Market diffusion of biosimilars in off-patent biologic drug markets across Europe

Biologics are among the most expensive pharmaceuticals but have begun to lose their exclusivity rights over the past 15 years, offering the possibility for biosimilar competition. Therefore, we examine the market diffusion of biosimilars across Europe.Using revenues and sales data from IQVIA, we identified 12 biologic substances facing first biosimilar competition between 2014 and 2020 in 25 European countries. We investigated biosimilar market share depending on product and market characteristics with beta regression. Moreover, we compared market diffusion across countries using multilevel modelling.The average market share of biosimilars at first biosimilar entry was about seven percent in the retail and hospital market and grew to 34.69% and 38.29% after 16 quarters, respectively. Quarters since first biosimilar entry had a positive but decreasing effect on biosimilar market share (p<.001 for both markets). Quarterly growth ranged from 0.006 (Netherlands) to 0.026 (Slovakia) in the retail market and from 0.007 (Hungary) to 0.040 (United Kingdom) in the hospital market.The diffusion increased over time across all European markets, although at different rates. Biosimilar market share was higher in the hospital market. Compared to generics, diffusion of biosimilars is much slower. If policymakers desire to increase biosimilar diffusion, they should aim at policies that increase competition and use countries with the highest diffusion rates as benchmarks.