Evaluation of Dose-response, Pharmacodynamic and Pharmacokinetic Bioequivalence of Filgrastim in Healthy Male Volunteers After Single and Multiple-dose Subcutaneous Administration of the Test Injectable Formulation BK0023 vs. Neupogen®

In a first part of the study, 16 healthy male subjects will be included in each dose group and will receive test and reference product according to the cross-over design. After the end of the second period of each dose group (completion of both cross-over periods for each dose group) the pharmacodynamic and pharmacokinetic primary parameters will be calculated. The blinding will be temporarily broken by one statistician for the ad interim analysis of primary parameters that will be performed after conclusion of the treatment of 16 subjects for each dose group (results are not disclosed) with the aim to re-calculate the sample size and to conclude the study with the necessary and sufficient number of subjects for each dose regimen. The study design was chosen according to the internationally recognised guideline for pharmacokinetics studies and in accordance with the EMEA guidance on similar medicinal products containing recombinant granulocyte-colony stimulating factor (G-CSF), which is annexed to the guideline on similar biological medicinal products containing biotechnology-derived proteins as active substance: non-clinical and clinical issues. A clinical development plan including the study outline was also submitted to EMEA, which examined the documentation and gave advice about the present study design . A multiple-dose design was chosen instead of a single-dose design, since G-CSF pharmacokinetics is non linear due to 2 reasons: non-proportional increase with dose and time dependent non-linearity. However, pharmacodynamic equivalence and pharmacokinetic bioequivalence will be both tested after the 1st and the last dose of the multiple dose treatment. Since the effects of r-h-met-G-CSF can be directly measured as pharmacodynamic responses, i.e. the increase in the absolute neutrophil count (ANC) and the development of peripheral blood cells (CD34+ cells), both parameters will be evaluated for the equivalence testing. Dose levels of 2.5 and 5 μg/kg/day were chosen for the pharmacodynamic equivalence, since literature data show a clear dose-response relationship in terms of the pharmacodynamic parameters over this range. The 10 μg/kg/day dose was chosen to make the investigated range relevant with respect to the clinical indications and the usual praxis for Neupogen®. Moreover, the subcutaneous administration was chosen, since this administration route is the most commonly used in the clinical setting.