The data presented at the European Society of Cardiology (ESC) by Keith Fox, co-chair of the ROCKET AF Executive Steering Committee and professor of Cardiology at the University of Edinburgh, show that these patients respond favourably to a reduced 15mg daily dose of Bayer’s Xarelto (rivaroxaban) compared with warfarin, an outcome consistent with those with preserved renal function who were given 20mg of rivaroxaban daily.
The use of traditional anticoagulants such as vitamin K antagonists (VKAs) including warfarin in patients with AF and renal impairment can be challenging for physicians, due to the need for regular dosing changes to avoid complications such as over-anticoagulation which can lead to major bleeding events.
In this sub-group of 2,950 patients (representing 21% of the overall study population), rivaroxaban showed comparable safety outcomes to warfarin; importantly, rates of critical organ bleeding (HR 0.55; 95% CI 0.30-1.00) and fatal bleeding (HR 0.55; 95% CI 0.32-0.93) were lower with rivaroxaban, consistent with results seen by investigators in the ROCKET AF primary analysis. Gastrointestinal bleeding was more frequent in the rivaroxaban group compared to warfarin (4.1% vs. 2.6%, p=0.02). There were no significant differences in other bleeding sites between rivaroxaban 15mg and dose-adjusted warfarin.
The primary efficacy endpoint rate (incidence of stroke or non-central nervous systemic embolism) was 2.32 events per 100 patient years with rivaroxaban 15mg per day, compared with 2.77 events per 100 patient years with dose-adjusted warfarin in the per-protocol population (HR 0.84; 95% CI 0.57-1.23, p value for interaction=0.76).
Together, these efficacy and safety findings confirm the primary results of ROCKET AF study published by the New England Journal of Medicine (NEJM) in August 2011.
The mean age of enrolled patients in ROCKET AF with moderate renal dysfunction was 79, older than the mean age of 73 in patients without renal dysfunction who received a higher 20mg dose of rivaroxaban.
“The findings of this analysis demonstrate that rivaroxaban has the ability to prevent stroke in patients with moderate renal insufficiency, without elevating the risk of critical bleeding events such as intra-cranial haemorrhage,” said Fox. “The average age of 79 in this group is also important, because patients with non-valvular AF tend to be of older age, and can have a higher risk of stroke due to the increased prevalence of conditions like congestive heart failure, hypertension, diabetes and prior stroke.”
Rivaroxaban is currently licensed in the UK for the prevention of venous thromboembolism (VTE) in patients undergoing elective total hip or knee replacement surgery, and is not licensed for the prevention of stroke and non-CNS systemic embolism in patients with non-valvular AF.