New cancer drug carries high hopes of oncologists
February 24, 2009 (published)
By Gilbert Mohtes-Chan
Veterinarians always welcome new cancer drugs to fight the No. 1 killer of dogs and other companion animals.
they might have a new weapon in their armamentarium. Clinical trials
are underway in the United States for Paccal Vet, a form of paclitaxel
that could become the nation’s first conventional cytotoxic
chemotherapy drug for treating canine mast cell tumors. It's the first
multi-center, large-scale trial of its kind that's truly international,
The research is creating a buzz among oncologists in veterinary medicine.
a year ago, a Swedish pharmaceutical company contacted several
veterinary oncologists to evaluate the potentially groundbreaking
chemotherapeutic treatment in dogs in the United States. By November, a
large-scale clinical trial for Paccal Vet was launched in multiple
veterinary centers to treat dogs with mast cell tumors, one of the most
common types of skin cancer in dogs.
Two clinical trials
completed in Europe for Sweden’s Oasmia Pharmaceutical’s product have
shown encouraging results, insiders say. The most significant
preliminary finding was the absence of severe allergic reactions, which
have previously hampered the use of paclitaxel for this condition.
U.S. Food and Drug Administration (FDA) reportedly has taken note,
recognizing the possible medical breakthrough in treating cancers in
animals. Last month, the agency's Center for Veterinary Medicine agreed
to expedite its review of Paccal Vet, a move that could cut the
government review time in half and speed up registration of the drug
The FDA’s decision “will benefit our ongoing phase
III study in the U.S. and EU a great deal and an earlier launch on the
very important U.S. market,” Oasmia Chief Executive Officer Julian
Aleksov said in a statement.
If there are no hitches, Paccal Vet could hit the market within two years, one expert said.
the meantime, oncologists like Dr. Robert Rosenthal caution against the
initial optimism and what appear to be stunning results.
results of the proposed study in the United States will be eagerly
anticipated, but such anticipation should be tempered until results of
that and the European work are available for more general critical
review,” said Rosenthal, a Veterinary Information Network consultant.
“That the adverse effects of the conventional carrier have been
eliminated is good news, but it certainly remains to be seen to what
extent any new formulation of paclitaxel is effective in the clinic.
“It is incumbent on all oncologists not to be too optimistic too early in a situation like this one.”
researchers and veterinarians are encouraged by the international scope
of a Paccal Vet review and the investment Oasmia is making.
have a company looking to put money into the veterinary oncology market
and trying to come up with newer drugs that will help us,” said Dr.
Craig Clifford, a veterinary oncologist and director of clinical
research at Red Bank Veterinary Hospital in Tinton Falls, N.J. “It
takes a lot of money to get something approved for a specific species.
A lot of companies don’t want to go through with that.”
study will tap a diversity of dogs from coast-to-coast. There are 12
private veterinary clinics in 10 states and Washington, D.C. and six
universities participating in the trial. As of January, 40 dogs had
been treated and the goal is to enroll up to 220 during the next six
months, according to Animal Clinical Investigation, a Washington, D.C.
group overseeing the study's implementation.
Study subjects can
vary in age, breed and gender but must have intermediate- to high-grade
tumors and no prior radiation or chemotherapy treatment. Dog owners pay
only for the initial consultation fee. The remaining expenses are
covered by the drug company.
Results should determine the
effectiveness and safety of Paccal Vet compared to lomustine (CeeNu), a
standard chemotherapy treatment for mast cell tumors. Lomustine
treatment has gained popularity during recent years because it is
fairly inexpensive, easy to administer in pill form and relatively
Dr. Tony Rusk, vice president of clinical
affairs for Animal Clinical Investigation, said the veterinary oncology
community is interested in having approved veterinary products in the
oncology market. “We are extremely excited and motivated in studies
like this. It may result in a veterinary product for cancer.”
is good news for animals. Roughly half of all dogs 10 years or older
die of cancer-related diseases. It is estimated that one in four dogs
will develop some form of tumor during its lifetime. Certain breeds
such as Beagles, Bulldogs and Labrador Retrievers have a higher risk of
developing mast cell tumors.
Increasingly, dog owners are becoming more aware about pets with cancer and opting for treatment, Clifford said.
perceptions of pets have certainly changed in the last 20 years," he
said. "Before the dog was the family dog. If the dog was sick you put
the dog down and got another dog. Now the dog is a family member. We
have more and more owners that are electing to go through a
chemotherapy for their pets."
Surgery usually is a first-line
treatment for mast cell tumors, especially the disease is limited to a
single mass on the skin, but it's generally considered insufficient at
stopping more serious, high-grade tumors or disease that already has
metastasized. Chemotherapeutic options for such tumors include human
medications like lomustine and vinblastine.
oncologists also have considered the anticancer drug paclitaxel as a
potential chemotherapeutic for a variety of canine cancers, but there
are drawbacks. Paclitaxel is not water soluble. Taxol, an approved
treatment for human breast and ovarian cancer, uses the castor
oil-based elixir, Cremophor EL to suspend the paclitaxel so that it can
be administered intravenously to patients.
However, Cremophor EL
is known to cause severe side effects. To lessen the impact, cancer
patients need to take medications in advance and go through a lengthy
A 2004 study published in the Journal of
Veterinary Internal Medicine found that 64 percent of dogs receiving
paclitaxel experienced allergic reactions post treatment. Nearly a
quarter required hospitalization, and more than one in 10 died of
For Paccal Vet, Oasmia scientists developed a new
water-soluble formulation that eliminates the need for Cremophor. The
new treatment requires no pre-medication, dramatically shortens
infusion time and eliminates serious side effects, according to company
Last month, Oasmia publicly detailed highlights from
two clinical studies in Europe. The infusion times were cut to about 30
minutes in both trials.
In the first study dealing with dosage
amounts and different types of cancers, 74 percent of the dogs
responded to the drug. The phase III study, focusing on dogs with
serious mast cell tumors, showed a 70-percent response rate and a
median of 235 days in which the disease remained stable after
treatment. There were no unexpected, severe side effects, the company
If the current study leads to successful licensing of
Paccal Vet in the United States, this drug may have other implications
in treating other kinds of cancers.