Preventing Extension of Oligoarticular Juvenile Idiopathic Arthritis JIA (Limit-JIA)

Part I enrolled participants into a randomized open-label multicenter trial with a planned sample size of 306 JIA participants recruited from CARRA Registry sites. Participants were randomly allocated (1:1) to receive 24 weeks of abatacept plus usual care or usual care alone. Upon completion of 24 weeks of randomized treatment, each participant was to receive usual care and undergo follow-up for assessment of outcomes for an additional 12 months. Planned duration of the study for each participant was 18 months. Due to slow accrual and apparent loss of equipoise, enrollment into Part I was discontinued. Part I participants continued follow-up as planned.

Part II is a non-randomized continuation of LIMIT-JIA with planned enrollment of 89 to reach 80 evaluable participants receiving to the abatacept arm. Participants will now receive 24 doses of abatacept plus usual care. Upon completion of 24 doses of treatment, each participant will receive usual care and undergo follow-up for assessment of outcomes for an additional 6 months. Planned duration of the study for each participant is 12 months. Part II will assess the efficacy of abatacept in prevention of disease extension by comparison of outcomes between participants enrolled in the abatacept arm and CARRA Registry patients who would have met major eligibility criteria for LIMIT-JIA.

To be eligible for this trial, participants must meet all of the following criteria in order to be include in the study:

• Age ≥ 2 years old and ≤16.5 years old
• Clinical diagnosis of JIA by a pediatric rheumatologist within the past 6 months
• Arthritis affecting ≤4 joints between disease onset and enrollment
• Enrollment in the CARRA Registry
• Participants of childbearing potential must agree to remain abstinent or agree to use an effective and medically acceptable form of birth control from the time of written or verbal assent to at least 66 days after taking the last dose of study drug.
• Weight ≥50 kg (Canadian Sites only) ¹ Enrollment is defined as having signed consent to participate in the Limit-JIA study.

The presence of any of the following will exclude a study participant from inclusion in the study:

• 1. Systemic JIA as defined by 2004 ILAR criteria1
• Sacroiliitis (clinical or radiographic)
• Inflammatory bowel disease (IBD)
• History of psoriasis or currently active psoriasis
• History of uveitis or currently active uveitis
• Prior treatment with systemic medication(s) for JIA (e.g. one or more of the following: DMARD or biologic medication)
• Current or previous (within 30 days of enrollment) treatment with systemic glucocorticoids (A short course of oral prednisone [≤ 14 days] is allowed)
• History of active or chronic liver disease
• Chronic or acute renal disorder
• AST (SGOT), ALT (SGPT) or BUN >2 x ULN (upper limit of normal) or creatinine >1.5 mg/dL or any other laboratory abnormality considered by the examining physician to be clinically significant within 2 months of the enrollment visit
• Presence of any medical or psychological condition or laboratory result which would make the participant, in the opinion of the investigator, unsuitable for the study
• Participation in another concurrent clinical interventional study within 30 days of enrollment
• Known positive human immunodeficiency virus (HIV)
• Received a live virus vaccine within 1 month of the baseline visit
• Current or prior positive Purified Protein Derivative (PPD) test or Quantiferon Gold TB
• Pregnant, breast feeding, or planned breast feeding during the study duration
• Planned transfer to non-participating pediatric rheumatology center or adult rheumatologist in the next 12 months
• Active malignancy of any type or history of malignancy
• Chronic or active infection or any major episode of infection requiring hospitalization or treatment with intravenous (IV) antibiotics within 30 days or oral antibiotics within 14 days prior to screening
• Primary language other than English or Spanish
• Positive for Hepatitis B surface antigen or core antibody
• <10 Kg in weight
• If a potential subject has symptoms consistent with COVID-19 and/or known COVID-19 exposure at screening, it is recommended that the site follow CDC guidance regarding testing and quarantine requirements. The subject can be re-screened when there is no longer concern for active infection. A subject with a positive COVID -19 test may be re-screened.