Essential thrombocythemia, polycythemia vera, and myelofibrosis: current management and the prospect of targeted therapy

Somatic Variants Acquired Later in Life Associated with Thoracic Aortic Aneurysms: JAK2 V617F

The JAK2 V617F somatic variant is a well-known driver of myeloproliferative neoplasms (MPN) associated with an increased risk for athero-thrombotic cardiovascular disease. Recent studies have demonstrated its role in the development of thoracic aortic aneurysm (TAA). However, limited clinical information and level of JAK2 V617F burden have been provided for a comprehensive evaluation of potential confounders. A retrospective genotype-first study was conducted to identify carriers of the JAK2 V617F variant from an internal exome sequencing database in Yale DNA Diagnostics Lab. Additionally, the overall incidence of somatic variants in the JAK2 gene across various tissue types in the healthy population was carried out based on reanalysis of SomaMutDB and data from the UK Biobank (UKBB) cohort to compare our dataset to the population prevalence of the variant. In our database of 12,439 exomes, 594 (4.8%) were found to have a thoracic aortic aneurysm (TAA), and 12 (0.049%) were found to have a JAK2 V617F variant. Among the 12 JAK2 V617F variant carriers, five had a TAA (42%), among whom four had an ascending TAA and one had a descending TAA, with a variant allele fraction ranging from 11.2% to 20%. Among these five patients, 60% were female, and average age at diagnosis was 70 (49-79). The mean ascending aneurysm size was 5.05 cm (range 4.6-5.5 cm), and four patients had undergone surgical aortic replacement or repair. UKBB data revealed a positive correlation between the JAK2 V617F somatic variant and aortic valve disease (effect size 0.0086, p = 0.85) and TAA (effect size = 0.004, p = 0.92), although not statistically significant. An unexpectedly high prevalence of TAA in our dataset (5/594, 0.84%) is greater than the prevalence reported before for the general population, supporting its association with TAA. JAK2 V617F may contribute a meaningful proportion of otherwise unexplained aneurysm patients. Additionally, it may imply a potential JAK2-specific disease mechanism in the developmental of TAA, which suggests a possible target of therapy that warrants further investigation.

Cost-effectiveness of ropeginterferon alfa-2b-njft for the treatment of polycythemia vera

Aim: Patients with polycythemia vera (PV), a rare and chronic blood cancer, are at a higher risk for thromboembolic events, progression to myelofibrosis, and leukemic transformation. In 2021, ropeginterferon alfa-2b-njft (BESREMi®) was approved in the US to treat adults with PV. The purpose of this study is to estimate the cost-effectiveness of ropeginterferon alfa-2b-njft, used as a first- or second-line treatment, for the treatment of patients with PV in the US. Materials & methods: A Markov cohort model was developed from the healthcare system perspective in the United States. Model inputs were informed by the PROUD-PV and CONTINUATION-PV studies and published literature. The model population included both low-risk and high-risk patients with PV. The model compared ropeginterferon alfa-2b-njft used either as first- or second-line versus an alternative treatment pathway of first-line hydroxyurea followed by ruxolitinib. Results: Over the modeled lifetime, ropeginterferon alfa-2b-njft provided an additional 0.4 higher quality-adjusted life years (QALYs) and 0.4 life-years with an added cost of USD60,175, resulting in a cost per QALY of USD141,783. The model was sensitive to treatment costs, the percentage of patients who discontinue hydroxyurea, the percentage of ropeginterferon alfa-2b-njft users who switch to monthly dosing, the percentage of ropeginterferon alfa-2b-njft users as 2nd line treatment, and the treatment response rates. A younger patient age at baseline and a higher percentage of patients with low-risk disease improved the cost-effectiveness of ropeginterferon alfa-2b-njft. Conclusion: Ropeginterferon alfa-2b-njft is a cost-effective treatment option for a broad range of patients with PV, including both low- and high-risk patients and patients with and without prior cytoreductive treatment with hydroxyurea.

Characterization of myeloproliferative neoplasms in the paediatric and young adult population

The aim of this study was to compare the genomic features and clinical outcomes between paediatric and young adult patients (PAYA, <40 years) and older adults (OA, ≥40 years) with myeloproliferative neoplasms (MPN) to gain insight into pathogenesis, disease prognosis and management. Of 630 MPN patients, 171 (27%) were PAYA with an average age at diagnosis of 31 years. Females were more prevalent in PAYA than OA (71% vs 58%; p = 0.002), and PAYA more frequently presented with essential thrombocytosis (ET) at diagnosis (67% vs 39%; p < 0.001). The presence of a JAK2 somatic mutation was higher in OA (80.4% vs 64.3%; p < 0.001), while a CALR mutation or lack of any traditional driver mutation was more common in PAYA (20.5% vs 10.5%; p = 0.001, 8.8% vs 3.7%; p = 0.01 respectively). Venous thrombosis was more common in PAYA compared to OA (19.8% vs 10.7%; p = 0.002). PAYA had a higher prevalence of familial MPN and familial cancer predisposition, and two PAYA patients harboured pathogenic germline JAK2 lesions. PAYA demonstrated longer survival from diagnosis than OA (median not reached vs 13 years), while disease transformation was less frequent (19.3% vs 37.9%).

Unexpected Neurological Symptoms of Ruxolitinib: A Case Report

Ruxolitinib is a highly potent JAK2 inhibitor approved for the treatment of myelofibrosis (idiopathic or post-polycythemia vera or post-essential thrombocythemia) and, more recently, for polycythemia vera with an inadequate response to or intolerant of hydroxyurea. The most common adverse events of ruxolitinib include immunosuppression with an increased risk of reactivation of silent infections and increased non-melanoma skin cancer. The known neurological side effects of ruxolitinib are dizziness and headache, but no neurological paroxysmal episodes have been recorded. This report deals with an 80-year-old outpatient woman with polycythemia vera turned into myelofibrosis who experienced neurological episodes of hypoesthesia and weakness of right arm and leg during ruxolitinib treatment.

Prevalence of Paroxysmal Nocturnal Hemoglobinuria Clones in Myeloproliferative Neoplasm Patients: A Cross-Sectional Study

INTRODUCTION

The myeloproliferative neoplasms (MPN) are clonal diseases that confer an increased risk of thrombohemorrhagic complications. Paroxysmal nocturnal hemoglobinuria (PNH) is a rare clonal disease associated with an increased thrombotic risk. Small PNH clones are prevalent in aplastic anemia and myelodysplastic syndrome patients, but their prevalence in MPN patients is unknown.

PATIENTS AND METHODS

Consecutive patients with MPN followed up at a single center were recruited. PNH clones were analyzed in erythrocytes and white blood cells by flow cytometry.

RESULTS

PNH clones were detected in 2% of patients and were more common in JAK2 V617F positive patients. We could not detect any differences in clinical manifestations or complications in patients either with or without PNH clones because of the small patient numbers.

CONCLUSION

The prevalence of PNH clones in MPN is similar to that described in myelodysplastic syndromes. Whether PNH clones influence MPN phenotype and complications should be studied prospectively in larger patient cohorts and over long-term follow-up.

Symptom Burden and Blood Counts in Patients With Polycythemia Vera in the United States: An Analysis From the REVEAL Study

BACKGROUND

Approximately 50% of patients with polycythemia vera (PV) have PV-related symptoms at diagnosis; these symptoms might develop or worsen with time. Symptoms have been shown to negatively affect quality of life and interfere with daily activities. To our knowledge, an analysis to evaluate the relationship between blood count control and symptoms has not been published.

PATIENTS AND METHODS

The Prospective Observational Study of Patients with Polycythemia Vera in US Clinical Practices (REVEAL; NCT02252159) is a multicenter, noninterventional, nonrandomized prospective observational study of patients with PV in the United States. Patients included were required to have a complete blood count result within 30 days before completing the at-enrollment Myeloproliferative Neoplasm Self-Assessment Form Total Symptom Score (MPN-SAF TSS). Symptom severity was compared between those who had blood count control versus those who did not.

RESULTS

At the time of enrollment, 1714 patients (94.5%) were being managed with cytoreductive therapy; 468 patients (25.8%) had complete hematologic remission (CHR), 1614 patients (89.0%) had ≥1 controlled blood count, and 1122 patients (61.9%) had ≥2 controlled blood counts. Mean MPN-SAF TSSs were similar across patients in different blood count control groups. Fatigue was the most frequently reported symptom. The severity of individual symptoms, except those of pruritus and night sweats, was not affected by CHR or the number of blood counts that were controlled.

CONCLUSION

Symptom burden in patients with PV can persist despite control of blood counts, which suggests some discordance between laboratory values and symptom burden. Consequently, regular monitoring of symptom burden should be factored into the assessment of disease control.

Discovery and evaluation of ZT55, a novel highly-selective tyrosine kinase inhibitor of JAK2V617F against myeloproliferative neoplasms

BACKGROUND

The JAK2-STAT signaling pathway plays a critical role in myeloproliferative neoplasms (MPN). An activating mutation in JAK2 (V617F) is present in ~ 95% of polycythemia vera, essential thrombocythemia, and primary myelofibrosis cases. This study aims to explore the selective JAK2^V617F inhibitor, evaluate the efficacy and possible mechanism of ZT55 on MPN.

METHODS

HTRF assays were conducted to evaluate the selective inhibition of ZT55 for JAKs. Cell apoptosis, proliferation, and cycle arrest assays were performed to examine the effect of ZT55 on HEL cell line with JAK2^V617F mutation in vitro. Western analysis was used to monitor the expression and activity of proteins on JAK2/STAT pathway. A mice xenograft model was established to evaluate the antitumor efficacy of ZT55 in vivo. Peripheral blood samples from patients with the JAK2^V617F mutation were collected to estimate the effect of ZT55 on erythroid colony formation by colony-forming assay.

RESULTS

We found that ZT55 showed a selective inhibition of a 0.031 μM IC₅₀ value against JAK2. It exhibited potent effects on the cellular JAK-STAT pathway, inhibiting tyrosine phosphorylation in JAK2^V617F and downstream STAT3/5 transcription factors. ZT55 inhibited the proliferation of the JAK2^V617F-expressing HEL cell line, leading to cell cycle arrest at the G₂/M phase and induction of caspase-dependent apoptosis. Notably, ZT55 also significantly suppressed the growth of HEL xenograft tumors in vivo. Further evaluation indicated that ZT55 blocked erythroid colony formation of peripheral blood hematopoietic progenitors from patients carrying the JAK2^V617F mutation.

CONCLUSION

These results suggest that ZT55 is a highly-selective JAK2 inhibitor that can induce apoptosis of human erythroleukemia cells by inhibiting the JAK2-STAT signaling.

β-Arrestin2 mediates progression of murine primary myelofibrosis

Primary myelofibrosis is a myeloproliferative neoplasm associated with significant morbidity and mortality, for which effective therapies are lacking. β-Arrestins are multifunctional adaptor proteins involved in developmental signaling pathways. One isoform, β-arrestin2 (βarr2), has been implicated in initiation and progression of chronic myeloid leukemia, another myeloproliferative neoplasm closely related to primary myelofibrosis. Accordingly, we investigated the relationship between βarr2 and primary myelofibrosis. In a murine model of MPLW515L-mutant primary myelofibrosis, mice transplanted with donor βarr2-knockout (βarr2-/-) hematopoietic stem cells infected with MPL-mutant retrovirus did not develop myelofibrosis, whereas controls uniformly succumbed to disease. Although transplanted βarr2-/- cells homed properly to marrow, they did not repopulate long-term due to increased apoptosis and decreased self-renewal of βarr2-/- cells. In order to assess the effect of acute loss of βarr2 in established primary myelofibrosis in vivo, we utilized a tamoxifen-induced Cre-conditional βarr2-knockout mouse. Mice that received Cre (+) donor cells and developed myelofibrosis had significantly improved survival compared with controls. These data indicate that lack of antiapoptotic βarr2 mediates marrow failure of murine hematopoietic stem cells overexpressing MPLW515L. They also indicate that βarr2 is necessary for progression of primary myelofibrosis, suggesting that it may serve as a novel therapeutic target in this disease.

Real world epidemiology of myeloproliferative neoplasms: a population based study in Korea 2004-2013

Myeloproliferative neoplasms (MPNs), with an expected increment in number, impose substantial economic and social burdens. To this end, we conducted a nationwide population-based descriptive epidemiology study. We also investigated medical cost associated with MPNs. Prevalence was the highest for essential thrombocythemia (ET) (range 4.1-9.0 per 100,000), followed by polycythemia vera (PV) (range 2.8-5.4 per 100,000) and primary myelofibrosis (PMF) (range 0.5-0.9 per 100,000). ET incurred the highest cumulative total cost at US$35 million and the most frequent hospital visits, while PMF incurred the highest average cost per person at US$5000. The mean hemoglobin level was 16.9 ± 2.2 g/dL for PV males and 15.5 ± 2.7 g/dL for PV females. Further analyses on hemoglobin levels showed the true positive rate of PV from the significantly elevated hemoglobin group (defined as >18.5 g/dL for men and >16.5 g/dL for women) was 3.01% and that of MPNs was 3.1%. Here, we provide the biggest population-based report on MPN epidemiology that can readily be used as a representative Asian data.

Efficacy and safety of JAK inhibitor INC424 in patients with primary and post-polycythemia vera or post-essential thrombocythemia myelofibrosis in the Chinese population

A phase II study (A2202) was performed to evaluate the efficacy and safety of JAK inhibitor ruxolitinib in 63 Chinese MF patients. Ruxolitinib was given twice a day (bid) at a starting dose of 15 mg (n = 25) or 20 mg (n = 38) based on a baseline platelet count. About 94.7% of the patients achieved a reduction in spleen size, 27.0% of which exhibited significant reduction (≥ 35%) at week 24. Significant improvement in debilitating constitutional symptoms, as assessed by MFSAF v2.0, was observed in patients treated with ruxolitinib. Ruxolitinib treatment was generally well tolerated by Chinese patients. Although the treatment was associated with an increase in certain adverse events (AEs) that were established as identified risks (anemia and thrombocytopenia), these AEs were considered manageable in this clinical setting. Ruxolitinib provided substantial reductions in splenomegaly and improvements in symptoms, and was well-tolerated by Chinese patients with MF.

Clinical features of Japanese polycythemia vera and essential thrombocythemia patients harboring CALR, JAK2V617F, JAK2Ex12del, and MPLW515L/K mutations

The risk of complication of polycythemia vera (PV) and essential thrombocythemia (ET) by thrombosis in Japanese patients is clearly lower than in western populations, suggesting that genetic background such as race may influence the clinical features. This study aimed to clarify the relationship between genetic mutations and haplotypes and clinical features in Japanese patients with PV and ET. Clinical features were assessed prospectively among 74 PV and 303 ET patients. There were no clinical differences, including JAK2V617F allele burden, between PV patients harboring the various genetic mutations. However, CALR mutation-positive ET patients had a significantly lower WBC count, Hb value, Ht value, and neutrophil alkaline phosphatase score (NAP), and significantly more platelets, relative to JAK2V617F-positive ET patients and ET patients with no mutations. Compared to normal controls, the frequency of the JAK246/1 haplotype was significantly higher among patients with JAK2V617F, JAK2Ex12del, or MPL mutations, whereas no significant difference was found among CALR mutation-positive patients. CALR mutation-positive patients had a lower incidence of thrombosis relative to JAK2V617F-positive patients. Our findings suggest that JAK2V617F-positive ET patients and CALR mutation-positive patients have different mechanisms of occurrence and clinical features of ET, suggesting the potential need for therapy stratification in the future.

N, Kuppusamy P, Purandare AV. Discovery of a Highly Selective JAK2 Inhibitor, BMS-911543, for the Treatment of Myeloproliferative Neoplasms

JAK2 kinase inhibitors are a promising new class of agents for the treatment of myeloproliferative neoplasms and have potential for the treatment of other diseases possessing a deregulated JAK2-STAT pathway. X-ray structure and ADME guided refinement of C-4 heterocycles to address metabolic liability present in dialkylthiazole 1 led to the discovery of a clinical candidate, BMS-911543 (11), with excellent kinome selectivity, in vivo PD activity, and safety profile.

A pooled analysis of overall survival in COMFORT-I and COMFORT-II, 2 randomized phase III trials of ruxolitinib for the treatment of myelofibrosis

Ruxolitinib, a potent Janus kinase 1/2 inhibitor, resulted in rapid and durable improvements in splenomegaly and disease-related symptoms in the 2 phase III COMFORT studies. In addition, ruxolitinib was associated with prolonged survival compared with placebo (COMFORT-I) and best available therapy (COMFORT-II). We present a pooled analysis of overall survival in the COMFORT studies using an intent-to-treat analysis and an analysis correcting for crossover in the control arms. Overall, 301 patients received ruxolitinib (COMFORT-I, n=155; COMFORT-II, n=146) and 227 patients received placebo (n=154) or best available therapy (n=73). After a median three years of follow up, intent-to-treat analysis showed that patients who received ruxolitinib had prolonged survival compared with patients who received placebo or best available therapy [hazard ratio=0.65; 95% confidence interval (95%CI): 0.46-0.90; P=0.01]; the crossover-corrected hazard ratio was 0.29 (95%CI: 0.13-0.63). Both patients with intermediate-2- or high-risk disease showed prolonged survival, and patients with high-risk disease in the ruxolitinib group had survival similar to that of patients with intermediate-2-risk disease in the control group. The Kaplan-Meier estimate of overall survival at week 144 was 78% in the ruxolitinib arm, 61% in the intent-to-treat control arm, and 31% in the crossover-adjusted control arm. While larger spleen size at baseline was prognostic for shortened survival, reductions in spleen size with ruxolitinib treatment correlated with longer survival. These findings are consistent with previous reports and support that ruxolitinib offers a survival benefit for patients with myelofibrosis compared with conventional therapies. (clinicaltrials.gov identifiers: COMFORT-I, NCT00952289; COMFORT-II, NCT00934544).

Efficacy and safety of ruxolitinib in Asian patients with myelofibrosis

Myelofibrosis is characterized by progressive cytopenias, bone marrow fibrosis, splenomegaly and severe constitutional symptoms. In the phase 3 Controlled Myelofibrosis Study with Oral JAK Inhibitor Treatment (COMFORT) studies, ruxolitinib, a potent Janus kinase 1 (JAK1)/JAK2 inhibitor, provided substantial improvements in splenomegaly, symptoms, quality-of-life measures and overall survival compared with placebo or best available therapy. No assessments of the efficacy and safety of ruxolitinib have been conducted in Asian patients. Here, we describe results from an open-label, single-arm, phase 2 trial evaluating ruxolitinib in Asian patients with myelofibrosis (n = 120). The primary endpoint was met, with 31.7% of patients achieving a ≥ 35% reduction from baseline spleen volume at week 24. As measured by the 7-day Myelofibrosis Symptom Assessment Form v2.0, 49% of patients achieved a ≥ 50% reduction from baseline in total symptom score. Adverse events were consistent with those seen in the COMFORT studies. Ruxolitinib was well tolerated in Asian patients with myelofibrosis and provided substantial reductions in splenomegaly and improvements in symptoms.

Epidemiology of myelofibrosis, essential thrombocythemia, and polycythemia vera in the European Union

BACKGROUND

Primary myelofibrosis (PMF), essential thrombocythemia (ET), and polycythemia vera (PV) are BCR ABL-negative myeloproliferative neoplasms (MPN). Published epidemiology data are scarce, and multiple sources are needed to assess the disease burden.

METHODS

We assembled the most recent information available on the incidence and prevalence of myelofibrosis (MF), ET, and PV by conducting a structured and exhaustive literature review of the published peer-reviewed literature in EMBASE and by reviewing online documentation from disease registries and relevant health registries in European countries. The search was restricted to human studies written in English or French and published between January 1, 2000, and December 6, 2012.

RESULTS

Eleven articles identified from EMBASE, three online hematology or oncology registries, and two Web-based databases or reports were used to summarize epidemiological estimates for MF, PV, and ET. The incidence rate of MF ranged from 0.1 per 100,000 per year to 1 per 100,000 per year. Among the various registries, the incidence of PV ranged from 0.4 per 100,000 per year to 2.8 per 100,000 per year, while the literature estimated the range of PV incidence to be 0.68 per 100,000 to 2.6 per 100,000 per year. The estimated incidence of ET was between 0.38 per 100,000 per year and 1.7 per 100,000 per year. While a few studies reported on the MPNs' prevalences, it is difficult to compare them as various types of prevalence were calculated (point prevalence vs. period prevalence) and standardization was made according to different populations (e.g., the world population and the European population).

CONCLUSION

There is a wide variation in both prevalence and incidence estimates observed across European data sources. Carefully designed studies, with standardized definitions of MPNs and complete ascertainment of patients including both primary and secondary MFs, should be conducted so that estimates of the population aimed to receive novel treatments for these neoplasms are better understood assist public health planning and provide valuable information about the burden of illness to policy makers, funding agencies, resource planners, healthcare insurers, and pharmaceutical manufacturers.

Proteomic analysis reveals heat shock protein 70 has a key role in polycythemia Vera

JAK-STAT signaling through the JAK2^V617F mutation is central to the pathogenesis of myeloproliferative neoplasms (MPN). However, other events could precede the JAK2 mutation. The aim of this study is to analyze the phenotypic divergence between polycytemia vera (PV) and essential thrombocytemia (ET) to find novel therapeutics targets by a proteomic and functional approach to identify alternative routes to JAK2 activation. Through 2D-DIGE and mass spectrometry of granulocyte protein from 20 MPN samples, showed differential expression of HSP70 in PV and ET besides other 60 proteins. Immunohistochemistry of 46 MPN bone marrow samples confirmed HSP70 expression. The median of positive granulocytes was 80% in PV (SD 35%) vs. 23% in ET (SD 34.25%). In an ex vivo model KNK437 was used as an inhibition model assay of HSP70, showed dose-dependent inhibition of cell growth and burst formation unit erythroid (BFU-E) in PV and ET, increased apoptosis in the erythroid lineage, and decreased pJAK2 signaling, as well as a specific siRNA for HSP70. These data suggest a key role for HSP70 in proliferation and survival of the erythroid lineage in PV, and may represent a potential therapeutic target in MPN, especially in PV.

Three-year efficacy, safety, and survival findings from COMFORT-II, a phase 3 study comparing ruxolitinib with best available therapy for myelofibrosis

Ruxolitinib is a potent Janus kinase (JAK)1/JAK2 inhibitor that has demonstrated rapid reductions in splenomegaly and marked improvement in disease-related symptoms and quality of life in patients with myelofibrosis (MF). The present analysis reports the 3-year follow-up (median, 151 weeks) of the efficacy and safety of Controlled Myelofibrosis Study With Oral Janus-associated Kinase (JAK) Inhibitor Treatment-II (the COMFORT-II Trial), comparing ruxolitinib with the best available therapy (BAT) in 219 patients with intermediate-2 and high-risk MF. In the ruxolitinib arm, with continued therapy, spleen volume reductions of ≥35% by magnetic resonance imaging (equivalent to approximately 50% reduction by palpation) were sustained for at least 144 weeks, with the probability of 50% (95% confidence interval [CI], 36-63) among patients achieving such degree of response. At the time of this analysis, 45% of the patients randomized to ruxolitinib remained on treatment. Ruxolitinib continues to be well tolerated. Anemia and thrombocytopenia were the main toxicities, but they were generally manageable, improved over time, and rarely led to treatment discontinuation (1% and 3.6% of patients, respectively). No single nonhematologic adverse event led to definitive ruxolitinib discontinuation in more than 1 patient. Additionally, patients randomized to ruxolitinib showed longer overall survival than those randomized to BAT (hazard ratio, 0.48; 95% CI, 0.28-0.85; log-rank test, P = .009).

Methylation profiling of SOCS1, SOCS2, SOCS3, CISH and SHP1 in Philadelphia-negative myeloproliferative neoplasm

Janus kinase-signal transducer and activator of transcription (JAK/STAT) signalling, pivotal in Philadelphia-negative (Ph-ve) myeloproliferative neoplasm (MPN), is negatively regulated by molecules including SOCSs, CISH and SHP1. SOCS1, SOCS2 and SOCS3 methylation have been studied in MPN with discordant results. Herein, we studied the methylation status of SOCS1, SOCS2 and SOCS3, CISH and SHP1 by methylation-specific polymerase chain reaction (MSP) in cell lines and 45 diagnostic marrow samples of Ph-ve MPN. Moreover, we attempted to explain the discordance of methylation frequency by mapping the studied MSP primers to the respective genes. Methylation was detected in normal controls using SOCS2 MSP primers in the 3′translated exonic sequence, but not primers around the transcription start site in the 5′ untranslated regions (5′UTR). SOCS1, SOCS2, SOCS3 and CISH were completely unmethylated in primary MPN samples and cell lines. In contrast, methylation of SHP1 was detected in 8.9% primary marrow samples. Moreover, SHP1 was completely methylated in K562 cell line, leading to reversible SHP1 silencing. A review of methylation studies of SOCS1 and SOCS3 showed that spuriously high rates of SOCS methylation had been reported using MSP primers targeting CpG sites in the 3′translated exonic sequence, which is also methylated in normal controls. However, using MSP primers localized to the 5′UTR, methylation of SOCS1, SOCS2 and SOCS3 is infrequent across all studies. In summary, methylation of SOCS1, SOCS2, SOCS3 and CISH is infrequent in Ph-ve MPN. Appropriate MSP primers are important for accurate estimation of the methylation frequency. The role of SHP1 methylation in the pathogenesis of MPN warrants further investigation.

Resolution of bone marrow fibrosis in a patient receiving JAK1/JAK2 inhibitor treatment with ruxolitinib

Ruxolitinib, a JAK1/JAK2 inhibitor, is currently the only pharmacological agent approved for the treatment of myelofibrosis. Approval was based on findings from two phase 3 trials comparing ruxolitinib with placebo (COMFORT-I) and with best available therapy (COMFORT-II) for the treatment of primary or secondary myelofibrosis. In those pivotal trials, ruxolitinib rapidly improved splenomegaly, disease-related symptoms, and quality of life and prolonged survival compared with both placebo and conventional treatments. However, for reasons that are currently unclear, there were only modest histomorphological changes in the bone marrow, and only a subset of patients had significant reductions in JAK2 V617F clonal burden. Here we describe a patient with post-polycythemia vera myelofibrosis who received ruxolitinib at our institution (Guy's and St. Thomas' NHS Foundation Trust, London, United Kingdom) as part of the COMFORT-II study. While on treatment, the patient had dramatic improvements in splenomegaly and symptoms shortly after starting ruxolitinib. With longer treatment, the patient had marked reductions in JAK2 V617F allele burden, and fibrosis of the bone marrow resolved after approximately 3 years of ruxolitinib treatment. To our knowledge, this is the first detailed case report of resolution of fibrosis with a JAK1/JAK2 inhibitor.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT00934544.

Inhibition of related JAK/STAT pathways with molecular targeted drugs shows strong synergy with ruxolitinib in chronic myeloproliferative neoplasm

This study aimed to assess the antitumour effects, molecular mechanisms of action, and potential synergy of ruxolitinib with sorafenib, KNK437, dasatinib, and perifosine, in Philadelphia-negative chronic myeloproliferative neoplasms (MPN). Cytotoxic and cytostatic effects of the different compounds were determined in the JAK2 V617F-positive cell lines, HEL and Ba/F3 (JAK2V617F EPOR) , and in primary mononuclear and bone marrow CD34-positive cells from 19 MPN patients. Ruxolitinib [50% inhibitory concentration (IC50 )(PV)  = 15 nmol/l], as well as sorafenib (IC50 PV=8μmol/l), KNK437 (IC50 PV=100μmol/l ), and perifosine (IC50 PV=15μmol/l ), were able to inhibit proliferation in cell line models and in primary cells from MPN patients. Dasatinib, KNK437, and sorafenib showed a strong synergistic effect in combination with ruxolitinib [combination index (CI)(PV)  < 0·3]. Western blot confirmed that ruxolitinib blocked ERK, and consequently STAT5 activation, sorafenib inhibited ERK, P38 and STAT5, dasatinib blocked SRC and STAT5, and KNK437 decreased the stability of the JAK2 protein, reducing its expression. Inhibiting JAK2-related proliferative pathways has the potential to inhibit cell proliferation in MPNs. Furthermore, the combination of ruxolitinib with inhibitors that target these pathways has a strong synergistic effect, which may be due to decreased activation of the common effector, STAT5.

Assessing efficacy in myelofibrosis treatment: a focus on JAK inhibition

Myelofibrosis (MF) is characterized by splenomegaly, anemia and a debilitating symptom burden (e.g., fatigue, night sweats, pruritus, bone and muscle pain, undesired weight loss). Moreover, these symptoms impair activities of daily living and quality of life. Until recently, there have been no approved therapies for MF, and management of MF has been predominantly palliative. Dysregulated JAK-STAT signaling is associated with the pathologic MF disease state. A novel class of therapies, the JAK inhibitors, offers the potential to abrogate this pathologic signaling pathway. In clinical trials of patients with intermediate- and high-risk MF, JAK inhibitors have demonstrated efficacy in reducing splenomegaly and MF-associated symptoms. Evidence from ruxolitinib trials also suggests that JAK inhibitors may improve survival outcomes.

[Clinical significance of the quantification of JAK2V617F allele burden in classical Ph-negative myeloproliferative neoplasms]

BACKGROUND AND OBJECTIVES

Our study has investigated the presence of the mutation V617F in the JAK2 gene in patients diagnosed with chronic myeloproliferative neoplasms (MPNs). Furthermore, we determined if JAK2 (V617F) allelic burden associates with a specific clinical phenotype and if its quantification can be used as a marker to predict outcome and complications in patients with MPNs.

PATIENTS AND METHODS

A retrospective observational study was conducted from 1987 to 2011 in the Haematology Department of La Paz University Hospital. The allelic burden was measured in 114 patients diagnosed with MPNs: 39 polycythemia vera (PV) patients, 71 essential thrombocythaemia patients and 6 primary myelofibrosis patients. The quantitative real-time polymerase chain reaction (qRT-PCR) technology was used to determinate the percentage of mutated alleles in peripheral blood neutrophils. Patients were divided in 2 groups: heterozygous if the result was≤50% of the tested cells, and homozygous if it was positive in>50% of the cells.

RESULTS

Sixty-nine patients were positive for the JAK2 mutation and 45 were negative. Among those positive, the mutation was associated with arterial thrombosis. In addition, we demonstrate in the homozygous group that the V617F mutation is associated to PV, advanced age, leukocytosis, marked haematopoiesis and splenomegaly.

CONCLUSIONS

The presence of V617F mutation is associated with a higher incidence of thrombosis, leukocytosis and splenomegaly. The identification of mutation on the JAK2 gene could help in a better definition of evolution and prognostic stratification of the myeloproliferative disorders.

Thrombocythemia and polycythemia in patients younger than 20 years at diagnosis: clinical and biologic features, treatment, and long-term outcome

Sixty-four patients < 20 years of age, investigated for a suspicion of Philadelphia-negative myeloproliferative disease (MPD), were retrospectively evaluated to characterize the different forms and to examine the treatments used and long-term outcome. JAK2 mutations, endogenous erythroid colony growth, and clonality were investigated in 51 children. Mutations of thrombopoietin, the thrombopoietin receptor (MPL), and the erythropoietin receptor and mutations of other genes involved in the pathogenesis of MPD were investigated in JAK2 wild-type patients. Based on our criteria for childhood MPD, we identified 34 patients with sporadic thrombocythemia (ST), 16 with hereditary thrombocytosis (HT), 11 with sporadic polycythemia (SP), and 3 with hereditary polycythemia (HP). JAK2V617F mutations were present in 47.5% of ST and in no HT. The MPLS505A mutation was detected in 15/16 HT patients and in no ST (P < .00001). The JAK2V617F mutation occurred in 27% of SP patients diagnosed according to the Polycythemia Vera Study Group or World Health Organization 2001 criteria. Children with ST received more cytoreductive drugs than those with HT (P = .0006). After a median follow-up of 124 months, no patient had developed leukemia or myelofibrosis and 5% had thrombosis; the miscarriage rate in thrombocythemic patients was 14%. The low complication rate in our population suggests that children with MPD may be managed by tailored approaches.

JAK inhibition with ruxolitinib versus best available therapy for myelofibrosis

BACKGROUND

Treatment options for myelofibrosis are limited. We evaluated the efficacy and safety of ruxolitinib, a potent and selective Janus kinase (JAK) 1 and 2 inhibitor, as compared with the best available therapy, in patients with myelofibrosis.

METHODS

We assigned 219 patients with intermediate-2 or high-risk primary myelofibrosis, post-polycythemia vera myelofibrosis, or post-essential thrombocythemia myelofibrosis to receive oral ruxolitinib or the best available therapy. The primary end point and key secondary end point of the study were the percentage of patients with at least a 35% reduction in spleen volume at week 48 and at week 24, respectively, as assessed with the use of magnetic resonance imaging or computed tomography.

RESULTS

A total of 28% of the patients in the ruxolitinib group had at least a 35% reduction in spleen volume at week 48, as compared with 0% in the group receiving the best available therapy (P<0.001); the corresponding percentages at week 24 were 32% and 0% (P<0.001). At 48 weeks, the mean palpable spleen length had decreased by 56% with ruxolitinib but had increased by 4% with the best available therapy. The median duration of response with ruxolitinib was not reached, with 80% of patients still having a response at a median follow-up of 12 months. Patients in the ruxolitinib group had an improvement in overall quality-of-life measures and a reduction in symptoms associated with myelofibrosis. The most common hematologic abnormalities of grade 3 or higher in either group were thrombocytopenia and anemia, which were managed with a dose reduction, interruption of treatment, or transfusion. One patient in each group discontinued treatment owing to thrombocytopenia, and none discontinued owing to anemia. Nonhematologic adverse events were rare and mostly grade 1 or 2. Two cases of acute myeloid leukemia were reported with the best available therapy.

CONCLUSIONS

Continuous ruxolitinib therapy, as compared with the best available therapy, was associated with marked and durable reductions in splenomegaly and disease-related symptoms, improvements in role functioning and quality of life, and modest toxic effects. An influence on overall survival has not yet been shown. (Funded by Novartis Pharmaceuticals; ClinicalTrials.gov number, NCT00934544.).

Characterization of BMS-911543, a functionally selective small-molecule inhibitor of JAK2

We report the characterization of BMS-911543, a potent and selective small-molecule inhibitor of the Janus kinase (JAK) family member, JAK2. Functionally, BMS-911543 displayed potent anti-proliferative and pharmacodynamic (PD) effects in cell lines dependent upon JAK2 signaling, and had little activity in cell types dependent upon other pathways, such as JAK1 and JAK3. BMS-911543 also displayed anti-proliferative responses in colony growth assays using primary progenitor cells isolated from patients with JAK2(V617F)-positive myeloproliferative neoplasms (MPNs). Similar to these in vitro observations, BMS-911543 was also highly active in in vivo models of JAK2 signaling, with sustained pathway suppression being observed after a single oral dose. At low dose levels active in JAK2-dependent PD models, no effects were observed in an in vivo model of immunosuppression monitoring antigen-induced IgG and IgM production. Expression profiling of JAK2(V617F)-expressing cells treated with diverse JAK2 inhibitors revealed a shared set of transcriptional changes underlying pharmacological effects of JAK2 inhibition, including many STAT1-regulated genes and STAT1 itself. Collectively, our results highlight BMS-911543 as a functionally selective JAK2 inhibitor and support the therapeutic rationale for its further characterization in patients with MPN or in other disorders characterized by constitutively active JAK2 signaling.

Efficacy of NS-018, a potent and selective JAK2/Src inhibitor, in primary cells and mouse models of myeloproliferative neoplasms

Aberrant activation of Janus kinase 2 (JAK2) caused by somatic mutation of JAK2 (JAK2V617F) or the thrombopoietin receptor (MPLW515L) plays an essential role in the pathogenesis of myeloproliferative neoplasms (MPNs), suggesting that inhibition of aberrant JAK2 activation would have a therapeutic benefit. Our novel JAK2 inhibitor, NS-018, was highly active against JAK2 with a 50% inhibition (IC₅₀) of <1 n, and had 30–50-fold greater selectivity for JAK2 over other JAK-family kinases, such as JAK1, JAK3 and tyrosine kinase 2. In addition to JAK2, NS-018 inhibited Src-family kinases. NS-018 showed potent antiproliferative activity against cell lines expressing a constitutively activated JAK2 (the JAK2V617F or MPLW515L mutations or the TEL–JAK2 fusion gene; IC₅₀=11–120 n), but showed only minimal cytotoxicity against most other hematopoietic cell lines without a constitutively activated JAK2. Furthermore, NS-018 preferentially suppressed in vitro erythropoietin-independent endogenous colony formation from polycythemia vera patients. NS-018 also markedly reduced splenomegaly and prolonged the survival of mice inoculated with Ba/F3 cells harboring JAK2V617F. In addition, NS-018 significantly reduced leukocytosis, hepatosplenomegaly and extramedullary hematopoiesis, improved nutritional status, and prolonged survival in JAK2V617F transgenic mice. These results suggest that NS-018 will be a promising candidate for the treatment of MPNs.

Uses and abuses of JAK2 and MPL mutation tests in myeloproliferative neoplasms a paper from the 2010 William Beaumont hospital symposium on molecular pathology

JAK2V617F is sufficiently prevalent in BCR-ABL1-negative myeloproliferative neoplasms (MPNs) to be useful as a clonal marker. JAK2V617F mutation screening is indicated for the evaluation of erythrocytosis, thrombocytosis, splanchnic vein thrombosis, and otherwise unexplained BCR-ABL1-negative granulocytosis. However, the mutation does not provide additional value in the presence of unequivocal morphologic diagnosis, and its presence does not necessarily distinguish one MPN from another or provide useful prognostic information. In general, quantitative cell-based JAK2V617F mutation assays are preferred because the additional information obtained on mutant allele burden enhances diagnostic certainty and facilitates monitoring of response to treatment. JAK2 exon 12 mutation screening is indicated only in the presence of JAK2V617F-negative erythrocytosis that is associated with a subnormal serum erythropoietin level. MPL mutations are neither frequent nor specific enough to warrant their routine use for MPN diagnosis, but they may be useful in resolving specific diagnostic problems. The practice of en bloc screening for JAK2V617F, JAK2 exon 12, and MPL mutations is scientifically irrational and economically irresponsible.

[Abnormal hemoglobins with high oxygen affinity in the differential diagnosis of polycythemia]

Hemoglobin variant with high oxygen affinity is an uncommon, often misdiagnosed, etiology of erythrocytosis. We report two cases of erythrocytosis. Their hemoglobin-oxygen dissociation curve showed a P50 value (the oxygen tension at which hemoglobin is 50% saturated) below the normal range. Globin chains electrophoresis and DNA analysis evidenced hemoglobin Olympia and hemoglobin Malmö, respectively. More than 200 variants of hemoglobin with increased oxygen affinity have been described, that are in about one-third responsible of secondary erythocytosis because of tissular hypoxia. Such abnormal haemoglobin identification should be routinely included in the diagnostic work-up of unexplained erythocytosis, particularly in young people.

Update on JAK2 Inhibitors in Myeloproliferative Neoplasm

Since the discovery of mutant Janus Kinase 2 (JAK2), JAK2 V617F, in a major proportion of myeloproliferative neoplasm (MPN) patients, there has been a flurry of activity in the development of JAK2 inhibitors. Pan-JAK, predominantly JAK2 and off-target JAK2 inhibitors have been developed in the short span of the past 5 years. These compounds have since been tested to varying success in both in vitro and in vivo settings with several proceeding on to advanced clinical trials. Although it was hoped that these inhibitors would be the silver bullet in the manner than imatinib was to chronic myeloid leukemia, it is becoming apparent that this is not the case for various reasons, chief of which is that a significant reduction of the underlying pathogenic clone is not achieved. In fact, the very notion that the target of JAK2 inhibitors (be it pan-JAK or JAK2 specific) is the mutant JAK2 V617F is being challenged with findings from several clinical trials showing a poor correlation between the reduction in JAK2 V617F mutant allele burden and clinical response. In view of this, it is not surprising that several groups are now investigating combinations of JAK2 inhibitors and other agents in MPN. Although much knowledge has been added in this short span of time, it is apparent that our understanding of the role of JAK2 inhibitors in the treatment scheme of MPN is only beginning.

Pomalidomide therapy for multiple myeloma and myelofibrosis: an update

Thalidomide possesses potent anti-inflammatory, immunomodulatory, and antiangiogenic properties. Thalidomide combined with corticosteroids is therapeutically active in multiple myeloma and myelofibrosis (MF). Lenalidomide and pomalidomide are second-generation immunomodulatory drugs (IMiDs) that were created by chemical modification of thalidomide with the intent to reduce toxicity and enhance therapeutic activity. Both drugs have also been shown to be active in the treatment of myeloma and MF. Thalidomide is US Food and Drug Administration (FDA)-approved for use in acute erythema nodosum leprosum and, in combination with dexamethasone, in newly diagnosed myeloma. Lenalidomide is approved for use in low/intermediate-1 risk myelodysplastic syndromes associated with transfusion-dependent anemia and a deletion 5q cytogenetic abnormality and, in combination with dexamethasone, in relapsed myeloma. Pomalidomide is currently not FDA-approved. Herein, we summarize what is currently known about the biologic and therapeutic effects of pomalidomide.

Paraneoplastic syndromes: an approach to diagnosis and treatment

Recent medical advances have improved the understanding, diagnosis, and treatment of paraneoplastic syndromes. These disorders arise from tumor secretion of hormones, peptides, or cytokines or from immune cross-reactivity between malignant and normal tissues. Paraneoplastic syndromes may affect diverse organ systems, most notably the endocrine, neurologic, dermatologic, rheumatologic, and hematologic systems. The most commonly associated malignancies include small cell lung cancer, breast cancer, gynecologic tumors, and hematologic malignancies. In some instances, the timely diagnosis of these conditions may lead to detection of an otherwise clinically occult tumor at an early and highly treatable stage. Because paraneoplastic syndromes often cause considerable morbidity, effective treatment can improve patient quality of life, enhance the delivery of cancer therapy, and prolong survival. Treatments include addressing the underlying malignancy, immunosuppression (for neurologic, dermatologic, and rheumatologic paraneoplastic syndromes), and correction of electrolyte and hormonal derangements (for endocrine paraneoplastic syndromes). This review focuses on the diagnosis and treatment of paraneoplastic syndromes, with emphasis on those most frequently encountered clinically. Initial literature searches for this review were conducted using PubMed and the keyword paraneoplastic in conjunction with keywords such as malignancy, SIADH, and limbic encephalitis, depending on the particular topic. Date limitations typically were not used, but preference was given to recent articles when possible.

Myeloproliferative disorders and the hyperviscosity syndrome

Myeloproliferative disorders and the serum hyperviscosity syndrome can rapidly manifest with emergent presentations. Hyperviscosity occurs from pathologic elevations of either the cellular or acellular (protein) fractions of the circulating blood. Classic hyperviscosity syndrome presents with the triad of bleeding diathesis, visual disturbances, and focal neurologic signs. Emergency medicine providers should be aware of these conditions and be prepared to rapidly initiate supportive and early definitive management, including plasma exchange and apharesis. Early consultation with a hematologist is essential to managing these complex patients.

Visual screening for JAK2V617F mutation by a disposable dipstick

During the last 5 years, it was discovered that the JAK2V617F somatic mutation is present in virtually all patients with polycythemia vera and a large proportion of patients with essential thrombocythemia, primary myelofibrosis, and refractory anemia with ring sideroblasts and thrombocytosis. As a result, JAK2V617F was incorporated as a new clonal marker in the 2008 revision of the WHO diagnostic criteria. Current methods for JAK2 genotyping include direct sequencing, pyrosequencing, allele-specific PCR with electrophoresis, restriction fragment length polymorphism, real-time PCR, DNA-melting curve analysis, and denaturing HPLC. Some of these methods are labor intensive and time consuming, while the others require specialized costly equipment and reagents. We report a method for direct detection of the JAK2V617F allele by the naked eye using a dipstick test in a dry-reagent format. The method comprises a triprimer PCR combined with visual detection of the products within minutes by the dipstick test. Specialized instrumentation is not involved. The requirements for highly qualified technical personnel are minimized. Because the detection reagents exist in dry form on the dipstick, there is no need for multiple pipetting and incubation steps.

JAK2 kinase inhibitors and myeloproliferative disorders

PURPOSE OF REVIEW

The pathophysiology of Philadelphia-chromosome negative myeloproliferative disorders has significantly advanced with the discovery of JAK2V617F. The prevalence of JAK2V617F mutation has made it a much anticipated target for inhibition; this review will update and assess progress.

RECENT FINDINGS

Many agents have been studied in preclinical trials, of which few have entered clinical trials. Data from the clinical trials are limited and mostly in the form of abstracts and reviews.

SUMMARY

The prevalence of the JAK2V617F mutation in the classic Philadelphia-chromosome negative myeloproliferative disorders has made it a much anticipated target for inhibition. Present in greater than 90% of patients with polycythemia vera and approximately 50% of patients with essential thrombocythemia and primary myelofibrosis, it has been hoped that targeted inhibition of JAK2V617F would achieve similar disease control as imatinib mesylate has produced in chronic myeloid leukemia. However, JAK2V617F in the Philadelphia-chromosome negative myeloproliferative disorders, unlike bcr/abl tyrosine kinase in chronic myeloid leukemia, is not a causative but rather a secondary somatic mutation. As the JAK2 inhibitors move into phase III clinical trials, their efficacy and role in therapy is becoming clearer; however, there are still many questions needing answers.

Efficacy of the JAK2 inhibitor INCB16562 in a murine model of MPLW515L-induced thrombocytosis and myelofibrosis

The discovery of JAK2 and MPL mutations in patients with myeloproliferative neoplasms (MPNs) provided important insight into the genetic basis of these disorders and led to the development of JAK2 kinase inhibitors for MPN therapy. Although recent studies have shown that JAK2 kinase inhibitors demonstrate efficacy in a JAK2V617F murine bone marrow transplantation model, the effects of JAK2 inhibitors on MPLW515L-mediated myeloproliferation have not been investigated. In this report, we describe the in vitro and in vivo effects of INCB16562, a small-molecule JAK2 inhibitor. INCB16562 inhibited proliferation and signaling in cell lines transformed by JAK2 and MPL mutations. Compared with vehicle treatment, INCB16562 treatment improved survival, normalized white blood cell counts and platelet counts, and markedly reduced extramedullary hematopoeisis and bone marrow fibrosis. We observed inhibition of STAT3 and STAT5 phosphorylation in vivo consistent with potent inhibition of JAK-STAT signaling. These data suggest JAK2 inhibitor therapy may be of value in the treatment of JAK2V617F-negative MPNs. However, we did not observe a decrease in the size of the malignant clone in the bone marrow of treated mice at the end of therapy, which suggests that JAK2 inhibitor therapy, by itself, was not curative in this MPN model.

The contribution of cyclooxygenase-1 and -2 to persistent thromboxane biosynthesis in aspirin-treated essential thrombocythemia: implications for antiplatelet therapy

We tested whether cyclooxygenase 2 (COX-2) expression and unacetylated COX-1 in newly formed platelets might contribute to persistent thromboxane (TX) biosynthesis in aspirin-treated essential thrombocythemia (ET). Forty-one patients on chronic aspirin (100 mg/day) and 24 healthy subjects were studied. Platelet COX-2 expression was significantly increased in patients and correlated with thiazole orange–positive platelets (r = 0.71, P < .001). The rate of TXA2 biosynthesis in vivo, as reflected by urinary 11-dehydro-TXB2 (TXM) excretion, and the maximal biosynthetic capacity of platelets, as reflected by serum TXB2, were higher in patients compared with aspirin-treated healthy volunteers. Serum TXB2 was significantly reduced by the selective COX-2 inhibitor NS-398 added in vitro. Patients were randomized to adding the selective COX-2 inhibitor, etoricoxib, or continuing aspirin for 7 days. Etoricoxib significantly reduced by approximately 25% TXM excretion and serum TXB2. Fourteen of the 41 patients were studied again 21 (± 7) months after the first visit. Serum TXB2 was consistently reduced by approximately 30% by adding NS398 in vitro, while it was completely suppressed with 50μM aspirin. Accelerated platelet regeneration in most aspirin-treated ET patients may explain aspirin-persistent TXA2 biosynthesis through enhanced COX-2 activity and faster renewal of unacetylated COX-1. These findings may help in reassessing the optimal antiplatelet strategy in ET.

[Chronic myeloid neoplasms. Diagnostic criteria and current therapeutic concepts]

Myeloproliferative neoplasms (MPNs) and related chronic disorders constitute a subgroup of myeloid malignancies which are defined according to clinical, morphological and molecular features by the actual World Health Organization classification of tumors of the haematopietic system. Screening procedures for a BCR-ABL fusion gene, JAK2, thrombopoietin receptor and KIT mutations are formally included in the diagnostic approach. Myelodysplastic/MPN overlap syndromes include rare entities such as refractory anemia with ringed sideroblasts characterized by a high proportion of JAK2V617F mutated cases. The paradigm of targeted treatment of chronic myeloid leukemia with imatinib has now been extended to eosinophilia-associated myeloid neoplasms with PDGFRA, PDGFRB or FGFR1 gene mutations. Pegylated interferon-alpha has convincingly been proved to reduce the JAK2 allele burden. JAK2 inhibitor drugs are currently being tested in clinical trials. The development of pathogenesis-targeted diagnostic and therapeutic approaches to the various MPNs will continue in the future.

Bilateral ureteral obstruction due to primary myelofibrosis caused hyperuricaemia

In healthy population, uric acid comprises the major component of 10-20% of renal stones. Extreme hiperuricaemia is seen in cancer patients with tumor lysis syndrome (TLS) which is classically associated with haematological malignancies with rapid tumor growth rates such as acute lymphoid leukaemia and high grade lymphomas. Primary melofibrosis (Agnogenic myeloid metaplasia- AMM) is a chronic myeloproliferative disease characterized by splenomegaly, a leukoerythroblastic blood picture, teardrop poikilocytosis and varying degrees of marrow fibrosis. Due to the increased extramedullary haematopoiesis, hiperuricemia may occur. However, TLS in patients with AMM is, according to the available literature, described just in one patient. In this paper we present a case of a 47-year-old male patient who was admitted to the hospital with symptoms of fatigue and small amount of urine, and clinical signs of plethora and enlarged spleen. The laboratory findings showed leuko-and erythrocytosis, increased levels of urea-BUN (32 mmol/l) and creatinine (766 mmol/l) as well as uric acid (920 mmol/l). The immediate abdominal ultrasound confirmed extreme splenomegaly, but also showed bilateral hydronephrosis of grade II-III with two stones in proximal part of right ureter and one in proximal part of left ureter as well as empty bladder. Stones were not seen on plain film. Since the patient was in complete anuria, with further rapid elevation of BUN and creatinine levels, bilateral ureteral stents were applicated together with extensive hydration, urine alkalization and administration of allopurinol which resulted in the complete recovery of kidney function. The bone marrow biopsy was also performed and histopathological diagnosis was: Hypercellulary phase of AMM.

Mature survival data for 176 patients younger than 60 years with primary myelofibrosis diagnosed between 1976 and 2005: evidence for survival gains in recent years

In the past 20 years, management of primary myelofibrosis (PMF) has incorporated new treatment approaches, but survival benefits have not been confirmed in controlled studies. This retrospective study includes 176 consecutive patients younger than age 60 years in whom PMF was diagnosed during a 30-year period (1976-2005). Median age at diagnosis was 50 years (range, 18-59 years), and 98 patients (55%) were men. At the time of this report, 99 patients (56%) had died; the 77 surviving patients were followed up for a median of 8 years (range, 4-24 years). Overall median survival was 9.2 years, and 15- and 20-year survival rates were 32% and 20%, respectively. According to the Dupriez Prognostic Scoring System (PSS), median survivals were 12.7, 4.8, and 2.4 years in low- (n=117), intermediate- (n=44) and high- (n=15) risk patients (P<.001). According to the International PSS, median survivals were 13.4, 9.7, 3.3, and 2.4 years in low- (n=76), intermediate-1 (n=50), intermediate-2 (n=29), and high-risk patients (n=8; P<.001). To examine the effect of decade of diagnosis on survival, we divided study patients into 3 groups by year of diagnosis: 1976-1985 (n=36), 1986-1995 (n=45), and 1996-2005 (n=95). The corresponding median survivals were 4.8, 7.3, and "not reached" (P=.003), and the difference in survival was significant during multivariable analysis that included risk scores according to the aforementioned PSSs and age as covariates. The improvement in survival in recent years was most apparent in patients with high/intermediate-risk disease (P<.002), not in those with low-risk disease (P=.42). These observations are encouraging and suggest a salutary effect from modern therapeutic approaches in PMF.

Age and platelet count are IPSS-independent prognostic factors in young patients with primary myelofibrosis and complement IPSS in predicting very long or very short survival

OBJECTIVES

The current study was designed to identify International Prognostic Scoring System (IPSS)-independent prognostic factors in young patients with primary myelofibrosis (PMF). The study also examined the overall risk profile of long-term (>15 yr) and short-term (<5 yr) survivors.

METHODS

Study patients were selected from the Mayo Clinic database for PMF, and study eligibility included age <60 yr, minimum follow-up of 5 yr and availability of IPSS-relevant variables at time of diagnosis.

RESULTS

A total of 148 consecutive patients met the above-stipulated criteria. To date, 89 (60%) patients have died; 48 (32%) died within 5 yr of their diagnosis (short-term survivors). Median follow-up of patients who are alive was 9 yr (range 5-28) with a >15-yr survival documented in 16 patients (long-term survivors). Multivariable analysis identified unfavorable IPSS category (intermediate-2/high risk), age >50 yr and platelet count <100 x 10(9)/L as independent predictors of inferior survival (P < 0.01). Median survival in the absence of all three risk factors was approximately 18 yr and was shortened to 7 and 1.6 yr in the presence of 1 or > or = 2 risk factors, respectively (P < 0.01). Among long-term survivors, 69% were age < or = 50 yr, 100% had favorable IPSS profile and 100% displayed platelet count > or = 100 x 10(9)/L; the corresponding figures for short-term survivors were 29%, 50% and 65% (P < 0.01).

CONCLUSIONS

Age and platelet count are IPSS-independent predictors of survival in young patients with PMF, and they complement the IPSS in identifying patients with very long or very short survival.

Improved outcomes using tacrolimus/sirolimus for graft-versus-host disease prophylaxis with a reduced-intensity conditioning regimen for allogeneic hematopoietic cell transplant as treatment of myelofibrosis

Allogeneic hematopoietic cell transplantation (HCT) using reduced-intensity conditioning (RIC) regimens is a potentially curative treatment for patients (patients) with myelofibrosis (MF), as we and others have reported. Nonrelapse mortality (NRM) from graft-versus-host disease (GVHD) and other complications has limited the success of this approach. As part of an ongoing prospective research study at City of Hope, a combination of tacrolimus/sirolimus +/- methotrexate (MTX) for GVHD prophylaxis has become the standard treatment for our allogeneic HCT patients. In this report, we present results for 23 consecutive patients, including extended follow up for 9 patients previously reported who received cyclosporine (CsA)/mycophenolate moffetil (MMF)+/-MTX, and the current series of 14 patients who received tacrolimus/sirolimus+/-MTX, and evaluate the impact of the GVHD prophylaxis regimen on the outcomes. Median follow-up for alive patients was 29.0 months (9.5-97.0). The estimated 2-year overall survival (OS) for the CsA/MMF cohort was 55.6% (confidence interval 36.0, 71.3), and for the tacrolimus/sirolimus cohort it was 92.9% (63.3, 98.8) (P=.047). The probability of grade III or IV acute GVHD (aGVHD) was 60% for the CsA/MMF patients, and 10% for the tacrolimus/sirolimus group (P=.0102). No significant differences were seen for grade II to IV aGVHD in the 2 groups. We conclude that the combination of tacrolimus/sirolimus+/-MTX for GVHD prophylaxis in the setting of RIC HCT for MF appears to reduce the incidence of severe aGVHD and NRM, and leads to improved OS compared to CSA/MMF+/-MTX.