Biosimilars are treatments that mimic the active ingredients of biologics, a class of drugs that include gene therapies, stem-cell therapies, monoclonal antibodies, and insulin. As the patents of these drugs expire, biosimilars can step into the field by mimicking a reference biologic.
Biosimilars are not exact replicas of biologics, as biologics are highly complex molecules that are grown instead of synthesized, providing them with micro-variability. This variability makes it so that biosimilars cannot be exact copies.
Along these same lines, generic drugs and biosimilars are not the same, as generic versions use an identical active ingredient. In contrast, biosimilars have active ingredients with the same mechanism of action and expected benefits and risks, even if they are not identical.
Still, like other drugs, biosimilars must follow standards set by the U.S. Food and Drug Administration (FDA), such as being similar to the reference biologic in both its structure and function.