A major international study has shown that a new tablet treatment can substantially reduce blood pressure in patients whose levels remain dangerously high despite taking several existing medicines. The findings come from a Phase III clinical trial led by Professor Bryan Williams of UCL’s Institute of Cardiovascular Science, and they point to a potentially transformative option for people living with resistant hypertension. Globally, high blood pressure affects around 1.3 billion people, with almost half of cases either uncontrolled or resistant to treatment. In the UK alone, around 14 million people are affected, leaving millions at heightened risk of heart attack, stroke, kidney disease, and premature death.
The BaxHTN trial, sponsored by AstraZeneca and supported by the NIHR Biomedical Research Centre at UCLH, tested the drug baxdrostat in nearly 800 patients across 214 clinics worldwide. After 12 weeks, those receiving baxdrostat at doses of 1 mg or 2 mg once daily experienced an average fall in blood pressure of 9–10 mmHg more than patients taking a placebo. This reduction was not only statistically significant but also clinically meaningful, since even modest reductions in systolic blood pressure are known to lower cardiovascular risk substantially. Remarkably, about four in ten patients taking baxdrostat achieved healthy blood pressure targets, compared with fewer than two in ten in the placebo group.
Professor Williams, who is presenting the findings at the European Society of Cardiology (ESC) Congress 2025 in Madrid and in the New England Journal of Medicine, described the results as “exciting.” He emphasised that a near 10 mmHg drop in systolic blood pressure represents a significant advance, directly translating into fewer heart attacks, strokes, episodes of heart failure, and cases of kidney disease. Moreover, the treatment proved durable, with clinically meaningful blood pressure reductions sustained for up to 32 weeks and no unanticipated safety concerns observed in the study population.
Baxdrostat is the latest innovation in a long research effort to tackle one of the most difficult drivers of hypertension: excess aldosterone. This hormone regulates salt and water balance in the body. When overproduced, it forces the kidneys to retain salt and water, pushing up blood pressure and making it stubbornly resistant to control. For decades, scientists have sought practical ways to target aldosterone overproduction, with limited success. Baxdrostat works by directly blocking aldosterone production, offering a precise way to address this underlying cause in people with difficult-to-treat hypertension.
Professor Williams, Chair of Medicine at UCL, highlighted the broader significance of these findings, noting that up to half of patients on treatment may still have uncontrolled blood pressure—a figure likely higher when considering the stricter targets now set for optimal control. By effectively reducing blood pressure in resistant cases, baxdrostat provides crucial new evidence that aldosterone dysregulation is central to the condition in millions of people. Importantly, it offers hope that future care for hypertension could be much more effective, moving beyond simply adding more and more drugs to a patient’s regimen.
The global implications are profound. While hypertension was once more prevalent in higher-income Western nations, the burden has shifted dramatically to Eastern and lower-income countries as diets and lifestyles have changed. Today, more than half of all people with high blood pressure live in Asia, including 226 million in China and 199 million in India. Professor Williams concluded that the results suggest baxdrostat could help up to half a billion people worldwide—and as many as 10 million in the UK—at a time when achieving lower and healthier blood pressure targets has never been more urgent.
More information: Bryan Williams et al, Efficacy and Safety of Baxdrostat in Uncontrolled and Resistant Hypertension, New England Journal of Medicine. DOI: 10.1056/NEJMoa2507109
Journal information: New England Journal of Medicine Provided by University College London
