Retrospective Comparison of Neutropenia in Children With Ewing Sarcoma Treated With Chemotherapy and Granulocyte Colony-Stimulating Factor (G-CSF) or Pegylated G-CSF

Background: Filgrastim is an effective granulocyte colony-stimulating factor (G-CSF) used to reduce periods of neutropenia and the risk of infection after chemotherapy courses. Pegfilgrastim is a pegylated filgrastim with a longer plasma half-life that is administered once per cycle. Objective: The aim of this study was to compare the efficacy of pegfilgrastim and filgrastim administered after chemotherapy in children with Ewing sarcoma. Methods: We performed a retrospective chart review of pediatric patients with Ewing sarcoma. Every patient received both types of G-CSF in different treatment courses of chemotherapy, which consisted of vincristine, ifosfamide, doxorubicin, and etoposide (VIDE); vincristine, actinomycin D, and ifosfamide (VAI); or vincristine, actinomycin D, and cyclophosphamide (VAC). A single injection of pegfilgrastim 100 mu g/kg SC or a daily injection of filgrastim 5 to 10 mu g/kg SC was administered 48 to 72 hours after the completion of chemotherapy. The following data were collected from the medical charts: proportion of chemotherapy courses with grade 4 neutropenia, duration of grade 4 neutropenia, proportion with severe neutropenia, duration of severe neutropenia, proportion with febrile neutropenia, duration of antibiotic treatment, duration of hospitalization, and percentage of patients receiving transfusion. Grade 4 neutropenia was defined as an absolute neutrophil count of <500 x 10(9)/L; severe neutropenia was defined as a count of <200 x 10(9)/L. Adverse events were collected from the medical charts. Results: Twenty children were included (13 girls and 7 boys). The patients' median age was 12.8 years (range, 9-17 years) and median weight was 45.2 kg (range, 28-90 kg). A total of 178 chemotherapy courses (108 VIDE; 70 VAI or VAC) were administered and evaluated, including 134 courses with pegfilgrastim and 44 Courses with filgrastim. Considering all types of chemotherapy combined, those courses in which pegfilgrastim was used were associated with a significantly lower incidence of severe neutropenia (0.21. vs 0.85; P = 0.03), a shorter duration of severe neutropenia (0.49 vs 2.36 days; P = 0.01), and a shorter duration of antibiotic treatment (1.07 vs 4.22 days; P = 0.03) compared with courses treated with filgrastim. No statistically significant differences were observed for the proportion and duration of grade 4 neutropenia, proportion of febrile neutropenia, duration of hospitalization, or red blood cell and platelet transfusions. Adverse effects were few and comparable between pegfilgrastim and filgrastim. Conclusions: In this retrospective chart review of children with Ewing sarcoma, using pegfilgrastim after chemotherapy courses was associated with significantly reduced frequency and shorter duration of severe neutropenia compared with those courses followed by filgrastim. Randomized controlled trials are needed to confirm these preliminary observations. (Clin Ther. 2009;31 [Theme Issue]: 2388-2395) (C) 2009 Excerpta Medica Inc.