Background: The number of hypertensive patients achieving treatment targets is not ideal with therapies that engage a single mechanism of action, and combination therapies using different mechanisms of action can increase drug efficacy in a synergistic way. Objective: This noninferiority study compared the clinical efficacy and safety profile of fixed-dose combination of amlodipine/losartan 5/50 mg and amlodipine 10 mg monotherapy in essential hypertensive patients who respond poorly to amlodipine 5 mg monotherapy. Methods: This was a double-blind, multicenter, randomized trial of hypertensive patients (N = 185) aged ≥18 years taking amlodipine 5 mg during the run-in treatment period but failed to achieve sitting diastolic blood pressure (DBP) <90 mm Hg. After randomization into the amlodipine/losartan 5/50 mg fixed-dose combination group (n = 92) and the amlodipine 10 mg monotherapy group (n = 93), treatment was maintained without dose escalation for 8 weeks. The noninferiority margin was prespecified as 4 mm Hg after 8 weeks of treatment for the difference of the average change in DBP between treatments. The primary efficacy evaluation of noninferiority was tested using a confidence interval approach with a 97.5% 1-sided lower confidence limit using the average difference in DBP measured at baseline and 8 weeks. Results: After 8 weeks, the DBP of both groups decreased from baseline by 8.9 (6.1) and 9.4 (7.5) mm Hg, respectively (difference = -0.5 [6.9] mm Hg, 95% CI: -2.5 to 1.5). Secondary end points of reductions in DBP after 4 weeks (-8.1 [6.7] vs -9.9 [7.3] mm Hg, difference = -1.8 mm Hg, 95% CI: -3.9 to 0.2) and sitting systolic blood pressure after 4 (-10.2 [11.8] vs -12.8 [10.2] mm Hg, difference = -2.6 mm Hg, 95% CI: -5.9 to 0.6) and 8 weeks (-12.2 [11.0] vs -13.4 [11.3] mm Hg, difference = -1.2 mmHg, 95% CI: -4.4 to 2.1) were comparable between the 2 treatment groups. There were 38 adverse events in 20 patients (21.7%) in the amlodipine/losartan 5/50 mg fixed-dose combination group and 31 in 24 patients (26.1%) in the amlodipine 10 mg monotherapy group; most were mild. There were 7 adverse events in 6 patients (6.5%) related to treatment in the fixed-dose combination group and 13 in 10 patients (10.9%) in the monotherapy group (P = 0.30). Conclusions: Fixed-dose combination amlodipine/losartan 5/50 mg was not inferior in terms of reductions in DBP after 8 weeks of treatment and had comparable safety profile to amlodipine 10 mg in patients who did not respond to amlodipine 5 mg monotherapy. ClinicalTrials.gov identifier: NCT00940667.
Bibliographical noteFunding Information:
This work was supported by Hanmi Pharmaceutical Ltd. in Korea. The authors wish to thank Dr. Mary E. Hanson of Merck Sharp & Dohme for editorial assistance, although she did not fulfill criteria for authorship. The authors have indicated that they have no conflicts of interest with regard to the content of this article.
All Science Journal Classification (ASJC) codes
- Pharmacology (medical)