VEGF Inhibitors Not Linked to Elevated IOP in Diabetic Macular Edema

Pam Harrison

September 04, 2013

TORONTO, Ontario — The incidence of elevated intraocular pressure (IOP) is low in patients with diabetic macular edema who have received repeated anti-VEGF injections for at least 1 year, new research shows.

"The literature continues to raise the question about whether there is an effect of anti-VEGF therapy, particularly ranibizumab, on elevated IOP," Suber Huang, MD, professor of ophthalmology at the Case Western Reserve University School of Medicine in Cleveland, told Medscape Medical News.

"Our data suggest that there was not a large clinically relevant difference between ranibizumab and sham groups, and that the magnitude of difference was similar at both 1 and 3 years," he reported.

Dr. Huang presented the findings here at the 31st Annual Meeting of the American Society of Retina Specialists.

DRCR.net Trial

In the Diabetic Retinopathy Clinical Research Network (DRCR.net) phase 3 study, eyes with diabetic macular edema were randomly assigned to prompt laser treatment (sham group) or to ranibizumab plus prompt or deferred laser treatment. There was no difference in adverse events related to IOP in any of the groups.

The investigators explored the DRCR.net data for evidence of IOP concerns, including sustained elevation of IOP.

The study population consisted of 582 eyes (486 patients) with diabetic macular edema and baseline vision of 20/32 to 20/320. A total of 322 eyes were treated with ranibizumab plus prompt or deferred laser therapy and 260 eyes were treated with prompt laser therapy.

The primary outcome of the study was the cumulative probability of developing a persistent elevation in IOP, defined as an IOP of 22 mm Hg or higher with a 6 mm Hg or more increase in IOP from baseline on 2 consecutive visits or initiation of IOP-lowering medications or procedures.

Mean baseline IOP was 16 mm Hg in both groups. Only 4% of sham-treated eyes and 5% of ranibizumab-treated eyes had an IOP of 22 to 24 mm Hg. At baseline, only 3% in either group had a history of glaucoma or was receiving an IOP-lowering medication.

At 1 year, approximately twice as many ranibizumab-treated eyes as sham-treated eyes met the primary outcome measure, but the difference between the 2 groups was not statistically significant. For eyes treated with ranibizumab, the hazard ratio for the primary outcome was 1.6.

Table. Outcomes at 1 Year

Outcome Sham Group, n (n = 260) Ranibizumab Group, n (n = 322)
Primary 10 20
   Persistent IOP elevation only 3 10
   IOP-lowering medication only 5 8
   IOP medication and persistent elevation 1 2
   Any glaucoma procedure 1 0

The proportion of eyes with any increase in IOP of 30 mm Hg or more at any visit was similar in the sham and ranibizumab groups (1% vs 2%), as was the proportion with an IOP increase of 10 mm Hg or more at any visit (5% vs 4%).

At 3 years, the primary outcome was achieved in 7% of sham-treated eyes and 14% of ranibizumab-treated eyes.

However, when patients with a history of glaucoma or who were receiving an IOP-lowering medication at baseline were excluded from the analysis, the cumulative probability of achieving the primary outcome at 3 years remained at 7% for sham-treated eyes but decreased to 12% for ranibizumab-treated eyes, Dr. Huang reported.

Session cochair George Williams, MD, who is chair of the Oakland University William Beaumont School of Medicine in Rochester, Michigan, told Medscape Medical News that elevated IOP has been a concern with all of the anti-VEGF agents.

"However, this study tells us that it is a relatively infrequent problem that does not seem to have a lot of clinical relevance," Dr. Williams explained. "We are still concerned about IOP, but it's not affecting our treatments and it's still a manageable problem if it does occur."

Dr. Huang and Dr. Williams report a number of financial disclosures, but none relevant to this particular study.

31st Annual Meeting of the American Society of Retina Specialists. Presented August 27, 2013.

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