QLTI-22. Comparison of biosimilar bevacizumab-bvzr to reference bevacizumab in the management of malignant glioma

BACKGROUND Bevacizumab, an anti-VEGF monoclonal antibody, has become a mainstay in the management of malignant gliomas. Multiple bevacizumab biosimilars have been approved since initial FDA approval of the reference agent and have seen widespread use due to reduced cost. However, real-world data evaluating comparability between reference and biosimilar agents have remained limited. METHODS We performed a retrospective analysis of patients treated with reference bevacizumab (Avastin) versus those receiving bevacizumab-bvzr, a widely used biosimilar agent (Zirabev) for the management of malignant glioma at our institution between 2019 and 2022. RESULTS A total of 161 patients were included in our final analysis; 97 received reference drug (Avastin) while 64 received the biosimilar agent (Zirabev). Demographics and baseline clinical characteristics between the two groups were similar. We performed survival analysis with post-progression survival (PPS) to ensure against lead-time bias. PPS was similar between the Avastin (median PPS 496 days) and Zirabev (median PPS 513 days) groups on univariate analysis (p=0.7654). Similarly, on multivariate Cox regression, there were no differences in PPS when comparing Avastin and Zirabev (HR 1.0673, p=0.6986). MGMT promoter methylation (HR 0.5709, p=0.0238), age at cancer diagnosis (HR 1.0356, p=0.0009), total dose of bevacizumab received (HR 0.9975, p=0.0087) and treatment with anticoagulation (HR 1.8086, p=0.0372) were significantly associated with PPS. Rates of therapy-related adverse effects were also similar between those receiving the reference drug and biosimilar agent (OR 0.9043, p=0.7824). However, concomitant treatment with antiplatelet therapy (OR 3.1447, p=0.0150) or anticoagulant therapy (OR 4.9069, p=0.0010) were significantly associated with increased risk for adverse effects. CONCLUSIONS Bevacizumab-bvzr demonstrated similar clinical efficacy and safety profile compared to reference bevacizumab in our institutional cohort. Concomitant treatment with antiplatelet therapy (OR 3.1447, p=0.0150) or anticoagulation (OR 4.9069, p=0.0010) were significantly associated with increased risk for adverse effects.