Mifepristone (RU 486) treatment of meningiomas

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.

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.

Management of Atypical and Anaplastic Meningiomas

Meningiomas are the most prevalent primary tumor of central nervous system origin, and although most of these neoplasms are benign, a small proportion exemplifies an aggressive profile characterized by high recurrence rates, pleomorphic histology, and overall resistance to standard treatment. Standard initial therapy for malignant meningiomas includes maximal safe surgical resection followed by focal radiation. The role for chemotherapy during recurrence of these aggressive meningiomas is less clear. Prognosis is poor, and recurrence of malignant meningiomas is high. This article provides an overview of atypical and anaplastic "malignant" meningiomas, their treatment, and ongoing research looking for more effective treatments.

Novel Medical Therapies in Meningiomas

Meningiomas are the most common primary brain tumor in adults and have been historically managed with surgery and radiation therapy. However, in patients with inoperable, recurrent or high-grade tumors, medical therapy is often needed. Traditional chemotherapy and hormone therapy have been largely ineffective. However, with improved understanding of the molecular drivers in meningioma, there has been increasing interest in targeted molecular and immune therapies. In this chapter, we will discuss recent advances in meningioma genetics and biology and review current clinical trials with targeted molecular treatment and other novel therapies.

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.

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.

The risk of developing a meningioma during and after pregnancy

Pregnancy has been associated with diagnosis or growth of meningiomas in several case reports, which has led to the hypothesis that pregnancy may be a risk factor for meningiomas. The aim of this study was to test this hypothesis in a large population-based cohort study. Women born in Sweden 1958–2000 (N = 2,204,126) were identified and matched with the Medical Birth Register and the Cancer Register. The expected number of meningioma cases and risk ratios were calculated for parous and nulliparous women and compared to the observed number of cases. Compared to parous women, meningiomas were more common among nulliparous (SIR = 1.73; 95% CI 1.52–1.95). The number of meningioma cases detected during pregnancy was lower than the expected (SIR = 0.40; 95% CI 0.20–0.72). Moreover, no increased risk was found in the first-year post-partum (SIR = 1.04; 95% CI 0.74–1.41). Contrary to our hypothesis, there was no increased risk for diagnosing a meningioma during pregnancy or 1-year post-partum. A lower detection rate during pregnancy, may reflect under-utilization of diagnostic procedures, but the actual number of meningiomas was homogenously lower among parous than nulliparous women throughout the study period, indicating that pregnancy is not a risk factor for meningioma.

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.

Recent Advances in Meningioma Immunogenetics

Meningiomas are relatively common, and typically benign intracranial tumors, which in many cases can be cured by surgical resection. However, less prevalent, high grade meningiomas, grow quickly, and recur frequently despite treatment, leading to poor patient outcomes. Across tumor grades, subjective guidelines for histological analysis can preclude accurate diagnosis, and an insufficient understanding of recurrence risk can cloud the choice of optimal treatment. Improved diagnostic and prognostic markers capable of discerning between the 15 heterogeneous WHO recognized meningioma subtypes are necessary to improve disease management and identify new targeted drug treatments. In this review, we show the advances in molecular profiling and immunophenotyping of meningiomas, which may lead to the development of new personalized therapeutic strategies.

Emerging Medical Treatments for Meningioma in the Molecular Era

Meningiomas are the most common type of primary central nervous system tumors. Approximately, 80% of meningiomas are classified by the World Health Organization (WHO) as grade I, and 20% of these tumors are grade II and III, considered high-grade meningiomas (HGMs). Clinical control of HGMs, as well as meningiomas that relapse after surgery, and radiation therapy is difficult, and novel therapeutic approaches are necessary. However, traditional chemotherapies, interferons, hormonal therapies, and other targeted therapies have so far failed to provide clinical benefit. During the last several years, next generation sequencing has dissected the genetic heterogeneity of meningioma and enriched our knowledge about distinct oncogenic pathways driving different subtypes of meningiomas, opening up a door to new personalized targeted therapies. Molecular classification of meningioma allows a new design of clinical trials that assign patients to corresponding targeted agents based on the tumor genetic subtypes. In this review, we will shed light on emerging medical treatments of meningiomas with a particular focus on the new targets identified with genomic sequencing that have led to clinical trials testing novel compounds. Moreover, we present recent development of patient-derived preclinical models that provide platforms for assessing targeted therapies as well as strategies with novel mechanism of action such as oncolytic viruses.

Temozolomide Combined with Radiotherapy in the Treatment of Recurrent Cranial Meningioma Previously Treated with Multiple Surgical Resections and Two Sessions of Radiosurgery: A Case Report and Literature Review

Meningioma is a common primary brain tumor in adults. The treatment approach depends on its grade, size and symptoms. The case reported here was a repeatedly recurring transitional meningioma, previously treated with several surgical procedures and two sessions of cranial radiosurgery. At the time of last relapse, temozolomide was administered alone and combined with external beam radiation therapy. At the last follow-up after 38 months, the disease was stable. In conclusion, in this case of plurirecurrent meningioma, treatment with temozolomide alone and in combination with radiotherapy was feasible and associated with limited morbidity, providing clinical benefit and long local disease control. We discuss the case comparing our approach with other experiences reported in the literature.

Management of Atypical and Anaplastic Meningiomas

Meningiomas are the most prevalent primary tumor of central nervous system origin and, although most neoplasms are benign, a small proportion exemplifies an aggressive profile characterized by high recurrence rates, pleomorphic histology, and overall resistance to standard treatment. Standard initial therapy for malignant meningiomas includes maximal safe surgical resection followed by focal radiation in certain cases. The role for chemotherapy during recurrence of these aggressive meningiomas is less clear. Prognosis is poor and recurrence of malignant meningiomas is high. This article provides an overview of atypical and anaplastic malignant meningiomas, their treatment, and ongoing research for more effective treatments.

Medical Management of Meningiomas: Current Status, Failed Treatments, and Promising Horizons

Meningiomas are benign tumors of the central nervous system, with low recurrence risk for World Health Organization (WHO) grade I lesions but a high risk for WHO grade II and III lesions. Current standard treatments include maximum safe surgical resection when indicated and radiation. Only three systemic therapies alpha-interferon, somatostatin receptor agonists, and vascular endothelial growth factor inhibitors are currently recommended by the National Comprehensive Cancer Network for treatment of recurrent meningioma. This paper aims to review medical approaches in the treatment of meningiomas.

The Role of Mifepristone in Meningiomas Management: A Systematic Review of the Literature

OBJECTIVES

We performed a systematic literature review to analyze the clinical application and the safety of mifepristone, a prominent antiprogesterone agent, in meningioma patients.

MATERIALS AND METHODS

A systematic search was performed through Medline, Cochrane, and clinicaltrials.gov databases from 1960 to 2014. Study Selection. Studies were selected through a PICO approach. Population was meningioma patients, meningioma cells cultures, and animal models. Intervention was mifepristone administration. Control was placebo administration or any other drug tested. Outcomes were clinical and radiological responsiveness, safety profile, and cell growth inhibition.

RESULTS

A total of 7 preclinical and 6 clinical studies and one abstract were included. Encouraging results were found in preclinical studies. Concerning clinical studies, the response rate to mifepristone in terms of radiological regression and symptomatic improvement/stability in patients with inoperable meningioma was low. In meningiomatosis, favorable preliminary results were recorded. The safety profile was good. Limitations were as follows. The tumoral expression of progesterone receptors was not analyzed systematically in every study considered.

CONCLUSIONS

No clear evidence exists to recommend mifepristone in inoperable meningiomas. Preliminary encouraging results were found in diffuse meningiomatosis. Mifepristone is a well-tolerated treatment. Patients' selection and hormonal profile analysis in meningiomas are fundamental for a better understanding of its benefit. Multicenter placebo-controlled trials are required.

Successful treatment of multiple intracranial meningiomas with the antiprogesterone receptor agent mifepristone (RU486)

BACKGROUND

Meningiomas are the most frequent primary brain tumor in adults. Evidence suggests that female sex hormones play a role in the meningioma tumorigenesis. In particular, progesterone, has a receptor (PR) that is highly expressed in the majority of grade I meningiomas. Multiple meningiomas (diffuse meningiomatosis) are less frequent, but have a higher female predominance and a higher PR expression. They are, therefore, attractive candidates for anti-PR therapy.

METHODS

We treated three consecutive women with multiple meningiomas with mifepristone (RU 486). It is a synthetic steroid with high affinity for both progesterone and glucocorticoid receptors.

RESULTS

The treatment was well tolerated, and we observed an important and long-lasting clinical (3/3) and radiological response (2/3) or stabilisation. All the three patients are now stable after five to nine years of treatment.

CONCLUSIONS

These encouraging results strongly support a prospective clinical trial in this preselected population.

Antiglucocorticoid therapy for older adults with anxiety and co-occurring cognitive dysfunction: results from a pilot study with mifepristone

OBJECTIVES

In older adults with anxiety disorders, chronically elevated cortisol may contribute to cognitive impairment and elevated anxiety. We conducted a pilot study with mifepristone, a glucocorticoid receptor antagonist, as a potential treatment for late-life anxiety disorders and co-occurring cognitive dysfunction.

METHODS

Fifteen individuals 60 years and older with an anxiety disorder plus cognitive dysfunction participated in the 12-week study. In the first week, participants were randomly assigned to mifepristone 300 mg daily or placebo. In the subsequent 3 weeks, all participants received mifepristone 300 mg. Mifepristone was then discontinued, and the participants were reassessed 8 weeks later. We examined the following: (1) cognitive changes; (2) worry symptom severity; (3) safety and tolerability; and (4) salivary cortisol before, during, and after mifepristone exposure.

RESULTS

Overall safety, tolerability, and high retention supported the feasibility of this research. Participants with higher baseline cortisol levels (peak cortisol >6.0 ng/ml, n = 5) showed improvements in memory, executive function, and worry severity after 3-4 weeks of mifepristone with persistent memory and worry improvements 8 weeks after mifepristone discontinuation. Individuals with low-to-normal baseline cortisol (n = 8) showed little to no improvement. As expected, cortisol levels rose during mifepristone exposure and returned to pretreatment levels 8 weeks after mifepristone discontinuation. In the first week of treatment, there were no differences between placebo-treated and mifepristone-treated participants.

CONCLUSION

The results of this pilot study warrant further testing of antiglucocorticoid agents in late-life anxiety disorders with co-occurring cognitive dysfunction. Mifepristone is hypothesized to have benefits in patients with evidence of glucocorticoid excess. Directions for further study are discussed.

Novel therapies for meningiomas

Although advances in surgery, radiation therapy and stereotactic radiosurgery have significantly improved the treatment of meningiomas, there remains an important subset of patients who remain refractory to conventional therapy. Treatment with chemotherapeutic agents such as hydroxyurea and alpha-interferon has provided minimal benefit. In this review, the role of newly emerging novel therapies for meningiomas, with a focus on targeted molecular agents, will be discussed.

Intracranial meningiomas in patients with uterine sarcoma treated with long-term megestrol acetate therapy

OBJECTIVE

To report a series of four patients with uterine sarcoma, including one with müllerian adenosarcoma (MA) and three with low-grade endometrial stromal sarcoma (LGESS), who developed intracranial meningiomas while receiving the progesterone agonist megestrol acetate.

METHODS

The hospital records, imaging studies, and pathology slides of four patients who were treated for uterine sarcomas and subsequently developed intracranial meningiomas were reviewed.

RESULTS

All patients underwent surgery for their gynecologic cancers and received maintenance therapy with long-term hormonal suppression with megestrol acetate. Each of the four patients later developed neurologic symptoms secondary to intracranial meningiomas. Three patients had more than one meningioma. Histopathologic examination of all excised tumors showed strong immunoreactivity for progesterone receptors (PRs).

CONCLUSIONS

Patients with uterine sarcoma subtypes LGESS and MA may be predisposed to develop meningiomas, particularly in the setting of long-term treatment with megestrol acetate. Alternatively, preexisting, clinically silent meningiomas in these patients may have progressed to the point of clinical symptoms in the presence of the progesterone agonist megestrol acetate. Without previous imaging studies showing the presence or absence of meningioma before initiation of megestrol acetate treatment, there is no way to draw definitive conclusions regarding this possibility. Clinical and neuroradiologic surveillance for meningiomas should be strongly considered in patients with these uterine sarcoma subtypes, particularly in patients undergoing long-term suppressive therapy with megestrol acetate.

Study of effectiveness of mifepristone for glioma cell line growth suppression

OBJECTIVE

Glioblastoma multiforme is a malignant primary brain tumour with very limited treatment options. Any addition to existing treatment options which can improve prognosis and life expectancy is useful. In our study, we look at the usefulness of anti-progestogen mifepristone in causing growth suppression of glioma cell lines in the laboratory.

METHODS

We cultured five cell lines in the lab and exposed them to mifepristone in different doses for a total of 96 h. Five different doses of mifepristone were used. Progesterone and dexamethasone were also used as growth stimulants. Immunostaining was used to identify progesterone receptors (PRs) in the cell lines.

RESULTS

U257/7 and IN1265 showed statistically significant growth suppression (36% and 11%, P = 0.001 and 0.03 respectively), maximal at 96 h. Growth suppression in U257/7 showed a dose response progression except with the lowest dose which was not explicable. The response of IN1265 was seen only with the highest dose of mifepristone. There was no significant growth stimulation with either dexamethasone or progesterone. None of the cell lines showed any significant positivity for PRs.

CONCLUSION

We were able to produce enough growth suppression of glioma cell lines using mifepristone. This is in keeping with some of the published results in literature. This raises the possibility of using mifepristone in treating GBMs which have very limited treatment options. This, however, needs further work probably on primary glioma cultures first followed by in vivo studies before it can be used in patients.

Update on meningiomas

Although meningiomas are the most common tumor in the central nervous system, their incidence, epidemiology, and clinical outcomes have historically been poorly defined. This has been attributed to their benign course, difficulty obtaining histologic diagnosis, and lack of uniform database registration. Their clinical behavior can range from a silent incidentaloma to a lethal tumor. Projections of an aging population should raise medical awareness of an expectant rise in the incidence of meningiomas. This disease increases with advancing age, has a female predilection, and exposure to ionizing radiation is associated with a higher risk for disease development. There have been minimal advances in treatment, except in radiation therapy. Although no U.S. Food and Drug Administration-approved systemic therapy exists, there are treatment options that include hydroxyurea and sandostatin. Currently, no molecularly targeted therapy has provided clinical benefit, although recurring molecular alterations are present and novel therapies are being investigated.

Phase II study of Gleevec® plus hydroxyurea (HU) in adults with progressive or recurrent meningioma

We prospectively evaluated the efficacy and safety of imatinib plus hydroxyurea in patients with progressive/recurrent meningioma. A total of 21 patients with progressive/recurrent meningioma were enrolled in this dual center, single-arm, phase II trial. All patients received 500 mg of hydroxyurea twice a day. Imatinib was administered at 400 mg/day for patients not on CYP3A enzyme inducing anti-epileptic drugs (EIAEDs) and at 500 mg twice a day for patients on EIAEDs. The primary endpoint was progression-free survival at 6 months (PFS-6) and secondary endpoints were safety, radiographic response rate, and overall survival (OS). Best radiographic response was stable disease and was observed in 14 patients (67%). PFS-6 for all patients, those with grade I tumors (n = 8) and those with grade II or III tumors (n = 13) was 61.9, 87.5 and 46.2%, respectively. Patients with grade II or III tumors had poorer PFS and OS than those with grade I tumors, (P = 0.025 and P = 0.018) respectively. The only grade 3 or greater adverse event occurring in ≥ 10% of patients was anemia (10%). Imatinib plus hydroxyurea is well tolerated among patients with meningioma but has modest anti-tumor activity for this indication.

Brain tumors and hormonal factors: review of the epidemiological literature

BACKGROUND

To date, the etiology of primary tumors of the central nervous system (mainly gliomas and meningiomas) is poorly understood. The role of sex hormones has been suggested, based on clinical, experimental, biological, and epidemiological data.

OBJECTIVE

To review the epidemiological studies on the relation between hormonal factors and the occurrence of glioma and meningioma, in order to identify new research developments.

METHODS

Articles published until September 2010 were selected by considering exogenous and endogenous exposures and specific brain tumors. Standardized information was collected from 20 articles: 15 concerning gliomas and 13 meningiomas.

RESULTS

An increased glioma risk was observed with later menarche and menopause, while a reduced glioma risk was observed with hormone replacement therapy (HRT) and oral contraceptive use, despite duration of use had no effect on risk. Meningioma risk increased after menopause and with HRT use. No clear association was found with pregnancy and breastfeeding.

CONCLUSION

Results are globally concordant with the biologic hypothesis assuming that female sex hormones are protective against glioma and may increase the risk of meningioma. However, new epidemiological studies should be conducted in order to confirm these associations and to refine the role of hormonal factors in brain etiology.

Medical therapies for meningiomas

Meningiomas are the most common primary brain tumor in adults. Although the majority of these tumors can be effectively treated with surgery and radiation therapy, an important subset of patients have inoperable tumors, or develop recurrent disease after surgery and radiotherapy, and require some form of medical therapy. There are increasing numbers of studies evaluating various medical therapies but the results remain disappointing. Chemotherapies and hormonal therapies have been generally ineffective, although somatostatin analogues may have therapeutic potential. There is also increasing interest in targeted molecular therapies. Agents inhibiting platelet derived growth factor receptors and epidermal growth factor receptors have shown little efficacy, but molecular agents inhibiting vascular endothelial growth factor receptors appear to have some promise. As with other tumors, advances in the medical therapies for meningiomas will require improved understanding of the molecular pathogenesis of these tumors, more predictive preclinical models, and efficient mechanisms for conducting clinical trials, given the small population of eligible patients.

The prince and the pauper. A tale of anticancer targeted agents

Cancer rates are set to increase at an alarming rate, from 10 million new cases globally in 2000 to 15 million in 2020. Regarding the pharmacological treatment of cancer, we currently are in the interphase of two treatment eras. The so-called pregenomic therapy which names the traditional cancer drugs, mainly cytotoxic drug types, and post-genomic era-type drugs referring to rationally-based designed. Although there are successful examples of this newer drug discovery approach, most target-specific agents only provide small gains in symptom control and/or survival, whereas others have consistently failed in the clinical testing. There is however, a characteristic shared by these agents: -their high cost-. This is expected as drug discovery and development is generally carried out within the commercial rather than the academic realm. Given the extraordinarily high therapeutic drug discovery-associated costs and risks, it is highly unlikely that any single public-sector research group will see a novel chemical "probe" become a "drug". An alternative drug development strategy is the exploitation of established drugs that have already been approved for treatment of non-cancerous diseases and whose cancer target has already been discovered. This strategy is also denominated drug repositioning, drug repurposing, or indication switch. Although traditionally development of these drugs was unlikely to be pursued by Big Pharma due to their limited commercial value, biopharmaceutical companies attempting to increase productivity at present are pursuing drug repositioning. More and more companies are scanning the existing pharmacopoeia for repositioning candidates, and the number of repositioning success stories is increasing. Here we provide noteworthy examples of known drugs whose potential anticancer activities have been highlighted, to encourage further research on these known drugs as a means to foster their translation into clinical trials utilizing the more limited public-sector resources. If these drug types eventually result in being effective, it follows that they could be much more affordable for patients with cancer; therefore, their contribution in terms of reducing cancer mortality at the global level would be greater.

A phase II study of mifepristone (RU-486) in castration-resistant prostate cancer, with a correlative assessment of androgen-related hormones

OBJECTIVE

To evaluate mifepristone (RU-486) in patients with castration-resistant prostate cancer (CRPC), with a correlative assessment of serum androgens and androgen metabolites

PATIENTS AND METHODS

The androgen receptor (AR) is critical in the development and progression of prostate cancer, but available antiandrogens incompletely abrogate AR signalling. Mifepristone is a potent AR antagonist that functions by competing with androgen, preventing AR coactivator binding and by enhancing binding of AR corepressors. Patients with CRPC were treated with mifepristone 200 mg/day oral until disease progression. Testosterone, dihydrotestosterone (DHT), androstenedione, dihydroepiandrosterone sulphate and the testosterone metabolite 3 alpha-diol G, were measured at baseline and during therapy.

RESULTS

Nineteen patients were enrolled between April and August 2005; they were treated for a median (range) of 85 (31-338) days. The median prostate-specific antigen (PSA) level at enrollment was 22.0 (3.0-937.2) ng/mL. No patient had a PSA response (>50% reduction in PSA). Six patients had stable disease for a median of 5.5 months. After 1 month, adrenal androgens were increased and testosterone and DHT increased by 91% and 80%, respectively, compared to baseline.

CONCLUSION

Mifepristone had limited activity in patients with CRPC, and stimulated a marked increase in adrenal androgens, testosterone and DHT. We hypothesise that inhibition of glucocorticoid receptor by mifepristone resulted in an increase in adrenocorticotropic hormone and subsequent increase in adrenal androgens, and that their conversion by tumour cells to testosterone and DHT probably limited the efficacy of mifepristone. These data emphasize the continued importance of alternative androgen sources in AR signalling in CRPC.

Meningioma

Meningiomas are mostly benign tumours originating from the arachnoid cap cells, represent 13-26% of all intracranial tumours. They are more common in older age and in females. Deletion in NF2 gene and exposure to ionizing radiation are established risk factors, while the role of sex hormones is yet not clarified. Five-year survival for typical meningiomas exceeds 80%, but is poorer (5-year survival <60%) in malignant and atypical meningiomas. Papillary and haemangiopericytic morphology, large tumour size, high mitotic index, absence of progesterone receptors, deletions and loss of heterozygosity are poor prognostic factors. Complete surgical excision is the standard treatment. Radiotherapy is currently used in the clinical practice in atypical, malignant or recurrent meningioma at a total dose of 45-60Gy. However, the role of adjuvant irradiation is still controversial and has to be compared in a randomised prospective setting with a policy of watchful waiting. Radiosurgery has gained more and more importance in the management of meningiomas, especially in meningiomas that cannot be completely resected as for many skull base meningiomas. Medical therapy for patients with recurrent, progressive and symptomatic disease after repeated surgery, radiosurgery and radiotherapy is investigational. Hormonal therapy with progesterone antagonists has shown modest results, while chemotherapy with hydroxyurea appears moderately active.

Patient gender is associated with distinct patterns of chromosomal abnormalities and sex chromosome linked gene-expression profiles in meningiomas

The female predominance of meningiomas has been established, but how this is affected by hormones is still under discussion. We analyzed the characteristics of meningiomas from male (n = 53) and female (n = 111) patients by interphase fluorescence in situ hybridization (iFISH). In addition, in a subgroup of 45 (12 male and 33 female) patients, tumors were hybridized with the Affymetrix U133A chip. We show a higher frequency of larger tumors (p = .01) and intracranial meningiomas (p = .04) together with a higher relapse rate (p = .03) in male than in female patients. Male patients had a higher percentage of del(1p36) (p < .001), while loss of an X chromosome was restricted to tumors from female patients (p = .008). In turn, iFISH studies showed a higher frequency of chromosome losses, other than monosomy 22 alone, in meningiomas from male patients (p = .002), while female patients displayed a higher frequency of chromosome gains (p = .04) or monosomy 22 alone (p = .03) in the ancestral tumor clone. Interestingly, individual chromosomal abnormalities had a distinct impact on the recurrence-free survival rate of male versus female patients. In turn, gene expression showed that eight genes (RPS4Y1, DDX3Y, JARID1D, DDX3X, EIF1AY, XIST, USP9Y, and CYorf15B) had significantly different expression patterns (R(2) > 0.80; p < .05) in tumors from male and female patients. In summary, we show the existence of different patterns of chromosome abnormalities and gene-expression profiles associated with patient gender, which could help to explain the slightly different clinical behavior of these two patient groups.

Hydroxyurea chemotherapy in the treatment of meningiomas

✓ Meningiomas are slow growing, extraaxial tumors that derive from the arachnoidal cap cells of the meninges. Resection remains the main modality of treatment and can be curative in some cases. External-beam radiotherapy and radiosurgery can benefit selected patients. The role of chemotherapy continues to be defined, but should be considered for patients with inoperable or frequently recurring meningiomas. Hydroxyurea, an inhibitor of ribonucleotide reductase, is one of the most active agents and is known to induce apoptosis in meningioma cells in vitro and in mouse xenografts. Results of preliminary clinical studies suggest that hydroxyurea has modest activity against recurrent and inoperable meningiomas, and can induce long term stabilization in some patients. However, the results are conflicting and a few clinical trials did not show positive results. Further clinical trials with larger patient cohorts and longer follow-up periods will be necessary to confirm the activity of hydroxyurea.

Targeted drug therapy for meningiomas

✓ Although advances in surgery, radiation therapy, and stereotactic radiosurgery have significantly improved the treatment of meningiomas, there remains an important subset of patients whose tumors are refractory to conventional therapy. Treatment with traditional chemotherapeutic agents has provided minimal benefit. In this review, the role of targeted molecular therapies for recurrent or progressive meningiomas is discussed.

New prospects for management and treatment of inoperable and recurrent skull base meningiomas

Skull base, including optic nerve, cavernous sinus, clival and foramen magnum tumors represent a major challenge for neurosurgeons and neuro-oncologists. Growth regulatory signaling pathways for these tumors are of increasing interest as potential targets for new chemotherapy. Those differentially activated in various grades of meningiomas are currently being identified as well. This article reviews some recent findings pathways that appear to regulate meningioma growth. Potential targets for novel therapies are also discussed.

Risk of brain tumors associated with exposure to exogenous female sex hormones

The etiology of brain tumors is largely unknown. Prior observations have implicated gender-specific hormones in the pathogenesis of these tumors. In a population-based case-control study, the authors identified all women aged 20-69 years who had been diagnosed with meningioma or glioma during 2000-2002 in four regions of Sweden. Controls were randomly selected from the study base. Detailed information on hormone usage, including use of hormonal contraceptives, hormonal treatment for gynecologic problems, and hormone replacement therapy, was collected from 178 meningioma cases, 115 glioma cases, and 323 controls. Data were analyzed using unconditional logistic regression, adjusting for age, residential area, education, and parity. An increased relative risk of meningioma was found among postmenopausal women for ever use of hormone replacement therapy, with an odds ratio of 1.7 (95% confidence interval: 1.0, 2.8). Women who had used long-acting hormonal contraceptives (subdermal implants, injections, or hormonal intrauterine devices) had an increased risk of meningioma; the odds ratio for at least 10 years of use was 2.7 (95% confidence interval: 0.9, 7.5). Hormone usage was not associated with glioma risk in this study. The findings suggest that the use of female sex steroids may increase the risk of meningioma.

Chronic progesterone antagonist-estradiol therapy suppresses breakthrough bleeding and endometrial proliferation in a menopausal macaque model

BACKGROUND

Clinicians routinely prescribe progestins along with estrogens during menopausal hormone therapy (HT) to block estrogen-dependent endometrial proliferation. Breakthrough bleeding (BTB) can negate the utility of this treatment. Because progestin antagonists also inhibit estrogen-dependent endometrial proliferation in women and macaques, we used a menopausal macaque model to determine whether a potent progestin antagonist (ZK 230 211, Schering AG; ZK) combined with estrogen would provide a novel mode of HT.

METHOD

Ovariectomized rhesus macaques were treated for 5 months with either estradiol (E(2)) alone, E(2) + progesterone (two doses) or E(2) + ZK (0.01, 0.05 or 0.25 mg/kg).

RESULTS

In the E(2) + progesterone groups, progesterone suppressed endometrial proliferation and induced a thick decidualized endometrium. In the E(2) + ZK 230 211 groups, all doses of ZK blocked endometrial proliferation and induced endometrial atrophy. In all ZK-treated groups, the atrophied endometrium contained some dilated glands lined by an inactive, flattened, non-mitotic epithelium. BTB was much lower in the E(2) + ZK groups (17 days of spotting, all groups) than in the E(2) and E(2) + progesterone groups (155 bleeding days, all groups). ZK suppressed E(2) effects in the cervix, but not in the vagina, oviduct or mammary glands. All serum chemistry and lipid profiles were normal.

CONCLUSION

The ability of ZK to block estrogen-dependent endometrial proliferation, induce endometrial atrophy and suppress BTB in a menopausal macaque model indicates that progestin antagonists may provide a novel mode of HT.

Female predominance in meningiomas can not be explained by differences in progesterone, estrogen, or androgen receptor expression

The female predominance in meningioma incidence and association between meningioma and breast cancer suggest that growth of meningiomas is hormone-dependent. There are several discrepancies in literature about the proliferative effect of sex hormones on meningiomas. This study aims to evaluate the hormone receptor status of meningiomas and assess its relation to age, sex, histological grade, recurrence, and proliferation activity. The material was based on consecutive patients operated for meningioma at Tampere University Hospital in 1989-1999. The occurrence of progesterone, estrogen and androgen receptor in patients with primary and recurrent meningiomas was studied immunohistochemically by using specific monoclonal antibodies. Hormonal status was determined in 510 tumor samples. 443 samples were from primary meningiomas and 67 from recurrent tumors. Of the samples, 455 were benign (WHO grade I), 49 atypical (grade II), and 6 malignant (grade III). Of the primary tumor samples, 88% were progesterone receptor positive, 40% were positive for estrogen and 39% for androgen receptors. Grade I meningiomas had significantly higher incidence for estrogen and androgen receptors than higher grade meningiomas. Estrogen positive tumor samples had significantly higher proliferation index than estrogen negative samples. No difference in expression of sex hormone receptors was observed by sexes or age group. Estrogen and androgen receptors may have more influence on the pathogenesis of meningiomas than earlier thought. The higher incidence of meningiomas in women can not be explained by differences of sex hormone receptor expression.

Salvage chemotherapy with CPT-11 for recurrent meningioma

BACKGROUND

A prospective Phase II study of irinotecan (CPT-11) in adult patients with recurrent surgery and radiotherapy-refractory WHO Grade I meningioma.

METHODS

Sixteen patients (5 men; 11 women) ages 48-70 years (median 62.5), with recurrent meningioma were treated. All patients had previously been treated with surgery (complete in 4; partial in 9; biopsy in 3) and involved-field radiotherapy (median dose 54 Gy; 12 following first surgery and 4 following second surgery). Additionally, eight patients underwent re-operation (complete in 2; partial in 6) and eight patients were treated with salvage stereotactic radiosurgery. No patient was treated with prior chemotherapy. CPT-11 was administered intravenously every 3 weeks (350 mg/m2/day in patients on non-enzyme inducing anticonvulsants [NEIAED]; 600 mg/m2/day in patients on enzyme-inducing anticonvulsants [EIAED]) for 9 weeks (operationally defined as a single cycle). Neurological and neuroradiographic evaluation were performed every 10 weeks.

RESULTS

All patients were evaluable. A median of two cycles of CPT-11 (range 1-4) was administered. CPT-11 related-toxicity (> or = grade 3) included diarrhea (6 occurrences, 19% all cycles administered), granulocytopenia (6, 19%), leukopenia (5, 16%), thrombocytopenia (3, 10%) and anemia (3, 10%). Four patients required transfusion (3 RBC and 1 platelet). One patient developed neutropenic fever without bacteriologic confirmation. No treatment-related deaths occurred. No patient demonstrated a neuroradiographic complete or partial response (PR), 13 patients (81%) demonstrated stable disease but disease progressed after 2 cycles of CPT-11, and 3 patients (19%) had progressive disease (PD) following a single cycle of CPT-11. Time to tumor progression ranged from 2.5 to 5.0 months (median 5.0 months). Survival ranged from 4 to months (median 7.5 months).

CONCLUSIONS

The primary objective was to estimate the 6-month progression-free survival (PFS) after study entry. As no patient demonstrated PFS at 6-months, the study was stopped prematurely as specified by study design. Using CPT-11 in this moderately toxic dose schedule failed to demonstrate efficacy in this cohort of adult patients with recurrent surgery and radiotherapy-refractory meningioma.

The use of mifepristone in the treatment of neuropsychiatric disorders

Mifepristone is a potent glucocorticoid and progesterone receptor antagonist. The pathophysiology of a number of neuropsychiatric disorders implicates abnormalities in glucocorticoid function. These include mood disorders such as psychotic major depression and bipolar depression. In addition, cognitive disorders such as Alzheimer's disease might also be partially mediated by abnormalities in the hypothalamic-pituitary-adrenal axis. Preliminary studies suggest that mifepristone might have a role in the treatment of a number of neuropsychiatric disorders.

Management of patients receiving long-term treatment with mifepristone

OBJECTIVE

To determine clinical side effects and biochemical and hematological abnormalities in patients with nonresectable meningioma on long-term mifepristone (RU 486) therapy.

DESIGN

Long-term mifepristone administration in patients with meningioma.

SETTING

Outpatient clinic of a university hospital.

PATIENT(S)

Sixteen women and 9 men aged 22-80 years with nonresectable meningioma.

INTERVENTION(S)

Mifepristone (200 mg daily). One patient received treatment for more than 13 years; six received treatment for 10-12 years; five received treatment for 4-9 years; eight received treatment for 1-4 years; and the remainder received treatment for 4-10 months.

MAIN OUTCOME MEASURE(S)

Evaluation of side effects and of hematological and biochemical abnormalities.

RESULT(S)

Fatigue was observed in 22 of 25 patients. Endometrial hyperplasia occurred in one premenopausal woman and one postmenopausal woman. Another two women had endometrial thickening without hyperplasia. There were no consistent abnormalities in liver or renal function or in any other biochemical or hematological parameters. One subject (on long-term dexamethasone) developed hypoadrenalism, which responded to treatment.

CONCLUSION(S)

Mifepristone can be administered for prolonged periods. Ultrasound should be performed if irregular vaginal bleeding occurs. In asymptomatic women, it should be performed annually. If endometrial thickening is observed, then endometrial biopsy is recommended. Because biochemical hypothyroidism has been reported during long-term mifepristone therapy, thyroid function tests should be performed annually.

Mitogenic Signal Transduction Pathways in Meningiomas: Novel Targets for Meningioma Chemotherapy?

The roles of growth factor receptors and numerous downstream growth regulatory pathways are of increasing interest in neuro-oncology. These pathways have been extensively studied in gliomas but only recently analyzed in meningiomas. This article reviews current research on the growth factor receptor-Ras-Raf-1-MEK-1-MAPK, PI3K-Akt/PKB, PLC-gamma1-PKC, phospholipase A2-cyclooxygenase, and TGF-beta receptor-Smad pathways that appear to regulate meningioma growth and inhibit apoptosis. Sites along these receptor/kinase cascades that might be targeted by novel therapies are also discussed.

[Present and potential uses of mifepristone in gynecology, obstetrics and other medical specialties]

Mifepristone, a derivative of norethindrone, a first generation synthetic progestative, has a very potent antiprogestative activity and to a lesser degree antiandrogenic and antiglucocorticoid activities. This action makes it potentially useful in the treatment of multiple hormone dependent diseases in obstetrics-gynecology as well as in a variety of medical specialties such as neurology, ophthalmology, and oncology. Nevertheless, the label of abortive pill has incited numerous ethical and political debates concerning the permission to market this drug, and this has contributed to the delay in the assessment of the potential indications of mifepristone. Largely under-utilized in practice despite its increasing theoretical benefit, clinical studies should now de conducted. Thus, based on an international review of literature during the last ten years, we have shed light on the present and potential indications of mifepristone in medical practice.

The prognostic value of progesterone receptor status in meningiomas

BACKGROUND

Meningiomas are known to recur frequently, and their longterm management remains controversial. Previous studies indicate that progesterone and its receptors can play a role in the recurrence of meningiomas, but the correlation between the presence of these receptors and patients' outcome is unclear.

AIM

To conduct a retrospective analysis to investigate the prognostic relevance of progesterone receptor (PR) expression in meningiomas.

METHODS

Five hundred and eighty eight meningiomas operated on over a period of 10 years were examined immunohistochemically to determine the PR status using monoclonal antibodies. Several factors including recurrence (mean follow up of 65 month), sex, tumour tissue consistency, location, vascularity, and en plaque appearance were analysed.

RESULTS

PR status showed comparable values for men and women. World Health Organisation (WHO) grade II and III tumours had significantly fewer receptors than benign meningiomas. There was no significant correlation between PR status and recurrence rates in WHO grade I totally removed meningiomas. However, a combination of PR status and proliferation indices was shown to predict recurrence reliably.

CONCLUSIONS

Together with routine histological evaluation, PR status can help to describe the biological behaviour of meningiomas. Only a combination of clinical and biological features can describe the behaviour of meningiomas, predict their recurrence, and help to devise more effective follow up strategies.

Meningioma: Current treatment options and future directions

Benign meningiomas can be observed if not symptomatic or growing. When treatment is indicated, the options are surgery, radiosurgery, fractionated radiation therapy, or a combination of these modalities. Except in certain cases, such as large tumors that require debulking for relief of symptoms, we do not recommend the routine use of combination therapy. Intracranial meningiomas have usually been treated with surgical resection with an expected durable local control of 80% to 90% when a gross total resection (GTR) is obtained. Patients who have inoperable disease, refuse surgery, undergo less than a GTR, or who have aggressive histology should instead be considered candidates for radiation therapy or radiosurgery. While benign meningiomas can be successfully treated definitively or postoperatively with either fractionated radiation therapy or single fraction radiosurgery, atypical or malignant lesions are best treated with fractionated radiation therapy with conventional dosimetric margins. The role of systemic therapy is not yet defined, but multiple agents are being investigated in early phase trials for patients with recurrent or progressive disease after standard therapy has failed.

Progesterone-receptor index in meningiomas: correlation with clinico-pathological parameters and review of the literature

For recurrent and untreatable meningiomas alternative therapies, such as anti-progesterone treatment, have been sought. However, the few clinical studies have not determined progesterone receptor (PgR) expression in most cases, and studies correlating quantitative PgR expression (PgR index) with clinico-pathological variables are scarce. The aim of our study was to assess the PgR indices in a consecutive series of meningiomas and correlate these values with clinico-pathological parameters. We analyzed immunohistochemically 82 consecutive meningioma specimens (73 primary and nine recurrent tumors) for PgR and Ki-67 antigen (MIB-1). The male/female ratio was 1:1.7, and median age at the time of surgery was 57 years (range 29-77 years). The series comprised 55 grade I (subtyped as 36 meningothelial, seven fibrous, nine transitional, two psammomatous, and one angiomatous), 23 grade II, and one grade III meningiomas. Nuclear immunostaining for PgR was positive in 56 meningioma specimens (71%). PgR index was 21.4+/-2.8% (mean +/- SE; range 0-79%). Significantly higher expression was found in male patients in the age group <50 years than in those > or = 60 years and in grade I meningothelial meningiomas than in fibrous and transitional subtypes. There was a trend to lower PgR indices in non-benign meningiomas. Cell proliferation rate (MIB-1 index) was 4.4 +/- 0.4% (mean +/- SE; range 0.3-15.4%). Significantly higher MIB-1 indices were found in male than female patients,in recurrent than primary and in grade II than grade I meningiomas. We observed a trend to higher PgR indices in meningiomas with MIB-1 index <5%. In sum, the highest PgR index in our series was observed in patients under the age of 50 years with WHO grade I meningiomas of the meningothelial subtype and low cell proliferation indices. If hormonal therapy has a direct action on the PgR, these patients should respond best to anti-progesterone treatment. We conclude that PgR index is variable in meningioma, depending on clinical parameters and histopathological features. Stratification of anti-progesterone therapy trials on the basis of PgR index should be considered.

Meningiomas: Updating Basic Science, Management, and Outcome

BACKGROUND

Meningiomas are biologically complex and clinically and surgically challenging. These features, combined with the rewarding potential for cure, make them of great interest to neurologists, neurosurgeons, and neuroscientists alike.

REVIEW SUMMARY

Initially, we review the clinical context of meningiomas, particularly recent changes in histopathological classification, diagnosis, and neuroimaging. Secondly, the underlying basic science as it has evolved over the last decades is summarized. The status of areas recently of intense interest, such as steroid hormone receptors and oncogenic viruses is described. Additionally, emerging areas of great promise, such as cytogenetics and molecular biology are presented. Lastly, we describe recent advances in management. In particular, skull-base surgery, image-guided surgery, and advances in radiotherapy are emphasized. The possible impact of basic research on management and outcome is also outlined.

CONCLUSIONS

Although usually benign and amenable to cure, meningiomas still present significant diagnostic and treatment challenges. Advances in basic science, surgery, and adjuvant therapy are widening the potential for safe, effective, evidence-based management leading to even better outcomes

Multiple meningiomas arising during long-term therapy with the progesterone agonist megesterol acetate

In this report the authors describe a woman with low-grade endometrial stromal sarcoma who was treated with total abdominal hysterectomy and bilateral salpingo-oophorectomy. After receiving megestrol acetate continuously for 19 years for chronic hormone suppression, she began to experience progressive dementia. Magnetic resonance imaging revealed 11 separate intracranial meningiomas of various sizes. The largest lesions were treated with staged angiographically guided embolization and excision. Despite discontinuation of megestrol acetate, the remaining smaller lesions grew slightly in size, requiring further treatment with a combination of excision and gamma knife stereotactic surgery. All of the excised tumors showed positive staining for progesterone receptors on immunohistochemical examination. Prolonged therapy with megestrol acetate could promote the growth of benign intracranial meningiomas in some patients.