FORT WORTH, Texas Kelly, a 10-year-old chocolate Lab, sports a bright yellow collar with Livestrong embroidered on it.

Like cyclist Lance Armstrong, shes a cancer survivor. In June, Kelly started getting Palladia, the first drug approved by the Food and Drug Administration to treat cancer in dogs.

About a month later, when the playful pooch returned to her veterinarian for tests, her owner got the news she had been hoping for.

I dont see any cancer at all, said Dr. Cheryl Harris, a Dallas vet who is board-certified in oncology.

For Kellys owner, Pam Greenberg, the news came as a huge relief after another vet diagnosed the dog with a malignant mast cell tumor and an enlarged lymph node in her chest.

The prognosis wasnt good, she said. Maybe three to nine months.

Greenberg hit the Internet and discovered that Pfizer, the maker of Palladia, had received FDA approval for the drug in June, but for limited use. Only vets certified in oncology are allowed to give the drug until it becomes widely available early next year.

While surgery is the first line of treatment for dogs with mast cell tumors, many dogs dont have that option, Harris said. The malignant tumor accounts for about 20 percent of skin cancer in dogs. It strikes all breeds but is often found in Labradors, boxers and Boston terriers.

Until the development of Palladia, veterinarians had to rely on human cancer drugs without knowing the dosage, safety or effectiveness in animals.

About 60 percent of dogs older than 6 are diagnosed with cancer, and nearly half the deaths in pets older than 10 result from the disease, according to the Pet Cancer Foundation.

Palladia joins a growing list of FDA-approved drugs developed specifically for companion animals. Within the last two years, the FDA has approved three other drugs developed by Pfizers veterinary division: Slentrol for obesity, Cerenia for motion sickness, and Convenia, the first single-dose injected antibiotic for skin infections in dogs and cats. Novartis, Eli Lilly and other pharmaceutical giants are also making medicines for companion animals.

Animal health is big business in a country where many people treat their pets like family members. An estimated 62 percent of U.S. households own a pet, equivalent to 71.4 million homes, according to the American Pet Products Association.

This year, pet owners are expected to spend $45.4 billion on their animal companions, $22.4 billion of that on veterinary care, over-the-counter medications and supplies.

Since the FDA approved Palladia, Harris said, she has been inundated with calls from people interested in the drug for their dogs.

People definitely see their pets as four-legged children, Harris said.