Dual renin system blocking drug combo provides additional blood pressure-lowering effects

Apr 2 2007

A combination of two medicines that act against the effects of the enzyme renin are more effective in lowering blood pressure than either of the medicines alone, according to a study presented today at the American College of Cardiology's 56th Annual Scientific Session.

Aliskiren and valsartan have both been shown to have anti-hypertensive effects when given individually, but this is the first study that pairs the two in patients with mild to moderate high blood pressure. ACC.07 is the premier cardiovascular medical meeting, bringing together cardiologists and cardiovascular specialists to further breakthroughs in cardiovascular medicine.

Renin is an enzyme produced in the kidneys that initiates a cascade of events that generates angiotensin, a hormone which constricts the arteries, raising blood pressure as a result. Aliskiren is the first in a class of orally administered direct renin inhibitors, while valsartan is an angiotensin receptor blocker that impedes the effects of angiotensin by relaxing the blood vessels.

In a double-blind, placebo-controlled study, 1,797 patients were randomized to one of four treatment arms: the combination of 150 mg of aliskiren and 160 mg of valsartan, 150 mg of just aliskiren, 160 mg of just valsartan, or simply placebo once daily for four weeks. Then, the doses were doubled for a second four weeks. Blood pressure was checked at baseline and again and four and at eight weeks.

2 :2 : 2 Renin Blocker Therapy

Additionally, 24-hour ambulatory blood pressure monitoring, which records blood pressure readings around the clock, was performed in a subset of patients at the start of the study and at the conclusion of the eight weeks. All patients had mild to moderate hypertension [resting diastolic blood pressure of 95 to less than 110 mmHg]. Normal blood pressure is 120/80 mmHg or lower.

Endpoints for the study included change in systolic and diastolic blood pressure, and the rate of blood pressure control. Patients taking the combination of aliskiren and valsartan experienced the best blood pressure control rate of 49.3 percent. These patients reached the goal of 140/90 mmHg. For aliskiren alone, the control rate was 37.4 percent, valsartan alone 33.8 percent, and placebo 16.5 percent. There were no serious side effects in any of the dosage groups or the placebo group, indicating that the combination therapy was safe and tolerable for all participants

"Aliskiren and valsartan are both effective antihypertensives, but they function very differently," said Suzanne Oparil, M.D., of the University of Alabama at Birmingham School of Medicine and lead author of the study. "Marrying these two treatment options will give physicians a more effective way to control high blood pressure in their patients."

Dr. Oparil will present the results of "The Direct Renin Inhibitor Aliskiren in Combination With the Angiotensin Receptor Blocker Valsartan Provides Additional Blood Pressure-Lowering Effects Compared With Either Agent Alone in Patients With Hypertension" study on Monday, March 26 at 9:39 a.m. in Hall A.

http://www.acc.org