Modern biotechnology and traditional drug development have much in common. The aim of both, for example, is to develop substances able to cure or prevent disease. To achieve this they both rely on recent findings from the life science. For most patients it is a matter of indifference whether a drug is obtained by biotechnological or chemical means. The main thing is that it works. However, beneath the surface there are striking differences between the two kinds of drug product.

Almost all traditional drugs are small molecules. They are usually relatively simple organic compounds containing a few functional molecular groups. On the other hand, therapeutic proteins, the largest group of biopharmaceuticals, are quite a different kettle of fish.

Most therapeutic proteins are chemical messengers, enzymes or, especially in recent times, monoclonal antibodies. Some occur naturally in the body. For example, many long-established biotechnological products such as the hormone insulin and erythropoietin are natural chemical messengers. Now these molecules can be produced in genetically modified cells that carry the hereditary information for producing the human protein.