To further assess the safety profile of epoetin-ζ, including the risk of epoetin-associated PRCA, when using a different route of administration (SC rather than IV injection), the PASCO II study (post-authorization safety cohort observation of Retacrit and Silapo (epoetin-ζ) administered subcutaneously for the treatment of renal anemia) was designed. Here, EPO is linked to pure red-cell aplasia.