On June 3, 2009, the Food and Drug Administration approved the first drug to treat canine skin-based mast cell tumors. It is made by Pfizer, and should be available from veterinarian offices by 2010.
While this type of cancer is only responsible for 1 out of 5 skin cancer cases in canines, this is a step in the right direction. You can read more about the drug and its approval at http://www.fda.gov/AnimalVeterinary/NewsEvents/CVMUpdates/ucm164250.htm. Be sure to click the links under Additional Information to get the full story.