Phase II study of neoadjuvant 1, 3-bis (2-chloroethyl)-1-nitrosourea and temozolomide for newly diagnosed anaplastic glioma

Using a pre-radiation window to identify potentially active cytotoxic agents in adults with newly diagnosed glioblastoma

Therapies shown to improve outcomes in patients with recurrent cancers are commonly used in the neoadjuvant setting to optimize surgery, reduce radiation fields, and treat micrometastatic disease. While the use of pre-radiation chemotherapy (PRC) has flourished in systemic cancers, it has not seen the same level of use in glioblastomas. This review documents these trajectories and highlights the potential of PRC to rapidly and safely screen cytotoxic drugs for efficacy in patients with newly diagnosed glioblastoma. Prospective trials of adults with newly diagnosed systemic and brain cancers treated with PRC published between 1980 and 2023 were identified in PubMed. The National Comprehensive Cancer Network guidelines were used to document the standard use of PRC in patients with systemic and brain cancers. Over 5000 prospective PRC trials in solid tumors were identified. These accrued  >1 million patients and resulted in neoadjuvant therapies being the standard of care in ~28 systemic cancers. Only 50 similar trials (2206 patients) were identified in high-grade gliomas. In 13 trials containing PRC temozolomide (n = 846), radiographic responses ranged from 6 to 53% with a median survival of ~13 months. Glioblastoma PRC trials were not associated with unexpected toxicities or major negative impacts on survival. Pre-radiation chemotherapy in patients with glioblastoma appears safe and feasible. The pre-radiation window is ideally suited to rapidly screen cytotoxic agents for efficacy. It permits radiographic response as a primary outcome, small sample sizes, and initiation of standard therapies a few months after diagnosis. Pre-radiation chemotherapy may be most appropriate for patients with glioblastoma who are unlikely to benefit from temozolomide.

Neoadjuvant clinical trials in adults with newly diagnosed high-grade glioma: A systematic review

BACKGROUND

High-grade gliomas are devastating cancers that remain incurable with standard surgical resection and radiochemotherapy. Although beneficial against neoplasms, radiation lowers lymphocyte counts, weakens immune activation, and recruits suppressive myeloid cells impairing immune responses. Tumor environments treated with radiation experience long-term immunosuppression, reducing immunotherapy effectiveness and contributing to recurrence. Investigating pre-radiation treatments in newly diagnosed patients could identify active agents, assess immunotherapy impact, and enable multiomic analyses without radiation-induced confounding factors. This literature review was conducted to describe the feasibility, safety, and outcomes of postsurgical, pre-radiation clinical trials for adults with newly diagnosed high-grade glioma.

METHODS

A systematic review was performed of the English-language literature reporting results of clinical trials for adults with newly diagnosed high-grade glioma administered postsurgical treatment prior to radiation therapy. A search was conducted in PubMed and references cited in research and review articles were also considered.

RESULTS

From 1991 to 2024, 52 clinical trials were identified: 3 phase I, 38 phase II, 4 phase III, and 7 of unknown phase. Nine trials were randomized, 24 were multicenter trials, 21 investigated temozolomide-containing regimens, and 12 focused on inoperable tumors, involving a total of 2737 patients.

CONCLUSION

Pre-radiation neoadjuvant studies are feasible and may identify active drugs. This is particularly relevant in the era of personalized medicine with brain-penetrant drugs, targeted therapy, and immuno-oncology advancements. Investigating pre-radiation treatments in newly diagnosed high-grade glioma is a viable approach to rapidly identify active and inactive regimens while the immune system and tumor microenvironment remain intact.

Surgical management of Glioma Grade 4: technical update from the neuro-oncology section of the Italian Society of Neurosurgery (SINch®): a systematic review

PURPOSE

The extent of resection (EOR) is an independent prognostic factor for overall survival (OS) in adult patients with Glioma Grade 4 (GG4). The aim of the neuro-oncology section of the Italian Society of Neurosurgery (SINch®) was to provide a general overview of the current trends and technical tools to reach this goal.

METHODS

A systematic review was performed. The results were divided and ordered, by an expert team of surgeons, to assess the Class of Evidence (CE) and Strength of Recommendation (SR) of perioperative drugs management, imaging, surgery, intraoperative imaging, estimation of EOR, surgery at tumor progression and surgery in elderly patients.

RESULTS

A total of 352 studies were identified, including 299 retrospective studies and 53 reviews/meta-analysis. The use of Dexamethasone and the avoidance of prophylaxis with anti-seizure medications reached a CE I and SR A. A preoperative imaging standard protocol was defined with CE II and SR B and usefulness of an early postoperative MRI, with CE II and SR B. The EOR was defined the strongest independent risk factor for both OS and tumor recurrence with CE II and SR B. For intraoperative imaging only the use of 5-ALA reached a CE II and SR B. The estimation of EOR was established to be fundamental in planning postoperative adjuvant treatments with CE II and SR B and the stereotactic image-guided brain biopsy to be the procedure of choice when an extensive surgical resection is not feasible (CE II and SR B).

CONCLUSIONS

A growing number of evidences evidence support the role of maximal safe resection as primary OS predictor in GG4 patients. The ongoing development of intraoperative techniques for a precise real-time identification of peritumoral functional pathways enables surgeons to maximize EOR minimizing the post-operative morbidity.

Harmine Augments the Cytotoxic and Anti-invasive Potential of Temozolomide Against Glioblastoma Multiforme Cells

Background: Glioblastoma multiforme (GBM) is considered the deadliest human cancer. Temozolomide is now a part of postresection standard chemotherapy for this type of cancer. Unfortunately, resistance to temozolomide is a major obstacle to treatment success. Combination therapy with natural anticancer agents increases the activity of temozolomide against cancer cells. Objectives: This study aimed to assess the effects of temozolomide in combination with harmine against GBM cells. Methods: Cancer cells were treated with temozolomide and/or harmine. After 24, 48, 72, and 96 h, the viability of the cells was assessed by the MTT test. The combination index and dose reduction index were determined by CompuSyn software. Tumor invasion potential was investigated by evaluating cell migration, invasion, and adhesion. The real-time PCR technique was done to study the expression pattern of two genes involved in cancer cell invasion. Statistical analysis was performed using one-way analysis of variance and Tukey’s post-hoc test, and differences were considered non-significant at P > 0.05. Results: After treatment with temozolomide, cell viability showed a concentration- and time-dependent decrease, and the cells’ survival rate decreased. The combination of temozolomide and harmine had a synergistic effect. Also, temozolomide and/or harmine treatment decreased cancer cells’ migration, invasion, and adhesion potentials, as well as the expression of metalloproteinases 2 and 9 in T98G cells. Conclusions: The combination of temozolomide and harmine can be promising for the successful treatment of GBM.

TEMOBIC: Phase II Trial of Neoadjuvant Chemotherapy for Unresectable Anaplastic Gliomas: An ANOCEF Study

LESSONS LEARNED

Treatment with temozolomide and BCNU was associated with substantial response and survival rates for patients with unresectable anaplastic glioma, suggesting potential therapeutic alternative for these patients. The optimal treatment for unresectable large anaplastic gliomas remains debated.

BACKGROUND

The optimal treatment for unresectable large anaplastic gliomas remains debated.

METHODS

Adult patients with histologically proven unresectable anaplastic oligodendroglioma or mixed gliomas (World Health Organization [WHO] 2007) were eligible. Treatment consisted of BCNU (150 mg/m² ) and temozolomide (110 mg/m² for 5 days) every 6 weeks for six cycles before radiotherapy.

RESULTS

Between December 2005 and December 2009, 55 patients (median age of 53.1 years; range, 20.5-70.2) were included. Forty percent of patients presented with wild-type IDH1 gliomas, and 30% presented with methylated MGMT promoter. Median progression-free survival (PFS), centralized PFS, and overall survival (OS) were 16.6 (95% confidence interval [CI], 12.8-20.3), 15.4 (95% CI, 10.0-20.8), and 25.4 (95% CI, 17.5-33.2) months, respectively. Complete and partial responses under chemotherapy were observed for 28.3% and 17% of patients, respectively. Radiotherapy completion was achieved for 75% of patients. Preservation of functional status and self-care capability (Karnofsky performance status [KPS] ≥70) were preserved until disease progression for 69% of patients. Grade ≥ 3 toxicities were reported for 52% of patients, and three deaths were related to treatment. By multivariate analyses including age and KPS, IDH mutation was associated with better prognostic for both PFS and OS, whereas MGMT promoter methylation was associated with better OS.

CONCLUSION

The association of BCNU and temozolomide upfront is active for patients with unresectable anaplastic gliomas, but toxicity limits its use.

Inhibitors of GLUT/SLC2A Enhance the Action of BCNU and Temozolomide against High-Grade Gliomas

Glucose transport across glioblastoma membranes plays a crucial role in maintaining the enhanced glycolysis typical of high-grade gliomas and glioblastoma. We tested the ability of two inhibitors of the glucose transporters GLUT/SLC2A superfamily, indinavir (IDV) and ritonavir (RTV), and of one inhibitor of the Na/glucose antiporter type 2 (SGLT2/SLC5A2) superfamily, phlorizin (PHZ), in decreasing glucose consumption and cell proliferation of human and murine glioblastoma cells. We found in vitro that RTV, active on at least three different GLUT/SLC2A transporters, was more effective than IDV, a specific inhibitor of GLUT4/SLC2A4, both in decreasing glucose consumption and lactate production and in inhibiting growth of U87MG and Hu197 human glioblastoma cell lines and primary cultures of human glioblastoma. PHZ was inactive on the same cells. Similar results were obtained when cells were grown in adherence or as 3D multicellular tumor spheroids. RTV treatment but not IDV treatment induced AMP-activated protein kinase (AMPKα) phosphorylation that paralleled the decrease in glycolytic activity and cell growth. IDV, but not RTV, induced an increase in GLUT1/SLC2A1 whose activity could compensate for the inhibition of GLUT4/SLC2A4 by IDV. RTV and IDV pass poorly the blood brain barrier and are unlikely to reach sufficient liquoral concentrations in vivo to inhibit glioblastoma growth as single agents. Isobologram analysis of the association of RTV or IDV and 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) or 4-methyl-5-oxo-2,3,4,6,8-pentazabicyclo[4.3.0]nona-2,7,9-triene-9-carboxamide (TMZ) indicated synergy only with RTV on inhibition of glioblastoma cells. Finally, we tested in vivo the combination of RTV and BCNU on established GL261 tumors. This drug combination increased the overall survival and allowed a five-fold reduction in the dose of BCNU.

Phase I/II Study of Temozolomide Plus Nimustine Chemotherapy for Recurrent Malignant Gliomas: Kyoto Neuro-oncology Group

The objective of this phase I/II study was to examine the efficacy and toxicity profile of temozolomide (TMZ) plus nimustine (ACNU). Patients who had received a standard radiotherapy with one or two previous chemo-regimens were enrolled. In phase I, the maximum-tolerated dose (MTD) by TMZ (150 mg/m2/day) (Day 1-5) plus various doses of ACNU (30, 35, 40, 45 mg/m2/day) (Day 15) per 4 weeks was defined on a standard 3 + 3 design. In phase II, these therapeutic activity and safety of this regimen were evaluated. Forty-nine eligible patients were enrolled. The median age was 50 years-old. Eighty percent had a KPS of 70-100. Histologies were glioblastoma (73%), anaplastic astrocytoma (22%), anaplastic oligodendroglioma (4%). In phase I, 15 patients were treated at four cohorts by TMZ plus ACNU. MTD was TMZ (150 mg/m2) plus ACNU (40 mg/m2). In phase II, 40 patients were treated at the dose of cohort 3 (MTD). Thirty-five percent of patients experienced grade 3 or 4 toxicities, mainly hematologic. The overall response rate was 11% (4/37). Sixty-eight percent (25/37) had stable disease. Twenty-two percent (8/37) showed progression. Progression-free survival (PFS) rates at 6 and 12 months were 24% (95% CI, 12-35%) and 8% (95% CI, 4-15%). Median PFS was 13 months (95% CI, 9.2-17.2 months). Overall survival (OS) at 6 and 12 were 78% (95% CI, 67-89%) and 49% (95% CI, 33-57%). Median OS was 11.8 months (95% CI, 8.2-14.5 months). This phase I/II study showed a moderate toxicity in hematology and may has a promising efficacy in OS, without inferiority in PFS.

Incidence of Pneumocystis jirovecii pneumonia after temozolomide for CNS malignancies without prophylaxis

AIMS

Prophylaxis against Pneumocystis jiroveci pneumonia (PJP) is currently recommended for patients receiving chemoradiation with temozolomide for newly diagnosed glioblastoma multiforme. At our institution, PJP prophylaxis during temozolomide treatment has not been routinely given because of the paucity of supporting data. We investigated the rate of PJP infections in our patients.

PATIENTS & METHODS

We conducted a retrospective chart review of 240 brain tumor patients treated between 1999 and 2012 with temozolomide and no PJP prophylaxis, 127 of which received concurrent chemoradiation.

RESULTS

One in 240 patients (0.4%; 95% CI: 0.01-2.00; median total dose: 7375 mg/m(2); interquartile range: 1300) were diagnosed with PJP.

CONCLUSION

There was a <1% rate of PJP for brain tumor patients treated with temozolomide until progression without PJP prophylaxis.

The treatment of glioblastomas: a systematic update on clinical Phase III trials

Glioblastomas (GBMs) are invariably associated with unavoidable tumor recurrence and overall poor prognosis. The present study is to summarize the results of clinical Phase III studies on GBMs over the past seven years. A systematic literature search was performed using major electronic databases and by screening meeting abstracts. Totally, 16 studies of patients with newly diagnosed GBMs, recurrent GBMs, and elderly patients with GBMs were selected for this review. Although the outcomes of the experimental therapies were not encouraging, these studies produced a considerable amount of potentially clinically relevant information. Such aspects as surgical outcomes, radiation schedules, temozolomide (TMZ) schedules, methylation status of the O6-methylguanine DNA methyltransferase (MGMT) gene, combination of therapies, novel drug delivery methods and use of targeted agents have come to light and are being addressed here. In addition, we discuss the existing controversies of (1) surgical studies, (2) evaluations of recurrence, (3) salvage treatment bias, and (4) studies on elderly patients.

Standards of care for treatment of recurrent glioblastoma--are we there yet?

Newly diagnosed glioblastoma is now commonly treated with surgery, if feasible, or biopsy, followed by radiation plus concomitant and adjuvant temozolomide. The treatment of recurrent glioblastoma continues to be a moving target as new therapeutic principles enrich the standards of care for newly diagnosed disease. We reviewed PubMed and American Society of Clinical Oncology abstracts from January 2006 to January 2012 to identify clinical trials investigating the treatment of recurrent or progressive glioblastoma with nitrosoureas, temozolomide, bevacizumab, and/or combinations of these agents. At recurrence, a minority of patients are eligible for second surgery or reirradiation, based on appropriate patient selection. In temozolomide-pretreated patients, progression-free survival rates at 6 months of 20%-30% may be achieved either with nitrosoureas, temozolomide in various dosing regimens, or bevacizumab. Combination regimens among these agents or with other drugs have not produced evidence for superior activity but commonly produce more toxicity. More research is needed to better define patient profiles that predict benefit from the limited therapeutic options available after the current standard of care has failed.

In vivo selection of autologous MGMT gene-modified cells following reduced-intensity conditioning with BCNU and temozolomide in the dog model

Chemotherapy with 1,3-bis (2-chloroethyl)-1-nitrosourea (BCNU) and temozolomide (TMZ) is commonly used for the treatment of glioblastoma multiforme (GBM) and other cancers. In preparation for a clinical gene therapy study in patients with glioblastoma, we wished to study whether these reagents could be used as a reduced-intensity conditioning regimen for autologous transplantation of gene-modified cells. We used an MGMT(P140K)-expressing lentivirus vector to modify dog CD34(+) cells and tested in four dogs whether these autologous cells engraft and provide chemoprotection after transplantation. Treatment with O(6)-benzylguanine (O6BG)/TMZ after transplantation resulted in gene marking levels up to 75%, without significant hematopoietic cytopenia, which is consistent with hematopoietic chemoprotection. Retrovirus integration analysis showed that multiple clones contribute to hematopoiesis. These studies demonstrate the ability to achieve stable engraftment of MGMT(P140K)-modified autologous hematopoietic stem cells (HSCs) after a novel reduced-intensity conditioning protocol using a combination of BCNU and TMZ. Furthermore, we show that MGMT(P140K)-HSC engraftment provides chemoprotection during TMZ dose escalation. Clinically, chemoconditioning with BCNU and TMZ should facilitate engraftment of MGMT(P140K)-modified cells while providing antitumor activity for patients with poor prognosis glioblastoma or alkylating agent-sensitive tumors, thereby supporting dose-intensified chemotherapy regimens.

Anaplastic gliomas: radiation, chemotherapy, or both?

The optimal treatment of anaplastic gliomas is controversial. Options for treatment include radiation, chemotherapy or a combination of modalities. This article describes how treatment algorithms for anaplastic gliomas have evolved and interprets the results of recent studies. The available evidence indicates that patients can be treated with either chemotherapy or radiation as initial therapy, with use of the other treatment modality at relapse. Whether subpopulations exist for whom one treatment modality is superior to the other at initial diagnosis must be studied prospectively.

Radiotherapy and temozolomide in anaplastic astrocytoma: a retrospective multicenter study by the Central Nervous System Study Group of AIRO (Italian Association of Radiation Oncology)

Although the evidence for the benefit of adding temozolomide (TMZ) to radiotherapy (RT) is limited to glioblastoma patients, there is currently a trend toward treating anaplastic astrocytomas (AAs) with combined RT + TMZ. The aim of the present study was to describe the patterns of care of patients affected by AA and, particularly, to compare the outcome of patients treated exclusively with RT with those treated with RT + TMZ. Data of 295 newly diagnosed AAs treated with postoperative RT ± TMZ in the period from 2002 to 2007 were reviewed. More than 75% of patients underwent a surgical removal. All the patients had postoperative RT; 86.1% of them were treated with 3D-conformal RT (3D-CRT). Sixty-seven percent of the entire group received postoperative chemotherapy with TMZ (n = 198). One-hundred sixty-six patients received both concomitant and sequential TMZ. Prescription of postoperative TMZ increased in the most recent period (2005-2007). One- and 4-year survival rates were 70.2% and 28.6%, respectively. No statistically significant improvement in survival was observed with the addition of TMZ to RT (P = .59). Multivariate analysis showed the statistical significance of age, presence of seizures, Recursive Partitioning Analysis classes I-III, extent of surgical removal, and 3D-CRT. Changes in the care of AA over the past years are documented. Currently there is not evidence to justify the addition of TMZ to postoperative RT for patients with newly diagnosed AA outside a clinical trial. Results of prospective and randomized trials are needed.

Temozolomide: The evidence for its therapeutic efficacy in malignant astrocytomas

Introduction:

Malignant gliomas are a heterogeneous group of primary central nervous system neoplasms that represent less than 2% of all cancers yet carry a significant burden to society. They are frequently associated with considerable and progressive neurological disability and are ultimately intractable to all forms of treatment. Temozolomide (TMZ) is a new second generation DNA alkylating agent that has become part of malignant astrocytoma management paradigms because of its proven efficacy, ease of administration, and favorable toxicity profile.

Aims:

To review the role of TMZ in the management of malignant astrocytomas (World Health Organization grades III and IV) including newly diagnosed (n) and recurrent (r) anaplastic astrocytomas (AA) and glioblastomas.

Evidence review:

A series of pivotal clinical trials have established a role for TMZ in the treatment of malignant astrocytomas. A large phase II trial examining the role of TMZ in rAA showed a response rate of 35%, and a 6-month progression-free survival of 46%. This led to the accelerated approval of TMZ by the FDA and the EU for the treatment of rAA. Evidence for a role of TMZ in nAA is currently limited but research is ongoing in this area. The role of TMZ in the management of glioblastoma at the time of recurrence (rGBM) is less impressive but evidence for its activity was demonstrated in two large phase II trials that led to the approval of TMZ for this indication in Europe and Canada but not in the US. A recent large prospective randomized phase III trial showed that the addition of TMZ during and after radiation therapy (RT) in newly diagnosed (nGBM) patients prolonged median overall survival by 2.5 months; perhaps more importantly, the 2-year survival rate for patients receiving TMZ and RT was 26% compared with 10% for those receiving RT alone. Concurrent TMZ with RT followed by adjuvant TMZ has become the standard of care for nGBM patients. Based on the evidence presented in this trial, TMZ received approval from the FDA and the EU for patients with nGBM in 2005.

Place in therapy:

There is evidence to support the use of TMZ for the following diseases in the order of most to least convincing: nGBM, rAA, rGBM, and nAA. This order may quickly change as more trials are being designed and implemented, particularly with novel TMZ dosing schedules.

Recurrent pituitary ependymoma: a complex clinical problem

Ependymomas rarely arise from the region of the pituitary fossa, with only four cases previously reported in the literature. We present a complex case of a recurrent ependymoma of the parasellar region which has been difficult to clinically manage due to its tendency to recurrence. Our patient has had four operations over the last 28 years, with external beam radiotherapy, but still has residual tumor and is currently panhypopituitary and with significant visual loss. We believe there is considerable uncertainty as to the optimal management of any future progression, which seems likely, and are currently considering the use of radiosurgery with careful sparing of the optic chiasm, or possibly the chemotherapeutic agent temozolomide. Our case emphasises the recurrent nature of this rare but difficult tumor.

Phase II trial of low-dose continuous (metronomic) treatment of temozolomide for recurrent glioblastoma

The prognosis for patients with recurrent glioblastomas (GBMs) is dismal, with a median survival of 3-6 months. We performed a phase II trial of low-dose continuous (metronomic) treatment using temozolomide (TMZ) for recurrent GBMs. TMZ-refractory patients with GBM who experienced disease recurrence or progression during or after the cyclic treatment schedule of TMZ after surgery and standard radiotherapy were eligible. This phase II trial included 2 cohorts of patients. The initial cohort, comprising 10 patients, received TMZ at 40 mg/m(2) everyday. After this regimen seemed safe and effective, the metronomic schedule was changed to 50 mg/m(2) everyday. The second cohort, comprising 28 patients, received TMZ at 50 mg/m(2) everyday. The 6-month progression-free survival in all 38 patients was 32.5% (95% CI: 29.3%-35.8%) and the 6-month overall survival was 56.0% (95% CI: 36.2%-75.8%). One patient developed a grade III neutropenia, grade II thrombocytopenia in 3 patients, and grade II increase of liver enzyme (GOT/GPT) in 3 patients. Of all patients included in this study, 4 patients were withdrawn from this study because of side effects including sustained hematological disorders, cryptococcal infection, and cellulitis. In a response group, quality of life measured with short form-36 was well preserved, when compared with the pretreatment status. Metronomic treatment of TMZ is an effective treatment for recurrent GBM that is even refractory to conventional treatment of TMZ and has acceptable toxicity.

Targeting DNA repair pathways: a novel approach to reduce cancer therapeutic resistance

Increased chemo-resistance and radio-resistance of cancer cells is a major obstacle in the treatment and management of malignant cancers. An important mechanism that underlies the development of such therapeutic resistance is that cancer cells recognize DNA lesions induced by DNA-damaging agents and by ionizing radiation, and repair these lesions by activating various DNA repair pathways. Therefore, Use of pharmacological agents that can inhibit certain DNA repair pathways in cancer cells has the potential for enhancing the targeted cytotoxicity of anticancer treatments and reversing the associated therapeutic resistance associated with DNA repair; such agents, offering a promising opportunity to achieve better therapeutic efficacy. Here we review the major DNA repair pathways and discuss recent advances in the development of novel inhibitors of DNA repair pathways; many of these agents are under preclinical/clinical investigation.

Selective Lymphopenia and Opportunistic Infections in Neuroendocrine Tumor Patients Receiving Temozolomide

Temozolomide is utilized as a treatment for a variety of solid tumors and has been associated with the development of selective lymphopenia. We evaluated the incidence of lymphopenia and opportunistic infections during treatment and up to 12 months following treatment discontinuation in a cohort of 39 patients receiving temozolomide for advanced neuroendocrine tumors. The incidence of Grade 3-4 lymphopenia was 46 percent after 4 months of therapy and remained at 30 percent or greater for 12 months following treatment discontinuation. The overall incidence of opportunistic infections was 10 percent, while among patients receiving therapy for > or =7 months, the incidence was 20 percent. Prophylaxis for Pneumocystis jiroveci pneumonia and varicella-zoster, as well as cytomegalovirus monitoring, should be considered in patients receiving temozolomide-based treatment.

Glutathione disulfide induces neural cell death via a 12-lipoxygenase pathway

Oxidized glutathione (GSSG) is commonly viewed as a byproduct of GSH metabolism. The pathophysiological significance of GSSG per se remains poorly understood. Adopting a microinjection approach to isolate GSSG elevation within the cell, this work identifies that GSSG can trigger neural HT4 cell death via a 12-lipoxygenase (12-Lox)-dependent mechanism. In vivo, stereotaxic injection of GSSG into the brain caused lesion in wild-type mice but less so in 12-Lox knockout mice. Microinjection of graded amounts identified 0.5 mM as the lethal [GSSG]i in resting cells. Interestingly, this threshold was shifted to the left by 20-fold (0.025 mM) in GSH-deficient cells. This is important because tissue GSH lowering is commonly noted in the context of several diseases as well as in aging. Inhibition of GSSG reductase by BCNU is known to result in GSSG accumulation and caused cell death in a 12-Lox-sensitive manner. GSSG S-glutathionylated purified 12-Lox as well as in a model of glutamate-induced HT4 cell death in vitro where V5-tagged 12-Lox was expressed in cells. Countering glutamate-induced 12-Lox S-glutathionylation by glutaredoxin-1 overexpression protected against cell death. Strategies directed at improving or arresting cellular GSSG clearance may be effective in minimizing oxidative stress-related tissue injury or potentiating the killing of tumor cells, respectively.

Anesthetic pentobarbital inhibits proliferation and migration of malignant glioma cells

Malignant gliomas are common and aggressive brain tumors in adults. The rapid proliferation and diffuse brain migration are main obstacles to successful treatment. Here we show that pentobarbital, a central depressant introduced clinically a century ago, is capable of suppressing proliferation and migration of C6 malignant glioma cells in a concentration-dependent manner. Pentobarbital also leads to a G1 phase cell cycle arrest accompanied by suppressed G1 cell cycle regulatory proteins Cyclin D1, Cyclin D3, CDK2 and phosphorylated Rb. In addition, noticeable morphological changes and interrupted alpha-tubulin microtubule assembly are induced by pentobarbital exposure. Intracellular signal pathways involved in the effect of pentobarbital is concerned with inactivation of ERK, c-Jun and Akt. Together, these findings suggest anti-proliferation and anti-migration effects of pentobarbital on malignant gliomas, most likely by arresting cell cycle and interfering microtubule. ERK, c-Jun MAPK and PI3K/Akt are possible signaling pathways involved.

Cisplatinum and BCNU chemotherapy in primary glioblastoma patients

BACKGROUND

The prognosis of patients with glioblastoma is very poor with a mean survival of 10-12 months. Currently available treatment options are multimodal, which include surgery, radiotherapy, and chemotherapy. However, these have been shown to improve survival only marginally in glioblastoma multiforme (GBM) patients. Methylated methylguanine methyltransferase (MGMT) promoter is correlated with improved progression-free and overall survival in patients treated with alkylating agents. Strategies to overcome MGMT-mediated chemoresistance are being actively investigated.

METHODS

A retrospective analysis on 160 adult patients (> or =16 years) treated for histologically confirmed GBM between 2003 and 2005 at our Institution was performed. All patients were treated with conventional fractionated radiotherapy and a combined chemotherapy treatment with Cisplatin (CDDP) (100 mg/sqm on day 1) and carmustine (BCNU) (160 mg/sqm on day 2); the treatment was repeated every 6 weeks for five cycles. Toxicity, progression free survival and overall survival were assessed.

RESULTS

The median number of chemotherapy cycles delivered to each patient was 5 (range 3-6), with no patients discontinuing treatment because of refusal or toxicity. Dose reduction was required in 16 patients (10%), and all patients completed radiotherapy, whereas 5 patients discontinued chemotherapy before completing all planned cycles for disease progression. The primary toxicities were: neutropenia (grade 3-4: 23%), thrombocytopenia (grade 3-4: 18.5%), and nausea and vomiting (13%). Median progression-free survival times and 1-year progression free survival were 7.6 months (95% CI 6.6-8.5) and 17.3%, respectively. OS was 15.6 months (95% CI 14.1-17.1).

CONCLUSIONS

Our results for PFS and overall survival are comparable with those obtained with temozolomide, but the toxicity occurring in our series was more frequent and persistent. The toxicity, and mainly the modalities of administration associated with cisplatin and BCNU combination, argues against future use in the treatment of patients with GBM.

Opportunistic cytomegalovirus infection in a patient receiving temozolomide for treatment of malignant glioma

Treatment of malignant gliomas has changed substantially over the last few years. An oral alkylating agent, temozolomide, has become the standard agent for glioma management. Although it is generally well tolerated, it can cause lymphopenia and may lead to opportunistic infections. We report on a patient with malignant glioma who developed opportunistic cytomegalovirus (CMV) pneumonia following the termination of temozolomide therapy. The patient was admitted with acute dyspnea, fever and hypoxia, and she was diagnosed with CMV pneumonitis using a PCR-based CMV-DNA analysis. After treatment with ganciclovir, she recovered dramatically. To our knowledge, although there have been reported cases of Pneumocystis carinii infection associated with temozolomide therapy, there has only been one other case of CMV infection. We also review this report.

Localized BCNU chemotherapy and the multimodal management of malignant glioma

BACKGROUND

Gliomas account for 42% of all primary CNS neoplasms and 77% of all malignant primary CNS neoplasms. Unfortunately the high-grade variant of gliomas, glioblastoma multiforme (GBM), is difficult to treat and generally considered incurable. Survival rates are generally poor, and neurological morbidity in the setting of disease progression is high. Fortunately, significant progress has been achieved in the past decade in our understanding of the molecular biology of this aggressive tumour histology and, as a consequence, there is renewed clinical trial activity in this area focused on improving quality of life, treatment-related morbidity and outcomes.

METHODS

A review of literature from June 2005 to June 2008 was conducted on multimodal treatment of malignant glioma (MG) patients, using specific search criteria in Medline, EMBASE, and BIOSIS. Abstracts from relevant US and European medical (cancer) meetings were also evaluated.

RESULTS

The established therapies for MG include surgery, radiotherapy (RT), and local or systemic chemotherapy. However, over the last 10 years only two chemotherapeutic agents have received regulatory approval for treatment of MG: polifeprosan 20 with carmustine (BCNU implant) and temozolomide (TMZ), an imidazotetrazine derivative of dacarbazine. More recent advances in the treatment of brain tumours have been in the development of multimodal approaches. Specific interest in the combination of BCNU implant and TMZ has arisen due to the demonstrable depletion by TMZ of the DNA repair enzyme responsible for resistance to a nitrosourea such as BCNU. Further interest in this combination stems from the observation that there is a difference in the time to peak effect for each agent. Additional emerging data suggest that multimodal therapy with maximal resection and BCNU implants, followed by adjuvant therapy with radiation and TMZ, is effective and well-tolerated in patients with initial high-grade, resectable MG.

CONCLUSIONS

The increasing body of efficacy data suggests that this combination of BCNU implants and TMZ within a multimodal treatment strategy including surgery and RT may provide an enhanced benefit compared with the use of either of these agents alone in select patients with high-grade glioma.

Pharmacotherapy for adults with tumors of the central nervous system

Tumors of the adult central nervous system are among the most common and most chemoresistant neoplasms. Malignant tumors of the brain and spinal cord collectively account for approximately 1.3% of all cancers and 2.2% of all cancer-related deaths. Novel pharmacological approaches to nervous system tumors are urgently needed. This review presents the current approaches and challenges to successful pharmacotherapy of adults with malignant tumors of the central nervous system and discusses novel approaches aimed at overcoming these challenges.

Neurooncology clinical trial design for targeted therapies: lessons learned from the North American Brain Tumor Consortium

The North American Brain Tumor Consortium (NABTC) is a multi-institutional consortium with the primary objective of evaluating novel therapeutic strategies through early phase clinical trials. The NABTC has made substantial changes to the design and methodology of its trials since its inception in 1994. These changes reflect developments in technology, new types of therapies, and advances in our understanding of tumor biology and biological markers. We identify the challenges of early clinical assessment of therapeutic agents by reviewing the clinical trial effort of the NABTC and the evolution of the protocol template used to design trials. To better prioritize effort and allocation of patient resources and funding, we propose an integrated clinical trial design for the early assessment of efficacy of targeted therapies in neurooncology. This design would mandate tissue acquisition prior to therapeutic intervention with the drug, allowing prospective evaluation of its effects. It would also include a combined phase 0/I pharmacokinetic study to determine the safety and biologically optimal dose of the agent and to verify successful modulation of the target prior to initiating a larger, phase II efficacy study.

Increased oxidative stress created by adenoviral MnSOD or CuZnSOD plus BCNU (1,3-bis(2-chloroethyl)-1-nitrosourea) inhibits breast cancer cell growth

Superoxide dismutases (SODs) have been found to decrease tumor formation and angiogenesis. SOD gene therapy, as with many other gene transfer strategies, may not completely inhibit tumor growth on its own. Thus, concomitant therapies are necessary to completely control the spread of this disease. We hypothesized that intratumoral injection of AdSOD in combination with 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) chemotherapy would synergistically inhibit breast cancer growth. Our data indicate that BCNU when combined with SOD overexpression increased oxidative stress as suggested by elevated glutathione disulfide (GSSG) production in one of three breast cancer cell lines tested, at least in part due to glutathione reductase (GR) inactivation. The increased oxidative stress caused by BCNU combined with adenovirally expressed SODs, manganese or copper zinc SOD, decreased growth and survival in the three cell lines tested in vitro, but had the largest effect in the MDA-MB231 cell line, which showed the largest amount of oxidative stress. Delivery of MnSOD and BCNU intratumorally completely inhibited MDA-MB231 xenograft growth and increased nude mouse survival in vivo. Intravenous (iv) BCNU, recapitulating clinical usage, and intratumoral AdMnSOD delivery, to provide tumor specificity, provided similar decreased growth and survival in our nude mouse model. This cancer therapy produced impressive results, suggesting the potential use of oxidative stress-induced growth inhibitory treatments for breast cancer patients.

New developments in the treatment of malignant gliomas

Malignant gliomas represent an heterogeneous group of brain tumors both in terms of natural history and response to treatment. The standard therapeutic approach for treating glioblastomas is a combination of radiotherapy and concomitant/adjuvant temozolomide, and methylguanine-DNA methyltransferase promoter methylation is now recognized as an important factor for predicting both prognosis and response to alkylating agents. In the future, the discovery of targeted therapies will increasingly allow personalized medical treatments. Anaplastic oligodendroglial tumors display a better prognosis and are more chemosensitive than glioblastomas; the discovery of molecular factors of prognostic significance, such as 1p/19q codeletion, will lead to different treatment strategies for different subgroups of patients. Gliomatosis cerebri is a rare diffuse glioma, and upfront chemotherapy is increasingly being employed instead of whole-brain radiotherapy to avoid/delay cognitive defects in long surviving patients, despite the lack of data to support this.

Molecular targeted therapies and chemotherapy in malignant gliomas

PURPOSE OF REVIEW

To review current developments in the field of chemotherapy and targeted treatment of high-grade glioma.

RECENT FINDINGS

Two independent large phase III trials on adjuvant procarbazine, lomustine and vincristine chemotherapy in anaplastic oligodendroglial tumors have shown this improves progression-free survival, but not overall survival, regardless of 1p/19q status. If given sequentially, the timing of procarbazine, lomustine and vincristine chemotherapy has no clear effect on the survival of anaplastic oligodendroglioma. Virtually none of the many new targeted agents directed against pathways that are upregulated in high-grade gliomas has shown significant clinical activity as single agent in phase II studies. The exception are trials with the vascular endothelial growth factor signaling system inhibiting agents bevacizumab and AZD2171 (cediranib) that showed high response rates (which might be due to vessel normalization similar to the effects of steroid treatment) and promising 6-month progression-free survival rates in glioblastoma multiforme.

SUMMARY

Further research to define the role of vascular endothelial growth factor inhibition in the management is indicated. For the many other targeted agents, a critical review of the pathological role of their targets in glioblastoma multiforme is required, especially if combination regimens are investigated. The role of combined chemo-irradiation for non-glioblastoma multiforme high-grade glioma remains to be identified.

New chemotherapy options for the treatment of malignant gliomas

This review focuses on the recent advances in chemotherapy of malignant gliomas, with special emphasis on the most common primary brain tumor in adults, glioblastoma. The demonstration of the superiority of concomitant and adjuvant temozolomide with standard radiotherapy over radiotherapy alone in patients with newly diagnosed glioblastomas by means of phase III international trial has been the major advance in the care of these patients so far. Moreover, patients whose tumors display the hypermethylation of the promoter of the gene for the repairing enzyme O-methylguanine-DMA methyltransferase are most likely to benefit from the combination regimen. The advantage of a postsurgical local administration of carmustine by slow-release polymers ('gliadel wafers') is more modest, and the efficacy and safety of a sequence of carmustine wafers followed by temozolomide combined with radiotherapy remain to be defined. Different DNA repair modulation strategies are being investigated to further improve the results: dose-dense regimens of temozolomide, combination of temozolomide with specific inhibitors of O-methylguanine-DMA methyltransferase and combination of temozolomide with specific inhibitors of base excision repair [poly(ADP-ribose) polymerase inhibitors]. Other developments include the combination of cytotoxic, cytostatic and targeted therapies. Multitargeted compounds that simultaneously affect multiple signaling pathways, such as those involving epidermal growth factor receptor, platelet-derived growth factor receptor and vascular endothelial growth factor receptor, are increasingly employed. In the future, innovative trial designs (factorial and adaptative designs), pretreatment molecular profiling of individual tumors and the adoption of biological end-points (changes in serum tumor markers, measures of target inhibition), in addition to the traditional clinical and radiographic end-points, will be needed to achieve further advances.

Salvage chemotherapy with procarbazine and fotemustine combination in the treatment of temozolomide treated recurrent glioblastoma patients

The purpose of this study was to evaluate safety and efficacy of Procarbazine (PCB) and fotemustine (FTM) combination in the treatment of pre-temozolomide treated, recurrent GBM patients. The primary end-point was progression free survival at 6 months (PFS-6). Secondary end-points were overall survival, response rates (CR + PR) and toxicity. About 54 patients (41 men and 13 women) aged 26-68 years (median age, 53.5 years) with recurrent GBM were treated. PCB was administered as an oral dosage of 450 mg on days 1-2 and a total dose of 300 mg on day 3. FTM was administered on day 3, 3 h after the last PCB intake at a dose of 110 mg/mq/BSA. The treatment was repeated every 5 weeks. Treatment was continued for a maximum of six cycles or until disease progression. After two cycles of chemotherapy: 6 patients (11.2%) experienced a neuroradiographic partial response (PR), 29 patients (53.7%) had stable disease (SD), and 19 patients (35.1%) had progressive disease (PD). For the whole group of patients, the median PFS was 19.3 weeks (95% CI, 14.1-24.4 weeks), and PFS-6 was 26.7% (95% CI, 10.6-42.8%). Overall MST from the beginning of PCB + FTM chemotherapy was 28.7 weeks (95% CI, 24.8-32.7 weeks). At 6 and 12 months, 64.4% (95% CI, 51.5-77.3%) and 23.6% (95% CI, 10.1-37.1%) of patients were alive. The median survival time calculated from the first diagnosis was 20.8 months (95% CI, 16.7-24.8). We concluded that the PCB + FTM combination as done in the current trial for patients with recurrent GBM after treatment with TMZ showed some benefit with regards to increased survival and that a Phase III trial is warranted.

Recent advances in the medical therapy of high-grade gliomas

Malignant glial neoplasms, including glioblastoma, are amongst the most devastating and intractable of solid tumors. Until recently the standard of care for newly diagnosed glioblastoma was surgical resection to the extent feasible followed by conventional fractionated radiotherapy. When administered for disease progression, chemotherapy had modest benefit and its use in the adjuvant setting was controversial. Temozolomide, an oral alkylating chemotherapeutic agent, has now been demonstrated to increase survival time in patients with newly diagnosed glioblastoma when used concurrently with radiotherapy and as adjuvant or maintenance treatment for six cycles thereafter. Correlative molecular studies suggested that the benefit of temozolomide is largely restricted to patients whose tumor has silenced the gene for methylguanine methyltransferase, a repair enzyme implicated in resistance to alkylator chemotherapy. Use of temozolomide chemotherapy upfront in the management of glioblastoma is now considered the standard of care. This significant advance has also stimulated development of therapeutic strategies that incorporate temozolomide, and other agents, in the initial management of most high-grade gliomas. Furthermore, our increased understanding of the molecular derangements that underlie gliomagenesis has identified a number of putative molecular targets against which novel therapeutics have been tested with encouraging preliminary results. Finally, the challenges presented by the blood–brain barrier to adequate drug delivery have stimulated the development of unique locoregional delivery techniques that are currently undergoing clinical evaluation. This review summarizes these recent advances, and speculates on how the field is likely to evolve in the near future.

Phase II trial of lomustine plus temozolomide chemotherapy in addition to radiotherapy in newly diagnosed glioblastoma: UKT-03

PURPOSE

To evaluate toxicity and efficacy of the combination of lomustine, temozolomide (TMZ) and involved-field radiotherapy in patients with newly diagnosed glioblastoma (GBM).

PATIENTS AND METHODS

Thirty-one adult patients (median Karnofsky performance score 90; median age, 51 years) accrued in two centers received involved-field radiotherapy (60 Gy in 2-Gy fractions) and chemotherapy with lomustine 100 mg/m2 (day 1) and TMZ 100 mg/m2/d (days 2 to 6) with individual dose adjustments according to hematologic toxicity.

RESULTS

A median of five courses (range, one to six courses) were delivered. WHO grade 4 hematotoxicity was observed in five patients (16%) and one of these patients died as a result of septicemia. Nonhematologic toxicity included one patient with WHO grade 4 drug-induced hepatitis (leading to discontinuation of lomustine and TMZ) and one patient with WHO grade 2 lung fibrosis (leading to discontinuation of lomustine). The progression-free survival (PFS) rate at 6 months was 61.3%. The median PFS was 9 months (95% CI, 5.3 to 11.7 months), the median overall survival time (MST) was 22.6 months (95% CI, 12.5 to not assessable), the 2-year survival rate was 44.7%. O6-methylguanine-DNA methyltransferase (MGMT) gene-promoter methylation in the tumor tissue was associated with longer PFS (P = .014, log-rank test) and MST (P = .037).

CONCLUSION

The combination of lomustine, TMZ, and radiotherapy had acceptable toxicity and yielded promising survival data in patients with newly diagnosed GBM. MGMT gene-promoter methylation was a strong predictor of survival.

Temozolomide: a milestone in neuro-oncology and beyond?

Temozolomide (Temodal, Temodar), an imidazol derivative, is a second-generation alkylating agent. The orally available prodrug with the capacity of crossing the blood-brain barrier received accelerated US FDA approval in 1999. Three pivotal Phase II trials showed modest activity in the treatment of recurrent anaplastic astrocytoma glioblastoma. In 2005, the FDA and the European Agency for the Evaluation of Medicinal Products approved temozolomide for use in newly diagnosed glioblastoma, in conjunction with radiotherapy, based on an European Organisation for Research and Treatment of Cancer/National Cancer Institute of Canada Phase III trial. The adverse events associated with temozolomide are mild-to-moderate and generally predictable; the most serious are noncumulative and reversible myelosuppression and, in particular, thrombocytopenia, which occurs in less than 5% of patients. Continuous temozolomide administration is associated with profound CD4-selective lymphocytopenia. Molecular studies have suggested that the benefit of temozolomide chemotherapy is restricted to patients whose tumors have a methylated methylguanine methyltransferase gene promotor and are thus unable to repair some of the chemotherapy-induced DNA damage. Temozolomide is under investigation for other disease entities, in particular lower-grade glioma, brain metastases and melanoma.

Temozolomide for recurrent or progressive high-grade malignant glioma: results of an Austrian multicenter observational study

BACKGROUND

The use of chemotherapy in patients with malignant gliomas has remained a controversial issue even after the publication of favorable study data and a meta-analysis. The present study was initiated to support the use of chemotherapy in patients with relapsed high-grade gliomas (HGG).

PATIENTS AND METHODS

Six Austrian centers recruited 43 patients with histologically confirmed HGG at first recurrence. Twelve chemotherapy-naïve patients received oral temozolomide at a dose of 200 mg/m(2) once a day for five consecutive days and 26 patients a dose of 150 mg/m(2) also for five days after various first-line chemotherapies. TMZ treatment was repeated every four weeks for a total of six cycles.

RESULTS

Twenty-one patients (52.5 %) received at least six cycles of therapy. Two patients experienced complete remission and eight patients a partial response. Twenty patients survived at one year after enrolment in the study; eight patients survived beyond three years of follow-up. Hematological toxicities consisted of three thrombocytopenias G4 and 35 lymphocytopenias G3 and G4; these did not cause interstitial pneumonia or require inpatient treatment. Non-hematological toxicities were rare and without clinical relevance. Patients' quality of life was maintained during treatment.

CONCLUSION

The study data confirm the feasibility and efficacy of chemotherapy with temozolomide in patients with relapsed/progressive HGG.

Changing Paradigms—An Update on the Multidisciplinary Management of Malignant Glioma

Treatment of malignant glioma requires a multidisciplinary team. Treatment includes surgery, radiotherapy, and chemotherapy. Recently developed agents have demonstrated activity against recurrent malignant glioma and efficacy if given concurrently with radiotherapy in the upfront setting. Oligodendroglioma with 1p/19q deletions has been recognized as a distinct pathologic entity with particular sensitivity to radiotherapy and chemotherapy. Randomized trials have shown that early neoadjuvant or adjuvant administration of procarbazine, lomustine, and vincristine chemotherapy prolongs disease-free survival; however, it has no impact on overall survival. Temozolomide, a novel alkylating agent, has shown modest activity against recurrent glioma. In combination with radiotherapy in newly diagnosed patients with glioblastoma, temozolomide significantly prolongs survival. Molecular studies have demonstrated that the benefit is mainly observed in patients whose tumors have a methylated methylguanine methyltransferase gene promoter and are thus unable to repair some of the chemotherapy-induced DNA damage. For lower-grade glioma, the use of chemotherapy remains limited to recurrent disease, and first-line administration is the subject of ongoing clinical trials. Irinotecan and agents like gefitinib, erlotinib, and imatinib targeting the epidermal growth factor receptor and platelet-derived growth factor receptor have shown some promise in recurrent malignant glioma. This review summarizes recent developments, focusing on the clinical management of patients in daily neuro-oncology practice.

The emerging role of DNA repair proteins as predictive, prognostic and therapeutic targets in cancer

Advanced cancer is the second leading cause of death in the western world. Chemotherapy and radiation are the two main treatment modalities currently available to improve patient outcomes, but treatment related toxicity and the emergence of resistance limit their effectiveness. Hence there is an urgent need to develop novel treatment strategies. Rapid advances in cancer biology have identified key pathways involved in the repair of DNA damage induced by chemotherapeutic agents and irradiation. Efficient DNA repair in the cancer cell is an important mechanism for therapeutic resistance. Up to 130 genes have been identified that are associated with human DNA repair. Several of these proteins are emerging as important predictive and prognostic factors in solid tumours. Inhibition of DNA repair has the potential to enhance the efficacy of currently available DNA damaging agents. In recent years, several promising drug targets have been identified and novel drugs synthesised that target specific DNA repair proteins. These agents have shown impressive anti-cancer effects in preclinical studies in combination with chemotherapy or irradiation. Their role in human cancer is now being investigated in early phase clinical trials in combination with chemotherapy. MGMT inhibitors, PARP inhibitors and methoxyamine are currently in early stages of clinical development. Innovative clinical trial designs are essential to evaluate the potential of DNA repair inhibitor in cancer therapy.

DNA repair inhibition: a selective tumour targeting strategy

Advanced cancer is a leading cause of death in the developed world. Chemotherapy and radiation are the two main treatment modalities currently available. The cytotoxicity of many of these agents is directly related to their propensity to induce DNA damage. However, the ability of cancer cells to recognize this damage and initiate DNA repair is an important mechanism for therapeutic resistance and has a negative impact upon therapeutic efficacy. Pharmacological inhibition of DNA repair, therefore, has the potential to enhance the cytotoxicity of a diverse range of anticancer agents. Moreover, the use of inhibitors of DNA repair or DNA damage signalling pathways appears to provide an exciting opportunity to target the genetic differences that exist between normal and tumour tissue.

Phase I Trial of Temozolomide PlusO6-Benzylguanine for Patients With Recurrent or Progressive Malignant Glioma

Purpose

We conducted a two-phase clinical trial in patients with progressive malignant glioma (MG). The first phase of this trial was designed to determine the dose of O6-BG effective in producing complete depletion of tumor AGT activity for 48 hours. The second phase of the trial was designed to define the maximum tolerated dose (MTD) of a single dose of temozolomide when combined with O6-BG. In addition, plasma concentrations of O6-BG and O6-benzyl-8-oxoguanine were evaluated after O6-BG.

Patients and Methods

For our first phase of the clinical trial, patients were scheduled to undergo craniotomy for AGT determination after receiving a 1-hour O6-BG infusion at 120 mg/m2followed by a continuous infusion at an initial dose of 30 mg/m2/d for 48 hours. The dose of the continuous infusion of O6-BG escalated until tumor AGT was depleted. Once the O6-BG dose was established a separate group of patients was enrolled in the second phase of clinical trial, in which temozolomide, administered as a single dose at the end of the 1-hour O6-BG infusion, was escalated until the MTD was determined.

Results

The O6-BG dose found to be effective in depleting tumor AGT activity at 48 hours was an IV bolus of 120 mg/m2over 1 hour followed by a continuous infusion of 30 mg/m2/d for 48 hours. On enrolling 38 patients in six dose levels of temozolomide, the MTD was established at 472 mg/m2with dose-limiting toxicities limited to myelosuppression.

Conclusion

This study provides the foundation for a phase II trial of O6-BG plus temozolomide in temozolomide-resistant MG.

Optimal role of temozolomide in the treatment of malignant gliomas

Temozolomide (TMZ) is an alkylating agent that was approved for anaplastic astrocytoma and glioblastoma. Its role in the treatment of recurrent disease has been confirmed, and more importantly, alternative treatment schedules and combination regimens have been developed. A recent phase III trial has demonstrated a survival advantage for concomitant TMZ administration with radiotherapy in patients with newly diagnosed glioblastoma. Molecular studies suggest a strong predictive role of the DNA repair enzyme O6-methyl-guanine-DNA-methyl-transferase (MGMT) and outcome of TMZ-based chemotherapy. This review summarizes the current knowledge, highlights approved and nonapproved indications, and describes molecular studies that may allow us to identify the patients most likely to benefit from this treatment.

Temozolomide in combination with BCNU before and after radiotherapy in patients with inoperable newly diagnosed glioblastoma multiforme

BACKGROUND

The aim of this study was to evaluate the efficacy and safety of carmustine (BCNU) in combination with temozolomide as first-line chemotherapy before and after radiotherapy (RT) in patients with inoperable, newly diagnosed glioblastoma multiforme (GBM).

PATIENTS AND METHODS

Forty patients were treated with BCNU (150 mg/m2) on day 1 and temozolomide (110 mg/m2/day) on days 1 through 5 of each 42-day cycle for up to four cycles prior to conventional RT (2 Gy fractions to a total of 60 Gy). After RT, BCNU + temozolomide was administered for four additional cycles or until progression. The primary end point was response rate; secondary end points included progression-free survival (PFS); overall survival (OS) and safety.

RESULTS

Sixty per cent of patients completed four cycles of neo-adjuvant BCNU + temozolomide. Objective response rate (intention-to-treat) was 42.5% (95% confidence interval 27% to 58%), including two (5%) complete and 15 (37.5%) partial responses. In the eligible population (n=37) the objective response rate was 46%. Nine (24%) patients had stable disease and 14 (35%) had progressive disease. Median PFS and OS were 7.4 and 12.7 months, respectively. Age was the only significant prognostic factor and tumor location (lobar versus multifocal versus corpus callosum) showed a trend. Grade 3-4 toxicities included thrombocytopenia (n=11) and neutropenia (n=7) for both pre- and post-RT chemotherapy. Four patients required platelet transfusions. No patient discontinued treatment because of toxicity.

CONCLUSIONS

The combination of BCNU plus temozolomide as neo-adjuvant therapy in inoperable GBM exhibited promising activity with a good safety profile and warrants further evaluation.