Biologic products are a class of therapies whose composition depends on proteins derived from living cells. This is in contrast to traditional pharmaceuticals, which consist essentially of non-living chemical compounds. Among the best-known examples of biologic products are vaccines, insulin, and interferon.16
There are no two identical living cells; and, the environment to which a living cell is exposed can cause changes in the proteins it produces. This can affect the quality, safety, and efficacy of the biosimilar product, compared to the originator-brand product. For example, changes in proteins produced by the living cell may cause antibodies to the biologic product in the body of the patient. For these reasons, the methods of producing biologic products are complex and require advanced technology; and hence, their reproduction or imitation, is considered a matter of the utmost difficulty, especially since the safety, quality and effectiveness and of the biologic product depend basically on its manufacturing process. It is therefore recognised by scientists that biologic products require about two thousand tests to be conducted during the manufacturing process to ensure its QSE. By contrast, traditional pharmaceuticals require only one hundred tests for these purposes.17
Since there are radical differences between traditional pharmaceuticals and biologic products in terms of composition and production process, the reproduction or imitation of biologic products differs significantly from the reproduction of traditional pharmaceuticals, known as generic drugs. Experts in the field are therefore keen on using different terms to distinguish between generic medicines, and imitated biologic products; and have hence called them "biosimilar products".
Notwithstanding the slight differences within the different drug registration authorities worldwide, there is general agreement on the main requirements that must be met for the approving the registration of generic drugs. The most important among these is that the generic drug must be bioequivalent to the originator-brand drug, meaning that the two drugs are essentially equivalent in both their QSE and use indications.18 Thus the generic drug contains the same active ingredient as the originator-brand drug, is identical to it in terms of quality, safety, efficacy and has the same dosage form; thus, making