Comparative immunogenicity of recombinant B domain-deleted porcine factor VIII and Hyate:C in hemophilia A mice presensitized to human factor VIII.
Hyate is a commercial plasma-derived porcine factor (F)VIII concentrate that is used in the treatment of patients with inhibitory antibodies to FVIII. OBI-1 is a recombinant B domain-deleted form of porcine FVIII that is in clinical development for the same indication. Hemophilia A mice were presensitized with human FVIII to simulate clinical inhibitory antibody formation and then were randomized to receive OBI-1 or Hyate:C in a comparative immunogenicity trial. OBI-1 or Hyate:C were given in a series of four intravenous injections at weekly intervals at doses of 1, 10, or 100 U kg(-1). Inhibitory antibodies to porcine FVIII were not detected by Bethesda assay in most of the mice given OBI-1 or Hyate:C at doses of 1 or 10 U kg(-1), but were identified in 81% and 94% of mice given 100 U kg(-1) of OBI-1 or Hyate:C, respectively. There was no significant difference between OBI-1 and Hyate:C in inhibitory antibody formation at any dose, although there was a trend toward a lower Bethesda titer in OBI-1-treated mice at 10 U kg(-1) (P = 0.09). Total anti-FVIII antibodies to Hyate:C and OBI-1 were also measured by ELISA using immobilized purified plasma-derived porcine FVIII and OBI-1, respectively, as antigens. At the 10 and 100 U kg(-1) doses, the mean anti-FVIII response was higher in Hyate:C-treated-mice than in OBI-1-treated mice (P = 0.02 and P = 0.004, respectively). The results using this model suggest that OBI-1 may be less immunogenic and safer than Hyate:C in FVIII inhibitor patients.
Parker
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Winship Cancer Institute, Emory University, Atlanta, GA 30322, USA.
Craddock
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Barrow
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Lollar
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D000818:Animals; D000910:Antibodies, Heterophile / Q000097:blood; D000917:Antibody Formation / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D004797:Enzyme-Linked Immunosorbent Assay; D005169:Factor VIII / Q000276:immunology* / Q000627:therapeutic use; D006467:Hemophilia A / Q000188:drug therapy* / Q000276:immunology; D006801:Humans; D051379:Mice; D018345:Mice, Knockout; D010446:Peptide Fragments / Q000276:immunology* / Q000627:therapeutic use; D013552:Swine
D000910:Antibodies, Heterophile; C451034:B-domain-deleted factor VIII; D010446:Peptide Fragments; D005169:Factor VIII