Maintenance therapy with everolimus for subependymal giant cell astrocytoma in patients with tuberous sclerosis (the EMINENTS study)

Radiotherapy for subependymal giant cell astrocytoma: time to challenge a historical ban? A case report and review of the literature

BACKGROUND

Subependymal giant cell astrocytoma is a benign brain tumor that occurs in patients with tuberous sclerosis complex. Surgical removal is the traditional treatment, and expert opinion is strongly against the use of radiotherapy. Recently, success has been reported with the mTor inhibitor everolimus in reducing tumor volume, but regrowth has been observed after dose reduction or cessation.

CASE REPORT

We present the case of a 40-year-old Asian female patient treated successfully for growing bilateral subependymal giant cell astrocytoma with fractionated stereotactic radiotherapy before everolimus became available. After a follow-up of 8 years, everolimus was administered for renal angiomyolipoma and the patient was followed up until 13 years after radiotherapy. Successive magnetic resonance imaging demonstrated an 80% volume reduction after radiotherapy that increased to 90% with everolimus. A review of the literature was done leveraging Medline via PubMed, and we assembled a database of 1298 article references and 780 full-text articles in search of evidence for contraindicating radiotherapy in subependymal giant cell astrocytoma. Varying results of single-fraction radiosurgery were described in a total of 13 cases. Only in two published cases was the radiation dose of fractionated radiotherapy mentioned. One single publication mentions an induced secondary brain tumor 8 years after whole-brain radiotherapy.

CONCLUSION

There is no evidence of contraindication and exclusion of fractionated radiotherapy in treating subependymal giant cell astrocytoma. Our experience demonstrates that subependymal giant cell astrocytoma, as other benign intracranial tumors, responds slowly but progressively to radiotherapy and suggests that fractionated stereotactic radiotherapy holds promise to consolidate responses obtained with mTor inhibitors avoiding regrowth after cessation.

Benign Glioma

Benign glioma broadly refers to a heterogeneous group of slow-growing glial tumors with low proliferative rates and a more indolent clinical course. These tumors may also be described as "low-grade" glioma (LGG) and are classified as WHO grade I or II lesions according to the Classification of Tumors of the Central Nervous System (CNS) (Louis et al. in Acta Neuropathol 114:97-109, 2007). Advances in molecular genetics have improved understanding of glioma tumorigenesis, leading to the identification of common mutation profiles with significant treatment and prognostic implications. The most recent WHO 2016 classification system has introduced several notable changes in the way that gliomas are diagnosed, with a new emphasis on molecular features as key factors in differentiation (Wesseling and Capper in Neuropathol Appl Neurobiol 44:139-150, 2018). Benign gliomas have a predilection for younger patients and are among the most frequently diagnosed tumors in children and young adults (Ostrom et al. in Neuro Oncol 22:iv1-iv96, 2020). These tumors can be separated into two clinically distinct subgroups. The first group is of focal, well-circumscribed lesions that notably are not associated with an increased risk of malignant transformation. Primarily diagnosed in pediatric patients, these WHO grade I tumors may be cured with surgical resection alone (Sturm et al. in J Clin Oncol 35:2370-2377, 2017). Recurrence rates are low, and the prognosis for these patients is excellent (Ostrom et al. in Neuro Oncol 22:iv1-iv96, 2020). Diffuse gliomas are WHO grade II lesions with a more infiltrative pattern of growth and high propensity for recurrence. These tumors are primarily diagnosed in young adult patients, and classically present with seizures (Pallud et al. Brain 137:449-462, 2014). The term "benign" is a misnomer in many cases, as the natural history of these tumors is with malignant transformation and recurrence as grade III or grade IV tumors (Jooma et al. in J Neurosurg 14:356-363, 2019). For all LGG, surgery with maximal safe resection is the treatment of choice for both primary and recurrent tumors. The goal of surgery should be for gross total resection (GTR), as complete tumor removal is associated with higher rates of tumor control and seizure freedom. Chemotherapy and radiation therapy (RT), while not typically a component of first-line treatment in most cases, may be employed as adjunctive therapy in high-risk or recurrent tumors and in some select cases. The prognosis of benign gliomas varies widely; non-infiltrative tumor subtypes generally have an excellent prognosis, while diffusely infiltrative tumors, although slow-growing, are eventually fatal (Sturm et al. in J Clin Oncol 35:2370-2377, 2017). This chapter reviews the shared and unique individual features of the benign glioma including diffuse glioma, pilocytic astrocytoma and pilomyxoid astrocytoma (PMA), subependymal giant cell astrocytoma (SEGA), pleomorphic xanthoastrocytoma (PXA), subependymoma (SE), angiocentric glioma (AG), and chordoid glioma (CG). Also discussed is ganglioglioma (GG), a mixed neuronal-glial tumor that represents a notable diagnosis in the differential for other LGG (Wesseling and Capper 2018). Ependymomas of the brain and spinal cord, including major histologic subtypes, are discussed in other chapters.

Research Progress on the Regulation Mechanism of Key Signal Pathways Affecting the Prognosis of Glioma

As is known to all, glioma, a global difficult problem, has a high malignant degree, high recurrence rate and poor prognosis. We analyzed and summarized signal pathway of the Hippo/YAP, PI3K/AKT/mTOR, miRNA, WNT/β-catenin, Notch, Hedgehog, TGF-β, TCS/mTORC1 signal pathway, JAK/STAT signal pathway, MAPK signaling pathway, the relationship between BBB and signal pathways and the mechanism of key enzymes in glioma. It is concluded that Yap1 inhibitor may become an effective target for the treatment of glioma in the near future through efforts of generation after generation. Inhibiting PI3K/Akt/mTOR, Shh, Wnt/β-Catenin, and HIF-1α can reduce the migration ability and drug resistance of tumor cells to improve the prognosis of glioma. The analysis shows that Notch1 and Sox2 have a positive feedback regulation mechanism, and Notch4 predicts the malignant degree of glioma. In this way, notch cannot only be treated for glioma stem cells in clinic, but also be used as an evaluation index to evaluate the prognosis, and provide an exploratory attempt for the direction of glioma treatment. MiRNA plays an important role in diagnosis, and in the treatment of glioma, VPS25, KCNQ1OT1, KB-1460A1.5, and CKAP4 are promising prognostic indicators and a potential therapeutic targets for glioma, meanwhile, Rheb is also a potent activator of Signaling cross-talk etc. It is believed that these studies will help us to have a deeper understanding of glioma, so that we will find new and better treatment schemes to gradually conquer the problem of glioma.

Research Progress on the Regulation Mechanism of Key Signal Pathways Affecting the Prognosis of Glioma

As is known to all, glioma, a global difficult problem, has a high malignant degree, high recurrence rate and poor prognosis. We analyzed and summarized signal pathway of the Hippo/YAP, PI3K/AKT/mTOR, miRNA, WNT/β-catenin, Notch, Hedgehog, TGF-β, TCS/mTORC1 signal pathway, JAK/STAT signal pathway, MAPK signaling pathway, the relationship between BBB and signal pathways and the mechanism of key enzymes in glioma. It is concluded that Yap1 inhibitor may become an effective target for the treatment of glioma in the near future through efforts of generation after generation. Inhibiting PI3K/Akt/mTOR, Shh, Wnt/β-Catenin, and HIF-1α can reduce the migration ability and drug resistance of tumor cells to improve the prognosis of glioma. The analysis shows that Notch1 and Sox2 have a positive feedback regulation mechanism, and Notch4 predicts the malignant degree of glioma. In this way, notch cannot only be treated for glioma stem cells in clinic, but also be used as an evaluation index to evaluate the prognosis, and provide an exploratory attempt for the direction of glioma treatment. MiRNA plays an important role in diagnosis, and in the treatment of glioma, VPS25, KCNQ1OT1, KB-1460A1.5, and CKAP4 are promising prognostic indicators and a potential therapeutic targets for glioma, meanwhile, Rheb is also a potent activator of Signaling cross-talk etc. It is believed that these studies will help us to have a deeper understanding of glioma, so that we will find new and better treatment schemes to gradually conquer the problem of glioma.

Low-Dose Everolimus Maintenance Therapy for Renal Angiomyolipoma Associated With Tuberous Sclerosis Complex

Objective: To assess the safety and efficacy of low-dose everolimus maintenance therapy for tuberous sclerosis complex-related renal angiomyolipoma (TSC-RAML) patients that had previously undergone standard-dose treatment for a minimum of 6 months.

Materials and Methods: In total, 24 patients with a definitive TSC diagnosis were enrolled from April 2018 – April 2019 at Xiangya Hospital, Central South University. All patients underwent low-dose everolimus maintenance therapy following standard-dose everolimus induction therapy for a minimum of 6 months. Patients additionally underwent TSC1/TSC2 genetic testing, And they were followed-up at 3, 6, 12, 18, and 24 months. The Response Evaluation Criteria in Solid Tumors (RECIST, version 1.1) criteria were used to monitor patient RAML responses, while adverse events (AEs) were assessed as per the National Cancer Institute Common Terminology Criteria for Adverse Events (CTCAE, version 4.0). P < 0.05 was the significance level for all analyses, which were performed using SPSS 19.0.

Results: TSC1/TSC2 gene mutations were present in all 24 patients, all of whom achieved a significant reduction in TSC-RAML volume within the initial 6-month induction therapy period, and exhibited volume stabilization during the low-dose maintenance therapy treatment period without any instances of TSC-RAML regrowth. Adverse events (AEs) were significantly less severe and less frequent over the course of maintenance therapy relative to standard therapy.

Conclusions: Low-dose everolimus maintenance therapy represents an effective approach to achieving TSC-RAML control following a minimum of 6 months of full-dose induction therapy, and may be associated with decreases in everolimus-related AE frequency and severity.

The Effect of Everolimus on Subependymal Giant Cell Astrocytoma (SEGA) in Children with Tuberous Sclerosis Complex

Objective

Subependymal Giant Cell Astrocytomas (SEGAs) are slow-growing glioneuronal tumors typically found around the ventricles of the brain, particularly near the foramen of Monro in 15%-20% of patients with tuberous sclerosis complex (TSC). Surgical resection is the standard treatment for these symptomatic tumors. The mTOR inhibitor everolimus can be regarded as an alternative treatment for SEGAs due to the complications of surgery. The present study primarily aimed to specify the effect of everolimus on SEGA volume change before and after treatment. The secondary objective was to determine the effect of this drug on renal angiomyolipoma (AML), skin lesions, and seizures in TSC patients.

Materials & Methods

This pre- and post-treatment clinical trial was performed on 14 children (eight females and six males with a mean age of 10 years) previously diagnosed with TSC based on the diagnostic criteria. The subjects received oral everolimus at a dose of 3 mg/m² for at least six months.

Results

Half of the patients had more than 30% of volume loss in SEGA, and in 28.5% of them, a ≥ 50% reduction in SEGA volume was observed (P=0.01). Moreover, 92.9% of the patients had a ≥ 50% decrease in the frequency of seizures (P=0.000). The response rate in AML and skin lesions was 14.2% and 50%, respectively.

Conclusion

Everolimus significantly reduced the seizure frequency and SEGA volume in the subjects; hence, it can be used as a potential alternative treatment for symptomatic SEGA in TSC patients.

Updated International Tuberous Sclerosis Complex Diagnostic Criteria and Surveillance and Management Recommendations

BACKGROUND

Tuberous sclerosis complex (TSC) is an autosomal dominant genetic disease affecting multiple body systems with wide variability in presentation. In 2013, Pediatric Neurology published articles outlining updated diagnostic criteria and recommendations for surveillance and management of disease manifestations. Advances in knowledge and approvals of new therapies necessitated a revision of those criteria and recommendations.

METHODS

Chairs and working group cochairs from the 2012 International TSC Consensus Group were invited to meet face-to-face over two days at the 2018 World TSC Conference on July 25 and 26 in Dallas, TX, USA. Before the meeting, working group cochairs worked with group members via e-mail and telephone to (1) review TSC literature since the 2013 publication, (2) confirm or amend prior recommendations, and (3) provide new recommendations as required.

RESULTS

Only two changes were made to clinical diagnostic criteria reported in 2013: "multiple cortical tubers and/or radial migration lines" replaced the more general term "cortical dysplasias," and sclerotic bone lesions were reinstated as a minor criterion. Genetic diagnostic criteria were reaffirmed, including highlighting recent findings that some individuals with TSC are genetically mosaic for variants in TSC1 or TSC2. Changes to surveillance and management criteria largely reflected increased emphasis on early screening for electroencephalographic abnormalities, enhanced surveillance and management of TSC-associated neuropsychiatric disorders, and new medication approvals.

CONCLUSIONS

Updated TSC diagnostic criteria and surveillance and management recommendations presented here should provide an improved framework for optimal care of those living with TSC and their families.

Clinical, genetic and quality-of-life study of a cohort of adult patients with tuberous sclerosis

Background and objective

Tuberous sclerosis (TS) is a condition whose manifestations in childhood have been extensively described, but whose presentation in adults is less well known. This study describes the clinical and genetic characteristics, therapeutic management and quality of life of a cohort of adult patients with TS. A comparative study of the characteristics of patients diagnosed in childhood and adulthood is also carried out.

Material and methods

This observational, retrospective, cross-sectional study included a large cohort of adult patients (≥ 16 years old) followed for 5 years in a specific rare diseases unit.

Results

Fifty-seven patients with a diagnosis of tuberous sclerosis were included, more than 50% of whom were diagnosed as adults. The mean age of the patients was 42 years (20–86). The central nervous system was the main area affected (97%), followed by the skin (80.7%) and kidneys (73%). The most frequent genetic alteration was a mutation in the TSC2 gene (47.7%). Among patients diagnosed in adulthood, there was less neurological involvement, with less frequency of epileptic seizures (30.8% vs 60.79% of patients diagnosed in childhood) and astrocytomas (3.8% vs 53.6%), less intellectual disability (11.5% vs 71.4%) and less expressiveness of the condition. 42% of patients were treated with mTOR pathway inhibitors, and presence of an angiomyolipoma was the main indication. In a quality-of-life analysis, the means of the summary indices were below the scores of the average Spanish population: (47.42 (SD ± 9.82) on the physical health scale, 45.61 (SD ± 7.99) on the mental health scale) versus 50 (SD ± 10) for the general population.

Conclusions

Up to 50% of adult patients with TS were diagnosed in adulthood, and the condition is less severe with less frequent epileptic seizures and intellectual disability. 42% require treatment with mTOR inhibitors, in most cases due to the presence of AMLs. The quality of life of adult patients with TS is diminished compared to the general population.

Maintenance Therapy With Everolimus for Subependymal Giant Cell Astrocytoma in Patients With Tuberous Sclerosis - Final Results From the EMINENTS Study

The aim of this EMINENTS prospective, single-center, open-label, single-arm study was to evaluate the cumulative efficacy and safety of reduced doses of everolimus (maintenance therapy) in patients with tuberous sclerosis and subependymal giant cell astrocytoma (SEGA).

Methods: The trial included 15 patients who had undergone at least 12 months of treatment with a standard everolimus dose. The dose of everolimus was reduced to three times a week, with a daily dose as in standard regimen. Data of 14 patients were analyzed. SEGA volume (SV) was evaluated at study entry and subsequent time points by an experienced radiologist. Adverse events (AEs) noted during maintenance therapy were compared to the AEs of standard dose period.

Results: Patients were followed over a mean duration 58.37 months (95%CI: 45.95–70.78). The differences in SEGA volume between subsequent time points (0, 3, 6,12, 18, 24, 36, 48, and 60 months) were not statistically significant (p = 0.16). At the end of the study, 7 out of 10 patients had stable SEGA volume. No clinical symptoms of progression were observed in any patients. No patient or tumor-related risk factors of progression were identified. Regarding AEs, infections (stomatitis, bronchitis, diarrhea) and laboratory abnormalities (neutropenia, anemia, hyperglycemia) occurred less frequently during maintenance therapy compared to the standard dose regimen.

Conclusions: Final results from EMINENTS study confirm that maintenance therapy with everolimus might represent a rational therapeutic option for patients TSC and SEGA after effective full dose treatment. It could be an option for patients who experienced everolimus-related AEs, instead of discontinuation of therapy. Careful evaluation of possible progression, especially concerning first six months of maintenance therapy should be advised.

Clinical Trial Registration:www.drks.de, identifier DRKS00005584.

Uncommon low-grade brain tumors

The 2016 World Health Organization (WHO) classification of primary central nervous system (CNS) tumors includes numerous uncommon (representing ≤1% of tumors) low-grade (grades I-II) brain neoplasms with varying clinical behaviors and outcomes. Generally, gross tumor or maximal safe resection is the primary treatment. Adjuvant treatments, though their exact role is unknown, may be considered individually based on pathological subtypes and a proper assessment of risks and benefits. Targetable mutations such as BRAF (proto-oncogene B-Raf), TRAIL (tumor necrosis factor apoptosis inducing ligand), and PDGFR (platelet derived growth factor receptor) have promising roles in future management.

Improving Diagnostic and Therapeutic Outcomes in Pediatric Brain Tumors

Pediatric brain tumors are the primary cause of cancer-related death during childhood. Unfortunately, the number of primary and metastatic brain tumors is steadily increasing while the mortality rates for many central nervous system (CNS) lesions have remained stagnant. Molecularly defined tumor classes have been added to the most recent 2016 World Health Organization (WHO) Classification System of Central Nervous System Brain Tumors, driving potential new treatments and identifying targets to improve survival for these patients. Focusing on the genetic mutations most commonly seen in the pediatric CNS tumor population provides the ability to better define tumors based on shared molecular characteristics. Consequently, there is the potential for greater efficacy in targeted therapy to treat these identified genetic aberrations. Understanding the growing importance of molecular diagnosis in pediatric CNS tumors is vital to successfully using novel targeted therapies and improving patient outcomes.

Efficacy and Safety of Mammalian Target of Rapamycin Inhibitor Use-Long-term Follow-up of First Tuberous Sclerosis Complex Patient Treated De Novo With Sirolimus After Kidney Transplantation: A Case Report

Mammalian target of rapamycin inhibitors (mTORI) are increasingly used in the treatment of tuberous sclerosis complex (TSC) and as immunosuppressants after organ transplantation. In TSC patients, mTORI are the treatment of choice after kidney transplantation. It is still under debate if benefits from long-term mTORI use will not be limited by side effects.

MATERIALS AND METHODS

We report long-term follow-up data of the first TSC patient after kidney transplantation treated with sirolimus de novo. In 2005, a female patient was transplanted with a kidney graft after bilateral nephrectomy due to angiomyolipoma. Initial immunosuppressive treatment consisted of antithymocyte globulin, methylprednisolone, tacrolimus, and, due to TSC diagnosis, sirolimus. Creatinine level at discharge was 1.2 mg/dL.

RESULTS

Long-term mTORI use resulted in skin lesion regression (angiofibromas, "confetti" skin lesions, shagreen patch) and disease stabilization in brain, abdominal, and chest magnetic resonance imaging/computed tomography scans. Pulmonary function tests showed improvement in restriction and slow deterioration in obstruction and diffusion parameters. Sirolimus related adverse reactions were hyperlipidemia and hypertriglyceridemia and respiratory and urinary tract infections. No gastrointestinal or hematologic symptoms occurred. Sirolimus concentrations ranged between 1.7 and 8.2 ng/mL (mean 4.01 ± 2.09 ng/mL). Since 2009 proteinuria and slow increase in creatinine level have been observed. No biopsy was performed to establish etiology and potential association with mTORI. In 2017 creatinine level was 2.2 mg/dL.

CONCLUSION

The case of the patient confirms clinical effectiveness and acceptable safety of long-term mTORI treatment. Long-term mTORI use requires meticulous patient observation to optimize dosage, achieve immunosuppressive effect, and improve TSC manifestations with minimal side effects.

Tuberous sclerosis complex-associated CNS abnormalities depend on hyperactivation of mTORC1 and Akt

Tuberous sclerosis complex (TSC) is a dominantly inherited disease caused by hyperactivation of the mTORC1 pathway and characterized by the development of hamartomas and benign tumors, including in the brain. Among the neurological manifestations associated with TSC, the tumor progression of static subependymal nodules (SENs) into subependymal giant cell astrocytomas (SEGAs) is one of the major causes of morbidity and shortened life expectancy. To date, mouse modeling has failed in reproducing these 2 lesions. Here we report that simultaneous hyperactivation of mTORC1 and Akt pathways by codeletion of Tsc1 and Pten, selectively in postnatal neural stem cells (pNSCs), is required for the formation of bona fide SENs and SEGAs. Notably, both lesions closely recapitulate the pathognomonic morphological and molecular features of the corresponding human abnormalities. The establishment of long-term expanding pNSC lines from mouse SENs and SEGAs made possible the identification of mTORC2 as one of the mediators conferring tumorigenic potential to SEGA pNSCs. Notably, in spite of concurrent Akt hyperactivation in mouse brain lesions, single mTOR inhibition by rapamycin was sufficient to strongly impair mouse SEGA growth. This study provides evidence that, concomitant with mTORC1 hyperactivation, sustained activation of Akt and mTORC2 in pNSCs is a mandatory step for the induction of SENs and SEGAs, and, at the same time, makes available an unprecedented NSC-based in vivo/in vitro model to be exploited for identifying actionable targets in TSC.

What are the true volumes of SEGA tumors? Reliability of planimetric and popular semi-automated image segmentation methods

OBJECTIVE

To evaluate the reliability of the standard planimetric methodology of volumetric analysis and three different open-source semi-automated approaches of brain tumor segmentation.

MATERIALS AND METHODS

The volumes of subependymal giant cell astrocytomas (SEGA) examined by 30 MRI studies of 10 patients from a previous everolimus-related trial (EMINENTS study) were estimated using four methods: planimetric method (modified MacDonald ellipsoid method), ITK-Snap (pixel clustering, geodesic active contours, region competition methods), 3D Slicer (level-set thresholding), and NIRFast (k-means clustering, Markov random fields). The methods were compared, and a trial simulation was performed to determine how the choice of approach could influence the final decision about progression or response.

RESULTS

Intraclass correlation coefficient was high (0.95; 95% CI 0.91-0.98). The planimetric method always overestimated the size of the tumor, while virtually no mean difference was found between ITK-Snap and 3D Slicer (P = 0.99). NIRFast underestimated the volume and presented a proportional bias. During the trial simulation, a moderate level of agreement between all the methods (kappa 0.57-0.71, P < 0.002) was noted.

CONCLUSION

Semi-automated segmentation can ease oncological follow-up but the moderate level of agreement between segmentation methods suggests that the reference standard volumetric method for SEGA tumors should be revised and chosen carefully, as the selection of volumetry tool may influence the conclusion about tumor progression or response.

Influence of cyclosporine and everolimus on the main mycophenolate mofetil pharmacokinetic parameters: Cross-sectional study

The objective of the present study was to assess the effect of cyclosporine (CsA) on the pharmacokinetic parameters of mycophenolic acid (MPA), an active mycophenolate mofetil (MMF) metabolite, and to compare with the effect of everolimus (EVR).Anonymized medical records of 404 kidney recipients were reviewed. The main MPA pharmacokinetic parameters (AUC(0-12) and Cmax) were evaluated.The patients treated with a higher mean dose of CsA displayed higher MPA AUC(0-12) exposure in the low-dose MMF group (1000 mg/day) (40.50 ± 10.97 vs 28.08 ± 11.03 h mg/L; rs = 0.497, P < 0.05), medium-dose MMF group (2000 mg/day) (43.00 ± 6.27 vs 28.85 ± 11.08 h mg/L; rs = 0.437, P < 0.01), and high-dose MMF group (3000 mg/day) (56.75 ± 16.78 vs 36.20 ± 3.70 h mg/L; rs = 0.608, P < 0.05).A positive correlation was also observed between the mean CsA dose and the MPA Cmax in the low-dose MMF group (Cmax 22.83 ± 10.82 vs 12.08 ± 5.59 mg/L; rs = 0.507, P < 0.05) and in the medium-dose MMF group (22.77 ± 8.86 vs 13.00 ± 6.82 mg/L; rs = 0.414, P < 0.01).The comparative analysis between 2 treatment arms (MMF + CsA and MMF + EVR) showed that MPA AUC(0-12) exposure was by 43% higher in the patients treated with a medium dose of MMF and EVR than in the patients treated with a medium dose of MMF and CsA.The data of the present study suggest a possible CsA versus EVR influence on MMF pharmacokinetics. Study results show that CsA has an impact on the main MPA pharmacokinetic parameters (AUC(0-12) and Cmax) in a CsA dose-related manner, while EVR mildly influence or does not affect MPA pharmacokinetic parameters. Low-dose CsA (lower than 180 mg/day) reduces MPA AUC(0-12) exposure under the therapeutic window and may lead to ineffective therapy, while a high-dose CsA (>240 mg/day) is related to greater than 10 mg/L MPA Cmax and increases the likelihood of adverse events.