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

Raffaele Landolfi; Roberto Marchioli

doi:10.1055/s-2007-996124

Seminars in Thrombosis and Hemostasis, Table of Contents

Semin Thromb Hemost 1997; 23(5): 473-478
DOI: 10.1055/s-2007-996124

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.

Abstract

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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

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