Tefferi, Ayalew

AbstractMonocytosis (absolute monocyte count, AMC ≥ 1 × 109/L) might accompany a spectrum of myeloid neoplasms, other than chronic myelomonocytic leukemia (CMML). In the current study, we examined the prevalence, laboratory and molecular correlates, and prognostic relevance of monocytosis in polycythemia vera (PV). Among 267 consecutive patients with World Health Organization (WHO)‐defined PV, 55 (21%) patients displayed an AMC of ≥1 × 109/L and 18 (7%) an AMC of ≥1.5 × 109/L. In general, PV patients with monocytosis were significantly older and displayed higher frequencies of leukocytosis (81% vs. 50% at AMC ≥1 × 109/L) and TET2/SRSF2 mutations (57%/29% vs. 19%/1% at AMC ≥ 1.5 × 109/L). In univariate analysis, AMC ≥1.5 × 109/L adversely affected overall (OS; P = .004; HR 2.6, 95% CI 1.4‐4.8) and myelofibrosis‐free (MFFS; P = .02; HR 4.4, 95% CI 1.3‐15.1) survival; during multivariable analysis, significance was borderline sustained for OS (P = .05) and MFFS (P = .06). Other independent risk factors for OS included unfavorable karyotype (P = .02, HR 3.39, 95% CI 1.17‐9.79), older age (P < .0001, HR 3.34 95% CI 1.97‐5.65), and leukocytosis ≥15 × 109/L (P = .004, HR 2.04, 95% CI 1.26‐3.29). In conclusion, in the current study, we encountered a higher than expected prevalence of monocytosis in patients with PV and the mutation profile and age distribution of PV patients with monocytosis is akin to those of patients with CMML and might partly contribute to their worse prognosis.

AbstractAtypical chronic myeloid leukemia (aCML) is an aggressive myeloid neoplasm with overlapping features of myelodysplastic syndromes (prominent granulocytic dysplasia) and myeloproliferative neoplasms (neutrophilic leukocytosis). We studied 25 molecularly‐annotated and World Health Organization defined aCML patients; median age 70 years, 84% males. Cytogenetic abnormalities were seen in 36% and gene mutations in 100%. Mutational frequencies were, ASXL1 28%, TET2 16%, NRAS 16%, SETBP1 12%, RUNX1 12%, ETNK1 8%, and PTPN11 4%. Fifteen patients (60%) had >1 mutation, while 9 (36%) had ≥3. The median overall survival (OS) was 10.8 months and at last follow up (median 11 months), 17 (68%) deaths and 2 (8%) leukemic transformations were documented. On univariate analysis, survival was adversely impacted by advanced age (P = .02), low hemoglobin (P = .01), red blood cell transfusion dependence (P = .03), high white blood cell count (P = .02), TET2 (P = .03), NRAS (P = .04), PTPN11 (P = .02) mutations and the presence of ≥3 gene mutations (P = .006); ASXL1, SETBP1, and ETNK1 mutations did not impact OS. In multivariable analysis, advanced age (P = .003) [age >67: HR 10.1, 95% CI 1.3‐119], low hemoglobin (P = .008) [HB< 10 gm/dL: HR 8.2, 95% CI 1.6‐23.2] and TET2 mutations (P = .01) [HR 8.8, 95% CI 1.6‐47.7] retained prognostic significance. We then used age >67 years, hemoglobin <10 gm/dL and the presence of TET2 mutations (each counted as one risk factor) to create a hazard ratio weighted prognostic model; effectively stratifying patients into two risk categories, low (0‐1 risk factor) and high (≥2 risk factors), with median OS of 18 and 7 months, respectively.

AbstractThe 2016 World Health Organization (WHO) diagnostic criteria for myeloproliferative neoplasms (MPN) underscore the prognostically‐relevant distinction between essential thrombocythemia (ET) and prefibrotic primary myelofibrosis (pre‐PMF). In addition, leukocytosis has been identified as an important prognostic marker in otherwise WHO‐defined ET. However, controversy remains regarding the objectivity of morphologic criteria in distinguishing ET from pre‐PMF and the precise prognostic cutoff values for leukocytosis. Serum lactate dehydrogenase (LDH) level might be a biologically more accurate measure of leukocyte turnover and a more sensitive marker of pre‐PMF, in otherwise WHO‐defined ET. In the current study of 183 consecutive patients with WHO‐defined ET, the presence of grade 1 bone marrow (BM) fibrosis did not affect presenting clinical or laboratory features; in contrast, increased serum LDH at diagnosis was associated with leukocytosis (p = .002), thrombocytosis (p < .001), palpable splenomegaly (p = .03) and higher international prognostic score (IPSET) (p = .002); serum LDH did not correlate with BM fibrosis, JAK2/CALR/MPL or TET2/ASXL1 mutations. In univariate analysis, risk factors for survival included age ≥60 years (p = .002; HR 10.2, 95% CI 2.3‐44.6), male sex (p = .02; HR 3.2, 95% CI 1.2‐8.2), leukocyte count ≥15 × 109/L (p = .007; HR 4.7, 95% CI 1.5‐14.6), and increased serum LDH (p = .002; HR 3.7, 95% CI 1.5‐9.1), but not BM fibrosis (p = .17). In multivariable analysis, age, sex and serum LDH remained significant; serum LDH also remained significant, in the context of IPSET (p = .003) and in patients with leukocytosis (p = .003). We conclude that serum LDH level carries an independent prognostic value for survival in ET and might represent a biologically more accurate surrogate for leukocytosis.

AbstractDisease OverviewRing sideroblasts (RS) are erythroid precursors with abnormal perinuclear mitochondrial iron accumulation. Two myeloid neoplasms defined by the presence of RS, include refractory anemia with ring sideroblasts (RARS), now classified under myelodysplastic syndromes with RS (MDS‐RS) and RARS with thrombocytosis (RARS‐T); now called myelodysplastic/myeloproliferative neoplasm with RS and thrombocytosis (MDS/MPN‐RS‐T).DiagnosisMDS‐RS is a lower risk MDS, with single or multilineage dysplasia (SLD/MLD), <5% bone marrow (BM) blasts and ≥15% BM RS (≥5% in the presence of SF3B1 mutations). MDS/MPN‐RS‐T, now a formal entity in the MDS/MPN overlap syndromes, has diagnostic features of MDS‐RS‐SLD, along with a platelet count ≥ 450 × 10(9)/L and large atypical megakaryocytes (similar to BCR‐ABL1 negative MPN).Mutations and KaryotypeMutations in SF3B1 are seen in ≥80% of patients with MDS‐RS‐SLD and MDS/MPN‐RS‐T, and strongly correlate with the presence of BM RS; MDS/MPN‐RS‐T patients also demonstrate JAK2V617F, ASXL1, DNMT3A, SETBP1, and TET2 mutations; with ASXL1/SETBP1 mutations adversely impacting survival. Cytogenetic abnormalities are uncommon in both diseases.Risk stratificationMost patients with MDS‐RS‐SLD are stratified into lower risk groups by the revised‐International Prognostic Scoring System (R‐IPSS). Disease outcome in MDS/MPN‐RS‐T is better than that of MDS‐RS‐SLD, but worse than that of essential thrombocythemia. Both diseases have a low risk of leukemicTreatmentAnemia and iron overload are complications seen in both and are managed similar to lower risk MDS and MPN. Aspirin therapy is reasonable in MDS/MPN‐RS‐T, especially in the presence of JAK2V617F, but the value of platelet‐lowering drugs is uncertain.

AbstractDisease overviewPolycythemia Vera (PV) and essential thrombocythemia (ET) are myeloproliferative neoplasms respectively characterized by erythrocytosis and thrombocytosis; other disease features include leukocytosis, splenomegaly, thrombosis, bleeding, microcirculatory symptoms, pruritus, and risk of leukemic or fibrotic transformation.DiagnosisPV is defined by aJAK2mutation, whose absence, combined with normal or increased serum erythropoietin level, makes the diagnosis unlikely.JAK2,CALR, andMPLmutations are the mutually exclusive “driver” mutations in ET with respective incidences of 55%, 25%, and 3%; approximately 17% are triple‐negative. However, the same molecular markers might also be present in prefibrotic myelofibrosis, whose morphological distinction from ET is prognostically relevant.Survival and leukemic/fibrotic transformationMedian survivals are approximately 14 years for PV and 20 years for ET; the corresponding values for younger patients (age <60 years) are 24 and 33 years. Life‐expectancy in ET is inferior to the control population. Driver mutational status has not been shown to affect survival in ET whereas the presence ofJAK2/MPLmutations has been associated with higher risk of arterial thrombosis and that ofMPLwith higher risk of fibrotic progression. Risk factors for overall survival in both ET and PV include advanced age, leukocytosis and thrombosis. Leukemic transformation rates at 20 years are estimated at <10% for PV and 5% for ET; fibrotic transformation rates are slightly higher. Most recently,ASXL1,SRSF2, andIDH2mutations have been associated with inferior overall, leukemia‐free or fibrosis‐free survival in PV; similarly adverse mutations in ET includedSH2B3,SF3B1,U2AF1,TP53,IDH2, andEZH2.Thrombosis risk stratificationCurrent risk stratification in PV and ET is designed to estimate the likelihood of recurrent thrombosis. Accordingly, PV includes two risk categories: high‐risk (age >60 years or thrombosis history) and low‐risk (absence of both risk factors). In ET, risk stratification includes four categories: very low risk (age ≤60 years, no thrombosis history,JAK2/MPLun‐mutated), low risk (age ≤60 years, no thrombosis history,JAK2/MPLmutated), intermediate risk (age >60 years, no thrombosis history,JAK2/MPLun‐mutated), and high risk (thrombosis historyorage >60 years withJAK2/MPLmutation). In addition, presence of extreme thrombocytosis (platelets >1000 × 10(9)/L) might be associated with acquired von Willebrand syndrome (AvWS) and, therefore, risk of bleeding.Risk‐adapted therapyThe main goal of therapy in PV and ET is to prevent thrombohemorrhagic complications. All patients with PV require phlebotomy to keep hematocrit below 45% and once‐daily aspirin (81 mg). In addition, high‐risk patients with PV require cytoreductive therapy. Very low risk ET patients might not require any form of therapy while low‐risk patients require at least once‐daily aspirin therapy. Cytoreductive therapy is also recommended for high‐risk ET patients but it is not mandatory for intermediate‐risk patients. First‐line drug of choice for cytoreductive therapy, in both ET and PV, is hydroxyurea and second‐line drugs of choice are interferon‐α and busulfan. We currently do not recommend treatment with ruxolutinib or otherJAK2inhibitors in PV or ET, unless in the presence of severe and protracted pruritus or marked splenomegaly that is not responding to the aforementioned drugs. Screening for AvWS is recommended before administrating aspirin, in the presence of extreme thrombocytosis. Am. J. Hematol. 92:95–108, 2017. © 2016 Wiley Periodicals, Inc.

Key Points More than half of patients with PV or ET harbor DNA mutations/variants other than JAK2/CALR/MPL. The presence of some of these mutations adversely affects overall, leukemia-free, or myelofibrosis-free survival.

Key Points More than 80% of patients with PMF harbor DNA variants/mutations other than JAK2/CALR/MPL. Some of these variants/mutations adversely affect overall or leukemia-free survival independent of conventional risk stratification.