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Semin Thromb Hemost 1997; 23(5): 473-478
DOI: 10.1055/s-2007-996124
Copyright © 1997 by Thieme Medical Publishers, Inc.

European Collaboration on Low-dose Aspirin in Polycythemia Vera (ECLAP): A Randomized Trial

Raffaele Landolfi* , Roberto Marchioli† (on behalf of the ECLAP investigators)
  • From the *Istituto di Semeiotica Medica Universitá Cattolica del Sacro Cuore, Roma, and
  • †Dipartimento di Farmacologia Clinica ed Epidemiologia Consorzio Mario Negri Sud, Istituto di Ricerche Farmacologiche Mario Negri. S.M. Imbaro, Chieti, Italy.
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Publication History

Publication Date:
08 February 2008 (online)

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Abstract

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 ≤ 45% in subjects aged ≤50, and hematocrit <45% as well as platelet count <400 × 109/L in patients aged >50. Randomization will be stratified by participating center.

The study is funded by the European Union BIOMED 2 program.

Keywords:

Polycythemia vera - aspirin - lowdose ASA - thrombosis - ECLAP trial