Pharmacokinetic Interaction Between Diltiazem and ACT-541468 in Healthy Subjects

A Single-center, Open-label, Randomized, Two-way Crossover Study to Investigate the Effect of Multiple-dose Diltiazem on the Pharmacokinetics of a Single Dose of 25 mg ACT-541468 in Healthy Male Subjects

The main objective of this study is to investigate whether repeated administration of a cardiac medication (diltiazem) can affect the pharmacokinetics (i.e., amount and time of presence in the blood) of ACT-541468

Because ACT-541468 appears to be mainly metabolized by CYP3A4, it is deemed of interest to investigate the potential influence of diltiazem, a well-known CYP3A4 inhibitor on the pharmacokinetic profile of ACT-541468.

Safety of the concomitant administration of the two drugs will also be assessed

Inclusion Criteria:

• Signed informed consent
• Body mass index (BMI) between 18.0 and 28.0 kg/m2 (inclusive) at screening
• Healthy on the basis of physical examination,cardiovascular assessments and laboratory tests

Exclusion Criteria:

• Any contraindication to the study drugs
• History or presence of any disease or condition or treatment, which may put the subject at risk of participation in the study or may interfere with the absorption, distribution, metabolism or excretion of the study drugs
• History of narcolepsy or cataplexy or modified Swiss narcolepsy scale total score < 0
• Any circumstances or conditions, which, in the opinion of the investigator, may affect the subject's full participation in the study or compliance with the protocol