1. U.S. Food and Drug Administration Notice: Archived Document The content in this document is provided on the FDA’s website for reference purposes only. It was current when produced, but is no longer maintained and may be outdated.

2. ProHeart 6 Safety Assessment by Fort Dodge Animal Health January 31, 2005

3. Rami Cobb, BVSc (Hons.) MACVSc Vice President Pharmaceutical Research & Development Fort Dodge Animal Health

4. Active ingredient: moxidectin Macrocyclic lactone Anthelmintic agent Dogs, horses, cattle, sheep, swine Co-development with WHO for humans Onchocerciasis (river blindness) ProHeart 6 Introduction

5. Innovative Product A single dose provides 6 months protection from heartworm disease caused by Dirofilaria immitis Treats existing hookworm infections Overcomes compliance failures associated with monthly heartworm preventives ProHeart 6 Introduction

6. Moxidectin Extensive Toxicology Database Receptor-mediated adverse pharmacologic/toxicologic effects not expected (new study) Toxicology studies of up to 2 years in mice and rats and 1 year in dogs showed no adverse histologic or biochemical effects on any organ system Exposure (AUC) of dogs to moxidectin in toxicology studies were 454-fold higher than after 2 doses of ProHeart 6 given 6 months apart (new study) No increase in tumors in 2-year carcinogenicity studies

7. Safety study results demonstrate Wide margin of safety Safe in breeding animals Safe in unique canine populations Ivermectin-sensitive Heartworm positive 100% efficacy at commercial dose 100% efficacy in large number (84) of breeds A total of 770 dogs were evaluated for US registration Pre-Approval ProHeart 6 Clinical Study Results

8. Factors Limiting Heartworm Control in US Dogs Widespread availability of heartworm preventives has not changed the infection rates in last 10 years 240,000 dogs in US tested positive for heartworm nationwide in 2001 One-fifth of surveyed dog owners stopped giving their dogs the monthly oral preventive altogether

9. Approved and marketed globally US – June 2001 Canada, Japan, Italy, France, Spain, Portugal, Greece, Korea ProHeart SR 12 Australia – October 2000 12 months heartworm protection 3 times ProHeart 6 dose ProHeart 6 Approval

10. Rapid and broad acceptance by dog owners and veterinary professionals 24% US market share 47% Australian market share ProHeart 6 Market Experience

11. Source: June 2004 Doane Market Research: Heartworm Tracking Study Brand Share Change 2001 - 2004 Dispensed Units

12. ProHeart 12 - Australia

13. US and Australian AER Reports USAustralia Doses sold18,000,0002,000,000 AER rate 2.5 1.6 (per 10,000 doses) Allergy reporting rate1.3 0.8 (per 10,000 doses) Death reporting rate0.3 0.1 (per 10,000 doses)

14. September 2004: FDAH voluntary recall of ProHeart 6 based on CVM concerns about adverse events Data reviewed by Canadian, Australian, European, and Japanese regulatory authorities Confirmed authority to continue marketing ProHeart 6 Introduction

15. Large independent nation-wide database: Banfield The Pet Hospital™ Nearly 7 million “encounters” (office visits) ProHeart 6, two heartworm preventives, vaccines were evaluated Results demonstrate no clinically significant increase in adverse events following ProHeart 6 treatment ProHeart 6 safety profile similar to 2 monthly heartworm preventives ProHeart 6 Epidemiological Evaluation (presented by Dr. Larry Glickman, Purdue University)

16. Post-marketing monitoring of AERs Overall reporting rate is low Reporting rate is declining Most AERs appear to be allergic and self limiting Assignment of causality confounded by concurrent vaccinations Varied non-allergic AERs reflect diseases often seen in dogs Re-Evaluation of AERs by FDAH (presented by Dr. David Hustead, FDAH)