AstraZeneca Reports Positive Phase III Bax24 Results, Reinforcing Baxdrostat’s Potential as a Novel Treatment for Hard-to-Control Hypertension

AstraZeneca Reports Positive Phase III Bax24 Results, Reinforcing Baxdrostat’s Potential as a Novel Treatment for Hard-to-Control Hypertension

(IN BRIEF) AstraZeneca reported positive Phase III Bax24 trial results showing that baxdrostat achieved a significant and clinically meaningful reduction in 24-hour ambulatory systolic blood pressure in patients with treatment-resistant hypertension. The once-daily oral therapy was well tolerated and maintained efficacy across the entire day, including early morning hours when cardiovascular risk is highest. Baxdrostat’s selective inhibition of aldosterone synthase and its long half-life contribute to its strong blood pressure-lowering effects. The data support AstraZeneca’s plan to advance regulatory submissions and explore baxdrostat across additional conditions influenced by aldosterone, such as chronic kidney disease and heart failure prevention.

(PRESS RELEASE) CAMBRIDGE, 7-Oct-2025 — /EuropaWire/ — AstraZeneca announced positive top-line results from the Phase III Bax24 trial, demonstrating that baxdrostat, a highly selective aldosterone synthase inhibitor, achieved a statistically significant and clinically meaningful reduction in 24-hour ambulatory systolic blood pressure (SBP) compared with placebo at 12 weeks. The reduction was consistent throughout the 24-hour cycle, including the early morning period — a time when patients with hypertension face the greatest risk of cardiovascular events such as heart attack and stroke.

The Bax24 study enrolled patients with treatment-resistant hypertension (rHTN), who received either baxdrostat 2mg or placebo in addition to their standard therapy. The treatment was well tolerated, with a safety profile consistent with earlier trials, including the BaxHTN study. These findings reinforce baxdrostat’s potential to address a major unmet medical need among patients whose blood pressure remains uncontrolled despite multiple medications.

“The Bax24 results show that a once-daily baxdrostat regimen can deliver highly clinically meaningful reductions in 24-hour systolic blood pressure, including in the morning when patients are at greater risk of heart attack and stroke. These results are groundbreaking and together with the BaxHTN results mean we have the potential to change our treatment approach for the many patients whose hypertension remains uncontrolled despite current therapies,” said Dr. Bryan Williams, Chair of Medicine at University College London and primary investigator of the trial.

Sharon Barr, Executive Vice President of BioPharmaceuticals R&D at AstraZeneca, added:
“This second Phase III trial of baxdrostat shows substantial improvement in blood pressure, which reflects its durable half-life of up to 30 hours and highly selective inhibition of aldosterone synthase. Too many patients today have hypertension that remains hard-to-control throughout the day and night, making them especially vulnerable to cardiac events. We are advancing our regulatory filings and rapidly progressing our clinical program for baxdrostat as both mono- and combination-therapy across multiple conditions where aldosterone plays a key role, including primary aldosteronism, chronic kidney disease, and heart failure prevention.”

The Bax24 Phase III trial was a randomized, double-blind, placebo-controlled study evaluating 2mg baxdrostat administered once daily for 12 weeks. It included 218 patients randomized 1:1 to receive baxdrostat or placebo. The primary endpoint measured the change in ambulatory 24-hour average systolic blood pressure at Week 12, with additional endpoints assessing day- and night-time averages, seated SBP, and target SBP achievement rates.

Hypertension affects approximately 1.4 billion people globally, and nearly half of U.S. patients receiving treatment still fail to achieve adequate blood pressure control. Uncontrolled hypertension, particularly resistant hypertension, significantly increases the risk of cardiovascular and kidney disease. Research has shown that 24-hour ambulatory blood pressure readings are more accurate predictors of cardiovascular risk than clinic-based measurements, with each 9.5 mmHg rise in SBP associated with a 30% increase in all-cause mortality.

Baxdrostat, a first-in-class oral small molecule, selectively inhibits aldosterone synthase (CYP11B2) — the enzyme responsible for aldosterone production — without affecting cortisol levels. It has a half-life of approximately 26–30 hours and demonstrated durable effects on blood pressure in prior studies. Beyond hypertension, baxdrostat is also being investigated as monotherapy for primary aldosteronism and in combination with dapagliflozin for chronic kidney disease and heart failure prevention.

The new data from Bax24 will be shared with regulatory authorities globally and presented in a late-breaking session at the American Heart Association (AHA) Scientific Sessions in November 2025.

SOURCE: AstraZeneca