Post-marketing surveillance on the long-term use of dabigatran in Japanese patients with nonvalvular atrial fibrillation: Preliminary report of the J-dabigatran surveillance.

BACKGROUND/AIM: A post-marketing surveillance (PMS) study is being conducted to investigate the safety and effectiveness of the long-term use of dabigatran etexilate (dabigatran) in Japanese patients with nonvalvular atrial fibrillation (NVAF). Results of an interim analysis of this prospective cohort study including patient characteristics and adverse drug reactions (ADRs) collected up to September 17, 2014 are reported here.

METHODS: Patients with NVAF who began to receive dabigatran for the first time from December 2011 to November 2013 were enrolled at 1042 study sites in Japan. Clinical parameters included patient characteristics, dabigatran dose strength, concomitant medications and outcome events. All outcome events were collected as serious and non-serious adverse events (AEs). ADRs were evaluated in this report. Pre-defined safety events of special interest for intensive survey were serious and non-serious outcome events such as myocardial infarction, as well as the total number of hemorrhage and gastrointestinal disorders.

RESULTS: A total of 6772 patients were registered. The safety analysis set included 6148 patients; mean age was 70.8±9.9 (SD) years: 2323 patients (37.8%) were aged 75 years or older. Males accounted for 66.8% of the patients. Mean CHADS2 score was 1.8±1.3; the CHADS2 score was 0 in 13.6%, 1 in 31.3%, 2 in 25.9%, 3 in 14.9%, and 4 to 6 in 11.1% of the patients. Of the 6148 patients, 1701 patients (27.7%) were switchers from warfarin and 4407 patients (71.7%) were non-switchers (OAC naïve patients). Treatment adherence was assessed for the first 3 months from the start of treatment for this analysis. Total 5656 patients (92.0%) reported taking dabigatran twice daily (bid) every day according to the label recommendation. During the follow up period [mean duration of follow up: 498±259 days (corresponding to 8386 patient-years)], pre-defined safety events of special interest for intensive survey (reported as serious ADRs) were: myocardial infarction, reported in 5 patients (0.06 per 100 patient-years); serious hemorrhage, reported in 46 patients (0.55 per 100 patient-years); and gastrointestinal disorders (non-hemorrhagic), reported in 11 patients (0.13 per 100 patient-years). Fifteen patients had ADRs with fatal outcome.

CONCLUSIONS: The interim findings from this 6148 patient PMS study further corroborate the favorable safety profile of dabigatran as demonstrated previously in controlled clinical trials. (ClinicalTrials.gov number, NCT01491178.).