Ifosfamide, mesna, and nephrotoxicity in children

With the increasing use of ifosfamide in pediatric malignancies, nephrotoxicity has emerged as a potentially serious adverse effect, which may be dose-limiting or may cause severe chronic morbidity, including glomerular impairment and/or Fanconi's syndrome. The purpose of this review was (1) to improve the documentation of ifosfamide nephrotoxicity in children, and (2) to consider the possible causative role of ifosfamide metabolites.

(1) A grading system was developed that allowed documentation of the nature and severity of published reports of ifosfamide-induced nephrotoxicity, and evaluation of patient and treatment-related risk factors. (2) The relationship between the pharmacology of ifosfamide/mesna and nephrotoxicity was investigated by examination of published data, especially that concerning the quantitative differences in the metabolism of ifosfamide and its nonnephrotoxic structural isomer, cyclophosphamide.

(1) Examination of 16 published reports (with assessable data from 40 children) demonstrated that ifosfamide-induced nephrotoxicity was associated with a wide range of patient ages and ifosfamide cumulative doses given by different administration schedules. (2) Chloroacetaldehyde, a major metabolite of ifosfamide only, may be at least partly responsible for the renal toxicity of this drug. Although mesna may be capable of detoxifying the toxic metabolite(s), delivery to the renal tubule may not be sufficient to provide adequate protection of tubular glutathione from depletion by the metabolite(s), which results in a failure to prevent nephrotoxicity.

Increased understanding of the interindividual variability in the extent and nature of ifosfamide metabolism, which may be a major determinant of susceptibility to renal damage, may lead to improved use of the drug with less nephrotoxicity.