Application of IPSET-thrombosis in 1366 Patients Prospectively Followed From the Spanish Registry of Essential Thrombocythemia

How I approach the treatment of thrombotic complications in patients with myeloproliferative neoplasms

ABSTRACT

Arterial and venous thromboses are the most significant complications in patients with myeloproliferative neoplasms (MPNs), with the primary treatment goal being thrombotic risk reduction. In MPN with no history of thrombosis, primary prevention mainly involves the use of aspirin, and cytoreduction is added in high-risk patients. However, thrombotic complications can unveil an MPN in ∼20% of cases, necessitating the initiation of both antithrombotic therapy for the thrombosis and cytoreductive treatment for the MPN. The duration of anticoagulant therapy after an initial venous thromboembolic event is subject to discussion. Furthermore, the occurrence of a thrombotic complication in patients with a known diagnosis of MPN prompts a reconsideration of both antithrombotic and hematologic management. This review uses case-based discussions to explore the management of thrombotic complications in patients with MPN. It addresses the nature and duration of antithrombotic treatments, as well as the approach to cytoreduction. Special attention is given to the place of direct oral anticoagulants and to the management of patients with MPN with splanchnic vein thrombosis, which is disproportionately common in this group.

New approaches to standard of care in early-phase myeloproliferative neoplasms: can interferon-α alter the natural history of the disease?

The classical BCR::ABL-negative myeloproliferative neoplasms (MPN) include polycythemia vera, essential thrombocythemia, and primary myelofibrosis. They are acquired clonal disorders of hematopoietic stem cells leading to hyperplasia of one or several myeloid lineages. MPN are caused by three main recurrent mutations, JAK2V617F and mutations in the calreticulin (CALR) and thrombopoietin receptor (MPL) genes. Here, we review the general diagnosis, the complications, and the management of MPN. Second, we explain the physiopathology of the natural disease development and its regulation, which contributes to MPN heterogeneity. Thirdly, we describe the new paradigm of MPN development highlighting the early origin of driver mutations, decades before the onset of symptoms, and the consequence of early detection of MPN cases in the general population for prompt diagnosis and better medical management. Finally, we present interferon-α therapy as a potential, early disease-modifying drug after reporting its good hematologic and molecular efficacies in polycythemia vera, essential thrombocythemia, and early myelofibrosis in clinical trials as well as its mechanism of action in pre-clinical studies. As a result, we may expect that, in the future, MPN patients will be diagnosed very early during the course of disease and that new selective therapies under development, such as interferon-α, JAK2V617F inhibitors and CALRmut monoclonal antibodies, will be able to intercept the mutated clones.

Clinical Characteristics, Prognostic Factors, and Thrombotic and Bleeding Outcomes in Philadelphia Chromosome-Negative Myeloproliferative Neoplasms: A Single-Center Cohort Study in Thailand

Background Patients with Philadelphia chromosome-negative myeloproliferative neoplasms (Ph-neg MPNs), including polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF), face elevated risks of thrombosis and major bleeding. Because of these potentially severe complications, antiplatelet and anticoagulant therapies are often employed. This study aimed to evaluate thrombotic and bleeding events, identify associated risk factors, assess prognostic risk models, and investigate the effects of antithrombotic therapy in a Thai cohort of patients with Ph-neg MPNs. Methods This single-center cohort study in Thailand enrolled patients with Ph-neg MPNs from 2013 to 2023. Clinical characteristics, prognostic risk models (International Prognostic Scoring System (IPSS), International Prognostic Score for Essential Thrombocythemia (IPSET)-thrombosis, and Dynamic International Prognostic Scoring System (DIPSS)), and arterial and venous thrombotic events and bleeding complications were analyzed using descriptive statistics, logistic regression, and survival analysis. Results Among 173 patients, PV was the most common subtype (n = 111, 64.2%), with a male predominance and a median age of 57 years. Thrombotic events occurred in 36.9% (n = 41) of PV, 21.4% (n = 3) of PMF, and 18.8% (n = 9) of ET cases, with arterial thrombosis, particularly ischemic stroke, being the most frequent. The JAK2 V617F mutation was prevalent in 72.5% (n = 79) of PV, 70.8% (n = 34) of ET, and 50% (n = 5) of PMF patients. Notably, no major bleeding events were observed despite intensive antithrombotic therapy. Multivariable analysis revealed that prior ischemic stroke (OR 22.51, P = 0.007) and dizziness/headache (OR 7.26, P = 0.022) were significant risk factors for thrombosis. Overall survival (OS) varied by disease subtype. PV patients had a five-year OS of 94.9% and a 10-year OS of 87.2%. ET patients demonstrated a five-year OS of 77.4%. PMF patients had the lowest survival, with a five-year OS of 67.7%. Conclusions This cohort study offers important insights into the clinical characteristics and complication profiles of Ph-neg MPNs in a Thai population. Compared with Western cohorts, patients in this study exhibited a higher incidence of thrombotic events, particularly ischemic stroke. These findings emphasize the need to consider regional variations in disease presentation and underscore the value of individualized risk stratification to optimize patient management in diverse clinical settings.

Essential Thrombocythemia: A Review

Importance

Essential thrombocythemia, a clonal myeloproliferative neoplasm with excessive platelet production, is associated with an increased risk of thrombosis and bleeding. The annual incidence rate of essential thrombocythemia in the US is 1.5/100 000 persons.

Observations

Patients with essential thrombocythemia have a persistent platelet count of 450 × 109/L or greater. The differential diagnosis includes myeloproliferative neoplasms (polycythemia vera, primary myelofibrosis, chronic myeloid leukemia); inflammatory conditions such as rheumatoid arthritis and systemic lupus erythematosus; infections; splenectomy; iron deficiency anemia; and solid tumors such as lung cancer. Approximately 90% of individuals with essential thrombocythemia have genetic variants that upregulate the JAK-STAT (signal transducer and activator of transcription 5) signaling pathway, including Janus kinase 2 (JAK2, 64%), calreticulin (CALR, 23%), and myeloproliferative leukemia virus oncogene (MPL, 4%). The median age at diagnosis of essential thrombocythemia is 59 years. The median overall survival exceeds 35 years in those diagnosed at 40 years or younger. Patients with essential thrombocythemia are at increased risk of arterial thrombosis (11%), venous thrombosis (7%), and hemorrhagic complications (8%). Thrombosis risk is increased among those with a history of thrombosis, age older than 60 years, a JAK2 gene variant, and cardiovascular risk factors (eg, hypertension, diabetes mellitus, hyperlipidemias, tobacco use). Use of aspirin (81-100 mg/d) is suggested for most patients with essential thrombocythemia to lower thrombosis risk. In a retrospective study of 300 affected patients with a low thrombosis risk (younger than 60 years with no prior thrombosis), those not taking aspirin (100 mg/d) had a risk of arterial thrombosis of 9.4/1000 patient-years and a venous thrombosis risk of 8.2/1000 patient years; cardiovascular risk factors were associated with a higher risk of arterial thrombi (incidence rate ratio, 2.5 [95% CI, 1.02-6.1]), and a JAK2 gene variant was associated with increased risk of venous thrombosis (incidence rate ratio, 4.0 [95% CI, 1.2-12.9]). In a randomized trial of 114 patients at higher risk for thrombosis (age older than 60 years or a prior thrombotic event), cytoreduction with hydroxyurea significantly lowered the risk of arterial or venous thrombotic events compared with no cytoreductive therapy (3.6% vs 24%; P < .01). At a median of 8.5 years from diagnosis, approximately 10% of patients with essential thrombocythemia develop myelofibrosis and about 3% develop acute myeloid leukemia.

Conclusions

Essential thrombocythemia is a rare clonal myeloproliferative neoplasm associated with an increased risk of venous and arterial thrombosis, hemorrhage, myelofibrosis, and acute myeloid leukemia. Based on individual risk factors for thrombosis, persons with essential thrombocythemia may be treated with low-dose aspirin, either alone or in combination with a cytoreductive drug such as hydroxyurea.

The clinical significance of TAT, PIC, TM, and t-PAIC in vascular events of BCR/ABL-negative myeloproliferative neoplasms

Predicting the likelihood vascular events in patients with BCR/ABL1-negative myeloproliferative neoplasms (MPN) is essential for the treatment of the disease. However, effective assessment methods are lacking. Thrombin-antithrombin complex (TAT), plasmin-α2- plasmininhibitor complex (PIC), thrombomodulin (TM), and tissue plasminogen activator-inhibitor complex (t-PAIC) are the new direct indicators for coagulation and fibrinolysis. The aim of this study was to investigate the changes of these four new indicators in thrombotic and hemorrhagic events in BCR/ABL1-negative MPN. The study cohort of 74 patients with BCR/ABL negative myeloproliferative disorders included essential thrombocythemia, polycythemia vera, and primary myelofibrosis (PMF). A panel of 4 biomarkers, including TAT, PIC, TM, and t-PAIC were determined using Sysmex HISCL5000 automated analyzers, whereas fibrin/fibrinogen degradation products (FDP), D-dimer and Antithrombin III (ATIII) were analyzed using Sysmex CS5100 coagulation analyzer. A total of 24 (32.4%) patients experienced thrombotic events and hemorrhagic events occurred in 8 patients (10.8%). Compared to patients without hemorrhagic-thrombotic events, patients with thrombotic events had higher fibrinogen (FIB) level, FDP level and lower ATIII activity, while patients with hemorrhagic events had lower white blood cell count and hemoglobin level, higher FDP level (P < 0.05). Patients with a JAK2V617F mutation were more likely to experience thrombotic events (P < 0.05). In addtion, patients with thrombotic events had higher TAT, PIC, TM, and t-PAIC levels than patients without hemorrhagic-thrombotic events (P < 0.05), whereas patients with hemorrhagic events had a lower median value in TAT and TM (no statistical difference, P > 0.05). Patients with higher TAT, TM and t-PAIC were more likely to experience thrombotic events (P < 0.05), and only TAT was positively correlated with thrombotic events (Spearman  r =0.287, P = 0.019). TAT, PIC, TM, and t-PAIC combined with ATIII and FDP have a certain value for predicting thrombosis in patients with BCR/ABL1-negative MPN. These 6 parameters are worth further exploration as predictive factors and prognostic markers for early thrombotic events.

Essential thrombocythaemia: A contemporary approach with new drugs on the horizon

Essential thrombocythaemia (ET) is a myeloproliferative neoplasm characterized by an increased risk of vascular complications and a tendency to progress to myelofibrosis and acute leukaemia. ET patients have traditionally been stratified into two thrombosis risk categories based on age older than 60 years and a history of thrombosis. More recently, the revised IPSET-thrombosis scoring system, which accounts for the increased risk linked to the JAK2 mutation, has been incorporated into most expert recommendations. However, there is increasing evidence that the term ET encompasses different genomic entities, each with a distinct clinical course and prognosis. Moreover, the effectiveness and toxicity of cytoreductive and anti-platelet treatments differ depending on the molecular genotype. While anti-platelets and conventional cytoreductive agents, mainly hydroxycarbamide (hydroxyurea), anagrelide and pegylated interferon, remain the cornerstone of treatment, recent research has shed light on the effectiveness of novel therapies that may help improve outcomes. This comprehensive review focuses on the evolving landscape of treatment strategies in ET, with an emphasis on the role of molecular profiling in guiding therapeutic decisions. Besides evidence-based management according to revised IPSET-thrombosis stratification, we also provide specific observations for those patients with CALR-, MPL-mutated and triple-negative ET, as well as cases with high-risk mutations.

Case report: Peri-procedural hydroxyurea helps minimize bleeding in patients with Essential Thrombocythemia associated with acquired von Willebrand syndrome

Background

Essential Thrombocythemia is a chronic myeloproliferative neoplasm characterized by an isolated excessive production of platelets. Extreme thrombocytosis is defined by having a platelet count greater than or equal to 1,000 x 109/L, which may lead to the development of acquired von Willebrand syndrome and complications of excessive hemorrhage.

Case description

A 74-year-old female patient was brought in for a bone marrow examination regarding elevated platelet count. She had no history of excessive bleeding. The physical exam was unremarkable with no petechiae or hematomas. Complete blood count showed platelet count 1,491x109/L. Bone marrow aspiration and biopsy were unremarkable, however, the patient developed bleeding from the biopsy site. Local pressure and an ice pack were ineffective, so she received 20 mcg of desmopressin subcutaneously, 1 unit of fresh frozen plasma and was started on tranexamic acid 1,000 mg orally every 8 hours. She was admitted for bleeding control and had another dose of desmopressin. Blood work showed elevated partial thromboplastin time and normal international normalized ratio. Acquired von Willebrand syndrome was suspected and a sample for von Willebrand disease was sent out. The next day her bleeding continued, and her Hb decreased from 145 to 89 g/L, she became symptomatic (tachycardic) and fatigued. The coagulation profile was consistent with acquired von Willebrand syndrome. Since she continued bleeding, she received 1 unit of packed red blood cells. A high dose of hydroxyurea (3g/day) was started urgently; within 24 hours platelet count was halved, and the bleeding resolved. Blood work was repeated 24 hours later and showed normalization of partial thromboplastin time and a normal Von Willebrand profile.

Conclusion

Patients with extreme thrombocytosis are at high risk of bleeding due to acquired Von Willebrand Syndrome. Initiation of hydroxyurea at the time of bone marrow exam helps to control platelet count and minimizes the risk of peri-procedural hemorrhage in high-risk Essential Thrombocythemia patients with suspected acquired Von Willebrand Syndrome.

One thousand patients with essential thrombocythemia: the Florence-CRIMM experience

We describe 1000 patients with essential thrombocythemia seen at the Center Research and Innovation of Myeloproliferative Neoplasms (CRIMM), Florence, Italy, between 1980 and 2023: median age 59 years (18-95), females 65%, JAK2/CALR/MPL-mutated 66%/19%/4%, triple-negative (TN) 11%. Extreme thrombocytosis (ExT, platelets ≥1000 × 109/L) in 16%, leukocytosis (leukocytes >11 × 109/L) in 16%, and at least one cardiovascular risk factor in 52% of cases. JAK2-mutated patients were older (median 62 years) and CALR-mutated and TN (53 years for both) younger (p < 0.001). Female gender clustered with TN (76%) and JAK2 (67%) vs CALR (46%) mutations (p < 0.001). ExT clustered with CALR (type-2 more than type-1), TN and MPL, and leukocytosis with JAK2 mutation (p < 0.001). In multivariable analysis, risk factors for arterial thrombosis-free survival were age ≥60 years (HR 2.0; p < 0.001) and JAK2 mutation (HR 1.3; p = 0.02) with borderline significance for male gender (p = 0.08) and cardiovascular risk factors (p = 0.08); for venous thrombosis-free survival, JAK2 mutation (HR 1.9; p = 0.03) with borderline significance for venous thrombosis history (p = 0.07); for overall survival, older age (p < 0.001), male gender (HR 1.9; p < 0.001), absolute neutrophil count (ANC) ≥ 8 × 109/L (HR 1.8; p = 0.01), absolute lymphocyte count (ALC) < 1.7 × 109/L (HR 1.2; p = 0.03); for myelofibrosis-free survival, CALR mutation (HR 2.7; p < 0.001, particularly for CALR type 1/1-like, HR 3.3) and MPL mutation (HR 3.9; p = 0.001); for leukemia-free survival, older age (p = 0.03). Cytoreductive therapy appeared to mitigate both venous (HR 0.3; p = 0.01) and arterial thrombosis (HR 4; p = 0.04); there was a trend for aspirin in preventing arterial thrombosis recurrence. The current study provides real-world observations in essential thrombocythemia, representing a valid source document for interpreting current literature and planning future studies.