The conclusion of a comparative efficacy study of fluralaner and sarolaner against the tick Amblyomma americanum on dogs is based on results obtained at study times that are outside the fluralaner…

Rob Armstrong

The only fluralaner-related conclusion presented in a study comparing the efficacy of fluralaner and sarolaner for control of the tick Amblyomma americanum on dogs is based on study times that are outside the label administration recommendations. Label recommendations for fluralaner treatment of A. americanum on dogs in the USA require re-administration at 56 days. This 56 day re-administration was not conducted in the study; therefore, all assessed time points following 56 days post-treatment in the study present comparisons that are not consistent with fluralaner administration recommendations. The only comparative time point assessed prior to 56 days showing a difference between treatments was at 42 days post-administration, a time point when methodological problems were identified by the investigators. Therefore, the only comparative study conclusion that a difference was shown between fluralaner and sarolaner beyond 6 weeks (42 days) after treatment is not based on recommended product use. Furthermore, if the study does not show that there is a difference between the treatments at times when the products are used as recommended, then there also can be no comparative discussion of the risk of tick-borne pathogen transmission risk between treatments.