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Topical NSAID shows no benefit in stalling progression to center-involved DME
After 12 months on a regimen of nepafenac 0.1%, eyes with non-center-involved DME worsened at a similar rate as eyes that received placebo.
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A DRCR.net study determined that after a year of therapy with topical nepafenac, eyes with non-center-involved diabetic macular edema were no less likely to progress to center-involved disease than non-treated eyes.
Prevalence data from the Centers for Disease Control suggest that many cases of DME do not involve the central macula, while data from the Early Treatment Diabetic Retinopathy Study and Protein Kinase C Inhibitor Study indicate that 20% to 30% of such cases may have center-involved DME by 1 year.
Current management of non-central DME is careful observation until the center of the macula thickens or it is perceived that the central subfield of the macula is threatened, according to the study.
The Diabetic Retinopathy Clinical Research Network (DRCR.net) conducted a multicenter, double-masked, randomized phase 2 clinical trial to assess whether topical nepafenac 0.1% three times daily for 1 year could prevent worsening of DME as seen on OCT and visual acuity outcomes.
“Topical nonsteroidals were not beneficial in reducing the incidence of center-involved DME from non-center-involved DME,” principal investigator Scott M. Friedman, MD, said of the study, whose key aspects were published in Retina.
Nepafenac is currently approved in the U.S. for the treatment of postoperative pain and inflammation associated with cataract surgery. It is approved in Europe for macular edema associated with cataract surgery in patients with diabetes.
DRCR.net protocol
Sixty-one subjects were randomized to receive nepafenac 0.1%, and 64 subjects were randomized to the placebo group. All participants had been deemed to be compliant with drop therapy in a run-in phase of the study. After 12 months, 57 participants remained in the nepafenac group and 60 remained in the placebo group.
“It is possible that better adherence would have resulted in a better outcome,” Friedman said. “It is difficult to reliably measure patient adherence with respect to using drops as prescribed.”
At baseline for all participants, mean visual acuity letter score was 83, mean time-domain equivalent retinal volume was 7.8 mm3, and mean time-domain equivalent central retinal subfield thickness was 223 µm.
Changes in retinal volume were –0.03 mm3 and 0.02 mm3 from baseline to 12 months in the nepafenac and placebo groups, respectively.
Center-involved DME developed in seven eyes in the nepafenac group (six phakic, one pseudophakic) and in nine eyes in the placebo group (seven phakic, two pseudophakic).
Before the 12-month visit, five eyes in the nepafenac group and three eyes in the placebo group underwent treatment for DME. At the 12-month visit, an additional five eyes in each group underwent DME treatment.
At month 12, mean letter score was 82 in the nepafenac group and 83 in the placebo group. Three eyes in the nepafenac group and two eyes in the placebo group lost 10 letters or more from baseline to the 12-month follow-up.
No eyes in either group had an increase in IOP of 10 mm Hg or more.
There were no differences between both groups in systemic adverse events.
Because the conversion rate was lower than expected, the study may have been underpowered, according to Friedman.
Macular edema after cataract surgery
Nepafenac may be limited to having a beneficial effect on macular edema associated with recent cataract surgery, the study said.
Friedman accounted for the difference in efficacy of nepafenac in treating macular edema after cataract surgery as a “different disease process [and] different mechanism of action.”
DRCR.net does not intend to conduct a larger phase 3 trial, Friedman said.
“Although there is anecdotal evidence of efficacy with topical nonsteroidals, there have not been any [randomized controlled trials] studying this,” he said. “At this time, the DRCR network is not interested in pursuing a larger phase 3 trial, although it always welcomes any new data on the use of nonsteroidals for the treatment or prevention of DME.” – by Kristie L. Kahl
- Reference:
- Friedman SM, et al. Retina. 2015;doi:10.1097/IAE.0000000000000403.
- For more information:
- Scott M. Friedman, MD, can be reached at Florida Retina Consultants, 2202 Lakeland Hills Blvd., Lakeland, FL 33805; email: smfriedman83@hotmail.com.
Disclosure: Friedman reports no relevant financial disclosures.