Labib, Milisia

Abstract BACKGROUND Bevacizumab, an anti-vascular endothelial growth factor (VEGF) monoclonal antibody, has emerged as a treatment for radiation necrosis. Doses ranging from 2.5 mg/kg to 15 mg/kg have been utilized however the optimal dosing remains inadequately studied. METHODS Retrospective review of adult patients with central nervous system tumors or brain metastasis treated with bevacizumab from 6/29/2021 to 7/31/2024. Patients were divided into those who received bevacizumab 7.5 mg/kg every 21 days and those who received bevacizumab 10 mg/kg every 21 days. The primary outcome was radiographic response as assessed by a blinded neuro-oncologist. Secondary outcomes included clinical response as documented in clinical notes, major adverse events including hemorrhage and thromboembolic events and re-dosing for recurrence of radiation necrosis beyond the 4 initially planned doses. RESULTS 104 patients were included (median age 59.3 years, 55% male); 53 patients in the 7.5 mg/kg group and 51 patients in the 10 mg/kg group. In the 7.5 mg/kg group, 1 patient had a complete response (CR), 16 patients had a partial response (PR), 32 patients had stable disease (SD), 3 patients had progression of disease, and 1 patient did not have repeat imaging. Of the 51 patients in the 10 mg/kg group, 3 patients had a CR, 10 patients had a PR, 27 patients had SD, 5 patients had progression of disease, and 6 patients did not have repeat imaging. There was no statistically significant difference in radiographic response between the two dosing groups (p = 0.42). Clinical response rates were higher in the 7.5 mg/kg group (65.2% vs 37.8%, p = 0.013). Major adverse events and need for re-dosing for radiation necrosis recurrence were comparable. CONCLUSION Bevacizumab 7.5 mg/kg was equally as efficacious as 10 mg/kg in terms of radiographic response and may offer a better clinical response for patients with radiation necrosis.