P17.32 * EFFICACY AND TOLERABILITY OF BEVACIZUMAB MONOTHERAPY IN PATIENTS WITH PREVIOUSLY TREATED RECURRENT GLIOBLASTOMA MULTIFORME (GBM)

Abstract

INTRODUCTION: Glioblastoma Multiforme (GBM) represents the most common and malignant form of brain tumor. GBMs are highly vascularized and their cells frequently express the vascular endothelial growth factor (VEGF) receptor. VEGF has a key role in stimulating angiogenesis and enhancing intratumoral vascular permeability. Bevacizumab is a humanized monoclonal antibody which inhibits VEGF and tumor cell growth. Data from the literature show that this drug has a different toxicity profile, pattern of response, and relapse rate in comparison with alchilant agents. PATIENTS AND METHODS: The aim of this study was to evaluate the efficacy and tolerability of Bevacizumab in patients with GBM progressed after prior treatments (STUPP and FTM protocols) and with adequate bone marrow, renal, and hepatic function and Eastern Cooperative Oncology Group Performance Status (ECOG PS) 0-2. The drug was administered as monotherapy every 14 days as an intravenous infusion at the dose of 10 mg/kg until recurrence and/or clinical-radiological progression. Brain magnetic resonance imaging (MRI) scans were performed every 60 days and treatment response was defined according to the McDonald criteria. Toxicity was assessed using the NCI CTCAE (National Cancer Institute Common Terminology Criteria for Adverse Events) version 3.0. RESULTS: From October 2009 to March 2014, we analyzed 15 patients, 8 males (53.3%) and 7 females (46.7%), with a median age of 54.8 years (range 36-70, 4 were over 65 years old); nine (60%) and six (40%) patients had an ECOG PS of 1 and 2, respectively. The median number of cycles administered was 14.3 (range 2-62). Median progression-free survival (PFS) was 130 days (average PFS was 201.8 days). Six patients showed a survival benefit of 12, 12, 10, 8, 17 and 31 months, a partial response and a stable disease were observed in the last three of them, respectively. Disease control rate (DCR) was 53.3%. Bevacizumab was generally well tolerated. Particularly, hematological toxicity, commonly of grade 1, was observed as leucopenia in 40% of cases, while the most common non-hematological side effects were grade 1 increase of gamma glutamyl transpeptidase (GGT) levels (33.3%), fatigue (20%), and proteinuria (20%). CONCLUSIONS: Although our limited sample size does not permit definitive conclusions, Bevacizumab monotherapy appears to be a safe and effective treatment option for recurrent GBM, with a good clinical-radiological response and an increased PFS in most patients.