Results
Real world data was obtained from 37 patients (median age: 16 years,
range 2-71) of whom 14 were <12 years of age. Observed FIX
activity levels were significantly higher than levels predicted using
the published model, with a median prediction error (PE) of -48.8%. The
novel model showed a lower median PE (3.4%) and better described
rFIX-Fc PK, especially for children <12 years of age. In the
novel model, an increase in age was correlated with a decrease in
clearance (p<0.01).