Eye drops with bevacizumab to treat corneal blood vessels in dogs

Abstract

OBJECTIVE: To evaluate the effect and safety of topical anti-human vascular endothelial growth factor bevacizumab in dogs with persistent corneal vascularization. ANIMALS STUDIED: Prospective case series of 15 adult dogs (20 eyes). PROCEDURES: Dogs received 0.25% bevacizumab eye drops BID for 28 days. Follow-ups were scheduled 28 days and 6-7 months after treatment start. Macroscopic findings were scored for conjunctival hyperemia, chemosis, ocular discharge, corneal edema, vascularization, and pigmentation. Vascularized area was assessed by analyzing photographs using an imaging software. RESULTS: The treatment response was variable. Some cases showed a marked reduction in vascularized area and edema, while other eyes had subtle signs of improvement. Vascularization score decreased from 1.5 to 1.1 and vascularized area was reduced by 48.8% after 28 days. A thinning of vessels, consolidation of areal bleedings into fine vascular networks, decrease in distal vessel branching, and a change from blurry vascularized beds into demarcated thin vessels were observed. One dog developed a SCCED 6 months after the last bevacizumab administration. Two dogs died 4 and 4.5 months after the last bevacizumab administration, aged 16 and 12 years, respectively. In all events, a causal relationship is unlikely but cannot be ruled out with certainty. CONCLUSIONS: Our findings suggest that topical 0.25% bevacizumab may be an effective treatment option for corneal vascularization in dogs. Further long-term placebo-controlled studies with larger patient cohorts are recommended to provide scientific evidence of efficacy and to investigate dosage, safety, possible use as a single treatment, and routes of administration.