Steve Dale presented both sides on a recent ‘Pet Central’
(which is available in our audio archive).
Here’s Steve’s print story on the topic that impacts
all dog owners. Heartworm
Preventative Recalled
Amidst Veterinary Confusion, Contradictory Research,
Passionate Pet Owners Pleas to Discontinue Product…Expert Panel
to Decide Outcome
By
Steve Dale
ProHeart
6 is the first ever pharmaceutical for pets to be recalled by
the United States Food and Drug Administration. The recall of
this preventative for canine heartworm disease came at the FDA’s
request, announced September 3. Unlike other heartworm preventatives,
(which are monthly chewables or pills) this one is an injectable
given by a veterinarian, and it has a six month duration.
In
other ways, the FDA recall is also unique. Dr. Thomas Nelson,
president of the American Heartworm Society seems to represent
the feeling of many veterinarians, “I have not seen the
science to substantiate the need for a recall,” he says.
The
professionals who treat the pets suggest the FDA has been pushed
to take their position by watchdog groups of ordinary consumers
who have organized on the Internet.
According
to both the manufacturer of ProHeart 6, Overland, KS-based Fort
Dodge Animal Health and the FDA, there have been 5,552 report
adverse events (side effects) reported since the product’s
release in the summer of 2001, and 500 deaths.
Fort
Dodge and the FDA agree the majority of those side effects have
been minor in nature such as irritation or swelling at the site
of the injection. At a recent telephone press conference, even
Dr. Stephen Sundloff, director for veterinary medicine at the
FDA indicated not all deaths may be directly attributed to ProHeart
6. He explained that the FDA assigns a causality score on each
report of death, from a very remote association with the drug
to a highly likely link to the drug. He said that most deaths
were in the low range of probability of association with ProHeart
6.
“It’s
clear too many dogs are dying and there is a direct link to ProHeart
6,” says Meri Christensen of Watertown, WI. In April of
2003, her dogs were given the injection. “It seemed like
a good idea at the time,” she says. “One injection
and then I don’t have to worry about remembering the monthly
heartworm pills for six months. I just wasn’t feeling well
that day and didn’t think to ask the vet about side-effects.
You’d think the vet might offer that information, but that
didn’t happen.”
One
of her dogs suffered no ill effects, but the other, Augie, her
champion dog in Flyball (a canine sport) began to act lethargic.
Augie was soon diagnosed by a second vet with an autoimmune disease.
That second vet believed the disease was a direct result of the
ProHeart injection.
When
asked at the teleconference what type of side-effects pet owners
should be most watchful for, Sundloff mentioned lethargy, vomiting,
bleeding and other generalized symptoms. However, more problematic
are anecdotal reports of fatal autoimmune issues and seizures
being consistent as a reaction.
Christensen
fought valiantly to save her dog. “But when lesions began
to appear on Augie’s tongue, and then all over his body,”
she pauses. “I can still barely talk about it. There was
no reason this wonderful dog had to die, but he did and on my
birthday (in August, 2003).”
Christensen
joined a previously organized effort on the Internet to warn consumers,
alert the media (stories on ProHeart 6 made the rounds on many
TV and radio stations, and in newspapers several months back)
and ultimately get the product banned. “We feel it’s
unsafe, and someone has to speak up for dogs,” she says.
“I
understand the emotional impact these pet owners feel,”
says Dr. Rami Cobb, vice president of Pharmaceutical Research
& Development at Fort Dodge, who doesn’t deny that some
deaths are attributed to ProHeart 6. “After all, it is a
drug – the reality is that all drugs can result in a potentially
a severe reaction. But we’ve had (administered) 18 million
doses of it. Even at the reported numbers (including those that
the FDA concedes may not be linked to ProHeart 6 with certainty)
we are still within WHO (World Health Organization) guidelines.”
Cobb
says she’s mystified about why the same drug has been prescribed
as the most often used heartworm preventative in Australia (since
2000) and in Italy, and their regulatory agencies don’t
have an issue.
“You’d
figure the American Heartworm Society would be hearing from veterinarians
from all over America who are having problems with ProHeart, but
we’re not,” Nelson adds.
There’s
clearly a breach between what veterinarians are reporting and
what groups on the Internet contend. Dr. Larry Glickman, professor
of epidemiology and environmental medicine at Purdue University
School of Veterinary Medicine – West Lafayette, IN says
he just wants to learn the truth. Like Nelson, he has no special
interest in Ft. Dodge.
Glickman
revealed for this column his findings (which have also been reported
to both the FDA and Ft. Dodge, but until now not to the media),
looking at the pure data of over 400 veterinary clinics all operated
by Banfield. It’s rare to find one source for data in the
human or animal health field, and Glickman, has access to the
data in the computer system for all Banfield clinics. He researched
dogs given ProHeart 6 from February of 2003 through January of
2004.
The
data did not fully jive with the FDA or Fort Dodge accounts based
on previous complaints. Glickman’s data indicates not a
single death was associated with ProHeart 6. Also, 4.4 of each
10,000 dogs dosed with ProHeart 6 alone (not given in conjunction
with another vaccine) had a reported a side effect or adverse
response; of those 0.8 in 10,000 were considered serious or life
threatening. What’s more, anecdotal (unverified) reports
had suggested that ProHeart 6 was more likely to create a side
effect when given in conjunction with vaccines (which it often
was);Glickman’s research showed this was not true.
While
this system of gathering data is not perfect, it’s arguably
the closest thing to methodically going through real life records.
Had Glickman been given more time to accumulate data, he says
he certainly would have learned more. “This is actually
a wonderful opportunity to objectively look at a product retrospectively
and learn,” he says. “Certainly, the clinical trials
required for approval for any drug going to market isn’t
the same as real world experience.”
The
FDA and Ft. Dodge have agreed to create an independent advisory
panel to review real world safety data concerning ProHeart 6.
“We don’t really understand why we are seeing the
problems we are seeing,” Sundloff said at the teleconference.
Glickman
says, “The first goal should be to determine to what extent
those problems actually do exist in the first place, then describe
what those specific problems are, and go from there.”
Nelson
adds, he wishes there was a way to include the number of animals
whose lives have been saved because they’ve used ProHeart
6 into the data. “For people who might otherwise forget
to dose dogs with a heartworm preventative, ProHeart 6 has been
literally a lifesaver (since heartworm disease is often fatal).
I just hope people understand they need to protect their pets
from heartworm.”
“It’s
all about the truth, Christensen says. “Consumers just want
the truth.” Meanwhile, ProHeart 6 will remain unavailable.
The FDA wouldn’t make additional veterinary personnel available
to comment by this story’s deadline.
