Inclusion Criteria:  Clinical diagnosis of nonsegmental vitiligo. History of prior vitiligo treatment with a total duration of at least 3 months. 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 Further inclusion criteria apply.  Exclusion Criteria:  Other forms of vitiligo (eg, segmental) or other skin depigmentation disorders. Uncontrolled thyroid function at screening as determined by the investigator. Women who are pregnant (or who are considering pregnancy) or lactating. Medical history including thrombocytopenia, coagulopathy or platelet dysfunction, Q-wave interval abnormalities, current or history of certain infections, cancer, lymphoproliferative disorders and other medical conditions at the discretion of the investigator. Have evidence of active or latent or inadequately treated infection with Mycobacterium tuberculosis. Participants known to be infected with HIV, Hepatitis B, or Hepatitis C. Laboratory values outside of the protocol-defined ranges. Further exclusion criteria apply.