title: Application of analytical detection concepts to immunogenicity testing.
abstract: The cut point and detection limit of any immunogenicity assay are two of the most important quantities that define the adequacy of an assay for detecting anti-drug antibodies against therapeutic proteins. To date in the immunogenicity testing literature, only the type I (alpha) error (i.e., the false positive) rate of the assay has been considered for establishing cut points. The "sensitivity" of an immunogenicity assay is usually reported as the concentration of a monoclonal or polyclonal anti-drug antibody standard corresponding to the signal at the cut point. We propose that a more traditional and rigorous analytical chemistry definition of the detection capability be utilized wherein both type I and type II (beta, false negative) error rates are considered. Specifically, the Hubaux-Vos technique of calculating cut points and limits of detection from predication intervals on calibration curves is recommended as a statistically rigorous approach. The utility of using receiver-operator characteristic curves for managing the type I and II error rates of an immunogenicity assay is also presented. In addition, we illustrate how a soluble receptor, sMUC18, for the therapeutic mAb ABX-MA1 can result in false positives by Biacore methodology. This result suggests that immunogenicity confirmatory experiments must be carefully designed, preferably with a smaller type I and II error rate than in the primary screening if an acceptable limit of detection can be maintained.
authors.affiliation: Amgen Fremont, Inc., 6701 Kaiser Drive, Fremont, California 94555, USA. scott.klakamp@astrazeneca.com
authors.forename: Scott L
authors.initials: SL
authors.lastname: Klakamp
authors.forename: Hong
authors.initials: H
authors.lastname: Lu
authors.forename: Mohammad
authors.initials: M
authors.lastname: Tabrizi
authors.forename: Cherryl
authors.initials: C
authors.lastname: Funelas
authors.forename: Lorin K
authors.initials: LK
authors.lastname: Roskos
authors.forename: David
authors.initials: D
authors.lastname: Coleman
mesh_terms: D000911:Antibodies, Monoclonal / Q000097:blood* / Q000276:immunology*; D061067:Antibodies, Monoclonal, Humanized; D051929:CD146 Antigen / Q000097:blood; D002138:Calibration; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods / Q000592:standards; D005188:False Negative Reactions; D005189:False Positive Reactions; D006801:Humans; D016209:Interleukin-8 / Q000037:antagonists & inhibitors; D011237:Predictive Value of Tests; D012372:ROC Curve; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D020349:Surface Plasmon Resonance / Q000379:methods* / Q000592:standards; D013997:Time Factors
chemical_list: C492798:ABX-Interleukin 8; D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D051929:CD146 Antigen; D016209:Interleukin-8; C497902:MCAM protein, human