Winn Feline Foundation Progress Report
http://www.winnfelinehealth.org/
By Susan Little DVM, Diplomate ABVP (Feline)
June 2002
Recombinant Feline Erythropoietin
Investigators: J.N. MacLeod, J.F. Randolph
College of Veterinary Medicine
Cornell University, Ithaca, NY
Funded 2000, 2001
Anemia is commonly associated with certain diseases in the cat, especially chronic renal failure and some cancers or cancer therapies. A hormone called erythropoietin (EPO) is produced by the kidneys and stimulates the bone marrow to produce new red blood cells to replace old and worn ones in circulation. In diseases such as chronic renal failure, EPO levels may be decreased and anemia may develop as a result. Typical signs associated with anemia are decreased activity and poor appetite.
Recombinant (synthetic) human EPO (rhEPO) has been available for over 10 years and has been used with some success in cats to correct these anemias. But since rhEPO is not identical to feline EPO, some patients eventually produce antibodies against the drug. The antibodies not only prevent EPO therapy from being effective, but also may lead to severe and life-threatening anemia by concurrently binding and removing any residual EPO still being made by the cat's own kidneys.
Dr. James MacLeod's lab at Cornell University has developed a method to produce recombinant feline EPO (rfEPO) in large enough quantities for therapeutic use. Dr. MacLeod's team has already successfully produced recombinant canine EPO and has done clinical trials in dogs. They believe the use of rfEPO will be an effective treatment for EPO-dependant anemias in cats and will not be associated with the same adverse side effects as rhEPO. The rfEPO has already been evaluated for bioactivity in tissue culture and in mice and it has been found to be similar in effectiveness to the currently available rhEPO.
Currenty, trials of rfEPO are being conducted in feline veterinary patients suffering from non-regenerative anemia associated with chronic renal failure. When owners are invited to participate with their cats, they are given full information on the study including its expected benefits and any potential risks. The researchers hope to follow 30 cats with chronic renal failure being treated with rfEPO for one year. During this time, regular bloodwork will help evaluate the effectiveness of the therapy as well as monitor for any adverse effects.
The future availability of rfEPO as a result of this research project may prove to be a safe and effective treatment option for many feline patients suffering from anemia associated with chronic renal failure and some cancers. It is expected to help these patients survive longer and with a better quality of life.
For further reading:
- Cowgill, L., K. James, et al. (1998). Use of recombinant human erythropoietin for management of anemia in dogs and cats with renal failure. J American Vet Medical Assoc. 212(4): 521.
- MacLeod, J., J. Tetreault, et al. (1998). Expression and bioactivity of recombinant canine erythropoietin. American J Vet Research 59(9): 1144.
- Randolph, J., T. Stokol, et al. (1999). Comparison of biological activity and safety of recombinant canine erythropoietin with that of recombinant human erythropoietin in clinically normal dogs. American J Vet Research 60(5): 636.