Erythropoietin is renal hormone that controls the feline bone marrow's production of red blood cells. In chronic renal disease, erythropoietin production is reduced and anaemia results.
Synthetic EPO and erythrocyte-stimulating agents (ESAs), such as epoetin alfa, epoetin beta and darbepoetin alfa, have been developed to counteract the effects of decreased erythropoietin production and anaemia in cats. The use of ESAs has been associated with a number of complications, such as iron deficiency, hypertension, arthralgia, fever, seizures, polycythemia and pure red cell aplasia (PRCA). Darbepoetin has a prolonged half-life compared with epoetin and thus can be given only once a week, instead of three times a week.
Erythropoietin (EPO) will cause rapid correction of non-regenerative anaemia by stimulating marrow progenitor cells. EPO is indicated in chronic renal disease in cats. Because r-HuEPO administration is not without risk, its use in companion animals should be limited to cases in which anemia significantly affects quality of life. In many cats, this happens when the hematocrit level falls below 20%.
Human recombinant erythropoietin (r-HuEPO) has become a common treatment choice for anemic patients with chronic renal disease. It is a genetically engineered protein that contains 165 amino acids. The administered product consists of r-HuEPO in 0.25% human serum albumin buffered by sodium citrate and sodium chloride. The erythropoietin molecule is generally similar among species, allowing for cross-species biologic activity. r-HuEPO is not currently licensed for use in companion animals, so its use in veterinary patients is strictly extralabel. Although the most common indication for r-HuEPO is anemia associated with renal insufficiency, its use has also been studied for other causes of nonregenerative anemia, with varying results. The use of r-HuEPO in cases of feline nonregenerative anemia unrelated to renal insufficiency needs further examination.
Consider using EPO when PCV is <20%: dose with 75-100 U/kg SQ three times per week until PCV is low normal (35%), then reduce dose and frequency to 50-75 U/kg SQ two times per week. It is important to monitor PCV and blood pressure, due to the direct vasoactive effects of EPO, every two weeks for the first 60-90 days to detect development of anti-EPO antibodies should they occur. If they do, cease EPO immediately. The cat may be transfusion-dependant for 2-4 months until antibody levels decrease. It is also important to administer iron at the start of the regime and until appetite is good. While there is a risk of antibodies to EPO developing, the majority of cats will enjoy the benefits of an improved hemogram.
- Chalhoub S et al (2011) Anemia of renal disease: what it is, what to do and what's new. J Feline Med Surg 13(9):629-640
- Cowgill, LD (1992) Application of recombinant human erythropoietin in dogs and cats. In: Bonagura JD, Kirk RW, eds. Kirk's Current Veterinary Therapy XI: Small Animal Practice. Philadelphia: WB Saunders; pp:484-487
- Bowen D, Culligan D, Jacobs A. (1991) The treatment of anemia in the myelodysplastic syndromes with recombinant human erythropoietin. Br J Haematol 77:419-423