Abstract 4629: Long-Term Open Label Extension of the Prevention of Embolic and Thrombotic Events on Dabigatran in Atrial Fibrillation (PETRO- Ex study)
Dabigatran is an oral direct thrombin inhibitor (DTI), which has a rapid onset of action and can be given twice daily (b-i-d) without anticoagulation monitoring. To determine the long term safety and efficacy of dabigatran in patients with atrial fibrillation (AF). AF patients (n=502) from 53 centers in Denmark, the Netherlands, Sweden and the United States were enrolled in the PETRO study, a 12 week comparison between dabigatran (50, 150, and 300 mg b-i-d) and warfarin (INR 2–3). 361 dabigatran patients were rolled over into a long term extension trial (PETRO-Ex). The warfarin patient arm (n=70) was discontinued. All patients were initially maintained on the same dabigatran doses as in PETRO except the 50 mg b-i-d dose group who were switched to 150 mg once daily (qd). At entry, patients were 70 years old (mean age), 19% female, median AF duration of 4.2 years, and had a median of 3 stroke risk factors. Maximum and mean follow-up times were 51 and 29 months respectively. Due to higher frequency of major bleeding events in 300 mg b-i-d group and thromboembolic events in 150 mg qd group, they were switched to dabigatran 300 mg qd or 150 mg b-i-d groups.
PETRO and PETRO-Ex results: Events reported as absolute number of patients (per 100 patient-years) Thromboembolic event rates were lowest in the dabigatran 150 and 300 mg b-i-d groups. Major bleeding was most frequent in the 300 mg b-i-d group. No significant liver function abnormalities were noted in any of the dabigatran groups. The balance between stroke and bleeding risk supported dabigatran doses between 100 and 150 mg b-i-d for the ongoing phase 3 Randomized Evaluation of Longterm anticoagulation therapY (RELY) trial.