Across Albania (60), Germany (3), Spain (7), Portugal (14), and Poland (50), 134 dogs were enrolled, ranging in age in the oral fluralaner group from 10 weeks to 13 years (mean 3.1; standard deviation ± 2.9 years), in the spot-on fluralaner group from 4 months to 12 years (3.5 ± 3.2 years), and in the topical imidacloprid-moxidectin group from 11 weeks to 9 years (2.9 ± 2.9 years). A broad range of breed categories was represented, with approximately 50% of dogs mixed breed, 22% were companion-toy dogs, and approximately 9% were terriers.
During the study, of the 134 dogs that were enrolled, 10 became ineligible for inclusion in study efficacy assessments. Four dogs in the fluralaner spot-on group, two in the fluralaner chewable group and one dog in the imidacloprid-moxidectin group were excluded because of an owner failure to adhere to follow-up visit schedules. Two dogs were excluded because of treatment with study-prohibited drugs: one dog in the fluralaner chewable group received oclacitinib and dexamethasone, and a dog in the fluralaner spot-on group received dexamethasone. The death prior to day 56 of a fluralaner spot-on group dog that had shown weakness, anorexia, dyspnea and dehydration, was diagnosed as cardiac failure, unrelated to treatment. Thus, data from 124 dogs were available for determination of product efficacy, 50 in each of the fluralaner groups and 24 in the imidacloprid-moxidectin group. In the latter group most dogs received 4 treatments (once every 4 weeks), 5 dogs required 3 treatments; 2 dogs received 13 treatments (one per week); one received 10; and one received 7 treatments. Thus data were available from 124 dogs, 50 in the fluralaner chewable group (on day 0, 25 presenting with juvenile-onset and 25 with adult-onset demodicosis), 50 in the fluralaner spot-on group (20 juvenile-onset, 30 adult-onset demodicosis), and 24 in the topical imidacloprid-moxidectin group (12 with juvenile-onset, 12 with adult-onset demodicosis).
On days 56 and 84, in both fluralaner groups 98.0% of dogs had shown a parasitological cure (free of mites at two consecutive assessments) (Table 1). In the imidacloprid-moxidectin group, the percentage of mite-free dogs at both days 56 and 84 was 87.5%, below the pre-determined efficacy threshold of 90%. On day 84, 100% of fluralaner chewable and 98% of fluralaner spot-on treated dogs were free of live mites, as were 91.7% of dogs in the topical imidacloprid-moxidectin group.
Table 1. Number (percent) of dogs treated once, on day 0, with fluralaner chewables or fluralaner spot-on, or on multiple occasions with topical imidacloprid-moxidectin, that were negative for live mites at each assessment
Mean mite counts on day 0 in the fluralaner spot-on and chewable groups were 53.2 and 30.4, respectively, and 37.8 in the topical imidacloprid-moxidectin group (Table 2). For the 25 dogs in the fluralaner oral group that presented with juvenile-onset demodicosis, all but one were free of mites on both days 56 and 84 (efficacy 96.0%) (Table 3). For the fluralaner spot-on and imidacloprid-moxidectin groups, the equivalent efficacy against juvenile-onset demodicosis was 100% (20 of 20 dogs free of mites on days 56 and 84) and 91.7% (11 of 12 dogs), respectively. For efficacy against adult-onset demodicosis, in the fluralaner oral group 25 of 25 dogs (100%) were free of mites on both days 56 and 84, as were 28 of 29 (96.7%) dogs treated with spot-on fluralaner, and 10 of 12 dogs (83.3%) in the imidacloprid-moxidectin group.
Table 2. Mite counts (mean ± standard deviation) in dogs with generalized demodicosis treated once, on day 0, with fluralaner chewables or fluralaner spot-on, or on multiple occasions with topical imidacloprid-moxidectin.
Table 3. Percentage (number cured/number affected on day 0) of dogs with a parasitological cure of juvenile- or adult-onset demodicosis (mite-free on days 56 and 84) following a single treatment with oral or topical fluralaner, or multiple treatments with topical imidacloprid-moxidectin.
At the first visit (day 0), all enrolled dogs had clinical signs of generalized demodicosis, most commonly alopecia which was present in all study dogs. By day 84, there was no observable alopecia in 94.0% of oral fluralaner-treated dogs, 84.0% of spot-on fluralaner-treated dogs, and 75.0% of topical imidacloprid-moxidectin treated dogs. Other initial clinical signs included crusts (61.3% of dogs), erythema (58.9%), scales (34.7%), papules (26.6%), pustules (13.7%), ulcerations (9.7%) and comedones (4.0%). All signs of erythema, comedones, papules, pustules and ulcerations resolved in dogs in all groups by day 84. Overall there was a marked reduction in skin lesions in all groups at day 28, with substantial hair regrowth by Day 56 (Fig 1). Continuing improvement was observed at each subsequent visit through the final visit on day 84.
Fig 1. Photographs on day 0 of dogs with demodicosis-related dermatological lesions, and day 56 showing hair regrowth following a single fluralaner treatment on day 0; left fluralaner spot=-n; right fluralaner chewable.
No treatment-related adverse events were observed in any dogs in any of the three study groups.