CaniLeish The first vaccine in Europe against leishmaniosis

Transcription

1 LEISHMA NEWS CaniLeish The first vaccine in Europe against leishmaniosis Photo: Frédéric Decante

2 Deadly disease affecting travelling dogs Introduction Those of you having travelled to southern Europe, parts of Asia and Central & South America or who have spoken to pet owners travelling with dogs to these regions will no doubt be highly aware of the risk of contracting leishmaniosis via the bite of an infected sandfl y. This parasitic disease currently infects an estimated 2.5 million dogs in south-western Europe alone and the disease is now spreading northwards 1-3. With the increase of pet travel to these regions and the routine import of dogs for breeding purposes, the need to develop ways of improving the prevention of this disease have become essential. Dogs are the principle reservoir for this Zoonotic disease (known as Leishmaniasis in humans) in Europe, a disease which causes both a serious veterinary problem and an increasing effect on public health. Indeed, secondary to Malaria, leishmaniasis is the biggest parasitic cause of human fatality in the world 4. Canine leishmaniosis in Europe (Pr. P. BOURDEAU Original) (Courtesy Prof P. Bourdeau) shows the current broad epidemiological situation in Europe. Strongly enzootic Enzootic Zone of enzootic extension Potential for extension due to presence of the vector Countries/zones where autochthonous cases have been described (non-enzootic) Imported cases Poorly documented situations: Autochthonous cases Enzootic Imported cases *The boundaries of the zones are not given precisely *The map is derived from work on European studies and congresses (Bourdeau: EMOP 2004; WorldLeish4 2009; ECVD 2009; RESFIZ 2009) Cyprus

3 The Parasite Leishmaniosis is a vector-borne parasitic disease caused by the protozoal parasite of the genus Leishmania (L.infatum in the Mediterranean basin). The life-cycle comprises of the transmission of a promastigote (motile lifestage) parasite from a sandfl y to the host (dog or human). The promastigote is taken up by a host macrophage within which it transforms into an amastigote (intracelleluar, non-motile lifestage), multiplies, bursts from the cell and infects other cells. Following a blood meal from an infected animal the amistigotes are taken up by the sandfl y within which they transform into promastigotes. Life cycle of L. Infantum (adapted from Roze, 2005) 5 Multiplication SANDFLY Transformation into promastigotes Promastigotes BLOOD MEAL HOST SKIN Uptake by macrophage HOST Infect other cells Internal organs Amastigote multiplication Amastigotes release Why has leishmaniosis been difficult to prevent Traditional prevention of leishmaniosis has relied upon methods of controlling the sandfl y vector (habitat modifi cation, repellents (collars, sprays and spot-ons) and lifestyle management). Even during correct use, none of these topical products are able to completely prevent all sandfly bites 6. In some areas of the world, such as Brazil, a strategy of compulsory euthanasia of infected dogs has been tried for public health reasons. Treatment of leishmaniosis is not only expensive but does not provide a cure.

4 Outcomes of parasitic exposure The individual reaction to the parasite from dog to dog differs, depending upon whether the parasite is cleared, remains subclinical or causes clinical disease that can lead to death. The outcomes of parasite exposure in the dog Naïve dog in endemic region Parasite free (not exposed) Exposed to parasite Parasite continues to multiply in the body Parasite remains silent for a time (subpatent dog) Parasite is controlled and eliminated from the body Asymptomatic active infection Symptomatic active infection Long term asymptomatic active infection Cured and parasite free Chronic infection (fatal) It can take years for the clinical signs which would instigate a visit to the vet to develop, during this time the dog is a reservoir for infection of both other dogs and humans. Clinical signs include: Fever, hair loss (particularly around the eyes),weight loss. Dermatitis and nail problems. Problems with internal organs which can lead to arthritis, anaemia and kidney failure. Why does this happen The infection outcome differs depending upon the orientation of the immune response of the individual dog 7,8. In the case of leishmaniosis the macrophages are not only the antigen presenting cells but also the cells which host the parasite. In simple terms (in reality it is much more complicated) the macrophages of the infected dog are either stimulated to kill the intracellular parasite within it or to support its growth and therefore lead to infection.

5 The immune response to Leishmania The immune response differs depending upon which arm of the T helper cell pathway is selected and the cytokines these pathways release affect the way in which the macrophage deals with the parasite 9. TH1 pathway stimulates cell-mediated immunity TH2 pathway stimulates humoral immunity Both produce memory cells. Whilst the reponse of the animal will induce both pathways: Resistance to canine leishmaniosis is associated with a strong TH1 cell mediated response 7,8 A key deciding step in the outcome of infection appears to be the ability of the lymphocytes to respond to antigen presentation by producing IFN-γ, a prominent Th1 cytokine 10. The impact of Th1 and Th2 cytokines on the macrophage metabolism of L-arginine and the resulting impact on parasite control Th2 cytokines e.g. IL-10 Arginase Polyamides Key parasite nutrients Macrophage L- Arginine inos Nitric Oxide Th1 cytokines e.g. IFN-γ Progression to disease is associated with a predominance of TH2 cytokines and a marked humoral response in the absence of a strong TH1 response 11. Parasite growth Parasite death The challenge to develop a vaccine Whilst vaccination is the most effective way of preventing many diseases, advancement in relation to leishmaniosis has been hindered by this unpredictable immune response. Vaccination would be of no advantage using the traditional method of presenting antigens alone as the TH2 pathway would still be stimulated in those dogs in which this pathway is taken under natural infection. The only way to effectively vaccinate an animal against leishmaniosis would be not only to present relevant antigenic material but also to somehow drive the immunogenic response down the TH1 pathway. The implication of such vaccine technology has exciting potential in both human and animal medicine. If vaccination were possible its use would be encouraged in ALL dogs travelling to infected regions to prevent both clinical disease and the continued spread into non-endemic regions. However despite significant investment, no suitable vaccine has been available in Europe......that is until now!

6 The first vaccine against canine leishmaniosis in Europe, is the result of cutting-edge research and 20 years of collaboration by high-level scientists 12 A patented and revolutionary cellfree and serum-free culture medium was designed to provide the conditions required to grow the complete life cycle of Leishmania parasites, without the use of experimental animals, like dogs. Serum-free cell-free culture Parasites All proteins in this unique growth media are produced (excreted or secreted) by the parasite L. infantum. These proteins are called ESP = Excreted Secreted Proteins PURE ESP

7 A new vaccine that stimulates an appropriate cellular immune response specific to the parasite L. infantum In contrast to many conventional vaccines, effective protection against canine leishmaniosis requires a cellular and not a humoral (antibody) immune response. This new vaccine against canine leishmaniosis induces a solid specifi c, cell-mediated (cellular) immunity towards this intracellular pathogen. Active ingredients of CaniLeish ESP are proteins excreted and secreted by the parasite during a culture process. ESP These proteins are highly immunogenic for an appropriate immune response against L. infantum. ESP are better stimulators of T-cell proliferation than a whole parasite protein extract 14. QA-21 QA-21 adjuvant is a purified saponin component of Quil-A. It possesses the rare ability to stimulate the Th1 response and production of cytotoxic T lymphocytes. Therefore, it is ideal for use in a vaccine directed against intracellular pathogens. QA-21 has a very good general safety profi le, as demonstrated by Leucogen (vaccine against feline leukaemia). ESP A strong stimulator of the desired immune reaction. QA-21 The perfect synergistic adjuvant to optimise the cellular immune response. CaniLeish

8 Proven efficacy Experimental challenge trial The ability of CaniLeish to stimulate cellular immunity has been demonstrated through several immunologic assays during a controlled experimental challenge trial. Experimental conditions Two groups of dogs: CaniLeish vaccinated and non-vaccinated. Three doses given at three-week intervals. Dogs challenged by intravenous injection of highly virulent L. infantum promastigotes, one year after completion of the initial vaccination schedule. Results IFN-γ production demonstrated: One year duration of immunity. One year after the primary course, the CaniLeish group was still signifi cantly better than the control group at responding to the challenge, with the desirable Th1 response. Spots per 2x5 10 cells ELISpot IFN-γ production (with standard error of the mean) Vaccinated mean Control mean Week Primary vaccine course weeks 0, 3, 6 IV challenge week 58 The leishmanicidal response in the dogs macrophages showed that: Soon after the primary course, the protective mechanisms were functioning well. This protection was maintained for a full year, which correlates well with the IFN-γ data. When CaniLeish vaccinated dogs were exposed to the parasite, this response remained high and effective, compared with that observed in the control group. Canine macrophage leishmanicidal assay (with standard error of the mean) CMLA Index Vaccinated mean Threshold Control mean Primary vaccine course weeks 0, 3, 6 Week IV challenge week 58 LEISHMANIOSIS NEWS 2011 / NUMBER 1 / UK EDITION

9 Challenge under extreme field conditions Extreme condition field trial How were the conditions extreme Highly endemic area. Dogs continuously housed outside for two years. No sandfl y repellent treatments during the entire trial. The natural challenge was so high that 23.1% of the control dogs developed symptomatic leishmaniosis within two years. p-value: Non vaccinated dogs % Results from the vaccinated group demonstrated the clear benefit of CaniLeish. In these extreme conditions, rarely, if ever, encountered in reality, 92.7% of the dogs in the CaniLeish group did not develop symptomatic leishmaniosis. Vaccinated dogs % 92.7% of dogs in the CaniLeish group did not develop symptomatic leishmaniosis. p-value: CaniLeish... the first vaccine available in Europe against canine leishmaniosis. the only effective measure that specifically stimulates an appropriate cellular immune response to the parasite L. infantum. a proven high level of efficacy under extreme field conditions. takes you to a new level of protection against canine leishmaniosis.

10 Proven safety ESP as the active ingredient of CaniLeish has an important positive influence on the safety of the vaccine. The innovative ESP-technology ensures that CaniLeish contains: Only parasite-derived proteins. No whole parasites and therefore no risk of return to virulence in any host. Only a specific subset of parasite proteins and not the whole parasite protein extract. Two types of safety studies have been conducted: laboratory testing and field trials. Laboratory testing Design Dogs aged four months old (i.e. younger than the recommended age of six months). Higher dose of antigens. No massaging of the injection sites. Extra dose or overdose depending on the trial. Results Administration of four doses was well tolerated - the only signifi cant fi ndings were mild, transient, local swelling. Injection of a double dose was well tolerated - again, the only signifi cant fi ndings were mild, transient, local swelling, with occasional transient hyperthermia. Two field trials Design 382 client-owned animals. Dogs aged four months to 12 years old. In endemic and non-endemic areas. All breeds were eligible for inclusion. Results The results of the various safety studies confi rmed a good safety profi le for CaniLeish. The reaction rate reported by owners under the field conditions was slightly higher than would normally be expected for a standard viral or bacterial vaccine such as DHP(Pi)L. Although the vaccine is not licensed for use in Leishmania-positive dogs, the safety of CaniLeish is as good in these dogs as in the rest of the population.

11 How to use the vaccine Use of a rapid serological diagnostic test is recommended prior to vaccination in animals who have previously been at risk of exposure to the Leishmania parasite. If this test is negative, you can start the vaccination course. Primary vaccination course: three subcutaneous doses. First dose can be administered from six months of age. Second and third doses are administered at three-week intervals. Then, only one re-vaccination per year is necessary. Puppy vaccination * Annual Booster Annual Booster Birth Age: DHP(Pi)L 3 months CaniLeish 6 months DHP(Pi)L CaniLeish DHP(Pi)L CaniLeish 3 inj. over 6 weeks Adult dog vaccination * (starting after an annual DHP(Pi)L booster) Annual Booster Annual Booster DHP(Pi)L CaniLeish DHP(Pi)L CaniLeish DHP(Pi)L CaniLeish Practical tips: Bring the vaccine close to body temperature by warming it in the hand. Massage the injection site lightly after administration. * Separate the time of vaccination with CaniLeish from all other vaccines by at least two weeks. For more information about CaniLeish : Ask your virbac representative or call head office on Visit

12 New LEISHMA NEWS Summary CaniLeish... the first vaccine in Europe against canine leishmaniosis. proven high efficacy under extreme field conditions. fourfold reduction in the risk of developing the clinical disease. provides a high level of risk reduction through ESP vaccine technology and specific stimulation of cellular immunity against the parasite L. infantum. takes you to a new level of protection with safe, effective and long-lasting risk reduction. The results of cutting-edge research, and 20 years of collaboration by high-level scientists 12 involving state-ofthe-art vaccination technology 13. References. 1. Baneth G, Koutinas AF, Solano-Gallego L, et al. Canine leishmaniosis: new concepts and insights on an expanding zoonosis: partone. Trends Parasitology, 2008; 24: Moreno J, Alvar J. Canine leishmaniasis: epidemiological risk and the experimental model. Trends Parasitol, 2002; 18(9): Maroli M, Rossi L, Baldelli R, et al. The northward spread of leishmaniasis in Italy: evidence from retrospective and ongoing studies on the canine reservoir and phlebotomine vectors. Trop. Med. Int. Health, 2008; 13: Waiting for ref 5. Roze M. Canine leishmaniasis: A spreading disease. Diagnosis and treatment. EJCAP, 2005; 15: Alvar J, Canavate C, Molina R, et al. Canine leishmaniasis. Adv. Parasitol., 2004; 57: Pinelli E, Killick-Kendrick R, Wagenaar J, et al. Cellular and humoral immune responses in dogs experimentally and naturally infected with L. infantum. Infect. Immun., 1994; 62: Santos-Gomes GM, Rosa R, Leandro C, et al. Cytokine expression during the outcome of canine experimental infection with L.infantum. Vet. Immunol. Immunopathol., 2002; 88: Tizard IR. Veterinary Immunology: an introduction. 8th Edition, Saunders Elsevier, St Louis, Missouri. ISBN: Mori M, Gotoh T. Arginine metabolic enzymes, nitric oxide and infection. J Nutr., 2004;134(10 Suppl):2820S-2825S. 11. Carrillo E, Moreno J. Cytokine profi les in canine visceral leishmaniasis. Vet. Immunol. Immunopathol., 2009; 128: CaniLeish vaccine was developed by BVT (Bio Véto Test), a wholly-owned subsidiary of Virbac, in partnership with IRD (Institut de Recherche pour le Développement), and Virbac s R&D teams. This project is based on an IRD s patented invention relating to Leishmania culture, on which IRD has granted an exclusive patent licence to BVT for animal health applications. 13. Method for the leishmania culture under IRD License. 14. Rosa R, Rodrigues OR, Marques C, Santos-Gomes GM. Leishmania infantum: soluble proteins released by the parasite exert differential effects on host immune response. Experimental parasitology, 2005; 109: NAME OF THE VETERINARY MEDICINAL PRODUCT: CaniLeish lyophilisate and solvent for suspension for injection for dogs QUALITATIVE AND QUANTITATIVE COMPOSITION: Each dose of 1 ml vaccine contains: Lyophilisate: Active substances: Leishmania infantum Excreted Secreted Proteins (ESP) at least 100 μg Adjuvant: Purifi ed extract of Quillaja saponaria (QA-21): 60 μg Solvent: Sodium chloride 9 mg/ml (0.9%) 1 ml. PHARMACEUTICAL FORM: Lyophilisate and solvent for suspension for injection. CLINICAL PARTICULARS -Target species: Dogs. Indications for use, specifying the target species: For the active immunization of Leishmania negative dogs from 6 months of age to reduce the risk to develop an active infection and clinical disease after contact with Leishmania infantum. The effi cacy of the vaccine has been demonstrated in dogs submitted to multiple natural parasite exposure in zones with high infection pressure. Onset of immunity: 4 weeks after the primary vaccination course. Duration of immunity: 1 year after the last (re-)vaccination. Contraindications: Do not use in case of hypersensitivity to the active substance, to the adjuvant or to any of the excipients. Special warnings: Transient antibodies against Leishmania detected by immunofl uorescence antibody test (IFAT) may appear after vaccination. Antibodies due to vaccination can be differentiated from antibodies due to natural infection by using a rapid diagnostic serological test as a fi rst step to a differential diagnosis. In areas of low or no infection pressure a benefi t/risk assessment must be undertaken by the veterinarian before deciding to use the vaccine in dogs. The impact of the vaccine in terms of public health and control of the human infection cannot be estimated from available data. Special precautions for use in animals: Vaccinate only healthy animals. The effi cacy of vaccination in dogs already infected has not been investigated and therefore cannot be recommended. In dogs developing a leishmaniosis (active infection and/or disease) despite vaccination, proceeding with vaccine injections showed no benefi t. Injection of the vaccine to dogs already infected by Leishmania infantum did not show any specifi c adverse reactions other than those described below. The detection of Leishmania infection using a rapid serological diagnostic test is recommended prior to vaccination. In case of anaphylactic reaction appropriate symptomatic treatment should be administered. De-worming of infested dogs prior to vaccination is recommended. Vaccination should not prevent other measures taken to reduce exposure to sandfl ies. Special precautions to be taken by the person administering the veterinary medicinal product to animals: In case of accidental self-injection, seek medical advice immediately and show the package leafl et or the label to the physician. Adverse reactions (frequency and seriousness): After injection, moderate and transient local reactions may occur such as swelling, nodule, pain on palpation or erythema. These reactions resolve spontaneously within 2 to 15 days. Other transient signs commonly seen following vaccination may be observed such as hyperthermia, apathy and digestive disorders lasting 1 to 6 days. Allergic-type reactions are uncommon and appropriate symptomatic treatment should then be administered. Use during pregnancy, lactation or lay: The safety of the veterinary medicinal product has not been established during pregnancy and lactation. Therefore, the use is not recommended during pregnancy and lactation. Interaction with other medicinal products and other forms of interaction: No information is available on the safety and effi cacy of this vaccine when used with any other veterinary medicinal product. A decision to use this vaccine before or after any other veterinary medicinal product therefore needs to be made on a case by case basis. Amounts to be administered and administration route: Subcutaneous use. After reconstitution of the lyophilisate with the solvent, shake gently and administer immediately one dose of 1 ml subcutaneously according to the following vaccination schedule: Primary vaccination course: First dose from 6 months of age, Second dose 3 weeks later, Third dose 3 weeks after the 2 nd injection. Annual re-vaccination: One booster injection of a single dose should be given 1 year after the third injection and annually thereafter. Overdose (symptoms, emergency procedures, antidotes), if necessary: No adverse reactions other than those mentioned in section 4.6 were observed after the administration of a double-dose of the vaccine. PHARMACEUTICAL PARTICULARS: Incompatibilities: In the absence of compatibility studies, this veterinary medicinal product must not be mixed with other veterinary medicinal products. Shelf life: Shelf life of the veterinary medicinal product as packaged for sale: 2 years. Shelf life after fi rst opening the immediate packaging: use immediately after reconstitution. Special precautions for storage: Store and transport refrigerated (2oC - 8oC). Protect from light. Special precautions for the disposal of unused veterinary medicinal product or waste materials derived from the use of such products: Any unused veterinary medicinal product or waste materials derived from such veterinary medicinal products should be disposed of in accordance with local requirements. POM-V VI 04/02/11 For more information please contact Virbac on Virbac Ltd, Windmill Avenue, Woolpit Business Park, Woolpit, Suffolk IP30 9UP enquiries@virbac.co.uk Use medicines responsibly.