It certainly wasn't third time lucky for drug giants Bayer and Johnson & Johnson after US regulators yet again refused to approve wider uses of their bloodthinner Xarelto (rivaroxaban).

The US Food and Drug Administration has issued a third rejection for the drug to reduce the risk of heart attack, stroke or death in patients with acute coronary syndrome (ACS).

It also turned down for the second time a separate supplemental application to market Xarelto for reducing the risk of stent thrombosis in the same population, in combination with standard antiplatelet therapy.

But the move comes as no surprise, given that FDA advisors last month voted 10-0, with one abstention, against approval to reduce the risk of secondary cardiovascular events in patients with ACS, on grounds that available data failed to show sufficient proof that the factor Xa inhibitor offered significant benefit.

Xarelto is approved for six uses already in the US - reducing the risk of strokes in patients with nonvalvular AF, as a treatment for deep vein thrombosis and pulmonary embolism and for reducing the risk of blood clots in the legs and lungs of people who have had hip or knee replacement surgery. It was approved in Europe for ACS in May last year.

The company said it is “evaluating the contents of the [complete response letters] and will determine the appropriate next steps.”

ACS is a complication of coronary heart disease - the leading cause of death in the US - and occurs when a blood clot blocks a coronary artery, reducing blood supply to the heart and potentially leading to heart attack of unstable angina. Around 1.2 million patients are discharged from hospital in the country with a diagnosis of ACS every year, illustrating the scale of the problem.