Topotecan for the treatment of recurrent or progressive central nervous system tumors - a pediatric oncology group phase II study

Childhood medulloblastoma

Medulloblastoma accounts for 15-20% of childhood nervous system tumours. The risk of dying was reduced by 30% in the last twenty years. Patients are divided in risk strata according to post-surgical disease, dissemination, histology and some molecular features such as WNT subgroup and MYC status. Sixty to 70% of patients older than 3 years are assigned to the average-risk group. High-risk patients include those with disseminated and/or residual disease, large cell and/or anaplastic histotypes, MYC genes amplification. Current and currently planned clinical trials will: (1) evaluate the feasibility of reducing both the dose of craniospinal irradiation and the volume of the posterior fossa radiotherapy (RT) for those patients at low biologic risk, commonly identified as those having a medulloblastoma of the WNT subgroup; (2) determine whether intensification of chemotherapy (CT) or irradiation can improve outcome in patients with high-risk disease; (3) find target therapies allowing tailored therapies especially for relapsing patients and those with higher biological risk.

Survival After Relapse of Medulloblastoma

Survival after recurrence of medulloblastoma has not been reported in an unselected cohort of patients in the contemporary era. We reviewed 55 patients diagnosed with medulloblastoma between 2000 and 2010, and treated at Seattle Children's Hospital to evaluate patterns of relapse treatment and survival. Fourteen of 47 patients (30%) over the age of 3 experienced recurrent or progressive medulloblastoma after standard therapy. The median time from diagnosis to recurrence was 18.0 months (range, 3.6 to 62.6 mo), and site of recurrence was metastatic in 86%. The median survival after relapse was 10.3 months (range, 1.3 to 80.5 mo); 3-year survival after relapse was 18%. There were trend associations between longer survival and having received additional chemotherapy (median survival 12.8 vs. 1.3 mo, P=0.16) and radiation therapy (15.4 vs. 5.9 mo, P=0.20). Isolated local relapse was significantly associated with shorter survival (1.3 vs. 12.8 mo, P=0.009). Recurrence of medulloblastoma is more likely to be metastatic than reported in previous eras. Within the limits of our small sample, our data suggest a potential survival benefit from retreatment with cytotoxic chemotherapy and radiation even in heavily pretreated patients. This report serves as a baseline against which to evaluate novel therapy combinations.

An integrated in vitro and in vivo high-throughput screen identifies treatment leads for ependymoma

Using a mouse model of ependymoma-a chemoresistant brain tumor-we combined multicell high-throughput screening (HTS), kinome-wide binding assays, and in vivo efficacy studies, to identify potential treatments with predicted toxicity against neural stem cells (NSC). We identified kinases within the insulin signaling pathway and centrosome cycle as regulators of ependymoma cell proliferation, and their corresponding inhibitors as potential therapies. FDA approved drugs not currently used to treat ependymoma were also identified that posses selective toxicity against ependymoma cells relative to normal NSCs both in vitro and in vivo, e.g., 5-fluorouracil. Our comprehensive approach advances understanding of the biology and treatment of ependymoma including the discovery of several treatment leads for immediate clinical translation.

A phase II study of metronomic oral topotecan for recurrent childhood brain tumors

BACKGROUND

The prognosis for recurrent or refractory brain tumors in children is poor with conventional therapies. Topotecan is a topoisomerase I inhibitor with good central nervous system (CNS) penetration following oral administration. Increased efficacy of topotecan has been demonstrated with prolonged low-dose daily treatment in pre-clinical models. To investigate further this drug delivered orally in pediatric CNS malignancies, a phase II study in children with recurrent or refractory brain tumors was performed.

PROCEDURE

Patients ≤ 21 years of age at diagnosis with a recurrent, progressive, or refractory primary CNS malignancy and measurable disease, were eligible. Patients enrolled into four strata: ependymoma (N = 4), high-grade glioma (HGG) (N = 6), brainstem glioma (BSG) (N = 13), and primitive neuroectodermal tumor (PNET) (N = 8). Oral topotecan was administered once daily at a dose of 0.8 mg/m(2)/day for 21 consecutive days repeated every 28 days. Response and toxicity profiles were evaluated.

RESULTS

Twenty-six patients were evaluable (median age 9.2 years; 10 males). Two objective responses were observed in PNET patients with disseminated tumor at study entry. These two patients remain alive and in remission 7 and 9.5 years off study. Four other patients (two BSG, one PNET, and one HGG) had stable disease (median 4.6 months). The most common toxicities were hematologic.

CONCLUSIONS

Daily oral topotecan at a dose of 0.8 mg/m(2)/day can be safely administered to children with recurrent or refractory brain tumors. This regimen identified activity in recurrent PNET. The prolonged progression free survival (PFS) in two PNET patients justifies consideration of this regimen in more advanced clinical trials.

Childhood medulloblastoma

Among all the childhood central nervous system tumours, medulloblastoma and other neuroectodermal tumours account for 16-25% of cases. The causative factors of medulloblastoma/PNET have not been well established. It is more frequent in boys than in girl and in children than in adults. There was a significant improvement of survival for children diagnosed in 2000-2002 compared to those diagnosed in 1995-1999. The risk of dying was reduced by 30%. Patients are generally divided into risk-stratified schemes on the basis of age, the extent of residual disease, and dissemination. Sixty to 70% of patients older than 3 years are assigned to the average-risk group. High-risk patients include those in the disseminated category, and in North American trials those that have less than a gross or near-total resection, which is arbitrarily defined as 1.5 cm(2) of post-operative residual disease. Current and currently planned clinical trials will:define molecular and biological markers that improve outcome prediction in patients with medulloblastoma and which can be incorporated for front-line stratification of newly defined risk subgroups.

Lack of efficacy of bevacizumab plus irinotecan in children with recurrent malignant glioma and diffuse brainstem glioma: a Pediatric Brain Tumor Consortium study

PURPOSE

A phase II study of bevacizumab (BVZ) plus irinotecan (CPT-11) was conducted in children with recurrent malignant glioma (MG) and intrinsic brainstem glioma (BSG).

PATIENTS AND METHODS

Eligible patients received two doses of BVZ intravenously (10 mg/kg) 2 weeks apart and then BVZ plus CPT-11 every 2 weeks until progressive disease, unacceptable toxicity, or a maximum of 2 years of therapy. Correlative studies included diffusion weighted and T1 dynamic contrast-enhanced permeability imaging, BVZ pharmacokinetics, and estimation of vascular endothelial growth factor receptor 2 (VEGFR-2) phosphorylation in peripheral blood mononuclear cells (PBMC) after single-agent BVZ.

RESULTS

Thirty-one evaluable patients received a median of two courses of BVZ plus CPT-11 (range, 1 to 19). No sustained responses were observed in either stratum. Median time to progression for all 34 eligible patients enrolled was 127 days for MG and 71 days for BSG. Progression-free survival rates at 6 months were 41.8% and 9.7% for MG and BSG, respectively. Toxicities related to BVZ included grade 1 to 3 fatigue in seven patients, grade 1 to 2 hypertension in seven patients, grade 1 CNS hemorrhage in four patients, and grade 4 CNS ischemia in two patients. The mean diffusion ratio decreased after two doses of BVZ in patients with MG only. Vascular permeability parameters did not change significantly after therapy in either stratum. Inhibition of VEGFR-2 phosphorylation in PBMC was detected in eight of 11 patients after BVZ exposure.

CONCLUSION

BVZ plus CPT-11 was well-tolerated but had minimal efficacy in children with recurrent malignant glioma and brainstem glioma.

Childhood medulloblastoma: current status of biology and treatment

Medulloblastoma, a primitive neuro-ectodermal tumour that arises in the posterior fossa, is the most common malignant brain tumour occurring in childhood. Over the past half century, the long-term survival for children with medulloblastoma has improved remarkably from a certain fatal diagnosis to a cancer that is often curable. Although overall survival for children with non-disseminated and non-anaplastic medulloblastoma can approach 80%, the current multidisciplinary therapeutic approach is not without long-term sequelae. Chemotherapy has improved the long-term survival and allowed for reductions in the amount of radiation given, thereby reducing some of the long-term toxicities. In this review, we describe the current understanding of the basic biology of medulloblastoma and report on the current active chemotherapeutic agents utilized in medulloblastoma therapy. Ultimately, our understanding of the basic biology of medulloblastoma may lead to further advances in therapy by providing targets that are more specific and potentially less toxic.

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.

Myeloablative chemotherapy with autologous bone marrow rescue in children and adolescents with recurrent malignant astrocytoma: outcome compared with conventional chemotherapy: a report from the Children's Oncology Group

PURPOSE

Children and adolescents with malignant astrocytomas recurring after initial treatment have a dismal prognosis, with only rare patients surviving 1-year beyond recurrence. The purpose of this study was to attempt to improve their survival.

METHODS

Twenty-seven children and adolescents with malignant astrocytomas [17 glioblastoma multiforme and 10 anaplastic astrocytoma (AA)] following initial tumor progression, received myeloablative chemotherapy followed by autologous marrow rescue with one of three thiotepa and etoposide-based chemotherapy regimens, administered alone (n = 11) or combined with carmustine (n = 5) or carboplatin (n = 11). Time to progression and death following myeloablative chemotherapy for these patients was compared non-randomly with outcome of a contemporaneously treated cohort of similar patients who received only conventional chemotherapy following initial tumor progression. The two cohorts were compared for age, histology, prior therapies, extent of surgical resection at progression, and time from initial diagnosis to progression.

RESULTS

Five of 27 children (two with glioblastoma multiforme and three with AA) survive event-free from 8.3 to 13.3 years (median of 11.1 years) following myeloablative chemotherapy. Of 56 children with recurrent malignant astrocytoma who received conventional chemotherapy following initial progression, no patient survives. Differences in distributions of survival were not significant when stratified by surgical debulking (P = 0.39). However, for patients who were surgically debulked, the survival distributions are significantly different (P = 0.017).

CONCLUSIONS

Myeloablative chemotherapy with autologous marrow rescue can produce durable remissions in children and young adults with recurrent malignant gliomas, in the setting of minimal residual tumor burden achieved surgically.

Dose intensive melphalan and cyclophosphamide with autologous hematopoietic stem cells for recurrent medulloblastoma or germinoma

PURPOSE

To determine the response, toxicity, and survival for children with progressive or recurrent medulloblastoma and germinoma using a single myeloablative course of chemotherapy supported by autologous hematopoietic stem cells.

PATIENTS AND METHODS

Subjects were in second remission or had minimal residual disease at the time of study entry. The conditioning regimen consisted of cyclophosphamide 6,000 mg/m(2) plus melphalan 180 mg/m(2).

RESULTS

Twenty-nine evaluable pediatric patients were accrued. The most frequent major toxicities were myelosuppression, infections, and stomatitis, but no toxic deaths were recorded. Best responses were: CR = 6, CCR = 13, PR = 6, SD = 2, and PD = 2. There were 6 medulloblastoma and 3 germinoma survivors with a median follow-up of 7.5 years (range = 2.8-10). Two germinoma survivors received radiotherapy after autografting for presumptive progressive disease.

CONCLUSION

Myeloablative chemotherapy consisting of cyclophosphamide and melphalan was tolerable in the relapsed brain tumor setting with 19/29 cases achieving CR or CCR status and 9/29 becoming long-term survivors.

Ependymoma

Ependymomas are rare tumours of neuroectodermal origin classified as myxopapillary ependymoma and subependymoma (grade I), ependymoma (grade II) and anaplastic ependymoma (grade III). The more common location is infratentorial (60%). Age <40 years and extent of surgery appear related to better prognosis, while the role of other prognostic factors, such as tumour grade and tumour site are equivocal. This emphasizes the role of surgery as the standard treatment. Postoperative radiotherapy is indicated in high-grade ependymomas, and is recommended in low-grade ependymomas after subtotal or incomplete resection (confirmed by postoperative MR). Deferral of radiotherapy until recurrence may be considered on an individual basis for patients with MR confirmation of a radical resection. Recommended dose to involved fields is 45-54 Gy for low-grade (grade II) and 54-60 Gy for high-grade ependymomas (grade III). There is no proof that postoperative chemotherapy improves the outcome. At recurrence, platinum-, nitrosourea- or temozolomide-based chemotherapy can be administered, although there is no evidence of efficacy.

One- and two-stage designs for phase II window studies

The primary goal of phase II window studies in cancer is testing new single agents or combination therapies for newly diagnosed patients who are less likely to have multiple-drug-resistant tumours than the typical phase II patients who have failed one or more chemotherapeutic regimens. In addition, by utilizing newly diagnosed patients, one can assess the responsiveness in a population more representative of where the phase II agent might be applied in a true phase III setting. In general, the outcome of a patient on a phase II window study can be categorized as response, stable disease, or early disease progression. Phase II window studies sometimes require early stopping rules for both insufficient response rate and excessive early progression rates. In this paper, one-stage and two-stage designs for phase II window studies are developed, requiring the monitoring of two rates. It is shown that the power function is monotone in response rate and early disease progression rate. Consequently, the significance level and power are easy to compute. Computational procedures are described and examples are provided. The proposed method can be applied to other studies with categorical outcomes.

Efficacy of vincristine and etoposide with escalating cyclophosphamide in poor-prognosis pediatric brain tumors

The objective of this study was to assess the efficacy of the VETOPEC regimen, a regimen of vincristine and etoposide with escalating doses of cyclophosphamide (CPA), in pediatric patients with high-risk brain tumors. Three consecutive studies by the Australia and New Zealand Children's Cancer Study Group--VETOPEC I, Baby Brain 91, and VETOPEC II--have used a specific chemotherapy regimen of vincristine (VCR), etoposide (VP-16) and escalating CPA in patients with relapsed, refractory, or high-risk solid tumors. Patients in the VETOPEC II cohort were treated with very high dose CPA with peripheral blood stem cell (PBSC) rescue. We analyzed the subset of patients with high-risk brain tumors treated with these intensive VETOPEC-based protocols to assess the response, toxicity, and survival. We also assessed whether the use of very high dose chemotherapy with stem cell rescue improved the response rate or affected toxicity. Seventy-one brain tumor patients were treated with VETOPEC-based protocols. Of the 54 patients evaluable for tumor response, 17 had a complete response (CR) and 20 a partial response (PR) to treatment, which yielded an overall response rate of 69%. The CR + PR was 83% (19/23) for medulloblastomas, 56% (5/9) for primitive neuroectodermal tumors, 55% (6/11) for grade 3 and 4 astrocytomas, and 80% (6/8) for ependymomas. At a median follow-up of 36 months, overall survival for the entire cohort of 71 patients was 32%, with event-free survival of 13%. There were no toxic deaths within the PBSC-supported VETOPEC II cohort, despite higher CPA doses, compared with 7% among the non-PBSC patients. This regimen produces high response rates in a variety of very poor prognosis pediatric brain tumors. The maximum tolerated dose of CPA was not reached. Higher escalation in doses of CPA did not deliver a further improvement in response. With PBSC rescue in the VETOPEC II study, hematologic toxicity was no longer a limiting factor. The response rates observed support further development of this chemotherapy regimen.

Considerations on the Role of Chemotherapy and Modern Radiotherapy in the Treatment of Childhood Low Grade Glioma

The treatment of childhood low grade glioma (LGG), if not amenable to complete resection, quite often is a relevant clinical challenge. LGG in many instances are indeed slow growing tumors, which, if not controlled, can cause severe morbidity and ultimately jeopardize life. Most of the time children bearing an unresectable LGG can be considered affected by a chronic disease, deserving protracted cures. The treatment philosophy, which has dictated the treatment of malignant cancers, has also inspired the therapeutic concepts for managing childhood LGG. However, it is getting more and more evident that different strategies are needed for them. LGG represent a highly heterogeneous group of neoplasm and comprehensive treatment concepts rarely meet the individual patient's needs. After more than 20 years of clinical research it can be stated with confidence that for unresectable, progressive LGG, chemotherapy (CT) represents an effective treatment modality. It delays tumor growth and postpones the use of radiotherapy (RT), thus sparing the deleterious effects of irradiation on a developing brain. However, CT rarely cures LGG and definitively obviates the need of RT or aggressive surgery. Furthermore, little is known on the actual impact of CT on patients' overall health status. Recent progresses in RT delivering techniques, which allow reducing the safety margins, are tempering the concerns related to the use of this treatment modality in children. This manuscript reviews and expands these data, trying to combine them in a coherent picture that it is hoped can help in directing future research in this field.

Open-label simultaneous radio-chemotherapy of glioblastoma multiforme with topotecan in adults

BACKGROUND

Due to its radioresistance, the prognosis of glioblastoma multiforme (GBM) remains poor. Therefore, we investigated the impact of simultaneous radio-chemotherapy with topotecan (Hycamtin) on clinical outcome, tolerability and quality of life.

PATIENTS AND METHODS

In this multicenter trial, 60 patients (19 females, 41 males) with histologically proven (5x biopsy, 31x subtotal resection, 24x total resection) GBM were included. Radio-Chemotherapy was performed with daily doses of 2.0 Gy (total, 60 Gy), and 0.5 mg (absolute dose) of topotecan intravenously 1 h prior to irradiation. Toxicity was assessed using common toxicity criteria (CTC). General condition and quality of life were assessed at baseline, at the end of therapy, and 6 weeks post-therapy. Local control and length of survival were compared with an historical control group of 67 patients only treated with postoperative radiotherapy following stereotactic biopsy (15x), subtotal resection (39x), or total resection (13x).

RESULTS

57 patients completed the therapy. Median radiation dose was 60 Gy (range 16-76 Gy). Median cumulative topotecan dose was 15 mg (range 7.5-18.5 mg). CTC toxicity grade 3 was observed in six patients and grade 4 toxicity in two patients (three events). Two patients died of septic disease. Mean Karnofsky index was 87% at baseline, 81% at the end of therapy, and 80% at 6 weeks post-therapy. Median survival time was 15 months, significantly longer than the 11 months seen in the control group (P < 0.002). Extent of tumour resection or patient age did not have a significant effect on survival.

CONCLUSION

This multimodal approach is well tolerated, and quality of life remains preserved. The relatively long median survival time is promising but a further randomised double blind placebo controlled parallel designed clinical trial should be performed to confirm these results.

A multicenter retrospective study of chemotherapy for recurrent intracranial ependymal tumors in adults by the Gruppo Italiano Cooperativo di Neuro-Oncologia

BACKGROUND

No data on the role of chemotherapy in recurrent ependymal tumors are available in adults. The aim of the current study was to investigate outcomes after salvage chemotherapy in this setting.

METHODS

A retrospective review was made of the charts of 28 adults (> or = 18 years) with progressive or recurrent ependymal tumors after surgery and radiotherapy, who received chemotherapy between 1993 and 2003 in 3 institutions of the Gruppo Italiano Cooperativo di Neuro-Oncologia network.

RESULTS

Thirteen patients (46.3%) received cisplatin-based chemotherapy (Group A) and 15 (53.7%) received regimens without cisplatin (Group B). Platinum-based chemotherapy yielded 2 complete responses (CR) (15.4%) and 2 (15.4%) partial responses (PR), whereas 7 patients (53.8%) remained stable (SD). After regimens without cisplatin, there were no CR, 2 PR (13.3%), and 11 SD (73.3%). The overall median time to progression was 9.9 months (95% confidence interval [95% CI], 7.5-21.7 months), 9.9 months (5.2-not reached) for Group A and 10.9 months (95% CI, 7.17-23.9 months) for Group B. The overall median survival (OS) was 40.7 months (95% CI, 16-not reached), 31 months (21-not reached) for Group A and 40.7 months (13.4-not reached) for Group B.

CONCLUSIONS

Cisplatin-based chemotherapy achieved a higher response rate, but did not prolong disease progression-free survival or OS. More active regimens for the salvage treatment of ependymal tumors have yet to be found.

Response to paclitaxel, topotecan, and topotecan-cyclophosphamide in children with untreated disseminated neuroblastoma treated in an upfront phase II investigational window: a pediatric oncology group study

PURPOSE

Most children older than 1 year of age with metastatic neuroblastoma (NB) die despite intensive chemotherapy and bone marrow transplantation. The Pediatric Oncology Group conducted a study of paclitaxel, topotecan, and topotecan-cyclophosphamide (topo-cyclo) in newly diagnosed children with stage IV NB.

PATIENTS AND METHODS

There were 102 patients enrolled between September 1993 and October 1995; two of them were later shown to be ineligible. Of the remaining 100 patients, the first cohort of 33 patients received paclitaxel 350 mg/m(2) intravenously (IV) over 24 hours every 14 to 21 days; the next 33 patients received topotecan 2 mg/m(2)/d for 5 days IV every 21 days; a third cohort of 34 patients were treated with IV cyclophosphamide 250 mg/m(2) followed by topotecan 0.75 mg/m(2) each day for 5 days every 21 days. Patients were re-evaluated after two courses and then treated with intensive induction therapy and bone marrow transplantation.

RESULTS

Objective responses (complete response + partial response + mixed response) were documented in 67% of children who received topotecan, 76% after topo-cyclo, and 25% after paclitaxel. Four patients had grade 3 to 4 allergic reactions to paclitaxel; most patients developed grade 3 to 4 marrow suppression after topotecan or topo-cyclo. Neither disease-free survival nor overall survival differed significantly between children who received a phase II agent and those who did not. The 6-year disease-free survival and overall survival rates for all 100 children were 18% +/- 5% and 26% +/- 5%, respectively.

CONCLUSION

Topotecan and topo-cyclo are active in children with NB, are well tolerated, and should be evaluated further in combination regimens.

Results of a phase II upfront window of pharmacokinetically guided topotecan in high-risk medulloblastoma and supratentorial primitive neuroectodermal tumor

PURPOSE

To assess the antitumor efficacy of pharmacokinetically guided topotecan dosing in previously untreated patients with medulloblastoma and supratentorial primitive neuroectodermal tumors, and to evaluate plasma and CSF disposition of topotecan in these patients.

PATIENTS AND METHODS

After maximal surgical resection, 44 children with previously untreated high-risk medulloblastoma were enrolled, of which 36 were assessable for response. The topotecan window consisted of two cycles, administered initially as a 30-minute infusion daily for 5 days, lasting 6 weeks. Pharmacokinetic studies were conducted on day 1 to attain a topotecan lactone area under the plasma concentration-time curve (AUC) of 120 to 160 ng/mL.h. After 10 patients were enrolled, the infusion was modified to 4 hours, with dosage individualization.

RESULTS

Of 36 assessable patients, four patients (11.1%) had a complete response and six (16.6%) showed a partial response, and disease was stable in 17 patients (47.2%). Toxicity was mostly hematologic, with only one patient experiencing treatment delay. The target plasma AUC was achieved in 24 of 32 studies (75%) in the 30-minute infusion group, and in 58 of 93 studies (62%) in the 4-hour infusion group. The desired CSF topotecan exposure was achieved in seven of eight pharmacokinetic studies when the topotecan plasma AUC was within target range.

CONCLUSION

Topotecan is an effective agent against pediatric medulloblastoma in patients who have received no therapy other than surgery. Pharmacokinetically guided dosing achieved the target plasma AUC in the majority of patients. This drug warrants testing as part of standard postradiation chemotherapeutic regimens. Furthermore, these results emphasize the importance of translational research in drug development, which in this case identified an effective drug.

Oral topotecan in children with recurrent or progressive high-grade glioma: a Phase I/II study by the German Society for Pediatric Oncology and Hematology

BACKGROUND

Continuous oral treatment with topotecan may be more effective than the typical 1-day and 5-day treatment schedules. In previous studies of continuous treatment with topotecan, increased intestinal side effects were reported in adult patients; however, the experience in pediatric patients and patients with high-grade glioma is quite limited.

METHODS

Thirty-two pediatric patients with recurrent high-grade glioma (16 females and 16 males; median age, 9.5 years) were enrolled in the current Phase I/II study. Tumor locations included the cerebral cortex (n = 5), pons (n = 18), and other sites (n = 9). An injectable formulation of topotecan was administered orally, in ice-cold orange juice, once daily. The starting dose of 0.4 mg/m(2) per day was escalated on a patient-by-patient basis. At each patient's maximum dose, blood samples were obtained for the determination of plasma hydroxytopotecan and topotecan lactone concentrations and for the calculation of pharmacokinetic quantities.

RESULTS

The toxicity criteria for a maximum tolerated topotecan dose were met in only 19 patients. The primary toxicity type was hematologic. The median maximum tolerated dose was 0.9 mg/m(2) per day (n = 19). The calculated maximum total plasma topotecan concentration was 3.8 ng/mL (n = 7), with an area under the concentration-time curve of 38.4 ng. hours/mL and a half-life of 4.1 hours, which would result in the complete disappearance of topotecan from the plasma after 12 hours. Objective responses were observed in 2 of 13 evaluable patients and lasted for 2.5 and 9 months, respectively (continuous clinical remission, 1 of 14 patients; partial response, 2 of 14 patients; stable disease, 7 of 14 patients; progressive disease, 4 of 14 patients).

CONCLUSIONS

Oral topotecan (median dose, 0.9 mg/m(2) per day) administered once daily was well tolerated and somewhat effective in children with recurrent high-grade glioma. A schedule in which the daily dose is split so that dosing is performed twice daily may be superior to the current schedule.

Second-line chemotherapy with the association of liposomal daunorubicin, carboplatin and etoposide in children with recurrent malignant brain tumors

Progressive or recurrent high-grade gliomas are characterized by a very poor prognosis, and the relevance of second-line chemotherapy is still unassessed. Although it has been reported that liposomal anthracyclines and carboplatin show some activity in these patients, their association has never been investigated. We have treated six children with recurrent high-grade glioma after surgery, radiotherapy and chemotherapy, and one child with progressive teratoid/rhabdoid tumor with the combination of liposomal daunorubicin and carboplatin plus etoposide. Five out of seven children showed a major response and the 29 month progression-free survival was 38%. The above regimen was feasible and children showed only little and transient hematological toxicity. In our opinion, these results justify further investigation of the above combination chemotherapy for recurrent or progressive malignant brain tumors in children.

Childhood ependymoma: a systematic review of treatment options and strategies

Childhood intracranial ependymoma have a dismal prognosis, especially in young children and when a gross total resection cannot be performed. Even in the absence of a radiologically proven residuum, around two-thirds of these young children will have a recurrence. Adjuvant therapy is therefore necessary for most, if not all, patients. Despite some indication that benign ependymoma (WHO grade II) could show a better outcome, histology cannot be used at present to stratify treatment protocols.Craniospinal irradiation combined with posterior fossa boost has deleterious adverse effects on cognition. Consequently, pediatric oncology teams have, firstly, tried to use chemotherapy to delay or avoid irradiation, and secondly, progressively reduced irradiation fields to the tumor bed without altering the prognosis. Cisplatin, at a dose of 120 mg/m(2) (cumulated response rate of 34% [95% CI 19-54%]) is the only single agent that has reproducibly shown some efficacy in ependymoma. Despite some combinations showing efficacy in the adjuvant setting, childhood intracranial ependymomas can, in general, be considered as chemoresistant. The overexpression of the multidrug resistance-1 gene and the 06-methylguanine-DNA methyltransferase have been implicated as possible mechanisms for this phenomenon. As the use of chemotherapy with current agents is questionable, phase II studies with new agents and combinations are necessary. Since the main problem of this disease is local relapse, it may not be necessary to irradiate the whole posterior fossa. However, local control of the disease by irradiation has to be improved. In this respect, hyperfractionation or radiosensitizers may be valuable therapeutic options. The treatment of children with ependymoma is a challenge for all caregivers. There is no doubt that any possible improvement in the management of this rare tumor will only be the result of well designed cooperative trials.

[Topotecan for pediatric patients with resistant and recurrent solid tumors]

BACKGROUND

Topotecan is a cytotoxic drug isolated from the Camptotheca acuminata tree (from China). It is able to block the enzyme DNA topoisomerase I and has recently been used in the treatment of pediatric cancer.

OBJECTIVES

To evaluate our preliminary experience with topotecan in the second line treatment of refractory solid tumors in the pediatric age group. PATIENTS AND MEHTODS: We performed a retrospective study of 10 patients with various recurrent solid tumors resistant to first line treatment who were treated with topotecan alone or in association with other chemotherapeutic agents.

RESULTS

Ten patients with recurrent solid tumors or tumors that were refractory to conventional treatment (two neuroblastomas, three rhabdomyosarcoma, two PNET/Ewing's sarcoma, one anaplastic astrocytoma, one soft tissue sarcoma and one synovial sarcoma) were included. Five patients showed favorable responses (two had complete responses, two had partial responses and one had stable disease). Five patients showed no response. All patients showed grade II-IV hematological toxicity.

CONCLUSIONS

In our experience, topotecan is beneficial in some refractory or recurrent solid tumors, especially neuroblastomas and soft tissue sarcomas. Myelosuppression was tolerable with the use of granulocyte colony-stimulating factors. Patients with a complete response to topotecan could benefit from high-dose chemotherapy and autologous stem cell rescue therapy.

Clinical and cellular pharmacology in relation to solid tumours of childhood

Our understanding of the clinical and cellular pharmacology of drugs commonly used in the treatment of childhood cancer have increased greatly over the past two decades. However, with the exception of childhood acute lymphoblastic leukaemia (ALL), our current knowledge of factors such as inter-patient pharmacokinetic variability and cellular determinants of chemosensitivity has not been utilized in the design of integrated clinical studies. Recent pre-clinical and clinical evaluation of the topoisomerase I inhibitors topotecan and irinotecan has highlighted the potential importance of pharmacological factors in their effectiveness as cytotoxics. In this review, the clinical and cellular pharmacology of vincristine, actinomycin D, doxorubicin, cyclophosphamide, ifosfamide, cisplatin, carboplatin and etoposide will be discussed in relation to the major paediatric solid tumours. For each disease type, knowledge of the clinical and cellular pharmacology of a candidate drug will be related to pharmacodynamic responses such as response, toxicity and prognosis. For diseases such as Wilms' tumour, osteogenic sarcoma and Ewing's tumour, histological response to initial induction chemotherapy is of prognostic significance, and the depth of response is increasingly recognised as an important determinant of prognosis for high-risk neuroblastoma. For several of these tumour types, the dose-intensity of chemotherapy may be an important variable in determining prognosis. However the relationship between pharmacokinetic variability, cellular pharmacology and the major determinants of chemosensitivity to those drugs employed in first line therapy is unknown. The study of these relationships, by means of up front window studies in children who present with high-risk disease, may be as important as the introduction of new agents. Indeed, the optimisation of current therapies may be required to allow a fully informed selection of those children for whom novel therapies are truly needed. Funding and international collaboration at the clinical and scientific level would be required to achieve these aims.

Treatment of paediatric pontine glioma with oral trophosphamide and etoposide

To evaluate the overall survival of paediatric patients with pontine gliomas treated with oral trophosphamide and etoposide. Patients between 3 and 17 years of age with either typical diffuse pontine glioma on MRI or histologically proven anaplastic astrocytoma/glioblastoma multiforme located in the pons, were eligible. Treatment consisted of oral trophosphamide 100 mg x m(-2) x day(-1) combined with oral etoposide at 25 mg x m(-2) x day(-1) starting simultaneously with conventional radiation. Twenty patients were enrolled (median age 6 years, male : female=9 : 11). Surgical procedures included: no surgery: five, open biopsy: three, stereotactic biopsy: six, partial resection: three, and sub-total resection: three. Histological diagnoses included pilocytic astrocytoma: one, astrocytoma with no other specification: three, anaplastic astrocytoma: three, glioblastoma multiforme: eight, no histology: five. The most frequent side effects were haematologic and gastrointestinal. There was no toxic death. The response to combined treatment in 12 evaluable patients was: complete response: 0, partial response: three, stable disease: four, and progressive disease: five. All tumours progressed locally and all patients died. The overall median survival was 8 months. The overall survival rates at 1 and 4 years were: 0.4 and 0.05 respectively. This was not different from a control group of patients documented in the same population. Oral trophosphamide in combination with etoposide did not improve survival of pontine glioma patients. The treatment was well tolerated and should be evaluated for more chemoresponsive paediatric malignancies.

Current management and prognostic factors for adult ependymoma

The optimum therapeutic management in adult ependymoma remains undefined because of the low incidence of this disease and because most of reported series mainly refers to childhood, are retrospective, include a small number of patients and span several decades. The purpose of this article is to analyze, discuss and summarize the current available information regarding the therapeutic approach and the prognostic factors and to provide recommendations for ordinary clinical practice. Some important therapeutic issues like the irradiation dose and volume are also analyzed. Finally, the main open questions as well as current and expected investigation trends are discussed.

Phase II study of topotecan plus cranial radiation for glioblastoma multiforme: results of Radiation Therapy Oncology Group 9513

PURPOSE

A Phase II trial was conducted by the Radiation Therapy Oncology Group (RTOG) to compare the survival of patients with glioblastoma multiforme treated with topotecan combined with standard cranial radiotherapy (RT) for matched patients treated in prior RTOG studies. A secondary objective was to document the acute and late toxicities of this combination of chemotherapy and RT.

METHODS AND MATERIALS

Eighty-seven patients with histologically confirmed glioblastoma multiforme received standard cranial RT (60 Gy/30 fractions in 6 weeks) plus topotecan 1.5 mg/m2 per day i.v. for 5 d/wk every 3 weeks for 3 cycles. Eighty-four patients were evaluated, of whom 60 (71%) were > or =50 years, 44 (52%) were men, and 61 (73%) had a Karnofsky performance status of > or =80. Twenty-nine percent of patients had undergone biopsies, 48% partial resections, and 21% gross total resections. Two resections were unspecified as to the extent of tumor removal. Fourteen percent of patients were recursive partitioning analysis Class III, 46% were Class IV, 35% were Class V, and 5% were Class VI.

RESULTS

The median survival was 9.3 months. Sixty-seven patients (80%) had progression. The 1-year survival rate was 32%. One patient remained alive without recurrence. RTOG 9513 patients were matched with patients in an RTOG clinical trial database from previous clinical trials. The matching variables were age, Karnofsky performance status, mental status, and prior surgery. No statistically significant difference was found between the survival of the study patients and that of the matched patients from the RTOG database. Fifty-four percent of patients had Grade IV acute toxicity. The toxicity was primarily hematologic. Four patients had Grade III late central nervous system toxicities.

CONCLUSION

Topotecan administered at a dose of 1.5 mg/m2 per day i.v. for 5 d/wk every 3 weeks for 3 cycles given concurrently with standard cranial RT for glioblastoma does not produce a statistically significant survival advantage over previously tested therapies. Other methods of administration of topotecan or other camptothecins may provide more effective radiosensitization.

The development of camptothecin analogs in childhood cancers

Camptothecin analogs, agents that target the intranuclear enzyme topoisomerase I, represent a promising new class of anticancer drugs for the treatment of childhood cancer. In preclinical studies, camptothecins, such as topotecan and irinotecan, are highly active against a variety of pediatric malignancies including neuroblastomas, rhabdomyosarcomas, gliomas, and medulloblastomas. In this paper, we review the status of completed and ongoing clinical trials and pharmacokinetic studies of camptothecin analogs in children. These and future planned studies of this novel class of cytotoxic agents are critical to defining the ultimate role of topoisomerase I poisons in the treatment of childhood cancer.

What have we learnt from previous phase II trials to help in the management of childhood brain tumours?

Contrary to major advances in cure rates observed for almost all childhood cancers, progress in reducing brain tumour survival rates remains very limited. Although new drug development in oncology is founded on principles outlined in the organised methodology of phase I, II, and III trials, based on rigorous study design using standardised criteria, this approach has been applied very slowly in the field of neuro-oncology. There are multiple explanations for the paucity of well-conducted prospective clinical trials, such as the rarity and the heterogeneity of these tumours, and the reluctance of some investigators to enroll their patients in constraining trials. Data from the past two decades shows that several methodological problems preclude the drawing of any definite conclusions for the majority of drugs assessed. Among them, the necessity of a central neuropathological and neuroradiological review has been highlighted in, at least, two multicentric studies. Changes in histological diagnosis and grade have been reported in a proportion as high as 20%, and changes in response rate in 14% of the cases. This review of phase II trials for brain tumours reveals a wide array of sometimes arbitrary response definitions, that is if response is defined at all, and most series have enrolled small numbers of patients. We report on the different problems encountered in childhood brain tumours in these phase II trials, and their impact on phase III trials.

Phase I study of topotecan plus cranial radiation for glioblastoma multiforme: results of Radiation Therapy Oncology Group Trial 9507

PURPOSE

A phase I trial was conducted by the Radiation Therapy Oncology Group (RTOG) to determine the maximum-tolerated dose of topotecan that could be safely combined with standard cranial radiation for glioblastoma multiforme. A secondary objective was to document the acute and late toxicities of this combination of chemotherapy and radiation.

PATIENTS AND METHODS

Forty-seven patients with histologically confirmed glioblastoma multiforme were entered onto this phase I trial. Three cycles of topotecan were administered at 21-day intervals commencing at day 1 of cranial radiotherapy (60 Gy/30 fractions). Each cycle consisted of daily 30-minute intravenous (IV) infusions for 5 days. The dose of topotecan was escalated in three-dose increments from 0.5 mg/m(2)/d to 1.0 mg/m(2)/d to 1.5 mg/m(2)/d in different patient groups.

RESULTS

The majority of patients were over age 50. Three dose levels of topotecan were tested. Fifteen patients accrued to level 1 (topotecan dose 0.5 mg/m(2)/d). No grade 4 toxicities were seen. Sixteen patients accrued to level 2 (topotecan dose 1.0 mg/m(2)/d), five of whom had brief episodes of grade 4 neutropenia. Seventeen patients accrued to level 3 (1.5 mg/m(2)/d). Six of these patients had brief episodes of grade 4 neutropenia and four developed grade 3 thrombocytopenia. No serious nonhematologic or late toxicities were seen. Median survival for all patients was 9.7 months. There was no apparent difference in survival by topotecan dose schedule.

CONCLUSION

Toxicity was acceptable at an IV topotecan dose of 1.5 mg/m(2)/d administered daily for 5 days every 21 days for three cycles. A phase II trial has been performed using this dose of topotecan.

Advances in pediatric neuro-oncology

A number of exciting advances have been reported over the past few years in the understanding and treatment of children with brain tumors. The present review highlights many of the publications from this period, focusing on their relevance within the major diagnostic and treatment domains of pediatric oncology (surgery, radiation therapy, chemotherapy, neuropathology, and neuroradiology). Although many of the publications cited provide confirmation of previously reported work, when taken together they form a good framework of the state of the field from the past few years.

Chemotherapy of brain tumors

This is a review of chemotherapy options for patients with brain tumors, both at the time of initial diagnosis and at recurrence. Gliomas, the most common malignant brain tumors, represent the main focus of the review; chemotherapeutic options for supratentorial, brain stem, and optic track gliomas are discussed.