Subacute cardiotoxicity caused by anthracycline therapy in children: can dexrazoxane prevent this effect?

Evaluation of the cost-effectiveness of dexrazoxane for the prevention of anthracycline-related cardiotoxicity in children with sarcoma and haematologic malignancies: a European perspective

Background

Anthracycline-treated childhood cancer survivors are at higher risk of cardiotoxicity, especially with cumulative doses received above 250 mg/m². Dexrazoxane is the only option recommended for cardiotoxicity prevention in high-risk patients supported by randomised trials but its cost-effectiveness in paediatric cancer patients has not been established.

Methods

A cost-effectiveness model applicable to different national healthcare system perspectives, which simulates 10,000 patients with either sarcoma or haematologic malignancies, based upon baseline characteristics including gender, age at diagnosis, cumulative anthracycline dose and exposure to chest irradiation. Risk equations for developing congestive heart failure and death from recurrence of the original cancer, secondary malignant neoplasms, cardiac death, pulmonary death, and death from other causes were derived from published literature. These are applied to the individual simulated patients and time until development of these events was determined. The treatment effect of dexrazoxane on the risk of CHF or death was based upon a meta-analysis of randomised and non-randomised dexrazoxane studies in each tumour type. The model includes country specific data for drug and administration costs, all aspects of heart failure diagnosis and management, and death due to different causes for each of the five countries considered; France, Germany, the UK, Italy, and Spain.

Results

Dexrazoxane treatment resulted in a mean QALY benefit across the five countries ranging from 0.530 to 0.683 per dexrazoxane-treated patient. Dexrazoxane was cost-effective for paediatric patients receiving anthracycline treatment for sarcoma and for haematologic malignancies, irrespective of the cumulative anthracycline dose received. The Incremental Cost Effectiveness Ratio (ICER) was favourable in all countries irrespective of anthracycline dose for both sarcoma and haematological malignancies (range: dominant to €2196). Individual ICER varied considerably according to country with dominance demonstrated for dexrazoxane in Spain and Italy and ratios approximately double the European average in the UK and Germany.

Conclusions

Dexrazoxane is a highly cost-effective therapy for the prevention of anthracycline cardiotoxicity in paediatric patients with sarcoma or haematological malignancies in Europe, irrespective of the healthcare system in which they receive treatment. These benefits persist when patients who receive doses of anthracycline > 250 mg/m² are included in the model.

Iron chelators with topoisomerase-inhibitory activity and their anticancer applications

SIGNIFICANCE

Iron and topoisomerases are abundant and essential cellular components. Iron is required for several key processes such as DNA synthesis, mitochondrial electron transport, synthesis of heme, and as a co-factor for many redox enzymes. Topoisomerases serve as critical enzymes that resolve topological problems during DNA synthesis, transcription, and repair. Neoplastic cells have higher uptake and utilization of iron, as well as elevated levels of topoisomerase family members. Separately, the chelation of iron and the cytotoxic inhibition of topoisomerase have yielded potent anticancer agents.

RECENT ADVANCES

The chemotherapeutic drugs doxorubicin and dexrazoxane both chelate iron and target topoisomerase 2 alpha (top2α). Newer chelators such as di-2-pyridylketone-4,4,-dimethyl-3-thiosemicarbazone and thiosemicarbazone -24 have recently been identified as top2α inhibitors. The growing list of agents that appear to chelate iron and inhibit topoisomerases prompts the question of whether and how these two distinct mechanisms might interplay for a cytotoxic chemotherapeutic outcome.

CRITICAL ISSUES

While iron chelation and topoisomerase inhibition each represent mechanistically advantageous anticancer therapeutic strategies, dual targeting agents present an attractive multi-modal opportunity for enhanced anticancer tumor killing and overcoming drug resistance. The commonalities and caveats of dual inhibition are presented in this review.

FUTURE DIRECTIONS

Gaps in knowledge, relevant biomarkers, and strategies for future in vivo studies with dual inhibitors are discussed.

Cardiac response to doxorubicin and dexrazoxane in intact and ovariectomized young female rats at rest and after swim training

The impact of cancer therapies on adult cardiac function is becoming a concern as more children survive their initial cancer. Cardiovascular disease is now a significant problem to adult survivors of childhood cancer. Specifically, doxorubicin (DOX) may be particularly harmful in young girls. The objective of this study was to characterize DOX damage and determine the ability of dexrazoxane (DEX) to reduce DOX-mediated cardiac damage in sedentary and swim-trained female rats. Female Sprague-Dawley rats were left intact or ovariectomized (OVX) at weaning then injected with DEX (60 mg/kg) before DOX (3 mg/kg), DOX alone, or PBS. Rats were separated into sedentary and swim cohorts. Body weight was reduced in DOX:DEX- but not PBS- or DOX-treated rats. Echocardiographic parameters were similar in sedentary rats. Swim training revealed greater concentric remodeling in DOX-treated rats and reduced fractional shortening in DOX:DEX-treated rats. Calsequestrin 2 was reduced with DOX and increased with DOX:DEX postswim. Sarco(endo)plasmic reticulum Ca2+-ATPase 2a was reduced and calsequestrin 2 reduced further by swim training only in intact rats. OVX rats were heavier and developed eccentric remodeling post-swim with DOX and eccentric hypertrophy with DOX:DEX. Changes in SERCA2a and calsequestrin 2 expression were not observed. Ovariectomized DOX- and DOX:DEX-treated rats stopped growing during swim training. DEX coinjection did not relieve DOX-mediated cardiotoxicity in intact or hormone-deficient rats. DOX-mediated reductions in growth, cardiac function, and expression of calcium homeostasis proteins were exacerbated by swim. DEX coadministration did not substantially relieve DOX-mediated cardiotoxicity in young female rats. Ovarian hormones reduce DOX-induced cardiotoxicity.

Dexrazoxane for preventing anthracycline cardiotoxicity in children with solid tumors

This study attempted to assess the incidence and outcome of anthracycline cardiotoxicity and the role of dexrazoxane as a cardioprotectant in childhood solid tumors. The dexrazoxane group included 47 patients and the control group of historical cohort included 42. Dexrazoxane was given in the 10:1 ratio to doxorubicin. Fractional shortening and systolic and diastolic left ventricular diameters were used to assess the cardiac function. The median follow-ups were 54 months in the dexrazoxane group and 86 months in the control group. The mean cumulative doses of doxorubicin were 280.8+/-83.4 mg/m(2) in the dexrazoxane group and 266.1+/-75.0 mg/m(2) in the control group. The dexrazoxane group experienced significantly fewer cardiac events (27.7% vs. 52.4%) and less severe congestive heart failure (6.4% vs. 14.3%) than the control group. Thirteen cardiotoxicities including one cardiac death and 2 congestive heart failures occurred in the dexrazoxane group, and 22 cardiotoxicities including 2 cardiac deaths and 4 congestive heart failures, in the control group. Five year cardiac event free survival rates were 69.2% in the dexrazoxane group and 45.8% in the control group (P=0.04). Dexrazoxane reduces the incidence and severity of early and late anthracycline cardiotoxicity in childhood solid tumors.

Molecular pathogenetic mechanisms and new therapeutic perspectives in anthracycline-induced cardiomyopathy

Anthracyclines are among the most powerful drugs for the treatment of oncologic diseases both in childhood and in adulthood. Nevertheless, their major antineoplastic efficacy can be seriously impaired by collateral toxic cardiac effects causing cardiomyopathy with chronic heart failure that is refractory to conventional medical therapy.

This article reports possible subcellular molecular alterations of anthracycline-induced cardiomyopathy (reactive oxygen species formation, apoptosis, inflammatory signalling, altered expression of cardiomyocytes specific genes, etc) and indicates some new therapeutic perspectives resulting from a better understanding of the molecular pathogenetic mechanisms.

[Hodgkin's lymphoma in adolescents: where to treat it--in an adult or pediatric institution?]

Adolescent patients with Hodgkin's lymphoma (HL) are treated either in pediatric, or in adult oncological wards.

AIM

The aim of our work was to compare the treatment modalities and the survival rates in adolescents with HL treated in adult (A) or pediatric (P) institutes.

METHODS

From January 1990 to December 2004, 138 patients (14-21 years) with HL were treated in two adult institutes (A) and 107 in the 10 centres of the Hungarian Pediatric Oncology Network (P).

RESULTS

Male:female ratio was 1:1.15 (A) and 1:1.38 (P). The mean age was 18.6 (A) and 15.7 (P) years. There was no difference between the distribution of the stages in the two patient groups. The distribution of histological subtypes (A and P): nodular sclerosing 47% and 59%, mixed cellularity 45% and 25%, lymphocyte rich 1.5% and 10%, lymphocyte depleted 4% and 1%, nodular lymphocyte predominant 1.5% and 3% and unknown 1% and 2%. The majority of the patients were treated with ABVD (A) and OPPA/OEPA +/- COPP (P). One hundred and fifteen (A) and 97 (P) adolescents received irradiation therapy. 80% (A) and 91% (A) of the patients got radiotherapy. In group A 14%, in group P 13% of the patients had relapse. In group A 16 patients died and in group P 7. There was no significant difference in the overall survival (OS) rates at 5 and 10 years in the two patient groups. The event-free survival (EFS) was 76.5 +/- 4% and 72.5 +/- 4% at 5 and 10 years in group A, and 85.3 +/- 4% at both times in group P ( p = 0.0452).

CONCLUSION

Survival rates in HL are quite high, 80-90% of the patients can be cured. Event-free survival was higher in pediatric than in adult institutes. In case of patients younger than 18 years, the survival rates were much better in pediatric institutes, so these patients should be treated in pediatric institutes or with protocols used by the pediatricians.

[Lymphomas in adolescents: are childhood lymphoma therapy protocols suitable for this patient group?]

The centres of the Hungarian Paediatric Oncology Network annually take care of 250-300 new patients with childhood cancer, every tenth of them suffering from lymphoma. The aim of our work was to analyse the data of the adolescents (14-19 years) with Hodgkin's lymphoma (HL) and non-Hodgkin's lymphoma (NHL), comparing their survival rates with younger patients under fourteen and with the international data. From January 1990 to December 2004 there were 281 children diagnosed with HL and 230 with NHL. Among the HL patients 107, while among the NHL patients 51 were older than 14 years old. In the group of HL the distribution of patients according to the stage was similar in younger and older patients. In the NHL group 55% of the children younger than 14, and 72% of the patients older than 14 years old had advanced stage disease (stage III or IV). In both groups the patients received chemotherapy according to the current paediatric protocols. The overall survival (OS) of the HL patients younger than 14 was 92.5+/-2% at 5 years and 90.3+/-2% at 10 years, and for the adolescents 93.4+/-2% and 90.7+/-3% at 5 and 10 years (n.s.). The OS of the younger children in the NHL group was 78.2+/-3% at 5 and 10 years, and 77.9+/-6% for the adolescents (n.s.). As a conclusion, survival rates of the adolescents do not differ significantly from the parameters of the patients under fourteen, so the therapy protocols used for childhood lymphomas are suitable for the treatment of the lymphomas appearing at the age of 14-19 years.