Posterior vitreous detachment with microplasmin alters the retinal penetration of intravitreal bevacizumab (Avastin) in rabbit eyes

Based on the Real-Life Data of Türkiye; Comparison of Anatomical and Functional Outcomes of Phakic and Pseudophakic Patients in Wet Type Age-Related Macular Degeneration

Objectives

The aim of the study was comparison of wet-type age-related macular degeneration in phakic and pseudophakic patients in terms of anatomical and functional success based on the real-life data of Türkiye.

Methods

The multicenter retrospective real-life study data of the. retinal study group were used in this study. Among 867 eyes of 867 patients were included in the study. Patients were divided into two groups according to the status of the lens; phakic group and pseudophakic group. The follow-up period of the two groups, the number of injections at the 1st, 2nd, and 3rd years, and changes in the central macular thickness (CMT, μ) and visual acuity (VA, logMAR) of the patients at the beginning, 6th, 12th, 24th, and 36th months were examined.

Results

In our study, the number of injections in the 1st, 2nd, and 3rd years, respectively, was 4.2±2.0, 1.8±1.9, and 1.0±1.7 in the phakic group, and 3.9±2.0, 1.7±1.9, and 0.8±1.4 in the pseudophakic group. When the two groups were compared in terms of the number of injections, there was a statistically significant difference in the 1st year, but there was no significant difference in the 2nd and 3rd years (p=0.001, p=0.350, and p=0.288, respectively). There was no statistically significant difference between the groups in terms of CMT in the baseline, 6th, 12th, 24th, and 36th months (p=0.991, p=0.327, p=0.652, p=0.599, and p=0.873, respectively). Although there was no difference in VA between groups at the beginning (p=0.052), the phakic group showed statistically better VA in controls at 3rd, 6th, 12th, 24th, and 36th months (p=0.001, p=0.001, p=0.000, p=0.000, and p=0.003, respectively).

Conclusion

Differences in the number of injections and visual results between phakic and pseudophakic patients in wet type AMD may necessitate the creation of different treatment and follow-up protocols.

A novel recombinant human microplasminogen induced complete posterior vitreous detachment without morphological change of retina in juvenile rabbits

Vitreomacular traction syndrome results from persistent vitreoretinal adhesions in the setting of partial posterior vitreous detachment (PVD). Vitrectomy and reattachment of retina is an effective therapeutic approach. The adhesion between vitreous cortex and internal limiting membrane (ILM) of the retina is stronger in youth, which brings difficulties to induce PVD in vitrectomy. Several clinical investigations demonstrated that intravitreous injection of plasmin before vitrectomy could reduce the risk of detachment. In our study, a novel recombinant human microplasminogen (rhμPlg) was expressed by Pichia pastoris. Molecular docking showed that the binding of rhμPlg with tissue plasminogen activator (t-PA) was similar to plasminogen, suggesting rh μPlg could be activated by t-PA to generate microplasmin (μPlm). Moreover, rhμPlg had higher catalytic activity than plasminogen in amidolytic assays. Complete PVD was found at vitreous posterior pole of 125 μg rhμPlg-treated eyes without morphological change of retina in juvenile rabbits via intraocular injection. Our results demonstrate that rhμPlg has a potential value in the treatment of vitreoretinopathy.

Morphology and Composition of the Inner Limiting Membrane: Species-Specific Variations and Relevance toward Drug Delivery Research

The inner limiting membrane (ILM) represents the structural boundary between the vitreous and the retina, and is suggested to act as a barrier for a wide range of retinal therapies. While it is widely acknowledged that the morphology of the human ILM exhibits regional variations and undergoes age-related changes, insight into its structure in laboratory animals is very limited. Besides presenting a detailed overview of the morphology and composition of the human ILM, this review specifically reflects on the species-specific differences in ILM structure. With these differences in mind, we furthermore summarize the most relevant reports on the barrier role of the ILM with regard to viral vectors, nanoparticles, anti-VEGF medication and stem cells. Overall, this review aims to deliberate on the impact of species-specific ILM variations on drug delivery research as well as to pinpoint knowledge gaps which future basic research should resolve.

The role of posterior vitreous detachment on the efficacy of anti-vascular endothelial growth factor intravitreal injection for treatment of neovascular age-related macular degeneration

Purpose:

A prospective cohort study investigating the effect of posterior vitreous detachment (PVD) on the efficacy of intravitreal bevacizumab for exudative age-related macular degeneration (AMD), in view of evidence that the vitreoretinal interface impacts the severity of the disease.

Methods:

Treatment-naïve AMD eyes with (+) complete PVD and without (−) PVD on ultrasonography received three monthly and then pro re nata bevacizumab injections. Best-corrected visual acuity (BCVA) on Snellen charts and optical coherence tomography (OCT) findings were recorded for 12 months. Secondary analysis included PVD definition and group allocation according to OCT baseline scan.

Results:

Forty-one eyes of 34 patients met the inclusion criteria. At 12 months, median BCVA improved by 0.12 logMAR in the PVD+ group [interquartile range (IQR) −0.52, 0.03, P = 0.140] and remained the same in the PVD− group (IQR −0.12, 0.15, P = 0.643). Median central retinal thickness improved by 43.5 μm and 43 μm in the PVD+ (IQR −143, 3, P = 0.016) and PVD− group (IQR −90, −14, P = 0.008), respectively. All parameters were similar in the two groups at final follow up (P > 0.05). The secondary analysis included 32 eyes of 26 patients and showed no significant differences between the groups at the 12 months endpoint (P > 0.05).

Conclusion:

Our findings show no significant impact of PVD as assessed by ultrasound or by OCT on visual and anatomical outcomes in exudative AMD treated with bevacizumab.

Ranibizumab Versus Bevacizumab for Neovascular Age-Related Macular Degeneration With an Incomplete Posterior Vitreous Detachment

PURPOSE

The aim of this study was to compare the effects of ranibizumab to those of bevacizumab during the treatment of neovascular age-related macular degeneration (AMD) with an incomplete posterior vitreous detachment.

DESIGN

A retrospective chart review.

METHODS

A retrospective chart review was performed on treatment-naive neovascular AMD subjects with an incomplete posterior vitreous detachment treated with either ranibizumab or bevacizumab over a 12-month period.

RESULTS

One hundred thirty subjects were analyzed. There were 49 subjects determined to have vitreous attachment to the fovea. Subjects with vitreous attachment to the fovea required a significantly greater number of injections during the study interval compared with those without (10.2 ± 0.75 vs 7.8 ± 0.62) (P < 0.0001). In subjects with vitreous attachment to the fovea, the ranibizumab cohort had a greater improvement in visual acuity (0.18 ± 0.1 vs 0.04 ± 0.11 logMAR) (P = 0.0176) and a greater reduction in macular thickness (93.4 ± 32.2 μm vs 30.3 ± 28.3 μm) (P = 0.0064) compared with the bevacizumab cohort.

CONCLUSIONS

Neovascular AMD patients with vitreous attachment to the fovea may have better visual and anatomic outcomes when treated with ranibizumab compared with bevacizumab.

Comparison of intravitreal ranibizumab between phakic and pseudophakic neovascular age-related macular degeneration patients: Two-year results

Background and objective

To compare the efficacy of intravitreal ranibizumab (IVR) for the treatment of neovascular age-related macular degeneration (nAMD) between phakic and pseudophakic eyes after a follow-up of two years.

Materials and methods

Data were analyzed retrospectively. The newly diagnosed and treatment naïve nAMD patients were included in the study. The patients were divided into two subgroups: phakic group, and pseudophakic. All patients received 3 consecutive monthly IVR injections, and then the treatment was continued on an as-needed regimen. Patients were examined monthly, and the data at the baseline, at month 6, 12, 18, and 24 were evaluated. The changes in best corrected visual acuity (BCVA), central retinal thickness (CRT), and the number of injections were compared between the two groups.

Results

The study included 92 eyes of 87 patients (58 phakic, 34 pseudophakic). Mean logarithm of the minimal angle of resolution (LogMAR) VA at the baseline, and at month 6, 12, 18, and 24 was 0.89, 0.74, 0.75, 0.73, and 0.75, in the phakic group; and 0.79, 0.71, 0.66, 0.70, and 0.70 in the pseudophakic group, respectively. The change in mean BCVA from the baseline to month 6, 12, 18, and 24 was not statistically different between the two groups (p = 0.4, p = 0.9, p = 0.5, p = 0.6, respectively). Mean injection number at month 24 was 7.9 and 8.1 in the phakic and pseudophakic group, respectively (p = 0.7).

Conclusion

Intravitreal ranibizumab treatment on an as-needed treatment regimen is effective in preserving vision and improving central retinal thickness in both the phakic and pseudophakic group of nAMD patients. The functional and anatomical outcomes of the treatment, and the number of injections were similar in the phakic and pseudophakic nAMD patients after a follow-up time of 24 months.

[The role of the vitreous body in diseases of neighboring structures]

BACKGROUND

The vitreoretinal interface is not merely the space between the vitreous body and the retina but it is also a site for highly complex pathologies with the vitreous body exerting an influence on all the neighbouring structures.

METHODS

A literature search was performed in Pubmed and current book articles

RESULTS

This review article highlights the role of the vitreous body in vitreomacular adhesion and traction, in the development of macular holes and epiretinal membranes as well as its role in age-related macular degeneration. In the retinal periphery the vitreous structures play a pivotal role in retinal tears and detachment as well as in diabetic and other proliferative vitreoretinopathies. The role of the vitreous bodyin the emergence of various forms of cataract is often underestimated.

DISCUSSION

Vitreo-etinal surgeons should thoroughly understand the pathophysiological relationship between the vitreous body and the neighboring structures, especially in the era of medical vitreolysis.

Effect of aflibercept in patients with age-related macular degeneration

The purpose of this study was to evaluate the efficacy of standard induction therapy with intravitreal aflibercept (IVA) in patients with exudative age-related macular degeneration (AMD) at 6 months after completion of induction therapy. Eleven eyes with typical AMD (tAMD) and 13 eyes with polypoidal choroidal vasculopathy (PCV) received three monthly doses of IVA (2 mg/0.05 ml in weeks 0, 4, and 8) for treatment of exudative AMD. Best-corrected visual acuity (BCVA) was measured, and optical coherence tomography was performed at baseline and at each monthly visit until 6 months after IVA. Treatment failure was defined as persistent or recurrent AMD that presented with cystoid macular edema, serous retinal detachment, and pigment epithelium detachment. Mean logMAR BCVA was improved from 0.62 ± 0.46 at baseline to 0.54 ± 0.43 at 6 months after IVA (p < 0.05). The success rate was 95.8 % at 3 months and 75.0 % at 6 months after IVA. Failure of IVA was positively associated with the absence of PVD before treatment (r = 0.35) and with the AMD type (tAMD, r = 0.43) by univariate analysis. Cox proportional hazards analysis demonstrated that the absence of PVD before treatment was associated with an increased risk of failure of IVA (OR = 33.17, p = 0.0219). Three months of induction IVA achieved a high success rate in patients with AMD monitored for up to 6 months. Factors associated with failure of IVA were the absence of PVD and the presence of tAMD. Accordingly, continuation of IVA following induction therapy may be beneficial to manage AMD in patients with tAMD or those without PVD.

Treat-and-extend bevacizumab for neovascular age-related macular degeneration: the importance of baseline characteristics

PURPOSE

To evaluate the factors affecting visual and anatomical outcomes and the number of intravitreal bevacizumab injections required in the treatment of neovascular age-related macular degeneration using a treat-and-extend regimen.

METHODS

Retrospective consecutive case series. The charts of subjects treated with intravitreal bevacizumab for neovascular age-related macular degeneration using a treat-and-extend regimen over a 12-month period were reviewed. The key variables explored were patient age, phakic status, posterior vitreous detachment status, baseline best-corrected visual acuity (BCVA), baseline central macular thickness (CMT), and type of chorodial neovascularization. The primary outcome measures were improvement in BCVA of 3 logMAR lines or more, maintenance of BCVA within 3 logMAR lines of baseline, number of intravitreal injections delivered over a 12-month period, and final CMT on optical coherence tomography.

RESULTS

A total of 230 eyes met the criteria. Mean presenting BCVA was Snellen 20/55 (0.44 logMAR) and mean final BCVA was Snellen 20/44 (0.35 logMAR) (P < 0.001). A total of 23.5% (95% confidence interval [CI], 18.5-29.4%) of the subjects demonstrated an improvement in BCVA of 3 or more logMAR lines, whereas 96.5% (95% CI, 93.3-98.2%) of the subjects lost fewer than 3 logMAR lines. Mean CMT on optical coherence tomography changed from a baseline average of 373.1 μm (95%CI, 360.3-386.1 μm) to a final average of 305.5 μm (95% CI, 290.0-316.0 μm). The average number of injections during the 12-month period was 9.2 (95% CI, 9.0-9.4). Posterior vitreous detachment was associated with fewer injections on univariate and multivariate analysis (8.7 injections in the posterior vitreous detachment group versus 9.8 in the non-posterior vitreous detachment group, P < 0.001). Patients with poorer presenting BCVA and greater baseline CMTs were more likely to demonstrate a 3 or more logMAR line improvement in BCVA. Thinner final CMTs were independently associated with thinner presenting CMTs and fewer injections.

CONCLUSION

Favorable visual and anatomical outcomes may be achieved with intravitreal bevacizumab in the treatment of neovascular age-related macular degeneration using a treat-and-extend regimen. Our study suggests that posterior vitreous detachment may play a role in the efficacy of intravitreal bevacizumab during the treatment of neovascular age-related macular degeneration.

Intravitreal drug delivery in retinal disease: are we out of our depth?

INTRODUCTION

With the ever-increasing global burden of retinal disease, there is an urgent need to vastly improve formulation strategies that enhance posterior eye delivery of therapeutics. Despite intravitreal administration having demonstrated notable superiority over other routes in enhancing retinal drug availability, there still exist various significant physical/biochemical barriers preventing optimal drug delivery into the retina. A further complication lies with an inability to reliably translate laboratory-based retinal models into a clinical setting. Several formulation approaches have recently been evaluated to improve intravitreal therapeutic outcomes, and our aim in this review is to highlight strategies that hold the most promise.

AREAS COVERED

We discuss the complex barriers faced by the intravitreal route and examine how formulation strategies including implants, nanoparticulate carriers, viral vectors and sonotherapy have been utilized to attain both sustained delivery and enhanced penetration through to the retina. We conclude by highlighting the advances and limitations of current in vitro, ex vivo and in vivo retinal models in use by researchers globally.

EXPERT OPINION

Various nanoparticle compositions have demonstrated the ability to overcome the retinal barriers successfully; however, their utility is limited to the laboratory setting. Optimization of these formulations and the development of more robust experimental retinal models are necessary to translate success in the laboratory into clinically efficacious outcomes.

Ocriplasmin for symptomatic vitreomacular adhesion: an evidence-based review of its potential

Vitreomacular traction is a multicategory entity that may cause substantial visual loss due to the formation of a macular hole or traction-induced tissue distortion. The advent of optical coherent tomography (OCT) has demonstrated the anatomic features of persistent vitreomacular attachment (VMA) more definitively, including in many asymptomatic or minimally symptomatic patients. The indications for intervention are unclear, since it is not possible to predict which eyes might be likely to develop progressive visual loss. This has been especially important since for many years, the only treatment option involved surgical intervention (vitrectomy) to release the persistent VMA. Recently, a pharmacolytic agent, ocriplasmin, has become available after many years of development and investigation, and may offer a feasible alternative to surgery, or even a risk/benefit ratio sufficiently favorable to offer intervention at an earlier stage of VMA. Several studies, including a large, prospective clinical trial, have established the foundation of its rationale and efficacy, providing the basis of its approval. The role for ocriplasmin in clinical practice is in the process of being determined. This paper summarizes current knowledge and status of investigations regarding ocriplasmin-induced pharmacologic vitreolysis, and offers some evidence-based considerations for its use.

Anatomic and pharmacokinetic properties of intravitreal bevacizumab and ranibizumab after vitrectomy and lensectomy

PURPOSE

To determine the anatomic characteristics and pharmacokinetic properties of intravitreally placed bevacizumab and ranibizumab after pars plana lensectomy or pars plana vitrectomy and to compare these with nonoperated control eyes in a rabbit model.

METHODS

Three groups of six Dutch-belted rabbits each underwent pars plana vitrectomy, pars plana lensectomy, or served as nonsurgical controls. Twelve days after surgery, 3 rabbits from each group underwent intravitreal injection in one eye with 1.25 mg/0.05 mL I-124-bevacizumab or 0.5 mg/0.05 mL I-124-ranibizumab. Serial imaging with integrated positron emission and computed tomography (PET/CT) were obtained on Days 0, 2, 5, 7, 14, 21, 28, and 35. Measured radioactivity emission in becquerels/milliliter was used to calculate the half-lives for each agent.

RESULTS

The intravitreally placed radiolabeled agents were contained within the vitreous cavity for the duration of the study. The average clearance half-lives with standard error for bevacizumab and ranibizumab after correction for radioactive decay were, respectively, 4.22 ± 0.07 days and 2.81 ± 0.05 days in unoperated eyes, 2.30 ± 0.09 days (P < 0.0001) and 2.13 ± 0.05 days (P < 0.0001) after vitrectomy, and 2.08 ± 0.07 days (P = 0.0001) and 1.79 ± 0.05 days (P < 0.0001) after lensectomy.

CONCLUSION

Intravitreal retention was longer for bevacizumab than ranibizumab within all study groups and was significantly reduced after vitrectomy and lensectomy for both agents. Consideration for more frequent intravitreal anti-vascular endothelial growth factor dosing regimens may be made for patients whose treated eyes have undergone previous vitrectomy or who are aphakic.

Ocriplasmin for vitreoretinal diseases

Fibronectin and laminin are clinically relevant plasmin receptors in the eye. Located at the vitreoretinal interface, they are cleaved by ocriplasmin (Microplasmin, ThromboGenics, Iselin, NJ), a novel ophthalmic medication. A series of clinical trials to study ocriplasmin for the treatment of vitreoretinal diseases such as vitreomacular traction, macular hole, and exudative age-related macular degeneration are underway. The results are promising and may impact patient care.

Three treatments for macular edema because of branch retinal vein occlusion: intravitreous bevacizumab or tissue plasminogen activator, and vitrectomy

PURPOSE

To evaluate the effectiveness of intravitreous bevacizumab (Avastin), intravitreous tissue plasminogen activator, and vitrectomy for the macular edema secondary to branch retinal vein occlusion.

METHODS

Retrospective, interventional case series. We studied 228 eyes of 228 patients. Forty-one eyes received 1.25 mg of intravitreous bevacizumab, 71 eyes received tissue plasminogen activator, and 116 eyes underwent vitrectomy. A reinjection of 1.25 mg of bevacizumab was based on the morphologic and functional findings. The main outcome measures were the best-corrected visual acuity and optical coherence tomography-determined foveal thickness.

RESULTS

The mean postoperative follow-up period was 32.2 months with a range of 12 months to 69 months. The mean number of intravitreous bevacizumab was 2.8 with a range of 1 to 5. The mean best-corrected visual acuity and foveal thickness significantly improved after all 3 treatments, and the differences in the best-corrected visual acuity between the 3 groups were not significant at 12 months. Fourteen eyes (34%) in the intravitreous bevacizumab group and 21 eyes (30%) in the tissue plasminogen activator group required additional surgeries.

CONCLUSION

The 3 treatments appear to provide similar visual outcomes at 12 months. However, in some eyes treated with intravitreous bevacizumab or tissue plasminogen activator, additional surgeries were required, and a longer follow-up period was required to determine the final outcome.