2017 Volume 29 Issue 1 Pages 12-21
Objectives: We analyzed the clinical effectiveness of infliximab (IFX) against rheumatoid arthritis (RA) in relation to dose escalation and reduction of the dosing interval (“dose intensification” hereafter). We also investigated differences in clinical features between patients who showed a good response and those who showed a poor response.
Patients and methods: We analyzed 47 RA patients (12 males and 35 females) with an average age of 56.5 years, who had received IFX at a dose of 3.48 mg/kg, i.e. 7.3 times the average dose, prior to dose intensification. The efficacy and safety were evaluated retrospectively at 54 weeks after dose intensification.
Results: Significant improvements of disease activity score 28 - Erythrocyte Sedimentation Rate (DAS28-ESR) by introduction of IFX were maintained by the dose intensification, whereas rheumatoid factor, matrix metalloproteinase-3, and the dose of prednisolone were decreased significantly by dose intensification. IFX was discontinued in 17 patients (2 clinical remission, 5 switched to etanercept, 5 switched to tocilizumab, and 5 developed serious adverse events including pneumocystis pneumonia in 2, bacterial pneumonia in 1, infusion reaction in 1, and gastric cancer in 1). The C-reactive protein (CRP) levels and DAS28-ESR in the poor response group were significantly higher at the IFX intensification than those in the good response group. The receiver operating characteristic curve revealed that the optimum cut-off value of CRP level and DAS28-ESR to separate good response group from poor response group were 0.6 mg/dL and 3.14, respectively. The odds ratio for the risk of changing IFX due to insufficient efficacy associated with a 1.0 mg/dL increase of CRP was 1.90 (95% C.I. 1.18 - 3.08, p=0.00875).
Conclusion: Dose intensification of IFX is beneficial for management of RA patients. A higher CRP level is a risk factor for switching IFX to another bDMARD.
