European Collaboration on Low-dose Aspirin in Polycythemia Vera (ECLAP): a randomized trial.
Thrombotic complications characterize the clinical course of polycythemia vera (PV) and represent the main cause of morbidity and mortality. However, uncertainty still exists as to the benefit/risk ratio of aspirin prophylaxis in this setting. In vivo platelet biosynthesis of thromboxane A2 is enhanced and can be suppressed by low-dose aspirin in PV, thus providing a rationale for assessing the efficacy and safety of a low-dose aspirin regimen in these patients. The Gruppo Italiano Studio Policitemia Vera has recently performed a pilot study on 112 patients randomized to receive aspirin, 40 mg daily, or placebo and followed for 16 +/- 6 months (mean +/- SD). This study showed that low-dose aspirin is well tolerated in PV patients, and that a large-scale efficacy trial is feasible in this setting. In this article we report the protocol of the European Collaboration on Low-dose Aspirin in Polycythemia Vera (ECLAP) study, which is a randomized trial designed to assess the risk/benefit ratio of low-dose aspirin in PV. To estimate the size and the follow-up duration required for the ECLAP trial, a retrospective analysis of the clinical epidemiology of a large PV population has recently been completed by the Gruppo Italiano Studio Policitemia Vera. On this basis, approximately 3500 patients will be enrolled in the ECLAP study with a follow-up of 3 to 4 years. The uncertainty principle will be used as the main eligibility criterion: Polycythemic patients of any age, having no clear indication for or contraindication to aspirin treatment, will be randomized in a double-blind fashion to receive oral aspirin (100 mg daily) or placebo. According to current therapeutic recommendations, the basic treatment of randomized patients should be aimed at maintaining the hematocrit value < or = 45% in subjects aged < or = 50, and hematocrit < 45% as well as platelet count < 400 x 10(9)/L in patients aged > 50. Randomization will be stratified by participating center. The study is funded by the European Union BIOMED 2 program.
Landolfi
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Istituto di Semeiotica Medica Università Cattolica del Sacro Cuore, Roma, Italy.
Marchioli
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D001241:Aspirin / Q000627:therapeutic use*; D004305:Dose-Response Relationship, Drug; D005060:Europe; D005240:Feasibility Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D010865:Pilot Projects; D010975:Platelet Aggregation Inhibitors / Q000627:therapeutic use*; D011087:Polycythemia Vera / Q000150:complications*; D013927:Thrombosis / Q000517:prevention & control*; D016896:Treatment Outcome
D010975:Platelet Aggregation Inhibitors; D001241:Aspirin