Pharmaceutical compounding of aflibercept in prefilled syringes does not affect structural integrity, stability or VEGF and Fc binding properties

Pharmaceutical compounding and storage of faricimab in a syringe for intravitreal injection do not impair stability and bi-specific binding properties

BACKGROUND

Intravitreal injection (IVI) of antibody biologics is a key treatment approach in ophthalmology. Pharmaceutical compounding and storage of prefilled syringes for IVI must take place without impairing the structure and function of the biologics. This study investigated the effect of withdrawing and storing the therapeutic antibody faricimab (Vabysmo, Roche, Basel, Switzerland) in the Zero Residual silicone oil-free, 0.2-mL syringe (SJJ Solutions, The Hague, the Netherlands).

METHODS

To assess the effect of syringe withdrawal on faricimab, we compared samples from syringes prepared at day 0 with samples taken directly from faricimab vials. To assess the effect of syringe storage on faricimab, we kept prefilled syringes in the dark at 4 oC for 7, 14, or 37 days and compared samples from these syringes with day 0. We measured protein concentration (with spectrophotometry), stability and integrity (with sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), size-exclusion chromatography (SEC), and melting temperature (Tm)), as well as binding of faricimab to its cognate antigens: vascular endothelial growth factor A (VEGF-A) and angiopoietin-2 (Ang-2) (with enzyme-linked immunosorbent assay (ELISA)).

RESULTS

Faricimab migrated in line with its expected molecular mass under both reducing and non-reducing conditions for all time points when analyzed with SDS-PAGE, without any sign of degradation products or aggregation. The SEC elution profiles were identical for all time points. There were slight variations in Tm for different time points compared to day 0 but without consistent relationship with storage time. ELISA did not detect differences in VEGF-A or Ang-2 binding between time points, and faricimab did not bind the neonatal Fc receptor.

CONCLUSIONS

Withdrawal and storage of faricimab in syringes for up to day 37 did not impair the structure and bi-specific binding properties of the therapeutic antibody.

Lentiviral delivered aflibercept OXB-203 for treatment of neovascular AMD

Neovascular age-related macular degeneration (nAMD) is a leading cause of blindness in the aging population, with vascular endothelial growth factor (VEGF) playing a key role. Treatment with recombinant anti-VEGFs is the current standard of care; however, it is only effective for 1-2 months at a time and requires re-administration. Gene therapy could pave the way for stable, long-term expression of therapeutic anti-VEGF with a single dose, reducing the frequency of treatment and potentially improving clinical outcomes. As such, we have developed OXB-203, a lentiviral-based gene therapy encoding the anti-VEGF protein aflibercept. Aflibercept derived from OXB-203 exhibited comparable in vitro binding characteristics to VEGF as recombinant aflibercept. Furthermore, its biological potency was demonstrated by the equivalent inhibition of VEGF-induced human umbilical vein endothelial cell (HUVEC) proliferation and tubule formation as recombinant aflibercept. In a rat choroidal neovascularization (CNV) model of nAMD, a single subretinal administration of OXB-203 reduced laser-induced CNV lesion areas analogous to an intravitreal bolus of recombinant aflibercept. Finally, in a head-to-head comparative study, aflibercept derived from OXB-203 was shown to be expressed at significantly higher levels in ocular tissues than from an AAV8-aflibercept vector following a single subretinal delivery to rats. These findings support the therapeutic potential of OXB-203 for the management of nAMD.

Overexpression of miR-32 in Chinese hamster ovary cells increases production of Fc-fusion protein

The demand for industrial genetically modified host cells were increased with the growth of the biopharmaceutical market. Numerous studies on improving host cell productivity have shown that altering host cell growth and viability through genetic engineering can increase recombinant protein production. During the last decades, it was demonstrated that overexpression or downregulation of some microRNAs in Chinese Hamster Ovary (CHO) cells as the host cell in biopharmaceutical manufacturing, can improve their productivity. The selection of microRNA targets has been based on their previously identified role in human cancers. MicroRNA-32 (miR-32), which is conserved between humans and hamsters (Crisetulus griseus), was shown to play a role in the regulation of cell proliferation and apoptosis in some human cancers. In this study, we investigated the effect of miR-32 overexpression on the productivity of CHO-VEGF-trap cells. Our results indicated that stable overexpression of miR-32 could dramatically increase the productivity of CHO cells by 1.8-fold. It also significantly increases cell viability, batch culture longevity, and cell growth. To achieve these results, following the construction of a single clone producing an Fc-fusion protein, we transfected cells with a pLexJRed-miR-32 plasmid to stably produce the microRNA and evaluate the impact of mir-32 overexpression on cell productivity, growth and viability in compare with scrambled control. Our findings highlight the application of miRNAs as engineering tools and indicated that miR-32 could be a target for engineering CHO cells to increase cell productivity.

Physicochemical and Biological Stability Assessment of SB11 (Ranibizumab Biosimilar) Under Ambient and In-Use Storage for Intravitreal Administration

INTRODUCTION

SB11 (Byooviz™) is a ranibizumab biosimilar that acts as a vascular endothelial growth factor (VEGF)-A inhibitor. Stability data for unopened SB11 vials at room temperature are limited and no data are available for SB11 withdrawn into syringes (in-use) for intravitreal administration.

METHODS

SB11 stability was assessed in two different settings: unopened vials stored at 30 ± 2 °C/65 ± 5% relative humidity (RH) for 2 months, and in-use SB11 withdrawn into syringes stored at 5 ± 3 °C for 98 days and then 25 ± 2 °C/60 ± 5% RH for 24 h. The product was stored in the absence of light, and the experimental design followed International Conference on Harmonization and European Medicines Agency requirements for stability evaluation of biological products. Analysis included visual appearance (color, clarity, and presence of visible particles), pH, protein concentration (A₂₈₀) and purity (size-exclusion high-pressure liquid chromatography, capillary electrophoresis-sodium dodecyl sulfate, imaged capillary isoelectric focusing), biological activity (VEGF binding and neutralization), and safety (sub-visible particulates).

RESULTS

Except for charge variants in unopened vials at room temperature after 1 month by US standards, all results met the stability acceptance criteria (US and EU) for both unopened vials and for in-use SB11. There were no major changes in terms of physicochemical stability, biological activity and sub-visible particulates.

CONCLUSION

SB11 was stable for longer periods and at higher temperatures than what is stated in the labels of the reference product (Lucentis) and SB11. The physicochemical properties, biological activity, and sub-visible particulates of SB11 in both tested settings (unopened vials at room temperature and in-use product withdrawn into syringes) were maintained under the described storage periods. This information can help to avoid unnecessary delays in patient treatment without any loss in quality and biological activity, lower the workload of health care providers and reduce costs associated with drug waste.

Healthcare expenditure of intravitreal anti-vascular endothelial growth factor inhibitors compared with dexamethasone implant for diabetic macular oedema

PURPOSE

The aim of this study was to estimate the 1-year costs associated with treating diabetic macular oedema (DME) patients using current intravitreal anti-vascular endothelial growth factor (anti-VEGF) biologics compared with the dexamethasone implant.

METHODS

We conducted a descriptive cost-evaluation analysis using data from Oslo University Hospital and literature to compare three different intravitreal drugs for DME: bevacizumab, aflibercept and dexamethasone. Stratification of patients into 'Naive' or 'Switch' group was based on treatment history. We estimated the costs from healthcare and 'extended' healthcare perspectives. Sensitivity analysis evaluated the impact of various parameters.

RESULTS

The average injections per patient per year for the Naive group (bevacizumab), Switch group (aflibercept) and dexamethasone were 9.5, 9.1 and 3.0 respectively. From a healthcare perspective, the 1-year costs for the Naive group were 15% lower (bevacizumab, €3619), and for the Switch group, 23% higher (aflibercept, €5226) compared with dexamethasone (€4252). The 'extended' healthcare perspective showed the cost per patient per year for bevacizumab remained nominally lower in the Naive group, while dexamethasone remained lower for the Switch group (€5116 for dexamethasone, compared to €4987 for bevacizumab and €6537 for aflibercept).

CONCLUSIONS

From a primary healthcare perspective, the dexamethasone as a first-line DME treatment may increase economic costs in settings where bevacizumab is used off-label. Treating resistant DMEwith dexamethasone may reduce the costs and treatment burden compared with switching to aflibercept.

A Silicone Oil-Free Syringe Tailored for Intravitreal Injection of Biologics

Intravitreal injections (IVI) of biologics targeting vascular endothelial growth factor (anti-VEGF) led to a paradigm shift in the management and prognosis of prevalent retinal conditions. Yet, IVI are typically performed with syringes that are neither developed nor approved for this purpose. Notably, syringes lubricated with silicone oil (SiO) are extensively used despite multiple reports showing that such syringes can cause deposition of SiO droplets in the vitreous body and patient discomfort. Thus, there is a need for SiO-free substitutes specifically tailored for IVI. Here, we report on the development and testing of such a syringe. This syringe has no dead volume, and its design allows for high-accuracy dosing. Also, it permits pharmaceutical compounding and storage of bevacizumab, ranibizumab, and aflibercept for up to 30 days without compromising their functional binding or transport properties. Finally, the new syringe demonstrated a favorable safety profile regarding release of SiO compared to SiO lubricated alternatives, including commercially prefilled syringes. Accordingly, the newly developed syringe is an appealing alternative for IVI.

The sterility, stability and efficacy of repackaged ziv-aflibercept for intravitreal administration

To evaluate the sterility, stability, and efficacy of repackaged ziv-aflibercept in 1-mL plastic tuberculin syringes for intravitreal injection after storage for up to 90 days at controlled (4 °C) and ambient (25.8 °C) temperature. A total of 168 tuberculin-type 1-mL syringes were prepared containing ziv-aflibercept (100 mg/4 mL). Samples were stored at 4 °C and 25.8 °C for 0, 3, 7, 14, 21, 28, 60, and 90 days. At each time point, four samples were evaluated for the stability and binding affinity of anti-VEGF to VEGF (efficacy) using enzyme-linked immunosorbent assays (ELISAs). All samples were analyzed for microbial growth. No microbial growth was obtained from any of the ziv-aflibercept samples during each time point, indicating that the repackaged ziv-aflibercept stored at 4 °C and 25.8 °C remained sterile. ELISA analysis revealed no significant decrease in concentration, and binding affinity was observed, indicating that the stability and efficacy were preserved. However, the concentration of ziv-aflibercept decreased less than the minimum expected concentration of 8 ng/mL after 60 days at 4 °C and after 30 days at 25.8 °C. The repackaged anti-VEGF drug ziv-aflibercept does not lose stability or efficacy and remains uncontaminated if prepared under sterile conditions and stored at 4 °C for up to 60 days or stored at 25.8 °C for up to 30 days.

Impact of the COVID-19 pandemic on patients receiving intravitreal injections

We analyzed the economic benefits versus safety risks of sharing anti-vascular endothelial growth factor (VEGF) vials during the coronavirus disease (COVID-19) pandemic. This single-center retrospective study analyzed the data of patients with neovascular age-related macular degeneration (nAMD), proliferative diabetic retinopathy (PDR) and retinal vein occlusion (RVO) who received anti- VEGF between January 2016 and July 2021 at Renmin Hospital, Wuhan University, China. Costs were compared of the two protocols of intravitreal injections (IVIs) of ranibizumab, aflibercept and conbercept after (i) splitting the vial content for use in two patients and after (ii) disposal of the remaining vial content after use in a single patient, with the COVID-19 outbreak considered as the demarcation point. The incidence rates of post-injection endophthalmitis (PIE) pre- and post-outbreak were analyzed. The mean cost of a single IVI increased by 33.3%, from 3917.67?71.69 to 5222.67?84.98 Chinese Yuan during the pandemic. The incidences of IVI-related culture-positive PIE were 0.0134% (3 in 22448) and 0.0223% (1 in 4479), respectively, before and after the pandemic (P=0.6532). We conclude that vial sharing of IVIs in a large clinical institution is not associated with increased PIE risk and can significantly reduce the cost of therapy.

Cluster of symptomatic silicone oil droplets following intravitreal injections: a 1-year observational study

Objective

To describe a cluster of symptomatic intravitreal silicone oil (SiO) droplets following intravitreal injections (IVIs) and assess the effect of switching to a SiO-free syringe.

Methods and analysis

Observational quality registry study of patients receiving IVI at a large Norwegian ophthalmology centre between April 2018 (start of cluster) and November 2019 (1 year after switching to SiO-free syringes). At onset, anti-vascular endothelial growth factor drugs were administered using SiO-containing insulin syringes. From November 2018, SiO-free syringes were implemented. Spontaneously reported symptomatic SiO cases were confirmed by slit-lamp examination. A follow-up interview was performed after 1 year, assessing visual complaints. The prevalence of non-symptomatic cases was assessed in a sample of 50 eyes from 50 consecutive IVI patients.

Results

Among 13 429 IVIs, 50 eyes of 46 patients (29 women) with symptomatic intravitreal SiO droplets were identified. Forty-one patients reported floaters at regular appointments, whereas five patients contacted the department regarding symptoms between scheduled appointments. After 1 year, 34 patients (79%) still experienced floaters, 21 (49%) reported reduced symptoms and 3 (7%) reported worsened symptoms. Eighteen patients (42%) reported being bothered, and eight (18.6%) reported that their lives were negatively affected by the floaters. Among 50 non-symptomatic eyes that had received IVI during the same period, intravitreal SiO was found in 34 (68%). No cases of symptomatic intravitreal SiO droplets were identified after switching to SiO-free syringes.

Conclusion

Symptomatic intravitreal SiO following IVI can cause significant and prolonged distress for affected patients. It can be avoided by using SiO-free syringes.

Stability study over time of clinical solutions of ziv-aflibercept prepared in infusion bags using a proper combination of physicochemical and functional strategies

A range of biopharmaceutical products are used to target Vascular Endothelial Growth Factor (VEGF), including Eylea® (aflibercept, AFL) and Zaltrap® (ziv-aflibercept, ziv-AFL). The first is indicated for ophthalmological diseases such as neovascular (wet) age-related macular degeneration, while the second is used in the treatment of metastatic colorectal cancer. The stability of AFL in prefilled syringes has been widely studied; however, no research has yet been done on the stability of ziv-AFL in polyolefin infusion bags. Therefore, the purpose of the present research is to evaluate the stability of ziv-AFL (Zaltrap®) clinical solutions prepared under aseptic conditions in polyolefin infusion bags at two different concentrations, i.e. 4.0 and 0.6 mg/mL, and stored refrigerated in darkness at 2-8 °C for 14 days. With that aim, the ziv-AFL clinical solutions were assessed by analysing changes in its physicochemical and functional properties. The distribution of the particulates was studied over a range of 0.001-10 μm by Dynamic Light Scattering (DLS); oligomers were analysed by Size-Exclusion High-Performance Chromatography with Diode Array Detection (SE/HLPC-DAD); the secondary structure of the protein was studied by far UV Circular Dichroism (CD) and the tertiary structure by Intrinsic Tryptophan Fluorescence (IT-F) and Intrinsic Protein Fluorescence (IP-F); charge variants were assessed by Strong Cation Exchange Ultra-High-Performance Chromatography with UV detection (SCX/UHPLC-UV); functionality was evaluated by ELISA by measuring the biological activity as manifested in the extension of the immunological reaction of the ziv-AFL with its antigen (VEGF). Neither aggregation nor oligomerization were detected by the techniques mentioned above. Secondary and tertiary structures remained unchanged over the 14-day period, as did charge variants. The functionality observed initially was maintained along time. Therefore, it could be proposed that the ziv-AFL clinical solutions studied showed great physicochemical and functional stability over a period of two weeks, regardless of the concentration, i.e. 4 or 0.6 mg/mL.

Thirteen years of intravitreal anti-vascular endothelial growth factor therapy: the promises and burdens of a paradigm shift told from the perspective of the largest retina service in Norway

PURPOSE

To describe the first 13 years of anti-vascular endothelial growth factor (anti-VEGF) therapy from the perspective of a public ophthalmic department serving a local community of almost one million people.

METHODS

Retrospective registry study. Data from Oslo University Hospital, Norway were collected from 2006 through 2018. Hospital episode statistics were searched for episodes of care encompassing intravitreal anti-VEGF procedures. Patient-specific ID numbers, diagnoses, and drug codes were registered. In general, bevacizumab was used as first-line treatment, with aflibercept reserved for resistant cases from 2013.

RESULTS

The number of unique patients treated per year increased from 130 in 2006 to 3428 in 2018. In 2018, 2488 (73%) patients had also received treatment the previous year. The number of yearly injections increased from 228 in 2006 to 25 570 in 2018. In 2018 the diagnosis macular degeneration constituted 69% of injections, diabetic retinopathy constituted 15%, retinal vein occlusion constituted 13%, and other diagnoses constituted 3%. In the same year 49% of injections were with bevacizumab, 46% with aflibercept, 4% with ranibizumab, and 1% with dexamethasone implants. The bevacizumab to aflibercept ratio was almost 1:1 for macular degeneration and diabetic retinopathy; for retinal vein occlusion the ratio was 13:7.

CONCLUSION

In 13 years there was an approximately 100-fold increase in the number of yearly intravitreal injections. A majority of patients received long-term treatment. Macular degeneration was the most common diagnosis. Using bevacizumab as first-line treatment, with aflibercept reserved for resistant cases from 2013, eventually resulted in a nearly 1:1 ratio in drug usage.

COMPARATIVE RISK OF ENDOPHTHALMITIS AFTER INTRAVITREAL INJECTION WITH BEVACIZUMAB, AFLIBERCEPT, AND RANIBIZUMAB

PURPOSE

To determine whether sterile preloading of anti-vascular endothelial growth factor agents reduces the risk of postintravitreal injection endophthalmitis.

METHODS

This is a retrospective cohort study using medical claims data from a large, national US insurer. Cohorts were created using intravitreal injections of anti-vascular endothelial growth factor injections from 2005 to 2016. For inclusion, patients had to have at least 6 months of data before the injection and were excluded for any previous diagnosis of endophthalmitis, multiple injected drugs on the day of injection, or intraocular surgery within 15 days of the injection or between an injection and a diagnosis of endophthalmitis. The primary outcome was the odds of endophthalmitis after an intravitreal injection.

RESULTS

A total of 706,725 bevacizumab, 210,849 ranibizumab, and 177,731 aflibercept injections were given to 130,327 patients. Multivariate analysis showed that ranibizumab and aflibercept together had an increased odds of endophthalmitis (odds ratio = 1.29, 95% confidence interval: 1.04-1.59, P = 0.02) compared with bevacizumab. Individually, ranibizumab (odds ratio = 1.25, 95% confidence interval: 0.97-1.61, P = 0.08) and aflibercept (odds ratio = 1.34, 95% confidence interval: 0.99-1.81, P = 0.06) each had higher odds of endophthalmitis, but neither result met significance. Also, when compared with male patients, female patients had a higher odds of getting endophthalmitis (odds ratio: 1.30, 95% confidence interval: 1.05-1.61, P = 0.02).

CONCLUSION

The odds of endophthalmitis with aflibercept and ranibizumab combined were higher compared with the sterilely preloaded bevacizumab, arguing for a safety advantage of sterile preloading of anti-vascular endothelial growth factor injections.

Ziv-aflibercept: A cost-effective, off-label, highly potent antagonist of vascular endothelial growth factor

Ziv-aflibercept (Zaltrap^® ), a recombinant fusion protein that binds diffusible vascular endothelial growth factor (VEGF), is approved for the treatment of metastatic colorectal carcinoma. Its molecular structure is the same as aflibercept (Eylea^® ), thus making it an attractive option for the off-label treatment of chorioretinal vascular conditions. Ziv-aflibercept is distributed in 4 and 8 ml vials for intravenous use, and its cost after compounding is similar to bevacizumab. Studies with retinal pigment epithelium cytotoxicity, animal histologic sections and electroretinography have demonstrated its safety, and mathematical modelling combined with over four dozen clinical publications from different ophthalmic centres throughout the world attest to its efficacy. No appreciable differences in visual or anatomic outcomes between 1.25 mg (0.05 ml) and 2.5 mg (1.0 ml) doses have been noted. The long duration of action combined with the low cost make ziv-aflibercept an attractive anti-VEGF treatment option, especially in low- and middle-income countries where its popularity is increasing.

Comprehensive biophysical and functional study of ziv-aflibercept: characterization and forced degradation

Aflibercept (AFL) is an Fc fusion protein used in the treatment of colorectal cancers and different ophthalmological diseases. There are two medicines in which AFL is the active substance: Zaltrap and Eylea, referred as ziv-AFL and AFL respectively. No proper accelerated degradation studies were published on either AFL or ziv-AFL. These studies are essential during research, development and manufacturing stages. Here, we characterized ziv-AFL and submitted it to different stress conditions: light, 60 °C, freeze-thaw cycles, changes in pH, high hypertonic solution and strong denaturing conditions. We used an array of techniques to detect aggregation (SE-HPLC/DAD and DLS), changes in secondary structure (Far-UV circular dichroism), changes in conformation or tertiary structure (Intrinsic tryptophan fluorescence) and alterations in functionality (ELISA). Results indicate that aggregation is common degradation pathway. Two different types of aggregates were detected: dimers and high molecular weight aggregates attributed to β-amyloid-like structures. Secondary structure was maintained in most of the stress tests, while conformation was altered by almost all the tests except for the freeze-thaw cycles. Functionality, evaluated by its immunochemical reaction with VEGF, was found to be stable but with decrease when exposed to light and with likely partial inactivation of the drug when pH was altered.

Off-label use of bevacizumab for wet age-related macular degeneration in Europe

PURPOSE

To analyse current off-label use of bevacizumab for wet age-related macular degeneration (AMD) in Europe.

METHODS

The study was conducted as a combined survey and literature review. It included the 22 most populous countries in Europe. In each country, ophthalmologists with particular knowledge about off-label treatment responded to a questionnaire.

RESULTS

Answers were obtained from twenty European countries. The off-label use of bevacizumab for wet AMD greatly differed between nations; the bevacizumab proportion varied from non-existent (0%) to very high (97%). There were also large disparities within single countries (e.g. 0-80%), which were attributable to differences in regional decision-making. Both governmental institutions and national ophthalmological societies expressed highly diverging opinions on the use of off-label treatment. Intravitreal administration of bevacizumab had been a matter of legal dispute in several countries. The question about responsibility for off-label therapy mainly remained unanswered.

CONCLUSIONS

There was a highly varying utilization of bevacizumab between European countries. Despite an intention of a consistent approach to medical regulations, Europe has not yet reached a professional or political consensus on the ophthalmic off-label use of bevacizumab.

A new method for pharmaceutical compounding and storage of anti-VEGF biologics for intravitreal use in silicone oil-free prefilled plastic syringes

Intravitreal injections of antibody-based biologics targeting vascular endothelial growth factor (VEGF) are highly effective and have markedly decreased the risk of visual impairment associated with prevalent retinal diseases, such as neovascular age-related macular degeneration and diabetes macular oedema. The diseases are chronic in their nature, and most patients need long-term therapy to suppress disease activity. We previously reported a compounding method for repackaging and storage of aflibercept (Eylea), a commonly used anti-VEGF biologic, in silicone oil-coated plastic syringes without compromising drug stability or activity. In addition to improving safety and time spent per patient, compounding of anti-VEGF biologics enables single-dose vials to be split into multiple syringes, thereby considerably reducing waste and drug expenses. However, symptomatic silicone oil droplets may deposit in the eye’s vitreous body after repetitive injections. To fully avoid this complication, we here report on a novel pharmaceutical compounding method using silicone oil-free syringes and a 33 G × 9 mm Low Dead Space Needle hub injection needle. We evaluate the method for three anti-VEGF biologics commonly used in ophthalmology: aflibercept, ranibizumab (Lucentis) and bevacizumab (Avastin). Our results show that compounding and storage for one week does not compromise the functional activity of the biologics and allows for safe and cost-effective compounding of anti-VEGF biologics for intravitreal injections in prefilled silicone oil-free syringes.

Endophthalmitis in Oslo, Norway

PURPOSE

To study the incidence, aetiology, pathogenic causes, treatment and visual outcomes of endophthalmitis (EO) at the Department of Ophthalmology, Oslo University Hospital (OUS), Norway.

METHODS

Retrospective registry study. Medical records of all EO patients treated at OUS over a 2-year period were reviewed.

RESULTS

The study identified 46 EO eyes of 44 patients; 19 eyes had postcataract surgery EO (PCE), and 6 eyes had postinjection EO (PIE). Of 4778 primary cataract surgeries performed at OUS, there was one PCE (incidence 0.21 per 1000; 95% CI 0.04-1.19 per 1000). Of 38 134 intravitreal injections performed at OUS, there were 3 PIE (incidence 0.08 per 1000; 95% CI 0.03-0.23 per 1000). Among 15 751 cataract surgeries performed at other ophthalmic centres in Oslo and Akershus County (OOC), there were 15 PCE (incidence 0.95 per 1000; 95% CI 0.58-1.57 per 1000). Of 3000 intravitreal injections performed at OOC, there was one PIE (incidence 0.33 per 1000; 95% CI 0.059-1.89 per 1000). For neither PCE nor PIE, there were significant differences in odds ratios between OUS and OOC. The odds ratio for PCE versus PIE was, however, 8.0 (95% CI 2.7-24.0; p < 0.001). Cultures were positive in 35 of 46 eyes (76%). The most common pathogen was Staphylococcus epidermidis. Twenty-two eyes (48%) achieved a clinically significant improvement in visual function (≥0.3 logMAR) following treatment.

CONCLUSION

The overall risk of PCE and PIE was low. It was, however, higher for PCE than PIE, probably reflecting the relative difference in invasiveness between the procedures.

Short-term effect on the ocular circulation induced by unilateral intravitreal injection of aflibercept in age-related maculopathy

Purpose

Intravitreal injection of anti‐vascular endothelial growth factor (anti‐VEGF) is the standard treatment for neovascular age‐related macular degeneration (AMD). As VEGF is a physiological key player for regulating retinal vascular tone, questions have been raised whether the application of anti‐VEGF could induce alterations in ocular perfusion.

Methods

The study included 20 eyes from 20 Caucasian patients with unilateral neovascular AMD and 20 fellow eyes. All eyes were treated with standard intravitreal injection of aflibercept (IVA). Measurements of blood flow at the optic nerve head (ONH) and the choroid were performed with laser speckle flowgraphy (LSFG). The intraocular pressure (IOP), systolic and diastolic blood pressure, heart rate, mean arterial pressure (MAP) and ocular perfusion pressure (OPP) were analysed. Measurements were performed at baseline and repeated immediately after the injection and 30 and 45 min later.

Results

Mean time between injection of aflibercept and first follow‐up was 8:56 ± 4:25 min. The injection led to significant rise in IOP. In the injected eyes, mean blur rate (MBR, i.e. a relative measure of perfusion and the main outcome parameter of LSFG) within the major vessels of the ONH as well as at the entire ONH region decreased significantly (p < 0.001). No change in MBR was observed in the fellow eye. Choroidal blood flow was maintained stable in both eyes.

Conclusion

Intravitreal injection of aflibercept (IVA) led to a short‐term reduction in perfusion only in the treated eye. This was independent from IOP, indicating a direct pharmacological effect. No changes in choroidal perfusion were observed during the first 45 min after the injection.

TRIM21-From Intracellular Immunity to Therapy

Tripartite motif containing-21 (TRIM21) is a cytosolic ubiquitin ligase and antibody receptor that provides a last line of defense against invading viruses. It does so by acting as a sensor that intercepts antibody-coated viruses that have evaded extracellular neutralization and breached the cell membrane. Upon engagement of the Fc of antibodies bound to viruses, TRIM21 triggers a coordinated effector and signaling response that prevents viral replication while at the same time inducing an anti-viral cellular state. This dual effector function is tightly regulated by auto-ubiquitination and phosphorylation. Therapeutically, TRIM21 has been shown to be detrimental in adenovirus based gene therapy, while it may be favorably utilized to prevent tau aggregation in neurodegenerative disorders. In addition, TRIM21 may synergize with the complement system to block viral replication as well as transgene expression. TRIM21 can also be utilized as a research tool to deplete specific proteins in cells and zebrafish embryos. Here, we review our current biological understanding of TRIM21 in light of its versatile functions.

Sustained Anti-Vascular Endothelial Growth Factor Activity of Aflibercept (Eylea) After Storage in Polycarbonate Syringes Used for Intravitreal Injection: A Pathway to Safety and Efficiency

Purpose: Aflibercept (Eylea™, Regeneron) is supplied in single-use glass vials along with 1 cc polycarbonate syringes. We sought to determine if storage of aflibercept for sustained periods within these syringes would result in loss of antivascular endothelial growth factor (anti-VEGF) activity. Methods: Aflibercept samples were drawn from commercially available glass vials into manufacturer-supplied 1-mL syringes and stored at 4°C. Anti-VEGF activity was assessed using enzyme-linked immunosorbent assays at the following storage durations: 0, 4, 9, 14, and 28 days. Frozen samples stored at -20°C for 28 and 56 days were also assayed. Also, a subset of aflibercept samples was stored and then diluted to 1:10 and progressively smaller concentrations and the assays repeated. Aggregation of aflibercept was tested using a dynamic light scattering assay. Results: There were no statistical differences in anti-VEGF activity among aflibercept samples of 1:1 or 1:10 dilution stored at either 4°C or -20°C at any of the storage intervals (P > 0.05). We also observed persistence of robust anti-VEGF activity for up to 14 days when diluted poststorage to 1:16,000, a concentration that would be expected after >7 vitreous half-lives within the eye (estimated at >50 days). No evidence of drug aggregation in specimens stored for 14 days was observed. Conclusions: Our findings support feasibility of prefilling and storage of aflibercept within manufacturer-supplied polycarbonate syringes for as long as 14 days before use under pharmacy-based sterile conditions, facilitating greater safety and efficiency in many clinics delivering anti-VEGF therapy.