Current State of Biosimilars: Approval, Availability, and Efficacy

Bruce Feinberg, DO: Bhavesh, given the complexity, the FDA went through a pretty elaborate process to determine approvals. Taking what Michael just said in mind, as well as the prior comments you made, are you comfortable with the process the FDA is using? Do you think the extent of comfort that you have is easy to share with clinicians who don’t have the same of pharmacology background?

Bhavesh Shah, RPh, BCOP: This is where pharmacists really play a huge role, because we understand a lot of the structural, pharmacokinetic, and pharmacodynamic similarities that you see in the process that the FDA has established for looking at a biosimilar versus a reference product. In the primary structure—which is the amino acid—the secondary structure, and even the tertiary structure, there have to be similarities established before they actually move on to the next stage, which has to do with the pharmacokinetics. You’re looking at T_Max, C_Max, and AUC [area under the curve]; all these things have to be similar to the biologic reference product. If they’re not, then it can’t move on to the next phase of the FDA process in approval.

I think that it is a well-established process. We are a bit behind compared with our European colleagues, right? They have over a decade of experience with these agents in practice, so the safety and efficacy of these drugs are well established across the waters.

Bruce Feinberg, DO: That efficacy is an important issue for biosimilars. The number of large studies done in this country are fewer, and the number in oncology are really quite a few, even across the pond. Most of that experience in the European Union is around the drugs that have been used in the rheumatologic population.

In this country, other than filgrastim, I don’t know if there are 7 or 9 now that have been approved, but it seems that all those approvals have not necessarily resulted in market availability and market access.

Bhavesh, from your perspective, if we focus a little on oncology, what do we really have now, in terms of available biosimilars on the market in the immediate term and in the near term? Give me some thoughts about the data that support their efficacy.

Bhavesh Shah, RPh, BCOP: Looking at the oncology landscape for biosimilars, we have 5 trastuzumab biosimilar molecules. We have 4 pegfilgrastim biosimilar molecules. There are 2 rituximab molecules for biosimilars, and then there are 2 bevacizumab molecules. Of course, there are more biosimilars coming for each of these other agents, so we anticipate that that’s going to continue to go up.

In terms of efficacy, it all depends on the drug and the indication that you are testing in. For example, for pegfilgrastim, as you know, the FDA didn’t need that molecule to be tested in patients with chemotherapy-induced neutropenia for it to be approved. They actually had a great structural and functional comparison, which showed that this was highly similar. Basically, they had the studies done in healthy subjects, which makes sense if you’re thinking about looking for immunogenicity. You want to look for it in patients who are not getting chemotherapy, which could blunt the immunogenicity signals that you’re looking for. There is a well-established process in oncology in which the FDA decides where you need to test these drugs, what indications are more sensitive, and how the trials need to be designed.

Bruce Feinberg, DO: Michael, I want to bring you back in because given all the biosimilars that are going to be entering the oncologic market, it brings up a lot of interesting questions for the oncologist who may be prescribing them.

One is, are they too late? Many of the reference brands for these drugs are already experiencing competitors that may be called next-generational. We are clearly seeing that with regard to some of the products—whether it’s Gazyva as next generation to rituximab. Clearly, we could argue the same with others.

Then we have questions about how, as we’re moving into cell and gene therapy, immuno-oncology, and a greater amount of targeted therapy, it feels like the monoclonal antibodies are almost in a prior generation.

I’m curious about where you see the current environment. We have filgrastim; we’re waiting for pegfilgrastim. We’ve got pegfilgrastim now, which to a large extent, is delivered via Onpro. We have a delivery device that is patented and is not being copied by the biosimilar. There is that “Is it too little too late” phenomenon, and I’m curious what you think about that, because it sounds like a lot of drugs and a lot of opportunity, but where is that reality check?

Michael Diaz, MD: That’s a very good question. They’ve had biosimilars available in other countries for many years. The U.S. is a bit late getting to this market, compared with others, but I look at biologics as being here to stay for some time. There are so many different disease indications. There are so many unique disease indications for which it would still take many years to find an equivalent or better substitute for a lot of the biologics that we have.

You also have to look at it from a couple of other perspectives. For newer medications, as they come out, they tend to be a little more economically costly. If you can achieve the same thing with a less expensive product, then I think we owe it to society to make the best use of our resources and use the less expensive product if we can. We could have used them a long time ago, but there are a lot of advantages that we can use to treat patients and to make sure all patients have access to appropriate, good-quality, economically reasonable medical care as well.

I don’t think that it is too late. I think it is better late than never. It’s 1 of those situations, and I think we need to continue to evolve our use of biosimilars as much as we can and try to integrate them into our practice and care of patients, as medically responsible.