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The Pharmaceutical Journal
Enoxaparin and tirofiban fail to show benefit for MI
A trial designed to determine whether enoxaparin (Clexane) and tirofiban (Aggrastat) could reduce the risk of adverse outcomes in heart attack patients who were either ineligible or too late for thrombolytic therapy has shown that neither therapy adds any benefit compared with unfractionated heparin.
Presenting the results at the American Heart Association scientific sessions in Chicago, Dr Marc Cohen, Newark Beth Israel Hospital, New Jersey, said: "There are clearly too many patients who are too late [for standard treatment]. The question is what do you do? There are no guidelines because there's been a relative paucity of information on this sizable group of patients." He added that at least one in five patients who experience a myocardial infarction (MI) and arrive at hospital in time to receive reperfusion therapy are not treated with a thrombolytic agent.
The study involved 1,224 patients with ST-segment elevation MI (STEMI) who had not received reperfusion therapy (thrombolytics or coronary intervention). Patients were randomised to one of four treatment options: enoxaparin plus placebo; enoxaparin plus tirofiban; unfractionated heparin plus placebo; or unfractionated heparin plus tirofiban.
The incidence of death, a second MI or recurrent angina at 30 days was similar for all treatment strategies (15.7 per cent for all patients treated with enoxaparin versus 17.3 per cent for all unfractionated heparin patients, P=0.471, and 16.6 per cent for all tirofiban patients versus 16.4 per cent for all placebo patients, P=0.896). There were no significant differences in the rates of major haemorrhage among the treatment regimens. "The primary endpoint of the study [to show that enoxaparin reduces adverse outcomes at 30 days] was not met in this challenging population. But it is fair to say that enoxaparin had a similar efficacy and safety profile to unfractionated heparin," Dr Cohen said.
He went on to say that adding tirofiban to the treatment regimen also failed to reduce adverse outcomes, although a post hoc analysis of patients treated within 12 hours appeared to show some benefit for tirofiban.
Commenting on the trial, Dr Sidney Smith, Chapel Hill, North Carolina, said that presentation of negative data was critical for improving patient care. "We need to turn to other therapies for this group of patients. And we need to educate patients to seek care sooner after the onset of symptoms," he concluded.
Citation: The Pharmaceutical Journal URI: 20008234