Lymphoma is one of the most common cancers found in dogs, with a survival rate of 0 to 2 percent under current treatment methods. These poor statistics have researchers constantly looking for better ways to increase diagnosed dogs’ lifespan.
Steven Suter, VMD, MS, Ph.D., Dipl. ACVIM, is performing bone marrow transplants using a leukapheresis machine to harvest healthy progenitor cells from a canine patient’s blood.
“With this method, the dog receives standard chemotherapy drugs, often referred to as CHOP,” says Dr. Suter, assistant professor of medical oncology at North Carolina State University’s College of Veterinary Medicine. “Once in clinical remission, which means the dogs lymph nodes are of normal size, a high dose of Cytoxan (cyclophosphamide) is given to clear as much cancer as possible from the dog’s blood. About 10 days later, it is then given Neupogen (filgrastim), which costs about $2,000 per patient. This drug increases the dog’s white blood cell count and also drives stem cells, called CD34+ progenitor cells, out of the bone marrow and into the peripheral blood.”
After six days of Neupogen, the dog is mildly sedated and connected to the leukapheresis machine, which harvests the CD34+ progenitor cells from the blood over about five hours. The progenitor cells are then counted and stored in a refrigerator overnight.
The next day, the dog is given total body radiation, which is lethal to 95 percent of dogs who don’t receive a bone marrow transplant. The harvested CD34+ progenitor cells are then returned to the dog’s body via a simple IV infusion.
This procedure is called an autologous peripheral blood stem-cell transplant.
“Traditional methods of harvesting CD34+ progenitor cells from the bone marrow are invasive and extremely painful,” Suter says.
“There is also bruising and an increased chance of infection. Using the leukaphoresis machine completely eliminates these issues since there are virtually no side effects from the harvesting procedure. However, the dogs do get gastrointestinal upset from radiation treatment.”
Suter has treated 15 dogs using this method, and all patients have left the hospital after successfully undergoing the treatment.
“Two dogs relapsed with lymphoma two and a half months after the procedure,” Suter says. “Two other dogs died from non-lymphoma causes within nine months of the transplant. Finally, one dog left our hospital with close to normal blood counts and then died approximately three weeks after the transplant. I’m expecting that we’ll eventually see a 30 to 66 percent long-term survival rate in the transplanted dogs, which is what the long-term survival rate in people is.”
The NCSU bone marrow transplant unit has been operating since October 2008.
A new leukapheresis machine costs about $85,000 and the client cost is $13,000 to $15,000. Donations have been given by individual donors, No companies have done so.
This technique has been performed on dogs since the 1970s, when the procedure was being developed for use in humans, Suter says. At that time, the long-term survival rate for the canine patients was about 30 percent. This is the first time the procedure is being performed in a clinical academic setting to treat client-owned dogs.