Effectiveness of a novel orally administered combination drug product containing milbemycin oxime and lotilaner (Credelio® Plus) for the treatment of larval and immature adult stages of Ancylostoma caninum in experimentally infected dogs.

BACKGROUND: The hookworm, Ancylostoma caninum, is a common and important zoonotic intestinal nematode parasite that infects dogs globally. Both the immature and adult stages of A. caninum ingest large volumes of blood during the feeding process and can cause severe anemia and death in young dogs, even before patent infections can be diagnosed using routine faecal examination methods. Thus, effective treatment of any pre-patent stages of immature hookworms can reduce or eliminate the risk of clinical disease in infected dogs and additionally reduce environmental contamination of eggs and infective larvae. Two randomized, blinded, GCP-compliant, pivotal laboratory dose confirmation studies were conducted to evaluate the effectiveness and safety of a new novel combination of lotilaner and milbemycin oxime tablets (Credelio Plus®) administered orally to dogs experimentally infected with immature (L4 and immature adult [L5]) stages of A. caninum. METHODS: Treatments using the intended global commercial tablet formulation of Credelio Plus were administered in a time frame relative to inoculation with infective larvae so that effectiveness could be assessed against each specific immature stage of A. caninum. In each study, dogs were randomized to one of six (study 1) or four (study 2) treatment groups. Each treatment group contained 8 (study 1) or 10 (study 2) dogs that had been experimentally inoculated with infective A. caninum larvae on day 0 and were dosed once on day 7 or day 11. Enrolled subjects were administered placebo tablets, Credelio Plus tablets, or lotilaner mono tablets to provide minimum dosages of 0.75 mg/kg of milbemycin oxime and 20 mg/kg of lotilaner. All dogs were necropsied 5 days after their respective treatment. All nematodes recovered from the gastrointestinal tract at necropsy were counted by species and stage. RESULTS: For both dose confirmation studies and based on geometric mean worm counts, efficacy of Credelio Plus was ≥ 97.3% against L4 larval stage of A. caninum and ≥ 98.7% against immature adult (L5) A. caninum. CONCLUSIONS: These studies demonstrated that the orally administered Credelio Plus combination tablet was highly efficacious in treating immature (L4 and immature adult [L5]) stages of A. caninum in experimentally infected dogs.

Field study to investigate the effectiveness and safety of a novel orally administered combination drug product containing milbemycin oxime and lotilaner (Credelio® Plus) for the prevention of heartworm disease (Dirofilaria immitis) in client-owned dogs in the USA.

BACKGROUND: Dirofilaria immitis, a globally distributed filarial parasite of dogs, is known to cause serious or fatal cardiopulmonary disease. Client-owned dogs were enrolled in a clinical field study in the USA to evaluate the clinical effectiveness and field safety of an orally administered combination investigational product (IP) containing milbemycin oxime and lotilaner (Credelio® Plus) as compared to a control product (CP) for the prevention of heartworm disease when administered monthly for 11 consecutive months. METHODS: In this 11-month field study, 319 dogs ≥ 8 weeks old confirmed to be heartworm-negative were enrolled from eight geographically distinct US veterinary clinics, including sites in the southern USA and Mississippi River Valley. The dogs were treated with either the IP combination product at 0.75-1.53 mg/kg milbemycin oxime and 20-41.5 mg/kg lotilaner (n = 159) or the CP (Sentinel® Flavor Tabs®; milbemycin oxime/lufenuron) at the label-recommended dose rate (n = 158.) On day 330, effectiveness was evaluated in each dog using antigen and microfilarial (modified Knott's) testing to assess the establishment of any patent adult heartworm infections. RESULTS: All dogs treated with the IP combination product and the CP tested negative (100% prevention) for heartworm infection on day 330. The IP combination product tablets containing milbemycin oxime and lotilaner were well tolerated based on the safety assessments in all treated dogs. CONCLUSIONS: This multi-site clinical study using client-owned dogs demonstrated that monthly use of flavored, chewable tablets containing a combination of milbemycin oxime and lotilaner administered orally under end use conditions is safe for dogs. None of the enrolled dogs developed heartworm infections. Eleven consecutive monthly treatments of the IP provided 100% prevention of heartworm disease caused by D. immitis.