Effects of Two Different Doses of Ranibizumab on Diabetic Retinopathy Severity and Progression in the Ranibizumab for Edema of the Macula in Diabetes (READ-3) Study

Abstract

Purpose : To evaluate the effects of two different doses of Ranibizumab (0.5mg and 2.0mg) on severity of diabetic retinopathy (DR) in patients with diabetic macular edema (DME).

Methods : In the READ-3 study, patients with DME received six mandatory monthly intravitreal injections of either 0.5 or 2.0mg of ranibizumab (RBZ) followed by as needed (PRN) injections until month 24. The main outcome measure of this sub-study was to assess the effects of two different doses of ranibizumab on the grade of DR in the study eye. Inclusion criterion included completion of month 24 visits and availability of gradable seven-field fundus photographs at baseline and month 24 visits. Fundus photographs were analyzed at the two visits by a central reading center. Diabetic retinopathy severity scale (DRSS) scores were assessed using the Early Treatment Diabetic Retinopathy Study (ETDRS) severity scale. Participants with a history of pan retinal photocoagulation (PRP) were assigned to a minimum severity level of 60. Frequencies of change in severity of DR were compared using the chi-square test and the Fisher exact test.

Results : 152 eyes (152 patients) were randomized in the READ-3 study. 70 eyes (70 patients) met above inclusion criteria and were thus analyzed. There were 43 eyes in the 0.5mg group and 27 eyes in the 2.0mg group. A total of 28 eyes (40%; 18 in 0.5mg and 10 in 2.0mg) had a history of prior PRP. At 24 months, 33.3% eyes (groups combined) showed a ≥2-step reduction in the DRSS score. Forty percent (40%) of eyes in the low dose group (0.5mg) and 23.5 % of patients in the high dose group (2.0mg) showed a ≥2-step reduction in the DRSS score. The difference between the two doses was not significant (p=0.51). None of the patients demonstrated worsening of DR status or developed any complications of the disease.

Conclusions : Both high-dose and low-dose intravitreal RBZ can lead to reduction in degree and progression of DR in patients with DME. High-dose RBZ does not appear to provide additional benefit over 0.5 mg RBZ in improving DR.

This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.