Citations

Abstract Classical Hodgkin lymphomas (cHLs) include infrequent malignant Hodgkin Reed-Sternberg (HRS) cells within an extensive but ineffective inflammatory/immune cell infiltrate. HRS cells exhibit frequent copy number alterations (CNAs) of 9p24.1/CD274 (PD-L1)/PDCD1LG2(PD-L2), ranging from low-level polysomy to relative copy gain and high-level amplification, all associated with increased expression of programmed death receptor-1 (PD-1) ligands on the tumor cell. PD-1 ligands engage the PD-1 receptor on T cells, inhibiting T cell activation and anti-tumor immune responses. cHL patients (pts) with the highest-level 9p24.1 alterations, PD-L1/PD-L2 amplification, have inferior progression-free survival (PFS) after standard primary chemotherapy (Roemer et al. J Clin Oncol 2016). Given the demonstrated responsiveness of cHL to PD-1 blockade, we examined the prevalence and type of 9p24.1 genetic alterations, PD-L1 expression, and association of these alterations with clinical outcome in pts receiving nivolumab (nivo; anti-PD-1) for relapsed/refractory (R/R) cHL. CheckMate205 is a multicenter, multicohort, phase 2 trial of nivo in R/R cHL. This analysis focused on 2 cohorts: pts with recurrent cHL following autologous stem cell transplantation (ASCT) and subsequent brentuximab vedotin (BV) (cohort B), and pts with R/R cHL following ASCT and BV given pre- or post-ASCT (cohort C). Pts received nivo 3 mg/kg every 2 weeks. Best overall response (BOR) and PFS were assessed by an independent radiological review committee (IRRC). In pts with available tumor biopsies, 9p24.1 genetic alterations were evaluated via fluorescence in situ hybridization (FISH) assay; probes encompassed CD274 (PD-L1, red) or PDCD1LG2 (PD-L2, green)and included a centromeric control (aqua).Dual immunohistochemical staining of PD-L1/PAX5 was performed to delineate PD-L1 expression in PAX5dim+ HRS cells and PAX5- cells in the tumor microenvironment. A modified PD-L1 H-score (range 0-300) was calculated by multiplying the percentage of PAX5+ (malignant) or PAX5- (non-malignant) cells with positive staining (0-100%) and the average intensity of positive staining (1-3+; ≥50 RS cells counted). All p-values are nominal. 96 pts had evaluable baseline tumor biopsy specimens; all 96 had detectable 9p24.1 alterations: polysomy in 10/96 (10%), copy gain in 56/96 (58%), amplification in 28/96 (29%), and presumptive rearrangement (split-apart FISH signal) in 2/96 (2%) (Figure). There was a significant association between PD-L1 protein expression (H-score) and the level of 9p24.1 alterations in HRS cells (p=0.002) (Figure). We next evaluated the association between BOR and defined 9p24.1 alterations and PD-L1 H-scores. The level of 9p24.1 CNAs was significantly associated with BOR (p=0.01); no pts with progressive disease (PD) had genomic amplification and no pts with complete response (CR) had polysomy. Similarly, there was significant association between PD-L1 H-score in HRS cells and BOR (p=0.02); all pts with PD had PD-L1 H-scores in quartiles (Q) 1/2, whereas most pts with CR had PD-L1 H-scores in Q4. We also assessed the association of PFS with 9p24.1 status and PD-L1 H-scores. The level of 9p24.1 alterations was associated with PFS; pts with 9p24.1 amplification had the most favorable PFS with nivo. HRS cell PD-L1 H-score (by quartiles) was also significantly associated with PFS (p=0.048), as pts with PD-L1 H-scores in Q1/Q2 had significantly shorter PFS than those with scores in Q3/Q4 (p=0.01). In contrast, there was no association between PD-L1 expression on non-malignant cells in the tumor microenvironment and PFS (p=0.43). In conclusion, all evaluable pts in this study had genetic alterations of 9p24.1/PD-L1/PD-L2 and copy number-dependent increased expression of PD-L1 in HRS cells. Although high-level alterations of 9p24.1 and increased PD-L1 expression were previously linked with inferior response to standard primary chemotherapy, we now associate these parameters with more favorable outcomes to targeted PD-1 blockade. These analyses also highlight the importance of quantifying and delineating PD-L1 expression in HRS cells and non-malignant cells in the tumor microenvironment in cHL biopsy evaluation. While further research is needed to guide possible use in clinical practice, these data advance understanding of 9p24.1 alterations and PD-L1 expression as prognostic biomarkers in cHL. Disclosures Engert: Takeda, BMS: Consultancy, Honoraria, Research Funding. Zinzani:Abbvie: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees; MorphoSys: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees; Celegene: Membership on an entity's Board of Directors or advisory committees; Roche: Membership on an entity's Board of Directors or advisory committees. Timmerman:Bristol-Myers Squibb, Kite Pharma, Valor Biopharmaceuticals, Janssen: Research Funding; Seattle Genetics, Genmab, Celgene: Consultancy, Honoraria. Ansell:BMS, Seattle Genetics, Merck, Celldex and Affimed: Research Funding. Armand:Bristol-Myers Squibb: Consultancy, Research Funding; Pfizer: Research Funding; Sequenta Inc: Research Funding; Roche: Research Funding; Merck: Consultancy, Research Funding; Infinity Pharmaceuticals: Consultancy. Kuruvilla:BMS: Consultancy, Honoraria; Abbvie: Consultancy, Honoraria; Gilead: Consultancy, Honoraria; Amgen: Honoraria; Celgene: Consultancy, Honoraria; Merck: Honoraria; Roche Canada: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria; Seattle Genetics: Consultancy, Honoraria; Lundbeck: Honoraria. Cohen:Bristol-Myers Squibb: Research Funding; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees; Seattle Genetics: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Millennium/Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Pharmacyclics: Consultancy, Membership on an entity's Board of Directors or advisory committees; Infinity: Consultancy, Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding. Collins:Takeda: Consultancy, Honoraria, Speakers Bureau. Trneny:Roche, Celgene, Takeda, Janssen, Gilead, Bristol-Myers Squibb: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Roche, Celgene: Research Funding. Farsaci:Bristol-Myers Squibb: Employment. Kato:Bristol-Myers Squibb: Employment. Sumbul:Bristol-Myers Squibb: Employment. Rodig:Bristol-Myers Squibb: Honoraria, Research Funding; Perkin Elmer: Membership on an entity's Board of Directors or advisory committees. Shipp:Bayer: Research Funding; Merck, Gilead, Takeda: Other: Scientific Advisory Board; Cell Signaling: Honoraria; Bristol-Myers Squibb: Consultancy, Research Funding.

Abstract Abstract 5060 Background: The Myeloproliferative Neoplasm Symptom Assessment Form (MPN-SAF) is a concise instrument of patient reported outcomes (PRO) designed to assess the unique spectrum of symptoms present in the majority of patients (Mesa et. al. Cancer 2007). We sought to validate the Italian Translation of the MPN-SAF which addresses 19 separate symptoms reported by MPN patients. Methods: Translation: We utilized the standard practice of PRO translation in which 3 independent translations are created by 3 independent translators fluent in both languages. A fourth translator then discussed the translations with the other translators and a consensus translation was obtained. Validation: Patients self completed the MPN-SAF: Italian at the time of a physician office visit and the Italian EORTC-QLQ-C30 (a widely used instrument of PRO for cancer patients) was co-administered for validation purposes. Results: Patients and Symptomatic Burden: 186 patients were prospectively enrolled (ET (N=88; 47%), PV (N=69; 37%) and MF (N=29; 16%)) a median of 6 years (range:0-29) from their diagnosis. Patients were of a median age (62; range 29–91 years) and gender (56% females) typical of the disease. 72% (N=135) had received some form of non-aspirin medical therapy for their disease, and 68% were on therapy at the time of completing the questionnaire. Patients frequently had a history of either thrombotic events (31%) and/or hemorrhagic events (13%). The MPN-SAF measured 19 items in the enrolled patients (data summarized in Table 1). Validation Analysis: EORTC-QLQ-C30: Consistent with our experience with the MPN-SAF:English, Pearson correlations between MPN-SAF:Italian individual symptom scores and the Italian EORTC-QLQ C30 showed excellent correlations with co-validation questions including fatigue, pain, insomnia, (all p<0.001). Excellent correlations were demonstrated between EORTC-QLQ-C30 subscales and corresponding MPN-SAF measurements. Comparison with MPN-SAF:English: Comparison with 102 patients prospectively completing the MPN-SAF: English (ET=20, PV=23, MF=59) in the USA indicated very strong correlations (when controlling for MPN subtype) in the prevalence of all 19 items assessed and only subtle differences in terms of symptomatic severity for fatigue, itching and insomnia. Conclusions: The MPN-SAF:Italian is an easy to administer, clear, 19-item inventory of patient-reported outcomes that is specific to MPNs. Additionally, the instrument is validated by 1) comparison to previously validated Italian instruments and 2) the correlation with the MPN-SAF:English. Utilization of the instrument in Italian MPN clinical trials will allow for useful comparison to patients completing the MPN-SAF in other countries and will serve as a valuable clinical marker of disease symptom severity. Disclosures: Vannucchi: Novartis: Membership on an entity's Board of Directors or advisory committees. Mesa:SBio: Research Funding; Novartis: Research Funding; Celgene: Research Funding; Incyte: Research Funding; Roche: Research Funding; eisai: Research Funding; telik: Research Funding.

Abstract Abstract 457 Introduction- The 2008 World Health Organization (WHO) diagnostic criteria for myeloproliferative neoplasms (MPN) underscore the role of bone marrow (BM) morphology in distinguishing essential thrombocythemia (ET) from early, and at times prefibrotic, primary myelofibrosis (PMF) that clinically presents like ET. The value of such a distinction in predicting clinical outcome has been questioned by some investigators. Study Design- Clinician scientists and hematopathologists from seven international centers of excellence for ET convened to design a clinicopathologic database of patients locally diagnosed and treated as ET. Study eligibility criteria included availability of treatment-naïve BM specimens obtained within one year of diagnosis. All bone marrows subsequently underwent a central blinded re-review by the author of the pertinent WHO chapter (JT) who applied strict WHO guidelines to identify cases of early PMF that were spuriously diagnosed as ET. Results- Revision of the BM biopsies according to the WHO morphological criteria confirmed ET in 891 patients (81%). Diagnosis was revised to early, prefibrotic PMF in 180 patients (16%). The remaining 33 (3%) BM specimens were qualitatively inadequate for accurate classification or represented unclassified cases. i) At presentation, early PMF, as opposed to true ET, was characterized by higher leukocyte (p<0.0001) and platelet (p=0.002) counts, lower hemoglobin (p=0.01) and hematocrit (p=0.001) levels, higher serum lactate dehydrogenase level (p<0.0001), higher circulating CD34+ cell count (p=0.03) and higher rate of palpable splenomegaly. JAK2V617F mutational frequency was 60% in each of the two groups. ii) Median follow-up was 6.2 years for ET and 7.0 years for early PMF. During this period, the rates of arterial (1.2-1.4% patients/year) and venous (0.6 patients/year) thrombotic complications were similar in the two groups. However, patients with early PMF, as compared to those with ET, were more likely to develop overt myelofibrosis (1% vs. 0.5% patients/year; RR=2.0, p=0.04) or acute leukemia (0.6% vs. 0.1% patients/year; RR=5.2, p=0.001). Cumulative leukemic transformation rate at 10 and 15 years was 0.7% and 2.1% in true ET versus 5.8% and 11.7% in PMF Similarly, survival was significantly worse in patients with early PMF (mortality rate: 2.7% vs. 1.3% patients/year; RR=2.1, p=0.002).The 10 and 15-years overall survival rates were: 89% and 80% in true ET versus 76% and 59% in PMF. On multivariable analysis, other risk factors for poor survival were age > 60 years (HR=6.3, p<0.0001), a leukocyte count of > 11×109/L (HR=2.13, p<0.0001) and history of thrombosis (HR=3.0, p<0.0001). Conclusions- The current study validates the clinical relevance of strict adherence to WHO criteria in the diagnosis of ET and provides seminal information on the survival and risk of leukemic transformation in strictly WHO-defined ET, which appears to be substantially better than previously assumed. Disclosures: No relevant conflicts of interest to declare.

Abstract Abstract 4095 Background: Symptomatic burden in myeloproliferative neoplasms (MPNs) is present in over 70% of MPN patients (Mesa et. al. Cancer 2007). We sought to validate a broadly applicable instrument (MPN-SAF) to assess symptoms in myelofibrosis (MF), essential thrombocythemia (ET) and polycythemia vera (PV). Methods: Using the previously validated MF-SAF as a base instrument, we added several key additional symptoms previously identified as present in all subtypes of MPNs including headaches, concentration, dizziness, extremity tingling, insomnia, sexual problems and mood changes on a 0 (absent) to 10 (worst-imaginable) scale. Validation: The MPN-SAF was administered jointly with the EORTC-QLQ-C30 as the co-validation instrument using prospective cohorts in the USA, Sweden and Italy. The translated MPN-SAF (Swedish and Italian) was created through a standard approach using teams of 4 translators working in concert. Results: Compiled MPN-SAF: Patient data: 402 MPN-SAF surveys were administered (English (25%), Italian (46%) and Swedish (28%)) in 161 ET patients (40%), 145 PV patients (36%), and 96 MF patients (24%), an average of 7.8 years (range 0 – 43 years) from their MPN diagnosis. Participants were of typical age (64.9, range 26 – 91 years) and gender (53% female) characteristic of disease. Prior hemorrhage (10%) and thrombosis (25%) were frequent. 68% of patients currently received cytoreductive therapy and 84% received cytoreductive therapy in the past. Patients and Symptomatic Burden: 19 items assessed in the MPN-SAF demonstrated consistently that the most common symptoms were fatigue (93%), decreased quality of life (84%), insomnia (65%), sad mood (65%), and sexuality problems (58%). The least common symptoms (<50% prevalence) were fevers (20%), weight loss (35%), abdominal pain (46%), cough (46%), headache (48%), and bone pain (49%). Symptoms were most severe in MF, followed by PV, then ET patients. Although symptoms are present in all 3 MPN subgroups, itching is notably more burdensome in PV patients (65%, median score of 2.8 out of 10). Additionally, abdominal pain, abdominal discomfort, early satiety and inactivity all are most prevalent and severe in MF. Interestingly, night sweats (present in 56%) overall had similar prevalence and severity across all 3 MPNs. The majority found the MPN-SAF easy to understand (98%) and “addressed most of my MPN symptoms” (96%). Comparison to EORTC-QLQ-C30: Strong correlations existed between individual items represented on both the MPN-SAF and the EORTC-QLQC30 including pain, fatigue, appetite and insomnia (all p<0.001). Additionally key symptomatic elements were highly correlated with the EORTC QLQ-C30 functional subscales. Comparison to Physician Perceptions: Comparison of the results of the MPN-SAF to enrolling physicians' blinded opinion of patients symptoms (6 assessed - night sweats, fevers, fatigue, weight loss, bone pain, and pruritus) showed excellent correlation with corresponding patients' responses except bone pain (all p<0.001). Comparison across Countries: When controlling for MPN subtype, responses between the three different countries (and 3 different languages the MPN-SAF was administered) demonstrated great consistency and correlation for all but 1 item, bone pain. Serial MPN-SAF Results: 51 patients in the USA (ET (17.6%), PV (25.5%), and MF (56.9%)), responded to a repeat MPN-SAF survey sent via US mail (50% response rate, mean time between surveys 190±63 days (range 43 – 257)). Pearson correlations indicate that most MPN-SAF items are well correlated (r >0.5, p<.001) upon repeat survey administration. Items characteristic of advanced disease, including weight loss, fever, and cough displayed lower Pearson correlations (r=0.46, -0.08, and 0.38 respectively). Intra-class correlations for test-retest reliability indicated that common features of disease, including mean BFI, inactivity, insomnia, and night sweats, were highly reproducible upon serial survey administration (ICC>0.7, 2, k model used). Conclusion: The MPN-SAF is comprehensive and reliable instrument which is available in multiple languages to evaluate MPN-associated symptoms. The MPN-SAF is recommended as a uniform symptom assessment tool for MPN patients participating in clinical trials globally. Disclosures: Vannucchi: Novartis: Consultancy. Samuelsson:Roche Sweden:. Harrison:Incyte: Honoraria; Novartis: Honoraria. Mesa:SBio: Research Funding; Novartis: Research Funding; Celgene: Research Funding; Incyte: Research Funding; Roche: Research Funding; eisai: Research Funding; telik: Research Funding.

Abstract Background and purpose of the study: Several reports have documented that histone deacetylase inhibitors induce neoplastic cells to undergo growth arrest, differentiation and/or apoptotic cell death. Among these agents, Givinostat inhibits proliferation of cells bearing the JAK2V617F mutation and has shown clinical significant activity with good tolerability in patients with chronic myeloproliferative neoplasms, including polycythemia vera (PV). In two phase II studies [Rambaldi et al. Br J Haematol 2010;150:446, Finazzi et al. Br J Haematol 2013;161:688] the maximum administered dose (150 mg/day) was generally well tolerated. Assuming a linear relationship between dose and efficacy, greater clinical efficacy could be expected with increased doses of Givinostat. Methods: This is a two-part, multicenter, open label, non-randomized, phase Ib/II study to assess the safety and tolerability, maximum tolerated dose (MTD) and preliminary efficacy of Givinostat in patients with JAK2V617F positive PV. Part A (i.e. phase Ib) is the dose escalation portion of the study, while Part B assesses the preliminary clinical efficacy of Givinostat at the MTD defined in Part A. Eligible patients for this study include JAK2V617F positive PV patients, who have active and/or uncontrolled disease, defined as: (i) Hematocrit (HCT) ≥ 45% or HCT <45% normalized by phlebotomy, and (ii) PLT > 400 x109/L, and (iii) WBC > 10 x109/L. Study therapy is administered in 28 day cycles (cycle is defined as 4 weeks of treatment). Disease response has been evaluated according to the clinico-haematological European LeukemiaNet (ELN) criteria [Barosi et al. Blood 2009;113:4829] at Cycles 3 and 6. Disease-related symptoms have been reported directly by the patients who completed the MPN-SAF QoL form. The study lasts up to a maximum of 24 weeks of treatment. However, after completion of the trial, all patients achieving clinical benefit are allowed to continue treatment with Givinostat in a long-term study (ClinicalTrials.gov ID: NCT01761968). In Part A, the Cycle 1 has been used to define the MTD of Givinostat. Only dose limiting toxicities (DLTs) experienced during Cycle 1 were considered for dose escalation decisions. Part B is the cohort expansion part of the study to assess the preliminary clinical efficacy of Givinostat at the MTD in evaluable patients Results: In Part A, 12 patients with active and/or uncontrolled disease, were treated with Givinostat, 6 patients at DL1 (100 mg b.i.d.), 3 patient at DL6 (150 mg/die) and 3 patients at DL0 (50 mg b.i.d.). Only one DLT .(grade 3 dyspepsia) was observed in the 6 patients treated at DL1 during the Cycle 1. Givinostat treatment was generally well tolerated: one patient developed grade 4 and two patients grade 3 thrombocytopenias at DL1 after the Cycle 1. Complete/partial response was observed in 100% of evaluable patients at Cycle 3 (Figure). At that time, an important reduction of WBC and PLT count (about 50% in both cases), an HCT control without phlebotomy, a net decrease of MPN-SAF total score and JAK2V617F allele burden (about 50% and 30%, respectively) have been noted and generally maintained at Cycle 6. One out of 3 (33%) patients with splenomegaly at baseline normalized the spleen at Cycle 6. PK/PD evaluations are currently under analysis. Part B started on December 2015 and is currently recruiting patients. At the time of ASH Meeting, a presentation of the preliminary results of the interim analysis (IA) is planned. The objective of this IA is to evaluate the response rate of the first 12 treated and evaluable patients. Conclusions: Taking into account the continuous schedule of the drug as prescribed in this current study, the daily dosage of 200 mg has been identified as the MTD of Givinostat in PV patients. Givinostat treatment is generally well tolerated and shows preliminary clinical efficacy in PV patients with an active/uncontrolled disease. Response rate of patients in Part A C3D28 = Cycle 3 Day 28, or three months of treatment. C6D28 = Cycle 6 Day 28, or six months of treatment. Two patients dropped-out the study Part A, due to Informed Consent Form withdrawal, while 1 patient left the study for AE (i.e. grade 3 dyspepsia, DLT). At C3D28, 1 Complete Response (CR) and 8 Partial Response (PR) have been observed. At C6D28, 1 Complete Response (CR), 7 Partial Response (PR) and 1 No Response (NR) have been observed Figure Figure. Disclosures McMullin: Novartis: Honoraria, Speakers Bureau. Vannucchi:Novartis: Honoraria, Speakers Bureau. Mesa:Ariad: Consultancy; CTI: Research Funding; Galena: Consultancy; Celgene: Research Funding; Promedior: Research Funding; Novartis: Consultancy; Incyte Corporation: Research Funding; Gilead: Research Funding. Tibes:Italfarmaco S.p.A.: Consultancy, Honoraria. Bettica:Italfarmaco S.p.A.: Employment. DI Tollo:Italfarmaco S.p.A.: Employment.

Abstract Background: Over the last two decades several phenotypic, molecular, and chromosomal markers have been identified that are significantly associated with the prognosis of CLL patients. Therefore, clinicians managing CLL patients would benefit from a simplified prognostic index. Methods: We analyzed prospectively collected data from 337 Binet A CLL patients enrolled in Italian the O-CLL1-GISL protocol with the aim of developing scores capable of predicting treatment free survival (TFS). Factors independently associated with TFS were included in the prognostic indexes. To account for differences in the magnitude of the association between the individual independent factors and TFS, we assigned a weighted risk score to each factor based on ranges of their corresponding hazard ratios (HRs) (i.e., 1 point for HR 1.1-1.9; 2 points for HR 2.0-2.9, etc.). The total risk score was then calculated by the sum of the ratings of each factor on individual basis. Risk groups were identified combining risk categories with a non-statistically different TFS. Results: We developed two scores based on weighted multivariable models: the first included clinical and laboratory parameters [clinical score (c-score)], while the second was based on biological markers [biological score (b-score)] (Table 1). The c-score allowed to predict the TFS of patients through the combination of Rai stage, b2-microglobulin and absolute lymphocyte count (ALC), while the b-score predicted TFS by IGHV mutational status and CD38 expression. The c-score showed a C-statistic of 0.72, while the b-score was 0.67, although cases stratified according to the b-score showed a more specific mRNA/microRNA profile. When the two scores were forced in a multivariate analysis, both showed an independent predictive value on TFS with a similar HR, demonstrating their complementarity. Thus, we attempted to integrate the two scores performing a further multivariate analysis in which all parameters, significantly associated with TFS at univariate analysis, were tested (Table 1). ALC, Rai stage, b2-microglobulin together with IGHV mutational status, resulted independently associated with TFS. We constructed a weighted score [comprehensive score (co-score)], including all the above 4 variables, which allowed the identification of 3 different risk groups with significantly different TFS (Figure 1). The C-statistic of the g-score was 0.75, showing a better concordance than the other two scores. Moreover, its validity was externally validated in a series of 297 newly diagnosed Binet A CLL patients from the Mayo Clinic, USA. Conclusions: Using this multistep process and external validation, we developed a score with high discriminatory power and predictive significance on the individual patient level. Table 1. Univariate and multivariate Cox proportional Hazards Models Variable Univariate analysis Multivariate analysis Clinical model Biological model Comprehensive model HR (95% CI) P HR (95% CI) P score HR (95% CI) P score HR (95% CI) P score Age (years) <60/>60 1.12 (0.73-1.74) 0.59 - - - - - - - - - Sex Male/Female 0.93 (0.6-1.44) 0.93 - - - - - - - - - Rai stage 0/I-II 2.30 (1.47-3.50) <0.0001 2.13 (1.24-3.03) 0.004 0/2 - - - 1.76 (1.11-2.78) 0.015 0/1 ALC (109/L) <10/>10 3.43 (1.99-5.92) <0.0001 2.91 (1.85-5.20) <0.0001 0/2 - - - 2.70 (1.54-4.72) 0.001 0/2 b-2 microglobulin normal/elevated 3.04 (1.96-4.70) <0.0001 2.78 (1.79-4.30) <0.0001 0/2 - - - 2.65 (1.66-4.21) <0.0001 0/2 LDH normal/elevated 1.25 (0.57-2.71) 0.57 - - - - - - - - - CD38 negative/positive 3.22 (2.06-5.02) <0.0001 - - - 2.11 (1.15-3.16) 0.02 0/2 1.40 (0.80-2.42) 0.24 - ZAP-70 negative/positive 2.34 (1.51-3.61) <0.0001 - - - 1.21 (0.70-2.16) 0.485 - 1.0 (0.98-1.01) 0.72 - IGHV mutated/unmutated 3.57 (2.32-5.50) <0.0001 - - - 2.10 (1.12-3.90) 0.019 0/2 2.39 (1.27-4.50) 0.007 0/2 FISH risk low+int/high 2.93 (1.46-5.90) 0.002 - - - 1.65 (0.76-3.34) 0.216 - 1.80 (0.84-3.88) 0.13 - Abbreviations: ALC: absolute lymphocyte count; CI: confidential interval; HR: hazard ratio. Figure 1. TFS according to comprehensive progression risk score. Figure 1. TFS according to comprehensive progression risk score. Disclosures Shanafelt: Cephalon: Research Funding; Glaxo-Smith-Kline: Research Funding; Genentech: Research Funding; Hospira: Research Funding; Celgene: Research Funding; Jannsen: Research Funding; Polyphenon E International: Research Funding; Pharmacyclics: Research Funding. Kay: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; Hospira: Research Funding; Tolero Pharma: Research Funding; Pharmacyclics: Research Funding.

Abstract Abstract 1904 Poster Board I-927 BACKGROUND: Pomalidomide is an IMiDsó immunomodulatory drug that was created by chemical modification of thalidomide with the intent to reduce toxicity and enhance therapeutic activity. In a phase-2 randomized study of patients with myelofibrosis (MF), treatment with pomalidomide alone or in combination with a short course of prednisone was shown to be well tolerated and active in alleviating anemia ( JCO 2009). Herein, we report observations during the longer-term follow-up of those patients who had responded to a pomalidomide-containing treatment regimen. METHODS: Both primary and post polycythemia vera/essential thrombocythemia MF were included in the current study. Protocol eligibility criteria included absolute neutrophil count of × 109/L, platelet count of 50 × 109/L and hemoglobin level of < 10 g/dL. Patients with prior thalidomide or lenalidomide therapy were excluded from study participation. Response was assessed by the International Working Group for Myelofibrosis Research and Treatment criteria (IWG-MRT) (Blood. 2006). Pomalidomide was administered daily and continued indefinitely in responding patients. Prednisone was given for the first 3 months only, in a tapering dose schedule, starting at 30 mg/day. RESULTS: A total of 84 patients were enrolled from April 2007 through May 2008 and received treatment with pomalidomide alone 2 mg/day (n=22), pomalidomide 2 mg/day + prednisone (n=19), pomalidomide 0.5 mg/day + prednisone (n=22) or prednisone alone (n=21). Short-term toxicity details have previously been published (Tefferi et al. JCO 2009) and were remarkable for the lack of neuropathy and low prevalence of grade 3 or 4 myelosuppression (5–16%). Based on an intent-to-treat analysis, 16 (25%) of the 63 patients receiving pomalidomide alone or with a 3-month course of prednisone responded at a median of 1.8 months (range 0.9–6.9) from treatment initiation; all responses represented improvement in anemia with little or no effect on splenomegaly. Specifically, 12 of the 16 treatment responders became transfusion independent and the remaining 4 had a hemoglobin increase of > 2 g/dL (median best hemoglobin response = 11.9 g/dL; range 8.5–15.9). Responding patients usually displayed increases in platelet count but there was no consistent change in serum lactate dehydrogenase level. As of August 2009, ten (63%) of the 16 treatment responders were still in anemia remission and receiving pomalidomide therapy; median time on treatment was 19 months (range, 14–26) and median response duration was 17 months (range, 13-24). No new side effects emerged during this period. Six patients discontinued treatment because of either loss of response (n=5) or progressive splenomegaly/leukocytosis (n=1); 3 patients with continued anemia remission have had substantial increases in their spleen size, which qualifies as spleen progression per IWG-MRT. Among 9 patients with available cytogenetic information, all 3 with unfavorable karyotype relapsed while none of the 6 with favorable karyotype did. A small number of patients (n=7) had follow-up bone marrow examination at 1 to 2 years, at the discretion of their treating physician; none of these patients displayed any change in bone marrow fibrosis or JAK2V617F mutational status. Suppression of a monosomy 7 clone was documented in two patients. In one, the percentage of abnormal metaphases decreased from 90% to 15% after 11 months of treatment with pomalidomide but increased back to 100% four months later, when the patient relapsed while still on treatment. In the second patient, the percentage of abnormal metaphases was 65% at baseline, remained at 75% after 10 months of pomalidomide therapy, but decreased to 7% after one month of treatment discontinuation for relapse; a repeat examination in this patient after another 3 months (still off therapy) showed monosomy 7 and new additional abnormalities (including 4q21q25 deletion) in 65% of metaphases evaluated. CONCLUSION: Longer-term follow-up of pomalidomide-treated patients with myelofibrosis confirm the drug's favorable side effect profile. Also, the majority of treatment responders maintain their remission, which is exclusively anemia remission, for at least one year and several remain in remission after 2 years of therapy. The drug has limited effect on splenomegaly and progressive splenomegaly might occur in some patients despite continued remission in anemia. The presence of unfavorable cytogenetic abnormalities predicts relapse. Disclosures: Gale: Celgene: Employment.

Abstract Background In the recent International Prognostic Score for Thrombosis in essential thrombocythemia (IPSET-thrombosis), age and history of thrombosis were confirmed as independent risk factors for future thrombosis and the study also identified independent prothrombotic role for cardiovascular (CV) risk factors and JAK2 V617F mutation (Barbui et al. Blood 2012). Methods In the current study, we re-analyzed the original IPSET-thrombosis data in 1019 patients with WHO-defined ET in whom JAK2 mutational status was available, in order to quantify the individual contributions of JAK2 mutations and CV risk factors in conventionally-assigned low and high risk ET, as well as in age- versus thrombosis-defined high risk status. Results After a median follow-up of 6.8 and 5.0 years in conventionally-assigned low- and high-risk patients, respectively, the overall annual rate of total thrombosis (108 events) in conventionally-assigned low- and high-risk patients was 1.11%-pt/y (CI 0.81-1.52) and 2.46%-pt/y (CI 1.94-3.11) respectively (p=0.001), and the difference was mainly due to a higher frequency of arterial thrombosis in high-risk patients (p<0.001).The influence of JAK2 mutational status and CV-risk factors on the rate of thrombosis in conventionally assigned low- and high-risk groups is presented in the table. Table 1. Additional risk factors N (%) Event Rate % pts/yr (95% CI) P-value P-value P-value trend Low risk 506 (50) 39 1.11 (0.81-1.52) None 200 (40) 7 0.44 (0.21-0.92) ref Cardiovascular risk factor 36 (7) 3 1.05 (0.34-3.25) 0.220 0.227 JAK2V617F 213 (43) 21 1.59 (1.04-2.44) 0.001 0.217 Both 52 (10) 8 2.57 (1.29-5.15) <0.001 ref <0.001 High risk 513 (50) 69 2.46 (1.94-3.11) None 111 (22) 10 1.44 (0.78-2.68) ref Cardiovascular risk factor 44 (9) 4 1.64 (0.62-4.37) 0.909 0.067 JAK2V617F 222 (43) 30 2.36 (1.65-3.38) 0.168 0.082 Both 136 (27) 25 4.17 (2.82-6.17) 0.011 ref 0.005 The number of major arterial and venous thrombosis was reported as rates per 100 patient-years and the difference among groups was assessed by Mantel Cox log-rank test i) Conventionally-assigned low-risk group. Amongst 506 patients, 200 (40%) displayed neither JAK2 mutation nor CV risk factors and their annual rate of thrombosis was 0.44%, as opposed to 1.05% in the presence of CV risk factors (P=NS), 1.59% in the presence of JAK2 mutation (p=0.001) and 2.57% in the presence of both CV risk factors and JAK2 mutation (P<0.001). There was no significant difference when low-risk patients with both JAK2 mutation and CV risk factors were compared with either those with CV risk factors only (p=0.227) or those with JAK2 mutation only (p=0.217). ii) Conventionally assigned high-risk group: The absence or presence of one or both of the aforementioned additional risk factors for thrombosis were documented in 111 (22%), 44 (9%), 222 (43%) and 136 (27%) patients, respectively, with corresponding annual rates of thrombosis at 1.44%, 1.64%, 2.36% and 4.17% (Table). High-risk patients with both risk factors had a significantly higher risk of thrombosis compared to their counterparts with the absence of JAK2 mutations and CV risk factors (p=0.011). Additional analysis revealed limited enhancement of thrombosis risk by either JAK2 mutations or CV risk factors or both in patients whose high-risk status was defined by the presence of thrombosis history, regardless of age (P=NS). In contrast, the presence of JAK2 mutations, with or without CV risk factors, might have affected thrombosis risk in patients where high-risk status was defined by age alone (p=0.05). Conclusions The current study suggests the possibility of considering four risk categories in ET: "very low risk" group (age ≤60 years and without thrombosis history, JAK2 mutations or CV risk factors); "low risk" (age ≤60 years and without thrombosis history but with JAK2 mutations or CV risk factors); "intermediate risk" (age>60 years but without thrombosis history or JAK2 mutations); and "high risk" (thrombosis history at any age or JAK2 -mutated patients who are older than 60 years of age). Treatment recommendations for each one of the above-mentioned new risk categories should be examined in the context of prospective controlled studies. Disclosures Barbui: Novartis: Speakers Bureau. Vannucchi:Novartis Pharmaceuticals Corporation: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Shire: Speakers Bureau; Baxalta: Membership on an entity's Board of Directors or advisory committees. Buxhofer-Ausch:AOP Orphan: Research Funding. De Stefano:Novartis: Research Funding, Speakers Bureau; Janssen Cilag: Research Funding; Shire: Speakers Bureau; GlaxoSmithKline: Speakers Bureau; Bruno Farmaceutici: Research Funding; Roche: Research Funding; Amgen: Speakers Bureau; Celgene: Speakers Bureau. Gisslinger:Janssen Cilag: Honoraria, Speakers Bureau; AOP ORPHAN: Consultancy, Honoraria, Research Funding, Speakers Bureau; Geron: Consultancy; Sanofi Aventis: Consultancy; Celgene: Consultancy, Honoraria, Research Funding, Speakers Bureau; Novartis: Honoraria, Research Funding, Speakers Bureau.

Abstract Abstract 1909 Poster Board I-932 Background: The International Prognostic Scoring System (IPSS) for primary myelofibrosis (PMF) utilizes five independent predictors of inferior survival; of these, a hemoglobin level <10 g/dL has the highest impact on survival (Cervantes et al. Blood 2009;113:2895). In the current study, we examined the additional prognostic impact of transfusion need at diagnosis or becoming transfusion-dependent in the first year of diagnosis. These events were also correlated with JAK2 or TET2 mutational status. Methods: Patients were selected from the Mayo Clinic PMF database based on availability of bone marrow histology and IPSS-relevant information at diagnosis and follow-up transfusion history at one year from diagnosis. WHO criteria were used for PMF diagnosis. Patients who underwent allogeneic hematopoietic cell transplantation were censored at time of transplant. Patient records were updated in July, 2009. Survival curves were constructed using the Kaplan-Meier method and compared by the log-rank test. Multivariable survival was analysed using Cox regression model. Results: A consecutive cohort of 254 patients was studied (median age 59 years; range 28-87; 159 males). IPSS risk category was low, intermediate (int)-1, int-2 and high in 75, 71, 62 and 46 patients, respectively. JAK2V617F was present in 118 (62%) of 192 patients and TET2 mutations in 6 (13%) of 45 patients evaluated. Transfusion need at diagnosis was documented in 62 patients whereas an additional 22 patients became transfusion-dependent during the first year of their diagnosis. The remaining 170 patients remained transfusion-independent for at least one year post-diagnosis. To date, 139 patients have died. In patients who are alive, median follow-up was 5.3 years. Median survivals in IPSS high, Int-2, Int-1 and low risk patients were, 3, 3.9, 6.8 and 12.8 years, respectively (p<0.0001). Median survival for patients requiring transfusions at diagnosis was similar to that of patients who became transfusion-dependent in their first year of diagnosis, and both were significantly shorter than the median survival seen in patients who remained transfusion-free during the first year post-diagnosis: 2.9, 2.2 and 9.7 years, respectively (p<0.0001; figure). Multivariable analysis confirmed the IPSS-independent prognostic value of transfusion status-based risk stratification. Neither JAK2 nor TET2 mutational status correlated with transfusion need. Conclusions: In PMF, becoming transfusion-dependent in the first year of diagnosis is prognostically as detrimental as requiring transfusions at initial presentation. These events are not affected by JAK2 or TET2 mutational status and confer an IPSS-independent adverse prognosis. The ability to identify Int-1 risk patients with shortened survival (Figure) holds major treatment implications. Disclosures: No relevant conflicts of interest to declare.

Abstract Philadelphia-negative Myeloproliferative Neoplasms (MPN) include Polycythemia Vera (PV), Essential Thrombocythemia (ET) and Myelofibrosis Primary (PMF) and secondary to PV and ET (PPV-, PET-MF); included are also some less characterized entities defined as unclassified MPN (U-MPN). Risk of arterial and venous thrombosis is increased in MPN patients, and thrombosis is one of most important causes of mortality and morbidity. The risk of venous thrombosis in unusual sites, such as splanchnic vessels (SVT), is particularly associated with MPN; SVT can lead to complications such as portal hypertension, esophageal and gastric varices, ascites and hepatic failure. A recent meta-analysis reported that a MPN is the underlying cause of portal vein thrombosis in 31.5% and of Budd Chiari syndrome in 40.9% of cases (Smalberg, 2012). A significant association of SVT with JAK2V617F mutated MPN was reported (Dentali, 2009) but study of other correlations has been hampered by heterogeneity of available patient cohorts comprising relatively small number of cases. We conducted a retrospective multicenter study collecting clinical and biological data of patients (pts) with SVT associated with MPN diagnosed according to WHO2008 criteria, aiming to describe patients’ characteristics, trends and prognostic factors, and their potential implications for clinical practice. Data were collected from 15 international hematology centers in the framework of IWG-MRT. We collected 475 cases of pts with portal, splenic or mesenteric vein thrombosis (75.2%) or Budd Chiari syndrome (24.8%) associated with MPN. In 32% of cases, simultaneous involvement of portal (69.1% of total thrombosis), splenic (30.5%) and mesenteric (25.3%) veins occurred, and in 1.7% they were associated with Budd Chiari syndrome. Frequency of MPN subtype: 38.1% ET (n=181), 34.9% PV (n=166), 16.2% MF (n=77), 10.8% U-MPN (n=51). Median follow-up 87.9 mo (range 0.5-430); female 61.3% (n=292; P<0.0001 vs male); median age at MPN diagnosis (dg) 44.4 y (range 12-90), at SVT dg 44.9 y (range 17-85). In 229 cases (48%) MPN and SVT dg were coincident, while in 104 (22%) SVT occurred before MPN dg (median 40 mo, range 5-335) and in 129 (27%) during MPN follow up (median 79 mo, range 5-394). JAK2V617F mutational status is available for 361 pts: 99% PV, 84.7% ET, 88.1% PMF and 92.9% U-MPN pts were JAK2V617F positive, with a mean allele burden of 56±27.4%, 33.1±25.5%, 39.3±19.4% and 23.8±11.9%, respectively. Erythropoietin-independent colonies (EEC) were present at diagnosis in 80/110 evaluated cases (72.7%), 38/47 PV (84.4%), 32/45 ET (71.1%), 8/11 PMF (72.7%) and 2/7 U-MPN (28.6%). A concurrent thrombophilic state was found in 38.9% of cases. A 12.3% of pts experienced a recurrence of SVT after a median of 29 mo (range 1-378.3) and 35.8% developed thrombosis in other sites (17.7% arterial, 19.3% venous). Esophageal varices were found in 70.6% from which 31.9% bled. MF transformation occurred in 32/166 PV (19%) and in 23/181 ET (13%) pts, with median time to progression of 122.3 mo (range 5.4-377.3) and 125.1 mo (range 39.3-255.3), respectively. Evolution to acute leukemia (AL) occurred in 12 pts (2.7%), of which 2 PMF, 6 PV and 4 ET. In 3 PV and 1 ET pts a PPV and PET-MF transformation occurred before AL. After SVT, 77% of pts received anticoagulation, 23.5% antiaggregant therapy and 1.5% both; 68.8% received cytotoxic drugs, 11.4% of pts were treated with trans jugular porto-systemic shunt. No differences in survival were noted with these approaches. Beta blocker therapy was used in 48.5% of pts and correlated with improved survival (p=0.041) At last follow up 70/473 pts (14.8%) died; causes of death are evolution to AL (16.4%), other cancers (14.5%), disease progression without AL (12.7%), SVT (10.9%), hepatic failure and venous thrombosis other than SVT (9.1% each), heart failure and arterial thrombosis (7.3% each), hemorrhage (5.5%), renal failure and infection (3.6% each). After 10 y follow up 8/166 PV (5%), 14/181 ET (8%), 14/77 PMF (18%) and 1/51 U-MPN (1.96%) pts died (p<0.01). Survival was significantly affected by occurrence of thrombosis other than SVT (p<0.0001) but not recurrence in splanchnic vessels (p=0.068). This large study confirms the strong association between JAK2V617F-mutated MPN and SVT and identifies the category of U-MPN as the prognostically more favorable; thrombosis at sites outside the splanchnic vasculature remains the leading cause of death. Disclosures: No relevant conflicts of interest to declare.