An Introduction to Biosimilars

I first heard the word ‘biosimilar’ in 2009 at a conference in Rome. Perhaps the easiest way to think about these agents is that they are essentially the generic versions of biologic agents. The European Union (EU) has been way ahead of the U.S. in regulating these agents; the process for approving biosimilars in Europe was established in 2003 and central, and not national, approval by the European Medicines Agency (EMA) is required. EMA first developed guidelines for the approval of biosimilars via an abbreviated registration process in 2005-2006.

In 2006, omnitrope (somatropin) was the first product approved in the EU as a biosimilar. The EMA has approved 22 biosimilars within the product classes of human growth hormone, granulocyte colony-stimulating factor, erythropoietin, insulin, and TNF-inhibitor. Two biosimilar approvals have been withdrawn; one for filgrastim in April 2011 and one for somatropin in May 2012, leaving a total of 20 biosimilars approved for use in Europe.

The Affordable Care Act of 2010 created an abbreviated licensure pathway in the U.S. for biological products that are demonstrated to be “biosimilar” to or “interchangeable” with an FDA-licensed biological product. Biosimilarity means that the biological product is highly similar to the U.S.-licensed reference biological product and there are no clinically meaningful differences between the biologic product and the reference product in terms of the safety, purity, and potency of the product. Interchangeability means that the biologic product is biosimilar to the U.S.-licensed reference biological product and can be expected to produce the same clinical result as the reference product in any given patient. For a biological product that is administered more than once to an individual, the risk in terms of safety or diminished efficacy of alternating or switching between use of the biological product and the reference product will not be greater than the risk of using the reference product without such alternation or switch. Interchangeable biological products may be substituted at the pharmacy level without the intervention of a healthcare provider.