Efficacy of sarolaner (Simparica®) against induced infestations of Haemaphysalis longicornis on dogs.

BACKGROUND: Haemaphysalis longicornis is the major tick affecting dogs in most of the East Asia/Pacific region and has recently been detected in a number of areas of the USA. This tick is a vector for a number of pathogens of dogs, other mammals and humans. In this study, the efficacy of a single oral administration of sarolaner (Simparica®, Zoetis) at the minimum label dosage (2 mg/kg) was evaluated against an existing infestation of H. longicornis and subsequent weekly reinfestations for 5 weeks after treatment. METHODS: Sixteen dogs were ranked on pretreatment tick counts and randomly allocated to treatment on Day 0 with sarolaner at 2 mg/kg or a placebo. The dogs were infested with H. longicornis nymphs on Days - 2, 5, 12, 19, 26 and 33. Efficacy was determined at 48 hours after treatment and subsequent re-infestations based on live tick counts relative to placebo-treated dogs. RESULTS: There were no adverse reactions to treatment. A single dose of sarolaner provided 100% efficacy on Days 2, 7, 14 and 21; and ≥ 97.4% efficacy on Days 28 and 35. Considering only attached, live ticks, efficacy was 100% for the entire 35 days of the study. Geometric mean live tick counts for sarolaner were significantly lower than those for placebo on all days (11.62 ≤ t(df) ≤ 59.99, where 13.0 ≤ df ≤ 14.1, P < 0.0001). CONCLUSIONS: In this study, a single oral administration of sarolaner at 2 mg/kg provided 100% efficacy against an existing infestation of H. longicornis nymphs and ≥ 97.4% efficacy (100% against attached ticks) against weekly reinfestation for at least 35 days after treatment.

Preventive efficacy of oral moxidectin at various doses and dosage regimens against macrocyclic lactone-resistant heartworm (Dirofilaria immitis) strains in dogs.

BACKGROUND: Moxidectin has previously shown limited efficacy (≤ 44.4%) against confirmed macrocyclic lactone (ML)-resistant Dirofilaria immitis strains at 3 µg/kg after single and multiple oral dosages. Three studies were conducted to evaluate higher oral moxidectin doses for efficacy against confirmed ML-resistant D. immitis strains. METHODS: Dogs were inoculated with 50 D. immitis L3 and randomly allocated to treatments. Study 1: 6 groups of dogs (n = 8) were inoculated with JYD-34 (Day - 30) and treated as follows: T01, negative control; T02-T05, moxidectin at 3, 6, 12 or 24 µg/kg, respectively, on Day 0 only; T06, moxidectin at 3 µg/kg on Days 0, 30 and 60. Study 2: 10 groups of dogs (n = 5) were inoculated (Day - 30) with either JYD-34 (T01, T03-05) or ZoeLA (T02, T06-T10) and treated as follows: T01 and T02, negative controls; T03-T05, moxidectin at 24, 40 or 60 µg/kg, respectively, on Days 0, 28 and 56; T06 and T09, moxidectin at 3 or 60 µg/kg on Day 0 only; T07, T08 and T10, moxidectin at 24, 40 or 60 µg/kg, respectively, on Days 0, 28 and 56. Study 3: 5 groups of dogs (n = 5) were inoculated with ZoeMO (Day - 28) and treated as follows: T01, negative control; T02, moxidectin at 3 µg/kg moxidectin on Day 0 only; T03-T05, moxidectin at 24, 40 or 60 µg/kg, respectively, on Days 0, 28 and 56. All dogs were necropsied for adult heartworm recovery ~ 4-5 months post-inoculation. RESULTS: All moxidectin-treated dogs showed significantly lower worm counts than controls. The efficacy of moxidectin administered once at 3 µg/kg was 19% (JYD-34), 44.4% (ZoeLA) and 82.1% (ZoeMO). Increasing both the dose and the number of dosages of moxidectin improved efficacy, with 100% protection obtained using three dosages of moxidectin at either 40 µg/kg (JYD-34, ZoeMO) or 60 µg/kg (ZoeLA). Three dosages of 24 µg/kg were also highly effective, providing ≥ 98.8% efficacy for all three strains. CONCLUSIONS: Increasing both the dose and number of consecutive monthly dosages of moxidectin improved the efficacy against ML-resistant heartworms. Based on these data and other technical considerations, the 24 µg/kg dose was considered the optimal dose for further commercial development.

Laboratory and field studies to investigate the efficacy of a novel, orally administered combination product containing moxidectin, sarolaner and pyrantel for the prevention of heartworm disease (Dirofilaria immitis) in dogs.

BACKGROUND: Dirofilaria immitis is a filarial parasite of dogs that can cause serious or fatal cardiopulmonary disease. Three studies were conducted to evaluate the efficacy and safety of monthly treatment with moxidectin in a chewable tablet product in combination with sarolaner and pyrantel to prevent heartworm disease in dogs after experimental challenge and in a clinical field study in the USA. METHODS: In two laboratory studies, dogs (8 per group) that had been inoculated 30 days prior with 50 third-stage D. immitis larvae were randomized to treatment on Day 0 with placebo or combination product, at the minimum dose of 24 µg/kg moxidectin, 2 mg/kg sarolaner and 5 mg/kg pyrantel (as pamoate salt). Study 2 also included groups treated with tablets containing moxidectin-alone (24 µg/kg) or sarolaner-alone (2 mg/kg). Efficacy was evaluated ~ 5 months after inoculation by adult heartworm counts at necropsy. In the field study, 410 dogs ≥ 8 weeks-old from 23 USA veterinary clinics were treated for 11 months with either combination product at 24-48 µg/kg moxidectin, 2-4 mg/kg sarolaner and 5-10 mg/kg pyrantel (n = 272) or Heartgard® Plus (ivermectin/pyrantel) at the label recommended dose rate (n = 138). Efficacy was evaluated on Day 330 using antigen and microfilaria testing to assess adult heartworm infection. RESULTS: In the laboratory studies, there were no heartworms recovered from any dog treated with the combination product or moxidectin alone and all dogs treated with placebo or sarolaner-alone were infected with 20-44 adult heartworms. In the field study, all dogs treated with the combination product tested negative for heartworm infection on Day 330, whereas two dogs treated with Heartgard® Plus tested positive. The Heartgard® Plus-treated dogs that tested heartworm positive were from the lower Mississippi River Valley region, where heartworm resistance has been confirmed to occur. The combination product was well tolerated in all studies. CONCLUSIONS: In laboratory studies, no heartworms were recovered from dogs treated with a single dose of the novel combination product containing moxidectin, sarolaner and pyrantel. Additionally, in the field study no dog tested positive for adult heartworm infection when dosed with the combination product monthly for 11 months, while two dogs treated with Heartgard® Plus tested positive.

Detection of tick-borne pathogens in ticks from dogs and cats in different European countries.

Ticks are known to transmit pathogens which threaten the health and welfare of companion animals and man globally. In the present study, mainly adult ticks were collected from dogs and cats presented at their local veterinary practice in Hungary, France, Italy, Belgium (dogs only) and Germany (cats only), and identified based on tick morphology. If more than one tick was collected from a host animal, ticks were pooled by tick species for DNA extraction and subsequent PCR examination for the presence of tick-borne pathogens. Out of 448 tick samples, 247 (95 from dogs and 152 from cats) were Ixodes ricinus, 26 (12 from dogs and 14 from cats) were I. hexagonus, 59 (43 from dogs and 16 from cats) were Dermacentor reticulatus and 116 (74 from dogs and 42 from cats) were Rhipicephalus sanguineus sensu lato (s.l.). In 17% of the I. ricinus samples Anaplasma phagocytophilum was found. Borrelia spp. were mainly identified in I. ricinus collected from cats (18%) and to a lesser extent in dog-sourced ticks (1%), with Borrelia afzelii (n = 11), B. garinii (n = 7), B. valaisiana (n = 5), B. lusitaniae (n = 3) and B. burgdorferi sensu stricto (n = 3) being identified. One I. hexagonus sample collected from a cat in France tested positive for B. afzelii. Babesia canis was detected in 20% of the D. reticulatus samples, mainly from Hungary. Rhipicephalus sanguineus s.l. was found positive for Hepatozoon canis (3%), A. platys (5%) and three Rickettsia species (7%; R. massiliae; R. raoultii and R. rhipicephali). Furthermore, a total of 66 R. sanguineus s.l. ticks were subjected to molecular analysis and were identified as R. sanguineus sp. II-temperate lineage, with seven haplotypes recorded. Amongst them, the most prevalent sequence types were haplotype XIII (n = 24; 69%) and haplotype XIV (n = 16; 52%) in France and in Italy, respectively, found both in cats and dogs. Although differences related to both country and host, were observed, the results of this study indicate that cats and dogs are exposed to tick-borne pathogen infected ticks, which may represent a medical risk to these host animals.

Efficacy of oral moxidectin against susceptible and resistant isolates of Dirofilaria immitis in dogs.

BACKGROUND: Monthly topical and sustained-release injectable formulations of moxidectin are currently marketed; however, an oral formulation, while approved at a dose of 3 µg/kg, is not currently marketed in the United States. Although resistance of heartworms to all macrocyclic lactone (ML) heartworm preventives (ivermectin, milbemycin, selamectin and moxidectin) has been demonstrated, to date no data have been reported on the effectiveness of oral moxidectin against recent isolates of Dirofilaria immitis. METHODS: A total of nine studies were conducted to determine the efficacy of moxidectin against a range of older and recently sourced heartworm isolates. Dogs (groups of three to eight) were inoculated with 50 D. immitis infective larvae (L3) from nine different isolates (MP3, Michigan, JYD-34, ZoeMO-2012, ZoeKy-2013, ZoeLA-2013, GCFL-2014, AMAL-2014 and ZoeAL-2015) and treated 28-30 days later with single oral doses of 3 µg/kg of moxidectin. Additionally, one group of dogs that was inoculated with JYD-34 was treated monthly for 3 consecutive months beginning 30 days post inoculation. Dogs were held for approximately 4 months after the initial (or only) treatment and then necropsied for recovery of adult heartworms. RESULTS: A single dose of 3 µg/kg of moxidectin was 100% effective in preventing the development of five of nine heartworm isolates (MP3, Michigan, ZoeKy, GCFL and ZoeAL isolates), confirming their susceptibility to oral moxidectin at this dose. MP3 and Michigan are isolates sourced from the field more than 9 years ago, while ZoeKy, ZoeAL and GCFL were isolated from the field within the past 2 to 3 years. Against JYD-34, ZoeMO, ZoeLA and AMAL isolates, a single dose of 3 µg/kg of moxidectin was not completely effective, with efficacies of 19%, 82%, 54% and 62%, respectively, demonstrating resistance of these heartworm isolates to oral moxidectin at this dosage. Three consecutive monthly doses of 3 µg/kg of moxidectin were also incompletely effective against the JYD-34 isolate, with an efficacy of 44%. JYD-34 was originally isolated in 2010, while ZoeMO, ZoeLA and AMAL were isolated within the past 2 to 3 years. CONCLUSIONS: A single oral dose (3 µg/mg) of moxidectin was 100% effective in preventing the development of ML-susceptible heartworm isolates while being incompletely effective against ML-resistant isolates.

Efficacy of sarolaner (Simparic™) against induced infestations of Amblyomma cajennense on dogs.

BACKGROUND: Amblyomma cajennense is the main vector of Rickettsia rickettsii which causes Brazilian spotted fever. This adult tick preferably infests horses and capybaras, but has low host specificity during its immature stages, thus posing a threat to humans and dogs. In this study, the efficacy of sarolaner (Simparic™/Simparica®, Zoetis) when administered once orally to dogs at 2 mg/kg was evaluated against induced infestations of A. cajennense nymphs for up to 35 days after treatment. METHODS: Based on pretreatment tick counts, 20 dogs were randomly allocated to treatment with sarolaner (Simparic™) dosed at 2 mg/kg of body weight or a placebo on Day 0 of the study. Artificial infestations were performed using laboratory raised A. cajennense nymphs on study days -2, 5, 12, 19, 26 and 33. Efficacy was determined at 48 h post-treatment or post-infestation at each time point relative to the counts for dogs that received placebo. RESULTS: There were no adverse reactions to treatment. A single dose of sarolaner (Simparic™) provided 100% efficacy on study days 2, 7 and 14; and ≥ 99.6% on days 21, 28 and 35. Geometric mean live tick counts for sarolaner were significantly lower than those for placebo on all days (P < 0.0001). CONCLUSIONS: Under the conditions of the present study, sarolaner (Simparic™) administered once orally at 2 mg/kg provided 100% efficacy against existing infestations and ≥ 99.6% efficacy within 48 h against weekly challenges of A. cajennense for at least 35 days after treatment.

Efficacy and safety of sarolaner (Simparica®) in the treatment and control of naturally occurring flea infestations in dogs presented as veterinary patients in Australia.

BACKGROUND: The efficacy and safety of a novel isoxazoline compound, sarolaner (Simparica®, Zoetis) and spinosad (Comfortis®, Elanco) as a positive control were evaluated for the treatment and control of natural flea infestations on dogs in two randomised, blinded, multi-centric clinical trials conducted in 11 veterinary clinics in northeastern and southeastern states of Australia. METHODS: A total of 162 client-owned dogs (80 in northern study and 82 in southern study) from 105 households were enrolled. Each household was randomly allocated to receive either sarolaner (Simparica®, Zoetis) or spinosad (Comfortis®, Elanco). Dogs were dosed on Days 0, 30 and 60 and physical examinations and flea counts were conducted on Days 0, 14, 30, 60 and 90. Efficacy assessments were based on the percentage reduction in live flea counts post-treatment compared to Day 0. RESULTS: In the northern study, at enrolment, primary dogs had flea counts ranging from 5 to 772. At the first efficacy assessment on Day 14, sarolaner resulted in 99.3% mean reduction in live flea counts relative to Day 0, compared to 94.6% in the spinosad group. On Day 30, the sarolaner-treated group had mean efficacy of 99.2% compared to 95.7% in the spinosad-treated group, and on days 60 and 90, both groups had mean efficacies of ≥ 98.8%. In the southern study, at enrolment, primary dogs had flea counts ranging from 5 to 156. Both sarolaner and spinosad resulted in ≥ 96.7% mean reduction in live flea counts on Day 14. On Day 30, the sarolaner-treated group had mean efficacy of 99.5% compared to 89.7% in the spinosad-treated group, and on days 60 and 90, both groups had mean efficacies of ≥ 98.6%. No treatment-related adverse events were observed in either study. CONCLUSIONS: A single monthly dose of sarolaner (Simparica®) administered orally at 2-4 mg/kg for three consecutive months was well tolerated and provided excellent efficacy against natural infestations of fleas under a range of Australian field conditions including different climatic and housing conditions. Similar efficacy was observed with spinosad (Comfortis®) after the second and third monthly treatments.

Response to the Letter to the Editor by Rob Armstrong.

In a recent Letter to the Editor, Armstrong raises concern that the design of the study reported by Six et al. was not consistent with the product label for treatment of Amblyomma americanum, since fluralaner was not re-administered 56 days after the initial treatment. The Authors disagree with this assessment and confirm that the design was appropriate, and therefore the results and conclusions for the entire study period are valid.

Comparative speed of kill of sarolaner (Simparica™ Chewables) and fluralaner (Bravecto(®)) against induced infestations of Amblyomma americanum on dogs.

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.

Efficacy of a novel oral formulation of sarolaner (Simparica™) against four common tick species infesting dogs in Europe.

The efficacy of single oral treatment of sarolaner (Simparica™, Zoetis), a novel isoxazoline compound, was evaluated against four tick species known to commonly infest dogs in Europe. Eight laboratory studies were conducted using adult purpose-bred Beagle dogs. In each study, 16 animals were randomly allocated to one of two treatment groups based on pre-treatment host-suitability tick counts. Dogs were infested with 50 unfed adult Dermacentor reticulatus (two studies), Ixodes hexagonus (three studies), Ixodes ricinus (two studies) or Rhipicephalus sanguineus (one study) ticks on Days -2, 5, 12, 19, 26 and 33. On Day 0, dogs were treated orally with placebo or sarolaner tablets providing the minimum dose of 2.0mg/kg bodyweight and tick counts were conducted 48h after treatment and after each subsequent weekly re-infestation. There were no treatment-related adverse reactions in any of the studies. Dogs in the placebo-treated group maintained tick infestations throughout the studies. Geometric mean live tick counts were significantly (P≤0.0001) lower in the sarolaner-treated group compared to the tick counts in the placebo group at all time-points. A single oral administration of sarolaner resulted in 100% efficacy against existing infestations of all tick species except R. sanguineus, for which the efficacy was 99.7%, within 48h. Efficacy against weekly re-infestations was ≥97.5% for all tick species for 35 days. Thus, a single dose of sarolaner administered orally at the minimum dosage of 2 mg/kg, resulted in ≥99.7% efficacy within 48h against existing tick infestations, and in ≥97.5% efficacy against weekly re-infestations, for at least 35 days after treatment. These studies confirmed that administration of the minimum dose of sarolaner will provide treatment of existing infestations and give at least one month of control against re-infestation by the common tick species affecting dogs in Europe.

Evaluation of the speed of kill, effects on reproduction, and effectiveness in a simulated infested-home environment of sarolaner (Simparica™) against fleas on dogs.

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 2mg/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 12h after treatment and each subsequent infestation. In the egg production study, sarolaner- and placebo-treated dogs were similarly challenged with fleas and at 48h after each infestation the dogs were housed for 20h 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 2mg/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 2mg/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.

Efficacy of sarolaner, a novel oral isoxazoline, against two common mite infestations in dogs: Demodex spp. and Otodectes cynotis.

The efficacy of sarolaner (Simparica™, Zoetis) was evaluated against Demodex spp. in dogs with generalized demodicosis and against Otodectes cynotis (otodectic mange) in dogs with induced infestations. In the first study, 16 dogs with clinical signs of generalized demodicosis and positive for Demodex spp. mites were randomly assigned to treatment with either sarolaner (2mg/kg) orally on Days 0, 30 and 60, or topical imidacloprid (10mg/kg) plus moxidectin (2.5mg/kg) solution every 7 days from Day 0 to Day 81. For sarolaner-treated dogs, pretreatment mite counts were reduced by 97.1% at 14days and 99.8% by 29 days after the first dose, with no live mites detected thereafter. Weekly imidacloprid plus moxidectin resulted in 84.4 and 95.6% reduction at these two time points, respectively, with no mites detected from Day 74 on. All dogs in both groups showed marked improvement in the clinical signs of demodicosis. In the second study, 32 dogs with induced infestations of O. cynotis were randomly assigned (eight per group) to oral sarolaner (2mg/kg) as a single treatment on Day 0 or as a two dose regime (Days 0 and 30), or a placebo group for each of the dose regimes. Sarolaner administered at 2mg/kg as a single oral dose resulted in a 98.2% reduction at Day 30 and two doses of sarolaner, administered one month apart, resulted in a 99.5% reduction in ear mites at Day 60 compared to placebo controls. There were no treatment related adverse events in either study. In these studies, sarolaner at an oral dose of 2mg/kg was highly effective in reducing the live mite counts associated with a natural infestation of Demodex spp. and an induced infestation of O. cynotis. In addition, the Demodex-infested dogs showed a marked improvement in the clinical signs of generalized demodicosis.

Efficacy and safety of a novel oral isoxazoline, sarolaner (Simparica™) in the treatment of naturally occurring flea and tick infestations in dogs presented as veterinary patients in Europe.

Two randomised, blinded, multi-centered field studies were conducted in Europe to demonstrate the efficacy and safety of three monthly oral doses of sarolaner (Simparica™, Zoetis) administered at a minimum dosage of 2.0mg/kg (range 2-4mg/kg) against natural flea or tick infestation of dogs presented as veterinary patients. In the flea study, the improvement in clinical signs associated with flea allergy dermatitis (FAD) was also investigated. The palatability of the sarolaner chewable tablet formulation was evaluated in both studies. Spinosad (Comfortis(®) Chewable Tablets, Elanco) and fipronil (Frontline(®) Spot on, Merial) were used as positive controls in the flea and tick study, respectively. Treatments were administered on Days 0, 30 and 60. Efficacy was calculated based on the mean percent reduction of live parasite counts on post-treatment days 14, 30, 60 and 90 versus the pre-treatment count on Day 0. Non-inferiority of sarolaner to the control products was assessed at each time-point using a margin of 15% at the one-sided 0.025 significance level. Dogs were enrolled in a 2:1 ratio (sarolaner:comparator); 285 flea- and 181 tick-infested dogs were assessed for efficacy and safety, and 137 and 48 dogs were assessed for safety only, in the flea and tick study, respectively. There were no treatment-related adverse events. Efficacy against fleas was 98.8%, 99.4%, >99.9% and >99.9% in the sarolaner-treated group and 98.9%, 93.7%, 96.8% and 95.1% in the spinosad-treated group on Days 14, 30, 60 and 90, respectively. Sarolaner was non-inferior to spinosad at all time-points and was superior on Day 30. For the 42 dogs identified as having FAD at enrolment, the clinical signs of FAD improved in all dogs and the incidence was markedly reduced by the end of the study. Efficacy against ticks was 97.4%, 97.6%, 99.8% and 100% in the sarolaner-treated group and 94.1%, 88.5%, 89.9% and 98.1% in the fipronil-treated group on Days 14, 30, 60 and 90, respectively. Sarolaner was non-inferior to fipronil at all time-points, and was superior on Days 30 and 60. Sarolaner tablets were voluntarily and fully consumed within one minute in 93% of the 1280 occasions offered. Sarolaner administered orally at monthly intervals at a minimum dosage of 2 mg/kg was safe and highly effective against natural infestations of fleas and ticks on dogs. In addition, clinical signs FAD improved in dogs treated with sarolaner, and the flavored, chewable tablets were highly palatable.

Efficacy and safety of a novel oral isoxazoline, sarolaner (Simparica™), for the treatment of sarcoptic mange in dogs.

The efficacy of the novel isoxazoline, sarolaner (Simparica™) was investigated in dogs with clinical signs consistent with sarcoptic mange and harbouring natural infestations of Sarcoptes scabiei. One placebo-controlled laboratory study and one multi-centred field study with a commercial comparator containing imidacloprid/moxidectin (Advocate(®) spot-on) were conducted. Oral or topical treatments were administered on Days 0 and 30. Up to 10 skin scrapings were taken for the assessment of S. scabiei infestations from each dog before treatment and on Days 14, 30, 44 and 60 in the laboratory study, and on Days 30 and 60 in the field study. In the laboratory study, efficacy was calculated based on the percent reduction of mean live mite counts compared to the placebo group. In the field study parasitological cure rate (% dogs free of mites) was determined and non-inferiority of sarolaner to the control product was assessed. In the laboratory study 44 mixed breed dogs were enrolled in four batches. Due to decreasing mite counts in the placebo treated dogs, immunosuppression with dexamethasone (0.4mg/kg three times per week for two weeks) was initiated in all dogs on study at that time (n=6) and those subsequently enrolled (n=14). In the field study, dogs were enrolled in a 2:1 ratio (sarolaner:comparator); 79 dogs were assessed for efficacy and safety, and an additional 45 dogs were assessed for safety only. There were no treatment related adverse events in either study. In the laboratory study, no mites were found on any sarolaner-treated dogs 14 days after the first treatment except for one dog that had a single mite on Day 44. In the field study, the parasitological cure rate was 88.7% and 100% in the sarolaner group and 84.6% and 96.0% in the imidacloprid/moxidectin group, on Days 30 and 60, respectively. Statistical analysis showed that sarolaner was non-inferior to imidacloprid/moxidectin at both time points. The clinical signs of sarcoptic mange, including hair loss, papules, pruritus, erythema, and scaling/crusting improved throughout the study. Sarolaner was safe, achieved 100% reduction in the numbers of S. scabiei detected and resulted in marked improvement of the clinical signs of sarcoptic mange in dogs following two monthly oral administrations.

Evaluation of the speed of kill of sarolaner (Simparica™) against induced infestations of three species of ticks (Amblyomma maculatum, Ixodes scapularis, Ixodes ricinus) on dogs.

The rapid speed of kill of sarolaner (Simparica™, Zoetis), a novel isoxazoline compound, was demonstrated against three tick species known to infest dogs in Europe or the United States. Efficacy was measured against an existing infestation and against subsequent weekly re-infestations for 35 days after treatment. Dogs were randomly allocated to treatment with a single oral dose of either placebo or sarolaner (2mg/kg) based on pre-treatment host-suitability tick counts. Dogs were infested with approximately 50 unfed adult Ixodes scapularis, Ixodes ricinus or Amblyomma maculatum ticks on Days-2, 7, 14, 21, 28 and 35. Tick counts were conducted at 4 (I. scapularis only), 8, 12 and 24h after treatment on Day 0 and after each subsequent re-infestation. No treatment-related adverse reactions occurred during any of these studies. Dogs in the placebo-treated groups maintained adequate tick infestations (recovery of 20-70% of applied ticks) throughout the duration of the studies. Following treatment, live tick counts were significantly reduced relative to placebo at the 8h post treatment counts indicating that sarolaner started killing existing infestations of ticks rapidly after treatment. Efficacy was 90.1% against I. ricinus, 98.8% against I. scapularis, and 99.2% against A. maculatum within 12h, and 100% efficacy was achieved at 24h after treatment against all three tick species. This speed of kill was maintained throughout the month with ≥95.7%, ≥98.7% and ≥89.6% efficacy against I. scapularis, I. ricinus, and A. maculatum, respectively, at 24h after re-infestation at least through Day 28.

Efficacy of a novel oral formulation of sarolaner (Simparica™) against five common tick species infesting dogs in the United States.

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 48h 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 48h. 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 2mg/kg, resulted in excellent efficacy within 48h 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.

Evaluation of the effectiveness of a novel oral formulation of sarolaner (Simparica™) for the treatment and control of fleas on dogs.

The efficacy of a single oral dose of a novel isoxazoline, sarolaner (Simparica™, Zoetis), for the treatment and control of flea infestations on dogs was confirmed in five laboratory studies. The studies were conducted using adult purpose-bred Beagles and/or mixed breed dogs. All animals were individually identified and housed, and were allocated randomly to treatment with either placebo or sarolaner (eight to 10 per group) based on pretreatment parasite counts. Three studies used cat flea (Ctenocephalides felis felis) strains recently isolated from the field from the US, EU, or Australia; in the fourth study a laboratory strain (KS1) with documented tolerance to a number of insecticides such as fipronil, imidacloprid, and permethrin was used. In the fifth study, dogs were infested with dog fleas, Ctenocephalides canis. Dogs were treated orally on Day 0 with a placebo or a sarolaner tablet providing a minimum dose of 2mg/kg. Dogs were infested with approximately 100 unfed, adult fleas prior to treatment and at weekly intervals post-treatment. Comb counts were conducted to determine the numbers of viable fleas at 24h after treatment and after each subsequent infestation. Efficacy against C. felis and C. canis was 99.8-100% from treatment through Day 35. In all five studies, elimination of existing infestations was achieved within 24h after dosing, with only a single live C. felis found on one dog on Day 1. Similarly, control of flea challenges was achieved within 24h after infestation throughout the 35day study periods, with only single live C. felis found on two dogs on Day 28 in one study, and on a single dog on Day 35 in another study. There were no adverse reactions to treatment with sarolaner. These studies confirmed that a single oral dose of sarolaner at 2mg/kg provided highly effective treatment of existing C. felis infestations and persistent control of C. felis on dogs for 35days after treatment. Efficacy equivalent to that seen with C. felis was confirmed against C. canis and a known insecticide-tolerant strain of C. felis.

Determination of the effective dose of a novel oral formulation of sarolaner (Simparica™) for the treatment and month-long control of fleas and ticks on dogs.

Three laboratory studies were conducted to determine the appropriate dose of sarolaner, a novel isoxazoline, for the treatment and month-long control of infestations of fleas and ticks on dogs. In the first study, dogs were treated orally with sarolaner suspension formulations at 1.25, 2.5 or 5.0mg/kg, and infested with Dermacentor reticulatus, Rhipicephalus sanguineus ticks and with Ctenocephalides felis felis (cat flea) prior to treatment and then weekly for up to 8 weeks. Fleas and ticks were counted 48h after treatment and after each subsequent infestation at 24h for fleas and 48h for ticks. The lowest dose of sarolaner (1.25mg/kg) provided 100% efficacy against fleas from treatment through Day 35 and 98.4% at Day 56. This dose of sarolaner resulted in 99.7-100% control of both species of ticks through Day 28. In Study 2, dogs were dosed orally with placebo or sarolaner suspension formulations at 0.625, 1.25 or 2.5mg/kg and infested with Ixodes scapularis prior to treatment and weekly for 6 weeks, Amblyomma americanum (pretreatment and Day 26), Dermacentor variabilis (Day 33) and A. maculatum (Day 41). Ixodes scapularis was the most susceptible; the lowest dose (0.625mg/kg) providing>95% efficacy through Day 43. Efficacy against D. variabilis on Day 35 was>95% at 1.25 and 2.5mg/kg, whereas the 0.625mg/kg dose gave only 61.4% efficacy. Amblyomma spp. were the least susceptible ticks; efficacy of the 1.25mg/kg dose at Day 28 for A. americanum was markedly lower (88.5%) than achieved for D. reticulatus (100%) at Day 28 and also lower than for D. variabilis at Day 35 (96.2%). In Study 3, dogs were dosed orally with placebo or sarolaner in the proposed commercial tablet (Simparica™) at 1.0, 2.0 or 4.0mg/kg, and infested with A. maculatum, one of the ticks determined to be dose limiting, prior to treatment and then weekly for 5 weeks. All doses gave 100% control of the existing infestation. The two highest dosages resulted in >93% control of subsequent challenges for 5 weeks. There was no significant improvement in efficacy provided by the 4.0 mg/kg dose over the 2.0mg/kg dose (P>0.05) at any time point. The 2.0mg/kg dose was superior to the 1.0mg/kg on Day 14 (P=0.0086) and as efficacy for 1.0mg/kg declined below 90% at Day 28, a single 1mg/kg dose would not provide a full month of tick control. Thus, 2.0mg/kg was selected as the sarolaner dose rate to provide flea and tick control for at least one month following a single oral treatment.

Efficacy and safety of sarolaner (Simparica™) against fleas on dogs presented as veterinary patients in the United States.

The efficacy and safety of a novel isoxazoline parasiticide, sarolaner (Simparica™), for the control of fleas on dogs was evaluated in a randomized, controlled clinical study conducted in 19 general veterinary practices throughout the United States. Four hundred and seventy nine (479) dogs from 293 households were enrolled. Each household was randomly assigned to treatment with either sarolaner oral tablets (Simparica™, Zoetis) at the proposed label dose or an approved comparator product at the label dose (spinosad, Comfortis(®), Elanco). Dogs were dosed by their owners at home on Day 0 and on approximately Days 30 and 60. Dogs were examined at the clinics for general health, flea and tick infestation, and clinical signs of flea allergy dermatitis (FAD) at the initial visit and Days 14, 30, 60 and 90. Blood was collected for clinical pathology at screening and Day 90. Sarolaner was well-accepted by dogs with the majority of flavored chewable tablets (91.5%) accepted free choice, by hand or in food. Geometric mean live flea counts were reduced by >99% at the first time measured (14 days) after initiation of treatment and continued to reduce through the study. Treatment success (proportion of dogs with ≥90% reduction in fleas) for the sarolaner-treated dogs was superior to that for spinosad-treated dogs at Days 14 and 30 and non-inferior on Days 60 and 90 (P≤0.025) The rapid reduction in flea infestations resulted in a similar rapid resolution of the clinical signs associated with FAD. Sarolaner chewable tablets were well tolerated with no treatment related adverse reactions. Most of the clinical signs reported were consistent with allergies and dermatitis or sporadic occurrences of conditions commonly observed in the general dog population. A wide variety of concomitant medications, including many commercially available heartworm preventatives and other anthelmintic drugs, were administered to study dogs and all were well tolerated. Sarolaner administered orally to provide a minimum dosage of 2.0mg/kg (range 2-4mg/kg) once monthly for three consecutive treatments was safe and effective in the treatment and prevention of natural infestations of fleas and resulted in a substantial improvement of clinical signs associated with FAD.

Efficacy of sarolaner in the prevention of Borrelia burgdorferi and Anaplasma phagocytophilum transmission from infected Ixodes scapularis to dogs.

The efficacy of sarolaner (Simparica™, Zoetis) to prevent transmission primarily of Borrelia burgdorferi and secondarily of Anaplasma phagocytophilum from infected wild-caught Ixodes scapularis to dogs was evaluated in a placebo-controlled laboratory study. Twenty-four purpose-bred laboratory Beagles seronegative for B. burgdorferi and A. phagocytophilum antibodies were allocated randomly to one of three treatment groups: placebo administered orally on Days 0 and 7, or sarolaner at 2mg/kg administered orally on Day 0 (28 days prior to tick infestation) or on Day 7 (21 days prior to tick infestation). On Day 28, each dog was infested with approximately 25 female and 25 male wild caught adult I. scapularis that were determined to have prevalence of 57% for B. burgdorferi and 6.7% for A. phagocytophilum by PCR. In situ tick counts were conducted on Days 29 and 30. On Day 33, all ticks were counted and removed. Acaricidal efficacy was calculated based on the reduction of geometric mean live tick counts in the sarolaner-treated groups compared to the placebo-treated group for each tick count. Blood samples collected from each dog on Days 27, 49, 63, 77, 91 and 104 were tested for the presence of B. burgdorferi and A. phagocytophilum antibodies using the SNAP(®) 4Dx(®) Plus Test, and quantitatively assayed for B. burgdorferi antibodies using an ELISA test. Skin biopsies collected on Day 104 were tested for the presence of B. burgdorferi by bacterial culture and PCR. Geometric mean live tick counts for placebo-treated dogs were 14.8, 12.8, and 19.1 on Days 29, 30, and 33, respectively. The percent reductions in mean live tick counts at 1, 2, and 5 days after infestation were 86.3%, 100%, and 100% for the group treated with sarolaner 21 days prior to infestation, and 90.9%, 97.1%, and 100% for the group treated with sarolaner 28 days prior to infestation. Geometric mean live tick counts for both sarolaner-treated groups were significantly lower than those for the placebo group on all count days (P<0.0001). There were no adverse reactions to treatment with sarolaner. Transmission of B. burgdorferi to all eight placebo-treated dogs was confirmed by positive antibody (6 of 8 dogs), PCR (7 of 8 dogs), and/or culture (7 of 8 dogs). Similarly, transmission of A. phagocytophilum was confirmed by the presence of antibodies in four placebo-treated dogs. In contrast, treatment with a single dose of sarolaner prevented transmission of B. burgdorferi from infected ticks to dogs infested 21 or 28 days after treatment as demonstrated by negative antibody, PCR, and culture results. Prevention of transmission of A. phagocytophilum was demonstrated by negative antibody results in all sarolaner-treated dogs.