412: PEG-filigrastim post-chemotherapy to mobilise PBSC in paediatric oncology patients

There is limited data available on the use of PEG-filigrastim for the mobilisation of peripheral blood stem cells (PBSC) in children. Initial clinical studies using PEG-filgrastim after chemotherapy have shown successful mobilisation of CD34+ cells in adults with haematological malignancies. PEG-filgrastim has been used at Children’s Hospital at Westmead (CHW) since December 2002. At CHW we mobilise and harvest PBSC’s from approximately 35 patients per annum following colony stimulating factors, predominantly GCSF +/- chemotherapy. We observed that in 5 patients after routine chemotherapy, PEG-filigrastim mobilised sufficient numbers of CD34+ cells for collection, with impressive CD34 counts both in the blood and in the final CD34/kg collected.This has led to a 2 year prospective observational study since July 2006 to investigate the numbers of CD34+ cells in the blood of children following administration of PEG-filigrastim post chemotherapy. The aim is to determine the correlation between the recovering white cell count (WCC) and increasing CD34+ count. This will guide the commencement of PBSC harvesting after the use of PEG-filigrastim to mobilise PBSC’s. All children in the oncology unit who are already scheduled to receive PEG-filgrastim are eligible. The dose of PEG-filgrastim is based on weight. It is not administered to children <10kg.Twelve patients have been enrolled on the study since its commencement in July 2006.These patients received subcutaneous PEG-filigrastim following protocol driven chemotherapy. Five of the twelve patients achieved a peripheral CD34 count of > 20 × 106/ml which is the minimum CD34 count required at CHW for commencement of PBSC harvest. Three of the 12 patients did not achieve a peripheral CD34 count > 8 × 106/ml over a 20 day period with increasing WCC, the average CD34 count being <1 × 106/ml. Four patients are awaiting count recovery post chemotherapy + PEG-filigrastim at time of report.Early results from this study indicate that PEG-filigrastim may be considered for patients requiring PBSC harvest in the paediatric setting. The once only injection allows greater compliance with paediatric patients.Optimum timing remains a question which should be answered with continued accrual of patient numbers into the study. There is limited data available on the use of PEG-filigrastim for the mobilisation of peripheral blood stem cells (PBSC) in children. Initial clinical studies using PEG-filgrastim after chemotherapy have shown successful mobilisation of CD34+ cells in adults with haematological malignancies. PEG-filgrastim has been used at Children’s Hospital at Westmead (CHW) since December 2002. At CHW we mobilise and harvest PBSC’s from approximately 35 patients per annum following colony stimulating factors, predominantly GCSF +/- chemotherapy. We observed that in 5 patients after routine chemotherapy, PEG-filigrastim mobilised sufficient numbers of CD34+ cells for collection, with impressive CD34 counts both in the blood and in the final CD34/kg collected. This has led to a 2 year prospective observational study since July 2006 to investigate the numbers of CD34+ cells in the blood of children following administration of PEG-filigrastim post chemotherapy. The aim is to determine the correlation between the recovering white cell count (WCC) and increasing CD34+ count. This will guide the commencement of PBSC harvesting after the use of PEG-filigrastim to mobilise PBSC’s. All children in the oncology unit who are already scheduled to receive PEG-filgrastim are eligible. The dose of PEG-filgrastim is based on weight. It is not administered to children <10kg. Twelve patients have been enrolled on the study since its commencement in July 2006.These patients received subcutaneous PEG-filigrastim following protocol driven chemotherapy. Five of the twelve patients achieved a peripheral CD34 count of > 20 × 106/ml which is the minimum CD34 count required at CHW for commencement of PBSC harvest. Three of the 12 patients did not achieve a peripheral CD34 count > 8 × 106/ml over a 20 day period with increasing WCC, the average CD34 count being <1 × 106/ml. Four patients are awaiting count recovery post chemotherapy + PEG-filigrastim at time of report. Early results from this study indicate that PEG-filigrastim may be considered for patients requiring PBSC harvest in the paediatric setting. The once only injection allows greater compliance with paediatric patients. Optimum timing remains a question which should be answered with continued accrual of patient numbers into the study.