Protective effect of the bispiperazinedione ICRF-187 against doxorubicin-induced cardiac toxicity in women with advanced breast cancer

High incidence of adriamycin cardiotoxicity in children even at low cumulative doses: role of radionuclide cardiac angiography

BACKGROUND/PURPOSE

Adriamycin (doxorubicin), a chemotherapeutic agent commonly used in the treatment of pediatric solid tumors, is known to have a dose-related cardiotoxicity, which is reported to be more common in children. The clinical manifestation of this is congestive cardiac failure (CHF), and this is fatal in 50% of the cases. Various strategies, including prospective multiple gated acquisition (MUGA) scan for early detection of the onset of cardiac damage has been recommended to decrease this fatality caused by cardiotoxicity.

METHODS

All children receiving Adriamycin for solid tumors, registered at our pediatric solid tumor clinic from January 1998 through June 1999, were included in the study. Cardiotoxicity was evaluated by using electrocardiogram (ECG)-gated radionuclide cardiac angiography (MUGA scan).

RESULTS

MUGA scans were performed on 55 patients in the above-mentioned period of 18 months. Twenty-three patients had only 1 baseline MUGA scan done, 12 of these are awaiting further studies at appropriate time and 11 are either dead or lost to follow-up. Of the remaining 32 patients, 13 have shown evidence of cardiotoxicity on MUGA scan done at a cumulative dose of 180 to 200 mg/m(2), in the form of decrease in left ventricular ejection fraction (LVEF) or abnormality in myocardial movements. Three of these 13 patients had clinical evidence of CHF. In 10 patients, timely discontinuation of Adriamycin, based on the MUGA report, probably has helped avoid the development of CHF.

CONCLUSION

Routine monitoring of all children receiving Adriamycin is required to avoid the mortality and morbidity of Adriamycin-related cardiotoxicity, which may develop at relatively low cumulative doses also.

Left ventricular dysfunction predicted by early troponin I release after high-dose chemotherapy

OBJECTIVES

We investigated the role of cardiac troponin I (cTnI) in patients with aggressive malignancies treated with high-dose chemotherapy (HDC).

BACKGROUND

High dose chemotherapy is potentially limited by cardiac toxicity. Considering the fact that cardiac dysfunction may become clinically evident weeks or months after HDC, the availability of an early marker of myocardial injury, able to predict late ventricular impairment, is a current need.

METHODS

We measured, in 204 patients (45+/-10 years) affected by cancer resistant to conventional treatment, the cTnI plasma concentration after every single cycle of HDC. According to the cTnI value (< or = or >0.4 ng/ml), patients were divided into a troponin positive (cTnI+, n = 65) and a troponin negative (cTnI-, n = 139) group. All patients underwent echocardiographic examination during the following seven months.

RESULTS

In the cTnI- group, left ventricular ejection fraction (LVEF) progressively decreased after HDC, reaching a maximal reduction after three months; however, myocardial depression was transient and no longer detectable at later follow-up. By contrast, in the cTnI+ group LVEF reduction was more marked and still evident at the end of the follow-up. In cTnI+ patients, a close relationship between the short-term cTnI increment and the greatest LVEF reduction was found (r = -0.87, p<0.0001).

CONCLUSIONS

The elevation of cTnI in patients undergoing HDC for aggressive malignancies accurately predicts the development of future LVEF depression. In this setting, cTnI can be considered a sensitive and reliable marker of acute minor myocardial damage with relevant clinical and prognostic implications.

The therapeutic potential of iron chelators

In recent years there has been much interest in the development of iron (Fe) chelators for treatment of a number of clinical conditions in addition to beta-thalassaemia. These include cancer, anthracycline-mediated cardiotoxicity, malaria, AIDS and the severe neurodegenerative disease, Friedreich's ataxia. In this review I will discuss the most recent advances achieved in the potential treatment of these conditions using Fe chelators.

[Experiences with sodium selenite in treatment of acute and late adverse effects of radiochemotherapy of head-neck carcinomas. Cytoprotection Working Group in AK Supportive Measures in Oncology Within the scope of MASCC and DKG]

BACKGROUND

The principle of cytoprotection became a new supportive strategy in oncology during the last decade. Two principal ways of cytoprotection are well known in practice: the addition of external free thiols (for example amifostine) or the activation of internal detoxification-pathways (for example the activation of glutathione peroxidase) by administration of additional selenium.

OWN EXPERIENCES

We report about our experiences in both fields: At first we could show the significant possibilities of cytoprotection to reduce the acute hematological and non hematological toxicities of a simultaneous radiochemotherapy (2 cycles Carboplatin, 2 Gy single dose, 60 Gy total dose) of head and neck cancer patients. After 1 year the survival of amifostine-protected patients was better compared to the control, the rate of severe late complications (xerostomia Grade 3/4) was decreased from 57% to 14%. At second we report about the usage of selenium in the treatment of paravasats (10 patients) and interstitial lymph edema (20 patients). In the acute intervention group 9/10 patients resolved from the paravasats without any necrosis. In the late intervention group 12/20 patients showed reduced edema. Nine of 15 patients with a supraglottic edema and subsequent dyspnoea resolved under treatment without any tracheostomy.

CONCLUSION

On the base of these data we have planned a phase-I/II study to investigate the chances of both cytoprotectants alone and in combination in order to get the most favorable supportive regimen for our basic type of radiochemotherapy.

Metastatic breast cancer

The unfortunate reality of metastatic breast cancer is that all treatment is palliative in nature. This is a disease that currently has no cure and for which therapy is directed towards accentuating survival and relieving symptoms. Current technology allows the prediction and detection of metastases earlier and with greater accuracy. These achievements need to be consolidated by the discovery of innovative therapies that can alter the inevitable outcome of this disease.

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

Role of postmastectomy radiotherapy: A medical oncology perspective

Current practice in the management of patients who undergo a mastectomy does not usually include radiotherapy. Data from both meta-analyses and two randomized studies challenge this approach. Part of the skepticism about postmastectomy radiotherapy is what biological rationale would justify this intervention. Hellman has proposed the spectrum hypothesis, which explains the potential indication for additional local therapy for such patients. Another concern is the risk for increased toxicity, especially cardiotoxicity in patients who receive anthracycline-based adjuvant regimens. The addition of new agents (eg, Herceptin) also requires careful monitoring with regard to toxicity. Furthermore, the timing of radiation with chemotherapy is problematic. Overall, there is now evidence to support a role for postmastectomy radiotherapy, but further studies are needed on how best to incorporate this modality in multimodality treatment of early-stage breast cancer.

Glutamine protects against doxorubicin-induced cardiotoxicity

Doxorubicin (DOX) dose-intensive therapy for breast cancer is limited by a cardiomyopathy that often results in overt congestive heart failure. We hypothesized that dietary glutamine (GLN) can diminish DOX-induced cardiotoxicity by maintaining tissue glutathione (GSH) levels and thus preventing the proposed mechanism of cardiac injury: oxidation.

METHODS

Forty-two female Fisher 344 rats were randomized into one of six groups: GLN + saline (SAL), GLN + DOX, freamine (FA) + SAL, FA + DOX, H2O + SAL, and H2O + DOX. Rats were pair-fed chow and gavaged with 1 g/kg/day GLN or an isonitrogenous amount of FA or H2O for 28 days. Rats were injected intravenously with a single dose of SAL or 9 mg/kg DOX on day 7 of gavage. At 28 days (21 days post-DOX), rats were sacrificed and blood and cardiac tissue were assayed for GLN and GSH content and lipid peroxidation (LP).

RESULTS

There were no differences in cardiac GSH levels and cardiac lipid peroxidation in GLN + SAL versus GLN + DOX groups. However, blood and cardiac GSH levels were significantly decreased in H2O + DOX and FA + DOX groups compared to controls (H2O + SAL and FA + SAL).

CONCLUSION

These data suggest that dietary GLN supplementation may diminish DOX-induced oxidative damage and thus cardiotoxicity through upregulation of cardiac GSH metabolism.

Anthraquinone-induced cell injury: acute toxicity of carminomycin, epirubicin, idarubicin and mitoxantrone in isolated cardiomyocytes

Acute toxic effects of the antineoplastic anthraquinones carminomycin, epirubicin, idarubicin and mitoxantrone were studied in primary cultures of cardiomyocytes, which were isolated from adult rats. Both time- and concentration-dependent changes of cell structure and viability (trypan blue exclusion) following incubation of myocytes with subclinical, clinical and toxic concentrations of the anthraquinones were examined by light microscopy. The area under the decay curve of viable and rod-shaped myocytes was used to express cytotoxicity of the drugs. Mitoxantrone was found to reduce cell viability and number of rod-shaped cells to the greatest extent, followed by carminomycin, idarubicin and epirubicin. A significantly lower accumulation in cardiomyocytes was obtained with epirubicin and idarubicin compared with carminomycin. An inhibitory effect on oxygen consumption by the cells occurred already at 0.1 microM with epirubicin, whereas inhibition caused by other anthraquinones was less pronounced. Our data indicate a weak association of net accumulation and the toxicity parameter IC50 for carminomycin and idarubicin. In contrast to these results, a more significant correlation of cytotoxicity and anthraquinone lipophilicity was found, which suggests that the lipophilic character of a particular anthraquinone may be an important factor in drug-induced acute cardiotoxicity.

Inhibition of p34cdc2 dephosphorylation in DNA damage- and topoisomerase II inactivation-induced G2 arrests in HL-60 cells

Doxorubicin induces DNA breakage by stabilizing a cleavable topoisomerase II-DNA complex. In contrast, topoisomerase II catalytic inhibitor ICRF-193 and uncoupling inhibitor aclarubicin interfere with the cleavable complex formation. We analysed combination effects of these drugs using two-dimensional flow cytometry of DNA content and the terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end-labelling assay. Both ICRF-193 and aclarubicin attenuated the cytotoxic effect of doxorubicin on HL-60 cells (85% and 46% maximum reduction, respectively), which suggested that doxorubicin exerts its cytotoxic effect at least partially through the topoisomerase II-dependent DNA cleavage. Doxorubicin and ICRF-193 both induced G2 arrest in HL-60 cells, by which they may have reduced the cytotoxic effect of vincristine. Indeed, although ICRF-193 inhibited doxorubicin-induced apoptosis, ICRF-193 and doxorubicin cooperated in arresting HL-60 cells at G2 phase. These results indicated that G2 arrest was caused not only by DNA damage but also through a DNA damage-free, topoisomerase II inactivation-induced pathway. Western blot analysis showed that both types of G2 arrest were mediated by the inhibition of p34cdc2 dephosphorylation.

Drug-induced heart failure

Heart failure is a clinical syndrome that is predominantly caused by cardiovascular disorders such as coronary heart disease and hypertension. However, several classes of drugs may induce heart failure in patients without concurrent cardiovascular disease or may precipitate the occurrence of heart failure in patients with preexisting left ventricular impairment. We reviewed the literature on drug-induced heart failure, using the MEDLINE database and lateral references. Successively, we discuss the potential role in the occurrence of heart failure of cytostatics, immunomodulating drugs, antidepressants, calcium channel blocking agents, nonsteroidal anti-inflammatory drugs, antiarrhythmics, beta-adrenoceptor blocking agents, anesthetics and some miscellaneous agents. Drug-induced heart failure may play a role in only a minority of the patients presenting with heart failure. Nevertheless, drug-induced heart failure should be regarded as a potentially preventable cause of heart failure, although sometimes other priorities do not offer therapeutic alternatives (e.g., anthracycline-induced cardiomyopathy). The awareness of clinicians of potential adverse effects on cardiac performance by several classes of drugs, particularly in patients with preexisting ventricular dysfunction, may contribute to timely diagnosis and prevention of drug-induced heart failure.

Daunorubicin-induced apoptosis in rat cardiac myocytes is inhibited by dexrazoxane

-The clinical efficacy of anthracycline antineoplastic agents is limited by a high incidence of severe and usually irreversible cardiac toxicity, the cause of which remains controversial. In primary cultures of neonatal and adult rat ventricular myocytes, we found that daunorubicin, at concentrations </=1 micromol/L, induced myocyte programmed cell death within 24 hours, as defined by several complementary techniques. In contrast, daunorubicin concentrations >/=10 micromol/L induced necrotic cell death within 24 hours, with no changes characteristic of apoptosis. To determine whether reactive oxygen species play a role in daunorubicin-mediated apoptosis, we monitored the generation of hydrogen peroxide with dichlorofluorescein (DCF). However, daunorubicin (1 micromol/L) did not increase DCF fluorescence, nor were the antioxidants N-acetylcysteine or the combination of alpha-tocopherol and ascorbic acid able to prevent apoptosis. In contrast, dexrazoxane (10 micromol/L), known clinically to limit anthracycline cardiac toxicity, prevented daunorubicin-induced myocyte apoptosis, but not necrosis induced by higher anthracycline concentrations (>/=10 micromol/L). The antiapoptotic action of dexrazoxane was mimicked by the superoxide-dismutase mimetic porphyrin manganese(II/III)tetrakis(1-methyl-4-peridyl)porphyrin (50 micromol/L). The recognition that anthracycline-induced cardiac myocyte apoptosis, perhaps mediated by superoxide anion generation, occurs at concentrations well below those that result in myocyte necrosis, may aid in the design of new therapeutic strategies to limit the toxicity of these drugs.

A calcium antagonist protects against doxorubicin-induced impairment of calcium handling in neonatal rat cardiac myocytes

The effects of doxorubicin (DOX) on intracellular calcium transients and the cardioprotective effects of a calcium antagonist on DOX-induced impairment of calcium handling were examined in neonatal rat cultured cardiac myocytes. Cultured cardiac myocytes isolated from neonatal Wistar-Kyoto rats were treated with DOX for 24 h. Field-stimulated calcium transients in single myocytes were measured in the presence or absence of isoproterenol using fura-2/AM. Calcium transients were also measured after the addition of DOX to myocytes pretreated with a calcium antagonist, benidipine. DOX reduced the amplitude, maximum velocity of increase and decrease of calcium transients and prolonged the time course of calcium transients and impaired the beta-adrenoceptor responsiveness of calcium transients in a concentration-dependent manner. The DOX-induced impairment of calcium transients and beta-adrenoceptor responsiveness was improved by 10(-8) mol/L of benidipine. However, these improvements decreased with increasing concentrations of benidipine. DOX impaired both the mobilization and removal of intracellular calcium ions in contraction-relaxation cycles and the response of calcium transients to beta-adrenoceptor stimulation. Appropriate concentration of benidipine ameliorated DOX-induced impairment of calcium dynamics, suggesting that benidipine, a long-acting calcium antagonist, has potential clinical usefulness on DOX-induced abnormal calcium handling.

Cytoprotection in the treatment of pediatric cancer: review of current strategies in adults and their application to children

BACKGROUND

The protection of patients from the acute and/or chronic toxicity of antineoplastic therapy has become a major concern of oncology centers around the world. However, most of the effort has been directed toward the adult population, and limited studies have been performed in the group that may gain the most from such strategies, namely, children.

PROCEDURES

The MedLine and CancerLit databases were surveyed, and the relevant biomedical literature on cytoprotection during antineoplastic treatment was analyzed.

RESULTS

Cytotoxicity from antineoplastic therapy customarily is addressed by altering dosing schedules, a technique that can seriously impact the efficacy of the therapy. Colony stimulating factors have been used posttherapy to stimulate recovery from neutropenia, and various agents have been proposed as pretherapy cytoprotectors. Trials in adults have produced mixed results, and, to date, only amifostine and dexrazoxane have been approved as cytoprotectors for very narrow indications. Few trials have been performed in children, although these patients often can look forward to long-term remission.

CONCLUSIONS

To prevent permanent toxicities from antineoplastic therapies that impact long-term pediatric survivors, the experience gained in adults should be extended more aggressively to children, and formal, randomized trials should be performed to determine the type of protection most suitable for the pediatric population.

Dexrazoxane (ICRF-187)

1. Dexrazoxane (ICRF-187) is the only clinically approved drug for use in cancer patients to prevent anthracycline mediated cardiotoxicity. 2. The mode of action appears to be mainly due to the potential of the drug to remove iron from iron/anthracycline complexes and thus reduce free radical formation by these complexes. 3. Dexrazoxane also influences cell biology by its ability to inhibit topoisomerase II and its effects on the regulation of cellular iron homeostasis. 4. Although the cardioprotective effect of dexrazoxane in cancer patients undergoing chemotherapy with anthracyclines is well documented, the potential of this drug to modulate topoisomerase II activity and cellular iron metabolism may hold the key for future applications of dexrazoxane in cancer therapy, immunology, or infectious diseases.

Comparative open, randomized, cross-over bioequivalence study of two intravenous dexrazoxane formulations (Cardioxane and ICRF-187) in patients with advanced breast cancer, treated with 5-fluorouracil-doxorubicin-cyclophosphamide (FDC)

The purpose of this study was to compare the pharmacokinetic disposition of two intravenous dexrazoxane formulations, and their effects on doxorubicin's kinetics and metabolism. Plasma concentration versus time curves and pharmacokinetic parameters of dexrazoxane given as Cardioxane (dexrazoxane hydrochloride salt) and ICRF-187 reference formulation (dexrazoxane base) were determined and compared. Both formulations were administered as a single intravenous infusion prior to 5-fluorouracil-doxorubicin-cyclophosphamide administration. In addition, the pharmacokinetics of doxorubicin and its metabolites were studied after dexrazoxane administration. A total of 15 patients with advanced breast cancer participated in this open, randomized, cross-over study and 12 patients were evaluable. Plasma concentrations of dexrazoxane, doxorubicin and doxorubicin metabolites were determined by high-performance liquid chromatography in samples obtained in the 72 h after drug administration. No statistically significant differences were found in the tested kinetic parameters when the two products were compared by analysis of variance (ANOVA) on log-transformed data. Cardioxane fulfilled the bioequivalence criteria when compared with ICRF-187 reference formulation for all of the investigated parameters (AUC, t1/2beta, Vdss, Cl(tot), Cl(ren)). The parametric 90% confidence intervals were contained within the bioequivalence interval (0.8-1.25). Pharmacokinetic parameters and metabolism of doxorubicin were not different after the administration of either Cardioxane or ICRF-187 formulation. From the results of this study it can be concluded that the two formulations can be considered bioequivalent with regard to extent of absorption (AUC and Vdss) and elimination (t1/2beta, Cl(tot) and Cl(ren)).

Cardiotoxicity of doxorubicin: effects of 21-aminosteroids

The purposes of this study were to investigate in vivo the effects of two lazaroids,U-74389G (21-[4-(2,6-di-1-pyrrolidinyl-4-pyrimidinyl)-1-piperazinyl]-pregna-1,4,9 (11)-triene-3,20-dione (2)-2-butenenedionate) and U-83836E (-)-2-[[4-(2,6-di-1-pyrrlidinyl-4-pyrimidinyl)-1-piperazinyl]methy l]-3,4-dihydro-2,5,7,8-tetramethyl-2H-1-benzopyran-6-ol, dihydrochloride against the cardiotoxicity induced by doxorubicin in rat and the mechanisms underlying such a toxicity. Doxorubicin (DXR) administered intraperitoneally (5 mg/kg 4 times per week for 1 week) induced significant decrease of body weight, ECG alterations and 100% mortality. The lazaroids used in this study did not protect from DXR-induced cardiotoxicity. Our results showed that the compound U-74389G delayed, but did not reduce DXR-induced mortality, and did not prevent body weight loss and ECG changes. The compound U-83836E was unable to modify any toxic effects induced by DXR. These data indicate that oxygen free radicals and the subsequent increase in intracellular calcium are only steps of DXR progressive general toxicity that leads to cardiac injury. In conclusion, we propose that the 21-aminosteroids, potent inhibitors of membrane lipid peroxidation, alone are not enough to protect from DXR toxic effects.

Coincident acute myelogenous leukemia and ischemic heart disease: use of the cardioprotectant dexrazoxane during induction chemotherapy

Treatment of acute myelogenous leukemia is challenging in the setting of ischemic heart disease because anthracycline and anthracenedione drugs used in induction chemotherapy may potentiate myocardial dysfunction. We have managed two patients with coincident acute myelogenous leukemia and ischemic heart disease with the cardioprotectant drug dexrazoxane (ICRF-187), administered before each dose of mitoxantrone or idarubicin. Both patients tolerated their induction chemotherapy, developed marrow hypoplasia from chemotherapy, and achieved clinical remission. Dexrazoxane may have a role as a cardioprotectant in the treatment of select patients with acute myelogenous leukemia.

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.

Urine 8-oxo-7,8-dihydro-2-deoxyguanosine vs. 5-(hydroxymethyl) uracil as DNA oxidation marker in adriamycin-treated patients

We measured the base 5-(hydroxymethyl) uracil (HMUra) and the nucleoside 8-oxo-7,8-dehydro-2'-deoxyguanosine (8-oxo-dGuo) in urine of adriamycin-treated cancer patients. Adriamycin has been shown to generate oxygen free radicals by various mechanisms. HMUra and 8-oxo-dGuo are two known lesions of DNA, produced by oxygen free reaction on thymine and 2'-deoxyguanosine, respectively. HMUra was measured by GC-MS/isotopic dilution and 8-oxo-dGuo by HPLC/EC, both after prepurification by semipreparative HPLC. Here we report the results of a study involving 20 cancer patients treated with flash doses of ADR. We found that urine HMUra is significantly increased (HMUra (nmol/24h): 80.8 8.44 vs. 98.7+/-6.87; p < 0.01) 24h after administration of the drug, while 8-oxo-dGuo did not show any significant variation. Urine HMUra seems to be a suitable short-term marker of DNA alterations by oxygen free radicals.

Marked improvements in outcome with chemotherapy alone in paediatric acute myeloid leukemia: results of the United Kingdom Medical Research Council's 10th AML trial. MRC Childhood Leukaemia Working Party

359 eligible children with acute myeloid leukaemia (AML) entered the MRC AML 10 trial between May 1988 and March 1995. Patients received four courses of intensive induction and consolidation chemotherapy, with or without subsequent autologous (A-BMT) or allogeneic (allo-BMT) bone marrow transplant. There were randomized comparisons of thioguanine versus etoposide in induction and of A-BMT versus not. Allo-BMT was recommended for patients with a HLA-matched sibling and was evaluated by donor versus no donor comparison. The complete remission rate was 92%. In first remission there were 20 deaths during consolidation chemotherapy and 11 after BMT (8/61 allo-BMTs. 1/60 A-BMTs and 2/4 matched unrelated donor transplants). The relapse rate was low, decreasing from 26% in the first year to 2% in the fourth. Long-term outcome was excellent with survival at 7 years from entry of 56% and event-free survival of 48%. There were no significant differences between thioguanine and etoposide, whereas both A-BMT and allo-BMT reduced relapse risk but did not produce a significant survival benefit. It appears that over half the children entered into AML 10 are cured, a result which compares favourably with other reported series. We conclude that four courses of intensive chemotherapy are an effective approach to the treatment of paediatric AML, which avoids the acute toxicity and long-term side-effects of BMT and also avoids the need for prolonged maintenance therapy or cranial irradiation.

[Heart pathology of extracardiac origin. VII. Heart and neoplasms]

Cardiac alterations of neoplastic diseases can be due to direct invasion produced by primary cardiac tumors or more frequently secondary to local compression of vascular structures by extracardiac neoplasms, such as superior vena cava syndrome. One of the most important alterations is the cardiotoxicity of anticancer treatments, either chemotherapy drugs or radiotherapy techniques. These treatments cause acute and/or chronic cardiotoxicity that the oncologist and the cardiologist must be aware of. For instance, 4.5% to 7% of patients that have been treated with anthracyclines may suffer cardiac failure in their lifetime. The pathogenesis is still not clear. There is currently a lot of research on cardioprotectors, but nowadays the only one approved by the FDA is dexrazoxane, which is used on breast cancer patients treated with adriamycin.

Favorable outcome after 1-year treatment of childhood T-cell lymphoma/T-cell acute lymphoblastic leukemia

BACKGROUND

For T-malignancies in children a poor prognosis is reported. In these malignancies a combination of lymphoma and leukemia is commonly seen at presentation and most patients are treated according to protocols for acute lymphoblastic leukemia (ALL). These protocols are often designed for the majority of ALL cases, i.e., progenitor-B-ALL. In pediatric lymphoblastic non-Hodgkin's lymphoma without bone marrow infiltration various protocols have been used. The most frequently reported regimens show variable survival rates between 40 and 75%.

PATIENTS AND METHODS

From 1989 we have treated 32 consecutive patients with T-cell malignancies, irrespective of localization, with a protocol consisting of a 4-agent induction treatment followed by high doses of methotrexate, and cytosine-arabinoside and intensified bleomycin, adriamycin, cyclophosphamide, vin cristin, prednisone (BACOP) courses. Treatment duration for each patient was 1 year. Twenty-one of the 32 patients had stage IV disease. Follow-up ranged from 1.6 to 7.6 years (median 4.2 years).

RESULTS

Overall event-free survival (EFS) was 72%, while in those with stage IV disease it was 67%. No therapy-related deaths occurred. Neither stage, initial leukocyte value, mediastinal involvement, bone marrow involvement, nor the presence of CD1, CD3, CD4, CD8, or CD10 epitopes was prognostically significant. Evaluation of toxicity revealed a minimal decrease of carbon monoxide diffusion and cardiac shortening fraction.

CONCLUSION

A relatively short but intensive chemotherapy can be used in T-cell malignancies. The EFS is satisfying, but larger studies are needed.

Clinical relevance of radionuclide angiography and antimyosin immunoscintigraphy for risk assessment in epirubicin cardiotoxicity

BACKGROUND

Cardiotoxicity is the major limiting factor in anthracycline chemotherapy of advanced neoplastic disease. Epirubicin shows a more favorable therapeutic index than does doxorubicin, but it is still cardiotoxic. Limited data regarding epirubicin cardiotoxicity are available, and suggested guidelines for doxorubicin with left ventricular ejection fraction (LVEF) measurement may not be empirically useful for epirubicin therapy. This study evaluates the diagnostic role of antimyosin immunoscintigraphy for early identification of patients at risk for late pump dysfunction from cardiotoxicity induced by high-dose administration of epirubicin up to high cumulative dosages.

METHODS AND RESULTS

Chemotherapy with epirubicin was administered to 36 patients with cancer at a dosing rate of 160 mg/m2 as a bolus injection every 21 days to a cumulative dosage of 960 mg/m2. Radionuclide angiography (LVEF) and antimyosin immunoscintigraphy with heart-lung ratio (HLR) measurements were performed before chemotherapy, at intermediate cumulative epirubicin dosages, at the end of treatment, and during the follow-up. LVEF decreased significantly at the end of the treatment and after therapy discontinuation. HLR values were significantly increased at intermediate epirubicin dosage levels and continued to increase to the end of the treatment but thereafter remained substantially unmodified for 3 to 6 months after therapy discontinuation. A value of HLR >1.85 at intermediate epirubicin dosage level showed a sensitivity of 95% and a specificity of 57% as a predictor of late LVEF impairment.

CONCLUSIONS

LVEF appears more useful at high cumulative dosages and during follow-up to monitor late pump dysfunction, whereas HLR may be effective during the early phase of the therapy in determining which patients are at risk for development of late cardiac dysfunction.

An angiotensin-converting enzyme inhibitor protects against doxorubicin-induced impairment of calcium handling in neonatal rat cardiac myocytes

1. The effects of doxorubicin (DOX) on intracellular calcium transients were examined in neonatal rat cultured cardiac myocytes, as were the cardioprotective effects of an angiotensin-converting enzyme (ACE) inhibitor on DOX-induced impairment of calcium handling. 2. Cultured cardiac myocytes isolated from neonatal Wistar-Kyoto rats were treated with DOX for 24 h. Field-stimulated calcium transients in single myocytes were measured in the presence or in the absence of isoproterenol using fura-2/AM. Calcium transients were also measured after the addition of DOX to myocytes pretreated with M-I (an active metabolite of delapril HCL, an ACE inhibitor. 3. Doxorubicin reduced the amplitude and maximum velocity of increase and decrease of calcium transients, prolonged the time-course of calcium transients and impaired the beta-adrenoceptor responsiveness of calcium transients in a dose-dependent manner. The DOX-induced impairment of calcium transients and beta-adrenoceptor responsiveness was improved by M-I. 4. Doxorubicin impaired both the mobilization and sequestration of intracellular calcium ions in contraction-relaxation cycles and the response of calcium transients to beta-adrenoceptor stimulation. The ACE inhibitor ameliorated DOX-induced impairment of calcium dynamics, suggesting ihat M-I, an active metabolite of delapril, protects against DOX-induced abnormal calcium handling leading to cardiac dysfunction.

Modulation of transferrin receptor expression by dexrazoxane (ICRF-187) via activation of iron regulatory protein

Dexrazoxane (ICRF-187) has recently been demonstrated to reduce cardiac toxicity induced by chemotherapy with anthracyclines, although the reason for this phenomenon has remained obscure thus far. In order to investigate whether ICRF-187 might exert its effects by modulating iron metabolism, we studied the drug's potential to influence the maintenance of iron homeostasis in two human cell lines. We demonstrate that ICRF-187 enhanced the binding affinity of iron regulatory protein (IRP), the central regulatory factor for posttranscriptional iron regulation, to RNA stem loop structures, called iron responsive elements (IRE), in THP-1 myelomonocytic as well as K562 erythroleukemic cells. Increased IRE/IRP interaction was paralleled by an elevation of transferrin receptor (trf-rec) mRNA levels which, according to the well-established mechanism of posttranscriptional iron regulation, was likely due to stabilisation of trf-rec mRNA by IRP. Subsequently, ICRF-187 treatment of cells increased trf-rec surface expression and enhanced cellular iron uptake. All these events, i.e. IRP activation, stabilisation of trf-rec mRNA and increased surface expression of the protein in response to ICRF-187, follow a dose-response relationship. Increased cellular uptake and sequestration of iron in response to ICRF-187 may contribute to the protective activity of ICRF-187 by reducing the iron-anthracycline complex and iron-catalysed generation of hydroxyl radicals via the Haber-Weiss reaction.

Use of ICRF-187 for prevention of anthracycline cardiotoxicity in children: preliminary results

The objective of this study is to assess the efficacy of ICRF-187 as a protective agent against anthracycline cardiotoxicity. Cardiac function was evaluated by echocardiography before and after each cycle of anthracycline chemotherapy associated with ICRF-187 and compared with that of a second group receiving anthracycline chemotherapy without ICRF-187. The patients were a group of 15 consecutive children affected with various types of solid tumors who were treated with either doxorubicin-daunomycin or epirubicin (average doses 340 and 280 mg/m2, respectively), and treatment was associated with ICRF-187. A second group of 15 consecutive children affected with different malignancies were simultaneously treated with either doxorubicin-daunomycin or epirubicin (average doses 309 and 270 mg/m2, respectively), but without ICRF-187 association. None of the patients treated with anthracyclines and ICRF-187 association showed abnormalities on echocardiographic examination. In the second group of patients treated with anthracyclines but without ICRF-187 association, we observed a decrease in the left ventricular ejection fraction to < 55% and a decrease in the left ventricular fractional shortening to < 28% in two patients (13.3%). One of these (6.6%) showed a dilatative cardiomyopathy. Both groups of patients were treated with low doses of anthracyclines. Although this study was not randomized, in patients without ICRF-87 cardioprotection, there was a trend for a worse evolution with one case of clinical cardiomyopathy as well as subclinical cardiac abnormalities.

A risk-benefit assessment of anthracycline antibiotics in antineoplastic therapy

The anthracycline antibiotics comprise a group of cytotoxic compounds with wide-ranging activity against human malignancies. They are used extensively for curative, adjuvant and palliative therapy, both as single agents and in combination regimens. They produce a number of adverse effects, some of which are shared by other cytotoxic drugs. The most important adverse effect is cardiotoxicity, which is unique to this class of compounds. Strategies have been devised to circumvent these adverse effects, including the development of less toxic analogues, alterations in scheduling, the addition of cardioprotectant agents and methods of monitoring for cardiac abnormalities.