Silicone oil microdroplets and protein aggregates in repackaged bevacizumab and ranibizumab: effects of long-term storage and product mishandling

Clinical features, management and outcomes of patients with sterile endophthalmitis associated with intravitreal injection of antivascular endothelial growth factor

PURPOSE

Analyze clinical features, management and outcomes of patients with sterile endophthalmitis associated with intravitreal antivascular endothelial growth factor.

METHODS

Observational retrospective case series of patients with sterile endophthalmitis following anti-VEGF intravitreal injections. Clinical data of patients treated with intravitreal anti-VEGFs during one year have been revised. Those who have presented an episode of sterile endophthalmitis are analyzed and their causality and management are studied.

RESULTS

Seven patients have had a sterile endophthalmitis onset within 4days after intravitreal injection (aflibercept n=5 and ranibizumab n=2). These patients have some active neovascular condition: age related macular degeneration (n=4), myopic choroidal neovascularization (n=1) or macular edema: diabetic macular edema (n=1), branch retinal vein occlusion (n=1). Shared signs and symptoms included painless vision loss, anterior chamber and vitreous cell and lack of hypopyon. In all patients, visual acuity returned to within one line of baseline acuity.

CONCLUSION

Differentiating cases of sterile from infectious endophthalmitis may be challenging. It is crucial to differentiate both entities as a good diagnosis determines the visual prognosis. We should be aware of minimal inflammation after repeated intravitreal injections in order to establish the adequate treatment.

Critical analysis of techniques and materials used in devices, syringes, and needles used for intravitreal injections

Intravitreal injections have become the most commonly performed intraocular treatments worldwide. Because intravitreal injections may induce severe adverse events, such as infectious and noninfectious endophthalmitis, cataract, ocular hypertension, vitreous hemorrhage, or retinal detachment, appropriate awareness of the materials and techniques used are essential to reduce these sight-threatening complications. This review provides insights into the needles, syringes, silicone oil coating, sterilization methods, devices to assist intravitreal injections, scleral piercing techniques using needles, syringe handling, anesthesia, and safety issues related to materials and techniques. It is paramount that physicians be aware of every step involved in intravitreal injections and consider the roles and implications of all materials and techniques used. The ability to understand the theoretical and practical circumstances may definitely lead to state-of-the-art treatments delivered to patients. The most important practical recommendations are: choosing syringes with as little silicone oil as possible, or, preferably, none; avoiding agitation of syringes; awareness that most biologics (e.g., antiangiogenic proteins) are susceptible to changes in molecular properties under some conditions, such as agitation and temperature variation; understanding that improper materials and techniques may lead to complications after intravitreal injections, e.g., inflammation; and recognizing that some devices may contribute to an enhanced, safer, and faster intravitreal injection technique.

Issues with Intravitreal Administration of Anti-VEGF Drugs

Purpose

To provide an update of summary of risk factors and side effects of long-term use and contamination of intravitreal anti-VEGF injections.

Methods

We reviewed relevant publications of the topic of contamination of anti-VEGF injections and long-term side effects due to this reason.

Results

Due to the long-term use of anti-VEGF drugs and the higher number of injections worldwide, various studies have shown side effects in recent years, ranging from increased intraocular pressure to visual disturbing silicone oil vesicles in the vitreous cavity. Several studies have demonstrated that both the drug and the processing, storage, environmental factors and the material and design of the syringes have a decisive influence on these side effects.

Conclusion

The risks of deposits from syringes in the eye can be significantly reduced by various optimizations in transport, storage and syringe and cannula selection.

Probing the Interfacial Interactions of Monoclonal and Bispecific Antibodies at the Silicone Oil-Aqueous Solution Interface by Using Sum Frequency Generation Vibrational Spectroscopy

Silicone oil has been widely utilized in the pharmaceutical industry especially as a lubricant coating commonly used in syringes for the smooth delivery of drugs. Protein structure perturbation and aggregation have been reported upon protein contacting silicone oil by using indirect methods and ex-situ techniques. The conclusions derived from such indirect and ex-situ methods may not truly reflect the exact nature of the protein-silicone oil interfacial interactions. Recently, we have successfully demonstrated that sum frequency generation (SFG) vibrational spectroscopy can be used as a powerful and direct method of studying the fusion protein-silicone oil interfacial interactions in situ and in real time. In this article, we studied monoclonal and bispecific antibody interactions with the silicone oil surface by using SFG spectroscopy. Being structurally and functionally different in the nature of fusion proteins and antibodies, this study is important in enhancing our current understanding of protein-silicone oil interfacial interactions. Both types of antibodies investigated here readily and strongly adsorb onto the silicone oil surface and remain stable at least for 10 h. SFG spectra in the amide I region for monoclonal and bispecific antibodies centered at 1660 and 1665 cm^-1, respectively, suggest the difference in their molecular structures. The absence of the antibody signals in the amide I region of time-dependent and static SFG spectra obtained for preadsorbed antibodies onto silicone oil after contacting polysorbate 80 (PS-80) surfactant suggests that PS-80 can effectively remove both types of antibodies from the silicone oil surface. This study demonstrated the feasibility of using SFG spectroscopy as a powerful tool for probing the antibody-interfacial interactions in situ and in real time.

Subvisible Particles in IVIg Formulations Activate Complement in Human Serum

When administered intravenously, various particles and nanomedicines activate complement, potentially leading to infusion reactions and other adverse drug reactions. Particles form within formulations of therapeutic proteins due to stresses incurred during shipping, handling, and administration to patients. In this study, IVIg solutions were stored in multiple types of vials and prefilled syringes and exposed to agitation and freeze-thaw stresses to generate particles. The stressed samples were added to human serum to determine whether these particles activated complement. Subvisible IVIg particles ranging in size between 2 and 10 microns activated complement in a fashion that was linearly dependent on the number of particles dosed, whereas little correlation was found between doses of larger particles (>10 microns) and complement activation. Activation of complement by subvisible particles of IVIg followed the alternative pathway, as shown by the release of complement cascade factor Bb and the production of the anaphylatoxins C3a and C5a without generation of C4a. The number and the morphology of subvisible particles formed depended on the applied stress, formulation, and on the container material. But the capacity of the 2- to 10-micron-sized particles to activate complement in human serum appeared to depend only on particle concentration.

LONG-TERM PHYSICAL STABILITY, STERILITY, AND ANTI-VEGF BIOACTIVITY OF REPACKAGED BEVACIZUMAB IN 2-ML GLASS VIALS

PURPOSE

Repackaged bevacizumab in single-dose, prefilled syringes for intravitreal injection is available, but with shelf life limited from 60 days to 90 days. For the Study of COmparative Treatments for REtinal Vein Occlusion 2 (SCORE2), 2-mL sterile glass vials were used rather than prefilled syringes to provide a longer shelf life for study supplies.

METHODS

Repackaged bevacizumab in glass vials was tested at release and, for 1 lot, after 1, 3, 6, and 12 months for physical stability, including concentration, purity and appearance, and for sterility and endotoxins. Vials from 2 lots were tested at release and after 20 months and 21 months, respectively. One lot was tested at 21 months for anti-VEGF bioactivity compared with a fresh supply of commercial bevacizumab.

RESULTS

Repackaged bevacizumab in 2-mL glass vials continued to meet all quality release specifications and remain sterile for up to 21 months. In addition, no degradation in anti-VEGF bioactivity was observed at 21 months compared with a fresh bevacizumab control.

CONCLUSION

Bevacizumab can be repackaged into small, single-dose glass vials for intravitreal injection and the qualities of the commercial product maintained, including anti-VEGF bioactivity, for up to 21 months in refrigerated storage. Consideration should be given to repackaging bevacizumab for ophthalmic use in small glass vials as opposed to plastic syringes.

LARGE SILICONE DROPLETS AFTER INTRAVITREAL BEVACIZUMAB (AVASTIN)

PURPOSE

Despite its off-label status, intravitreal bevacizumab is the most commonly used intraocular anti-vascular endothelial growth factor agent. Regulation of compounding pharmacies has recently increased to make compounded pharmaceuticals safer. Despite these changes, a marked increase in symptomatic, large silicone oil droplets following intravitreal bevacizumab injections was noticed.

METHODS

Retrospective chart review was performed. Within a single private practice, patients who were noted to have large or symptomatic silicone oil bubbles after an intravitreal injection were reviewed.

RESULTS

A recent, dramatic increase in the incidence of large or symptomatic silicone oil droplets was noted, with 23 cases noted in the past 5 months, compared with 1 in the previous decade. Patients frequently noted a circular floater consisting of a dark ring surrounding a bright central area immediately following an injection of intravitreal bevacizumab. All bevacizumab injections were from single-piece insulin syringes. B-scan ultrasonography produced a very characteristic reverberation pattern. No inflammation or visual acuity loss was noted because of the droplets; however, some patients were annoyed enough to consider vitrectomy.

CONCLUSION

Patients should be carefully evaluated for this possibility, and the characteristic symptom of a round floater consisting of a dark ring surrounding a bright center, and the prominent reverberation pattern on B-scan ultrasonography may help increase detection. Changes in consent forms and discussion of this possibility are indicated while investigation into the cause of this increased incidence continues, especially if one is administering bevacizumab via the one-piece insulin syringes commonly used by compound pharmacies.

Selective separation method of aggregates from IgG solution by aqueous two-phase system

Aggregation of immunoglobulin G (IgG) is a serious concern that results in immunogenicity in pharmaceutical applications. Removal of the small and soluble aggregates in protein solutions through a simple method remains challenging. Here we show that an aqueous two-phase system (ATPS) can be used for the elimination of soluble aggregates from IgG solution. Polyethylene glycol (PEG) and dextran (DEX) were selected as components of the ATPS. As expected, IgG monomers were partitioned into the top or bottom phases of ATPS. Interestingly, almost all the small and soluble aggregates of IgG were extracted to the interface between top and bottom phases, rather than in the liquid phases. The partitioning of monomers and aggregates of IgG can be attributed to the solubility of these protein states in PEG and DEX. Thus, ATPS using PEG and DEX can be employed for the simple removal method of soluble aggregates from IgG solution.

Silicone oil droplets in repackaged anti–vascular endothelial growth factors for intravitreal injections: In search of the main source of contamination

Introduction:

Repackaging of anti–vascular endothelial growth factors in polypropylene syringes lubricated with silicone oil for intravitreal use is associated with the presence of intravitreal silicone oil droplets. The objective of this study is to assess how the use of silicone-free syringes (for storage and/or administration) would reduce the amount of silicone oil droplets in the product to be administered.

Methods:

Two 16 mL vials of bevacizumab were repackaged at the compounding pharmacy to obtain four sets of product, each consisting of three 1.2 mL tubes of the drug repackaged in different ways. Set A was repackaged according to routine practice, that is, the drug was placed into 1 mL siliconized syringes and 60 µL aliquots were extracted with 0.5 mL insulin siliconized syringes until reaching 1.2 mL. In set B, a 1-mL silicone-free syringe was used, followed by a 0.5 mL siliconized syringe. In set C, only 0.5 mL siliconized syringes were used. In set D, only the 1-mL silicone-free syringe was used. Micro-Flow Imaging technology was used for quantifying silicone oil droplet–like particles below 25 µm.

Results:

Silicone oil droplet–like particles were absent in set D. Set C had the highest average frequency of these particles, which was much lower in sets A and B. Set B had the lowest frequency.

Conclusion:

0.5 mL insulin syringes with staked-in needles used for supplying the product seem to be the main source of silicone oil contamination in repackaged anti–vascular endothelial growth factors. Silicone-free insulin syringes with staked-in needles would be strongly recommended for supplying anti–vascular endothelial growth factor intravitreal injections from compounding pharmacies.

The Effect of Anti-Vascular Endothelial Growth Factor Agents on Intraocular Pressure and Glaucoma: A Report by the American Academy of Ophthalmology

PURPOSE

To assess the effect of intravitreal injections of anti-vascular endothelial growth factor (VEGF) agents on immediate and long-term intraocular pressure (IOP) elevation and glaucoma.

METHODS

Literature searches of the PubMed and Cochrane databases, last conducted in April 2018, yielded 253 unique citations. Of these, 41 met the inclusion criteria and were rated according to the strength of evidence. Two articles were rated level I, 17 were rated level II, and 15 were rated level III; an additional 7 were excluded because of poor study design and lack of relevance to the topic under evaluation.

RESULTS

The studies that reported on short-term IOP elevation (i.e., between 0 and 60 minutes) showed that an immediate increase in IOP is seen in all patients when measured between 0 and 30 minutes of intravitreal injection and that the IOP elevation decreases over time. The data on long-term IOP elevation were mixed; 7 studies reported that between 4% and 15% of patients developed sustained elevation of IOP at 9 to 24 months after injection, whereas 6 studies found no long-term change in IOP from 1 to 36 months after injection. Pretreatment with glaucoma medications, anterior chamber tap, vitreous reflux, longer intervals between injections, and longer axial lengths were associated with lower IOP elevations after injection. Data were mixed on the relationship between IOP increase and the type of intravitreal injection, number of intravitreal injections, preexisting glaucoma, and globe decompression before injection. There were no data on the onset or progression of glaucoma in the studies reviewed in this assessment.

CONCLUSIONS

Intravitreal injection of anti-VEGF agents results in an immediate and transient increase in IOP. A long-term increase in IOP also may be seen, and further studies are needed to determine at-risk populations. Although there is some suggestion in the literature, there is currently insufficient data to determine the impact of intravitreal anti-VEGF injections on glaucoma progression. Although pretreatment with glaucoma medications, performing anterior chamber paracentesis, or increasing the interval between injections may reduce the impact of transient IOP elevation, the clinical significance and associated risks of these interventions are unknown.

Interactions Between Biological Products and Product Packaging and Potential Approaches to Overcome Them

Biological products such as protein-based biopharmaceuticals are playing an important role in the healthcare and pharmaceutical industry. The interaction between biological products and packaging materials has become the focus of many studies since it can reduce the effectiveness of biological products. These interactions are heavily influenced by the surface properties and physicochemical nature of the therapeutic agents and the packaging materials. Therefore, it is critical to understand the interactions between packaging materials and biological products in order to design biocompatible packaging materials and develop approaches to minimize adverse interactions. We describe the interactions that occur when using several common packaging materials, including glass and polymer. We discuss the interaction between these materials and biological products such as blood, blood derivatives, recombinant proteins, monoclonal antibodies, and gene therapeutics. We also summarize approaches for overcoming these interactions. Understanding the interactions between biological materials and packaging materials is critical for the development of novel packaging materials that improve the safety of pharmaceutical products.

EFFECT OF SERIAL ANTERIOR CHAMBER PARACENTESIS ON SUSTAINED INTRAOCULAR PRESSURE ELEVATION IN PATIENTS RECEIVING INTRAVITREAL ANTI-VASCULAR ENDOTHELIAL GROWTH FACTOR THERAPY

PURPOSE

To investigate the effect of serial anterior chamber (AC) paracenteses in eyes with sustained elevations of intraocular pressure (IOP) in the setting of repeated intravitreal injections (IVI) of anti-vascular endothelial growth factor medications.

METHODS

This is a retrospective records review of patients undergoing IVI of anti-vascular endothelial growth factor medication (bevacizumab, ranubizumab, or aflibercept), who demonstrated a sustained elevation of preinjection IOP and also received AC paracentesis immediately after IVI on at least three consecutive visits. Changes in preinjection IOP and cup-to-disk (C:D) ratio were compared before and after the initiation of IVI and before and after the introduction of AC paracenteses with each subsequent IVI.

RESULTS

Twenty-three eyes of 17 patients receiving a median of 26 IVI experienced a rise in preinjection IOP from 16.3 mmHg to 21.1 mmHg (P = 0.004) and an increase in mean C:D ratio from 0.37 to 0.47 (P = 0.0002). After introduction of AC paracenteses (median of 12), mean IOP was returned to baseline 16.00 mmHg (P = 0.002), mean C:D ratio stabilized (0.50, P = 0.197), and maximum IOP decreased from 26.8 mmHg to 23.0 mmHg (P = 0.05). Nineteen (82.6%) eyes required an increase in topical glaucoma medications during the study period, and 13 (56.5%) still required additional therapies after initiation of AC paracenteses. Five eyes (38.5%) required laser or glaucoma drainage device procedures.

CONCLUSION

Serial AC paracenteses reduced immediate postinjection IOP, and along with standard glaucoma care in most patients, reversed preinjection IOP elevation, and stabilized optic nerve changes associated with repeated intravitreal anti-vascular endothelial growth factor injections in a subset of patients with sustained elevation of preinjection IOP.

Drug-induced Glomerulonephritis: The Spectre of Biotherapeutic and Antisense Oligonucleotide Immune Activation in the Kidney

Prevalence of immune-mediated glomerulonephritis has increased in preclinical toxicity studies, with more frequent use of biotherapeutic agents (especially antigenic humanized molecules) and antisense oligonucleotide (ASO) therapies. Immune complex disease affects a small number of study monkeys, often correlates with antidrug antibody (ADA) titers, and occurs at a dose that favors immune complex formation or impedes clearance. While preclinical glomerulonephritis often fails to correlate with evidence of glomerular or vascular injury in human clinical trials and is not considered predictive, additional animal investigative immunohistochemical work may be performed to substantiate evidence for immune complex pathogenesis. While ADA is most commonly encountered as a predisposing factor with biotherapeutic agents, complement activation may occur without circulating complexes, and other mechanisms of non-ADA immune-mediated glomerulonephritis have been observed including nonendogenous immune aggregates and immunoregulatory pharmacology. Although glomerulonephritis associated with oligonucleotide therapies has been noted occasionally in preclinical studies and more rarely with human patients, pathophysiologic mechanisms involved appear to be different between species and preclinical cases are not considered predictive for humans. ADA is not involved in oligonucleotide-associated cases, and complement fixation plays a more important role in monkeys. Recent screening of ASOs for proinflammatory activity appears to have decreased glomerulonephritis incidence preclinically.

Principles of pharmacology in the eye

The eye is a highly specialized organ that is subject to a huge range of pathology. Both local and systemic disease may affect different anatomical regions of the eye. The least invasive routes for ocular drug administration are topical (e.g. eye drops) and systemic (e.g. tablets) formulations. Barriers that subserve as protection against pathogen entry also restrict drug permeation. Topically administered drugs often display limited bioavailability due to many physical and biochemical barriers including the pre-corneal tear film, the structure and biophysiological properties of the cornea, the limited volume that can be accommodated by the cul-de-sac, the lacrimal drainage system and reflex tearing. The tissue layers of the cornea and conjunctiva are further key factors that act to restrict drug delivery. Using carriers that enhance viscosity or bind to the ocular surface increases bioavailability. Matching the pH and polarity of drug molecules to the tissue layers allows greater penetration. Drug delivery to the posterior segment is a greater challenge and, currently, the standard route is via intravitreal injection, notwithstanding the risks of endophthalmitis and retinal detachment with frequent injections. Intraocular implants that allow sustained drug release are at different stages of development. Novel exciting therapeutic approaches include methods for promoting transscleral delivery, sustained release devices, nanotechnology and gene therapy.

Silicone Oil Droplets are More Common in Fluid From BD Insulin Syringes as Compared to Other Syringes

Purpose:

During 2016 and 2017, numerous retina specialists reported silicone oil droplets after intravitreal injection, primarily associated with insulin syringes with a fixed needle. By contrast, adverse events were relatively rare for tuberculin syringes. We hypothesized that fixed-needle syringe injections have more silicone droplets due to the lack of dead space at the syringe–needle junction.

Methods:

Fluid from Becton Dickenson (BD) insulin syringes, BD tuberculin syringes, Henke Sass Wolf (HSW) insulin syringes, and HSW silicone-free syringes was examined microscopically for silicone oil droplets. Fluid was sampled at the beginning, middle, and end of injection; and droplets were photographed and quantified.

Results:

Silicone oil droplets were identified in 30% of the BD insulin syringes, measuring 0.9 ± 0.2 mm3; no oil droplets were found in BD tuberculin syringes or HSW silicone-free syringes (analysis of variance, P < .05). All 6 samples with silicone oil droplets were from the end of injection (full depression of the plunger), while samples from the beginning and middle of injections did not have droplets. Challenging syringes with extra silicone oil resulted in increased droplets for fixed-needle syringes (but not for syringes with detachable needles).

Conclusion:

Significant silicone oil droplets were present in BD insulin syringes and were expressed at the end of injection (with plunger depressed maximally), supporting the hypothesis that insulin syringe injections have more droplets due to the lack of dead space where the plunger meets the hub of the needle. However, there are additional factors such as the amount or type of silicone lubricant in a syringe.

The acute and chronic effects of intravitreal anti-vascular endothelial growth factor injections on intraocular pressure: A review

The acute and chronic effects of repeated intravitreal antivascular endothelial growth factor (VEGF) injections on intraocular pressure have not been fully characterized, and the development of sustained ocular hypertension could adversely affect patients who are at risk of glaucomatous optic neuropathy. As expected, volume-driven, acute ocular hypertension immediately follows intravitreal injection, but this pressure elevation is generally transient and well tolerated. Several medications have been investigated to limit acute ocular hypertension following anti-VEGF therapy, but the benefits of pretreatment are not conclusive. Chronic, sustained ocular hypertension, distinct from the short-term acute ocular hypertension after each injection, has also been associated with repeated intravitreal anti-VEGF injections. Risk factors for chronic ocular hypertension include the total number of injections, a greater frequency of injection, and preexisting glaucoma. Proposed mechanisms for chronic ocular hypertension include microparticle obstruction, toxic or inflammatory effects on trabecular meshwork, as well as alterations in outflow facility by anti-VEGF agents. Although limiting anti-VEGF therapy could minimize the risk of both acute and chronic ocular hypertension, foregoing anti-VEGF therapy risks progression of various macular diseases with resulting permanent central vision loss. While definitive evidence of damage to the retinal nerve fiber layer is lacking, patients receiving repeated injections should be monitored for ocular hypertension and patients in whom sustained ocular hypertension subsequently developed should be periodically monitored for glaucomatous changes with optic nerve optical coherence tomography and static visual fields.

Sustained intraocular pressure elevation in eyes treated with intravitreal injections of anti-vascular endothelial growth factor for diabetic macular edema in a real-life setting

PURPOSE

The aim of this study was to investigate the sustained intraocular pressure (IOP) elevation after repeated anti-VEGF intravitreal injections (IVI) in patients with diabetic macular edema (DME).

METHODS

A retrospective study included 140 eyes without prior glaucoma, treated with at least three anti-VEGF injections for DME between 2012 and 2016. IOP elevation was defined by an increase above baseline IOP by ≥6 mmHg. Baseline IOP was defined as the mean of IOP values before treatment initiation. Three groups were differentiated: group 1 without IOP elevation, groups 2 and 3 with IOP elevation and IOP <21 mmHg (group 2) and ≥21 mmHg (group 3). Rate and several risk factors of IOP elevation were assessed and compared between the three groups.

RESULTS

IOP elevation occurred in ten eyes (7.1%). IOP was <21 mmHg in six eyes and ≥21 mmHg in four eyes. Statistically significant associations were found between IOP elevation and the number of injections, and HbA1c level. Two patients required local hypotonic treatment.

CONCLUSIONS

In a real-life setting, we confirmed in eyes with center-involved DME without prior glaucoma or IOP elevation that repeated anti-VEGF IVI may increase the risk of sustained IOP elevation in about 7% of eyes.

Incidence of Presumed Silicone Oil Droplets in the Vitreous Cavity After Intravitreal Bevacizumab Injection With Insulin Syringes

Importance

Intravitreal bevacizumab is a frequently used antivascular endothelial growth factor medication in the United States, but its off-label use is associated with risks associated with the compounding preparation.

Objective

To determine the incidence of presumed silicone oil droplets after intravitreal bevacizumab was prepared in insulin syringes by a compounding pharmacy.

Design, Setting, and Participants

A retrospective review was conducted of 60 patients who experienced intravitreal silicone oil droplets in the eye after intravitreal bevacizumab injections from a single specialist practice from October 1, 2015, to November 30, 2016. Bevacizumab, 1.25 mg/0.05 mL, was delivered in insulin syringes with a 31-gauge needle.

Main Outcomes and Measures

Small, round clear spheres in vitreous on dilated biomicroscopic retinal examination.

Results

Over a 14-month period involving 6632 intravitreal bevacizumab injections, 60 cases (35 [58%] women) of intravitreal silicone droplets were identified. Mean [SD] age of the patients was 80 [12] years; the population comprised 48 white, 9 Asian, and 3 Hispanic patients. The incidence of silicone oil droplet injections was 0.03% (1 of 3230) from October 2015 to April 2016 and 1.7% (59 of 3402) from May to November 2016 (Fisher exact test, P < .001; odds ratio [OR], 57; 95% CI, 9.8-2260). From May to November 2016, nonpriming the syringe before the intravitreal injection had a higher risk of intravitreal silicone oil droplets compared with priming the syringe (6.4% [47 of 739] vs 0.5% [12 of 2627]; Fisher exact test, P < .001; OR, 15.1; 95% CI, 7.9-33.4). Among the 60 cases, 41 patients (68%) were symptomatic, and the main symptom was floaters with spots of light. Among the patients with floaters, 36 (88%) improved over time (range, 2-8 months) despite the silicone droplets still being present on ophthalmoscopic examination.

Conclusions and Relevance

An increase in intravitreal silicone oil associated with bevacizumab prepared with insulin syringes was documented. Priming the syringe before injection was associated with a lower frequency of this complication. These findings suggest that physicians should counsel their patients on the risk of floaters with intravitreal bevacizumab preloaded in insulin syringes.

VEGF as a Paracrine Regulator of Conventional Outflow Facility

Purpose

Vascular endothelial growth factor (VEGF) regulates microvascular endothelial permeability, and the permeability of Schlemm's canal (SC) endothelium influences conventional aqueous humor outflow. We hypothesize that VEGF signaling regulates outflow facility.

Methods

We measured outflow facility (C) in enucleated mouse eyes perfused with VEGF-A₁₆₄a, VEGF-A₁₆₅b, VEGF-D, or inhibitors to VEGF receptor 2 (VEGFR-2). We monitored VEGF-A secretion from human trabecular meshwork (TM) cells by ELISA after 24 hours of static culture or cyclic stretch. We used immunofluorescence microscopy to localize VEGF-A protein within the TM of mice.

Results

VEGF-A₁₆₄a increased C in enucleated mouse eyes. Cyclic stretch increased VEGF-A secretion by human TM cells, which corresponded to VEGF-A localization in the TM of mice. Blockade of VEGFR-2 decreased C, using either of the inhibitors SU5416 or Ki8751 or the inactive splice variant VEGF-A₁₆₅b. VEGF-D increased C, which could be blocked by Ki8751.

Conclusions

VEGF is a paracrine regulator of conventional outflow facility that is secreted by TM cells in response to mechanical stress. VEGF affects facility via VEGFR-2 likely at the level of SC endothelium. Disruption of VEGF signaling in the TM may explain why anti-VEGF therapy is associated with decreased outflow facility and sustained ocular hypertension.

Intravitreal Anti-VEGF Injections Reduce Aqueous Outflow Facility in Patients With Neovascular Age-Related Macular Degeneration

Purpose

We assess the effect of intravitreal anti-VEGF injections on tonographic outflow facility.

Methods

Patients with age-related macular degeneration who had received unilateral intravitreal anti-VEGF injections were recruited into two groups, those with ≤10 and those with ≥20 total anti-VEGF injections. Intraocular pressure and tonographic outflow facility of injected and uninjected fellow eyes were measured and compared between groups. Risk factors for development of reduced outflow facility also were assessed.

Results

Outflow facility was 12% lower in the injected eyes of patients who received ≥20 anti-VEGF injections, compared to contralateral uninjected eyes (P = 0.02). In contrast, there was no facility reduction for patients with ≤10 anti-VEGF injections (P = 0.4). In patients with ocular hypertension in the uninjected eye (IOP > 21 mm Hg, n = 5), the outflow facility of injected eyes was on average 46% lower (P = 0.01) than in the uninjected fellow eyes. This was significantly greater than the difference observed in patients with IOP ≤ 21 mm Hg in the uninjected eye (P = 2 × 10⁻⁴). In patients with ocular hypertension in the injected eye (n = 6) the differences in facility and IOP between contralateral eyes were significantly greater than in patients with IOP ≤ 21 mm Hg in the injected eye (P = 2 × 10⁻⁴ and P = 7 × 10⁻⁴, respectively).

Conclusions

Chronic anti-VEGF injections significantly reduce outflow facility in patients with AMD. The greatest facility reduction is observed in patients with baseline ocular hypertension. Ophthalmologists who administer anti-VEGF injections should be aware of these findings and monitor patients closely for changes in IOP or evidence of glaucoma, especially in those with pre-existing ocular hypertension.

Immunogenicity of protein aggregates of a monoclonal antibody generated by forced shaking stress with siliconized and nonsiliconized syringes in BALB/c mice

OBJECTIVE

In this study, we aimed to investigate the immunogenicity of protein aggregates of monoclonal antibodies (mAbs), generated by forced shaking stress with siliconized and nonsiliconized syringes in a mouse model.

METHODS

Samples were filled in siliconized and nonsiliconized syringes with shaking and headspace air. Characterization studies were performed using high-performance size-exclusion chromatography, nanoparticle tracking analysis, flow cytometry, micro-flow imaging and resonant mass measurement. The samples (10 or 100 μg) were subcutaneously injected into BALB/c mice for 21 days, and the anti-drug antibody (ADA) concentrations were monitored.

KEY FINDINGS

In samples shaken with siliconized syringes [SO (+)], large amounts of submicron and subvisible protein aggregates were formed by interactions with silicone oil droplets. The characteristics of protein aggregates differed between the mAb solution and shaken samples, which strongly indicates that silicone oil accelerates protein aggregation. When administered at low doses, the ADA concentration in all samples increased with repeated injections, and SO (+) induced the highest immunogenicity. However, when administered at high doses, ADA concentration decreased following prolonged repeated administration for tolerance.

CONCLUSIONS

These results indicated that mAb protein aggregation induced immunogenicity in mice, and SO (+) induced higher immunogenicity than samples shaken with nonsiliconized syringe.

Assessment of bevacizumab quality and stability in repackaged syringes for clinical use

Objectives

Among measures taken to optimise financial resources, the off-label use of bevacizumab (Avastin) in the treatment of age-related macular degeneration (AMD) involves its repackaging from higher volume dosage forms. This use requires studies to analyse the viability of the repackaged preparations to ensure their quality, safety and efficacy. Our aim was to assess the structural stability and particle size of bevacizumab after it was repackaged from the original glass vials and stored in plastic syringes.

Methods

High performance liquid chromatography by size exclusion (HPLC-SE) was used to quantify the bevacizumab and determine its degradation products after stress stability testing, with a particle size counter employed after repackaging and subsequent storage.

Results

The syringes stored for 3 days at 4°C maintained the area of the main chromatographic peak above 100±10% of its initial value, and the observed particle size is the same as at baseline (20 nm) but with a double distribution towards larger sizes.

Conclusions

This study shows how the repackaging of Avastin in plastic syringes permits their use for 3 days if stored under normal refrigeration. In this way, hospital pharmacy services can help optimise health resources without compromising the pharmaceutical standards of the drug.

Rational design of therapeutic mAbs against aggregation through protein engineering and incorporation of glycosylation motifs applied to bevacizumab

The aggregation of biotherapeutics is a major hindrance to the development of successful drug candidates; however, the propensity to aggregate is often identified too late in the development phase to permit modification to the protein's sequence. Incorporating rational design for the stability of proteins in early discovery has numerous benefits. We engineered out aggregation-prone regions on the Fab domain of a therapeutic monoclonal antibody, bevacizumab, to rationally design a biobetter drug candidate. With the purpose of stabilizing bevacizumab with respect to aggregation, 2 strategies were undertaken: single point mutations of aggregation-prone residues and engineering a glycosylation site near aggregation-prone residues to mask these residues with a carbohydrate moiety. Both of these approaches lead to comparable decreases in aggregation, with an up to 4-fold reduction in monomer loss. These single mutations and the new glycosylation pattern of the Fab domain do not modify binding to the target. Biobetters with increased stability against aggregation can therefore be generated in a rational manner, by either removing or masking the aggregation-prone region or crowding out protein-protein interactions.

A Large Outbreak of Fulminant Bacterial Endophthalmitis after Intravitreal Injection of Counterfeit Bevacizumab

PURPOSE

This study reports the findings in a large series of patients with acute bacterial endophthalmitis after intravitreal injection of bevacizumab (IVB) in two eye hospitals.

METHODS

Medical records were reviewed for patients who presented with acute fulminant endophthalmitis in one or two eyes following intravitreal injection of bevacizumab from two separate batches in two eye hospitals.

RESULTS

Twenty-eight eyes of 21 patients presented with acute endophthalmitis 12-48 hours after IVB injection. Cultures from the eyes and the vials were positive for E. coli and Citrobacter, each in one of the hospitals. All patients were initially treated with topical, intravitreal, and systemic antibiotics. Twenty-four eyes underwent pars plana vitrectomy. Best corrected visual acuity (BCVA) was 1.27 ± 0.89 logMAR before IVB injecti,on which decreased to 2.80 ± 0.45 LogMAR after presentation of endophthalmitis and 2.12 ± 0.97 logMAR three months after IVB injection. Final visual acuity was found to be no light perception in four eyes.

CONCLUSIONS

This large outbreak of E.coli and Citrobacter endophthalmitis occurred after intravitreal injection of counterfeit bevacizumab. Visual outcomes were very poor.

A cluster of presumed, noninfectious endophthalmitis after intravitreal injection of bevacizumab: long-term follow-up

PURPOSE

To report the outcome of 5 consecutive cases of presumed, noninfectious endopththalmitis following intravitreal injection of bevacizumab (IVB).

METHODS

Ten pre-loaded syringes of bevacizumab (1.25 mg/50 µL) furnished by a compounding pharmacy were injected intravitreally. Treatments were performed in the operating room by the same surgeon on 2 consecutive days.

RESULTS

Of 10 eyes, 5 showed moderate to severe ocular inflammation within a few days of injection. All patients were treated in the same surgical session. Vitreous tap performed in the patient presenting with the most severe grade of inflammation was negative for bacteria and fungi. At the time of the vitreous biopsy, this patient was injected with vancomycin 1 mg/100 µL in the vitreous cavity. Other eyes with moderate inflammation received topical and systemic antibiotics and topical steroid treatment. Visual acuity returned to pre-endophthalmitis or better levels in all eyes within 1 month. The other 5 patients treated with IVB from the same batch in the other surgical session did not develop inflammation.

CONCLUSIONS

IVB can induce noninfectious endophthalmitis. The use of compounded syringes can explain clustering of the inflammation. We were unable to identify the reasons for the variable grade of inflammation we observed in our patients.

[Extemporaneous withdrawal with a mini-spike filter: A low infection risk technique for drawing up bevacizumab for intravitreal injection]

PURPOSE

To describe a technique for extemporaneously drawing up bevacizumab for intravitreal injection (IVT) and report the rate of post-injection endophthtalmitis.

PATIENTS AND METHODS

Retrospective monocentric analysis (January 2010-December 2014) of all IVT of bevacizumab drawn up with the following technique: in the operating room (class ISO 7) through a mini-spike with an integrated bacteria retentive air filter. The surgeon was wearing sterile gloves and a mask. The assisting nurse wore a mask. The bevacizumab vial was discarded at the end of each session.

RESULTS

Six thousand two hundred and thirty-six bevacizumab injections were performed. One case of endophthalmitis was noted (0.016%). During the same period, 4 cases of endophthalmitis were found after IVT of other drugs (4/32,992; 0.012%. P=0.8).

CONCLUSION

Intravitreal injection of bevacizumab after extemporaneous withdrawal through a mini-spike filter is a simple and safe technique. The risk of postoperative endophthalmitis is very low. This simple technique facilitates access to compounded bevacizumab.

Changes in intraocular pressure in study and fellow eyes in the IVAN trial

PURPOSE

To describe changes in intraocular pressure (IOP) in the 'alternative treatments to Inhibit VEGF in Age-related choroidal Neovascularisation (IVAN)' trial (registered as ISRCTN92166560).

DESIGN

Randomised controlled clinical trial with factorial design.

PARTICIPANTS

Patients (n=610) with treatment naïve neovascular age-related macular degeneration were enrolled and randomly assigned to receive either ranibizumab or bevacizumab and to two regimens, namely monthly (continuous) or as needed (discontinuous) treatment.

METHODS

At monthly visits, IOP was measured preinjection in both eyes, and postinjection in the study eye.

OUTCOME MEASURES

The effects of 10 prespecified covariates on preinjection IOP, change in IOP (postinjection minus preinjection) and the difference in preinjection IOP between the two eyes were examined.

RESULTS

For every month in trial, there was a statistically significant rise in both the preinjection IOP and the change in IOP postinjection during the time in the trial (estimate 0.02 mm Hg, 95% CI 0.01 to 0.03, p<0.001 and 0.03 mm Hg, 95% CI 0.01 to 0.04, p=0.002, respectively). There was also a small but significant increase during the time in trial in the difference in IOP between the two eyes (estimate 0.01 mm Hg, 95% CI 0.005 to 0.02, p<0.001). There were no differences between bevacizumab and ranibizumab for any of the three outcomes (p=0.93, p=0.22 and p=0.87, respectively).

CONCLUSIONS

Anti-vascular endothelial growth factor agents induce increases in IOP of small and uncertain clinical significance.

TRIAL REGISTRATION NUMBER

ISRCTN92166560.

Bevacizumab clearance through the iridocorneal angle following intravitreal injection in a rat model

Antivascular endothelial growth factor (Anti-VEGF) agents have been widely used for a variety of ocular disorders. The etiology of sustained ocular hypertension following intravitreal administration of anti-VEGF agents is yet to be unraveled. Our study investigates and characterizes the presence of intravitreally injected bevacizumab in the aqueous outflow channels of a rat model. Choroidal neovascularization (CNV) was induced by diode laser photocoagulation to the right eye of twelve Brown Norway rats. Bevacizumab (25 mg/ml) was injected intravitreally after 3 days. Immediately after bevacizumab injection, and 3, 6, 24 and 48 h later, animals were euthanized for immunofluorescence staining. Donkey anti-human IgG labeled with Alexa Fluor(®) 488 was used for bevacizumab immunoreactivity detection. Anti-CD31 antibody was used as a marker for Schlemm's canal endothelial cells. Untreated eyes were used as negative controls. The intensity of the immunostaining was analyzed qualitatively. Bevacizumab immunoreactivity was found in the aqueous outflow channels including the trabecular meshwork and Schlemm's canal immediately after injection, and declined incrementally within the following hours. Forty-eight hours after the injection, no bevacizumab staining was detected in the aqueous outflow channel structures. Our manuscript demonstrates the presence of bevacizumab in the trabecular meshwork and Schlemm's canal structures after intravitreal injection in a CNV induced rat model. Bevacizumab molecules passed through the aqueous outflow channels within 48 h after intravitreal bevacizumab injection.

Repeated intravitreal anti-vascular endothelial growth factor injections can induce iatrogenic ocular hypertension, especially in patients with open-angle glaucoma

OBJECTIVE

To report the rate of intraocular pressure (IOP) elevation after repeated intravitreal injections (IVIs) of anti-vascular endothelial growth factor (anti-VEGF) agents and to determine the risk factors.

METHODS

A total of 193 patients (217 eyes) undergoing ranibizumab (n = 196) or bevacizumab (n = 21) IVIs were prospectively examined. The incidence of ocular hypertension (OHT) after these injections was investigated with respect to the number of injections, pre-existing open-angle glaucoma, diabetes, YAG capsulotomy, age, and sex.

RESULTS

A total of 1461 IVIs was performed. After a mean of 6.7 ± 7.1 IVIs (range, 1-49), 4.6% (n = 10) had IOP elevation more than 25 mm Hg and required medical treatment (1.4% of them spiked above 30 mm Hg). Patients with pre-existing glaucoma experienced higher prevalence of OHT (12.9%) and greater rates than the control group (19.6 ± 5.7 mm Hg vs 16.4 ± 3.9 mm Hg, p < 0.001). No significant difference was found in the diabetes subgroup (n = 66, p = 0.62) or in the YAG capsulotomy subgroup (n = 24, p = 0.51) compared with the control group. The IOP peak was significantly correlated with the total number of IVIs (p = 0.0002, r = 0.25).

CONCLUSIONS

Serial IVIs may lead to persistent IOP elevation that requires IOP-lowering therapy. The risk is correlated with the number of injections and increases in the glaucoma population, and must be checked during follow-up.

Intraocular pressure trends after intravitreal injections of anti-vascular endothelial growth factor agents for diabetic macular edema

PURPOSE

To study intraocular pressure (IOP) trends and risk factors of IOP elevation after intravitreal anti-vascular endothelial growth factor injections in diabetic macular edema.

METHODS

A retrospective review of 760 eyes treated with intravitreal anti-vascular endothelial growth factor injections for diabetic macular edema was performed. The rate and risk factors of IOP elevation were assessed. Intraocular pressure elevation was defined as an increase above baseline IOP by ≥ 6 mmHg, increase above baseline by > 20%, or IOP elevation to > 24 mmHg on 2 or more consecutive visits after treatment. When more than one pretreatment IOP reading was available, baseline IOP was calculated as the mean of the available pretreatment IOP readings (up to a maximum of three last IOP readings). Intraocular pressure elevation was considered transient unless it was maintained throughout the follow-up or required treatment (persistent elevation).

RESULTS

Over a mean follow-up of 18 months, persistent and transient IOP elevation occurred in 44 (5.8%) and 53 (7%) eyes, respectively. The majority of eyes with persistent IOP elevation (70.4%) showed IOP elevation of > 20% from baseline. Only 13 eyes (1.71%) met the more strict criteria (> 6 mmHg from baseline or an IOP elevation > 24 mmHg). Final IOP was higher in the persistent IOP elevation group than the rest of the eyes (P < 0.001). Only the number of injections was associated with IOP elevation (P < 0.001).

CONCLUSION

Persistent IOP elevation after intravitreal anti-vascular endothelial growth factor injections for diabetic macular edema is uncommon but may be associated with a higher number of injections.

Storage stability of bevacizumab in polycarbonate and polypropylene syringes

PURPOSE

To compare and examine the storage stability of compounded bevacizumab in polycarbonate (PC) and polypropylene (PP) syringes over a 6-month period. PC syringes have been used in a recent clinical study and bevacizumab stability has not been reported for this type of syringe.

METHODS

Repackaged bevacizumab was obtained from Moorfields Pharmaceuticals in PC and PP syringes. Bevacizumab from the stored syringes was analysed at monthly time points for a 6-month period and compared with bevacizumab from a freshly opened vial at each time point. SDS-PAGE electrophoresis and size-exclusion chromatography (SEC) was used to observe aggregation and degradation. Dynamic light scattering (DLS) provided information about the hydrodynamic size and particle size distribution of bevacizumab in solution. VEGF binding and the active concentration of bevacizumab was determined by surface plasmon resonance (SPR) using Biacore.

RESULTS

SDS-PAGE and SEC analysis did not show any changes in the presence of higher molecular weight species (HMWS) or degradation products in PC and PP syringes from T0 to T6 compared with bevacizumab sampled from a freshly opened vial. The hydrodynamic diameter of bevacizumab in the PC syringe after 6 months of storage was not significantly different to bevacizumab taken from a freshly opened vial. Using SPR, the VEGF binding activity of bevacizumab in the PC syringe was comparable to bevacizumab taken from a freshly opened vial.

CONCLUSION

No significant difference over a 6-month period was observed in the quality of bevacizumab repackaged into prefilled polycarbonate and polypropylene syringes when compared with bevacizumab that is supplied from the vial.

Scientific and Regulatory Policy Committee Points-to-consider Paper*

Drug-induced vascular injury (DIVI) is a recurrent challenge in the development of novel pharmaceutical agents. Although DIVI in laboratory animal species has been well characterized for vasoactive small molecules, there is little available information regarding DIVI associated with biotherapeutics such as peptides/proteins or antibodies. Because of the uncertainty about whether DIVI in preclinical studies is predictive of effects in humans and the lack of robust biomarkers of DIVI, preclinical DIVI findings can cause considerable delays in or even halt development of promising new drugs. This review discusses standard terminology, characteristics, and mechanisms of DIVI associated with biotherapeutics. Guidance and points to consider for the toxicologist and pathologist facing preclinical cases of biotherapeutic-related DIVI are outlined, and examples of regulatory feedback for each of the mechanistic types of DIVI are included to provide insight into risk assessment.

Anterior chamber paracentesis might prevent sustained intraocular pressure elevation after intravitreal injections of ranibizumab for age-related macular degeneration

BACKGROUND/AIMS

To evaluate the efficacy of anterior chamber paracentesis for preventing sustained intraocular pressure (IOP) elevation after intravitreal ranibizumab (IVR) injections for age-related macular degeneration (AMD).

METHODS

The medical records for all cases of exudative AMD treated with IVR injections and followed monthly for 12 months or longer were reviewed retrospectively. Anterior chamber paracentesis was performed just before IVR injections. A sustained IOP elevation was defined as 22 mm Hg or higher during 2 consecutive visits with an increase exceeding 6 mm Hg from baseline.

RESULTS

One hundred and eleven eyes met the inclusion criteria, and none of these eyes had a sustained IOP elevation.

CONCLUSIONS

Anterior chamber paracentesis before IVR injections may prevent sustained IOP elevations.