16 Gy low-voltage x-ray irradiation followed by as needed ranibizumab therapy for age-related macular degeneration: 12 month outcomes of a 'radiation-first' strategy.

Background and Objective: To describe 'radiation-first' combination treatment with a non-invasive, low-voltage x-ray irradiation system followed by as needed ranibizumab for neovascular age-related macular degeneration (AMD).
Study Design and Methods: Phase I study of non-invasive, low-voltage 16 Gy x-ray irradiation delivered in three beams via the inferior pars plana in patients with active neovascular AMD. Ranibizumab was administered as needed per protocol. Patients were followed monthly for safety and efficacy over 12 months.
Results: 13 patients were enrolled and completed 12 months follow-up. Safety was good with no serious ocular/non-ocular adverse events or radiation-related ocular complications. 11 patients lost <15 Early Treatment of Diabetic Retinopathy Study (ETDRS) letters, seven gained ≥0 ETDRS letters and 0 gained ≥15 ETDRS letters. Patients received a total of 31 subsequent ranibizumab injections (of possible 156) over the 12 months following x-ray irradiation. Mean time to first injection was 3.9 months. One patient received no ranibizumab injections, three patients received one injection, four patients received two injections, and five patients received three or more injections.
Conclusions: After 12 months, non-invasive, low-voltage x-ray irradiation with as needed ranibizumab rescue therapy demonstrated good safety with a visual acuity stabilising effect and reduction in retinal thickness in patients with neovascular AMD.