title: How good is to switch between biologics? A systematic review of the literature.
abstract: Despite the biological rationale for switching between TNF-antagonists, there is not a definitive answer from a clinical point of view.
  
  
  METHODS
  We performed a systematic review. The strategy for the literature search included synonyms for the active drugs, trade names, and different synonyms for biologic therapies, plus the words "switch" or "switching", limited to studies in humans. The time limit was March 1st 2007. From 256 initial hits in Medline and Embase, plus 13 abstracts from rheumatology meetings, we finally included 33 studies.
  
  
  CONCLUSIONS
  The most frequently died switches are those between etanercept and infliximab. The mean number of patients studied per type of switch was 126. There are, apart from retrospective observational studies and cases series, 5 prospective cohorts from biologic registries, 1 randomised open-label clinical trial and 1 phase IV clinical trial, all seven of which are of moderate to good quality. There results are promising but not excellent. Any switch, especially those between monoclonal antibodies, have an effect size that is usually lower than that of a first biologic. When the switch is due to an adverse event with the first TNF-antagonist, however, the response rate of the second one is high. Perhaps the best alternative when a first TNF-antagonist fails is to start a different type of biologic, and leave the switch to another TNF-antagonist in the case of adverse event to the previous one.
authors.affiliation: Unidad de Investigación, Fundación Espanola de Reumatología, Madrid, Spain. lcarmona@ser.es
authors.forename: Loreto
authors.initials: L
authors.lastname: Carmona
authors.forename: Ana
authors.initials: A
authors.lastname: Ortiz
authors.forename: Miguel Angel
authors.initials: MA
authors.lastname: Abad
mesh_terms: D001172:Arthritis, Rheumatoid / Q000188:drug therapy; D001688:Biological Products / Q000627:therapeutic use*; D006801:Humans; D000079424:Tumor Necrosis Factor Inhibitors
chemical_list: D001688:Biological Products; D000079424:Tumor Necrosis Factor Inhibitors