A phase II study of diaziquone in children with recurrent or progressive primary brain tumors: a report from the Childrens Cancer Study Group

Medulloblastoma in childhood: revisiting intrathecal therapy in infants and children

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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.

Intraventricular gliomas

Gliomas are the most common primary brain tumor in adults, and those within or relating to the ventricular surface represent a less common but important subcategory. The most common intraventricular gliomas include ependymomas, SEs, and SEGAs. Other less common varieties have been reported, including chordoid gliomas, glioblastoma multiforme, and mixed glial-neuronal tumors. Each type of intraventricular glioma is associated with its own unique constellation of epidemiologic, clinical, radiologic, and pathologic defining characteristics. Each tumor type has its own management considerations and nuances with unique prognostic indicators and outcomes. The outcome for certain intraventricular gliomas (especially ependymomas) remains relatively poor. Future advancements in surgical technique are likely to have only a modest impact on improvement of outcome. Translational research aiming to advance the knowledge of tumor biology into new targeted cellular and molecular therapies holds tremendous promise to improve the overall outcome. Additionally, more thorough delineation of prognostic factors as well as modifications and refinements to radiation and chemotherapy may help to improve the still significantly poor outcomes for patients harboring these lesions. Future cooperative intra- and interinstitutional efforts between scientists and clinicians will hopefully culminate in an improved outlook and eventual cure for patients with gliomas.

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.

Pharmacotherapy of malignant astrocytomas of children and adults: current strategies and future trends

This article reviews the conceptual progression in the pharmacological therapy of malignant astrocytoma (MA) over the past decade, and its future trends. It is a selective rather than an exhaustive inventory of literature citations. The experience of the Brain Tumour Cooperative Group (BTCG) and earlier phase III trials are summarised to place subsequent phase II and I studies of single and combination agent chemotherapy in perspective. The BTCG experience of the 1970s to 1980s may be summarised to indicate that external beam radiotherapy (EBRT) is therapeutic, although not curative, and not further improved upon by altering fractionation schedules, or the addition of radioenhancers. Whole brain and reduced whole brain EBRT with focal boost were comparable regimens. Nitrosourea-based, adjuvant chemotherapy provided a modest improvement in survival among adult patients, which was comparable with that of other single drugs or multidrug regimes. The multiagent schedules, however, had a correspondingly higher toxicity rate. Intra-arterial administration was associated with significant risk, which conferred no therapeutic advantage. The trend of the past decade has been towards multiagent chemotherapy although its benefit cannot be predicted from the classic prognostic factors. Published experience with investigational trials utilising myeloablative chemotherapy with autologous bone marrow or peripheral blood stem cell haemopoietic support, drug delivery enhancement methods and radiosensitisers is critically reviewed. None of these approaches have achieved wide-spread acceptance in the treatment of adult patients with MA. Greater attention is placed on recent 'chemoradiotherapy' trials, which attempt to integrate and maximise the cytoreductive potential of both modalities. This approach holds promise as an effective means to delay or overcome the evolution of tumour resistance, which is probably one of the dominant determinants of prognosis. However, the efficacy of this approach remains unproven. New chemotherapeutic agents as well as biological response modifiers, protein kinase inhibitors, angiogenesis inhibitors and gene therapy are also discussed; their role in the therapeutic armamentarium has not been defined.

Chemotherapy for advanced CNS ependymoma

BACKGROUND

The role of chemotherapy in recurrent ependymoma is poorly defined. This study was performed to help clarify the benefits of chemotherapy in this setting.

PATIENTS AND METHODS

We retrospectively reviewed the charts of patients with advanced ependymoma of the CNS who received chemotherapy in our institution between 1974 and 1993, inclusive. Sixteen consecutive patients were treated with regimens containing either nitrosourea, platinum, or other combinations exclusive of nitrosourea or platinum. No patient received nitrosourea and platinum concurrently. Two methods were used to define response. The first was a direct comparison of radiographic images before and after chemotherapy more than one month apart. A second broader definition of response that employed four other criteria in addition to imaging studies (symptoms, signs, performance status, and neurologic functional status) was also used.

RESULTS

Results were as follows (response rate by imaging studies followed by response rate by scoring in parenthesis): Platinum-based chemotherapy resulted in a 67% (83%) response rate with 33% (0%) remaining stable. Nitrosourea-based regimens resulted in a 25% (60%) response rate with 50% (10%) remaining stable. When combinations other than platinum or nitrosourea were used, 11% (22%) responded and 56% (44%) remained stable. Relative differences in response rates between chemotherapy regimens persisted when the data were analyzed by grade. Median time to progression was 6, 10, and 3 months, respectively.

CONCLUSION

Platinum-based chemotherapy regimens appear to result in higher response rates with lower rates of progression than nitrosourea-based regimens. Other regimens that do not include cisplatinum or nitrosourea appear to be even less effective.

Response of brain tumors to chemotherapy, evaluated in a clinically relevant xenograft model

Chemotherapy for brain tumors remains unsatisfactory. Despite increasing participation in clinical trials, there is a clear need for pre-clinical models. Heterotransplantation of surgical specimens directly into the anterior chamber of the nude mouse eye has been demonstrated to produce evaluable xenografts. Drug access in this model is considered to mimic the blood-brain barrier. Five clinical specimens in 3 children with primitive neuroectodermal tumor/medulloblastoma were the sources of 293 intraocular xenografts (5 cohorts by source). Each tumor-bearing mouse received 1 of 5 drugs or normal saline, by intraperitoneal injection, weekly for 5 weeks. Response was monitored for up to 22 weeks, using a staging system which estimates the proportion of the anterior chamber filled by tumor. Results were analysed both as response rates (shrinkage in excess of 50%) at the conclusion of the treatment course and as time to tumor progression by the life table method. Comparison of response rates within cohorts by source of xenografts (exact chi-square test for overall and 2-sided Fisher's exact test for paired comparisons) indicated cyclophosphamide to be the most effective single agent. In logrank analyses cyclophosphamide achieved significantly longer delays to progression than all other drugs in one cohort and longer delays than all but diaziquone in 2 other cohorts. The intraocular xenograft model is a clinically relevant system for the study of therapeutic agents in brain tumors. The effectiveness of intensive dosage cyclophosphamide in a model dependent on access across the blood-aqueous barrier is important and consistent with recent clinical data.

Superiority of PCNU over AZQ in the treatment of primary brain tumors: results of a prospective randomized trial (81-20) by the Brain Tumor Study Group

PURPOSE

A two-arm randomized clinical trial was performed to determine the efficacy of PCNU and AZQ in the treatment of de novo or recurrent primary brain tumors. An additional objective was to gather information on the administration and toxicity of these compounds, supplementing that obtained previously in phase I/II studies.

METHODS

During 1982 and 1983 the Brain Tumor Study Group randomized 152 adult patients with primary brain tumors to receive PCNU 75-100 mg/m2 intravenously (IV) every 8 weeks or AZQ 15 mg/m2 IV once a week for 4 weeks, every 6-8 weeks. All patients who had not received 'full dose' radiotherapy before randomization received it concurrently with the first course of protocol chemotherapy. The data were analyzed for the total randomized population (RP), and for 130 patients in the valid study group (VSG) formed by excluding 22 patients for whom the histologic diagnosis was not documented by central review.

RESULTS

Median survival times were 11.0 months for the PCNU group and 8.4 months for the AZQ group. The difference in survival curves was statistically significant for the RP (p = 0.01) and the VSG (p = 0.02). Life-table analysis of the VSG showed estimated 2-year survivals of 34% for PCNU and 11% for AZQ. The advantage of PCNU remained significant (p = 0.006) after adjustment for histopathologic category, age, initial performance status, and interval from initial reported surgery. Myelosuppression was the principal toxicity in both groups.

Combination of aziridinylbenzoquinone and cis-platinum with radiation therapy in the 9L rat brain tumor model

PURPOSE

We evaluated the potentiating effects of aziridinylbenzoquinone (AZQ) and cis-platinum on the prolongation of survival by radiation therapy in a rat brain tumor model.

METHODS AND MATERIALS

On day 10 following intracranial inoculation of the 9L gliosarcoma, Fischer 344 rats were treated with radiation therapy (Cesium-137 source irradiator) and/or chemotherapy delivered either systemically (intraperitoneal or intravenous), or intracranially directly into the tumor in a volume of 5 microliters. Increased life spans were calculated relative to the median survival time for the control (ILS-C) or to the median survival time for radiation therapy only (ILS-RT) group.

RESULTS

Median survival time for untreated rats was 22 +/- 3 days for seven experiments. Radiation therapy (16 Gy) produced a significant (p < 0.002) improvement in survival, with an average ILS-C of 75 +/- 19%. Systemic AZQ (1 or 5 intravenous injections of 0.5 mg/kg) produced ILS's of 0 and 23%, the latter being significant (p = 0.002). When added to radiation therapy, there were further improvements (ILS-RT's of 47 and 72%), but these were not significant. Intratumor AZQ (40 or 50 micrograms intracranially) produced significant ILS-C's of 30 and 33% (p = 0.01 and 0.0002, respectively). Added to radiation therapy, intracranial AZQ produced improvements (ILS-RT's of 5 and 102%), with only the latter being significantly improved (p = 0.009). Cis-platinum (3 micrograms intracranially) produced ILS-C's of 13 and 6%, neither significantly different from controls. Added to radiation therapy, cisplatinum caused improvements (ILS-RT's of 18 and 64%), with only the latter significant (p = 0.049).

CONCLUSION

These results demonstrate that AZQ delivered systemically, and AZQ and cis-platinum delivered intracranially, can produce statistically significant improvements in the survival of rats burdened with the 9L brain tumor. The agents delivered intracranially significantly potentiated the prolongation of survival obtained by radiation therapy. This preclinical evidence suggests that combining radiation therapy with these cytotoxic chemotherapeutic agents may benefit patients with high-grade malignant brain tumors.