Antihypertensive efficacy and tolerability of aliskiren/hydrochlorothiazide (HCT) single-pill combinations in patients who are non-responsive to HCT 25 mg alone

OBJECTIVE: Thiazide diuretics such as hydrochlorothiazide (HCT) are a widely used first-line treatment for hypertension, but most patients will not achieve blood pressure (BP) control with HCT alone and so will require combination therapy. In this study the efficacy, safety and tolerability of a single-pill combination (SPC) of the direct renin inhibitor aliskiren with HCT were investigated in patients non-responsive to HCT 25 mg therapy. METHODS: In this study, 722 patients with hypertension and an inadequate response to 4 weeks of HCT 25 mg (mean sitting diastolic BP > or =90 and <110 mmHg) were randomized to once-daily, double-blind treatment for 8 weeks with an SPC of aliskiren/HCT 300/25 mg or 150/25 mg, or continued HCT 25 mg monotherapy. Least-squares mean changes in mean sitting systolic/diastolic BP (msSBP/DBP) from double-blind baseline were analyzed for the ITT population at week 8 endpoint. RESULTS: Aliskiren/HCT 300/25 mg and 150/25 mg SPCs lowered msSBP/DBP from baseline by 16.7/10.7 and 12.9/8.5 mmHg, respectively, both significantly greater reductions than HCT 25 mg alone (7.1/4.8 mmHg; both p < 0.001). Rates of BP control (<140/90 mmHg) were also significantly higher with aliskiren/HCT 300/25 mg (58%) and 150/25 mg (49%) than with HCT (26%; both p < 0.001). Aliskiren/HCT 300/25 mg provided significantly greater msSBP/DBP reductions and rates of BP control than the 150/25 mg SPC dose (all p < 0.05). Aliskiren/HCT SPC treatment showed similar tolerability to HCT alone and a numerically lower incidence of hypokalemia (serum potassium <3.5 mmol/L; aliskiren/HCT, 1.3-2.2%: HCT alone, 3.4%). CONCLUSION: Aliskiren/HCT SPCs provide clinically significant BP reductions and improved BP control rates in patients who are non-responsive to HCT 25 mg monotherapy. Limitations of the study were the mainly Caucasian patient population and the non-responder design.