-
American Journal of Hematology Jan 2021Primary myelofibrosis (PMF) is a myeloproliferative neoplasm (MPN) characterized by stem cell-derived clonal myeloproliferation that is often but not always accompanied... (Review)
Review
DISEASE OVERVIEW
Primary myelofibrosis (PMF) is a myeloproliferative neoplasm (MPN) characterized by stem cell-derived clonal myeloproliferation that is often but not always accompanied by JAK2, CALR, or MPL mutations. Additional disease features include bone marrow reticulin/collagen fibrosis, aberrant inflammatory cytokine expression, anemia, hepatosplenomegaly, extramedullary hematopoiesis (EMH), constitutional symptoms, cachexia, leukemic progression, and shortened survival.
DIAGNOSIS
Bone marrow morphology is the primary basis for diagnosis. Presence of JAK2, CALR, or MPL mutation, expected in around 90% of the patients, is supportive but not essential for diagnosis; these mutations are also prevalent in the closely related MPNs, namely polycythemia vera (PV) and essential thrombocythemia (ET). The 2016 World Health Organization classification system distinguishes "prefibrotic" from "overtly fibrotic" PMF; the former might mimic ET in its presentation. Furthermore, approximately 15% of patients with ET or PV might progress into a PMF-like phenotype (post-ET/PV MF) during their clinical course.
ADVERSE MUTATIONS
SRSF2, ASXL1, and U2AF1-Q157 mutations predict inferior survival in PMF, independent of each other and other risk factors. RAS/CBL mutations predicted resistance to ruxolitinib therapy.
ADVERSE KARYOTYPE
Very high risk abnormalities include -7, inv (3), i(17q), +21, +19, 12p-, and 11q-.
RISK STRATIFICATION
Two new prognostic systems for PMF have recently been introduced: GIPSS (genetically-inspired prognostic scoring system) and MIPSS70+ version 2.0 (MIPSSv2; mutation- and karyotype-enhanced international prognostic scoring system). GIPSS is based exclusively on mutations and karyotype. MIPSSv2 includes, in addition, clinical risk factors. GIPSS features four and MIPSSv2 five risk categories.
RISK-ADAPTED THERAPY
Observation alone is advised for MIPSSv2 "low" and "very low" risk disease (estimated 10-year survival 56%-92%); allogeneic hematopoietic stem cell transplant (AHSCT) is the preferred treatment for "very high" and "high" risk disease (estimated 10-year survival 0%-13%); treatment-requiring patients with intermediate-risk disease (estimated 10-year survival 30%) are best served by participating in clinical trials. In non-transplant candidates, conventional treatment for anemia includes androgens, prednisone, thalidomide, and danazol; for symptomatic splenomegaly, hydroxyurea and ruxolitinib; and for constitutional symptoms, ruxolitinib. Fedratinib, another JAK2 inhibitor, has now been FDA-approved for use in ruxolitinib failures. Splenectomy is considered for drug-refractory splenomegaly and involved field radiotherapy for non-hepatosplenic EMH and extremity bone pain.
NEW DIRECTIONS
A number of new agents, alone or in combination with ruxolitinib, are currently under investigation for MF treatment (ClinicalTrials.gov); preliminary results from some of these clinical trials were presented at the 2020 ASH annual meeting and highlighted in the current document.
Topics: Disease-Free Survival; Humans; Mutation; Primary Myelofibrosis; Risk Assessment; Survival Rate
PubMed: 33197049
DOI: 10.1002/ajh.26050 -
American Journal of Hematology May 2023Primary myelofibrosis (PMF) is a myeloproliferative neoplasm (MPN) characterized by stem cell-derived clonal myeloproliferation that is often but not always accompanied... (Review)
Review
DISEASE OVERVIEW
Primary myelofibrosis (PMF) is a myeloproliferative neoplasm (MPN) characterized by stem cell-derived clonal myeloproliferation that is often but not always accompanied by JAK2, CALR, or MPL mutations; additional features include bone marrow reticulin/collagen fibrosis, aberrant inflammatory cytokine expression, anemia, hepatosplenomegaly, extramedullary hematopoiesis (EMH), constitutional symptoms, cachexia, risk of leukemic progression, and shortened survival.
DIAGNOSIS
Bone marrow examination with cytogenetic and mutation studies provides integrated diagnostic information; presence of JAK2, CALR or MPL mutation is expected but not required.
NEW CLASSIFICATION SYSTEM
The International Consensus Classification distinguishes "prefibrotic" from "overtly fibrotic" PMF; the former might mimic essential thrombocythemia (ET) in its presentation. Approximately 15% of patients with ET or polycythemia vera (PV) might progress into post-ET/PV MF.
MUTATIONS
SRSF2, ASXL1, and U2AF1-Q157 mutations predict inferior survival in PMF; RAS/CBL mutations predict resistance to ruxolitinib therapy. Type 1/like CALR mutation is associated with superior survival.
KARYOTYPE
Very high-risk abnormalities include -7, inv (3), i(17q), +21, +19, 12p- and 11q-. Favorable risk abnormalities include normal karyotype or isolated +9, 13q-, 20q-, 1q abnormalities and loss of Y chromosome.
RISK STRATIFICATION
Contemporary prognostic systems include GIPSS (genetically-inspired prognostic scoring system) and MIPSS70+ version 2.0 (MIPSSv2; mutation-and karyotype-enhanced international prognostic scoring system). GIPSS is based exclusively on mutations and karyotype; MIPSSv2 includes, in addition, clinical risk factors.
RISK-ADAPTED THERAPY
Observation alone is advised for MIPSSv2 "low" and "very low" risk disease (estimated 10-year survival 56%-92%); allogeneic hematopoietic stem cell transplant (AHSCT) is the preferred treatment of choice for "very high" and "high" risk disease (estimated 10-year survival 0-13%), as well as in carefully selected patients with intermediate-risk disease (estimated 10-year survival 30%). Drug therapy in MF is currently palliative and targets anemia, splenomegaly, and constitutional symptoms. JAK2 INHIBITORS: Ruxolitinib, fedratinib, and pacritinib are FDA approved and respectfully utilized in patients failing treatment with hydroxyurea, ruxolitinib, or with platelet count <50 × 10 (9)/L. Momelotinib is another JAK2 inhibitor that is poised for approval sometime in 2023 and has shown erythropoietic benefits, in addition to affecting spleen and symptom responses.
OTHER TREATMENT MODALITIES
Splenectomy is considered for drug-refractory splenomegaly and involved field radiotherapy for non-hepatosplenic EMH and extremity bone pain.
NEW DIRECTIONS
New agents, alone or in combination with ruxolitinib, are currently under clinical trial investigation (ClinicalTrials.gov) and preliminary results were presented at the 2022 ASH annual meeting and highlighted in the current review.
Topics: Humans; Primary Myelofibrosis; Splenomegaly; Polycythemia Vera; Pyrazoles; Thrombocythemia, Essential; Mutation; Janus Kinase 2
PubMed: 36680511
DOI: 10.1002/ajh.26857 -
Blood Apr 2023The clinical phenotype of primary and post-polycythemia vera and postessential thrombocythemia myelofibrosis (MF) is dominated by splenomegaly, symptomatology, a variety... (Review)
Review
The clinical phenotype of primary and post-polycythemia vera and postessential thrombocythemia myelofibrosis (MF) is dominated by splenomegaly, symptomatology, a variety of blood cell alterations, and a tendency to develop vascular complications and blast phase. Diagnosis requires assessing complete cell blood counts, bone marrow morphology, deep genetic evaluations, and disease history. Driver molecular events consist of JAK2V617F, CALR, and MPL mutations, whereas about 8% to 10% of MF are "triple-negative." Additional myeloid-gene variants are described in roughly 80% of patients. Currently available clinical-based and integrated clinical/molecular-based scoring systems predict the survival of patients with MF and are applied for conventional treatment decision-making, indication to stem cell transplant (SCT) and allocation in clinical trials. Standard treatment consists of anemia-oriented therapies, hydroxyurea, and JAK inhibitors such as ruxolitinib, fedratinib, and pacritinib. Overall, spleen volume reduction of 35% or greater at week 24 can be achieved by 42% of ruxolitinib-, 47% of fedratinib-, 19% of pacritinib-, and 27% of momelotinib-treated patients. Now, it is time to move towards new paradigms for evaluating efficacy like disease modification, that we intend as a robust and unequivocal effect on disease biology and/or on patient survival. The growing number of clinical trials potentially pave the way for new strategies in patients with MF. Translational studies of some molecules showed an early effect on bone marrow fibrosis and on variant allele frequencies of myeloid genes. SCT is still the only curative option, however, it is associated with relevant challenges. This review focuses on the diagnosis, prognostication, and treatment of MF.
Topics: Humans; Primary Myelofibrosis; Pyrazoles; Nitriles; Janus Kinase 2
PubMed: 36416738
DOI: 10.1182/blood.2022017423 -
Blood Apr 2023BCR::ABL1-negative myeloproliferative neoplasms (MPNs) are clonal diseases originating from a single hematopoietic stem cell that cause excessive production of mature... (Review)
Review
BCR::ABL1-negative myeloproliferative neoplasms (MPNs) are clonal diseases originating from a single hematopoietic stem cell that cause excessive production of mature blood cells. The 3 subtypes, that is, polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF), are diagnosed according to the World Health Organization (WHO) and international consensus classification (ICC) criteria. Acquired gain-of-function mutations in 1 of 3 disease driver genes (JAK2, CALR, and MPL) are the causative events that can alone initiate and promote MPN disease without requiring additional cooperating mutations. JAK2-p.V617F is present in >95% of PV patients, and also in about half of the patients with ET or PMF. ET and PMF are also caused by mutations in CALR or MPL. In ∼10% of MPN patients, those referred to as being "triple negative," none of the known driver gene mutations can be detected. The common theme between the 3 driver gene mutations and triple-negative MPN is that the Janus kinase-signal transducer and activator of transcription (JAK/STAT) signaling pathway is constitutively activated. We review the recent advances in our understanding of the early events after the acquisition of a driver gene mutation. The limiting factor that determines the frequency at which MPN disease develops with a long latency is not the acquisition of driver gene mutations, but rather the expansion of the clone. Factors that control the conversion from clonal hematopoiesis to MPN disease include inherited predisposition, presence of additional mutations, and inflammation. The full extent of knowledge of the mutational landscape in individual MPN patients is now increasingly being used to predict outcome and chose the optimal therapy.
Topics: Humans; Primary Myelofibrosis; Calreticulin; Receptors, Thrombopoietin; Myeloproliferative Disorders; Polycythemia Vera; Thrombocythemia, Essential; Janus Kinase 2; Mutation
PubMed: 36347013
DOI: 10.1182/blood.2022017578 -
British Journal of Haematology Oct 2020Myelofibrosis is an enigmatic myeloproliferative neoplasm, despite noteworthy strides in understanding its genetic underpinnings. Driver mutations involving JAK2, CALR... (Review)
Review
Myelofibrosis is an enigmatic myeloproliferative neoplasm, despite noteworthy strides in understanding its genetic underpinnings. Driver mutations involving JAK2, CALR or MPL in 90% of patients mediate constitutive JAK-STAT signaling which, in concert with epigenetic alterations (ASXL1, DNMT3A, SRSF2, EZH2, IDH1/2 mutations), play a fundamental role in disease pathogenesis. Aberrant immature megakaryocytes are a quintessential feature, exhibiting reduced GATA1 protein expression and secreting a plethora of pro-inflammatory cytokines (IL-1 ß, TGF-ß), growth factors (b-FGF, PDGF, VEGF) in addition to extra cellular matrix components (fibronectin, laminin, collagens). The ensuing disrupted interactions amongst the megakaryocytes, osteoblasts, endothelium, stromal cells and myofibroblasts within the bone marrow culminate in the development of fibrosis and osteosclerosis. Presently, prognostic assessment tools for primary myelofibrosis (PMF) are centered on genetics, with incorporation of cytogenetic and molecular information into the mutation-enhanced (MIPSS 70-plus version 2.0) and genetically-inspired (GIPSS) prognostic scoring systems. Both models illustrate substantial clinical heterogeneity in PMF and serve as the crux for risk-adapted therapeutic decisions. A major challenge remains the dearth of disease-modifying drugs, whereas allogeneic transplant offers the chance of long-term remission for some patients. Our review serves to synopsise current appreciation of the pathogenesis of myelofibrosis together with emerging management strategies.
Topics: Gene Expression Regulation; Humans; Mutation; Myofibroblasts; Primary Myelofibrosis
PubMed: 32196650
DOI: 10.1111/bjh.16576 -
Future Oncology (London, England) Jun 2022Myelofibrosis is a myeloproliferative neoplasm characterized by splenomegaly, debilitating constitutional symptoms and bone marrow failure. Disease-related anemia is... (Review)
Review
Myelofibrosis is a myeloproliferative neoplasm characterized by splenomegaly, debilitating constitutional symptoms and bone marrow failure. Disease-related anemia is common and associated with an inferior quality of life and survival. Unfortunately, few therapies exist to improve hemoglobin in myelofibrosis patients. Momelotinib is a JAK1/JAK2 inhibitor that also antagonizes ACVR1, leading to downregulation of hepcidin expression and increased availability of iron for erythropoiesis. In clinical testing, momelotinib has demonstrated a unique ability to improve hemoglobin and reduce transfusion burden in myelofibrosis patients with baseline anemia, while producing reductions in spleen size and symptom burden. This review explores the preclinical rationale, clinical trial data and future role of momelotinib in the evolving therapeutic landscape of myelofibrosis.
Topics: Anemia; Benzamides; Humans; Janus Kinase 2; Janus Kinase Inhibitors; Nitriles; Primary Myelofibrosis; Protein Kinase Inhibitors; Pyrimidines; Quality of Life
PubMed: 35603634
DOI: 10.2217/fon-2022-0276 -
Critical Reviews in Oncology/hematology Dec 2022Myelofibrosis (MF) is a clonal hematologic malignancy with progressive bone marrow fibrosis. Clinical manifestations of MF include splenomegaly, constitutional symptoms,... (Review)
Review
Myelofibrosis (MF) is a clonal hematologic malignancy with progressive bone marrow fibrosis. Clinical manifestations of MF include splenomegaly, constitutional symptoms, and anemia, whose pathogenesis is multifactorial and largely due to ineffective erythropoiesis and is clinically associated with poor quality of life and reduced overall survival. The only curative treatment for MF is allogenic stem cell transplantation; however, few patients are eligible. Disease management strategies for MF-related anemia have limited effectiveness, and Janus kinase (JAK) inhibitors may induce or worsen related anemia. Thus, there is a significant unmet need for the treatment of patients with MF-related anemia. This review summarizes current and emerging treatments for anemia in MF, including luspatercept and KER-050 (transforming growth factor-β ligand traps), momelotinib and pacritinib (JAK inhibitors), pelabresib (a bromodomain extra-terminal domain inhibitor), PRM-151 (an antifibrotic agent), imetelstat (a telomerase inhibitor), and navitoclax (a BCL-2/BCL-xL inhibitor). Therapeutic combinations with ruxolitinib may offer another treatment approach.
Topics: Humans; Primary Myelofibrosis; Janus Kinase 2; Quality of Life; Nitriles; Anemia; Antineoplastic Agents; Protein Kinase Inhibitors
PubMed: 36332787
DOI: 10.1016/j.critrevonc.2022.103862 -
Cells Dec 2021Classical BCR-ABL-negative myeloproliferative neoplasms (MPN) are a heterogeneous group of hematologic malignancies, including essential thrombocythemia (ET),... (Review)
Review
Classical BCR-ABL-negative myeloproliferative neoplasms (MPN) are a heterogeneous group of hematologic malignancies, including essential thrombocythemia (ET), polycythemia vera (PV), and primary myelofibrosis (PMF), as well as post-PV-MF and post-ET-MF. Progression to more symptomatic disease, such as overt MF or acute leukemia, represents one of the major causes of morbidity and mortality. There are clinically evident but also subclinical types of MPN progression. Clinically evident progression includes evolution from ET to PV, ET to post-ET-MF, PV to post-PV-MF, or pre-PMF to overt PMF, and transformation of any of these subtypes to myelodysplastic neoplasms or acute leukemia. Thrombosis, major hemorrhage, severe infections, or increasing symptom burden (e.g., pruritus, night sweats) may herald progression. Subclinical types of progression may include increases in the extent of bone marrow fibrosis, increases of driver gene mutational allele burden, and clonal evolution. The underlying causes of MPN progression are diverse and can be attributed to genetic alterations and chronic inflammation. Particularly, bystander mutations in genes encoding epigenetic regulators or splicing factors were associated with progression. Finally, comorbidities such as systemic inflammation, cardiovascular diseases, and organ fibrosis may augment the risk of progression. The aim of this review was to discuss types and mechanisms of MPN progression and how their knowledge might improve risk stratification and therapeutic intervention. In view of these aspects, we discuss the potential benefits of early diagnosis using molecular and functional imaging and exploitable therapeutic strategies that may prevent progression, but also highlight current challenges and methodological pitfalls.
Topics: Disease Progression; Fusion Proteins, bcr-abl; Humans; Leukemia; Mutation; Myelodysplastic Syndromes; Myeloproliferative Disorders; Polycythemia Vera; Primary Myelofibrosis; Thrombocythemia, Essential; Thrombosis
PubMed: 34944059
DOI: 10.3390/cells10123551 -
Cells Apr 2021Myelofibrosis is a myeloproliferative neoplasm characterized by splenomegaly, constitutional symptoms, bone marrow fibrosis, and a propensity towards transformation to... (Review)
Review
Myelofibrosis is a myeloproliferative neoplasm characterized by splenomegaly, constitutional symptoms, bone marrow fibrosis, and a propensity towards transformation to acute leukemia. JAK inhibitors are the only approved therapy for myelofibrosis and have been successful in reducing spleen and symptom burden. However, they do not significantly impact disease progression and many patients are ineligible due to coexisting cytopenias. Patients who are refractory to JAK inhibition also have a dismal survival. Therefore, non-JAK inhibitor-based therapies are being explored in pre-clinical and clinical settings. In this review, we discuss novel treatments in development for myelofibrosis with targets outside of the JAK-STAT pathway. We focus on the mechanism, preclinical rationale, and available clinical efficacy and safety information of relevant agents including those that target apoptosis (navitoclax, KRT-232, LCL-161, imetelstat), epigenetic modulation (CPI-0610, bomedemstat), the bone marrow microenvironment (PRM-151, AVID-200, alisertib), signal transduction pathways (parsaclisib), and miscellaneous agents (tagraxofusp. luspatercept). We also provide commentary on the future of therapeutic development in myelofibrosis.
Topics: Apoptosis; Epigenesis, Genetic; Humans; Janus Kinases; Primary Myelofibrosis; Protein Kinase Inhibitors; Signal Transduction
PubMed: 33925695
DOI: 10.3390/cells10051034 -
Annals of Hematology Jun 2020Myelofibrosis is a BCR-ABL1-negative myeloproliferative neoplasm characterized by anemia, progressive splenomegaly, extramedullary hematopoiesis, bone marrow fibrosis,... (Review)
Review
Myelofibrosis is a BCR-ABL1-negative myeloproliferative neoplasm characterized by anemia, progressive splenomegaly, extramedullary hematopoiesis, bone marrow fibrosis, constitutional symptoms, leukemic progression, and shortened survival. Constitutive activation of the Janus kinase/signal transducers and activators of transcription (JAK-STAT) pathway, and other cellular pathways downstream, leads to myeloproliferation, proinflammatory cytokine expression, and bone marrow remodeling. Transplant is the only curative option for myelofibrosis, but high rates of morbidity and mortality limit eligibility. Several prognostic models have been developed to facilitate treatment decisions. Until the recent approval of fedratinib, a JAK2 inhibitor, ruxolitinib was the only available JAK inhibitor for treatment of intermediate- or high-risk myelofibrosis. Ruxolitinib reduces splenomegaly to some degree in almost all treated patients; however, many patients cannot tolerate ruxolitinib due to dose-dependent drug-related cytopenias, and even patients with a good initial response often develop resistance to ruxolitinib after 2-3 years of therapy. Currently, there is no consensus definition of ruxolitinib failure. Until fedratinib approval, strategies to overcome ruxolitinib resistance or intolerance were mainly different approaches to continued ruxolitinib therapy, including dosing modifications and ruxolitinib rechallenge. Fedratinib and two other JAK2 inhibitors in later stages of clinical development, pacritinib and momelotinib, have been shown to induce clinical responses and improve symptoms in patients previously treated with ruxolitinib. Fedratinib induces robust spleen responses, and pacritinib and momelotinib may have preferential activity in patients with severe cytopenias. Reviewed here are strategies to ameliorate ruxolitinib resistance or intolerance, and outcomes of clinical trials in patients with myelofibrosis receiving second-line JAK inhibitors after ruxolitinib treatment.
Topics: Clinical Trials as Topic; Disease Management; Humans; Janus Kinases; Nitriles; Primary Myelofibrosis; Pyrazoles; Pyrimidines; Pyrrolidines; Sulfonamides; Treatment Failure
PubMed: 32198525
DOI: 10.1007/s00277-020-04002-9