title: Validation and implementation of drug-dependent antibody assays in clinical trials for safety monitoring of patients dosed with roxifiban, an orally bioavailable glycoprotein IIb/IIIa antagonist.
abstract: Thrombocytopenia exposes patients to increased bleeding risk. This serious adverse event was observed with a frequency of approximately 2% in early clinical trials with the potent, orally bioavailable glycoprotein (GP) IIb/IIIa receptor antagonist roxifiban. We previously reported that drug-dependent antibodies (DDAbs) to GP IIb/IIIa are the main cause of thrombocytopenia with roxifiban. Two ELISA assays for detection of free DDAbs (in citrate plasma) and total DDAbs (in EDTA plasma to elute platelet bound DDAbs) were developed and analytically validated. These tests served two purposes during the clinical development program, to pre-screen patients for pre-existing antibodies and monitor patients for increasing antibody titers as a surrogate for eminent thrombocytopenia. The free DDAb assay showed inter and intra-assay precision of 5-12 and 12-14% CV, respectively. The total DDAb assay showed a precision of 5-10 and 4-12% CV, respectively. Three cycles of freeze-thaw did not significantly alter DDAb values in citrate plasma, EDTA plasma or extraction solution. The clinical qualifications of the two assays were conducted in two phase II clinical trials in coronary arterial disease (CAD) patients dosed with roxifiban. Both assays have demonstrated clinical sensitivity of nearly 99-100% and clinical specificity of nearly 95%.
authors.affiliation: Bristol-Myers Squibb Company, Princeton, NJ, USA. yuchen.barrett@bms.com
authors.forename: Yu Chen
authors.initials: YC
authors.lastname: Barrett
authors.forename: William
authors.initials: W
authors.lastname: Ebling
authors.forename: Henry
authors.initials: H
authors.lastname: Pieniaszek
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Billheimer
authors.forename: Dietmar
authors.initials: D
authors.lastname: Seiffert
mesh_terms: D000578:Amidines / Q000009:adverse effects* / Q000032:analysis* / Q000276:immunology; D000906:Antibodies / Q000032:analysis; D001682:Biological Availability; D002986:Clinical Trials as Topic; D004356:Drug Storage; D004797:Enzyme-Linked Immunosorbent Assay; D005615:Freezing; D006801:Humans; D007118:Immunoassay; D007202:Indicators and Reagents; D007555:Isoxazoles / Q000009:adverse effects* / Q000032:analysis* / Q000276:immunology; D019039:Platelet Glycoprotein GPIIb-IIIa Complex / Q000037:antagonists & inhibitors* / Q000276:immunology*; D011786:Quality Control; D011994:Recombinant Proteins / Q000737:chemistry; D015203:Reproducibility of Results
chemical_list: D000578:Amidines; D000906:Antibodies; D007202:Indicators and Reagents; D007555:Isoxazoles; D019039:Platelet Glycoprotein GPIIb-IIIa Complex; D011994:Recombinant Proteins; C118235:roxifiban