Epimacular Brachytherapy Ineffective Against Neovascular ARMD

While anti-vascular endothelial growth factor (VEGF) treatment produces better outcomes than the natural history of neovascular age-related macular degeneration (ARMD), a less burdensome and expensive and more durable treatment would improve care.

A team, led by Timothy L. Jackson, PhD, FRCOphth, Faculty of Life Sciences and Medicine, King's College London, assessed the efficacy and safety of epimacular brachytherapy (EMB) for chronic, active, neovascular ARMD.

The investigators conducted the Macular Epiretinal Brachytherapy vs Ranibizumab (Lucentis) Only Treatment (MERLOT) pivotal device trial at 24 National Health Service hospitals in the UK involving 363 patients, 329 of which completed the entire follow-up period.

Eligible patients had neovascular ARMD and received intravitreal ranibizumab and were randomized 2:1 and stratified by lens status and angiographic lesion type to receive either EMB with as-needed ranibizumab or as-needed ranibizumab monotherapy.

The investigators also followed up with each patient monthly for 24 months and then assessed at a final visit at month 36.

The team sought co-primary outcomes of the number of as-needed ranibizumab injections and the mean change in Early Treatment Diabetic Retinopathy Study (ETDRS) BCVA with a noninferiority margin of -5 ETDRS letters.

They also sought secondary outcomes of the percentage of participants losing fewer than 15 ETDRS letters and gaining 0 or more or 15 or more ETDRS letters and the mean change in angiographic total lesion size, choroidal neovascularization size, and foveal thickness on optical coherence tomography.

The mean age of the combined group was 76.5 years old and the mean number of ranibizumab injections was 9.3 in the EMB group and 8.3 in the ranibizumab group, with a difference of 1.0 injections (95% CI, —0.3 to 2.3; P = .13).

The mean BCVA change was -11.2 ETDRS letters in the EMB group and -1.4 ETDRS letters in the ranibizumab arm, with a difference of 9.8 ETDRS letters (95% CI, —6.7 to –12.9).

For the EMB treatment group, 65.6% of participants (n = 160) lost fewer than 15 ETDRS letters, while 86.6% (n = 103) in the ranibizumab group lost fewer than 15 ETDRS letters, with a difference of 21% (95% CI, 12.4%-29.5%; P&thinsp;<&thinsp;.001).

Microvascular abnormalities occurred in 20 of 207 eyes in the EMB group, but only 1 of 97 eyes in the ranibizumab group. These abnormalities occurred outside the foveal center, with no unexpected safety concerns.

“The MERLOT trial found that despite the acceptable safety of EMB, it did not reduce the number of ranibizumab injections and was associated with worse visual acuity than anti-VEGF treatment alone; these results do not support EMB use as an adjunct treatment for chronic, active neovascular ARMD,” the authors wrote.

ARMD is currently the leading cause of blindness in European and North American countries. Anti-vascular endothelial growth factor agents have become a standard treatment for neuovascular ARMD.

The study, “Evaluation of Month-24 Efficacy and Safety of Epimacular Brachytherapy for Previously Treated Neovascular Age-Related Macular Degeneration,” was published online in JAMA Ophthalmology.