A new treatment for high blood pressure can provide continuous, round-the-clock blood pressure control for people whose condition is hard to treat, according to a global study led by a UCL professor.
The treatment, baxdrostat, works by reducing levels of aldosterone, a hormone that can drive high blood pressure in some people.
The findings build on results from a related study from the same team, published earlier this year in the New England Journal of Medicine. That study showed that the drug can lower blood pressure in people with stubbornly high blood pressure, when measured during a clinic visit.
The latest trial - called Bax24 - shows that this effect can be sustained over 24 hours.
The Bax24 trial involved 218 people from 79 locations worldwide who had treatment-resistant hypertension - meaning their blood pressure remained high despite taking at least three different medications. The study was led globally by Professor Bryan Williams (UCL Institute of Cardiovascular Science) and sponsored by AstraZeneca.
Participants took either baxdrostat or a placebo once daily in tablet form, alongside their usual treatment.
Blood pressure was measured using 24-hour ambulatory blood pressure monitoring (ABPM), where a small wearable device records blood pressure regularly throughout the day and night. This method provides a more accurate picture of blood pressure control than a clinic reading, and is a stronger predictor of heart attack, stroke and risk of death.
The results - presented at a late breaking science session at the American Heart Association Scientific Sessions in New Orleans - showed that 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 results support and strengthen those of the earlier trial, called BaxHTN, also led by Professor Williams, published in August. In that study, which involved nearly 800 patients, baxdrostat lowered blood pressure by around -10 mmHg more than placebo, a reduction known to meaningfully lower cardiovascular risk, and helped twice as many participants reach healthy blood pressure levels, compared with placebo. In BaxHTN, blood pressure was measured at a point in time in the clinic.
Professor Williams said: "For millions of people, high blood pressure is difficult to control, even with multiple medications. Persistent high blood pressure massively increases the risk of heart disease, stroke, and kidney disease.
"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 24hr period. The effectiveness of this drug 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."
Sharon Barr, Executive Vice President, BioPharmaceuticals R&D at AstraZeneca, 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."
Professor Williams's research on both the BaxHTN and Bax24 trials was supported by the NIHR Biomedical Research Centre at UCLH. Baxdrostat is licensed to AstraZeneca.
