What is a biologic?
Most traditional prescription medications (also known as small-molecule drugs) are manufactured through chemical processes. Biological products, however, are generally large, complex molecules made from living cells. Biologics can be used to treat cancer, rheumatoid arthritis, inflammatory bowel disease, multiple sclerosis, psoriasis, diabetes, and other conditions.
Therapeutic proteins; monoclonal antibodies; blood, blood components, and their derivatives; allergenic products; and vaccines are examples of biological products. Because biologics are so different from small-molecule drugs, particularly in their manufacturing, the Food and Drug Administration (FDA) has a separate process for reviewing and approving them.
It takes months to manufacture a biologic drug, and every part of the process must be carefully monitored and controlled. Even small changes in the manufacturing process or environment (e.g., temperature changes) can make a big difference in the final product. Because biologics are so complex to develop and manufacture, they are often very expensive.
What is a biosimilar?
Generic medicines are essentially identical copies of brand name drugs. Unlike generic drugs, however, it is impossible to make an exact copy of a biologic. In fact, all biologic medicines vary slightly from one batch to another because they are derived from living cells, which constantly undergo change.
Instead, biosimilars are characterized as highly similar to an FDA-approved biologic, which may also be known as a reference product in this context. While not an exact match, a biosimilar is a biological product that is highly similar to and has no clinically meaningful differences from an existing FDA-approved biological reference product.
FDA may approve more than one biosimilar product for a single reference product. The agency approved the first biosimilar in 2015. Click here to see the latest list of FDA-approved biosimilars.
Pharmacists can find information about all FDA-licensed biologic medications, FDA-licensed biosimilars, and their interchangeability in the agency’s Purple Book database. The database also contains information about all FDA-licensed allergenic, cellular and gene therapy, hematologic, and vaccine products that the agency regulates.