This is a Phase III, multicenter, randomized, double-blind, placebo-controlled, parallel group study to evaluate the safety, tolerability and the effect of 2 mg Baxdrostat vs. placebo, administered QD orally, on the reduction of SBP, measured by average 24-hour ABPM in 212 participants with rHTN (defined as seated SBP ≥ 140 mmHg at Screening and mean ambulatory SBP ≥ 130 mmHg at baseline, despite a stable regimen of ≥ 3 antihypertensive agents, one of which is a diuretic).

This is a Phase III, multicentre, randomised, double-blind, placebo-controlled, parallel group study to evaluate the safety, tolerability and the effect of 2 mg baxdrostat versus placebo, administered once a day (QD) orally, on the reduction of ambulatory SBP in participants with rHTN, defined as BP targets not being achieved in an individual despite the use of at least 3 antihypertensive agents of different classes (at maximum tolerated dose in the judgement of the Investigator), one of which is a diuretic.

Inclusion Criteria:

• Participant must be ≥ 18 years old, at the time of signing the informed consent.
• Mean seated SBP on AOBPM of ≥ 140 mmHg and < 170 mmHg at Screening.
• Have a stable regimen of ≥ 3 antihypertensive medications, from different therapeutic classes (at least one must be a diuretic), at maximum tolerated dose in the judgement of the Investigator, for at least 4 weeks prior to screening. Beta blockers used to treat other conditions (ie, migraine, HF, coronary artery disease) should not be counted as an antihypertensive medication for the purpose of qualifying for this study.
• Have eGFR ≥ 45 mL/min/1.73 m2 at Screening.
• Serum potassium (K+) level ≥ 3.5 and < 5.0 mmol/L at Screening, determined as per central laboratory
• Randomization Criteria: mean ambulatory SBP of ≥ 130 mmHg at randomisation.

Exclusion Criteria:

• Mean seated SBP on AOBPM ≥ 170 mmHg.
• Mean seated DBP on AOBPM ≥ 110 mmHg.
• Serum sodium level < 135 mmol/L at Screening, as per central laboratory.
• Participant has the following known secondary causes of hypertension: renal artery stenosis, uncontrolled or untreated hyperthyroidism, uncontrolled or untreated hypothyroidism, pheochromocytoma, Cushing's syndrome, aortic coarctation.
• New York Heart Association functional HF class IV.
• Persistent atrial fibrillation.

Qualified researchers can request access to anonymized individual patient-level data from AstraZeneca group of companies sponsored clinical trials via the request portal Vivli.org. All requests will be evaluated as per the AZ disclosure commitment:

https://astrazenecagrouptrials.pharmacm.com/ST/Submission/Disclosure.

"Yes", indicates that AZ are accepting requests for IPD, but this does not mean all requests will be approved.

AstraZeneca will meet or exceed data availability as per the commitments made to the EFPIA/PhRMA Data-Sharing Principles. For details of our timelines, please refer to our disclosure commitment at:

https://astrazenecagrouptrials.pharmacm.com/ST/Submission/Disclosure.

When a request has been approved AstraZeneca will provide access to the anonymized individual patient-level data via secure research environment Vivli.org. A Signed Data Usage Agreement (non-negotiable contract for data accessors) must be in place before accessing requested information.