Management Of Myeloproliferative Neoplasms Research Articles

Pregnancy Outcomes in Patients with Myeloproliferative Neoplasms in the United Kingdom

IntroductionPhiladelphia negative myeloproliferative neoplasms (MPNs) are associated with an increased incidence of haemorrhagic and thromboembolic complications as well as progression to myelofibrosis and acute myeloid leukaemia. MPNs have a peak incidence in 6th and 7th decade of life. However, they can occur in younger age groups and women of child bearing age.Pregnant women with MPN are at an increased risk of maternal thrombosis and haemorrhage and also of impaired uterine blood flow, placental dysfunction, fetal growth restriction, pre-term delivery and fetal loss. There are no prospective studies of pregnancy outcome in the literature.MethodA national prospective cohort was established to describe the maternal and fetal outcomes of pregnancy in women with MPN in the United Kingdom (UK). Data were collected using the UK Obstetric Surveillance System (UKOSS) between January 2010 and December 2012 (UKOSS methodology described by Knight et al, 2005). UK hospitals with a consultant led maternity unit identified pregnant woman with a MPN and provided detailed data on antenatal, maternal and fetal outcomes. Pregnancy outcome data were compared with that reported by the UK Office of National Statistics (ONS) in 2011.Results58 women were identified: 47 with Essential Thrombocythaemia (81%), 5 with Polycythaemia Vera (8.6%), 5 with Myelofibrosis (8.6%) and 1 with JAK2 positive MPN unspecified (1.7%). The incidence of MPN in pregnancy was 6.4/100,000 maternities.The median age was 33 years (range 16-42), compared to average national age during 2011 of 29.7 years. There were 58 live births (56 singleton, 2 twin), one miscarriage and one stillbirth (at 37 weeks) with a miscarriage rate of 1.8% and the perinatal mortality rate of 17/1000 live and stillbirths. The national rates reported by ONS in 2011 were 6.4 miscarriages/100 pregnancies and of 5.2 stillbirths/1000 live and stillbirths. The incidence of pre-eclampsia was 8.8% (n=5/57), compared to 3.4% as reported by Ananth et al 2013. The majority 78.9% (n = 45/57) of women laboured; 42.1% (n = 24/57) underwent induction and spontaneous vaginal delivery occurred in 39% (n = 22/57) of women. Caesarean section (CS) was performed in 42.1% (n = 24/57). Most of the caesareans were performed pre-labour, with an elective CS rate of 24.6% (n = 14/57), and emergency CS rate of 17.5% (n = 10/57). The UK average CS rate in 2011 was 24.8%.Most (86%; 49/57) women delivered at term (>37 weeks). The incidence of preterm (< 37 weeks) and very preterm (<32 weeks) birth was 7.0% (n = 4/59) and 3.5% (n =2/59) respectively; ONS 2011 UK averages were 10.7% and 5.3% respectively. The median birth weight was 3150g (range 720 - 4700g); 13.6% (n = 8/59) of neonates had a low birth weight (<2500g) and 5.1% (n=3) had a very low birth weight (<1500g). 5% of births in 2011 were documented to be below 2500g according to ONS.There was considerable variation amongst clinicians in the management of MPNs. Only 50% (n = 29/58) of women were in receipt of aspirin therapy prior to the index pregnancy. This increased during pregnancy with over 88% (n = 51/58) prescribed aspirin; 38% (n = 22/58) were on both aspirin and low molecular weight heparin. Cytoreductive therapy was used in 43% (n=25/58) of the women prior to index pregnancy (including hydroxyurea (HU), anagrelide (ANA) and interferon). During the index pregnancy, 7 women continued cytoreductive therapy, switching to interferon when prior HU or ANA were used. One woman with ET was initiated on interferon.ConclusionThis first prospective analysis of maternal and fetal outcomes in women showed an incidence of MPN in pregnancy of 6.4/100,000 maternities which is consistent with previous reports. The increased occurrence of pre-eclampsia and fetal growth restriction might explain the higher rates of induction and caesarean section. The majority (87%) of babies were delivered at term.Although this was a small sample, it was reassuring there were no maternal deaths or admissions to intensive care, and only one perinatal death, as previous retrospective data has reported worse outcomes. The clinician variability in the approach to the management of women with MPNs in pregnancy suggests further improvements may be possible. DisclosuresHarrison:Shire: Speakers Bureau; Novartis: Honoraria, Research Funding, Speakers Bureau; Sanofi: Honoraria, Speakers Bureau; Gilead: Honoraria; CTI Biopharma: Consultancy, Honoraria, Speakers Bureau.

Targeting phosphatidylinositol-3-kinase pathway for the treatment of Philadelphia-negative myeloproliferative neoplasms.

Myeloproliferative neoplasms (MPN) are a diverse group of chronic hematological disorders that involve unregulated clonal proliferation of white blood cells. Sevearl of them are associated with mutations in receptor tyrosine kinases or cytokine receptor associated tyrosine kinases rendering them independent of cytokine-mediated regulation. Classically they have been broadly divided into BCR-ABL1 fusion + ve (Ph + ve) or –ve (Ph-ve) MPNs. Identification of BCR-ABL1 tyrosine kinase as a driver of chronic myeloid leukemia (CML) and successful application of small molecule inhibitors of the tyrosine kinases in the clinic have triggered the search for kinase dependent pathways in other Ph-ve MPNs. In the past few years, identification of mutations in JAK2 associated with a majority of MPNs raised the hopes for similar success with specific targeting of JAK2. However, targeting JAK2 kinase activity has met with limited success. Subsequently, mutations in genes other than JAK2 have been identified. These mutations specifically associate with certain MPNs and can drive cytokine independent growth. Therefore, targeting alternate molecules and pathways may be more successful in management of MPNs. Among other pathways, phosphatidylinositol −3 kinase (PI3K) has emerged as a promising target as different cell surface receptor induced signaling pathways converge on the PI3K signaling axis to regulate cell metabolism, growth, proliferation, and survival. Herein, we will review the clinically relevant inhibitors of the PI3K pathway that have been evaluated or hold promise for the treatment of Ph-ve MPNs.

JAK2V617F: Is It Sufficient as a Single Player in Splanchnic Venous Thrombosis?

Splanchnic venous thrombosis (SVT) includes thrombosis of the hepatic, portal, and mesenteric venous system. Myeloproliferative neoplasms (MPNs) are important factors of SVT in adults. Addition of JAK2V617F mutation in WHO criteria for diagnosis of MPNs has made this test a useful tool for diagnosis. JAK2 is an intracytoplasmic tyrosine kinase that plays a critical role in signal transduction from multiple hematopoietic factor receptors. The mutation is found frequently in patients with SVT; many such patients have no other manifestations of an MPN. Although the correlation of JAK2V617F mutation with thrombotic risk in MPNs has been shown in many studies, the impact of presence of additional thrombophilic factors in these cases is yet not known. As the management of MPNs remains highly dependent on the patient's thrombotic risk, it is important to assess the thrombotic risk factors in detail. Here, we report two cases of JAK2V617F positive MPN who also had other thrombophilic conditions and presented with recurrent thrombosis.

On the Absence of Calreticulin (CALR) Mutations in Chronic Myeloprolierative Neoplasms (MPNs) with Splanchnic Venous Thrombosis (SVT): Experience from a Single Institution

Background: According to recent findings, the management of myeloproliferative neoplasms (MPNs) is highly dependent on presence or absence of thrombotic events. The JAK2 mutation has been identified as a marker of MPNs. It is also an occult marker in several patients with splanchnic venous thrombosis (SVT), but its contribution as an additional thrombotic risk factor in MPNs is still under discussion. Moreover, a pro-thrombotic risk factor, either inherited or acquired (Factor V Leiden mutation, deficiencies in protein C, protein S and Prothrombin mutation 20210) can be identified in these patients. Recently, another milestone in the molecular diagnosis of MPNs, somatic mutations in the CALR gene, has been reported. A total of 36 types of frame-shifting insertions and deletions were detected in the exon 9 of CALR gene, which encodes a Ca2+ binding protein in endoplasmic reticulum called calreticulin. Type-1, 52-bp deletion (p.L367fs*46), and type-2, 5-bp TTGTC insertion (p.K385fs*47) variants constitute more than 80% of these mutations These mutations were reported to have a incidence of over 60% to 80% in JAK2 and MPLmutation-negative Essential Thrombocythemia (ET) and Primary Myelofibrosis (PMF) patients. Compared to those with JAK2 mutation, CALR-mutated ET patients are younger and have a lower leukocyte count and higher platelet count. CARL mutations have been also reported as a favorable prognostic factor on thrombosis-free survival (TFS) for ET patients.Aims: In this study, we evaluated the incidence of SVT, JAK2 and CALR mutations, and prothrombotic risk factors in patients with MPNs observed in our center from January 2000 to January 2014.Methods: We performed a retrospective review of clinical charts of 466 Ph1 negative MPN patients followed in our center, classified according to the WHO 2008 classification. Patient and disease characteristics, including JAK2V617F, MPL and CALR mutations and thrombotic risk factors were recorded.Results: The median age of patients with diagnosis of MPN was 43 years. Fourteen patients (13 females, 1 male; 3%) of median age 46 years presented a SVT. Three had a Budd Chiari syndrome and 11 a portal venous thrombosis. According to a histological review, these patients were classified as follows: ET, 2 cases, PMF, 3 cases, Polycythemia Vera (PV) 1 case, Myelofibrosis in a prefibrotic phase (MF0) 8 cases. Classification of 11 cases with Myelofibrosis according to the IPSS identified 7 as INT1, 1 as INT2 and 3 as low risk. Among all 14 patients diagnosed with SVT, 12 were JAK2V617F positive with a median allelic burden of 30%, 1 patient was MPL positive, and 1 patient was triple-negative. CALR mutation was not observed in any of the patients. Two cases were diagnosed with MPN 30 months after SVT, 3 patients experienced SVT after a median follow-up of 108 months from MPN diagnosis while in 9 patients the diagnosis of MPN was concomitant to SVT. In the latter patients, median Hb levels were 12.4 g/dL , WBC 8260 /µL, HCT 36.3%, PLT 337.000/ µL and a modest hepatomegaly and splenomegaly were documented. Prothrombotic risk factors were found in 9 of 13 patients. Two patients experienced a thrombotic episode prior to the diagnosis of SVT and two subsequently during the follow-up. Interestingly, 9 (70%) of MPN patients with SVT exhibited at least one prothromobtic risk factor, such as factor V Leiden, Protein C deficiency, hyperhomocystinemia and 50% had two or more associated defects. Thirteen of the 14 patients are currently being treated as follows hydroxyurea (9), interferon (1), and ruxolitinib (3). All patients received oral anticoagulant treatment except for three who are on antiplatelet therapy. MPN patients without SVT had a lower prevalence of prothrombotic risk factors and developed venous thrombosis in different anatomical sites: in these cases WBC count, platelet values and the presence of JAK2V617F mutation correlated with the development of the thrombotic event.Conclusions: Although SVT has a low incidence in MPN patients, a potential benefit of testing for mutations in CALR gene and for additional prothrombotic risk factors is suggested in the whole MPN population for the prevention and treatment of this complication. DisclosuresNo relevant conflicts of interest to declare.

Phase 1 Study Results of a Novel Controlled-Release Formulation of Anagrelide (GALE-401) for the Treatment of Thrombocytosis

Introduction: Despite recent advances in the diagnosis and management of myeloproliferative neoplasms (MPNs), treatment of essential thrombocythemia (ET) has remained largely unchanged since the introduction of anagrelide in the US during 1997. Anagrelide is indicated for the treatment of thrombocythemia, to reduce the elevated platelet count and risk of thrombosis, and to ameliorate symptoms including thrombohemorrhagic events. The primary pharmacological effect of anagrelide is inhibition of megakaryocyte hypermaturation leading to reduced platelet production. Anagrelide also inhibits cyclic AMP phosphodiesterase III (PDE3), and common drug related adverse events (AEs; e.g., headache, palpitations, fluid retention, nausea and diarrhea) are believed to be due to this mechanism. Although initiating treatment at low doses and slowly increasing the dose to reach a target decreased platelet count may mitigate AEs, over 20% of patients still withdraw from treatment due to poor tolerability. As the currently marketed anagrelide product is an immediate release (IR) formulation with peak plasma concentrations (Cmax) that may exceed that needed for platelet reduction and cause unwanted PDE3 inhibition and AEs, an alternate formulation that modifies this pharmacokinetic (PK) profile may improve patient tolerability, adherence and treatment outcomes. This has led to the development and study of a controlled-release (CR) formulation of anagrelide (GALE-401).Methods: 98 healthy adult subjects were enrolled among 5 Phase 1 clinical trials of anagrelide CR, including 12 placebo-control subjects and 86 subjects who received single or multiple doses ranging from 0.2 to 0.6 mg twice daily (b.i.d.) for up to 41 days. The trials included an open-label, single dose developmental study; two placebo-controlled multiple dose ranging studies; a food effect study; and a comparative crossover PK study vs. IR reference product. Safety parameters included routine laboratory, ECG, and clinical evaluations. PK was assessed by measurements of plasma anagrelide and its active metabolite using a validated HPLC-MS/MS method. Pharmacodynamic activity was assessed by daily platelet count determinations in the multiple dosing studies.Results: Single doses of anagrelide CR were well tolerated, and the only drug-related AE reported in 2 or more subjects was headache. In the b.i.d. dose-ranging studies, the frequency and severity of AEs were similar between anagrelide CR and placebo groups, with the exception of decreased platelet counts in subjects receiving anagrelide CR. All AEs were transient, mild or moderate in severity, and no severe or serious AEs were reported.Anagrelide CR demonstrated dose proportional PK characteristics. Following a single 0.5 mg dose in the fasted state, the mean time to maximum plasma concentration (Tmax) and terminal elimination half-life (t1/2) were 2.0±1.5 hrs and 10.4±9.3 hrs (mean ± SD), respectively; in contrast, Tmax and t1/2 following IR was 1.0±0.9 hrs and 1.4±0.2 hrs, respectively. Cmax and total plasma exposure (AUC0-inf) with anagrelide CR were reduced to 26% and 59% of IR, respectively. However, steady-state PK following 6 daily 0.5 mg b.i.d. doses of anagrelide CR or IR showed similar AUC0-inf values, while Cmax with anagrelide CR remained nearly unchanged (29%). Plasma exposure was higher when anagrelide CR was administered in the fed state, as demonstrated by the ratio of least-squares mean values for Cmax and AUC0-t, which were increased by 100% and 60%, respectively.The platelet lowering effect of anagrelide CR was evident in the 2 multiple dose ranging studies. In a placebo-controlled study of 0.2 to 0.6 mg b.i.d. dosing for up to 21 days, a dose-related decrease in platelet counts was observed, and the 0.6 mg cohort was halted early due to excessive platelet reductions. Anagrelide CR did not have a relevant impact on platelet function as assessed by template bleeding time. [Display omitted] Conclusion: Anagrelide CR is a promising, novel formulation of anagrelide that exhibited the desired PK profile of a significantly reduced Cmax, while maintaining plasma exposure to induce platelet count reductions. The product was well tolerated with an AE profile that was not distinguishable from placebo. These data support the importance of an ongoing Phase 2 study in patients with MPN-related thrombocytosis, including ET. DisclosuresLaliberte:Galena Biopharma, Inc.: Employment, Equity Ownership. Glidden:Galena Biopharma, Inc.: Consultancy, Equity Ownership, Patents & Royalties. Hamilton:Galena Biopharma, Inc.: Employment, Equity Ownership.

Myeloproliferative neoplasms: JAK2 signaling pathway as a central target for therapy.

The discovery of the JAK2V617F mutation followed by the discovery of other genetic abnormalities allowed important progress in the understanding of the pathogenesis and management of myeloproliferative neoplasms (MPN)s. Classical Breakpoint cluster region-Abelson (BCR-ABL)-negative neoplasms include 3 main disorders: essential thrombocythemia (ET), polycythemia vera (PV), and primary myelofibrosis (PMF). Genomic studies have shown that these disorders are more heterogeneous than previously thought with 3 main entities corresponding to different gene mutations: the JAK2 disorder, essentially due to JAK2V617F mutation, which includes nearly all PVs and a majority of ETs and PMFs with a continuum between these diseases and the myeloproliferative leukemia (MPL) and calreticulin (CALR) disorders, which include a fraction of ET and PMF. All of these mutations lead to a JAK2 constitutive activation. Murine models either with JAK2V617F or MPLW515L, but also with JAK2 or MPL germ line mutations found in hereditary thrombocytosis, have demonstrated that they are drivers of myeloproliferation. However, the myeloproliferative driver mutation is still unknown in approximately 15% of ET and PMF, but appears to also target the JAK/Signal Transducer and Activator of Transcription (STAT) pathway. However, other mutations in genes involved in epigenetics or splicing also can be present and can predate or follow mutations in signaling. They are involved either in clonal dominance or in phenotypic changes, more particularly in PMF. They can be associated with leukemic progression and might have an important prognostic value such as additional sex comb-like 1 mutations. Despite this heterogeneity, it is tempting to target JAK2 and its signaling for therapy. However in PMF, Adenosine Tri-Phosphate (ATP)-competitive JAK2 inhibitors have shown their interest, but also their important limitations. Thus, other approaches are required, which are discussed in this review.

Antiplatelet Therapy in the Management of Myeloproliferative Neoplasms

Low-dose acetylsalicylic acid (ASA) is given to most patients with polycythemia vera (PV) and essential thrombocythemia (ET) although some uncertainties encompass this clinical practice. In patients with history of thrombosis, the use of ASA is supported on the results observed in the general population showing a substantial net benefit of this treatment in preventing thrombosis. In the European collaboration study on low-dose aspirin in polycythemia vera (ECLAP), ASA reduced the risk of thrombosis without increasing the risk of major bleeding when compared with placebo, supporting the primary prevention of thrombosis in PV. In ET, the efficacy of low-dose ASA has not been tested in randomized clinical trials. Two retrospective studies have shown that low-dose ASA could benefit ET patients older than 60 years when combined with cytoreduction, whereas in young, low-risk patients, ASA benefits to particular subgroups of patients. In spite of the fact that in primary myelofibrosis the incidence of thrombosis is increased, the use of ASA is not clearly recommended.

The Importance of Identification of M-BCRABL Oncogene and JAK2V617F Mutation in Myeloproliferative Neoplasms

Abstract Background: The elucidation of the genetic background of the myeloproliferative neoplasms completely changed the management of these disorders: the presence of the Philadelphia chromosome and/or the BCR-ABL oncogene is pathognomonic for chronic myeloid leukemia and identification of JAK2 gene mutations are useful in polycytemia vera (PV), essential thrombocytemia (ET) and myelofibrosis (PMF). The aim of this study was to investigate the role of molecular biology tests in the management of myeloproliferative neoplasms. Materials and methods: We tested the blood samples of 117 patients between April 2008 and February 2013 at the Molecular Biology of UMF Târgu Mureș using RQ-PCR (for M-BCR-ABL oncogene) and/or allele-specific PCR (for JAK2V617F mutation). Results: Thirty-two patients presented the M-BCR-ABL oncogene, 16 of them were regularly tested as a follow-up of the administered therapy: the majority of chronic phase patients presented decreasing or stable values, while in case of accelerated phase and blast phase the M-BCR-ABL values increased or remained at the same level. Twenty patients were identified with the JAK2V617F mutation: 8 patients with PV, 4 with ET, 3 with PMF, 4 with unclassifiable chronic myeloproliferative disease and 1 patient with chronic myelomonocytic leukemia. There was no case of concomitant occurance of both molecular markers. Conclusions: Molecular biology testing plays an important role in the management of myeloproliferative neoplasms: identification of the molecular markers confirms the final diagnosis, excluding secondary causes of abnormal blood count parameters. Regular monitoring of MBCR- ABL expression level is useful in the follow-up of therapeutic efficiency.

Management of Myeloproliferative Neoplasms: From Academic Guidelines to Clinical Practice

Myeloproliferative neoplasms (MPNs) are clonal disorders characterized by excessive production of mature cells. In most of the classic Philadelphia-negative MPNs-polycythemia vera (PV), essential thrombocythemia (ET), and MPN-associated myelofibrosis (MPN-MF)-oncogenic mutations affecting JAK2 or MPL lead to constitutive activation of cytokine-regulated intracellular signalling pathways. The traditional therapy for PV and ET is the prevention of thrombotic events with antiproliferative agents in association with aspirin. New drugs such as pegylated interferon and anti-JAK agents are candidates for slowing the evolution to myelofibrosis or leukemia. Conventional therapy for MPN-MF is driven by clinical needs, primarily anemia and splenomegaly. Lenalidomide and pomalidomide are new candidates for treating anemia. JAK2 ATP-competitive inhibitors or drugs that indirectly inhibit the JAK-STAT pathway, like RAD001, are the new candidates for splenomegaly in MPN-MF, but in spite of their strong rationale, they have shown only a palliative benefit. Allogeneic stem cell transplantation remains the only potentially curative approach.

JAK2 gene mutation: impact on pathogenesis, classification, and management of myeloproliferative neoplasms

JAK2 gene mutation: impact on pathogenesis, classification, and management of myeloproliferative neoplasms

Advances in Understanding and Management of Myeloproliferative Neoplasms

According to the 2008 World Health Organization classification system for hematologic malignancies, the myeloproliferative neoplasms (MPN) include chronic myelogenous leukemia, polycythemia vera, essential thrombocythemia, primary myelofibrosis, mastocytosis, chronic eosinophilic leukemia-not otherwise specified, chronic neutrophilic leukemia, and "MPN, unclassifiable." All of these clinicopathologic entities are characterized by stem cell-derived clonal myeloproliferation, and their phenotypic diversity is ascribed to the occurrence of distinct oncogenic events. In the last 4 years, new JAK2 and MPL mutations have been added to previously described ABL and KIT mutations as molecular markers of disease in MPN. These discoveries have markedly simplified the approach to clinical diagnosis and have also provided molecular targets for the development of small-molecule drugs. In the current article, the authors provide a clinically oriented overview of MPNs in terms of their molecular pathogenesis, classification, diagnosis, and management.