What is the place of carboplatin in paediatric oncology?

Alkylating agents-induced gonadotoxicity in prepubertal males: Insights on the clinical and preclinical front

Rising cure rates in pediatric cancer patients warrants an increased attention toward the long-term consequences of the diagnosis and treatment in survivors. Chemotherapeutic agents can be gonadotoxic, rendering them at risk for infertility post-survival. While semen cryopreservation is an option that can be provided for most (post)pubertal boys before treatment, this is unfortunately not an option prepubertal in age, simply due to the lack of spermatogenesis. Over the last couple of years, studies have thus focused on better understanding the testis niche in response to various chemotherapeutic agents that are commonly administered and their direct and indirect impact on the germ cell populations. These are generally compounds that have a high risk of infertility and have been classified into risk categories in curated fertility guidelines. However, with it comes the lack of evidence and the challenge of using informative models and conditions most reflective of the physiological scenario, in short, the appropriate study designs for clinically relevant outcomes. Besides, the exact mechanism(s) of action for many of these "risk" compounds as well as other agents is unclear. Understanding their behavior and effect on the testis niche will pave the way for incorporating new strategies to ultimately combat infertility. Of the various drug classes, alkylating agents pose the highest risk of gonadotoxicity as per previously established studies as well as risk stratification guidelines. Therefore, this review will summarize the findings in the field of male fertility concerning gonadotoxicity of akylating agents as a result of chemotherapy exposure.

SIOP PNET5 MB Trial: History and Concept of a Molecularly Stratified Clinical Trial of Risk-Adapted Therapies for Standard-Risk Medulloblastoma

BACKGROUND

SIOP PNET5 MB was initiated in 2014 as the first European trial using clinical, histological, and molecular parameters to stratify treatments for children and adolescents with standard-risk medulloblastoma.

METHODS

Stratification by upfront assessment of molecular parameters requires the timely submission of adequate tumour tissue. In the standard-risk phase-III cohort, defined by the absence of high-risk criteria (M0, R0), pathological (non-LCA), and molecular biomarkers (MYCN amplification in SHH-MB or MYC amplification), a randomized intensification by carboplatin concomitant with radiotherapy is investigated. In the LR stratum for localized WNT-activated medulloblastoma and age <16 years, a reduction of craniospinal radiotherapy dose to 18 Gy and a reduced maintenance chemotherapy are investigated. Two additional strata (WNT-HR, SHH-TP53) were implemented during the trial.

RESULTS

SIOP PNET5 MB is actively recruiting. The availability of adequate tumour tissue for upfront real-time biological assessments to assess inclusion criteria has proven feasible.

CONCLUSION

SIOP PNET5 MB has demonstrated that implementation of biological parameters for stratification is feasible in a prospective multicentre setting, and may improve risk-adapted treatment. Comprehensive research studies may allow assessment of additional parameters, e.g., novel medulloblastoma subtypes, and identification and validation of biomarkers for the further refinement of risk-adapted treatment in the future.

Carboplatin Dosing in Children Using Estimated Glomerular Filtration Rate: Equation Matters

Renal function-based carboplatin dosing using measured glomerular filtration rate (GFR) results in more consistent drug exposure than anthropometric dosing. We aimed to validate the Newell dosing equation using estimated GFR (eGFR) and study which equation most accurately predicts carboplatin clearance in children with retinoblastoma. In 13 children with retinoblastoma 38 carboplatin clearance values were obtained from individual fits using MWPharm++. Carboplatin exposure (AUC) was calculated from administered dose and observed carboplatin clearance and compared to predicted AUC calculated with a carboplatin dosing equation (Newell) using different GFR estimates. Different dosing regimens were compared in terms of accuracy, bias and precision. All patients had normal eGFR. Carboplatin exposure using cystatin C-based eGFR equations tended to be more accurate compared to creatinine-based eGFR (30% accuracy 76.3-89.5% versus 76.3-78.9%, respectively), which led to significant overexposure, especially in younger (aged ≤ 2 years) children. Of all equations, the Schwartz cystatin C-based equation had the highest accuracy and lowest bias. Although anthropometric dosing performed comparably to many of the eGFR equations overall, we observed a weight-dependent change in bias leading to underdosing in the smallest patients. Using cystatin C-based eGFR equations for carboplatin dosing in children leads to more accurate carboplatin-exposure in patients with normal renal function compared to anthropometric dosing. In children with impaired kidney function, this trend might be more pronounced. Anthropometric dosing is hampered by a weight-dependent bias.

Combination Therapy of Cisplatin and other Agents for Osteosarcoma: A Review

Background:

Osteosarcoma is the most common type of primary bone tumor in children and adolescents, which is associated with rapid progression and poor prognosis. Multimodal therapy is the most common approach utilized for osteosarcoma management, such as the application of chemotherapy in combination with surgery or radiation therapy. Cisplatin is one of the predominantly used chemotherapeutic agents for osteosarcoma. Optimally, it is employed in combination with other chemotherapeutic drugs along with surgery or radiation therapy. Despite the availability of numerous treatment approaches, the patient survival rate has not definitively improved over the past three decades.

Methods:

We have summarized all findings regarding the combination of cisplatin with other chemotherapeutic agents as well as with phytochemical compounds.

Results:

A combination of cisplatin with a phytochemical compound synergistically enhances the killing effect of cisplatin on osteosarcoma cells with fewer side effects compared to combination with other chemotherapeutic agents.

Conclusion:

Conclusively, a combination of cisplatin with selected chemotherapeutic drugs has been shown to be effective. However, the unchanged survival rate has posed an urge to search for a new combination regimen. As a collaborative effort to substantiate the therapeutic efficacy, the combination with phytochemical compounds shows a promising response both in vitro as well as in the preclinical study.

Early and late adverse renal effects after potentially nephrotoxic treatment for childhood cancer

BACKGROUND

Improvements in diagnostics and treatment for paediatric malignancies resulted in a major increase in survival. However, childhood cancer survivors (CCS) are at risk of developing adverse effects caused by multimodal treatment for their malignancy. Nephrotoxicity is a known side effect of several treatments, including cisplatin, carboplatin, ifosfamide, radiotherapy and nephrectomy, and can cause glomerular filtration rate (GFR) impairment, proteinuria, tubulopathy, and hypertension. Evidence about the long-term effects of these treatments on renal function remains inconclusive. It is important to know the risk of, and risk factors for, early and late adverse renal effects, so that ultimately treatment and screening protocols can be adjusted. This review is an update of a previously published Cochrane Review.

OBJECTIVES

To evaluate existing evidence on the effects of potentially nephrotoxic treatment modalities on the prevalence of renal dysfunction in survivors treated for childhood cancer with a median or mean survival of at least one year after cessation of treatment, where possible in comparison with the general population or CCS treated without potentially nephrotoxic treatment. In addition, to evaluate evidence on associated risk factors, such as follow-up duration, age at time of diagnosis and treatment combinations, as well as the effect of doses.

SEARCH METHODS

On 31 March 2017 we searched the following electronic databases: CENTRAL, MEDLINE and Embase. In addition, we screened reference lists of relevant studies and we searched the congress proceedings of the International Society of Pediatric Oncology (SIOP) and The American Society of Pediatric Hematology/Oncology (ASPHO) from 2010 to 2016/2017.

SELECTION CRITERIA

Except for case reports, case series and studies including fewer than 20 participants, we included studies with all study designs that reported on renal function (one year or longer after cessation of treatment), in CCS treated before the age of 21 years with cisplatin, carboplatin, ifosfamide, radiation involving the kidney region, a nephrectomy, or a combination of two or more of these treatments. When not all treatment modalities were described or the study group of interest was unclear, a study was not eligible for the evaluation of prevalence. We still included it for the assessment of risk factors if it had performed a multivariable analysis.

DATA COLLECTION AND ANALYSIS

Two review authors independently performed study selection, 'Risk of bias' assessment and data extraction using standardised data collection forms. We performed analyses according to the guidelines of the Cochrane Handbook for Systematic Reviews of Interventions.

MAIN RESULTS

Apart from the remaining 37 studies included from the original review, the search resulted in the inclusion of 24 new studies. In total, we included 61 studies; 46 for prevalence, six for both prevalence and risk factors, and nine not meeting the inclusion criteria, but assessing risk factors. The 52 studies evaluating the prevalence of renal dysfunction included 13,327 participants of interest, of whom at least 4499 underwent renal function testing. The prevalence of adverse renal effects ranged from 0% to 84%. This variation may be due to diversity of included malignancies, received treatments, reported outcome measures, follow-up duration and the methodological quality of available evidence.Seven out of 52 studies, including 244 participants, reported the prevalence of chronic kidney disease, which ranged from 2.4% to 32%.Of these 52 studies, 36 studied a decreased (estimated) GFR, including at least 432 CCS, and found it was present in 0% to 73.7% of participants. One eligible study reported an increased risk of glomerular dysfunction after concomitant treatment with aminoglycosides and vancomycin in CCS receiving total body irradiation (TBI). Four non-eligible studies assessing a total cohort of CCS, found nephrectomy and (high-dose (HD)) ifosfamide as risk factors for decreased GFR. The majority also reported cisplatin as a risk factor. In addition, two non-eligible studies showed an association of a longer follow-up period with glomerular dysfunction.Twenty-two out of 52 studies, including 851 participants, studied proteinuria, which was present in 3.5% to 84% of participants. Risk factors, analysed by three non-eligible studies, included HD cisplatin, (HD) ifosfamide, TBI, and a combination of nephrectomy and abdominal radiotherapy. However, studies were contradictory and incomparable.Eleven out of 52 studies assessed hypophosphataemia or tubular phosphate reabsorption (TPR), or both. Prevalence ranged between 0% and 36.8% for hypophosphataemia in 287 participants, and from 0% to 62.5% for impaired TPR in 246 participants. One non-eligible study investigated risk factors for hypophosphataemia, but could not find any association.Four out of 52 studies, including 128 CCS, assessed the prevalence of hypomagnesaemia, which ranged between 13.2% and 28.6%. Both non-eligible studies investigating risk factors identified cisplatin as a risk factor. Carboplatin, nephrectomy and follow-up time were other reported risk factors.The prevalence of hypertension ranged from 0% to 50% in 2464 participants (30/52 studies). Risk factors reported by one eligible study were older age at screening and abdominal radiotherapy. A non-eligible study also found long follow-up time as risk factor. Three non-eligible studies showed that a higher body mass index increased the risk of hypertension. Treatment-related risk factors were abdominal radiotherapy and TBI, but studies were inconsistent.Because of the profound heterogeneity of the studies, it was not possible to perform meta-analyses. Risk of bias was present in all studies.

AUTHORS' CONCLUSIONS

The prevalence of adverse renal effects after treatment with cisplatin, carboplatin, ifosfamide, radiation therapy involving the kidney region, nephrectomy, or any combination of these, ranged from 0% to 84% depending on the study population, received treatment combination, reported outcome measure, follow-up duration and methodological quality. With currently available evidence, it was not possible to draw solid conclusions regarding the prevalence of, and treatment-related risk factors for, specific adverse renal effects. Future studies should focus on adequate study designs and reporting, including large prospective cohort studies with adequate control groups when possible. In addition, these studies should deploy multivariable risk factor analyses to correct for possible confounding. Next to research concerning known nephrotoxic therapies, exploring nephrotoxicity after new therapeutic agents is advised for future studies. Until more evidence becomes available, CCS should preferably be enrolled into long-term follow-up programmes to monitor their renal function and blood pressure.

Selenium action in neuro-oncology

The trace element selenium and selenocysteine-carrying selenoproteins play a pivotal role in the brain. Beside the essential function during development and maintenance of brain action, selenium has also been associated with several neurological and neuro-oncological conditions. Reliable supply of selenium is important since selenium compounds can affect tumor microenvironment and neoangiogenesis in malignant gliomas (WHO grade III and IV [glioblastoma, GBM]) via induction of apoptosis and alteration of matrix metalloproteinases expression. Here, we summarize recent findings focusing on the anti-toxicity and cancer-preventive properties of selenium and their implication in current multimodal therapies including temozolomide (Temodal), cyclophosphamide (Endoxan), and cisplatin (DDP, Platiblastin, and Platinol). We shed light on unintended side effects in chemotherapy and the developments of novel combinatorial chemotherapeutics with selenium compounds. We found that selenium and selenium compounds have dual action profiles with direct anti-cancer and chemotherapy-intensifier effects as well as neuroprotective and cytoprotective agents. Current selenium trials and selenium supplementation with focus on neuro-oncology will be discussed with regard to low-adequate-to-high/toxic selenium status.

Early and late renal adverse effects after potentially nephrotoxic treatment for childhood cancer

BACKGROUND

Great improvements in diagnostics and treatment for malignant disease in childhood have led to a major increase in survival. However, childhood cancer survivors (CCS) are at great risk for developing adverse effects caused by multimodal treatment for their malignancy. Nephrotoxicity is one of these known (acute) side effects of several treatments, including cisplatin, carboplatin, ifosfamide, radiotherapy and nephrectomy, and can cause glomerular filtration rate impairment, proteinuria, tubulopathy and hypertension. However, evidence about the long-term effects of these treatments on renal function remains inconclusive. To reduce the number of (long-term) nephrotoxic events in CCS, it is important to know the risk of, and risk factors for, early and late renal adverse effects, so that ultimately treatment and screening protocols can be adjusted.

OBJECTIVES

To evaluate existing evidence on the effects of potentially nephrotoxic treatment modalities on the prevalence of and associated risk factors for renal dysfunction in survivors treated for childhood cancer with a median or mean survival of at least one year after cessation of treatment, where possible in comparison with healthy controls or CCS treated without potentially nephrotoxic treatment.

SEARCH METHODS

We searched the following electronic databases: the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, Issue 4, 2011), MEDLINE/PubMed (from 1945 to December 2011) and EMBASE/Ovid (from 1980 to December 2011).

SELECTION CRITERIA

With the exception of case reports, case series and studies including fewer than 20 participants, we included studies with all study designs that reported on renal function (one year or longer after cessation of treatment) in children and adults who were treated for a paediatric malignancy (aged 18 years or younger at diagnosis) with cisplatin, carboplatin, ifosfamide, radiation including the kidney region and/or a nephrectomy.

DATA COLLECTION AND ANALYSIS

Two review authors independently performed study selection, risk of bias assessment and data extraction using standardised data collection forms. Analyses were performed according to the guidelines of the Cochrane Handbook for Systematic Reviews of Interventions.

MAIN RESULTS

The search strategy identified 5504 studies, of which 5138 were excluded on the basis of title and/or abstract. The full-text screening of the remaining 366 articles resulted in the inclusion of 57 studies investigating the prevalence of and sometimes also risk factors for early and late renal adverse effects of treatment for childhood cancer. The 57 studies included at least 13,338 participants of interest for this study, of whom at least 6516 underwent renal function testing. The prevalence of renal adverse effects ranged from 0% to 84%. This variation may be due to diversity in included malignancies, prescribed treatments, reported outcome measurements and the methodological quality of available evidence.Chronic kidney disease/renal insufficiency (as defined by the authors of the original studies) was reported in 10 of 57 studies. The prevalence of chronic kidney disease ranged between 0.5% and 70.4% in the 10 studies and between 0.5% and 18.8% in the six studies that specifically investigated Wilms' tumour survivors treated with a unilateral nephrectomy.A decreased (estimated) glomerular filtration rate was present in 0% to 50% of all assessed survivors (32/57 studies). Total body irradiation; concomitant treatment with aminoglycosides, vancomycin, amphotericin B or cyclosporin A; older age at treatment and longer interval from therapy to follow-up were significant risk factors reported in multivariate analyses. Proteinuria was present in 0% to 84% of all survivors (17/57 studies). No study performed multivariate analysis to assess risk factors for proteinuria.Hypophosphataemia was assessed in seven studies. Reported prevalences ranged between 0% and 47.6%, but four of seven studies found a prevalence of 0%. No studies assessed risk factors for hypophosphataemia using multivariate analysis. The prevalence of impairment of tubular phosphate reabsorption was mostly higher (range 0% to 62.5%; 11/57 studies). Higher cumulative ifosfamide dose, concomitant cisplatin treatment, nephrectomy and longer follow-up duration were significant risk factors for impaired tubular phosphate reabsorption in multivariate analyses.Treatment with cisplatin and carboplatin was associated with a significantly lower serum magnesium level in multivariate analysis, and the prevalence of hypomagnesaemia ranged between 0% and 37.5% in the eight studies investigating serum magnesium.Hypertension was investigated in 24 of the 57 studies. Reported prevalences ranged from 0% to 18.2%. A higher body mass index was the only significant risk factor noted in more than one multivariate analysis. Other reported factors that significantly increased the risk of hypertension were use of total body irradiation, abdominal irradiation, acute kidney injury, unrelated or autologous stem cell donor type, growth hormone therapy and older age at screening. Previous infection with hepatitis C significantly decreased the risk of hypertension.Because of the profound heterogeneity of the studies, it was not possible to perform any meta-analysis.

AUTHORS' CONCLUSIONS

The prevalence of renal adverse events after treatment with cisplatin, carboplatin, ifosfamide, radiation therapy involving the kidney region and/or nephrectomy ranged from 0% to 84%. With currently available evidence, it was not possible to draw any conclusions with regard to prevalence of and risk factors for renal adverse effects. Future studies should focus on adequate study design and reporting and should deploy multivariate risk factor analysis to correct for possible confounding. Until more evidence becomes available, CCS should be enrolled into long-term follow-up programmes to monitor their renal function and blood pressure.

Antineoplastic drug, carboplatin, protects mice against visceral leishmaniasis

In the present study, the leishmanicidal effect of two doses (5 and 10 mg/kg body weight) of the carboplatin was studied in Leishmania donovani-infected BALB/c mice. Mice were infected intracardially with promastigotes of L. donovani, and a month after infection, they were treated intraperitoneally with the two doses of the drug (5 and 10 mg/kg body weight) for five continuous days. Animals were sacrificed on 1 and 15 posttreatment days. Hepatic parasite load was assessed on Geimsa-stained imprints. Immune responses were studied by measuring delayed-type hypersensitivity (DTH) responses, serum IgG isotype levels (IgG1 and IgG2a) and cytokine levels [γ-interferon (IFN-γ), interleukin (IL)-10 and IL-2] in spleen cell cultures by ELISA. To study the drug-induced side effects, various haematological (haemoglobin and total leukocyte count), biochemical (liver and kidney function tests) and histological investigations (kidney, liver and spleen) were carried out. The antileishmanial potential of the drug was revealed by significant reduction in the parasite burden. The infected and treated animals were also found to exhibit increased DTH responses, higher IgG2a levels, lower IgG1 levels and greater cytokine (IFN-γ, IL-10 and IL-2) concentrations pointing towards the generation of mixed Th1/Th2 response. Liver and kidney function tests and histological studies of kidney, liver and spleen of treated mice revealed no side effects. Carboplatin cures mice of visceral leishmaniasis without causing any serious side effects, and the drug was found be more effective at a dose of 10 mg/kg body weight as compared to 5 mg/kg body weight.

Novel retinoblastoma treatment avoids chemotherapy: the effect of optimally timed combination therapy with angiogenic and glycolytic inhibitors on LH(BETA)T(AG) retinoblastoma tumors

PURPOSE

The purpose of this study was to evaluate the effect of optimally timed combination treatment with angiogenic and glycolytic inhibitors on tumor burden, hypoxia, and angiogenesis in advanced retinoblastoma tumors.

METHODS

LH(BETA)T(AG) mice (n =30) were evaluated. Mice were divided into 5 groups (n =6) and received injections at 16 weeks of age (advanced tumors) with a) saline, b) anecortave acetate (AA), c) 2-deoxyglucose (2-DG), d) AA +2-DG (1 day post-AA treatment), or e) AA +2-DG (1 week post-AA treatment). Eyes were enucleated at 21 weeks and tumor sections were analyzed for hypoxia, angiogenesis, and tumor burden.

RESULTS

Eyes treated with 2-DG 1 day post-AA injection showed a 23% (P =0.03) reduction in tumor burden compared with 2-DG alone and a 61% (P < 0.001) reduction compared with saline-treated eyes. Eyes treated with 2-DG 1 week post-AA injection showed no significant decrease in tumor burden compared with 2-DG alone (P = 0.21) and a 56% (P < 0.001) decrease in comparison with saline-treated eyes. 2-DG significantly reduced the total density of new blood vessels in tumors by 44% compared to saline controls (P < 0.001), but did not affect the density of mature vasculature.

CONCLUSIONS

Combination therapy with angiogenic and glycolytic inhibitors significantly enhanced tumor control. Synergistic effects were shown to be dependent on the temporal course of treatment, emphasizing optimal timing. 2-DG was shown to reduce the density of neovessels, demonstrating an antiangiogenic effect in vivo. As a result, angiogenic and glycolytic inhibitors may have significant potential as alternative therapies for treating children with retinoblastoma.

Nephrotoxicity of cancer treatment in children

Chronic renal impairment in children with cancer may be caused by the malignant process itself or result from adverse effects of treatment including cytotoxic drugs, radiotherapy, surgery or supportive treatment. Although severe renal chronic disease is uncommon, occurring in only 0.8% of long-term survivors of childhood cancer, 1.9% of all cases of established renal failure are due to malignancy and 0.8% to drug nephrotoxicity. The relative risk of severe renal chronic disease (compared with siblings) is 8.1, and that of renal failure or the need for dialysis is 8.9. The cytotoxic drugs most likely to cause important chronic nephrotoxicity are ifosfamide and cisplatin, both of which are used widely in many solid tumors and may cause chronic glomerular and/or renal tubular toxicity in 30–60% of treated children. Significant renal toxicity is less frequent with other chemotherapeutic drugs, but may result from treatment with carboplatin, methotrexate and nitrosoureas. Other cytotoxic drugs occasionally cause specific patterns of glomerular or tubular toxicity in children. Partial or unilateral nephrectomy leads to hypertrophy and hyperfiltration of the remaining renal tissue, and may result in microalbuminuria, hypertension and in rare cases, chronic renal impairment. Radiotherapy to a field including renal tissue may cause late onset chronic renal damage, manifest by hematuria, proteinuria, hypertension and anemia, sometimes progressing to chronic renal failure. Chronic nephrotoxicity is also common in survivors of hemopoietic stem cell transplantation, and is often multifactorial with contributions from prior chemotherapy, total body irradiation, immunosuppressive drugs and transplant complications, such as infection or hemorrhage. Patients at risk of renal damage should be monitored regularly with a defined surveillance protocol to enable timely management. General measures often employed to prevent or reduce nephrotoxicity include the use of intravenous hydration during drug administration and avoidance of known risk factors, such as high drug doses. Although numerous potentially nephroprotective drugs have been suggested and investigated, none have yet been introduced into clinical use in children due to the lack of proven efficacy. Improved understanding of the pathogenesis of nephrotoxicity is necessary to reduce the frequency and severity of this potentially serious complication of treatment in children with cancer.

Medulloblastoma in childhood: revisiting intrathecal therapy in infants and children

INTRODUCTION

Intrathecal chemotherapy is being explored in medulloblastoma in pre-school children as part of brain-sparing strategies and as an alternative to unacceptably neurotoxic cranio-spinal radiotherapy. The range of drugs suitable for this route of administration is restricted by the lack of research evidence of pharmacological suitability and efficacy of other drugs in medulloblastoma.

METHODS

Ideal clinical, biological, physicochemical and pharmaceutical properties for intrathecal administration were defined through literature review of pharmaceutical texts, Medline, Embase and consulting the manufacturers. A total of 126 chemotherapy agents were assessed against these criteria by searching the academic domain of pharmaceutical texts, computer databases and consultation with manufacturers.

RESULTS

Of the 126 candidate drugs, 99 were rejected because of documentation of their irritant nature, neurotoxicity and requirement for hepatic activation in standard pharmaceutical texts. Fifty were rejected for a single identifiable reason including, neurotoxicity (n = 24), irritant (n = 15), needs enzyme activation (n = 5), clinical evidence of intrathecal neurotoxicity (n = 4) and no evidence of tumour-specific efficacy (n = 2). Where two reasons were cited the justifications were: neurotoxic and irritant (n = 3) and needs activation and systemic administration results in equivalent concentration (n = 1). Twenty-seven drugs remained of which 12 were selected as eligible for further clinical investigation, and 15 were selected for further pre-clinical investigation.

CONCLUSIONS

The pre-determined criteria were not applicable, in their entirety, in the majority of drugs, due to lack of information in the academic domain, emphasising the importance of a more open approach for sharing basic drug information. The prioritised list of 12 candidate drugs for clinical trial and 15 for pre-clinical investigation justify that a concerted research effort in this area of practice is made.

Pharmacokinetic studies in children with cancer

We reviewed the current status of our knowledge of pharmacokinetics and pharmacodynamics of some anti-neoplastic drugs, used in the treatment of childhood cancer. Extrapolation of data from pharmacokinetic studies in adults to the paediatric population is often not feasible. Specific studies in children are needed. Of all reviewed anti-neoplastic drugs methotrexate appears to be most extensively studied. Methotrexate pharmacokinetics is correlated with toxicity and response to therapy, and it has been shown that individualized adaptive dosing of methotrexate is correlated with a better response to therapy without increasing toxicity in children with ALL and osteosarcoma. Of most of the other reviewed anti-neoplastic drugs it is demonstrated that pharmacokinetics is correlated with toxicity, and of some drugs a relationship of pharmacokinetics with response to therapy is demonstrated as well. In case of cytarabine, etoposide, and teniposide, individualized dosing also appears to be feasible. However, there is no evidence that this strategy improves response to therapy. Specifically data on pharmacokinetic and pharmacodynamic correlations and effect of pharmacokinetically guided, individualized dosing are important for the design of optimal cancer chemotherapy for individual patients. Unfortunately for a considerable number of anti-neoplastic drugs these specific data are lacking in children and future research is needed.

Carboplatin-epirubicin regimen for the treatment of hepatoblastoma

BACKGROUND

In order to lower the long-term toxicity of chemotherapy for hepatoblastoma patients, a prospective study was designed based on pre-operative chemotherapy combining carboplatin and epirubicin (CE).

PROCEDURES

Patients under 16 years of age with an epithelial hepatic tumor diagnosed by ultrasound or CT scan and a high serum alpha-foetoprotein (AFP) level were eligible. Patients were treated with a pre-operative chemotherapy regimen combining carboplatin 600 mg/m(2) and epirubicin 80 mg/m(2). Tumor resectability was assessed after four courses given at 3-week intervals. After surgery, patients were given two more courses of CE. Response was assessed based on a drop in serum AFP and tumor shrinkage.

RESULTS

Between July 1988 and August 1995, 27 patients with a hepatoblastoma were included. The initial PRETEXT group according to the SIOPEL classification was: group 2 (5 pts), group 3 (15 pts), group 4 (5 pts), and 2 pts were not assessed. Six patients had lung metastases. Response was partial response (PR) in 20/27 (74%) patients, disease was stable in 3 and 4 had progressive disease (PD). A complete surgical resection was performed in 21 pts. Five-year overall and disease-free survival (DFS) were respectively 56% (95%CI: 37-72%) and 63% (95%CI: 44-78%). During the same time period, 7 pts with a hepatocellular carcinoma were treated according to this protocol. Only one achieved a PR. Toxicity was mostly hematologic with > or =grade 3 leukopenia in 23% of the courses, > or =grade 3 thrombocytopenia in 29% of the courses and anemia in 22%.

CONCLUSION

The CE protocol is feasible and efficient in hepatoblastoma. However, only a randomized study will permit a valid comparison of the efficacy of cisplatin and carboplatin for the treatment of these patients.

Individual dosing of carboplatin based on drug monitoring in children receiving high-dose chemotherapy

Individual dosing of carboplatin based on drug monitoring was performed within a multi-centric phase I study based on high AUC-levels in children. Twelve patients (aged 3-17 years old) have been included: 3, 5, and 4 patients at the overall target ultrafilterable carboplatin AUC of 20, 25, or 30 mg/ml x min, respectively. Carboplatin was administered as a daily 60-min infusion, repeated on five consecutive days. The initial daily dose corresponding to the three first days was calculated according to the carboplatin clearance (CL) predicted from patients' characteristics (body weight, serum creatinine and nephrectomy status). Three blood samples were taken per patient. The individual CL were estimated by MAP (maximum a posteriori approach) Bayesian method implemented in the MP-K program. The doses for day 4 and 5 was adjusted in order to obtain the overall target AUC. Drug monitoring led to a change in the carboplatin dose (overall administered dose versus overall dose planned) ranging from -41% to +45%. Pharmacokinetics were performed at day 5 for 7/12 children: mean relative change between day 1 and day 5 was -11% showing a statistically significant, but limited, decrease of CL from day 1 to day 5. The percentage of difference between the observed and target overall AUC ranged between -7% and +14%. Three patients (one at each AUC level) who were previously treated with cisplatin experienced dose-limiting hearing loss. In conclusion, drug monitoring and dose adjustment is needed for the control of carboplatin plasma exposure when administering high doses of carboplatin in children.

Platinum agents in the treatment of osteosarcoma: efficacy of cisplatin vs. carboplatin in human osteosarcoma cell lines

BACKGROUND

Cisplatin (cDDP), when used either alone or, more often, in combination with other agents, especially adriamycin, achieves a high response rate in osteosarcoma. Its use, however, is limited by severe nephro- and neuro-toxicity. Second generation platinum compounds, most notably carboplatin (CBDCA), have been developed in order to attempt to reduce these dose-limiting toxicities, and thus improve the therapeutic ratio. Studies evaluating the role of combination CT containing CBDCA vs. cDDP have demonstrated differing results depending on the tumor type tested and its role in the treatment of osteosarcoma has yet to be clarified.

PROCEDURE

In this study, we compared the in vitro anti-tumor activity of cDDP and CBDCA in a panel of three human osteosarcoma cell lines (HOS, MG63, and U2OS).

RESULTS

cDDP and CBDCA (0-20 micromol) showed marked variation in cytotoxicity among the three cell lines. EC(50) values for CBDCA in HOS and MG63 cells were approximately two-fold higher than for cDDP and the ratio of AUC(CBDCA) to AUC(cDDP) varied from 1.8 in the HOS cell line to 2.3 in the MG63 cell line. Exposure of MG63 and HOS cells to either cDDP or CBDCA (1.67 and 13.5 micromol) caused a G2/M cell cycle arrest by 24 hr. Also evident was a sub G1 peak indicative of cell death by apoptosis. U2OS cells were relatively resistant to the cytotoxic effects of both drugs, although a cell cycle arrest in response to DNA damage was observed. This suggests that unlike MG63 and HOS cells, U2OS cells have either a more efficient repair pathway for platinum-induced DNA damage or are able to evade apoptosis. Examination of apoptotic events and cellular recovery demonstrated that both an 8-16-fold higher concentration and longer treatment period for CBDCA compared with cDDP was required to produce equivalent cell death and a loss of the ability of single cell clones to form colonies in both the HOS and MG63, but not the U2OS cell line.

CONCLUSIONS

Our findings suggest that CBDCA at a two- to four-fold higher concentration than cDDP has potential therapeutic activity in platinum sensitive osteosarcomas, particularly when cDDP cytotoxicity compromises therapeutic efficacy.

Intensive chemotherapy for children and young adults with metastatic primitive neuroectodermal tumors of the soft tissue

The MMT4 study was designed to explore an intensive chemotherapy regimen (MMT4-89) and the role of high-dose melphalan (MMT4-91) in children with metastatic soft tissue sarcoma, including extraosseous peripheral neuroectodermal tumor (PNET). Thirty-one patients with PNET were treated between 1989 and 1995 (11 according to MMT4-89 and 20 according to MMT4-91). Chemotherapy consisted of four CEVAIE cycles, each including three 3-week courses: CEV (carboplatin 500 mg/m(2), epirubicin 150 mg/m(2), vincristine 1.5 mg/m(2)), IVA ifosfamide 9 g/m(2), actinomycin 1.5 mg/m(2), vincristine 1.5 mg/m(2)), IVE (ifosfamide 9 g/m(2), etoposide 600 mg/m(2), vincristine 1.5 mg/m(2)). In MMT4-91 the fourth CEVAIE was replaced with melphalan 200 mg/m(2) with stem cell rescue. The CEV combination was evaluated as a window study. Surgery followed the second cycle. Radiotherapy was administered to post-surgical residual disease. The response rate was 55% after CEV, rising to 80% after the first CEVAIE. Twenty-five patients achieved complete remission (CR). Overall, the 5-year EFS was 22.6%: 36.4% and 15% for patients treated according to MMT4-89 and MMT4-91, respectively (P = 0.3). Local control was achieved in 77% of irradiated patients vs 45% of non-irradiated. Age >10 years was associated with significantly poorer outcome (P = 0.04). In conclusion, despite the high CR rate, intensive chemotherapy with or without high-dose melphalan appeared to have little impact on the survival of patients with metastatic extraosseus PNET.

Carboplatin before and during radiation therapy for the treatment of malignant brain stem tumours: a study by the Société Française d'Oncologie Pédiatrique

Childhood malignant brain stem tumours have a very poor prognosis with a median survival of 9 months despite radiotherapy. No chemotherapy has improved survival. However, carboplatin has been reported to have activity in glial tumours as well as antitumour synergy with radiation. Our aims were to test the response rate of these tumours to carboplatin alone and to evaluate the efficacy on survival of carboplatin alone followed by concurrent carboplatin and radiotherapy. Patients younger than 16 years with typical clinical and radiological presentation of infiltrating brain stem tumour, as well as histologically-documented cases in the atypical forms, were eligible. Two courses of carboplatin (1050 mg/m2 over 3 days) were administered initially. This treatment was followed by a chemoradiotherapy phase including five weekly carboplatin courses (200 mg/m2) and conventional radiotherapy. 38 eligible patients were included. No tumour response was observed after the initial phase. This schedule of first-line carboplatin followed by concurrent carboplatin and radiotherapy did not improve survival.

Prospective validation of renal function-based carboplatin dosing in children with cancer: A United Kingdom Children's Cancer Study Group Trial

PURPOSE

Carboplatin dosing in adults with cancer is based on renal function. The purpose of the current study was to validate a previously developed pediatric carboplatin-dosing formula.

PATIENTS AND METHODS

Thirty-eight pediatric patients were randomized to receive a carboplatin dose calculated according to surface area or a renal function-based dosing formula. On the next course of therapy, the alternative dosing method was used for each patient. Carboplatin pharmacokinetics (based on free plasma platinum concentrations) were measured after both courses.

RESULTS

The mean observed areas under the carboplatin concentration-versus-time curve (AUCs) after renal function- and surface area-based dosing were 98% and 95% of the target AUCs, respectively. The variation in the observed AUC was significantly less after renal function-based dosing (F test, P =.02), such that 74% of courses had an observed AUC within +/- 20% of the target value, versus 49% for courses after dosing according to surface area. Only one of 22 courses at the center with the most experience with renal function-based dosing was associated with an AUC outside +/- 20% of the target value, versus nine of 22 courses after surface area-based dosing in the same center. There was a relationship (r(2) =.71) between carboplatin AUC and thrombocytopenia in 10 neuroblastoma patients treated with a combination of carboplatin, vincristine, etoposide, and cyclophosphamide.

CONCLUSION

Renal function-based carboplatin dosing in children results in more consistent drug exposure than surface area-based drug administration.

Dose-related nephrotoxicity of carboplatin in children

This study investigated changes and the time course of these changes in renal function in children following treatment with carboplatin, and identified risk factors for nephrotoxicity. Glomerular and proximal renal tubular function were investigated before and up to 2 years after treatment in 23 children who received carboplatin. The main findings were reduced glomerular filtration rate (GFR), and increased renal tubular loss of magnesium, manifested by a low serum magnesium (S Mg). The mean fall in GFR was 22 ml min(-1) 1.73 m(-2) (P = 0.012), and in S Mg it was 0.17 mmol l(-1) (P = 0.0077). No patient had a clinically important reduction in GFR, and only one patient had symptomatic hypomagnesaemia. GFR and S Mg did not change over time after completion of treatment. Cumulative dose (CD) of carboplatin was inversely related to mean S Mg at the end of treatment (P = 0.031), and directly related to the fall in S Mg (P < 0.001). Calculated cumulative area under the plasma concentration versus time curve (AUC) of carboplatin was inversely related to S Mg after treatment (P = 0.004). Dose intensity (DI) of carboplatin was not shown to be related to S Mg following treatment. CD, AUC and DI of carboplatin were not related to GFR, nor change in GFR, after treatment. High CDs of carboplatin may be associated with evidence of renal damage qualitatively similar to but less severe than that caused by cisplatin. GFR and SMg should be carefully monitored when high CDs of carboplatin are used, or if carboplatin is combined with other nephrotoxic chemotherapy.

Role of chemotherapy alone or in combination with hyperthermia in the primary treatment of intraocular retinoblastoma: preliminary results

BACKGROUND

The efficacy of the etoposide-carboplatin combination in extraocular retinoblastoma is well known. This drug combination is therefore used in intraocular retinoblastoma, as primary reduction chemotherapy, before local treatment. The use of carboplatin in combination with diode laser hyperthermia as local treatment (thermochemotherapy) has been recently described as a conservative approach avoiding external beam radiotherapy in posterior pole tumours.

METHODS

All patients were reviewed, who were treated for retinoblastoma at the Institut Curie between June 1994 and October 1995, in whom treatment included either reduction chemotherapy or thermochemotherapy or both modalities successively. 23 patients presenting with unilateral (three) or bilateral (20) intraocular retinoblastoma received neoadjuvant chemotherapy consisting of two courses of etoposide 150 mg/m2/day and carboplatin 200 mg/m2/day for 3 days. 15 patients (17 eyes), eight of whom had already received neoadjuvant chemotherapy, were treated by thermochemotherapy.

RESULTS

Neoadjuvant chemotherapy: overall, seven eyes in seven patients could be treated conservatively, avoiding external beam irradiation, with a median follow up of 14 months. Thermochemotherapy: external beam irradiation was avoided for 14 of the 17 eyes treated.

CONCLUSION

Integration of neoadjuvant chemotherapy and combined treatment with carboplatin and diode laser, into the therapeutic armamentarium for retinoblastoma allows use of more aggressive treatments such as enucleation and external beam radiation.

Platinum-DNA adduct formation in leucocytes of children in relation to pharmacokinetics after cisplatin and carboplatin therapy

Platinum (Pt)-DNA adducts were measured in peripheral blood leucocytes (PBLs) from 24 children with solid tumours after standard cisplatin and/or carboplatin treatment. The relationship between Pt-DNA adduct levels and pharmacokinetics of cisplatin and carboplatin was investigated. Adduct measurements were performed by competitive enzyme-linked immunosorbent assay (ELISA) and plasma unbound Pt concentrations were measured by atomic absorption spectrophotometry (AAS). There was considerable interindividual variation in Pt-DNA adduct level that was weakly correlated (r2 = 0.32) with the area under the unbound drug concentration vs time curve (AUC) at 6 h after the start of cisplatin infusion, indicating that the variation in Pt-DNA adduct levels was primarily determined by factors other than AUC. No clear relationship between AUC and adduct levels was seen at 24 and 48 h after cisplatin or at 6, 24 or 48 h after carboplatin. Carboplatin produced lower levels of immunoreactive adducts than did cisplatin (1.3 +/- 0.6 nmol Pt g-1 DNA vs 3.2 +/- 1.7 nmol Pt g-1 DNA), despite a 20-fold higher unbound drug AUC for carboplatin (8.0 +/- 3.5 mg ml-1 min vs 0.4 +/- 0.2 mg ml-1 min). This study demonstrates that, after cisplatin and carboplatin treatment the drug-target interaction is determined by both pharmacokinetic and, predominantly, cellular factors. Intrinsic differences between the two complexes, primarily reactivity, probably explain the lower adduct levels observed after carboplatin treatment.

Successful treatment with ranimustine and carboplatin for recurrent intraocular retinoblastoma with vitreous seeding

This is the first report of successful treatment of recurrent retinoblastoma with vitreous seeding by a combination of ranimustine (MCNU) and carboplatin. The patient was diagnosed with bilateral retinoblastoma at 3 years of age. Although he received photocoagulation and radiotherapy for the left eye after enucleation of the right eye, a recurrent tumor associated with vitreous seeding developed 6 years later. The child underwent chemotherapy with cyclophosphamide and nimustine hydrochloride (ACNU), and a transient decrease of tumor cells in the vitreous was seen. We then changed the chemotherapy regimen to MCNU (70 mg/m2/ day for 1 day) and carboplatin (400 mg/m2/day for 2 days). After five courses of this chemotherapy, the tumor in the vitreous completely disappeared. No recurrence has been observed for > 4 years. Side effects, including myelosuppression, general fatigue, and vomiting, were observed during the course of chemotherapy, but they were ameliorated with supportive therapy. Neither nephro- nor ototoxicity was observed. The patient has useful vision. These results warrant further study of this novel drug combination in patients with recurrent, or even primary, retinoblastoma.

Population pharmacokinetics of carboplatin in children

OBJECTIVES

In pediatric patients, administration of carboplatin according to body surface area results in a large variation in the area under the plasma ultrafilterable carboplatin concentration versus time curve. A population pharmacokinetic study using the NONMEM program was undertaken to determine the effects of a variety of covariates on the clearance of ultrafilterable carboplatin.

PATIENTS

Plasma carboplatin pharmacokinetics were determined in 57 children (2 months to 18 years old, with serum creatinine levels ranging from 27 to 268 mumol/L) treated for various tumor types.

RESULTS

The best fit corresponded to the formula: clearance (ml/min) = 2.85.weight.(1-0.00357.serum creatinine).(1-0.372.Np) + 8.7 (with serum creatinine in micromoles per liter, weight in kilograms, and Np = 1 or 0 for unilateral nephrectomy or not, respectively). The interindividual variability in clearance, as expressed by the coefficient of variation, decreased from 74% (no covariates) to 49% by taking account of weight, and to 29% under the final regression formula.

CONCLUSION

The ability of this formula to predict carboplatin clearance in children should be evaluated prospectively and compared to a method based on the determination of the glomerular filtration rate.

Comparison of methods for the estimation of carboplatin pharmacokinetics in paediatric cancer patients

The antitumour and toxic effects of platinum drugs, in particular carboplatin, have been related to their plasma concentration and this has led to the concept of a target area under the plasma concentration-time curve (AUC) for carboplatin dosing. A formula based on renal function has been successfully applied to carboplatin dosing in adults and modified versions have also been proposed for paediatric patients. In order to monitor carboplatin AUC with maximum efficiency and minimum patient inconvenience, limited sampling strategies are desirable. A population method with Bayesian estimation is described, based on one or two samples taken following a dose of carboplatin. Population data were obtained from 22 paediatric patients treated with 200-1000 mg/m2 carboplatin as a 60-90 min infusion. Ultrafilterable carboplatin was determined by atomic absorption spectrophotometry. A two compartment model was fitted to each data set using the Maximum Likelihood estimator of the ADAPT programme. These parameter estimates provided the prior means and covariance matrix for the Bayesian estimator using a lognormal distribution. The test data sets consisted of ultrafilterable carboplatin concentrations in 23 patients (aged 1 month-18 years) who received similar treatment. The two compartment model was fitted to data sets containing one or two points, using the Bayesian maximum a posteriori (MAP) estimator and an error model derived from the population error model parameters. Results from the Bayesian analysis and other methods for the estimation of AUC, including relating clearance to surface area or to renal function, were evaluated by comparing the AUC estimate with the AUC determined by model-independent analysis. Overall, the optimal sampling strategy performed better than estimates based on renal function, which had a median bias of 5% and precision of 22%. With one data point at 60 min postinfusion, the median bias and precision were 3 and 6%, respectively. Addition of a second data point at 30 min during the infusion improved the estimate slightly (median bias -2%, precision 3%). Bayesian estimation produced more reliable estimates of AUC compared to values based on renal function, which in turn was slightly better than using surface area. A technique, developed in adult patients, for estimating AUC from a measurement of 24 h total plasma platinum was comparable to estimates based on renal function, but was less reliable. The estimation of carboplatin AUC can be performed using only one or two plasma samples and Bayesian analysis. This approach is less biased and more precise than methods based on surface area, renal function or total platinum at 24 h postdose, but is probably best used in combination with dosing based on renal function.