First Cancer Drug for Dogs Approved by FDA

By VLADIMIR NEGRON

June 3, 2009

The Food and Drug Administration approved today the first U.S. drug developed specifically for the treatment of canine cancer.

Palladia, chemically known as toceranib phosphate, is manufactured by Pfizer Animal Health and will be available for use in early 2010.

"This cancer drug approval for dogs is an important step forward for veterinary medicine," Bernadette Dunham, D.V.M., Ph. D., director of FDA's Center for Veterinary medicine, said in a released statement.

"Prior to this approval, veterinarians had to rely on human oncology drugs, without knowledge of how safe or effective they would be for dogs. Today's approval offers dog owners, in consultation with their veterinarian, an option for treatment of their dog's cancer."

Cancer drugs currently used by veterinarians are not approved for use in animals, as they were originally designed for humans. However, according to the Animal Medicinal Drug Use Clarification Act of 1994, vets are allowed to administer human cancer medicine in an "extra-label" manner.

The Palladia tablet, taken orally, is indicated to treat Patnaik grade II or III recurrent cutaneous mast cell tumors with or without regional lymph node involvement. Common side effects include diarrhea, anorexia, lethargy, vomiting, lameness, weight loss, and blood in stool.

Palladia, a tyrosine kinase inhibtor, works in two ways: by killing tumor cells and by cutting off the blood supply to the tumor. In a clinical trial, approximately 60 percent of dogs had their tumors disappear, shrink, or stop growing.

Pfizer estimates 1.2 million new canine cancer cases are reported in the U.S. every year. And because, according to Phizer research, canine mast cell tumors are the second most common tumor type seen in dogs, Palladia is described by many as a new and exciting treatment option for vets.