Super selective intra-arterial cerebral infusion of modern chemotherapeutics after blood–brain barrier disruption: where are we now, and where we are going

Innovative solutions? Belzutifan therapy for hemangioblastomas in Von Hippel-Lindau disease: A systematic review and single-arm meta-analysis

BACKGROUND

Von Hippel-Lindau (VHL) disease is a rare autosomal dominant disorder that predisposes patients to develop multiple cysts and tumors, such as hemangioblastomas (HBs) and clear cell renal cell carcinoma (ccRCC), due to mutations in the VHL tumor suppressor gene. While treatment of HBs varies based on their characteristics and has improved patient survival, it still involves high morbidity and mortality, leading to ongoing debates and studies to refine therapy strategies. Recent developments include the emergence of Belzutifan, a novel inhibitor targeting hypoxia-inducible factor 2α (HIF-2α), which has shown promising results in ongoing trials, particularly for patients not immediately requiring surgery.

METHODS

This systematic review and meta-analysis aimed to comprehensively evaluate the efficacy and safety of Belzutifan for treating HBs associated with VHL disease. Search was conducted across Medline, Embase, Cochrane, and Web of Science databases. Statistical Analysis was performed, with proportions and 95 % confidence intervals. Statistical analyses were carried out using R Studio.

RESULTS

Ten studies were selected, comprising 553 patients. The population mean age was 40 (24-65), and 50 % of the population was formed by males. In terms of proportion, 6 analyses were performed: Disease Stability of 31 % [95 %CI:14 %-47 %; I2 = 2 %]; Disease Progression of 2 %[95 %CI:0 %-9 %; I2 = 0 %]; Partial Response of 75 % [95 %CI:54 %-96 %; I2 = 58 %]. Complete response of 1 % [95 %CI:0 %-7 %; I2 = 0 %];and Side effects, anemia 81 % rate [95 % CI:54 %-100 %; I2 = 94 %], and fatigue rate of 79 % [95 % CI:54 %-100 %;I2 = 94 %].

CONCLUSION

Results indicate that Belzutifan effectively stabilizes disease, reduces tumor progression, and achieves significant therapeutic responses, although side effects like anemia and fatigue were noted.

Overcoming Barriers in Glioblastoma-Advances in Drug Delivery Strategies

The world of cancer treatment is evolving rapidly and has improved the prospects of many cancer patients. Yet, there are still many cancers where treatment prospects have not (or hardly) improved. Glioblastoma is the most common malignant primary brain tumor, and even though it is sensitive to many chemotherapeutics when tested under laboratory conditions, its clinical prospects are still very poor. The blood-brain barrier (BBB) is considered at least partly responsible for the high failure rate of many promising treatment strategies. We describe the workings of the BBB during healthy conditions and within the glioblastoma environment. How the BBB acts as a barrier for therapeutic options is described as well as various approaches developed and tested for passing or opening the BBB, with the ultimate aim to allow access to brain tumors and improve patient perspectives.

Results from a first-in-human phase I safety trial to evaluate the use of a vascularized pericranial/temporoparietal fascial flap to line the resection cavity following resection of newly diagnosed glioblastoma

PURPOSE

The efficacy of systemic therapies for glioblastoma (GBM) remains limited due to the constraints of systemic toxicity and blood-brain barrier (BBB) permeability. Temporoparietal fascial flaps (TPFFs) and vascularized peri cranial flaps (PCF) are not restricted by the blood-brain barrier (BBB), as they derive their vascular supply from branches of the external carotid artery. Transposition of a vascularized TPFF or PCF along a GBM resection cavity may bring autologous tissue not restricted by the BBB in close vicinity to the tumor bed microenvironment, permit ingrowth of vascular channels fed by the external circulation, and offer a mechanism of bypassing the BBB. In addition, circulating immune cells in the vascularized flap may have better access to tumor-associated antigens (TAA) within the tumor microenvironment. We conducted a first-in-human Phase I trial assessing the safety of lining the resection cavity with autologous TPFF/PCF of newly diagnosed patients with GBM.

METHODS

12 patients underwent safe, maximal surgical resection of newly diagnosed GBMs, followed by lining of the resection cavity with a pedicled, autologous TPFF or PCF. Safety was assessed by monitoring adverse events. Secondary analysis of efficacy was examined as the proportion of patients experiencing progression-free disease (PFS) as indicated by response assessment in neuro-oncology (RANO) criteria and overall survival (OS). The study was powered to determine whether a Phase II study was warranted based on these early results. For this analysis, subjects who were alive and had not progressed as of the date of the last follow-up were considered censored and all living patients who were alive as of the date of last follow-up were considered censored for overall survival. For simplicity, we assumed that a 70% PFS rate at 6 months would be considered an encouraging response and would make an argument for further investigation of the procedure.

RESULTS

Median age of included patients was 57 years (range 46-69 years). All patients were Isocitrate dehydrogenase (IDH) wildtype. Average tumor volume was 56.6 cm3 (range 14-145 cm3). Resection was qualified as gross total resection (GTR) of all of the enhancing diseases in all patients. Grade III or above adverse events were encountered in 3 patients. No Grade IV or V serious adverse events occurred in the immediate post-operative period including seizure, infection, stroke, or tumor growing along the flap. Disease progression at the site of the original tumor was identified in only 4 (33%) patients (median 23 months, range 8-25 months), 3 of whom underwent re-operation. Histopathological analyses of those implanted flaps and tumor bed biopsy at repeat surgery demonstrated robust immune infiltrates within the transplanted flap. Importantly, no patient demonstrated evidence of tumor infiltration into the implanted flap. At the time of this manuscript preparation, only 4/12 (33%) of patients have died. Based on the statistical considerations above and including all 12 patients 10/12 (83.3%) had 6-month PFS. The median PFS was 9.10 months, and the OS was 17.6 months. 4/12 (33%) of patients have been alive for more than two years and our longest surviving patient currently is alive at 60 months.

CONCLUSIONS

This pilot study suggests that insertion of pedicled autologous TPFF/PCF along a GBM resection cavity is safe and feasible. Based on the encouraging response rate in 6-month PFS and OS, larger phase II studies are warranted to assess and reproduce safety, feasibility, and efficacy. TRIAL REGISTRATION NUMBER AND DATE OF REGISTRATION FOR PROSPECTIVELY REGISTERED TRIALS: ClinicalTrials.gov ID NCT03630289, dated: 08/02/2018.

Endovascular Applications for the Management of High-Grade Gliomas in the Modern Era

High-grade gliomas (HGGs) have a poor prognosis and are difficult to treat. This review examines the evolving landscape of endovascular therapies for HGGs. Recent advances in endovascular catheter technology and delivery methods allow for super-selective intra-arterial cerebral infusion (SSIACI) with increasing precision. This treatment modality may offer the ability to deliver anti-tumoral therapies directly to tumor regions while minimizing systemic toxicity. However, challenges persist, including blood-brain barrier (BBB) penetration, hemodynamic complexities, and drug-tumor residence time. Innovative adjunct techniques, such as focused ultrasound (FUS) and hyperosmotic disruption, may facilitate BBB disruption and enhance drug penetration. However, hemodynamic factors that limit drug residence time remain a limitation. Expanding therapeutic options beyond chemotherapy, including radiotherapy and immunobiologics, may motivate future investigations. While preclinical and clinical studies demonstrate moderate efficacy, larger randomized trials are needed to validate the clinical benefits. Additionally, future directions may involve endovascular sampling for peri-tumoral surveillance; changes in drug formulations to prolong residence time; and the exploration of non-pharmaceutical therapies, like radioembolization and photodynamic therapy. Endovascular strategies hold immense potential in reshaping HGG treatment paradigms, offering targeted and minimally invasive approaches. However, overcoming technical challenges and validating clinical efficacy remain paramount for translating these advancements into clinical care.

Potential of PSMA-targeting radioligand therapy for malignant primary and secondary brain tumours using super-selective intra-arterial administration: a single centre, open label, non-randomised prospective imaging study

BACKGROUND

The aim of this study was to provide quantitative evidence for the potential of PSMA-targeting radioligand therapy (RLT) as treatment approach for malignant brain tumours, and to explore whether tumour uptake could be enhanced by super-selective intra-arterial (ssIA)-administration.

METHODS

Ten patients (n = 5 high-grade glioma, n = 5 brain metastasis) received 1.5 MBq/kg [68Ga]Ga-PSMA-11 intravenously and, within 7 days, intra-arterially (i.e., selectively in tumour-feeding arteries), followed twice by PET-MRI at 90, 165 and 240 min post-injection. Patient safety was monitored for each procedure. Standardised uptake values (SUVs) were obtained for tumour, healthy-brain, salivary glands and liver. Tumour-to-salivary-gland (T/SG) and tumour-to-liver (T/L) uptake-ratios were calculated.

FINDINGS

No adverse events requiring study termination occurred. All patients showed uptake of [68Ga]Ga-PSMA-11 at the tumour site. Uptake was a median 15-fold higher following ssIA-administration (SUVmax median: 142.8, IQR: 102.8-245.9) compared to IV-administration (10.5, IQR:7.5-13.0). According to the bootstrap analysis, mean SUVmax after ssIA (168.8, 95% CI: 110.6-227.0) was well beyond the 95% confidence-interval of IV administration (10.5, 95% CI: 8.4-12.7). Uptake in healthy-brain was negligible, independent of administration route (SUVmean <0.1-0.1). Off-target uptake was comparable, resulting in more favourable T/SG- and T/L-ratios of 8.4 (IQR: 4.4-11.5) and 26.5 (IQR: 14.0-46.4) following ssIA, versus 0.5 (IQR: 0.4-0.7) and 1.8 (IQR: 1.0-2.7) for IV-administration.

INTERPRETATION

ssIA-administration is safe and leads to a median fifteen-fold higher radioligand uptake at the tumour site, therewith qualifying more patients for treatment and enhancing the potential of therapy. These results open new avenues for the development of effective RLT-based treatment strategies for patients with brain tumours.

FUNDING

Semmy Foundation.

Glioblastoma Therapy: Past, Present and Future

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

Targeted Glioma Therapy-Clinical Trials and Future Directions

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

Development of a rabbit human glioblastoma model for testing of endovascular selective intra-arterial infusion (ESIA) of novel stem cell-based therapeutics

BACKGROUND

Endovascular selective intra-arterial (ESIA) infusion of cellular oncotherapeutics is a rapidly evolving strategy for treating glioblastoma. Evaluation of ESIA infusion requires a unique animal model. Our goal was to create a rabbit human GBM model to test IA infusions of cellular therapies and to test its usefulness by employing clinical-grade microcatheters and infusion methods to deliver mesenchymal stem cells loaded with an oncolytic adenovirus, Delta-24-RGD (MSC-D24).

METHODS

Rabbits were immunosuppressed with mycophenolate mofetil, dexamethasone, and tacrolimus. They underwent stereotactic xenoimplantation of human GBM cell lines (U87, MDA-GSC-17, and MDA-GSC-8-11) into the right frontal lobe. Tumor formation was confirmed on magnetic resonance imaging, histologic, and immunohistochemistry analysis. Selective microcatheter infusion of MSC-D24 was performed via the ipsilateral internal carotid artery to assess model utility and the efficacy and safety of this approach.

RESULTS

Twenty-five rabbits were implanted (18 with U87, 2 MDA-GSC-17, and 5 MDA-GSC-8-11). Tumors formed in 68% of rabbits (77.8% for U87, 50.0% for MDA-GSC-17, and 40.0% for MDA-GSC-8-11). On MRI, the tumors were hyperintense on T2-weighted image with variable enhancement (evidence of blood brain barrier breakdown). Histologically, tumors showed phenotypic traits of human GBM including varying levels of vascularity. ESIA infusion into the distal internal carotid artery of 2 ml of MSCs-D24 (107 cells) was safe in the model. Examination of post infusion specimens documented that MSCs-D24 homed to the implanted tumor at 24 hours.

CONCLUSIONS

The intracranial immunosuppressed rabbit human GBM model allows testing of ESIA infusion of novel therapeutics (eg, MSC-D24) in a clinically relevant fashion.

Breaking Barriers in Neuro-Oncology: A Scoping Literature Review on Invasive and Non-Invasive Techniques for Blood-Brain Barrier Disruption

The blood-brain barrier (BBB) poses a significant challenge to drug delivery for brain tumors, with most chemotherapeutics having limited permeability into non-malignant brain tissue and only restricted access to primary and metastatic brain cancers. Consequently, due to the drug's inability to effectively penetrate the BBB, outcomes following brain chemotherapy continue to be suboptimal. Several methods to open the BBB and obtain higher drug concentrations in tumors have been proposed, with the selection of the optimal method depending on the size of the targeted tumor volume, the chosen therapeutic agent, and individual patient characteristics. Herein, we aim to comprehensively describe osmotic disruption with intra-arterial drug administration, intrathecal/intraventricular administration, laser interstitial thermal therapy, convection-enhanced delivery, and ultrasound methods, including high-intensity focused and low-intensity ultrasound as well as tumor-treating fields. We explain the scientific concept behind each method, preclinical/clinical research, advantages and disadvantages, indications, and potential avenues for improvement. Given that each method has its limitations, it is unlikely that the future of BBB disruption will rely on a single method but rather on a synergistic effect of a combined approach. Disruption of the BBB with osmotic infusion or high-intensity focused ultrasound, followed by the intra-arterial delivery of drugs, is a promising approach. Real-time monitoring of drug delivery will be necessary for optimal results.

Blood-Brain Barrier (BBB)-Crossing Strategies for Improved Treatment of CNS Disorders

Blood-brain barrier (BBB) is a special biological property of the brain neurovascular unit (including brain microvessels and capillaries), which facilitates the transport of nutrients into the central nervous system (CNS) and exchanges metabolites but restricts passage of blood-borne neurotoxic substances and drugs/xenobiotics into CNS. BBB plays a crucial role in maintaining the homeostasis and normal physiological functions of CNS but severely impedes the delivery of drugs and biotherapeutics into CNS for treatment of neurological disorders. A variety of technologies have been developed in the past decade for brain drug delivery. Most of these technologies are still in preclinical stage and some are undergoing clinical studies. Only a few have been approved by regulatory agencies for clinical applications. This chapter will overview the strategies and technologies/approaches for brain drug delivery and discuss some of the recent advances in the field.

Super-small zwitterionic micelles enable the improvement of blood-brain barrier crossing for efficient orthotopic glioblastoma combinational therapy

Glioblastoma multiforme (GBM) remains incurable in clinical, nanotechnology-based drug delivery strategies show promising perspective in alleviating GBM, while limited blood-brain-barrier (BBB) permeation, short blood half-live accompanied by the poor tumor accumulation and penetration, significantly restrict the therapeutic outcomes. Herein, a versatile super-small zwitterionic nano-system (MCB(S)) based on carboxybetaine (CB) zwitterion functionalized hyperbranched polycarbonate (HPCB) is developed to overcome the brain delivery challenges. After grafting with amino-functionalized IR780 (free IR780), the ultimate paclitaxel (PTX)-encapsulated micelles (MCB(S)-IR@PTX) are precisely activated by near-infrared (NIR) for accelerated drug release and effective combinational GBM therapy. Importantly, MCB(S)-IR@PTX with the crosslinked structure and CB zwitterion prolongs blood-circulation, and CB-zwitterion further facilitates BBB-traversing through betaine/γ-aminobutyric acid (GABA) transporter-1 (BGT-1) pathway. Combined with the benefit of super small-size, MCB(S)-IR@PTX highly accumulates at tumor sites and penetrates deeply, thus efficiently inhibiting tumor growth and strikingly improving survival time in U87MG orthotopic GBM-bearing mouse model. The ingenious nanoplatform furnishes a versatile strategy for delivering therapeutics into the brain and realizing efficient brain cancer therapy.

First in-human intrathecal delivery of bevacizumab for leptomeningeal spread from recurrent glioblastoma: rationale for a dose escalation trial

PURPOSE

To outline the dose rationale for the first in-human intrathecal delivery of bevacizumab for LMS of GBM.

METHODS

A 19-year-old female patient presented to Lenox Hill Hospital following thalamic GBM recurrence. She subsequently underwent two infusions of intra-arterial BEV (NCT01269853) and experienced a period of relative disease stability until progression in 2022. One month later, MRI disclosed diffuse enhancement representative of LMS of GBM. The patient subsequently underwent five cycles of IT BEV in mid-2022 (IND 162119). Doses of 25 mg, 37.5 mg, 50 mg, 50 mg, and 37.8 mg were delivered at two-week intervals between doses 1-4. The final 37.8 mg dose was given one day following her fourth dose, given that the patient was to be discharged, traveled several hours to our center, and was tolerating therapy well. Dosage was decreased due to the short interval between the final two treatments. Shortly after IT BEV completion, she received a third dose of IA BEV.

RESULTS

Our patient did not show any signs of serious adverse effects or dose limiting toxicities following any of the treatments. It is difficult to determine PFS due to the rapid progression associated with LMS of GBM and rapid timeframe of treatment.

CONCLUSION

LMS continues to be a devastating progression in many types of cancer, including GBM, and novel ways to deliver therapeutics may offer patients symptomatic and therapeutic benefits.

The first endovascular rat glioma model for pre-clinical evaluation of intra-arterial therapeutics

BACKGROUND

Several translational animal models have been described assessing intra-arterial (IA) treatments for malignant gliomas. We describe the first endovascular animal model that allows testing of IA drug delivery as a first-line treatment, which is difficult to do in actual patients. We report a unique protocol for vascular access and IA delivery in the rat model that, unlike prior reports, does not require direct puncture and opening of proximal cerebrovasculature which carries risk of ischemia in the animal brain post-delivery.

METHODS

Wistar rats underwent left femoral artery catherization with a Balt Magic 1.2F catheter or Marathon Flow directed 1.5F Microcatheter with an Asahi Chikai 0.008 micro-guidewire which was navigated to the left internal carotid artery under x-ray. 25% mannitol was administered to test blood brain barrier breakdown (BBBB). Additional rats were implanted with C6 glioma cells in the left frontal lobe. C6 Glioma-Implanted Rats (C6GRs) were monitored for overall survival and tumor growth. Tumor volumes from MRI images were calculated utilizing 3D slicer. Additional rats underwent femoral artery catheterization with Bevacizumab, carboplatin, or irinotecan injected into the left internal carotid artery to test feasibility and safety.

RESULTS

A successful endovascular access and BBBB protocol was established. BBBB was confirmed with positive Evans blue staining. 10 rats were successfully implanted with C6 gliomas with confirmed growths on MRI. Overall survival was 19.75 ± 2.21 days. 5 rats were utilized for the development of our femoral catheterization protocol and BBBB testing. With regards to IA chemotherapy dosage testing, control rats tolerated targeted 10 mg/kg of bevascizumab, 2.4 mg/kg of carboplatin, and 15 mg/kg of irinotecan IA ICA injections without any complications.

CONCLUSIONS

We present the first endovascular IA rat glioma model that allows selective catheterization of the intracranial vasculature and assessment of IA therapies for gliomas without need for access and sacrifice of proximal cerebrovasculature.

Preclinical validation of a novel therapeutic strategy for choroid plexus carcinoma

Choroid plexus carcinoma (CPC) is a rare infantile brain tumor with an aggressive clinical course that often leaves children with debilitating side effects due to aggressive and toxic chemotherapies. Development of novel therapeutical strategies for this disease have been extremely limited owing to the rarity of the disease and the paucity of biologically relevant substrates. We conducted the first high-throughput screen (HTS) on a human patient-derived CPC cell line (Children Cancer Hospital Egypt, CCHE-45) and identified 427 top hits highlighting key molecular targets in CPC. Furthermore, a combination screen with a wide variety of targets revealed multiple synergistic combinations that may pave the way for novel therapeutical strategies against CPC. Based on in vitro efficiency, central nervous system (CNS) penetrance ability and feasible translational potential, two combinations using a DNA alkylating or topoisomerase inhibitors in combination with an ataxia telangiectasia mutated and rad3 (ATR) inhibitor (topotecan/elimusertib and melphalan/elimusertib respectively) were validated in vitro and in vivo. Pharmacokinetic assays established increased brain penetrance with intra-arterial (IA) delivery over intra-venous (IV) delivery and demonstrated a higher CNS penetrance for the combination melphalan/elimusertib. The mechanisms of synergistic activity for melphalan/elimusertib were assessed through transcriptome analyses and showed dysregulation of key oncogenic pathways (e.g. MYC, mammalian target of rapamycin mTOR, p53) and activation of critical biological processes (e.g. DNA repair, apoptosis, hypoxia, interferon gamma). Importantly, IA administration of melphalan combined with elimusertib led to a significant increase in survival in a CPC genetic mouse model. In conclusion, this study is, to the best of our knowledge, the first that identifies multiple promising combinatorial therapeutics for CPC and emphasizes the potential of IA delivery for the treatment of CPC.

Biogenic Selenium Nanoparticles in Biomedical Sciences: Properties, Current Trends, Novel Opportunities and Emerging Challenges in Theranostic Nanomedicine

Selenium is an important dietary supplement and an essential trace element incorporated into selenoproteins with growth-modulating properties and cytotoxic mechanisms of action. However, different compounds of selenium usually possess a narrow nutritional or therapeutic window with a low degree of absorption and delicate safety margins, depending on the dose and the chemical form in which they are provided to the organism. Hence, selenium nanoparticles (SeNPs) are emerging as a novel therapeutic and diagnostic platform with decreased toxicity and the capacity to enhance the biological properties of Se-based compounds. Consistent with the exciting possibilities offered by nanotechnology in the diagnosis, treatment, and prevention of diseases, SeNPs are useful tools in current biomedical research with exceptional benefits as potential therapeutics, with enhanced bioavailability, improved targeting, and effectiveness against oxidative stress and inflammation-mediated disorders. In view of the need for developing eco-friendly, inexpensive, simple, and high-throughput biomedical agents that can also ally with theranostic purposes and exhibit negligible side effects, biogenic SeNPs are receiving special attention. The present manuscript aims to be a reference in its kind by providing the readership with a thorough and comprehensive review that emphasizes the current, yet expanding, possibilities offered by biogenic SeNPs in the biomedical field and the promise they hold among selenium-derived products to, eventually, elicit future developments. First, the present review recalls the physiological importance of selenium as an oligo-element and introduces the unique biological, physicochemical, optoelectronic, and catalytic properties of Se nanomaterials. Then, it addresses the significance of nanosizing on pharmacological activity (pharmacokinetics and pharmacodynamics) and cellular interactions of SeNPs. Importantly, it discusses in detail the role of biosynthesized SeNPs as innovative theranostic agents for personalized nanomedicine-based therapies. Finally, this review explores the role of biogenic SeNPs in the ongoing context of the SARS-CoV-2 pandemic and presents key prospects in translational nanomedicine.

Current approaches to facilitate improved drug delivery to the central nervous system

Although many pharmaceuticals have therapeutic potentials for central nervous system (CNS) diseases, few of these agents have been effectively administered. It is due to the fact that the blood-brain barrier (BBB) and the blood-cerebrospinal fluid barrier (BCSF) restrict them from crossing the brain to exert biological activity. This article reviews the current approaches aiming to improve penetration across these barriers for effective drug delivery to the CNS. These issues are summarized into direct systemic delivery and invasive delivery, including the BBB disruption and convection enhanced delivery. Furthermore, novel drug delivery systems used at the nanoscale, including polymeric nanoparticles, liposomes, nanoemulsions, dendrimers, and micelles are discussed. These nanocarriers could contribute to a breakthrough in the treatment of many different CNS diseases. However, further broadened studies are needed to assess the biocompatibility and safety of these medical devices.

Intra-arterial Bevacizumab for Posterior Fossa Hemangioblastoma

Hemangioblastoma (HB) is a rare, highly vascularized, and benign central nervous system (CNS) tumor. This vascularity is due to a high degree of signaling by vascular endothelial growth factor (VEGF). Consequently, anti-VEGF agents, such as bevacizumab, have been postulated and shown in a few cases to be effective in treating these tumors when surgical therapy is not feasible. Additionally, selective intra-arterial (IA) administration of bevacizumab has shown promise in treating other cancers such as glioblastoma (GBM). Here, we present the case of a 60-year-old female with a symptomatic posterior fossa HB where embolization and surgery were not feasible due to tumor location. She underwent selective IA treatment with bevacizumab, which led to tumor stability and symptomatic improvement. Bevacizumab has been used intravenously (IV) as a treatment for HB, however, its efficacy has not been well-established. This case demonstrates the potential viability of selective bevacizumab in HB, as demonstrated by symptomatic improvement and decreased tumor size on MRI. Further research is needed to demonstrate the specific efficacy of IA bevacizumab for CNS HB when surgery or other treatment modalities are not viable options.

A systematic review on intra-arterial cerebral infusions of chemotherapeutics in the treatment of glioblastoma multiforme: The state-of-the-art

Objective

To provide a comprehensive review of intra-arterial cerebral infusions of chemotherapeutics in glioblastoma multiforme treatment and discuss potential research aims. We describe technical aspects of the intra-arterial delivery, methods of blood-brain barrier disruption, the role of intraoperative imaging and clinical trials involving intra-arterial cerebral infusions of chemotherapeutics in the treatment of glioblastoma multiforme.

Method

159 articles in English were reviewed and used as the foundation for this paper. The Medline/Pubmed, Cochrane databases, Google Scholar, Scielo and PEDro databases have been used to select the most relevant and influential papers on the intra-arterial cerebral infusions of chemotherapeutics in the treatment of glioblastoma multiforme. Additionally, we have included some relevant clinical trials involving intra-arterial delivery of chemotherapeutics to other than GBM brain tumours.

Conclusion

Considering that conventional treatments for glioblastoma multiforme fall short of providing a significant therapeutic benefit, with a majority of patients relapsing, the neuro-oncological community has considered intra-arterial administration of chemotherapeutics as an alternative to oral or intravenous administration. Numerous studies have proven the safety of IA delivery of chemotherapy and its ability to ensure higher drug concentrations in targeted areas, simultaneously limiting systemic toxicity. Nonetheless, the scarcity of phase III trials prevents any declaration of a therapeutic benefit. Given that the likelihood of a single therapeutic agent which will be effective for the treatment of glioblastoma multiforme is extremely low, it is paramount to establish an adequate multimodal therapy which will have a synergistic effect on the diverse pathogenesis of GBM. Precise quantitative and spatial monitoring is necessary to guarantee the accurate delivery of the therapeutic to the tumour. New and comprehensive pharmacokinetic models, a more elaborate understanding of glioblastoma biology and effective methods of diminishing treatment-related neurotoxicity are paramount for intra-arterial cerebral infusion of chemotherapeutics to become a mainstay treatment for glioblastoma multiforme. Additional use of other imaging methods like MRI guidance during the procedure could have an edge over X-ray alone and aid in selecting proper arteries as well as infusion parameters of chemotherapeutics making the procedure safer and more effective.

Involvement of Resveratrol against Brain Cancer: A Combination Strategy with a Pharmaceutical Approach

A brain tumor (BT) is a condition in which there is growth or uncontrolled development of the brain cells, which usually goes unrecognized or is diagnosed at the later stages. Since the mechanism behind BT is not clear, and the various physiological conditions are difficult to diagnose, the success rate of BT is not very high. This is the central issue faced during drug development and clinical trials with almost all types of neurodegenerative disorders. In the first part of this review, we focus on the concept of brain tumors, their barriers, and the types of delivery possible to target the brain cells. Although various treatment methods are available, they all have side effects or toxic effects. Hence, in the second part, a correlation was made between the use of resveratrol, a potent antioxidant, and its advantages for brain diseases. The relationship between brain disease and the blood-brain barrier, multi-drug resistance, and the use of nanomedicine for treating brain disorders is also mentioned. In short, a hypothetical concept is given with a background investigation into the use of combination therapy with resveratrol as an active ingredient, the possible drug delivery, and its formulation-based approach.

Transient Opening of the Blood-Brain Barrier by Vasoactive Peptides to Increase CNS Drug Delivery: Reality Versus Wishful Thinking?

BACKGROUND

The blood-brain barrier inhibits the central nervous system penetration of 98% of small molecule drugs and virtually all biologic agents, which has limited progress in treating neurologic disease. Vasoactive peptides have been shown in animal studies to transiently disrupt the blood-brain barrier and regadenoson is currently being studied in humans to determine if it can improve drug delivery to the brain. However, many other vasoactive peptides could potentially be used for this purpose.

METHODS

We performed a review of the literature evaluating the physiologic effects of vasoactive peptides on the vasculature of the brain and systemic organs. To assess the likelihood that a vasoactive peptide might transiently disrupt the blood-brain barrier, we devised a four-tier classification system to organize the available evidence.

RESULTS

We identified 32 vasoactive peptides with potential blood-brain barrier permeabilityaltering properties. To date, none of these are shown to open the blood-brain barrier in humans. Twelve vasoactive peptides increased blood-brain barrier permeability in rodents. The remaining 20 had favorable physiologic effects on blood vessels but lacked specific information on permeability changes to the blood-brain barrier.

CONCLUSION

Vasoactive peptides remain an understudied class of drugs with the potential to increase drug delivery and improve treatment in patients with brain tumors and other neurologic diseases. Dozens of vasoactive peptides have yet to be formally evaluated for this important clinical effect. This narrative review summarizes the available data on vasoactive peptides, highlighting agents that deserve further in vitro and in vivo investigations.

Fluorination and Betaine Modification Augment the Blood-Brain Barrier-Crossing Ability of Cylindrical Polymer Brushes

Blood-brain barrier (BBB)-crossing ability of drugs is of paramount importance for the treatments of central nervous system diseases. However, the known methods for drug transport across the BBB are generally complicated and inefficient, and exhibit serious side effects in some cases. Herein, we report an exciting finding that fluorination and betaine modification can significantly augment the BBB-crossing ability of cylindrical polymer brushes (CPBs), which was demonstrated by the comparison with the CPBs modified with alkyl and poly(ethylene glycol) chains, respectively. We surmise that fluorination enhances the BBB penetration of the CPBs by increasing the hydrophobicity and reducing the surface energy, and betaine medication achieves this function via a betaine transporter BGT1 expressed on brain capillaries. By means of an in vitro BBB model, we demonstrated that the CPBs penetrated the BBB through transendothelial transport. This work provides a novel strategy for enhancing the BBB-crossing ability of nanomaterials.

Advances in local therapy for glioblastoma - taking the fight to the tumour

Despite advances in neurosurgery, chemotherapy and radiotherapy, glioblastoma remains one of the most treatment-resistant CNS malignancies, and the tumour inevitably recurs. The majority of recurrences appear in or near the resection cavity, usually within the area that received the highest dose of radiation. Many new therapies focus on combatting these local recurrences by implementing treatments directly in or near the tumour bed. In this Review, we discuss the latest developments in local therapy for glioblastoma, focusing on recent preclinical and clinical trials. The approaches that we discuss include novel intraoperative techniques, various treatments of the surgical cavity, stereotactic injections directly into the tumour, and new developments in convection-enhanced delivery and intra-arterial treatments.

Advances in Intraarterial Chemotherapy Delivery Strategies and Blood-Brain Barrier Disruption

Chemotherapeutics play a significant role in the management of most brain tumors. First pass effect, systemic toxicity, and more importantly, the blood-brain barrier pose significant challenges to the success of chemotherapy. Over the last 80 years, different techniques of intraarterial chemotherapy delivery have been performed in many studies but failed to become standard of care. The purpose of this article is to review the history of intraarterial drug delivery and osmotic blood-brain barrier disruption, identify the challenges for clinical translation, and identify future directions for these approaches.

Immunotherapeutic Approaches for Glioblastoma Treatment

Glioblastoma remains a challenging disease to treat, despite well-established standard-of-care treatments, with a median survival consistently of less than 2 years. In this review, we delineate the unique disease-specific challenges for immunotherapies, both brain-related and non-brain-related, which will need to be adequately overcome for the development of effective treatments. We also review current immunotherapy treatments, with a focus on clinical applications, and propose future directions for the field of GBM immunotherapy.

Safety of intra-arterial chemotherapy with or without osmotic blood–brain barrier disruption for the treatment of patients with brain tumors

Background

Intra-arterial administration of chemotherapy with or without osmotic blood–brain barrier disruption enhances delivery of therapeutic agents to brain tumors. The aim of this study is to evaluate the safety of these procedures.

Methods

Retrospectively collected data from a prospective database of consecutive patients with primary and metastatic brain tumors who received intra-arterial chemotherapy without osmotic blood–brain barrier disruption (IA) or intra-arterial chemotherapy with osmotic blood–brain barrier disruption (IA/OBBBD) at Oregon Health and Science University (OHSU) between December 1997 and November 2018 is reported. Chemotherapy-related complications are detailed per Common Terminology Criteria for Adverse Events (CTCAE) guidelines. Procedure-related complications are grouped as major and minor.

Results

4939 procedures (1102 IA; 3837 IA/OBBBD) were performed on 436 patients with various pathologies (primary central nervous system lymphoma [26.4%], glioblastoma [18.1%], and oligodendroglioma [14.7%]). Major procedure-related complications (IA: 12, 1%; IA/OBBBD: 27, 0.7%; P = .292) occurred in 39 procedures including 3 arterial dissections requiring intervention, 21 symptomatic strokes, 3 myocardial infarctions, 6 cervical cord injuries, and 6 deaths within 3 days. Minor procedure-related complications occurred in 330 procedures (IA: 41, 3.7%; IA/OBBBD: 289, 7.5%; P = .001). Chemotherapy-related complications with a CTCAE attribution and grade higher than 3 was seen in 359 (82.3%) patients.

Conclusions

We provide safety and tolerability data from the largest cohort of consecutive patients who received IA or IA/OBBBD. Our data demonstrate that IA or IA/OBBBD safely enhance drug delivery to brain tumors and brain around the tumor.

Blood-Brain Barrier in Brain Tumors: Biology and Clinical Relevance

The presence of barriers, such as the blood–brain barrier (BBB) and brain–tumor barrier (BTB), limits the penetration of antineoplastic drugs into the brain, resulting in poor response to treatments. Many techniques have been developed to overcome the presence of these barriers, including direct injections of substances by intranasal or intrathecal routes, chemical modification of drugs or constituents of BBB, inhibition of efflux pumps, physical disruption of BBB by radiofrequency electromagnetic radiation (EMP), laser-induced thermal therapy (LITT), focused ultrasounds (FUS) combined with microbubbles and convection enhanced delivery (CED). However, most of these strategies have been tested only in preclinical models or in phase 1–2 trials, and none of them have been approved for treatment of brain tumors yet. Concerning the treatment of brain metastases, many molecules have been developed in the last years with a better penetration across BBB (new generation tyrosine kinase inhibitors like osimertinib for non-small-cell lung carcinoma and neratinib/tucatinib for breast cancer), resulting in better progression-free survival and overall survival compared to older molecules. Promising studies concerning neural stem cells, CAR-T (chimeric antigen receptors) strategies and immunotherapy with checkpoint inhibitors are ongoing.

Modulating the Blood-Brain Barrier: A Comprehensive Review

The highly secure blood-brain barrier (BBB) restricts drug access to the brain, limiting the molecular toolkit for treating central nervous system (CNS) diseases to small, lipophilic drugs. Development of a safe and effective BBB modulator would revolutionise the treatment of CNS diseases and future drug development in the area. Naturally, the field has garnered a great deal of attention, leading to a vast and diverse range of BBB modulators. In this review, we summarise and compare the various classes of BBB modulators developed over the last five decades-their recent advancements, advantages and disadvantages, while providing some insight into their future as BBB modulators.

Status Quo and Trends of Intra-Arterial Therapy for Brain Tumors: A Bibliometric and Clinical Trials Analysis

Intra-arterial drug delivery circumvents the first-pass effect and is believed to increase both efficacy and tolerability of primary and metastatic brain tumor therapy. The aim of this update is to report on pertinent articles and clinical trials to better understand the research landscape to date and future directions. Elsevier's Scopus and ClinicalTrials.gov databases were reviewed in August 2021 for all possible articles and clinical trials of intra-arterial drug injection as a treatment strategy for brain tumors. Entries were screened against predefined selection criteria and various parameters were summarized. Twenty clinical trials and 271 articles satisfied all inclusion criteria. In terms of articles, 201 (74%) were primarily clinical and 70 (26%) were basic science, published in a total of 120 different journals. Median values were: publication year, 1986 (range, 1962-2021); citation count, 15 (range, 0-607); number of authors, 5 (range, 1-18). Pertaining to clinical trials, 9 (45%) were phase 1 trials, with median expected start and completion years in 2011 (range, 1998-2019) and 2022 (range, 2008-2025), respectively. Only one (5%) trial has reported results to date. Glioma was the most common tumor indication reported in both articles (68%) and trials (75%). There were 215 (79%) articles investigating chemotherapy, while 13 (65%) trials evaluated targeted therapy. Transient blood-brain barrier disruption was the commonest strategy for articles (27%) and trials (60%) to optimize intra-arterial therapy. Articles and trials predominately originated in the United States (50% and 90%, respectively). In this bibliometric and clinical trials analysis, we discuss the current state and trends of intra-arterial therapy for brain tumors. Most articles were clinical, and traditional anti-cancer agents and drug delivery strategies were commonly studied. This was reflected in clinical trials, of which only a single study had reported outcomes. We anticipate future efforts to involve novel therapeutic and procedural strategies based on recent advances in the field.

Cytoplasmic pressure maintains epithelial integrity and inhibits cell motility

Cytoplasmic pressure, a function of actomyosin contractility and water flow, can regulate cellular morphology and dynamics. In mesenchymal cells, cytoplasmic pressure powers cell protrusion through physiological three-dimensional extracellular matrices. However, the role of intracellular pressure in epithelial cells is relatively unclear. Here we find that high cytoplasmic pressure is necessary to maintain barrier function, one of the hallmarks of epithelial homeostasis. Further, our data show that decreased cytoplasmic pressure facilitates lamellipodia formation during the epithelial to mesenchymal transition (EMT). Critically, activation of the actin nucleating protein Arp2/3 is required for the reduction in cytoplasmic pressure and lamellipodia formation in response to treatment with hepatocyte growth factor (HGF) to induce EMT. Thus, elevated cytoplasmic pressure functions to maintain epithelial tissue integrity, while reduced cytoplasmic pressure triggers lamellipodia formation and motility during HGF-dependent EMT.

Repeated superselective intraarterial bevacizumab after blood brain barrier disruption for newly diagnosed glioblastoma: a phase I/II clinical trial

PURPOSE

Pre-clinical evidence suggests bevacizumab (BV) depletes the GBM peri-vascular cancer-stem cell niche. This phase I/II study assesses the safety and efficacy of repeated doses of superselective intra-arterial cerebral infusion (SIACI) of BV after blood-brain barrier disruption (BBBD).

METHODS

Date of surgery was day 0. Evaluated patients received repeated SIACI bevacizumab (15 mg/kg) with BBBD at days 30 ± 7, 120 ± 7, and 210 ± 7 along with 6 weeks of standard chemoradiation. Response assessment in neuro-oncology criteria and the Kaplan-Meier product-limit method was used to evaluate progression free and overall survival (PFS and OS, respectively).

RESULTS

Twenty-three patients with a median age of 60.5 years (SD = 12.6; 24.7-78.3) were included. Isocitrate dehydrogenase mutation was found in 1/23 (4%) patients. MGMT status was available for 11/23 patients (7 unmethylated; 3 methylated; 1 inconclusive). Median tumor volume was 24.0 cm3 (SD = 31.1, 1.7-48.3 cm³). Median PFS was 11.5 months (95% CI 7.7-25.9) with 6, 12, 24 and 60 month PFS estimated to be 91.3% (95% CI 69.5-97.8), 47.4% (26.3-65.9), 32.5% (14.4-52.2) and 5.4% (0.4-21.8), respectively. Median OS was 23.1 months (95% CI 12.2-36.9) with 12, 24, and 36 month OS as 77.3% (95% CI 53.6-89.9), 45.0% (22.3-65.3) and 32.1% (12.5-53.8), respectively.

CONCLUSIONS

Repeated dosing of IA BV after BBBD offers an encouraging outcome in terms of PFS and OS. Phase III trials are warranted to determine whether repeated IA BV combined with Stupp protocol is superior to Stupp protocol alone for newly diagnosed GBM.

The Evolving Role of Neurosurgical Intervention for Central Nervous System Tumors

Since its inception, greater than a century ago, neurosurgery has represented the fundamental trait-d'union between clinical management, scientific investigation, and therapeutic advancements in the field of brain tumors. During the years, oncological neurosurgery has evolved as a self-standing subspecialty, due to technical progress, equipment improvement, evolution of therapeutic paradigms, and the progressively crucial role that it plays in the execution of complex therapeutic strategies and modern clinical trials.

Improving Drug Delivery for Alzheimer's Disease Through Nose-to-Brain Delivery Using Nanoemulsions, Nanostructured Lipid Carriers (NLC) and in situ Hydrogels

Current treatments for Alzheimer's disease (AD) attenuate the progression of symptoms and aim to improve the patient's quality of life. Licensed medicines are mostly for oral administration and are limited by the difficulty in crossing the blood-brain barrier (BBB). Here in, the nasal route has been explored as an alternative pathway that allows drugs to be directly delivered to the brain via the nasal cavity. However, clearance mechanisms in the nasal cavity impair the delivery of drugs to the brain and limit their bioavailability. To optimize nose-to-brain delivery, formulations of lipid-based nanosystems, namely nanoemulsions and nanostructured lipid carriers (NLC), formulated in situ gelling hydrogels have been proposed as approaches for nose-to-brain delivery. These formulations possess characteristics that facilitate drug transport directly to the brain, minimizing side effects and maximizing therapeutic benefits. It has been recommended that the manufacture of these drug delivery systems follows the quality by design (QbD) approach based on nasal administration requirements. This review provides an insight into the current knowledge of the AD, highlighting the need for an effective drug delivery to the brain. Considering the mounting interest in the use of nanoemulsions and NLC for nose-to-brain delivery, a description of drug transport pathways in the nasal cavity and the application of these nanosystems and their in situ hydrogels through the intranasal route are presented. Relevant preclinical studies are summarised, and the future prospects for the use of lipid-based nanosystems in the treatment of AD are emphasized.

5-Aminolevulinic Acid-Shedding Light on Where to Focus

BACKGROUND

Surgical management of gliomas is predicated on "safe maximal resection" across all histopathologic grades because progression-free survival and overall survival are positively affected by the increasing extent of resection. Administration of the prodrug 5-aminolevulinic acid (5-ALA) induces tumor fluorescence with high specificity and sensitivity for malignant high-grade glioma (HGG). Fluorescence-guided surgery (FGS) using 5-ALA improves the extent of resection in the contrast-enhancing and nonenhancing tumor components in HGG. It has also shown preliminary usefulness in other central nervous system tumors, but with certain limitations.

METHODS

We review and discuss the state of 5-ALA FGS for central nervous system tumors and identify the limitations in its use as a guide for future clinical optimization.

RESULTS

5-ALA FGS provides maximum clinical benefits in the treatment of newly diagnosed glioblastoma. 5-ALA fluorescence specificity is limited in low-grade glioma, recurrent HGG, and non-glial tumors. Several promising intraoperative adjuncts to 5-ALA FGS have been developed to expand its indications and improve the clinical efficacy and usefulness of 5-ALA FGS.

CONCLUSIONS

5-ALA FGS improves the clinical outcomes in HGG. However, further optimization of the diagnostic performance and clinical use of 5-ALA FGS is necessary for low-grade glioma and recurrent HGG tumors. Neurosurgical oncology will benefit from the novel use of advanced technologies and intraoperative visualization techniques outlined in this review, such as machine learning, hand-held fibe-optic probes, augmented reality, and three-dimensional exoscope assistance, to optimize the clinical usefulness and operative outcomes of 5-ALA FGS.

Blood-brain barrier opening by intracarotid artery hyperosmolar mannitol induces sterile inflammatory and innate immune responses

Intracarotid arterial hyperosmolar mannitol (ICAHM) blood-brain barrier disruption (BBBD) is effective and safe for delivery of therapeutics for central nervous system malignancies. ICAHM osmotically alters endothelial cells and tight junction integrity to achieve BBBD. However, occurrence of neuroinflammation following hemispheric BBBD by ICAHM remains unknown. Temporal proteomic changes in rat brains following ICAHM included increased damage-associated molecular patterns, cytokines, chemokines, trophic factors, and cell adhesion molecules, indicative of a sterile inflammatory response (SIR). Proteomic changes occurred within 5 min of ICAHM infusion and returned to baseline by 96 h. Transcriptomic analyses following ICAHM BBBD further supported an SIR. Immunohistochemistry revealed activated astrocytes, microglia, and macrophages. Moreover, proinflammatory proteins were elevated in serum, and proteomic and histological findings from the contralateral hemisphere demonstrated a less pronounced SIR, suggesting neuroinflammation beyond regions of ICAHM infusion. Collectively, these results demonstrate ICAHM induces a transient SIR that could potentially be harnessed for neuroimmunomodulation.

Target specific tight junction modulators

Intercellular tight junctions represent a formidable barrier against paracellular drug absorption at epithelia (e.g., nasal, intestinal) and the endothelium (e.g., blood-brain barrier). In order to enhance paracellular transport of drugs and increase their bioavailability and organ deposition, active excipients modulating tight junctions have been applied. First-generation of permeation enhancers (PEs) acted by unspecific interactions, while recently developed PEs address specific physiological mechanisms. Such target specific tight junction modulators (TJMs) have the advantage of a defined specific mechanism of action. To date, merely a few of these novel active excipients has entered into clinical trials, as their lack in safety and efficiency in vivo often impedes their commercialisation. A stronger focus on the development of such active excipients would result in an economic and therapeutic improvement of current and future drugs.

Against the Resilience of High-Grade Gliomas: The Immunotherapeutic Approach (Part I)

The resilience of high-grade gliomas (HGGs) against conventional chemotherapies is due to their heterogeneous genetic landscape, adaptive phenotypic changes, and immune escape mechanisms. Innovative immunotherapies have been developed to counteract the immunosuppressive capability of gliomas. Nevertheless, further research is needed to assess the efficacy of the immuno-based approach. The aim of this study is to review the newest immunotherapeutic approaches for glioma, focusing on the drug types, mechanisms of action, clinical pieces of evidence, and future challenges. A PRISMA (Preferred Reporting Items for Systematic Review and Meta-Analysis)-based literature search was performed on PubMed/Medline and ClinicalTrials.gov databases using the keywords “active/adoptive immunotherapy,” “monoclonal antibodies,” “vaccine,” and “engineered T cell.”, combined with “malignant brain tumor”, “high-grade glioma.” Only articles written in English published in the last 10 years were selected, filtered based on best relevance. Active immunotherapies include systemic temozolomide, monoclonal antibodies, and vaccines. In several preclinical and clinical trials, adoptive immunotherapies, including T, natural killer, and natural killer T engineered cells, have been shown to be potential treatment options for relapsing gliomas. Systemic temozolomide is considered the backbone for newly diagnosed HGGs. Bevacizumab and rindopepimut are promising second-line treatments. Adoptive immunotherapies have been proven for relapsing tumors, but further evidence is needed.

Clinically Explored Virus-Based Therapies for the Treatment of Recurrent High-Grade Glioma in Adults

As new treatment modalities are being explored in neuro-oncology, viruses are emerging as a promising class of therapeutics. Virotherapy consists of the introduction of either wild-type or engineered viruses to the site of disease, where they exert an antitumor effect. These viruses can either be non-lytic, in which case they are used to deliver gene therapy, or lytic, which induces tumor cell lysis and subsequent host immunologic response. Replication-competent viruses can then go on to further infect and lyse neighboring glioma cells. This treatment paradigm is being explored extensively in both preclinical and clinical studies for a variety of indications. Virus-based therapies are advantageous due to the natural susceptibility of glioma cells to viral infection, which improves therapeutic selectivity. Furthermore, lytic viruses expose glioma antigens to the host immune system and subsequently stimulate an immune response that specifically targets tumor cells. This review surveys the current landscape of oncolytic virotherapy clinical trials in high-grade glioma, summarizes preclinical experiences, identifies challenges associated with this modality across multiple trials, and highlights the potential to integrate this therapeutic strategy into promising combinatory approaches.

Central nervous system delivery of molecules across the blood-brain barrier

Therapies targeting neurological conditions such as Alzheimer's or Parkinson's diseases are hampered by the presence of the blood-brain barrier (BBB). During the last decades, several approaches have been developed to overcome the BBB, such as the use of nanoparticles (NPs) based on biomaterials, or alternative methods to open the BBB. In this review, we briefly highlight these strategies and the most recent advances in this field. Limitations and advantages of each approach are discussed. Combination of several methods such as functionalized NPs targeting the receptor-mediated transcytosis system with the use of magnetic resonance imaging-guided focused ultrasound (FUS) might be a promising strategy to develop theranostic tools as well as to safely deliver therapeutic molecules, such as drugs, neurotrophic factors or antibodies within the brain parenchyma.

Treatment of Alzheimer's Disease and Blood-Brain Barrier Drug Delivery

Despite the enormity of the societal and health burdens caused by Alzheimer's disease (AD), there have been no FDA approvals for new therapeutics for AD since 2003. This profound lack of progress in treatment of AD is due to dual problems, both related to the blood-brain barrier (BBB). First, 98% of small molecule drugs do not cross the BBB, and ~100% of biologic drugs do not cross the BBB, so BBB drug delivery technology is needed in AD drug development. Second, the pharmaceutical industry has not developed BBB drug delivery technology, which would enable industry to invent new therapeutics for AD that actually penetrate into brain parenchyma from blood. In 2020, less than 1% of all AD drug development projects use a BBB drug delivery technology. The pathogenesis of AD involves chronic neuro-inflammation, the progressive deposition of insoluble amyloid-beta or tau aggregates, and neural degeneration. New drugs that both attack these multiple sites in AD, and that have been coupled with BBB drug delivery technology, can lead to new and effective treatments of this serious disorder.

Pharmacological Modulation of Blood-Brain Barrier Permeability by Kinin Analogs in Normal and Pathologic Conditions

The blood–brain barrier (BBB) is a major obstacle to the development of effective diagnostics and therapeutics for brain cancers and other central nervous system diseases. Peptide agonist analogs of kinin B1 and B2 receptors, acting as BBB permeabilizers, have been utilized to overcome this barrier. The purpose of the study was to provide new insights for the potential utility of kinin analogs as brain drug delivery adjuvants. In vivo imaging studies were conducted in various animal models (primary/secondary brain cancers, late radiation-induced brain injury) to quantify BBB permeability in response to kinin agonist administrations. Results showed that kinin B1 (B1R) and B2 receptors (B2R) agonists increase the BBB penetration of chemotherapeutic doxorubicin to glioma sites, with additive effects when applied in combination. B2R agonist also enabled extravasation of high-molecular-weight fluorescent dextrans (155 kDa and 2 MDa) in brains of normal mice. Moreover, a systemic single dose of B2R agonist did not increase the incidence of metastatic brain tumors originating from circulating breast cancer cells. Lastly, B2R agonist promoted the selective delivery of co-injected diagnostic MRI agent Magnevist in irradiated brain areas, depicting increased vascular B2R expression. Altogether, our findings suggest additional evidence for using kinin analogs to facilitate specific access of drugs to the brain.

Vascularized Temporoparietal Fascial Flap: A Novel Surgical Technique to Bypass the Blood-Brain Barrier in Glioblastoma

BACKGROUND

The major difficulty in treating glioblastoma stems from the intrinsic privileged nature of the brain. This complicates therapy, as many traditionally potent chemotherapeutics cannot access their target sites in the brain. Several techniques have been investigated to overcome this barrier and facilitate drug delivery. However, these techniques have inherent shortcomings related to the delivery system, the drug itself, or its bioactivity. Periosteal flaps and temporoparietal fascial flaps (TPFFs) are widely used options because they have predictable vasculature and a wide rotational arc. These flaps are not restricted by the blood-brain barrier, as they derive their vascular supply from branches of the external carotid artery, which can be readily identified with Doppler ultrasound. We hypothesized that transposition of a vascularized TPFF to the walls of a resected tumor surgical cavity may bring autologous tissue not restricted by the blood-brain barrier in close vicinity of the resected tumor bed microenvironment. This offers a nonselective, long-lasting gateway to target the residual tumor cells nesting in the brain adjacent to the tumor.

CASE DESCRIPTION

A 47-year-old, right-handed woman with newly diagnosed multifocal glioblastoma underwent excision of the tumor and TPFF placement. This illustrative case report represents the first case of the use of this novel surgical technique with radiologic follow-up.

CONCLUSIONS

The blood-brain barrier is identified as a major barrier for effective drug delivery in glioblastoma. This study demonstrates the feasibility of the TPFF technique to bypass this barrier and help facilitate the goal of improving drug delivery.