Phase II trial of 7 days on/7 days off temozolmide for recurrent high-grade glioma

Development and characterization of a temozolomide-loaded nanoemulsion and the effect of ferrocene pre and co-treatments in glioblastoma cell models

BACKGROUND

Glioblastoma is a severe brain tumor that requires aggressive treatment involving surgery, radiotherapy, and chemotherapy, offering a survival rate of only 15 months. Fortunately, recent nanotechnology progress has enabled novel approaches and, alongside ferrocenes' unique properties of cytotoxicity, sensitization, and interaction with reactive oxygen species, have brought new possibilities to complement chemotherapy in nanocarrier systems, enhancing treatment results.

METHODS

In this work, we developed and characterized a temozolomide-loaded nanoemulsion and evaluated its cytotoxic potential in combination with ferrocene in the temozolomide-resistant T98G and temozolomide-sensitive U87 cell lines. The effects of the treatments were assessed through acute assays of cell viability, cell death, mitochondrial alterations, and a treatment protocol simulation based on different two-cycle regimens.

RESULTS

Temozolomide nanoemulsion showed a z-average diameter of 173.37 ± 0.86 nm and a zeta potential of - 6.53 ± 1.13 mV. Physicochemical characterization revealed that temozolomide is probably associated with nanoemulsion droplets instead of being entrapped within the nanostructure, allowing a rapid drug release. In combination with ferrocene, temozolomide nanoemulsion reduced glioblastoma cell viability in both acute and two-cycle regimen assays. The combined treatment approach also reversed T98G's temozolomide-resistant profile by altering the mitochondrial membrane potential of the cells, thus increasing reactive oxygen species generation, and ultimately inducing cell death.

CONCLUSIONS

Altogether, our results indicate that using nanoemulsion containing temozolomide in combination with ferrocene is an effective approach to improve glioblastoma therapy outcomes.

Effects of Reoperation Timing on Survival among Recurrent Glioblastoma Patients: A Retrospective Multicentric Descriptive Study

Glioblastoma inevitably recurs, but no standard regimen has been established for treating this recurrent disease. Several reports claim that reoperative surgery can improve survival, but the effects of reoperation timing on survival have rarely been investigated. We, therefore, evaluated the relationship between reoperation timing and survival in recurrent GBM. A consecutive cohort of unselected patients (real-world data) from three neuro-oncology cancer centers was analyzed (a total of 109 patients). All patients underwent initial maximal safe resection followed by treatment according to the Stupp protocol. Those meeting the following criteria during progression were indicated for reoperation and were further analyzed in this study: (1) The tumor volume increased by >20-30% or a tumor was rediscovered after radiological disappearance; (2) The patient's clinical status was satisfactory (KS ≥ 70% and PS WHO ≤ gr. 2); (3) The tumor was localized without multifocality; (4) The minimum expected tumor volume reduction was above 80%. A univariate Cox regression analysis of postsurgical survival (PSS) revealed a statistically significant effect of reoperation on PSS from a threshold of 16 months after the first surgery. Cox regression models that stratified the Karnofsky score with age adjustment confirmed a statistically significant improvement in PSS for time-to-progression (TTP) thresholds of 22 and 24 months. The patient groups exhibiting the first recurrence at 22 and 24 months had better survival rates than those exhibiting earlier recurrences. For the 22-month group, the HR was 0.5 with a 95% CI of (0.27, 0.96) and a p-value of 0.036. For the 24-month group, the HR was 0.5 with a 95% CI of (0.25, 0.96) and a p-value of 0.039. Patients with the longest survival were also the best candidates for repeated surgery. Later recurrence of glioblastoma was associated with higher survival rates after reoperation.

Tumor Treating Fields Combine with Temozolomide for Newly Diagnosed Glioblastoma: A Retrospective Analysis of Chinese Patients in a Single Center

Introduction: TTFields plus Temozolomide (TTFields/TMZ) extended survival versus TMZ alone in newly diagnosed glioblastoma (GBM) patients in the EF-14 trial. We have reported a retrospective analysis of newly diagnosed Chinese GBM patients who received TTFields/TMZ treatment and TMZ treatment from August 2018 to May 2021 in Huashan hospital in Shanghai. Methods: Overall survival (OS) and progression-free survival (PFS) curves were constructed using the Kaplan−Meier method. A Cox proportional hazards regression model, propensity score matched data, and inverse probability of treatment weighting (IPTW) based on propensity score were used to assess the effect of TTFields and account for confounding factors. Results: In the preliminary analysis, the median PFS in TTFields/TMZ group was 16 months (95% CI, 9.6−24.6) versus 11 months (95% CI, 9−12) in TMZ group (p < 0.05). Median overall survival was 21.8 months (95% CI, 17.4-NA) with TTFields/TMZ versus 15 months (HR = 0.43; 95% CI, 13−18) with TMZ alone. The multivariate analysis identified surgery type, STUPP scheme, IDH status, and TTFields use as favorable prognostic factors. After PSM adjustment, the variate among the groups was similar, except that the methylation rate of MGMT promoter remained high in the TMZ group (12 v 32 months; p = 0.011). Upon IPTW Survival analysis, TTFields was associated with a significantly lower risk of death (HR = 0.19 in OS; 95% CI, 0.09−0.41) and progression (HR = 0.35; 95% CI 0.14−0.9) compared with TMZ group. Conclusion: In the final analysis of our single-center Chinese patients with glioblastoma, adding TTFields to temozolomide chemotherapy resulted in statistically significant improvement in PFS and OS.

Current and promising treatment strategies in glioma

Gliomas are the most common primary central nervous system tumors; despite recent advances in diagnosis and treatment, glioma patients generally have a poor prognosis. Hence there is a clear need for improved therapeutic options. In recent years, significant effort has been made to investigate immunotherapy and precision oncology approaches. The review covers well-established strategies such as surgery, temozolomide, PCV, and mTOR inhibitors. Furthermore, it summarizes promising therapies: tumor treating fields, immune therapies, tyrosine kinases inhibitors, IDH(Isocitrate dehydrogenase)-targeted approaches, and others. While there are many promising treatment strategies, none fundamentally changed the management of glioma patients. However, we are still awaiting the outcome of ongoing trials, which have the potential to revolutionize the treatment of glioma.

The Next Frontier in Health Disparities-A Closer Look at Exploring Sex Differences in Glioma Data and Omics Analysis, from Bench to Bedside and Back

Sex differences are increasingly being explored and reported in oncology, and glioma is no exception. As potentially meaningful sex differences are uncovered, existing gender-derived disparities mirror data generated in retrospective and prospective trials, real-world large-scale data sets, and bench work involving animals and cell lines. The resulting disparities at the data level are wide-ranging, potentially resulting in both adverse outcomes and failure to identify and exploit therapeutic benefits. We set out to analyze the literature on women's data disparities in glioma by exploring the origins of data in this area to understand the representation of women in study samples and omics analyses. Given the current emphasis on inclusive study design and research, we wanted to explore if sex bias continues to exist in present-day data sets and how sex differences in data may impact conclusions derived from large-scale data sets, omics, biospecimen analysis, novel interventions, and standard of care management.

Molecular Biomarkers in Glioblastoma: A Systematic Review and Meta-Analysis

Background: Glioblastoma (GBM) is a highly aggressive cancer with poor prognosis that needs better treatment modalities. Moreover, there is a lack of reliable biomarkers to predict the response and outcome of current or newly designed therapies. While several molecular markers have been proposed as potential biomarkers for GBM, their uptake into clinical settings is slow and impeded by marker heterogeneity. Detailed assessment of prognostic and predictive value for biomarkers in well-defined clinical trial settings, if available, is scattered throughout the literature. Here we conducted a systematic review and meta-analysis to evaluate the prognostic and predictive significance of clinically relevant molecular biomarkers in GBM patients. Material and methods: A comprehensive literature search was conducted to retrieve publications from 3 databases (Pubmed, Cochrane and Embase) from January 2010 to December 2021, using specific terms. The combined hazard ratios (HR) and confidence intervals (95% CI) were used to evaluate the association of biomarkers with overall survival (OS) in GBM patients. Results: Twenty-six out of 1831 screened articles were included in this review. Nineteen articles were included in the meta-analyses, and 7 articles were quantitatively summarised. Fourteen studies with 1231 GBM patients showed a significant association of MGMT methylation with better OS with the pooled HR of 1.66 (95% CI 1.32−2.09, p < 0.0001, random effect). Five studies including 541 GBM patients analysed for the prognostic significance of IDH1 mutation showed significantly better OS in patients with IDH1 mutation with a pooled HR of 2.37 (95% CI 1.81−3.12; p < 0.00001]. Meta-analysis performed on 5 studies including 575 GBM patients presenting with either amplification or high expression of EGFR gene did not reveal any prognostic significance with a pooled HR of 1.31 (95% CI 0.96−1.79; p = 0.08). Conclusions: MGMT promoter methylation and IDH1 mutation are significantly associated with better OS in GBM patients. No significant associations were found between EGFR amplification or overexpression with OS.

Recurrent Glioblastoma Treatment: State of the Art and Future Perspectives in the Precision Medicine Era

Current treatment guidelines for the management of recurrent glioblastoma (rGBM) are far from definitive, and the prognosis remains dismal. Despite recent advancements in the pharmacological and surgical fields, numerous doubts persist concerning the optimal strategy that clinicians should adopt for patients who fail the first lines of treatment and present signs of progressive disease. With most recurrences being located within the margins of the previously resected lesion, a comprehensive molecular and genetic profiling of rGBM revealed substantial differences compared with newly diagnosed disease. In the present comprehensive review, we sought to examine the current treatment guidelines and the new perspectives that polarize the field of neuro-oncology, strictly focusing on progressive disease. For this purpose, updated PRISMA guidelines were followed to search for pivotal studies and clinical trials published in the last five years. A total of 125 articles discussing locoregional management, radiotherapy, chemotherapy, and immunotherapy strategies were included in our analysis, and salient findings were critically summarized. In addition, an in-depth description of the molecular profile of rGBM and its distinctive characteristics is provided. Finally, we integrate the above-mentioned evidence with the current guidelines published by international societies, including AANS/CNS, EANO, AIOM, and NCCN.

Congress of Neurological Surgeons systematic review and evidence-based guidelines update on the role of cytotoxic chemotherapy and other cytotoxic therapies in the management of progressive glioblastoma in adults

TARGET POPULATION

These recommendations apply to adult patients diagnosed with progressive glioblastoma (pGBM). QUESTION (Q1): In adult patients with pGBM does the use of temozolomide (TMZ) with alternative dosing or the use of TMZ in combination with other cytotoxic treatments result in increased overall survival compared to other chemotherapy?

RECOMMENDATION

Level III: Adult patients with pGBM might derive benefit in treatment with TMZ, especially those who progress after more than 5 months of TMZ-treatment free interval.

LEVEL III

Combination of TMZ with other cytotoxic agents such as nitrosourea, cisplatin, electrohyperthermia, or tamoxifen is not suggested in adult patients with pGBM as a stand-alone therapy. There is insufficient data to make a recommendation about which alternative TMZ dosing provides the best benefits. QUESTION (Q2): In adult patients with pGBM does the use of systemic or in situ nitrosourea result in increased overall survival compared to other chemotherapy?

RECOMMENDATION

Level III: In the setting of pGBM, fotemustine is suggested in elderly patients with methylated MGMT promoter status. There is insufficient evidence to compare fotemustine to other nitrosoureas. There is insufficient evidence to make a recommendation about the use of in situ nitrosourea in patients with pGBM who underwent the Stupp regimen. QUESTION (Q3): In adult patients with pGBM does the use of platinum compounds and topoisomerase result in increased survival compared to other chemotherapy?

RECOMMENDATION

Level III: Other chemotherapy including platinum compounds and topoisomerase inhibitors are not suggested to be used in adult patients with pGBM.

LEVEL III

Other cytotoxic therapies like perillyl acohol or ketogenic diet are not suggested for use in adult patients with pGBM as a stand-alone therapy. QUESTION (Q4): In adult patients with pGBM does the use of tumor treating field (TTF) result in increased overall survival compared to chemotherapy?

RECOMMENDATION

Level III: The use of TTF with other chemotherapy may be considered when treating adult patients with pGBM. There is insufficient evidence to recommend TTF to increase overall survival in adult patients with pGBM. QUESTION (Q5): In adult patients with pGBM does the use of oncolytic virotherapy result in increased survival compared to chemotherapy?

RECOMMENDATION

Level III: Oncolytic virotherapy is not suggested in patients with pGBM.

The current landscape of systemic therapy for recurrent glioblastoma: A systematic review of randomized-controlled trials

AIM

Conduct a systematic review of the effectiveness of systemic therapies for adult recurrent glioblastoma (rGBM).

METHODS

We electronically searched for randomized controlled trials from three major databases and four conferences from 2009-Dec 2020. Two independent reviewers conducted screening, data extraction, and quality assessment.

RESULTS

48 randomized trials were identified. Outcome reporting was inconsistent: overall survival (OS) in 46 studies, progression free survival in 37 studies, 6-month PFS in 30 studies, objective response rate in 28 studies, and 6-month OS in 7 studies. Network meta-analysis was not feasible due to heterogeneity in outcome reporting and single-study linkages. Most studies compared lomustine (8 studies), bevacizumab (18), or temozolomide (8) with other treatments. The median OS across all studies ranged from 3 to 17.6 months.

CONCLUSIONS

Based on level one evidence, there is no superior systemic regimen for rGBM. rGBM is a heterogeneous population with no single regimen demonstrating OS benefit. Registration number: CRD42020148512.

INTELLANCE 2/EORTC 1410 randomized phase II study of Depatux-M alone and with temozolomide vs temozolomide or lomustine in recurrent EGFR amplified glioblastoma

Background

Depatuxizumab mafodotin (Depatux-M) is a tumor-specific antibody–drug conjugate consisting of an antibody (ABT-806) directed against activated epidermal growth factor receptor (EGFR) and the toxin monomethylauristatin-F. We investigated Depatux-M in combination with temozolomide or as a single agent in a randomized controlled phase II trial in recurrent EGFR amplified glioblastoma.

Methods

Eligible were patients with centrally confirmed EGFR amplified glioblastoma at first recurrence after chemo-irradiation with temozolomide. Patients were randomized to either Depatux-M 1.25 mg/kg every 2 weeks intravenously, or this treatment combined with temozolomide 150–200 mg/m² day 1–5 every 4 weeks, or either lomustine or temozolomide. The primary endpoint of the study was overall survival.

Results

Two hundred sixty patients were randomized. In the primary efficacy analysis with 199 events (median follow-up 15.0 mo), the hazard ratio (HR) for the combination arm compared with the control arm was 0.71 (95% CI = 0.50, 1.02; P = 0.062). The efficacy of Depatux-M monotherapy was comparable to that of the control arm (HR = 1.04, 95% CI = 0.73, 1.48; P = 0.83). The most frequent toxicity in Depatux-M treated patients was a reversible corneal epitheliopathy, occurring as grades 3–4 adverse events in 25–30% of patients. In the long-term follow-up analysis with median follow-up of 28.7 months, the HR for the comparison of the combination arm versus the control arm was 0.66 (95% CI = 0.48, 0.93).

Conclusion

This trial suggests a possible role for the use of Depatux-M in combination with temozolomide in EGFR amplified recurrent glioblastoma, especially in patients relapsing well after the end of first-line adjuvant temozolomide treatment. (NCT02343406)

Prognostic value of test(s) for O6-methylguanine-DNA methyltransferase (MGMT) promoter methylation for predicting overall survival in people with glioblastoma treated with temozolomide

BACKGROUND

Glioblastoma is an aggressive form of brain cancer. Approximately five in 100 people with glioblastoma survive for five years past diagnosis. Glioblastomas that have a particular modification to their DNA (called methylation) in a particular region (the O6-methylguanine-DNA methyltransferase (MGMT) promoter) respond better to treatment with chemotherapy using a drug called temozolomide.

OBJECTIVES

To determine which method for assessing MGMT methylation status best predicts overall survival in people diagnosed with glioblastoma who are treated with temozolomide.

SEARCH METHODS

We searched MEDLINE, Embase, BIOSIS, Web of Science Conference Proceedings Citation Index to December 2018, and examined reference lists. For economic evaluation studies, we additionally searched NHS Economic Evaluation Database (EED) up to December 2014.

SELECTION CRITERIA

Eligible studies were longitudinal (cohort) studies of adults with diagnosed glioblastoma treated with temozolomide with/without radiotherapy/surgery. Studies had to have related MGMT status in tumour tissue (assessed by one or more method) with overall survival and presented results as hazard ratios or with sufficient information (e.g. Kaplan-Meier curves) for us to estimate hazard ratios. We focused mainly on studies comparing two or more methods, and listed brief details of articles that examined a single method of measuring MGMT promoter methylation. We also sought economic evaluations conducted alongside trials, modelling studies and cost analysis.

DATA COLLECTION AND ANALYSIS

Two review authors independently undertook all steps of the identification and data extraction process for multiple-method studies. We assessed risk of bias and applicability using our own modified and extended version of the QUality In Prognosis Studies (QUIPS) tool. We compared different techniques, exact promoter regions (5'-cytosine-phosphate-guanine-3' (CpG) sites) and thresholds for interpretation within studies by examining hazard ratios. We performed meta-analyses for comparisons of the three most commonly examined methods (immunohistochemistry (IHC), methylation-specific polymerase chain reaction (MSP) and pyrosequencing (PSQ)), with ratios of hazard ratios (RHR), using an imputed value of the correlation between results based on the same individuals.

MAIN RESULTS

We included 32 independent cohorts involving 3474 people that compared two or more methods. We found evidence that MSP (CpG sites 76 to 80 and 84 to 87) is more prognostic than IHC for MGMT protein at varying thresholds (RHR 1.31, 95% confidence interval (CI) 1.01 to 1.71). We also found evidence that PSQ is more prognostic than IHC for MGMT protein at various thresholds (RHR 1.36, 95% CI 1.01 to 1.84). The data suggest that PSQ (mainly at CpG sites 74 to 78, using various thresholds) is slightly more prognostic than MSP at sites 76 to 80 and 84 to 87 (RHR 1.14, 95% CI 0.87 to 1.48). Many variants of PSQ have been compared, although we did not see any strong and consistent messages from the results. Targeting multiple CpG sites is likely to be more prognostic than targeting just one. In addition, we identified and summarised 190 articles describing a single method for measuring MGMT promoter methylation status.

AUTHORS' CONCLUSIONS

PSQ and MSP appear more prognostic for overall survival than IHC. Strong evidence is not available to draw conclusions with confidence about the best CpG sites or thresholds for quantitative methods. MSP has been studied mainly for CpG sites 76 to 80 and 84 to 87 and PSQ at CpG sites ranging from 72 to 95. A threshold of 9% for CpG sites 74 to 78 performed better than higher thresholds of 28% or 29% in two of three good-quality studies making such comparisons.

Apatinib Plus Temozolomide: An Effective Salvage Treatment for Recurrent Glioblastoma

Background

Treatment for recurrent glioblastoma is poor, and there is a need for better therapies. Here we retrospectively assessed the efficacy and toxicity of temozolomide plus apatinib, an oral small-molecule tyrosine kinase inhibitor targeting vascular endothelial growth factor receptor 2 in recurrent glioblastoma.

Materials and Methods

A retrospective analysis of patients with recurrent glioblastoma who underwent apatinib plus temozolomide treatment was performed. Apatinib was given at 500 mg once daily. Temozolomide was administered at 200 mg/m²/d on days 1–5 or 50 mg/m²/d continuous daily according to whether they had experienced temozolomide maintenance treatment before. The main clinical data collected included tumor characteristics, status of MGMT promoter, and IDH mutation, number of relapse, response, survival, adverse reactions, and salvage therapies.

Results

From April 2016 to August 2019, thirty-one patients were identified. The objective response rate was 26.3%, and the disease control rate was 84.2%. The progression-free survival (PFS) at 6 months and overall survival (OS) at 12 months were 44.6 and 30.2%. The median PFS and OS were 4.9 and 8.2 months, respectively. Two patients achieved long PFS of 30.9 and 38.7+ months. The median survival time after progression of the patients with or without salvage bevacizumab was 5.1 versus 1.2 months. The most common grade 3 or 4 toxicities were hypertension (5.8%), decreased appetite (5.8%), and thrombocytopenia (4.3%), most of which were resolved after symptomatic treatment or dose reduction.

Conclusion

Apatinib plus temozolomide is an effective salvage regimen with manageable toxicities for recurrent glioblastoma and could not reduce the sensitivity to bevacizumab.

A neuro evolutionary algorithm for patient calibrated prediction of survival in Glioblastoma patients

BACKGROUND AND OBJECTIVES

Glioblastoma multiforme (GBM) is the most common and malignant type of primary brain tumors. Radiation therapy (RT) plus concomitant and adjuvant Temozolomide (TMZ) constitute standard treatment of GBM. Existing models for GBM growth do not consider the effect of different schedules on tumor growth and patient survival. However, clinical trials show that treatment schedule and drug dosage significantly affect patient survival. The goal is to provide a patient calibrated model for predicting survival according to the treatment schedule.

METHODS

We propose a top-down method based on artificial neural networks (ANN) and genetic algorithm (GA) to predict survival of GBM patients. A feed forward undercomplete Autoencoder network is integrated with the neuro-evolutionary (NE) algorithm in order to extract a compressed representation of input clinical data. The proposed NE algorithm uses GA to obtain optimal architecture of a multi-layer perceptron (MLP). Taguchi L₁₆ orthogonal design of experiments is used to tune parameters of the proposed NE algorithm. Finally, the optimal MLP is used to predict survival of GBM patients.

RESULTS

Data from 8 related clinical trials have been collected and integrated to train the model. From 847 evaluable cases, 719 were used for train and validation and the remaining 128 cases were used to test the model. Mean absolute error of the predictions on the test data is 0.087 months which shows excellent performance of the proposed model in predicting survival of the patients. Also, the results show that the proposed NE algorithm is superior to other existing models in both the mean and variability of the prediction error.

Bortezomib administered prior to temozolomide depletes MGMT, chemosensitizes glioblastoma with unmethylated MGMT promoter and prolongs animal survival

Background

Resistance to temozolomide (TMZ) is due in part to enhanced DNA repair mediated by high expression of O⁶-methyl guanine DNA methyltransferase (MGMT) that is often characterised by unmethylated promoter. Here, we investigated pre-treatment of glioblastoma (GBM) cells with the 26S-proteasome inhibitor bortezomib (BTZ) as a strategy to interfere with MGMT expression and thus sensitise them to TMZ.

Methods

Cell lines and patient GBM-derived cells were examined in vitro, and the latter also implanted orthotopically into NOD-SCID C.B.-Igh-1b/lcrTac-Prkdc mice to assess efficacy and tolerability of BTZ and TMZ combination therapy. MGMT promoter methylation was determined using pyrosequencing and PCR, protein signalling utilised western blotting while drug biodistribution was examined by LC-MS/MS. Statistical analysis utilised Analysis of variance and the Kaplan–Meier method.

Results

Pre-treatment with BTZ prior to temozolomide killed chemoresistant GBM cells with unmethylated MGMT promoter through MGMT mRNA and protein depletion in vitro without affecting methylation. Chymotryptic activity was abolished, processing of NFkB/p65 to activated forms was reduced and corresponded with low MGMT levels. BTZ crossed the blood–brain barrier, diminished proteasome activity and significantly prolonged animal survival.

Conclusion

BTZ chemosensitized resistant GBM cells, and the schedule may be amenable for temozolomide refractory patients with unmethylated MGMT promoter.

Evidence-Based Practice: Temozolomide Beyond Glioblastoma

PURPOSE OF REVIEW

Temozolomide is a first-line treatment for newly diagnosed glioblastoma. In this review, we will examine the use of temozolomide in other contexts for treating gliomas, including recurrent glioblastoma, glioblastoma in the elderly, diffuse low- and high-grade gliomas, non-diffuse gliomas, diffuse intrinsic pontine glioma (DIPG), ependymoma, pilocytic astrocytoma, and pleomorphic xanthoastrocytoma.

RECENT FINDINGS

Temozolomide improved survival in older patients with glioblastoma, anaplastic gliomas regardless of 1p/19q deletion status, and progressive ependymomas. Temozolomide afforded less toxicity and comparable efficacy to radiation in high-risk low-grade gliomas and to platinum-based chemotherapy in pediatric high-grade gliomas. The success of temozolomide in promoting survival has expanded beyond glioblastoma to benefit patients with non-glioblastoma tumors. Identifying practical biomarkers for predicting temozolomide susceptibility, and establishing complementary agents for chemosensitizing tumors to temozolomide, will be key next steps for future success.

Looking for A Place for Dose-Dense TMZ Regimens in GBM Patients: An Experience with MGMT Exploratory Evaluation

Prolonged exposure to temozolomide (TMZ) could improve clinical outcomes in recurrent glioblastoma multiforme (GBM) patients. We previously developed a dose-dense regimen of TMZ in a phase II study (180 mg/m² from days 1 to 5 every two weeks). A retrospective analysis of patients with macroscopic residual GBM treated with “post-induction” dose-dense TMZ was conducted, adding an explorative subgroup analyses among patients with different O⁶-methylguanine DNA methyltransferase (MGMT) expressions (negative vs positive, < vs ≥ of 50 % of cells stained, < vs ≥ 70% of cells stained). Thirty-six patients were evaluated; after a median follow-up of 36 weeks, median Progression Free Survival (PFS) and median Overall Survival (OS) were 19 and 34 weeks, respectively. MGMT expression (70% cut-off) and sex were confirmed as independent predictors for disease control rate (DCR) at multivariate analysis. At univariate analysis ECOG-PS, Sex (female), extensive tumor resection was shown to be related to a longer PFS, while MGMT expression (cut-off 70%) to a shorter PFS. Multivariate analysis with Cox hazard regression confirmed only ECOG-PS as an independent predictor for PFS. ECOG-PS showed to be significant related to a longer OS. Our analysis showed that dose-dense TMZ regimens are still an option for patients with recurrent GBM, but should be used for re-challenge treatments. MGMT immunohistochemistry high expression might be used as a “surrogate” negative predictor for DCR for dd-TMZ treatments.

Boron Neutron Capture Therapy Combined with Early Successive Bevacizumab Treatments for Recurrent Malignant Gliomas - A Pilot Study

Recurrent malignant gliomas (RMGs) are difficult to control, and no standard protocol has been established for their treatment. At our institute, we have often treated RMGs by tumor-selective particle radiation called boron neutron capture therapy (BNCT). However, despite the cell-selectivity of BNCT, brain radiation necrosis (BRN) may develop and cause severe neurological complications and sometimes death. This is partly due to the full-dose X-ray treatments usually given earlier in the treatment course. To overcome BRN following BNCT, recent studies have used bevacizumab (BV). We herein used extended BV treatment beginning just after BNCT to confer protection against or ameliorate BRN, and evaluated; the feasibility, efficacy, and BRN control of this combination treatment. Seven patients with RMGs (grade 3 and 4 cases) were treated with BNCT between June 2013 and May 2014, followed by successive BV treatments. They were followed-up to December 2017. Median overall survival (OS) and progression-free survival (PFS) after combination treatment were 15.1 and 5.4 months, respectively. In one case, uncontrollable brain edema occurred and ultimately led to death after BV was interrupted due to meningitis. In two other cases, symptomatic aggravation of BRN occurred after interruption of BV treatment. No BRN was observed during the observation period in the other cases. Common terminology criteria for adverse events grade 2 and 3 proteinuria occurred in two cases and necessitated the interruption of BV treatments. Boron neutron capture therapy followed by BV treatments well-prevented or well-controlled BRN with prolonged OS and acceptable incidence of adverse events in our patients with RMG.

Phase 1 lead-in to a phase 2 factorial study of temozolomide plus memantine, mefloquine, and metformin as postradiation adjuvant therapy for newly diagnosed glioblastoma

BACKGROUND

Repurposed memantine, mefloquine, and metformin have putative anticancer activity. The objective of this phase 1 study was to determine the maximum tolerated doses (MTDs) of combinations of these agents with temozolomide (TMZ).

METHODS

Adults with newly diagnosed glioblastoma who completed chemoradiation were eligible. The patients were assigned to receive doublet, triplet, or quadruplet therapy with TMZ combined with mefloquine, memantine, and/or metformin. Dose-limiting toxicities (DLTs) were determined, using a 3 + 3 study design.

RESULTS

Of 85 enrolled patients, 4 did not complete cycle 1 (the DLT observation period) for nontoxicity reasons, and 81 were evaluable for DLT. The MTDs for doublet therapy were memantine 20 mg twice daily, mefloquine 250 mg 3 times weekly, and metformin 850 mg twice daily. For triplet therapy, the MTDs were memantine 10 mg twice daily, mefloquine 250 mg 3 times weekly, and metformin 850 mg twice daily. For quadruplet therapy, the MTDs were memantine 10 mg twice daily, mefloquine 250 mg 3 times weekly, and metformin 500 mg twice daily. DLTs included dizziness (memantine) and gastrointestinal effects (metformin). Lymphopenia was the most common adverse event (66%). From study entry, the median survival was 21 months, and the 2-year survival rate was 43%.

CONCLUSIONS

Memantine, mefloquine, and metformin can be combined safely with TMZ in patients with newly diagnosed glioblastoma.

Dose-dense temozolomide for recurrent high-grade gliomas: a single-center retrospective study

There are limited treatment modalities after high-grade gliomas recurrence. MGMT depletion modulated by dose-dense temozolomide (ddTMZ) remains a debated therapy for initial TMZ responders. Patients were selected retrospectively from our practice with diagnosis of high-grade gliomas (WHO grade III or IV), and were followed since the start of ddTMZ until death or change of therapy. Twenty-one patients were reviewed, with a median age of 47 (25-61) years and a median of 5.8 (1.5-38.8) cycles of ddTMZ. The majority were males (71.4%). Sixty-six percent received 21 on/28 off ddTMZ schedule, 28.6% daily, and 1 patient received a 7 days on/7 days off schedule. IDH mutation status was available for 18 (85.7%) patients, with 7 (33.3%) IDH mutant and 11 (52.5%) IDH wild type. MGMT methylation was assessed in 6 (28.6%) of the patients, being MGMT methylated in 3 (14.3%) patients, and non-methylated in 3 (14.3%) patients. The majority of patients (57.1%) were receiving ddTMZ in addition to other forms of therapy, including either bevacizumab (38.1%) or tumor-treating fields (TTFields) (19.1%). Overall ddTMZ was well tolerated, with few adverse events reported. The estimated median overall survival after ddTMZ start was 11 months. Median progression-free survival (PFS) was 6 months. Outcomes did not vary between patients receiving ddTMZ alone or those using TTFields or bevacizumab as concomitant therapy, but there was a trend to longer survival with the use of concomitant TTFields. Our results demonstrate benefit of ddTMZ after previous treatment with standard TMZ dosing with no apparent increase in treatment-related toxicities. In summary, ddTMZ should be considered in TMZ responsive patients and warrants further investigation.

Retrospective study of nivolumab for patients with recurrent high grade gliomas

INTRODUCTION

Patients with recurrent high-grade gliomas (HGG) have limited treatment options. HGG utilize the PD-1 pathway to evade immune responses. Checkpoint inhibitors have demonstrated safety and clinical activity in patients with recurrent glioblastoma. We explored the efficacy of nivolumab in recurrent HGG with a primary objective of progression free survival (PFS) and overall survival (OS).

METHODS

We retrospectively analyzed HGG patients treated with nivolumab in our institution. We included patients with advanced HGG who received nivolumab at their oncologist's decision. Patients received nivolumab 3 mg/kg every 2 weeks until confirmed progression, intolerable toxicity, death, or physician decision. Radiographic assessments were performed every 8 weeks.

RESULTS

Between April 2015 and October 2017, 50 HGG patients received nivolumab. 43 patients received nivolumab with bevacizumab. 44 patients were bevacizumab refractory and 7 patients received nivolumab monotherapy. All had received prior radiation and chemotherapy. 39 adverse events (AEs) were noted [most commonly fatigue (16%) and constipation (10%)]. 4 (8%) patients experienced grade 3-4 AEs. 36 (72%) patients experienced stable disease (SD) at the 2-month assessment. Median duration of SD was 4.3 months (5.1 months in the bevacizumab naïve, 3.8 months in the bevacizumab refractory). Median PFS was 4.3 months (95% CI 3.5-5.3); median OS was 6.5 months (95% CI 6.0-8.8).

CONCLUSION

Treatment with nivolumab therapy was associated with a manageable safety profile. In a subset of patients, there was disease stabilization in heavily pre-treated recurrent HGG.

Analyses of repeated failures in cancer therapy for solid tumors: poor tumor-selective drug delivery, low therapeutic efficacy and unsustainable costs

For over six decades reductionist approaches to cancer chemotherapies including recent immunotherapy for solid tumors produced outcome failure-rates of 90% (±5) according to governmental agencies and industry. Despite tremendous public and private funding and initial enthusiasm about missile-therapy for site-specific cancers, molecular targeting drugs for specific enzymes such as kinases or inhibitors of growth factor receptors, the outcomes are very bleak and disappointing. Major scientific reasons for repeated failures of such therapeutic approaches are attributed to reductionist approaches to research and infinite numbers of genetic mutations in chaotic molecular environment of solid tumors that are bases of drug development. Safety and efficacy of candidate drugs tested in test tubes or experimental tumor models of rats or mice are usually evaluated and approved by FDA. Cost-benefit ratios of such 'targeted' therapies are also far from ideal as compared with antibiotics half a century ago. Such alarming records of failure of clinical outcomes, the increased publicity for specific vaccines (e.g., HPV or flu) targeting young and old populations, along with increasing rise of cancer incidence and death created huge and unsustainable cost to the public around the globe. This article discusses a closer scientific assessment of current cancer therapeutics and vaccines. We also present future logical approaches to cancer research and therapy and vaccines.

Management and treatment recommendations for World Health Organization Grade III and IV gliomas

The treatment recommendations provided in this manuscript are intended to serve as a knowledge base for clinicians and health personals involved in treating patients with high-grade malignant glioma. In newly diagnosed patients, complete resection or biopsy is required for histological characterization of the tumor, which in turn is essential to decide the treatment strategy. In patients with good or borderline performance score, radiotherapy (RT), and chemotherapy are the preferred management. In patients with poor performance score, RT with best possible supportive care is the mainstay of the management. All patients have to undergo brain magnetic resonance imaging procedure quarterly or half-yearly for 5 years and then on an annual basis. In patients with recurrent malignant glioma, wherever possible re-resection or re-irradiation or chemotherapy can be considered along with supportive and palliative care. High-grade malignant glioma should be managed in a multidisciplinary center with the best of the possible care that is available based on the evidence as discussed in this manuscript.

Prolonged survival in patients with breast cancer and a history of brain metastases: results of a preplanned subgroup analysis from the randomized phase III BEACON trial

Purpose

Conventional chemotherapy has limited activity in patients with breast cancer and brain metastases (BCBM). Etirinotecan pegol (EP), a novel long-acting topoisomerase-1 inhibitor, was designed using advanced polymer technology to preferentially accumulate in tumor tissue including brain metastases, providing sustained cytotoxic SN38 levels.

Methods

The phase 3 BEACON trial enrolled 852 women with heavily pretreated locally recurrent or metastatic breast cancer between 2011 and 2013. BEACON compared EP with treatment of physician’s choice (TPC; eribulin, vinorelbine, gemcitabine, nab-paclitaxel, paclitaxel, ixabepilone, or docetaxel) in patients previously treated with anthracycline, taxane, and capecitabine, including those with treated, stable brain metastases. The primary endpoint, overall survival (OS), was assessed in a pre-defined subgroup of BCBM patients; an exploratory post hoc analysis adjusting for the diagnosis-specific graded prognostic assessment (GPA) index was also conducted.

Results

In the trial, 67 BCBM patients were randomized (EP, n = 36; TPC, n = 31). Treatment subgroups were balanced for baseline characteristics and GPA indices. EP was associated with a significant reduction in the risk of death (HR 0.51; P < 0.01) versus TPC; median OS was 10.0 and 4.8 months, respectively. Improvement in OS was observed in both poorer and better GPA prognostic groups. Survival rates at 12 months were 44.4% for EP versus 19.4% for TPC. Consistent with the overall BEACON population, fewer patients on EP experienced grade ≥3 toxicity (50 vs. 70%).

Conclusions

The significant improvement in survival in BCBM patients provides encouraging data for EP in this difficult-to-treat subgroup of patients. A phase three trial of EP in BCBM patients is underway (ClinicalTrials.gov NCT02915744).

Electronic supplementary material

The online version of this article (doi:10.1007/s10549-017-4304-7) contains supplementary material, which is available to authorized users.

Nivolumab for patients with recurrent glioblastoma progressing on bevacizumab: a retrospective case series

A single institution retrospective evaluation of nivolumab following disease progression on bevacizumab in adults with recurrent glioblastoma (GBM) with an objective of determining progression free survival (PFS). There is no accepted therapy for recurrent GBM after failure of bevacizumab. 16 adults, ages 52-72 years (median 62), with recurrent GBM were treated. All patients had previously been treated with surgery, concurrent radiotherapy and temozolomide, and post-radiotherapy temozolomide. Bevacizumab (with or without lomustine) was administered to all patients at first recurrence. Patients were treated with nivolumab only (3 mg/kg) once every 2 weeks at second recurrence. One cycle of nivolumab was defined as 2 treatments. Neurological evaluation was performed bi-weekly and neuroradiographic assessment every 4 weeks. A total of 37 treatment cycles (median 2) were administered of nivolumab in which there were 14 Grade 2 adverse events (AEs) and Grade 3 AEs in two patients. No Grade 4 or 5 AEs were seen. Following 1 month of nivolumab, seven patients demonstrated progressive disease and discontinued therapy. No patient demonstrated a response though nine patients demonstrated neuroradiographic stable response. Survival in the entire cohort ranged from 2 to 6 months with a median of 3.5 months (CI 2.8, 4.2). Median and 6-month PFS at 6 months was 2.0 months (range 1-5 months; CI 1.3, 2.7) and 0% respectively. Nivolumab salvage therapy demonstrated no survival advantage in patients with recurrent bevacizumab refractory GBM emphasizing a continued unmet need in neuro-oncology.

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.

Treatment options for recurrent high-grade gliomas

High-grade gliomas are aggressive brain tumors encompassing Grade III and IV classifications. Of these, glioblastoma (GB) is the most malignant with a high rate of recurrence after initial resection. Although standard treatment does exist for newly diagnosed GBs, therapeutic strategies for recurrent GB are less solidified. However, mounting evidence describes the role of re-resection, bevacizumab, chemotherapy, targeted molecular therapies, immunotherapeutic approaches and radiotherapy in recurrent GB management. This review article provides analysis of the aforementioned therapies, through assessing their effect on overall survival. Because GB tumor heterogeneity is prevalent there is a constant need to investigate therapies targeting recurrence. Studies evaluating both therapeutic targets and strategies for high-grade gliomas are and will remain invaluable.

Management of glioblastoma after recurrence: A changing paradigm

Glioblastoma remains the most common primary brain tumor after the age of 40years. Maximal safe surgery followed by adjuvant chemoradiotherapy has remained the standard treatment for glioblastoma (GBM). But recurrence is an inevitable event in the natural history of GBM with most patients experiencing it after 6-9months of primary treatment. Recurrent GBM poses great challenge to manage with no well-defined management protocols. The challenge starts from differentiating radiation necrosis from true local progression. A fine balance needs to be maintained on improving survival and assuring a better quality of life. Treatment options are limited and ranges from re-excision, re-irradiation, systemic chemotherapy or a combination of these. Re-excision and re-irradiation must be attempted in selected patients and has been shown to improve survival outcomes. To facilitate the management of GBM recurrences, a treatment algorithm is proposed.

Phase II trial of irinotecan and metronomic temozolomide in patients with recurrent glioblastoma

This phase II study was conducted to determine the efficacy and safety of metronomic temozolomide (TMZ) in combination with irinotecan in glioblastoma (GB) at first relapse. Patients with GB at first relapse received TMZ 50 mg/m/2day divided into three doses, except for a single 100 mg/m2 dose, administered between 3 and 6 h before every irinotecan infusion. Irinotecan was given intravenously at the previously established dose of 100 mg/m2 on days 8 and 22 of 28-day cycles. Treatment was given for a maximum of nine cycles or until progression or unacceptable toxicity occurred. Vascular endothelial growth factor and its soluble receptor 1, thrombospondin-1, microparticles, and microparticle-dependent procoagulant activity were measured in blood before treatment. The primary objective was 6-month progression-free survival (PFS). Twenty-seven evaluable patients were enrolled. Six-month PFS was 20.8%. Median PFS was 11.6 weeks (95% confidence interval: 7.5-15.7). Stable disease was the best response for nine (37.5%) patients, with a median duration of 11.2 weeks (4.2-35.85 weeks). No differences in PFS or response were observed among patients who relapsed during or after completion of adjuvant TMZ. Grade 3/4 adverse events included lymphopenia (15%), fatigue, diarrhea and febrile neutropenia (3.7% each), lymphopenia, neutropenia, and nausea/vomiting (11.1% each). One patient died from pneumonia and one patient died from pulmonary thromboembolism. Pretreatment levels of angiogenesis biomarkers, microparticles, and microparticle-related procoagulant activity were elevated in patients compared with healthy volunteers. This regimen is feasible, but failed to improve the results obtained with other second-line therapies in recurrent GB.

Metastatic Gastrointestinal Stromal Tumor to the Skull

BACKGROUND

Gastrointestinal stromal tumors (GISTs) arising from the interstitial cells of Cajal along the gastrointestinal tract rarely metastasize to the central nervous system (CNS) but require aggressive multimodal therapies when they do. We present a case of recurrent GIST metastasis to the skull and review the literature on management, including the role of molecular profiling in determining adjuvant treatment.

CASE

A 64-year-old woman presented with an enlarging palpable mass over her right eye. Magnetic resonance imaging revealed an enhancing T1-hypointense, T2-hyperintense right frontal calvarial lesion with lytic features on computed tomography. Pathology confirmed metastatic GIST to the skull with dural involvement. Molecular profiling revealed a mutation in exon 11 of KIT in her primary tumor, while the skull metastasis harbored an additional mutation in exon 17 associated with acquired drug resistance.

CONCLUSION

We review the epidemiology of GIST metastases and discuss potential reasons for its rare presentation to the CNS. Additionally, we highlight the diagnostic and prognostic value of molecular profiling for metastatic GIST, as well as its influence in arbitrating targeted molecular inhibitor therapy. Evolving molecular signatures, associated with treatment resistance, may play a pivotal role in future integration with multimodality treatment strategies for CNS GIST.

Therapeutic options in recurrent glioblastoma--An update

INTRODUCTION

Standards of care are not yet defined in recurrent glioblastoma.

METHODS

We reviewed the literature on clinical trials for recurrent glioblastoma available in PubMed and American Society of Clinical Oncology (ASCO) abstracts until June 2015.

RESULTS

Evidence is limited due to the paucity of randomized controlled studies. Second surgery or re-irradiation are options for selected patients. Alkylating chemotherapy such as nitrosoureas or temozolomide and the vascular endothelial growth factor (VEGF) antibody, bevacizumab, exhibit comparable single agent activity. Phase III data exploring the benefit of combining bevacizumab and lomustine are emerging. Novel approaches in the fields of targeted therapy, immunotherapy, and tumor metabolism are coming forward. Several biomarkers are being explored, but, except for O(6)-methylguanine DNA methyltransferase (MGMT) promoter methylation, none has assumed a role in clinical practice.

CONCLUSION

Proper patient selection, development of predictive biomarkers and randomized controlled studies are required to develop evidence-based concepts for recurrent glioblastoma.

A prospective, multicentre, single-arm clinical trial of bevacizumab for patients with surgically untreatable, symptomatic brain radiation necrosis†

Background

Brain radiation necrosis (BRN) can be a complication of radiotherapy for primary and secondary brain tumors, as well as head and neck tumors. Since vascular endothelial growth factor (VEGF) is also a vascular permeability factor in the brain, bevacizumab, a humanized antibody that inhibits VEGF, would be expected to reduce perilesional edema that often accompanies BRN.

Methods

Patients with surgically untreatable, symptomatic BRN refractory to conventional medical treatments (eg, corticosteroid, anticoagulants, or hyperbaric oxygen therapy) were enrolled. We judged that a major cause of perilesional edema with a lesion-to-normal brain ratio ≤1.8 on ¹¹C-methionine or ≤2.5 on ¹⁸F-boronophenylalanine PET was BRN, not tumor recurrence, and 6 cycles of biweekly bevacizumab (5 mg/kg) were administered. The primary endpoint was a ≥30% reduction from the patients' registration for perilesional edema continuing for ≥1 month.

Results

Of the 41 patients enrolled, 38 were fully eligible for the response assessment. The primary endpoint was achieved in 30 of the 38 (78.9%) patients at 3.0 months (median) after enrollment. Sixteen patients (42.1%) experienced improvement of their Karnofsy Performance Score. Corticosteroid use could be reduced in 29 patients (76.3%). Adverse events at grade ≥3 occurred in 10 patients (24.4%).

Conclusions

Bevacizumab treatment offers certain clinical benefits for patients with surgically untreatable, symptomatic BRN. The determination of BRN using amino-acid PET, not biopsy, is adequate and less invasive for determining eligibility to receive bevacizumab.

Survival following reirradiation using intensity-modulated radiation therapy with temozolomide in selected patients with recurrent high grade gliomas

BACKGROUND

High grade gliomas often recur after initial treatment. Despite so many treatment options, there is no standard treatment for recurrent gliomas. The aim of this study is to offer survival following reirradiation (re-RT) using intensity-modulated radiation therapy (IMRT) with temozolomide in selected patients with recurrent high grade gliomas.

METHODS

We examined the medical records of 21 adult patients with recurrent high grade gliomas who were reirradiated with IMRT at the time of tumor recurrence or progression. Tumor recurrence was shown by gadolinium-enhanced magnetic resonance imaging (MRI) and diagnosis was established by pathology review. Statistical analyses were performed with SPSS version 18.0.1 using Cox regression analyses, log-rank test and Kaplan-Meier method.

RESULTS

Eighteen patients presented by localized recurrence, three patients with diffuse recurrence. Median radiotherapy (RT) dose was 54 Gy. About 81% patients received temozolomide with re-RT. The time interval between two courses RT was median 39.3 months (range, 9.6-140.8 months). The response was checked by MRI. About 24% patients achieved complete response (CR) and 29% patient partial response (PR). Stable disease (SD) was observed in 47% patients. Median follow-up time from diagnosis was 41.4 months (range, 16.6-145.4 months) and 12.3 months (range, 2-27.6 months) from re-RT. Median time to recurrence was 39.3 months (range, 9.6-140.8 months). Median survival after re-RT was 18 months for anaplastic astrocytoma (AA), 14.1 months for glioblastoma multiforme (GBM) (range, 11-17.2 months) (P=0.1) and 7.1 months for patients with Karnofsky performance status (KPS) <70 before re-RT and 17.4 months for KPS >70 (P=0.02).

CONCLUSIONS

re-RT is one of the treatment options for recurrent high grade gliomas and IMRT can be an effective treatment modality for recurrent high grade brain tumors with only mild side effects. Survival is better in patients with good performance status and in recurrent anaplastic tumors after re-RT.

Continuous Low-Dose Temozolomide Chemotherapy and Microvessel Density in Recurrent Glioblastoma

Objective

The purpose of this study was to evaluate the clinical efficacy of continuous low-dose temozolomide (TMZ) chemotherapy for recurrent and TMZ-refractory glioblastoma multiforme (GBM) and to study the relationship between its efficacy and microvessel density within the tumor.

Methods

Thirty patients who had recurrent GBM following Stupp's regimen received TMZ daily at 50 mg/m²/day until tumor progression between 2007 and 2013. The median duration of continuous low-dose TMZ administration was 8 weeks (range, 2-64).

Results

The median progression-free survival (PFS) of continuous low-dose TMZ therapy was 2 months (range, 0.5-16). At 6 months, PFS was 20%. The median overall survival (OS) from the start of this therapy to death was 6 months (95% CI : 5.1-6.9). Microvessel density of recurrent tumor tissues obtained by reoperation of 17 patients was 22.7±24.1/mm² (mean±standard deviation), and this was lower than that of the initial tumor (61.4±32.7/mm²) (p-value=0.001). It suggests that standard TMZ-chemoradiotherapy reduces the microvessel density within GBM and that recurrences develop in tumor cells with low metabolic burden. The efficacy of continuous low-dose TMZ could not be expected in recurrent GBM cells in poor angiogenic environments.

Conclusion

The efficacy of continuous low-dose TMZ chemotherapy is marginal. This study suggests the need to develop further treatment strategies for recurrent and TMZ-refractory GBM.

The efficacy and safety of various dose-dense regimens of temozolomide for recurrent high-grade glioma: a systematic review with meta-analysis

The goal of this meta-analysis was to identify the temozolomide (TMZ) regimen with optimal efficacy and tolerance for treatment of recurrent high-grade glioma (HGG). The PubMed and EMBASE databases were searched from the earliest records to February 2015, which identified 33 studies with 1760 participants that met the inclusion criteria. The standard schedule and three most common dose-dense regimens of TMZ therapy for recurrent HGG were included in this meta-analysis. The schedule of 7 days on/7 days off for the treatment of grade IV gliomas was significantly superior to the standard regimen with respect to progression-free survival at 6 months (34.8 %; 95 % confidence interval (CI) 27.0-43.4 %) and 12 months (15.5 %; 95 % CI 10.7-21.8 %). For grade III gliomas, this regimen conveyed a significantly greater overall survival (OS) rate at 12 months (79.0 %; 95 % CI 56.2-91.7 %), as compared to the standard schedule. Also, the 21 days on/7 days off regimen had significantly longer OS rates at 6 months (73.6 %; 95 % CI 63.4-81.8 %) and 12 months (40.6 %; 95 % CI 32.6-48.6 %) than the standard regimen for grade IV gliomas. In addition, the standard schedule showed a significantly higher clinical benefit rate than the 7 days on/7 days off and 21 days on/7 days off regimens. However, the grade 3-4 toxicity rate of lymphopenia of the standard schedule was 76.5 % (95 % CI 45.5-92.7 %), which was the highest among the four regimens. Recurrent HGG patients receiving personalized treatment should be closely followed up, especially those with concurrent hematological diseases.

Phase II pilot study of single-agent etirinotecan pegol (NKTR-102) in bevacizumab-resistant high grade glioma

Patients with recurrence of high-grade glioma (HGG) after bevacizumab (BEV) have an extremely poor prognosis. Etirinotecan pegol (EP) is the first long-acting topoisomerase-I inhibitor designed to concentrate in and provide continuous tumor exposure throughout the entire chemotherapy cycle. Here we report results of a Phase 2, single arm, open-label trial evaluating EP in HGG patients who progressed after BEV. Patients age >18 with histologically proven anaplastic astrocytoma or glioblastoma (GB) who previously received standard chemo-radiation and recurred after BEV were eligible. A predicted life expectancy >6 weeks and KPS ≥ 50 were required. The primary endpoint was PFS at 6-weeks. Secondary endpoint was overall survival from first EP infusion. Response was assessed by RANO criteria. Single agent EP was administered IV every 3 weeks at 145 mg/m2. Patients did not receive BEV while on EP. 20 patients (90 % GB) were enrolled with a median age of 50 and median KPS of 70. Three patients with GB (16.7 % of GB) had partial MRI responses. 6-week PFS was 55 %. Median and 6-month PFS were 2.2 months (95 % CI 1.4–3.4 months) and 11.2 % (95 % CI 1.9–28.9 %) respectively. Median overall survival from first EP infusion was 4.5 months (95 % CI 2.4–5.9). Only one patient had grade 3 toxicity (diarrhea with dehydration) attributable to EP. Hematologic toxicity was mild. Three patients had confirmed partial responses according to RANO criteria. These clinical data combined with a favorable safety profile warrant further clinical investigation of this agent in HGG.

Chemotherapy in glioma

The treatment of glial brain tumors begins with surgery, and standard adjuvant treatment at the end of the past millennium for high-grade glioma and high-risk low-grade glioma was radiotherapy and chemotherapy was given at recurrence. However, over the past 10 years much has changed regarding the role of chemotherapy in gliomas and it is now clear that chemotherapy has a role in the treatment of almost all newly diagnosed diffuse gliomas (WHO grade II-IV). This is the result of several prospective studies that showed survival benefit after combined chemoradiotherapy with temozolomide in glioblastoma (WHO grade IV) or after procarbazine, CCNU (lomustine) and vincristine chemotherapy in diffuse low-grade (WHO grade II) and anaplastic (WHO grade III) glioma. The current standard of treatment for diffuse gliomas is described in this overview and in addition some attention is given to targeted therapies.

Predictive value of MGMT promoter methylation status in Asian and Caucasian patients with malignant gliomas: a meta-analysis

BACKGROUND

The prognostic significance of O6-methylguanine-DNA methyltransferase (MGMT) promoter status for survival of patients with malignant gliomas remains controversial. Thus, the meta-analysis was performed in order to identify the impact of MGMT expression on prognosis of malignant gliomas.

METHOD

An extensive literature search for relevant studies was conducted on PubMed, Embase, Web of Science, Cochrane Library, and CBM databases. Version 12.0 STATA software was used for the current meta-analysis. Hazard ratios (HRs) with their corresponding 95% confidence interval (95% CI) were also calculated to clarify the correlation between MGMT expression and the prognosis of malignant gliomas.

RESULTS

Final analysis of 2,377 malignant gliomas patients from 32 clinical studies was performed. The meta-analysis results show that MGMT promoter group and unmethylated MGMT group has a significant difference (all P < 0.01). Combined HR of MGMT suggests that the methylated MGMT group has a longer overall survival than the unmethylated MGMT group (P < 0.01), but the Asians don't present a difference between the two groups.

CONCLUSION

The meta-analysis study shows that the elevated MGMT promoter group may have a better prognosis in malignant gliomas patients, but the Asians don't have a better prognosis.

The future of high-grade glioma: Where we are and where are we going

High-grade glioma (HGG) are optimally treated with maximum safe surgery, followed by radiotherapy (RT) and/or systemic chemotherapy (CT). Recently, the treatment of newly diagnosed anaplastic glioma (AG) has changed, particularly in patients with 1p19q codeleted tumors. Results of trials currenlty ongoing are likely to determine the best standard of care for patients with noncodeleted AG tumors. Trials in AG illustrate the importance of molecular characterization, which are germane to both prognosis and treatment. In contrast, efforts to improve the current standard of care of newly diagnosed glioblastoma (GB) with, for example, the addition of bevacizumab (BEV), have been largely disappointing and furthermore molecular characterization has not changed therapy except in elderly patients. Novel approaches, such as vaccine-based immunotherapy, for newly diagnosed GB are currently being pursued in multiple clinical trials. Recurrent disease, an event inevitable in nearly all patients with HGG, continues to be a challenge. Both recurrent GB and AG are managed in similar manner and when feasible re-resection is often suggested notwithstanding limited data to suggest benefit from repeat surgery. Occassional patients may be candidates for re-irradiation but again there is a paucity of data to commend this therapy and only a minority of selected patients are eligible for this approach. Consequently systemic therapy continues to be the most often utilized treatment in recurrent HGG. Choice of therapy, however, varies and revolves around re-challenge with temozolomide (TMZ), use of a nitrosourea (most often lomustine; CCNU) or BEV, the most frequently used angiogenic inhibitor. Nevertheless, no clear standard recommendation regarding the prefered agent or combination of agents is avaliable. Prognosis after progression of a HGG remains poor, with an unmet need to improve therapy.

MGMT Promoter Methylation Is a Strong Prognostic Biomarker for Benefit from Dose-Intensified Temozolomide Rechallenge in Progressive Glioblastoma: The DIRECTOR Trial

PURPOSE

Rechallenge with temozolomide (TMZ) at first progression of glioblastoma after temozolomide chemoradiotherapy (TMZ/RT→TMZ) has been studied in retrospective and single-arm prospective studies, applying temozolomide continuously or using 7/14 or 21/28 days schedules. The DIRECTOR trial sought to show superiority of the 7/14 regimen.

EXPERIMENTAL DESIGN

Patients with glioblastoma at first progression after TMZ/RT→TMZ and at least two maintenance temozolomide cycles were randomized to Arm A [one week on (120 mg/m(2) per day)/one week off] or Arm B [3 weeks on (80 mg/m(2) per day)/one week off]. The primary endpoint was median time-to-treatment failure (TTF) defined as progression, premature temozolomide discontinuation for toxicity, or death from any cause. O(6)-methylguanine DNA methyltransferase (MGMT) promoter methylation was prospectively assessed by methylation-specific PCR.

RESULTS

Because of withdrawal of support, the trial was prematurely closed to accrual after 105 patients. There was a similar outcome in both arms for median TTF [A: 1.8 months; 95% confidence intervals (CI), 1.8-3.2 vs. B: 2.0 months; 95% CI, 1.8-3.5] and overall survival [A: 9.8 months (95% CI, 6.7-13.0) vs. B: 10.6 months (95% CI, 8.1-11.6)]. Median TTF in patients with MGMT-methylated tumors was 3.2 months (95% CI, 1.8-7.4) versus 1.8 months (95% CI, 1.8-2) in MGMT-unmethylated glioblastoma. Progression-free survival rates at 6 months (PFS-6) were 39.7% with versus 6.9% without MGMT promoter methylation.

CONCLUSIONS

Temozolomide rechallenge is a treatment option for MGMT promoter-methylated recurrent glioblastoma. Alternative strategies need to be considered for patients with progressive glioblastoma without MGMT promoter methylation.

Dose-dense temozolomide: is it still promising?

Glioblastoma (GBM) has proven to be incurable despite recent progress on its standard of care using temozolomide (TMZ) as the main trunk of initial therapy for newly diagnosed GBM. One of the main reasons accounting for the dismal prognosis is attributed to lack of active therapeutic regimens at recurrence. Since TMZ is the most active cytotoxic agent against GBM, and the standard dosing of TMZ has shown favorable safety profile in clinical trials, re-challenge with TMZ in increased dose density schedules for recurrent tumors that have evaded from prior standard TMZ therapy appears to be a rational approach and has been intensively exploited. A number of phase II clinical trials using different alternating scheduling of dose-dense TMZ (ddTMZ) have shown superior efficacy over the standard TMZ or historical controls with other alkylating agents including nitrosoureas and procarbazine. One ddTMZ schedule, consisting of a 21-days on/7-days off regimen was applied to newly-diagnosed GBM as the adjuvant monotherapy after completion of combined radiation and TMZ and failed to demonstrate survival benefit in a large phase III trial (RTOG 0525). Thus its role in TMZ-pretreated, recurrent GBM should be carefully pursuit in randomized trials, e.g., planned JCOG 1308 trial comparing a 7-days on/7-days off ddTMZ regimen used upfront at the first relapse followed by bevacizumab on progression versus bevacizumab alone, investigating whether insertion of ddTMZ prior to bevacizumab could bestow better outcome in the recurrent setting. In this article, mode of action, past trials, and future directions of ddTMZ therapy are discussed.