The half-life of rFVIIIFc is predominantly extended by FcRn expressed in somatic cells, but not in hematopoietic cells.

<p>The clearance of the following proteins is determined in bone marrow FcRn chimeric mice. (A) rFVIII (250 IU/kg), which clearance is not affected by FcRn (B) rFVIIIFc (250 IU/kg) which is predominantly protected from clearance by FcRn expressed in somatic cells (KO→WT). (C) rFIXFc (250 IU/kg) is mostly protected from clearance by FcRn expressed in somatic cells (KO→WT) (D) human IgG1 (5 mg/kg) is protected from clearance by FcRn expressed in hematopoietic cells (WT→KO). Plasma levels measured at 5 minute are set to 100% and the calculated mean residence times (MRT) are show in the graph insert, n = 4 for each data-point. Significance between plasma levels for individual time points on the PK curves is determined by an unpaired 2-tailed student t-test. A significant difference is indicated between PK curves with one or more significant time point differences (p<0.05).