Antiplatelet therapy versus observation in low-risk essential thrombocythemia with a CALR mutation

Alberto Alvarez-Larrán, Arturo Pereira, Paola Guglielmelli, Juan Carlos Hernández-Boluda, Eduardo Arellano-Rodrigo, Francisca Ferrer-Marín, Alimam Samah, Martin Griesshammer, Ana Kerguelen, Bjorn Andreasson, Carmen Burgaleta, Jiri Schwarz, Valentín García-Gutiérrez, Rosa Ayala, Pere Barba, María Teresa Gómez-Casares, Chiara Paoli, Beatrice Drexler, Sonja Zweegman, Mary F. McMullinJan Samuelsson, Claire Harrison, Francisco Cervantes, Alessandro M. Vannucchi, Carlos Besses

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The role of antiplatelet therapy as primary prophylaxis of thrombosis in low-risk essential thrombocythemia has not been studied in randomized clinical trials. We assessed the benefit/risk of low-dose aspirin in 433 patients with low-risk essential thrombocythemia (271 with a CALR mutation, 162 with a JAK2(V617F) mutation) who were on antiplatelet therapy or observation only. After a follow up of 2215 person-years free from cytoreduction, 25 thrombotic and 17 bleeding episodes were recorded. In CALR-mutated patients, antiplatelet therapy did not affect the risk of thrombosis but was associated with a higher incidence of bleeding (12.9 versus 1.8 episodes per 1000 patient-years, P=0.03). In JAK2(V617F)-mutated patients, low-dose aspirin was associated with a reduced incidence of venous thrombosis with no effect on the risk of bleeding. Coexistence of JAK2(V617F)-mutation and cardiovascular risk factors increased the risk of thrombosis, even after adjusting for treatment with low-dose aspirin (incidence rate ratio: 9.8; 95% confidence interval: 2.3-42.3; P=0.02). Time free from cytoreduction was significantly shorter in CALR-mutated patients with essential thrombocythemia than in JAK2(V617F)-mutated ones (median time 5 years and 9.8 years, respectively; P=0.0002) and cytoreduction was usually necessary to control extreme thrombocytosis. In conclusion, in patients with low-risk, CALR-mutated essential thrombocythemia, low-dose aspirin does not reduce the risk of thrombosis and may increase the risk of bleeding
Original languageEnglish
Pages (from-to)926-931
Issue number8
Publication statusPublished - Aug 2016

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