0.74 0.94 0.002 0.88 0.77 1.001 0.05 Complete response 0.11 0.01 0.86 0.04* 2.56 1.44 4.58 0.001 23.46 3.22 170.84 0.002 Partial response 0.35 0.04 3.03 0.34 4.91 2.27 10.63 <0.0001 14.02 1.87 105.08 0.01 Major erythroid improvement 0.47 0.03 8.37 0.60 6.37 3.93 10.33 <0.0001 13.67 0.79 235.57 0.07 Major platelet improvement 1.51 0.30 7.56 0.62 4.80 2.98 7.70 <0.0001 3.19 0.68 14.89 0.14 Major neutrophil improvement 2.89 0.56 14.82 0.20 2.63 1.68 4.12 <0.0001 0.91 0.19 4.38 0.907 Hematologic improvement 0.25 0.06 1.09 0.07 2.18 1.67 2.85 <0.0001 8.62 2.05 36.32 0.003 Anemia 1.18 0.53 2.63 0.69 0.89 0.75 1.06 0.198 0.76 0.35 1.66 0.49 Neutropenia 0.99 0.75 1.30 0.92 1.87 1.63 2.14 <0.0001 1.90 1.49 2.42 <0.0001 Thrombocytopenia 0.87 0.64 1.18 0.37 1.63 1.43 1.86 <0.0001 1.87 1.43 2.45 <0.0001 Infection 1.13 0.52 2.43 0.76 1.25 0.60 2.60 0.55 1.11 0.87 1.42 0.41 *These results warrant low certainty due to imprecision (very small number of events) and are driven by 14 patients achieving complete response in BSC arm in one trial. Disclosures Al-Kali: Celgene: Research Funding.

Abstract Introduction Erlotinib is an epidermal growth factor receptor small-molecule inhibitor and is FDA approved for the treatment of lung and pancreatic cancers. In preclinical study, in vitro colony culture assays revealed that erlotinib at micro-molar concentrations effectively suppressed the growth and expansion of Polycythemia Vera (PV) hematopoietic progenitor cells while having little effect on normal cells. Several JAK inhibitors are being studied for the management of PV, one of which has been approved for the treatment of myelofibrosis (ruxolitinib). Aim To study the clinical effect of erlotinib in pts diagnosed with JAK2V617F + PV. Methods We conducted a single arm, prospective phase II study at the University of Oklahoma and the Oklahoma City VA hospitals in pts with WHO defined JAK-2 V617F positive PV from June 2010 to August 2012. Appropriate IRB approval was obtained in accordance with Hilsinki declaration. Pts had to be requiring phlebotomy. Toxicity was assessed by treating physicians using NCI version 4. Dose modification for erlotinib was done using label recommendations. Results Five Caucasian pts were enrolled (3 (60%) males, with median age at enrollment of 63 years, range 26-79). Pts had pretreatment median hemoglobin14.4 g/dL (10.4 -19.2 g/dL), median platelet count 511 x109 (424-681 x109), median white blood cell (WBC) 14.4 x109(7.8- 18.3 x109). Three pts had splenomegaly prior to treatment. Median number of prior pharmacologic treatments (hydroxyurea, anagralide or interferon) was 1, range 0-2. Pts were given erlotinib 150 mg orally daily for 16 weeks: responders (phlebotomy free or decrease in spleen size) were allowed to continue a total of 1 year of treatment, while non-responders were taken off the study. Three (60%) patients received therapy for 16 weeks and did not achieve hematological response or improvement in spleen size. Two (40%) pts were taken off the study after 2 doses secondary to severe toxicities (grade 3 colitis in 1 case, and grade 3 facial rash in 1case). No therapy continued beyond 16 weeks (due to toxicity or lack of response). All pts in the study developed rash (grade 1 – 3) and diarrhea (grade 1 – 2). Three pts developed mucositis (see Table 1). No death was observed during the study and follow up period (median follow up was 23 months, range 12-37 months). Study was closed due to lack of efficacy. Conclusions Despite in vitro efficacy of erlotinib as potent inhibitor of JAK-2 activity, erlotinib is not effective in pts with JAK-2 V617F positive PV with poor toxicity profile. Poor accrual was related to potential toxicity of erlotinib compared to alternative treatments in view of lack of clinical efficacy. Disclosures: No relevant conflicts of interest to declare.

Abstract Background Chronic myelomonocytic leukemia (CMML) is a clonal hematologic disorder that was classified by the World Health Organization (WHO) as a myelodysplastic/ myeloproliferative overlap disease. Cytogenetic abnormalities have a significant prognostic role in many hematologic neoplasms, but their prognostic value in CMML has been debatable. Recently, monosomal karyotype (MK) has been reported to be a marker of poor prognosis in patients with myelodysplastic syndromes (MDS) and primary myelofibrosis, but its value in CMML is unknown. Aim To study MK effect on clinical outcome for patients diagnosed with CMML Method A retrospective study of all cases diagnosed with CMML at Mayo Clinic Rochester between 1994 to 2011 was performed. Only pts with complete cytogenetic analysis at presentation to our institution were included. MK was defined as the presence of ≥ 2 autosomal monosomies or one autosomal monosomy with at least one structural abnormality (Breems et al, JCO 2008). CK was defined as the presence of at least 3 chromosomal abnormalities. Appropriate IRB approval was obtained in accordance with Helsinki declaration. Comparison between groups’ medians was done using Wilcoxon test, while survival estimates were calculated using Kaplan-Meier curves using JMP V9. Results A total of 262 pts diagnosed with CMML had available cytogenetic data at diagnosis. Median age was 72 years, 176 (67%) were male. Median hemoglobin 10.5 g/dL, white blood cells (wbc) 12 x109/L, platelet 89 x109/L, peripheral blood (PB) blast 0, and bone marrow (BM) blast 4%. CMML2 was seen in 9% while 47% were proliferative (wbc >13). Leukemic transformation was documented in 34 pts (13%). Median overall survival was 513 days. Cytogenetic (CG) analysis was diploid in 167 pts (64%). Trisomy 8 was the most frequent cytogenetic abnormality at 8% (22), followed by complex karyotype (CK) 5% (14), then -7 at 4% (10) and MK 3% (7, six of which were also CK). Comparing pts with diploid CG to other categories indicates: to abnormal CG pts had lower wbc (0.001), PB blasts (p<0.0001), and BM blasts (p=0.0001); to CK pts had lower PB blasts (p=0.003) and higher platelets (p=0.03); to -7 pts had lower wbc (p=0.005), PB blast (p=0.0004), BM blasts (p=0.03) and higher platelets (p=0.03); to +8 pts had lower PB blast (p=0.02) and BM blasts (p= 0.01); no difference was noted when compared to MK. Median OS was statistically significantly worse in MK+ vs MK- (24 vs 527 days, p= 0.002), but not in other comparisons: -7 vs others (250 vs 527 days, p=0.2), CK+ vs CK- (256 vs 527 days, p=0.05), diploid vs others (570 vs 365 days, p=0.1), +8 vs others (312 vs 527 days, p=0.1). Pts with MK+ only or MK+CK+ did worse than CK+ only or other groups (4, 63, 304, 527 days, respectively, p<0.0001). On a multivariate analysis, MK+ (in addition to platelet, BM blast, hemoglobin, and wbc) did have an impact on OS (p=0.0004), while CK+, -7, +8, diploid CG, age, PB blast did not. Conclusion Cytogenetic abnormalities were not frequent findings in pts diagnosed with CMML (36%), but did affect wbc, PB and BM blasts. The most common cytogenetic abnormality was +8 while MK was present at 3% (less than published data in MDS). Only MK predicted statistically significant shorter mOS between all other cytogenetic categories on both univariate and multivariate analysis. This finding needs to be validated by larger cohorts of pts due to its rare occurrence in CMML. Disclosures: No relevant conflicts of interest to declare.

Abstract Abstract 460 Background: SF3B1 mutations were recently reported to occur in myelodysplastic syndromes (MDS), especially in the presence of ring sideroblasts (RS) (Papaemmanuil et al. Leukemia Research 2011, Volume 35, Supplement 1, page S18). We sought to accurately define the interaction between SF3B1 mutations, bone marrow morphology, karyotype and prognosis in MDS with ≥15% RS (MDS-RS). Methods: Mayo Clinic databases and cell banks were queried to identify patients with MDS and ≥15% RS (MDS-RS). All study patients were required to have undergone bone marrow examination and cytogenetic evaluation at diagnosis. Pathology slides, including iron stains, were centrally re-reviewed to accurately quantify bone marrow RS percentage and confirm World Health Organization (WHO) morphologic categories. Detailed analysis of clinical and cytogenetic parameters was performed to risk stratify patients according to the revised International Prognostic Scoring System (IPSS-R) (Greenberg et al. Leukemia Research 2011, Volume 35, Supplement 1, page S6). All patients were annotated for their mutational status involving JAK2, MPL and IDH. PCR sequencing was used to identify SF3B1 mutations. Results I: Baseline patient information: The study is currently ongoing; to date, results are availab1e in 88 patients (median age 72 years, 69% males) including 36 (41%) patients with refractory anemia with RS (RARS), 36 (41%) with refractory cytopenia with multilineage dysplasia and ≥15% RS (RCMD-RS), 11 (12%) with refractory anemia with excess blasts (RAEB)-1 and ≥15% RS (RAEB1-RS) and 5 (6%) with RAEB2-RS. Median (range) values were 9.1 g/dL (5.8–15.7) for hemoglobin, 4.1 × 109/L (1.2–35.2) for leukocytes and 164 × 109/L (6–585) for platelets. IPSS-R risk categories were 20% very good, 49% good, 11% intermediate, 3% poor and 16% very poor. Karyotype was normal in 60%, other very good/good risk 16%, intermediate-risk 2%, and poor/very poor in 22%; 14% had monosomal karyotype (MK). Six (7%), four (5%) and zero (0%) patients displayed IDH, JAK2 or MPL mutations. Red cell transfusion need was documented in 27 (31%) patients. Results II: Prevalence and distribution of SF3B1 mutations and clinical correlates: SF3B1 mutations (all heterozygous) were detected in 40 (∼46%) of all 88 study patients: 25 (63%) K700E, 6 (15%) K666N/Q/R, 3 (8%) E622D, 2 (5%) H662D/Q, 2 (5%) Y623C, 1 (3%) R625C, and 1 (3%) T663I. One patient each displayed both SF3B1K700E and IDH2R140Q or SF3B1K700E and JAK2V617F. SF3B1 mutational frequencies were 69% for RARS, 36% for RCMD-RS, 18% for RAEB1-RS and 0% for RAEB2-RS (p=0.0007). SF3B1 mutations clustered with normal (59%) and other very good/good risk (57%) karyotype and were infrequent in poor/very poor karyotype (5%; p=0.0004). Additional significant correlations were noted between SF3B1 mutations and lower IPSS-R risk category (p=0.0004), advanced age (p=0.006), higher platelet count (p=0.0003). Results II: SF3B1 mutations and prognostic relevance in MDS-RS: To date, 68 (∼77%) deaths and 10 (∼11%) leukemic transformations have been documented. Median follow-up for living patients was 82 months. Univariate survival analysis considering all 88 study patients identified the following as strongly significant risk factors: IPSS-R (p<0.0001), WHO morphologic categories (p<0.0001), cytogenetic risk categories (p<0.0001), and transfusion need (p=0.0003). In multivariable analysis, only IPSS-R and transfusion need remained significant. In univariate analysis, the presence of SF3B1 mutations was significantly associated with better overall (p=0.04) and leukemia-free (p=0.03) survival; however, in both instances, significance was completely accounted for by WHO morphologic risk categorization and the morphology-adjusted p values were 0.6 and 0.2, respectively. In other words, when RARS and RCMD were analyzed separately, there was no additional prognostic value from the presence or absence of SF3B1 mutations (Figures 1 and 2; p=0.67 and 0.44, respectively). Conclusions: SF3B1 mutations are prevalent in RARS and RCMD-RS but do not provide additional, WHO morphology-independent or IPSS-R-independent, prognostic information. Disclosures: No relevant conflicts of interest to declare.

Abstract Background: Treatment-related AML (t-AML) accounts for 10 to 20% of all AML cases and carries an especially poor prognosis (Kayser et al. 2011, Godley et al. 2008). Patients diagnosed with t-AML are likely to have abnormal cytogenetic profiles with chromosome changes that are predictive of an aggressive malignancy, poor response to therapy, and decreased overall survival(Smith et al. 2003). The simultaneous use of multiple chemotherapeutic agents of different classes makes it increasingly difficult to predict risk for developing t-AML and determining disease course. An updated analysis of predictive factors for t-AML is needed so clinicians can more accurately inform patients of their prognosis. The aim of this study was to classify t-AML according to primary malignancy, previous chemotherapy exposure, and cytogenetic profile. Methods: A retrospective chart review of patients that were diagnosed with AML at Mayo Clinic from 7/1/1990 to 5/13/2015 was performed following IRB approval. AML patients found to have a previous malignancy treated with chemotherapy were classified as t-AML. Chemotherapeutics were classified as alkylating agents, antimetabolites, anti-tubulin agents, and topoisomerase II inhibitors. Patients diagnosed with a myelodysplastic or myeloproliferative disorder prior to development of AML were excluded from this study. Previous chemotherapy exposures, duration of chemotherapy exposure, complete blood count, chromosome abnormalities, and survival data were collected for t-AML cases. Cytogenetic changes were classified as favorable, intermediate, and adverse according to the system used by Kayser et al. 2011. JMP 10.0 was used for statistical analysis. Results: Out of 584 patients, 64 patients (11%) had a primary malignancy that was treated with chemotherapy prior to being diagnosed with AML. The most common primary malignancies were breast cancer (31%), non-Hodgkin lymphoma (27%), colorectal cancer (8%), and Hodgkin lymphoma (8%). Laboratory findings showed median hemoglobin 9.6 g/dL (4.7-13.8), median white blood cells 3.2 x109 (0.6-126), median platelets 50x109 (3-320), median peripheral blood blasts of 8% (0-91), and median bone marrow blasts 38% (1-94). 95% of patients diagnosed with t-AML had been previously treated with an alkylating agent. Additional exposure to an anti-metabolite trended towards a more adverse cytogenetic profile (χ2=5.0, p=0.08) but there was not a statistically significant decrease in overall survival (KM analysis, p=0.31). The median overall survival for patients diagnosed with t-AML was 10.2 months compared to 19.2 months for patients with de-novo AML (KM analysis, p=0.04). Adverse cytogenetic profiles were associated with decreased survival (KM analysis, p <0.0001). However, there was no difference in overall survival between patients with t-AML that had intermediate cytogenetics and those with de-novo AML (KM analysis, p=0.36). None of the chemotherapy classes other than antimetabolites were associated with poor cytogenetics or survival when combined with an alkylating agent. Conclusion: Over half of all patients classified as having t-AML in this study received prior chemotherapy for breast cancer or non-Hodgkin lymphoma. Cytogenetic classification of t-AML into favorable, intermediate and adverse groups is useful in predicting disease course. Interestingly, t-AML patients with intermediate risk cytogenetics had similar overall survival to patients with de-novo AML. This suggests that the poor outcomes observed in patients with t-AML is predominantly due to the subset with adverse cytogenetics. Thus, cytogenetic analysis remains the best indicator of overall survival regardless of chemotherapy exposure. Additional work is needed to delineate the risk associated with the aforementioned chemotherapy classes. Disclosures Al-Kali: Celgene: Research Funding.

Abstract Background: Induction therapy with daunorubicin (Dauno) & cytarabine (Ara-C) [DA] has been the standard of care for eligible older adults (age ≥ 60 years) with newly diagnosed acute myeloid leukemia (AML) for over 2 decades. Single agent Clofarabine (CLO) induction & consolidation (Consol.) therapy has demonstrated important clinical activity in this age group in large phase II studies. Lower induction mortality (IM) & similar reported complete remission rate (CR) & overall survival (OS), as well as notable activity in those with higher risk disease features [including unfavorable cytogenetics, therapy-related AML (t-AML) & prior antecedent hematologic disorder (AHD)] raises the possibility that a non-Ara-C-based regimen could achieve similar or superior OS with lower toxicity. Methods: We performed a randomized United States Intergroup Phase III trial of single agent CLO [30mg/m2 x 5 days induction; 20 mg/m2 re-induction (if indicated) & 2 cycles Consol.] vs. standard DA therapy [Dauno 60mg/m2 D1-3 & Ara-C 100mg/m2 D1-7 induction x 1-2 cycles; 2 cycles Consol. with Ara-C (1.5g/m2 Q12hrs D1-6 age 60-69; once daily if age 70+)] in patients (pts) age ≥ 60 yrs with newly diagnosed AML. Patients with serum creatinine >1.0 (or GFR <60 mL/min) and those with AML-M3 and ECOG performance status >3 (PS>2 if age 70+ yrs) were excluded. Randomization was stratified by age (60-69 vs. 70+), t-AML, & AHD. Pts with HLA-matched donor were eligible for allogeneic transplantation (AlloHCT) after induction, and those completing Consol. were eligible for randomization #2 (R#2) to maintenance decitabine [20mg/m2 x 3D, monthly x 1 year] versus observation. With a target accrual of 747, E2906 was powered to determine non-inferiority [and possible superiority] of CLO vs. standard DA, and primary endpoint was OS. A weighted statistical analysis was performed to account for confounding impact of R#2. AlloHCT patients were censored at transplant in this analysis. Responses & cytogenetics were confirmed centrally and OS & CR rates were monitored by an independent Data Safety Monitoring Committee (DSMC) at pre-specified time points. Results: As of Feb 23, 2015, 727 pts were randomized. Median age was 68 years (range 60-86); 57% were male, and 38% were age ≥70 yrs. Treatment arms are well balanced for all baselineclinical & AML characteristics, & 30% had unfavorable cytogenetics. Of 659 with complete treatment information reported, 30.4% on DA vs. 40.1% on CLO received 2 cycles of induction (p=0.006). Median follow-up of surviving patients is 7.6 months. Table 1. shows early treatment results (CR, toxicity) for the 686 pts randomized as of Dec 23, 2014 (2 months prior to study end, & excluding 90 with ongoing response evaluation). DA CLO p-value CR/CRi 43.8% 42.8% p=0.87 30-day mortality 8.5% 7.9% p=0.89 60-day mortality 14.9% 13.1% p=0.58 Gr 4-5 Non-Heme Tox.Induction 27% 19% p=0.02 Gr 4-5 Non-Heme Tox.Consol. 20% 7% p=0.001 374 pts have died (174, DA; 200, CLO) & significantly inferior OS was observed for CLO vs. DA [Hazard Ratio (HR) 1.41 (95% CI 1.12-1.78)] (Fig. 1). Planned subgroup analyses were performed (Table 2) demonstrating significant differences in OS after CLO for patients age 60-69 yrs, without AHD, & with intermediate risk cytogenetics; but not for those with Unfav. Cytogen. (Fig. 2) or t-AML. Based on the primary weighted analysis, DSMC recommended suspension of new accrual to E2906 on Feb 23, 2015 & all active patients on CLO were transitioned to DA Arm. Table 2.NHR CLO/Standard (95% CI)*Weighted OS7271.41 (1.12-1.78)Unweighted OS7271.23 (1.00-1.50)Age 60-694491.48 (1.10-1.99)Age 70+2781.34 (0.93-1.93)Intermed. Risk Cytogen.3781.77 (1.27-2.47)Unfav. Risk Cytogen.2160.96 (0.65-1.43)No AHD6041.46 (1.13-1.89)AHD1231.22 (0.74-2.00)De novo AML6271.52 (1.18-1.96)Therapy-related AML1000.94 (0.54-1.61) Conclusions: Despite similar CR & IM, OS after single agent CLO is inferior to standard DA therapy for pts age ≥60 years with newly diagnosed AML who are fit for intensive therapy, and DA remains the standard of care. However no difference in OS was observed after CLO in some pre-specified high risk AML subgroups. R#2 & AlloHCT arms continue in E2906 for pts already enrolled. Embedded prospective minimal residual disease study at CR is being performed to identify pts at higher risk after CLO & DA. Figure 1. Weighted Kaplan-Meier Curves for OS Figure 1. Weighted Kaplan-Meier Curves for OS Figure 2. Unfavorable Cytogenetics OS by Therapy Figure 2. Unfavorable Cytogenetics OS by Therapy Disclosures Off Label Use: Use of clofarabine in AML, and maintenance therapy with decitabine in AML. Claxton:Medimmune: Research Funding; BMS: Consultancy; Astellas: Research Funding; Cyclacel: Research Funding; Merck: Research Funding; Ambit: Research Funding. Levine:Loxo Oncology: Membership on an entity's Board of Directors or advisory committees; CTI BioPharma: Membership on an entity's Board of Directors or advisory committees; Foundation Medicine: Consultancy. Altman:Seattle Genetics: Consultancy; BMS: Consultancy; Spectrum: Consultancy; Astellas: Consultancy; Ariad: Consultancy; Novartis: Consultancy. Al-Kali:Novartis: Research Funding.

Abstract Background The impact of cytomegalovirus (CMV) infection on the risk of relapse after Hematopoietic Cell Transplantation (HCT) remains controversial, with some studies demonstrating lower risk (Green et al, Blood 2013), while others demonstrating no impact (Schmidt-Hieber et al, Blood 2013), or lower relapse risk only in myeloablative (MA) (Manjappa et al, BBMT, 2014) or in reduced intensity conditioning (RIC) (Cichocki et al, ASH 2014) HCT. Furthermore, the majority of studies have used antigenemia for CMV monitoring, while there is limited data with the use of Quantitative Nucleic Acid Testing (QNAT). Aim To determine the impact of CMV infection, as detected by QNAT, on transplant-related outcomes for patients with acute myeloid leukemia (AML), stratified by MA or RIC HCT. Methods After IRB approval, consecutive adults with AML who underwent allogenic HCT from HLA-matched peripheral blood (PB) grafts at our institution between 2006 and 2014 were retrospectively reviewed. All grafts were T-cell replete. Early CMV infection was defined as any positive CMV result by PCR assay during the first 100 days post HCT. Relapse incidence (RI), non-relapse mortality (NRM), disease-free survival (DFS), and overall survival (OS) were compared between patients with and without CMV infection, and stratified according to MA or RIC. DFS and OS were estimated using the Kaplan-Meier method, and compared with log-rank test. Cumulative incidence of relapse and NRM were analyzed as competing events, using Gray's test. Multivariable analyses adjusting for patient's age, disease status at transplant, cytogenetic risk, and ABO incompatibility were performed using Cox's proportional hazards regression, and the Fine and Gray approach. Results A total of 190 consecutive patients, including 94 (49%) MA and 96 (51%) RIC HCT were analyzed. Patients, disease, and transplant characteristics are shown in table 1. Of the 94 MA HCT (median age 45 y, 50% male), 66 (70%) received total body irradiation. After a median follow up of 18 m, 36 (38%) CMV infection, 16 (17%) relapses, 22 (23%) NRM and 35 (37%) deaths occurred in the MA group. Median time to CMV infection and to relapse in this group was 38 (range 8-241) and 140 (29-1690) days, respectively. Among the recipients of MA HCT, patients with early CMV infection showed no difference in the RI (figure 1), but had a significant trend towards higher NRM and significantly lower DFS and OS in both univariate and multivariable analysis (figure 2) (P values shown in table 2). Among 96 RIC HCT (median age 59 y, 56% male), fludarabine plus melphalan was used in 62 (65%) and fludarabine plus busulfan in 34 (35%) patients. In this group, early CMV infection occurred in 33 (34%), relapse in 25 (26%), NRM in 25 (26%), and deaths in 46 (48%) patients after a median follow up of 21 m (1-91 m). Among the recipients of RIC HCT, median time to CMV infection and to relapse was 40 (17-175) and 291 (19-1971) days, respectively. In the RIC group, early CMV infection was associated with a significant trend towards lower RI (figure 1) and higher NRM in both univariable and multivariable analysis, but no difference in DFS and OS (figure 2). Conclusion Our study of a large homogenous group of AML patients who underwent a uniform HLA-matched PB HCT demonstrates a significantly lower risk of relapse associated with early CMV infection detected by QNAT following RIC, but not MA HCT. Early CMV infection in MA HCT is associated with higher NRM and therefore inferior survival, whereas in the RIC HCT, there is no impact on survival as the benefit of lower relapse is offset by the higher NRM. Table 1. Patients, disease and transplant characteristics according to CMV infection All Patients Patients with CMV Viremia Patients without CMV Viremia P value Patients, no (%) 190 (100) 69 (36) 121 (64) - Median age, y (range) 54 (18-72) 54 (26-70) 54 (18-72) 0.75 Male Patients, no (%) 104 (55) 30 (43) 74 (61) 0.02 D/R CMV Serostatus, no (%) <0.0001 -/- 29 (15) 1 (1) 28 (23) +/+ 64 (34) 35 (51) 29 (24) +/- 13 (7) 1 (1) 12 (10) -/+ 84 (44) 32 (47) 52 (43) Conditioning 0.65 MA 96 (51) 33 (48) 63 (52) RIC 94 (49) 36 (52) 58 (48) Disease status at Transplant 0.96 CR1 129 (68) 46 (67) 83 (69) CR2 34 (18) 13 (19) 21 (17) Other 27 (14) 10 (14) 17 (14) Cytogenetic 0.65 Favorable 8 (4) 2 (3) 6 (5) Intermediate 130 (68) 46 (67) 84 (69) Unfavorable 52 (28) 21 (30) 31 (26) Disclosures Al-Kali: Novartis: Research Funding.

Abstract Background: Hypomethylating agents (HMA) such as 5-Azacitidine (Aza) have overall responses rate of ~35-50% in acute myeloid Leukemia (AML) and higher risk myelodysplastic syndrome (MDS) patients (pts). However, eventually all pts develop resistance on therapy. To improve upfront response rates and to address HMA failure, we performed genome-scale RNAi screens targeting genes on chromosomes 5 and 7, recurrent cytogenetic abnormalities in AML/MDS. These screens identified Hedgehog pathway (Hh) genes as potentially targetable vulnerabilities with Aza. Combination experiments with smoothened (SMO) inhibitors (SMO is a central activating gene within the Hh pathway) showed pre-clinical synergy. These and additional published data support the Hh pathway as a targetable vulnerability in AML, and provide a rational for a trial. Methods: A phase I/Ib protocol of the oral SMO inhibitor LDE225 (Sonidegib) in combination with Aza in untreated and relapsed/refractory (rel/ref) AML, chronic myelomonocytic leukemia (CMML), MDS, or MDS/myeloproliferative neoplasm overlap pts. Objectives of the phase I part are to determine safety, toxicity and MTD and for the phase Ib part to assess the preliminary overall efficacy. Sonidegib was started at dose level (DL) 0 at 400mg oral daily continuously and Aza at the approved doses (75mg/m2 x 7 days or days 5-2-2) with dose adjustment per label. A classical 3+3 design was used and DLT (CTCAE v4.0) defined as > grade 3 CPK elevation or hepatic or non-hematologic adverse events (AEs) lasting > 7 days or any grade 4 event, except for hematologic toxicities. DLT was assessed after 42 days when steady-state concentrations of Sonidegib were reached. Pharmacokinetic assessments were not performed for this study. Results: Patients and Dose Levels : Between 5/22/2014 and the data cut-off date (7/20/2015), 36 pts were enrolled. Median age was 72 y (range 52-85 y) and 64% were male. Most AML pts (23 of 24) had intermediate or unfavorable cytogenetics and most MDS/CMML pts were in the int.- to high-/very high-risk group (IPSS-R). Six pts were treated at DL-0 of Sonidegib 400mg/day and one DLT of CPK elevation was observed. Another patient had grade 4 neutropenia (which at the time was included in the DLT definition, later removed). Due to overall tolerance of the combination at DL 0 and investigator assessment, despite only 1/6 pts having a formal DLT, DL -1 at Sonidegib 200mg was explored at which 0/3 pts (1 pt non-evaluable) had DLT and the phase Ib portion was opened at DL -1. To date a total of 24 AML (13 newly dx, 11 rel/ref), 11 MDS/CMML (5 newly dx, 6 rel/ref ) and 1 myelofibrosis pt have been enrolled. Safety and Tolerability: An initial safety and efficacy assessment for 25 of the 29 pts treated on the phase Ib (n=26) + the MTD cohort of 200 mg (n=3) and for who at least 2 cycles of treatment follow up was available, showed that all pts experienced at least one grade-3 or 4 hematologic AE with a lower rate in the untreated vs. treated cohort. Other, non-hematologic grade-3 and 4 AEs respectively were seen in 24 and 28% of patients-most commonly hyponatremia and fatigue, known AEs for this drug class. Treatment delays occurred in 28% of pts and Aza or Sonidegib dose reductions in 16%. 23 (79%) pts are alive and 6 have died (21%), with one death while pt was actively treated but was deemed unrelated; 11 pts remain on study, with the remainder showing disease progression (n=3) or taken-off study for other reasons (n=3 each for AEs and did not want further treatment; n=4 other). Efficacy : As of 7/20/15 with a median treatment duration of 2 cycles, 2/5 untreated MDS/CMML pts achieved CR/CRi; 1 HMA rel/ref AML had CR; 1 untreated AML pt each had PR and MLFS. 90% of pts have not progressed. Updated results will be presented at the ASH 2015 meeting; by then all 29 pts will have completed a minimum of 4-6 cycles on study and full efficacy and AE result on all pts will be reported. To date the OS at 6 mo is 77% (95% CI: 44-97%) with a median PFS of 4 mo (range: 2-NR). Many pts in the untreated cohorts have just enrolled. Conclusion: Hh pathway inhibition with the clinically well tolerated SMO inhibitor Sonidegib in combination with Aza in MDS and AML pts is well tolerated with mostly hematologic AEs as expected with early signs of clinical activity in untreated and HMA-failure pts. Full efficacy results of 29 pts and updated safety data will be reported for this first combination trial of a SMO inhibitor in combination with a HMA in MDS and AML pts. Disclosures Mesa: Gilead: Research Funding; Novartis Pharmaceuticals Corporation: Consultancy; Incyte Corporation: Research Funding; Genentech: Research Funding; Pfizer: Research Funding; Promedior: Research Funding; NS Pharma: Research Funding; CTI Biopharma: Research Funding. Al-Kali:Novartis: Research Funding.