Reduced-intensity Bevacizumab in Progressive Glioblastoma Multiforme (GBM) is Associated with Similar Overall Survival Versus Standard-Dosing

Background: Bevacizumab (BEV) has demonstrated activity in glioblastoma multiforme (GBM), particularly with regard to symptom control, however overall survival (OS) benefits have not been clearly defined in prospective randomised phase III trials. Most studies have used 10mg/Kg q 2wks as standard although some experts suggest a less intensive dose schedule might offer similar benefits at a lower cost and therefore better value. Methods: We retrospectively analysed data from the prospective database of the national neuro-oncology centre in Ireland. All patients who received BEV at the time of progression for histologically-proven de novo GBM from 2010 to 2016 were included. At our institution there is variable practice between Neuro-Oncologists in terms of BEV dosing schedule - standard BEV dosing (10mg/kg q 2wks or 15mg/kg q 3wks) vs. reduced-intensity BEV (5mg/kg q 2wks or 7.5mg/kg q 3wks). Using the Kaplan-Meier method, we assessed OS in the entire cohort and by BEV dosing schedule. Results: In total, 118 patients received BEV for progressive GBM. Median OS was 5.6 months for the entire population (range: 0.5-42 months) and OS was 45%, 18% and 2% at 6-, 12- and 24-months, respectively. Patient characteristics by BEV dosing schedule were similar (Table). Median OS was similar in the reduced intensity BEV group (N = 49) at 5.5 months and the standard-dose group (N = 69) at 5.6 months, p=0.55. Quality of life analyses are ongoing.Table349PStandard Dose BEVReduced Intensity BEVN = 69N = 49P-ValueGenderN (%)N (%)Male45 (65%)32 (65%)0.99Female24 (35%)17 (35%)AGE< 45 years10 (14.5%)8 (16%)0.9245-65 years42 (60.9%)28 (57%)> 65 years17 (24.6%)13 (27%)MGMTKnown (50/69)Known (36/49)Methylated20 (40%)17 (47%)0.50Unmethylated30 (60%)19 (53%)Time from Diagnosis to BEV start< 12 months36 (52%)24 (49%)12-18 Months16 (23%)12 (24%)0.94> 18 months17 (25%)13 (27%)Median Overall Survival post BEV5.6 Months5.5 Months0.55 Open table in a new tab Conclusions: In this large heterogeneous cohort of patients, OS was similar in patients who received standard or reduced intensity BEV for treatment of progressive GBM. Given the cost of BEV, these results have important implications for value in cancer care. Legal entity responsible for the study: Cancer Clinical Trials Unit (CCTU), Beaumont Hospital, Dublin, Ireland Funding: None Disclosure: All authors have declared no conflicts of interest.