Subconjunctival Sirolimus in the Treatment of Autoimmune Non-necrotizing Anterior Scleritis: Results of a Phase I/II Clinical Trial

Abstract

To investigate the safety, tolerability and efficacy of subconjunctival sirolimus injections as a treatment for active, autoimmune, non-necrotizing anterior scleritis. Phase I/II, single-center, open-label, nonrandomized, prospective pilot study. Five participants with active, autoimmune, non-necrotizing anterior scleritis with scleral inflammatory grade of ≥1+ in at least 1 quadrant with a history of flares were enrolled. A baseline injection was given, with the primary outcome measure of at least a 2-step reduction or reduction to grade zero in the study eye by 8 weeks. Secondary outcomes included changes in visual acuity and intraocular pressure, ability to taper concomitant immunosuppressive regimen, and number of participants who experienced a disease flare requiring reinjection. Safety outcomes included the number and severity of systemic and ocular toxicities, and vision loss ≥15 ETDRS letters. The study included 6 visits over 4 months with an extension phase to 1 year for participants who met the primary outcome. All participants (N = 5, 100%; 95% CI [0.60, 1.00]) met the primary outcome in the study eye by the week 8 visit. There was no significant change in mean visual acuity or intraocular pressure. Three out of 5 patients (60%) experienced flares requiring reinjection. No systemic toxicities were observed. Two participants (40%) experienced a localized sterile inflammatory reaction at the site of the injection, which resolved without complication. Subconjunctival sirolimus leads to a short-term reduction in scleral inflammation, though relapses requiring reinjection do occur. There were no serious adverse events, though a local sterile conjunctival inflammatory reaction was observed.