To demonstrate that multiple-dose administration of oral therapeutic and supratherapeutic doses of aprocitentan do not have a clinically relevant effect on the QT interval.

Inclusion Criteria:

• Signed informed consent in a language understandable to the subject prior to any study-mandated procedure.

• Ability to communicate well with the investigator, in a language understandable to the subject, and to understand and comply with the requirements of the study.

• No clinically significant findings on the physical examination at screening.

• Body mass index 18.0 to 30.0 kg/m2 (inclusive) at screening.

• Systolic blood pressure 90-140 mmHg, diastolic blood pressure 50-90 mmHg, and pulse rate 50-90 bpm (all inclusive), measured on the same arm, after 5 minutes in the supine position at screening.

• 12-lead safety ECG: QTcF less than 450 ms for male subjects and less than 470 ms for female subjects, QRS less than 110 ms, PR less than 220 ms, and resting HR greater than 50 bpm and less than 90 bpm with no clinically relevant abnormalities on 12-lead ECG after at least 5 min in the supine position at Screening and on Day 1 pre-dose of Period 1.

• No clinically relevant findings in clinical laboratory tests (hematology, clinical chemistry) at screening.

• Negative results from urine drug screen, urine cotinine test, and breath alcohol tests at screening and on Day -1 of each period.

• A woman of childbearing potential (WoCBP) is eligible only if the following applies:

  • Negative serum pregnancy test at screening.
  • Negative urine pregnancy test on Day -1 of each period.
  • Agreement to consistently and correctly use a highly effective method of contraception from screening up to at least 30 days after last study treatment administration in the last period with in-between periods included.

• Women of non-childbearing potential (WoNCBP) must meet at least one of the following criteria:

  • Previous bilateral salpingectomy, salpingo-oophorectomy or hysterectomy,
  • Confirmed premature ovarian failure,
  • Post-menopausal.

Exclusion Criteria:

• Pregnant or lactating women.
• Previous exposure to aprocitentan or macitentan.
• Known hypersensitivity to aprocitentan or macitentan or any of the drug product excipients, or treatments of the same class.
• Any contraindication or known hypersensitivity to moxifloxacin or any of the drug product excipients or to other fluoroquinolone antibiotics.
• Known hypersensitivity or allergy to natural rubber latex.
• History of major medical or surgical disorders which, in the opinion of the investigator, are likely to interfere with the absorption, distribution, metabolism, or excretion of the study treatment (appendectomy and herniotomy allowed, cholecystectomy not allowed).
• Acute, ongoing, recurrent, or chronic systemic disease able to interfere with the evaluation of the study.
• Previous treatment with any prescribed medications (including vaccines) or over-the-counter (OTC) medications (including herbal medicines such as St John's Wort, homeopathic preparations, vitamins, and minerals) within 2 weeks or 5 t½ (whichever is longer) prior to first study treatment administration with the exception of contraceptives in female subjects.
• History or presence of rhythm disorders (e.g., sinoatrial heart block, sick-sinus syndrome, second- or third-degree atrioventricular block, long QT syndrome, symptomatic bradycardia, atrial flutter, or atrial fibrillation) or hypokalemia.
• Legal incapacity or limited legal capacity at screening.

Placebo-controlled.