Population pharmacokinetic and pharmacodynamic model-based comparability assessment of a recombinant human Epoetin Alfa and the Biosimilar HX575

J Clin Pharmacol. 2012 Nov;52(11):1624-44. doi: 10.1177/0091270011421911. Epub 2011 Dec 12.


The aim of this study was to develop an integrated pharmacokinetic and pharmacodynamic (PK/PD) model and assess the comparability between epoetin alfa HEXAL/Binocrit (HX575) and a comparator epoetin alfa by a model-based approach. PK/PD data-including serum drug concentrations, reticulocyte counts, red blood cells, and hemoglobin levels-were obtained from 2 clinical studies. In sum, 149 healthy men received multiple intravenous or subcutaneous doses of HX575 (100 IU/kg) and the comparator 3 times a week for 4 weeks. A population model based on pharmacodynamics-mediated drug disposition and cell maturation processes was used to characterize the PK/PD data for the 2 drugs. Simulations showed that due to target amount changes, total clearance may increase up to 2.4-fold as compared with the baseline. Further simulations suggested that once-weekly and thrice-weekly subcutaneous dosing regimens would result in similar efficacy. The findings from the model-based analysis were consistent with previous results using the standard noncompartmental approach demonstrating PK/PD comparability between HX575 and comparator. However, due to complexity of the PK/PD model, control of random effects was not straightforward. Whereas population PK/PD model-based analyses are suited for studying complex biological systems, such models have their limitations (statistical), and their comparability results should be interpreted carefully.

Publication types

  • Comparative Study
  • Randomized Controlled Trial
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Administration, Intravenous
  • Area Under Curve
  • Epoetin Alfa
  • Erythrocyte Count
  • Erythropoietin / administration & dosage
  • Erythropoietin / blood
  • Erythropoietin / pharmacokinetics*
  • Hematinics / administration & dosage
  • Hematinics / blood
  • Hematinics / pharmacokinetics*
  • Hemoglobins / analysis
  • Humans
  • Injections, Subcutaneous
  • Male
  • Models, Biological*
  • Monte Carlo Method
  • Recombinant Proteins / administration & dosage
  • Recombinant Proteins / blood
  • Recombinant Proteins / pharmacokinetics
  • Therapeutic Equivalency


  • Hematinics
  • Hemoglobins
  • Recombinant Proteins
  • Erythropoietin
  • Epoetin Alfa