Exceptionally rapid recurrence of malignant meningioma: case report

Anaplastic meningioma represents less than 5% of all meningiomas. It is a neoplasm with a poor prognosis due to aggressiveness and a high rate of recurrence. Patients could remain asymptomatic but clinical characteristics of mass effect are the most common presentation. Although diagnosis is made with histological study, this method is difficult to define, with inter-observer variability. When possible, surgical resection is the primary management. We discuss a case of an adult female patient with tonic-clonic seizures and weakness attributed to an anaplastic meningioma in the occipital lobe. The patient was treated with a parietal craniotomy with complete resection. One month later the patient suffered a recurrence of the tumor with the need for further intervention with incomplete resection. Due to extent of the damage the patient deceased two weeks later.

CTIM-31. A PHASE II, OPEN-LABEL, SINGLE ARM TRIAL OF PEMBROLIZUMAB FOR REFRACTORY ATYPICAL AND ANAPLASTIC MENINGIOMA AND HEMANGIOPERICYTOMA

BACKGROUND Grade II and III meningiomas are invasive tumors which tend to recur following initial treatment and are associated with shorter survival (relative to grade I). Hemangiopericytoma (HPC) is a dural based tumor that originates in the pericytes. Treatment options for these tumors include surgical resection and radiation. There are no defined standard treatments after failure these modalities, and effective systemic treatments are lacking. This trial concept was developed following previous reports of high PD-L1 levels in anaplastic meningioma. We currently report our initial experience with pembrolizumab for refractory atypical/anaplastic meningioma (RAM) and HPC patients. METHODS This is a single arm, single institute, phase 2 trial. Inclusion criteria included patients with RAM or HPC whose all previous lines of treatment were exhausted. All patients were treated with pembrolizumab (200mg every 3 weeks) until disease progression. Primary endpoint was 6- and 12-months progression free survival (PFS). The study was planned for 25 patients and we report here preliminary results. RESULTS Through February 2021, 12 patients were enrolled to this study (two with HPC, 10 with RAM). After a median follow up of 18.5 months, the 6 and 12 months PFS were 25% and 16.7% respectively, with a median PFS of 2.75 months. Two patients had a partial response while all others progressed, making the overall response rate 16.7%. One of the responders had HPC and has been stable for 30 months, while the second had atypical meningioma and was stable for 13 months. Median survival has not been reached yet; 1 year survival rate was 82.5%. Grade 3 toxicities included hyperglycemia, elevated liver enzymes and fatigue, with no grade 4 or 5 toxicities. CONCLUSIONS Pembrolizumab induced a low response rate for RAM and HPC. However, a subset of patients might benefit from this treatment with a prolonged response period.

A phase II, open-label, single-arm trial of pembrolizumab for refractory atypical and anaplastic meningioma and hemangiopericytoma.

2064 Background: Grade II and III meningiomas are invasive tumors which tend to recur following initial treatment and are associated with shorter survival (relative to grade I). Hemangiopericytoma (HPC) is a dural based tumor that originates in the pericytes in the walls of capillaries. Treatment options for these tumors include surgical resection and radiation. There are no defined standard treatments after failure of these modalities, and efficient systemic treatments are lacking. This trial concept was formed following previous reports of high PD-L1 levels in anaplastic meningioma. We currently report our initial experience with pembrolizumab for refractory atypical/anaplastic meningioma (RAM) and HPC patients. Methods: This is a single arm, single institute, phase 2 trial. Inclusion criteria included patients with RAM or HPC whose all previous lines of treatment were exhausted. All patients were treated with pembrolizumab (200mg every 3 weeks) until disease progression. Primary endpoint was 6- and 12-months progression free survival (PFS). The study was planned for 25 patients and we report here preliminary results. Results: Through February 2021, 12 patients were enrolled to this study (two with HPC, 10 with RAM). After a median follow up of 18.5 months, the 6 and 12 months PFS were 25% and 16.7% respectively, with a median PFS of 2.75 months. Two patients had a partial response while all others progressed, making the overall response rate 16.7%. One of the responders had HPC and has been stable for 30 months, while the second had atypical meningioma and was stable for 13 months. Median survival has not been yet reached; 1 year survival rate was 82.5%. Grade 3 toxicities included hyperglycemia, elevated liver enzymes and fatigue (that did not cause treatment discontinuation), with no grade 4 or 5 toxicities. PD-L1, mutation burden, MSI and other genomic analyses are still pending. Conclusions: Pembrolizumab induced a low response rate for RAM and HPC. However, a subset of patients might benefit from this treatment with a prolonged response period. To define this subpopulation further molecular studies are needed. Clinical trial information: NCT03016091.