title: Antibodies to infliximab in Remicade-treated rheumatic patients show identical reactivity towards biosimilars.
abstract: The aim of this study was to determine whether antibodies to infliximab (IFX) in Remicade-treated patients cross-react with the biosimilar CT-P13.
  
  
  
  250 consecutive patients with rheumatic diseases under Remicade and 77 controls were retrospectively selected for the study. Anti-IFX antibodies at drug through levels were measured in parallel with three different bridging ELISA assays: Promonitor-ANTI-IFX kit, which uses Remicade to detect antibodies, and two more assays that use either Inflectra or Remsima with the same format. Correlation and association between each assay was studied.
  
  
  
  50.4% of patients were tested positive with Promonitor-ANTI-IFX. All were antibodies to IFX (ATI)-positive when either Inflectra or Remsima assays were used. In all comparisons positive and negative percentage agreements were 100%, and correlation coefficients were ≥0.995. No differences between rheumatoid arthritis and spondyloarthritis, or between concomitant immunosuppressives, were observed.
  
  
  
  Anti-IFX antibodies of Remicade-treated patients cross-react with either Inflectra or Remsima. Although additional epitopes may be present in the biosimilar, results suggest that epitopes influencing the immune response to IFX are also present in the biosimilar. Antibody-positive patients treated with Remicade should not be switched to the biosimilar, since antibodies will interact with the new drug and potentially lead to loss of response. This finding supports the utility for therapeutic drug monitoring before a switching strategy is considered.
authors.affiliation: R&D Department, Progenika-Grifols, Derio, Spain.
authors.forename: M Begoña
authors.initials: MB
authors.lastname: Ruiz-Argüello
authors.affiliation: R&D Department, Progenika-Grifols, Derio, Spain.
authors.forename: Ainara
authors.initials: A
authors.lastname: Maguregui
authors.affiliation: R&D Department, Progenika-Grifols, Derio, Spain.
authors.forename: Ainhoa
authors.initials: A
authors.lastname: Ruiz Del Agua
authors.affiliation: Immunology Unit, La Paz University Hospital, Madrid, Spain.
authors.forename: Dora
authors.initials: D
authors.lastname: Pascual-Salcedo
authors.affiliation: Immunology Unit, La Paz University Hospital-Idipaz, Madrid, Spain.
authors.forename: Ana
authors.initials: A
authors.lastname: Martínez-Feito
authors.affiliation: Rheumatology Department, La Paz University Hospital, Madrid, Spain.
authors.forename: Teresa
authors.initials: T
authors.lastname: Jurado
authors.affiliation: Rheumatology Department, La Paz University Hospital, Madrid, Spain.
authors.forename: Chamaida
authors.initials: C
authors.lastname: Plasencia
authors.affiliation: Rheumatology Department, La Paz University Hospital, Madrid, Spain.
authors.forename: Alejandro
authors.initials: A
authors.lastname: Balsa
authors.affiliation: Clinical Analysis, Hospital Marina Baixa, Villajoyosa, Spain.
authors.forename: Francisca
authors.initials: F
authors.lastname: Llinares-Tello
authors.affiliation: Rheumatology Department, Hospital Marina Baixa, Villajoyosa, Spain.
authors.forename: José
authors.initials: J
authors.lastname: Rosas
authors.affiliation: R&D Department, Progenika-Grifols, Derio, Spain.
authors.forename: Nerea
authors.initials: N
authors.lastname: Torres
authors.affiliation: R&D Department, Progenika-Grifols, Derio, Spain.
authors.forename: Antonio
authors.initials: A
authors.lastname: Martínez
authors.affiliation: R&D Department, Progenika-Grifols, Derio, Spain.
authors.forename: Daniel
authors.initials: D
authors.lastname: Nagore
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000911:Antibodies, Monoclonal / Q000097:blood* / Q000276:immunology; D018501:Antirheumatic Agents / Q000276:immunology*; D059451:Biosimilar Pharmaceuticals; D016022:Case-Control Studies; D003429:Cross Reactions; D004306:Dose-Response Relationship, Immunologic; D016903:Drug Monitoring; D057915:Drug Substitution; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D000069285:Infliximab / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012216:Rheumatic Diseases / Q000097:blood / Q000188:drug therapy* / Q000276:immunology; D055815:Young Adult
chemical_list: D000911:Antibodies, Monoclonal; D018501:Antirheumatic Agents; D059451:Biosimilar Pharmaceuticals; C000591237:CT-P13; D000069285:Infliximab
keywords: Anti-TNF; Rheumatoid Arthritis; Spondyloarthritis; Treatment