Biosimilars the generic versions of biological drugs are considerably more difficult to produce than regular drugs. Now, a new draft guidance issued last week by the FDA aims to more precisely define the steps biopharmaceutical companies must follow to navigate the approval process and to delineate the quality standards for reproducing such medications. Although the Affordable Care Act specified that the FDA must issue such a guidance, no company has yet applied for approval.
While standard drugs are generally small molecules that can be uniformly reproduced by any given manufacturer, biosimilar drugs cannot be so exactly replicated. These drugs are usually larger, more complex compounds that must undergo an extensive manufacturing process one that will undoubtedly create some variation among the final products.
That biological drugs are so susceptible to variation makes it especially important to ensure that generic companies are making a version of the drug that is sufficiently similar to the approved brand-name product. ACSH's Dr. Josh Bloom explains: Conventional drugs, like Lipitor, are single compounds that are generally easy to manufacture, purify, and analyze. Using sound manufacturing practices, a generic will be much the same as the brand name version. But biological drugs are complex mixtures that require a recipe-like manufacturing process. There is batch-to-batch variability even within the same company but when someone else tries the recipe, the product can turn out quite differently. And purification and analysis of these drugs are much harder. In the absence of tight controls, substandard biosimilars could do considerable damage.