Biosimilarity Assessment of 2 Filgrastim Therapeutics in Healthy Volunteers

Abstract

This study aimed to compare the pharmacokinetic, pharmacodynamic, and safety profiles of a proposed biosimilar and innovator filgrastim therapeutics in healthy volunteers. In a crossover design, 23 subjects received a single subcutaneous injection of 300‐µg filgrastim, followed by a 7‐day washout period. Assessed pharmacokinetic parameters were the maximum observed filgrastim serum concentration (Cmax), time to reach Cmax (tmax), the area under the concentration‐time curve (AUC), and elimination half‐life. Pharmacodynamics were assessed by the maximum observed absolute neutrophil count effect (Emax), tmax,E (time to reach Emax), and the area under the effect of the absolute neutrophil count –time curve. The test/reference ratio (90% confidence intervals) of Cmax of 0.992 (0.860‐1.143), AUC0–inf of 0.995 (0.891‐1.111), Emax of 0.952 (0.841, 1.078), and area under the effect of the absolute neutrophil count –time curve from time zero to 96 hours of 0.939 (0.854‐1.032), were all well within the predefined equivalence boundaries of 80% and 125%. Obtained values for tmax (∼4 hours), tmax,E (∼15 hours), and elimination half‐life (∼3.5 hours) were comparable between 2 treatment groups. The local tolerability and incidence of adverse events were comparable, with no clinically meaningful difference between biosimilar and innovator products. Altogether, the results suggested a high similarity of the proposed biosimilar to the innovator filgrastim in healthy volunteers.