Safety of Systemic Bevacizumab (Avastin®) Therapy for Neovascular Age–Related Macular Degeneration

Abstract

Abstract: : Purpose: The anti–VEGF humanized monoclonal antibody known as bevacizumab (Avastin®, Genentech Inc.) is approved for the treatment of patients with metastatic colorectal cancer. Several adverse events have been reported following the continuous use of bevacizumab therapy in patients with metastatic cancer. A recent FDA letter warned of an increased risk of potentially fatal thromboembolic events in patients with advanced metastatic colorectal cancer receiving concomitant chemotherapy and continuous bevacizumab therapy. Other adverse events include hypertension, proteinuria, and gastrointestinal bleeding. We prospectively evaluated the safety of non–continuous systemic bevacizumab therapy in neovascular AMD patients. Methods: This open–label, uncontrolled clinical study enrolled AMD patients with subfoveal CNV, a central retinal thickness of at least 300 microns, and visual acuity from 20/40 to 20/400. Major exclusion criteria included uncontrolled hypertension, history of a thromboembolic event, and coagulation abnormalities. At baseline and every 3 months, patients underwent a physical examination by an internist and testing which included an electrocardiogram, complete blood count, chemistry panel, coagulation studies, and urinalysis. Enrolled patients received 2 or 3 infusions of bevacizumab (5mg/kg) at 2 week intervals. Patients were examined every week for the first 6 weeks, every 2 weeks for the next 6 weeks, and every 4 weeks thereafter. Blood pressure was measured at least three separate times at each visit. Medical management of blood pressure was performed by an internist. Results: Of the 15 patients enrolled in the study, 9 patients were followed for at least 3 months. There were no serious systemic adverse events identified. By 6 weeks, the only significant systemic side–effect identified was a mild elevation of 12mm Hg in the median (p=0.026) and mean (p=0.035) systolic blood pressure measurements, and this elevation was controlled by changing or initiating anti–hypertensive medication. By 12 weeks, the elevation of systolic blood pressure was no longer significant (p=0.51). Conclusions: Non–continuous bevacizumab therapy appeared to be well tolerated. A mild, short–term elevation of systolic blood pressure was the only adverse event identified. Additional follow–up is ongoing to determine the long–term safety profile of non–continuous bevacizumab therapy.

Keywords: choroid: neovascularization • age-related macular degeneration • clinical (human) or epidemiologic studies: treatment/prevention assessment/controlled