Citations

Abstract Abstract 1744 Background: MF, ET and PV are BCR ABL negative myeloproliferative neoplasms (MPN). These are a subset of bone marrow disorders characterized by an overproduction of one or more types of blood or fiber cells in the bone marrow. There is disparate published data on the epidemiological estimates for these diseases in the EU. An evidence based synthesis of MPN epidemiology data can effectively inform population health care planning and economic decision support for these disorders. The aim of our study is to synthesize and provide a comprehensive review of epidemiology estimates from available sources including literature, publicly available registries as well as real world data. Methods: We conducted a search of literature published between 1995–2012 using terms related to MF, PV and ET. Elsevier and Medline databases were searched using Embase platform. Orphan disease registries, specific hematological malignancies registries, country specific databases and registries included RARECARE, Orphanet, Registry of hematological malignancies in France, UK Hematologic Malignancy research network. Finnish cancer registry and Sweden National registry were also evaluated. The RARECARE project is responsible for surveillance of rare cancers in Europe based on data from 88 cancer registries in 22 European countries and includes cancer cases diagnosed in 1995–2002. Orphanet provides an estimate of the prevalence of rare diseases in Europe based on a systematic survey of the literature. Calculation of prevalence in Orphanet is done by multiplying incidence with the mean duration of disease. UK THIN (∼5 million enrollees each year) general practitioner database was used to retrospectively identify patients with primary and secondary MF between 1/1/08 and 12/31/10. READ codes were used to identify MF. This database can track patients longitudinally over multiple years, are linked at the patient level by a unique identifier that is consistent across health related services and time and have been shown to be representative of the UK population. Results: Only six articles looking at the European population were retrieved through the literature. These articles as well as international/national reports were used to summarize epidemiological estimates for Myelofibrosis using several different terms. MF terminology varied among registries. Terms included “Primary myelofibrosis”, “myelosclerosis with myeloid metaplasia” and “myelofibrosis”. Annual prevalence of MF ranged from 0.5–9 cases per 100,000 individuals. For PV, even if terminology and coding is consistent, estimates still varied depending on registry used. RARECARE reported prevalence of 5.5 per 100,000 and Orphanet reported a range of 10–50 cases per 100,000. For ET, prevalence was reported only in RARECARE with 4.4 cases per 100,000 individuals. Prevalence estimates in UK were slightly higher compared to RARECARE; 0.9 cases per 100,000 for MF, 6 cases per 100,000 for PV and ET. Incidence for MF, PV and ET ranged from 0.3–1.9, 0.6–2.8, 0.5–2.2 per 100,000 patients respectively. Conclusions: Few publications and registries report epidemiology data for MF, PV or ET. Especially, prevalence data is very rare. There is wide variation in both prevalence and incidence estimates for MPN across EU data sources that can limit informed application of epidemiological research. The differences stem from lack of a unifying term for MF and coding differences coupled with limitations inherent in registry data including potential sources of bias, missing data, and issues with assessment of statistical significance. Additional research using standardized definitions/coding across appropriate real world databases and enhanced tumor registries are needed to add precision to or substantiate these results. Disclosures: Moulard: Sanofi: Employment, Equity Ownership. Mehta:Sanofi: Employment. Olivares:Sanofi: Employment, Equity Ownership. Iqbal:Sanofi: Employment, Equity Ownership. Mesa:Incyte: Research Funding; Lilly: Research Funding; Sanofi: Research Funding; NS Pharma: Research Funding; YM Bioscience: Research Funding.

Abstract Abstract 2837 Introduction: Treatment with the JAK2 selective inhibitor SAR302503 reduced spleen size, disease-related symptoms, and the JAK2 V617F allele burden, with an acceptable safety profile in patients with primary MF, post-PV MF, or post-ET MF in a Phase I/II study (J Clin Oncol 2011;29:789, ASH 2011; Abs 3838). The objective of this Phase II study is to assess the efficacy, safety, pharmacokinetics (PK), and pharmacodynamics (PD) of 3 doses of SAR302503. Methods: Patients with intermediate-2 or high-risk primary MF, post-PV MF, or post-ET MF were randomized to 1 of 3 dose groups of SAR302503 (300, 400, or 500 mg per day). Eligibility criteria included age ≥18 years, ECOG PS 0–2, and an enlarged spleen (length ≥5 cm). SAR302503 was taken orally, once a day, in consecutive 28-day cycles until disease progression or unacceptable toxicity. The primary endpoint is the absolute change in spleen volume at the end of cycle 3 assessed by MRI with independent central review. Secondary endpoints include spleen response (≥35% reduction in spleen volume vs baseline), safety, symptom response (MPN-SAF), PK, and PD (changes in leukocyte pSTAT3). Results: From August–December 2011, at total of 31 patients were enrolled (n=10 in the 300 and 400 mg groups; n=11 to 500 mg). Risk status (intermediate-2 vs high) was balanced in the 400 mg and 500 mg groups (∼50%), whereas the 300 mg group had more high-risk patients (70%). The majority of patients (88% to 91%) had the JAK2 V617F mutation and most (∼80%) were blood transfusion independent. Mean (median) percentage reductions in spleen volume vs baseline at the end of cycle 3 were 30% (26%) in the 300 mg group, 33% (31%) with 400 mg, and 42% (38%) with 500 mg. A spleen response at the end of cycle 3 was seen in 30% of patients (3/10) in the 300 mg group, 50% (5/10) in the 400 mg group, and 64% (7/11) in the 500 mg group. Patients with constitutional symptoms at baseline in all groups reported a symptom response at the end of cycle 3, with at least a 2-point improvement in or resolution of night sweats in 93% (14/15) of patients, itching in 71% (10/14), early satiety in 56% (10/18), abdominal pain in 56% (10/18), and abdominal discomfort in 50% (10/20). Safety was evaluated in all patients. The most common grade 3–4 hematological adverse event (laboratory) was anemia, with rates across the 300, 400, and 500 mg doses of 33%, 30%, and 55%, respectively. Rates of grade 3–4 thrombocytopenia were 20%, 0, and 9%. There was no grade 3–4 neutropenia. Most common grade 3–4 nonhematological events were diarrhea (10%, 20%, 0), nausea (10%, 10%, 0), and vomiting (10%, 10%, 0). Adverse events in the 300 mg group led to discontinuation in 2 patients: 1 patient had grade 3 anemia, and 1 patient with pre-existing intermittent mild transaminase elevations and polyarthritis had hepatic failure, but completely recovered after discontinuation. No other grade 3–4 increases of AST, ALT, or bilirubin were observed. No deaths were due to an adverse event. Following repeated once-daily oral doses, SAR302503 exposure increased in a dose-dependent manner, with a median time to maximum plasma concentration of 2 to 3 hours. Steady state was achieved by cycle 1 day 15 (C1D15), with a 2.95- to 3.88-fold accumulation of drug. Time-dependent pSTAT3 inhibition was observed at all doses, with the highest mean percentage decreases from baseline (range) occurring at C1D15 (44% to 52%) and C2D1 (40% to 51%). The relationship between PK and PD pSTAT3 suppression can be described by an Emax model. There was also a correlation between percentage of pSTAT3 inhibition and spleen response rate at C1D15 and C2D1 and evidence of a steady state exposure-response relationship for spleen volume reduction at the end of cycle 3. Conclusions: In this Phase II trial, treatment with SAR302503 was associated with clinically meaningful reductions in splenomegaly and improvements in constitutional symptoms. SAR302503 was generally well tolerated in this trial and adverse events were consistent with the known safety profile. Time-dependent decreases in pSTAT3 and exposure-response correlations can be demonstrated across the three doses tested. Sponsored by Sanofi (NCT01420770) Disclosures: Talpaz: Novartis: Research Funding, Speakers Bureau; BMS: Research Funding; ARIAD: Research Funding; Deciphera: Research Funding. Gabrail:Sanofi: Research Funding. Lebedinsky:Sanofi: Employment, Equity Ownership. Gao:Sanofi: Employment, Equity Ownership. Liu:Sanofi: Employment, Equity Ownership. Pardanani:YM BioSciences: Clinical trial support, Clinical trial support Other; BMS: Clinical trial support, Clinical trial support Other; Sanofi: Clinical trial support Other.

Abstract Background:Patients with polycythemia vera (PV) often present with a broad range of clinical characteristics that may contribute to increased risks of cardiovascular (CV) morbidity and mortality, including thrombotic events (TE). Limited contemporary real-world data have been reported about the clinical burden of PV and treatment patterns in the United States. The ongoing REVEAL study collects data on disease burden, clinical management, patient-reported outcomes, and healthcare resource utilization for patients with PV in the United States. This analysis reports clinical characteristics, including underlying CV risk factors, for patients enrolled in the REVEAL study as of April 28, 2016. Methods: REVEAL is a multicenter, nonrandomized, prospective, observational study enrolling patients ≥18 years of age with a PV diagnosis who are actively managed in an academic or community setting. For this analysis, data regarding PV disease and diagnosis, clinical characteristics, and treatment patterns were collected at enrollment during usual-care visits and were based on physician assessment, electronic medical records, and local laboratory values. Ten-year CV risk factors selected for this analysis were adapted from the Framingham Heart Study for CV diseases. Results: At data cutoff, 2307 patients were available for this analysis. Mean (SD) age was 66.3 (12.2) years, 54.4% were male, 89.9% were white, 62.7% had at least some college education, and 51.1% were retired. Approximately 6% of patients had a family history of PV, primarily in parents (35.1%) and siblings (33.8%). A history of second malignancies was reported for 344 patients (14.9%). The majority of patients (84.6%) were diagnosed with PV based on an abnormal blood test alone or in combination with a bone marrow test. Among patients who were diagnosed with a mutational test (n=1078), 95.2% were diagnosed via an abnormal JAK2V617F test result. Abnormal hemoglobin (57.3%), hematocrit (55.4%), or both (47.5%) were among the most common blood values assessed for PV diagnosis. At diagnosis, 58.5% of patients were classified with high-risk PV (age ≥60 years or history of a TE); this percentage increased to 77.3% at REVEAL enrollment. The average (SD) disease duration from diagnosis to enrollment was 5.8 (6.1) years. At enrollment, 91.5% of patients were under active management for PV (phlebotomy ± aspirin, 34.0%; hydroxyurea ± aspirin, 27.0%; and phlebotomy + hydroxyurea ± aspirin, 23.2%). Underlying CV risk factors that were either diagnosed or treated in 86.0% of enrolled patients included hypertension (66.5%), history of smoking (46.2%), current smoking at enrollment (10.9%), obesity (34.2%), hyperlipidemia (27.4%), and diabetes (14.8%). At enrollment, 431 (18.7%) patients reported having ≥1 TE, including 181 patients who had a TE between PV diagnosis and enrollment. Venous and arterial TEs were reported in 11.1% and 8.6% of patients, respectively. Most commonly reported venous TEs were deep vein thrombosis (5.9%) and pulmonary embolism (2.5%); most common arterial TEs were cerebrovascular arterial thrombosis including transient ischemic attack (5.1%) and acute myocardial infarction (1.7%). Increased rates of TEs were observed among patients with hyperlipidemia (23.6%) and hypertension (21.0%; Table 1), compared with patients who did not have any risk factors (10.5%). Conclusion: A large proportion of patients in the REVEAL study had 1 or more underlying CV risks, including age, hypertension, smoking, obesity, hyperlipidemia, and diabetes, which may contribute to the risk of thrombosis. Longitudinal data from REVEAL will provide a better understanding of how these factors affect CV outcomes over time. Disclosures Stein: Incyte Corporation: Membership on an entity's Board of Directors or advisory committees, Research Funding. Naim:Incyte Corporation: Employment, Equity Ownership. Grunwald:Janssen: Research Funding; Forma Therapeutics: Research Funding; Medtronic: Equity Ownership; Alexion: Membership on an entity's Board of Directors or advisory committees; Ariad: Membership on an entity's Board of Directors or advisory committees; Amgen: Research Funding; Incyte Corporation: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding. Oh:Incyte 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; Janssen: Research Funding; CTI: Research Funding. Paranagama:Incyte Corporation: Employment, Equity Ownership. Cordaro:Incyte Corporation: Employment, Equity Ownership. Sun:Incyte Corporation: Employment, Equity Ownership. Parasuraman:Incyte Corporation: Employment, Equity Ownership. Boccia:Celgene: Consultancy, Honoraria, Speakers Bureau; Amgen/Onyx: Consultancy, Honoraria, Speakers Bureau; Gilead: Speakers Bureau; Genentech: Consultancy, Honoraria, Speakers Bureau; Eisai: Consultancy, Honoraria, Speakers Bureau. Mesa:Ariad: Consultancy; CTI: Research Funding; Gilead: Research Funding; Galena: Consultancy; Novartis: Consultancy; Promedior: Research Funding; Celgene: Research Funding; Incyte Corporation: Research Funding.

Abstract Background A recent study from the International Working Group on Myeloproliferative Neoplasms Research and Treatment (IWG-MRT) identified prior arterial events and hypertension as risk factors for subsequent arterial thrombosis and prior venous events and age 65 years or older as risk factors for venous thrombosis in polycythemia vera (PV) (Blood 2014;124:3021). In the current single center study, we sought to validate the aforementioned findings from the IWG-MRT and look into further details regarding arterial versus venous thrombosis in PV. Methods Study patients were selected from our institutional database of myeloproliferative neoplasms (MPN) and fulfilled the 2008 World Health Organization (WHO) criteria for the diagnosis of PV (Blood. 2009;114:937). Screening for the two most frequent mutations other than JAK2 (TET2 and ASXL1) were performed according to conventional methods (Leukemia. 2014;28:2206). Statistical analyses considered clinical and laboratory parameters obtained at time of diagnosis. Results Patient characteristics: Analysis was conducted on 587 patients (median age 60 years; 48% males). ASXL1 and TET2 mutational status was available in 133 patients. Among informative cases, 31% had palpable splenomegaly, 34% microcirculatory symptoms, 30% pruritus, 8% erythromelalgia, 42% hypertension, 9% diabetes and 11% were active tobacco users. TET2 and ASXL1 mutations were documented in 18% and 11%, respectively. During follow-up, 224 (38%) patients died and median follow-up for living patients was 109 months. Median survival was 16 years and leukemic or fibrotic transformations were documented in 4% and 14%, respectively. Thrombotic events: A total of 235 (40%) patients experienced at least one thrombotic event before or after diagnosis and included 153 (26%) arterial and 104 (18%) venous events. Thrombotic events were recorded before or at time of diagnosis in 146 (25%) patients and included 97 (17%) arterial and 55 (9%) venous events. Thrombotic events after diagnosis were recorded in 128 (22%) patients and included 82 (14%) arterial and 57 (10%) venous events. Associations for arterial, venous or all thrombotic events occurring at any time before or after time of diagnosis: The occurrence of any thrombotic event before or after diagnosis correlated with active tobacco use (p=0.04), diabetes history (p=0.03), hyperlipidemia (p=0.04) and major hemorrhage (p=0.03). The occurrence of any arterial event before or after diagnosis correlated with advanced age (p=0.006), diabetes history (p=0.005), hypertension history (p=0.004) and hyperlipidemia (p<0.0001). The occurrence of any venous event before or after diagnosis correlated with female sex (p=0.008), younger age (p<0.0001), lower platelet count (p=0.0014) and palpable splenomegaly (p=0.006). TET2 or ASXL1 mutations did not correlate with overall, arterial or venous thrombosis. Risk factors for arterial versus venous events after time of diagnosis: In univariate/multivariable analysis, thrombosis-free survival (TFS) was adversely affected by prior vascular events (p=0.002/0.03 multivariable) and increased leukocyte count (p=0.03/0.03); arterial thrombosis-free survival was adversely affected by prior arterial events (p<0.0001/P<0.0001), hyperlipidemia (p=0.001/0.03), hypertension (p=0.02/NS) and advanced age (p=0.02/NS); venous thrombosis-free survival was adversely affected by prior venous events (p=0.04/0.05), increased leukocyte count (p=0.0009/0.002), and younger age (p=0.02/NS). In addition, major hemorrhage at diagnosis was associated subsequent venous thrombosis in both univariate and multivariable analysis. TET2 or ASXL1 mutations did not affect the risk of overall, arterial or venous thrombosis. Conclusions In contemporarily managed patients with PV, prior vascular events predict future events for both arterial and venous thrombosis; additional risk factors included hyperlipidemia for arterial and increased leukocyte count for venous thrombosis. The current study also identifies association of arterial thrombosis in general with older age and history of hypertension, diabetes or hyperlipidemia whereas venous thrombosis was associated with younger age, female sex and palpable splenomegaly. Additional findings included association of major hemorrhage with thrombosis and higher platelet count with lower risk of venous thrombosis. Disclosures No relevant conflicts of interest to declare.

Abstract Background In polycythemia vera (PV), abnormal karyotype at diagnosis has been reported in 10% to 20% of patients and some studies have suggested an association with inferior survival (Leukemia2013;27:1874) . In the current study, we examined the prognostic contribution of abnormal karyotype, in general, and specific abnormalities, in particular, in newly diagnosed PV. Methods Study patients were selected from our institutional database of myeloproliferative neoplasms (MPN) and fulfilled the 2008 World Health Organization (WHO) criteria for diagnosis of PV (Blood. 2009;114:937). Cytogenetic analysis and reporting was done according to the International System for Human Cytogenetic Nomenclature (Cytogenetic and Genome Research2013;141:1-6). Assignment as "unfavorable karyotype" was according to criteria established for PMF: favorable = normal + favorable abnormalities; unfavorable = unfavorable abnormalities (Leukemia. 2011;25:82). Screening for the two most frequent mutations in PV, other than JAK2 (i.e. TET2 and ASXL1), were performed according to conventional methods (Leukemia. 2014;28:2206). Statistical analyses considered clinical and laboratory parameters obtained at time of diagnosis. Results Patient characteristics: Median (range) values for the 239 study patients (53% females) included: age 62 (17-94), leukocyte count 11.7 x 10(9)/L (4.3-59.3) and platelet count 479 x 10(9)/L (37-2747). Palpable splenomegaly was present in 26% of the patients, pruritus in 27%, erythromelalgia in in 8%, hypertension in 47%, diabetes in 10% and hyperlipidemia in 28%. Thrombosis history at diagnosis was documented in 33% of the patients and 20% experienced the same after diagnosis. 73% of the patients were "high risk" by conventional risk stratification. Mutation screening for TET2 and ASXL1 was performed in 80 patients and mutational frequencies were 19% and 11% respectively. All study patients provided cytogenetic information, which was abnormal in 46 (19%) patients. The most frequent abnormalities were isolated +9 (n=11; 24% of abnormal karyotype and considered favorable), isolated del(20q) (n=8; 17% of abnormal karyotype and considered favorable), isolated loss of Y chromosome (n=7; 15% of abnormal karyotype and considered favorable) and isolated +8 (n=5; 11% of abnormal karyotype and considered unfavorable). A total of 9 (20% of abnormal karyotype) patients displayed unfavorable karyotype that included +8 in 7 patients, del(11q) in one patient and +20 in one patient. After a median follow-up of 83 months, 70 (29%) deaths, 48 (20%) thrombotic events, 20 (8%) fibrotic progressions and 7 (3%) leukemic transformations were documented. Comparison of patients with and without cytogenetic abnormalities Patients with abnormal cytogenetics were older (p=0.048), displayed lower platelet count (p=0.005) and were more likely to be high risk (p=0.02); there was no significant correlation with TET2 or ASXL1 mutation. In univariate analysis, patients with abnormal cytogenetics displayed inferior leukemia-free (p=0.007; HR 10.6, 95% CI 1.9-58.7), myelofibrosis-free (p<0.0001; HR 7.7, 95% CI 3.1-19.3) and overall (p=0.13; HR 1.6, 95% CI 0.9-2.8) survival. Furthermore, the difference in overall survival became significant when cytogenetic abnormalities were classified into unfavorable (p=0.006) and favorable (p=0.6) categories. On the other hand, inferior leukemia-free and myelofibrosis-free survival was noted in both patients with favorable and unfavorable cytogenetic abnormalities, when compared to normal karyotype. During multivariable analysis that included age and leukocytosis (≥15 x 10 (9)/L) as covariates, the adverse effect of abnormal cytogenetics on leukemia-free (p=0.009) or myelofibrosis-free (p<0.0001) survival and that of unfavorable karyotype on overall (p=0.05) survival were shown to be independent. Finally, patients with abnormal cytogenetics were less likely to experience thrombosis after diagnosis (p=0.04; HR 0.3, 95% CI 0.09-0.97), an effect that was independent of both age and thrombosis history. Conclusions Cytogenetic abnormalities in PV confer an independent adverse prognostic effect on overall, leukemia-free and myelofibrosis-free survival, but not thrombosis-free survival; the adverse effect on leukemia-free and myelofibrosis-free survival was seen with both favorable and unfavorable cytogenetic abnormalities. Disclosures No relevant conflicts of interest to declare.

Abstract Background : Polycythemia vera (PV) is a myeloproliferative neoplasm characterized by erythrocytosis, and in many cases leukocytosis and thrombocytosis. PV is driven by activating mutations in the JAK/STAT pathway, primarily JAK2V617F. For high-risk patients, a commonly used first-line therapy is hydroxyurea (HU); however, a subgroup of patients become intolerant of or resistant to HU. The phase 3 RESPONSE trial compared ruxolitinib (RUX) and best available therapy (BAT) in patients with PV who were intolerant of or resistant to HU (modified European LeukemiaNet criteria). Patients randomized in the BAT arm were permitted to cross over to receive RUX from Week 32 of the study. The results of the primary analysis comparing RUX to BAT prior to crossover have been reported, in which RUX was superior to BAT in achieving hematocrit control, reductions in spleen volume, and improvements in PV-related symptoms. This current analysis was conducted to evaluate the efficacy of RUX treatment in patients who crossed over from BAT relative to their original BAT treatment and relative to those originally randomized to RUX. Methods : Enrollment criteria included PV diagnosis, age ≥18 years, resistance to or intolerance of HU, splenomegaly, and phlebotomy requirement to control hematocrit. Patients were randomized 1:1 to receive open-label RUX 10 mg BID or BAT administered based on investigator judgment. BAT may have included HU, interferon/pegylated interferon, pipobroman, anagrelide, immunomodulators (eg, lenalidomide or thalidomide), or no medication. The protocol allowed for dose modifications (RUX, 5-mg BID increments [25 mg BID max]; BAT was adjusted per investigator judgment). Patients in the BAT group could cross over to RUX from Week 32 if they had not met the primary endpoint, or after Week 32 due to protocol-defined disease progression. The primary study endpoint was a composite of hematocrit control and a ≥35% reduction in spleen size at Week 32. Hematocrit was assessed at screening, every 2 weeks from Day 1 to Week 12, followed by every 4 weeks until Week 32, and 2, 4, 6, 8, 16, 24, and 32 weeks following crossover. Spleen volume was assessed by magnetic resonance imaging at screening and study Weeks 16, 32, 48, 64, 80 and every 32 weeks thereafter. The number of phlebotomy procedures was evaluated over time in each group. Results : A total of 110 patients were randomized to RUX and 112 to BAT; study discontinuation by Week 32 (before crossover was permitted) was 11% in both groups. However, most patients in the BAT arm crossed over to receive RUX treatment immediately after the Week 32 visit (84% between Weeks 32 and 48); only 3% of patients remained in the BAT arm compared with 85% in the RUX arm at the time of the data analysis (median 81-week follow-up). With up to 32 weeks on BAT therapy, 25% of patients in this group did not require a phlebotomy; in contrast, with up to 32 weeks on RUX, 79% of patients after crossover and 74% of patients initially randomized to RUX did not require phlebotomy. The number of phlebotomy procedures adjusted for 100 patient-years during BAT therapy was 196.8 vs 38.5 after crossover to RUX and 34.1 on randomized RUX treatment. Reduction in spleen volume from baseline at any visit occurred in 49% of patients receiving BAT, vs 73% of patients after crossover to RUX and 88% of patients initially randomized to RUX. The proportion of patients achieving at least a 35% reduction in spleen volume (best percentage change) was 1.8% during BAT treatment vs 38.5% after crossover to RUX and 60.0% during randomized RUX treatment. Conclusion : Treatment with RUX after crossover from BAT resulted in improved clinical outcomes compared with original BAT treatment. These findings support the primary RESPONSE results and further validate the efficacy of RUX in this patient population. Disclosures Kiladjian: Novartis Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Off Label Use: Ruxolitinib is a JAK1/JAK2 inhibitor approved for the treatment of patients with intermediate or high-risk myelofibrosis, including primary myelofibrosis, post polycythemia vera myelofibrosis, and post-essential thrombocythemia myelofibrosis. Vannucchi:Novartis Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Masszi:Novartis Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees. Durrant:Novartis Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Harrison:Novartis Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Mesa:Incyte Corporation: Research Funding; CTI: Research Funding; Gilead: Research Funding; Genentech: Research Funding; Eli Lilly: Research Funding; Promedior: Research Funding; NS Pharma: Research Funding; Sanofi: Research Funding; Celgene: Research Funding. Jones:Incyte Corporation: Employment, Equity Ownership. He:Incyte Corporation: Employment, Equity Ownership. Li:Novartis Pharmaceuticals : Employment, Equity Ownership. Habr:Novartis Pharmaceuticals: Employment, Equity Ownership. Verstovsek:Incyte Corporation: Research Funding.

Abstract Background The International Working Group for Myeloproliferative Neoplasms (MPN) Research and Treatment (IWG-MRT) has previously identified older age, leukocytosis, venous thrombosis and abnormal karyotype as risk factors for overall survival (OS) in polycythemia vera (PV), and older age, abnormal karyotype and leukocytes ≥15 × 109/l as risk factors for leukemia-free survival (LFS) (Leukemia2013;27:1874). Serum lactate dehydrogenase (LDH) is a surrogate quantitative measure of cell turnover and tumor burden. We hypothesized that, compared to leukocyte count, serum LDH might be a biologically more accurate indicator of tumor aggression and sought to examine its potential utility as a prognostic biomarker in PV. Methods Study patients were selected from our institutional database of MPN based on their meeting the 2008 or 2016 World Health Organization criteria for diagnosis of PV (Blood. 2009;114:937; Blood 2016 127:2391) and availability of serum LDH level, obtained within six months of diagnosis. Information on karyotype and targeted next-generation sequencing was available in a subset of the patients (Blood 2015 126:354). Statistical analyses considered clinical and laboratory parameters obtained at time of diagnosis. Age and leukocyte count prognostic categories were based on previously published IWG-MRT study (Leukemia2013;27:1874). Results Patient characteristics: A total of 216 patients (50% females) met the above-outlined criteria: median (10th-90th percentile) levels were for age 63 years (38-81), hemoglobin 18 g/dL (16.6-20.7), platelets 467 x 10(9)/L (237-833), leukocyte count 11.7 x 10(9)/L (7.2-20.3) and spleen size 0 cm (0-2). Pruritus was documented in 28%, microcirculatory symptoms in 31%, erythromelalgia in 6%, hypertension in 45%, diabetes in 7%, active tobacco use in 13%, hyperlipidemia in 25%, palpable spleen in 26% and abnormal karyotype in 15% of informative cases. Grading for bone marrow reticulin fibrosis was documented for 144 patients: 50% grade "0", 42% grade "1", 7% grade "2" and 1 grade "3". Thrombosis history at diagnosis was documented in 26% of patients and occurred after diagnosis in 19%. Mutation analysis was available in 72 patients and revealed TET2 mutations in 18 (25%), ASXL1 in 5 (7%), SRSF2 in 2 (3%) and IDH2 in one (1.4%). Serum LDH levels and correlates: Median serum LDH level was 226 U/L (range 71-1008); the upper normal limit (UNL) for Mayo Clinic was 222 U/L. Increased serum LDH was recorded in 110 (51%) patients that included 26 (12%) patients with LDH ≥1.5 x UNL. A significant correlation was demonstrated between increased serum LDH and older age (p=0.007), female sex (p=0.04), leukocytosis (p=0.01), venous thrombosis history (p=0.005) and, interestingly, absence of active tobacco use (p=0.003); no correlation was noted for bone marrow reticulin fibrosis, presence of palpable splenomegaly, abnormal karyotype or ASXL1 mutation. Survival analysis: After a median follow-up of 77 months, 82 (38%) deaths, 8 (3.7%) leukemic transformations, 13 (6%) fibrotic progressions and 41 (19%) thrombotic events were documented. In univariate analysis, the following adversely affected OS: advanced age (P<0.0001), increased LDH as a continuous variable (p=0.0006), LDH ≥1.5 x UNL (p<0.0001), leukocyte count ≥15 x 10(9)/L (p=0.02) and arterial thrombosis history (p=0.001). In multivariable analysis, only age and LDH remained significant; multivariable HR (95% CI) were 5.4 (2.8-10.4) for age ≥67 years, 3.2 (1.8-6.0) for LDH ≥1.5 x UNL and 2.4 (1.2-4.7) for age 57 to 66 years. In the subset of patients with available information on karyotype and non-JAK2 mutations (n=72), advanced age, LDH ≥1.5 x UNL and ASXL1 mutations remained significantly associated with inferior survival. Serum LDH also predicted leukemic transformation (HR 17.8, 95% CI 4.1-78) and fibrotic progression (HR 11.6, 95% CI 25-53.7); in multivariable analysis, only serum LDH ≥1.5 x UNL (HR 22.3, 95% CI 2.1-234.6) and abnormal karyotype (HR 9.5, 95% CI 1.2-74.7) predicted leukemic transformation and only the former predicted fibrotic progression. Conclusions Serum LDH is a simple and inexpensive biomarker that might supersede leukocyte count as an independent predictor of overall, leukemia-free and myelofibrosis-free survival in PV; advanced age and ASXL1 mutations also retained significance for OS and abnormal karyotype for LFS. Disclosures No relevant conflicts of interest to declare.

Abstract Background: NS-018 is an oral, selective, small molecule inhibitor of Janus kinase 2 (JAK2).In the previously-reported Phase 1 portion, patients with myelofibrosis (MF) who received NS-018 achieved steady-state plasma levels above the IC50 for JAK2 at all doses (75mg QD - 400 mg BID). 300 mg QD was chosen as the recommended dose (RD) for Phase 2 portion of the study. OBJECTIVE: The purpose of this study was to determine the safety, tolerability and efficacy of orally-administered NS-018 in patients with PMF, post-PV MF, or post-ET MF. METHODS: This multicenter, Phase 1/2, 3+3 dose-escalation study of NS-018 enrolled patients with IPSS intermediate-1, intermediate-2, or high risk PMF, post-PV MF, or post-ET MF. NS-018 was dosed orally daily (QD) or twice daily (BID) in 28-day cycles. In Phase 1, changes in spleen size were assessed by manual palpation, quality of life with the Myelofibrosis Symptom Assessment Form (MF-SAF), and responses according to the IWG-MRT/ELN consensus criteria. Bone marrow fibrosis was evaluated by biopsy, according to standard practice at the sites. Changes from baseline in grade of BM fibrosis were categorized as improvement, stabilization, or worsening. The Phase 1 portion of the study is complete. In the ongoing Phase 2 portion, spleen size is being assessed by palpation and by centrally-read MRI, and quality of life evaluated by the Myeloproliferative Neoplasm Symptom Assessment Form (MPN-SAF). RESULTS: 48 patients were enrolled across 10 dosing cohorts (75-400 mg QD/100-400 mg BID) in Phase 1. Patient characteristics: 37 PMF, 5 post-PV MF, 6 post-ET MF; median age (range) 69.5 yrs (38-83); M/F:29/19; 35 JAK2V617F+, and 23 previously treated with a different JAK2 inhibitor. The data cutoff for this analysis was June 30, 2016 (median follow-up time of 279.5 [range 5-1806] days from screening), at which time 10 patients remained on treatment. The median number of treatment cycles was 10 (1-65). Reasons for treatment discontinuation were disease progression (PD, n = 13), adverse events (AE, n = 8), physician consideration (n = 6), patient request (n = 4), and protocol non-compliance (n = 1). The 300 mg QD dose was selected as the phase 2 recommended dose (P2RD) in terms of tolerability and efficacy. For the 48 patients, reductions in MF-SAF score were observed for all symptoms after 3 cycles, including patients with priorJAK2 inhibitor treatment. Among 36 splenic-evaluable patients with baseline splenomegaly > 5 cm and treatment for > 1 cycle, 20 (56%) showed > 50% reduction in spleen size (confirmed for > 8 weeks in 16 patients), including 9/19 (47%) patients with prior JAK2 treatment. According to IWG criteria, 14/36 (39%) patients showed splenic clinical improvement for > 8 weeks, 4 with hemoglobin CI, and 1 with platelet CI. Twenty-nine patients with prior JAK inhibitor treatment have been enrolled into the phase 2 portion of the trial. Patient characteristics: 13 PMF, 12 post-PV MF, 4 post-ET MF; median age (range) 67 yrs (48-86). The reason for discontinuation of prior JAK2 inhibitor treatment: AEs (62%) and PD (38%). To date, the median number of treatment cycles is 6 (1-20). The majority of grade 3/4 AEs were hematologic and the most common hematologic toxicities were anemia (21%) and thrombocytopenia (17%). Non-hematologic AEs were mostly grade 1/2, and the other AEs shown in > 10% of patients was nausea (14%). Updated Phase 2 efficacy and safety data will be presented at the meeting. CONCLUSIONS: The RP2D dose of NS-018 was 300 mg QD. This dose provided a durable dosing schedule, an acceptable safety profile, splenic size reductions and clinical symptom improvement. Phase 2 is ongoing and includes patients previously treated with a different JAK2 inhibitor. Disclosures Talpaz: Novartis: Research Funding; Incyte Corporation: Other: Travel expense reimbursement, Research Funding; Ariad: Other: Expense reimbursement, travel accomodation expenses, Research Funding; Pfizer: Consultancy, Other: travel accomodation expenses, Research Funding. Ritchie:Pfizer: Honoraria; Arian: Speakers Bureau; Celgene: Speakers Bureau; Novartis: Honoraria; Incyte: Speakers Bureau. Odenike:Suneisis: Honoraria, Membership on an entity's Board of Directors or advisory committees; CTI/Baxter: Honoraria, Membership on an entity's Board of Directors or advisory committees; Geron: Research Funding; Spectrum: Honoraria, Membership on an entity's Board of Directors or advisory committees; Algeta: Honoraria, Membership on an entity's Board of Directors or advisory committees; Sanofi-Aventis: Honoraria, Membership on an entity's Board of Directors or advisory committees; Incyte: Honoraria, Membership on an entity's Board of Directors or advisory committees. Jamieson:GlaxoSmithKline: Research Funding; CTI Biopharma: Research Funding; Johnson & Johnson: Research Funding. Stein:Incyte: Membership on an entity's Board of Directors or advisory committees. Mesa:CTI: Research Funding; Promedior: Research Funding; Celgene: Research Funding; Gilead: Research Funding; Incyte: Research Funding; Galena: Consultancy; Ariad: Consultancy; Novartis: Consultancy.

Abstract Background: Cytoreductive therapy with hydroxyurea (HU) has been considered first line therapy for patients with high risk polycythemia vera (PV) and essential thrombocythemia (ET) since the results of the PVSG-08 trial demonstrated thrombotic risk reduction (Fruchtman SM et al 1997) for PV and PT1 for ET (Harrison CN et al 2005). Although HU is well tolerated by most patients and has been shown to reduce thrombotic risk in this setting, concern regarding the leukemogenic potential of this oral ribonucleotide reductase inhibitor balanced by the observation of molecular responses with interferon-α (IFN-α) led us to compare the clinical response and tolerability of pegIFN-α (PEG) and HU in a global, randomized, phase III trial. Methods : MPD-RC 112 trial (NCT01258856) enrolled patients with high risk (age >60 years, history of thrombosis, extreme thrombocytosis, symptomatic splenomegaly, uncontrolled cardiovascular risk factors), newly diagnosed (<5 years), WHO defined ET/PV that were treatment naïve (HU <3 months) and randomized (1:1) to PEG or HU. The primary endpoint was complete hematologic response (CHR) rate by European LeukemiaNet (ELN) criteria between the arms after 12 months of therapy. A planned interim analysis based on intent-to-treat with testing boundaries for efficacy and futility was conducted after 75 patients were on study for 12 months. Response assessment by ELN criteria were conducted by blinded review by 4 investigators (JM, RAM, AY, RH). Intent-to-treat analysis was conducted for efficacy endpoints (HU n=39; PEG n=36). Safety analysis included all patients who received treatment (HU n=36; PEG n=36). Results: Patients: The MPD-RC 112 trial involved 24 centers in 6 countries; enrollment began 09/2011 and concluded 7/2016 prior to full accrual due to study drug availability with 168 patients enrolled (Table 1 for 75 patients in the interim analysis). There was no imbalance between arms with respect to history of thrombosis, erythromelalgia, diabetes, hypertension, but age was significantly older on HU. This remained true when analyzing by ET/PV disease strata with the exception of diabetes which was slightly imbalanced within the PV cohort (HU 5/23, 22%; PEG 0/21, 0%; p<0.05). Response: CHR and PHR were observed in 13 (33%) and 14 (36%) patients for an overall response rate (ORR) of 69% (27/39) for HU, and 10 (28%) and 19 (53%) for an ORR of 81% (29/36) for PEG (CHR comparison p=0.60 based on z-test which did not cross either testing boundary). 10 patients randomized to HU were not evaluable for 12-month response due to never initiating treatment (n=3) or early study discontinuation for AEs (n=1), patient withdrawal (n=5), or treatment non-compliance (n=1). 3 patients were not evaluable for response on PEG due to early study discontinuation for AEs (n=1), physician decision (n=1), or patient withdrawal (n=1). Excluding patients who never initiated treatment did not impact the primary endpoint comparison (HU 13/36, 36%; PEG 10/36, 28%; p=0.45). For ET, CHR and PHR were observed in 7 (44%) and 4 (25%) patient on HU, and 6 (40%) and 6 (40%) for PEG (CHR comparison p=0.83). For PV, CHR and PHR were observed in 6 (26%) and 10 (44%) patients on HU, and 4 (19%) and 13 (62%) for PEG (CHR comparison p=0.58). Normalization of spleen by palpation at 12 months was seen in 2/7 (29%) and 5/7 (71%) of the HU and PEG treated patients with palpable spleen at baseline, respectively. Among 38 PV patients, rate of phlebotomy use at 12 months was 0/18 (0%) vs 5/20 (20%) on HU and PEG (p=0.02). From baseline to best score through 12 months, 9/28 (32%) and 12/34 (35%) patients with data on HU and PEG, respectively, had a ≥50% reduction in MPN-SAF Total Symptom Score (p=0.79). Toxicity: No Grade 4 AEs occurred in either treatment arm. Overall, Grade 3 AEs occurred in 5/36 (14%) HU patients and 16/36 (44%) PEG patients (Grade 3 hematologic: 4/36 [11%] HU vs 8/36 [22%] PEG; Grade 3 non-hematologic: 5/36 [14%] HU vs 16/36 [44%] PEG). See Table 2 for Grade 3 AEs regardless of attribution occurring in >10% of patients in either arm. Conclusions: This interim analysis does not show a clear difference in primary endpoint of CHR between HU and PEG. A comparative analysis of the quality of life and symptom burden will provide further insight into the tolerability of these agents (Mesa et al ASH 2016). The final results of this pivotal trial will provide necessary data required to firmly establish the optimal first line therapy for patients with high risk ET/PV. Disclosures Mascarenhas: CTI Biopharma: Research Funding; Janssen: Research Funding; Promedior: Research Funding; Roche: Research Funding; Novartis: Other: DSMB , Research Funding; Incyte: Other: Clinical Trial Steereing Committee, Research Funding. Mesa:Celgene: Research Funding; Promedior: Research Funding; CTI: Research Funding; Gilead: Research Funding; Incyte: Research Funding; Galena: Consultancy; Ariad: Consultancy; Novartis: Consultancy. Yacoub:Alexion: Honoraria; Seattle Genetics: Consultancy, Honoraria, Speakers Bureau; Incyte: Consultancy, Honoraria, Speakers Bureau. Harrison:Baxaltra: Consultancy, Honoraria, Speakers Bureau; Incyte Corporation: Honoraria, Speakers Bureau; Gilead: Honoraria, Speakers Bureau; Shire: Honoraria, Speakers Bureau; Novartis: Consultancy, Honoraria, Other: travel, accommodations, expenses, Research Funding, Speakers Bureau. McMullin:Novartis: Honoraria, Speakers Bureau. Vannucchi:Novartis: Honoraria, Speakers Bureau. Kiladjian:Novartis: Honoraria, Research Funding; AOP Orphan: Membership on an entity's Board of Directors or advisory committees, Research Funding. Mead:Novartis: Honoraria, Research Funding, Speakers Bureau. Kessler:Incyte: Honoraria. Ritchie:Celgene: Consultancy, Other: Travel, Accomodations, Expenses, Speakers Bureau; Incyte: Consultancy, Speakers Bureau; Novartis: Consultancy, Other: Travel, Accommodations, Expenses, Research Funding, Speakers Bureau; Ariad: Speakers Bureau; Pfizer: Consultancy, Research Funding; Astellas Pharma: Research Funding; Bristol-Meyers Squibb: Research Funding; NS Pharma: Research Funding. Schlenk:Amgen: Research Funding; Pfizer: Honoraria, Research Funding.

Abstract Background: Polycythemia vera (PV) is characterized by erythrocytosis, thrombocytosis, and/or leukocytosis and a broad range of disease-related symptoms. In high-risk patients, the most common first-line treatment is hydroxyurea (HU). The open-label RESPONSE trial demonstrated that ruxolitinib (RUX), a JAK1/JAK2 inhibitor, provided superior efficacy compared with best available therapy in patients with PV who were resistant to or intolerant of HU according to modified European LeukemiaNet (ELN) criteria. This study (RELIEF) was conducted in patients receiving a stable dose of HU and who were generally well controlled but reporting disease-associated symptoms, comparing the change in PV-related symptom burden in patients continuing their HU therapy with those switching to RUX treatment. Methods: RELIEF was a randomized, multicenter, double-blind, double-dummy, phase 3b study of patients with PV aged ≥18 years on a stable dose of HU monotherapy and reporting PV-related symptoms. Patients were required to be receiving HU for ≥12 weeks prior to enrollment and on the same dose level for the last 4 weeks, and have a score ≥8 on the Myeloproliferative Neoplasm Symptom Assessment Form (MPN-SAF) cytokine total symptom score (TSS-C). The TSS-C comprised symptoms of itching, tiredness, muscle ache, night sweats, and sweats while awake; each symptom was rated on a scale of 0=absent to 10=worst imaginable, with a maximum TSS-C score of 50. Patients also had to meet one of the following: ≤1 phlebotomy in the previous 6 months or no palpable splenomegaly. Those eligible were randomized 1:1 to receive RUX 10 mg BID and HU-placebo, or HU at the same dose/schedule and RUX-placebo. Dose adjustments were permitted for safety and efficacy. After Week 16, patients could receive open-label RUX until Week 48. The primary endpoint was the proportion of patients with a ≥50% reduction in TSS-C at Week 16; secondary endpoints included proportion of patients with a ≥50% reduction in individual TSS-C symptoms and safety. Results: Overall, 54 and 56 patients were randomized to RUX and HU, respectively; 87.0% and 89.3% remained on treatment through Week 16. At baseline, the median age (range) was 64 (36-87) in the RUX group and 66 (19-85) in the HU group; 44% and 61% were men. The majority of patients in the RUX and HU groups did not have baseline platelet counts or WBC above ELN thresholds: platelets >400 and ≤600 x 109/L (RUX 31.5%, HU 28.6%), >600 x 109/L (3.7%, 8.9%); WBC >10 and ≤15 x 109/L (16.7%, 16.1%), >15 x 109/L (11.1%, 14.3%). In the RUX and HU groups, the mean TSS-C at screening (22.4, 23.1) was higher than that at baseline (16.7, 18.0); the ratio of screening to baseline TSS-C was 1.7 and 1.6. The proportion of patients achieving a ≥50% reduction from baseline in TSS-C at Week 16 (primary endpoint) was 43.4% in the RUX group and 29.6% in the HU group (P=0.139; OR, 1.82; 95% CI, 0.82-4.04). The proportions of patients in the RUX vs HU groups achieving a ≥50% reduction in scores for itching and tiredness at Week 16 were 40.0% vs 26.4% and 54.2% vs 32.0%, respectively. Median percentage changes in individual TSS-C symptoms are shown in Table 1. Additional analyses found no correlation between individual changes in HU dose from baseline to Weeks 13-16 and percentage change in TSS-C in the HU arm (r2=0.030). Even patients maintaining the same HU dose from prior to study entry through Week 16 reported symptom improvement: 12/35 (34.3%) with no dose change, 4/12 (33.3%) with a dose increase, and 0/9 (0%) with a dose decrease had a ≥50% reduction in TSS-C. The most common nonhematologic adverse events in the RUX arm on randomized treatment were fatigue (20.4% RUX vs 10.7% HU), headache (16.7% vs 5.4%), and dizziness (13.0% vs 8.9%). The most common adverse events on HU were diarrhea (9.3% RUX vs 19.6% HU) and constipation (7.4% vs 12.5%); most events were grade 1 or 2. Grade 3 or 4 anemia or thrombocytopenia (lab values) were not reported in the RUX group; two patients in the RUX group had grade 3 or 4 neutropenia. Conclusion: In generally well controlled PV patients receiving a stable dose of HU, there was a positive trend in symptom improvement for patients switched to RUX therapy versus those continuing on HU therapy, although this was not statistically significant. The 34% response rate among patients who continued to receive a stable HU dose suggests a placebo effect that led to an underpowered study. Further analyses are required to better interpret these findings. Disclosures Off Label Use: Ruxolitinib is a JAK1/JAK2 inhibitor approved for the treatment of patients with intermediate or high-risk myelofibrosis, including primary myelofibrosis, post polycythemia vera myelofibrosis, and post-essential thrombocythemia myelofibrosis. Vannucchi:Novartis Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Yacoub:Alexion Pharmaceutical: Membership on an entity's Board of Directors or advisory committees; Seattle Genetics: Membership on an entity's Board of Directors or advisory committees; Sanofi Aventis: Membership on an entity's Board of Directors or advisory committees. Koschmieder:Novartis Pharmaceuticals: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Byrne:Novartis Pharmaceuticals: Honoraria. Verstovsek:Incyte Corporation: Research Funding. Hunter:Incyte Corporation: Employment, Equity Ownership. Jones:Incyte Corporation: Employment, Equity Ownership. He:Incyte Corporation: Employment, Equity Ownership. Morozov:Novartis Pharmaceuticals: Employment, Equity Ownership.