A phase 2 study1 of the ORION-1 (AR-1105, Aerie Pharmaceuticals) dexamethasone implant indicated that 2 formulations of the implants with different profiles for releasing the steroid successfully improved vision and decreased retinal thickening due to macular edema in patients with branch or central retinal vein occlusion, according to Michael Singer, MD, lead author of the study. He is from Medical Center Ophthalmology Associates, San Antonio, Texas.
The study patients underwent 1 intravitreal injection of 340 µg of dexamethasone. During the initial phase, 5 patients received the clinical formulation (CF) 1, and during the randomized phase, 44 patients randomly received either CF1 or CF2. The patients were evaluated at 6 months.
The study patients lost vision because of macular edema in CRVO that was diagnosed 9 or more months before screening or BRVO diagnosed 12 months before screening. The patients were included if they were treatment-naive or had received steroids and had a response.
The investigators reported that “both formulations improved vision and reduced retinal thickening from baseline across all visits. At month 6, the mean changes in the best-corrected visual acuity were +4.3 and +8.0 letters, and the mean changes in central subfield thickness were −93 µm and −211 µm, respectively, with CF1 and CF2.”
Decreased visual acuity, worsening of macular edema, conjunctival hemorrhages, and increased intraocular pressure (IOP) were the most common adverse events. No patients required surgery or laser for the increased IOP.
Based on the results, the authors concluded that both formulations of AR-1105 were well-tolerated and provided clinically meaningful and sustained visual improvements in vision and decreased retinal thickening despite that some patients had difficult-to-treat BRVO or CRVO with longstanding edema.
However, the CF2 formulation had a further advantage in that it provided a sustained treatment effect for 6 months, indicating the potential for longer treatment intervals and reduced treatment burden compared with the currently used intravitreal corticosteroids. The CF2 formulation will undergo further evaluation in a phase 3 study of retinal disease, the investigators reported.
1. Singer MA, Boyer DS, Williams S, et al. Phase 2 randomized study (orion-1) of a novel, biodegradable dexamethasone implant (AR-1105) for the treatment of macular edema due to central or branch retinal vein occlusion. Retina. 2023;43:25-33; doi: 10.1097/IAE.0000000000003632