Pegfilgrastim

▴ Pegfilgrastim is a covalent conjugant of filgrastim (a recombinant human granulocyte colony-stimulating factor) and monomethoxypolyethylene glycol. It is administered as a single dose per myelosuppressive chemotherapy cycle to decrease the incidence of infection, as manifest by febrile neutropenia, in patients with nonmyeloid cancer. ▴ Pegfilgrastim increases the terminal elimination half-life and decreases the apparent serum clearance of the drug in patients with nonmyeloid cancer. Serum concentrations of pegfilgrastim remain elevated during neutropenia but decline when the neutrophil count increases. ▴ In phase III trials in patients with breast cancer and in a phase II trial in patients with non-Hodgkin’s lymphoma or Hodgkin’s disease, the mean duration of grade 4 neutropenia and the time to absolute neutrophil recovery during cycle 1 of chemotherapy was similar in recipients of single-dose pegfilgrastim or daily filgrastim. ▴ In the larger of two phase III trials in patients with breast cancer, the incidence of febrile neutropenia over four cycles of chemotherapy was significantly lower in recipients of single-dose pegfilgrastim than that in recipients of daily injections of filgrastim. Moreover, the mean duration of grade 4 neutropenia in cycles 2 to 4 of chemotherapy was significantly lower in recipients of pegfilgrastim than that in recipients of daily filgrastim. ▴ In comparative trials, there were no differences in the incidence and severity of adverse events, including skeletal pain, between single-dose pegfilgrastim and daily filgrastim in patients with nonmyeloid cancer receiving myelosuppressive chemotherapy.