Subconjunctival liposomal sirolimus vs. cyclosporine or tacrolimus as treatment of keratoconjunctivitis sicca in dogs: A double-blind, randomized study.

Purpose: To compare the safety and efficacy of a 100 microgram subconjunctival injection of liposome-encapsulated sirolimus (SCJS) to cyclosporine (CsA) or tacrolimus (CsA/T) for the treatment of keratoconjunctivitis sicca (KCS) in dogs.

Methods: Dogs with signs and symptoms of KCS were block-randomized to one of two treatment groups: Biweekly SCJS or conventional treatment (CsA/T). Schirmer tear test 1 (STT-1) scores, conjunctival hyperemia (CH) scores, corneal opacity (CO) scores, and clinical evaluation of potential side effects were recorded every 2 weeks for 14 weeks for both groups. Differences between groups were analyzed using the mixed results ANOVA and U-Mann Whitney tests (p < .05 was considered significant).

Results: A total of 30 eyes were included in the study, of which 20 eyes completed follow-up. There was no statistically significant interaction between the treatment group and time on STT-1 score (p = .165), and median CH and CO scores showed no statistically significant differences between groups (p = .353 and p = .393, respectively). There were no clinically significant side effects present in any subject at any time.

Conclusion: In this trial, a 1 mg/mL (100 micrograms) SCJS every 2 weeks showed similar safety and efficacy profiles as daily CsA/T in dogs with KS after 14 weeks of treatment. Larger studies should be performed to further assess SCJS as an alternative treatment for KCS.