Epimacular brachytherapy for neovascular age-related macular degeneration: a randomized, controlled trial (CABERNET)

Abstract

Purpose: To evaluate the safety and efficacy of epimacular brachytherapy (EMBT) for the treatment of neovascular age-related macular degeneration (AMD).

Design: Multicenter, randomized, active-controlled, phase III clinical trial.

Participants: Four hundred ninety-four participants with treatment-naïve neovascular AMD.

Methods: Participants with classic, minimally classic, and occult lesions were randomized in a 2:1 ratio to EMBT or a ranibizumab monotherapy control arm. The EMBT arm received 2 mandated, monthly loading injections of 0.5 mg ranibizumab. The control arm received 3 mandated, monthly loading injections of ranibizumab then quarterly injections. Both arms also received monthly as needed (pro re nata) retreatment.

Main outcome measures: The proportion of participants losing fewer than 15 Early Treatment Diabetic Retinopathy Study (ETDRS) letters from baseline visual acuity (VA) and the proportion gaining more than 15 ETDRS letters from baseline VA.

Results: At 24 months, 77% of the EMBT group and 90% of the control group lost fewer than 15 letters. This difference did not meet the prespecified 10% noninferiority margin. This end point was noninferior using a 20% margin and a 95% confidence interval for the group as a whole and for classic and minimally classic lesions, but not for occult lesions. The EMBT did not meet the superiority end point for the proportion of participants gaining more than 15 letters (16% for the EMBT group vs. 26% for the control group): this difference was statistically significant (favoring controls) for occult lesions, but not for predominantly classic and minimally classic lesions. Mean VA change was -2.5 letters in the EMBT arm and +4.4 letters in the control arm. Participants in the EMBT arm received a mean of 6.2 ranibizumab injections versus 10.4 in the control arm. At least 1 serious adverse event occurred in 54% of the EMBT arm, most commonly postvitrectomy cataract, versus 18% in the control arm. Mild, nonproliferative radiation retinopathy occurred in 3% of the EMBT participants, but no case was vision threatening.

Conclusions: The 2-year efficacy data do not support the routine use of EMBT for treatment-naïve wet AMD, despite an acceptable safety profile. Further safety review is required.