Phase II study of 21 day schedule oral etoposide in children. New Agents Group of the United Kingdom Children's Cancer Study Group (UKCCSG)

Phase II study of intravenous etoposide in patients with relapsed ependymoma (CNS 2001 04)

Background

Relapsed ependymoma has a dismal prognosis, and the role of chemotherapy at relapse remains unclear. This study prospectively evaluated the efficacy of intensive intravenous (IV) etoposide in patients less than 21 years of age with relapsed intracranial ependymoma (NCT00278252).

Methods

This was a single-arm, open-label, phase II trial using Gehan's two-stage design. Patients received IV etoposide 100 mg/m2 on days 1-3, 8-10, and 15-17 of each 28-day cycle, up to maximum of 6 cycles. Primary outcome was radiological response after 3 cycles. Pharmacokinetic analysis was performed in 10 patients.

Results

Twenty-five patients were enrolled and included in the intention-to-treat (ITT) analysis. Three patients were excluded in per-protocol (PP) analysis. After 3 cycles of etoposide, 5 patients (ITT 20%/PP 23%) had a complete response (CR), partial response (PR), or objective response (OR). Nine patients (ITT 36%/PP 41%,) had a best overall response of CR, PR, or OR. 1-year PFS was 24% in ITT and 23% in PP populations. 1-year OS was 56% and 59%, 5-year OS was 20% and 18%, respectively, in ITT and PP populations. Toxicity was predominantly hematological, with 20/25 patients experiencing a grade 3 or higher hematological adverse event.

Conclusions

This study confirms the activity of IV etoposide against relapsed ependymoma, however, this is modest, not sustained, and similar to that with oral etoposide, albeit with increased toxicity. These results confirm the dismal prognosis of this disease, provide a rationale to include etoposide within drug combinations, and highlight the need to develop novel treatments for recurrent ependymoma.

Relapsed Medulloblastoma in Pre-Irradiated Patients: Current Practice for Diagnostics and Treatment

Relapsed medulloblastoma (rMB) accounts for a considerable, and disproportionate amount of childhood cancer deaths. Recent advances have gone someway to characterising disease biology at relapse including second malignancies that often cannot be distinguished from relapse on imaging alone. Furthermore, there are now multiple international early-phase trials exploring drug-target matches across a range of high-risk/relapsed paediatric tumours. Despite these advances, treatment at relapse in pre-irradiated patients is typically non-curative and focuses on providing life-prolonging and symptom-modifying care that is tailored to the needs and wishes of the individual and their family. Here, we describe the current understanding of prognostic factors at disease relapse such as principal molecular group, adverse molecular biology, and timing of relapse. We provide an overview of the clinical diagnostic process including signs and symptoms, staging investigations, and molecular pathology, followed by a summary of treatment modalities and considerations. Finally, we summarise future directions to progress understanding of treatment resistance and the biological mechanisms underpinning early therapy-refractory and relapsed disease. These initiatives include development of comprehensive and collaborative molecular profiling approaches at relapse, liquid biopsies such as cerebrospinal fluid (CSF) as a biomarker of minimal residual disease (MRD), modelling strategies, and the use of primary tumour material for real-time drug screening approaches.

Oral etoposide as a single agent in childhood and young adult cancer in England: Still a poorly evaluated palliative treatment

BACKGROUND

Oral etoposide is commonly used in palliative treatment of childhood and young adult cancer without robust evidence. We describe a national, unselected cohort of young people in England treated with oral etoposide using routinely collected, population-level data.

METHODS

Patients aged under 25 years at cancer diagnosis (1995-2017) with a treatment record of single-agent oral etoposide in the Systemic AntiCancer Dataset (SACT, 2012-2018) were identified, linked to national cancer registry data using NHS number and followed to 5 January 2019. Overall survival (OS) was estimated for all tumours combined and by tumour group. A Cox model was applied accounting for age, sex, tumour type, prior and subsequent chemotherapy.

RESULTS

Total 115 patients were identified during the study period. Mean age was 11.8 years at cancer diagnosis and 15.5 years at treatment with oral etoposide. Median OS was 5.5 months from the start of etoposide; 13 patients survived beyond 2 years. Survival was shortest in patients with osteosarcoma (median survival 3.6 months) and longest in CNS embryonal tumours (15.5 months). Across the cohort, a median of one cycle (range one to nine) of etoposide was delivered. OS correlated significantly with tumour type and prior chemotherapy, but not with other variables.

CONCLUSIONS

This report is the largest series to date of oral etoposide use in childhood and young adult cancer. Most patients treated in this real world setting died quickly. Despite decades of use, there are still no robust data demonstrating a clear benefit of oral etoposide for survival.

Old drugs still work! Oral etoposide in a relapsed medulloblastoma

Medulloblastoma is the most common malignant brain tumor in children. Approximately 30% of children with medulloblastoma will progress or relapse despite being treated. New therapies have been proposed in recent years, including high-dose chemotherapy, immunotherapy, and targeted therapy. However, the best treatment for these patients remains unclear, and in this situation prognosis is poor. Oral etoposide has been used as a single agent or in combination for treating relapsed brain tumors since the 1990s. We report an 8-year-old patient with recurrent metastatic medulloblastoma who had an excellent response after treatment with oral etoposide, maintaining a great quality of life. As clinicians, we must always try to include our patients in clinical trials; however, when this is not possible, we should not forget that "old drugs" such as oral etoposide may work in some patients, with a good response of the tumor, and what is most important, providing the patient with a good quality of life.

A Phase II feasibility study of oral etoposide given concurrently with radiotherapy followed by dose intensive adjuvant chemotherapy for children with newly diagnosed high-risk medulloblastoma (protocol POG 9631): A report from the Children's Oncology Group

BACKGROUND

Children with high-risk medulloblastoma historically have had a poor prognosis. The Children's Oncology Group completed a Phase II study using oral etoposide given with radiotherapy followed by intensive chemotherapy.

PROCEDURE

Patients enrolled in the study had high-risk disease defined as ≥1.5 cm² of residual disease postsurgery or definite evidence of central nervous metastasis. All patients underwent surgery followed by radiotherapy. During radiation, the patients received oral etoposide (21 days on, 7 off) at an initial dose of 50 mg/m² per day (treatment 1), which was reduced to 35 mg/m² per day (treatment 2) due to toxicity. After radiotherapy, the patients received chemotherapy with three cycles of cisplatin and oral etoposide, followed by eight courses of cyclophosphamide and vincristine.

RESULTS

Between November 1998 and October 2002, 53 patients were accrued; 15 received treatment 1 and 38 treatment 2. Forty-seven patients (89%) were eligible. Response to radiation was excellent, with 19 (40.4%) showing complete response, 24 (51.1%) partial response, and four (8.5%) no recorded response. The overall 2- and 5-year progression-free survival (PFS) was 76.6 ± 6% and 70.2 ± 7%, respectively. The 2- and 5-year overall survival (OS) was 80.9 ± 6% and 76.6 ± 6%, respectively. Clinical response postradiation and PFS/OS were not significantly different between the treatment groups. There was a trend toward a difference in 5-year PFS between those without and with metastatic disease (P = 0.072).

CONCLUSIONS

Oral etoposide was tolerable at 35 mg/m² (21 days on and 7 days off) when given during full-dose irradiation in patients with high-risk medulloblastoma with encouraging survival data.

A phase II study to determine the efficacy and safety of oral treosulfan in patients with advanced pre-treated Ewing sarcoma ISRCTN11631773

We report a prospective Phase II study of efficacy and toxicity for oral treosulfan in advanced Ewing sarcoma. Twenty patients, median age 19 years (range 7-39) from five UK sites, were treated with oral treosulfan 1 g/m(2) daily for 7 days in 28. Primary endpoint was objective response rate. Best response was stable disease in one patient. All patients died of progressive disease, after median 6.41 months. Median progression free survival was 1.8 months. Toxicity was minimal. No activity was demonstrated for treosulfan at this dose. Progression free survival data should be able to be used for comparison when planning future clinical trials.

Metronomics: towards personalized chemotherapy?

Since its inception in 2000, metronomic chemotherapy has undergone major advances as an antiangiogenic therapy. The discovery of the pro-immune properties of chemotherapy and its direct effects on cancer cells has established the intrinsic multitargeted nature of this therapeutic approach. The past 10 years have seen a marked rise in clinical trials of metronomic chemotherapy, and it is increasingly combined in the clinic with conventional treatments, such as maximum-tolerated dose chemotherapy and radiotherapy, as well as with novel therapeutic strategies, such as drug repositioning, targeted agents and immunotherapy. We review the latest advances in understanding the complex mechanisms of action of metronomic chemotherapy, and the recently identified factors associated with disease resistance. We comprehensively discuss the latest clinical data obtained from studies performed in both adult and paediatric populations, and highlight ongoing clinical trials. In this Review, we foresee the future developments of metronomic chemotherapy and specifically its potential role in the era of personalized medicine.

Significant response to oral Etoposide in the treatment of an unresectable cardiac sarcoma

Primary cardiac sarcomas are rare and carry a poor prognosis. The standard of care is complete resection. Outcomes for patients without complete resection are dismal, and the benefit of adjuvant therapy is uncertain. A 9-year-old girl presented with a large right-sided cardiac mass. After biopsy, the tumor was classified as an undifferentiated sarcoma. Resection was not feasible due to apparent invasion of the right ventricle and atrioventricular groove. Treatment with oral etoposide resulted in a 97% reduction in tumor volume and allowed for complete resection of residual tumor. She is alive with no evidence of disease 25 months from diagnosis.

Relapse in medulloblastoma: what can be done after abandoning high-dose chemotherapy? A mono-institutional experience

PURPOSE

We retrospectively report strategies used for medulloblastoma patients progressing after craniospinal irradiation where we aimed for: symptom control, a satisfactory quality of life, accrual in phase 1-2 trials, when available, and the first two conditions could no longer be satisfied by already experienced second-line strategies.

METHODS

Surgery was used in cases of doubtful relapse or when only one site was affected. Radiotherapy was given whenever possible, especially to relieve symptoms. The main chemotherapy regimens were oral temozolomide/etoposide, intravenous (iv.) cisplatin/etoposide, iv. gemcitabine/oxaliplatin, an oral sonic hedgehog pathway inhibitor and oral melphalan.

RESULTS

Between 1998 and 2011, we treated 18 patients relapsed after median 20 months. Nine had relapsed locally, four had dissemination, three single metastases, and two had one synchronous local and metastatic recurrence. Responses to chemotherapy were seen in 32% of cases. The median hospital stay for treatments/complications was 19 days. The 1- and 3-year progression-free survival (PFS) rates were 28 ± 10% and 0%, respectively, for OS, they were 44 ± 12% and 22 ± 10% but no patient was cured. The median PFS after a first relapse was 7 months (range 1-29); the median OS was 7 months (range 4-44). No patients died due to treatment toxicity. Late recurrence (more than 1-2 years after diagnosis) and involvement of single sites were favorable prognostic factors.

CONCLUSIONS

Without succeeding in patients cure, we ensured them further treatment with short hospital stay thus affording low personal and social costs. The chances of cure may emerge from tailored therapies according to genetic stratification.

The use of palliative chemotherapy in pediatric oncology patients: a national survey of pediatric oncologists

BACKGROUND

Many children continue receiving chemotherapy after there is no realistic hope for cure. One factor that influences parental decisions to pursue medical therapies is physician preference. To date, no studies have described pediatric oncologists' perspectives and practices regarding palliative chemotherapy (PC).

PROCEDURE

We surveyed via email pediatric oncologists practicing in the U.S who are members of the Children's Oncology Group to achieve the following objectives: (1) Describe pediatric oncologists treatment considerations regarding the use of PC. (2) Assess treatment considerations that influenced pediatric oncologists' therapy recommendations for their most recent patient receiving PC. There were 422 participants (40.8%) who completed the survey.

RESULTS

The most important factors considered by pediatric oncologists when prescribing PC were the toxicity of the chemotherapy (4.90 mean SD = 0.36 utilizing 5 point scale with 1 = not important to 5 = very important), the preferences of the family (4.57; SD = 0.60), and the potential to decrease symptoms arising from tumor burden (4.42; SD = 0.65). These treatment considerations were not as important when PC was prescribed for their most recent patient. Similarly, the chief aims in prescribing PC were not achieved for recent patients receiving PC. For their most recent patient who received PC, 40.8% believe this treatment was primarily for parental wishes.

CONCLUSION

According to 80.2% of pediatric oncologists completing the survey, some patients receive chemotherapy beyond medical benefit and 40.8% of these oncologists have prescribed PC for the purpose of parental wishes to a recent patient. The chief aims in prescribing palliative chemotherapy were not achieved for recent patients.

Phase II study of cisplatin and oral VP16 in patients with refractory or relapsed Ewing sarcoma

BACKGROUND

Phase II trials demonstrate the activity of cisplatin in patients with refractory Ewing sarcoma family tumours (ESFT) and also the feasibility of giving cisplatin with oral VP16 in a variety of different cancers. This trial was conducted to evaluate the activity and toxicity profile of this combination delivered as outpatient therapy in patients with refractory/relapsed ESFT.

METHODS

Cisplatin was administered on days 1, 8 and 15 and days 29, 36 and 43 (70 mg/m(2)/dose for patients <21 years of age and 50 mg/m(2)/dose ≥21 years). VP16 was administered at a dose of 50 mg/m(2) on days 1-15 and days 29-43 inclusive. A three-stage Fleming statistical design was used for analysis.

RESULTS

Between January 2003 and October 2006, 45 patients aged between 5 and 46 years (median 19) were enrolled. Thirty-eight were evaluable for response. Patients had previously received one to three lines of chemotherapy (median = one). Seventy-three per cent of the patients had grade 3/4 neutropenia, 20 % developed fever, 40 % had grade 3/4 anaemia, 68 % grade 3/4 thrombocytopenia and 16 % grade 2/3 ototoxicity. Measured response after 2 cycles: 0 CR, 7 PR (18 %), 13 SD (34 %), 18 PD (48 %). There was excellent concordance between unidimensional and bidimensional criteria in 31 of 33 responses (94 %). PFS at 1 year was 39 %, with a median PFS of 6 months. Overall survival at 1 year was 44 %; median survival was 11 months.

CONCLUSIONS

Cisplatin combined with oral VP16 is well tolerated and has acceptable side effects, but limited clinical activity in refractory/relapsed ESFT.

Do pharmacokinetic polymorphisms explain treatment failure in high-risk patients with neuroblastoma?

PURPOSE

Neuroblastoma is the most common extracranial solid tumour in childhood. It accounts for 15% of all paediatric oncology deaths. In the last few decades, improvement in treatment outcome for high-risk patients has not occurred, with an overall survival rate <30-40%. Many reasons may account for such a low survival rate. The aim of this review is to evaluate whether pharmacogenetic factors can explain treatment failure in neuroblastoma.

METHODS

A literature search based on PubMed's database Medical Subject Headings (MeSH) was performed to retrieve all pertinent publications on current treatment options and new classes of drugs under investigation. One hundred and fifty-eight articles wer reviewed, and relevant data were extracted and summarised.

RESULTS AND CONCLUSIONS

Few of the large number of polymorphisms identified thus far showed an effect on pharmacokinetics that could be considered clinically relevant. Despite their clinical relevance, none of the single nucleotide polymorphisms (SNPs) investigated can explain treatment failure. These findings seem to reflect the clinical context in which anti-tumour drugs are used, i.e. in combination with multimodal therapy. In addition, many pharmacogenetic studies did not assess (differences in) drug exposure, which could contribute to explaining pharmacogenetic associations. Furthermore, it remains unclear whether the significant activity of new drugs on different neuroblastoma cell lines translates into clinical efficacy, irrespective of resistance or myelocytomatosis viral related oncogene, neuroblastoma derived (MYCN) amplification. Elucidation of the clinical role of pharmacogenetic factors in the treatment of neuroblastoma demands an integrated pharmacokinetic-pharmacodynamic approach to the analysis of treatment response data.

Phase II study of metronomic chemotherapy with bevacizumab for recurrent glioblastoma after progression on bevacizumab therapy

We evaluated the efficacy of metronomic etoposide or temozolomide administered with bevacizumab among recurrent glioblastoma (GBM) patients who progressed on prior bevacizumab therapy in a phase 2, open-label, two-arm trial. Twenty-three patients received bevacizumab (10 mg/kg) every 2 weeks with either oral etoposide (50 mg/m2) daily for 21 consecutive days each month or daily temozolomide (50 mg/m2). The primary endpoint was 6-month progression-free survival (PFS-6) and secondary endpoints included safety and overall survival. Both the etoposide and temozolomide arms of the study closed at the interim analysis due to lack of adequate anti-tumor activity. No radiographic responses were observed. Although 12 patients (52%) achieved stable disease, PFS-6 was 4.4% and the median PFS was 7.3 weeks. The only grade 4 adverse event was reversible neutropenia. Grade 3 toxicities included fatigue (n = 2) and infection (n = 1). Metronomic etoposide or temozolomide is ineffective when administered with bevacizumab among recurrent GBM patients who have progressed on prior bevacizumab therapy. Alternative treatment strategies remain critically needed for this indication.

[Metronomic chemotherapy in pediatric oncology: hype or hope?]

Angiogenesis is crucial for the growth of cancer. As such, it has become an established target in fighting cancer. Metronomic chemotherapy-the chronic administration of chemotherapy at relatively low, minimally toxic doses on a frequent schedule of administration at close regular intervals, with no prolonged drug-free breaks-is a potential novel approach to controlling advanced cancer disease. It is thought to work primarily through antiangiogenic mechanisms and has the property of killing resistant cancer cells while significantly reducing undesirable toxic side effects. We review the data regarding the use of metronomic chemotherapy in children with cancer and discuss its potential uses and limits.

Role of radiotherapy and chemotherapy in the risk of secondary leukaemia after a solid tumour in childhood

The aim of this study was to determine the therapy-related risk factors for the occurrence of leukaemia after childhood solid cancer. Among 4204 3-year survivors of a childhood cancer treated in eight French and British centres before 1986, 11 patients developed leukaemia as a second malignant neoplasm (SMN). Compared with the leukaemia incidence in the general French and British populations, the standardised incidence ratio (SIR) of leukaemia was 7.8 (95% CI 4.0-13.4). It decreased from 20.3 (95% CI 8.3-41.2) during the first years of follow-up, to 2.2 (95% CI 0.1-9.7) between 10 and 20 years, but rose again to 14.8 (95% CI 3.7-38.3) 20 or more years after the first cancer. Radiotherapy appeared to increase the risk of leukaemia at moderate weighted doses to active bone marrow; the relative risk (RR) was 4.2 (95% CI 0.8-20.7) for doses ranging from 3 to 6.6 Gy. A greater RR was observed for epipodophyllotoxins and for vinca alkaloids. No specific type of first malignant neoplasm (FMN) was found to lead to a higher risk of secondary leukaemia. Epipodophyllotoxins and vinca alkaloids at high doses and moderate weighted radiation doses to active bone marrow may contribute independently to an increased risk of leukaemia for patients treated for childhood cancer. Our results suggest that the long-term risk of secondary leukaemia could be higher than previously reported.

Treatment with oral etoposide for childhood recurrent ependymomas

In this study the authors retrospectively evaluated the feasibility and effectiveness of prolonged oral etoposide therapy in children with recurrent ependymoma. Twelve ependymoma patients with documented recurrent or persistent disease were treated between May 1998 and October 2003. All patients were treated monthly with oral VP-16 administered at a dose of 50 mg/m2/d for 21 days, with a 7-day interval between cycles, for a planned minimum number of six cycles. Response (complete plus partial) after two cycles occurred in 5 of the 12 patients (41.6%). Response plus stable disease occurred in 10 of the 12 (83.3%), with a median duration of response or stable disease of 7 months (range 4-30). The median survival was 7 months; the 2-year progression-free survival was 16.7%. These results emphasize that oral etoposide is an attractive option for childhood recurrent ependymomas in terms of administration, tolerability, and neuroradiologic response.

High cumulative rate of secondary leukemia after continuous etoposide treatment for solid tumors in children and young adults

BACKGROUND

In a national pediatric case-control study, we observed a very high relative risk of leukemia in patients who had received continuous etoposide (CE) over 6 months or more, but we could not estimate the absolute risk. The purpose of the present study was to estimate this absolute risk after CE.

PROCEDURES

We report a study of 18 patients with refractory or recurrent tumors who received CE over 6 months or more between 1995 and 1997. It was administered either 3 days a week for 3/4 weeks ("3 x 3", 14 patients) or 7 days a week for 3/4 weeks ("7 x 3", four patients).

RESULTS

Five patients developed secondary leukemia 10-25 months after the initiation of CE. All the others died of their first tumor. The cumulative incidence of leukemia at 30 months was 28% (95% CI, 10%-53%). A chromosome 11q23 rearrangement was found in 3/5 cases. All four patients who received the "7 x 3" CE schedule developed leukemia compared to 1/14 treated with the "3 x 3" CE schedule (P = 0.002).

CONCLUSIONS

Given its efficacy, CE may still have a place as a palliative treatment. However, the risk of leukemia must be borne in mind when considering its use in patients with a better prognosis.

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.

Oral etoposide for recurrent/progressive sarcomas of childhood

BACKGROUND

Etoposide (VP-16) is a topoisomerase II inhibitor that is effective in a broad spectrum of pediatric and adult malignancies. Chronic, low-dose, oral VP-16 has also been shown to be active in some recurrent malignancies mostly in adults. The aim of this prospective, single institution study is to assess the efficacy and toxicity of oral VP-16 in children with progressive or recurrent (P/R) sarcomas.

PROCEDURE

Twenty-one children (10 girls and 11 boys) with R/P sarcomas and a median age of 11 years (range 3-16 years) were enrolled in this study. The diagnosis was Ewing sarcoma family tumor (ESFT) in seven, osteosarcoma in eight, rhabdomyosarcoma in four, clear cell sarcoma of soft tissue in one, fibrosarcoma in one patient. Oral VP-16 was administered at a dose of 50 mg/m(2)/daily for 20 days. The next course was initiated after a 10 day rest. Response to oral VP-16 was assessed after two courses.

RESULTS

There was an objective response (one complete response [CR], two partial responses [PR]) in three patients (14%) by two courses of oral VP-16 alone. One of these patients with PR achieved CR by the use of radiotherapy (RT) and further oral VP-16. Two more patients (9.5%) achieved CR by RT and oral VP-16. Eight (38%) patients had disease stabilization for 2-15 months. Two patients (9.5%) are long-term survivors. They are alive with no evidence of disease (NED) 79 and 94 months from time of relapse/progressive disease (PD). A patient developed acute myeloid leukemia and died. There was no major acute toxicity related to oral VP-16 in a total of 126 courses.

CONCLUSIONS

Oral VP-16 therapy is simple, relatively nontoxic, and does not necessitate hospitalization. The cure rate is small. Given the risk of second malignancy, especially in children with previous exposure to topoisomerase II inhibitors and alkylating agents, this regimen may be used as a palliative treatment or in patients with poor prognosis.

Pharmacokinetic Optimisation of Treatment with Oral Etoposide

Etoposide is a derivative of podophyllotoxin widely used in the treatment of several neoplasms, including small cell lung cancer, germ cell tumours and non-Hodgkin's lymphomas. Prolonged administration of etoposide aims for continuous inhibition of topoisomerase II, the intracellular target of etoposide, thus preventing tumour cells from repairing DNA breaks. However, the clinical advantages of extended schedules as compared with conventional short-term infusions remain unclear. Oral administration of etoposide represents the most feasible and economic strategy to maintain effective concentrations of drug for extended times. Nevertheless, the efficacy of oral etoposide therapy is contingent on circumventing pharmacokinetic limitations, mainly low and variable bioavailability. Inhibition of small bowel and hepatic metabolism of etoposide with specific cytochrome P450 inhibitors or inhibition of the intestinal P-glycoprotein efflux pump have been attempted to increase the bioavailability of oral etoposide, but the best results were obtained with daily oral administration of low etoposide doses (50-100 mg/day for 14-21 days). Saturable absorption of etoposide was reported for doses greater than 200 mg/day, whereas lower doses were associated with increased bioavailability, although they were characterised by high inter- and intrapatient variability. Pharmacokinetic parameters such as plasma trough concentration between two oral administrations (C(24,trough)), drug exposure time above a threshold value and area under the plasma concentration-time curve have been correlated with the pharmacodynamic effect of oral etoposide. Pharmacokinetic-pharmacodynamic relationships indicate that severe toxicity is avoided when peak plasma concentrations do not exceed 3-5 mg/L and C(24,trough) is under the threshold limit of 0.3 mg/L. To maintain effective etoposide plasma concentrations during prolonged oral administration, pharmacokinetic variability must be monitored in each patient, taking account of factors from many pharmacokinetic studies of etoposide, including absorption, distribution, protein binding, metabolism and elimination. Dosage reduction is generally useful to avoid haematological toxicity in patients with renal dysfunction (creatinine clearance <50 mL/min). The need for dosage adjustment based on liver function in patients with liver dysfunction is not completely defined, but generally is not indicated in patients with minor liver dysfunction. Adaptive dosage adjustment based on individual pharmacokinetic parameters, estimated using limited sampling strategies and population pharmacokinetic models, is more appropriate. This approach has been used with success in different clinical trials to increase the etoposide dosage, without significantly increasing toxicity. Various pharmacodynamic models have been proposed to guide etoposide oral dosage. However, they lack precision and accuracy and need to be refined by considering other predictor variables in order to extend their application in current clinical practice.

Pharmacokinetics and pharmacodynamics of oral etoposide in children with relapsed or refractory acute lymphoblastic leukemia

PURPOSE

To study the pharmacokinetics and pharmacodynamics of once- versus twice-daily oral etoposide in children with relapsed or refractory acute lymphoblastic leukemia (ALL).

PATIENTS AND METHODS

Fifty-eight patients were randomly assigned to etoposide at 50 mg/m(2)/d with once- versus twice-daily doses for 22 days. On day 8, vincristine, asparaginase, and dexamethasone were started. Etoposide pharmacokinetics and pharmacodynamics were studied for 47, 28, and 26 patients on day 1, 8, and 22, respectively, of remission reinduction therapy.

RESULTS

Of 48 patients with pharmacokinetic data, 42 (87.5%) achieved complete remission, three (6.3%) failed to achieve remission, and three (6.3%) died during induction. Median etoposide day 8 area under concentration-time curve (AUC) and cumulative AUC tended to be greater (P =.06 and P =.07, respectively) in patients (n = 23) who achieved complete remission (24 and 522 micro mol/L x h, respectively) than in patients (n = 3) who did not (14 and 303 micro mol/L x h, respectively). Three of eight patients with plasma concentrations exceeding 1.7 micro M (1 micro g/mL) for more than 8 hours daily, compared with one of 20 patients with concentrations exceeding 1.7 micro M for <or= 8 hours daily, were unable to receive all 22 days of etoposide because of toxicity. There was no difference in the AUC at day 1 or day 8 with once- versus twice-daily doses (P =.55 and P =.86, respectively).

CONCLUSION

A pharmacodynamic relationship exists between systemic etoposide exposure and response to therapy when oral etoposide is used as part of remission induction regimens for relapsed or refractory childhood ALL.

Risk of secondary leukemia after a solid tumor in childhood according to the dose of epipodophyllotoxins and anthracyclines: a case-control study by the Société Française d'Oncologie Pédiatrique

PURPOSE

To estimate the risk of secondary leukemia as a function of the dose of epipodophyllotoxins and anthracyclines.

METHODS

We conducted a case-control study of the risk of secondary leukemia or myelodysplasia after a solid tumor in childhood within the Société Française d'Oncologie Pédiatrique, including 61 patients with leukemia matched with 196 controls. The characteristics of the first cancer, the patient's family history of cancer, and the treatment (type, cumulative dose of chemotherapy, schedule of etoposide administration, and radiation dose delivered to active bone marrow) were compared in the two groups.

RESULTS

Only two factors were found to increase the risk of leukemia in multivariate analysis, namely, the type of the first tumor, with an excess risk in patients with Hodgkin's disease (relative risk 6.4; 95% confidence interval [CI], 1.6 to 24) or osteosarcoma (relative risk 5; 95% CI, 1.3 to 19), and exposure to epipodophyllotoxins and anthracyclines. The risk of leukemia increased regularly with the cumulative dose of etoposide. In summary, patients who received between 1.2 and 6 g/m(2) of epipodophyllotoxins or more than 170 mg/m(2) of anthracyclines had a seven-fold higher risk (95% CI, 2.6 to 19) compared with patients who received lower doses or none of these drugs. The risk of leukemia in patients who received more than 6 g/m(2) of epipodophyllotoxins was multiplied by 197 (95% CI, 19 to 2,058). The risk of leukemia was not increased by exposure to alkylating agents or radiotherapy.

CONCLUSION

Both epipodophyllotoxins and anthracyclines increase the risk of secondary leukemia. The current challenge is to minimize the mutagenic effects of these drugs by diminishing cumulative doses without losing the therapeutic benefits.

Caring for children with advanced cancer integrating palliative care

The care of children with advanced cancer is multifaceted. Treatment should focus on continued efforts to control the underlying illness whenever possible. At the same time, children and their families should have access to interdisciplinary care aimed at promoting optimal physical, psychological and spiritual wellbeing. Open and compassionate communication can best facilitate meeting the goals of these children and families. However, there remain significant barriers to achieving optimal care related to lack of formal education, reimbursement issues and the emotional impact of caring for a dying child. Future research efforts should focus on ways to enhance communication, symptom management and quality of life for children with advanced cancer and their families. As efforts to break down barriers and create the evidence base continue, we conclude as follows: this is a most rewarding part of the practice of medicine. A kind word and caring attitude are remembered for decades.

Bioavailability and pharmacokinetic features of etoposide in childhood acute lymphoblastic leukemia patients

The bioavailability and pharmacokinetic characteristics of etoposide were studied in 12 relapsed B-lineage acute lymphoblastic leukemia (ALL) patients after both intravenous (i.v.) infusion and oral administration. Following a 1 hour i.v. infusion of 50 mg/m2 etoposide, the elimination half-life ranged from 49.8 min to 509.4 min (mean +/- SD = 218.6 +/- 134.7 min), the MRT ranged from 71.8 to 734.9 min (mean +/- SD = 315.4 +/- 194.3 min) and the systemic clearance of etoposide ranged from 15.7 to 38.0 ml/min/m2 (mean +/- SD = 24.1 +/- 7.0 ml/min/m2). The AUC ranged from 2234.9 to 5427.0 microM.min) (mean +/- SD = 3827.8 +/- 1069.5 microM.min) and Vc ranged from 2026.9 to 13,505.2 ml/m2 (mean +/- SD = 6825.4 +/- 3278.5 ml/m2). The maximum plasma etoposide levels ranged from 6.0 to 28.4 microM (mean +/- SD = 13.6 +/- 6.3 microM). The bioavailability of oral etoposide was determined by comparing the AUC following i.v. infusion to the AUC following oral administration in the same patient. The overall bioavailability (mean +/- SD) was 60.6 +/- 22.4% (ranged from 17.6% to 91.2%). The elimination half-life following oral administration (mean +/- SD) was 209.8 +/- 196.3 min (ranged from 51.0 to 794.2 min). The time required to reach the maximum plasma etoposide concentration was 145.4 +/- 118.7 min (ranged from 23.7 to 396.9 min). To our knowledge, this is the first report concerning the bioavailability of etoposide in pediatric leukemia patients. All of the other pharmacokinetic properties of etoposide in pediatric B-lineage ALL leukemia patients reported here were similar to those described previously.

Treatment-related leukaemia--a clinical and scientific challenge

The development of a second tumour, including treatment-related leukaemia (TRL), is the most devastating complication of intensive cancer chemotherapy. This is especially relevant in the paediatric population as over 70% of children diagnosed with a malignancy will now live at least 5 years. Most TRLs are myeloid leukaemias and carry an overall poor prognosis when compared with their de novo counterparts. Despite the well known association with specific cytotoxic agents, improved understanding of the pathogenesis and risk factors of TRL is ultimately essential if we are to develop successful strategies for prevention and treatment. Here we review these aspects, together with the clinical and diverse biological features of this complication and the efficacy of current therapy.

The effects of dose, route of administration, drug scheduling and MDR-1 gene transfer on the genotoxicity of etoposide in bone marrow

We have used the bone marrow micronucleus assay (BMMN) as a measure of clastogenicity, in response to etoposide exposure in murine bone marrow. Oral delivery of etoposide resulted in a reduced number of micronucleated polychromatic erythrocytes (MPE) relative to the same dose delivered intraperitoneally (P < 0.001). Daily fractionation of the oral schedule of etoposide led to a more than six-fold increase in cumulative MPE frequency over that observed with the same total, unfractionated dose, with the potency of the response increasing with serial exposure (r = 0.79). Retrovirally-mediated expression of MDR1 in murine bone marrow resulted in partial protection against the clastogenic activity of etoposide relative to mock transduced control mice. The model system developed has indicated a variety of factors able to influence the genotoxicity of etoposide. It should now be possible to further exploit this model in order to define other factors governing haemopoietic sensitivity to etoposide.

Metastatic medulloblastoma in 10-year-old girl treated successfully with chemotherapy without radiotherapy

We report a case of high risk medulloblastoma with leptomeningeal intracranial and spinal metastasis in a 10-year-old girl treated successfully with conventional prolonged chemotherapy without radiotherapy. This is a particular case of medulloblastoma that at onset did not receive standard therapy for medulloblastoma i.e. neither surgery nor craniospinal irradiation. This 10-year-old Chinese girl affected with localized medulloblastoma was previously treated at a medical department in China only with radiotherapy on the posterior fossa. When the child arrived in Italy with progressed metastatic medulloblastoma, she was treated with carboplatin/etoposide association i.v. followed by oral etoposide and partial surgery of the primitive mass. The schedule of chemotherapy was etoposide 300 mg/sqm followed by carboplatin 1000 mg/sqm in one day every 21-28 days for the first six courses, then etoposide 200 mg/sqm and carboplatin 600 mg/sqm in one day every 28-35 days for further 11 courses and oral etoposide 50 mg/sqm/day for ten consecutive days and one week interval between two cycles for one year. At present the girl is alive and disease-free, and has been off-therapy for 31 months. Interestingly, in this case a long-lasting complete remission was obtained without radiotherapy and without myeloablative chemotherapy. Oral etoposide played an important role in achieving a complete remission.

Secondary leukemia in a child with neuroblastoma while on oral etoposide: what is the cause?

To date little has been reported about the risk of therapy-related leukaemia (t-AML) in children receiving oral etoposide therapy. The authors present a case of t-AML that developed in a child with metastatic neuroblastoma 18 months after he received oral etoposide, given for palliation purpose. The leukemic blasts were examined by morphological, immunohistochemical, cytogenetic, and molecular genetic analyses. Although the t-AML developed following oral etoposide therapy, the child had previously received high-dose, multiagent chemotherapy, and rearrangement of the MLL gene was not demonstrated. The use of modern multiagent therapy often makes it difficult to appropriately apportion blame for causation of specific side effects. Moreover, the etiology of t-AML and mechanism of leukemogenesis are likely to be multifactorial and complex. Further studies on the precise association with different therapies are thus needed. Oral etoposide remains an effective palliative agent and its usage should not be excluded without most careful consideration of the risks.

Ten-day schedule oral etoposide therapy in advanced childhood malignancies

PURPOSE

The activity of etoposide (VP-16) has been demonstrated to be schedule-dependent. Several studies have been conducted on the efficacy and safety of different schedules of VP-16 both in adults and in children, but the optimal schedule has not been determined.

METHODS

In the current study, the feasibility and effectiveness of prolonged oral VP-16 in children with high-risk malignancies were evaluated. Between April 1995 and February 1999, 15 pretreated patients with high-risk tumors received oral VP-16. The schedule of therapy was oral VP-16 50 mg/m2/day for 10 consecutive days and 1-week interval between cycles. Therapy was stopped after 1 year of treatment or at time of progressive disease or possible surgery. All patients had received parenteral VP-16 in their earlier chemotherapy.

RESULTS

Twelve patients were evaluable for tumor response. After 2 to 4 months of treatment, one patient had complete remission (CR), two had partial response (PR), two had minor response (MR), two had mixed response (MxR), three had stable disease (SD), and two had progressive disease (PD). A useful palliative effect was noted in patients with stable disease. In three patients, oral VP-16 was administered for maintenance therapy. After an average follow-up of 27.5 months (range, 7-41 months), five patients are alive without disease (in three, total surgery was performed after VP-16 therapy) and three patients are alive with disease. Six patients died of progressive disease, and one died of promyelocytic leukemia. One patient had Grade 34 thrombocytopenia; in the remaining patients, no acute toxicity was observed during treatment.

CONCLUSIONS

This schedule of oral VP-16 produced CRs, PRs, and MRs in medulloblastoma, neuroblastoma, teratocarcinoma, and ependymoma. Stable disease was observed in three patients, one with an Askin tumor, one with medulloblastoma, and one with hepatoblastoma. Given the possible leukemogenic risk, this schedule should be used as a palliative form of therapy or in patients with poor prognosis..

Oral etoposide for refractory and relapsed neuroblastoma

PURPOSE

To describe the efficacy of oral etoposide against resistant stage 4 neuroblastoma.

PATIENTS AND METHODS

Patients with refractory or recurrent stage 4 neuroblastoma were treated with etoposide 50 mg/m(2) taken orally each day, in two or three divided doses, for 21 consecutive days. Treatment could be repeated after a 1-week period. Extent-of-disease studies included imaging with 131-iodine-metaiodobenzylguanidine and extensive bone marrow (BM) sampling.

RESULTS

Oral etoposide was used in 20 children between the ages of 2 and 11 years (median, 6 years). Prior treatment included high doses of alkylating agents and a median of 4.5 cycles of etoposide-containing chemotherapy, with cumulative etoposide doses of 1,800 mg/m(2) to 3,935 mg/m(2) (median, 2,300 mg/m(2)). Oral etoposide produced antineuroblastoma effects in four of four children with disease refractory to intensive induction treatment; sampling variability could account for resolution (n = 3) or reduction (n = 1) of BM involvement, but improvement in other markers also occurred. Antineuroblastoma effects were also evident in five of five children with asymptomatic relapses after a long chemotherapy-free interval: BM disease resolved and all other disease markers significantly improved in two patients, and disease markers improved or stabilized in three patients on treatment for more than 6 months. In these nine patients, extramedullary toxicity was absent, neutropenia did not occur, transfusional support was not needed, and preliminary data suggested little immunosuppression (phytohemagglutinin responses). Oral etoposide was ineffective in all (11 of 11) patients with rapidly growing tumor masses.

CONCLUSION

Given the absence of toxicity to major organs, the minimal myelosuppression or immunosuppression, and the antineoplastic activity in patients with low tumor burdens after high-dose chemotherapy, limited use of low-dose oral etoposide should be considered for inclusion in postinduction consolidative treatment programs aimed at eradicating minimal residual disease.