Inclusion Criteria:

•     Aged ≥ 18 years.

    Clinical diagnosis of nonsegmental vitiligo and meet the following: 
- Agreement to discontinue all agents and procedures used to treat vitiligo from screening through the final safety follow-up visit.
-Willingness to avoid pregnancy or fathering children.

Exclusion Criteria:

•     Other forms of vitiligo or skin depigmentation disorders.
•     Clinically significant abnormal TSH or free T4 at screening.
•     Use of laser or phototherapy within 8 weeks and dihydroxyacetone within 4 weeks prior to Day 1.
•     Current or past use of the depigmenting agent monobenzyl ether of hydroquinone including Benoquin®.
•     History of melanocyte-keratinocyte transplantation procedure or other surgical treatment for vitiligo.
•     Spontaneous and significant repigmentation within 6 months prior to screening.
•     Women who are pregnant, considering pregnancy, or breast feeding.
•     Medical history including thrombocytopenia, coagulopathy or platelet dysfunction; venous and arterial thrombosis, deep vein thrombosis, pulmonary embolism, stroke, moderate to severe heart failure, cerebrovascular accident, myocardial infarction, or other significant cardiovascular diseases; Q-wave interval abnormalities; disseminated herpes zoster or recurrent dermatomal herpes zoster; disseminated herpes simplex; chronic/recurrent infections; malignancies.
•     Evidence of infection with TB, HBV, HCV or HIV.
•     History of failure to JAK inhibitor treatment of any inflammatory disease.
•     Laboratory values outside of the protocol-defined ranges.

Other protocol-defined Inclusion/Exclusion Criteria may apply.