Arévalo, J. Fernando

Background/Objectives: Exudative age-related macular degeneration (AMD) is a disease of choroidal neovascularization that causes blindness. Current treatments to preserve vision in this prevalent and blinding condition are repeat intraocular injections of anti-vascular endothelial growth factor medicines for a patient’s lifetime to preserve and prevent vision loss leading to blindness. Rifampicin, a small-molecule antibiotic, has previously been reported to exhibit anti-angiogenic properties and a topical safety profile that is well-tolerated. Based on this evidence, we investigated the feasibility of formulating rifamycin as an ophthalmic drop capable of delivering therapeutic concentrations to the posterior segment of the eye. Methods: Inhibition of neovascularization by administration of rifampicin was analyzed in the rat oxygen-induced retinopathy (OIR) and mouse laser-induced choroidal neovascularization (CNV) models. Pharmacokinetic (PK) studies were conducted in mice, rats, and rabbits by dosing various formulations containing rifampicin, and the compound was quantified by LC/MS analysis. Results: Results from dose escalation studies in the mouse laser-induced CNV model suggested the minimum effective dose of rifampicin required for inhibiting neovascularization in subretinal tissues to be 0.7 mg/kg, which is substantially lower than the 20 mg/kg dosage approved for infectious disease treatments. The previous studies did not report the minimum effective dose in the anti-angiogenesis effects. The effective area under the concentration-time curve (AUC) in the sub-retina was evaluated as 0.27 h·ng/mg. In rabbits, rifampicin was delivered to the sub-retina by a single topical application of various formulations in a dose-dependent manner. The topical application of the formulations containing 1% rifampicin, which was well-tolerated in clinical trials previously reported for ocular trachoma, achieved subretinal delivery approximately 2–32 times greater than the effective AUC. Plasma exposure of the compound by the topical application was evaluated to range approximately 0.5–10 ng/mL. Conclusions: Rifampicin was delivered to the sub-retina in rabbits with an efficiency greater than the effective dose required for inhibiting neovascularization. Limited amounts of plasma exposure by the topical application were detected. These results suggested the therapeutic potential of the rifampicin formulations for the topical treatment of exudative macular degeneration.

Purpose: To report the anatomic and visual outcomes of eyes developing delayed rhegmatogenous retinal detachment (RRD) after macular surgery. Methods: This was a retrospective, multicentric study including eyes undergoing RRD repair at least 3 months after macular surgery for either full-thickness macular hole (FTMH) or epiretinal membrane (ERM). Anatomic and functional assessment, i.e., pre- and postoperative best-corrected visual acuity (BCVA), indications and details of macular and RRD surgery, time interval from macular surgery to RRD, intraocular tamponade, location, extent of RRD, and nature of retinal break, was performed. Results: Sixteen out of 2,906 eyes (0.55%) undergoing macular surgery developed RRD after 8.4 ± 5.8 months (mean ± SD). Intraoperative peripheral retina evaluation showed missed/de novo break (11 eyes; 68.75%), no identifiable break i.e., probable microbreak (two eyes; 12.5%), giant retinal tear (two eyes; 12.5%), and retinoschisis related break (one eye; 6.25%). Anatomical success, i.e., attached retina after one surgery, was seen in 14 eyes (87.5%). BCVA worsened from 0.6 ± 0.3 logMAR (Snellen equivalent 20/80) at baseline to 0.9 ± 0.8 logMAR (20/160) through the last visit (P < 0.001). Conclusion: RRD after macular surgery occurs predominantly via missed/de novo retinal breaks. A significant percentage (50%) of eyes showed worse visual acuity compared with baseline despite successful retinal reattachment.

We treated 26 eyes of 25 young patients having a mean age of 30 years with intravitreal vascular endothelial growth factor (VEGF) inhibitor for choroidal new vessel (CNV) formation overlying choroidal osteoma over a mean follow-up of 26 months. Mean number of injections was 2.4 at 6 months, 3.2 at 12 months, and 5.5 at 24 months. CNV was subfoveal in 14 eyes, juxtafoveal in 5, extrafoveal in 5, and peripapillary in 2. By paired comparison, mean decrease from baseline was 119.7 microns at 6 months (n=15;P=0.001), 105.3 microns at 1 year (n=10;P=0.03), and 157.6 microns at 2 years (n=7;P=0.08). BCVA improved by 3.3 lines at 6 months after therapy (n=26;P<0.001), 2.8 lines (n=20;P=0.01) at 1 year, and 3.1 lines (n=13;P=0.049) at 2 years. We conclude that intravitreal anti-VEGF injections improve vision in majority of eyes with CNV from choroidal osteoma.