The American College of Cardiology/American Heart Association defines resistant hypertension (RH) as a clinical blood pressure (BP) reading of >130/80 mmHg in patients taking three antihypertensive drugs, including a renin–angiotensin system inhibitor, a calcium channel blocker (CCB), and a diuretic at well-tolerated doses.1, 2 It is reported from multiple population-based surveys that in the United States, there is an approximately 12%–15% prevalence of RH among adults diagnosed with hypertension.2 A prospective study demonstrates that 20% of people diagnosed with RH had primary hyperaldosteronism.3, 4 In addition to the classic three antihypertensive drugs, spironolactone and mineralocorticoid are also administered for RH. However, with respect to the safety profile of spironolactone, it has been reported to have several side effects such as low testosterone production, menstrual irregularities, and excessively raised serum potassium levels, leaving the drug unfit for the longitudinal therapeutic purpose of treating RH.5
Clinical research has demonstrated that aldosterone synthesis inhibitors lower circulating aldosterone levels by directly blocking the synthesis of aldosterone rather than blocking its receptor activity, subsequently lowering BP.6 The first aldosterone synthase inhibitor to be developed was Osilodrostat (LCI699), which was intended to reduce serum aldosterone levels and manage hypertension. It was soon discovered, nevertheless, that Osilodrostat also inhibits 11-beta hydroxylase (CYP11B1), which lowers serum cortisol levels.7
Perhaps due to decreased cortisol levels, there were many reasons for the administration of Osilodrostat; thus, what was needed for the resistance was a selective aldosterone inhibitor, which was conceived and licensed by CinCor Pharma Inc. Baxdrostat, a drug in phase 2 clinical trials, exemplifies exceptional selective suppression of aldosterone synthase without blocking 11-beta hydroxylase.8
Animal model studies conducted on cynomolgus monkeys suggested that this drug inhibits the production of aldosterone without influencing the increase in cortisol caused by adrenocorticotropic hormone.9 Furthermore, research involving healthy volunteers validated these findings (ClinicalTrials.gov Identifier: NCT01995383).8 Multiple ascending doses of Baxdrostat were later investigated for safety, pharmacokinetics, and pharmacodynamics in a Phase I trial, which found that Baxdrostat was well tolerated, safe, and caused a dose-dependent decrease in plasma aldosterone but not cortisol.
Baxdrostat was tested in a Phase II trial8, 10 that was randomized, double-blind, placebo-controlled, and dose-ranging in adults with treatment-resistant hypertension (Brig