Modern biotechnology and traditional drug development have much in common. The aim of both, for example, is to develop agents that combat or prevent disease. For this purpose they harness the latest advances in biology. Most patients probably don’t care whether a drug is produced by biotechnological or chemical methods: the main thing is that it works. But there are major differences in detail.

Almost all traditional drugs are small molecules. Most are relatively simple organic compounds containing a few important molecular groups. So-called therapeutic proteins are something entirely different.

Most therapeutic proteins are chemical messengers, enzymes or monoclonal antibodies.

Therapeutic proteins
Some occur naturally in the body. For example, many long-established biotechnological products, such as the hormones insulin and erythropoietin, are natural chemical messengers. These molecules are produced in genetically engineered cells that carry the genetic information for producing the human protein.

Bioengineered proteins are already being used to treat the following diseases:

• Hepatitis C: Pegylated (PEG) therapeutic protein. The PEG barrier obstructs the protein breakdown machinery in the body’s cells and thereby prolongs the drug’s duration of action.
• Renal anaemia: Recombinant erythropoietin. This drug, known as a continuous erythropoietin receptor activator, prolongs the activation of red blood cell production and has the advantage that it can be given less often than current agents, which is more convenient for patients on long-term treatment.