Citations

Purpose The WHO diagnostic criteria underscore the role of bone marrow (BM) morphology in distinguishing essential thrombocythemia (ET) from early/prefibrotic primary myelofibrosis (PMF). This study examined the clinical relevance of such a distinction. Methods Representatives from seven international centers of excellence for myeloproliferative neoplasms convened to create a clinicopathologic database of patients previously diagnosed as having ET (N = 1,104). Study eligibility criteria included availability of treatment-naive BM specimens obtained within 1 year of diagnosis. All bone marrows subsequently underwent a central re-review. Results Diagnosis was confirmed as ET in 891 patients (81%) and was revised to early/prefibrotic PMF in 180 (16%); 33 patients were not evaluable. In early/prefibrotic PMF compared with ET, the 10-year survival rates (76% and 89%, respectively) and 15-year survival rates (59% and 80%, respectively), leukemic transformation rates at 10 years (5.8% and 0.7%, respectively) and 15 years (11.7% and 2.1%, respectively), and rates of progression to overt myelofibrosis at 10 years (12.3% and 0.8%, respectively) and 15 years (16.9% and 9.3%) were significantly worse. The respective death, leukemia, and overt myelofibrosis incidence rates per 100 patient-years for early/prefibrotic PMF compared with ET were 2.7% and 1.3% (relative risk [RR], 2.1; P < .001), 0.6% and 0.1% (RR, 5.2; P = .001), and 1% and 0.5% (RR, 2.0; P = .04). Multivariable analysis confirmed these findings and also identified age older than 60 years (hazard ratio [HR], 6.7), leukocyte count greater than 11 × 10 9 /L (HR, 2.01), anemia (HR, 2.95), and thrombosis history (HR, 2.81) as additional risk factors for survival. Thrombosis and JAK2V617F incidence rates were similar between the two groups. Survival in ET was similar to the sex- and age-standardized European population. Conclusion This study validates the clinical relevance of strict adherence to WHO criteria in the diagnosis of ET and provides important information on survival, disease complication rates, and prognostic factors in strictly WHO-defined ET and early/prefibrotic PMF.

Abstract Symptomatic burden in myeloproliferative neoplasms is present in most patients and compromises quality of life. We sought to validate a broadly applicable 18-item instrument (Myeloproliferative Neoplasm Symptom Assessment Form [MPN-SAF], coadministered with the Brief Fatigue Inventory) to assess symptoms of myelofibrosis, essential thrombocythemia, and polycythemia vera among prospective cohorts in the United States, Sweden, and Italy. A total of 402 MPN-SAF surveys were administered (English [25%], Italian [46%], and Swedish [28%]) in 161 patients with essential thrombocythemia, 145 patients with polycythemia vera, and 96 patients with myelofibrosis. Responses among the 3 administered languages showed great consistency after controlling for MPN subtype. Strong correlations existed between individual items and key symptomatic elements represented on both the MPN-SAF and the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire-C30. Enrolling physicians' blinded opinion of patient symptoms (6 symptoms assessed) were highly correlated with corresponding patients' responses. Serial administration of the English MPN-SAF among 53 patients showed that most MPN-SAF items are well correlated (r > 0.5, P < .001) and highly reproducible (intraclass correlation coefficient > 0.7). The MPN-SAF is a comprehensive and reliable instrument that is available in multiple languages to evaluate symptoms associated with all types of MPNs in clinical trials globally.

Abstract In an international collaborative study, a central histologic review identified 891 patients with essential thrombocythemia, strictly defined by World Health Organization criteria. After a median follow-up of 6.2 years, 109 (12%) patients experienced arterial (n = 79) or venous (n = 37) thrombosis. In multivariable analysis, predictors of arterial thrombosis included age more than 60 years (P = .03; hazard ratio [HR] = 1.7), thrombosis history (P = .003; HR = 2.1), cardiovascular risk factors including tobacco use, hypertension, or diabetes mellitus (P = .007; HR = 1.9), leukocytosis (> 11 × 109/L; P = .04; HR = 1.7), and presence of JAK2V617F (P = .009; HR = 2.6). In contrast, only male gender predicted venous thrombosis. Platelet count more than 1000 × 109/L was associated with a lower risk of arterial thrombosis (P = .007; HR = 0.4). These associations, except the one with leukocytosis, remained significant (or near significant) when analysis was restricted to JAK2V617F-positive cases. The current study clarifies the contribution of specific disease and host characteristics to the risk of arterial versus venous thrombosis in essential thrombocythemia.

Purpose The Dynamic International Prognostic Scoring System (DIPSS) for primary myelofibrosis (PMF) uses five risk factors to predict survival: age older than 65 years, hemoglobin lower than 10 g/dL, leukocytes higher than 25 × 10 9 /L, circulating blasts ≥ 1%, and constitutional symptoms. The main objective of this study was to refine DIPSS by incorporating prognostic information from karyotype, platelet count, and transfusion status. Patients and Methods Mayo Clinic databases for PMF were used to identify patients with available bone marrow histologic and cytogenetic information. Results Seven hundred ninety-three consecutive patients were selected and divided into two groups based on whether or not their referral occurred within (n = 428; training set) or after (n = 365; test set) 1 year of diagnosis. Multivariable analysis identified DIPSS, unfavorable karyotype, platelets lower than 100 × 10 9 /L, and transfusion need as independent predictors of inferior survival. Hazard ratio (HR) –weighted adverse points were assigned to these variables to develop a composite prognostic model using the training set. The model was subsequently validated in the test set, and its application to all 793 patients resulted in median survivals of 185, 78, 35, and 16 months for low, intermediate-1 (HR, 2.2; 95% CI, 1.4 to 3.6), intermediate-2 (HR, 4.9; 95% CI, 3.2 to 7.7), and high-risk groups (HR, 10.7; 95% CI, 6.8 to 16.9), respectively (P < .001). Leukemia-free survival was predicted by the presence of thrombocytopenia or unfavorable karyotype (10-year risk of 31% v 12%; HR, 3.3; 95% CI, 1.9 to 5.6). Conclusion DIPSS plus effectively combines prognostic information from DIPSS, karyotype, platelet count, and transfusion status to predict overall survival in PMF. In addition, unfavorable karyotype or thrombocytopenia predicts inferior leukemia-free survival.

Abstract Age older than 65 years, hemoglobin level lower than 100 g/L (10 g/dL), white blood cell count greater than 25 × 109/L, peripheral blood blasts 1% or higher, and constitutional symptoms have been shown to predict poor survival in primary myelofibrosis (PMF) at diagnosis. To investigate whether the acquisition of these factors during follow-up predicts survival, we studied 525 PMF patients regularly followed. All 5 variables had a significant impact on survival when analyzed as time-dependent covariates in a multivariate Cox proportional hazard model and were included in 2 separate models, 1 for all patients (Dynamic International Prognostic Scoring System [DIPSS]) and 1 for patients younger than 65 years (age-adjusted DIPSS). Risk factors were assigned score values based on hazard ratios (HRs). Risk categories were low, intermediate-1, intermediate-2, and high in both models. Survival was estimated by the HR. When shifting to the next risk category, the HR was 4.13 for low risk, 4.61 for intermediate-1, and 2.54 for intermediate-2 according to DIPSS; 3.97 for low risk, 2.84 for intermediate-1, and 1.81 for intermediate-2 according to the age-adjusted DIPSS. The novelty of these models is the prognostic assessment of patients with PMF anytime during their clinical course, which may be useful for treatment decision-making.

Purpose Thalidomide and lenalidomide can alleviate anemia in myelofibrosis. However, their value is undermined by their respective potential to cause peripheral neuropathy and myelosuppression. We therefore evaluated the safety and therapeutic activity of another immunomodulatory drug, pomalidomide. Methods In a phase II randomized, multicenter, double-blind, adaptive design study, four treatment arms were evaluated: pomalidomide (2 mg/d) plus placebo, pomalidomide (2 mg/d) plus prednisone, pomalidomide (0.5 mg/d) plus prednisone, and prednisone plus placebo. Pomalidomide was administered for up to 12 28-day treatment cycles. Prednisone (30 mg/d) was given in a tapering dose schedule during the first three cycles. Response was assessed by International Working Group criteria. Results Eighty-four patients with myelofibrosis-associated anemia were randomly assigned to the aforementioned treatment arms: 22, 19, 22, and 21, respectively. Response in anemia was documented in 20 patients, including 15 who became transfusion independent. Response rates in the four treatment arms were 23% (95% CI, 5% to 41%), 16% (95% CI, 0% to 33%), 36% (95% CI, 16% to 56%), and 19% (95% CI, 2% to 36%). The corresponding figures for patients receiving ≥ 3 cycles of treatment (n = 62) were 38%, 23%, 40%, and 25%. Response to pomalidomide with or without prednisone was durable (range, 3.2 to 16.9+ months) and significantly better in the absence of leukocytosis (37% v 8%; P = .01); JAK2V617F or cytogenetic status did not affect response. Grade ≥ 3 toxicities were infrequent and included (in each treatment arm) neutropenia (9%; 16%; 5%; 5%), thrombocytopenia (14%; 16%; 9%; 5%), and thrombosis (9%; 5%; 0%; 0%). Conclusion Pomalidomide therapy at 0.5 or 2 mg/d with or without an abbreviated course of prednisone is well tolerated in patients with myelofibrosis and active in the treatment of anemia.

Abstract Therapeutic decision-making in primary myelofibrosis (PMF) is becoming more challenging because of the increasing use of allogeneic stem cell transplantation and new investigational drugs. To enhance this process by developing a highly discriminative prognostic system, 1054 patients consecutively diagnosed with PMF at 7 centers were studied. Overall median survival was 69 months (95% confidence interval [CI]: 61-76). Multivariate analysis of parameters obtained at disease diagnosis identified age greater than 65 years, presence of constitutional symptoms, hemoglobin level less than 10 g/dL, leukocyte count greater than 25 × 109/L, and circulating blast cells 1% or greater as predictors of shortened survival. Based on the presence of 0 (low risk), 1 (intermediate risk-1), 2 (intermediate risk-2) or greater than or equal to 3 (high risk) of these variables, 4 risk groups with no overlapping in their survival curves were delineated; respective median survivals were 135, 95, 48, and 27 months (P < .001). Compared with prior prognostic models, the new risk stratification system displayed higher predictive accuracy, replicability, and discriminating power. In 409 patients with assessable metaphases, cytogenetic abnormalities were associated with shorter survival, but their independent contribution to prognosis was restricted to patients in the intermediate-risk groups. JAK2V617F did not cluster with a specific risk group or affect survival.