AU2012200544C1

AU2012200544C1 - Anthelmintic composition

Info

Publication number: AU2012200544C1
Application number: AU2012200544A
Authority: AU
Inventors: Brian Desmond Ford; Marcus Holdsworth; Kai Kin Lau; John James O'brien; Edward Lionel Bruce Whittem
Original assignee: Jurox Pty Ltd
Current assignee: Jurox Pty Ltd
Priority date: 2003-02-05
Filing date: 2012-01-31
Publication date: 2017-06-29
Anticipated expiration: 2024-02-04
Also published as: AU2012200544B2; AU2012200544A1; AU2015200815A1; AU2012200544A2

Abstract

The invention relates to the treatment of anthelmintic infections in animals, and more particularly to compositions that are effective against parasites that are resistant to a wide variety of drug treatments. In a first aspect, the invention provides a synergistic anthelmintically effective composition consisting of at least one compound selected from each of the following groups: macrocylic lactones, benzimidazoles, salicylanilides and imidazothiazoles and a therapeutically acceptable carrier. In a second aspect, the invention provides a method for treating parasitic infections in an animal, comprising administering to the animal, a synergistic anthelmintically effective amount of a composition which consists of at least one compound selected from each of the following groups: macrocylic lactones, benzimidazoles, salicylanilides and imidazothiazoles and a therapeutically acceptable carrier. In a third aspect, the invention provides the use of a synergistic anthelmintically effective amount of a composition which consists of at least one compound selected from each of the following groups: macrocylic lactones, benzimidazoles, salicylanilides and imidazothiazoles and a therapeutically acceptable carrier in the treatment of a parasitic infection in an animal.

Description

AUSTRALIA Patents Act 1990

JUROX PTY LTD

COMPLETE SPECIFICATION STANDARD PATENT

Invention Title:

Anthelmintic composition

The following statement is a full description of this invention including the best method of performing it known to us:-

ANTHELMINTIC COMPOSITION

Field of the Invention

This invention relates to the treatment of anthelmintic infections in animals, and more particularly to compositions that are effective against parasites that are resistant to a wide variety of drug treatments, particularly in non-human animals..

Background to the Invention

Farm animals such as lambs, weaners and sheep may typically be infected by a wide variety of parasites. Such parasites include Haemonconchus spp., Ostertagia spp., Trichostrongylus spp., Cooperia spp., Nematodirus spp., Chabertia spp., Oesophagostomum spp., Trichuris spp., Strongyloides spp., Bunostomum spp.. Oestrus spp., Dictyocaulus spp., Fasciola spp. and Monezia spp. Specific examples of these parasites are set out in Table 1.

For a variety of reasons, there is an increasing number of such parasites that have developed resistance to available drug treatments. Moreover, because of the infective nature and ready transmission from animal to animal, the presence of resistant parasites will rapidly spread to infect a substantial number, if not all, of the animals in a flock or herd. One means by which such infection will rapidly spread is where new animals in which the presence of drug resistance is known or suspected are to be introduced onto a property.

There are a variety of drug substances that are used to treat parasitic infections. Amongst these broad groups of substances are macrocylic lactones, benzimidazoles, salicylanilides and imidazothiazoles. Unfortunately, many of the parasites mentioned in Table 1 have developed resistance to these substances.

Although the problem of resistance has been tackled through the development of new substances, the time to develop, evaluate and demonstrate efficacy of such substances is substantial and expensive. Moreover for the reasons that resistance has developed against existing substances it is very likely that resistance will occur in relation to these new substances.

Summary of th e |nyeii|jon

Rather than tackling the problem of resistance through the development of new substances, the present inventors have found tha|i|sfs possible to circumvent resistance by Combining speciftp;|}|sses of anthelmintic^. The out of the finding that the combination is synergistic.

According to a first aspect, there is disclosed herein an anthelminticeUv effective drench composition in the form of a micellar solution comprising: only four anthelmintic compounds wherein one anthelmintic compound is a macrocylic lactone selected from the group consisting of abamectin, ivermectin, doramectin, moxidectin and milbemycin; one anthelmintic compound is a beuztmidazoief iK la^thelimritic is closantel; and one anthelmintic compound is an imidazothiazole; a therapeutically acceptable carrier comprising water; at least one surfactant comprising polysorbaie 80; at least one dispersing agent comprising colloidal silicon dioxide; at least one phosphate buffer; and one or more wafer miscible solvent(s) selected id the group consisting of benzyl alcohol and propylene glycol, wherein the ratio of water miscible sol vent(s) to water is from about 1 · 0.75 to about 1 : 2.5 and wherein the closantel and benzimidazole are suspended in the composition. Table 1 Parasite Species

__

According to a second aspect there is disclosed»* $-- ;IPtfedd for treating- parasitic-infections in an animal, comprising administering to the ammal, an anthelmintically-effective amount, of a composition according to the first aspect*

According to a third aspect there is disclosed, use of an anthelmintically effective-amount of a composition according to the first aspect in the treatment of a parasitic infection in an animal.

Throughout this specification the word "comprise”, or variations such as "comprises'· or "comprising", will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers Or steps, but not the exclusion of any other element, integer or step, of group Of elements, integers or steps. T|| aforementioned treatments may be desirably administered to animals prior to introduction to a land area so as to prevent the land area from becoming infested with; parasites which may or may not be resistant to one or more compounds selected from the groups consisting of maerocylic lactones, benzimidazoles, saiicylanilides and imidazothiazoles. Typically* animals such as sheep, will be isolated for at least 2 days after treatment before being placed on pasture,;

Accordingly, also disclosed herein is a method according to the second aspect, wherein the drench composition is administered to the animal prior to introduction to a land area so as to prevent the land area from becoming infested, yvit'h parasites which may or may not be resistant to one or more compounds selected from the groups consisting of maefoeylic lactones, benzimidazoles, closantel and imidazothiazoles.

Alternatively, animals may be treated at any time, as appropriate, particularly when ft. is suspected that the animal may be carrying at least one parasite· which is resistant to at least one of the groups macrocylic lactones, benzimidazoles, salicylanilides and imidazothiazoles.

The compositions disclosed herein have application where the parasites ate resistant to known drug treatments, in particular, the compositions are effective in situations where parasites are resistant, to at least one of each of the groups macrocylic lactones, benzimidazoles, salicylanilides mid imidazothiazoles, Preferably, the compositions are effective in situations where parasites are resistant to at least two of each of the groups macrocylic lactones, benzimidazoles, salicylanilides and imidazothiazoles. More preferably. the compositions are efficiyein situations1 wlcrpoparasites arerfSiithhl; ϊοϊ at least three of each of the groups macrocylic lactones, benzimidazoles, salicylanilides and imidazothiazoles. Most preferably, the compositions are effective in situations where parasites are resistant to all of thes;|roupS mfterooyip lactones, benzimidazoles!, salicylanilides and imidazothiazoles.

In tipi; -preferred indication is the tflabnenii if stdilMtOydliiiihlle adult gastro- : and liver fluke. Typically, treatment reiftltsdidhesekarance of >95% bl tblll β|ή. count including worms resistant; ferit leaol; Pietβΐ! ®f the groups macrocylic lactones, benzimidazoles, salicylanilides and imidazothiazoles.

Compositions disclosed herein include one compound selected from each of die groups: macrocytic lactones, benzimidazoles, salicylanilides and imidazothiazoles. |||pkS:eni||tV;f? examples of campouftds fiiftl eachkitheSi fiiftpim sblpgffn Table 2,· I able 2 Compounds

.#f'f|esb combinations which include at: least abamectin from litei macrocylic lactone group together with one compound from each of the other three groups; at least albendazole from the benzimidazole group together with one compound from each of the other three groups; ciosantei together with one compound from each of the other three groups and levamisoie together with one compound from each of the other three groups are each preferred. Particularly preferred is the specific combination of abamectin, albendazole, ciosantei and levamisoie. Most preferably, the levamisoie is used in the form of a water soluble salt such as the hydrochloride.

The therapeutically active compounds disclosed herein are preferably incorporated into fbnnulations in the range of concentrations as follows (g/L): macroeylic lactones: 0.1-20.0 g/L, preferably 0.5-1,5 g/L benzimidazoles: 1-100 g/L, preferably 18-30 g/L.

saiieyTaniUdes: 1 -100 g/L, preferably 30-50 g/L imidazothiazoies: 1-100 g/L, preferably 30-50 g/L.

Although drenches are preferred dosage loons for the compositions disclosed herein, a number of alternative compositions may be used. These poufion transdermals, slow release boluses for rumenal deposition and injectable formulations.

Each dosage form requires a therapeutically effective carrier·, in the case of drenches, typically a formulation will include a solvent system for the macroeylic lactones, one or pore dispersing and suspending agents for the benzimidazoles and salieylanilides- , one or more surfactants, one or mrope preservatives, a buffering system and water as a carper.

The solvent system for the macrhiyelic lactones includes at least one solvent selected from the group consisting of: polyethylene glycol, tetraglycol, ethanol benzyl alcohol and propylene glycol. :T|| dispersing and suspending agents for the benzimidazoles; sand salieylanilides :pelnde; :d|l|ithM0ne: selected; ifromzthe group consisting of: glyceryl paimitdiSteliate, bentonite, colloidal silica, xanthan gum and polymeric pyrrolidones. lurfactants that may be used include polysorbale 80 and ethoxylated castor oil.

A variety of buffer systems may be used, particularly phosphate buffers based on combinations of varying amounts of monobasic and dibasic sodium phosphate; to ae|i|yg;:| hi dlstred; plT l’he compositions disclosed herein are effective when used in a variety of animals. lor example, sheep, goats, ruminants (including cattle) and cametids.

Modes for Carrying Out the invention

In order to better understand the nature of the invention, a number of examples will ;now::be::des^^

Example 4

Example 6

Example 4 was prepared as follows: 1. Dissolve abamectin in benzyl alcohol and propylene glycol. 2. Add polysorbate 80 to step 1. 3. Add water to the solution from step 2 and mix until homogeneous. 4. Dissolve sodium phosphate dibasic and sodium phosphate monobasic in the solution from step 3. 5. Add closantel, albendazole and levamisole hydrochloride. Mix until fully dispersed. a. Measure pH and, if necessary, adjust pH to 5.3 to 5.5 using base or acid as required. 6. Add Cab-O-Sil M5 to the suspension and homogenise until the thicken agent fully hydrated.

Example 5 and 6 were prepared as follows: 1. Dissolve abamectin in benzyl alcohol and propylene glycol. 2. Add the polysorbate 80 to step 1. 3. Add albendazole and closantel to step 2 and mix until full dispersed. 4. Dissolve sodium phosphate dibasic and sodium phosphate monobasic in about 480 mL of water. 5. Add the levamisole hydrochloride and Cab-O-Sil M5 to the solution from step 4. 6. Add the mixture from step 5 to the mixture in step 3 and homogenise. a. Measure pH and, if necessary, adjust pH to 5.3 to 5.5 using base or acid as required. 7. Add antifoam and make up to 1 L with water.

Based on this disclosure, the person skilled in the art would appreciate the general approach to be taken in preparing the compositions of this invention.

In order evaluate the efficacy of the compositions of the invention, a number of trials were conducted. The data obtained from the trials are equally applicable to Examples 4, 5 and 6 above.

Trial RD0201-H002: A critical pen sacrifice study evaluating the therapeutic efficacy of a combination abamectin. levamisole hydrochloride, albendazole and closantel anthelmintic formulation against resistant strains of Haemonchus contortus. Trichostrongylus colubriformis and Teladorsagia circumcincta in sheep.

This study was conducted from the 25th of February to the 29th of August, 2002, with the animal phase conducted from the 7th May to the 27(n June 2002, Suitable sheep (18) were relocated to the University of New England Animal Mouse Facility on the ?!h May 2002 iWeri weighed, identified With individually hiupl^ted ear iihtgs and treated With twice::tid Recommended dose· rate of S||epfMdrlii,Australia:^ Ply

Utd),: to remove any residual woiRniilWrdeh.:

On 22™ May 2.002: (Day -26).|&®1 ^rafirtialyiQ lihfirm individual zero faecal :e||;::eounlSr:EaWr thpf; with approximately 5000 Haemonchus conforms (maerocyclic lactone and ciosantel resistant, strains), 6000 Triehostrongylus coluhriformis (levamisole hydrochloride and albendazole resistant strains) and 5000 OsteMtagia circumcmcta (maerocyclic and albendazole resistant strains) infective larvae.

Faecal samples were collected from each sheep on 14th June 2002 (Day -3) and individual faecal egg counts were conducted. Animals were ranked on the basis of decreasing faecal egg counts and blocked into eight blocks each of two animals and randomly allocated to the treatment groups from ihese blocks. The 36 animals with the highest counts were selected for inclusion in the trial and the two animals with tire loweiilleealegg counts were· selected· as'spafeiiunimaBt

On If® Tuhi: ;20§2 (pay 0) all ittf^ ianimals were weighed, faecal sampled and animals , in Group 2 were treated as follows. Animals were weighed and dosed according to Individual livdfWeight as outlm|d|hytabie 3.

Table 3: Dosane reel me

The IS1 ffiaTsheep (iiyefaiJirig: .fbtef ii athifrials}. 'Vy<5TW sacrificed on If®' .lhnsu2002: (Day 10):(¾ collection .pf' .ileddl; isarnpldi: ΙΙοιύίβ and small intestine montents,:; Individual faecal egg counts, treatment group coprocultures and total worm counts: were conducted for calculation of treatment efficacies. ;Dri|chrites (CSIRO Research - H5rizon Technology 1996) was performed between the ;TGr: July and the 23rd August 2002 to clarity that strains of Trickostrang}>lm· cohihriformis used were: resistant to ievamisoie hydrochloride and albendazole and, Osteratagia circumcmctu were resistant to albendazole.

Faecal samples were collected according to Standard procedures and submitted to the Vpeifnaty ||dal|bi:I|esearch parasitological laboratory'. Individual strongyle faecal egg counts and group bulk coproculture for larval different! at ion were carried out, Gastrointestinal tracts were recovered according to standard procedures and following Ipiw'ashili ee iibmiftedl |p the parasitological laboratory. Individual total worm ppunts wgre :pph|ucled apderesults are summarised in the accompanying tables, 4-10 and 'figures iMh: o* .· —

Table 4; ©roup mean strongyle faecal egg counts;,

1 Means with different superscripts within the same column are significantly different at pO.OS

Table 5: Percentage reduction of strongyle species (based on group- mean: strongyle faecal egg count data):

Table 6: Group mean abomasal Total Worm Counts

Note: Example 4 = abamectin / closantel /albendazole /levamisole hydrochloride a Haemonchus species; b Ostertagia species; d imm = immature; c L4 = fourth larval stage 1 Means with different superscripts within the same column are significantly different at p<0.05

Table 7: Percentage reduction of abomasal worms (based on Total Worm Counts)

a Haemonchus species; D Ostertagia species; α imm = immature;c L4 = fourth larval stage Table 8: Group mean small intestinal Total Worm Counts

“Trichostrongyle species; cNematodirus species; d imm = immature; 'Cooperia species 1 Means with different superscripts within the same column are significantly different at p<0.05

Table 9: Percentage reduction of small intestinal worms (based on Total Worm Counts)

a Trichostrongyle species; d imm = immature;

Table 10: Larval differentiation results following group bulk coproculture- Larvae as a % of the total number counted.

Conclusion: Excellent control (>99.9% reduction) of a mixed gastrointestinal strongyle burden as assessed by geometric faecal egg counts was achieved by the use of the Example 4 formulation at the conclusion of the trial (Day 10),.

Excellent control (>99.9% reduction) was achieved by the Example 4 formulation against the major nematodes, macrocyclic lactone and closantel resistant strains of Haemonchus spp. (adult and immature stages - geometric means), macrocyclic and albendazole resistant strains Ostertagia spp. (adult, immature and L4 stages - geometric means) and levamisole hydrochloride and albendazole resistant strains of Trichostrongylus spp (adult and immature stages - geometric means) as assessed by geometric total worm counts.

Trial JUA1240r: A property faecal egg count reduction study evaluating the therapeutic efficacy of the Example 4 formulation against field strains of mixed nematode population of either Haemonchus contortus. Trichostrongylus colubriformis and/or Teladorsaeia circumcincta in sheep.

This study was conducted from the 16th May 2002 to the 20th August 2002 with the animal phasel conducted between the 1st July 2002 to the 17th July 2002 and animal phase 2 between 5th September 2002 to the 4th October 2002. A trial site was sought, containing a mob of Merino sheep that were known to be harbouring resistant strains of nematodes (including either closantel resistant and/or macrocyclic lactone resistant Haemonchus species, as well as either benzimidazole resistant and/or levamisole resistant Trichostrongylus colubriformis and/or Teladorsagia circumcincta.) Pre-trial monitoring of the site confirmed that the intended trial animals carried a nematode burden of greater than 400 eggs/gram. A group coproculture was performed on these prospective trial sheep to establish the genera present.

On Day -3 of the trial, a mob of approximately 300 Merino ewes was mustered into a set of sheep yards. Eighty ewes were identified with uniquely numbered eartags and faecal sampled as they presented in the race. The faecal samples were returned to Veterinary Health Research for individual faecal egg counts and a bulk coproculture.

The sixty animals with the highest strongyle faecal egg counts, as determined by the Day -3 faecal egg counts, were selected for inclusion in the trial. These sheep were allocated to one (1) of six (6) treatment groups, on the basis of their faecal egg counts, such that each group had a similar arithmetic group mean faecal egg count.

On Day 0 (treatment day), each animal was weighed and treated according to the treatment schedule outlined in Table 11. Clinical observations were conducted one hour post-treatment to determine whether any adverse reactions had occurred in relation to treatments. None were detected.

Table 11: Treatment table (phase 1)

The trial concluded on Day 13 when faecal samples were collected and returned to the Veterinary Health Research Laboratory for individual faecal egg counts and group coprocultures. The entire mob was administered an effective broad-spectrum anthelmintic to remove any existing worm burden.

The aim of this field study was to study and evaluate under field conditions, the i therapeutic efficacy of Example 4 when administered to sheep that are known to be harbouring resistant strains of nematodes. The selected trial site was known to harbour closantel resistant Haemonchus contortus. This however was not confirmed during the initial phase of the study as a full dose of closantel was administered (as stated in the protocol). Standard industry practice for diagnosis of closantel resistance in the field involves either the administration of a full dose of closantel and sequential sampling of treated sheep over three to six weeks post treatment, or alternatively administration of a 1/3 dose and sampling at 10 to 14 days post treatment. A second faecal egg count reduction study was conducted after consultation with the Study Sponsor to confirm the closantel resistance status at the trial site, “Kelvin East”. The second phase of the study involved two groups of sheep each consisting of ten animals. Ten random faecal samples were collected prior to treatment from the mob of wethers to confirm a nematode burden of greater than 400 eggs/gram, and a group coproculture that confirmed a very high percentage (91%) of Haemonchus contortus were present. On Treatment Day (Day 0), individual faecal samples were collected from twenty animals as they presented in the race. These animals were weighed and weights recorded and treatments administered in accordance to the treatment regime (detailed in Table 12). Faecal samples were returned to Veterinary Health Research for individual faecal egg counts and group coprocultures. Animals were observed post treatment for adverse reactions. None were detected.

Table 12: Treatment table (phase 2)

The second phase of this trial concluded on Day 11, with the collection of individual faecal samples from all animals. These samples were returned to Veterinary Health Research for individual faecal egg counts and group coprocultures. > Faecal samples for phase 1 were collected during pre trial monitoring, (Day -3), at treatment (Day 0) and at the conclusion of the trial (Day 13) and for phase 2 at treatment (Day 0) and at the conclusion of the trial (Day 11). Results from faecal egg counts, larval differentiation and calculated treatment efficacies are summarised in the accompanying tables 13-24 and figures 5 and 6. Note that in figures 5 and 6, "Jurox" ) refers to example 4.

Table 13: Pre trial monitoring results.

Table 14: Group arithmetic mean faecal egg counts and body weights at Day 0.

1 Means in the same column with different superscripts are significantly different at p<0.05

Table 15: Group arithmetic and geometric mean faecal egg counts (epg).

Table 16: Overall percentage efficacy calculated using arithmetic and geometric group mean faecal egg counts.

Tahle 1 7· Pereentapes of nematode tvnes nresent nre-trial Dav 0 and Dav 1 7,

Haem - Haemonchus, Trich - Trichostrongylus, Tel - Teladorsagia, Coop - Cooperia, Oes - Oesophagostomum Table 18: Efficacies calculated for each nematode genus.__

Haem - Haemonchus, Trich - Trichostrongylus, Tel - Teladorsagia, Coop - Cooperia, Oes - Oesophagostomum na - not assessed

Phase 2

Table 19: Treatment day monitoring results.

Table 20: Group arithmetic mean faecal egg counts and body weights at Day 0.

Table 21: Group arithmetic and geometric mean faecal egg counts.

Table 22: Overall percentage efficacy (arithmetic and geometric means)

Table 23: Nematode population % - Pre-trial, Day 0 and Day 11 (based on faecal culture and larval differentiation).

Haem - Haemonchus, Trich - Trichostrongylus, Tel - Teladorsagia, Coop - Cooperia, Oes - Oesophagostomum Table 24: Individual nematode efficacies.

Haem - Haemonchus, Trich - Trichostrongylus, Tel - Teladorsagia, Coop - Cooperia, Oes - Oesophagostomum na - not assessed -ve - negative

Conclusion: The second faecal egg count reduction test was to confirm the presence closantel resistant Haemonckus at the trial site. This was achieved by administering a one third dose of closantel to a group of ten (10) animals and the addition of another group of ten (10) animals retained as untreated controls. The use of a one third dose of closantel is standard industry practice for diagnosis of closantel resistance in the field. Reduced efficacy of closantel was observed against Haemonckus, confirming. The presence of closantel resistant Haemonckus at the trial site.

The inclusion of the levamisole and benzimidazole groups confirmed the resistance status of Trichostrongylus.

Excellent efficacy (> 99.0%) was attained by the Example 4 formulation against a mixed gastrointestinal population including closantel resistant Haemonckus as well as levamisole and benzimidazole resistant Trichostrongylus. z/

Trial JUA1273r: A property faecal egg count reduction study evaluating the therapeutic efficacy of the Example 4 formulation against field strains of mixed nematode populations, including closantel resistant strains of Haemonchus contortus in sheep. 5 This study was conducted from the 5th of September 2002 to the 23rd of October 2002, with the animal phase conducted between 10th of September 2002 and the 1st of October 2002. Routine monitoring of a trial site known to harbour closantel resistant strains of Haemonchus contortus was conducted to identify a suitably infected group of sheep. Pre-trial monitoring confirmed that one group of sheep (270 Merino hoggets) 10 was suitably infected with a high burden of Haemonchus contortus.

On Day -2 of the trial individual faecal samples were collected from ninety (90) potential trial sheep and individual strongyle faecal egg counts performed. Trial sheep had already been identified Using uniquely numbered ear tags as part of standard 15 farming practice at the trial site. From the ninety (90) potential trial sheep sixty (60) sheep were selected and allocated (according to individual strongyle faecal egg counts) to six (6) groups of ten (10) sheep each, such that each group had a similar group arithmetic mean strongyle faecal egg count and range of faecal egg counts within the group. 20

On Day 0 of the trial (18th September 2002) selected trial sheep were weighed (see figure 7 for arithmetic mean body weights and note that the treatment "Jurox" refers to the treatment with Example 4), the weights recorded and individual faecal samples collected for individual strongyle faecal egg counts. Trial sheep in Group 2 were 25 treated according to individual body weight with the test formulation, trial sheep in Groups 3-6 were treated with the respective reference formulation and trial sheep in Group 1 were retained untreated as negative controls. Groups 2, 3, 5 and 6 were treated at the recommended dose rate for each active, while sheep in Group 4 were treated at one third the normal closantel dose rate, to determine and demonstrate the presence of 30 closantel resistance (Reference: Rolfe PF; Fourth International Confess for Sheep Veterinarians 1997, pg 55). Sheep were observed in the immediate post-treatment period for adverse reactions (none were observed). Individual strongyle faecal egg counts and group bulk coprocultures for larval differentiation were subsequently performed on the samples collected. 28

Trial sheep were returned to the sheep yards on Day 13 of the trial (1st October 2002) and individual faecal samples again collected. All trial sheep received a single therapeutic dose of Rycozole®1 due to animal welfare concerns. Individual strongyle faecal egg counts and group bulk coprocultures for larval differentiation were 5 subsequently performed on the samples collected.

Treatment efficacies were then calculated using group arithmetic and geometric strongyle faecal egg counts for the major strongyle species present (see figures 8 and 9 and note that the treatment" Jurox" refers to treatment with Example 4). 1 Rycozole Oral Anthelmintic for Sheep and Cattle, Novartis Animal Health Australasia Pty Ltd

Table 25: Treatment table.

Table 26: Group arithmetic mean, maximum and minimum strongyle faecal egg counts and standard deviations following allocation.

Table 27: Treatment details. _

^„ 1 Means within the same column with the same superscript are not significantly different at p<0.05

Faecal samples were collected during pre trial monitoring, on Day -2 for allocation purposes, at treatment (Day 0) and at the conclusion of the trial (Day 13). Results from faecal egg counts, larval differentiation and calculated treatment efficacies are summarised in the accompanying tables.

Tahle "?8· Pre trial mnnifnrina results

Table 29: Group Arithmetic and Geometric Mean strongyle faecal egg counts during the trial (excluding Nematodirus spp.)

1,2,3 Means within the same column with the same superscript are not significantly different at p<0.05

Table 30: Larval differentiation results from group bulk coprocultures.

a Haemonchus spp., bTrichostrongylus spp., cCooperia spp., dOesophagostomum spp.

Table 31: Overall treatment efficacies, against all strongyle species (apart from Nematodirus spp.)

Table 32: Treatment efficacies against Haemonchus contortus._

Conclusion: Excellent efficacy (greater than 99.9% based on group arithmetic and geometric means and larval differentiation results) was attained by the Example 4 formulation against a gastrointestinal strongyle population consisting almost exclusively of Haemonchus contortus.

Efficacies attained by the comparison formulations against this strain of Haemonchus contortus ranged from 85.5% for the albendazole formulation (Valbazen®) through 96.1% for the ivermectin formulation (Ivomec®) to 99.8% for the levamisole formulation (Levamisole®), based on group arithmetic mean faecal egg counts and larval differentiation. Efficacies attained against this strain based on geometric mean faecal egg counts and larval differentiation were 84.9%, 97.5% and >99.9% for these formulations respectively. These results indicate that this strain is moderately resistant to white drenches (benzimidazoles) and fully susceptible to levamisoles, with a slight but non-significant reduction in efficacy for ivermectin. Ivermectin was 96.1% (arithmetic) and 97.5% (geometric) efficacious, which establishes that this strain could not be defined as macrocyclic lactone resistant at present.

Treatment with a 1/3 dose of closantel resulted in a treatment efficacy of 83.0% based on arithmetic group mean faecal egg counts and a treatment efficacy of 86.8% based on geometric group mean faecal egg counts, confirming the presence of moderate closantel resistance by this Haemonchus strain. Insufficient numbers of other gastrointestinal strongyles (Nematodirus, Teolodorsagia and Trichostrongylus species) were present to draw any conclusions about efficacy of the test formulation against these strains. 35

Trial JUA1270r: A property faecal egg count reduction study evaluating the therapeutic efficacy of the Example 4 formulation against field strains of mixed nematode populations, including macrocvclic lactone resistant strains of Haemonchus contortus in sheep in sheep.

This study was conducted from the 5th of September 2002 to the 7th of November 2002, with the animal phase conducted between 11th and 25th of October 2002. Routine monitoring of a trial site known to harbour macrocyclic lactone resistant strains of Haemonchus contortus was conducted to identify a suitably infected group of sheep. Pre-trial monitoring confirmed that one group of sheep (approximately 200 Merino wether hoggets) was suitably infected with a high burden of Haemonchus contortus.

On Day 0 of the trial, ninety six (96) sheep were randomly selected from a larger mob as they appeared in the sheep handling facility, weighed (see figure 10 for arithmetic mean body weights and note that the treatment "Jurox" refers to treatment with example 4) and individual faecal samples collected for subsequent individual strongyle faecal egg counts and group bulk coprocultures. Sheep had been previously allocated to six (6) treatment groups, one (1) of eleven (11) sheep to act as untreated (negative) controls and five (5) groups of seventeen (17) sheep, to be treated with the test formulation and a range of registered reference formulations. Trial sheep in Group 1 were retained untreated, while sheep in Groups 2-6 were treated according to individual body weight with the test and reference formulations. Sheep were observed in the immediate post-treatment period for adverse reactions (none were observed). Trial sheep were then returned to their parent flock and maintained in open grazing paddocks.

On Day 13 of the trial sheep were returned to the sheep handling facilities. Individual faecal samples were collected from trial sheep and individual strongyle faecal egg counts and group bulk coprocultures for larval differentiation were subsequently performed on the samples collected.

Treatment efficacies were then calculated using group arithmetic and geometric strongyle faecal egg counts for the major strongyle species present (see figures 11 and 12 and note that the treatment "Jurox" refers to treatment with Example 4).

Table 33: Treatment table.

Table 34: Group arithmetic mean, maximum and minimum strongyle faecal egg counts and standard deviations following allocation.

Table 35: Treatment details.__,

1 Means within the same column with the same superscript are not significantly different at p<0.05 Table 36: Pre trial monitoring results

Table 37: Group Arithmetic and Geometric Mean strongyle faecal egg counts during the trial.

Table 18: Larval differentiation results from group bulk coprocultures.

aHaemonchus spp., bTrichostrongylus spp., cCooperia spp., dOesophagostomum spp.

Table 39: Treatment efficacies against Haemonchus contortus.

Conclusion: Efficacies attained by the formulations against this strain of Haemonchus contortus for the ivermectin formulation (Ivomec®), the albendazole formulation (Valbazen®), the closantel formulation (full dose Sustain®), the levamisole formulation (Levamisole Gold®) and for the test formulation, based on group geometric mean faecal egg counts and larval differentiation were negative, 3.0%, 65.3%, 78.9% and >95% respectively.

While moderate efficacies were attained by the reference closantel formulation, a full (label) dose rate of this formulation was used in this case. In instances of moderate closantel resistance efficacies are still usually >95% for a full dose, with a reduction in initial efficacy only evident at a 1/3 normal dose rate. This particular strain is therefore severely resistant to closantel. These results indicate that this strain also has severe resistance to white drenches (benzimidazoles) and macrocyclic lactones and moderate resistance to levamisole. This strain of Haemonchus contortus is, therefore, moderately to severely resistant to all four drug families. Unexpectedly, the Example 4 formulation containing an example of all four of these families resulted in effective treatment of the infestation.

It will be appreciated by persons skilled in the art that numerous variations and/or modifications may be made to the invention as shown in the specific embodiments without departing from the spirit or scope of the invention as broadly described. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive.

Any discussion of documents, acts, materials, devices, articles or the like which has been included in the present specification is not to be taken as an admission that any or all of these matters form part of the prior art base or were common general knowledge in the field relevant to the present invention as it existed before the priority date of each claim of this application.

Claims

CLAIMS:»

1. An anthelmintically effective drench composition in the form of a micellar solution, comprising: only four anthelmintic compounds wherein one anthelmintic compound is a macrocylic lactone selected. froin the group consisting: of abameetm, ivermectin, doramectin, rnoxidectin and milbemycin; one: anthelmintic compound is a benzimidazole; one:: ahthelmindc::is closantd; tfodfone anihelih|i|deomppuhd is an irnidazoihiazole; a therapeutically acceptable carrier comprising water; Uf least one spltadtani comprising pbiySorbafe: 80; at least one dispersing agent comprising colloidal silicon dioxide; at least one phosphate buiforjsand one or more water miscible solvent(s) selected from the group consisting; of benzyl alcohol and propylene glycol, wherein the ratio of water miscible solvents} to water is from about 1 : 0.75 to about Tf 2,5 and wherein the closantd and benzimidazole are suspended in the composition:. 2. fhe composition of claim l wherein the benzimidazole is selected from the group consisting of albendazole, ienbendazoie, thiabendazole, oxfenbendazole, fenbamel, mebendazole, parbendazole, flubendazole, oxibendazole and carbendazoie,
3. The composition of claim 1 or 2 wherein the imidazothiazole is selected from the group consisting of Ievamisole, pyrantel pamoate and butamisole.
4. The composition of any one of claims 1 to 3; therein the four anthelmintic compounds consist of abamectin, albendazole, eiosante! and ievamisole.
5. The composition of claim 4 wherein the: Ievamisole is in the form of a hydrochloride salt.
6. The composition of any one of claims 1 to 5 wherein the compisitiou: ebmprlsca: tflfcrocyelie lactone: compounds iiiatl amoUht of ffim 0.1-20.1;g|L; bdhzirntdazote compounds in an amount, of from l»l00g/L; elosantel compounds in an amouhf of from: $M 00 g^; and imidazoiliiazole compounds in an amount, of from 1-100 g/L,
7. The composition· of any one of claims 1 ία 6 wherein the composition comprises: macrocyclic lactone-compounds-in an amount of from 0,5-1.5 g/L; benzimidazole compounds in an amount of from 18*30 g/L; closantel compounds in an amount of from 30-50 g ' f..; and imidazothi azoic compounds in an amount of from 30-50 g/L. 8. ||tf comppltipp pfe&py bne hfebi|ims 1 ;|y: Ψ whifein the phosphate buffer includes monobasic and dibasic sodium phosphate. I, The composition according to claim 8 wherein the ratio of monobasic to dibasic sodium phosphate is 9 : 1,
10. The composition according to claim 10 wherein the monobasic sodium phosphate is in an amount, of from about 9 g/L to about 18 g/L, II, The composition according to any one of claims 1 to 1.0 wherein the composition comprises polysorbate 80 in an amount of from about 150 g/I, to about 200 g/L.
12. The composition according to any one of claims 1 to 11 wherein the composition comprises colloidal silicon dioxide in an amount of from about 18:0 g/L to about 20.0 g/L.
13. The composition according to any one of claims 1 to 2 wherein the composition comprises benzyl alcohol in an amount of 80 g/L and propylene glycol in an amount of 300 g/L. 14 The composition according to any one of claims 1 to 13 wherein the composition comprises benzyl alcohol in an amount of 30 g/L. and propylene glycol in afeathount of 200 g/L..,
15. The composition of any one of claims 1 to 15 wherein the maerdeyclie lactone selected is from the group consisting of abamectin, ivefmeetin, doramectin and milbemycin. 'fiie composition of any one of claims 1 to: 15 wherein the four anthelmintic compounds consist of abamectm, albendazole, ciosantei and levamisole.
17. The composition of any one of claims Tyl6 therein: the composition is a synergistic aiithclmintically effective composition.
18. A method of treating parasitic infections in an animal comprising administering to the animal, an antbelmintically effective amount of a composition according to any one of claims 1-17,
19. The method of claim 18 wherein the method is a method of treating infection in an animal hyraf jeasf :phe species of parasite selected fTcitid::: groffp: stipg: of M&emonchuS: pon0PBu$.}. fflaemornkus place!. fitiwldgip eimumeimm, Trichosirangyhts axei. Trie ho,si rang) 'lus cohthnformis, Tricho,strong} >lus vitrinm, Cooperia curticel, Cooperia oncophera, Nematodlms spaihiger Nematodirus filicollis, Chabertia <mna, Oesophagostomum caltmhumvm, Oesophagostomum vemtlmum, Trickuris avis, Strangyloidex papilhsus, Bunoslomwn spp, Oestrus evix, Diciyocaulus viviparus, Fasciola hepatica. and Monezia.
20. The method of claim 18 or 19 wherein the method is a method of treating; infection in an animal fy parasites resistant to at least one of each of the: groups macrocvlic lactones, benzimidazoles, ciosantei and imidazothiazoles,
21. The method of claim 18 or 19 wherein the method is a method of treating infection in an animal by parasites resistant to at Hist: two of each: of the gfo«ps: maerocylic lactones, benzimidazoles, ciosantei and imidazothiazoles.
22. The method of claim 18 or 19 wherein the method is a method of treating infection in an animal by parasites resistant to at least three of each of the groups macrocyiic lactones, benzimidazoles, ciosantei and imidazothiazoles. Thl; p|||ld of lliilis 18 or 19 %ihai?ein tiie methodTs a Methodlcf· fretting: ,ίϊΐΐι: :ϊί^: papsites resillpifitp alimf The gmuparmacro^|o::|^ti3aeSr benzinuda:pies>: closantel and imida/.othiazoies. 24 The method of claim 18 or 19 wherein the method is a method of treating infection in an animal by gaslro-inieslinal worms and liver fluke.
25. The method of any one of claims 18 to 24 liheiiin the composition is administered to the animal prior to introduction to a land area so as to prevent the land area from becoming infested with parasites which may or may not be resistant to one or ;more cotipb«n4li :#<decfe<§ flop, the groups consisting:: of" paerdeyie lactoneiS, benzimidazoles, di0§ahtefM^ 26:,: The methol of claim 25 Wherein the animal ip Isolated for at least; lidaysiaSer treatment prior to introduction to the land area.
27. The use of an anihelminticallv effective amount: of a composition according to any one of claims 1-16 in the treatment of a parasitic infection in an animal. 28 f he method of any one of claims 18 to 26 or the use of claim 27 to wherein the animal is selected from the group consisting of sheep, goats, ruminants and camelids.