Safety and efficacy of pegfilgrastim in children with cancer receiving myelosuppressive chemotherapy

The myelotoxicity of most chemotherapeutic regimens used to treat children and adolescents with cancer require the use of daily subcutaneous administration of hematological growth factors (mainly granulocyte colony-stimulating factor). Recently, pegfilgrastim (Neulasta), a product with a long half-life, resulting in once-per-cycle dosage, was introduced to prevent neutropenia in adults, and provided safety and efficacy similar to that provided by daily injection of filgrastim. To evaluate retrospectively the use of pegfilgrastim in children with cancer, we conducted a single-center retrospective study evaluating the use of pegfilgrastim in patients over 40 kg, who received chemotherapy for cancer from September 2003 to December 2005. A single subcutaneous injection of pegfilgrastim 100 mu g/kg (maximum dose 6 mg) per chemotherapy cycle in children receiving myelosuppressive chemotherapy was given. One hundred and twenty-six administrations of pegfilgrastim were analyzed in 28 pediatric patients treated for cancer (111 girls, 17 boys) with a median age of 14.5 years (range 12-18 years) and median weight of 50.5 kg (range 40-82 kg). Patients received a median dose of pegfilgrastim of 100 mu g/kg (range 73-117). The median total number of injections per patient was 4 (range 1-14). The incidence of grade 4 neutropenia by cycle was 48%, the mean duration of neutropenia was 3 days (range 1-13 days). The median values of absolute neutrophil count nadir was 0.425 x 10(9)/1 (range 0-9.9 x 10(9)). Febrile neutropenia occurred in 18 of the 126 patients on pegfilgrastim use (14%) with full recovery in all patients. The median total duration of intravenous antibiotic therapy was 5 days (range 2-14 days). Bone pain (four) and headaches (two) were the most frequent adverse events reported. No correlation was found between the administered dose of Neulasta and hematological data. In conclusion, the use of pegfilgrastim was safe and well tolerated in children with cancer treated with myelosuppressive chemotherapy. Safety and efficacy of pegfilgrastim must be compared with filgrastim and evaluated in younger children with lower body weight.