To evaluate the effect of infliximab dose escalation in incomplete responders in a randomised controlled trial.
141 rheumatoid arthritis (RA) patients treated with infliximab for 12 months (3 mg/kg; intervals 0, 2, 6 and then 8 weeks) who responded to the drug (disease activity score in 28 joints (DAS28) decrease >1.2) but who were not in remission (DAS28 >2.6) were enrolled into the study. Patients were randomly assigned into arm A, 3 mg/kg, and arm B, 5 mg/kg infliximab every 8 weeks. Outcome measures included the DAS28, its components and C-reactive protein (CRP).
There were no significant differences in changes in the DAS28, its components, or CRP in patients in arms A and B during the 12 months of treatment. All patients showed a DAS28 decrease greater than 0.6 after 28 weeks. Eleven patients interrupted therapy in arm A and 14 in arm B. Infusion reactions and non-serious adverse events were observed in 4.2% and 28.2% of arm A patients and in 7.2% and 47.8% of arm B patients. The frequency of serious adverse events was comparable between arms A and B (16.9% and 15.9%, respectively), and the frequency of serious infections was not significantly greater in the higher dose group (5.8%) than in the lower dose group (5.6%).
In this setting, increasing the infliximab dose from 3 mg/kg to 5 mg/kg in RA patients with residual disease activity did not improve efficacy but moderately increased toxicity. These data indicate that a switch to another biological treatment would be a more appropriate strategy in incomplete responders.