Study: New Blood Pressure Drug Ineffective

A study published in this month’s American Journal of Hypertension called into question the effectiveness of a new blood-pressure drug known as aliskiren. Dr. Jean E. Sealey of New York Presbyterian Hospital and Dr. John H. Laragha at the Weill Medical College of Cornell University in New York reviewed six different clinical trials regarding aliskiren and determined that the new drug is no more effective than previously existing treatments for hypertension.

According to the authors, “A review of six clinical trials of aliskiren involving [more than] 5,000 patients with mild to moderate hypertension indicated that this first of a new class of orally active antihypertensive drugs is no more effective than angiotensin-converting enzyme inhibitors (CEIs), angiotensin receptor blockers (ARBs), or diuretics for lowering blood pressure.”

Aliskiren is intended to reduce the body’s production of an enzyme known as renin, which has been shown to increase blood pressure. However, the authors note, “Although aliskiren suppresses plasma renin activity, it causes much greater reactive rises in plasma renin concentration than does any other antihypertensive class tested.” Therefore, the “consequences of its greater reactive increases in plasma renin concentration appear to offset its net ability to lower blood pressure, especially with higher doses.” In other words, the possibility exists that aliskiren actually leads to increases in blood pressure in patients with “highly reactive renin levels.”

“Until the possibility is eliminated of inducing increases in blood pressure with aliskiren in patients with highly reactive renin levels,” the authors conclude, “it seems safe and simple to stick to the less expensive, equally effective, and widely available generic CEI drugs for treating the renin factor in hypertension.”

Aliskiren was first approved by the FDA in March and had been expected to generate annual sales topping $1 billion. Aliskiren, sold by Novartis as Tekturna and Rasilez, is the first of a new class of orally active drugs that is intended to inhibit renin in the treatment of hypertension. This new class, however, is one of seven classes of drugs used to treat high blood pressure and the fourth of the seven that works by inhibiting renin production, although it is the first of those classes to be administered orally.

However, many of the other previously existing renin blockers, such as those cited in the new study, have lost their patent protections. Therefore, the development of aliskiren had been viewed as a major boon to Novartis since it still benefits from patent protection. Yet, as the study shows, the new drug is far costlier and not any more effective than the renin blockers that were previously available.