A study in healthy male subjects to investigate the effect of famotidine and efavirenz on the way the body takes up, distributes, and gets rid of daridorexant.

Inclusion Criteria:

• Signed informed consent in a language understandable to the subject prior to any study-mandated procedure.
• Healthy male subjects aged between 18 and 45 years (inclusive) at Screening.

Exclusion Criteria:

• Clinically relevant findings on the physical examination at Screening.
• Clinically relevant abnormalities on 12-lead ECG, measured after at least 5 min in a supine position at Screening.
• Clinically relevant findings in clinical laboratory tests (hematology, clinical chemistry) at Screening and on Day -1.
• 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(s) (appendectomy and herniotomy allowed, cholecystectomy not allowed).
• Any circumstances or conditions, which, in the opinion of the investigator, may affect full participation in the study or compliance with the protocol.
• Moderate or severe renal insufficiency (creatinine clearance < 60 mL/min calculated with the Cockcroft Gault formula) at Screening.
• Total bilirubin > 1.5 x Upper Limit of Normal at Screening.