Progressive bevacizumab-associated renal thrombotic microangiopathy

Vascular endothelial growth factor (VEGF) is integral to the integrity of the glomerular filtration barrier. Bevacizumab is a humanized monoclonal antibody directed against VEGF with expanding clinical applications for metastatic solid tumours. We describe a case of a 61-year-old female with ovarian cancer and baseline chronic kidney disease who received three doses of bevacizumab and subsequently developed progressive renal clearance dysfunction and nephrotic range proteinuria. A renal biopsy was performed 4 months after drug discontinuation and was consistent with TMA. At baseline, prior to bevacizumab exposure, her estimated glomerular filtration rate (eGFR) was 44 mL/min/1.73 m(2) and she had no proteinuria. At the completion of therapy, eGFR was 27 mL/min/1.73 m(2) with 1+ proteinuria on urinalysis. Her renal failure and proteinuria continued to progress 5 months after discontinuation of bevacizumab therapy, at which time eGFR was 11 mL/min/1.73 m(2) and proteinuria was 5.5 g/24 h. Non-remitting TMA after bevacizumab therapy in patients with pre-existing chronic kidney disease has not been previously reported. Further studies are needed to assess the safety of this drug in patients with chronic kidney disease.