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Essential thrombocythemia (ET) and polycythemia vera (PV) are myeloproliferative neoplasms (MPNs) characterized by an increased risk of developing venous and arterial thromboses and of evolution to myelofibrosis or acute leukemia (1). MPNs are recognized as a major cause of splanchnic vein thromboses (SVT), which include hepatic, splenic, portal and mesenteric vein thromboses (2). Patients with SVT are at an increased risk of developing bleeding events and arterial thrombotic events (3), as well as recurrent SVT and the use of anticoagulation and cytoreduction do not clearly modify this risk (3–5). Management of SVT in MPN patients remains a challenge and most therapeutic recommendations are based on retrospective analyses (6). Recently, De Stefano reported that hydroxyurea failed to prevent recurrent thromboses in the splanchnic vasculature in patients with a prior SVT (7). We conducted a prospective, open-label, multi-center phase II clinical trial of Pegylated Interferon Alfa-2a (PEG) in 20 subjects with SVT and an MPN, who represented a cohort of patients who participated in the Myeloproliferative Disorders - Research Consortium (MPD-RC) 111 trial (). MPD-RC 111 was a prospective study of patients with high-risk ET/PV who were resistant or intolerant to hydroxyurea (HU), but prior HU therapy was not a requirement for patients to enter the SVT cohort. Here we report the outcomes of the 20 SVT patients who were treated with PEG.

A total of 410 patients with blast phase myeloproliferative neoplasm (MPN-BP) were retrospectively reviewed: 248 from the Mayo Clinic and 162 from Italy. Median survival was 3.6 months, with no improvement over the last 15 years. Multivariable analysis performed on the Mayo cohort identified high risk karyotype, platelet count 65 years and transfusion need as independent risk factors for survival. Also in the Mayo cohort, intensive chemotherapy resulted in complete remission (CR) or CR with incomplete count recovery (CRi) rates of 35 and 24%, respectively; treatment-specified 3-year/5-year survival rates were 32/10% for patients receiving allogeneic stem cell transplant (AlloSCT) (n = 24), 19/13% for patients achieving CR/CRi but were not transplanted (n = 24), and 1/1% in the absence of both AlloSCT and CR/CRi (n = 200) (p

The optimal duration of treatment with vitamin K antagonists (VKA) after venous thromboembolism (VTE) in patients with Philadelphia-negative myeloproliferative neoplasms (MPNs) is uncertain. To tackle this issue, we retrospectively studied 206 patients with MPN-related VTE (deep venous thrombosis of the legs and/or pulmonary embolism). After this index event, we recorded over 695 pt-years 45 recurrences, venous in 36 cases, with an incidence rate (IR) of 6.5 per 100 pt-years (95% confidence interval (CI): 4.9-8.6). One hundred fifty-five patients received VKA; the IR of recurrent thrombosis per 100 pt-years was 4.7 (95% CI: 2.8-7.3) on VKA and 8.9 (95% CI: 5.7-13.2) off VKA (P=0.03). In patients receiving VKA, the IR of recurrent thrombosis per 100 pt-years was 5.3 (95% CI: 3.2-8.4) among 108 patients on long-term VKA and 12.8 (95% CI: 7.3-20.7) after discontinuation among the 47 who ceased treatment (P=0.008), with a doubled risk of recurrence after stopping VKA (hazard ratio: 2.21, 95% CI: 1.19-5.30). The IR of major bleeding per 100 pt-years was 2.4 (95%: CI: 1.1-4.5) on VKA and 0.7 (95% CI: 0.08-2.5) off VKA (P=0.08). In conclusion, in MPN patients with VTE recurrent thrombosis is significantly reduced by VKA and caution should be adopted in discontinuation; however, the incidence of recurrence on treatment remains high, calling for clinical trials aimed to improve prophylaxis in this setting.

CALR mutation, MPL mutation and triple negativity identify patients with the lowest vascular risk in primary myelofibrosis