title: Early Prognostic Factors Associated with the Efficacy of Infliximab Treatment for Patients with Rheumatoid Arthritis with Inadequate Response to Methotrexate.
abstract: BACKGROUND
  Early prognostic factors for the clinical response in patients with rheumatoid arthritis (RA) after 1 year of treatment with infliximab (IFX) as part of routine clinical practice were investigated.
  
  
  METHODS
  Thirty-five patients with RA with an inadequate response to methotrexate were enrolled and administered IFX (3-9 mg/kg, every 4-8 weeks). Serum trough levels of IFX and levels of 9 cytokines were measured at baseline and at 3, 6 months, and 1 year. Associations between these parameters and clinical indicators were statistically analyzed.
  
  
  RESULTS
  Serum trough levels of IFX and serum levels of interleukin (IL)-6 in the early phase of IFX treatment were investigated. Patients with low serum IL-6 achieved a higher clinical response as evaluated by the European League Against Rheumatism response criteria. Notably, the serum levels of IL-6 and IL-10 at baseline exhibited a significant positive correlation with disease activity at 1 year. Low serum levels of IL-6 and IL-10 at baseline were associated with low Disease Activity Score 28 erythrocyte sedimentation rate (DAS28-ESR). Cut-off values of IL-6 (5.45 pg/mL) and IL-10 and (1.68 pg/mL) enabled discrimination of DAS28-ESR remission from non-remission with high sensitivity and moderate specificity.
  
  
  CONCLUSIONS
  Following the initiation of IFX treatment, early disease activity and remission were associated with serum levels of IL-6. Serum levels of IL-6 and IL-10 at baseline predict the efficacy after 1 year of treatment with IFX. Patients with high serum levels of IL-6 and IL-10 at baseline before IFX treatment might require more intensive therapy to achieve higher rates of clinical remission at 1 year.
  
  
  BACKGROUND
  Eisai Co., Ltd.
authors.affiliation: Division of Rheumatology, Department of Internal Medicine, Keio University School of Medicine, Tokyo, Japan.
authors.forename: Satoko
authors.initials: S
authors.lastname: Hayashi
authors.affiliation: Division of Rheumatology, Department of Internal Medicine, Keio University School of Medicine, Tokyo, Japan.
authors.forename: Katsuya
authors.initials: K
authors.lastname: Suzuki
authors.affiliation: Division of Rheumatology, Department of Internal Medicine, Keio University School of Medicine, Tokyo, Japan.
authors.forename: Keiko
authors.initials: K
authors.lastname: Yoshimoto
authors.affiliation: Division of Rheumatology, Department of Internal Medicine, Keio University School of Medicine, Tokyo, Japan.
authors.forename: Masaru
authors.initials: M
authors.lastname: Takeshita
authors.affiliation: Division of Rheumatology, Department of Internal Medicine, Keio University School of Medicine, Tokyo, Japan.
authors.forename: Takahiko
authors.initials: T
authors.lastname: Kurasawa
authors.affiliation: Division of Rheumatology, Department of Internal Medicine, Keio University School of Medicine, Tokyo, Japan.
authors.forename: Kunihiro
authors.initials: K
authors.lastname: Yamaoka
authors.affiliation: Division of Rheumatology, Department of Internal Medicine, Keio University School of Medicine, Tokyo, Japan. tsutake@z5.keio.jp.
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Takeuchi
keywords: Clinical efficacy; Infliximab; Interleukin-6; Prognostic serum marker; Rheumatoid arthritis