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.