Fourteen patients with high blood pressure have remained in remission for up to three years after stopping a daily medication that killed the tumour cells causing their condition, a study published in The New England Journal of Medicine has found. The drug baxdrostat, approved in the US this year for patients whose blood pressure remains dangerously high despite taking two or more other drugs, destroyed aldosterone-producing cells in the adrenal glands, allowing the patients to stop treatment while maintaining an average 25 millimetres of mercury lower systolic blood pressure.
The finding could benefit more than one million people in Britain, where nearly a third of adults have hypertension and one in 10 cases are caused by tiny benign tumours in the adrenal glands that overproduce aldosterone, a hormone that raises blood pressure.
Baxdrostat Destroys Aldosterone-Producing Cells
The unexpected result came from an analysis of a larger trial conducted to gain approval of baxdrostat as a standard blood pressure medication taken indefinitely. At the end of the three-month approval trial, 14 patients who had experienced large improvements were allowed to continue on the drug for between six and 12 months, then stopped.
So far, their blood pressure has stayed at the lower level for up to two years of follow-up, and one patient has been off the drug for three years, according to Professor Morris Brown, a heart specialist at Queen Mary University of London who was involved in the study. The drug kills the tumour cells because blocking aldosterone production generates reactive oxygen species—energetic compounds that are very harmful to the cell, Brown said.
Surgery Currently the Only Cure
Currently, hypertension caused by these adrenal tumours can be cured by surgery to remove the affected adrenal gland, though sometimes patients do not know they have the tumours. People with “stubborn” blood pressure that does not respond to multiple drugs are more likely to have the tumours as the underlying cause.
From Chronic Treatment to Cure
“It’s very exciting,” said Brown, who predicted the benefit based on the drug’s animal trials over 10 years ago. “It’s been my hope that one day we would go from chronic treatment to cure.”
Mason Freeman, professor of medicine at Harvard Medical School who also worked on the study, said the sustained remission offers the possibility that many patients with adrenal gland tumours may be treated with a once-a-day pill for a limited period and obtain similar benefits to major adrenal surgery.
Larger Study Under Way as UK Approval Pending
A larger study is now under way to confirm the permanent cure effect. The drug is likely to become available in Britain next year under the same conditions as the US approval, with the National Institute for Health and Care Excellence currently deciding whether it will be offered on the NHS.
“Longer follow-up may justify a claim that a finite course of medication leads to infinite cure,” Brown said. “That’s the hope. Clearly we need a larger study, which is now under way, to really prove this.”
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