title: Abatacept: the evidence for its place in the treatment of rheumatoid arthritis.
abstract: BACKGROUND
  Rheumatoid arthritis (RA) is the most common inflammatory joint disease in adults with a prevalence of 0.5-1%. The development of targeted therapies, especially anti-TNF (tumor necrosis factor) treatment, has improved disease outcome during the last decade. But despite this progress 25-30% of patients still show unsatisfactory response. Abatacept is a costimulation blocker that inhibits T-cell activation and interrupts the process that leads to inflammation in RA.
  
  
  OBJECTIVE
  The purpose of this article is to review the clinical trials of abatacept and to discuss how it will fit into the treatment of RA. The medical literature was reviewed for appropriate articles and 123 articles have been identified containing the search terms "abatacept OR CTLA4-Ig AND rheumatoid." All clinical trials were reviewed with respect to clinical and radiologic outcome, quality of life, and safety of patients with RA receiving abatacept therapy.
  
  
  METHODS
  There are seven (phase II or phase III) clinical trials that have clearly demonstrated efficacy and safety of this new drug. Furthermore, radiographic data show that abatacept also inhibits the progression of joint destruction, one of the important burdens of RA. Abatacept can be used concomitantly with conventional disease-modifying antirheumatic drugs or as monotherapy. Due to an increased risk of infections and malignancies but without an important enhancement of efficacy, simultaneous treatment with abatacept and other biologic response modifiers is not recommended.
  
  
  CONCLUSIONS
  With its different mechanism of action, abatacept may be an alternative therapy for patients with an inadequate response to other arthritis therapies, especially for those patients with RA refractory to anti-TNF treatment. Cost effectiveness is dependent on underlying disease progression.
authors.affiliation: Medical University of Vienna, Vienna, Austria.
authors.forename: Marcus D
authors.initials: MD
authors.lastname: Köller