EVALUATION OF IN VITRO EFFECTS OF BEVACIZUMAB (AVASTIN) ON RETINAL PIGMENT EPITHELIAL, NEUROSENSORY RETINAL, AND MICROVASCULAR ENDOTHELIAL CELLS SAURABH LUTHRA, MD,* RAJA NARAYANAN, MD,* L. EDUARDO A. MARQUES, MD,* MARILYN CHWA, MS,* DAE W. KIM, BS,* JOYCE DONG,* GAIL M. SEIGEL, PHD,† ANEESH NEEKHRA, MD,* ANA L. GRAMAJO, MD,* DONALD J. BROWN, PHD,* M. CRISTINA KENNEY, MD, PHD,* BARUCH D. KUPPERMANN, MD, PHD* Purpose: To evaluate the short-term in vitro safety of bevacizumab (Avastin) in human retinal pigment epithelial (ARPE-19), rat neurosensory retinal (R28), and human microvas- cular endothelial (HMVECad) cells. Methods: ARPE-19 and R28 cells were treated with 0.125 mg/mL, 0.25 mg/mL, 0.50 mg/mL, and 1 mg/mL of bevacizumab for 2, 6, and 24 hours. HMVECad cells were treated with 5 ng/mL of vascular endothelial growth factor (VEGF) and 0.125 mg/mL, 0.25 mg/mL, 0.50 mg/mL, and 1 mg/mL of either bevacizumab for 2, 6, and 24 hours or a nonspecific human purified immunoglobulin (IgG) for 24 hours. Cell viability was measured using trypan blue dye exclusion assay. Results: The cell viabilities of ARPE-19 cells, R28 cells, and HMVECad cells treated with bevacizumab were not significantly different (P  0.05) from that of untreated controls. There was no significant difference (P  0.05) between viabilities of HMVECad cells treated with bevacizumab and IgG. Conclusion: This study suggests that bevacizumab, at concentrations at or above the dose normally used in clinical practice, is not toxic to human retinal pigment epithelial, rat neurosensory retinal, or human microvascular endothelial cells in vitro. This report is consistent with the recent report of lack of toxicity of intravitreal bevacizumab in rabbits as well as the lack of apparent toxicity in clinical use. RETINA 26:512–518, 2006 A ge-related macular degeneration (ARMD) and di- abetic retinopathy are two of the leading causes of visual loss in the Western world. 1,2 Vascular endo- thelial growth factor (VEGF) has been implicated as the primary angiogenic stimulus responsible for pathologic neovascularization in ARMD, diabetic ret- inopathy, and neovascular glaucoma as shown by nu- merous studies. 3–12 Pegaptanib sodium (Macugen; From the *Department of Ophthalmology, University of California, Irvine; and the †Department of Ophthalmology, The Ross Eye Institute, University at Buffalo, SUNY, Buffalo, New York. Supported by the Iris and B. Gerald Cantor Foundation, Re- search to Prevent Blindness, The Discovery Eye Foundation, and Skirball Molecular Ophthalmology Program. The authors have no proprietary interests in this study. Reprint requests: Baruch D. Kuppermann, MD, PhD, Depart- ment of Ophthalmology, 125 MedSurge I, University of California, Irvine, California 92697-4375; e-mail: bdkupper@uci.edu 512