A preclinical study of the intraocular pressure lowering efficacy of bimatoprost sustained release in eyes pretreated with selective laser trabeculoplasty

Purpose Selective Laser Trabeculoplasty (SLT) is a treatment for lowering intraocular pressure (IOP) in patients with glaucoma, however IOP‐lowering is not sustained after SLT over long term in a substantial proportion of patients. Recent human studies found less reduction in IOP when SLT and topical prostaglandin analogues (PGA) were used in combination. Bimatoprost Sustained Release (BimSR) implant is currently in development as an IOP‐lowering agent delivered intracamerally (IC). The purpose of this study was to assess the efficacy of BimSR in both eyes of a cohort of dogs following unilateral SLT treatment. Methods Unilateral SLT was performed in 11 female, normotensive, drug‐naïve beagle dogs. IOP was monitored up to 10 weeks following SLT. Six to ten weeks post SLT, nine of 11 eyes returned to their baseline IOP. Dogs were administered BimSR (15 μ g) IC in both eyes. Percent change in IOP from baseline was calculated in SLT‐treated and naïve eyes. Data expressed as mean ± SE. A linear mixed effects model was used to evaluate the treatment effect of BimSR in SLT‐treated and contralateral SLT‐naïve eyes. Results BimSR was equally efficacious in lowering IOP in both SLT‐treated and SLT‐naïve eyes. Mean percent decrease in IOP following BimSR administration to SLT‐treated eyes was 34.2% ± 2.8 and 34.7% ± 1.7 in contralateral, SLT‐naïve eyes. BimSR lowered IOP equally in eyes that responded to SLT (sustained decrease in IOP of ≥3 mmHg in the laser treated eye, n = 6, mean percent IOP decrease, 34.3% ± 4.2) and eyes that did not respond to SLT treatment (decrease in IOP of <3 mmHg in the laser treated eye, n = 5, mean percent IOP decrease, 34.1% ± 2.7). Conclusions Intracameral BimSR had substantial IOP‐lowering effects in eyes previously treated with SLT, suggesting that eyes that have been treated with SLT can still benefit from IC drug delivery of the BimSR implant. Importantly, BimSR was effective in lowering IOP in eyes that were previously non‐responders to SLT.