Fondaparinux: a pharmacoeconomic review of its use in the management of non-ST-segment elevation acute coronary syndrome.

Fondaparinux (Arixtra) is an anticoagulant that selectively inhibits activated factor X, thereby interrupting the blood coagulation cascade. In OASIS-5, a large pivotal trial in patients with non-ST-segment elevation acute coronary syndrome (NSTE-ACS), subcutaneous fondaparinux 2.5 mg once daily was noninferior to subcutaneous enoxaparin 1 mg/kg twice daily (both agents were administered over a mean of about 5 days in combination with antiplatelet therapy) in reducing death or ischaemic events at 9 days, and the efficacy was maintained for up to 6 months (study end). However, fondaparinux was associated with a significantly lower rate of bleeding than enoxaparin in the first 9 days, and at 3 and 6 months. This lower rate of bleeding led to lower long-term mortality and morbidity with fondaparinux than with enoxaparin. In modelled cost-utility analyses conducted from a healthcare payer perspective in Spain, France and the US with a lifetime horizon, fondaparinux once daily was predicted to be cost effective relative to enoxaparin twice daily with regard to the incremental cost per QALY gained. In Spain and the US, fondaparinux dominated enoxaparin (i.e. was less costly and more effective) and, in the French analysis, the incremental cost per QALY gained with fondaparinux versus enoxaparin was well within recommended thresholds. Results of short-term (6-month) cost analyses in the US and France also favoured fondaparinux over enoxaparin. Sensitivity analyses demonstrated that base-case conclusions were robust over a range of parameter estimates and assumptions, including plausible variations in baseline risk of a cardiac event or baseline risk of bleeding. In conclusion, in patients with NSTE-ACS receiving antiplatelet therapy, fondaparinux was cost effective relative to enoxaparin in cost-utility analyses in Europe and the US. This cost advantage primarily reflects the lower rate of bleeding with fondaparinux than with enoxaparin and the lower rate of mortality and morbidity over the long term.