Neutrophil-to-lymphocyte ratio is a novel predictor of venous thrombosis in polycythemia vera

Neutrophil/lymphocyte ratio identifies low-risk polycythaemia vera patients for early Ropeginterferon alfa-2b therapy

We investigated the effect of Ropeginterferon alfa-2b (Ropeg) versus phlebotomy-only (Phl-O) on the neutrophil-to-lymphocyte ratio (NLR) in 126 patients randomized in the low-polycythaemia vera (PV) phase II trial. Patients with a baseline NLR ≥3.5 vs. <3.5 had a longer history of PV, were more likely to have splenomegaly, higher JAK2V617F variant allele frequency (VAF) (56% vs. 20% p = 0.001) and more proliferative disease. Ropeg was superior to Phl-O in reducing NLR (p = 0.008), and the reduction was strongly influenced by the reduction in neutrophils and less by a change in lymphocytes (-59% and -14% respectively). This effect was associated with the achievement of the low-PV primary end-point (p = 0.021), symptom reduction and reduction in JAK2 VAF. Interestingly, the reduction in JAK2 VAF from baseline was linearly associated with the reduction in NLR. Patients who failed Phl-O at 12 months had characteristics that distinguished them from responders, including very high NLR and resistance to cross-over to 100 μg Ropeg every 2 weeks suggesting higher escalated doses of Ropeg. In conclusion, the study provides evidence that NLR can serve as a valuable biomarker to assess and guide treatment with Ropeg in the early stage of low-risk PV patients.

Neutrophil-to-lymphocyte and platelet-to-lymphocyte ratio as novel prognostic biomarkers in BCR-ABL negative myeloproliferative neoplasms

Higher neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) have been associated with increased risk of thrombosis, cardiovascular mortality, but their role in myeloproliferative neoplasms (MPN) remains unclear. We analyzed NLR and PLR as prognostic markers for thrombosis and overall survival (OS) in the study that included 461 consecutive MPN patients who were diagnosed from 2018 to 2022 at University center. Twenty age-matched patients without hematological disorder were used as controls. NLR and PLR were significantly increased in whole MPN group compared to controls. NLR was highest in PV > PMF > ET (p < 0.001) while PLR was highest in ET > PMF > PV (p < 0.001). Thrombosis occurrence during follow-up correlated with NLR, NLR ≥ 4.5, presence of ≥ 2 CV factors and previous thrombosis. Arterial thrombosis was associated with previous thrombosis, NLR and NLR ≥ 4.5. Similarly in venous thrombosis previous thrombosis was risk factor, together with NLR, NLR ≥ 4.5, PLR, but also secondary malignancy and female gender. In multivariate Cox model, most important factors for thrombosis development during follow-up were previous thrombosis, NLR ≥ 4.5 and PLR ≥ 500; for arterial thrombosis, NLR ≥ 4.5 and previous thrombosis; for venous thrombosis PLR ≥ 500 and previous thrombosis. Patients with pre-PMF had significantly higher NLR than ET patients. In multivariate Cox regression model, most important factors associated with survival were NLR ≥ 4.5 and PLR ≥ 500. This study highlights strong prognostic correlation of NLR ≥ 4.5 and PLR ≥ 500 with development of thrombosis and OS in MPN. Besides previous thrombosis, most important factor associated with development of arterial thrombosis is NLR ≥ 4.5 and for venous PLR ≥ 500. Our results revealed that NLR ≥ 4.5 could be used as additional marker to distinguish ET from prePMF.

Predictive significance of high neutrophil ratio for thrombosis in myeloproliferative neoplasms: JSH-MPN-R18 subanalysis

Thrombosis in myeloproliferative neoplasms (MPNs) is an important clinical problem, and risk-stratified management is essential. To identify the clinical characteristics of thrombosis in patients with MPNs, a nationwide multi-institutional retrospective analysis (JSH-MPN-R18) was conducted. The aim of the present study was to perform a sub-analysis of JSH-MPN-R18 findings to clarify the predictive parameters for thrombosis among complete blood count (CBC) results. Among the patients enrolled in JSH-MPN-R18, those with essential thrombocythemia (ET; n = 1152) and polycythemia vera (PV; n = 456) were investigated. We analyzed and compared CBC parameters between patients with and those without any thrombotic events using Welch's T-test. Statistical analyses were performed using the R statistical software. Thrombotic events were observed in 74 patients with ET. In multivariate analysis, only the neutrophil ratio was slightly but significantly higher for ET patients with thrombosis than for those without (p < 0.05). Of note, the absolute neutrophil count (aNeu) was considered a useful predictive tool for thrombosis among patients classified as low-risk according to the revised International Prognostic Score of Thrombosis for Essential Thrombocythemia. Among PV patients, those with thrombosis showed significantly higher hematocrit and aNeu than did those without thrombosis. As a thrombosis-associated factor, the neutrophil ratio was slightly but significantly elevated in patients with ET. This myeloid skew might reflect a higher value of JAK2 V617F allelic frequency in patients with ET with thrombosis; this was not clarified in JSH-MPN-R18. Further accumulation of evidence, including genetic information for JAK2 and other passenger mutations, is warranted.

Systemic Inflammatory Index in Polycythemia Vera and Its Prognostic Implications

Background: This study aimed to evaluate the clinical and prognostic associations of the systemic inflammatory index (SII) in polycythemia vera (PV) patients. SII integrates information on absolute neutrophil (ANC), lymphocyte (ALC), and platelet counts into one index (calculated as ANCxALC/platelet count) and was previously shown to predict thrombotic and mortality risks in the general population. Methods: A total of 279 PV patients treated in several hematologic centers in Croatia and Serbia was retrospectively evaluated. Results: The median SII for the overall cohort was 1960. Higher SII stratified at the specific cut-off points was significantly associated with shorter time to thrombosis (TTT; p = 0.004) driven by arterial thrombotic events, and shorter overall survival (OS; p < 0.001). Higher SII was able to refine the European Leukemia Net-defined high-risk patient subgroup for both thrombotic and survival risks, especially in individuals over 60 years of age. SII and all other evaluated CBC components and indices (leukocytes, ANC, ALC, platelets, neutrophil to lymphocyte ratio (NLR), and platelet to lymphocyte ratio (PLR)) demonstrated low-to-modest prognostic properties, whereas SII outperformed other parameters with respect to TTT and OS prognostications. Discussion: The presented results complement prior studies evaluating the prognostic performance of different CBC components for thrombotic and survival risk predictions and offer more options to personalize PV treatments.

Novel germline JAK2R715T mutation causing PV-like erythrocytosis in 3 generations. Amelioration by Ropeg-Interferon

Polycythemia vera (PV) is a clonal disorder arising from the acquired somatic mutations of the JAK2 gene, including JAK2V617F or several others in exon 12. A 38-year-old female had a stroke at age 32 and found to have elevated hemoglobin, normal leukocytes, normal platelets, and tested negative for JAK2V617F and exon 12 mutations. Next generation sequencing revealed a novel mutation: JAK2R715T in the pseudokinase domain (JH2) at 47.5%. Its presence in her nail DNA confirmed a germline origin. Her mother and her son similarly had erythrocytosis and a JAK2R715T mutation. Computer modeling indicated gain-of-function JAK2 activity. The propositus and her mother had polyclonal myelopoiesis, ruling out another somatic mutation-derived clonal hematopoiesis. Some erythroid progenitors of all three generations grew without erythropoietin, a hallmark of PV. The in vitro reporter assay confirmed increased activity of the JAK2R715T kinase. Similar to PV, the JAK2R715T native cells have increased STAT5 phosphorylation, augmented transcripts of prothrombotic and inflammatory genes, and decreased KLF2 transcripts. The propositus was not controlled by hydroxyurea, and JAK2 inhibitors were not tolerated; however, Ropeginterferon-alfa-2b (Ropeg-IFN-α) induced a remission. Ropeg-IFN-α treatment also reduced JAK2 activity in the propositus, her mother and JAK2V617F PV subjects. We report dominantly inherited erythrocytosis secondary to a novel germline JAK2R715T gain-of-function mutation with many but not all comparable molecular features to JAK2V617F PV. We also document a previously unreported inhibitory mechanism of JAK2 signaling by Ropeg-IFN-α.

The role of leukocytes in myeloproliferative neoplasm thromboinflammation

Classic myeloproliferative neoplasms lacking the Philadelphia chromosome are stem cell disorders characterized by the proliferation of myeloid cells in the bone marrow and increased counts of peripheral blood cells. The occurrence of thrombotic events is a common complication in myeloproliferative neoplasms. The heightened levels of cytokines play a substantial role in the morbidity and mortality of these patients, establishing a persistent proinflammatory condition that culminates in thrombosis. The etiology of thrombosis remains intricate and multifaceted, involving blood cells and endothelial dysfunction, the inflammatory state, and the coagulation cascade, leading to hypercoagulability. Leukocytes play a pivotal role in the thromboinflammatory process of myeloproliferative neoplasms by releasing various proinflammatory and prothrombotic factors as well as interacting with other cells, which contributes to the amplification of the clotting cascade and subsequent thrombosis. The correlation between increased leukocyte counts and thrombotic risk has been established. However, there is a need for an accurate biomarker to assess leukocyte activation. Lastly, tailored treatments to address the thrombotic risk in myeloproliferative neoplasms are needed. Therefore, this review aims to summarize the potential mechanisms of leukocyte involvement in myeloproliferative neoplasm thromboinflammation, propose potential biomarkers for leukocyte activation, and discuss promising treatment options for controlling myeloproliferative neoplasm thromboinflammation.

TFPI from erythroblasts drives heme production in central macrophages promoting erythropoiesis in polycythemia

Bleeding and thrombosis are known as common complications of polycythemia for a long time. However, the role of coagulation system in erythropoiesis is unclear. Here, we discover that an anticoagulant protein tissue factor pathway inhibitor (TFPI) plays an essential role in erythropoiesis via the control of heme biosynthesis in central macrophages. TFPI levels are elevated in erythroblasts of human erythroblastic islands with JAK2V617F mutation and hypoxia condition. Erythroid lineage-specific knockout TFPI results in impaired erythropoiesis through decreasing ferrochelatase expression and heme biosynthesis in central macrophages. Mechanistically, the TFPI interacts with thrombomodulin to promote the downstream ERK1/2-GATA1 signaling pathway to induce heme biosynthesis in central macrophages. Furthermore, TFPI blockade impairs human erythropoiesis in vitro, and normalizes the erythroid compartment in mice with polycythemia. These results show that erythroblast-derived TFPI plays an important role in the regulation of erythropoiesis and reveal an interplay between erythroblasts and central macrophages.

The Systemic Inflammation Index: A New Candidate Minor Criterion in the Diagnosis of Polycythemia Vera

AIM

To investigate inflammation indices and erythropoietin levels for their potential role in distinguishing polycythemia vera from secondary polycythemia and to compare different parameter combinations in terms of the diagnostic accuracy.

METHODS

This retrospective cohort was created from patients assessed for polycythemia from January 2020 to December 2023. Polycythemia vera diagnosis was made according to the 2016 World Health Organization criteria (n = 145). Those who did not fulfill the criteria were defined as having secondary polycythemia (n = 84).

RESULTS

The neutrophil lymphocyte ratio, platelet lymphocyte ratio and systemic immune-inflammation index were significantly higher in the polycythemia vera group (p < 0.001 for all). Erythropoietin had the highest area under the curve in the analysis to distinguish groups, followed by the systemic immune-inflammation index. The platelet lymphocyte ratio (≥135) had the highest specificity to detect polycythemia vera, followed closely by the systemic immune-inflammation index. The sensitivity for polycythemia vera detection was highest with the erythropoietin and systemic immune-inflammation index combination, followed by erythropoietin and the neutrophil lymphocyte ratio. All the single and combinatory variables exhibited significant performance in predicting polycythemia vera after adjusting for age and sex. However, the erythropoietin and systemic immune-inflammation index combination had the highest odds ratio, followed by erythropoietin alone.

CONCLUSION

These are promising findings supporting the usability of these biomarkers, especially the systemic immune-inflammation index, as minor criteria in the diagnosis of polycythemia vera. It is especially crucial to note that using erythropoietin in combination with these markers may improve diagnostic accuracy.

ADAMTS13, von Willebrand Factor, Platelet Microparticles, Factor VIII, and Impact of Somatic Mutations in the Pathogenesis of Splanchnic Vein Thrombosis Associated with BCR-ABL-Negative Myeloproliferative Neoplasms

BACKGROUND

Myeloproliferative neoplasms (MPNs) are often associated with splanchnic vein thrombosis (SVT). Not all the factors involved in the thrombotic tendency are currently known.

OBJECTIVES

This study aims to evaluate a possible association between ADAMTS13, von Willebrand factor (VWF), platelet microvesicles (MV), and factor VIII activity (FVIII:C) with thrombotic events in MPN patients.

MATERIALS AND METHODS

In total, 36 consecutive MPN patients with SVT were enrolled. The MPNs were diagnosed based on clinical characteristics and one or more gene mutations among JAK-2, CALR, and MPL. As controls, 50 randomly selected patients with MPN without thrombosis, 50 patients with deep vein thrombosis without MPNs, and 50 healthy blood donors were evaluated. Complete blood count, ADAMTS13, VWF, MV, and FVIII:C in plasma were measured in all the subjects.

RESULTS

The JAK-2 mutation was found in 94% of the patients with SVT, but none were triple-negative for genetic mutations (JAK2 V617F, CALR, MPL, and exon 12). Compared to the normal subjects, in all the MPN patients (with or without SVT), the levels of ADAMTS13 were found to be significantly lower (p < 0.001) and the MV concentrations were significantly higher (p < 0.001). Among the MPN patients, the VWF and FVIII:C levels were significantly higher in the patients with SVT than those without thrombosis (p = 0.007 and p = 0.04, respectively). Splenomegaly was present in 78% of MPN patients with SVT and in 30% of those without SVT (p < 0.001). The ADAMTS13/VWF ratio was reduced in all the patients, but not in the healthy blood donors (p < 0.001).

CONCLUSIONS

The significant increase in circulating MV, VWF, and FVIII:C in the MPN patients and in the patients with thrombosis supports the role of endothelium damage in promoting thrombotic events. In particular, a significant increase in VWF and FVIII:C levels was found in the MPN patients with SVT.

Association of the neutrophil-to-lymphocyte ratio with the occurrence of venous thromboembolism and arterial thrombosis

OBJECTIVE

This study aimed to assess the association of the neutrophil-to-lymphocyte ratio (NLR) with the occurrence of venous thromboembolism (VTE) and arterial thrombosis (AT).

METHODS

This was a retrospective cross-sectional study including 585 medical records obtained from all consecutive patients who were suspected of having thrombosis.

RESULTS

The AT group had a higher neutrophil count and NLR and a lower lymphocyte count than the non-thrombosis group. Receiver operating characteristic curve analysis showed the ability of the NLR to predict the presence of AT. The cut-off value for the NLR was 4.44. No distinction was found in the NLR between the VTE and non-thrombosis groups. Regression analysis showed that a high NLR was an independent factor related to the presence of AT. Patients with an NLR ≥ 4.44 had a higher risk of AT than those with an NLR < 4.44 (odds ratio = 2.015, 95% confidence interval: 1.180-3.443).

CONCLUSION

A high NLR may be considered a predictive factor for the occurrence of AT, but an association with the presence of VTE was not found.

Rusfertide, a Hepcidin Mimetic, for Control of Erythrocytosis in Polycythemia Vera

BACKGROUND

Polycythemia vera is a chronic myeloproliferative neoplasm characterized by erythrocytosis. Rusfertide, an injectable peptide mimetic of the master iron regulatory hormone hepcidin, restricts the availability of iron for erythropoiesis. The safety and efficacy of rusfertide in patients with phlebotomy-dependent polycythemia vera are unknown.

METHODS

In part 1 of the international, phase 2 REVIVE trial, we enrolled patients in a 28-week dose-finding assessment of rusfertide. Part 2 was a double-blind, randomized withdrawal period in which we assigned patients, in a 1:1 ratio, to receive rusfertide or placebo for 12 weeks. The primary efficacy end point was a response, defined by hematocrit control, absence of phlebotomy, and completion of the trial regimen during part 2. Patient-reported outcomes were assessed by means of the modified Myeloproliferative Neoplasm Symptom Assessment Form (MPN-SAF) patient diary (scores range from 0 to 10, with higher scores indicating greater severity of symptoms).

RESULTS

Seventy patients were enrolled in part 1 of the trial, and 59 were assigned to receive rusfertide (30 patients) or placebo (29 patients) in part 2. The estimated mean (±SD) number of phlebotomies per year was 8.7±2.9 during the 28 weeks before the first dose of rusfertide and 0.6±1.0 during part 1 (estimated difference, 8.1 phlebotomies per year). The mean maximum hematocrit was 44.5±2.2% during part 1 as compared with 50.0±5.8% during the 28 weeks before the first dose of rusfertide. During part 2, a response was observed in 60% of the patients who received rusfertide as compared with 17% of those who received placebo (P = 0.002). Between baseline and the end of part 1, rusfertide treatment was associated with a decrease in individual symptom scores on the MPN-SAF in patients with moderate or severe symptoms at baseline. During parts 1 and 2, grade 3 adverse events occurred in 13% of the patients, and none of the patients had a grade 4 or 5 event. Injection-site reactions of grade 1 or 2 in severity were common.

CONCLUSIONS

In patients with polycythemia vera, rusfertide treatment was associated with a mean hematocrit of less than 45% during the 28-week dose-finding period, and the percentage of patients with a response during the 12-week randomized withdrawal period was greater with rusfertide than with placebo. (Funded by Protagonist Therapeutics; REVIVE ClinicalTrials.gov number, NCT04057040.).

Neutrophil-to-lymphocyte ratio and all-cause mortality with and without myeloproliferative neoplasms-a Danish longitudinal study

The neutrophil-to-lymphocyte ratio(NLR) is increased in chronic inflammation and myeloproliferative neoplasms (MPN). We hypothesize that NLR is associated with all-cause mortality and mortality by comorbidity burden in the general population and individuals with MPN. We included 835,430 individuals from The Danish General Suburban Population Study, general practitioners, and outpatient clinics. We investigated NLR on mortality stratified by prevalent and incident MPN, essential thrombocythemia (ET), polycythemia vera (PV), myelofibrosis (MF), comorbidity burden (CCI-score), and the Triple-A risk score using hazard ratio (HR) and 95% confidence interval (95%CI). NLR 1-1.9 was the reference level. During a median follow-up of 11.2 years, 197,802 deaths were recorded. All-cause mortality increased for a stepwise increasing NLR with a HR (95%CI) for NLR ≥ 6 of 2.06(2.03-2.09) for the whole population and 2.93(2.44-3.50) in prevalent MPN. ET, PV, and MF had a HR (95%CI) for NLR ≥ 2 of 2.14(1.71-2.69), 2.19(1.89-2.54), and 2.31(1.91-2.80). Results were similar for incident MPN. Mortality was higher for stepwise increasing NLR and CCI-score(pinteraction < 2×10-16), with a HR for NLR ≥ 6 of 2.23(2.17-2.29), 4.10(4.01-4.20), and 7.69(7.50-7.89), for CCI-score 0, 1-2, or ≥3. The Triple-A risk score demonstrated alignment with NLR. Increasing NLR and comorbidity burden were associated with lower survival in individuals without MPN but were even worse in prevalent and incident MPN, ET, PV, and MF.

Distinct clinico-molecular arterial and venous thrombosis scores for myeloproliferative neoplasms risk stratification

Current recommended risk scores to predict thrombotic events associated with myeloproliferative neoplasms (MPN) do not discriminate between arterial and venous thrombosis despite their different physiopathology. To define novel stratification systems, we delineated a comprehensive landscape of MPN associated thrombosis across a large long-term follow-up MPN cohort. Prior arterial thrombosis, age >60 years, cardiovascular risk factors and presence of TET2 or DNMT3A mutations were independently associated with arterial thrombosis in multivariable analysis. ARTS, an ARterial Thrombosis Score, based on these four factors, defined low- (0.37% patients-year) and high-risk (1.19% patients-year) patients. ARTS performance was superior to the two-tiered conventional risk stratification in our training cohort, across all MPN subtypes, as well as in two external validation cohorts. Prior venous thrombosis and presence of a JAK2V617F mutation with a variant allelic frequency ≥50% were independently associated with venous thrombosis. The discrimination potential of VETS, a VEnous Thrombosis Score based on these two factors, was poor, similar to the two-tiered conventional risk stratification. Our study pinpoints arterial and venous thrombosis clinico-molecular differences and proposes an arterial risk score for more accurate patients' stratification. Further improvement of venous risk scores, accounting for additional factors and considering venous thrombosis as a heterogeneous entity is warranted.

Activated PRKCD-mediated neutrophil extracellular traps pathway may be the prothrombotic mechanism of neutrophils in polycythemia vera patients based on clinical retrospective analysis and bioinformatics study

Thrombosis is a major cause of morbimortality in patients with polycythemia vera (PV). Furthermore, neutrophils play a significant role in thrombosis, but their role in the pathogenetic mechanisms of PV is not well characterized. Therefore, we investigated the role and mechanisms by which neutrophils regulate thrombosis in PV patients. Univariate and multivariate logistic regression analysis of clinicopathological factors was performed to determine the independent risk factors of thrombosis in PV. Pearson's correlation analysis was performed to determine the relationship between absolute neutrophil count (ANC) and the hypercoagulable state in PV patients. Bioinformatics analysis of the GSE54644 dataset was used to identify hemostasis-related pathways in neutrophils of PV patients. Weighted gene co-expression network analysis (WGCNA) of the integrated dataset (GSE57793, GSE26049 and GSE61629) was used to identify neutrophils-related genes and pathways associated with thrombosis in PV. Ingenuity pathway analysis (IPA) was performed to identify the differentially activated pathways in PV patients with or without thrombosis using GSE47018 dataset. Our data showed increased ANC in PV patients. Multivariate logistic regression analysis showed that ANC was an independent risk factor for the thrombotic events in PV patients before or at diagnosis. ANC correlated with the hypercoagulable state in PV patients. Neutrophil extracellular traps (NETs) pathway was significantly enriched in the neutrophils of PV patients. IPA results demonstrated that PRKCD-mediated NETs pathway was hyperactivated in PV patients with thrombosis. In summary, ANC was an independent risk factor for the thrombotic events in PV patients before or at diagnosis, and PRKCD-mediated NETs pathway was aberrantly activated in the neutrophils of PV patients and was associated with the thrombotic events.

Association of inflammation and abnormal lipid metabolism with risk of thrombosis and thrombosis progression in patients with polycythemia vera: a retrospective study

To date, no therapeutic strategy has been shown to be effective in reducing the risk of polycythemia vera (PV) transforming into myelofibrosis or leukemia, and the main goal of current treatment is to prevent thrombotic events. Recent studies have shown that higher levels of inflammation are associated with an increased risk of thrombosis in PV patients, while the correlation between inflammation and abnormal lipid metabolism with the risk of thrombosis in PV has not been reported. In this retrospective study, 148 patients with newly diagnosed PV who visited the Affiliated Hospitals of Nanchang University from January 2013 to June 2023 were categorized into low-risk group and high-risk group according to the risk of thrombosis, and were subsequently divided into thrombosis non-progression group and progression group. The differences of novel inflammatory markers PHR, NHR, MHR, LHR, and SIRI in each group were analyzed and compared with healthy adults who underwent physical examination in the hospitals during the same period. The results showed that PHR, NHR, MHR, and SIRI levels were significantly higher in the PV group than in the control group (P < 0.001), while HDL-C levels were considerably lower (1.09 vs. 1.31, P < 0.001). Comparisons within the groups of PV patients revealed that PHR, MHR, NHR, NLR, and SIRI levels were significantly higher in the high-risk group for thrombosis than in the low-risk group (P < 0.01); the thrombosis PHR, NHR, NLR, and SIRI levels were higher in the group with progression of thrombosis than in the group without progression of thrombosis (P < 0.05), while HDL-C levels were significantly lower (1.02 vs. 1.12, P < 0.001). The results of the ROC curve analysis showed that NHR (AUC = 0.791), HDL-C (AUC = 0.691), PHR (AUC = 0.668), NLR(AUC = 0.658), and SIRI (AUC = 0.638) had high diagnostic efficacy for identifying PV patients with thrombosis progression. Multivariate analysis showed that NHR, NLR, MHR, and LHR were independent risk factors for PV patients with thrombosis progression (P < 0.05). Kaplan-Meier survival curves showed that NHR ≥ 5.82 × 109/mmol, NLR ≥ 6.295, PHR ≥ 280.4 × 109/mmol, MHR ≥ 0.295 × 109/mmol, LHR ≥ 1.41 × 109/mmol, and SIRI ≥ 1.53 × 109/L were risk factors for PFS in PV patients. The study demonstrates for the first time that novel inflammatory markers PHR, NHR, MHR, LHR, and SIRI may be used as new predictors for PV patients with thrombosis progression. NHR has the highest value in predicting thrombosis in PV patients and is superior to NLR which was reported previously.

A globally applicable "triple A" risk model for essential thrombocythemia based on Age, Absolute neutrophil count, and Absolute lymphocyte count

We examined the individual prognostic contribution of absolute neutrophil (ANC), lymphocyte (ALC), and monocyte (AMC) counts, on overall (OS), leukemia-free (LFS), and myelofibrosis-free (MFFS) survival in essential thrombocythemia (ET). Informative cases (N = 598; median age 59 years; females 62%) were retrospectively accrued from a Mayo Clinic database: JAK2 59%, CALR 27%, triple-negative 11%, and MPL 3%; international prognostic scoring system for ET (IPSET) risk high 21%, intermediate 42%, and low 37%; 7% (37/515) had abnormal karyotype and 10% (21/205) adverse mutations (SF3B1/SRSF2/U2AF1/TP53). At median 8.4 years, 163 (27%) deaths, 71 (12%) fibrotic, and 20 (3%) leukemic transformations were recorded. Multivariable analysis resulted in HR (95% CI) of 16.5 (9.9-27.4) for age > 70 years, 3.7 (2.3-6.0) for age 50-70 years, 2.4 (1.7-3.3) for ANC ≥8 × 109 /L, and 1.9 (1.4-2.6) for ALC <1.7 × 109 /L. The corresponding HR-based scores were 4, 2, 1, and 1, resulting in an new 4-tiered AgeAncAlc (AAA; triple A) risk model: high (5-6 points; median survival 8 years; HR 30.1, 95% CI 17.6-54), intermediate-2 (4 points; median 13.5 years; HR 12.7, 95% CI 7.1-23.0), intermediate-1 (2-3 points; median 20.7 years; HR 3.8, 95% CI 2.3-6.4) and low (0-1 points; median 47 years). The AAA model (Akaike Information Criterion [AIC] 621) performed better than IPSET (AIC 647) and was subsequently validated by an external University of Florence ET cohort (N = 485). None of the AAA variables predicted LFS while ALC <1.7 × 109 /L was associated with inferior MFFS (p = .01). Adverse mutations (p < .01) and karyotype (p < .01) displayed additional prognostic value without disqualifying the prognostic integrity of the AAA model. This study proposes a simple and globally applicable survival model for ET, which can be used as a platform for further molecular refinement. This study also suggests a potential role for immune-related biomarkers, as a prognostic tool in myeloproliferative neoplasms.

Clinical variables associated with late-onset thrombotic and cardiovascular events, after SARS-CoV-2 infection, in a cohort of patients from the first epidemic wave: an 18-month analysis on the "Surviving-COVID" cohort from Bergamo, Italy

Importance

Population studies have recorded an increased, unexplained risk of post-acute cardiovascular and thrombotic events, up to 1 year after acute severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection.

Objectives

To search for clinical variables and biomarkers associated with late post-acute thrombotic and cardiovascular events after SARS-CoV-2 infection.

Design

Retrospective cohort study.

Setting

Third-level referral hospital in Bergamo (Italy).

Participants

Analysis of an existing database of adult patients, who received care for SARS-CoV-2 infection at our institution between 20 February and 30 September 2020, followed up on a single date ("entry date") at 3-6 months.

Exposure

Initial infection by SARS-CoV-2.

Main outcomes and measures

Primary outcome: occurrence, in the 18 months after entry date, of a composite endpoint, defined by the International Classification of Diseases-9th edition (ICD-9) codes for at least one of: cerebral/cardiac ischemia, venous/arterial thrombosis (any site), pulmonary embolism, cardiac arrhythmia, heart failure. Measures (as recorded on entry date): history of initial infection, symptoms, current medications, pulmonary function test, blood tests results, and semi-quantitative radiographic lung damage (BRIXIA score). Individual clinical data were matched to hospitalizations, voluntary vaccination against SARS-CoV-2 (according to regulations and product availability), and documented reinfections in the following 18 months, as recorded in the provincial Health Authority database. A multivariable Cox proportional hazard model (including vaccine doses as a time-dependent variable) was fitted, adjusting for potential confounders. We report associations as hazard ratios (HR) and 95% confidence intervals (CI).

Results

Among 1,515 patients (948 men, 62.6%, median age 59; interquartile range: 50-69), we identified 84 endpoint events, occurring to 75 patients (5%): 30 arterial thromboses, 11 venous thromboses, 28 arrhythmic and 24 heart failure events. From a multivariable Cox model, we found the following significant associations with the outcome: previous occurrence of any outcome event, in the 18 months before infection (HR: 2.38; 95% CI: 1.23-4.62); BRIXIA score ≥ 3 (HR: 2.43; 95% CI: 1.30-4.55); neutrophils-to-lymphocytes ratio ≥ 3.3 (HR: 2.60; 95% CI: 1.43-4.72), and estimated glomerular filtration rate < 45 ml/min/1.73 m2 (HR: 3.84; 95% CI: 1.49-9.91).

Conclusions and relevance

We identified four clinical variables, associated with the occurrence of post-acute thrombotic and cardiovascular events, after SARS-CoV-2 infection. Further research is needed, to confirm these results.

Relevant Clinical Factors in Patients with Myelofibrosis on Ruxolitinib for 5 or More Years

INTRODUCTION

Median duration of therapy with the first JAK1/2 inhibitor ruxolitinib (RUX) approved for patients with intermediate or high-risk myelofibrosis (MF) is about 3 years.

METHODS

In this retrospective study, we aimed to evaluate clinical features, predictive factors, and outcome of patients presenting to our institution who were able to remain on RUX for ≥5 years (RUX ≥5y, n = 73).

RESULTS

Comparing baseline demographics of patients who remained on RUX ≥5y (n = 73) with patients who were on RUX for 6 months to 3 years (n = 203), we confirmed that patients on RUX ≥5y lacked advanced clinical features at the start of therapy, such as anemia, neutropenia, thrombocytopenia, higher blasts or monocytes. Predictive independent factors for staying on RUX ≥5y were hemoglobin >10 g/dL, circulating blasts <1%, platelets >150 × 109/L, neutrophils >70%, and having primary MF. Age over 65 years remained significant for outcome in patients on RUX ≥5y.

CONCLUSION

In this retrospective study, we report on the relevance of absence of advanced clinical features for long RUX therapy and confirm the role of age on outcome despite therapy.

Polycythemia vera: 2024 update on diagnosis, risk-stratification, and management

DISEASE OVERVIEW

Polycythemia vera (PV) is a JAK2-mutated myeloproliferative neoplasm characterized by clonal erythrocytosis; other features include leukocytosis, thrombocytosis, splenomegaly, pruritus, constitutional symptoms, microcirculatory disturbances, and increased risk of thrombosis and progression into myelofibrosis (post-PV MF) or acute myeloid leukemia (AML).

DIAGNOSIS

A working diagnosis is considered in the presence of a JAK2 mutation associated with hemoglobin/hematocrit levels of >16.5 g/dL/49% in men or 16 g/dL/48% in women; morphologic confirmation by bone marrow examination is advised but not mandated.

CYTOGENETICS

Abnormal karyotype is seen in 15%-20% of patients with the most frequent sole abnormalities being +9 (5%), loss of chromosome Y (4%), +8 (3%), and 20q- (3%).

MUTATIONS

Over 50% of patients harbor DNA sequence variants/mutations other than JAK2, with the most frequent being TET2 (18%) and ASXL1 (15%). Prognostically adverse mutations include SRSF2, IDH2, RUNX1, and U2AF1, with a combined incidence of 5%-10%.

SURVIVAL AND PROGNOSIS

Median survival is ⁓15 years but exceeds 35 years for patients aged ≤40 years. Risk factors for survival include older age, leukocytosis, abnormal karyotype, and the presence of adverse mutations. Twenty-year risk for thrombosis, post-PV MF, or AML are ⁓26%, 16% and 4%, respectively.

RISK FACTORS FOR THROMBOSIS

Two risk categories are considered: high (age >60 years or thrombosis history) and low (absence of both risk factors). Additional predictors for arterial thrombosis include cardiovascular risk factors and for venous thrombosis higher absolute neutrophil count and JAK2V617F allele burden.

TREATMENT

Current goal of therapy is to prevent thrombosis. Periodic phlebotomy, with a hematocrit target of <45%, combined with once- or twice-daily aspirin (81 mg) therapy, absent contraindications, is the backbone of treatment in all patients, regardless of risk category. Cytoreductive therapy is reserved for high-risk disease with first-line drugs of choice being hydroxyurea and pegylated interferon-α and second-line busulfan and ruxolitinib. In addition, systemic anticoagulation is advised in patients with venous thrombosis history.

ADDITIONAL TREATMENT CONSIDERATIONS

At the present time, we do not consider a drug-induced reduction in JAK2V617F allele burden, which is often incomplete and seen not only with peg-IFN but also with ruxolitinib and busulfan, as an indicator of disease-modifying activity, unless accompanied by cytogenetic and independently-verified morphologic remission. Accordingly, we do not use the specific parameter to influence treatment choices. The current review also includes specific treatment strategies in the context of pregnancy, splanchnic vein thrombosis, pruritus, perioperative care, and post-PV MF.

Identifying Patients with Polycythemia Vera at Risk of Thrombosis after Hydroxyurea Initiation: The Polycythemia Vera-Advanced Integrated Models (PV-AIM) Project

Patients with polycythemia vera (PV) are at significant risk of thromboembolic events (TE). The PV-AIM study used the Optum® de-identified Electronic Health Record dataset and machine learning to identify markers of TE in a real-world population. Data for 82,960 patients with PV were extracted: 3852 patients were treated with hydroxyurea (HU) only, while 130 patients were treated with HU and then changed to ruxolitinib (HU-ruxolitinib). For HU-alone patients, the annualized incidence rates (IR; per 100 patients) decreased from 8.7 (before HU) to 5.6 (during HU) but increased markedly to 10.5 (continuing HU). Whereas for HU-ruxolitinib patients, the IR decreased from 10.8 (before HU) to 8.4 (during HU) and was maintained at 8.3 (after switching to ruxolitinib). To better understand markers associated with TE risk, we built a machine-learning model for HU-alone patients and validated it using an independent dataset. The model identified lymphocyte percentage (LYP), neutrophil percentage (NEP), and red cell distribution width (RDW) as key markers of TE risk, and optimal thresholds for these markers were established, from which a decision tree was derived. Using these widely used laboratory markers, the decision tree could be used to identify patients at high risk for TE, facilitate treatment decisions, and optimize patient management.

Ten-Year Multicenter Retrospective Study Utilizing Machine Learning Algorithms to Identify Patients at High Risk of Venous Thromboembolism After Radical Gastrectomy

Purpose

This study aims to construct a machine learning model that can recognize preoperative, intraoperative, and postoperative high-risk indicators and predict the onset of venous thromboembolism (VTE) in patients.

Patients and Methods

A total of 1239 patients diagnosed with gastric cancer were enrolled in this retrospective study, among whom 107 patients developed VTE after surgery. We collected 42 characteristic variables of gastric cancer patients from the database of Wuxi People's Hospital and Wuxi Second People's Hospital between 2010 and 2020, including patients' demographic characteristics, chronic medical history, laboratory test characteristics, surgical information, and patients' postoperative conditions. Four machine learning algorithms, namely, extreme gradient boosting (XGBoost), random forest (RF), support vector machine (SVM), and k-nearest neighbor (KNN), were employed to develop predictive models. We also utilized Shapley additive explanation (SHAP) for model interpretation and evaluated the models using k-fold cross-validation, receiver operating characteristic (ROC) curves, calibration curves, decision curve analysis (DCA), and external validation metrics.

Results

The XGBoost algorithm demonstrated superior performance compared to the other three prediction models. The area under the curve (AUC) value for XGBoost was 0.989 in the training set and 0.912 in the validation set, indicating high prediction accuracy. Furthermore, the AUC value of the external validation set was 0.85, signifying good extrapolation of the XGBoost prediction model. The results of SHAP analysis revealed that several factors, including higher body mass index (BMI), history of adjuvant radiotherapy and chemotherapy, T-stage of the tumor, lymph node metastasis, central venous catheter use, high intraoperative bleeding, and long operative time, were significantly associated with postoperative VTE.

Conclusion

The machine learning algorithm XGBoost derived from this study enables the development of a predictive model for postoperative VTE in patients after radical gastrectomy, thereby assisting clinicians in making informed clinical decisions.

The Discovery of an Intracardiac Thrombus Following a Mild COVID-19 Infection: A Case Report and Review of Literature

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) (COVID-19) is a viral disease that predominantly affects the respiratory system, but extrapulmonary manifestations have been increasingly reported over the course of the pandemic. Common extrapulmonary manifestations include the gastrointestinal, cardiovascular, and neurological systems, such as diarrhea, rashes, loss of smell/taste, myalgia, acute kidney injury, cardiac arrhythmias, or heart failure. COVID-19 infection is associated with an increased risk of thromboembolic events, especially in the setting of severe disease. We present a case of a 42-year-old female who recently tested positive for COVID-19 infection and presented to the clinic with complaints of palpitations that started after her diagnosis. An electrocardiogram done in the clinic showed sinus rhythm, and the patient was placed on an event monitor, which showed no evidence of tachyarrhythmia. A transthoracic echocardiogram (TTE) done as part of the workup showed a large thrombus in the right ventricular outflow tract attached to the ventricular side of the pulmonic valve. The patient was started on a therapeutic dose of apixaban at 10 mg twice a day (BID) for seven days and 5 mg twice a day afterward.

Novel therapeutic strategies for essential thrombocythemia/polycythemia vera

Myeloproliferative neoplasms (MPNs) are clonal disorders of hematopoietic stem cells; these include polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF). MPNs are inflammatory cancers, wherein the malignant clone generates cytokines that sustain the inflammatory drive in a self-perpetuating vicious cycle. The course of MPNs follows a biological continuum, that is, from early cancer stages (ET/PV) to advanced myelofibrosis as well as impending leukemic transformation. MPN-related symptoms, e.g., fatigue, general weakness, and itching, are caused by inflammatory cytokines. Thrombosis and bleeding are also exacerbated by inflammatory cytokines in patients with MPN. Until recently, the primary objective of ET and PV therapy was to increase survival rates by preventing thrombosis. However, several medications have recently demonstrated the ability to modify the course of the disease; symptom relief is expected for most patients. In addition, there is increasing interest in the active treatment of patients at low risk with PV and ET. This review focuses on the ET/PV treatment strategies as well as novel treatment options for clinical development.

Diagnosis and Management of Cerebral Venous Thrombosis Due to Polycythemia Vera and Genetic Thrombophilia: Case Report and Literature Review

(1) Background: Cerebral venous and dural sinus thrombosis (CVT) rarely appears in the adult population. It is difficult to diagnosis because of its variable clinical presentation and the overlapping signal intensities of thrombosis and venous flow on conventional MR images and MR venograms. (2) Case presentation: A 41-year-old male patient presented with an acute isolated intracranial hypertension syndrome. The diagnosis of acute thrombosis of the left lateral sinus (both transverse and sigmoid portions), the torcular Herophili, and the bulb of the left internal jugular vein was established by neuroimaging data from head-computed tomography, magnetic resonance imaging (including Contrast-enhanced 3D T1-MPRAGE sequence), and magnetic resonance venography (2D-TOF MR venography). We detected different risk factors (polycythemia vera-PV with JAK2 V617F mutation and inherited low-risk thrombophilia). He was successfully treated with low-molecular-weight heparin, followed by oral anticoagulation. (3) Conclusions: In the case of our patient, polycythemia vera represented a predisposing risk factor for CVT, and the identification of JAK2 V617F mutation was mandatory for the etiology of the disease. Contrast-enhanced 3D T1-MPRAGE sequence proved superior to 2D-TOF MR venography and to conventional SE MR imaging in the diagnosis of acute intracranial dural sinus thrombosis.

Leukocytosis and MPNs: Where do we stand?

The Philadelphia-negative myeloproliferative neoplasms (MPNs)-essential thrombocythemia (ET), polycythemia vera (PV) and myelofibrosis (MF), are characterized by a propensity for thrombotic events and variable risks for transformation to MF (for ET and PV) and acute leukemia. Leukocytosis, which serves a minor criterion for the diagnosis of MF, is present in a significant portion of patients with MPNs. The relation and impact of leukocytosis on disease course and outcomes of patients with MPNs has been studied in multiple, large retrospective and prospective studies. Despite this, the association of leukocytosis and thrombosis, fibrosis and leukemic transformation remains unclear. This article details the published investigations regarding the impact of leukocytosis in MPNs and explores the changing role of leukocytosis in disease prognostication as increasing emphasis is placed on molecular and genetic studies.

SOHO State of the Art Updates and Next Questions | Polycythemia Vera: Is It Time to Rethink Treatment?

Polycythemia vera (PV) is a Philadelphia-negative myeloproliferative neoplasm characterized by excessive myeloid cells production, mostly secondary to mutations in the Janus kinase 2 (JAK2) gene. PV natural history might be burdened by thrombotic events (TEs) and evolution into post-PV myelofibrosis (PPV-MF) or blast phase (BP). To date, no treatment strategies have been shown to have disease modifying effects, so therapy is directed at preventing TEs. All patients require phlebotomies (PHLs) to keep hematocrit below 45% and once-daily low dose aspirin (if not contraindicated). Apart from patients at "high risk" because of age over 60 years or a thrombosis history, cytoreductive therapies (CT) should be given to patients with relevant signs of myeloproliferation or intolerance to PHLs. Approved choices both for first and second line CT are hydroxyurea (HU) and pegylated forms of interferon (peg-IFN), the latter probably being better for young patients, and subjects without critical and recent vascular events or massive splenomegaly. The JAK1/2 inhibitor ruxolitinib is the treatment of choice in case of resistance/intolerance to HU, with proved efficacy in terms of thrombotic prevention. Data are too preliminary to consider CT for "low risk" PV cases, but ropeg-IFN is being studied in this setting with a short follow-up. A careful monitoring for signs of evolution into PPV-MF is fundamental for optimizing patient management.

TET2 Mutation May Be More Valuable in Predicting Thrombosis in ET Patients Compared to PV Patients: A Preliminary Report

Thrombosis is a common complication of myeloproliferative neoplasm (MPN), and it is a major cause of disability and death. With the development of next-generation gene-sequencing technology, the relationship between non-driver mutations and thrombotic risk factors has also attracted considerable attention. To analyze the risk factors of thrombosis in patients with essential thrombocythemia (ET) and polycythemia vera (PV), we retrospectively analyzed the clinical data of 125 MPN patients (75 ET and 50 PV) and performed a multivariate analysis of the risk factors of thrombosis using a Cox proportional risk model. Among the 125 patients, 35 (28.0%) had thrombotic events, and the incidence of thrombotic events was 21.3% and 38.0% in ET and PV patients, respectively. In ET patients, the multivariate analysis showed that a TET2 mutation and history of remote thrombosis were independent risk factors for thrombosis in ET patients, with an HR of 4.1 (95% CI: 1.40-12.01; p = 0.01) for TET2 mutation and 6.89 (95% CI: 1.45-32.68; p = 0.015) for a history of remote thrombosis. In PV patients, the multivariate analysis presented the neutrophil-to-lymphocyte ratio (NLR) (HR: 4.77, 95% CI: 1.33-17.16; p = 0.017) and a history of remote thrombosis (HR: 1.67, 95% CI: 1.03-1.32; p = 0.014) as independent risk factors for thrombosis, with no significant change in the risk of thrombosis in patients with TET2 mutations. A further analysis of the clinical characteristics and coagulation occurring in ET patients with a TET2 mutation revealed that the values of age and D-dimer were significantly higher and antithrombin III was significantly lower in TET2-mutated ET patients compared to TET2-unmutated patients. In summary, TET2 mutation may be more valuable in predicting thrombosis in ET patients than in PV patients. ET patients with a TET2 mutation are older and present differences in coagulation compared to TET2-unmutated patients.

Prediction of thrombosis in post-polycythemia vera and post-essential thrombocythemia myelofibrosis: a study on 1258 patients

Patients with Philadelphia-negative myeloproliferative neoplasms are at high risk of thrombotic events (TEs). Predisposing factors have been identified in essential thrombocythemia (ET), polycythemia vera (PV) and primary myelofibrosis (primary MF, PMF), while yet not recognized in post PV/ET-MF (known as secondary MF, SMF). Within the 1258 SMF of the MYSEC (MYelofibrosis SECondary to PV and ET) dataset, 135 (10.7%) developed a TE at a median follow-up of 3.5 years (range, 1-21.4), with an incidence of 2.3% patients per year. Venous events accounted for two-thirds of the total. Cox multivariable analysis, supported by Fine-Gray models with death as competitive risk, showed that being on cytoreductive therapy at time of SMF evolution is associated with an absolute risk reduction of thrombosis equal to 3.3% within 3 years. Considering individually cytoreductive therapies, univariate regression model found that both conventional cytoreduction, mainly hydroxyurea, (HR 0.41, 95% CI: 0.26-0.65, p = 0.0001) and JAK inhibitors, mostly ruxolitinib, (HR 0.50, 95% CI: 0.24-1.02, p = 0.05) were associated with fewer thrombosis. Our study informs treating physicians of a non-low incidence of TEs in post PV/ET-MF and of the potential protective role of cytoreductive therapy in terms of thrombotic events.

The Predictive Value of Neutrophil-Lymphocyte Ratio in Patients with Polycythemia Vera at the Time of Initial Diagnosis for Thrombotic Events

Objective

To investigate and discuss the predictive value of the neutrophil-to-lymphocyte ratio (NLR) in patients with polycythemia vera (PV) at the time of initial diagnosis, as well as its clinical significance in predicting the occurrence of thrombotic events and the progression of future thrombotic events during follow-ups, with the goal of providing a reference for the early identification of high-risk PV patients and the early intervention necessary to improve the prognosis of PV patients.

Method

A total of 170 patients diagnosed with PV for the first time were enrolled in this study. The risk factors affecting the occurrence and development of thrombotic events in these patients were statistically analyzed.

Results

NLR (P = 0.030), WBC count (P = 0.045), and history of previous thrombosis (P < 0.001) were independent risk factors for thrombotic events at the time of initial diagnosis. Age ≥ 60 years (P = 0.004), NLR (P = 0.025), history of previous thrombosis (P < 0.001), and fibrinogen (P = 0.042) were independent risk factors for the progression of future thrombotic events during follow-ups. The receiver operating characteristic curve (ROC curves) showed that NLR was more effective in predicting the progression of future thrombotic events than age ≥ 60 years, history of previous thrombosis, and fibrinogen. Kaplan-Meier survival analysis showed progression-free survival time of thrombotic events in the high NLR value group (NLR ≥ 4.713) (median survival time 22.033 months, 95% CI: 4.226-35.840), which was significantly lower compared to the low NLR value group (NLR < 4.713) (median overall survival time 66.000 months, 95% CI: 50.670-81.330); the observed difference was statistically significant (P < 0.001). The 60-month progression-free survival in the low NLR value group was 58.8%, while it was 32.8% in the high NLR value group.

Conclusion

Peripheral blood NLR levels in patients with PV resulted as an independent risk factor for the occurrence of thrombotic events at the time of initial diagnosis and for the progression of future thrombotic events during follow-ups. Peripheral blood NLR levels at the time of initial diagnosis and treatment had better diagnostic and predictive value for the progression of future thrombotic events in patients with PV than age ≥ 60 years, history of previous thrombosis, and fibrinogen.

Advances in Risk Stratification and Treatment of Polycythemia Vera and Essential Thrombocythemia

PURPOSE OF REVIEW

Estimating and modifying thrombotic risk is currently the mainstay of care for patients with polycythemia vera (PV) and essential thrombocythemia (ET). In recent years, however, increased attention has shifted towards quality of life and disease modification. In this review, we discuss recent advances in risk stratification, present updated results for ruxolitinib and interferon randomized clinical trials, discuss new approaches in antiplatelet and anticoagulant treatment, and summarize early phase trials of novel agents and emerging therapeutic concepts for the treatment of PV and ET.

RECENT FINDINGS

International collaborations and novel technologies, i.e., next-generation sequencing and machine learning techniques, have demonstrated excellent abilities to improve thrombotic risk stratification in PV and ET. Updated results from ruxolitinib and interferon randomized clinical trials have confirmed excellent efficacy and safety of these agents, both as first- and second-line treatments. Early trials of novel agents (histone deacetylase inhibitors, telomerase inhibitors, lysine-specific demethylase-1 inhibitors, human double-minute 2 inhibitors, and hepcidin mimetics) have shown encouraging efficacy and safety in blood count control, reduction of splenomegaly, and alleviation of disease-related symptoms. Finally, accumulating evidence suggested that direct oral anticoagulants may be a valid therapeutic alternative to warfarin for prolonged thromboprophylaxis. International collaborations ("big data") with the help of new technologies represent an exciting new approach to analyze rare outcomes in rare diseases, especially for identifying novel prognostic biomarkers in PV and ET. Randomized clinical trials are also needed to fully elucidate whether novel agents may establish new standards of care.