Low-dose oral administration of interferon-alpha for the treatment of immune-mediated keratoconjunctivitis sicca in dogs.
This preliminary study was designed to evaluate the effectiveness and dosage of oral use of interferon-alpha (IFN-alpha) in the treatment of naturally occurring, immune-mediated, canine keratoconjunctivitis sicca (KCS). Dogs with chronic immune-mediated KCS were selected from the two clinic populations. All medication, except topical artificial tears, was discontinued at least 2 weeks prior to beginning the clinical trial. IFN-alpha was administered orally once daily to the dogs by their owners as the sole therapy for the KCS. Examinations of the dogs were performed every 2 weeks for the duration of the trial (12 weeks). Each dog was given either two or three separate, escalating doses (20, 40, 80 IU of the IFN-alpha. A favorable response was observed in 55% (11/20) of all dogs treated. Clinical findings of those dogs that responded included increased wetting of the eyes, decreased mucus discharge, and fewer signs of discomfort. There was a nearly significant difference (p = 0.08) in pretreatment mean Schirmer's tear test (STT) between the dogs that responded (6.4 +/- SEM 0.62 mm/min) and those that did not respond (4.7 +/- SEM 0.69 mm/min) to the orally administered IFN-alpha. Seven of 11 dogs with favorable outcomes had an increased STT of at least 5 mm/min after treatment with oral IFN-alpha and the group had a post-treatment STT (10.5 +/- SEM 1.4 mm/min) significantly greater than baseline (p = 0.0004). The post-treatment STT of the dogs that did respond was significantly greater (p < 0.01) than the post-treatment mean STT of dogs that did not respond. All dogs that responded did so with the 20 or 40 IU dose of IFN-alpha. No side effects were noted and all dogs tolerated the treatment well.
Gilger
B C
BC
Department of Companion Animal and Special Species Medicine, College of Veterinary Medicine, North Carolina State University, Raleigh 27606, USA.
Rose
P D
PD
Davidson
M G
MG
Roberts
S M
SM
Miller
T
T
D000284:Administration, Oral; D000818:Animals; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D005260:Female; D016898:Interferon-alpha / Q000009:adverse effects / Q000627:therapeutic use*; D007638:Keratoconjunctivitis Sicca / Q000188:drug therapy / Q000276:immunology / Q000662:veterinary*; D008297:Male; D016896:Treatment Outcome
D016898:Interferon-alpha