Interchangeability and Biologics, Biosimilars, and Generics

As of this publication in 2023, there are over 20,000 FDA-approved prescription drugs, more than 32,000 generic drugs, 671 FDA-licensed biologics, and 35 FDA-approved biosimilars. When recommending a treatment option between a biologic, biosimilar, or generic, what’s the difference?

Background
Biosimilars are available for the treatment and management of diabetes. Figure 1 highlights the key differences between biologics, biosimilars, and generics. Briefly, biologics encompass a wide variety of products that are typically living and naturally sourced. Examples include vaccines, recombinant proteins, gene therapies, and more. Biosimilars are products that are like the reference biologic with their origin, therapeutic target, efficacy, safety, adverse event profile, purity, and potency but are just slightly different. Comparatively, biologics and biosimilars are much larger in size than generics and are much more costly. Suffice it to say, a biosimilar is not a generic.

Generic medications are smaller, chemically synthesized molecules, and are typically more cost-effective compared to the brand reference. The generic drug must use the same active ingredient, strength, dosage form, and route of administration as the brand product. All products go through a rigorous approval process, requiring demonstration of the same pharmacokinetics and pharmacodynamics as the originator reference product.

Interchangeability
With the ever-changing landscape of treatments, there are biosimilars for diabetes, inflammatory conditions, and cancers. That said more clarity on switching a patient from a biologic to its interchangeable biosimilar is warranted. Here are a few key considerations when thinking about that switch.

• Definitions and Legalities
  • Not all biosimilars are interchangeable. An interchangeable biosimilar must be requested by the Sponsor, which requires additional criteria to be met before receiving the “interchangeable” designation from the FDA.
  • Pharmacy-level substitutions may be performed just as with brand and generic switches depending on state pharmacy laws.
• Patient-related Factors
  • Biosimilars aren’t always cheaper for the patient due to factors like insurance.
  • Sensitivities to changes in medications can affect more than others.
  • Previous medical and medication history may determine if a patient is a good candidate for an interchangeable biosimilar, including ongoing monitoring and follow-up efforts.

The use of biosimilars is a complex issue. Increased comfort to switch or not to switch comes with the increased familiarity of biosimilars. Efforts to characterize the long-term safety and efficacy of switching between biologics and biosimilars are ongoing. Biosimilars have the potential to improve access and affordability to novel therapeutics and with careful consideration, finding the right treatment for the right patient is possible to improve patient outcomes.

Figure 1. Differentiation between biologics, biosimilars, and generics.

REFERENCES

1. Terrie YC. Fostering the Adoption of Biosimilars Into Clinical Practice. U.S. Pharmacist. Published June 16, 2023. Accessed September 1, 2023. https://www.uspharmacist.com/article/fostering-the-adoption-of-biosimilars-into-clinical-practice

2.  Food and Drug Administration. FDA at a Glance. Published April 2023. Accessed September 1, 2023. https://www.fda.gov/about-fda/economics-staff/fda-glance

3.  Food and Drug Administration. Novel Drug Approvals for 2023.

4.  Food and Drug Administration. Office of Generic Drugs 2022 Annual Report. Generic Drugs. Published March 1, 2023. Accessed September 1, 2023. https://www.fda.gov/drugs/generic-drugs/office-generic-drugs-2022-annual-report

5.  Mahakkanukrauh A, Chaiamnuay S, Koolvisoot A, et al. Safety and effectiveness of intravenous CT-P13 in inflammatory arthritis: post-marketing surveillance study in Thailand. Immunotherapy. 2023;15(14):1143-1155. doi:10.2217/imt-2022-0290