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®

Study rationale: Bio-ker has developed the new formulation of filgrastim BK0023 with the same active content as Neupogen®. BK0023 is expected to have the same tolerability profile and clinical effects as Neupogen® in controlling myelo-toxicity induced by chemotherapy given for the treatment of solid and haematological tumours. It is worth noting that the production and manufacturing procedures allow to have a reduction of drug cost thus it is likely to have pharmacoeconomic advantages.

The study is aimed at investigating the pharmacodynamic equivalence and the pharmacokinetic bioequivalence of the new BK0023 injectable formulation of filgrastim 0.3 mg/mL by Bio-Ker S.r.l. vs. the comparator (Neupogen® 0.3 mg/mL, Dompé Biotec S.p.A., Italy). Healthy male subjects will receive test and reference at the doses of 2.5 and 5 µg/kg/day for 7 consecutive days and at the dose of 10 µg/kg/day for 5 consecutive days according to a randomised cross-over design. Pharmacodynamics, pharmacokinetics and safety of BK0023 injectable formulation 0.3 mg/mL and of Neupogen® 0.3 mg/mL, administered in 2 consecutive periods with a wash-out of at least 28 days elapsing between the last injection of period I and the first of period II, are compared.

Study design: Single and multiple escalating dose, double-blind, randomised, two-way cross-over, pharmacodynamic and pharmacokinetic bioequivalence study.

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.

Eligibility Criteria:
Inclusion Criteria:

* a body mass index (BMI) between 18 and 28 kg/m2,
* a body weight between 60 and 90 kg,
* good health based on medical history, physical examination, a 12-lead electrocardiogram (ECG) and routine haematology and blood chemistry tests,
* willingness to provide written informed consent
* values of leukocytes and thrombocytes had to be inside the normality range at the screening.

Exclusion Criteria:

* intake of any concomitant medication,
* a history of drug, caffeine (\>5 cups coffee/tea/day) or tobacco (\>/=10 cigarettes/day) abuse, or alcohol consumption in excess of two drinks per day, as defined by the U.S.D.A. dietary guidelines,
* ascertained or presumptive hypersensitivity to the active compound or history of anaphylaxis to drugs.