PERMEABILITY AND ANTI–VASCULAR ENDOTHELIAL GROWTH FACTOR EFFECTS OF BEVACIZUMAB, RANIBIZUMAB, AND AFLIBERCEPT IN POLARIZED RETINAL PIGMENT EPITHELIAL LAYER IN VITRO

A First-Passage Model of Intravitreal Drug Delivery and Residence Time-Influence of Ocular Geometry, Individual Variability, and Injection Location

Purpose

Standard of care for various retinal diseases involves recurrent intravitreal injections. This motivates mathematical modeling efforts to identify influential factors for ocular drug residence time, aiming to minimize administration frequency. We sought to describe the vitreal diffusion of therapeutics in nonclinical species frequently used during drug development assessments. In human eyes, we investigated the impact of variability in vitreous cavity size and eccentricity, and in injection location, on drug disposition.

Methods

Using a first-passage time approach, we modeled the transport-controlled distribution of two standard therapeutic protein formats (Fab and IgG) and elimination through anterior and posterior pathways. Anatomical three-dimensional geometries of mouse, rat, rabbit, cynomolgus monkey, and human eyes were constructed using ocular images and biometry datasets. A scaling relationship was derived for comparison with experimental ocular half-lives.

Results

Model simulations revealed a dependence of residence time on ocular size and injection location. Delivery to the posterior vitreous resulted in increased vitreal half-life and retinal permeation. Interindividual variability in human eyes had a significant influence on residence time (half-life range of 5-7 days), showing a strong correlation to axial length and vitreal volume. Anterior exit was the predominant route of drug elimination. Contribution of the posterior pathway displayed a 3% difference between protein formats but varied between species (10%-30%).

Conclusions

The modeling results suggest that experimental variability in ocular half-life is partially attributed to anatomical differences and injection site location. Simulations further suggest a potential role of the posterior pathway permeability in determining species differences in ocular pharmacokinetics.

Recent advances and future prospects: current status and challenges of the intraocular injection of drugs for vitreoretinal diseases

Effective drug therapy for vitreoretinal disease is a major challenge in the field of ophthalmology; various protective systems, including anatomical and physiological barriers, complicate drug delivery to precise targets. However, as the eye is a closed cavity, it is an ideal target for local administration. Various types of drug delivery systems have been investigated that take advantage of this aspect of the eye, enhancing ocular permeability and optimizing local drug concentrations. Many drugs, mainly anti-VEGF drugs, have been evaluated in clinical trials and have provided clinical benefit to many patients. In the near future, innovative drug delivery systems will be developed to avoid frequent intravitreal administration of drugs and maintain effective drug concentrations for a long period of time. Here, we review the published literature on various drugs and administration routes and current clinical applications. Recent advances in drug delivery systems are discussed along with future prospects.

Difference in Lesion Reactivation between Pure Type 2 and Mixed Type 1 and 2 Macular Neovascularization and its Influence on Long-Term Treatment Outcomes

PURPOSE

To compare lesion reactivation and treatment outcomes between pure type 2 and mixed type 1 and 2 macular neovascularization (MNV) treated with anti-vascular endothelial growth factor (VEGF).

METHODS

This retrospective study included 155 patients diagnosed with type 2 MNV. After the initial loading injections, as-needed retreatment was provided. The difference in first lesion reactivation after the initial treatment was evaluated between pure type 2 MNV (pure type 2 group, n = 37) and mixed type 1 and 2 MNV (mixed group, n = 118). The degree of change in the best-corrected visual acuity (BCVA) was also compared between the two groups.

RESULTS

The mean follow-up period was 32.7 ± 13.7 months. Lesion reactivation differed significantly between the type 2 (60.0%) and mixed (84.5%) (P = .004) groups. The degree of visual change during the follow-up period also differed significantly between the pure type 2 (mean 2.8 lines of improvement) and mixed (mean 0.2 lines of deterioration) (P = .008) groups. In multivariate analysis, lesion type (P = .012) and baseline visual acuity (P = .002) were significantly associated with ≥2 lines of visual improvement.

CONCLUSIONS

Lesion reactivation and treatment outcomes differed between pure type 2 and mixed type 1 and 2 MNV. These results suggested the need for different treatment strategies for these two MNV subtypes.

Brolucizumab Intravitreal Injection in Macular Neovascularization Type 1: VA, SD-OCT, and OCTA Parameter Changes during a 16-Week Follow-Up

INTRODUCTION

The aim of this study was to assess early anatomical and functional changes after brolucizumab intravitreal injection (BIVI) in patients with age-related macular degeneration (AMD) and macular neovascularization type 1 (MNV1).

METHODS

A total of 24 eyes of 24 patients suffering from naïve AMD with MNV1 candidates to BIVI as per label with q12/q8 dosing regimen after the loading dose were enrolled in this prospective study. Main outcome measures during a 16-week follow-up period included changes in best corrected visual acuity (BCVA), central macular thickness (CMT), subfoveal subretinal fluid (SSRF) thickness (SSRFT), subfoveal sub-retinal pigment epithelium (RPE) fluid thickness (SSRPEFT), subfoveal choroidal thickness (SFCT), and pigment epithelial detachment (PED) maximum height (PED-MH). In addition, MNV1 flow area; percentages of eyes with intraretinal fluid (IRF), subretinal fluid, and sub-RPE fluid at different time points; and percentages of eyes candidates to a q8 or q12 injection interval after disease activity assessment at week 16 were evaluated.

RESULTS

BCVA improved significantly from baseline (T0) to week 12 (T3) (p = 0.028). CMT showed a significant reduction from 456 ± 123 µm at T0 to 265 ± 85 µm at T3 (p < 0.001). SSRFT and SSRPEFT reduced significantly as well (p < 0.001 and p = 0.049, respectively). PED-MH and SFCT reduced significantly at the different time points (p = 0.020; p = 0.006, respectively). IRF presence changed significantly from 41.7% of eyes at T0 to 20.8% at T3 (p = 0.045). SSRF reduced significantly during follow-up, being present in 62.5% of eyes at T0 and 4.2% of eyes at T3 (p < 0.001). Subfoveal sub-RPE fluid decreased significantly during time, being present in 20.8% of eyes at T0 and 0% at T3 (p = 0.013). Most of the eyes (18 eyes, 75%) at week 16 after disease activity assessment were shifted in the q12 interval, and only a minority of eyes shifted in a q8 interval (6 eyes, 25%).

CONCLUSION

Brolucizumab is efficient in AMD patients with MNV1 by reducing all retinal fluids during the loading phase and shows reduction of macular thickness, choroidal thickness, and PED height. Most eyes at disease activity assessment (75%) fall into 12-week interval and the minority (25%) into the 8-week interval.

Short-term outcomes of intravitreal brolucizumab for treatment-naïve neovascular age-related macular degeneration with type 1 choroidal neovascularization including polypoidal choroidal vasculopathy

We evaluated the efficacy and safety of loading phase treatment with intravitreal brolucizumab for neovascular age-related macular degeneration (nAMD) with type 1 choroidal neovascularization (CNV). We analyzed consecutive 42 eyes of 40 patients with treatment-naïve nAMD associated with type 1 CNV. Three monthly injections of brolucizumab were completed in 36 eyes (85.7%). In those cases, best-corrected visual acuity (BCVA) was 0.24 ± 0.27 at baseline and improved significantly to 0.12 ± 0.23 after 3 months (P < 0.001). Central macular thickness was 301 ± 110 µm at baseline and decreased significantly to 160 ± 49 µm after 3 months (P < 0.001). Dry macula was achieved in 34 eyes (94.4%) after the loading phase. Central choroidal thickness was 264 ± 89 µm at baseline and decreased significantly to 223 ± 81 µm after 3 months (P < 0.001). Indocyanine green angiography after the loading phase revealed complete regression of polypoidal lesions in 15 of the 19 eyes (78.9%) with polypoidal lesions. Non-infectious intraocular inflammation (IOI) was observed in 8 of 42 eyes (19.0%) during the loading phase, while showing amelioration in response to combination therapy with topical and subtenon injection of steroids. In these eyes, BCVA after 3 months had not deteriorated as compared to that at baseline. These results indicate that loading phase treatment with intravitreal brolucizumab might be effective for improving visual acuity and reducing exudative changes in eyes with nAMD associated with type 1 CNV. Moreover, polypoidal lesions appear to frequently regress after this treatment. However, we must monitor patients carefully for brolucizumab-related IOI, and administer steroid therapy promptly.

Effects of ranibizumab (Lucentis®) and bevacizumab (Avastin®) on human corneal endothelial cells

Background

Ingrowth of newly formed blood and lymph vessels (angiogenesis) from the limbus region into the cornea can be treated successfully by subconjunctival application of antiangiogenic agents. Currently, there are several angiogenesis inhibitors from various manufacturers available, such as vascular endothelial growth factor (VEGF) antibodies. The aim of the study was to investigate potential cytotoxic effects of two anti-VEGF agents, ranibizumab (Lucentis®) and bevacizumab (Avastin®) on the human corneal endothelium.

Methods

Human donor corneas, not suitable for corneal transplantation, were organ-cultured in the presence of either ranibizumab (Lucentis®) or bevacizumab (Avastin®) at different concentrations (group 1: 250 μg / ml, group 2: 25 μg / ml, group 3: 2.5 μg / ml) for a period of up to 4 weeks. Microscopic imaging for endothelial cell counting, detection of morphologic alterations of the endothelium, and molecular biology testing (Enzyme-linked Immunosorbent Assay [ELISA]) for metabolic changes was performed.

Results

Background-corrected results showed neither a significant lactate dehydrogenase (LDH) change with increasing culturing time nor a significant difference between ranibizumab (Lucentis®) and bevacizumab (Avastin®) treatment. The endothelial cell density revealed also no statistically significant difference between the two treatment groups with ranibizumab (Lucentis®) and bevacizumab (Avastin®) at all concentrations tested in this study.

Conclusions

In this study, the anti-angiogenic agents ranibizumab (Lucentis®) and bevacizumab (Avastin®) demonstrated no cytotoxic effects on the corneal endothelium of human organ-cultured donor corneas over the limited study time period of 4 weeks. However, based on the study design (in-vitro) and the limited follow-up period, no conclusions on potential long-term effects can be drawn.

Diagnosis and Treatment of Myopic Maculopathy

Visual impairment resulting from pathologic myopia is a serious issue worldwide. This is mainly due to the development of different types of myopic maculopathy. Despite being a major cause of visual impairment worldwide, myopic maculopathy was not consistently defined. To overcome this problem, in 2015 the Meta-Analysis for Pathologic Myopia Study Group proposed a simplified, uniform classification system for myopic maculopathy. Among several lesions of myopic maculopathy, myopic choroidal neovascularization (CNV) is one of the most common and severe vision-threatening complications. Recent large clinical trials have reported a good initial efficacy for visual acuity improvement by application of anti-vascular endothelial growth factor therapy for myopic CNVs. However, long-term clinical studies demonstrate a gradual decrease in the visual acuity gain and return to the baseline level due to the development of myopic CNV-related macular atrophy. Regarding visual impairment caused by advanced myopic chorioretinal atrophy, the only way to prevent blindness is to prevent myopia from developing or progressing at a young age before the axial length elongates extremely. As peripapillary diffuse atrophy in childhood may be an indicator of more advanced myopic chorioretinal atrophy in later life, some preventive measures should be considered in such children.

A Role for βA3/A1-Crystallin in Type 2 EMT of RPE Cells Occurring in Dry Age-Related Macular Degeneration

Purpose

The RPE cells have a major role in the development of dry age-related macular degeneration (AMD). We present novel evidence that βA3/A1-crystallin, encoded by the Cryba1 gene, a protein known to be important for lysosomal clearance in the RPE, also has a role in epithelial-to-mesenchymal transition (EMT) of RPE cells.

Methods

RPE from dry AMD globes, genetically engineered mice lacking Cryba1 globally or specifically in the RPE, spontaneous mutant rats (Nuc1) with a loss-of-function mutation in Cryba1, and the melanoma OCM3 cell line were used. Spatial localization of proteins was demonstrated with immunofluorescence, gene expression levels were determined by quantitative PCR (qPCR), and protein levels by Western blotting. Cell movement was evaluated using wound healing and cell migration assays. Co-immunoprecipitation was used to identify binding partners of βA3/A1-crystallin.

Results

βA3/A1-crystallin is upregulated in polarized RPE cells compared to undifferentiated cells. Loss of βA3/A1-crystallin in murine and human RPE cells resulted in upregulation of Snail and vimentin, downregulation of E-cadherin, and increased cell migration. βA3/A1-crystallin binds to cortactin, and loss of βA3/A1-crystallin resulted in increased P-cortactin^Y421. The RPE from AMD samples had increased Snail and vimentin, and decreased E-cadherin, compared to age-matched controls.

Conclusions

We introduced a novel concept of dry AMD initiation induced by lysosomal clearance defects in the RPE and subsequent attempts by RPE cells to avoid the resulting stress by undergoing EMT. We demonstrate that βA3/A1-crystallin is a potential therapeutic target for AMD through rejuvenation of lysosomal dysfunction and potentially, reversal of EMT.

Changes in systemic vascular endothelial growth factor levels after intravitreal injection of aflibercept in infants with retinopathy of prematurity

BACKGROUND

To investigate the levels of VEGF in the systemic circulation of patients with type 1 ROP who received intravitreal injections of 1 mg (0.025 mL) aflibercept (IVA) or 0.625 mg (0.025 mL) bevacizumab (IVB).

METHODS

Patients who had type 1 ROP and received either IVA or IVB were enrolled in this prospective study. Serum and plasma samples were collected prior to and up to 12 weeks after IVB or IVA treatment. The serum and plasma VEGF levels were measured using enzyme-linked immunosorbent assays (ELISAs), and the platelet levels in the blood were also quantified. The serum and plasma levels of VEGF, as well as the ratio of VEGF to platelet count (VEGF/PLT) were measured prior to and up to 12 weeks after anti-VEGF treatment.

RESULTS

In total, 14 patients with type 1 ROP were enrolled in this study; five patients received IVA, and nine patients received IVB. Following either IVA or IVB treatment, all the eyes (100%) showed complete resolution of ROP-induced abnormal neovascularization and presented continued vascularization toward the peripheral retina. Compared to baseline, the serum VEGF levels were significantly reduced in the ROP patients up to 12 weeks after either IVA or IVB treatments (all P < 0.05). At 2, 4, and 8 weeks after intravitreal injection, the serum VEGF levels were more suppressed in the IVB group than in the IVA group (P = 0.039, P = 0.004, and P = 0.003, respectively). The serum VEGF/PLT ratio after IVA or IVB showed similar reductions and trends as the serum VEGF data. Changes in the plasma VEGF levels could not be properly assessed because some of the samples had VEGF levels below the detection limit of the ELISA.

CONCLUSIONS

Serum VEGF levels and the VEGF/PLT ratio in patients with type 1 ROP were suppressed for 3 months after treatment with either IVA or IVB, but the suppression of systemic VEGF was more pronounced in patients treated with IVB than those treated with IVA.