Preclinical aspects of anti-VEGF agents for the treatment of wet AMD: ranibizumab and bevacizumab

Systemic Arterial and Venous Thrombotic Events Associated With Anti-Vascular Endothelial Growth Factor Injections: A Meta-Analysis

PURPOSE

To compare the risk of systemic arteriovenous thrombotic events between intravitreal anti-vascular endothelial growth factor (anti-VEGF) and sham injections.

DESIGN

Random-effects meta-analysis.

METHODS

A systematic search was performed on OVID MEDLINE, Embase, and Cochrane Library from January 2005 to August 2023. Our inclusion criteria were randomized controlled trials (RCTs) reporting on systemic arteriovenous events for standard dose intravitreal anti-VEGF agents for any indication.

RESULTS

A total of 20 RCTs reporting on 12,833 eyes were included. There was no significant difference in the risk of any thrombotic event between bevacizumab 1.25 mg and ranibizumab 0.5 mg (Risk ratio (RR) = 0.96, 95% CI = 0.52-1.75, P = .89). There was no significant difference between bevacizumab and ranibizumab when restricting to arterial thrombotic events (RR= 0.88, 95% CI = 0.60-1.30, P = .53) or venous thrombotic events (RR = 1.99, 95% CI =86 0.68-5.82], P = .21). The risk of arterial thrombotic events was similar between aflibercept and bevacizumab (RR = 1.11, 95% CI = 0.60-2.07, P = .74), between aflibercept and ranibizumab (RR= 0.77, 95% CI = 0.49-1.21, P = .26), between brolucizumab and aflibercept (RR= 0.67, 95% CI = 0.32-1.38, P = .27), and between aflibercept and faricimab (RR = 0.96, 95% CI = 0.43-2.17, P = .93). Compared to sham, neither dose of ranibizumab (0.5 mg or 0.3 mg) showed a higher risk of arterial thrombotic events.

CONCLUSIONS

There was a similar risk of systemic arteriovenous thrombotic adverse events between anti-VEGF agents and between ranibizumab and sham injections.

Modeling complex age-related eye disease

Modeling complex eye diseases like age-related macular degeneration (AMD) and glaucoma poses significant challenges, since these conditions depend highly on age-related changes that occur over several decades, with many contributing factors remaining unknown. Although both diseases exhibit a relatively high heritability of >50%, a large proportion of individuals carrying AMD- or glaucoma-associated genetic risk variants will never develop these diseases. Furthermore, several environmental and lifestyle factors contribute to and modulate the pathogenesis and progression of AMD and glaucoma. Several strategies replicate the impact of genetic risk variants, pathobiological pathways and environmental and lifestyle factors in AMD and glaucoma in mice and other species. In this review we will primarily discuss the most commonly available mouse models, which have and will likely continue to improve our understanding of the pathobiology of age-related eye diseases. Uncertainties persist whether small animal models can truly recapitulate disease progression and vision loss in patients, raising doubts regarding their usefulness when testing novel gene or drug therapies. We will elaborate on concerns that relate to shorter lifespan, body size and allometries, lack of macula and a true lamina cribrosa, as well as absence and sequence disparities of certain genes and differences in their chromosomal location in mice. Since biological, rather than chronological, age likely predisposes an organism for both glaucoma and AMD, more rapidly aging organisms like small rodents may open up possibilities that will make research of these diseases more timely and financially feasible. On the other hand, due to the above-mentioned anatomical and physiological features, as well as pharmacokinetic and -dynamic differences small animal models are not ideal to study the natural progression of vision loss or the efficacy and safety of novel therapies. In this context, we will also discuss the advantages and pitfalls of alternative models that include larger species, such as non-human primates and rabbits, patient-derived retinal organoids, and human organ donor eyes.

Investigating bevacizumab and its fragments sustained release from intravitreal administrated PLGA Microspheres: A modeling approach

Intravitreal administrated bevacizumab has emerged as an effective antibody for suppressing VEGF expression in age-related macular degeneration (AMD) therapy. This study discusses certain issues related to the sustained release of bevacizumab from intravitreal poly(lactic-co-glycolic acid) (PLGA) microspheres. A computational model elucidating the ocular kinetics of bevacizumab is demonstrated, wherein the release of the drug from PLGA microspheres is modeled using the Koizumi approach, complemented by an empirical model that links the kinetics of bevacizumab release to a size-dependent hydrolytic degradation of the drug-loaded polymeric microparticles. The results of the simulation were then rigorously validated against experimental data. The as-developed model proved remarkably accurate in predicting the time-concentration profiles obtained following the intravitreal injection of PLGA microspheres of significantly different sizes. Notably, the time-concentration profiles of bevacizumab in distinct ocular tissues were almost unaffected by the size of the intravitreally administered PLGA microparticles. Furthermore, the model successfully predicted the retinal concentration of bevacizumab and its fragments (e.g., ranibizumab) administrated in the form of a solution. As such, this model for drug sustained release and ocular transport holds tremendous potential for facilitating the reliable evaluation of planned anti-VEGF therapies.

LC/MS Assessment of Glycoform Clearance of A Biotherapeutic MAb in Rabbit Ocular Tissues

Many biotherapeutics such as monoclonal antibodies (mAbs) consist of various glycoforms, which can have different PK properties upon administration to animals and human. As a result, it is necessary to monitor the abundance of glycoforms and limit lot-to-lot variability during the manufacturing process. However, limited information is known about the clearance of mAb glycoforms from ocular space upon intravitreal injection. We present here an assessment of glycoform clearance of a biotherapeutic mAb (IgG1) from rabbit vitreous humor, aqueous humor and retina tissue using LC/MS. The results show that G0, G0F and G1F have similar T1/2, while mannose-5 has a longer T1/2 and is cleared slower in rabbit ocular space, which contradicted with what has been reported in the literature in which Mann5 was cleared faster systematically.

Acetazolamide and bevacizumab combination therapy versus bevacizumab monotherapy in macular edema secondary to retinal vein occlusion

PURPOSE

To determine and compare the efficacy of intravitreal bevacizumab (IVB) and oral acetazolamide (OA) combination therapy versus IVB monotherapy in patients with macular edema secondary to retinal vein occlusion (RVO).

METHODS

This randomized clinical trial included 54 eyes of 52 patients with RVO central macular thickness (CMT) of more than 300μm, and best corrected visual acuity (BCVA) between 20/400 and 20/40. Eligible patients were randomly assigned to two groups: (I) IVB and OA (250mg twice daily) combination therapy or (II) IVB monotherapy. Ocular injections were repeated monthly for up to three months; BCVA and CMT were measured monthly.

RESULTS

Both regimens resulted in significant reduction in CMT (534±150μm to 352±90μm in the IVB+OA group, P<0.001; and 580±175μm to 362±90μm in the IVB group, P<0.001); neither showed superiority in this regard. Likewise, BCVA showed significant improvement in both groups (0.87±0.56 to 0.53±0.28 LogMAR in the IVB+OA group, P=0.001; and 0.85±0.62 to 0.46±0.4 LogMAR in the IVB group, P<0.001), with no intergroup difference.

CONCLUSION

Addition of oral acetazolamide to IVB in eyes with macular edema secondary to RVO may not result in additional short-term benefits regarding functional and anatomical outcomes.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT05290948, registered on March 22, 2022. https://clinicaltrials.gov/ct2/show/NCT05290948.

Factors That Can Prolong Ocular Treatment Duration in Age-Related Macular Degeneration

Intravitreal injections of anti-vascular endothelial growth factor (VEGF) agents are used to treat wet age-related macular degeneration (wAMD); however, they are associated with a considerable treatment burden and poor real-world outcomes. The molecular size and charge of anti-VEGF agents influence drug pharmacokinetics in the vitreous and peak drug efficacy. This article reviews the established and novel strategies to prolong drug action, in the vitreal cavity, and thus reduce dosing frequency. Increased ocular residency can be attained by increasing drug size as with large molecules, such as KSI-301; adding polyethylene glycol to pegcetacoplan (APL-2) or avacincaptad pegol to increase molecular size; or binding to other targets that increase molecular size, such as vitreal albumin in the case of BI-X. Faricimab is a bispecific antibody in which the fragment crystallizable portion is engineered to prolong ocular residency and reduce systemic exposure. Conversely, small VEGF-binding molecules, such as brolucizumab, can be administered at higher clinical doses, with the potential for prolonged clinical activity versus larger molecules. Other important considerations include sustained drug delivery routes, such as the ranibizumab port delivery system or subconjunctival or suprachoroidal injection. More effective and longer-lasting treatments are needed for wAMD to prolong drug action and reduce dosing frequency. Several strategies are under investigation and the prevention of vision loss in patients with AMD or other retinal diseases may be attainable in the near future.

Nanomedicine and drug delivery to the retina: current status and implications for gene therapy

Blindness affects more than 60 million people worldwide. Retinal disorders, including age-related macular degeneration (AMD), diabetic retinopathy (DR), and glaucoma, are the leading causes of blindness. Finding means to optimize local and sustained delivery of drugs or genes to the eye and retina is one goal to advance the development of new therapeutics. Despite the ease of accessibility of delivering drugs via the ocular surface, the delivery of drugs to the retina is still challenging due to anatomic and physiologic barriers. Designing a suitable delivery platform to overcome these barriers should enhance drug bioavailability and provide a safe, controlled, and sustained release. Current inventions for posterior segment treatments include intravitreal implants and subretinal viral gene delivery that satisfy these criteria. Several other novel drug delivery technologies, including nanoparticles, micelles, dendrimers, microneedles, liposomes, and nanowires, are now being widely studied for posterior segment drug delivery, and extensive research on gene delivery using siRNA, mRNA, or aptamers is also on the rise. This review discusses the current state of retinal drug/gene delivery and highlights future therapeutic opportunities.

Current and Novel Therapeutic Approaches for Treatment of Neovascular Age-Related Macular Degeneration

Age-related macular degeneration AMD is one of the leading causes of blindness in the elderly population. An advanced form of AMD known as neovascular AMD (nAMD) is implicated as the main attributor of visual loss among these patients. The hallmark feature of nAMD is the presence of neovascular structures known as choroidal neovascular membranes (CNVs), along with fluid exudation, hemorrhages, and subretinal fibrosis. These pathological changes eventually result in anatomical and visual loss. A type of proangiogenic factor known as vascular endothelial growth factor (VEGF) has been known to mediate the pathological process behind nAMD. Therefore, therapy has transitioned over the years from laser therapy that ablates the lesions to using Anti-VEGF to target the pathology directly. In this work, we provide an overview of current and emerging therapies for the treatment of nAMD. Currently approved Anti-VEGF agents include ranibizumab, aflibercept, and brolucizumab. Bevacizumab, also an Anti-VEGF agent, is used to manage nAMD even though this is an off-label use. While Anti-VEGF agents have provided a favorable prognosis for nAMD, they are associated with a substantial financial burden for patients and the healthcare system, due to their high cost as well as the need for frequent repeat treatments and visits. Emerging therapies and studies aim to extend the intervals between required treatments and introduce new treatment modalities that would improve patients’ compliance and provide superior results.

Intravitreal Brolucizumab for Neovascular Age-Related Macular Degeneration in a Vitrectomized Eye

The efficacy of intravitreal anti-VEGF may be reduced in vitrectomized eyes due to accelerated drug clearance. Given its longer durability, brolucizumab may represent a suitable therapeutic option. However, its efficacy in vitrectomized eyes remains to be explored. Herein, we describe the management of a macular neovascularization (MNV) in a vitrectomized eye with brolucizumab after unsuccessful treatment with other anti-VEGF. A 68-year-old male was treated with pars plana vitrectomy for epiretinal membrane in his left eye (LE) in 2018. After surgery, best corrected visual acuity (BCVA) improved to 20/20 with a remarkable reduction of metamorphopsia. After 3 years, the patient returned, presenting visual loss in the LE due to MNV. He was treated with intravitreal bevacizumab injections. However, after the loading phase, an increased lesion size and exudation with worsening BCVA were detected. Therefore, the treatment was switched to aflibercept. However, after three monthly intravitreal injections, further worsening was recorded. Treatment was then switched to brolucizumab. Anatomical and functional improvement was noticed 1 month after the first brolucizumab injection. Two additional injections were performed, and further improvement was recorded with BCVA recovery to 20/20. At the last follow-up visit 2 months after the third injection, no recurrence was detected. In conclusion, determining whether anti-VEGF injections are efficacious for vitrectomized eyes would be helpful for ophthalmologists managing such patients, as well as when considering pars plana vitrectomy in eyes at risk of MNV. In our case, brolucizumab was found to be effective after unsuccessful treatment with other anti-VEGF. Additional studies are required to evaluate the safety and efficacy of brolucizumab for MNV in vitrectomized eyes.

Protein and polypeptide mediated delivery to the eye

Hybrid or recombinant protein-polymers, peptide-based biomaterials, and antibody-targeted therapeutics are widely explored for various ocular conditions and vision correction. They have been noted for their potential biocompatibility, potency, adaptability, and opportunities for sustained drug delivery. Unique to peptide and protein therapeutics, their production by cellular translation allows their precise modification through genetic engineering. To a greater extent than drug delivery to other systems, delivery to the eye can benefit from the combination of locally-targeted administration and protein-based specificity. Consequently, a range of delivery platforms and administration methods have been exploited to address the ocular delivery of peptide and protein biomaterials. This review discusses a sample of preclinical and clinical opportunities for peptide-based drug delivery to the eye.

Ocular Pharmacokinetics of Intravitreally Injected Protein Therapeutics: Comparison among Standard-of-Care Formats

The current standard of care for antivascular endothelial growth factor (VEGF) treatment requires frequent intravitreal (IVT) injections of protein therapeutics, as a result of limited retention within the eye. A thorough understanding of the determinants of ocular pharmacokinetics (PK) and its translation across species is an essential prerequisite for developing more durable treatments. In this work, we studied the ocular PK in macaques of the protein formats that comprise today's anti-VEGF standard of care. Cynomolgus monkeys received a single IVT injection of a single-chain variable fragment (scFv, brolucizumab), antigen-binding fragment (Fab, ranibizumab), fragment crystallizable-fusion protein (Fc-fusion, aflibercept), or immunoglobulin G monoclonal antibody (IgG, VA2 CrossMAb). Drug concentrations were determined in aqueous humor samples collected up to 42 days postinjection using immunoassay methods. The ocular half-life (t_1/2) was 2.28, 2.62, 3.13, and 3.26 days for scFv, Fab, Fc-fusion, and IgG, respectively. A correlation with human t_1/2 values from the literature confirmed the translational significance of the cynomolgus monkey as an animal model for ocular research. The relation between ocular t_1/2 and molecular size was also investigated. Size was inferred from the molecular weight (MW) or determined experimentally by dynamic light scattering. The MW and hydrodynamic radius were found to be good predictors for the ocular t_1/2 of globular proteins. The analysis showed that molecular size is a determinant of ocular disposition and may be used in lieu of dedicated PK studies in animals.

Using different proteolytic enzymes to digest antibody and its impact on stability of antibody mimetics

There are opportunities to formulate antibodies as solid-state depots for local therapy, which would minimise large systemic doses that are typically required. We have developed antibody mimetics known as Fab-PEG-Fab (FpF) that display similar binding affinity and functional activity as IgG antibodies. For head-to-head comparison between FpF and IgG, FpF is prepared from the Fabs obtained by enzymatic digestion of IgGs. Here, we report for the first time that using different enzymes to proteolytically digest IgG plays an important role in stability profile of the obtained Fabs leading in different stability profiles of the final conjugated product such as FpF. We prepared an anti-vascular endothelial growth factor (VEGF) FpF from either clinical Fab_rani (ranibizumab) or Fabs obtained by enzymatic digestion of bevacizumab (IgG) using immobilised papain and gingisKHANTM (KGP) enzyme. The stability of FpFs was then studied after being lyophilised in comparison with both ranibizumab and bevacizumab. Lyophilisation is being evaluated to produce solid material that can be used for depot fabrication. We observed that using immobilised papain to digest IgG resulted in the heterogenous isomers Fab leading to the preparation of heterogenous FpF_beva-papain mimetic that underwent aggregation during lyophilisation. However, using KGP enzyme generated a homogenous intact Fab_beva-KGP as determined by mass spectral analysis. Interestingly, the FpF mimetics prepared from the homogenous Fabs (Fab_rani and Fab_beva-KGP), displayed greater stability compared to their starting bevacizumab and ranibizumab after being lyophilised as determined by DLS analysis. There is a potential to lyophilize FpFs to be used to fabricate solid-state depots.

Preclinical assessment of intravitreal ramucirumab: in vitro and in vivo safety profile

Background

Anti-angiogenic drugs remain the mainstay therapy for several vascular retinal pathologies. The repurposing of approved anti-angiogenic drugs for use in ophthalmology can increase therapeutic options and reduce costs. The purpose of this study was to investigate the ocular safety profile of intravitreal (IVT) ramucirumab, an approved anti-vascular endothelial growth factor molecule for systemic treatment, using cell culture and animal models.

Methods

The cytotoxicity of ramucirumab at different concentrations was evaluated in human retinal pigment epithelial cells (ARPE-19) using the MTT assay. In addition, 250 or 500 µg of ramucirumab or vehicle was injected in the eye of 16 chinchilla rabbits. The eyes were evaluated by ophthalmoscopy, electroretinography, spectral-domain optical coherence tomography (SD-OCT) and by light and transmission electron microscopy.

Results

Electroretinography or SD-OCT did not detect functional or morphological alterations at 24 h or one week after injection. Light and transmission electron microscopy confirmed the absence of major signs of toxicity, although we found a statistically significant reduction in ganglion cell number between the controls and the eyes that received 500 µg of ramucirumab after 7 days. Compared to lower concentrations, 500 µg of ramucirumab caused reduction in cell viability and changes in morphology in ARPE-19 cells. Compared to the baseline, ocular and serum osmolarity showed no difference after IVT injection at all timepoints.

Conclusion

In conclusion, IVT injection of ramucirumab in rabbits is safe and does not cause functional damage to the retina. At the lower dose tested in vivo (250 µg), the morphology and ultrastructural anatomy were normal at 24 h and 1 week after the injection. However, the 500 µg dose can cause a decrease in ganglion cell number seven days after the injection.

Understanding the Half-Life Extension of Intravitreally Administered Antibodies Binding to Ocular Albumin

The burden associated with frequent injections of current intravitreal (IVT) therapeutics may be reduced by long-acting delivery strategies. Binding to serum albumin has been shown to extend the ocular half-life in rabbits, however, the underlying molecular mechanisms and translational relevance remain unclear. The aim of this work was to characterize the in vitro and in vivo formation of complexes between human serum albumin (HSA) and an antigen-binding fragment of a rabbit antibody linked to an anti-HSA nanobody (FabA). The ocular and systemic pharmacokinetics of 3H-labeled FabA (0.05 mg/eye IVT) co-formulated with HSA (1 and 15 nmol/eye) were assessed in Dutch belted rabbits. Next, FabA was incubated in vitreous samples from cynomolgus monkeys and human donors (healthy and diseased) supplemented with species-specific serum albumin. Finally, the FabA-albumin complexes formed in vitro and in vivo were analyzed by radio-size exclusion chromatography. A 3-fold increase in FabA vitreal exposure and half-life was observed in rabbits co-administered with 15 nmol HSA compared to 1 nmol and a control arm. The different pharmacokinetic behavior was explained with the formation of higher molecular weight FabA-albumin complexes. The analysis of vitreous samples revealed the existence of predominantly 1:1 complexes at endogenous or low concentrations of supplemented albumin. A shift towards 1:2 complexes was observed with increasing albumin concentrations. Overall, these results suggest that endogenous vitreal albumin concentrations are insufficient for half-life extension and warrant supplementation in the dosing formulation.

Intravitreal hydrogels for sustained release of therapeutic proteins

This review highlights how hydrogel formulations can improve intravitreal protein delivery to the posterior segment of the eye in order to increase therapeutic outcome and patient compliance. Several therapeutic proteins have shown excellent clinical successes for the treatment of various intraocular diseases. However, drug delivery to the posterior segment of the eye faces significant challenges due to multiple physiological barriers preventing drugs from reaching the retina, among which intravitreal protein instability and rapid clearance from the site of injection. Hence, frequent injections are required to maintain therapeutic levels. Moreover, because the world population ages, the number of patients suffering from ocular diseases, such as age-related macular degeneration (AMD) and diabetic retinopathy (DR) is increasing and causing increased health care costs. Therefore, there is a growing need for suitable delivery systems able to tackle the current limitations in retinal protein delivery, which also may reduce costs. Hydrogels have shown to be promising delivery systems capable of sustaining release of therapeutic proteins and thus extending their local presence. Here, an extensive overview of preclinically developed intravitreal hydrogels is provided with attention to the rational design of clinically useful intravitreal systems. The currently used polymers, crosslinking mechanisms, in vitro/in vivo models and advancements are discussed together with the limitations and future perspective of these biomaterials.

Central Role of Oxidative Stress in Age-Related Macular Degeneration: Evidence from a Review of the Molecular Mechanisms and Animal Models

Age-related macular degeneration (AMD) is a common cause of visual impairment in the elderly. There are very limited therapeutic options for AMD with the predominant therapies targeting vascular endothelial growth factor (VEGF) in the retina of patients afflicted with wet AMD. Hence, it is important to remind readers, especially those interested in AMD, about current studies that may help to develop novel therapies for other stages of AMD. This study, therefore, provides a comprehensive review of studies on human specimens as well as rodent models of the disease, to identify and analyze the molecular mechanisms behind AMD development and progression. The evaluation of this information highlights the central role that oxidative damage in the retina plays in contributing to major pathways, including inflammation and angiogenesis, found in the AMD phenotype. Following on the debate of oxidative stress as the earliest injury in the AMD pathogenesis, we demonstrated how the targeting of oxidative stress-associated pathways, such as autophagy and nuclear factor erythroid 2-related factor 2 (Nrf2) signaling, might be the futuristic direction to explore in the search of an effective treatment for AMD, as the dysregulation of these mechanisms is crucial to oxidative injury in the retina. In addition, animal models of AMD have been discussed in great detail, with their strengths and pitfalls included, to assist inform in the selection of suitable models for investigating any of the molecular mechanisms.

Evaluation of long-term intravitreal anti-vascular endothelial growth factor injections on renal function in patients with and without diabetic kidney disease

Background

Administering anti-vascular endothelial growth factor (anti-VEGF) by intraocular injection has been shown to have a safe systemic profile. Nevertheless, incidents of acute kidney injury following anti-VEGF injection have been reported. We assessed the long-term effect of multiple intravitreal anti-VEGF injections on measures of renal function in patients with diabetes including rate of change of estimated glomerular filtration rate (eGFR) and urine albumin-to-creatinine ratio (ACR).

Methods

A retrospective review of patients receiving diabetic macular oedema (DMO) treatment was undertaken. Serum creatinine, ACR, number of intravitreal anti-VEGF injections and clinical characteristics were collected from electronic healthcare records (EHR). A co-efficient of eGFR and ACR change with time was calculated over a mean duration of 2.6 years. Regression modelling was used to assess variation in the number of anti-VEGF injections and change in eGFR and ACR.

Results

The EHR of 85 patients with DMO (59% male, 78% type 2 diabetes mellitus [T2DM]) were reviewed. On average, 26.8 intravitreal anti-VEGF injections were given per patient over a mean duration of 31 months. No association between increasing number of anti-VEGF injections and rate of eGFR decline (beta = 0.04, 95% confidence intervals [CI]: − 0.02, 0.09; p = 0.22) or ACR change over time (beta = 0.02, CI: − 0.19, 0.23; p = 0.86) was detected, following adjustment for hypertension, cerebrovascular disease, T2DM, and medications taken.

Conclusion

Our data suggests regular long-term intravitreal VEGF inhibition does not significantly alter the rate of change in eGFR and/or ACR with increasing number of treatment injections.

Comparing The Efficacy Of An Anti-Human VEGF-A Neutralizing Antibody Versus Bevacizumab On A Laser-Induced Choroidal Neovascularization (CNV) Rhesus Monkey Model

Purpose

To evaluate the efficacy of a therapy on improving characteristics of laser-induced choroidal neovascularization (CNV) via single intravitreal injection of a humanized anti-human VEGF monoclonal antibody (PRO-169) versus bevacizumab in a rhesus monkey model.

Methods

To induce experimental CNV, small high-energy laser spots were used to treat several areas, around the macula in the retinas of monkeys at Day −21. Eighteen rhesus monkeys were used for CNV induction. The efficacy endpoints were fluorescein leakage by FFA and retinal thickness by OCT. FFA examinations were performed 19 days after induction. Appropriate animals were enrolled for treatment and randomly divided into 3 groups: bevacizumab (n=5, 7 eyes), PRO-169 (n=5, 7 eyes), and vehicle controls (n=4, 7 eyes).

Results

In 25 of 36 (69.4%) eyes, CNV lesions were identified. The average percent change of retinal thickness in the eyes of bevacizumab group was −159.3±62.2% and −154.0±45.1% (p<0.01 vs Vehicle) at Day 14 and Day 28, respectively; in the eyes of PRO-169 group it was −131.6±68.7% and −131.5±63.8% (p<0.01 vs Vehicle), respectively. The average percent change of leakage area in the eyes of bevacizumab group was −75.3±49.4% and −78.0±42.6% (p<0.01 vs Vehicle) at Day 14 and Day 28, respectively; in the eyes of PRO-169 group it was −82.0±19.3% and −81.4±21.0% (p<0.01 vs Vehicle), respectively. There were no abnormalities found in behavior, skin and hair, excretion and overall eye appearance before and after treatment in all groups.

Conclusion

After photocoagulation, the eyes enrolled in this studio showed CNV related characteristics including increased retinal thickness, and fluorescein leakage at laser spots. PRO-169 (1.25 mg per eye) can reduce the retinal thickness and fluorescein leakage area after treatment for 14 and 28 days in this rhesus monkeys model, without toxic effect or adverse events. These findings suggested that PRO-169 can inhibit CNV.

Important Metabolites in Maintaining Folate Cycle, Homocysteine, and Polyamine Metabolism Associated with Ranibizumab Treatment in Cultured Human Tenon's Fibroblasts

The anti-fibrotic properties of ranibizumab have been well documented. As an antagonist to vascular endothelial growth factor (VEGF), ranibizumab works by binding and neutralizing all active VEGF-A, thus limiting progressive cell growth and proliferation. Ranibizumab application in ocular diseases has shown remarkable desired effects; however, to date, its antifibrotic mechanism is not well understood. In this study, we identified metabolic changes in ranibizumab-treated human Tenon's fibroblasts (HTFs). Cultured HTFs were treated for 48 h with 0.5 mg/mL of ranibizumab and 0.5 mg/mL control IgG antibody which serves as a negative control. Samples from each group were injected into Agilent 6520 Q-TOF liquid chromatography/mass spectrometer (LC/MS) system to establish the metabolite expression in both ranibizumab treated cells and control group. Data obtained was analyzed using Agilent Mass Hunter Qualitative Analysis software to identify the most regulated metabolite following ranibizumab treatment. At p-value < 0.01 with the cut off value of two-fold change, 31 identified metabolites were found to be significantly upregulated in ranibizumab-treated group, with six of the mostly upregulated having insignificant role in fibroblast cell cycle and wound healing regulations. Meanwhile, 121 identified metabolites that were downregulated, and seven of the mostly downregulated are significantly involved in cell cycle and proliferation. Our findings suggest that ranibizumab abrogates the tissue scarring and wound healing process by regulating the expression of metabolites associated with fibrotic activity. In particular, we found that vitamin Bs are important in maintaining normal folate cycle, nucleotide synthesis, and homocysteine and spermidine metabolism. This study provides an insight into ranibizumab's mechanism of action in HTFs from the perspective of metabolomics.

Early changes in macular optical coherence tomography parameters after Ranibizumab intravitreal injection in patients with exsudative age-related macular degeneration

Background

Methods

Results

Conclusion

Intravitreal bevacizumab upregulates transthyretin in experimental branch retinal vein occlusion

Purpose

To identify retinal protein changes that mediate beneficial effects of intravitreal bevacizumab in experimental branch retinal vein occlusion (BRVO).

Methods

In six Danish Landrace pigs, BRVO was induced with argon laser in both eyes. After BRVO was induced, the right eye of each animal was given an intravitreal injection of bevacizumab while the left eye was treated with saline water. The retinas were collected 15 days after BRVO, and differentially expressed proteins were analyzed with tandem mass tags-based mass spectrometry. Validation of statistically significantly changed proteins was performed with immunohistochemistry and western blotting.

Results

Fluorescein angiography showed no recanalization of the occluded vessels. A total of 4,013 proteins were successfully identified and quantified. Nine proteins were statistically significantly changed following bevacizumab intervention. In experimental BRVO, bevacizumab treatment resulted in upregulation of transthyretin (TTR) and pantothenate kinase 3. Bevacizumab downregulated protocadherin 7, protein FAM192A, and ATP synthase protein 8. Immunohistochemistry revealed that TTR was highly abundant in the choroid following bevacizumab intervention.

Conclusions

Bevacizumab intervention in experimental BRVO resulted in an increased level of TTR. This is the second study in which we showed an increased retinal level of TTR following anti-vascular endothelial growth factor (VEGF) intervention in experimental BRVO. We hypothesize that there is an interaction between TTR and VEGF and that bevacizumab may exert a beneficial effect on the retina by upregulating TTR.

The Developing Regorafenib Eye drops for neovascular Age-related Macular degeneration (DREAM) study: an open-label phase II trial

AIMS

This programme investigated topical regorafenib, a multikinase inhibitor, in patients with neovascular age-related macular degeneration (nAMD).

METHODS

Topical regorafenib was investigated in an open-label, phase IIa/b study in which patients with choroidal neovascularization (CNV) secondary to nAMD received regorafenib (25 μl, 30 mg ml^-1 ) three times a day for 12 weeks. The primary endpoint of the phase II/a/b study was mean change in best-corrected visual acuity (BCVA) from baseline to weeks 4 and 12.

RESULTS

In nAMD patients (N = 51), mean changes in BCVA were +1.2 [90% confidence interval (CI) -0.61, 2.97] and -2.4 (90% CI -4.18, -0.54) letters at weeks 4 and 12, respectively. Ocular treatment-emergent adverse events (TEAEs) (study eye) were reported in 21 patients by week 12. There was one serious ocular TEAE (visual acuity reduced) that was not drug related. Twenty patients required rescue (intravitreal ranibizumab).

CONCLUSIONS

The programme was terminated after phase IIa ended because efficacy was lower than with current nAMD treatments. According to elaborate post hoc analyses, the most likely reason was insufficient exposure in the target compartment (back of the eye).

One-step solid-oil-water emulsion for sustained bioactive ranibizumab release

BACKGROUND

The advent of therapeutic proteins highlights the need for delivery systems that protect and extend the duration of its action. Ranibizumab-VEGF is one such drug used for treating wet AMD. This paper describes a facile method to sustain bioactive ranibizumab release from PLGA-based particles.

METHODS

Two emulsion techniques were explored namely: water-in-oil-in-water (WOW) and solid-in-oil-in-water (SOW) emulsion. The bioactivity of ranibizumab was evaluated by comparing its binding capability to VEGF, measured with ELISA to total protein measured by microBCA.

RESULTS

During the emulsion process, contact of ranibizumab with the water-oil interface is the main destabilizing factor and this can be prevented with the use of amphiphilic PVA and solid-state protein in WOW and SOW emulsion respectively. In vitro release of the ranibizumab-loaded particles indicated that a 15-day release could be achieved with SOW particles while the WOW particles generally suffered from a burst release. Released ranibizumab was capable of inhibiting endothelial cell growth indicating its retention of bioactivity. The suppression of burst release from the SOW particles was attributed to the relatively smooth surface morphology of the SOW microparticles.

CONCLUSIONS

The use of SOW encapsulation in modulating ranibizumab release while maintaining their bioactivity has been highlighted.

Influence of aflibercept on platelet activation profile

Aflibercept appears to accumulate in systemic circulation following intravitreal injections in therapy of neovascular age-related macular degeneration. This gives raise to the question of whether aflibercept affects platelets and their function such as activation and aggregation, which are substantial in the pathogenesis of an arterial thromboembolic event (ATE). In order to determine the effect of aflibercept in platelet activation, platelets from healthy volunteers were treated with aflibercept and its solvents at equal concentrations (0.04 μg/mL - 4 μg/mL - 40 μg/mL - 400 μg/mL - 4 mg/mL) for 10 and 30 min before addition of agonists. IgG1 antibody was used as a control. The surface expression of GPIIb/IIIa, P-selectin, and platelet-bound stromal-cell-derived factor-1, which are potential blood biomarkers for ATEs, was determined on resting and activated platelets by the multispectral imaging flow cytometry, combining the features of flow cytometry with fluorescence microscopy. Platelet aggregation was assessed with light transmission aggregometry. To determine whether aflibercept directly interacts with platelets, aflibercept was labeled with the fluorescence FITC. Co-treatment of platelets with thrombin or PAR-4-AP and aflibercept resulted in increased activation of the fibrinogen receptor GPIIb/IIIa in comparison to controls (P < 0.05). Interestingly, the expression of platelet-derived P-selectin and SDF-1 was not affected by aflibercept, except thrombin-activated CD62P with 0.04 μg/mL aflibercept (aflibercept vs. its solvent: MSI = 1.54, IC = 1.201-1.879 vs. MSI = 1.37, IC = 1.136-1.604 [P = 0.031]) and SDF-1 with 4 mg/mL aflibercept (aflibercept vs. its solvent: MSI = 1.971, IC = 1.206-2.737 vs. MSI = 1.200, IC = 0.738-1.662 [P = 0.041]). Although the levels of platelet-bound aflibercept-FITC were significantly increased in all activated platelets, no effect was observed in platelet aggregation. Albeit no impact of aflibercept was found on platelet aggregation under the studied experimental conditions, the increased activation of the fibrinogen receptor GPIIb/IIIa and the presence of a direct interaction between aflibercept and platelets may partially explain the risk of ATE in patients under aflibercept treatment due to FcγRIIa mediated αIIbβ3 outside-in integrin signaling and transport of aflibercept into platelets. Therefore, the Fc domain seems to be involved in interactions between aflibercept and platelets. Further research is needed to explain the role of Fc containing aflibercept in the pathogenesis of drug-associated vascular events involving platelets, coagulation cascade, extracellular matrix proteins and other cells.

Intraocular Penetration of a vNAR: In Vivo and In Vitro VEGF165 Neutralization

Variable new antigen receptor domain (vNAR) antibodies are novel, naturally occurring antibodies that can be isolated from naïve, immune or synthetic shark libraries. These molecules are very interesting to the biotechnology and pharmaceutical industries because of their unique characteristics related to size and tissue penetrability. There have been some approved anti-angiogenic therapies for ophthalmic conditions, not related to vNAR. This includes biologics and chimeric proteins that neutralize vascular endothelial growth factor (VEGF)₁₆₅, which are injected intravitreal, causing discomfort and increasing the possibility of infection. In this paper, we present a vNAR antibody against human recombinant VEGF₁₆₅ (rhVEGF₁₆₅) that was isolated from an immunized Heterodontus francisci shark. A vNAR called V13, neutralizes VEGF₁₆₅ cytokine starting at 75 μg/mL in an in vitro assay based on co-culture of normal human dermal fibroblasts (NHDFs) and green fluorescence protein (GFP)-labeled human umbilical vein endothelial cells (HUVECs) cells. In the oxygen-induced retinopathy model in C57BL/6:Hsd mice, we demonstrate an endothelial cell count decrease. Further, we demonstrate the intraocular penetration after topical administration of 0.1 μg/mL of vNAR V13 by its detection in aqueous humor in New Zealand rabbits with healthy eyes after 3 h of application. These findings demonstrate the potential of topical application of vNAR V13 as a possible new drug candidate for vascular eye diseases.

Dexamethasone intravitreal implant downregulates PDGFR-α and upregulates caveolin-1 in experimental branch retinal vein occlusion

A dexamethasone (DEX) intravitreal implant (OZURDEX) provides an effective treatment of inflammation secondary to branch retinal vein occlusion (BRVO). Retinal proteome changes which mediate the beneficial effects of the implant remain poorly understood. To study retinal proteome changes in BRVO following an intervention with a DEX implant this study combined an experimental model of BRVO with proteomic techniques. In eight Danish Landrace pigs experimental BRVO was induced in both eyes using argon laser. After inducing BRVO a DEX implant was injected into the right eye of each animal while the left control eye was given an identical injection without an implant. Fifteen days after BRVO and DEX implant intervention the retinas were excised and analyzed with tandem mass tag based mass spectrometry. A total of 26 significantly changed proteins were identified. DEX intervention reduced the retinal levels of platelet-derived growth factor receptor-α (PDGFR-α) and vascular endothelial growth factor receptor 2 (VEGFR-2). DEX treatment resulted in increased levels of caveolin-1, peptidyl-prolyl cis-trans isomerase FKBP5 and transgelin. Changes in PDGFR-α and caveolin-1 were confirmed with immunohistochemistry. In BRVO treated with the DEX implant a strong reaction for caveolin-1 was observed in the innermost retinal layers. DEX implant intervention may inhibit PDGF signaling by decreasing the retinal level of PDGFR-α while an increased content of caveolin-1 may help maintain the integrity of the blood-retinal barrier.

Models of retinal diseases and their applicability in drug discovery

INTRODUCTION

The impact of vision debilitating diseases is a global public health concern, which will continue until effective preventative and management protocols are developed. Two retinal diseases responsible for the majority of vision loss in the working age adults and elderly populations are diabetic retinopathy (DR) and age-related macular degeneration (AMD), respectively. Model systems, which recapitulate aspects of human pathology, are valid experimental modalities that have contributed to the identification of signaling pathways involved in disease development and consequently potential therapies. Areas covered: The pathology of DR and AMD, which serve as the basis for designing appropriate models of disease, is discussed. The authors also review in vitro and in vivo models of DR and AMD and evaluate the utility of these models in exploratory and pre-clinical studies. Expert opinion: The complex nature of non-Mendelian diseases such as DR and AMD has made identification of effective therapeutic treatments challenging. However, the authors believe that while in vivo models are often criticized for not being a 'perfect' recapitulation of disease, they have been valuable experimentally when used with consideration of the strengths and limitations of the experimental model selected and have a place in the drug discovery process.

ApoA-I Mimetic Peptide 4F Reduces Age-Related Lipid Deposition in Murine Bruch's Membrane and Causes Its Structural Remodeling

PURPOSE

Accumulation of lipoprotein-derived lipids including esterified and unesterified cholesterol in Bruch's membrane of human eyes is a major age-related change involved in initiating and sustaining soft drusen in age-related macular degeneration (AMD). The apolipoprotein (apo) A-I mimetic peptide 4F is a small anti-inflammatory and anti-atherogenic agent, and potent modifier of plasma membranes. We evaluated the effect of intravitreally-injected 4F on murine Bruch's membrane.

METHODS

We tested single intravitreal injections of 4F doses (0.6 µg, 1.2 µg, 2.4 µg, and placebo scrambled peptide) in ApoE^null mice ≥10 months of age. After 30 days, mice were euthanized. Eyes were processed for either direct immunofluorescence detection of esterified cholesterol (EC) in Bruch's membrane whole mounts via a perfringolysin O-based marker linked to green fluorescent protein or by transmission electron microscopic visualization of Bruch's membrane integrity. Fluorescein isothiocyanate-conjugated 4F was traced after injection.

RESULTS

All injected eyes showed a dose-dependent reduction of Bruch's membrane EC with a concomitant ultrastructural improvement compared to placebo treated eyes. At a 2.4 µg dose of 4F, EC was reduced on average by ~60% and Bruch's membrane returned to a regular pentalaminar structure and thickness. Tracer studies confirmed that injected 4F reached intraocular targets.

CONCLUSION

We demonstrated a highly effective pharmacological reduction of EC and restoration of Bruch's membrane ultrastructure. The apoA-I mimetic peptide 4F is a novel way to treat a critical AMD disease process and thus represents a new candidate for treating the underlying cause of AMD.

Transfer of single dose of intravitreal injection of ranibizumab and bevacizumab into milk of sheep

AIM

To investigate whether single-dose intravitreal injections of bevacizumab and ranibizumab transfer into milk.

METHODS

This study included lactating 12 sheep and a single 3-month old suckling lamb of each sheep. Two groups consisting of 6 sheep and their lambs were constituted; the ranibizumab group and the bevacizumab group before the administration of intravitreal injections, blood and milk samples were obtained from all sheep and, following the injections, blood and milk samples of all sheep and blood samples of all lambs were collected at regular time points. Serum and milk concentrations of bevacizumab and ranibizumab were measured using an enzyme-linked immunosorbent assay (ELISA) kit. The limit of determination was 0.9 ng/mL for bevacizumab and 0.62 ng/mL for ranibizumab.

RESULTS

At 6h after intravitreal injections, bevacizumab concentration was above the limit of determination in the blood of all sheep. At 3wk, when the study was terminated, bevacizumab concentrations were high in 4 sheep. Even though bevacizumab concentrations in milk showed fluctuations, the drug transferred into the milk of all sheep at detectable concentrations. Ranibizumab drug concentrations in the blood and milk of sheep and those in the blood of lambs were below the limit of determination by the ELISA kit.

CONCLUSION

This sheep model study demonstrate that intravitreal injection of ranibizumab, which did not transfer into the milk of sheep and suckling lambs, is safer than bevacizumab during lactation period.

Biological Modulation of Mouse RPE Cells in Response to Subthreshold Diode Micropulse Laser Treatment

Many clinical trials have demonstrated the effectiveness of subthreshold phototherapy with no visible damage in retinal vascular diseases, such as diabetic retinopathy. We aimed primarily to investigate the effect of subthreshold diode micropulse laser (SDM) treatment on mouse retinal pigmented epithelium (RPE) cells. The expression of angiogenesis-modulating cytokines in response to SDM was also explored. The least toxic laser dose was selected by measuring cell viability with MTT assay and 5 % duty cycle (DC) was chosen for use in further experiments. RPE cells were treated with laser-induced radiation ranging from 0 to 400 mW for 24 h. The apoptotic rate of RPE cells was assessed by flow cytometry. Expressions of vascular endothelial growth factor A (VEGF-A), transforming growth factor beta (TGF-β), basic fibroblast growth factor (bFGF), and pigment epithelium-derived factor (PEDF) were determined by Western Blotting and real-time PCR, respectively. After 24 h of laser irradiation, cell viability was reduced dose dependently and the effect was significant compared to the controls (P < 0.05). In addition, laser treatment with intensities of 100 and 200 mW with DC of 5 % produced no significant effect on cell viability and apoptosis as compared with the control group (P > 0.05). The protein and mRNA expressions of angiogenic stimulators (VEGF-A, TGF-β, and bFGF) were significantly down-regulated (P < 0.05), whereas those of the angiogenic inhibitor (PEDF) were up-regulated (P < 0.05). No significant difference was found between the cells treated with different intensities of laser radiation (P > 0.05). Our results showed that SDM treatment of the RPE cells suppressed the expression of choroid neovasculization-promoting cytokines and up-regulated the angiogenic inhibitor, PEDF without damaging the cells. Further investigation is needed to understand the mechanism and to optimize the use of SDM as a novel method of treatment for retinal vascular diseases.

Combination of Intravitreal Injection of Ranibizumab and Photocoagulation for the Treatment of Aggressive Posterior Retinopathy of Prematurity with Vitreous Hemorrhage

To investigate the efficacy of intravitreal ranibizumab (IVR) combined with laser photocoagulation for aggressive posterior retinopathy of prematurity (AP-ROP) patients with vitreous hemorrhage, we conducted a retrospective observational case series study. A total of 37 eyes of 20 patients' medical records were reviewed. Patients first received IVR (0.25 mg/0.025 mL) and later photocoagulation. The mean postconceptual age of injection was 34.6 ± 1.4 weeks, and the mean follow-up period was 39.3 ± 8.3 weeks. During the follow-up, 96.6% eyes had various degree of rapid absorption of vitreous hemorrhage after IVR. The mean time of received first photocoagulation after IVR was 4.8 ± 2.9 weeks. Ten (27.0%) eyes received second laser therapy and the mean time of second laser therapy after IVR was 3.2 ± 0.8 weeks. All eyes exhibited adequate regression of ROP and were stable with attached retina. Fibrosis membrane was observed in seven eyes (18.9%) and three of them demonstrated mild ectopic macula. No significant side effects related to IVR were observed. So IVR could be conducted as primary treatment of AP-ROP associated with vitreous hemorrhage, which can improve the fundus visibility, followed by conventional photocoagulation. Further randomized controlled trials are necessary to compare the clinical efficacy and safety with conventional interventions.

Photo-Modulated Therapeutic Protein Release from a Hydrogel Depot Using Visible Light

The use of biomacromolecular therapeutics has revolutionized disease treatment, but frequent injections are required owing to their short half-life in vivo. Thus there is a need for a drug delivery system that acts as a reservoir and releases the drug remotely "on demand". Here we demonstrate a simple light-triggered local drug delivery system through photo-thermal interactions of polymer-coated gold nanoparticles (AuNPs) inside an agarose hydrogel as therapeutic depot. Localized temperature increase induced by the visible light exposure caused reversible softening of the hydrogel matrix to release the pre-loaded therapeutics. The release profile can be adjusted by AuNPs and agarose concentrations, light intensity and exposure time. Importantly, the biological activity of the released bevacizumab was highly retained. In this study we demonstrate the potential application of this facile AuNPs/hydrogel system for ocular therapeutics delivery through its versatility to release multiple biologics, compatibility to ocular cells and spatiotemporal control using visible light.

Retinal proteome changes following experimental branch retinal vein occlusion and intervention with ranibizumab

Animal models of experimental branch retinal vein occlusion (BRVO) provide a unique opportunity to study protein changes directly in retinal tissue. Results from these experimental models suggest that experimental BRVO is associated with an upregulation of extracellular matrix remodeling and adhesion signaling processes. To study whether these processes could be blocked by inhibition of VEGF-A, a porcine model of experimental BRVO was combined with proteomic analyses. In six Danish Landrace pigs experimental BRVO was induced with argon laser in both eyes. After 24 h an injection of 0.05 mL ranibizumab was given in the right eyes of the animals while left eyes received an injection of 0.05 mL 9 mg/mL sodium chloride water. Retinas were dissected three days after BRVO and the retinal samples were analyzed with label-free quantification as well as tandem mass tag based proteomics. In retinas treated with ranibizumab five proteins exhibited statistically significant changes in content with both proteomic techniques. These five proteins, which were all decreased in content, included integrin β-1, peroxisomal 3-ketoacyl-CoA thiolase, OCIA domain-containing protein 1, calnexin and 40S ribosomal protein S5. As anti-integrin therapies are under development for inhibition of angiogenesis in retinal diseases it is interesting that inhibition of VEGF-A in itself resulted in a small decrease in the content of integrin β-1. The decreased content of integrin β-1 indicates that extracellular matrix remodeling and adhesion processes associated with BRVO are at least partly reversed through inhibition of VEGF-A.

DETECTION OF NONEXUDATIVE CHOROIDAL NEOVASCULARIZATION IN AGE-RELATED MACULAR DEGENERATION WITH OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY

PURPOSE

To evaluate eyes with age-related macular degeneration and high-risk characteristics for choroidal neovascularization (CNV) with optical coherence tomographic (OCT) angiography to determine whether earlier detection of CNV is possible.

METHODS

Eyes with drusen, pigmentary changes, and with CNV in the fellow eye were scanned with a 70-kHz spectral domain OCT system (Optovue RTVue-XR Avanti). The split-spectrum amplitude-decorrelation angiography (SSADA) algorithm was used to distinguish blood flow from static tissue. Two masked graders reviewed scans for CNV, defined as flow in the outer retinal/sub-RPE slab. Choroidal neovascularization flow area repeatability and between-grader reproducibility were calculated.

RESULTS

Of 32 eyes, 2 (6%) were found to have Type 1 CNV with OCT angiography. The lesions were not associated with leakage on fluorescein angiography or fluid on OCT. One case was followed for 8 months without treatment, and the CNV flow area enlarged slightly without fluid buildup on OCT or vision loss. Between-grader reproducibility of the CNV flow area was 9.4% (coefficient of variation) and within-visit repeatability was 5.2% (pooled coefficient of variation).

CONCLUSION

Optical coherence tomographic angiography can detect the presence of nonexudative CNV, lesions difficult to identify with fluorescein angiography and OCT. Further study is needed to understand the significance and natural history of these lesions.

Mining Retrospective Data for Virtual Prospective Drug Repurposing: L-DOPA and Age-related Macular Degeneration

BACKGROUND

Age-related macular degeneration (AMD) is a leading cause of visual loss among the elderly. A key cell type involved in AMD, the retinal pigment epithelium, expresses a G protein-coupled receptor that, in response to its ligand, L-DOPA, up-regulates pigment epithelia-derived factor, while down-regulating vascular endothelial growth factor. In this study we investigated the potential relationship between L-DOPA and AMD.

METHODS

We used retrospective analysis to compare the incidence of AMD between patients taking vs not taking L-DOPA. We analyzed 2 separate cohorts of patients with extensive medical records from the Marshfield Clinic (approximately 17,000 and approximately 20,000) and the Truven MarketScan outpatient and databases (approximately 87 million) patients. We used International Classification of Diseases, 9th Revision codes to identify AMD diagnoses and L-DOPA prescriptions to determine the relative risk of developing AMD and age of onset with or without an L-DOPA prescription.

RESULTS

In the retrospective analysis of patients without an L-DOPA prescription, AMD age of onset was 71.2, 71.3, and 71.3 in 3 independent retrospective cohorts. Age-related macular degeneration occurred significantly later in patients with an L-DOPA prescription, 79.4 in all cohorts. The odds ratio of developing AMD was also significantly negatively correlated by L-DOPA (odds ratio 0.78; confidence interval, 0.76-0.80; P <.001). Similar results were observed for neovascular AMD (P <.001).

CONCLUSIONS

Exogenous L-DOPA was protective against AMD. L-DOPA is normally produced in pigmented tissues, such as the retinal pigment epithelium, as a byproduct of melanin synthesis by tyrosinase. GPR143 is the only known L-DOPA receptor; it is therefore plausible that GPR143 may be a fruitful target to combat this devastating disease.

Severe Ocular Inflammation Following Ranibizumab or Aflibercept Injections for Age-Related Macular Degeneration: A Retrospective Claims Database Analysis

Purpose: Intravitreal injections of anti-vascular endothelial growth factor (VEGF) agents including ranibizumab and aflibercept are used to treat patients with ocular disorders such as neovascular age-related macular degeneration (nAMD); however, the injections are associated with rare instances of severe ocular inflammation. This study compared severe ocular inflammation rates in patients treated with ranibizumab versus aflibercept.

Methods: United States physician-level claims data covering an 18-month period for each therapy were analyzed. The primary analysis compared severe ocular inflammation event rates per 1000 injections. Sensitivity and subgroup analyses evaluated the impact of factors including intraocular surgery, intravitreal antibiotic administration, and previous intravitreal injections.

Results: The analysis included 432,794 injection claims (ranibizumab n = 253,647, aflibercept n = 179,147); significantly, more unique severe ocular inflammation events occurred in patients receiving aflibercept than ranibizumab (1.06/1000 injections, 95% confidence interval [CI], 0.91–1.21, vs. 0.64/1000 injections, 95% CI 0.54–0.74; p < 0.0001). Comparable results were observed for analyses of patients who had undergone glaucoma or cataract surgeries, had antibiotic-associated endophthalmitis, had non-antibiotic-associated endophthalmitis, and were non-treatment-naive. In contrast, no significant differences in severe ocular inflammation claims were recorded in treatment-naive patients who had no record of anti-VEGF treatment in the 6 months preceding the index claim. No significant change occurred in the rate of severe ocular inflammation claims over time following ranibizumab treatment.

Conclusions: Severe ocular inflammation was more frequent following intravitreal injection with aflibercept than with ranibizumab during routine clinical use in patients with nAMD. This highlights the importance of real-world, post-approval, observational monitoring of novel medicines, and may aid clinical decision-making, including choice of anti-VEGF agent.