Incidence and etiology of ifosfamide nephrotoxicity: report of a meeting held in Rhodes, Greece, October 3, 1991, sponsored by Asta Medica, Frankfurt, Germany

Drug-induced acid-base disorders

The incidence of acid-base disorders (ABDs) is high, especially in hospitalized patients. ABDs are often indicators for severe systemic disorders. In everyday clinical practice, analysis of ABDs must be performed in a standardized manner. Highly sensitive diagnostic tools to distinguish the various ABDs include the anion gap and the serum osmolar gap. Drug-induced ABDs can be classified into five different categories in terms of their pathophysiology: (1) metabolic acidosis caused by acid overload, which may occur through accumulation of acids by endogenous (e.g., lactic acidosis by biguanides, propofol-related syndrome) or exogenous (e.g., glycol-dependant drugs, such as diazepam or salicylates) mechanisms or by decreased renal acid excretion (e.g., distal renal tubular acidosis by amphotericin B, nonsteroidal anti-inflammatory drugs, vitamin D); (2) base loss: proximal renal tubular acidosis by drugs (e.g., ifosfamide, aminoglycosides, carbonic anhydrase inhibitors, antiretrovirals, oxaliplatin or cisplatin) in the context of Fanconi syndrome; (3) alkalosis resulting from acid and/or chloride loss by renal (e.g., diuretics, penicillins, aminoglycosides) or extrarenal (e.g., laxative drugs) mechanisms; (4) exogenous bicarbonate loads: milk-alkali syndrome, overshoot alkalosis after bicarbonate therapy or citrate administration; and (5) respiratory acidosis or alkalosis resulting from drug-induced depression of the respiratory center or neuromuscular impairment (e.g., anesthetics, sedatives) or hyperventilation (e.g., salicylates, epinephrine, nicotine).

Use of precision-cut renal cortical slices in nephrotoxicity studies

1.Unlike cell lines and primary cells in culture, precision-cut tissue slices remain metabolically differentiated for at least 24-48 h and allow to study the effect of xenobiotics during short-term and long-term incubations. 2.In this article, we illustrate the use of such an experimental model to study the nephrotoxic effects of (i) chloroacetaldehyde, a metabolite of the anticancer drug ifosfamide, (ii) of cobalt chloride, a potential leakage product of the cobalt-containing nanoparticles, and (iii) of valproate, a widely used antiepileptic drug. 3.Since all the latter test compounds, like many toxic compounds, negatively interact with cellular metabolic pathways, we also illustrate our biochemical toxicology approach in which we used not only enzymatic but also carbon 13 NMR measurements and mathematical modelling of metabolic pathways. 4.This original approach, which can be applied to any tissue, allows to predict the nephrotoxic effects of milligram amounts of test compounds very early during the research and development processes of drugs and chemicals. This approach, combined with the use of cells that retain their in vivo metabolic properties and, therefore, are predictive, reduces the risk, the time and cost of such processes.

Growth impairment after ifosfamide-induced nephrotoxicity in children

BACKGROUND

The goal of this study was to analyze long-term consequences of ifosfamide-induced nephrotoxicity on growth and renal function in children treated for cancer.

PROCEDURE

In a retrospective study, departments for pediatric oncology and nephrology in Germany, Austria, and Switzerland were asked to report patients with serious long-term nephrotoxicity after ifosfamide-treatment. Data at first appearance of renal dysfunction and at the last renal examination were collected using a standardized questionnaire.

RESULTS

Fifty-nine patients with tubulopathy (35 severe, 24 moderate) following ifosfamide therapy were eligible for analysis of long-term outcome (median follow-up 4 years, range 1.1 to 12.9). Median height standard deviation score was significantly reduced at renal diagnosis, and at last renal examination (-1.7 and -2.1 respectively, P < 0.01 at each point in time). Patients with tubulopathy also had stunted growth in comparison with a control group of cancer patients without renal disease (mean difference at last examination: 7.3 cm (95% confidence interval: 2.5 to 12.1 cm). In patients with severe tubulopathy, glomerular filtration rate deteriorated significantly over time. End-stage renal disease was reported in one patient only, not solely caused by ifosfamide.

CONCLUSION

Depending on the extent of tubular dysfunction, patients with ifosfamide-induced nephrotoxicity experienced significant growth impairment and a slow decline in glomerular filtration rate.

Ifosfamide-induced nephrotoxicity in 593 sarcoma patients: a report from the Late Effects Surveillance System

BACKGROUND

Ifosfamide is widely used in paediatric oncology, but its use is limited by nephrotoxic side effects. The aim of this study was to evaluate the incidence and risk factors of tubulopathy, with special emphasis on the influence of age, where different findings have been published so far.

PROCEDURE

Five hundred ninety three children and adolescents treated for Ewing, osteo- or soft-tissue sarcoma (median age at diagnosis: 11.7 years) were prospectively investigated for nephrotoxicity in the Late Effects Surveillance System (LESS) study. Tubulopathy was diagnosed in case of continuing hypophosphatemia and proteinuria.

RESULTS

After a median follow up of 19 months, 27 patients (4.6%; 95% CI: 3.0-6.6%) had newly developed tubulopathy. This incidence was 0.4% (95% CI: 0-2.4%) in patients treated with a cumulative ifosfamide dose of < or =24 g/m2, 6.5% (95% CI: 3.6-10.7%) after 24-60 g/m2, and 8.0% (95% CI: 4.2-13.6%) after > or = 60 g/m2. In multivariate analysis, children younger than 4 years at time of diagnosis had an 8.7-fold (95% CI: 3.5-21.8) higher risk for tubulopathy than older patients. Neither carboplatin treatment nor abdominal irradiation showed any significant influence.

CONCLUSION

Ifosfamide-induced nephrotoxicity was found in 4.6% of patients. Risk factors were the cumulative ifosfamide dose and young age at treatment.

Human kidney tubules detoxify chloroacetaldehyde, a presumed nephrotoxic metabolite of ifosfamide

The nephrotoxic effects of the antineoplastic drug ifosfamide have been attributed to its hepatic metabolite chloroacetaldehyde. The effects of chloroacetaldehyde on isolated human kidney cortex tubules metabolizing lactate (a physiologic substrate in human kidneys) were investigated. At concentrations of > or =0.5 mM, chloroacetaldehyde was toxic to the human kidney tubules, as demonstrated by a dramatic decrease in cellular ATP levels and a large increase in lactate dehydrogenase release; chloroacetaldehyde also stimulated pyruvate accumulation and inhibited lactate removal and glucose synthesis. These effects, which were associated with incomplete disappearance of chloroacetaldehyde and extensive depletion of the cellular CoA, acetyl-CoA, and glutathione contents, were prevented by the addition of thiol-protecting drugs (mesna and amifostine). Human kidney tubules were demonstrated to metabolize chloroacetaldehyde at high rates, presumably via aldehyde dehydrogenase, which is very active in human kidneys. Carbon-13 nuclear magnetic resonance spectroscopy measurements indicated that human kidney tubules converted [2-(13)C]chloroacetaldehyde to [2-(13)C]chloroacetate, the further metabolism of which was very limited. At equimolar concentrations, chloroacetate was much less toxic than chloroacetaldehyde, indicating that chloroacetate synthesis from chloroacetaldehyde by human kidney tubules represents a detoxification mechanism that could play a role in vivo in preventing or limiting the nephrotoxic effects observed during ifosfamide therapy.

Malignancy and renal disease

A variety of renal diseases and electrolyte disorders may be associated with various malignancies or with treatment of malignancy with chemotherapeutic drugs or radiation. This article reviews renal disease in cancer patients, which constitutes a major source of morbidity and mortality.

Renal function following combination chemotherapy with ifosfamide and cisplatin in patients with osteogenic sarcoma

BACKGROUND

Ifosfamide and cisplatin are active agents that are currently used in the treatment of osteosarcoma. Nephrotoxicity has been reported following their use in combination and alone. This study evaluates renal function in children and adolescents (median age 16 years) at least 3 months following completion of a chemotherapy regimen which included 54 g/m2 ifosfamide, 360 mg/m2 cisplatin, doxorubicin, and high-dose methotrexate.

PROCEDURE

Mean glomerular filtration rate (GFR) was determined by inulin or iothalamate clearance; proximal tubular function was evaluated by measuring fractional excretion of glucose (FEglu), tubular maximum phosphate reabsorption per GFR (TMP/GFR), FE of urate, and 24-hour amino acid excretion. Distal tubular function was evaluated by 24-hour urinary calcium, FE of magnesium, and urinary osmolality after water deprivation. Twenty-four-hour urinary protein excretion was measured.

RESULTS

The mean GFR was 97 ml/min/1.73 m2. Although 10 of 24 patients had GFRs lower than normal, the lowest value was only 22% below the lower limit of normal and would not account for any clinical compromise. Proximal tubular function evaluation revealed normal FEglu, normal mean TMP/GFR values, and high FE of urate (1 5.7%). Two of twenty-four patients were shown to have mild generalized aminoaciduria. Distal tubular function evaluation showed normal 24-hour urinary calcium levels (mean 3.4 mg/kg) and FE of magnesium as well as normal urinary osmolality. Twenty-four-hour urinary protein excretion was normal in all patients.

CONCLUSIONS

The lack of clinically significant renal abnormalities observed in patients who received combination chemotherapy with ifosfamide and cisplatin for osteosarcoma is encouraging for future osteosarcoma protocol development.

Ifosfamide nephrotoxicity in children: histopathological features in two cases

We report on two children with rhabdomyosarcoma who received ifosfamide as part of their chemotherapy schedule. Both children subsequently developed severe ifosfamide-induced nephrotoxicity, necessitating electrolyte supplementation. We describe the histopathological findings of renal biopsies performed in these children after the onset of renal dysfunction and comment on the possible mechanisms involved in ifosfamide nephrotoxicity.

A prospective evaluation of ifosfamide-related nephrotoxicity in children and young adults

BACKGROUND

Ifosfamide has been associated with proximal renal tubular dysfunction resembling Fanconi-like syndrome and leading to rickets in young children. The characteristic manifestations of this nephrotoxicity include phosphaturia and hypophosphatemia, glycosuria, aminoaciduria, renal tubular acidosis, and urinary loss of low molecular weight serum proteins. However, the relationship between acute ifosfamide nephrotoxicity, which is frequently subclinical, and long term renal damage is unclear. In this prospective study, the laboratory features of ifosfamide-induced acute nephrotoxicity were characterized further and correlated with the development of chronic nephropathy.

METHODS

The renal function of newly diagnosed children and young adults with high risk sarcomas was followed during therapy with a high dose ifosfamide-containing regimen. Serum and urine were collected regularly immediately before and after 5-day cycles of ifosfamide throughout treatment for determination of the fractional excretion of electrolytes (sodium, potassium, phosphate, magnesium, calcium) and glucose and urinary excretion of amino acids and beta 2-microglobulin.

RESULTS

Significant changes in the renal threshold of phosphate excretion, the fractional excretion of calcium and glucose, and the urinary excretion of beta 2-microglobulin were observed when comparing pretreatment values with those at the end of a 5-day treatment cycle. The median renal threshold of phosphate excretion decreased from 1.22 to 0.82 mmol/L (P < 0.0001). The median fractional excretions of calcium and glucose increased from 1.05% to 1.68% (P < 0.0001) and 0.05% to 0.08% (P = 0.0006), respectively. Beta 2-microglobulin excretion increased by 70-fold from 0.02 to 1.42 mg/mmol (P < 0.0001). Except for glucose and beta 2-microglobulin excretion, renal parameters returned to baseline before the next ifosfamide treatment cycle. Acute aminoaciduria was observed in 21 of 23 patients. Chronic nephrotoxicity, as defined by the development of a Fanconi-like syndrome or chronic tubular electrolyte loss requiring oral supplementation, developed in the three patients with the highest urinary excretion of beta 2-microglobulin after ifosfamide therapy.

CONCLUSIONS

Prospectively, high dose ifosfamide was associated with a 4% incidence of Fanconi-like syndrome; however, evidence of acute reversible subclinical nephrotoxicity was observed for all patients. Severe beta 2-microglobulinuria appeared to be a prognostic laboratory indicator for the development of chronic nephrotoxicity.

Interactions of drugs with the developing kidney

Interactions between drugs and the kidney are necessary for renal drug elimination, metabolism, and occasionally for therapeutic effect. These interactions may result also in renal toxicity. Understanding the kidney's role in drug-handling helps the clinician to be aware of potential drug interactions and toxicity. Drug disposition, elimination, and toxicity may differ with development and are to be considered when prescribing drugs for children. Nephrotoxicity associated with drugs, although common, is usually reversible with discontinuation of the drug; however, when drug therapy with a well-known nephrotoxic drug (e.g., cisplatin) is necessary, pharmacologic modulators may play a role in limiting the associated nephrotoxicity.