Still in clinical trials I believe....found this info at one vet listed under "clinical trials":
ARATANA AND SAGE
We’re conducting a clinical study for dogs with osteosarcoma who have undergone amputation and chemotherapy. There are eligibility requirements for your dog to participate in the study for the conditionally licensed Canine Osteosarcoma Vaccine, Live Listeria Vector and your veterinarian will review your dog’s medical history, perform a physical exam, take thoracic radiographs, and submit routine blood and urine tests. If you would like to learn more, please contact SAGE Centers at aratanatrial@sagecenters.com for more information.