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Testing drugs for diabetic macular edema

Diabetic macular edema can be detected with a comprehensive dilated eye exam.Attila Barabas/iStock/Thinkstock

Diabetic macular edema is a consequence of diabetes that can cause blurring of central vision due to the leakage of fluid from abnormal blood vessels in the retina. Eylea (aflibercept), Avastin (bevacizumab), and Lucentis (ranibizumab) are all widely used to treat the disease. Injected into the eye, these drugs work by inhibiting vascular endothelial growth factor, a substance that can promote abnormal blood vessel growth and leakage. Despite their similar mode of action, the drugs’ costs differ significantly.

The Diabetic Retinopathy Clinical Research Network, funded by NIH’s National Eye Institute (NEI), conducted a 2-year clinical trial to compare the 3 drugs. Investigators enrolled 660 people with diabetic macular edema at 89 sites across the country. On average, participants were 61 years old with 17 years of type 1 or type 2 diabetes. About half the participants had 20/32 to 20/40 vision. The other half had 20/50 or worse vision.

Participants were assigned randomly to receive Eylea (2.0 milligrams/0.05 milliliter), Avastin (1.25 mg/0.05 mL), or Lucentis (0.3 mg/0.05 mL). Based on Medicare allowable charges, the per-injection costs of the drugs at these doses were about $1,850, $60, and $1,200, respectively. Participants were evaluated monthly during the first year and every 4-16 weeks during the second year. Most participants received monthly injections during the first 6 months. Thereafter, they received additional treatments as needed. Results of the study were published online on February 27, 2016, in Ophthalmology.

Among participants with 20/40 or better vision, all 3 drugs improved vision similarly. On average, participants’ vision improved from 20/40 to 20/25.

Among participants with 20/50 or worse vision at the trial’s start, visual acuity improved substantially in all 3 groups. At 2 years, gains were greater for those receiving Eylea than for those receiving Avastin. There was no statistically significant difference when comparing directly Eylea and Lucentis, contrary to year-one results from the study, which showed Eylea with a clear advantage.

The number of injections participants needed was about the same for the 3 treatments, as was the rate of eye complications, such as eye infections and inflammation. The need for laser treatment—the standard treatment until adoption of these drugs—varied. By 2 years, 41% of participants in the Eylea group had received laser treatment, compared with 64% in the Avastin group and 52% in the Lucentis group.

Cardiovascular events such as heart attack and stroke are common complications of diabetes. Twelve percent of Lucentis participants had at least 1 event, compared with 5% in the Eylea group and 8% in the Avastin group. This difference hasn’t been seen in other studies and needs further examination.

“This rigorous trial confirms that Eylea, Avastin, and Lucentis are all effective treatments for diabetic macular edema,” says NEI Director Dr. Paul A. Sieving. These results will help doctors and patients with diabetic macular edema choose the most appropriate therapy.