Background: We evaluated the effect of infliximab on markers of inflammation in patients with juvenile idiopathic arthritis (JIA).
Methods: In this randomized, placebo-controlled substudy, 122 patients with JIA received infliximab 3 mg/kg + methotrexate (MTX)(n = 60) or placebo + MTX (n = 62) at weeks 0, 2, and 6. At week 14, patients receiving placebo + MTX crossed over to infliximab 6 mg/kg + MTX; patients receiving infliximab 3 mg/kg + MTX continued treatment through week 44. Sera and plasma from eligible patients receiving infliximab 3 mg/kg + MTX (n = 34) and receiving placebo→infliximab 6 mg/kg +MTX (n = 38) were collected at weeks 0, 2, 14, 16, 28, and 52 and analyzed for inflammatory markers (IL-6, IL-12p40, ICAM-1, MMP-3, VEGF, TNF-α, and CRP).
Results: At week 2, decreases from baseline in IL-6, ICAM-1, MMP-3, TNF-α, and CRP were greater with infliximab versus placebo treatment, and with the exception of CRP, these differences were generally maintained through week 14. The decreases from baseline to week 52 in IL-6, ICAM-1, VEGF, MMP-3, and CRP and increases in IL-12p40 levels were larger in patients receiving placebo→infliximab 6 mg/kg +MTX versus infliximab 3 mg/kg + MTX treatment. Patients receiving infliximab 3 mg/kg+MTX who achieved an American College of Rheumatology Pediatric 30 (ACR-Pedi-30) response had significantly larger decreases from baseline in ICAM-1 (p = 0.0105) and MMP-3 (p = 0.0253) at week 2 and in ICAM-1 (p = 0.0304), MMP-3 (p = 0.0091), and CRP (p = 0.0011) at week 14 versus ACR-Pedi-30 nonresponders.
Conclusion: Infliximab + MTX attenuated several inflammatory markers in patients with JIA; larger decreases in ICAM-1, MMP-3, and CRP levels were observed in ACR-Pedi-30 responders versus nonresponders.
Trial registration: NCT00036374.