Commentary: Switching of anti-vascular endothelial growth factor agents in refractory diabetic macular edema

Abstract

Intravitreal injections of anti‐vascular endothelial growth factor (VEGF) are widely accepted as the current gold standard for the treatment of center involving diabetic macular edema (DME). The efficacy of these injections has been proven in many large randomized controlled trials. However, a percentage of patients in these trials showed poor response to the anti‐VEGF agent. Approximately 50% of cases treated with bevacizumab in the Protocol T study did not respond and had persistent macular edema at 2 years.[1] In the Protocol I study, among the patients treated with ranibizumab, 52% failed to achieve ≥2 line vision improvement, and 40% had persistent edema.[2] However, the definition of a non‐responder is not quite certain. The patient is labeled as non‐responder if there is less than 5 letter visual gain or less than 10% decrease in the central retinal thickness after a minimum of 3 injections over 12 weeks time period.[3]