Primary myelofibrosis: 2014 update on diagnosis, risk-stratification, and management

Immunophenotype of myeloid granulocytes in Chinese patients with BCR::ABL1-negative myeloproliferative neoplasms

Typical BCR::ABL1-negative myeloproliferative neoplasms (MPN) are mainly referred to as polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofbrosis (PMF). Granulocytes in MPN patients are involved in their inflammation and form an important part of the pathophysiology of MPN patients. It has been shown that the immunophenotype of granulocytes in MPN patients is altered. We used flow cytometry to explore the immunophenotype of MPN patients and correlate it with clinical parameters. The results showed that PMF patients and PV patients had higher CD15+CD11b+ granulocytes than ET patients and normal controls. When grouped by gene mutation, changes in the granulocyte immunophenotype of MPN patients were independent of the JAK2V617F and CALR mutations. There was no significant heterogeneity in immunophenotype between ET patients and Pre-PMF, and between Overt-PMF and Pre-PMF patients. Granulocytes from some MPN patients showed an abnormal CD13/CD16 phenotype with a significant increase in mature granulocytes on molecular and cytomorphological grounds, and this abnormal pattern occurred significantly more frequently in PMF patients than in ET patients. CD15-CD11b- was negatively correlated with WBC and Hb and positively correlated with DIPSS score, whereas high CD10+ granulocytes were significantly and negatively associated with prognostic system IPSS and DIPSS scores in PMF patients. In conclusion, this study demonstrates the landscape of bone marrow granulocyte immunophenotypes in MPN patients. MPN patients, especially those with PMF, have a significant granulocyte developmental overmaturation phenotype. CD10+ granulocytes may be involved in the prognosis of PMF patients.

Management of classical Philadelphia chromosome-negative myeloproliferative neoplasms in Asia: consensus of the Asian Myeloid Working Group

Myeloproliferative neoplasms (MPN) are a heterogeneous group of clonal hematopoietic stem cell disorders characterized clinically by the proliferation of one or more hematopoietic lineage(s). The classical Philadelphia-chromosome (Ph)-negative MPNs include polycythemia vera (PV), essential thrombocythemia (ET) and primary myelofibrosis (PMF). The Asian Myeloid Working Group (AMWG) comprises representatives from fifteen Asian centers experienced in the management of MPN. This consensus from the AMWG aims to review the current evidence in the risk stratification and treatment of Ph-negative MPN, to identify management gaps for future improvement, and to offer pragmatic approaches for treatment commensurate with different levels of resources, drug availabilities and reimbursement policies in its constituent regions. The management of MPN should be patient-specific and based on accurate diagnostic and prognostic tools. In patients with PV, ET and early/prefibrotic PMF, symptoms and risk stratification will guide the need for early cytoreduction. In younger patients requiring cytoreduction and in those experiencing resistance or intolerance to hydroxyurea, recombinant interferon-α preparations (pegylated interferon-α 2A or ropeginterferon-α 2b) should be considered. In myelofibrosis, continuous risk assessment and symptom burden assessment are essential in guiding treatment selection. Allogeneic hematopoietic stem cell transplantation (allo-HSCT) in MF should always be based on accurate risk stratification for disease-risk and post-HSCT outcome. Management of classical Ph-negative MPN entails accurate diagnosis, cytogenetic and molecular evaluation, risk stratification, and treatment strategies that are outcome-oriented (curative, disease modification, improvement of quality-of-life).

Bomedemstat as an investigative treatment for myeloproliferative neoplasms

INTRODUCTION

Myeloproliferative neoplasm (MPN) is a heterogeneous group of hematopoietic stem cell disorders characterized by clonal proliferation of one of more of the hematopoietic stem cell lineages. Clinical manifestations result from uncontrolled myeloproliferation, extramedullary hematopoiesis with splenomegaly and excessive inflammatory cytokine production. Currently available therapy improves hematologic parameters and symptoms but does not adequately address the underlying neoplastic biology. Bomedemstat has thus far demonstrated clinical efficacy and tolerability in the treatment of MPNs with recent evidence of impacting the malignant stem cell population.

AREAS COVERED

This review summarizes the mechanisms of action, pharmacokinetics and pharmacodynamics, safety and efficacy of bomedemstat in MPN with specific emphasis on essential thrombocythemia (ET) and myelofibrosis (MF).

EXPERT OPINION

In patients with MPNs, bomedemstat appears effective and well tolerated. The signs and symptoms of these diseases are managed as a reduction in the frequency of mutant cells was demonstrated in patients with ET and MF. Ongoing and planned studies of bomedemstat in MPN will establish the position of bomedemstat in MPNs and may help to redefine treatment endpoints of MPNs in the future.

Germline-somatic JAK2 interactions are associated with clonal expansion in myelofibrosis

Myelofibrosis is a rare myeloproliferative neoplasm (MPN) with high risk for progression to acute myeloid leukemia. Our integrated genomic analysis of up to 933 myelofibrosis cases identifies 6 germline susceptibility loci, 4 of which overlap with previously identified MPN loci. Virtual karyotyping identifies high frequencies of mosaic chromosomal alterations (mCAs), with enrichment at myelofibrosis GWAS susceptibility loci and recurrently somatically mutated MPN genes (e.g., JAK2). We replicate prior MPN associations showing germline variation at the 9p24.1 risk haplotype confers elevated risk of acquiring JAK2^V617F mutations, demonstrating with long-read sequencing that this relationship occurs in cis. We also describe recurrent 9p24.1 large mCAs that selectively retained JAK2^V617F mutations. Germline variation associated with longer telomeres is associated with increased myelofibrosis risk. Myelofibrosis cases with high-frequency JAK2 mCAs have marked reductions in measured telomere length – suggesting a relationship between telomere biology and myelofibrosis clonal expansion. Our results advance understanding of the germline-somatic interaction at JAK2 and implicate mCAs involving JAK2 as strong promoters of clonal expansion of those mutated clones.

Myelofibrosis is a risk factor for the development of Acute Myeloid Leukaemia. Here, the authors carry out an integrated genomic investigation of 933 myelofibrosis patients, and identified interactions between germline and somatic variation in patients who required haematopoietic cell transplantation.

JAK2 rs10974944 is associated with both V617F-positive and negative myeloproliferative neoplasms in a Vietnamese population: A potential genetic marker

The JAK2 gene encodes for a non‐receptor tyrosine kinase that plays a key role in the JAK/STAT signaling transfer pathway. Genetic polymorphisms of this gene have been indicated to be associated with myeloproliferative neoplasm‐associated thrombosis in recent studies. This research aimed to evaluate the association between the variant rs10974944 and different types of Myeloproliferative neoplasms disorders in the Vietnamese population. DNA samples were obtained from 172 essential thrombocythemia patients, 14 primary myelofibrosis patients, 76 polycythemia vera patients, and 192 healthy controls. The JAK2 rs10974944 and V617F genotypes were identified by the polymerase chain reaction‐restriction fragment length polymorphism genotyping and Sanger sequencing methods. Results showed that there was a strong association between rs10974944 and Myeloproliferative neoplasms phenotype (p < .0001) and the most significant association was observed in the recessive model of the mutant allele (G). The G allele carriers had a 1.74, 2.86, and 3.03 higher risk of getting essential thrombocythemia, primary myelofibrosis, and polycythemia vera, respectively. Interestingly, this effect of rs10974944 seemed to be independent of the JAK2 V617F genotype. The distribution of rs10974944 genotypes were significantly different between V617F‐positive and negative groups (p = .008). Moreover, the GG genotype of rs10974944 was observed to be associated with the risk of getting Myeloproliferative neoplasms both in JAK2 V617F‐positive group, and for the first time in JAK2 V617F‐negative patients. A systematic meta‐analysis in different populations strengthened the evidence regarding the correlation between rs10974944 and myeloproliferative neoplasm disorders. To sum up, our results suggested that rs10974944 can be used as a predisposition screening marker for predicting Myeloproliferative neoplasms susceptibility.

Targeting fibrosis, mechanisms and cilinical trials

Fibrosis is characterized by the excessive extracellular matrix deposition due to dysregulated wound and connective tissue repair response. Multiple organs can develop fibrosis, including the liver, kidney, heart, and lung. Fibrosis such as liver cirrhosis, idiopathic pulmonary fibrosis, and cystic fibrosis caused substantial disease burden. Persistent abnormal activation of myofibroblasts mediated by various signals, such as transforming growth factor, platelet-derived growth factor, and fibroblast growh factor, has been recongized as a major event in the occurrence and progression of fibrosis. Although the mechanisms driving organ-specific fibrosis have not been fully elucidated, drugs targeting these identified aberrant signals have achieved potent anti-fibrotic efficacy in clinical trials. In this review, we briefly introduce the aetiology and epidemiology of several fibrosis diseases, including liver fibrosis, kidney fibrosis, cardiac fibrosis, and pulmonary fibrosis. Then, we summarise the abnormal cells (epithelial cells, endothelial cells, immune cells, and fibroblasts) and their interactions in fibrosis. In addition, we also focus on the aberrant signaling pathways and therapeutic targets that regulate myofibroblast activation, extracellular matrix cross-linking, metabolism, and inflammation in fibrosis. Finally, we discuss the anti-fibrotic drugs based on their targets and clinical trials. This review provides reference for further research on fibrosis mechanism, drug development, and clinical trials.

Carfilzomib Enhances the Suppressive Effect of Ruxolitinib in Myelofibrosis

As the first FDA-approved tyrosine kinase inhibitor for treatment of patients with myelofibrosis (MF), ruxolitinib improves clinical symptoms but does not lead to eradication of the disease or significant reduction of the mutated allele burden. The resistance of MF clones against the suppressive action of ruxolitinib may be due to intrinsic or extrinsic mechanisms leading to activity of additional pro-survival genes or signalling pathways that function independently of JAK2/STAT5. To identify alternative therapeutic targets, we applied a pooled-shRNA library targeting ~5000 genes to a JAK2^V617F-positive cell line under a variety of conditions, including absence or presence of ruxolitinib and in the presence of a bone marrow microenvironment-like culture medium. We identified several proteasomal gene family members as essential to HEL cell survival. The importance of these genes was validated in MF cells using the proteasomal inhibitor carfilzomib, which also enhanced lethality in combination with ruxolitinib. We also showed that proteasome gene expression is reduced by ruxolitinib in MF CD34⁺ cells and that additional targeting of proteasomal activity by carfilzomib enhances the inhibitory action of ruxolitinib in vitro. Hence, this study suggests a potential role for proteasome inhibitors in combination with ruxolitinib for management of MF patients.

Spleen Stiffness Measurement by Using Shear-Wave Elastography as a Predictor of Progression to Secondary Myelofibrosis

OBJECTIVE

Polycythemia vera (PV) and essential thrombocythemia (ET) are chronic myeloproliferative diseases that can transform to secondary myelofibrosis (SMF). In this study, we evaluated spleen stiffness using shear-wave elastography (SWE) as a predictor of progression to SMF.

METHODS

Participants were grouped as healthy volunteers (HVs), PV/ET patients, and SMF patients. Participants' spleen sizes, spleen stiffness values, bone marrow fibrosis degrees, and the other parameters were evaluated. Spleen stiffness values and spleen sizes were compared between groups.

RESULTS

Of the 121 participants included in this study, 52 patients were HVs, 52 patients were PV and/or ET patients, and 17 patients were SMF patients. In terms of age and sex, there was no difference between groups. Splenic parenchymal stiffness median values by using SWE were found to be 0.82 m/s in HVs, 1.41 m/s in PV/ET patients, and 2.32 m/s in SMF patients (P < 0.001). In terms of median length of the spleen, the difference between groups was significant (P < 0.001). In addition, we found a significant positive correlation between spleen stiffness and bone marrow fibrosis degree (P < 0.001, r = 0.757). However, in multivariate analysis, there was no strong independent risk factor for spleen stiffness.

CONCLUSION

In this study, we showed that measurement of spleen stiffness using SWE can distinguish SMF from PV/ET patients and HVs. Therefore, we believe that SWE may be used as a noninvasive and easily accessible method to check the fibrotic progression of bone marrow in PV and ET patients to monitor the transformation to SMF, and enables to detect fibrosis in early phase.

Somatically acquired mutations in primary myelofibrosis: A case report and meta-analysis

Familial myeloproliferative disease (MPD) cases account for 7.6% of the global MPD cases. The present study reported 2 cases of primary myelofibrosis (PMF). The patients were two sisters; the older sister succumbed to the disease at the age of 37, whereas the younger sister maintained a stable disease status and gave birth to a son through in vitro fertilization. Genetic analysis of bone marrow DNA samples showed that both sisters carried a Janus kinase 2 (JAK2) V617F mutation, and the older sister also had a trisomy 8 chromosomal abnormality (47, XX, +8). A systematic literature search was also performed using PubMed, CNKI and Wanfang databases, to determine the association between JAK2 and PMF. Following comprehensive screening of the published literature, 19 studies were found to be eligible for the current meta-analysis. The results showed that JAK2 V617F was a risk factor of PMF, and no sex dimorphism was observed in JAK2 V617F mutation prevalence amongst all PMF cases. In addition, there was a lack of association between the JAK2 V617F mutation and PMF-related mortality.

Autoimmune Myelofibrosis in Sjögren's Syndrome: Report of a Case

Patient: Male, 49-year-old

Final Diagnosis: Autoimmune myelofibrosis

Symptoms: Bleeding

Medication:—

Clinical Procedure: Bone marrow biopsy

Specialty: Hematology

Myeloid diseases in the lung and pleura

Myeloid diseases detected as primary or secondary lesions in the lung and pleura are rare. Clinical presentations and radiographic results may vary significantly depending on the nature of the diseases. The most common diseases associated with lung and pleura involvement are myeloid sarcoma/acute myeloid leukemia (AML) and extramedullary hematopoiesis (EMH). AML typically represents localized involvement by systemic acute leukemia, while EMH is frequently secondary to underlying benign hematolymphoid disorders or myeloproliferative neoplasms. This review provides an overview of the pathogenesis, clinical presentations, radiologic/imaging studies, pathologic and genetic findings, and treatment/outcomes associated with myeloid diseases in the lung and pleura.

Primary analysis of JUMP, a phase 3b, expanded-access study evaluating the safety and efficacy of ruxolitinib in patients with myelofibrosis, including those with low platelet counts

Ruxolitinib is a potent Janus kinase (JAK) 1/JAK2 inhibitor approved for the treatment of myelofibrosis (MF). Ruxolitinib was assessed in JUMP, a large (N = 2233), phase 3b, expanded-access study in MF in countries without access to ruxolitinib outside a clinical trial, which included patients with low platelet counts (<100 × 10⁹ /l) and patients without splenomegaly - populations that have not been extensively studied. The most common adverse events (AEs) were anaemia and thrombocytopenia, but they rarely led to discontinuation (overall, 5·4%; low-platelet cohort, 12·3%). As expected, rates of worsening thrombocytopenia were higher in the low-platelet cohort (all grades, 73·2% vs. 53·5% overall); rates of anaemia were similar (all grades, 52·9% vs. 59·5%). Non-haematologic AEs, including infections, were mainly grade 1/2. Overall, ruxolitinib led to meaningful reductions in spleen length and symptoms, including in patients with low platelet counts, and symptom improvements in patients without splenomegaly. In this trial, the largest study of ruxolitinib in patients with MF to date, the safety profile was consistent with previous reports, with no new safety concerns identified. This study confirms findings from the COMFORT studies and supports the use of ruxolitinib in patients with platelet counts of 50-100 × 10⁹ /l. (ClinicalTrials.gov identifier NCT01493414).

Myelofibrosis in 2019: moving beyond JAK2 inhibition

Myelofibrosis (MF) is a myeloproliferative neoplasm characterized by ineffective clonal hematopoiesis, splenomegaly, bone marrow fibrosis, and the propensity for transformation to acute myeloid leukemia. The discovery of mutations in JAK2, CALR, and MPL have uncovered activated JAK-STAT signaling as a primary driver of MF, supporting a rationale for JAK inhibition. However, JAK inhibition alone is insufficient for long-term remission and offers modest, if any, disease-modifying effects. Given this, there is great interest in identifying mechanisms that cooperate with JAK-STAT signaling to predict disease progression and rationally guide the development of novel therapies. This review outlines the latest discoveries in the biology of MF, discusses current clinical management of patients with MF, and summarizes the ongoing clinical trials that hope to change the landscape of MF treatment.

Myeloid Sarcoma with Megakaryoblastic Differentiation Arising in the Conjunctiva

An 87-year-old woman not known to have either a lymphoma or leukemia developed a left multinodular, fish-flesh superior epibulbar and forniceal mass. A biopsy disclosed a blastic tumor with scattered multinucleated immature megakaryoblasts. Immunophenotyping of bone marrow cells revealed strong positivity for CD7, CD31, CD43, CD45, CD61, and CD117; CD71, myeloperoxidase, and lysozyme were also positive in scattered cells. Forty percent of the neoplastic cells were Ki-67 positive. Cytogenetic studies indicated a trisomy 8 (associated with worse prognosis) and a t(12; 17) translocation. Desmin, smooth muscle actin, pancytokeratin, CAM 5.2, adipophilin, tryptase, S100, SOX10, MART1, and E-cadherin were negative, ruling out a nonhematopoietic tumor. The conjunctival lesion was diagnosed as a myeloid sarcoma with megakaryoblastic differentiation, a rare variant. It probably arose from a myelodysplastic syndrome. This is the first case of its type to develop in the conjunctiva.

Bone marrow-specific loss of ABI1 induces myeloproliferative neoplasm with features resembling human myelofibrosis

Although the pathogenesis of primary myelofibrosis (PMF) and other myeloproliferative neoplasms (MPNs) is linked to constitutive activation of the JAK-STAT pathway, JAK inhibitors have neither curative nor MPN-stem cell-eradicating potential, indicating that other targetable mechanisms are contributing to the pathophysiology of MPNs. We previously demonstrated that Abelson interactor 1 (Abi-1), a negative regulator of Abelson kinase 1, functions as a tumor suppressor. Here we present data showing that bone marrow-specific deletion of Abi1 in a novel mouse model leads to development of an MPN-like phenotype resembling human PMF. Abi1 loss resulted in a significant increase in the activity of the Src family kinases (SFKs), STAT3, and NF-κB signaling. We also observed impairment of hematopoietic stem cell self-renewal and fitness, as evidenced in noncompetitive and competitive bone marrow transplant experiments. CD34⁺ hematopoietic progenitors and granulocytes from patients with PMF showed decreased levels of ABI1 transcript as well as increased activity of SFKs, STAT3, and NF-κB. In aggregate, our data link the loss of Abi-1 function to hyperactive SFKs/STAT3/NF-κB signaling and suggest that this signaling axis may represent a regulatory module involved in the molecular pathophysiology of PMF.

Recent advances in the diagnosis and management of primary myelofibrosis

Primary myelofibrosis (PMF) is a myeloproliferative neoplasm (MPN) in which dysregulation of the Janus kinase/signal transducers and activators of transcription (JAK/STAT) signaling pathways is the major pathogenic mechanism. Most patients with PMF carry a driver mutation in the JAK2, MPL (myeloproliferative leukemia), or CALR (calreticulin) genes. Mutations in epigenetic regulators and RNA splicing genes may also occur, and play critical roles in PMF disease progression. Based on revised World Health Organization diagnostic criteria for MPNs, both screening for driver mutations and bone marrow biopsy are required for a specific diagnosis. Clinical trials of JAK2 inhibitors for PMF have revealed significant efficacy for improving splenomegaly and constitutional symptoms. However, the currently available drug therapies for PMF do not improve survival. Although allogeneic stem cell transplantation is potentially curative, it is associated with substantial treatment-related morbidity and mortality. PMF is a heterogeneous disorder and decisions regarding treatments are often complicated, necessitating the use of prognostic models to determine the management of treatments for individual patients. This review focuses on the clinical aspects and outcomes of a cohort of Japanese patients with PMF, including discussion of recent advances in the management of PMF.

ASXL1 mutations in myeloid neoplasms: pathogenetic considerations, impact on clinical outcomes and survival

BACKGROUND

ASXL1 gene mutations include nonsense, missense, and frameshift mutations. Although their clinical significance is still debated, they may play an important role in the pathogenesis of several hematologic malignancies.

METHODS

Herein, we offer a comprehensive review on ASXL1 mutations, and link them with survival and clinical outcomes in patients with various myeloid neoplasms. Most relevant publications were identified through searching the PubMed/Medline database for articles published from inception to February 2016.

FINDINGS

In acute myeloid leukemia (AML), ASXL1 mutations tend to correlate with older age and male gender, and affect predominantly patients with secondary AML. De novo AML patients with ASXL1 mutations had significantly lower complete remission rates after standard high-dose chemotherapy and shorter survival. In chronic myelomonocytic leukemia and low- or intermediate-risk myelodysplastic syndromes, frameshift and nonsense mutations correlated with shorter survival and a higher risk of leukemic transformation. Overall survival was also shorter in primary myelofibrosis in the presence of ASXL1 mutations.

CONCLUSIONS

Further research on the role of ASXL1 mutations and therapeutic implications in neoplastic myeloid disorders is stringently needed. Given the relatively high prevalence of ASXL1 mutations, larger studies involving patients affected by these mutations will be feasible in the near future.

Recommendations on the use of ruxolitinib for the treatment of myelofibrosis

OBJECTIVES

Myelofibrosis (MF) is a severe disease, with decreased life expectancy and heavy symptom burden. Ruxolitinib is the only approved pharmacotherapy for the treatment of MF patients. In Belgium, ruxolitinib is only reimbursed for MF patients with splenomegaly for whom the disease is categorized as intermediate-2 or high risk. The improvement of symptoms without spleen volume reduction is not considered sufficient to continue treatment. The aim of this manuscript is to provide guidance for the safe and effective administration of ruxolitinib, considering the particularities of the Belgian reimbursement criteria.

METHODS

Our recommendations are based on a consensus reached during two meetings, where available data and observations derived from clinical experience were discussed.

RESULTS AND DISCUSSION

We recommend changing the current Belgian reimbursement conditions to include the evaluation of disease-related symptoms along with splenomegaly to decide whether ruxolitinib treatment should be continued or not. Indeed, the decrease in disease-related symptoms seems to be an equally important parameter as the decrease in splenic volume in the evaluation of the response to ruxolitinib. We also advocate for the treatment with ruxolitinib of MF patients in lower-risk categories with severe disease-related symptoms, as this drug could greatly improve their quality of life. Optimization of the ruxolitinib dose is recommended to avoid an unnecessary decrease in platelet count or hemoglobin that may jeopardize treatment continuation.

CONCLUSION

With the aim to optimize the treatment of MF patients, the Belgian regulation for ruxolitinib should be revised in terms of reimbursement criteria, dose titration, stopping rules, and patient follow-up.

Somatic Mutations in Philadelphia Chromosome-Negative Myeloproliferative Neoplasms

Myeloproliferative neoplasms (MPN) include polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF). MPN are characterized by clonal proliferation of myeloid progenitors leading to erythrocytosis, thrombocytosis, or leukocytosis, and risk of hemorrhagic and thrombotic events, as well as myelofibrosis and blast transformation. The discovery of somatic mutations in MPN, namely JAK2 V617F, JAK2 exon 12, MPL, and CALR mutations, has permitted a more specific approach to diagnosis and treatment. The prevalence of JAK2 V617F mutations is higher than 95% in PV, 50%-75% in ET and 40%-75% in PMF. JAK2 exon 12 mutations are specific of PV. A 20%-30% of patients with ET and PMF present a CALR mutation. The screening of mutations strengthens the diagnosis of MPN since 97% of MPN have at least 1 somatic mutation. Interestingly, different mutations grant different phenotype and prognosis. Of particular importance, CALR mutations grant a favorable prognosis in ET and PMF, while ASXL1 mutations confer a poorer outcome. In fact, the use of CALR/ASXL1 status for the prognostication of patients has increased clinical value and is now suggested for guidance of therapy in PMF. The increasing importance of mutations in the management of MPN warrants a more frequent revision of current diagnostic criteria and prognostic models and a better understanding of the mechanisms leading to MPN subset differentiation.

Effect of ruxolitinib therapy on the quality-of-life of Japanese patients with myelofibrosis

OBJECTIVES

Myelofibrosis (MF) is associated with a significant symptom burden that severely impacts patient quality-of-life (QoL). Ruxolitinib, a potent Janus kinase 1 (JAK1)/JAK2 inhibitor, led to substantial improvements in splenomegaly, MF-associated symptoms, and QoL in the phase 3 COMFORT studies, proving superior to placebo and best available therapy. This study evaluated the effect of ruxolitinib on symptoms and QoL in Japanese patients with MF.

METHODS

A pooled analysis of studies A2202 (NCT01392443) and AJP01 (NCT02087059) of ruxolitinib in Japanese patients with MF (n = 81) was conducted. Changes in total symptom score (TSS) and the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire Core 30 were summarized.

RESULTS

Most patients received a starting dose of 15 or 20 mg twice daily (BID) and had a final titrated dose of ≥10 mg BID. Overall, 67.7% (44/65) achieved a ≥50% reduction from baseline in TSS at week 24. Reductions in TSS were seen in every dose group; the greatest reductions occurred in patients with a final titrated dose of 20 or 25 mg BID. Improvements in QoL were seen in patients who achieved a ≥50% reduction in TSS. Generally, improvements in TSS and individual symptoms correlated with reductions in spleen size, with those having a ≥35% reduction in spleen volume having the greatest improvements.

CONCLUSIONS

Consistent with COMFORT-I, ruxolitinib provided substantial improvements in symptoms and QoL in Japanese patients with MF, with higher doses of ruxolitinib associated with better responses.

A Concise Update on Risk Factors, Therapy, and Outcome of Leukemic Transformation of Myeloproliferative Neoplasms

Myeloproliferative neoplasms (MPN) in chronic phase that evolve into blast phase (BP) hold a dismal prognosis and represent an urgent unmet clinical need. The mutational landscape of MPN-BP is distinct from de novo acute myeloid leukemia and offers insight into molecular mechanisms contributing to clonal evolution providing potential novel drug targets. A number of retrospective studies have identified patient- and disease-specific variables associated with increased risk of leukemic transformation (LT) of an underlying MPN. Several prognostic models have been developed to identify those MPN patients at highest risk for LT that may warrant early aggressive therapeutic intervention. Acute myeloid leukemia-type induction chemotherapy does not offer a significant survival benefit for MPN-BP unless followed by hematopoietic stem-cell transplantation. Unfortunately, most patients with MPN-BP are not candidates for hematopoietic stem-cell transplantation as a result of advanced age, competing comorbid conditions, or lack of an acceptable donor graft option. JAK2 inhibitor monotherapy is effective in reducing splenomegaly and symptom burden in the majority of treated patients with myelofibrosis, but LT can still occur. High-dose JAK2 inhibitor monotherapy appears tolerable but only modestly active in the treatment of MPN-BP. Current JAK2 inhibitor-based combination therapy approaches are supported by preclinical investigation and are currently being tested in multicenter clinical trials.

Intravascular large B-cell lymphoma associated with myelofibrosis: A case report

Myelofibrosis (MF) is often accompanied by chronic myeloid leukemia, hairy cell leukemia, or certain primary myeloproliferative neoplasms, but is rarely associated with lymphoid neoplasms. We herein describe a case of intravascular large B-cell lymphoma (IVLBCL) with MF. IVLBCL is a rare, aggressive type of extranodal B-cell lymphoma, defined by proliferation of lymphomatous cells within small-to medium-sized vessels. A 60-year-old woman was admitted to the hospital with anemia, thrombocytopenia and fever. Bone marrow biopsy findings included trilineage hematopoiesis, increased numbers of immature cells, markedly abnormal and enlarged megakaryocytes, and diffuse fibrosis in multiple focal areas throughout the entire bone marrow space. When the patient was first hospitalized, hepatosplenomegaly was not present. Although initially considered during differential diagnosis, an aggressive lymphoma could not be diagnosed prior to colonoscopy, which was conducted 4 weeks after admission. A biopsy of the terminal ileum revealed IVLBCL with cells with atypical nuclei. Immunophenotyping of the atypical large cells yielded a positive result for CD79a and negative results for terminal deoxynucleotidyl transferase, myeloperoxidase, CD3, CD10, CD20, B-cell lymphoma (Bcl)-2, Bcl-6 and cytomegalovirus. The patient was diagnosed with IVLBCL complicated by MF. This case may serve as a reminder that IVLBCL may be the cause of secondary MF.

miR-494-3p overexpression promotes megakaryocytopoiesis in primary myelofibrosis hematopoietic stem/progenitor cells by targeting SOCS6

Primary myelofibrosis (PMF) is a chronic Philadelphia-negative myeloproliferative neoplasm characterized by hematopoietic stem cell-derived clonal myeloproliferation, involving especially the megakaryocyte lineage. To better characterize how the altered expression of microRNAs might contribute to PMF pathogenesis, we have previously performed the integrative analysis of gene and microRNA expression profiles of PMF hematopoietic stem/progenitor cells (HSPCs), which allowed us to identify miR-494-3p as the upregulated microRNA predicted to target the highest number of downregulated mRNAs.To elucidate the role of miR-494-3p in hematopoietic differentiation, in the present study we demonstrated that miR-494-3p enforced expression in normal HSPCs promotes megakaryocytopoiesis. Gene expression profiling upon miR-494-3p overexpression allowed the identification of genes commonly downregulated both after microRNA overexpression and in PMF CD34+ cells. Among them, suppressor of cytokine signaling 6 (SOCS6) was confirmed to be a miR-494-3p target by luciferase assay. Western blot analysis showed reduced level of SOCS6 protein as well as STAT3 activation in miR-494-3p overexpressing cells. Furthermore, transient inhibition of SOCS6 expression in HSPCs demonstrated that SOCS6 silencing stimulates megakaryocytopoiesis, mimicking the phenotypic effects observed upon miR-494-3p overexpression. Finally, to disclose the contribution of miR-494-3p upregulation to PMF pathogenesis, we performed inhibition experiments in PMF HSPCs, which showed that miR-494-3p silencing led to SOCS6 upregulation and impaired megakaryocyte differentiation.Taken together, our results describe for the first time the role of miR-494-3p during normal HSPC differentiation and suggest that its increased expression, and the subsequent downregulation of its target SOCS6, might contribute to the megakaryocyte hyperplasia commonly observed in PMF patients.

Evaluation of the dose and efficacy of ruxolitinib in Japanese patients with myelofibrosis

Ruxolitinib, a potent JAK1/JAK2 inhibitor, improved splenomegaly and myelofibrosis-associated symptoms and prolonged survival compared with placebo and best available therapy in the phase 3 COMFORT studies. Although cytopenias were the most common adverse events associated with ruxolitinib treatment, a COMFORT-I analysis showed that they were managed effectively with dose modifications, without a negative impact on the efficacy of ruxolitinib. Subsequently, studies A2202 and AJP01 showed that ruxolitinib is an effective treatment for Japanese patients with myelofibrosis. We conducted a pooled analysis of these two studies (N = 81) to evaluate the association between ruxolitinib dose and changes in spleen volume or symptoms in Japanese patients. Most patients began treatment at 15 or 20 mg twice daily (BID); 70% received a final titrated dose ≥ 10 mg BID. Overall, 91% of patients exhibited spleen volume reductions; patients with final titrated doses ≥ 10 mg BID had larger spleen volume reductions. Similarly, 83% of patients showed improvements in symptom scores; those with a final titrated dose of 20 or 25 mg BID had the greatest reductions. Consistent with COMFORT-I, this pooled analysis indicates that, despite dose adjustments, ruxolitinib provides spleen and symptom control in Japanese patients, with higher doses associated with better responses.

Distribution and Impact of Comorbidities on Survival and Leukemic Transformation in Myeloproliferative Neoplasm-Associated Myelofibrosis: A Retrospective Cohort Study

BACKGROUND

We sought to describe the distribution and impact of comorbidities on outcomes in patients with myelofibrosis, a disease characterized by aberrant bone marrow function with eventual fibrosis. Comorbidities were scored using the Adult Comorbidity Evaluation-27 (ACE-27) and the Hematopoietic Cell Transplant Comorbidity Index (HCT-CI), in which a score ≥ 3 indicates severe comorbidities.

PATIENTS AND METHODS

We conducted a retrospective study of 306 patients with a confirmed diagnosis of myelofibrosis. Patients were seen from 1999 to 2014 with a median follow-up of 2 years. Multivariable Cox proportional hazards models were constructed to assess the impact of comorbidities on overall survival and leukemic transformation from the date of presentation to our center. A series of descriptive analyses were performed examining the distribution of comorbidities captured by the scales.

RESULTS

On multivariable survival analysis, an ACE-27 score of 3 was associated with an almost twofold increase in the risk of all-cause death (hazard ratio [HR] 1.95; 95% confidence interval [CI], 1.06-3.58; P = .03) compared with a lower score of 0 to 1. An HCT-CI score ≥ 3 was marginally significantly associated with an increased risk of all-cause death (HR 1.60; 95% CI 0.96-2.68; P = .07). ACE-27 captured a greater spectrum of cardiovascular and venous thrombotic disease. No impact of comorbidities on leukemic transformation was observed.

CONCLUSIONS

Although the presence of severe comorbidities was lower when assessed by ACE-27 (13%) compared with HCT-CI (23%), and the spectrums of comorbidities captured were different, the overall impact of severe comorbidities as assessed by both scales appears to be similar and associated with a survival disadvantage.

Hmga2 promotes the development of myelofibrosis in Jak2V617F knockin mice by enhancing TGF-β1 and Cxcl12 pathways

Myelofibrosis (MF) is a devastating blood disorder. The JAK2V617F mutation has been detected in ∼50% cases of MF. Elevated expression of high-mobility group AT hook 2 (HMGA2) has also been frequently observed in patients with MF. Interestingly, upregulation of HMGA2 expression has been found in association with the JAK2V617F mutation in significant cases of MF. However, the contribution of HMGA2 in the pathogenesis of MF remains elusive. To determine the effects of concurrent expression of HMGA2 and JAK2V617F mutation in hematopoiesis, we transduced bone marrow cells from Jak2^V617F knockin mice with lentivirus expressing Hmga2 and performed bone marrow transplantation. Expression of Hmga2 enhanced megakaryopoiesis, increased extramedullary hematopoiesis, and accelerated the development of MF in mice expressing Jak2^V617F Mechanistically, the data show that expression of Hmga2 enhances the activation of transforming growth factor-β1 (TGF-β1) and Cxcl12 pathways in mice expressing Jak2^V617F In addition, expression of Hmga2 causes upregulation of Fzd2, Ifi27l2a, and TGF-β receptor 2. Forced expression of Cxcl12, Fzd2, or Ifi27l2a increases megakaryocytic differentiation and proliferation in the bone marrow of Jak2^V617F mice, whereas TGF-β1 or Cxcl12 stimulation induces collagen deposition in the bone marrow mesenchymal stromal cells. Together, these findings demonstrate that expression of Hmga2 cooperates with Jak2^V617F in the pathogenesis of MF.

Detection of driver and subclonal mutations in myelofibrosis: clinical impact on pharmacologic and transplant based treatment strategies

INTRODUCTION

Myelofibrosis (MF) is the most aggressive form among Philadelphia negative (Ph-) myeloproliferative neoplasms (MPNs). In the last years, the mutational landscape of MF has expanded remarkably by the identification of additional recurrent mutations, called subclonal mutations. Areas covered: Here we describe the available data about the currently identified subclonal mutations and their prognostic value in MF patients. We also review the practical value of including such molecular information in available prognostic models for both outcome prediction and possibly treatment decision with regards to transplant indication. Lastly, we covered the available data on the application of molecular markers for minimal residual disease (MRD) monitoring after transplantation. Expert commentary: The demonstration of the prognostic value of additional mutations suggests to define this molecular profile at diagnosis and when an allogeneic transplant can be advised, particularly in younger patients. The presence of molecular markers might offer the possibility to evaluate the depth of remission and to monitor MRD after transplantation. Prospective clinical studies are needed to validate the use of this molecular data in the routine clinical practice.

The prognostic relevance of serum lactate dehydrogenase and mild bone marrow reticulin fibrosis in essential thrombocythemia

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

Hydroxycarbamine: from an Old Drug Used in Malignant Hemopathies to a Current Standard in Sickle Cell Disease

While hydroxycarbamide (hydroxyurea, HU) has less and fewer indications in malignant hemopathies, it represents the only widely used drug which modifies sickle cell disease pathogenesis. Clinical experience with HU for patients with sickle cell disease has been accumulated over the past 25 years in Western countries. The review of the literature provides increasing support for safety and efficacy in both children and adults for reducing acute vaso-occlusive events including pain episodes and acute chest syndrome. No increased incidence of leukemia and teratogenicity was demonstrated. HU has become the standard-of-care for sickle cell anemia but remains underused. Barriers to its use should be identified and overcome.

Treatment of rats with the JAK-2 inhibitor fedratinib does not lead to experimental Wernicke's encephalopathy

Recent clinical trials suggest that patients with myelofibrosis can develop Wernicke's encephalopathy (WE) when treated with fedratinib, a specific Janus kinase-2 (JAK-2) inhibitor. To investigate this issue, we have examined (1) if fedratinib can produce or alter the course of this disorder, (2) its effects on thiamine-dependent enzyme activity and thiamine status, and (3) its influence on the uptake of thiamine. Animals administered fedratinib for 28days at a comparable dose used to treat human cases of myelofibrosis showed no evidence of clinical signs of thiamine deficiency (TD). Rats treated with a combination of fedratinib and TD exhibited no neurological differences in their progress to the symptomatic stage when compared to thiamine-deficient animals only. Treatment with the JAK-2 inhibitor did not compromise erythrocyte transketolase activity, and thiamine status was not affected in a major way unlike animals with TD. In addition, treatment of cultured astrocytes with fedratinib did not diminish the uptake of thiamine into these cells. Our findings suggest that treatment with fedratinib does not lead to or alter the progress of TD, and do not support the notion that administration of this JAK-2 inhibitor directly results in the development of WE due to inhibition of thiamine transport. Known adverse effects of fedratinib involving compromised gastrointestinal function may be an important indirect contributing factor to previously reported cases of WE in patients with myelofibrosis.

Treatment of Myelofibrosis: A Moving Target

Myelofibrosis (MF) is a myeloproliferative neoplasm that presents either as a primary disease or evolves secondarily from polycythemia vera or essential thrombocythemia to post-polycythemia vera MF or post-essential thrombocythemia MF, respectively. Myelofibrosis is characterized by stem cell-derived clonal myeloproliferation, abnormal cytokine expression, bone marrow fibrosis, anemia, splenomegaly, extramedullary hematopoiesis, constitutional symptoms, cachexia, leukemic progression, and shortened survival. Therapeutic options for patients with MF have been limited to the use of cytoreductive agents, predominantly hydroxyurea; splenectomy and splenic irradiation for treatment of splenomegaly; and management of anemia with transfusions, erythropoiesis-stimulating agents, androgens, and immunomodulatory agents along with steroids. The only curative option is allogeneic stem cell transplantation (ASCT), which is associated with high morbidity and mortality risks. Recently, JAK (Janus kinase) inhibitor therapies have become available and proven to be palliative in primary MF patients with hydroxyurea-refractory splenomegaly and severe constitutional symptoms. The purpose of this article is to review the clinical features of MF; discuss different treatment strategies, including ASCT; and discuss the potential danger and benefit of using JAK inhibitors prior to ASCT.

The promise of Janus kinase inhibitors in the treatment of hematological malignancies

The Janus kinases (JAK) are a family of kinases that play an essential role in cytokine signaling and are implicated in the pathogenesis of autoimmune diseases and hematological malignancies. As a result, the JAKs have become attractive therapeutic targets. The discovery of a JAK2 point mutation (JAK2 V617F) as the main cause of polycythemia vera lead to the development and FDA approval of a JAK1/2 inhibitor, ruxolitinib, in 2011. This review focuses on the various JAK and associated components aberrations implicated in myeloproliferative neoplasms, leukemias, and lymphomas. In addition to ruxolitinib, other JAK inhibitors are currently being evaluated in clinical trials for treating hematological malignancies. The use of JAK inhibitors alone or in combination therapy should be considered as a way to deliver targeted therapy to patients.

Clinical features and outcomes of patients with primary myelofibrosis in Japan: report of a 17-year nationwide survey by the Idiopathic Disorders of Hematopoietic Organs Research Committee of Japan

We conducted a 17-year nationwide survey (1999-2015) to elucidate the clinical outcomes of patients with primary myelofibrosis (PMF) in Japan. Questionnaires were sent annually to approximately 500 hematology departments. Newly diagnosed patients with PMF were enrolled in this study, and were followed up annually to collect prognostic information. Approximately 50 patients were enrolled per year, yielding a total of 780 patients with PMF included in this study. The median age at diagnosis was 66 years. At the time of analysis, the median survival duration was 47 months, and the 3-year overall survival rate was 59 %. Infection and disease transformation into acute leukemia were the most frequent causes of death. Of the proposed prognostic models for predicting the outcomes of PMF patients in Japan, the Dynamic International Prognostic Scoring System of PMF plus model was the most feasible. Forty-three patients received allogeneic hematopoietic stem cell transplantation (alloSCT) at a median of 343 days after diagnosis. This treatment significantly prolonged the survival of PMF patients, and the 3-year overall survival rate after first alloSCT was 84 %. A long-term registration study is required for further evaluation of prognosis and the impact of treatments on survival.

Myeloproliferative Neoplasms: Molecular Drivers and Therapeutics

Activating mutations in genes that drive neoplastic cell growth are numerous and widespread in cancer, and specific genetic alterations are associated with certain types of cancer. For example, classic myeloproliferative neoplasms (MPNs) are hematopoietic stem cell disorders that affect cells of the myeloid lineage, including erythrocytes, platelets, and granulocytes. An activating mutation in the JAK2 tyrosine kinase is prevalent in these diseases. In MPN patients that lack such a mutation, other genetic changes that lead to activation of the JAK2 signaling pathway are present, indicating deregulation of JAK2 signaling plays an etiological driving role in MPNs, a concept supported by significant evidence from in vivo experimental MPN systems. Thus, small molecules that inhibit JAK2 activity are ideal drugs to impede the progression of disease in MPN patients. However, even though JAK inhibitors provide significant symptomatic relief, they have failed as a remission-inducing therapy. Nonetheless, the progress made understanding the molecular etiology of MPNs since 2005 is significant and has provided insight for the development and testing of novel molecular targeted therapeutic approaches. The current understanding of driver mutations in MPNs and an overview of current and potential therapeutic strategies for MPN patients will be discussed.

Pharmacologic management of myelofibrosis

Myelofibrosis is a BCR-ABL-negative myeloproliferative neoplasm characterized by abnormal hematopoiesis. Alterations to the Janus kinase-signal transducer and activator of transcription pathway result in dysregulation of gene transcription and cell proliferation. Patients with symptomatic myelofibrosis present with a variety of signs and symptoms including, but not limited to myelosuppression, marked splenomegaly, abdominal discomfort, fatigue, and blood transfusion-dependence. Traditional myelosuppressive therapies including hydroxyurea, azacitidine, and cladribine aim to reduce constitutional symptoms and control the burden of disease. Immunomodulators can potentially reverse anemia associated with myelofibrosis, but are poorly tolerated by most patients. The novel Janus kinase 2 (JAK2) inhibitor, ruxolitinib, has demonstrated marked improvements to constitutional symptoms and splenomegaly. While survival benefit has not yet been demonstrated, continued research into pharmacologic management of myelofibrosis offers the promise of altering the course of disease progression.

Prognostic value of CALR vs. JAK2V617F mutations on splenomegaly, leukemic transformation, thrombosis, and overall survival in patients with primary fibrosis: a meta-analysis

The understanding of genetic basis for Philadelphia-negative myeloproliferative neoplasm (MPN) has got much progress in recent years. But the effect of CALR vs. JAK2V617F mutations on the clinical progression and prognosis of primary fibrosis (PMF) remains relatively obscure. In this meta-analysis, we searched Pubmed, Embase, and Web of Science databases for observational studies published until February 2016. Researches that evaluated CALR vs. JAK2V617F mutations on PMF-relevant complications (splenomegaly, leukemic transformation, or thrombosis) and overall survival were selected. Pooled adjust odds ratio (OR), hazard risk (HR), and the corresponding 95 % confidence intervals (CI) were calculated for the CALR-mutant versus the JAK2-mutant categories. Twelve studies involving 435 CALR-mutated and 1116 JAK2V617F PMF patients were analyzed. CALR-mutated patients displayed a lower risk of splenomegaly (OR 0.47, 95 % CI 0.29-0.78) and thrombosis (OR 0.52, 95 % CI 0.29-0.92) but showed no significant difference in the risk of leukemic transformation (OR 0.90, 95 % CI 0.55-1.47) when compared with JAK2-mutated patients. CALR mutation favorably affected overall survival while JAK2 mutation led to poorer survival rate (HR 2.58, 95 % CI 2.08-3.20). This meta-analysis confirmed that a genetic classification of PMF by CALR and JAK2 mutations carried significant prognostic relevance.

Increased plasma nicotinamide phosphoribosyltransferase is associated with a hyperproliferative phenotype and restrains disease progression in MPN-associated myelofibrosis

Myeloproliferative neoplasm (MPN)-associated myelofibrosis is a clonal, neoplastic disorder of the hematopoietic stem cells, in which inflammation and immune dysregulation play an important role. Extracellular nicotinamide phosphoribosyltransferase (eNAMPT), also known as visfatin, is a cytokine implicated in a number of inflammatory and neoplastic diseases. Here plasma levels of eNAMPT in patients with MPN-associated myelofibrosis and their effects on disease phenotype and outcomes were examined. The concordance of eNAMPT levels with the marker of general inflammation high-sensitivity C-reactive protein (hs-CRP) was also studied. A total of 333 MPN-associated myelofibrosis patients (187 males and 146 females) and 31 age- and gender-matched normal-weight healthy subjects were enrolled in the study main body. Levels of eNAMPT and hs-CRP were simultaneously assayed in 209 MPN-associated myelofibrosis patients. Twenty-four polycythemia vera or essential thrombocythemia patients were used as controls. eNAMPT was over expressed in MPN-associated myelofibrosis, and eNAMPT expression was correlated with higher white blood cell count, higher hemoglobin, and higher platelet count, suggesting that eNAMPT is an indispensable permissive agent for myeloproliferation of MPN-associated myelofibrosis. The lack of correlation between eNAMPT and hs-CRP revealed that eNAMPT in MPN-associated myelofibrosis does not behave as a canonical inflammatory cytokine. In addition, higher levels of eNAMPT predicted longer time to blast transformation, and protected against progression toward thrombocytopenia and large splenomegaly. In conclusion, in MPN-associated myelofibrosis high levels of eNAMPT mark the myeloproliferative potential and, at variance with a high number of cancers, are protective against disease progression. Am. J. Hematol. 91:709-713, 2016. © 2016 Wiley Periodicals, Inc.