Sonia T. Oskouei, PharmD, BCMAS, DPLA, from Cardinal Health, explains the ramifications that interchangeability designations will have on biosimilars and when we might see the first interchangeable biosimilar in the United States.
Sonia T. Oskouei, PharmD, BCMAS, DPLA, is the vice president of Biosimilars at Cardinal Health.
How does the lack of interchangeability status impact access to biosimilars in the United States?
What's important to understand is how interchangeability designation is obtained and the implications associated with that designation in the US. So, first and foremost, interchangeability is a regulatory designation that is unique to the United States. It's not a clinical designation, so it doesn't denote clinical superiority or a higher quality product in any way compared to a biosimilar that doesn't have the designation.
Second, it's important understand how this designation is attained by biosimilar candidates, which is through the submission of additional data. Current guidance by the FDA says these biosimilars have to conduct switching studies, whereby you switch back and forth 3 times to show no differences in outcome. So, it's through the submission of that dat; that is what is used for the designation.
Probably what's most important with interchangeability is the implications of it, which is to enable pharmacist-level substitution per state laws. Therefore, interchangeability will have the greatest relevance and/or impact for those biosimilars that will be dispensed in the retail pharmacy setting or specialty pharmacy and are billed under the pharmacy benefit.
So, it makes sense that for the biosimilars we currently have available today, which are primarily medical benefit biosimilars, we don't see any with interchangeability designation. In fact, the only products that we know that are seeking interchangeability designation are insulins and a few adalimumab biosimilars. And that can make sense given where and how these products are utilized and dispensed.
So, where I see the lack of interchangeability potentially having the greatest impact in terms of adoption, is from the potential misconception of what it actually represents, which could serve as a barrier for adoption by creating clinical hesitancy for biosimilars that don't have the designation. Again, this is highlighting the significant role and the continued need for education on this topic.
Will we see the first interchangeable biosimilar this year? What difference would that make?
Absolutely. So, we are anticipating our first interchangeable biosimilars this year; in fact, this summer, with insulins. Just as we were discussing interchangeability, it's important to note that when insulins got transitioned to be regulated as biologics back in March 2020, the FDA also created updated guidance for insulin specifically for interchangeability, saying that switching studies may be unnecessary to support demonstration of interchangeability. Basically, this is clearing the path for insulin to achieve this designation more easily.
With that said, we're anticipating our first interchangeable biosimilars, with a long-acting insulin biosimilar and a short-acting insulin biosimilar this summer. We are eagerly awaiting this significant milestone in US biosimilar history to finally experience an interchangeable biosimilar in the market and, additionally, our first true retail biosimilar as well.
Although the full implications of having these products finally available is really unknown, there's such significant potential, especially with insulin products, where there's strong pricing scrutiny associated with insulins and really a high demand for affordable diabetes care in the US. So, I think there's going to be a lot of eyes on this activity. In terms of impact, I do think the designation will help as a differentiator, in the sense that it can help give that extra stamp of approval to alleviate any potential clinical concerns with the biosimilars.
But the extent of the impact from the designation will ultimately be determined by the managed care landscape and particularly PBMs [pharmacy benefit managers] and payers in how they react to it. For example, if we have an interchangeable biosimilar, which ultimately would allow pharmacists-level substitution per state law—but a PBM formulary prefers the originator biologic due to various economic incentives—this could essentially restrict or inhibit the ability of the biosimilar to be utilized. So, there's still quite a bit of unknowns and factors that will ultimately dictate how interchangeable biosimilars will perform in the market.