Citations

Polycythemia vera (PV) is currently diagnosed by the World Health Organization (WHO) criteria regarding hemoglobin (HB) levels and JAK2V617F and related mutations or by the British Committee for Standards in Haematology (BCSH) guidelines predominantly based on hematocrit (HCT) values (>52% in men and >48% in women) in JAK2 mutated patients. We examined clinical features at diagnosis and outcome in 397 mutated PV patients showing a bone marrow (BM) morphology conforming with the WHO descriptions but including also cases with a HB level <18.5 g/dL in males (range 16.0–18.4) and <16.5 g/dL in females (range 15.0–16.4). These patients were regarded as masked PV (mPV) comprising 140 (35%) cases of our cohort. A comparison with the BCSH criteria based on HCT levels revealed a decrease of mPV patients to 59 (15%). In both classification systems, mPV patients were more males, presented more frequently with higher platelet counts, and increased BM reticulin fibrosis. A worsening of overall survival was documented in mPV patients in comparison with overt PV following the WHO (P = 0.011) as well as the BCSH (P = 0.0019) criteria. Risk factors for inferior survival in mPV were age >65 years and white blood cell count >15 × 109/L. Without these risk factors mPV patients had the same survival as overt PV suggesting that a fraction of patients with HB lower than that required for WHO diagnosis should still be considered as overt PV. This study has established the existence of mPV by two different classification systems based on either HB or HCT threshold values. Am. J. Hematol. 89:199–202, 2014. © 2013 Wiley Periodicals, Inc.

We examined the baseline features and clinical outcomes of 140 patients presenting with JAK2V617F positivity and a bone marrow morphology conforming with WHO criteria of polycythemia vera (PV), but a hemoglobin level of <18.5 g/dL in males (range 16.0–18.4) and <16.5 g/dL in females (range 15.0–16.4). This cohort operationally referred to as masked PV (mPV) was compared with 257 patients with overt PV and displayed male predominance, a more frequent history of arterial thrombosis and thrombocytosis. Incidence of thrombosis was similar between the two groups but mPV displayed significantly higher rates of progression to myelofibrosis and acute leukemia and inferior survival. In multivariable analysis mPV diagnosis was an independent predictor of poor survival along with age >65 years and leukocyte count >10 × 109/L. Our data suggest that mPV is a heterogeneous myeloproliferative neoplasia and not necessarily an early/ pre‐polycythemic form of classical PV that at onset in a small fraction of patients clinically may mimic essential thrombocythemia. On the other hand, the majority mPV may have a longer prodrome of undiagnosed PV or a disease biology akin to primary myelofibrosis‐post PV myelofibrosis that could explain the worsening of outcome in comparison to overt/classical manifestations. Am. J. Hematol. 89:52–54, 2014. © 2013 Wiley Periodicals, Inc.

Disease overviewChronic myelomonocytic leukemia (CMML) is a clonal hematopoietic stem cell disorder that is classified as a myelodysplastic/myeloproliferative neoplasm by the 2008 World Health Organization classification of hematopoietic tumors. It is characterized by absolute monocytosis (>1 × 109/L) in the peripheral blood that persists for at least 3 months.DiagnosisThe diagnosis of CMML rests on a combination of morphologic, histopathologic and chromosomal abnormalities in the bone marrow. It is important to exclude other myeloproliferative neoplasms and infectious/autoimmune conditions that can cause monocytosis.Risk stratificationSeveral CMML‐specific prognostic models incorporating novel mutations have been recently reported. The Mayo prognostic model classified CMML patients into three risk groups based on: increased absolute monocyte count, presence of circulating blasts, hemoglobin <10 gm/dL and platelets <100 × 109/L. The median survival was 32 months, 18.5 months and 10 months in the low, intermediate, and high‐risk groups, respectively. The Groupe Francophone des (GFM) score segregated CMML patients into three risk groups based on: age >65 years, WBC >15 × 109/L, anemia, platelets <100 × 109/L, and ASXL1 mutation status. After a median follow‐up of 2.5 years, survival ranged from not reached in the low‐risk group to 14.4 months in the high‐risk group.Risk‐adapted therapyThe Food and Drug Administration has approved azacitidine and decitabine for the treatment of patients with CMML. An allogeneic stem cell transplant can potentially offer a curative option to a subset of CMML patients. It is hoped that with the discovery of several novel mutations, targeted therapies will become available in the near future. Am. J. Heamtol. 88:968–974, 2013. © 2013 Wiley Periodicals, Inc.

Key Points Treatment response criteria for MF must capture drug benefit in terms of symptom burden. The current document includes stricter definitions of red cell transfusion need and independence.

We used high resolution mate‐pair sequencing (HRMPS) in 15 patients with primary myelofibrosis (PMF): eight with normal karyotype and seven with PMF‐characteristic cytogenetic abnormalities, including der(6)t(1;6)(q21–23;p21.3) (n = 4), der(7)t(1;7)(q10;p10) (n = 2), del(20)(q11.2q13.3) (n = 3), and complex karyotype (n = 1). We describe seven novel deletions/translocations in five patients (including two with normal karyotype) whose breakpoints were PCR‐validated and involved MACROD2, CACNA2D4, TET2, SGMS2, LRBA, SH3D19, INTS3, FOP (CHTOP), SCLT1, and PHF17. Deletions with breakpoints involving MACROD2 (lysine deacetylase; 20p12.1) were recurrent and found in two of the 15 study patients. A novel fusion transcript was found in one of the study patients (INTS3‐CHTOP), and also in an additional non‐study patient with PMF. In two patients with der(6)t(1;6)(q21–23;p21.3), we were able to map the precise translocation breakpoints, which involved KCNN3 and GUSBP2 in one case and HYDIN2 in another. This study demonstrates the utility of HRMPS in uncovering submicroscopic deletions/translocations/fusions, and precise mapping of breakpoints in those with overt cytogenetic abnormalities. The overall results confirm the genetic heterogeneity of PMF, given the low frequency of recurrent specific abnormalities, identified by this screening strategy. Currently, we are pursuing the pathogenetic relevance of some of the aforementioned findings. Am. J. Hematol. 88:741–746, 2013. © 2013 Wiley Periodicals, Inc.

SummaryMyelofibrosis (MF) is a Philadelphia chromosome–negative stem cell myeloproliferative neoplasm (MPN) associated with cytopenias, splenomegaly, constitutional symptoms, and poor prognosis. MF patients commonly express JAK2 V617F mutation and activation of Janus kinase (JAK)/signal transducer and activator of transcription (STAT) signalling. Agents targeting the JAK/STAT pathway have demonstrated efficacy in patients with MF. This study evaluated panobinostat, a pan‐deacetylase inhibitor that depletes JAK2 V617F levels and JAK/STAT signalling in MPN cells, in patients with primary MF, post–essential thrombocythaemia MF, and post–polycythaemia vera MF. Patients received panobinostat 40 mg administered three times per week. Dose reductions were permitted for toxicities. The primary endpoint was response rate at 6 months using International Working Group for Myelofibrosis Research and Treatment (IWG‐MRT) consensus criteria. Analyses of peripheral blood cells from treated patients revealed that panobinostat inhibited JAK/STAT signalling, decreased inflammatory cytokine levels, and decreased JAK2 V617F allelic burden. However, panobinostat was poorly tolerated at the dose and schedule evaluated, and only 16 of 35 patients completed ≥2 cycles of treatment. One patient (3%) achieved an IWG‐MRT response. Common adverse events were thrombocytopenia (71·4%) and diarrhoea (80·0%). Although molecular correlative analyses suggested that panobinostat inhibits key intracellular targets, limited clinical activity was observed because of poor tolerance.

Disease OverviewPolycythemia Vera (PV) and essential thrombocythemia (ET) are myeloproliferative neoplasms (MPN) primarily characterized by erythrocytosis and thrombocytosis, respectively. Other disease features include leukocytosis, splenomegaly, thrombohemorrhagic complications, vasomotor disturbances, pruritus and a small risk of disease progression into acute myeloid leukemia or myelofibrosis.DiagnosisAlmost all patients with PV harbor aJAK2mutation. When PV is suspected, the presence of aJAK2mutation highly suggests the diagnosis and its absence, combined with normal or increased serum erythropoietin level, excludes the diagnosis. Differential diagnosis of ET should include reactive thrombocytosis, chronic myeloid leukemia, prefibrotic myelofibrosis and RARS‐T (refractory anemia with ring sideroblasts associated with marked thrombocytosis). AJAK2mutation is found in 50–70% of patients with ET, myelofibrosis or RARS‐T and is capable of distinguishing reactive from clonal thrombocytosis.Risk StratificationCurrent risk stratification in PV and ET is designed to estimate the likelihood of thrombotic complications: high‐risk is defined by the presence of age >60 years or presence of thrombosis history; low‐risk is defined by the absence of both of these two risk factors. Recent data considersJAK2V617F and cardiovascular (CV) risk factors as additional risk factors for thrombosis. Presence of extreme thrombocytosis (platelet count >1,000 × 109/L) might be associated with acquired von Willebrand syndrome (AvWS) and, therefore, risk of bleeding. Risk factors for shortened survival in both PV and ET include advanced age, leukocytosis, and history of thrombosis.Risk‐Adapted TherapySurvival is near‐normal in ET and reasonably long in PV. The 10‐year risk of leukemic/fibrotic transformation is <1%/1% in ET and <3%/10% in PV. In contrast, the risk of thrombosis exceeds 20%. The main goal of therapy is therefore to prevent thrombohemorrhagic complications. In low risk patients, this is effectively and safely accomplished by the use of low‐dose aspirin in both PV and ET and phlebotomy (hematocrit target of <45%) in PV. In high risk patients, treatment with hydroxyurea is additionally recommended, although not mandated in older patients withoutJAK2V617F or CV risk factors. Treatment with busulfan or interferon‐α is usually effective in hydroxyurea failures. Screening for clinically significant AvWS is recommended before administrating aspirin in the presence of extreme thrombocytosis. Am. J. Hematol. 88:508–516, 2013. © 2013 Wiley Periodicals, Inc.

Cytogenetic classification by the revised international prognostic scoring system (IPSS‐R) and the prognostic value of monosomal karyotype (MK) were assessed in 783 patients with primary myelodysplastic syndromes (MDS). At 22 months median follow‐up, 562 (72%) deaths were recorded. Percentages of patients with IPSS‐R “very good,” “good,” “intermediate,” “poor,” and “very poor” cytogenetic categories was 5, 63, 18, 4, and 10%, respectively. The corresponding median survivals were 21, 40, 24, 18, and 6.5 months and the inter‐group differences (good vs. very good/intermediate/poor vs. very poor; P < 0.01) or similarities (very good vs. intermediate vs. poor; P = 0.79) were not significantly modified in multivariable analysis. Results were similar when analysis was restricted to 602 patients managed by supportive care. MK adversely affected survival in both poor and very poor karyotype groups (P < 0.01). In conclusion, we were unable to confirm the prognostic superiority of IPSS‐R‐very good karyotype or prognostically distinguish between very good, intermediate and poor karyotypes. Furthermore, we show additional prognostic information from MK in poor/very poor karyotype. Am. J. Hematol. 88:690–693, 2013. © 2013 Wiley Periodicals, Inc.

Key Points Evidence exists that ELN criteria for response in ET and PV issued in 2009 do not provide relevant measures of benefit for patients. Revised recommendations for assessing response are provided.