Ranibizumab reduces progression, severity of diabetic retinopathy
MedWire News: In patients with diabetic retinopathy (DR), two-year treatment with the vascular endothelial growth factor (VEGF) inhibitor ranibizumab reduces the risk for progression of the condition, show exploratory US study results.
Indeed, ranibizumab can even regress the severity of DR pathology over this period, say Michael Ip, from University of Wisconsin Fundus Photograph Reading Center in Madison, and colleagues.
The team remarks that while other specifically designed trials comparing outcomes of anti-VEGF therapy with panretinal photocoagulation (PRP; the current standard) are needed to confirm their results, the effects of ranibizumab in the study "are substantial."
A total of 759 patients with diabetic macular edema - a complication of both nonproliferative and proliferative DR - were randomly assigned to receive monthly sham, 0.3 mg ranibizumab, or 0.5 mg ranibizumab intravitreal injections.
The team graded patients' fundus photographs, taken at baseline and at 3-, 6-, 12-, 18-, and 24-month intervals, and performed clinical examinations. A 2- or 3-step change on the Early Treatment Diabetic Retinopathy Study (ETDRS) scale was the main outcome sought.
Over the entire study period, sham-treated patients' median DR severity remained moderately severe (47A-47D on the ETDRS where a higher score denotes more severe DR), whereas in the ranibizumab groups, DR severity improved (reduced) over time, observe the researchers.
Specifically, the proportion of mild nonproliferative DR (ETDRS levels 35A-35F) increased from 16% and 17% at baseline in the 0.3 mg and 0.5 mg treatment groups, to a respective 44% and 37% after two years. The corresponding change in the sham group was from 15% to 24%.
This modest improvement in the sham group is likely to be due to improved diabetic control or natural DR fluctuations, remark the researchers.
Patients treated with ranibizumab experienced significantly less DR worsening over the 24 months compared with their sham-treated counterparts, with significantly fewer eyes progressing by 2 or more or 3 or more steps on the ETDRS, write Ip and co-workers in Archives of Ophthalmology.
To control for patient-level changes, the researchers examined 2- and 3-step changes in non study eyes, and found no significant differences by treatment group.
After analysis by baseline DR severity, the research team found that among eyes with severe nonproliferative DR (ETDRS level 53E or higher), the percentage of patients during the study with 2 or more steps of improvement on the ETDRS was 6.8% in the sham group, 46.9% in the 0.3 mg ranibizumab group, and 46.8% in the 0.5 mg ranibizumab group.
Finally, adding the fundus photographs to their analysis, Ip et al found that by two years, the cumulative probability of DR progression was 33.8% of sham-treated study participants compared with 11.2% and 11.5% of participants in the 0.3 mg and 0.5 mg ranibizumab groups, respectively; a significant difference.
By Sarah Guy