'Arixtra has got a lot of ground to make up against other low molecular weight heparins. In addition to being the market leader, Lovenox is licensed for STEMI, so currently Arixtra would have to compete off-label for that niche.'

GSK hopes the findings can help it compete against Sanofi Aventis' Lovenox, which also got a boost Tuesday from a separate study that found it significantly reduces the risk of death or repeat heart attack in patients who had already suffered a heart attack.

Some experts think the Lovenox study, known as ExTRACT-TIMI 25, indicates the drug should become the anticoagulant of choice for treating heart attack patients.

"Based on the results of the ExTRACT-TIMI 25 trial, we believe that the [Lovenox] strategy is now the preferred anticoagulant regimen to use in heart attack patients who receive clot-busting drugs," said Eugene Braunwald, chairman of the TIMI Study Group at Brigham and Women's Hospital and a professor at Harvard Medical School.

A Lot of Ground to Make Up

GSK spokeswoman Michele L. Meeker told United Press International the company now plans to file the data from the Arixtra study, known as OASIS-6, and other research with regulatory authorities in an attempt to get an indication for the treatment of acute coronary syndrome patients.

"We will work as quickly as possible to get the files submitted over the next few months," Meeker said.

However, some analysts think Lovenox will likely retain its market share and top spot in the $2.4 billion antithrombotic field.

"The OASIS-6 findings are may lead to some off-label use, but I don't think it's going to revolutionize antithrombotic use in [ST-segment elevation myocardial infarctions]," Decision Resources analyst Mark Thornton told UPI.

"Arixtra has got a lot of ground to make up against other low molecular weight heparins," Thornton added. "In addition to being the market leader, Lovenox is licensed for STEMI, so currently Arixtra would have to compete off-label for that niche," he noted.

Arixtra sales account for only $40 million of the $2.4 billion antithrombotic market.

Another constraining factor is that Arixtra's patent expires in 2006 in the United States and 2008 in Europe. The generic erosion may be limited, however, because Arixtra is difficult to manufacture, Thornton said.

Reduces Mortality and Reinfarction Early

In the OASIS-6 study, which appears in the April 5 issue of the Journal of the American Medical Association and was presented Tuesday at the American College of Cardiology annual conference in Atlanta, death or reinfarction at 30 days was reduced from 11.2 in STEMI patients who received standard anti-thrombotic therapy to 9.7 percent in the group treated with Arixtra.

No benefit was seen in patients undergoing percutaneous coronary interventions, such as angioplasty.

"In summary, [Arixtra] reduces mortality and reinfarction early, and this benefit persists long term," Salim Yusuf of McMaster University and Hamilton Health Services in Ontario, Canada, and colleagues wrote in JAMA. "The OASIS-6 results confirm the value and safety of [Arixtra] as a simple and widely applicable antithrombotic therapy in a broad group of patients with acute coronary syndrome," the study authors added.

In the Lovenox ExTRACT-TIMI 25 trial, Lovenox was compared against unfractionated heparin in heart attack patients. The results, which were presented at the ACC meeting and will be published in the New England Journal of Medicine, showed that Lovenox reduced the risk of death or recurrent non-fatal heart attack by 17 percent.

"The results of this trial are dramatic and significant," said the study's lead author, Elliott Antman of Brigham and Women's Hospital. "A strategy using [Lovenox] prevents more patients from dying or having a second heart attack within 30 days of treatment compared to the strategy using unfractionated heparin, which up to now has been considered the standard blood thinner regimen used to support fibrinolytic therapy."