16 and 24 Gy Low-voltage X-ray Irradiation With Ranibizumab Therapy for Neovascular Age-Related Macular Degeneration: 12-Month Outcomes

Abstract

To describe the 12-month safety and efficacy outcomes of 16 or 24Gy radiation using low-voltage x-ray irradiation in conjunction with intravitreal ranibizumab for neovascular age-related macular degeneration (AMD). Prospective, phase I, open-label, nonrandomized uncontrolled safety study. setting: Institutional. study population: Neovascular AMD patients. intervention: One x-ray irradiation treatment at 16 or 24Gy was administered externally through 3 locations in the inferior pars plana. After 2 initial monthly loading doses of ranibizumab, subsequent ranibizumab was administered according to predetermined criteria. main outcome measures: Visual acuity, number of ranibizumab injections, safety and efficacy metrics at 12months. Forty-seven eyes of 47 patients were enrolled and completed 12months of follow-up: 16Gy (n= 28) and 24Gy (n= 19). There was no evidence of radiation retinopathy, optic neuropathy, or cataract. The mean visual acuity improved in both groups:+8.4 ± 11.9 letters and+7.8 ± 12 letters for 16 and 24 Gy, respectively. In both groups, 100% of subjects lost <15 letters, with 76% and 79% gaining ≥0 letters in the 16Gy and24Gy groups, respectively. Patients received a mean of 1.0 additional injection over 12months. Themean change in optical coherence tomography central subfield thickness from baseline to month 12 was-107 and-87μm for the 16Gy and 24Gy groups, respectively. One treatment of 16 or 24Gy low-voltage x-ray therapy with as-needed ranibizumab appears safe in subjects with neovascular AMD at 12months. An overall improvement in visual acuity was observed. No radiation-related adverse effects were reported.