A Prospective, Multi-Center, Randomized Clinical Trial to Compare the Pharmacokinetic Properties of Human-Cl rhFVIII, a New Human-Cell Line Derived Recombinant Factor VIII, with Those of a Full-Length Recombinant Factor VIII Expressed in Baby Hamster Kidney Cells,

human-cl rhFVIII is the first recombinant factor VIII (FVIII) concentrate expressed in a human cell line (Human Embryonic Kidney (HEK) 293F cells). The manufacturing process includes two steps for virus inactivation and removal (solvent/detergent treatment and a nanofiltration). No animal- or human-derived materials are added to the culture medium or during the purification and final formulation.

The primary objective of this study is to compare the pharmacokinetics (PKs) of human-cl rhFVIII, a B-domain deleted rFVIII product expressed in a human cell line, with a commercially available full-length rFVIII product (Kogenate FS), which is expressed in Baby Hamster Kidney (BHK) cells.

This study is an open, multinational, prospective, multicenter clinical phase-II trial. The PK properties of human-cl rhFVIII and Kogenate FS were determined using a randomized two-period, cross-over design. After a 96 hours or more wash-out phase of any previously administered FVIII product, subjects received a single intravenous dose of 50 IU/kg body weight of one of the products. Blood samples were collected over a 48-h period and FVIII coagulant activity (FVIII:C) was measured by validated chromogenic substrate and one-stage clotting assay in a central laboratory, which also assigned drug potency with the same assays. Following completion of the PK segment of the study, subjects will be followed for at least 50 Exposure Days and at least 6 months of treatment with human-cl rhFVIII to evaluate the efficacy and safety of on-demand treatment. The planned interim analysis stipulates the comparison of the complete PK profile of human-cl rhFVIII and Kogenate FS with the bioequivalence of the AUC as the primary endpoint. The full efficacy and safety profile will be reported when the study is completed.

Twenty-two adolescent and adult PTPs with severe hemophilia A (FVIII:C <1%) were enrolled at 10 study centers in the United States and Europe. The key PK parameters (AUC, elimination half-life, in-vivo recovery, clearance) are comparable between human-cl rhFVIII and Kogenate FS both for the one-stage and chromogenic assays. The two products were judged to be bioequivalent as the 90% confidence interval of the ratio of the geometric mean values of the AUC fell within 80–125%. human-cl rhFVIII has been well tolerated and no safety or efficacy issues have been reported so far, in particular no inhibitors or non inhibitory antibodies were detected or reported.

The PK data from this study indicate that human-cl rh FVIII is bioequivalent to a licensed rFVIII concentrate measured by the one stage and the chromogenic assays. In this study as well as in the other ongoing clinical studies, which examine the efficacy and safety of human-cl rhFVIII during prophylactic treatment in children and adults with severe hemophilia A, the product has been safe and well tolerated so far.

Knaub:Octapharma AG: Employment. Valentino:Baxter Bioscience: Consultancy; GTC Biotherapeutics: Consultancy; Bayer Healthcare: Consultancy; NovoNordisk: Consultancy; Inspiration Bioscience: Consultancy; Biogen: Consultancy. Manco-Johnson:Octapharma AG: Consultancy.