GlycoPEGylated Filgrastim XM22 Fixed Dose Demonstrates Similar Activity in Comparison to Pegfilgrastim in Healthy Volunteers after Single Administration.

XM22 is a glycoPEGylated recombinant human G-CSF that interacts with the G-CSF receptor by binding and activation. In pilot studies in non-neutropenic animals, XM22 demonstrated a similar PK/PD profile compared to pegfilgrastim. By its longer duration of action compared to filgrastim a once per cycle dosing as fixed dose in chemotherapy treated cancer patients for the reduction of duration of severe neutropenia and incidence of febrile neutropenia is intended.

METHODS: A single center, randomized, single-blind study of XM22, administered as single fixed dose given by the s.c. route, was conducted to assess safety, pharmacokinetic profile and pharmacodynamic properties based on absolute neutrophil count (ANC) and CD34+ cell count. Male or female healthy volunteers were assigned to either XM22 6 mg or pegfilgrastim 6 mg fixed dose treatment.

RESULTS: 36 healthy volunteers were enrolled in two treatment groups and completed 21 day follow-up. Injections were generally well-tolerated with no discontinuations due to adverse events or serious adverse events. Pharmacodynamic data were compared between the fixed doses of 6 mg XM22 and pegfilgrastim and in body weight strata within the treatment groups. Pharmacokinetic and antibody data will be presented.

CONCLUSIONS: Single doses of 6 mg fixed dose of XM22 administered to healthy volunteers were generally well-tolerated with regard to the expected side effect profile and demonstrated increases in absolute neutrophil count and CD34+ cell count. These results supplement data from another study in healthy volunteers in which XM22 was administered in ascending single doses adjusted according to body-weight.