epoetin alfa

Endogenous EPO is produced by peritubular interstitial fibroblasts in the renal cortex in response to hypoxia (via HIF-1α stabilization) and stimulates erythroid progenitors in the bone marrow. Recombinant EPO (epoetin alfa, darbepoetin alfa — longer half-life) is used for anemia of CKD (the prototypical indication), chemotherapy-induced anemia, zidovudine-induced anemia in HIV, and to reduce transfusion needs in some surgical patients. Adverse effects: hypertension (often dose-related), thromboembolic events, increased mortality and tumor progression in cancer patients when targeting hemoglobin >11–12 g/dL — hence the FDA black-box warning and target Hb 10–11 g/dL. Iron deficiency must be corrected first or epoetin will not work. Abused by endurance athletes for blood doping; detection drove development of biomarker testing.