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Patients with essential thrombocythemia (ET) are treated with once-daily low-dose aspirin to prevent thrombosis, but their accelerated platelet turnover shortens the antiplatelet effect. The short-term Aspirin Regimens in EsSential Thrombocythemia trial showed that twice-daily aspirin dosing restores persistent platelet thromboxane (TX) inhibition. However, the long-term pharmacodynamic efficacy, safety and tolerability of twice-daily aspirin remain untested. We performed a multicenter, randomized, open-label, blinded-endpoint, phase-2 trial in which 242 patients with ET were randomized to 100 mg aspirin twice- or once-daily and followed for 20 months. The primary endpoint was the persistence of low serum TXB 2 , a surrogate biomarker of antithrombotic efficacy. Secondary endpoints were major and clinically relevant non-major bleedings, serious vascular events, symptom burden assessed by validated questionnaires, and in vivo platelet activation. Serum TXB 2 was consistently lower in the twice-daily versus once-daily regimen on 10 study visits over 20 months: median 3.9 ng/mL versus 19.2 ng/mL, respectively; p < .001; 80% median reduction; 95% CI, 74%-85%. No major bleeding occurred. Clinically relevant non-major bleedings were non-significantly higher (6.6% vs. 1.7%), and major thromboses lower (0.8% vs. 2.5%) in the twice-daily versus once-daily group. Patients on the twice-daily regimen had significantly lower frequencies of disease-specific symptoms and severe hand and foot microvascular pain. Upper gastrointestinal pain was comparable in the two arms. In vivo platelet activation was significantly reduced by the twice-daily regimen. In patients with ET, twice-daily was persistently superior to once-daily low-dose aspirin in suppressing thromboxane biosynthesis and reducing symptom burden, with no detectable excess of bleeding and gastrointestinal discomfort., (© 2024 The Author(s). American Journal of Hematology published by Wiley Periodicals LLC.)

Competing Interests: Conflicts of interest The authors declare no conflicts of interest.

Competing Interests: Declaration of Competing Interest None.

Opinion Statement: Prophylaxis and treatment of thrombosis in leukemic patients still represent a major challenge with several clinical questions yet to be solved. Indeed, the paucity of evidence makes the management of venous thromboembolic events difficult and not uniform. Due to thrombocytopenia, patients with acute myeloid leukemia (AML) are underrepresented in trials investigating prophylaxis and treatment of thrombosis in cancer, and prospective data are lacking. Likewise, the therapeutic approach with anti-coagulants in leukemic patients is inferred from guidelines originally developed in the solid cancer setting and clear recommendations in the thrombocytopenic population are limited. Importantly, the discrimination of patients at high risk of bleeding from those with a predominant risk of thrombosis remains extremely difficult with no predictive score validated so far. Thus, the management of thrombosis often relies on clinician experience, and it is tailored to the individual patient, constantly balancing thrombotic and hemorrhagic risks. Who would benefit from primary prophylaxis and how a thrombotic event should be appropriately treated are some of the unanswered questions that the future guidelines and trials should address. Moreover, a greater effort should be made to identify robust predictive factors able to guide clinicians in the management of this potential serious complication for AML patients., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Objectives: Erythropoiesis-stimulating agents (ESA) have an established role in treating anemia in hematological malignancies. However, their role, particularly biosimilar ESA (B-ESA), in myelofibrosis (MF) is not well established., Methods: This study retrospectively collected data on 96 MF patients treated with B-ESA (alpha/zeta) for the management of anemia to assess safety, efficacy (anemia response [AR]), and survival., Results: Seventy-seven patients (80%) obtained AR. The median time to AR was 2.5 months. In multivariate analysis, significant predictive factors of AR were transfusion independency (p = .006) and ferritin levels <200 ng/ml (p = .009) at baseline. After a median follow-up of 43.8 months from diagnosis, 38 patients (39%) died, 11 (28.9%) from leukemic evolution. Only two patients (2.5%) stopped B-ESA for toxicity. The 24-month survival was significantly affected by response to B-ESA (70.8% in AR vs. 55.3% in non-responder patients, p = .016). In multivariate analysis, age ≤ 70 years (p = .029) and Hb > 8.5 g/dl (p = .047) at baseline were significantly associated with improved survival, with a trend for longer survival in AR patients (p = .06)., Conclusions: B-ESA seems to be an effective and well-tolerated option for anemia treatment in the MF setting. This strategy deserves further clinical investigation., (© 2022 The Authors. European Journal of Haematology published by John Wiley & Sons Ltd.)

Essential thrombocythemia (ET) is a myeloproliferative neoplasm characterized by enhanced platelet production and thrombotic complications. The inhibition of platelet cyclooxygenase (COX) activity by the standard once-daily aspirin is mostly incomplete due to accelerated thrombopoiesis. The phase II Aspirin Regimens in EsSential thrombocythemia (ARES) trial has recently compared the efficacy of once- vs. twice- or three-times daily low-dose aspirin in inhibiting platelet thromboxane (TX) A 2 production, as reflected by serum (s) TXB 2 measurements. The present substudy characterized the determinants of the highly variable response to the standard aspirin 100 mg once-daily regimen in fully compliant patients with ET and the effects of the experimental dosing regimens on response variability. By multivariable analysis, the platelet count (directly) and cytoreductive treatment (inversely) were significantly associated with sTXB 2 values in 218 patients with ET. However, the platelet count positively correlated with sTXB 2 in patients not being treated with cytoreductive drugs (ρ = 0.51, P < 0.01, n = 84), but not in patients on cytoreduction. Patients in the lowest sTXB 2 quartile were older, more often on cytoreductive drugs, had lower platelet count and Janus-Associated Kinase2 (JAK2)-V617F allele frequency as compared with patients in the upper sTXB 2 quartiles. After 2 weeks of a twice- or 3-times daily aspirin regimen, the association between the platelet count and sTXB 2 became similar in cytoreduced and non-cytoreduced patients. In conclusion, the platelet count appears the strongest determinant of TXA 2 inhibition by once-daily low-dose aspirin in ET, with different patterns depending of cytoreductive treatment. More frequent aspirin dosing restores adequate platelet inhibition and reduces interindividual variability, independently of cytoreduction., (© 2021 The Authors. Clinical Pharmacology & Therapeutics published by Wiley Periodicals LLC on behalf of American Society for Clinical Pharmacology and Therapeutics.)

The frequency of thrombosis in AML has been evaluated only in a few studies and no validated predictive model is currently available. Recently, DIC score was shown to identify patients at higher thrombotic risk. We aimed to evaluate the frequency of thromboembolism in AML patients treated with intensive chemotherapy and to assess the ability of genetic and clinical factors to predict the thrombotic risk. We performed a retrospective observational study including 222 newly diagnosed adult AML (210) and high-risk MDS (12), treated with intensive chemotherapy between January 2013 and February 2020. With a median follow-up of 44 months, we observed 50 thrombotic events (90% were venous, VTE). The prevalence of thrombosis was 22.1% and the 6-months cumulative incidence of thrombosis was 10%. The median time to thrombosis was 84 days and 52% of the events occurred within 100 days from AML diagnosis. Khorana and DIC score failed to stratify patients according to their thrombotic risk. Only history of a thrombotic event (p = 0.043), particularly VTE (p = 0.0053), platelet count above 100 × 10 9 /L at diagnosis (p = 0.036) and active smoking (p = 0.025) significantly and independently increased the risk of thrombosis, the latter particularly of arterial events. AML genetic profile did not affect thrombosis occurrence. Results were confirmed considering only thromboses occurring within day 100 from diagnosis. DIC score at diagnosis, but not thrombosis, was independently associated with reduced survival (p = 0.004). Previous VTE, platelet count above 100 × 10 9 /L and active smoking were the only factors associate with increased thrombotic risk in AML patients treated intensively, but further studies are needed to validate these results., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Introduction Chronic myeloproliferative neoplasm (MPNs) are clonal malignant bone marrow (BM) diseases, arising from a hematopoietic stem cell. All therapies for these neoplasms have peculiar effects on the bone marrow, but little evidence has been described in the literature. Areas covered This review examines BM morphological changes following the main treatments in Philadelphia-negative MPNs. Hydroxyurea can reduce the cellularity of the erythroid and megakaryocyte lineages but has minimal impact on fibrotic evolution. There is general agreement on its dysplastic effects, with a high incidence of acute myeloid leukemia and myelodysplastic syndrome. Interferon treatment can reduce or normalize BM cellularity, improve erythropoiesis, and reduce the number and atypicality of megakaryocytes. Most data describe reduction or complete resolution of marrow fibrosis; dysplastic effects are not reported. Anagrelide may induce an increase in the number of BM megakaryocytes, especially immature megakaryocytes or precursors, and a worsening of marrow fibrosis or increased transformation of essential thrombocythemia into myelofibrosis. Ruxolitinib can improve or stabilize BM fibrosis and reduces the frequency and dense clustering of megakaryocytes. Expert opinion Since previous therapy can modify BM features, it is essential to obtain information on previous or current therapies and to collect complete clinical information.

Myeloproliferative neoplasms (MPNs) are clonal stem cell disorders characterized collectively by clonal proliferation of myeloid cells with variable morphologic maturity and hematopoietic efficiency. Although the natural history of these neoplasms can be measured sometimes in decades more than years, the cytogenetics analysis can offer useful information regarding the prognosis. Cytogenetics has a well-established prognostic role in acute leukemias and in myelodysplastic syndromes, where it drives the clinical decisions. NGS techniques can find adverse mutations with clear prognostic value and are currently included in the prognostic evaluation of MPNs in scores such as MIPSS, GIPSS, MIPSS-PV, and MIPSS-ET. We suggest that cytogenetics (considering its availability and relative cost) has a role regarding prognostic and therapeutic decisions.

Essential thrombocythemia (ET) is characterized by abnormal megakaryopoiesis and enhanced thrombotic risk. Once-daily low-dose aspirin is the recommended antithrombotic regimen, but accelerated platelet generation may reduce the duration of platelet cyclooxygenase-1 (COX-1) inhibition. We performed a multicenter double-blind trial to investigate the efficacy of 3 aspirin regimens in optimizing platelet COX-1 inhibition while preserving COX-2-dependent vascular thromboresistance. Patients on chronic once-daily low-dose aspirin (n = 245) were randomized (1:1:1) to receive 100 mg of aspirin 1, 2, or 3 times daily for 2 weeks. Serum thromboxane B2 (sTXB2), a validated biomarker of platelet COX-1 activity, and urinary prostacyclin metabolite (PGIM) excretion were measured at randomization and after 2 weeks, as primary surrogate end points of efficacy and safety, respectively. Urinary TX metabolite (TXM) excretion, gastrointestinal tolerance, and ET-related symptoms were also investigated. Evaluable patients assigned to the twice-daily and thrice-daily regimens showed substantially reduced interindividual variability and lower median (interquartile range) values for sTXB2 (ng/mL) compared with the once-daily arm: 4 (2.1-6.7; n = 79), 2.5 (1.4-5.65, n = 79), and 19.3 (9.7-40; n = 85), respectively. Urinary PGIM was comparable in the 3 arms. Urinary TXM was reduced by 35% in both experimental arms. Patients in the thrice-daily arm reported a higher abdominal discomfort score. In conclusion, the currently recommended aspirin regimen of 75 to 100 once daily for cardiovascular prophylaxis appears to be largely inadequate in reducing platelet activation in the vast majority of patients with ET. The antiplatelet response to low-dose aspirin can be markedly improved by shortening the dosing interval to 12 hours, with no improvement with further reductions (EudraCT 2016-002885-30)., (© 2020 by The American Society of Hematology.)

Erythropoiesis-stimulating agents (ESAs) were combined with ruxolitinib in 59 anaemic myelofibrosis patients (93% with Dynamic International Prognostic Scoring System [DIPSS] intermediate-2/high risk; 52·5% transfusion-dependent). Anaemia response (AR) rate was 54% and 76% of patients responded at 5 years. A further 15% displayed minor improvement in anaemia and 78% of patients reduced spleen size. Endogenous erythropoietin levels <125 u/l correlated with a higher AR rate (63% vs. 20%, P = 0·008). No thrombotic events or other toxicities occurred. Overall survival was 62% at 4 years, influenced by DIPSS and transfusion dependency. ESAs seem effective in improving anaemia in ruxruxolitinib-treated myelofibrosis patients., (© 2018 British Society for Haematology and John Wiley & Sons Ltd.)

Once-daily (od), low-dose aspirin (75-100 mg) is recommended to reduce the thrombotic risk of patients with essential thrombocytemia (ET). This practice is based on data extrapolated from other high-risk patients and an aspirin trial in polycythemia vera, with the assumption of similar aspirin pharmacodynamics in the two settings. However, the pharmacodynamics of low-dose aspirin is impaired in ET, reflecting accelerated renewal of platelet cyclooxygenase (COX)-1. ARES is a parallel-arm, placebo-controlled, randomized, dose-finding, phase II trial enrolling 300 ET patients to address two main questions. First, whether twice or three times 100 mg aspirin daily dosing is superior to the standard od regimen in inhibiting platelet thromboxane (TX)A 2 production, without inhibiting vascular prostacyclin biosynthesis. Second, whether long-term persistence of superior biochemical efficacy can be safely maintained with multiple vs. single dosing aspirin regimen. Considering that the primary study end point is serum TXB 2 , a surrogate biomarker of clinical efficacy, a preliminary exercise of reproducibility and validation of this biomarker across all the 11 participating centers was implemented. The results of this preliminary phase demonstrate the importance of controlling reproducibility of biomarkers in multicenter trials and the feasibility of using serum TXB 2 as a reliable end point for dose-finding studies of novel aspirin regimens.