Blood-Brain Barrier Permeability Following Conventional Photon Radiotherapy - A Systematic Review and Meta-Analysis of Clinical and Preclinical Studies

Triple therapy boosts survival in NSCLC patients with brain metastases: a retrospective cohort study of chemotherapy, ICIs, and antiangiogenic agents

BACKGROUND

Treatment of brain metastases (BMs) in non-small cell lung cancer (NSCLC) patients, especially those with non-sensitive genetic mutations, is hindered by limited drug delivery through the blood-brain barrier (BBB). This retrospective study explores the efficacy of systemic treatments during brain metastasis to radiotherapy evaluation window in improving patient survival.

METHODS

In this retrospective cohort study, we evaluated 209 NSCLC patients with non-sensitive mutations and BMs, treated between 2016 and 2023 at two tertiary medical centers (Chongqing University Cancer Hospital and Guangxi Medical University Cancer Hospital). The patients were divided into three groups, namely chemotherapy alone (C; n = 95), chemotherapy plus immune checkpoint inhibitors (ICIs) (C + I; n = 62), and chemotherapy with ICIs and antiangiogenic therapy (A) (C + I + A; n = 52). Statistical analyses were performed using R software, version 4.3.3. Categorical variables were compared using Fisher's exact test, and survival curves were estimated with the Kaplan-Meier method and compared via the log-rank test. Univariate and multivariate Cox regression models were used to assess factors associated with overall survival (OS). Bayesian model averaging (BMA) was employed to address model uncertainty and improve result robustness. Subgroup analyses evaluated treatment-related mortality risk.

RESULTS

From an initial cohort of 658 NSCLC patients with BMs, 209 were analyzed with a median age of 59; the majority were male (80.9%) and diagnosed with adenocarcinoma (78.9%). Univariate analysis identified significant variables influencing outcomes, including BMs radiotherapy EQD2, BMs count, local thoracic treatment, BMs radiotherapy field, intracranial response, and systemic treatment post-BMs diagnosis. The C + I + A regimen significantly improved median OS to 23.6 months compared to 11.4 months with C and 16.2 months with C + I, with a hazard ratio (HR) of 0.60 (95% CI: 0.43-0.82; P < 0.0001). The two-year OS rate was highest in the C + I + A group at 38.5%, versus 10.5% in C and 20.4% in C + I (P < 0.001). Cox regression and BMA analyses confirmed the stability of BMA in providing HR estimates, yielding area under the curve (AUC) values of 0.785 for BMA and 0.793 for the Cox model, with no significant difference in predictive performance. Subgroup analysis revealed a 71% mortality risk reduction with C + I + A (HR: 0.29; 95% CI: 0.18-0.47; P < 0.0001), showing consistent benefits regardless of patient sex, BMs count, extracranial metastases presence, and local thoracic treatments. Treatment sequence analysis indicated a median OS of 33.4 months for patients starting with A, though not statistically significant (HR: 0.59; P = 0.36). The overall incidence of radiation-induced brain injury was low at 3.3%, with rates in the C, C + I, and C + I + A groups being 3.2%, 4.8%, and 1.9%, respectively (P = 0.683).

CONCLUSION

Our study demonstrates the significant benefit of the C + I + A combination therapy in improving OS and reducing mortality risk in NSCLC patients with non-sensitive gene-mutated BMs. The sequential administration of A followed by ICIs shows a promising synergistic effect with cranial radiotherapy, highlighting the potential for optimized treatment sequencing. These findings emphasize the efficacy of tailored combination therapies in complex oncological care and suggest that our approach could lead to meaningful improvements in clinical outcomes for this challenging patient population.

Case report of two long term ovarian cancer survivors with brain metastases following multimodal treatment including chemotherapy, radiotherapy and maintenance olaparib: An institutional case series and literature review

Brain metastasis from ovarian cancer is a very rare condition with a poor prognosis. However, due to its rarity, there is no established treatment strategy. We present a case series of brain metastasis with ovarian cancer, focusing on two long-term survivors treated with multimodal therapy. Among the nine cases, the median survival time after brain metastases was six months (range: 0-58 months). Eight patients had high-grade serous carcinoma (HGSC). Three of the four patients who underwent genetic testing tested positive for germline BRCA2 (gBRCA2) mutation. Two patients survived longer than 4 years after the diagnosis of brain metastases. Both of these patients received chemotherapy, radiation therapy, and olaparib, a molecularly targeted drug, as maintenance therapy. This case series suggests that patients with gBRCA2 mutation-positive HGSC may be at a high risk of developing brain metastases. A multidisciplinary approach, including PARP inhibitors, may improve the prognosis of patients with brain metastases from ovarian cancer.

Deformation-based morphometry: a sensitive imaging approach to detect radiation-induced brain injury?

BACKGROUND

Radiotherapy is a major therapeutic approach in patients with brain tumors. However, it leads to cognitive impairments. To improve the management of radiation-induced brain sequalae, deformation-based morphometry (DBM) could be relevant. Here, we analyzed the significance of DBM using Jacobian determinants (JD) obtained by non-linear registration of MRI images to detect local vulnerability of healthy cerebral tissue in an animal model of brain irradiation.

METHODS

Rats were exposed to fractionated whole-brain irradiation (WBI, 30 Gy). A multiparametric MRI (anatomical, diffusion and vascular) study was conducted longitudinally from 1 month up to 6 months after WBI. From the registration of MRI images, macroscopic changes were analyzed by DBM and microscopic changes at the cellular and vascular levels were evaluated by quantification of cerebral blood volume (CBV) and diffusion metrics including mean diffusivity (MD). Voxel-wise comparisons were performed on the entire brain and in specific brain areas identified by DBM. Immunohistology analyses were undertaken to visualize the vessels and astrocytes.

RESULTS

DBM analysis evidenced time-course of local macrostructural changes; some of which were transient and some were long lasting after WBI. DBM revealed two vulnerable brain areas, namely the corpus callosum and the cortex. DBM changes were spatially associated to microstructural alterations as revealed by both diffusion metrics and CBV changes, and confirmed by immunohistology analyses. Finally, matrix correlations demonstrated correlations between JD/MD in the early phase after WBI and JD/CBV in the late phase both in the corpus callosum and the cortex.

CONCLUSIONS

Brain irradiation induces local macrostructural changes detected by DBM which could be relevant to identify brain structures prone to radiation-induced tissue changes. The translation of these data in patients could represent an added value in imaging studies on brain radiotoxicity.

Blood-Brain Barrier Disruption for the Treatment of Primary Brain Tumors: Advances in the Past Half-Decade

PURPOSE OF REVIEW

To review relevant advances in the past half-decade in the treatment of primary brain tumors via modification of blood-brain barrier (BBB) permeability.

RECENT FINDINGS

BBB disruption is becoming increasingly common in the treatment of primary brain tumors. Use of mannitol in BBB disruption for targeted delivery of chemotherapeutics via superselective intra-arterial cerebral infusion (SIACI) is the most utilized strategy to modify the BBB. Mannitol is used in conjunction with chemotherapeutics, oligonucleotides, and other active agents. Convection-enhanced delivery has become an attractive option for therapeutic delivery while bypassing the BBB. Other technologic innovations include laser interstitial thermal therapy (LITT) and focused ultrasound (FUS) which have emerged as prime modalities to directly target tumors and cause significant local BBB disruption. In the past 5 years, interest has significantly increased in studying modalities to disrupt the BBB in primary brain tumors to enhance treatment responses and improve clinical outcomes.

Inhibition of epigenetic and cell cycle-related targets in glioblastoma cell lines reveals that onametostat reduces proliferation and viability in both normoxic and hypoxic conditions

The choice of targeted therapies for treatment of glioblastoma patients is currently limited, and most glioblastoma patients die from the disease recurrence. Thus, systematic studies in simplified model systems are required to pinpoint the choice of targets for further exploration in clinical settings. Here, we report screening of 5 compounds targeting epigenetic writers or erasers and 6 compounds targeting cell cycle-regulating protein kinases against 3 glioblastoma cell lines following incubation under normoxic or hypoxic conditions. The viability/proliferation assay indicated that PRMT5 inhibitor onametostat was endowed with high potency under both normoxic and hypoxic conditions in cell lines that are strongly MGMT-positive (T98-G), weakly MGMT-positive (U-251 MG), or MGMT-negative (U-87 MG). In U-251 MG and U-87 MG cells, onametostat also affected the spheroid formation at concentrations lower than the currently used chemotherapeutic drug lomustine. In T98-G cell line, treatment with onametostat led to dramatic changes in the transcriptome profile by inducing the cell cycle arrest, suppressing RNA splicing, and down-regulating several major glioblastoma cell survival pathways. Further validation by immunostaining in three cell lines confirmed that onametostat affects cell cycle and causes reduction in nucleolar protein levels. In this way, inhibition of epigenetic targets might represent a viable strategy for glioblastoma treatment even in the case of decreased chemo- and radiation sensitivity, although further studies in clinically more relevant models are required.

Synergistically Enhancing Immunotherapy Efficacy in Glioblastoma with Gold-Core Silica-Shell Nanoparticles and Radiation

Purpose

Glioblastoma is a highly aggressive brain tumor with universally poor outcomes. Recent progress in immune checkpoint inhibitors has led to increased interest in their application in glioblastoma. Nonetheless, the unique immune milieu in the brain has posed remarkable challenges to the efficacy of immunotherapy. We aimed to leverage the radiation-induced immunogenic cell death to overcome the immunosuppressive network in glioblastoma.

Methods

We developed a novel approach using the gold-core silica-shell nanoparticles (Au@SiO2 NPs) in combination with low-dose radiation to enhance the therapeutic efficacy of the immune checkpoint inhibitor (atezolizumab) in brain tumors. The biocompatibility, immune cell recruitment, and antitumor ability of the combinatorial strategy were determined using in vitro assays and in vivo models.

Results

Our approach successfully induced the migration of macrophages towards brain tumors and promoted cancer cell apoptosis. Subcutaneous tumor models demonstrated favorable safety profiles and significantly enhanced anticancer effects. In orthotopic brain tumor models, the multimodal therapy yielded substantial prognostic benefits over any individual modalities, achieving an impressive 40% survival rate.

Conclusion

In summary, the combination of Au@SiO2 NPs and low-dose radiation holds the potential to improve the clinical efficacy of immune checkpoint inhibitors. The synergetic strategy modulates tumor microenvironments and enhances systemic antitumor immunity, paving a novel way for glioblastoma treatment.

Pertuzumab plus high-dose trastuzumab for HER2-positive breast cancer with brain metastases: PATRICIA final efficacy data

The PATRICIA study (NCT02536339) examined the efficacy and safety of pertuzumab plus high-dose trastuzumab in patients with HER2-positive metastatic breast cancer (MBC) with progressive central nervous system (CNS) metastases following radiotherapy. Primary analysis confirmed CNS objective response rate (ORR) was 11% (95% confidence interval [CI]: 3-25); clinical benefit rate (CBR) was 68% (4 months) and 51% (6 months). We report final efficacy data after a further 21-months of follow-up, updated safety, survival, and patient-reported outcomes (PROs). Patients received standard-dose pertuzumab plus high-dose trastuzumab (6 mg/kg weekly) until CNS or systemic disease progression or unacceptable toxicity. Primary endpoint: confirmed ORR (CNS) per Response Assessment in Neuro-Oncology Brain Metastases criteria. Secondary endpoints were response duration, CBR, progression-free survival (PFS), overall survival (OS), safety, and PROs. By clinical cut-off, 39 patients had completed or discontinued treatment. Confirmed ORR (CNS) was 11% (95% CI: 3.0-25.4). Median CNS-PFS was 4.6 months (95% CI: 4.0-8.9), as was median CNS-PFS or systemic PFS (95% CI: 4.0-8.9); median OS was 27.2 months (95% CI: 16.1-not reached). CBR in the CNS was 51% (19 patients, 95% CI: 34.4-68.1) at 6 months. Two patients remained on treatment until study closure, achieving stable disease for 4.1 and 4.8 years. Treatment-related grade 3/4 adverse events occurred in 7.7% of patients. Patients with confirmed partial response or stable disease (≥4 months) in the CNS had stable PROs over time. Pertuzumab plus high-dose trastuzumab represents a reasonable non-chemotherapeutic treatment option for selected patients with HER2-positive MBC with CNS metastases.

Non-cellular immunotherapies in pediatric central nervous system tumors

Central nervous system (CNS) tumors are the second most common type of cancer and the most common cause of cancer death in pediatric patients. New therapies are desperately needed for some of the most malignant of all cancers. Immunotherapy has emerged in the past two decades as an additional avenue to augment/replace traditional therapies (such as chemotherapy, surgery, and radiation therapy). This article first discusses the unique nature of the pediatric CNS immune system and how it interacts with the systemic immune system. It then goes on to review three important and widely studied types of immune therapies: checkpoint inhibitors, vaccines, and radiation therapy, and touches on early studies of antibody-mediated immunogenic therapies, Finally, the article discusses the importance of combination immunotherapy for pediatric CNS tumors, and addresses the neurologic toxicities associated with immunotherapies.

Blood-brain-barrier modeling with tissue chips for research applications in space and on Earth

Tissue chip technology has revolutionized biomedical applications and the medical science field for the past few decades. Currently, tissue chips are one of the most powerful research tools aiding in in vitro work to accurately predict the outcome of studies when compared to monolayer two-dimensional (2D) cell cultures. While 2D cell cultures held prominence for a long time, their lack of biomimicry has resulted in a transition to 3D cell cultures, including tissue chips technology, to overcome the discrepancies often seen in in vitro studies. Due to their wide range of applications, different organ systems have been studied over the years, one of which is the blood brain barrier (BBB) which is discussed in this review. The BBB is an incredible protective unit of the body, keeping out pathogens from entering the brain through vasculature. However, there are some microbes and certain diseases that disrupt the function of this barrier which can lead to detrimental outcomes. Over the past few years, various designs of the BBB have been proposed and modeled to study drug delivery and disease modeling on Earth. More recently, researchers have started to utilize tissue chips in space to study the effects of microgravity on human health. BBB tissue chips in space can be a tool to understand function mechanisms and therapeutics. This review addresses the limitations of monolayer cell culture which could be overcome with utilizing tissue chips technology. Current BBB models on Earth and how they are fabricated as well as what influences the BBB cell culture in tissue chips are discussed. Then, this article reviews how application of these technologies together with incorporating biosensors in space would be beneficial to help in predicting a more accurate physiological response in specific tissue or organ chips. Finally, the current platforms used in space and some solutions to overcome some shortcomings for future BBB tissue chip research are also discussed.

Experimental study of EGFR-TKI aumolertinib combined with ionizing radiation in EGFR mutated NSCLC brain metastases tumor

Aumolertinib is an irreversible third-generation epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI), although it has been administered for the treatment of epidermal growth factor receptor (EGFR) mutant non-small cell lung cancer (NSCLC). However, it is unclear whether aumolertinib combined with ionizing radiation (IR) has potential therapeutic effects in treating brain metastases (BM) tumors from NSCLC. This study explored the anti-tumor effects of aumolertinib combined with IR in epidermal growth factor receptor mutated (EGFRm) NSCLC BM tumors. First, we established a xenograft model of NSCLC BM tumors in BALB/c nude mice and assessed the anti-tumor effects of this combination. Furthermore, we examined the concentrations of aumolertinib in brain tissue and blood using liquid chromatography-mass spectrometry (LC-MS); after that, we used CCK-8, colony formation, flow cytometry assay, and immunofluorescence staining to detect the effects of aumolertinib combined with IR upon PC-9 and NCI-H1975 cells, such as cell proliferation, survival, apoptosis, cycle distribution, the situation of DNA damage, and the expression levels of relevant proteins which were detected via western blotting; finally, we chose a clinical case with which to explore the clinical benefits to the EGFRm NSCLC BM patient after the treatment of the aforementioned combination. The experiments of NSCLC BM tumor animal models demonstrated that the combination enhanced the therapeutic effects and increased the intracranial accumulation of aumolertinib; the combination can inhibit cell proliferation and survival, delay the repair of DNA damage, and increase the rates of cell apoptosis and aumolertinib abrogated G2/M phase arrest, which the IR induced; the clinical study verified that the combination demonstrated better patient benefits. In conclusion, our study demonstrated that combining aumolertinib and IR has promising anti-tumor effects in EGFR-mutant NSCLC and that this combined treatment modality may be employed as a potential therapeutic strategy for EGFR-mutant NSCLC BM patients clinically.

Optimal timing and sequence of combining stereotactic radiosurgery with immune checkpoint inhibitors in treating brain metastases: clinical evidence and mechanistic basis

Recent evidence has shown that immune checkpoint inhibitors (ICIs) are efficacious for treating brain metastases of various primary tumors. However, the immunosuppressive tumor microenvironment and the blood-brain barrier (BBB) or blood-tumor barrier (BTB) essentially restrict the efficacy of ICIs. Stereotactic radiosurgery (SRS) can be a powerful ally to ICIs due to its trait of disrupting the BBB/BTB and increasing the immunogenicity of brain metastases. The combination of SRS + ICI has shown synergy in brain metastases in several retrospective studies. Nevertheless, the optimal schedule for the combination of SRS and ICI in brain metastases is yet to be determined. In this review, we summarized the current clinical and preclinical evidence on the timing and sequence of SRS + ICI to provide insight into the current state of knowledge about this important area in patient care.

Comparative Efficacy of ALK Inhibitors for Treatment-Naïve ALK-Positive Advanced Non-Small Cell Lung Cancer with Central Nervous System Metastasis: A Network Meta-Analysis

Central nervous system (CNS) metastases and acquired resistance complicate the treatment of anaplastic lymphoma kinase (ALK) rearrangement-positive (ALK-p) advanced non-small cell lung cancer (NSCLC). Thus, this review aimed to provide a comprehensive overview of brain metastasis, acquired resistance, and prospects for overcoming these challenges. A network meta-analysis of relevant phase III randomized controlled trials was performed to compare the efficacies of multiple ALK inhibitors by drug and generation in overall patients with ALK-p untreated advanced NSCLC and a subgroup of patients with CNS metastases. The primary endpoint was progression-free survival (PFS). Generation-specific comparison results showed that third-generation ALK inhibitors were significantly more effective than second-generation ALK inhibitors in prolonging the PFS of the subgroup of patients with CNS metastases. Drug-specific comparison results demonstrated that lorlatinib was the most effective in prolonging PFS, followed by brigatinib, alectinib, ensartinib, ceritinib, crizotinib, and chemotherapy. While lorlatinib was superior to brigatinib for PFS in the overall patient population, no significant difference between the two was found in the subgroup of patients with CNS metastases. These results can serve as a foundation for basic, clinical, and translational research and guide clinical oncologists in developing individualized treatment strategies for patients with ALK-p, ALK inhibitor-naive advanced NSCLC.

Therapeutic Monitoring of Orally Administered, Small-Molecule Anticancer Medications with Tumor-Specific Cellular Protein Targets in Peripheral Fluid Spaces-A Review

Orally administered, small-molecule anticancer drugs with tumor-specific cellular protein targets (OACD) have revolutionized oncological pharmacotherapy. Nevertheless, the differences in exposure to these drugs in the systemic circulation and extravascular fluid compartments have led to several cases of therapeutic failure, in addition to posing unknown risks of toxicity. The therapeutic drug monitoring (TDM) of OACDs in therapeutically relevant peripheral fluid compartments is therefore essential. In this work, the available knowledge regarding exposure to OACD concentrations in these fluid spaces is summarized. A review of the literature was conducted by searching Embase, PubMed, and Web of Science for clinical research articles and case reports published between 10 May 2001 and 31 August 2022. Results show that, to date, penetration into cerebrospinal fluid has been studied especially intensively, in addition to breast milk, leukocytes, peripheral blood mononuclear cells, peritoneal fluid, pleural fluid, saliva and semen. The typical clinical indications of peripheral fluid TDM of OACDs were (1) primary malignancy, (2) secondary malignancy, (3) mental disorder, and (4) the assessment of toxicity. Liquid chromatography-tandem mass spectrometry was most commonly applied for analysis. The TDM of OACDs in therapeutically relevant peripheral fluid spaces is often indispensable for efficient and safe treatments.

Loureiro L, Kegler A, González Soto KE, Belter B, Rössig C, Pietzsch J, Frenz M, Bachmann M, Feldmann A. Specific and safe targeting of glioblastoma using switchable and logic-gated RevCAR T cells

Glioblastoma (GBM) is still an incurable tumor that is associated with high recurrence rate and poor survival despite the current treatment regimes. With the urgent need for novel therapeutic strategies, immunotherapies, especially chimeric antigen receptor (CAR)-expressing T cells, represent a promising approach for specific and effective targeting of GBM. However, CAR T cells can be associated with serious side effects. To overcome such limitation, we applied our switchable RevCAR system to target both the epidermal growth factor receptor (EGFR) and the disialoganglioside GD2, which are expressed in GBM. The RevCAR system is a modular platform that enables controllability, improves safety, specificity and flexibility. Briefly, it consists of RevCAR T cells having a peptide epitope as extracellular domain, and a bispecific target module (RevTM). The RevTM acts as a switch key that recognizes the RevCAR epitope and the tumor-associated antigen, and thereby activating the RevCAR T cells to kill the tumor cells. However, in the absence of the RevTM, the RevCAR T cells are switched off. In this study, we show that the novel EGFR/GD2-specific RevTMs can selectively activate RevCAR T cells to kill GBM cells. Moreover, we show that gated targeting of GBM is possible with our Dual-RevCAR T cells, which have their internal activation and co-stimulatory domains separated into two receptors. Therefore, a full activation of Dual-RevCAR T cells can only be achieved when both receptors recognize EGFR and GD2 simultaneously via RevTMs, leading to a significant killing of GBM cells both in vitro and in vivo.

Advances in the Management of Central Nervous System Metastases from Breast Cancer

Central nervous system (CNS) metastases are common in breast cancer (BC) patients and are particularly relevant as new treatments for BC are prolonging survival. Here, we review advances in the treatment of CNS metastases from BC, including radiotherapy, systemic therapies, and the evolving role of immunotherapy. The use of radiotherapy and chemotherapy is the cornerstone of treatment for CNS metastases. However, new targeted therapies have recently been developed, including anti-HER2 agents and antibody-drug conjugates that have presented promising results for the treatment of these patients.