GlaxoSmithKline plc announced late-breaking clinical trial results of the OASIS 6 trial that compared its antithrombotic product Arixtra (fondaparinux sodium) to standard therapy in acute coronary syndrome (ACS) patients with ST elevation MI (STEMI).

The overall results of the study demonstrated superiority of fondaparinux to standard therapy (unfractionated heparin or placebo) in reducing risk of death or recurrent heart attack (risk reduction of 14% at day 30, p=0.008), with a significant reduction observed as early as day 9 (risk reduction of 17%, p=0.003). Furthermore, fondaparinux showed a significant reduction in all cause mortality (secondary endpoint) at day 9 (risk reduction 13%, p=0.043), which was maintained until the end of the study (risk reduction 12%, p=0.029), stated a company release.

In OASIS 6, the incidence of severe haemorrhage at Day 9 was similar between fondaparinux and standard therapy treated patients. In addition, OASIS 6 showed that fondaparinux was associated with a significant net benefit-risk as assessed by the composite of efficacy and safety endpoints of death, recurrent MI and severe haemorrhage at all time points (at day 30 risk reduction was 14%, p=0.005).

"Results of OASIS 6 showed the benefit of fondaparinux for both morbidity and mortality and may prove to be a valuable treatment option for these ACS patients in the future, " Dr. Salim Yusuf, principal investigator of the study, and Professor of Medicine, McMaster University and Hamilton Heath Sciences, Ontario, Canada said adding, "In addition, the bleeding incidences observed in OASIS 5 and 6, coupled with the efficacy outcomes, demonstrated that fondaparinux offered a positive net-benefit risk profile in patients across a range of ACS."

The OASIS 5 and 6 programmes studied over 32,000 patients worldwide. OASIS 6 results are broadly consistent with the large companion study OASIS 5 conducted in the acute treatment of patients with chest pain (unstable angina)/myocardial infarction (non-ST-segment elevation MI).

Fondaparinux is not currently approved in any country for patients with ACS.

The OASIS 6 programme is an international, randomised, double-blind study assessing the efficacy and safety of fondaparinux in patients with STEMI. OASIS 6 evaluated 12,092 patients in 447 sites across 41 countries.

The primary objective of the study was to evaluate whether fondaparinux is superior to standard therapy (UFH or placebo) in preventing death or recurrent myocardial infarction (MI) up to day 30 in patients with STEMI. The safety profile of fondaparinux compared with standard therapy was evaluated in terms of severe haemorrhage up to day 9.

Secondary objectives included the evaluation of whether fondaparinux has a beneficial effect compared to standard therapy in preventing death or recurrent MI at day 9 and whether this was sustained up to day 90 and 180, as well as to evaluate whether fondaparinux was superior to standard therapy in preventing death, recurrent MI and refractory ischaemia at all time points. Minor and major bleeding as well as adverse events were included in secondary safety endpoints.

The OASIS 6 (Organization to Assess Strategies for Ischaemic Syndrome) trial evaluated more than 12,000 patients and was presented at the American College of Cardiology's (ACC) 55th Scientific Session in Atlanta, GA.