Amgen’s Epogen (epoetin alfa) and Aranesp (darbepoetin alfa) are blockbuster erythropoiesis-stimulating agents (ESAs). ESAs are approved for the treatment of anemia resulting from chemotherapy, chronic kidney disease, and human immunodeficiency virus (HIV), and also to reduce the number of blood transfusions during and after major surgeries. Erythropoietin is a protein that stimulates the bone marrow to make oxygen-carrying red blood cells (RBCs), and recombinant erythropoietin works in the same way as human erythropoietin.
Epogen was FDA-approved in 1989, and Aranesp followed in 2001. The clinical studies that allowed for the approval of ESAs showed that these agents led to a shorter overall survival and/or increased risk of progression or recurrence in patients with breast cancer, non-small cell lung cancer, head and neck cancer, lymphoid cancer, and cervical cancers. Given such results, in 2010, the FDA mandated the need for a Risk Evaluation and Mitigation Strategy (REMS) for each patient prior to administration of ESAs for anemia due to chemotherapy, to ensure that the benefits of the agents outweighed the risks. ESAs provide the only therapeutic alternative to RBC transfusions in cancer patients with anemia due to chemotherapy, and without them it has been estimated that twice as many patients receiving chemotherapy would require RBC transfusions.
Amgen submitted data from 2006 to 2014, which showed a decrease in the number of patients receiving chemotherapy who warranted ESAs, and that those who received ESAs started at an appropriate dose level. Overall, data from surveys showed that prescribers were aware of the risks associated with the agents, and that they were being used appropriately. This led the FDA to announce, in April 2017, that REMS were no longer necessary to ensure the benefits outweigh the risks of ESAs. This, however, does not change the fact that these agents do pose a risk. Instead, it demonstrates that the FDA believes that physicians understand the risks posed, without requiring a REMS.
The decision to remove the REMS marks the end of an era for the FDA, ending one of the largest programs put in place by the agency following the 2007 FDA Amendments Act, which, among various other provisions, enhanced the agency’s authorities regarding postmarket safety of drugs. The agency’s use of REMS has declined significantly in recent years, and it appears as if the FDA is undoing some of its key actions from its ‘drug safety’ era of a decade ago. For example, the agency removed the requirement for REMS for antidiabetic drug Avandia (rosiglitazone) in December 2015.
The ruling will help advance the use of biosimilars in the US, removing a potential obstacle for their use. The REMS especially presented hospitals with complications and difficulties when dealing with patients who had more than one indication for an ESA. The FDA ruling came a month before the Oncologic Drugs Advisory Committee recommended approval of an epoetin alfa biosimilar by Pfizer. Surprisingly, this biosimilar was then rejected in June 2017, although this was due to concerns regarding Pfizer’s fill-finish plant in Kansas, which was listed as the potential manufacturing site in the Biologics License Application (BLA), rather than concerns with the molecule itself. Thus, it is likely that Pfizer will re-submit a BLA in the near future. Novartis is also aiming to bring an Epogen biosimilar to the US market; biosimilars are already marketed in the EU and Japan.