Biosimilars: Policy, clinical, and regulatory considerations

Purpose. The regulatory background surrounding biosimilars (biopharmaceuticals that are considered similar in composition to an innovator product, but not necessarily clinically interchangeable); equivalence, interchangeability, and unique considerations associated With biopharmaceuticals; the biopharmaceutical protein production process; scientific facts for use in the policy discussion about biosimilars; the European Union system for biosimilars; and the current status of biosimilars legislation in the United States are described. Summary. An abbreviated regulatory pathway for the approval of biosimilars, and a process for safely demonstrating the therapeutic interchangeability of these proteins, has the potential to provide meaningful cost savings. This economic advantage to patients can translate into important public health benefits. But to date, no formal regulatory process exists in the United States for bringing these drugs to market. In addition, the current tools for fully characterizing biopharmaceuticals are not-in certain cases well developed, especially for proteins that have complex structures or are heavily glycosylated. In addition, using "similar" but not completely "identical" proteins interchangeably raises concerns about potentiating immunogenicity. The bottom line is that demonstrating therapeutic equivalence and interchangeability for biosimilars is not a straightforward matter-it cannot be based on the same criteria as for conventional small-molecule drugs. The science, while obtainable, is more complex. For example, it is assumed that showing that a biosimilar protein can be safely used interchangeably with an innovator protein would require, at the least, some limited clinical data and interchangeability studies. Notwithstanding the more complex scientific and clinical issues particular to protein products, most believe that a process for enabling the approval of safe and effective biosimilar proteins is not only possible, but an important public health goal. The European Union system for biosimilars may provide a model for anticipating and resolving the scientific and policy issues related to biosimilars in the U.S. However, biosimilars legislation is unlikely to be passed before the 2008 presidential election. Conclusion. The legal and regulatory status of biosimilars remains to be resolved in the United States as policy makers address the scientific and policy issues surrounding product manufacturing, patent terms, and clinical use.