Synergetic effect of Azacitidine and Sorafenib in treatment of a case of myeloid neoplasm with sole chromosomal abnormality t(8;22)(p11.2;q11.2)/BCR-FGFR1 rearrangement.

The sole t(8;22)(p11.2;q11.2)/BCR- FGFR1 chromosomal abnormality formerly known as aCML is an extremely rare disease entity with a history of rapid progression. Though patients resemble phenotypically chronic myeloid leukemia, the treatment of patients with sole BCR-FGFR1 rearrangement are still challenging for clinicians due to rapid progressive nature and unavailability of uniform treatment guidelines. In present case study, we describe a case of myeloid neoplasm with sole chromosomal abnormality of t(8;22)(p11.2;q11.2)/BCR-FGFR1 rearrangement which is successfully managed by Sorafenib with Azacitidine. Hence our case report suggests that combination of Sorafenib and Azacitidine treatment is effective in sole BCR-FGFR1 rearrangement, however this combination therapy should be studied in large clinical trials.

A pilot study examining the efficacy of hochuekkito for improving quality of life in patients with myeloproliferative neoplasms.

BACKGROUND: The prognosis of Philadelphia chromosome-negative myeloproliferative neoplasms is relatively favorable, but the quality of life can be severely affected by myeloproliferative neoplasm-related symptoms such as fatigue, pruritus, night sweats, bone pain, fever and weight loss. In this study, we administered hochuekkito, a traditional herbal medicine, to patients with myeloproliferative neoplasms and investigated whether there was a reduction in myeloproliferative neoplasm-related symptoms. METHODS: We conducted a randomized parallel-group pilot study. Patients were assigned to a hochuekkito administration or non-hochuekkito administration group. Myeloproliferative neoplasm-related symptoms based on Myeloproliferative Neoplasm Symptom Assessment Form total symptom score and European Organization for Research and Treatment of Cancer Quality of Life Questionnaire-Core 30 were examined before hochuekkito administration and 4 and 8 weeks after administration. RESULTS: Among the 42 patients included in the analysis, 21 were assigned to the hochuekkito group and 21 were assigned to the control group. After administering hochuekkito, the median values of Myeloproliferative Neoplasms Symptom Assessment Form total symptom score at 4 and 8 weeks in the hochuekkito group demonstrated a decreasing trend; however, the difference between the two groups was not significant. CONCLUSIONS: In this study, we were unable to demonstrate significant differences between the hochuekkito and control groups in terms of the efficacy of hochuekkito in treating myeloproliferative neoplasm-related symptoms. However, there were cases that presented prominent improvement in symptoms in the hochuekkito group. The only reported adverse event was grade 1 impaired hepatic function. Therefore, hochuekkito might be a therapeutic option for patients with severely affected quality of life due to myeloproliferative neoplasm-related symptoms.

Inferring the dynamics of mutated hematopoietic stem and progenitor cells induced by IFNα in myeloproliferative neoplasms.

Classical BCR-ABL-negative myeloproliferative neoplasms (MPNs) are clonal disorders of hematopoietic stem cells (HSCs) caused mainly by recurrent mutations in genes encoding JAK2 (JAK2), calreticulin (CALR), or the thrombopoietin receptor (MPL). Interferon α (IFNα) has demonstrated some efficacy in inducing molecular remission in MPNs. To determine factors that influence molecular response rate, we evaluated the long-term molecular efficacy of IFNα in patients with MPN by monitoring the fate of cells carrying driver mutations in a prospective observational and longitudinal study of 48 patients over more than 5 years. We measured the clonal architecture of early and late hematopoietic progenitors (84 845 measurements) and the global variant allele frequency in mature cells (409 measurements) several times per year. Using mathematical modeling and hierarchical Bayesian inference, we further inferred the dynamics of IFNα-targeted mutated HSCs. Our data support the hypothesis that IFNα targets JAK2V617F HSCs by inducing their exit from quiescence and differentiation into progenitors. Our observations indicate that treatment efficacy is higher in homozygous than heterozygous JAK2V617F HSCs and increases with high IFNα dose in heterozygous JAK2V617F HSCs. We also found that the molecular responses of CALRm HSCs to IFNα were heterogeneous, varying between type 1 and type 2 CALRm, and a high dose of IFNα correlates with worse outcomes. Our work indicates that the long-term molecular efficacy of IFNα implies an HSC exhaustion mechanism and depends on both the driver mutation type and IFNα dose.

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 JAK2V617F 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 JAK2V617F 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 JAK2V617F 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 JAK2V617F and downstream STAT3/5 transcription factors. ZT55 inhibited the proliferation of the JAK2V617F-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 JAK2V617F 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.

Epigenetic Modifiers in Myeloid Malignancies: The Role of Histone Deacetylase Inhibitors.

Myeloid hematological malignancies are clonal bone marrow neoplasms, comprising of acute myeloid leukemia (AML), the myelodysplastic syndromes (MDS), chronic myelomonocytic leukemia (CMML), the myeloproliferative neoplasms (MPN) and systemic mastocytosis (SM). The field of epigenetic regulation of normal and malignant hematopoiesis is rapidly growing. In recent years, heterozygous somatic mutations in genes encoding epigenetic regulators have been found in all subtypes of myeloid malignancies, supporting the rationale for treatment with epigenetic modifiers. Histone deacetylase inhibitors (HDACi) are epigenetic modifiers that, in vitro, have been shown to induce growth arrest, apoptotic or autophagic cell death, and terminal differentiation of myeloid tumor cells. These effects were observed both at the bulk tumor level and in the most immature CD34⁺38- cell compartments containing the leukemic stem cells. Thus, there is a strong rationale supporting HDACi therapy in myeloid malignancies. However, despite initial promising results in phase I trials, HDACi in monotherapy as well as in combination with other drugs, have failed to improve responses or survival. This review provides an overview of the rationale for HDACi in myeloid malignancies, clinical results and speculations on why clinical trials have thus far not met the expectations, and how this may be improved in the future.

Diagnostic, Prognostic, and Predictive Utility of Recurrent Somatic Mutations in Myeloid Neoplasms.

The classification and risk stratification of myeloid neoplasms, including acute myeloid leukemia, myelodysplastic syndromes, myelodysplastic syndromes/myeloproliferative neoplasms, and myeloproliferative neoplasms, have increasingly been guided by molecular genetic abnormalities. Gene expression analysis and next-generation sequencing have led to the ever increasing discovery of somatic gene mutations in myeloid neoplasms. Mutations have been identified in genes involved in epigenetic modification, RNA splicing, transcription factors, DNA repair, and the cohesin complex. These new somatic/acquired gene mutations have refined the classification of myeloid neoplasms and have been incorporated into the 2016 update of the World Health Organization (WHO) classification and the National Comprehensive Cancer Network guidelines. They have also been helpful in the development of new targeted therapeutic agents. In the present review, we describe the clinical utility of recently identified, clinically important gene mutations in myeloid neoplasms, including those incorporated in the 2016 update of the WHO classification.

The Development and Use of Janus Kinase 2 Inhibitors for the Treatment of Myeloproliferative Neoplasms.

Following the discovery of the JAK2V617F mutation, Janus kinase (JAK) 2 inhibitors were developed as rationally designed therapy in myeloproliferative neoplasms (MPNs). Although JAK2 inhibitors have clinical efficacy in MPN, they are not clonally selective for the JAK2V617F-mutant cells. Because activated JAK-signal transducer and activator of transcription (STAT) signaling is a common feature of MPN, JAK2 inhibitors are efficacious regardless of the specific MPN phenotypic driver mutation. The Food and Drug Administration approved the JAK1/JAK2 inhibitor, ruxolitinib, for the treatment of myelofibrosis and polycythemia vera. Additional JAK2 inhibitors are currently in advanced phased clinical trials.

Tyrosine Kinase Inhibitors and Therapeutic Antibodies in Advanced Eosinophilic Disorders and Systemic Mastocytosis.

World Health Organization-defined myeloproliferative neoplasms share a common pathobiologic theme of constitutive activation of tyrosine kinases (TKs). While myeloid/lymphoid neoplasms with eosinophilia and rearrangement of PDGFRA or PDGFRB exhibit exquisite responsiveness to imatinib, other eosinophilic disorders such as chronic eosinophilic leukemia--not otherwise specified (CEL-NOS) and idiopathic hypereosinophilic syndrome (HES) lack recurrent gene mutations or known druggable targets. In systemic mastocytosis (SM), KIT D816V is identified in ∼ 90% of patients, but demonstrates imatinib resistance. Recently, the multikinase/KIT inhibitor midostaurin (PKC412) has demonstrated encouraging activity in patients with advanced SM, and selective KIT D816V inhibitors are entering clinical development. Pre-clinical rationale also exists for use of small molecule inhibitors of TK-linked pathways (e.g., BTK, JAK-STAT, PI3K/AKT, and FGFR1) that are implicated in normal or dysregulated signaling in eosinophils or mast cells. A complementary therapeutic approach is the use of naked antibody (e.g., mepolizumab and alemtuzumab) or antibody-based drug immunoconjugates (brentuximab vedotin) against targets expressed on the surface of eosinophils or mastocytes that can block proliferation and/or induce apoptosis of these cells. Ultimately, biologic and molecular characterization of eosinophilia and SM cases will help to optimize selection of TK inhibitors or therapeutic antibodies for individual patients.

Screening of drugs to treat 8p11 myeloproliferative syndrome using patient-derived induced pluripotent stem cells with fusion gene CEP110-FGFR1.

Induced pluripotent stem (iPS) cells provide powerful tools for studying disease mechanisms and developing therapies for diseases. The 8p11 myeloproliferative syndrome (EMS) is an aggressive chronic myeloproliferative disorder (MPD) that is caused by constitutive activation of fibroblast growth factor receptor 1. EMS is rare and, consequently, effective treatment for this disease has not been established. Here, iPS cells were generated from an EMS patient (EMS-iPS cells) to assist the development of effective therapies for EMS. When iPS cells were co-cultured with murine embryonic stromal cells, EMS-iPS cells produced more hematopoietic progenitor and hematopoietic cells, and CD34+ cells derived from EMS-iPS cells exhibited 3.2-7.2-fold more macrophage and erythroid colony forming units (CFUs) than those derived from control iPS cells. These data indicate that EMS-iPS cells have an increased hematopoietic differentiation capacity, which is characteristic of MPDs. To determine whether a tyrosine kinase inhibitor (TKI) could suppress the increased number of CFUs formed by EMS-iPS-induced CD34+ cells, cells were treated with one of four TKIs (CHIR258, PKC 412, ponatinib, and imatinib). CHIR258, PKC 412, and ponatinib reduced the number of CFUs formed by EMS-iPS-induced CD34+ cells in a dose-dependent manner, whereas imatinib did not. Similar effects were observed on primary peripheral blood cells (more than 90% of which were blasts) isolated from the patient. This study provides evidence that the EMS-iPS cell line is a useful tool for the screening of drugs to treat EMS and to investigate the mechanism underlying this disease.

What is the Incidence of Kidney Stones after Chemotherapy in Patients with Lymphoproliferative or Myeloproliferative Disorders?

Introduction This study describes the incidence and risk factors of de novo nephrolithiasis among patients with lymphoproliferative or myeloproliferative diseases who have undergone chemotherapy. Materials and Methods From 2001 to 2011, patients with lymphoproliferative or myeloproliferative disorders treated with chemotherapy were retrospectively identified. The incidence of image proven nephrolithiasis after chemotherapy was determined. Demographic and clinical variables were recorded. Patients with a history of nephrolithiasis prior to chemotherapy were excluded. The primary outcome was incidence of nephrolithiasis, and secondary outcomes were risk factors predictive of de novo stone. Comparative statistics were used to compare demographic and disease specific variables for patients who developed de novo stones versus those who did not. Results A total of 1,316 patients were identified and the incidence of de novo nephrolithiasis was 5.5% (72/1316; symptomatic stones 1.8% 24/1316). Among patients with nephrolithiasis, 72.2% had lymphoproliferative disorders, 27.8% had myeloproliferative disorders, and 25% utilized allopurinol. The median urinary pH was 5.5, and the mean serum uric acid, calcium, potassium and phosphorus levels were 7.5, 9.6, 4.3, and 3.8 mg/dL, respectively. In univariate analysis, mean uric acid (p=0.013), calcium (p<0.001)), and potassium (p=0.039) levels were higher in stone formers. Diabetes mellitus (p<0.001), hypertension (p=0.003), and hyperlipidemia (p<0.001) were more common in stone formers. In multivariate analysis, diabetes mellitus, hyperuricemia, and hypercalcemia predicted stone. Conclusions We report the incidence of de novo nephrolithiasis in patients who have undergone chemotherapy. Diabetes mellitus, hyperuricemia, and hypercalcemia are patient-specific risk factors that increase the odds of developing an upper tract stone following chemotherapy. .

Janus kinase inhibitors for the treatment of myeloproliferative neoplasms.

INTRODUCTION: Disordered signaling through the JAK/STAT pathway is a hallmark of myeloproliferative neoplasms (MPNs). Targeted therapies that inhibit and regulate this pathway are reasonable strategies for disease management. Only one JAK1/JAK2 inhibitor has gained FDA approval for treatment of myelofibrosis. Despite significant reductions in splenomegaly and disease-associated symptoms, additional agents are necessary to manage disease in those that do not respond. AREAS COVERED: A review of the currently available literature and meeting abstracts for JAK inhibitors in myeloproliferative neoplasms identified studies aimed at improving outcomes and establishing alternative therapies in MPNs. Development of specific JAK inhibitors and ongoing trials involving ruxolitinib, CYT387, SAR302503, CEP701, SB 1518, XL-019, LY2784544, BMS-911453, NS-018, AZD1480 and INCB039110 are reviewed. EXPERT OPINION: The identification of JAK2V617F mutation and its link to MPNs has revolutionized treatment options. Resultant research in targeting the JAK/STAT pathway led to the approval of ruxolitinib, a JAK1/JAK2 inhibitor with activity in MPNs. While ruxolitinib produces durable reductions in splenomegaly and improvement of symptoms, and prolongs survival, there is room for new and more specific agents to be developed. Minimizing toxicity and avoiding drug resistance are challenges that lie ahead. Combining agents with different mechanisms seems to be a rational strategy.

Preclinical models for drug selection in myeloproliferative neoplasms.

The discovery that an abnormally activated JAK-STAT signaling pathway is central to the pathogenesis of myeloproliferative neoplasms has promoted the clinical development of small-molecule JAK2 inhibitors. These agents have shown remarkable efficacy in disease control, but do not induce molecular remission; on the other hand, interferon holds the promise to target the putative hematopoietic progenitor cell initiating the disease. The presence of additional molecular abnormalities indicates a high molecular complexity of myeloproliferative neoplasms, and the need for simultaneously targeting different targets. Several drugs are currently under study as single agents and in combination. This review briefly describes the several in vitro and in vivo models of myeloproliferative neoplasms that are being used as preclinical models for drug development.

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.

New generation small-molecule inhibitors in myeloproliferative neoplasms.

PURPOSE OF REVIEW: Myeloproliferative neoplasms (MPNs) are diseases that carry the JAK2 (V617F) mutation in about 70% of the patients. The purpose of this review is to describe the recent advances in the therapy of MPNs with JAK2 inhibitors. RECENT FINDINGS: Many drugs are now under investigations targeting different pathways critical for MPN development, such as the JAK-STAT (JAK2 inhibitors: INCB018424 or ruxolitinib, TG101348 or SAR302503, CYT387, SB1518, CEP701 and LY2784544) and the PI3K/AKT/mTOR (everolimus) pathways, or act through remodeling of chromatin with a key role in epigenetics (givinostat, panobinostat and vorinostat). The most relevant effects were spleen size reduction and relief of constitutional symptoms. SUMMARY: Patients who might benefit from JAK2 inhibitors in clinical practice are mostly those with splenomegaly or with constitutional symptoms. We should alert patients with lower hemoglobin levels that these therapies might, although temporarily, favor the need for red blood cell transfusions.

Hydroxyurea: a key player in cancer chemotherapy.

Hydroxyurea (HU) is a simple organic compound currently used as a cancer chemotherapeutic agent. It acts specifically on the S-phase of the cell cycle by inhibiting the enzyme ribonucleoside diphosphate reductase, thereby hindering the reductive conversion of ribonucleotides to deoxyribonucleotides and thus limiting de novo DNA synthesis. HU is employed in hemotological settings as a first-line treatment of myeloproliferative disorders, such as polycythemia vera, essential thrombocythemia and primary myelofibrosis, apart from having a vital role in combination therapy for management of malignant melanoma, head and neck cancers and brain tumors. It offers an advantage that the patient may take this drug on an ambulatory basis with minimum clinical toxicity, while some of its limitations include gastrointestinal disturbance and bone marrow depression. This review will summarize and present the overall effects of HU and its combination therapy as an anticancer agent.

The Jak2 inhibitor, G6, alleviates Jak2-V617F-mediated myeloproliferative neoplasia by providing significant therapeutic efficacy to the bone marrow.

We recently developed a Janus kinase 2 (Jak2) small-molecule inhibitor called G6 and found that it inhibits Jak2-V617F-mediated pathologic cell growth in vitro, ex vivo, and in vivo. However, its ability to inhibit Jak2-V617F-mediated myeloproliferative neoplasia, with particular emphasis in the bone marrow, has not previously been examined. Here, we investigated the efficacy of G6 in a transgenic mouse model of Jak2-V617F-mediated myeloproliferative neoplasia. We found that G6 provided therapeutic benefit to the peripheral blood as determined by elimination of leukocytosis, thrombocytosis, and erythrocytosis. G6 normalized the pathologically high plasma concentrations of interleukin 6 (IL-6). In the liver, G6 eliminated Jak2-V617F-driven extramedullary hematopoiesis. With respect to the spleen, G6 significantly reduced both the splenomegaly and megakaryocytic hyperplasia. In the critically important bone marrow, G6 normalized the pathologically high levels of phospho-Jak2 and phospho-signal transducer and activator of transcription 5 (STAT5). It significantly reduced the megakaryocytic hyperplasia in the marrow and completely normalized the M/E ratio. Most importantly, G6 selectively reduced the mutant Jak2 burden by 67%on average, with virtual elimination of mutant Jak2 cells in one third of all treated mice. Lastly, clonogenic assays using marrow stem cells from the myeloproliferative neoplasm mice revealed a time-dependent elimination of the clonogenic growth potential of these cells by G6. Collectively, these data indicate that G6 exhibits exceptional efficacy in the peripheral blood, liver, spleen, and, most importantly, in the bone marrow, thereby raising the possibility that this compound may alter the natural history of Jak2-V617F-mediated myeloproliferative neoplasia.

JAK inhibitors in myeloproliferative neoplasms: rationale, current data and perspective.

JAK-STAT is an appealing but also problematic drug target in BCR-ABL1-negative myeloproliferative neoplasms (MPN) - it is appealing because the majority of patients with MPN harbor gain-of-function JAK2 or MPL mutations - it is problematic because currently available JAK inhibitors do not distinguish between oncogenic and physiologic JAK-STAT activation. Furthermore, JAK-STAT-relevant mutations in MPN do not always constitute the predominant or ancestral mutant clone. Such complexities undermine the value of JAK-STAT as a robust drug target in MPN and partly explain the hitherto lack of histologic or molecular remissions associated with currently available JAK inhibitors. Most of these drugs were, however, effective in alleviating constitutional symptoms and reducing spleen size; the mechanism of action in this instance includes drug-induced down-regulation of inflammatory cytokine activity. In addition, non-specific myelosuppression contributes to both their salutary and detrimental effects on peripheral blood count. Non-hematologic side effects include gastrointestinal disturbances, asymptomatic elevation of liver and pancreatic enzymes, peripheral neuropathy and hyperacute relapse of symptoms during treatment interruption. It is our impression that many more JAK inhibitors need to be evaluated in order to identify the best-in-class in terms of efficacy, toxicity and suitability for future combination treatment programs.

Danazol therapy combined with intermittent application of chemotherapy induces lasting remission in myeloproliferative disorder (MPD): an alternative for the elderly with advanced MPD.

There is no good alternative therapy available for elderly patients with advanced myeloproliferative disorders (MPD) who failed on conventional therapies and are not candidates for bone marrow transplant. We report here an effective therapy that induced exceptionally long-lasting remissions and improved quality of life. Eighteen elderly patients (mean age: 70·6 years) (16 myelofibrosis and 2 thrombocythemia) who had failed on conventional therapies were treated. Danazol was administered daily at 200-800 mg throughout the study. Chemotherapy was applied intermittently as needed to reduce spleen size and blood counts. Busulfan (2-4 mg/day) was used most often and 6-mercaptopurine (6-MP) (50-100 mg/day) and/or cytarabine (100-200 mg/m(2)) if the white blood cell (WBC) count rose rapidly. When MPD stabilized, chemotherapy was discontinued and dosage of danazol was reduced. Therapy was well tolerated. Overall, 61% of patients responded with unexpectedly long-lasting remissions and improved quality of life. Three (17%) had excellent (E) response, defined by normalization of blood counts and non-palpable spleen, while eight (44%) had good (G) response, defined by rise of Hct by ≥7% and ≥50% reduction of spleen. Mean duration of remission was 45 months (10-78 months) in E responders and 11 months in G responders (2-22 months). This regimen offers a safe and effective alternative for advanced MPD in the elderly.