Intravitreal DEX Implant for the Treatment of Diabetic Macular Edema: A Review of National Consensus

Diabetic macular edema (DME)'s therapeutic approach can frequently be challenging. The purpose of the review is to propose evidence-based recommendations on the employment of intravitreal dexamethasone implants (DEX) when approaching patients suffering from DME. Seven national consensuses redacted by different groups of retina specialists from Europe and Asia were examined and confronted. Each consensus was redacted utilizing a Delphi approach, in person meetings, or by reviewing the literature. DEX can be studied as a first-line strategy in individuals suffering from DME with inflammatory OCT biomarkers, in vitrectomized eyes, in patients with recent cardiovascular events, in pregnant women, in patients scheduled to undergo cataract surgery or with poor compliance. The other parameters considered were the indications to the DME treatment, when to switch to DEX, the definition of non-responder to anti-VEGFs agents and to the DEX implant, whether to combine DEX with laser photocoagulation, the association between glaucoma and DEX, and the management of DEX and the cataract. Although several years have passed since the introduction of DEX implants in the DME treatment, there is still not a unified agreement among retina specialists. This paper compares the approach in the DME treatment between countries from different continents and provides a broader and worldwide perspective of the topic.

Management of Diabetic Macular Edema: Guidelines from the Emirates Society of Ophthalmology

In the United Arab Emirates, retinopathy has been shown to be present in 19% of the diabetic population, with diabetes identified in up to 40% of individuals aged over 55 years. Despite the prevalence of diabetic retinal diseases, there are no unified national guidelines on the management of diabetic macular edema (DME). These published guidelines are based on evidence taken from the literature and published trials of therapies, and consensus opinion of a representative expert panel with an interest in this condition, convened by the Emirates Society of Ophthalmology. The aim is to provide evidence-based, clinical guidance for the best management of different aspects of DME, with a special focus on vision-threatening diabetic retinopathy. Treatment should be initiated in patients with best-corrected visual acuity 20/30 or worse, and/or features of DME as seen on optical coherence tomography (OCT) with central retinal thickness (CRT) of at least 300 μm or in symptomatic patients with vision better than 20/25, and/or CRT less than 300 μm where there are OCT features consistent with center-involving macular edema. The treatment of DME is effective irrespective of glycated hemoglobin (HbA1c) level, and treatment must not be denied or delayed in order to optimize systemic parameters. All ophthalmic treatment options should be discussed with the patient for better compliance and expectations. Non-center-involving DME can be initially observed until progression toward the center is documented. Macular laser no longer has a primary role in center-involving DME, and anti-vascular endothelial growth factor (anti-VEGF) therapy should be considered as first-line treatment for all patients, unless contraindicated. If anti-VEGF is contraindicated, a steroid dexamethasone implant can be considered for first-line treatment. Recommendations for the treatment of DME in special circumstances and in relapsing and refractory DME are also discussed.

Vascular endothelial growth factor-A level in human breast milk after intravitreal injection of ranibizumab: a case report

Background

Ranibizumab is one of intravitreal anti-vascular endothelial growth factor agents. It is applied in the treatments of choroidal neovascularization, age-related macular degeneration, diabetic macular edema, and macular edema secondary to retinal vein occlusion. Preliminary evidence suggests that intravitreal ranibizumab may enter the plasma and human breast milk in very low-level concentration. As a precaution, breastfeeding is not recommended during the treatment of intravitreal injection of ranibizumab. There are limited data regarding the change of anti-vascular endothelial growth factor concentration in human breast milk after intravitreal injection of ranibizumab, especially in the first 24 h after injection. The purpose of this report is to analyse the concentration change of vascular endothelial growth factor-A in human breast milk with time, in the short term after intravitreal injection of ranibizumab.

Case presentation

In June 2018, a 30-year-old patient breastfeeding a six-month-old baby was diagnosed with choroidal neovascularization of left eye in Eye Hospital of Wenzhou Medical University. She received four administrations of 0.5 mg intravitreal injection of ranibizumab of the left eye, and breast milk was collected just before the injection, and 1–3, 6, 12, 24, 48, and 72 h after intravitreal injection, and assessed for vascular endothelial growth factor-A concentration. The change in vascular endothelial growth factor-A concentration in human breast milk showed the same trend after each injection, decreasing significantly within 6–12 h (about 20–30% lower), and increasing to pre-injection level by 24 h after injection.

Conclusions

The concentration of vascular endothelial growth factor-A in human breast milk of a mother who continues lactating dropped initially and rose to pre-injection level about 24 h after intravitreal injection of ranibizumab. The data may offer more information to evaluate the impact of anti-vascular endothelial growth factor agent intravitreal injection of lactating mothers and their breastfed infants.

Intravitreal Conbercept for Idiopathic Choroidal Neovascularization in Nursing Women

Purpose: To report the clinical course and vascular endothelial growth factor (VEGF) levels in breast milk among three nursing women diagnosed with idiopathic choroidal neovascularization (CNV) before and after intravitreal injection of conbercept. Methods: This was an observational case series. The main outcomes and measures included best-corrected visual acuity (BCVA), anatomical features using optical coherence tomography, and breast milk concentrations of VEGF before and after the intravitreal injection of conbercept. Results: BCVA was increased, and no ocular or systemic safety problems were observed in any of the three patients during the follow-up period. An enzyme-linked immunosorbent assay was used to measure VEGF concentrations in the breast milk samples. Samples were collected 1 day before and 1, 7, and 30 days after the first intravitreal injection of conbercept. After conbercept injection, VEGF levels in breast milk were slightly decreased and did not change significantly in the following week; levels recovered fully by 30 days post-treatment. Conclusions: Intravitreal injection of conbercept shows favorable effectiveness and safety in the treatment of idiopathic CNV in nursing women and does not result in a significant reduction in VEGF in human breast milk.

Transfer of monoclonal antibodies into breastmilk in neurologic and non-neurologic diseases

Objective

To review currently available data on the transfer of monoclonal antibodies (mAbs) in the breastmilk of women receiving treatment for neurologic and non-neurologic diseases.

Methods

We systematically searched the medical literature for studies referring to 19 selected mAb therapies frequently used in neurologic conditions and “breastmilk,” “breast milk,” “breastfeeding,” or “lactation.” From an initial list of 288 unique references, 29 distinct full-text studies met the eligibility criteria. One additional study was added after the literature search based on expert knowledge of an additional article. These 30 studies were reviewed. These assessed the presence of our selected mAbs in human breastmilk in samples collected from a total of 155 individual women.

Results

Drug concentrations were typically low in breastmilk and tended to peak within 48 hours, although maximum levels could occur up to 14 days from infusion. Most studies did not evaluate the breastmilk to maternal serum drug concentration ratio, but in those evaluating this, the highest ratio was 1:20 for infliximab. Relative infant dose, a metric comparing the infant with maternal drug dose (<10% is generally considered safe), was evaluated for certolizumab (<1%), rituximab (<1%), and natalizumab (maximum of 5.3%; cumulative effects of monthly dosing are anticipated). Importantly, a total of 368 infants were followed for ≥6 months after exposure to breastmilk of mothers treated with mAbs; none experienced reported developmental delay or serious infections.

Conclusions

The current data are reassuring for low mAb drug transfer to breastmilk, but further studies are needed, including of longer-term effects on infant immunity and childhood development.

BEVACIZUMAB LEVELS IN BREAST MILK AFTER LONG-TERM INTRAVITREAL INJECTIONS

PURPOSE

The purpose of this study is to determine whether bevacizumab is detectable in the breast milk of nursing mothers.

METHODS

Breast milk samples were collected from 2 patients receiving monthly intravitreal bevacizumab injections for choroidal neovascularization over the course of 16 months. Enzyme-linked immunosorbent assay and Western blot analysis was used to determine the levels of bevacizumab in the milk samples.

RESULTS

An enzyme-linked immunosorbent assay was developed using antibodies specific to bevacizumab in which the sensitivity threshold was 3 ng/mL. All breast milk samples assayed from the two patients actively undergoing treatment did not have detectable levels of bevacizumab. Samples collected 1.5 hours and 7 hours after an injection and 2 randomly chosen samples were negative by Western blot analysis.

CONCLUSION

A sensitive assay to detect bevacizumab in breast milk samples assayed suggests that intravitreal injections do not result in detectable bevacizumab in breast milk.

Pharmacokinetics, pharmacodynamics and pre-clinical characteristics of ophthalmic drugs that bind VEGF

Drugs that prevent the binding of VEGF to its trans-membrane cognate receptors have revolutionized the treatment of the most important chorioretinal vascular disorders: exudative age-related macular degeneration, diabetic macular edema, and retinal vein occlusions. Pegaptanib, which binds to VEGF165 and longer isoforms, ranibizumab and bevacizumab, which bind all VEGF-A isoforms, and aflibercept, which binds VEGF-A, VEGF-B, and placental growth factor, all bind VEGF165 with high affinity. The drugs have relatively long half-lives (7 to 10 days) after intravitreal depot injections and clinical durations of action that usually exceed 4 weeks. Plasma VEGF concentrations decrease after intravitreal injections of bevacizumab and aflibercept because their systemic half-lives are extended by their Fc fragments. Extensive in vitro and in vivo testing shows that the drugs prevent VEGF-mediated activation of endothelial cells while exhibiting little evidence of toxicity. Further anti-VEGF drug development is on-going.