Canine Osteosarcoma

Osteosarcoma (OSA) is the most common type of bone cancer in dogs.

It is an aggressive cancer that causes pain in the affected bone and lameness, and weakens the bone structure making it likely to fracture spontaneously. The tumor frequently spreads to the lungs and also to other bones.

Standard treatment consists of amputation of the affected leg, followed by chemotherapy to prevent or delay the spread of the tumor (metastasis).

Even with this treatment, the majority of dogs still develop metastasis and die from OSA within one year of diagnosis.

When amputation is not an option (for either medical or personal reasons), treatment is directed at decreasing the pain caused by OSA.

Palliative radiation in combination with pain medications provides pain relief in up to 85 percent of dogs. However, these treatments do not usually prevent disease progression and most dogs will succumb to intractable pain or pathological bone fracture within three to five months of diagnosis.

Immune Therapy for the Treatment of Osteosarcoma

Dr. Mason's Osteosarcoma patient The immune system plays an important role in identifying and killing cancer cells in the body.

The Mason lab is currently evaluating a vaccine, called ADXS31-164, that aims to stimulate the body’s immune system to recognize and  kill bone cancer cells.

The vaccine is made from the bacteria Listeria monocytogenes, which has been genetically modified to express a tumor protein (HER-2/neu) that is found in many cancer cells, including canine osteosarcoma.

The bacteria is highly attenuated, which means it has been weakened so as not to cause disease when administered to the patient.

The vaccine is given by intravenous injection and aims to stimulate an immune response against cells that express the tumor protein (HER2/neu).

In this way, it is hoped that the immune system can be trained to recognize both primary and metastatic cancer cells and eliminate them, helping to delay the onset of metastatic disease and in cases where dogs are treated without amputation, prevent primary tumor progression.


Current Osteosarcoma Clinical Trials

OSTEOSARCOMA - Use of a Novel Immunotherapy for Dogs with Bone Cancer of the Leg

Oct 25, 2017

Osteosarcoma (OSA) is an aggressive cancer that frequently arises in the long bones of large-breed dogs. Approximately 90-95% of dogs with osteosarcoma have undetectable metastatic disease at presentation. Despite limb amputation and follow-up chemotherapy, most dogs are euthanized due to progressive metastatic disease within a year of diagnosis.

Dogs enrolled in this clinical trial will receive a HER2-targeting bacterial vaccine after amputation and chemotherapy. This immunotherapy has shown promising results in preventing metastatic disease when evaluated in a small number of dogs with osteosarcoma after surgery and chemotherapy.

Inclusion Criteria:

  • Dogs with newly diagnosed OSA who have received no prior treatment for cancer
  • Dogs with OSA of the leg which is amenable to limb amputation
  • Dogs with no evidence of metastasis at the time of enrollment
  • Dogs weighing at least 25kg (55lbs) after amputation
  • Owners are willing to pursue amputation and chemotherapy at Penn Vet


Dogs will receive three doses of Listeria vaccine at no cost. Each dose is given three weeks apart, starting after standard chemotherapy (carboplatin) is completed. Dogs may have the option to receive booster vaccine every 6-8 months thereafter.

Follow-up chest x-rays will also be covered by the study.

Please note: The study does not cover the cost of standard-of-care amputation and chemotherapy. These are required and must be performed at Penn Vet.

Please contact the VCIC at 215-573-0302 or by email at if you would like more information about this study.

Reference: Mason NJ, Gnanandarajah J, Engiles J, Gray F, Laughlin D, Gaurnier-Hausser A, Wallecha A, Huebner M, Paterson Y. Immunotherapy with a HER2 targeted Listeria induces HER2-specific immunity and demonstrates potential therapeutic effects in a phase I trial in canine osteosarcoma. Clin Cancer Res. 2016 Sep 1;22(17):4380-90

Contact Information:

If you would like more information about this study, please contact the VCIC at:

Mason Cancer Studies Research Sponsor: Advaxis

Preliminary data suggests immune responses induced by ADXS-HER2 might target pulmonary micrometastases and prevent the development of metastatic disease in the dogs that have undergone standard of care amputation and chemotherapy.

Learn more about Advaxis immunotherapies...