Myeloproliferative neoplasm (MPN)-associated myelofibrosis (MF) is characterized by cytopenias, marrow fibrosis, constitutional symptoms, extramedullary hematopoiesis, splenomegaly, and shortened ...survival. Constitutive activation of the janus kinase/signal transducer and activator of transcription (JAK/STAT) signaling pathway in MF leads to cell proliferation, inhibition of cell death, and clonal expansion of myeloproliferative malignant cells. Fedratinib is a selective oral JAK2 inhibitor recently approved in the United States for treatment of adult patients with intermediate-2 or high-risk MF. In mouse models of JAK2V617F-driven myeloproliferative disease, fedratinib blocked phosphorylation of STAT5, increased survival, and improved MF-associated disease features, including reduction of white blood cell counts, hematocrit, splenomegaly, and fibrosis. Fedratinib exerts off-target inhibitory activity against bromodomain-containing protein 4 (BRD4); combination JAK/STAT and BRD4 inhibition was shown to synergistically block NF-kB hyperactivation and inflammatory cytokine production, attenuating disease burden and reversing bone marrow fibrosis in animal models of MPNs. In patients, fedratinib is rapidly absorbed and dosed once daily (effective half-life 41 h). Fedratinib showed robust clinical activity in JAK-inhibitor-naïve patients and in patients with MF who were relapsed, refractory, or intolerant to prior ruxolitinib therapy. Fedratinib is effective regardless of JAK2 mutation status. Onset of spleen and symptom responses are typically seen within the first 1-2 months of treatment. The most common adverse events (AEs) with fedratinib are grades 1-2 gastrointestinal events, which are most frequent during early treatment and decrease over time. Treatment discontinuation due to hematologic AEs in clinical trials was uncommon (~3%). Suspected cases of Wernicke's encephalopathy were reported during fedratinib trials in ~1% of patients; thiamine levels should be monitored before and during fedratinib treatment as medically indicated. Phase III trials are ongoing to assess fedratinib effects on long-term safety, efficacy, and overall survival. The recent approval of fedratinib provides a much-needed addition to the limited therapeutic options available for patients with MF.
Myeloproliferative neoplasms (MPNs) are the most common etiologies of primary splanchnic vein thrombosis, present in almost forty percent of patients with Budd-Chiari syndrome or portal vein ...thrombosis. Diagnosis of MPNs can be difficult in these patients because key characteristics, such as elevated blood cell counts and splenomegaly, are confounded by portal hypertension or bleeding complications. In recent years, diagnostic tools have improved to provide more accurate diagnosis and classification of MPNs. Although bone marrow biopsy findings remain a major diagnostic criterion, molecular markers are playing an increasing role not only in diagnosis but also in better estimating prognosis. Therefore, though screening for JAK2V617F mutation should be the starting point of the diagnostic workup performed in all patients with splanchnic vein thrombosis, a multidisciplinary approach is needed to accurately diagnose the subtype of myeloproliferative neoplasm, recommend the useful additional tests (bone marrow biopsy, search for an additional mutation using targeted next-generation sequencing), and suggest the best treatment strategy. Indeed, providing a specific expert care pathway for patients with splanchnic vein thrombosis and underlying myeloproliferative neoplasm is crucial to determine the optimal management to reduce the risk of both hematological and hepatic complications.
Thromboembolic events in polycythemia vera Griesshammer, Martin; Kiladjian, Jean-Jacques; Besses, Carlos
Annals of hematology,
05/2019, Letnik:
98, Številka:
5
Journal Article
Recenzirano
Odprti dostop
Thromboembolic events and cardiovascular disease are the most prevalent complications in patients with polycythemia vera (PV) compared with other myeloproliferative disorders and are the major cause ...of morbidity and mortality in this population. Moreover, a vascular complication such as arterial or venous thrombosis often leads to the diagnosis of PV. The highest rates of thrombosis typically occur shortly before or at diagnosis and decrease over time, probably due to the effects of treatment. Important risk factors include age (≥ 60 years old) and a history of thrombosis; elevated hematocrit and leukocytosis are also associated with an increased risk of thrombosis. The goal of therapy is to reduce the risk of thrombosis by controlling hematocrit to < 45%, a target associated with reduced rates of cardiovascular death and major thrombosis. Low-risk patients (< 60 years old with no history of thrombosis) are managed with phlebotomy and low-dose aspirin, whereas high-risk patients (≥ 60 years old and/or with a history of thrombosis) should be treated with cytoreductive agents. Interferon and ruxolitinib are considered second-line therapies for patients who are intolerant of or have an inadequate response to hydroxyurea, which is typically used as first-line therapy. In this review, we discuss factors associated with thrombosis and recent data on current treatments, including anticoagulation, highlighting the need for more controlled studies to determine the most effective cytoreductive therapies for reducing the risk of thrombosis in patients with PV.
Fedratinib is an oral, selective Janus kinase 2 (JAK2) inhibitor. The phase II JAKARTA2 study assessed fedratinib in patients with intermediate‐ or high‐risk myelofibrosis (MF) who were resistant or ...intolerant to prior ruxolitinib per investigator assessment. Patients received fedratinib 400 mg/day in 28‐day cycles. The JAKARTA2 outcomes were initially reported using a last‐observation‐carried forward (LOCF) analysis in a “Per Protocol” population. This updated analysis of JAKARTA2 employs intention‐to‐treat analysis principles without LOCF for all treated patients (ITT Population; N = 97), and for a patient subgroup who met more stringent definitions of prior ruxolitinib failure (Stringent Criteria Cohort; n = 79). Median duration of prior ruxolitinib exposure was 10.7 months. The primary endpoint was spleen volume response rate (SVRR; ≥35% spleen volume decrease from baseline to end of cycle 6 EOC6). The SVRR was 31% in the ITT Population and 30% in the Stringent Criteria Cohort. Median duration of spleen volume response was not reached. Symptom response rate (≥50% reduction from baseline to EOC6 in total symptom score TSS on the modified Myelofibrosis Symptom Assessment Form MFSAF) was 27%. Grade 3‐4 anemia and thrombocytopenia rates were 38% and 22%, respectively. Patients with advanced MF substantially pretreated with ruxolitinib attained robust spleen responses and reduced symptom burden with fedratinib.
The current standard‐of‐care for treatment of myelofibrosis (MF) comprises inhibitors of the Janus kinase (JAK)/signal transducers and activators (STAT) pathway; however, despite their ability to ...alleviate symptoms, they do not appear to modify underlying disease and have not demonstrated substantial survival benefit. Allogeneic‐hematopoietic stem cell transplantation remains the only curative option for patients with MF but is limited to a subset of high‐risk and fit patients. Early disease modification could positively affect disease trajectory for lower risk patients with MF as well as those with conditions that can precede MF, such as polycythemia vera and essential thrombocythemia. Here, the authors discuss critical unmet needs in the MF treatment paradigm, including: the need for safe, impactful therapies for lower risk patients, thus allowing intervention when success is most likely; better development of first‐line therapies (likely highly novel or combination strategies) for intermediate‐risk/higher risk patients; and approved drugs to manage cytopenia. Finally, a consensus definition of disease modification is needed that informs trial design, allowing the development of clinical end points that enable understanding of therapies and responses and that facilitate the development of therapies that work according to this definition. Through close collaboration between clinicians, patients, and the pharmaceutical industry, better efforts to define benefit and identify patients most likely to benefit from a particular combination or treatment strategy should enable the development of more effective and safe treatments to extend and improve quality of life for patients with MF.
Early disease modification could positively affect the disease trajectory for patients with myelofibrosis. Herein, the authors discuss critical unmet needs in the myelofibrosis treatment paradigm, including safe therapies for lower risk patients, better development of first‐line therapies for intermediate‐risk/higher risk patients, approved drugs to manage cytopenia, and a consensus definition of disease modification.
This document updates the recommendations on the management of Philadelphia chromosome-negative myeloproliferative neoplasms (Ph-neg MPNs) published in 2011 by the European LeukemiaNet (ELN) ...consortium. Recommendations were produced by multiple-step formalized procedures of group discussion. A critical appraisal of evidence by using Grades of Recommendation, Assessment, Development and Evaluation (GRADE) methodology was performed in the areas where at least one randomized clinical trial was published. Seven randomized controlled trials provided the evidence base; earlier phase trials also informed recommendation development. Key differences from the 2011 diagnostic recommendations included: lower threshold values for hemoglobin and hematocrit and bone marrow examination for diagnosis of polycythemia vera (PV), according to the revised WHO criteria; the search for complementary clonal markers, such as ASXL1, EZH2, IDH1/IDH2, and SRSF2 for the diagnosis of myelofibrosis (MF) in patients who test negative for JAK2V617, CALR or MPL driver mutations. Regarding key differences of therapy recommendations, both recombinant interferon alpha and the JAK1/JAK2 inhibitor ruxolitinib are recommended as second-line therapies for PV patients who are intolerant or have inadequate response to hydroxyurea. Ruxolitinib is recommended as first-line approach for MF-associated splenomegaly in patients with intermediate-2 or high-risk disease; in case of intermediate-1 disease, ruxolitinib is recommended in highly symptomatic splenomegaly. Allogeneic stem cell transplantation is recommended for transplant-eligible MF patients with high or intermediate-2 risk score. Allogeneic stem cell transplantation is also recommended for transplant-eligible MF patients with intermediate-1 risk score who present with either refractory, transfusion-dependent anemia, blasts in peripheral blood > 2%, adverse cytogenetics, or high-risk mutations. In these situations, the transplant procedure should be performed in a controlled setting.
Treatment options for myelofibrosis are limited. We evaluated the efficacy and safety of ruxolitinib, a potent and selective Janus kinase (JAK) 1 and 2 inhibitor, as compared with the best available ...therapy, in patients with myelofibrosis.
We assigned 219 patients with intermediate-2 or high-risk primary myelofibrosis, post-polycythemia vera myelofibrosis, or post-essential thrombocythemia myelofibrosis to receive oral ruxolitinib or the best available therapy. The primary end point and key secondary end point of the study were the percentage of patients with at least a 35% reduction in spleen volume at week 48 and at week 24, respectively, as assessed with the use of magnetic resonance imaging or computed tomography.
A total of 28% of the patients in the ruxolitinib group had at least a 35% reduction in spleen volume at week 48, as compared with 0% in the group receiving the best available therapy (P<0.001); the corresponding percentages at week 24 were 32% and 0% (P<0.001). At 48 weeks, the mean palpable spleen length had decreased by 56% with ruxolitinib but had increased by 4% with the best available therapy. The median duration of response with ruxolitinib was not reached, with 80% of patients still having a response at a median follow-up of 12 months. Patients in the ruxolitinib group had an improvement in overall quality-of-life measures and a reduction in symptoms associated with myelofibrosis. The most common hematologic abnormalities of grade 3 or higher in either group were thrombocytopenia and anemia, which were managed with a dose reduction, interruption of treatment, or transfusion. One patient in each group discontinued treatment owing to thrombocytopenia, and none discontinued owing to anemia. Nonhematologic adverse events were rare and mostly grade 1 or 2. Two cases of acute myeloid leukemia were reported with the best available therapy.
Continuous ruxolitinib therapy, as compared with the best available therapy, was associated with marked and durable reductions in splenomegaly and disease-related symptoms, improvements in role functioning and quality of life, and modest toxic effects. An influence on overall survival has not yet been shown. (Funded by Novartis Pharmaceuticals; ClinicalTrials.gov number, NCT00934544.).
Anemia of lower-risk myelodysplastic syndromes (MDSs) and primary myelofibrosis (PMF) generally becomes resistant to available treatments, leading to red blood cell (RBC) transfusions, iron overload, ...shortened survival, and poor quality of life. The transforming growth factor-β superfamily, including activins and growth differentiation factors (GDFs), is aberrantly expressed in lower-risk MDSs and PMF. Luspatercept (and sotatercept), ligand traps that particularly inhibit GDF11, lead to RBC transfusion independence in 10% to 50% of lower-risk MDSs resistant to available treatments, and have started to be used in PMF.
Display omitted
Summary
Fedratinib, an oral Janus kinase‐2 (JAK2) inhibitor, is approved for patients with myelofibrosis (MF) and platelet counts ≥50 × 109/l, based on outcomes from the phase 3, placebo‐controlled ...JAKARTA trial in JAK‐inhibitor‐naïve MF, and the phase 2, single‐arm JAKARTA2 trial in patients previously treated with ruxolitinib. We evaluated the efficacy and safety of fedratinib 400 mg/day in patients with baseline platelet counts 50 to <100 × 109/l (“Low‐Platelets” cohorts), including 14/96 patients (15%) in JAKARTA and 33/97 (34%) in JAKARTA2. At 24 weeks, spleen response rates were not significantly different between the Low‐Platelets cohort and patients with baseline platelet counts ≥100 × 109/l (“High‐Platelets” cohort), in JAKARTA (36% vs. 49%, respectively; p = 0.37) or JAKARTA2 (36% vs. 28%; p = 0.41). Symptom response rates were also not statistically different between the Low‐ and High‐Platelets cohorts. Fedratinib was generally well‐tolerated in both platelet‐count cohorts. New or worsening thrombocytopaenia was more frequent in the Low‐Platelets (44%) versus the High‐Platelets (9%) cohort, but no serious thrombocytopaenia events occurred. Thrombocytopaenia was typically managed with dose modifications; only 3/48 Low‐Platelets patients discontinued fedratinib due to thrombocytopaenia. These data indicate that fedratinib 400 mg/day is safe and effective in patients with MF and low pretreatment platelet counts, and no initial fedratinib dose adjustment is required for these patients.
PDF
