Efficacy of emodepside plus praziquantel tablets (Profender tablets for dogs) against mature and immature infections with Toxocara canis and Toxascaris leonina in dogs

First report of apparent praziquantel resistance in Dipylidium caninum in Europe

Dipylidium caninum is a common tapeworm of dogs. Two cases of praziquantel resistance have been described in D. caninum in the United States. No further reports have been published to the authors’ knowledge. Here, the case of a dog imported to Switzerland from Spain with a history of chronic excretion of tapeworm proglottids and unresponsiveness to praziquantel treatments is reported. Clinical signs were mild (restlessness, tenesmus, anal pruritus, squashy feces) and flea infestation could be ruled out. Infection with D. caninum was confirmed through morphological and genetic parasite identification. Different subsequently applied anthelmintic compounds and protocols, including epsiprantel, did not confer the desired effects. Proglottid shedding only stopped after oral mebendazole administration of 86.2 mg kg−1 body weight for 5 consecutive days. Clinical signs resolved and the dog remained coproscopically negative during a follow-up period of 10 months after the last treatment. This case represents the first reported apparent praziquantel and epsiprantel resistance in D. caninum in Europe. Treatment was extremely challenging especially due to the limited availability of efficacious alternative compounds.

Development of emodepside as a possible adulticidal treatment for human onchocerciasis-The fruit of a successful industrial-academic collaboration

Current mass drug administration (MDA) programs for the treatment of human river blindness (onchocerciasis) caused by the filarial worm Onchocerca volvulus rely on ivermectin, an anthelmintic originally developed for animal health. These treatments are primarily directed against migrating microfilariae and also suppress fecundity for several months, but fail to eliminate adult O. volvulus. Therefore, elimination programs need time frames of decades, well exceeding the life span of adult worms. The situation is worsened by decreased ivermectin efficacy after long-term therapy. To improve treatment options against onchocerciasis, a drug development candidate should ideally kill or irreversibly sterilize adult worms. Emodepside is a broad-spectrum anthelmintic used for the treatment of parasitic nematodes in cats and dogs (Profender and Procox). Our current knowledge of the pharmacology of emodepside is the result of more than 2 decades of intensive collaborative research between academia and the pharmaceutical industry. Emodepside has a novel mode of action with a broad spectrum of activity, including against extraintestinal nematode stages such as migrating larvae or macrofilariae. Therefore, emodepside is considered to be among the most promising candidates for evaluation as an adulticide treatment against onchocerciasis. Consequently, in 2014, Bayer and the Drugs for Neglected Diseases initiative (DNDi) started a collaboration to develop emodepside for the treatment of patients suffering from the disease. Macrofilaricidal activity has been demonstrated in various models, including Onchocerca ochengi in cattle, the parasite most closely related to O. volvulus. Emodepside has now successfully passed Phase I clinical trials, and a Phase II study is planned. This Bayer–DNDi partnership is an outstanding example of “One World Health,” in which experience gained in veterinary science and drug development is translated to human health and leads to improved tools to combat neglected tropical diseases (NTDs) and shorten development pathways and timelines in an otherwise neglected area.

Onchocerca volvulus is the causative agent of human river blindness, and current elimination programs rely on the use of ivermectin to kill microfilariae. Since no adulticidal drug is available and adult worms have a life span of up to 15 years, elimination programs need to be sustained over several decades. Emodepside is an anthelmintic that is licensed as a dewormer for cats and dogs. Due to its ability to eliminate nematodes located in various extraintestinal host tissues, including migrating larvae and adult filarial worms, it is considered to be an excellent candidate for the treatment of onchocerciasis. Intense collaboration between academia and the pharmaceutical industry has led to a deep understanding of the novel mode of action of the drug and of its parasite target spectrum. Phase I clinical trials with emodepside have demonstrated its safety and adulticide activity against the closely related cattle parasite Onchocerca ochengi. Currently, Phase II clinical trials are planned to confirm that emodepside, developed initially to improve animal health, has also the potential to improve human health by tackling a very important neglected tropical disease (NTD).

Zoonotic Parasitological Findings in a Puppy: The Course and Therapeutical Efficacy

Considering the close contact of companion animals and humans, gastrointestinal parasitic zoonoses are very widespread and represent a high risk of transmission with the potential of severe consequences affecting the digestive tract of both humans and other animals. In this study we focused on enteric zoonoses caused by Toxocara canis nematode, Dipylidium caninum tapeworm and Giardia duodenalis protozoa. Our primary aim was to observe Toxocara canis egg excretion within the 27 consecutive days before and after orally treatment (2 Caniverm® tablets) on Day 13 in a naturally infected puppy. An average egg per gram (EPG) of T. canis detected by coprological quantitative McMaster method was 4558.33 and 666.66, before and after treatment, respectively. The percentage of faecal egg count reduction (%FECR) in in vivo Faecal Egg Count Reduction Test (FECRT) has confirmed an 85.37 % efficacy against T. canis. Secondly, the efficacy of Caniverm® against the tapeworm Dipylidium caninum was also determined. No D. caninum proglottides were detected on Day 14. The data showed 100 % effectiveness of the anthelmintic treatment. Metrobactin® 250 mg has been tested as experimental therapy against Giardia duodenalis on Day 3. On day 10, no cysts were observed in the faeces after per os ¼ tablet administration twice a day for 7 days.

Evaluation of emodepside in laboratory models of human intestinal nematode and schistosome infections

Background

Helminthiases are very prevalent worldwide, yet their treatment and control rely on a handful of drugs. Emodepside, a marketed broad-spectrum veterinary anthelminthic with a unique mechanism of action, undergoing development for onchocerciasis is an interesting anthelmintic drug candidate. We tested the in vitro and in vivo activity of emodepside on nematode species that serve as models for human soil-transmitted helminth infection as well as on schistosomes.

Methods

In vitro viability assays were performed over a time course of 72 hours for Trichuris muris, Necator americanus, Ancylostoma ceylanicum, Heligmosomoides polygyrus, Strongyloides ratti, Schistosoma mansoni and Schistosoma haematobium. The drug effect was determined by the survival rate for the larvae and by phenotypical scores for the adult worms. Additionally, mice infected with T. muris and hamsters harboring hookworm infection (N. americanus or A. ceylanicum) were administered orally with emodepside at doses ranging from 1.25 to 75 mg/kg. Expelled worms in the feces were counted until 3 days post-drug intake and worms residing in the intestines were collected and counted after dissection.

Results

After 24 hours, emodepside was very active in vitro against both larval and adult stages of the nematodes T. muris, A. ceylanicum, N. americanus, H. polygyrus and S. ratti (IC₅₀ < 4 µM). The good in vitro activity was confirmed in vivo. Hamsters infected with the hookworms were cured when administered orally with 2.5 mg/kg of the drug. Emodepside was also highly active in vivo against T. muris (ED₅₀ = 1.2 mg/kg). Emodepside was moderately active on schistosomula in vitro (IC₅₀ < 8 µM) 24 h post-drug incubation and its activity on adult S. mansoni and S. haematobium was low (IC₅₀: 30–50 µM).

Conclusions

Emodepside is highly active against a broad range of nematode species both in vitro and in vivo. The development of emodepside for treating soil-transmitted helminth infections should be pursued.

Electronic supplementary material

The online version of this article (10.1186/s13071-019-3476-x) contains supplementary material, which is available to authorized users.

Suspected adverse reactions to oral administration of a praziquantel-pyrantel combination in captive cheetahs (Acinonyx jubatus)

OBJECTIVE To characterize adverse reactions to oral administration of a combination of praziquantel and pyrantel embonate or pyrantel pamoate, with or without oxantel embonate, in captive cheetahs (Acinonyx jubatus). DESIGN Retrospective case series and case-control study. ANIMALS 16 captive cheetahs with signs of adverse reaction to oral administration of praziquantel and pyrantel, with or without oxantel embonate (affected group), and 27 cheetahs without such reactions (unaffected group), all from 3 independent facilities. PROCEDURES Medical records and postmortem findings for affected cheetahs were reviewed and compared with those of unaffected animals. Anthelmintic doses administered, age, and sex of cheetahs were compared between groups. RESULTS 3 reactions in affected cheetahs were fatal, whereas the remainder ranged from mild to severe. Postmortem examination failed to reveal any disease processes or conditions to explain the deaths. No differences in anthelmintic dose were identified between affected and unaffected cheetahs for all facilities combined, and no correlation existed between dose and reaction severity. No association with sex was detected, but affected cheetahs were significantly younger than unaffected cheetahs. This difference was not significant after controlling for facility. CONCLUSIONS AND CLINICAL RELEVANCE Cheetahs were concluded to have had an adverse reaction to the praziquantel-pyrantel combination because of temporal proximity of onset of clinical signs to dose administration, similarity of signs to those reported for toxicosis in other species for these drugs, and a lack of other disease process or environmental explanatory factors. A highly cautious approach to the use of this drug combination is recommended for cheetahs.

Chemical Compatibility and Safety of Imidacloprid/Flumethrin Collar (Seresto®) Concomitantly Used with Imidacloprid/Moxidectin (Advocate®, Advantage® Multi) and Emodepside/Praziquantel (Profender®) Spot-on Formulations

Safety of concomitant use of veterinary products is of clinical interest. A series of studies was performed to evaluate the chemical compatibility and short term dermal and systemic safety of an imidacloprid/flumethrin collar (Seresto(®)/ Foresto(®), Bayer) used concomitantly with spot-on or tablet formulations.Chemical compatibility was evaluated in-vitro (study reference A) on collar pieces, followed by two small, non-controlled clinical studies (study reference B) in both, cats and dogs. The studies showed, that certain solvents affected the collar in-vitro, but not in their marketed formulations.Dermal and systemic safety of different spot-on or tablet formulations was first evaluated in a small, non-controlled clinical study (study reference C) in cats and dogs, via clinical observations only, followed by controlled clinical safety studies of concomitant use with imidacloprid/ moxidectin (Advocate(®)/ Advantage(®) Multi, Bayer) in dogs and cats (study reference D) and emodepside/ praziquantel (Profender(®), Bayer) in cats (study reference E), assessing safety aspects by clinical observations and statistical analyses of hematology and clinical chemistry parameters compared to baseline values and between treated and control groups.Dermal safety findings over all clinical studies (study references B to E) matched those already described for the respective products and included transient cosmetic changes (oily hair and crystal formation) at the site of spot-on application and broken hair, transient alopecia and skin alterations at the site of collar application. There were no indications of these findings aggravating under the conditions of concurrent use. There were no systemic safety findings of clinical significance in any of the clinical safety studies (study reference C to E). Assessment of blood parameters revealed some deviations from baseline levels and from the reference range in dogs as well as in cats, but no clinical relevance could be deduced. Hematology and clinical chemistry results confirmed the safety of the concomitant treatment. It is concluded that Seresto(®) is chemically compatible with solvents used in major spot-on formulations on the market and is dermally and systemically safe for adult dogs and cats when used concomitantly with Advocate(®) and Profender(®) spot-on formulations.

Pet roundworms and hookworms: a continuing need for global worming

Ascarids and ancylostomatids are the most important parasites affecting dogs and cats worldwide, in terms of diffusion and risk for animal and human health. Different misconceptions have led the general public and pet owners to minimize the importance of these intestinal worms. A low grade of interest is also registered among veterinary professions, although there is a significant merit in keeping our guard up against these parasites. This article reviews current knowledge of ascarids and ancylostomatids, with a special focus on pathogenicity, epidemiology and control methods in veterinary and human medicine.

Efficacy of emodepside plus toltrazuril (Procox(®) oral suspension for dogs) against Toxocara canis, Uncinaria stenocephala and Ancylostoma caninum in dogs

The efficacy of emodepside plus toltrazuril (Procox® oral suspension for dogs) against different species of gastrointestinal nematodes (Toxocara canis, Ancylostoma caninum, Uncinaria stenocephala) was evaluated in nine randomised,blinded and placebo-controlled laboratory studies in naturally or experimentally infected dogs. The product was used at the proposed minimum dose of 0.45 mg emodepside and 9 mg toltrazuril per kg body weight. Efficacy was calculated based on worm counts after necropsy. Worm burdens in the control dogs ranged between 0 and 409 worms of the respective stage for T. canis and between 4 and 655 worms for hookworms. The studies demonstrated 100 % efficacy of emodepside/toltrazuril suspension against mature adult, ≥ 94.7 %efficacy against immature adult and 99.3 % efficacy against the L4 larval stage of T. canis. The efficacy against mature adult A. caninum was ≥ 99.5 % and the efficacy against mature adult U. stenocephala was 100 %. All differences between treatment and control groups were statistically significant and no gender effect was found. It can be concluded that the emodepside/toltrazuril suspension represents a safe and highly effective product in dogs with nematode (T. canis, hookworms) infection.

Efficacy of Procox® oral suspension for dogs (0.1% emodepside and 2% toltrazuril) against experimental nematode (Toxocara cati and Ancylostoma tubaeforme) infections in cats

Two exploratory studies were performed to determine the optimum therapeutic dose of Procox(®) for the removal of experimental infection with mature adult Toxocara (T.) cati and Ancylostoma (A.) tubaeforme in kittens. Procox(®) is a new oral suspension containing a combination of the nematocidal and coccidiocidal active principles emodepside (0.1 %) and toltrazuril (2 %).In the first study, 18 eight-weeks-old kittens were inoculated with 450 L3 larvae of T. cati. 56 days after infection, the kittens were allocated to three treatment groups and were treated with 0.5 mg emodepside/kg body weight (group 1), 0.25 mg emodepside/kg body weight (group 2) and 0.1 mg emodepside/kg body weight (group 3), respectively. In the second study, 10 eight-weeks-old kittens were inoculated with 350 L3 larvae of A. tubaeforme. Four weeks after infection, the kittens were allocated to two treatment groups and were treated with 0.1 mg emodepside/kg body weight (group 1) or 0.25 mg emodepside/kg body weight (group 2). In both studies, all kittens received a reference treatment with Drontal(®) (230 mg pyrantel embonate and 20 mg praziquantel per tablet) at the recommended dose of one tablet/4 kg body weight 5 days after treatment with Procox(®). Anthelmintic efficacy was calculated by reduction in worm numbers expelled with the faeces following treatment with Procox(®) as compared with faecal worm numbers after reference treatment with Drontal(®), by thus avoiding necropsy of the animals.In the T. cati study, emodepside was at 99.9 %, 100 % and 96.5 % effective at a dosage of 0.5 mg, 0.25 mg and 0.1 mg per kg body weight, respectively. Against A. tubaeforme emodepside was at 95.7 % and 100 % effective at a dosage of 0.1 mg and 0.25 mg per kg body weight. No adverse events were seen during either study.It can be concluded that Procox(®) is efficacious for the control of mature adult T. cati and A. tubaeforme infections in cats at a single-dose rate of 0.25 mg emodepside/kg body weight.

Efficacy of emodepside plus praziquantel tablets (Profender tablets for dogs) against mature and immature cestode infections in dogs

The efficacy of a novel flavoured tablet formulation of emodepside plus praziquantel (Profender tablets for dogs) against intestinal cestodes was investigated in four randomised, blinded placebo-controlled dose confirmation studies in dogs experimentally infected with Echinococcus granulosus or E. multilocularis and in dogs naturally infected with Dipylidium caninum or Taenia spp. The tablets were used at the minimum recommended dose of 1 mg emodepside and 5 mg praziquantel per kg body weight. The studies demonstrated 100% efficacy against mature and immature E. granulosus and E. multilocularis and mature Taenia spp. and D. caninum. Additionally, one of the studies demonstrated non-interference of emodepside with the efficacy of praziquantel against D. caninum. No side effects of the treatment were observed. It is concluded that emodepside plus praziquantel tablets are safe and effective against mature and immature stages of E. granulosus and E. multilocularis and mature stages of Taenia spp. and D. caninum.

Efficacy of emodepside plus praziquantel tablets (Profender tablets for dogs) against mature and immature adult Ancylostoma caninum and Uncinaria stenocephala infections in dogs

This paper reports the efficacy of a novel flavoured tablet formulation of emodepside plus praziquantel (Profender tablets for dogs) against mature and immature adult hookworms (Ancylostoma caninum and Uncinaria stenocephala) in dogs. The tablets were used at the minimum recommended dose of 1 mg emodepside and 5 mg praziquantel per kg body weight. Four randomised, blinded and controlled laboratory studies demonstrated >95% efficacy against mature and immature adult stages of U. stenocephala and four randomised, blinded and controlled laboratory studies demonstrated >98% efficacy against mature and immature adult stages of A. caninum. No side effects of the treatment were observed. It is concluded that the emodepside plus praziquantel tablet is an effective and safe treatment against mature and immature hookworms.

Field evaluation of the efficacy and safety of emodepside plus praziquantel tablets (Profender tablets for dogs) against naturally acquired nematode and cestode infections in dogs

A controlled, blinded and randomised multicentre field study evaluated the efficacy and safety of a new anthelmintic tablet formulation containing emodepside plus praziquantel (Profender tablets for dogs) in the treatment of gastrointestinal nematode and cestode infections in dogs in France, Germany, Portugal and Slovakia. Dogs positive for nematodes and/or cestodes (demonstrated by faecal egg counts and/or the presence of proglottids) were treated with emodepside plus praziquantel tablets (n = 239) or the reference product containing milbemycin oxime and praziquantel (Milbemax [n = 115]) at the recommended dose rate. Two faecal samples collected between 7 and 13 days after treatment were evaluated for proglottids, nematode and cestode eggs. No suspected adverse drug reactions were observed in the study. The following parasite species were identified: Trichuris vulpis, Toxocara canis, Toxascaris leonina, Uncinaria stenocephala, Ancylostoma caninum, Dipylidium caninum, Taeniidae and Mesocestoides spp. Geometric mean nematode egg counts in dogs treated with emodepside plus praziquantel tablets were reduced by 99.9 % compared with a reduction of 99.6 % for the reference product. Statistical analysis demonstrated noninferiority of investigational versus reference product (p = 0.0342). None of the dogs treated with emodepside plus praziquantel or reference product remained positive for cestodes after treatment. The study demonstrated that emodepside plus praziquantel tablets are safe and highly efficacious against a broad spectrum of nematodes and cestodes under field conditions.

Efficacy of emodepside plus praziquantel tablets (Profender tablets for dogs) against mature and immature adult Trichuris vulpis infections in dogs

This paper reports on the efficacy of a novel flavoured tablet formulation of emodepside plus praziquantel (Profender tablets for dogs) against mature and immature adult whipworms (Trichuris vulpis) at the proposed minimum dose of 1 mg emodepside and 5 mg praziquantel per kg body weight in dogs. Three randomised, blinded and controlled laboratory studies with naturally or experimentally infected dogs were performed. The first study was conducted as a dose determination study in experimentally infected dogs using three different dose levels, i.e., 0.5x, 1x and 2x the minimum therapeutic dose. Two further studies confirmed the efficacy of emodepside plus praziquantel tablets against mature and immature adult T. vulpis at the recommended minimum dose. In all three studies, the efficacy against mature and immature adult T. vulpis was >99%. No side effects of the treatment were observed. It is concluded that the emodepside plus praziquantel tablet is an effective and safe treatment against mature and immature adult stages of T. vulpis in dogs.