Radiation Retinopathy: Treat-and-Extend Promising

DENVER — Intravitreal injections of aflibercept (Eylea) given in a treat-and-extend regimen can stabilize visual acuity and improve macular anatomy in eyes injured by radiation retinopathy, researchers say.

The trial is one of only two to show that anti-vascular endothelial growth factor (VEGF) treat-and-extend regimen such as those devised for diabetic retinopathy can be effective in this condition, said Stephanie Trejo Corona, BA, BS, a researcher at Retina Consultants of Texas.

"Given the similar clinical manifestations of radiation retinopathy with diabetic retinopathy, well-established diabetic retinopathy anti-VEGF treatments seem to be useful for the treatment of radiation retinopathy," she said in a presentation here at the Association for Research in Vision and Ophthalmology (ARVO) 2022 Annual Meeting.

Radiation plaque, proton beam, and orbital radiation therapy can all cause radiation retinopathy, resulting in poor long-term visual acuity for which the US Food and Drug Administration has not yet approved a treatment.

"A lot of patients don't want to deal with monthly visits," Corona told Medscape Medical News. "And because the treat-and-extend regimen does mimic more of a relaxed approach for administering the drug to patients, they would be more willing to come in and still have preservation and vision, whereas if they didn't come in at all, they would see devastating vision losses."

To investigate the safety and efficacy of an aflibercept treat-and-extend protocol, Corona and colleagues recruited 39 adults with a history of ocular or orbital radiation for ocular or orbital cancer and clinically identifiable radiation retinopathy with evidence of fluid on spectral domain optical coherence tomography (SD-OCT).

They excluded anyone with metastatic or active primary cancer, prior anti-VEGF treatment within 60 days of screening, prior intravitreal or subconjunctival treatment with cortical steroids within 60 days of screening, macula ischemia greater than 5 disc areas, or evidence of ocular infection at screening.

At baseline, the patients’ mean age was 60.2 years and 52.9% were female. Their mean best-corrected visual acuity (BCVA) was 60.1 ETDRS letters (20/63 Snellen). Their mean central retinal thickness (CRT) was 475.5 µm.

The researchers randomly divided the 39 patients into two groups. They gave a loading dose of 3 aflibercept injections to 20 individuals and no loading dose to the other 19.

After that, they gave injections to patients of both groups on a treat-and-extend regimen. They administered injections every 4 weeks, but extended the time between injections by 2 weeks if intraretinal and subretinal fluid appeared resolved on SD-OCT and loss of visual acuity since the previous visit was less than 5 ETDRS letters.

Four patients were lost to follow-up in the loading-dose cohort, and 1 in the no-loading-dose cohort.

After 52 weeks, the mean best-corrected visual acuity improved by 1.75 ETDRS letters in the half of the patients who received the loading dose, and by 6.17 letters in the cohort that did not receive the loading dose.

The overall improvement of 4.09 letters was not statistically significant compared with baseline (P < .07), and the difference between the two groups was not statistically significant.

But there was a statistically significant improvement in overall central retinal thickness, from 475.5 µm to 317.9 µm (P < .001). Visual acuity of 20/200 or better was achieved by 97.1% of patients.

There was no significant increase from baseline in capillary nonperfusion, and the number of eyes with exudates, optic disc edema, and retinal and vitreous hemorrhage all decreased. None of the patients had neovascularization.

These results are comparable to other trials in which anti-VEGF drugs were administered on a fixed dose regimen, said Corona.

The trial confirms the approach that most clinicians are using in treating radiation retinopathy, said Brian VanderBeek, MD, MPH, MSCE, an assistant professor of ophthalmology at the Hospital of the University of Pennsylvania in Philadelphia.

"I have treated some radiation retinopathy very similarly to diabetic macular edema and/or retinal vein occlusion macular edema," he told Medscape Medical News.

He looked forward to seeing the published version of this study so he can see exactly how long patients were able to go between injections.

Corona and VanderBeek have disclosed no relevant financial relationships.

Association for Research in Vision and Ophthalmology (ARVO) 2022 Annual Meeting. Presented May 1, 2022.

Laird Harrison writes about science, health and culture. His work has appeared in national magazines, in newspapers, on public radio and on websites. He is at work on a novel about alternate realities in physics. Harrison teaches writing at the Writers Grotto. Visit him at www. lairdharrison.com or follow him on  Twitter: @LairdH

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