Thoughts on biosimilar drugs

What is your opinion on biosimilar drugs? Are they comparable to monoclonal antibodies?

John Marshall: It is a very controversial area. Certainly biosimilars are with us and they are not going away. It is a natural evolution: patents expire, patenters with strong products develop similar molecules. Certainly the advantage of biosimilars is undoubtedly access. With cost savings and competition in the market, prices are driven down and that helps to solve one of the limits of modern medicine, which is how we pay for these new costly therapies. So biosimilars will drive down the price both of the biosimilar and of the innovator through competition. We have already seen that in the European market, where they have been introduced. So improving access to therapy is an important advantage of biosimilars.

I think there are still some questions we need to answer. As I am sure you are aware, we used to trim biosimilars, because these molecules are similar but not identical to the innovator. This is the nature of biologic drugs: we cannot replicate 100% the innovator molecule.

We have some encouraging data from comparative clinical trials about similarity and efficacy but I think all of us really want to see longer-term data, and particularly as we enter a market where there may be not just one biosimilar for a given innovator but several, and depending on changes in reimbursement and bidding processes we could see our patients cycle not just from innovator to biosimilar but among several biosimilars over their career. We have no data on sensitization with that repeated switching behavior over time. I think that is the biggest clinical concern: if patients are switched among biosimilars, could they develop any drug antibodies with greater frequency and could that then attenuate long-term efficacy. I do not know, that may not be the case, but I think that is the biggest unresolved question related to the medical side of things.