FDA Approves Baxfendy, the First Aldosterone Synthase Inhibitor for Uncontrolled Hypertension
AstraZeneca's baxdrostat (Baxfendy) became the first aldosterone synthase inhibitor approved in the US on May 18, 2026, giving the estimated 23 million Americans whose blood pressure remains uncontrolled on two or more drugs a new mechanistic option.
Overview
The U.S. Food and Drug Administration approved Baxfendy (baxdrostat) on May 18, 2026, making it the first aldosterone synthase inhibitor ever authorized for the treatment of hypertension, according to BioSpace. The drug, developed by AstraZeneca through its 2023 acquisition of CinCor Pharma, is indicated in combination with other antihypertensive medications to lower blood pressure in adults whose condition is not adequately controlled on existing treatment. Ruud Dobber, AstraZeneca Executive Vice President, stated: “In the US, about 23 million patients are uncontrolled despite being on two or more medicines for hypertension, which is a disease that has seen little therapeutic progress for the past two decades,” per the company’s press release on BioSpace.
What We Know
The mechanism. Baxfendy is a highly selective and potent aldosterone synthase inhibitor (ASI) designed to lower blood pressure by specifically inhibiting the production of aldosterone, a hormone that raises blood pressure to unhealthy levels and increases the risk of heart and kidney problems, according to the company’s press release on BioSpace. More precisely, it inhibits an enzyme that synthesizes aldosterone — a hormone that raises blood pressure by causing the body to excrete potassium while retaining water and salt, as BioPharma Dive explained. Unlike earlier compounds that targeted aldosterone production, baxdrostat does not affect cortisol, reducing a key tolerability concern.
The pivotal BaxHTN trial. The approval rests on results from BaxHTN (NCT06034743), a phase 3, multinational, double-blind, randomized, placebo-controlled trial, per the PubMed abstract of the NEJM publication. A total of 796 patients with seated systolic blood pressure of 140 to less than 170 mm Hg despite stable dual antihypertensive therapy — or triple-plus therapy including a diuretic for those with resistant hypertension — were randomized to 1-mg baxdrostat (264 patients), 2-mg baxdrostat (266 patients), or placebo (264 patients) once daily for 12 weeks.
At week 12, absolute reductions in seated systolic blood pressure from baseline were 14.5 mm Hg (95% CI, -16.5 to -12.5) in the 1-mg arm and 15.7 mm Hg (95% CI, -17.6 to -13.7) in the 2-mg arm, compared with 5.8 mm Hg (95% CI, -7.9 to -3.8) with placebo. The placebo-adjusted differences were -8.7 mm Hg and -9.8 mm Hg respectively, with P<0.001 for both, per the NEJM PubMed abstract.
The Bax24 trial in treatment-resistant hypertension. A second Phase 3 trial, Bax24, provides complementary evidence specifically in patients already failing three or more antihypertensive medications. Published in The Lancet on March 7, 2026 (Volume 407, Issue 10532, pages 988-999; DOI 10.1016/S0140-6736(25)02549-8), Bax24 was a phase 3, randomised, double-blind, placebo-controlled trial conducted across 79 clinical sites in 22 countries. Among 217 randomised patients, baxdrostat 2 mg once daily produced a change from baseline in 24-hour ambulatory systolic blood pressure of -16.6 mm Hg (95% CI -18.8 to -14.3), versus -2.6 mm Hg (-4.7 to -0.4) with placebo; the estimated placebo-corrected difference was -14.0 mm Hg (-17.2 to -10.8; p<0.0001). Adverse events occurred in 56 (52%) of 108 patients in the baxdrostat group and 40 (37%) of 109 patients in the placebo group; a confirmed potassium level above 6 mmol/L occurred in three (3%) baxdrostat recipients and none of the placebo recipients.
Dosing and monitoring. The recommended dosage of Baxfendy is 2 mg orally once daily. For patients at increased risk of hyperkalemia or hyponatremia, the recommended dosage is 1 mg orally once daily, per the BioSpace press release. In BaxHTN, hyperkalemia occurred in 6.6% of patients at the 1-mg dose and 10.2% at the 2-mg dose, while hyponatremia was observed in 2.1% and 3.2% respectively.
Safety profile. Most adverse events in BaxHTN were classified as mild, according to BioPharma Dive. Common adverse reactions include muscle spasms, dizziness, hypotension, and abnormal sodium and potassium levels.
Significance
Hypertension affects approximately 1.4 billion people worldwide, according to BioPharma Dive, and is the leading risk factor for cardiovascular disease and premature death. Despite a large portfolio of existing drug classes, a substantial share of patients remain uncontrolled — Dobber specifically called it a disease that has seen little therapeutic progress for the past two decades.
Baxfendy comes to AstraZeneca through its 2023 acquisition of CinCor Pharma for $1.3 billion, according to BioSpace. AstraZeneca executives have said they expect the drug to generate at least $5 billion per year, with potential to reach roughly $10 billion if it succeeds in additional studies and indications, per BioPharma Dive.
What We Don’t Know
Baxdrostat’s approval is based on 12-week endpoints. Whether the blood pressure reductions are durable over years — and whether sustained aldosterone suppression carries any long-term risks beyond the potassium and sodium imbalances already identified — will require post-marketing data. The drug is currently under investigation for additional indications including primary aldosteronism (BaxPA trial), chronic kidney disease with hypertension in combination with dapagliflozin, and heart failure prevention (Prevent-HF), according to the AstraZeneca press release on BioSpace. Baxfendy is expected to become available in US pharmacies in early June 2026.