The Japanese Aggrenox (Extended-Release Dipyridamole plus Aspirin) Stroke Prevention versus Aspirin Programme (JASAP) Study: A Randomized, Double-Blind, Controlled Trial

Abstract

Background: Despite improvements in treatment, stroke still carries a high death toll and disability in Asia. Extended-release dipyridamole (ER-DP) plus acetylsalicylic acid (ASA) has consistently been shown to be superior over conventional platelet inhibition by ASA. ER-DP plus ASA is well established in the secondary prevention of stroke in a lot of countries including the USA and Europe. DP has an established benefit in the treatment of heart disease in Japan; however, for the prevention of stroke, the fixed-dose combination of ER-DP plus ASA has only been investigated in a small number of patients in Japan. Methods: The aim of this double-blind, randomized clinical trial was to investigate the efficacy and safety of ER-DP plus ASA versus 81 mg ASA over 1 year. The primary end point of this study was the event rate of recurrent ischemic stroke (fatal or nonfatal) using the Kaplan-Meier method and Cox regression analysis. Results: Of the 1,294 enrolled patients, the primary end point was analyzed in 652 patients in the ER-DP plus ASA group and 639 in the ASA group. The incidence of ischemic stroke was 6.9% for ER-DP plus ASA and 5.0% for ASA with a hazard ratio of 1.47 (95% confidence interval 0.93–2.31) for the primary end point. The ASA treatment group was found to have a lower than expected yearly event rate, compared to other studies in Japanese stroke patients. Noninferiority of ER-DP plus ASA versus ASA could not be shown. The risks of major bleeding events and intracranial hemorrhage were found to be similar between the treatment arms. There were 4 deaths (0.6%) in the ER-DP plus ASA group and 10 (1.6%) in the ASA group. Conclusions: The results of the study are inconclusive. Noninferiority of ER-DP plus ASA versus ASA could not be established, a difference between treatments could not be shown for the primary end point. Possible reasons for this result include a small sample size, low event rates and too short a treatment duration (ClinicalTrials. gov number, NCT00311402).