Intraocular Bevacizumab Compared With Intraocular Triamcinolone in Patients With Diabetic Macular Edema — TRIASTIN  

Diabetic Macular Edema Clinical Trial

Official title: A Randomized, Double-masked Study With Intraocular Anti-VEGF (Avastin®/Lucentis®) Compared With Intraocular Triamcinolone (Volon A®) in Patients With Clinical Significant Diabetic Macular Edema

Status Recruiting

Clinical Trial Summary

The purpose of this study is to investigate the change in macular edema and the absolute change in visual acuity following intravitreal administered injections of Bevacizumab (Avastin®) or Ranibizumab (Lucentis®) compared with Triamcinolone (Volon A®) in patients with clinical significant diabetic macular edema.

The investigators monitor the change in macular edema measured with standard optical coherence tomography (OCT) and the absolute change in visual acuity analyzed by standardized charts according to the protocol used in the Early Retreatment in Diabetic Retinopathy Study (ETDRS).

Clinical Trial Description

Diabetes mellitus is the most common endocrine disease in developed countries, with prevalence estimates ranging between 2 to 5% of the world's population. Diabetic retinopathy and diabetic macular edema are common microvascular complications in diabetic patients and may lead to decreasing of visual acuity, eventually to blindness. The Wisconsin Epidemiologic Study found an incidence of macular edema of 20.1% in the younger-onset group and of 14 to 25% in patients with type 2 diabetes mellitus over a period of 10 years.

Diabetic macular edema is characterized by the accumulation of extracellular fluid in Henle´s layer and the inner nuclear layer of the retina. There pathogenesis involves the interaction of several factors: the breakdown of the blood-retinal-barriers, production of biochemical factors, tissue hypoxia, retinal circulatory changes and vitreous tractions.

Laser photocoagulation is the most common treatment modality for diabetic macular edema. Perifoveal focal/grid laser coagulation was found to be effective saving the visual acuity in only 50% of patients with diabetic macular edema and just 3-14% of treated patients had an improved visual acuity post-operatively. The decent results of laser coagulation are associated with potential side effects as paracentral scotomas[4], change of color discrimination, development of epiretinal gliosis and subretinal fibrosis and expansion of laser scar size.

In the past few years, several studies investigating the effect of intravitreal steroids such as triamcinolone in patients with diabetic macular edema found a significant reduction in macular edema. Therefore intravitreal steroids have become part of standard therapy in the treatment of diabetic macular edema.

Furthermore, some studies showed that the vascular endothelial growth factor (VEGF) is the major angiogenic stimulus responsible for increase of vasopermeability, cell proliferation and angiogenesis in diabetic retinopathy (DRP). Evaluation of VEGF levels in the vitreous have indicated a role for VEGF in diabetic macular edema: vitreous samples of patients with diabetic macular edema contain elevated VEGF concentration and injection of VEGF in experimental studies led to breakdown of the blood-retina barrier.

Not only in age-related macular degeneration but also in other diseases like in diabetic macular edema we can find an increasing evidence for a therapeutic role of anti-VEGF drugs. Intravitreal injections have become the most favored treatment procedure for administering anti-VEGF drugs.

The side effects and the modest results of laser treatment on the visual acuity in diabetic macular edema led to studies using anti-VEGF therapy. Unpublished study results on the aptamer pegaptanib (Macugen®) are promising. A study using the antibody fragment Ranibizumab (Lucentis®) is in progress.

Currently there is one anti-VEGF drug already on the market: Bevacizumab (Avastin®), which has approved as intravenous infusion for the treatment of metastatic colo-rectal cancer. Previous studies have shown that systemic use of Bevacizumab (Avastin®) can obtain very promising results on patients with choroidal neovascularisation (CNV) by age-related macular degeneration. This drug, a monoclonal full-length antibody, designed to bind all isoforms of VEGF, is a large molecule. But case reports in patients with CNV caused by age-related macular degeneration and with macular edema from central retinal vein occlusion indicate that intravitreally given Bevacizumab (Avastin™) is effective in diseases originating from the choroids and also the retina. These findings imply a sufficient penetration of the retina by Bevacizumab (Avastin®).

A recent study investigating the effect of intravitreal bevacizumab (Avastin®) in patients with diabetic macular edema found a significant reduction in macular edema.

Based on these new findings and the important role of VEGF in diabetic macular edema and in proliferative diabetic retinopathy, we propose a double-masked, randomised pilot study for treatment of diabetic macular edema with intravitreally administered anti VEGF (Avastin®/Lucentis®) compared with intravitreally administered triamcinolone (VolonA®). ;

Study Design

Allocation: Randomized, Endpoint Classification: Safety/Efficacy Study, Intervention Model: Parallel Assignment, Masking: Double Blind (Subject, Caregiver, Investigator), Primary Purpose: Treatment

Related Conditions & MeSH terms

• Diabetic Macular Edema
• Edema
• Macular Edema

• NCT number: NCT00682539
• Study type: Interventional
• Source: Medical University of Vienna
• Contact: Georg Rainer, MD
• Phone: 43-40-400
• Email: georg.rainer@meduniwien.ac.at
• Status: Recruiting
• Phase: Phase 4
• Start date: October 2007
• Completion date: December 2014