Eligibility Criteria:
Inclusion Criteria:
* Signed, dated written informed consent prior to any study procedure.
* Ability to communicate well with the investigator in local language, and to understand and comply with the requirements of the study.
* Women of childbearing potential must have had a negative serum pregnancy test at screening and a negative serum pregnancy test on Day -1. Women of childbearing potential must have consistently and correctly used a reliable method of contraception with a failure rate of \< 1% per year, been sexually inactive, or have vasectomized partner.
* Healthy based on medical history and assessments performed at screening and on Day -1.
* Body mass index ≥ 18.5 and ≤ 32 kg/m\^2 at screening. Body weight at least 50 kg.
* Negative results from urine drug screen at screening and on Day -1 and negative urine alcohol test on Day -1.
* Willing to refrain from alcohol consumption from at least 48 hours prior to clinic admission to the end of study.
* Systolic blood pressure 90-145 mmHg, diastolic blood pressure 50-90 mmHg, and pulse rate 45-90 beats per minute, at screening and Day -1.
* Hematology, blood chemistry, and urinalysis results not deviating from the normal range to a clinically relevant extent at screening and Day -1.
Exclusion Criteria:
* Known hypersensitivity to selexipag, moxifloxacin, or excipients of the drug formulations used in this study.
* Treatment with selexipag or an investigational drug prior to screening within 30 days or 6 half-lives, whichever was longer.
* History or clinical evidence of any disease and/or the existence of any surgical or medical condition, which might interfere with the absorption, distribution, metabolism, or excretion of selexipag and moxifloxacin.
* Caffeine consumption of equal to or greater than 800 mg per day at screening.
* History of fainting, collapse, syncope, blackouts, orthostatic hypotension, or vasovagal reactions.
* Chronic or relevant acute infections.
* History of relevant allergy / hypersensitivity.
* History of clinical evidence of psychiatric disease, alcoholism, or drug abuse within the 3-year period prior to screening.
* Smoking within the 3 months prior to screening and inability to refrain from smoking during the study.
* Loss of 500 mL or more of blood within 56 days prior to screening.
* Positive results from the hepatitis serology, except for vaccinated subjects at screening.
* Positive results from human immunodeficiency virus serology at screening.
* Previous treatment with any prescribed or over-the-counter medications, with the exception of contraceptives and hormone replacement therapy, within the 2 weeks prior to first study drug administration or 5 half-lives, whichever longer.
* Excessive physical activities within 1 week prior to administration of study drug.
* Any cardiac condition (including ECG abnormalities) or illness with a potential to increase the cardiac risk of the subject or that may affect QTc analysis.
* QTc \> 450 ms or \> 470 ms for male or female subjects, respectively, at screening and Day -1.
* Clinically relevant abnormalities on ECG, at screening and Day -1.
* Personal or family history of long QT syndrome or hypokalemia.
* Legal incapacity or limited legal capacity.
* Veins unsuitable for intravenous puncture on either arm.
* Any circumstances or conditions, which, in the opinion of the investigator, may affected the subject's participation in the study or compliance with the protocol.
* Pregnant or nursing women.
* Women who plan to become pregnant within 1 month of the end of study.