Pharmacokinetics of high-dose etoposide administered in combination with fractionated total-body irradiation as conditioning for allogeneic hematopoietic stem cell transplantation in children with acute lymphoblastic leukemia.

Etoposide (VP-16) is one of the most widely used antitumor agents in pediatric oncology as well as chemotherapeutic agents used in conditioning regimen prior to allo-HSCT for childhood ALL. This study included 21 children with ALL who underwent allo-HSCT after conditioning with FTBI and high-dose of VP-16 (60 mg/kg) given intravenously as single four-h infusion on day -3 (n=2) or day -4 (n=19) prior to allo-HSCT. Blood samples were collected at defined time intervals until 120 h elapsed from the end of infusion. VP-16 plasma concentrations were determined using validated HPLC method. Three-compartment model was assumed for assessing PK parameters of VP-16. The median value of VP-16 C(max) measured at the end of infusion was 188.0 µg/mL (range 148.0-407.0 µg/mL). Out of 21 studied children, VP-16 was still detectable in 17 patients 72 h (median concentration 0.31 µg/mL) and in eight patients 96 h (median concentration 0.31 µg/mL) after the end of infusion. VP-16 concentration 96 h after the end of infusion was positively correlated with VP-16 AUC and negatively correlated with VP-16 CL normalized to body weight.

[Results of immunosupressive therapy in children with severe aplastic anaemia. Report of the Polish Paediatric Haematology Group]. / Wyniki leczenia ciezkiej postaci anemii aplastycznej u dzieci. Raport Polskiej pediatrycznej grupy do spraw nienowotworowych chorób ukladu krwiotwórczego.

INTRODUCTION: Bone marrow transplantation from HLA identical family donors is the treatment of choice for children with severe aplastic anaemia (SAA). When there is no donor available, combined immunosuppressive therapy is given. AIM: evaluation of results of immunosupressive therapy in children with severe aplastic anaemia. MATERIAL AND METHODS: SAA was diagnosed in 105 children (42 girls, 73 boys), aged 2-18 years, in the eleven haematological centres in Poland, between 1993-2007. All patients received the Severe Aplastic Anaemia Working Party of the EBMT protocol which included: antilymphocyte globulin or antithymocyte globulin, cyclosporin A, prednisolone. Granulocyto- or granulocytomacrophagic-cell stimulation factor was additionally administered during deep neutropenia. Haematological response was evaluated on day 84 or 112 and 180 of the therapy. RESULTS: complete remission occurred in 53 patients (51.5%), partial remission in 27 (24.7%), no response was obtained in 25 children (23.8%) on day 180, of the therapy. Period of observation was from 12 months to 12.5 years. During this time relapse occurred in 10 patients (9.5%). We observed 22 deaths: 8 early, during the first 3 months of IS and 14 after the first 3 months of immunosuppresive therapy (IS). At present 70 children (66.6%) are in first remission with lasts from 12 months to 12.5 years. The survival at 12.5-years is 78.6%. During the 12.5 years of follow-up we had two cases with a late clonal complication (PNH and MDS). Transformation to acute nonlymphoblastic leukaemia was observed in two of our patients. CONCLUSIONS: 1. Immunosuppresive therapy (IS) in children with SAA, without bone marrow family donors, is more effective after introduction of combined IS (12.5 years survival in this study was 80% for children with very severe aplastic anaemia (v SAA). 2. In our studies among the children followed up after IS therapy, there were: 1 case of periodic nocturnal haemoglobinuria (PNH), 1 case of myelodysplastic syndrome (MDS) and 2 cases of myeloid leukaemia (probability of incidence was 3.8%).

Determination of treosulfan in plasma and urine by HPLC with refractometric detection; pharmacokinetic studies in children undergoing myeloablative treatment prior to haematopoietic stem cell transplantation.

A direct and selective HPLC method with refractometric detection was worked out for determination of treosulfan in plasma and urine of children. Before injection onto reverse phase column plasma samples with treosulfan and barbital (I.S.) were clarified using filtration. The mobile phase was composed of phosphate buffer, pH 5 and acetonitrile. The linear range of the standard curve of treosulfan spanned concentrations of 10.0-2000.0 microg/ml and 50.0-10000.0 microg/ml in plasma and urine, respectively, and covered the levels found in biological fluids after infusion of the drug. The limit of detection amounted to 5 microg/ml for plasma and 25 microg/ml for urine. Intra- and inter-day precision and accuracy of the measurement fulfilled analytical criteria accepted in pharmacokinetic studies. Recovery of treosulfan as well as stability in biological fluids was also calculated. The validated method was successfully applied in pharmacokinetic studies of treosulfan administered to children prior to haematopoietic stem cell transplantation. Differences between pharmacokinetics of treosulfan in children and adults were also studied.