Clinical Data GO KIDS evaluated the efficacy and safety of SIMPONI in 173 children (2 to 17 years of age) with pJIA and active arthritis in at least five joints that had poor response to MTX. Part 1 of the study consisted of a 16-week open-label phase, in which enrolled patients received SIMPONI 30 mg/m2 (maximum 50 mg) subcutaneously every four weeks and MTX. The 154 patients who achieved an American College of Rheumatology (ACR) Pediatric (Ped) 30 response at week 16 entered Part 2 of the study, the randomised withdrawal phase, and received SIMPONI 30 mg/m2 (maximum 50 mg) and MTX or placebo and MTX every four weeks.
The primary endpoint, the proportion of patients who achieved ACR Ped 30 response at week 16 and who did not experience a flare between week 16 and week 48, did not reach statistical significance; the majority of patients did not experience a flare between week 16 and week 48 (59 percent in the SIMPONI and MTX and 53 percent in the placebo and MTX groups, respectively; P = 0.41). However, pre-specified subgroup analyses of the primary endpoint by baseline CRP (≥1 mg/dL vs <1 mg/dL) demonstrated higher flare rates in placebo and MTX compared to SIMPONI and MTX treated patients among patients with baseline CRP ≥1 mg/dL (87 percent vs 40 percent, P = 0.0068).  In this study, the type and frequency of adverse events reported were generally similar to those seen in adult rheumatoid arthritis (RA) studies.