Efficacy of a novel chewable tablet containing sarolaner, moxidectin and pyrantel (Simparica Trio) against four common tick species infesting dogs in Europe.

BACKGROUND: Tick infestations can cause direct deleterious effects to dogs as a result of tick blood-feeding, and indirectly ticks can transmit disease agents that can be detrimental to the health of both dogs and humans. Six laboratory studies were conducted to support dosage selection and efficacy confirmation of a novel combination of sarolaner, moxidectin and pyrantel against four tick species that commonly infest dogs in Europe. METHODS: Two studies were conducted against Dermacentor reticulatus (one of which was a dose determination study), two against Ixodes ricinus, and one each against Ixodes hexagonus and Rhipicephalus sanguineus (sensu lato). In each study, eight purpose-bred Beagle or mix-breed dogs were randomly allocated to each treatment group and infested with 50 unfed adult ticks on Days-2, 5, 12, 19, 26 and 33. On Day 0 dogs were treated orally with placebo or the combination product. In the dose determination study, dogs received sarolaner at point dosages of 0.6 mg/kg, 1.2 mg/kg or 2.4 mg/kg in combination with moxidectin and pyrantel, and in all other studies dogs received Simparica Trio to provide minimum dosages of 1.2 mg/kg sarolaner, 24 microg/kg moxidectin and 5 mg/kg pyrantel (as pamoate salt). Efficacy was assessed based on live tick counts conducted 48 hours after treatment and each weekly infestation. RESULTS: There were no treatment-related adverse events in any study. In the dose determination study, 1.2 mg/kg sarolaner was the lowest dosage evaluated that provided > 90% efficacy for at least 28 days and therefore was selected as the dosage to provide tick control for at least one month following a single oral treatment. In the dose confirmation studies, a single oral dose of Simparica Trio provided >/= 99.2% efficacy against existing infestations of all tick species, and against re-infestations efficacy was >/= 97.2% against D. reticulatus for 28 days and against all other species for 35 days. CONCLUSIONS: These studies support the sarolaner dose selected and confirm the efficacy of a single oral dose of Simparica Trio against existing infestations and re-infestations of the common tick species infesting dogs in Europe for at least one month.