PET-based response assessment criteria for diffuse gliomas (PET RANO 1.0): a report of the RANO group.

Response Assessment in Neuro-Oncology (RANO) response criteria have been established and were updated in 2023 for MRI-based response evaluation of diffuse gliomas in clinical trials. In addition, PET-based imaging with amino acid tracers is increasingly considered for disease monitoring in both clinical practice and clinical trials. So far, a standardised framework defining timepoints for baseline and follow-up investigations and response evaluation criteria for PET imaging of diffuse gliomas has not been established. Therefore, in this Policy Review, we propose a set of criteria for response assessment based on amino acid PET imaging in clinical trials enrolling participants with diffuse gliomas as defined in the 2021 WHO classification of tumours of the central nervous system. These proposed PET RANO criteria provide a conceptual framework that facilitates the structured implementation of PET imaging into clinical research and, ultimately, clinical routine. To this end, the PET RANO 1.0 criteria are intended to encourage specific investigations of amino acid PET imaging of gliomas.

Updates for newly diagnosed and recurrent glioblastoma: a review of recent clinical trials.

PURPOSE OF REVIEW: Glioblastoma (GBM) is the most common and devastating primary malignant brain tumor. We summarize recent advances in radiotherapy, immunotherapy, and targeted therapy approaches for the treatment of newly diagnosed and recurrent glioblastoma. We also introduce ongoing clinical trials. RECENT FINDINGS: Recent clinical trials have explored multiple novel strategies to treat GBM including the use of oncoviruses, chimeric antigen receptor (CAR) T cell therapy, vaccines, radiotherapy, and novel drug delivery techniques to improves drug penetrance across the blood brain barrier. Approaches to improve drug delivery to brain tumors have the potential to expand treatment options of existing therapies that otherwise have poor brain tumor penetrance. Immunotherapy has been of keen interest in both newly diagnosed and recurrent glioblastoma. Vaccines SurVaxM and DCVax-L have shown initial promise in phase II and III trials, respectively. CAR T cell therapy trials are in their early phases but hold promise in both newly diagnosed and recurrent glioblastoma. SUMMARY: Although progress to improve outcomes for GBM patients has been modest, multiple novel strategies utilizing combination therapies, focused ultrasound to improve drug delivery, and novel immunotherapies are underway.

Prolonged complete response to adjuvant tepotinib in a patient with newly diagnosed disseminated glioblastoma harboring mesenchymal-epithelial transition fusion.

The prognosis of patients with glioblastoma (GBM) remains poor despite current treatments. Targeted therapy in GBM has been the subject of intense investigation but has not been successful in clinical trials. The reasons for the failure of targeted therapy in GBM are multifold and include a lack of patient selection in trials, the failure to identify driver mutations, and poor blood-brain barrier penetration of investigational drugs. Here, we describe a case of a durable complete response in a newly diagnosed patient with GBM with leptomeningeal dissemination and PTPRZ1-MET fusion who was treated with tepotinib, a brain-penetrant MET inhibitor. This case of successful targeted therapy in a patient with GBM demonstrates that early molecular testing, identification of driver molecular alterations, and treatment with brain-penetrant small molecule inhibitors have the potential to change the outcome in select patients with GBM.

Strategies to Improve Drug Delivery Across the Blood-Brain Barrier for Glioblastoma.

PURPOSE OF REVIEW: Glioblastoma remains resistant to most conventional treatments. Despite scientific advances in the past three decades, there has been a dearth of effective new treatments. New approaches to drug delivery and clinical trial design are needed. RECENT FINDINGS: We discuss how the blood-brain barrier and tumor microenvironment pose challenges for development of effective therapies for glioblastoma. Next, we discuss treatments in development that aim to overcome these barriers, including novel drug designs such as nanoparticles and antibody-drug conjugates, novel methods of drug delivery, including convection-enhanced and intra-arterial delivery, and novel methods to enhance drug penetration, such as blood-brain barrier disruption by focused ultrasound and laser interstitial thermal therapy. Lastly, we address future opportunities, positing combination therapy as the best strategy for effective treatment, neoadjuvant and window-of-opportunity approaches to simultaneously enhance therapeutic effectiveness with interrogation of on-treatment biologic endpoints, and adaptive platform and basket trials as imperative for future trial design. New approaches to GBM treatment should account for the blood-brain barrier and immunosuppression by improving drug delivery, combining treatments, and integrating novel clinical trial designs.

Current drug development and trial designs in neuro-oncology: report from the first American Society of Clinical Oncology and Society for Neuro-Oncology Clinical Trials Conference.

Successful drug development for people with cancers of the CNS has been challenging. There are multiple barriers to successful drug development including biological factors, rarity of the disease, and ineffective use of clinical trials. Based upon a series of presentations at the First Central Nervous System Clinical Trials Conference hosted by the American Society of Clinical Oncology and the Society for Neuro-Oncology, we provide an overview on drug development and novel trial designs in neuro-oncology. This Review discusses the challenges of therapeutic development in neuro-oncology and proposes strategies to improve the drug discovery process by enriching the pipeline of promising therapies, optimising trial design, incorporating biomarkers, using external data, and maximising efficacy and reproducibility of clinical trials.

"De novo replication repair deficient glioblastoma, IDH-wildtype" is a distinct glioblastoma subtype in adults that may benefit from immune checkpoint blockade.

Glioblastoma is a clinically and molecularly heterogeneous disease, and new predictive biomarkers are needed to identify those patients most likely to respond to specific treatments. Through prospective genomic profiling of 459 consecutive primary treatment-naïve IDH-wildtype glioblastomas in adults, we identified a unique subgroup (2%, 9/459) defined by somatic hypermutation and DNA replication repair deficiency due to biallelic inactivation of a canonical mismatch repair gene. The deleterious mutations in mismatch repair genes were often present in the germline in the heterozygous state with somatic inactivation of the remaining allele, consistent with glioblastomas arising due to underlying Lynch syndrome. A subset of tumors had accompanying proofreading domain mutations in the DNA polymerase POLE and resultant "ultrahypermutation". The median age at diagnosis was 50 years (range 27-78), compared with 63 years for the other 450 patients with conventional glioblastoma (p < 0.01). All tumors had histologic features of the giant cell variant of glioblastoma. They lacked EGFR amplification, lacked combined trisomy of chromosome 7 plus monosomy of chromosome 10, and only rarely had TERT promoter mutation or CDKN2A homozygous deletion, which are hallmarks of conventional IDH-wildtype glioblastoma. Instead, they harbored frequent inactivating mutations in TP53, NF1, PTEN, ATRX, and SETD2 and recurrent activating mutations in PDGFRA. DNA methylation profiling revealed they did not align with known reference adult glioblastoma methylation classes, but instead had unique globally hypomethylated epigenomes and mostly classified as "Diffuse pediatric-type high grade glioma, RTK1 subtype, subclass A". Five patients were treated with immune checkpoint blockade, four of whom survived greater than 3 years. The median overall survival was 36.8 months, compared to 15.5 months for the other 450 patients (p < 0.001). We conclude that "De novo replication repair deficient glioblastoma, IDH-wildtype" represents a biologically distinct subtype in the adult population that may benefit from prospective identification and treatment with immune checkpoint blockade.

Multiplatform molecular analyses refine classification of gliomas arising in patients with neurofibromatosis type 1.

Gliomas arising in the setting of neurofibromatosis type 1 (NF1) are heterogeneous, occurring from childhood through adulthood, can be histologically low-grade or high-grade, and follow an indolent or aggressive clinical course. Comprehensive profiling of genetic alterations beyond NF1 inactivation and epigenetic classification of these tumors remain limited. Through next-generation sequencing, copy number analysis, and DNA methylation profiling of gliomas from 47 NF1 patients, we identified 2 molecular subgroups of NF1-associated gliomas. The first harbored biallelic NF1 inactivation only, occurred primarily during childhood, followed a more indolent clinical course, and had a unique epigenetic signature for which we propose the terminology "pilocytic astrocytoma, arising in the setting of NF1". The second subgroup harbored additional oncogenic alterations including CDKN2A homozygous deletion and ATRX mutation, occurred primarily during adulthood, followed a more aggressive clinical course, and was epigenetically diverse, with most tumors aligning with either high-grade astrocytoma with piloid features or various subclasses of IDH-wildtype glioblastoma. Several patients were treated with small molecule MEK inhibitors that resulted in stable disease or tumor regression when used as a single agent, but only in the context of those tumors with NF1 inactivation lacking additional oncogenic alterations. Together, these findings highlight recurrently altered pathways in NF1-associated gliomas and help inform targeted therapeutic strategies for this patient population.

Imaging Primer on Chimeric Antigen Receptor T-Cell Therapy for Radiologists.

Chimeric antigen receptor (CAR) T-cell therapy is a recently approved breakthrough treatment that has become a new paradigm in treatment of recurrent or refractory B-cell lymphomas and pediatric or adult acute lymphoid leukemia. CAR T cells are a type of cellular immunotherapy that artificially enhances T cells to boost eradication of malignancy through activation of the native immune system. The CAR construct is a synthetically created functional cell receptor grafted onto previously harvested patient T cells, which bind to preselected tumor-associated antigens and thereby activate host immune signaling cascades to attack tumor cells. Advantages include a single treatment episode of 2-3 weeks and durable disease elimination, with remission rates of over 80%. Responses to therapy are more rapid than with conventional chemotherapy or immunotherapy, with intervening short-interval edema. CAR T-cell administration is associated with therapy-related toxic effects in a large percentage of patients, notably cytokine release syndrome, immune effect cell-associated neurotoxicity syndrome, and infections related to immunosuppression. Knowledge of the expected evolution of therapy response and potential adverse events in CAR T-cell therapy and correlation with the timeline of treatment are important to optimize patient care. Some toxic effects are radiologically evident, and familiarity with their imaging spectrum is key to avoiding misinterpretation. Other clinical toxic effects may be occult at imaging and are diagnosed on the basis of clinical assessment. Future directions for CAR T-cell therapy include new indications and expanded tumor targets, along with novel ways to capture T-cell activation with imaging. An invited commentary by Ramaiya and Smith is available online. Online supplemental material is available for this article. ©RSNA, 2022.

Blood-brain barrier opening with low intensity pulsed ultrasound for immune modulation and immune therapeutic delivery to CNS tumors.

INTRODUCTION: Opening of the blood-brain barrier (BBB) by pulsed low intensity ultrasound has been developed during the last decade and is now recognized as a safe technique to transiently and repeatedly open the BBB. This non- or minimally invasive technique allows for a targeted and uniform dispersal of a wide range of therapeutic substances throughout the brain, including immune cells and antibodies. METHODS: In this review article, we summarize pre-clinical studies that have used BBB-opening by pulsed low intensity ultrasound to enhance the delivery of immune therapeutics and effector cell populations, as well as several recent clinical studies that have been initiated. Based on this analysis, we propose immune therapeutic strategies that are most likely to benefit from this strategy. The literature review and trial data research were performed using Medline/Pubmed databases and clinical trial registry www.clinicaltrials.gov . The reference lists of all included articles were searched for additional studies. RESULTS: A wide range of immune therapeutic agents, including small molecular weight drugs, antibodies or NK cells, have been safely and efficiently delivered to the brain with pulsed low intensity ultrasound in preclinical models, and both tumor control and increased survival have been demonstrated in different types of brain tumor models in rodents. Ultrasound-induced BBB disruption may also stimulate innate and cellular immune responses. CONCLUSIONS: Ultrasound BBB opening has just recently entered clinical trials with encouraging results, and the association of this strategy with immune therapeutics creates a new field of brain tumor treatment.

Strontium isotope ratios related to childhood mobility: Revisiting sampling strategies of the calcined human pars petrosa ossis temporalis.

RATIONALE: Strontium isotope analysis can be applied to the calcined human otic capsule in the petrous part (pars petrosa ossis temporalis; PP) to gain information on childhood mobility in archaeological and forensic contexts. However, only a thin layer of the otic capsule, the inner cortex, demonstrates virtually no remodelling. This paper proposes an improved sampling method for the accurate sampling of the inner cortex of the otic capsule to ensure that 87 Sr/86 Sr ratios related to early childhood are obtained. METHODS: Calcined rib and diaphyseal fragments and PP from ten cremation deposits are sampled for strontium isotope analysis, whereby our improved sampling strategy is applied to sample the inner cortex of the otic capsule. This allows inter- and intraskeletal 87 Sr/86 Sr comparison within an Iron Age collection from Oss, The Netherlands. RESULTS: Forty percent (4/10) of the calcined PP that were evaluated for this study show marked differences in 87 Sr/86 Sr (0.00035-0.00065) between the inner cortex and the bone sample surrounding this layer, the external cortex that has higher remodelling rates. Differences in 87 Sr/86 Sr between various skeletal elements also aided in the identification of the minimum number of individuals. CONCLUSIONS: Our study demonstrates the problematic nature of the external cortex and stresses the need for a precise sampling method of the correct areas of the otic capsule. This can only be obtained by cutting the calcined PP midmodiolarly to enable adequate combustion degree assessment, and the correct identification and sampling of the inner cortex of the otic capsule.

Immunotherapy for Neuro-oncology.

Immunotherapy has changed the landscape of treatment of many solid and hematological malignancies and is at the forefront of cancer breakthroughs. Several circumstances unique to the central nervous system (CNS) such as limited space for an inflammatory response, difficulties with repeated sampling, corticosteroid use for management of cerebral edema, and immunosuppressive mechanisms within the tumor and brain parenchyma have posed challenges in clinical development of immunotherapy for intracranial tumors. Nonetheless, the success of immunotherapy in brain metastases (BMs) from solid cancers such as melanoma and non-small cell lung cancer (NSCLC) proves that the CNS is not an immune-privileged organ and is capable of initiating and regulating immune responses that lead to tumor control. However, the development of immunotherapeutics for the most malignant primary brain tumor, glioblastoma (GBM), has been challenging due to systemic and profound tumor-mediated immunosuppression unique to GBM, intratumoral and intertumoral heterogeneity, and lack of stably expressed clonal antigens. Here, we review recent advances in the field of immunotherapy for neuro-oncology with a focus on BM, GBM, and rare CNS cancers.

Neurologic Toxicities of Immunotherapy.

Immunotherapy has revolutionized treatment of cancer over the past two decades. The antitumor effects of immunotherapy approaches are at the expense of growing spectrum of immune-related adverse events (irAEs) due to cross-reactivity between the tumor and normal host tissue. These adverse events can happen in any organ and range from mild to severe and even life-threatening conditions. While neurological irAEs associated with immune checkpoint inhibitors (CPIs) are rare, they pose a significant challenge in management as the clinical phenotypes are heterogenous and frequently necessitate cessation of therapy and systemic immune suppression and lead to transient functional decline. On the other hand, immune effector cell-associated neurotoxicity (ICANS) is common, frequently occurs in conjunction with cytokine release syndrome (CRS), and poses a significant clinical challenge to the development and widespread use of these effective therapies. Early recognition of these neurological syndromes, timely diagnosis, and thoughtful management are key for further clinical development of these effective therapies in cancer patients. Here, we describe clinical phenotypes of CPI-induced neurological complications and ICANS and discuss steps in clinical monitoring, diagnosis, and effective management.

Long-term survival among 5-year survivors of adolescent and young adult cancer.

BACKGROUND: Although there are a growing number of survivors of adolescent and young adult (AYA) cancer, to the authors' knowledge the long-term overall survival (OS) patterns for AYA cancer survivors are underreported. The objective of the current study was to assess the long-term survival of AYA cancer survivors and identify factors associated with diminished long-term survival. METHODS: The authors used The University of Texas MD Anderson Cancer Center's tumor registry to identify 5-year survivors of cancer diagnosed as AYAs (ages 15-39 years) between the years 1970 and 2005, and who were alive 5 years after diagnosis. Kaplan-Meier curves were used to estimate OS rates over time, and Cox proportional hazards models were fitted to evaluate the association of covariates with OS. RESULTS: The authors identified 16,728 individuals who were 5-year survivors of cancer and were diagnosed as AYAs with a median follow-up of 20.0 years. The 10-year, 20-year, and 25-year OS rates were 86% (95% confidence interval [95% CI], 85%-86%), 74% (95% CI, 73%-75%), and 68% (95% CI, 67%-68%), respectively, all of which were lower than the age-adjusted estimated survival rates of the general population. Long-term OS improved for AYAs diagnosed between 2000 and 2005 compared with those diagnosed in the prior decades (P < .001). Older age at the time of diagnosis, receipt of radiation, and diagnoses including central nervous system tumors and breast cancer each were associated with diminished long-term survival. CONCLUSIONS: AYA cancer survivors have inferior long-term survival compared with the general population. Studies investigating the prevalence and types of late treatment effects and causes of death among AYA survivors are needed to more accurately identify AYAs who are at highest risk of early or late mortality.

Neurologic Toxicities of Cancer Immunotherapies: a Review.

PURPOSE OF REVIEW: This review provides clinical characterization and approach to management of neurotoxicities associated with checkpoint inhibitor therapy and chimeric antigen receptor T cell (CAR T cell) therapy. RECENT FINDINGS: Immuno-oncology has revolutionized cancer treatment. The immunomodulatory effect of these treatments extends beyond the targeted cancers; however, with a range of immune-mediated toxicities being associated with these therapies. Both the peripheral and central nervous system are vulnerable to these toxicities, with several distinct clinical syndromes strongly associated with specific immunotherapies. Neurologic immune-related adverse events are significant sequelae of both checkpoint inhibitors and CAR T cell therapy. In addition to clinical characterization of these syndromes, an understanding of the biologic underpinnings of these sequelae is essential. This will facilitate identification of patients at risk of these toxicities, develop treatments to prevent them and identify more effective clinical treatment when they occur.

Immunotherapy for Neuro-Oncology.

Immunotherapy has changed the landscape of treatment of many solid and hematological malignancies and is at the forefront of cancer breakthroughs. Several circumstances unique to the central nervous system (CNS) such as limited space for an inflammatory response, difficulties with repeated sampling, corticosteroid use for management of cerebral edema, and immunosuppressive mechanisms within the tumor and brain parenchyma have posed challenges in clinical development of immunotherapy for intracranial tumors. Nonetheless, the success of immunotherapy in brain metastases (BMs) from solid cancers such as melanoma and non-small cell lung cancer (NSCLC) proves that the CNS is not an immune-privileged organ and is capable of initiating and regulating immune responses that lead to tumor control. However, the development of immunotherapeutics for the most malignant primary brain tumor, glioblastoma (GBM), has been challenging due to systemic and profound tumor-mediated immunosuppression unique to GBM, intratumoral and intertumoral heterogeneity, low mutation burden, and lack of stably expressed clonal antigens. Here, we review recent advances in the field of immunotherapy for neuro-oncology with a focus on BM and GBM.

Role of Neutrophils and Myeloid-Derived Suppressor Cells in Glioma Progression and Treatment Resistance.

Recent efforts in brain tumor research have been directed towards the modulation of the immune system for therapeutic interventions. Several human cancers, including gliomas, are infiltrated with immune cell types-including neutrophils and myeloid-derived suppressor cells-that contribute to tumor progression, invasiveness, and treatment resistance. The role of tumor-associated neutrophils and myeloid-derived suppressor cells in cancer biology remains elusive, as these cells can exert a multitude of pro-tumor and antitumor effects. In this review, we provide the current understanding and novel insights on the role of neutrophils and myeloid-derived suppressor cells in glioma progression and treatment resistance, as well as the mechanisms of pleiotropic behaviors in these cells during disease progression, with an emphasis on possible strategies to reprogram these cells towards their antitumor actions.

Phase 1 lead-in to a phase 2 factorial study of temozolomide plus memantine, mefloquine, and metformin as postradiation adjuvant therapy for newly diagnosed glioblastoma.

BACKGROUND: Repurposed memantine, mefloquine, and metformin have putative anticancer activity. The objective of this phase 1 study was to determine the maximum tolerated doses (MTDs) of combinations of these agents with temozolomide (TMZ). METHODS: Adults with newly diagnosed glioblastoma who completed chemoradiation were eligible. The patients were assigned to receive doublet, triplet, or quadruplet therapy with TMZ combined with mefloquine, memantine, and/or metformin. Dose-limiting toxicities (DLTs) were determined, using a 3 + 3 study design. RESULTS: Of 85 enrolled patients, 4 did not complete cycle 1 (the DLT observation period) for nontoxicity reasons, and 81 were evaluable for DLT. The MTDs for doublet therapy were memantine 20 mg twice daily, mefloquine 250 mg 3 times weekly, and metformin 850 mg twice daily. For triplet therapy, the MTDs were memantine 10 mg twice daily, mefloquine 250 mg 3 times weekly, and metformin 850 mg twice daily. For quadruplet therapy, the MTDs were memantine 10 mg twice daily, mefloquine 250 mg 3 times weekly, and metformin 500 mg twice daily. DLTs included dizziness (memantine) and gastrointestinal effects (metformin). Lymphopenia was the most common adverse event (66%). From study entry, the median survival was 21 months, and the 2-year survival rate was 43%. CONCLUSIONS: Memantine, mefloquine, and metformin can be combined safely with TMZ in patients with newly diagnosed glioblastoma.

The path forward for anti-programmed cell death-1 therapy in gliomas.

PURPOSE OF REVIEW: Checkpoint inhibitors (CPIs) represent the forefront of novel immunotherapeutic approaches for the treatment of solid cancers. However, the clinical development of CPIs in glioblastoma (GBM) has been challenging owing to an immunosuppressive tumor microenvironment and, possibly, low tumor mutation burden. Here, we review possible mechanisms responsible for the success of programmed cell death-1 (PD-1) blockade in patients with hypermutated GBM, recent clinical trials of anti-PD-1 monotherapy, trials incorporating neoadjuvant strategies, and trials of immunotherapy combination approaches in GBM. Mechanisms of resistance to immunotherapy and methods to overcome these challenges are also discussed. RECENT FINDINGS: Although two large phase III trials failed to demonstrate the superior efficacy of CPI in comparison with the standard of care in newly diagnosed and recurrent GBM, recent studies suggest that opportunities exist in some patients with GBM. A phase II study showed longer survival in patients with recurrent GBM who received neoadjuvant anti-PD-1 therapy than in those who received it as adjuvant therapy. In addition, cases of response to anti-PD-1 therapy in GBM patients with clonal hypermutator tumors have been reported. SUMMARY: Even though anti-PD-1 therapy does not seem to provide a benefit for molecularly unselected GBM patients, the success of PD-1 blockade in certain subsets of patients is encouraging.

Treatment strategies for glioblastoma in older patients: age is just a number.

BACKGROUND/PURPOSE: Optimal care for elderly patients with glioblastoma (GBM) remains in question due to their exclusion from and underrepresentation in many clinical trials (including EORTC 22,981) as well as their historically poor overall survival. METHODS: A retrospective chart review was conducted at a single high-volume cancer center for newly diagnosed elderly (65 years old or older) GBM patients diagnosed from 2011 through 2017. RESULTS: A total of 158 newly diagnosed GBM patients aged 65 years and older were identified. One hundred forty-four patients (91.1%) received radiotherapy (RT) and 130 patients (90.3%) received concurrent temozolomide with RT. Sixty-one patients (38.6%) completed concurrent chemoradiation and 6 cycles of adjuvant temozolomide. 23% of patients discontinued temozolomide during concurrent or adjuvant treatment due to side effects or complications of chemotherapy. With a median follow-up time of 35.0 months, median overall survival (OS) time for the full cohort was 18.6 months, with estimated OS rates of 74.8%, 35.9%, and 9.5% at 1, 2, and 5 years, respectively. On multivariable analysis, higher KPS (p = 0.002, HR 0.46; 95% CI 0.63-0.82), completing planned RT course (p = 0.01, HR 0.29; 95% CI 0.11-0.75), and completing 6 cycles of adjuvant temozolomide (p = 0.01, HR 2.62; 95% CI 1.67-4.12) were independently associated with improved OS. CONCLUSIONS: Our cohort of elderly GBM patients was predominantly treated with standard of care therapy based on EORTC 22,981. Despite their age, these patients generally tolerated treatment well and had favorable outcomes compared to those reported for patients treated on EORTC 22,981. Based on these findings, using advanced age as the basis for treatment de-escalation or as an exclusionary criterion in clinical trials should be discouraged.