GlaxoSmithKline’s plans to get its anticoagulant drug Arixtra approved in a new indication have been set back somewhat by the US Food and Drug Administration’s request for more information.

The drug major has only received an approvable letter from the agency for Arixtra (fondaparinux sodium) for the treatment of patients with acute coronary syndromes, including unstable angina and non-ST segment elevation myocardial infarction (STEMI) after a six-month priority review. GSK gave no details as to what the letter was requesting and limited itself to saying that will continue to work with the FDA to provide the additional information.

The data that GSK has provided up to now comes principally from the OASIS 5 and OASIS 6 clinical trials and the latter, carried out in 12,000 patients with STEMI - found that Arixtra reduced death or recurrent heart attack by 14% and all cause mortality by 13% compared to unfractionated heparin or placebo.

Arixtra, an oral Factor Xa inhibitor, is already approved in the USA to treat patients undergoing surgery who are at risk of deep vein thrombosis and pulmonary embolism. Approval of the new indications would likely boost sales of the drug, which came in at just £13 million for the third quarter of 2006 and may help the drug make some inroads on the market leader Sanofi-Aventis' Lovenox (enoxaparin).

GSK takes Ranbaxy to court over generic Valtrex

Meantime GSK has moved quickly after being informed by Ranbaxy Laboratories that it intends to market a generic version of the herpes drug Valtrex (valaciclovir) and said will ask a US court for a preliminary injunction to prevent the Indian drugmaker from launching. Ranbaxy has just won approval from the FDA to market the drug, which is a big earner for GSK. It had third-quarter 2006 sales of £215 million, up 26%.

GSK noted that it filed an infringement case in 2003 against Ranbaxy, alleging its product would infringe a 'composition of matter' patent which expires in June 2009 and a trial date has not yet been set. If the UK drugs giant does apply for such an injunction within 45 days, Ranbaxy cannot launch its product until the court either rules on the injunction or decides the pending court case.