Baxdrostat significantly reduces 24-hour ambulatory systolic blood pressure in individuals with resistant hypertension by −14.0 mm Hg more than a placebo, according to a recent phase 3 trial.

Published in The Lancet, the international, multicentre, randomised, double-blind, placebo-controlled Bax24 trial sought to determine whether the selective aldosterone synthase inhibitor baxdrostat could improve control of ambulatory blood pressure in patients with resistant hypertension.

The study screened 854 patients aged 18 years and older at 79 clinical sites across 22 countries who all had seated systolic blood pressure (SBP) ≥140 mm Hg and <170 mm Hg, despite receiving three or more antihypertensive medications, including a diuretic.

Following a two-week placebo run-in period, 217 patients (65% male, 70% White, median age 60.0 years (IQR 51.0–68.0)) with 24-hour ambulatory SBP ≥130 mm Hg were randomly assigned (1:1) to receive 2 mg baxdrostat or placebo orally once daily for 12 weeks, in addition to background therapy (stratified by baseline ambulatory SBP <140 mm Hg or ≥140 mm Hg).

Baxdrostat and blood pressure reduction

After 12 weeks, people taking baxdrostat had a very substantial reduction in blood pressure across the entire 24-hour period, including through the night and in the early morning, when the risk of heart attack and stroke is highest, the researchers said.

Indeed, the change from baseline in the least-squares mean 24 h ambulatory SBP was –16.6 mm Hg (95% CI −18.8 to −14.3) in the baxdrostat group (n=89) and −2.6 mm Hg (−4.7 to −0.4) in the placebo group (n=95); the estimated placebo-corrected difference was −14.0 mm Hg (−17.2 to −10.8; p<0.0001).

Adverse events occurred in 56 (52%) of 108 patients in the baxdrostat group and 40 (37%) of 109 patients in the placebo group. A confirmed potassium level of more than 6 mmol/L occurred in three (3%) of the 108 baxdrostat recipients and in none of the placebo recipients.

These results were presented the findings at a late breaking science session at the American Heart Association Scientific Sessions in November 2025.

Speaking at the time, Professor Bryan Williams, chair of medicine at the University College London and consultant physician at University College London Hospitals, said: ‘The Bax24 trial results are quite remarkable both in terms of the magnitude of blood pressure reduction and the fact that it was sustained across the entire 24-hour period.

‘The effectiveness of [baxdrostat] is unprecedented and suggests that the hormone aldosterone, which the drug targets, is playing a very important role in driving up blood pressure in many of the patients we struggle to control with existing treatments.

‘This is a real advance in our understanding of treatment resistant hypertension and a major breakthrough in new treatment options. So many people could potentially benefit from this new treatment.’

Supporting the BaxHTN study

These findings help to substantiate the results of the BaxHTN trial which was published by the same team in 2025 in the New England Journal of Medicine.

BaxHTN showed that baxdrostat could reduce blood pressure in people with uncontrolled or resistant hypertension, while Bax24 has now demonstrated that this effect can be sustained over 24 hours.

Sharon Barr, executive vice president, biopharmaceuticals research and development at AstraZeneca, which acquired baxdrostat in 2023, said: ‘The Bax24 data demonstrate the significant impact that baxdrostat’s long half-life and highly selective inhibition of aldosterone synthase can have in improving 24-hour and overnight blood pressure for patients with resistant hypertension.

‘Patients with elevated night-time blood pressure are especially vulnerable to cardiovascular events, including heart attack and stroke.

‘Together with the results from BaxHTN, these findings demonstrate the potential of baxdrostat to redefine what is possible for the millions of patients whose hypertension remains uncontrolled despite current therapies.’

This article was originally published by our sister publication Hospital Pharmacy Europe.