Background: Three comparative clinical studies assessed the pharmacokinetics (PK), pharmacodynamics (PD), immunogenicity and safety of PF-06881893 (filgrastim-aafi; Nivestym™), a filgrastim biosimilar, versus US-licensed reference product (filgrastim; US-Neupogen®) in healthy volunteers (HVs).
Methods: Two separate open-label, crossover-design PK/PD studies were conducted: a single-dose study (n = 24) and a multiple-dose study (n = 60). In each study, HVs were randomized to Nivestym followed by US-Neupogen, or vice versa. Study drug (5 μg/kg) was administered subcutaneously as a single injection or as five consecutive daily injections. Primary PK and PD endpoints were area under the filgrastim serum concentration-time curve, maximum observed concentration, area under the effect curve (AUEC) for absolute neutrophil count (ANC), maximum observed ANC, AUEC for cluster of differentiation (CD)-34+ count, and maximum observed CD34+ count. In an open-label, parallel-design, non-inferiority, comparative immunogenicity study, HVs were randomized (n = 128/treatment) to Nivestym or US-Neupogen. The primary endpoint was the proportion of subjects with a negative baseline antidrug antibody (ADA) test result and one or more confirmed post-dose positive ADA result.
Results: Overall demographics were as follows: female (n = 162/340); White (n = 274/340), Black (n = 58/340), and other (n = 8/340); age (18-65 years); and weight (50.8-96.5 kg). All primary PK and PD endpoints met the pre-specified criteria for PK and PD equivalence. The primary endpoint in the comparative immunogenicity study met pre-specified criteria for non-inferiority.
Conclusions: Nivestym demonstrated PK and PD equivalence in single and multiple subcutaneous-dose settings and non-inferiority for immunogenicity to US-Neupogen, with a comparable safety profile, supporting the demonstration of biosimilarity.