REBEL: Effect of Ranibizumab Versus Bevacizumab on the Macular Perfusion in Diabetic Macular Edema

Sponsor

Cairo University (Other)

Overall Status

Recruiting

CT.gov ID

NCT04991350

Collaborator

(none)

Enrollment

Location

Arms

11.2

Anticipated Duration (Months)

Patients Per Site Per Month

Study Details

Study Description

Brief Summary

The Early Treatment Diabetic Retinopathy Study (ETDRS) group founded guidelines for treating patients with clinically significant diabetic macular edema (DME) with focal/grid macular laser photocoagulation. Since then, macular laser, and steroids, were the main therapies for the treatment of DME until anti-vascular endothelial growth factors (anti-VEGF) drugs were developed after a growing body of scientific evidence implicated VEGF in the pathophysiologic process of DME.

Anti-VEGF drugs have been implicated in the treatment of DME. VEGF has been shown to play an important role in the occurrence of increased vascular permeability in DME. VEGF levels are significantly higher in patients with DME and extensive leakage than in patients with minimal leakage.

Many studies such as Diabetic Retinopathy Clinical Research [DRCR] Network studies, RESTORE Study, RISE and RIDE Research Group, and The BOLT Study have supported the use of anti-VEGF agents in the treatment of DME with better visual outcomes using anti-VEGF injections alone or in combination with other treatments.

Several ocular complications of intravitreal anti-VEGF injections have been reported including endophthalmitis, cataract, and retinal detachment. The different effects on macular perfusion between different anti-VEGFs have yet to be fully concluded with mixed conclusions that it increases or decreases or has no effect on perfusion of the macula in response to Anti-VEGF treatment. In many of these studies, however, patients with more ischemic retinas were not included. Retinal ischemia is a vital factor determining the diabetic retinopathy progression and prognosis.

Optical coherence tomography angiography (OCTA) detects blood flow by analyzing signal decorrelation between two sequential OCT cross-sectional scans at the same location. As it detects the movements of red blood corpuscles within the vessels, compared to the stationary retinal surroundings, which will result in signal disparity and imaging The split-spectrum amplitude-decorrelation angiography (SSADA) algorithm improves the signal to noise ratio. OCTA is considered a reliable tool in the detection and quantification of macular ischemia in diabetics.

In this study, the investigators aim to compare the effect of repeated intravitreal injections of ranibizumab and bevacizumab on the perfusion of different capillary layers in the macula of diabetic patients using OCTA.

Condition or Disease	Intervention/Treatment	Phase
Diabetic Macular Edema Macular Ischemia Diabetic Retinopathy Vascular Endothelial Growth Factor Overexpression	Drug: Intravitreal ranibizumab Drug: Intravitreal bevacizumab	Phase 4

Detailed Description

Diabetic retinopathy is the major cause of blindness in developed but also in developing countries. The disruption of the blood-retinal barrier and the subsequent accumulation of fluid in the intraretinal layers result in diabetic macular edema (DME), the leading cause of central vision loss in these patients.

The Early Treatment Diabetic Retinopathy Study (ETDRS) group founded guidelines for treating patients with clinically significant DME (CSME) with focal/grid macular laser photocoagulation. Since then, macular laser, and steroids, were the main therapies for treatment of DME until anti-vascular endothelial growth factors (anti-VEGF) drugs were developed after a growing body of scientific evidence implicated VEGF in the pathophysiologic process of DME.

DRCR network protocol T found statistically insignificant difference between ranibizumab and bevacizumab on visual acuity and central macular thickness in diabetic macular edema.

Several ocular complications of intravitreal anti-VEGF injections have been reported including endophthalmitis, cataract, and retinal detachment. The different effects on macular perfusion between different anti-VEGFs have yet to be fully concluded with mixed conclusions that it increases or decreases or has no effect on perfusion of macula in response to Anti-VEGF treatment.in many of these studies, however, patients with more ischemic retinas were not included. Retinal ischemia is a vital factor determining the diabetic retinopathy progression and prognosis.

Using ocular ultrasound some studies showed retinal arteriolar vasoconstriction in eyes treated with anti-VEGF, while others showed decreased blood flow velocities in all retro-bulbar arteries after intravitreal injection of anti-VEGF. This may indicate that anti-VEGF may have an effect on ocular perfusion.

Fluorescein angiography (FA) was the method used to assess changes in macular perfusion after anti-VEGF injections in most of the studies. Despite its clinical value, however, FA is known to have documented risks. Optical coherence tomography angiography (OCTA) is an excellent non-invasive modality to acquire high-resolution images of the retinal vasculature that can be utilized in the treatment of retinal disease without the need for dye injection. It allows the visualization of both the superficial and deep retinal capillary layers separately and the construction of microvascular flow maps.

OCTA detects blood flow by analyzing signal decorrelation between two sequential OCT cross-sectional scans at the same location. As it detects the movements of red blood corpuscles within the vessels, compared to the stationary retinal surroundings, which will result in signal disparity and imaging The split-spectrum amplitude-decorrelation angiography (SSADA) algorithm improves the signal to noise ratio. OCTA is considered a reliable tool in the detection and quantification of macular ischemia in diabetics.

Study Design

Study Type:

Interventional

Anticipated Enrollment :

56 participants

Allocation:

Randomized

Intervention Model:

Parallel Assignment

Masking:

Double (Participant, Outcomes Assessor)

Primary Purpose:

Treatment

Official Title:

Comparison of the Effect of Ranibizumab Versus Bevacizumab on the Macular Perfusion in Diabetic Macular Edema Using OCTA

Actual Study Start Date :

Nov 26, 2021

Anticipated Primary Completion Date :

Sep 1, 2022

Anticipated Study Completion Date :

Nov 1, 2022

Arms and Interventions

Arm	Intervention/Treatment
Active Comparator: Ranibizumab Group Patients will receive monthly ranibizumab injections for 3 months.	Drug: Intravitreal ranibizumab Intravitreal injection of 0.3 mg/0.05 ml ranibizumab will be performed monthly for 3 months. Other Names: Lucentis
Active Comparator: Bevacizumab Group Patients will receive monthly bevacizumab injections for 3 months.	Drug: Intravitreal bevacizumab Intravitreal injection of 1.25 mg/0.05 ml bevacizumab will be performed monthly for 3 months. Other Names: Avastin

Arm

Intervention/Treatment

Active Comparator: Ranibizumab Group

Patients will receive monthly ranibizumab injections for 3 months.

Drug: Intravitreal ranibizumab

Intravitreal injection of 0.3 mg/0.05 ml ranibizumab will be performed monthly for 3 months.

Other Names:

Lucentis

Active Comparator: Bevacizumab Group

Patients will receive monthly bevacizumab injections for 3 months.

Drug: Intravitreal bevacizumab

Intravitreal injection of 1.25 mg/0.05 ml bevacizumab will be performed monthly for 3 months.

Other Names:

Avastin

Outcome Measures

Primary Outcome Measures

Change in foveal avascular zone area [0 and 3 months.]
The change in the foveal avascular zone area will be compared between the two treatment arms as a measure of macular perfusion change.
Change in vascular density of the superficial retinal capillary plexus [0 and 3 months.]
The change in the superficial retinal capillary plexus vascular density will be compared between the two treatment arms as a measure of macular perfusion change.
Change in vascular density of the deep retinal capillary plexus [0 and 3 months.]
The change in the deep retinal capillary plexus vascular density will be compared between the two treatment arms as a measure of macular perfusion change.

Secondary Outcome Measures

Change in best corrected visual acuity [0 and 3 months]
The change in best corrected visual acuity will be assessed following treatment with both drugs using standard Snellen charts.
Change in central macular thickness [0 and 3 months]
The change in central macular thickness will be assessed following treatment with both drugs using optical coherence tomography.
Change in intraocular pressure [0 and 3 months]
he change in intraocular pressure will be assessed following treatment with both drugs using Goldman applanation tonometry.
Change of severity of diabetic retinopathy [0 and 3 months]
The change in the severity of diabetic retinopathy will be assessed following treatment with both drugs using color fundus photographs and clinical examination.

Eligibility Criteria

Criteria

Ages Eligible for Study:

18 Years and Older

Sexes Eligible for Study:

All

Accepts Healthy Volunteers:

Inclusion Criteria:

Patients ≥18 years old with type 1 or 2 diabetes mellitus with decreased BCVA due to center involving diabetic macular edema on spectral-domain optical coherence tomography.
Patients with central macular thickness "CMT" of ≥ 300 micrometers

Exclusion Criteria:

Ocular conditions that may affect macular perfusion (e.g. retinal vascular diseases, uveitis, vasculitis etc.)
History of vitreo-retinal surgeries.
Previous macular laser treatment
Presence of epi-retinal membrane involving the macula or vitreo-macular traction.
Media opacity preventing good image quality.
Uncontrolled glaucoma.
Thrombo-embolic events within 6 months
Previous intravitreal injections of anti-VEGF