Intravitreal Ranibizumab Injection for Aggressive Versus Type 1 Prethreshold Retinopathy of Prematurity

Despite advances in the neonatal intensive care units, retinopathy of prematurity (ROP) has become a common reason for blindness and visual disabilities in premature infants so that it accounts for about 5% and 30% of such complications in developed and developing countries. The pathophysiology of ROP is multifactorial. Supplemental oxygen demand and lower gestational age (GA) and birth weight (BW) are among the major risk factors for the occurrence and progression of ROP. Anti-vascular endothelial growth factor (anti-VEGF) agents are a promising modality of treatment for ROP, as laser therapy is associated with disadvantages such as complications from undertreatment or overtreatment, anterior segment burns, hemorrhage, or ischemia, and potentially higher rates of myopia. Ranibizumab is the first approved anti-VEGF treatment for the management of retinopathy, and is a promising alternative to laser therapy. Ranibizumab is a humanized monoclonal recombinant antibody fragment with a shorter half-life and less systemic toxicity than bevacizumab. Its binding affinity is nearly tenfold that of bevacizumab. The plasma half-life of bevacizumab is 17-21 days, while that of ranibizumab is 3 days. Greater systemic absorption of bevacizumab is thought to lead to greater systemic suppression of VEGF. These data may explain the better safety profile of ranibizumab. Type I ROP is defined as any stage of ROP with plus disease in zone I, stage 3 ROP in zone I and stage 2 or 3 ROP with plus disease in zone II . The hallmark of Aggressive-ROP (previously known as Aggressive posterior-ROP) is rapid development of pathological neovascularization and severe plus disease without progression being observed through the typical stages of ROP. It may occur in larger preterm infants and beyond the posterior retina. The aim of this prospective study is to compare the efficacy of intravitreal ranibizumab for type 1 ROP and A-ROP as regard acute ROP regression, recurrence profile, peripheral