Nephrotoxicity after ifosfamide

Renal toxicity of ifosfamide in children with cancer: an exploratory study integrating aldehyde dehydrogenase enzymatic activity data and a wide-array urinary metabolomics approach

BACKGROUND

Ifosfamide is a major anti-cancer drug in children with well-known renal toxicity. Understanding the mechanisms underlying this toxicity could help identify children at increased risk of toxicity.

METHODS

The IFOS01 study included children undergoing ifosfamide-based chemotherapy for Ewing sarcoma or rhabdomyosarcoma. A fully evaluation of renal function was performed during and after chemotherapy. Proton nuclear magnetic resonance (NMR) and conventional biochemistry were used to detect early signs of ifosfamide-induced tubulopathy. The enzymatic activity of aldehyde dehydrogenase (ALDH) was measured in the peripheral blood lymphocytes as a marker of ifosfamide-derived chloroacetaldehyde detoxification capacity. Plasma and urine concentrations of ifosfamide and dechloroethylated metabolites were quantified.

RESULTS

The 15 participants received a median total ifosfamide dose of 59 g/m2 (range: 24-102), given over a median of 7 cycles (range: 4-14). All children had acute proximal tubular toxicity during chemotherapy that was reversible post-cycle, seen with both conventional assays and NMR. After a median follow-up of 31 months, 8/13 children presented overall chronic toxicity among which 7 had decreased glomerular filtration rate. ALDH enzymatic activity showed high inter- and intra-individual variations across cycles, though overall activity looked lower in children who subsequently developed chronic nephrotoxicity. Concentrations of ifosfamide and metabolites were similar in all children.

CONCLUSIONS

Acute renal toxicity was frequent during chemotherapy and did not allow identification of children at risk for long-term toxicity. A role of ALDH in late renal dysfunction is possible so further exploration of its enzymatic activity and polymorphism should be encouraged to improve the understanding of ifosfamide-induced nephrotoxicity.

Chapter 1: Evaluation of kidney function in patients undergoing anticancer drug therapy, from clinical practice guidelines for the management of kidney injury during anticancer drug therapy 2022

The prevalence of CKD may be higher in patients with cancer than in those without due to the addition of cancer-specific risk factors to those already present for CKD. In this review, we describe the evaluation of kidney function in patients undergoing anticancer drug therapy. When anticancer drug therapy is administered, kidney function is evaluated to (1) set the dose of renally excretable drugs, (2) detect kidney disease associated with the cancer and its treatment, and (3) obtain baseline values for long-term monitoring. Owing to some requirements for use in clinical practice, a GFR estimation method such as the Cockcroft-Gault, MDRD, CKD-EPI, and the Japanese Society of Nephrology's GFR estimation formula has been developed that is simple, inexpensive, and provides rapid results. However, an important clinical question is whether they can be used as a method of GFR evaluation in patients with cancer. When designing a drug dosing regimen in consideration of kidney function, it is important to make a comprehensive judgment, recognizing that there are limitations regardless of which estimation formula is used or if GFR is directly measured. Although CTCAEs are commonly used as criteria for evaluating kidney disease-related adverse events that occur during anticancer drug therapy, a specialized approach using KDIGO criteria or other criteria is required when nephrologists intervene in treatment. Each drug is associated with the different disorders related to the kidney. And various risk factors for kidney disease associated with each anticancer drug therapy.

Nephrotoxicity associated with anticancer agents: perspective on onconephrology from nephrologists

Nephrotoxicity is one of the most important complications in cancer patients. In particular, acute kidney injury (AKI) is known to be associated with discontinuing effective oncological treatments, longer hospitalizations, increased costs, and a higher risk of death. In addition to acute kidney injury, clinical signs associated with nephrotoxicity during treatment with anticancer agents include chronic kidney disease, proteinuria, hypertension, electrolyte abnormalities, and other characteristic manifestations. Many of these signs are caused both by cancer treatment as well as by cancer itself. Therefore, it is important to carefully recognize whether the underlying causes of renal impairment in cancer patients are cancer-related, treatment-related, or both. This review describes the epidemiology and pathophysiology of anticancer agent-induced acute kidney injury, proteinuria, hypertension, and other characteristic manifestations.

Acute Kidney Injury in Critically Ill Patients with Cancer

Advances in cancer therapy have significantly improved overall patient survival; however, AKI remains a common complication in patients with cancer, occurring in anywhere from 11% to 22% of patients, depending on patient-related or cancer-specific factors. Critically ill patients with cancer as well as patients with certain malignancies (e.g., leukemias, lymphomas, multiple myeloma, and renal cell carcinoma) are at highest risk of developing AKI. AKI may be a consequence of the underlying malignancy itself or from the wide array of therapies used to treat it. Cancer-associated AKI can affect virtually every compartment of the nephron and can present as subclinical AKI or as overt acute tubular injury, tubulointerstitial nephritis, or thrombotic microangiopathy, among others. AKI can have major repercussions for patients with cancer, potentially jeopardizing further eligibility for therapy and leading to greater morbidity and mortality. This review highlights the epidemiology of AKI in critically ill patients with cancer, risk factors for AKI, and common pathologies associated with certain cancer therapies, as well as the management of AKI in different clinical scenarios. It highlights gaps in our knowledge of AKI in patients with cancer, including the lack of validated biomarkers, as well as evidence-based therapies to prevent AKI and its deleterious consequences.

Conventional Chemotherapy Nephrotoxicity

Conventional chemotherapies remain the mainstay of treatment for many malignancies. Kidney complications of these therapies are not infrequent and may have serious implications for future kidney function, cancer treatment options, eligibility for clinical trials, and overall survival. Kidney adverse effects may include acute kidney injury (via tubular injury, tubulointerstitial nephritis, glomerular disease and thrombotic microangiopathy), long-term kidney function loss and CKD, and electrolyte disturbances. In this review, we summarize the kidney complications of conventional forms of chemotherapy and, where possible, provide estimates of incidence, and identify risk factors and strategies for kidney risk mitigation. In addition, we provide recommendations regarding kidney dose modifications, recognizing that these adjustments may be limited by available supporting pharmacokinetic and clinical outcomes data. We discuss management strategies for kidney adverse effects associated with these therapies with drug-specific recommendations. We focus on frequently used anticancer agents with established kidney complications, including platinum-based chemotherapies (cisplatin, carboplatin, oxaliplatin), cyclophosphamide, gemcitabine, ifosfamide, methotrexate and pemetrexed, among others.

19-year-old Woman with Intermittent Weakness

Introduction

Systemic weakness is a common chief complaint of patients presenting to the emergency department (ED). A well thought out approach to the assessment and workup of these patients is key to diagnostic accuracy and definitive therapy.

Case Presentation

In this case, a 19-year-old female presented to the ED with generalized weakness and near syncope. She had global weakness in her extremities and multiple electrolyte abnormalities.

Discussion

This case takes the reader through the differential diagnosis and evaluation of a patient with weakness and profound electrolyte derangements. It includes a discussion of the diagnostic studies and calculations that ultimately led to the patient’s diagnosis.

Ifosfamide-induced nephrogenic diabetes insipidus responsive to supraphysiologic doses of intravenous desmopressin

Nephrogenic diabetes insipidus (DI) refers to the reduction in the ability of the kidney to concentrate urine, which can be caused by partial or complete resistance at the site of action of anti-diuretic hormone (ADH) in the collecting tubules. Ifosfamide-induced nephrogenic DI typically occurs concomitantly in patients who have other signs of tubular toxicity consistent with Fanconi syndrome including glucosuria, aminoaciduria, and hypophosphatemia. We present a case of a 36-year-old female with recurrent synovial cell sarcoma of the pleural membranes, treated with ifosfamide-based chemotherapy, who was admitted to the hospital for the management of polyuria, hypotension, as well as electrolyte derangements including hypokalemia, hypophosphatemia and non-anion gap metabolic acidosis, 1 week after receiving a cumulative ifosfamide dose of 7.5 g/m². Nephrogenic DI was indicated by polyuria as well as a urine osmolality to plasma osmolality ratio of less than 1.5 following a trial of intravenous desmopressin, but the patient’s acute kidney injury on presentation precluded the early employment of thiazides and non-steroidal anti-inflammatory drugs (NSAIDs). Instead, the patient’s polyuria and urine osmolality improved only after the administration of repetitive supraphysiologic doses of intravenous desmopressin. Our case reiterates that patients with non-hereditary nephrogenic DI may have partial rather than complete resistance to ADH and highlights that desmopressin may be considered in patients with ifosfamide-induced nephrogenic DI to prevent severe volume depletion, especially in patients who have persistent symptomatic polyuria despite maintaining a careful fluid balance and pharmacological therapy with NSAIDs and diuretics, or if the patient’s clinical condition precludes the use of these strategies.

Melatonin ameliorates the drug induced nephrotoxicity: Molecular insights

BACKGROUND

Drug-induced nephrotoxicity is a frequent adverse event that can lead to acute or chronic kidney disease and increase the healthcare expenditure. It has high morbidity and mortality incidence in 40-70% of renal injuries and accounts for 66% cases of renal failure in elderly population.

OBJECTIVE

Amelioration of drug-induced nephrotoxicity has been long soughed to improve the effectiveness of therapeutic drugs. This study was conducted to review the melatonin potential to prevent the pathogenesis of nephrotoxicity induced by important nephrotoxic drugs.

METHODS

We analyzed the relevant studies indexed in Pubmed, Medline, Scielo and Web of science to explain the molecular improvements following melatonin co-administration with special attention to oxidative stress, inflammation and apoptosis as key players of drug-induced nephrotoxicity.

RESULTS

A robust consensus among researchers of these studies suggested that melatonin efficiently eradicate the chain reaction of free radical production and induced the endogenous antioxidant enzymes which attenuate the lipid peroxidation of cellular membranes and subcellular oxidative stress in drug-induced nephrotoxicity. This agreement was further supported by the melatonin role in disintegration of inflammatory process through inhibition of principle pro-inflammatory or apoptotic cytokines such as TNF-α and NF-κB. These studies highlighted that alleviation of drug-induced renal toxicity is a function of melatonin potential to down regulate the cellular inflammatory and oxidative injury process and to stimulate the cellular repair or defensive mechanisms.

CONCLUSION

The comprehensive nephroprotection and safer profile suggests the melatonin to be a useful adjunct to improve the safety of nephrotoxic drugs.

Biomarkers of Drug-Induced Kidney Toxicity

Blood urea nitrogen and serum creatinine are imperfect markers of kidney function because they are influenced by many renal and nonrenal factors independent of kidney function. A biomarker that is released directly into the blood or urine by the kidney in response to injury may be a better early marker of drug-induced kidney toxicity than blood urea nitrogen and serum creatinine. Urine albumin and urine protein, as well as urinary markers kidney injury molecule-1 (KIM-1), β2-microglobulin (B2M), cystatin C, clusterin, and trefoil factor-3 (TFF-3) have been accepted by the Food and Drug Administration and European Medicines Agency as highly sensitive and specific urinary biomarkers to monitor drug-induced kidney injury in preclinical studies and on a case-by-case basis in clinical trials. Other biomarkers of drug-induced kidney toxicity that have been detected in the urine of rodents or patients include IL-18, neutrophil gelatinase-associated lipocalin, netrin-1, liver-type fatty acid-binding protein (L-FABP), urinary exosomes, and TIMP2 (insulin-like growth factor-binding protein 7)/IGFBP7 (insulin-like growth factor-binding protein 7), also known as NephroCheck, the first Food and Drug Administration-approved biomarker testing platform to detect acute kidney injury in patients. In the future, a combined use of functional and damage markers may advance the field of biomarkers of drug-induced kidney toxicity. Earlier detection of drug-induced kidney toxicity with a kidney-specific biomarker may result in the avoidance of nephrotoxic agents in clinical studies and may allow for earlier intervention to repair damaged kidneys.

[Ifosphamide nephrotoxicity]

Ifosfamide is a cytotoxic drug usually used in malignant sarcomas. The nephrotoxicity of this agent has been described essentially among children, revealed by renal failure and proximal tubulopathy. We recently conducted a retrospective multicentre study, describing 34 adult patients admitted for ifosfamide nephrotoxicity. More than 80% of them presented with renal failure, diagnosed up to 48 months after ifosfamide administration. A Fanconi syndrome with hypophosphoremia, hypokaliemia, glucosuria and low-molecular weight proteinuria, was present in two third of all cases. Median estimated glomerular filtration rate was 31mL/min 1 month and 38mL/min 3 months after ifosfamide infusion, versus 67mL/min at baseline. Renal biopsy, performed in 14 of these patients, showed acute tubular necrosis with vacuolization of proximal tubular epithelial cells with marked nuclear modifications, whereas electron microscopy revealed major changes of mitochondrial structure inside those cells, suggesting a tenofovir-like mechanism of nephrotoxicity. After a median follow-up of 31 months, ten patients out of 34 reached stage 5 chronic kidney disease, requiring dialysis in five cases. Poor renal prognosis was associated with concomitant cisplatin use (P=0.02) and with older age at presentation (P=0.04). In conclusion, ifosfamide nephrotoxicity is often severe and irreversible, leading to proximal tubulopathy and sometimes-severe chronic kidney failure, that can be immediate or delayed, sometimes diagnosed months after chemotherapy completion.

Renal toxicity and chemotherapy in children with cancer

The clinical use of antineoplastic drugs can be limited by different drug-induced toxicities. Of these, renal dysfunction may be one of the most troublesome in that it can be cumulative and in general is only partially reversible with the discontinuation of the treatment. Renal toxicity may be manifested as a reduction of the glomerular filtration rate, electrolyte imbalances, or acute renal failure. Careful assessment of renal function has to be performed taking into account that the impairment of renal function is initially silent and only later may be clinically dramatic. When clinically indicated, the reduction or, in cases of severe nephrotoxicity, the suspension of chemotherapy should be considered to avoid the progressive deterioration of the compromised glomerular and/or tubular function.

Diagnostic Accuracy of Tests for Polyuria in Lithium-Treated Patients

In lithium-treated patients, polyuria increases the risk of dehydration and lithium toxicity. If detected early, it is reversible. Despite its prevalence and associated morbidity in clinical practice, it remains underrecognized and therefore undertreated. The 24-hour urine collection is limited by its convenience and practicality. This study explores the diagnostic accuracy of alternative tests such as questionnaires on subjective polyuria, polydipsia, nocturia (dichotomous and ordinal responses), early morning urine sample osmolality (EMUO), and fluid intake record (FIR). This is a cross-sectional study of 179 lithium-treated patients attending a general adult and an old age psychiatry service. Participants completed the tests after completing an accurate 24-hour urine collection. The diagnostic accuracy of the individual tests was explored using the appropriate statistical techniques. Seventy-nine participants completed all of the tests. Polydipsia severity, EMUO, and FIR significantly differentiated the participants with polyuria (area under the receiver operating characteristic curve of 0.646, 0.760, and 0.846, respectively). Of the tests investigated, the FIR made the largest significant change in the probability that a patient experiences polyuria (<2000 mL/24 hours; interval likelihood ratio, 0.18 and >3500 mL/24 hours; interval likelihood ratio, 14). Symptomatic questioning, EMUO, and an FIR could be used in clinical practice to inform the prescriber of the probability that a lithium-treated patient is experiencing polyuria.

Survivorship

Significant therapeutic advances for soft tissue sarcomas allow increasing numbers of patients--adult and pediatric--to achieve long term survival. However, the harsh cytotoxic therapies are responsible for adverse physical and psychosocial effects that require long-term follow-up care, specific to survivorship issues. In the adult and pediatric patient population, guidelines for care developed by experts in comprehensive survivorship clinics are evolving to assist the practitioner while on-line supports bring information directly to the survivors.

Ifosfamide-induced Fanconi syndrome with diabetes insipidus

Ifosfamide-induced Fanconi syndrome is a rare complication that typically occurs in young patients due to a cumulative dose of ifosfamide > 40-60 g/m(2), a reduction in kidney mass, or concurrent cisplatin treatment. It is usually characterized by severe and fatal progression accompanied by type II proximal renal tubular dysfunction, as evidenced by glycosuria, proteinuria, electrolyte loss, and metabolic acidosis. Diabetes insipidus is also a rare complication of ifosfamide-induced renal disease. We herein describe a case involving a 61-year-old man who developed ifosfamide-induced Fanconi syndrome accompanied by diabetes insipidus only a few days after the first round of chemotherapy. He had no known risk factors. In addition, we briefly review the mechanisms and possible therapeutic options for this condition based on other cases in the literature. Patients who receive ifosfamide must be closely monitored for renal impairment to avoid this rare but fatal complication.

Protective effects of alpha lipoic acid versus N-acetylcysteine on ifosfamide-induced nephrotoxicity

Ifosfamide (IFO) is a highly effective chemotherapeutic agent for treating a variety of pediatric solid tumors. However, its use is limited due to its serious side effect on kidneys. The side-chain oxidation of IFO in renal tubular cells produces a reactive toxic metabolite that is believed to be responsible for its nephrotoxic effect. Therefore, this study was carried out to investigate the possible underlying mechanisms that may be involved in IFO-induced nephrotoxicity, including free radical generation and the possible role of alpha lipoic acid (ALA) versus N-acetylcysteine (NAC) in protection against this toxicity. Male albino rats were injected intraperitoneally with saline, IFO (50 mg/kg daily for 5 days), IFO + ALA (100 mg/kg daily for 8 days) and IFO + NAC (200 mg/kg daily for 8 days). Kidney malondialdehyde, nitric oxide and glutathione contents and serum biochemical parameters and histopathological analysis were determined. Both ALA and NAC markedly reduced the severity of renal dysfunction induced by IFO. NAC was more nephroprotective than ALA. This study suggests that oxidative stress is possibly involved in the IFO-induced nephrotoxicity in rats. The study also suggests the potential therapeutic role for ALA and NAC against IFO-induced nephrotoxicity.

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.

Osteomalacia as a late metabolic complication of Ifosfamide chemotherapy in young adults: illustrative cases and review of the literature

Purpose. Ifosfamide is a drug commonly used in the management of sarcomas and other solid tumours. One potential toxicity of its use is renal tubular damage, which can lead to skeletal abnormalities; rickets in children and osteomalacia in adults. We aimed to characterise this rare complication in adults. Patients. Three illustrative patient cases treated in our institution are presented. All were treated for sarcoma, and received varying doses of ifosfamide during their therapy. Methods. We performed a review of the literature on the renal tubular and skeletal complications of ifosfamide in adults. Papers were identified by searches of PubMed using the terms "osteomalacia," "nephrotoxicity," "Fanconi syndrome," "ifosfamide," and "chemotherapy" for articles published between 1970 and 2006. Additional papers were identified from review of references of relevant articles. Results. There are only four case reports of skeletal toxicity secondary to ifosfamide in adults; the majority of data refer to children. Risk factors for development of renal tubular dysfunction and osteodystrophy include platinum chemotherapy, increasing cumulative ifosfamide dose, and reduced nephron mass. The natural history of ifosfamide-induced renal damage is variable, dysfunction may not become apparent until some months after treatment, and may improve or worsen with time. Discussion. Ifosfamide-induced osteomalacia is seldom described in adults. Clinicians should be vigilant for its development, as timely intervention may minimise complications.

New clues for nephrotoxicity induced by ifosfamide: preferential renal uptake via the human organic cation transporter 2

Anticancer treatment with ifosfamide but not with its structural isomer cyclophosphamide is associated with development of renal Fanconi syndrome leading to diminished growth in children and bone problems in adults. Since both cytotoxics share the same principal metabolites, we investigated whether a specific renal uptake of ifosfamide is the basis for this differential effect. First we studied the interaction of these cytotoxics using cells transfected with organic anion or cation transporters and freshly isolated murine and human proximal tubules with appropriate tracers. Next we determined changes in membrane voltage in proximal tubular cells to understand their differentiated nephrotoxicity. Ifosfamide but not cyclophosphamide was significantly transported into cells expressing human organic cation transporter 2 (hOCT2) while both did not interact with organic anion transporters. This points toward a specific interaction of ifosfamide with hOCT2, which is the main OCT isoform in human kidney. In isolated human proximal tubules ifosfamide also interacted with organic cation transport. This interaction was also seen in isolated mouse proximal tubules; however, it was absent in tubules from OCT-deficient mice, illustrating the biological importance of this selective transport. Ifosfamide decreased the viability of cells expressing hOCT2, but not that of control cells. Coadministration of cimetidine, a known competitive substrate of hOCT2, completely prevented this ifosfamide-induced toxicity. Finally, ifosfamide but not cyclophosphamide depolarized proximal tubular cells. We propose that the nephrotoxicity of ifosfamide is due to its selective uptake by hOCT2 into renal proximal tubular cells, and that coadministration of cimetidine may be used to prevent ifosfamide-induced nephrotoxicity.

Ifosfamide nephrotoxicity in children: a mechanistic base for pharmacological prevention

The antineoplastic drug ifosfamide (IFO) in the treatment of solid tumors, particularly in children, is the cause of severe nephrotoxicity. Although it is a potent and effective chemotherapeutic agent, the associated nephrotoxicity has a serious impact on the health and the quality of life of exposed children. The toxic metabolite of IFO thought to be responsible for IFO-induced kidney damage is chloroacetaldehyde (CAA). Those suffering from nephrotoxicity typically develop tubular and glomerular toxicities, with the most severe form being Fanconi's syndrome. As the mode of toxicity of CAA seems to be primarily owing to oxidative stress, the use of antioxidants as a protective measure for the kidneys is a promising strategy. In this review, we highlight recent research that supports the local renal production of CAA as the proximate cause of IFO-induced nephrotoxicity with age as an important risk factor, those under the age of three being the most vulnerable. Most importantly, we focus on the potential advantages of the antioxidant N-acetylcysteine owing to both its antioxidant properties and its current use clinically in pediatrics.

Renal disease in patients with cancer

Kidney disease is very common in patients with cancer. Nephrologists are vital members of the multidisciplinary care team for these patients. Given the high prevalence of comorbidities in patients treated for active malignancy, it is not surprising that these individuals frequently develop renal diseases that are common among other hospitalized patients, such as those arising from sepsis, hypotension or use of nephrotoxic agents (e.g. radiocontrast or antimicrobial agents). The role of the nephrologist in these cases differs little with respect to the presence or absence of cancer. On the other hand, there are several renal syndromes that are unique to patients with cancer, being caused either by the cancer itself or by its treatment. These syndromes are reviewed here. In addition, patients who are receiving chemotherapy often require dialysis for either acute or chronic kidney disease. Unfortunately, there is very little information on the clearance characteristics of most chemotherapeutic agents. In cancer patients with renal disease, both the timing of administration and the dose-adjustment of chemotherapy must rely on clinical experience and close clinical observation.

Ontogeny of drug elimination by the human kidney

Renal clearance is an important route of drug elimination. While during the neonatal period there is minimal glomerular filtration and active tubular secretion of drugs, there is a well-described rapid development in these processes in the post-neonatal period. A less appreciated fact is that during toddlerhood, there is an "overshoot" of the glomerular filtration rate (GFR) well above the levels encountered in older children and adults, and there is an early achievement of adult levels in active drug secretion, which stays at a plateau throughout childhood and adulthood with an "overshoot" in toddlers due to specific transport mechanisms. This phenomenon leads to dose requirements for renally excreted drugs in this age group being, on a per-kilogram basis, much larger than in adults. This review discusses the mechanisms related to renal ontogeny in drug handling.

A Phase I Study of Prolonged Ambulatory Infusion of Ifosfamide with Oral Mesna

BACKGROUND

Oral mesna allows investigation of ifosfamide as a prolonged ambulatory infusion for dose-intense out-patient use.

METHODS

Cohorts of 3 patients received escalating doses of ifosfamide from 200 to 1,000 mg/m2/day as continuous ambulatory infusion with oral mesna at 30% of the ifosfamide dose every 6 h commencing 2 h prior to ifosfamide infusion as uroprotection on a 14-day schedule with cycles repeated every 28 days.

RESULTS

Fifteen patients received a median of three cycles. Dose-limiting toxicities with cycle 1 were lethargy and hepatotoxicity at 1,000 mg/m2/14 days. Transient transaminase elevation was seen at all dose levels. The other grade 3 toxicities were single episodes of anaemia, granulocytopenia, nausea and hypotension. The best response was stable disease in a patient with thyroid cancer.

CONCLUSION

Ambulatory infusion of 600 mg/m2 ifosfamide with 180 mg/m2 oral mesna was considered suitable for phase II trials and delivers dose-intense out-patient therapy without urotoxicity.

Renal impairment and hypertension in brain tumor patients treated in childhood are mainly associated with cisplatin treatment

BACKGROUND

This study was designed to evaluate the renal consequences of the treatment of brain tumor patients diagnosed in childhood.

PROCEDURE

One hundred four primary brain tumor patients diagnosed before 17 years of age from 1983 to 1997 had been treated in Tampere University Hospital, Finland. Of the 80 survivors 52 (65.0%) were examined at a median age of 14.4 years (range 3.8-28.7) and median 6.0 years (range 1.2-14.8) after the last treatment. The main outcome measures were blood pressure (BP), renal function, and calcium metabolism.

RESULTS

Eight patients (15.4%) were hypertensive. Elevated BP was observed especially after exposure both to cisplatin and cranial irradiation. Spinal radiation did not increase the risk of elevated BP. Other adverse effects were observed only in patients treated with cisplatin. Five out of 14 patients treated with cisplatin evinced renal glomerular dysfunction (GFR < 87 mL/min/1.73 m2) immediately after treatment. They had a high cumulative dose of cisplatin (490-880 mg/m2). Recovery from renal glomerular dysfunction was observed in one patient. Nine of 14 patients were hypomagnesemic at the close of cisplatin treatment. Thereafter the magnesium level decreased in 10/14 cases (P = 0.006). During the study 10/14 were hypomagnesemic (P < 0.001); one evinced severe symptomatic hypomagnesemia. Low plasma phosphate (P = 0.016) and potassium levels (P = 0.026), tubular proteinuria (P = 0.055), metabolic alkalosis (P = 0.071), and hyperuricemia (P = 0.114) were also more common in patients on cisplatin treatment.

CONCLUSIONS

Elevated BP is common among brain tumor patients treated in childhood. After cisplatin treatment renal glomerular dysfunction appears mostly to be permanent. Persistent and even progressive changes in renal tubular function are seen.

Renal ontogeny of ifosfamide nephrotoxicity

Ifosfamide-induced nephrotoxicity adversely affects the health and well-being of children with cancer. We have recently shown age-dependent nephrotoxicity induced by ifosfamide, with younger children (<3 years) substantially more vulnerable. The mechanisms leading to this age-related ifosfamide-induced renal damage have not been identified. Underlying this work is the hypothesis that renal ontogeny is involved in the expression and activity of the cytochrome P450 (CYP) enzymes responsible for IF metabolism to the nephrotoxic chloroacetaldehyde. We evaluated renal CYP3A and 2B22 activity in pigs between the ages of 1 day and adulthood, as well as the metabolism of ifosfamide by renal microsomes to 2- and 3-dechloroethylifosfamide (2-DCEIF and 3-DCEIF, respectively). Kidney CYP3A messenger RNA expression peaked 15 to 60 days (0.7-76 +/- 0.19 CYP3A/actin ratio; P < 0.001). Subsequently, this level decreased to adult values (0.54 - 0.03 CYP3A/actin ratio; P = 0.04). Similarly, we detected an increase in the ifosfamide-metabolism rate between young (18 +/- 2 pmol/mg protein/min) and adult (12.2 +/- 0.17 pmol/mg protein/min) animals (P = 0.002). Ours is the first documentation of ontogeny of renal CYP3A and of renal ifosfamide metabolism. These data suggest that age-dependent ifosfamide nephrotoxicity is, at least in part, due to ontogeny in the production chloroacetaldehyde.

Acute renal failure in cancer patients

Acute renal failure (ARF) is defined as a sudden decrease in glomerular filtration rate leading to an acute rise in blood urea nitrogen and serum creatinine levels. It is a serious complication of cancer and constitutes a major source of morbidity and mortality. Current data suggest that ARF has the potential to substantially jeopardize the chances of cancer patients receiving optimal treatment and a potential cure. The pathways leading to ARF in cancer patients are common to the development of ARF in other conditions. However, ARF may also develop due to aetiologies arising from cancer treatment or the disease itself, including: nephrotoxic chemotherapy agents, post-renal obstruction, compression and infiltration by malignancy, tumour lysis syndrome, uric acid, sepsis and contrast agent nephropathy. This review provides a comprehensive overview of the causes of ARF in patients with cancer and guidance on how to prevent and treat this condition. Ultimately, the key to managing ARF in cancer patients is to ensure that a multidisciplinary approach provides adequate assessment, appropriate preventative measures and early intervention.

Influence of age upon Ifosfamide-induced nephrotoxicity

BACKGROUND

Ifosfamide-induced nephrotoxicity is well recognized in children, although it has also been reported in adults. Whether ifosfamide nephrotoxicity is more common in children than in adults is not known.

PROCEDURE

Medical records of adults and children diagnosed with sarcoma whom received ifosfamide with a cumulative dose >20 g/m(2) were evaluated. Twenty-five children (</=18-years of age) and 28 adults were identified.

RESULTS

National Cancer Institute Common Toxicity Criteria grade 3-4 ifosfamide-induced nephrotoxicity was present in 24 and 17% of children and adults, respectively (P = 0.58). Cumulative ifosfamide doses were similar between the two populations, with the median (range) of 70.2 g/m(2) (22.4-72) for children and 59 g/m(2) (20.8-146) for adults (P = 0.25). Logistic regression analysis indicated that neither age or cumulative ifosfamide dose were associated with grade 3-4 ifosfamide-induced nephrotoxicity (P = 0.36).

CONCLUSIONS

Children and adults receiving >20 g/m(2) of ifosfamide have similar susceptibility to ifosfamide-induced nephrotoxicity. Factors other than age and cumulative dose should be considered for understanding the inter-individual variation in nephrotoxicity.

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.

Risk factors for nephrotoxicity after ifosfamide treatment in children: a UKCCSG Late Effects Group study. United Kingdom Children's Cancer Study Group

The aim of this multicentre study was to document the nephrotoxicity associated with ifosfamide and evaluate risk factors in 148 children and young people with sarcomas who underwent investigation of renal function on one occasion each, at a median of 6 (range 1-47) months after completion of ifosfamide (median dose 62.0 (range 6.1-165.0) g/m2). Investigations included glomerular filtration rate (GFR), serum bicarbonate (HCO3) and phosphate (PO4), and renal tubular threshold for phosphate (Tmp/GFR). A clinically relevant nephrotoxicity score' was derived. GFR was < 90 ml/min/1.73 m2 in 61 of 123 evaluable patients, Tmp/GFR < 0.9-1.1 mmol/l (age-dependent) in 45/103, serum PO4 < 0.9-1.mmol/l (age-dependent) in 28/135, and serum HCO3 < 20 (< 18 in infants) mmol/l in 22/95. Of 76 fully evaluable patients: 50% had mild, 20% moderate and 8% severe nephrotoxicity. Higher total ifosfamide dose correlated significantly with greater glomerular and tubular toxicity (P < 0.01); other risk factors, including age at treatment, demonstrated no consistent significant independent effect. Chronic ifosfamide-related glomerular and proximal tubular toxicity were common in this large comprehensive study. Restriction of total ifosfamide dose to < 84 g/m2 will reduce the frequency of, but not abolish, clinically significant nephrotoxicity, whilst doses > 119 g/m2 are associated with a very high risk of severe toxicity.

Cardiotoxicity of chemotherapeutic agents: incidence, treatment and prevention

Cytostatic antibiotics of the anthracycline class are the best known of the chemotherapeutic agents that cause cardiotoxicity. Alkylating agents such as cyclophosphamide, ifosfamide, cisplatin, carmustine, busulfan, chlormethine and mitomycin have also been associated with cardiotoxicity. Other agents that may induce a cardiac event include paclitaxel, etoposide, teniposide, the vinca alkaloids, fluorouracil, cytarabine, amsacrine, cladribine, asparaginase, tretinoin and pentostatin. Cardiotoxicity is rare with some agents, but may occur in >20% of patients treated with doxorubicin, daunorubicin or fluorouracil. Cardiac events may include mild blood pressure changes, thrombosis, electrocardiographic changes, arrhythmias, myocarditis, pericarditis, myocardial infarction, cardiomyopathy, cardiac failure (left ventricular failure) and congestive heart failure. These may occur during or shortly after treatment, within days or weeks after treatment, or may not be apparent until months, and sometimes years, after completion of chemotherapy. A number of risk factors may predispose a patient to cardiotoxicity. These are: cumulative dose (anthracyclines, mitomycin); total dose administered during a day or a course (cyclophosphamide, ifosfamide, carmustine, fluorouracil, cytarabine); rate of administration (anthracyclines, fluorouracil); schedule of administration (anthracyclines); mediastinal radiation; age; female gender; concurrent administration of cardiotoxic agents; prior anthracycline chemotherapy; history of or pre-existing cardiovascular disorders; and electrolyte imbalances such as hypokalaemia and hypomagnesaemia. The potential for cardiotoxicity should be recognised before therapy is initiated. Patients should be screened for risk factors, and an attempt to modify them should be made. Monitoring for cardiac events and their treatment will usually depend on the signs and symptoms anticipated and exhibited. Patients may be asymptomatic, with the only manifestation being electrocardiographic changes. Continuous cardiac monitoring, baseline and regular electrocardiographic and echocardiographic studies, radionuclide angiography and measurement of serum electrolytes and cardiac enzymes may be considered in patients with risk factors or those with a history of cardiotoxicity. Treatment of most cardiac events induced by chemotherapy is symptomatic. Agents that can be used prophylactically are few, although dexrazoxane, a cardioprotective agent specific for anthracycline chemotherapy, has been approved by the US Food and Drug Administration. Cardiotoxicity can be prevented by screening and modifying risk factors, aggressively monitoring for signs and symptoms as chemotherapy is administered, and continuing follow-up after completion of a course or the entire treatment. Prompt measures such as discontinuation or modification of chemotherapy or use of appropriate drug therapy should be initiated on the basis of changes in monitoring parameters before the patient exhibits signs and symptoms of cardiotoxicity.

Osteoporosis due to cancer treatment: pathogenesis and management

Many therapeutic regimens in cancer treatment carry the risk of causing or favoring the development of osteoporosis. Therapies in which hypogonadism may occur are most relevant in this respect. Prompt hormone replacement therapy is indicated in these patients. In patients in whom this is undesirable because of a hormone-dependent tumor, the risk of osteoporosis should be assessed by means of osteodensitometry, and prophylactic or therapeutic measures should be instituted if necessary. Early intervention improves outcome because osteoporosis therapy is most effective in preventing deterioration of bone mass. There remains much uncertainty in assessing the risk of combination chemotherapy with regard to the development of osteoporosis. Negative effects on the skeleton have, however, been demonstrated for individual drugs, such as methotrexate and ifosfamide. Negative effects of the tumor itself on bone metabolism may aggravate the degree of osteoporosis. Detailed data and long-term experience to assess the risk are urgently needed in this area and constitute an important research topic for the coming years and decades. This review discusses the most prevalent mechanisms of osteoporosis caused by cancer treatment and outlines therapeutic strategies for the prevention and treatment of therapy-induced bone loss.

Comparative renal tubular toxicity of chemotherapy regimens including ifosfamide in patients with newly diagnosed sarcomas

PURPOSE

The aim of this study was to assess renal tubular toxicity (RTT) of ifosfamide-containing regimens (ICR) in patients with newly diagnosed sarcomas at St. Jude Children's Research Hospital.

METHODS

The authors reviewed the records of 199 patients receiving ICR at St. Jude between June 1986 and December 31, 1994 for evidence of RTT. Their median age was 13.3 years (range 1.2-24.8); 150 patients were white and 112 were male patients. Diagnoses included osteosarcoma (n = 82), Ewing sarcoma (n = 82), rhabdomyosarcoma (n = 28), and a group of other tumors (n = 7).

RESULTS

The authors estimated the proportion of patients with severe RTT during the first five cycles of ICR and within 1 year after therapy for three groups of patients receiving ifosfamide (IFOS, n = 110), ifosfamide/cisplatin (IFOS/CDDP, n = 51), and ifosfamide/carboplatin (IFOS/CARBO, n = 38). The IFOS/CDDP patients received three cycles of IFOS before receiving CDDP and received only 200 mg/m2 by cycle 5, whereas the IFOS/CARBO patients received both agents simultaneously. The authors compared the probability of severe RTT among treatment groups using a generalized linear model for the first five cycles of ICR, as well as the probability of severe RTT within 1 year after therapy among treatment groups for patients receiving all prescribed IFOS using an exact chi-square test with pairwise comparisons when the three-way P value was less than 0.10. The proportion of patients with severe RTT during the first three cycles of ICR was significantly greater in the IFOS/CARBO group than in the other two. Although the proportion of patients with severe RTT in the IFOS/CDDP group increased during cycles 4/5, the proportion of patients with severe RTT remained significantly greater in the IFOS/ CARBO group. Within 1 year after therapy, the proportion of patients with severe RTT differed among the three groups, and pairwise comparisons revealed a significant difference between the IFOS and the IFOS/CDDP group. Severe RTT developed in four IFOS/CDDP patients more than 1 year after therapy, suggesting a long-term effect of CDDP on tubular function.

CONCLUSIONS

Chemotherapy regimens including IFOS/ CARBO produce severe acute RTT more frequently than regimens including IFOS or IFOS/CDDP. Patients receiving IFOS/ CDDP appear at risk for delayed RTT. Long-term follow-up of these patients is essential to assess whether the number of patients receiving IFOS/CDDP with severe RTT continues to increase over time and to evaluate the long-term significance of these abnormalities.

Development of ifosfamide-induced nephrotoxicity: prospective follow-up in 75 patients

PURPOSE

This study was performed to describe prospectively the development and prognosis of severe ifosfamide-induced nephrotoxicity and to define the period of recommended renal follow-up after ifosfamide chemotherapy.

PATIENTS AND METHODS

Renal function was followed in 75 patients after cessation of chemotherapy starting within the first year off therapy; median follow-up time was 31 months. The glomerular filtration rate was estimated by using the Schwartz formula. Proximal tubular transport capacities were evaluated for amino acids, phosphate, sodium, and glucose. In addition, serum bicarbonate level and alkaline phosphatase were measured.

RESULTS

Five patients developed renal Fanconi syndrome during follow-up, and another seven patients developed a generalized subclinical tubulopathy. The latter condition always preceded Fanconi syndrome. Severe impairment of amino acid and phosphate reabsorption was seen in 28% and 17.3% of patients, respectively. Reductions in amino acid reabsorption preceded impairment of phosphate reabsorption. In patients with early impairment of phosphate reabsorption, renal prognosis was poor, whereas normal or only mildly impaired amino acid handling virtually excluded progressive tubular damage.

CONCLUSIONS

Ifosfamide-induced renal tubular damage is a potentially progressive disease. Along with measurement of phosphate reabsorption, additional assessment of tubular amino acid handling is suggested, because it allows early discrimination of poor from favorable renal outcomes.

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.

Nephrotoxicity of high-dose ifosfamide/carboplatin/etoposide in adults undergoing autologous stem cell transplantation

The objective of this study was to evaluate nephrotoxicity in adult patients treated with high-dose ifosfamide, carboplatin, and etoposide followed by autologous stem cell transplantation. We conducted a retrospective analysis of clinical and laboratory data from 131 patients with various malignancies who received treatment with escalating doses of ifosfamide, carboplatin, and etoposide followed by autologous stem cell transplantation as part of a phase I/II therapeutic trial. Abnormalities in glomerular filtration were evaluated by measuring peak creatinine levels and tubular dysfunction by the lowest recorded serum levels of potassium, magnesium, and bicarbonate, at different time periods after administration of ifosfamide, carboplatin, and etoposide, and after autologous stem cell transplantation. For the entire group of 131 patients, peak creatinine levels were > 1.5 mg/dL but < 3.0 mg/dL in 37% and levels were > 3.0 mg/dL in 11% at some time during their hospital stay. At the time of discharge, creatinine levels were 1.6 mg/dL to 3.0 mg/dL in 25% of patients and were > 3 mg/dL in 5%. Immediately after high-dose therapy, peak creatinine levels were significantly higher in patients receiving higher doses of ifosfamide compared to those receiving lower doses (P < 0.00001) and those receiving intermediate doses (P < 0.005). There was a dramatic decrease in serum bicarbonate, potassium, and magnesium levels immediately after chemotherapy, and they remained significantly decreased throughout the patient's hospital stay, despite massive replacement efforts (P ranging between < 0.008 and < 0.001). This is the largest adult population study documenting the incidence and severity of ifosfamide/carboplatin/etoposide-associated acute nephrotoxicity. Renal dysfunction was dose related and reversible in the majority of patients.

[Renal function after nephrectomy for Wilms' tumor]

BACKGROUND

Most children with Wilms tumour recover after nephrectomy, chemotherapy and sometimes radiotherapy. It is therefore important to assess their long-term renal function.

POPULATION AND METHODS

Thirty-three patients with Wilms tumour experienced unilateral nephrectomy between 1986 and 1993: three were excluded; 23 were staged as grade I, one at grade II, two at grade III and four at grade IV. They were treated with SIOP 6 and SIOP 9 protocols. The results were compared to five controls who underwent unilateral nephrectomy including three for renal trauma. The glomerular filtration rate (GFR) was measured by inulin clearance and the renal plasma flow (RPF) by para-amino-hippuric acid clearance.

RESULTS

The mean age at nephrectomy was 3.4 +/- 2.5 years (median: 3, range: 0.2-10.6) and the duration of follow-up was 4.6 +/- 3.1 years (median: 4.5, range: 1-8.5), the GFR was 93 +/- 13 mL/min/1.73 m2 (median: 93, range: 73-130), the RPF was 441 +/- 85 mL/min/1.73 m2 (median: 453, range: 236-650) and the filtrated fraction (FF) was 0.21 +/- 0.03 (median: 0.20, range: 0.18-0.31). The difference in renal function between patients and controls was not significant (GRF: 86 +/- 12 mL/min/1.73 m2, RPF: 486 +/- 185 mL/min/1.73 m2, FF: 0.22 +/- 0.03). The electrolyte reabsorption rate was normal and none of the patients suffered from arterial hypertension. Fourteen children had urinary albumin: creatinine ratio > 2 g/mol. When comparing patients according to the duration of follow-up after nephrectomy (< 4 years vs > 4 years), the renal function was not statistically different. The age at nephrectomy (< 2 years vs > 2 years) did not increase the risk of renal impairment.

CONCLUSION

Children with Wilms tumour who were treated with nephrectomy and non-nephrotoxic drugs (actinomycin, vincristine, epiadriamycin) have a good long-term renal outcome. It is speculated that systematic renal investigation should be limited to those children with increased microalbuminuria and/or elevated blood pressure.

Renal function after conditioning therapy for bone marrow transplantation in childhood

The knowledge of renal function in the course of BMT is poor. We prospectively investigated glomerular and tubular function in 42 children who underwent BMT because of malignancy. Seventeen children were transplanted autologously. Investigations were performed before and immediately after the conditioning regimen. Inulin and creatinine clearance, albuminuria, urine excretion of alpha 1-microglobulin, beta-N-acetylglucosaminidase, alanine-aminopeptidase, intestinal alkaline phosphatase, and Tamm-Horsfall-Protein as well as sodium- and phosphatreabsorption were measured. The patients were classified regarding use of total body irradiation (tTBI) in the conditioning regimen. BEFORE CR: Glomerular filtration rate (GFR) was not influenced by the underlying diagnosis or previous treatment. Mean GFR was elevated compared with the reference group. Microalbuminuria was elevated in 15% of patients, and mean levels were higher than in the reference group. Proximal tubular dysfunction was indicated by an elevated excretion of alpha 1-MG in 54%, of beta-NAG in 66%, of AAP in 40%, and of IAP in 47%. Fractional sodium excretion was abnormal in 21%, phosphate reabsorption in 5% and THP-excretion in 7% of the patients. AFTER CR: Creatinine clearance was not affected by CR. After CR alpha 1-MG, beta-NAG, FENa, AAP, and IAP were increased compared with values before CR. TP/Clcr was decreased. Excretion of THP was not altered by CR. In patients without fTBI there was a greater increase in alpha 1-MG excretion and decrease in phosphate reabsorption after CR compared with patients conditioned with fTBI. We conclude that significant proximal tubular dysfunction is present in about 50-60% of patients before and in nearly all alter CR. Distal tubular function was less severely affected. Severity of nephrotoxicity after CR did not correlate with pre-existing abnormalities.

Late reversibility of chronic ifosfamide-associated nephrotoxicity in a child

Although reversibility of acute ifosfamide-induced nephrotoxicity is well documented, there is a paucity of data concerning the long-term outcome of chronic renal toxicity, and full recovery from established damage has not been reported. A 4-year-old boy presented with hypophosphatemic rickets 9 months after completion of combination chemotherapy (including ifosfamide) for prostatic rhabdomyosarcoma. Further investigation confirmed glomerular and generalised tubular dysfunction with a Fanconi syndrome. However, serial investigation over the next 4 years revealed complete and sustained recovery of this chronic nephrotoxicity.

In vivo detection of ifosfamide by 31P-MRS in rat tumours: increased uptake and cytotoxicity induced by carbogen breathing in GH3 prolactinomas

The direct detection and monitoring of anti-cancer drugs in vivo by magnetic resonance spectroscopy (MRS) may lead to improved anti-cancer strategies. 31P-MRS has been used to detect and quantify ifosfamide (IF) in vivo in GH3 prolactinomas and N-methyl-N-nitrosourea (MNU)-induced mammary tumours in rats. The average concentration of IF in the GH3 prolactinoma over the first 2 h following a dose of 250 mg kg-1 i.v. was calculated to be 0.42 micromol g-1 wet weight, with a half-life of elimination (t1/2) of 2-4 h. Carbogen (95% oxygen/5% carbon dioxide) breathing increased the amount of IF taken up by the GH3 prolactinoma by 50% (P<0.01) to 0.68 micromol g-1 wet weight, although t1/2 elimination rates were unchanged. IF was also detected in the liver in vivo, with a t1/2 of about 1 h. Carbogen breathing did not affect the maximum peak area (Cmax) or the t1/2 in the liver. Most importantly, the carbogen-induced increase in IF uptake by the tumour caused significant growth delay at all time points in the GH3 tumour growth between day 5 and day 12 (P< 0.01) compared with IF alone. These findings show that carbogen breathing has potential for increasing the efficacy of anti-cancer drugs. Isolated GH3 cells were sensitive to the parent drug (IF) in vitro (IC50 = 1.3 +/- 0.2 mM) suggesting that the GH3 cells may be either expressing P450 enzymes or are sensitive to the parent drug per se.