CCR 20th Anniversary Commentary: Bevacizumab in the Treatment of Glioblastoma--The Progress and the Limitations

Targeted therapies in patients with newly diagnosed glioblastoma-A systematic meta-analysis of randomized clinical trials

Glioblastoma (GB) is the most common malignant primary brain tumor in adults. The standard of care for newly diagnosed GB involves surgical resection followed by radiochemotherapy with temozolomide, with or without tumor-treating fields. In recent years, various efforts have been made to identify suitable molecularly targeted treatment options for malignant brain tumors. This meta-analysis provides an overview of recently published randomized controlled trials (RCTs) with and without molecular stratification, analyzing targeted agents in patients with newly diagnosed GB. The Cochrane Library, MEDLINE (Ovid), ClinicalTrials.gov, WHO's International Clinical Trials Registry Platform, and Google Scholar were searched for RCTs on targeted therapies in patients with newly diagnosed glioblastoma. Hazard ratios (HRs) for overall survival (OS) and progression-free survival (PFS) were extracted and pooled in a random-effects meta-analysis. Twelve RCTs (n = 3941 patients) involving protein kinase inhibitors, proteasome and histone deacetylase inhibitors, anti-angiogenic approaches and poly (ADP-ribose) polymerase (PARP) inhibitors were included in the meta-analysis. None of the targeted agents achieved a significant benefit with regard to OS (HR = 0.98 [95% confidence interval (CI) 0.86-1.11, P = .7731]). By comparison, targeted therapy showed a benefit for PFS (HR = 0.83 [95% CI 0.74-0.94, P = .0037]), especially for patients with an unmethylated O6-methylguanine-DNA-methyltransferase (MGMT) promoter (0.75 [95% CI 0.56-0.99, P = .0440]). Prolongation of PFS was largely driven by VEGF inhibition with bevacizumab (HR = 0.70 [95% CI 0.61-0.80, P = .0000]). VEGF inhibition with bevacizumab prolonged PFS in patients with newly diagnosed glioblastoma compared to standard care. However, no improvement in OS was observed with any of the targeted agents.

The TNF receptor family member Fn14 is highly expressed in recurrent glioblastoma and in GBM patient-derived xenografts with acquired temozolomide resistance

Background

Glioblastoma (GBM) is a difficult to treat brain cancer that nearly uniformly recurs, and recurrent tumors are largely therapy resistant. Our prior work has demonstrated an important role for the tumor necrosis factor-like weak inducer of apoptosis (TWEAK) receptor fibroblast growth factor-inducible 14 (Fn14) in GBM pathobiology. In this study, we investigated Fn14 expression in recurrent GBM and in the setting of temozolomide (TMZ) resistance.

Methods

Fn14 mRNA expression levels in nonneoplastic brain, primary (newly diagnosed) GBM, and recurrent GBM (post-chemotherapy and radiation) specimens were obtained from The Cancer Genome Atlas data portal. Immunohistochemistry was performed using nonneoplastic brain, patient-matched primary and recurrent GBM, and gliosarcoma (GSM) specimens to examine Fn14 protein levels. Western blot analysis was used to compare Fn14 expression in parental TMZ-sensitive or matched TMZ-resistant patient-derived xenografts (PDXs) established from primary or recurrent tumor samples. The migratory capacity of control and Fn14-depleted TMZ-resistant GBM cells was assessed using the transwell migration assay.

Results

We found that Fn14 is more highly expressed in recurrent GBM tumors than their matched primary GBM counterparts. Fn14 expression is also significantly elevated in GSM tumors. GBM PDX cells with acquired TMZ resistance have higher Fn14 levels and greater migratory capacity than their corresponding parental TMZ-sensitive cells, and the migratory difference is due, at least in part, to Fn14 expression in the TMZ-resistant cells.

Conclusions

This study demonstrates that the Fn14 gene is highly expressed in recurrent GBM, GSM, and TMZ-resistant GBM PDX tumors. These findings suggest that Fn14 may be a valuable therapeutic target or drug delivery portal for treatment of recurrent GBM and GSM patients.

Bevacizumab-containing regimen in relapsed/progressed brain tumors: a single-institution experience

AIM

The aim of the study is to assess tumor response, treatment-related toxicities, progression-free survival (PFS), and overall survival (OS) in patients with relapsed/refractory brain tumors treated with bevacizumab-containing regimen.

METHODS

Patients that had received I and II line treatments with or without megatherapy were included. Doses and schedule were as follows: bevacizumab (BVZ) 10 mg/kg i.v. with irinotecan (IRI) 150 mg/m² i.v. every 2 weeks ± temozolamide (TMZ) 200 mg/m² p.o. daily for 5 days every 4 weeks. TMZ was omitted in heavily pretreated cases.

RESULTS

Between 2013 and 2018, 12 patients (3F/9M), median age 161 months (range 66-348), affected with medulloblastoma (n 7), or low-grade glioma (n 2), or high-grade glioma (n 3), received BVZ/IRI association (median courses 20, range 4-67); 3 of them continued single-agent BVZ (median courses 23, range 8-39). TMZ (median courses 8, range 2-26) was administered in eight patients and then stopped in three of them because of myelotoxicity or lack of compliance. Treatment was well tolerated. After 3 months, two complete responses, two partial responses, seven stable diseases, and one progressive disease were observed. Nine cases experienced an improvement in neurological symptoms. Median time to progression was 11 months (95% confidence interval, 4-18 months). Six-month and 2-year PFS were 75% and 42%, respectively. The OS is 33%; interestingly, two cases (one medulloblastoma and one high-grade glioma) are progression-free off-therapy since 30 and 48 months, respectively.

CONCLUSIONS

BVZ/IRI association ± TMZ showed encouraging therapeutic activity and low toxicity in this series of relapsed/refractory brain tumors.

Sensitization of glioblastoma tumor micro-environment to chemo- and immunotherapy by Galectin-1 intranasal knock-down strategy

In this study, we evaluated the consequences of reducing Galectin-1 (Gal-1) in the tumor micro-environment (TME) of glioblastoma multiforme (GBM), via nose-to-brain transport. Gal-1 is overexpressed in GBM and drives chemo- and immunotherapy resistance. To promote nose-to-brain transport, we designed siRNA targeting Gal-1 (siGal-1) loaded chitosan nanoparticles that silence Gal-1 in the TME. Intranasal siGal-1 delivery induces a remarkable switch in the TME composition, with reduced myeloid suppressor cells and regulatory T cells, and increased CD4+ and CD8+ T cells. Gal-1 knock-down reduces macrophages’ polarization switch from M1 (pro-inflammatory) to M2 (anti-inflammatory) during GBM progression. These changes are accompanied by normalization of the tumor vasculature and increased survival for tumor bearing mice. The combination of siGal-1 treatment with temozolomide or immunotherapy (dendritic cell vaccination and PD-1 blocking) displays synergistic effects, increasing the survival of tumor bearing mice. Moreover, we could confirm the role of Gal-1 on lymphocytes in GBM patients by matching the Gal-1 expression and their T cell signatures. These findings indicate that intranasal siGal-1 nanoparticle delivery could be a valuable adjuvant treatment to increase the efficiency of immune-checkpoint blockade and chemotherapy.