A Study to Evaluate the Pharmacokinetics, Safety, and Tolerability of Upadacitinib in Pediatric Subjects With Polyarticular Course Juvenile Idiopathic Arthritis
A Study to Evaluate the Pharmacokinetics, Safety, and Tolerability of Upadacitinib in Pediatric Subjects With Polyarticular Course Juvenile Idiopathic Arthritis
This is a study to evaluate pharmacokinetics, safety and tolerability of upadacitinib in
 pediatric participants with polyarticular course juvenile idiopathic arthritis. This study
 consists of two parts: Part 1 is multiple-cohort study that consists of two sequential
 multiple-ascending dose groups. Participants benefiting from the study drug with no ongoing
 adverse events of special interest or serious adverse events will have option to enroll in
 Part 2. Part 2 is open-label, long term extension study to evaluate safety and tolerability.
Inclusion Criteria:

 -  Participant have total body weight of 10 kg or higher at the time of screening.

 -  Participant diagnosed with pcJIA (rheumatoid factor-positive or rheumatoid
 factor-negative polyarticular JIA, extended oligoarticular JIA, or systemic JIA with
 active arthritis and without active systemic features) with a history of arthritis
 affecting at least 5 joints during the first 6 months of disease (for extended
 oligoarticular JIA: <=4 joints during first 6 months of disease and >4 joints
 thereafter).

 -  Participant have 5 or more active joints at the time of screening, defined as the
 presence of swollen joints (not due to deformity) or, in the absence of swelling,
 joints with the limitation of movement (LOM) plus pain on motion and/or tenderness
 with palpitation, with LOM present in at least three of the active joints.

 -  If receiving methotrexate (MTX), have been taking MTX for at least 12 weeks
 immediately before and including Study Day 1 on an stable dose of 10 to 20 mg/m2 for
 at least 8 weeks before and including Study Day 1; in addition, participants should
 take either folic acid or folinic acid according to local standard of care.

 -  If on oral glucocorticosteroids, must have been taking oral glucocorticosteroids at a
 stable dose (no greater than 10 mg/day or 0.2 mg/kg/day, whatever is lower) for at
 least 1 week before and including Study Day 1.

 Exclusion Criteria:

 -  Participant with diagnosis of enthesitis-related arthritis (ERA) or juvenile psoriatic
 arthritis (JPSA).

 -  Participant have prior exposure to JAK inhibitor.