Evaluation of Candesartan Cilexetil in Black Patients with Systemic Hypertension: the ABC Trial

To assess the efficacy and tolerability of the angiotensin-II receptor blocker candesartan cilexetil, the Association of Black Cardiologists (ABC) coordinated a 12-week, multicenter, double-blind, placebo-controlled clinical trial in 304 black adults with a sitting diastolic blood pressure (DBP) of 91 to 105 mmHg, inclusive. The goal of the ABC Trial was to address previous reports suggesting that drugs that block the renin-angiotensin-aldosterone system may not be effective in controlling BP in hypertensive black individuals. Patients were randomized to receive candesartan cilexetil 16 mg (n = 156) or placebo (n = 148), once daily after a 4- to 5-week single-blind, placebo run-in period. Candesartan cilexetil and placebo doses were doubled if the trough (24 +/- 3 hours after dose) sitting DBP was 90 mmHg or higher after 4 weeks. If the DBP was 90 mmHg or higher at week 8, hydrochlorothiazide 12.5 mg was added to both placebo or candesartan cilexetil 32 mg. Candesartan cilexetil was significantly more effective than placebo in reducing trough sitting systolic BP (SBP) and DBP at week 8 (6.4/5.1 mmHg versus 1.3/2.7 mmHg) and at week 12 (9.3/7.5 mmHg versus 5.7/5.2 mmHg). Hydrochlorothiazide was added in 27 and 50% of patients in the candesartan cilexetil and placebo groups, respectively. Control and responder rates were consistently higher in the candesartan cilexetil treatment group at weeks 8 and 12. Discontinuation and adverse event rates were similar in the two groups. Candesartan cilexetil once daily was effective in reducing BP in a substantial proportion of an exclusively black hypertensive population. The combination of candesartan cilexetil plus hydrochlorothiazide demonstrated additional efficacy while maintaining an excellent tolerability profile.