Purpose of review

Nearly 20 years ago, vascular endothelial growth factor (VEGF)inhibitors (VEGFi) were adapted from systemic use from antiangiogenesis roles to intravitreal uses. Initially bevacizumab a murine immunoglobulin was injected 'off label' as a treatment for diabetic macular edema and age-related macular degeneration. Throughout the following decade aflibercept and finally ranibizumab were adapted and obtained Food and Drug Administration approval for intravitreal use. Initially systemic absorption was thought to be quite low after intravitreal injections and was quoted as being 200-fold lower than levels postulated to induce significant VEGF inhibition. Pharmacodynamic studies obtained in 2014 and again in 2017 revealed significant systemic absorption and detectable VEGF inhibition, this has since been confirmed in multiple subsequent studies.

Recent findings

A few case reports of renal dysfunction and glomerular disease related to VEGFi were initially identified. Mixed findings on effects on blood pressure were noted in studies. More recently, 32 cases of de-novo glomerular disease and/or proteinuria exacerbation were identified. New studies have corroborated increased blood pressure, proteinuria exacerbation in patients with pre-existing nephrotic syndrome, and systemic VEGF depletion. Further, the most common lesion of systemic VEGFi nephrotoxicity, thrombotic microangiopathy, has recently been reported by our group.

Summary

We will review the pharmacokinetic, translational, and epidemiological data that year upon year establish the finite-yet real risk of intravitreal VEGFi.

Scleroderma renal crisis is a serious complication that can develop in certain patients with systemic sclerosis. Some risks have been identified as potential triggers of scleroderma renal crisis, including the high-dose oral corticosteroids. Here, we present a patient who developed clinically severe systemic sclerosis and scleroderma renal crisis after exposure to oral corticosteroids and intravitreal vascular endothelial growth factor blockade with bevacizumab for cotton wool spots. The patient's scleroderma renal crisis was severe, progressive, and refractory to the standard of care therapy: oral captopril. Biopsy showed a diffuse thrombotic microangiopathy and findings consistent with scleroderma renal crisis. We hypothesize that depletion of systemic vascular endothelial growth factor with intravitreal anti-vascular endothelial growth factor injections likely contributed to the particularly severe presentation seen in this case. Though the finding of a monoclonal gammopathy of undetermined significance is another complicating factor, this case suggests that vascular endothelial growth factor inhibition may be a newly recognized trigger of scleroderma renal crisis.

Vascular endothelial growth factor (VEGF) inhibition can cause worsening hypertension, proteinuria, chronic kidney injury, and glomerular disease. Thrombotic microangiopathy (TMA) and other nephrotic disorders have been reported with systemic VEGF blockade. These same agents are given intravitreally for age-related macular degeneration (AMD) and diabetic retinopathy (DR), albeit at lower doses than those given for systemic indications. Systemic absorption of anti-VEGF agents when given intravitreally has been shown consistently along with evidence of significant intravascular VEGF suppression. While worsening hypertension has only been seen in some large-scale studies, case reports show worsening proteinuria and diverse glomerular diseases. These include TMA-associated lesions like focal and segmental glomerulosclerosis with collapsing features (cFSGS). In this paper, we report three cases of TMA likely associated with the use of intravitreal anti-VEGF therapy. These patients developed the signature lesion of VEGF blockade in a 6 to 11 month time frame after starting intravitreal VEGF inhibitors. The literature is reviewed showing similar cases. Intravitreal VEGF blockade may cause these adverse events in a hitherto unidentified subgroup of patients. Well-controlled prospective observational trials are needed to determine the event rate and identify which subgroups of patients are at increased risk. A registry for patients who develop worsening hypertension, proteinuria exacerbation, and glomerular diseases from intravitreal VEGF blockade is proposed.