A primer on genomic and epigenomic alterations in the myeloproliferative neoplasms

A lymphatic-absorbed multi-targeted kinase inhibitor for myelofibrosis therapy

Activation of compensatory signaling nodes in cancer often requires combination therapies that are frequently plagued by dose-limiting toxicities. Intestinal lymphatic drug absorption is seldom explored, although reduced toxicity and sustained drug levels would be anticipated to improve systemic bioavailability. A potent orally bioavailable multi-functional kinase inhibitor (LP-182) is described with intrinsic lymphatic partitioning for the combined targeting of phosphoinositide 3-kinase (PI3K) and mitogen-activated protein kinase (MAPK) signaling pathways without observable toxicity. We demonstrate selectivity and therapeutic efficacy through reduction of downstream kinase activation, amelioration of disease phenotypes, and improved survival in animal models of myelofibrosis. Our further characterization of synthetic and physiochemical properties for small molecule lymphatic uptake will support continued advancements in lymphatropic therapy for altering disease trajectories of a myriad of human disease indications.

Combination therapies simultaneously inhibiting different therapeutic targets in cancer is challenged by individual pharmacokinetic profiles. Here, the authors generate an orally provided multi-targeted kinase inhibitor that is lymphatic absorbed and increases survival in a murine model of myelofibrosis.

Suspicions regarding the genetic inheritance of acute lymphoblastic leukemia in patients with down syndrome

Children with Down syndrome (DS) are at markedly increased risk for acute lymphoblastic leukaemia (ALL). DS is caused by trisomy of chromosome 21 affecting approximately 1 in 732 newborns in the USA. ALL is the most common cancer in children and constitutes approximately 25% of cancer diagnoses among children under the age of 15. Different protocols for treatment and management of paediatric ALL are available; however, DS children with ALL (DS-ALL) have increased risk of therapy-related toxicity compared to those without DS. Herein, we summarize the available literature on inherited predisposition for ALL, and possibilities for molecular therapy and treatment for DS-ALL patients.

Murine Modeling of Myeloproliferative Neoplasms

Myeloproliferative neoplasms, such as polycythemia vera, essential thrombocythemia, and primary myelofibrosis, are bone marrow disorders that result in the overproduction of mature clonal myeloid elements. Identification of recurrent genetic mutations has been described and aid in diagnosis and prognostic determination. Mouse models of these mutations have confirmed the biologic significance of these mutations in myeloproliferative neoplasm disease biology and provided greater insights on the pathways that are dysregulated with each mutation. The models are useful tools that have led to preclinical testing and provided data as validation for future myeloproliferative neoplasm clinical trials.

Addressing and proposing solutions for unmet clinical needs in the management of myeloproliferative neoplasm-associated thrombosis: A consensus-based position paper

This article presents the results of a group discussion among an ad hoc constituted Panel of experts aimed at highlighting unmet clinical needs (UCNs) in the management of thrombotic risk and thrombotic events associated with Philadelphia-negative myeloproliferative neoplasms (Ph-neg MPNs). With the Delphi technique, the challenges in Ph-neg MPN-associated thrombosis were selected. The most clinically relevant UCNs resulted in: (1) providing evidence of the benefits and risks of direct oral anticoagulants, (2) providing evidence of the benefits and risks of cytoreduction in patients with splanchnic vein thrombosis without hypercythemia, (3) improving knowledge of the role of the mutated endothelium in the pathogenesis of thrombosis, (4) improving aspirin dosing regimens in essential thrombocythemia, (5) improving antithrombotic management of Ph-neg MPN-associated pregnancy, (6) providing evidence for the optimal duration of anticoagulation for prophylaxis of recurrent VTE, (7) improving knowledge of the association between somatic gene mutations and risk factors for thrombosis, and (8) improving the grading system of thrombosis risk in polycythemia vera. For each of these issues, proposals for advancement in research and clinical practice were addressed. Hopefully, this comprehensive overview will serve to inform the design and implementation of new studies in the field.

Overview of the Mutational Landscape in Primary Myelofibrosis and Advances in Novel Therapeutics

Primary Myelofibrosis is a BCR-ABL negative myeloproliferative neoplasm with a variety of hematological presentations, including thrombosis, bleeding diathesis and marrow fibrosis. It is estimated to have an incidence of 1.5 per 100,000 people each year. Although JAK2 or MPL mutations are seen in PMF, several other mutations have recently been documented, including mutations in CALR, epigenetic regulators like TET, ASXL1, and 13q deletions. The identification of these mutations has improved the ability to develop novel treatment options. These include JAK inhibitors like ruxolitinib, heat shock protein-90 inhibitors like ganetespib, histone deacetylase inhibitors including panobinostat, pracinostat, vorinostat and givinostat, hypomethylating agents like decitabine, hedgehog inhibitors like glasdegib, PI3K, AKT and mTOR inhibitors like everolimus as well as telomerase inhibitors like imtelstat. Research on novel therapeutic options is being actively pursued in order to expand treatment options for primary myelofibrosis however currently, there is no curative therapy other than allogenic hematopoietic stem cell transplantation (ASCT) which is possible in select patients.

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.

The biology, pathogenesis and clinical aspects of acute lymphoblastic leukemia in children with Down syndrome

Children with Down syndrome (DS) are at a 20-fold increased risk for acute lymphoblastic leukemia (DS-ALL). Although the etiology of this higher risk of developing leukemia remains largely unclear, the recent identification of CRLF2 (cytokine receptor like factor 2) and JAK2 mutations and study of the effect of trisomy of Hmgn1 and Dyrk1a (dual-specificity tyrosine phosphorylation-regulated kinase 1A) on B-cell development have shed significant new light on the disease process. Here we focus on the clinical features, biology and genetics of ALL in children with DS. We review the unique characteristics of DS-ALL on both the clinical and molecular levels and discuss the differences in treatments and outcomes in ALL in children with DS compared with those without DS. The identification of new biological insights is expected to pave the way for novel targeted therapies.

Diagnosis, prevention, and management of bleeding episodes in Philadelphia-negative myeloproliferative neoplasms: recommendations by the Hemostasis Working Party of the German Society of Hematology and Medical Oncology (DGHO) and the Society of Thrombosis and Hemostasis Research (GTH)

Philadelphia-negative myeloproliferative neoplasms (Ph-negative MPN) comprise a heterogeneous group of chronic hematologic malignancies. The quality of life, morbidity, and mortality of patients with MPN are primarily affected by disease-related symptoms, thromboembolic and hemorrhagic complications, and progression to myelofibrosis and acute leukemia. Major bleeding represents a common and important complication in MPN, and the incidence of such bleeding events will become even more relevant in the future due to the increasing disease prevalence and survival of MPN patients. This review discusses the causes, differential diagnoses, prevention, and management of bleeding episodes in patients with MPN, aiming at defining updated standards of care in these often challenging situations.

Genomic landscape of megakaryopoiesis and platelet function defects

Megakaryopoiesis is a complex, stepwise process that takes place largely in the bone marrow. At the apex of the hierarchy, hematopoietic stem cells undergo a number of lineage commitment decisions that ultimately lead to the production of polyploid megakaryocytes. On average, megakaryocytes release 10(11) platelets per day into the blood that repair vascular injuries and prevent excessive bleeding. This differentiation process is tightly controlled by exogenous and endogenous factors, which have been the topics of intense research in the hematopoietic field. Indeed, a skewing of megakaryocyte commitment and differentiation may entail the onset of myeloproliferative neoplasms and other preleukemic disorders together with acute megakaryoblastic leukemia, whereas quantitative or qualitative defects in platelet production can lead to inherited platelet disorders. The recent advent of next-generation sequencing has prompted mapping of the genomic landscape of these conditions to provide an accurate view of the underlying lesions. The aims of this review are to introduce the physiological pathways of megakaryopoiesis and to present landmark studies on acquired and inherited disorders that target them. These studies have not only introduced a new era in the fields of molecular medicine and targeted therapies but may also provide us with a better understanding of the mechanisms underlying normal megakaryopoiesis and thrombopoiesis that can inform efforts to create alternative sources of megakaryocytes and platelets.

Evolving Therapeutic Strategies for the Classic Philadelphia-Negative Myeloproliferative Neoplasms

Despite the emergence of JAK inhibitors, there is a need for disease-modifying treatments for Philadelphia-negative myeloproliferative neoplasms (MPNs). JAK inhibitors ameliorate symptoms and address splenomegaly, but because of the heterogeneous contributors to the disease process, JAK inhibitor monotherapy incompletely addresses the burden of disease. The ever-growing understanding of MPN pathogenesis has provided the rationale for testing novel and targeted therapeutic agents, as monotherapies or in combination, in preclinical and clinical settings. A number of intriguing options have emerged, and it is hoped that further progress will lead to significant changes in the natural history of MPNs.