EP08.02 THE CLINICAL OUTCOME OF BEVACIZUMAB FOR RECURRENT HIGH-GRADE GLIOMAS: A POLISH SINGLE CENTER EXPERIENCE

Abstract BACKGROUND In spite of advancements in therapy in recent years, high-grade gliomas are still invariably recurrent and incurable. At recurrence a multimodality treatment is being offered including neurosurgery, chemotherapy and reirradiation even though no clear standards of care are available. Some patients however deplete all the conventional treatment methods and have progression of the disease still having an overall performance status (PS) eligible for further treatment. In Poland reimbursement of bevacizumab given its cost, efficacy and potential toxicities is highly conditional and is perceived as salvage therapy. This study aims to analyse the clinical outcome of the use of bevacizumab in such highly pretreated patients. MATERIAL AND METHODS A single-center retrospective analysis of patients receiving bevacizumab for recurrent high-grade gliomas since 2019 to 2025 was performed. Patients demographics, tumor characteristics, previous treatment, adverse effects and dates of clinical progression and death were collected. Overall survival (OS) and progression-free survival (PFS) were used as clinical outcomes and estimates. Radiological response was assessed using modified Response Assessment in Neuro-Oncology criteria. RESULTS The study included 15 patients, of these 9 were female (60%) and 6 were male (40%). The histo-pathological diagnosis were: Astrocytoma (40%), Glioblastoma (46,7%) and Oligodendroglioma (13,3%). Median age at the start of immunotherapy was 43 years (34-68). Median time for all patients from first diagnosis to the start of bevacizumab was 34 months (10-152 [CI 95%=29,3-63,2 months]). The group of GBM patients had the shortest time to the start of bevacizumab - median 26,7 months (10-58, [CI 95%=10,7-36,6 months]). Three patients (20%) experienced G3 adverse effects. One had pulmonary embolism and had to discontinue the treatment permanently. The other two discontinued temporarily due to uncontrolled hypertension. During treatment 80% of patients were receiving GKS and in 42% of those patients the daily dose of GKS could be reduced and in 25% discontinued. PFS was 7,4 months (CI 95%=-1,27-16,07). During the observation period 13 out of 15 patients progressed. Of those 62% of patients had radiological and 46% of patients experienced clinical progression. Two patients are stable both clinically and radiologically. OS was 11,1 months (CI 95%=1,28-20,85). No statistically significant difference in PFS or OS was found between the subgroups of patients according to age, histopathology and gender. CONCLUSION Bevacizumab as salvage treatment is a valuable option for patients with good PS, if there is no other therapeutic option. Further research with a larger number of patients is needed to determine which subgroup(s) of patients benefit the most from bevacizumab therapy upon recurrence.