Dose-finding Study With ACT-132577 (Aprocitentan) in Participants With Essential Hypertension

Inclusion Criteria: * Signed informed consent prior to any study-mandated procedure * No contra-indication to stop (according to label) anti-hypertensive treatment(s) at screening * Mild-to-moderate essential hypertension with or without ongoing anti-hypertensive treatment(s): \-- Mean (of 5 measurements) sitting diastolic blood pressure (SiDBP) ≥ 90 to \< 110 mmHg measured by office blood pressure measurements (OBPM). * Women of childbearing potential must have a negative pregnancy test and use of reliable methods of contraception Exclusion Criteria: * Severe hypertension (grade 3): mean sitting systolic/diastolic BP (SiSBP/SiDBP; measured by OBPM) ≥ 180/110 mmHg, respectively. * Secondary hypertension * Known hypertensive retinopathy greater than Keith-Wagener Grade 2 * Myocardial infarction, percutaneous transluminal coronary angioplasty, or coronary artery bypass graft within 12 months prior to randomization * Unstable angina within 6 months prior to randomization * Heart failure New York Heart Association class III and IV * Valvular defects (such as severe aortic or mitral valve disease) and/or hemodynamically relevant rhythm disturbances * Clinical evidence of cerebrovascular insufficiency or a cerebrovascular accident within 6 months prior to randomization. * Subjects working night shifts * Body mass index \< 20 kg/m2 or \> 40 kg/m2 * Treatment with any medication which may affect BP (e.g., treatment of psychiatric diseases, ophthalmic preparations) * Treatment w…