Toceranib Phosphate (Palladia®) Approved for Canine Mast Cell Tumors

Posted on July 5, 2009

In early June, 2009 the Food and Drug Administration (FDA) approved toceranib phosphate, the first drug specifically FDA licensed for treatment of canine neoplasia. To many in the field, the development and approval of this drug represents a major step forward in both animal and comparative oncology. A recently published randomized and blinded study (Clinical Cancer Research, June 1, 2009), showed efficacy in dogs with recurrent mast cell tumors after surgery. Toceranib phosphate is a receptor tyrosine kinase (RTK) inhibitor. Many mast cell tumors in dogs are known to express mutations in c-kit which is a RTK that promotes survival, growth, and malignancy in these tumors.

All previously used cancer chemotherapeutics in veterinary medicine have been used in an “extra-label” fashion per the rules of the Animal Medicinal Drug Use Clarification Act (AMDUCA) of 1994. The FDA’s approval of toceranib follows the 2007 conditional approval of a melanoma vaccine for use in dogs by the United States Department of Agriculture (USDA) which represented the first approved therapeutic vaccine for cancer in humans or animals.

In addition to gaining the attention of those in the veterinary oncology field, approval of toceranib, as a landmark achievement, makes it fair game for board examination questions. It is probably too late in the year for it to make it into 2009 exams but could appear as soon as 2010. You should be able to recognize the drug name as an FDA approved cancer treatment and know that it is a receptor tyrosine kinase inhibitor approved for treatment of mast cell tumors. Specific knowledge of the drug’s efficacy and detailed molecular biology is probably unnecessary for general board exam purposes.