April 5th, 2011
MAGELLAN: Higher Bleeding Rates Cloud Rivaroxaban’s Effect in VTE Prevention in Acutely Ill Medical Patients
The novel anticoagulant rivaroxaban is successful in preventing venous thromboembolism (VTE) in acutely ill medical patients, but a high bleeding rate means the drug probably won’t be used for this indication. Alexander Cohen, presenting the results of the MAGELLAN trial at the ACC in New Orleans, explained by way of background that 50% to 70% of symptomatic thromboembolic events occur in nonsurgical patients.
Some 8,101 patients were randomized to either oral rivaroxaban for 35 days or subcutaneous enoxaparin for 10 days followed by placebo. Among the findings:
- At 10 days, the primary efficacy measure – a composite of asymptomatic proximal DVT, symptomatic DVT, symptomatic nonfatal PE, and VTE-related death – demonstrated that rivaroxaban was noninferior to enoxaparin. The primary outcome occurred in 2.7% of patients in each group (RR = 0.968; p=0.0025).
- At 35 days, rivaroxaban was significantly better than enoxaparin and placebo, as the composite endpoint was reached by 4.4% of patients on rivaroxaban versus 5.7% on enoxaparin and placebo (RR 0.771, p=0.0211).
However, there was a significantly increased risk for bleeding with rivaroxaban at both 10 and 35 days:
- At 10 days, clinically relevant bleeding occurred in 2.8% of rivaroxaban patients versus 1.2% of enoxaparin patients (RR=2.3; p< 0.0001).
- At 35 days, clinically relevant bleeding occurred in 4.1% of rivaroxaban patients versus 1.7% of enoxaparin patients (RR=2.5; p<0.0001).
At day 35, the net clinical benefit – defined as the composite of asymptomatic proximal DVT, symptomatic DVT, symptomatic nonfatal PE, VTE-related death, and treatment-emergent major plus non-major clinically relevant bleeding – occurred in 9.4% of the rivaroxaban group versus 7.8% of the enoxaparin/placebo group.
In response to a question after his presentation, Cohen explained that very few AF patients were enrolled in the trial because most of them would already have been receiving anticoagulation.
For more of our ACC.11 coverage of late-breaking clinical trials, interviews with the authors of the most important research, and blogs from our fellows on the most interesting presentations at the meeting, check out our Coverage Roundup.