NEW YORK (Reuters Health) – In patients with diabetic macular edema, repeated ranibizumab injections are not associated with impaired macular perfusion and can be safely offered even to those with severe microangiopathy and advanced capillary dropout, researchers say.
“Diabetic retinopathy is a common complication in diabetic patients. Elevated blood sugar levels are harmful for capillary walls, leading to microangiopathy and capillary closure,” Dr. Blanca Gerendas of Medical University Vienna in Austria said in an email to Reuters Health.
While anti-vascular endothelial growth factor (anti-VEGF) treatment is the first-line therapy for center-involving macular edema, data on capillary perfusion changes during repeated treatment in patients whose vascular network may be compromised are “limited,” according to Dr. Gerendas and colleagues.
To investigate, the team conducted a post-hoc analysis of prospectively gathered data from patients with diabetic macular edema who participated in the 12-month RESTORE core study and the 24-month open label RESTORE extension study.
Of 345 patients (mean age, 63; 59% men; 95% white) with center-involving macular edema in the core study, 240 entered the extension study, including 83 (35%) who received 0.5 mg intravitreal ranibizumab; 83 (35%) who received 0.5 mg intravitreal ranibizumab and laser combination therapy; and 74 (31%) who received laser monotherapy (with sham ranibizumab) in the first year of the study.
All patients in the extension study were eligible for 0.5 mg intravitreal ranibizumab and laser treatment, regardless of their previous treatment assignment; 208 (87%) patients completed that study.
As reported online March 1 in JAMA Ophthalmology, all participants in both studies underwent fluorescence angiography twice yearly to assess severity of capillary loss in the parafoveal area; regularity of the foveal avascular zone outline; and the size of the foveal avascular zone.
At baseline, 43% of patients had definitive altered foveal avascular zone regularity and 49% had questionably altered regularity. In addition, 27% had definitive capillary loss.
The mean foveal avascular zone size at baseline was 0.261 mm2 in patients taking ranibizumab monotherapy; 0.231 mm2 in those taking ranibizumab and laser combination therapy; and 0.201 mm2 in those on laser monotherapy.
No significant increase in foveal avascular zone site was seen in any of the groups at any time during the study. At 36 months, nonsignificant increases had occurred in those taking ranibizumab, with mean increases of 0.073 mm2 for those on monotherapy and 0.117 mm2 for combination therapy.
No changes in foveal avascular zone regularity occurred any treatment group, and no differences were found in capillary loss around the fovea.
Dr. Gerendas concluded, “Within three years, repeated ranibizumab injections seemed to be safe even in previously compromised capillary beds.”
Dr. Paul Sternberg, chairman of the Vanderbilt Eye Institute in Nashville, Tennessee, told Reuters Health, “This is a very good study that provides important reassurances for physicians and patients when ranibizumab is being considered for treatment of diabetic macular edema.”
“The benefit of this agent in treating macular edema is well established,” he said by email. “However,” he added, “there was concern that an anti-VEGF agent that reduces vascular leakage leading to macular edema may also compromise macular capillary blood flow in eyes where there already was some reduction due to the damaged retinal capillaries in diabetic retinopathy.”
“Fortunately, that does not appear to be the case (and so) this will expand the indications for this treatment,” Dr. Sternberg concluded.
The study was funded by Novartis Aktiengesellschaft. One coauthor is a Novartis Ireland employee and two receive funds from Novartis.
SOURCE: http://bit.ly/2Fnd5wU
JAMA Ophthalmol 2018.
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