Add-on effect of hydrochlorothiazide 12.5 mg in Japanese subjects with essential hypertension uncontrolled with losartan 50 mg and amlodipine 5 mg

This study assessed the antihypertensive efficacy of a triple combination, fixed-dose therapy of losartan 50 mg (L50)/hydrochlorothiazide 12.5 mg (H12.5)/amlodipine 5 mg (A5) versus co-administration of L50 plus A5 (L50+A5) in Japanese subjects with uncontrolled essential hypertension. Initially, all subjects received single-blind treatment with L50+A5 for 8 weeks. Subjects whose blood pressure (BP) remained stable within pre-specified limits during the last 4 weeks of L50+A5 administration were randomized (n =3 27) to double-blind treatment with L50/H12.5/A5 or L50+A5 for 8 weeks. Primary and secondary efficacy endpoints were mean change from baseline to Week 8 in trough diastolic BP (DBP) and trough systolic BP (SBP), respectively. Safety was assessed throughout the study. The treatment difference for L50/H12.5/A5 versus L50+A5 in mean change from baseline in DBP at Week 8 was -1.1 mm Hg (95% confidence interval (CI) -2.7, 0.6; P = 0.205). However, the treatment difference in mean change from baseline in SBP at Week 8 was -3.2 mm Hg (95% CI: -5.7, -0.8; P=0.011). A chance imbalance in the change in DBP before randomization between groups was identified in a post-hoc analysis as a major reason for the smaller-than-expected difference in DBP between groups. The overall safety profile was generally similar between groups. In conclusion, treatment with L50/H12.5/A5 for 8 weeks did not demonstrate a significant difference in DBP reduction, but demonstrated a nominally significant difference in SBP reduction, compared with L50+A5. L50/H12.5/A5 was well tolerated. (ClinicalTrials.gov identifier NCT01302691.).