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Haematologica May 2021Activation of JAK-STAT signaling is one of the hallmarks of myelofibrosis, a myeloproliferative neoplasm that leads to inflammation, progressive bone marrow failure, and... (Review)
Review
Activation of JAK-STAT signaling is one of the hallmarks of myelofibrosis, a myeloproliferative neoplasm that leads to inflammation, progressive bone marrow failure, and a risk of leukemic transformation. Around 90% of patients with myelofibrosis have a mutation in JAK2, MPL, or CALR: so-called 'driver' mutations that lead to activation of JAK2. Ruxolitinib, and other JAK2 inhibitors in clinical use, provide clinical benefit but do not have a major impact on the abnormal hematopoietic clone. This phenomenon is termed 'persistence', in contrast to usual patterns of resistance. Multiple groups have shown that type 1 inhibitors of JAK2, which bind the active conformation of the enzyme, lead to JAK2 becoming resistant to degradation with consequent accumulation of phospho-JAK2. In turn, this can lead to exacerbation of inflammatory manifestations when the JAK inhibitor is discontinued, and it may also contribute to disease persistence. The ways in which JAK2 V617F and CALR mutations lead to activation of JAK-STAT signaling are incompletely understood. We summarize what is known about pathological JAK-STAT activation in myelofibrosis and how this might lead to future novel therapies for myelofibrosis with greater disease-modifying potential.
Topics: Biology; Humans; Janus Kinase 2; Mutation; Myeloproliferative Disorders; Nitriles; Primary Myelofibrosis; Pyrazoles; Pyrimidines
PubMed: 33472356
DOI: 10.3324/haematol.2020.262691 -
Current Hematologic Malignancy Reports Jun 2024Summarize best practices for management of patients with early myelofibrosis (MF). (Review)
Review
PURPOSE OF REVIEW
Summarize best practices for management of patients with early myelofibrosis (MF).
RECENT FINDINGS
Myelofibrosis is a progressive myeloproliferative neoplasm (MPN) that generally produces burdensome symptoms and ultimately leads to worse overall survival than that observed in healthy controls or patients with other MPNs. Several Janus kinase inhibitors and various interferon formulations are now available for treatment of MF, with ruxolitinib notable for extending overall survival in addition to improving MF signs and symptoms. The chronic nature of the disease can lead some patients to avoid immediate treatment in favor of a watch-and-wait approach. This review summarizes the patient management approach taken in my practice, providing guidance and a discussion of best practices with an emphasis on the importance and clinical benefits of active treatment in early MF. In particular, a case is made to consider treatment with ruxolitinib for patients with intermediate-1 risk disease and to minimize delay between diagnosis and treatment initiation for patients with intermediate or high-risk disease.
Topics: Humans; Primary Myelofibrosis; Disease Management; Pyrazoles; Pyrimidines; Nitriles; Janus Kinase Inhibitors; Practice Guidelines as Topic
PubMed: 38441783
DOI: 10.1007/s11899-024-00729-8 -
The Oncologist Oct 2015Primary myelofibrosis is a stem cell-derived clonal malignancy characterized by unchecked proliferation of myeloid cells, resulting in bone marrow fibrosis,... (Review)
Review
Primary myelofibrosis is a stem cell-derived clonal malignancy characterized by unchecked proliferation of myeloid cells, resulting in bone marrow fibrosis, osteosclerosis, and pathologic angiogenesis. Bone marrow fibrosis (BMF) plays a central role in the pathophysiology of the disease. This review describes current issues regarding BMF in primary myelofibrosis, including the pathophysiology and impact of abnormal deposition of excess collagen and reticulin fibers in bone marrow spaces, the modified Bauermeister and the European Consensus grading systems of BMF, and the prognostic impact of BMF on the overall outcome of patients with primary myelofibrosis. The impact of novel therapeutic strategies, including JAK-STAT inhibitors and allogeneic stem cell transplant, on BMF is discussed.
Topics: Bone Marrow Cells; Busulfan; Fibrosis; Humans; Janus Kinases; Nitriles; Primary Myelofibrosis; Prognosis; Pyrazoles; Pyrimidines; STAT Transcription Factors; Stem Cell Transplantation
PubMed: 26304912
DOI: 10.1634/theoncologist.2015-0094 -
Biology of Blood and Marrow... Apr 2018The prognosis of myeloproliferative neoplasms, including primary myelofibrosis (PMF), polycythemia vera, and essential thrombocythemia varies considerably, between these... (Review)
Review
The prognosis of myeloproliferative neoplasms, including primary myelofibrosis (PMF), polycythemia vera, and essential thrombocythemia varies considerably, between these disorders as well as within each diagnosis. Molecular studies have identified "driver mutations" in JAK2, MPL1, and CALR and additional somatic DNA mutations, including ASXL1, EZH2, IDH1/2, and SRSF2, that affect prognosis differentially. Patients with mutations in CALR (type1) have a better outlook than patients with mutations in JAK2 or MPL, whereas patients without any of the driver mutations (triple negative) have the shortest life expectancy. Mutations in ASXL1, EZH2, and SRSF2 may be associated with shortened survival, and IDH mutations carry a higher risk of leukemic transformation. The combination and number of mutations are more important than a given single mutation. Mutations also appear to impact the outcome of hematopoietic cell transplantation (HCT), currently the only treatment with curative potential. Based on available data, the best post-HCT outcome is observed with CALR mutations. Triple negativity has a negative impact. The data on JAK2 are controversial. Mutations in ASXL1 or IDH1/2 reduce the probability of progression-free survival after HCT, although the impact of ASXL1 differs between patients with primary and secondary myelofibrosis. Although it is not clear to what extent HCT can overcome the risks associated with a given mutational pattern, at present, early HCT should be considered in triple-negative patients and patients with PMF who harbor mutations in ASXL1. Mutations in EZH2, SRSF2, or IDH, particularly if combined with other mutations, should also lead to consideration of HCT. Further studies are needed to validate the present observations and determine the impact of additional mutations that have been identified.
Topics: Allografts; Decision Making; Disease-Free Survival; Hematopoietic Stem Cell Transplantation; Humans; Mutation; Neoplasm Proteins; Primary Myelofibrosis; Survival Rate
PubMed: 29128551
DOI: 10.1016/j.bbmt.2017.10.037 -
Frontiers in Immunology 2021Myeloid neoplasms, including acute myeloid leukemia (AML), myeloproliferative neoplasms (MPNs), and myelodysplastic syndromes (MDS), feature clonal dominance and... (Review)
Review
Myeloid neoplasms, including acute myeloid leukemia (AML), myeloproliferative neoplasms (MPNs), and myelodysplastic syndromes (MDS), feature clonal dominance and remodeling of the bone marrow niche in a manner that promotes malignant over non-malignant hematopoiesis. This take-over of hematopoiesis by the malignant clone is hypothesized to include hyperactivation of inflammatory signaling and overproduction of inflammatory cytokines. In the -negative MPNs, inflammatory cytokines are considered to be responsible for a highly deleterious pathophysiologic process: the phenotypic transformation of polycythemia vera (PV) or essential thrombocythemia (ET) to secondary myelofibrosis (MF), and the equivalent emergence of primary myelofibrosis (PMF). Bone marrow fibrosis itself is thought to be mediated heavily by the cytokine TGF-β, and possibly other cytokines produced as a result of hyperactivated JAK2 kinase in the malignant clone. MF also features extramedullary hematopoiesis and progression to bone marrow failure, both of which may be mediated in part by responses to cytokines. In MF, elevated levels of individual cytokines in plasma are adverse prognostic indicators: elevated IL-8/CXCL8, in particular, predicts risk of transformation of MF to secondary AML (sAML). Tumor necrosis factor (TNF, also known as TNFα), may underlie malignant clonal dominance, based on results from mouse models. Human PV and ET, as well as MF, harbor overproduction of multiple cytokines, above what is observed in normal aging, which can lead to cellular signaling abnormalities separate from those directly mediated by hyperactivated JAK2 or MPL kinases. Evidence that NFκB pathway signaling is frequently hyperactivated in a pan-hematopoietic pattern in MPNs, including in cells outside the malignant clone, emphasizes that MPNs are pan-hematopoietic diseases, which remodel the bone marrow milieu to favor persistence of the malignancy. Clinical evidence that JAK2 inhibition by ruxolitinib in MF neither reliably reduces malignant clonal burden nor eliminates cytokine elevations, suggests targeting cytokine mediated signaling as a therapeutic strategy, which is being pursued in new clinical trials. Greater knowledge of inflammatory pathophysiology in MPNs can therefore contribute to the development of more effective therapy.
Topics: Age Factors; Biomarkers; Cell Transformation, Neoplastic; Cytokines; Disease Susceptibility; Humans; Inflammation Mediators; Models, Biological; Myeloproliferative Disorders; Primary Myelofibrosis; Signal Transduction
PubMed: 34140953
DOI: 10.3389/fimmu.2021.683401 -
Turkish Journal of Haematology :... Feb 2020
Topics: Aged, 80 and over; Antineoplastic Agents; Humans; Hydroxyurea; Male; Primary Myelofibrosis; Tooth Discoloration
PubMed: 31711282
DOI: 10.4274/tjh.galenos.2019.2019.0275 -
Haematologica Sep 2020
Topics: Humans; Interferons; Nitriles; Pharmaceutical Preparations; Polycythemia Vera; Primary Myelofibrosis; Pyrazoles; Pyrimidines
PubMed: 33054041
DOI: 10.3324/haematol.2020.256602 -
Haematologica Jun 2016Bone marrow fibrosis is a central pathological feature and World Health Organization major diagnostic criterion of myelofibrosis. Although bone marrow fibrosis is seen... (Review)
Review
Bone marrow fibrosis is a central pathological feature and World Health Organization major diagnostic criterion of myelofibrosis. Although bone marrow fibrosis is seen in a variety of malignant and non-malignant disease states, the deposition of reticulin and collagen fibrosis in the bone marrow of patients with myelofibrosis is believed to be mediated by the myelofibrosis hematopoietic stem/progenitor cell, contributing to an impaired microenvironment favoring malignant over normal hematopoiesis. Increased expression of inflammatory cytokines, lysyl oxidase, transforming growth factor-β, impaired megakaryocyte function, and aberrant JAK-STAT signaling have all been implicated in the pathogenesis of bone marrow fibrosis. A number of studies indicate that bone marrow fibrosis is an adverse prognostic variable in myeloproliferative neoplasms. However, modern myelofibrosis prognostication systems utilized in risk-adapted treatment approaches do not include bone marrow fibrosis as a prognostic variable. The specific effect on bone marrow fibrosis of JAK2 inhibition, and other rationally based therapies currently being evaluated in myelofibrosis, has yet to be fully elucidated. Hematopoietic stem cell transplantation remains the only curative therapeutic approach that reliably results in resolution of bone marrow fibrosis in patients with myelofibrosis. Here we review the pathogenesis, biological consequences, and prognostic impact of bone marrow fibrosis. We discuss the rationale of various anti-fibrogenic treatment strategies targeting the clonal hematopoietic stem/progenitor cell, aberrant signaling pathways, fibrogenic cytokines, and the tumor microenvironment.
Topics: Animals; Bone Marrow; Bone Marrow Cells; Cell Transformation, Neoplastic; Cellular Microenvironment; Disease Progression; Genetic Predisposition to Disease; Humans; Molecular Targeted Therapy; Primary Myelofibrosis; Prognosis; Severity of Illness Index
PubMed: 27252511
DOI: 10.3324/haematol.2015.141283 -
British Journal of Haematology Nov 2019Ruxolitinib has proved to be effective for the treatment of patients with myelofibrosis (either primary or secondary) and polycythaemia vera, and its approval led to a... (Review)
Review
Ruxolitinib has proved to be effective for the treatment of patients with myelofibrosis (either primary or secondary) and polycythaemia vera, and its approval led to a significant change in the current treatment algorithm. Despite its efficacy and beyond its well described haematological toxicity, a peculiar immunosuppressive effect emerged as our clinical experience grew, both within and outside of a clinical trial setting. Definite and negative interactions with multiple pathways of the immune system of patients have been reported so far, involving both adaptive and innate immune responses. These pathophysiological mechanisms may contribute to the increased risk of reactivation of silent infections (e.g., tuberculosis, hepatitis B virus and varicella zoster virus) that have been associated with the drug. Even though such infectious events may be fatal or may lead to significant impairment of organ function, compromising the eligibility of patients for an allotransplant procedure, there are no dedicated guidelines that may help us in assessing and managing the risk of developing serious infections. On this basis, our aim for the present work was to review the current knowledge on the pathophysiological mechanisms through which ruxolitinib may exert its immunosuppressive effect, and to illustrate our personal approach to the management of three peculiar clinical scenarios, for which a risk-based algorithm is suggested.
Topics: Adaptive Immunity; Humans; Immune Tolerance; Immunity, Innate; Infections; Nitriles; Polycythemia Vera; Practice Guidelines as Topic; Primary Myelofibrosis; Pyrazoles; Pyrimidines
PubMed: 31468506
DOI: 10.1111/bjh.16174 -
Blood Advances Dec 2023JAK2 V617F is the most common driver mutation in primary or secondary myelofibrosis for which allogeneic hematopoietic cell transplantation (HCT) is the only curative...
JAK2 V617F is the most common driver mutation in primary or secondary myelofibrosis for which allogeneic hematopoietic cell transplantation (HCT) is the only curative treatment. Knowledge of the prognostic utility of JAK2 alterations in the HCT setting is limited. We identified all patients with MF who received HCT between 2000 and 2016 and had a pre-HCT blood sample (N = 973) available at the Center of International Blood and Marrow Transplant Research biorepository. PacBio sequencing and single nucleotide polymorphism-array genotyping were used to identify JAK2V617F mutation and associated mosaic chromosomal alterations (mCAs), respectively. Cox proportional hazard models were used for HCT outcome analyses. Genomic testing was complete for 924 patients with MF (634 primary MF [PMF], 135 postpolycythemia vera [PPV-MF], and 155 postessential thrombocytopenia [PET-MF]). JAK2V617F affected 562 patients (57.6% of PMF, 97% of PPV-MF, and 42.6% of PET-MF). Almost all patients with mCAs involving the JAK2 region (97.9%) were JAK2V617-positive. In PMF, JAK2V617F mutation status, allele burden, or identified mCAs were not associated with disease progression/relapse, nonrelapse mortality (NRM), or overall survival. Almost all PPV-MF were JAK2V617F-positive (97%), with no association between HCT outcomes and mutation allele burden or mCAs. In PET-MF, JAK2V617F high mutation allele burden (≥60%) was associated with excess risk of NRM, restricted to transplants received in the era of JAK inhibitors (2013-2016; hazard ratio = 7.65; 95% confidence interval = 2.10-27.82; P = .002). However, allele burden was not associated with post-HCT disease progression/relapse or survival. Our findings support the concept that HCT can mitigate the known negative effect of JAK2V617F in patients with MF, particularly for PMF and PPV-MF.
Topics: Humans; Primary Myelofibrosis; Prognosis; Mutation; Disease Progression; Chromosome Aberrations; Recurrence; Janus Kinase 2
PubMed: 38011490
DOI: 10.1182/bloodadvances.2023010882