The US Food and Drug Administration (FDA) has approved the inclusion in labeling of data from a clinical trial program showing that AstraZeneca's angiotensin II receptor blocker (ARB) Atacand (candesartan cilexetil) was superior to Merck's ARB Cozaar (losartan potassium) in lowering both systolic and diastolic blood pressure, when administered at the maximum recommended once-daily doses. The approval follows the unanimous recommendation of the FDA Cardiovascular and Renal Drugs Advisory Committee that concluded that Atacand demonstrated greater antihypertensive efficacy in reducing systolic blood pressure (SBP) by about 3 mm Hg and diastolic blood pressure (DBP) by about 2 mm Hg compared to losartan potassium in the CLAIM clinical trial program. Atacand is the first and only ARB to include data in its labeling, showing that it is significantly more effective at lowering blood pressure compared to another agent in the ARB class.

The FDA approval was based on data from the CLAIM program which included two, eight-week, multi-center, double-blind, forced-titration, randomized, head-to-head comparator studies in more than 1200 hypertensive patients. In the first CLAIM study, Atacand at the maximum once-daily dose of 32 mg reduced trough sitting SBP by 13.3 mm Hg and trough sitting DBP by 10.9 compared to the 9.8 mm Hg and 8.7 mm Hg for the once-daily maximum dose of 100 mg losartan potassium, a difference of 3.5/2.2 mm Hg. In the second CLAIM study, Atacand 32 mg reduced SBP by 13.4 mm Hg and DBP by 10.5 mm Hg compared to 10.1 mm Hg and 9.1 mm Hg for 100 mg losartan potassium, a difference of 3.4/1.5 mm Hg.

Patients were randomized to receive either Atacand 16 mg or losartan potassium 50 mg. After two weeks, doses were increased to 32 mg of Atacand or 100 mg of losartan potassium for the remaining six weeks of the study. The study population averaged 55 years of age; 42 percent were female, and 19 percent were black. The average baseline blood pressure was 152/100 mm Hg.

In both studies, Atacand consistently lowered trough and peak blood pressure to a greater degree than losartan potassium. Even at 48 hours post-dose at the end of the study, SBP and DBP were significantly lower for Atacand than for losartan potassium.