NEW YORK (Reuters Health) – Adding dexamethasone to continued ranibizumab treatment reduces retinal thickness but does not improve vision in patients with persistent diabetic macular edema (DME), according to results from a phase 2 randomized trial.
Intravitreous injections of anti-vascular endothelial growth factor (VEGF) agents like ranibizumab improve visual acuity and limit retinal thickening in eyes with DME, but edema and reduced visual acuity persist in as many as 66% of eyes treated with at least six monthly injections.
Danni Liu from the Jaeb Center for Health Research, in Tampa, Florida, and colleagues in the Diabetic Retinopathy Clinical Research Network compared continued ranibizumab therapy alone versus continued ranibizumab plus intravitreous dexamethasone. Their study included 129 eyes of 116 patients (median age, 65) with persistent DME and reduced visual acuity despite previous anti-VEGF therapy.
The findings were published online November 11 in JAMA Ophthalmology and presented at the American Academy of Ophthalmology Meeting in New Orleans.
At 24 weeks, mean visual acuity letter scores did not differ between the combination group and the ranibizumab group, and there was no significant difference in the mean improvement in visual acuity between the groups.
There was no significant difference in the percentage of eyes that improved by 10 letters or more. However, significantly more eyes in the combination group (seven eyes, 11%) than in the ranibizumab group (one eye, 2%) showed improvements of 15 letters or more at 24 weeks; 13% of eyes in the combination group and 6% in the ranibizumab group lost 10 letters or more (P=0.09).
More eyes in the combination group (52%) than in the ranibizumab group (31%) had normal retinal central subfield thickness (CST), and the improvements in CST over 24 weeks were greater with combination therapy than with ranibizumab therapy.
There were no cases of endophthalmitis, but more eyes in the combination group (19/65, 29%) than in the ranibizumab group (0 eyes) experienced increased intraocular pressure (IOP) or initiated IOP-lowering eyedrops, and there were more post-randomization cataract extractions in the combination group (3/65, 5%) than in the ranibizumab group (0 eyes).
“The results from this study are consistent with previous trials of similar cohorts in which improvement in CST after switching to or adding corticosteroid treatment was greater but concomitant improvement in visual acuity was not greater than continued anti-VEGF treatment alone,” the researchers note.
Dr. Manuel S. Falcao from the University of Porto, in Portugal, who recently described the use of aflibercept in DME refractory to previous bevacizumab, told Reuters Health by email, “We do not know if the patients that were changed from bevacizumab to ranibizumab were the ones that improved visual acuity in the sham group.”
“Anti-VEGF agents are different, and some patients might have improved due to the change in anti-VEGF agent, so this is not really a true anti-VEGF resistance that was evaluated,” he said.
“It would be interesting to evaluate patients that were really resistant to all anti-VEGF therapy,” he said. “The switch in anti-VEGF agent may have biased the results.”
Dr. Falcao concluded that these findings “won’t change much of my clinical practice when I decide to combine therapy, but I know that the results will probably not be as good as I expected.”
Liu did not respond to a request for comment.
Genentech Inc. provided the ranibizumab, and Allergan Inc. provided the dexamethasone for the study. In addition, Allergan Inc. provided some funds to the Diabetic Retinopathy Clinical Research Network (DRCR.net) to defray the study’s clinical site costs. Genentech Inc. has provided funds restricted to DRCR.net clinical sites. Five of the 11 authors of this report had various relationships with Genentech, Allergan, or both.
SOURCE: http://bit.ly/2zMzRhU
JAMA Ophthalmol 2017.
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