Long-term safety and tolerability of the oral direct renin inhibitor aliskiren with optional add-on hydrochlorothiazide in patients with hypertension: a randomized, open-label, parallel-group, multicentre, dose-escalation study with an extension phase.

BACKGROUND: Most patients with hypertension will require combination therapy with at least two agents from different antihypertensive classes to achieve blood pressure (BP) control. Thiazide diuretics, such as hydrochlorothiazide (HCTZ), are widely used in combination therapy. The volume reduction with these agents stimulates the renin-angiotensin system (RAS), making RAS inhibitors such as the direct renin inhibitor aliskiren a logical choice for combination therapy with HCTZ.

OBJECTIVE: The aim of this study was to investigate the long-term safety, tolerability and efficacy of the direct renin inhibitor aliskiren, with or without addition of the diuretic HCTZ.

METHODS: In the 12-month core study, patients with hypertension (mean sitting diastolic BP ≥90 mmHg and <110 mmHg) were randomized in a 3 : 2 ratio to once-daily aliskiren 150 mg or 300 mg. At months 2, 3, 4, 6 and 9, treatment was adjusted in patients not achieving a BP goal of <140/90 mmHg. Patients not at goal on aliskiren 150 mg once daily were up-titrated to aliskiren 300 mg once daily. Patients not at goal with aliskiren 300 mg once daily received add-on HCTZ 12.5 mg once daily, which was up-titrated to 25 mg once daily if BP remained inadequately controlled. At month 12, patients who received aliskiren/HCTZ 300 mg/25 mg once daily for at least 8 months in the core study were eligible to enter a 4-month extension study.

RESULTS: Overall, 1625/1955 patients completed the core study, and 870/1955 patients received add-on HCTZ; 189/198 patients completed the 4-month extension. Aliskiren, with or without add-on HCTZ, was generally well tolerated; the incidence of adverse events (AEs) during the core study was similar among the four final treatment groups. The most frequently reported AEs in the core and extension studies were mild and transient cases of nasopharyngitis, headache and dizziness. Few patients exhibited laboratory abnormalities. Overall, aliskiren, with or without add-on HCTZ, reduced mean BP by 18.0/12.7 mmHg at core study endpoint, and 61.2% of patients achieved BP control. BP reductions with aliskiren/HCTZ 300 mg/25 mg combination therapy at the core study endpoint were maintained during the extension study.

CONCLUSION: In patients with hypertension, long-term treatment with aliskiren, with or without add-on HCTZ, is well tolerated and provides effective BP lowering that is sustained over 12 months.