Bayer and Johnson & Johnson have unveiled yet more data on its new antithrombotic Xarelto which the firms say demonstrate the drug’s superiority over Sanofi-Aventis’ Lovenox.

The companies has presented data from the RECORD4 study which involved 3,148 patients who received either one tablet/once-daily Xarelto (rivaroxaban) or a twice-daily injection of the present gold standard treatment Lovenox (enoxaparin) for 10 to 14 days after total knee replacement surgery. The data revealed that 6.9% of patients in the Xarelto group experienced venous thromboembolisms, compared with 10.1% on Lovenox and Bayer says this corresponds to a 31% relative risk reduction for its compound. The rate of major bleeding, the main safety measure of the trial, was numerically higher for Xarelto than Lovenox, but the difference was not statistically significant.

The Leverkusen-based firm noted that the previous RECORD1, 2 and 3 studies compared rivaroxaban against enoxaparin 40mg injected once-daily to reduce blood clots after major orthopaedic surgery. However, RECORD4 is the first trial to evaluate Xarelto against enoxaparin 30mg injected subcutaneously twice-daily, which is the US Food and Drug Administration-approved treatment regimen for Lovenox.

“The superior efficacy and similar adverse event profile of rivaroxaban demonstrated in RECORD4 are in line with the outstanding results of the earlier RECORD studies," said Alexander Turpie, professor of medicine, McMaster University, Canada and principal investigator for the programme, which has involved more than 12,500 patients. “The success of this trial strengthens my belief that direct Factor Xa inhibition with rivaroxaban has the potential to revolutionise the way we prevent the formation of dangerous blood clots,” he added. Prof Turpie’s enthusiasm was echoed by Frank Misselwitz, Bayer's head of cardiovascular clinical development, who claimed that “rivaroxaban has once again exceeded our expectations".

That Xarelto has proved superiority rather than just non-inferiority over Lovenox has impressed analysts and both Bayer and J&J shares enjoyed a rise. The firms have been waiting for the RECORD4 data before seeking approval in the USA which was filed in Europe for the prevention of VTE after major orthopaedic surgery of the lower limbs.

However that particular indication would be dwarfed in sales terms if rivaroxaban gets approved as a treatment to prevent stroke in atrial fibrillation patients. Bayer hopes to win approval for that indication in 2011, and that use would be long-term, ie daily, and more lucrative.