title: Characterization and Application of a Unique Panel of Monoclonal Antibodies Generated against Etanercept.
abstract: The clinical response in ankylosing spondylitis (AS) patients treated with biologic agents can be influenced by pharmacokinetic variability among and within these patients. Therapeutic drug monitoring is seen as a valuable tool to improve patient care. The aim of this study was to generate a panel of mAbs toward etanercept (ETN) and to determine ETN and anti-ETN concentrations in AS patients. mAbs against ETN (MA-ETN) were generated using hybridoma technology. For quantification of ETN concentrations, a mAb-based TNF-coated ELISA and a mAb/mAb-based sandwich-type ELISA were developed. For evaluation of the anti-ETN Ab response, a bridging ELISA, as well as a functional cell-based assay, were constructed. Disease activity of the AS patients was measured with the AS Disease Activity Score (ASDAS). Active disease was defined as ASDAS ≥ 2.1. A total of 59 of 76 generated mAbs were ETN specific and were characterized further. Fifty-one mAbs revealed inhibitory properties in a cell-based assay. Analysis of serum concentrations of 21 ETN-treated AS patients with the TNF/MA-ETN68C5-HRP ELISA and the MA-ETN63C8/MA-ETN61C1-HRP ELISA revealed a good Pearson's r (+0.974) but a poor intraclass correlation coefficient (+0.528) as the result of underestimation of the values in the former ELISA. At 24 wk, ETN concentrations were similar in patients with ASDAS < 2.1 and ≥ 2.1. Anti-ETN Abs were not detected in any of the patient samples tested. In conclusion, highly sensitive mAb-based immunoassays were developed for quantification of ETN and anti-ETN concentrations. The impact of these methods needs to be evaluated further in clinical practice.
authors: Department of Pharmaceutical and Pharmacological Sciences, Laboratory for Therapeutic and Diagnostic Antibodies, KU Leuven, B-3000 Leuven, Belgium;
authors: Iris
authors: I
authors: Detrez
authors: Department of Pharmaceutical and Pharmacological Sciences, Laboratory for Therapeutic and Diagnostic Antibodies, KU Leuven, B-3000 Leuven, Belgium;
authors: Els
authors: E
authors: Brouwers
authors: Department of Pharmaceutical and Pharmacological Sciences, Laboratory for Therapeutic and Diagnostic Antibodies, KU Leuven, B-3000 Leuven, Belgium;
authors: Miet
authors: M
authors: Peeters
authors: PharmAbs, The KU Leuven Antibody Center, B-3000 Leuven, Belgium; and.
authors: Nick
authors: N
authors: Geukens
authors: Department of Rheumatology, University Hospitals Leuven, B-3000 Leuven, Belgium.
authors: Kurt
authors: K
authors: de Vlam
authors: Department of Pharmaceutical and Pharmacological Sciences, Laboratory for Therapeutic and Diagnostic Antibodies, KU Leuven, B-3000 Leuven, Belgium; ann.gils@pharm.kuleuven.be.
authors: Ann
authors: A
authors: Gils
mesh_terms: D019138:Antibodies, Blocking / Q000378:metabolism*; D000911:Antibodies, Monoclonal / Q000378:metabolism*; D004797:Enzyme-Linked Immunosorbent Assay; D000068800:Etanercept / Q000276:immunology / Q000378:metabolism / Q000627:therapeutic use*; D006801:Humans; D006825:Hybridomas; D008991:Monitoring, Physiologic / Q000379:methods; D015588:Observer Variation; D012720:Severity of Illness Index; D013167:Spondylitis, Ankylosing / Q000276:immunology / Q000628:therapy*; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
chemical_list: D019138:Antibodies, Blocking; D000911:Antibodies, Monoclonal; D014409:Tumor Necrosis Factor-alpha; D000068800:Etanercept