A selective endothelin-receptor antagonist to reduce blood pressure in patients with treatment-resistant hypertension: a randomised, double-blind, placebo-controlled trial.

Background: Hypertension cannot always be adequately controlled with available drugs. We investigated the blood-pressure-lowering effects of the new vasodilatory, selective endothelin type A antagonist, darusentan, in patients with treatment-resistant hypertension.

Methods: This randomised, double-blind study was undertaken in 117 sites in North and South America, Europe, New Zealand, and Australia. 379 patients with systolic blood pressure of 140 mm Hg or more (>/=130 mm Hg if patient had diabetes or chronic kidney disease) who were receiving at least three blood-pressure-lowering drugs, including a diuretic, at full or maximum tolerated doses were randomly assigned to 14 weeks' treatment with placebo (n=132) or darusentan 50 mg (n=81), 100 mg (n=81), or 300 mg (n=85) taken once daily. Randomisation was made centrally via an automated telephone system, and patients and all investigators were masked to treatment assignments. The primary endpoints were changes in sitting systolic and diastolic blood pressures. Analysis was by intention to treat. The study is registered with ClinicalTrials.gov, number NCT00330369.

Findings: All randomly assigned participants were analysed. The mean reductions in clinic systolic and diastolic blood pressures were 9/5 mm Hg (SD 14/8) with placebo, 17/10 mm Hg (15/9) with darusentan 50 mg, 18/10 mm Hg (16/9) with darusentan 100 mg, and 18/11 mm Hg (18/10) with darusentan 300 mg (p<0.0001 for all effects). The main adverse effects were related to fluid accumulation. Oedema or fluid retention occurred in 67 (27%) patients given darusentan compared with 19 (14%) given placebo. One patient in the placebo group died (sudden cardiac death), and five patients in the three darusentan dose groups combined had cardiac-related serious adverse events.

Interpretation: Darusentan provides additional reduction in blood pressure in patients who have not attained their treatment goals with three or more antihypertensive drugs. As with other vasodilatory drugs, fluid management with effective diuretic therapy might be needed.

Funding: Gilead Sciences.