A Study to Assess the Safety, Tolerability, Pharmacokinetics, and Pharmacodynamics of Single Ascending Doses of ACT-1004-1239 in Healthy Male Subjects

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 55 years (inclusive) at Screening.
• No sperm donation from (first) study treatment administration up to at least 90 days after (last) study treatment administration.
• Sexual abstinence or use of condoms from (first) treatment administration up to at least 90 days after (last) study treatment administration. Moreover, the female partner of childbearing potential must use a highly effective method of contraception.

Exclusion criteria

• Any circumstances or conditions, which, in the opinion of the investigator, may affect full participation in the study or compliance with the protocol.
• Any previous and/or ongoing relevant immune-related disorder or any evidence for immune dysfunction based on medical history and laboratory tests at Screening
• Any cardiac condition or illness (including clinically relevant 12-lead ECG abnormalities) with a potential to increase the cardiac risk of the subject based on medical history and 12-lead ECG measured at Screening.
• QT interval corrected with Fridericia's formula (QTcF) > 430 ms, respectively, QRS interval > 110 ms, PR interval > 200 ms, or heart rate (HR) > 90 bpm on 12-lead ECG at Screening and Day 1 pre-dose (of the first period when applicable).
• Treatment with another investigational treatment within the 2 months prior to Screening or participation in more than 3 investigational treatment studies within the year prior to Screening.
• History or clinical evidence of any disease and/or existence of any surgical or medical condition that might interfere with the ADME of the study treatment (e.g., appendectomy and herniotomy allowed, cholecystectomy not allowed).
• Previous treatment with any prescribed medications (including vaccines and strong CYP3A4 inhibitors/inducers) or over-the-counter (OTC) medications (including homeopathic preparations, herbal medicines, vitamins, and minerals) within the 2 weeks or 5 terminal half-lives (t½; whichever is longer) prior to (first) study treatment administration.