Bevacizumab plus hypofractionated radiotherapy versus radiotherapy alone in elderly patients with glioblastoma: the randomized, open-label, phase II ARTE trial

Advancements in targeted and immunotherapy strategies for glioma: toward precision treatment

In recent years, significant breakthroughs have been made in cancer therapy, particularly with the development of molecular targeted therapies and immunotherapies, owing to advances in tumor molecular biology and molecular immunology. High-grade gliomas (HGGs), characterized by their high malignancy, remain challenging to treat despite standard treatment regimens, including surgery, radiotherapy, chemotherapy, and tumor treating fields (TTF). These therapies provide limited efficacy, highlighting the need for novel treatment strategies. Molecular targeted therapies and immunotherapy have emerged as promising avenues for improving treatment outcomes in high-grade gliomas. This review explores the current status and recent advancements in targeted and immunotherapeutic approaches for high-grade gliomas.

Angiogenesis inhibitors effects on overall survival and progression-free survival in newly diagnosed primary glioblastoma multiforme: a meta-analysis of twelve randomized clinical trials

BACKGROUND

Glioblastoma multiforme (GBM) is the most common malignant brain tumor in adults. Typically treated with initial surgical resection, and chemoradiotherapy, despite current treatments, patients typically survive only 12-14 months, necessitating new therapeutic approaches. Our meta-analysis evaluates combining antiangiogenic medications with chemoradiotherapy versus using chemoradiotherapy alone in treating newly diagnosed GBM.

METHODS

A comprehensive literature search was conducted using PubMed/MEDLINE, Scopus, Cochrane and the Web of Science databases. The search aimed to identify studies reporting overall survival (OS), progression-free survival (PFS), and hazard ratio (HR) with corresponding confidence intervals (CIs) in patients with newly diagnosed GBM. We employed random-effect meta-analysis.

RESULTS

Twelve randomized clinical trials (RCTs) involved 3,309 patients included in the study. The findings showed that angiogenesis inhibitors significantly prolonged PFS [HR 0.85, 95% CI (0.73, 0.99), p-value = 0.04], while there was no significant difference on OS [HR 1.014, 95%CI (0.89, 1.15), p-value = 0.84]. Bevacizumab (BEV) exhibited the highest [HR 0.67, 95% CI (0.56, 0.79), p-value < 0.0001] and thalidomide exhibited the lowest [HR 1.46, 95% CI (1.004, 2.1), p-value = 0.048] improvements of PFS. Meta-regression revealed that age, white race, study sample size, infection, vascular disease complications, KPS > 60, biopsy, gross and subtotal resection can significantly influenced the PFS, while only the year of publication affected OS.

CONCLUSIONS

The current study showed that improve the PFS with no significant effect on OS. Our findings may provide some evidence for decision-making regarding the utilization of angiogenesis inhibitors for the treatment of adult patients with newly diagnosed GBM.

A Systematic Review and Meta-Analysis on the Effectiveness of Radiotherapy and Temozolomide Treatment With or Without Bevacizumab in Patients With Glioblastoma Multiforme

Glioblastoma multiforme (GBM) is the most frequent primary brain malignancy in adults. Despite improvements in imaging and therapy, the prognosis remains poor. To evaluate and compare the impact of combining bevacizumab with temozolomide and radiotherapy on progression-free survival (PFS) and overall survival (OS) in patients diagnosed with GBM. A comprehensive search was conducted across multiple databases, including PubMed, Embase, Scopus, and The Cochrane Library, covering the period from their inception to December 2022. The collected data underwent analysis employing appropriate statistical methods. Six articles were included in this systematic review and meta-analysis. The addition of bevacizumab to the combination of temozolomide/radiotherapy did not increase the OS in GBM patients. The pooled odds ratio (OR) was 0.843 (95% CI: 0.615-1.156, P = 0.290). The addition of bevacizumab to radiotherapy/temozolomide did not increase the PFS in patients with GBM. The pooled OR was 0.829 (95% CI: 0.561-1.224, P = 0.346). The funnel plot demonstrated the absence of the alleged pleiotropic effects by showing no evidence of observable variability across the estimations. This study does not support the benefit of the addition of bevacizumab to temozolomide and radiotherapy in improving OS and PFS in GBM patients.

Glioblastoma in the oldest old: Clinical characteristics, therapy, and outcome in patients aged 80 years and older

Background

Incidence rates of glioblastoma in very old patients are rising. The standard of care for this cohort is only partially defined and survival remains poor. The aims of this study were to reveal current practice of tumor-specific therapy and supportive care, and to identify predictors for survival in this cohort.

Methods

Patients aged 80 years or older at the time of glioblastoma diagnosis were retrospectively identified in 6 clinical centers in Switzerland and France. Demographics, clinical parameters, and survival outcomes were annotated from patient charts. Cox proportional hazards modeling was performed to identify parameters associated with survival.

Results

Of 107 patients, 45 were diagnosed by biopsy, 30 underwent subtotal resection, and 25 had gross total resection. In 7 patients, the extent of resection was not specified. Postoperatively, 34 patients did not receive further tumor-specific treatment. Twelve patients received radiotherapy with concomitant temozolomide, but only 2 patients had maintenance temozolomide therapy. Fourteen patients received temozolomide alone, 35 patients received radiotherapy alone, 1 patient received bevacizumab, and 1 took part in a clinical trial. Median progression-free survival (PFS) was 3.3 months and median overall survival (OS) was 4.2 months. Among patients who received any postoperative treatment, median PFS was 3.9 months and median OS was 7.2 months. Karnofsky performance status (KPS) ≥70%, gross total resection, and combination therapy were associated with better outcomes. The median time spent hospitalized was 30 days, accounting for 23% of the median OS. End-of-life care was mostly provided by nursing homes (n = 20; 32%) and palliative care wards (n = 16; 26%).

Conclusions

In this cohort of very old patients diagnosed with glioblastoma, a large proportion was treated with best supportive care. Treatment beyond surgery and, in particular, combined modality treatment were associated with longer OS and may be considered for selected patients even at higher ages.

Glioblastoma Therapy: Past, Present and Future

Glioblastoma (GB) stands out as the most prevalent and lethal form of brain cancer. Although great efforts have been made by clinicians and researchers, no significant improvement in survival has been achieved since the Stupp protocol became the standard of care (SOC) in 2005. Despite multimodality treatments, recurrence is almost universal with survival rates under 2 years after diagnosis. Here, we discuss the recent progress in our understanding of GB pathophysiology, in particular, the importance of glioma stem cells (GSCs), the tumor microenvironment conditions, and epigenetic mechanisms involved in GB growth, aggressiveness and recurrence. The discussion on therapeutic strategies first covers the SOC treatment and targeted therapies that have been shown to interfere with different signaling pathways (pRB/CDK4/RB1/P16ink4, TP53/MDM2/P14arf, PI3k/Akt-PTEN, RAS/RAF/MEK, PARP) involved in GB tumorigenesis, pathophysiology, and treatment resistance acquisition. Below, we analyze several immunotherapeutic approaches (i.e., checkpoint inhibitors, vaccines, CAR-modified NK or T cells, oncolytic virotherapy) that have been used in an attempt to enhance the immune response against GB, and thereby avoid recidivism or increase survival of GB patients. Finally, we present treatment attempts made using nanotherapies (nanometric structures having active anti-GB agents such as antibodies, chemotherapeutic/anti-angiogenic drugs or sensitizers, radionuclides, and molecules that target GB cellular receptors or open the blood-brain barrier) and non-ionizing energies (laser interstitial thermal therapy, high/low intensity focused ultrasounds, photodynamic/sonodynamic therapies and electroporation). The aim of this review is to discuss the advances and limitations of the current therapies and to present novel approaches that are under development or following clinical trials.

Targeted Glioma Therapy-Clinical Trials and Future Directions

Glioblastoma multiforme (GBM) is the most common type of glioma, with a median survival of 14.6 months post-diagnosis. Understanding the molecular profile of such tumors allowed the development of specific targeted therapies toward GBM, with a major role attributed to tyrosine kinase receptor inhibitors and immune checkpoint inhibitors. Targeted therapeutics are drugs that work by specific binding to GBM-specific or overexpressed markers on the tumor cellular surface and therefore contain a recognition moiety linked to a cytotoxic agent, which produces an antiproliferative effect. In this review, we have summarized the available information on the targeted therapeutics used in clinical trials of GBM and summarized current obstacles and advances in targeted therapy concerning specific targets present in GBM tumor cells, outlined efficacy endpoints for major classes of investigational drugs, and discussed promising strategies towards an increase in drug efficacy in GBM.

Comparison of the outcomes following bevacizumab and/or temozolamide/radiosurgery treatment in patients with glioblastoma

Glioblastoma multiforme (GBM) is the most frequent and malignant primary central nervous system tumor in adults. The gold-standard management of GBM includes post-operative radiotherapy (RT) with concurrent and secondary temozolomide (TMZ) treatment. The present meta-analysis study examined the efficacy of the early administration of bevacizumab prior to standard RT plus TMZ in managing patients with GBM and unfavorable prognostic factors. Between 1983 and 2020, the present study looked for comparative articles involving standard RT plus TMZ and RT/TMZ combined with bevacizumab treatment in patients with GBM. The primary outcomes involved in this study include progression-free survival and overall survival. The present study suggested that bevacizumab administration plus standard RT/TMZ (BEV group) treatment was associated with increased survival of patients with GBM compared with those treated with standard RT/TMZ (CG/Control group) treatment only.

Antiangiogenic Therapy for Malignant Brain Tumors: Does It Still Matter?

PURPOSE OF REVIEW

To summarize the mechanisms of tumor angiogenesis and resistance to antiangiogenic therapy, and the influence on tumor microenvironment.

RECENT FINDINGS

Several clinical trials have investigated the activity of anti-VEGF monoclonal antibodies and tyrosine kinase inhibitors in glioblastoma, shedding the light on their limitations in terms of disease control and survival. We have outlined the mechanisms of resistance to antiangiogenic therapy, including vessel co-option, hypoxic signaling in response to vessel destruction, modulation of glioma stem cells, and trafficking of tumor-associated macrophages in tumor microenvironment. Moreover, novel generation of antiangiogenic compounds for glioblastoma, including small interfering RNAs and nanoparticles, as a delivery vehicle, could enhance selectivity and reduce side effects of treatments. There is still a rationale for the use of antiangiogenic therapy, but a better understanding of vascular co-option, vascular mimicry, and dynamic relationships between immunosuppressive microenvironment and blood vessel destruction is crucial to develop next-generation antiangiogenic compounds.

Efficacy and Safety of Bevacizumab for Treating Glioblastoma: A Systematic Review and Meta-Analysis of Phase II and III Randomized Controlled Trials

OBJECTIVE

To fully investigate the efficacy and safety of bevacizumab for glioblastoma.

METHODS

Databases were searched for phase II/III randomized controlled trials treated with bevacizumab.

RESULTS

Bevacizumab significantly improved the PFS in glioblastoma patients, but did not prolong OS. PFS was significantly prolonged in both first-line and second-line treatment. Bevacizumab plus temozolomide was correlated with improved PFS for patients with different MGMT methylation status. Bevacizumab could increase the risk of hypertension, proteinuria, thromboembolic, and infection. Hypertension should be well concerned.

CONCLUSIONS

Bevacizumab-containing regimen can significantly improve PFS, but did not prolong OS.

Recent updates on the role of phytochemicals in the treatment of glioblastoma multiforme

ABSTRACTS

Glioblastoma multiforme (GBM) is a malignant type of glioma. This malignant brain tumor is a devastating disease and is often fatal. The spectrum of illness and poor prognosis associated with brain tumors extract a terrible toll on patients and their families. The inoperability of these tumors and resistance to radiation and chemotherapy contribute to the fatal outcome of this disease. Thus, scientists are hunting for the new drug candidate and safer chemoprevention, especially the phytochemicals that possess potent anti-tumor properties. We have summarized the cellular and biochemical impacts of different phytochemicals that can successfully encounter GBM via induction of apoptosis and active interference in different cell and molecular pathways associated with GBM in brain tumors. The in silico predictive model determining the blood-brain barrier permeability of the compound and their potential druggability are discussed in the review.

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.

Optimal managements of elderly patients with glioblastoma

Optimizing the management of elderly patients with glioblastoma is an ongoing task in neuro-oncology. The number of patients with this tumor type is gradually increasing with the aging of the population. Although available data and practice recommendations remain limited, the current strategy is maximal safe surgical resection followed by radiotherapy in combination with temozolomide. However, survival is significantly worse than that in the younger population. Surgical resection provides survival benefit in patients with good performance status. Hypofractionated radiotherapy decreases toxicities while maintaining therapeutic efficacy, thus improving treatment adherence and subsequently leading to better quality of life. The intensity of these treatments should be balanced with patient-specific factors and consideration of quality of life. This review discusses the current optimal management in terms of efficacy and safety, as well as future perspectives.

Glioblastoma, from disease understanding towards optimal cell-based in vitro models

Background

Glioblastoma (GBM) patients are notoriously difficult to treat and ultimately all succumb to disease. This unfortunate scenario motivates research into better characterizing and understanding this disease, and into developing novel research tools by which potential novel therapeutics and treatment options initially can be evaluated pre-clinically. Here, we provide a concise overview of glioblastoma epidemiology, disease classification, the challenges faced in the treatment of glioblastoma and current novel treatment strategies. From this, we lead into a description and assessment of advanced cell-based models that aim to narrow the gap between pre-clinical and clinical studies. Such invitro models are required to deliver reliable and meaningful data for the development and pre-validation of novel therapeutics and treatments.

Conclusions

The toolbox for GBM cell-based models has expanded substantially, with the possibility of 3D printing tumour tissues and thereby replicating invivo tissue architectures now looming on the horizon. A comparison of experimental cell-based model systems and techniques highlights advantages and drawbacks of the various tools available, based on which cell-based models and experimental approaches best suited to address a diversity of research questions in the glioblastoma research field can be selected.

Comparative efficacy and safety of therapeutics for elderly glioblastoma patients: A Bayesian network analysis

Optimal management strategies for elderly glioblastoma (GBM) patients remain elusive. Overall survival (OS) and progression-free survival (PFS) in elderly newly diagnosed GBM (ndGBM) patients were analyzed with random-effects Bayesian network meta-analysis with the estimated hazard ratio (HR) with a 95% confidence interval (95% CrI). In addition, OS, PFS and adverse event (AE) data on ndGBM and recurrent GBM (rGBM) were assessed. Seventeen eligible trials with 12 on ndGBM and 5 on rGBM were identified. For the improvements it induced in the OS of elderly ndGBM patients, tumor treating field (TTF) + temozolomide (TMZ) (HR: 0.11, 95% CrI: 0.02-0.67 vs. supportive care (SPC)) ranked first, followed by TMZ + hyperfractionated radiotherapy (HFRT) (HR: 0.17, 95% CrI: 0.03-0.95 vs. SPC). For the improvements it induced in the PFS of elderly ndGBM patients, bevacizumab (BEV) + HFRT ranked first, followed by TMZ + HFRT. TMZ was observed to be more effective in O6-methylguanine-DNA-methyltransferase (MGMT) promoter-methylated ndGBM patients than HFRT and standard radiotherapy (STRT). For elderly rGBM patients, the treatments included were comparable. The rates of other neurological symptoms (16.1%) and lymphocytopenia (10.4%) were higher in ndGBM patients; lymphocytopenia (10.3%) and infection (8.1%) were higher in rGBM patients among the ≥ 3 grade AEs. TMZ-related AEs should be further considered. In conclusion, TTF + adjuvant TMZ and TMZ + HFRT are most likely to be recommended for elderly ndGBM patients. No best treatment for rGBM in elderly patients is illustrated. TMZ is identified to be more effective in elderly ndGBM patients with methylated MGMT status; however, AEs associated with TMZ-related therapy should be well considered and managed.

Radiotherapy-drug combinations in the treatment of glioblastoma: a brief review

Glioblastoma (GBM) accounts for over 50% of gliomas and carries the worst prognosis of all solid tumors. Owing to the limited local control afforded by surgery alone, efficacious adjuvant treatments such as radiotherapy (RT) and chemotherapy are fundamental in achieving durable disease control. The best clinical outcomes are achieved with tri-modality treatment consisting of surgery, RT and systemic therapy. While RT-chemotherapy combination regimens are well established in oncology, this approach was largely unsuccessful in GBM until the introduction of temozolomide. The success of this combination has stimulated the search for other candidate drugs for concomitant use with RT in GBM. This review seeks to collate the current evidence for these agents and synthesize possible future directions for the field.

Optimizing Postoperative Adjuvant Therapy in Elderly Patients with Newly Diagnosed Glioblastoma: Single-Institution Audit of Clinical Outcomes from a Tertiary-Care Comprehensive Cancer Center in India

BACKGROUND

There is lack of consensus regarding optimal adjuvant therapy in elderly glioblastoma (GBM). We have been treating elderly (≥60 years) GBM patients with normofractionated or hypofractionated radiotherapy (RT) plus temozolomide (TMZ) based on Karnofsky performance status (KPS). Herein we report clinical outcomes in this cohort treated at our institute using this approach.

METHODS

Medical records of elderly GBM patients (≥60 years) treated between 2013 and 2017 with either normofractionated RT (59.4-60 Gy/30-33 fractions/6-6.5 weeks) or hypofractionated RT (35 Gy/10 fractions/2 weeks) plus TMZ were reviewed retrospectively. Outcomes of interest included progression-free survival (PFS), overall survival (OS), and ≥grade 3 myelotoxicity. Time-to-event outcomes were analyzed with Kaplan-Meier methods, compared using log-rank test, and reported as point estimates with 95% confidence interval (CI).

RESULTS

The normofractionated cohort (n = 126) was characterized by a higher proportion of patients younger than age 65 years, KPS ≥70, methylated O⁶-methylguanine DNA methyltransferase (MGMT), and receiving adjuvant TMZ including extended adjuvant TMZ (>6 cycles) compared with the hypofractionated cohort (n = 20), confirming selection bias. At a median follow-up of 13 months, 1-year Kaplan-Meier estimates of PFS and OS were 43% (95% CI: 36%-52%) and 56% (95% CI: 48%-64%), yielding median PFS and OS of 11.0 months and 13.1 months, respectively. Higher KPS, methylated MGMT, normofractionated RT, and extended adjuvant TMZ emerged as favorable prognostic factors. TMZ was well tolerated with a low risk of ≥grade 3 myelotoxicity.

CONCLUSIONS

Our single-institution clinical audit confirms poor survival in elderly GBM with suboptimal performance status but demonstrates acceptably fair outcomes in patients with preserved KPS comparable with the nonelderly cohort.

Increased Expression of Homeobox 5 Predicts Poor Prognosis: A Potential Prognostic Biomarker for Glioma

Background

The homeobox gene 5 (HOXB5) encodes a transcription factor that regulates the embryonic development of the central nervous system. Notably, its expression pattern and prognostic role in glioma remain unelucidated.

Methods

This study identified the relationship between HOXB5 and glioma by investigating HOXB5 expression data from The Cancer Genome Atlas and the Genotype Tissue Expression databases and validating the obtained data using the Chinese Glioma Genome Atlas database. Western blots were used to identify HOXB5 expression levels in glioma cells and clinical samples. Kaplan-Meier and multivariate Cox regression analyses were performed to assess the prognostic value of HOXB5. The key functions and signaling pathways related to HOXB5 were analyzed using GO, KEGG, and GSEA. Immune infiltration was calculated using the microenvironment cell populations-counter, estimate the proportion of immune and cancer, and ESTIMATE algorithms.

Results

The expression of HOXB5 was upregulated in glioma and generally increased with malignancy. HOXB5 was an independent prognostic factor for glioma patients. A nomogram was further built that integrated HOXB5, and it showed stratifying prediction accuracy and efficiency. HOXB5 was associated with the regulation of cell growth, endothelial cell growth, and the IL-6/JAK-STAT3 pathway, and was determined to possibly promote stomatal specimen enrichment and angiogenesis.

Conclusion

HOXB5 protein is overexpressed in glioma and might serve as a good predictive factor of this disease.

Newly Diagnosed Glioblastoma in Elderly Patients

Purpose of Review

Elderly patients with newly diagnosed glioblastoma (eGBM) carry a worse prognosis compared with their younger counterparts. eGBM garners special attention due to the unique challenges, including increased treatment-associated toxicity, less relative benefit from aggressive therapy, medical comorbidities, and immunosuppression. The pivotal GBM trials excluded patients > 70 years old and the optimal treatment approach remains unsettled for eGBM. In this review, we analyze the historical evidence-based data for treating eGBM and discuss the future direction for managing this vulnerable population.

Recent Findings

Treatment for eGBM continues to evolve. Therapy choice is guided by performance status and presence of O6-methylguanine-DNA-methyltransferase (MGMT) promoter methylation. For eGBM with good performance status, combinatorial hypofractionated radiation therapy (hRT) and temozolomide should be recommended. For those with poor performance status, further stratification based on MGMT promoter methylation test result is recommended. Single-agent temozolomide is a viable treatment option for MGMT methylated tumors (mMGMT); in particular, those classified with receptor tyrosine kinase II methylation. hRT alone can be considered in MGMT unmethylated (uMGMT) eGBM patients. As precision oncology continues to advance, effective targeted and immunotherapy may emerge as new treatment options for eGBM.

Summary

Management of elderly patients with newly diagnosed GBM carries a unique set of challenges. Progress has been made in defining the optimal therapeutic approach for these patients, but many questions remain to be answered.

Clinical strategies to manage adult glioblastoma patients without MGMT hypermethylation

Glioblastoma (GBM) is a highly malignant brain tumor with a dismal prognosis. Standard therapy for GBM comprises surgical resection, followed by radiotherapy plus concomitant and adjuvant temozolomide (TMZ) therapy. The methylation status of the O6-methylguanine DNA methyltransferase (MGMT) promoter is one of the most essential predictive biomarkers for patients with GBM treated with TMZ. Patients with an unmethylated MGMT promoter (umMGMT), who comprise 60% of patients with GBM, present an even worse prognosis because of TMZ resistance. Radiotherapy with various fractionation, chemotherapy compensating for TMZ, targeted therapy against diverse oncogenic pathways, immunotherapy of vaccine or immune checkpoint inhibitor, and tumor treating fields have been studied in umMGMT GBM patients. However, most efforts have yielded negative results or merely minimal improvements. Therefore, effective patient subgroup selection concerning precision medicine has become the focus. By assigning different treatments to the corresponding patient subgroups, a better curative effect and subsequently prolonged survival can be achieved. In this review, we re-evaluate the value of standard TMZ therapy and summarize the new clinical strategies and attempts to treat patients with umMGMT, which yielded positive and negative results, to provide alternative treatment options and discuss future directions of umMGMT GBM treatment.

Therapy for Diffuse Astrocytic and Oligodendroglial Tumors in Adults: ASCO-SNO Guideline

Purpose

To provide guidance to clinicians regarding therapy for diffuse astrocytic and oligodendroglial tumors in adults.

Methods

ASCO and the Society for Neuro-Oncology convened an Expert Panel and conducted a systematic review of the literature.

Results

Fifty-nine randomized trials focusing on therapeutic management were identified.

Recommendations

Adults with newly diagnosed oligodendroglioma, isocitrate dehydrogenase (IDH)–mutant, 1p19q codeleted CNS WHO grade 2 and 3 should be offered radiation therapy (RT) and procarbazine, lomustine, and vincristine (PCV). Temozolomide (TMZ) is a reasonable alternative for patients who may not tolerate PCV, but no high-level evidence supports upfront TMZ in this setting. People with newly diagnosed astrocytoma, IDH-mutant, 1p19q non-codeleted CNS WHO grade 2 should be offered RT with adjuvant chemotherapy (TMZ or PCV). People with astrocytoma, IDH-mutant, 1p19q non-codeleted CNS WHO grade 3 should be offered RT and adjuvant TMZ. People with astrocytoma, IDH-mutant, CNS WHO grade 4 may follow recommendations for either astrocytoma, IDH-mutant, 1p19q non-codeleted CNS WHO grade 3 or glioblastoma, IDH-wildtype, CNS WHO grade 4. Concurrent TMZ and RT should be offered to patients with newly diagnosed glioblastoma, IDH-wildtype, CNS WHO grade 4 followed by 6 months of adjuvant TMZ. Alternating electric field therapy, approved by the US Food and Drug Administration, should be considered for these patients. Bevacizumab is not recommended. In situations in which the benefits of 6-week RT plus TMZ may not outweigh the harms, hypofractionated RT plus TMZ is reasonable. In patients age ≥ 60 to ≥ 70 years, with poor performance status or for whom toxicity or prognosis are concerns, best supportive care alone, RT alone (for MGMTpromoter unmethylated tumors), or TMZ alone (for MGMT promoter methylated tumors) are reasonable treatment options. Additional information is available at www.asco.org/neurooncology-guidelines.

Therapy for Diffuse Astrocytic and Oligodendroglial Tumors in Adults: ASCO-SNO Guideline

PURPOSE

To provide guidance to clinicians regarding therapy for diffuse astrocytic and oligodendroglial tumors in adults.

METHODS

ASCO and the Society for Neuro-Oncology convened an Expert Panel and conducted a systematic review of the literature.

RESULTS

Fifty-nine randomized trials focusing on therapeutic management were identified.

RECOMMENDATIONS

Adults with newly diagnosed oligodendroglioma, isocitrate dehydrogenase (IDH)-mutant, 1p19q codeleted CNS WHO grade 2 and 3 should be offered radiation therapy (RT) and procarbazine, lomustine, and vincristine (PCV). Temozolomide (TMZ) is a reasonable alternative for patients who may not tolerate PCV, but no high-level evidence supports upfront TMZ in this setting. People with newly diagnosed astrocytoma, IDH-mutant, 1p19q non-codeleted CNS WHO grade 2 should be offered RT with adjuvant chemotherapy (TMZ or PCV). People with astrocytoma, IDH-mutant, 1p19q non-codeleted CNS WHO grade 3 should be offered RT and adjuvant TMZ. People with astrocytoma, IDH-mutant, CNS WHO grade 4 may follow recommendations for either astrocytoma, IDH-mutant, 1p19q non-codeleted CNS WHO grade 3 or glioblastoma, IDH-wildtype, CNS WHO grade 4. Concurrent TMZ and RT should be offered to patients with newly diagnosed glioblastoma, IDH-wildtype, CNS WHO grade 4 followed by 6 months of adjuvant TMZ. Alternating electric field therapy, approved by the US Food and Drug Administration, should be considered for these patients. Bevacizumab is not recommended. In situations in which the benefits of 6-week RT plus TMZ may not outweigh the harms, hypofractionated RT plus TMZ is reasonable. In patients age ≥ 60 to ≥ 70 years, with poor performance status or for whom toxicity or prognosis are concerns, best supportive care alone, RT alone (for MGMT promoter unmethylated tumors), or TMZ alone (for MGMT promoter methylated tumors) are reasonable treatment options. Additional information is available at www.asco.org/neurooncology-guidelines.

Isocitrate Dehydrogenase Wild-type Glial Tumors, Including Glioblastoma

Isocitrate dehydrogenase (IDH) 1 and 2 mutations represent essential components for the diagnosis of diffuse astrocytic tumors and oligodendroglioma. IDH wild-type glial tumors include a wide spectrum of tumors with differences in prognosis and recommended therapeutic approaches. Tumors characterized as molecular glioblastoma in the World Health Organization 2021 classification should be treated according to the glioblastoma therapeutic principles and included in glioblastoma trials. Improving on existing treatments options including targeted and immunotherapy approaches is imperative for most patients with IDH wild-type glial tumors, and enrollment in clinical trials is encouraged.

Novel Receptor Tyrosine Kinase Pathway Inhibitors for Targeted Radionuclide Therapy of Glioblastoma

Glioblastoma (GB) remains the most fatal brain tumor characterized by a high infiltration rate and treatment resistance. Overexpression and/or mutation of receptor tyrosine kinases is common in GB, which subsequently leads to the activation of many downstream pathways that have a critical impact on tumor progression and therapy resistance. Therefore, receptor tyrosine kinase inhibitors (RTKIs) have been investigated to improve the dismal prognosis of GB in an effort to evolve into a personalized targeted therapy strategy with a better treatment outcome. Numerous RTKIs have been approved in the clinic and several radiopharmaceuticals are part of (pre)clinical trials as a non-invasive method to identify patients who could benefit from RTKI. The latter opens up the scope for theranostic applications. In this review, the present status of RTKIs for the treatment, nuclear imaging and targeted radionuclide therapy of GB is presented. The focus will be on seven tyrosine kinase receptors, based on their central role in GB: EGFR, VEGFR, MET, PDGFR, FGFR, Eph receptor and IGF1R. Finally, by way of analyzing structural and physiological characteristics of the TKIs with promising clinical trial results, four small molecule RTKIs were selected based on their potential to become new therapeutic GB radiopharmaceuticals.

A Systematic Review of Glioblastoma-Targeted Therapies in Phases II, III, IV Clinical Trials

Glioblastoma (GBM), the most frequent and aggressive glial tumor, is currently treated as first line by the Stupp protocol, which combines, after surgery, radiotherapy and chemotherapy. For recurrent GBM, in absence of standard treatment or available clinical trials, various protocols including cytotoxic drugs and/or bevacizumab are currently applied. Despite these heavy treatments, the mean overall survival of patients is under 18 months. Many clinical studies are underway. Based on clinicaltrials.org and conducted up to 1 April 2020, this review lists, not only main, but all targeted therapies in phases II-IV of 257 clinical trials on adults with newly diagnosed or recurrent GBMs for the last twenty years. It does not involve targeted immunotherapies and therapies targeting tumor cell metabolism, that are well documented in other reviews. Without surprise, the most frequently reported drugs are those targeting (i) EGFR (40 clinical trials), and more generally tyrosine kinase receptors (85 clinical trials) and (ii) VEGF/VEGFR (75 clinical trials of which 53 involving bevacizumab). But many other targets and drugs are of interest. They are all listed and thoroughly described, on an one-on-one basis, in four sections related to targeting (i) GBM stem cells and stem cell pathways, (ii) the growth autonomy and migration, (iii) the cell cycle and the escape to cell death, (iv) and angiogenesis.

The Normal and Brain Tumor Vasculature: Morphological and Functional Characteristics and Therapeutic Targeting

Glioblastoma is among the most common tumor of the central nervous system in adults. Overall survival has not significantly improved over the last decade, even with optimizing standard therapeutic care including extent of resection and radio- and chemotherapy. In this article, we review features of the brain vasculature found in healthy cerebral tissue and in glioblastoma. Brain vessels are of various sizes and composed of several vascular cell types. Non-vascular cells such as astrocytes or microglia also interact with the vasculature and play important roles. We also discuss in vitro engineered artificial blood vessels which may represent useful models for better understanding the tumor-vessel interaction. Finally, we summarize results from clinical trials with anti-angiogenic therapy alone or in combination, and discuss the value of these approaches for targeting glioblastoma.

A vasculature-centric approach to developing novel treatment options for glioblastoma

Introduction: Glioblastoma is invariably deadly and is characterized by extensive vascularization and macrophage-dominant immunosuppression; nevertheless, anti-angiogenesis has so far failed to prolong overall survival of patients. Regardless of the problems in clinical development, the rationale for the application of anti-angiogenics in glioblastoma remains.Areas covered: Resistance to anti-angiogenics is discussed, including vessel co-option and amplification of hypoxic signaling in response to vessel destruction. The modulation of GSC and tumor-associated macrophages by dysfunctional tumor vessels and by hypoxia are outlined. Pharmacologic approaches to sensitizing glioblastomas to anti-angiogenics and evidence for the cooperation of anti-angiogenics with immunotherapies are summarized. Database search: https://pubmed.ncbi.nlm.nih.gov prior to December 12, 2020.Expert opinion: Despite drawbacks in the clinical development of vascular endothelial growth factor A (VEGF)-targeted agents, there is still rationale for the use of anti-angiogenics. The better understanding of vascular co-option and adverse effects of blood vessel destruction guides to improve strategies for vascular targeting. The pivotal role of the vasculature and of angiogenic factors such as VEGF for the induction and maintenance of immunosuppression in glioblastoma supports the use of anti-angiogenics in combination with immunotherapy. Proinflammatory repolarization of perivascular and perinecrotic tumor-associated macrophages is probably paramount for overcoming treatment resistance to virtually any treatment.

Development of a gene expression-based prognostic signature for IDH wild-type glioblastoma

BACKGROUND

We aimed to develop a gene expression-based prognostic signature for isocitrate dehydrogenase (IDH) wild-type glioblastoma using clinical trial datasets representative of glioblastoma clinical trial populations.

METHODS

Samples were collected from newly diagnosed patients with IDH wild-type glioblastoma in the ARTE, TAMIGA, EORTC 26101 (referred to as "ATE"), AVAglio, and GLARIUS trials, or treated at UCLA. Transcriptional profiling was achieved with the NanoString gene expression platform. To identify genes prognostic for overall survival (OS), we built an elastic net penalized Cox proportional hazards regression model using the discovery ATE dataset. For validation in independent datasets (AVAglio, GLARIUS, UCLA), we combined elastic net-selected genes into a robust z-score signature (ATE score) to overcome gene expression platform differences between discovery and validation cohorts.

RESULTS

NanoString data were available from 512 patients in the ATE dataset. Elastic net identified a prognostic signature of 9 genes (CHEK1, GPR17, IGF2BP3, MGMT, MTHFD1L, PTRH2, SOX11, S100A9, and TFRC). Translating weighted elastic net scores to the ATE score conserved the prognostic value of the genes. The ATE score was prognostic for OS in the ATE dataset (P < 0.0001), as expected, and in the validation cohorts (AVAglio, P < 0.0001; GLARIUS, P = 0.02; UCLA, P = 0.004). The ATE score remained prognostic following adjustment for O6-methylguanine-DNA methyltransferase (MGMT) promoter methylation status and corticosteroid use at baseline. A positive correlation between ATE score and proneural/proliferative subtypes was observed in patients with MGMT non-methylated promoter status.

CONCLUSIONS

The ATE score showed prognostic value and may enable clinical trial stratification for IDH wild-type glioblastoma.

Update on Chemotherapeutic Approaches and Management of Bevacizumab Usage for Glioblastoma

Glioblastoma, the most common primary brain tumor in adults, has one of the most dismal prognoses in cancer. In 2009, bevacizumab was approved for recurrent glioblastoma in the USA. To evaluate the clinical impact of bevacizumab as a first-line drug for glioblastoma, two randomized clinical trials, AVAglio and RTOG 0825, were performed. Bevacizumab was found to improve progression-free survival (PFS) and was reported to be beneficial for maintaining patient performance status as an initial treatment. These outcomes led to bevacizumab approval in Japan in 2013 as an insurance-covered first-line drug for glioblastoma concurrently with its second-line application. However, prolongation of overall survival was not evinced in these clinical trials; hence, the clinical benefit of bevacizumab for newly diagnosed glioblastomas remains controversial. A recent meta-analysis of randomized controlled trials of bevacizumab combined with temozolomide in recurrent glioblastoma also showed an effect only on PFS, and the benefit of bevacizumab even for recurrent glioblastoma is controversial. Here, we discuss the clinical impact of bevacizumab for glioblastoma treatment by reviewing previous clinical trials and real-world evidence by focusing on Japanese experiences. Moreover, the efficacy and safety of bevacizumab are summarized, and we provide suggestions for updating the approaches and management of bevacizumab.

EANO guidelines on the diagnosis and treatment of diffuse gliomas of adulthood

In response to major changes in diagnostic algorithms and the publication of mature results from various large clinical trials, the European Association of Neuro-Oncology (EANO) recognized the need to provide updated guidelines for the diagnosis and management of adult patients with diffuse gliomas. Through these evidence-based guidelines, a task force of EANO provides recommendations for the diagnosis, treatment and follow-up of adult patients with diffuse gliomas. The diagnostic component is based on the 2016 update of the WHO Classification of Tumors of the Central Nervous System and the subsequent recommendations of the Consortium to Inform Molecular and Practical Approaches to CNS Tumour Taxonomy — Not Officially WHO (cIMPACT-NOW). With regard to therapy, we formulated recommendations based on the results from the latest practice-changing clinical trials and also provide guidance for neuropathological and neuroradiological assessment. In these guidelines, we define the role of the major treatment modalities of surgery, radiotherapy and systemic pharmacotherapy, covering current advances and cognizant that unnecessary interventions and expenses should be avoided. This document is intended to be a source of reference for professionals involved in the management of adult patients with diffuse gliomas, for patients and caregivers, and for health-care providers.

Herein, the European Association of Neuro-Oncology (EANO) provides recommendations for the diagnosis, treatment and follow-up of adult patients with diffuse gliomas. These evidence-based guidelines incorporate major changes in diagnostic algorithms based on the 2016 update of the WHO Classification of Tumors of the Central Nervous System as well as on evidence from recent large clinical trials.

Congress of neurological surgeons systematic review and evidence-based guidelines update on the role of emerging developments in the management of newly diagnosed glioblastoma

TARGET POPULATION

These recommendations apply to adult patients with newly diagnosed or suspected glioblastoma.

IMAGING

Question What imaging modalities are in development that may be able to provide improvements in diagnosis, and therapeutic guidance for individuals with newly diagnosed glioblastoma?

RECOMMENDATION

Level III: It is suggested that techniques utilizing magnetic resonance imaging for diffusion weighted imaging, and to measure cerebral blood and magnetic spectroscopic resonance imaging of N-acetyl aspartate, choline and the choline to N-acetyl aspartate index to assist in diagnosis and treatment planning in patients with newly diagnosed or suspected glioblastoma.

SURGERY

Question What new surgical techniques can be used to provide improved tumor definition and resectability to yield better tumor control and prognosis for individuals with newly diagnosed glioblastoma?

RECOMMENDATIONS

Level II: The use of 5-aminolevulinic acid is recommended to improve extent of tumor resection in patients with newly diagnosed glioblastoma. Level II: The use of 5-aminolevulinic acid is recommended to improve median survival and 2 year survival in newly diagnosed glioblastoma patients with clinical characteristics suggesting poor prognosis. Level III: It is suggested that, when available, patients be enrolled in properly designed clinical trials assessing the value of diffusion tensor imaging in improving the safety of patients with newly diagnosed glioblastoma undergoing surgery.

NEUROPATHOLOGY

Question What new pathology techniques and measurement of biomarkers in tumor tissue can be used to provide improved diagnostic ability, and determination of therapeutic responsiveness and prognosis for patients with newly diagnosed glioblastomas?

RECOMMENDATIONS

Level II: Assessment of tumor MGMT promoter methylation status is recommended as a significant predictor of a longer progression free survival and overall survival in patients with newly diagnosed with glioblastoma. Level II: Measurement of tumor expression of neuron-glia-2, neurofilament protein, glutamine synthetase and phosphorylated STAT3 is recommended as a predictor of overall survival in patients with newly diagnosed with glioblastoma. Level III: Assessment of tumor IDH1 mutation status is suggested as a predictor of longer progression free survival and overall survival in patients with newly diagnosed with glioblastoma. Level III: Evaluation of tumor expression of Phosphorylated Mitogen-Activated Protein Kinase protein, EGFR protein, and Insulin-like Growth Factor-Binding Protein-3 is suggested as a predictor of overall survival in patients with newly diagnosed with glioblastoma.

RADIATION

Question What radiation therapy techniques are in development that may be used to provide improved tumor control and prognosis for individuals with newly diagnosed glioblastomas?

RECOMMENDATIONS

Level III: It is suggested that patients with newly diagnosed glioblastoma undergo pretreatment radio-labeled amino acid tracer positron emission tomography to assess areas at risk for tumor recurrence to assist in radiation treatment planning. Level III: It is suggested that, when available, patients be with newly diagnosed glioblastomas be enrolled in properly designed clinical trials of radiation dose escalation, altered fractionation, or new radiation delivery techniques.

CHEMOTHERAPY

Question What emerging chemotherapeutic agents or techniques are available to provide better tumor control and prognosis for patients with newly diagnosed glioblastomas?

RECOMMENDATION

Level III: As no emerging chemotherapeutic agents or techniques were identified in this review that improved tumor control and prognosis it is suggested that, when available, patients with newly diagnosed glioblastomas be enrolled in properly designed clinical trials of chemotherapy.

MOLECULAR AND TARGETED THERAPY

Question What new targeted therapy agents are available to provide better tumor control and prognosis for individuals with newly diagnosed glioblastomas?

RECOMMENDATION

Level III: As no new molecular and targeted therapies have clearly provided better tumor control and prognosis it is suggested that, when available, patients with newly diagnosed glioblastomas be enrolled in properly designed clinical trials of molecular and targeted therapies IMMUNOTHERAPY: Question What emerging immunotherapeutic agents or techniques are available to provide better tumor control and prognosis for patients with newly diagnosed glioblastomas?

RECOMMENDATION

Level III: As no immunotherapeutic agents have clearly provided better tumor control and prognosis it is suggested that, when available, patients with newly diagnosed glioblastomas be enrolled in properly designed clinical trials of immunologically-based therapies.

NOVEL THERAPIES

Question What novel therapies or techniques are in development to provide better tumor control and prognosis for individuals with newly diagnosed glioblastomas?

RECOMMENDATIONS

Level II: The use of tumor-treating fields is recommended for patients with newly diagnosed glioblastoma who have undergone surgical debulking and completed concurrent chemoradiation without progression of disease at the time of tumor-treating field therapy initiation. Level II: It is suggested that, when available, enrollment in properly designed studies of vector containing herpes simplex thymidine kinase gene and prodrug therapies be considered in patients with newly diagnosed glioblastoma.

Disentangling the therapeutic tactics in GBM: From bench to bedside and beyond

Glioblastoma multiforme (GBM) is one of the most common and malignant form of adult brain tumor with a high mortality rate and dismal prognosis. The present standard treatment comprising surgical resection followed by radiation and chemotherapy using temozolomide can broaden patient's survival to some extent. However, the advantages are not palliative due to the development of resistance to the drug and tumor recurrence following the multimodal treatment approaches due to both intra- and intertumoral heterogeneity of GBM. One of the major contributors to temozolomide resistance is O⁶ -methylguanine-DNA methyltransferase. Furthermore, deficiency of mismatch repair, base excision repair, and cytoprotective autophagy adds to temozolomide obstruction. Rising proof additionally showed that a small population of cells displaying certain stem cell markers, known as glioma stem cells, adds on to the resistance and tumor progression. Collectively, these findings necessitate the discovery of novel therapeutic avenues for treating glioblastoma. As of late, after understanding the pathophysiology and biology of GBM, some novel therapeutic discoveries, such as drug repurposing, targeted molecules, immunotherapies, antimitotic therapies, and microRNAs, have been developed as new potential treatments for glioblastoma. To help illustrate, "what are the mechanisms of resistance to temozolomide" and "what kind of alternative therapeutics can be suggested" with this fatal disease, a detailed history of these has been discussed in this review article, all with a hope to develop an effective treatment strategy for GBM.

Current clinical management of elderly patients with glioma

INTRODUCTION

The incidence of gliomas is increasing in elderly patients. Clinical factors, such as age, performance status, and comorbidities contribute when choosing adequate treatment in older patients.

AREAS COVERED

This review covers the main pathological and molecular features of gliomas in elderly patients, as well as the neurological and geriatric assessment to select patients for surgery and antineoplastic treatments. The results from the most relevant clinical trials in both lower-grade (LGGs) and high-grade gliomas (HGGs) are reviewed.

EXPERT OPINION

Different clinical and biological factors need to be integrated into prognostic scales in order to better stratify the elderly population. Both Stupp and Perry regimens can be proposed to fit patients with GBM aged < 70 years. Conversely, for patients aged ≥ 70 years, the Perry regimen should be preferred. For unfit and frail patients, temozolomide alone when MGMT is methylated or hypofractionated RT alone when MGMT is unmethylated, are the optimal choice. Few data are available regarding the optimal management of elderly patients with LGGs. The benefit of an extensive resection and presence of methylation of the MGMT promoter need to be further investigated to confirm their role in improving the OS.

Incorporating genomic signatures into surgical and medical decision-making for elderly glioblastoma patients

Glioblastoma (GBM) is the most common type of malignant primary brain tumor in adults. It is a uniformly fatal disease (median overall survival 16 months) even with aggressive resection and an adjuvant temozolomide-based chemoradiation regimen. Age remains an independent risk factor for a poor prognosis. Several factors contribute to the dismal outcomes in the elderly population with GBM, including poor baseline health status, differences in underlying genomic alterations, and variability in the surgical and medical management of this subpopulation. The latter arises from a lack of adequate representation of elderly patients in clinical trials, resulting in limited data on the response of this subpopulation to standard treatment. Results from retrospective and some prospective studies have indicated that resection of only contrast-enhancing lesions and administration of hypofractionated radiotherapy in combination with temozolomide are effective strategies for optimizing survival while maintaining baseline quality of life in elderly GBM patients; however, survival remains dismal relative to that in a younger cohort. Here, the authors present historical context for the current strategies used for the multimodal management (surgical and medical) of elderly patients with GBM. Furthermore, they provide insights into elderly GBM patient-specific genomic signatures such as isocitrate dehydrogenase 1/2 (IDH1/2) wildtype status, telomerase reverse transcriptase promoter (TERTp) mutations, and somatic copy number alterations including CDK4/MDM2 coamplification, which are becoming better understood and could be utilized in a clinical trial design and patient stratification to guide the development of more effective adjuvant therapies specifically for elderly GBM patients.

MRI and 18FET-PET Predict Survival Benefit from Bevacizumab Plus Radiotherapy in Patients with Isocitrate Dehydrogenase Wild-type Glioblastoma: Results from the Randomized ARTE Trial

PURPOSE

To explore a prognostic or predictive role of MRI and O-(2-¹⁸F-fluoroethyl)-L-tyrosine (¹⁸FET) PET parameters for outcome in the randomized multicenter trial ARTE that compared bevacizumab plus radiotherapy with radiotherpay alone in elderly patients with glioblastoma.

PATIENTS AND METHODS

Patients with isocitrate dehydrogenase wild-type glioblastoma ages 65 years or older were included in this post hoc analysis. Tumor volumetric and apparent diffusion coefficient (ADC) analyses of serial MRI scans from 67 patients and serial ¹⁸FET-PET tumor-to-brain intensity ratios (TBRs) from 31 patients were analyzed blinded for treatment arm and outcome. Multivariate Cox regression analysis was done to account for established prognostic factors and treatment arm.

RESULTS

Overall survival benefit from bevacizumab plus radiotherapy compared with radiotherapy alone was observed for larger pretreatment MRI contrast-enhancing tumor [HR per cm³ 0.94; 95% confidence interval (CI), 0.89-0.99] and for higher ADC (HR 0.18; CI, 0.05-0.66). Higher ¹⁸FET-TBR on pretreatment PET scans was associated with inferior overall survival in both arms. Response assessed by standard MRI-based Response Assessment in Neuro-Oncology criteria was associated with overall survival in the bevacizumab plus radiotherapy arm by trend only (P = 0.09). High ¹⁸FET-TBR of noncontrast-enhancing tumor portions during bevacizumab therapy was associated with inferior overall survival on multivariate analysis (HR 5.97; CI, 1.16-30.8).

CONCLUSIONS

Large pretreatment contrast-enhancing tumor mass and higher ADCs identify patients who may experience a survival benefit from bevacizumab plus radiotherapy. Persistent ¹⁸FET-PET signal of no longer contrast-enhancing tumor after concomitant bevacizumab plus radiotherapy suggests pseudoresponse and predicts poor outcome.

Glioblastoma in adults: a Society for Neuro-Oncology (SNO) and European Society of Neuro-Oncology (EANO) consensus review on current management and future directions

Glioblastomas are the most common form of malignant primary brain tumor and an important cause of morbidity and mortality. In recent years there have been important advances in understanding the molecular pathogenesis and biology of these tumors, but this has not translated into significantly improved outcomes for patients. In this consensus review from the Society for Neuro-Oncology (SNO) and the European Association of Neuro-Oncology (EANO), the current management of isocitrate dehydrogenase wildtype (IDHwt) glioblastomas will be discussed. In addition, novel therapies such as targeted molecular therapies, agents targeting DNA damage response and metabolism, immunotherapies, and viral therapies will be reviewed, as well as the current challenges and future directions for research.

Proteasome inhibition for the treatment of glioblastoma

INTRODUCTION

Glioblastoma is a primary brain tumor with a poor prognosis despite multimodal therapy including surgery, radiotherapy and alkylating chemotherapy. Novel therapeutic options are therefore urgently needed; however, there have been various drug failures in late-stage clinical development. The proteasome represents a key target for anti-cancer therapy as successfully shown in multiple myeloma and other hematologic malignancies.

AREAS COVERED

This review article summarizes the preclinical and clinical development of proteasome inhibitors in the context of glioblastoma.

EXPERT OPINION

Early clinical trials with bortezomib ended with disappointing results, possibly because this agent does not cross the blood-brain barrier. In contrast to bortezomib and other proteasome inhibitors, marizomib is a novel drug that displays strong inhibitory properties on all enzymatic subunits of the proteasome and, most importantly, crosses the blood-brain barrier, making it a potentially very active novel agent against intrinsic brain tumors. While preclinical studies have demonstrated significant anti-glioma activity, its clinical benefit has yet to be proven. Exploiting the biological effects of proteasome inhibitors in combination with other therapeutic strategies may represent a key next step in their clinical development.

Guiding Treatment Choices for Elderly Patients with Glioblastoma by a Comprehensive Geriatric Assessment

PURPOSE OF REVIEW

The incidence of glioblastoma multiforme (GBM) increases with age; more than half of newly diagnosed patients are older than 65 years. Due to age-dependent decreasing organ functions, comorbidities, functional decline, and increasing risk of social isolation, not all patients are able to tolerate standard therapy of GBM with 6 weeks of radiochemotherapy.

RECENT FINDINGS

A set of alleviated therapies, e.g., chemotherapy or radiotherapy alone, hypofractionated radiotherapies with different total doses and variable fractionation regimens as well as hypofractionated radiotherapy with concomitant and adjuvant chemotherapy, have been evaluated during the last years. However, clinicians are still unsure which therapy would fit best to a given patient. Recently, the predictive value of comprehensive geriatric assessment regarding tolerance of chemotherapy and prediction of early mortality has been validated for older GBM patients in a retrospective trial. Thus, it appears that neuro-oncology is now ready for the prospective implementation of geriatric assessment to guide treatment planning for elderly GBM patients.

Management of glioblastomas in the elderly population

Glioblastoma multiforme (GBM) is the most common primary brain tumor in adults. The incidence of malignant gliomas is growing in the elderly population. Unfortunately, increasing age is one of the most important negative prognostic factors for this tumor. For a long time, the treatment of elderly patients with GBM was controversial. Currently, more active strategies are the rule. Indeed, as in the younger population, prospective randomized studies have recently established the benefit of radiotherapy associated with concomitant and adjuvant chemotherapy by temozolomide in older patients suffering from malignant gliomas with good functional status. The application of chemotherapy alone may be especially useful in patients with poor functional status and O-6-methylguanine-DNA methyltransferase (MGMT) promotor methylation. For the portion of the elderly population identified as frail, treatment decisions should be made in the context of a comprehensive geriatric evaluation while also taking into account quality of life and concomitant pathologies. The willingness of the patient and his or her caregivers will also be key to the therapeutic decision. Symptomatic treatments such as corticosteroids and antiepileptic drugs may be less tolerated in this population compared to younger patients and should be used only if requested. In the future, it will be necessary to continue to develop specific schedules of treatment in the frail population. For this reason, prospective randomized clinical trials are still needed to pursue improvements in the pattern of care of malignant glioma in elderly individuals.

Glioblastoma: Pathogenesis and Current Status of Chemotherapy and Other Novel Treatments

Glioblastoma is one of the most common and detrimental forms of solid brain tumor, with over 10,000 new cases reported every year in the United States. Despite aggressive multimodal treatment approaches, the overall survival period is reported to be less than 15 months after diagnosis. A widely used approach for the treatment of glioblastoma is surgical removal of the tumor, followed by radiotherapy and chemotherapy. While there are several drugs available that are approved by the Food and Drug Administration (FDA), significant efforts have been made in recent years to develop new chemotherapeutic agents for the treatment of glioblastoma. This review describes the molecular targets and pathogenesis as well as the current progress in chemotherapeutic development and other novel therapies in the clinical setting for the treatment of glioblastoma.

Treatment of newly diagnosed glioblastoma in the elderly: a network meta-analysis

BACKGROUND

A glioblastoma is a fatal type of brain tumour for which the standard of care is maximum surgical resection followed by chemoradiotherapy, when possible. Age is an important consideration in this disease, as older age is associated with shorter survival and a higher risk of treatment-related toxicity.

OBJECTIVES

To determine the most effective and best-tolerated approaches for the treatment of elderly people with newly diagnosed glioblastoma. To summarise current evidence for the incremental resource use, utilities, costs and cost-effectiveness associated with these approaches.

SEARCH METHODS

We searched electronic databases including the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE and Embase to 3 April 2019, and the NHS Economic Evaluation Database (EED) up to database closure. We handsearched clinical trial registries and selected neuro-oncology society conference proceedings from the past five years.

SELECTION CRITERIA

Randomised trials (RCTs) of treatments for glioblastoma in elderly people. We defined 'elderly' as 70+ years but included studies defining 'elderly' as over 65+ years if so reported.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods for study selection and data extraction. Where sufficient data were available, treatment options were compared in a network meta-analysis (NMA) using Stata software (version 15.1). For outcomes with insufficient data for NMA, pairwise meta-analysis were conducted in RevMan. The GRADE approach was used to grade the evidence.

MAIN RESULTS

We included 12 RCTs involving approximately 1818 participants. Six were conducted exclusively among elderly people (either defined as 65 years or older or 70 years or older) with newly diagnosed glioblastoma, the other six reported data for an elderly subgroup among a broader age range of participants. Most participants were capable of self-care. Study quality was commonly undermined by lack of outcome assessor blinding and attrition. NMA was only possible for overall survival; other analyses were pair-wise meta-analyses or narrative syntheses. Seven trials contributed to the NMA for overall survival, with interventions including supportive care only (one trial arm); hypofractionated radiotherapy (RT40; four trial arms); standard radiotherapy (RT60; five trial arms); temozolomide (TMZ; three trial arms); chemoradiotherapy (CRT; three trial arms); bevacizumab with chemoradiotherapy (BEV_CRT; one trial arm); and bevacizumab with radiotherapy (BEV_RT). Compared with supportive care only, NMA evidence suggested that all treatments apart from BEV_RT prolonged survival to some extent. Overall survival High-certainty evidence shows that CRT prolongs overall survival (OS) compared with RT40 (hazard ratio (HR) 0.67, 95% confidence interval (CI) 0.56 to 0.80) and low-certainty evidence suggests that CRT may prolong overall survival compared with TMZ (TMZ versus CRT: HR 1.42, 95% CI 1.01 to 1.98). Low-certainty evidence also suggests that adding BEV to CRT may make little or no difference (BEV_CRT versus CRT: HR 0.83, 95% CrI 0.48 to 1.44). We could not compare the survival effects of CRT with different radiotherapy fractionation schedules (60 Gy/30 fractions and 40 Gy/15 fractions) due to a lack of data. When treatments were ranked according to their effects on OS, CRT ranked higher than TMZ, RT and supportive care only, with the latter ranked last. BEV plus RT was the only treatment for which there was no clear benefit in OS over supportive care only.   One trial comparing tumour treating fields (TTF) plus adjuvant chemotherapy (TTF_AC) with adjuvant chemotherapy alone could not be included in the NMA as participants were randomised after receiving concomitant chemoradiotherapy, not before. Findings from the trial suggest that the intervention probably improves overall survival in this selected patient population. We were unable to perform NMA for other outcomes due to insufficient data. Pairwise analyses were conducted for the following. Quality of life Moderate-certainty narrative evidence suggests that overall, there may be little difference in QoL between TMZ and RT, except for discomfort from communication deficits, which are probably more common with RT (1 study, 306 participants, P = 0.002). Data on QoL for other comparisons were sparse, partly due to high dropout rates, and the certainty of the evidence tended to be low or very low. Progression-free survival High-certainty evidence shows that CRT increases time to disease progression compared with RT40 (HR 0.50, 95% CI 0.41 to 0.61); moderate-certainty evidence suggests that RT60 probably increases time to disease progression compared with supportive care only (HR 0.28, 95% CI 0.17 to 0.46), and that BEV_RT probably increases time to disease progression compared with RT40 alone (HR 0.46, 95% CI 0.27 to 0.78). Evidence for other treatment comparisons was of low- or very low-certainty. Severe adverse events Moderate-certainty evidence suggests that TMZ probably increases the risk of grade 3+ thromboembolic events compared with RT60 (risk ratio (RR) 2.74, 95% CI 1.26 to 5.94; participants = 373; studies = 1) and also the risk of grade 3+ neutropenia, lymphopenia, and thrombocytopenia. Moderate-certainty evidence also suggests that CRT probably increases the risk of grade 3+ neutropenia, leucopenia and thrombocytopenia compared with hypofractionated RT alone. Adding BEV to CRT probably increases the risk of thromboembolism (RR 16.63, 95% CI 1.00 to 275.42; moderate-certainty evidence). Economic evidence There is a paucity of economic evidence regarding the management of newly diagnosed glioblastoma in the elderly. Only one economic evaluation on two short course radiotherapy regimen (25 Gy versus 40 Gy) was identified and its findings were considered unreliable.

AUTHORS' CONCLUSIONS

For elderly people with glioblastoma who are self-caring, evidence suggests that CRT prolongs survival compared with RT and may prolong overall survival compared with TMZ alone. For those undergoing RT or TMZ therapy, there is probably little difference in QoL overall. Systemic anti-cancer treatments TMZ and BEV carry a higher risk of severe haematological and thromboembolic events and CRT is probably associated with a higher risk of these events. Current evidence provides little justification for using BEV in elderly patients outside a clinical trial setting. Whilst the novel TTF device appears promising, evidence on QoL and tolerability is needed in an elderly population. QoL and economic assessments of CRT versus TMZ and RT are needed. More high-quality economic evaluations are needed, in which a broader scope of costs (both direct and indirect) and outcomes should be included.

Steroids use and survival in patients with glioblastoma multiforme: a pooled analysis

INTRODUCTION

Steroids are commonly used for managing brain edema in patients with glioblastoma multiforme (GBM), treated with surgery and concomitant temozolomide-based chemoradiotherapy (CTRT). The adverse effects of glucocorticoids include lymphopenia, hyperglycemia, and risk of infection. We report the results of a meta-analysis evaluating the effects of steroids on outcome when associated with the treatment of GBM.

METHODS

PubMed, the Cochrane Library, and Embase were searched from inception until September 2019 for observational or prospective studies reporting prognosis of adult patients with GBM and treated or not treated with steroids. Overall survival (OS) was the primary endpoint, and progression-free survival (PFS) was the secondary endpoint. The effect size was reported as hazard ratios (HRs) with a 95% confidence interval (CI), and an HR > 1 associated with the worst outcome in steroid users compared to non-users.

RESULTS

Twenty-two publications were retrieved from studies selected for a total of 8,752 patients. In the primary analysis (n = 22 studies reporting data), OS was reduced in GBM patients taking steroids during treatment (HR = 1.54, 95% CI 1.37-1.75; p < 0.01). Similarly, PFS was inferior in steroid users in n = 9 studies with data available (HR = 1.28, 95% CI 1.1-1.49; p < 0.01).

CONCLUSIONS

In patients with GBM and treated with RT and/or CT, association with steroids significantly reduces survival and PFS. Use of the lowest dose of glucocorticoids for the shortest period needed to achieve the treatment goals and prevention of steroid-associated complications are essential aims of treatment of this disease.

Optimal adjuvant therapy in elderly glioblastoma: results from a systematic review and network meta-analysis

BACKGROUND

There exists lack of consensus worldwide regarding the most optimal adjuvant therapy regimen in elderly patients with newly-diagnosed glioblastoma (GBM).

PURPOSE

To identify the most optimal adjuvant therapy regimen in elderly GBM patients through systematic review and network meta-analysis.

METHODS

Prospective trials randomly assigning elderly GBM patients post-operatively to any adjuvant therapy regimen were included. The primary outcome measure was overall survival. Numbers of events, patients at-risk, and censored patients for survival were estimated from Kaplan-Meier survival curves in the interval of 0-12 months. The total person-time at risk and the mortality × 100 person-months was also estimated. The relative ranking probability of each treatment and rankograms were used to estimate the hierarchy of each intervention in terms of overall survival. The mean rank values and the surface under the cumulative ranking (SUCRA) curves were also calculated.

RESULTS

A systematic literature search identified 1278 abstracts, that were screened to retrieve full-text manuscripts of potentially eligible articles. After detailed assessment, data from 1569 patients in 7 randomized controlled trials (RCTs) treated with one of following regimens was extracted and analyzed: normofractionated radiotherapy (RT) delivered over 5.5-6 weeks; moderately hypofractionated RT (2-3 weeks) either alone or in combination with temozolomide or bevacizumab; extremely hypofractionated RT (1-week); temozolomide monotherapy; and best supportive care alone. In terms of overall survival, moderately hypofractionated RT (3-weeks) with concurrent and adjuvant temozolomide emerged as the best and second-best adjuvant therapy option with 81% probability and 99.1% probability respectively. Using SUCRA, the surface area for moderately hypofractionated RT (3-weeks) with concurrent and adjuvant temozolomide reached almost 100%, confirming it as the best intervention. As expected, best supportive care alone was ranked as the worst treatment strategy.

CONCLUSION

Moderately hypofractionated RT (3-weeks) with concurrent and adjuvant temozolomide is the most optimal and preferred adjuvant therapeutic regimen in elderly GBM.

Progression-Free but No Overall Survival Benefit for Adult Patients with Bevacizumab Therapy for the Treatment of Newly Diagnosed Glioblastoma: A Systematic Review and Meta-Analysis

Glioblastoma (GBM) is the most common high-grade primary brain tumor in adults. Standard multi-modality treatment of glioblastoma with surgery, temozolomide chemotherapy, and radiation results in transient tumor control but inevitably gives way to disease progression. The need for additional therapeutic avenues for patients with GBM led to interest in anti-angiogenic therapies, and in particular, bevacizumab. We sought to determine the efficacy of bevacizumab as a treatment for newly diagnosed GBM. We conducted a literature search using the PubMed database and Google Scholar to identify randomized controlled trials (RCTs) since 2014 investigating the safety and efficacy of bevacizumab in the treatment of adult patients (18 years and older) with newly diagnosed GBM. Only Level Ι data that reported progression-free survival (PFS) and overall survival (OS) were included for analysis. Random effects meta-analyses on studies with newly diagnosed glioblastoma were conducted in R to estimate the pooled hazard ratio (HR) for PFS and OS. Six RCTs met requirements for meta-analysis, revealing a pooled estimate of PFS HR suggesting a 33% decreased risk of disease progression (HR 0.67, 95% CI, 0.58–0.78; p < 0.001) with bevacizumab therapy, but no effect on OS (HR = 1, 95% CI, 0.85–1.18; p = 0.97). A pooled estimate of the mean difference in OS months of −0.13 predicts little difference in time of survival between treatment groups (95% CI, −1.87–1.61). The pooled estimate for the mean difference in PFS months was 2.70 (95% CI, 1.89–3.50; p < 0.001). Meta-analysis shows that bevacizumab therapy is associated with a longer PFS in adult patients with newly diagnosed glioblastoma, but had an inconsistent effect on OS in this patient population.

Copy number profiling across glioblastoma populations has implications for clinical trial design

Background

Copy number alterations form prognostic molecular subtypes of glioblastoma with clear differences in median overall survival. In this study, we leverage molecular data from several glioblastoma cohorts to define the distribution of copy number subtypes across random cohorts as well as cohorts with selection biases for patients with inherently better outcome.

Methods

Copy number subtype frequency was established for 4 glioblastoma patient cohorts. Two randomly selected cohorts include The Cancer Genome Atlas (TCGA) and the German Glioma Network (GGN). Two more selective cohorts include the phase II trial ARTE in elderly patients with newly diagnosed glioblastoma and a multi-institutional cohort focused on paired resected initial/recurrent glioblastoma. The paired initial/recurrent cohort also had exome data available, which allowed for evaluation of multidimensional scaling analysis.

Results

Smaller selective glioblastoma cohorts are enriched for copy number subtypes that are associated with better survival, reflecting the selection of patients who do well enough to enter a clinical trial or who are deemed well enough to undergo resection at recurrence. Adding exome data to copy number data provides additional data reflective of outcome.

Conclusions

The overall outcome for diffuse glioma patients is predicted by DNA structure at initial tumor resection. Molecular signature shifts across glioblastoma populations reflect the inherent bias of patient selection toward longer survival in clinical trials. Therefore it may be important to include molecular profiling, including copy number, when enrolling patients for clinical trials in order to balance arms and extrapolate relevance to the general glioblastoma population.

Molecular targeted therapy of glioblastoma

Glioblastomas are intrinsic brain tumors thought to originate from neuroglial stem or progenitor cells. More than 90% of glioblastomas are isocitrate dehydrogenase (IDH)-wildtype tumors. Incidence increases with age, males are more often affected. Beyond rare instances of genetic predisposition and irradiation exposure, there are no known glioblastoma risk factors. Surgery as safely feasible followed by involved-field radiotherapy plus concomitant and maintenance temozolomide chemotherapy define the standard of care since 2005. Except for prolonged progression-free, but not overall survival afforded by the vascular endothelial growth factor antibody, bevacizumab, no pharmacological intervention has been demonstrated to alter the course of disease. Specifically, targeting cellular pathways frequently altered in glioblastoma, such as the phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR), the p53 and the retinoblastoma (RB) pathways, or epidermal growth factor receptor (EGFR) gene amplification or mutation, have failed to improve outcome, likely because of redundant compensatory mechanisms, insufficient target coverage related in part to the blood brain barrier, or poor tolerability and safety. Yet, uncommon glioblastoma subsets may exhibit specific vulnerabilities amenable to targeted interventions, including, but not limited to: high tumor mutational burden, BRAF mutation, neurotrophic tryrosine receptor kinase (NTRK) or fibroblast growth factor receptor (FGFR) gene fusions, and MET gene amplification or fusions. There is increasing interest in targeting not only the tumor cells, but also the microenvironment, including blood vessels, the monocyte/macrophage/microglia compartment, or T cells. Improved clinical trial designs using pharmacodynamic endpoints in enriched patient populations will be required to develop better treatments for glioblastoma.

Long-term neurocognitive and other side effects of radiotherapy, with or without chemotherapy, for glioma

BACKGROUND

Gliomas are brain tumours arising from glial cells with an annual incidence of 4 to 11 people per 100,000. In this review we focus on gliomas with low aggressive potential in the short term, i.e. low-grade gliomas. Most people with low-grade gliomas are treated with surgery and may receive radiotherapy thereafter. However, there is concern about the possible long-term effects of radiotherapy, especially on neurocognitive functioning.

OBJECTIVES

To evaluate the long-term neurocognitive and other side effects of radiotherapy (with or without chemotherapy) compared with no radiotherapy, or different types of radiotherapy, among people with glioma (where 'long-term' is defined as at least two years after diagnosis); and to write a brief economic commentary.

SEARCH METHODS

We searched the following databases on 16 February 2018 and updated the search on 14 November 2018: Cochrane Central Register of Controlled Trials (CENTRAL; 2018, Issue 11) in the Cochrane Library; MEDLINE via Ovid; and Embase via Ovid. We also searched clinical trial registries and relevant conference proceedings from 2014 to 2018 to identify ongoing and unpublished studies.

SELECTION CRITERIA

Randomised and non-randomised trials, and controlled before-and-after studies (CBAS). Participants were aged 16 years and older with cerebral glioma other than glioblastoma. We included studies where patients in at least one treatment arm received radiotherapy, with or without chemotherapy, and where neurocognitive outcomes were assessed two or more years after treatment.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data and assessed risk of bias. We assessed the certainty of findings using the GRADE approach.

MAIN RESULTS

The review includes nine studies: seven studies were of low-grade glioma and two were of grade 3 glioma. Altogether 2406 participants were involved but there was high sample attrition and outcome data were available for a minority of people at final study assessments. In seven of the nine studies, participants were recruited to randomised controlled trials (RCTs) in which longer-term follow-up was undertaken in a subset of people that had survived without disease progression. There was moderate to high risk of bias in studies due to lack of blinding and high attrition, and in two observational studies there was high risk of selection bias. Paucity of data and risk of bias meant that evidence was of low to very low certainty. We were unable to combine results in meta-analysis due to diversity in interventions and outcomes.The studies examined the following five comparisons.Radiotherapy versus no adjuvant treatmentTwo observational studies contributed data. At the 12-year follow-up in one study, the risk of cognitive impairment (defined as cognitive disability deficits in at least five of 18 neuropsychological tests) was greater in the radiotherapy group (risk ratio (RR) 1.95, 95% confidence interval (CI) 1.02 to 3.71; n = 65); at five to six years the difference between groups did not reach statistical significance (RR 1.38, 95% CI 0.92 to 2.06; n = 195). In the other study, one subject in the radiotherapy group had cognitive impairment (defined as significant deterioration in eight of 12 neuropsychological tests) at two years compared with none in the control group (very low certainty evidence).With regard to neurocognitive scores, in one study the radiotherapy group was reported to have had significantly worse mean scores on some tests compared with no radiotherapy; however, the raw data were only given for significant findings. In the second study, there were no clear differences in any of the various cognitive outcomes at two years (n = 31) and four years (n = 15) (very low certainty evidence).Radiotherapy versus chemotherapyOne RCT contributed data on cognitive impairment at up to three years with no clear difference between arms (RR 1.43, 95% CI 0.36 to 5.70, n = 117) (low-certainty evidence).High-dose radiotherapy versus low-dose radiotherapyOnly one of two studies reporting this comparison contributed data, and at two and five years there were no clear differences between high- and low-dose radiotherapy arms (very low certainty evidence).Conventional radiotherapy versus stereotactic conformal radiotherapyOne study involving younger people contributed limited data from the subgroup aged 16 to 25 years. The numbers of participants with neurocognitive impairment at five years after treatment were two out of 12 in the conventional arm versus none out of 11 in the stereotactic conformal radiotherapy arm (RR 4.62, 95% CI 0.25 to 86.72; n = 23; low-certainty evidence).Chemoradiotherapy versus radiotherapyTwo RCTs tested for cognitive impairment. One defined cognitive impairment as a decline of more than 3 points in MMSE score compared with baseline and reported data from 2-year (110 participants), 3-year (91 participants), and 5-year (57 participants) follow-up with no clear difference between the two arms at any time point. A second study did not report raw data but measured MMSE scores over five years in 126 participants at two years, 110 at three years, 69 at four years and 53 at five years. Authors concluded that there was no difference in MMSE scores between the two study arms (P = 0.4752) (low-certainty evidence).Two RCTs reported quality of life (QoL) outcomes for this comparison. One reported no differences in Brain-QoL scores between study arms over a 5-year follow-up period (P = 0.2767; no raw data were given and denominators were not stated). The other trial reported that the long-term results of health-related QoL showed no difference between the arms but did not give the raw data for overall HRQoL scores (low-certainty evidence).We found no comparative data on endocrine dysfunction; we planned to develop a brief economic commentary but found no relevant economic studies for inclusion.

AUTHORS' CONCLUSIONS

Radiotherapy for gliomas with a good prognosis may increase the risk of neurocognitive side effects in the long term; however the magnitude of the risk is uncertain. Evidence on long-term neurocognitive side effects associated with chemoradiotherapy is also uncertain. Neurocognitive assessment should be an integral part of long-term follow-up in trials involving radiotherapy for lower-grade gliomas to improve the certainty of evidence regarding long-term neurocognitive effects. Such trials should also assess other potential long-term effects, including endocrine dysfunction, and evaluate costs and cost effectiveness.