Let's see if this helps-
http://www.fda.gov/bbs/topics/answers/2004/ans01312.htmlSeptember 3, 2004
Fort Dodge to Comply with FDA's Request to Recall ProHeart 6 Injectable Heartworm Product from the Market Due to Serious Health Concerns
"Fort Dodge Animal Health, of Overland Park, Kansas, at FDA's request, has agreed to immediately cease production and recall its heartworm medication ProHeart®6 from the market until the FDA's concerns about adverse reaction reports associated with the product can be resolved. FDA is requesting that the firm continue to conduct research to determine the cause of related adverse reactions and develop a strategy to help prevent such problems in the future before the product is marketed again. The FDA will convene an independent scientific advisory committee to thoroughly evaluate all available data.
"Since the product was approved in June 2001, Fort Dodge Animal Health has cooperated with FDA to investigate numerous adverse event reports. As a result, Fort Dodge has voluntarily changed the label to include post approval safety information including rare reports of death and a caution to practitioners that dogs should have a negative test for heartworm before administration.
"Despite these label changes, FDA is still receiving unexplained adverse event reports, some of them severe. FDA's concern is based on voluntary self-reporting to FDA by veterinarians and owners whose dogs have suffered adverse drug experiences (ADEs) to ProHeart®6 (which contains the drug moxidectin) as well as the mandatory reporting of adverse events by Fort Dodge Animal Health.
"As of August 4, 2004, FDA's Center for Veterinary Medicine (CVM) had received 5,552 adverse event reports for ProHeart®6. The actual number of adverse events is likely even higher because studies show that only a fraction of actual ADEs are reported.
"The Agency has observed an increase in the number of cases associated with liver and bleeding abnormalities followed in some cases by death." http://www.fda.gov/cvm/PH6QA.htmFDA Questions and Answers-ProHeart 6
Q: Why did CVM ask Fort Dodge Animal Health to recall ProHeart®6?
A:
Since the product was approved in June 2001, we have received reports of nearly 5,500 serious adverse drug reactions attributed to ProHeart® 6. After evaluating these reports, the Center for Veterinary Medicine (CVM) determined that at least 1,900 of those were unrelated to the concurrent administration of other drugs or vaccines. The clinical signs contained in those reports were possibly or probably associated with the ProHeart®6 injection. Many of the adverse events were severe, including more than 600 reports of death.
The actual incidence of adverse events is likely to be even higher than reported, because studies show that only a fraction of actual adverse reactions are reported. Based on its experience with adverse drug reactions attributed to animal drugs over the years, CVM considers the number and severity of those attributed to ProHeart®6 to be unacceptable, even when considering the number of doses of the drug that have been administered.http://www.nytimes.com/2005/12/06/politics/06fda.html?_r=1&scp=2&sq=proheart&st=nyt&oref=sloginNew York Times December 5, 2005
"A federal drug safety official said Monday that her career had been sidetracked and her reputation tarnished after complaints from a drug maker led the Food and Drug Administration to suspend her from reviewing a heartworm medicine for dogs.
"The reviewer, Dr. Victoria Hampshire, was eventually cleared of any wrongdoing. But Dr. Hampshire said she was angry that agency officials had failed to inform her of the accusations or give her a chance to explain herself before taking actions that, she said, hurt her career.
"In 2003, Dr. Hampshire raised concerns about ProHeart 6, a heartworm drug made by Wyeth that was later linked with the deaths of 500 dogs and illnesses in 5,000 more. Under pressure from the F.D.A., Wyeth withdrew the drug last year.
"In a Nov. 29, 2004, meeting, Wyeth's chief executive, Robert A. Essner, raised concerns about Dr. Hampshire with Lester M. Crawford, then the agency's commissioner, said Dr. Hampshire's lawyer, whose account was confirmed by agency officials. The lawyer, Mark Cohen of the Government Accountability Project, a private group that represents whistle-blowers, said Wyeth had hired a private investigator to "dig up dirt" about Dr. Hampshire." http://concernedvet.netfirms.com/"Now that the post-approval data is beginning to become available, there are indications that it is far more likely to have some serious adverse effects (including possible death in rare instances) than other perfectly satisfactory and better characterized heartworm preventatives."
(Written prior to the 2004 withdrawal of the drug)
http://concernedvet.netfirms.com/letter.htmlFort Dodge letter to vets before the 2004 withdrawal.
http://concernedvet.netfirms.com/effects.htmlhttp://www.fda.gov/cvm/Documents/Proheart6RiskMAP.pdfFort Dodge Risk Management Program ProHeart 6--dated May 29, 2008--a 63 page long pdf almost 10 MB in size. Pages 6 and 7 describe how the solvent material was tested on guinea pigs. Page 60 shows the owner consent one must sign before the drug is given. It speaks of the possible side effects.
http://www.fda.gov/bbs/topics/NEWS/2008/NEW01844.htmlJune 5, 2008 FDA Announces Limited Return of Heartworm Drug to U.S. Market
"The U.S. Food and Drug Administration (FDA) today announced a limited return of a reformulated heartworm prevention drug for dogs,
which had been withdrawn because of serious, life-threatening adverse reactions, including loss of appetite, lethargy; vomiting, seizures, difficulty walking, jaundice (a yellowish appearance); and bleeding disorders, allergies, convulsions, followed in some cases by death. "ProHeart 6 (moxidectin) Sustained Release Injectable for Dogs, NADA 141-189, manufactured by Fort Dodge Animal Health, Overland Park, Kan., is an approved injectable sustained-release heartworm prevention product for dogs. FDA is concurring with its limited return to the U.S. veterinary market under a risk minimization and restricted distribution program designed to manage the re-introduction of ProHeart 6 to provide for safe, appropriate use of the product while minimizing risk to dogs.
"The return of ProHeart 6 to the market is based on results of additional toxicological and pharmacologic studies by Fort Dodge Animal Health coupled with the low adverse reaction frequency in international markets.
"In 2004, Fort Dodge Animal Health agreed to voluntarily recall the product from the market based upon FDA's concerns regarding reports of serious adverse reactions in dogs following the use of ProHeart 6.
In response to FDA's concerns, the manufacturer conducted additional testing of its product, which indicated that residues of the solvents used in the manufacture of ProHeart 6 may cause allergic reactions.
"The manufacturer has improved the manufacturing specifications for ProHeart 6 to decrease the presence of those residues and has marketed the product in international markets. Few adverse events have been reported with this reformulated product.http://www.jarvm.com/articles/Vol3Iss2/GLICKMAN.pdfThe Glickman/Banfield study of ProHeart 6, published in 2005. Take a look at page 12 where it shows that CDC AND Fort Dodge paid for this study.
My personal thought is that I wasn't comfortable with this form of heartworm preventive prior to its withdrawal from the market and I'm not comfortable with it now that it's returned.
What's striking is that you are asked to sign a consent form detailing the risks and possible adverse effects before the injection can be given. None of the oral or topical heartworm prevention meds require this--only ProHeart 6. Since I don't need to sign a consent form to get a prescription for my dog's monthly oral heartworm med, it says to me that ProHeart 6 must be riskier than the other forms of heartworm prevension on the market.
The biggest little word in any language is the word "
NO", which everyone has the right to say when this treatment is offered. You absolutely have the right to say you don't want to have this used on your dog and will accept oral or topical heartworm meds only. ProHeart 6 is not to be used unless you sign the consent form before it's given--if you don't want it used, then you don't need to sign anything. If everyone who has concerns about ProHeart 6 says "
NO" if it's offered as a heartworm treatment, Fort Dodge won't need to have FDA request the withdrawal of the drug this time. They will be doing it all by themselves due to poor sales.
