A rare hematological adverse event induced by bevacizumab: severe thrombocytopenia

Bevacizumab, a monoclonal antibody to vascular endothelial growth factor-A, is approved for the treatment of various malignancies, and its hematological toxicities are considered infrequent.

A colorectal cancer patient receiving chemotherapy (5-fluorouracil and oxaliplatin) plus bevacizumab developed acute, severe thrombocytopenia. We postulated that this thrombocytopenia could be directly triggered by bevacizumab.

A man with stage IV colorectal cancer and synchronous liver metastasis had received 10 cycles of FOLFOX plus bevacizumab (5 mg/kg) without significant hematological toxicity. Due to thrombocytopenia, oxaliplatin was withdrawn after cycle 11. On cycle 12, shortly after bevacizumab infusion and before 5-fluorouracil infusion, the patient developed fever, lower limbs purpura, grade 1 proctorrhagia, and epistaxis. Platelets had decreased from 105,000/mm(3) to 3000/mm(3) within 1 hour after bevacizumab infusion. Flow cytometry identified platelet-associated immunoglobulins. Despite 2 apheresis-derived platelet transfusions, oral corticotherapy, and gamma globulin infusions, thrombocytopenia persisted, but was finally successfully treated with a peptibody thrombopoietin mimetic, which was introduced 28 days after the last bevacizumab infusion.

Clinicians should keep in mind that bevacizumab can induce acute and potentially severe immune-mediated thrombocytopenia.