The Prognosis of Anti-Angiogenesis Treatments Combined with Standard Therapy for Newly Diagnosed Glioblastoma: A Meta-Analysis of Randomized Controlled Trials

Efficacy of Anti-VEGF Drugs Based Combination Therapies in Recurrent Glioblastoma: Systematic Review and Meta-Analysis

BACKGROUND

Recurrent glioblastoma multiforme (rGBM) has a grim prognosis, with current therapies offering no survival benefit. Several combination therapies involving anti-VEGF agents have been studied with mixed results.

METHODS

A systematic search was performed using five electronic databases: PubMed, Scopus, ISI, Embase, and the Cochrane Library, without language limitations. The primary outcome of interest was progression-free survival (PFS). Secondary outcomes were overall survival (OS), objective response ratio (ORR), and grade ≥ 3 adverse events. Estimates for PFS and OS were calculated as random effects hazard ratio (HR) with 95% confidence intervals (CIs) using the generic inverse variance method. Estimates for ORR and grade ≥ 3 adverse events were calculated using a random-effects risk ratio (RR) with 95% confidence intervals (CIs) using the Mantel-Haenszel method.

RESULTS

Thirteen studies met the inclusion criteria and a total of 1994 patients were included in the analysis. There was no statistically significant improvement in PFS (HR 0.84; 95% CI (0.68, 1.03); I2=81%), OS (HR 0.99; 95% CI (0.88, 1.12); I2=0%), and ORR (RR 1.36; 95% CI (0.96, 1.92); I2=61%) in the combination therapy group when compared to the control group. Significantly higher grade ≥ 3 adverse events (RR 1.30; 95% CI (1.14, 1.48); I2=47%) were seen in the combination therapy when compared to the control group.

CONCLUSION

Our analysis showed that the use of combination therapy with anti-VEGF agents did not offer any benefit in PFS, OS, or ORR. In contrast, it had significantly higher grade 3-5 adverse events. Further studies are needed to identify effective therapies in rGBM that can improve survival.

Downregulation of Astrocyte Elevated Gene-1 Expression Combined with All-Trans Retinoic Acid Inhibits Development of Vasculogenic Mimicry and Angiogenesis in Glioma

OBJECTIVE

This study aimed to investigate the effects of downregulating astrocyte elevated gene-1 (AEG-1) expression combined with all-trans retinoic acid (ATRA) on vasculogenic mimicry (VM) formation and angiogenesis in glioma.

METHODS

U87 glioma cells were transfected with AEG-1 shRNA lentiviral vectors (U87-siAEG-1) and incubated in a medium containing 20 µmol/L ATRA. Matrigel-based tube formation assay was performed to evaluate VM formation, and the cell counting kit-8 (CCK-8) assay was used to analyze the proliferation of glioma cells in vitro. Reverse transcription-quantitative polymerase chain reaction and Western blot analysis were used to investigate the mRNA and protein expression of related genes, respectively. Glioma xenograft models were generated via subcutaneous implantation of glioma cells in nude mice. Tumor-bearing mice received an intraperitoneal injection of ATRA (10 mg/kg per day). Immunohistochemistry was used to evaluate the expression of related genes and the microvessel density (MVD) in glioma xenograft models. CD34/periodic acid-Schiff double staining was performed to detect VM channels in vivo. The volume and weight of tumors were measured, and a tumor growth curve was drawn to evaluate tumor growth.

RESULTS

A combination of ATRA intervention and downregulation of AEG-1 expression significantly inhibited the proliferation of glioma cells in vitro and glioma VM formation in vitro and in vivo. It also significantly decreased MVD and inhibited tumor growth. Further, the expression levels of matrix metalloproteinase (MMP)-2, MMP-9, vascular endothelial-cadherin (VE-cadherin), and vascular endothelial growth factor (VEGF) in glioma significantly decreased in vivo and in vivo.

CONCLUSION

Hence, a combinatorial approach might be effective in treating glioma through regulating MMP-2, MMP-9, VEGF, and VE-cadherin expression.

Efficacy and safety of bevacizumab in the treatment of adult gliomas: a systematic review and meta-analysis

OBJECTIVE

To assess the efficacy and safety of bevacizumab (BEV) in patients with glioma.

DESIGN

Systematic review and meta-analysis.

PARTICIPANTS

Adults aged 18 years and above, whose histology was confirmed to be malignant glioma.

PRIMARY AND SECONDARY OUTCOME MEASURES

The main indicators included progression-free survival (PFS) rate and overall survival (OS) rate, and the secondary indicators were adverse reactions.

RESULTS

A total of 11 clinical centre trials were included in this study for meta-analysis, including 2392 patients. The results of the meta-analysis showed that the median PFS rate of the BEV group was significantly higher than that of the non-BEV group (p<0.00001). When comparing PFS between two groups, we found that the PFS in the BEV group was higher than that in the non-BEV group at 6 months (OR 3.31, 95% CI 2.74 to 4.00, p<0.00001), 12 months (OR 2.05, 95% CI 1.70 to 2.49, p<0.00001) and 18 months (OR 1.31, 95% CI 1.02 to 1.69, p=0.03). But at 24 months (OR 0.83, 95% CI 0.50 to 1.37, p=0.47), there was no significant difference between the two groups. At 30 months (OR 0.62, 95% CI 0.39 to 0.97, p=0.04), the PFS of the BEV group was lower than that of the non-BEV group. Moreover, The results showed that BEV had no significant effect on improving OS, but the adverse reaction in BEV group was significantly higher than that in non-BEV group.

CONCLUSION

The evidence suggests that BEV can significantly prolong the PFS of patients with glioma within 18 months and shorten the PFS of patients after 30 months. This limitation may be related to the subgroup of patients, the change of recurrence mode, the optimal dose of drug, the increase of hypoxia, the enhancement of invasiveness and so on. Therefore, it is necessary to carry out more samples and higher quality large-scale research in the future.

Cost-Effectiveness of Low-Field Intraoperative Magnetic Resonance in Glioma Surgery

Object

Low-field intraoperative magnetic resonance (LF-iMR) has demonstrated a slight increase in the extent of resection of intra-axial tumors while preserving patient`s neurological outcomes. However, whether this improvement is cost-effective or not is still matter of controversy. In this clinical investigation we sought to evaluate the cost-effectiveness of the implementation of a LF-iMR in glioma surgery.

Methods

Patients undergoing LF-iMR guided glioma surgery with gross total resection (GTR) intention were prospectively collected and compared to an historical cohort operated without this technology. Socio-demographic and clinical variables (pre and postoperative KPS; histopathological classification; Extent of resection; postoperative complications; need of re-intervention within the first year and 1-year postoperative survival) were collected and analyzed. Effectiveness variables were assessed in both groups: Postoperative Karnofsky performance status scale (pKPS); overall survival (OS); Progression-free survival (PFS); and a variable accounting for the number of patients with a greater than subtotal resection and same or higher postoperative KPS (R-KPS). All preoperative, procedural and postoperative costs linked to the treatment were considered for the cost-effectiveness analysis (diagnostic procedures, prosthesis, operating time, hospitalization, consumables, LF-iMR device, etc). Deterministic and probabilistic simulations were conducted to evaluate the consistency of our analysis.

Results

50 patients were operated with LF-iMR assistance, while 146 belonged to the control group. GTR rate, pKPS, R-KPS, PFS, and 1-year OS were respectively 13,8% (not significative), 7 points (p < 0.05), 17% (p < 0.05), 38 days (p < 0.05), and 3.7% (not significative) higher in the intervention group. Cost-effectiveness analysis showed a mean incremental cost per patient of 789 € in the intervention group. Incremental cost-effectiveness ratios were 111 € per additional point of pKPS, 21 € per additional day free of progression, and 46 € per additional percentage point of R-KPS.

Conclusion

Glioma patients operated under LF-iMR guidance experience a better functional outcome, higher resection rates, less complications, better PFS rates but similar life expectancy compared to conventional techniques. In terms of efficiency, LF-iMR is very close to be a dominant technology in terms of R-KPS, PFS and pKPS.

Comparative efficacy of antiangiogenic treatment for newly diagnosed glioblastoma: A protocol for systematic review and network meta-analysis

BACKGROUND

Glioblastoma is the most common malignant primary brain tumor which has highly expressed vascular endothelial growth factor. To date, various antiangiogenic drugs have been investigated in clinical trials but with no overall conclusion, especially for newly diagnosed glioblastoma (nGBM). In this study, Bayesian network meta-analysis will be used to conduct a comprehensive analysis of the results of different clinical trials, and assess the efficacy of different antiangiogenic drugs on nGBM.

METHODS

In order to find more comprehensive information about the application of antiangiogenic drugs in nGBM patients, we searched the MEDLINE, EMBASE, Web of Science, and Cochrane Central Register of Controlled Trials for relevant randomized controlled trials. We also reviewed their reference lists to avoid omissions. Cochrane risk of bias tool (V.1.4.3) and Stata (V.15.0) will be used to assess the methodological quality of this review.

RESULTS

This study will provide reliable evidence for different antiangiogenic therapies in nGBM patients.

CONCLUSION

We will evaluate the relative effectiveness of different antiangiogenic drugs and rank each intervention in nGBM patients through prognosis to provide decision-making reference on which method to choose for clinicians.

PROTOCOL REGISTRATION NUMBER

CRD42019146537.

The Role of Kinase Signaling in Resistance to Bevacizumab Therapy for Glioblastoma Multiforme

Glioblastoma multiforme (GBM) is the most malignant primary brain tumor and is characterized by vascular hyperplasia, necrosis, and high cell proliferation. Despite current standard therapies, including surgical resection and chemoradiotherapy, GBM patients survive for only about 15 months after diagnosis. Recently, the U.S. Food and Drug Administration (FDA) has approved an antiangiogenesis medication for recurrent GBM-bevacizumab-which has improved progression-free survival in GBM patients. Although bevacizumab has resulted in significant early clinical benefit, it inescapably predisposes tumor to relapse that can be represented as an infiltrative phenotype. Fundamentally, bevacizumab antagonizes the vascular endothelial growth factor A (VEGF_A), which is consistently released on both endothelial cells (ECs) and GBM cells. Actually, VEGF_A inhibition on the ECs leads to the suppression of vascular progression, permeability, and the vasogenic edema. However, the consequence of the VEGF_A pathway blockage on the GBM cells remains controversial. Nevertheless, a piece of evidence supports the relationship between bevacizumab application and compensatory activation of kinase signaling within GBM cells, leading to a tumor cell invasion known as the main mechanism of bevacizumab-induced tumor resistance. A complete understanding of kinase responses associated with tumor invasion in bevacizumab-resistant GBMs offers new therapeutic opportunities. Thus, this study aimed at presenting a brief overview of preclinical and clinical data of the tumor invasion and resistance induced by bevacizumab administration in GBMs, with a focus on the kinase responses during treatment. The novel therapeutic strategies to overcome this resistance by targeting protein kinases have also been summarized.

Bevacizumab combined with chemotherapy vs single-agent therapy in recurrent glioblastoma: evidence from randomized controlled trials

Background

Recent studies showed inconsistent results of bevacizumab combined with chemotherapy vs single-agent therapy in terms of their safety and efficacy for the treatment of recurrent glioblastoma. Therefore, we performed a meta-analysis to explore the value of bevacizumab combined with chemotherapy and single-agent therapy in recurrent glioblastoma treatment.

Methods

Databases such as MEDLINE, Embase, and Cochrane Library were searched for randomized controlled trials (RCTs) related to the topic of bevacizumab combined with chemotherapy and single-agent therapy as treatments for recurrent glioblastoma from January 1980 to April 2018. Subsequent articles were then sorted, evaluated, and analyzed.

Results

We pooled 1,169 patient cases from seven RCTs. Bevacizumab combined with chemotherapy showed a significantly improved progression-free survival (PFS) (HR=0.65; 95% CI 0.57-0.74; P<0.001) compared to single-agent therapy. In addition, the overall survival (OS) rate showed insignificant differences between the two groups (HR=0.96; 95% CI 0.83-1.12; P=0.622). Simultaneously, we found that bevacizumab combined with chemotherapy had a higher objective response rate (ORR) (OR=2.10; 95% CI 1.32-3.33; P=0.002), but also higher incidence of adverse events (AEs) (OR=1.85; 95% CI 1.26-2.71; P=0.002). However, in subgroup analysis, we found that AEs showed insignificant differences between the two treatment methods when bevacizumab was used as the single-agent therapy subgroup (P=0.058). In addition, in the subgroup with low corticosteroid use rate at baseline (N<50%), ORR (P=0.108) and AEs (P=0.134) showed insignificant differences between the two groups.

Conclusion

Bevacizumab combined with chemotherapy can significantly improve PFS and ORR, but did not prolong OS in these studies, and can even lead to higher odds of AEs. In addition, bevacizumab may play a dominant role and corticosteroid may be an unfavorable factor in the combination therapy of recurrent glioblastoma.

Targeting NRASQ61K mutant delays tumor growth and angiogenesis in non-small cell lung cancer

Tumor cells require vascular supply for their growth, and they express proangiogenic growth factors that promote the formation of vascular networks. Many oncogenic mutations that may potentially lead to tumor angiogenesis have been identified. Somatic mutations in the small GTPase NRAS are the most common activating lesions found in human cancer and are generally associated with poor response to standard therapies. However, the mechanisms by which NRAS mutations affect tumor angiogenesis are largely unknown. Therefore, we investigated the role of NRAS^Q61K oncogene in tumor angiogenesis and analyzed tumors harboring NRAS^Q61K for potential sensitivity to a kinase inhibitor. Knock-in of the NRAS^Q61K allele in human normal epithelial cells triggered the angiogenic response in these cells. In cancer cells harboring oncogenic NRAS, a mitogen-activated protein kinase (MEK) inhibitor down-regulated the extracellular regulated protein kinase (ERK) pathway and inhibited the expression of proangiogenic molecules. In tumor xenografts harboring the NRAS^Q61K, the MEK inhibitor extensively modified tumor growth, causing abrogation of angiogenesis. Overall, our results provide a functional link between oncogenic NRAS and angiogenesis, and imply that tumor vasculature could be indirectly altered by targeting a genetic lesion on which cancer cells are dependent.