[SPORTIF III and V trials: a major breakthrough for long-term oral anticoagulation]

Ximelagatran (Exanta, AstraZeneca), which is still investigational, is the first of a new category of direct inhibitors of thrombin which can be administered orally. SPORTIF III and V trials are both randomized studies; the first is open-label; the second, double-blind. They involved patients aged 18 or over with a non-valvular atrial fibrillation and, at least, one additional risk factor fot stroke (St) or systemic embolism (SE). They compared traditional warfarin anticoagulation (INR = 2-3) with fixed dose ximelagatran (36 mg twice daily) for the prevention of St/SE. These studies are non-inferiority trials. In the intention-to-treat analysis, SPORTIF III (3,407 patients [1,704 on on ximelagatran and 1,703 on warfarin]; mean follow-up of 17.4 months) observed 40 cases of St/SE in the ximelagatran group and 56 in the warfarin group. These data demonstrated the non-inferiority of ximelagatran. In addition, the per protocol analysis showed a superiority of ximelagatran (0.018). SPORTIF V (3,992 patients; mean follow-up of 20 months) observed 88 cases of St/SE. The incidence of these events was similar in both treatment-groups with an absolute difference no greater than 0.5%/yr. The non-inferiority of ximelagatran was thus confirmed. In both studies, bleedings were observed on both therapies with a slight trend in favor of ximelagatran. Additionally, some 6% of patients treated by ximelagatran experienced an increase to greater than three times the upper limit of normal of the liver enzyme alanine aminotransferase (ALT), compared to 0.7-0.8% in the warfarin group. Nearly all enzyme rises occurred during the first six months of therapy and decreased with or without drug discontinuation. The potential breakthrough that these data represent for oral anticoagulation is briefly outlined.