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U.S. Department of Health and Human Services

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Merial Limited 21-Jun-07


Department of Health and Human Services logoDepartment of Health and Human Services

Public Health Service
Food and Drug Administration

JUN 21 2007



Certified Mail
Return Receipt Requested

NADA 140-971 (L1328)

Liubov Skibo
Director, Regulatory Affairs
Merial Limited
3239 Satellite Boulevard
Duluth, GA 30096

RE: Heartgard® Plus (ivermectin/pyrantel) advertisement in the Journal of the American Veterinary Medical Association (4/1/07 & 4/15/07 issues)


Dear Ms. Skibo:


We, the Division of Surveillance (DOS), Center for Veterinary Medicine, have reviewed your advertisement entitled "Unmatched" in the Journal of American Veterinary Medical Association (JAVMA) for Heartgard® Plus (ivermectin/pyrantel) Chewables for Dogs, NADA 140-971. This advertisement appeared in the April 1 and 15, 2007, JAVMA issues. This advertisement causes Heartgard® Plus to be misbranded within the meaning of section 502(n) of the Federal Food, Drug, and Cosmetic Act (the Act) [21 U.S.C. 352(n)].


Heartgard® Plus is an oral chewable formulation containing ivermectin and pyrantel. It is approved for the prevention of canine heartworm disease by eliminating the tissue stage of heartworm larvae (Diroflaria immitis) for a month (30 days) after infection and for the treatment and control of ascarids (Toxocara canis, Toxocaris leonina) and hookworms (Ancylostoma caninum, Uncinaria stenocephala, Ancylostoma brazillense). It is approved to be administered orally at monthly intervals

Unsubstantiated Claims of Effectiveness

The advertisement in JAVMA makes the claims "Heartworm and zoonosis control in a Real-Beef Chewable" and "Heartgard® Plus harnesses the irresistible power of real beef to make sure dogs get a full dose of heartworm prevention and zoonotic disease treatment and control." These statements imply the drug is effective for controlling and treating zoonotic diseases generally, not only ascarids and hookworms. These statements thus overstate the demonstrated effectiveness of Heartgard® Plus. CVM is not aware of substantial evidence to support this broad range of conditions. If you have supporting data, please submit it to FDA for review. While we acknowledge that the advertisement also states that the drug provides "Both treatment and control of the most common zoonotic intestinal parasites," which would include ascarids and hookworms, this is presented in significantly smaller print than the other two statements and is insufficient to correct the overall misleading impression created by the piece.

In addition, the advertisement includes a testimonial that implies use of the drug in dogs will prevent the zoonotic transmission of toxocariasis and subsequent ocular larval migrans in humans. The statements described in the previous paragraph are on a page showing a picture of a dog being given what appears to be Heartgard® Plus. The dog is linked by its leash to a photo on the opposite page that shows a woman and a child in a public park. Above the photo is the headline, "Never turn a blind eye to the threat of zoonotic disease." The accompanying text details a mother's testimonial of her four year old son who contracted toxocariasis and subsequent unilateral blindness due to ocular larval migrans. The testimonial includes statements linking the prevention of roundworms in dogs to the prevention of transmission to humans, such as:

"Before Christopher's infection we'd heard of roundworms - and we knew that they could be transmitted to people. . . . I urge you, as veterinary professional, to tell pet owners about the risks of these diseases and how to avoid transmission. Talk to them about preventing roundworms and hookworms. "

The overall impression is that the use of Heartgard® Plus in dogs will prevent zoonotic transmission of toxocariasis and subsequent ocular larval migrans in humans. CVM is not aware of substantial evidence or substantial clinical experience to support the effectiveness of Heartgard® Plus for the prevention of toxocariasis, ocular larval migrans, or any other zoonotic disease in humans. Suggestions that the use of Heartgard® Plus in dogs prevents toxocariasis, ocular larval migrans, or any other zoonotic disease in humans, especially in children, is particularly troublesome because early diagnosis and treatment in humans may be delayed.

Conclusion and Requested Action

The advertisement described above overstates the effectiveness of Heartgard® Plus. Accordingly, the drug is misbranded within the meaning of section 502(n) of the Act [21 U.S.C. 352(n)] and FDA implementing regulations at 21 CFR 202.1 (e)(6)(i).

The violations discussed in this letter do not necessarily constitute an exhaustive list. It is your responsibility to ensure that your advertisements and promotional materials for Heartgard® Plus, as well as for your other products, comply with the requirements of the Act and its implementing regulations. Failure to correct the violations discussed above may result in FDA regulatory action without further notice such as seizure and/or injunction.

You should notify this office in writing within fifteen (15) working days of receiving this letter of the steps you have taken to bring your firm into compliance with the law. Your response should include each step that has been taken or will be taken to correct the violations and prevent their recurrence. If corrective action cannot be completed within fifteen (15) working days, state the reason for the delay and the time frame within which the corrections will be completed. Please include copies of any available documentation demonstrating that corrections have been made.

In addition, we request that you immediately cease the dissemination of violative advertisements for Heartgard0 Plus such as those described above. Specifically, you should cease the dissemination of the advertisements in the Journal of the American Veterinary Medical Association concerning Heartgard® Plus and any other materials that may contain similar information. Future advertisements and promotional materials should adequately address the claims for the prevention of heartworm and other intestinal parasites, described in the currently approved labeling, without overstating the effectiveness. Because the violations described above are serious, we request that your submission include a comprehensive plan of action to disseminate a truthful, non-misleading, and complete corrective message about the issues discussed in this letter to the audience(s) that received the violative advertisements.

Please send your written reply to the Food and Drug Administration, Attention: Lynn O. Post, 7519 Standish Place, Rockville, MD 20855. If you have questions regarding any issue in this letter, please contact Lynn O. Post at (240) 276-9062.

Sincerely yours,


Lynn O.Post, DVM, Ph.D. DABVT
Director, Division of Surveillance
Center for Veterinary Medicine