Efficacy of a single oral administration of a formulation of fluralaner, moxidectin and pyrantel (BRAVECTO® TriUNO) in dogs for the treatment and prevention of angiostrongylosis

Abstract Background Four studies investigated the efficacy of fluralaner/moxidectin/pyrantel chewable tablets (Bravecto® TriUNO) in preventing and treating canine angiostrongylosis; one study also included a formulation of fluralaner/milbemycin oxime. Methods Studies included eight or 10 dogs/group. In Studies 1 and 2 (prevention), dogs inoculated with third-stage larvae of Angiostrongylus vasorum on day − 31 or − 28 were randomized to groups by sex and body weight; in Studies 3 and 4 (treatment) by faecal first-stage larvae counts at approximately 8 weeks post-inoculation (PI). All studies included an untreated control group (CG). Study 1 included three groups treated with formulations of moxidectin/fluralaner/pyrantel; minimum moxidectin doses 0.0125, 0.025 or 0.055 mg/kg. The formulation with moxidectin at 0.025 mg/kg, 99.0% effective in preventing establishment of infection, was adopted as the investigational veterinary product (IVP) for the following studies. Study 2 included a group treated with either the IVP or a combination of fluralaner (10 mg/kg) with milbemycin oxime (0.75 mg/kg) (IVP-2). In all studies, the IVP was administered once on day 0; in Study 2, IVP-2 was administered on days 0, 31, 62 and 93. In Study 1, efficacy was determined by reductions in geometric mean necropsy worm counts approximately 33 days post-treatment versus mean CG counts, in the other studies by reductions in mean faecal L1 counts. Study 2 assessed pulmonary changes via thoracic computed tomography. Respiratory signs and serological antibody responses were monitored. Results In Study 1, all moxidectin doses exceeded 90% efficacy. In Study 2, IVP efficacy (one treatment) at 62 days was 100.0%; IVP-2 (four treatments) efficacy was 99.8% at 124 days. Respiratory signs were absent or lower in IVP-treated than CG dogs. In Studies 3 and 4, IVP efficacy was 100% by 3 and 4 weeks post-treatment, respectively. In all studies, lungworm count reductions in the IVP groups were statistically significant ( P < 0.0001) versus the CG. Serology confirmed A. vasorum infections in all control and IVP-2-treated dogs, and absence of infections in IVP-treated dogs. Treatments were well tolerated. Conclusions A single treatment with Bravecto TriUNO is highly effective in preventing angiostrongylosis and eliminating established A. vasorum infections. Infection-related lung pathology was reduced in treated dogs.