Differentiating Biosimilars From Generic Drugs

Mohannad Kusti, MD, MPH: I want to speak to the misnomer that biosimilars are the same as generic drugs. That is something I commonly hear from employers. I want to emphasize that biosimilars are not generics. The generics are typically produced by using chemical synthesis, as mentioned earlier, whereas the biologic and the biosimilar go through that complex biological process and synthesis in living tissue and living microorganisms. I also want to mention some terminology that I think is very important to understand. There is something called substitution, which is the practice where the pharmacist may dispense an alternative medication for another without approval of the prescriber. That typically applies to generics, but it doesn’t always apply between biologics and biosimilars. There’s also automatic substitution, where it happens automatically in the system as soon as its prescribed.

The other terminology that I want to mention is switching. Switching is actually the practice where the prescriber decides to exchange one drug with another. That could happen between biologics and biosimilars. But as you can see, it’s different than talking about biosimilars and generic medications.

Then we go into interchangeability as a term that’s defined by statute to mean that the product may be substituted for the reference product without the intervention of the prescribing health provider. Typically, this comes from the FDA, and it requires a lot of studies and a lot of rigorous processes. There’s a similar process in Europe under the European Commission consensus information, and they also define interchangeability as the medical practice of changing one medicine for another that is expected to achieve the same clinical effect in a given clinical setting, and in any patient on the initiative or with agreement with the prescriber.

When we’re talking about biosimilars and generic medications, obviously there is a huge difference between the ability to have the substitution, the switching, and the interchangeability.

The FDA approval pathway for biologics and biosimilars is a little bit different than other medications. It does require extensive clinical studies, including phase 1, 2, and 3 clinical trials, and it also requires periodic safety updates from the manufacturers and journal literature to evaluate the safety and effectiveness of both biologics and biosimilars.