Long term follow-up after sudden withdrawal from a multicentric study of abatacept in juvenile idiopathic arthritis – data from the Portuguese cohort

Background

A cohort of patients participating in a multicentric, multinational phase III trial to assess the efficacy and safety of abatacept in juvenile idiopathic arthritis (JIA) were discontinued from the study due to administrative reasons.

Aim

To assess long term efficacy and monitor clinical follow up after the sudden removal of abatacept.

Methods

Patients in the open arm of the trial, receiving 10mg/kg monthly infusions of abatacept were followed for 4 years after its suspension. Outcome measures included clinical remission and disease control without biologics.

Results

Eight patients (7M/1F) with mean age of 16.5 years (range 13-19years) and disease duration of 8,6years (range 1,5-13years) were followed. All patients had polyarticular involvement only partially responsive to methotrexate (extended oligoarticular (OE)-3, polyarticular Rheumatoid factor IgM negative (Poly)-2, systemic onset (SoJIA)-3). Concurrent therapies, maintained after the abatacept trial included NSAIDS, Methotrexate (8/8) and low dose steroids (3/8).

All patients met the ACRpedi30 criteria, 5 of which (OE and Poly) were either in remission (2/8) or had marked improvement (1or 2 active joints). After 12 months of follow-up, all OE patients had inactive disease, as well as one Poly (4/8). Subsequently, 1of the OE and the other Poly flared, with etanercept being introduced at 27 and 29months of follow-up, respectively; 3 patients currently remain in full remission after 4 years (2 OE, 1 poly).

SoJIA patients maintained active disease, requiring biologic therapy (mean 18months).

Conclusion

Although it’s a small cohort, this study suggests that abatacept may induce long term remission in polyarticular JIA patients, especially EO and Poly subtypes. Similar results were not observed in SoJIA patients.