Role of Anti-Vascular Endothelial Growth Factor (Anti-VEGF) in the Treatment of Retinopathy of Prematurity: A Narrative Review in the Context of Middle-Income Countries

The rise in preterm births and higher survival rates of premature infants have led to a global increase in retinopathy of prematurity (ROP), a vasoproliferative retinal disorder common in premature infants. ROP is one of the leading causes of childhood blindness. Clinical manifestation of ROP ranges from mild abnormal retinal neovascularization to bilateral retinal detachment and vision loss. The incidence of ROP is higher in middle income countries, including India, which has the highest number of global preterm births. Low birth weight and low gestational age are the primary risk factors for ROP; however, anemia, cardiac defects, blood transfusion, apnea, sepsis, respiratory distress syndrome, high exposure to oxygen and poor postnatal weight gain may also contribute to its development. India has stringent ROP screening guidelines revised in 2018, and screening of infants with either birth weight <2000 grams or gestational age <34 weeks is mandated. With an improved understanding of the pathogenesis of ROP in the past decades and advances in clinical research, treatment for ROP has evolved from cryotherapy to laser retinal ablation. Most recently, anti-vascular endothelial growth factor (anti-VEGF) drugs have emerged as a favorable treatment option for zone-I and II ROP. This article reviews the current approaches for ROP treatment in India with a particular focus on anti-VEGF drugs. The article also integrates the understanding of safety and risk-benefit evaluation of the current approaches in ROP management. The review concluded that there is a need to increase the ROP screening not only for preterm and low birth weight but also for optimal gestational age infants with healthy birth weight. Anti-VEGF therapies have shown improved efficacy, although studies are required to establish the long-term safety.

Long-term peripheral retinal vascular behavior in retinopathy of prematurity patients treated with ranibizumab intravitreal injection as monotherapy using fluorescein angiography

BACKGROUND

Few challenges are faced with the introduction of anti-VEGF agents as a modality of treatment for retinopathy of prematurity. The clinical behavior and time course of regression post injection differ compared to post laser ablation. This study aims to evaluate the long-term peripheral retinal vascularization outcome of Ranibizumab intravitreal injections monotherapy in the treatment of retinopathy of prematurity.

METHOD

Hospital-based quasi-experimental study. Include ROP patients who received intravitreal ranibizumab (IVR), as primary treatment for type 1 ROP. Patients were examined under general anaesthesia to ensure documentation of all junctions of vascular and avascular zones. Images were taken by RetCam III, Phoenix ICON and fluorescein angiography was performed to describe vascular behaviors.

RESULTS

The mean gestational age was 24.67 weeks and the mean postmenstrual age at the time of intravitreal ranibizumab treatment was 36.3 weeks. Fluorescein angiography was performed at 155-288 weeks; most eyes showed two disk diameters of avascular peripheral retina. Only eyes with original aggressive ROP who required a second injection (six eyes) showed extensive peripheral avascular retina reaching zone I (13.64%). Neovascularization was evident in five eyes (11.36%), all with an original aggressive ROP and received multiple injections.

CONCLUSIONS

Ranibizumab treated babies with incomplete retinal vascularization require close and long-term follow-up visits to assess post injection vascular behavior. Peripheral retinal avascular zone of more than two-disc diameters was present in most of the patients evidenced by fluorescein angiography. Babies with initial diagnosis of aggressive ROP are more likely to have persistent peripheral neovascularization.

Different Types of Hyperfluorescence Observed in Post Anti-VEGF Fluorescein Angiographic Patterns in Retinopathy of Prematurity Patients

Purpose

To demonstrate that the demographic and treatment characteristics of retinopathy of prematurity (ROP) eyes showed different types of hyperfluorescence in fluorescein angiography (FA) initially treated with anti-vascular endothelial growth factor (VEGF) agents.

Methods

A consecutive case series of ROP treated with anti-VEGF agents was retrospectively studied. All the patients underwent FA examinations at least 6 months later after treatment. The demographic and treatment characteristics of eyes with or without hyperfluorescence in FA were analyzed. The different types of hyperfluorescence were divided into three groups, including vascular leakage, fibrous membrane, and vascular abnormality.

Results

Two hundred and forty-two eyes of 123 patients with treatment-required ROP were included. Hyperfluorescence was defined in 51/242 eyes, and 2.08 ± 1.11 injections were performed for them, while the eyes without hyperfluorescence received 1.65 ± 0.80 injections (P = 0.013). Vascular leakage was defined in 26/51 hyperfluorescence eyes. The postmenstrual age (PMA) of first injection for the hyperfluorescence group was 38.56 ± 3.24 weeks, which is earlier than that of infants without hyperfluorescence (P = 0.011). More additional treatments were performed in eyes with hyperfluorescence (23.53 vs. 3.66%, P = 0.000). Among them, the eyes with vascular leakage required more additional treatment than eyes without vascular leakage (42.31 vs. 4.00%, P = 0.004). For the 26 eyes with vascular leakage, 11 eyes of 8 patients received further treatments during further follow-up. No significant difference of refractive errors can be defined between different groups.

Conclusion

Eyes with persistent hyperfluorescencein FA after treatment required more anti-VEGF and additional treatments, including laser and PPV. Not all hyperfluorescences were vascular leakage and required additional treatment.

FLUORESCEIN ANGIOGRAPHIC EVALUATION OF PERIPHERAL RETINAL VASCULATURE AFTER PRIMARY INTRAVITREAL RANIBIZUMAB FOR RETINOPATHY OF PREMATURITY

PURPOSE

To evaluate angiographic findings in neonates up to 150 weeks postmenstrual age who received intravitreal ranibizumab for primary treatment of Type 1 retinopathy of prematurity.

METHODS

Retrospective evaluation of fluorescein angiogram findings was completed for 30 eyes of 16 neonates who received intravitreal ranibizumab as primary treatment for Type 1 retinopathy of prematurity between April 2013 and January 2015. Outcome measures included maturity to Zone III, vascular blunting, vascular loops, vascular dilatation, capillary dropout, and vascular fluorescein leakage.

RESULTS

Mean gestational age was 24 weeks and mean postmenstrual age at time of intravitreal ranibizumab treatment was 35 weeks. Fluorescein angiograms performed at 44 weeks to 150 weeks postmenstrual age showed only 50% of eyes reached vascularization to Zone III; 40% had persistent vascular leakage; and ≥90% exhibited vascular blunting, vascular dilatation, and/or capillary dropout.

CONCLUSION

Although intravitreal ranibizumab is effective in initial cessation of Type 1 retinopathy of prematurity, vascularization to Zone III was only achieved in 50% of eyes in our series and most eyes had fluorescein angiography evidence of vascular anomalies. If future studies are performed comparing treatment with laser photocoagulation to anti-vascular endothelial growth factor, fluorescein angiographic studies should be considered to assess the status of the peripheral retinal vasculature to determine treatment effect.

Fluorescein Angiographic Findings of Peripheral Retinal Vasculature after Intravitreal Conbercept versus Ranibizumab for Retinopathy of Prematurity

Purpose

To evaluate angiographic findings of peripheral retina vasculature in retinopathy of prematurity (ROP) neonates who received intravitreal conbercept (IVC) or ranibizumab (IVR).

Methods

Fluorescein angiography (FA) findings were retrospectively evaluated for ROP neonates who received IVC or IVR. Outcome measures included peripheral avascular zone, vascular leakage, vascular blunting, vascular loops, vascular dilatation, arteriovenous shunt, and capillary dropout.

Results

Fifty-four eyes (28 patients) with ROP were included. Twenty-nine eyes (15 patients) received IVC, and 25 eyes (13 patients) received IVR. For infants of the IVC group, the mean gestational age, birth weight, and postmenstrual age (PMA) at the initial treatment were 28.96 ± 2.36 weeks, 1168.8 ± 344.5 g, and 41.22 ± 4.39 weeks, respectively. For the IVR group, they were 28.83 ± 2.34 weeks, 1255.0 ± 356.9 g, and 39.42 ± 2.77 weeks, respectively (P=0.817, 0.522, and 0.075). For the IVC group, FA performed at 71.29-115.43 weeks PMA showed 96.55% of eyes had avascular zone; vascular leakage was found in 24.14% eyes; vascular blunting, vascular dilation, vascular loops, arteriovenous shunt, and capillary dropout were found in 96.55%, 72.41%, 79.31%, 48.28%, and 68.97% eyes, respectively. For the IVR group, FA performed at 65.57-133.71 weeks PMA showed 92.0% of eyes had avascular zone; vascular leakage was found in 40.0% eyes; vascular blunting, dilatation, loops, arteriovenous shunt, and capillary dropout were found in 100%, 60.0%, 64.0%, 36.0%, and 68.0% eyes, respectively.

Conclusion

No significant difference can be observed between the IVC group and IVR group for peripheral vascular structure anomalies with FA evidence. FA studies should be considered to assess the status of the peripheral retinal vasculature to determine therapeutic outcomes and potential functional outcomes.

Enteral Arg-Gln Dipeptide Administration Increases Retinal Docosahexaenoic Acid and Neuroprotectin D1 in a Murine Model of Retinopathy of Prematurity

Purpose

Low levels of the long chain polyunsaturated fatty acid (LCPUFA) docosahexaenoic acid (DHA) have been implicated in retinopathy of prematurity (ROP). However, oral DHA suffers from poor palatability and is associated with increased bleeding in premature infants. We asked whether oral administration of the neutraceutical arginine-glutamine (Arg-Glu) could increase retinal DHA and improve outcomes in a mouse model of oxygen-induced retinopathy (OIR).

Methods

Postnatal day 7 (P7) pups were maintained at 75% oxygen for 5 days and then returned to room air on P12. Pups were gavaged twice daily with Arg-Gln or vehicle from P12 to P17 and eyes were harvested for analysis on P17. Vaso-obliteration and vascular density were assessed on retinal flat mounts and preretinal neovascularization was assessed on retinal cross sections. Retinas were used for measurement of DHA and 10,17S-docosatriene (neuroprotectin D1, NPD1), a key DHA-derived lipid, and for analysis by reverse-phase protein array (RPPA).

Results

With Arg-Gln treatment, retinal DHA and NPD1 levels were increased in OIR pups. Arg-Gln reduced preretinal neovascularization by 39 ± 6% (P < 0.05) relative to vehicle control. This was accompanied by a restoration of vascular density of the retina in the pups treated with Arg-Gln (73.0 ± 3.0%) compared to vehicle (53.1 ± 3.4%; P < 0.05). Arg-Gln dipeptide restored OIR-induced signaling changes toward normoxia and was associated with normalization of insulin-like growth factor receptor 1 signaling and reduction of apoptosis and an increase in anti-apoptosis proteins.

Conclusions

Arg-Gln may serve as a safer and easily tolerated nutraceutical agent for prevention or treatment of ROP.

Efficacy of intravitreal conbercept injection in the treatment of retinopathy of prematurity

BACKGROUND

To evaluate the safety and efficacy of intravitreal conbercept (IVC) injection in the treatment of retinopathy of prematurity (ROP).

METHODS

Patients with ROP who underwent IVC injection in Zhujiang Hospital from June 2015 to July 2016 were studied retrospectively. The primary outcome was defined as the regression of plus disease. The secondary outcomes were defined as the presence of recurrence, number of injections and the final regression of disease.

RESULTS

A total of 48 eyes of 24 patients with ROP were included. Among them, 9 eyes of 5 patients had zone I ROP, 35 eyes of 18 patients had zone II ROP and 4 eyes of 2 patients had aggressive posterior ROP. The mean gestational age was 28.5±1.6 weeks, the mean birth weight was 1209.6±228.6 g, the mean postmenstrual age of first injection was 34.2±1.9 weeks and the mean follow-up period was 31.0±4.7 weeks. Forty of 48 eyes (83.3%) received IVC only once, and the regression of plus disease occurred at an average of 3.5±1.5 weeks after the first injection of conbercept. For eight recurrent eyes (16.7%), four eyes received a second IVC and the remaining four eyes received laser photocoagulation, and the regression of plus disease occurred in 3 weeks. No lens opacity, vitreous haemorrhage, entophthalmia or retinal detachment was observed during follow-up.

CONCLUSION

IVC injection is an effective treatment for ROP.