Cancer Vaccines:  Most of us are familiar with vaccines as a preventive agent, stimulating an immune response directed against foreign proteins. But vaccines can also be designed to be therapeutic and help cancer patients after the diagnosis.  Oncept, mentioned above, is a DNA based vaccine and helps dog's immune system recognize tyrosinase, a protein expressed on melanoma cells.  Several years ago, Listeria based vaccine was developed to direct T-cells to go after HER2/neu proteins expressed by osteosarcoma tumor cells.  The initial study involving eighteen pet dogs demonstrated impressive median survival time compared historical control group.  

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Checkpoint Blockade:  T-cells can be deactivated when special molecules bind to its checkpoint receptors.  These surface receptors play an important role in keeping T-cells from becoming overactive and attacking our healthy tissues.  Some tumors cells take advantage of this mechanism, bind to the checkpoint receptors and turn off the immune system in order to survive.  Drugs called checkpoint blockade drugs can block these tumor cells and ensure that T-cells can do their job.  Investigation into canine checkpoint blockade approaches are being pursued  in laboratories in the US and in Japan.  

Adoptive T-cell Therapy: T-cells are collected from a patient, and ex-vivo (outside the body)  multiplied and activated to better target cancer cells.   The cells are then infused back into the patient, where they can more effective seek out and kill cancer cells.   One company, Elias Animal Health based in Kansas City,  has developed a treatment where they vaccinate a dog with his own cancer cells to produce immune response.  The T-cells are then removed from the patient and "super-charged" outside the body, and are reinfused into the patient.  A clinical trial is underway to test this therapy with dogs with osteosarcoma. 

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