Comments on the FDA's Biosimilar Interchangeability Draft Guidance Highlight a Growing Need for Clarity

Jackie Syrop

The comment period for the FDA’s Draft Guidance Considerations in Demonstrating Interchangeability With a Reference Product (Docket FDA-2017-D-0154) ended on May 19, 2017. The 52 comments were submitted by manufacturers of biologics and biosimilars, third-party payers, pharmacy trade associations, and patient groups.

While most commenters congratulated the FDA on its flexible approach to interchangeability, many called on the agency to provide additional details about requirements for switching studies, the distinction between interchangeability and biosimilarity, guidelines for the use of foreign reference drugs in switching studies, and the requirements for showing interchangeability among all indications and all presentations. Commenters raised questions about what interchangeability truly means, and asked whether interchangeability should be interpreted as a higher standard or simply as an additional data requirement.

The FDA’s draft guidance called on biosimilar manufacturers to use so-called switching studies to determine the safety and efficacy of a biosimilar with respect to its reference product. Such studies would require that the comparator product should not be used as a control only, but should instead be used in both the active (switching) arm and the control (non-switching) arm of switching studies.

Furthermore, the guidance notes that using a non-US-licensed comparator product would not generally be appropriate. In its commentary, Pfizer disagreed with that recommendation, saying that such a practice has the potential to create practical challenges regarding where a switching study could be conducted; the Biosimilars Forum also said this aspect of the guidance could undermine the global nature of biosimilar development.

Many commenters expressed concern over whether the FDA will use labeling, nonproprietary naming, or another naming method that would indicate that a biosimilar is interchangeable. For example, the Hematology/Oncology Pharmacy Association (HOPA) said, “Considering that there may be differences in the criteria used to approve the drug, differences in approved indications, and differences in immunogenicity, it is important to have a name that allows providers to differentiate which drug they are actually using, or switching to.” HOPA underscored its previous recommendation that the drug name consist of the reference drug’s International Nonproprietary Name (INN) plus a meaningful suffix, and said the current FDA position of using an INN plus a random suffix is both confusing and unsafe.

Some commenters asked the FDA to explain its plan for post-marketing changes to reference drugs after findings of interchangeability. Commenters also requested greater clarity and clearer direction from the FDA regarding interchangeability and multiple applications, given the abbreviated process for generic drug approvals and continuing confusion about the language of the Biologics Price Competition and Innovations Act [BPCIA], a legal quandary that has made its way to the Supreme Court for clarification).

AARP, Inc, which represents 38 million Americans over age 50, also weighed in, saying that the biosimilar approval pathway will only be fully utilized if the requirements for biosimilar approval are reduced relative to requirements for a traditional biologic license application. “If not,” says the organization, “companies could forgo biosimilar development entirely. Given manufacturers’ clear and growing interest in developing biologic drugs, it is difficult to overstate how much this outcome would negatively affect patients, payers, and taxpayers.” AARP’s overriding concern is that the BPCIA be implemented in a manner that ensures safety and efficacy without creating unnecessary barriers to the savings promised by the biosimilar approval pathway.