Nucleic acid-based therapeutic molecules including small interfering RNA (siRNA), microRNA(miRNA), antisense oligonucleotides (ASOs), messenger RNA (mRNA), and DNA-based gene therapy have tremendous potential for treating diseases in the central nervous system (CNS). However, achieving clinically meaningful delivery to the brain and particularly to target cells and sub-cellular compartments is typically very challenging. Mediating cell-specific delivery in the CNS would be a crucial advance that mitigates off-target effects and toxicities. In this review, we describe these challenges and provide contemporary evidence of advances in cellular and sub-cellular delivery using a variety of delivery mechanisms and alternative routes of administration, including the nose-to-brain approach. Strategies to achieve subcellular localization, endosomal escape, cytosolic bioavailability, and nuclear transfer are also discussed. Ultimately, there are still many challenges to translating these experimental strategies into effective and clinically viable approaches for treating patients.

Researchers from German institutions including the German Cancer Research Center and Mannheim University Medical Center have published encouraging long-term results from a clinical trial testing a novel peptide vaccine against gliomas, the most common malignant brain tumors. The vaccine targets a specific genetic mutation in the IDH1 enzyme that drives tumor growth and appears in the majority of these cancers. This mutation creates a neoepitope—a foreign protein structure that the immune system can recognize. In the Phase 1 NOA 16 trial involving 33 patients with high-grade astrocytomas, participants received the vaccine alongside standard treatment comprising surgery, radiation, and chemotherapy. After up to eight years of follow-up, 66 percent of patients remained alive and 42 percent showed no disease progression, significantly exceeding historical median survival times of 2.5 to 5 years. Patients with completely resected tumors demonstrated even higher survival rates. These results suggest the IDH1-targeted vaccine could fundamentally transform glioma treatment outcomes, offering new hope for patients with this previously difficult-to-treat cancer.

# Summary A comprehensive review published in Frontiers in Oncology by Wu, Liu, Lv, Ming, Song, and Chu examines lipid metabolic plasticity in glioblastoma, the most aggressive form of brain cancer. The study investigates how glioblastoma cells reprogram their lipid metabolism to survive and resist therapeutic interventions. The research explores the mechanisms underlying metabolic plasticity, demonstrating how tumor cells dynamically switch between different metabolic states to adapt to changing microenvironmental conditions. The authors analyze how these metabolic adaptations reshape the tumor microenvironment, affecting immune cell infiltration and creating immunosuppressive conditions. The review identifies lipid metabolism reprogramming as a critical driver of therapeutic resistance in glioblastoma, presenting significant obstacles to current treatment strategies. By elucidating these metabolic mechanisms and their relationship to tumor microenvironment remodeling, the study highlights novel therapeutic opportunities targeting lipid metabolism as a promising approach to overcome resistance and improve clinical outcomes for glioblastoma patients. This work advances understanding of how metabolic flexibility contributes to glioblastoma's aggressive phenotype and treatment evasion.

FDA-approved oncolytic herpes simplex virus-1 (oHSV) represents a promising viro-immunotherapy for solid tumors, yet its clinical efficacy is often limited by tumor adaptations including immune suppression and enhanced aggressiveness. Researchers investigating the molecular mechanisms of oHSV resistance discovered that the therapy activates insulin-like growth factor 1 receptor (IGF1R) signaling, promoting tumor proliferation and therapeutic resistance. The study evaluated combining IGF1R blockade with oHSV and radiotherapy (RTx) across breast cancer and glioblastoma models. While IGF1R inhibition alone showed limited benefit, combining it with oHSV produced modest but significant cytotoxic improvements in both in vitro and xenograft models. Notably, dual oHSV and RTx co-treatment activated both IGF1R and YAP1 signaling pathways in resistant cells, identifying the IGF1R/YAP1 axis as a critical resistance mechanism. The triple combination of oHSV, RTx, and IGF1R blockade achieved synergistic anti-tumor effects, suppressed YAP1 expression, and significantly enhanced survival in orthotopic tumor models. These findings establish the IGF1R/YAP1 axis as a key resistance driver and provide compelling rationale for clinical development of this triple-combination strategy to improve outcomes in breast cancer and glioblastoma patients.

This research by Egiroh Omene examines metabolic competition within the glioblastoma tumor microenvironment and its role in immune exclusion. The study investigates how glucose, glutamine, and lactate metabolism shape immune cell function and tumor-associated macrophage activity in glioblastoma, an aggressive brain cancer with notoriously poor immunotherapy responses. The analysis reveals that cancer cells compete with immune cells for critical metabolic substrates, creating a nutrient-depleted microenvironment that suppresses anti-tumor immunity. Specifically, the research identifies glucose glycolysis, glutamine metabolism, and lactate accumulation as key mechanisms driving immune cell dysfunction and exclusion from tumors. The findings highlight metabolic reprogramming as a promising therapeutic strategy to restore immune function. By targeting these metabolic pathways through pharmacological interventions, researchers propose reversing immune suppression and enhancing immunotherapy efficacy. This work addresses a fundamental barrier to glioblastoma treatment, suggesting that combining metabolic modulation with conventional immunotherapies could improve patient outcomes by reshaping the hostile tumor microenvironment to support immune activation.

Researchers conducted a Phase 1 clinical trial investigating personalized multivalent neoantigen DNA vaccination as an adjuvant treatment for glioblastoma, an aggressive brain cancer. Following initial surgical resection, patients received the personalized neoantigen vaccine designed to stimulate immune responses against tumor-specific mutations. The trial evaluated immunogenicity, progression-free survival, and overall survival while monitoring for dose-limiting toxicity and serious adverse events, including fatal infections. Results demonstrated that the DNA vaccination approach induced activation of peripheral T cells and generated robust immune responses. The study identified long-term survivors among participants and showed clinical activity of the personalized therapeutic vaccine in combination with standard glioblastoma treatment. This research is significant because it explores personalized immunotherapy tailored to individual tumor mutations, potentially offering a more targeted approach to treating one of the most lethal cancers. The findings support further investigation into neoantigen-based DNA immunization as an adjuvant strategy to improve outcomes in glioblastoma patients and validate the broader potential of personalized cancer vaccines in oncology.

Researchers at the University of Virginia Comprehensive Cancer Center have developed an innovative therapeutic approach to treat glioblastoma, the most aggressive and deadliest form of brain cancer. Led by Dr. Roger Abounader, the team identified microRNAs capable of simultaneously suppressing multiple malfunctioning genes that drive glioblastoma formation and progression. The breakthrough uses a combination of brain-penetrating nanoparticles, focused ultrasound waves, and microbubbles to deliver these microRNAs across the blood-brain barrier, a natural protective mechanism that typically prevents anticancer drugs from reaching brain tumors. Published in the Journal of Clinical Investigation, this approach addresses a critical challenge in glioblastoma treatment: the inability to target multiple cancer-promoting molecules simultaneously due to drug toxicity concerns. With glioblastoma claiming over 13,000 American lives annually and currently treated through surgery, radiation, and chemotherapy with limited success, this microRNA-based strategy offers potential for more effective therapies. Abounader's team aims to advance these findings toward clinical trials, potentially transforming treatment options for glioblastoma and other brain tumors.

Glioblastoma (GBM) remains one of the most aggressive brain cancers, with approximately 3-5 cases per 100,000 people diagnosed annually. In Germany, over 7,000 malignant central nervous system tumors were recorded in 2022, with glioblastoma incidence ranging from 1.6 to 4.3 per 100,000 depending on demographics. Despite its relatively low incidence, GBM carries a devastating prognosis, with median overall survival under current standard care—surgery, radiation, and chemotherapy—remaining between 10-15 months and five-year survival rates below 10 percent. A large German retrospective study of over 40,000 cases from 1999-2014 confirmed median overall survival of 10.0 months, though modest improvements in two-year survival rates were noted over time. In response to these poor outcomes, immuno-oncology emerges as a promising therapeutic approach. This strategy leverages the patient's immune system to selectively target cancer cells while preserving healthy tissue by training immune cells to distinguish malignant from normal tissue. Unlike conventional treatments, immunotherapy offers potential to improve survival outcomes and prevent relapse in primary brain tumors, making it particularly appealing for GBM patients seeking advanced treatment options.

Glioblastoma multiforme (GBM), the most common and aggressive primary brain tumor in adults accounting for 15% of cases, carries a dismal prognosis with a median survival of 14.6 months and a 5-year survival rate of only 3.3%, despite standard treatments including surgical resection, ionizing radiation, and temozolomide. The Cancer Genome Atlas characterized distinct GBM transcriptional subtypes and identified an epigenetic subtype (G-CIMP) associated with IDH1 mutations. Although recurrent mutations in EGF receptor and PDGF receptor A have been discovered, neither has proven therapeutically promising. The article explores therapeutic targeting of tumor-associated macrophages as a potential approach to overcome current treatment limitations. Key challenges include the blood-brain barrier's impermeability to most pharmaceutical agents and GBM's substantial intratumoral heterogeneity, which may prevent single-agent efficacy. Understanding and targeting the immunological microenvironment, particularly macrophage involvement, represents a critical avenue for developing more effective therapeutic strategies against this devastating disease.

Recent discoveries of meningeal lymphatic vessels (MLVs) have fundamentally transformed understanding of immune regulation in the central nervous system, challenging the traditional view of the brain as an immune-privileged organ. This comprehensive review examines the critical intersection between MLVs and glioblastoma (GBM), the most aggressive primary brain tumor classified as WHO grade 4. Despite advances in neurosurgical techniques and adjuvant therapies, GBM remains therapeutically challenging, with a median overall survival of only 14.6 months, primarily due to its highly immunosuppressive microenvironment and resistance to conventional and immunotherapy approaches. The emerging evidence indicates that MLVs play pivotal roles in CNS immune surveillance, cerebrospinal fluid drainage, and solute clearance—all directly connected to GBM pathophysiology. This review systematically analyzes bidirectional interactions between MLVs and GBM, particularly regarding antigen transport, T cell activation, and tumor dissemination. The authors evaluate promising therapeutic strategies targeting MLVs through lymphangiogenic stimulation and alternative immune modulation routes, including novel drug delivery pathways. These approaches represent innovative opportunities to enhance anti-tumor immunity and potentially establish next-generation treatment paradigms for GBM management.

Researchers have developed an engineered oncolytic virus designed to overcome resistance to immunotherapy in cancer treatment. The virus coexpresses a PD-L1 inhibitor alongside GM-CSF, enabling it to secrete the inhibitor systemically to block PD-L1 expression on both tumor and immune cells. When administered via intratumoral injection, this approach successfully neutralizes PD-L1-mediated immunosuppression during both the priming and effector phases of immune response, activating tumor neoantigen-specific T cell responses against mutations. The treatment effectively rejected both directly injected tumors and distant metastases in the study. This innovation addresses a critical clinical problem: while tumor neoantigens derived from mutations can theoretically trigger immune responses, the immunosuppressive tumor microenvironment typically blocks these responses through checkpoint molecules like PD-L1. Although PD-1/PD-L1 blockade has demonstrated efficacy in certain cancers including melanoma and lung carcinoma, the majority of cancer patients remain resistant to these therapies. This engineered oncolytic virus represents a promising individualized therapeutic option, particularly for patients who have failed conventional checkpoint inhibitor treatment, by combining viral-mediated tumor destruction with enhanced neoantigen-specific immunity.

Researchers from Chinese medical institutions conducted a comprehensive review examining how inflammation functions as a central regulator of immunotherapy efficacy in head and neck squamous cell carcinoma (HNSCC). The study analyzed the complex interplay between chronic inflammatory signals, immune cell behavior, and tumor biology to explain immunotherapy response variability. Key findings revealed that inflammatory pressure reprograms critical immune cells—including macrophages, regulatory T cells, exhausted CD8+ T cells, and dendritic cell subsets—transforming them from tumor-suppressing sentinels into promoters of tumor growth and invasion. The researchers identified inflammation-driven signaling pathways including NF-κB/STAT3, IL-6/TNFα, TGF-β, and PI3K-4EBP1-SOX2 as orchestrators of immunotherapy response. They catalogued biomarkers such as PD-L1, CD163/CD68 ratios, LAMP3, and CD44 isoforms that provide enhanced patient stratification when analyzed at single-cell and spatial resolution. This framework is significant because it demonstrates how understanding inflammation-induced immune cell plasticity and associated molecular pathways enables better prediction of checkpoint blockade success or failure, potentially improving treatment outcomes for HNSCC patients.

In situ cancer vaccination, also known as intratumoral immunotherapy, represents a promising approach that transforms tumors into personalized vaccine platforms by leveraging the tumor itself as an antigen source. Unlike conventional tumor-associated antigen or personalized neoantigen vaccines requiring predefined targets and complex manufacturing, this strategy exposes the tumor's complete antigenic repertoire—including tumor-associated antigens, neoantigens, post-translationally modified epitopes, and viral antigens—within their native context. This broad exposure triggers robust polyclonal cytotoxic T-cell responses and epitope spreading while reducing immune escape from tumor heterogeneity. The approach coordinates multiple immune mechanisms through programmed cell death pathways including immunogenic apoptosis, pyroptosis, necroptosis, and ferroptosis, which release tumor antigens and danger-associated molecular patterns promoting dendritic-cell activation and durable T-cell responses. Incorporation of potent adjuvants and advanced delivery platforms enhances immune activation and remodels the immunosuppressive tumor microenvironment. Despite advantages, clinical translation faces challenges including inconsistent immunogenic cell death induction, suboptimal intratumoral therapeutic retention, and T-cell infiltration barriers. Recent advances in nanomedicine delivery systems, microenvironmental modulation, and combinatorial strategies with immune checkpoint blockade are addressing these limitations, positioning in situ cancer vaccination as a broadly applicable, patient-tailored immunotherapy capable of generating durable systemic antitumor immunity.

The NOA16 trial evaluated the safety and immunogenicity of IDH1-vac, a peptide vaccine targeting the IDH1-R132H mutation found in most astrocytomas, in 33 patients with newly diagnosed grade III and IV IDH1-mutant astrocytomas. The vaccine was integrated into standard treatment protocols. Long-term follow-up data reveal impressive clinical outcomes, with 8-year progression-free and overall survival rates of 42 and 66 percent respectively. Grade IV astrocytoma patients achieved a median overall survival of 106.1 months, substantially exceeding the published range of 31.6 to 56.4 months for this population. Sustained antibody responses to IDH1-R132H correlated with favorable long-term outcomes. Notably, IDH1-vac-induced T cell responses were detected in brain lesions associated with pseudoprogression, while absent in patients experiencing early progressive disease. These compelling long-term results support advancing IDH1-vac into a randomized phase 2 trial for newly diagnosed IDH-mutant astrocytomas, representing a promising immunotherapeutic approach for this challenging brain tumor population.

This article reviews significant glioblastoma research developments from mid-2026, the thirty-seventh installment in a bimonual series tracking potential treatments for this aggressive brain tumor. A pivotal finding centers on the BT008NA study, sponsored by Insightec and published in Lancet Oncology, which evaluated focused ultrasound combined with microbubbles to transiently open the blood-brain barrier—a major obstacle preventing chemotherapy from reaching tumors. In this international phase 1/2 trial, patients receiving monthly focused-ultrasound treatments with temozolomide achieved median progression-free survival of nearly 14 months and overall survival exceeding 30 months, compared to 8 and 19 months respectively in standard-treatment controls. Though the technique did not directly quantify drug delivery to tumors, results demonstrated feasibility, safety, and efficacy, positioning ultrasound-mediated barrier opening as a platform potentially extensible to immunotherapies and other agents, with ongoing studies combining the approach with bispecific antibodies and bevacizumab. Additionally, a phase 1 gene therapy study published in Nature Medicine investigated interferon-α delivered directly to the tumor microenvironment, targeting glioblastoma's immunologically "cold" characteristics and myeloid-driven immunosuppression.

Glioblastoma remains a highly lethal primary brain tumor with poor prognosis despite aggressive multimodal treatment including surgery, radiotherapy, and chemotherapy. The primary obstacle to therapeutic success is an intensely immunosuppressive tumor microenvironment characterized by immune exclusion, defective antigen presentation, and profound T-cell dysfunction. Multiple cellular components, including tumor-associated macrophages, microglia, myeloid-derived suppressor cells, and regulatory T cells, collectively establish this suppressive niche through cytokine signaling, metabolic restriction, and checkpoint ligand expression. Key molecular pathways including TGF-β/SMAD, IL-10/STAT3, and hypoxia-HIF-1α signaling converge to prevent effective antitumor immunity. This review examines the cellular and molecular mechanisms underlying immune suppression in glioblastoma and evaluates emerging therapeutic approaches such as myeloid reprogramming, checkpoint blockade combinations, and metabolic interventions designed to convert immune-excluded tumors into immune-responsive disease.

Researchers have developed a novel ultrasound-triggered chemotherapy approach that significantly extends survival in glioblastoma, an aggressive brain cancer. Led by Joshua Antonio Whiting and colleagues, this study demonstrates the potential of combining targeted drug delivery with ultrasound activation in a genetically engineered tumor model. The innovation addresses a critical challenge in glioblastoma treatment by enabling localized chemotherapy release directly at the tumor site, potentially reducing systemic toxicity while improving therapeutic efficacy. This advancement represents a promising therapeutic strategy for enhancing survival outcomes in this notoriously difficult-to-treat malignancy.

Glioblastoma multiforme (GBM) represents one of the most aggressive brain cancers, with annual incidence rates of 3–5 per 100,000 population globally. Current standard treatment protocols combining surgery, radiation, and chemotherapy yield disappointing outcomes, with median overall survival of only 10–15 months and 5-year survival rates below 10 percent. Immunotherapy emerges as a promising therapeutic avenue, leveraging the patient's immune system to selectively target malignant cells while preserving healthy tissue. This innovative approach seeks to reprogram immune cells to distinguish between cancerous and normal brain tissue, potentially circumventing conventional treatment limitations and reducing relapse incidence. Given GBM's poor prognosis, immunological interventions represent a critical advancement in improving patient outcomes and survival prospects.

Recent clinical trials show that CAR T cell therapies can initially blunt tumor growth in patients with glioblastoma (GBM). However, therapeutic efficacy remains limited by the immunosuppressive tumor microenvironment and restricted immune cell trafficking across the blood-brain barrier (BBB). To counteract these challenges, we have utilized the oncolytic adenovirus (OV) Ad5-Δ24-RGD as a platform to overexpress a bispecific T cell engager (BiTE) targeting both CD3 on T cells and the GBM-specific tumor associated antigen IL-13Rα2. We first demonstrated that OV-BiTE can significantly increase the recruitment of T cells to GBM, both in vitro and in vivo.

Glioblastoma (GBM) represents one of the prototypical immune-cold tumors, characterized by profound immune suppression, T-cell exclusion, low neoantigen burden, and a highly immunosuppressive myeloid-dominant tumor microenvironment (TME). Despite advances in immunotherapy, including immune checkpoint blockade (ICB), CAR-T cells, and cancer vaccines, clinical benefits remain limited. This review synthesizes emerging evidence on multi-modal strategies aimed at reprogramming the cold TME into an immunologically active state. We highlight innate immune agonists, oncolytic virotherapy, precision nanomedicine, metabolic modulation, and radiotherapy-immune synergies. We further propose an integrated framework combining spatial immunomics, targeted delivery technology, and TME-specific engineering to overcome the therapeutic bottlenecks of GBM.