Safety of bevacizumab in patients with malignant gliomas: a systematic review

Angiogenesis has recently become a major target for the development of new antineoplastic drugs. The most serious adverse events linked to angiogenesis inhibitors are venous or arterial thromboembolism and haemorrhage. Thus, there is need to define with more certainty the impact of these new drugs in terms of adverse effects in neurological patients. The aim of the study is to assess the risk of venous thromboembolism (VTE) and bleeding in patients with malignant gliomas treated with bevacizumab with or without concomitant anticoagulant therapy. A review of published literature was performed in Medline, from which 476 records were identified. A total of 27 full-text articles, including retrospective analyses, retrospective reviews, and open label trials, were assessed for eligibility. The investigated drugs included bevacizumab alone, bevacizumab plus chemotherapy with/without concomitant radiation therapy; only two articles dealt with bevacizumab in association with anticoagulant treatment. A total of 2,208 patients with malignant gliomas, were identified and included in the analysis. From data it appears that patients receiving bevacizumab had a major risk of developing VTE that increased when bevacizumab is associated with radio-chemotherapy (4.27 vs 7.46 %). Regarding bleeding, data showed that patients treated with anticoagulant had a significantly increased risk of severe central nervous system (CNS) bleeding compared to patients not receiving anticoagulant therapy (0.6 vs 8.2 %). The use of bevacizumab combined with chemo-radiotherapy seems to be associated with a higher risk for VTE compared to patients receiving antiangiogenic therapy alone. The associated use of anticoagulants and bevacizumab far increases the risk of developing CNS and non-CNS bleeding higher than grade 3, compared to patients receiving bevacizumab alone.