By Michael Reilly, Executive Director, Alliance for Safe Biologic Medicines (ASBM)

In a recent CBS News interview, newly appointed FDA Commissioner Dr. Marty Makary called for more robust clinical evidence before recommending the latest COVID-19 booster shots. “There’s a void of data,” Dr. Makary said, underscoring a renewed focus on restoring public trust through a commitment to rigorous, evidence-based evaluation. 

This same data-first mindset is needed in discussions around biosimilars, especially interchangeable biosimilars—the only biosimilars that can be substituted by third parties such as insurers or pharmacy benefit managers (PBMs) without physician involvement.

Any efforts to weaken or eliminate data requirements for biosimilars or interchangeable biosimilars jeopardize the hard-earned confidence physicians and patients have developed in these products. The FDA recently updated its guidance to allow sponsors to avoid providing supplemental data to support a claim of interchangeability in some cases. Because they are created by living cells, biologics cannot simply be copied and Congress appropriately created a separate regulatory framework, distinct from generic drugs. Any proposal to deem all biosimilars interchangeable- removing the additional data requirements that give interchangeable biosimilars their credibility and clinician trust is a back door to deeming biosimilars generic drugs.

This is a dangerous direction for patients concerned about maintaining treatment stability- and it’s not supported by U.S. physicians.

At an April 8th House Health Subcommittee hearing on biosimilars, Dr. Edward Edgerton, a practicing rheumatologist with the American College of Rheumatology (ACR), emphasized the importance of the current FDA standard to physician confidence:

“ACR strongly supports the rigorous pathway for interchangeability approved by the FDA in 2019. The FDA must ensure that biosimilars and interchangeable biosimilars are safe and effective. The ACR recognizes increasing cost pressures may cause payers to push patients toward biosimilars. This is most appropriate when there is data available.”

At the same hearing, Dr. Aaron Kesselheim, a Harvard Medical School professor affirmed that trust in biosimilars cannot be assumed, and that clinical studies play a role:

“Because these are very large, complex molecules—unlike small molecules—those small differences can really make big impacts on the efficacy and safety of these drugs. And while for some biologics we know those small differences are safe, for others we might not. That’s why the role of the FDA in determining when we can safely approve biosimilars, and when more testing is needed, is critically important. We cannot undermine the essential work the FDA does in guiding companies through this process.”

This sentiment is echoed by biosimilar manufacturers themselves. In a recent press release, Celltrion stated:

“Interchangeable designation provides confidence among patients and healthcare providers… [it] is a key differentiator that offers greater assurance.”
Celltrion FDA approval announcement

And these assertions are also borne out by available data. ASBM’s multi-specialty surveys of U.S. biologic prescribers revealed that:

• 85% of U.S. physicians support the current FDA standards for approving interchangeable biosimilars
• 89% say switching studies are important before allowing automatic substitution
• Only 11% support treating all biosimilars as interchangeable.

According to the Biosimilars Council, biosimilars have saved $36 billion since their introduction—a clear indication that the current framework is working. As policymakers look to the future, the goal should be to build on this success. Undermining standards may offer short-term gains for middlemen like insurers and PBMs, but risks long-term damage to patient trust and physician confidence.