Nowadays almost all commercially available erythropoietin represents a product of recombinant DNA technology (rhEPO). Since there were different laboratories working on the problem of EPO production, today we have several types of EPO.
In most cases, their amino-acid sequence is identical to natural hormone and their major difference is in the pattern of glycosylation. As we mentioned above they may differ in purity, stability and strength of biological activity.
Since 1988 EPO alfa and EPO beta have been used as major drugs for induction of erythropoiesis. When used subcutaneously, their bioavailability is about 25%. Their maximum concentration in the blood occurs in 12-18 hours after administration.The half-life – up to 24 hours (in case of intravenous administration – 5-6 hours).
Darbepoetin alfa or novel erythropoiesis stimulating protein (NESP) has been used for the past few years. Due to additional sites of glycosylation and some changes in amino-acid sequence, its half-life is 3-times longer as compared to epoetin alpha and epoetin beta.
EPO theta is probably the most effective and least allergenic among EPO family. It is produced in the culture of human cells and has only 99% identity to human hormone.
EPO omegahas biggest difference from human erythropoietin, therefore it is easy to detect it in a doping tests.
One should pay special attention to the new erythropoietin of third generation, which carry the name Mircera (methoxy polyethylene glycol-epoetin beta). This EPO has extremely long half-life, which is 6 times longer as compared to darbepoetin-alpha and about 20 times longer than EPO alpha, which creates the possibility of long breaks between drug injections.