Comparison of biosimilar filgrastim with a reference product: pharmacokinetics, pharmacodynamics, and safety profiles in healthy volunteers

PURPOSE: Filgrastim, a granulocyte-colony stimulating factor, is used to treat patients with neutropenia, including neutropenic fever. Leucostim(®) is a recombinant filgrastim product tested for biosimilarity with its reference product, Neupogen(®). We conducted a comparative clinical trial of the 2 products. PATIENTS AND METHODS: A randomized, open-label, 2-way crossover, single-dose Phase I study was conducted for 56 healthy subjects. After a 5 and 10 μg/kg single subcutaneous administration of test and reference product, pharmacokinetic and pharmacodynamic parameters (absolute neutrophil count and CD34(+) cell count) were compared. During the study, safety tests and adverse event monitoring were performed. RESULTS: The test and the reference products had a comparable pharmacokinetic, pharmacodynamic, and safety profile. In both 5 and 10 μg/kg dosing, the 90% CIs of the test to reference ratio for primary parameters (peak plasma concentration and area under the plasma concentration vs time curve from time 0 extrapolated to the infinite time for plasma filgrastim concentration; maximal effect and area under the time-effect curve from time 0 to time of the last quantifiable effect for absolute neutrophil count) were within the 0.8–1.25 range. In addition, safety profiles between the 2 products were similar without any serious adverse events. CONCLUSION: This study has provided firm clinical evidence that the test filgrastim product is similar to its reference filgrastim product.