On July 28, 2021, the Food and Drug Administration (FDA) approved the first interchangeable biosimilar product, Semglee (insulin glargine-yfgn), as a diabetes treatment. Semglee is both biosimilar to and interchangeable with Lantus (insulin glargine), a long-acting insulin analog.

When the Biologics Price Competition and Innovation Act (BPCIA) was enacted in 2010, it granted the FDA the power to approve biologics that are demonstrated as biosimilar to FDA-approved reference products. It also made possible an “interchangeability” designation for biosimilar products that meet additional requirements. In January 2017, the FDA published Draft Guidance titled “Considerations in Demonstrating Interchangeability With a Reference Product.” The Final Guidance was issued in May 2019. Semglee’s 2021 approval is the first biosimilar and interchangeable product approval made by the FDA.

A biosimilar is a biological product that is highly similar to and has no clinically meaningful differences from an existing FDA-approved reference product. An interchangeable product, in addition to being biosimilar, meets additional requirements based on further evaluation and testing of the product (Section 351(k)(4) of the Public Health Service Act (PHS Act)). A manufacturer of a proposed interchangeable product will need to provide additional information to show that an interchangeable product “can be expected to produce the same clinical result as the reference product in any given patient.” See Section 351(k)(4)(A) of the PHS Act. Also, “for a biological product that is administered more than once to an individual, the risk in terms of safety or diminished efficacy of alternating or switching between use of the biological product and the reference product is not greater than the risk of using the reference product without such alternation or switch.” See Section 351(k)(4)(B) of the PHS Act.

Unlike a biosimilar product, an interchangeable product may be substituted for the reference product without the involvement of the prescriber. This substitution may occur at the pharmacy, much like with generic drugs, subject to state pharmacy laws.

The FDA expects to approve more interchangeable biosimilar products in the future.