Purpose: Thromboprophylaxis is recommended for at least 10 days and up to 35 days following total hip replacement (THR). Rivaroxaban is an oral, direct Factor Xa inhibitor in advanced clinical development that showed promise in early clinical trials. The purpose of this randomized, double-blind, double-dummy, phase III study was to compare the efficacy and safety of oral rivaroxaban with subcutaneous enoxaparin for 5 weeks, to prevent venous thromboembolism (VTE) in patients undergoing primary THR.

Method: Patients received 10 mg rivaroxaban orally 6–8 hours after surgery and once daily thereafter, or 40 mg enoxaparin subcutaneously the evening before surgery (restarting 6–8 hours after surgery), and continued once daily. Thromboprophylaxis was administered for 35±4 days, and mandatory, bilateral venography was conducted the next day. The primary efficacy endpoint was the composite of any deep vein thrombosis (DVT), non-fatal pulmonary embolism (PE), and all-cause mortality. The primary efficacy analysis was a test for non-inferiority, followed by a test for superiority. Safety endpoints included major and non-major bleeding during the active treatment period.

Results: A total of 4541 patients were randomized to receive rivaroxaban or enoxaparin. Rivaroxaban significantly reduced the incidence of the composite of DVT, PE, and all-cause mortality compared with enoxaparin (1.1% vs 3.7%, respectively; p< 0.001; relative risk reduction [RRR] 70%). Rivaroxaban also significantly reduced the incidence of major VTE compared with enoxaparin (0.2% vs 2.0%, respectively; p< 0.001; RRR 88%). There were no significant differences in the incidence of major bleeding (0.3% vs 0.1%; p=0.178) or non-major bleeding (5.8% vs 5.8%; p=1.000) between rivaroxaban and enoxaparin, respectively. There was no evidence of cardiac or liver safety issues.

Conclusion: Oral, once-daily rivaroxaban was significantly more effective than subcutaneous, once-daily enoxaparin for extended thromboprophylaxis following THR. Rivaroxaban was not associated with an increased risk of bleeding and had a similar safety profile to enoxaparin. This trial demonstrated the efficacy and safety of a fixed, unmonitored dose of an oral, direct Factor Xa inhibitor – rivaroxaban – for extended thromboprophylaxis after THR.

Purpose: Rivaroxaban is a novel, oral, direct Factor Xa inhibitor in advanced clinical development for the prevention and treatment of thromboembolic disorders. RECORD3 was a phase III trial conducted to compare the efficacy and safety of oral rivaroxaban with subcutaneous enoxaparin for the prevention of venous thromboembolism (VTE) in patients undergoing total knee replacement (TKR).

Method: In this randomized, double-blind trial, patients received rivaroxaban 10 mg once daily (od), or enoxaparin 40 mg od. Enoxaparin was initiated the evening before surgery, and rivaroxaban 6–8 hours after surgery; therapy continued for 10–14 days. The primary efficacy outcome was the composite of any deep vein thrombosis (DVT), pulmonary embolism (PE), and all-cause mortality. Secondary efficacy outcomes included major VTE (the composite of proximal DVT, PE, and VTE-related death) and symptomatic VTE. Major bleeding was the primary safety outcome. Other safety outcomes included any on-treatment bleeding and hemorrhagic wound complications (the composite of excessive wound hematoma and surgical-site bleeding).

Results: A total of 2531 patients were randomized; 2459 were eligible for inclusion in the safety population and 1702 for the modified intention-to-treat population. The incidence of the primary efficacy outcome was significantly reduced with rivaroxaban compared with enoxaparin (relative risk reduction 49%, p< 0.001). Major VTE occurred in 1.0% and 2.6% of patients receiving rivaroxaban and enoxaparin, respectively (relative risk reduction 62%, p=0.016). The incidence of symptomatic VTE was significantly lower in the rivaroxaban group than in the enoxaparin group (p=0.005). Major bleeding rates were 0.6% and 0.5% in the rivaroxaban and enoxaparin groups, respectively, and rates of any on-treatment bleeding were 4.9% and 4.8%, respectively. The incidence of hemorrhagic wound complications was 2.1% in the rivaroxaban group and 1.9% in the enoxaparin group.

Conclusion: Rivaroxaban was significantly more effective than enoxaparin for thromboprophylaxis after TKR. Importantly, the incidence of bleeding was low and similar in both groups. This is the first trial to demonstrate the efficacy and safety of a fixed, unmonitored regimen of an oral, direct Factor Xa inhibitor – rivaroxaban – for thromboprophylaxis after TKR.

According to the 2004 ACCP guidelines on antithrombotic and thrombolytic therapy general extended prophylaxis with low molecular weight heparins, vitamin K antagonists, or fondaparinux is recommended after major orthopedic surgery. This recommendation is based on a number of placebo controlled, clinical studies using venographic screening for deep vein thrombosis (DVT), as a surrogate end-point for pulmonary embolism (PE), other vascular thrombotic events were not considered. In a recent meta-analysis on these studies the overall event rate of symptomatic venous thromboembolism 30–42 days after a joint arthroplasty was 2.7% DVT and 0.6 % PE in patients having short-term prophylaxis and it was significantly reduced by extended prophylaxis. Bleeding episodes were seen in 4% of cases having extension. Taking into consideration the risk benefit for the individual patient do these findings justify that extended prophylaxis is used on a general basis? To answer this question also compliance, adverse event profile, and cost of the prophylactic regimens have to be addressed. It would be very attractive to be able to individualize the duration of the prophylactic period by assessing the thrombotic potential of every patient in order to balance the risks and benefits of continued prophylaxis.