The objective of this study is to evaluate the tolerability, safety, and pharmacokinetics after multiple-dose administration of aprocitentan (25 mg) in healthy Japanese and Caucasian subjects.

Inclusion Criteria:

• Subjects must be of Caucasian or Japanese ethnicity
• Signed informed consent in a language understandable to the subject prior to any study-mandated procedure
• Body mass index (BMI) of 18.0 to 28.0 kg/m2 (inclusive) at Screening
• Systolic blood pressure 100-145 mmHg, diastolic blood pressure 50-90 mmHg, and pulse rate 45-90 bpm (inclusive), measured on the same arm, after 5 min in the supine position at Screening
• A woman of childbearing potential is eligible only if the following applies:

Negative serum pregnancy test at Screening,

Negative urine pregnancy test on Day -1,

Agreement to consistently and correctly use a reliable method of contraception from Screening up to at least 30 days after last study treatment administration

Japanese subjects only

• Subjects must be of native Japanese descent (all parents/grandparents of Japanese descent).
• Subjects must not have been away from Japan for more than 10 years (at Screening visit).
• Subject's lifestyle should not have changed significantly since relocation from Japan

Exclusion Criteria:

• Previous exposure to aprocitentan and/or macitentan.
• Known hypersensitivity to aprocitentan or treatments of the same class, or any of the excipients
• Pregnant or lactating women
• Any circumstances or conditions, which, in the opinion of the investigator, may affect full participation in the study or compliance with the protocol