BASELINE CHARACTERISTICS OF PATIENTS IN BAXHTN: A PHASE 3 TRIAL OF THE ALDOSTERONE SYNTHASE INHIBITOR BAXDROSTAT IN PATIENTS WITH UNCONTROLLED OR RESISTANT HYPERTENSION

Objective: Baxdrostat is a novel, highly potent, selective and competitive aldosterone synthase inhibitor that reduced systolic blood pressure (SBP) in patients with resistant hypertension (rHTN) in a Phase 2 trial. BaxHTN (NCT06034743) is the subsequent international, randomised, double-blind, Phase 3 trial conducted to assess the efficacy and safety of baxdrostat versus placebo in patients with uncontrolled HTN (uHTN) or rHTN. Here, we report the baseline characteristics of patients included in the BaxHTN trial. Design and method: We screened patients aged ≥ 18 years with either uHTN or rHTN, defined as seated SBP between ≥ 140 and < 170 mmHg despite two antihypertensive treatments (AHT) or ≥ 3 AHT, respectively, including a diuretic, at maximum tolerated dose for ≥ 4 weeks prior to screening. Other inclusion criteria included a serum potassium level between ≥ 3.5 and < 5.0 mmol/L and an estimated glomerular filtration rate of ≥ 45 mL/min/1.73 m2. Key exclusion criteria included the need for a mineralocorticoid receptor antagonist during the trial. After screening, patients entered a 2-week placebo run-in period. If, at the end of the 2-week run-in period, patients had a seated SBP of ≥ 135 mmHg on stable background AHT, 80-120% adherence to placebo and good adherence to background AHT, they were randomised 1:1:1 to baxdrostat 2 mg, baxdrostat 1 mg or placebo once daily for 12 weeks. The primary endpoint is the change from baseline in seated SBP at Week 12. Results: As of 7 February 2025, 782 patients were randomised (uHTN, n=221; rHTN, n=561); see Table for baseline characteristics. Mean (standard deviation) age and body-mass index were 61.2 (11.8) years and 31.2 (6.2) kg/m2, respectively. Around a third of patients had type 2 diabetes. Mean (standard deviation) SBP at randomisation in patients with uHTN and rHTN, respectively, was 148.4 (9.1) and 149.1 (9.4) mmHg. The three most common background AHT were diuretic, calcium channel blocker and angiotensin receptor blocker. The median (range) number of AHT in patients with rHTN was 3 (3-8). Conclusions: Patients randomised in BaxHTN had elevated SBP despite multiple AHT. BaxHTN will assess the BP-lowering effect and safety of baxdrostat in these patients.