Double-blind, placebo- and active-controlled, randomized, single-ascending dose study to investigate the tolerability, safety, pharmacokinetics, and pharmacodynamics of ACT-462206 in healthy male subjects

- Signed informed consent prior to any study-mandated procedure.;- Healthy male subjects aged between 18 and 45 years (inclusive) at screening.;- Hematology, clinical chemistry, and urinalysis results not deviating from the normal range to a clinically relevant extent at screening.;- No clinically significant findings on physical examination at screening.;- Body mass index (BMI) between 18.0 and 28.0 kg/m2 (inclusive) at screening.;- Systolic blood pressure (SBP) 100-145 mmHg, diastolic blood pressure (DBP) 50-90 mmHg, and heart rate (HR) 45-90 bpm (inclusive) measured at screening on the dominant arm after 5 minutes in supine position.;- 12-lead electrocardiogram (ECG) without clinically relevant abnormalities in supine position at screening.;- Negative results from urine drug screen at screening.;- Ability to communicate well with the investigator in the local language, and to understand and comply with the requirements of the study.

- Previous history of fainting, collapse, syncope, orthostatic hypotension, or vasovagal reactions.;- Veins unsuitable for intravenous (i.v.) puncture on either arm (e.g., veins that are difficult to locate, access or puncture, veins with a tendency to rupture during or after puncture).;- Treatment with any prescribed medications (including vaccines) or over-the-counter (OTC) medications (including herbal medicines such as St John*s Wort) within 2 weeks prior to (first) study drug administration.;- Treatment with another investigational drug within 3 months prior to screening or having participated in more than four investigational drug studies within 1 year prior to screening.;- History or clinical evidence of alcoholism or drug abuse within the 3-year period prior to screening.;- History or clinical evidence of any disease, and/or existence of any surgical or medical condition, which might interfere with the absorption, distribution, metabolism or excretion of the study drugs.;- Excessive caffeine consumption, defined as >= 800 mg per day at screening.;- Smoking within 3 months prior to screening and inability to refrain from smoking during the course of the study (from screening to End-of-Study [EOS]).;- Loss of 250 mL or more of blood, or an equivalent amount of plasma, within 3 months prior to screening.;- Positive results from the hepatitis serology, except for vaccinated subjects or subjects with past but resolved hepatitis, at screening.;- Positive results from the HIV serology at screening.;- Known hypersensitivity to any excipients of the drug formulations.;- Modified Swiss Narcolepsy Scale total score < 0 or history of narcolepsy or cataplexy. ;- Any circumstances or conditions, which, in the opinion of the investigator, may affect full participation in the study or compliance with the protocol.;- Legal incapacity or limited legal capacity at screening.