Dexrazoxane and Long-Term Heart Function in Survivors of Childhood Cancer.

PURPOSE: For survivors of childhood cancer treated with doxorubicin, dexrazoxane is cardioprotective for at least 5 years. However, longer-term data are lacking. METHODS: Within the Children's Oncology Group and the Dana Farber Cancer Institute's Childhood Acute Lymphoblastic Leukemia Consortium, we evaluated four randomized trials of children with acute lymphoblastic leukemia or Hodgkin lymphoma, who received doxorubicin with or without dexrazoxane, and a nonrandomized trial of patients with osteosarcoma who all received doxorubicin with dexrazoxane. Cumulative doxorubicin doses ranged from 100 to 600 mg/m2 across these five trials, and dexrazoxane was administered uniformly (10:1 mg/m2 ratio) as an intravenous bolus before doxorubicin. Cardiac function was prospectively assessed in survivors from these trials, plus a matched group of survivors of osteosarcoma treated with doxorubicin without dexrazoxane. Two-dimensional echocardiograms and blood biomarkers were analyzed centrally in blinded fashion. Multivariate analyses adjusted for demographic characteristics, cumulative doxorubicin dose, and chest radiotherapy determined the differences and associations by dexrazoxane status. RESULTS: From 49 participating institutions, 195 participants were assessed at 18.1 ± 2.7 years since cancer diagnosis (51% dexrazoxane-exposed; cumulative doxorubicin dose 297 ± 91 mg/m2). Dexrazoxane administration was associated with superior left ventricular fractional shortening (absolute difference, +1.4% [95% CI, 0.3 to 2.5]) and ejection fraction (absolute difference, +1.6% [95% CI, 0.0 to 3.2]), and lower myocardial stress per B-type natriuretic peptide (-6.7 pg/mL [95% CI, -10.6 to -2.8]). Dexrazoxane was associated with a reduced risk of having lower left ventricular function (fractional shortening < 30% or ejection fraction < 50%; odds ratio, 0.24 [95% CI, 0.07 to 0.81]). This protective association was primarily seen in those treated with cumulative doxorubicin doses ≥ 250 mg/m2. CONCLUSION: Among young adult-aged survivors of childhood cancer, dexrazoxane was associated with a cardioprotective effect nearly 20 years after initial anthracycline exposure.

Dexrazoxane Alleviated Doxorubicin-Induced Nephropathy in Rats.

INTRODUCTION: Doxorubicin (DOX), an anthracycline antitumor agent, has been widely used against various solid tumors and hematological malignancies. However, the clinical application of DOX is restricted by its multiple organ toxicity including nephrotoxicity. This study investigated the protective effects and mechanisms of dexrazoxane (DZR) against DOX-induced nephropathy in rats. METHODS: Male Sprague Dawley rats received 2.5 mg/kg DOX once a week for 5 consecutive weeks. 24-h urinary protein and renal function injury biomarkers were determined to evaluate the renal function. Histopathological changes and glomerulosclerosis were examined by hematoxylin and eosin and periodic acid-Schiff staining. The change of renal ultrastructure in the DOX-induced rats was observed by the electron microscopy. The renal apoptosis was detected by TUNEL staining and measured the protein expression of Caspase-3, Bcl-2, and Bax. Renal interstitial fibrosis was determined by Masson staining and immunohistochemistry examination. The levels of vimentin, alpha-smooth muscle actin (α-SMA), and transforming growth factor ß (TGF-ß) in kidney tissue were detected by Western blot. RESULTS: DZR pretreatment markedly raised the survival rate and improved the renal dysfunction in DOX-treated rats. DZR ameliorated DOX-induced histopathological lesion of glomerular and tubular and apoptosis. DZR restored the oxidant/antioxidant balance via regulating the levels of MDA, SOD, and TAC. DZR reduced DOX-induced collagen IV deposition and renal interstitial fibrosis and downregulated the fibrosis-related protein expressions of vimentin, α-SMA, and TGF-ß1. CONCLUSION: Our results suggest DZR exerted its protective effects against DOX-induced nephropathy through inhibition of lipid peroxidation, apoptosis, and fibrosis.

Late health outcomes after dexrazoxane treatment: A report from the Children's Oncology Group.

BACKGROUND: The objective of this study was to examine long-term outcomes among children newly diagnosed with cancer who were treated in dexrazoxane-containing clinical trials. METHODS: P9404 (acute lymphoblastic leukemia/lymphoma [ALL]), P9425 and P9426 (Hodgkin lymphoma), P9754 (osteosarcoma), and Dana-Farber Cancer Institute 95-01 (ALL) enrolled 1308 patients between 1996 and 2001: 1066 were randomized (1:1) to doxorubicin with or without dexrazoxane, and 242 (from P9754) were nonrandomly assigned to receive dexrazoxane. Trial data were linked with the National Death Index, the Organ Procurement and Transplantation Network, the Pediatric Health Information System (PHIS), and Medicaid. Osteosarcoma survivors from the Childhood Cancer Survivor Study (CCSS; n = 495; no dexrazoxane) served as comparators in subanalyses. Follow-up events were assessed with cumulative incidence, Cox regression, and Fine-Gray methods. RESULTS: In randomized trials (cumulative prescribed doxorubicin dose, 100-360 mg/m2 ; median follow-up, 18.6 years), dexrazoxane was not associated with relapse (hazard ratio [HR], 0.84; 95% confidence interval [CI], 0.63-1.13), second cancers (HR, 1.19; 95% CI, 0.62-2.30), all-cause mortality (HR, 1.07; 95% CI, 0.78-1.47), or cardiovascular mortality (HR, 1.45; 95% CI, 0.41-5.16). Among P9754 patients (all exposed to dexrazoxane; cumulative doxorubicin, 450-600 mg/m2 ; median follow-up, 16.6-18.4 years), no cardiovascular deaths or heart transplantation occurred. The 20-year heart transplantation rate among CCSS osteosarcoma survivors (mean doxorubicin, 377 ± 145 mg/m2 ) was 1.6% (vs 0% in P9754; P = .13). Among randomized patients, serious cardiovascular outcomes (cardiomyopathy, ischemic heart disease, and stroke) ascertained by PHIS/Medicaid occurred less commonly with dexrazoxane (5.6%) than without it (17.6%; P = .02), although cardiomyopathy rates alone did not differ (4.4% vs 8.1%; P = .35). CONCLUSIONS: Dexrazoxane did not appear to adversely affect long-term mortality, event-free survival, or second cancer risk.

Minimizing cardiac toxicity in children with acute myeloid leukemia.

Anthracycline chemotherapy remains an integral component of modern pediatric acute myeloid leukemia (AML) regimens and is often delivered at high doses to maximize cancer survival. Unfortunately, high-dose anthracyclines are associated with a significant risk of cardiotoxicity, which may result in early and/or long-term left ventricular systolic dysfunction and heart failure. Moreover, the development of cardiotoxicity during pediatric AML therapy is associated with lower event-free and overall survival, which may be partially attributable to incomplete anthracycline delivery. A combined strategy of primary cardioprotection and close cardiac monitoring can maximize chemotherapy delivery while reducing the toxicity of intensive AML therapy. Primary cardioprotection using dexrazoxane reduces short-term cardiotoxicity without compromising cancer survival. Liposomal anthracycline formulations, which are under active investigation, have the potential to mitigate cardiotoxicity while also improving antitumor efficacy. Primary cardioprotective strategies may reduce but not eliminate the risk of cardiotoxicity; therefore, close cardiac monitoring is also needed. Standard cardiac monitoring consists of serial echocardiographic assessments for left ventricular ejection fraction decline. Global longitudinal strain has prognostic utility in cancer therapy-related cardiotoxicity and may be used as an adjunct assessment. Additional cardioprotective measures should be considered in response to significant cardiotoxicity; these include cardiac remodeling medications to support cardiac recovery and anthracycline dose interruption and/or regimen modifications. However, the withholding of anthracyclines should be limited to avoid compromising cancer survival. A careful approach to cardioprotection during AML therapy is critical to maximize the efficacy of leukemia treatment while minimizing the short- and long-term risks of cardiotoxicity.

Clinically Translatable Prevention of Anthracycline Cardiotoxicity by Dexrazoxane Is Mediated by Topoisomerase II Beta and Not Metal Chelation.

BACKGROUND: Anthracycline-induced heart failure has been traditionally attributed to direct iron-catalyzed oxidative damage. Dexrazoxane (DEX)-the only drug approved for its prevention-has been believed to protect the heart via its iron-chelating metabolite ADR-925. However, direct evidence is lacking, and recently proposed TOP2B (topoisomerase II beta) hypothesis challenged the original concept. METHODS: Pharmacokinetically guided study of the cardioprotective effects of clinically used DEX and its chelating metabolite ADR-925 (administered exogenously) was performed together with mechanistic experiments. The cardiotoxicity was induced by daunorubicin in neonatal ventricular cardiomyocytes in vitro and in a chronic rabbit model in vivo (n=50). RESULTS: Intracellular concentrations of ADR-925 in neonatal ventricular cardiomyocytes and rabbit hearts after treatment with exogenous ADR-925 were similar or exceeded those observed after treatment with the parent DEX. However, ADR-925 did not protect neonatal ventricular cardiomyocytes against anthracycline toxicity, whereas DEX exhibited significant protective effects (10-100 µmol/L; P<0.001). Unlike DEX, ADR-925 also had no significant impact on daunorubicin-induced mortality, blood congestion, and biochemical and functional markers of cardiac dysfunction in vivo (eg, end point left ventricular fractional shortening was 32.3±14.7%, 33.5±4.8%, 42.7±1.0%, and 41.5±1.1% for the daunorubicin, ADR-925 [120 mg/kg]+daunorubicin, DEX [60 mg/kg]+daunorubicin, and control groups, respectively; P<0.05). DEX, but not ADR-925, inhibited and depleted TOP2B and prevented daunorubicin-induced genotoxic damage. TOP2B dependency of the cardioprotective effects was probed and supported by experiments with diastereomers of a new DEX derivative. CONCLUSIONS: This study strongly supports a new mechanistic paradigm that attributes clinically effective cardioprotection against anthracycline cardiotoxicity to interactions with TOP2B but not metal chelation and protection against direct oxidative damage.

Extravasation accidents with liposomal/liposomal pegylated anthracyclines treated with dexrazoxane: an overview and outcomes.

The extravasation of chemotherapeutic agents is a challenge for oncologic care teams. The management of nonliposomal (conventional) anthracyclines is well established in clinical practice guidelines, including general measures and specific antidotes, such as dexrazoxane. However, there is little scientific evidence on the management of liposomal and pegylated liposomal anthracyclines. The aim of this paper was to review the scientific literature on the extravasation of liposomal and pegylated liposomal anthracyclines and determine the clinical impact of this type of extravasation, focusing on dexrazoxane. The literature was searched using two databases: PubMed and Embase. Three searches were conducted, using liposomal anthracycline extravasation, pegylated liposomal anthracycline extravasation, and liposomal doxorubicin extravasation as keywords, respectively. Seven articles fulfilled the study eligibility criteria and included seventeen cases in humans. Extravasation occurred with three drugs: liposomal doxorubicin in nine (53%) patients, liposomal daunorubicin in four (23.5%) patients, and pegylated liposomal doxorubicin in four (23.5%) patients. General measures for extravasations were applied in all patients, but only three patients received dexrazoxane. All cases were completely resolved at 2-3 months, except for one patient, in whom dexrazoxane was not used. In animals, dexrazoxane decreased both the frequency of wounds produced by pegylated liposomal doxorubicin and their extent. The pharmacokinetic profiles of liposomal and pegylated liposomal anthracyclines differ from those of conventional anthracyclines, modifying their effectiveness and safety. General measures may be inadequate to heal areas affected by extravasation, which may require the administration of dexrazoxane. However, each case should be evaluated individually for the administration of dexrazoxane in off-label use until scientific evidence is available on its effectiveness and safety as an antidote for these formulations of anthracyclines.

Risk-benefit of dexrazoxane for preventing anthracycline-related cardiotoxicity: re-evaluating the European labeling.

Dexrazoxane can prevent anthracycline-associated cardiotoxicity. However, in 2011, its use in children was contraindicated by the EMA over concerns of increased risk of infection, myelosuppression and second primary malignancies, and because its efficacy in children had not then been established. We review here the evidence published since 2011, which confirms that dexrazoxane is an effective cardioprotectant in children and adolescents, is not associated with an increased risk of second primary malignancies or excess early or late mortality and does not impair chemotherapy efficacy. Based on this evidence, the contraindication for children and adolescents requiring high doses of anthracyclines and at risk for cardiotoxicity was removed from the European labeling for dexrazoxane.

Dexrazoxane Significantly Reduces Anthracycline-induced Cardiotoxicity in Pediatric Solid Tumor Patients: A Systematic Review.

Cardiotoxicity is a dose-limiting and potentially lethal complication of anthracycline administration. Previous studies failed to determine definitive toxic doses or cardioprotective factors. Current dosing strategies may utilize unnecessarily high anthracycline doses, such that survival benefit may not outweigh increased toxicity rates. A systematic review of randomized controlled trials and prospective/retrospective studies investigating anthracycline treatment in pediatric solid tumors was performed from PubMed/MEDLINE and Cochrane databases. Generalized linear models mapping survival, cardiotoxicity, and cardiotoxicity-free survival adjusted for male-to-female ratio, follow-up time, and concomitant chemotherapeutic drugs or cardioprotective agents (dexrazoxane) were generated using R. Survival rose linearly with increasing cumulative anthracycline dose whereas cardiotoxicity demonstrated exponential increases both without (dose, >200 mg/m) and with (dose, >400 mg/m) dexrazoxane. Maximum cardiotoxicity-free survival was 268.2 mg/m without and 431.8 mg/m with dexrazoxane. Despite increasing cardiotoxicity-free dose by >150 mg/m, dexrazoxane minimally improved projected survival (71.9% vs. 75.4%). Cardiotoxicity increased linearly as a function of follow-up time with rates doubling from 5 to 20 years, without evidence of plateau. On the basis of our model, current dosing regimens-doxorubicin doses >375 mg/m without dexrazoxane-overvalue increased anthracycline administration and may contribute to devastating cardiotoxicity. The linear increase of cardiotoxicity without evidence of plateau confirms the necessity for lifelong cardiac monitoring.

Dexrazoxane added to doxorubicin-based adjuvant chemotherapy of breast cancer: a retrospective cohort study with a comparative analysis of toxicity and survival.

Dexrazoxane is indicated as a cardioprotective agent for patients receiving doxorubicin who are at increased risk for cardiotoxicity. Concerns have been raised on the use of dexrazoxane, particularly in adjuvant therapy, because of the risk of interference with the antitumor effect of doxorubicin. Two meta-analyses in metastatic breast cancer have rejected this hypothesis, but have shown an apparent increase in the severity of myelosuppression when dexrazoxane is used. Here, we analyzed retrospectively a cohort of our institute database to assess whether the addition of dexrazoxane causes more bone marrow suppression in breast cancer patients receiving doxorubicin-based adjuvant therapy. The secondary objectives were assessment of the incidence of febrile neutropenia, dose-schedule modifications, recorded cardiac events or cardiac test abnormalities, and overall survival. Eight hundred and twenty-two female patients who received adjuvant (or neoadjuvant) doxorubicin and cyclophosphamide for breast cancer between 2001 and 2013 were included. One hundred and four of these patients also received dexrazoxane concurrently with the adjuvant treatment. Hospital records and, when accessible, community clinic records were reviewed. The median follow-up duration was 7 years for patients receiving dexrazoxane and 7.5 years for patients not receiving dexrazoxane. 85.6% of patients were alive at data lock. Compared with the nondexrazoxane group, patients who received dexrazoxane were older (median age at diagnosis 59 vs. 52 years) and more likely to receive dose-dense AC therapy (73 vs. 59%) and adjuvant trastuzumab treatment (29 vs. 15%). Compared with the nondexrazoxane group, dexrazoxane treatment was associated with a higher rate of hematological side effects: leukopenia (48 vs. 39%), neutropenia (45 vs. 31%, P=0.003), anemia (86 vs. 73%, P=0.005), and thrombocytopenia (37 vs. 22%, P=0.001). There were more febrile neutropenia hospitalizations (20 vs. 10%, P=0.001) and dose reductions (22 vs. 8%, P<0.001) in the dexrazoxane group, but no significant difference in the incidence of treatment delays or cancellations. The incidence of cardiac events was the same in both treatment groups with and without dexrazoxane. There was a nonsignificantly lower mortality rate in the dexrazoxane group (9.6%) compared with the nondexrazoxane group (15.0%) at data lock. Adding dexrazoxane to doxorubicin in adjuvant therapy patients leads to higher rates of bone marrow suppression in all blood components, as well as more febrile neutropenia events, and dose reductions. No differences in events defined as cardiac toxicities were detected. Dexrazoxane had no detrimental effect on survival, despite the higher hematological toxicity, the older median age, and the higher prevalence of HER2-positive disease in the dexrazoxane group.

Cardioprotection and Second Malignant Neoplasms Associated With Dexrazoxane in Children Receiving Anthracycline Chemotherapy: A Systematic Review and Meta-Analysis.

BACKGROUND: Several randomized controlled trials (RCTs) have demonstrated that dexrazoxane reduces anthracycline cardiotoxicity in adults, but use in children has been hindered by lack of direct evidence of cardioprotection and concerns regarding second malignant neoplasms (SMNs). This study aimed to systematically review the evidence regarding dexrazoxane in children. METHODS: We searched Medline, Embase, the Cochrane Library, and abstracts for RCTs and nonrandomized studies (NRSs) that compared dexrazoxane to no cardioprotection among children. We combined findings using random-effects models. All statistical tests were two-sided. RESULTS: Eleven eligible publications reported results from five RCTs (1254 patients), and 15 publications reported results from 12 NRSs (3385 patients). Dexrazoxane did not impact clinical cardiotoxicity in RCTs because of a low cardiotoxic event rate (three events among all patients) but was associated with a reduction in subclinical cardiotoxicity. Among NRSs, dexrazoxane was associated with a reduction in clinical cardiotoxicity (relative risk (RR) = 0.29, P = .001) and clinical+subclinical cardiotoxicity (RR = 0.43, P < .001). Among RCTs, 17 of 635 (2.7%) patients treated with dexrazoxane developed an SMN compared with seven of 619 (1.1%) who did not receive dexrazoxane (RR = 2.37, P = .06). Two RCTs that used concurrent etoposide reported an increased risk of acute myeloid leukemia, while one that used cranial radiation reported an increased risk of brain tumors. Event-free survival did not differ (P = .91). CONCLUSION: Dexrazoxane is associated with a statistically significant risk reduction for most cardiotoxic outcomes. Dexrazoxane is associated with a statistically borderline increase in SMNs, possibly because of an interaction with concurrent cancer therapies. The decision to use dexrazoxane in children should balance the risks of cardiotoxicity and SMNs specific to each treatment protocol.

Late Mortality After Dexrazoxane Treatment: A Report From the Children's Oncology Group.

PURPOSE: Given concerns that dexrazoxane may reduce treatment efficacy, induce second cancers, and thus compromise overall survival among children, we examined long-term overall and cause-specific mortality and disease relapse rates from three randomized clinical trials. PATIENTS AND METHODS: Children's Oncology Group trials P9404 (T-cell acute lymphoblastic leukemia/lymphoma; n = 537), P9425 (intermediate/high-risk Hodgkin lymphoma; n = 216), and P9426 (low-risk Hodgkin lymphoma; n = 255) were conducted between 1996 and 2001. Each trial randomly assigned patients to doxorubicin with or without dexrazoxane. The dexrazoxane:doxorubicin dose ratio was 10:1, and the cumulative protocol-specified doxorubicin dose was 100 to 360 mg/m(2). Dexrazoxane was given as an intravenous bolus before each doxorubicin dose. Data from all three trials were linked with the National Death Index to determine overall and cause-specific mortality by dexrazoxane status. RESULTS: Among 1,008 patients (507 received dexrazoxane) with a median follow-up of 12.6 years (range, 0 to 15.5 years), 132 died (67 received dexrazoxane). Overall mortality did not vary by dexrazoxane status (12.8% with dexrazoxane at 10 years v 12.2% without; hazard ratio [HR], 1.03; 95% CI, 0.73 to 1.45). Findings were similar when each trial was examined separately. Dexrazoxane also was not significantly associated with differential causes of death. The original cancer caused 76.5% of all deaths (HR, 0.90; 95% CI, 0.61 to 1.32) followed by second cancers (13.6% of deaths; HR, 1.24; 95% CI, 0.49 to 3.15). Specifically, dexrazoxane was not associated with deaths from acute myeloid leukemia/myelodysplasia or cardiovascular events. CONCLUSION: Among pediatric patients with leukemia or lymphoma, after extended follow-up, dexrazoxane use did not seem to compromise long-term survival.

Dexrazoxane exposure and risk of secondary acute myeloid leukemia in pediatric oncology patients.

BACKGROUND: Dexrazoxane may reduce anthracycline-associated cardiotoxicity in pediatric cancer patients. However, concerns of secondary acute myeloid leukemia (AML) have led to restrictions on pediatric dexrazoxane use in Europe. Published data about dexrazoxane-associated secondary AML are limited and conflicting. We sought to estimate the secondary AML risk in children receiving dexrazoxane after anthracycline exposure. PROCEDURE: A retrospective cohort of children with newly identified malignancies (excluding AML) receiving anthracyclines between January 1, 1999 and March 31, 2011 was established using the Pediatric Health Information System (PHIS). Patients were followed for all subsequent admissions to identify dexrazoxane exposures and secondary AML, defined by AML ICD-9 codes and AML induction chemotherapy. Logistic regression was used to model the association of dexrazoxane and secondary AML risk. A propensity score was used to adjust for measurable confounding. RESULTS: Of 15,532 patients in the cohort exposed to anthracyclines, 1,406 received dexrazoxane. The secondary AML rate was 0.21% (3 of 1,046) in dexrazoxane-exposed and 0.55% (77 of 14,126) in unexposed patients. In a propensity score-adjusted multivariate analysis, dexrazoxane exposure was not associated with an increased risk of secondary AML, OR = 0.38, 95% CI 0.11-1.26. CONCLUSIONS: Dexrazoxane was not associated with an increased risk of secondary AML in a large cohort of pediatric cancer patients receiving anthracyclines in US hospitals. While these data support dexrazoxane's safety in the general pediatric oncology population, additional studies are needed to confirm these findings and to quantify dexrazoxane's long-term cardioprotective effects.