Rollover Study for Participants Previously Enrolled in Clinical Trials of Povorcitinib

Inclusion Criteria:

• Ability to comprehend and willingness to sign a written ICF for the study.

• Completed the treatment period of a predetermined, Incyte-sponsored, povorcitinibparent study without safety or tolerability concerns, per investigator's assessment.

• Received clinical benefit from treatment with study drug during the parent study, asdetermined by the investigator.

• Demonstrated compliance, as assessed by the investigator, with the parent Protocolrequirements.

• Willingness to avoid pregnancy or fathering children as defined in the protocol.

• Willingness and ability to comply with the study Protocol and procedures.

Exclusion Criteria:

• Had been permanently discontinued from study treatment during the parent study.

• Had temporary study drug interruption due to safety and/or efficacy reasons at orafter the final visit of the parent study.

• Received at least 1 dose of either of the following therapies within the 28 daysprior to starting treatment in this rollover study:

• Biologic immunomodulator (examples include but are not limited to adalimumab,bimekizumab, dupilumab, infliximab, nemolizumab, secukinumab).

• Live, attenuated vaccine.

• Plans for administration of a live, attenuated vaccine during this study or within 8weeks after the last dose of study drug.

• Women who are pregnant (or who are considering pregnancy) or breastfeeding.

• Known hypersensitivity or severe reaction to povorcitinib or excipients ofpovorcitinib and/or other products in the same class.

• Currently enrolled in any other clinical study involving an investigational productor any other type of medical research judged not to be scientifically or medicallycompatible with this study.

• Any condition that would, in the investigator's and/or sponsor's judgment, interferewith full participation in the study, including administration of study drug andattending required study visits; pose a significant risk to the participant; orinterfere with interpretation of study data.

Other protocol-defined Inclusion/Exclusion Criteria may apply.