Survival outcomes and safety of carmustine wafers in the treatment of high-grade gliomas: a meta-analysis

Targeting the glioblastoma resection margin with locoregional nanotechnologies

Surgical resection is the first stage of treatment for patients diagnosed with resectable glioblastoma and is followed by a combination of adjuvant radiotherapy and systemic single-agent chemotherapy, which is typically commenced 4-6 weeks after surgery. This delay creates an interval during which residual tumour cells residing in the resection margin can undergo uninhibited proliferation and further invasion, even immediately after surgery, thus limiting the effectiveness of adjuvant therapies. Recognition of the postsurgical resection margin and peri-marginal zones as important anatomical clinical targets and the need to rethink current strategies can galvanize opportunities for local, intraoperative approaches, while also generating a new landscape of innovative treatment modalities. In this Perspective, we discuss opportunities and challenges for developing locoregional therapeutic strategies to target the glioblastoma resection margin as well as emerging opportunities offered by nanotechnology in this clinically transformative setting. We also discuss how persistent barriers to clinical translation can be overcome to offer a potential path forward towards broader acceptability of such advanced technologies.

Nanofibers in Glioma Therapy: Advances, Applications, and Overcoming Challenges

Despite relentless effort to study glioma treatment, the prognosis for glioma patients remains poor. The main obstacles include the high rate of recurrence and the difficulty of passing the blood-brain barrier (BBB) for therapeutic drugs. Nanomaterials owing to their special physicochemical properties have been used in a wide range of fields thus far. The nanodrug delivery system (NDDS) with the ability of crossing the BBB, targeting glioma site, maintaining drug stability and controlling drug release, has significantly enhanced the anti-tumor therapeutic effect, improving the prognosis of glioma patients. Aligned nanofibers (NFs) are ideal materials to establish in vitro models of glioma microenvironment (GME), enabling the exploration of the mechanism of glioma cell migration and invasion to discover novel therapeutic targets. Moreover, NFs are now widely used in glioma applications such as radiotherapy, phototherapy, thermotherapy and immunotherapy. Despite the absolute dominance of NFs in anti-glioma applications, there are still some problems such as the further optimization of NDDS, and the impact of interactions between nanofibers and the protein corona (PC) on glioma therapy. This paper will shed light on the latest glioma applications of NFs in drug delivery systems and mimicking the tumor microenvironment (TME), and discuss how to further optimize the NDDS and eliminate or utilize the nanomedicine-PC interactions.

Nanotechnology Driven Lipid and Metalloid Based Formulations Targeting Blood-Brain Barrier (3B) for Brain Tumor

 The evolution of nanotechnology-driven lipid and metalloid-based nanoformulations has garnered significant attention for developing effective drug delivery systems with position/time precision and efficacy. This study focuses on challenges of blood-brain barrier (BBB) and their pivotal role in drug targeting in chronic diseases such as brain tumors (BTs). These formulations encapsulate therapeutic agents within lipidic matrices, enhancing drug solubility, bioavailability, and targeted delivery. The diverse lipid materials used in these nanoformulations highlight their biocompatibility and versatility, covering a wide range of drugs. Emphasis is placed on metal nanoparticles, liposomes, ethosomes, quantum dots, carbon nanotubes, nanorobots, and micelles. The analysis explores their drug loading, stability, release characteristics, and bioavailability modulation. It also delves into the enhanced-permeability and retention (EPR) effect, crucial for passive targeting of tumors. Recent nanocarrier systems enable better penetration of therapeutic compounds through the BBB, addressing treatment failures in invasive BTs.This review highlights the latest nanotechnology developments and potential therapeutic approaches, serving as a valuable resource for researchers, clinicians, and pharmaceutical scientists.

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.

Effect of Intraoperative Ventricular Opening on Recurrence Patterns Following Bis-Chloroethyl-Nitrosourea Wafer Implantation for Newly Diagnosed Glioblastoma

OBJECTIVE

To evaluate the effect of ventricular opening (VO) on recurrence patterns in patients with newly diagnosed glioblastoma (GBM) treated with bis-chloroethyl-nitrosourea (BCNU) wafer implantation.

METHODS

This single-center retrospective study included 40 patients with newly diagnosed GBM who received BCNU wafer implantation after tumor resection between March 2013 and February 2022. The patients were categorized into two groups based on whether VO occurred during the GBM resection. While 18 patients had VO, 22 did not have VO. In cases with VO, the ventricular wall defect is closed with gelatin or oxidized regenerated cellulose and fibrin glue before BCNU wafer implantation. Recurrence patterns-classified as local, diffuse, distant, or multifocal-and time to recurrence were compared between patients with and without VO.

RESULTS

The median follow-up period for the entire cohort was 32.2 months (interquartile range, 16.7-38 months). Median survival time was comparable between patients with VO and patients without VO (38 vs. 26 months, p=0.53). Recurrence occurred in 31/40 patients (77.5%) in entire cohort. The incidence of recurrence was comparable between patients with VO and patients without VO (14 [77.8%] vs. 17 [77.3%], p=1.0). No significant differences were seen between the two groups in time to recurrence (p=0.59) or recurrence patterns (p=0.35).

CONCLUSION

Ventricular opening during surgery with BCNU wafer implantation does not seem to influence the recurrence patterns. Ventricular opening does not induce distant recurrence if appropriate ventricular closure is performed.

Neurosurgical application of olaparib from a thermo-responsive paste potentiates DNA damage to prolong survival in malignant glioma

BACKGROUND

There is increased pan-cancer specific interest in repurposing the poly adenosine diphosphate-ribose polymerase-1 (PARP-1) inhibitor, olaparib, for newly diagnosed or recurrent isocitrate dehydrogenase wild type glioblastoma. We explore whether intra-cavity delivery of olaparib confers a survival benefit in a pre-clinical high-grade glioma model.

METHODS

Primary tumor RNA sequencing data was used to determine PARP-1 as a target in the glioblastoma infiltrative margin. We assessed radiosensitization conferred by olaparib alone and concomitant to genotoxic insults in vitro using clonal growth assays, cell cycle analysis and immunocytochemistry, and in vivo upon post-surgical delivery from a temperature-sensitive polymeric paste.

RESULTS

RNA-sequencing confirmed PARP-1 as a viable therapy target in glioblastoma infiltrative disease. Acute exposure of glioma cells to olaparib impaired proliferation and induced late-stage apoptosis associated with DNA damage in vitro, potentiated by radiation. Using high-grade glioma orthotopic allografts, a long-term overall survival benefit was observed upon interstitial olaparib delivery concomitant with radiotherapy, compared to systemic olaparib and standard glioblastoma treatment. Combined delivery of olaparib with either temozolomide or etoposide increased long-term survival, suggestive of olaparib functioning as DNA damage sensitizer.

CONCLUSIONS

Collectively, our data support a rationale for localized olaparib delivery concomitant with the current clinical regimen for malignant glioma treatment.

Is Carmustine Wafer Implantation in Progressive High-Grade Gliomas a Relevant Therapeutic Option? Complication Rate, Predictors of Complications and Onco-Functional Outcomes in a Series of 53 Cases

Background/Objectives: The aim was to determine the complication rate and the predictors of complications and survival in high-grade glioma surgically managed at progression with implantation of Carmustine wafers. Methods: A retrospective series of 53 consecutive patients operated on between 2017 and 2022 was built. Results: The median age was 55 ± 10.9 years. The rates of global and infectious complications were 35.8% and 18.9%, respectively. In multivariate analysis, patients with a preoperative neurological deficit were more prone to develop a postoperative complication (HR = 5.35 95% CI 1.49-19.26, p = 0.01). No predictor of infectious complication was identified. In the grade 4 glioma subgroup (n = 44), progression-free and overall survival (calculated starting from the reresection) reached 3.95 months, 95% CI 2.92-5.21 and 11.51 months, 95% CI 9.11-17.18, respectively. Preoperative KPS > 80% (HR = 0.97 95% CI 0.93-0.99, p = 0.04), Gross Total Resection (HR = 0.38 95% CI 0.18-0.80, p = 0.01), and 3-month postoperative KPS > 80% (HR = 0.35 95% CI 0.17-0.72, p = 0.004) were predictors of prolonged overall survival. Conclusions: Surgical resection is a relevant option in high-grade gliomas at progression, especially in patients with a preoperative KPS > 80%, without preoperative neurological deficit, and amenable to complete resection. In patients elected for surgery, Carmustine wafer implantation is associated with a high rate of complications. It is consequently critical to closely monitor the patients for whom this option is chosen.

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.

Local Delivery of Irinotecan to Recurrent GBM Patients at Reoperation Offers a Safe Route of Administration

Glioblastomas are impossible to completely resect and almost always recur at the borders of the resection margin. There is no established chemotherapy regimen available to patients who recur, while systemic treatment is hampered by the blood-brain barrier. Here, we report on the first evaluation in humans of the intraparenchymal injection of irinotecan into the resection cavity after surgical resection of recurrent glioblastoma patients. The cytotoxicity of irinotecan was compared to SN-38 in primary cells from recurrent glioblastoma patients. Irinotecan was injected at multiple (~30) sites of the resection cavity wall at a depth of 3 to 5 mm. SN-38 was more cytotoxic than irinotecan at concentrations below 1 µM due to enzyme kinetics. The intraparenchymal administration of irinotecan was safe, with good wound healing and an absence of swelling, inflammation, or pseudo-abscess formation. The median survival post irinotecan administration was 32.6 weeks. The median overall survival was 30.5 months, with a two-year survival rate of 56%. This study demonstrates that local delivery of irinotecan into the brain parenchyma offers a safe route of administration over systemic delivery in the treatment of recurrent glioblastoma.

Chemodynamic Therapy of Glioblastoma Multiforme and Perspectives

Glioblastoma multiforme (GBM), a potential public health issue, is a huge challenge for the advanced scientific realm to solve. Chemodynamic therapy (CDT) based on the Fenton reaction emerged as a state-of-the-art therapeutic modality to treat GBM. However, crossing the blood-brain barrier (BBB) to reach the GBM is another endless marathon. In this review, the physiology of the BBB has been elaborated to understand the mechanism of crossing these potential barriers to treat GBM. Moreover, the designing of Fenton-based nanomaterials has been discussed for the production of reactive oxygen species in the tumor area to eradicate the cancer cells. For effective tumor targeting, biological nanomaterials that can cross the BBB via neurovascular transport channels have also been explored. To overcome the neurotoxicity caused by inorganic nanomaterials, the use of smart nanoagents having both enhanced biocompatibility and effective tumor targeting ability to enhance the efficiency of CDT are systematically summarized. Finally, the advancements in intelligent Fenton-based nanosystems for a multimodal therapeutic approach in addition to CDT are demonstrated. Hopefully, this systematic review will provide a better understanding of Fenton-based CDT and insight into GBM treatment.

The tumour microenvironment, treatment resistance and recurrence in glioblastoma

The adaptability of glioblastoma (GBM) cells, encouraged by complex interactions with the tumour microenvironment (TME), currently renders GBM an incurable cancer. Despite intensive research, with many clinical trials, GBM patients rely on standard treatments including surgery followed by radiation and chemotherapy, which have been observed to induce a more aggressive phenotype in recurrent tumours. This failure to improve treatments is undoubtedly a result of insufficient models which fail to incorporate components of the human brain TME. Research has increasingly uncovered mechanisms of tumour-TME interactions that correlate to worsened patient prognoses, including tumour-associated astrocyte mitochondrial transfer, neuronal circuit remodelling and immunosuppression. This tumour hijacked TME is highly implicated in driving therapy resistance, with further alterations within the TME and tumour resulting from therapy exposure inducing increased tumour growth and invasion. Recent developments improving organoid models, including aspects of the TME, are paving an exciting future for the research and drug development for GBM, with the hopes of improving patient survival growing closer. This review focuses on GBMs interactions with the TME and their effect on tumour pathology and treatment efficiency, with a look at challenges GBM models face in sufficiently recapitulating this complex and highly adaptive cancer.

Unmanageable Cerebrospinal Fluid Leakage With Eosinophilic Meningitis in a Gliadel Wafer Implant Patient

Gliadel wafer implants (Eisai Inc., Woodcliff Lake, NJ, USA) have shown their efficacy in prolonging survival in patients with malignant gliomas. The safety of Gliadel wafers has also been reported; however, there is a certain risk of adverse events. We present a rare case of refractory cerebrospinal fluid (CSF) leakage with eosinophilic meningitis in a patient with glioblastoma who underwent tumor resection with Gliadel wafer implants. A 60-year-old man presented with a glioblastoma in the right temporal lobe. The patient underwent tumor resection with Gliadel wafer implants. During the postoperative course, the patient presented with intractable CSF leakage and the development of a pseudomeningocele. A delayed rise in blood and CSF eosinophil count (a few weeks after the primary operation) and positive drug-induced lymphocyte stimulation test (DLST) results against the Gliadel wafer led to the diagnosis of an allergic reaction to these implants. Removal of the Gliadel wafers resolved the eosinophilic reaction; however, the patient subsequently required a shunt procedure for persistent hydrocephalus. This case highlights the importance of investigating rare causes of refractory CSF leakage and hydrocephalus due to allergic reactions to Gliadel wafers. Delayed elevations of eosinophils in blood and CSF tests may lead to a diagnosis of eosinophilic meningitis. DLST against Gliadel wafers is also useful for diagnosis when it is available. To control the hydrocephalus, not only the shunt procedure but also wafer removal must be considered; however, patients with limited life expectancy are generally hesitant to undergo such additional procedures.

Targeting brain tumors with innovative nanocarriers: bridging the gap through the blood-brain barrier

Background

Glioblastoma multiforme (GBM) is recognized as the most lethal and most highly invasive tumor. The high likelihood of treatment failure arises from the presence of the blood-brain barrier (BBB) and stem cells around GBM, which avert the entry of chemotherapeutic drugs into the tumor mass.

Objective

Recently, several researchers have designed novel nanocarrier systems like liposomes, dendrimers, metallic nanoparticles, nanodiamonds, and nanorobot approaches, allowing drugs to infiltrate the BBB more efficiently, opening up innovative avenues to prevail over therapy problems and radiation therapy.

Methods

Relevant literature for this manuscript has been collected from a comprehensive and systematic search of databases, for example, PubMed, Science Direct, Google Scholar, and others, using specific keyword combinations, including "glioblastoma," "brain tumor," "nanocarriers," and several others.

Conclusion

This review also provides deep insights into recent advancements in nanocarrier-based formulations and technologies for GBM management. Elucidation of various scientific advances in conjunction with encouraging findings concerning the future perspectives and challenges of nanocarriers for effective brain tumor management has also been discussed.

Engineered smart materials for RNA based molecular therapy to treat Glioblastoma

Glioblastoma (GBM) is an aggressive malignancy of the central nervous system (CNS) that remains incurable despite the multitude of improvements in cancer therapeutics. The conventional chemo and radiotherapy post-surgery have only been able to improve the prognosis slightly; however, the development of resistance and/or tumor recurrence is almost inevitable. There is a pressing need for adjuvant molecular therapies that can successfully and efficiently block tumor progression. During the last few decades, non-coding RNAs (ncRNAs) have emerged as key players in regulating various hallmarks of cancer including that of GBM. The levels of many ncRNAs are dysregulated in cancer, and ectopic modulation of their levels by delivering antagonists or overexpression constructs could serve as an attractive option for cancer therapy. The therapeutic potential of several types of ncRNAs, including miRNAs, lncRNAs, and circRNAs, has been validated in both in vitro and in vivo models of GBM. However, the delivery of these RNA-based therapeutics is highly challenging, especially to the tumors of the brain as the blood-brain barrier (BBB) poses as a major obstacle, among others. Also, since RNA is extremely fragile in nature, careful considerations must be met while designing a delivery agent. In this review we have shed light on how ncRNA therapy can overcome the limitations of its predecessor conventional therapy with an emphasis on smart nanomaterials that can aide in the safe and targeted delivery of nucleic acids to treat GBM. Additionally, critical gaps that currently exist for successful transition from viral to non-viral vector delivery systems have been identified. Finally, we have provided a perspective on the future directions, potential pathways, and target areas for achieving rapid clinical translation of, RNA-based macromolecular therapy to advance the effective treatment of GBM and other related diseases.

Development and validation of an LC-MS/MS method for the determination of ARN14988, an acid ceramidase inhibitor, and its application to a pharmacokinetic study in a mouse model

Despite aggressive treatment approaches, the overall survival of glioblastoma (GBM) patients remained poor with a strong need for more effective chemotherapeutic agents. A previous study has shown that ARN14988 is more cytotoxic to GBM cells compared to US Food and Drug Administration-approved temozolomide. This finding makes ARN14988 a desirable candidate for further pharmacological assessment. Therefore, an efficient analytical method is needed to quantify ARN14988. Herein, we have developed and validated sample preparation and LC-MS/MS triple quadrupole (QQQ) method for quantification of ARN14988 in mouse plasma. In this method, the liquid-liquid extraction of ARN14988 from mouse plasma was performed using 5% ethyl acetate in hexane. The chromatographic separation was achieved using a C18 -column with mobile phases of 10 mm ammonium acetate (pH 5) and 0.1% formic acid in methanol, within a runtime of 10 min. The monitored transitions were m/z 391.20 → m/z 147.00 for ARN14988, and m/z 455.30 → m/z 165.00 for verapamil (internal standard) in positive electrospray ionization. The developed method for ARN14988 showed linearity over the range of 10-5,000 ng/ml (r2  > 0.99). The selectivity, sensitivity, matrix effect, recovery, stability, inter-day and intraday accuracy and precision were determined using four quality control samples. This validated method was successfully applied to the pharmacokinetic study of ARN14988 in mice.

Anticancer drug delivery by focused ultrasound-mediated blood-brain/tumor barrier disruption for glioma therapy: From benchside to bedside

The therapeutic management of gliomas remains particularly challenging. Brain tumors present multiple obstacles that make therapeutic innovation complex, mainly due to the presence of blood-tumor and blood-brain barriers (BTB and BBB, respectively) which prevent penetration of anticancer agents into the brain parenchyma. Focused ultrasound-mediated BBB disruption (FUS-BBBD) provides a physical method for non-invasive, local, and reversible BBB disruption. The safety of this technique has been demonstrated in small and large animal models. This approach promises to enhance drug delivery into the brain tumor and therefore to improve survival outcomes by repurposing existing drugs. Several clinical trials continue to be initiated in the last decade. In this review, we provide an overview of the rationale behind the use of FUS-BBBD in gliomas and summarize the preclinical studies investigating different approaches (free drugs, drug-loaded microbubbles and drug-loaded nanocarriers) in combination with this technology in in vivo glioma models. Furthermore, we discuss the current state of clinical trials and devices developed and review the challenges to overcome for clinical use of FUS-BBBD in glioma therapy.

Soft Bioelectronics for Therapeutics

Soft bioelectronics play an increasingly crucial role in high-precision therapeutics due to their softness, biocompatibility, clinical accuracy, long-term stability, and patient-friendliness. In this review, we provide a comprehensive overview of the latest representative therapeutic applications of advanced soft bioelectronics, ranging from wearable therapeutics for skin wounds, diabetes, ophthalmic diseases, muscle disorders, and other diseases to implantable therapeutics against complex diseases, such as cardiac arrhythmias, cancer, neurological diseases, and others. We also highlight key challenges and opportunities for future clinical translation and commercialization of soft therapeutic bioelectronics toward personalized medicine.

Strategies increasing the effectiveness of temozolomide at various levels of anti-GBL therapy

Glioblastoma (GBL) is the most common (60-70% of primary brain tumours) and the most malignant of the glial tumours. Although current therapies remain palliative, they have been proven to prolong overall survival. Within an optimal treatment regimen (incl. surgical resection, radiation therapy, and chemotherapy) temozolomide as the current anti-GBL first-line chemotherapeutic has increased the median overall survival to 14-15 months, and the percentage of patients alive at two years has been reported to rise from 10.4% to 26.5%. Though, the effectiveness of temozolomide chemotherapy is limited by the serious systemic, dose-related side effects. Therefore, the ponderation regarding novel treatment methods along with innovative formulations is crucial to emerging the therapeutic potential of the widely used drug simultaneously reducing the drawbacks of its use. Herein the complex temozolomide application restrictions present at different levels of therapy as well as, the currently proposed strategies aimed at reducing those limitations are demonstrated. Approaches increasing the efficacy of anti-GBL treatment are addressed. Our paper is focused on the most recent developments in the field of nano/biomaterials-based systems for temozolomide delivery and their functionalization towards more effective blood-brain-barrier crossing and/or tumour targeting. Appropriate designing accounting for the physical and chemical features of formulations along with distinct routes of administration is also discussed. In addition, considering the multiple resistance mechanisms, the molecular heterogeneity and the evolution of tumour the purposely selected delivery methods, the combined therapeutic approaches and specifically focused on GBL cells therapies are reviewed.

Modulation of engineered nanomaterial interactions with organ barriers for enhanced drug transport

The biomedical use of nanoparticles (NPs) has been the focus of intense research for over a decade. As most NPs are explored as carriers to alter the biodistribution, pharmacokinetics and bioavailability of associated drugs, the delivery of these NPs to the tissues of interest remains an important topic. To date, the majority of NP delivery studies have used tumor models as their tool of interest, and the limitations concerning tumor targeting of systemically administered NPs have been well studied. In recent years, the focus has also shifted to other organs, each presenting their own unique delivery challenges to overcome. In this review, we discuss the recent advances in leveraging NPs to overcome four major biological barriers including the lung mucus, the gastrointestinal mucus, the placental barrier, and the blood-brain barrier. We define the specific properties of these biological barriers, discuss the challenges related to NP transport across them, and provide an overview of recent advances in the field. We discuss the strengths and shortcomings of different strategies to facilitate NP transport across the barriers and highlight some key findings that can stimulate further advances in this field.

Carmustine wafer implantation for supratentorial glioblastomas, IDH-wildtype in "extreme" neurosurgical conditions

We assessed the feasibility of Carmustine wafer implantation in "extreme" conditions (i.e. patients > 80 years and Karnofsky Performance Status score < 50) and of implantation ≥ 12 Carmustine wafers in adult patients harbouring a newly diagnosed supratentorial glioblastoma, IDH-wildtype. We performed an observational, retrospective single-centre cohort study at a tertiary surgical neuro-oncological centre between January 2006 and December 2021. Four hundred eighty patients who benefited from a surgical resection at first-line treatment were included. We showed that Carmustine wafer implantation in patients > 80 years, in patients with a Karnofsky performance status score < 50, and that implantation ≥ 12 Carmustine wafers (1) did not increase overall postoperative complication rates, (2) did not affect the completion of standard radiochemotherapy protocol, (3) did not worsen the postoperative Karnofsky Performance Status scores, and (4) did not significantly affect the time to oncological treatment. We showed that the implantation of ≥ 12 Carmustine wafers improved progression-free survival (31.0 versus 10.0 months, p = 0.025) and overall survival (39.0 versus 16.5 months, p = 0.041) without increasing postoperative complication rates. Carmustine wafer implantation during the surgical resection of a newly diagnosed supratentorial glioblastoma, IDH-wildtype is safe and efficient in patients > 80 years and in patients with preoperative Karnofsky Performance Status score < 50. The number of Carmustine wafers should be adapted (up to 16 in our experience) to the resection cavity to improve survival without increasing postoperative overall complication rates.

Personalized Treatment of Glioblastoma: Current State and Future Perspective

Glioblastoma (GBM) is the most aggressive glial tumor of the central nervous system. Despite intense scientific efforts, patients diagnosed with GBM and treated with the current standard of care have a median survival of only 15 months. Patients are initially treated by a neurosurgeon with the goal of maximal safe resection of the tumor. Obtaining tissue samples during surgery is indispensable for the diagnosis of GBM. Technological improvements, such as navigation systems and intraoperative monitoring, significantly advanced the possibility of safe gross tumor resection. Usually within six weeks after the surgery, concomitant radiotherapy and chemotherapy with temozolomide are initiated. However, current radiotherapy regimens are based on population-level studies and could also be improved. Implementing artificial intelligence in radiotherapy planning might be used to individualize treatment plans. Furthermore, detailed genetic and molecular markers of the tumor could provide patient-tailored immunochemotherapy. In this article, we review current standard of care and possibilities of personalizing these treatments. Additionally, we discuss novel individualized therapeutic options with encouraging results. Due to inherent heterogeneity of GBM, applying patient-tailored treatment could significantly prolong survival of these patients.

Self-assembling paclitaxel-mediated stimulation of tumor-associated macrophages for postoperative treatment of glioblastoma

The unique cancer-associated immunosuppression in brain, combined with a paucity of infiltrating T cells, contributes to the low response rate and poor treatment outcomes of T cell-based immunotherapy for patients diagnosed with glioblastoma multiforme (GBM). Here, we report on a self-assembling paclitaxel (PTX) filament (PF) hydrogel that stimulates macrophage-mediated immune response for local treatment of recurrent glioblastoma. Our results suggest that aqueous PF solutions containing aCD47 can be directly deposited into the tumor resection cavity, enabling seamless hydrogel filling of the cavity and long-term release of both therapeutics. The PTX PFs elicit an immune-stimulating tumor microenvironment (TME) and thus sensitizes tumor to the aCD47-mediated blockade of the antiphagocytic "don't eat me" signal, which subsequently promotes tumor cell phagocytosis by macrophages and also triggers an antitumor T cell response. As adjuvant therapy after surgery, this aCD47/PF supramolecular hydrogel effectively suppresses primary brain tumor recurrence and prolongs overall survivals with minimal off-target side effects.

Newly Diagnosed High-Grade Glioma Surgery with Carmustine Wafers Implantation. A Long-Term Nationwide Retrospective Study

BACKGROUND

Widespread use of carmustine wafers (CWs) to treat high-grade gliomas (HGG) has been limited by uncertainties about their efficacy. We sought to assess the outcome of patients after newly diagnosed HGG surgery with CW implantation and search for associated factors.

METHODS

We processed the French medico-administrative national database between 2008 and 2019 to retrieve ad hoc cases. Survival methods were implemented.

RESULTS

In total, 1608 patients who had CW implantation after HGG resection at 42 different institutions between 2008 and 2019 were identified; 36.7% were female and, median age at HGG resection with CW implantation was 61.5 years, interquartile range (IQR) [52.9-69.1]. A total of 1460 patients (90.8%) had died at data collection at a median age at death of 63.5 years, IQR [55.3-71.2]. Median overall survival (OS) was 1.42 years, 95% confidence interval [CI] 1.35-1.49, i.e., 16.8 months. Median age at death was 63.5 years, IQR [55.3-71.2]. OS at 1, 2, and, 5 years was 67.4%, 95% CI 65.1-69.7; 33.1%, 95% CI 30.9-35.5; and 10.7%, 95% CI 9.2-12.4, respectively. In the adjusted regression, sex (hazard ratio [HR] 0.82, 95% CI 0.74-0.92, P < 0.001), age at HGG surgery with CW implantation (HR 1.02, 95% CI 1.02-1.03, P < 0.001), adjuvant radiotherapy (HR 0.78, 95% CI 0.7-0.86, P < 0.001), chemotherapy by temozolomide (HR 0.7, 95% CI 0.63-0.79, P < 0.001), and redo surgery for HGG recurrence (HR 0.81, 95% CI 0.69-0.94, P = 0.005) remained significantly associated with the outcome.

CONCLUSIONS

OS of patients with newly diagnosed HGG who underwent surgery with CW implantation is better in young patients, those of the female sex, and for those who complete concomitant chemoradiotherapy. Redo surgery for HGG recurrence also was associated with prolonged survival.

Recurrent high grade glioma surgery with carmustine wafers implantation: a long-term nationwide retrospective study

PURPOSE

Widespread use of carmustine wafers (CW) to treat high-grade gliomas (HGG) has been limited by uncertainties about its efficacy. To assess the outcome of patients after recurrent HGG surgery with CW implantation and, search for associated factors.

METHODS

We processed the French medico-administrative national database between 2008 and 2019 to retrieve ad hoc cases. Survival methods were implemented.

RESULTS

559 patients who had CW implantation after recurrent HGG resection at 41 different institutions between 2008 and 2019 were identified. 35.6% were female and, median age at HGG resection with CW implantation was 58.1 years, IQR [50-65.4]. 520 patients (93%) had died at data collection with a median age at death of 59.7 years, IQR [51.6-67.1]. Median overall survival (OS) was 1.1 years, _95%CI[0.97-1.2], id est 13.2 months. Median age at death was 59.7 years, IQR [51.6-67.1]. OS at 1, 2 and 5 years was 52.1%, _95%CI[48.1-56.4], 24.6%, _95%CI[21.3-28.5] & 8%, _95%CI[5.9-10.7] respectively. In the adjusted regression, bevacizumab given before CW implantation, (HR = 1.98, _95%CI[1.49-2.63], p < 0.001), a longer delay between the first and the second HGG surgery (HR = 1, _95%CI[1-1], p < 0.001), RT given before and after CW implantation (HR = 0.59, _95%CI[0.39-0.87], p = 0.009) and TMZ given before and after CW implantation (HR = 0.81, _95%CI[0.66-0.98], p = 0.034) remained significantly associated with a longer survival.

CONCLUSION

OS of patients with recurrent HGG that underwent surgery with CW implantation is better in case of prolonged delay between the two resections and, for the patients who had RT and TMZ before and after CW implantation.

Highlighted Advances in Therapies for Difficult-To-Treat Brain Tumours Such as Glioblastoma

Glioblastoma multiforme (GBM) remains a challenging disease, as it is the most common and deadly brain tumour in adults and has no curative solution and an overall short survival time. This incurability and short survival time means that, despite its rarity (average incidence of 3.2 per 100,000 persons), there has been an increased effort to try to treat this disease. Standard of care in newly diagnosed glioblastoma is maximal tumour resection followed by initial concomitant radiotherapy and temozolomide (TMZ) and then further chemotherapy with TMZ. Imaging techniques are key not only to diagnose the extent of the affected tissue but also for surgery planning and even for intraoperative use. Eligible patients may combine TMZ with tumour treating fields (TTF) therapy, which delivers low-intensity and intermediate-frequency electric fields to arrest tumour growth. Nonetheless, the blood–brain barrier (BBB) and systemic side effects are obstacles to successful chemotherapy in GBM; thus, more targeted, custom therapies such as immunotherapy and nanotechnological drug delivery systems have been undergoing research with varying degrees of success. This review proposes an overview of the pathophysiology, possible treatments, and the most (not all) representative examples of the latest advancements.

Intracranial nanomedicine-gel with deep brain-penetration for glioblastoma therapy

Glioblastoma Multiforme (GBM) is one of the challenging tumors to treat as it recurs, almost 100%, even after surgery, radiation, and chemotherapy. In many cases, recurrence happens within 2-3cm depth of the resected tumor margin, indicating the inefficacy of current anti-glioma drugs to penetrate deep into the brain tissue. Here, we report an injectable nanoparticle-gel system, capable of providing deep brain penetration of drug up to 4 cm, releasing in a sustained manner up to >15 days. The system consists of ∼222 nm sized PLGA nanoparticles (NP-222) loaded with an anti-glioma drug, Carmustine (BCNU), and coated with a thick layer of polyethylene glycol (PEG). Upon release of the drug from PLGA core, it will interact with the outer PEG-layer leading to the formation of PEG-BCNU nanocomplexes of size ∼33 nm (BCNU-NC-33), which could penetrate >4 cm deep into the brain tissue compared to the free drug (< 5 mm). In vitro drug release showed sustained release of drug for 15 days by BCNU-NP gel, and enhanced cytotoxicity by BCNU-NC-33 drug-nanocomplexes in glioma cell lines. Ex vivo goat-brain phantom studies showed drug diffusion up to 4 cm in tissue and in vivo brain-diffusion studies showed almost complete coverage within the rat brain (∼1.2 cm), with ∼55% drug retained in the tissue by day-15, compared to only ∼5% for free BCNU. Rat orthotopic glioma studies showed excellent anti-tumor efficacy by BCNU-NP gel compared to free drug, indicating the potential of the gel-system for anti-glioma therapy. In effect, we demonstrate a unique method of sustained release of drug in the brain using larger PLGA nanoparticles acting as a reservoir while deep-penetration of the released drug was achieved by in situ formation of drug-nanocomplexes of size <50 nm which is less than the native pore size of brain tissue (> 100 nm). This method will have a major impact on a challenging field of brain drug delivery.

Intraoperative Ventricular Opening has No Effect on Complication Development Following BCNU Wafer Implantation for Malignant Glioma

OBJECTIVE

To evaluate the safety profile of bis-chloroethyl-nitrosourea (BCNU) wafer implantation after malignant glioma resection with or without ventricular opening (VO).

METHODS

This single-center retrospective study included 66 consecutive patients with BCNU wafer implantation after malignant glioma resection between March 2013 and August 2021. The patients were categorized into 2 groups based on whether VO occurred during the malignant glioma resection. Fifty-eight patients had glioblastoma, and 8 had anaplastic astrocytoma or oligodendroglioma. Forty-eight patients underwent an initial treatment, and 18 underwent recurrent surgeries. Infection, hydrocephalus, subcutaneous fluid collection, chronic subdural hematoma, early seizure after surgery within 1 month, symptomatic edema surrounding the resected cavity, cyst formation, and postoperative hemorrhage were defined as adverse events (AEs).

RESULTS

Thirty-three patients underwent resection with VO, and 33 without. The median survival time was 28 months in the initial treatment group and 11.5 months in the recurrent treatment group. The with and without VO groups had similar median survival times. Postoperative AEs occurred in 7/33 patients (21.2%) with VO and 10/33 (30.3%) without VO, with no difference between them (P = 0.574).

CONCLUSIONS

This study showed that VO during surgery with BCNU wafer implantation might not influence the occurrence of postoperative AEs. If VO happens, BCNU wafer implantation can be performed safely with accurate closing of the ventricle.

The clinical significance of radiological changes associated with gliadel implantation in patients with recurrent high grade glioma

Gliadel occasionally induces edema following its implantation. We aimed to correlate such post-surgical radiological changes to its efficacy and subsequent survival. Fifty-six patients with recurrent high grade glioma were treated between 2005 and 2016 with Gliadel implantation. Volumetric measurements of MRI features, including FLAIR abnormalities, tumor bulk (volume of gadolinium enhancement on T1) and resection cavity volumes over time were conducted. To assess dynamics over time, linear regression trendlines for each of these were calculated and examined to correlate with survival. Median follow-up after resection was 21.5 months. Median survival post-Gliadel implantation and overall survival since diagnosis were 12 months and 22 months, respectively. A subgroup of patients (n = 6) with a transient increase in FLAIR changes volume over time survived significantly longer post-Gliadel compared to those who did not demonstrate such change (36 vs 12 months, p = .03). Positive trends, representing overall growth in volume over time, of tumor bulk and resection cavity predicted survival in multivariate analyses (hazard ratios 7.9 and 84, p = .003 and .002, respectively). Increase in tumor bulk and resection cavity over time were associated with decreased survival, while transient FLAIR increase was a favorable prognostic factor. This may represent a transient inflammatory process in the tumor, possibly stemming from a presumed immune-mediated anti-tumor response.

Novel intraoperative strategies for enhancing tumor control: Future directions

Maximal safe surgical resection plays a key role in the care of patients with gliomas. A range of technologies have been developed to aid surgeons in distinguishing tumor from normal tissue, with the goal of increasing tumor resection and limiting postoperative neurological deficits. Technologies that are currently being investigated to aid in improving tumor control include intraoperative imaging modalities, fluorescent tumor makers, intraoperative cell and molecular profiling of tumors, improved microscopic imaging, intraoperative mapping, augmented and virtual reality, intraoperative drug and radiation delivery, and ablative technologies. In this review, we summarize the aforementioned advancements in neurosurgical oncology and implications for improving patient outcomes.

Advances in Preclinical/Clinical Glioblastoma Treatment: Can Nanoparticles Be of Help?

Glioblastoma multiforme (GB) is the most aggressive and frequent primary malignant tumor in the central nervous system (CNS), with unsatisfactory and challenging treatment nowadays. Current standard of care includes surgical resection followed by chemotherapy and radiotherapy. However, these treatments do not much improve the overall survival of GB patients, which is still below two years (the 5-year survival rate is below 7%). Despite various approaches having been followed to increase the release of anticancer drugs into the brain, few of them demonstrated a significant success, as the blood brain barrier (BBB) still restricts its uptake, thus limiting the therapeutic options. Therefore, enormous efforts are being devoted to the development of novel nanomedicines with the ability to cross the BBB and specifically target the cancer cells. In this context, the use of nanoparticles represents a promising non-invasive route, allowing to evade BBB and reducing systemic concentration of drugs and, hence, side effects. In this review, we revise with a critical view the different families of nanoparticles and approaches followed so far with this aim.

Brain targeted delivery of carmustine using chitosan coated nanoparticles via nasal route for glioblastoma treatment

This study aims to develop chitosan-coated PLGA nanoparticles intended for nose-to-brain delivery of carmustine. Formulations were prepared by the double emulsion solvent evaporation method and optimized by using Box-Behnken Design. The optimized nanoparticles were obtained to satisfactory levels in terms of particle size, PDI, entrapment efficiency, and drug loading. In vitro drug release and ex-vivo permeation showed sustained release and enhanced permeability (approx. 2 fold) of carmustine compared to drug suspension. The AUC_0-t of brain obtained with carmustine-loaded nanoparticles via nasal administration in Albino Wistar rats was 2.8 and 14.7 times that of intranasal carmustine suspension and intravenous carmustine, respectively. The MTT assay on U87 MG cell line showed a significant decrease (P < 0.05) in the IC50 value of the formulation (71.23 μg ml^-1) as compared to drug suspension (90.02 μg ml^-1).These findings suggest chitosan coated nanoparticles could be used to deliver carmustine via intranasal administration to treat Glioblastoma multiforme.

Novel rapid intraoperative qualitative tumor detection by a residual convolutional neural network using label-free stimulated Raman scattering microscopy

Determining the presence of tumor in biopsies and the decision-making during resections is often dependent on intraoperative rapid frozen-section histopathology. Recently, stimulated Raman scattering microscopy has been introduced to rapidly generate digital hematoxylin-and-eosin-stained-like images (stimulated Raman histology) for intraoperative analysis. To enable intraoperative prediction of tumor presence, we aimed to develop a new deep residual convolutional neural network in an automated pipeline and tested its validity. In a monocentric prospective clinical study with 94 patients undergoing biopsy, brain or spinal tumor resection, Stimulated Raman histology images of intraoperative tissue samples were obtained using a fiber-laser-based stimulated Raman scattering microscope. A residual network was established and trained in ResNetV50 to predict three classes for each image: (1) tumor, (2) non-tumor, and (3) low-quality. The residual network was validated on images obtained in three small random areas within the tissue samples and were blindly independently reviewed by a neuropathologist as ground truth. 402 images derived from 132 tissue samples were analyzed representing the entire spectrum of neurooncological surgery. The automated workflow took in a mean of 240 s per case, and the residual network correctly classified tumor (305/326), non-tumorous tissue (49/67), and low-quality (6/9) images with an inter-rater agreement of 89.6% (κ = 0.671). An excellent internal consistency was found among the random areas with 90.2% (Cα = 0.942) accuracy. In conclusion, the novel stimulated Raman histology-based residual network can reliably detect the microscopic presence of tumor and differentiate from non-tumorous brain tissue in resection and biopsy samples within 4 min and may pave a promising way for an alternative rapid intraoperative histopathological decision-making tool.

Efficient spatially targeted gene editing using a near-infrared activatable protein-conjugated nanoparticle for brain applications

Spatial control of gene expression is critical to modulate cellular functions and deconstruct the function of individual genes in biological processes. Light-responsive gene-editing formulations have been recently developed; however, they have shown limited applicability in vivo due to poor tissue penetration, limited cellular transfection and the difficulty in evaluating the activity of the edited cells. Here, we report a formulation composed of upconversion nanoparticles conjugated with Cre recombinase enzyme through a photocleavable linker, and a lysosomotropic agent that facilitates endolysosomal escape. This formulation allows in vitro spatial control in gene editing after activation with near-infrared light. We further demonstrate the potential of this formulation in vivo through three different paradigms: (i) gene editing in neurogenic niches, (ii) gene editing in the ventral tegmental area to facilitate monitoring of edited cells by precise optogenetic control of reward and reinforcement, and (iii) gene editing in a localized brain region via a noninvasive administration route (i.e., intranasal).

Spatial control of gene expression allows precise control over biological processes. Here, the authors develop an efficient light-responsive formulation based on upconversion nanoparticles, and demonstrate on-demand genetic manipulation in deep brain tissue.

Glioblastoma, from disease understanding towards optimal cell-based in vitro models

Background

Glioblastoma (GBM) patients are notoriously difficult to treat and ultimately all succumb to disease. This unfortunate scenario motivates research into better characterizing and understanding this disease, and into developing novel research tools by which potential novel therapeutics and treatment options initially can be evaluated pre-clinically. Here, we provide a concise overview of glioblastoma epidemiology, disease classification, the challenges faced in the treatment of glioblastoma and current novel treatment strategies. From this, we lead into a description and assessment of advanced cell-based models that aim to narrow the gap between pre-clinical and clinical studies. Such invitro models are required to deliver reliable and meaningful data for the development and pre-validation of novel therapeutics and treatments.

Conclusions

The toolbox for GBM cell-based models has expanded substantially, with the possibility of 3D printing tumour tissues and thereby replicating invivo tissue architectures now looming on the horizon. A comparison of experimental cell-based model systems and techniques highlights advantages and drawbacks of the various tools available, based on which cell-based models and experimental approaches best suited to address a diversity of research questions in the glioblastoma research field can be selected.

Blood-brain barrier: emerging trends on transport models and new-age strategies for therapeutics intervention against neurological disorders

The integrity of the blood–brain barrier (BBB) is essential for normal central nervous system (CNS) functioning. Considering the significance of BBB in maintaining homeostasis and the neural environment, we aim to provide an overview of significant aspects of BBB. Worldwide, the treatment of neurological diseases caused by BBB disruption has been a major challenge. BBB also restricts entry of neuro-therapeutic drugs and hinders treatment modalities. Hence, currently nanotechnology-based approaches are being explored on large scale as alternatives to conventional methodologies. It is necessary to investigate the in-depth characteristic features of BBB to facilitate the discovery of novel drugs that can successfully cross the barrier and target the disease effectively. It is imperative to discover novel strategies to treat life-threatening CNS diseases in humans. Therefore, insights regarding building blocks of BBB, activation of immune response on breach of this barrier, and various autoimmune neurological disorders caused due to BBB dysfunction are discussed. Further, special emphasis is given on delineating BBB disruption leading to CNS disorders. Moreover, various mechanisms of transport pathways across BBB, several novel strategies, and alternative routes by which drugs can be properly delivered into CNS are also discussed.

Targeting the Axl and mTOR Pathway Synergizes Immunotherapy and Chemotherapy to Butylidenephthalide in a Recurrent GBM

Background. The role of inherent tumor heterogeneity and an immunosuppressive microenvironment in therapeutic resistance has been determined to be of importance for the better management of glioblastoma multiforme (GBM). Some studies have suggested that combined drugs with divergent mechanisms may be promising in treating recurrent GBM. Methods. Intracranial sustained (Z)-n-butylidenephthalide [(Z)-BP] delivery through Cerebraca Wafers (CWs) to eliminate unresectable brain tumors was combined with the administration of temozolomide (TMZ), pembrolizumab, and cytokine-induced killer (CIK) cells for treating a patient with recurrent glioblastoma. Neurological adverse events and wound healing delay were monitored for estimating tolerance and efficacy. Response Assessment in Neuro-Oncology criteria were applied to evaluate progression-free survival (PFS); further, the molecular characteristics of GBM tissues were analyzed, and the underlying mechanism was investigated using primary culture. Results. Intracerebral (Z)-BP in residual tumors could not only inhibit cancer stem cells but also increase interferon gamma levels in serum, which then led to the regression of GBM and an immune-responsive microenvironment. Targeting receptor tyrosine kinases, including Axl and epidermal growth factor receptor (EGFR), and inhibiting the mechanistic target of rapamycin (mTOR) through (Z)-BP were determined to synergize CIK cells in the presence of pembrolizumab and TMZ in recurrent GBM. Therefore, this well-tolerated regimen could simultaneously block multiple cancer pathways, which allowed extended PFS and improved quality of life for 22 months. Conclusion. Given the several unique functions of (Z)-BP, greater sensitivity of chemotherapy and the synergism of pembrolizumab and CIK cells could have affected the excellent prognosis seen in this patient with recurrent GBM.

Design of Biopolymer-Based Interstitial Therapies for the Treatment of Glioblastoma

Glioblastoma multiforme (GBM) is the most common form of primary brain cancer and has the highest morbidity rate and current treatments result in a bleak 5-year survival rate of 5.6%. Interstitial therapy is one option to increase survival. Drug delivery by interstitial therapy most commonly makes use of a polymer implant encapsulating a drug which releases as the polymer degrades. Interstitial therapy has been extensively studied as a treatment option for GBM as it provides several advantages over systemic administration of chemotherapeutics. Primarily, it can be applied behind the blood–brain barrier, increasing the number of possible chemotherapeutic candidates that can be used and reducing systemic levels of the therapy while concentrating it near the cancer source. With interstitial therapy, multiple drugs can be released locally into the brain at the site of resection as the polymer of the implant degrades, and the release profile of these drugs can be tailored to optimize combination therapy or maintain synergistic ratios. This can bypass the blood–brain barrier, alleviate systemic toxicity, and resolve drug resistance in the tumor. However, tailoring drug release requires appropriate consideration of the complex relationship between the drug, polymer, and formulation method. Drug physicochemical properties can result in intermolecular bonding with the polymeric matrix and affect drug distribution in the implant depending on the formulation method used. This review is focused on current works that have applied interstitial therapy towards GBM, discusses polymer and formulation methods, and provides design considerations for future implantable biodegradable materials.

Antibody Drug Conjugates in Glioblastoma - Is There a Future for Them?

Glioblastoma (GBM) is an aggressive and fatal malignancy that despite decades of trials has limited therapeutic options. Antibody drug conjugates (ADCs) are composed of a monoclonal antibody which specifically recognizes a cellular surface antigen linked to a cytotoxic payload. ADCs have demonstrated superior efficacy and/or reduced toxicity in a range of haematological and solid tumors resulting in nine ADCs receiving regulatory approval. ADCs have also been explored in patients with brain tumours but with limited success to date. While earlier generations ADCs in glioma patients have had limited success and high toxicity, newer and improved ADCs characterised by low immunogenicity and more effective payloads have shown promise in a range of tumour types. These newer ADCs have also been tested in glioma patients, however, with mixed results. Factors affecting the effectiveness of ADCs to target the CNS include the blood brain barrier which acts as a physical and biochemical barrier, the pro-cancerogenic and immunosuppressive tumor microenvironment and tumour characteristics like tumour volume and antigen expression. In this paper we review the data regarding the ongoing the development of ADCs in glioma patients as well as potential strategies to overcome these barriers to maximise their therapeutic potential.

Rationally designed drug delivery systems for the local treatment of resected glioblastoma

Glioblastoma (GBM) is a particularly aggressive brain cancer associated with high recurrence and poor prognosis. The standard of care, surgical resection followed by concomitant radio- and chemotherapy, leads to low survival rates. The local delivery of active agents within the tumor resection cavity has emerged as an attractive means to initiate oncological treatment immediately post-surgery. This complementary approach bypasses the blood-brain barrier, increases the local concentration at the tumor site while reducing or avoiding systemic side effects. This review will provide a global overview on the local treatment for GBM with an emphasis on the lessons learned from past clinical trials. The main parameters to be considered to rationally design fit-of-purpose biomaterials and develop drug delivery systems for local administration in the GBM resection cavity to prevent the tumor recurrence will be described. The intracavitary local treatment of GBM should i) use materials that facilitate translation to the clinic; ii) be characterized by easy GMP effective scaling up and easy-handling application by the neurosurgeons; iii) be adaptable to fill the tumor-resected niche, mold to the resection cavity or adhere to the exposed brain parenchyma; iv) be biocompatible and possess mechanical properties compatible with the brain; v) deliver a therapeutic dose of rationally-designed or repurposed drug compound(s) into the GBM infiltrative margin. Proof of concept with high translational potential will be provided. Finally, future perspectives to facilitate the clinical translation of the local perisurgical treatment of GBM will be discussed.

Polymeric Composite Matrix with High Biobased Content as Pharmaceutically Relevant Molecular Encapsulation and Release Platform

Drug delivery systems (DDS) that can temporally control the rate and extent of release of therapeutically active molecules find applications in many clinical settings, ranging from infection control to cancer therapy. With an aim to design a locally implantable, controlled-release DDS, we demonstrated the feasibility of using cellulose nanocrystal (CNC)-reinforced poly (l-lactic acid) (PLA) composite beads. The performance of the platform was evaluated using doxorubicin (DOX) as a model drug for applications in triple-negative breast cancer. A facile, nonsolvent-induced phase separation (NIPS) method was adopted to form composite beads. We observed that CNC loading within these beads played a critical role in the mechanical stability, porosity, water uptake, diffusion, release, and pharmacological activity of the drug from the delivery system. When loaded with DOX, composite beads significantly controlled the release of the drug in a pH-dependent pattern. For example, PLA/CNC beads containing 37.5 wt % of CNCs showed a biphasic release of DOX, where 41 and 82% of the loaded drug were released at pH 7.4 and pH 5.5, respectively, over 7 days. Drug release followed Korsmeyer's kinetics, indicating that the release mechanism was mostly diffusion and swelling-controlled. We showed that DOX released from drug-loaded PLA/CNC composite beads locally suppressed the growth and proliferation of triple-negative breast cancer cells, MBA-MB-231, via the apoptotic pathway. The efficacy of the DDS was evaluated in human tissue explants. We envision that such systems will find applications for designing biobased platforms with programmed stability and drug delivery functions.

Emerging Nano-Carrier Strategies for Brain Tumor Drug Delivery and Considerations for Clinical Translation

Treatment of brain tumors is challenging since the blood–brain tumor barrier prevents chemotherapy drugs from reaching the tumor site in sufficient concentrations. Nanomedicines have great potential for therapy of brain disorders but are still uncommon in clinical use despite decades of research and development. Here, we provide an update on nano-carrier strategies for improving brain drug delivery for treatment of brain tumors, focusing on liposomes, extracellular vesicles and biomimetic strategies as the most clinically feasible strategies. Finally, we describe the obstacles in translation of these technologies including pre-clinical models, analytical methods and regulatory issues.

G-protein-coupled receptors as therapeutic targets for glioblastoma

Glioblastoma multiforme (GBM) is the most common and aggressive primary brain tumour in adults. Treatments include surgical resection, radiotherapy, and chemotherapy. Despite this, the prognosis remains poor, with an impacted quality of life during treatment coupled with brain tumour recurrence; thus, new treatments are desperately needed. In this review, we focus on recent advances in G-protein-coupled receptor (GPCR) targets. To date, the most promising targets are the chemokine, cannabinoid, and dopamine receptors, but future work should further examine the melanocortin receptor-4 (MC4R), adhesion, lysophosphatidic acid (LPA) and smoothened (Smo) receptors to initiate new drug-screening strategies and targeted delivery of safe and effective GBM therapies.

The drug development pipeline for glioblastoma-A cross sectional assessment of the FDA Orphan Drug Product designation database

BACKGROUND

Glioblastoma (GBM) is the most common malignant brain tumour among adult patients and represents an almost universally fatal disease. Novel therapies for GBM are being developed under the orphan drug legislation and the knowledge on the molecular makeup of this disease has been increasing rapidly. However, the clinical outcomes in GBM patients with currently available therapies are still dismal. An insight into the current drug development pipeline for GBM is therefore of particular interest.

OBJECTIVES

To provide a quantitative clinical-regulatory insight into the status of FDA orphan drug designations for compounds intended to treat GBM.

METHODS

Quantitative cross-sectional analysis of the U.S. Food and Drug Administration Orphan Drug Product database between 1983 and 2020. STROBE criteria were respected.

RESULTS

Four orphan drugs out of 161 (2,4%) orphan drug designations were approved for the treatment for GBM by the FDA between 1983 and 2020. Fourteen orphan drug designations were subsequently withdrawn for unknown reasons. The number of orphan drug designations per year shows a growing trend. In the last decade, the therapeutic mechanism of action of designated compounds intended to treat glioblastoma shifted from cytotoxic drugs (median year of designation 2008) to immunotherapeutic approaches and small molecules (median year of designation 2014 and 2015 respectively) suggesting an increased focus on precision in the therapeutic mechanism of action for compounds the development pipeline.

CONCLUSION

Despite the fact that current pharmacological treatment options in GBM are sparse, the drug development pipeline is steadily growing. In particular, the surge of designated immunotherapies detected in the last years raises the hope that elaborate combination possibilities between classical therapeutic backbones (radiotherapy and chemotherapy) and novel, currently experimental therapeutics may help to provide better therapies for this deadly disease in the future.

Marizomib sensitizes primary glioma cells to apoptosis induced by a latest-generation TRAIL receptor agonist

Due to the absence of curative treatments for glioblastoma (GBM), we assessed the efficacy of single and combination treatments with a translationally relevant 2nd generation TRAIL-receptor agonist (IZI1551) and the blood–brain barrier (BBB) permeant proteasome inhibitor marizomib in a panel of patient-derived glioblastoma cell lines. These cells were cultured using protocols that maintain the characteristics of primary tumor cells. IZI1551+marizomib combination treatments synergistically induced apoptotic cell death in the majority of cases, both in 2D, as well as in 3D spheroid cultures. In contrast, single-drug treatments largely failed to induce noticeable amounts of cell death. Kinetic analyses suggested that time-shifted drug exposure might further increase responsiveness, with marizomib pre-treatments indeed strongly enhancing cell death. Cell death responses upon the addition of IZI1551 could also be observed in GBM cells that were kept in a medium collected from the basolateral side of a human hCMEC/D3 BBB model that had been exposed to marizomib. Interestingly, the subset of GBM cell lines resistant to IZI1551+marizomib treatments expressed lower surface amounts of TRAIL death receptors, substantially lower amounts of procaspase-8, and increased amounts of cFLIP, suggesting that apoptosis initiation was likely too weak to initiate downstream apoptosis execution. Indeed, experiments in which the mitochondrial apoptosis threshold was lowered by antagonizing Mcl-1 re-established sensitivity to IZI1551+marizomib in otherwise resistant cells. Overall, our study demonstrates a high efficacy of combination treatments with a latest-generation TRAIL receptor agonist and the BBB permeant proteasome inhibitor marizomib in relevant GBM cell models, as well as strategies to further enhance responsiveness and to sensitize subgroups of otherwise resistant GBM cases.

Captopril inhibits Matrix Metalloproteinase-2 and extends survival as a temozolomide adjuvant in an intracranial gliosarcoma model

BACKGROUND

Captopril is a well-characterized, FDA-approved drug that has demonstrated promise as a repurposed oncology therapeutic. Captopril's known anti-cancer effects include inhibition of Matrix Metalloproteinase-2 (MMP-2), an endopeptidase which selectively breaks down the extracellular matrix to promote cell migration. MMP-2 is a known therapeutic target in gliomas, tumors with significant clinical need. Using an aggressive gliosarcoma model, we assessed captopril's effects on MMP-2 expression in vitro and in vivo as well as its efficacy as an adjuvant in combination therapy regimens in vivo.

METHODS

Following captopril treatment, MMP-2 protein expression and migratory capabilities of 9 L gliosarcoma cells were assessed in vitro via western blots and scratch wound assays, respectively. Rats were intracranially implanted with 9 L gliosarcoma tumors, and survival was assessed in the following groups: control; captopril (30 mg/kg/day); temozolomide (TMZ) (50 mg/kg/day), and captopril+TMZ. In vivo experiments were accompanied by immunohistochemistry for MMP-2 from brain tissue.

RESULTS

In vitro, captopril decreased MMP-2 protein expression and reduced migratory capacity in 9 L gliosarcoma cells. In a gliosarcoma animal model, captopril decreased MMP-2 protein expression and extended survival as a TMZ adjuvant relative to untreated controls, captopril monotherapy, and TMZ monotherapy groups (27.5 versus 14 (p < 0.001), 16 (p < 0.001), and 23 (p = 0.018) days, respectively).

CONCLUSIONS

Captopril decreases gliosarcoma cell migration, which may be mediated by reduction in MMP-2 protein expression. Captopril provided a survival advantage as a TMZ adjuvant in a rat intracranial gliosarcoma model. Captopril may represent a promising potential adjuvant to TMZ therapy in gliosarcoma as a modulator of the MMP-2 pathway.

Drug penetration in pediatric brain tumors: Challenges and opportunities

Larger clinical trial enrollments and a greater understanding of biological heterogeneity have led to improved survival rates for children diagnosed with brain tumors in the last 50 years. However, reducing long-term morbidities and improving survival rates of high-risk tumors remain major challenges. Chemotherapy can reduce tumor burden, but effective drug penetration at the tumor site is limited by barriers in the route of drug administration and within the tumor microenvironment. Bioavailability of drugs is impeded by the blood-brain barrier, plasma protein binding, and structural components by the tumor including the matrix and vasculature contributing to increased interstitial fluid pressure, hypoxia, and acidity. Designing drug delivery systems to circumvent these barriers could lead to improved drug penetration at the tumor site and reduce adverse systemic side effects. In this review, we expand on how systemic and local barriers limit drug penetration and present potential methods to enhance drug penetration in pediatric brain tumors.