Pediatric phase II cancer chemotherapy trials: a Pediatric Oncology Group study

Risk and Benefit for Targeted Therapy Agents in Pediatric Phase II Trials in Oncology: A Systematic Review with a Meta-Analysis

BACKGROUND

For research with human participants to be ethical, risk must be in a favorable balance with potential benefits. Little is known about the risk/benefit ratio for pediatric cancer phase II trials testing targeted therapies.

OBJECTIVE

Our aim was to conduct a systematic review of preliminary efficacy and safety profiles of phase II targeted therapy clinical trials in pediatric oncology.

METHODS

Our protocol was prospectively registered in PROSPERO (CRD42020146491). We searched EMBASE and PubMed for phase II pediatric cancer trials testing targeted agents. We included solid and hematological malignancy studies published between 1 January, 2015 and 27 February, 2020. We measured risk using drug-related grade 3 or higher adverse events, and benefit by response rates. When possible, data were meta-analyzed. All statistical tests were two-sided.

RESULTS

We identified 34 clinical trials (1202 patients) that met our eligibility criteria. The pooled overall response rate was 24.4% (95% confidence interval [CI] 14.5-34.2) and was lower in solid tumors, 6.4% (95% CI 3.2-9.6), compared with hematological malignancies, 55.1% (95% CI 35.9-74.3); p < 0.001. The overall fatal drug-related (grade 5) adverse event rate was 1.6% (95% CI 0.6-2.5), and the average drug-related grade 3/4 adverse event rate per person was 0.66 (95% CI 0.55-0.78).

CONCLUSIONS

We provide an estimate for the risks and benefits of participation in pediatric phase II cancer trials. These data may be used as an empirical basis for informed communication about benefits and burdens in pediatric oncology research.

Predictors of Success of Phase II Pediatric Oncology Clinical Trials

BACKGROUND

There are limited data to predict which novel childhood cancer therapies are likely to be successful. To help rectify this, we sought to identify the factors that impact the success of phase II clinical trials for pediatric malignancies.

MATERIALS AND METHODS

We examined the impact of 24 preclinical and trial design variables for their influence on 132 phase II pediatric oncology clinical trials. Success was determined by an objective assessment of patient response, with data analyzed using Fisher's exact test, Pearson's chi-square test, and logistic regression models.

RESULTS

Trials that evaluated patients with a single histological cancer type were more successful than those that assessed multiple different cancer types (68% vs. 47%, 27%, and 17% for 1, 2-3, 4-7, and 8+; p < .005). Trials on liquid or extracranial solid tumors were more successful than central nervous system or combined trials (70%, 60%, 38%, and 24%; p < .005), and trials of combination therapies were more successful than single agents (71% vs. 28%; p < .005). Trials that added therapies to standard treatment backbones were more successful than trials testing novel therapies alone or those that incorporated novel agents (p < .005), and trials initiated based on the results of adult studies were less likely to succeed (p < .05). For 61% of trials (80/132), we were unable to locate any relevant preclinical findings to support the trial. When preclinical studies were carried out (52/132), there was no evidence that the conduct of any preclinical experiments made the trial more likely to succeed (p < .005).

CONCLUSION

Phase II pediatric oncology clinical trials that examine a single cancer type and use combination therapies have the highest possibility of clinical success. Trials building upon a standard treatment regimen were also more successful. The conduct of preclinical experiments did not improve clinical success, emphasizing the need for a better understanding of the translational relevance of current preclinical testing paradigms.

IMPLICATIONS FOR PRACTICE

To improve the clinical outcomes of phase II childhood cancer trials, this study identified factors impacting clinical success. These results have the potential to impact not only the design of future clinical trials but also the assessment of preclinical studies moving forward. This work found that trials on one histological cancer type and trials testing combination therapies had the highest possibility of success. Incorporation of novel therapies into standard treatment backbones led to higher success rates than testing novel therapies alone. This study found that most trials had no preclinical evidence to support initiation, and even when preclinical studies were available, they did not result in improved success.

Retinoic acid postconsolidation therapy for high-risk neuroblastoma patients treated with autologous haematopoietic stem cell transplantation

BACKGROUND

Neuroblastoma is a rare malignant disease and mainly affects infants and very young children. The tumours mainly develop in the adrenal medullary tissue, with an abdominal mass as the most common presentation. About 50% of patients have metastatic disease at diagnosis. The high-risk group is characterised by metastasis and other features that increase the risk of an adverse outcome. High-risk patients have a five-year event-free survival of less than 50%. Retinoic acid has been shown to inhibit growth of human neuroblastoma cells and has been considered as a potential candidate for improving the outcome of patients with high-risk neuroblastoma. This review is an update of a previously published Cochrane Review.

OBJECTIVES

To evaluate the efficacy and safety of additional retinoic acid as part of a postconsolidation therapy after high-dose chemotherapy (HDCT) followed by autologous haematopoietic stem cell transplantation (HSCT), compared to placebo retinoic acid or to no additional retinoic acid in people with high-risk neuroblastoma (as defined by the International Neuroblastoma Risk Group (INRG) classification system).

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) in the Cochrane Library (2016, Issue 11), MEDLINE in PubMed (1946 to 24 November 2016), and Embase in Ovid (1947 to 24 November 2016). Further searches included trial registries (on 22 December 2016), conference proceedings (on 23 March 2017) and reference lists of recent reviews and relevant studies. We did not apply limits by publication year or languages.

SELECTION CRITERIA

Randomised controlled trials (RCTs) evaluating additional retinoic acid after HDCT followed by HSCT for people with high-risk neuroblastoma compared to placebo retinoic acid or to no additional retinoic acid. Primary outcomes were overall survival and treatment-related mortality. Secondary outcomes were progression-free survival, event-free survival, early toxicity, late toxicity, and health-related quality of life.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane.

MAIN RESULTS

The update search did not identify any additional studies. We identified one RCT that included people with high-risk neuroblastoma who received HDCT followed by autologous HSCT (N = 98) after a first random allocation and who received retinoic acid (13-cis-retinoic acid; N = 50) or no further therapy (N = 48) after a second random allocation. These 98 participants had no progressive disease after HDCT followed by autologous HSCT. There was no clear evidence of difference between the treatment groups either in overall survival (hazard ratio (HR) 0.87, 95% confidence interval (CI) 0.46 to 1.63; one trial; P = 0.66) or in event-free survival (HR 0.86, 95% CI 0.50 to 1.49; one trial; P = 0.59). We calculated the HR values using the complete follow-up period of the trial. The study also reported overall survival estimates at a fixed point in time. At the time point of five years, the survival estimate was reported to be 59% for the retinoic acid group and 41% for the no-further-therapy group (P value not reported). We did not identify results for treatment-related mortality, progression-free survival, early or late toxicity, or health-related quality of life. We could not rule out the possible presence of selection bias, performance bias, attrition bias, and other bias. We judged the evidence to be of low quality for overall survival and event-free survival, downgraded because of study limitations and imprecision.

AUTHORS' CONCLUSIONS

We identified one RCT that evaluated additional retinoic acid as part of a postconsolidation therapy after HDCT followed by autologous HSCT versus no further therapy in people with high-risk neuroblastoma. There was no clear evidence of a difference in overall survival and event-free survival between the treatment alternatives. This could be the result of low power. Information on other outcomes was not available. This trial was performed in the 1990s, since when many changes in treatment and risk classification have occurred. Based on the currently available evidence, we are therefore uncertain about the effects of retinoic acid in people with high-risk neuroblastoma. More research is needed for a definitive conclusion.

Patients in pediatric phase I and early phase II clinical oncology trials at Gustave Roussy: a 13-year center experience

In the European Union, the pediatric medicines regulation in 2007 modified significantly the access to new agents in pediatric oncology. Early oncology trials are still thought to be associated with limited benefit and substantial risk. We report the characteristics and outcome of patients below 21 years enrolled in investigational trials in the Pediatric and Adolescent Department at Gustave Roussy between January 2000 and December 2012. A total of 235 patients (median age, 10.4 [0.8 to 20.7] y) were included in 26 trials (16 cytotoxic and 10 targeted agents) for a total of 260 inclusions. A total of 117 patients (50%) had brain tumors and 68 (29%) had various soft tissue and bone sarcoma. Thirteen of the 106 patients in a phase I trial experienced dose-limiting toxicity. Main severe toxicity was hematologic; none had toxic death. Grade 3 to 4 toxicities were associated with combination trials, cytotoxic agent, and at least 1 previous line of therapy. Thirty patients (12%) had objective response and 42 (16%) had stable disease for >4 months. Median overall survival was 9.0 months (95% CI, 7.5-10.5) and 73% of patients received further anticancer treatment. Phase I to II pediatric oncology trials are safe, associated with clinical benefit, and can be successfully integrated in current relapse strategies.

Retinoic acid post consolidation therapy for high-risk neuroblastoma patients treated with autologous hematopoietic stem cell transplantation

BACKGROUND

Neuroblastoma is a rare malignant disease and mainly affects infants and very young children. The tumors mainly develop in the adrenal medullary tissue and an abdominal mass is the most common presentation. About 50% of patients have metastatic disease at diagnosis. The high-risk group is characterized by metastasis and other characteristics that increase the risk for an adverse outcome. High-risk patients have a five-year event-free survival of less than 50%. Retinoic acid has been shown to inhibit growth of human neuroblastoma cells and has been considered as a potential candidate for improving the outcome of patients with high-risk neuroblastoma.

OBJECTIVES

To evaluate efficacy and adverse events of retinoic acid after consolidation with high-dose chemotherapy followed by bone marrow transplantation as compared to placebo or no therapy in patients with high-risk neuroblastoma (as defined by the International Neuroblastoma Risk Group (INRG) classification system). Our outcomes of interest were overall survival and treatment-related mortality as primary outcomes; and progression- and event-free survival, early and late toxicity, and health-related quality of life as secondary outcomes.

SEARCH METHODS

We searched the electronic databases CENTRAL (2014, Issue 8) on The Cochrane Library, MEDLINE (1946 to October 2014), and EMBASE (1947 to October 2014). Further searches included trial registries, conference proceedings, and reference lists of recent reviews and relevant articles. We did not apply limits on publication year or languages.

SELECTION CRITERIA

Randomized controlled trials (RCTs) evaluating retinoic acid post consolidation therapy for high-risk neuroblastoma patients treated with autologous hematopoietic stem cell transplantation (HSCT) compared to placebo or no further treatment.

DATA COLLECTION AND ANALYSIS

Two review authors performed the study selection, extracted the data on study and patient characteristics and assessed the risk of bias independently. We resolved differences by discussion or by appeal to a third review author. We performed analyses according to the guidelines of the Cochrane Handbook for Systematic Reviews of Interventions. The authors of the included study did not report the results specifically for the treatment groups relevant to this Cochrane Review. Therefore, we deduced the appropriate survival data from the published survival curves and calculated a hazard ratio (HR) based on the deduced data.

MAIN RESULTS

We identified one RCT (CCG-3891) that included patients with high-risk neuroblastoma who received high-dose chemotherapy followed by autologous HSCT (N = 98) after a first random allocation and who received retinoic acid (13-cis-retinoic acid; N = 50) or no further therapy (N = 48) after a subsequent second random allocation. These patients had no progressive disease after consolidation therapy. There was no clear evidence of difference between the treatment groups in both overall survival (HR 0.87, 95% CI 0.46 to 1.63; one trial; P = 0.66, low quality of evidence) and event-free survival (HR 0.86, 95% CI 0.50 to 1.49; one trial; P = 0.59, low quality of evidence). We calculated these HR values using the complete follow-up period of the trial. The study also reported five-year overall survival rates: 59% for the retinoic acid group and 41% for the no further therapy group (P value not reported). We did not identify results for treatment-related mortality, progression-free survival, early or late toxicity, or health-related quality of life. Also, we could not rule out the possible presence of selection bias, performance bias, attrition bias, and other bias.

AUTHORS' CONCLUSIONS

We identified one RCT that evaluated retinoic acid as a consolidation therapy versus no further therapy after high-dose chemotherapy followed by bone-marrow transplantation in patients with high-risk neuroblastoma. The difference in overall survival and event-free survival between both treatment alternatives was not statistically significantly different. This could be the result of low power. Information on other outcomes was not available. This trial was performed in the 1990s, since then many changes in for example treatment and risk classification have occurred. Therefore, based on the currently available evidence, we are uncertain about the effects of retinoic acid in patients with high-risk neuroblastoma. More research is needed for a definitive conclusion.

Docetaxel in the treatment of children with refractory or relapsed hepatoblastoma

We report on the use of single-agent docetaxel (100 mg/m(2) in children >10 kg, 3.3 mg/kg in children <10 kg), given as a 1-hour infusion at 21-day intervals in 5 children with relapsed or refractory hepatoblastoma. One patient achieved complete remission of pulmonary metastases after 2 courses of docetaxel and remains well 10 years later, after completion of 13 courses of docetaxel and whole-lung radiotherapy. One patient showed a partial response to docetaxel based on α-fetoprotein measurements. Docetaxel shows some activity in progressive hepatoblastoma in this small case series and is a potential drug for future study in this disease.

Pediatric multifocal glioblastoma multiforme with fulminant course

Glioblastoma multiforme (GBM) is the most common primary malignant brain tumor. GBM in children is less common than in adults and has a better prognosis. Pediatric GBM is a rare entity, and a multifocal development in a pediatric GBM is much rarer. We report to you one such rare case of pediatric multifocal GBM in a 5-year-old child who developed rapidly increasing multiple lesions after radiotherapy. More studies are required to study the genetic analysis, tumor behavior, management and outcome of these rare tumors.

Remission re-induction chemotherapy with clofarabine, topotecan, thiotepa, and vinorelbine for patients with relapsed or refractory leukemia

BACKGROUND

We determined the maximum tolerated dose (MTD) of clofarabine when administered with topotecan, vinorelbine, thiotepa, and dexamethasone (TVTC) for children with relapsed or refractory acute leukemia, and observed the efficacy and toxicities of this therapy.

PROCEDURE

Twelve patients with acute lymphoblastic or myeloblastic leukemia were given a 14-day remission induction therapy. Clofarabine was administered at a dose of 30 or 40 mg/m(2)/day over 2 hr for five consecutive days in six patients each. Patients who achieved a remission proceeded to a stem cell transplant (HSCT). A second cycle could be administered prior to HSCT.

RESULTS

Of the six patients at the 30 mg/m(2) clofarabine dose, two achieved a complete response (CR) and one a PR and proceeded to BMT. Three patients had progressive disease. Five of the six patients at the 40 mg/m(2) achieved a CR. Four proceeded to HSCT, and one relapsed prior to HSCT. One patient died on day 45 with marrow hypoplasia without evidence of leukemia. Hematologic and infectious adverse events were universal. The one dose limiting non-infectious toxicity observed was prolonged marrow hypoplasia.

CONCLUSION

TVTC has significant anti-leukemic activity in both acute lymphoblastic and myeloblastic leukemia. The MTD of clofarabine is 40 mg/m(2)/day in this combination. This is the recommended dose for the phase II study in patients with refractory or relapsed leukemia, a population which has limited therapeutic options.

Salvage chemotherapy for metastatic and recurrent ependymoma of childhood

INTRODUCTION

Chemotherapy has limited role in the up-front management of ependymoma. At the time of recurrence, the role of chemotherapy is also ill defined and the choice of chemotherapeutic agents is often arbitrary, based on anecdotal data and personal experience.

METHODS

The purpose of this review is to describe and critically analyze the published literature on chemotherapy in patients with recurrent and metastatic ependymoma.

DISCUSSION

The disappointing response rate with single agents (12.9%) and combinations (17.4%) emphasizes the need to re-evaluate the current chemotherapeutic approach of intracranial ependymoma, and biological studies are needed to identify targets that may be considered for clinical trials.

Good clinical practice and the conduct of clinical studies in pediatric oncology

This article discusses the principles that guide good clinical practice standards, with particular emphasis on how they to relate to pediatric oncology research and recent efforts at harmonization. The authors review the clinical trials process and the roles of the participants, highlighting the pivotal role of the clinical investigator and the research team, and briefly review the historical aspects of drug development regulations in the United States and the current regulatory paths for pediatric oncology drug development. Where relevant, historical events that underlie many of the regulations and their current applications are described, and practical examples are provided.

Clofarabine induced durable complete remission in heavily pretreated adolescents with relapsed and refractory leukemia

Current treatments for relapsed/refractory leukemias are unable to achieve extended remissions in most patients even with multiagent chemotherapy. Clofarabine is a new nucleoside analog that has demonstrated clinical benefit in phase I-II studies, and is currently being studied in children and adults with leukemias and has been approved for the treatment of children with relapsed or refractory acute lymphocytic leukemia. We report the experience of three adolescents, two with acute lymphocytic leukemia in 3rd relapse and one with relapsed/refractory acute myeloid leukemia, who achieved complete remission with clofarabine. The remissions were sustained with repeated cycles of monotherapy for 47, 59, and 64 weeks, respectively.

A process to facilitate decision making in pediatric stem cell transplantation: the individualized care planning and coordination model

Providers of care for children undergoing stem cell transplantation (SCT) skillfully combine the roles of scientist and clinician. As scientists, they apply scientific methods and disease theory in the creation and testing of new therapies and in the careful observation and exploration of treatment outcomes. As clinicians, they are capable of intuitively delivering care in a patient- and family-centered context of meaning and life values. The specialty of SCT has inherent aspects that make treatment decision making complex and potentially contentious. Having a strategy ready to implement in advance or at the time when treatment decisions need to be made will facilitate and enhance the decision making process for both the health care team and family members. Here we introduce the individualized care planning and coordination (ICPC) model as a practical approach to facilitate ethical and effective decision making in pediatric SCT settings. The ICPC is a 3-step model comprising (1) relationship--understanding the illness experience from the perspective of the patient and family, sharing relevant information, and assessing ongoing needs; (2) negotiation--prognosticating, establishing goals of care, and discussing treatment options; and (3) plan--generating a comprehensive plan of care that includes life and medical plans. Based on a foundation of a care of competence, empathy, compassion, communication, and quality, the ICPC model aims to diminish contentious family-staff interactions that can lead to mistrust and help guide treatment decision making. The ICPC model enhances communication among patients, families, and clinicians by revealing patient and family values and medical and quality-of-life priorities before reaching or even during critical decision points in the transplantation process.

Phase II study of gemcitabine in children with solid tumors of mesenchymal and embryonic origin

The therapeutic benefit and side-effect profile of gemcitabine in adults with relapsed solid tumors is well known. So far, few data are available about its significance in pediatric relapsed solid tumors. To determine the efficacy and tolerability of gemcitabine in children, the drug was administered by intravenous short-term infusion over 30 min at a dose of 1200 mg/m2 weekly for 3 weeks as one cycle in children with relapsed solid tumor of embryonic or mesenchymal origin. From May 2003 to September 2004, 14 male and six female patients (2-23, median 15.8 years) were recruited for this prospective open-label phase II study (two-step Simon design). The patients suffered from rhabdomyosarcoma (n=8), Ewing's sarcoma (n=4), osteosarcoma (n=2), neuroblastoma (n=3), hepatoblastoma (n=2) and nephroblastoma (n=1). Median duration of therapy was 27.5 days (7-99), corresponding to 4.0 (2-11) infusions of gemcitabine. Two patients (neuroblastoma and Ewing) had stable disease documented for 69 and 70 days, whereas no objective responses were observed. In 34/94 administered infusions; doses had to be reduced or omitted for grade 3-4 hematotoxicity. Minimal activity was observed in this cohort of children with a wide spectrum of mesenchymal and embryonic tumors. Given the relatively low dose of gemcitabine administered, this study does not exclude the possibility of activity at higher doses. Secondly, the tolerability of gemcitabine in children was consistent with that expected in adults. For further studies in this population, we recommend the use of gemcitabine in combination with other agents.

Phase II study of clofarabine in pediatric patients with refractory or relapsed acute lymphoblastic leukemia

PURPOSE

To evaluate the efficacy and safety of clofarabine, a novel deoxyadenosine analog, in pediatric patients with refractory or relapsed acute lymphoblastic leukemia (ALL).

PATIENTS AND METHODS

In a phase II, open-label, multicenter study, 61 pediatric patients with refractory or relapsed ALL received clofarabine 52 mg/m2 intravenously over 2 hours daily for 5 days, every 2 to 6 weeks. The median age was 12 years (range, 1 to 20 years), and the median number of prior regimens was three (range, two to six regimens).

RESULTS

The response rate was 30%, consisting of seven complete remissions (CR), five CRs without platelet recovery (CRp), and six partial remissions. Remissions were durable enough to allow patients to proceed to hematopoietic stem-cell transplantation (HSCT) after clofarabine. Median CR duration in patients who did not receive HSCT was 6 weeks, with four patients maintaining CR or CRp for 8 weeks or more (8+, 12, 37+, and 48 weeks) on clofarabine therapy alone. The most common adverse events of grade > or = 3 were febrile neutropenia, anorexia, hypotension, and nausea.

CONCLUSION

Clofarabine is active as a single agent in pediatric patients with multiple relapsed or refractory ALL. The toxicity profile is as expected in this heavily pretreated patient population. Studies exploring rational combinations of clofarabine with other agents are ongoing in an effort to maximize clinical benefit.

[Patients' rights during medical research and specifics in oncology (in France)]

PURPOSE

Clinical research in oncology is part of the care, instead of being theoretical, because it can offer new drugs to patients who are suffering from severe illnesses, but also because it offers better practices. The vulnerability of patients suffering from cancers, at each stage of the disease, requires special protection. Because of its multiple aspects, clinical research in oncology asks ethical questions. Medical deontology and laws, national and supranational, allow research with respect to the subject. The present article reviews these texts.

CURRENT KNOWLEDGE AND KEY POINTS

The rights of the person involved in clinical trials essentially consist of information and consent, but also the right to refuse, and the confidentiality of data collected. More subtle rights are now emerging because of new technologies, such as genetics. One of them is the right to be protected as a member of the human race, which is in continuity with human rights.

FUTURE AND PROJECTS

Finally, medical responsibility during research is increasing. It responds to the right of each person to see that his dignity is respected, although this dignity may be difficult to define. One of the more pertinent questions in building 'evidence-based ethics' concerns research into the evaluation by the persons themselves involved in the research.

Chemotherapy for intramedullary spinal cord tumors

Intramedullary tumors are rare, accounting for only about 4% of all CNS neoplasms. Although surgery represents the most effective treatment, recurrence may occur. As a large proportion of intramedullary malignancies occur in children, who are more sensitive to the deleterious effects of irradiation, chemotherapy assumes an important role. This article describes the most common intramedullary tumors and the role of chemotherapy.

Oral methotrexate for recurrent brain tumors in children: a Pediatric Oncology Group study

PURPOSE

Children with recurrent or progressive central nervous system (CNS) tumors have an unfavorable prognosis. Based on Pediatric Oncology Group (POG) institutional pilot data, low-dose oral methotrexate (MTX) was studied.

METHODS

Eight dosages of MTX 7.5 mg/m2 every 6 hours were administered on a weekly schedule for as long as 18 months. Patients in six different brain tumor strata were accrued.

RESULTS

The response rates (complete or partial responses) were as follows: astrocytoma 2 of 10, malignant glioma 1 of 19, medulloblastoma 0 of 18, brainstem tumor 0 of 12, ependymoma 1 of 7, and miscellaneous histologic types 0 of 12. The main toxicities, mucositis, myelosuppression, and hepatic transaminase elevation were considered tolerable.

CONCLUSION

Low-dose oral MTX showed no significant activity against malignant glioma, medulloblastoma, brainstem tumors, and miscellaneous histologic types. Indeterminate but low response rates were observed in children with astrocytoma and ependymoma. This regimen will not be recommended for front-line therapy.

Phase I therapy trials in children with cancer

PURPOSE

This study examined the response and toxicity rates of antineoplastic drugs evaluated in phase I clinical trials in children to identify trends in response and toxicity over time.

PATIENTS AND METHODS

Full length, peer-reviewed articles describing the results of single agent phase I therapy trials in children younger than 21 years with cancer were reviewed. Tumor-specific response data and doses of drugs that resulted in objective responses were noted. Deaths that occurred on study caused by drug toxicity, progressive disease (PD), or complications of marrow aplasia were identified, along with drug doses that resulted in toxic death. Temporal trends in response rates, toxicity, and number of patients entered in trials were examined.

RESULTS

A total of 1,606 patients with cancer were enrolled in 56 single-agent pediatric phase I therapy trials published between 1978 and 1996. Of these, 1,257 were evaluated for response by tumor type. The overall objective response rate was 7.9%. Response rates were highest for patients with neuroblastoma (17.7%) and acute myelogenous leukemia (11.6%). Patients with osteosarcoma and rhabdomyosarcoma had response rates of < 3%. Sixty percent of responses in patients with solid tumors occurred at 81 to 100% of the maximum tolerated dose (MTD), although 42% of responses in patients with leukemia occurred at > 100% of the MTD. Death on study was noted in 7.0% of all patients entered in trials. Only 0.7% of patients experienced a death related to drug toxicity. PD accounted for the death of 5.6% of study participants. A trend of increasing response rate despite smaller trial size was noted over the last 7 years of this period.

CONCLUSION

Phase I trials in children with cancer represent a safe mechanism to determine the MTD, toxicity profile, and pharmacokinetics of new agents for use in children with cancer.

Chemotherapy in recurrent ependymoma

Surgical resection with or without radiation therapy confers long-term remission in approximately half of the patients newly diagnosed with ependymoma. Chemotherapy has a limited role in the management of ependymoma. In newly diagnosed infants, chemotherapy is utilized as an attempt to defer radiation. The use of chemotherapy in older children has provided no conclusive benefit. The largest experience with chemotherapy in ependymoma has been in children with recurrent disease. In this section, we will analyze the principal institutional and cooperative group phase I, phase II, and phase III clinical trials utilizing single-agent and multiagent chemotherapy in patients with recurrent ependymoma. In addition, future directions relating to novel medical oncologic therapies will also be discussed.