Antifactor Xa Drug Helps Fights Pulmonary Embolism with Less Bleeding

Researchers at the University of Amsterdam Academic Medical Center (AMC; The Netherlands) conducted a randomized, open-label, event-driven study involving 4,832 patients who had acute symptomatic PE with or without deep-vein thrombosis (DVT). The researchers compared treatment with rivaroxaban (15 mg twice daily for 3 weeks, followed by 20 mg once daily) with standard therapy with enoxaparin followed by an adjusted-dose vitamin K antagonist for 3, 6, or 12 months. The primary efficacy outcome was symptomatic recurrent venous thromboembolism. The principal safety outcome was major or clinically relevant nonmajor bleeding.

The results showed that rivaroxaban was noninferior to standard therapy for the primary efficacy outcome, with 50 events in the rivaroxaban group (2.1%) versus 44 events in the standard-therapy group (1.8%). The principal safety outcome occurred in 10.3% of patients in the rivaroxaban group and 11.4% of those in the standard-therapy group. Major bleeding, however, was observed in only 26 patients (1.1%) in the rivaroxaban group, compared to 52 patients (2.2%) in the standard-therapy group; rates of other adverse events were similar in the two groups. The study was published in the April 5, 2012, issue of the New England Journal of Medicine (NEJM).

“A fixed-dose regimen of rivaroxaban alone was noninferior to standard therapy for the initial and long-term treatment of pulmonary embolism, and had a potentially improved benefit-risk profile,” concluded lead author Harry Büller, MD, and colleagues.

The most compelling advantage in giving rivaroxaban at the same dose in all patients, according to the researchers, is that there is no need for laboratory monitoring of international normalized ratio (INR), a tremendous convenience factor due to the fact that efficacy and safety appeared similar across age, sex, PE severity, and obesity and renal function status groups.

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University of Amsterdam Academic Medical Center