Efficacy and Safety of Combination Therapy With Low Dose of Telmisartan and S-Amlodipine in Patients With Hypertension: A Randomized, Double-Blind, Multicenter, Therapeutic Confirmatory, Phase III Clinical Trial

Abstract

Purpose: This randomized, double-blind, multicenter, phase III clinical trial aimed to evaluate the efficacy and safety of telmisartan 20 mg and s-amlodipine 1.25 mg, a fixed-dose combination (Tel/S-Amlo) versus telmisartan 20 mg single therapy or s-amlodipine 1.25 mg single therapy for initial treatment in patients with hypertension. Methods: After a wash-out/therapeutic lifestyle change period of ≥4 weeks, a total of 235 eligible patients were randomized and received 1 of 3 treatments for 8 weeks: (1) telmisartan 20 mg/s-amlodipine 1.25 mg (Tel/S-Amlo), (2) telmisartan 20 mg (Tel), or (3) S-amlodipine 1.25 mg (S-Amlo). The primary endpoint was the efficacy evaluation of Tel/S-Amlo by comparing changes in mean sitting systolic blood pressure (msSBP) from baseline after 8 weeks of treatment. Findings: At 8 weeks, the least square (LS) mean (SE) change in msSBP was −20.04 (1.46) mm Hg in the Tel/S-Amlo group, compared with –16.44 (1.46) mm Hg in the Tel group (between-group difference –3.60 (1.78) mm Hg, P-value = 0.0451). Similarly, the Tel/S-Amlo group showed a change of −21.12 (1.33) mm Hg versus −15.58 (1.32) mm Hg in the S-Amlo group (between-group difference –5.53 (1.61) mm Hg, P-value = 0.0008). There were no statistically significant differences in the incidence of overall AEs and adverse drug reactions among the 3 groups, and no serious adverse events occurred during the study. Implications: Combination therapy with a low-dose of telmisartan and s-amlodipine may be a promising initial treatment for patients with hypertension. Clinical trial registration: This study was registered in ClinicalTrials.gov (NCT06121518). © 2026 The Author(s)