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• Efficacy of three consecutive monthly doses of selamectin/sarolaner was compared with one dose of fluralaner. • Based on geometric means, both selamectin/sarolaner and fluralaner provided >90% control of Ixodes scapularis for 84 days. • There were no adverse reactions to treatment with selamectin/sarolaner or fluralaner. The efficacy of three consecutive monthly treatments with a novel topical product (Revolution® Plus/Stronghold® Plus, Zoetis) containing selamectin in combination with the isoxazoline, sarolaner, was compared with that of another topical isoxazoline, fluralaner [Bravecto® (fluralaner topical solution) for Cats, Merck] against Ixodes scapularis ticks on cats. Twenty-four cats were ranked by pre-treatment tick counts to form groups of three and were randomly allocated to be treated with placebo, the minimum label dosage of Revolution® Plus (6 mg/kg selamectin plus 1 mg/kg sarolaner) or the minimum label dosage of Bravecto® for Cats (40 mg/kg fluralaner) within the groups. On Days 0, 30, and 60, each cat in the placebo and Revolution® Plus-treated groups was treated topically, whereas cats in the Bravecto® for Cats-treated group were treated topically once on Day 0 with fluralaner and, subsequently, these animals were treated with the placebo on Days 30 and 60 to maintain masking. Doses were calculated based on weight to provide the minimum label dosage for each product; the calculated volume of product to be administered was rounded off to the nearest 0.1 mL. The selamectin plus sarolaner-treated cats received effective dosages of 5.29–7.12 mg/kg selamectin and 0.88–1.19 mg/kg sarolaner, while the fluralaner cats received dosages of 35.21–43.16 mg/kg fluralaner. Cats were infested with approximately 50 unfed viable adult I. scapularis ticks on Days 5, 12, 26, 40, 54, 68, 82, and 88. Efficacy was assessed at 48 h after each infestation. There were no adverse reactions to any treatment during the study. The placebo-treated cats maintained adequate tick infestations throughout the study. Three monthly treatments with selamectin plus sarolaner (Revolution® Plus) resulted in high and consistent efficacy against I. scapularis for up to 30 days after each treatment. Based on geometric means, efficacy was ≥99.1% at all time points assessed. Treatment with fluralaner (Bravecto® for Cats) provided high and consistent efficacy of ≥99.3% up to Day 70. On Day 84, efficacy was 90.1%; however, cats from which ticks were recovered on Day 84 had received approximately 4%–12% less than the minimum dosage of 40 mg/kg fluralaner. Three consecutive monthly treatments with Revolution® Plus or a single treatment with Bravecto® for Cats provided >90% control of I. scapularis ticks over a 12-week time period. [ABSTRACT FROM AUTHOR]

• Efficacy was assessed against three ticks found on cats in the US. • Treatment with selamectin plus sarolaner resulted in >90% control of existing infestations. • Persistent efficacy of >90% was achieved for at least 4 weeks. • Treatment with selamectin alone provided little if any efficacy. The efficacy of a single topical application of a combination product containing selamectin and sarolaner (selamectin/sarolaner; Revolution® Plus/Stronghold® Plus) was evaluated in seven laboratory studies against Ixodes scapularis (three studies), Dermacentor variabilis (two studies), or Amblyomma maculatum (two studies). In each study, cats were randomly allocated to treatment groups based on pre-treatment host-suitability tick counts. On Days -2, 5, 12, 19, 26 and 33, the cats were infested with unfed adult ticks. On Day 0, cats were treated with either a placebo (vehicle control) or with the spot-on solution at the minimum dose of 6.0 mg selamectin and 1.0 mg sarolaner/kg bodyweight. In one study with I. scapularis and one with D. variabilis an additional group of cats was treated with selamectin alone (Revolution®, Zoetis) at 6.0 mg/kg bodyweight. Tick counts were conducted after treatment and after each weekly re-infestation and efficacy determined relative to placebo-treated animals. There were no treatment-related adverse reactions in any of the studies. Geometric mean live tick counts were significantly (P < 0.05) lower in the selamectin/sarolaner-treated groups compared to the geometric mean tick counts in the placebo-treated groups at all time-points in all studies. For all species, a single topical administration of the selamectin/sarolaner combination resulted in>90% efficacy against existing infestations based on geometric means. Efficacy against weekly re-infestations was >90% based on geometric means for at least 5 weeks for I. scapularis and D. variabilis , and for at least 4 weeks against A. maculatum. Selamectin alone had no efficacy against I. scapularis , where counts on selamectin-treated cats were not significantly different from placebo at all time points (P > 0.05), and for D. variabilis , counts were not significantly different from placebo at 2, 3 and 5 weeks after treatment (P > 0.05) and efficacy was never greater than 85%. Thus, the activity of the sarolaner against three common tick species found on cats in the US is complementary to the existing broad-spectrum parasite control of selamectin. The inclusion of sarolaner with selamectin in a combination product (Revolution® Plus/Stronghold® Plus) provides for the treatment of existing tick infestations and gives at least one month of control against re-infestation following a single topical application. [ABSTRACT FROM AUTHOR]

Background: The lone star tick, Amblyomma americanum, infests dogs and cats in North America and transmits the pathogens Ehrlichia chaffeensis and Ehrlichia ewingii, which cause monocytic and granulocytic ehrlichiosis in dogs and humans, and Cytauxzoon felis which causes cytauxzoonosis in cats. A parasiticide's speed of kill is important to minimize the direct deleterious effects [related to blood-feeding] of tick infestation and reduce the risk of transmission of tick-borne pathogens. In this study the speed of kill of sarolaner (Simparica™ Chewables) administered monthly for 3 months against A. americanum on dogs was evaluated and compared with a single dose of fluralaner (Bravecto®) for 13 weeks. Methods: Based on pretreatment tick counts, 24 dogs were randomly allocated to treatment with placebo or sarolaner at the label rate (2 to 4 mg/kg) on Days 0, 30 and 60 or with fluralaner (25 to 56 mg/kg) once according to manufacturer's instructions on Day 0. Dogs were examined and live ticks counted at 8, 12, and 24 h after treatment and subsequent re-infestations on Days 14, 28, 42, 58, 76 and 90. Acaricidal efficacy was determined at each time point relative to counts for placebo dogs. Results: Monthly oral doses of sarolaner provided > 95 % efficacy within 24 h of treatment, and consistently provided > 70 % efficacy against subsequent re-infestations with ticks within 24 h over the entire treatment period. Significantly more live ticks were recovered from fluralaner-treated dogs than from sarolaner-treated dogs at 24 h after re-infestation from Day 42 onwards. At 24 h, efficacy of fluralaner was = 20 % from Day 42 to the end of the study on Day 90. There were no adverse reactions to treatment. Conclusions: In this controlled laboratory evaluation, monthly treatment with sarolaner provided consistent efficacy against A. americanum with > 70 % of ticks killed within 24 h after a single oral dose over the duration of the study. Monthly treatment with sarolaner consistently killed significantly more ticks within 24 h than a single dose of fluralaner from 6 weeks after initial treatment. [ABSTRACT FROM AUTHOR]

Background: The brown dog tick, Rhipicephalus sanguineus sensu lato, commonly infests dogs globally, is the major vector of the pathogen that causes canine monocytic ehrlichiosis and also transmits Babesia vogeli. A rapid speed of kill of a parasiticide is essential to reduce the direct deleterious effects of tick infestation and the risk of tick-borne pathogen transmission. The speed of kill of a novel orally administered isoxazoline parasiticide, sarolaner (Simparica™), against R. sanguineus sensu lato on dogs was evaluated and compared with afoxolaner (NexGard®) for 5 weeks after a single oral dose. Methods: Based on pretreatment tick counts, 24 dogs were randomly allocated to oral treatment with either placebo, or label doses of sarolaner (2-4 mg/kg) or afoxolaner (2.5-6.8 mg/kg). Dogs were examined and live ticks counted at 8, 12, and 24 h after treatment and subsequent re-infestations on Days 7, 14, 21, 28, and 35. Efficacy was determined at each time point relative to counts for placebo dogs. Results: There were no adverse reactions to treatment. Based on geometric means, sarolaner provided >94 % efficacy within 8 h of treatment, and >99 % after 12 and 24 h. Against subsequent weekly re-infestations of ticks, sarolaner achieved ≥91.7 % efficacy (based on geometric means) to Day 35 at 24 h. Sarolaner significantly reduced tick counts versus placebo on Days 0 and 28 at 8 h (P ≤ 0.0390), on Days 0 to 14 and 28 at 12 h (P ≤ 0.0142), and on all days at 24 h (P < 0.0001). By comparison, tick counts for afoxolaner were significantly lower than placebo at 8 h on Days 0 and 28 (P ≤ 0.0117), at 12 h on Day 0 only (P < 0.0001), and on all days at 24 h (P ≤ 0.0078). Significantly more live ticks were recovered from afoxolaner-treated dogs than from sarolaner-treated dogs at 8 and 12 h after treatment (P ≤ 0.0286), at 12 h after re-infestation on Days 7 and 28 (P ≤ 0.04630), and at 24 h after re-infestations from Day 7 to Day 35 (P ≤ 0.0119). At 24 h, efficacy (based on geometric mean counts) of afoxolaner was less than 90 % from Day 7 onwards, and declined to less than 45 % by Day 35, while efficacy for sarolaner was >90 % for 35 days. Conclusions: In this controlled laboratory evaluation, sarolaner had a faster speed of kill against R. sanguineus sensu lato than afoxolaner. The rapid and consistent kill of ticks within 24 h after a single oral dose of sarolaner over 35 days indicates that this treatment will provide highly effective and reliable control of ticks over the entire treatment interval and should reduce the risk of tick-borne pathogen transmission. [ABSTRACT FROM AUTHOR]

Background: The black-legged (or deer) tick, Ixodes scapularis, commonly infests dogs and cats in North America and is the main vector for the pathogen that causes Lyme disease in dogs and humans. The speed of kill of a parasiticide is critical to minimize the direct and deleterious effects of tick infestation and especially to reduce the risk of tick-borne pathogen transmission. In this study, speed of kill of a novel orally administered isoxazoline parasiticide, sarolaner chewable tablets (Simparica™), against I. scapularis on dogs was evaluated and compared with afoxolaner (NexGard®) for five weeks after a single oral dose. Methods: Twenty four dogs were randomly allocated to treatment with either placebo, sarolaner (2 to 4 mg/kg), or afoxolaner (2.5 to 6.8 mg/kg) based on pretreatment tick counts. Dogs were examined and live ticks counted at 8, 12, and 24 h after treatment and subsequent re-infestations on Days 7, 14, 21, 28 and 35. Efficacy was determined at each time point relative to counts for placebo dogs. Results: A single oral dose of sarolaner provided >99 % efficacy within 24 h of treatment and >95 % against subsequent weekly re-infestations of ticks consistently to Day 35. For the earlier time points, sarolaner significantly reduced tick counts versus placebo from Day 0 to Day 21 at 8 and 12 h, and on Day 35 at 12 h (P ≤ 0.0174), while afoxolaner was only significantly lower at 8 h on Days 0 and 14 (P ≤ 0.0309), and at 12 h on Day 0 only (P < 0.0001). Significantly more live ticks were recovered from afoxolaner-treated dogs than from sarolaner-treated dogs at 24 h after infestation from Day 14 to Day 35 (P ≤ 0.0278). At 24 h, efficacy (based on geometric mean counts) of afoxolaner declined to less than 80 % from Day 21 through the end of the study, while efficacy for sarolaner was >95 % for 35 days. There were no adverse reactions to treatments. Conclusions: In this controlled laboratory evaluation, sarolaner had a faster speed of kill against I. scapularis than afoxolaner. This was noticeably more pronounced towards the end of the monthly treatment period. The rapid and consistent kill of ticks provided by sarolaner within 24 h after a single oral dose and re-infestation over 35 days suggests this treatment will provide highly effective and reliable control of ticks over the entire treatment interval, and should reduce the risk of tick-borne diseases, including Lyme disease whose agent is vectored by I. scapularis. [ABSTRACT FROM AUTHOR]

• Efficacy of one dose of fluralaner was compared with three consecutive monthly doses of selamectin/sarolaner. • Based on geometric means, selamectin/sarolaner provided 98.6%–100% control of Ctenocephalides felis for 84 days. • Fluralaner resulted in 94.6–100% control for 84 days. • No treatment-related adverse events were noted during the study. In a controlled laboratory study, the efficacy against fleas, Ctenocephalides felis , of a single treatment of fluralaner topical solution (Bravecto® for Cats, Merck) was compared with that of three consecutive monthly topical treatments with selamectin and sarolaner (Revolution® Plus, Zoetis). Twenty-four domestic short hair cats were ranked based on host suitability flea counts to form groups of three and were randomly assigned within group to one of three treatments. The first group received a topical treatment with (a) placebo (vehicle control for Revolution® Plus) on Days 0, 30, and 60, (b) 6 mg/kg selamectin and 1 mg/kg sarolaner on Days 0, 30, and 60, or (c) 40 mg/kg fluralaner on Day 0 and placebo (vehicle control for Revolution® Plus) on Days 30 and 60. Because doses were rounded off, the selamectin plus sarolaner-treated cats received effective dosages of 5.25–6.60 mg/kg selamectin and 0.88–1.10 mg/kg sarolaner, while the fluralaner-treated cats received dosages of 34.71–43.08 mg/kg fluralaner. All cats were infested with 100 (±5) fleas on Day -1 and at biweekly intervals after that, from Day 13 to Day 89. Flea comb counts were conducted 24 hours after treatment or after re-infestation. There were no adverse events related to treatment during the study. Except for a single cat from which 20 fleas were recovered on Day 90, all other placebo-treated cats had at least 48 fleas at each count, indicating adequacy of infestation of the controls. Based on geometric mean live flea counts, three consecutive monthly treatments with Revolution® Plus resulted in consistent and high efficacy of ≥98.6% compared with placebo throughout the study. A single treatment with Bravecto® for Cats provided consistent and high efficacy of ≥94.6% on all count days during a period of 12 weeks, the approved duration of efficacy for the product. Based on the efficacy results of the study, both products were equivalent in their ability to control fleas on cats. Use of Bravecto® for Cats every 12 weeks or the consecutive monthly use of Revolution® Plus is expected to provide extended high residual kill over the respective labeled durations of efficacy of the two products. [ABSTRACT FROM AUTHOR]

The efficacy of a single oral treatment with sarolaner (Simparica™, Zoetis), a novel isoxazoline compound, was evaluated against five tick species known to infest dogs in the United States. A total of 10 laboratory studies, two against each species, were conducted using adult purpose-bred mongrels or Beagle dogs. In each study, 16 dogs were randomly allocated to one of two treatment groups based on pre-treatment host-suitability tick counts. Dogs were infested with approximately 50 unfed adult Amblyomma americanum, Amblyomma maculatum, Dermacentor variabilis, Ixodes scapularis or Rhipicephalus sanguineus ticks on Days -2, 5, 12, 19, 26 and 33. On Day 0, dogs were treated with a placebo or a sarolaner tablet providing a minimum dose of 2 mg/kg. Tick counts were conducted 48 h after treatment and after each subsequent weekly re-infestation. There were no treatment-related adverse reactions during any of the studies. Dogs in the placebo-treated group maintained tick infestations throughout the studies. Geometric mean live tick counts were significantly lower ( P ≤0.0001) in the sarolaner-treated group compared to the tick counts in the placebo group at all timepoints. Treatment with sarolaner resulted in ≥99.6% efficacy against existing infestations of all five tick species within 48 h. The efficacy against weekly post-treatment re-infestations of all tick species was ≥96.9% for at least 35 days after treatment. Thus, a single dose of sarolaner administered orally at the minimum dosage of 2 mg/kg, resulted in excellent efficacy within 48 h against existing tick infestations, and against weekly re-infestations for 35 days after treatment. These studies confirmed that administration of the minimum dose of sarolaner will provide rapid treatment of existing infestations and give at least one month of control against re-infestation by the common tick species affecting dogs in the US. [ABSTRACT FROM AUTHOR]

Four studies were conducted to evaluate the speed of kill, effect on egg production, and efficacy in a simulated infested-home environment of a novel isoxazoline, sarolaner (Simparica™, Zoetis), against fleas on dogs. Individually identified and housed, purpose-bred Beagles were used in each study and were allocated randomly to groups based on pretreatment parasite counts. In two speed of kill studies, groups of dogs infested with 100 fleas prior to treatment were treated orally with placebo or sarolaner tablets providing the minimum dose of 2 mg/kg and then re-infested with fleas weekly for five weeks post-treatment. Comb counts were conducted to determine the numbers of viable fleas at one to three, four, eight and 12 h after treatment and each subsequent infestation. In the egg production study, sarolaner- and placebo-treated dogs were similarly challenged with fleas and at 48 h after each infestation the dogs were housed for 20 h in cages allowing the collection and counting of all flea eggs produced during this period. Collected eggs were incubated to evaluate hatch and development to adults. The last study used dogs housed in a flea-infested simulated-home environment. Dogs were allocated to treatment with either placebo or sarolaner tablets providing a dose of 2 mg/kg once a month for three treatments. Flea infestations were assessed by comb counts (fleas were replaced on the dogs) on Days 14, 30, 44, 60, 74 and 90. The speed of kill studies demonstrated that a single 2 mg/kg oral dose of sarolaner started killing fleas within three to four hours after treatment or subsequent re-infestations for up to a month, and achieved ≥98% control of fleas by eight hours after treatment or re-infestation for 28 days. In the study to assess effects on flea reproduction, a single oral treatment of sarolaner resulted in the complete cessation of egg-laying for 35 days. This rapid kill of fleas and inhibition of reproduction were confirmed in a simulated-home environment where the existing infestations were reduced by >95% within two weeks of the first treatment and eliminated from the dogs after two monthly doses. [ABSTRACT FROM AUTHOR]