A dose-intensive, cyclophosphamide-based regimen for the treatment of recurrent/progressive or advanced solid tumors of childhood: a report from the Australia and New Zealand Children's Cancer Study Group

Gallium(III) Complex with Cloxyquin Ligands Induces Ferroptosis in Cancer Cells and Is a Potent Agent against Both Differentiated and Tumorigenic Cancer Stem Rhabdomyosarcoma Cells

In this work, gallium(III) complex with cloxyquin (5-chloro-8-quinolinol, HClQ) ligands is shown to effectively inhibit proliferation of rhabdomyosarcoma cells, the frequent, aggressive, and poorly treatable cancer of children. It offers striking selectivity to cancer cells compared to noncancerous human fibroblasts. The data reveal that the complex induces ferroptosis in rhabdomyosarcoma cells, likely due to interfering with iron metabolism. Importantly, it can kill both bulk and stem rhabdomyosarcoma cells. To the best of our knowledge, this is the first compound based on metal other than Fe capable of inducing ferroptosis in cancer cells.

Dipyridophenazine iridium(III) complex as a phototoxic cancer stem cell selective, mitochondria targeting agent

In this work, the mechanism underlying the anticancer activity of a photoactivatable Ir(III) compound of the type [Ir(CˆN)₂(dppz)][PF₆] where CˆN = 1-methyl-2-(2'-thienyl)benzimidazole (complex 1) was investigated. Complex 1 photoactivated by visible light shows potent activity against highly aggressive and poorly treatable Rhabdomyosarcoma (RD) cells, the most frequent soft tissue sarcomas of children. This remarkable activity of 1 was observed not only in RD cells cultured in 2D monolayers but, more importantly, also in 3D spheroids, which resemble in many aspects solid tumors and serve as a promising model to mimic the in vivo situation. Importantly, photoactivated 1 kills not only differentiated RD cells but also even more effectively cancer stem cells (CSCs) of RD. One of the factors responsible for the activity of irradiated 1 in RD CSCs is its ability to produce ROS in these cells more effectively than in differentiated RD cells. Moreover, photoactivated 1 caused in RD differentiated cells and CSCs a significant decrease of mitochondrial membrane potential and promotes opening mitochondrial permeability transition pores in these cells, a mechanism that has never been demonstrated for any other metal-based anticancer complex. The results of this work give evidence that 1 has a potential for further evaluation using in vivo models as a promising chemotherapeutic agent for photodynamic therapy of hardly treatable human Rhabdomyosarcoma, particularly for its activity in both stem and differentiated cancer cells.

Platinum (IV) Derivatives with Cinnamate Axial Ligands as Potent Agents Against Both Differentiated and Tumorigenic Cancer Stem Rhabdomyosarcoma Cells

To design an anticancer drug capable of inhibiting not only the proliferation of the differentiated tumor cells but also reducing the tumorigenic capability of cancer stem cells (CSCs), the new Pt^IV prodrugs with axial cinnamate ligands were synthesized. We demonstrate their superior antiproliferative activity in monolayer and 3D spheroid antiproliferative activity tests using panel of cancer cell lines. An outstanding activity was found against rhabdomyosarcoma cells, one of the most problematic and poorly treatable pediatric tumors. The results also suggest that the released Pt^II compound inhibits antiproliferative activity of cancer cells by DNA-damage mediated mechanism; the released cinnamic acid can trigger processes leading to differentiation, making the CSCs more sensitive to killing by the platinum part of the complex. Pt^IV complex with axial cinnamate ligands is the first Pt^IV prodrug capable of overcoming CSCs resistance and induce death in both CSCs and bulk cancer.

Treatment of children with poor risk solid tumors by further escalation of the VETOPEC regimen including very high-dose cyclophosphamide and peripheral stem cell support: an Australian and New Zealand Children's Hematology and Oncology Group study

BACKGROUND

Children with solid tumors deemed to be poor risk at diagnosis and those who fail to respond or recur after chemotherapy have adverse outcomes. We sought to increase the dosage of cyclophosphamide (CPA) in the VETOPEC regimen (vincristine, etoposide, and CPA) with a view to improving the response rate and survival.

PROCEDURE

Patients underwent peripheral blood stem cell (PBSC) harvest after standard dose VETOPEC (CPA 40 mg/kg/day for 3 days) followed by filgrastim. Those with sufficient PBSC received up to four intensive cycles (ICs) of VETOPEC with CPA dosages of 60-90 mg/kg/day for 3 days (escalated by 5 mg/kg/day in cohorts of at least five patients) followed by PBSC and filgrastim.

RESULTS

Of the 59 enrolled patients, 58 were treated with mobilization chemotherapy and 57 proceeded to PBSC harvest. From 1 to 4 VETOPEC ICs were administered to 51 patients. The maximum tolerated dosage of CPA was not reached. The best response rate during the ICs for patients with recurrent or refractory/progressive disease was 67%; overall survival was 28% at 5 years and 25% at 10 years. The response rate for patients with newly diagnosed high-risk tumors was 89%.

CONCLUSIONS

The VETOPEC regimen with CPA dosages up to 90 mg/kg/day for 3 days followed by PBSC and filgrastim can be given in a timely manner with manageable toxicity. Outcomes were not improved when compared to prior VETOPEC studies. VETOPEC produces high response rates and warrants further evaluation in appropriate patients with newly diagnosed high-risk solid tumors.

Retinoblastoma: A Recent Experience at the National University Hospital, Singapore

Introduction: Retinoblastoma is a very rare disease. There were 30 cases of retinoblastoma diagnosed and treated at National University Hospital (NUH). Materials and Methods: A retrospective chart review was performed on the medical records of 30 patients who were diagnosed with retinoblastoma between 1995 and 2008 at the Department of Paediatrics, National University Hospital, Singapore. Results: The median age at diagnosis was 1.6 years (range, 0-5.9) with a median follow-up of 1.8 years (range, 0.1 to 11.6). The median time from presenting signs to the time of diagnosis was 5.2 months (range, 0-25.2). Common presenting signs of retinoblastoma were identified; the most common of which were leukocoria (50.0%), squinting (13.3%), poor vision (10.0%), strabismus (6.6%) and unknown (33.3%). Of the 30 patients, 10 were from Singapore whilst the other 20 patients were from the surrounding countries. Twelve patients had bilateral disease at the time of diagnosis, while 18 had unilateral disease. Staging information was available in 27 patients. Enucleation was performed in 25 of 30 patients. Radiation therapy was given in 3 patients in 1995 (bilateral disease), 2001 (bilateral disease) and 2003 (unilateral disease). At the time of analysis, 19 patients were alive with no evidence of disease. Overall 5-year survival for the cohort was 88.1% [95% confidence interval (CI), 88.0-100] and event-free survival for the whole cohort was 74.2% (95% CI, 55.8-92.6). Conclusion: In our limited experience, the importance of collaboration and standardisation of the staging system, raising awareness and education of primary healthcare providers and parents are strongly stressed. Key words: Asian experience, Outcome, Staging, Survival

Multiagent chemotherapy studied in a xenograft model of medulloblastoma/primitive neuroectodermal tumour: analysis of the VETOPEC regimen

Brain tumours remain the most important challenge in the treatment of childhood cancer. The intraocular (io) xenograft model was used to study components and variations of the VETOPEC multiagent chemotherapy regimen in the medulloblastoma/primitive neuroectodermal tumour (MB/PNET) xenograft cell line JRMB-6. VETOPEC, a combination of vincristine (VCR), etoposide (VP-16) and escalated dose cyclophosphamide (CPA), has been shown to be highly active in clinical trials. A total of 190 xenografted tumours were treated with one of nine regimens: saline; single agent CPA, VP-16 (single dose [sd], five dosages daily [dx5] or continuous infusion, [ci]) or VCR; combinations of CPA (dx5)+VP-16 (dx5 or ci) or CPA (dx5)+VP-16 (ci)+VCR (sd). Results were calculated using both response (volume reduction >50%) and 'time to progression' (TtP). Effectiveness of CPA was confirmed. Single-agent VCR or VP-16 produced no response. No difference was documented in TtP with VCR, VP-16 (sd) or VP-16 (dx5) versus control, but a significant prolongation occurred when VP-16 was given by ci (p=0.001). With the 3-agent combination of CPA+VP-16 (ci)+VCR a significantly prolonged TtP was documented versus both single agent CPA (p=0.003) and the combination of CPA+VP-16 (dx5) (p=0.004). The results suggest improved efficacy of VP-16 when given as ci in both single-agent and combination settings. The addition of VP-16 (ci)+VCR to an already effective dosage of CPA further prolongs TtP. These data support and progress VETOPEC phase II clinical studies and suggest potential further benefits of prolonged exposure to VP-16 by ci.

Long-term outcomes in children with high-risk neuroblastoma treated with autologous stem cell transplantation

We retrospectively analysed the outcomes of children transplanted for high-risk neuroblastoma (NB) at a single institution predominantly transplanted with total body irradiation and chemotherapy. The aims of this study were to determine the prognostic impact of clinical and biological features and to document long-term health outcomes. Forty patients were transplanted with a single unpurged autograft. Fourteen patients died from disease progression and two from late complications of treatment. Twenty-three patients are alive at a median of 4.6 years from diagnosis. Kaplan-Meier estimates of overall survival at 2, 5 and 10 years are 76+/-7.0, 60.2+/-8.4 and 54.7+/-9.3% following transplant. Response to induction therapy was significantly associated with survival (P<0.01). Long-term complications included growth (100%) and pubertal failure (83%), hearing impairment (73%), orthopaedic complications (63%), renal impairment (47%) and thyroid abnormalities (36%). Intrinsic and acquired resistance to chemotherapy remains the major obstacle to improving outcomes in high-risk NB. Although patients with chemo-sensitive disease are less likely to experience a relapse, substantial therapy-related toxicities result in poor long-term health outcomes for survivors.

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.

Cyclophosphamide Dose Intensification during Induction Therapy for Intermediate-Risk Pediatric Rhabdomyosarcoma Is Feasible but Does Not Improve Outcome

PURPOSE

More than half of pediatric rhabdomyosarcoma cases have intermediate-risk features and suboptimal outcome (3-year failure-free survival estimates, 55 to 76%). Dose intensification of known active agents may improve outcome.

EXPERIMENTAL DESIGN

This pilot study evaluated the feasibility of dose intensification of cyclophosphamide in previously untreated patients ages < 21 years with intermediate-risk rhabdomyosarcoma. Induction therapy comprised four 3-week cycles of VAC: vincristine (V) 1.5 mg/m2 on days 0, 7, and 14; actinomycin D (A) 1.35 mg/m2 on day 0; and dose-intensified cyclophosphamide (C) on days 0, 1, and 2. The three cyclophosphamide dose levels tested were as follows: (a) 1.2 g/m2/dose; (b) 1.5 g/m2/dose; and (c) 1.8 g/m2/dose. Continuation therapy comprised nine additional cycles of VAC with 2.2 g/m2/cycle of C. Radiotherapy was administered at week 0 (parameningeal tumors with intracranial extension) or week 12 or 15 (all others).

RESULTS

Between October 1996 and August 1999, 115 eligible patients were enrolled. Three of 15 patients treated at dose level 2 experienced life-threatening dose-limiting toxicity (typhlitis +/- other severe toxicity). Dose level 1 was the maximum-tolerated dose, and 91 evaluable patients were treated at this level. The 3-year failure-free and overall survival estimates for patients treated at the maximum-tolerated dose were 52% (95% confidence interval, 41-64%) and 67% (95% confidence interval, 56-77%), respectively, at a median follow-up of 3 years.

CONCLUSIONS

A 64% increase in the standard cyclophosphamide dosage during induction (to 3.6 g/m2/cycle) was tolerated. However, outcomes were similar to those observed at lower dosages, suggesting that alkylator dose intensification does not benefit patients with intermediate-risk rhabdomyosarcoma.

Follow-up and management of recurrent Wilms' tumor

Over the past 3 decades, enormous advances have been made in the creation of a standardized treatment protocol for Wilms' tumor. Less morbid regimens for low-risk patients and more efficacious aggressive treatment protocols for high-risk patients have been developed, and continue to be improved with newer studies, such as the NWTS-V. An area that has posed a more challenging aspect of the disease is its relapse. Although a standard follow-up protocol has been produced by in-depth evaluation of previous works, there has been a great deal of difficulty demonstrating improved relapse-free and overall survival rates in re-treatment of children suffering from recurrent Wilms' tumor. Several factors are involved in the success of treatment of relapse, some of which include prerelapse treatment of initial disease and stage, site, and timing of recurrence. New agents and their combination with chemotherapeutics that already have established efficacy are being used for treatment of Wilms' tumor relapse, with varying success. These studies should lead the way for newer investigations in the future. Patients with anaplastic disease, rhabdoid tumors, and clear cell sarcoma are especially in need of these future investigations. Perhaps the true final frontier is establishing the likelihood of patients suffering a relapse. This topic currently is being studied in the fields of biologic markers and gene expression. This knowledge will hopefully, in turn, tailor initial treatment in a more specific manner.

Treatment of refractory osteosarcoma with fractionated cyclophosphamide and etoposide

PURPOSE

Standard multiagent chemotherapy for osteosarcoma may include platinum compounds, doxorubicin, and high-dose methotrexate. By identifying new chemotherapeutic strategies, the outcome of these patients can be improved and the toxicity of treatment regimens decreased.

PATIENTS AND METHODS

The authors evaluated the activity of the combination of cyclophosphamide (500 mg/m2 per day for 5 days) and etoposide (100 mg/m2 per day for 5 days) given with granulocyte colony-stimulating factor (G-CSF) to children with osteosarcoma unresponsive to conventional treatment.

RESULTS

Fourteen patients with refractory osteosarcoma were treated with this combination. Twelve patients had been previously treated with a multiagent regimen that included carboplatin, ifosfamide, methotrexate, and doxorubicin. Seven of 11 evaluable patients had a poor histologic response in their primary tumor at the time of definitive surgery (Huvos grade 1 or 2). Sites of relapse included lung, bone, and brain. A total of 47 courses were given. An overall response rate of 28.5% was achieved. A complete response was obtained in one patient (7.1%), a partial response was obtained in three patients (21.4%), and stable disease for 1 to 4 months was achieved in five patients (35.7%). Five patients (35.7%) had progressive disease. Grade 4 neutropenia was the primary form of toxicity observed; the median duration of absolute neurophil count less than 500/microL was 4 days.

CONCLUSIONS

The combination of cyclophosphamide and etoposide resulted in a response rate of 28.5% in patients with refractory or relapsed osteosarcoma, and its incorporation into front-line therapies deserves further evaluation.

Medulloblastoma/primitive neuroectodermal tumour studied as a Matrigel enhanced subcutaneous xenograft model

An important role for pre-clinical models of medulloblastoma/primitive neuroectodermal tumour (MB/PNET) is inhibited by the limitations of conventional heterotransplantation. Nine cohorts of MB/PNET were studied for subcutaneous engraftment in nude mice by both conventional and Matrigel supplemented methods. While no subcutaneous tumours resulted from 63 conventional attempts, an aggregate 41 xenografts from 72 injections (57%) were produced when Matrigel was added to the cell suspension. In subsequent passage, engraftment rate approached 100%. To study the response to chemotherapeutic agents in the model, a total of 221 tumours in 3 cohorts were treated using one of the following: cisplatin, carboplatin, vincristine, cyclophosphamide, diaziquone, or saline control. While all agents demonstrated statistically significant activity, cyclophosphamide proved to be particularly effective. The potential applications of this xenograft model in the biologic as well as therapeutic study of MB/PNET deserve continuing investigation.

How effective is dose-intensive/myeloablative therapy against Ewing's sarcoma/primitive neuroectodermal tumor metastatic to bone or bone marrow? The Memorial Sloan-Kettering experience and a literature review

PURPOSE

Attempts to improve outcomes of patients with Ewing's sarcoma/primitive neuroectodermal tumor (ES/PNET) metastatic to bone/bone marrow (BM) have focused on chemotherapy dose intensification strategies. We now present results achieved with that approach, as carried out at Memorial Sloan-Kettering Cancer Center (MSKCC) and as reported in the literature.

PATIENTS AND METHODS

Twenty-one unselected MSKCC patients with newly diagnosed ES/PNET metastatic to bone/BM received the "P6" protocol which includes cycles of cyclophosphamide (4.2 g/m(2))/doxorubicin (75 mg/m(2))/vincristine and cycles of ifosfamide (9 g/m(2))/etoposide (500 mg/m(2)). Patients in complete/very good partial remission (CR/VGPR) after P6 received myeloablative therapy with either total-body irradiation (TBI) (hyperfractionated 15 Gy)/melphalan (180 mg/m(2)) or thiotepa (900 mg/m(2))/carboplatin (1,500 mg/m(2)). We reviewed the literature.

RESULTS

Only one MSKCC patient became a long-term event-free survivor; all but one relapse was in a distant site. Initial responses to P6 were CR/VGPR in 19 patients, but eight of them plus two others developed PD while receiving or shortly after completing P6. Eight patients were treated with TBI/melphalan: four relapsed 2 to 7 months after transplantation; two died early of toxicity; one died of pulmonary failure 17 months after transplantation (no evidence of ES/PNET); and one remains in CR at more than 7 years. The three patients treated with thiotepa/carboplatin relapsed 3 to 4 months after transplantation. All reports on large series of unselected patients with ES/PNET metastatic to bone/BM showed similarly unsatisfactory results. Poor outcome was seen with use of active agents for ES/PNET-cyclophosphamide, ifosfamide, doxorubicin, dactinomycin, vincristine, etoposide - at standard dosages for prolonged periods of time and at higher dosages in intensive regimens for short or prolonged periods of time. No improvements in event-free survival rates occurred with successive cooperative group or large single-institutional studies that used increasingly aggressive chemotherapeutic approaches. Inclusion of ifosfamide with or without etoposide made no difference nor did consolidation of remission with myeloablative chemoradiotherapy. Secondary leukemia emerged as a major risk with dose-intensive regimens.

CONCLUSION

The MSKCC experience and findings reported in the literature suggest that dose-intensive use of the chemotherapy agents with established activity against ES/PNET is reaching its efficacy and toxicity limits. A major impact on prognosis awaits the development of entirely novel therapies.

Pilot study of topotecan and high-dose cyclophosphamide for resistant pediatric solid tumors

BACKGROUND

The recommended dosages of topotecan and cyclophosphamide in combination for prior-treated patients-3.75 mg/m(2) and 1,250 mg/m(2) in children, 5 mg/m(2) and 600 mg/m(2) in adults, respectively-are well below those of each agent when used singly. We tested the hypothesis that much higher dosing would meet critical goals of salvage therapy: antitumor effect and a lack of toxicity to key organs, so as not to preclude subsequent consolidative treatments needed for cure.

PROCEDURE

Patients with resistant pediatric solid tumors received cyclophosphamide 4,200 mg/m(2) by 48 hr infusion, and topotecan 6 mg/m(2) by 72 hr infusion (HD-Cy/Topo). Mesna and granulocyte colony-stimulating factor were used. Cycles were repeated when neutrophil counts were >1,000/uL and platelet counts were >75,000/uL.

RESULTS

Twenty-eight patients, aged 2 to 33 years (median, 14), received one (n = 4), two (n = 15), or > or =3 (n = 9) cycles of HD-Cy/Topo. All patients had previously received > or =6 cycles of other therapy, high-dose alkylator-based chemotherapy, and/or etoposide- and doxorubicin-containing regimens. HD-Cy/Topo was given in an outpatient setting. Profound myelosuppression was the major toxicity, but retreatment was possible by day 28, and preliminary results with peripheral blood stem cell collections showed a sparing effect on hemopoietic stem cells. Mucositis was uncommon. After HD-Cy/Topo, cardiac, renal, hepatic, and pulmonary function remained within the normal range. Partial or minor responses were noted in neuroblastoma, desmoplastic small round-cell tumor, Ewing sarcoma, rhabdomyosarcoma, and osteosarcoma.

CONCLUSIONS

Its antitumor potential and limited toxicity make HD-Cy/Topo an attractive choice for inclusion in aggressive salvage programs aimed at achieving cures of resistant tumors. It may also merit incorporation into frontline treatment protocols.

Fractionated cyclophosphamide and etoposide for children with advanced or refractory solid tumors: a phase II window study

PURPOSE

Cyclophosphamide (CPA) has a broad spectrum of activity against solid tumors. Hepatic self-induction of the active metabolite 4-hydroxycyclophosphamide occurs after repeated administration. We evaluated the clinical efficacy of a window regimen that administers fractionated CPA in conjunction with etoposide (VP16) in children with advanced or refractory solid tumors.

PATIENTS AND METHODS

Seventeen children with advanced (n = 12) or refractory (n = 5) solid tumors were entered onto this phase II window study. The treatment regimen consisted of intravenous (IV) CPA 500 mg/m(2)/d and IV VP16 100 mg/m(2)/d. Both drugs were administered daily by short infusions for 5 consecutive days.

RESULTS

A total of 34 courses were administered, with a median of two courses per patient. The median interval between chemotherapy courses was 21 days (range, 17 to 35 days). Thirty-three courses were assessable for toxicity, and all patients were assessable for response. No life-threatening toxicities were observed. The incidence of grade 3 or 4 neutropenia was 94% and of fever and neutropenia 38%. Fever and neutropenia occurred after 12 of 26 courses without recombinant human granulocyte colony-stimulating factor (rhG-CSF) and after one of eight courses with rhG-CSF (P =. 09). Grade 3 or 4 thrombocytopenia occurred after 10 courses (29%). There were no positive blood cultures. One heavily pretreated patient developed a localized perirectal abscess that required drainage. There were 10 patients (59%) with partial responses, four (23.5%) with stable disease, and three with progressive disease.

CONCLUSION

Fractionated IV CPA and VP16 over 5 days can be safely administered in children with advanced or refractory solid tumors and has notable antineoplastic activity.

A phase I dose escalation of combination chemotherapy with granulocyte-macrophage-colony stimulating factor in patients with neuroblastoma

BACKGROUND

Dose intensity is important in the response to chemotherapy in patients with advanced neuroblastoma. The aim of the current study was to determine the maximum tolerated dose of a combination chemotherapy regimen in the treatment of patients with recurrent neuroblastoma and peripheral neuroepithelioma (primitive neuroectodermal tumor [PNET]) and whether the use of growth factor would allow increased dose intensity.

METHODS

Twenty-nine patients diagnosed with recurrent neuroblastoma or PNET were treated with a combination chemotherapy regimen of cisplatin, 160 mg/m(2)/96 hours; doxorubicin, 40 mg/m(2)/96 hours; and escalated doses of etoposide and ifosfamide. Granulocyte-macrophage-colony stimulating factor (GM-CSF) was administered beginning 24 hours after the completion of the chemotherapy. Courses were repeated at 28-day intervals. Once the maximum tolerated dose (MTD) was defined the interval between courses was shortened by administering the next course as soon as the patient's neutrophil and platelet counts had recovered to > 1500/microL and > 75,000/microL, respectively.

RESULTS

Sixteen patients were treated at 3 dose levels. The MTD was defined as 10 g/m(2)/96 hours of ifosfamide and 800 mg/m(2)/96 hours of etoposide. Thirteen additional patients then were treated at 1 level below the MTD to try and decrease the interval between courses. A total of 12 of 29 patients developed a dose-limiting toxicity (DLT) after the first course of therapy. The most common DLT was gastrointestinal toxicity followed by hematologic toxicity. Twenty-seven patients developed standard National Cancer Institute criteria Grade 3 or 4 toxicity after the first course of treatment and 7 patients achieved a complete or partial response to the first course. The use of GM-CSF did not allow further dose intensification.

CONCLUSIONS

This chemotherapy combination achieved a 31% overall response rate. A further increase in the dose intensity of this regimen may require supportive measures other than GM-CSF to decrease toxicity.

Clinical presentation, diagnosis, and pharmacotherapy of patients with primary brain tumors

OBJECTIVE

To briefly review the clinical presentation and diagnosis of patients with primary brain tumors, followed by an in-depth survey of the pertinent pharmacotherapy.

DATA SOURCES

A detailed search of the neurologic, neurosurgical, and oncologic literature for basic science research, clinical studies, and review articles related to chemotherapy and pharmacotherapy of primary brain tumors.

STUDY SELECTION

Relevant studies on tissue culture systems, animals, and humans examining the mechanisms of action, pharmacokinetics, clinical pharmacology, and treatment results of chemotherapeutic agents for primary brain tumors. In addition, studies of pharmacologic agents administered for supportive care and symptom control are reviewed.

DATA SYNTHESIS

Primary brain tumors derive from cells within the intracranial cavity and generally present with headache, seizure activity, cognitive changes, and weakness. They are diagnosed most efficiently with magnetic resonance imaging. After diagnosis, the most common supportive medications include corticosteroids, gastric acid inhibitors, and anticonvulsants. Chemotherapy is adjunctive treatment for patients with malignant tumors and selected recurrent or progressive benign neoplasms. In general, the most effective chemotherapeutic drugs are alkylating agents such as the nitrosoureas, procarbazine, cisplatin, and carboplatin. Other agents used include cyclophosphamide, methotrexate, vincristine, and etoposide. Angiogenesis inhibitors and gene therapy comprise some of the novel therapeutic strategies under investigation.

CONCLUSIONS

The efficacy of chemotherapy for primary brain tumors remains modest. Novel agents must be discovered that are more specific and attack tumor cells at the molecular level of tumorigenesis. Furthermore, strategies must be developed to counteract the pervasive problem of brain tumor chemoresistance.

Postoperative chemotherapy in children less than 4 years of age with malignant brain tumors: promising initial response to a VETOPEC-based regimen. A Study of the Australian and New Zealand Children's Cancer Study Group (ANZCCSG)

PURPOSE

Postoperative chemotherapy with indefinite postponement of radiation therapy in children < 4 years old with brain tumors was investigated in a multi-institutional study.

PATIENTS AND METHODS

From 1991 to 1995, 42 patients aged 3 to 47 months (median 20) with brain tumors were enrolled in a 2-phase chemotherapy protocol: 16 patients had medulloblastoma (MB); 8 had supratentorial primitive neuroectodermal tumor (PNET); 14 had ependymoma; and 4 had other tumors. The initial phase was comprised of 4 courses of the 3-drug regimen: vincristine (VCR), etoposide (VP-16), and intensive cyclophosphamide (CPA) in a previously reported schedule (VETOPEC). The continuation phase was comprised of 2-drug courses: A, CPA + VCR; B, cisplatin + VP-16; and C, carboplatin + VP-16, for a total duration of 64 weeks.

RESULTS

Response to VETOPEC was evaluable in 28 patients with postresection residual (25) and/or metastatic (1 M2, 6 M3) tumor. There were 9 complete responses (CR) and 9 partial responses (PR) with a combined CR + PR of 64% (95% confidence interval [CI] 44 to 81). In 12 evaluable patients with MB, CR + PR was 82% (48 to 98); in 6 patients with PNET, 50% (12 to 88); and, in 8 patients with ependymoma, 86% (42 to 99). Of 40 patients eligible for further analysis, 6 remain progression-free at a median of 30 months, 14 are alive at a median of 38 months, 29 have progressed at a median of 7 months (range, 2 to 37 months), and 26 have died. The progression-free and overall survival rates at 36 months are estimated to be 11% (95% CI 1 to 22) and 34% (18 to 50), respectively.

CONCLUSIONS

The initial response to the VETOPEC regimen is encouraging and warrants study of further dose escalation. Survival remains poor with current strategies in this high-risk population.