Pharmacokinetics of treosulfan and its active monoepoxide in pediatric patients after intravenous infusion of high-dose treosulfan prior to HSCT

Pro-drug treosulfan (TREO) is currently evaluated in randomized phase III clinical trials as a conditioning agent prior to HSCT. In the present paper pharmacokinetics of both TREO and its biologically active monoepoxide (S,S-EBDM) was investigated in pediatric patients for the first time. The studies were carried out in 16 children (median age 7.5 years) undergoing TREO-based preparative regimen prior to HSCT, who received 10, 12 or 14 g/m2 of the drug as a 1 h or 2 h intravenous infusion. Plasma concentrations of TREO as well as S,S-EBDM were determined using the validated HPLC–MS/MS method. The changes in S,S-EBDM concentration over time followed TREO levels. The area under the curve (AUC) of TREO was 100-fold higher than AUC of S,S-EBDM. No statistically significant dependency of the dose-normalized AUC of either TREO or S,S-EBDM on the patients’ age and body surface area was stated. Moreover, plasma Cmax as well as AUC of S,S-EBDM demonstrated linear correlation with the Cmax and AUC of TREO, respectively. The biological half-lives of TREO and S,S-EBDM were similar. This indicates that S,S-EBDM was completely eliminated from the patients’ blood within relatively short time, comparable to TREO.

Graphical abstractIn 16 pediatric patients, plasma concentrations of S,S-EBDM were much lower in comparison to pro-drug treosulfan but biological half-lives of the both compounds were similar.Figure optionsDownload full-size imageDownload high-quality image (99 K)Download as PowerPoint slide