An Efficacy, Safety, Tolerability and Dose Finding Study of XXB750 in Resistant Hypertension Patients.

Inclusion Criteria:

1. Male and female participants who are ≥ 18 years old.

2. Signed informed consent prior to participation in the study.

3. Apparent rHTN at screening (Visit 1) defined as uncontrolled BP with an office msSBP ≥ 140 mmHg despite treatment with stable (i.e., unchanged for ≥4 weeks), optimal ormaximally tolerated doses of three or four antihypertensive drugs of differentclasses, including an ACEI/ARB, a long-acting dihydropyridine CCB, and a thiazide orthiazide-like diuretic. Participant with documented intolerance to any doses of CCBsmay be eligible if receiving another class of antihypertensive medication at anoptimal or maximally tolerated dose (referred to as triple backgroundantihypertensive therapy. An optimal dose is defined as the highest dose taking into account participant's documented comorbidities and tolerability perinvestigator's clinical judgment.

4. Mean 24hr SBP ≥135 mmHg (measured by ABPM) at the end-of Run-in-Visit (Visit 30) ontreatment with optimal or maximally tolerated doses of an ACEI/ARB, a long-actingdihydropyridine CCB (or a suitable alternative in case of intolerance per inclusioncriterion above), and a thiazide or thiazide-like diuretic.

Exclusion Criteria:

1. Subjects with the following blood pressures at the specified time points are noteligible to participate in the study:

2. Office msSBP <140 mmHg at Visit 20 OR

3. Office msSBP ≥180 mmHg or office msDBP ≥110 mmHg at the end-of-run-in visit (Visit 30) OR

4. 24h mean SBP >170 mmHg or 24h mean DBP >105mmHg measured by ABPM at the end ofthe run-in (Visit 30).

5. Known history of secondary hypertension (moderate-to-severe obstructive sleep apneawithout receiving CPAP therapy (either face mask or nasal device), renovascularhypertension, primary aldosteronism, pheochromocytoma, Cushing syndrome, aorticcoarctation or other cause of secondary hypertension).

6. Estimated GFR <30 mL/min/1.73m2 using CKD-Epi equation at screening (Visit 1) or atend-of-run-in visit (Visit 30).

7. Serum potassium >5.0 mmol/L (or equivalent plasma potassium value) at screening orend-of-run-in visit (Visit 30).

8. Current therapy with a mineralocorticoid receptor antagonist (MRA) orsacubitril/valsartan or received an MRA or sacubitril/valsartan within the 4 weeksprior to screening.

9. Type I diabetes mellitus or uncontrolled Type II diabetes (defined as a plasma HbA1c ≥9%)

10. Clinically significant cardiac arrhythmias (e.g., ventricular tachycardia),high-grade AV block (e.g., Mobitz type II and third-degree AV block in absence of apacemaker) within 6 months of screening according to investigator's judgement.

11. Chronic non-paroxysmal atrial fibrillation.

12. Acute myocardial infarction (AMI) or unstable angina, or any history of ischemic orhemorrhagic stroke within 12 months of screening; or any percutaneous coronaryintervention (PCI) or coronary artery bypass graft (CABG) within 12 months ofscreening

13. History of a renal denervation procedure.

14. Mid-arm circumference ≥44 cm. The cuff should snugly fit on the arm with out themargins of cuff overhanging arm musculature.

15. Patients with history of hospitalisation for hypertensive emergencies characterisedby severe hypertension (usually grade 3) associated with funduscopic changes (flamehaemorrhages and/or papilloedema), microangiopathy, disseminated intravascularcoagulation, encephalopathy, acute aortic dissection, acute myocardial ischaemia, oracute heart failure any time prior to screening or hospitalisation fornon-emergent/non-urgent uncontrolled hypertension without target organ damage within 3 months prior to screening

16. Receiving more than 4 antihypertensive medications.

17. Night shift workers.

18. History of presence of any other disease where the life expectancy is less than 3years.

19. History of malignancy of any organ system (other than localized basal or squamouscell carcinoma of the skin or localized prostate cancer), treated or untreated,within the past 3 years, regardless of whether there is evidence of local recurrenceor metastases.

20. Evidence of hepatic disease as determined by any one of the following: SGOT (AST) orSGPT (ALT) values exceeding 3x the upper limit of normal (ULN), or bilirubin >1.5mg/dl at Visit 1.

21. Use of other investigational drugs at the time of enrollment, or within 30 days or 5half-lives of enrollment, whichever is longer.

22. History of drug abuse or alcohol dependency.

23. Lacking the ability to comprehend or follow instructions, or for any reason in theopinion of the investigator, a participant that would be unlikely or unable tocomply with study protocol.

24. Concurrent enrollment in any other investigational drug or device trial (participation in non-interventional registries is acceptable).

25. Requiring prolonged/regular use of NSAIDs except for prophylactic use of low doseaspirin up to 325 mg QD or other prohibited medications during of the study (i.e.,required use for longer than 1 week).

26. Pregnant, nursing or planning to become pregnant (documented negative pregnancy testrequired within a maximum of 7 days prior to enrollment of all women of childbearingpotential). Documentation of highly effective contraception is also required forwomen of childbearing potential (see below). Women of child-bearing potential, defined as all women physiologically capable ofbecoming pregnant, unless they are using highly effective methods of contraceptionwhile taking study treatment and for 3 months after stopping medication. Highlyeffective contraception methods include:

• Total abstinence (when this is in line with the preferred and usual lifestyleof the participant. Periodic abstinence (e.g. calendar, ovulation,symptom-thermal, post-ovulation methods) and withdrawal are not acceptablemethods of contraception.

• Female sterilization (have had surgical bilateral oophorectomy with or withouthysterectomy), total hysterectomy, or bilateral tubal ligation at least sixweeks before taking study treatment. In case of oophorectomy alone, only whenthe reproductive status of the woman has been confirmed by follow-up hormonelevel assessment.

• Male sterilization (at least 6 months prior to screening). For femaleparticipants on the study, the vasectomized male partner should be the solepartner for that participant.

• Use of oral, (estrogen and progesterone), injected, or implanted hormonalmethods of contraception or placement of an intrauterine device (IUD) orintrauterine system (IUS), or other forms of hormonal contraception that havecomparable efficacy (failure rate < 1%), for example hormone vaginal ring ortransdermal hormone contraception. In case of use of oral contraception women should have been stable on the same pillfor a minimum of 3 months before taking study treatment. Women are considered post-menopausal if they have had 12 months of natural (spontaneous) amenorrhea with an appropriate clinical profile (e.g., age-appropriatehistory of vasomotor symptoms). Women are considered not of childbearing potentialif they are post-menopausal or have had surgical bilateral oophorectomy (with orwithout hysterectomy), total hysterectomy or bilateral tubal ligation at least sixweeks ago. In the case of oophorectomy alone, only when the reproductive status ofthe woman has been confirmed by follow-up hormone level assessment is she considerednot of child bearing potential. If local regulations deviate from the contraception methods listed above to preventpregnancy, local regulations apply and will be described in the ICF.

24. History of hypersensitivity to any of the study drugs, excipients or drugs ofsimilar class.