Type 1 retinopathy of prematurity in zone I represents the most severe type of ROP and has the worst prognosis. It is unknown whether low-dose bevacizumab will be successful in these severe cases. Also unknown is the timing and extent of peripheral retinal vascularization after low-dose bevacizumab compared with the standard dose. The current study will evaluate whether doses of 0.063 mg and 0.25mg are effective as treatment for type 1 ROP, with ROP and retinal vessels all in zone I.
Infants with type 1 ROP and no prior treatment for ROP will be randomly assigned (1:1) to treatment with either intravitreous bevacizumab 0.063 mg or either intravitreous bevacizumab 0.25 mg. Study exams will be at 1 day, 4 days (if no improvement on day 1), 1, 2, 3, and 4 weeks, and at 2 and 4-months post-treatment (and re-treatment when indicated). Additional study exams will occur at adjusted age 6 and 12 months. Non-study examinations will be at clinician discretion and are likely to occur more often. The primary outcome will be treatment success within each dose group, defined as improvement by the day 4 exam and no recurrence of type 1 ROP or severe neovascularization requiring additional treatment within 4 weeks of injection. Important secondary outcomes include safety and efficacy. refractive outcomes, and the extent of retinal vascularization at 2 and 4 months post-injection between the two dose groups.