Biosimilars in Oncology in the United States: A Review.

Importance: Biosimilars are biological medicines that contain a highly similar version of the active substance of an already approved biologic reference product. The availability of biosimilars might provide an opportunity to lower health care expenditures as a result of the inherent price competition with their reference product. Understanding how biosimilar cancer drugs are regulated, approved, and paid for, as well as their impact in a value-based care environment, is essential for physicians and other stakeholders in oncology.

Observations: Important structural and regulatory differences exist between biosimilar and generic medications. Minor differences in clinically inactive components with no clinically meaningful differences between biosimilars and their reference biologic are allowed. A biosimilar uses the same mechanism of action as the reference biologic, and its condition of use is the same as the approved indication, although extrapolation is permitted across indications under regulatory guidance. A biosimilar has to have a similar route of administration, dosage, and strength as the reference biologic. As patent expiration of multiple cancer biologics will occur in the next few years, more biosimilars might enter the market. Whether the approval and use of biosmilars as replacements for these heavily prescribed reference biologics will ultimately lead to cost savings is unknown and requires longer follow-up. Two biosimilars with an oncology supportive care indication are currently approved in the United States; both are myeloid growth factors.

Conclusions and Relevance: The financial impact of generic drug competition can be dramatic, but significant differences in regulatory and development processes between generics and biosimilars limit such comparisons and likely present significant challenges for biosimilar approval and adoption in the US market. However, a value-based care environment and their cost-savings potential make biosimilars an attractive option for the therapeutic arsenal. Oncologists' understanding of biosimilars is critical to moving forward.