Aliskiren, an Orally Effective Renin Inhibitor, Provides Antihypertensive Efficacy Alone and in Combination With Valsartan

Background: 

By blocking the renin-angiotensin-aldosterone system (RAAS) at its rate-limiting step, renin inhibition may provide improved RAAS suppression. We investigated the blood pressure (BP)-lowering effects of the oral direct renin inhibitor aliskiren, alone or in combination with the angiotensin receptor blocker valsartan.

Methods: 

In this multicenter, randomized, placebo-controlled, 8-week trial, 1123 patients with mild-to-moderate hypertension underwent a 3 to 4 week single-blind placebo run-in and were then randomized in a modified factorial study design to receive once-daily, double-blind oral treatment with placebo, aliskiren monotherapy (75, 150, or 300mg), valsartan monotherapy (80, 160, or 320mg), aliskiren and valsartan in combination, or valsartan/hydrochlorothiazide (160/12.5mg). The primary efficacy variable was the change from baseline in mean sitting diastolic BP (DBP) at endpoint.

Results: 

Once-daily oral treatment with aliskiren 300mg significantly (P<.0001) lowered mean sitting DBP and systolic BP (SBP) compared with placebo; aliskiren monotherapy demonstrated a safety and tolerability profile comparable to placebo. Changes in DBP and SBP were fitted to a first-order dose-response surface (lack-of-fit test, P=.65), which showed that aliskiren and valsartan alone and in combination produced dose-related reductions in DBP and SBP. Coadministration of aliskiren and valsartan produced a greater antihypertensive effect than either drug alone, comparable in magnitude to the effect of valsartan/hydrochlorothiazide, with similar tolerability to the component monotherapies and to placebo.

Conclusions: 

Aliskiren monotherapy provides antihypertensive efficacy and placebo-like tolerability in patients with hypertension. Aliskiren and valsartan in combination may provide additive BP-lowering effects with maintained tolerability.