Safety and efficacy of pegfilgrastim in pediatric solid tumor patients (pts).

Abstract

e20007 Background: Progressive intensification of chemo-radiotherapy regimens has led to improved outcome of children with solid tumors. Marrow toxicity and neutropenia have become the main dose-limiting toxicities, often resulting in life-threatening infectious complications. Hematopoietic growth factors were introduced into clinical practice to minimize these complications. Recently Pegfilgrastim, a PEG-conjugated form of r-metHuG-CSF (filgrastim) with much longer serum half-life and a comparable safety and efficacy profile in adults has become available. We describe our retrospective institutional experience with Pegfilgrastim after myelosuppressive chemotherapy in children with solid tumours. Methods: Pts received a single subcutaneous injection of Pegfilgrastim, administered 72-96 hours after the completion of chemotherapy, at the dose of 100 μ g/kg (in children < 40 kg of weight) or 6 mg flat dose (in pts > 40 kg). Diagnoses were: CNS tumours (3), neuroblastoma (6), rhabdomyosarcoma (3), Ewing sarcoma (6), renal cancer (1) and other solid tumors (3). We analyzed: incidence and duration of grade IV neutropenia, presence and length of fever, incidence of bacteremia, absolute neutrophil count (ANC) nadir, number of platelet (Plt) and packed red blood cell (PRBC) transfusions, PBSC harvests and incidence of adverse events. Results: Between February 2008 and April 2009, 22 patients, M/F 13/9, median age 70 months (range 26-191), median body weight 19.2 kg (range 14-60.5) received 80 doses. We observed: grade IV neutropenia in 86% of courses, median ANC nadir of 0.03×109/L (range 0- 3.360×109/L), median recovery time of 14 days (range 8-30) and median duration of grade IV neutropenia of 4 days (range 0-16). Febrile neutropenia occurred in 58% of courses, with 7 cases of documented sepsis; patients received 88 PRBC transfusions and 148 Plt transfusions. 83% of PBSC harvests were successful, with a median harvest of 6,7 × 106 CD34+ cells/kg (range 2.16-60); no significant adverse events were recorded. Conclusions: A single dose of pegfilgrastim per chemotherapy course is as safe and effective as daily filgrastim in children with solid malignancies both in enhancing neutrophil recovery and in CD34+ mobilization. No significant financial relationships to disclose.