The Science Behind Biosimilars

Many additional biosimilars of reference products with indications for both rheumatologic and nonrheumatologic diseases are under development.

The white paper discusses in detail the:

• Regulatory pathways for approval;
• Immunogenicity and scientific aspects of manufacturing;
• Extrapolation of indications, switching and substitution, and interchangeability; and
• Economics of biosimilars and patient access.

For all biosimilars, regulatory agencies expect that clinical trials will include a single crossover from the reference product to the proposed biosimilar, to assess whether this transition induces antidrug antibody formation with a resultant loss of efficacy. If a biosimilar is intended for long-term administration, as is the case for rheumatologic indications, the white paper authors recommend that immunogenicity data be acquired over at least one year.

An important implication of the comparative immunogenicity studies carried out to date is that a patient who develops antibodies to a reference drug with resultant loss of clinical response should not be switched to its biosimilar.

Although none of the biosimilars approved to treat rheumatologic and other inflammatory diseases has been studied in children, several have been approved for pediatric indications by extrapolation.

The authors state that postmarketing surveillance of biosimilars should be conducted in children and adolescents, as well as in adults.

Insurance companies and PBMs will continue to play key roles in determining the economic impact of biosimilars, according to the authors. Even under ideal circumstances, it will likely take several years for overall savings to the U.S. health system from the use of biosimilars to be realized.

The white paper concludes: “it is reassuring to recognize the scientific rigor with which the FDA and other regulatory agencies around the world have evaluated biosimilars. Healthcare providers should now incorporate biosimilars, where appropriate, into regimens to treat patients with rheumatologic diseases. It is important to maintain a working knowledge of approved biosimilars and to monitor evolving policies and guidelines regarding the development and use of new biosimilars. …

“Communication between providers, pharmacists and patients will be critical to alleviate anxiety and reduce skepticism regarding the use of these newly available agents. We remain optimistic that the use of biosimilars will improve patient access to biologic agents, allowing continued delivery of high-quality healthcare to be realized at a lower cost to the individual patient.”