Novel therapies for meningiomas

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.

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.

Peptide receptor radionuclide therapy in patients with inoperable meningiomas: our experience and review of the literature

OBJECTIVE

Few studies describe peptide receptor radionuclide therapy (PRRT) using (90)Y- or (177)Lu-labeled peptides in patients with recurrent meningiomas. No clinical data about (111)In-Pentetreotide in such patients are available. We report on (111)In-Pentetreotide therapy in patients with inoperable meningiomas and review the literature about PRRT of meningiomas.

METHODS

We reviewed clinical records of 8 patients with meningioma/meningiomatosis showing high (111)In-Pentetreotide uptake on pretherapy scintigraphy who were treated with at least one cycle of (111)In-Pentetreotide. In 2 patients, a cocktail of (111)In-Pentetreotide and beta-emitting radiolabeled peptides had been administered.

RESULTS

No patient experienced acute toxicity, neurological or renal function impairment. Mild transient bone marrow toxicity was observed in 4 patients. Objective partial response was observed in 2 patients, stable disease in 5 and disease progression in one. There were no statistically significant correlations between objective response and patient age, tumor WHO grade, baseline Karnofsky performance score, (111)In-Pentetreotide tumoral uptake grade, tumor/nontumor ratio, disease state at baseline, and cumulative dose.

CONCLUSIONS

In consideration of its efficacy and the lack of significant toxicity, PRRT of meningiomas using (111)In-Pentetreotide could be proposed even nowadays when the use of (177)Lu- or (90)Y-labeled peptides seems unsafe, namely in patients with renal impairment/toxicity.

A hypoxia-inducible factor (HIF)-3α splicing variant, HIF-3α4 impairs angiogenesis in hypervascular malignant meningiomas with epigenetically silenced HIF-3α4

Hypoxia inducible factor is a dominant regulator of adaptive cellular responses to hypoxia and controls the expression of a large number of genes regulating angiogenesis as well as metabolism, cell survival, apoptosis, and other cellular functions in an oxygen level-dependent manner. When a neoplasm is able to induce angiogenesis, tumor progression occurs more rapidly because of the nutrients provided by the neovasculature. Meningioma is one of the most hypervascular brain tumors, making anti-angiogenic therapy an attractive novel therapy for these tumors. HIF-3α has been conventionally regarded as a dominant-negative regulator of HIF-1α, and although alternative HIF-3α splicing variants are extensively reported, their specific functions have not yet been determined. In this study, we found that the transcription of HIF-3α4 was silenced by the promoter DNA methylation in meningiomas, and inducible HIF-3α4 impaired angiogenesis, proliferation, and metabolism/oxidation in hypervascular meningiomas. Thus, HIF-3α4 could be a potential molecular target in meningiomas.

Evolution and future of skull base surgery: the paradigm of skull base meningiomas

BACKGROUND

Skull base meningiomas represent the paradigm for the evolution of skull base surgery within the past 50 years into a distinct neurosurgical subspecialty.

METHODS

From 2005 to 2011, 117 patients with cranial base meningiomas underwent surgical resection. Extent of resection, histologic grade, complications, functional status, and recurrence-free and overall survival data are presented.

RESULTS

The summary rate of gross total resection was 53.0%. The surgical complication and mortality rates were 17.9% and 0.9%, respectively. Five-year recurrence-free survival was 88.0% for grade I meningiomas. A total of 90.3% of patients had a Karnofsky performance score ≥ 80 at last follow-up.

CONCLUSIONS

A large contemporary series of skull base meningiomas is presented. In addition, the evolution of surgical approaches to skull base meningiomas is reviewed, together with the current issues regarding radiation therapy, management of cavernous sinus tumor, oncologic management of atypical and malignant subtypes, molecular genetics, and future therapeutic options.

Molecular biology of unreresectable meningiomas: implications for new treatments and review of the literature

Even though meningiomas are most often benign tumors, they can be locally invasive and can develop in locations that prevent surgical treatment. The molecular and biologic factors underlying meningioma development are only now beginning to be understood. Genetic factors such as mutations in the neurofibromatosis-2 gene and in chromosomes 1, 9, and 10 play important roles in meningioma development and may be responsible for atypical tumors in some cases. Cellular factors such as telomerase activation and tyrosine kinase receptor mutations may also play an important role. Finally, autocrine and paracrine factors including epidermal growth factor receptor, platelet-derived growth factor-1, and fibroblast growth factor have been implicated in the development of some tumors. Although the relationship between the various factors implicated in tumor development is unknown, understanding these factors will be critical in the treatment of malignant or surgically inaccessible tumors.

Hydroxyurea for recurrent surgery and radiation refractory meningioma: a retrospective case series

Hydroxyurea (HU), an orally administered chemotherapy, has become the de facto standard therapeutic agent in patients with surgically and radiation refractory meningiomas based on a limited literature. A retrospective case series of 60 patients with recurrent WHO grade 1 meningioma treated with HU following progression after surgery and radiotherapy was conducted with primary study objective progression free survival (PFS) at 6- and 12-months. Sixty patients (45 women; 15 men: median age 61.5 years, range 26-88) with recurrent meningioma were treated with HU (1000 mg/m(2)/day orally divided twice per day; one cycle operationally defined as 4-weeks of daily HU). All patients had progressed radiographically after prior therapy with surgery (60/60) and radiotherapy (external beam radiotherapy 60/60; stereotactic radiotherapy 53/60). No patient received prior chemotherapy or targeted therapy before instituting HU. Patients received 1-12 cycles (median 2.0) of HU with modest toxicity (10% grade 3 + anemia or fatigue). There were no radiographic responses, 35% of patients had stable disease and 65% manifested progressive disease. Duration of stable disease ranged from 3 to 12 months (median 4.0 months). The overall PFS was 10% (median PFS 2.0 months). The majority of patients (80%) following progression on HU were subsequently treated on an investigational trial. In this retrospective case series, HU though generally well tolerated and convenient, appeared to have very limited activity which raises questions of what constitutes effective salvage therapy and indicates an unmet need for alternative treatments for recurrent meningiomas.

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.

Anaplastic meningioma in an adolescent: a report of a rare case and brief review of literature

OBJECTIVE

Anaplastic meningioma is an uncommon neoplasm in childhood and adolescence. Due to the rarity, treatment options for anaplastic meningioma in this age group are not clearly outlined.

CASE

A 15-year-old boy presented with a left forehead swelling with a history of a left frontal tumor. Radiological investigations revealed a dura-based tumor with a large extracranial and a smaller intracranial component. Craniotomy with near-total excision of the tumor was performed. Histopathological examination of the tumor showed features of an anaplastic meningioma. The patient is currently receiving radiotherapy and chemotherapy. However, he has developed scalp swellings while on radiotherapy.

CONCLUSION

Anaplastic meningioma is extremely rare in children. Extensive sampling is required to recognize the meningothelial nature of the tumor and immunohistochemistry helps in making an accurate diagnosis in such cases. Therapeutic interventions in such cases need to be closely monitored due to the aggressive behavior of this tumor.

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.