A Rollover Study to Provide Continued Treatment for Participants Previously Enrolled in Studies of Itacitinib

This is a mutli-center open-label study to provide continued supply of itacitinib to participants from the following Incyte-sponsored studies of itacitinib: INCB39110-209, INCB39110-213, INCB39110-214, INCB39110-230, and 39110-309. Eligible participants will receive treatment with itacitinib as per the treatment dose and schedule they received in the study in which they were originally enrolled. The original study is referred to as the "parent protocol". Participants who receive itacitinib in this study may continue treatment as long as the regimen is tolerated, the participant is deriving clinical benefit (in the opinion of the investigator), and the participant does not meet discontinuation criteria.

Inclusion Criteria: * Currently enrolled and receiving treatment in an Incyte-sponsored itacitinib (INCB39110)-based clinical study (parent Protocol). * Currently tolerating treatment as defined by the parent Protocol. * Currently receiving clinical benefit from itacitinib-based treatment, as determined by the investigator. * Has demonstrated compliance, as assessed by the investigator, with the parent protocol requirements. * Willingness and ability to comply with scheduled visits, treatment plans, and any other study procedures indicated in this Protocol. * Willingness to avoid pregnancy or fathering children.. * Ability to comprehend and willingness to sign an ICF. Exclusion Criteria: * Able to access itacitinib therapy commercially. * Participants with an uncontrolled intercurrent illness or any concurrent condition that, in the investigator's opinion, would jeopardize the safety of the participant or compliance with the Protocol. * Pregnant or breastfeeding women.