Feline Oral Squamous Cell Carcinoma

Examine the efficacy of toceranib phosphate (Palladia) as a primary and/or adjuvant agent in the treatment of feline oral squamous cell carcinoma

Oral squamous cell carcinomas account for approximately 90% of feline oral tumors and at this time there are no consistently effective treatment options. These tumors are biologically aggressive and locally invasive. Median survival time in untreated cases is approximately 60 days. Radiation therapy or chemotherapy used alone is generally ineffective.  Accelerated radiation protocols appear to have some efficacy. The combination of full course radiation therapy with radiation sensitizers or chemotherapy improves the number of cats that respond to therapy, but overall survival times remain in the 4-6 month range. Unfortunately, this treatment option comes with significant expense. 

Palladia is a tyrosine kinase inhibitor that affects the development of blood vessels by targeting receptor tyrosine kinases within tumors. By blocking the signaling of these pathways tumor growth can be slowed. The presence of these receptors (VEGF and VEGFRs) has been well documented in human oral squamous cell carcinomas.  This has not been evaluated yet in feline tumors.  Evidence continues to accumulate indicating that Palladia can also increase the sensitivity of tumor cells to radiation therapy and that Palladia has some primary activity in feline oral squamous cell carcinomas. Because of these effects, clinical investigation of Palladia as therapy for feline oral squamous cell carcinoma alone or in combination with radiation therapy is indicated. 

Cats deemed eligible based on prior evaluation will be treated with Palladia (3 to 3.25 mg/kg every other day at the investigator’s discretion). Whether to treat with radiation therapy will be the owner’s decision. Radiation patients will receive 6 radiation treatments over three weeks to a total dose of 36 Gy. Your cat will receive a physical examination, complete blood count, toxicity assessment, and drug accountability weekly for the first three weeks, then at week 5, then at four-week intervals. 

Your cat will receive the drug at no cost. We expect that treatment with Palladia will benefit some cats with oral squamous cell carcinoma by increasing response rates and prolonging disease free intervals and overall survival times.

• Annette Smith, D.V.M.
• Oncology Service Director
• Department of Clinical Sciences
• 334-844-4690
• smith30@auburn.edu