Dear Committee Members,
I want to applaud the FDA concerning the action they
have taken to protect the public by the with-drawl of
Proheart 6.
The adverse reactions that I have witnessed fall into
three categories; Neuro-toxicity manifesting in the
form of seizures, pulmonary symptoms including massive
pulmonary thromboembolisms, and allergic reactions including
hemorrhagic gastroenteritis and frequently progressing
to disseminated intravascular coagulation.
I pose that the following questions need to be answered
before this drug can be returned to the market.
1. Are these problems due to an inherent problem with
the drug moxidectin, instability of the microspheres,
allergy to the micorpsphere coating, or are they due
to mis-handleding of the drug by Veterinarians or some
of both?
2. If Proheart 6 is injected thru too small of a gauge
needle, or if the bottle of reconstituted drug is shaken
vigorously after several nights of refrigeration could
this cause disruption of the microspheres? Could disruption
of the micropspheres cause pre-mature release of the
moxidectin, moxidectin overdose, and result in seizures?
Or could this be a manufacturing problem?
3. We know moxidectin is a more potent filaracide than
ivermectin or milbemycim. In a letter I have from Dr
Toni Triego whose patient died from an adverse reaction
to proheart 6, she states that Dr La Roch at Ft Dodge
told her they knew Proheart 6 could kill L4 larvae.
Does the death of L4, newly emerged young adult larvae
and possibly migrating intestinal worm larvae, all of
which cannot be detected by available testing methods,
pose a fatal risk to our patients? How can this risk
be avoided?
4. How does proheart 6 cause hemorrhagic gastroenteritis?
Is this due to death of migrating larvae or is this
a manifestation of an allergic reaction?
5. Are dogs allergic to the microsphere coating? Is
the number of dogs allergic to this drug excessive necessitating
withdrawal? Why do these anaphylactic reactions this
result in DIC?
6. If microspheres are injected into a dog do some
of them inter the circulation? What is the impact of
circulating microspheres on the kidneys and lungs? Studies
have shown microspheres can cause pulmonary hypertention
in some species.
I have a suggestion which could increase product safety.
Unit dosing would help to prevent many of the mis-handling
and storage errors. This has been widely mandated for
human drugs.
I want to express dismay at the method in which Ft
Dodge marketed this product. Please help me to understand
why a company would choose a person whose presentations
use so much profanity? Dr Whitford is not a Board certified
cardiologist, parasitologist or pharmacologist. He has
nothing to qualify him to educate DVMs on the use of
a drug. In his presentation he focused on one point.
Veterinarians will go broke due to competition form
Pet Med Express if they do not switch their clients
to this product. He repeatedly said that none of the
Adverse Drug experiences reported to the DFDA were due
to Proheart 6. He stated that all allergic reactions
could be treated with benadryl. Since when is benadryl
the standard of care for DIC? In my humble opinion Ft
Dodge is responsible for the mi-handling of this drug
by Veterinarians and the deaths of pets that have resulted
because they failed to warn Veterinarians about the
side effects, they failed to adequately inform DVMs
on the proper handling of the drug, the consequences
of not following label directions, and how to diagnose
or treat adverse reactions. This lack of responsibility
is not in the best interest of Ft Dodge, it is not in
the best interest of our patients, and it is not in
the best interest of the Veterinary profession.
I made several calls to Ft Dodge about adverse reactions
to Proheart 6. I was told by a Veterinarian in research
and development that marketing has a larger budget than
research and development and that the marketing does
not ask questions of or even talk to research and development.
When I called to report an adverse reaction, I was told
that FDA ADEs are not filtered. That if a dog was hit
by a car the day after an injection of Proheart 6 it
would be recorded as an adverse reaction. In looking
at the ADEs reported I don’t see and "hit
by cars" or any adverse reaction reports that are
lacking in common sense.
There is nothing urgent about the need to return Proheart
6 to the market. We have several heartworm preventatives
available with excellent safety records. Our primary
doctrine is “Above all, do no harm.” I hope
the FDA will take time to insure that the safety of
our patients is insured.
Sincerely,
Dr Bob Rogers
