Amelia Bai, Kathy Jao, Shuan Dai, Shaheen Shah

Purpose: We present three cases of unilateral delivery and treatment failure despite bilateral intravitreal bevacizumab (IVB) injections for management of retinopathy of prematurity (ROP). Subsequent unilateral re-injection led to successful regression of ROP. Such cases have not previously been reported in the literature. We hypothesise that the uni- lateral lack of response was due to failure of medication delivery despite effective IVB in the other eye, proposing that serum levels of bevacizumab were not high enough to cross the blood-retinal barrier into the contralateral eye.

Methods: Retrospective observational case series con- ducted at Queensland Children’s Hospital.

Results: Three premature infants of gestational age
<25 weeks and birth weight <900 g received bilateral IVB for ROP. Within the following week the three infants had an adequate response in one eye, but treatment fail- ure in the contralateral eye, requiring repeat IVB. There were no documented neurodevelopmental consequences following the second dose of IVB. Conclusion: IVB has been increasingly used off-label to treat ROP. Its anti-vascular endothelial growth factor property directly targets the pathogenesis of ROP, limiting vascular proliferation of the retina. There are, however concerns for systemic absorption of IVB with crossing of the blood-brain barrier and proposed neurodevelopmental sequelae. Our hypothesis, that serum levels of bevacizumab following IVB are not high enough to cross the blood-retinal barrier to affect the contralateral eye, is supported by our three reported cases. These cases contra- dict previously published case reports on apparent contra- lateral effect of unilateral IVB, and provides alternative evidence on an increasingly relevant topic that requires further research and discussion.