Zoetis Scientists Present Positive Efficacy Data for Investigational Triple Combination Parasiticide at American Heartworm Society Meeting

The results from effectiveness studies in dogs treated with the combination product demonstrated that no adult heartworms were recovered from animals in the laboratory studies and no positive test results for adult heartworms were obtained from dogs in the field study. The product was well-tolerated in all studies presented.

In addition, data from a separate study, which tested the efficacy of oral moxidectin at doses ranging from 3 to 60 µg/kg against three confirmed macrocyclic lactone resistant heartworm strains, served as the basis for selecting the dose of moxidectin included in the investigational combination product. In this study, moxidectin at 24µg/kg given monthly for three consecutive months demonstrated a high level of efficacy in reducing the development of heartworms in these dogs.

Dr. Tom McTier, Research Director and Therapeutic Area Head for Companion Animal Parasitology, Zoetis Veterinary Medicine Research and Development, and one of the AHS presenters stated, “Independent investigators have confirmed that multiple strains of D. immitis that are resistant to macrocyclic lactones have been identified in the U.S. (1-6). Our data support the decision to use a 24 µg/kg dose of moxidectin in our investigational combination product.”

The abstracts are available to conference attendees only at this time, but Zoetis has submitted these papers to be published in peer-reviewed scientific journals and expects them to be available publicly in the coming weeks.

As previously disclosed in its second quarter earnings, Zoetis’ combination parasiticide product is in regulatory review in the U.S., Canada, Brazil, Australia and Japan, as well as with the European Medicines Agency. If approved, the company anticipates this product coming to market in 2020.

About Heartworm Disease

Canine heartworm disease is a serious, potentially fatal condition that can result in severe lung disease, heart failure and damage to other internal organs. The disease is caused by a filarial parasite, Dirofilaria immitis, which is transmitted to dogs though the bite of an infected mosquito. Adult worms live in the heart, lungs and associated blood vessels of an infected animal (7). The Companion Animal Parasite Council (CAPC) recommends annual heartworm testing and prevention of heartworm infection though the use of year round preventatives in all dogs (8).

About Zoetis

Zoetis is the leading animal health company, dedicated to supporting its customers and their businesses. Building on more than 65 years of experience in animal health, Zoetis discovers, develops, manufactures and commercializes medicines, vaccines and diagnostic products, which are complemented by biodevices, genetic tests and a range of services. Zoetis serves veterinarians, livestock producers and people who raise and care for farm and companion animals with sales of its products in more than 100 countries. In 2018, the company generated annual revenue of $5.8 billion with approximately 10,000 employees. For more information, visit www.zoetis.com.

DISCLOSURE NOTICES

Forward-Looking Statements: This press release contains forward-looking statements, which reflect the current views of Zoetis with respect to business plans or prospects, expectations regarding products, regulatory approvals and other future events. These statements are not guarantees of future performance or actions. Forward-looking statements are subject to risks and uncertainties. If one or more of these risks or uncertainties materialize, or if management's underlying assumptions prove to be incorrect, actual results may differ materially from those contemplated by a forward-looking statement. Forward-looking statements speak only as of the date on which they are made. Zoetis expressly disclaims any obligation to update or revise any forward-looking statement, whether as a result of new information, future events or otherwise. A further list and description of risks, uncertainties and other matters can be found in our Annual Report on Form 10-K for the fiscal year ended December 31, 2018, including in the sections thereof captioned “Forward-Looking Statements and Factors That May Affect Future Results” and “Item 1A. Risk Factors,” in our Quarterly Reports on Form 10-Q and in our Current Reports on Form 8-K. These filings and subsequent filings are available online at www.sec.gov, www.zoetis.com, or on request from Zoetis.

References (as of August 26^th)

1. Pulaski CN, Malone JB, Bourguinat C, Prichard R, Geary T, Ward DR, et al. Establishment of macrocyclic lactone resistant Dirofilaria immitis isolates in experimentally infected laboratory dogs. Parasit Vectors. 2014;7:494.
2. Bourguinat C, Lee A, Lizunda R, Blagburn B, Liotta J, Kraus M, et al. Macrocyclic lactone resistance in Dirofilaria immitis: failure of heartworm preventives and investigation of genetic markers for resistance. Vet Parasitol. 2015:210;167–78.
3. Maclean MJ, Savadelis MD, Coates R, Dzimianski M, Jones C, Benbow C, et al. Does evaluation of in vitro microfiliarial motility reflect the resistance status of Dirofilaria immitis isolates to macrocyclic lactones? Parasit Vectors. 2017:10(Suppl. 2);480.
4. Blagburn BL, Arther RG, Dillon AR, Butler JM, Bowles JV, von Simpson C, Zolynas R. Efficacy of four commercially available heartworm preventive products against the JYD-34 laboratory strain of Dirofilaria immitis. Parasit Vectors. 2016:9;191.
5. McTier TL, Six RH, Pullins A, Chapin S, McCall JW, Rugg D, et al. Efficacy of oral moxidectin against susceptible and resistant isolates of Dirofilaria immitis in dogs. Parasit Vectors. 2017:10(Suppl. 2);482.
6. Ballesteros C, Pulaski C N, Bourguinat C, Keller K, Prichard RK, Geary TG. Clinical validation of molecular markers of macrocyclic lactone resistance in Dirofilaria immitis. Int J Parasitol Drugs Drug Resist. 2018;8:596–606.
7. www.fda.gov/animal-veterinary-literacy/keep-worms-out -your pets-heart-facts-about-heartworm-disease
8. www.capcvet.org/guidelines/heartworm

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