Study designs

The four studies were designed in accordance with the “World Association for the Advancement of Veterinary Parasitology (WAAVP) guidelines for evaluating the efficacy of parasiticides for the treatment, prevention and control of flea and tick infestation on dogs and cats” [20]. Specific local guidelines were also applied, for the European Union (EU): “Guideline for the Testing and Evaluation of the Efficacy of Antiparasitic Substances for the Treatment and Prevention of Tick and Flea Infestation in Dogs and Cats”, EMEA/CVMP/EWP/005/2000-Rev.3; for Australia: “Preamble for the WAAVP guideline for fleas and ticks on dogs and cats version 1 (1 July 2014)”.

The four studies were conducted in accordance with Good Clinical Practices as described in “International Cooperation on Harmonization of Technical Requirements for Registration of Veterinary Medicinal Products (VICH) guideline GL9”.

The studies were carried out on domestic cats under the responsibility of a veterinarian, in different regions of the world, i.e. 11 sites in the United States: Florida (3), Louisiana (2), Missouri (2), Oregon (1), Tennessee (1), Georgia (1), and Mississippi (1); 16 sites in Europe: France (9), Portugal (1), Germany (3), Hungary (1), Bulgaria (1), Romania (1); 11 sites in Japan in Kanto, Chubu and Kyushu: Tokyo (2), Gunma (3), Nagano (1), Fukuoka (1), Kumamoto (3) and Okinawa (1); and 2 regions in Australia: Queensland (2), and New South Wales (2).

The primary objective of the four studies was to evaluate efficacy of the novel formulation against fleas one month after an application. Nevertheless, the four studies had different contexts, secondary objectives and designs, as summarized in Table 1.

Study designs.

For inclusion, the cats were naturally infested with at least five fleas (at least six fleas in Australia). Neither the cat nor the environment had been treated with any ectoparasiticide compound within four weeks of inclusion. Cats were randomly allocated to the novel formulation or the positive control group based on order of presentation at the site in a 2:1 ratio (US and EU) or 1:1 ratio (Japan), except in Australia where no control group was used. In the USA, EU and Australia, one cat with appropriate flea infestation, the sentinel cat, was selected per household for efficacy and tolerance evaluation. When applicable, the other cat(s) of the same household were treated with the same drug as the sentinel cat and only evaluated for tolerance. In the EU (all cats) and the USA (sentinel cats), study cats affected by flea infestation-related cutaneous disorders were evaluated for reductions of these signs. In Japan, in multi-cat households, each cat was independently allocated, treated and evaluated for efficacy and tolerance.

Most study activities (flea infestation evaluations, treatments, and physical examinations) were performed at the veterinary practices, except day-to-day owner observations. The study activity schedules are summarized in Table 2.

Study schedules.

RC = flea removal and count; T = Treatment; isC = in situ flea thumb count (without flea removal).

Physical examinations for tolerance evaluations were performed at all visits (except in Australia).

The flea efficacy assessment was based on comparison of the number of live fleas found before treatment to the number of live fleas found after treatment, at the scheduled visits.

In Australia, blinding was not applicable as no control group was used; otherwise, all personnel collecting efficacy, tolerance or flea-infestation cutaneous signs data were blinded to treatment. Owners were blinded to treatment in the EU and Japan. In the USA, the owners were not blinded as they administered the treatments.

Any drug that could influence the safety and/or efficacy assessments was not allowed. Any concurrent medication that could positively influence the resolution of cutaneous signs (e.g. corticosteroids, immunomodulators, dermatological topical substances, or medicated shampoos) were allowed for animal welfare purposes. Nevertheless such use excluded the animal from evaluation of reduction of flea infestation-related cutaneous signs.