Comparative study of the pharmacokinetics and toxicity of high-dose epirubicin with or without dexrazoxane in patients with advanced malignancy

Dexrazoxane

Anthracyclines are a fundamental part of many childhood cancer therapy regimens; however, the discovery of anthracycline-induced cardiotoxicity has raised concern and led to dose limitation. The cardiotoxicity of anthracyclines has resulted in an increased demand for cardioprotectants. Dexrazoxane is the only cardioprotectant that has proven efficacy in reducing cardiotoxic effects when given prior to the administration of anthracyclines. Currently, it is still considered an “off-label” use due to a paucity of data in the literature on dexrazoxane administration in children. Nevertheless, through evaluation of the available data, dexrazoxane is observed to be safe, tolerable, and efficacious in mitigating the cardiotoxic effects of anthracycline in children, without jeopardizing its antineoplastic activity or increasing the risk of developing secondary malignant neoplasms.

Oxidative stress, redox signaling, and metal chelation in anthracycline cardiotoxicity and pharmacological cardioprotection

SIGNIFICANCE

Anthracyclines (doxorubicin, daunorubicin, or epirubicin) rank among the most effective anticancer drugs, but their clinical usefulness is hampered by the risk of cardiotoxicity. The most feared are the chronic forms of cardiotoxicity, characterized by irreversible cardiac damage and congestive heart failure. Although the pathogenesis of anthracycline cardiotoxicity seems to be complex, the pivotal role has been traditionally attributed to the iron-mediated formation of reactive oxygen species (ROS). In clinics, the bisdioxopiperazine agent dexrazoxane (ICRF-187) reduces the risk of anthracycline cardiotoxicity without a significant effect on response to chemotherapy. The prevailing concept describes dexrazoxane as a prodrug undergoing bioactivation to an iron-chelating agent ADR-925, which may inhibit anthracycline-induced ROS formation and oxidative damage to cardiomyocytes.

RECENT ADVANCES

A considerable body of evidence points to mitochondria as the key targets for anthracycline cardiotoxicity, and therefore it could be also crucial for effective cardioprotection. Numerous antioxidants and several iron chelators have been tested in vitro and in vivo with variable outcomes. None of these compounds have matched or even surpassed the effectiveness of dexrazoxane in chronic anthracycline cardiotoxicity settings, despite being stronger chelators and/or antioxidants.

CRITICAL ISSUES

The interpretation of many findings is complicated by the heterogeneity of experimental models and frequent employment of acute high-dose treatments with limited translatability to clinical practice.

FUTURE DIRECTIONS

Dexrazoxane may be the key to the enigma of anthracycline cardiotoxicity, and therefore it warrants further investigation, including the search for alternative/complementary modes of cardioprotective action beyond simple iron chelation.

Dexrazoxane shows cytoprotective effects in zoledronic acid-treated human cells in vitro and in the rabbit tibia model in vivo

INTRODUCTION

Bisphosphonates are important and effective drugs in oncology and osteoporosis therapy. They accumulate in the bone matrix becoming released and active by bone resorption. This leads to effective inhibition of tumor cells and bone degradation. A side effect of bisphosphonates similar to other drugs like denosumab is osteonecrosis of the jaws (ONJ). This problem mostly occurs after tooth extraction. We studied the cytoprotectant dexrazoxane known from anthracycline chemotherapy for cytoprotection in nitrogen-containing bisphosphonate treated cells and in the rabbit tibia model to evaluate a possible value in ONJ management.

MATERIALS & METHODS

Human osteoblasts (HOB) P2 cells and Human ginigiva fibroblasts (HGF) P2 cells were treated with zoledronic acid (50 μmol/L) and the cytoprotectant dexrazoxane (600 μmol/L). Analysis included cell viability testing with MTT assay and morphology analysis using CellTracker™ Green CMFDA. A biomaterial carrier (Bio-Oss Collagen) was implanted in the rabbit tibia of 6 female chinchilla bastard rabbits on both sides with drill hole defects (d: 3.2mm). Implants were loaded with 25 nmol zoledronic acid, with and without 300 nmol dexrazoxane and unloaded in a control group. Analysis included histological examination of undecalcified samples with toloudine blue staining after 10 days.

RESULTS

In vitro experiments showed a significantly higher MTT activity in cells treated with zoledronic acid together with dexrazoxane compared to the same cells treated with the bisphosphonate alone in t-test (HOB: p=0.0003; HGF: p below 0.0001) and one-way ANOVA. Cell morphology changes were consistent with these results. In vivo results showed newly formed bone trabeculae directly growing towards the implanted hydroxylapatite particles and cortical bone interface resorption activities in the control and the experimental group only.

CONCLUSION

The study suggests a possible value of this patented technology for ONJ therapy and prevention with local or systemic application.

Cardioprotective Effects of Subcutaneous Ebselen against Daunorubicin-Induced Cardiomyopathy in Rats

Daunorubicin is an anthracycline antitumour agent that can cause severe cardiomyopathy leading to a frequently fatal congestive heart failure. Although the exact molecular mechanisms of cardiotoxicity are not well established, oxidative mechanisms involving daunorubicin-induced superoxide anion production have been proposed. In the present study, we showed that ebselen a seleno-organic compound exhibiting glutathione peroxidase-like and antioxidant activities, significantly ameliorated daunorubicin-induced cardiomyopathy. Subcutaneous administration of ebselen to daunorubicin-treated rats showed significant improvement in serum cardiac indices including creatine kinase isoenzyme and lactate dehydrogenase as well as serum glutathione (GSH) peroxidase. Moreover, myocardium of daunorubicin/ebselen-treated rats showed significant improvement in daunorubicin-induced depletion of GSH peroxidase activity and reduced glutathione content, in addition to attenuation of daunorubicin-induced increase in cardiac malondialdehyde production and total nitrate/nitrite concentration levels. These results were confirmed by histopathological examination of ventricles of daunorubicin/ebselen-treated rats that revealed significant improvement of the characteristic cardiomyopathic changes induced by daunorubicin treatment. Interestingly, control rats treated with ebselen showed significant elevation in serum lactate dehydrogenase activity, cardiac malondialdehyde production and total nitrate/nitrite concentration levels compared with the untreated control animals. In conclusion, ebselen treatment significantly alleviates daunorubicin-induced cardiomyopathy.

Effect of epirubicin-based chemotherapy and dexrazoxane supplementation on QT dispersion in non-Hodgkin lymphoma patients

BACKGROUND AND OBJECTIVE

Aim of the present study was to assess the effect of epirubicin-based chemotherapy on QT interval dispersion in patients with aggressive non-Hodgkin lymphoma (NHL), and the effect of dexrazoxane supplementation. Prolongation of QT dispersion may not only represent a sensitive tool in identifying the first sign of anthracycline-induced cardiotoxicity, but it may serve also in identifying patients who are at risk of arrhythmic events.

METHODS

Twenty untreated patients, <or=60 years of age with newly-diagnosed aggressive NHL, eligible for a treatment with epirubicin-based chemotherapy were selected for the study. The patients were randomly allocated in two subgroups (N=10) to receive or not dexrazoxane hydrochloride (400 mg/m(2)) after epirubicin infusion. The patients underwent 12-lead electrocardiogram (ECG) before and after epirubicin infusion and after dexrazoxane supplementation. QT dispersion was defined as the difference between the maximum and the minimum QT interval occurring in any of the 12 ECG leads, corrected (QTc) for heart rate.

RESULTS

All the 20 patients showed increased QT dispersion (44.3 +/- 8.4 vs. 68.4+/-11.4 ms, P<0.001) and QTc dispersion (46.2 +/- 6.2 vs. 72.2 +/- 8.4, P<0.001) after chemotherapy infusion. The 10 patients who underwent supplementation with dexrazoxane exhibited a significant reduction of QT dispersion (67.4 +/- 8.1 vs. 49.5 +/- 4.2 ms, P<0.001) and QTc dispersion (71.2 +/- .7 vs. 51.4 +/- 4.3 ms, P<0.001), while the 10 patients not supplemented with dexrazoxane did not (QT dispersion: 69.3 +/- 7.6 vs. 64.2 +/- 6.9 ms; QTc dispersion: 72.8 +/- 8.1 vs. 67.3 +/- 7.2 ms, ns).

CONCLUSIONS

Epirubicin-based chemotherapy causes an early increase of the QT and QTc dispersion, which is attenuated by dexrazoxane supplementation. Therefore, dexrazoxane can reduce the arrhythmic risk in patients treated with epirubicin.

Dexrazoxane : a review of its use for cardioprotection during anthracycline chemotherapy

Dexrazoxane (Cardioxane, Zinecard, a cyclic derivative of edetic acid, is a site-specific cardioprotective agent that effectively protects against anthracycline-induced cardiac toxicity. Dexrazoxane is approved in the US and some European countries for cardioprotection in women with advanced and/or metastatic breast cancer receiving doxorubicin; in other countries dexrazoxane is approved for use in a wider range of patients with advanced cancer receiving anthracyclines. As shown in clinical trials, intravenous dexrazoxane significantly reduces the incidence of anthracycline-induced congestive heart failure (CHF) and adverse cardiac events in women with advanced breast cancer or adults with soft tissue sarcomas or small-cell lung cancer, regardless of whether the drug is given before the first dose of anthracycline or the administration is delayed until cumulative doxorubicin dose is > or =300 mg/m2. The drug also appears to offer cardioprotection irrespective of pre-existing cardiac risk factors. Importantly, the antitumour efficacy of anthracyclines is unlikely to be altered by dexrazoxane use, although the drug has not been shown to improve progression-free and overall patient survival. At present, the cardioprotective efficacy of dexrazoxane in patients with childhood malignancies is supported by limited data. The drug is generally well tolerated and has a tolerability profile similar to that of placebo in cancer patients undergoing anthracycline-based chemotherapy, with the exception of a higher incidence of severe leukopenia (78% vs 68%; p < 0.01). Dexrazoxane is the only cardioprotective agent with proven efficacy in cancer patients receiving anthracycline chemotherapy and is a valuable option for the prevention of cardiotoxicity in this patient population.

Cardiotoxicity of cytotoxic drugs

Cardiotoxicity is a well-known side effect of several cytotoxic drugs, especially of the anthracyclines and can lead to long term morbidity. The mechanism of anthracycline induced cardiotoxicity seems to involve the formation of free radicals leading to oxidative stress. This may cause apoptosis of cardiac cells or immunologic reactions. However, alternative mechanisms may play a role in anthracycline induced cardiotoxicity. Cardiac protection can be achieved by limitation of the cumulative dose. Furthermore, addition of the antioxidant and iron chelator dexrazoxane to anthracycline therapy has shown to be effective in lowering the incidence of anthracycline induced cardiotoxicity. Other cytotoxic drugs such as 5-fluorouracil, cyclophosphamide and the taxoids are associated with cardiotoxicity as well, although little is known about the possible mechanisms. Recently, it appeared that some novel cytotoxic drugs such as trastuzumab and cyclopentenyl cytosine also show cardiotoxic side effects.

Minimising the long-term adverse effects of childhood leukaemia therapy

Malignancies in childhood occur with an incidence of 13-14 per 100,000 children under the age of 15 years. Acute lymphoblastic leukaemia with an incidence of 29% is the most common paediatric malignancy, whereas acute myeloid leukaemias account for about 5%. The treatment of acute leukaemias consists of sequential therapy cycles (induction, consolidation, intensification, maintenance therapy) with different cytostatic drugs over a time period of up to 1.5-3 years. Over the last 25 years of clinical trials, a significant rise in the rate of complete remissions as well as an increase in long-term survival has been achieved. Therefore, growing attention is now focused on the long-term effects of antileukaemic treatment. Several cytostatic drugs administered in the treatment of acute leukaemia in childhood are known to cause long-term adverse effects. Anthracyclines may induce chronic cardiotoxicity, alkylating agents are likely to cause gonadal damage and secondary malignancies and the use of glucocorticoids may cause osteonecrosis. Most of the long-term adverse effects have not been analysed systematically. Approaches to minimising long-term adverse effects without jeopardising outcome have included: the design of new drugs such as a liposomal formulation of anthracyclines, the development of anthracycline-derivates with lower toxicity, the development of cardioprotective agents or, more recently, the use of targeted therapy;alternative administration schedules like continuous infusion or timed sequential therapy; and risk group stratification by the monitoring of minimal residual disease. Several attempts have been made to minimise the cardiotoxicity of anthracyclines: decreasing concentrations delivered to the myocardium by either prolonging infusion time or using liposomal formulated anthracyclines or less cardiotoxic analogues, or the additional administration of cardioprotective agents. The advantage of these approaches is still controversial, but there are ongoing clinical trials to evaluate the long-term effects. The use of new diagnostic methods, such as diagnosis of minimal residual disease, which allow reduction or optimisation of dose, offer potential advantages compared with conventional treatment in terms of reducing the risk of severe long-term adverse effects. Most options for minimising long-term adverse effects have resulted from theoretical models and in vitro studies, but only some of the modalities such as the use of dexrazoxane, the continuous infusion of anthracyclines or timed sequential therapy, have been evaluated in prospective, randomised studies in patients. Future approaches to predict severe toxicity may be based upon pharmacogenetics and gene profiling.

The preventive role of deferoxamine against acute doxorubicin-induced cardiac, renal and hepatic toxicity in rats

The iron chelating activity of deferoxamine (DFO) has been exploited to obtain protection against the peroxidative damage in rat heart which was induced by the administration of an acute dose of doxorubicin (DXR, 25 mg x kg(-1), i.v.). The peroxidative lesions were evaluated both biochemically and histopathologically, 48 h after DXR administration. Abnormal biochemical changes including a marked increase in the levels of serum creatine kinase isoenzyme (CK-MB), and lactate dehydrogenase (LDH), as well as elevated serum creatinine, blood urea nitrogen and transaminases (ALT and AST) levels were observed. Myocardial tissue from DXR treated rats showed a marked increase in malondialdehyde (MDA) production and depletion of reduced glutathione (GSH) contents. Similar results were also observed in both kidney and liver tissues. Pretreatment of rats with DFO, given i.p. 30 min prior to DXR injection, substantially reduced the peroxidative damage in the myocardium, hepatic and renal tissues and markedly lowered the serum CK-MB, LDH and the other biochemical variables. The protective effects obtained by DFO administration, however, were not complete and did not reach those of the control group. The significant protection against DXR-induced cardiomyopathy by DFO was evident from the histopathological findings observed by light microscopy. DFO at a dosing level equivalent to 10-fold of that of DXR was useful to obtain protective effects. Higher DFO dosing levels did not, however, show more improvement in the DXR-induced cardiotoxicity and at the same time exhibited hepatoxicity which was confirmed by microscopical examination. These results strongly suggest that DFO protects against acute DXR-induced cardiotoxicity in a dose-dependent manner with recognizing the presence of mild DFO-related biochemical and cytological hepatic toxicity.

American Society of Clinical Oncology clinical practice guidelines for the use of chemotherapy and radiotherapy protectants

PURPOSE

Because toxicities associated with chemotherapy and radiotherapy can adversely affect short- and long-term patient quality of life, can limit the dose and duration of treatment, and may be life-threatening, specific agents designed to ameliorate or eliminate certain chemotherapy and radiotherapy toxicities have been developed. Variability in interpretation of the available data pertaining to the efficacy of the three United States Food and Drug Administration-approved agents that have potential chemotherapy- and radiotherapy-protectant activity-dexrazoxane, mesna, and amifostine-and questions about the role of these protectant agents in cancer care led to concern about the appropriate use of these agents. The American Society of Clinical Oncology sought to establish evidence-based, clinical practice guidelines for the use of dexrazoxane, mesna, and amifostine in patients who are not enrolled on clinical treatment trials.

METHODS

A multidisciplinary Expert Panel reviewed the clinical data regarding the activity of dexrazoxane, mesna, and amifostine. A computerized literature search was performed using MEDLINE. In addition to reports collected by individual Panel members, all articles published in the English-speaking literature from June 1997 through December 1998 were collected for review by the Panel chairpersons, and appropriate articles were distributed to the entire Panel for review. Guidelines for use, levels of evidence, and grades of recommendation were reviewed and approved by the Panel. Outcomes considered in evaluating the benefit of a chemotherapy- or radiotherapy-protectant agent included amelioration of short- and long-term chemotherapy- or radiotherapy-related toxicities, risk of tumor protection by the agent, toxicity of the protectant agent itself, quality of life, and economic impact. To the extent that these data were available, the Panel placed the greatest value on lesser toxicity that did not carry a concomitant risk of tumor protection.

RESULTS AND CONCLUSION

Mesna: (1) Mesna, dosed as detailed in these guidelines, is recommended to decrease the incidence of standard-dose ifosfamide-associated urothelial toxicity. (2) There is insufficient evidence on which to base a guideline for the use of mesna to prevent urothelial toxicity with ifosfamide doses that exceed 2.5 g/m(2)/d. (3) Either mesna or forced saline diuresis is recommended to decrease the incidence of urothelial toxicity associated with high-dose cyclophosphamide use in the stem-cell transplantation setting. Dexrazoxane: (1) The use of dexrazoxane is not routinely recommended for patients with metastatic breast cancer who receive initial doxorubicin-based chemotherapy. (2) The use of dexrazoxane may be considered for patients with metastatic breast cancer who have received a cumulative dosage of 300 mg/m(2) or greater of doxorubicin in the metastatic setting and who may benefit from continued doxorubicin-containing therapy. (3) The use of dexrazoxane in the adjuvant setting is not recommended outside of a clinical trial. (4) The use of dexrazoxane can be considered in adult patients who have received more than 300 mg/m(2) of doxorubicin-based therapy for tumors other than breast cancer, although caution should be used in settings in which doxorubicin-based therapy has been shown to improve survival because of concerns of tumor protection by dexrazoxane. (5) There is insufficient evidence to make a guideline for the use of dexrazoxane in the treatment of pediatric malignancies, with epirubicin-based regimens, or with high-dose anthracycline-containing regimens. Similarly, there is insufficient evidence on which to base a guideline for the use of dexrazoxane in patients with cardiac risk factors or underlying cardiac disease. (6) Patients receiving dexrazoxane should continue to be monitored for cardiac toxicity. Amifostine: (1) Amifostine may be considered for the reduction of nephrotoxicity in patients receiving cisplatin-based chemoth

Phase II trial of liposome-encapsulated doxorubicin, cyclophosphamide, and fluorouracil as first-line therapy in patients with metastatic breast cancer

PURPOSE

To determine the efficacy and safety profile, including the risk for cardiac toxicity, of liposome-encapsulated doxorubicin (TLC D-99), fluorouracil (5-FU), and cyclophosphamide as first-line chemotherapy in patients with metastatic breast cancer (MBC).

PATIENTS AND METHODS

Forty-one women were registered in this phase II study. All patients had measurable disease and no previous chemotherapy for MBC. Treatment consisted of TLC D-99 60 mg/m2 and cyclophosphamide 500 mg/m2 on day 1 and 5-FU 500 mg/m2 on days 1 and 8 every 3 weeks. Serial cardiac monitoring, including endomyocardial biopsies, was performed.

RESULTS

The overall response rate was 73% (95% confidence interval, 57% to 86%). The median duration of response was 11.2 months, the median time to treatment failure was 8.1 months, and the median overall survival duration was 19.4 months. The median number of cycles per patient was 10. The median cumulative dose of TLC D-99 was 528 mg/m2. Ten patients required hospitalization for febrile neutropenia. Nausea/vomiting, stomatitis, and fatigue higher than grade 2 occurred in 12%, 15%, and 41% of patients, respectively. Twenty-one patients reached a cumulative doxorubicin dose greater than 500 mg/m2. Three patients (7%) were withdrawn from the study due to protocol-defined cardiac toxicity, two because of a decrease in left ventricular ejection fraction to < or = 40%, and one because her endomyocardial biopsy result was grade 1.5. One patient had congestive heart failure that was probably nonanthracycline related.

CONCLUSION

This chemotherapy regimen, including TLC D-99, was highly active against MBC and associated with low cardiac toxicity despite high cumulative doses of doxorubicin.

Mucocutaneous reactions to chemotherapy

Chemotherapeutic agents are a widely used treatment modality. Side effects range from common to unusual and may be confused with other cutaneous sequelae of oncologic treatment. The goal of this communication is to elaborate on previous descriptions of the cutaneous manifestations of chemotherapeutic treatment and to discuss more recent findings.

LEARNING OBJECTIVE

At the conclusion of this learning activity, participants should be able to generate a differential diagnosis of possible etiologies for varying patterns of cutaneous involvement in patients receiving chemotherapy and identify the various cutaneous side effects of chemotherapeutic treatment. In addition, they should be able to distinguish life-threatening side effects that require immediate management from more benign manifestations of chemotherapeutic treatment.

Dexrazoxane. A review of its use as a cardioprotective agent in patients receiving anthracycline-based chemotherapy

Dexrazoxane has been used successfully to reduce cardiac toxicity in patients receiving anthracycline-based chemotherapy for cancer (predominantly women with advanced breast cancer). The drug is thought to reduce the cardiotoxic effects of anthracyclines by binding to free and bound iron, thereby reducing the formation of anthracycline-iron complexes and the subsequent generation of reactive oxygen species which are toxic to surrounding cardiac tissue. Clinical trials in women with advanced breast cancer have found that patients given dexrazoxane (about 30 minutes prior to anthracycline therapy; dexrazoxane to doxorubicin dosage ratio 20:1 or 10:1) have a significantly lower overall incidence of cardiac events than placebo recipients (14 or 15% vs 31%) when the drug is initiated at the same time as doxorubicin. Cardiac events included congestive heart failure (CHF), a significant reduction in left ventricular ejection fraction and/or a > or = 2-point increase in the Billingham biopsy score. These results are supported by the findings of studies which used control groups (patients who received only chemotherapy) for comparison. The drug appears to offer cardiac protection irrespective of pre-existing cardiac risk factors. In addition, cardiac protection has been shown in patients given the drug after receiving a cumulative doxorubicin dose > or = 300 mg/m2. It remains to be confirmed that dexrazoxane does not affect the antitumour activity of doxorubicin: although most studies found that clinical end-points (including tumour response rates, time to disease progression and survival duration) did not differ significantly between treatment groups, the largest study did show a significant reduction in response rates in dexrazoxane versus placebo recipients. Dexrazoxane permits the administration of doxorubicin beyond standard cumulative doses; however, it is unclear whether this will translate into prolonged survival. Preliminary results (from small nonblind studies) indicate that dexrazoxane reduces cardiac toxicity in children and adolescents receiving anthracycline-based therapy for a range of malignancies. The long term benefits with regard to prevention of late-onset cardiac toxicity remain unclear. With the exception of severe leucopenia [Eastern Cooperative Oncology Group (ECOG) grade 3/4 toxicity], the incidence of haematological and nonhaematological adverse events appears similar in patients given dexrazoxane to that in placebo recipients undergoing anthracycline-based chemotherapy. Although preliminary pharmacoeconomic analyses have shown dexrazoxane to be a cost-effective agent in women with advanced breast cancer, they require confirmation.

CONCLUSIONS

Dexrazoxane is a valuable drug for protecting against cardiac toxicity in patients receiving anthracycline-based chemotherapy. Whether it offers protection against late-onset cardiac toxicity in patients who received anthracycline-based chemotherapy in childhood or adolescence remains to be determined. Further clinical experience is required to confirm that it does not adversely affect clinical outcome, that it is a cost-effective option, and to determine the optimal treatment regimen.

Dexrazoxane: A New Cardioprotective Agent

Objective:

To review the literature discussing the use of dexrazoxane (e.g., Zinecard, ICRF-187) to prevent doxorubicin-induced cardiotoxicity.

Data Sources:

Pertinent English-language reports of studies in humans were retrieved from a MEDLINE search (January 1980-January 1997); search terms included chelating agents, razoxane, dexrazoxane, Zinecard, ICRF-187, ADR-529, and ICRF-159.

Study Selection:

Representative articles discussing the chemistry, pharmacology, pharmacokinetics, dosing, and administration of dexrazoxane and those discussing clinical trials were selected.

Data Extraction:

Data were extracted and analyzed if the information was relevant and consistent. Studies were selected for review in the text on the basis of study design and clinical end points.

Data Synthesis:

Dexrazoxane is a chemoprotective agent developed to prevent cardiac tissue toxicity. Dexrazoxane exerts a cardioprotective effect with some clinically significant toxicities; it may also interfere with the antitumor activity of doxorubicin. Until there are sufficient data to support its use in first-line supportive care therapy, dexrazoxane should be reserved for use in patients responding to doxorubicin-based chemotherapy but who have risk factors for cardiac toxicity or have received a cumulative doxorubicin bolus dose of 300 mg/m2.

Conclusions:

The management of doxorubicin-induced cardiotoxicity has led to the development of supportive care drugs that specifically counteract the dose-limiting toxicities. Dexrazoxane may not completely eliminate the concern about doxorubicin-induced cardiotoxicity, but it may open new avenues for continuing doxorubicin-based chemotherapy.

[Pediatric aspects of anthracycline cardiotoxicity and practical implications for prevention]

Discovered during the sixties, anthracycline antibiotics are today widely used anti-cancer drugs. Their potentially fatal cardiac toxicity, which is related in part to the total cumulative dose, has been described since 1967. The aim of this paper is to describe their biological and clinical toxic effects on the heart, especially of children, and to propose prevention guidelines. The mechanisms of cardiac toxicity, with their destructive consequences on functional myocytes reserve, are shortly recalled. Acute, sub-acute and chronic clinical aspects of anthracycline's cardiomyopathy are the subject of a literature review. In Pediatric Oncology, the prolonged survival usually observed allows delayed congestive heart failure to occur by myocardial reserve insufficiency, as hemodynamic needs are quickly increasing, especially at the end of the somatic growth. Furthermore, the frequency of cardiac abnormalities is increasing with time after therapy, reaching about half of the explored patients after 15 years. The main known methods to prevent such a toxicity are reviewed. The parcimonious use of anthracyclines is already seen in children. Every method to decrease the maximal plasma concentration of the drug (weekly schedule or prolonged infusion) has to be considered. The active cardioprotectant agent such as ICRF-187, is in clinical development. Detection, prevention, and therapy of cardiac abnormalities, which are likely to precede delayed heart failure, still remains a difficult problem in these more and more numerous children to be cured of cancer.