Food and Drug Administration (FDA) officials have published an article in the New England Journal of Medicine (NEJM) that discusses some of the issues facing the agency in establishing a regulatory framework under the Biologics Price Competition and Innovation Act of 2009 for the approval of biologic drugs that are “biosimilar” to already-approved products. Titled “Developing the Nation’s Biosimilars Program,” the August 4, 2011, article indicates that the agency is considering what scientific criteria will best address a key question for the U.S. biosimilars program: “how similar is similar enough when it comes to the substitution of complex biologic drug products in clinical practice?”

FDA is apparently turning to its experience with biologics and to lessons provided by the European Medicines Agency “which published general guidelines on biosimilars in 2005 and approved its first biosimilar in 2006.” Citing a “totality of the evidence” approach, the article discusses the challenges it poses, how FDA will interact with biosimilar sponsors and what risk-based factors must be considered. The authors also address the new law’s “interchangeability” standard, under which “[a] biologic will be considered interchangeable with a reference product if the developer demonstrates that it can be expected to produce the same clinical result in any given patient and that the risk associated with alternating or switching between the two products is not greater than that involved in continuing to use the reference product.” Pharmacists can substitute interchangeable biologics without a presciber’s intervention.