Background Introduction of infliximab and adalimumab has been a major advance in the treatment of rheumatoid arthritis (RA), but some patients initially responding to infliximab 3 mg/kg/8th week are unable to sustain clinical response.
Objectives To establish whether RA patients with an unsustainable clinical response to infliximab 3 mg/kg/8th week achieves long-term treatment response by dose escalation to infliximab 3 mg/kg/6th-4th week, or by switching to adalimumab 40 mg s.c. eow.
Methods We included 13 RA patients from Denmark and Sweden with at least 6 month prior treatment with infliximab 3mg/kg/8th, who after an initial clinical response showed moderate to severe disease activity (DAS28 >3.2) and a fading response to infliximab.
Fading response was defined as: 1) remission (DAS28 <2.6) while on infliximab, and increased disease activity (DAS28 >3.2); and/or 2) an increase in DAS28 score of 1.2 or more; and/or 3) an increase in HAQ score of 0.5 or more.
Patients were randomized to either adalimumab (group 1) or infliximab (group 2A) treatment. Infliximab treated patients who had insufficient response at week 12, could be increased in dose interval to every 4th week (group 2B).
Results Baseline characteristics (median (range)) for all included patients were: male/female: 3/10, age: 57 (26-78) years, duration of RA: 6 (2-40) years, time treated with infliximab before inclusion: 11 (6-72) month, time since last infusion with infliximab: 52 (40-85) days, patients in randomization group (adalimumab/infliximab): 6/7, 28-TJC: 11 (3-18), 28-SJC: 5 (1-17), HAQ-score: 1.25 (1.0-1.63), and CRP: 17 (4-88) mg/L.
Three patients discontinued the trial prematurely (two adalimumab treated patients due to severe pneumonia and lack of efficacy, respectively, and one infliximab treated patient due to lack of efficacy), and they all had a moderate EULAR response at the discontinuation visit. Of 10 patients completing all visits a good EULAR response was achieved by 3 (group 1: 1 patient, group 2A: 2 patients), and good or moderate EULAR response was achieved by 7 patients (group 1: 3 out of 4 patients, group 2A: 3 out of 4 patients, group 2B: 1 out of 2 patients).
Table 1 shows DAS28 and ACR response.
Median (range) and percentages are shown. Changes did not reach statistical significant levels.
Conclusions In a randomized study of patients with fading clinical response to infliximab 3mg/kg/8th week moderate or good EULAR response was obtained in the majority (70-80%) of patients by increasing the dose of infliximab or switching to adalimumab.
Disclosure of Interest None Declared