Regorafenib compared with lomustine in patients with relapsed glioblastoma (REGOMA): a multicentre, open-label, randomised, controlled, phase 2 trial

An analysis of prognostic risk and immunotherapy response of glioblastoma patients based on single-cell landscape and nitrogen metabolism

Glioblastoma (GBM) is a highly invasive brain tumor of astrocytic origin. Nitrogen metabolism plays an instrumental role in the growth and progression of various tumors, including GBM. This study intended to mine nitrogen metabolism-related biomarkers for GBM-related research of prognosis and immunotherapy. Through single-cell data analysis of GBM, we identified four cell types (Astrocytes, Macrophages, Fibroblasts, and Endothelial cells). We calculated the nitrogen metabolism scores and conducted trajectory analysis for the most abundant cells, Astrocytes, revealing 6 differentiation directions of Astrocytes, which included the main differentiation direction from cells with low nitrogen metabolism scores to cells with high nitrogen metabolism scores. Furthermore, based on the differentially expressed genes (DEGs) with high/low nitrogen metabolism scores, we constructed a 7-gene prognostic model by utilizing regression analysis. qRT-PCR analysis showed that IGFBP2, CHPF, CTSZ, UPP1, TCF12, ZBTB20 and RBP1 were all significantly up-regulated in the GBM cells. Through differential analysis, a protein-protein interaction (PPI) network, and enrichment analyses, we identified and analyzed the DEGs in the high RiskScore subgroup, revealing complex interactions among DEGs, which were mainly related to pathways such as TNF signaling pathway and NF-κB signaling pathway. By leveraging univariate analysis, survival-related genes were selected from the nitrogen metabolism-related gene sets. Clustering, survival, immune, and mutation analyses manifested that the collected nitrogen metabolism-related genes had good classification performance, presenting notable differences in survival rates, immune levels, gene mutations, and sensitivity to drugs between cluster1 and cluster2. In conclusion, the project investigated the prognosis and classification value of nitrogen metabolism-related genes in GBM from multiple perspectives, predicting the sensitivity of different subtypes of patients to immunotherapy response and drug sensitivity. These findings are expected to show new research directions for further exploration in these fields.

Circular RNAs in glioma progression: Fundamental mechanisms and therapeutic potential: A review

Gliomas are the most common primary malignant brain tumors, characterized by aggressive invasion, limited therapeutic options, and poor prognosis. Despite advances in surgery, radiotherapy, and chemotherapy, the median survival of glioma patients remains disappointingly low. Therefore, identifying glioma-associated therapeutic targets and biomarkers is of significant clinical importance. Circular RNAs (circRNAs) are a class of naturally occurring long non-coding RNAs (lncRNAs), notable for their stability and evolutionary conservation. Increasing evidence indicates that circRNA expression is dysregulated in gliomas compared to adjacent non-tumor tissues and contributes to the regulation of glioma-related biological processes. Furthermore, numerous circRNAs function as oncogenes or tumor suppressors, mediating glioma initiation, progression, and resistance to temozolomide (TMZ). Mechanistically, circRNAs regulate glioma biology through diverse pathways, including acting as miRNA sponges, binding RNA-binding proteins (RBPs), modulating transcription, and even encoding functional peptides. These features highlight the potential of circRNAs as diagnostic and prognostic biomarkers, as well as therapeutic targets for glioma. This review summarizes the dysregulation and functions of circRNAs in glioma and explores key mechanisms through which they mediate tumor progression, including DNA damage repair, programmed cell death (PCD), angiogenesis, and metabolic reprogramming. Our aim is to provide a comprehensive perspective on the multifaceted roles of circRNAs in glioma and to highlight their potential for translational application in targeted therapy.

Epigenetic regulation of histone modifications in glioblastoma: recent advances and therapeutic insights

Glioblastoma (GBM) is the most common primary malignant brain tumor, characterized by its aggressive behavior, limited treatment options, and poor prognosis. Despite advances in surgery, radiotherapy, and chemotherapy, the median survival of GBM patients remains disappointingly short. Recent studies have underscored the critical role of histone modifications in GBM malignant progression and therapy resistance. Histones, protein components of chromatin, undergo various modifications, including acetylation and methylation. These modifications significantly affect gene expression, thereby promoting tumorigenesis and resistance to therapy. Targeting histone modifications has emerged as a promising therapeutic approach. Numerous pre-clinical studies have evaluated histone modification agents in GBM, including histone deacetylase inhibitors and histone methyltransferase inhibitors. These studies demonstrate that modulating histone modifications can alter gene expression patterns, inhibit tumor growth, induce apoptosis, and sensitize tumor cells to conventional treatments. Some agents have advanced to clinical trials, aiming to translate preclinical efficacy into clinical benefit. However, clinical outcomes remain suboptimal, as many agents fail to significantly improve GBM patient prognosis. These challenges are attributed to the complexity of histone modification networks and the adaptive responses of the tumor microenvironment. This review provides a comprehensive overview of epigenetic regulation mechanisms involving histone modifications in GBM, covering their roles in tumor development, tumor microenvironment remodeling, and therapeutic resistance. Additionally, the review discusses current clinical trials targeting histone modifications in GBM, highlighting successes, limitations, and future perspectives.

Genome-wide CRISPR-Cas9 screens identify BCL family members as modulators of response to regorafenib in experimental glioma

BACKGROUND

Registered systemic treatment options for glioblastoma patients are limited. The phase II REGOMA trial suggested an improvement of median overall survival in progressive glioblastoma by the multi-tyrosine kinase inhibitor regorafenib. This has not been confirmed by GBM AGILE. So far, regorafenib has been administered as monotherapy or as an addition to standard of care in newly diagnosed glioblastoma. Rational combination therapies involving regorafenib might be a reasonable strategy. Here, we aimed at identifying functionally instructed combination therapies involving regorafenib.

METHODS

We applied a genome-wide CRISPR-Cas9-based functional genomics target discovery approach using activation and knockout screens followed by genetic, pharmacological, functional validations. Regorafenib-induced molecular alterations were assessed by RNA sequencing and DigiWest. We investigated selected functionally instructed combination therapies in three orthotopic glioma mouse models in vivo (syngeneic SMA560/VM/Dk model and two xenograft models) and performed immunohistochemistry of post-treatment brains.

RESULTS

We identified potential modifiers of regorafenib response, including BCL2, BCL2L1, ITGB3, FOXC1, SERAC1, ARAF, and PLCE1. The combination of regorafenib with Bcl-2/Bcl-xL inhibition was superior to both monotherapies alone in vitro, ex vivo, and in vivo. We identified regorafenib-induced regulations of the Bcl-2 downstream target chemokine receptor 1 (CCR1) as one potential underlying molecular mediator. Furthermore, regorafenib led to changes in the myeloid compartment of the glioma-associated microenvironment.

CONCLUSIONS

This preclinical study uses a functional genomics-based target discovery approach with subsequent validations involving regorafenib. It serves as a biological rationale for clinical translation. Particularly, an investigation of the combination of regorafenib plus navitoclax within a clinical trial is warranted.

Targeting Glioma Stem Cells: Therapeutic Opportunities and Challenges

Glioblastoma (GBM), or grade 4 glioma, is the most common and aggressive primary brain tumor in adults with a median survival of 15 months. Increasing evidence suggests that GBM's aggressiveness, invasiveness, and therapy resistance are driven by glioma stem cells (GSCs), a subpopulation of tumor cells that share molecular and functional characteristics with neural stem cells (NSCs). GSCs are heterogeneous and highly plastic. They evade conventional treatments by shifting their state and entering in quiescence, where they become metabolically inactive and resistant to radiotherapy and chemotherapy. GSCs can exit quiescence and be reactivated to divide into highly proliferative tumor cells which contributes to recurrence. Understanding the molecular mechanisms regulating the biology of GSCs, their plasticity, and the switch between quiescence and mitotic activity is essential to shape new therapeutic strategies. This review examines the latest evidence on GSC biology, their role in glioblastoma progression and recurrence, emerging therapeutic approaches aimed at disrupting their proliferation and survival, and the mechanisms underlying their resistance to therapy.

Kinase-Targeted Therapies for Glioblastoma

Protein phosphorylation and dephosphorylation are key mechanisms that regulate cellular activities. The addition or removal of phosphate groups by specific enzymes, known as kinases and phosphatases, activates or inhibits many enzymes and receptors involved in various cell signaling pathways. Dysregulated activity of these enzymes is associated with various diseases, predominantly cancers. Synthetic and natural single- and multiple-kinase inhibitors are currently being used as targeted therapies for different tumors, including glioblastoma. Glioblastoma IDH-wild-type is the most aggressive brain tumor in adults, with a median overall survival of 15 months. The great majority of glioblastoma patients present mutations in receptor tyrosine kinase (RTK) signaling pathways responsible for tumor initiation and/or progression. Despite this, the multi-kinase inhibitor regorafenib has only recently been approved for glioblastoma patients in some countries. In this review, we analyze the history of kinase inhibitor drugs in glioblastoma therapy.

TRAF7 knockdown induces cellular senescence and synergizes with lomustine to inhibit glioma progression and recurrence

BACKGROUND

The progression and recurrence are the fatal prognostic factors in glioma patients. However, the therapeutic role and potential mechanism of TRAF7 in glioma patients remain largely unknown.

METHODS

TRAF7 RNA-seq was analysed with the TCGA and CGGA databases between glioma tissues and normal brain tissues. The expression of TRAF7, cellular senescence and cell cycle arrest pathways in glioma tissues and cell lines was detected by real-time quantitative PCR (RT-qPCR), western blotting and immunohistochemistry. The interaction between TRAF7 and KLF4 was determined by Co-immunoprecipitation (Co-IP) assays. The functions of TRAF7 combined with lomustine in glioma were assessed by both in vitro, in vivo and patient-derived primary and recurrent glioma stem cell (GSC) assays.

RESULTS

High TRAF7 expression is closely associated with a higher recurrence rate and poorer overall survival (OS). In vitro, TRAF7 knockdown significantly inhibits glioma cell proliferation, invasion, and migration. RNA-seq analysis revealed that TRAF7 inhibition activates pathways related to cellular senescence and cell cycle arrest. In both in vitro and patient-derived GSC assays, the combination of sh-TRAF7 and lomustine enhanced therapeutic efficacy by inducing senescence and G0/G1 cell cycle arrest, surpassing the effects of lomustine or TRAF7 inhibition alone. Mechanistically, TRAF7 interacts with KLF4, and a rescue assay demonstrated that KLF4 overexpression could reverse the effects of TRAF7 depletion on proliferation and cellular senescence. In vivo, TRAF7 knockdown combined with lomustine treatment effectively suppressed glioma growth.

CONCLUSION

TRAF7 could be used as a predictive biomarker and the potential therapeutic target among National Comprehensive Cancer Network (NCCN) treatment guidelines in the progression and recurrence of glioma. Lomustine, regulating cellular senescence and cell cycle could be the priority choice in glioma patients with high-level TRAF7 expression.

Canadian Expert Consensus Recommendations for the Diagnosis and Management of Glioblastoma: Results of a Delphi Study

Glioblastoma is the most common and aggressive malignant brain tumor in adults, with an increasing incidence and a poor prognosis. Current challenges in glioblastoma management include rapid tumor growth, limited treatment effectiveness, high recurrence rates, and a significant impact on patients' quality of life. Given the complexity of glioblastoma care and recent advancements in diagnostic and treatment modalities, updated guidelines are needed in Canada. This Delphi study aimed to develop Canadian consensus recommendations for the diagnosis, classification, and management of newly diagnosed and recurrent glioblastoma. A multidisciplinary panel of 14 Canadian experts in glioblastoma care was convened, and a comprehensive literature review was conducted to synthesize evidence and formulate initial recommendations. Consensus was achieved through three Delphi rounds, in which panelists rated their agreement with recommendation statements on a five-point Likert scale. Statements with ≥75% agreement were accepted, and others were revised for re-voting. Final recommendations were formulated based on the consensus level, strength of evidence, clinical expertise, and consideration of the Canadian healthcare context. These recommendations aim to standardize glioblastoma diagnosis and classification across Canada, provide evidence-based guidance for optimal treatment selection, integrate novel therapies, and enhance the overall quality of care for glioblastoma patients.

A Radiologist's Guide to IDH-Wildtype Glioblastoma for Efficient Communication With Clinicians: Part II-Essential Information on Post-Treatment Imaging

Owing to recent advancements in various postoperative treatment modalities, such as radiation, chemotherapy, antiangiogenic treatment, and immunotherapy, the radiological and clinical assessment of patients with isocitrate dehydrogenase-wildtype glioblastoma using post-treatment imaging has become increasingly challenging. This review highlights the challenges in differentiating treatment-related changes such as pseudoprogression, radiation necrosis, and pseudoresponse from true tumor progression and aims to serve as a guideline for efficient communication with clinicians for optimal management of patients with post-treatment imaging.

Understanding Neovascularization in Glioblastoma: Insights from the Current Literature

Glioblastomas (GBMs), among the most aggressive and resilient brain tumors, characteristically exhibit high angiogenic potential, leading to the formation of a dense yet aberrant vasculature, both morphologically and functionally. With these premises, numerous expectations were initially placed on anti-angiogenic therapies, soon dashed by their limited efficacy in concretely improving patient outcomes. Neovascularization in GBM soon emerged as a complex, dynamic, and heterogeneous process, hard to manage with the classical standard of care. Growing evidence has revealed the existence of numerous non-canonical strategies of angiogenesis, variously exploited by GBM to meet its ever-increasing metabolic demand and differently involved in tumor progression, recurrence, and escape from treatments. In this review, we provide an accurate description of each neovascularization mode encountered in GBM tumors to date, highlighting the molecular players and signaling cascades primarily involved. We also detail the key architectural and functional aspects characteristic of the GBM vascular compartment because of an intricate crosstalk between the different angiogenic networks. Additionally, we explore the repertoire of emerging therapies against GBM that are currently under study, concluding with a question: faced with such a challenging scenario, could combined therapies, tailored to the patient's genetic signatures, represent an effective game changer?

Response to anti-angiogenic therapy is affected by AIMP protein family activity in glioblastoma and lower-grade gliomas

Background

Glioblastoma (GBM) is a highly vascularized, heterogeneous tumor, yet anti-angiogenic therapies have yielded limited survival benefits. The lack of validated predictive biomarkers for treatment response stratification remains a major challenge. Aminoacyl tRNA synthetase complex-interacting multicomplex proteins (AIMPs) 1/2/3 have been implicated in CNS diseases, but their roles in gliomas remain unexplored. We investigated their association with angiogenesis and their significance as predictive biomarkers for anti-angiogenic treatment response.

Methods

In this multi-cohort retrospective study we analyzed glioma samples from TCGA, CGGA, Rembrandt, Gravendeel, BELOB and REGOMA trials, and four single-cell transcriptomic datasets. Multi-omic analyses incorporated transcriptomic, epigenetic, and proteomic data. Kaplan-Meier and Cox proportional hazards models were used to assess the prognostic value of AIMPs in heterogeneous and homogeneous treatment-groups. Using single-cell transcriptomics, we explored spatial and cell-type-specific AIMP2 expression in GBM.

Results

AIMP1/2/3 expressions correlated significantly with angiogenesis across TCGA cancers. In gliomas, AIMPs were upregulated in tumor vs. normal tissues, higher- vs. lower-grade gliomas, and recurrent vs. primary tumors (p<0.05). Upon retrospective analysis of two clinical trials assessing different anti-angiogenic drugs, we found that high-AIMP2 subgroups had improved response to therapies in GBM (REGOMA: HR 4.75 [1.96-11.5], p<0.001; BELOB: HR 2.3 [1.17-4.49], p=0.015). AIMP2-cg04317940 methylation emerged as a clinically applicable stratification marker. Single-cell analysis revealed homogeneous AIMP2 expression in tumor tissues, particularly in AC-like cells, suggesting a mechanistic link to tumor angiogenesis.

Conclusions

These findings provide novel insights into the role of AIMPs in angiogenesis, offering improved patient stratification and therapeutic outcomes in recurrent GBM.

Identifying new therapeutics for focused ultrasound-enhanced drug delivery in the management of glioblastoma

Glioblastoma, a grade IV astrocytoma, typically has a poor prognosis, with most patients succumbing within eighteen months of diagnosis and few experiencing long-term survival. Focused ultrasound, an emerging localized therapy, has shown promising results in early-phase studies for glioblastoma by improving the uptake of temozolomide and carboplatin. The blood-brain barrier is critical to homeostasis by regulating the movement of substances between the bloodstream and the central nervous system. While this barrier helps prevent infections from bloodborne pathogens, it also hinders the delivery of cancer therapies to gliomas. Combining focused ultrasound with circulating microbubbles enhances local blood-brain barrier permeability, facilitating the intratumoral uptake of systemic cancer therapies. The purpose of this study was to identify promising new therapeutics in the treatment of glioblastoma for localized drug delivery via focused ultrasound. This review provides an overview of the current standard of care for newly diagnosed and recurrent glioblastoma, identifies current therapies indicated for the treatment, discusses key aspects of microbubble resonators, describes focused ultrasound devices under evaluation in human trials, and concludes with a perspective of emerging therapeutics for future studies.

Overcoming cancer therapy resistance: From drug innovation to therapeutics

One of the major limitations of cancer therapy is the emergence of drug resistance. This review amis to provide a focused analysis of the multifactorial mechanisms underlying therapy resistance,with an emphasis on actionable insights for developing novel therapeutic strategies. It concisely outlines key factors contributing to therapy resistance, including drug delivery barriers, cancer stem cells (CSCs), epithelial-mesenchymal transition (EMT), cancer heterogeneity, tumor microenvironment (TME), genetic mutations, and alterlations in gene expression. Additionally, we explore how tumors evade targeted therapies through pathway-specific mechanisms that restore disrupted signaling pathways. The review critically evaluates innovative strategies designed to sensitize resistant tumor cells, such as targeted protein dedgradation, antibody-drug conjugates, structure-based drug design, allosteric drugs, multitarget drugs, nanomedicine and others We also highlight the importance of understanding the pharmacological actions of these agents and their integration into treatment regimens. By synthesizing current knowledge and identifying gaps in our understanding, this review aims to guide future research and improve patient outcomes in cancer therapy.

A Review of FDA-Approved Multi-Target Angiogenesis Drugs for Brain Tumor Therapy

Neovascularization is an important process in brain tumor development, invasion and metastasis. Several research studies have indicated that the VEGF signaling target has potential for reducing angiogenesis in brain tumors. However, targeting VEGF signaling has not met the expected efficacy, despite initial enthusiasm. This is partly because tumors cleverly use alternative growth factor pathways, other than VEGF signaling, to restore angiogenesis. Multi-target inhibitors have been developed to inhibit several receptor kinases that play a role in the development of angiogenesis. By simultaneously affecting various receptor kinases, these treatments can potentially obstruct various angiogenic pathways that are involved in brain cancer advancement, often offering a more holistic strategy than treatments focusing on just one kinase. Since 2009, the FDA has approved a number of multi-kinase inhibitors that target angiogenic growth factor receptors (e.g., VEGFR, PDGFR, FGFR, RET, c-KIT, MET, AXL and others) for treatment of malignant diseases, including brain cancer. Here, we present some recent results from the literature regarding the preclinical and clinical effects of these inhibitors on brain tumors.

Glioblastoma multiforme: insights into pathogenesis, key signaling pathways, and therapeutic strategies

Glioblastoma multiforme (GBM) is the most prevalent and aggressive primary brain tumor in adults, characterized by a poor prognosis and significant resistance to existing treatments. Despite progress in therapeutic strategies, the median overall survival remains approximately 15 months. A hallmark of GBM is its intricate molecular profile, driven by disruptions in multiple signaling pathways, including PI3K/AKT/mTOR, Wnt, NF-κB, and TGF-β, critical to tumor growth, invasion, and treatment resistance. This review examines the epidemiology, molecular mechanisms, and therapeutic prospects of targeting these pathways in GBM, highlighting recent insights into pathway interactions and discovering new therapeutic targets to improve patient outcomes.

Low & Anaplastic Grade Glioma Umbrella Study of MOlecular Guided TherapieS (LUMOS-2): study protocol for a phase 2, prospective, multicentre, open-label, multiarm, biomarker-directed, signal-seeking, umbrella, clinical trial for recurrent IDH mutant, grade 2/3 glioma

INTRODUCTION

All grade 2/3 gliomas are incurable and at the time of inevitable relapse, patients have significant unmet needs with few effective treatments. This study aims to improve outcomes by molecular profiling of patients at relapse, then matching them with the best available drug based on their molecular profile, maximising the chances of patient benefit while simultaneously testing multiple novel drugs.

METHODS AND ANALYSIS

Low & Anaplastic Grade Glioma Umbrella Study of MOlecular Guided TherapieS (LUMOS-2) will be an international, phase 2, multicentre, open-label, biomarker-directed, umbrella clinical trial for recurrent isocitrate dehydrogenase mutant, histologically grade 2/3 gliomas. Investigational treatment will be assigned based on molecular profiling of contemporaneous tissue obtained at disease relapse using next-generation sequencing. LUMOS-2 will begin with three therapeutic treatment arms: paxalisib, cadonilimab and selinexor. Patient molecular profiles will be assessed by an expert, multidisciplinary Molecular Tumour Advisory Panel. Patients whose molecular profile is considered suitable for a targeted agent like paxalisib will be allocated to that arm, others will be randomised to the available arms of the trial. The primary endpoint is progression-free survival at 6 months. Secondary objectives include assessment of overall survival, response rate, safety and quality of life measures. Two additional therapeutic arms are currently in development.

ETHICS AND DISSEMINATION

Central ethics approval was obtained from the Sydney Local Health District Ethics Review Committee, Royal Prince Alfred Hospital Zone, Sydney, Australia (Approval: 2022/ETH02230). Other clinical sites will provide oversight through local governance processes, including obtaining informed consent from suitable participants. A report describing the results of the study will be submitted to international meetings and peer-reviewed journals.

TRIAL REGISTRATION NUMBER

ACTRN12623000096651.

Chimeric antigen receptor T-cell therapy in patients with malignant glioma-From neuroimmunology to clinical trial design considerations

Clinical trials evaluating chimeric antigen receptor (CAR) T-cell therapy in patients with malignant gliomas have shown some early promise in pediatric and adult patients. However, the long-term benefits and safety for patients remain to be established. The ultimate success of CAR T-cell therapy for malignant glioma will require the integration of an in-depth understanding of the immunology of the central nervous system (CNS) parenchyma with strategies to overcome the paucity and heterogeneous expression of glioma-specific antigens. We also need to address the cold (immunosuppressive) microenvironment, exhaustion of the CAR T-cells, as well as local and systemic immunosuppression. Here, we discuss the basics and scientific considerations for CAR T-cell therapies and highlight recent clinical trials. To help identify optimal CAR T-cell administration routes, we summarize our current understanding of CNS immunology and T-cell homing to the CNS. We also discuss challenges and opportunities related to clinical trial design and patient safety/monitoring. Finally, we provide our perspective on future prospects in CAR T-cell therapy for malignant gliomas by discussing combinations and novel engineering strategies to overcome immuno-regulatory mechanisms. We hope this review will serve as a basis for advancing the field in a multiple discipline-based and collaborative manner.

Protein kinase inhibitors as targeted therapy for glioblastoma: a meta-analysis of randomized controlled clinical trials

Glioblastoma (GBM) is the most common and lethal primary brain tumor. The standard treatment for newly diagnosed GBM includes surgical resection, when feasible, followed by radiotherapy and temozolomide-based chemotherapy. Upon disease progression, the anti-vascular endothelial growth factor-A (VEGF-A) monoclonal antibody bevacizumab, can be considered. Given the limited efficacy of pharmacological treatments, particularly for the recurrent disease, several molecularly targeted interventions have been explored, such as small-molecule protein kinase inhibitors (PKIs), inhibiting tyrosine kinase growth factor receptors and downstream signaling pathways involved in GBM angiogenesis and infiltrative behavior. This meta-analysis, based on searches in PubMed and Web Of Science, evaluated 12 randomized controlled trials (RCTs) examining PKIs in patients with newly diagnosed or recurrent GBM. Pooled analysis of shared clinical outcomes - progression-free survival (PFS) and overall survival (OS) - revealed a lack of significant improvements with the use of PKIs. In newly diagnosed GBM, no significant differences were observed in median [-1.02 months, 95 % confidence interval (CI), -2.37-0.32, p = 0.14] and pooled [hazard ratio (HR) = 1.13, 95 % CI, 0.95-1.35, p = 0.17) OS, or in median (0.34 months, 95 % CI, -0.9-1.58, p = 0.60) and pooled (HR = 0.98, 95 % CI, 0.76-1.27, p = 0.89) PFS, when comparing PKI addition to standard chemo-radiotherapy versus chemo-radiotherapy alone. In recurrent GBM, three different analyses were conducted: PKI versus other treatments, PKI combined with other treatments versus those treatments alone, PKI versus PKI combined with other treatments. Also, across these analyses, no significant clinical benefits were found. For instance, when comparing PKI treatment with other treatments, median OS and PFS showed no significant difference (-0.78 months, 95 % CI, -2.12-0.55, p = 0.25; -0.23 months, 95 % CI, -0.79-0.34, p = 0.43, respectively), and similar non-significant results were observed in the pooled analyses (OS: HR = 0.89, 95 % CI, 0.59-1.32, p = 0.55; PFS: HR = 0.83, 95 % CI, 0.63-1.11, p = 0.21). Despite these overall negative findings, some data indicate improved clinical outcomes in a subset of GBM patients treated with certain PKIs (i.e., regorafenib) and encourage further research to identify PKIs with better blood-brain barrier penetration and lower risk for resistance development.

Multikinase Treatment of Glioblastoma: Evaluating the Rationale for Regorafenib

We explored the rationale for treating glioblastoma (GBM) with regorafenib. In 103 newly diagnosed GBM patients, we assessed mutations, copy number variants (CNVs), fusions, and overexpression in 46 genes encoding protein kinases (PKs) potentially targeted by regorafenib or its metabolites and performed a functional enrichment analysis to assess their implications in angiogenesis. We analyzed regorafenib's binding inhibitory activity and target affinity for these 46 PKs and focused on a subset of 18 genes inhibited by regorafenib at clinically achievable concentrations and on 19 genes involved in angiogenesis. Putative oncogenic alterations were defined as oncogenic/likely oncogenic mutations, oncogenic fusions, CNVs > 5, and/or gene overexpression. Regorafenib did not target all 46 PKs. For the 46-gene set, 40 genes (86.9%) and 73 patients (70.8%) harbored at least one alteration in genes encoding targetable PKs, but putative oncogenic alterations were present in only 34 patients (33%). In the 18-gene set, 18 genes (100%) and 48 patients (46.6%) harbored alterations, but putative oncogenic alterations were detected in only 26 patients (25.2%). Thirty patients (29.1%) had oncogenic alterations in the 18-gene set and/or in angiogenesis-related genes. Around 33% of patients had oncogenic alterations in any of the 46 potential targets. Additionally, the suboptimal dosing of regorafenib, due to its poor penetration of the blood-brain barrier, may reduce the likelihood of effectively targeting certain PKs. Future use of multi-target drugs must be guided by a thorough understanding of target presence, effective inhibition, and the drug's ability to reach brain tumors at adequate concentrations.

Emerging Approaches in Glioblastoma Treatment: Modulating the Extracellular Matrix Through Nanotechnology

Glioblastoma's (GB) complex tumor microenvironment (TME) promotes its progression and resistance to therapy. A critical component of TME is the extracellular matrix (ECM), which plays a pivotal role in promoting the tumor's invasive behavior and aggressiveness. Nanotechnology holds significant promise for GB treatment, with the potential to address challenges posed by both the blood-brain barrier and the GB ECM. By enabling targeted delivery of therapeutic and diagnostic agents, nanotechnology offers the prospect of improving treatment efficacy and diagnostic accuracy at the tumor site. This review provides a comprehensive exploration of GB, including its epidemiology, classification, and current treatment strategies, alongside the intricacies of its TME. It highlights nanotechnology-based strategies, focusing on nanoparticle formulations such as liposomes, polymeric nanoparticles, and gold nanoparticles, which have shown promise in GB therapy. Furthermore, it explores how different emerging nanotechnology strategies modulate the ECM to overcome the challenges posed by its high density, which restricts drug distribution within GB tumors. By emphasizing the intersection of nanotechnology and GB ECM, this review underscores an innovative approach to advancing GB treatment. It addresses the limitations of current therapies, identifies new research avenues, and emphasizes the potential of nanotechnology to improve patient outcomes.

Emerging nanoplatforms towards microenvironment-responsive glioma therapy

Gliomas are aggressive intracranial tumors of the central nervous system with a poor prognosis, high risk of recurrence, and low survival rates. Radiation, surgery, and chemotherapy are traditional cancer therapies. It is very challenging to accurately image and differentiate the malignancy grade of gliomas due to their heterogeneous and infiltrating nature and the obstruction of the blood-brain barrier. Imaging plays a crucial role in gliomas which significantly plays an important role in the accuracy of the diagnosis followed by any subsequent surgery or therapy. Other diagnostic methods (such as biopsies or surgery) are often very invasive. Preoperative imaging and intraoperative image-guided surgery perform the most significant safe resection. In recent years, the rapid growth of nanotechnology has opened up new avenues for glioma diagnosis and treatment. For better therapeutic efficacy, developing microenvironment-responsive nanoplatforms, including novel nanotherapeutic platforms of sonodynamic therapy, photodynamic therapy, and photothermal treatments, are employed for improved patient survival and better clinical control outcome. In this review recent advancement of multifunctional nanoplatforms leading toward treatment of glioma is discussed.

A comprehensive review of targeting RAF kinase in cancer

RAF kinases, particularly the BRAF isoform, play a crucial role in the MAPK/ERK signaling pathway, regulating key cellular processes such as proliferation, differentiation, and survival. Dysregulation of this pathway often caused by mutations in the BRAF gene or alterations in upstream regulators like Ras and receptor tyrosine kinases contributes significantly to cancer development. Mutations, such as BRAF-V600E, are present in a variety of malignancies, with the highest prevalence in melanoma. Targeted therapies against RAF kinases have achieved substantial success, especially in BRAF-V600E-mutant melanomas, where inhibitors like vemurafenib and dabrafenib have demonstrated remarkable efficacy, leading to improved patient outcomes. These inhibitors have also shown clinical benefits in cancers such as thyroid and colorectal carcinoma, although to a lesser extent. Despite these successes, therapeutic resistance remains a major hurdle. Resistance mechanisms, including RAF dimerization, feedback reactivation of the MAPK pathway, and paradoxical activation of ERK signaling, often lead to diminished efficacy over time, resulting in disease progression or even secondary malignancies. In response, current research is focusing on novel therapeutic strategies, including combination therapies that target multiple components of the pathway simultaneously, such as MEK inhibitors used in tandem with RAF inhibitors. Additionally, next-generation RAF inhibitors are being developed to address resistance and enhance therapeutic specificity. This review discusses the clinical advancements in RAF-targeted therapies, with a focus on ongoing efforts to overcome therapeutic resistance and enhance outcomes for cancer patients. It also underscores the persistent challenges in effectively targeting RAF kinase in oncology.

Analysis of Clinical Success and Molecular Mechanisms of Action of Novel Anti-glioblastoma Drugs: A Review

BACKGROUND

Gliomas and glioblastomas (GBM) are common primary malignant brain tumors, which are highly malignant and have a poor prognosis. The presence of cancer stem cells with unrestricted proliferative capacity and ability to generate glial neoplastic cells, the diffuse nature of GBM, and other specific factors of GBM contribute to poor results of drug therapy in patients with GBM. Despite the worldwide efforts to improve the treatment, many novel anti-GBM drugs are active just in vitro, in silico, and in preclinical trials, and they sometimes demonstrate poor or no activity in clinical trials. In this paper, we have casually selected and analyzed the most promising evidence-based results related to glioblastoma treatment at FDA and Clinical Trials.gov databases. It was observed that the most prospective trend in the development of anti-GBM drugs is combination therapy vs. monotherapy. Our analysis of clinical trials has allowed us to predict that the most promising combination therapy that has shown the best results in patient's surveillance should include drugs that block different growth-promoting signals in glioblastoma cells and that are activated by the V600E BRAF mutation. One drug should inhibit signals from the BRAF protein, whereas the second drug in combination should inhibit signals from the MEK protein.

METHODS

The content of this review is based on information obtained from PubMed, ClinicalTrials.- gov, and the U.S. Food and Drug Administration (https://www.fda.gov/). In ClinicalTrials.gov, we retrieved studies published from January 1, 2015. In the data search, "Glioblastoma" was used as the keyword. A study was deleted if it studied remedies for concomitant tumor diseases, as well as if it did not include descriptions of treatment methods and/or if GBM was not mentioned. The analysis of the effectiveness of treatment was carried out according to the increasing overall survival in GBM patients, compared to the gold standard for this cancer.

RESULTS

GBM patients treated with novel immunotherapy agents and drugs acting on epigenetic factors and receptor tyrosine kinase inhibitors have shown encouraging potential for future development in clinic. However, combinations of drugs have led to more significant improvements in the results and an increase in life expectancy of patients. For example, the combination of nivolumab and ipilimumab showed a 72% increase in life expectancy compared to using nivolumab alone (9.8 vs. 16.85).

CONCLUSION

Combining anti-GBM drugs appears to be a key direction for increasing treatment effectiveness and overall survival. Radiotherapy of GBM can increase the effect of combination drug therapy.

Ultrasmall solid lipid nanoparticles as a potential innovative delivery system for a drug combination against glioma

INTRODUCTION

High grade gliomas are characterized by a very poor prognosis due to fatal relapses after surgery. Current chemotherapy is only a palliative care, while potential drug candidates are limited by poor overcoming of the blood-brain barrier.

AIMS

A suitable chemotherapeutic approach should be engineered to overcome both the altered blood-brain barrier in the glioma site, as well as the intact one in the brain adjacent to tumor zone, and to target the multiple factors influencing glioma proliferation, differentiation, migration, and angiogenesis.

MATERIALS & METHODS

In this experimental research, ultrasmall solid lipid nanoparticles were prepared owing to the temperature phase inversion technology and loaded with a specific drug combination made of paclitaxel, regorafenib, and nanoceria.

RESULTS

Such solid lipid nanoparticles demonstrated capability to inhibit glioma cell proliferation and migration, as well as angiogenesis in vitro. Moreover, relevant in vivo evidence assessed the accumulation of solid lipid nanoparticles in the glioma site of the F98/Fischer rat model, without causing any off-target toxicity.

CONCLUSIONS

Thus, promising results for glioma treatment were obtained with a technology characterized by safety and economy, allowing the perspective of successful scalability.

Regorafenib Treatment for Recurrent Glioblastoma Beyond Bevacizumab-Based Therapy: A Large, Multicenter, Real-Life Study

BACKGROUND/OBJECTIVES

In the REGOMA trial, regorafenib demonstrated an overall survival advantage over lomustine, and it has become a recommended treatment for recurrent glioblastoma in guidelines. This study aimed to evaluate the effectiveness and safety of regorafenib as a third-line treatment for patients with recurrent glioblastoma who progressed while taking bevacizumab-based therapy.

METHODS

This retrospective, multicenter study in Turkey included 65 patients treated between 2021 and 2023 across 19 oncology centers. The main inclusion criteria were histologically confirmed isocitrate dehydrogenase (IDH)-wildtype glioblastoma, progression after second-line bevacizumab-based treatment, and an Eastern Cooperative Oncology Group (ECOG) performance status score of ≤2. Patients received regorafenib 160 mg once daily for the first 3 weeks of each 4-week cycle.

RESULTS

The median age of the patients was 53 years (18-67 years), with a median progression-free survival of 2.5 months (95% Confidence Interval: 2.23-2.75) and a median overall survival of 4.1 months (95% CI: 3.52-4.68). The median overall survival was improved in patients who received subsequent therapy after regorafenib treatment compared with those who did not (p = 0.022). Progression-free survival was longer in patients with ECOG 0-1 than in those with ECOG 2 (p = 0.042). The safety profile was consistent with that of the REGOMA trial, with no drug-related deaths observed.

CONCLUSIONS

Regorafenib shows good efficacy and safety as a third-line treatment for recurrent glioblastoma after bevacizumab-based therapy. This study supports the use of regorafenib and emphasizes the need for further randomized studies to validate its role and optimize treatment strategies.

Identifying the best treatment choice for relapsing/refractory glioblastoma: a systematic review with multiple Bayesian network meta-analyses

BACKGROUND

Glioblastoma is a highly aggressive primary central nervous system tumor characterized by poor outcomes. In case of relapse or progression to adjuvant chemotherapy, there is no univocal preferred regimen for relapsing glioblastoma.

METHODS

We conducted a systematic review and Bayesian trial-level network meta-analyses (NMA) to identify the regimens associated with the best outcomes. The primary endpoint was overall survival (OS). Secondary endpoints were progression-free survival (PFS) and overall response rates (ORR). We estimated separate treatment rankings based on the surface under the cumulative ranking curve values. Only phase II/III prospective comparative trials were included.

RESULTS

Twenty-four studies (3733 patients and 27 different therapies) were ultimately included. Twenty-three different regimens were compared for OS, 21 for PFS, and 26 for ORR. When taking lomustine as a common comparator, only regorafenib was likely to be significantly superior in terms of OS (hazard ratio: 0.50, 95% credible interval: 0.33-0.75). Regorafenib was significantly superior to other 16 (69.6%) regimens, including NovoTTF-100A, bevacizumab monotherapy, and several bevacizumab-based combinations. Regarding PFS and ORR, no treatment was clearly superior to the others.

CONCLUSIONS

This NMA supports regorafenib as one of the best available options for relapsing/refractory glioblastoma. Lomustine, NovoTTF-100A, and bevacizumab emerge as other viable alternative regimens. However, evidence on regorafenib is controversial at best. Moreover, most studies were underpowered, with varying inclusion criteria and primary endpoints, and no longer adapted to the most recent glioblastoma classification. A paradigmatic change in clinical trials' design for relapsing/refractory glioblastoma and more effective treatments are urgently required.

Current status of precision oncology in adult glioblastoma

The concept of precision oncology, the application of targeted drugs based on comprehensive molecular profiling, has revolutionized treatment strategies in oncology. This review summarizes the current status of precision oncology in glioblastoma (GBM), the most common and aggressive primary brain tumor in adults with a median survival below 2 years. Targeted treatments without prior target verification have consistently failed. Patients with BRAF V600E-mutated GBM benefit from BRAF/MEK-inhibition, whereas targeting EGFR alterations was unsuccessful due to poor tumor penetration, tumor cell heterogeneity, and pathway redundancies. Systematic screening for actionable molecular alterations resulted in low rates (< 10%) of targeted treatments. Efficacy was observed in one-third and currently appears to be limited to BRAF-, VEGFR-, and mTOR-directed treatments. Advancing precision oncology for GBM requires consideration of pathways instead of single alterations, new trial concepts enabling rapid and adaptive drug evaluation, a focus on drugs with sufficient bioavailability in the CNS, and the extension of target discovery and validation to the tumor microenvironment, tumor cell networks, and their interaction with immune cells and neurons.

Novel strategies to overcome chemoresistance in human glioblastoma

Temozolomide (TMZ) is currently the first-line chemotherapeutic agent for the treatment of glioblastoma multiforme (GBM). However, the inherent heterogeneity of GBM often results in suboptimal outcomes, particularly due to varying degrees of resistance to TMZ. Over the past several decades, O6-methylguanine-DNA methyltransferase (MGMT)-mediated DNA repair pathway has been extensively investigated as a target to overcome TMZ resistance. Nonetheless, the combination of small molecule covalent MGMT inhibitors with TMZ and other chemotherapeutic agents has frequently led to adverse clinical effects. Recently, additional mechanisms contributing to TMZ resistance have been identified, including epidermal growth factor receptor (EGFR) mutations, overactivation of intracellular signalling pathways, energy metabolism reprogramming or survival autophagy, and changes in tumor microenvironment (TME). These findings suggest that novel therapeutic strategies targeting these mechanisms hold promise for overcoming TMZ resistance in GBM patients. In this review, we summarize the latest advancements in understanding the mechanisms underlying intrinsic and acquired TMZ resistance. Additionally, we compile various small-molecule compounds with potential to mitigate chemoresistance in GBM. These mechanism-based compounds may enhance the sensitivity of GBM to TMZ and related chemotherapeutic agents, thereby improving overall survival rates in clinical practice.

PARP inhibitors in gliomas: Mechanisms of action, current trends and future perspectives

Gliomas are the most common primary malignant brain tumours in adults. Despite decades of research into novel therapeutic approaches, the prognosis remains poor. PARP1-2 are critical for DNA repair, cell survival and genomic stability and PARP inhibition (PARPi) may be a promising therapeutic approach for gliomas. Inhibition of PARP activity leads to homologous recombination deficiency (HRD), which, in combination with DNA damage, results in cell death. This review summarises the current knowledge and future perspectives of PARPi in glioma. The available literature was reviewed using PubMed, recent major international oncology congresses were consulted, and ongoing clinical trials were searched using ClinicalTrials.gov. In translational research, PARPi have demonstrated a strong scientific rationale for their use in the treatment of glioma. They have been evaluated both alone and in combination with radiotherapy, temozolomide, anti-angiogenic agents, immunotherapy and other new drugs in newly diagnosed or recurrent glioma. Most studies were open-label, non-randomised, dose-escalation phase I-II trials. Early results show promising anti-tumour activity, and key challenges include identifying predictive biomarkers, elucidating synergistic effects in combination therapies, addressing the development of resistance, and managing hematological toxicity. In conclusion, early phase studies have shown promising anti-tumour activity of PARPi that should be confirmed in larger prospective and randomised trials. In addition, the development of novel PARPi with improved blood brain barrier (BBB) penetration and PARP inhibitor activity with new synergistic treatment combinations seems promising and needs to be further explored.

Schisandrin C prevents regorafenib-induced cardiotoxicity by recovering EPHA2 expression in cardiomyocytes

Regorafenib, an oral multikinase inhibitor of angiogenic, stromal, and oncogenic receptor tyrosine kinases, has been approved for the treatment of metastatic colorectal cancer, gastrointestinal stromal tumors, and hepatocellular carcinoma by the US Food and Drug Administration and European Medicines Agency. However, regorafenib-induced cardiotoxicity increases the risk of mortality. Despite reports that regorafenib can cause mitochondrial dysfunction in cardiomyocytes, the molecular mechanism of regorafenib-induced cardiotoxicity is much less known and there is an urgent need for intervention strategies. Here, we treated mice with vehicle or 200 mg/kg regorafenib daily for 42 d by gavage or treated cardiomyocyte lines with 8, 16, or 32 μM regorafenib, and we found that regorafenib could cause apoptosis, mitochondrial injury, and DNA damage in cardiomyocytes. Mechanistically, regorafenib can reduce the expression of EPHA2, which inhibits AKT signaling, leading to cardiomyocyte apoptosis and cardiotoxicity. In addition, we showed that recovering EPHA2 expression via plasmid-induced overexpression of EPHA2 or schisandrin C, a natural product, could prevent regorafenib-induced cardiotoxicity. These findings demonstrated that regorafenib causes cardiomyocyte apoptosis and cardiac injury by reducing the expression of EPHA2 and schisandrin C could prevent regorafenib-induced cardiotoxicity by recovering EPHA2 expression, which provides a potential management strategy for regorafenib-induced cardiotoxicity and will benefit the safe application of regorafenib in clinic.

Novel Fibroblast Growth Factor Receptor 3-Fatty Acid Synthase Gene Fusion in Recurrent Epithelioid Glioblastoma Linked to Aggressive Clinical Progression

Glioblastoma (GBM) is the most common primary malignant brain tumor in adults, with a median overall survival (OS) of 15-18 months despite standard treatments. Approximately 8% of GBM cases exhibit genomic alterations in fibroblast growth factor receptors (FGFRs), particularly FGFR1 and FGFR3. Next-generation sequencing techniques have identified various FGFR3 fusions in GBM. This report presents a novel FGFR3 fusion with fatty acid synthase (FASN) in a 41-year-old male diagnosed with GBM. The patient presented with a persistent headache, and imaging revealed a right frontal lobe lesion. Surgical resection and subsequent histopathology confirmed GBM. Initial NGS analysis showed no mutations in the IDH1, IDH2 or H3F3 genes, but revealed a TERT promoter mutation and CDKN2A/2B and PTEN deletions. Postoperative treatment included radiotherapy and temozolomide. Despite initial management, recurrence occurred four months post-diagnosis, confirmed by MRI and histology. A second surgery identified a novel FGFR3-FASN fusion, alongside increased Ki67 expression. The recurrence was managed with regorafenib and bevacizumab, though complications like hand-foot syndrome and radiation necrosis arose. Despite initial improvement, the patient died 15 months after diagnosis. This case underscores the importance of understanding GBM's molecular landscape for effective treatment strategies. The novel FGFR3-FASN fusion suggests potential implications for GBM recurrence and lipid metabolism. Further studies are warranted to explore FGFR3-FASN's role in GBM and its therapeutic targeting.

Efficacy and Low Toxicity of Normo-Fractionated Re-Irradiation with Combined Chemotherapy for Recurrent Glioblastoma-An Analysis of Treatment Response and Failure

BACKGROUND

Glioblastoma is the most common malignant brain tumor in adults. Even after maximal safe resection and adjuvant chemoradiotherapy, patients normally relapse after a few years or even months. Standard treatment for recurrent glioblastoma is not yet defined, with re-resection, re-irradiation, and systemic therapy playing key roles. Usually, re-irradiation is combined with concurrent chemotherapy, harnessing the radiosensitizing effects of alkylating agents.

METHODS

A retrospective analysis of 101 patients with recurrent glioblastoma treated with re-irradiation was conducted, evaluating the survival impact of concurrent chemotherapy regimens, as well as prior resection. Patients were subcategorized according to concurrent chemotherapy (temozolomide vs. CCNU vs. combination of both vs. none) and details are given regarding treatment toxicity and patterns of relapse after first- and second-line treatment.

RESULTS

Patients were treated with normo-fractionated re-irradiation (with prescription dose of ~40 Gy to the PTV), resulting in a moderate cumulative EQD2 (~100 Gy). The mean overall survival was 11.3 months (33.5 months from initial diagnosis) and mean progression free survival was 9.5 months. Prior resection resulted in increased survival (p < 0.001), especially when gross total resection was achieved. Patients who received concurrent chemotherapy had significantly longer survival vs. no chemotherapy (p < 0.01), with the combination of CCNU and TMZ achieving the best results. Overall survival was significantly better in patients who received the CCNU + TMZ combination at any time during treatment (first or second line) vs. monotherapy only. The treatment of larger volumes (mean PTV size = 112.7 cm3) was safe and did not result in worse prognosis or increased demand for corticosteroids. Overall, the incidence of high-grade toxicity or sequential radionecrosis (5%) was reasonably low and treatment was tolerated well. While second-line chemotherapy did not seem to influence patterns of relapse, patients who received TMZ + CCNU as first-line treatment had a tendency towards better local control with more out-field recurrence.

CONCLUSIONS

Normo-fractionated re-irradiation appears to be safe and is accompanied by good survival outcomes, even when applied to larger treatment volumes. Patients amenable to undergo re-resection and achieving concurrent systemic therapy with alkylating agents had better OS, especially when gross total resection was possible. Based on existing data and experiences reflected in this analysis, we advocate for a multimodal approach to recurrent glioblastoma with maximal safe re-resection and adjuvant second chemoradiation. The combination of TMZ and CCNU for patients with methylated MGMT promoter yielded the best results in the primary and recurrent situation (together with re-RT). Normo-fractionated RT enables the use of more generous margins and is tolerated well.

Tumor treating induced fields: a new treatment option for patients with glioblastoma

Purpose

Currently, a range of electromagnetic therapies, including magnetic field therapy, micro-currents therapy, and tumor treating fields, are under investigation for their potential in central nervous system tumor research. Each of these electromagnetic therapies possesses distinct effects and limitations. Our focus is on overcoming these limitations by developing a novel electric field generator. This generator operates by producing alternating induced currents within the tumor area through electromagnetic induction.

Methods

Finite element analysis was employed to calculate the distribution of electric fields. Cell viability was assessed using the CCK-8 assay. Tumor volumes and weights served as indicators to evaluate the effectiveness of TTIF. The in-vivo imaging system was utilized to confirm tumor growth in the brains of mice.

Results

TTIF significantly inhibited the proliferation of U87 cells both in vitro and in vivo.

Conclusion

TTIF significantly inhibited the proliferation of U87 cells both in vitro and in vivo. Consequently, TTIF emerges as a potential treatment option for patients with progressive or metastatic GBM.

Challenges and advances in glioblastoma targeted therapy: the promise of drug repurposing and biomarker exploration

Glioblastoma remains the most prevalent and aggressive primary malignant brain tumor in adults, characterized by limited treatment options and a poor prognosis. Previous drug repurposing efforts have yielded only marginal survival benefits, particularly those involving inhibitors targeting receptor tyrosine kinase and cyclin-dependent kinase-retinoblastoma pathways. This limited efficacy is likely due to several critical challenges, including the tumor's molecular heterogeneity, the dynamic evolution of its genetic profile, and the restrictive nature of the blood-brain barrier that impedes effective drug delivery. Emerging diagnostic tools, such as circulating tumor DNA and extracellular vesicles, offer promising non-invasive methods for real-time tumor monitoring, potentially enabling the application of targeted therapies to more selected patient populations. Moreover, innovative drug delivery strategies, including focused ultrasound, implantable drug-delivery systems, and engineered nanoparticles, hold potential for enhancing the bioavailability and therapeutic efficacy of treatments.

Review of Novel Surgical, Radiation, and Systemic Therapies and Clinical Trials in Glioblastoma

Glioblastoma (GBM) is the most common malignant primary brain tumor in adults. Despite an established standard of care including surgical resection, radiation therapy, and chemotherapy, GBM unfortunately is associated with a dismal prognosis. Therefore, researchers are extensively evaluating avenues to expand GBM therapy and improve outcomes in patients with GBM. In this review, we provide a broad overview of novel GBM therapies that have recently completed or are actively undergoing study in clinical trials. These therapies expand across medical, surgical, and radiation clinical trials. We additionally review methods for improving clinical trial design in GBM.

Reirradiation with radiosurgery or stereotactic fractionated radiotherapy in association with regorafenib in recurrent glioblastoma

PURPOSE

No standard treatment has yet been established for recurrent glioblastoma (GBM). In this context, the aim of the current study was to evaluate safety and efficacy of reirradiation (re-RT) by radiosurgery or fractionated stereotactic radiotherapy (SRS/FSRT) in association with regorafenib.

METHODS

Patients with a histological or radiological diagnosis of recurrent GBM who received re-RT by SRS/FSRT and regorafenib as second-line systemic therapy were included in the analysis.

RESULTS

From January 2020 to December 2022, 21 patients were evaluated. The median time between primary/adjuvant RT and disease recurrence was 8 months (range 5-20). Median re-RT dose was 24 Gy (range 18-36 Gy) for a median number of 5 fractions (range 1-6). Median regorafenib treatment duration was 12 weeks (range 3-26). Re-RT was administered before starting regorafenib or in the week off regorafenib during the course of chemotherapy. The median and the 6‑month overall survival (OS) from recurrence were 8.4 months (95% confidence interval [CI] 6.9-12.7 months) and 75% (95% CI 50.9-89.1%), respectively. The median progression-free survival (PFS) from recurrence was 6 months (95% CI 3.7-8.5 months). The most frequent side effects were asthenia that occurred in 10 patients (8 cases of grade 2 and 2 cases of grade 3), and hand-foot skin reaction (2 patients grade 3, 3 patients grade 2). Adverse events led to permanent regorafenib discontinuation in 2 cases, while in 5/21 cases (23.8%), a dose reduction was administered. One patient experienced dehiscence of the surgical wound after reintervention and during regorafenib treatment, while another patient reported intestinal perforation that required hospitalization.

CONCLUSION

For recurrent GBM, re-RT with SRT/FSRT plus regorafenib is a safe treatment. Prospective trials are necessary.

Opportunities and Challenges of Small Molecule Inhibitors in Glioblastoma Treatment: Lessons Learned from Clinical Trials

Glioblastoma (GBM) is the most prevalent central nervous system tumour (CNS). Patients with GBM have a dismal prognosis of 15 months, despite an intensive treatment schedule consisting of surgery, chemoradiation and concurrent chemotherapy. In the last decades, many trials have been performed investigating small molecule inhibitors, which target specific genes involved in tumorigenesis. So far, these trials have been unsuccessful, and standard of care for GBM patients has remained the same since 2005. This review gives an overview of trials investigating small molecule inhibitors on their own, combined with chemotherapy or other small molecule inhibitors. We discuss possible resistance mechanisms in GBM, focussing on intra- and intertumoral heterogeneity, bypass mechanisms and the influence of the tumour microenvironment. Moreover, we emphasise how combining inhibitors can help overcome these resistance mechanisms. We also address strategies for improving trial outcomes through modifications to their design. In summary, this review aims to elucidate different resistance mechanisms against small molecule inhibitors, highlighting their significance in the search for novel therapeutic combinations to improve the overall survival of GBM patients.

Sequential Inhibition of PARP and BET as a Rational Therapeutic Strategy for Glioblastoma

PARP inhibitors (PARPi) hold substantial promise in treating glioblastoma (GBM). However, the adverse effects have restricted their broad application. Through unbiased transcriptomic and proteomic sequencing, it is discovered that the BET inhibitor (BETi) Birabresib profoundly alters the processes of DNA replication and cell cycle progression in GBM cells, beyond the previously reported impact of BET inhibition on homologous recombination repair. Through in vitro experiments using established GBM cell lines and patient-derived primary GBM cells, as well as in vivo orthotopic transplantation tumor experiments in zebrafish and nude mice, it is demonstrated that the concurrent administration of PARPi and BETi can synergistically inhibit GBM. Intriguingly, it is observed that DNA damage lingers after discontinuation of PARPi monotherapy, implying that sequential administration of PARPi followed by BETi can maintain antitumor efficacy while reducing toxicity. In GBM cells with elevated baseline replication stress, the sequential regimen exhibits comparable efficacy to concurrent treatment, protecting normal glial cells with lower baseline replication stress from DNA toxicity and subsequent death. This study provides compelling preclinical evidence supporting the development of innovative drug administration strategies focusing on PARPi for GBM therapy.

The STELLAR trial: a phase II/III randomized trial of high-dose, intermittent sunitinib in patients with recurrent glioblastoma

Previously, the tyrosine kinase inhibitor sunitinib failed to show clinical benefit in patients with recurrent glioblastoma. Low intratumoural sunitinib accumulation in glioblastoma patients was reported as a possible explanation for the lack of therapeutic benefit. We designed a randomized phase II/III trial to evaluate whether a high-dose intermittent sunitinib schedule, aimed to increase intratumoural drug concentrations, would result in improved clinical benefit compared to standard treatment with lomustine. Patients with recurrent glioblastoma were randomized 1:1 to high-dose intermittent sunitinib 300 mg once weekly (Q1W, part 1) or 700 mg once every two weeks (Q2W, part 2) or lomustine. The primary end-point was progression-free survival. Based on the pre-planned interim analysis, the trial was terminated for futility after including 26 and 29 patients in parts 1 and 2. Median progression-free survival of sunitinib 300 mg Q1W was 1.5 months (95% CI 1.4-1.7) compared to 1.5 months (95% CI 1.4-1.6) in the lomustine arm (P = 0.59). Median progression-free survival of sunitinib 700 mg Q2W was 1.4 months (95% CI 1.2-1.6) versus 1.6 months (95% CI 1.3-1.8) for lomustine (P = 0.70). Adverse events (≥grade 3) were observed in 25%, 21% and 31% of patients treated with sunitinib 300 mg Q1W, sunitinib 700 mg Q2W and lomustine, respectively (P = 0.92). To conclude, high-dose intermittent sunitinib treatment failed to improve the outcome of patients with recurrent glioblastoma when compared to standard lomustine therapy. Since lomustine remains a poor standard treatment strategy for glioblastoma, innovative treatment strategies are urgently needed.

Evaluation of ex vivo drug combination optimization platform in recurrent high grade astrocytic glioma: An interventional, non-randomized, open-label trial protocol

INTRODUCTION

High grade astrocytic glioma (HGG) is a lethal solid malignancy with high recurrence rates and limited survival. While several cytotoxic agents have demonstrated efficacy against HGG, drug sensitivity testing platforms to aid in therapy selection are lacking. Patient-derived organoids (PDOs) have been shown to faithfully preserve the biological characteristics of several cancer types including HGG, and coupled with the experimental-analytical hybrid platform Quadratic Phenotypic Optimization Platform (QPOP) which evaluates therapeutic sensitivity at a patient-specific level, may aid as a tool for personalized medical decisions to improve treatment outcomes for HGG patients.

METHODS

This is an interventional, non-randomized, open-label study, which aims to enroll 10 patients who will receive QPOP-guided chemotherapy at the time of first HGG recurrence following progression on standard first-line therapy. At the initial presentation of HGG, tumor will be harvested for primary PDO generation during the first biopsy/surgery. At the point of tumor recurrence, patients will be enrolled onto the main study to receive systemic therapy as second-line treatment. Subjects who undergo surgery at the time of recurrence will have a second harvest of tissue for PDO generation. Established PDOs will be subject to QPOP analyses to determine their therapeutic sensitivities to specific panels of drugs. A QPOP-guided treatment selection algorithm will then be used to select the most appropriate drug combination. The primary endpoint of the study is six-month progression-free survival. The secondary endpoints include twelve-month overall survival, RANO criteria and toxicities. In our radiological biomarker sub-study, we plan to evaluate novel radiopharmaceutical-based neuroimaging in determining blood-brain barrier permeability and to assess in vivo drug effects on tumor vasculature over time.

TRIAL REGISTRATION

This trial was registered on 8th September 2022 with ClinicalTrials.gov Identifier: NCT05532397.

Neuroinflammation in Glioblastoma: Progress and Perspectives

Glioblastoma is the most common and malignant primary brain tumor, with high morbidity and mortality. Despite an aggressive, multimodal treatment regimen, including surgical resection followed by chemotherapy and radiotherapy, the prognosis of glioblastoma patients remains poor. One formidable challenge to advancing glioblastoma therapy is the complexity of the tumor microenvironment. The tumor microenvironment of glioblastoma is a highly dynamic and heterogeneous system that consists of not only cancerous cells but also various resident or infiltrating inflammatory cells. These inflammatory cells not only provide a unique tumor environment for glioblastoma cells to develop and grow but also play important roles in regulating tumor aggressiveness and treatment resistance. Targeting the tumor microenvironment, especially neuroinflammation, has increasingly been recognized as a novel therapeutic approach in glioblastoma. In this review, we discuss the components of the tumor microenvironment in glioblastoma, focusing on neuroinflammation. We discuss the interactions between different tumor microenvironment components as well as their functions in regulating glioblastoma pathogenesis and progression. We will also discuss the anti-tumor microenvironment interventions that can be employed as potential therapeutic targets.

Revolutionizing Brain Tumor Care: Emerging Technologies and Strategies

Glioblastoma multiforme (GBM) is one of the most aggressive forms of brain tumor, characterized by a daunting prognosis with a life expectancy hovering around 12-16 months. Despite a century of relentless research, only a select few drugs have received approval for brain tumor treatment, largely due to the formidable barrier posed by the blood-brain barrier. The current standard of care involves a multifaceted approach combining surgery, irradiation, and chemotherapy. However, recurrence often occurs within months despite these interventions. The formidable challenges of drug delivery to the brain and overcoming therapeutic resistance have become focal points in the treatment of brain tumors and are deemed essential to overcoming tumor recurrence. In recent years, a promising wave of advanced treatments has emerged, offering a glimpse of hope to overcome the limitations of existing therapies. This review aims to highlight cutting-edge technologies in the current and ongoing stages of development, providing patients with valuable insights to guide their choices in brain tumor treatment.

Unlocking Hope: Anti-VEGFR inhibitors and their potential in glioblastoma treatment

PURPOSE

This systematic review summarizes evidence of VEGFR gene mutations and VEGF/VEGFR protein expression in glioblastoma multiforme (GBM) patients, alongside the efficacy and safety of anti-VEGFR tyrosine kinase inhibitors (TKIs) for GBM treatment.

METHODS

A comprehensive literature review was conducted using PubMed up to August 2023. Boolean operators and MeSH term "glioma," along with specific VEGFR-related keywords, were utilized following thorough examination of existing literature.

RESULTS

VEGFR correlates with glioma grade and GBM progression, presenting a viable therapeutic target. Regorafenib and axitinib show promise among studied TKIs. Other multi-targeted TKIs (MTKI) and combination therapies exhibit potential, albeit limited by blood-brain barrier penetration and toxicity. Combining treatments like radiotherapy and enhancing BBB penetration may benefit patients. Further research is warranted in patient quality of life and biomarker-guided selection.

CONCLUSION

While certain therapies hold promise for GBM, future research should prioritize personalized medicine and innovative strategies for improved treatment outcomes.

Targeted agents in patients with progressive glioblastoma-A systematic meta-analysis of randomized clinical trials

BACKGROUND

Glioblastoma (GB) is the most common malignant primary brain tumor in adults and is associated with a poor prognosis. Current treatment guidelines outline the standard of care for patients with newly diagnosed GB; however, there is currently no well-established consensus for the treatment of progressive GB. With this systematic meta-analysis of recently published randomized controlled trials (RCTs), we aim to establish evidence on targeted agents in the treatment of patients with progressive GB.

MATERIAL AND METHODS

We conducted searches across the Cochrane Library, Pubmed, MEDLINE (Ovid), ClinicalTrials.gov, WHO's International Clinical Trials Registry Platform and Google Scholar, encompassing the time span from 1954 to 2022, aiming to identify RCTs evaluating targeted therapies in patients with progressive GB. In order to perform a random-effects meta-analysis, we extracted hazard ratios (HRs) of overall survival (OS) and progression-free survival (PFS).

RESULTS

We included 16 RCTs (n = 3025 patients) in the systematic meta-analysis. Formally, regorafenib (RR 0.50; 95% CI 0.33-0.75), Depatux-M + TMZ (RR 0.66; 95% CI 0.47-0.93) and rindopepimut + bevacizumab (RR 0.53; 95% CI 0.32-0.88) were associated with an improved OS compared to the control arm. The combination of bevacizumab + CCNU (RR = 0.49; 95% CI 0.35-0.69) and regorafenib (RR 0.65; 95% CI 0.44-0.95) were formally associated with improved PFS.

CONCLUSIONS

The aim of this systematic meta-analysis was to establish evidence for the use of targeted therapies in progressive GB. While some studies demonstrated benefits for OS and/or PFS, those results have to be interpreted with caution as most studies had major methodological weaknesses, including potential differences in sample size, trial design, or the initial distribution of prognostic factors.

L-RNA aptamer-based CXCL12 inhibition combined with radiotherapy in newly-diagnosed glioblastoma: dose escalation of the phase I/II GLORIA trial

The chemokine CXCL12 promotes glioblastoma (GBM) recurrence after radiotherapy (RT) by facilitating vasculogenesis. Here we report outcomes of the dose-escalation part of GLORIA (NCT04121455), a phase I/II trial combining RT and the CXCL12-neutralizing aptamer olaptesed pegol (NOX-A12; 200/400/600 mg per week) in patients with incompletely resected, newly-diagnosed GBM lacking MGMT methylation. The primary endpoint was safety, secondary endpoints included maximum tolerable dose (MTD), recommended phase II dose (RP2D), NOX-A12 plasma levels, topography of recurrence, tumor vascularization, neurologic assessment in neuro-oncology (NANO), quality of life (QOL), median progression-free survival (PFS), 6-months PFS and overall survival (OS). Treatment was safe with no dose-limiting toxicities or treatment-related deaths. The MTD has not been reached and, thus, 600 mg per week of NOX-A12 was established as RP2D for the ongoing expansion part of the trial. With increasing NOX-A12 dose levels, a corresponding increase of NOX-A12 plasma levels was observed. Of ten patients enrolled, nine showed radiographic responses, four reached partial remission. All but one patient (90%) showed at best response reduced perfusion values in terms of relative cerebral blood volume (rCBV). The median PFS was 174 (range 58-260) days, 6-month PFS was 40.0% and the median OS 389 (144-562) days. In a post-hoc exploratory analysis of tumor tissue, higher frequency of CXCL12+ endothelial and glioma cells was significantly associated with longer PFS under NOX-A12. Our data imply safety of NOX-A12 and its efficacy signal warrants further investigation.

Overcoming Resistance to Temozolomide in Glioblastoma: A Scoping Review of Preclinical and Clinical Data

Glioblastoma (GB) is the most common and most aggressive primary brain tumor in adults, with an overall survival almost 14.6 months. Optimal resection followed by combined temozolomide chemotherapy and radiotherapy, also known as Stupp protocol, remains the standard of treatment; nevertheless, resistance to temozolomide, which can be obtained throughout many molecular pathways, is still an unsurpassed obstacle. Several factors influence the efficacy of temozolomide, including the involvement of other DNA repair systems, aberrant signaling pathways, autophagy, epigenetic modifications, microRNAs, and extracellular vesicle production. The blood-brain barrier, which serves as both a physical and biochemical obstacle, the tumor microenvironment's pro-cancerogenic and immunosuppressive nature, and tumor-specific characteristics such as volume and antigen expression, are the subject of ongoing investigation. In this review, preclinical and clinical data about temozolomide resistance acquisition and possible ways to overcome chemoresistance, or to treat gliomas without restoration of chemosensitinity, are evaluated and presented. The objective is to offer a thorough examination of the clinically significant molecular mechanisms and their intricate interrelationships, with the aim of enhancing understanding to combat resistance to TMZ more effectively.

Preferred Imaging for Target Volume Delineation for Radiotherapy of Recurrent Glioblastoma: A Literature Review of the Available Evidence

BACKGROUND

Recurrence in glioblastoma lacks a standardized treatment, prompting an exploration of re-irradiation's efficacy.

METHODS

A comprehensive systematic review from January 2005 to May 2023 assessed the role of MRI sequences in recurrent glioblastoma re-irradiation. The search criteria, employing MeSH terms, targeted English-language, peer-reviewed articles. The inclusion criteria comprised both retrospective and prospective studies, excluding certain types and populations for specificity. The PICO methodology guided data extraction, and the statistical analysis employed Chi-squared tests via MedCalc v22.009.

RESULTS

Out of the 355 identified studies, 81 met the criteria, involving 3280 patients across 65 retrospective and 16 prospective studies. The key findings indicate diverse treatment modalities, with linac-based photons predominating. The median age at re-irradiation was 54 years, and the median time interval between radiation courses was 15.5 months. Contrast-enhanced T1-weighted sequences were favored for target delineation, with PET-imaging used in fewer studies. Re-irradiation was generally well tolerated (median G3 adverse events: 3.5%). The clinical outcomes varied, with a median 1-year local control rate of 61% and a median overall survival of 11 months. No significant differences were noted in the G3 toxicity and clinical outcomes based on the MRI sequence preference or PET-based delineation.

CONCLUSIONS

In the setting of recurrent glioblastoma, contrast-enhanced T1-weighted sequences were preferred for target delineation, allowing clinicians to deliver a safe and effective therapeutic option; amino acid PET imaging may represent a useful device to discriminate radionecrosis from recurrent disease. Future investigations, including the ongoing GLIAA, NOA-10, ARO 2013/1 trial, will aim to refine approaches and standardize methodologies for improved outcomes in recurrent glioblastoma re-irradiation.

Glioblastoma: a comprehensive approach combining bibliometric analysis, Latent Dirichlet Allocation, and HJ-Biplot : Glioblastoma insights and trends: a 49-year bibliometric analysis

Glioblastoma is a common and aggressive malignant central nervous system tumor in adults. This study aims to evaluate and analyze the scientific results, collaboration countries, main research topics, and topics over time reported about glioblastoma. A bibliometric analysis of glioblastoma publications was performed mainly using R and Multbiplot software for author, journal, and resume. Associated statistic methods Latent Dirichlet Allocation (LDA) and HJ-Biplot. Inclusion criteria were research articles from the PubMed database published in English between 1973 and December 2022. A total of 64,823 documents with an annual growth rate of 8.27% indicates a consistent increase in research output over time. The results for the number of citations and significant publications showed Cancer Res, J Neuro-Oncol, and Neuro-Oncology are the most influential journals in the field of glioblastoma. The countries that concentrated research were the tumor United States, China, Germany, and Italy. Finally, there has been a marked growth in studies on prognosis and patient survival, therapies, and treatments for glioblastoma. These findings reinforce the need for increased global resources to address glioblastoma, particularly in underdeveloped countries. Glioblastoma research's exponential growth reflects sustained interest in early diagnosis and patient survival.