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.