GlaxoSmithKline has said the US Food and Drug Administration will give its anti-clotting drug Arixtra a priority review for the treatment of patients with acute coronary syndromes.

Arixtra (fondaparinux sodium), 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.

The new indications under review include unstable angina and non-ST segment elevation myocardial infarction. About 3 million people are affected by ACS worldwide each year.

Approval of the new indicastion could lend some momentum to sales of Arixtra, which came in at £24 million in the first half of 2006 – the same tally it racked up for the whole of 2005 - after a relatively slow take-up since the drug's first launch in 2001 in the USA and subequent European introduction the following year.

This could help Arixtra gain some ground on its rival, Sanofi-Aventis' Lovenox (enoxaparin), which is currently market leader with sales of 1.2 billion euros ($1.5bn) in the first half of this year.