A phase II trial of PTK787/ZK 222584 in recurrent or progressive radiation and surgery refractory meningiomas

Noncoding RNA landscape and their emerging roles as biomarkers and therapeutic targets in meningioma

Meningiomas are among the most prevalent primary CNS tumors in adults, accounting for nearly 38% of all brain neoplasms. The World Health Organization (WHO) grade assigned to meningiomas guides medical care in patients and is primarily based on tumor histology and malignancy potential. Although often considered benign, meningiomas with complicated histology, limited accessibility for surgical resection, and/or higher malignancy potential (WHO grade 2 and WHO grade 3) are harder to combat, resulting in significant morbidity. With limited treatment options and no systemic therapies, it is imperative to understand meningioma tumorigenesis at the molecular level and identify novel therapeutic targets. The last decade witnessed considerable progress in understanding the noncoding RNA landscape of meningioma, with microRNAs (miRNAs) and long noncoding RNAs (lncRNAs) emerging as molecular entities of interest. This review aims to highlight the commonly dysregulated miRNAs and lncRNAs in meningioma and their correlation with meningioma progression, malignancy, recurrence, and radioresistance. The role of "key" miRNAs as biomarkers and their therapeutic potential has also been reviewed in detail. Furthermore, current and emerging therapeutic modalities for meningioma have been discussed, with emphasis on the need to identify and subsequently employ clinically relevant miRNAs and lncRNAs as novel therapeutic targets and biomarkers.

Drug target therapy and emerging clinical relevance of exosomes in meningeal tumors

Meningioma is the most common central nervous system (CNS) tumor. In recent decades, several efforts have been made to eradicate this disease. Surgery and radiotherapy remain the standard treatment options for these tumors. Drug therapy comes to play its role when both surgery and radiotherapy fail to treat the tumor. This mostly happens when the tumors are close to vital brain structures and are nonbenign. Although a wide variety of chemotherapeutic drugs and molecular targeted drugs such as tyrosine kinase inhibitors, alkylating agents, endocrine drugs, interferon, and targeted molecular pathway inhibitors have been studied, the roles of numerous drugs remain unexplored. Recent interest is growing toward studying and engineering exosomes for the treatment of different types of cancer including meningioma. The latest studies have shown the involvement of exosomes in the theragnostic of various cancers such as the lung and pancreas in the form of biomarkers, drug delivery vehicles, and vaccines. Proper attention to this new emerging technology can be a boon in finding the consistent treatment of meningioma.

Novel Advances in Treatment of Meningiomas: Prognostic and Therapeutic Implications

Meningiomas are the most frequent histotypes of tumors of the central nervous system. Their incidence is approximately 35% of all primary brain tumors. Although they have the status of benign lesions, meningiomas are often associated with a decreased quality of life due to focal neurological deficits that may be related. The optimal treatment is total resection. Histological grading is the most important prognostic factor. Recently, molecular alterations have been identified that are specifically related to particular phenotypes and, probably, are also responsible for grading, site, and prognostic trend. Meningiomas recur in 10-25% of cases. In these cases, and in patients with atypical or anaplastic meningiomas, the methods of approach are relatively insufficient. To date, data on the molecular biology, genetics, and epigenetics of meningiomas are insufficient. To achieve an optimal treatment strategy, it is necessary to identify the mechanisms that regulate tumor formation and progression. Combination therapies affecting multiple molecular targets are currently opening up and have significant promise as adjuvant therapeutic options. We review the most recent literature to identify studies investigating recent therapeutic treatments recently used for meningiomas.

Interdisciplinary Therapeutic Approaches to Atypical and Malignant Meningiomas

Meningiomas have the highest incidence among brain tumors. In contrast to benign tumors that constitute the majority of this tumor entity, the treatment of aggressive meningiomas (WHO Grade 2 and 3) is more challenging, requiring gross total removal of the tumor and the affected dura and adjuvant radiotherapy. Sometimes the location and/or the configuration of the tumor do not favor radical surgical resection without endangering the patient's clinical condition after surgery and pharmacological therapy has, until now, not been proven to be a reliable alternative. Discussion: In this narrative review, we discuss the current literature with respect to the management of meningiomas, discussing the importance of the grade of resection in the overall prognosis of the patient and in the planning of adjuvant therapy. Conclusions: According to the location and size of the tumor, radical resection should be taken into consideration. In patients with aggressive meningiomas, adjuvant radiotherapy should be performed after surgery. In cases of skull base meningiomas, a maximal, though safe, resection should take place before adjuvant therapy. An interdisciplinary approach is beneficial for patients with primary or recurrent meningioma.

The role of radiation therapy and systemic treatments in meningioma: The present and the future

Meningiomas are the most prevalent tumors of the central nervous system. Their standard treatment is surgery, which can be curative. Adjuvant radiotherapy treatment is reserved for newly diagnosed cases of grade II and grade III meningiomas in cases of recurrent disease or when surgery is not radical or feasible. However, around 20% of these patients cannot undergo further surgical and/or radiotherapy treatment. Systemic oncological therapy can find its place in this setting. Several tyrosine kinase inhibitors have been tested (gefitinib, erlotinib, sunitinib) with unsatisfactory or negative results. Bevacizumab has shown encouraging results in these settings of patients. Immunotherapy with immune checkpoint inhibitors has reported interesting results with modest objective response rates. Several ongoing studies are assessing different target therapies and multimodal therapies; the results are to be disclosed. Not only a better understanding of the molecular characteristics in meningiomas has allowed the gathering of more information regarding pathogenesis and prognosis, but in addition, the availability of new target therapy, immunotherapy, and biological drugs has widened the scope of potentially effective treatments in this patient population. The aim of this review was to explore the radiotherapy and systemic treatments of meningioma with an analysis of ongoing trials and future therapeutic perspectives.

Medical Management of Meningiomas

Meningiomas represent the most common type of benign tumor of the extra-axial compartment. Although most meningiomas are benign World Health Organization (WHO) grade 1 lesions, the increasingly prevalent of WHO grade 2 lesion and occasional grade 3 lesions show worsened recurrence rates and morbidity. Multiple medical treatments have been evaluated but show limited efficacy. We review the status of medical management in meningiomas, highlighting successes and failures of various treatment options. We also explore newer studies evaluating the use of immunotherapy in management.

Advances in the systemic therapy for recurrent meningiomas and the challenges ahead

INTRODUCTION

Meningiomas represent the most common primary neoplasms of the central nervous system (CNS). 20% present with atypical (WHO grade II) or malignant (grade III) meningiomas, which show aggressive biologic behavior and high recurrence. Although surgical resection and radiation therapy are the primary treatment options for these tumors, there is a subgroup of patients who do not respond well to or are poor candidates for these approaches, leading to the exploration of systemic therapies as an alternative.

AREAS COVERED

The literature on different therapeutic groups of systemic drugs for recurrent meningiomas is reviewed, with a focus on the different molecular targets. Past and current ongoing clinical trials are also discussed.

EXPERT OPINION

To date, there is no recognized treatment that has demonstrated a substantial increase in progression-free or overall survival rates. Nonetheless, therapies targeting anti-VEGF have exhibited more encouraging results in general. The examination of genomic and epigenomic traits of meningiomas, along with the integration of molecular markers into the latest WHO tumor grading system, has provided valuable insights. This has opened avenues for exploring numerous intracellular and extracellular pathways, as well as mutations, that have been targeted in ongoing clinical trials.

Innovative treatments for meningiomas

Multi-recurrent high-grade meningiomas remain an unmet medical need in neuro-oncology when iterative surgeries and radiation therapy sessions fail to control tumor growth. Nevertheless, the last 10years have been marked by multiple advances in the comprehension of meningioma tumorigenesis via the discovery of new driver mutations, the identification of activated intracellular signaling pathways, and DNA methylation analyses, providing multiple potential therapeutic targets. Today, Anti-VEGF and mTOR inhibitors are the most used and probably the most active drugs in aggressive meningiomas. Peptide radioactive radiation therapy aims to target SSTR2A receptors, which are strongly expressed in meningiomas, but have an insufficient effect in most aggressive meningiomas, requiring the development of new techniques to increase the dose applied to the tumor. Based on the multiple potential intracellular targets, multiple targeted therapy clinical trials targeting Pi3K-Akt-mTOR and MAP kinase pathways as well as cell cycle and particularly, cyclin D4-6 are ongoing. Recently discovered driver mutations, SMO, Akt, and PI3KCA, offer new targets but are mostly observed in benign meningiomas, limiting their clinical relevance mainly to rare aggressive skull base meningiomas. Therefore, NF2 mutation remains the most frequent mutation and main challenging target in high-grade meningioma. Recently, inhibitors of focal adhesion kinase (FAK), which is involved in tumor cell adhesion, were tested in a phase 2 clinical trial with interesting but insufficient activity. The Hippo pathway was demonstrated to interact with NF2/Merlin and could be a promising target in NF2-mutated meningiomas with ongoing multiple preclinical studies and a phase 1 clinical trial. Recent advances in immune landscape comprehension led to the proposal of the use of immunotherapy in meningiomas. Except in rare cases of MSH2/6 mutation or high tumor mass burden, the activity of PD-1 inhibitors remains limited; however, its combination with various radiation therapy modalities is particularly promising. On the whole, therapeutic management of high-grade meningiomas is still challenging even with multiple promising therapeutic targets and innovations.

Docetaxel targets aggressive methylation profiles and serves as a radiosensitizer in high-risk meningiomas

BACKGROUND

Meningioma is the most common primary intracranial tumor in adults. A subset of these tumors recur and invade the brain, even after surgery and radiation, resulting in significant disability. There is currently no standard-of-care chemotherapy for meningiomas. As genomic DNA methylation profiling can prognostically stratify these lesions, we sought to determine whether any existing chemotherapies might be effective against meningiomas with high-risk methylation profiles.

METHODS

A previously published dataset of meningioma methylation profiles was used to screen for clinically significant CpG methylation events and associated cellular pathways. Based on these results, patient-derived meningioma cell lines were used to test candidate drugs in vitro and in vivo, including efficacy in conjunction with radiotherapy.

RESULTS

We identified 981 genes for which methylation of mapped CpG sites was related to progression-free survival in meningiomas. Associated molecular pathways were cross-referenced with FDA-approved cancer drugs, which nominated Docetaxel as a promising candidate for further preclinical analyses. Docetaxel arrested growth in 17 meningioma cell sources, representing all tumor grades, with a clinically favorable IC50 values ranging from 0.3 nM to 10.7 mM. The inhibitory effects of this medication scaled with tumor doubling time, with maximal benefit in fast-growing lesions. The combination of Docetaxel and radiation therapy increased markers of apoptosis and double-stranded DNA breaks, and extended the survival of mice engrafted with meningioma cells relative to either modality alone.

CONCLUSIONS

Global patterns of DNA methylation may be informative for the selection of chemotherapies against meningiomas, and existing drugs may enhance radiation sensitivity in high-risk cases.

The Role of Pharmacotherapy in Treatment of Meningioma: A Systematic Review

The safety and efficacy of various pharmacotherapeutic regimens on refractory meningiomas have been the focus of investigations. We present a comprehensive review of the previous efforts and the current state of ongoing clinical trials. A PRISMA-compliant review of the MEDLINE and ClinicalTrial.gov databases of the National Library of Medicine were performed. The primary outcomes of interest for included articles were radiographic response, overall survival, progression-free survival, six-month progression-free survival, and adverse events. Overall, 34 completed trials and 27 ongoing clinical trials were eligible. Six-month progression-free survival was reported in 6-100% of patients in the completed studies. Hematological disorders were the most common adverse events. Of the ongoing clinical trials identified, nine studies are phase I clinical trials, eleven are phase II trials, two are phase I and II trials, one is phase II and III, and two trials do not have a designated phase. Currently, there is no effective chemotherapy for refractory or recurrent meningiomas. Several promising targeted agents have been developed and are currently being investigated in the hope of identifying novel therapeutic strategies for the treatment of this pathology.

Pharmacological Landscape of FDA-Approved Anticancer Drugs Reveals Sensitivities to Ixabepilone, Romidepsin, Omacetaxine, and Carfilzomib in Aggressive Meningiomas

PURPOSE

To date, there are no systemic treatment options for patients with recurrent or refractory meningioma.

EXPERIMENTAL DESIGN

To identify effective drugs, we performed a large-scale drug screening using FDA-approved drugs on several meningioma cell lines. The impact of the top four compounds was assessed on cell viability, proliferation, colony formation, migration, and apoptosis. In addition, the antineoplastic effects of the selected drugs were validated in a heterotopic xenograft mouse model.

RESULTS

Analyses of the viability of meningioma cells treated with 119 antineoplastic FDA-approved drugs resulted in categorization into sensitive and resistant drug-response groups based on the mean IC50 values and peak serum concentrations (Cmax) in patients. Eighty drugs, including 15 alkylating agents, 14 antimetabolites, and 13 tyrosine kinase inhibitors, were classified as resistant (IC50 > Cmax). The sensitive drug-response group (n = 29, IC50 < Cmax) included RNA/protein synthesis inhibitors, proteasome inhibitors, topoisomerase, tyrosine-kinase, and partial histone deacetylase and microtubule inhibitors. The IC50 value of the four most effective compounds (carfilzomib, omacetaxine, ixabepilone, and romidepsin) ranged from 0.12 to 9.5 nmol/L. Most of them caused cell-cycle arrest in the G2-M-phase and induced apoptosis. Furthermore, all drugs except romidepsin significantly inhibited tumor growth in vivo. The strongest antineoplastic effect was observed for ixabepilone, which reduced tumor volume by 86%.

CONCLUSIONS

In summary, a large-scale drug screening provides a comprehensive insight into the anti-meningioma activities of FDA-approved drugs, and identified carfilzomib, omacetaxine, ixabepilone, and romidepsin as novel potent antineoplastic agents for the treatment of aggressive meningiomas. The most pronounced effects were observed with ixabepilone mandating for further clinical investigation.

Emerging systemic treatment options in meningioma

PURPOSE

Meningiomas are the most frequently diagnosed intracranial neoplasms. Usually, they are treated by surgical resection in curative intent. Radiotherapy and stereotactic radiosurgery are commonly applied in the adjuvant setting in newly diagnosed atypical (CNS WHO grade 2), and anaplastic (CNS WHO grade 3) meningioma, especially if gross total resection is not feasible, and in recurrent cases. Conversely, the evidence for pharmacotherapy in meningioma is scarce.

METHODS

The available literature of systemic treatment in meningioma was screened using PubMed, and ongoing clinical trials were explored using ClinicalTrials.gov.

RESULTS

Classical cytotoxic agents, somatostatin analogs, and antihormone treatments have shown only limited efficacy. In contrast, tyrosine kinase inhibitors and monoclonal antibodies, especially those targeting angiogenic signaling such as sunitinib and bevacizumab, have shown promising antitumoral activity in small phase 2 trials. Moreover, results of recent landmark studies on (epi-)genetic alterations in meningioma revealed potential therapeutic targets which are currently under investigation. These include inhibitors of mammalian target of rapamycin (mTOR), focal adhesion kinase (FAK), cyclin-dependent kinases (CDK), phosphoinositide-3-kinase (PI3K), sonic hedgehog signaling, and histone deacetylases. In addition, clinical trials evaluating immune checkpoint inhibitors such as ipilimumab, nivolumab, pembrolizumab and avelumab are currently being conducted and early results suggest clinically meaningful responses in a subset of patients.

CONCLUSIONS

There is a paucity of high-level evidence on systemic treatment options in meningioma. However, interesting novel treatment targets have been identified in the last decade. Positive signals of anti-angiogenic agents, genomically targeted agents and immunotherapy in early phase trials should be confirmed in large prospective controlled trials.

Histone deacetylase inhibitors enhance oncolytic herpes simplex virus therapy for malignant meningioma

Approximately 20% of meningiomas are not benign (higher grade) and tend to relapse after surgery and radiation therapy. Malignant (anaplastic) meningioma (MM) is a minor subset of high-grade meningioma that is lethal with no effective treatment options currently. Oncolytic herpes simplex virus (oHSV) is a powerful anti-cancer modality that induces both direct cell death and anti-tumor immunity, and has shown activity in preclinical models of MM. However, clinically meaningful efficacy will likely entail rational mechanistic combination approaches. We here show that epigenome modulator histone deacetylase inhibitors (HDACi) increase anti-cancer effects of oHSV in human MM models, IOMM-Lee (NF2 wild-type) and CH157 (NF2 mutant). Minimally toxic, sub-micromolar concentrations of pan-HDACi, Trichostatin A and Panobinostat, substantively increased the infectability and spread of oHSV G47Δ within MM cells in vitro, resulting in enhanced oHSV-mediated killing of target cells when infected at low multiplicity of infection (MOI). Transcriptomics analysis identified selective alteration of mRNA processing and splicing modules that might underlie the potent anti-MM effects of combining HDACi and oHSV. In vivo, HDACi treatment increased intratumoral oHSV replication and boosted the capacity of oHSV to control the growth of human MM xenografts. Thus, our work supports further translational development of the combination approach employing HDACi and oHSV for the treatment of MM.

The role of bevacizumab for treatment-refractory intracranial meningiomas: a single institution's experience and a systematic review of the literature

INTRODUCTION

Meningiomas account for over 30% of all primary brain tumors. While surgery can be curative for these tumors, several factors may lead to a higher likelihood of recurrence. For recurrent meningiomas, bevacizumab may be considered as a therapeutic agent, but literature regarding its efficacy is sparse. Thus, we present a systematic review of the literature and case series of patients from our institution with treatment-refractory meningiomas who received bevacizumab.

METHODS

Patients at our institution who were diagnosed with recurrent meningioma between January 2000 and September 2020 and received bevacizumab monotherapy were included in this study. Bevacizumab duration and dosages were noted, as well as progression-free survival (PFS) after the first bevacizumab injection. A systematic review of the literature was also performed.

RESULTS

Twenty-three patients at our institution with a median age of 55 years at initial diagnosis qualified for this study. When bevacizumab was administered, 2 patients had WHO grade I meningiomas, 10 patients had WHO grade II meningiomas, and 11 patients had WHO grade III meningiomas. Median PFS after the first bevacizumab injection was 7 months. Progression-free survival rate at 6 months was 57%. Two patients stopped bevacizumab due to hypertension and aphasia. Systematic review of the literature showed limited ability for bevacizumab to control tumor growth.

CONCLUSION

Bevacizumab is administered to patients with treatment-refractory meningiomas and, though its effectiveness is limited, outperforms other systemic therapies reported in the literature. Further studies are required to identify a successful patient profile for utilization of bevacizumab.

Diagnostic and Therapeutic Strategy in Anaplastic (Malignant) Meningioma, CNS WHO Grade 3

Simple Summary

Only 1% of all meningioma diagnosis is classified as malignant (anaplastic) meningioma. Due to their rarity, clinical management of these tumors presents several gaps. In this review, we investigate current knowledge of anaplastic meningioma focusing on their pathological and radiological diagnosis, molecular assessment, and loco-regional and systemic management. Despite the current marginal role of systemic therapy, it is possible that the increasing knowledge of molecular altered pathways of the disease will lead to the development of novel effective systemic treatments.

Abstract

Background: Meningiomas are the most common primary central nervous system malignancies accounting for 36% of all intracranial tumors. However, only 1% of meningioma is classified as malignant (anaplastic) meningioma. Due to their rarity, clinical management of these tumors presents several gaps. Methods: We carried out a narrative review aimed to investigate current knowledge of anaplastic meningioma focusing on their pathological and radiological diagnosis, molecular assessment, and loco-regional and systemic management. Results: The most frequent genetic alteration occurring in meningioma is the inactivation in the neurofibromatosis 2 genes (merlin). The accumulation of copy number losses, including 1p, 6p/q, 10q, 14q, and 18p/q, and less frequently 2p/q, 3p, 4p/q, 7p, 8p/q, and 9p, compatible with instability, is restricted to NF2 mutated meningioma. Surgery and different RT approaches represent the milestone of grade 3 meningioma management, while there is a marginal role of systemic therapy. Conclusions: Anaplastic meningiomas are rare tumors, and diagnosis should be suspected and confirmed by trained radiologists and pathologists. Despite the current marginal role of systemic therapy, it is possible that the increasing knowledge of molecular altered pathways of the disease will lead to the development of novel effective systemic treatments.

Management of Recurrent Meningiomas: State of the Art and Perspectives

Simple Summary

Intracranial meningiomas account for 30% to 40% of the primary lesions of the central nervous system. Surgery is the mainstay treatment whenever symptoms related to an intra-cranial meningioma are encountered. However, the management of recurrences after initial surgery, which are not uncommon, is still a matter of debate. Here, we present the alternatives described in the management of meningioma recurrence (radiotherapy, stereotaxic radiosurgery, protontherapy, and chemotherapy, among others). Their overall results are compared to surgery and future perspectives are presented.

Abstract

Background: While meningiomas often recur over time, the natural history of repeated recurrences and their management are not well described. Should recurrence occur, repeat surgery and/or use of adjuvant therapeutic options may be necessary. Here, we summarize current practice when it comes to meningioma recurrence after initial surgical management. Methods: A total of N = 89 articles were screened. N = 41 articles met the inclusion criteria and N = 16 articles failed to assess management of meningioma recurrence. Finally, N = 24 articles were included in our review. Results: The articles were distributed as follows: studies on chemotherapy (N = 14), radiotherapy, protontherapy, and stereotaxic radiosurgery (N = 6), boron-neutron capture therapy (N = 2) and surgery (N = 3). No study seems to provide serious alternatives to surgery in terms of progression-free and overall survival. Recurrence can occur long after the initial surgery and also affects WHO grade 1 meningiomas, even after initial gross total resection at first surgery, emphasizing the need for a long-term and comprehensive follow-up. Conclusions: Surgery still seems to be the state-of-the-art management when it comes to meningioma recurrence, since none of the non-surgical alternatives show promising results in terms of progression-free and overall survival.

Advances in Molecular Biological and Translational Studies in World Health Organization Grades 2 and 3 Meningiomas: A Literature Review

The treatment of World Health Organization (WHO) grades 2 and 3 meningiomas remains difficult and controversial. The pathogenesis of high-grade meningiomas was expected to be elucidated to improve treatment strategies. The molecular biology of meningiomas has been clarified in recent years. High-grade meningiomas have been linked to NF2 mutations and 22q deletion. CDKN2A/B homozygous deletion and TERT promoter mutations are independent prognostic factors for WHO grade 3 meningiomas. In addition to 22q loss, 1p, 14p, and 9q loss have been linked to high-grade meningiomas. Meningiomas enriched in copy number alterations may be biologically invasive. Furthermore, several new comprehensive classifications of meningiomas have been proposed based on these molecular biological features, including DNA methylation status. The new classifications may have implications for treatment strategies for refractory aggressive meningiomas because they provide a more accurate prognosis compared to the conventional WHO classification. Although several systemic therapies, including molecular targeted therapies, may be effective in treating refractory aggressive meningiomas, these drugs are being tested. Systemic drug therapy for meningioma is expected to be developed in the future. Thus, this review aims to discuss the distinct genomic alterations observed in WHO grade 2 and 3 meningiomas, as well as their diagnostic and therapeutic implications and systemic drug therapies for high-grade meningiomas.

Identification and Management of Aggressive Meningiomas

Meningiomas are common primary central nervous system tumors derived from the meninges, with management most frequently entailing serial monitoring or a combination of surgery and/or radiation therapy. Although often considered benign lesions, meningiomas can not only be surgically inaccessible but also exhibit aggressive growth and recurrence. In such cases, adjuvant radiation and systemic therapy may be required for tumor control. In this review, we briefly describe the current WHO grading scale for meningioma and provide demonstrative cases of treatment-resistant meningiomas. We also summarize frequently observed molecular abnormalities and their correlation with intracranial location and recurrence rate. We then describe how genetic and epigenetic features might supplement or even replace histopathologic features for improved identification of aggressive lesions. Finally, we describe the role of surgery, radiotherapy, and ongoing systemic therapy as well as precision medicine clinical trials for the treatment of recurrent meningioma.

A multi-institutional phase II trial of bevacizumab for recurrent and refractory meningioma

Background

Systemic therapies for refractory meningiomas are limited with no FDA-approved therapeutics. Vascular endothelial growth factor (VEGF) is a signaling protein associated with neovascularization, peritumoral edema, and meningioma tumorigenesis.

Methods

This phase II study investigates the efficacy of bevacizumab (BEV), a VEGF binding monoclonal antibody, in patients with progressive Grade I (G1M), Grade II (G2M), Grade III (G3M) meningioma, and other non-parenchymal tumors including vestibular schwannoma (n = 4) and hemangiopericytoma (n = 4) with the primary endpoint of progression-free survival rate at 6-months (PFS-6). Non-meningiomas were included with the respective meningioma grade in the analysis. Secondary endpoints include median overall survival (mOS) and response rate.

Results

Fifty Patients (26 women; median age 54 years; range 23-81), 42 with progressive meningioma were treated: 10 G1M, 20 G2M, and 12 G3M. Prior treatments include surgical resection (41 patients), radiosurgery (24 patients), external beam radiotherapy (28 patients), and chemotherapy (14 patients). Median infusions administered were 16 (range, 2-68). Response was graded using the Macdonald's criteria. PFS-6, median PFS, and mOS were 87%, 22 months, 35 months for G1M; 77%, 23 months, 41 months for G2M; and 46%, 8 months, 12 months for G3M. Best radiographic responses include stable disease (G1M: 100%; G2M: 85%; G3M: 82%); partial response (G1M: 0%; G2M: 5%; G3M: 0%) and progressive disease (G1M: 0%; G2M: 10%; G3M:18%). The most common toxicities were hypertension (n = 19, 42.2%), proteinuria (n = 16, 35.6%), and fatigue (n = 14, 31.1%).

Conclusion

This study showed BEV is well tolerated and appears to be a promising systemic treatment option for patients with recurrent and refractory meningiomas.

Chemotherapy and targeted therapies for meningiomas: what is the evidence?

PURPOSE OF REVIEW

Although most meningiomas are slow growing tumors mainly controlled by surgery with or without radiotherapy, aggressive meningiomas that fail these conventional treatments constitute a rare situation, a therapeutic challenge and an unmet need in neuro-oncology.

RECENT FINDING

Mutational landscape in recurrent high-grade meningiomas includes mainly NF2 mutation or 22q chromosomal deletion, whereas telomerase reverse transcriptase promoter, BAP-1 and CDK2NA mutations were also found in aggressive meningiomas. Pi3K-Akt-mTOR pathway is currently the most relevant intracellular signaling pathway target in meningiomas with preliminary clinical activity observed. Assessment of drug activity with progression free survival rate at 6 months is challenging in regard to meningioma growth rate heterogeneity, so that 3-dimensional growth rate before and during treatment could be considered in the future to selected new active drugs.

SUMMARY

Despite a low evidence level, some systemic therapies may be considered for patients with recurrent meningioma not amenable to further surgery or radiotherapy. In recurrent high-grade meningioma, everolimus-octreotide combination, bevacizumab, sunitinib and peptide receptor radionuclide therapy exhibit a signal of activity that may justify their clinical use. Despite a lack of clear signal of activity to date, immunotherapy may offer new perspectives in the treatment of these refractory tumors.

Receptor Tyrosine Kinases as Candidate Prognostic Biomarkers and Therapeutic Targets in Meningioma

Meningioma (MGM) is the most common type of intracranial tumor in adults. The validation of novel prognostic biomarkers to better inform tumor stratification and clinical prognosis is urgently needed. Many molecular and cellular alterations have been described in MGM tumors over the past few years, providing a rational basis for the identification of biomarkers and therapeutic targets. The role of receptor tyrosine kinases (RTKs) as oncogenes, including those of the ErbB family of receptors, has been well established in several cancer types. Here, we review histological, molecular, and clinical evidence suggesting that RTKs, including the epidermal growth factor receptor (EGFR, ErbB1), as well as other members of the ErbB family, may be useful as biomarkers and therapeutic targets in MGM.

Trabectedin for recurrent WHO grade 2 or 3 meningioma: a randomized phase 2 study of the EORTC Brain Tumor Group (EORTC-1320-BTG)

BACKGROUND

No systemic treatment has been established for meningioma progressing after local therapies.

METHODS

This randomized, multicenter, open-label, phase 2 study included adult patients with recurrent WHO grade 2 or 3 meningioma. Patients were 2:1 randomly assigned to intravenous trabectedin (1.5 mg/m 2 every three weeks) or local standard of care (LOC). The primary endpoint was progression-free survival (PFS). Secondary endpoints comprised overall survival (OS), objective radiological response, safety, quality of life (QoL) assessment using the QLQ-C30 and QLQ-BN20 questionnaires, and we performed tissue-based exploratory molecular analyses.

RESULTS

Ninety patients were randomized (n=29 in LOC, n=61 in trabectedin arm). With 71 events, median PFS was 4.17 months in the LOC and 2.43 months in the trabectedin arm (hazard ratio [HR]=1.42; 80% CI, 1.00-2.03; p=0.294) with a PFS-6 rate of 29.1% (95% CI, 11.9%-48.8%) and 21.1% (95% CI, 11.3%-32.9%), respectively. Median OS was 10.61 months in the LOC and 11.37 months in the trabectedin arm (HR=0.98; 95% CI, 0.54-1.76; p=0.94). Grade ≥3 adverse events occurred in 44.4% patients in the LOC and 59% of patients in the trabectedin arm. Enrolled patients had impeded global QoL and overall functionality and high fatigue before initiation of systemic therapy. DNA methylation class, performance status, presence of a relevant co-morbidity, steroid use, and right hemisphere involvement at baseline were independently associated with OS.

CONCLUSIONS

Trabectedin did not improve PFS and OS and was associated with higher toxicity than LOC treatment in patients with non-benign meningioma. Tumour DNA methylation class is an independent prognostic factor for OS.

Discovering the Molecular Landscape of Meningioma: The Struggle to Find New Therapeutic Targets

Meningiomas are the most common primary CNS tumors. They are usually benign but can present aggressive behavior in about 20% of cases. The genetic landscape of meningioma is characterized by the presence (in about 60% of cases) or absence of NF2 mutation. Low-grade meningiomas can also present other genetic alterations, particularly affecting SMO, TRAF7, KLF4 AKT1 and PI3KCA. In higher grade meningiomas, mutations of TERT promoter and deletion of CDKN2A/B seem to have a prognostic value. Furthermore, other genetic alterations have been identified, such as BAP1, DMD and PBRM1. Different subgroups of DNA methylation appear to be correlated with prognosis. In this review, we explored the genetic landscape of meningiomas and the possible therapeutic implications.

Late Recurrence of Metastatic Meningioma in the Lung in a Patient with Endometrial Cancer: A Case Report

Patient: Female, 58-year-old

Final Diagnosis: Meningioma

Symptoms: Abdominal pain • bleeding • headache

Medication: —

Clinical Procedure: —

Specialty: Oncology

Long term follow up in 183 high grade meningioma: A single institutional experience

INTRODUCTION

Meningiomas are usually considered benign lesions, however a proportion of them shows a more aggressive behavior, defined high-grade meningiomas (HGM). Effective medical treatments are lacking, especially at the time of recurrence.

METHODS

Through a retrospective analysis, we examined epidemiological, diagnostic, therapeutic, recurrence information and survival data of HGM treated at our institution between 2010 and 2018.

RESULTS

183 patients (105 females and 78 males), with median age of 58 years (25-88), were included; 168 were atypical, 12 anaplastic, 3 rhabdoid. Overall, m-PFS was 4.2 years, and m-OS was 10.3 years. Gross-total resection had a 5-year survival rate of 95% compared with subtotal/partial resection (86% and 67%) (p = 0.002). Higher expression of Ki-67/MIB-1 seems associated with higher risk of death (HR:1.06 with 95% CI, 1.00-1.12, p = 0.03). No statistically significant differences were seen in survival between the group managed with a wait-and-see strategy vs the group treated with RT while a difference on PFS was seen (4.1 years vs 5.2 years p = 0.03). After second recurrence, the most employed treatments were systemic therapies with a very limited effect on disease control.

CONCLUSIONS

Data confirmed the aggressive behavior of HGM. The extent of resection seems to correlate with a favorable outcome regardless histological subtypes. The role of RT remains controversial, with no statistically significant impact on OS but a possible role on PFS. Recurrent HGM remains the real challenge, to date no chemotherapies are able to achieve disease control. Future research should focus on biological/molecular predictors in order to achieve a patient-tailored treatment.

Biological Treatments of Neurofibromatosis Type 2 and Other Skull Base Disorders

Studies of genomic alterations that occur in skull base tumors have provided information regarding biological aberrations that are necessary for the growth and maintenance of these tumors. This has led to the development and initiation of clinical trials incorporating biological treatments for many skull base tumors. The exciting developments of molecularly targeted therapy for the treatment of skull base tumors may provide noninvasive therapeutic options for patients that can be used either alone or in combination with surgery and/or radiation therapy. Future analysis and continued scientific discovery of treatments for skull base tumors can lead to improved outcomes in patients.

Meningioma: not always a benign tumor. A review of advances in the treatment of meningiomas

Meningiomas are the most common primary intracranial tumors. The majority of meningiomas are benign, but they can present different grades of dedifferentiation from grade I to grade III (anaplastic/malignant) that are associated with different outcomes. Radiological surveillance is a valid option for low-grade asymptomatic meningiomas. In other cases, the treatment is usually surgical, aimed at achieving a complete resection. The use of adjuvant radiotherapy is the gold standard for grade III, is debated for grade II and is not generally indicated for radically resected grade I meningiomas. The use of systemic treatments is not standardized. Here we report a review of the literature on the clinical, radiological and molecular characteristics of meningiomas, available treatment strategies and ongoing clinical trials.

Advances in Multidisciplinary Management of Skull Base Meningiomas

The surgical management of Skull Base Meningiomas (SBMs) has radically changed over the last two decades. Extensive surgery for patients with SBMs represents the mainstream treatment; however, it is often challenging due to narrow surgical corridors and proximity to critical neurovascular structures. Novel surgical technologies, including three-dimensional (3D) preoperative imaging, neuromonitoring, and surgical instruments, have gradually facilitated the surgical resectability of SBMs, reducing postoperative morbidity. Total removal is not always feasible considering a risky tumor location and invasion of surrounding structures and brain parenchyma. In recent years, the use of primary or adjuvant stereotactic radiosurgery (SRS) has progressively increased due to its safety and efficacy in the control of grade I and II meningiomas, especially for small to moderate size lesions. Patients with WHO grade SBMs receiving subtotal surgery can be monitored over time with surveillance imaging. Postoperative management remains highly controversial for grade II meningiomas, and depends on the presence of residual disease, with optional upfront adjuvant radiation therapy or close surveillance imaging in cases with total resection. Adjuvant radiation is strongly recommended in patients with grade III tumors. Although the currently available chemotherapy or targeted therapies available have a low efficacy, the molecular profiling of SBMs has shown genetic alterations that could be potentially targeted with novel tailored treatments. This multidisciplinary review provides an update on the advances in surgical technology, postoperative management and molecular profile of SBMs.

Reactor-based boron neutron capture therapy for 44 cases of recurrent and refractory high-grade meningiomas with long-term follow-up

BACKGROUND

High-grade meningioma (HGM) is difficult to treat, and recurrent HGM after radiotherapy has an especially poor prognosis. We retrospectively analyzed the cases of 44 consecutive patients with recurrent and refractory HGM who were treated by reactor-based boron neutron capture therapy (BNCT).

METHODS

In 2005-2019, we treated 44 recurrent and refractory HGMs by reactor-based BNCT. We analyzed the patients' tumor shrinkage, overall survival (OS) after initial diagnosis, OS after BNCT, progression-free survival (PFS) post-BNCT, and treatment failure patterns.

RESULTS

The median OS (mOS) after BNCT and mOS after initial diagnosis were 29.6 (95%CI: 16.1-40.4) and 98.4 (95%CI: 68.7-169.4) months, respectively. The median follow-up after BNCT was 26 (6.4-103) months. The grade 2 (20 cases) and 3 (24 cases) post-BNCT mOS values were 44.4 (95%CI: 27.4-not determined) and 21.55 (10.6-30.6) months, respectively (p=0.0009). Follow-up images were obtained from 36 cases at >3 months post-BNCT; 35 showed tumor shrinkage during the observation period. The post-BNCT median PFS (mPFS) of 36 cases was 13.7 (95%CI: 8.3-28.6) months. The post-BNCT mPFS values in patients with grade 2 and 3 disease were 24.3 (95%CI: 9.8-not determined) and 9.4 (6.3-14.4) months, respectively (p=0.0024). Local recurrence was observed in only 22.2% of cases. These results showed good local tumor control and prolonged survival for recurrent HGM cases.

CONCLUSIONS

Most of these cases had relatively large tumor volumes. The proportion of grade 3 patients was extremely high. Our patients thus seemed to have poor prognoses. Nevertheless, reactor-based BNCT exerted relatively good local control and favorable survival for recurrent and refractory HGMs.

Current experimental therapies for atypical and malignant meningiomas

INTRODUCTION

Atypical (WHO grade II) and malignant meningiomas (WHO Grade III) are a rare subset of primary intracranial tumors. Given their relatively high recurrence rate after surgical resection and radiotherapy, there has been a recent push to explore other adjuvant treatment options for these treatment-refractory tumors. Recent advances in molecular sequencing of tumors have elucidated new pathways and drug targets which are currently being studied. This article provides a thorough overview of novel investigational therapeutics including targeted therapy, immunotherapy, and new technological modalities for atypical and malignant meningiomas.

METHODS

We performed a comprehensive review of the available literature regarding preclinical and clinical evidence for emerging treatments for high grade meningiomas from 1980 to 2020 including contemporaneous clinical trials.

RESULTS

There is encouraging preclinical evidence regarding the efficacy of the emerging treatments discussed in this article. Several clinical trials are currently recruiting patients to translate targeted molecular therapy for meningiomas. Several clinical studies have suggested a clinical benefit of combinatorial treatment for these treatment-refractory tumors.

CONCLUSION

With numerous active clinical trials for high grade meningiomas, a meaningful improvement in the outcomes for these tumors may be on the horizon.

Brain-invasive meningiomas: molecular mechanisms and potential therapeutic options

Meningiomas are the most commonly diagnosed benign intracranial adult tumors. Subsets of meningiomas that present with extensive invasion into surrounding brain areas have high recurrence rates, resulting in difficulties for complete resection, substantially increased mortality of patients, and are therapeutically challenging for neurosurgeons. Exciting new data have provided insights into the understanding of the molecular machinery of invasion. Moreover, clinical trials for several novel approaches have been launched. Here, we will highlight the mechanisms which govern brain invasion and new promising therapeutic approaches for brain-invasive meningiomas, including pharmacological approaches targeting three major aspects of tumor cell invasion: extracellular matrix degradation, cell adhesion, and growth factors, as well as other innovative treatments such as immunotherapy, hormone therapy, Tumor Treating Fields, and biodegradable copolymers (wafers), impregnated chemotherapy. Those ongoing studies can offer more diversified possibilities of potential treatments for brain-invasive meningiomas, and help to increase the survival benefits for patients.

Regression of Intracranial Meningiomas Following Treatment with Cabozantinib

Recurrent meningiomas remain a substantial treatment challenge given the lack of effective therapeutic options aside from surgery and radiation therapy, which yield limited results in the retreatment situation. Systemic therapies have little effect, and responses are rare; the search for effective systemic therapeutics remains elusive. In this case report, we provide data regarding significant responses in two radiographically diagnosed intracranial meningiomas in a patient with concurrent thyroid carcinoma treated with cabozantinib, an oral multitarget tyrosine kinase inhibitor with potent activity against MET and VEGF receptor 2. Given the clinical experience supporting the role of VEGF agents as experimental therapeutics in meningioma and the current understanding of the biological pathways underlying meningioma growth, this may represent a new oral therapeutic alternative, warranting prospective evaluation.

Medical management of meningiomas

Meningiomas are the most frequently occurring primary brain tumors in adults, representing almost one-third of all primary central nervous system tumors. Several factors have been suggested as an underlying cause in the development of meningiomas, such as ionizing radiation (therapeutic or other incidental exposure), hormonal factors, and genetic predisposition syndromes. Other established factors associated with meningiomas include age, female gender, and those from non-Hispanic Black backgrounds. Though the 2016 World Health Organization Classification of Brain Tumors largely preserves the existing grading scheme for organization of meningioma, there is increasing understanding of the molecular factors underlying the development of meningioma, some of which now form the basis for active clinical investigation. The mainstay of treatment has been the combination of radiation therapy and surgery, with a limited role for systemic therapy due to low efficacy, short duration of treatment response, and lack of uniform response criteria. Similar to other primary and metastatic brain tumors, immune-based therapies hold promise and are still under investigation.

The Myth of Prometheus in metastatic meningioma to the liver: from craniotomy to hepatectomy

Metastases from intracranial meningiomas are rare, and among them, meningiomas with hepatic dissemination are extremely rare. Therefore, there are currently no guidelines for staging and treatment of metastatic disease in meningioma, a disease that is a challenge for both the clinician and the pathologist. Our literature review revealed 24 cases of liver metastases originating from intracranial meningiomas. We used them to analyze the pathological patterns of dissemination and to assess the different management strategies available, the most efficient and beneficial being surgery and chemotherapy, especially in the case of meningiomas with hepatic and∕or systemic dissemination.

An expanded analysis framework for multivariate GWAS connects inflammatory biomarkers to functional variants and disease

Multivariate methods are known to increase the statistical power to detect associations in the case of shared genetic basis between phenotypes. They have, however, lacked essential analytic tools to follow-up and understand the biology underlying these associations. We developed a novel computational workflow for multivariate GWAS follow-up analyses, including fine-mapping and identification of the subset of traits driving associations (driver traits). Many follow-up tools require univariate regression coefficients which are lacking from multivariate results. Our method overcomes this problem by using Canonical Correlation Analysis to turn each multivariate association into its optimal univariate Linear Combination Phenotype (LCP). This enables an LCP-GWAS, which in turn generates the statistics required for follow-up analyses. We implemented our method on 12 highly correlated inflammatory biomarkers in a Finnish population-based study. Altogether, we identified 11 associations, four of which (F5, ABO, C1orf140 and PDGFRB) were not detected by biomarker-specific analyses. Fine-mapping identified 19 signals within the 11 loci and driver trait analysis determined the traits contributing to the associations. A phenome-wide association study on the 19 representative variants from the signals in 176,899 individuals from the FinnGen study revealed 53 disease associations (p < 1 × 10-4). Several reported pQTLs in the 11 loci provided orthogonal evidence for the biologically relevant functions of the representative variants. Our novel multivariate analysis workflow provides a powerful addition to standard univariate GWAS analyses by enabling multivariate GWAS follow-up and thus promoting the advancement of powerful multivariate methods in genomics.

Review of Atypical and Anaplastic Meningiomas: Classification, Molecular Biology, and Management

Although the majority of meningiomas are slow-growing and benign, atypical and anaplastic meningiomas behave aggressively with a penchant for recurrence. Standard of care includes surgical resection followed by adjuvant radiation in anaplastic and partially resected atypical meningiomas; however, the role of adjuvant radiation for incompletely resected atypical meningiomas remains debated. Despite maximum treatment, atypical, and anaplastic meningiomas have a strong proclivity for recurrence. Accumulating mutations over time, recurrent tumors behave more aggressively and often become refractory or no longer amenable to further surgical resection or radiation. Chemotherapy and other medical therapies are available as salvage treatment once standard options are exhausted; however, efficacy of these agents remains limited. This review discusses the risk factors, classification, and molecular biology of meningiomas as well as the current management strategies, novel therapeutic approaches, and future directions for managing atypical and anaplastic meningiomas.

Occurrence of Fibrotic Tumor Vessels in Grade I Meningiomas Is Strongly Associated with Vessel Density, Expression of VEGF, PlGF, IGFBP-3 and Tumor Recurrence

Angiogenesis is a key feature during oncogenesis and remains a potential target of antiangiogenic therapy. While commonly described in high-grade lesions, vascularization and its correlation with prognosis in grade I meningiomas is largely unexplored. In the histological classification, not only the number but also the composition of blood vessels seems to be important. Therefore, tumor vessel density and fibrosis were correlated with clinical and imaging variables and prognosis in 295 patients with intracranial grade I meningioma. Expression of pro-angiogenic proteins within the meningiomas was investigated by proteome analyses and further validated by immunohistochemical staining. Fibrotic tumor vessels (FTV) were detected in 48% of all tumors and strongly correlated with vessel density, but not with the histopathological tumor subtype. Occurrence of FTV was correlated with a 2-fold increased risk of recurrence in both univariate and multivariate analyses. Explorative proteome analyses revealed upregulation of VEGF (vascular endothelial growth factor), PlGF (placental growth factor), and IGFBP-3 (insulin-like growth factor-binding protein-3) in tumors displaying FTV. Immunohistochemical analyses confirmed strong correlations between tumor vessel fibrosis and expression of VEGF, PlGF, and IGFBP-3. Presence of FTV was strongly associated with disruption of the arachnoid layer on preoperative MRI in univariate and multivariate analyses. In summary, the occurrence of fibrotic tumor vessels in grade I meningiomas is strongly associated with vessel density, disruption of the arachnoid layer, expression of VEGF, PlGF, IGFBP-3 and tumor recurrence.

Anti-VEGF DNA-based aptamers in cancer therapeutics and diagnostics

The vascular endothelial growth factor (VEGF) family and its receptors play fundamental roles not only in physiological but also in pathological angiogenesis, characteristic of cancer progression. Aiming at finding putative treatments for several malignancies, various small molecules, antibodies, or protein-based drugs have been evaluated in vitro and in vivo as VEGF inhibitors, providing efficient agents approved for clinical use. Due to the high clinical importance of VEGF, also a great number of anti-VEGF nucleic acid-based aptamers-that is, oligonucleotides able to bind with high affinity and specificity a selected biological target-have been developed as promising agents in anticancer strategies. Notable research efforts have been made in optimization processes of the identified aptamers, searching for increased target affinity and/or bioactivity by exploring structural analogues of the lead compounds. This review is focused on recent studies devoted to the development of DNA-based aptamers designed to target VEGF. Their therapeutic potential as well as their significance in the construction of highly selective biosensors is here discussed.

Basis for Immunotherapy for Treatment of Meningiomas

Meningiomas are common tumors that account for approximately one third of CNS tumors diagnosed every year. They are classified by the World Health Organization in grades I-III. Higher grades have an increased rate of growth, invasiveness, rate of recurrence, and worse outcomes than lower grades. Most meningiomas are grade I, while ~18% of meningiomas are grade II and III in hospital-based series. Meningiomas are typically "benign" tumors that are treated with surgery and radiation. However, when they recur or are unresectable, treatment options are very limited, especially since they are chemotherapy-resistant. Recent advances in the treatment of cancers with immunotherapy have focused on checkpoint blockade as well as other types of immunotherapy. There is emerging evidence supporting the use of immunotherapy as a potentially effective treatment strategy for meningioma patients. The immune microenvironment of meningiomas is a complex interplay of genetic alterations, immunomodulatory protein expression, and tumor-immune cell interactions. Meningiomas are known to be infiltrated by immune cells including microglia, macrophages, B-cells, and T-cells. Several mechanisms contribute to decreased an ti-tumor immune response, allowing tumor growth and evasion of the immune system. We discuss the most current knowledge on the immune micro-environment of meningiomas, preclinical findings of immunotherapy in meningiomas, meningioma immunotherapy clinical trials, and also offer insight into future prospects for immunotherapies in meningiomas.

An Overview of Managements in Meningiomas

Meningioma is the most frequent primary tumor of the central nervous system. Important advances have been achieved in the treatment of meningioma in recent decades. Although most meningiomas are benign and have a good prognosis after surgery, clinicians often face challenges when the morphology of the tumor is complicated or the tumor is close to vital brain structures. At present, the longstanding treatment strategies of meningioma are mainly surgery and radiotherapy. The effectiveness of systemic therapy, such as chemotherapy or targeted therapy, has not been confirmed by big data series, and some clinical trials are still in progress. In this review, we summarize current treatment strategies and future research directions for meningiomas.

Advances in multidisciplinary therapy for meningiomas

Surgery has long been established as the first-line treatment for the majority of symptomatic and enlarging meningiomas, and evidence for its success is derived from retrospective case series. Despite surgical resection, a subset of meningiomas display aggressive behavior with early recurrences that are difficult to treat. The decision to radically resect meningiomas and involved structures is balanced against the risk for neurological injury in patients. Radiation therapy has largely been used as a complementary and safe therapeutic strategy in meningiomas with evidence primarily stemming from retrospective, single-institution reports. Two of the first cooperative group studies (RTOG 0539 and EORTC 22042) evaluating the outcomes of adjuvant radiation therapy in higher-risk meningiomas have shown promising preliminary results. Historically, systemic therapy has resulted in disappointing results in meningiomas. However, several clinical trials are under way evaluating the efficacy of chemotherapies, such as trabectedin, and novel molecular agents targeting Smoothened, AKT1, and focal adhesion kinase in patients with recurrent meningiomas.

Histological transformation in recurrent WHO grade I meningiomas

Atypical or malignant transformation (AT/MT) has been described in WHO grade I meningiomas. Our aim was to identify predictive factors of AT/MT at recurrence. A total of N = 15 WHO grade increases were observed in N = 13 patients (0.96% of the study population, risk of transformation of 0.12% per patient-year follow-up). Patients with and without progression at recurrence were similar regarding age, gender distribution, skull-base location, bone infiltration, and Simpson grades. Recurrence-free survival was lower in patients with transformation (5 ± 4.06 years versus 7.3 ± 5.4 years; p = 0.03). Among patient age, gender, skull base location, extent of resection or post-operative RT, no predictor of AT/MT was identified, despite a follow-up of 10,524 patient-years. The annual risk of transformation of WHO grade I meningiomas was 0.12% per patient-year follow-up. Despite the important number of patients included and their extended follow-up, we did not identify any risk factor for transformation. A total of 1,352 patients with surgically managed WHO grade I meningioma from a mixed retro-and prospective database with mean follow-up of 9.2 years ± 5.7 years (0.3–20.9 years) were reviewed. Recurring tumors at the site of initial surgery were considered as recurrence.

Response assessment of meningioma: 1D, 2D, and volumetric criteria for treatment response and tumor progression

BACKGROUND

Meningiomas are the most common primary brain tumors in adults. Due to their variable growth rates and irregular tumor shapes, response assessment in clinical trials remains challenging and no standard criteria have been defined. We evaluated 1D, 2D, and volume imaging criteria to assess whether a volumetric approach might be a superior surrogate for overall survival (OS).

METHODS

In this retrospective multicenter study, we evaluated the clinical and imaging data of 93 patients with recurrent meningiomas treated with pharmacotherapy. One-dimensional (1D), 2D, and volumetric measurements of enhancing tumor on pre- and post-treatment MRI were compared at 6 and 12 months after treatment initiation. Cox proportional hazards models were used to examine the relationship between each imaging criterion and OS.

RESULTS

The median age of the patient cohort is 51 years (range 12-88), with 14 World Health Organization (WHO) grade I, 53 WHO grade II, and 26 WHO grade III meningiomas. Volumetric increase of 40% and unidimensional increase by 10 mm at 6 months and 12 months provided the strongest association with overall survival (HR = 2.58 and 3.24 respectively, p<0.01). Setting a volume change threshold above 40% did not correlate with survival. The interobserver agreement of 1D, 2D, and volume criteria is only moderate (kappa = 0.49, 0.46, 0.52, respectively). None of the criteria based on tumor size reduction were associated with OS (P > 0.09).

CONCLUSION

Compared with 1D (Response Evaluation Criteria In Solid Tumors 1.1) and 2D (Response Assessment in Neuro-Oncology) approaches, volumetric criteria for tumor progression has a stronger association with OS, although the differences were only modest. The interobserver variability is moderate for all 3 methods. Further validation of these findings in an independent patient cohort is needed.

Multicentric and diffuse recurrences of meningiomas

Background: Meningiomas recur with a rate of 10-32% at 10 years. Several features influence the risk of recurrence.Objective: To define the pathological and surgical features at risk of multicentric-diffuse versus local-peripheral recurrence.Methods: Thirty-three patients operated on for intracranial meningiomas who experienced multicentric-diffuse recurrence were retrospectively analyzed. The data of these patients were compared to those of 50 patients who experienced local-peripheral recurrence. The analyzed factors included age and sex, tumor location and shape, brain-tumor interface, entity of resection, WHO grade, Ki67 MIB1, progesterone receptor (PR) expression, number of reoperations, progression of WHO grade, and outcome.Results: Meningiomas which recurred in multicentric-diffuse pattern showed at initial surgery a significantly higher rate of flat-shaped tumors (p = .0008) and of cases with Ki67 Li ≥ 4% (p = .037) than those which recurred in localized-peripheral pattern, whereas other factors did not significantly differ. Among patients with multicentric-diffuse recurrences, 25 underwent one to three reoperations; 17 among them (66%) are alive with local tumor control or slow progression 2-25 years after the initial surgery versus only 2 out of 8 who did not undergo surgery.Conclusions: Flat-shaped meningiomas and those with Ki67 Li ≥ 4% are at higher risk of multicentric-diffuse recurrence. Multiple reoperations over a period of several years may obtain rather long survivals in selected patients with prevalent intradural, not anaplastic tumors and not too extensive dural infiltration.

Apatinib in recurrent anaplastic meningioma: a retrospective case series and systematic literature review

Up to now, no proven effective medical therapy for surgery and radiation-refractory anaplastic meningioma (AM) exists. Patients with vascular endothelial growth factor receptor 2 (VEGFR-2) positive meningiomas showed significantly shorter progression-free survival. Apatinib is a small-molecule antiangiogenic agent that selectively inhibits VEGFR-2. We report three cases of recurrent AM (VEGFR-2 positive) treated with apatinib. After apatinib treatment, the best outcome for all three patients was the partial response. The Progression-free survival was 17.3 months, 10.3 months, and 14+ months, respectively. The third patient lost follow-up after the last review. The overall survival was 28.5 months and 18 months, respectively. The main adverse events were hypertension, hand-foot syndrome, and myelosuppression. Apatinib is active in recurrent AM patients and this is the first report in the world. It is promising to launch a Phase II clinical trial of apatinib to further evaluate its efficacy on AM.

BACKGROUND

Anaplastic meningioma (AM) are rare and aggressive tumors with high recurrence rates despite optimal surgical or medical management. Up to now, no proven effective medical therapy, surgery, or radiation-refractory for AM exist. The progression-free survival (PFS) of patients with vascular endothelial growth factor receptor 2 (VEGFR-2)-positive meningiomas was significantly low. Apatinib (YN968D1) is a small-molecule antiangiogenic agent that selectively inhibits VEGFR-2.

CASE PRESENTATION

CASE #1

A 47-year-old Asian female patient with malignant meningioma underwent four operations and three radiotherapies. She was given a 500 mg apatinib daily oral treatment, and the dosage was halved to 250 mg 3 months into the treatment. According to the Response Assessment in Neuro-Oncology (RANO) evaluation criteria, the best outcome during treatment was the partial response (PR) 6 months after the treatment. The PFS was 17.3 months, whereas the overall survival (OS) was 28.5 months. The best change in the Karnofsky performance scale (KPS) was a 10-point increase. The main adverse events included anemia (grade II), thrombocytopenia (grade II), and proteinuria (grade I).

CASE #2

A 71-year-old Asian woman with AM underwent two operations and two gamma knife stereotactic radiotherapies. She was given a 500 mg apatinib daily oral treatment with a follow-up period of 18 months. apatinib was taken orally for 10 months. According to the RANO evaluation criteria, the best outcome during treatment was PR. The PFS was 10.3 months, whereas the OS was 18 months. The best change in KPS was a 20-point increase. The main adverse events included hypertension (grade II), hand-foot syndrome (grade II), and fecal ocular blood (grade II). Case #3: A 16-year-old Asian girl with AM underwent two operations and two radiotherapies. She was given a 250 mg apatinib daily oral treatment with a follow-up period of 16 months. Apatinib was taken orally for 8 months. The patient did not follow-up after the last review of the brain-enhanced magnetic resonance imaging. According to the RANO evaluation criteria, the best outcome during treatment was PR. The PFS was 14+ months, and the best change in KPS was a 10-point increase. The main adverse events included hypertension (grade I) and hand-foot syndrome (grade I).

CONCLUSION

Apatinib is actively used in treating patients with recurrent AM. A randomized trial and phase II clinical trial of this inhibitor should be performed to further evaluate its efficacy in treating malignant meningioma.

Everolimus and Octreotide for Patients with Recurrent Meningioma: Results from the Phase II CEVOREM Trial

PURPOSE

Aggressive meningiomas that progress after surgery/radiotherapy represent an unmet medical need. Strong and constant expression of SSTR2A receptors and activation of the Pi3K/Akt/mTOR pathway have been demonstrated in meningiomas. The combination of everolimus, an mTOR inhibitor, and octreotide, a somatostatin agonist, has shown additive antitumor effect in vitro. The phase II CEVOREM trial investigated the efficacy of this combination on recurrent meningiomas.

PATIENTS AND METHODS

Patients with documented recurrent tumor progression ineligible for further surgery/radiotherapy were eligible to receive octreotide (30 mg/d, day 1) and everolimus (10 mg/d, days 1-28). The primary endpoint was the 6-month progression-free survival rate (PFS6). The secondary endpoints were overall survival, response rate, tumor growth rate according to central review, and safety.

RESULTS

A total of 20 patients were enrolled, including 2 with World Health Organization (WHO) grade I tumors, 10 with WHO grade II tumors, and 8 with WHO grade III tumors; furthermore, 4 patients harbored NF2 germline mutation. The overall PFS6 was 55% [95% confidence interval (CI), 31.3%-73.5%], and overall 6- and 12-month survival rates were 90% (95% CI, 65.6%-97.4%) and 75% (95% CI, 50.0%-88.7%), respectively. A major decrease (>50%) was observed in the growth rate at 3 months in 78% of tumors. The median tumor growth rate decreased from 16.6%/3 months before inclusion to 0.02%/3 months at 3 months (P < 0.0002) and 0.48%/3 months at 6 months after treatment (P < 0.0003).

CONCLUSIONS

The combination of everolimus and octreotide was associated with clinical and radiological activity in aggressive meningiomas and warrants further studies. Decrease in the tumor volume growth rate should be considered a complementary and sensitive endpoint to select potentially effective drugs for recurrent meningiomas.

En Plaque Meningiomas: A Narrative Review

Background  En plaque meningiomas are a rare subtype of meningiomas that are frequently encountered in the spheno-orbital region. Characterized by a hyperostotic and dural invasive architecture, these tumors present unique diagnostic and treatment considerations. Objective  The authors conduct a narrative literature review of clinical reports of en plaque meningiomas to summarize the epidemiology, clinical presentation, diagnostic criteria, and treatment considerations in treating en plaque meningiomas. Additionally, the authors present a case from their own experience to illustrate its complexity and unique features. Methods  A literature search was conducted using the MEDLINE database using the following terminology in various combinations: meningioma , meningeal neoplasms, en plaque , skull base , spheno-orbital, and sphenoid wing . Only literature published in English between 1938 and 2018 was reviewed. All case series were specifically reviewed for sufficient data on treatment outcomes, and all literature was analyzed for reports of misdiagnosed cases. Conclusion  En plaque meningiomas may present with a variety of symptoms according to their location and degree of bone invasion, requiring a careful diagnostic and treatment approach. While early and aggressive surgical resection is generally accepted as the optimal goal of treatment, these lesions require an individualized approach, with further investigation needed regarding the role of new therapies.

Metastatic meningioma: Case report of a WHO grade I meningioma with liver metastases and review of the literature

Meningioma represents the most frequently diagnosed primary brain tumor, accounting for over one-third of central nervous system neoplasms. The majority of tumors are categorized as benign. However, albeit rarely, meningiomas may metastasize to distant sites. We describe a 78-year-old man with a history of recurrent World Health Organization grade I meningioma managed who presented for evaluation of weakness and urinary retention. A computed tomography scan obtained in the emergency department revealed multiple scattered low-density liver lesions. Subsequent magnetic resonance imaging showed a 5.5-centimeter heterogeneous enhancing mass with 2 smaller enhancing lesions suspicious for a primary or secondary malignant neoplasm. Microscopic examination of a tissue sample obtained via liver biopsy demonstrated a metastatic spindle cell neoplasm with histologic features compatible with a diagnosis of World Health Organization grade I transitional meningioma. The patient was referred to hematology/oncology for systemic therapy.

Medical management of meningioma in the era of precision medicine

Surgery is curative for most meningiomas, but a minority of these tumors recur and progress after resection. Initial trials of medical therapies for meningioma utilized nonspecific cytotoxic chemotherapies. The presence of hormone receptors on meningioma ushered in trials of hormone-mimicking agents. While these trials expanded clinical understanding of meningioma, they ultimately had limited efficacy in managing aggressive lesions. Subsequent detection of misregulated proteins and genomic aberrancies motivated the study of therapies targeting specific biological disturbances observed in meningioma. These advances led to trials of targeted kinase inhibitors and immunotherapies, as well as combinations of these agents together with chemotherapies. Prospective trials currently recruiting participants are testing a diverse range of medical therapies for meningioma, and some studies now require the presence of a specific protein alteration or genetic mutation as an inclusion criterion. Increasing understanding of the unique and heterogeneous nature of meningiomas will continue to spur the development of novel medical therapies for the arsenal against aggressive tumors.