title: Preclinical efficacy and safety of rVIII-SingleChain (CSL627), a novel recombinant single-chain factor VIII.
abstract: BACKGROUND
  The preclinical efficacy and safety of rVIII-SingleChain (CSL627), a novel recombinant single-chain factor VIII, was assessed in a series of animal studies.
  
  
  METHODS
  In the tail-clip bleeding model, hemophilia A mice were injected with escalating doses (1-150 IU/kg) of rVIII-SingleChain, B-domain deleted (BDD) rFVIII (ReFacto AF(®)), or full-length rFVIII products (Advate(®), Helixate(®)). Total blood loss and the percentage of animals in which hemostasis occurred were assessed in this observer-blinded, randomized study. In a second non-randomized study in hemophilia A mice, thromboelastographic analysis, thrombin generation, and activated partial thromboplastin time assays were performed. General safety and toxicity were assessed in three animal species, including determination of the prothrombotic potential of rVIII-SingleChain in a rabbit venous thrombosis model.
  
  
  RESULTS
  Under acute bleeding conditions, the effect of rVIII-SingleChain on total blood loss and hemostasis was indistinguishable from BDD and full-length rFVIII. rVIII-SingleChain and full-length rFVIII (both 20 IU/kg) corrected thromboelastographic parameters, activated partial thromboplastin time, and thrombin generation to a similar degree in hemophilia A mice. In a thrombosis model, the effect of rVIII-SingleChain on thrombus incidence was non-significant and comparable to BDD rFVIII at doses up to 500 IU/kg. Treatment with rVIII-SingleChain did not cause anaphylactic reaction or local intolerance in safety and toxicity studies, and demonstrated an excellent overall safety profile.
  
  
  CONCLUSIONS
  rVIII-SingleChain showed convincing hemostatic efficacy and excellent tolerability in animal studies, warranting continued investigation in human Phase I/III trials (AFFINITY).
authors.affiliation: Preclinical Research and Development, CSL Behring GmbH, 35041 Marburg, Germany. Electronic address: Sabine.Zollner@cslbehring.com.
authors.forename: Sabine B
authors.initials: SB
authors.lastname: Zollner
authors.forename: Elmar
authors.initials: E
authors.lastname: Raquet
authors.forename: Jochen
authors.initials: J
authors.lastname: Müller-Cohrs
authors.forename: Hubert J
authors.initials: HJ
authors.lastname: Metzner
authors.forename: Thomas
authors.initials: T
authors.lastname: Weimer
authors.forename: Ingo
authors.initials: I
authors.lastname: Pragst
authors.forename: Gerhard
authors.initials: G
authors.lastname: Dickneite
authors.forename: Stefan
authors.initials: S
authors.lastname: Schulte
mesh_terms: D000818:Animals; D001779:Blood Coagulation Factors / Q000378:metabolism; D005169:Factor VIII / Q000009:adverse effects / Q000494:pharmacology*; D005260:Female; D006467:Hemophilia A / Q000097:blood / Q000188:drug therapy*; D006487:Hemostasis; D006801:Humans; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D011817:Rabbits; D011897:Random Allocation; D011994:Recombinant Proteins / Q000009:adverse effects / Q000494:pharmacology
chemical_list: D001779:Blood Coagulation Factors; D011994:Recombinant Proteins; C427184:recombinant factor VIII SQ; D005169:Factor VIII
keywords: ADA; AUC; AUC from 0 to 24hours; AUC from 0 to last timepoint; AUC(0-last); AUC(0–24h); B-domain deleted; BDD; C(max); CFT; CHO; CI; CT; Chinese hamster ovary; ELISA; ETP; FVIII; GLP; PTF; TGA; VWF; aPCC; aPTT; activated partial thromboplastin time; activated prothrombin complex concentrate; activated recombinant factor VIII; anti-drug antibody; area under the curve; clot formation time; clotting time; confidence interval; endogenous thrombin potential; enzyme-linked immunosorbent assay; factor VIII; good laboratory practice; half-life; hemostasis; maximum concentration; potentiation of thrombus formation; preclinical; rFVIII; rFVIIIa; rVIII-SingleChain; recombinant; recombinant factor VIII; t(1/2); t(max); thrombin generation assay; time taken to achieve C(max); von Willebrand factor