Soy Phosphatidylinositol Containing Nanoparticle Prolongs Hemostatic Activity of B-Domain Deleted Factor VIII in Hemophilia A Mice

Abstract

Factor VIII (FVIII) replacement therapy in Hemophilia A (HA) is complicated by a short half-life and high incidence of inhibitory antibody response against the protein. Phosphatidylinositol (PI) containing lipidic nanoparticles have previously been shown to reduce the immunogenicity and prolong the half-life of full length FVIII. It has not been established whether this prolongation in half-life improves hemostatic efficacy and whether this approach could be extended to the B-domain deleted form of FVIII (BDD FVIII). In the current study, we evaluated the pharmacokinetics (PK), hemostatic efficacy and immunogenicity of BDD FVIII associated with PI nanoparticles (PI-BDD FVIII) in HA mice. Comparative human PK was predicted using an ‘informed scaling’ approach. PI-BDD FVIII showed a ~ 1.5-fold increase in terminal half-life compared to free BDD FVIII following i.v. bolus doses of 40 IU/kg. PI-BDD FVIII treated animals retained hemostatic efficacy longer than the free FVIII treated group in a tail vein transection model of hemostasis. PI association reduced the development of inhibitory and binding antibodies against BDD FVIII after a series of i.v. injections. The combined improvements in circulating half-life and hemostatic efficacy could significantly prolong the time above clinically established therapeutic thresholds of prophylactic FVIII replacement therapy in humans.

Soy Phosphatidylinositol–Containing Lipid Nanoparticle Prolongs the Plasma Survival and Hemostatic Efficacy of B-domain–Deleted Recombinant Canine Factor VIII in Hemophilia A Dogs

“…However, we postulate that they are similar to those reported for human BDD FVIII (i.e. PI association sterically shields rcFVIII from receptor mediated clearance and proteolytic degradation 10 ). The fact that the prolongation in terminal half-life is not as pronounced as that observed with human BDD FVIII in HA mice 10 is likely due to the lower association efficiency of rcFVIII with the PI-particle.…”

“…Fluorescence spectroscopy was used to evaluate tertiary structural changes in rcFVIII as a result of association with PI nanoparticles. Association of rcFVIII with PI particles was found to be less efficient than human BDD FVIII 10 , with 39.4 ± 3.2 % of recovered protein found in association with lipid particles. A blue shift in the fluorescence emission maximum of rcFVIII was observed in the presence of PI particles (Fig.…”

“…PI containing lipid nanoparticles can decrease the immunogenicity and prolong the plasma survival and hemostatic efficacy of human BDD FVIII in HA mice. Allometric predictions of comparative human PK suggest lipidic FVIII could be dosed once weekly for prophylactic purposes compared to thrice weekly with free FVIII, which would be a significant improvement in HA clinical management 10 . The objective of this work was to evaluate whether the lipid-mediated improvements in BDD FVIII PK and PD observed in HA mice translate to higher preclinical species.…”

“…These lipid nanoparticles extend the circulating half-life and hemostatic efficacy of BDD FVIII as well as mitigate immune responses against the protein, in a mouse model of HA. Lipidic BDD FVIII is more potent than the free form of the protein in HA mice 10 . The combined improvements in PK and PD have been predicted to substantially prolong the time above clinically established therapeutic thresholds, permitting once weekly prophylactic dosing of BDD FVIII.…”

“…A phosphatidylinositol (PI) containing lipidic nanoparticle for the delivery of B-domain deleted FVIII (BDD FVIII) has been developed 10 . These lipid nanoparticles extend the circulating half-life and hemostatic efficacy of BDD FVIII as well as mitigate immune responses against the protein, in a mouse model of HA.…”