One Year after the Launch of the First U.S. Biosimilar Drug: Lessons for the Future?

In September 2015, the first biosimilar drug, Zarxio, was launched on the U.S. market. While the impact of generic entry on the small molecule branded market in the U.S. is well-understood, the impact of biosimilar entry on the large molecule biologic market has only been studied in Europe and results suggest that the nature of competition depends greatly on country-specific features of the health care market. In this article, we examine Zarxio’s performance in the first year since its launch and evaluate to what extent that performance can be informative of future biologic-biosimilar competition in the U.S. Since many of the market mechanisms driving fast penetration of small molecule generic drugs in the U.S. are absent in the case of biosimilar drugs, biosimilar penetration is expected to be slower. Indeed, the penetration for Zarxio has so far been much more modest than the average for small molecule drugs: 22% by the end of the first year compared to 88% for small molecule generic drugs. We identify several reasons why Zarxio’s performance may understate the rigor of future U.S. biologic-biosimilar competition.