Biosimilars: recent developments.

Biopharmaceuticals are recombinant protein drugs which are produced by biotechnology. The availability of such molecules has revolutionised the way we treat many diseases. However, the patents for many originator biopharmaceuticals are expiring, and a new generation of follow-on molecules, termed "biosimilars", are under development. Health care providers perceive biosimilars to be cheap replacements for originator drugs such as recombinant human erythropoietin and human growth hormone. However, concerns have been raised about the comparability of biosimilars with originator products especially in light of the complex manufacturing process required to produce biopharmaceuticals. The complexity of protein molecules renders it impossible to produce identical copies; this in turn raises questions on the safety of follow-on biosimilar products, particularly with respect to immunogenicity. This review briefly outlines the process of biopharmaceutical production, potential problems that can arise from their long-term use in patients, and the issues facing regulatory bodies as they look to institute guidelines for new biosimilar molecules.