Phase IV, 8-Week, Multicenter, Randomized, Active Treatment–Controlled, Parallel Group, Efficacy, and Tolerability Study of High-Dose Candesartan Cilexetil Combined With Hydrochlorothiazide in Korean Adults With Stage II Hypertension

Angiotensin receptor blockers: Focus on cardiac and renal injury

Angiotensin II, an important component of renin angiotensin system, is a potent vasopressor and its actions are mostly mediated via angiotensin II type 1 receptor (AT1R) and role of AT2R in counterbalancing the actions of AT1R stimulation are under extensive research. In addition to its physiological actions, angiotensin II plays important roles in the pathogenesis of atherosclerosis, hypertension, left ventricular hypertrophy, and heart failure. The effects of angiotensin II can be blocked by either suppressing its production by blocking angiotensin converting enzyme or by antagonizing its actions on AT1R using angiotensin II receptor blockers (ARBs). Instead of the extensive use of ARBs in the treatment of various cardiovascular diseases, proper selection of a particular ARB is crucial as the clinical condition of individual patient is different and also their economic status would play an essential role in medication compliance. Thus a critical review of the proven and promising actions of ARBs against various pathological conditions will be of great importance for the clinicians as well as for the researchers.

A Randomized, Multicenter, Double-blind, Placebo-controlled, 3 × 3 Factorial Design, Phase II Study to Evaluate the Efficacy and Safety of the Combination of Fimasartan/Amlodipine in Patients With Essential Hypertension

PURPOSE

The objective of this study was to evaluate the efficacy and safety of a fimasartan/amlodipine combination in patients with hypertension and to determine the optimal composition for a future single-pill combination formulation.

METHODS

This Phase II study was conducted by using a randomized, multicenter, double-blind, placebo-controlled, 3 × 3 factorial design. After a 2-week placebo run-in period, eligible hypertensive patients (with a sitting diastolic blood pressure [SiDBP] between 90 and 114 mm Hg) were randomized to treatment. They received single or combined administration of fimasartan at 3 doses (0, 30, and 60 mg) and amlodipine at 3 doses (0, 5, and 10 mg) for 8 weeks. The primary efficacy end point was the change in SiDBP from baseline and at week 8; secondary end points included the change in SiDBP from baseline and at week 4 and the changes in sitting systolic blood pressure from baseline and at weeks 4 and 8. Treatment-emergent adverse events (AEs) were also assessed.

FINDINGS

420 Korean patients with mild to moderate hypertension were randomly allocated to the 9 groups. Mean (SD) SiDBP changes in each group after 8 weeks were as follows: placebo, -6.0 (8.5) mm Hg; amlodipine 5 mg, -10.6 (9.2) mm Hg; amlodipine 10 mg, -15.9 (7.2) mm Hg; fimasartan 30 mg, -10.1 (9.1) mm Hg; fimasartan 60 mg, -13.0 (10.0) mm Hg; fimasartan 30 mg/amlodipine 5 mg, -16.2 (8.5) mm Hg; fimasartan 30 mg/amlodipine 10 mg, -19.5 (7.5) mm Hg; fimasartan 60 mg/amlodipine 5 mg, -16.6 (6.9) mm Hg; and fimasartan 60 mg/amlodipine 10 mg, -21.5 (8.3) mm Hg. All treatment groups produced significantly greater reductions in blood pressure compared with the placebo group. In addition, all combination treatment groups had superior reductions in blood pressure compared with the monotherapy groups. In the combination treatment groups, doubling fimasartan dose in the given dose of amlodipine did not show further BP reduction, whereas doubling amlodipine dose showed significantly further BP reduction in the given dose of fimasartan. During the study period, 75 (17.9%) of 419 patients experienced 110 AEs. Ninety-five AEs were mild, 9 were moderate, and 6 were severe in intensity. Eight patients discontinued the study due to AEs. There was no significant difference in incidence of AEs among groups (P = 0.0884). The most common AE was headache (12 patients [2.9%]), followed by dizziness (11 patients [2.6%]) and elevated blood creatine phosphokinase levels (6 patients [1.4%]).

IMPLICATIONS

Fimasartan combined with amlodipine produced superior blood pressure reductions and low levels of AEs compared with either monotherapy. Therefore, a single-pill combination with fimasartan 60 mg/amlodipine 10 mg will be developed. ClinicalTrials.gov: NCT01518998.

Improved simultaneous quantitation of candesartan and hydrochlorthiazide in human plasma by UPLC-MS/MS and its application in bioequivalence studies

A validated ultra-performance liquid chromatography mass spectrometric method (UPLC–MS/MS) was used for the simultaneous quantitation of candesartan (CN) and hydrochlorothiazide (HCT) in human plasma. The analysis was performed on UPLC–MS/MS system using turbo ion spray interface. Negative ions were measured in multiple reaction monitoring (MRM) mode. The analytes were extracted using a liquid–liquid extraction (LLE) method by using 0.1 mL of plasma volume. The lower limit of quantitation for CN and HCT was 1.00 ng/mL whereas the upper limit of quantitation was 499.15 ng/mL and 601.61 ng/mL for CN and HCT respectively. CN d₄ and HCT-¹³Cd₂ were used as the internal standards for CN and HCT respectively. The chromatography was achieved within 2.0 min run time using a C18 Phenomenex, Gemini NX (100 mm×4.6 mm, 5 µm) column with organic mixture:buffer solution (80:20, v/v) at a flow rate of 0.800 mL/min. The method has been successfully applied to establish the bioequivalence of candesartan cilexetil (CNC) and HCT immediate release tablets with reference product in human subjects.