Systemic and Ocular Safety of Intravitreal Anti-VEGF Therapies for Ocular Neovascular Disease

Biological, preclinical and clinical characteristics of inhibitors of vascular endothelial growth factors

Vascular endothelial growth factor (VEGF) plays an important role in the pathophysiology of several sight-threatening retinal disorders such as age-related macular degeneration, diabetic macular edema and proliferative diabetic retinopathy. The discovery of anti-VEGF agents has revolutionized our treatment of these conditions. There are 4 anti-VEGF agents that are either approved or in common use in ophthalmology, namely pegaptanib (Macugen, Pfizer), ranibizumab (Lucentis, Novartis), aflibercept or VEGF Trap-Eye (EYLEA, Bayer) and bevacizumab (Avastin, Roche). There are differences between them. In this review, the differences are discussed in detail. Furthermore, an attempt is made to explain some of the clinical trial data based on their differences in ocular efficacy, duration of action, and local and systemic safety concerns.

Insight into 144 patients with ocular vascular events during VEGF antagonist injections

AIM

To record ocular vascular events following injections of vascular endothelium growth factor (VEGF) antagonists.

METHODS

Collaborative multicenter case series (48 cases), literature reviews (32 cases), and reports to the FDA (64 cases) of patients that had vascular occlusions during anti-VEGF therapy were collected and analyzed.

RESULTS

A total of 144 cases of ocular vascular events were identified, with these diagnosed a median of 15 days after anti-VEGF injection. The majority of patients had pre-existing risk factors for cardiovascular events and nine patients had a prior history of glaucoma. Mean visual acuity dropped by 6.4 lines with severe visual loss after injection to NLP (five eyes), LP (six eyes), and HM (two eyes). The overall risk of ocular vascular events following a VEGF antagonist injection was 0.108% in the general population and 2.61% in the diabetic population. Mean retinal arterial constriction after intravitreal bevacizumab in 13 eyes was 21% (standard deviation = 27%), and mean retinal venous constriction was 8% (standard deviation = 30%).

CONCLUSION

Ocular vascular events are rare during anti-VEGF therapy, but can lead to severe visual loss and may be caused by a number of factors including the vasoconstrictor effect of the drug, a post-injection rise of intraocular pressure, patient stress as a result of the procedure, and the patient's natural history of underlying ocular or systemic diseases. The diabetic population appears to have a tendency towards ocular vascular occlusions.

Anti vascular endothelial growth factor sequential therapy for neovascular age-related macular degeneration: is this the new deal?

OBJECTIVE

To review clinical data on the sequential use of the non-selective vascular endothelial growth factor (VEGF) inhibitors (ranibizumab and bevacizumab) and the selective VEGF inhibitor (pegaptanib) in the treatment of neovascular age related macular degeneration (n-AMD).

METHODS

This is a selective review of the literature based on a PubMed search using the terms 'age-related macular degeneration', 'selective anti-VEGF', 'non-selective anti-VEGF' and 'combination therapy' from 2000 to date in the English language. Studies on the management of n-AMD reporting adherence, patient-reported outcomes, costs, side effects, resource use and cost effectiveness were also included.

RESULTS

The trial data suggest that pan-VEGF inhibition provides improved treatment outcomes in patients with n-AMD with selective anti-VEGF agents offering better tolerability on long-term treatment. A pilot trial and a large-scale, multicentre study confirmed the long-term efficacy of a selective VEGF inhibitor when used as maintenance therapy. Importantly, there is evidence that selective VEGF inhibition also reduces the risks associated with pan-VEGF blockade in patients with n-AMD.

DISCUSSION

Anti-VEGF agents play a principal role in the management of n-AMD. The most potent are the pan-VEGF agents although there is some discussion regarding their long-term tolerability. The sequential use of non-selective VEGF inhibitors as booster therapy with a selective VEGF inhibitor as maintenance therapy seems to offer a promising safety/efficacy profile, as well as improved cost/effectiveness.

Stanniocalcin-1 rescued photoreceptor degeneration in two rat models of inherited retinal degeneration

Oxidative stress and photoreceptor apoptosis are prominent features of many forms of retinal degeneration (RD) for which there are currently no effective therapies. We previously observed that mesenchymal stem/stromal cells reduce apoptosis by being activated to secrete stanniocalcin-1 (STC-1), a multifunctional protein that reduces oxidative stress by upregulating mitochondrial uncoupling protein-2 (UCP-2). Therefore, we tested the hypothesis that intravitreal injection of STC-1 can rescue photoreceptors. We first tested STC-1 in the rhodopsin transgenic rat characterized by rapid photoreceptor loss. Intravitreal STC-1 decreased the loss of photoreceptor nuclei and transcripts and resulted in measurable retinal function when none is otherwise present in this rapid degeneration. We then tested STC-1 in the Royal College of Surgeons (RCS) rat characterized by a slower photoreceptor degeneration. Intravitreal STC-1 reduced the number of pyknotic nuclei in photoreceptors, delayed the loss of photoreceptor transcripts, and improved function of rod photoreceptors. Additionally, STC-1 upregulated UCP-2 and decreased levels of two protein adducts generated by reactive oxygen species (ROS). Microarrays from the two models demonstrated that STC-1 upregulated expression of a similar profile of genes for retinal development and function. The results suggested that intravitreal STC-1 is a promising therapy for various forms of RD including retinitis pigmentosa and atrophic age-related macular degeneration (AMD).

Acute anterior uveitis following intravitreal bevacizumab but not subsequent ranibizumab

Purpose

Previous reports have identified noninfectious uveitis as a potential sequela following both intravitreal bevacizumab and ranibizumab injections. We present two unique cases of acute anterior uveitis following intravitreal bevacizumab that did not occur with subsequent ranibizumab injections.

Methods

Case report.

Conclusion

These cases may reflect differences in the etiology of anterior uveitis following intravitreal bevacizumab and ranibizumab. Given these differences, it may be reasonable to offer ranibizumab to patients who have experienced presumed bevacizumab-induced anterior uveitis.