June 05,2008

Grassley asks FDA for rationale in putting ProHeart 6 back on the market


TO: Reporters and Editors
RE: ProHeart 6 back on the market with FDA approval
DA: Thursday, June 5, 2008

Senator Chuck Grassley, Ranking Member of the Committee on Finance, today asked theFood and Drug Administration Commissioner to report on how the agency decided that ProHeart6, a heart worm medication for dogs, is safe to put back on the market after the drug maker pulledit from the market in September 2004.

Senator Grassley said his inquiry is based on information he has received that some FDAsafety officers were left out of internal agency discussions about the safety of ProHeart 6.Today’s request is a continuation of oversight by Senator Grassley of the FDA’s actionswith this drug. A February 6, 2008 Grassley letter to the Commissioner detailed Senator Grassley’s findings regarding the FDA’s removal of thesafety officer who raised questions about ProHeart 6 and that removal being tied to the drugmaker hiring a private investigator to try to discredit the safety officer. The FDA hasn’t yetreplied to Senator Grassley’s February letter. The text of today’s letter follows here.

June 5, 2008

The Honorable Andrew C. von Eschenbach, M.D.
U.S. Food and Drug Administration
5600 Fishers Lane
Rockville, MD 20857

Dear Commissioner von Eschenbach:

I recently learned that the canine heartworm drug, ProHeart 6 will be returning to the market.The drug, as you know, was withdrawn by Wyeth Pharmaceuticals in September 2004 due tosafety concerns.

Based on documents we received, I learned that FDA has held over 18 meetings and 85 phonecalls to discuss ProHeart 6 since it was withdrawn. I understand further that the first meeting todiscuss bringing the drug back onto the market happened on or about January 31, 2005.

However, I do not know if any of these numerous discussions involved FDA safety officials. Ihave also learned that FDA may be relying on safety studies for ProHeart 6 that were performedwith guinea pigs.

In light of my interest in this matter, I am requesting that the Food and Drug Administration(FDA or Agency) provide me with an update on ProHeart 6.

In addition, I would like to remind you that FDA's response to my letter dated February 6, 2008,regarding ProHeart 6 and Dr. Victoria Hampshire is almost four months past the requesteddeadline. I expect to hear from you immediately on the status of the Agency's response.

Also, I would appreciate receiving responses to the following questions by no later than June 19,2008:

1. Were any FDA safety officers involved in any of the 18 meetings and/or 85 telephonecalls regarding the safety of ProHeart 6 and the potential return of the drug to the market? If so,please identify those safety officials, the dates of the meeting/telephone calls and describe theextent of the discussion. If not, please explain why the safety officers were not present fordiscussions.

2. Please also include copies of all agendas and minutes for meetings and teleconferencecalls between FDA and Wyeth/Fort Dodge regarding ProHeart 6 since the drug's removal inSeptember 2004.

3. Since the Veterinary Medicine Advisory Committee meeting in January of 2005, whatstudies were conducted by and/or on behalf of Wyeth/Fort Dodge in support of the return ofProHeart 6 to the market?

What types of studies and how many studies were conducted? We understand that one ofthe primary studies involved guinea pigs not dogs. Therefore please identify all studiesconducted with dogs in the newly reformulated heartworm medication.

What animals and how many animals were included in those studies?

What were the findings of the studies?

Were all of the proposed studies shared with and discussed by the ProHeart 6 workinggroup before they began?

Did any individuals in the ProHeart 6 working group express any concerns and/orobjections with regard to the design of the studies and/or the conclusions reached by Wyeth/FortDodge? If yes, please provide pertinent names, documents, and communications.Were any immunology studies conducted? If so, which veterinary immunologists withinand outside of FDA were consulted by CVM and when were they consulted? If yes, pleaseprovide pertinent names, documents, and communications. And if not, why not?

4. Please describe, in detail, any risk mitigation strategy for safety that FDA may haveproposed for ProHeart 6. Did FDA present this strategy to a Veterinary Medicine AdvisoryCommittee?

5. Please provide any documents or communications related to any Advisory Board meetingheld to discuss among other things bringing ProHeart 6 back onto the market. If there was noAdvisory Board meeting, please explain why one was not convened.

Thank you in advance for your assistance.


Chuck Grassley
United States Senator
Ranking Member of the Committee on Finance