The failure of hormonal and cytotoxic chemotherapy in the treatment of recurrent meningioma and increasing understanding of potential molecular targets in meningioma has resulted in multiple studies utilizing single-agent targeted therapy directed at biologically relevant signaling pathways, such as somatostatin (Sandostatin(®) LAR, SOM230c), PDGF (imatinib), EGF (erlotinib) and VEGF (sunitinib and vatalanib)1).
Andrae et al analysed the effects of sunitinib in two benign (BenMen-1, HBL52) and two malignant (IOMM-Lee, KT21MG) human meningioma cell lines and found that DNA synthesis was significantly (p ≤ 0.001) inhibited following 1, 2 or 5 μM sunitinib, with IC(50) values between 2 and 5 μM in all cell lines. This effect was associated with a G(2)M-arrest at 10 μM for BenMen-1, HBL52 and IOMM-Lee, and 20 μM in KT21MG cells. Nuclear bisbenzimide staining revealed chromatin condensation following treatment with sunitinib concentrations of 10 μM or higher. Corresponding, cell viability assays showed a significant (p ≤ 0.001) short term decrease of viable cells (24h) only for high sunitinib concentrations with IC(50)-values between 10 and 20 μM. However, pre-irradiated meningioma cells (5 Gy) showed a sensitivity shift towards IC(50)-values around 5 μM sunitinib. We also found that 5 μM strongly reduced meningioma cell migration in vitro. Western blot analyses showed abolished platelet derived growth factor receptor (PDGFR)-autophosphorylation after sunitinib. Interestingly, the drug also inhibited the autophosphorylation of the receptor tyrosine kinase fms-like tyrosine kinase 3 (Flt3) in a dose-dependent manner. Taken together, the present data show that micromolar sunitinib has strong cytostatic and anti-migratory effects on human meningioma cells 2).
Potential activity of VEGF (vascular endothelial growth factor) inhibitors such as sunitinib, vatalanib, and bevacizumab is suggested in small non-controlled studies and requires validation in randomized trials 3) 4) 5) 6) 7) 8).
A clinical trial of sunitinib for treatment of recurrent World health organization grade 2 meningioma and World health organization grade 3 meningioma suggested potential efficacy in this population, but only 2 patients exhibited significant radiographic response with tumor volume reduction.
Raheja et al illustrate another such case and discuss a complication related to this dramatic tumor volume reduction in aggressive skull base meningiomas. The authors describe the case of a 39-year-old woman who had undergone repeat surgical interventions and courses of radiotherapy over the previous 11 years for recurrent cranial and spinal meningiomas. Despite 4 operations over the course of 4 years on her right petroclival meningioma with cavernous sinus and jugular fossa extensions, she had progressive neurological deficits and tumor recurrences. The specimen histology progressed from WHO Grade I initially to Grade II at the time of the third recurrence. The lesion was then irradiated 3 times using stereotactic radiosurgery for further recurrences. More recently, the tumor size increased rapidly on imaging, in association with progressive neurological symptoms arising from brainstem compression and vasogenic edema. Institution of sunitinib therapy yielded a dramatic radiographic response, with marked reduction in the tumor volume and reduction of brainstem vasogenic edema within a few weeks of initiation of treatment. The significant radiographic response of tumor in the clival region was also associated with CSF rhinorrhea from a dural breach created by resolution of the invasive skull base meningioma, which necessitated withholding the sunitinib medication. To address the leak, the authors undertook surgical exploration and transsphenoidal packing using an autologous fat graft and a vascularized pedicled nasoseptal flap. The patient has done well during follow-up of 3 months after packing, with no evidence of recurrent CSF leak, and the medication was subsequently restarted. Prior clinical data and the dramatic radiographic response in this patient suggest that sunitinib holds promising therapeutic potential in carefully selected patients with recurrent atypical meningiomas where conventional strategies have been exhausted. There is a potential risk of associated CSF rhinorrhea, especially in more invasive skull base lesions showing dramatic radiographic response 10).
Thirteen patients with temozolomide-refractory recurrent anaplastic glioma or low-grade glioma were treated with sunitinib malate in combination with lomustine. The most frequent grade 3 and 4 adverse events were fatigue, thrombocytopenia, neutropenia and lymphopenia. The best objective tumor response by Response Assessment in Neuro-Oncology (RANO) criteria was one complete response, one unconfirmed partial response and three cases of stable disease. The median progression-free survival was 1.8 months (95% confidence interval=1.0-2.7 months) with 6-month progression-free survival of 15% (95% confidence interval=0-35%). The median overall survival was 6.7 months (95% confidence interval=0.7-12 months). The investigated combination regimen of sunitinib and lomustine is well-tolerated but insufficiently active to warrant further investigation in an unselected population of patients with temozolomide-refractory recurrent anaplastic and low-grade glioma 11).
A prospective, multicenter, investigator-initiated single-arm phase II trial. The primary cohort enrolled patients with surgery and radiation-refractory recurrent World Health Organization (WHO) grades II-III meningioma. An exploratory cohort enrolled patients with WHO grade I meningioma, hemangiopericytoma, or hemangioblastoma. Sunitinib was administered at 50 mg/d for days 1-28 of every 42-day cycle. The primary endpoint was the rate of 6-month progression-free survival (PFS6), with secondary endpoints of radiographic response rate, safety, PFS, and overall survival. Exploratory objectives include analysis of tumoral molecular markers and MR perfusion imaging.
Thirty-six patients with high-grade meningioma (30 atypical and 6 anaplastic) were enrolled. Patients were heavily pretreated (median number of 5 recurrences, range 2-10). PFS6 rate was 42%, meeting the primary endpoint. Median PFS was 5.2 months (95% CI: 2.8-8.3 mo), and median overall survival was 24.6 months (95% CI: 16.5-38.4 mo). Thirteen patients enrolled in the exploratory cohort. Overall toxicity included 1 grade 5 intratumoral hemorrhage, 2 grade 3 and 1 grade 4 CNS/intratumoral hemorrhages, 1 grade 3 and 1 grade 4 thrombotic microangiopathy, and 1 grade 3 gastrointestinal perforation. Expression of VEGFR2 predicted PFS of a median of 1.4 months in VEGFR2-negative patients versus 6.4 months in VEGFR2-positive patients (P = .005).
Sunitinib is active in recurrent atypical/malignant meningioma patients. A randomized trial should be performed. TRIAL REGISTRATION: ClinicalTrials.gov NCT01125046 12).