Repeated oral administration of chitosan/DNA nanoparticles delivers functional FVIII with the absence of antibodies in hemophilia A mice

BACKGROUND: Current treatment of hemophilia A is expensive and involves regular infusions of factor (F)VIII concentrates. The supply of functional FVIII is further compromised by the generation of neutralizing antibodies. Thus, the development of an alternative safe, cost effective, non-invasive treatment that circumvents immune response induction is desirable. OBJECTIVES: To evaluate the feasibility of oral administration of chitosan nanoparticles containing FVIII DNA to provide sustainable FVIII activity in hemophilia A mice. METHODS: Nanoparticles were characterized for morphology, DNA protection and transfection efficiency. Oral administration of nanoparticles containing canine FVIII in C57Bl/6 FVIII(-/-) hemophilia A mice was evaluated for biodistribution, plasma FVIII activity and phenotypic correction. Sustainable FVIII expression was elucidated after repeated nanoparticle administration. Immune responses to repeated oral nanoparticle administration were also investigated. RESULTS: Chitosan nanoparticles had a particle size range of 200-400 nm and protected DNA from endonuclease and pH degradation. In addition, nanoparticles transfected HEK 293 cells resulted in expression of eGFP, luciferase and FVIII. Hemophilia A mice that ingested chitosan nanoparticles demonstrated transient canine FVIII expression reaching > 100 mU 1 day after treatment, together with partial phenotypic correction. The delivered FVIII plasmid DNA was detected in the intestine and, to a lesser extent, in the liver. Importantly, repeated weekly administrations restored FVIII activity. Furthermore, inhibitors and non-neutralizing FVIII antibodies were not detectable. CONCLUSIONS: Repeat oral administration of FVIII DNA formulated in chitosan nanoparticles resulted in sustained FVIII activity in hemophilic mice, and thus may provide a non-invasive alternative treatment for hemophilia A.