Abstract
Purpose: :
To compare the efficacy of an aqueous calcineurin inhibitor, SCY-641, and 1% cyclosporine in the treatment of spontaneous, naturally occurring immune-mediated keratoconjunctivitis sicca (KCS) in dogs.
Methods: :
A randomized, blinded, placebo-controlled, clinical study of 56 days duration was performed in dogs with immune-mediated KCS assigned to treatment with topical twice-daily aqueous calcineurin-inhibitor solution (SCY-641), 1% cyclosporine in oil (CsA), or artificial tears (AT) by the study administrator. Dogs entered into the study were either previously untreated or had a washout period of at least 7 days. Clinical examination and schirmer tear tests (STT) were performed prior to therapy and at Days 7, 14, 28, and 56 after initiation of treatment.
Results: :
Thirty dogs were enrolled in the study. No adverse effects were noted with any treatment and all treatments appeared to be well-tolerated. There were no significant differences in STT values in dogs of the 3 groups prior to therapy (Day 0; mean STT 8.7 +/- 2.3 mm/min) or after 7 days of treatment. However, at day 14, STT values in dogs treated with CsA (mean STTv24.1 +/- 5.3 mm/min), was significantly higher than the STT in dogs treated with SCY-641 (mean STT 17.4 +/- 5.0 mm/min) (Student’s t test; P=0.001), which in turn was significantly higher than STT in dogs treated with AT (mean STT 11.0 +/- 7.5 mm/min) (Student’s t test; P=0.003). By day 28 and at day 56, there were no significant differences between STT of dogs treated with CsA (mean STT 23.8 +/- 3.8 mm/min; 23.0 mm/min) or SCY-641 (mean STT 18.2 +/- 5.4 mm/min; 17.7 +/-7.1 mm/min), while both groups had STT higher than the AT treated group.
Conclusions: :
SCY-641 was well tolerated by dogs with naturally occurring KCS. By 14 days, dogs treated with SCY-641 had significantly higher STT than placebo treated dogs and by 28 days STT values in dogs treated with SCY-641 were not significantly different than dogs treated with standard-of-care topical CsA. These results indicate that topical SCY-641 is as efficacious in a spontaneous model of KCS as topical CsA. Further evaluation of SCY-641 is warranted for treatment of canine and human immune-mediated KCS.
Keywords: cyclosporine • cornea: tears/tear film/dry eye • autoimmune disease