Doping with recombinant human erythropoietin (rHuEPO) engineered in Chinese hamster ovary (CHO) cell cultures (Epoetins alfa and beta) or its hyperglycosylated analogue (Darbepoetin alfa) is detectable by isoelectric focusing of urine samples, because the glycans of the drugs differ from those of endogenous EPO. However, detection will become more difficult as several novel erythropoietic drugs are to come on market. These include biosimilars of Epoetin alfa, pegylated Epoetin beta (CERA), rHuEPO produced in baby hamster kidney (BHK) cells (Epoetin omega), gene-activated EPO (Epoetin delta, DynepoTM) from human fibrosarcoma cells (HT-1080), EPO fusion proteins and peptidic (HematideTM) as well as non-peptidic EPO mimetics. Furthermore, small orally active drugs capable of stimulating endogenous EPO production have been developed. These include stabilizers of hypoxia-inducible transcription factors (HIF) that bind to the EPO enhancer, and GATA inhibitors which prevent GATA from suppressing the EPO promoter. Because EPO signalling involves protein tyrosine phosphorylation, inhibitors of hemopoietic cell phosphatase (HCP) are also under study to stimulate erythropoiesis.

In conclusion, both novel erythropoietic peptides and orally active compounds will be available ? not only for therapeutic benefits ??but also for misuse in endurance sports. It is crucial to inform the athletes and their supporting staff of potential health risks.