Yesterday, Pfizer announced that FDA had approved Retacrit® (epoetin alfa-epbx), a biosimilar of Amgen’s Epogen® and Johnson & Johnson’s Procrit® (epoetin alfa).  Epoetin alfa (EPO) is a blockbuster treatment for anemia.  Retacrit is the first EPO biosimilar approved in the United States. EPO biosimilars have been marketed in the EU for over a decade.   Hospira (now a Pfizer company) initially filed an application for approval of its EPO biosimilar in 2014.  FDA rejected that application in a complete response later and Hospira later resubmitted it after addressing FDA's concerns. While Retacrit received a favorable FDA advisory committee recommendation in May 2017, it was rejected again in a second complete response letter due to concerns with the proposed manufacturing site for the biosimilar.  Nearly a year later, FDA approved Retacrit.  Pfizer plans to launch Retacrit this year.