Investigations on the pharmacokinetics of trofosfamide and its metabolites: first report of 4-hydroxy-trofosfamide kinetics in humans

• Published in: Cancer chemotherapy and pharmacology Vol. 53; no. 6; pp. 496 - 502
• Main Authors: PREISS, Rainer, BAUMANN, Frank, STEFANOVIC, Dragan, NIEMEYER, Ulf, PÖNISCH, Wolfgang, NIEDERWIESER, Dietger
• Format: Journal Article
• Language: English
• Published: Berlin Springer 01-06-2004; Springer Nature B.V
• Subjects: Administration, Oral; Aged; Antineoplastic agents; Antineoplastic Agents, Alkylating - administration & dosage; Antineoplastic Agents, Alkylating - pharmacokinetics; Area Under Curve; Biological and medical sciences; Cyclophosphamide - administration & dosage; Cyclophosphamide - analogs & derivatives; Cyclophosphamide - pharmacokinetics; Female; Humans; Ifosfamide - blood; Lymphoproliferative Disorders - metabolism; Lymphoproliferative Disorders - pathology; Male; Medical sciences; Middle Aged; Pharmacology. Drug treatments; Tumors; Antineoplastic agent; Human; Alkylating agent; Oxazaphosphinane derivatives; Trofosfamide; Ifosfamide; Metabolite; Nitrogen mustard; Organic phosphorodiamidate; Kinetics; Pharmacokinetics; 4-Hydroxytrofosfamide
• ISSN: 0344-5704; 1432-0843
• DOI: 10.1007/s00280-003-0757-y

Trofosfamide (TRO), like cyclophosphamide (CYCLO) and ifosfamide (IFO), is a prodrug oxazaphosphorine derivative that requires hepatic biotransformation to form the cytotoxically active 4-hydroxy derivative (4-hydroxy-TRO). Individual 4-hydroxyoxazaphosphorines and 4-hydroxy-TRO itself have not been demonstrated in humans up to now. For investigation of the principal pharmacokinetics of TRO and its metabolites, six tumour patients (49-65 years of age, Karnofsky index >70%) with normal liver and renal function were given a single oral dose of 600 mg/m(2) TRO. Plasma was sampled using a bedside technique. Individual 4-hydroxyoxazaphosphorines and TRO together with further metabolites were determined by a specially developed HPLC-UV method and a HPLC-MS method, respectively. With a short apparent half-life (1.2 h) and high apparent clearance (Cl/F 4.0 l/min), TRO was very quickly eliminated from plasma and highly converted to its metabolites, mainly 4-hydroxy-TRO and IFO. In relation to the AUC values of TRO (1.0) the following molar quotients were calculated: 1.59 (4-hydroxy-TRO), 0.40 (4-hydroxy-IFO), 6.90 (IFO) and 0.74 (CYCLO). C(max) values were in the range 10-13 micromol/l for TRO, 4-hydroxy-TRO and IFO and in the range 1.5-4.0 micromol/l for CYCLO, 2- and 3-dechloroethyl-IFO and 4-hydroxy-IFO. Kinetic data indicate that 4-hydroxy-IFO is formed by both hydroxylation of TRO and exocyclic N-dechloroethylation of 4-hydroxy-TRO. 4-hydroxy-CYCLO was not detected above the quantification limit of the method. Only mild haemodepressive side effects were observed after oral administration of 600 mg/m(2) TRO. In relation to known data for IFO, TRO is much more 4-hydroxylated than IFO. The high 4-hydroxy-TRO/TRO ratio found suggests that TRO is a promising tumourstatic agent.