The cost-effectiveness of bosentan in the United Kingdom for patients with pulmonary arterial hypertension of WHO functional class III.

OBJECTIVES To assess whether bosentan or no active intervention, in addition to palliative care, is the more cost-effective first-line treatment option for patients with idiopathic pulmonary arterial hypertension (iPAH) or PAH associated with connective tissue disease (PAH-CTD) of WHO functional classification (FC) III in the United Kingdom. METHODS A cost-utility model simulated the treatment of patients with PAH of FC III. Patients remained on the selected intervention until death or clinical deterioration to FC IV, which would trigger initiation of epoprostenol treatment. The initial first-line treatment choice was assumed to not affect survival, but to affect the time until clinical deterioration, with this assumption being relaxed in sensitivity analyses. The distribution of time to clinical deterioration was estimated from long-term clinical trial databases of bosentan and from published literature. Utility associated with FC was taken from published literature. Costs were sourced from published literature and from specialist PAH centers. The time horizon was that of patients' lifetimes, with costs and benefits discounted at 3.5% per annum. RESULTS In the base case, bosentan dominated no active intervention because of the longer time to clinical deterioration and therefore the reduced time, per patient, spent in FC IV, which was associated with high costs of epoprostenol and reduced utility. In sensitivity analyses, bosentan was estimated to be more cost-effective than no active intervention, provided that any survival benefit was not greater than 2 years for patients with iPAH and 1 year for those with PAH-CTD. CONCLUSIONS Bosentan is likely to be a more cost-effective first-line therapy for patients with PAH FC III in the UK than no active intervention.