New drug could be cure for common cause of high blood pressure
A new drug called baxdrostat has stunned doctors by reversing a common cause of high blood pressure for up to two years after patients stopped taking it.
More than a billion people worldwide have high blood pressure, or hypertension, including more than 12 million in the UK. In five to 10 per cent of cases, the condition is caused by small nodules or benign tumours on the adrenal glands that cause them to overproduce a hormone called aldosterone.
The excess hormone raises blood pressure by signalling the kidneys to retain salt. The standard treatment for what is called primary aldosteronism is to surgically remove the affected adrenal gland, but other factors can contribute to the patient’s hypertension, meaning surgery is not always a complete cure.
Baxdrostat is known as an aldosterone synthase inhibitor (ASI) which suppresses the blood pressure-raising hormone. The drug was approved in the US earlier this year for patients with hypertension that is not controlled by existing drugs.
The potentially curative effect of baxdrostat came to light in a small study that followed 14 patients whose hypertension improved dramatically during a three-month trial of the drug. They continued taking the daily pills for six to 12 months and then stopped.
When doctors checked the patients up to two years later, their blood pressure was still lower. Details are published in the New England Journal of Medicine.
Just under a quarter of the patients came off all treatment and had completely normal blood pressure.
Prof Morris Brown, a hypertension specialist at Queen Mary University of London, who led the study, said it was very exciting to see the results.
Mason Freeman, a professor of medicine at Harvard University, who was involved in the work, said it was too early to say if some of the patients were cured and a larger trial was under way to find out.
If this effect is common and very persistent then the approach to diagnosing and treating these patients is likely to dramatically change.
Brown suspected the drug might cure primary aldosteronism because of an experiment in mice 20 years ago. It showed that deleting the gene needed to make aldosterone led to the loss of cells that churned out the hormone.
He suspects baxdrostat has a similar effect. When the drug suppresses aldosterone it causes a surge in highly active molecules called reactive oxygen species. These may selectively destroy the cells that overproduce the hormone.
Those oxygen radicals are killing the cells and they disappear.
The drug is being assessed by the National Institute for Health and Care Excellence (Nice), which could make the drug available through the NHS next year.
Prof Morris Brown said the mechanism is testable and they are doing now in the laboratory.
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