Clinical studies of CS-866, the newest angiotensin II receptor antagonist

Angiotensin II receptor blockers have shown widespread efficacy as antihypertensive medications. These agents bind selectively to angiotensin II type 1 (AT1) receptors, specifically blocking the renin–angiotensin system at the last step in its cascade. CS-866 is the most recently introduced drug in this class. This article presents integrated safety and efficacy data from 7 randomized, double-blind, placebo-controlled, parallel group studies in which once-daily CS-866 monotherapy was used in the treatment of patients with essential hypertension (sitting diastolic blood pressure ≥100 mm Hg and ≤115 mm Hg). Data from a total of 2,145 CS-866–treated patients were included in the efficacy analysis. Safety data were available from 2,540 CS-866–treated patients, with a cumulative exposure of 5,888 patient-months. The antihypertensive efficacy of the drug was assessed using both cuff blood pressure measurements and 24-hour ambulatory blood pressure monitoring. The data show that CS-866 is effective and safe for the treatment of hypertension. Dose-dependent reductions in both diastolic and systolic blood pressures occurred within 1 week of initiating treatment, and the response was almost maximal within 2 weeks. There was no difference in efficacy between younger (<65 years) and older (≥65 years) groups of patients. Trough-to-peak ratios showed that CS-866 retains the majority of its peak effect 24 hours after treatment, and is therefore suitable for once-daily dosing. Dizziness was the only treatment-emergent adverse event with which CS-866 was associated.