Comparative efficacy and safety of aliskiren, an oral direct renin inhibitor, and ramipril in hypertension: a 6-month, randomized, double-blind trial

Objectives This double-blind study compared long-term efficacy, safety and tolerability of the oral direct renin inhibitor aliskiren and the angiotensin-converting enzyme inhibitor ramipril alone and combined with hydrochlorothiazide in patients with hypertension. Methods After a 2-4-week placebo run-in, 842 patients [mean sitting diastolic blood pressure (msDBP) 95-109 mmHg] were randomized to aliskiren 150 mg (n = 420) or ramipril 5 mg (n = 422). Dose titration (to aliskiren 300 mg/ramipril 10 mg) and subsequent hydrochlorothiazide addition (12.5 mg, titrated to 25 mg if required) were permitted at weeks 6, 12, 18 and 21 for inadequate blood pressure control. Patients completing the 26-week active-controlled treatment period were re-randomized to their existing regimen or placebo for a 4-week double-blind withdrawal phase. Results Six hundred and eighty-seven patients (81.6%) completed the active treatment period. At week 26, aliskiren-based therapy produced greater mean reductions in mean sitting systolic blood pressure (17.9 versus 15.2 mmHg, P= 0.0036) and msDBP (13.2 versus 12.0mmHg, P=0.025), and higher rates of systolic blood pressure control (<140mmHg; 72.5 versus 64.1%, P=0.0075) compared with ramipril-based therapy. During withdrawal, blood pressure increased more rapidly after stopping ramipril than aliskiren-based therapy; median blood pressure reached 140/90 mmHg after 1 and 4 weeks, respectively. Blood pressure reductions were maintained with continued active treatment. Aliskiren therapy was well tolerated. Overall adverse event rates were similar with aliskiren (61.3%) and ramipril (60.4%); cough was more frequent with ramipril (9.5%) than aliskiren (4.1%). Conclusions Aliskiren-based therapy was well tolerated and produced sustained blood pressure reductions in patients with hypertension over 6 months, greater than those with ramipril-based therapy.