ximelagatran and Acute-Coronary-Syndrome

Despite widespread adoption of acetylsalicylic acid and P2Y12 receptor inhibitor therapy as the standard of care for secondary event prevention in patients with acute coronary syndrome (ACS), the rate of cardiovascular death or myocardial infarction following discharge is approximately 24-31% over five years, indicating an important unmet need to reduce further the risk of recurrent ACS events. Because thrombin has a role in arterial thrombus generation, a mechanistic rationale exists for adding an anticoagulant to dual antiplatelet therapy to reduce cardiovascular event rates and mortality. The direct thrombin inhibitor dabigatran and the direct Factor Xa inhibitors rivaroxaban and apixaban have been investigated for this application, with only rivaroxaban successfully completing a phase III trial. These results suggest that dose selection is of paramount importance in this indication, with lower anticoagulant doses (relative to those used in other indications, such as stroke prevention in atrial fibrillation) plus low-dose acetylsalicylic acid potentially improving cardiovascular outcomes. This article reviews clinical trial data of anticoagulants for secondary event prevention in patients with ACS; it also discusses the mechanistic reasons that may underlie these observations and looks towards the potential impact of findings from the ATLAS ACS 2 TIMI 51 trial on clinical practice.

Topics: Acute Coronary Syndrome; Administration, Oral; Anticoagulants; Azepines; Azetidines; Benzamides; Benzimidazoles; Benzylamines; beta-Alanine; Dabigatran; Humans; Morpholines; Pyrazoles; Pyridones; Rivaroxaban; Thiophenes; Thrombin; Vitamin K

Acute coronary syndrome (ACS) occurs as a result of atherosclerotic plaque rupture and subsequent platelet activation and coagulation leading to thrombus formation and coronary occlusion. Thrombin and activated factor X (FXa) are key elements in the coagulation cascade. The use of anticoagulants in ACS, both in the acute phase and in the long term, has improved prognosis by reducing thrombotic events, but is associated with an increased risk of bleeding. In recent years, new oral anticoagulants have been developed that do not require monitoring and produce a lower risk of bleeding. Rivaroxaban is the only drug with a favorable risk-benefit profile in patients with ACS. The ATLAS ACS TIMI 2-51 is the first phase III trial demonstrating that the addition of low-dose rivaroxaban to optimal antiplatelet therapy reduces mortality, cardiovascular mortality, infarct or stroke without significantly increasing fatal bleeding.

Topics: Acute Coronary Syndrome; Administration, Oral; Anticoagulants; Azepines; Azetidines; Benzamides; Benzimidazoles; Benzylamines; beta-Alanine; Clinical Trials, Phase III as Topic; Dabigatran; Drug Administration Schedule; Humans; Morpholines; Pyrazoles; Pyridones; Rivaroxaban; Thiophenes

Indirect systemic and direct oral factor Xa and direct oral factor IIa inhibitors with improved pharmacologic profiles compared with heparins and vitamin K antagonists are currently in clinical development. This overview focuses on the indirect antithrombin dependent pentasaccharide derivatives of idraparinux and on the most advanced oral direct inhibitors to factor Xa (rivaroxaban and apixaban) and IIa (dabigatran). Specifically, the results of dose-finding studies for the prevention of venous thromboembolism after elective orthopedic surgery, the results of dose-finding studies for treatment of acute venous thromboembolism including prolonged prophylaxis of recurrent events, and the designs of ongoing clinical trials are reviewed.

Topics: Acute Coronary Syndrome; Administration, Oral; Anticoagulants; Atrial Fibrillation; Azetidines; Benzimidazoles; Benzylamines; Clinical Trials as Topic; Dabigatran; Factor Xa Inhibitors; Glycine; Humans; Infusions, Parenteral; Morpholines; Oligosaccharides; Piperazines; Prothrombin; Pyrazoles; Pyridines; Pyridones; Rivaroxaban; Thiophenes; Thrombin; Thrombosis; Venous Thromboembolism