Biosimilars, Interchangeability, and Perceptions of Safety

Angus Worthing, MD, FACR, FACP: When we’re talking about the confidence in the biosimilar pathway and achieving biosimilarity, a lot of my colleagues and experts (in the biosimilars field) will discuss a biosimilar as being akin to a new batch or a new lot of a reference biologic drug. And the way we talk about that is we know that since 1998, when the first biologic in rheumatology was approved, that drug is different from the drug that’s coming under the same brand name now. It has shifted because of a change in manufacturing techniques (often improvements). We now know, with analytical detail and technology that’s available these days, that a biosimilar might be more like a current reference biologic than that reference biologic was similar to when it was started (when it was first FDA approved). And thinking of it in that light, you can consider a drug that has achieved biosimilarity status, according to FDA, as a new batch or a new lot of the reference product.

Ha Kung Wong, JD: I was just thinking that since you’re a specialist, that might be something that you would look one step further at (to figure that out). But for the average healthcare provider, they may be looking at this from the perspective of the history with small molecules, where you have a generic drug which has an exact ingredient that’s identical. They say that a pharmacy, or a pharmacist can actually make that substitution and that the interchangeable is really kind of the biologic version of that. Whereas, the biosimilar is just another product. So, in some ways, if you’re looking at it as somebody who’s not digging deeper, doesn’t it somehow make it sound like the interchangeable has been blessed by the FDA as being safer or substitutable for this product?

Molly Burich, MS: Yes, I think that that’s certainly part of what some people are thinking. I think the FDA has made it very clear that that is not true—that it’s less safe because, of course, the hurdle for biosimilarity is where you determine whether the product has enough of the analytical similarity to be considered similar. But I definitely agree. There will be that perception, and I think that, in part, that’s why Europe doesn’t have the designation of interchangeability. And the reason for that is because they believe in the science of biosimilarity. They leave it up to the individual countries to decide. Hindsight is 20/20, right? We’re only 7 years in (in the United States), but I think that thinking that there could be a perception that an interchangeable is a higher quality product or has a higher level of safety or efficacy is incorrect. I think the FDA will continue to try and reiterate that. The reason why they’re 2 different designations is they’re approving 2 different things. It’s a worthwhile point because I think stakeholders, as they learn more about it, couldn’t actually go to that. And the truth is, it’s a different pathway and it’s a different approach from small molecules for many reasons, and the least of which is the complexity of the molecules.

Angus Worthing, MD, FACR, FACP: Molly brings up Europe and I think that’s an astute observation. The difference between the biosimilar pathway and the interchangeable pathway is probably in the eye of the beholder, at this point. For me, biosimilar designation means that a drug is expected to work as well and have the same safety issues as the reference product. Like I said—a new batch of the old reference product. On the other hand, I think interchangeability is an excellent idea in the multi-payer, multi-state market (like in the United States as compared to Europe), because patients that I prescribe drugs for can be expected to move, change insurances, graduate into Medicare or their formulary, or their same old insurance might change year to year. They may actually expect to switch back and forth from a reference product to a biosimilar, so I’m thrilled that the FDA proposes to study drugs like that.