A promising new medication offers hope for people struggling to control high blood pressure, even when taking several standard treatments. Findings from a major Phase III clinical study, led by Professor Bryan Williams of UCL, reveal that this latest therapy can deliver significantly improved outcomes for patients with stubbornly high hypertension.
High blood pressure, or hypertension, impacts more than 1.3 billion people worldwide. Worryingly, about half of these individuals remain unable to manage their blood pressure effectively, despite existing medications—putting them at high risk for heart attacks, strokes, kidney disease, and a shortened lifespan. In the UK alone, some 14 million people live with hypertension.
The landmark BaxHTN trial, run by Professor Williams from the UCL Institute of Cardiovascular Science, examined the effects of a new oral drug, baxdrostat. Nearly 800 participants from 214 clinics around the globe took part in the trial, testing the medicine in patients who had not responded to other therapies.
Full results were shared at the 2025 European Society of Cardiology (ESC) Congress in Madrid and featured in the New England Journal of Medicine.
After 12 weeks of treatment, those given baxdrostat at doses of 1 mg or 2 mg daily experienced a drop in blood pressure of roughly 9–10 mmHg more than patients taking a placebo—enough to meaningfully reduce the risk of cardiovascular complications. Notably, around 40% of people in the baxdrostat group reached a healthy blood pressure target, compared to less than 20% in the placebo group.
Professor Williams, who unveiled the findings at the ESC Congress, commented: “Seeing a reduction of nearly 10 mmHg in systolic blood pressure through baxdrostat in this Phase III trial is remarkable. This amount of improvement is directly linked to dramatic decreases in heart attack, stroke, heart failure, and kidney disease risk.”
Experts have long understood that the hormone aldosterone plays a fundamental role in regulating blood pressure through the kidneys’ balance of salt and water. Some individuals produce excessive aldosterone, which increases fluid retention and pushes blood pressure higher, often making hypertension much harder to manage.
Although researchers have pursued ways to address aldosterone imbalances for many years, progress has been challenging. Baxdrostat is a new class of drug that works by precisely blocking the body’s production of aldosterone, striking at a core biological driver of treatment-resistant hypertension.
Professor Williams, who is also UCL’s Chair of Medicine, added: “These results represent a real breakthrough—both for treatment options and for our comprehension of why some people struggle so much with blood pressure control.
“Nearly half of people already prescribed treatment for hypertension remain above target blood pressure levels. This figure may be conservative, especially as the recommended targets are now lower than ever.”
He continued: “For those with difficult-to-control hypertension, adding daily baxdrostat (1mg or 2mg) to their regular medication provided meaningful, lasting drops in systolic blood pressure—benefits that continued for at least 32 weeks. There were no unexpected safety concerns observed during the trial.”
“These findings suggest that excess aldosterone is a significant factor in millions of people with hard-to-control blood pressure and hint at the potential for far more effective therapies in the future.”
While hypertension was once far more prevalent in higher-income Western countries, global patterns have shifted. Now, more than half of those living with high blood pressure are in Asian and lower-income nations. Rapidly changing dietary habits—especially lower salt intake in Western diets—play a key role. In fact, an estimated 226 million people in China and 199 million in India live with hypertension.
According to Professor Williams, this new treatment could ultimately benefit as many as half a billion people around the world—and up to 10 million people in the UK alone—especially given today’s stricter goals for healthy blood pressure.
