As increasing numbers of highly-successful biologics come off patent, biosimilars are a promising area for investment, offering growth potential that is lacking in many other areas of the biopharma market. This two-part series examines the environment for third-party capital providers. Part 1 provides an introduction to this complex area, describing key players entering the biosimilars market, ongoing biosimilar trials and the rationale behind partnering. It then examines three hurdles that must be addressed: manufacturing, immunogenicity and data generation (from pharmacokinetic/pharmacodynamic studies and clinical trials). Part 2 describes three additional hurdles: access to capital, exclusivity and intellectual property, and commercialization.