Prediction of clinical response after 1 year of infliximab therapy in rheumatoid arthritis based on disease activity at 3 months: Posthoc analysis of the RISING study

Objective. To investigate the probability of clinical remission (REM) or low disease activity (LDA) after 1 year of infliximab (IFX) therapy based on disease activity at 3 months in patients with rheumatoid arthritis (RA). Methods. Methotrexate-refractory patients with RA received 3 mg/kg of IFX at weeks 0, 2, and 6, followed by 3 mg/kg, 6 mg/kg, or 10 mg/kg every 8 weeks from Week 14 (W14) to Week 46. Correlation of disease activity at W14 with disease activity at W54 and probability of REM/LDA at W54 were analyzed in each dosing group. Results. Disease activities at W14 were significantly correlated with both disease activity at W54 and probability of REM/LDA at W54 in patients continuing 3 mg/kg as well as in those receiving 6 mg/kg or 10 mg/kg therapy from W14. Results showed that, if approximate REM or LDA had not been achieved by W14, ≥ 50% of patients continuing 3 mg/kg therapy would not be able to achieve REMor LDAatW54. However, even in patients with high or moderate disease activity atW14, dose escalation to 6 mg/kg or 10 mg/kg enabled many to achieve REM/LDA. Conclusion. Disease activity at W14 in standard-dose IFX therapy enabled the prediction of longterm clinical response at continued standard dose, as well as subsequent escalated-dose regimens. Disease activity at W14 was hypothesized to be an important index for IFX treatment strategy.