The primary purpose of this study is to investigate the fate of ACT-132577 in healthy subjects and in people with severe kidney disease

Inclusion Criteria:

ALL SUBJECTS:

• Signed informed consent in the local language prior to any study-mandated procedure;
• Male/female aged 18 to 65 years (inclusive) at screening;
• Body mass index of 18.0 to 32.0 kg/m2 (inclusive) at screening. Body weight at least 50 kg;
• Women of childbearing potential must have a negative serum pregnancy test and use reliable birth controls up to 30 days after the end of study treatment.

HEALTHY SUBJECTS:

• Normal renal function confirmed by the estimated glomerular filtration rate (eGFR) determined at screening;
• Healthy on the basis of physical examination, cardiovascular assessments and laboratory tests.

SEVERE RENAL FUNCTION IMPAIRMENT SUBJECTS:

- Severe renal function impairment is defined by eGFR estimated at screening between 15 mL/min/1.73 m2 and 29 mL/min/1.73 m2 (inclusive).

Exclusion Criteria:

ALL SUBJECTS:

• Pregnant or lactating women;
• Known hypersensitivity to ACT-132577 or drugs of the same class, or any of their excipients;
• Known hypersensitivity or allergy to natural rubber latex;
• Any circumstances or conditions, which, in the opinion of the investigator, may affect full participation in the study or compliance with the protocol.

SEVERE RENAL FUNCTION IMPAIRMENT SUBJECTS:

• End-stage renal disease that requires dialysis;
• Hemoglobin concentration < 9 g/dL;
• History of severe renal stenosis;
• Serum potassium concentration > 5.5 mmol/L;
• Presence of severe cardiac disease;
• History of clinically relevant bleeding disorder;
• Presence of any organ disorder, with the exception of renal function impairment, or use of any medication which might interfere with the pharmacokinetics of ACT-132577;
• Known life-threatening disease with a life expectancy of less than 1 year;
• Presence of unstable diabetes mellitus.