Vol.19 No.5

Original Article

Impact of trough serum level on radiographic and clinical response to infliximab plus methotrexate in patients with rheumatoid arthritis: results from the RISING study

Authors

Tsutomu Takeuchi1 , Nobuyuki Miyasaka2 , Kazuhiko Inoue3 , Tohru Abe4 , Takao Koike5

  • Division of Rheumatology and Clinical Immunology, Saitama Medical Center, Saitama Medical University, 1981 Kamoda, Kawagoe Saitama, 350-8550, Japan
  • Department of Medicine and Rheumatology, Graduate School of Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8510, Japan
  • Department of Orthopaedic Surgery, Tokyo Women’s Medical University, Medical Center East, 2-1-10 Nishigou Arakawa-ku, Tokyo 116-8567, Japan
  • Saitama Medical Center, Saitama Medical University, 1981 Kamoda, Kawagoe Saitama, 350-8550, Japan
  • Department of Medicine II, Graduate School of Medicine, Hokkaido University, N15W7 Kita-ku, Sapporo 060-8638, Japan
Received:

15 April 2009

Accepted:

8 June 2009

Published online:

22 July 2009

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Abstract

This study is a prospective, randomized, double-blind study to compare the efficacy and safety of 10 mg/kg infliximab with those of 3 mg/kg infliximab treatment in methotrexate-refractory rheumatoid arthritis patients. After the patients received 3 mg/kg infliximab infusion at weeks 0, 2, and 6, they were randomly assigned to be administered 3, 6 or 10 mg/kg infliximab every 8 weeks from week 14 to 46. Mean American College of Rheumatology improvement (ACR-N) at week 54, the primary endpoint, was 51.3% and 58.3% for the 3 mg/kg and 10 mg/kg groups, respectively, with a statistically significant difference. Treatment with 10 mg/kg was found to be remarkably beneficial in patients who had not responded to three infusions with 3 mg/kg at week 10. The median changes in the modified Sharp score were 0.0 in the two groups. There were no significant differences in the incidences of adverse events between the groups. In patients who achieved better clinical response or greater inhibition of progression of joint damage, trough serum infliximab level was significantly higher than in patients who did not. The magnitudes of both efficacies were correlated with the trough serum infliximab level (ClinicalTrials.gov number: NCT00691028).

Key words

Clinical trial - Infliximab - Rheumatoid arthritis - Serum level - Tumor necrosis factor (TNF) antagonist