title: Evaluation of potential antigenicity of active-site-inhibited recombinant human FVIIa (FFR-rFVIIa) in an immune-tolerant rat model.
abstract: Recombinant human FVIIa (rFVIIa) was inactivated by coupling Phe-Phe-Arg-CK- (FFR) covalently to the active site of the enzyme. To test the chemically-modified human protein for potential antigenicity prior to clinical trial an immune-tolerant rat model was established. Intraperitoneal injection of the parent compound, human rFVIIa, within 30 h after birth, followed by repeated subcutaneous challenge with rFVIIa in Freunds incomplete adjuvant resulted in 79% non-responding rats at day 32. Monthly subcutaneous challenge showed that the induced tolerance was stable over the 3 months study period in 80% of the rats. The clinically relevant route, intravenous administration, was used for evaluating the potential antigenicity of FFR-rFVIIa. Repeated intravenous administration of different dosages of FFR-rFVIIa did not break tolerance, indicating that FFR-rFVIIa might not be antigenic, for a limited number of intravenous administrations in a clinical setting.
authors.affiliation: NovoSeven Research, Novo Nordisk A/S, Måløv, Denmark. emn@novonordisk.com
authors.forename: Else Marie
authors.initials: EM
authors.lastname: Nicolaisen
authors.forename: Hanne
authors.initials: H
authors.lastname: Kristensen
authors.forename: Annemarie
authors.initials: A
authors.lastname: Kristensen
authors.forename: Ulla
authors.initials: U
authors.lastname: Hedner
mesh_terms: D000590:Amino Acid Chloromethyl Ketones / Q000494:pharmacology*; D000818:Animals; D000831:Animals, Newborn; D000910:Antibodies, Heterophile / Q000096:biosynthesis / Q000276:immunology; D015478:Antigens, Heterophile / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D001665:Binding Sites / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D004797:Enzyme-Linked Immunosorbent Assay; D015942:Factor VIIa / Q000008:administration & dosage / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D005260:Female; D006801:Humans; D007108:Immune Tolerance; D007114:Immunization; D007117:Immunization, Secondary; D007274:Injections, Intraperitoneal; D007275:Injections, Intravenous; D008297:Male; D023421:Models, Animal; D051381:Rats; D017208:Rats, Wistar; D011993:Recombinant Fusion Proteins / Q000008:administration & dosage / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000276:immunology; D013045:Species Specificity; D013047:Specific Pathogen-Free Organisms
chemical_list: D000590:Amino Acid Chloromethyl Ketones; D000910:Antibodies, Heterophile; D015478:Antigens, Heterophile; D004791:Enzyme Inhibitors; D011993:Recombinant Fusion Proteins; C027587:phenylalanyl-phenylalanyl-arginine chloromethyl ketone; D015942:Factor VIIa