Search

Summary Background The PROUD-PV and CONTINUATION-PV trials aimed to compare the novel monopegylated interferon ropeginterferon alfa-2b with hydroxyurea, the standard therapy for patients with polycythaemia vera, over 3 years of treatment. Methods PROUD-PV and its extension study, CONTINUATION-PV, were phase 3, randomised, controlled, open-label, trials done in 48 clinics in Europe. Patients were eligible if 18 years or older with early stage polycythaemia vera (no history of cytoreductive treatment or less than 3 years of previous hydroxyurea treatment) diagnosed by WHO's 2008 criteria. Patients were randomly assigned 1:1 to ropeginterferon alfa-2b (subcutaneously every 2 weeks, starting at 100 μg) or hydroxyurea (orally starting at 500 mg/day). After 1 year, patients could opt to enter the extension part of the trial, CONTINUATION-PV. The primary endpoint in PROUD-PV was non-inferiority of ropeginterferon alfa-2b versus hydroxyurea regarding complete haematological response with normal spleen size (longitudinal diameter of ≤12 cm for women and ≤13 cm for men) at 12 months; in CONTINUATION-PV, the coprimary endpoints were complete haematological response with normalisation of spleen size and with improved disease burden (ie, splenomegaly, microvascular disturbances, pruritus, and headache). We present the final results of PROUD-PV and an interim analysis at 36 months of the CONTINUATION-PV study (per statistical analysis plan). Analyses for safety and efficacy were per-protocol. The trials were registered on EudraCT, 2012-005259-18 (PROUD-PV) and 2014-001357-17 (CONTINUATION-PV, which is ongoing). Findings Patients were recruited from Sept 17, 2013 to March 13, 2015 with 306 enrolled. 257 patients were randomly assigned, 127 were treated in each group (three patients withdrew consent in the hydroxyurea group), and 171 rolled over to the CONTINUATION-PV trial. Median follow-up was 182·1 weeks (IQR 166·3–201·7) in the ropeginterferon alfa-2b and 164·5 weeks (144·4–169·3) in the standard therapy group. In PROUD-PV, 26 (21%) of 122 patients in the ropeginterferon alfa-2b group and 34 (28%) of 123 patients in the standard therapy group met the composite primary endpoint of complete haematological response with normal spleen size. In CONTINUATION-PV, complete haematological response with improved disease burden was met in 50 (53%) of 95 patients in the ropeginterferon alfa-2b group versus 28 (38%) of 74 patients in the hydroxyurea group, p=0·044 at 36 months. Complete haematological response without the spleen criterion in the ropeginterferon alfa-2b group versus standard therapy group were: 53 (43%) of 123 patients versus 57 (46%) of 125 patients, p=0·63 at 12 months (PROUD-PV), and 67 (71%) of 95 patients versus 38 (51%) of 74 patients, p=0·012 at 36 months (CONTINUATION-PV). The most frequently reported grade 3 and grade 4 treatment-related adverse events were increased γ-glutamyltransferase (seven [6%] of 127 patients) and increased alanine aminotransferase (four [3%] of 127 patients) in the ropeginterferon alfa-2b group, and leucopenia (six [5%] of 127 patients) and thrombocytopenia (five [4%] of 127 patients) in the standard therapy group. Treatment-related serious adverse events occurred in three (2%) of 127 patients in the ropeginterferon alfa-2b group and five (4%) of 127 patients in the hydroxyurea group. One treatment-related death was reported in the standard therapy group (acute leukaemia). Interpretation In patients with early polycythaemia vera, who predominantly presented without splenomegaly, ropeginterferon alfa-2b was effective in inducing haematological responses; non-inferiority to hydroxyurea regarding haematological response and normal spleen size was not shown at 12 months. However, response to ropeginterferon alfa-2b continued to increase over time with improved responses compared with hydroxyurea at 36 months. Considering the high and durable haematological and molecular responses and its good tolerability, ropeginterferon alfa-2b offers a valuable and safe long-term treatment option with features distinct from hydroxyurea. Funding AOP Orphan Pharmaceuticals AG.

Summary Background Polycythaemia vera is a myeloproliferative neoplasm characterised by excessive proliferation of erythroid, myeloid, and megakaryocytic components in the bone marrow due to mutations in the Janus kinase 2 (JAK2) gene. Ruxolitinib, a JAK 1 and JAK 2 inhibitor, showed superiority over best available therapy in a phase 2 study in patients with polycythaemia vera who were resistant to or intolerant of hydroxyurea. We aimed to compare the long-term safety and efficacy of ruxolitinib with best available therapy in patients with polycythaemia vera who were resistant to or intolerant of hydroxyurea. Methods We report the 5-year results for a randomised, open-label, phase 3 study (RESPONSE) that enrolled patients at 109 sites across North America, South America, Europe, and the Asia-Pacific region. Patients (18 years or older) with polycythaemia vera who were resistant to or intolerant of hydroxyurea were randomly assigned 1:1 to receive either ruxolitinib or best available therapy. Patients randomly assigned to the ruxolitinib group received the drug orally at a starting dose of 10 mg twice a day. Single-agent best available therapy comprised hydroxyurea, interferon or pegylated interferon, pipobroman, anagrelide, approved immunomodulators, or observation without pharmacological treatment. The primary endpoint, composite response (patients who achieved both haematocrit control without phlebotomy and 35% or more reduction from baseline in spleen volume) at 32 weeeks was previously reported. Patients receiving best available therapy could cross over to ruxolitinib after week 32. We assessed the durability of primary composite response, complete haematological remission, overall clinicohaematological response, overall survival, patient-reported outcomes, and safety after 5-years of follow-up. This study is registered with ClinicalTrials.gov , NCT01243944 . Findings We enrolled patients between Oct 27, 2010, and Feb 13, 2013, and the study concluded on Feb 9, 2018. Of 342 individuals screened for eligibility, 222 patients were randomly assigned to receive ruxolitinib (n=110, 50%) or best available therapy (n=112, 50%). The median time since polycythaemia vera diagnosis was 8·2 years (IQR 3·9–12·3) in the ruxolitinib group and 9·3 years (4·9–13·8) in the best available therapy group. 98 (88%) of 112 patients initially randomly assigned to best available therapy crossed over to receive ruxolitinib and no patient remained on best available therapy after 80 weeks of study. Among 25 primary responders in the ruxolitinib group, six had progressed at the time of final analysis. At 5 years, the probability of maintaining primary composite response was 74% (95% CI 51–88). The probability of maintaining complete haematological remission was 55% (95% CI 32–73) and the probability of maintaining overall clinicohaematological responses was 67% (54–77). In the intention-to-treat analysis not accounting for crossover, the probability of survival at 5 years was 91·9% (84·4–95·9) with ruxolitinib therapy and 91·0% (82·8–95·4) with best available therapy. Anaemia was the most common adverse event in patients receiving ruxolitinib (rates per 100 patient-years of exposure were 8·9 for ruxolitinib and 8·8 for the crossover population), though most anaemia events were mild to moderate in severity (grade 1 or 2 anaemia rates per 100 patient-years of exposure were 8·0 for ruxolitinib and 8·2 for the crossover population). Non-haematological adverse events were generally lower with long-term ruxolitinib treatment than with best available therapy. Thromboembolic events were lower in the ruxolitinib group than the best available therapy group. There were two on-treatment deaths in the ruxolitinib group. One of these deaths was due to gastric adenocarcinoma, which was assessed by the investigator as related to ruxolitinib treatment. Interpretation We showed that ruxolitinib is a safe and effective long-term treatment option for patients with polycythaemia vera who are resistant to or intolerant of hydroxyurea. Taken together, ruxolitinib treatment offers the first widely approved therapeutic alternative for this post-hydroxyurea patient population. Funding Novartis Pharmaceuticals Corporation.

Myeloproliferative neoplasms (MPNs) are uncommon in children/young adults. Here, we present data on unselected patients diagnosed before 25 years of age included from 38 centers in 15 countries. Sequential patients were included. We identified 444 patients, with median follow-up 9.7 years (0-47.8). Forty-nine (11.1%) had a history of thrombosis at diagnosis, 49 new thrombotic events were recorded (1.16% patient per year [pt/y]), perihepatic vein thromboses were most frequent (47.6% venous events), and logistic regression identified JAK2V617F mutation (P = .016) and hyperviscosity symptoms (visual disturbances, dizziness, vertigo, headache) as risk factors (P = .040). New hemorrhagic events occurred in 44 patients (9.9%, 1.04% pt/y). Disease transformation occurred in 48 patients (10.9%, 1.13% pt/y), usually to myelofibrosis (7.5%) with splenomegaly as a novel risk factor for transformation in essential thrombocythemia (ET) (P= .000) in logistical regression. Eight deaths (1.8%) were recorded, 3 after allogeneic stem cell transplantation. Concerning conventional risk scores: International Prognostic Score for Essential Thrombocythemia-Thrombosis and new International Prognostic Score for Essential Thrombocythemia-Thrombosis differentiated ET patients in terms of thrombotic risk. Both scores identified high-risk patients with the same median thrombosis-free survival of 28.5 years. No contemporary scores were able to predict survival for young ET or polycythemia vera patients. Our data represents the largest real-world study of MPN patients age < 25 years at diagnosis. Rates of thrombotic events and transformation were higher than expected compared with the previous literature. Our study provides new and reliable information as a basis for prospective studies, trials, and development of harmonized international guidelines for the specific management of young patients with MPN. ispartof: BLOOD ADVANCES vol:6 issue:17 pages:5171-5183 ispartof: location:United States status: published

Thromboembolic events and cardiovascular disease are the most prevalent complications in patients with polycythemia vera (PV) compared with other myeloproliferative disorders and are the major cause of morbidity and mortality in this population. Moreover, a vascular complication such as arterial or venous thrombosis often leads to the diagnosis of PV. The highest rates of thrombosis typically occur shortly before or at diagnosis and decrease over time, probably due to the effects of treatment. Important risk factors include age (≥ 60 years old) and a history of thrombosis; elevated hematocrit and leukocytosis are also associated with an increased risk of thrombosis. The goal of therapy is to reduce the risk of thrombosis by controlling hematocrit to

Most common myeloproliferative neoplasms (MPNs) include polycythemia vera (PV) and essential thrombocythemia (ET). Accurate diagnosis of these disorders remains a clinical challenge due to the lack of specific clinical or molecular features in some patients enabling their discrimination. Metabolomics has been shown to be a powerful tool for the discrimination between different hematological diseases through the analysis of patients&rsquo, serum metabolic profiles. In this pilot study, the potential of NMR-based metabolomics to characterize the serum metabolic profile of MPNs patients (PV, ET), as well as its comparison with the metabolic profile of healthy controls (HC) and secondary thrombocytosis (ST) patients, was assessed. The metabolic profile of PV and ET patients, compared with HC, exhibited higher levels of lysine and decreased levels of acetoacetic acid, glutamate, polyunsaturated fatty acids (PUFAs), scyllo-inositol and 3-hydroxyisobutyrate. Furthermore, ET patients, compared with HC and ST patients, were characterized by decreased levels of formate, N-acetyl signals from glycoproteins (NAC) and phenylalanine, while the serum profile of PV patients, compared with HC, showed increased concentrations of lactate, isoleucine, creatine and glucose, as well as lower levels of choline-containing metabolites. The overall analysis revealed significant metabolic alterations mainly associated with energy metabolism, the TCA cycle, along with amino acid and lipid metabolism. These results underscore the potential of metabolomics for identifying metabolic alterations in the serum of MPNs patients that could contribute to improving the clinical management of these diseases.

EXELS, a post-marketing observational study, is the largest prospective study of high-risk essential thrombocythemia (ET) patients, with an observation time of 5 years. EXELS found higher event rates of acute leukemia transformation in patients treated with hydroxycarbamide (HC). In the current analysis, we report age-adjusted rates of malignant transformation from 3460 EXELS patients exposed to HC, anagrelide (ANA), or both. At registration, 481 patients had ANA treatment without HC exposure, 2305 had HC without ANA exposure, and 674 had been exposed to both. Standard incidence ratios (SIRs) were calculated using data from the Cancer Incidence in Five Continents database to account for differences in age-, gender-, and country-specific background rates. SIRs for acute myelogenous leukemia (AML) were high in ET patients. SIRs for AML were high in HC-treated patients, but AML was rare in ANA-treated patients; no cases of AML were found in patients only treated with ANA. No statistically significant difference was seen between SIRs for ANA and HC treatment for AML or skin cancer. SIRs for other cancers were similar in the HC and ANA groups and close to 1, indicating little difference in risk. Although statistically inconclusive, this study strengthens concerns regarding possible leukemogenic risk with HC treatment. (NCT00202644).

Summary The influence of driver mutations on leukaemic transformation was analysed in 1747 patients with polycythaemia vera or essential thrombocythaemia. With a median follow-up of 7·2 years, 349 patients died and 62 progressed to acute leukaemia or myelodysplastic syndrome. Taking death as a competing risk, CALR genotype was associated with a lower risk of transformation [subdistribution hazard ratio (SHR): 0·13, 95% confidence interval (CI): 0·2–0·9, P = 0·039], whereas JAK2 V617F showed borderline significance for higher risk (SHR: 2·05, 95% CI: 0·9–4·6, P = 0·09). Myelofibrotic transformation increased leukaemic risk, except in CALR-mutated patients. Next generation sequencing of 51 genes at the time of transformation showed additional mutations (median number: 3; range: 1–5) in 25 out of 29 (86%) assessable cases. Mutations (median: 1; range: 1–3) were detected in 67% of paired samples from the chronic phase. Leukaemia appeared in a JAK2 V617F negative clone in 17 (58%) cases, eleven of them being previously JAK2 V617F-positive. JAK2 V617F-mutated leukaemia was significantly associated with complex karyotype and acquisition of TP53 mutations, whereas EZH2 and RUNX1 mutations were more frequent in JAK2 V617F-negative leukaemia. Survival was longer in JAK2 V617F-unmutated leukaemia (343 days vs. 95 days, P = 0·003). In conclusion, CALR genotype is associated with a lower risk of leukaemic transformation. Leukaemia arising in a JAK2 V617F-negative clone is TP53 independent and shows better survival.

Myelofibrosis (MF) occurs as part of the natural history of polycythemia vera (PV) and essential thrombocythemia (ET), and remarkably shortens survival. Although JAK2V617F and CALR allele burden are the main transformation risk factors, inflammation plays a critical role by driving clonal expansion toward end-stage disease. NF-kappa B is a key mediator of inflammation-induced carcinogenesis. Here, we explored the involvement of miR-146a, a brake in NF-kappa B signaling, in MPN susceptibility and progression. rs2910164 and rs2431697, that affect miR-146a expression, were analyzed in 967 MPN (320 PV/333 ET/314 MF) patients and 600 controls. We found that rs2431697 TT genotype was associated with MF, particularly with post-PV/ET MF (HR = 1.5; p < 0.05). Among 232 PV/ET patients (follow-up time=8.5 years), 18 (7.8%) progressed to MF, being MF-free-survival shorter for rs2431697 TT than CC + CT patients (p = 0.01). Multivariate analysis identified TT genotype as independent predictor of MF progression. In addition, TT (vs. CC + CT) patients showed increased plasma inflammatory cytokines. Finally, miR-146a(-/-) mice showed significantly higher Stat3 activity with aging, parallel to the development of the MF-like phenotype. In conclusion, we demonstrated that rs2431697 TT genotype is an early predictor of MF progression independent of the JAK2V617F allele burden. Low levels of miR-146a contribute to the MF phenotype by increasing Stat3 signaling.

The current consensus on the diagnosis, prognosis, and treatment of essential thrombocythemia (ET) is based on experts' recommendations. However, several aspects of the diagnosis of, prognosis of, and therapy for ET are still controversial. The Delphi method was employed with an expert panel of members of the Spanish Group of Ph-negative Myeloproliferative Neoplasms in order to identify the degree of agreement on the diagnosis, prognosis, and treatment of ET. Nine leading experts selected a total of 41 clinical hematologists with well-known expertise in ET. An electronic questionnaire was used to collect the questions rated in a four-step scale. The questions were grouped into four blocks: diagnosis, risk stratification, goals of therapy, and treatment strategy. After the first round consisting of 80 questions, a second round including 14 additional questions focused on the recommendations advocated by experts of the European LeukemiaNet in 2011 was analyzed. The median and mean values for the first and second rounds were calculated. A summary of the conclusions considered as the most representative of each block of questions is presented. The Delphi method is a powerful instrument to address the current approaches and controversies surrounding ET.

Evaluation of Anagrelide (Xagrid®) Efficacy and Long-term Safety, a phase IV, prospective, non-interventional study performed in 13 European countries enrolled high-risk essential thrombocythemia patients treated with cytoreductive therapy. The primary objectives were safety and pregnancy outcomes. Of 3721 registered patients, 3649 received cytoreductive therapy. At registration, 3611 were receiving: anagrelide (Xagrid®) (n=804), other cytoreductive therapy (n=2666), or anagrelide + other cytoreductive therapy (n=141). The median age was 56 vs. 70 years for anagrelide vs. other cytoreductive therapy. Event rates (patients with events/100 patient-years) were 1.62 vs. 2.06 for total thrombosis and 0.15 vs. 0.53 for venous thrombosis. Anagrelide was more commonly associated with hemorrhage (0.89 vs. 0.43), especially with anti-aggregatory therapy (1.35 vs. 0.33) and myelofibrosis (1.04 vs. 0.30). Other cytoreductive therapies were more associated with acute leukemia (0.28 vs. 0.07) and other malignancies (1.29 vs. 0.44). Post hoc multivariate analyses identified increased risk for thrombosis with prior thrombohemorrhagic events, age ≥65, cardiovascular risk factors, or hypertension. Risk factors for transformation were prior thrombohemorrhagic events, age ≥65, time since diagnosis, and platelet count increase. Safety analysis reflected published data, and no new safety concerns for anagrelide were found. Live births occurred in 41/54 pregnancies (76%). clinicaltrials.gov Identifier: 00567502.

Bone marrow histology is included in the diagnostic criteria of myeloproliferative neoplasms (MPNs). However, some concerns have emerged about its reproducibility. To evaluate the diagnostic accuracy of histology and to assess its correlation with presence of mutations and clinical outcomes, two pathologists reviewed the bone marrow biopsies corresponding to 211 patients with MPN. Despite the low agreement in the evaluation of individual histopathological characteristics, the concordance among pathologists when establishing the diagnosis was good (Kappa index 0·67). The specificity of histology was 100%, 98·5% and 98% in polycythaemia vera (PV), essential thrombocythaemia (ET) and primary myelofibrosis (PMF), respectively, whereas the sensitivity of histological diagnosis was low in PV and ET (32·5% and 54% respectively) and acceptable in PMF (75%). Thirteen out of 146 (9%) patients with clinical ET were diagnosed as prefibrotic PMF. No histological agreement or MPN otherwise unspecified was more frequently observed in JAK2 V617F-positive ET than in CALR-mutated cases, whereas megakaryocytic abnormalities and prefibrotic PMF were more frequently observed in CALR-mutated ET. In conclusion, histological criteria of MPN have a limited diagnostic accuracy due to low sensitivity. Patients with JAK2 V617F-positive MPN have a heterogeneous histology while CALR-positive ET is associated with megakaryocyte abnormalities and prefibrotic PMF.

The JAK2V617F allele burden has been identified as a risk factor for vascular events and myelofibrotic transformation in polycythemia vera (PV) and essential thrombocythemia (ET). However, all previous studies have evaluated a single time point JAK2V617F measurement. Therefore, the frequency and the clinical significance of changes in the JAK2V617F mutant load occurring during the disease evolution remain unknown. In the present study, JAK2V617F monitoring was performed during the follow-up of 347 patients (PV = 163, ET = 184). According to their JAK2V617F evolutionary patterns, patients were stratified as stable

Available information is limited regarding the use of cytoreductive combination therapy in high-risk patients with essential thrombocythemia. This analysis aims to evaluate the clinical relevance and patterns of cytoreductive combination treatment in European high-risk patients with essential thrombocythemia in the Evaluation of Xagrid(®) Efficacy and Long-term Safety study. Of 3643 patients, 347 (9.5%) received combination therapy. Data were recorded at each 6-month update. Of 347 patients who received combination therapy, 304 (87.6%) received hydroxycarbamide + anagrelide. Monotherapies received before this combination were hydroxycarbamide (n=167, 54.9%) and anagrelide (n=123, 40.5%). Median weekly doses of hydroxycarbamide and anagrelide were: 7000 and 10.5 mg when used as prior monotherapy; 3500 and 7.0 mg when used as add-on treatment. Overall, median platelet counts were 581 × 10(9)/L and 411 × 10(9)/L before and after starting hydroxycarbamide + anagrelide, respectively. In patients with paired data (n=153), the number of patients with platelet counts less than 400 × 10(9)/L increased from 33 (21.6%) to 74 (48.4%; P

Standardized response criteria to interpret and compare clinical trials are needed for approval of new therapeutic agents by regulatory agencies. The European LeukemiaNet (ELN) response criteria for essential thrombocythemia (ET) and polycythemia vera (PV) issued in 2009 have been widely adopted as end points in a number of recent clinical trials. However, evidence exists that they do not predict response or provide clinically relevant measures of benefit for the patients. This article presents revised recommendations for assessing response in ET and PV provided by a working group established by ELN and International Working Group-Myeloproliferative Neoplasms Research and Treatment. New definitions of complete and partial remission incorporate clinical, hematological, and histological response assessments that include a standardized symptom assessment form and consider absence of disease progression and vascular events. We anticipate that these criteria will be adopted widely to facilitate the development of new and more effective therapies for ET and PV.

Hematocrit control below 45% is associated with a lower rate of thrombosis in polycythemia vera. In patients receiving hydroxyurea, this target can be achieved with hydroxyurea alone or with the combination of hydroxyurea plus phlebotomies. However, the clinical implications of phlebotomy requirement under hydroxyurea therapy are unknown. The aim of this study was to evaluate the need for additional phlebotomies during the first five years of hydroxyurea therapy in 533 patients with polycythemia vera. Patients requiring 3 or more phlebotomies per year (n=85, 16%) showed a worse hematocrit control than those requiring 2 or less phlebotomies per year (n=448, 84%). There were no significant differences between the two study groups regarding leukocyte and platelet counts. Patients requiring 3 or more phlebotomies per year received significantly higher doses of hydroxyurea than the remaining patients. A significant higher rate of thrombosis was found in patients treated with hydroxyurea plus 3 or more phlebotomies per year compared to hydroxyurea with 0-2 phlebotomies per year (20.5% vs. 5.3% at 3 years; P

Myelofibrosis is a myeloproliferative neoplasm associated with progressive cytopenias and high symptom burden. MF patients with thrombocytopenia have poor prognosis but the presence of thrombocytopenia frequently precludes the use of JAK2 inhibitors. In this study, we assessed quality of life and symptom burden in 418 MF patients with (n = 89) and without (n = 329) thrombocytopenia using prospective data from the MPN-QOL study group database, including the Myeloproliferative Neoplasm Symptom Assessment Form (MPN-SAF) and Total Symptom Score (MPN10). Thrombocytopenia, defined as platelet count 9/L (moderate 51–100 × 109/L; severe ≤50 × 109/L), was associated with anemia (76% vs. 45%, p < 0.001), leukopenia (29% vs. 11%, p < 0.001), and need for red blood cell transfusion (35% vs. 19%, p = 0.002). Thrombocytopenic patients had more fatigue, early satiety, inactivity, dizziness, sad mood, cough, night sweats, itching, fever, and weight loss; total symptom scores were also higher (33 vs. 24, p < 0.001). Patients with severe thrombocytopenia were more likely to have anemia (86% vs. 67%, p = 0.04), leukopenia (40% vs. 20%, p = 0.04), and transfusion requirements (51% vs. 20%, p = 0.002) but few differences in symptoms when compared to patients with moderate thrombocytopenia. These results suggest that MF patients with thrombocytopenia experience greater symptomatic burden than MF patients without thrombocytopenia and may benefit from additional therapies.

The myeloproliferative neoplasms, including polycythemia vera, essential thrombocythemia and myelofibrosis, are distinguished by their debilitating symptom profiles, life-threatening complications and profound impact on quality of life. The role gender plays in the symptomatology of myeloproliferative neoplasms remains under-investigated. In this study we evaluated how gender relates to patients' characteristics, disease complications and overall symptom expression. A total of 2,006 patients (polycythemia vera=711, essential thrombocythemia=830, myelofibrosis=460, unknown=5) were prospectively evaluated, with patients completing the Myeloproliferative Neoplasm-Symptom Assessment Form and Brief Fatigue Inventory Patient Reported Outcome tools. Information on the individual patients' characteristics, disease complications and laboratory data was collected. Consistent with known literature, most female patients were more likely to have essential thrombocythemia (48.6% versus 33.0%; P

Polycythemia vera and essential thrombocythemia (ET) are chronic myeloproliferative neoplasms associated with thrombotic or hemorrhagic complications, and increased risk of transformation to myelofibrosis and acute myeloid leukemia. The main goal of therapy is aimed at preventing vascular events that are the leading cause of morbidity and mortality in these patients. Accordingly, risk stratification is the basis for deciding when to treat a patient with cytoreductive therapy. The European LeukemiaNet has developed a series of management recommendations for front-line and second-line therapy to provide the optimal treatment for the individual patient. There is still controversy about the efficacy and safety of several modalities of cytoreductive treatment in the long-term for both diseases and in the use of antiplatelet therapy in ET. The presence of JAK2V617F and CALR mutations in patients with ET has been related to different thrombotic risks, and this will probably lead to different therapeutic approaches in the near future. On the other hand, the near normal life expectancy of these patients makes a careful analysis of the benefits and risks associated with treatment essential. This review provides our current management strategy of patients with polycythemia vera and ET. CB and AA-L received honoraria for educational lectures from Novartis and Shire. This work was supported by Grants 2014 SGR 567, PI13/00557, PI13/00393, and RD012/0036/0004.

Subclones homozygous for JAK2V617F are more common in polycythemia vera (PV) than essential thrombocythemia (ET), but their prevalence and significance remain unclear. The JAK2 mutation status of 6495 BFU-E, grown in low erythropoietin conditions, was determined in 77 patients with PV or ET. Homozygous-mutant colonies were common in patients with JAK2V617F-positive PV and were surprisingly prevalent in JAK2V617F-positive ET and JAK2 exon 12-mutated PV. Using microsatellite PCR to map loss-of-heterozygosity breakpoints within individual colonies, we demonstrate that recurrent acquisition of JAK2V617F homozygosity occurs frequently in both PV and ET. PV was distinguished from ET by expansion of a dominant homozygous subclone, the selective advantage of which is likely to reflect additional genetic or epigenetic lesions. Our results suggest a model in which development of a dominant JAK2V617F-homzygous subclone drives erythrocytosis in many PV patients, with alternative mechanisms operating in those with small or undetectable homozygous-mutant clones.

Summary The modulation of JAK2 V617F allele burden dynamics was prospectively analysed in 47 patients (26 polycythaemia vera [PV] and 21 essential thrombocythaemia [ET]) treated with first-line hydroxyurea (HU) and compared with the JAK2 V617F dynamics of a control group of 45 PV and ET patients. A partial molecular response (PMR), according to European Leukaemia Net criteria, was observed in 27/47 (57%) patients. Median time to PMR was 14 months (3–66) with a probability of PMR at 3 years of 57%. A significant decrease in JAK2 V617F allele load was observed at 36 months both in PV and ET patients, being the reduction in PV higher than in ET patients (P = 0·01). A haematocrit ≥0·45 L/L was associated with a higher probability of attaining a PMR (HR:3·4; 95%CI:1·02–11·6, P = 0·04). Control group showed a slight increase of JAK2 V617F allele burden over time. The reduction in the mutated allele load comparing treated patients versus controls was highly significant both in PV and ET, demonstrating a clear effect of HU on the JAK2 V617F allele burden. In conclusion, first-line HU can attain PMR in more than 50% of newly diagnosed PV and ET patients, with a continuous decrease of the JAK2 V617F allele burden in PV patients during treatment.

Myeloproliferative neoplasms (MPN) are most common in old people (>60 years) and are rarely identified in children and young adults where information about complication rates and long-term data are lacking. To improve our knowledge, we retrospectively collected cases of young patients diagnosed with MPN before 25 years of age and analysed data of their disease to date, including vascular events and disease evolution. Data were collected in 29 hospital centres from 12 countries. Between 1971 and 2018, 335 young patients were diagnosed for an MPN before the age of 25. They were mostly females (n=246; 73.4%) with a median age of 20.3 years at diagnosis (2.5 months-25 years). Essential thrombocythemia was diagnosed in 234 patients (69.8%), polycythemia vera in 60 (17.9%) and myelofibrosis or unclassified MPN in 41 (12.3%). Most of the diagnoses were made following a coincidental blood count analysis (n=75; 51%) some based on symptoms (n=57; 38.8%) or thrombotic events (n=15; 10.2%). In terms of complications before or at diagnosis, 31 (9.3%) patients experienced thrombosis, mostly venous (75%) and 13 (3.9%) had hemorrhage. At diagnosis, the median leukocyte count was 9x109/l (range: 3-22.8), median hemoglobin count 140 g/l (65-220) and median platelet count 900x109/l (99-3290). To assess the diagnosis, 158 patients (47.2%) had had bone marrow aspirates and 214 (63.9%) a bone marrow biopsy. Mutational status was available in 319 (90%) cases: 194 (60.8%) were JAK2V617F positive, 48 (15%) had a calreticulin mutation, 76 (23.8%) were triple-negative and 1 patient had MPL mutation. The median follow-up of the cohort was 7.7 years (0-46.8) with 134 patients (40%) having follow-up for more than 10 years. 81 female patients (32.9%) experienced pregnancies. During this period, 295 patients (88%) received at least one drug for their MPN: 254 patients (77.2%) received antithrombotic drug and 222 patients (66.5%) a cytoreductive drug. As first line of treatment, hydroxycarbamide was given to 111 patients (50%) whereas anagrelide was given to 56 patients (25.2%) and interferon to 50 (22.5%). During the follow-up, 97 patients (29%) experienced at least one complication. In terms of cardiovascular events, 38 (11.3%) patients experienced thromboses with 50 events in total (recurrences in 12 cases), including 33 venous events (66%) of which 15 were localized in the splanchnic territory (45.5%). Hemorrhagic events were recorded in 34 cases (10.1%). During the follow-up, 39 patients (11.6%) have evolved: 11 from ET to PV (28.2%), 26 into MF (66.7%) and 2 into AML (5.1%). All evolutions were exclusive: one event per patient. At the time of the analysis, 66 patients (19.7%) were declared as lost of follow up and 4 were dead (1.2%). This is the largest cohort of patients aged below 25 years at the time of diagnosis demonstrates that despite their youth most of them (88%) received drug(s) for the management of their MPN. There was a high incidence of complications (29%), with vascular events and disease evolution occurring at equal frequency although death was uncommon (1.2%). Rates of events were disease evolution: 1.51/100pts/y; thromboses: 1.47 and hemorrhages: 1.32. No specific national or international guidance exists for MPN patients of this age; but our data suggest that these are not benign conditions and patients need to be carefully followed and treated. Table. Table. Disclosures Kiladjian: Celgene: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding; AOP Orphan: Membership on an entity's Board of Directors or advisory committees, Research Funding. Giraudier:Novartis: Research Funding. Griesshammer:Novartis: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Harrison:Novartis: Consultancy, Honoraria, Research Funding, Speakers Bureau; Celgene: Consultancy, Honoraria, Speakers Bureau; Roche: Consultancy, Honoraria; Gilead: Honoraria, Speakers Bureau; CTI BioPharma: Consultancy, Honoraria.

Background and objective. An important proportion of patients with polycythemia vera (PV) and essential thrombocythemia (ET) are diagnosed in the seventh and eighth decades of life. Because of the chronic course of PV and ET and the advanced age of patients, many will actually die from age-related ailments instead of the myeloproliferative neoplasm, so the disease's impact on life-expectancy remains largely unknown. This registry‐based study was aimed at investigating the excess mortality attributable to PV and ET in a large series of patients diagnosed and managed according to modern criteria. Methods. We queried the databases of the Spanish Group for Chronic Myeloproliferative Neoplasms (GEMFIN) to retrieve patients diagnosed with PV or ET after 1980. Criteria for diagnosis and treatment modalities were the internationally recommended ones in each period. Excess mortality was defined as the complementary of the ratio between the actuarial survival observed in the cohort of patients and the expected survival derived from the general Spanish population matched to the patients by age, sex, and calendar year at diagnosis, and was estimated by the Dickman's method (Stat Med 2004;23:51). Spanish life-tables stratified by age, sex, and calendar year were obtained from the Human Mortality Database (www.mortality.org). Results. A total of 3,268 patients were included in the study (PV: 1,731; ET: 1,537). Median age (interquartile range) and sex distribution in the PV and ET groups were 67 (55-75) years, 48% females, and 62 (48-74) years, 61% females, respectively. At the study closing date, 270 (16%) patients with PV and 202 (13%) with ET had died. Estimated median survival was 20.2 years for PV patients and 23.8 years for ET patients. Transformation into acute myeloid leukemia/myelodysplastic syndrome was diagnosed in 76 (4.4%) patients with PV and 63 (4.1%) with ET. Three hundred and seventy-one patients (170 ET, 201 PV) had one or more episodes of thrombosis over the course of the disease. No significant excess mortality attributable to ET was detected at 20 years from diagnosis (figure 1a). In PV, mortality did not significantly deviate from matched general population until 18 years from diagnosis (figure 1b). In both diseases, excess mortality significantly increased after the first recorded thrombotic event (figure 1c). Conclusion. From the population viewpoint, ET and PV do not carry an increased excess mortality until late in the second follow-up decade or later. Nevertheless, appearance of a thrombotic event significantly increases the subsequent excess mortality. Figure 1 Figure 1. Disclosures Hernandez Boluda: Incyte: Consultancy; Novartis: Consultancy. Ferrer Marin:Novartis: Consultancy, Research Funding; Incyte: Consultancy. Gómez-Casares:Bristol-Myers Squibb: Speakers Bureau; Incyte: Speakers Bureau; Novartis: Speakers Bureau. Cervantes:Celgene: Membership on an entity's Board of Directors or advisory committees; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Hospital Clinic Barcelona: Employment.

JAK2 exon 12 mutations are associated with more marked and isolated erythrocytosis than JAK2V617F. We analyzed expression profiles of JAK2 exon 12-mutant and wild-type erythroid colonies from patients with polycythemia vera (PV). Exon 12 mutations were associated with interferon-target gene upregulation, STAT1 activation and additional gene expression changes that were quantitatively and qualitatively similar to those in JAK2V617F-heterozygous cells from essential thrombocythemia (ET) patients. These results demonstrate that JAK2 exon 12-mutated PV does not reflect attenuated STAT1 signaling, and that transcriptional consequences of JAK2 mutations are remarkably similar in JAK2 exon 12-mutated PV and JAK2V617F-positive ET.

RESPONSE is an open-label phase 3 study evaluating the Janus kinase 1/Janus kinase 2 inhibitor ruxolitinib versus best available therapy for efficacy/safety in hydroxyurea-resistant or intolerant patients with polycythemia vera. This preplanned analysis occurred when all patients completed the Week 80 visit or discontinued. Objectives included evaluating the durability of the primary response (Week 32 phlebotomy-independent hematocrit control plus ≥35% spleen volume reduction), its components, and that of complete hematologic remission; and long-term safety. Median exposure was 111 weeks; 91/110 (82.7%) patients randomized to ruxolitinib remained on treatment. No patients continued best available therapy (98/112 [87.5%] crossed over to ruxolitinib, most at/soon after Week 32). At Week 32, primary response was achieved by 22.7% vs. 0.9% of patients randomized to ruxolitinib and best available therapy, respectively (hematocrit control, 60.0% vs. 18.8%; spleen response, 40.0% vs. 0.9%). The probability of maintaining primary and hematocrit responses for ≥80 weeks was 92% and 89%, respectively; 43/44 spleen responses were maintained until Week 80. Complete hematologic remission at Week 32 was achieved in 23.6% of ruxolitinib-randomized patients; the probability of maintaining complete hematologic remission for ≥80 weeks was 69%. Among ruxolitinib crossover patients, 79.2% were not phlebotomized, and 18.8% achieved a ≥35% reduction from baseline in spleen volume after 32 weeks of treatment. New or worsening hematologic laboratory abnormalities in ruxolitinib-treated patients were primarily grade 1/2 decreases in hemoglobin, lymphocytes, and platelets. The thromboembolic event rate per 100 patient-years was 1.8 with randomized ruxolitinib treatment vs. 8.2 with best available therapy. These data support ruxolitinib as an effective long-term treatment option for hydroxyurea-resistant or intolerant patients with polycythemia vera. This trial was registered at clinicaltrials.gov identifier: 01243944. V received funding from and participated in advisory boards for Incyte Corporation. AMV served as a consultant for Novartis, participated in speakers bureaus for Novartis and Shire, and received research funding from Novartis. MG received travel reimbursements from Amgen, Roche, Novartis, and Shire. TM served as a consultant for Novartis and Janssen-Cilag. SD received honoraria and research funding from Novartis. CNH received honoraria from Sanofi, Novartis, and Baxter; served on speakers bureaus for Sanofi, Novartis, Shire, and Baxter; received research funding from Novartis; and received travel reimbursement from Novartis. KK received honoraria from Novartis. CB received honoraria from Novartis and Shire. FPan received honoraria from Novartis, Bristol-Myers Squibb, and Roche; served as a consultant for Bristol Myers Squibb and Ariad; received research funding from Novartis; and received travel reimbursements from Novartis and Roche. BM served on speakers bureaus for Novartis and Bristol-Myers Squibb. CBM received honoraria and served on a speakers bureau and as a consultant for Incyte Corporation. RM received honoraria and served as a consultant for Novartis and received research funding from Incyte Corporation, Gilead, CTI BioPharma, and Celgene. MMJ and HZ are employees and stockholders of Incyte Corporation. JL, NF, and DH are employees and stockholders of Novartis. J-JK served as a consultant for Novartis, Shire, and Incyte Corporation and received research funding from Novartis and AOP Orphan Pharmaceuticals.

Purpose Polycythemia vera (PV) is a myeloproliferative neoplasm (MPN) associated with disabling symptoms and a heightened risk of life-threatening complications. Recent studies have demonstrated the effectiveness of JAK inhibitor therapy in patients with PV patients who have a history of prior hydroxyurea (HU) use (including resistance or intolerance), phlebotomy requirements, and palpable splenomegaly. We aimed to determine how these features contribute alone and in aggregate to the PV symptom burden. Patients and Methods Through prospective evaluation of 1,334 patients with PV who had characterized symptom burden, we assessed patient demographics, laboratory data, and the presence of splenomegaly by disease feature (ie, known HU use, known phlebotomy requirements, splenomegaly). Results The presence of each feature in itself is associated with a moderately high symptom burden (MPN symptom assessment form [SAF] total symptom score [TSS] range, 27.7 to 29.2) that persists independent of PV risk category. In addition, symptoms incrementally increase in severity with the addition of other features. Patients with PV who had all three features (PV-HUPS) faced the highest total score (MPN-SAF TSS, 32.5) but had similar individual symptom scores to patients with known HU use (PV-HU), known phlebotomy (PV-P), and splenomegaly (PV-S). Conclusion The results of this study suggest that patients with PV who have any one of the features in question (known HU use, known phlebotomy, or splenomegaly) have significant PV-associated symptoms. Furthermore, it demonstrates that many PV symptoms remain severe independent of the number of features present.

Masked polycythaemia vera (PV) has been proposed as a new entity with poorer outcome than overt PV. In this study, the initial clinical and laboratory characteristics, response to treatment and outcome of masked and overt PV were compared using red cell mass and haemoglobin or haematocrit levels for the distinction between both entities. Sixty-eight of 151 PV patients (45%) were classified as masked PV according to World Health Organisation diagnostic criteria, whereas 16 (11%) were classified as masked PV using the British Committee for Standards in Haematology (BCSH). In comparison with overt PV, a higher platelet count and a lower JAK2V617F allele burden at diagnosis were observed in masked PV. Patients with masked PV needed lower phlebotomies and responded faster to hydroxcarbamide than those with overt PV. Complete haematological response was more frequently achieved in masked than in overt PV (79% vs. 58%, P = 0.001). There were no significant differences in the duration of haematological response, the rate of resistance or intolerance to hydroxycarbamide and the probability of molecular response according to type of PV (masked vs. overt). Overall survival, rate of thrombosis and major bleeding, and probability of transformation was superimposable among patients with masked and overt PV. This work was supported by grants from the Spanish Health Ministry ‘Fondo de Investigación Sanitaria’, PI10/01807,PI13/00557, PI13/00393, AECC Cataluña 2011, Instituto de Salud Carlos III FEDER RD12/0036/0010, SGR2014 567,the ‘Xarxa de Bancs de Tumors sponsored by Pla Director d’Oncologia de Catalunya (XBTC)’. Anna Angona is currently supported by a research grant from RETICS RD12/0036/0010.

Udgivelsesdato: 2007-Feb BACKGROUND: Three main problems hamper the identification of wheat food allergens: (1) lack of a standardized procedure for extracting all of the wheat protein fractions; (2) absence of double-blind, placebo-controlled food challenge studies that compare the allergenic profile of Osborne's three protein fractions in subjects with real wheat allergy, and (3) lack of data on the differences in IgE-binding capacity between raw and cooked wheat. METHODS: Sera of 16 wheat-challenge-positive patients and 6 patients with wheat anaphylaxis, recruited from Italy, Denmark and Switzerland, were used for sodium dodecyl sulfate-polyacrylamide gel electrophoresis/immunoblotting of the three Osborne's protein fractions (albumin/globulin, gliadins and glutenins) of raw and cooked wheat. Thermal sensitivity of wheat lipid transfer protein (LTP) was investigated by spectroscopic approaches. IgE cross-reactivity between wheat and grass pollen was studied by blot inhibition. RESULTS: The most important wheat allergens were the alpha-amylase/trypsin inhibitor subunits, which were present in all three protein fractions of raw and cooked wheat. Other important allergens were a 9-kDa LTP in the albumin/globulin fraction and several low-molecular-weight (LMW) glutenin subunits in the gluten fraction. All these allergens showed heat resistance and lack of cross-reactivity to grass pollen allergens. LTP was a major allergen only in Italian patients. CONCLUSIONS: The alpha-amylase inhibitor was confirmed to be the most important wheat allergen in food allergy and to play a role in wheat-dependent exercise-induced anaphylaxis, too. Other important allergens were LTP and the LMW glutenin subunits.

MYD88 (L265P) mutation is an independent prognostic factor for outcome in patients with diffuse large B-cell lymphoma

Dear Editor,ArecentmutationlocatedintheJAK2 gene, JAK2 V617F, hasbeen shown to play a transcendental role in the constitutiveactivation of its tyrosine kinase activity in an importantnumber of cases of Philadelphia negative myeloproliferativedisorders (Ph-MPDs). This mutation is a useful tool fordiagnosing this diseases because different studies show thatthis mutation is highly frequent in patients with polycythemiavera (PV) and is present in around 50% of the patients withessential thrombocythemia (ET) and idiopathic myelofibrosis(IMF) [1]. Among the clinical features and phenotypes thatcharacterize Ph-MPD patients, thrombotic and hemorrhagicepisodes have been shown to be frequent in these patients.Range values for thrombosis at diagnosis fluctuate between34% to 39% for PV and 10% to 29% for ET [ 2]. Forhemorrhage, the values are much more variable [ 3].The mechanisms accounting for the increased risk ofthrombosis and hemorrhage in Ph-MPD patients are notwell understood. It has been accepted that the occurrence ofprevious venous thrombotic events and age increase the riskof thrombosis [4, 5]. The contribution of cardiovasculardisease risk factors in the development of thrombosis inPh-MPD patients is still unclear. Risk factors for hemor-rhage are more elusive and few have been described [2, 4].Studies are limited concerning the impact of hereditarythrombophilia in the development of thrombotic episodes inPh-MPD patients [6, 7]. In addition, the effect of the JAK2F617 allele in the development of thrombotic events is stillcontroversial [2, 8, 9].Thus, we aimed to ascertain the role of JAK2 V617F andother genetic risk factors in the development of thrombosisin patients diagnosed with Ph-MPD. For this purpose, weevaluated the prevalence of JAK2 V617F mutation andnine additional genetic alterations [FV Leiden, PTG20210A, and ZPI R67Stop are polymorphisms associatedwith venous thrombosis; HPA-1 located in the αIIbβ3integrin, HPA-2 located in von Willebrand factor receptorGIb/IX/V, GPIa C807T, and PSGL-1 are polymorphismsassociated with arterial thrombosis; FVII -323 Del/Ins andTUBB1 Q43P located in the megakaryocyte-specifictubulin β1 are two polymorphisms that increase the riskof hemorrhage] in 212 patients [74 PV, 128 ET, and tenIMF] (94 males, 118 females, median age 60.5±16.1, range21–85 years) followed during a 4-year period in HospitalMorales Meseguer (Murcia) and Hospital del Mar (Barce-lona). Thrombotic complications included venous (N=13)and major arterial thromboses (N=42) as well as microvas-cular alterations such as erythromelalgia (N=17). Severalpatients had two episodes of vascular events: five patientshad both venous and major arterial thromboses and twopatients with erythromelalgia developed an episode ofarterial thrombosis. Fifteen patients had hemorrhage. Weconsidered asymptomatic patients those with no thromboticor hemorrhagic episodes. The analysis of the role of genetic

The JAK2V617F allele burden has been identified as a risk factor for vascular events and myelofibrotic transformation in polycythemia vera (PV) and essential thrombocythemia (ET). However, all previous studies have evaluated a single time point JAK2V617F measurement. Therefore, the frequency and the clinical significance of changes in the JAK2V617F mutant load occurring during the disease evolution remain unknown. In the present study, JAK2V617F monitoring was performed during the follow-up of 347 patients (PV = 163, ET = 184). According to their JAK2V617F evolutionary patterns, patients were stratified as stable 50% (n = 261), stable ≥50% (n = 52), progressive increase (n = 24) and unexplained decrease (n = 10). After a 2,453 person-years follow-up, a total of 59 thrombotic events, 16 major hemorrhages, and 27 cases of myelofibrotic transformations were registered. At multivariate analyses, patients with a persistently high (≥50%) or unsteady JAK2V617F load during follow-up had an increased risk of myelofibrotic transformation (Incidence rate ratio [IRR]: 20.7, 95% CI: 6.5-65.4; P 0.001) and a trend for a higher incidence of thrombosis (IRR: 1.7, 1-3.3; P = 0.05) than patients with a stable allele burden below 50%. In conclusion, JAK2V617F monitoring could be useful in patients with PV and ET for predicting disease's complications, especially myelofibrotic transformation.

Aims The diagnosis of primary myelofibrosis (PMF) strongly relies on the bone marrow biopsy findings, but a report model has not been standardised. Our aim was to establish general recommendations for bone marrow evaluation and standardised reporting in a case suspicious of PMF. Methods The Delphi method was employed to obtain expert consensus. An advisory panel of 10 leading members identifies a total of 37 haematopathology experts to participate. The first Delphi round included a questionnaire with three main groups of items: minimal clinical and laboratory data considered necessary before reporting, minimal descriptive aspects to record and main histological differential diagnosis. The final report content was based on consensus obtained after the second Delphi round. Results The minimal data considered necessary were age, splenomegaly, haemoglobin, leucocyte and platelet counts, differential blood cell count, leucoerythroblastic blood picture, lactate dehydrogenase (LDH) level, BCR-ABL and JAK2 mutational status, reticulin stain and the internal control for the reticulin staining. The minimal descriptive aspects to report were cellularity, osteosclerosis, megakaryocytic morphology and localisation, dense megakaryocytic clusters, quantity of granulocytic precursors, grade of myelofibrosis in a scale of 4, and a proposed final diagnostic approach. The entities to be considered for differential diagnosis were mainly the other classical chronic myeloproliferative neoplasms. Conclusions The Delphi method is a robust tool to determine essential information to be included in a pathology report. A standardised good-quality histopathological report form may help to homogenise PMF diagnosis. A close collaboration between the pathologist and the haematologist is desirable according to our survey.

Symptom burden in myeloproliferative neoplasms (MPNs) is heterogeneous even among patients within the same MPN diagnosis. Using cluster analysis from prospectively gathered symptom burden data in 1470 international patients with essential thrombocythemia (ET), polycythemia vera (PV), or myelofibrosis (MF), we assessed for the presence of clusters and relationship to disease features and prognosis. In MF (4 clusters identified), clusters significantly differed by Dynamic International Prognostic Scoring System (DIPSS) risk (P < .001), leukopenia (P = .009), thrombocytopenia (P < .001), and spleen size (P = .02). Although an association existed between clusters and DIPSS risk, high symptom burden was noted in some low and intermediate-1-risk MF patients. In PV (5 clusters identified), total symptom score increased across clusters (P < .001), but clusters did not significantly differ by PV risk or the risk assessment variable of age. Among ET patients (5 clusters identified), clusters differed by gender (P = .04), anemia (P = .01), and prior hemorrhage (P = .047). Total symptom score increased across clusters (P < .001), but clusters did not significantly differ by International Prognostic Score for ET risk including the risk assessment variables. Significant symptom heterogeneity exists within each MPN subtype, sometimes independent of disease features or prognosis.

We have characterized the molecular changes underlying the transformation of a JAK2V617F+-myelofibrosis with trisomy 8, into a JAK2V617F-negative leukemia. Leukemic clone did not carry JAK2V617F mutation, but showed ASXL1 mutation (R693X). This mutation was identified in a low percentage at diagnosis by next-generation sequencing. Using this technology in serial specimens during the follow-up, we observed a progressive expansion of the ASXL1-mutated minor clone, whereas the JAK2V617F+-clone carrying trisomy 8 decreased. Hematologic progression occurred simultaneously with an ASXL1-R693X-negative lung-cancer. This is the first report showing a clear association between the expansion of an ASXL1-mutated clone and the leukemic transformation of myelofibrosis.

Background We have previously reported on the high prevalence and severity of challenges with intimacy and sexuality amongst a large international cohort of MPN patients (Emanuel JCO 2012). We sought to further analyze the relationships between issues of intimacy (sexual desire and function), their relationships to MPN disease features, individual MPN symptom prevalence and severity, language, and overall quality of life. Methods Data was collected among an international cohort of patients with MPNs. Subjects completed the BFI, MPN-SAF, and EORTC QLQ-C30 instruments. Surveyed symptoms on the MPN-SAF included the patient’s perceptions of common MPN-related symptoms and overall quality of life (QOL) on a 0 (absent) to 10 (worst imaginable) scale. Specifically, the MPN-SAF sexuality item asked about “problems with sexual desire or function”. Total symptom score (TSS) was computed based on 10 symptom items using the published scoring algorithm on a 0 (all reported symptoms absent) to 100 (all reported symptoms worst imaginable) scale. Pairwise associations between the MPN-SAF sexuality item and continuous and categorical covariates were investigated using Pearson correlations and analysis of variance/t-tests, respectively. Multivariate regression models were used to investigate impact of groups of covariates on the sexuality item with the final multivariate model selected using forward regression. Results Demographics A total of 1908 MPN patients (essential thrombocythemia=799, polycythemia vera=671, myelofibrosis=432, missing=6) completed the sexuality item. Participants were of typical age (median=60, range 15-94) and gender (female=53%). Overall, 1218 subjects described sexuality related complaints (score >0) with an overall mean symptom score of 3.5 (median=2.0, SD=3.7, range 0-10); 725/1908 (38%) patients had severe sexuality related complaints (score >4). Univariate Analysis Among the QLQ-C30 functioning scales, all domains had similar statistically significant correlations (r=-.26 to -.32, all p Multivariate Analysis In a multivariate model of MPN-SAF sexuality containing all QLQ-C30 functioning scales, physical (p=0.001), emotional (p=0.01), cognitive (p=0.005) and social (p=0.002) functioning were all statistically significant. Numerous symptoms were also significant in a multivariate model of MPN-SAF sexuality containing all other MPN-SAF symptoms (all p Conclusions Sexuality related complaints have been linked to both physiologic and psychologic origins and are highly prevalent within the MPN population. The results of this study congruently identified close associations between sexuality and function within emotional, cognitive and social domains. Additionally, the correlations of sexuality issues with MPN symptoms and disease features further suggest this item is a key correlate of overall functionality and quality of life. Future investigations into the causative factors and biological correlates of this complaint may assist in addressing this ongoing challenge. Disclosures: Etienne: novartis: Consultancy, Membership on an entity’s Board of Directors or advisory committees; Bristol Myers Squibb: Consultancy, Membership on an entity’s Board of Directors or advisory committees; Pfizer: Membership on an entity’s Board of Directors or advisory committees; Ariad: Membership on an entity’s Board of Directors or advisory committees. Roy:Novartis, BMS: Honoraria. Harrison:Novartis: Honoraria, Membership on an entity’s Board of Directors or advisory committees, Research Funding, Speakers Bureau; Sanofi: Honoraria, Membership on an entity’s Board of Directors or advisory committees, Speakers Bureau; YM Bioscience: Honoraria, Membership on an entity’s Board of Directors or advisory committees; Celgene: Honoraria; Shire: Speakers Bureau; S Bio: Honoraria, Membership on an entity’s Board of Directors or advisory committees; Gilead: Honoraria, Membership on an entity’s Board of Directors or advisory committees. Birgegard:Vifor Pharma: Honoraria. Mesa:Eli Lilly and Co: Research Funding; Genetech: Research Funding; Gilead: Research Funding; Incyte: Research Funding; Sanofi: Research Funding; NS pharma: Research Funding; Celgene: Research Funding.

Background: Non-driver mutations and JAK2V617F allele burden have been involved in progression to myelofibrosis (MF) or acute myeloid leukemia (AML) in patients with polycythemia vera (PV) and essential thrombocythemia (ET). It is unknown if both mechanisms play a different role in disease transformation and if they are useful in routine clinical practice. Methods: JAK2V617F allele burden was monitored in 208 patients (PV n=106, ET n=102) for a median of 6.5 years (range: 1-13). Quantification of JAK2V617F allele burden was assessed on the first available sample and every year thereafter. The evolutionary pattern of JAK2V617F allele burden was categorized as persistently low (50%), progressive increase (> 25% from baseline) or unexplained decrease (not therapy related). Next generation sequencing (NGS) analysis of 51 myeloid-related genes was performed in 100 patients with a median molecular follow-up of 10 years including all cases with transformation to AML or MF. Detected mutations by NGS in the last sample were studied in first paired sample obtained in the chronic phase (median time from diagnosis: 1.6 years). Time to myelofibrosis and time to AML were calculated according to the presence of non-driver mutations or the JAK2V617F evolutionary pattern. Multivariate analysis was performed by Cox regression. Results: With a median follow-up of 13 years (range: 1-30) 32 patients died whereas 24 and 12 patients progressed to MF and AML, respectively. Median age at diagnosis was 63 years (range: 20-94), 115 were women (55%) and 173 (83%) received cytoreduction. A persistently low JAK2V617F allele burden was observed in 62% of patients whereas the remainder presented a persistently high (25%), a progressive increase (11%) or a non-therapy-related decrease of JAK2V617F allele burden (2%). Non-driver mutations were detected in last sample in 48% of patients. Median number of mutations was 1 (range: 1-5). Mutational frequencies were: TET2 12%, DNMT3A 12%, TP53 9%, ASXL1 7%, RUNX1 4%, SF3B1 4%, SRSF2 4%, IDH1/2 4%, SH2B3 3 % and Mutations were detected in first sample in 28% of patients (58% of those with mutations in last sample). Frequencies of mutations in first sample were: TET2 10%, DNMT3A 5%, TP53 5%, ASXL1 4%, SRSF2 4%, IDH1/2 3%, and < 2% for SF3B1, SH2B3, KMT2A and ZRSR2. The evolutionary pattern of JAK2V617F allele burden was not associated with the presence of mutations in first or last sample. Twelve patients progressed to AML (post-PV n=7, post-ET n=5), nine of them presented mutations in first sample. AML transformation at 15 years was 27% and 6.8% for patients with and without additional mutations in first sample, respectively (p=0.001). Mutated genes associated with a higher probability of AML transformation were DNMT3A (p 65 years (p=0.012) and exposure to busulfan (p=0.003). Evolutionary JAK2V617F pattern was not associated with the probability of AML (p=0.667). In multivariate analysis, an increased risk of AML transformation was observed for patients with additional mutations in the chronic phase (HR: 6.3; 95%CI 1.6-24.7, p=0.008) after adjusting for initial diagnosis, age and exposure to busulfan. Twenty-four MF transformations were documented (post-PV n= 18, post-ET n=6). Presence of additional mutations was not associated with the probability of MF (p=0.189). Patients with persistently high or a progressive increase of the JAK2V617Fallele burden showed a higher probability of MF transformation (24% versus 1.5% at 10 years, p Conclusion: Non-driver mutations are involved in the progression of PV and ET to AML but not to MF. NGS could be useful for identifying patients with PV or ET at risk of AML transformation. Acknowledgment:This work was supported by grants from the Instituto de Salud Carlos III, Spanish Health Ministry, FISPI13/00557, FISPI1300393, RD012/0036/0004, 2014 SGR567. Alicia Senín received a grant from Sociedad Española de Hematología y Hemoterapia. Disclosures No relevant conflicts of interest to declare.

BACKGROUND: Symptom burden in essential thrombocythemia (ET) and polycythemia vera (PV) is severe even among individuals with low risk disease (Blood 2012. 12;123(24):3803-10). New therapies exist which alleviate the severe symptom burden and reduce splenomegaly in ET and PV patients (N Engl J Med 2015; 372:426-435). This analysis is the first to date to evaluate thresholds at which symptom-based treatment can be considered for ET and PV patients who are intolerant or resistant to hydroxyurea (HU). METHODS: Patient demographics, symptom burden, and disease traits were collected from ET and PV patients at a single time point during therapy. The MPN-10 total symptom score (TSS, JCO 2012;30(33)4098-103) was utilized to assess symptom burden. Symptom criteria models were determined as previously described among a population of MF patients (Scherber et. al. EHA 2016: a2250). Cutoffs were then evaluated in a cohort of ET and PV patients to assess for utility as a symptom model among this population. RESULTS: Demographics and symptom burden: 838 PV and 867 ET patients with previous hydroxyurea therapy were included in this analysis. Patients were of mean age (54.9 years ET, 64.0 years PV) and gender (69.2% female ET, 55.7% female). Mean disease duration was 6.0 years for ET and 7.3 years for PV.Among ET and PV patients, 15.0% and 24.2% had prior thrombosis respectively. In evaluating prognostic risk, ET patients tended to be low (45.5%) or intermediate risk (42.9%) with only a minority of patient meeting criteria forhigh risk disease (11.6%). Laboratory findings: ET patients had a mean platelet value of 598.7x 109/L(SD=283.4). Among PV patients, mean hematocrit was 45.8% (SD=8.1) and 42.6% of patients had a hematocrit of greater than 45%. White blood cell count was normal between the two groups (ET mean 8.3 x 109/L, PV mean 9.0 x 109/L). Symptoms: Mean worst symptom severity was 6.4 out of 10 (SD=2.7). Among ET patients, worst symptom was most frequently fatigue (32.7%, mean 5.0/10, SD=3.1, overall prevalence 88%) followed by night sweats (13.6%, mean 2.0/10, SD=3.0, overall prevalence 53%) and concentration difficulties (8.6%, mean 3.1/10, SD=3.0, overall prevalence 68%). For PV, worst individual symptom items were most frequently fatigue (29.2%, mean 5.2/10, SD=3.0, overall prevalence 91%), pruritus (14.1%, mean 3.2/10, SD=3.2, overall prevalence 69%), and night sweats (12.8%, mean 2.5/10, SD=3.0, overall prevalence 57%). Cutoff Scoring: 47.0% of ET patients fit criteria for TSSgreater than to equal to 20; 59.0%% had a single itemgreater than 5; and 45.7% had both a TSS greater than or equal to 20 and a single item greater than 5. Among PV participants, 54.5% had aTSS greater than to equal to 20; 66.1% had a single itemgreater than 5; and 51.5% had both a TSS greater than or equal to 20 and a single item greater than 5. Each scoring method was significantly associated with individual item scores (Table 1). Prognostic scoring was not significantly associated with any of the symptom cutoffs evaluated. Correlations: Among ET patients, a prior history of thrombosis was significantly associated with having a worst symptom item greater than 5 (p=0.043). ET patients with lower hemoglobin were significantly more likely to meet criteria for a MPN-10 score greater than or equal to 20 or to meet combined criteria for a MPN-10 greater than or equal to 20 and single worst item greater than 5 (for both p=0.01 or less). For PV, lower hematocrit levels were significantly associated with having an individual worst symptom score of greater than 5 (44.9% versus 46.7%, p=0.0376). CONCLUSION: Assessment of ET and PV symptoms, now measurable through standardized and practical instruments such as the MPN-10, is an integral part of determining therapeutic impact of newer therapies in both clinical practice and trial settings. In our modeling, patients with severe symptom burden profiles are well represented by utilizing cutoff criteria including aworst individual symptom item of greater than 5 out of 10, an MPN-10 score of greater than or equal to 20, or combined criteria of both cutoffs. These cutoffs can be considered when determiningwhich HU intolerant or resistant patients would most benefit fromsymptom orientedtreatment. Disclosures Kiladjian: AOP Orphan: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Honoraria, Research Funding. Schouten:Novartis: Consultancy; Sanofi: Consultancy. Etienne:BMS: Speakers Bureau; ARIAD: Speakers Bureau; Pfizer: Speakers Bureau; novartis: Consultancy, Speakers Bureau. Harrison:Incyte Corporation: Honoraria, Speakers Bureau; Shire: Honoraria, Speakers Bureau; Gilead: Honoraria, Speakers Bureau; Baxaltra: Consultancy, Honoraria, Speakers Bureau; Novartis: Consultancy, Honoraria, Other: travel, accommodations, expenses, Research Funding, Speakers Bureau. Radia:Pfizer: Honoraria; Novartis: Honoraria. Cervantes:AOP Orphan: Membership on an entity's Board of Directors or advisory committees; Baxalta: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Novartis: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Vannucchi:Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau. Mesa:Promedior: Research Funding; Celgene: Research Funding; CTI: Research Funding; Gilead: Research Funding; Incyte: Research Funding; Galena: Consultancy; Ariad: Consultancy; Novartis: Consultancy.

BACKGROUND: The presence of constitutional symptoms has been associated with increased mortality risk in myelofibrosis (MF) (Blood 2010;115(9):1703-8). New therapies exist which alleviate the severe symptom burden profile observed in MF patients but are only approved for use in those with intermediate-2 or high risk disease (N Engl J Med 2012;366:787-798). However, it has been proposed that there are patients who may benefit from symptom based treatment regardless of prognostic score (Am Soc Hematol Educ Program 2014;2014:277-286). We have recently characterized symptom score cutoffs at which patients would statistically benefit from treatment based on symptom scores alone (Scherber et. al. EHA 2016: a2250). These treatment thresholds included aMyeloproliferative Neoplasm Symptom Assessment Form Total Symptom Score (MPN-SAF TSS or MPN-10) total score of greater than or equal to 20, a worst individual item score of greater than 5, or a combined criteria of those with both an MPN-10 total score of greater than or equal to 20 and a worst individual item score greater than 5. This abstract represents an additional analysis of our MF cohort to better characterize the profile of patients who meet criteria for symptom-based therapy. METHODS: Patient demographics, symptom burden via the MPN-10 score (JCO 2012;30(33)4098-103), and disease traits were collected from MF patients and their physicians at a single time point during therapy. Previously we identified MPN-10 cutoffs via AkaikeÕs Information Criterion (AIC) analysis (Ecology 2014;95: 631-6), which represented the optimal model among all models specified for the data at hand to determine which patients would most benefit from symptom-directed therapy. RESULTS: Demographics. 695 MF patients without previousruxolitinib therapy were included in this analysis. Overall, of 455 patients (65.4%) fit a cutoff of having a single worst symptom item of greater than 5/10. 401 patients (57.7%) had a MPN-10 score of equal to or greater than 20. A total of 381 (54.8%) patients fit both of these criteria. A distribution of worse MPN-10 individual scores is shown in Table 1. Mean TSS score was 26.4 (SD=17.7). Symptom Criteria Associations. Demographics and disease traits: Neither mean age or age greater than 60 was significantly associated with meeting any of the symptom score cutoff criteria. Females were significantly more likely to meet any of the symptom score cutoffs (for all criteria, p=0.0003 or less). Patients with splenomegaly, particularly spleen size of greater than 15cm below the LCM, were significantly more likely than those with a normal sized spleen to meet any of the three criteria (spleen enlargement of any size p=0.014 or less; spleen greater than 15cm p=0.0114 or less). Patients who met any of the three symptom criteria tended to have a longer MPN duration, although this trend did not meet significance. A prior history of thrombosis was not associated with achieving any cutoff criterions. Symptom burden: Individuals who met the any symptom criteria were significantly more likely to have higher DIPSS prognostic risk score (for all p=0.0002 or less). Laboratory values: For those meeting criteria for a worst symptom greater than 5, mean WBC was 11.7 vs 9.1 x 109/L (p=0.025) and platelet count was 238.7 versus 329.1 (p=0.023). For those meeting criteria for a TSS greater than or equal to 20, mean WBC was 11.8 vs 9.5 x 109/L (p=0.04). For individuals meeting both criteria, mean WBC was 11.9 vs 9.5 x 109/L (p=0.034). The presence of peripheral blasts were significantly more common in patients with an individual worst symptom score greater than 5 (p=0.0364). Hemoglobin level was not significantly associated with symptom criteria for any cutoffs. CONCLUSION: Our analysis indicates that patients who would be treated based on symptom criteria are similar to patients who would be treated based on high risk features such as high DIPSS prognostic score, concerning blood count abnormalities (i.e., leukocytosis, thrombocytopenia, presence of peripheral blasts), and splenomegaly (particularly massive splenomegaly). Thrombosis history and age were not associated with criterion cutoff assignment, and it is notable that elderly age nor history of thrombosis alone would likely alter treatment choice other than anticoagulation. This data supports that JAK2 inhibitor treatment be strongly considered in patients meeting symptom based criteria. Disclosures Dueck: Bayer: Honoraria. Kiladjian:Novartis: Honoraria, Research Funding; AOP Orphan: Membership on an entity's Board of Directors or advisory committees, Research Funding. Zweegman:Celgene: Honoraria, Research Funding; Janssen: Honoraria, Research Funding; Takeda: Honoraria, Research Funding. Schouten:Sanofi: Consultancy; Novartis: Consultancy. Etienne:ARIAD: Speakers Bureau; Pfizer: Speakers Bureau; novartis: Consultancy, Speakers Bureau; BMS: Speakers Bureau. Harrison:Shire: Honoraria, Speakers Bureau; Gilead: Honoraria, Speakers Bureau; Baxaltra: Consultancy, Honoraria, Speakers Bureau; Incyte Corporation: Honoraria, Speakers Bureau; Novartis: Consultancy, Honoraria, Other: travel, accommodations, expenses, Research Funding, Speakers Bureau. Radia:Novartis: Honoraria; Pfizer: Honoraria. Cervantes:Novartis: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Baxalta: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; AOP Orphan: Membership on an entity's Board of Directors or advisory committees. Vannucchi:Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau. Mesa:Promedior: Research Funding; Celgene: Research Funding; CTI: Research Funding; Gilead: Research Funding; Incyte: Research Funding; Galena: Consultancy; Ariad: Consultancy; Novartis: Consultancy.

INTRODUCTION Chemotherapy-induced hepatitis B virus (HBV) reactivation is a well-recognized complication and is a potentially life-threatening condition in cancer patients with chronic HBV (hepatitis B surface antigen [HBsAg]-positive). Rituximab has been associated with an increase in HBV reactivation in chronic HBV patients (45%) and even in patients with resolved infection (HBsAg negative and hepatitis B core antibody [anti-HBc]-positive (22%); however, the reported frequency varies among different studies. Current guidelines for management of chronic HBV recommend routine antiviral HBV prophylaxis with lymphoma before starting chemotherapy. In contrast, there is little evidence-based consensus regarding patients with resolved HBV infection. Aim: To analyze the incidence of HBV reactivation and the role of antiviral HBV prophylaxis in lymphoma patients with chronic HBV or resolved HBV treated with chemotherapy, immunotherapy or immunochemotherapy managed according to our institutional HBV guidelines. Secondary endpoints were to analyze the incidence of HBV in this population and HBV guidelines adherence. PATIENTS AND METHODS Lymphoma patients with chronic HBV or resolved HBV in a single center. HBV viral status definitions: Active Chronic HBV infection: HBsAg positive, anti-HBc positive and HBV DNA >2000 IU/mL; Inactive Carriers: HBsAg positive, Anti-HBc positive, HBV DNA undetectable or HBV reactivation was defined as increased serum HBV DNA (≥1 log10), regardless of liver biochemistry or HBsAg status. Institutional HBV guidelines: serum samples were collected at baseline for HBsAg and anti-HBc testing in all lymphoma patients. Patients were evaluated by a hepatologist if any of them fulfilled HBV viral status definition. Baseline at screening and monitoring every 3 months during therapy and up to 24 months after completing therapy (assessment of liver biochemistry, serum HBV DNA, HBsAg and anti-HBs levels). Specific prophylaxis strategies according to HBV status: Group A (Active chronic HBV): treatment for HBV; Group B (Inactive carriers): antiviral HBV prophylaxis; Group C (Resolved HBV): antiviral HBV prophylaxis if rituximab containing-therapy or follow-up only if rituximab-free therapy. HBV antiviral prophylaxis was started before therapy and finished 12 months after completing therapy. RESULTS From January 2012 to January 2015, 227 lymphoma patients received chemotherapy or immunochemotherapy. 142 (63%) patients received rituximab-containing therapy. 43 (19%) patients were anti-HBc positive. Group A: 2 (1%) patients; Group B: 2 (1%) patients; Group C: 39 (17%) patients. 14 (6%) patients have coinfection with hepatitis C virus and 12 (5%) patients co-infection with human immunodeficiency virus (HIV). Adherence to HBV guidelines was 90%. Patients in Group A (n=2) and B (n=2) received antiviral treatment/prophylaxis before starting therapy. In the Group C, 16 (41%) patients underwent only follow-up and 23 (59%) patients received HBV antiviral prophylaxis (lamivudine in 4, entecavir in 8 and tenofovir in 11). Median duration of HBV prophylaxis was 18 months (95% CI: 16-19 months). After a median follow-up of 21 months, 2 patients developed HBV reactivation during lymphoma treatment: 1 from group B (reactivation rate of 50%) and 1 from group C (reactivation rate of 3%). Both patients had received rituximab-containing treatment and both developed HBV reactivation (without hepatitis flare) within the first 6 months after finishing antiviral HBV prophylaxis (delayed HBV reactivation). Outcome was favorable in both patients. Characteristics of HBV reactivation patients are shown in table I. Cumulative incidence of HBV reactivation at 12 and 24 months were 0% and 8%, respectively. CONCLUSION Our strategy of close monitoring patients with chronic HBV or resolved HBV that receive chemotherapy and adding antiviral HBV prophylaxis only in selected patients clearly decrease HBV reactivation. Nevertheless, this strategy may not fully protect patients from late HBV reactivations. Larger validation studies are needed to confirm our data and to establish the best cost-effective strategy in this lymphoma population, especially in the new era of inmunomodulatory drugs of their real involvement in HBV reactivation is unknown. Table 1 Table 1. Disclosures No relevant conflicts of interest to declare.

Abstract 1731 Background: Symptom burden in primary, post-ET and post-PV myelofibrosis (MF) is frequently severe and correlates with a poor prognosis. However, symptom manifestations are heterogeneous with variable presence of specific symptoms, splenomegaly and cytopenias. We sought to identify the spectrum and features of MF symptomatic phenotypes by cluster analysis of prospectively gathered information on MF symptoms and disease features. Methods: Data was collected among an international cohort of subjects with MF. Data included demographics, disease features and completion of the Brief Fatigue Inventory (BFI) and Myeloproliferative Neoplasm Symptom Assessment Form Total Symptom Score (MPN-SAF TSS) (Blood 2011; 118:401–408). Surveyed symptoms addressed key disease features on a 0 (absent) to 10 (worst-imaginable) scale. Cluster development was based on consideration of r-squared in hierarchical clustering using Ward's linkage. Final cluster assignment was based on the nonhierarchical k-means method. Comparisons between symptom clusters were based on ANOVA and chi-squared tests. Results: Subject Demographic and Disease Characteristics: Data from 329 prospectively enrolled persons with MF was collected (Chinese 102, French 54, German 19, Italian 22, Dutch 45, English 51, Spanish 29, Swedish 7) including 223 PMF, 67 post-ET MF and 39 post-PV MF patients. Participants were of typical age (mean 59) and gender (47% F). Among all participants, four natural symptom clusters were identified (Figure 1). Among clusters, disease features including leukopenia, thrombocytopenia, and enlarged spleen varied significantly between clusters (P Cluster 1: The “Fatigue Dominant with Few Lab Abnormalities” Profile (n=150 (46%; 69% PMF, 20% post-ET MF, 11% post-PV MF)). Cluster 1, the largest, is characterized by fatigue-dominant complaints in the setting of the lowest overall MPN-SAF TSS and highest proportion of males (59%). Individuals among this group have the lowest prevalence of laboratory abnormalities (65% total; anemia, 67%; thrombocytopenia, 20%) or clinical deficiencies including enlarged spleen (average 6.0 cm below costal margin), prior thrombosis (9%), prior hemorrhage (5%) or prior RBC-transfusions (20.4%). Interestingly, individuals in this group are most likely to have had prior splenectomy (5.8%). Cluster 2: The “Cognitive Complaints with Enlarged Spleen” Cluster (n=105 (32%; 65% PMF, 20% post-ET MF, 15% post-PV MF)). Cluster 2 is the 2nd largest cluster. Subjects have relatively few abnormal lab values (67% vs 65%–77%) but have high severity of fatigue, sexual difficulties, insomnia, inactivity and reduced QOL. These individuals have the largest spleen size (8.7cm below costal margin). Cluster 3: The “Nighttime and Cognitive Complaints” Group (n=53 (16%; 64% PMF, 25% post-ET MF, 11% post-PV MF)). Cluster 3 is the smallest cluster. Subjects have many cognitive and nighttime-related complaints including sexual difficulties, night sweats, insomnia, and concentration problems. Subjects with post-ET MF are predominant. This cluster also has the 2ndsmallest spleen size (7 cm) or history of prior thrombosis (9.6%), hemorrhage (7.8%) or requirement for transfusions (21.2%). Cluster 4: The “Severe Fatigue with Few End-organ Complaints” Cluster (n=21 (6%; 81% PMF, 14% post-ET MF, 5% post-PV MF)). Cluster 4 is the most symptomatic cohort with the highest proportion of subjects with PM. There is a lower frequency of end-organ complaints including abdominal pain, cough, and headaches. Symptoms including sexual difficulties, sad mood and insomnia are predominant. No subjects had prior splenectomy. Subjects also have the highest prevalence of prior thrombosis (29%), hemorrhage (14%), and transfusions (43%). Additionally, this cohort has the largest prevalence of lab abnormalities (77%) with thrombocytopenia (71%), leukopenia (41%) and anemia (41%). Conclusion: This analysis will allow us to examine a new framework for evaluating persons with MF using symptom profiles and is the 1st cluster evaluation of MF. Lab and physical findings contrast significantly between symptom clusters indicating these phenotypic symptoms likely result from etiological factors present in specific disease phenotypes. Future studies should evaluate whether there is a correlation between cluster profiles, prognosis and genotype. Disclosures: Kiladjian: Celgene: Research Funding; Novartis: Honoraria, Research Funding; Shire: Honoraria. Roy:Novartis, BMS: Speakers Bureau. Harrison:Novartis: Honoraria, Research Funding, Speakers Bureau; YM Bioscience: Consultancy, Honoraria; Sanofi Aventis: Honoraria; Shire: Honoraria, Research Funding. Vannucchi:Novartis: Membership on an entity's Board of Directors or advisory committees. Passamonti:Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Sanofi: Honoraria, Membership on an entity's Board of Directors or advisory committees. Mesa:Incyte: Research Funding; Lilly: Research Funding; Sanofi: Research Funding; NS Pharma: Research Funding; YM Bioscience: Research Funding.