Tefferi, Ayalew

Most studies in polycythemia vera (PV) include patients with both remote and most recent diagnostic periods and are therefore vulnerable to inaccurate interpretation of time‐dependent data. We addressed the particular issue by analyzing presenting characteristics and outcome data among 1,545 patients with WHO‐defined PV stratified by a diagnosis period of before or after 2005, which coincides with the first description of JAK2V617F as the molecular marker of PV. Patients diagnosed after 2005 displayed lower hemoglobin values (P < 0.0001) and older age (P = 0.007) at diagnosis; we suggest ease of diagnosis offered by a molecular marker enabled earlier diagnosis and broader application across older age groups that is further enhanced by recent trends in increased attention and health monitoring for the elderly. Post‐2005 diagnosed patients were also more or less likely to receive aspirin and cytoreductive therapy, respectively, and, despite their older age distribution, displayed significantly lower risk of thrombosis in high risk disease. Regardless of the contributing factors to the latter phenomenon, our observations underscore the need to reassess current demographics and frequencies of thrombosis in clinical trial designs including thrombosis prevention in PV. Am. J. Hematol. 90:434–437, 2015. © 2015 Wiley Periodicals, Inc.

Among 274 patients with chronic myelomonocytic leukemia (CMML) and followed for a median of 17.1 months, blast transformation (BT) occurred in 36 (13%). On multivariable analysis, risk factors for BT were presence of circulating blasts (HR 5.7; 95% CI 2.8–11.9) and female gender (HR 2.6; 95% CI 1.3–5.1); the results remained unchanged when analysis was restricted to CMML‐1. ASXL1/SRSF2/SF3B1/U2AF1/SETBP1 mutational frequencies were not significantly different between time of CMML diagnosis and BT. Median survival post‐BT was 4.7 months (5‐year survival 6%) and better with allogeneic stem cell transplant (SCT) (14.3 months vs. 4.3 months for chemotherapy vs. 0.9 months for supportive care; P = 0.03). Neither karyotype nor mutational status was independently associated with risk of BT or post‐BT survival. We conclude that female patients with CMML and those with circulating blasts are at a higher risk of BT. Post‐BT survival is dismal and our observations suggest consideration of allogeneic SCT prior to BT.Am. J. Hematol. 90:411–416, 2015. © 2015 Wiley Periodicals, Inc.

Disease overview:Polycythemia 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.Diagnosis:PV is defined by aJAK2mutation, whose absence, combined with normal or increased serum erythropoietin level, makes the diagnosis unlikely. Differential diagnosis in ET includes reactive thrombocytosis, chronic myeloid leukemia, and prefibrotic myelofibrosis. Janus kinase 2 (JAK2), calreticulin (CALR), or myeloproliferative leukemia virus oncogene (MPL) mutations occur in approximately 55%, 25%, and 3% of ET patients, respectively. The same molecular markers are also present in prefibrotic myelofibrosis, which needs to be morphologically distinguished from ET.Survival and leukemic/fibrotic transformation:Median survivals are ∼14 years for PV and 20 years for ET; the corresponding values for younger patients are 24 and 33 years. Life‐expectancy in ET is inferior to the control population.JAK2/CALRmutational status does not affect survival in ET. Risk factors for survival in 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.Thrombosis risk stratification:Current risk stratification in PV and ET is designed to estimate the likelihood of recurrent thrombosis: 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 considerJAK2V617F and cardiovascular risk factors as additional risk factors. Presence of extreme thrombocytosis might be associated with acquired von Willebrand syndrome (AvWS) and, therefore, risk of bleeding.Risk‐adapted therapy:The main goal of therapy in PV and ET is to prevent thrombohemorrhagic complications. In low risk patients, this is accomplished by the use of low‐dose aspirin and phlebotomy (hematocrit target <45%) in PV. In high risk (for thrombosis) patients, treatment with hydroxyurea is additionally recommended. Treatment with busulfan or interferon‐α is usually effective in hydroxyurea failures and the additional value of JAK inhibitor therapy in such cases is limited. Screening for AvWS is recommended before administrating aspirin, in the presence of extreme thrombocytosis. Am. J. Hematol. 90:163–173, 2015. © 2014 Wiley Periodicals, Inc.

SummaryAmong 826 patients with primary myelofibrosis (PMF) and analysable metaphases on cytogenetic studies, 352 (42·6%) had abnormal karyotype, of which 240 (68·2%) were sole aberrations and 48 (13·6%) were complex; the most frequent abnormalities were 20q− (23·3%), 13q− (18·2%), +8 (11·1%), +9 (9·9%), chromosome 1q+ (9·7%) and −7/7q− (7·1%). Phenotypic correlates included: abnormal karyotype with anaemia (P = 0·02), leucopenia (P < 0·01) and thrombocytopenia (P < 0·01); complex karyotype with younger age (P = 0·04) and thrombocytopenia (P < 0·01); leucopenia with 20q−, +8 and −7/7q− and thrombocytopenia with 20q− and −7/7q−. Cytopenias were less likely to occur with 13q−. 476 patients were annotated for JAK2/CALR/MPL mutations; abnormal karyotype frequencies were 43% in JAK2, 42% CALR, 33% MPL mutated and 34% triple‐negative cases (P = 0·3). A proportion of patients were also screened for ASXL1, EZH2, IDH1, IDH2, SRSF2, U2AF1 and SF3B1 mutations; in all instances, mutational frequencies were higher in patients with normal karyotype, reaching significance for ASXL1 (P = 0·02) and U2AF1 (P = 0·01). 13q− was associated with mutant CALR (P = 0·03), +9 with mutant JAK2 (P = 0·02) and 20q− with mutant SRSF2 (P = 0·02). The current PMF study provides detailed cytogenetic information and correlations with mutations and clinical phenotype.

SummaryMomelotinib (a JAK1 and JAK2 inhibitor) induces both anaemia and spleen responses in myelofibrosis (MF). Momelotinib treatment‐emergent peripheral neuropathy (TE‐PN) was documented in 44 (44%) of 100 MF patients treated at our institution; median time of TE‐PN onset was 32 weeks and duration 11 months. Improvement after drug dose reduction or discontinuation was documented in only two patients. TE‐PN was significantly associated with treatment response (P = 0·02) and longer survival (P = 0·048) but significance was lost during multivariate analysis that included treatment duration. TE‐PN did not correlate with initial or maximum momelotinib dose or previous treatment with JAK inhibitor or thalidomide.

Four hundred and nine patients with chronic myelomonocytic leukemia (CMML) were included in the international collaborative study (268 (66%) and 141 (34%) from Mayo clinic and French consortium respectively). Thirty percent displayed an abnormal karyotype, including; 72% sole, 16% two, and 11% complex abnormalities. The most common abnormalities included; +8 (23%), ‐Y (20%), ‐7/7q‐(14%), 20q‐ (8%), +21 (8%), and der(3q) (8%). Patients with an abnormal karyotype were more likely to be elderly (P = 0.03), be anemic (P = 0.0009), have leukocytosis (P = 0.02) with neutrophilia (P = 0.03), demonstrate increased circulating immature myeloid cells (P = 0.0003), peripheral blood blasts (P < 0.0001), and bone marrow blasts (P < 0.0001). ASXL1 (P = 0.04) and SF3B1 (P = 0.03) mutations clustered with an abnormal karyotype, whereas SRSF2 (P = 0.02) mutations occurred more commonly with a normal karyotype. A step‐wise survival analysis resulted in three distinct cytogenetic risk categories: high (complex and monosomal karyotypes), intermediate (all abnormalities not in the high or low risk groups) and low [normal, sole ‐Y and sole der (3q)] with median survivals of 3 [hazard ratio (HR) = 8.1, 95% confidence interval (CI) = 4.6–14.2], 20 (HR = 1.7, 95% CI = 1.2–2.3) and 41 months, respectively. In multivariable analysis, this particular cytogenetic risk stratification remained significant in the context of the Molecular Mayo Model (P < 0.0001), MD Anderson prognostic model (P < 0.0001), the GFM CMML model (P < 0.0001) and was effective in predicting leukemic transformation (P = 0.004). Am. J. Hematol. 89:1111–1115, 2014. © 2014 Wiley Periodicals, Inc.

Abstract Janus kinase-2 (JAK2)/STAT pathway activation is commonly observed in myeloproliferative neoplasms and plays an important role in disease development and progression. The V617F activating mutation in the JAK2 pseudokinase domain is found in 95% of patients with polycythemia vera (PV) and in 50-70% of patients with primary myelofibrosis (MF) or essential thrombocythemia (ET). Studies have shown the clinical efficacy of JAK2 inhibitors in treating MF in terms of a reduction in splenomegaly and relief of constitutional symptoms. A reduction in the JAK2V617F allele burden after treatment with a JAK2-targeted agent could be a surrogate for a disease-modifying effect of this therapy. To demonstrate this, a robust method that can accurately measure the JAK2V617F allele burden is required. Here, we report the development of a sensitive quantitative PCR (qPCR) assay to determine the JAK2V617F allele burden in patients treated with SAR302503, the validation of the assay in a Phase 0 clinical study and implementation in a phase II study using samples from patients with MF. The assay demonstrated robust performance, with high sensitivity (LLOD=0.05% and LLOQ=0.5%) and accuracy. A phase 0 study in MF, PV, and ET patients showed that (1) there was minimal intra-subject sampling variability in JAK2V617F allele burden, and (2) whole-blood samples are stable for at least 48 hours at ambient conditions for DNA preparation without a significant impact on JAK2V617F allele burden measurement.Of the 31 patients with intermediate-2 or high-risk MF enrolled in a phase II clinical study (NCT01420770), baseline samples were available for 29 patients and of these, 26 were JAK2V617F-positive using this assay. Of the 19/26 patients for whom samples were available at all 3 time points, the median allele burden was 93% at baseline, 87% at the end of Cycle 3, and 78% at the end of Cycle 6. Among the 24 patients who were JAK2V617F-positive and for whom spleen measurements were available at the end of Cycle 6, a total of 15 (63%) had a spleen response (≥ 35% reduction in spleen volume by MRI versus baseline). In contrast, two JAK2V617F-negative patients did not have a spleen response. Patients with baseline allele burden levels of 0 to &lt;25%, 25% to 75%, and ≥75% showed spleen response rates of 50%, 44%, and 69%, respectively, at the end of Cycle 6. JAK2V617F allele burden will continue to be assessed every 3 cycles. Longer follow up is needed to determine the clinical effect of allele burden reduction. Citation Format: Feng Liu, Moshe Talpaz, Animesh Pardanani, Catriona Jamieson, Nashat Gabrail, Ayalew Tefferi, Tianlei Lei, Rita Greco, Francisco Adrian, Nikki Daskalakis, Claudia Lebedinsky, Pamela Cohen, Donald Bergstrom. Determination of JAK2V617F allele burden in a phase II study of patients with myelofibrosis treated with SAR302503 using a sensitive and robust allele-specific qPCR assay. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr LB-294. doi:10.1158/1538-7445.AM2013-LB-294