AstraZeneca has decided to withdraw the anticoagulant Exanta (melagatran/ximelagatran) from the market and terminate its development, after the new safety data uncovered severe liver injury. Two ongoing Exanta clinical trials will be discontinued and Exanta-treated patients switched to other treatments.

The company's clinical trials had recently indicated that an observation of rapid onset of signs and symptoms in the weeks following the end of the 35 days treatment. This specific observation has not previously been made in relation to Exanta and indicates that regular liver function monitoring may not mitigate the possible risk, states the AstraZeneca release.

AstraZeneca estimates that approximately 400 patients are currently being prescribed the drug for short-term prevention of venous thromboembolism (VTE) following orthopaedic surgery (OS).

AstraZeneca has informed regulatory authorities of its decision to withdraw Exanta and is now communicating with all prescribers and healthcare professionals to advise them that no new patients should be started on Exanta.

David Brennan, chief executive officer, AstraZeneca PLC said, "We have decided to take this precautionary action in the interests of patient safety. There are a number of alternative options for short-term post-operative anticoagulation following orthopaedic surgery. We would like to recognise the involvement of doctors, patients and scientists and their commitment to the development of Exanta over the past years."

Exanta is dispensed only in Europe. The drug failed to receive approval from the US Food and Drug Administration in late 2004 because of concerns about its effect on the liver.