Bayer can start selling its novel one-tablet, once daily anticoagulant Xarelto very soon now that European regulators have approved the drug which is being touted as a blockbuster.

Specifically, the European Commission has granted marketing approval for Xarelto (rivaroxaban) for the prevention of venous blood clots in adults undergoing elective hip or knee replacement surgery. The green light was expected, seeing as how European Medicines Agency’s Committee for Medicinal Products in Human Use issued a positive opinion on the drug in July.

Bayer says that it will start launching the product in the European Union member states “very soon” and chief executive Werner Wenning said that “as Xarelto has the potential to become a blockbuster, its launch is an important milestone” for the Leverkusen-based firm. The approval is based on the RECORD clinical programme that included three Phase III trials of rivaroxaban involving 10,000 patients which demonstrated its superior efficacy in head-to-head comparisons with the current gold standard treatment, Sanofi-Aventis’ Lovenox (enoxaparin). The three trials also showed that Xarelto and Lovenox had comparable safety profiles including similar low rates of major bleeding.

The European approval comes just over a fortnight after Health Canada granted the first approval for Xarelto worldwide. The treatment, a Factor Xa inhibitor, was submitted to the US Food and Drug Administration in July and will be sold by Bayer’s partner Johnson & Johnson.

Though getting approval for Xarelto for the prevention of venous thromboembolic events after major orthopaedic surgery of the lower limbs is obviously a boost for Bayer, its prediction of global peak sales of 2 billion euros is dependent on getting to use the drug for stroke prevention in patients with atrial fibrillation. Bayer hopes to win approval for that indication in 2011.

As well as competing with Lovenox, Xarelto has some ground to make up on Boehringer Ingelheim's anticoagulant Pradaxa (dabigatran), an oral direct thrombin inhibitor which was approved in Europe in March for prevention of VTE after hip or knee replacement surgery.