Biosimilars: current status and future directions.

IMPORTANCE OF THE FIELD: Expiration of patents covering biopharmaceuticals, has provided opportunities for pharmaceutical companies to develop, produce and market biosimilars or follow-on biologicals. However, there have been concerns over the degree of similarity of these complex drugs in addition to the hope that their introduction may lower the cost of such expensive medicinal products. AREAS COVERED IN THIS REVIEW: The introduction/manufacturing considerations, immunogenicity and regulatory approaches to biosimilars around the world. In addition, arguments and techniques employed by pharmaceutical companies to advance or discredit biosimilar drugs will be outlined. Issues with post-marketing surveillance programmes and their limitations are described. WHAT THE READER WILL GAIN: This evaluation outlines the controversial issues associated with introduction of biosimilar medicines across a range of pharmacological indications. Also the differences between regulatory approved medicines and biopharmaceutical products not subjected to regulatory approval ('B-NSRA') are highlighted. The review is limited by the rapid changes in regulatory approval and licencing of biosimilars. TAKE HOME MESSAGE: Hopefully biosimilar medicines will allow more widespread availability of expensive biopharmaceutical products. Clinicians need to be wary of non-transparent promotion of innovator/biosimilar products.