The purpose of this study is to evaluate the effect of povorcitinib on the QT/QTc Interval in healthy participants.

Inclusion Criteria:

• Ability to comprehend and willingness to sign a written ICF for the study.
• Age 18 to 55 years inclusive at the time of signing the ICF.
• Body mass index between 18.0 and 30.5 kg/m2, inclusive.
• No clinically significant findings on screening evaluations as determined by the investigator (clinical, laboratory, and ECG).
• Ability to swallow and retain oral medication.

Exclusion Criteria:

• History of uncontrolled or unstable cardiovascular, respiratory, renal, gastrointestinal, endocrine, hematopoietic, psychiatric, and/or neurological disease within 6 months of screening. Participants with any history of myasthenia gravis will be excluded.
• Presence or history of a malabsorption syndrome possibly affecting drug absorption (eg, Crohn disease or chronic pancreatitis).
• Current or recent (within 3 months of screening) clinically significant gastrointestinal disease or surgery (including cholecystectomy and excluding appendectomy and hernia repair) that could affect the absorption of study drug or moxifloxacin.
• History of cardiovascular, cerebrovascular, peripheral vascular, or thrombotic disease or uncontrolled hypertension (systolic blood pressure > 140 mm Hg or diastolic blood pressure > 90 mm Hg at screening, confirmed by repeat testing).
• Positive test for HBV, HCV, or HIV. Participants whose results are compatible with prior immunization for or immunity due to infection with HBV may be included at the discretion of the investigator.
• History of tobacco- or nicotine-containing product-use within 1 month before screening.
• Pregnant or breastfeeding.

Other protocol-defined Inclusion/Exclusion Criteria may apply.