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

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.