When patents expire on medicines made with chemicals (such as aspirin, paracetamol or prednisone) it is straightforward for different pharmaceutical companies to make identical versions (generics) of the original brand. This is because these medicines are made by combining specific chemical ingredients in a defined and ordered process, making them relatively simple to duplicate: Chemical A + Chemical B = Medicine C.

In contrast, biological medicines are made using complex living cells and the manufacturing process is extensive. That is why all biologics, including original-brand biologics, have some degree of variability. In fact, biological medicines are so complex that they can even vary from batch to batch . This inherent natural variability (called “microheterogeneity”) is tightly controlled by the manufacturer and the health authorities to ensure the same clinical outcome from the biological medicine.

When patents expire on original-brand biologics, different pharmaceutical companies are allowed to make these medicines, which have become known as biosimilars. Biosimilars have the same active ingredient as an existing, approved biologic3. To gain approval for use by regulatory authorities, a biosimilar has to match the original-brand biologic in terms of safety and efficacy, demonstrating no clinically meaningful differences so patients can expect the same clinical outcome^1,2,3.

To manage this natural variability in a particular biological medicine (in original-brand biologics and biosimilars), any variations have to stay within precise ranges to maintain clinical efficacy and safety. These ranges are set and tightly controlled by both the regulatory authorities and the pharmaceutical company, to ensure that all batches of any one biologic are similar^1,2,3.

In fact, the term biosimilar can only be used to describe a biological medicine that has gone through a thorough process of laboratory analysis, pre-clinical testing and clinical trials in patients comparing the biosimilar to the original brand. This process is designed to demonstrate that the biosimilar matches the original-brand biologic in terms of safety and efficacy in patients^1,8. A product is designated a “biosimilar” by the regulatory authority, so this term is a validation of its quality and comparability. And of course, once approved, biosimilars are as closely monitored as original-brand biologics to ensure their continuing safety³.

5 Facts about Biosimilar Medicines [1]

Even though it takes many years to develop and gain approval for use of a biosimilar, it is likely that there will be a difference in price between them and original-brand biologics. This means that once they are approved for use, depending on the approaches of different healthcare authorities, biosimilar medicines have the potential to^1,4:

• Cause healthcare providers to reassess existing guidance about use of a particular biologic based on considerations around cost-effectiveness. 
• Make treatment more affordable for patients in certain countries who co-pay for their medicines.
• Allow health systems to redirect funds so that more patients can be treated.
• Allow some healthcare systems to use these innovative treatments for their citizens for the first time.
• Release resources to help healthcare systems to keep pace with growing healthcare needs and fund new generations of innovative treatments so that access to treatments, patient care and patients’ lives can all be improved with a sustainable approach.