Federica Delaini

Characteristics and clinical correlates of MPL 515W>L/K mutation in essential thrombocythemia.

Among 994 patients with essential thrombocythemia (ET) who were genotyped for the MPLW515L/K mutation, 30 patients carrying the mutation were identified (3.0%), 8 of whom also displayed the JAK2V671F mutation. MPLW515L/K patients presented lower hemoglobin levels and higher platelet counts than did wild type (wt) MPL; these differences were highly significant compared with MPLwt/JAK2V617F-positive patients. Reduced hemoglobin and increased platelet levels were preferentially associated with the W515L and W515K alleles, respectively. MPL mutation was a significant risk factor for microvessel disturbances, suggesting platelet hyperreactivity associated with constitutively active MPL; arterial thromboses were increased only in comparison to MPLwt/JAK2wt patients. MPLW515L/K patients presented reduced total and erythroid bone marrow cellularity, whereas the numbers of megakaryocytes, megakaryocytic clusters, and small-sized megakaryocytes were all significantly increased. These data indicate that MPLW515L/K mutations do not define a distinct phenotype in ET, although some differences depended on the JAK2V617F mutational status of the counterpart.

Identification of patients with poorer survival in primary myelofibrosis based on the burden of JAK2V617F mutated allele.

A total of 186 patients with primary myelofibrosis (PMF) were genotyped for JAK2V617F at diagnosis aimed at analyzing the correlation of mutational status and mutated allele burden with outcome variables, including time to anemia, leukocytosis, leukopenia, thrombocytopenia, massive splenomegaly, leukemia, and with overall survival. A total of 127 JAK2V617F-mutated patients (68% of whole series) were divided in quartiles of V617F allele burden. After a median follow-up of 17.2 months, 23 patients died, 15 because of leukemia. A JAK2V617F mutated status did not impact on the rate of leukemia transformation or overall survival. Patients in the lower quartile had shorter time to anemia and leukopenia and did not progress to large splenomegaly. Furthermore, survival was significantly reduced in the lower quartile compared with upper quartiles and JAK2 wild-type patients. In multivariate analysis, factors associated with reduced survival were age, a blast count more than 1%, and a JAK2V617F burden within first quartile. Causes of death in the lower quartile were represented mainly by systemic infections. We conclude that a low JAK2V617F allele burden at diagnosis is preferentially associated with a myelodepletive rather than myeloproliferative phenotype and represents an independent factor associated with shortened survival in patients with PMF.

Leukocytosis and Risk Stratification Assessment in Essential Thrombocythemia

PURPOSE Established risk factors for thrombosis in essential thrombocythemia (ET) include age and previous vascular events. We aimed to refine this risk stratification by adding baseline leukocytosis. PATIENTS AND METHODS We enrolled 657 patients with ET followed for a median of 4.5 years who developed 72 major thrombosis. Cox proportional hazard model was performed to analyze the thrombotic risk and to discriminate ET patients with or without thrombosis, multivariable C statistic index was used. We searched for leukocytes cutoff with the best sensitivity and specificity by a receiver operating characteristic curve. RESULTS Results confirmed that age and prior events are independent risk factors for thrombosis and showed a gradient between baseline leukocytosis and thrombosis. On the contrary, no significant association was found either for JAK2(V617F) allele burden and for other laboratory parameters, including platelet number. In the model with conventional risk factors alone, C statistic ratio for total thrombosis was 0.63 and when leukocytosis was added, the change was small (C = 0.67). In contrast, in younger and asymptomatic patients (low-risk category), C statistic value indicated an high risk for thrombosis in patients with leukocytosis, similar to that calculated in conventionally defined high-risk group (C = 0.65). The best leukocyte cutoff values for predicting the events was found to be 9.4 (x 10(9)/L). CONCLUSION We suggest to include baseline leukocytosis in the risk stratification of ET patients enrolled in clinical trials.

Preliminary study to identify cancer patients at high risk of venous thrombosis following major surgery

Summary This study investigated whether the pre‐surgical plasma levels of TAT and F1 + 2 of patients undergoing major surgery for localized tumours could identify patients at higher risk of thrombosis, and how heparin prophylaxis affected in vivo coagulation after cancer surgery. We measured the pre‐and post‐operative levels of TAT, F1+2, total factor VII (FVIIt) and zymogen FVII (FVIIz) in 117 cancer patients, with and without heparin prophylaxis. The end points of this study were DVT. ihitially detected by 125I‐fibrinogen uptake test and confirmed by ascending venography. Pre‐operative [TAT] and [Fl+2] of the cancer patients were significantly higher than those of age‐matched control subjects (n=50) (P<0.005 and P<0.05, respectively): pre‐operative [FVII] was not significantly different. One of the 83 patients receiving prophylaxis, and 8/34 not receiving prophylaxis developed post‐operative DVT. Of the parameters evaluated, only the pre‐operative [TAT] > 3. 5 ng/ml identified patients at higher risk for post‐operative DVT. Heparin reduced plasma TAT levels and FVII consumption following surgery, suggesting that heparin modulates coagulation associated with cancer surgery. The results of this study also suggest that the pre‐operative [TAT] may identify patients with higher risk for post‐operative DVT.

JAK2V617F allele burden and thrombosis: A direct comparison in essential thrombocythemia and polycythemia vera

OBJECTIVE A direct comparison of the incidence and risk factors of major thrombosis in essential thrombocythemia (ET) and polycythemia vera (PV) according to their respective JAK2V617F allele burden is the object of this study. MATERIALS AND METHODS We compared the rate (%/patients/year) of major thrombosis in 867 ET patients (57% JAK2V617F) with that of 415 PV patients (all JAK2V617F) and examined risk factors. RESULTS Patients with ET wild-type, ET V617F, and PV showed a rate of thrombosis of 1.4%, 2.1%, and 2.7%/patients/year, respectively. The latter was found to progressively increase according to time of diagnosis. Actuarial probability of arterial and venous thrombosis in the first 5 years of diagnosis was roughly similar in the three groups. While in the subsequent periods, the curves of mutated ET patients diverged from wild-type, and after 10 to 15 years the ET-mutated arm approached PV. CONCLUSION These findings support the concept of a continuum between ET JAK2 mutated and PV, not only in reference to the hematological phenotype, but also in terms of vascular events.

Hydroxyurea in essential thrombocythemia: rate and clinical relevance of responses by European LeukemiaNet criteria

A definition of response by cytoreductive therapy in essential thrombocythemia was recently provided by the European LeukemiaNet (ELN). Complete, partial, or no clinicohematologic responses were defined on the bases of platelet count, disease-related symptoms, spleen size, and white blood cell count. To provide estimates and clinical correlation of responses according to these criteria, we retrospectively examined 416 essential thrombocythemia patients treated with hydroxyurea for at least 12 months. Complete response, partial response, and no response were 25%, 58%, and 17%, respectively. Age more than 60 years and JAK2V617F mutation were significant predictors of response. After a median follow-up of 3.9 years, we registered 23 deaths, 16 hematologic transformations, and 27 thrombotic events (rate, 1.66% patients/year). Age, previous thrombosis, leukocytosis (white blood cell count > 10 x 10(9)/L), but not ELN responses, were independently associated with higher risk of thrombosis. The actuarial probability of thrombosis was significantly influenced by leukocytosis (P = .017) and not by platelet count, indicating that platelet number does not seem of prime relevance in the definition of ELN response.

The lymphocyte to monocyte ratio improves the IPI‐risk definition of diffuse large B‐cell lymphoma when rituximab is added to chemotherapy

The peripheral blood lymphocyte to monocyte ratio (LMR) at diagnosis can be clinically relevant in patients with diffuse large B‐cell lymphoma (DLBCL). We reviewed the outcome of 1,057 DLBCL patients followed from 1984 to 2012 at four centers. LMR was analyzed as a clinical biomarker by receiver‐operating characteristic (ROC) analysis and Harrells C‐statistics. Patients were characterized by a median age of 61 years, International Prognostic Index (IPI) score of >2 in 39%, and were treated with a rituximab‐containing chemotherapy in 66%. LMR proved strongly predictive for survival in patients treated with rituximab‐based programs, but not in those receiving chemotherapy alone. Additionally, an LMR value of ≤2.6 (as determined by ROC analysis) was associated with a worst performance status, a higher lactate dehydrogenase (LDH) level, an advanced clinical stage, and a higher IPI score (P = 0.000). In patients treated with rituximab‐supplemented chemotherapy programs, an LMR value of <2.6 was found in most of the primary refractory patients (75%) which proved as the best cutoff to predict both response and survival (P = 0.018). Finally, multivariate analysis and Harrells C‐statistics confirmed the IPI‐independent role of LMR on survival (P = 0.0000). In conclusion, LMR is a potent predictor of clinical response and survival in DLBCL treated with rituximab‐containing chemotherapy. Am. J. Hematol. 88:1062–1067, 2013.

Hydroxyurea does not appreciably reduce JAK2 V617F allele burden in patients with polycythemia vera or essential thrombocythemia.

Conflicting results about the effects of hydroxyurea on the burden of mutant allele in patients with myeloproliferative neoplasms (MPN) harboring the JAK2V617F mutation have been produced recently. Owing to these conflicting results, the aim of our study was to analyze changes of JAK2V617F allele burden occurring during long-term follow-up in 172 patients with PV or ET and the relationships with hydroxyurea treatment. We conclude that in untreated patients with ET and PV changes in V617F allele burden occur very smoothly over years and we failed to confirm previous reports supporting the effectiveness of hydroxyurea in reducing the burden of JAK2V617F allele.

Epidemiology and clinical relevance of mutations in postpolycythemia vera and postessential thrombocythemia myelofibrosis: A study on 359 patients of the AGIMM group.

Transformation to secondary myelofibrosis (MF) occurs as part of the natural history of polycythemia vera (PPV‐MF) and essential thrombocythemia (PET‐MF). Although primary (PMF) and secondary MF are considered similar diseases and managed similarly, there are few studies specifically focused on the latter. The aim of this study was to characterize the mutation landscape, and describe the main clinical correlates and prognostic implications of mutations, in a series of 359 patients with PPV‐MF and PET‐MF. Compared with PV and ET, the JAK2V617F and CALR mutated allele burden was significantly higher in PPV‐MF and/or PET‐MF, indicating a role for accumulation of mutated alleles in the process of transformation to MF. However, neither the allele burden nor the type of driver mutation influenced overall survival (OS), while absence of any driver mutation (triple negativity) was associated with significant reduction of OS in PET‐MF, similar to PMF. Of the five interrogated subclonal mutations (ASXL1, EZH2, SRSF2, IDH1, and IDH2), that comprise a prognostically detrimental high molecular risk (HMR) category in PMF, only SRSF2 mutations were associated with reduced survival in PET‐MF, and no additional mutation profile with prognostic relevance was highlighted. Overall, these data indicate that the molecular landscape of secondary forms of MF is different from PMF, suggesting that unknown mutational events might contribute to the progression from chronic phase disease to myelofibrosis. These findings also support more extended genotyping approaches aimed at identifying novel molecular abnormalities with prognostic relevance for patients with PPV‐MF and PET‐MF. Am. J. Hematol. 91:681–686, 2016.

Prognostic Impact of Bone Marrow Fibrosis in Primary Myelofibrosis. A Study of the AGIMM Group on 490 Patients

The prognostic significance of bone marrow (BM) fibrosis grade in patients with primary myelofibrosis (PMF) is still debated. A fibrosis grade greater than 1 was shown to associate with higher risk of death, and addition of fibrosis grade to IPSS score resulted in a more accurate prediction of survival. The aim of this study was to analyze the prognostic impact of BM fibrosis in 490 patients with PMF, evaluated at diagnosis, molecularly annotated and with extensive follow‐up information. We found that fibrosis grade 2 and greater on a 0–3 scale was associated with clinical characteristics indicative of a more advanced disease, such as anemia, leukopenia, thrombocytopenia, constitutional symptoms, larger splenomegaly and a higher IPSS risk category. Patients with higher grade of fibrosis were also more likely to have additional somatic mutations in ASXL1 and EZH2, that are prognostically adverse. Median survival was significantly reduced in patients with grade 2 and 3 fibrosis as compared with grade 1; this effect was maintained when analysis was restricted to younger patients. In multivariate analysis, fibrosis grade independently predicted for survival regardless of IPSS variables and mutational status; the adverse impact of fibrosis was noticeable especially in lower IPSS risk categories. Overall, results indicate that higher grades of fibrosis correlate with unique clinical and molecular aspects and represent an independent adverse variable in patients with PMF; these observations deserve confirmation in prospectively designed series of patients. Am. J. Hematol. 91:918–922, 2016.