Efficacy of APOQUEL® for the Control of Otitis Externa Secondary to Allergic Skin Disease in Client-Owned Dogs

Background: This single-arm, unmasked, single-site study was conducted to evaluate the efficacy of oclacitinib (APOQUEL®) administered twice daily for 14 days with a topical anti-infective, when indicated, for the control of otitis externa secondary to allergic skin disease in dogs. Thirteen (13) client-owned dogs were enrolled; three (3) dogs were withdrawn for owner non-compliance. Dogs were required to be ≥1 year old, weigh 3.0-80.0 kg, have uncomplicated otitis externa that the Investigator attributed to allergic skin disease, have an Otitis Index Score of ≥6 and been withdrawn from any systemic or topical treatments with antipruritic, anti-inflammatory or anti-infective properties that could interfere with assessments. Cytology samples were collected from each ear. Ears with otitis externa were cleaned at enrollment. Oclacitinib was administered orally twice daily; in dogs with evidence of infection, enrofloxacin/silver sulfadiazine (Baytril® Otic) was administered topically twice daily in affected ears. Owner assessments were performed daily and Investigator assessments were performed on Days 7 and 14. Results: Seven (7) female and three (3) male dogs completed the study. Ages ranged from 3.0-12.0 years and body weight ranged from 3.6-47.0 kg. Administration of oclacitinib and enrofloxacin/silver sulfadiazine twice daily for 14 days resulted in mean Investigator otitis scores improving from 19.7 on Day 0 to 3.4 by Day 14, for a mean reduction of 81.7%. Mean owner assessment improved by 94.7% (left ear) and 80.6% (right ear) during the 14-day study. Cytologic examination of the ears showed bacteria in seven left ears and seven right ears at enrollment compared to only one left ear and no right ears on Day 14. One dog had no bacteria or yeast on Day 0 compared to nine dogs with no bacteria on Day 14. Yeast was present in two left and two right ears at enrollment and in only one right ear on Day 14. Conclusions: The results of this single-arm, single-site, unmasked study suggest that oral administration of oclacitinib with a topical anti-infective applied to affected ears twice daily for 14 days is effective for the management of otitis externa secondary to allergic skin disease in dogs.