For those of us who are ready to see significant relief in the biosimilar regulatory process, the Biden Administration’s 2025 budget proposal promises an important step. If this line item in the budget proposal remains untouched, the interchangeability designation will be relegated to history. The President’s budget proposal would “permit biosimilar substitution without FDA determination of interchangeability.”
Using the FDA’s own terminology, the “totality of evidence” (science and real-world experience) unequivocally supports that any approved biosimilar may be switched in place of the reference product. The clinical equivalence of these products is undeniable at this point.
The biosimilar interchangeability designation has been further complicated by the FDA in that the agency has ruled that specific biosimilars covered under the medical benefit may also be considered interchangeable with the reference product. Outside of a specialty pharmacy “white bagging” a provider-administered biologic, this designation has no relevance to its intended purpose: to permit automatic substitution at the pharmacy. The amount (and type) of data needed to obtain the designation is variable. Furthermore, the applicability of interchangeability to high-concentration or low-concentration formulations of adalimumab have contributed uncertainty and confusion among manufacturers, pharmacists, payers, and prescribers. Even more confounding has been FDA’s difficulty in defining when the 12-month period of exclusivity begins for an interchangeable biosimilar.
Legislative proposals have been introduced to eliminate the designation. Now, the Biden Administration seems determined to get on board.
According to the Department of Health and Human Services’ explanation, “The statutory distinction between biosimilars and interchangeable biosimilars has led to confusion and misunderstanding, including among patients and healthcare providers, about the safety and effectiveness of biosimilars and about whether interchangeable biosimilars are safer or more effective than other biosimilars. This proposal would amend section 351 of the Public Health Service Act to no longer include a separate statutory standard for a determination of interchangeability and to deem all approved biosimilars to be interchangeable with their respective reference products. This change makes the U.S. biosimilar program more consistent with current scientific understanding as well as with the approach adopted by other major regulatory jurisdictions such as the European Union where biosimilars are interchangeable with their respective reference products upon approval. Permitting biosimilar substitution in this way is expected to increase uptake of safe and affordable biosimilars, with potential downstream effects of increasing competition, and access.”
Going a step beyond the Biden Administration’s statement, I believe that any biosimilar in the same drug category is substitutable for any other as both a clinical and practical reality. Yes, the Law of Transitivity does work for biosimilars.
Will this line item survive the approval process? The Office of Management and Budget forecasts no increase (or decrease) in spending for this line item, which may help it slip through. We’re hoping for the beginning of the end of this statutory definition.
