UPDATE: Bayer's rivaroxaban shows superiority to enoxaparin in Ph III

Data presented at the International Society for Thrombosis and Hematology in Geneva, Switzerland, from the first Phase III clinical study with German drugs major Bayer Healthcare's oral anticoagulant Xarelto (rivaroxaban) indicate that the drug is significantly more effective than enoxaparin (Sanofi-Aventis' Lovenox) in the prevention of venous thromboembolism, 9.6% versus 18.9%, in patients undergoing total knee replacement. The compound is being jointly with US drug major Johnson & Johnson.

Patients in the RECORD3 (REgulation of Coagulation in major Orthopedic surgery reducing the Risk of DVT and PE) study who were treated with rivaroxaban demonstrated a 49% relative risk reduction (p<0.001) of the composite primary endpoint of deep vein thrombosis, non-fatal pulmonary embolism and all-cause mortality compared to those treated with enoxaparin. An even greater (62%) reduction of risk (p=0.01) of developing major VTE (the composite of proximal DVT, non-fatal PE and VTE-related death), the secondary endpoint of the trial, was observed in the patients treated with rivaroxaban. Importantly, rivaroxaban also demonstrated a similarly low rate of major bleeding compared to enoxaparin (0.6% and 0.5%, respectively).

Commenting on the results, analysts at Lehman Brothers noted that, at last month's analysts' meeting, Bayer management were notably upbeat about the data to be presented for this trial and the abstract suggests that this confidence was justified with the VTE rate on rivaroxaban notably lower than the Lovenox arm (the bleeding rates seen were similar). This trial (RECORD 3) is in the acute setting and there are another three Phase III studies still to report in this acute setting (all expected by year end). Although this data is encouraging, the key commercial indication for this product will be in the chronic use indications, says the analysts. Phase III data in the latter indication is not due to report until 2010.