Results show a significant 63 per cent relative risk reduction (2.3% vs 6.3%) in major venous thromboembolism (VTE) - proximal deep vein thrombosis (DVT) and pulmonary embolism (PE) - when treated with EXANTA, compared to standard prophylaxis with enoxaparin (40mg od). The relative risk reduction in major VTE was 67 per cent (1.8% vs 5.5%) for total hip replacement and 60 per cent (3.3% vs 8.2%) for total knee replacement surgery.
EXPRESS is a randomised, double-blind study of 2,800 patients that compares the efficacy and safety of EXANTA (subcutaneous melagatran followed by oral ximelagatran), with that of the routinely used prophylactic treatment, subcutaneous enoxaparin (40mg od), for the prevention of venous thromboembolism (VTE) following major hip and knee replacement surgery.
"These results indicate that in the future, ximelagatran could more efficiently reduce this risk than current treatments. In addition, a treatment that can be taken orally and does not require coagulation monitoring, would improve the treatment benefit and patient acceptance," commented Associate Professor Bengt Eriksson, principal investigator of the EXPRESS trial. "Prophylactic treatment is needed before major orthopaedic surgery in order to prevent development of VTE, which can lead to serious complications."
Between 45-57 per cent of patients undergoing total hip replacement without thromboprophylaxis develop DVT1 (deep vein thrombosis), a potentially fatal condition. Similarly, the rate of DVT for patients undergoing total knee replacement is 40-84 per cent1.
Both first and second stage primary endpoints of EXPRESS were met, including a 24 per cent (20.3% vs 26.6%) reduction in the risk of total VTE (proximal and distal DVT and PE) seen following prophylactic treatment (thromboprophylaxis) with EXANTA, compared to enoxaparin.
The EXANTA treatment regimen in EXPRESS shows a good balance between efficacy and safety. A small increase in surgery-related bleeding was observed compared to enoxaparin, although importantly, there were no differences between treatments in clinically important bleeding events (defined as fatal, critical organ or requiring re-operation).
EXANTA is the first Oral DTI to be submitted for regulatory approval and works by inhibiting thrombin, a key enzyme involved in the blood clotting (coagulation) process. AstraZeneca submitted a filing for a European licence for EXANTA (ximelagatran/melagatran) in prevention of VTE following major orthopaedic surgery in July 2002. This was the first regulatory submission for EXANTA. In the United States, the orthopaedic surgery trial programme, EXULT, remains on track.
"These important results confirm the efficacy and potential benefits of EXANTA," said Hamish Cameron, Vice President and Head of Cardiovascular Therapy Area, AstraZeneca. "EXANTA, once approved, could offer advantages over existing products in the anticoagulant market and strengthens the AstraZeneca cardiovascular portfolio. We see these results as a key step in introducing a fundamentally new approach to oral anti-coagulation."
EXANTA represents a potential medical breakthrough in the prevention and treatment of thromboembolism and meets a clearly defined unmet medical need for anticoagulation treatment, without coagulation monitoring and dosage titration.
Thrombosis is one of the largest causes of morbidity and mortality in the Western world. There are nearly four million events of thromboembolic disease (including stroke, deep vein thrombosis/pulmonary embolism and myocardial infarction) each year throughout the EU and Japan.